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The purpose of this study was the development and testing of a near-field communication (NFC) tag for cold chain monitoring. In this paper, we validated the use of large-surface printing technologies to make a high-frequency antenna (13.56 MHz) and carbon-based temperature sensor on an Arjowiggins' Powercoat™ paper substrate. The printed temperature sensor was connected to the output of the analog–digital converter of a commercial microprocessor. A direct temperature reading interface was developed. The main objectives were to demonstrate the potential of screen printing processes for the development of an NFC tag, and to validate the use of a printed resistive sensor for cold chain monitoring. The validation was carried out through the comparison of a reference temperature recorded by a thermocouple regarding the temperature recorded by the external printed sensor in the case of a cold chain break simulation.

Conventional bricks are the most elementary building materials for houses construction. However, the rapid growth in today's construction industry has obliged the civil engineers in searching for a new building technique that may result in even greater economy, more efficient and durable as an alternative for the conventional brick. Moreover, the high demands for having a speedy and less labour and cost building systems is one of the factor that cause the changes of the masonry conventional systems. These changes have led to improved constructability, performance, and cost as well. Several interlocking bricks has been developed and implemented in building constructions and a number of researches had studied the manufacturing of interlocking brick and its structural behaviour as load bearing and non-load bearing element. This technical paper aims to review the development of interlocking brick and its structural behaviour. In conclusion, the concept of interlocking system has been widely used as a replacement of the conventional system where it has been utilized either as load bearing or non-load bearing masonry system.

We report the realization of a resettable resistive switching device based on a nanostructured film fabricated by supersonic cluster beam deposition of gold clusters on plain paper substrates. Through the application of suitable voltage ramps, we obtain, in the same device, either a complex pattern of resistive switchings, or reproducible and stable switchings between low resistance and high resistance states, with an amplitude up to five orders of magnitude. Our device retains a state of internal resistance following the history of the applied voltage similar to that reported for memristors. The two different switching regimes in the same device are both stable, the transition between them is reversible, and it can be controlled by applying voltage ramps or by mechanical deformation of the substrate. The device behavior can be related to the formation, growth and breaking of junctions between the loosely aggregated gold clusters forming the nanostructured films. The fact that our cluster-assembled device is mechanically resettable suggests that it can be considered as the analog of the coherer: a switching device based on metallic powders used for the first radio communication system.

Drawings were made on various types of paper using lead pencils of grades from 4H through 10B. Raman spectroscopy verified both G and D peaks on all the drawings on PC print paper, PC photopaper, kent paper, and paper for silver halide print. After irradiation with a scanning femtosecond laser, silver halide paper drawn on with a 10B lead pencil maintained its surface flatness compared with the other types of paper. Raman spectroscopy on silver print paper showed a high-intensity G peak and a low-intensity D peak. After irradiating the scanning femtosecond laser on silver halide paper drawn on with a 10B lead pencil, Raman spectroscopy showed a high-intensity G peak and less intense of D peak together with a 2D peak around 2,700 cm−1 corresponding to the existence of multigraphene.

In this review we will focus on recent progress in the field of two-dimensional (2D) and three-dimensional (3D) display technologies. We present the current display materials and their applications, including organic light-emitting diodes (OLEDs), flexible OLEDs quantum dot light emitting diodes (QLEDs), active-matrix organic light emitting diodes (AMOLEDs), electronic paper (E-paper), curved displays, stereoscopic 3D displays, volumetric 3D displays, light field 3D displays, and holographic 3D displays. Conventional 2D display devices, such as liquid crystal devices (LCDs) often result in ambiguity in high-dimensional data images because of lacking true depth information. This review thus provides a detailed description of 3D display technologies.

The aim of this research is to identify the most potential vegetable raw as the material to make a bioethanol fuel as the alternative energy for gasoline. This study used experimental method. The high-level bioethanol was obtained through the process of saccharification, fermentation and stratified distillation. ASTM standards were used as the method of testing the chemical element (D 5501, D 1744, D 1688, D 512, D 2622, D 381), and physical test (D 1613, D 240, D 1298-99, D 445, and D 93). The result of the analysis showed that from the seven bioethanols being studied there is one bioethanol from Saccharum of icinarum linn that has physical and chemical properties close to the standard of bioethanol. Meanwhile, the others only meet some of the physical and chemical properties of the standard bioethanol.

By combining the appropriate Ag metallic grids with a thin functional reduced graphene oxide (MGs/F-rGO) film, a suitable photoelectric flexible electrode of the polymer solar cells (PSCs) is obtained. The conductivity and transmission of the MGs/F-rGO composited films can be improved by HNO3 modified. The optimized sheet resistance and transmission of the flexible electrode achieve to 25 Ω −1 and 83% at 550 nm wavelength. Flexible PSCs with the MGs/F-rGO electrode show 5.63% power conversion efficiency. The photoelectric properties of the MGs/F-rGO film comparable with that of ITO substrates guarantee a high short current and an enhanced PCE of the solar cells. This method provides a feasible way for fabricating low-cost and flexible PSCs.

A carbon-based inductor may serve as an important passive component in a carbon-based radio-frequency (RF) integrated circuit (IC). In this work, chemical vapor deposition (CVD) synthesized monolayer graphene and graphite inductors are fabricated and their Q-factors are investigated. We find that the large series resistance of signal path (including coil resistance and contact resistance) in monolayer graphene inductors causes negative Q-factors at the whole frequency range in measurement. Comparatively, some of the graphite inductors have all of their Q-factors above zero, due to their small signal path resistance. We also note that some other graphite inductors have negative Q-factor values at low frequency regions, but positive Q-factor values at high frequency regions. With an equivalent circuit model, we confirm that the negative Q-factors of some graphite inductors at low frequency regions are related to their relatively large contact resistances, and we are able to eliminate these negative Q-factors by improving the graphite-metal contact. Furthermore, the peak Q-factor (Qp) can be enhanced by lowering down the resistance of graphite coil. For an optimized 3/4-turn graphite inductor, the measured maximum Q-factor (Qm) can reach 2.36 and the peak Q-factor is theoretically predicted by the equivalent circuit to be as high as 6.46 at a high resonant frequency, which is beyond the testing frequency range. This research indicates that CVD synthesized graphite thin film is more suitable than graphene for fabricating inductors in carbon-based RF IC in the future.

