90 results on '"Cristian Morari"'
Search Results
2. The effect of translation on the binding energy for transition-metal porphyrines adsorbed on Ag(111) surface
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Luiza Buimaga-Iarinca and Cristian Morari
- Subjects
Ag(111) surface ,DFT+U ,metal porphyrine ,van der Waals ,Technology ,Chemical technology ,TP1-1185 ,Science ,Physics ,QC1-999 - Abstract
The characteristics of interaction between six transition-metal porphyrines and the Ag(111) surface are detailed here as resulted from DFT calculations. Van der Waals interactions as well as the strong correlation in 3d orbitals of transition metals were taken into account in all calculations, including the structural relaxation. For each system we investigate four relative positions of the metallic atom on top the surface. We show that the interaction between the transition metal and silver is the result of a combination between the dispersion interaction, charge transfer and weak chemical interaction. The detailed analysis of the physical properties, such as dipolar and magnetic moments and the molecule–surface charge transfer, analyzed for different geometric configurations allows us to propose qualitative models, relevant for the understanding of the self-assembly processes and related phenomena.
- Published
- 2019
- Full Text
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3. A roadmap for building quantum key distribution devices.
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Teodora Murariu, Andra Pastrav, Carmen Tripon, Cristian Morari, Emanuel Puschita, and Liviu P. Zârbo
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- 2022
- Full Text
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4. Combined molecular and periodic DFT analysis of the adsorption of co macrocycles on graphene.
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Adrian Calborean, Cristian Morari, and Pascale Maldivi
- Published
- 2018
- Full Text
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5. Effectiveness of electromagnetic shielding in the case of electromagnetic shields based on ferromagnetic materials
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RALUCA MARIA AILENI, CRISTIAN MORARI, DOINA TOMA, and LAURA CHIRIAC
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Polymers and Plastics ,Materials Science (miscellaneous) ,General Business, Management and Accounting ,General Environmental Science - Abstract
This paper presents a study concerning the effectiveness of electromagnetic shielding of textile structures coated with ferromagnetic materials. For this scientific approach, 6 experimental models of composites-based fabrics with electromagnetic properties were made by applying paste/dispersion based on polymeric matrices (polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP)), copper microparticles (Cu), nickel (Ni), aluminium (Al), silver (Ag), and graphene oxide (GO) using classical deposition (immersion, scraping) and ultrasonic technologies. The effectiveness of electromagnetic shielding has been evaluated using a coaxial cell model TEM 2000, oscilloscope model MDO 3102, power amplifier Model SMX5, signal generator type E8257D. The measurements were performed in the frequency range 0.1 MHz – 1 GHz and power 30 W. from all samples, the samples based PVA-Ni and PVA-Ni-Al exhibit pronounced surface conductivity and increased effectiveness of electromagnetic shielding for low and high frequencies.
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- 2022
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6. Induced Fit and Mobility of Cycloalkanes within Nanometer-Sized Confinements at 5 K
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Aisha Ahsan, Luiza Buimaga-Iarinca, Thomas Nijs, Sylwia Nowakowska, Rejaul Sk, S. Fatemeh Mousavi, Mehdi Heydari, Meike Stöhr, Sameena S. Zaman, Cristian Morari, Lutz H. Gade, Thomas A. Jung, and Surfaces and Thin Films
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General Materials Science ,Physical and Theoretical Chemistry - Abstract
Host–guest architectures provide ideal systems for investigating site-specific physical and chemical effects. Condensation events in nanometer-sized confinements are particularly interesting for the investigation of intermolecular and molecule–surface interactions. They may be accompanied by conformational adjustments representing induced fit packing patterns. Here, we report that the symmetry of small clusters formed upon condensation, their registry with the substrate, their lateral packing, and their adsorption height are characteristically modified by the packing of cycloalkanes in confinements. While cyclopentane and cycloheptane display cooperativity upon filling of the hosting pores, cyclooctane and to a lesser degree cyclohexane diffusively redistribute to more favored adsorption sites. The dynamic behavior of cyclooctane is surprising at 5 K given the cycloalkane melting point of >0 °C. The site-specific modification of the interaction and behavior of adsorbates in confinements plays a crucial role in many applications of three-dimensional porous materials as gas storage agents or catalysts/biocatalysts.
- Published
- 2022
7. On-site Performances Evaluation of Photovoltaic Panels Affected by Bypass Activated Diodes Detected with Thermal Cameras
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Alexandru-Ionel Constantin, Dorian Marin, Paula Angheliţă, Ioan Tiberiu Şerban, Cristian Morari, and Gabriela Iosif
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- 2023
- Full Text
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8. Revealing the Reversible Solid-State Electrochemistry of Lithium-Containing Conjugated Oximates: Towards a New Functionality for Organic Batteries
- Author
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Jiande Wang, Petru Apostol, Darsi Rambabu, Xuelian Liu, Xiaolong Guo, Koen Robeyns, Alae Eddine Lakraychi, Cristian Morari, Jean-Francois Gohy, Deepak Gupta, and Alexandru Vlad
- Abstract
In the rising advent of organic Li-ion positive electrode materials with increased energy content, chemistries with high redox potential and intrinsic oxidation stability, while in the lithium containing (Li-ion) form, remain a challenge. Molecular engineering of carbonyl compounds and of conjugated sulfonamide chemistries, have provided ground for future developments, while also inciting the search for other organic chemistry functions or classes, with alike properties, and with further improved energy storage metrics. Herein, we report on the solid- phase reversible electrochemistry of a new class of organic redox functionality for batteries, the lithium salts of conjugated oximates. The disclosed first five examples of the oximate class, including cyclic (aromatic), and acyclic (non-aromatic), as well as aliphatic and tetra-functional stereotypes, uncover the complex interplay between the molecular structure and the electroactivity, as well as the potential of this rich family as Li-ion positive electrode materials for batteries. Amongst the exotic features specific to this class of materials, the most appealing one is the reversible electrochemical polymerization – depolymerization accompanying the charge storage process in solid phase, through intermolecular azodioxy coupling (-ONNO-) or the intramolecular furoxan cyclization of the oxidized forms. Over the disclosed materials, the best performing candidate delivers a high reversible capacity of 350 mAh g-1 at an average potential of 3.0 vs. Li+/Li0, attaining 1 kWh kg-1 specific energy content at the material level metric. This work ascertains a strong link between the electrochemistry, organic chemistry and battery science by emphasizing on how different phases, mechanisms and performances can be accessed using a single chemical functionality.
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- 2023
- Full Text
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9. Revealing the reversible solid-state electrochemistry of lithium-containing conjugated oximates for organic batteries
- Author
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Jiande Wang, Petru Apostol, Darsi Rambabu, Xiaolong Guo, Xuelian Liu, Koen Robeyns, Mengyuan Du, Yan Zhang, Shubhadeep Pal, Robert Markowski, Fabio Lucaccioni, Alae Eddine Lakraychi, Cristian Morari, Jean-François Gohy, Deepak Gupta, Alexandru Vlad, UCL - SST/IMCN/MOST - Molecular Chemistry, Materials and Catalysis, and UCL - SST/IMCN/BSMA - Bio and soft matter
- Subjects
Multidisciplinary - Abstract
In the rising advent of organic Li-ion positive electrode materials with increased energy content, chemistries with high redox potential and intrinsic oxidation stability remain a challenge. Here, we report the solid-phase reversible electrochemistry of the oximate organic redox functionality. The disclosed oximate chemistries, including cyclic, acyclic, aliphatic, and tetra-functional stereotypes, uncover the complex interplay between the molecular structure and the electroactivity. Among the exotic features, the most appealing one is the reversible electrochemical polymerization accompanying the charge storage process in solid phase, through intermolecular azodioxy bond coupling. The best-performing oximate delivers a high reversible capacity of 350 mAh g −1 at an average potential of 3.0 versus Li + /Li 0 , attaining 1 kWh kg −1 specific energy content at the material level metric. This work ascertains a strong link between electrochemistry, organic chemistry, and battery science by emphasizing on how different phases, mechanisms, and performances can be accessed using a single chemical functionality.
