Search

The relationship between China and Pakistan has a long history, and the two countries have maintained a long-term cooperative partnership. Under this relationship, fruitful cultural exchanges have taken place, although occasional cultural conflicts have occurred. Based on the foundation of long-term cooperation, conflicts in cultural exchanges have been effectively resolved through mutual visits, promoting deeper understanding and trust between the two sides. Therefore, it can be said that cultural exchange between China and Pakistan is an important tool for adjusting cultural conflicts, promoting diplomatic relations, and bridging the gap between the two countries. This article reviews and examines the history of cultural exchanges between China and Pakistan and proposes a conflict adjustment framework based on "respect-understanding-communication-trust." Specific measures are also proposed, such as "establishing smooth cultural communication channels, improving conflict resolution mechanisms, deepening cultural exchange projects, and strengthening joint research projects" to adjust cultural conflicts and promote deeper cultural exchanges between the two countries.

Graphene is a unique nanocarbon nanostructure, which has been frequently used to form nanocomposites. Green-synthesized graphene has been focused due to environmentally friendly requirements in recent technological sectors. A very important application of green-synthesized graphene-based nanocomposite has been observed in energy storage devices. This state-of-the-art review highlights design, features, and advanced functions of polymer/green-synthesized graphene nanocomposites and their utility in supercapacitor components. Green graphene-derived nanocomposites brought about numerous revolutions in high-performance supercapacitors. The structural diversity of conjugated polymer and green graphene-based nanocomposites has facilitated the charge transportation/storage capacity, specific capacitance, capacitance retention, cyclability, and durability of supercapacitor electrodes. Moreover, the green method, graphene functionality, dispersion, and matrix–nanofiller interactions have affected supercapacitance properties and performance. Future research on innovative polymer and green graphene-derived nanocomposites may overcome design/performance-related challenging factors for technical usages.

Semiconductor Silicon quantum dots (SiQDs) and magnetic nanomaterials have been studied extensively for their variety of applications. We have presented a new method for the preparation of Magnetic Silicon Quantum Dots (Fe3O4/SiQDs) heterostructure nanocomposites. These nanocomposites are fluorescent, have excellent magnetic properties as well as high photocatalytic activity. Magnetic nanoparticles-semiconductor nanocomposites served as an effective recoverable photocatalyst for melamine degradation. In addition, due to their easy magnetic separation, these nanocomposites showed optimum catalytic activity for 15 cycles of usage.

Fuel cell efficiency can be improved by using progressive electrodes and electrolytes. Green nanomaterials and green technologies have been explored for the manufacturing of high-performance electrode and electrolyte materials for fuel cells. Platinum-based electrodes have been replaced with green materials and nanocomposites using green fabrication approaches to attain environmentally friendly fuel cells. In this regard, ecological and sustainable electrode- and electrolyte-based membrane electrode assemblies have also been designed. Moreover, green nanocomposites have been applied to form the fuel cell electrolyte membranes. Among fuel cells, microbial fuel cells have gained research attention for the incorporation of green and sustainable materials. Hence, this review essentially focuses on the potential of green nanocomposites as fuel cell electrode and electrolyte materials and application of green synthesis techniques to attain these materials. The design of and interactions with nanocomposites have led to synergistic effects on the morphology, impedance, resistance, power density, current density, electrochemical features, proton conductivity, and overall efficiency. Moreover, we deliberate the future significance and challenges of the application of green nanocomposites in electrodes and electrolytes to attain efficient fuel cells.

One important application of polymer/graphene nanocomposites is in membrane technology. In this context, promising polymer/graphene nanocomposites have been developed and applied in the production of high-performance membranes. This review basically highlights the designs, properties, and use of polymer/graphene nanocomposite membranes in the field of gas separation and purification. Various polymer matrices (polysulfone, poly(dimethylsiloxane), poly(methyl methacrylate), polyimide, etc.), have been reinforced with graphene to develop nanocomposite membranes. Various facile strategies, such as solution casting, phase separation, infiltration, self-assembly, etc., have been employed in the design of gas separation polymer/graphene nanocomposite membranes. The inclusion of graphene in polymeric membranes affects their morphology, physical properties, gas permeability, selectivity, and separation processes. Furthermore, the final membrane properties are affected by the nanofiller content, modification, dispersion, and processing conditions. Moreover, the development of polymer/graphene nanofibrous membranes has introduced novelty in the field of gas separation membranes. These high-performance membranes have the potential to overcome challenges arising from gas separation conditions. Hence, this overview provides up-to-date coverage of advances in polymer/graphene nanocomposite membranes, especially for gas separation applications. The separation processes of polymer/graphene nanocomposite membranes (in parting gases) are dependent upon variations in the structural design and processing techniques used. Current challenges and future opportunities related to polymer/graphene nanocomposite membranes are also discussed.

