Influence of entrance channels on the formation of superheavy nuclei in massive fusion reactions

Within the framework of the dinuclear system (DNS) model, the production cross sections of superheavy nuclei Hs (Z=108) and Z=112 combined with different reaction systems are analyzed systematically. It is found that the mass asymmetries and the reaction Q values of the projectile target combinations play a very important role on the formation cross sections of the evaporation residues. Both methods to obtain the fusion probability by nucleon transfer by solving a set of microscopically derived master equations along the mass asymmetry degree of freedom (ID) and distinguishing protons and neutrons of fragments (2D) are compared with each other and also with the available experimental data. (C) 2010 Elsevier B.V. All rights reserved.

沈阳西郊污灌区农田铜锌铅污染特征分析

为评价污水灌溉区农田土壤重金属污染状况,采用单因子指数和综合多因子指数法,对沈阳西郊污灌区农田土壤重金属铜锌铅的污染特征进行了研究。结果表明,于洪区宁官、高明、胡孤家和四台子四个样点土壤均受到三种重金属污染,其中宁官点0～10 cm土层铜、锌、铅含量分别达到69.74 mg.kg-1、275.09 mg.kg-1和81.83mg.kg-1,分别是当地土壤背景值的2.82、4.59和3.60倍。各样点土壤有效态铜、锌、铅含量也远高于未受污染地区的平均含量,土壤铜、锌、铅有效态含量占全量的比例分别为4.65%～15.46%、1.36%～3.84%和5.46%～18.86%。说明沈阳西郊污灌区农田土壤重金属污染较严重,必须通过工程、生物及化学措施进行长期的污染治理。

Phase stability and thermophysical properties of neodymium cerium composite oxide

Nd2CexO3+2x (x = 2.25, 2.5, 2.75, 3.0) were synthesized by solid-state reaction, and their phase stabilities and thermophysical properties were investigated. The X-ray diffraction (XRD) results indicated that Nd2CexO3+2x with fluorite structure were stable after long-term annealing at 1673 K. They have higher thermal expansion coefficients (TECs) than yttria-stabilized zirconia (YSZ) which is the typical thermal barrier coating (TBC) material, especially the thermal expansion as a function of temperature is parallel to that of the nickel-based superalloy.

Potential-induced transformation for surfactant aggregates on a metal surface

Surfactant adsorption on metal surfaces has been used to limit the activity of the electrode surface and to stabilize colloidal clusters and nanoparticles in solution, but the adsorption and relative potential-induced structure change of the surfactant were not known. Here, the adsorption of sodium dodecyl sulfate (SDS) on a Au(111) surface under potential control was investigated by in situ scanning tunneling microscopy (STM). The STM images showed that the morphology of SDS on Au(111) was changed from a hemi-cylindrical micellar monolayer to a compact and uniform bilayer through control of the potential. The transition between the hemimicellar monolayer and the compact bilayer is not reversed after a period of time. The model of potential-induced transformation for SDS aggregates on Au(111) was established. (C) 2001 Elsevier Science B.V. All rights reserved.

A study of dimethylferrocene diffusion and electrode kinetics using microelectrode voltammetry in poly(ethylene glycol) solvent

The heterogeneous electron transfer rate constant (k(s)) of dimethylferrocene (DMFc) was estimated using cyclic voltammetric peak potential separations taken typically in a mixed diffusion geometry regime in a polyelectrolyte, and the diffusion coefficient (D) of DMFc was obtained using a steady-state voltammogram. The heterogeneous electron transfer rate constant and diffusion coefficient are both smaller by about 100-fold in the polymeric solvent than in the monomeric solvent. The results are in agreement with the difference of longitudinal dielectric relaxation time (tau(L)) in the two kinds of solvents, poly(ethylene glycol) (PEG) and CH3CN, indicating that k(s) varies inversely with tau(L); k(s), is proportional to D of DMFc. Both D and k(s) of DMFc in PEG containing different supporting electrolytes and at different temperatures have been estimated. These results show that D and k(s) of DMFc increase with increasing temperature in the polyelectrolyte, whereas they vary only slightly with changing the supporting electrolyte.

