Reverse Converters for a New Moduli Set {2<Superscript>2n</Superscript> − 1, 2<Superscript>n</Superscript>, 2<Superscript>2n</Superscript> + 1}

A new moduli set derived from a recently proposed four moduli set is considered, in this paper. The problem of reverse conversion has been considered, and it is shown that the proposed moduli set needs less reverse conversion time and area requirements than the converter for the four moduli set from which it is derived. The proposed moduli set is also compared with two other well-known three moduli sets and for realizing the same dynamic range regarding the area and conversion times of the residue number system (RNS)-to-binary converters.     

仅2mm&#215;2mm的高性能微控制器

小型微控制器C8051T606是低成本的8位混合信号微控制器,针对可编程嵌入系统,在精巧的2mm&#215;2mm封装中提供超高的功能密度。高性能的CPU能提供较大的设计弹性,集成的电压监测和精密振荡器让T606更适用于要求精简空间的应用,如便携式消费性电子产品及周边、网关和LED照明等。     

Photoelectric properties of surface-barrier structures based on Zn<Subscript>2−2<Emphasis Type="Italic">x</Emphasis></Subscript>Cu<Subscript>x</Subscript>In<Subscript>x</Subscript>Se<Subscript>2</Subscript> films obtained by selenization

p-Zn_2?2xCu_xIn_xSe₂ (ZCIS) polycrystalline films 1–2 ¼m thick have been obtained by selenization. Photosensitive surface-barrier In/p-ZCIS structures are fabricated based on the films. The spectra of relative quantum efficiency of the structures obtained by selenization of the initial ZnSe/(Cu-In) and (Zn-Cu-In) films are examined. The optical band gap of the Zn_2?2xCu_xIn_xSe₂ films is determined. Conclusions are reached on the prospects for the use of the obtained films as broadband photoconverters of natural optical radiation.     

Photoluminescence and excitation features of Nd<Superscript>3+</Superscript> ions in (La<Subscript>0.97</Subscript>Nd<Subscript>0.03</Subscript>)<Subscript>2</Subscript>S<Subscript>3</Subscript> · 2Ga<Subscript>2</Subscript>O<Subscript>3</Subscript> glasses

A combined study of the spectral photoluminescence distribution and excitation spectra of photoluminescence in La₂S₃ · 2Ga₂O₃ and (La_0.97Nd_0.03)₂S₃ · 2Ga₂O₃ glasses, along with the study of the transmission spectra of these glasses, was carried out. The radiative channel was ascertained to be the main channel for the energy transfer from the host matrix to the Nd³⁺ ions upon excitation of the glasses with light at a wavelength of the fundamental absorption band. Oxygen centers with the level E _c -2.0 eV act as sensitizing agents. The structural disordering of the glass host increases the variance in the magnitude of splitting of the multiplet levels from the 4f electronic states of the Nd³⁺ ion. This promotes nonradiative relaxation of the electrons from excited states to the laser ⁴F_3/2 level. The (La_0.97Nd_0.03)₂S₃ · 2Ga₂O₃ glasses can be considered as promising laser materials for obtaining the stimulated emission of radiation of Nd³⁺ ions under an optical pump in the range of the fundamental absorption band of the glass.     

Free-Standing β-Ga<Subscript>2</Subscript>O<Subscript>3</Subscript> Thin Diaphragms

Free-standing, very thin, single-crystal β-gallium oxide (β-Ga₂O₃) diaphragms have been constructed and their dynamical mechanical properties characterized by noncontact, noninvasive optical measurements harnessing the multimode nanomechanical resonances of these suspended nanostructures. We synthesized single-crystal β-Ga₂O₃ using low-pressure chemical vapor deposition (LPCVD) on a 3C-SiC epilayer grown on Si substrate at temperature of 950°C for 1.5 h. The synthesized single-crystal nanoflakes had widths of ～ 2 μm to 30 μm and thicknesses of ～ 20 nm to 140 nm, from which we fabricated free-standing circular drumhead β-Ga₂O₃ diaphragms with thicknesses of ～ 23 nm to 73 nm and diameters of ～ 3.2 μm and ～ 5.2 μm using a dry stamp-transfer technique. Based on measurements of multiple flexural-mode mechanical resonances using ultrasensitive laser interferometric detection and performing thermal annealing at 250°C for 1.5 h, we quantified the effects of annealing and adsorption of atmospheric gas molecules on the resonant characteristics of the diaphragms. Furthermore, we studied the effects of structural nonidealities on these free-standing β-Ga₂O₃ nanoscale diaphragms. We present extensive characterization of the mechanical and optical properties of free-standing β-Ga₂O₃ diaphragms, paving the way for realization of resonant transducers using such nanomechanical structures for use in applications including gas sensing and ultraviolet radiation detection.     

