mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
Radiation effect on the optical and electrical properties of CdSe(In)/p-Siheterojunction photovoltaic solar cells

The efficiency and radiation resistance of solar cells are graded. They are then fabricated in the formof n-CdeSe(In)/p-Si heterojunction cells by electron beam evaporation of a stoichiomteric mixture of CdSe andIn to make a thin film on a p-Si single crystal wafer with a thickness of 100 μm and a resistivity of?1.5 ?.cmat a temperature of 473 K. The short-circuit current density (j~(sc)), open-circuit voltage (V~(oc)), fill factor (ff) andconversion efficiency (η) under 100 mW/cm~2 (AM1) intensity, are 20 mA/cm~2, 0.49 V, 0.71 and 6% respectively.The cells were exposed to different electron doses (electron beam accelerator of energy 1.5 MeV, and beam intensity25 mA). The cell performance parameters are measured and discussed before and after gamma and electron beamirradiation.
A low power 14 bit 51.2 kS/s double-sampling extended counting ADC with a class-AB OTA

A 14 bit 51.2 kS/s extended counting analog to digital converter (EC-ADC) is presented. Two techniques are utilized to reduce its power consumption. First, a double-sampling configuration based on a fully-floating bilinear integrator is proposed to reduce the clock frequency. Second, a class-AB operational transconductance amplifier (OTA) is designed to improve the power efficiency. In addition, the chopping technique is used to eliminate the OTA flicker noise effect. The proposed ADC is fabricated in 0.18 μm CMOS technology with a core area of 0.04 mm~2. At a 51.2 kS/s conversion rate, it achieves a 94 dB SFDR and an 11.6 bit ENOB, while consuming only 77μW from a 1.8 V power supply. The figure of merit is only 0.48 pJ/step.
Ways to suppress click and pop for class D amplifiers

Undesirable audio click and pop may be generated in a speaker or headphone. Compared to linear (class A/B/AB) amplifiers, class D amplifiers that comprise of an input stage and a modulation stage are more prone to producing click and pop. This article analyzes sources that generate click and pop in class D amplifiers, and corresponding ways to suppress them. For a class D amplifier with a single-ended input, click and pop is likely to be due to two factors. One is from a voltage difference (VDIF) between the voltage of an input capacitance (VCIN) and a reference voltage (VREF) of the input stage, and the other one is from the non-linear switching during the setting up of the bias and feedback voltages/currents (BFVC) of the modulation stage. In this article, a fast charging loop is introduced into the input stage to charge VCIN to roughly near VREF-Then a correction loop further charges or discharges VCIN substantially equalizing it with VREF. Dummy switches are introduced into the modulation stage to provide switching signals for setting up BFVC, and the power switches are disabled until the BFVC are set up successfully. A two channel single-ended class D amplifier with the above features is fabricated with 0.5 μm Bi-CMOS process. Road test and fast Fourier transform analysis indicate that there is no noticeable click and pop.
Effect of ZnO films on CdTe solar cells

The ZnO high resistivity transparent (HRT) layers were prepared by DC magnetron sputtering on the 1 mm borosilicate glass with 150 nm ITO coating. The structural, optical and electrical properties of the as-deposited films were investigated by XRD, UV/Vis spectroscopy and four-probe technology. The interface characters of the ITO/ZnO and ZnO/CdS systems were studied by ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) depth profiling tests. The results show that ZnO has good optical and electrical properties. The insertion of the ZnO films decreases the energy barrier between ITO and CdS films. The energy conversion efficiency and quantum efficiency were found to be 12.77% (8.9%) and > 90% (79%) with or (without) ZnO films of CdTe solar cells. Furthermore, the effect of thickness, mobility and carrier density of ZnO films on CdTe solar cells was analyzed by AMPD-1D.
Double-π fully scalable model for on-chip spiral inductors

