89 research outputs found

    How Should Chinese Enterprises Face Anti-Dumping

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    随着贸易的全球化,国与国之间倾销与反倾销的商战也越演越烈。本文通过分析中国产品遭受反倾销的原因,提出了如何面对反倾销的一系列做法。With trades becoming global, dumping and anti-dumping between different countries are getting fiercer and fiereer accordingly.This paper,based on an analysis of the causes of the dumping of goods, comes up with a series of measures with regard to anti-dumping

    SAR image despeckling using nonsubsampled Contourlet transform

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    中文摘要: 提出了一种基于无下采样 Cont ourlet变换 (NSCT)的合成孔径雷达 ( S AR)图像去噪方法。首次在理论上证实了 S AR图像取对数后无下采样 Cont ourlet系数服从广义高斯分布 ,从而提出采用贝叶斯阈值方法估计不含噪声的无下采样 Cont ourlet系数 ,达到去除噪声的目的。仿真和实际实验结果表明 ,该方法在噪声平滑、 边缘和纹理保护等方面优于其他方法。由于无下采样 Cont ourlet变换不进行下采样 ,该方法能够避免其他进行严格下采样的变换去噪时所引入的人工痕迹。 英文摘要:Abstract: A nonsubsamp led Cont ourlet transform (NSCT) based des peckling method for synthetic aperture radar ( SAR) i mages is p resented . It is derived in theory for the first ti me that the coefficients of l ogtransfor med SAR images decomposed by NSCT obey general Gaussian distributi on, so Bayesian shrinkage fact or is adop ted t o esti mate noise free NSCT coefficients . Simulati on and experi ments demonstrate that the visual quality of the results is superi or to other des peckling methods in terms of both backgr ound s moothing, preservati on of edge sharpness and texture .The absence of deci mati on in Cont ourlet decompositi on avoids artificial i mpair ments often intr oduced by other critically subsamp led transfor m methods .基金项目:国家自然科学基金 (10605019)、 福建省自然科学基金 (2006J0227)、 厦门大学 985二期信息创新平台 ( 00002 X07204)、 厦门大学科技创新项目资

    Numerical Simulation of the Air Flow Spiral Inducing in Cooling Tower

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    使用FLUENT软件, 对水冷火电厂的水冷塔换热进行了数值模拟, 解决了物模实验难以模拟热力因素的困难. 同时还对采用"空气涡流导引装置技术"的水冷塔和传统水冷塔, 在不同环境风影响下的换热效率进行了对比. 结果表明, 采用"空气涡流导引装置技术"的水冷塔换热效果优于传统水冷塔, 抵抗大风的能力更

    光学微球腔谐振模式间隔参数的一种简便计算方法

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    从光学微球腔谐振模式的本征方程出发,提出了一种利用求导法计算谐振模式间尺寸参数(x)间隔的有效方法。在Lam求得的尺寸参数计算公式基础上,依据谐振模式角量子数(l)必须为整数且远远大于1的性质,相邻模式(Δl=1)间的尺寸参数间隔可近似表示为相应尺寸参数的导数,从而可利用求导法计算谐振模式之间的尺寸参数间隔。研究表明,径向量子数i=1的谐振模式的尺寸参数间隔与Mie散射理论求得的精确数值解之间的相对误差在0.05%以内,并且与实验测量数据基本一致。求导法因不需要进行繁琐的级数展开,从而大大简化了计算程序,为光学微球腔的实验研究提供了理论指导

