Lifetimes of Excited Levels in ^131Ce

The fusion-evaporation reaction ^116Sn (^19F, p3n)^131 Ce at projectile energy of 95 MeV is used to populate high spin states in ^131Ce. The de-exciting γ-rays are detected in γ-γ coincidence measurement with Compton-suppressed BGO-HPGe detectors. Level lifetimes of ^131 Ce were determined by using the Doppler shift attenuation method.The experimental results indicate that collectivity of ^131 Ce is reduced relative to that of ^130Ce and it follows that deformation decreases with increase of the neutron number on the basis of systematic comparison of transition quadrupole moments for the light cerium isotopes.     

水热处理的HZS M-5催化剂择形催化合成4 ,4′-二甲基联苯(英文)

Theshape selectivealkylationofpolycyclichy drocarbonsisusedtosynthesizesymmetricintermedi atessuchas 4 ,4′ dialkylbiphenyl (4 ,4′ DABP)and2 ,6 dialkylnaphthalene (2 ,6 DAN)whichareimpor tantprecursorsofadvancedpolymermaterials[1] .Thealkylationtoprepare4 ,4′ DABPcanbecarriedoutusingeitheralarge grouplikeisopropylorasmallgroupsuchasethylormethyl.However ,itisdiffi culttoselectivelyobtain 4 ,4′ dimethylbiphenyl(4 ,4′ DMBP)throughthemethylationofbiphenyl(BP )anditsderivatives[2 ,3] .…     

高密度聚乙烯（HDPE）在静高压下的强度研究

 高密度聚乙烯（HDPE）在1~2 GPa的静高压下发生熔体结晶。用压缩的方法对经过高压处理后的样品进行了杨氏模量的测量。测量结果表明：样品的杨氏模量随压力和结晶度的增加而增大，最大值达到1.46 GPa。伸直链晶体的形成是杨氏模量增加的重要因素。     

THE RELATIONSHIP BETWEEN ENVIRONMENT CHANGE AND SE MONSOON STRENGTH, DAIHAI LAKE, INNER MONGOLIA

Daihai Lake, located in NW margin of SE monsoon region, belongs to the sensitive area for climatic fluctuation. The analysis of continuous sedimentary column with an age of 100 ka indicates that there exists the different quasiperiodicity in time scales for monsoon shift. The climatic fluctuation in the Daihai Basin shows all along the alternation of cold and dry with a warm and wet climatic pattern, suggesting that the strength and drift of SE monsoon play a controllable role in the climatic change.     

机械合金化Cu＿（1－x）Sn＿x系的穆斯堡尔研究

利用机械合金化方法获得了几种铜－锡合金，特别是熔融法不易获得的，Ｘ射线衍射结果显示球磨使各样品纳米化，并形成包含确定合金相的固溶体，穆斯堡尔谱表明，各固溶体中除包含合金相外，还存在富锡相及富铜相，提出在机械合金化过程中，首先铜和锡纳米化，然后两种原子相互扩散形成包含合金相、富α－锡相和富ｆｃｃ铜相的固溶体。     

氖等电子序列2p^5nl（l=s,d）系列的高激发态结构

本文用本征通道量子亏损理论方法（ＥＱＤＴ方法）计算了氖等电子序列２ｐ＾５ｎｌ（ｌ＝ｓ，ｄ）系列的高激发态结构。得到基本结构参量（ＥＱＤＴ参量）随净电荷数Ｚｃ增大的变化规律，并从静电相互作用下自旋－轨道相互作用之间的竞争角度给出确切的物理解释。以ＮｅＩ为实例，给出其高激发态结构的具体数值结果。     

系列柱形薄壁腔靶制备工艺研究

为了从实验上深入研究超热电子产生规律，从而减少或抑制超热电子对惯性约束聚变（ＩＣＦ）的危害，我们制备了一系列薄壁腔靶，以供实验研究。本文详细地描述了柱形薄壁腔靶的制备工艺。利用ＮＧ－１０４型精密单向纵切车床，采用金刚石刀具车削，提高心轴质量，表表粗糙度可达０．１μｍ。采用电镀和磁控溅射二种方法镀膜，为了使腔靶壁厚均匀，在镀膜时，必须使心轴匀速旋转。利用磁控溅射在腔靶外表面再涂上１μｍ左右厚的二氧化硅，以提高超薄壁腔靶的强度和自立能力。在腐蚀心轴时，必须仔细控制酸的浓度，防止在腐蚀时因产生气泡太多，太快而使腔靶破裂。用Ｘ射线照相法和扫描电子显微镜测量腔靶的几何参数。制备系列柱形薄壁腔靶达到指标为：壁厚范围２～３０μｍ，壁厚均匀性小于１０％，表面粗糙度０．２～０．３μｍ。最后介绍了在“神光Ⅰ”上打靶结果。结果表明，实验值与理论值符合较好。