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1.
介绍了不确定度理论及其评定方法,结合车辆碰撞事故的具体特点,给出了基于能量守恒的车速计算表达式.通过选择适当的输入参数作为不确定因子,分别计算各分量等效速度标准不确定度.考虑不确定度累积和传播,得到车速输出结果的合成标准不确定度和展伸不确定度,以此检验事故再现结果的准确程度.通过具体事故案例的分析计算和计算机检验,验证该方法的适用性. 相似文献
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为了明确几种分析方法对杂种棉后代综合评价的异同,于2002-2003年通过聚类分析、关联度分析以及多目标综合值评定分析原理对10个杂种棉后代在不同生态点的主要农艺及经济性状进行了分析.结果表明:3种分析方法对杂种棉后代的综合评价趋势基本上一致.从纤维品质来看,以湘Z-010,湘Z-004,湘Z-008,湘Z-007纤维品质较好.从产量性状来考虑,以湘Z-001,湘Z-002,湘Z-004产量较高.从湖南定位50-60支纱区划方针和产量性状来看,以湘Z-004表现最好,属于高产优质品种. 相似文献
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在市场经济迅速发展、种子生产、流通量不断增加和加入WTO的新形势下,充分提高湖南省棉种的质量水平,推动棉种产业化的健康发展,对农民增收、农村稳定具有重大的现实意义。本文简要介绍了提高湖南棉种质量水平的紧迫性和可行性。在此基础上提出了提高棉种质量水平促进产业化发展的几点建议。 相似文献
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AIM and METHODS: Total RNA was extracted from 6th rat subcultured pulmonary artery smooth muscle cells(PASMC) exposed to continual chronic hypoxia or normoxia and the effects of chronic hypoxia on the changes of Kv1.3,Kv2.1,Kv3.1 mRNA in cultured PASMC induced by acute hypoxia were studied by semiquantitative RT-PCR in vitro. RESULTS:①Kv1.3,Kv2.1,Kv3.1 genes were found to be expressed in PASMC of rats exposed either to hypoxia or normxia.②The expression of Kv2.1 and Kv3.1 in 6th subcultured of PASMC in normaxia group could be upregulated by exposure to acute hypoxia,the levels of Kv2.1 and Kv3.1 mRNA were significantly increased from 0.646±0.092, 0.782±0.104 to 1.059±0.134, 0.985±0.116,respectively (P<0.01,n=5). ③PASMC cultured continuously in chronic hypoxia for 6 subcultures and then exposed to normoxia for 12 h,thereafter the expression of Kv2.1 and Kv3.1 were downregulated by acute hypoxia for 6 hours.The level of Kv2.1 mRNA was significantly decreased from 1.008±0.117 to 0.649±0.097 (P<0.01,n=5). CONCLUSION:Kv2.1,Kv3.1 genes might be oxygen sensitive genes.Chronic hypoxia might change the response of these Kv genes of PASMC to acute hypoxia and down-regulate its expression,which might probably decrease the role of Kv in HPV. 相似文献
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选用中华硬蜱105kD柱层析纯化抗原对新西兰兔进行免疫接种,再用二棘血蜱进行叮咬,并与单纯二棘血蜱叮咬组和佐剂对照组进行对比,以探讨不同种属硬蜱之间的交叉免疫抗性。结果显示:单纯二棘血蜱叮咬组吸血量为181 3±44 3mg,而二棘血蜱叮咬由中华硬蜱105kD纯化抗原免疫接种组和佐剂对照组新西兰兔后其吸血量分别为102 1±25 3mg和168 5±40 9mg,纯化抗原免疫接种组较单纯二棘血蜱叮咬组和佐剂对照组吸血量分别下降43 7%和39 4%(P<0 01)。同时,纯化抗原免疫接种组也较单纯二棘血蜱叮咬组和佐剂对照组产卵量有显著下降。该研究结果表明中华硬蜱和二棘血蜱之间存在着交叉免疫反应。 相似文献
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DU Yi-mei TANG Ming LIU Chang-jin HONG Zhi-gang KE Qin-mei DI Jiu-fang LUO Hong-yan HU Mou-xian HU Xin-wu XI Jiao-ya TANG Bi Jurgen Hescheler 《园艺学报》2004,20(9):1537-1541
