检索结果-南通市图书馆

Geochemical simulation of the formation of brine and salt minerals based on Pitzer model in Caka Salt Lake

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2004年第8期47卷 720-726页

作者： LIU Xingqi1, CAI Keqin2.& YU Shengsong3 1. Nanjing Institute of Geography and Limnology, chinese academy of Sciences, Nanjing 2.0008, China 2. China University of Geosciences, Beijing 100083, China 3. Institute of Salt Lakes, chinese academy of Sciences, Xining 810008, China Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing China China University of Geosciences Beijing China Institute of Salt Lakes Chinese Academy of Sciences Xining China

The geochemical simulation of the formation of brine and salt minerals based on Pitzer model was made in Caka Salt Lake. The evolution of the mixed surface-water and the mineral sequences were calculated and compared with the hydrochemical compositions of the brine and the salt minerals of the deposit in Caka Salt Lake. The results show that the formation temperature of the lake is between 0°C and 5°C, which is well identical with other studies. The mixing of salt-karst water with the surface waters, neglected by the former researchers, is very important to the formation of the lake, indicating that the initial waters resulting in the formation of the lake are multi-source. It is the first time to use Pitzer model in China for making geochemical simulation of the formation and evolution of inland salt lake and satisfactory results have been achieved.

关键词： Pitzer model,Caka Salt Lake,geochemical simulation,salt-karst water.

Kinetics and reaction mechanism of phenol hydroxylation catalyzed by La-Cu_4FeAlCO_3

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2005年第6期48卷 530-537页

作者： CHEN Chunxia1,2. XU Chenghua1, FENG Liangrong1, SUO Jishuan1 & QIU Fali1 1. Chengdu Institute of Organic Chemistry, chinese academy of Sciences, Chengdu 610041, China 2. Graduate School of the chinese academy of Sciences, Beijing 100039, China Chengdu Institute of Organic Chemistry Chinese Academy of Sciences Chengdu 610041 China

The present work synthesizes La-Cu4FeAlCO3 catalyst under microwave irradiation and characterizes its structure using XRD and IR techniques. The results show that the obtained La-Cu4FeAlCO3 has a hydrotalcite structure. In the phenol hydroxylation with H2.2.catalyzed by La-Cu4FeAlCO3, the effects of reaction time and phenol/H2.2.molar ratio on the phenol hy-droxylation, and relationships between the initial hydroxylation rate with concentration of the catalyst, phenol, H2.2.and reaction temperature are also investigated in details. It is shown the phenol conversion can reach 50.09% (mol percent) in the phenol hydroxylation catalyzed by La-Cu4FeAlCO3, under the reaction conditions of the molar ratio of phenol/H2.2.1/2. the amount ratio of phenol/catalyst 2., reaction temperature 343 K, reaction time 12. min, 10 mL distilled water as solvent. Moreover, a kinetic equation of v = k[La ? Cu 4 FeAlCO 3 ][C 6 H 5 OH][H 2.O 2.. and the activation energy of Ea=58.37 kJ/mol are obtained according to the kinetic studies. Due to the fact that the HO-Cu+-OH species are detected in La-Cu4FeAlCO3/H2.2.system by XPS, the new mechanism about the generation of hydroxyl free radicals in the phenol hydroxylation is pro-posed, which is supposed that HO-Cu+-OH species are transition state in this reaction.

关键词： rare earth, hydrotalcite, microwave irradiation, phenol hydroxylation, kinetics, reaction mechanism.

Interfacial behaviors of PMMA-PEO block copolymers at the air/water interface

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2005年第6期48卷 567-573页

作者： CHENG Caixia1, JIAO Tifeng2. TANG Rupei1, LIU Minghua2.& XI Fu1 1. State Key Laboratory of Polymer Physics and Chemistry, Joint Laboratory of Polymer Science and Materials, Institute of Chemistry, chinese academy of Sciences, Beijing 100080, China 2. CAS Key Laboratory of Colloid and Interface Science, Institute of Chemistry, chinese academy of Sciences, Beijing 100080, China State Key Laboratory of Polymer Physics and Chemistry Joint Laboratory of Polymer Science and Materials Institute of Chemistry Chinese Academy of Sciences Beijing China CAS Key Laboratory of Colloid and Interface Science Institute of Chemistry Chinese Academy of Sciences Beijing China

Diblock copolymer of PMMA2.1-b-PEO114 and triblock copolymer of PMMA12.-b- PEO2.7-b-PMMA12. were synthesized and their interfacial properties at the air-water interface were investigated, where both blocks of polyethylene oxide (PEO) and poly(methyl methacrylate) (PMMA) are surface active but the former is soluble in water while the latter is not. Both the block copolymers could form monolayers with two obvious transition regions. The first transition point is around 10 mN/m, which could be assigned to the pancake-brush change of the PEO chains. The other is around 18 mN/m, which could be ascribed to the condensed packing of PMMA. The surface morphological changes during the compression of the Langmuir monolayers are inves-tigated by using the AFM and SEM methods for the films deposited at different surface pressure or molecular areas. At a lower surface pressure, a typical morphology of PEO-con- taining lipopolymers is observed. Upon compression, sphere-dominant morphologies were observed. While the diblock copolymer is easy to folding, the triblock copolymer is in favor of formation of circular domains through vesiculation.