Conductivity of Ga<Subscript>2</Subscript>O<Subscript>3</Subscript>–GaAs Heterojunctions

The effect of annealing in argon at temperatures of T_an = 700–900°C on the I–V characteristics of metal–Ga₂O₃–GaAs structures is investigated. Samples are prepared by the thermal deposition of Ga₂O₃ powder onto GaAs wafers with a donor concentration of N _d = 2 × 10¹⁶ cm^–3. To measure theI–V characteristics, V/Ni metal electrodes are deposited: the upper electrode (gate) is formed on the Ga₂O₃ film through masks with an area of S _k = 1.04 × 10^–2 cm² and the lower electrode in the form of a continuous metallic film is deposited onto GaAs. After annealing in argon at T_an ≥ 700°C, the Ga₂O₃-n-GaAs structures acquire the properties of isotype n-heterojunctions. It is demonstrated that the conductivity of the structures at positive gate potentials is determined by the thermionic emission from GaAs to Ga₂O₃. Under negative biases, current growth with an increase in the voltage and temperature is caused by field-assisted thermal emission in gallium arsenide. In the range of high electric fields, electron phonon-assisted tunneling through the top of the potential barrier is dominant. High-temperature annealing does not change the electron density in the oxide film, but affects the energy density of surface states at the GaAs–Ga₂O₃ interface.     

Thermal Conductivity Reduction in CoSb<Subscript>3</Subscript>–CeO<Subscript>2</Subscript> Nanocomposites

CoSb₃ + x% CeO₂ nanocomposites (x = 1, 3, 5) were synthesized by ball-milling and spark plasma sintering. Scanning electron microscopy showed that some CeO₂ nano-inclusions sit at the boundaries of CoSb₃ grains. These inclusions also reduce the sizes of the CoSb₃ grains and crystallites by inhibiting their growth during sintering. Hall-effect measurements show that the CeO₂ inclusions modify the charge-carrier concentration in CoSb₃. The variations of the electrical resistivity for the 1% and 3% CeO₂ samples can at least partially be attributed to these modifications of the carrier concentration. Nonetheless, the resistivity increase in the 5% CeO₂ sample can unambiguously be ascribed to the presence of the CeO₂ inclusions. Thermal conductivity is systematically reduced (by more than 15% at 300 K) upon CeO₂ addition. Phonon diffusion by the increased number of CoSb₃ grain boundaries is one of the mechanisms involved in this reduction.     

Low-Temperature,Strong SiO<Subscript>2</Subscript>-SiO<Subscript>2</Subscript> Covalent Wafer Bonding for III–V Compound Semiconductors-to-Silicon Photonic Integrated Circuits

We report a low-temperature process for covalent bonding of thermal SiO₂ to plasma-enhanced chemical vapor deposited (PECVD) SiO₂ for Si-compound semiconductor integration. A record-thin interfacial oxide layer of 60 nm demonstrates sufficient capability for gas byproduct diffusion and absorption, leading to a high surface energy of 2.65 J/m² after a 2-h 300°C anneal. O₂ plasma treatment and surface chemistry optimization in dilute hydrofluoric (HF) solution and NH₄OH vapor efficiently suppress the small-size interfacial void density down to 2 voids/cm², dramatically increasing the wafer-bonded device yield. Bonding-induced strain, as determined by x-ray diffraction measurements, is negligible. The demonstration of a 50 mm InP epitaxial layer transferred to a silicon-on-insulator (SOI) substrate shows the promise of the method for wafer-scale applications.     