In the present work, we propose the synthesis of novel nicotinamide subsituted phthlocyanine photosensitizer (PS) and characterized by FTIR, UV–visible, H-NMR and MALDI Toff spectroscopy. Nicotinamide plays a vital rule in the central nervous system and its potential as a therapeutic for neurodegenerative disease. Nicotinamide substituted PS (3) efficiently produced ROS via type-1 process as measured by DCF assay. We observed that our PS after red light illumination (22 J/cm2) killed gram positive S. aureus upto 3 log reduction. Furher the addition of Potassium Iodide (100 mM) significantly potentiated PS at lower concentrations and enhanced the bacterial killing upto 6 log reduction against the S. aureus. We further found that the synergistic effect of PS and KI also eradicated the gram negative E. coli strain at lower concentraion of PS and found to killed E. coli upto 5 log reduction under the red light illumination at 22 J/cm2 of light dose. The conjugation of such biologically important form of vitamin B3 with PS would be a great addition and could pav the way for the novel photodynamic agent in the treatement of cancer and infectious diseases. A new symmetrical Nicotinamide tetrasubstituted zinc phthalocyanine (3) was synthesized. Upon addition of potassium Iodide with PS, the PS exhibited significant photodynamic activity with 5-6 logs reduction in bacterial load was achieved.

The amorphous structural study of silicon carbide nanowires (SiC-NWs) has drawn strenuous attention in recent years due to their worthwhile properties for wide applications, chiefly in optoelectronics. The facile transformation of crystalline SiC-NWs to amorphous defective SiC-NWs is a challenging task for their broad-scale applications. Herein, we report a fantastic strategy (by applying a 5UDH Pelletron accelerator, located at the National Centre for Physics, Islamabad, Pakistan) for Cu ion implantation (fixed at 10 MeV) on the crystalline SiC-NWs to incorporate them into an amorphous structure. For the defects study, various dose rates of Cu+ ion ranging from 5 × 1015 ions/cm2 to 5 × 1016 ions/cm2 were bombarded on SiC-NWs, and a complete transmutation to the amorphous structure of SiC-NWs under a shelling dose of 8 × 1016 ions/cm2 was observed. This work will provide a better avenue for the structural deformation blueprints of the next-generation nanomaterials. Amorphous structural transformation is explained by collision cascade effects phenomena.

The effect of 5 MeV Cu++ ions irradiation on structural and optical properties of Anatase TiO2 nanoparticles (TiO2-NPs) is investigated. For this purpose, TiO2-NPs are irradiated with different Cu++ ions fluences, ranging from 1 × 1015 to 1 × 1016 ions/cm2 at room temperature. XRD results confirm the Ti3O7 phase appear at the dose of 5 × 1015 ions/cm2 and peak intensity of Ti3O7 phase gradually increases with an increase of Cu++ ions irradiation dose. At the dose of 1 × 1016 ions/cm2 TiO2 Anatase phase were transformed to Rutile phase. Same observations are confirmed from Raman spectroscopy. High resolution transmission electron microscopy (HRTEM) reveals that morphology converted into wavy shape and crystal structure detrioted with increase Cu ion irradiation dose to form vacancy loops and interstitial loops. Scanning electron microscopy (SEM) shows that TiO2-NPs have been fused to form a cluster of nanoparticles at high Cu ion beam dose, while bandgap of TiO2-NPs reduces from 3.19 eV to 2.96 eV as a function of Cu++ irradiation fluence. These phase transformations and crystal damage are the responsible for optical bandgap reduction. The mechanism for the currently observed phase transformation of TiO2 and coalescence of TiO2-NPs are discussed in term of thermal spikes model. Keywords: TiO2 nanoparticles, Cu++ irradiation, Rutile phase, Coalescence of NPs, Bandgap engineering

