美国白蛾取食金叶榆及家榆对其生长发育的影响

以金叶榆、家榆为寄主植物,研究了不同寄主植物对美国白蛾生长发育和繁殖的影响。结果表明,美国白蛾比较喜欢取食家榆。美国白蛾1代幼虫取食金叶榆叶片的存活率为15.0%,取食家榆叶片的存活率为36.7%,第2代幼虫取食金叶榆叶片的存活率为82.7%,取食家榆叶片的存活率为84.3%;美国白蛾取食金叶榆叶片从初孵第2代幼虫到蛹...     

玻璃组成对CaO-Al2O3-SiO2系玻璃烧结、晶化和性能的影响

采用烧结法制备以钙长石为主晶相的微晶玻璃.采用差热分析(DTA)、X射线衍射(XRD)、扫描电镜(SEM)和性能测试研究玻璃组成对玻璃的烧结、晶化特性和性能的影响.结果表明:随着CaO含量的增加,玻璃转变温度和析晶放热峰温度逐渐降低,而且析晶放热峰变得尖锐;增加氧化钙降低玻璃的析晶活化能,有利于玻璃的析晶;随着SiO2量的增加,玻璃转变温度和析晶放热峰温度移向高温,使玻璃的析晶困难;玻璃样品的烧结温度随CaO含量的增加而降低, 但过多的CaO促进硅酸钙的析出,增加样品的介电常数和热膨胀系数;增加SiO2能够降低微晶玻璃样品的热膨胀系数,改善其介电性能;所制备的微晶玻璃具有相对密度高(≥98.3%),介电常数适中(6.9～7.5),介电损耗低(≤0.1%),热膨胀系数低(3.8×10-6～4.5×10-6 /℃),烧结温度(900～1 000 ℃)低,及介电常数温度稳定性低(66×10-6～113×10-6 /℃).     

fMRI time series analysis based on stationary wavelet and spectrum analysis

The low signal to noise ratio (SNR) of functional MRI (fMRI) prefers more sensitive data analysis methods. Based on stationary wavelet transform and spectrum analysis, a new method with high detective sensitivity was developed for analyzing fMRI time series, which does not require any prior assumption of the characteristics of noises. In the proposed method, every component of fMRI time series in the different time-frequency scales of stationary wavelet transform was discerned by the spectrum analysis, then the components from noises were removed using the stationary wavelet transform, finally the components of real brain activation were detected by cross-correlation analysis. The results obtained from both simulated and in vivo visual experiments illustrated that the proposed method has much higher sensitivity than the traditional cross-correlation method.     

简单网络时间协议分析及实现

介绍了信息技术对时间同步技术的需求,分析了简单网络时间同步的工作原理,讨论了时间同步的客户端软件实现.软件测试的结果表明同步精度可达1～50 ms.     

溅射时间对γ′-Fe4N薄膜的磁性影响

采用直流磁控溅射方法,以Ar/N2作为放电气体（N2/（Ar＋N2）=10%）,在玻璃衬底上于不同溅射时间获得了γ′-Fe4N单相薄膜。利用X射线衍射（XRD）和超导量子干涉仪（SQUID）研究了溅射时间对薄膜的生长及磁性性能的影响。结果表明薄膜样品明显沿γ′-Fe4N（111）晶面择优取向进行生长,其（111）晶面平行于样品的膜面。随溅射时间的增加,薄膜样品的晶粒尺寸没有明显的变化,薄膜厚度和矫顽力随溅射时间的增加而显著增大。     

蒙特卡洛法在油气储量估算中的应用

详细论述了蒙特卡洛法的数学原理及其在油气储量估算中的具体使用方法 ,并通过应用实例说明在油气田的不同勘探开发阶段 ,根据拥有资料的多少选用适当的数学模型 ,利用蒙特卡洛法都可以估算出一个具有一定可信度的比较合理的油气储量数值。当一个区块勘探程度较高 ,拥有资料较多时 ,用蒙特卡洛法估算的储量与用容积法估算的储量比较接近。     

黄刺莓和金针花粉营养成分的研究

通过对黄刺莓和金针花粉的DNA，RNA，磷脂，葡萄糖氧化酶，氨基酸，VA，VE和VC等重要营养成分的测定，发现这两种花粉的营养成分丰富，配比良好，特别是VA，VE，VC和必需氨基酸的质量比较高，RNA和DNA的质量比也较高。黄刺莓花粉和金针花粉具有很好的应用价值。     

Calmodulin modulation of ion channels and receptors

Ion channels and receptors are the structural basis for neural signaling and transmission. Recently, the function of ion channels and receptors has been demonstrated to be modulated by many intracellular and extracellular chemicals and signaling molecules. Increasing evidence indicates that the complexity and plasticity of the function of central nervous system is determined by the modulation of ion channels and receptors. Among various mechanisms, Ca 2+ signaling pathways play important roles in neuronal activity and some pathological changes. Ca 2+ influx through ion channels and receptors can modulate its further influx in a feedback way or modulate other ion channels and receptors. The common feature of the modulation is that Ca 2+ /calmodulin (CaM) is the universal mediator. CaM maintains the coordination among ion channels/receptors and intracellular Ca 2+ homeostasis by feedback modulation of ion channels/receptors activity. This review focuses on the modulating processes of ion channels and receptors mediated by CaM, and further elucidates the mechanisms of Ca 2+ signaling.     

动态载荷的频域识别方法

将动态载荷识别的频域方法归结为统一的形式 ,不论是随机激励还是确定性载荷 ,均可利用实测的系统响应及响应与激励间的广义传递矩阵进行动载荷的识别 .通过对识别过程中精度影响因素的分析 ,提出利用计算机模拟方法选择响应测点以提高识别精度的方法 ,有利于工程应用 .     

单层椭圆抛物面网壳在地震作用下的动力稳定性分析

以平面30 m×30 m,矢跨比分别为1/6,1/7,1/8和1/9的椭圆抛物面单层网壳为对象,利用ANSYS非线性动力软件,研究其弹塑性动力失稳。计算中考虑几何和材料非线性效应,并对几何缺陷、阻尼、不同地震波及其输入方向等对稳定性的影响进行了分析。结果表明:该结构的动力失稳一般伴随着较大的塑性变形,具有明显的突发性;在水平地震作用下动力稳定临界荷载明显低于竖向地震作用下的临界荷载,以两向地震作用下最低;在水平地震作用下,较大矢跨比时动力稳定临界荷载较低;杆件截面的增大可显著提高该结构的水平刚度和动力稳定临界荷载;几何缺陷能显著降低网壳结构的动力稳定临界荷载;考虑Raleigh阻尼模式,其临界荷载提高不足7%。