GC-MS监测生活饮用水输配水管材及防护材料中溶出的挥发性有机物

我国的生活饮用水行业中,目前常使用的管材分为金属类管材和非金属类管材两种。由于金属类管材本身的化学特性,行业内必须在此类管材的内壁上进行防腐处理,通常采用一些高分子防腐涂料。可用于给水行业的涂料品种繁多,涂料质量好坏直接影响到水质。我们针对一些常用产品作了浸泡试验,用吹扫捕集-GC-MS方法对水中溶出的可挥发性有机物进行了检测,发现一些产品在水中溶出了大量的甲苯、乙苯、二甲苯、甲乙苯等苯系物,且浸泡30d后仍有溶出物。这些物质长期存在会导致人体中枢神经系统紊乱,严重危害人体健康。行业内关于水源水中此类有机物污染的监测比较充分,而对于防护涂料可能污染水质的状况并未引起足够重视。     

Shortcut method for evaluation and design of a hybrid process for enantioseparations

Hybrid processes for enantioseparations have a considerable potential for reducing investment and operational costs. An example is the combination of simulated moving bed (SMB) chromatography and selective crystallisation. However, the design of integrated processes is a difficult task. A shortcut method is presented that can serve as a tool for design and estimation of the potential of such processes. The approach requires only limited experimental data and thus allows for systematic parameter studies. The method is based on the determination of the purity-performance characteristic of the SMB process and rigorous application of mass balances. The use of relative mass fluxes allows derivation of simple algebraic expressions for essential process parameters. The significant potential of combining SMB and crystallisation is demonstrated for the example of the separation of mandelic acid enantiomers.     

CCSD(T) expectation value calculations of first-order properties

An expectation value approach to calculations of first-order properties using the non-iterative, triple-excitation amplitudes in the coupled cluster wave function is exploited. Three methods are suggested and analysed using the many body perturbation theory (MBPT) expansion arguments. The first method, in which non-iterative triple-excitation amplitudes are used in the expression for the expectation values, makes the wave function accurate through the second order of MBPT. In the second method, which is an extension of the first, effects of triple-excitation amplitudes are coupled with single- and double-excitation amplitudes. The correlated density matrix equivalent through the fourth order to that obtained when CCSDT-la amplitudes are used is employed in the third method. The suggested methods are tested on dipole moment and polarizability calculations for several diatomic closed-shell molecules and are compared to other related approaches. Received: 15 May 1997 / Accepted: 5 June 1997     

Forbidden electric quadrupole transitions between even OIII levels

The relativistic CI method is used to determine transition probabilities for electric quadrupole transitions between the 1s ² 2s ² 2p ² (³ P ₀,³ P ₂,¹ D ₂) and 1s ² 2p ^{4 3} P ₂ even levels of OIII. The variation of the results with the number of configurations used is discussed, both for the Coulomb and the Babushkin (length) gauge.     

A relativistic CI study on OIII: wavefunctions,excitation energies and transition probabilities

The relativistic CI method is used to determine N-electron wavefunctions for the 1s ² 2s ² 2p ² (³ P ₀,³ P ₂,¹ D ₂), 1s ² 2p ^{4 3} P ₂ even levels, and the 1s ²2s2p ³ (³ D ₁,³ P ₁,³ S ₁,¹ P ₁), 1s ²2s ²2p3s (³ P ₁ and¹ P ₁), 1s ²2s ²2p3d (³ D ₁,³ P ₁,¹ P ₁)J=1 OIII levels. Excitation energies and emission probabilities between these levels are reported in the electric dipole approximation, both for the Coulomb and the Babushkin gauges.ns, p,np,nd- andnd (n17) numerical basis functions have been used for the construction of CSF's entering the CI expansion for the ASF's of these levels. Radiative matrix elements of the type calculated here within the framework of the relativistic CI method, may be used in laser assisted spectroscopic studies of atoms and ions.     

A DFT and direct MO dynamics study on the structures and electronic states of phenyl-capped terthiophene

The structures and electronic states of phenyl-capped terthiophene (denoted by P3T) and the ionic species of P3T have been investigated by means of density functional theory (DFT) and direct MO dynamics calculations. P3T is one of the high-performance molecular devices, which has been utilized as a semi-conductor. The calculations indicated that the neutral P3T has a non-planar structure whose the phenyl rings in both ends of thiophene chain are largely deviated from the molecular plane. The cation and anion radicals, dication and dianion were considered as its ionic states. The structure for cation radical of P3T is close to more planar than that of neutral P3T. The structures for anion radical, dication and dianion take a pure planar structure. The first excitation energy of neutral P3T is calculated to be 2.90 eV at the TD-B3LYP/6-31G(d)//B3LYP/6-311+G(d) level, while the P3T cation and anion radicals have lower excitation energies (1.22 and 1.10 eV, respectively). The direct MO dynamics calculation showed that neutral, cation and anion hold near planar structure at 300 K. On the other hand, oligothiophene (n = 5) and its ionic species are strongly deformed from the planar structure, and thiophene rings in both ends of chain rotate rapidly by thermal activation. The mechanism of the electron conductivity in P3T was discussed on the basis of theoretical results.     

meso－四（3，5－二溴－4－羟基苯基）卟啉［T（DBHP）P］二阶导数光度法同时测定废水中锌和铅的研究

本文研究了ｍｅｓｏ－四（３，５－二溴－４－羟基苯基）卟啉与铅，锌显色反应的二阶导数光谱行为，建立了同时测定电镀废水中锌和铅的二阶导数光度法。在硼砂－氢氧化钠碱性介质中，沸水浴上加热３ｍｉｎ，锌、铅的显色反应即可定量完成。比耳定律范围分别为：０～１０μｇ／２５ｍＬＺｎ￣（２＋），０～１０μｇ／２５ｍＬＰｂ￣（２＋）；检出限为：ｃ＿（Ｌ、Ｚｎ）￣（２＋）＝５．６ｎｇ／ｍＬ，ｃ＿（ＬＰｂ）￣（２＋）＝４．０ｎｇ／ｍＬ。     

Problems with the ζ-function method

The -function method for evaluating effective actions is applied to an operator containing a potential localized on two parallel planes. This operator is characterized by a continuous spectrum and broken translation invariance. In this case, the -method leads to a divergent volume factor independent of the physical parameters. In a suitable regularization scheme, only the next to leading order term reproduces a physically interesting result.     

番红花红T与表面活性剂的作用及其在标记DNA中的应用

对阳离子染料番红花红Ｔ（ＳＴ）在阴离子表面活性剂存在时的溶液状态的吸收光谱和荧光光谱进行了研究。结果表明，低浓度阴离子表面活性剂与ＳＴ形成缔合物，导致ＳＴ的吸收与荧光强度降低；增大表面活性剂的浓度，其分子胶束前预聚集促使染料形成非荧光二聚体，导致荧光急剧猝灭，吸收光谱出现新的特征吸收峰；当表面活性剂浓度大于临界胶束浓度（ＣＭＣ）时，染料二聚体离解，ＳＴ单体增溶于胶团中形成新的高量子产率荧光体。本文