Determination of wear metals in oil using energy dispersive x-ray spectrometry

Trace elements in oil can be determined by adsorption of the oil sample onto magnesium oxide followed by thermal degradation of the organic material. The resulting powder is easily pressed into a pellet suitable for x-ray spectrometric analysis. The lower limit of detection depends upon the trace impurities in the magnesium oxide and is a few μg g^?1 for most elements determined.     

多金属氧酸盐载Pd催化剂制备及其对甲酸氧化的电催化性能

多金属氧酸盐;直接甲酸燃料电池;钯;介孔分子筛     

稀土季铵盐配合物的研究(Ⅶ)──二硝酸四硫氰酸合铒酸四丁基铵的合成、表征和晶体结构

合成了一系列新型稀土季铵盐混合配体配合物,元素分析结果证明其分子式的通式为:C₅₂H₁₀₈LnN₉O₆S₁(Ln=Eu,Dy,Er.Yb,Y).研究了该系列配合物的中红外光谱;测定了它们在乙醇溶液中的摩尔电导,证明其属3:1型电解质。用四圆衍射仪测定了铒配合物的晶体结构,属正交晶系,P_nnn空间群,晶胞参数:α=1.2470(7)nm,b=1.2934(3)nm,c=2.1112(6)nm,Z=2,R=0.066.中心离子铒被来自2个硝酸根的4个氧原子和4个硫氰酸根的4个氮原子所配位,配位数为8.Er-O键长为0.2386nm;Er-N键长为0.2457nm,饵配位多面体为畸变三角十二面体。     

直接热分解法制备的碳载Pt-Sn催化剂对乙醇氧化的电催化性能

以Pt( NO3)2和SnO为前驱体采用直接热分解法制备了碳载Pt-Sn (Pt-Sn/C)催化剂.用X射线衍射(XRD)、透射电镜(TEM)和X射线光电子能谱(XPS)等技术对催化剂进行了表征,用循环伏安法和CO溶出等方法研究了催化剂对乙醇氧化的电催化性能.结果表明,Pt-Sn/C催化剂中的Pt-Sn粒子具有Pt-S...     

不同载量pt/c催化剂制备及其对甲醇氧化的电催化活性

有机溶胶法;pt/c催化剂; pt载量;甲醇     

固相反应法合成掺铝的α型氢氧化镍及其电化学性能

Ni(OH)₂ including 20% Al was synthesized by solid-state reaction. The result of XRD indicated that the sample thus prepared was α-Ni(OH)₂， and its size and crystalline form were much poorer than those of the sample prepared by solution-state reaction. TG and DTA curves showed that α-Ni(OH)₂ began to decompose at higher temperature than β-Ni(OH)₂. The electrochemical behaviors of the sample were studied by cyclic voltammetry and constant current charge-discharge experiment. It was found that the sample by solid-state reaction had more ex-cellent electrode reversibility， higher discharge potential and higher discharge capacity.     

4-(4-甲基苯氧基)苄胺的合成

甲基苯氧基苄胺;农药;4-(4-甲基苯氧基)苄胺的合成     

云南稻核心种质糙米功能成分栽培型差异及其地带性特征

采用Beckman公司DU640型紫外-可见分光光度计测定了五个稻作区16个州市的905份云南地方稻初级核心种质功能成分栽培型间差异及地带性特征,结果表明:糙米抗性淀粉(%)为0.75±0.29,籼稻(0.78±0.35)显著高于粳稻(0.74±0.24),粘稻(0.78±0.31)极显著高于糯稻(0.67±0.22),晚稻(0.77±0.35)极显著高于早中稻(0.75±0.26),红米(0.81±0.30)和紫米(0.70±0.30)极显著高于白米(0.69±0.27);稻作区依次为Ⅰ(0.83)Ⅱ(0.79)Ⅲ(0.76)Ⅴ(0.55)Ⅳ(0.50),即滇中南部(Ⅰ,Ⅱ,Ⅲ)糙米抗性淀粉含量极显著高于北部稻作区(Ⅴ,Ⅳ);滇西北的丽江和滇东北的昭通糙米抗性淀粉含量极显著低于除迪庆州外的13个州市。糙米γ-氨基丁酸含量[mg.(100 g)-1]为7.43±2.53,水稻(7.59±2.56)极显著高于陆稻(7.09±2.45),糯稻(8.55±2.88)极显著高于粘稻(7.10±2.32),晚稻(7.88±2.64)极显著高于早中稻(7.23±2.45),白米(8.38±2.66)极显著高于红米(6.63±2.14)和紫米(7.34±2.18);稻作区依次为Ⅱ(7.69)Ⅰ(7.40)Ⅳ(7.39)Ⅲ(7.33)Ⅴ(6.64),即滇南单双季籼稻区(Ⅱ)糙米γ-氨基丁酸含量明显高于滇西北高寒粳稻区;滇南的思茅、滇中的玉溪和保山糙米γ-氨基丁酸含量至少与5个州市差异显著。云南稻糙米总黄酮含量[mg.(100 g)-1]为306.98±192.75,陆稻(341.74±185.11)极显著高于水稻(290.41±193.72),粘稻(315.54±197.64)显著高于糯稻(171.68±11.76),早中稻(318.25±197.93)极显著高于晚稻(282.12±178.11),红米(379.22±197.70)和紫米(365.61±195.44)极显著高于白米(216.96±142.11),光壳稻(332.68±196.22)显著高于白壳稻(300.48±191.14);稻作区依次为Ⅲ(327.13)Ⅱ(324.23)Ⅳ(273.11)Ⅴ(270.16)Ⅰ(258.26),即滇南(Ⅱ,Ⅲ)糙米总黄酮含量极显著高于滇中;思茅糙米总黄酮含量显著高于8个州市而保山总黄酮含量则显著低于7个州市。这些既揭示了糙米抗性淀粉、γ-氨基丁酸和总黄酮、含量在水陆、沾糯、早中晚、米色间差异极显著(p0.01),而有无芒和米味间差异不大,又揭示了3种功能成分呈现明显的地带性特征。文章研究为解决人类慢性病问题以及功能稻米育种生产提供参考。     