- Published
- 2023
10. Case Study Related to the Maintenance and On-Site Detection of Faulty Photovoltaic Panels in a 14 Years Old System Based on Thermal Camera
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Alexandru-Ionel Constantin, Dorian Marin, Paula Anghelita, Ioan Tiberiu Serban, Cristian Morari, and Gabriela Iosif
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- 2022
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11. Predictive Analysis of the Electromagnetic Shields Effectiveness
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Raluca Maria Aileni, Elena Cristina Stroe, and Cristian Morari
- Abstract
This paper presents a predictive analysis of the electromagnetic attenuation effectiveness for conductive textile materials obtained by coating with polypyrrole, conductive paste-based aluminum, nickel, copper, silver, and graphene oxide. The predictive analysis was provided by the multiple regression modeling of the effectiveness of electromagnetic attenuation at 5 MHz, respective 700 MHz frequency depending on independent variables such as mass (M [g/m2]) and thickness (δ [mm]) of the fabric coated with the conductive paste by screen printing. Usually, flexible electromagnetic shields, based on textile materials, are necessary for shielding electric fields, representing a potential reference for cables and filters and ensuring the return path of parasitic currents. Protection against the harmful action of electromagnetic fields can be achieved using textile screens based on conductive coatings that ensure the reflection of the waves when they meet the surface, respectively, the absorption of the waves. In general, the wave representing the incident electromagnetic field propagates in the direction of the screen, undergoing a reflection at contact with the screen, then repeated internal reflections inside it, part of the wave being transmitted into the protected space.
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- 2022
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12. Stainless Steel and Copper Magnetron Plasma Coating of Fabrics with Metallic Yarns for Electromagnetic Shielding Applications
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Ion Razvan Radulescu, Emilia Visileanu, Razvan Scarlat, Cristian Morari, Cristian Stancu, and Bogdana Mitu
- Abstract
Electromagnetic shielding is needed to protect human beings from undesired non-ionizing radiation and to protect electronic equipment from EM interferences. Shielding solution of Electromagnetic Compatibility domain is tackled nowadays by modern manufacturing methods of flexible textile fabrics with electrically conductive properties. Our research focuses on the additional electromagnetic shielding effectiveness (EMSE) rendered by plasma coating of flexible woven fabrics with inserted conductive yarns. EMSE was computed for an experimental plan formed of plasma coating with Copper and Stainless steel with thicknesses of 400 nm and 1200 nm on both sides of woven fabrics with inserted conductive yarns of stainless steel and silver. An additional EMSE of 5-20 dB on the frequency range of 0.1-1000 MHz was achieved by plasma coating. This proves the enhancement of the shielding properties by magnetron plasma coating, without altering the bulk properties of textile fabrics, such as flexibility and mechanical resistance. The paper presents EMSE results in relation to fabric structure, raw metallic materials and frequency of the incident electromagnetic field.
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- 2022
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13. Calculation of infrared spectra for adsorbed molecules from the dipole autocorrelation function
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Luiza Buimaga-Iarinca and Cristian Morari
- Subjects
Physical and Theoretical Chemistry - Published
- 2022
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14. Modelling the Woven Structures with Inserted Conductive Yarns Coated with Magnetron Plasma and Testing Their Shielding Effectiveness
- Author
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Catalin Constantin, Ion Razvan Radulescu, Bogdana Mitu, Cristian Morari, Razvan Scarlat, Marian Costea, and Lilioara Surdu
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stainless steel yarns ,Textile ,Materials science ,business.industry ,silver yarns ,Shields ,02 engineering and technology ,Plasma ,fabrics ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,far-field radiation ,0104 chemical sciences ,electromagnetic shielding ,Transverse plane ,copper plasma coating ,Shield ,Electromagnetic shielding ,Cavity magnetron ,Composite material ,0210 nano-technology ,business ,Electrical conductor - Abstract
The paper proposes the analytic modelling of flexible textile shields made of fabrics with inserted conductive yarns and metallic plasma coating in order to calculate their electromagnetic shielding effectiveness (EMSE). This manufacturing process is highly innovative, since copper plasma coating improves EMSE on the fabrics with inserted conductive yarns of stainless steel and silver with 10–15 dB in the frequency range of 0.1–1000 MHz, as shown by the measured EMSE values determined according to the standard ASTM ES-07 via the Transverse Electromagnetic (TEM) cell. On the other hand, modelling of EMSE for such conductive flexible shields gives an insight on estimating EMSE in the design phase of manufacturing the shield, based on its geometric and electrical parameters. An analytic model was proposed based on the sum of EMSE of the fabric with inserted conductive yarns and EMSE of the copper coating. The measurement results show close values to the proposed analytic model, especially in case of fabric with conductive yarns having stainless steel content.
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- 2021
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15. New Cathode Materials in the Fe-PO
- Author
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Xuelian, Liu, Jiande, Wang, Mengyuan, Du, Koen, Robeyns, Yaroslav, Filinchuk, Qi, Zhu, Varun, Kumar, Yann, Garcia, Gheorghe, Borodi, Cristian, Morari, Jean-Francois, Gohy, and Alexandru, Vlad
- Abstract
Sodium and iron make up the perfect combination for the growing demand for sustainable energy storage systems, given the natural abundance and sustainability of the two building block elements. However, most sodium-iron electrode chemistries are plagued by intrinsic low energy densities with continuous ongoing efforts to solve this. Herein, the chemical space of a series of (meta)stable, off-stoichiometric Fe-PO
- Published
- 2022
16. Electromagnetic Compatibility of a Shielded Enclosure in the Presence of Conducted Perturbations
- Author
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Ana Lavinia Petrache, Jana Pintea, Vlad Brezoianu, Gabriela Iosif, Cristian Morari, and George Suciu
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Physics ,Control and Systems Engineering ,law ,Acoustics ,Shielded cable ,Electromagnetic compatibility ,Enclosure ,Electrical and Electronic Engineering ,law.invention - Published
- 2020
- Full Text
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17. Synthesis and Characterization of Water Dispersible Iron Oxide (�a-Fe2O3) Nanoparticles for Biomedical Applications
- Author
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Delia Patroi, Cristian Morari, G. Georgescu, Teodora Malaeru, Virgil Marinescu, Eugen Manta, E. Enescu, Magdalena Lungu, and E. Patroi
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Fe2o3 nanoparticles ,Water dispersible ,Materials science ,Process equipment ,Materials Science (miscellaneous) ,Process Chemistry and Technology ,General Engineering ,Iron oxide ,Nanotechnology ,General Chemistry ,General Medicine ,complex mixtures ,General Biochemistry, Genetics and Molecular Biology ,Characterization (materials science) ,chemistry.chemical_compound ,chemistry ,Petrochemistry ,Materials Chemistry ,General Pharmacology, Toxicology and Pharmaceutics - Abstract
In this study, L-lysine coated �a-Fe2O3 nanoparticles were synthesized by a chemical approach in two steps. In the first step �a-Fe2O3 nanoparticles were synthesized by a polyol-reduction method. XRD analysis confirmed the presence of cubic maghemite phase with an average crystallite size of 9.2 nm. SEM analysis showed that the prepared �a-Fe2O3 nanoparticles have a spherical structural morphology with the tendency of agglomeration and with size in the range 8.36- 10.69 nm. The �a-Fe2O3 nanoparticles were coated with L-lysine in the second stage in an aqueous dispersion with ultrasonication followed by a gentle heating at 40��C. FT-IR spectroscopy confirmed the presence of L-lysine on the nanoparticles surface and the Zeta potential also supported the coating of nanoparticles with a hydrophilic layer of amino acid (L-lysine) and a good stability in aqueous medium. Hysteresis loop shows a ferromagnetic behavior at room temperature for both samples.
- Published
- 2020
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18. Conductive textile structures and their contribution to electromagnetic shielding effectiveness
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Lilioara Surdu, Nicolae Golovanov, Bogdana Mitu, Cristian Morari, Ion Razvan Radulescu, and Marian Costea
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Materials science ,Polymers and Plastics ,Materials Science (miscellaneous) ,Conductive textile ,Composite material ,General Business, Management and Accounting ,General Environmental Science - Abstract
Fabrics for electromagnetic shielding are especially relevant in nowadays context, contributing to human’s protection and wellbeing and to proper functioning of electronic equipment, in relation to electromagnetic compatibility. Fabrics with electromagnetic shielding properties employ two main technologies, namely insertion of conductive yarns and application of conductive coatings. Magnetron sputtering is a modern technology to enable conductive coatings with thickness in the range of nanometers onto fabrics. This paper aims to analyze contribution of various conductive textile structures out of both fabrics with inserted conductive yarns and coatings to Electromagnetic shielding effectiveness (EMSE). EMSE was measured in the frequency range of 0.1–1000 MHz by using a TEM cell according to standard ASTM ES-07. Results show a gain of 10–25 dB when introducing silver yarns in warp/ weft direction, a variation of 5–35 dB between conductive yarns out of silver and stainless steel and an up to 12 dB gain out of thin copper coating by magnetron plasma onto the fabrics with inserted conductive yarns
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- 2020
- Full Text
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19. Life Cycle Assessment of Flexible Electromagnetic Shields
- Author
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Cristian Morari, Bogdana Mitu, Emilia Visileanu, Ion Razvan Radulescu, and Lilioara Surdu
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Materials science ,Shields ,Mechanical engineering ,Life-cycle assessment - Abstract
Nowadays, fiber based flexible electromagnetic shields have widespread applications in ensuring Electromagnetic Compatibility (EMC). Shielding is a solution of EMC, and the main methods to estimate shielding effectiveness are represented by the circuit method and the impedance method. Magnetron sputtering of metallic layers represents a novel technique to impart electric conductive properties to fabrics. Coating of fabrics represents a second main option to manufacture textile shields beside the insertion of conductive yarns in the fabric structure. Life Cycle Assessment (LCA) is often used to assess a comparatively modern with a classical manufacturing process in order to prove its eco-friendly character. This chapter comparatively assesses flexible EM shields manufactured of fabrics with inserted conductive yarns with and without magnetron plasma coating. The copper plasma coating of cotton fabrics with inserted silver yarns increases shielding effectiveness (EMSE) by 8–10 dB. In order to keep for the LCA study the same functional unit of 50 dB at 100 MHz for one sqm of fabric, the fabric structure is modeled with a reduced distance between the inserted conductive yarns. Results of the LCA study show a substantial impact on the environment for the plasma coated fabric upon using a laboratory scale deposition set-up.
