N—乙基—α—甲基—间（三氟甲基）苯乙胺的合成

本文报道了一种新的简便的合成Ｎ－乙基α－甲基－间苯乙胺的方法。方法以三氟甲苯为原料，经氯甲基化，Ｇｉｇｎａｒｄ及Ｌｅｕｃｋａｒｔ反应后得目标物，具有原料价廉易得，毒性较小，反应条件温和，工艺流程较短等特点。     

About compensation effect by thermal decomposition of some catalyst precursors

Summary In order to obtain catalysts, the thermal decomposition of the precursors is a compulsory step. However, kinetic analysis of the decomposition data obtained under non-isothermal conditions lead very seldom to the intimate reaction mechanism. There is also a lack of information because in non-isothermal kinetics, the compensation effect, is rather a rule and unfortunately a source of debate. In order to discriminate between these processes, and the influence of conversion, respectively temperature on the reaction rate, the NPK (non-parametric kinetic - Sempere and Nomen) method was used. This method is based on the singular value decomposition algorithm (SVD) applied on the matrix of reaction rate at corresponding conversion and temperature. This method allows a less speculative determination of the conversion functions and of the kinetic parameters.     

Parallel solution combustion synthesis for combinatorial materials studies

A parallel solution combustion synthesis technique was developed for combinatorial materials studies. The vigorous combustion reactions were successfully limited in the microreactors by using a substrate-net-mask microreactor system and the lowest adoptable furnace temperature. Using this technique, a luminescent materials library of Y3Al5O12/Tb(chi) was synthesized with the aid of an ink-jet delivery system. Structure and luminescence characterizations were implemented using X-ray diffraction and UV/X-ray spectroscopies, respectively. The results show that this technique is reliable and applicable to combinatorial study of powder materials with high synthesis temperature.     

Solid state a.c. conductivity and FT-IR spectral analyses for the conflicting effects of proton mobility and association in some azophenol derivatives of cyclic phosphazene

Variable strength H-bonding affects the mobility and so electric conduction of protons differently. Also, variable extent mesomerism modifies electric conduction with varying dielectric features. Both these molecular modifiers are properly cited using azophenol derivatives as model compounds for discussion of their consequences in the varying features of electric conduction. The electric permittivity shows low-frequency dispersion characteristic of ionic conduction over mobile charge carries; the mobility shifts at a critical temperature T _c, being structure dependent. The frequency-dependent Z′′-Z′ layout changes with temperature from linear at low temperatures to semicircular above T _c within a frame of temperature-sensitive dipole-ionic mediated conduction. The a.c. conductivity, σ_ac, increases with frequency and temperature and becomes frequency insensitive, like d.c. conductivity, σ_dc, above the T _c because of the escalating contribution from the d.c. conduction. The mesomeric structure seems to prompt a dipole-based electric conduction of high relaxation energy over the strongly associated phenolic protons that may be thermally activated above the T _c into a much lower relaxation energy protonic conduction of up to two orders higher conductivity. The protonic conduction emerges at a T _c that falls with a drop in the relaxation energy following a similar order of increasing proton mobility and mesomerism in the azophenol derivatives: azocatechol>azoquinol>azoresorcinol. On the molecular level, variable temperature infrared spectroscopy reveals higher proton mobility and mesomerism for the azocatechol derivative that demonstrates its higher protonic conductivity at lower T _c and relaxation energy, compared to the azoquinol and azoresorcinol derivatives. This is well verified in the light of conflicting intramolecular H-bonding that assists the proton mobility in azocatechol whereas it associates the protons in azoresorcinol more than in azoquinol. Electronic Publication     

