pH响应性聚乙二醇-co-聚丙烯酸交联微球的合成

在N,N′-亚甲基二丙烯酰胺(Bis)存在的条件下,以偶氮二异丁腈(AIBN)为引发剂,使苯乙烯单封端聚乙二醇(St-PEG)大分子单体与丙烯酸(AAc)在3-戊酮溶液中进行分散共聚反应,得到了聚乙二醇-co-聚丙烯酸(PEG-co-PAAc)交联微球.动态激光光散射测试结果表明,所得的交联微球具有良好的单分散性;同时发现,在共聚反应中St-PEG大分子单体、AAc和Bis溶液浓度对交联微球粒径有明显的影响;交联微球的Rh在pH为4.5附近突然增加,并在pH>7.0后保持不变,说明该PEG-co-PAAc交联微球具有明显的pH响应性.     

Analyzing Nonstationary Random Response of a SDOF System under the Evolutionary Random Excitation by Wavelet Transform

For evolutionary random excitations, a general method of analyzing nonstationary random responses of systems was presented in this paper. Firstly, for the evolutionary random excitation model, the evolutionary power spectrum density function （EPSD） of a random excitation was given by wavelet transform. Based on the EPSD, the nonstationary responses of a SDOF system subjected to evolutionary random excitations were studied. The application and validity of presented method were illustrated by numerical examples. In numerical examples, the recently developed stochastic models for El Centro （1934） and Mexico City （1985） earthquakes which preserve the nonstationary evolutions of amplitude and frequency content of ground accelerations were used as excitations. The nonstationary random mean-square responses of a SDOF system under these two excitations were evaluated and compared with simulated results.     

高分辨率自然伽马测井仪器研制方案设计

在国内外文献调研的基础上,针对传统的自然伽马测井仪器的特点,提出了自然伽马测井仪器实现高分辨率的技术关键,并据此进行了高分辨率自然伽马测井仪器研制的初步方案设计,按照本方案研制出的自然伽马测井仪器的纵向分辨率将由传统的0.6米提高到0.4米,曲线重复误差为7%.研制的实际开展表明该方案是科学、合理的,对其他类似研究具有很强的参考价值.     

智能型水凝胶改性研究进展

智能型水凝胶是一类具有广泛应用前景的功能高分子材料,但由于传统水凝胶存在一些缺点因而限制了其应用,因此近年来围绕提高传统水凝胶的性能做了大量研究工作.该文从4个主要方面综述了近年来智能型水凝胶改性的研究进展.     

Synthesis and photocurrent response of porphyrin-containing conjugated polymers

In recent years conjugated polymers have attracted considerable attention because of their potential appli- cations in the fields of light emitting diodes, photo- voltaic devices, and sensors[1―7]. In the fabrication of semiconductor photovoltaic devices…     

Climate change and hydrologic process response in the Tarim River Basin over the past 50 years

Climate change and hydrologic process response in the Tarim River Basin over the past 50 years are the focus of more and more researchers＇ attention. In this paper, both temperature and precipitation time series were found to present a monotonic increasing trend using nonparametric tests. Noticeably, a significant step change in both temperature and precipitation time series occurred in 1986. By contrasting the trends of natural water process in headstream and mainstream, we found that it was anthropogenic activities not climate change that caused the river dried up and vegetation degenerated in the lower reaches of Tarim River. The results of gray correlation analysis show that the runoff of higher latitude distributing river is more closely associated with winter snow stocking, while that of lower latitude is more closely related to summer temperature. Runoff in the headstream is more sensitive to precipitation, while that in the mainstream is more sensitive to evaporation. The strong evaporation caused by increasing temperature weakened runoff to some extent in spite of the fact that precipitation increased over the past 50 years.     

用于信息安全的光学技术与数字技术

信息安全性牵涉的范围很广，从国防到我们的实际生活各个方面。本书的内容可以应用于安全、验证、识别、跟踪、鉴定。涉及光学科学与工程、数字图像处理、成像技术、基于计算机的信息系统、传感器、检测器和生物测量中各种不同的专门知识，本书的作者是这个领域的国际上公认的杰出人士，书中汇集了该领域最近的关键性突破。     

磁共振弥散加权成像(DWI)在急性脑缺血中的诊断价值

目的：探讨磁共振弥散加权成像（DWI）在急性脑缺血中的诊断价值．方法：对50例急性脑缺血患者的常规的MRI、液体衰减翻转恢复（Flair）和DWI图像进行比较研究分析．结果：50例患者经DWI扫描，均可发现梗塞灶，病灶检出率为100％，而15例发病在6h以内的超急性脑梗塞患者中，常规MR扫描T2WI上只有1例有轻微改变，而DWI均可显影；在35例发病在6～24h以内的急性脑梗塞患者中，T2WI上可逐渐显示病灶，但DWI显影更为清晰，显示病灶的范围也大于T2WI上的病灶．结论：DWI对诊断急性脑缺血十分敏感，能对急性脑缺血做出明确诊断．     

杭州照相机械研究所进军LED产业

杭州照相机械研究所长期以来从事各种光学系统和非球面光学塑料透镜的研究开发，取得了一系列的成果。主要研究领域为成像光学系统（如各类投影镜头、数码相机镜头、监控摄像镜头）和光通讯光学系统（如激光大气通讯光学系统、准直透镜、传感透镜、扫描镜头等），特别在光学塑料透镜的研发上取得了很好的成效。目前该所已建立大批量生产光学塑料透镜的质量管理保证体系，年产各类光学塑料透镜2000余万片。     

分辨率达1纳米的金属透镜

突破光学显微镜限制的成像技术，一提到“透镜”，大家立刻会想到放大镜、隐形眼镜等用透明物质做成的东西。但是，本文所讨论的透镜，却是用金属制造的，而且这种金属透镜的分辨能力，远远超过了光学显微镜。采用金属透镜，可以研制出前所未有的新型显微镜，还能够用于制造超精细的半导体集成电路芯片等，因此，金属透镜是划时代的研究成果。[编者按]