Static-noise margin analysis of MOS SRAM cells

The stability of both resistor-load (R-load) and full-CMOS SRAM cells is investigated analytically as well as by simulation. Explicit analytic expressions for the static-noise margin (SNM) as a function of device parameters and supply voltage are derived. The expressions are useful in predicting the effect of parameter changes on the stability as well as in optimizing the design of SRAM cells. An easy-to-use SNM simulation method is presented, the results of which are in good agreement with the results predicted by the analytic SNM expressions. It is further concluded that full-CMOS cells are much more stable than R-local cells at a low supply voltage.     

Operation of a Medium-Voltage Drive Under Faulty Conditions

This paper presents a method for operating cascaded multilevel inverters when one or more power cells are damaged. The method is based on the use of additional switches in the power circuit to bypass the faulty cell. To control the cells, the angle of phase shifting in the carrier signals is modified according to the number of operating cells, to minimize the load voltage distortion, when the inverter operates in failure mode. The reference signals of the pulsewidth-modulation modulators are also modified to increase the output voltage. Simulation and experimental results show the effectiveness of this method, which significantly increases the reliability of the drive.     

基于形态学特征的细胞活性无损检测新方法研究

利用正常细胞、凋亡细胞和坏死细胞在形态学特征上的差异,使用圆度和半径比率2个物理量来表征细胞活性状态,并运用微分干涉相衬（DIC）显微镜获得待测细胞图像,结合图像识别软件,提出了一种基于细胞形态学特征的细胞活性无损检测方法,测得了与细胞活性相关的有关参数。该方法应用于氨乙酰丙酸（ALA）的光动力疗法（PDT）后白血病细胞的活性检测得出的结论与使用四甲基偶氮唑盐比色（MTT）法检测得出的结论基本一致。该方法也可检测出死亡细胞中凋亡、坏死的比例;在对细胞测试的过程不需对细胞进行染色等预处理,是一种无损检测方法。     

一种新的测量扭曲向列相液晶盒盒厚和扭曲角的Stokes矢量法

提出了一种新的测量扭曲向列相液晶盒盒厚和扭曲角的Stokes矢量法。根据Jones矩阵推导出了Stokes矢量与液晶盒参数的关系,其原理是通过确定经过液晶盒之后偏振光的偏振特性来求解液晶盒盒厚和扭曲角。该方法在测量一个Stokes矢量时,在液晶盒后依次放两种波片,目的是改变经过液晶盒后的光的偏振态,再置一偏振分光棱镜分开水平Ip和垂直Is线偏振分量,测得两组光强,根据公式算得该Stokes矢量,从而求解液晶盒盒厚以及扭曲角。实验中我们用该方法测量了不同盒厚、扭曲角度的TN液晶盒。实验结果证明该方法可行,结果准确,并且可以测量盒厚较小的液晶盒。最后,我们理论分析了实验误差。     

Numerical solution of higher order mode cut-off frequencies insymmetric TEM cells using finite element method [EMI measurementapplications]

The higher-order-mode cut-off frequencies in symmetric transverse electromagnetic cells are computed with the finite-element method. Transverse electric and transverse magnetic modes are considered. For symmetry, only one-quarter of the cross section is analyzed. Electric and magnetic walls are introduced in the cross section, which includes the effect of the gap between the center conductor and the sidewalls. This arrangement enhances the accuracy of the solution. The results obtained by this method are compared with those of other methods. Discrepancies observed in the results of other methods are explained. The present method is the more powerful one; with this method, mode identification can easily be made using an eigenvector solution     

原子层淀积技术应用于太阳电池的研究进展

原子层淀积(ALD)是一种先进的纳米级薄膜生长技术,在微电子和光电子领域有着广泛的应用前景,尤其在提高太阳电池的光电转换效率方面正发挥越来越大的作用,很可能成为下一代太阳电池工艺中的重要方法。文章综述了近年来ALD技术在太阳电池领域的应用研究进展,详细介绍了ALD技术应用在不同类型太阳电池的最新研究成果和存在的问题,并对其发展趋势进行了展望。     

Calculation of quantitative shunt values using photoluminescence imaging

A proof of concept study for a method of determining quantitative shunt values in silicon solar cells from photoluminescence images is presented. The method is based on interpretation of the luminescence intensity around a local shunt or recombination‐active defect in terms of the extracted current. The theoretical relationship between the photoluminescence signal and the shunt current is derived. Experimental results on specifically prepared test structures show good agreement with known shunt resistance values. Experimental data on diffused wafers are presented. The effect of the front metallisation in complete cells on the appearance and interpretation of shunts in photoluminescence images is investigated experimentally. The limitations of the method are discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