Microwave-assisted extraction of zearalenone from wheat and corn

A microwave-assisted extraction (MAE) method has been developed for determination of zearalenone in wheat and corn by LC-MS with an atmospheric pressure chemical ionization interface (APCI). Matrix effects were minimized by use of matrix-matched standard curves for quantification of the analyte. The limit of quantification (LOQ) of the method was 30 ng g(-1) in wheat and 20 ng g(-1) in corn. The rapid LC-MS method enabled analysis of the extracts without clean-up, thereby reducing analyte losses, the time required for the analytical procedure, and costs. A factorial design approach was used to examine the effect on extraction efficiency of the main extraction conditions - time, temperature, and solvent. On the basis of results from statistical assessment extraction was performed with 1:1 (v/v) methanol-acetonitrile at 80 degrees C for 5 min. When these extraction conditions were applied to a wheat sample from a recently conducted international proficiency test, 92% (103 ng g(-1)) of the assigned zearalenone concentration (112 ng g(-1)) in the test material was obtained. This result was within the uncertainty (u) range of the assigned value of the test material (u=+/-15.8 ng g(-1), alpha=0.05) thereby demonstrating the accuracy of the method was sufficient. The precision of the whole method was also confirmed to be adequate, because the observed relative standard deviation (RSD) of 12% (n=10) also fulfils the quality criteria recommended by European guidelines for in-house method validation.     

Mathematical studies of Kekulé structures

The perfect matching vector and forcing and the Kekulé-vector of cata-benzenoids are defined. Two theorems are given which set the sufficient and necessary conditions for HKZ-vector (Harary et al. J Math Chem 6:295, 1991) and Kekulé-vector in cata-benzenoids. Additional two theorems are obtained which give sharp bounds for the modules of HKZ- and Kekulé vectors. Dedicated to Professor Tadeusz Marek Krygowski on the happy occasion of his 70th birthday.     

High-resolution Hadamard transform microscope fluorescence imaging: quantifying the DNA content in single cells

This study presents a novel miniaturized Hadamard transform fluorescence imaging microscope, by combining a conventional fluorescence microscope with Hadamard transform multiplexing encoding using a one-dimensional movable mask to realize spatial resolution and a linear CCD for multichannel detection. The microscope can provide high-resolution automatically-generated 0–255 gray level HT images for morphological analysis and visualization of a single cell, and normalized HT images for cellular quantitative measurements. The microscopes imaging capability was applied to measure the DNA content in human lymphocyte, chicken erythrocyte and eel erythrocyte, and a comparative study was performed. The results show that the calibrated DNA content in a chicken erythrocyte is 2.32 pg when human lymphocyte is used as the standard, and eel erythrocyte may be a potentially reliable and novel standard for determining DNA contents in other species because it has a stable DNA value of 2.06 pg, with a CV of 4.3% when 20 eel erythrocytes are measured. The results also demonstrate that the HT imaging microscope should be valuable in the fields of medicine and cell biology.     

Chemische Vitamin D<Subscript>3</Subscript>-Bestimmung in Lebertran

The different aspects of Vitamin D₃ determination and the data reported in the literature are discussed. The spectrophotometric determination of Vitamin D₃ in cod-liver oil is carried out after the alkaline saponification, extraction of unsaponified parts, precipitation of accompanying sterols and the column- and thin-layer chromatographic purification and separation of vitamin D₃ on 40 cm plates from other vitamins. The dyestuff α-naphtholbenzein is suited well as standard substance for the better location and identification of vitamin D₃ zone on the thin-layer plate. The results obtained from the chemical method were checked through the simultaneous biological determination.     

Inclusion-dependent mechanism of modification of cyclodextrins with heterocycles

Mono(6-deoxy-dimethylpyridinium)-β-cyclodextrins have been synthesized in reaction of mono (p-toluenesulfonyl) derivative of β cyclodextrin with the appropriate lutidine under microwave irradiation and conventional conditions. The results indicate that the mechanism consists of inclusion complex formation.     

Analysis of urban dust (PM<Subscript>2</Subscript>/PM<Subscript>10-2</Subscript>) in Daejeon city by instrumental neutron activation analysis

Summary As part of an air pollution monitoring study, airborne particulate matter (PM₂/PM_10-2) samples were collected from 2000 to 2003 at two sampling sites in an urban region, Daejeon, the middle of Korea. Mass concentrations of both fine and coarse fractions and that of the black carbon in the fine particles were measured using the Gent stacked filter unit sampler and the smoke stain reflectometer, respectively. In the collected samples the concentrations of 24 elements were analyzed using instrumental neutron activation analysis. Monitored data were investigated for their temporal trends under different environmental conditions and their seasonal correlation patterns. Crustal enrichment factors were also estimated to establish the contribution between anthropogenic and crustal origin. Patterns for airborne particle matter (APM) and elemental concentrations, seasonal variation of some marker elements were investigated. The results can be applied for the investigation of further air pollution sources and for the evaluation of air quality.