The development of high dielectric loss and magnetic loss for radar absorbing material is a long-term pursuing and under a close scrutiny. Most of the researches have been focused on exploring absorber materials with good absorption performance and at the same time with a good electrical conductivity. To develop a new absorber material will also have significant impacts on boosting the dielectric loss and magnetic loss. Herein, 3D spherical NiCo2S4 (NCS)-based composite has been fabricated via a mild, simple and useful hydrothermal strategy and the electromagnetic wave absorbing properties have been investigated through comparison among NCS, acidified carbon nanotubes (a-CNT)/NCS, reduced graphene oxide (r-GO)/NCS and r-GO/a-CNT/NCS. The experimental results show that the optimal concentration of NiSO4·6H2O to synthesize the composites is 6 M. Furthermore, the frequency bandwidth has been broadened and the maximum absorption peaks have been increased after adding the modified agent. The maximum frequency bandwidth of r-GO/a-CNT/NCS is 5.1 GHz below −5 dB and 2.7 GHz below −10 dB respectively, the maximum absorption peak is −35.8 dB at 8.1 GHz.

To improve the mechanical properties and oxidation resistance of short carbon fiber reinforced silicon carbide matrix composites, carbon nanotubes (CNTs) were grown in-situ on carbon fiber surfaces through continuous CVD, a small amount of phenolic formaldehyde (PF) was added to the matrix to densify the composite and interlock the fiber and the matrix. The CNTs-Cf/PF/SiC composite was fabricated by combining pre-casting and hot-pressing. Microstructural analyses revealed that CNTs were successfully grown on carbon fiber surfaces with entangled structures, while PF presented cobweb-like structure which tightly bonded the fiber and the matrix. Compared with CNTs-Cf/SiC and Cf/SiC, the flexural strength of CNTs-Cf/PF/SiC increased by 15.27% and 51.95%. After heat treatment, the weight loss of CNTs-Cf/PF/SiC reached 21.05%, and 31.9% of flexural strength retained after 15 thermal shock cycles at 1400 °C. These enhanced properties were indicative of its enormous potential to replace traditional Cf/SiC composite.

In this work, reaction bonded silicon carbide (RBSC) brake composites reinforced by chopped carbon fibers (CCFs) were fabricated by pre-liquid dispersion (PLD), low-temperature compression molding (LTCM) and subsequent densification by liquid silicon infiltration (LSI). The effects of the CCF fraction and PLD process on microstructure, phase composition, compression strength, shear strength and tribological performance of the brake composites were evaluated in detail. Our results showed that the distribution of CCF within the brake composites can be improved substantially through the treatment of PLD process, leading to the lowest open porosity of 9.63% and highest buck density of 1.87 g/cm3 comparing to the composites without PLD. Meanwhile, due to the augment of the interfacial area between the CCF and matrix, the as-prepared brake composite with 20 vol% CCF showed a compression strength as high as 157.55 MPa and shear strength of 22.14 MPa. Moreover, after further graphitization, a highly reliable RBSC brake composite with suitable average friction coefficient (0.427) for braking was obtained via the synergistic effects of lubrication of formed graphite and grain-abrasion by SiC grains in spite of a relatively high mass wear rate. These results show that the CCF reinforced RBSC brake composite is a promising candidate for high performance and low-cost friction composite for the application in brake pads.

In the present work, we propose the synthesis of novel nicotinamide subsituted phthlocyanine photosensitizer (PS) and characterized by FTIR, UV-visible, H-NMR and MALDI Toff spectroscopy. Nicotinamide plays a vital rule in the central nervous system and its potential as a therapeutic for neurodegenerative disease. Nicotinamide substituted PS (3) efficiently produced ROS via type-1 process as measured by DCF assay. We observed that our PS after red light illumination (22 J/cm

Recently, copper sulfide (CuS) quite arouses researchers' interest due to its high theoretical capacity and excellent electroconductivity. However, poor cycling stability seriously limited the application in supercapacitors. In addition to the improvement of cycling performance, it is also a challenge to develop electrode materials with energy density. Herein, RGO/CuS composite is prepared successfully by solvothermal reaction methods. By the observation using FESEM and TEM, CuS microstructure displays regular and tiny nanoparticles, which are supported by RGO sheets. After the electrochemical measurements, RGO/CuS composite exhibits a maximum specific capacitance of 946 F g−1 at 10 mV s−1 and 906 F g−1 at 1 A g−1, respectively. The excellent cycling stability is also achieved and it maintains 89% retention after 5000 cycles at 5 A g−1. RGO/CuS composite also possesses high energy density of 105.6 W h kg−1 at the power density of 2.5 kW kg−1, which indicates that RGO/CuS composite has a bright future as electrode materials for supercapacitors.

