出钢过程钢水净化工艺优化研究

介绍了转炉在出钢过程强化钢水净化的工艺,实验结果表明:该工艺能在较短时间内降低钢水及熔渣氧化性,利用出钢过程良好的动力学条件进行脱硫,从而提高了LF精炼炉的精炼效果,显著提高了钢水纯净度.通过对工艺的优化和完善,可使部分钢种不经LF炉处理也能满足品种钢性能的要求,进而缓解LF炉作业压力,减少了LF增碳增硅的几率,提高了低碳低硅钢的成分命中率.     

无机阻燃剂Sb2O5的合成

以水合锑酸钠为原料,经酸化、分离、分散等步骤,制备胶态五氧化三锑水溶胶,对这一合成方法的工艺条件进行优化筛选,并制得平均粒径为０．０５μｍ的五氧化二锑。     

8098单片机开关磁阻电动机调速系统

开关磁阻电动机调速系统是２０世纪８０年代中期兴起的一种新型调速系统,本文介绍了开关磁阻电动机调速系统的基本原理,并设计了一种用８０９８单片机实现的开关磁阻电动机调速系统,实验证明该系统运行可靠。     

两类探测轴子实验中耦合常数间的关联

采用微扰计算方法,探讨了轴子探测实验中两类耦合常数间的关联.低阶微扰计算结果表明:轴子的电磁衰变振幅与轴子和光子相互作用的耦合常数有关,由此得到了轴子一光子相互作用的耦合常数与轴子-核子耦合常数之间的关系式.此关系式可用于两类轴子探测实验结果的之间的相互比较和转换.     

Hierarchical self-assembly of DNA into symmetric supramolecular polyhedra

DNA is renowned for its double helix structure and the base pairing that enables the recognition and highly selective binding of complementary DNA strands. These features, and the ability to create DNA strands with any desired sequence of bases, have led to the use of DNA rationally to design various nanostructures and even execute molecular computations. Of the wide range of self-assembled DNA nanostructures reported, most are one- or two-dimensional. Examples of three-dimensional DNA structures include cubes, truncated octahedra, octohedra and tetrahedra, which are all comprised of many different DNA strands with unique sequences. When aiming for large structures, the need to synthesize large numbers (hundreds) of unique DNA strands poses a challenging design problem. Here, we demonstrate a simple solution to this problem: the design of basic DNA building units in such a way that many copies of identical units assemble into larger three-dimensional structures. We test this hierarchical self-assembly concept with DNA molecules that form three-point-star motifs, or tiles. By controlling the flexibility and concentration of the tiles, the one-pot assembly yields tetrahedra, dodecahedra or buckyballs that are tens of nanometres in size and comprised of four, twenty or sixty individual tiles, respectively. We expect that our assembly strategy can be adapted to allow the fabrication of a range of relatively complex three-dimensional structures.     

A biomass burning record from the Lingtai Loess Section during the last 370 ka and implication for climate and environment

Every moment of every day somewhere on Earth a wildfire burns. Generally three conditions are needed to cause such a wildfire: fuel, ignition, and favorable cli-mate characterized by certain critical temperature, hu- midity and oxygen content, etc. Occurr…     

新疆东部草原鼠害的调查及危害类型的划分

作者于1992年和1993年夏末秋初对新疆东部哈密市、巴里坤哈萨克自治县和伊吾县的草原鼠害进行了全面的普查,共捕获鼠类20种,并根据害鼠优势种的组成和自然环境特征,划分为5个危害类型,对每一危害类型进行了详细的说明。     

快中子辐照对小麦幼苗生长以及过氧化物酶和酯酶同功酶的影响

本文研究了快中子辐照对小麦幼苗生长以及过氧化物和酯酶同功酶的影响。结果表明，随着辐照剂量的增大，小麦幼苗的苗高、鲜重和干重都明显降低；叶绿素ａ和叶绿素ｂ也出现缓慢下降趋势；然而，膜透性却逐渐升高。过氧化物酶同功酶酶谱发生了很大的变化。处理１少一条带（Ｒｆ０．１８），增加三条带（Ｒｆ０．３４、０．３７、０．３８）；处理２少一条带（Ｒｆ０．１８），出现了三条新带（Ｒｆ０．０１７、０．０３９、０．５７）；处理３少一条带（Ｒｆ０．１８），增加一条新带（Ｒｆ０．５７）。脂酶同功酶也发生了变化。     

马尾松枝桠材应压木与对应木的解剖研究

<正>本文研究了马尾松枝桠材的应压木、对应木与正常干材的解剖特征,比较了三者在生长轮宽度、晚材率、早晚材过渡形式、管胞形状,胞间隙、螺纹裂隙等方面的异同,发现它们在管胞长度、管胞直径及细胞壁厚度、细胞壁超微结构以及次生壁S_2层微纤丝角度诸方面存在差异。