面向信息检索的藏文文本索引策略研究

互联网文本数量持续爆炸式增长,用户通过互联网查找信息变得更加困难,响应时间得不到满足。针对藏文本身的语言学特点,探讨一种面向信息搜索的藏文文本索引建立策略,建立一种高效的藏文文本索引,以提高藏文信息检索速度。     

一个新的不耐热的伤寒沙门氏菌特异性抗原(θ)的发现

我们在研究伤寒沙门氏菌保护性抗原期间,发现了一个新的不耐热的伤寒沙门氏菌特异性抗原,暂时命名为θ抗原。这个抗原存在于各种类型的伤寒沙门氏菌中,并能从Ty2菌苗株细胞提取。以不吸收的抗θ兔血清作试管凝集时,与O90l和H901菌株的凝集效价分别为1:640和1:320。但与Ty2或9,12,Vi:d:-菌株不发生凝集,这一现象以后证实是由于Vi抗原的存在。θ抗原形成凝集较幔(31℃18～24小时),其所形成的凝集块疏松,易摇散、呈半絮状。菌体经100℃30分钟加热后与θ血清不发生凝集。玻片凝集试验显示θ血清与W和V型伤寒沙门氏菌(后者须培养在含酚培养基上)在1分钟内产生明显凝集。而与大多数D群(包括D_1和D_2)沙门氏菌和其他沙门氏菌不凝集,并与下列肠杆菌科细菌亦不凝集,包括志贺氏菌属A、B、C、D群,大肠艾希氏菌O:1～25和致病性大肠艾希氏菌12个不同的血清型,3株变形杆菌以及含有α抗原的Wakefield茵。化学分析显示,粗制θ提取物含有核酸(491μg/ml)。蛋白质(39μg/ml)和KDO(23μg/ml),但不含有O-乙酰基,表明θ抗原不同于Vi抗原。作者建议以θ血清替代现用的O:9,Vi和d因子血清作为伤寒沙门氏菌的血清学诊断。并需继续查明θ抗原的化学本质。     

In vitro comparison of hepatic metabolism of 9cis-11 trans and 10trans-12cis isomers of CLA in the rat

Hepatic metabolism of the two main isomers of CLA (9cis-11 trans, 10trans-12cisC_18∶2) was compared to that of oleic acid (representative of the main plasma FA) in 16 rats by using the in vitro method of incubated liver slices. Liver tissue samples were incubated at 37°C for 17h under an atmosphere of 95% O₂/5%CO₂ in a medium supplemented with 0.75 mM of FA mixture (representative of circulating nonesterified FA) and with 55 μM [1-¹⁴C]9cis-11 trans C_18∶2, [1-¹⁴C]10trans-12cis C_18∶2, or [1-¹⁴C]oleate. The uptake of CLA by hepatocytes was similar for both isomers (9%) and was three times higher (P<0.01) than for oleate (2.6%). The rate of CLA isomer oxidation was two times higher (49 and 40% of incorporated amounts of 9cis-11 trans and 10trans-12 cis, respectively) than that of oleate (P<0.01). Total oxidation of oleate and CLA isomers into [¹⁴CO₂] was low (2 to 7% of total oxidized FA) compared to the partial oxidation (93 to 98%) leading to the production of [¹⁴C] acid-soluble products. CLA isoemrs escaping from catabolism were both highly desaturated (26.7 and 26.8%) into conjugated 18∶3. Oleate and CLA isomers were mainly esterified into neutral lipids (30%). They were slowly secreted as parts of VLDL particles (<0.4% of FA incorporated into cells), the extent of secretion of oleate and of 10trans-12 cis being 2.2-fold higher than that of 9cis-11 trans (P<0.02). In conclusion, this study clearly showed that both CLA isomers were highly catabolized by hepatocytes, reducing their availability for peripheral tissues. Moreover, more than 25% of CLA escaping from catabolism was converted into conjugated 18∶3, the biological properties of which remain to be elucidated.     

一个网站信息发布系统的设计与实现

分析并实现了基于PHP技术构建的政府信息发布系统设计模式,包括信息发布类网站系统的开发设计、总体结构、功能实现等。采用了盒式模型和MVC模式作为系统实现的核心技术。这种基于服务器储存模型的系统在响应速度上具有一定的高效性。网站设计实现后,简化了管理员对网站的更新维护工作,加快了网络信息的传播速度。     

小型农业驱动轮胎结构设计优化

介绍小型农业驱动轮胎外轮廓参数、花纹设计参数及帘线的选取。驱动轮胎行驶面较宽，ｂ／Ｂ可取０．９０～０．９５；其花纹设计既要考虑牵引性，又要考虑耐磨性，花纹块面积宜占行驶面总面积的２６％～２８％。优化后轮胎重量减轻３．８％～７．５％，成本降低２．６％～３．８％。     

面向云存储的高性能数据隐私保护方法

随着云计算和云存储技术的飞速发展,越来越多的企业和个人使用云存储来保存数据或备份数据。但用户将私有数据上传到云端的同时,也丧失了对数据的绝对控制权,用户数据的隐私保护问题成为云存储发展不得不解决的问题。为了解决这一问题,提出一种新的针对云存储的数据隐私保护方法 BSBC(Bit Split Bit Combine),它在上传前,将数据按照比特位进行拆分,重新组装后形成多个数据文件,再分别上传到云存储服务器;下载时,先将所有数据文件下载,然后通过位合并再恢复成原始文件。实验证明这种方法可以保护用户数据的隐私,同时可比传统加解密获得17~35倍的性能提升。然后将核心的位拆分、位合并代码模块用汇编语言进行优化,对汇编语言进行指令调度优化,以减少数据冲突和流水线停顿。最终,采用BSBC方法比传统加解密可以获得25~35倍的性能提升。     

Effects of conjugated linoleic acid isomers on the hepatic microsomal desaturation activities in vitro

The influence of individual conjugated linoleic acid (CLA) isomers on the Δ6 desaturation of linoleic and α-linolenic acids and on the Δ9 desaturation of stearic acid was investigated in vitro, using rat liver microsomes. The Δ6 desaturation of 18∶2n−6 was decreased from 23 to 38% when the ratio of 9cis,11trans-18∶2 to 18∶2n−6 increased from 0.5 to 2. The compound 10trans,12cis-18∶2 exhibited a similar effect only at the highest concentration. The Δ6 desaturation of α-linolenic acid was slightly affected by the presence of CLA isomers. The sole isomer to induce an inhibitory effect on the Δ9 desaturation of stearic acid was 10trans,12cis-18∶2.     

遗传算法理论及其应用研究进展

首先阐述遗传算法的原理和求解问题的一般过程;然后讨论了近年来从遗传算子、控制参数等方面对遗传算法的改进,并对遗传算法在计算机科学与人工智能、自动控制以及组合优化等领域的应用进行陈述;最后评述了遗传算法未来的研究方向和主要研究内容。     

基于GPS实时数据的在线过滤与补遗研究*

为提高GPS数据的有效性与可靠性,使之为实现实时交通流量预测与交通诱导服务,首先基于GPS历史数据,以变异系数极小化为优化目标进行GPS数据过滤模型的优选,并对实时数据缺损提出两种补遗算法;然后给出基于动态GPS实时数据的在线数据过滤与补遗一体化算法;最后结合2008年杭州市GPS历史数据对模型进行应用。结果表明,基于简单算术平均的滤波模型即为GPS数据过滤的最佳模型;基于时间序列缺失数据的快速补遗算法能够很好地满足实时预报要求,实现快速补遗。