    一种联合检测乙型肝炎病毒前S1抗原与核心抗原方法的建立及其与病毒核酸检测结果的一致性

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    本研究以与血清中HBV DNA含量高度相关的两种HBV抗原(前S1抗原与核心抗原)为靶标,建立了联合检测这两种HBV核酸相关抗原(NRAg)的双抗体夹心法ELISA试剂。对系列稀释血清的检测表明,该试剂的平均分析灵敏度为103.2基因组拷贝/mL(95%可信限102.2-4.2基因组拷贝/mL),显著高于前S1抗原或核心抗原的单独检测。对994份HBsAg阴性血清的检测结果表明NRAg ELISA的特异性为99.7%(95%可信限:99.1%~99.9%)。对271份临床慢性肝炎血清进行检测,结果NRAg ELISA与HBV DNA结果的总符合率达96.3%(95%可信限:93.3%~98.2%),NRAg ELISA的读值/临界值比(S/CO)与HBV基因组拷贝数呈正相关。利用NRAg试剂,发现了1例HBsAg"a"抗原表位突变的变异株。这些结果显示HBV NRAg ELISA与HBV DNA具有高度相关性,并能够检测出HBsAg抗原变异株,有望成为HBsAg变异株筛选的有力工具,并为广大基层医疗单位提供一种便捷的替代HBV DNA定性检测的手段

    江苏省部分地区散发戊型肝炎流行病学及病毒基因型

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    目的了解江苏省部分地区散发戊型肝炎病例的流行特征及病毒基因型。方法在江苏省部分地区开展为期一年戊型肝炎病例监测,用酶联免疫吸附试验(enzyme-linked immunosor-dent assay,ELISA)对各医疗单位报告的急性肝炎病例进行血清学分型,对其中确诊为急性戊型肝炎病例进行流行病学分析以及戊型肝炎病毒(hepatits E virus,HEV)RNA检测和序列分析。结果男女戊型肝炎病例比例为4.4∶1,84.0%的病例集中在40岁及以上的年龄组,全年均有戊型肝炎病例发生,70.5%的病例集中在上年12月份至次年的4月份间;HEV基因分型检测结果为HEV-1型与HEV-4型,所占比例分别为5.1%、94.9%。结论江苏省戊型肝炎发病比例男性高于女性,多见于40岁以上人群,冬春季节发病较高,戊型肝炎病毒株以HEV-4型为主

    两种戊型肝炎IgG抗体检测试剂的比较

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    目的比较2种国产戊型肝炎IgG抗体诊断试剂(E2-IgG和X-IgG)的特异性与敏感度。方法利用2种试剂对2006年江苏省某市普通人群的流行病调查血清标本460份和经过巢式逆转录聚合酶链式反应(nest-RT-PCR)鉴定为HEV核酸阳性的临床戊型肝炎患者血清标本72份进行平行检测,并以免疫印迹实验(Westernblot,WB)和中和单抗阻断试验进行验证。结果1.460份流行病调查血清标本中WB阳性188份。2.188份WB阳性标本中E2-IgG的检测敏感度为99.5,特异度为99.6,阳性预测值99.5,阴性预测值99.6,准确性99.6;X-IgG的检测敏感度为21.3,特异度为97.4,阳性预测值85.1,阴性预测值64.1,准确性66.3。3.E2-IgG阴、阳性A450/A620值的分布在临界值附近分界明显,小于临界值的A450/A620值取对数后呈正态分布,而阳性血清A450/A620值的高低与其WB的反应强度正相关。4.E2-IgG阳性、X-IgG阴性的血清共148份,中和单抗阻断阳性率为98,WB阳性率99.3。5.经PCR鉴定为HEV核酸阳性的急性戊型肝炎患者血清中E2-IgG敏感度98.6,X-IgG敏感度80.6(χ2=10.7,P<0.01)。结论E2-IgG在不同人群中均能较好的反映体内戊型肝炎抗体存在的真实情况

    Analysis of partial sequences of Hepatitis E virus isolated from human and swine in a certain area of Jiangsu province