A novel double-π equivalent circuit model for on-chip spiral inductors is presented. A hierarchical structure, similar to that of MOS models is introduced. This enables a strict partition of the geometry scaling in the global model and the model equations in the local model. The major parasitic effects, including the skin effect, the proximity effect, the inductive and capacitive loss in the substrate, and the distributed effect, are analytically calculated with geometric and process parameters in the local-level. As accurate values of the layout and process parameters are difficult to obtain, a set of model parameters is introduced to correct the errors caused by using these given inaccurate layout and process parameters at the local level. Scaling rules are defined to enable the formation of models that describe the behavior of the inductors of a variety of geometric dimensions. A series of asymmetric inductors with different geometries are fabricated on a standard 0.18-μxm SiGe BiCMOS process with 100 Q/cm substrate resistivity to verify the proposed model. Excellent agreement has been obtained between the measured results and the proposed model over a wide frequency range.
Fabrication and characterization of a low frequency electromagnetic energy harvester

This paper presents the fabrication and characterization of an AA size electromagnetic energy transducer based on vibration. A magnetic spring technique is used to scavenge energy from low frequency external vibration. The output of the harvester is maximized by optimizing the mass of moving and fixed magnets, coil width, coi position and load resistance through a comprehensive experimental analysis. The prototype can generate an open circuit voltage of 3.961 V and 1.18 mW average power at a load resistance of 97 Q with 9 Hz resonance frequency and 0.5 mm displacement.
Miscrostructural properties of over-doped GaN-based diluted magnetic semiconductors grown by MOCVD

We have grown transition metal (Fe, Mn) doped GaN thin films on c-oriented sapphire by metal-organic chemical vapor deposition. By varying the flow of the metal precursor, a series of samples with different ion con- centrations are synthesized. Microstructural properties are characterized by using a high-resolution transmission electron microscope. For Fe over-doped GaN samples, hexagonal Fe_3N clusters are observed with Fe_3N (0002) par- allel to GaN (0002) while for Mn over-doped GaN, hexagonal Mn_6N_(2.58) phases are observed with Mn_6N_(2.58)(0002) parallel to GaN (0002). In addition, with higher concentration ions doping into the lattice matrix, the partial lattice orientation is distorted, leading to the tilt of GaN (0002) planes. The magnetization of the Fe over-doped GaN sam- ple is increased, which is ascribed to the participation of ferromagnetic iron and Fe3N. The Mn over-doped sample displays very weak ferromagnetic behavior, which probably originates from the Mn_6N_(2.58).
Analysis and modeling of on-chip transformers under two ground conditions

Two fabricated on-chip transformers under different ground conditions (i.e., CG and IG types) have been measured to compare their different characteristics. With the aid of the electromagnetic (EM) solver, we have analyzed the differences from the electric and magnetic aspects, and different effects in these aspects can be described with the lumped capacitor and inductor from the perspective of the equivalent circuit model. A physicsbased equivalent circuit model is proposed to model transformers under different ground conditions. In addition, the simple parameter extraction procedure for the corresponding model is also provided. All the model parameters are extracted and agree with the analysis. In order to verify the model's validity and accuracy, we have compared the modeled and measured S-parameters, and an excellent agreement has been found over a broad frequency range.
A fast combination calibration of foreground and background for pipelined ADCs

This paper describes a fast digital calibration scheme for pipelined analog-to-digital converters (ADCs). The proposed method corrects the nonlinearity caused by finite opamp gain and capacitor mismatch in multiplying digital-to-analog converters (MDACs). The considered calibration technique takes the advantages of both foreground and background calibration schemes. In this combination calibration algorithm, a novel parallel background calibration with signal-shifted correlation is proposed, and its calibration cycle is very short. The details of this technique are described in the example of a 14-bit 100 Msample/s pipelined ADC. The high convergence speed of this background calibration is achieved by three means. First, a modified 1.5-bit stage is proposed in order to allow the injection of a large pseudo-random dithering without missing code. Second, before correlating the signal, it is shifted according to the input signal so that the correlation error converges quickly. Finally, the front pipeline stages are calibrated simultaneously rather than stage by stage to reduce the calibration tracking constants. Simulation results confirm that the combination calibration has a fast startup process and a short background calibration cycle of 2 x 2~(21) conversions.
A constant loop bandwidth fractional-N frequency synthesizer for GNSS receivers