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- 2022
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20. Revealing the Solid-State Electrochemistry of Conjugated Oximates: Towards a New Functionality for Organic Batteries
- Author
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Jiande Wang, Petru Apostol, Darsi Rambabu, Xuelian Liu, Xiaolong Guo, Koen Robeyns, Alae Eddine Lakraychi, Cristian Morari, Jean-Francois Gohy, Deepak Gupta, and Alexandru Vlad
- Abstract
In the rising advent of organic Li-ion cathodes with practical characteristic of being air-stable while in the reduced lithium-reservoir form, we report herein a new class of organic Li-ion positive electrode materials - the conjugated oximate lithium salts. The solid-phase electrochemistry of first five examples of the oximate class, including cyclic (aromatic), acyclic (non-aromatic), aliphatic and tetra-functional stereotypes, uncovers the complex interplay between the molecular structure and the electroactivity in the solid phase, as well as the potential of this rich family as cathode materials for lithium-ion batteries. The conjugation of oximate functions within the molecular core is found to endow excellent air stability of lithiated reduced phases, an important prerequisite for practical use as Li-ion positive electrode materials. Amongst the exotic features characterizing the solid-state electrochemistry of this class of materials, the most appealing one belongs to the reversible solid-state polymerization through intermolecular azodioxy coupling (-ONNO-) and the intramolecular furoxan cyclization of their oxidized forms. In the disclosed series of materials, the best performing candidate delivers high reversible capacity of 357 at an average potential of 3.0 vs. Li+/Li0, attaining over 1 KWh kg-1 specific energy content.
- Published
- 2022
- Full Text
- View/download PDF
21. New Cathode Materials in the Fe-PO4-F Chemical Space for High-Performance Sodium-Ion Storage
- Author
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Xuelian Liu, Jiande Wang, Mengyuan Du, Koen Robeyns, Yaroslav Filinchuk, Qi Zhu, Varun Kumar, Yann Garcia, Gheorghe Borodi, Cristian Morari, Jean‐Francois Gohy, Alexandru Vlad, UCL - SST/IMCN/MOST - Molecular Chemistry, Materials and Catalysis, and UCL - SST/IMCN/BSMA - Bio and soft matter
- Subjects
General Chemical Engineering ,General Engineering ,General Physics and Astronomy ,Medicine (miscellaneous) ,General Materials Science ,Genetics and Molecular Biology (miscellaneous) ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,Biochemistry - Abstract
Sodium and iron make up the perfect combination for the growing demand for sustainable energy storage systems, given the natural abundance and sustainability of the two building block elements. However, most sodium–iron electrode chemistries are plagued by intrinsic low energy densities with continuous ongoing efforts to solve this. Herein, the chemical space of a series of (meta)stable, off-stoichiometric Fe-PO4-F phases is analyzed. Some are found to display markedly improved electrochemical activity for sodium storage, as compared to the amorphous or thermodynamically stable phases of equivalent composition. The metastable crystalline Na1.2Fe1.2PO4F0.6 delivers a reversible capacity of more than 140 mAh g−1 with an average discharge potential of 2.9 V (vs Na+/Na0) resulting in a practical specific energy density of 400 Wh kg−1 (estimated at the material level), outperforming many developed Fe-PO4 analogs thus far, with further multiple possibilities to be explored toward improved energy storage metrics. Overall, this study unlocks the possibilities of off-stoichiometric Fe-PO4-F cathode materials and reveals the importance to explore the oft-overlooked metastable or transient state materials for energy storage.
- Published
- 2022
22. High performance Li-, Na-, and K-ion storage in electrically conducting coordination polymers
- Author
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Jiande Wang, Xiaolong Guo, Petru Apostol, Xuelian Liu, Koen Robeyns, Loïk Gence, Cristian Morari, Jean-François Gohy, Alexandru Vlad, UCL - SST/IMCN/MOST - Molecular Chemistry, Materials and Catalysis, and UCL - SST/IMCN/BSMA - Bio and soft matter
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Nuclear Energy and Engineering ,Sustainability and the Environment ,Renewable Energy, Sustainability and the Environment ,Environmental Chemistry ,Renewable Energy ,Pollution - Abstract
Coordination polymers (CPs) made of redox-active organic moieties and metal ions emerge as an important class of electroactive materials for battery applications. However, the design and synthesis of high voltage alkali-cation reservoir anionic CPs remains challenging, hindering their practical applications. Herein, we report a family of electrically conducting alkali-cation reservoir CPs with the general formula of A2-TM-PTtSA (wherein A = Li+, Na+, or K+; TM = Fe2+, Co2+, or Mn2+; and PTtSA = benzene-1,2,4,5-tetra-methylsulfonamide). The incorporation of transition metal centers not only enables intrinsic high electrical conductivity, but also shows an impressive redox potential increase of as high as 1 V as compared to A4-PTtSA analogues, resulting in a class of organometallic cathode materials with a high average redox potential of 2.95–3.25 V for Li-, Na- and K-ion batteries. A detailed structure – composition – physicochemical properties – performance correlation study is provided relying on experimental and computational analysis. The best performing candidate shows excellent rate capability (86% of the nominal capacity retained at 10C rate), remarkable cycling stability (96.5% after 1000 cycles), outstanding tolerance to low carbon content (5 wt%), high mass loading (50 mg cm−2), and extreme utilisation conditions of low earth orbit space environment tests. The significance of the disclosed alkali-ion reservoir cathodes is further emphasized by utilizing conventional Li-host graphite anode for full cell assembly, attaining a record voltage of 3 V in an organic cathode Li-ion proof-of-concept cell.
- Published
- 2022
23. A High-Voltage Organic Framework for High-Performance Na- and K-Ion Batteries
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Jiande Wang, Xuelian Liu, He Jia, Petru Apostol, Xiaolong Guo, Fabio Lucaccioni, Xiaozhe Zhang, Qi Zhu, Cristian Morari, Jean-François Gohy, and Alexandru Vlad
- Subjects
Fuel Technology ,Renewable Energy, Sustainability and the Environment ,Chemistry (miscellaneous) ,Materials Chemistry ,Energy Engineering and Power Technology - Published
- 2022
- Full Text
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24. On the contribution of phonons to electrochemical potential of Li-ion metal-organic frameworks
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Romulus Vlaeriu Flaviu Turcu, Luiza Buimaga-Iarinca, and Cristian Morari
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General Chemical Engineering ,Electrochemistry - Published
- 2023
- Full Text
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25. Leaf and hexagonal grid designs for lead-acid battery. An EIS analysis
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Adrian Calborean, Olivia Bruj, and Cristian Morari
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Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,Electrical and Electronic Engineering - Published
- 2022
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26. The effect of translation on the binding energy for transition-metal porphyrines adsorbed on Ag(111) surface
- Author
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Cristian Morari and Luiza Buimaga-Iarinca
- Subjects
Materials science ,Binding energy ,General Physics and Astronomy ,02 engineering and technology ,lcsh:Chemical technology ,010402 general chemistry ,lcsh:Technology ,01 natural sciences ,Full Research Paper ,Metal ,symbols.namesake ,Transition metal ,Atomic orbital ,Atom ,Nanotechnology ,van der Waals ,lcsh:TP1-1185 ,General Materials Science ,Electrical and Electronic Engineering ,lcsh:Science ,Magnetic moment ,lcsh:T ,Relaxation (NMR) ,Ag(111) surface ,021001 nanoscience & nanotechnology ,metal porphyrine ,lcsh:QC1-999 ,0104 chemical sciences ,Nanoscience ,Chemical physics ,visual_art ,symbols ,visual_art.visual_art_medium ,lcsh:Q ,van der Waals force ,0210 nano-technology ,DFT+U ,lcsh:Physics - Abstract
The characteristics of interaction between six transition-metal porphyrines and the Ag(111) surface are detailed here as resulted from DFT calculations. Van der Waals interactions as well as the strong correlation in 3d orbitals of transition metals were taken into account in all calculations, including the structural relaxation. For each system we investigate four relative positions of the metallic atom on top the surface. We show that the interaction between the transition metal and silver is the result of a combination between the dispersion interaction, charge transfer and weak chemical interaction. The detailed analysis of the physical properties, such as dipolar and magnetic moments and the molecule–surface charge transfer, analyzed for different geometric configurations allows us to propose qualitative models, relevant for the understanding of the self-assembly processes and related phenomena.
