阵列系统中多端口网络噪声系数测试分析

多端口网络常用于阵列系统中进行波束合成,其噪声系数测试成为系统设计的关键问题。给出了多端口网络模型,基于将多端口网络转化换成双端口网络的思想,给出了3种测试方法。方法一和方法二将多端口网络n-1个输入端口接负载,只留一个端口作为输入,其区别是加电工作的有源双端口网络数量不同。方法三在多端口网络前接一n分路器。通过对网络信号功率和噪声功率进行详细的分析和推导,给出了不同情况下的噪声系数。通过试验验证了测试方法的正确性。     

面向掩模精化的表面微加工MEMS器件几何建模

MEMS器件设计流程中,为优化MEMS器件,常常需要对MEMS掩模进行精化设计.为了在MEMS精化设计中同步更新MEMS掩模与几何模型,提出一种面向掩模精化的表面微加工MEMS器件几何建模方法.该方法主要通过建立MEMS器件几何模型和工艺模型之间的依赖关系图,通过变动依赖关系,求出掩模精化所影响的几何元素,而后在几何模型中仅仅更新所影响的几何元素;对于所对应的几何模型存在拓扑突变等情况,该方法采用参数限定或局部几何模拟进行更新.实例分析表明,提出的几何建模方法能快速有效地响应掩模精化,从而有效地促进MEMS器件设计.     

用于硅片传输系统的机械手设计

介绍了用于硅片传输系统的机械手发展现状,主要针对300 mm全自动探针测试台的工艺需要进行机械手系统设计,对机械手结构以及设计中需要注意的关键技术进行了阐述。该设计可以推广到整个半导体生产线中其他工艺设备的应用,对未来大尺寸半导体生产线的国产化具有很大意义。     

改进的16进制正交幅度调制码的相位估计算法

相干光通信系统中的相位恢复是克服信号收发端和传输过程中产生的相位噪声的必要步骤。为获得低的运算复杂度和良好的相位估计效果,本文对传统的四次方相位估计算法进行了改进,使之具有自适应的数据块长度控制功能。通过理论分析以及Matlab数值仿真方法验证改进的效果。对于16进制正交幅度调制码（16QAM）,改进后的算法在几乎不增...     

Synthesis,Characterization and Crystal Structure of One Ni_2（salen）_2 Complex

A homochiral complex,Ni 2 (salen) 2 (1,salen=(R,R)-(-)-N,N-bis(3-tert-butyl-5-(4ethynylpyridyl)salicyl-idene)-1,2-diaminocyclohexane),has been synthesized and characterized by IR,microanalysis,CD spectra,TGA,powder and single-crystal X-ray crystallography.It crystallizes in triclinic,space group P1 with a=11.896(2),b=12.571(3),c=13.197(3),α=65.61(3),β=73.90(3),γ=75.87(3)o,V=1707.9(6) 3,Z=2,C 42 H 42 N 4 NiO 2,M r=693.51,D c=1.349 g/cm 3,F(000)=732,μ=0.612 mm-1,GOOF=1.015,the final R=0.0290 and wR=0.0796 for 9002 observed reflections with I > 2σ(Ⅰ).The complex architecture is constructed by intermolecular π···π interaction and assembled into a 2D structure via C-H···π interactions between the cyclohexanes and pyridine rings.     

表柔比星-镁体系与DNA相互作用初步研究

表柔比星是临床上用于治疗快速增殖肿瘤的药物。本文应用紫外、荧光、圆二色、黏度、凝胶电泳等方法研究了表柔比星-Mg2+体系与DNA的作用。结果发现:在pH=7.4时,表柔比星可与Mg2+形成稳定体系。加入DNA后表柔比星-Mg2+体系的紫外吸收明显降低;Scatchard图表明表柔比星-Mg2+体系对溴化乙锭(EB)与DNA的结合为竞争性抑制;同时此体系可使DNA-EB体系荧光偏振度增大;使DNA的热变性温度(Tm)上升;黏度增大;凝胶电泳表明表柔比星-Mg2+体系对pBR322DNA有非常好的切割活性;圆二色谱法表明随着表柔比星-Mg2+体系的加入,DNA碱基间作用能迅速减弱,二级结构发生了显著的变化。综上所述:表柔比星-Mg2+体系与DNA之间为嵌插作用;且表柔比星-Mg2+体系具有更好的切割活性。这些结果,可为合理改善药效和设计新药提供依据。     

Quantification of changes in oxygen release from red blood cells as a function of age based on magnetic susceptibility measurements

This study extends the in vitro understanding of the RBC storage lesion by serially analyzing the RBC's magneophoretic mobility, a property dependent on the content and oxygenation or oxidation state of hemoglobin (Hb) iron, during storage. Four prestorage leukoreduced, AS-5 preserved RBC units were stored between 1 and 6 °C for 42 days. Weekly starting on storage day 7, each unit was sampled, divided into 3 aliquots, each subjected to different reactions: one aliquot was exposed to room air to produce oxyhemoglobin (oxyHb), another aliquot was mixed with sodium nitrite to produce methemoglobin (metHb), while the third aliquot was desaturated of oxygen (deoxyhemoglobin, deoxyHb) using nitrogen gas. These aliquots were placed into a cell tracking velocimetry (CTV) apparatus which measured both the settling velocity (u(s)) of the RBCs as well as their magnetically induced velocity (u(m)). The u(m)/u(s) ratio depends on the oxygenation state of the hemoglobin and the quantity of iron within the RBC. The RBC density was measured by percoll centrifugation. There was a significant reduction in the u(m)/u(s) ratio for the deoxyHb RBC aliquot as storage time elapsed, with a smaller but still significant reduction in the u(m)/u(s) ratio for the metHb aliquot. The average RBC density decreased very slightly during storage, as determined by the percoll centrifugation technique, although the average settling velocity (another measure of cell density) seemed to fluctuate during storage. The decrease in magnetophoretic mobility of the deoxyHb portion is explicable either by Hb's increased affinity for oxygen during storage, or else a loss of iron from the cells.     

Detection of proteins on silica-silver core-shell substrates by surface-enhanced Raman spectroscopy

We have employed the proposed Silica-Silver Core-Shell (SSCS) SERS-active substrates to detect four model proteins: lysozyme (a protein without chromophore), cytochrome c (a protein with chromophore of heme), fluorescein isothiocyanate (FITC)-anti human IgG (labeled with FITC) and atto610-biotin/avidin (recognition with labeled small molecules). SERS spectra of these proteins and Raman labels on the SSCS substrates show both high sensitivity and reproducibility, which are due to electromagnetic SERS enhancement with additional localization field within closely packed Ag nanoparticles decorated on the SiO(2) nanoparticles and the aggregation of SiO(2)@Ag particles. We have found that the SERS intensities of atto610-biotin/avidin adsorbed on the SSCS substrates are about 20 times stronger than those from Ag plating on Au-decorated substrate. Moreover, the broad surface plasmon resonance (SPR) of the proposed substrates will extend SERS applications to more biological molecules with different laser excitations.     

一种改进的梳状拦阻式干扰

针对传统的梳状拦阻式干扰存在干扰机干扰功率一定时,用于干扰非固定信道目标通信信号的有效干扰功率较低这一问题,提出了一种改进的梳状拦阻式干扰方法。在研究梳状拦阻式干扰原理的基础上,通过调整各频段干扰信号的相关参数,使之与对应频段上相应目标通信信号相匹配,达到在相同条件下提高干扰效果的目的。仿真实验验证了改进后的这种干扰方式的有效性和优越性。