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Abstract  

A series of anion-cation surfactants modified organoclays are prepared by incorporating both cationic surfactant, hexadecyltrimethylammonium bromide (HDTMAB), and anionic surfactant, sodiumdodecyl sulfonate (SDS), to montmorillonite. The added amounts of surfactant varied from 0.2 to 4.0 CEC of the used montmorillonite, similar to those reported in literature. A combination of elemental analysis, X-ray diffraction and thermogravimetric analysis is used in the characterization of the resulting organoclays. The experimental results show that anionic surfactants can not be intercalated into the montmorillonite whereas they can be loaded onto cationic modified montmorillonite, resulting in a further increase of organic carbon content of the resulting organoclays. This study demonstrates that SDS can be intercalated into montmorillonite interlayer space through the interaction with HDTMAB rather than by ion exchange. The intercalation of SDS results in an increase of the basal spacing of the resulting organoclays when comparing with HDTMAB modified montmorillonite and higher decomposition temperature of the intercalated surfactants when comparing with them in bulk state. These new insights are of high importance in the application of organoclays in the fields of remediation of polluted water and synthesis of clay based nanocomposites.

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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.

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Abstract  

The effects of Amoxicillin Sodium and Cefuroxime Sodium on the growth of E. coli DH5α were investigated by microcalorimetry. The metabolic power-time curves of E. coli DH5α growth were determined by using a TAM air isothermal microcalorimeter at 37�C. By evaluation of the obtained parameters, such as growth rate constants (k), inhibitory ratio (I), the maximum heat power (P m) and the time of the maximum heat power (t m), one found that the inhibitory activity of Amoxicillin Sodium vs. E. coli DH5α is enhanced with the increasing of the Amoxicillin Sodium concentration, and the Cefuroxime Sodium has a stimulatory effect on the E. coli DH5α growth when the concentration is about 1 μg mL−1. The IC50 for the Amoxicillin Sodium and the Cefuroxime Sodium are 1.6 and 2.0 μg mL−1, respectively, it implicates that the E. coli DH5α is more sensitive to Amoxicillin Sodium than Cefuroxime Sodium.

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Abstract  

Phase transition behavior of polyesters derived from 2,7-phenanthrene dicarbonic acid diethylester and alkanediols with even methylene carbon number was investigated by the simultaneous DSC-XRD method. The smectic A phase was observed on cooling from the molten state. The transition entropy from the isotropic state to the smectic A phase was about 9.0 J mol-1 K-1, which depended on the methylene carbon number. The linear expansion coefficients, based on the (001) spacing of the crystalline phase at room temperature, were 1.310-4 K-1 (crystalline phase), 5.710-4 K-1 (crystallization region), 1.710-3 K-1 (smectic A phase) during cooling, and 1.510-4 K-1 (crystalline phase), and 1.010-3K-1(melting region) on heating.

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Abstract  

Solvent extraction of protactinium with tri-iso-octyl-amine (TIOA) in xylene, benzene, carbon tetrachloride and chloroform from HCl, HF, HNO3, HClO4 and H2SO4 media was studied using 233Pa as a radiotracer. The extraction efficiencies of protactinium were determined as a function of shaking time, concentrations of mineral acids in aqueous phase, extractant concentrations and diluents in organic phase. The extraction mechanism was discussed. The results show that the extracted species in the organic phase is [(R3NH)nPa(OH)xCl y 5−xy ].

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
Y. Xu
,
W. Yang
,
S. Yuan
,
Y. Xiao
,
X. Zhou
, and
J. He

Abstract  

Osmium isotope, 197Os, produced with 14 MeV neutrons through the reaction of 198Pt(n,2p)197Os, has been identified and its decay properties have been studied with a g(X) spectroscopic method. The ten new g-rays of 41.2, 50.7, 196.8, 199.6, 223.9, 233.1, 250.2, 342.1, 403.6, and 406.4 keV assigned to the decay of 197Os were observed. The half-life of 197Os has been determined as 2.8±0.6 minutes. A partial decay scheme of 197Os was proposed.

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A two-year field experiment with a split-split plot design was conducted to investigate the effects of soil N(0, 120 and 240 kg N·ha−1) and foliar Zn applications at different growth stages (jointing, flowering, early grain filling, and late grain filling) on Zn translocation and utilization efficiency in winter wheat grown on potentially Zn-deficient soil. Our results showed that foliar Zn application at the early grain filling stage significantly increased the Zn concentration in the grain (by 82.9% compared to control) and the Zn utilization efficiency (by 49% compared to jointing). The Zn concentration in the straw consistently increased with the timing of the foliar Zn application and was highest at late grain filling. However, the timing of the Zn application had little effect on Zn uptake in the grain and straw. A high N supply significantly increased the Zn concentration in and uptake by grain and straw, but it had little effect on the efficiency of Zn utilization. Consequently, a foliar Zn application at early grain filling causes Zn to re-translocate into grain from vegetative tissues, resulting in highly nutritional wheat grain. Finally, these practices improved the efficiency of Zn utilization in winter wheat and led to Zn-enriched straw, which may contribute to Zn recycling if it is returned to the field. The results also indicated that N nutrition is a critical factor in both the concentration and translocation of Zn in wheat.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
L. Zhou
,
S. Wen
,
J. Zhao
,
B. Yu
,
B. Han
, and
Ch. Yang

Abstract  

The -ray spectra of188Re decay have been studied by using two Ge/Li/ spectrometers and a three parameters /E-E-T/ List coincidence system. The energies and relative intensities of 52 -rays and cascade relations of 14 -rays are determined. Ten new -rays: 155 /633–478/, 984, 1096, 1463, 1332, 1530, 1574, 1810, 1867, and 1937 keV have been identified. The 155 /633–478/ transition is confirmed and its relative intensity is estimated by means of coincidence experiment. 24 levels of188Re are assigned. Among those, 6 levels are first put into the decay scheme of188Re. In addition to 1443 keV and 1937 keV levels, 1685, 1729 and 1965 keV levels are also observed in the decay of188Ir and other reaction studies. The 1948 level is recently suggested in the190Os/p, t/188Os reaction. The 486 keV and 811 keV -transitions are also put into the level scheme of188Re. The decay branching ratio is deduced.

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Doublesex and mab-3-related transcription factor 1 (Dmrt1) is a Z-linked gene that putatively determines the phenotype of gonads in birds. The sex differential expression of Dmrt1 was examined using wholemount in situ hybridization (WISH) in the urogenital systems during embryogenesis. The results revealed that Dmrt1 showed dimorphic expression in chicken gonads, which increased from day 6.5 to day 10.5. The expression of Dmrt1 in male (ZZ) gonads was not twice as much as in female (ZW) gonads, suggesting the existence of other regulatory mechanisms in addition to Z chromosome dosage effect.

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