香紫苏醇侧链的氧化降解

研究了高锰酸钾、高硼酸钠、高碘酸钠等对香紫苏醇侧链的氧化降解，并通过 IR，NMR，MS或元素分析等技术对氧化降解产物的结构进行了表征。     

掺铈纳米二氧化铅修饰电极色谱电化学用于单胺类神经递质的研究

研制了一种新型掺铈纳米二氧化铅修饰电极，用X射线衍射（XRD）和扫描隧道 显微镜（STM）进行了表征。该修饰电极对单胺类神经递质及其代谢产物有良好的 电催化作用，灵敏度高，稳定性和重现性好，将其作为电化学检测器与液相色谱和 微渗析技术联用，测定了帕金森氏症病人脑脊液中单胺类神经递质及其代谢产物的 含量。取得了满意的结果并初步探讨了帕金森氏症的致病机理。     

微渗析活体取样-NiHCF修饰电极色谱电化学检测的研究

研究了六氰合亚铁酸镍修饰电极对单胺类递质及其代谢产物的催化机理，首次以该 电极为色谱电化学检测器，对８种物质进行了分离测定。同时，将微渗析活体取样技术与高 效液相色谱一电化学检测联用测定了ＳＤ大鼠脑尾核处的单胺类递质及其代谢产物，并研究了 Ｃａ２＋浓度对脑中递质的影响，拓展了电分析化学在生物活体分析中的应用范围。     

高通量天然产物化学和毛细管核磁共振探头技术的应用

介绍了近几年为高通量药物筛选构建大型天然产物样品库的高通量天然产物化学,即多通道平行高效液相制备和平行液质联用分析技术;详细介绍了核磁共振新技术即体积小和质量灵敏度高的毛细管核磁共振探头技术,该探头技术的成功应用使得天然产物样品库中活性化合物的结构鉴定所需样品量降低到前所未有的微克级水平;展望了源于中药的天然产物作为小分子探针开展脑功能方面的化学基因组学研究。     

“树脂-捕获-释放”技术在有机合成中的应用

“树脂-捕获-释放”技术使用功能化聚合物清除剂选择性地吸附目标产物,液 相组合合成小分子化合物库。这一技术结合了固相和液相的优点,操作简便、快捷 ,反应容易控制,产物易分离,且产率高,纯度好。     

基于代谢组学和特征分子网络技术分析小鼠体内氧氟沙星的代谢产物

借助超高效液相色谱-四极杆串联飞行时间质谱（UHPLC-Q-TOF MS），结合代谢组学及特征分子网络（FBMN）技术，分析氧氟沙星在小鼠肌肉、结肠、肝脏、肾脏、回肠及内容物中的代谢产物。依据人类代谢组数据库（HMDB），利用代谢组学软件Progenesis QI鉴定出小鼠体内氧氟沙星的2种代谢产物，分别为N-氧化产物和培氟沙星；在FBMN技术下，依据可视化结果鉴定出5种代谢产物，其中两种与QI鉴定结果相同，另外3种分别为脱羧产物、脱羧后N-脱烷基化产物、脱氨后开环脱羧产物。采用所建立的方法快速分析了小鼠体内氧氟沙星的代谢产物。该方法具有快速、准确、无需标准品等特点，在其他代谢产物的分析方面具有广泛的应用前景。     

Thermodynamic and Equilibrium Composition of Using Iron Oxide as an Oxygen Carrier Nonflame Combustion Technology Analysis in

本文介绍了一种新的燃烧体系--熔融盐循环热载体无烟燃烧技术。这种燃烧体系杜绝环境污染气体NOx和CO2的排放，可以实现真正零排放的目标。计算了以Fe2O3作为氧载体的无烟燃烧体系的热力学参数。用最小吉布斯自由能原则，分析了Fe2O3与CH4的平衡组成。分析表明，如果要想在产物中产生高纯度的CH4完全氧化产物CO2和H2O，Fe2O3与CH4必须达到高摩尔比，如果Fe2O3的量不足，就会产生较多的部分氧化产物如CO，H2甚至C     

可溶导电聚苯胺的合成及其性能研究

以十二烷基苯磺酸（ＤＢＳＡ）为乳化剂和掺杂剂，采用水一油二相乳液聚合物方法对苯胺进行合成，制备出高溶解性和高电导率的ＰＡｎ，通过ｘ－射线，电镜分析和热重分析对产物的结构和性能进行了研究。结果表明，该法合成的导电性ＰＡｎ具有较高的特性粘度，溶解性，耐热性及结晶度，与非极性溶剂－表面活性剂－水三相体系聚合产物结果相似，透射电镜显示水乳液聚合产物呈较规则的纤维状取向排列。     

