中空Ag纳米球壳的制备及性能表征

 以改性聚苯乙烯微球为模板,采用化学镀法在聚苯乙烯微球表面包覆一层银,在四氢呋喃溶液中将聚苯乙烯微球溶解,得到中空Ag纳米球壳。采用扫描电镜、透射电镜和X射线衍射仪对样品进行了表征及分析,并用紫外可见分光光度计研究了粒子的光学性质。实验结果表明：运用此法成功地制备出中空Ag纳米球壳的内径为250 nm,壁厚约为15 nm,并且成功地使纳米粒子的紫外吸收光谱由600 nm红移至900 nm左右,实现了在可见光至近红外光区调节Ag纳米结构的吸收峰。     

离子液体[BDMIM]PF_6修饰碳糊电极的制备及其电化学性能

以离子液体1,2-二甲基-3-丁基咪唑六氟磷酸盐（[BDMIM]PF6）代替传统液态石蜡为粘合剂与石墨粉相混合,制备了一种新型的离子液体修饰碳糊电极（IL/CPE）。采用扫描电子显微镜分别对其表面形貌和石蜡碳糊电极（CPE）表面形貌进行了表征。以亚铁氰化钾为电化学探针对IL/CPE的电化学行为进行了研究,并与CPE进行了比较。结果表明,[BDMIM]PF6由于具有较高的导电性,使IL/CPE比CPE具有更高的导电效率,铁氰化钾在电极上的可逆性变好,ΔEP值变小,峰电流响应增加10倍,电极过程由CPE上的吸附控制变为扩散控制,根据计时库仑法求解出铁氰化钾的扩散系数为5.52×10^-6cm2/s（25℃）。电化学交流阻抗图亦表明与不导电的液态石蜡油相比,离子液体的存在加快了电子传递。     

改良干法压裂液摩擦阻力特性实验研究

对改良的干法压裂液这种非牛顿流体的摩擦阻力特性的正确认识,关系着干法压裂技术的有效实施.为此,本文在大型高压泡沫压裂液实验回路上,考察了在模拟实际施工条件下的改良干法压裂的摩擦阻力特性.实验表明:改良后的干法压裂液摩擦阻力系数随压力、温度的升高和泡沫质量的增加而增大,随流速的增加而减小.在实验范围内,温度对摩擦阻力系数的影响不大.实验得到了改良的干法压裂液摩擦阻力系数与广义雷诺数的关联式,平均计算误差为9.19%.     

Phenolics Profiling of Carpobrotus edulis (L.) N.E.Br. and Insights into Molecular Dynamics of Their Significance in Type 2 Diabetes Therapy and Its Retinopathy Complication

Adverse effects associated with synthetic drugs in diabetes therapy has prompted the search for novel natural lead compounds with little or no side effects. Effects of phenolic compounds from Carpobrotus edulis on carbohydrate-metabolizing enzymes through in vitro and in silico methods were assessed. Based on the half-maximal inhibitory concentrations (IC₅₀), the phenolic extract of the plant had significant (p < 0.05) in vitro inhibitory effect on the specific activity of alpha-amylase (0.51 mg/mL), alpha-glucosidase (0.062 mg/mL) and aldose reductase (0.75 mg/mL), compared with the reference standards (0.55, 0.72 and 7.05 mg/mL, respectively). Molecular interactions established between the 11 phenolic compounds identifiable from the HPLC chromatogram of the extract and active site residues of the enzymes revealed higher binding affinity and more structural compactness with procyanidin (−69.834 ± 6.574 kcal/mol) and 1,3-dicaffeoxyl quinic acid (−42.630 ± 4.076 kcal/mol) as potential inhibitors of alpha-amylase and alpha-glucosidase, respectively, while isorhamnetin-3-O-rutinoside (−45.398 ± 4.568 kcal/mol) and luteolin-7-O-beta-d-glucoside (−45.102 ± 4.024 kcal/mol) for aldose reductase relative to respective reference standards. Put together, the findings are suggestive of the compounds as potential constituents of C. edulis phenolic extract responsible for the significant hypoglycemic effect in vitro; hence, they could be exploited in the development of novel therapeutic agents for type-2 diabetes and its retinopathy complication.     