应用边界元法计算TEM小室中高次模的截止频率

本文提出了应用边界元法求解TEM小室中高次模截止频率的方法,求出了多个TE和TM模式的截止频率值。对于一对称小室,由于利用了电壁和磁壁,所以仅研究横截面的四分之一部分就可以得到满意的结果,并且很容易判断其模式。文中列出了一些计算结果并与其它方法的数据进行了比较。     

The Development of Evaluation Algorithm for Blood Infection Degree

In this paper, a series of processes are performed to assess the degree of infection in a subject’s blood infected with malaria. This process improves the existing testing method’s inefficiencies to assess the results obtained of the infected blood. Image processing algorithm was constructed to establish a standardized test procedure as a way to process the information. The algorithm is built to process the images obtained from the microscopic image of the infected blood and detect the extent of Plasmodium infection which is the cause of Malaria Disease. The images obtained from the infected red blood cells and uninfected red blood cells are processed using the image processing algorithm to distinguish the number of cells infected by malaria in the infected blood. A quantitative analysis is carried out using the results to evaluate the extent of the infection in the blood cells. To establish the relationship between the number of infected and uninfected cells, the algorithm was constructed based on color image processing through HSV color space and morphological image processing techniques. The key configuration for the proposed algorithm is the morphological image processing technique which clearly divide the red blood cells in the micrograph based on the extent of penetration of plasmodium in the blood cells using the clamp splitting method and categorize the infected blood cells.     

非晶硅肖特基太阳电池的I-V特性分析

本文提出了一种在光照和短路条件下测量Ni/-Si∶H肖特基结势垒宽度的方法。同时,又在实验确定的参数的基础上,从理论上计算了在AM1太阳光谱照射下Ni/-Si∶H太阳电池的I-V曲线。由此得到的非晶硅少子扩散长度的数值与作者1983年用表面光电压法(SPV)测得的是一致的。从计算结果出发,着重分析了影响填充因子的各种因素。与实验对比可以得出结论:被测太阳电池的填充因子小是串、并联电阻造成的,而不是扩散长度太短的缘故。     

复杂雷达体的二次电磁散射

讨论了用几何光学和物理光学方法计算两面元对上的二次电磁散射。建立了二次散射理论模型，并利用快速射线追踪搜索算法计算了典型形体及复杂目标的二次散射。计算表明该方法结果与理论值非常接近，而且处理计算速度非常快，在复杂目标可视化预估系统中可提高预估速度和可靠性。     

金纳米颗粒介导的细胞光穿孔表征方法

提出了一种新的表征方法--膜电位测量。膜电位恢复时间与膜穿孔尺寸相对应,因此建立起细胞膜穿孔尺寸的大小与激光能量阈值之间的关系,可为准确地向细胞内递送不同分子量的外源物质提供理论支持。将金纳米颗粒与胃癌细胞共同培养,在保证细胞不受金纳米颗粒毒性影响的前提下,选择不同能量纳秒脉冲激光照射共孵育后的胃癌细胞,并采用碘化丙啶(PI)和钙黄绿素乙酰甲酯(Calcein-AM)对穿孔后的细胞进行染色验证。结果发现:当加入直径为100 nm的金纳米颗粒,其数量与细胞数比为400\:1,激光能量密度在20 mJ/cm^2时,可以在保证细胞活性的前提下成功实现532 nm脉冲激光的细胞膜穿孔;在穿孔条件下,采用光标测技术测量细胞膜电位,发现细胞膜电位先增加后复原,最大增量为50 mV,恢复时间为250 s。膜电位结果再次验证,光穿孔造成的细胞膜损伤是可以恢复的,而且可以用膜电位变化来表征。     

Stimulation of Spheroidal Cells?The Role of Cell Shape

The behavior of spheroidal cells in an applied uniform field is examined in order to gain insight into the role of cell shape in the electrical activity of biological cells. The responses of cells having different eccentricities but the same height in the direction of stimulation are compared. The effect of a change in the direction of stimulation is discussed. In the process of obtaining the results an approximate method for calculating biopotentials during extracellular stimulation is presented and justified.     