双戊烯合成萜马加成物的研究

以稀土金周氧化物（盐）为催化剂，催化工业双戊烯与顺丁烯二酸酐连续进行异构／Diels—Aldet反应，合成出萜烯／马来酸加成物；并用气相色谱法跟踪研究了反应的进程，及产物的组成与生产物的结构．结果表明本合成反应条件温和，反应易于控制，催化剂易于回收，产物得率比文献值高20个百分点，产物纯度大于90％，且产物性能能满足进一步合成的要求，为我国工业双成烯的应用开拓了新领域。     

氯铝酸室温离子液体中缩醛和缩酮反应

以取代硫酸等无机酸，实现清洁合成为目的，在1－烷基吡啶和1－甲基－3－ 烷基咪唑季胺盐与无水AlCl_3构成的室温离子液体为催化剂和反应介质中，尝试了 醛和酮与甲醇的缩合反应。醛与甲醇反应，产物以缩醛为主，酮与甲醇反应则有相 当量的Aldol缩合产物。依反应底物不同，可获得中至高的转化率和选择性。同时 ，一些产物因不溶于离子液体中而分层，便于产物分离。     

核糖核酸酶Sa表面水和尿素分子的分布和动力学行为的分子动力学模拟

利用分子动力学模拟研究了在不同尿素浓度下,核糖核酸酶Sa(RNase Sa)表面水和尿素分子的分布和动力学行为。 结果表明,尿素分子可与RNase Sa酶形成较强的相互作用,并取代其表面的水分子而富集在蛋白质表面。 尿素分子更倾向与RNase Sa酶的疏水残基作用,与RNase Sa酶主链形成氢键的能力更强。 尿素分子的平动和转动远远慢于水分子的平动和转动。 RNase Sa酶表面水分子的平动和转动随着尿素浓度增加而逐渐变慢,但RNase Sa酶表面尿素分子的动力学并不依赖于尿素浓度变化。 本研究中明晰的RNase Sa酶表面水和尿素分子分布和动力学有助于理解水和尿素分子对蛋白质稳定性的影响。     

The role of weak hydrogen-bonds on the formation of short-lived molecular associations

Weak molecular homo- and hetero-associations among some ethene derivatives and several common solvents are studied using (1)H NMR spectroscopy. In connection with the aromatic-solvent induced shifts which is a special case of molecular association between aromatic solvents and polar molecules a model for association was suggested that involves the interaction of the positive end of the solute dipole with the aromatic pi-electrons. This model met with certain difficulties. An alternative model for configuration of associated molecules that explains the literature results and the results obtained in this paper is presented. The model is based on interaction of protons of the acceptor molecules with the lone-pair electrons or pi-electrons of the donor molecules. The present model removes the difficulties met with the former model and extends the concept of aromatic-solvent induced shifts to include non-polar molecules besides polar ones. In all cases, the interaction of protons of acceptor molecules with lone-pair electrons of donor molecules gives rise to a deshielding effect, while interaction with aromatic pi-electrons leads to shielding.     

Cold Molecules: Preparation,Applications, and Challenges

Research with cold molecules has developed rapidly in recent years. There is now a variety of established methods for cooling molecules into the millikelvin range. Nevertheless, a focal point of current research is directed toward finding new ways to bring the temperature of molecules even closer to absolute zero. Samples of cold molecules offer not only important applications for high‐resolution spectroscopy, which benefit from the increased interaction time of slow molecules with electromagnetic radiation; they also promise access to an exotic regime of chemical reactivity, in which phenomena such as quantum tunneling and quantum resonances predominate. This review begins with an introduction to the methods by which cold molecules can be prepared, with special emphasis on Stark deceleration and traps. In addition to applications of cold molecules that have already been partially achieved, an important focus of the review concentrates on possible future applications, and both aspects are illustrated with selected examples.     

Impurity-stimulated heterogeneous nucleation of supercooled H2 clusters

The sizes and mass spectra of large (N=1900-13,700 molecules) cold (approximately 3.1 K) H2 clusters have been measured after scattering from CO molecules. Cluster-size measurements after between 2 and 8 collisions indicate that 7% of the H2 molecules are evaporated. This loss agrees with calculations for the number of H2 molecules evaporated by the heat released in the transition from an initial liquid state to a final solid state. Even though heterogeneous nucleation is initiated after only a few collisions with CO molecules, the mass spectra show that additional captured CO molecules coagulate to form large CO clusters with up to n=11 molecules, suggesting that the outer layer is sufficiently liquidlike to facilitate mobility of the CO molecules. Since the calculated H2 cluster temperature (approximately 3.1 K) is below the superfluid transition temperature predicted for pH2 with density between 40% and 80% of the triple-point density, a shell-like region of low density near the cluster surface can be expected to be superfluid.     

