短小芽孢杆菌质粒pCJ3的衍生质粒pAl32的酶谱及抗性基因定位

从短小芽孢杆菌四环素抗性质粒pCJ3截短的衍生质粒pAL32,经用6种限制酶双酶解试验,根据琼脂糖凝胶电泳带估算各片段的分子量,作出了pAL32的6种限制酶图谱。利用已除去复制功能的金黄色葡萄球菌质粒pUB110与pAL32构建的Km~rTc~r的双抗性重组质粒pSC33为载体,在EcoRV位点克隆的λDNA片段的重组子均为Km~rTc~s。用pUB110与pAL32在PvuⅡ位点连接后的重组质粒也为Km~rTc~s。根据这些重组子四环素抗性的失活,推知pAL32上EcoRV与PvuⅡ切点均位于其四环素抗性基因上。     

方形活塞声源辐射阻抗的数值计算

利用高斯数值积分方法,推导了方形活塞辐射阻抗的三重积分表达式,计算了方形活塞声源的辐射阻抗.结果表明,方形活塞的辐射阻抗是波数和活塞边长乘积的函数,系统在高频段向外辐射的声功率比低频段大,高频段同振质量比低频段小.     

彗—木相撞辐射引力波的估算

选用一合理的模型，估算了１９９４年７月发生的彗（ＳＬ９）—木相撞辐射引力波的强度和功率．所得结果表明引力辐射强度远低于目前引力波检测装置所达到的灵敏度．计算过程与所得结果富有启发性     

Study on screening and cultivation conditions of xylanase-producing alkalophilic bacterial

Xylanisthemajorcomponentofplantcellwallsandthemostabundantpentosaninnature.Xylancontainsβ 1,4 linkedd xylosebackboneswitharabinose,4 O methyl d glucuronicacid,andaceticacidsubstituents[1 ] .Thexylan degradingen zymesincludeendoxylanase(1,4 β d xylanxylanohydrolase;EC3.2 .1.8)and β xylosidase (1,4 β d xylanxylanohydrolase;EC 3.2 .1.37) .xylanasedegradesthexylanbackboneintoxylo bioseandxylooligosaccharides,whileβ xylosidasereleasesxylosylresiduesfromthenonreducingendsofxylooligosaccha…     

Structural stability of infinite-layer CaCuCO<Subscript>2</Subscript> under high pressure

Since the discovery of high temperature supercon-ductivity by Bednorz et al. in 1986[1], many series of cu- prate superconductors have been synthesized. Critical temperature has been improved continuously. But no verdict has been given upon what mechanism causes su- perconductivity. CaCuO2 conductive layers are the parent structure of the high Tc cuprate superconductors, such as Cu-12 (n-1)n[2], Tl-12(n-1)n[3] and Hg-12(n-1)n[4,5] super- conductor families. In 1988, infinite-layer (Ca0.86S…     

巴马香猪无细胞真皮与人无细胞真皮动物移植实验效果的比较

目的:比较辐照巴马香猪无细胞真皮与辐照人无细胞真皮移植动物实验效果.方法:以机械去表皮法制备无细胞真皮与人无细胞真皮辐照(剂量30 KGy)处理后移植于W istar大鼠全厚皮肤缺损创面进行比较.结果:辐照处理的巴马香猪无细胞真皮与人无细胞真皮在大鼠创面愈合过程相似,愈合后创面收缩率差异不显著.结论:辐照处理的巴马香猪无细胞真皮与辐照处理的人无细胞真皮移植于W istar大鼠全厚皮肤缺损创面恢复效果无显著差异,可作为人无细胞真皮的替代品进一步用于烧伤治疗的研究.     

An experimental study on variation of thermal fields during the deformation of a compressive en echelon fault set

The temperature variations during deformation of a compressive en echelon fault set in a rock sample were measured by a surface measurement system with multi-point platinum resistance thermometers and an infrared thermal image system. The measurements obtained by the two systems were in agreement with each other, indicating a relationship between temporal-spatial variations of the thermal field and changes of stress and strain. At varied structural positions of the rock sample, the rising of the temperature was different, implying distinct stress distributions at these positions. In the experiment, the deformation process of the sample included three stages: elastic deformation, stick-slip, and rupture. Correspondingly, the variation process of temperature had also three stages, each of which had its own temperature rising profile. And the thermal radiation field showed a similar process. These phenomena mean that the dominant mechanisms of temperature rising in all stages of deformation are different. Experimental results provide a physical basis for the study of current fault activities by using data of satellite infrared images.     

穆斯堡尔效应的发现

介绍了穆斯堡尔的生平，回顾了穆斯堡尔发现固体中γ辐射的原子核无反冲共振吸收效应的历程，着重说明了穆斯堡尔在研究中严谨的作风，巧妙类比的思维方法以及高昂的激情在创新中发挥的重要作用．     

蜡状芽孢杆菌对番茄青枯雷尔氏菌致病性的影响

青枯雷尔氏菌（Ralstonia solanacearum）从其致病性上可分为能使植株发病的强致病力菌株和不能使植株发病的弱致病力菌株．利用蜡状芽孢杆菌（Bacillus cereus）与致病性稳定的青枯雷尔氏菌强致病力菌株进行共培养，处理后的青枯雷尔氏菌在TTC平板上表现为弱毒株的菌落特征，出现了致弱现象．经过16S rDNA基因序列测定，证明了用蜡状芽孢杆菌处理前后的菌株为青枯雷尔氏菌，并非是其它的污染菌株，通过回接番茄盆栽苗发现致弱前的青枯雷尔氏菌能有效引起番茄发生青枯病，而致弱后的菌株丧失致病力．不能引起番茄发病，