Size-controllable carbon spheres doped Ni (II) for enhancing the catalytic oxidation of methanol

Ni(II)/CSs were prepared using a simple two-step hydrothermal method. The morphology and composition of the catalysts were studied with scanning electron microscope, transmission electron microscope, and X-ray diffraction. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy showed that the surface of the prepared carbon spheres was rich in hydroxyl groups, which was beneficial to remove CO intermediates, and therefore, improving the catalytic efficiency and the antipoisoning ability of the catalysts. The results of cyclic voltammetry and chronoamperometry showed that the electrocatalytic activity and stability of Ni(II)/CSs were higher than that of unloaded NiAc under alkaline environment. When the nickel content was 5 wt.%, the peak oxidation current density of methanol on Ni(II)/CSs electrocatalyst reached the maximum of 34.54 mA/cm², which was about 1.8 times that of unloaded NiAc. These results indicate that Ni(II)/CSs has potential applications in the electrocatalytic oxidation of methanol.     

高海拔大马士革玫瑰的黄酮类化学成分

为研究高海拔种植大马士革玫瑰的化学成分,采用95%乙醇为溶剂进行连续回流提取,并采用硅胶、聚酰胺、C18及Sephadex LH-20凝胶等材料行分离纯化,最终得到了9个黄酮醇类化合物（1, 3, 5～11）和两个黄酮类化合物（2和4）,其结构经¹H NMR和¹³C NMR表征并结合理化方法鉴定为：5,7-二羟基-3,6,4'-二甲氧基黄酮醇（1）、 5,7-二羟基-6,4'-二甲氧基黄酮（2）、 5,7,4'-三羟基-3,6-甲氧基黄酮醇（3）、 5,7-二羟基-6,8,4'-三甲氧基黄酮（4）、 5,4'-二羟基-3,6,7-二甲氧基黄酮醇（5）、 5,7-二羟基-3,6,8,4'-三甲氧基黄酮醇（6）、 8-甲氧基山奈酚（7）、山奈酚（8）、槲皮素（9）、槲皮素 3-O-a-L-阿拉伯呋喃糖苷（10）、银锻苷（11）,其中化合物1～5为首次从蔷薇属植物中分离得到,化合物1～7、 10、 11为首次从大马士革玫瑰中分离得到。      

A power penalty approach to a mixed quasilinear elliptic complementarity problem

In this paper, a power penalty approximation method is proposed for solving a mixed quasilinear elliptic complementarity problem. The mixed complementarity problem is first reformulated as a double obstacle quasilinear elliptic variational inequality problem. A nonlinear elliptic partial differential equation is then defined to approximate the resulting variational inequality by using a power penalty approach. The existence and uniqueness of the solution to the partial differential penalty equation are proved. It is shown that, under some mild assumptions, the sequence of solutions to the penalty equations converges to the unique solution of the variational inequality problem as the penalty parameter tends to infinity. The error estimates of the convergence of this penalty approach are also derived. At last, numerical experimental results are presented to show that the power penalty approximation method is efficient and robust.

     

Fe(Ⅳ)的合成及其稳定性研究

通过两种方法合成出Fe(Ⅳ)溶液,研究了Fe(Ⅳ)溶液的反应性、稳定性以及添加其他离子对Fe(Ⅳ)在水溶液中的稳定性的影响,并对Fe(Ⅵ)的反应历程进行了探讨。Fe(Ⅳ)离子的氧化性较Fe(Ⅵ)离子弱,可以氧化苯甲醇,而难以氧化间二甲苯;在Fe(Ⅳ)溶液中加入磷酸钠使其稳定性下降,而加入醋酸钠可显著提高Fe(Ⅳ)在溶液中的稳定性;Fe(Ⅳ)在溶液中的浓度越高越不稳定;随着碱浓度的增加Fe(Ⅳ)在溶液中的稳定性增强且在碱水溶液中Fe(Ⅳ)比Fe(Ⅵ)更稳定。     

LC with Novel Electrochemical Detection for Analysis of Monoamine Neurotransmitters in Rat Brain After Administration of (R)-Salsolinol and (R)-N-Methylsalsolinol

A novel electrochemical detector with an acetylcholine film has been developed for HPLC. The chemically modified electrode is an efficient electrocatalyst of (R)-salsolinol ((R)-Sal), (R)-N-methylsalsolinol ((R)-NMSal), and monoamine neurotransmitters, enabling highly sensitive detection. The electrode is also stable and long-lived. Combined with microdialysis sampling, HPLC with the novel detector enabled successful study of changes in the concentrations of monoamine neurotransmitters in rat brain after the injection of (R)-salsolinol and (R)-N-methylsalsolinol.     

Existence of Pareto Solutions for Vector Polynomial Optimization Problems with Constraints

Journal of Optimization Theory and Applications - This paper deals with a vector polynomial optimization problem over a basic closed semi-algebraic set. By invoking some powerful tools from real...     

