氢气泡模板电沉积多孔金属镍薄膜

Porous nickel films have been successfully electrodeposited using cathodic hydrogen bubbles as a template. The influence of deposition parameters including concentration, temperature and current density on the films morphologies has been systematically studied. SEM results showed that increase in current density resulted in the deposits with higher pore density and smaller pore size. Both the pore size and thickness of the pore walls increased with the electrolyte temperature range from 20 to 60 ℃ when the other deposition parameters were fixed. Increasing the concentration of NiCl₂ or NH₄Cl in the electrolyte led to the thicker of the pore walls and declined pore size and density. The deposits displayed a dendritic morphology in cross-sectional SEM image. Electrochemical characterization of the porous nickel films after surface oxidation in 1.0 mol·L^-1 NaOH solution showed that specific capacitance as high as 7.2 F·g^-1 could be reached.     

纳米晶构筑一维多孔氧化锌的合成与表征

One-dimensional porous zinc oxide was prepared via the calcination of zinc oxalate precursor obtained by solvothermal method. The products were characterized by XRD, SEM, TEM, photoluminescence (PL) spectrum and nitrogen adsorption-desorption. The results show that the obtained zinc oxide sample is porous and constructed by nanoparticles about 30 nm in size. The specific surface area and total pore volume are 126 m²·g^-1 and 0.13 cm³·g^-1, respectively． The PL properties related with defects in ZnO nanoparticles were discussed for porous zinc oxide samples.     

类普鲁士蓝为前驱体制备纳米NiO及其电化学电容行为

Nanosized nickel oxide was synthesized by immersing the precursor NiHCNFe into 1 mol·L^-1 KOH solution to obtain nickel hydroxide (Ni(OH)₂) and then annealing in air at 300 ℃. X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests showed the prepared samples were rhombohedral crystalline structure of NiO with uniform grain and with a diameter of about 8 nm. Electrochemical properties of NiO were examined by cyclic voltammetry, ac impedance and galvanostatic charge-discharge tests. The results demonstrated that nickel oxide had a good capacitive behavior and cyclability due to its nanostructure. The highest specific capacitance of nickel oxide was about 303 F·g^-1 at a charge/discharge current density of 5 mA·cm^-2 in 6 mol·L^-1 KOH solution.     

Arsenic Speciation in Plant Samples from the Iron Quadrangle, Minas Gerais, Brazil

Several plants, especially ferns, have been shown to tolerate and accumulate high arsenic concentrations in soils. The leaves and roots of the ferns Pteris vittata (Chinese brake) and Pityrogramma calomelanos as well as a medical plant (Baccharis trimera) were sampled together with their associated soils in a region impacted by ore mining, the Iron Quadrangle in Brazil, where arsenic concentrations in the soils vary sharply (6–900 μg g⁻¹). The bioaccumulation factors were found to be low compared to the literature data, which can be explained by the low water-soluble fraction of arsenic in soil. The arsenic species in the plants were mainly arsenite. In comparison to the rhizoid samples, the concentrations of arsenic were higher in the leaves of the fern samples. The medical plant behaved differently. The bioaccumulation factor was low (0.7), and trimethylarsine oxide was detected as the third arsenic species beside arsenite and arsenate in both the roots and the leaves.     

新型锂离子电池正极材料LiVOPO4的制备与表征

Novel lithium-ion battery cathode material LiVOPO₄ was synthesized by sol-gel method using lithium hydroxide, ammonium metavanadate, phosphoric acid and citric acid as raw materials. The microstructure, surface morphology and electrochemical properties were characterized by various electrochemical methods in combination with thermogravimertric (TG) analysis and differential thermal analysis (DTA), X-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscope (SEM). Results show that the sample obtained by calcinating at 650 ℃ for 6 h is made up of uniform particles with size of 2～3 μm. The first discharge, charge capacity and columbic efficiency of LiVOPO₄ is 137.1 mAh·g^-1, 146.1 mAh·g^-1 and 93.8%, respectively. After 80 cycles the discharge capacity is kept at 130.4 mAh·g^-1, which is 95.1% of the first discharge capacity, and the capacity loss per cycle was only 0.061%, suggesting the LiVOPO₄ derived by this method is a promising cathode material for lithium ion batteries.     