3D printing is a fast-emerging technology, and a shape is fabricated using layer-by-layer deposition of a material in a bottom-up manufacturing operation. Here a porous nickel/polyaniline nanocages multiscale supercapacitor synthesized using 3D printing technology is fabricated. The porous structure of iron-nickel and polyaniline nanocages can increase the specific surface area which lead to enhance the specific capacitance. 3D printing technology is presented in energy devices to accurately fabricate the delicate structure.

Porous copper (Cu) films were facilely and greenly fabricated by low-current electrical field-induced assembly of ~ 3 nm Cu nanoparticles (NPs) in several minutes using generated hydrogen bubbles as dynamic negative templates. The porous films had open three-dimensionally (3D) interconnected nanopores and uniform pore size distribution and exhibited a hierarchical structure composed of supraparticles that were further composed of the Cu NPs. Lattice-to-lattice connectivity in the self-assembly of the NPs in the 3D structures enables fast charge transport. The structure/morphology of the porous Cu materials can be tuned by adjusting the concentration of the additives, applied potential/current densities and assembly time. A growth mechanism of the porous films was reasonably proposed for the field-induced assembly of the Cu NPs. The porous Cu film-supported Si electrode showed high capacity of 1173 mAh g−1 and retention rate of 87% after 10 cycles at 1 C. Our research sheds a light on preparing 3D nanoporous structures especially for suitable electrodes in electrochemical energy storage devices.

High temperature lithium-sulfur batteries are seldom investigated due in part to the lack of mechanical robust separators and the more serious parasitic polysulfide shuttle effects at elevated temperature. Here, we for the first time present high performance lithium-sulfur cells that can be cycled at elevated temperature of 100 °C via designing asymmetric functionalized polyimide-based separators using a facile and scalable blade-casting method. In this sandwich configuration, polyimide nonwovens act as electrochemically and mechanically robust skeleton while Super-P nanoparticles coating and poly (ethylene oxide)-integrated-lithium lanthanum zirconium oxide coating render additional functions of immobilizing polysulfides and inhibiting lithium dendrite growth, respectively. By virtue of the multifarious functions of the modified polyimide-based separator, a high specific capacity of 1474.3 mAh g−1 without severe over-charge behavior is also firstly demonstrated at a higher temperature of 100 °C. Additionally, Li-S cells using the modified polyimide -based separator deliver excellent cycling stability (only 0.2% capacity decay cycle−1 on average exceeding 200 cycles at 80 °C) at a relatively high rate of 5C. The experimental results validate the pivotal role of newly designed separators for high performance lithium-sulfur chemistry especially at elevated temperature.

Recently, ceramic matrix composites reinforced by short carbon fibers (CFs) attracted increasing attentions. To further improve mechanical properties and oxidation resistances, CFs were subjected to oxidation and acidification followed by sol-gel dip-coating to deposit ZrO2 on their surfaces. ZrO2-Cf/SiC composites were fabricated by joint hot compression molding and sintering, compared to Cf/SiC and SiC prepared by the same method. Microstructural analyses indicated that ZrO2 coatings were successfully deposited on CF surfaces, formed strong bonding and interfaces between CF and the matrix. Meanwhile, CFs were found uniformly distributed in SiC matrix with random orientations. Flexural curves of ZrO2-Cf/SiC and Cf/SiC revealed the presence of “false plasticity” regions after sharp drops, which were quite different from brittle flexural behavior of SiC ceramic. Compression strength of the three samples showed step-up growth. ZrO2-Cf/SiC exhibited the highest value, indicating the introduction of CFs and ZrO2 coatings do have great influence on mechanical performances. After heat treatment, ZrO2-Cf/SiC exhibited better oxidation resistance than Cf/SiC, with weight loss ratios estimated to − 3.76% and − 6.43%, respectively. These improved properties indicated that ZrO2-Cf/SiC would be excellent alternatives to other existence materials under ultra-high temperature environments.