A constant loop bandwidth fractional-N frequency synthesizer for portable civilian global navigation satellite system (GNSS) receivers implemented in a 130 nm 1P6M CMOS process is introduced. Via discrete working regions, the LC-VCO obtains a wide tuning range with a simple structure and small VCO gain. Spur suppression technology is proposed to minimize the phase offset introduced by PFD and charge pumps. The optimized bandwidth is maintained by an auto loop calibration module to adjust the charge pump current when the PLL output frequency changes or the temperature varies. Measurement results show that this synthesizer attains an in-band phase noise lower than -93 dBc at a 10 kHz offset and a spur less than -70 dBc; the bandwidth varies by ± 3% for all the GNSS signals. The whole synthesizer consumes 4.5 mA current from a 1 V supply, and its area (without the LO tested buffer) is 0.5 mm~2.
Influence of drain and substrate bias on the TID effect for deep submicron technology devices

This paper presents a study of the total ionization effects of a 0.18μm technology. The electrical parameters of NMOSFETs were monitored before and after irradiation with ~(60)Co at several dose levels under different drain and substrate biases. Key parameters such as off-state leakage current and threshold voltage shift were studied to reflect the ionizing radiation tolerance, and explained using a parasitic transistors model. 3D device simulation was conducted to provide a better understanding of the dependence of device characteristics on drain and substrate biases.
Influence of absorber doping in a-SiC:H/a-Si:H/a-SiGe:H solar cells

This work deals with the design evaluation and influence of absorber doping for a-Si:H/a-SiC:H/a-SiGe:H based thin-film solar cells using a two-dimensional computer aided design (TCAD) tool. Various physical parameters of the layered structure, such as doping and thickness of the absorber layer, have been studied. For reliable device simulation with realistic predictability, the device performance is evaluated by implementing necessary models (e.g., surface recombinations, thermionic field emission tunneling model for carrier transport at the heterojunction, Schokley-Read Hall recombination model, Auger recombination model, bandgap narrowing effects, doping and temperature dependent mobility model and using Fermi_Dirac statistics). A single absorber with a graded design gives an efficiency of 10.1% for 800 nm thick multiband absorption. Similarly, a tandem design shows an efficiency of 10.4% with a total absorber of thickness of 800 nm at a bandgap of 1.75 eV and 1.0 eV for the top a-Si and bottom a-SiGe mponent cells. A moderate n-doping in the absorber helps to improve the efficiency while p doping in the absorber degrades efficiency due to a decrease in the Voc (and fill factor) of the device.
An analytical model for the drain-source breakdown voltage of RF LDMOS power transistors with a Faraday shield

An analytical model for the drain-source breakdown voltage of an RF LDMOS power transistor with a Faraday shield is derived on the basis of the solution of the 2D Poisson equation in a p-type epitaxial layer, as well as an n-type drift region by means of parabolic approximation of electrostatic potential. The model captures the influence of the p-type epitaxial layer doping concentration on the breakdown voltage, compared with the previously reported model, as well as the effect of the other device parameters. The analytical model is validated by comparing with a numerical device simulation and the measured characteristics of LDMOS transistors. Based on the model, optimization of LDMOS device parameters to achieve proper trade-off between the breakdown voltage and other characteristic parameters such as on-resistance and feedback capacitance is analyzed.
A model for the chain-to-plane charge transfer in YBa_2Cu_30_(6+x)