The direct synthesis of multilayer graphene (MLG) on arbitrary substrates is essential for incorporating carbon wirings and heat spreaders into electronic devices. Here, we applied the metal-induced layer exchange (MILE) technique, developed for group-IV semiconductors, to a sputtered amorphous carbon (a-C) thin film using Co as a catalyst. MLG was formed on a SiO2 substrate at 800 °C for 10 min; however, it disappeared during wet etching for removing Co. This behavior was attributed to the small contact area between MLG and SiO2 caused by the deformation of the Co layer during annealing. By preparing the Co layer at 200 °C, its thermal stability was improved, resulting in the synthesis of MLG on the substrate through MILE. Raman measurements indicated good crystal quality of the MLG compared with that obtained by conventional metal-induced solid-phase crystallization. MILE was thus proven to be useful not only for group-IV semiconductors but also for carbon materials on insulators.

Etching with atomic hydrogen, as a preparation step before the high-temperature growth process of graphene onto a thin 3C-SiC film grown on Si(111), greatly improves the structural quality of topmost graphene layers. Pit formation and island coalescence, which are typical of graphene growth by SiC graphitization, are quenched and accompanied by widening of the graphene domain sizes to hundreds of nanometers, and by a significant reduction in surface roughness down to a single substrate bilayer. The surface reconstructions expected for graphene and the underlying layer are shown with atomic resolution by scanning tunnelling microscopy. Spectroscopic features typical of graphene are measured by core-level photoemission and Raman spectroscopy.

As an isomorph of graphene, monolayer hexagonal boron nitride (h-BN), so-called white graphene, has been in the spotlight of two-dimensional materials due to its outstanding properties. However, the growth of large and uniform white graphene monocrystalline with low density of defects is still a great challenge. Here, we present a comprehensive investigation on the growth thermokinetics of white graphene monocrystalline domains via atmospheric pressure chemical vapor deposition with the solid ammonia borane as precursors, which will be more suitable for future industrial production due to the handy process and precursor. The single domain size, coverage on substrate, and thickness of white graphene were taken as targeted parameters of products. And then, their dependences on the flow rate of carrier gas, heating temperature of ammonia borane, growth temperature and time were studied in details. Finally, after optimizing the above conditions, both white graphene monocrystalline domains as large as 80 μm2 and polycrystalline ultrathin film with coverage ratio of 95%–100% can be achieved facilely without using vacuum technique. Such white graphene products would be of great significance for the tunnel barrier for the tunneling transistor and the dielectric layers for nanocapacitor with the graphene based heterostructures.

Scanning tunneling microscopy methods are applied to investigate the potential of monolayer graphene as a sputtering shield for the underlying metal substrate. To visualize the effect, a bare and a graphene protected Ir(111) surface are irradiated with 500 eV Xe+, as well as 200 eV Xe+ and Ar+ ions, all at 1000 K. By quantitatively evaluating the sputtered material from the surface vacancy island area, we find a drastic decrease in metal sputtering for the graphene protected surface. It is demonstrated that efficient sputter protection relies on self-repair of the ion damage in graphene, which takes place efficiently in the temperature range of chemical vapor deposition growth. Based on the generality of the underlying principles of ion damage, graphene self-repair, and graphene growth, we speculate that efficient sputter protection is possible for a broad range of metals and alloys.

The thermal decomposition of silicon carbide (SiC) is a promising method for producing wafer-scale single-crystal graphene. The optimal growth condition for high-mobility epitaxial graphene fabricated by infrared rapid thermal annealing is discussed in this paper. The surface structures, such as step–terrace and graphene coverage structures, on a non-off-axis SiC(0001) substrate were well controlled by varying the annealing time in a range below 10 min. The mobility of graphene grown at 1620 °C for 5 min in 100 Torr Ar ambient had a maximum value of 2089 cm2 V−1 s−1. We found that the causes of the mobility reduction were low graphene coverage, high sheet carrier density, and nonuniformity of the step structure.

The chemical vapor deposition (CVD) of graphene on Cu has attracted much attention because of its industrial scalability. Herein, we report inductively coupled plasma-assisted CVD of epitaxially grown graphene on (111)-textured Cu film alloyed with a small amount of Ni, where large area high quality graphene film can be grown in less than 5 min at 800 °C, thus affording industrial scalability. The epitaxially grown graphene films on (111)-textured Cu contain grains which are predominantly aligned with the Cu lattice and about 10% of 30°-rotated grains (anti-grains). Such graphene films are exclusively monolayer and possess good electrical conductivity, high carrier mobility, and room temperature quantum Hall effect. Magnetoresistance measurements reveal that the reduction of the grain sizes from 150 nm to 50 nm produce increasing Anderson localization and the appearance of a transport gap. Owing to the presence of grain boundaries in these anti-grains, epitaxially grown graphene films possess n-type characteristics and exhibit ultra-high sensitivity to adsorbates.

Ultraviolet ozone (UVO) surface treatment of graphene changes its sp2-hybridized carbons to sp3-bonded carbons, and introduces oxygen-containing components. Oxidized graphene has a finite energy band gap, so UVO modification of the surface of a four-layered graphene anode increases its surface ionization potential up to ~5.2 eV and improves the hole injection efficiency (η) in organic electronic devices by reducing the energy barrier between the graphene anode and overlying organic layers. By controlling the conditions of the UVO treatment, the electrical properties of the graphene can be tuned to improve η. This controlled surface modification of the graphene will provide a way to achieve efficient and stable flexible displays and solid-state lighting.

