Out-of-Plane Resistance Switching of 2D Bi2O2Se at the Nanoscale

Two-dimensional (2D) bismuth oxyselenide (Bi₂O₂Se) with high electron mobility shows great potential for nanoelectronics. Although the in-plane properties of Bi₂O₂Se have been widely studied, its out-of-plane electrical transport behavior remains elusive, despite its importance in fabricating devices with new functionality and high integration density. Here, the out-of-plane electrical properties of 2D Bi₂O₂Se at nanoscale are revealed by conductive atomic force microscope. This work finds that hillocks with tunable heights and sizes are formed on Bi₂O₂Se after applying a vertical electric field. Intriguingly, such hillocks are conductive in the vertical direction, resulting in a previously unknown out-of-plane resistance switching in thick Bi₂O₂Se flakes while ohmic conductive characteristic in thin ones. Furthermore, the transformation is observed from bipolar to stable unipolar conduction in thick Bi₂O₂Se flake possessing such hillocks, suggesting its potential to function as a selector in vertical devices. This work reveals the unique out-of-plane transport behavior of 2D Bi₂O₂Se, providing the basis for fabricating vertical devices based on this emerging 2D material.     

Crystallization and stability of the Bi2Sr2CaCu2Ox superconductor

A basic study of the stability of the Bi₂Sr₂CaCu₂O_x phase has been carried out in order to identify the composition and processing conditions for optimum superconducting properties. Analytical electron microscopy has been used to follow the crystallization of this phase during annealing in the solid state as well as from the melt. The crystal chemistry and phase purity is found to depend strongly on the processing conditions. Significant differences in crystallization behavior may be related to kinetic limitations of oxygen transport. The Bi₂Sr₂CaCu₂O_x phase has also been subjected to thermomechanical processing in order to improve our understanding of the deformation processes involved during fabrication of wires and tapes. It has been found that mechanical deformation can have significant effects on the microstructure of the material which in turn result in changes in superconducting properties.     

可伐合金封接用Li_2O-Al_2O_3-ZnO-SiO_2微晶玻璃研究

使用烧结法制备了Li2O-Al2O3-ZnO-SiO2微晶玻璃,利用差热分析、X射线衍射、扫描电镜等测试分析方法,对其析晶和封接特性进行了研究。结果表明,晶化温度低于800℃时,微晶玻璃主晶相为ZnAl2O4,晶体大小为0.5μm;晶化温度高于800℃时,析出晶体为ZnAl2O4和LiAlSi2O6纳米晶。该微晶玻璃具有与可伐合金相似的线膨胀系数,当加热温度达到980℃时,即可用于封接可伐合金;封接后的接口呈乳白色,外观良好,气密性和绝缘电阻均达到行业标准。     

TiO2/SiO2纳米多层膜光学特性研究

采用磁控溅射方法在玻璃基底上制备了TiO2／SiO2纳米多层膜,用椭偏仪测试了薄膜的厚度和折射率。黑体实验研究表明,TiO2／SiO2纳米多层膜在800nm～1600nm区域内对红外线的吸收较好,且吸收率随着温度的升高而增大。红外光谱研究表明, TiO2／SiO2纳米多层膜在2300cm-1～2900cm-1区域内对红外线的吸收较好。     

B2O3/SiO2比对钡硼硅系微晶玻璃性能的影响

采用固相反应法制备了高膨胀系数的钡硼硅系微晶玻璃,研究B2O3/SiO2比对钡硼硅系微晶玻璃性能的影响,并对其进行了热、力、电性能测试及XRD、SEM分析表征。结果表明:提高B2O3/SiO2比会促进液相烧结的进行,能有效降低烧结温度,并影响晶相组成;但B2O3/SiO2比过高或过低都会破坏材料的力学性能,降低抗弯强度,热膨胀系数和介电常数则随其含量增加呈减小趋势。B2O3质量分数为12%的微晶玻璃在950℃下烧结1h,有大量的方石英相析出,材料的抗弯强度最大。最终制备了具有优良介电性能的微晶玻璃,其热膨胀系数为17.87μ℃-1,抗弯强度为175MPa。     

可编程控制器在双氧水定量包装中的应用

本文从工程应用的角度详细叙述了双氧水定量包装系统的工艺要求，并讨论了控制系统的具体组成情况及方案的实施内容。     

高折射率材料吸收特性对193 nm HfO2/SiO2,Y2O3/SiO2,Al2O3/SiO2多层膜反射特性的影响

由单层HfO2，SiO2，Y2O3，Al2O3膜求出其折射率和消光系数色散曲线，据此计算出HfO2／SiO2，Y2O3／SiO2，Al2O3／SiO2的193nm多层膜反射膜曲线，并用电子束热蒸发的方法进行镀制。由分光光度计测量样品的透射率和绝对反射率，求出了各种膜层的吸收曲线。结果发现HfO2／SiO2，Al2O3／SiO2反射率实验结果与理论结果吻合得很好，而Y2O3／SiO2的理论曲线偏高。通过模拟Y2O3／SiO2的反射率曲线发现Y2O3的消光系数远大于由单层膜实验得出的结果。这说明Y2O3膜层的吸收特性与薄膜的制备工艺密切相关。     

