紫外光诱导下的固体胆红素自由基性质的ESR研究

利用电子自旋共振方法对固体胆红素及其自由基在紫外照射下的变化进行了研究,发现在紫外光下仅引起胆红素超氧自由基及半醌自由基浓度的增加,而没有新的自由基形式生成,指出Foote提出的光氧化机理假说的中间体自由基即是由上述两种自由基构成,并通过电子计算机对ESR谱的摸拟,提出了紫外辐照下的胆红素自由基形成机理,推测胆红素光化学反应的途径及产物与这两种自由基浓度及在不同环境下的反应活性有关.     

烧伤病人血浆和痂下组织中头孢噻甲羧肟的高效液相色谱测定及其药代动力学研究

烧伤病人血浆和痂下组织中头孢噻甲羧肟的高效液相色谱测定及其药代动力学研究尤忠义，雷政宏，宗光全（第三军医大学烧伤研究所重庆６３００３８）１前言感染是烧伤病人的重要死亡原因之一￣［１］．而创面则是烧伤感染的重要来源￣［２］，抗生素是防治烧伤感染的常用药...     

辣椒碱新同系物的合成、表征及辣构关系的初步探讨

合成了两种辣椒碱同系物的新成员:反-N-(4-羟基-3-甲氧基苄基)-8-甲基-4-壬烯酰胺和N-(4-羟基-3-甲氧基苄基)-3,7-二甲基-6-辛烯酰胺,并用元素分析,FT-IR,1H NMR,13C NMR等方法对其结构进行了表征,还用斯科维尔感官评定的方法对其辣度进行了测定,分别为1.2×107和3.0×106SHU.并将它们的结构和辣度与辣椒碱、降辣椒碱和高辣椒碱进行了对比,总结出影响辣椒碱同系物辣度的结构因子为脂酰基双键的位置、脂酰基主链的长度及支链.     

双层钨丝阵的软X射线辐射参数

在俄罗斯新能源研究所的Angara-5-1装置上对双层钨丝阵的辐射参数进行了实验研究,将不同结构的双层钨丝阵的实验结果及双层钨丝阵与单层钨丝阵的实验结果进行了比较.根据理论模拟提出的4种双层丝阵内爆动力学模式对3次中俄联合实验双层丝阵辐射功率结果进行了分析.双层丝阵的外层与内层同步内爆后,内层相对均匀等离子的分布将有效...     

Effect of Substitution of Cobalt for Iron in Sr4Fe6O13-δon the Catalytic Activity for Methane Combustion

A series of mixed oxides Sr₄Fe_6?xCo_xO_13?δ (x=0, 1, 2, 3, or 4) were prepared by sol‐gel method and used for catalytic combustion of methane. The structural properties of oxides were characterized by XRD, TGA, and XPS. The layered intergrowth perovskite‐like oxide Sr₄Fe₅CoO_13?δ exhibits the highest catalytic activity for methane combustion under the experimental conditions. The enhanced catalytic activity of Sr₄Fe₅CoO_13?δ for methane combustion could be attributed to the increased amount of oxygen vacancy caused by the partial substitution of cobalt for iron in the Sr₄Fe₆O₁₃, which was confirmed by TGA and XPS.     

Nano-scaled top-down of bismuth chalcogenides based on electrochemical lithium intercalation

A two-step method has been used to fabricate nano-particles of layer-structured bismuth chalcogenide compounds, including Bi₂Te₃, Bi₂Se₃, and Bi₂Se_0.3Te_2.7, through a nano-scaled top-down route. In the first step, lithium (Li) atoms are intercalated between the van der Waals bonded quintuple layers of bismuth chalcogenide compounds by controllable electrochemical process inside self-designed lithium ion batteries. And in the second step, the Li intercalated bismuth chalcogenides are subsequently exposed to ethanol, in which process the intercalated Li atoms would explode like atom-scaled bombs to exfoliate original microscaled powder into nano-scaled particles with size around 10 nm. The influence of lithium intercalation speed and amount to three types of bismuth chalcogenide compounds are compared and the optimized intercalation conditions are explored. As to maintain the phase purity of the final nano-particle product, the intercalation lithium amount should be well controlled in Se contained bismuth chalcogenide compounds. Besides, compared with binary bismuth chalcogenide compound, lower lithium intercalation speed should be applied in ternary bismuth chalcogenide compound.     