Graphene, a monoatomic layer of graphite, hosts a two-dimensional electron gas system with large electron mobilities which makes it a prospective candidate for future carbon nanodevices. Grown epitaxially on silicon carbide (SiC) wafers, large area graphene samples appear feasible and integration in existing device technology can be envisioned. This paper reviews the controlled growth of epitaxial graphene layers on SiC(0 0 0 1) and the manipulation of their electronic structure. We show that epitaxial graphene on SiC grows on top of a carbon interface layer that—although it has a graphite-like atomic structure—does not display the linear π-bands typical for graphene due to a strong covalent bonding to the substrate. Only the second carbon layer on top of this interface acts like monolayer graphene. With a further carbon layer, a graphene bilayer system develops. During the growth of epitaxial graphene on SiC(0 0 0 1) the number of graphene layers can be precisely controlled by monitoring the π-band structure. Experimental fingerprints for in situ growth control could be established. However, due to the influence of the interface layer, epitaxial graphene on SiC(0 0 0 1) is intrinsically n-doped and the layers have a long-range corrugation in their density of states. As a result, the Dirac point energy where the π-bands cross is shifted away from the Fermi energy, so that the ambipolar properties of graphene cannot be exploited. We demonstrate methods to compensate and eliminate this structural and electronic influence of the interface. We show that the band structure of epitaxial graphene on SiC(0 0 0 1) can be precisely tailored by functionalizing the graphene surface with tetrafluoro-tetracyanoquinodimethane (F4-TCNQ) molecules. Charge neutrality can be achieved for mono- and bilayer graphene. On epitaxial bilayer graphene, where a band gap opens due to the asymmetric electric field across the layers imposed by the interface, the magnitude of this band gap can be increased up to more than double its initial value. The hole doping allows the Fermi level to shift into the energy band gap. The impact of the interface layer can be completely eliminated by decoupling the graphene from the SiC substrate by a hydrogen intercalation technique. We demonstrate that hydrogen can migrate under the interface layer and passivate the underlying SiC substrate. The interface layer alone transforms into a quasi-free standing monolayer. Epitaxial monolayer graphene turns into a decoupled bilayer. In combination with atmospheric pressure graphitization, the intercalation process allows the production of quasi-free standing epitaxial graphene on large SiC wafers and represents a highly promising route towards epitaxial graphene based nanoelectronics.

Almost 15 years have gone ever since the discovery of graphene as a single atom layer. Numerous papers have been published to demonstrate its high electron mobility, excellent thermal and mechanical as well as optical properties. We have recently seen more and more applications towards using graphene in commercial products. This paper is an attempt to review and summarize the current status of the research of the thermal properties of graphene and other 2D based materials including the manufacturing and characterization techniques and their applications, especially in electronics and power modules. It is obvious from the review that graphene has penetrated the market and gets more and more applications in commercial electronics thermal management context. In the paper, we also made a critical analysis of how mature the manufacturing processes are; what are the accuracies and challenges with the various characterization techniques and what are the remaining questions and issues left before we see further more applications in this exciting and fascinating field., YF, JH, YL, AZ, MK and JL acknowledge the financial support from The Swedish National Science Foundation (VR under the contract No 621-2007-4660), The Swedish Foundation for Strategic Research (SSF) under contract (No SE13-0061), the Swedish Board for innovation under the Siografen program and from the Production Area of Advance at Chalmers University of Technology, Sweden. SC, YZ and JL acknowledge the financial support by the Key R&D Development Program from the Ministry of Science and Technology of China with the contract No: 2017YFB040600 and the National Natural Science Foundation of China (No. 51872182). XX is supported the National Natural Science Foundation of China (No. 11674245 & No. 11890703). MS and CMST acknowledge financial support from the CERCA programme/Generalitat de Catalunya, the Severo Ochoa Centres of Excellence programme, funded by the Spanish Research Agency (AEI, Grant No. SEV-2017-0706).

The aim of this paper is to identify, analyze and compare the defects present in III-As, as a function of dislocation density, and as a function of the presence/absence of quantum dots (QDs). Such materials are of fundamental importance for the development of lasers and photodiodes for silicon photonics. The study is based on an extensive deep-level transient spectroscopy investigation, carried out on GaAs pin diodes grown on Si and on GaAs (that differ in the dislocation density), with and without embedded QDs. The original results described in this paper demonstrate that: (a) we were able to identify four different defects within the device grown on Si (three electron and one hole traps) and one defect (hole trap) in the device on GaAs, common to both samples; (b) all the majority carrier traps identified are located near midgap, i.e. are efficient non-radiative recombination centers; (c) such defects are absent (or non-detectable) in the sample grown on GaAs substrate, having a very low dislocation density; (d) the presence of QDs does not result in additional defects within the semiconductor material; (e) the analysis of the capture kinetics revealed that two of the identified traps are related to point defects, whereas the other two traps can be associated with point defects located near a dislocation; (f) a comparison with previous reports indicate that the detected traps are related to native III-As defects, or to oxygen-related complexes.

This paper presents the second version of the efficiency tables of materials considered as emerging inorganic absorbers for photovoltaic solar cell technologies. The materials collected in these tables are selected based on their progress in recent years, and their demonstrated potential as future photovoltaic absorbers. The first part of the paper consists of the guidelines for the inclusion of the different technologies in this paper, the verification means used by the authors, and recommendation for measurement best practices. The second part details the highest world-class certified solar cell efficiencies, and the highest non-certified cases (some independently confirmed). The third part highlights the new entries including the record efficiencies, as well as new materials included in this version of the tables. The final part is dedicated to review a specific aspect of materials research that the authors consider of high relevance for the scientific community. In this version of the efficiency tables, we are including an overview of the latest progress in quasi one-dimensional absorbers, such as antimony chalcogenides, for photovoltaic applications.

