丙型肝炎患者核酸定量检测与抗体水平相关性研究

目的分析丙型肝炎患者核酸定量检测(HCV-RNA)与抗体水平的相关性。方法研究共纳入104例丙肝患者,对HCV抗体水平与HCV病毒载量进行相关性分析,根据HCV病毒载量水平升高与否分组,比较两组间HCV抗体水平差异有无统计学意义。双侧P值<0.05认为差异有统计学意义。结果HCV抗体水平与HCV病毒载量呈正相关(r=0.466),HCV病毒载量正常组与升高组HCV抗体水平(S/CO值)分别为5.70±1.96 vs. 12. 84±2.76(t=-8. 350,P=0.001),当cut-off值为9. 88时,ROC曲线下面积达到最大值(AUC=0. 868),其灵敏度与特异性分别为94. 12%及73.56%。结论HCV抗体水平与HCV病毒载量呈正相关,在临床工作中,当HCV抗体水平处于较高水平时,HCV病毒载量往往也会升高,HCV抗体水平可赋予更多的临床应用价值

Effect of Sintering Temperature on Surface Morphology and Roughness of 3D-printed Silicon Ceramic Cores

单晶高温合金空心叶片是航空发动机的重要部件，其内腔结构是通过陶瓷型芯制备的。随着航空发动机推重比的提高，型芯结构越来越复杂，传统制备工艺受限，光固化3D打印陶瓷型芯技术为复杂型芯的制备提供了一种可行方案。为了改善光固化3D打印陶瓷型芯因台阶效应导致的表面粗糙度较大的问题，本研究利用固含量体积分数63%的硅基型芯浆料进行光固化3D打印型芯制备，并对型芯素坯进行了1100 ℃至1300 ℃的烧结，对烧成的硅基陶瓷型芯进行微观结构、元素分布、相组成和型芯打印面和打印堆积方向的表面形貌和粗糙度的分析。研究发现型芯打印面较为平整，无明显表面缺陷，1100、1200和1300 ℃烧结型芯的打印面粗糙度分别为1.83、1.24和1.44 &mu;m；片层堆积方向的表面有片层结构特征，片层间有微裂纹出现，1200 ℃以上烧结的型芯表面粗糙度达到空心叶片使用要求(R_(a)&le;2.0 &mu;m)。结果表明不同烧结温度影响型芯烧结过程中的液相含量、莫来石生成量、莫来石生成形态和颗粒间玻璃相的分布，从而对光固化3D打印硅基陶瓷型芯的表面粗糙度产生明显影响。光固化3D打印陶瓷型芯技术结合烧结工艺能制备出表面粗糙度完全达到先进空心叶片用硅基陶瓷型芯的表面要求。</p

中国1990和2000基准年湿地变化遥感

分别收集1990年前后和2000年前后的美国陆地卫星资料,完成了相应时期的中国全国湿地分布遥感制图.两期制图结果相比较显示,除水稻田人工湿地之外,中国的其他湿地总面积从1990基准年的355208km2下降到2000基准年的304849km2.10年间中国湿地丧失面积约为50360km2,丧失了14%.其中内陆湿地面积由318326km2减少到257922km2,减少19%;滨海湿地由14335km2减少到12015km2,减少16%;而除水稻田以外的人工湿地增加了55%,达到34911km2.湿地丧失的主要省区为黑龙江省、内蒙古自治区和吉林省.三省区天然湿地损失逾57000余平方公里.大部分丧失的天然湿地被转化为农牧用地.新增12000余平方公里的人工湿地,以渔业养殖和水库为主.在新疆、西藏和青海新增近13000余平方公里的湿地,可能由气候变暖造成冰川积雪融化所致.中国湿地减少主要是人为因素所致

John Fryer and The Translator’s Vade-mecum: the identification of the “Vocabulary of Terms in Naval Architecture"

John Fryer was one of the most important foreign translators in China after the Opium Wars. The work that is the final result of his experience at the Jiangnan Arsenal is The Translator’s Vade-mecum. Among the preparatory manuscripts of the glossaries that were published in the Vade-mecum, the author has identified the “Vocabulary of Terms in Naval Architecture.” The purpose of this article is to examine the main features of the Vocabulary, its sources and the peculiarities of the manuscript. In the first and second sections, the Vade-mecum is concisely analysed; providing numerous references and simultaneously sketching an outlook of the production and circulation of knowledge in the period considered, the author presents theoretical discussions concerning the norms of translation applied in the Vade-mecum, its purpose and the patronage of the translation activity. In the third and main section, studying the historical significance and linguistic quality of some of the translated terms annotated in the “Vocabulary,” the author compares its terminology with the concurrent Japanese one and with other Chinese relevant nomenclatures, demonstrating the complicate interaction in the “Vocabulary” between lexical innovation and recovery of existing terms