Three-dimensional structural features and the toxicity of aminobenzenes and phenols

There are many organic pollutants in the environment, such as polychlorinated biphenyl, polycyclic aromatic hydrocarbons, dichlorodiphenyl-trichloroethane (DDT), and polychlorinated naphthalene. These organic pollutants are persistent,liposoluble and easily cumulated in organism; consequently, the potential toxicity will be high. Risk assessment of industrial chemicals is currently carried out using scanty experimental data, because many of these chemicals have very little or no test data. S…     

Classification of cultivation area of ginseng by near infrared spectroscopy and ICP-AES

A rapid and nondestructive near infrared (NIR) method using soft independent modeling of class analogy (SIMCA) for the classification of cultivation area (Korea and China) was evaluated and confirmed. Raw, first, and second derivative NIR spectra were compared to develop a robust classification rule. The chemical properties of ginseng samples were also investigated to find out the differences between Korean samples and Chinese samples. These differences make NIR spectroscopic method viable. The average value of each Korean and Chinese ginseng sample for crude fiber, crude protein, starch, and 10 inorganic constituents were measured and compared with F-test and t-test. The inorganic constituents were also measured by induced coupled plasma-atomic emission spectroscopy (ICP-AES). It could be found that the amount of starch and ten inorganic elements for example Na, Mg, P, K, Ca, Mn, Fe, Ni, Cu and Zn in ginseng samples are considerably different based on cultivation area. SIMCA has been applied to the inorganic data to investigate the possibility of ICP-AES as classification tool. However, it was observed that the result was not equal to than NIR spectra data. The overall results showed the availability of NIR method using SIMCA would be adequate for classification of cultivation of ginseng, since NIR spectra includes useful and various information on chemical properties in spite of broad and overlapped bands.     

Oxidation kinetics of timahdit and tarfaya moroccan oil shales

Organic matter evolution and kinetics of combustion of Tarfaya and Timahdit oil shales have been examined by thermogravimetry (TG) and by differential thermal analysis (DTA). An agreement is observed between both techniques where it was found that combustion of organic matter occurs in two steps. Kissinger's method applied on experimental results gives an activation energy of the same magnitude for the first step of both oil shales (103 kJ mol^–1) whereas the second is 148 kJ mol^–1 for Timahdit and 118 kJ mol^–1 for Tarfaya.The changes in specific surface area during thermal combustion of Timahdit and Tarfaya oil shales have been studied by thermogravimetric gas sorption balance and correlated with experimental results obtained on TG/DTA in air. For Timahdit oil shale oxidation products, specific surface areas calculated from nitrogen adsorption data shows a slight increase during the temperature domain of 280 to 430°C and after this temperature, they increase sharply. However, data obtained with Tarfaya oil shales shows a significant increase at the temperature of maximum oxidation of the first stage of combustion of organic matter.This revised version was published online in November 2005 with corrections to the Cover Date.     

Monodisperse chloromethyl-functionalized macroporous polymer particles by seeded polymerization in aqueous media

This study presents a method to produce monodisperse chloromethyl-functionalized macroporous poly(styrene-co-divinylbenzene) polymer particles by seeded polymerization in aqueous media. We observed that the molecular structure of polystyrene seed particles, the composition of the secondary monomer mixtures, and the type of solvents were very important factors that determine the morphology and porosity of the final particles. This study proposes that the molecular chemistry of polystyrene seed polymers, increasing molecular weight or crosslinking, is another factor that can control the porosity of the final particles. Also, the selection of a poor solvent was effective in forming the larger surface area. In this study, it was confirmed that the chloromethyl groups introduced on the surface of porous particles were quantified chemically and their effective incorporation had a close relationship with the surface area.     

Biotechnological storage and utilization of entrapped solar energy

Our laboratory has recently developed a device employing immobilized F₀F₁ adenosine triphosphatase (ATPase) that allows synthesis of adenosine triphosphate (ATP) from adenosine 5′-diphosphate and inorganic phosphate using solar energy. We present estimates of total solar energy received by Earth’s land area and demonstrate that its efficient capture may allow conversion of solar energy and storage into bonds of biochemicals using devices harboring either immobilized ATPase or NADH dehydrogenase. Capture and storage of solar energy into biochemicals may also enable fixation of CO₂ emanating from polluting units. The cofactors ATP and NADH synthesized using solar energy could be used for regeneration of acceptor d-ribulose-1,5-bisphosphate from 3-phosphoglycerate formed during CO₂ fixation.     