We present in this paper the vertical integration of an electro-absorption modulator (EAM) onto a vertical-cavity surface-emitting laser (VCSEL). We discuss the design, fabrication, and measured characteristics of the combined VCSEL and EAM. We previously demonstrated a standalone EAM with an optical bandwidth around 30 GHz. In this paper we present for the first time an optical bandwidth of 30 GHz for an EAM integrated onto a VCSEL. This device exhibits single-mode operation and a very low chirp, below 0.1 nm, even with a modulation depth of 70% which makes this device very competitive for high-speed communications in data centers.

This paper presents, for the first time, a multimodal sensor for characterizing relative permittivity of plastic polymers by integrating in a single sensor (1) frequency-reconfigurable resonance technique at 98 and 100 GHz, and (2) 80–100 GHz broadband modified transmission-line technique. The sensor is designed based on a custom-made WR-10 waveguide featuring dual rectangular complementary split-ring resonators (CSRRs). By loading the CSRRs with a material-under-test (MUT), the reflected and transmitted electromagnetic waves propagating inside the waveguide are changed depending on the dielectric properties of the material. Various plastic polymer materials, e.g. polytetrafluoroethylene (PTFE), polymethylmethacrylate (PMMA) and high-density polyethylene (HDPE), are characterized. The sensor in this paper offers various key advantages over any state-of-the-art material characterization techniques at millimeter-wave frequencies, e.g. multiple characterization techniques integrated in a single device, miniaturization, much higher tolerance to changes in the measurement environment, ease of design and fabrication, and better cost effectiveness.

Realizing the layouts of analog/mixed-signal (AMS) integrated circuits (ICs) is a complicated task due to the high design flexibility and sensitive circuit performance. Compared with the advancements of digital IC layout automation, analog IC layout design is still heavily manual, which leads to a more time-consuming and error-prone process. In recent years, significant progress has been made in automated analog layout design with emerging of several open-source frameworks. This paper firstly reviews the existing state-of-the art AMS layout synthesis frameworks with focus on the different approaches and their individual challenges. We then present recent research trends and opportunities in the field. Finally, we summaries the paper with open questions and future directions for fully-automating the analog IC layout.

The memristor is a kind of non-linear element with memory function, which can be applied to chaotic systems to increase signal randomness and complexity. In this paper, a new four-dimensional hyper-chaotic system is designed based on a flux controlled memristor model, which can generate complex chaotic attractors. The basic dynamic theory analysis and numerical simulations of the system, such as the stability of equilibrium points, the Lyapunov exponents and dimension, Poincare maps, the power spectrum, and the waveform graph prove that it has rich dynamic behaviors. Then, the circuit implementation of this system is established. The consistency of simulation program with integrated circuit emphasis (SPICE) simulation and numerical analysis proves the ability to generate chaos. Finally, a new image encryption scheme is designed by using the memristor-based hyper-chaotic system proposed in this paper. The scheme involves a total of two encryptions. By using different security analysis factors, the proposed algorithm is compared with other image encryption schemes, including correlation analysis, information entropy, etc. The results show that the proposed image encryption scheme has a large key space and presents a better encryption effect.

Objective: This paper describes the design, testing and use of a novel multichannel block-capable stimulator for acute neurophysiology experiments to study highly selective neural interfacing techniques. This paper demonstrates the stimulator's ability to excite and inhibit nerve activity in the rat sciatic nerve model concurrently using monophasic and biphasic nerve stimulation as well as high-frequency alternating current (HFAC). Approach: The proposed stimulator uses a Howland Current Pump circuit as the main analogue stimulator element. 4 current output channels with a common return path were implemented on printed circuit board using Commercial Off-The-Shelf components. Programmable operation is carried out by an ARM Cortex-M4 Microcontroller on the Freescale freedom development platform (K64F). Main Results: This stimulator design achieves +-10 mA of output current with +-15 V of compliance and less than 6 uA of resolution using a quad-channel 12-bit external DAC, for four independently driven channels. This allows the stimulator to carry out both excitatory and inhibitory (HFAC block) stimulation. DC Output impedance is above 1 Mohm. Overall cost for materials i.e. PCB boards and electronic components is less than USD 450 or GBP 350 and device size is approximately 9 cm x 6 cm x 5 cm. Significance: Experimental neurophysiology often requires significant investment in bulky equipment for specific stimulation requirements, especially when using HFAC block. Different stimulators have limited means of communicating with each other, making protocols more complicated. This device provides an effective solution for multi-channel stimulation and block of nerves, enabling studies on selective neural interfacing in acute scenarios with an affordable, portable and space-saving design for the laboratory. The stimulator can be further upgraded with additional modules to extend functionality while maintaining straightforward programming and integration of functions with one controller. Additionally, all source files including all code and PCB design files are freely available to the community to use and further develop.

CMOS technology is one of the most frequently used technologies in the semiconductor industry as it can be successfully integrated with ICs. Every two years the number of MOS transistors doubles because the size of the MOSFET is reduced. Reducing the size of the MOSFET reduces the size of the channel length which causes short channel effects and it increases the leakage current. To reduce the short channel effects new designs and technologies are implemented. Double gate MOSFET design has shown improvement in performance as amplifiers over a single MOSFET. Silicon-based MOSFET design can be used in a harsh environment. It has been used in various applications such as in detecting biomolecules. The increase in number of gates increases the current drive capability of transistors. GAA MOSFET is an example of a quadruple gate around the four sides of channel that increases gate control over the channel region. It also increases effective channel width that improves drain current and reduces leakage current keeping short channel effects under limit. Junctionless MOSFET operates faster and uses less power with increase in ON-state current leading to a good value of I ON/I OFF ratio. In this paper, several gate and channel engineered MOSFET structures are analyzed and compared for sub 45 nm technology node. A comparison among different MOSFET structures has been made for subthreshold performance parameters in terms of I OFF, subthreshold slope and DIBL values. The analog/RF performance is analyzed for transconductance, effective transistor capacitances, stability factor and critical frequency. The paper also covers different applications of advance MOSFET structures in analog/digital or IoT/ biomedical applications.