Cold collisions of complex polyatomic molecules

We introduce a method for classical trajectory calculations to simulate collisions between atoms and large rigid asymmetric-top molecules. We investigate the formation of molecule-helium complexes in buffer-gas cooling experiments at a temperature of 6.5 K for molecules as large as naphthalene. Our calculations show that the mean lifetime of the naphthalene-helium quasi-bound collision complex is not long enough for the formation of stable clusters under the experimental conditions. Our results suggest that it may be possible to improve the efficiency of the production of cold molecules in buffer-gas cooling experiments by increasing the density of helium. In addition, we find that the shape of molecules is important for the collision dynamics when the vibrational motion of molecules is frozen. For some molecules, it is even more crucial than the number of accessible degrees of freedom. This indicates that by selecting molecules with suitable shape for buffer-gas cooling, it may be possible to cool molecules with a very large number of degrees of freedom.     

Quantitative Structure-Property Relationship: XVII. Properties of Branched Hydrocarbon Molecules

A simple approach to estimating properties of branched molecules is suggested: A property of any nonlinear molecule is considered as a sum of the property of the corresponding linear molecule and correction "for branching,"] determined by the interaction of atoms of the substituting group with atoms of the main chain. The potential of this approach is demonstrated by the calculation of the melting points, heat capacities, entropies, and enthalpies and free energies of formation for 117 saturated hydrocarbon molecules, including all the linear C₁-C₂₀ molecules and branched C₄-C₁₀ molecules with methyl substituents; also the heats of vaporization are calculated for 72 molecules including all linear C₁-C₂₀ molecules and branched C₄-C₉ molecules with methyl substituents. The accuracy of all the estimates is high. When the linear contribution is taken into account more accurately, with correction for nonlinear variation of properties of linear molecules, it becomes possible to highly accurately in estimate various properties of both linear and branched molecules, using the molecular connectivity indices.     

HIGH RESOLUTION SCINTILLATION SPECTRA OBTAINED WITH NANOSECOND PULSES OF 3 MeV ELECTRONS*

In studies involving an energy transfer process it is important to have definite knowledge of the excited state of the solute which is responsible for the emitted fluorescence that is measured. When solutions with low solute concentration are irradiated with ionizing particles, the initial excitations are produced in the solvent molecules (excited molecules or ions). The excited solvent molecules and ions can transfer energy to the solute producing excited solute molecules. The measured scintillations are the result of the return of the solute molecules to the ground state.     

Energetics of low-molecular-mass products of mechanical fracture of poly(methyl methacrylate)

It is experimentally revealed that monomer and water molecules released during the fracture of PMMA have a bimodal velocity distribution. The first distribution peak for the monomer corresponds to energetic (hot) MMA molecules (0.13–0.70 eV), and the second peak is attributed to MMA molecules bearing a low energy (0.016–0.060 eV). On the basis of the results of earlier theoretical studies of the mechanically induced polymer-chain scission, it was concluded that the energetic monomer molecules are produced immediately in the event of mechanical chain rupture and are nonthermal in nature. In the bimodal velocity distribution of occluded water molecules desorbed from a subsonic crack, the first and the second peaks are attributed to “hot” and “cold” molecules with translational temperatures of 605 ± 180 K and 53 ± 5 K, respectively. A possible mechanism of the mechanically induced desorption of occluded water is discussed. The mechanodesorption of water molecules is due to the portion of vibrational energy transferred to side methyl carboxylate groups that retain water molecules by the unloading-wave front traveling along the main chain from a macromolecule scission site. Along with hot water molecules, a considerable amount of hot free hydroxyls were detected. The mechanism of formation of the latter species is associated with the double-well structure of the hydrogen bond potential and similar to the mechanism of mechanodesorption of hot molecules of water.     

Molecular Dynamics Simulations of the First Steps of the Formation of Polysiloxane Layers at a Zinc Oxide Surface

Three different dissolved silane molecules adsorbed at a polar ZnO surface (000&1macr;) are studied by means of constant temperature molecular dynamics simulations. The adsorbed single silane molecules exhibit a different behavior depending on the chemical nature of their tail. For octyltrihydroxysilane molecules with their rather unpolar tail an orthogonal orientation at the polar metal oxide surface is statistically favored with all three polar hydroxide groups of the head being in contact with the polar ZnO surface and the unpolar tail remaining in the isopropanol phase. On the contrary, due to their highly polar tail, aminopropyltrihydroxysilane molecules show a more or less parallel orientation at the surface. Apart from some minor fluctuations two hydroxide groups as well as the amino group of the tail are in contact with the surface. The behavior of the thiolpropyltrihydroxysilane molecules is somehow located in between resulting in parallel as well as orthogonal orientations of the molecule at the surface. Though many of the results obtained for single adsorbed silane molecules can also be transferred to adsorbed silane molecules within whole layers a remarkable difference appears: Now even for aminopropyltrihydroxysilane molecules a mixture of parallel and orthogonal alignment of the molecules can be observed whereas some of the octyltrihydroxysilane molecules also show a parallel orientation.