- Published
- 2019
- Full Text
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27. Time-dependent analysis of the state-of-health for lead-acid batteries: An EIS study
- Author
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Teodora Murariu and Cristian Morari
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Battery (electricity) ,Materials science ,Renewable Energy, Sustainability and the Environment ,State of health ,Constant phase element ,020209 energy ,Energy Engineering and Power Technology ,02 engineering and technology ,Function (mathematics) ,021001 nanoscience & nanotechnology ,Automotive engineering ,Dielectric spectroscopy ,0202 electrical engineering, electronic engineering, information engineering ,Equivalent circuit ,Electrical and Electronic Engineering ,0210 nano-technology ,Lead–acid battery ,Electrical impedance - Abstract
This paper presents a methodology to predict the evolution of state-of-health for lead-acid battery under controlled aging conditions. The results are based on the electrochemical impedance spectroscopy data. We show that by collecting impedance data for the battery for two states of charge (fully charged and at 75% SOC, respectively) it is possible to predict the lifetime of the battery with high accuracy. Our conclusion is based on the effect of linear decay for the values of constant phase element in the equivalent circuit of the battery during the aging. In order to validate our conclusions we perform analysis over three separate cells. We show that the linear decay as a function of cycle index is a robust feature, present for all samples. Potential application of our methodology include the rapid evaluation of the industrial products, the possibility to test the effect of technological changes over the battery quality as well as the development of optimized battery management systems.
- Published
- 2019
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28. Interlaboratory Comparison of Electromagnetic Fields in Power Supply Systems
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Claudia Pacurar, Claudia Constantinescu, Cristian Morari, Sergiu Andreica, Marian Gliga, Adina Giurgiuman, and Calin Munteanu
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Electromagnetic field ,Measurement method ,Atmospheric measurements ,Specific test ,Computer science ,Repeatability ,Power (physics) ,Reliability engineering - Abstract
This interlaboratory comparison is performed for two reasons: to ensure the repeatability of testing amongst EMC laboratories concerning specific test methods and to evaluate the testing capabilities of these laboratories. The purpose of this paper is to present the application of an interlaboratory comparison method for electromagnetic fields produced by power supply systems, involving two laboratories. An electromagnetic field generator with a frequency of 50 Hz, which is moved from one laboratory to another, is used in order to obtain the data for the final assessment. The results obtained were based on the three-point measurement method in accordance with the standard IEC 61786.
- Published
- 2021
- Full Text
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29. Modeling and Validating Analytic Relations for Electromagnetic Shielding Effectiveness of Fabrics with Conductive Yarns
- Author
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Cristian Morari, Marian Costea, Emilia Visileanu, Lilioara Surdu, and Ion Razvan Radulescu
- Subjects
010302 applied physics ,Materials science ,0103 physical sciences ,Electromagnetic shielding ,InformationSystems_INFORMATIONSTORAGEANDRETRIEVAL ,Mechanical engineering ,02 engineering and technology ,021001 nanoscience & nanotechnology ,0210 nano-technology ,01 natural sciences ,Electrical conductor ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) - Abstract
Electromagnetic (EM) radiation may be harmful for human’s health and for functioning of electronic equipment. The field of Electromagnetic Compatibility approaches various solutions to tackle this problem, while shielding of the radiation is one of the main solutions. Since the development of spinning technology for producing conductive yarns for fabrics, textile electromagnetic shields have become a valuable alternative to metallic shields. Their main advantages are given by the flexibility, the low weight and the good mechanical resistance, as well as by the possibility to precisely design the shield. The scientific literature includes several analytic relations for estimating the electromagnetic shielding effectiveness (EMSE), in case of woven fabrics with conductive yarns, which may be modeled as a grid of electric conductors. This book chapter tackles three different analytic models for estimating EMSE, which are useful to predict this functionality in the design phase of fabrics. The analytic relations are subsequently comparatively validated by EMSE measurements via TEM cell equipment of two woven fabrics with conductive yarns out of stainless steel and silver with a grid of 4 mm. Results of validated analytic relations are used for the approach of designing textile shields with regard to final application requirements.
- Published
- 2021
30. Pyrazinacenes exhibit on-surface oxidation-state-dependent conformational and self-assembly behaviours
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Francis D'Souza, Zuzana Burešová, S. Fatemeh Mousavi, Luiza Buimaga-Iarinca, Aisha Ahsan, Jan Labuta, David Miklík, Thomas A. Jung, Filip Bureš, Yutaka Wakayama, Cristian Morari, Anna Middleton, Pavel Švec, Katsuhiko Ariga, Yoshitaka Matsushita, Gary J. Richards, Jonathan P. Hill, Toshiyuki Mori, and Paul A. Karr
- Subjects
redox-active chromophores ,Materials science ,samoorganizující se ,Heteroatom ,redox-aktivní chromofory ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Redox ,Pentacene ,chemistry.chemical_compound ,Planar ,Materials Chemistry ,Environmental Chemistry ,Surface oxidation ,Multiplicity (chemistry) ,QD1-999 ,self-assembly ,General Chemistry ,Chromophore ,021001 nanoscience & nanotechnology ,pyrazinaceny ,0104 chemical sciences ,Chemistry ,chemistry ,Chemical physics ,pyrazinacenes ,Self-assembly ,0210 nano-technology - Abstract
Acenes and azaacenes lie at the core of molecular materials' applications due to their important optical and electronic features. A critical aspect is provided by their heteroatom multiplicity, which can strongly affect their properties. Here we report pyrazinacenes containing the dihydro-decaazapentacene and dihydro-octaazatetracene chromophores and compare their properties/functions as a model case at an oxidizing metal substrate. We find a distinguished, oxidation-state-dependent conformational adaptation and self-assembly behaviour and discuss the analogies and differences of planar benzo-substituted decaazapentacene and octaazatetracene forms. Our broad experimental and theoretical study reveals that decaazapentacene is stable against oxidation but unstable against reduction, which is in contrast to pentacene, its C-H only analogue. Decaazapentacenes studied here combine a planar molecular backbone with conformationally flexible substituents. They provide a rich model case to understand the properties of a redox-switchable pi-electronic system in solution and at interfaces. Pyrazinacenes represent an unusual class of redox-active chromophores. Acenes are a promising class of organic materials with distinctive electronic and optical properties. Here decaazapentacene and octaazatetracenes are prepared and their self-assembly behaviour at different oxidation states is analysed. Práce se zabývá studiem pyrazinacenů obsahujících dihydro-dekaazapentacenové a dihydro-oktaazatetracenové chromofory a porovnáním jejich vlastností při modelovém chování na oxidačním kovovém substrátu. Byla nalezena odlišná, na oxidačním stavu závislá konformační adaptace a samouspořádající se chování. Byly připraveny dekaazapentaceny a oktaazatetraceny a analyzováno jejich samoorganizující se chování v různých oxidačních stavech.