The lossy mode resonance (LMR)-based optical fiber waveguide based on titanium dioxide nanoarrays was discovered and researched for the first time in this paper. Two kinds of waveguide coating structures, titanium dioxide nanoarrays and nanofilms-nanoarrays systems, were researched using finite element method, where the localized field distribution, the mode transmission characteristics and measurement sensitivities of surrounding refractive index were researched in detail. In the former structure, there exists a localized electromagnetic field that can be generated by both TE and TM polarization modes around nanoarrays. By increasing the diameters of nanoparticles and decreasing the intervals of nanoarrays, the resonance wavelength will redshift and the measurement sensitivity will be enhanced. In the latter structure, the localized electromagnetic field can be obviously enhanced due to the mode coupling between nanofilms and nanoarrays. In addition, the measurement sensitivity of refractive index was 5179 nm/RIU in the range of 1.333–1.343, which is two times higher than that of the structure without TiO2 nanoarrays. This paper opened up a door to study the LMR generated by semiconductor nanoparticles, which is useful in the research of electromagnetic resonance-based sensors in nanoscales.

Germanium on silicon P-i-N photodetectors fabricated using standard CMOS tools are now successfully used as uncooled detectors in the near-infrared (NIR), which extends from 0.75 to 1.4 μm and in the short-wave infrared (SWIR), which extends from 1.4 to 3 μm. They feature a remarkably high responsivity up to 1550 nm and a low dark current when they are operated at reverse biases. The aim is to achieve a very low dark current density and a high responsivity with a small Germanium photodiode pitch. In this paper we discuss the fabrication and the characterization of vertical P-i-N photodiodes with the epitaxy of Germanium on Silicon. The Germanium epilayer is a 1.3 μm thick Ge film with a bottom Ge layer P-type doped with boron at 1019 cm−3 and a top Ge layer N-type doped with phosphorus at 1020 cm−3. Secondary ion mass spectroscopy was used to assess the doping level of the Phosphorus doped N + region. The strain in the Germanium epilayer on Silicon substrate was investigated. It was tensile, with a value around +0.15% from x-ray diffraction (XRD), in good agreement with a +0.12% value from Raman spectroscopy. In this paper, we focus on P-i-N photodiodes with a circular shape and a diameter of 10 μm. Electrical characterizations were performed in dark and under NIR-SWIR radiation (1310 nm, 1550 nm), with very low dark current of 0.45 nA and enhanced photocurrent at −1 V. The external responsivities were measured at 0.275 and 0.133 A W−1 for 1310 nm and 1550 nm, respectively. Finally, internal quantum efficiencies of the fabricated vertical P-i-N photodiodes were extracted at 66% and 52% at 1310 nm and 1550 nm, respectively, in good agreement with TCAD simulations. Finally, a measurement of the noise in dark conditions is presented.

Biodiesel is an important renewable energy candidate for the future energy. To improve the fuel properties, many experimental works and trial for the fuel blend. The fuel enrichment method by addition of nano-additives is widely accepted by numerous researchers. The nano-additives are used to achieve specific fuel properties and to improve the performance characteristics and to attain a good emission control of the Compression Ignition (CI) engine without any modification. It is important to blend in right concentration in order to avoid the effect on fuel properties. This paper reports the calculation on how to measure concentration of blending biodiesel fuel with nanoparticles with the appropriate method which is mass concentration method. This paper investigates the details of concentration measurements of blending biodiesel (B7) with SiO2 nanoparticle by using the mass fraction method for only 0.5 liter of fuel. This method also can use for other types of fuel and nanoparticles. Thus, by using the correct method of mass concentration would not be affect to its fuel properties, engine performance and also exhaust emissions.

Almost all the solar cells created so far have been based on electronic charge. This paper reports a photovoltaic effect based on the spin property of electrons. This spin-based photovoltaic effect was observed on magnetic tunnel junction based molecular spintronics devices (MTJMSD). MTJMSDs were produced by covalently bonding organometallic molecular clusters (OMCs) between the top and bottom ferromagnetic electrodes of Co/NiFe/AlOx/NiFe magnetic tunnel junctions along the exposed side edges. The MTJMSD configuration, which showed the photovoltaic effect, also exhibited OMC induced strong antiferromagnetic coupling (Tyagi et al 2015 Nanotechnology 26 305602) and room temperature current suppression (Tyagi et al 2019 Org. Electron. 64 188-194). Our MTJMSD were fabricated below 100 °C temperature and employed earth-abundant transition metals like nickel and iron. This paper shows that the MTJMSD's photovoltaic effect was susceptible to the magnetic field, temperature, and light intensity. The solar cell efficiency was estimated to be ∼3%. Our MTJMSD approach provides a mass-producible platform for harvesting solar energy and opens a myriad of opportunities to incorporate photogenerated charges for the logic and memory operation in the molecular spintronics devices.

Conventional nuclear power reactors convert between 30 – 35 % only of the total energy input into electricity while the remaining was wasted. The waste heat is sometimes used for desalination processes while the remaining heat is transferred to a cooling media or lost to the surrounding. Therefore, heat from nuclear reactor can be used to produce heat and power, as well as for cooling in a trigeneration system. This paper presents the Trigeneration System Cascade Analysis (TriGenSCA) for an optimal Pressurised Water Reactor (PWR) design. The TriGenSCA framework allows engineers to determine an optimum utility generation system size and estimate the required amount of external utilities. The analysis includes data extraction, cascade analysis for size estimation and calculation of the new trigeneration system size. The technique also enables users to determine accurate results for energy minimisation based on demand fluctuations. Application of the framework on a case study presented on this paper demonstrates the trigeneration PWR system successfully saved energy of 328GWh/y (97 %).

