Biochemical characterization of the protein encoded by rice osRACD gene

A recombinant plasmid pET-racd was first constructed by cloning osRACD,the development-regulating gene that controls photoperiod fertility transformation in the photoperiod sensitive genic male sterile rice Nongken 58S,into a prokaryote expression vector pET28a(+).It was then transformed into E.Coli BL-21.Cutting with thrombin of the fusion protein extracted from transformants and PAGE separation yielded pure osRACD protein,which was further concentrated using ultrafiltration and renatured using glutathione oxidation/reduction refolding system for later functional study.As demonstrated by in vitro functional assay,the osRACD protein expressed in E.Coli B-21 shows remarkable activity in binding GTP specifically and hydrolyzing it.     

基于相关矩阵对角化和遗传算法的盲源分离法

提出了一种新的基于相关矩阵对角化的代价函数作为衡量输出信号独立性的测度。为了扩大搜索空间,降低各信源之间的互相关性,将代价函数进行了非线性变换。还提出了利用实数编码的遗传算法对代价函数进行最优化搜索,以克服传统梯度搜索方法容易陷入局部收敛的缺点。此方法不仅适用于平稳或非平稳信号,而且还可用于瞬时或卷积混和模型的盲源分离问题。仿真实验表明,该算法具有快速收敛性能和高精确度等优点,能够大大提高分离后的输出信噪比。     

Kriging插值与拉丁超立方试验相结合构造电路元模型

电路系统的设计与优化常常需要参数与指标问简单、直接的模型，即电路的元模型。本文将Kriging插值和拉丁超立方抽样试验相结合构造了低功耗集成运算放大器的元模型。对于这种输出结果为确定值的电路仿真试验，与基于传统部分要因试验设计的多项式回归模型相比，Kriging模型具有更高的预测能力。     

基于DSP-MCU数字化焊接电源系统的设计

采用TMS320F240数字信号处理器和80C196KC单片机设计多功能IGBT逆变焊接电源双机控制系统.其中,TMS320F240主要用于焊接参数的采样、控制算法的运算;80C196KC用于完成人机接口的功能,包括键盘和显示,与上位机的通信等.设计中人机界面采用液晶显示.系统设计的关键是双机之间的通信技术,为了确保通信的可靠及快速性采用双口RAMIDT7005来完成.数字PWM控制单元采用复杂可编程逻辑器件(CPLD)完成,整个系统中所有逻辑控制也由此芯片来完成,实现了多功能焊机的全数字化控制.     

数字图像处理技术在指针式仪表读数系统中的应用

阐述了基于图像处理技术的指针式仪表自动读数系统的结构和工作原理，分析了采用Matrox MeteorⅡ图像采集卡应用软件系统的开发特点．在图像处理方法上，比较了Canny算法和Morlet小波基函数的小波变换算法对图像边缘检测的效果．结果表明，采用小波变换检测边缘，提高了检测精度，满足了实际应用的需求．     

Development of the CAS-IBB single-particle microbeam for localized irradiation of living cells

A single-particle microbeam facility has been constructed at the Key Laboratory of Ion Beam Bioengineering (LIBB), Chinese Academy of Sciences (CAS). The system was designed to deliver a defined numbers of hydrogen ions, produced by a van de Graaff accelerator, in an energy range of 2.0-3.0 MeV, into an area smaller than that of the nucleus of an individual living cell. The beam is collimated by a borosilicate glass capillary that forms the beam-line exit. An integrated computer program recognizes the cells and locates them one by one over the microbeam exit for irradiation. We present technical details of the CAS-LIBB microbeam facility, particularly on the collimator, hardware, control program, as well as cell irradiation protocols available. Various factors contributing to the targeting and positioning precision are discussed along with accuracy measurement results.     

Numerical tests of efficiency of the retrospective time integration scheme in the self-memory model

A set of numerical tests was carried out to compare the retrospective time integral scheme in a self-memory model,whose dynamic kernel is the barotropical quasi-geostrophic model, with the ordinary centered difference scheme in the barotropical quasigeostrophic model. The Rossby-Haurwitz wave function was taken as the initial fields for both schemes. The results show that in comparison with the ordinary centered difference scheme, the retrospective time integral scheme reduces by 2 orders of magnitude the forecast error, and the forecast error increases very little with lengthening of the time-step. Therefore, the retrospective time integral scheme has advantages of improving the forecast accuracy, extending the predictable duration and reducing the computation amount.     

CCI土壤湿度产品在中国区的降尺度与融合研究

以欧洲航天局主/被动微波遥感融合的土壤湿度产品数据为主要数据源,结合地表参数、亮度温度、土壤质地、地形、降雨等辅助数据,提出基于移动窗口的线性、非线性联合的土壤湿度降尺度模型,对中国区域2003年1—12月的CCI土壤湿度产品数据进行降尺度,提高CCI土壤湿度数据的空间分辨率,使其更适用于农业、水文模拟等精细尺度的应用要求。为了克服CCI数据冬季缺失较多的情况,利用第3代再分析资料ERA-Interim表层土壤湿度的降尺度和重采样结果与之进行融合,生成空间覆盖完整的2003—2013年中国区月1 km土壤湿度数据集,并利用站点实测数据集对其进行了验证。结果表明,依据主/被动微波融合CCI、ERA-Interim再分析土壤湿度数据以及辅助数据的基于移动窗口和线性非线性集成的中国区地表土壤湿度降尺度和融合方法,提高了CCI土壤湿度数据集的空间分辨率和空间覆盖,同时还一定程度上提高了土壤湿度的估算精度。     

不同频率超声波对养殖水体浮游植物群落结构的影响

采用单因子梯度试验法,设定20（I）、28（II）和40kHz（III）3个不同低频率超声波试验组,以不进行超声波作用为对照组,研究超声波对养殖水体中浮游植物群落结构的影响. 40d的试验结果表明：对照组浮游植物的丰度为各组最高,试验组II、III中,浮游植物丰度分别为3.8×10⁵、2.3×10⁵ ind·L^-1,显著低于对照组（P<0.05）. 共鉴定到浮游植物种类属数为16个,数目大小依次为试验组I>试验组II>试验组III>对照组. 试验组I中Shannon wiener多样性指数（H）、Margalef丰富度指数（D）分别达1.661±0.055和1.071±0.020,为各组最高;试验组III中Pielou均匀度指数（J）达0.619±0.018,为各组最高;与对照组相比,施加20kHz超声波显著提高了养殖水体中浮游植物生物群落多样性（P<0.05）.     

基于抽象语法树的C克隆代码重构应用与研究

为了缩短软件工程生命周期,引入组件、复制的概念,利用抽象语法树(AST)将相同功能的代码设计为一个函数,保留充足的接口参数,利用过程调用开发软件程序,可以提高软件开发效率.