Search Results
You are looking at 1 - 10 of 76 items for
- Author or Editor: W. Liu x
- Refine by Access: All Content x
Abstract
The phase behaviour and phase stability of lipids are of importance in an understanding of the biological functions of cell membranes. Among a variety of physical techniques employed to study the phase behaviour and structural properties of polar lipids, differential scanning calorimetry and X-ray diffraction have proved to be successful and are the most frequently used methods. Applications involving a combination of the two techniques, particularly when synchrotron radiation is used as the light source of X-ray diffraction, are reviewed in this article.
Abstract
This paper presents calorimeter measurement for the thermal decomposition of n-propyl nitrate (NPN), isopropyl nitrate (IPN) and 2-ethylhexyl nitrate (EHN). Similar experimental results of triethylene glycol dinitrate (tri-EGDN) and tetraethylene glycol dinitrate (tetra-EGDN) are included for comparison. The potential energy surfaces (PESs) along O-NO2 bond stretch are investigated using the DFT (B3P86, B3PW91 and B3LYP), ab initio Hartree-Fock and PM3 methods. The good coincidence of experimental with theoretical results indicates that initial stage in the thermal decomposition of five nitrates is only unimolecular homolytical dissociation of the O-NO2 bonds and the activation energies of thermolysis by DSC correspond to the energies of O-NO2 bond scission of nitrates.
Abstract
In our invention, FCC (fluid catalytic cracking) dry gas could be used to react with benzene without any special purification, and more than 90% ethylene was converted to ethylbenzene. The phenomenon of carbon deposition over catalyst surface was obvious and leads to a deactivation of catalyst, so it is important to study the behavior of carbon deposition of catalyst during alkylation of benzene. The influence of several factors such as temperature, reaction time, reactant concentration of the amount and the kinetics of carbon deposition were investigated, during which carbon depositing rate equations were obtained for different reactant.
Abstract
Excess molar enthalpies of binary mixtures for tributyl phosphate (TBP)+methanol/ethanol were measured with a TAM air Isothermal calorimeter at 298.15 K and ambient. The results for xTBP+(1–x)CH3OH are negative in the whole range of composition, while the values for xTBP+(1–x)C2H5OH change from positive values at low x to small negative values at high x. The experimental results have been correlated with the Redlich–Kister polynomial. IR spectra of the mixtures were measured to investigate the effect of hydrogen bonding in the mixture.
Abstract
This study investigated the community structure of ciliates in Gahai Alpine Wetland of Qinghai-Tibetan Plateau, China. We hypothesized that the ciliate community in the Plateau is more complex and the species diversity is richer than those in other climate zones of China. In particular, we studied how the ciliate species responded to environmental temperature, soil moisture content and the manner of pasture utilization. We determined key features of the ciliate communities such as trophic functional groups, ciliate seasonal distribution, species diversity and similarity index at six sample sites from January 2015 to October 2016. To count and characterize ciliates, we combined the non-flooded Petri dish method with in vivo observation and silver staining. We identified 162 ciliate species in this area, showing a high species and functional diversity. The mode of nutrition was diverse, with the lowest number of ciliates in group N (Nonselective omnivores, 4 species) and the highest number in group B (Bacterivores-detritivores, 118 species, corresponding to 73% of the total species number). Ciliate species richness was significantly positively correlated with environmental temperature and moisture and adversely related to the intensity of agricultural land use. Rotational grazing by livestock or suspended grazing might be useful for maintaining good soil quality, thereby favoring ciliate diversity. Our study may serve as a reference to evaluate the ecosystem status of the Gahai Alpine Wetland and other similar areas in future studies.
