Query expansion based on semantics and statistics in Chinese question answering system

In Chinese question answering system, because there is more semantic relation in questions than that in query words, the precision can be improved by expanding query while using natural language questions to retrieve documents. This paper proposes a new approach to query expansion based on semantics and statistics Firstly automatic relevance feedback method is used to generate a candidate expansion word set. Then the expanded query words are selected from the set based on the semantic similarity and seman- tic relevancy between the candidate words and the original words. Experiments show the new approach is effective for Web retrieval and out-performs the conventional expansion approaches.     

Involvement of NADPH oxidase NtrbohD in the rapid production of H2O2 induced by ABA in cultured tobacco cell line BY-2

The mechanisms for the production of hydrogen peroxide (H₂O₂) induced by abscisic acid (ABA) were investigated in suspension culture cells of tobacco BY-2 cells. The results showed that the immediate generation of H₂O₂, which was mainly derived from superoxide dismutase-catalyzed dismutation of superoxide radical, was significantly induced by ABA. Furthermore, treatment of the cultured tobacco cells with ABA resulted in a time-dependent quick increase in plasma membrane (PM) NADPH oxidase activity, which coincided on time and magnitude with the elevation in ABA-induced accumulation of H₂O₂. Moreover, these enhanced effects were pronouncedly inhibited by two NADPH oxidase inhibitor, diphenylene iodonium and imidazole, suggesting that PM NADPH oxidase is involved in the rapid accumulation of ₂O₂ in cultured tobacco cells. In addition, analysis of the expression level of NtrbohD, a PM NADPH oxidase gene in tobacco, by RT-PCR and protein gel blot revealed that the gene at both mRNA and protein levels was upregulated by ABA, indicating that NtrbohD participates in the ABA-stimulated rapid production of H₂O₂ in tobacco culture cells. Taken together, these findings suggest that ABA induces the rapid accumulation of reactive oxygen species via NADPH oxidase in suspension culture cells of tobacco, and that NADPH oxidase and H₂O₂ appear to be important components in ABA signal transduction pathway in plants.     

实行列式的几个不等式

给出实矩阵的几个不等式,这些不等式推广了[1-4]中的若干结论.     

对高硫煤矿矿井水处理技术的探讨

通过对目前我省矿井水净化处理技术现状和存在的主要问题的阐述,探讨了高硫煤矿矿井水中的主要污染物及相应的处理措施,提出可行的技术工艺方案.     

民族地区农地使用权的用益物权探讨

土地所有权在我国大陆的主体是国家和集体。农地使用权实质上就是土地的用益物权。可以尝试构建民族地区农村土地使用的地上权,考虑设立民族地区农村土地使用的永佃权,大胆推行民族地区农村土地使用的地役权。     

基于WebGIS的地价管理系统设计

阐述了基于WebGIS地价管理系统的设计原则、系统架构和功能,分析了地价管理系统的技术特点。     

基于装机功率的并联电动平台结构参数优化

建立了4TPS-PS并联电动平台的运动学模型;推导了电动缸速度、输出力及平台功率的公式,分析了平台装机功率、使用功率等影响因素;提出以装机功率为优化指标,分析其与目前常用的灵活度指标的关系及区别.采用遗传算法进行平台结构优化设计,仿真计算了各自由度运动消耗功率与结构参数的关系,为各向功率需求不同的平台结构优化设计提供依据,并提出了减小平台功率、提高效率的方法.     

陶瓷材料电火花加工技术及研究进展

综述电火花加工技术在加工陶瓷方面的研究和应用,主要有电火花线切割加工、电火花成型加工和辅助电极电火花加工等几种方法,显示电火花加工技术在陶瓷加工领域中加工精细陶瓷零件的应用前景,并指出该技术在尖端陶瓷加工应用中存在的电磁放电状态难于控制的问题,未来的发展趋势是进一步加强人工智能化控制.     

川剧的艺术特色

本文以对川剧的各项特殊技巧和川剧唱腔的一些特点进行分析,进一步了解川剧的艺术特性,让川剧艺术得以发扬光大.     

阴道念珠菌病患者阴道分泌物念珠菌培养鉴定及药敏分析

目的：了解大理地区妇科女性患者阴道分泌物念珠菌检出状况、菌群分布及对常用抗真菌药物的敏感性。方法：取有自觉阴道症状到妇科门诊就诊患者的阴道分泌物进行念珠菌培养、鉴定和药敏试验。结果：192份标本中念珠菌阳性标本55例,检出率28．6％,汉族和少数民族妇科门诊女性患者阴道分泌物念珠菌检出率分别为32．2％和25．7％,差异无显著性（P=0．324）;56株念珠菌中白色念珠菌32株、光滑念珠菌12株、克柔念珠菌5株、热带念珠菌4株、其它2株。56株念珠菌对KETO、FCZ、5-FC和Amb的耐药率最高的是KETO,达73．2％;最低的是Amb,无耐药株。结论：外阴阴道念珠菌病是妇科门诊的常见疾病,白色念珠菌仍是主要致病菌,光滑念珠菌感染逐渐增多。本地区妇科患者阴道异常分泌物检出念珠菌对常用抗真菌药物酮康唑存在普遍耐药现象,对两性霉素B基本无耐药株产生。