Optofluidic lasers have been widely investigated over the last few years mainly because they can be easily integrated in sensor devices. However, high power pulse lasers are required as excitation sources, which, in practice, limit the portability of the system. Trying to overcome some of these limitations, in this paper we propose the combined use of a small CW laser with a Fabry-Perot optofluidic planar microcavity showing high sensitivity and versatility for detection of liquid properties and label-free sensing. Firstly, a fluorescein solution in ethanol is used to demonstrate the high performances of the FP microcavity as a temperature sensor both in the laser (high pump power above laser threshold) and in the fluorescence (low pump power) regimes. A shift in the wavelength of the resonan cavity modes is used to detect changes in the temperature and our results show that high sensitivities could be already obtained using cheap and portable CW diode lasers. In the second part of the paper, the demonstration of this portable device for label-free sensing is illustrated under low CW pumping. The wavelength positions of the optofluidic resonant modes are used to detect glucose concentrations in water solutions using a protein labelled with a fluorescent dye as the active medium., This research was supported by European Regional Development Funds program (EU-FEDER), Agencia Estatal de Investigación (AEI) and MINECO (SAF2014-61644-EXP), (MAT2013-40852-R), (MAT2013-46649-C4-4-P), (MAT2015-71070-REDC), (MAT2016-79866-R), (MAT2016-75586-C4-4-P), FUNCOAT (CSD2008-00023), and by the Junta de Andalucía (projects P12-FQM-2265 and P10-FQM-6900).

Near-interfacial oxide traps and chemical impurities on the graphene surface or at the graphene-dielectric interface can be a source of intentional or unintentional doping of graphene sheet. The efficiency of such chemical doping can vary in a wide range depending on parameters of graphene field effect devices. Mechanisms of such sensitivity of doping efficiency to the device characteristics need to be understood. The objective of this paper is to theoretically derive the analytical relations, adapted to the explicit calculation of graphene chemical doping., 5 pages, 2 figures, Mokerov Conference (2016) open access paper

This paper presents the first phase of design, analysis, and simulation for the klystron coaxial radio frequency (RF) output window. This study is motivated by 800 kW continuous wave (CW), 650 MHz klystrons for the future plan of circular electron-positron collider (CEPC) project. The RF window which is used in the klystron output section has a function to separate the klystron from the inner vacuum side to the outside, and high RF power propagates through the window with small power dissipation. Therefore, the window is a key component for the high power klystron. However, it is vulnerable to the high thermal stress and multipacting, so this paper presents the window design and analysis for these problems. The microwave design has been performed by using the computer simulation technology (CST) microwave studio and the return loss of the window has been established to be less than -90 dB. The multipacting simulation of the window has been carried out using MultiPac and CST particles studio. Through the multipacting analysis, it is shown that with thin coating of TiN, the multipacting effect has been suppressed effectively on the ceramic surface. The thermal analysis is carried out using ANSYS code and the temperature of alumina ceramic is lower than 310 K with water cooling. The design result successfully meets the requirement of the CEPC 650 MHz klystron. The manufacturing and high power test plan are also described in this paper.

This paper reports on the developments of a study done to establish the feasibility of implementing Linear Friction Welding (LFW) as a joining technique for small axis-symmetrical Ti6Al4V samples. This work will attempt to facilitate the manufacturing of high-integrity small near-net-shape components for aerospace, automotive and medical applications. LFW is a solid-state welding technique that utilises frictional heat generated by the rubbing of surfaces under an axially applied load, thereby forming a weld at temperatures below the beta transus point. The technique is advantageous as it has the potential to reduce defects normally associated with conventional welding of this material. This paper will describe the development of an experimental platform, which will facilitate the evaluation of the influence of selected process parameters and their influence on joint integrity. Process parameters that will form the basis of this study include axial load (weld interface force), consumed length (axial shortening), oscillating amplitude and frequency. Welds made on this platform will allow for the characterisation of the microstructural change across the weld zone or regions exhibiting grain refinement, linking this to the mechanical properties of the joint region. The study will create an understanding of how process parameters can be manipulated to achieve optimum joint properties or assist in eliminating weld defects. Knowledge generated will form the basis for developing a bench-top LFW research platform, with a reliable closed-loop response system that will aid in studying the effects of welding parameters on joint integrity of small titanium components.

At present, many automakers are paying attention to develop vehicles with IoT enabled including healthcare, accident prevention, vehicle safety, driver safety, driver and passenger comfort, vehicle monitoring, etc. This paper focused on reviewing the recent developments in driver's health and comfort monitoring through IoT. The literature review was performed with popular search engines/databases like PubMed, ScienceDirect, Elsevier Science, Scopus, and Google Scholar. The search was based on keywords like "Healthcare Monitoring", "Seating Comfort", "IoT developments", "Smart Sensing", "Embedded Sensors", "Wearable Sensors", "in-vehicle smart assistance", "Autonomous Vehicle/Car". Later, the articles were sorted out according to the relevance of this paper's focus (i.e., driver's health and comfort monitoring through IoT) by reading title, abstract, and full article. The results show that there have been many IoT based health and comfort monitoring developments concerning the vehicle. We have classified and summarised the developments as health monitoring through seat pan, seat back, seat belt, steering wheel, eye tracking and face tracking, and comfort monitoring/enhancement through smart seating, smart seat cushion, smart door module, smart air-bag, smart seat belt buckles. This survey would be giving in-depth knowledge on recent developments in the field of automotive and IoT.

