Modification of the Hybridization Gap by Twisted Stacking of Quintuple Layers in a Three-Dimensional Topological Insulator Thin Film

Twisting the stacking of layered materials leads to rich new physics. A three-dimensional topological insulator film hosts two-dimensional gapless Dirac electrons on top and bottom surfaces, which, when the film is below some critical thickness, will hybridize and open a gap in the surface state structure. The hybridization gap can be tuned by various parameters such as film thickness and inversion symmetry, according to the literature. The three-dimensional strong topological insulator Bi(Sb)Se(Te) family has layered structures composed of quintuple layers(QLs) stacked together by van der Waals interaction. Here we successfully grow twistedly stacked Sb_2Te_3 QLs and investigate the effect of twist angels on the hybridization gaps below the thickness limit. It is found that the hybridization gap can be tuned for films of three QLs, which may lead to quantum spin Hall states.Signatures of gap-closing are found in 3-QL films. The successful in situ application of this approach opens a new route to search for exotic physics in topological insulators.

THREE-DIMENSIONAL ANALYSIS OF FUNCTIONALLY GRADED PLATE BASED ON THE HAAR WAVELET METHOD

A three-dimensional analysis of a simply-supported functionally graded rectangular plate with an arbitrary distribution of material properties is made using a simple and effective method based on the Haar wavelet. With good features in treating singularities, Haar series solution converges rapidly for arbitrary distributions, especially for the case where the material properties change rapidly in some regions. Through numerical examples the influences of the ratio of material constants on the top and bottom surfaces and different material gradient distributions on the structural response of the plate to mechanical stimuli are studied.

Three-dimensional elasticity solutions for bending of generally supported thick functionally graded plates

Three-dimensional elasticity solutions for static bending of thick functionally graded plates are presented using a hybrid semi-analytical approach-the state-space based differential quadrature method （SSDQM）. The plate is generally supported at four edges for which the two-way differential quadrature method is used to solve the in-plane variations of the stress and displacement fields numerically. An approximate laminate model （ALM） is exploited to reduce the inhomogeneous plate into a multi-layered laminate, thus applying the state space method to solve analytically in the thickness direction. Both the convergence properties of SSDQM and ALM are examined. The SSDQM is validated by comparing the numerical results with the exact solutions reported in the literature. As an example, the Mori-Tanaka model is used to predict the effective bulk and shear moduli. Effects of gradient index and aspect ratios on the bending behavior of functionally graded thick plates are investigated.

Three-dimensional channel flow of second grade fluid in rotating frame

An analysis is performed for the hydromagnetic second grade fluid flow between two horizontal plates in a rotating system in the presence of a magnetic field. The lower sheet is considered to be a stretching sheet, and the upper sheet is a porous solid plate. By suitable transformations, the equations of conservation of mass and momentum are reduced to a system of coupled non-linear ordinary differential equations. A series of solutions to this coupled non-linear system are obtained by a powerful analytic technique, i.e., the homotopy analysis method （HAM）. The results are presented with graphs. The effects of non-dimensional parameters R, A, M2, a, and K2 on the velocity field are discussed in detail.

Three-dimensional Analysis of Functionally Graded Piezoelectric Plate with Arbitrarily Distributed Material Properties

An orthotropic functionally graded piezoelectric rectangular plate with arbitrarily distributed material properties was studied, which is simply supported and grounded（electrically） on its four lateral edges. The state equations of the functionally graded piezoelectric material were obtained using the state-space approach, and a Peano-Baker series solution was obtained for the coupled electroelastic fi elds of the functionally graded piezoelectric plate subjected to mechanical and electric loading on its upper and lower surfaces. The influence of different distributions of material properties on the structural response of the plate was studied using the obtained solutions.

