Engineered Elastomer Substrates for Guided Assembly of Complex 3D Mesostructures by Spatially Nonuniform Compressive Buckling

Approaches capable of creating 3D mesostructures in advanced materials (device‐grade semiconductors, electroactive polymers, etc.) are of increasing interest in modern materials research. A versatile set of approaches exploits transformation of planar precursors into 3D architectures through the action of compressive forces associated with release of prestrain in a supporting elastomer substrate. Although a diverse set of 3D structures can be realized in nearly any class of material in this way, all previously reported demonstrations lack the ability to vary the degree of compression imparted to different regions of the 2D precursor, thus constraining the diversity of 3D geometries. This paper presents a set of ideas in materials and mechanics in which elastomeric substrates with engineered distributions of thickness yield desired strain distributions for targeted control over resultant 3D mesostructures geometries. This approach is compatible with a broad range of advanced functional materials from device‐grade semiconductors to commercially available thin films, over length scales from tens of micrometers to several millimeters. A wide range of 3D structures can be produced in this way, some of which have direct relevance to applications in tunable optics and stretchable electronics.     

多径条件下的最优空时多用户检测

本文采用码片速率采样建立了一般的结构化空时多用户CDMA信号模型,研究了多径条件下的最优空时多用户检测的系统结构与实现,并对最优空时多用户检测的Viterbi算法给予了证明和分析。     

低载噪比下P码接收精频测量新算法及性能分析

GPS信号的P码码速率是C/A码的10倍,所以捕获时搜索相同时长的码相位需要做10倍点数的相关运算,相关运算通常用频域FFT实现,而硬件平台对FFT点数的限制使捕获得到的多普勒频率估计误差很大,因此C/A码的各种精频测量方法不能适用于低载噪比下的P码接收.本文针对P码的特性,在利用DFT相位差估计信号频率的基础上,提出了一种低载噪比下P码接收精频测量的新算法--差分相干法,并从理论和蒙特卡罗仿真两方面分析、比较了该算法与传统算法的性能,证明了本文算法能够兼顾接收机系统的实时性和精频测量精度的要求.     

食物中抗性淀粉的研究进展

在查阅的近十几年对淀粉在人肠道内消化吸收的文献基础上,综述了食物中抗性淀粉的研究进展,抗性淀粉是指不能在健康正常人小肠中消化吸收的淀粉及其降解物食中物存在抗性淀粉可分为３类,物理包埋淀粉（ＲＳＩ）抗性淀粉颗粒（ＲＳ２）和老化淀粉（ＲＳ３）其检测一般采用体外肠道模拟酶解法,影响食物中抗性淀粉形成的因素主要有淀粉自身的理化性质,食物中的其它成分,处理方式和工艺以及食物形态等,抗性淀粉属于人体无法消化吸     

A physical compact model of DG MOSFET for mixed-signal circuit applications- part I: model description

To use double-gate (DG) MOSFET for mixed-signal circuit applications, especially for circuits in which the two gates are independently driven, such as in the case of dynamic-threshold and fixed-potential-plane operations, physical compact models that are valid for all modes of operations are necessary for accurate design and analysis. Employing physically rigorous current-voltage (I-V) relationship in subthreshold and above-threshold regions as asymptotic cases, we have constructed a model that joins the two operating regions by using carrier-screening functions. We have included consistently source/drain series resistance, low drain-field mobility, and small-geometry effects of drain-induced barrier lowering (DIBL), MOS interface mobility, velocity saturation and channel-length modulation (CLM) with validation from two-dimensional (2-D) distributed simulation. All model parameters can be extracted from large-signal I-V characteristics in dc conditions with given geometrical data. Parameter extraction methods and verification from simulation are presented in Part II.     

提高甲基纤维素复合膜机械强度和热封强度的研究

本文研究了甲基纤维素复合膜的机械强度和热封强度。结果表明:用0.2％甘油增塑的甲基纤维素复合膜,其抗拉强度、直角撕裂强度、断裂伸长率和热封强度均有所改善;掺用少量硬脂酸-软脂酸(1∶1)可使甲基纤维素复合膜机械强度和热封强度降低;甲基纤维素复合膜在贮藏过程中(-18℃、0℃、20℃、40℃,相对湿度65％),其机械强度先递减后趋于稳定,但其热封强度变化不大。     

梯级水电站群调度多目标网络分析模型

研究网络分析技术在水库群调度中的应用，把多目标分层排序网络分析模型拓展到多目标梯级水电站调度的网络分析中，提出梯级水电站群调度多目标网络分析模型。结合某流域梯级水电站群优化调度实例进行模型的应用研究，结果表明，用本文模型构造的时空网络图，结构清晰，直观形象，算法效率高。     

新型应力不敏感FBG温度传感封装结构

光纤Bragg光栅（FBG）可以同时传感多个参量,但当仅需测量一个参量时,测量结果可能会受到一个或多个其他参量的影响,其中以温度和应力交叉敏感最为突出。为此,对比了其他几种应力不敏感型FBG温度传感器的优缺点,设计了一种新型的应力不敏感FBG温度传感封装结构,并通过实验验证了其温度传感性能及应力不敏感性。     

Design and Performance of Space–Time Precoder With Hybrid ARQ Transmission

Multiple-input-multiple-output (MIMO) technology can efficiently increase the system capacity in rich scattering environments without increasing the bandwidth or transmission power. The precoder for MIMO transmission is a processing technique that exploits the channel state information (CSI) by operating on the signal before transmission to effectively improve link performance. A hybrid automatic repeat request (HARQ) scheme can be incorporated with the linear precoder to ensure highly reliable communication. To fully utilize the type-I HARQ diversity gain, particularly in slow-fading channels, we propose the optimal design principle of linear precoders whose column vectors are correspondingly orthogonal to each other. In addition, the practical solution based on codebook is given in this paper. Finally, simulation results demonstrate the effectiveness of the proposed precoders in reducing the detection of bit error rate (BER) and in improving normalized throughput.