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通过分析2004年8~10月西太平洋“北斗双星”有源定位及DGPS动态定位试验数据,讨论了“北斗双星”有源定位系统相对于DGPS的定位误差,构建了“北斗双星”有源定位系统在西太平洋试验海域的WGS-84与1954年北京坐标系统间的坐标转换模型。研究表明,“北斗双星”有源定位系统在试验海区的定位精度约为±37.54 m。 相似文献
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目的:探讨透骨血竭散外敷对大鼠类风湿性关节炎(RA)的治疗作用及机制。方法:将SPF级雄性SD大鼠40只随机分成正常组、模型组、阳性对照组、透骨血竭散组,每组各10只。除正常组外,其余各组大鼠均予Ⅱ型胶原诱导性关节炎造模法建立RA模型。确定造模成功后第2天开始进行药物干预,阳性对照组予扶他林软膏外敷,透骨血竭散组予自制透骨血竭散外敷,连续14d,正常组、模型组不予处理。观察各组大鼠关节红肿情况;腹主动脉取血,采用ELISA法检测血清中肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)的表达;滑膜免疫组化分析重组人血管内皮生长因子(VEGF)、血清载脂蛋白-1(ApoA-1)的阳性表达。结果:各造模组大鼠每周模型关节炎指数(AI)评分均≥6分,均有明显的RA临床症状和病理学改变;模型组IL-1β、TNF-α的表达量均高于正常组,差异有统计学意义(P<0.05)。与模型组比较,阳性对照组、透骨血竭散组大鼠IL-1β、TNF-α表达量降低,透骨血竭散组低于阳性对照组,差异均有统计学意义(P<0.05);各组大鼠滑膜APOA-1m RNA表达量差异无统计学意义(P>0.05);阳性对照组、透骨血竭散组VEGF mRNA表达量均明显低于模型组(P<0.05),透骨血竭散组低于阳性对照组,差异均有统计学意义(P<0.05)。结论:透骨血竭散外敷可通过抑制IL-1β、TNF-α及VEGF mRNA的表达量发挥治疗RA的作用,其对滑膜APOA-1的表达无明显影响。 相似文献
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As a daily necessity and an important cash crop in China and many other countries, tea has received increasing attention. Using production concentration index model and industry' s barycenter theory, we analyzed the spatio-temporal distribution of tea production and barycenter movement trajectory of tea plantations and production in China between 1986 and 2015. Driving forces of the movement were also analyzed. From 1986 to 2000, tea production in China's Mainland of grew slowly(by 210×10~3 t). The continuous increase in tea yield per unit area was the primary contributor(more than 60%) to the growth in tea production during this period. Since China joined the World Trade Organization(WTO) in 2001, tea production has grown rapidly, by 1.59×10~6 t between 2001 and 2015. The increase in the tea plantations area is the main contributor. Over the last 30 years, the barycenters of tea production in China have moved westward from the Dongting Lake Plain to the eastern fringe of the Yunnan-Guizhou Plateau. Guizhou, Guangxi, and Sichuan in southwestern China have gradually become regions of new concentrated tea plantations and main tea production provinces. Lower cost of land and labor in southwestern China are the main drivers of the westward movement of China's tea industry. In addition, supportive policies and the favorable natural geographical environment contribute to the westward movement of tea industry. Our research highlights the spatio-temporal variation of China's tea production in the last three decades. The result indicates importance to make appropriate policies to promote the development of tea industry in China. 相似文献
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