Due to the output voltage characteristics of the photovoltaic cell and other renewable energy generation systems, DC/DC converter with high step-up ratio is commonly needed to raise the voltage. The high gain Boost converter based on coupled inductor with switch capacitor network is presented in this paper. The proposed converter avoid the ultimate duty cycle by designing the ratio of the coupling inductor. As the energy of leakage inductor in the input side can be transferred to the output side, the loss of leakage inductor is reduced. The voltage peak of the switch is inhibited by the switching capacitor, which greatly reduces the voltage stress of the switch, thus the converter improves the transfer efficiency. The working state of the converter is analyzed in detail, the theoretical formula is derived, and the stress of the converter is analyzed in the paper. A simulation circuit is built to verify the theoretical analysis.

In this paper, a three-layer chiral structure is proposed to achieve the conversion of its performance between broadband circular polarization asymmetric transmission and broadband circular dichroism by rotating the upper layer of the structure. For circular polarization asymmetric transmission, its asymmetric transmission parameters can reach a maximum of 0.89 and over 0.5 from 134 to 225 THz. For circular dichroism, the co-polarized transmission coefficient of right-handed circularly polarized wave is above 0.8 and the co-polarized transmission coefficient of left-handed circularly polarized wave is lower than 0.25 from 137 to 214 THz. The above results have not been reported in previous papers. This structure provides potential applications for circular polarization converters and circular polarizers.

This paper researches the rotor position detection, presents a control system based on DSP TMS320F2812 for position sensor-less BLDC motor. Besides, the paper analyzes the control system and describes the composed hardware, software design and control strategy. This system can greatly simplify the hardware construction, and control the motor efficiently and stably.

In the laser - solid target experiments at ELI-NP, maximizing the availability of the laser system and hence the number of shots during a campaign is envisaged. One of the factors that affects this is the time for preparing the experiment and the time for changing the targets between shots. In this paper we present a method for automatic rough alignment of various experimental setup instruments like the target frames, microscopes and diagnostics. Giving the impossibility to define a global reference system that captures precisely enough the relative position of all equipment in a continuously changing experimental setup, the method developed is using relative optical measurements using fiducial markers. The method is conceived to be used along with other micron-level alignment methods as a pre-alignment phase. Along this work, a setup and the algorithms were developed in order to test the accuracy of the method. First tests revealed a rough alignment accuracy between 100-200μm which was achieved using only a low resolution imaging camera. The accuracy can be further improved using higher resolution imaging systems or by developing new key points in the algorithm that are discussed at the end of the paper.

Lighting system is an important sub-system in office buildings. A good design can contribute energy saving and visual comfort to occupants. This paper presents a comparison of lighting system design according to different standards: European Standard EN12464-1 and Malaysian Standard MS1525 in terms of average illuminance level and illuminance uniformity. In the design, the illuminance measurement is according to the Illuminating Engineering Society of North America (IESNA) and the European Standard EN12464-1. Three types of luminaires are considered which are: T8, T5 and light emitting diode (LED) lamps. The technical and economic evaluations are taken into account in this paper. The technical evaluations are considered the number of luminaires, average illuminance level and illuminance uniformity. The energy consumption (EC) and lighting energy numeric indicator (LENI) are considered according to the European Standard EN15193. Meanwhile, the economic evaluation involves billings and luminaires costs and billing savings. The case study is an office room and it is modelled and simulated using DIALux software. The results show that the design according to the European Standard EN12464-1 with uniformity based method that used T5 lamps had contributed to the highest number of luminaires and costs. Whereas, the design according to the Malaysian Standard MS1525 with illuminance level based method that used LED lamps had contributed to the lowest number of luminaires and costs. Thus it can provide the higher billing savings. It can be concluded the LED has great potential to replace T8 and T5 lamps.

We propose a slim optical fingerprint sensor for fake fingerprint detection on mobile environment. The sensor proposed in this paper is compact size and slim thickness. Also, it can be used by only the power of smart phone without battery or external power. This sensor has a new lens design and optical path to minimize distortion. This sensor shows detailed images of ridges and valleys characteristic of fingerprints and has a characteristic of being resistant to moisture. The proposed sensor can detect various kinds of fake fingerprint (Paper, rubber, silicone, etc.). Simulations show that the slim optical fingerprint sensor has an effective performance on the results of the fake fingerprint detection rate.

MANET (Mobile Ad Hoc Network) researchers have shown increased interest in using mobile robot technology for their testbed platforms. Thus, the main motivation of this paper is to review various robot-based MANET testbeds that have been developed in previously reported research. Additionally, suggestions to heighten mobility mechanisms by using mobile robots to be more practical, easy and inexpensive are also included in this paper, as we unveils ToMRobot, a low-cost MANET robot created from an ordinary remote control car that is capable of performing a real system MANET testbed with the addition of only a few low-cost electronic components. Despite greatly reduced costs, the ToMRobot does not sacrifice any of the necessary MANET basic structures and will still be easily customisable and upgradeable through the use of open hardware technology like Cubieboard2 and Arduino, as its robot controller. This paper will also include guidelines to enable technically limited MANET researchers to design and develop the ToMRobot. It is hoped that this paper achieves its two pronged objectives namely (i) to facilitate other MANET researchers by providing them with a source of reference that eases their decision making for selecting the best and most suitable MANET mobile robots for real mobility in their MANET testbeds (ii) to provide MANET researchers with a prospect of building their own MANET robots that can be applied in their own MANET testbed in the future.

