应用复合极值理论计算VaR1

本文介绍了一种复合极值理论,并将其应用到VaR的计算上。实际中大的损失发生的频率也是风险的一种度量,在应用复合极值理论方法计算VaR时,我们第一次将在一定时期内金融资产的损失率超过一定阈值的次数的分布和收益率的分布结合了起来,对欧元/人民币、日元/人民币两种汇率进行了VaR的计算,经过实证分析,得到了一些有意义的结果。     

Nd：YAG激光器中的自锁模

本文报道在Nd:YAG激光器中首次获得的自锁模脉冲序列.自锁模是由于Nd:YAG棒中的自相位调制引起的.在主被动对撞锁模运转情况下,自锁模对脉冲波形有较大的影响.     

Ar+激光激发的LiArA2Ⅱ→X2∑漫射谱发射

用Ar⁺的457.9,476.5,496.5,514.5nm激光激发充有Ar气的Li热管,获得Van der Waal's分子LiAr在650—760nm波长范围A²П→X²∑的漫射发射光谱。讨论了产生这种发射的动力学机制。 关键词：     

一维纳米固体的电子结构

本文通过计算一维纳米固体模型的电子态密度,针对颗粒大小、颗粒界面无序度等物理量,讨论了一维纳米固体的电子结构。结果表明颗粒大小对电子能态结构影响较大,而颗粒界面无序度主要引起能带宽度和态密度大小的变化。 关键词：     

CYTOLOGIC AND EMBRYOLOGIC STUDIES ON APOMICTS DISCOVERED FROM MALE STERILITY LINE C1001 IN RICE (Oryza sativa L.)

Cytologic and embryologic studies on the reproductive pattern of male sterility line C1001 in rice (Oryza saliva L.) indicated that several types of apomixis were discovered in partial strains of male sterility line C1001 in rice. Under a fully separate condition, two possible apomixis embryogenesis ways in the ovules were observed: One way was that the embryo was initiated from the somatic cells of the ovules, and then pushed against the embryo sac to develop into a mature embryo. The other way was that the embryo was from the unfertilized egg cell or one of synergids, and then developed into a mature embryo in the form of haploid parthenogenesis without forming endosperm. Besides, the antipodal cells migrated in the embryo sac, and their cytoplasm became thin and vacuolated while mitosis was taking place, giving rise to a multicellular structure or a group of large cells each containing several nuclei. This paper also discusses the significance and patterns of apomixis in rice C1001.     

织构C60薄膜的生长与光致发光特性

用Hot Wal方法，在氟金云母单晶上生长出了（111）织构的C₆₀薄膜．用X射线衍射、Raman散射、扫描电子显微镜和原子力显微镜研究了织构C₆₀薄膜的结晶质量和结构特性．测量了织构C₆₀薄膜在室温300K和低温77K的光致发光光谱．对所得结果进行了分析与讨论 关键词：     

金属与金刚石薄膜接触的电学特性研究

用热丝辅助化学汽相沉积技术在Si衬底上合成了含少量受主型杂质的近于本征的金刚石薄膜，并研究了三种金属（Cu，Ag和Al）与它接触的电学特性，以及退火对接触特性的影响．结果表明Cu，Ag与金刚石薄膜接触的电学特性比较类似，而Al则明显不同；而且退火对它们的接触特性影响很大 关键词：     

合浦珠母贝(Pinctada martensii,Dunker)珍珠囊体外预培育的初步研究

０．３％胰蛋白酶液（２５℃）消化外套膜组织的第５～１５ｍｉｎ时间段所收获的细胞产物中，表皮细胞具有最高的纯度和贴壁活性；细胞悬液的体外短期培养过程中小牛血清和珠母贝组织提取物对于细胞在体外的生长和在珠核表面的贴附具有促进作用．     

Analysis and implementation of cross sync period underwater acoustical positioning techniques for underwater targets

I.IlltroductionWhenanactiveunderwateracousticalpositioningsystemissearchingforanunderwatertarget,itisnecessaryforittocompleteatransmittingandreceivingcycIewithineachworkingperiodinordertofindoutthelocationofthetargetcorrectly.Forexample,whenanunder-wateracoustica1synchronouspositioningsystemistrackinganunderwatertargetwithagivensynchr0nizingperiod,thepropagati0ntimeofthepositioningsignaltravellingfr0mthetaJrgettothearrayofthesystemshouldbelessthanthesynchronizingperiod0therwisetargetdis-tance…     

Enantioselective Addition of Diethylzinc to Aldehydes Catalyzed by N-Sulfonylated Amino Alcohols

Asymmetric C-C bond forming reactions are of prime importance in modem synthetic organic chemistry. The use of chiral amino alcohol ligands is widespread in this area.[1] Herein, we describe the synthesis of N-sulfonylated amino alcohols 1～4 and enantioselective addition of diethylzinc to aldehydes was carried out employing titanium(Ⅳ) complexes 1～4.