关键词： PMMA-PEO, block copolymers, monolayer, Langmuir-Blodgett films, AFM.

An Alternative Explanation for a Screw-like Meteoric Train Photographed by Double-Station Observations

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Astronomy and Astrophysics 2007年第6期7卷 814-822页

作者： Guang-Jie Wu1,2.1 National Astronomical Observatories/Yunnan Observatory,chinese academy of Sciences,Kunming 650011 2.Purple Mountain Observatory,chinese academy of Sciences,Nanjing 2.0008 National Astronomical Observatories / Yunnan Observatory Chinese Academy of Sciences Purple Mountain Observatory Chinese Academy of Sciences

Two-station observation of meteors, especially a meteor trains, provides an effective approach to the measurement of the physical parameters. We have collected four special groups of photographs of meteoric trains taken at two stations during Leonids 2.01. One representative group has been measured and analyzed in detail. An analysis has been reported in our first paper. In this paper, an alternative explanation for the screw-like meteoric train is suggested based on some physical calculations. The results reveal that this train has a screw-like structure and, apparently, spoke beams. The mother meteor of this train may be negatively charged and moves forward along a left-hand screw trajectory under the effect of the geomagnetic field. The spoke beams might be the visual effect of the long time exposure of many particles released from the disintegrated meteoroid.

关键词： meteors meteoroids -- magnetic fields

Simulations for terrestrial planets formation

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2009年第5期52卷 794-803页

作者： ZHANG Niu 1,2.&JI JiangHui 2.3 1Graduate University of chinese academy of Sciences,Beijing 100049,China 2.urple Mountain Observatory,chinese academy of Sciences,Nanjing 2.0008,China 3 National Astronomical Observatories,chinese academy of Sciences,Beijing 100012.China Graduate University of chinese academy of Sciences Beijing China Purple Mountain Observatory Chinese Academy of Sciences Nanjing China National Astronomical Observatories Chinese Academy of Sciences Beijing China

In this paper,the formation of terrestrial planets in the late stage of planetary formation is investigated using the two-planet *** that time,the protostar formed for about 3 Ma and the gas disk *** the model,the perturbations from Jupiter and Saturn are *** of the mass of outer planet,and the initial eccentricities and inclinations of embryos and planetesimals are also *** results show that,terrestrial planets are formed in 50 Ma,and the accretion rate is about 60%-80%.In each simulation,3-4 terrestrial planets are formed inside"Jupiter"with masses of 0.15 -3.6M⊕.In the 0.5-4 AU,when the eccentricities of planetesimals are excited,planetesimals are able to accrete material from wide radial *** plenty of water material of the terrestrial planet in the Habitable Zone may be transferred from the farther places by this *** could also happen a few times between two major planets only if the outer planet has a moderate mass and the small terrestrial planet could survive at some resonances over time scale of 10 8 *** one of our simulations,commensurability of the orbital periods of planets is very ***,a librating-circulating 3:2.configuration of mean motion resonance is found.

关键词： astrophysics exoplanet planetary formation n-body simulation

Adjoint method for the optimum planning of industrial pollutant sources

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2005年第8期48卷 1270-1279页

作者： LIU Feng1,2. HU Fei2.& ZHU Jiang2.1. College of Environmental Sciences, Peking University, Beijing 100871, China 2. LAPC, Institute of Atmospheric Physics, chinese academy of Sciences, Beijing 10002., China College of Environmental Sciences Peking University Beijing China LAPC Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

The optimum planning of industrial pollutant sources, which optimizes the economic object without violating environmental constraints, is an important and hard task to be conquered. In this paper, an adjoint method is developed to solve the problem. The penalty function is in-troduced to deal with the environmental inequality constraints, and Lagrange function is con-structed to derive the adjoint equation and the gradient of the object function. In this means, the gradient of the object function can be calculated by solving the adjoint equation, and the infor-mation from the gradient is used to make the object function descend and approach to an optimal solution after some iterations. A two-dimensional, simplified model is used for numerical experi-ments. The theoretical derivations are verified by the results of the experiments. Furthermore, the adjoint method is shown to be of excellent convergence and efficiency, which is adaptive to the fast development of air quality numerical models and super computers.