Deployment of large scale wind turbine parks, in particular offshore, requires well organized operation and maintenance strategies to make it as competitive as the classical electric power stations. It is important to ensure systems are safe, profitable, and cost-effective. In this regards, the ability to detect, isolate, estimate, and prognose faults plays an important role. One of the critical wind turbine components is the gearbox. Failures in the gearbox are costly both due to the cost of the gearbox itself and also due to high repair downtime. In order to detect faults as fast as possible to prevent them to develop into failure, statistical change detection is used in this paper. The Cumulative Sum Method (CUSUM) is employed to detect possible defects in the downwind main bearing. A high fidelity gearbox model on a 5-MW spar-type wind turbine is used to generate data for fault-free and faulty conditions of the bearing at the rated wind speed and the associated wave condition. Acceleration measurements are utilized to find residuals used to indirectly detect damages in the bearing. Residuals are found to be nonGaussian, following a t-distribution with multivariable characteristic parameters. The results in this paper show how the diagnostic scheme can detect change with desired false alarm and detection probabilities.

This paper reports on the development of a technology for the wafer-level fabrication of an optical Michelson interferometer, which is an essential component in a micro optoelectromechanical system (MOEMS) for a miniaturized optical coherence tomography (OCT) system. The MOEMS consists on a titanium dioxide/silicon dioxide dielectric beam splitter and chromium/gold micro-mirrors. These optical components are deposited on 45° tilted surfaces to allow the horizontal/vertical separation of the incident beam in the final microintegrated system. The fabrication process consists of 45° saw dicing of a glass substrate and the subsequent deposition of dielectric multilayers and metal layers. The 45° saw dicing is fully characterized in this paper, which also includes an analysis of the roughness. The optimum process results in surfaces with a roughness of 19.76 nm (rms). The actual saw dicing process for a high-quality final surface results as a compromise between the dicing blade’s grit size (#1200) and the cutting speed (0.3mm s−1). The proposed wafer-level fabrication allows rapid and low-cost processing, high compactness and the possibility of wafer-level alignment/ assembly with other optical micro components for OCT integrated imaging, This work is supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 - Programa Operacional Competitividade e Internacionalizacao (POCI) with the reference project POCI-01-0145-FEDER-006941., info:eu-repo/semantics/publishedVersion

The application and characterization of thermal interface material (TIM) for vibrational structures is investigated in this paper. The vibrating feature during the operation requires unique solution for its thermal management, since the connection between the device and heat dissipater should be able to conduct heat efficiently and impose minimum constraint onto the vibration simultaneously. As a typical vibrational device, piezoelectric transformers (PTs) are discussed in this paper. The PTs have urgent demands for thermal dissipation since their power conversion efficiency decrease rapidly with the rising temperature. A novel method by applying vertically aligned carbon nanotube (VACNT) arrays to the interface between PT and heat dissipater is presented to enhance the performance of piezoelectric transformers. VACNT arrays are one of the excellent TIMs. It can directly establish thermal contact between two surfaces by van der Waals' forces. In addition, the unique anisotropic character of CNT arrays provides enough flexibility to accommodate the vibration during the operation. Different configurations of TIMs are compared with each other in this work, including CNT arrays, tape of polypropylene (PP) membrane and without heat transfer structure (HTS). The results indicate that the temperature rise is lowest and the efficiency is highest at the same power density while CNT arrays served as the TIM. Almost no significant fretting and wearing damage occurred on PT electrode surface with CNT arrays TIM even after working continuously for 120 days. Meanwhile, the thermo-physical properties of CNT arrays at contact interface are measured by optical transient thermo-reflectance technique.

This work explores the practical functionality of ultra-high frequency (UHF) radio frequency identification (RFID) tags screen printed onto various low-cost, flexible substrates. The need for integrated and automated low-cost point-of-care diagnostic solutions has driven the development of automated sensing and connectivity for implementation with these devices. This work explores wireless communication for paper-based point-of-care diagnostic solutions through screen printing of UHF RFID tags onto various low-cost and flexible substrates. Manual screen printing and assembly of RFID sensor integrated circuit packages and UHF RFID dipole antennas onto various substrates was performed and the practical functionality of these tags was assessed. Print quality including parameters such as resistance, roughness and print thickness are reported to illustrate the effect of the substrate on the printed result. Practical read range measurements are presented for the various tags in passive and active modes, as well as with a load connected, for different tag orientations. Results showed that the tags are adequate for clinical requirements with read ranges of at least 75 mm achieved in passive mode across the different substrates. Our results indicate that a variety of low-cost substrates can be utilized as different packaging and label options for paper-based diagnostic tests. This work presents the feasibility of implementing such devices towards low-cost, integrated point-of-care diagnostics, using straightforward fabrication techniques and realistic testing environments to illustrate the possibilities.

As dynamic loading experiments such as a shock compression test are usually characterized by short duration, unrepeatability and high costs, high temporal resolution and precise accuracy of the measurements is required. Due to high temporal resolution up to a ten-nanosecond-scale, a Stokes polarimeter with six parallel channels has been developed to capture such instantaneous changes in optical properties in this paper. Since the measurement accuracy heavily depends on the configuration of the probing beam incident angle and the polarizer azimuth angle, it is important to select an optimal combination from the numerous options. In this paper, a systematic error propagation-based measurement configuration optimization method corresponding to the Stokes polarimeter was proposed. The maximal Frobenius norm of the combinatorial matrix of the configuration error propagating matrix and the intrinsic error propagating matrix is introduced to assess the measurement accuracy. The optimal configuration for thickness measurement of a SiO2 thin film deposited on a Si substrate has been achieved by minimizing the merit function. Simulation and experimental results show a good agreement between the optimal measurement configuration achieved experimentally using the polarimeter and the theoretical prediction. In particular, the experimental result shows that the relative error in the thickness measurement can be reduced from 6% to 1% by using the optimal polarizer azimuth angle when the incident angle is 45°. Furthermore, the optimal configuration for the dynamic metrology of a nickel foil under quasi-dynamic loading is investigated using the proposed optimization method.