An optimal stacking order for mid-bond testing cost reduction of 3D IC

In order to solve the problem that the testing cost of the three-dimensional integrated circuit(3D IC)is too high,an optimal stacking order scheme is proposed to reduce the mid-bond test cost.A new testing model is built with the general consideration of both the test time for automatic test equipment(ATE)and manufacturing failure factors.An algorithm for testing cost and testing order optimization is proposed,and the minimum testing cost and optimized stacking order can be carried out by taking testing bandwidth and testing power as constraints.To prove the influence of the optimal stacking order on testing costs,two baselines stacked in sequential either in pyramid type or in inverted pyramid type are compared.Based on the benchmarks from ITC 02,experimental results show that for a 5-layer 3D IC,under different constraints,the optimal stacking order can reduce the test costs on average by 13%and 62%,respectively,compared to the pyramid type and inverted pyramid type.Furthermore,with the increase of the stack size,the test costs of the optimized stack order can be decreased.

A Novel Hydrogen-bonded Three-dimensional Network Complex Containing Nickel

A novel complex, (H 3O) 2[Ni(2,6-pydc) 2]·2H 2O was synthesized in an aqueous solution and characterized by means of single-crystal X-ray diffraction, elemental analyses and IR spectra. The X-ray structural analysis revealed that the novel compound forms three-dimensional(3D) networks by both π-π stacking and hydrogen-bonding interactions. The crystal data for the complex are a=13.853(3) nm, b=9.6892(19) nm, c=13.732(3) nm, α=90.00°, β=115.52(3)°, γ=90.00°, Z=3, R 1=0.0786, wR 2=0.1522.

Hydrogen-bonded Three-Dimensional Networks Encapsulating One-dimensional Covalent Chains: [Cu(3-ampy)(H_2O)_4](SO_4)·(H_2O) (3-ampy = 3-Aminopyridine)

A three-dimensional complex [Cu（3-ampy）（HEO）4]（SO4）·（H2O） （3-ampy = 3-amino- pyridine） has been synthesized. Crystallographic data： C5H16CuN2O9S, Mr = 343.80, triclinic, space group P1, a = 7.675（2）, b = 8.225（3）, c = 10.845（3）A, α= 86.996（4）, β = 76.292（4）, γ= 68.890（4）°, V = 620.0（3）A^3, Z = 2, Dc = 1.841 g/cm^3, F（000） = 354 and μ = 1.971 mm^-1. The structure was refined to R = 0.0269 and wR = 0.0659 for 1838 observed reflections （I 〉 2a（/））. The structure consists of [Cu（3-ampy）（H2O）4]^2＋ cations, SO4^2- anions and lattice water molecules. 3-Ampy acting as a bidentate bridging ligand generates a 1D covalent chain. A supramolecular 2D framework is formed through π-π stacking of pyridine rings. The lattice water molecules and SO4^2- anions are located between the adjacent 2D frameworks. The hydrogen bonding interactions from lattice water molecules and SO4^2- anions to coordinate water extend the 2D framework into a 3D network.

THREE-DIMENSIONAL STATIC ANALYSES FOR FGM PLATES WITH MEDIUM COMPONENTS AND DIFFERENT NET STRUCTURES

A new microelement method for the analyses of functionally graded structures was proposed. The key of this method is the maneuverable combination of two kinds of elements. Firstly, the macro elements are divided from the functionally graded material structures by the normal finite elements. In order to reflect the functionally graded distributions of materials and the microconstitutions in each macro-element, the microelement method sets up the dense microelements in every macro-element, and translates nodes to the same as the normal finite elements by the degrees of freedom of all microelemental the compatibility conditions. This microelement method can fully reflect the micro constitutions and different components of materials, and its computational elements are the same as the normal finite elements, so it is an effective numerical method for the analyses of the functionally graded material structures. The three-dimensional analyses of functionally graded plates with medium components and different micro net structures are given by using the microelement method in this paper. The differences of the stress contour in the plane of functionally graded plates with different net microstructures are especially given in this paper.

