Decomposition of Transformer Oil Under Ultrasonic Irradiation During Degassing Process

In the degassing process of transformer oil with ultrasonic waves ,decompostition of the oil was observed.Light hydrocarbons,including methane,ethane,ethylene ,aceylene,propane etc,were found to be released continuously from the oil into headspace within a closed vial placed in an ultrasonic field ,The gases came from decomposition of hydrocarbon molecules under cavitation effect.     

LiCl急冷过程中结构变化研究的一种几何学方法

计算了900 K、698 K、498 K和298 K温度下共4800个Voronoi多面体并对它们进行了统计分析. 计算表明: 在玻璃态转变温度区间, Voronoi多面体的统计分布有明显的变化。在以阳离子为中心的Voronoi多面体中, 在298 K时,四面体、五面体和六面体占总数的80%以上。     

A new C21-steroidal glycoside from Cynanchum stauntonii

A new C21-steroidal glycoside with two known compounds were isolated from the root of Cynanchum Stauntonii.Based on thespectral analysis,including MS,1H NMR,13C NMR,DEPT,1H-1H COSY,13C-1H COSY,HMQC and HMBC,their chemicalstructures were determinated as glaucogenin-C 3-O-a-L-cymaropyranosyl-(1→4)-b-D-digitoxopyranosyl-(1→4)-β-D-canaropyranoside(1),stigmasterol(2)and ursolic acid(3).     

醋酸十二铵的吸附和SiO2悬浮液的稳定性

（1）测定了醋酸十二烷基铵（DAA）在CAB－O－SIL上的吸附，其等温线属双平台或LS型[1－3，5]；（2）NaCl的存在使DAA的吸附增加．但不影响其低浓度下第一平台的吸附量；HCl的存在则在全浓度范围内抑制了DAA的吸附，（3）测定了CAB－O－SIL颗粒在上述各溶液中的悬浮液的稳定性；（4）根据表面形成小胶团的吸附理论（即二步模型产）[2，3，5，]，并借助电导跟踪溶液中发生的变化，满意地解释了吸附和聚沉的实验结果．     

氨基酚异构体的离子对反相液相色谱分析的研究

本文研究了离子对反相液相色谱分析氨基酚异构体的可能性、影响因素和色谱条件，发现以含４×１０－８ｍｏｌ／Ｌ四丁基碘化铵、０．１８４ｍｏｌ／Ｌ醋酸钠的甲醇水溶液（２３：７７）作为流动相，ＯＤＳ为固定相时可以实现氨基酚异构体的良好分离。     

Liquid–solid disk extraction followed by supercritical fluid elution and gas chromatography of phenols from water

A method combining the techniques of liquid – solid disk extraction (LSDE) and supercritical fluid elution (SFE) has been developed for the phenols regulated by the Clean Water Act. LSDE uses a disk or membrane made of polytetrafluoroethylene (PTFE) fibrils impregnated with small particles, e.g. styrene divinylbenzene (SDB) resin, to extract phenols from water. After disk extraction the retained analytes are eluted from the disk using SFE. SFE is used as an alternative to liquid solvent elution with an organic solvent. Analytes are separated, identified, and quantified using gas chromatography – ion trap detector mass spectrometry (GC-ITDMS). The method is capable of sub parts per billion detection limits, and precision of 5–28% RSD. Evaluation of various disks or membranes, such as C₁₈-silica disks, SDB disks, and ion exchange membranes, has also been performed for the extraction of phenols from water. The results obtained from the in-situ aqueous acetylation of phenols and extraction of their acetates are quantitative. The utilization of LSDE and SFE techniques has proven to be a more effective approach than liquid – liquid extraction in minimizing air pollution and solvent waste.     

Exact electronic properties in the classically forbidden region of a metal surface

We derive exact properties of the inhomogeneous electron gas in the asymptotic classically forbidden region at a metal–vacuum interface within the framework of local effective potential energy theory. We derive a new expression for the asymptotic structure of the Kohn–Sham density functional theory (KS‐DFT) exchange‐correlation potential energy v_xc(r) in terms of the irreducible electron self‐energy. We also derive the exact asymptotic structure of the orbitals, density, the Dirac density matrix, the kinetic energy density, and KS exchange energy density. We further obtain the exact expression for the Fermi hole and demonstrate its structure in this asymptotic limit. The exchange‐correlation potential energy is derived to be v_xc(z → ∞) = ?α_KS,xc/z, and its exchange and correlation components to be v_x(z → ∞) = ?α_KS,x/z and v_c(z → ∞) = ?α_KS,c/z, respectively. The analytical expressions for the coefficients α_KS,xc and α_KS,x show them to be dependent on the bulk‐metal Wigner–Seitz radius and the barrier height at the surface. The coefficient α_KS,c = 1/4 is determined in the plasmon‐pole approximation and is independent of these metal parameters. Thus, the asymptotic structure of v_xc(z) in the vacuum region is image‐potential‐like but not the commonly accepted one of ?1/4z. Furthermore, this structure depends on the properties of the metal. Additionally, an analysis of these results via quantal density functional theory (Q‐DFT) shows that both the Pauli W_x(z → ∞) and lowest‐order correlation‐kinetic W(z → ∞) components of the exchange potential energy v_x(z → ∞), and the Coulomb W_c(z → ∞) and higher‐order correlation‐kinetic components of the correlation potential energy v_c(z → ∞), all contribute terms of O(1/z) to the structure. Hence correlations attributable to the Pauli exclusion principle, Coulomb repulsion, and correlation‐kinetic effects all contribute to the asymptotic structure of the effective potential energy at a metal surface. The relevance of the results derived to the theory of image states and to KS‐DFT is also discussed. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

Physical/chemical separations in the break-up of highly charged droplets from electrosprays

Highly-charged droplets, as formed by an electrospray process, are known to undergo asymmetric fission to form smaller droplets. We have observed a chemical and physical separation phenomenon that occurs in the droplet break-up process and is related to a compound's surface activity in solution. Two experimental approaches demonstrated that the smaller satellite droplets and the progeny droplets generated by the spray formation and asymmetric fission processes to be surfactant-enriched. These smaller droplets were also effectively separated from the larger primary and residual droplets because of their smaller inertia and high surface charge density, and a region attributed to the initially formed smaller satellite droplets was found to be strikingly confined in a narrow periphery region of the electrospray. The phenomenon may have utility for chemical separations and have significant implications for the sensitivity and selectivity of electrospray ionization-mass spectrometry.