硫酸钠-过氧化氢-水三元体系液固相平衡的神经网络模拟

将神经网络应用于液固体系相平衡,建立了283K和288K下Na2SO4-H2O2-H2O三元体系的BP神经网络模型,网络的训练结果偏差平方和分别为7 2×10-5和4 1×10-5,网络模型仿真的结果与实验值能够很好的吻合,所建能较好地描述该体系液固相平衡的溶解度数据.     

Degradation of chlorophenol by in-situ electrochemically generated oxidant

A novel in-situ electrochemical oxidation method was applied to the degradation of wastewater containing chlorophenol. Under oxygen sparging, the strong oxidant, hydrogen dioxide, could be in-situ generated through the reduction of oxygen on the surface of the cathode. The removal rate ofchlorophenol could be increased 149% when oxygen was induced in the electrochemical cell. The promotion factor was estimated to be about 82.63% according to the pseudo-first-order reaction rate constant (min-1). Important operating parameters such as current density, sparged oxygen rate were investigated.Higher sparged oxygen rate could improve the degradation of chlorophenol. To make full use of oxygen, however, sparged oxygen rate of 0.05 m3/h was adopted in this work. Oxidation-reduction potential could remarkably affect the generation of hydrogen peroxide. It was found that the removal rate of chlorophenol was not in direct proportion to the applied current density. The optimum current density was 3.5 mA/cm2 when initial chlorophenol concentration was 100 mg/L and sparged oxygen rate was 0.05 m3/h.     

顶空气相色谱法测定化妆品中甲醇

本文采用顶空气相色谱法测定化妆品中甲醇的含量。用氢火焰离子化检测器检测，化妆品中甲醇的最低检测浓度为1．5mg／kg，在样品中加标量分别为20mg和40mg时，回收率为91．9％-95．2％，依本法取两份样品分别测6次，变异系数为1．6％-2．8％。     

Carnosine and taurine contents in individual fibres of human vastus lateralis muscle

Analysis of ATPase characterized type I and type II fibres from biopsy samples of the vastus lateralis muscle of four male subjects showed a selective distribution of carnosine and free taurine similar to that observed in other species. The mean carnosine concentration was twice as high in type II compared with type I muscle fibres (23.2 +/- 17.8 and 10.5 +/- 7.6 mmol . kg -1 dry weight, respectively), while taurine was four times higher in type I compared with type II muscle fibres (39.2 +/- 17.8 and 9.6 +/- 2.6 mmol . kg -1 dw, respectively). Overlap in the concentration of carnosine or taurine between fibre types occurred only once in one subject. There was no overlap between fibre types in the ratio of carnosine to taurine. Higher carnosine concentrations in type II fibres will result in a greater contribution to the buffering of H+ arising from anaerobic metabolism. The contribution in a type II fibre with the highest carnosine content was estimated to equal 28% of that from other sources.     

A quantum chemistry study on reaction mechanisms of SO2 with O3 and H2O2

Reaction mechanisms of SO2 with O3 and H2O2 were investigated using quantum chemistry ab initio methods. Structures of all reactants, products, and transition states were optimized at the B3LYP/6-311G＋（3df,2p） level, and energy calculations were made at the G2M level. SO2 reactions with O3 and H2O2 occurred by O-abstraction and OH-abstraction by SO2, respectively, at length forming SO3＋O2 （3Eg） and H2SO4. For SO2＋O3 reactions the barrier height was predicted to be 9.68 kcal/mol with a rate constant of 3.61 × 10^-23 cm^3/（molecule.s） at 300 K, which is below the experimental upper limit. The rate constant predicted for this reaction accords well with the one provided by National Institute for Standards and Technology （NIST） in 250-500 K. For SO2＋H2O2 reactions the barrier height was predicted to be 62.39 kcal/mol with a rate constant of 2.48× 10^-61 cm^3/（molecule.s） at 300 K.     

Hydrogen transfer reduction of ketones using formic acid as a hydrogen donor under hydrothermal conditions

The hydrothermal experiments with ketones and formic acid showed that the hydrogen transfer reduction of ketones can be conducted using formic acid as a hydride donor in the presence of NaOH at 300 ℃. The yield of alcohols was considerably higher at a much lower ratio of hydrogen source to ketones than the traditional Meerwein-Ponndorf-Verley （MPV） reduction, reaching 60% for isopropanol from acetone and 70% for lactic acid from pyruvic acid. Water molecules may act as a catalyst in the hydrogen transfer reduction of ketones under hydrothermal conditions.     

二维超分子配位化合物[Cu（mal）（tpm）（H2O）]·2H2O的合成、结构及表征

合成了氢键连接的二维超分子配位化合物[Cu（mal）（tpm）（H2O）]·2H2O（mal=丙二酸,tpm=三吡唑甲烷）,并用元素分析和电子顺磁共振谱进行了表征。X射线单晶衍射表明该化合物的晶体属单斜晶系,Cc空间群,晶胞参数a=1．3624（2）nm,b=0．79318（14）nm,c=1．7526（3）nm,α=90°,β=102．352（3）°,γ=90°,V=1．8501（6）cm^3,Z=4。中心Cu（Ⅱ）离子为五配位,处于扭曲的四方锥配位环境中。晶格水与配位水形成较强的氢键将配合物连接成二维超分子结构。     

酶与二氧化锰对过氧化氢催化分解作用的比较

过氧化氢在常温下分解缓慢,但在催化剂存在时反应明显加快．已经证明某些生物体内含有过氧化氢酶,如马铃薯体和动物的肝脏等．通过定量实验设计,利用手持技术对反应进程中的气压变化进行测量,建立了在过氧化氢酶以及二氧化锰催化下过氧化氢分解反应的动力学方程。研究结果表明,过氧化氢酶的催化能力大大强于二氧化锰这一常用的化学催化剂．     

密闭式种猪舍部分有害气体分布状况观测

本研究对一栋密闭式种猪舍部分有害气体的分布状况进行了观测,结果表明,在舍内0.2m、0.5m和0.8m的不同高度层中,氨气的平均浓度分别为6.7mg/kg、8.9mg/kg和4.7mg/kg,其中,0.5m高度层氨气浓度显著高于0.8m高度层的(P＜0.05),日高峰值出现在6:00时的0.5m高度层,为17.6mg/kg;硫化氢的平均浓度分别为0.16mg/kg、0.15mg/kg和0.13mg/kg,各浓度间差异不显著性(P＞0.05),日高峰值出现在14:00时的0.2m高度层,为0.25mg/kg.整个试验期间氨气和硫化氢最高浓度和日平均浓度均低于畜禽环境空气质量标准.     

催化动力学光度法测定痕量钛

在HCl-NaAc(pH=0.90)酸性介质中,以钛催化过氧化氢氧化苯基荧光酮为指示反应,建立了一种催化动力学光度法测定痕量钛的新方法,并尝试用于测定大米、头发中的痕量钛(Ⅳ)。结果表明,在实验确定的最佳条件下,该方法的最低检出限为2.61×10-6 g/L,相对标准偏差为2.05%,测定的线性范围为(0.01～0.08)mg/L,结果令人满意。