铝丝阵等离子体K壳层辐射区域测量

采用球面云母晶体,在特定的几何布局下，通过选择适当的设计参数，在1.3 MA脉冲功率装置上获得了Ly线表征的Z箍缩铝丝阵等离子体K壳层辐射时间积分2维分布。与通常采用的带滤片卡域的时间积分针孔成像相比，避免了由于无法将测量能段准确设定在K壳层辐射谱线所在能区，而造成测量结果偏离真实的K壳层辐射分布的缺点，为模拟计算Z箍缩等离子体辐射输运程序提供了更为精确的校验参数。     

Sinterization and hydration of synthesized cement clinker doped with sulfates

This paper aims to evaluate the influence of three kinds of sulfates from the green production of cement on its sintering and hydration. The properties of clinker and hydration were monitored by thermogravimetric and differential thermal analysis (TG–DTA), X-ray diffraction, X-ray fluorescence and isothermal conduction calorimeter. Results indicate that gypsum lowers the decomposition temperature of CaCO₃ and all these Sulfates will enhance the solid-phase reaction but increase melting temperature. Sulfates reduce the content of C₃S, but K₂SO₄ and 2CaSO₄·K₂SO₄ is conducive to the formation of β-C₂S. The hydration induction period is shortened by the sulfates. K₂SO₄ and 2CaSO₄·K₂SO₄ improve the early hydration of clinker, but gypsum may lightly reduce the hydration reactivity of clinker in acceleration period. 2CaSO₄·K₂SO and K₂SO can significantly accelerate the compressive strength development of cement clinker before 3 d; by contrast, gypsum is detrimental for that. The precipitation of hydration products (CH and C–S–H) in clinker with sulfates is more than that of clinker without sulfates at 9 h. K₂SO₄ can accelerate the hydration of clinker without forming ettringite.

     

腈水解酶在医药中间体生物催化研究中的最新进展

腈水解酶是生物催化领域中的一种重要催化剂,可用于羧酸的生物合成,反应过程具有条件温和、催化效率高、选择性突出、工艺绿色环保等特点,在医药中间体的制备中具有重要应用,符合原子经济性和绿色化学的发展方向。相关酶种的挖掘及改造已逐步成为新的研究热点,许多腈水解酶催化剂已被开发应用于医药中间体的合成。随着现代分子生物学技术的进步以及生物催化进入第三次发展浪潮,利用基因工程手段构建的基因工程菌或纯化酶作为催化剂已变得较为普遍,提高催化剂的催化潜力、改善其催化特性以最大程度的体现腈水解酶合成反应的独特优势,将为腈水解酶应用于更多医药中间体的合成奠定基础。本文综述了用于医药中间体合成的腈水解酶的应用与发展现状,并探讨了该领域研究所面临的前所未有的机遇与挑战。     

Application of minimum projection uniformity criterion in complementary designs for q-level factorials

We study the complementary design problem, which is to express the uniformity pattern of a q-level design in terms of that of its complementary design. Here, a pair of complementary designs form a design in which all the Hamming distances of any two distinct runs are the same, and the uniformity pattern proposed by H. Qin, Z. Wang, and K. Chatterjee [J. Statist. Plann. Inference, 2012, 142: 1170–1177] comes from discrete discrepancy for q-level designs. Based on relationships of the uniformity pattern between a pair of complementary designs, we propose a minimum projection uniformity rule to assess and compare q-level factorials.