Planar defects and double-domain epitaxy in epitaxial YSi<Subscript>2−x</Subscript> and ErSi<Subscript>2−x</Subscript> thin films on Si substrates

Interfacial reactions of Y and Er thin films on both (111)Si and (001)Si have been studied by transmission electron microscopy (TEM). Epitaxial rare-earth (RE) silicide films were grown on (111)Si. Planar defects, identified to be stacking faults on planes with 1/6 displacement vectors, were formed as a result of the coalescence of epitaxial silicide islands. Double-domain epitaxy was found to form in RE silicides on (001)Si samples resulting from a large lattice mismatch along one direction and symmetry conditions at the silicide/(001)Si interfaces. The orientation relationships are [0001]RESi_2−x// Si, RESi_2−x//(001)Si and [0001]RESi_2−x/ Si, RESi_2−x//(001)Si. The density of staking faults in (111) samples and the domain size in (001) samples were found to decrease and increase with annealing temperature, respectively.     

2&#215;150WD类功率放大器TDA8950

TDA8950是NXP半导体公司推出的新型高效率D类音频功率放大器,在4Ω负载时典型输出功率为2&#215;150W。     

Photoluminescence in Spray Pyrolysis Deposited β-In<Subscript>2</Subscript>S<Subscript>3</Subscript> Thin Films

Spray pyrolysis deposited In₂S₃ thin films exhibit two prominent photoluminescent emissions. One of the emissions is green in color and centered at around ～ 540 nm and the other is centered at around ～ 690 nm and is red in color. The intensity of the green emission decreases when the films are subjected to annealing in air or vacuum. The intensity of red emission increases when films are air annealed and decreases when vacuum annealed. Vacuum annealing leads to an increase in work function whereas air annealing leads to a decrease in work function for this thin film system relative to the as deposited films indicating changes in space charge regions. Surface photovoltage analysis using a Kelvin probe leads to the conclusion that inversion of band bending occurs as a result of annealing. Correlating surface contact potential measurements using a Kelvin probe, x-ray photoelectron spectroscopy and photoluminescence, we conclude that the surface passivation plays a critical role in controlling the photoluminescence from the spray pyrolysis deposited for In₂S₃ thin films.     

2&#183;14当情人节撞上春节

情人节与春节，一个是与恋人缠绵的浪漫时光，一个是与家人团聚的温馨时刻，原本各得其所。谁知时间的车轱辘一转到2010年，情人节与大年初一“撞”了个满怀。而如此的巧合，下一次将在2048年。不过，按照我们“礼尚往来”的优良传统，不管是情人节也好，春节也女子，不管是情人也好，爱人也好，这天，你总得有点像样的礼物才好。     

Impact of <Emphasis Type="Italic">In Situ</Emphasis> Generated Ag<Subscript>2</Subscript>Te Nanoparticles on the Microstructure and Thermoelectric Properties of AgSbTe<Subscript>2</Subscript> Compounds

A series of ternary (Ag₂Te) _x (Sb₂Te₃)_100−x (x = 44 to 54) bulk materials with in situ generated Ag₂Te nanoparticles were prepared from high-purity elements by combining the melt-quench technique with the spark plasma sintering technique. The influence of the Ag₂Te nanoparticles on the thermoelectric transport properties, and the mechanism of nanoparticle formation were investigated. With increasing x, the concentration of the Ag₂Te nanoparticles increased monotonically, but their diameter remained nearly unchanged. Due to the possible carrier energy filtering effect caused by the Ag₂Te nanoparticle inclusions, the Seebeck coefficient of the sample with x = 50 was two times higher than that of the sample prepared by the melting method. Moreover, notable scattering of mid-to-long wavelength phonons arising from the evenly distributed Ag₂Te nanoparticles led to a large reduction of the lattice thermal conductivity. All these effects led to the enhancement of the ZT value of the x = 50 sample (AgSbTe₂) compared with the single-phase sample (x = 44).     

Optical properties of (CuInSe<Subscript>2</Subscript>)<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>(2MnSe)<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> alloys

The transmittance spectra of (CuInSe₂)_{1 − x} (2MnSe) _x alloy crystals grown by the Bridgman method are studied in the temperature range from 10 to 300 K. For these materials, the band gap and its temperature dependence are determined. It is shown that the band gap decreases with increasing temperature. The dependences of the band gap of the (CuInSe₂)_{1 − x} (2MnSe) _x alloys on the composition parameter x are plotted.     

