无相移滤波技术用于分析化学信号处理

把无相移滤波技术引入了分析化学信号处理领域.其方法为先将输入序列按顺序滤波,然后将所得结果逆转后反向通过滤波器,再将所得结果逆转后输出.通过对色谱信号的实验研究表明,与普通的数字滤波方法相比较,无相移滤波不但具有普通数字滤波的优点,而且不会产生滤波前后的相位偏移,具有良好的应用前景,尤其对于需要准确计算保留时间的场合,用此预处理方法非常适合.     

对映异构体的高效毛细管电泳分离与测定

高效毛细管电泳是８０年代发展起来的一种高效、快速的新型分离技术，在对映异构体分离方面有着广泛的应用前景，本文介绍了这一新型分离技术用于对映体分离的基本原理，并列举了一些对映异构体分离的实例。     

In/HZSM-5催化剂上CH4选择还原NO的研究: 反应条件对催化剂性能的影响

用浸渍法制备的In/HZSM-5催化剂在甲烷还原一氧化氮反应中显示了很高的活性,500℃时,氧化氮的转化率可达100%.过量氧气的存在并没有对催化剂的活性产生很大的影响,这可能与In/HZSM-5催化剂上甲烷选择还原一氧化氮的反应机理有关.随着反应气体空速的增大,氧化氮的转化率缓慢下降,同时,甲烷的转化率也缓慢下降.这说明还原剂甲烷的适度活化在本反应中起着关键作用.     

Simultaneous analysis of twenty-one glucocorticoids in equine plasma by liquid chromatography/tandem mass spectrometry

A method for the simultaneous separation, identification, quantification and confirmation of the presence of 21 glucocorticoids (GCC) in equine plasma by liquid chromatography coupled with triple stage quadrupole tandem mass spectrometry (LC/TSQ-MS/MS) is described. Plasma sample augmented with the 21 GCC was extracted with methyl tert-butyl ether (MTBE) and analyzed by positive electrospray ionization. Desoxymetasone or dichlorisone acetate was used as the internal standard (IS). Quantification was performed by IS calibration. For each drug, one major product ion was chosen and used for screening for that drug. Analyte confirmation was performed by using the three most intense product ions formed from the precursor ion and the corresponding mass ratios. The recovery of the 21 GCC when spiked into blank plasma at 5 ng/mL was 45-200% with coefficient of variation (CV) from 0.3-18%. The limit of detection (LOD) and that of quantification (LOQ) for most of the analytes were 50-100 pg/mL and 1 ng/mL, respectively, whereas that of confirmation (LOC) was 100-300 pg/mL depending on the analyte. Intra- and inter-day precisions expressed as CV for quantification of 1 and 10 ng/mL was 1.0-17%, and 0.51-19%, respectively, and the accuracy was from 84-110%. The linear concentration range for quantification was 0.1-100 ng/mL (r(2) > 0.997). Estimated measurement uncertainty was from 11-37%. This study was undertaken to develop a method for simultaneous screening, identification, quantification and confirmation of these agents in post-race equine plasma samples. The method has been successfully applied to screening of a large number of plasma samples obtained from racehorses in competition and in pharmacokinetic studies of dexamethasone in the horse and concurrent changes in endogenous GCC, hydrocortisone and cortisone. The method is simple, sensitive, selective and reliably reproducible.     

Heat flux and the calorimetric-respirometric ratio as measures of catabolic flux in mammalian cells

It is advocated that cellular heat flow rate (Ø = dQ/dt, where Q is heat) be expressed as an intensive quantity specific to cell size (X) and termed heat flux (J_Ø/X). It has been the practice to cite such data on a ‘per cell’ basis, but it would be preferable to use biomass (cellular volume or mass). This quantity is shown to be a measure of metabolic activity and, more accurately, catabolic rate coupled to the demand for ATP in anabolic processes and work in the cell. Recent developments in flow microcalorimetry and dielectric spectroscopy reveal that heat flux can be measured on-line, with the potential of industrial use as a control variable in the growth of hybridoma and genetically engineered cells. This is because the enthalpy change of growth can be regarded as a unique kind of stoichiometric coefficient directly related to the mass coefficients in the growth reaction. This can be verified by an enthalpy balance comparing data for material fluxes of catabolites with the value for heat flux. Information revealed by the stoichiometric growth equation can be used to improve medium design.