Diamond nanoparticles (DNPs) have been strongly integrated into diverse technological applications due to its nano-size, good chemical stability, super hardness, thermal conductivity and biocompatibility. Agglomeration and non-uniform distribution of DNPs in different matrices are the two main concern problems which limits its wide spread applications. Herein, our present research work demonstrated a comparative study of ball milling and acid treatments of functionalization DNPs through surface modification with carboxylic acid and amid functional groups. The dispersion measurement showed that ball mill treated DNPs is uniform and homogeneously dispersed in dimethyl-sulfoxide (DMSO) rather than as-received and acid treated DNPs. Furthermore, the use of various weight percentages of acid and ball mill functionalized DNPs in epoxy resin showed that 0.2 wt% is the optimum amount which revealed the highest ultimate tensile strength, flexural strength, Young's modulus and energy to break values of the nanocomposites. The comparative analysis showed that ball mill treatment of functionalization significantly enhanced the mechanical performances of epoxy resin more effectively than acid treatment thus demonstrated the importance of ball milling technique.

In this work, a long-life and high-performance electrode material is successfully fabricated by the incorporation of carbon nanotube (CNT) with different length using chemical vapor deposition (CVD) on a hierarchically three dimensional (3D) carbon foam (CF), which is obtained from the mesophase pitch. The morphology, composition, and electrochemical performance of the as-prepared composites are characterized using the scanning electron microscope (SEM), Raman spectroscopy, X-ray diffraction (XRD) patterns, cyclic voltammetry, and galvanostatic charge/discharge cycling techniques. Characterizations suggest that this resultant CF/CNT-50 electrode material has a good cycling stability with capacitance retention of 96.5% even after 10000 cycles. Moreover, it shows a high mass capacitance of 227.5 F/g based on the resultant electrode materials, higher energy density of 28 Wh kg−1 and power density of 3700 W kg−1 at a current density 2 A g−1 and also excellent charge/discharge rate. These measured charge storage properties make the proposed hybrid materials excellent electrode material candidates for high performance supercapacitors.

Coiled amorphous carbon nanotube (CACNT) array was prepared by chemical vapor deposition method. The experimental results indicated that the length of as-prepared CACNT array was about 30 μm. The electromagnetic wave absorbing properties were studied through comparison among CACNTs, CACNT-La(NO 3 ) 3 , CACNT-(Fe, Co, Ni) and CACNT-reduced graphene oxide (RGO). The experimental results showed the maximum frequency bandwidth of CACNT-(Fe, Co, Ni) was 6.4 GHz below −5 dB and 2.3 GHz below −10 dB separately. Compared to the pure CACNTs, all the frequency bandwidth had been broaden after adding the modified agent. Meanwhile, the additive of rare earth ions La 3+ could effectively increase the maximum absorption peak (−17.94 dB at 8.96 GHz).

Pt nanoparticles decorated with rose-like Bi2O2CO3 configurations were synthesized via a simple photoreduction method at room temperature. The structure, morphology, optical and electronic properties, and photocatalytic performance of the as-prepared materials were characterized. Compared to pure Bi2O2CO3, the Pt/Bi2O2CO3 photocatalysts show better performance in decomposing RhB, BPA and OTC under visible light (λ > 420 nm). The enhanced photocatalytic activity of Pt/Bi2O2CO3 could be attributed to the modification in light absorption (λ > 420 nm) charge migration and the separation of photo-generated electrons (e−) and holes (h+). Free radical trapping experiments demonstrated that the main active species of the catalytic reaction are different in decomposing RhB and BPA.

C f /Ti 3 SiC 2 -SiC composites with different content of short carbon fibers were fabricated by the combination of compression molding and pressureless sintering. Microstructure and mechanical behavior of the composites were studied to evaluate the comprehensive performance of the material. In comparison, composites without carbon fibers were also fabricated in the same way. The results indicate that Ti 3 SiC 2 phases were synthesized in each cases and exhibit typical laminated structure with smooth surface. With the increase of carbon fiber content, composites turn from brittle to toughness, and show obvious elastic and no-linear regions on the force-displacement curve. Moreover, composite with 30% (volume fraction) carbon fiber shows the highest flexural strength (284.03 MPa), open porosity (15.78%), and lowest density (2.37 g cm −3 ). There were chemical reactions occurred between carbon fibers and matrix which formed strong covalent bonds and interfaces. The micrographs also reveal that fiber bridging and pulling-out are the most important reinforcement mechanisms which contribute to the mechanical properties of the composites.