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- 2021
31. Conjugated sulfonamides as a class of organic lithium-ion positive electrodes
- Author
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Alae Eddine Lakraychi, Alexandru Vlad, Xuelian Liu, Cristian Morari, Louis Sieuw, Jiande Wang, Philippe Poizot, UCL - SST/IMCN/MOST - Molecular Chemistry, Materials and Catalysis, Institut de la matière condensée et des nanosciences / Institute of Condensed Matter and Nanosciences (IMCN), Université Catholique de Louvain = Catholic University of Louvain (UCL), Technical University of Cluj-Napoca, Institut des Matériaux Jean Rouxel (IMN), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Polytechnique de l'Université de Nantes (EPUN), and Université de Nantes (UN)-Université de Nantes (UN)
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Battery (electricity) ,Solid-state chemistry ,Materials science ,chemistry.chemical_element ,Organic chemistry ,Organic radical battery ,02 engineering and technology ,Conjugated system ,010402 general chemistry ,Electrochemistry ,7. Clean energy ,01 natural sciences ,Redox ,law.invention ,Batteries ,law ,General Materials Science ,Mechanical Engineering ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Combinatorial chemistry ,Cathode ,0104 chemical sciences ,chemistry ,Mechanics of Materials ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Lithium ,Materials chemistry ,0210 nano-technology - Abstract
International audience; The applicability of organic materials in conventional Li-ion batteries is challenging owing to the lack of lithium-containing and air-stable cathodes. A class of conjugated sulfonamides to be used as lithium-ion positive electrodes is now shown to exhibit reversible charge storage. The applicability of organic battery materials in conventional rocking-chair lithium (Li)-ion cells remains deeply challenged by the lack of Li-containing and air-stable organic positive electrode chemistries. Decades of experimental and theoretical research in the field has resulted in only a few recent examples of Li-reservoir materials, all of which rely on the archetypal conjugated carbonyl redox chemistry. Here we extend the chemical space of organic Li-ion positive electrode materials with a class of conjugated sulfonamides (CSAs) and show that the electron delocalization on the sulfonyl groups endows the resulting CSAs with intrinsic oxidation and hydrolysis resistance when handled in ambient air, and yet display reversible electrochemistry for charge storage. The formal redox potential of the uncovered CSA chemistries spans a wide range between 2.85 V and 3.45 V (versus Li+/Li-0), finely tunable through electrostatic or inductive molecular design. This class of organic Li-ion positive electrode materials challenges the realm of the inorganic battery cathode, as this first generation of CSA chemistries already displays gravimetric energy storage metrics comparable to those of the stereotypical LiFePO4.
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- 2021
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32. Translation of metal-phthalocyanines adsorbed on Au(111): from van der Waals interaction to strong electronic correlation
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Cristian Morari and Luiza Buimaga-Iarinca
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Multidisciplinary ,Materials science ,Magnetic moment ,Electronic correlation ,Binding energy ,lcsh:R ,lcsh:Medicine ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Article ,0104 chemical sciences ,symbols.namesake ,Dipole ,Transition metal ,Atomic orbital ,Chemical physics ,symbols ,Molecule ,lcsh:Q ,van der Waals force ,Physics::Chemical Physics ,0210 nano-technology ,lcsh:Science - Abstract
Using first-principles calculations, we investigate the binding energy for six transition metal - phthalocyanine molecules adsorbed on Au(111). We focus on the effect of translation on molecule - surface physical properties; van der Waals interactions as well as the strong correlation in d orbitals of transition metals are taken into account in all calculations. We found that dispersion interaction and charge transfer have the dominant role in the molecule-surface interaction, while the interaction between the transition metal and gold has a rather indirect influence over the physics of the molecule-surface system. A detailed analysis of the physical properties of the adsorbates at different geometric configurations allows us to propose qualitative models to account for all values of interface dipole charge transfer and magnetic moment of metal-phthalocyanines adsorbed on Au(111).
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- 2018
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33. Topological superconductivity from magnetic impurities on monolayer NbSe$_2$
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Doru Sticlet and Cristian Morari
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Superconductivity ,Materials science ,Condensed Matter - Mesoscale and Nanoscale Physics ,FOS: Physical sciences ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Coupling (probability) ,Topology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,MAJORANA ,Ferromagnetism ,Impurity ,Condensed Matter::Superconductivity ,0103 physical sciences ,Monolayer ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Ising model ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,0210 nano-technology ,Spin (physics) - Abstract
Recent experimental studies have found that magnetic impurities deposited on superconducting monolayer NbSe$_2$ generate coupled Yu-Shiba-Rusinov bound states. Here we consider ferromagnetic chains of impurities which induce a Yu-Shiba-Rusinov band and harbor Majorana bound states at the chain edges. We show that these topological phases are stabilized by strong Ising spin-orbit coupling in the monolayer and examine the conditions under which Majorana phases appear as a function of distance between impurities, impurity spin projection, orientation of chains on the surface of the monolayer, and strength of magnetic exchange energy between impurity and superconductor., Comment: 21 pages
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- 2019
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34. Supramolecular Architecturing of Quantum Box Arrays from Functionalized Porphyrins and Exploring Their Quantum States
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Thomas Nijs, Aisha Ahsan, Sylwia Nowakowska, Luiza Iarinca, Silvio Decurtins, Meike Stoehr, Igor A. Pašti, Olha Popova, Thomas A. Jung, Fatemeh S. Mousavi, Milos Baljozovic, Lutz H. Gade, François Diederich, Jorge Lobo Checa, Jonathan P. Hill, Cristian Morari, Carlo Thilgen, and Shi-Xia Liu
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Physics ,Quantum state ,Supramolecular chemistry ,Nanotechnology ,Quantum - Abstract
Our research is based on the analysis of structure-function correlations for a broad spectrum of functionalized porphyrins and phthalocyanines in their propensity to create increasingly complex and functional on surface architectures. [1] Thereby we use porphyrin and phthalocyanine functionalization and synthesis, ‘by design’, or ‘on-surface-supramolecular chemistry’ to create structures with specific physical properties towards e.g. future quantum devices. By using a fluoro-bi-phenyl functionalized porphyrin to create a stable, porous organic network, we manufacture arrays of identical quantum boxes. These boxes contain a specific quantum well state arising from the confinement of the electronic (Shockley) surface state within the pores. We show that the electronic quantum box state as well as the interbox coupling can be modified locally by adsorbates, e.g. C60, interacting with the barrier. In view of the wealth of available and differently acting adsorbates, this approach allows for the engineering of quantum states in on-surface network architectures. Thus, by their dance on the nose of the ‘devil’ [3], porphyrins and phthalocyanines justify the emergence of ‘on-surface supramolecular physics’ as reflected by ongoing and future research work. Fig. 1) Adsorbate-induced modification of the confining barriers in a quantum box array formed by a functionalized fluoro-bi-phenyl porphyrin on Ag(111). (Taken from [2]) [1] N. Wintjes et al. Two-dimensional phase behavior of a bimolecular porphyrin system at the solid-vacuum interface, J. Am. Chem. Soc. 2010, 132, 21, 7306-7311; N. Wintjes et al., Supramolecular synthons on surfaces: Controlling dimensionality and periodicity of tetraarylporphyrin assemblies by the interplay of cyano and alkoxy substituents Chem. Eur. J. 2008, 14, 5794. [2] S. Nowakowska et al., Adsorbate-induced modification of the confining barriers in a quantum box array, ACS Nano 2018, 12, 768. [3] W. Pauli “God made the bulk; surfaces were invented by the devil.” Quoted, e.g. in the Preface of A. Zangwill, Physics at Surfaces, Cambridge University Press, 1988. ISBN 978-0-521-34752-5 Figure 1
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- 2021
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35. Optimized lead-acid grid architectures for automotive lead-acid batteries: An electrochemical analysis
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Cristian Morari, Adrian Calborean, and Teodora Murariu
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Battery (electricity) ,Materials science ,Fabrication ,business.industry ,Constant phase element ,General Chemical Engineering ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Grid ,01 natural sciences ,0104 chemical sciences ,Dielectric spectroscopy ,Hardware_GENERAL ,Electrode ,Electrochemistry ,Optoelectronics ,0210 nano-technology ,Lead–acid battery ,business ,Intensity (heat transfer) - Abstract
A variety of technological approaches of lead-acid batteries have been employed during the last decades, within distinguished fabrication features of electrode grid composition, electrolyte additives, or oxide paste additives embodiment. We proposed in this study, a particular path for improving the efficiency of positive grids by developing two novel geometry designs of lead-acid battery metallic grids. Our projection is based on a hierarchical approach that employed exclusively rectangular shapes for the structural configuration of grids. The intensity of current distribution was firstly evaluated by a numerical algorithm across the electrodes grid surface, thus allowing measuring the propagation of the electric charge emitted from each point inside of the grid. The novel fabricated prototypes were investigated by electrochemical impedance spectroscopy, following a controlled aging procedure. Two distinct parameters were investigated for evaluation of batteries lifetime: i) a time-dependent analysis of Constant Phase Element – Q parameter at 75% SoC partially discharged, and ii) the resonance frequency of the circuit. To confirm our improvements, we compared the data with the ones of an industrial grid model. An increment of battery lifetime was obtained for one prototype, with an estimation growth of 25% - 28% over the usual industrial electrode, while for the later a slightly improved lifetime efficiency of about 10% was resulted.