A model for the chain-to-plane charge transfer is proposed to account for the two plateaus, at 60 K and at 90 K, of the T_c(x) characteristics of the YBa_2Cu_3O_(6+x) high-T_c superconductor. It is assumed that the number of holes transferred from a CuO chain of length I to two nearby CuO_2 sheets is proportional to l (that is, to the number of oxygen atoms in the chain), if the chain length is greater than, or equal to, a certain critical chain length, l_(cr), that is required to trigger the charge transfer process. No holes are assumed to have been transferred from chains of length l < l_(cr). The calculated T_c(x) dependence is found to be in excellent agreement with the experimentally reported T_c(x). The critical chain length parameter is estimated to be equal to l_(cr) = 11 (eleven oxygen atoms in a chain), which is a greater value than that obtained in the previously proposed model for the chain-to-plane charge transfer (l_(cr) = 4). The results obtained out of the proposed model are briefly discussed.
Discrete element modelling of the quasi-static uniaxial compression of individual infant formula agglomerates

Infant formula is usually produced in an agglomerated powder form. These agglomerates are subjected to many transient forces following their manufacture. These can be difficult to quantify experimentally because of their small magnitudes and short durations. Numerical models have the potential to address this gap in the experimental data. The objective of the research described here was to calibrate a discrete element model for these agglomerates using experimental data obtained for quasi-static loading, and to use this model to study the mechanics of the particle response in detail. The Taguchi method was previously proposed as a viable calibration approach for discrete element models. In this work, the method was assessed for calibration of the model parameters (e.g., bond stiffnesses and strengths) considering three responses: the force at failure, strain at failure and agglomerate stiffness. The Weibull moduli for the simulation results and the experimental data were almost identical following calibration and the 37% characteristic stresses were similar. An analysis of the energy terms in the model provided useful insight into the model response. The bond energy and the normal force exerted on the platens were strongly correlated, and bond breakage events coincided with the highest energy dissipation rates.
CFD-DEM simulation of spouting of corn-shaped particles

Three dimensionally coupled computational fluid dynamics (CFD) and discrete element method (DEM) were used to investigate the flow of corn-shaped particles in a cylindrical spouted bed with a conical base. The particle motion was modeled by the DEM, and the gas motion by the k-? two-equation turbulent model. A two-way coupling numerical iterative scheme was used to incorporate the effects of gas-particle interactions in terms of momentum exchange. The corn-shaped particles were constructed by a multisphere method. Drag force, contact force, Saffman lift force, Magnus lift force, and gravitational force acting on each individual particle were considered in establishing the mathematical modeling. Calculations were carried out in a cylindrical spouted bed with an inside diameter of 200 mm, a height of 700 mm, and a conical base of 60?. Comparison of simulations with experiments showed the availability of the multi-sphere method in simulating spouting action with corn-shaped particles, but it depended strongly on the number and the arrangement of the spherical elements. Gas-solid flow patterns, pressure drop, particle velocity and particle concentration at various spouting gas velocity were discussed. The results showed that particle velocity reaches a maximum at the axis and then decreases gradually along the radial direction in the whole bed. Particle concentration increases along the radial direction in the spout region but decreases in the fountain region, while it is nearly constant in the annulus region. Increasing spouting gas velocity leads to larger pressure drop, remarkably increased speed of particle moving upward or downward, but decreased particle concentration.
Noticeable positive Doppler effect on optical bistability in an N-type active Raman gain atomic system

We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region, which has been known as the positive Doppler effect on optical bistability. In addition, we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type.
Measurements of NO_2 mixing ratios with topographic target light scattering-differential optical absorption spectroscopy system and comparisons to point monitoring technique

A topographic target light scattering-differential optical absorption spectroscopy (ToTaL-DOAS) system is developed for measuring average concentrations along a known optical path and studying surface-near distributions of atmospheric trace gases. The telescope of the ToTaL-DOAS system points to targets which are located at known distances from the measurement device and illuminated by sunlight. Average concentrations with high spatial resolution can be retrieved by receiving sunlight reflected from the targets. A filed measurement of NO_2 concentration is performed with the ToTaL-DOAS system in Shijiazhuang in the autumn of 2011. The measurement data are compared with concentrations measured by the point monitoring technique at the same site. The results show that the ToTaL-DOAS system is sensitive to the variation of NO_2 concentrations along the optical path.
Computer simulation of the cluster destruction of stratospheric ozone by bromine