This work presents a simple approach to produce controlled mullite whisker network structure. Mullite whisker networks were facilely prepared by direct sintering of coal fly ash, bauxite and kaolin in BaCO3-potash feldspar-pyrolusite-talcum catalytic system at 1350 °C. Controlled mullite whiskers were obtained with about 200 nm in diameter and 3 μm in length by controlling the rate of Al2O3 diffusion through feldspar addition in catalytic system. Morphology evolution process and growth characteristics of mullite whisker networks were further investigated using scanning electronic microscope (SEM) and their possible fabrication mechanism were also investigated. The optimum mullite whisker network structural material exhibits some attractive properties such as high strength (199.89 MPa), low density (1.51 g cm−3) and low acid solubility (2.63 wt%). These results demonstrate an effective method to prepare large-scale mullite whisker network with potential applications in producing ceramic proppants.

Multi wall carbon nanotubes (MWCNTs) and diamond nanoparticles (DNPs) reinforced carbon foam composites were prepared by the direct pyrolysis of MWCNTs, DNPs and mesophase coal tar pitch mixture. The effect of additive amounts on the microstructure and properties of carbon foams were studied. Significant impacts on the microstructure of carbon foams were observed after the incorporation of additive amounts. Whereas, the additive behavior of MWCNTs and DNPs were further investigated in terms of adsorption, mechanical and thermal properties. The results shows that the nickel (Ni) and cadmium (Cd) metal ions adsorption tendency increases with the increase of MWCNTs and DNPs contents. The maximum adsorption percentage of 84.6 and 86.9% was observed for carbon foam containing 2 wt% MWCNT-DNPs loading for Ni and Cd ions respectively. Furthermore, the compressive strength and thermal conductivity of the carbon foams were enhanced with the increase of additives amounts. Maximum improvement of 19.22 MPa in the compressive strength and 37.46 W/m K at 800 °C of thermal conductivity was revealed by carbon foam composite containing 4 wt% MWCNT-DNPs additive amounts.

We applied acid treatment for the surface modification of detonation nanodiamond (DND) powder by minimizing their surface energy to overcome agglomeration and improve dispersion of DNDs. Different concentrations of acid modified DND in 828 epoxy matrix were fabricated to check their mechanical and electromagnetic properties. Mechanical properties were checked in terms of ultimate tensile strength (UTS), toughness, energy to break, percent strain break and Young's modulus while electromagnetic shielding properties were studied in frequency range of 11–17 GHz. To analyze electrical and magnetic properties of the nanocomposites, relative permittivity and permeability tests were performed. Excellent interactions among acid modified DND and epoxy resin was observed due to carboxyl and hydroxyl functional groups that results in the formation of efficient load transfer interface, which in turn enhance the mechanical and electromagnetic properties of epoxy nanocomposites. During investigation it was observed that mechanical properties and relative permittivity showed enhancements when, 0.2 wt% acid modified DND were used as a nano-filler, while on further increment of modified DND these properties start decreasing. Unlike this, the relative permeability, reflection and transmission loss values were increased with the increase of acid modified DND content.

The pursuing aim of high reflection loss and broad frequency bandwidth for electromagnetic wave (EMW) absorbing materials is a long-term task and under a close scrutiny. To construct rational microstructures for the absorber have significant impacts on increasing reflection loss and broadening frequency bandwidth. Herein, we presented a sandwich microstructured expand graphite (EG)/BaFe12O19 (BF) nanocomposite successfully prepared by in-situ sol-gel auto-combustion method. The experimental results showed that EG/BF nanocomposite has better EMW absorbing performance than pure EG and BF, the sandwich microstructured EG/BF connected with carbon nanotubes (CNTs) could further improve the electromagnetic performance effectively. The obtained CNT/EG/BF nanocomposite exhibited a saturation magnetization of 26.5 emu g−1 at room temperature and an excellent EMW absorbing performance. The maximum reflection loss of the sandwich microstructured CNT/EG/BF composites with a thickness of 1 mm was up to −45.8 dB and the frequency bandwidth below −10 dB could reach to 4.2 GHz within the frequency range of 2–18 GHz. The research results indicated that the prepared nanocomposite showed great potential as a new type of microwave absorbing material.