粉末活性炭基复合材料制备及净化含油污水的性能和机制

针对粉末活性炭对亲水小分子有机物吸附效率低和固液分离速度慢的问题, 本研究以粉末活性炭(PAC)、腐植酸盐(HS)、聚合氯化铝(PACl)为原料, 通过融合法成功制备了粉末活性炭基复合材料PACMC (powdered activated carbon matrix composites), 将其作为含油污水的净化吸附剂. 扫描电子显微镜-X射线能量色散谱仪(SEM-EDS)和傅里叶红外光谱(FT-IR)等表征分析确认了PACMC的微观形貌和化学组成, 证实了PAC、HS和PACl是通过化学反应生成了PACMC. PACMC具有层状多孔结构和活性官能团, 有利于含油污水分子的传输扩散和化学吸附. 通过静态吸附实验研究了PACl、PAC和PACMC对含油污水中有机物的吸附性能, 结果表明: PACMC对含油污水中有机污染物的吸附能力是PAC和PACl的2~3倍(q_e=23.04 mg•g^‒1, C₀=300 mg•L^‒1); 当吸附时间达到120 min 时, PACMC上的活性位点与含油污水中有机污染物的结合已基本达到饱和(q_e=23.04 mg•g^‒1, C₀=300 mg•L^‒1). 溶液pH值对PACMC吸附去除含油污水中有机物的影响显著, pH=3时, 吸附效果最好(q_e=27.6 mg•g^‒1, C₀=300 mg•L^‒1); 伪二级动力学方程能很好地描述含油污水中有机物在PACMC上的吸附行为, 动力学拟合结果表明其吸附过程分多步进行, 化学吸附和内扩散均具有重要作用. 等温吸附数据符合Dubinin-Radushkevich模型, 证明其吸附机理为化学吸附. 因此, PACMC吸附含油污水的机理包括化学结合/螯合作用、疏水力作用和静电吸附作用.     

高铁酸盐的电化学合成及对活性污泥的处理进展

活性污泥(WAS)产量的不断增加已经成为污水厂普遍存在的难题。高铁酸盐具有氧化、消毒、絮凝、吸附等作用,在污泥处理中具有良好的应用前景。同时,高铁酸盐在常温下具有不稳定性,极易分解,需要在线生产的技术。本文从高铁酸盐的性质出发,综述了高铁酸盐的电化学合成方法及其影响因素,并对其在线生产高铁酸盐的应用进展进行介绍;总结了高铁酸盐对于活性污泥处理中的污泥脱水、最小化和厌氧发酵等三个方面的处理机理和影响。最后,提出了对于未来发展方向的认识,以期提高处理效率、节约成本。     

A dual enzymatic-biosensor for simultaneous determination of glucose and cholesterol in serum and peritoneal macrophages of diabetic mice: evaluation of the diabetes-accelerated atherosclerosis risk

In this paper, a novel dual enzymatic-biosensor is described for simultaneous determination of glucose and cholesterol in serum and peritoneal macrophages (PMs) of diabetic mice to evaluate the risk of diabetes-accelerated atherosclerosis. The biosensor was constructed by a three-step method. First, a poly-thionine (PTH) film was assembled on the surface of glassy carbon electrode by cyclic voltammetric electropolymerization of thionine, which serves as an electron transfer mediator (ETM). Second, gold nanoparticles (GNPs) were covered on the surface of PTH facilitating the electron transfer between glucose oxidase (GOx), cholesterol oxidase (ChOx) and electrode. Finally, the enzymes, GOx, cholesterol esterase (ChE), and ChOx, were covalently attached to the PTH layer through a chitosan (CH) linker. The PTH coupled with GNPs provides good selectivity, high sensitivity and little crosstalk for the dual enzymatic-biosensor. The developed biosensor had good electrocatalytic activity toward the oxidations of glucose and cholesterol, exhibiting a linear range from 0.008 mM to 6.0 mM for glucose with a detection limit of 2.0 μM, and a linear range from 0.002 mM to 1.0 mM for cholesterol with a detection limit of 0.6 μM. The results of the diabetic mice demonstrated that the cholesterol level did not change obviously with the increase of glucose level in serum, while the cholesterol level was induced with the increase of the glucose level in PMs. Previous studies have shown that the large accumulation of cholesterol in macrophage could lead to macrophage foam cell formation, which is the hallmark of early atherosclerosis. This study provides useful further evidences for the development of diabetes-accelerated atherosclerosis.     

Cr,Nd:GGG激光陶瓷原料的制备及性能研究

以金属硝酸盐作为原料,甘氨酸为燃烧剂,采用燃烧法制备了Cr,Nd:GGG激光陶瓷原料,并采用XRD,FT-IR,SEM,荧光光谱测试手段对前驱粉体进行了形貌和结构的表征。XRD测试结果表明,经900℃煅烧能形成较好的Cr,Nd:GGG相;FT-IR测试发现在655,614,571cm-1出现了比较尖锐的吸收峰,这是由于形成了GGG相,这和XRD测试结果一致;SEM照片显示Cr,Nd:GGG前驱体在900℃煅烧3 h得到粉体的粒子呈圆球形及类球形,分布较为均匀,直径为49.5 nm;荧光测试结果表明,Cr,Nd:GGG样品的最强荧光发射峰位于1063 nm左右,是Nd3+的4F3/2→4I11/2能级跃迁导致的荧光发射,并且相比于单掺Nd3+样品的荧光发射,双掺Cr3+,Nd3+(少量Cr3+)样品荧光强度增强,这个现象说明Cr3+-Nd3+之间存在能量传递。