Vapor-Liquid Equilibrium of 1-butanol-Alkanes System by Molecular Simulation

用Gibbs系综的Monte Carlo法模拟了正丁醇。正己烷和正丁醇-正庚烷体系的气液相平衡。在恒定压力0.496 6 MPa、0.294 0 MPa和0.1 MPa下,分别采用恒温恒压的Gibbs系综(NPT-Gibbs)模拟了不同温度下的气液相平衡。计算结果表明,模拟的数据比较准确,在一定温度范围内与实验结果吻合。The Vapor-Liquid equilibrium of 1-butanol/hexane and 1-butanol/heptane was measured by using Gibbs ensemble.The equilibrium data were obtained by the N-PT-Gibbs at the pressures of 0.4966 MPa,0.2940 MPa and 0.1 MPa.Comparing to the experimental data,the simulation results were quite good in some temperature range.国家自然科学基金(50573063);; 高等学校博士点专项基金(20050384013

Molecular simulation of transport behavior of penetrant through silicon-containing polymers

选择PCFF和COMPASS分子力场对橡胶态聚合物PDMS和玻璃态聚合物PS1体系进行模拟。COMPASS力场模拟得到的体系密度,O2和N2在PDMS与PS1中扩散系数更接近实验值。在模型大小一定时,Group-based求和法中截断距离越长,耗用机时越长,但对计算结果改进不大;截断距离为1.3nm时计算结果最好。Ewald方法耗时多而对计算结果却无明显改进。体系大小对扩散系数的计算值影响甚微。体积越小的分子,在聚合物中运动的范围越大,扩散系数越大。氧气和氮气分子在PDMS与PS1中运动轨迹不同,在PS1中氧气运动范围远大于氮气,而在PDMS中氧气运动范围稍大于氮气。小分子运动轨迹基本与聚合物自由体积分布对应,自由体积分数大,扩散系数也大。PCFF and COMPASS force fields were used to describe PDMS and PS1 polymeric systems and to estimate the diffusion coefficient of N2 and O2 through the PDMS and PS1 matrices at 298 K by molecular dynamics simulation.It was found that the COMPASS force field was better in describing the transport behavior of the penetrants.The calculated densities after refinement were in good agreement with the experimental results.The group-based and Ewald summation skills were used to estimate the non-bonded interaction between atoms.Calculation using the Ewald summation method took much longer time without bringing in obvious improvement in density estimation.Various cut-offs in using the group-based summation method did not produce densities with much difference, and the cut-off of 1.3 nm was the best.Two types of diffusions of the small molecules in the polymers were discussed.The diffusion of O2 and N2 in PDMS could be transformed from anomalous to normal motion in 30 ps; while their diffusion in PS1 would take 300 ps transforming from anomalous to normal state.The trajectories of diffusion of N2 and O2 in PDMS or PS1 were different.The motion area of O2 in the PS1 was much larger than N2; however, the former in the PDMS matrix was only slightly larger than the latter.The diffusions of O2 and N2 in the PDMS and PS1 were consistent with the free volumes of polymers.国家自然科学基金项目(50573063);; 高等学校博士点专项基金项目(20050384013)。~

Distribution Characteristics of Polycyclic Aromatic Hydrocarbons in Seawater from the South Yellow Sea

2007年9月进行了2007南黄海海洋环境调查,并采集各个调查站位的表层、中层、底层海水及表层沉积物。利用液-液萃取法对采集到的样品进行前处理,并用气相色谱-质谱法检测海水中的多环芳烃。结果显示,监测站位中表层海水中总多环芳烃的含量范围是15.76--233.39ng/l,南黄海中部海水中多环芳烃的组成以2环的萘为优势组分;各种多环芳烃的含量与国际生物学组织或国家制定的评价水生生物暴露于水体的安全食用标准相比虽未超标,但个别组分如荧蒽的含量已达到生态毒理评价标准。Marine surface sediments and sea water samples from the surface, middle and bottom layers were collected from the South Yellow Sea of China.The samples were pretreated by liquid-liquid extraction and the 16 polycyclic aromatic hydrocarbons (PAHs) in the samples were determined by gas chromatography-mass spectrometry (GC-MS).The results show that the range of total PAHs is 15.76～233.39 ng/L in surface water and PAHs in the water samples from central South Yellow Sea are dominated by naphthalene (2 rings).Content of PAHs compounds don′t exceed the safety guidelines proposed by International Biology Organization or governments, but the individual compound, such as fluoranthene content has reached eco-toxicological evaluation criteria.国家海洋局节能减排专项资助;中国海监技术支撑项目资助;海洋公益性项目资助(200705011

Advances in Structure Controls and Modifications of PIMs Membranes for Gas Separation

