SiC-WC复相陶瓷的力学性能与显微结构

在α-SiC和β-SiC超细粉末中,以Al、B、C为烧结助剂,分别添加0～24vol%WC,研究了SiC—WC复相陶瓷的力学性能和显微结构,获得了一种室温弯曲强度和断裂韧性分别达700MPa和8.6MPa·m(1/2)的SiC-WC复相陶瓷.     

具有奇数m阶循环子群的8m阶群的完全分类

本文给出了具有奇数m阶循环子群的8m阶有限群的完全分类。     

星核反应密度涨落运动方程

依据非平衡统计理论和动力学理论、采用生成泛函方法导出了描述恒星内部核反应密度涨落的广义Master方程,并对该方程的性质及适用范围做了分析。     

模态分析的应力方法

基于弹性体固有振动问题的余能变分原理,导出了弹性体固有振动的应力模态方程,进而探讨了一种模态分析的应力方法。并以平面桁架和简支矩形板为例说明了以应力作为基本变量的模态分析方法的可行性。     

Characterization of viscoelastic properties of hydrolyzed polyacrylamide using the stress recovery experiment

Polymer solutions have very important applications in the enhanced oil recovery due to their unique viscoelastic properties increasing microscale displacement efficiency. In this paper, the viscoelastic properties of partially hydrolyzed polyacrylamide (HPAM) solution have been investigated. Results show that the viscoelastic properties of HPAM increase with HPAM concentration increasing, and decrease with the increase of sodium dodecyl sulfate (SDS).Meanwhile, adding NaCI can destroy the viscoelastic properties.     

A simple rectification method for linear multi-baseline stereovision system

The linear multi-baseline stereo system introduced by the CMU-RI group has been proven to be a very effective and robust stereovision system. However, most traditional stereo rectification algorithms are all designed for binocular stereovision system, and so, cannot be applied to a linear multi-baseline system. This paper presents a simple and intuitional method that can simultaneously rectify all the cameras in a linear multi-baseline system. Instead of using the general 8-parameter homography transform, a two-step virtual rotation method is applied for rectification, which results in a more specific transform that has only 3 parameters, and more stability. Experimental results for real stereo images showed the presented method is efficient.     

Immunotherapy of intracranial G422 glioblastoma with dendritic cells pulsed with tumor extract or RNA

OBJECTIVE: To investigate the anti-tumor efficacy of dendritic cell (DC)-based vaccines pulsed with tumor extracts or RNA in a mouse model of intracranial G422 glioblastoma. METHODS: Bone marrow-derived DCs were pulsed ex vivo with tumor extracts or RNA. Ninety female mice harboring 4-day-old intracranial G422 glioblastomas and 126 normal mice were treated with three spaced one week apart subcutaneous injections either with PBS, unpulsed DCs, G422 tumor extracts, RNA, DCs pulsed with G422 tumor extracts (DC/extract) or with RNA (DC/RNA). Seven days after the third immunization of normal mice, the spleens of 36 of them were harvested for cytotoxic T lyphocyte (CTL) assays and the others were challenged in the brain with G422 tumor cells. All the treated mice were followed for survival. Some mice brains were removed and examined pathologically when they died. RESULTS: Immunization using DC/extract or DC/RNA significantly induced G422-specific CTL responses compared with control groups (P<0.01). Vaccination with DC/extract or DC/RNA, either prior to G422 tumor challenge or in tumor-harboring mice, significantly prolonged survival compared with other control groups (P<0.01). CONCLUSION: DCs pulsed with tumor extracts or RNA derived from autologous tumors has potential antitumor effects via activation of cell-mediated immunity. Our results suggest a useful therapeutic strategy against gliomas.     

从科学基金资助谈我国植物学基础研究的发展

通过对基金委受理和资助项目的分析发现,植物学具有几个特点:学科发展不平衡,经典与前沿并存;研究方法和手段不断发展;学科交叉呈现新的趋势,传统意义上的学科界限被打破;新的学科生长点不断涌现,热点领域增多。而我国又存在高水平植物学研究人员数量少,跟踪性项目比例依然很大,研究不系统、不深入,以及研究手段和技术方法创新不够等问题。本文认为为了促进植物学的发展,基金管理工作应重视以下3点: ( 1 )促进植物学优秀研究人才的培养; (2)要制定适合植物学发展的学科资助策略; (3)努力为科学家创造有利于创新的管理氛围。     

冷中子源两相氢热虹吸回路流动极限试验研究

针对中国先进研究堆冷中子源两相氢热虹吸回路传递管的流动极限,以R113 为工质进行了垂直管内气液两相逆流流型和液泛发生界限的试验研究.通过可视化试验发现,随着气液两相流量的增加,依次可出现平稳的下降液膜流、入口有液滴夹带的下降液膜流、入口附近局部乳沫流和全管搅拌乳沫流4 种流型.依据不同管径(32、34、45 mm)、不同压力(70~820 kPa)下的液泛试验数据,提出了一个新的预测液泛发生的关联式,并和一些著名的液泛关联式进行了比较,发现试验数据以及新关联式的预测结果和McQuillan修正关联式的预测值最为一致.所提出的关联式适用于闭式系统中具有锐边入口几何结构的垂直管内气液两相逆流液泛的预测.