Homogeneous amorphous carbon nanotube (ACNT) networks have been synthesized using floating catalyst chemical vapor deposition method on a 3D graphene aerogel (GA)/ BaFe12O19 (BF) nanocomposite which was prepared by a self-propagating combustion process. The as-synthesized ACNT/GA/BF nanocomposite with 3D network structures could be directly used as a good absorber material for electromagnetic wave absorption. The experimental results indicated that the minimum reflection loss of ACNT/GA/BF composite with a thickness of 2 mm was −18.35 dB at 10.64 GHz in the frequency range of 2–18 GHz. The frequency bandwidth of the reflection loss below −10 dB was 3.32 GHz and below −5 dB was 6.24 GHz, respectively. The 3D graphene aerogel structures which composed of dense interlined tubes and amorphous structure bearing quantities of dihedral angles could consume the incident waves through multiple reflection and scattering inside the 3D web structures. The interlinked ACNTs have both the virtues of amorphous CNTs (multiple reflection inside the wall) and crystalline CNTs (high conductivity), consuming the electromagnetic wave as resistance heat. ACNT/GA/BF composite has a good electromagnetic wave absorption performance.

A novel silicon core/amorphous carbon nanotube (ACNT) shell composite that can be used as lithium-ion batteries anode material was in-situ synthesized in the chemical vapor deposition (CVD) growth process. The hypothesized core/shell structure was evidenced by SEM/TEM/XRD, suggesting that the ACNTs composed of carbon clusters with short-range order and long-range disorder were successfully deposited onto the surface of the silicon particles. This Si/ACNT composite delivered a high capacity of 1496 mAh g −1 at a current density of 100 mA g −1 , and a superior cycling stability with 80% capacity retention after 300 cycles. This observed specific capacity improvement of Si/ACNT composite is likely attributed to the formed three-dimensional conductive networks between silicon particles and interwoven ACNTs in the composite.

In this work, reduced graphene oxide (RGO) - carbon nanotubes (CNT) grown on carbon fiber (CF) is fabricated by a combination of electrophoretic deposition (EPD) and chemical vapor deposition (CVD). Firstly, CF-GO composite is prepared via EPD. Secondly, the CF-RGO-CNT hybrid is obtained by floating catalyst chemical vapor deposition method for synthesizing CNT on the CF-RGO substrate. The as-prepared three-dimensional (3D) hierarchical hybrid shows strong mechanical stability and high flexibility at various bending angles. Furthermore, the hybrid is characterized by scanning electron microscope, X-ray Diffraction and Raman spectroscopy, and its supercapacitor properties are also tested. The electrochemical measurements display a higher specific capacitance of 203 F g−1, 4 times higher than that of pure CF. Importantly, the hybrid shows high electrochemical stability at various bending angles, and can be directly served as flexible electrode with binder-free for high-performance supercapacitors. All these attractive results indicate that the as-prepared 3D hybrid is a promising candidate for flexible supercapacitor applications.

Aligned amorphous carbon nanotube (AACNT)/BaFe12O19 nanorod (BNR) composite was prepared by chemical vapor deposition and ball-milling methods. Raman and XRD tests were performed to investigate the microstructures, and the microwave absorbing properties of the as prepared composite were characterized using a vector network analyzer. The experimental results indicated that the mean length of as-prepared ACNT arrays was about 24 μm and the average length of BNRs were about 50 nm. The maximum absorbing peak of AACNTs/BNR composite is −21.5 dB at the frequency of 9.3 GHz. The frequency bandwidth of the reflectivity loss below −10 dB is about 2.5 GHz. AACNTs have both features of amorphous CNTs which have multiple-reflective path inside the tube-wall and crystalline CNTs which have high conductivity.

High strength lightweight mullite whisker network reinforced ceramic materials was successfully prepared by firing a bauxite - kaolin - coal fly ash mixture with additions of varying mixtures of feldspar - talcum - BaCO 3 - pyrolusite. The mullite whisker network exhibits a unique architecture in which thin mullite crystals layers with anisotropic properties and well controlled crystal size were interweaved with one another. The effects of pyrolusite content on morphologies and properties of resultant ceramic materials were investigated. The phase compositions and microstructures of several samples were investigated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The flexural strength and acid solubility of ceramic materials as functions of sintering temperature were systematically investigated by measuring the flexural strength and acid solubility at different sintering temperature, respectively. The resulting mullite whisker network structure ceramic materials showed optimum performance at sintering temperature around 1390 °C when the content of pyrolusite equals to 6 wt%, such as high strength (190.10 MPa), low density (1.48 g cm −3 ) and low acid solubility (2.55 wt%). The approach opens new opportunities for the sintered ceramic as a proppant material since the ceramic system displays low acid solubility and good flexural strength.

