黑腔靶中超热电子特性研究

近几年来,在“神光”装置上进行了1.053μm激光与平面靶及一系列柱形黑腔靶相互作用实验。用一台多道滤波—荧光X光能谱仪(FFS)测得各种靶发射的超热X射线谱,由谱推导超热电子温度T_h和超热电子总能量E_h当照射靶单束激光能量E_(tar)为400～670J、脉宽τ=650～1150ps时,发现黑腔内明显存在两群服从Maxwell分布高能电子(T_h=35～45keV;T_(hh)=150～350kev),而且E_(he)占E_(tar)的份额为10％～12％。实验还表明:腔内的E_(he)与非线性过程特征量(SRS)有较好的线性关系,因此推断出腔内超热电子产生的主要机制是受激Raman散射。在相同照射条件下,黑腔靶产生的超热电子比平面靶严重。     

Temperature dissipation measurements in a fully developed turbulent channel flow

All three derivatives of the temperature fluctuation in a fully developed turbulent channel flow have been measured using a pair of parallel cold wires with fixed separations in either the x (streamwise), y (normal to the wall) or z (spanwise) direction. At several locations, measurements were also made, each for a range of y separations between the wires. These latter measurements were important for establishing a suitable method of correcting the data for the effect of wire separation, thus allowing the fixed separation data to be corrected. In the near-wall region, the corrected temperature dissipation is in good agreement with results from direct numerical simulations. The time scale ratio deduced from measurements and simulations agrees well with the theoretical wall value.     

Homomorphisms to oriented cycles

We discuss the existence of homomorphisms to oriented cycles and give, for a special class of cyclesC, a characterization of those digraphs that admit, a homomorphism toC. Our result can be used to prove the multiplicativity of a certain class of oriented cycles, (and thus complete the characterization of multiplicative oriented cycles), as well as to prove the membership of the corresponding decision problem in the classNPcoNP. We also mention a conjecture on the existence of homomorphisms to arbitrary oriented cycles.     

Construction of representation-finite selfinjective artin algebras of classB n andC n

In this paper, we discuss the representation-finite selfinjective artin algebras of classB _n andC _n and obtain the following main results: For any fieldk, let Λ be a representation-finite selfinjective artin algebras of classB _n orC _n overk.

含吲哚核端基多甲川菁染料的合成及性能

我们曾合成了具有桥环的硫三碳菁及多甲川苯乙烯菁,并测定了光学性能。本文报道吲哚环为端基的桥链三碳菁和四甲川苯乙烯菁的合成及在有机溶剂中电子吸收光谱及溶解性能的测定。所用仪器同前,7种多甲川菁染料的合成反应如下:     

SYNTHESIS OF SODALITE BY DRY POWDER METHOD

用新颖的干粉方法合成系列沸石的研究已从五元环沸石延伸到具有四元环和六元环的方钠石。本研究运用干粉方法在Ｎａ２Ｏ－ＳｉＯ２－Ａｌ２Ｏ３混合物中分别以乙醇胺和乙二胺－氟化物为模板，合成出了方钠石。有机模板剂以吸附态模板方式进入体系。用ＸＲＤ数据、扫描电镜图及红外光谱测试结果对实验产品做了表征。结果表明，干粉体系制备的方钠石的晶胞参数小于水热体系和非水体系合成的方钠石的相应值。而以乙醇胺为模板制备的方钠石与以乙二胺－氟化物为模板的样品比较，后者具有较快的晶化速度、较小的晶胞体积和晶粒     

Carbon Nanotubes Grown on Sepiolite as Catalyst Carrier

Multi-walled carbon nanotubes were synthesized by the catalytic decomposition of acetylene at 750℃ over sepiolite powder,which was treated with aqueous cobalt nitrate. It is expected that the composite with high specific area will have high capacity of hydrogen storage.