自具微孔高分子(POlyMErS Of InTrInSIC MICrOPOrOSITy,PIMS)是近年来出现的一种新型有机微孔材料,由含有扭曲结构的刚性单体聚合而成,具有比表面积高、化学和物理性质稳定、微孔结构可控等优点,在均相催化、氢气储存等方面表现出巨大的应用潜力。因其优越的气体分离性能,PIMS气体分离膜更是吸引了众多研究者的关注,发展迅速。本文总结了PIMS的分类及其在气体分离膜中的应用,重点介绍了PIMS气体分离膜的结构调控与改性方面的研究进展,分析了PIMS的分子结构与气体分离性能间的内在关联,最后提出了目前研究中存在的一些问题并对其发展做出了简要的评述。Polymers of intrinsic microporosity( PIMs),as novel microporous organic polymers polymerized by rigid monomers that have sites of contortion,have great application potential in homogeneous catalysis and hydrogen storage due to their high specific surface,chemical and physical stability and pore size controllability.Particularly,PIMs composed of polymer chains attract more attention in gas separation membranes due to their superior gas separation properties and good solubility.Here,the classification and applications of PIMs as well as the properties including stability,gas permeability and gas selectivity of PIMs gas membrane are introduced.The structure controls and modifications of PIMs gas membrane and the relationship between molecular structures and gas separation properties are described in detail.Finally,the problems existed in the present research are pointed out and a brief comment on the development is given.国家自然科学基金项目(No.21306155); 高等学校博士点专项科研基金(No.20120121120013); 中央高校科研业务费项目(No.2012121029)资助~

A Fully Flexible Potential Model for Carbon Dioxide

A fully flexible potential model for carbon dioxide has been developed to predict the vapor-liquid coexistence properties using the NVT-Gibbs ensemble Monte Carlo technique (GEMC). The average absolute deviation between our simulation and the literature experimental data for saturated liquid and vapor densities is 0.3% and 2.0%, respectively. Compared with the experimental data, our calculated results of critical properties (7.39 Mpa, 304.04 K, and 0.4679 g.cm(-3)) are acceptable and are better than those from the resealing the potential parameters of elementary physical model (EPM2). The agreement of our simulated densities of supercritical carbon dioxide with the experimental data is acceptable in a wide range of pressure and temperature. The radial distribution function estimated at the supercritical conditions suggests that the carbon dioxide is a nonlinear molecule with the C=O bond length of 0.117 nm and the O=C=O bond angle of 176.4 degrees, which are consistent with Car-Parrinello molecular-dynamics (CPMD), whereas the EPM2 model shows large deviation at supercritical state. The predicted self-diffusion coefficients are in agreement with the experiments.National Natural Science Foundation of China [50573063]; Program for New Century Excellent Talents in University of the State Ministry of Education [NCET-05-0566]; Specialized Research Fund for the Doctoral Program of Higher Education of China [2005038401

Comparison of Recoveries of PAHs Obtained by Ultrasound-assisted Extraction from Wet and Freeze-dried Marine Sediment

以美国环保局(EPA)优先控制的16种多环芳烃(polycyclic aromatic hydrocarbons,PAHs)为研究对象,建立了湿法超声波辅助萃取技术提取沉积物中痕量PAHs的可靠方法,对萃取剂、萃取功率、萃取次数和萃取时间进行了优化。并与传统干法超声辅助萃取进行了比较,湿法超声波辅助萃取的PAHs回收率为57%～125%,而干法超声波辅助萃取PAHs的回收率为48%～113%,对相对分子质量小的PAHs如萘～芴的回收率,湿法明显高于干法。该文建立的湿法超声辅助萃取适用于沉积物和泥土中痕量PAHs的快速测定。An ultrasound-assisted extraction method for the extraction of 16 trace PAHs(USEPA priority pollutant) from wet(i.e.untreated) marine sediment was developed.The effects of solvent type,power of ultrasound,and extraction time were studied and optimized.The developed method was compared with the traditional ultrasound-assisted extraction for freeze-dried sediment.The results showed that recoveries of sixteen PAHs extracted from the wet marine sediment ranged from 57% to 125%,whereas those extracted from the freeze-dried marine sediment ranged from 48% to 113%.The results also indicated that the recoveries of PAHs with smaller relative molecular mass(e.g.naphthalene and fluorine) extracted from the wet sediment were higher than those from the freeze-dried sediment.Thus the developed method was appropriate for rapid determination of trace PAHs in marine sediment and soil.海洋公益性行业科研专项(200705011);; 中国海监技术支撑体系项目;; 2008年海洋环境保护及节能减排专

Concentration and distribution of polycyclic aromatic hydrocarbons in surface sediments collected in the Southern Yellow Sea