- Published
- 2021
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36. The Effect of the Electric Field on the α-GPC Interaction with Au(111) Surface: A First-Principles Study
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Adrian Calborean, Cristian Morari, P. T. Vernier, Luiza Buimaga-Iarinca, and N. Ivošević DeNardis
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Physics ,Surface (mathematics) ,Molecular adsorption ,Deformation (mechanics) ,Binding energy ,Adsorbed molecule ,Geology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,symbols.namesake ,General Energy ,Nuclear magnetic resonance ,Chemical physics ,Electric field ,choline moiety ,electric field ,gold ,molecule-surface interaction ,symbols ,Moiety ,Physical and Theoretical Chemistry ,van der Waals force ,0210 nano-technology - Abstract
We present a theoretical investigation that addresses the most important aspects of the interaction between α-glycero-phosphatidyl-choline and Au(111) surface. For the density functional calculations we employed both traditional exchange-correlation functionals and newly developed vdW-D2 corrected one. The comparison between these functionals allows us to spot the role of van der Waals effects into the molecule– surface interaction. The effect of an external field applied to the molecule–surface system was also explicitly investigated. Our results reveal a complex picture where the molecular adsorption is dominated by the interplay between a weak molecule–surface interaction and a rather important deformation energy of the adsorbed molecule. In the presence of an external electric field, the choline moiety provided the strongest response in terms of binding energy as well as geometric configuration of the adsorbate.
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- 2016
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37. NMR study and computational assays of meclofenamic Na salt and β-cyclodextrin inclusion complex
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Mircea Bogdan, Cristian Morari, Luiza Buimaga-Iarinca, Adrian Pîrnău, and Călin G. Floare
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chemistry.chemical_classification ,Cyclodextrin ,010405 organic chemistry ,Chemical shift ,General Chemistry ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,Binding constant ,0104 chemical sciences ,Crystallography ,chemistry ,Computational chemistry ,Ab initio quantum chemistry methods ,Proton NMR ,Moiety ,Molecule ,SIESTA (computer program) ,Food Science - Abstract
Complexation in solution between meclofenamate sodium (MCF) and β-cyclodextrin was studied using one- and two-dimensional 1H NMR spectroscopy and molecular docking coupled with ab initio calculations. The large variation of chemical shifts from protons located inside the hydrophobic cavity of β-cyclodextrin, provided clear evidence of inclusion complexation. The stoichiometry of the inclusion complex was determined to be 1:1, using the method of continuous variation. To ascertain the solution geometry of the host–guest complex a ROESY experiment was carried out. The results suggested a preferential binding of the dichlorophenyl moiety of the guest molecule within the β-cyclodextrin cavity, conformation which also sustained by the theoretical computational investigations. The association constant of the inclusion complex was determined using 1H NMR titration method in solution followed by a non-linear least-square regression implemented in CONSTEQ, a software developed in our group. After a preliminary molecular docking investigation, the most probable conformation was subjected to ab initio calculations using SIESTA software package, to characterize more precisely the stabilization energy of the 1:1 inclusion complex.
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- 2016
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38. Weak interactions between tetraphenylporphyrin dimers: A Wannier orbitals study
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Cristian Morari, Teodor-Lucian Biter, and Luiza Buimaga-Iarinca
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Condensed Matter::Quantum Gases ,Physics ,Dimer ,Binding energy ,General Physics and Astronomy ,Interaction energy ,01 natural sciences ,Molecular physics ,010305 fluids & plasmas ,symbols.namesake ,chemistry.chemical_compound ,Pauli exclusion principle ,chemistry ,Atomic orbital ,0103 physical sciences ,Tetraphenylporphyrin ,Physics::Atomic and Molecular Clusters ,symbols ,Molecule ,van der Waals force ,010306 general physics - Abstract
We investigate the weak interactions taking place in the tetraphenylporphyrin dimers by using Wannier orbitals and DFT. The Van der Waals interaction energies for various geometric configurations of the dimers are then compared to the differences between the total DFT energies of dimers and those of sums over the energies of monomers. The comparison allows us to estimate the weight of the Van der Waals contribution to the total interaction energy since the DFT values include all contributions such as weak chemical interaction or Pauli repulsion to the binding energy. We show that the interaction energy computed with vdW-DF-cx exchange-correlation functional is almost identical with the one computed using Wannier orbitals. By analyzing the properties of Wannier orbitals in monomer and dimer structures, we check the fact the Van der Waals energy can be accurately calculated by using only the orbitals corresponding to the single molecule, which is useful from a practical perspective.
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- 2020
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39. On-Surface Supramolecular Chemistry with Porphyrins and Phthalocyanines: An Architectural Concept Leading to Engineered Quantum-Functional Nanostructures
- Author
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Cristian Morari, Aisha Ahsan, Jonathan P. Hill, Olha Popova, Fatemeh S. Mousavi, François Diederich, Luiza Iarinca, Igor A. Pašti, Thomas A. Jung, Sylwia Nowakowska, Silvio Decurtins, Lutz H. Gade, Jorge Lobo Checa, Meike Stoehr, Shi-Xia Liu, Carlo Thilgen, Thomas Nijs, and Milos Baljozovic
- Subjects
Surface (mathematics) ,Nanostructure ,Materials science ,Supramolecular chemistry ,Nanotechnology ,Quantum - Abstract
The availability of porphyrin and phthalocyanine functionalization and synthesis, ‘by design’, at the time when sub-molecular resolution imaging at surfaces came into action boosted the emergence of ‘On-Surface-Supramolecular Chemistry’. [1] It is instructive to compare supra-molecular binding motifs in the fluid phase with the corresponding or modified analogues found after assembly on surfaces. In some similarity to chemistry and coordination chemistry translating into the corresponding ‘on-surface’ sciences, there are many factors complicating the on-surface assembly and architecture. Examples are provided by the modified dimensionality and kinetics, the site-specific conformational flexure and chirality and the close to irreversible adsorption in the strong surface potential in absence of a solvent which may complicate the on-surface assembly and architecture. Further, porphyrins and phthalocyanines interact with the substrate by different, competitive interactions, i.e. via (1) the central metal atom and (2) the porphyrin pi-system in addition to (3) the functional side groups. Binary and ternary assemblies of porphyrins and other functional components make it possible to create a wealth of ‘phases’, i.e. different complex supramolecular architectures with interesting physical properties to explore and exploit. We analyze structure-function correlations for a broad spectrum of functionalized porphyrins and phthalocyanines in their propensity to create structures of increasing complexity and functionality, on surfaces, also for future quantum technology. Notably, the large delocalized electronic system of the porphyrins and their easy-to-replace central atom further extend the achievable range of architectures and functions. Thus, by their dance on the nose of the ‘devil’ [3], porphyrins and phthalocyanines justify the emergence of ‘on-surface supramolecular physics’ as reflected by ongoing and future research work. [1] N. Wintjes et al. Two-dimensional phase behavior of a bimolecular porphyrin system at the solid-vacuum interface, J. Am. Chem. Soc. 2010, 132, 21, 7306-7311; N. Wintjes et al., Supramolecular synthons on surfaces: Controlling dimensionality and periodicity of tetraarylporphyrin assemblies by the interplay of cyano and alkoxy substituents Chem. Eur. J. 2008, 14, 5794. [2] S. Nowakowska et al., Adsorbate-induced modification of the confining barriers in a quantum box array, ACS Nano 2018, 12, 768. [3] W. Pauli “God made the bulk; surfaces were invented by the devil.” Quoted, e.g. in the Preface of A. Zangwill, Physics at Surfaces, Cambridge University Press, 1988. ISBN 978-0-521-34752-5 Fig. 1) Adsorbate-induced modification of the confining barriers in a quantum box array formed by a functionalized fluoro-bi-phenyl porphyrin on Ag(111). (Taken from [2]) Figure 1
- Published
- 2020
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- View/download PDF
40. Resonance frequency analysis of lead-acid cells: An EIS approach to predict the state-of-health
- Author
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Adrian Calborean, Teodora Murariu, Olivia Bruj, and Cristian Morari
- Subjects
Battery (electricity) ,Work (thermodynamics) ,Materials science ,Renewable Energy, Sustainability and the Environment ,State of health ,020209 energy ,Energy Engineering and Power Technology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Dielectric spectroscopy ,Resonance frequency analysis ,State of charge ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,0210 nano-technology ,Lead–acid battery ,Biological system ,Electrical impedance - Abstract
We present in this work a new electrochemical impedance spectroscopy approach for lifetime prediction of lead-acid cells under imposed aging conditions. Frequency dependent impedance fluctuations are being monitored during charging and discharging sequences of battery for two distinct states of charges. We monitored the battery impedance behavior in two distinct states: at 100% state of charge, and secondly, at 75% state-of-charge. During the aging process, we encompassed the impedance plots vs frequency shifting diagrams, in the framework of a single parameter, we refer here to resonant frequency of the circuit. The validation of our model was demonstrated by comparing the resonance frequency values in three fabricated cells, thus emphasizing the changes that appear in the various physical details, depending on battery fabrication methodology. For State-of-Charge = 100% the degradation of the battery is leading to an important variation of its resonance frequency, while for State-of-Charge = 75%, the fluctuations of resonance frequency are significantly smaller. Monitoring just one parameter, we developed an accurate fitting model function capable to predict the lead-acid cells aging process. We can say that for the cell produced under controlled conditions, we get a larger lifetime and an inferior degradation speed to the cells manufactured in laboratory.
