手性芳香胺的酶法拆分

以芳香酮为原料合成了相应的芳香胺。首次以乙酸异丙烯酯作为酰基供体,在甲苯介质中经Novozym435酶催化对芳香胺进行拆分,得到了较高转化率和e.e.值的手性芳香胺(S-1和R-2),其中S-3-氯-苯丙胺(S-1 e)和R-3-氯-乙酰苯丙胺(R-2 e)为新手性化合物。     

La2CaB10O19晶体高效紫外激光输出研究

La2CaB10O19(LCB)为可通过Nd∶YAG激光三倍频产生355 nm紫外激光的非线性光学晶体,其光学性能可与商用化的LiB 3O 5(LBO)晶体媲美,但抗潮解特性优势明显。本文对用LCB晶体实现355 nm紫外激光输出的三倍频产生过程进行了优化设计,利用走离补偿方法来提高激光输出转换效率。通过在光路中加入沿θ=45°方向切割、厚度为1.2 mm的方解石晶体走离补偿片,在脉冲宽度为60 ns、重复频率10 kHz的激光参数下实现355 nm输出功率由12 W提升至20 W;在脉冲宽度为25 ps、重复频率为10 Hz的激光参数下355 nm转换效率由28.3%提升至35.2%。     

A CLASS OF TWO-STEP CONTINUITY RUNGE-KUTTA METHODS FOR SOLVING SINGULAR DELAY DIFFERENTIAL EQUATIONS AND ITS STABILITY ANALYSIS

In this paper, a class of two-step continuity Runge-Kutta（TSCRK） methods for solving singular delay differential equations（DDEs） is presented. Analysis of numerical stability of this methods is given. We consider the two distinct cases： （i）τ≥ h, （ii）τ 〈 h, where the delay τ and step size h of the two-step continuity Runge-Kutta methods are both constant. The absolute stability regions of some methods are plotted and numerical examples show the efficiency of the method.     

土壤中64种痕量半挥发性有机污染物的分析方法研究

利用超声提取技术将土壤中的半挥发性有机污染物(SVOC)提取出来, 经旋转蒸发浓缩至一定体积后, 用ODSC18柱净化, 再用氮吹浓缩后, 取1.0 μL注入气相色谱中, 用DB-5 ms柱分离, 用气相色谱质谱仪(GC-MS)进行定性定量分析. 本方法研究土壤中64种半挥发性有机污染物, 其中包括苯系物、苯酚类、苯胺类、硝基芳香烃类、氯代芳烃类、多环芳烃类和酞酸酯类等物质的提取、净化方法以及回收率、精密度和检测限的测定. 该方法回收率为52.5%～105%.     

Purification and in vitro Activity of an Antimicrobial Peptide from Skin of Rana Temporaria Chensinensis, David

In this study,an antimicrobial component(RTCI)was purified from the skin of Rana temporaria chensinensis,David.Antimicrobial activities of RTCI against clinical multi-drug resistant bacterial strains,including Escherichia coli,Pseudomonas aeruginosa,Staphylococcus aureaus,Klebsiella oxytoca,Klebsiella pneumoniae,Enterococcus faecalis,and Proteus mirabilis were measured in vitro by means of minimal inhibitory concentration and time-kill studies.The results indicate that RTCI could inhibit the growth of these bacteria at a proper concentration and suggest that RTCI shows a better antimicrobial activity to Gram-negative bacterial strains than to Gram-positive bacterial strains.     

水杨醛牛磺酸Schiff碱镝(Ⅲ)配合物的合成表征及热分解动力学研究(英文)

合成了水杨醛牛磺酸Schiff碱与镝(Ⅲ)的配合物,并通过元素分析、红外光谱、X射线粉末衍射及摩尔电导等对其结构进行了表征.在非等温条件下,采用Achar微分法和Coats-Redfern积分法拟合出配合物的热分解动力学方程.     

异双希夫碱配合物的合成与表征

邻苯二胺与5-氯-2-羟基二苯酮、2-羟基-1-萘醛作用合成了一种异双四齿希夫碱配体C30H21N2O2Cl(H2L)。在无水体系中该配体与金属醋酸盐作用合成了5种固体配合物[ML]·nH2O(M=Cu(Ⅱ),Zn(Ⅱ),Mn(Ⅱ),Co(Ⅱ),Ni(Ⅱ);n=0-1)。通过元素分析、IR、UV、TG-DTG及摩尔电导分析等手段对合成的配合物进行了表征。     

正己烷萃取-顶空气相色谱法测定乳胶漆中苯系物含量

应用顶空气相色谱法测定了乳胶漆中7种苯系物,即苯、甲苯、乙苯、对二甲苯、间二甲苯、邻二甲苯及苯乙烯.作为对常规的顶空法的改进,乳胶漆中的上述7种化合物预先在顶空瓶中用n-已烷萃取,以提高方法的回收率.取1 mL气体供气相色谱分析,用HP-INNOWAX极性柱作为分离柱,并采用氢火焰离子化检测器.按保留时间值作定性分析,定量分析则采用外标法.文中给出7种化合物的线性回归方程,其相关系数在0.9989～0.9999之间,求得7种化合物的检出限(S/N=3)为0.05 ng或0.1 μg·kg-1(对0.5g试样).用此方法分析了两件乳胶漆样品,根据测得结果,算得其相对标准(n=5)值均小于5%;进行了回收试验,回收率结果苯为90%～105%,甲苯为88%～102%,乙苯为85%～102%,二甲苯为80%～98%及苯乙烯为85%～102%.     

Component Analysis and Free Radicals Scavenging Activity of Physalis alkekengi L.Polysaccharide

A crude polysaccharide was extracted from Physalis alkekengi L. fruit. HPLC was used for the component analysis of the polysaccharide. The results indicate that Physalis alkekengi L. polysaccharide（PAP） was composed of rhamnose, xylose, arabinose, galactose, and glucose. Free radicals scavenging activity of PAP was studied through 3 free radicals scavenging tests. PAP exhibited high scavenging effects on OH and DPPH radicals, and both the scavenging rates were about 80%. The scavenging rate of O2^- radical was about 22%.     

荧光法测定硫酸软骨素含量的新方法

在pH=5.0的乙酸-乙酸钠缓冲溶液中,结晶紫在232.0 nm光的激发下,于467.0 nm处有一个荧光峰,其与硫酸软骨素(Chs)反应生成的缔合物在467.0 nm处荧光强度增强,且荧光强度差值与Chs浓度在0.002～1.7μg/mL范围内呈线性关系,相关系数(R)达到0.9997,回收率在99.73%～100.51%.该方法快速、灵敏和准确,可用于硫酸软骨素定量检测.