Statistical analysis of microscale gas flows and stock price changes

First, recent studies on the information preservation (IP) method, a particle approach for low-speed micro-scale gas flows, are reviewed. The IP method was validated for benchmark issues such as Couette, Poiseuille and Rayleigh flows, compared well with measured data for typical internal flows through micro-channels and external flows past micro flat plates, and combined with the Navier-Stokes equations to be a hybrid scheme for subsonic, rarefied gas flows. Second, the focus is moved to the microscopic characteristic of China stock market, particularly the price correlation between stock deals. A very interesting phenomenon was found that showed a reverse transition behaviour between two neighbouring price changes. This behaviour significantly differs from the transition rules for atomic and molecular energy levels, and it is very helpful to understand the essential difference between stock markets and nature.

Analysis of sulfur-containing compounds in crude oils by comprehensive two-dimensional gas chromatography with sulfur chemiluminescence detection

This paper reports an analytical method for separating, identifying, and quantifying sulfur-containing compounds in crude oil fraction (IBP-360degreesC) samples based on comprehensive two-dimensional gas chromatography coupled with a sulfur chemiluminescence detector. Various sulfur-containing compounds and their groups were analyzed with one direct injection. 3620 peaks were detected including 1722 thiols/thioethers/ disulfides/1-ring thiophenes, 953 benzothiophenes, 704 dibenzothiophenes, and 241 benzonaphthothiophenes. The target sulfur compounds and their groups were identified based on the group separation feature and structured retention of comprehensive two-dimensional gas chromatography as well as standard substances. The quantitative analysis of major sulfur-containing compounds and total sulfur was based on the linear response of the sulfur chemiluminescence detector using the internal standard method. The sulfur contents of target sulfur compounds and their groups in 4 crude oil fractions were also determined. The recoveries for standard sulfur-containing compounds were in the range of 90-102%. The quantitative result of total sulfur in the Oman crude oil fraction sample was compared with those from ASTM D 4294 standard method (total S by X-ray fluorescence spectrometry), the relative deviation (RD%) was 4.2% and the precision of the method satisfactory.

On-line introduction of high-pressure gas-liquid sample for capillary gas chromatographic analysis

An on-line sample introduction technique in capillary gas chromatograph (CGC) for the analysis of high-pressure gas-liquid mixtures has been designed and evaluated. A sample loop of 0.05 muL and a washing solvent loop of 0.5 muL are mounted on a 10-port switching valve, which serves as the injection valve. A capillary resistor was connected to the vent of sample loop in order to maintain the pressure of the sample. Both the sample and the washing solvent are transferred into the split-injection port through a narrow bore fused silica capillary inserted into the injection liner through a septum. The volume of the liner is used both as the pressure-release damper and evaporation chamber of the sample. On-line analysis of both reactants and resultants in ethylene olimer reaction mixture at 5 MPa was carried out, which demonstrated the applicability of the technique. (C) 2004 Elsevier B.V. All rights reserved.

Analysis of chemical constituents of essential oil in purple magnolia leaves by gas chromatography-mass spectrometry

The essential oil in purple magnolia leaves was extracted by steam distillation approaches. The oil obtained was dried with anhydrous magnesium sulfate. According to the analysis of gas chromatography/mass spectrometry, more than 40 peaks were separated and 32 compounds were identified. The identified constituents represent 95% of the peak area of the essential oil. The main compounds were germacrene-D, santolina triene, caryophyllene, 1,3,7-octatriene, 3,7-dimethyl, and camphene, etc.

Correlation analysis of the structures and gas-liquid chromatographic retention indices of amines

Quantitative structure-retention relationship(QSRR) was studied for amines to gas-liquid chromatography on three stationary phases of different polarities with the topological indices A(m) (A(m1), A(m2), A(m3)) and gravitational index GI. The algorithm of "Leaps and Bounds" was performed for selection of the variables. And the multi-regression and the quasi-Newton neural networks were employed for the calculation with better results.

Quantitative structure-property relationship research to the analysis of photoionization sensitivity of organic compounds in gas chromatography

The A(m) index and molecular connectivity index were used for studying the photoionization sensitivity of some organic compounds in gas chromatography. The analysis of structure-property relationship between the photoionization sensitivity of the compounds and the A(m) indices or molecular connectivity indices has been carried out. The genetic algorighm was used to build the correlation model in this field. The results demonstrate that the property of compounds can be described by both A(m) indices and molecular connectivity indices, and the mathematical model obtained by the genetic algorithm was better than that by multivariate regression analysis.

A gas chromatographic analysis of light hydrocarbons on a column packed with modified silica gel

A one-meter long column packed with silica gel is used to separate light hydrocarbons. The silica gel has been modified with several kinds of gas chromatography stationary phases. Among these, PEG 2000 shows fairly good effect when using 80-100 meshes silica gel for the separation of mixture of methane, ethane, ethylene, acetylene, propane, propylene and n-, i-butane. The different behavior of silica gel between batch to batch is also found. When silica gel is coated with a small amount of Al2O3 prepared with sol-gel method, better resolution has been observed on a 2-meter column compared with the non-modified silica gel.