Nanostructured current sources based on carbon nanotubes excited by β radiation

An analysis of available and promising developments is carried out in the field of power elements based on β decay. The possible fabrication technologies are described, and the efficiency of the power sources manufactured with them is calculated. The possibility of designing a self-charging supercapacitor based on carbon nanotubes is considered with the use of ⁶³Ni and ¹⁴C isotopes, and theoretical calculation confirms the promising nature of this line of research.     

Optimization of PP− junction termination for new power devices

In this paper PP⁻-type junction termination is investigated. Based on 2D simulations, we have optimized this termination in the 1200–1400 V range under non-punch-through (NPT) and in the 400–600 V range under punch-through (PT) conditions. We have analysed the influence of the doping and the length of the lowly-doped P⁻ region on the efficiency of the termination and the influence of charges in the field oxide. These simulation results were then validated using test devices.     

Dealing With the Constraints of Optimization by O. D.E. Method

1IntrodutionIn[IJlanewmethodispresentedforfindingthelocaloptimaofthegeneralconstrainedoptimization.Thediscussionabouttheconstraintsiscontinuedbytheordinarydifferentialequationsinsection2.Itisprovedthatthesolutionsstartingfromtheneighbourhoodofacriticalpoi…     

Design and Optimization of a novel structure for efficient side-coupling of high power double-cladding fiber lasers

A novel structure for efficient side-coupling of high power double-cladding fiber lasers is presented. The maximum cou- pling efficiency of this structure is more than 90% for TM-polarization in the 1 and -1 order but is only 40% for TE- polarization. Thus, a multi-layer stair-structure is introduced and optimized by combining transmission algorithm and genetic algorithm to obtain higher coupling efficiencyηfor TE-polarization and the maximum coupling efficiency almost reaches to 70%.     

Damage Mechanism of Optical Films by High—power Laser

From several models about damage mechanis,the damage mecanism of optical films and the factors which affect the damage threshold are described experi-mentally and theoretically.Some reasonable proposals are given is this paper on how to select the high-threshold fimls.     

Optimization of parameters of double-gate sub-20 nanometers SOI CMOS transistors with architecture “without overlapping”

One of the possible approaches of an optimum choice of topological parameters of double-gate sub-20 nm CMOS transistors with a silicon-on-insulator structure and architecture that is “without an over-lapping” gate—the extended drain/source areas for minimization of short-channel effects—is discussed. The characteristics of inverters on transistors with a channel length of 16 nm for high-speed applications and applications with a low level of static power are numerically investigated in the power supply voltage range from 0.4 V up to 1 V.     

Computation of threshold function Chow parameters by graphical means †

Existing methods of computing Chow parameter tabulations for threshold functions generally employ a complex generation algorithm based on a 2-monotonic lattice. It is here shown that the Torng map is a preferable form of this lattice, and that a simple generation algorithm based on self-duality can be adopted to generate the positive canonical threshold function representatives. Translation of these representative functions into appropriate minimum-integer weights and thresholds then produces the desired standard Chow parameter tabulations. The complete procedure has little complexity and is ideally suitable for hand computation: its latter limitation is when the volume of the data becomes too great to hand-compile.     

Parameter Optimization of CdZnTe Crystal Growth Simulated by Finite Element Method

During the crystal grown by VBM, the solid/liquid interface configurations greatly influence the quality of as-grown crystals. In this paper, finite element method (FEM) was used to simulate the growth process of CdZnTe crystal. The effects of different crucible moving rates and temperature gradient of adiabatic zone on crystal growth rate and solid-liquid interface configuration were studied as well. Simulation results show that when crucible moves at the rate of about 1 mm/h, which is nearly equal to crystal growth rate, nearly flat solid/liquid interface and little variation of axial temperature gradient near it can be attained, which are well consistent with the results of experiments. CdZnTe crystal with low dislocation density can be obtained by employing appropriate crucible moving rate during the crystal growth process.     

Influence of parameters of the semiconductor–dielectric interface on the current of the guard ring of silicon photodiodes

Relationships, which determine requirements for the resistance of the inversion layer for decreasing the influence of the guard ring on the dark current and photodiode noisess and allow obtaining the specified intercoupling coefficient between photosensitive elements in multielement photodiodes, are given. It is shown that dependences of the current of the guard ring on the bias voltage and the charge on the Si–SiO₂ interface in the presence of the inversion layer satisfy the current generation model in the space-charge region of the current. The resistance of the inversion layer increase with an increase in the bias voltage in accordance with the relationship R_u ～ V^1.5.     

Thermal–mechanical behavior of the bonding wire for a power module subjected to the power cycling test

Two analytical methods were proposed in this research, coupled electro-thermal finite element (FE) analysis and thermal–mechanical FE analysis, to analyze the mechanical behavior of bonding wire of power module under cyclic power loads, and the International Electrotechnical Commission standard is adopted in conducting a power cycling test. The exterior temperature distribution was measured by an infrared thermometer. Moreover, the junction temperature is calculated from the given thermal impedance of the semiconductor chip, chip power loss, and case temperature. Subsequently, the simulated temperature distribution via electro-thermal FE analysis is compared with experimental results to validate the methodology used in the aforementioned analysis. The analysis shows compressive stress at the wire/chip interface due to CTE mismatch between the aluminum and the chip. Moreover, the major driving force contributing to the shear stress at the interface is the self-expansion of the wire bump.     

On the Optimization Problem of Spanning Tree in Fuzzy Network

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How do technologies relate to the repertoire of information sources?