AIM: To determine the role of Kv1.2, Kv1.5, Kv2.1 in the hypoxia pulmonary vasoconstriction (HPV). METHODS: Male Wistar rats were divided into two groups: normoxic group and hypoxic group. The single smooth muscle cell was obtained from pulmonary artery of Wistar rats with acute enzymatic digestion method. The conventional whole-cell patch clamp technique was used to record the resting membrane potential (Em) and the potassium currents of voltage-gated potassium channel (IKv) in rat pulmonary arterial smooth muscle cells (PASMC). Intracellular application of Kv1.2/Kv1.5/Kv2.1 antibodies (1∶125) was conducted through the whole-cell patch clamp system. RESULTS: ① Em of PASMC was depolarized after 24 h hypoxia compared with that of control cells . IKv of PASMC was decreased after 24 h hypoxia, . ② The mixture of Kv1.2/Kv1.5/Kv2.1 antibodies depolarized Em and inhibited IKv in PASMC from normoxic rat, whereas the mixture of Kir2.1/Kir2.3/Kir4.1 antibodies had no effects on them. ③ The mixture of Kv1.2/Kv1.5/Kv2.1 antibodies and the mixture of Kir2.1/Kir2.3/Kir4.1 antibodies had no effects on IKv and Em from rats hypoxic for 24 h. CONCLUSION: Kv1.2, Kv1.5, Kv2.1 might be oxygen sensitive potassium channels which mediated HPV. 相似文献
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To study the effect of luteolin on blood indexes,liver and kidney in mice with acute mercury poisoning,28 mice were randomly divided into four groups:Control group (intraperitoneal injection 0.9% saline),luteolin group (lavage 100 mg/kg luteolin),mercuric chloride group (intraperitoneal injection 4 mg/kg mercury chloride) and mercury chloride+luteolin group (intraperitoneal injection 4 mg/kg mercuric chloride,lavage 100 mg/kg luteolin).The activities of ALT in serum,AST,CREA and BUN contents,blood WBC,RBC,HGB content and GSH and MDA contents of liver tissue were detected.Morphological changes of liver and kidney tissues were observed.The results showed that compared with the control group,the activities of ALT and AST of mercuric chloride group were extremely significantly increased (P < 0.01),serum CREA,BUN,blood WBC and liver tissue MDA contents were significantly increased (P < 0.05) while blood RBC,HGB and liver tissue GSH contents were significantly decreased (P < 0.05).Liver,kidney pathological changes were obviously.Compared with mercuric chloride group,the activities of ALT,AST in serum,CREA,BUN,blood WBC and liver tissue MDA contents of mercuric chloride+luteolin group were significantly decreased (P < 0.05),while blood RBC,HGB and liver tissue GSH contents were significantly elevated (P < 0.05).Liver,kidney pathological changes were attenuated obviously.The poisoning were characterized by inflammation and the occurrence of anemia when acute mercury poisoning occurred,liver and kidney showed different degrees of injury in mice.Luteolin could reduce the toxic effects of acute mercury poisoning on blood,liver and kidney. 相似文献
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以进口鱼粉和豆粕为饲料蛋白源,研究了6种蛋白水平(分别为27%、30%、33%、36%、39%和42%)的等能饲料对芙蓉鲤鲫幼鱼增重和肠道、肝脏消化酶活性的影响。结果表明,饲料蛋白水平的增加,显著地提高了鱼体增重率、特定生长率、饲料效率、肥满度(P<0.05),并降低了饵料系数和脏体比,还显著地提高了肠道组织蛋白酶、食糜蛋白酶和GOT及GPT活性(P<0.05)。随着饲料中蛋白水平的上升,肝脏蛋白酶和食糜、肠道组织、肝脏淀粉酶活性无显著性差异(P>0.05)。 相似文献