排序方式: 共有22条查询结果,搜索用时 15 毫秒
1.
一个多元校正的稳健诊断新方法 总被引:1,自引:0,他引:1
提出一种新的稳健诊断方法,与最小二乘估计结合进行混合物光谱中非线性点的诊断。文中探讨了该方法的性能,用计算机数字模拟及实际多组分光谱体系夺其进行检验,展示了此诊断方法在分析化学计量学中实际应用的可行性。 相似文献
2.
SF,F_2和SF_2分子的结构与势能函数 总被引:2,自引:0,他引:2
在6 311+G(2df,2pd) 和6 311+G(p,d)基组水平上,采用二次组态相互作用(QCISD)方法,对 SF2,SF,F2 分子进行了理论计算,得到了它们的结构参数、能量、谐振频率和力学性质,其结果与实验值符合得非常好.在此计算的基础上,用二原子分子Murrell Sorbie势能函数得到了 SF和 F2 分子的势能曲线,并推导出其光谱数据和力常数, 通过多体展式理论方法推导出了SF2 分子的解析势能函数,该函数正确反映了SF2 分子的结构特征和能量变化. 相似文献
3.
The synthetic utility of sulfur ylides in orgnic chemistry has been successfully explored over the past several years and has provided an easily accessible route to a number of functional groups,4 including cyclopropanes,5 and optically active epoxides6. 相似文献
4.
Lorch JM Meteyer CU Behr MJ Boyles JG Cryan PM Hicks AC Ballmann AE Coleman JT Redell DN Reeder DM Blehert DS 《Nature》2011,480(7377):376-378
White-nose syndrome (WNS) has caused recent catastrophic declines among multiple species of bats in eastern North America. The disease's name derives from a visually apparent white growth of the newly discovered fungus Geomyces destructans on the skin (including the muzzle) of hibernating bats. Colonization of skin by this fungus is associated with characteristic cutaneous lesions that are the only consistent pathological finding related to WNS. However, the role of G. destructans in WNS remains controversial because evidence to implicate the fungus as the primary cause of this disease is lacking. The debate is fuelled, in part, by the assumption that fungal infections in mammals are most commonly associated with immune system dysfunction. Additionally, the recent discovery that G. destructans commonly colonizes the skin of bats of Europe, where no unusual bat mortality events have been reported, has generated further speculation that the fungus is an opportunistic pathogen and that other unidentified factors are the primary cause of WNS. Here we demonstrate that exposure of healthy little brown bats (Myotis lucifugus) to pure cultures of G. destructans causes WNS. Live G. destructans was subsequently cultured from diseased bats, successfully fulfilling established criteria for the determination of G. destructans as a primary pathogen. We also confirmed that WNS can be transmitted from infected bats to healthy bats through direct contact. Our results provide the first direct evidence that G. destructans is the causal agent of WNS and that the recent emergence of WNS in North America may represent translocation of the fungus to a region with a naive population of animals. Demonstration of causality is an instrumental step in elucidating the pathogenesis and epidemiology of WNS and in guiding management actions to preserve bat populations against the novel threat posed by this devastating infectious disease. 相似文献
5.
对传统GM(1,1)沉降预测模型进行分析后,发现参数采用固定值与实际情况不符,会影响预测精度.为弥补这一不足,对传统灰色模型进行改进,假定参数是时间的连续函数,并对之做了拟合,提出含时变参数的GM(1,1)预测模型.实例证明此模型比传统GM(1,1)模型精度更高. 相似文献
6.
优秀男子手球运动员比赛期间部分生化指标监控研究 总被引:1,自引:0,他引:1
顾建仁 《南京体育学院学报(自然科学版)》2011,10(1):26-28
为了了解优秀男子手球运动员在比赛期间的部分生化指标的变化,为运动员在以后的比赛中做好必要的准备。对男子手球比赛期间运动员的wbc、Rbc、Hb、Hct、BUN、CK进行了监控,结果表明,通过合理的营养品补充,可以较好地维持运动员在比赛期间的wbc、Rbc、Hb、Hct、BUN水平,但CK的变化较大,积极性的休息是降低运动员CK值的有效手段,运动员比赛期间高CK值是手球比赛的特点之一。 相似文献
7.
应用PCR技术从人胎肺cDNA文库中扩增tumstatin基因编码序列,克隆至pET-3c载体构建非融合表达的重组质粒pET-3c-tum,并在大肠杆菌E.coli B121(DE3)中获得高效表达。表达蛋白经SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)分离、切胶回收后免疫新西兰大白兔,获得ELISA效价高达1:1000的特异性兔抗人tumstatin抗血清。 相似文献
8.
Inpreviouspaperswehavereportedtheisolationandidentificationofescinsla,fo,IVa.IVbandIVel2.Nowwedescribethestructureelucidationofthreemorenewtriterpenoidsaponins.namedescinsIVc(l),IVd(2)andIVf(3).CompoundIwasisolatedaswhiteamorphouspowder.HR-SI-MSrevealedthecompositionofC,,H,,O,,bymolecularionpeakatm/z1129.5438.Comparedwiththe:3CandiHNMRspectraofescinla,compoundIisalsoaglycosideofprotoaescigeninacylatedbythetigloylandtheacetylgroup.Thesignificantdifferencesbetweenthemwerethechemicals… 相似文献
9.
中国近代的一百年间,列强打开国门,军阀混战不息。国门洞开促进了资本主义工商业的发展,引进了西方的企业经营管理思想,使中国传统管理思想融进了新鲜的内容。这一时期的管理思想代表人物有林则徐、魏源、李鸿章、张之洞、康有为、梁启超、孙中山、廖仲恺、蔡元培、黄炎培、蒋介石、张謇、穆藕初、荣宗敬、荣德生、刘鸿生、卢作孚等。 相似文献
10.
采用单光束的Z扫描技术研究了GaAs颗粒镶嵌薄膜的非线性光吸收和非线性光折射特性,获得了增强的三阶光学非线性响应.实验测得的非线性折射率系数为 10-3esu和非线性光吸收系数为10-1cm/W量级.研究了产生饱和吸收时的光跃迁选择定则,观察到了饱和吸收现象和双激子态的双光子吸收现象,实现其饱和吸收和双光子吸收所需的辐射光强小于104w/cm2结果表明:增强主要起源于量子限域效应,在强限域条件下,库仑作用效应被更强的限域作用所掩盖.GaAs颗粒表现出类似于二能级系统的光学非线性响应特征. 相似文献