The interaction of (Br~-)_i(H_2O)_(50-i), 0 ≤ i ≤ 6 clusters with oxygen and ozone molecules is investigated by the method of molecular dynamics simulation. The ozone molecules as well as the bromine ions do not leave the cluster during the calculation of 25 ps. The ability of the cluster containing molecular oxygen to absorb the infrared (IR) radiation is reduced in the frequency range of 0 ≤ w ≤ 3500 cm~(-1) when the number of the bromine ions in the cluster grows. The intensity of the Raman spectrum is not changed significantly when the Br~- ions are added to the ozone-containing system. The power of the emitted IR radiation is increased when the number of bromine ions grows in the oxygen-containing system. The data obtained in this study on the IR and the Raman spectra of the water clusters that contain ozone, oxygen, and Br~- can be used to develop an investigation of the mechanisms of ozone depletion.
Highly efficient Cherenkov radiation generation in the irregular point of hollow-core photonic crystal fiber

Highly efficient Cherenkov radiation (CR) is generated by the soliton self-frequency shift (SSFS) in the irregular point of a hollow-core photonic crystal fiber (HC-PCF) in our laboratory. The impacts of pump power and wavelength on the CR are investigated, and the corresponding nonlinear processes are discussed. When the average power of the 120 fs pump pulse increases from 500 mW to 700 mW, the Raman soliton shifts from 2210 nm to 2360 nm, the output power of the CR increases by 2.3 times, the maximum output power ratio of the CR at 539 nm to that of the residual pump is calculated to be 24.32:1, the width of the output optical spectrum at the visible wavelength broadens from 35 nm to 62 nm, and the conversion efficiency η of the CR in the experiment can be above 32%.
Quantum dots-templated growth of strain-relaxed GaN on a c-plane sapphire by radio-frequency molecular beam epitaxy

We investigated the quantum dots-templated growth of a (0001) GaN film on a c-plane sapphire substrate. The growth was carried out in a radio-frequency molecular beam epitaxy system. The enlargement and coalescence of grains on the GaN quantum dots template was observed in the atom force microscopy images, as well as the more ideal surface morphology of the GaN epitaxial film on the quantum dots template compared with the one on the AlN buffer. The Ga polarity was confirmed by the reflected high energy electron diffraction patterns and the Raman spectra. The significant strain relaxation in the quantum dots-templated GaN film was calculated based on the Raman spectra and the X-ray rocking curves. Meanwhile, the threading dislocation density in the quantum dots-templated film was estimated to be 7.1 x 10~7 cm~(-2), which was significantly suppressed compared with that of the AlN-buffered GaN film. The room-temperature Hall measurement showed an electron mobility of up to 1860 cm~2/V·s in the two-dimensional electron gas at the interface of the Al_(0.25)Ga_(0.75)N/GaN heterojunction.
Efficient top-emitting white organic light emitting device with an extremely stable chromaticity and viewing-angle

In this paper, we report on the fabrication of a top-emitting electrophosphorescent p-i-n white organic light-emitting diode on the basis of a low-reflectivity Sm/Ag semi-transparent cathode together with a thickness-optimized ZnS out-coupling layer. With a 24-nm out-coupling layer, the reflectivity of the cathode is reduced to 8% at 492 nm and the mean reflectivity is 24% in the visible area. By introducing an efficient electron blocking layer tris(1-phenylpyrazolato,N,C2')iridium(III) (Ir(ppz)_3) to confine the exciton recombination area, the current efficiency and the colour stability of the device are effectively improved. A white emission with the Ir(ppz)_3 layer exhibits a maximum current efficiency of 9.8 cd/A at 8 V, and the Commission Internationale de L'Eclairage (CIE) chromaticity coordinates are almost constant during a large voltage change of 6 V-11 V. There is almost no viewing angular dependence in the spectrum when the viewing angle is no more than 45°, with a CIE_(x,y) coordinate variation of only (±0.0025, ±0.0008). Even at a large viewing angle (75°), the CIE_(x,y) coordinate change is as small as (±0.0087, ±0.0013).