Self-interstitial configuration in molybdenum studied by modified analytical embedded atom method

The stability of various atomic configurations containing a self-interstitial atom (SIA) in a model representing Mo has been investigated using the modified analytical embedded atom method (MAEAM). The lattice relaxations are treated with the molecular dynamics (MD) simulation at absolute zero of temperature. Six relatively stable self-interstitial configurations and formation energies have been described and calculated. The results indicate that the [111] dumbbell interstitial S₁₁₁ has the lowest formation energy, and in ascending order, the sequence of the configurations is predicted to be S₁₁₁, C, S₁₁₀, T, S₀₀₁ and O. From relaxed displacement field up to the fifth-NN atoms of six configurations, we know that the relaxed displacements depend not only on separation distances of the NN atoms from the defect centre but also strongly on the direction of the connected line between the NN atoms and the defect centre. The equilibrium distances between two nearest atoms in the core of the S₁₁₁, C, S₁₁₀, T, S₀₀₁ and O configurations are 0.72a, 0.72a, 0.71a, 0.72a, 0.70a and 0.70a, respectively.      

聚L-谷氨酸修饰电极的制备及对多巴胺的测定

用循环伏安法制备了聚L-谷氨酸修饰玻碳电极,研究了多巴胺在聚L-谷氨酸修饰电极上的电化学行为,建立了测定多巴胺的新方法。在pH 7.5的磷酸盐缓冲溶液中,用循环伏安法测定多巴胺的线性范围为1.0×10-4~4.0×10-8mol.L-1,检出限为5.0×10-9mol.L-1。该法用于药剂中多巴胺的测定,结果满意。     

改性壳聚糖树脂对利尿剂的吸附性能

用琥珀酸酐、苯甲酸酐、聚乙烯亚胺和 3 氯 2 羟丙基三甲基氯化铵对壳聚糖进行改性 ,分别在其氨基上引入羧基、苯环、多氨基和季胺基 ,并利用红外谱图对于改性后的壳聚糖的结构进行了分析 .应用相转移法制备了 4种改性壳聚糖的微球 ,实验研究了这 4种微球对 9种不同利尿剂的吸附性能 .结果表明 ,由于Lewis酸碱相互作用 ,引入羧基后的壳聚糖树脂对 3种碱性利尿剂的吸附量有了 15 %～ 36 %的提高 ,而引入多氨基的壳聚糖树脂对四种酸性利尿剂的吸附量分别提高了 4 8 5 %～ 2 0 9% ;由于苯环和利尿剂的憎水性基团的相互作用 ,引入苯环后的壳聚糖树脂对所有的利尿剂的吸附量都有所提高 ,其幅度为 15 %～ 6 1% ;因为季胺基团和羧基之间发生的离子交换作用 ,引入季胺基后的树脂对具有羧基的利尿剂吸附量有显著的提高 ,尤其对布美它尼的吸附量提高了 2倍以上 .     

化学发光酶免疫方法检测克伦特罗残留

建立了间接竞争化学发光酶免疫法(competitive indirect chemilumine scent enzyme immunoassy,ic-CLEIA)检测猪尿中残留克伦特罗(clenbuterol,CLB)的方法,并优化了竞争反应时间,Tween-20含量,PBS离子强度与pH4个参数。优化后的ic-CLEIA检出限可达0．01μg/L,检测范围为0．04～25．8μg/L,ED50为0．54μg/L;尿样检测的平均回收率为98％～120％,批内与批间相对标准偏差(variation of coefficent,CV)均小于10％。这些参数均优于目前广泛使用的ELISA方法,说明本CLEIA方法可替代ELISA法,用于实际尿样的检测。     

超支化聚(酰胺-酯)的端基光致变色改性研究

采用丁二酸酐、三羟甲基氨基甲烷为主要原料,先在冰水浴条件下合成AB3型单体,然后进行熔融缩聚制得超支化聚(酰胺-酯)(HBP),最后用4-(4′-二甲氨基苯基偶氮)苯甲酸对HBP的末端羟基进行功能化改性,得到了一种具有光致变色和酸碱变色性的HBP;用紫外光谱对改性超支化聚(酰胺-酯)的变色性进行了研究。结果表明：随紫外光照时间延长紫外吸收强度增加;随pH值增大紫外吸收波长向短波方向移动。     

Ito 5阶和7阶mKdV方程新的周期解

§ 1　IntroductionIn recent years,a research of direct seeking for exactly solutions of nonlinear waveequations (NL WEs) has attracted much attention because of the availability of symboliccom- putation.Many methods,such as the homogeneous balance method[1 ] ,extended tanh-function method[2 ] ,Jocobi elliptic function expansion m ethod[3] ,are developed for thepurpose.In [4 ]the cn- function method,dn- function method and cs- function method wereproposed and applied to some NL WEs.It is sh…