The development of more advanced and environmentally friendly energy storage devices is an urgent request to meet future societal and environmental needs. Supercapacitor is one of the most promising electrochemical energy storage devices owning to its long cycle life, high dynamic propagation, quickly response and low maintenance cost compared to the traditional batteries and capacitors. However, their energy density is far less batteries, which limits their application in energy storage. In order to break through the limitation, exploring novel electrode materials with both high energy densities and power densities is extremely urgent. At present, it is a hot topic to produce composite electrode materials with synergistic effect. Graphene, a one-atom-thick two dimensional single layer of sp2-bonded carbon, owning to its unique structural properties, has exhibited many advantages, such as extraordinarily high electrical and thermal conductivity, great mechanical strength and high surface area, making it a potential candidate for applications in energy storage field. Therefore, graphene based composite materials have been utilized in various practical applications, including energy storage and conversion, transparent conducting films, chemical sensors, and actuators, etc. Given the extraordinary properties of graphene, such as the low mass density, good compatibility, highly conductive, large specific surface area and excellent flexibility, it is considered as one of the most suitable substrate materials for preparing supercapacitor electrodes. In recent years, graphene composites as supercapacitor electrode material have been widely investigated. Here, three- dimensional (3D) graphene/carbon nanotube (CNT) nanocomposites were prepared by in-situ compound method using as-synthesized graphene as matrix, which prepared by chemical vapor deposition (CVD). Firstly, graphene was prepared on Ni foam by CVD method using CH4 as carbon sources and H2/Ar as buffer gas at 850°C. Then a solution carbon source was obtained by ultrasonic vibration using a mixture solution of ferrocene and dimethylbenzenes. Finally, 3D graphene/CNT nanocomposite was synthesized by CVD method using Ni foam deposited graphene as supporter substrate at 750°C for 30 min. The morphology and microstructure of the resulting samples were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the electrochemical capacitive performance of the samples were investigated using CHI 660D chemical workstation to analyze the cyclic voltammetry and AC impedance. The results indicated that large amounts of graphenes had been formed on the Ni foam and 3D graphene/CNT nanocomposites also had been synthesized. The 3D lamellar structures between graphenes formed in the synthesis process could densely upload active substance, which was very different in structure and performance with individual graphene. The cyclic voltammetry (CV) curves of 3D graphene/CNT composite exhibited that the electrochemical capacitive performance has good reversibility. The Nyquist plots also displayed that the 3D graphene/CNT composite has excellent performance of electric charge transportation and double layer capacitance. The electrochemical measurements indicated that the maximum specific capacitance of 3D graphene/CNT composite, as the supercapacitor electrode material, exhibited a maximum specific capacitance of 289.8 F/g using 1.5 mol/L Li2SO4 as the electrolyte in the system and also showed excellent high-capacity and cycling stability. The specific capacitance of the 3D graphene/CNT composite remains 92% after 2000 cycles.

This paper describes the characterization of a three-dimensional (3D) reduced graphene oxide (RGO)-carbon nanotube (CNT)-polyaniline (PANI) hybrid fabricated by combining electrophoretic deposition (EPD) and floating catalyst chemical vapor deposition (FCCVD), followed by in - situ anodic electrochemical polymerization (AEP). Firstly, the RGO-CNT is prepared by combining EPD of GO onto nickel foams (NF) and then growth of uniformly aligned CNT on the surface of RGO via FCCVD. Secondly, the 3D RGO-CNT-PANI hybrid is successfully fabricated by in situ AEP of aniline monomers onto the surface of the RGO-CNT. The structures and morphologies of the hybrid have been characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X - ray diffraction (XRD) and X-ray photoelectron spectrometer (XPS). Electrochemical properties are studied by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. The results reveal that the as-prepared hybrid based on the two - electrode system displays very high specific capacitance of 741 F g −1 with a high energy density of 92.4 Wh kg −1 and high power density of 6.3 kW kg −1 at the scan rate of 10 mV s −1 . Additionally, the hybrid shows good cycling stability with a retention ratio of 95% after 5000 cycles. These attractive results suggest that this 3D RGO-CNT-PANI hybrid has a great potential as an electrode material for high performance supercapacitors.