Pt-Ru/C催化剂在甲醇电氧化过程中的组成和结构变化

本文研究了Pt-Ru/C催化剂在甲醇电催化氧化过程中组成和结构的变化。结果表明:在扫描初期,Pt-Ru催化剂的表面处于富Ru状态,Pt-Ru催化剂显示出良好的协同效应,峰电位较低,峰电流密度也较小。随着扫描圈数的增加(1~35圈),催化剂表面Ru原子逐渐溶解,Pt-Ru协同效应减弱,峰电位逐渐增大;同时,随着Ru的溶解,催化剂表面Pt原子含量的增加,催化剂对甲醇氧化的峰电流密度逐渐增大。继续增加扫描圈数(36~80圈),催化剂表面Ru原子含量趋于稳定,但Pt原子发生表面重组,粒子粒径增大,从而导致催化剂对甲醇电氧化性能下降。     

The influence of alkane spacer of bis(diphenylphosphino)alkanes on the nuclearity of silver(I): Syntheses and structures of P,P′-bridged clusters and coordination polymers involving dithiophosphates

The effect of the length of alkane spacer in diphosphines on the nuclearity of Ag(I) complexes containing dialkyl dithiophosphates (dtp) ligands has been investigated. 1,1-Bis(diphenylphosphino)methane (dppm) yielded tetranuclear [Ag₄(dppm)₂{S₂P(OEt)₂}₄] (1), [Ag₄(dppm)₂{S₂P(OⁱPr)₂}₄] (3), trinuclear [Ag₃(dppm)₃{S₂P(OEt)₂}₂](PF₆) (2), and a dinuclear [Ag₂(dppm)₂{S₂P(OⁱPr)}](PF₆) (4). The increase in spacer length from one methylene in dppm to two in 1,2-bis(diphenylphosphino)ethane (dppe) resulted in the formation of polymeric, [Ag(dppe){S₂P(OR)₂}]_∞ (R = Et, 5a and 5a′; ⁱPr, 5b), and [Ag₄(μ₃-Cl)(dppe)_1.5{S₂P(OR)₂}₃]_∞ (R = Et, 6a; ⁱPr, 6b). Compounds 5a, 5b, 6a and 6b were reported earlier [C.W. Liu, B.-J. Liaw, L.-S. Liou, J.-C. Wang, Chem. Commun. (2005) 1983]. Further increase in the chain length to four methylene units in 1,4-bis(diphenylphosphino)butane (dppb) yielded dppb-bridged polymers, [Ag(dppb){S₂P(OEt)₂}]_∞ (7) and [Ag₂(dppb){S₂P(OEt)₂}₂]_∞ (8). In all the polynuclear compounds, diphosphines acted as P,P′-bridging ligands, while the dtp ligands (S,S′-donors) adopted varieties of coordination patterns: S,S′-chelating (5, 7), S,S′-bridging (4), bimetallic-triconnective, μ₂:η²,η¹ (1, 3, 8), bimetallic-diconnective, μ₂:η² (2, 3) and trimetallic-triconnective, μ₃:η²,η¹ (6). Some of the complexes exhibit argentophilicity with Ag?Ag distances in the range, 2.918-3.360 Å. Concomitant bridging of two silver atoms either by dppm and dtp ligands (1, 3 and 4) or two dtp ligands (8) lead to close silver-silver contacts. The diphosphines (dppe and dppb) with longer spacer appeared to favor 1D or 2D polymers due to the flexibility of the spacer within the diphosphine unit by adopting anti conformation as opposed to syn conformation of the dppm linker is revealed in complexes.