关键词： optimum planning, industrial pollutant sources, adjoint equation, penalty function, gradient.

Synthesis,characterization,properties and crystal structure of heterometallic 1D coordination polymers {[CuLZn·CuLZn(H_2.)]·H_2.}_n

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2006年第4期49卷 338-344页

作者： TAO Ruojie1, LI Fu’an1, ZANG Shuangquan1, CHENG Yanxiang2.& NIU Jingyang1 1. Chemistry and Chemical Engineering College of Henan University, Kaifeng 475001, China 2. Changchun Institute of Applied Chemistry, chinese academy of Sciences, Changchun 13002., China Chemistry and Chemical Engineering College of Henan University Kaifeng China Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun China

Copper-zinc heterometallic 1D chain coordination polymer has been synthesized and characterized by elemental analysis, and IR spectra etc. The crystal structure was determined by single-crystal X-ray diffraction analyses. The title complex is 1D chain coordination polymer with the chemical formula {[CuLZn·CuLZn(H2.)]·H2.}n, where H4L=N-(2.hydroxybenzamido)-N’-(3-carboxy- lsalicylidene)ethylenediamine. Its structural unit is comprosed of two tetranuclear cycles formed by two dissymmetrical tetranuclear units. These units polymerized each other to form 1D chain coordi- nation polymer.

关键词： copper, zinc, heterometallic coordination polymer, crystal structure.

A mixed method for measuring low-frequency acoustic properties of macromolecular materials

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2006年第6期49卷 729-739页

作者： LIU Hongwei1,YAO Lei1,3,ZHAO Hong1,3,ZHANG Jichuan2.3 & XUE Zhaohong2.1. National Key Laboratory of Acoustics,Institute of Acoustics,chinese academy of Sciences,Beijing 100080,China 2. Institute of Chemistry,chinese academy of Sciences,Beijing 100080,China 3. Graduate University of chinese academy of Sciences,Beijing 100049,China National Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of Sciences Beijing China Institute of Chemistry Chinese Academy of Sciences Beijing China

A mixed method for measuring low-frequency acoustic properties of macro-molecular materials is presented. The dynamic mechanical parameters of materials are first measured by using Dynamic Mechanical Thermal Apparatus(DMTA) at low frequen-cies,usually less than 100 Hz; then based on the Principles of Time-Temperature Super-position (TTS),these parameters are extended to the frequency range that acousticians are concerned about,usually from hundreds to thousands of hertz; finally the extended dynamic mechanical parameters are transformed into acoustic parameters with the help of acoustic measurement and inverse analysis. To test the feasibility and accuracy,we measure a kind of rubber sample in DMTA and acquire the basic acoustic parameters of the sample by using this method. While applying the basic parameters to calculating characteristics of the sample in acoustic pipe,a reasonable agreement of sound absorp-tion coefficients is obtained between the calculations and measurements in the acoustic pipe.

关键词： low-frequency acoustic properties,dynamic mechanical properties,Principles of Time-Temperature Superposition,acoustic pipe,sound absorption coefficient.

Infrared Galaxies in the Nearby Universe

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Astronomy and Astrophysics 2008年第6期8卷 643-652页

作者： Jian-Ling Wang 1 National Astronomical Observatories,chinese academy of Sciences,Beijing 100012.China 2.Graduate School of chinese academy of Sciences,Beijing 100049,China National Astronomical Observatories Chinese Academy of Science

We used the Sloan Digital Sky Survey （SDSS） Data Release 5 （DR5） to study the morphological properties of 1137 nearby infrared （IR） galaxies, most of which are brighter than 15.9 mag in r-band. This sample was drawn from a cross-correlation of the Infra-Red Astronomical Satellite （IRAS） point source catalog redshift survey with DR5 at z ≤ 0.08. Based on this IR galaxy sample, we constructed five volume-limited sub-samples with IR luminosity ranging from 10^9.5 L⊙ to 10^12.⊙. By deriving the IR luminosity functions （LF） for different morphological types, we found that normal spiral galaxies are the dominant population below LIR ~ 8 ~ 10^10 L⊙; while the fraction of barred spiral galaxies increases with increasing IR luminosity and becomes dominant in spiral galaxies beyond LIR ≈ 5 × 10^10L⊙. As the IR luminosity decreases, the IR galaxies become more compact and have lower stellar masses. The analysis also shows that normal spiral galaxies give the dominant contribution to the total comoving IR energy density in the nearby universe, while, in contrast, the contribution from peculiar galaxies is only 39%.

关键词： galaxies evolution galaxies interactions galaxies starburst infrared galaxies galaxies luminosity function