栉孔扇贝CfLITAF基因的克隆与表达分析

关于无脊椎动物中是否存在细胞因子一直都存在着异议。从细胞因子本身入手，运用细胞生物学和免疫学手段，已经在软体动物、节肢动物和棘皮动物等无脊椎动物中证实了高等动物细胞因子样活性物质的存在，然而利用分子生物学手段至今没有得到任何核苷酸或蛋白序列信息，而从与细胞因子相关的分子如调控其表达的转录因子入手来研究无脊椎动物中的细胞因子样物质的存在，或许会得到意想不到的惊喜。 最近从人的单核细胞系THP-1中分离纯化出一种新型的转录因子，它可以被LPS诱导表达，产生的蛋白在TNF-α的表达过程中起着非常重要的作用，因而命名为LPS-induced TNF-α factor（LITAF）。随后该基因在小鼠和鸡中也被克隆分离出来，其编码的蛋白已经证实在TNF-α的表达过程中起着不可或缺的作用。迄今为止，在无脊椎动物中还没有相关同源基因的报道。 本研究采用大规模EST测序方法，结合锚定PCR技术从栉孔扇贝体内克隆到了高等动物LITAF基因的同源基因CfLITAF的全长cDNA序列。该cDNA全长为1240bp，其中5' 非编码区（UTR）为112 bp；开放阅读框（Open Reading Frame, ORF）包括450 bp，编码149个氨基酸残基，该多肽的理论分子量为16.08 kDa，等电点为6.77；3' UTR为678bp，包含一个poly A尾巴。SMART结构域预测发现CfLITAF蛋白含有一个保守的LITAF结构域。实时定量PCR检测CfLITAF基因在栉孔扇贝主要免疫器官中的表达分布情况，发现在所检测的六种组织血细胞、外套膜、肌肉、心、腮、性腺中均能检测到CfLITAF基因转录本的不同丰度的表达。血淋巴和肌肉中的表达量相差不大，而在心、外套膜、腮和性腺中的表达量要高于血淋巴和肌肉中的表达量，分别是血中表达量的2.45、2.82、9.23和24.93倍。 为了验证其表达量是否会受到LPS的诱导，利用QRT-PCR（quantitative real time PCR）检测了CfLITAF基因在受到LPS和PGN刺激后在血细胞中的表达规律。结果如下：在LPS刺激后3h，CfLITAF的表达量显著上调，达到了原初水平的1.5倍，随着时间的延长，其表达量逐渐恢复到刺激前水平；在用PGN刺激血细胞后的9个小时内均没有检测到CfLITAF基因mRNA表达量的显著变化。实验中所用血细胞为同一批原代培养的栉孔扇贝血淋巴细胞，细胞活力通过台盼蓝拒染实验测定。 CfLITAF基因的克隆与表达分析，不仅为进一步认识栉孔扇贝的免疫防御机制提供了实验参考，更重要的是为无脊椎动物中细胞因子样物质的研究提供了一个分子水平上的线索，为无脊椎动物中细胞因子样物质的研究奠定了理论基础。

高温高压下H2O-CH4体系PVTx性质的分子动力学模拟研究

Geological fluids are important components in the earth system. To study thephysical chemistry properties and the evolution of fluid system turns out to be one of the most challenging issues in geosciences. Besides the conventional experimental approaches and theoretical or semi-theoretical modeling, molecular level computer simulation(MLCS) emerges as an alternative tool to quantificationally study the physico-chemical properties of fluid under extreme conditions in order to find out the characteristics and interaction of geological fluids in and around earth. Based on our previous study of the intermolecular potential for pure H2O and thestrict evaluation of the competitive potential models for pure CH4 and the ab initio fitting potential surface across H2O-CH4 molecules in this study, we carried out more than two thousand molecular dynamics simulations for the PVTx properties of pure CH4 and the H2O-CH4 mixtures. Comparison of 1941 simulations with experimental PVT data for pure CH4 shows an average deviation of 0.96% and a maximum deviation of 2.82%. The comparison of the results of 519 simulations of the mixtures with the experimental measurements reveals that the PVTx properties of the H2O-CH4 mixtures generally agree with the extensive experimental data with an average deviation of 0.83% and 4% in maximum, which is equivalent to the experimental uncertainty. Moreover, the maximum deviation between the experimental data and the simulation results decreases to about 2% as temperature and pressure increase,indicating that the high accuracy of the simulation is well retained in the high temperature and pressure region. After the validation of the simulation method and the intermolecular potential models, we systematically simulated the PVTx properties of this binary system from 673 K and 0.05 GPa to 2573 K and 10 GPa. In order to integrate all the simulation results and the experimental data for the calculation of thermodynamic properties, an equation of state (EOS) is developed for the H2O-CH4 system covering 673 to 2573 K and 0.01 to 10 GPa. Isochores for compositions < 4 mol% CH4 up to 773 K and 600 MPa are also determined in this thesis.