First-principles study of GaAs(0 0 1)-β2(2 × 4) surface oxidation

Oxygen atom adsorption on GaAs(0 0 1)-β2(2 × 4) during initial surface oxidation is studied by density functional theory (DFT). The results show that one or two oxygen atom adsorption at back-bond sites satisfy the bond saturation conditions leading to no effect on the surface gap states. However, for an oxygen replacement of an As dimer atom at trough site or row site As dimer atoms, an As-As bond is broken. Mid gap states are produced leading to the Fermi level pining due to the unsaturated As dangling bonds.     

Catalyst-Free Direct Vapor-Phase Growth of Hexagonal ZnO Nanowires on <Emphasis>α</Emphasis>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript>

The evolution of ZnO nanowires has been studied under supersaturation of Zn metal species with and without a ZnO thin-film buffer layer on α-Al₂O₃ deposited by the pulsed laser ablation technique. The nanowires had diameters in the range of 30 nm to 50 nm and lengths in the range of 5 μm to 10 μm with clear hexagonal shape and [000[`1]] [000\bar{1}] , [10[`1]1] [10\bar{1}1] , and [10[`1]0] [10\bar{1}0] facets. X-ray diffraction (XRD) measurements indicated crystalline properties for the ZnO nanostructures grown on pulsed laser deposition (PLD) ZnO nucleation layers. The optical properties were analyzed by photoluminescence (PL) and cathodoluminescence (CL) measurements. The ZnO nanowires were found to emit strong ultraviolet (UV) light at 386 nm and weak green emission as observed by PL measurements. The stoichiometry of Zn and O was found to be close to 1 by x-ray photoelectron spectroscopy (XPS) measurements. The process-dependent growth properties of ZnO nanostructures can be harnessed for future development of nanoelectronic components including optically pumped lasers, optical modulators, detectors, electron emitters, and gas sensors.     

Mössbauer and magnetic studies of the ternary compound FeIn<Subscript>2</Subscript>Se<Subscript>4</Subscript>

Single crystals of the ternary compound FeIn₂Se₄ are grown by directional crystallization of the melt. The composition and structure of the single crystals are determined. The local states of iron ions in this compound are studied by nuclear γ-resonance spectroscopy in transmission configuration. The temperature and field dependences of a specific magnetic moment for the ternary compound FeIn₂Se₄ are measured in the temperature range 4–310 K in magnetic fields of 0–140 kOe. The reasons and mechanisms for magnetic state formation in single crystals of the obtained compound are discussed.     

快乐&#215;2——I Feel Good！

梦幻般的场景，黑色的游戏手柄，像珍贵的珠宝一般，在她手里。她骄傲地接受着男生们的注视，仿佛待嫁的公主，矜持地挑选着下一个舞伴，当然，只有这一曲…… 时间仿佛已经停在快门按下的那一刻，而脑子里的场景此刻却在加倍涌出。无论是天性爱玩的王蓉，还是让所有人拭目以待的PS3，这个组合就像催化剂一样，让每个看似虚无的游戏场景都化为现实。     

Formation and optical properties of CuInSe<Subscript>2<Emphasis Type="Italic">x</Emphasis></Subscript>Te<Subscript>2(1−<Emphasis Type="Italic">x</Emphasis>)</Subscript> nanoparticles in a silicate glass matrix

Glasses containing nanoparticles of semiconductor CuInSe_2xTe_2(1?x) compounds (0≤x≤1) were fabricated by high-temperature melting of the mixtures of the glass-forming components and the corresponding compounds. Particles of average size 15–30 nm, whose characteristics were similar for compounds with different x, were formed. Optical absorption of the glasses near the fundamental absorption edge in the near-infrared and visible regions of the spectrum was studied, as well as the effect of additional heat treatment of glasses on their optical properties. The nature of the observed changes in the spectra with varying compound composition (the [Se]/[Te] ratio) was related to the possible transformations of the crystalline structure of nanoparticles.