A Three-Dimensional Size-Dependent Layered Model for Simply-Supported and Functionally Graded Magnetoelectroelastic Plates

A three-dimensional size-dependent layered model for simply-supported and func- tionally graded magnetoelectroelastic plates is presented based on the modified couple-stress theory. The functionally graded material is assumed to be exponential in the thickness direc- tion of the plate. The final governing equations are reduced to an eigensystem by expressing the extended displacements in terms of two-dimensional Fourier series. Using the propagator matrix method, the exact solutions of the magnetic, electric and mechanical fields of sandwich nanoplates with couple-stress effect and under the surface loads are derived. Numerical examples for two functionally graded sandwich plates made of piezoelectric BaTiO3 and magnetostrictive CoFe2O4 materials are presented to demonstrate the effect of the functional gradient factor and material length-scale parameter on the induced fields. The exact solutions presented in this work can also serve as benchmarks to various numerical methods for analyzing the size-dependent features in layered systems.

右江盆地三叠纪岩层极低级变质作用及地球动力学意义

右江盆地三叠纪槽盆相浊流沉积岩系遭受过区域极低级变质作用。依据地质观察和伊利石结晶度、绿泥石－云母堆垛集合体、标志性粘土矿物及白云母（伊利石）ｂ０参数测定资料，阐述了泥质岩石的成岩变质作用经浅层（近）变质作用到浅变质作用的转换特征。变质温度区间为１５０—３５０℃，低压类型，具高地温梯度（４０—４３℃／ｋｍ）。变质级及亚带总体与地层时代及岩层在地层柱中的位置有耦合关系，而与区域变形强度无关。最后指出区域极低级变质作用是印支－燕山构造旋回早期及区域变形前的地质事件，属于地壳伸展构造背景下右江边缘型盆地内部的埋藏型变质作用。

右江中生代极低级变质带的变质变形过程

右江中生代三叠系槽盆相浊流沉积岩系遭受了区域强烈变形和极低级变质作用，伊利石结晶度指数为０．３３１°～０．２６５°△２θ，属于浅层或近变质带；在野外和光学显微镜观察基础上，运用Ｘ射线衍射、透射电镜及电子探针等现代测试技术，对绿泥石－白云母堆垛集合体、细粒基质层状硅酸盐矿物的化学成分及结构进行了详细研究，指出绿泥石－白云母堆垛的碎屑成因及母矿物的变质过程；

水煤浆粒度级配模型和实践的研究进展

水煤浆是一种煤基液态燃料,具有与燃料油相似的物理特性,是煤炭高效清洁利用的一个重要途径,可显著减少NOx和SO2的排放。目前我国水煤浆需求量已突破2.5亿t/a,粒度级配作为影响水煤浆浓度的重要因素,使不同大小的煤颗粒互相填充,尽可能减少空隙,提高颗粒的堆积效率和水煤浆浓度。分析了粒度级配对水煤浆的影响,指出在水煤浆制浆过程中,粒度级配只涉及物理破碎和研磨,能耗相对较小,显著提升浓度,具有广泛的适用性和经济性。论述了近年来新发展的粒度级配理论和模型,特别是隔层堆积理论和分形级配理论,并给出了具体的计算方法和公式,以及假设和适用性。通过举例给出近年来隔层堆积理论的发展和应用,以及对于堆积效率的具体评价;分析了分形级配理论的可行性和新的研究进展,以及在指导烟煤和褐煤级配时的应用效果;给出了三峰级配的工艺流程、级配方案和工业实践案例。在粒度级配提高水煤浆浓度的基础理论和应用实践方面,国内外学者已做大量工作。但在具体的理论细节方面,如隔层堆积对于任意粒度分布的简化计算、分形级配的拟合精度以及三峰级配的粒度堆积评价还需更深入的研究。在级配理论应用于实践过程中,基础理论和工业实践的结合还有待于进一步提高。在粒度级配基础上,建议引入内在水分等影响因素,建立跨煤种的预测模型。

高压径向均压绝缘堆设计

以形成线储能结合脉冲压缩方式产生数MV高压输出,是脉冲功率系统中常见的技术途径,其中绝缘堆是该类装置工程成败的关键。分析了几种径向均压绝缘堆的均压机制,基于静电场分析程序对径向均压绝缘堆结构进行了优化设计,给出了径向电阻的设计方法。研究表明:采用均压环且均压环与径向电阻电气接触的绝缘堆结构可以获得较均匀的径向电场分布,而径向电阻是绝缘堆设计的关键。在有效作用时间100ns的4.5MV加载电压下,优化设计的绝缘堆阴极三相点电场控制在25kV/cm,Martin电场约120kV/cm,低于理论击穿值。