Wheat kernel morphology is a very important trait for wheat yield improvement. This is the first report of association analysis of kernel morphology traits in wheat breeding lines. In Qinghai, China, the research described here involved genome-wide association analysis in breeding lines derived from synthetic hexaploid wheat with a mixed linear model to identify the quantitative trait loci (QTLs) related to kernel morphology. The 8033 effective Diversity Array Technology (DArT) markers produced a genetic map of 5901.84 cM with an average density of 1.36 markers/cM. Population structure analysis classified 507 breeding lines into three groups by Bayesian structure analysis using unlinked markers. Linkage disequilibrium decay was observed with a map coverage of 2.78 cM. Marker-trait association analysis showed that 15 DArT markers for kernel morphology were detected, located on nine chromosomes, and explained 2.6%–4.0% of the phenotypic variation of kernel area (KA), kernel width (KW), kernel length (KL) and thousand-kernel weight (TKW). The marker 1139297 was related to both the KL and KA traits. Only six DArT markers were close to known QTLs. The parent SHW-L1 carried eight favored alleles, while other seven favored alleles were derived from elite common wheat cultivars. These QTLs, identified in elite breeding lines, should help us understand the kernel morphology trait better, and to provide germplasm for breeding new wheat cultivars for Qinghai Province or other regions.
Glutenin subunit alleles at the Glu-D3 locus and their effects on dough properties, pan bread, and dry white Chinese noodle (DWCN) qualities were investigated using 106 winter and facultative wheat cultivars and advanced lines. Allele Glu-D3c (42.5%) was the most frequent glutenin subunit, followed by Glu-D3b (25.5%) and Glu-D3a (23.6%). Glu-D3d and Glu-D3f occurred in only three and six cultivars, respectively. The effect of Glu-D3 was significant forDWCNquality, accounting for up to 16% of the variation, but there were no significant differences between individual Glu-D3 alleles on dough properties and qualities of DWCNand pan bread. Interaction effects Glu-A1 × Glu-D3 and Glu-B1 × Glu-D3 were significant for DWCN quality and loaf volume. More work is needed to understand the effects of Glu-D3 variation on the determination of dough properties and end-use quality.
Abstract
An attempt has been made to develop a radiochemical methodology for the decontamination of a trace amount of radioactive cesium from a bulk amount of natural NaCl by liquid-liquid extraction (LLX). Open chain crown ethers, of amide type, namely, N,N,N",N"-tetraphenyl-3,6-dioxaoctanediamide (TDD), N,N,N",N"-tetraphenyl-3,6,9-trioxaundecanediamide and N,N"-dinaphthyl-N,N"-diphenyl-3,6-dioxaoctanediamide (DDD) have been chosen for this purpose. The separation factor between Cs and Na is the highest when 10-4M TDD dissolved in nitrobenzene is used as extractant and 0.4M picric acid at pH 5.0 is used as aqueous phase. About 60% Cs is extracted in this condition in a single run.
Abstract
Two different radiochemical procedures were developed: chelate ion resin exchange and amine solvent extraction. Two kinds of new Chinese chelate resins (NANKAI-3926 and BEI-5) and a new longchain primary amine N1923 were compared with the Srafion NMRR and the tertiary amine N235 in absorption performance of noble metals, respectively. Influences of various experimental conditions, e. g. sample digestion, acidity, equilibrium time, as well as elution of noble metals, on analytical sensitivity and chemical yield were discussed. Combining with neutron activation, the radiochemical separation procedures developed were used to determine the noble metal contents in the geological samples from Permian/Triassic boundary in South China.
Abstract
Mn2O3/
-Al2O3 catalysts were prepared by the impregnation method, and the maximum monolayer dispersion capacity or dispersion threshold value of Mn2O3 on the surface of -Al2O3 was determined to be 13.08% from the decomposition mass loss of supported Mn(NO3)2 in the monolayer state. This was compared with the values estimated from a close-packed monolayer model and an interaction model. It was confirmed that the high activities and selectivities of the catalysts for benzoic acid hydrogenation to benzaldehyde are due to the monolayer dispersion of the Mn2O3 on the surface of -Al2O3.
