稠油常压渣油悬浮床加氢残渣焦化的可行性研究

在小型焦化装置上 ,研究了克拉玛依炼油厂稠油常压渣油加氢残渣的焦化性能和焦化产物的分布规律 ,同时分析了将其作为稠油减渣焦化的调和进料时对焦化产物分布的影响。结果表明 ,加氢残渣焦化液体收率只有5 3%～ 5 9% ,焦炭收率高达 2 7%～ 34% ,液体产物的氮含量较高 ,焦炭中的硫、氮含量和灰分都很高 ,焦炭中富集了焦化原料中 39%～ 5 0 %的硫和 81%～ 85 %的氮 ;加氢残渣不适于单独作为焦化的进料 ;稠油减渣中调入 10 %加氢残渣生产的焦炭仍能满足 3号B类石油焦的要求 ,且产物中的汽油、柴油馏分收率变化不大 ,产物中的硫、氮分布与稠油减渣焦化产物中的硫、氮分布相差也不大。     

横截面呈周期性变化边界的轴类零件受扭应力场的解析研究

弹性理论处理横截面呈周期性变化边界的轴类零件时，往往受这类零件边界条件的限制，而影响其工程实践的推广应用．本文提出一种方法，其实质是：采用富里埃级数来逼近横截面呈周期性变化边界的轴类零件的边界形状；并应用复变函数论中保角映射原理，将零件复杂的边界形状映像成单位圆，从而使弹性理论可以分析和计算复杂边界轴类零件的应力场；再通过留数的求解实现保角映射的反变换．     

一个二元二次同余方程解的计数

设n是任意正整数,令Z_n是模n的剩余类环,并且Z^*_n是模n的即约剩余类环,即Z^*_n={s:1≤s≤n, gcd(s,n)=1}。通过利用同余理论与指数和的相关结果来研究集合T(a,b,c,n)={(x,y)∈(Z^*_n)²:ax²+by²+c≡0 mod n}的元素个数并给出集合T(a,b,c,n)元素个数的确切计算公式。     

QuEChERS结合UPLC-MS/MS测定菠菜中5种氨基甲酸酯类农药残留

建立了基于QuEChERS技术的超高效液相色谱-串联质谱法(UPLC-MS/MS),对菠菜中的5种氨基甲酸酯类农药残留量进行测定。样品均质后,以乙腈-水(体积比50∶50)提取后,盐析离心,乙腈层用N-丙基乙二胺净化后供UPLC-MS/MS测定。采用电喷雾离子源ESI正离子模式电离,质谱多反应监测模式对目标母离子和子离子进行扫描测定。5种氨基甲酸酯类农药在0.1~20.0μg/L的基质曲线范围内呈良好线性关系,相关系数r大于0.9991,3个水平的平均加标回收率为91.0%~101.0%,方法检出限和定量限分别为0.10~0.20μg/kg和0.25~0.50μg/kg,相对标准偏差为2.15%~5.57%。该方法具有操作简便、快速高效、回收率高、灵敏度高、重复性好等优点,可用于测定菠菜中的5种氨基甲酸酯类农药残留量。     

基于最优扩域上的椭圆曲线密码系统的基点选取

本文讨论了重模二次剩余的定义、性质，完整地设计出选取最优扩域上的椭圆曲线密码系统的基点的算法，并给出了选取成功的概率和相关数学证明．     

从实验残渣回收利用谈对学生进行绿色化学的教育

作为高师院校的化学专业，对学生进行绿色化学的教育至关重要。通过对实验室还原氧化铜残渣回收利用的研究，将绿色化学教育贯穿于其中。     

Dynorphin-degrading cysteine protease is highly specific for paired arginine residues

The cleavage of dynorphin and three analogs containing paired basic residues by several proteases was investigated. The cysteine protease of neuroblastoma cells cleaved only the bond between Arg-Arg residues. Submandibular arginylendopeptidase, however, cleaved bonds between both Arg-Arg and Arg-Lys residues, and pancreatic trypsin at the carboxyl sides of both arginine and lysine residues. This shows that the cysteine protease is highly specific for paired arginine residues.     

Rm的置换多项式与COSTAS矩阵

本文给出了多项式ｈｋ（Ｘ）＝１十ｘ十ｘ２＋…＋ｘｋ置换剩余类环Ｒｍ（Ｚ／（ｍ））的充分必要条件；证明了Ｒｍ的纯奇次置换多项式ｆ（ｘ）不能生成ｍ×ｍ（ｍ≥４）的Ｃｏｓｔａｓ矩阵．并深人讨论了迪克逊多项式ｇｋ（ｘ，ａ）和ｈｋ（ｘ）与Ｃｏｓｔａｓ矩阵的关系．     

利用啤酒废糟发酵生产菌体蛋白饲料的研究

记述了利用啤酒废糟为原料，经多种微生物发酵生产菌体蛋白饲料的工艺及过程。发酵后的饲料价廉质优，是牲畜理想的精饲料。     

Nucleotide binding domains of human CFTR: a structural classification of critical residues and disease-causing mutations.

Defective function of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) causes CF, the most frequent lethal inherited disease among the Caucasian population. The structure of this chloride ion channel includes two nucleotide-binding domains (NBDs), whose ATPase activity controls channel gating. Recently, the experimental structures of mouse and human CFTR NBD1 and our model of the human CFTR NBD1/NBD2 heterodimer have provided new insights into specific structural features of the CFTR NBD dimer. In the present work, we provide a structural classification of CF-causing mutations which may complement the existing functional classification. Our analysis also identified amino acid residues which may play a critical role in interdomain interaction and are located at the NBD1-NBD2 interface or on the surface of the dimer. In particular, a cluster of aromatic amino acids, which includes F508 and straddles the two NBDs, might be directly involved in the interaction of the NBD1/NBD2 heterodimer with the channel-forming membrane-spanning domains.Received 24 May 2005; received after revision 13 June 2005; accepted 18 June 2005