Application of thermo-electrochemistry to simultaneous leaching of sphalerite and MnO2

In order to enhance the electrogenerative leaching rate of sphalerite reasonably, the basic principle of generative process was applied to the simultaneous leaching of sphalerite in the presence of MnO₂. It was confirmed by experimental results that both mental ions and electric energy could be obtained in the simultaneous electrogenerative leaching process. The leaching cell had the open circuit potential about 1.0 V, about 2000 C of electric quantity was obtained, the optimal leaching ratio of Zn²⁺ and Mn²⁺ was 48.5, 39.6% respectively, after electrogenerative leaching for 11 h.     

三核簇合物(Et4N)2[(CO)4MoS2MoS2Mo(CO)4]和(Et4N)2[(CO)4MoS2WS2Mo(CO)4]的合成及晶体结构

合成了含Mo(0)的三核化合物(Et₄N)₂[(CO)₄Mo(μ-S)₂Mo(μ-S)₂Mo(CO)₄](Ⅰ)和(Et₄N)₂[(CO)₄Mo(μ-S)₂W(μ-S)₂Mo(CO)₄](Ⅱ),测定了(Ⅰ)的晶体结构.Ⅰ属单斜晶系,空间群P2相似文献   

Use of cotton as a sorbent for on-line precolumn enrichment of polycyclic aromatic hydrocarbons in waters prior to liquid chromatography determination

Using cotton as a solid-phase extraction sorbent of the precolumn, an on-line coupled precolumn preconcentration-liquid chromatography system with fluorescence detection was developed for the determination of PAHs in aqueous samples. Four PAHs including fluorene, phenanthrene, fluoranthene and benzo[k]fluoranthene were preconcentrated by a precolumn packed with 30 mg of absorbent cotton and then separated by C₁₈ analytical column. When 100 ml of sample was enriched, the proposed procedure provided detection limits in the range of 0.5-57 ng l⁻¹. Several water samples spiked with PAHs were analyzed with recoveries in the range of 92-119% at spiking level of 100 ng l⁻¹ for fluorene, phenanthrene and fluoranthene, and 10 ng l⁻¹ for benzo[k]fluoranthene, respectively.     

Point-splitting regularization for gauge theories: Quantum electrodynamics

As a method of regularization, point splitting has played an essential role in the recent theoretical determination of the masses of the Higgs boson and the top quark. It is the purpose of this paper to put this pointsplitting regularization on a firm basis. The result turns out to be extremely simple: replace the usual vertex factor-ieγ ^µ in quantum electrodynamics by $$ - ie(\gamma _\mu - \frac{{\not p}}{{p \cdot \delta }}\delta _\mu ),$$ wherep is the momentum of the photon line, andδ ^µ is the distance for point splitting. No additional vertices are needed.     

N，N’－双［（1－苯基－3－甲基－5－氧－4－吡唑啉基）亚苄基］乙二亚胺萃取钯的机理及钯－铂体系中钯的选择性萃取

本文首次报道了标题试剂Ｈ２Ａ对钯的萃取行为，确定了萃取物的组成，讨论了萃取机理，算出了萃取平衡常数．通过化学分析、红外及拉曼光谱、紫外光谱，研究得出了萃合物的结构，并且实现了Ｈ２Ａ从钯－铂混合溶液中选择性萃取钯．     

5－（4－乙酰氧基苯基），10，15，20－三苯基卟啉金属配合物修饰的铂支撑双层脂膜的IV性质

合成并表征了５－（４－乙酰氧基苯基），１０，１５，２０－三苯基卟啉及其金属配合物，将它们作为修饰物，制得铂支撑的双层脂膜，用循环伏安法研究了抗坏血酸的氧化还原反应，并对其机理作了探讨。     

含吡啶环系西佛碱大环配合物和氮杂大环自由配体的合成

2,6-二羟甲基吡啶(1)经活性MnO_2氧化得到2,6-二甲酰基吡啶(2)。邻硝基苯酚与N-取代的二(氯乙基)胺在DMF溶液中反应,得到N-取代的1,5-二(邻硝基苯氧基)-3-氮杂戊烷(3a～3c),再经水合肼/Raney Ni还原,获得N-取代的1,5-二(邻氨基苯氧基)-3-氮杂戊烷(4a～4c)。利用Ba~(2 )作为模板离子,(2)分别与(4a～4c)反应,合成了一类新的含吡啶环系西佛碱大环配合物Ⅰ～Ⅲ,配合物Ⅰ、Ⅲ经与NaBH_4的乙醇溶液还原解络,得到氮杂大环自由配体Ⅳ和Ⅴ。所有西佛碱大环配合物和氮杂大环自由配体均经元素分析、IR、~1H NMR、MS等证实了它们的结构和组成。     

Synthesis and characterization of 6-O-acyl-2-O-alpha-D-glucopyranosyl-L-ascorbic acids with a branched-acyl chain

We previously reported the chemical synthesis of a series of novel monoacylated vitamin C derivatives, 6-O-acyl-2-O-alpha-D-glucopyranosyl-L-ascorbic acids (6-Acyl-AA-2G) possessing a straight-acyl chain of varying length from C(4) to C(18), as effective skin antioxidants. In this paper, we describe branched type of 6-Acyl-AA-2G derivatives (6-bAcyl-AA-2G) synthesized by use of a 2-branched-chain fatty acid anhydride as an acyl donor. The stability of 6-bAcyl-AA-2G in neutral solution was much higher than that of 6-Acyl-AA-2G, while they were susceptible to enzymatic hydrolysis for exerting vitamin C effect. These branched derivatives as well as 6-Acyl-AA-2G increased the radical scavenging activity against 1, 1-diphenyl-2-picrylhydrazyl and the lipophilicity in octanol/water-partitioning systems with increasing length of their acyl group. In addition, the 6-bAcyl-AA-2G derivative with an acyl chain of C(12), 6-bDode-AA-2G had the excellent solubility to various solvents, suggesting easy handling in cosmetic use. These characteristics of 6-bAcyl-AA-2G may be available for skin care application as an effective antioxidant.     

Y2O3, La2O3, Sm2O3对氧化铝瓷烧结及力学性能的影响

研究了3种稀土氧化物对氧化铝陶瓷烧结性能和力学性能的影响.结果表明 含Y2O3,La2O3,Sm2O3的添加剂促进了氧化铝瓷的烧结,提高了氧化铝瓷的力学性能.Y2O3和Sm2O3掺量为0.50%,La2O3掺量为0.75%时氧化铝瓷在1600或1620 ℃保温2 h烧结,相对密度达98.9%以上,强度超过439 MPa,断裂韧性达5.15 MPa·m1/2以上.微观结构分析表明,Y2O3,La2O3,Sm2O3抑止氧化铝晶粒生长,细化晶粒,使晶粒尺寸较均匀形成致密化结构.