硅氧烷改性环氧丙烯酸酯及其紫外-湿气双固化涂层的性能

以环氧树脂和丙烯酸合成环氧丙烯酸酯,再与正硅酸乙酯反应,合成硅氧烷改性的环氧丙烯酸酯。以FT-IR分析合成产物的结构和UV-湿气固化过程;研究UV-湿气双重固化硅氧烷改性环氧丙烯酸酯涂膜的性能。以正硅酸乙酯封闭环氧丙烯酸酯的羟基,使环氧丙烯酸酯的黏度降低82%;经紫外-湿气双重固化,改性环氧丙烯酸酯涂层的摆杆硬度、耐磨性、水接触角均比未改性样品大幅提升,起始热失质量温度比未改性环氧丙烯酸酯高约63℃。     

Quantitative Determination and Confirmation of Five Synthetic Glucocorticoid Residues in Milk Powder by Gel Permeation Chromatography–Liquid Chromatography–Tandem Mass Spectrometry

A new method for multi-residue determination of five synthetic glucocorticoids (betamethasone, dexamethasone, prednisone, prednisolone, and hydrocortisone) in milk powder is developed. The glucocorticoids in the samples were extracted with tert-butyl methyl ether under ultrasonication incubation, and then cleaned up through gel permeation chromatography. After C18 LC gradient elution separation using acetonitrile with 0.1% formic acid as a mobile phase, the eluents were determined by liquid chromatography–tandem mass spectrometry with multiple reaction monitoring and positive ionization modes. The effective separation for the five glucocorticoids was achieved. The limit of quantification of the method for testing five glucocorticoids in milk powder was in the range from 0.2 to 0.5 μg kg⁻¹, which was lower than the maximum residue limits established by European Union for glucocorticoids in foods. Experiments on spiked samples of milk powder showed that the mean recoveries at addition level of 1.0, 3.0, and 5.0 μg kg⁻¹ were in the range of 71.2% and 103%, and the relative standard deviation ranged from 4.7% to 16.8%. The calibration curves for these drugs between 1.0 and 100 μg l⁻¹ showed good linearity, with correlation coefficient (r) more than 0.999. The real sample test showed that this method is sensitive and accurate. It can be used for qualitative and quantitative determination of studied glucocorticoid residues in milk powder samples.     

基于MATLAB的双正态总体均值线性关系假设检验问题的探讨

本文主要基于MATLAB的基础之上,采用检验P值,针对方差为已知情况下讨论双正态总体均值线性关系的假设检验问题.     

一种高斯尺度混合模型的Shearlet域图像去噪(英文)

提出了一种基于高斯尺度混合模型的Shearlet域图像去噪方法.高斯尺度混合是一个独立高斯随机向量和一个独立隐随机尺度因子的乘积,可以很好地刻画相邻位置和尺度的Shearlet系数邻域的统计特性.在此基础上,对Shearlet系数进行贝叶斯最小均方估计.通过对加入高斯白噪声的图像进行去噪,仿真结果表明和其他基于小波域的方法相比,无论从视觉上还是峰值信噪比上,shearlet域方法降噪效果明显更好.     

Study on the optimal hydropower generation of Zhelin reservoir

Zhelin reservoir, a multi-purpose reservoir designed mainly for hydropower generation, is located in Xiushui watershed in Jiangxi Province, China. As the rainfall has a decreasing trend in recent years, the reservoir storage capacity cannot be fully filled and the original operation rule can no longer fulfill the desired target for power production. In order to ensure the dam safety and produce more economic benefits from hydropower generation, the original operation rule of the reservoir needs to be evaluated for possible improvement to yield optimal benefits. In this study three optimization algorithms including progressive optimization algorithm (POA), particle swarm optimization (PSO) and genetic algorithm (GA) are applied. According to a long discharge data series, the minimization of water consumption rate is chosen as the objective function, along with several physical and operational constraints. After comparing the results of the three methods, POA is found more suitable for Zhelin reservoir. Sensitivity of the optimization algorithms is also analyzed, of which, the step size of water level of the reservoir for POA, the initial population sizes for PSO and GA are also explored to search for the most suitable parameters. The investigation further reveals that step size 0.01 m, population size 50 and 30 are the best choice for POA, PSO and GA, respectively.     

H68合金退火料温对其晶粒度的影响

本文对深冲用H68合金成品退火的晶粒度之影响因素进行分析,通过对原始晶粒度冷轧后（ε〉50%）的各种不同料温的晶粒度测试试验作出了不同料温情况下晶粒度的关系图,最后得出了两点结论,第一,H68合金板带的成品退火晶粒度不受原始晶粒度的影响,退火前冷加工率超过50%成品软态的晶粒度可获得最佳值;第二,H68合金板带的晶粒度与退火料温的关系是在550℃以下呈线性变化,大于550℃后变化不明显。     

Optimization analysis using orthogonal array designs for magnet girder assembly of SSRF

An optimization analysis for finite element (FE) results by variance analysis method (VAM) of orthogonal array designs (OADs) was performed to improve the dynamic performance of the prototype magnet girder assembly (MGA) in the storage ring of the Shanghai Synchrotron Radiation Facility (SSRF).Seven factors were considered.The analyses show that the most important factor for the first eigenfrequency is stiffness of the support systems,and the main factor resulting in the relatively low first eigenfrequency of the MGA is its weak support systems.From the OADs optimization analysis,mechanical design of the MGA was improved,and its dynamic performance was improved obviously.     

人行过街横道通行能力的研究与应用

本文应用交通流理论,分析了过街人流受机动车和非机动车流干扰的累计延误,给出了在一定车流强度条件下,人行过衔横道通行能力的计算模型,从而为确定人行立交工程建设的适宜交通流量提供了定量分析的方法。文中演示了两个典型算例     

基于动力学环境试验数据的模态参数识别

在被测系统做动力学环境试验的同时，将振动台台面和被测系统组成的新系统作为分析对象，以振动台给定的力谱（或加速度谱）作为激励，对被测系统进行模态参数的识别。基于结构的振动台环境试验数据，通过被测系统频域中的测点加速度测量值与台面加速度测量值之间的传递率函数，导出了一个被测系统的“广义频率响应函数”，并且通过对边界条件的进一步简化和假设，最终得到了系统的模态参数。仿真算例验证了本方法的有效性。     

CDMA系统中寻呼信道的负荷及优化分析

寻呼信道不仅能够传送系统的寻呼消息,而且还能够传输系统消息并进行鉴权登记等,因此寻呼信道的性能对整个网络性能指标的提高起了极其重要的作用。文中针对寻呼信道中通用寻呼消息,开销消息,短消息等随着话务量的变化对寻呼信道容量产生的影响做出了分析,并进一步提出了优化意见。