一种逻辑内建自测试移相器的设计方法

针对内建自测试移相器，提出了一种基于逻辑仿真移相器设计和改进的快速算法。只需对几阶LFSR（Linear Feedback Shift Register）进行2^n-1个周期仿真即可得到合适的移相选择矢量，由这些选择矢量构成值胞。该方法得到的移相器选择矢量清晰地反映了值胞的组成和分布情况，从而避免了对偶LFSR的多次前向、后向仿真，降低了移相器的设计时间。对比实验表明，该方法是有效的，并且其硬件电路实现具有更小的硬件开销。     

基于光谱辐射度法的PDP显示屏色串扰评价

色串扰是 PDP 显示屏的一种特殊缺陷.本文先介绍了色串扰的起因,然后提出了一种新的基于光谱辐射度法的色串扰评价方法.该方法首先测量红、绿、蓝单色发光单元的光谱功率分布,然后在显示屏红场、绿场、蓝场下分别测量包含有足够象素(如 500 象素)显示区域的光谱功率分布,由此建立有关于串扰评价系数的关系式.选择单色发光单元测试结果中包含有足够强光谱功率的波段数据参与计算,计算得到上述串扰评价系数.本文分析了基于该方法的试验结果,并指出光谱辐射度法对于 PDP 显示屏而言是一种有效的色串扰评价方法.     

Modelling of bow-tie microstrip antennas using modified locallyconformal FDTD method

An analysis of bow-tie microstrip antennas is presented based on the use of the modified locally conformal finite-difference time-domain (FDTD) method. This approach enables the number of cells along the antenna length and width to be chosen independently of the antenna central width, which helps to keep the number of cells required in those directions to a minimum. The analysis results are compared with experimental results and good agreement is observed     

Nuclei Segmentation Using Marker-Controlled Watershed, Tracking Using Mean-Shift, and Kalman Filter in Time-Lapse Microscopy

It is important to observe and study cancer cells' cycle progression in order to better understand drug effects on cancer cells. Time-lapse microscopy imaging serves as an important method to measure the cycle progression of individual cells in a large population. Since manual analysis is unreasonably time consuming for the large volumes of time-lapse image data, automated image analysis is proposed. Existing approaches dealing with time-lapse image data are rather limited and often give inaccurate analysis results, especially in segmenting and tracking individual cells in a cell population. In this paper, we present a new approach to segment and track cell nuclei in time-lapse fluorescence image sequence. First, we propose a novel marker-controlled watershed based on mathematical morphology, which can effectively segment clustered cells with less oversegmentation. To further segment undersegmented cells or to merge oversegmented cells, context information among neighboring frames is employed, which is proved to be an effective strategy. Then, we design a tracking method based on modified mean shift algorithm, in which several kernels with adaptive scale, shape, and direction are designed. Finally, we combine mean-shift and Kalman filter to achieve a more robust cell nuclei tracking method than existing ones. Experimental results show that our method can obtain 98.8% segmentation accuracy, 97.4% cell division tracking accuracy, and 97.6% cell tracking accuracy     

一种高精度解析提取太阳电池参数的新方法

基于太阳电池光生电流远大于反向饱和电流、并 联电阻远大于串联电阻以及光生电流 近似等于负的短路电流3个边界条件,结合太阳电池在短路点、开路点和最大功率点处的极值 表述, 提出了一种解析求解太阳电池光生电流、反向饱和电流、理想因子、并联电阻和串联电阻5个电性参 数的方法,并研究了方法的特点。通过与文献实验数据的对比表明,本文方法不仅具有正确 性,而且 适用于各种条件下的各种类型电池;通过实验表明,本文方法具有较高的计算精 度和速度,误差在2%以下,时间小于0.2s。     

Higher order mode cutoff frequencies in TEM cells calculated withTLM method

The higher order mode cutoff frequencies in various symmetric TEM cells are calculated with the TLM method and some comments are made on comparisons between these results obtained by this method and other methods     

Fabrication of oxide heterostructures for promising solar cells of a new generation

The prospects of the fabrication of solar cells based on metal oxides (ZnO formed by the hydrothermal method) with a bulk heterojunction are considered. The results of synthesizing zinc-oxide nanorods on different seed layers are presented. The important role of seed-layer formation is noted. It is shown that the structure of nanorod arrays can be controlled using a surfactant. Faceted nanorods are obtained, which are promising for designing new-generation solar cells.