Camina-Gagen定理的一个推广(Ⅳ)

设G是2-(v,k,1)设计D的全自同构群Aut(D)的一个子群,且G是区本原的.若k2=k/(k,v)=17或18,则G也是点本原的.     

渐降低温胁迫对黄瓜幼苗叶绿体膜相关指标的影响

为了进一步说明模拟自然界温度渐降低温胁迫的冷害作用的机理,以黄瓜品种“津优1号”为试材,以直降低温胁迫（昼温/夜温=（10±0.5）℃/（5±0.5）℃）为对照CK,常温（昼温/夜温=（25±0.5）℃/（18±0.5）℃）为对照CK₁,研究渐降低温胁迫（即以1 ℃·h^-1的平均降温速度进行降温处理）对黄瓜幼苗叶绿体膜相关指标的影响.结果表明：（1）Ca²⁺ATPase和Mg²⁺ ATPase活性在低温胁迫过程中呈先上升后下降趋势,随着低温胁迫的进程,渐降低温胁迫下2种酶活性下降的幅度明显低于直降低温胁迫.（2）经过低温胁迫,冷害指数、叶绿体膜蛋白质量浓度和叶绿素质量浓度显著下降.（3）处理T的冷害指数、膜蛋白和叶绿素质量浓度、Ca²⁺ ATPase和Mg²⁺ ATPase活性均显著高于CK.总之,渐降低温胁迫可以减少叶绿体膜的损伤,增强抵御低温逆境胁迫的能力.     

An interconnecting bus power optimization method combining interconnect wire spacing with wire ordering

On-chip interconnect buses consume tens of percents of dynamic power in a nanometer scale integrated circuit and they will consume more power with the rapid scaling down of technology size and continuously rising clock frequency, therefore it is meaningful to lower the interconnecting bus power in design. In this paper, a simple yet accurate interconnect parasitic capacitance model is presented first and then, based on this model, a novel interconnecting bus optimization method is proposed. Wire spacing is a process for spacing wires for minimum dynamic power, while wire ordering is a process that searches for wire orders that maximally enhance it. The method, i.e., combining wire spacing with wire ordering, focuses on bus dynamic power optimization with a consideration of bus performance requirements. The optimization method is verified based on various nanometer technology parameters, showing that with 50% slack of routing space, 25.71% and 32.65% of power can be saved on average by the proposed optimization method for a global bus and an intermediate bus, respectively, under a 65-nm technology node, compared with 21.78% and 27.68% of power saved on average by uniform spacing technology. The proposed method is especially suitable for computer-aided design of nanometer scale on-chip buses.     

A new metric for rotating black holes in Gauss-Bonnet gravity

This paper presents a new metric and studies slowly rotating Gauss-Bonnet black holes with a nonvanishing angular momentum in five dimensional anti-de Sitter spaces.Taking the angular momentum parameter a up to second order,the slowly rotating black hole solutions are obtained by working directly in the action.In addition,it also finds that this method is applicable in higher order Lovelock gravity.     

Controlled phase gates based on two nonidentical quantum dots trapped in separate cavities

We propose a scheme for realizing two-qubit controlled phase gates on two nonidentical quantum dots trapped in separate cavities. In our scheme, each dot simultaneously interacts with one highly detuned cavity mode and two strong driven classical fields. During the gate operation, the quantum dots undergo no transition, while the system can acquire different phases conditional on different states of the quantum dots. With the application of the single-qubit operations, two-qubit controlled phase gates can be realized.     

基于Harris角点检测的位移测量算法

在力学实验中,位移和应变的测量是最基本任务之一。本文提出了一种基于Harris角点检测的位移测量算法。通过检测变形前图像的角点,然后利用光流跟踪技术在变形图像中搜索其匹配点,最终计算得到位移值。算法对图像采用网格划分方式进行计算,达到了全场测量的目的。实验结果表明,该算法位移测量精度高、稳定性好,可作为基于图像处理的无损测量方法。     

固液界面光催化裂解水的理论进展

二氧化钛纳米颗粒作为一种光催化剂,目前已经得到了广泛的应用,但是对于光催化反应的理解,尤其是在原子水平上,还明显不足,如TiO₂纳米颗粒的几何结构与光催化反应活性的构效关系。本文主要介绍了我们课题组在TiO₂裂解水的一些理论研究进展。通过周期性密度泛函以及周期性连续介质模型的理论计算,我们研究了水析氧反应(OER)的机理,得出了反应的决速步骤是失去第一个质子的过程,同时研究了不同纳米颗粒对该决速步骤的影响。研究指出,TiO₂纳米颗粒的热力学平衡构型在1-30nm内会受到其颗粒尺寸的显著影响;尖的TiO₂纳米颗粒比扁的颗粒具有更高的OER反应活性。综合以上两个因素,最终导致了光催化反应的形态依赖性。     

Electromagnetic absorption properties of flowerlike cobalt composites at microwave frequencies

In this work,we report the electromagnetic absorption(EMA) properties of composites consisting of micrometersized cobalt with flowerlike architecture synthesized by a facile hydrothermal reduction method.Compared with the conventional spherical Co-paraffin composites,the flowerlike Co-paraffin composites are favorable with respect to EMA performance in the low frequency region,ascribing interfacial polarization loss and Ohmic loss to the improvement in the impedance match.     

温室黄瓜病虫害的叶绿素荧光光谱分析

基于叶绿素荧光光谱分析技术,从光谱形态角度出发确定了波长685 nm作为健康与病虫害叶片分析的第一特征点,采用简单波段自相关选择与主成分分析方法相结合实现对光谱的降维处理,并在保持光谱信息达到99.999%的前提下将主成分因子个数由10降为5。对比分析了偏最小二乘回归、BP神经网络和最小二乘支持向量机回归三种建模方法,以真实值与模型预测值的相关系数作为评价标准,最终确定最小二乘支持向量机为温室黄瓜病虫害叶绿素荧光光谱分析的一种较为适宜的建模方法。     

温室黄瓜蚜虫害的荧光光谱监测与预警

利用叶绿素荧光光谱分析技术研究温室黄瓜蚜虫害的侵染及发生等级。从光谱形态的角度建立监测特征点,确定F632波段强度值作为健康与蚜虫害叶片的第一特征点,F512～F632光谱曲线的变化速率K值作为第二特征点,对于符合特征点的植株进行及早预警。采用最小二乘支持向量机数据挖掘方法的径向基核函数建立蚜虫害的侵染及发生等级模型,通过对比不同峰谷值所在波段对于蚜虫害的分类准确率和预测准确率,确定采用F632波段建立模型,它的预测能力达到96.34%。