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- 2020
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41. Combined molecular and periodic DFT analysis of the adsorption of co macrocycles on graphene
- Author
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Pascale Maldivi, Cristian Morari, Adrian Calborean, Conception d’Architectures Moléculaires et Processus Electroniques (CAMPE), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
- Subjects
Materials science ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,law.invention ,symbols.namesake ,chemistry.chemical_compound ,Computational chemistry ,law ,Monolayer ,ComputingMilieux_MISCELLANEOUS ,Graphene ,Fermi level ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,Computational Mathematics ,chemistry ,Chemical physics ,Density of states ,symbols ,Phthalocyanine ,Density functional theory ,0210 nano-technology ,Bilayer graphene ,Graphene nanoribbons - Abstract
The molecular doping of graphene with π-stacked conjugated molecules has been widely studied during the last 10 years, both experimentally or using first-principle calculations, mainly with strongly acceptor or donor molecules. Macrocyclic metal complexes have been far less studied and their behavior on graphene is less clear-cut. The present density functional theory study of cobalt porphyrin and phthalocyanine adsorbed on monolayer or bilayer graphene allows to compare the outcomes of two models, either a finite-sized flake of graphene or an infinite 2D material using periodic calculations. The electronic structures yielded by both models are compared, with a focus on the density of states around the Fermi level. Apart from the crucial choice of calculation conditions, this investigation also shows that unlike strongly donating or accepting organic dopants, these macrocycles do not induce a significant doping of the graphene sheet and that a finite size model of graphene flake may be confidently used for most modeling purposes. © 2017 Wiley Periodicals, Inc.
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- 2018
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42. Subpicosecond surface dynamics in genomic DNA from in vitro-grown plant species: a SERS assessment
- Author
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Nicolae Leopold, Monica Purcaru, Cristina M. Muntean, Luiza Buimaga-Iarinca, Cristian Morari, and Ioan Bratu
- Subjects
DNA, Plant ,Chrysanthemum ,Chemistry ,Relaxation (NMR) ,Analytical chemistry ,Sequoia ,General Physics and Astronomy ,Interaction energy ,Plants ,Rosa ,Spectrum Analysis, Raman ,Plant Leaves ,symbols.namesake ,genomic DNA ,Molecular dynamics ,chemistry.chemical_compound ,symbols ,Nucleic acid ,Molecule ,Physical and Theoretical Chemistry ,Raman spectroscopy ,Genome, Plant ,DNA - Abstract
In this work the surface-enhanced Raman total half band widths of seven genomic DNAs from leaves of chrysanthemum (Dendranthema grandiflora Ramat.), common sundew (Drosera rotundifolia L.), edelweiss (Leontopodium alpinum Cass), Epilobium hirsutum L., Hypericum richeri ssp. transsilvanicum (Čelak) Ciocârlan, rose (Rosa x hybrida L.) and redwood (Sequoia sempervirens D. Don. Endl.) have been measured. We have shown that surface-enhanced Raman spectroscopy (SERS) can be used to study the fast subpicosecond dynamics of DNA in the proximity of a metallic surface. The dependencies of the total half band widths and the global relaxation times, on the DNA molecular subgroup structure and on the type of genomic DNA, are reported. In our study, the full widths at half-maximum (FWHMs) for the SERS bands of genomic DNAs from different leaf tissues are typically in the wavenumber range from 15 to 55 cm(-1). Besides, it can be observed that molecular relaxation processes studied in this work have a global relaxation time smaller than 0.71 ps and larger than 0.19 ps. A comparison between different ranges of FT-Raman and SERS band parameters, respectively, corresponding to DNA extracted from leaf tissues is given. It is shown that the interaction between DNA and a metallic surface has the potential to lead to a shortening of the global relaxation times, as compared with molecular dynamics in solution. We have found that the surface dynamics of molecular subgroups in plant DNA is, in some cases, about two times faster than the solution dynamics of nucleic acids. This can be rationalized in a qualitative manner by invoking the complex landscape of the interaction energy between the molecule and the silver surface.
- Published
- 2015
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43. Spin-polarized ballistic conduction through correlated Au-NiMnSb-Au heterostructures
- Author
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Liviu Chioncel, W. H. Appelt, Cristian Morari, Andreas Östlin, A. Prinz-Zwick, Ulrich Eckern, and Udo Schwingenschlögl
- Subjects
Materials science ,Strongly Correlated Electrons (cond-mat.str-el) ,Condensed matter physics ,Spin polarization ,Scattering ,Fermi level ,FOS: Physical sciences ,Heterojunction ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,symbols.namesake ,Condensed Matter::Materials Science ,Condensed Matter - Strongly Correlated Electrons ,Ballistic conduction ,0103 physical sciences ,symbols ,Density of states ,ddc:530 ,Density functional theory ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,0210 nano-technology ,Spin (physics) - Abstract
We examine the ballistic conduction through Au-NiMnSb-Au heterostructures consisting of up to four units of NiMnSb in the scattering region. We investigate the dependence of the transmission function computed within the local spin density approximation (LSDA) of the density functional theory (DFT) on the number of half-metallic units in the scattering region. For a single NiMnSb unit the transmission function displays a spin polarization of around 50 % in a window of 1 eV centered around the Fermi level. By increasing the number of layers an almost complete spin polarization of the transmission is obtained in the same energy window. Supplementing the DFT-LSDA calculations with local electronic interactions, of Hubbard-type on the Mn sites, leads to a hybridization between the interface and many-body states. The significant reduction of the spin polarization seen in the density of states is not apparent in the spin-polarization of the conduction electron transmission, which suggests the localized nature of the hybridized interface and many-body induced states., 25 pages, 6 figures
- Published
- 2017
44. Quantitative thermal wave phase imaging of an IR semi-transparent GaAs wafer using IR lock-in thermography
- Author
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M. Streza, Cristian Morari, Michał Pawlak, Karol Strzałkowski, Mihai Chirtoc, Michael Depriester, Conception d’Architectures Moléculaires et Processus Electroniques (CAMPE), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Unité de Dynamique et Structure des Matériaux Moléculaires (UDSMM), Université du Littoral Côte d'Opale (ULCO), Groupe de Recherche en Sciences Pour l'Ingénieur - EA 4694 (GRESPI), Université de Reims Champagne-Ardenne (URCA)-SFR Condorcet, Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Institut de Thermique, Mécanique, Matériaux (ITheMM), Université de Reims Champagne-Ardenne (URCA), Institut de Chimie du CNRS (INC)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Materials science ,Infrared ,Infrared spectroscopy ,02 engineering and technology ,Thermal diffusivity ,01 natural sciences ,7. Clean energy ,[SPI.MAT]Engineering Sciences [physics]/Materials ,010309 optics ,[SPI]Engineering Sciences [physics] ,Optics ,0103 physical sciences ,Thermal ,Wafer ,Instrumentation ,Engineering (miscellaneous) ,ComputingMilieux_MISCELLANEOUS ,[PHYS]Physics [physics] ,[SPI.GCIV.CD]Engineering Sciences [physics]/Civil Engineering/Construction durable ,business.industry ,Applied Mathematics ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,[SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph] ,021001 nanoscience & nanotechnology ,Semiconductor ,Thermography ,[SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic ,Optoelectronics ,Radiometry ,0210 nano-technology ,business ,[SPI.GCIV.EC]Engineering Sciences [physics]/Civil Engineering/Eco-conception - Abstract
International audience; In this paper, the simultaneous measurement of out-of-plane thermal diffusivity and effective infrared absorption coefficient of an IR semi-transparent GaAs wafer using infrared lock-in thermography technique (LIT) is presented. The method relies on analysis of the generated LIT phase images recorded at different modulation frequencies, using the thermal wave model in the transmission configuration. The out-of-plane thermal diffusivity and effective infrared absorption coefficient are estimated from the best fit of the theoretical model to the experimental data. The obtained values are in good agreement with those obtained by supplementary measurement using the modulated photothermal infrared radiometry technique (PTR) in the reflection mode, and also with data reported in the literature. In addition, simple modification of the LIT experiment set up allows one to determinate the in-plane thermal diffusivity of n-GaAs wafer. It was found that in-plane and out-of-plane thermal diffusivities of the GaAs wafer are very close, as expected, within the limit of measurement errors. The results show that the LIT technique in transmission configuration can provide spatial information about both the (effective) infrared absorption coefficient and thermal diffusivity of semiconductor crystals.