采用气相色谱与质谱联用(gC/MS)技术,在一个航次内对南黄海表层沉积物中16种优先监控的PAHS的污染状况进行了调查,采用菲/蒽、荧蒽/芘、荧蒽/(荧蒽+芘)、吲哚芘/(吲哚芘+苯并(g,H,I)苝)等特定比值对PAHS来源进行了分析.结果表明,南黄海表层沉积物中检出PAHS的总含量为90.4~732.65ng·g-1,各站点均以4~6环为主;与其它站位相比,倾废区的H01站位受到PAHS污染较为明显,无论是16种PAHS总量还是高分子量组分最高值都出现在该站点,虽然该海区沉积物中PAHS的含量没有超出生物影响低值,但苯并(b)荧蒽、吲哚芘和苯并(g,H,I)芘等一些没有最低安全标准的PAHS也有不同程度的检出,对海洋生物具有潜在的毒副作用.PAHS可能来源于原油、生物和煤燃烧造成的污染.The concentrations of sixteen representative Polycyclic Aromatic Hydrocarbons(PAHs) in surface sediment samples collected from the Southern Yellow Sea were determined by GC-MS.The distribution and potential sources of PAH contamination in the region were investigated.The types of PAHs found in the surface sediments were mainly 4～6 ring PAHs,and they are unevenly distributed among the different sampling sites covering an area of 139 km2.The area is known for continuous waste dumping activities in recent years,and indeed sites adjacent to such activities were found to have high levels of PAHs.Some high molecular weight PAH compounds such as benzo$$b$$fluoranthene,dibenzo$$a,h$$anthracene and benzo$$g,h,i$$perylene were detected in some samples.The health implication of these contaminants needs careful assessment since toxicity guidelines are not available for these species.The potential sources of PAHs are discussed using various source-specific PAH indexes such as Phenathrene/Anthracene、Fluoranthene/Pyrene、Fluoranthene/(Fluoranthene+Pyrene) and Indeno [1,2,3-cd] pyrene/(Indeno[1,2,3-cd] pyrene+Benzo [g,h,i] perylene).The composition of the observed PAHs reflects that they originate from both petroleum utilization and incomplete combustion.海洋公益性行业科研专项(No.200705011);中国海监技术支撑体系项目;2008年海洋环境保护及节能减排专项---

抗H5亚型禽流感病毒单链抗体在毕赤酵母中的分泌型表达和生物活性分析

在本实验室研制出的多株针对H5N1亚型禽流感血凝素单抗中,13D4单抗对所有H5亚型病毒均有血凝抑制和中和活性,具有特异性高、反应性强和识别广的特点,且在小鼠实验中显示了对各种代表株禽流感的感染和发病均具有良好的治疗效果。在此研究基础上,本实验通过基因工程构建含有13D4单链抗体(scFv)基因的毕赤酵母表达载体,实现目的蛋白的分泌性表达和纯化。经过竞争法和血凝抑制检测其活性,表明获得的单链抗体具有与原始鼠源抗体相近的反应活性和相同的识别表位。H5N1广谱中和单抗13D4的单链抗体的成功构建,为进一步研制针对H5N1禽流感病毒的治疗性抗体奠定了基础

Investigation of Structures of the Self-assembled Pseudorotaxane of Cucurbiturils with Some Alkyldiamines

以1H核磁共振技术和X射线单晶衍射分析方法考察了 3种瓜环与长链二胺 ( 1,7 庚二胺与 1,8 辛二胺 )相互作用的结构特征 .1HNMR分析表明瓜环 (Q[6]和Q[7] )与有机二胺 ( 1,7 庚二胺与 1,8 辛二胺 )有较强的相互作用 ,形成自组装类轮烷结构 ;Q[8]与 1,7 庚二胺与 1,8 辛二胺之间相互作用力相对较弱 ;晶体结构测定结果表明 ,六元瓜环与辛二胺自组装形成的类轮烷实体中 ,辛二胺是以直链状穿过六元瓜环的空腔 ,两配位氨基留在瓜环两端口之外 .The structures of self-assembled pseudorotaxane of cucurbit[n]urils(n=6～8) with some alkyldiamines have been investigated by 1H NMR technique and single crystal X-ray diffraction method. The results reveal that the interaction between cucurbit[6]uril or cucurbit[7]uril and 1,7-diaminoheptane or 1,8-diaminooctane is stronger than that between cucurbit[8]uril and 1,7-diaminoheptane or 1,8-diaminooctane, and the pseudorotaxanes of cucurbit[n]urils with the alkyldiamines were observed. Particularly, in the pseudorotaxane of cucurbit[6]uril with 1,8-diaminooctane, the amino groups of 1,8-diaminooctane are left outside the ports of cucurbit[6]uril.国家自然科学基金(No.200261002);; 贵州省重点基金(No.20023004);; 贵州省国际合作(No.200211003)资助项目

Challenge by Head Transplant

范瑞平：诸位好!受《中国医学伦理学》杂志王明旭主编所托,组织一篇＂换头术的挑战＂争鸣笔谈,特邀各位参与。请踊跃发表意见,观点不拘,长短不限,畅所欲言,各抒己见,若能针对已发观点形成争论,则更能增加读者兴趣