Effect of Inorganic Ions on Oleate Adsorption at a Nigerian Hematite–Water Interface

Using “pure” natural hematite selected from a high silica Nigerian hematitic ore, oleate adsorption densities at the hematite–water interface were determined in the presence of various inorganic ions (anions and cations) of different charges and at varying concentrations. Adsorption density was determined using electrical conductivity measurements. The specific surface area of the hematite particles was determined using the method of adsorption of paranitrophenol in aqueous solution. Inorganic ions in solution depressed oleate adsorption at the aqueous hematite surface. The charge of the ion proved to be the dominant factor determining the depression of oleate adsorption. Ionic strength also was an influence, up to a limiting value at which monolayer oleate coverage of the hematite surface occurred. The inorganic ions in solution are considered to function through nonspecific adsorption in the diffuse region of the electric double layer.     

碱性水蒸气处理的ZSM-5沸石酸性质及孔结构的影响

 采用XRD，NH3－TPD，比表面积和孔结构测定等研究了在不同温度下用含10％NH3的水蒸气处理时HZSM－5沸石n（Si）／n（Al）＝25）酸性质及孔结构的变化规律．结果表明，随着处理温度的提高，HZSM－5的结构未发生明显的变化；样品的总酸量下降很快，但弱酸分布量相对提高，而强酸分布量相对下降；提高处理温度，样品的比表面积和微孔体积减小，二次孔或中孔体积及外表面积有增大的趋势．     

高比表面积窄孔分布氧化铝的制备研究 Ⅰ.沉淀条件的影响

 以硫酸铝液为原料，以氨水、氢氧化钠和铝酸钠为碱沉淀剂，采用pH摆动法制备了高比表面积、大孔径、窄孔分布、大孔体积氧化铝，考察了沉淀剂、沉淀温度及沉淀时酸侧pH值对氧化铝物性的影响，并对pH摆动法与等pH沉淀法的结果进行了比较．结果表明，通过改变制备参数可以获得高比表面积、大孔体积的氧化铝，当沉淀温度为70℃，pH摆动3或4次时，氧化铝的孔体积可高达1．0ml／g，比表面积仍大于300m2／g．用pH摆动法制得的样品比用等pH沉淀法制得的样品容易酸溶，对挤压成型有利．不同样品在酸溶液中的分散性表明，用氨水沉淀剂可获得相对较小的沉淀粒子．改变沉淀时酸侧的pH值，可导致沉淀粒子的结构发生变化．     

云南两高辐合背景下低涡强降水过程对比分析

基于气象观测和欧洲中期天气预报中心第五代大气再分析资料（ERA5）,选取2018—2020年发生在云南的3次两高压辐合区（以下简称两高辐合）背景下低涡连续性强降水过程进行对比分析,探究其环流形势、动热力因子及水汽辐合的相似性和差异性.结果显示：(1)夏半年西太平洋副热带高压（以下简称西太副高）西伸时,云南常受两高辐合影响,当辐合区中有低涡生成,易发生连续性强降水,且强降水落区并不完全分布在整个狭长的两高辐合区内.(2)两高辐合区低涡降水具有相似的雨带分布和移动特征,但雨带的集中程度、分布范围、小时雨强和总雨量存在差异.强降水开始时,落区偏东,随着西太副高西伸及东北引导气流的引导,低涡向南向西移动,强降水落区也随之向南向西移动.低涡在某一地区徘徊导致降水集中在该区域,且西太副高西伸较强时,两高辐合形势更强,低涡降水大雨及以上量级雨带也更窄.(3)低涡造成的降水主要分布在低涡中心及低涡切变附近,且降水发生在低层暖湿的环境中,低层及中高层有冷空气侵入时,小时雨强的极端性更强,降水落区也相对偏北.两高辐合区低涡降水落区与水汽辐合区对应较好,水汽辐合强度较弱时,对应的总降水量较小.