X光二极管实验平台初步设计

采用Marx发生器结合水介质同轴线设计了高压脉冲功率源,在X射线二极管负载上可产生数MV高压输出。通过电压波过程分析,给出了在负载上获得最大电压输出条件下的形成线、传输线的阻抗设计原则。通过集中参数电路模型分析,给出了一定预脉冲幅值下形成线、传输线电长度及中储设计原则。结合水介质正极性耐压Martin经验公式进行绝缘设计,二极管采用径向均压绝缘堆结构,给出了整个装置初步方案设计。基于Pspice的全系统电路模拟表明:当中储运行电压为2.6MV时,对3Ω形成线充电电压为3.3MV,并最终在40Ω负载上获得4MV电压输出,且充电过程中负载脉冲幅值约为形成线充电电压的1.2%,在现有条件下,该平台设计指标能够满足实验预期。

向IPv6网络演进的技术路线和方案分析

介绍了向IPv6网络演进的3种技术,即双栈、隧道和翻译技术,以及当前过渡技术的研究热点,包括6rd,CGN和IVI翻译技术,分析了不同过渡方案的应用。

滨5区块井间地震资料处理及效果

滨5区块的沙三段主要含油层系为砂砾岩体岩性油藏,砂体横向变化快、层间物性差异大,储层描述难度大,由于常规三维地震资料分辨能力难以满足砂体精细描述的要求,因此在该区实施了高分辨率的井间地震技术来提高砂体描述精度。针对原始资料特点,利用高精度层析成像和基于映射叠加的叠前深度偏移成像等关键处理技术获取了高分辨率的偏移成像剖面,对井间地震成果剖面进行解释,落实了井间低序级断层和储层横向连通性,建立了更加精细的油藏地质模型,提高了储层描述精度。

ARM9 S3C2410中断程序的堆栈图解析方法

针对ARM9 S3C2410的汇编语言中断程序难以理解的问题,提出用堆栈图对中断程序进行解析的方法。在详细论述S3C2410的中断管理机制基础上,给出中断处理的三级跳转图。分析三级跳转的设计思想,讨论利用异常跳转表、宏指令表、异常向量表、中断向量表实现跳转的方式。并用堆栈图详细解析跳转程序,给出中断服务程序写入中断向量表的汇编语言方式与C语言方式。分析结果表明,堆栈图方法能够详细清楚地呈现中断程序的设计思想,是一种行之有效的汇编语言中断程序的解析方法。

基于以太网交换机的IPv4/IPv6双协议栈研究

首先介绍双协议栈的工作原理及相关应用模型,然后分析IPv4/IPv6双协议栈的工作方式,最后以电信级以太网交换机为平台进行具体实现和验证。

Vertically Integrated Electronics: New Opportunities from Emerging Materials and Devices

Vertical three-dimensional(3D)integration is a highly attractive strategy to integrate a large number of transistor devices per unit area.This approach has emerged to accommodate the higher demand of data processing capability and to circumvent the scaling limitation.A huge number of research efforts have been attempted to demonstrate vertically stacked electronics in the last two decades.In this review,we revisit materials and devices for the vertically integrated electronics with an emphasis on the emerging semiconductor materials that can be processable by bottom-up fabrication methods,which are suitable for future flexible and wearable electronics.The vertically stacked integrated circuits are reviewed based on the semiconductor materials:organic semiconductors,carbon nanotubes,metal oxide semiconductors,and atomically thin two-dimensional materials including transi-tion metal dichalcogenides.The features,device performance,and fabrication methods for 3D integration of the transistor based on each semiconductor are discussed.Moreover,we highlight recent advances that can be important milestones in the vertically integrated elec-tronics including advanced integrated circuits,sensors,and display systems.There are remaining challenges to overcome;however,we believe that the vertical 3D integration based on emerging semiconductor materials and devices can be a promising strategy for future electronics.