The ratio of heat flux to oxygen consumption (flux) is known as the calorimetric-respirometric (CR) ratio. It detects anaerobic processes when the value is more negative than −450 (±5%) kJ mol⁻¹ O₂. These processes are found in cells growing under fully aerobic conditions, because glycolysis provides biosynthetic precursors with lactate as the byproduct. It is suggested that the CR ratio would be a powerful on-line control variable for the growth of animal cells in bioreactors.     

The application of isotope dilution thermal ionization mass spectrometry to traceability of chemical measurement and interlaboratory comparisons

In this work, the method of isotope dilution thermal ionization mass spectrometry able to trace to SI was developed to accurately measure trace amount of Cd, Pb, Zn and Cu in sediment, rice, wine, and human serum samples for interlaboratory comparisons. The research focuses on how to apply the primary method correctly, uncertainty evaluation of measurement results, and how to achieve the meaning of traceability to SI by using ID-TIMS. As a result, the measurement results of Cu and Zn in the human serum 1 and 2 with 0.94, 0.83 and 0.49% combined uncertainty, respectively, were accepted by EC-JRC-IRMM as the certified values of the serum samples. The measurement results of Cd and Pb in CCQM-K13 and CCQM-K24 with 3.96, 1.62 and 1.03% combined uncertainty, respectively, are within the degrees of the equivalence. These comparisons at the highest level of measurement are proof that traceability of chemical measurement can be achieved as the traceability chain of ID-TIMS established in this work was used.     

Synthesis of titania-supported platinum catalyst: the effect of pH on morphology control and valence state during photodeposition

Solid-supported metal catalysts have been widely used in industrial processes. The morphology of coated metal on the support is usually an important factor affecting the efficiency of the catalyst. In this study, a photocatalytic process is utilized to control the morphology of platinum particles deposited on titania (Degussa P-25). More specifically, the effect of pH on the morphology and the valence state of platinum nanoparticles was systemically investigated. It is found that, via a simple pH-controlled process, various states of platinum (Pt0, PtIIO, or PtIVO2) can be deposited onto the support directly at will. In this paper, the mechanism of morphology control and the key influencing factors at different pH regimes will be discussed. Followed by photodeposition, a H2 thermal treatment process was employed to convert the oxides into metal platinum with narrow size distribution and even coverage on the supporting titania. Various techniques such as transmission electron microscopy, high-resolution transmission electron microscopy, energy-dispersive analysis of X-rays, and X-ray photoelectron spectroscopy were employed to characterize the prepared titania-supported platinum particles.     

On the non-symmetric planar aligned NLC cell

The planar aligned nematic liquid crystal cell with different anchoring for the two substrates (i.e. a non-symmetric NLC cell) is investigated by an analytical method. We deduce the basic equations and the boundary conditions of the tilt angle θ of the LC director. Expressions for threshold and saturation magnetic field are obtained, and numerical results of these two quantities with variation in anchoring parameters of the two substrates are given. A symmetry breaking parameter Δ is introduced and the relations between Δ and applied field, as well as the two sets of anchoring parameters are discussed in detail. A feasible experimental plan for measurement of anchoring strengths of a series of different substrates is proposed.     

中国芦荟化学成分研究——芦荟大黄素的分离与结构鉴定

首次报道湛江地区徐闻县打银村产的芦荟主要有效成分，并通过化学和光谱分析（MS，^1H-NMR,IR,UV)鉴定其结构为芦荟大黄素（Aloe-emodin)。     

In situ analysis of interfacial reactions between negative MCMB,lithium electrodes,and gel polymer electrolyte

The interfacial properties of mesocarbon-microbeads (MCMB) and lithium electrodes during charge process in poly (vinylidenefluoride-co-hexafluoropropylene)-based gel electrolyte were investigated by in situ Raman microscopy, in situ Fourier transform-infrared (FTIR) spectroscopic methods, and charge–discharge, electrochemical impedance spectroscopy techniques. For MCMB electrode, the series phase transitions from initial formation of the dilute stage 1 graphite intercalation compound (GIC) to a stage 4 GIC, then through a stage 3 to stage 2, and finally to stage 1 GIC was proved by in situ Raman spectroscopic measurement. The formation of solid electrolyte interface (SEI) films formed on MCMB and metal lithium electrode was studied by in situ reflectance FTIR spectroscopic method. At MCMB electrode surface, the solvent (mostly ethylene carbonate) decomposed during charging process and ROCO₂Li may be the product. ROCO₂Li, ROLi, and Li₂CO₃ were the main composites of SEI film formed on lithium electrode, not on electrodeposited lithium electrode or lithium foil electrode.