锂离子电池正极材料LiNi1-xCoxO2的合成及电化学性能研究

LiNi_1-xCo_xO₂ cathode materials for lithium ion batteries were synthesized by the co-precipitation and solid-state reaction methods with LiOH·H₂O, Ni(NO₃)₂·6H₂O and Co(NO₃)₂·6H₂O as raw materials. The materials were characterized by XRD, SEM and electrochemical tests. The results showed that synthesized cathode materials were with layered structure similar to α-NaFeO₂ and uniform morphology and nearly normal grain size distribution and better electrochemical performance when x was 0.18. The first charge and discharge capacity of the cathode material was 224.3 mAh·g^-1 and 194.2 mAh·g^-1, respectively. 88.5% of the first discharge capacity remained at the 20th cycle.     

锂离子电池负极合金CoSn和Cu-Sn的制备与表征

CoSn alloy and Cu-Sn samples were synthesized by H₂-reduction following solid-state reaction between Co(Ⅱ)， Cu(Ⅱ)， Sn(Ⅳ) and NaOH at ambient temperature. The samples were characterized by XRD， SEM. The results showed that CoSn alloy (80～200nm) is globe-shaped， ultrafine hexagonal material， and Cu-Sn alloy powder consists of two phases， i.e. Cu₆Sn₅ and Cu₃Sn. Cu-Sn powder has spherical morphology and the particle size is estimated to be 60～70nm. The electrochemical performances of CoSn alloy and Cu-Sn powder were studied using lithium-ions model cell Li/LiPF₆ (EC+DMC)/CoSn (or Cu-Sn). It was demonstrated the reversible discharge capacities for 10 cycles keep above 280mAh·g^-1 for nanophase Cu-Sn， and 60mAh·g^-1 for CoSn alloy. Differ-ential capacity plots showed that the reaction mechanisms of Cu-Sn with lithium were reversible.     

共沉淀法制备负热膨胀性ZrW2O8粉体及其粒径控制初探

Negative thermal expansion (NTE) material ZrW₂O₈ powders were synthesized using co-precipitation route. The precursor of ZrW₂O₈ was studied by Thermogravimetric and differential scanning calorimetry (TG-DSC). The structure and morphology of the resulting powders were characterized by Powder X-ray diffraction (XRD) and Scanning electron microscopy (SEM), respectively. The results showed that the samples were single phase of α-ZrW₂O₈ with regular shape. High temperature X-ray diffraction measurement indicated that the thermal expansion coefficient of ZrW₂O₈ was -10.35 × 10^-6 K^-1 in the temperature range from room temperature to 150 ℃, -3.08 ×10^-6 K^-1 from 200 ℃ to 600 ℃ and the average value was -5.38 × 10^-6 K^-1. At the same time, polyethylene glycol (PEG) was used as dispersant to primary control the size of ZrW₂O₈.     

Ce0.8Y0.2O1.9-Ca3(PO4)2-K3PO4复合电解质在中温区的质子导电性及在常压合成氨中的应用

A precursor of Ce_0.8Y_0.2O_1.9(YDC) solid electrolyte was synthesized by the gol-gel method. YDC and phosphates powders were prepared by mixing the YDC and phosphates according to different weight ratios. The mixtures of the YDC and binary phosphates were ground and sintered at 1 400 ℃. The proton conductivity in solid electrolyte of the sintered samples was examined using electrochemical methods at 400～800 ℃. Ammonia was synthesized from nitrogen and hydrogen at atmospheric pressure in the solid state proton conducting cell reactor. The optimal condition for the ammonia production was determined. The result indicated that composite electrolyte of 80wt% YDC: 20wt% binary phosphates as proton conductor could obtain the highest ionic conductivity and ammonia production rate among the four samples, the rate of evolution of ammonia was up to 9.5 × 10^-9 mol·s^-1·cm^-2.     

铜/纳米金刚石复合物的结构及其对高氯酸铵热分解的催化作用

Nano-Copper and Cu/UDD (ultradispersed diamond) nanocomposites were separately prepared by reduction of CuCl₂ aqueous solution and that doped with 0.7%(weight percent) of ultra-dispersed diamond. The as prepared nano-crystals were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance techniques (EPR). It was found that homogeneous nucleation dominated the aqueous reduction reaction at high concentration and the diameter of nano-copper decreased as the reaction time shortened, yet at lower concentration heterogeneous nucleation predominated and the doped UDD functioned as heterogeneous nucleation. Otherwise large number of free-radicals existed in the nano-composites. Both of nano-copper and Cu/UDD nanocomposites were strong catalysts for AP decomposition, with Cu/UDD being a more effective one. The higher decomposition temperature for AP was 119 ℃ lower than that without catalyst. And the exothermic quantity of decomposition was from 590 J·g^-1 to 1 400 J·g^-1 by mix 2% of the Cu/UDD nanocomposites.     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.