Bi2O3添加剂对Ag2O-Nb2O5-Ta2O5介电性能的影响

以Bi2O3为添加剂，研究其不同质量比对Ag2O-Nb2O5-Ta2O5(ANT)系统介电性能的影响。用XRD衍射和SEM扫描作为技术手段，研究其不同质量比对Ag2O-Nb2O5-Ta2O5系统微观结构的影响。     

MnO2添加剂对TiO2压敏陶瓷非线性的作用

为了改善ＴｉＯ＿２低压压敏陶瓷材料的非线性，本文通过添加少量的ＭｎＯ＿２。使其非线性系数有了明显地提高。并对其原因进行了合理分析。结果表明，ＭｎＯ＿２添加剂可提高材料的晶界势垒高度，从而提高了其非线性系数。     

Effect of the Phase Composition and Local Crystal Structure on the Transport Properties of the ZrO2–Y2O3 and ZrO2–Gd2O3 Solid Solutions

Russian Microelectronics - The results of investigating the crystal structure, ionic conductivity, and local structure of the (ZrO2)1 –x(Gd2O3)x and (ZrO2)1 –x(Y2O3)x (x = 0.04, 0.08,...     

基于2N-2N2P结构的绝热非整数除电路设计

该文首先利用2N-2N2P逻辑电路结构,实现能量和信息均可恢复的绝热触发器,然后利用误差计算和偏差校正的方法,提出稳定的能量信息恢复型绝热非整数除电路设计方案,最后用计算机模拟程序检验了上述电路的正确性。     

2D grid architectures for the DFT and the 2D DFT

New algorithms for the DFT and the 2-dimensional DFT are presented. The DFT and the 2-dimensional DFT matrices can be expressed as the Kronecker product of DFT matrices of smaller dimension. These algorithms are synthesized by combining the efficient factorization of the Kronecker product of matrices with the highly hardware efficient recursive implementation of the smaller DFT matrices, to yield these algorithms. The architectures of the processors implementing these algorithms consist of 2-dimensional grid of processing elements, have temporal and spatial locality of connections. For computing the DFT of sizeN or for the 2D DFT of sizeN=N ₁ byN ₁, these algorithms require 2N multipliers and adders, take approximately computational steps for computing a transform vector, and take approximately computation steps between the computation of two successive transform vectors.     

The Effect of an N2 Additive on the GaAs Etching Rate in CF2Cl2 Plasma

Russian Microelectronics - The kinetics of GaAs etching in CF2Cl2 and CF2Cl2/N2 is investigated. It is shown that the shape of the dependences of the etching rate on the gas flow rate is determined...     

Performance Analysis of the ATM Adaptation Layer 2 (AAL2)

In this paper, we analyze the performance of AAL2 multiplexer for a continuous time Markovian arrival process. AAL2 CPS (Common Part Sublayer) packets are multiplexed in the AAL2 multiplexing queue and transmitted in the transmission queue. This tandem structure suggests that the statistics of AAL2 CPS requires at least 2 dimensional state space. Furthermore, from a network-level point of view, cell multiplexing and de-multiplexing procedures are repeated at each AAL2 switching node. That requires simple analysis model. To solve this problem, we reduce the state space by showing that the output process of multiplexing queue can be modeled with the Coxian distribution. We propose a single dimension analysis model of the CPS transmission queue. When AAL2 convey both real and non real time short packets, QoS management is a problem. This is because the QoS of real time as well as non-real time packets is measured using different metrics – delay and cell loss ratio respectively. Most previous work is concentrated around delay performance due to the real time applications getting the primary attention. From the direct comparison of delay and CLR performance, we show that delay constraint is the dominant parameter in QoS of AAL2.     

I2S2变频器的研究

文中提供了一款新颖先进的I2S2（InteIligentInductiorltypeSingle-Switch）变频器研发与设计的理论依据、主要特性、工作原理、动态分析及实验结果。该变频器系统的电路动态分析虽然是在小信号情形（条件）下进行的,但不失一般性。实验结果表明,该变频器的性能指标完全符合设计要求。     

[N_2]_2二聚物激光介质研究

理论上通过从头算法 (abinitio)计算强相互作用的N2 分子二聚物可能存在的 6种点群构型的势能曲线 ,证明N2 分子二聚物以D2h 对称群构型存在 ,且存在电偶极允许的类准分子跃迁a1B2 g →a1B3u,并计算了a1B2 g →a1B3u 跃迁的荧光谱。估算了N2 分子二聚物 ( 3 3 6 2 1nm)的小信号增益系数。利用微波 ( 2 45GHz)激励高纯氮 ,实验观测了N2 分子二聚物的系列荧光谱带 ,并利用放大自发辐射 (ASE)法测量N2 分子二聚物 ( 3 3 6 2 1nm)的小信号增益系数 ,在误差范围内与理论估算基本一致。最后从理论上估算了N2 分子二聚物激光振荡的输出功率。     