聚硅氯化铝铁（PSAFC）絮凝剂的形态分析

通过对聚硅氯化铝铁水解共聚物的合成制备及水解共聚过程PH变化的研究，对铝铁共物的化学形态、二氧化硅的加入和碱化度B对铝铁共聚物的影响进行了研究和讨论；并应用Ferron配合逐时比色法对聚合物中铁的形态进行了表征，为深入研究聚硅氯化铝铁铁奠定了理论基础。

氢化物发生-多接收杯电感耦合等离子体质谱同位素稀释法测定硒同位素

使用改进的巯基棉分离流程和^74硒-^77硒双稀释剂，在氢化物（HG）-多接收器电感耦合等离子体质谱仪（MC—ICP—MS）实现了高精度硒同位素组成的测定。巯基棉用于分离样品基质中的硒，随后使用HNO3＋H2O2消除干扰的有机质，^74硒-^77硒双稀释剂校正样品分离和质谱测定过程中的硒同位素质量分馏。硒标准溶液NIST SRM5149和MH495几个月的测定表明，该方法的外精度为0．1‰（2σ），样品的外精度为0．15‰～0．2‰（2σ）。以TCF分离硒的平均回收率85％计算，最小硒需要量为20ng。实验结果以相对于NIST SRM3149的δ^82／76Se表达，δ^82/76MH98/SRM3149=-3．44±0．1‰（2σ），优于已发表的数据δ^82/79MH495/SRM3149=-3．04±0．5‰。测定样品的δ82/76 SRM3149为-13．53‰～11．37‰，为硒同位素在环境、农业、生命和地球科学中的拓展应用与发展奠定了基础.

黑色岩系岩石样品中黑碳含量测定和误差分析

文章对黑碳的基本概念、研究现状和意义、及测定方法进行了综合评述，并将辉长岩和粉晶石墨标样按不同比例配成实验标样进行黑碳测量实验，证明实验方法具有较好的可行性；对不同类型的样品进行的额外氧化实验表明其氧化损失率是各不相同的；采用化学方法测量黑色岩系岩石样品中的黑碳含量为6．5821％，通过一次性定量黑碳实验流程和平行样品分步实验，测得实验偏差为3．77％。其中HF—HCl单步处理偏差为1．99％，而K2Cr2O7氧化处理单步实验的偏差为3．11％。实验表明测量黑色岩系岩石样品中黑碳含量的化学实验方法是行之有效的.

Gas phase derivatization of endohedral metallofullerenes R@C-82 and R-2@C-80 (R = Nd, Ce)

Endohedral metallofullerenes Ce@C-82, Ce-2@C-80, Nd@C-82 and Nd-2@C-80 undergo gas phase ion/molecule reactions with the ion system from self-chemical ionization of vinyl acetate, and exohedral derivatives are thus generated, A new heterocycle is formed from metallofullerenes and a C2H3O+ cation, Endohedral metallofullerenes show much higher reactivities than empty fullerenes during the association and the charge and proton transfer processes, The strong electron-donating character of endohedral metallofullerenes is due to their unique super-atom-like electronic structures. (C) 1997 by John Wiley & Sons, Ltd.

弯曲直径对多模光纤激光器输出性能的影响

大模场面积(LMA)多模光纤激光器的输出性能与光纤的弯曲程度有关。为研究两者之间的关系，在光纤不同弯曲直径下，对多模光纤激光器的输出性能进行了实验测量和理论计算。采用刀口法测量了不同弯曲直径下的激光光束质量因子M2，并对每种情况下光纤激光器的斜率效率进行了测量。光纤弯曲直径分别为285 mm,195 mm和130 mm时，多模光纤激光器光束质量因子M2为2.88,1.82和1.67，斜率效率为39%,35%和34%。另外，对于实验所采用的大模场面积多模光纤，理论计算了各模式损耗与光纤弯曲直径的关系。

Investigation of the spectroscopic properties of (Y0.92-xLa0.08Ndx)(2)O-3 transparent ceramics

The spectroscopic properties of (Y0.92-xLa0.08Ndx)(2)O-3 transparent ceramics were investigated. According to three intensity parameters (Omega(2),Omega(4),Omega(6)) fitted by the Judd-Ofelt theory, the spectroscopic quality parameter (X-Nd), branching ratio (beta(J,J')), and quantum efficiency (eta) of Nd3+ were determined. It was found that X-Nd of the host, owing to the additive La2O3, was decreased from 1.6 to 0.46; thus beta(J,11/2) was increased from 46% to 56.82%. A figure of merit of the specimens was discussed and compared with Nd:YAG transparent ceramic. (c) 2007 Optical Society of America.