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    目的:调查了解江苏省某农村地区人源与猪源戊型肝炎病毒(HEV)的相关性。方法:应用逆转录-巢式聚合酶链法(rT-PCr)对同一地区内一般人群中HEV IgM阳性者、急性戊型肝炎患者血标本和生猪胆囊标本进行HEV rnA检测,并对HEV rnA阳性标本进行克隆测序和序列分析。结果:一般人群中检出的HEV基因1、4型比例相近,临床散发性戊肝病例绝大部分为HEV-4型病毒感染所致(95.24%);生猪胆汁标本PCr阳性率为12.11%,猪源HEV基因分型均为HEV-4型;分离于人和生猪的HEV-4型病毒高度同源,同源性81%~97%。结论:该地区人群HEV基因分型以HEV-4型为优势毒株;猪源HEV均为基因4型;人源和猪源的HEV-4型病毒高度同源,猪是当地HEV主要宿主动物之一。Objective:To explore the correlation between swine and human hepatitis E virus(HEV) in Jiangsu province.Methods:Specimens collected from HEV-IgM positive people of the general population,patients with acute hepatitis E and cholecyst from swine in the same area,were detected for HEV RNA by nested reverse transcription polymerase chain reaction(RT-PCR).HEV-positive samples were further analyzed by direct nucleotide sequencing.Results:Among the HEV IgM carriers,8 positive cases were identified,and the subtype of HEV were type 1 and type 4.The majority cases of clinical sporadic HEV were type 4(95.24%).The HEV-positive rate of swine bile samples was 12.11%,and the virus genotype was type 4.The type 4 HEV of human and swine showed a high degree of homology(81%~97%).Conclusion:Both HEV-1 and HEV-4 were found in human in this area with the dominant type of HEV-4.All the swine HEV-positive samples showed HEV-4 genotype.The HEV-4 of human and swine in the Dongtai area showed a high degree of homology.These findings suggest that swine may be one of the main hosts of HEV in this region

    戊型肝炎病毒基因1型和基因4型中和表位区域分子差异研究

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    戊型肝炎病毒(HEV)根据易感宿主的差别可以分为两大类:一类只分离自人的H(Human)类,包括HEV-1和HEV-2;一类为人畜共患的Z(Zoonosis)类,包括HEV-3和HEV-4。本研究通过比较这两类HEV的ORF2aa368~606区段,发现存在4个类保守的差异位点,均位于HEV的主要中和表位区域aa459~606,分别是aa483、aa492、aa497和aa599;对这四个位点进行定点替换突变,以一组能够捕获HEV-1和/或HEV-4的单克隆抗体比较各种突变体的免疫反应性,结果表明仅aa497的差异造成了这两类HEV中和表位构象的部分差异,提示aa497及其相关的病毒表面结构差异在H类和Z类HEV宿主选择中可能扮演重要角色

    Analysis on the epidemiological characteristics of the sporadic cases with hepatitis E infection in the rural area in Jiangsu province

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    目的了解江苏省农村散发性戊型肝炎的流行病学特征。方法通过建立覆盖市、镇、村三级医疗卫生服务机构的疑似肝炎主动监测网络,系统全面地监测戊型肝炎病例的发病情况。结果主动监测网络的敏感性明显高于网络报告系统,能更加准确、全面地掌握戊肝的发病规律。结果显示戊型肝炎病例占疑似急性肝炎病例的26.7%,男性戊肝发病率高于女性(P<0.01);发病随着年龄增长而上升,多见35岁以上人群;全年均有发病,冬春季节较高;戊型肝炎病毒株HEV1、4型并存,但以HEV4型为主(92.5%)。结论疑似肝炎主动监测系统数据显示目前戊肝发病率有被低估的风险。To understand the epidemiological characteristics of the sporadic cases with hepatitis E infection in the rural area of Jiangsu province,the prevalence of hepatitis E infection was surveyed systemically and completely through the initiatively monitoring system for the suspected cases of hepatitis E covering the city,town and village levels of medical and health service organizations.It was found that the initiatively monitoring system for suspected hepatitis E cases reflected the incidence of hepatitis E more accurately and comprehensively and was proved to be more sensitive than the network reporting system.The cases with hepatitis E accounted to 26.7% of the suspected cases with acute hepatitis and they were more frequent in male than in female.The incidence of hepatitis E increased with advance of age and most of cases occurred with age over 35.Estimated incidence was stable on the whole year,but rose up in winter and spring.The HEV type 1 and type 4 co-existed,but the HEV type 4 was proved to be the main type(92.5%).From the above observations,it seems that the initiatively monitoring system for the suspected cases of hepatitis E may be under-estimated for the risk of the hepatitis E infection in rural area of Jiangsu province.国家高技术研究发展计划(863计划)(2006AA02A209)资
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