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- 2017
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45. DFT study of the trioxotriangulene derivatives in bulk state
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Călin G. Floare, Luiza Buimaga-Iarinca, and Cristian Morari
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symbols.namesake ,Electrode material ,Chemical physics ,Chemistry ,symbols ,General Physics and Astronomy ,Molecule ,Density functional theory ,Electronic structure ,State (functional analysis) ,Physical and Theoretical Chemistry ,van der Waals force ,Atomic physics - Abstract
We present density functional theory investigations on the electronic structure properties for three derivatives of trioxotriangulene that were recently used as electrode materials in Li–ion batteries. We compare the results obtained by standard GGA exchange–correlation functionals with those based on recently developed van der Waals exchange–correlation functionals for the free molecules and bulk structures. This allows us to point out the importance of van der Waals interaction for the stability of the structures as well as the main characteristics of the electronic structures.
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- 2014
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46. Determination of current homogeneity on the electrodes of lead-acid batteries through electrochemical impedance spectroscopy
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Cristian Morari, Adrian Calborean, and Teodora Murariu
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Materials science ,Constant phase element ,General Chemical Engineering ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Dielectric spectroscopy ,Homogeneity (physics) ,Electrode ,Electrochemistry ,Equivalent circuit ,Composite material ,0210 nano-technology ,Lead–acid battery ,Electrical impedance - Abstract
This work explores a qualitative appraisal of lead acid battery electrodes by Electrochemical Impedance Spectroscopy. Lead acid cells behavior has been examined by gathering data of impedance modifications in distinct electrolyte volumes, from a full one to a battery filled at about 20% of the total volume of acid. Since the current between electrodes is inhomogeneous around the collector by varying the quantity of the electrolyte, we have associated numerical values of the elements in the battery equivalent circuit, to the homogeneity of the current in the electrodes. Theoretical considerations dealing with modeling, equivalent circuits and corresponding equations are provided. As a function of the electrolyte quantity, we investigated the dependence of the values for components of the Randle circuit. A particular attention has been devoted to constant phase element (CPE) peculiarities, as this parameter was found essential for a good quality fit over an extended range of batteries. The stability depending on current homogeneity at a certain battery state of charge was analysed in order to assess the effect of electrolyte volumes, and thereby to provide new quality requirements for improvement of lead-acid battery performance.
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- 2019
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47. INFLUENCE OF PLASMA COATED WOVEN FABRICS YARN'S DENSITY ON ELECTROMAGNETIC SHIELDING EFFECTIVENESS.
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Ion Răzvan, RĂDULESCU, Lilioara, SURDU, Emilia, VISILEANU, Răzvan, SCARLAT, Cătălin, CONSTANTIN, Cristian, MORARI, and Bogdana, MITU
- Subjects
ELECTROMAGNETIC shielding ,COATED textiles ,ELECTRONIC equipment ,YARN ,COPPER films ,ELECTROMAGNETIC compatibility - Abstract
Electromagnetic radiation in our environment means hazards for human's health and interference for electronic equipment. One method of protection according to electromagnetic compatibility is shielding. Conductive textiles represent a modern solution for electromagnetic shielding, due to their specific properties like lightweight, flexibility, mechanical resistance and 3D - shape ability. There are mainly two methods for imparting electric conductive properties on textile materials: insertion of conductive yarns within the fabric structure and coating of the fabric surface with conductive raw materials. This paper presents textile EM shields achieved by combining these methods: woven fabric structures with inserted silver yarns in warp and weft direction with various fabric densities were designed and manufactured and afterwards coated by magnetron plasma with a copper thin film. Electromagnetic Shielding Effectiveness (EMSE) measurements were conducted on these fabrics in the frequency range of 0.1-1000 MHz. Values of EMSE reached 40-55 dB. The main aim of the paper is to show that fabrics with a low yarn density have a better gain of EMSE values after plasma coating with copper. This fact may be explained by an interpenetration of the copper films from one side to the other side within the woven fabric structure for low yarn densities and formation of electrically conductive paths. [ABSTRACT FROM AUTHOR]
- Published
- 2020
48. Effect of Conformational Symmetry upon the Formation of Cysteine Clusters on the Au(110)-(1 × 1) Surface: A First-Principles Study
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Cristian Morari and Luiza Buimaga-Iarinca
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Chemistry ,Nucleation ,Protonation ,Symmetry (physics) ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Crystallography ,General Energy ,Adsorption ,Group (periodic table) ,Molecule ,Physical and Theoretical Chemistry ,Conformational isomerism ,Cysteine - Abstract
The physical properties of cysteine clusters formed on the Au(110)-(1 × 1) surface are investigated by means of density-functional theory. We take into account the clusters formed from three types of rotational conformers of cysteine; for each structure we investigate the protonated and unprotonated forms. Our investigations are based on three different geometrical models for the surface–adsorbate system, allowing us to describe the formation of new nucleation centers on the surface as well as the properties of long chains of cysteine molecules adsorbed on the Au(110)-(1 × 1) surface. We point out significant differences between the relaxed structures formed by each conformer as well as the specific physicochemical properties leading to formation of new nucleation centers compared with those of already formed large cysteine structures. In particular, we emphasize the role of the NH2 group of cysteine in these processes, by correlating our data with its relative position with respect to the gold surface.
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- 2013
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49. Double Amino Functionalized Ag Nanoparticles as SERS Tags in Raman Diagnostic
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Alexandra Falamas, Monica M. Venter, Simona Cinta Pinzaru, Cristian Morari, and Cristina Dehelean
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Near-infrared spectroscopy ,Nanoparticle ,General Chemistry ,Photochemistry ,FT-SERS ,SERS label ,cresyl violet ,amino functionalized-Ag nanoparticles ,Silver nanoparticle ,symbols.namesake ,Cresyl violet ,chemistry.chemical_compound ,chemistry ,Chemisorption ,symbols ,Spectroscopy ,Raman spectroscopy ,Raman scattering - Abstract
Surface enhanced Raman scattering (SERS) effect is currently exploited as the basis of a new type of optical labels for in vivo investigation of the tissues, especially for early medical diagnostic. Silver colloidal nanoparticles decorated with chemisorbed cresyl violet molecular species could act as hybrid SERS labels. Their Raman scattering properties have been characterized here using different SERS techniques, and probing different excitation wavelengths, even in the near infrared. Obtaining FT-SERS signal of cresyl violet is of particular importance for applying FT-Raman spectroscopy to the tissues or cells, in providing sensitive information in the close vicinity of the SERS label incubated into the biological sample. Furthermore, upon chemisorption on the silver nanoparticles, cresyl violet molecular orientation provided both amino functional groups free of interaction with the silver, resulting double amino-functionalized Ag nanoparticles suitable for DNA tagging. SERS tests of melanoma induced in mouse using CV-Ag SERS label suggested the possibility to setup the tissue labeling procedure for skin cancer monitoring.(doi: 10.5562/cca2067)
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- 2013
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50. Charge and spin transport in single and packed ruthenium-terpyridine molecular devices: Insight from first-principles calculations
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Ivan Rungger, Cristian Morari, Gian-Marco Rignanese, Luiza Buimaga-Iarinca, Stefano Sanvito, and Sorin Melinte
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Multidisciplinary ,Materials science ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Electrical contacts ,Article ,0104 chemical sciences ,Ruthenium ,chemistry.chemical_compound ,Magnetization ,chemistry ,Chemical physics ,Electrode ,Molecule ,Terpyridine ,0210 nano-technology ,Scaling ,Spin-½ - Abstract
Using first-principles calculations, we study the electronic and transport properties of rutheniumterpyridine molecules sandwiched between two Au(111) electrodes. We analyse both single and packed molecular devices, more amenable to scaling and realistic integration approaches. The devices display all together robust negative differential resistance features at low bias voltages. Remarkably, the electrical control of the spin transport in the studied systems implies a subtle distribution of the magnetisation density within the biased devices and highlights the key role of the Au(111) electrical contacts.
- Published
- 2016
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