On the role of Bi2Sr2Ca1Cu2O8 and Bi2Sr2Cu1O6 on the weak links and critical currents in (Bi,Pb)2Sr2Ca2Cu2O10/Ag superconducting tapes

Silver-sheated (Bi,Pb)₂Sr₂Ca₂Cu₃O₁₀ (Bi2223) superconducting tapes with different Bi₂Sr₂CaCu₂O₈ (Bi2212) and Bi₂Sr₂Cu₁O₆ (Bi2201) concentrations, were prepared by using a two-step sintering processing and by varying cooling rates in the fabrication of the superconductors. The effect of residual Bi2212 and Bi2201 phases on weak links and critical currents of the Bi2223/Ag tapes was investigated. It was found that residual Bi2201 caused weak links at grain boundaries and limited the current-carrying capacity of the tapes. Comparatively, the residual Bi2212 phase had much less influence on both weak links and critical currents. Elimination of Bi2201 by sintering tapes at a low temperature in the final thermal cycle, or by cooling the tapes slowly, increased critical current by a factor of two. Flux pinning property was also improved by removing the residual Bi2201 phase.     

添加MnO2对ZnO-B2O3-P2O5-RnOm玻璃性能的影响

在ZnO-B<,2>O<,3>-P<,2>O<,5>-R<,n>O<,m>(R=Na、Al、Li)系玻璃中掺杂摩尔分数1%～5%的MnO<,2>,分析了MnO<,2>掺杂对玻璃的耐水性和流散性的影响,通过XRD分析了晶相的变化,通过摄像照片观察了玻璃试样受水侵蚀后表面形貌的变化.结果表明:当x(MnO<,2>)=3%时...     

In-situ monitoring of the growth of Bi2 Te2 and Sb2 Te3 films and Bi2 Te3-Sb2 Te3 superlattice using spectroscopic ellipsometry

In this work, we present in-situ monitoring of the growth of bismuth telluride (Bi₂Te₃) and antimony telluride (Sb₂Te₃) thin films as well as Bi₂ Te₃-Sb₂Te₃ superlattice using a spectroscopic ellipsometer (SE). Bi₂Te₃ and Sb₂ Te₃ films were grown by metalorganic chemical vapor deposition (MOCVD) at 350 C. A44-wavelength ellipsometer with spectral range from 404 nm to 740 nm was used in this work. The optical constants of Bi₂ Te₃ and Sb₂Te₃ at growth temperature were determined by fitting a model to the extracted in-situ SE data of optically thick Bi₂ Te₃ and Sb₂ Te₃ films. Compared to the optical constants of Bi₂ Te₃ and Sb₂ Te₃ at room temperature, significant temperature dependence was observed. Using their optical constants at growth temperature, the in-situ growth of Bi₂ Te₃ and Sb₂ Te₃ thin films were modeled and excellent fit between the experimental data and data generated from the best-fit model was obtained. In-situ growth of different Bi₂ Te₃-Sb₂ Te₃ superlattices was also monitored and modeled. The growth of Bi₂ Te₃ and Sb₂ Te₃ layers can be seen clearly in in-situ SE data. Modeling of in-situ superlattice growth shows perfect superlattice growth with an abrupt interface between the two constituent films.     

Effects of Nd2O3 and TiO2 Addition on the Microstructures and Microwave Dielectric Properties of BaO-Nd2O3-TiO2 System

The effects of Nd₂O₃ and TiO₂ addition on the microstructures and microwave dielectic properties of BaO-Nd₂O₃-TiO₂ system were investigated. BaNd₂Ti₄O₁₂ or BaNd₂Ti₅O₁₄ phases were observed for compositions based on BaO/Nd₂O₃ = 1 ratio. The compositions deviated from BaO/Nd₂O₃ = 1 ratio were composed of major phases of BaNd₂Ti₄O₁₂ or BaNd₂Ti₅O₁₄, and the compound of Nd₂O₃ and TiO₂ (Nd₂Ti₂O₇) or that of BaO and TiO₂ (BaTi₄O₉). The microstructure of ceramic with BaO·Nd₂O₃ ·4TiO₂ composition varied from spherical grains to needlelike grains with increasing sintering temperature. With increasing Nd₂O₃, the optimum sintering temperature with maximum density increased, and the dielectric constant( · _r) and quality factor(Q) decreased due to the formation of secondary phases. With increasing TiO_2/ the optimum sintering temperature and the dielectric constant decreased with increased Q value. And the temperature coefficient of resonant frequency, ·_f shifted toward positive direction. The dielectric ceramics with BaO/Nd₂O₃ = 1 showed Q values of above 2000 and dielectric constants of above 80 at 3GHz.