This study applies “channel repertoire” to information sources. Interviews were conducted with 251 residents of Pullman, Washington, and Moscow, Idaho, in which respondents were asked to assess how interested they were in two topics (sports and what's going on in the community) along with how useful traditional media sources (tv, radio, etc.) and technologies (VCR, PC, etc.) were for information about each source. Based on a regression that controlled for demographics, separate repertoires were found for each topic. Sports had only a traditional media repertoire that consisted of tv and newspapers while what's going on in the community had a combined traditional and technology repertoire of newspapers, radios, personal computers, and cellular telephones.     

Optimization of the UTC-PD Epitaxy for Photomixing at 340 GHz

We present a method to optimize the epitaxial layer structure of an InGaAs/InP uni-traveling-carrier photo-diode (UTC-PD) for continuous THz-wave generation. The design approach used is general in that it can be applied for any target frequency while this study focuses on 340 GHz. The photodiode epitaxy is modeled and optimized using a TCAD software implementing the hydrodynamic semiconductor equations. This physical device model was found to be in good agreement with reported experimental results. It is shown that the UTC-PD can generate ~1 mW at 340 GHz by choosing the optimum absorption layer and collection layer thicknesses.     

Effects of process parameters on the synthesis and characterization of CuIn1−xGaxSe2 nanopowders produced by new modified solvothermal method

In this research, CuIn_1?xGa_xSe₂ (CIGS) nanopowders were synthesized by a new modified solvothermal process which utilized a controllable internal pressure and a stirring system during the process. The effects of process parameters on the synthesis and characterization of CIGS nanopowders were studied including reaction temperature, process time, applying internal imposed pressure, and Ga substitution with In. Chloride sources of copper, indium, and selenium powders along with gallium nitrate powder were used as precursor materials which were dissolved in triethylenetetramine as a solvent at various synthesis conditions to prepare final products in a specific autoclave. Crystal structure, morphology, and optical properties of prepared nanopowders were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX), high-resolution transmission electron microscopy (HRTEM), and diffuse-reflectance UV/vis spectroscopy (DRS). The results indicate that using both a stirring system and internal imposed pressure of 400 kPa have significant effects on the synthesis of single phase CIGS nanopowders and their crystallinity in short process time. It is also showed that samples synthesized under conditions of internal imposed pressure and long process time could form the rosette-like particles. Furthermore, optical measurements revealed that the band gap energies for prepared particles (1.05–1.38 eV) are close to those of bulk materials.     

Effect of bremsstrahlung γ-ray photons and neutrons on the parameters of indium-selenium photoconverters

The effect of Bremsstrahlung γ-ray photons and neutrons (effective energy E _eff = 8 MeV) with fluences of 10¹²–10¹³ neutron/cm² on the electrical and photoelectric parameters of layered p-n-InSe is studied for the first time. Even at the highest radiation fluence, an improvement in the current-voltage characteristics and an increase in the open-circuit voltage at an insignificant decrease in the short-circuit current are observed. Significant variations in the spectral curve of the photoresponse are not detected in general. At the same time, even the initial stage of irradiation gives rise to a pronounced degradation of the parameters of the test silicon solar cells. This fact makes it possible to recommend the photodiodes under study for use as radiation-resistant photodetectors.     

Optimization of the design flow of the system on a K64-RIO crystal manufactured using the 0.18 μm technology

In the process of developing a high-performance system on a crystal, the standard design flow proposed by CAD suppliers has been substantially changed and expanded due to the application of new design methods and the use of independently developed custom blocks. These changes made it possible to solve the following important problems: optimization of the area, with the performance at the stage of synthesis being preserved up to 20%, which improves the quality of the placement and design routability during layout designing; construction of a power grid providing a voltage drop not greater than 6.6% of the rated voltage; automation of the process of reaching the required performance and optimization of a number of layout stages yielding a decrease by a factor of 2–3 in the time of routing and improving the design quality from the standpoint of such parameters as noise immunity and performance.     

Optimization of carrier mobility in luminescence layers based on europium β-diketonates in hybrid light-emitting structures

The hole conductivity in films of three compounds, complexes based on europium β-diketonates, deposited by vacuum evaporation is studied by the time-of-flight technique. It is shown that no carrier photogeneration is observed in films under pulsed excitation with 337 nm light. The introduction of pentacene-based photogeneration layers into the samples made it possible to observe transient-current curves. It was found that a dispersive component of the transient current, associated with hole transport, is observed in a complex of europium with an auxiliary ligand based on bathophenanthroline. These data were used to determine the hole mobility. No dispersive component of the transient current was observed in complexes with an auxiliary ligand based on phenanthroline. A conclusion is made that the latter is due to the low mobility in compounds of this kind. This is attributed to a decrease in the degree of conjugation of the aromatic system, which occurs on passing from bathophenanthroline to phenanthroline.     

Analysis of electrical parameters of the glasses of the system Bix(As2S3)100−x

This work presents the results of measuring the parameters of electrical conductivity of the glasses from the system Bi_x(As₂S₃)_100−x (x=1.5, 3, 5 and 7 at%), carried out in DC and AC regimes. The values of the activation energy ΔE_σ and of the pre-exponentail factor σ₀, obtained by fitting the DC component of the conductivity as a function of temperature, served as the basis for establishing the dominant mechanism of charge transport processes in the investigated glasses. Measurements in AC regime were performed on the samples with 5 and 7 at% Bi, and analyzed in terms of the CBH (Correlated Barrier Hopping) model.