Authors:Li Xi, Liu Yi, Wu Jun, Liang Huigang, and Qu Songsheng
The action of three kinds of the selenomorpholine compounds on a strain ofEscherichia coli was studied by microcalorimetry. Differences in their capacities to affect the metabolism of this bacterium were observed.
The extent and duration of the effect on the metabolism as judged from the rate constant (k) of Escherichia coli (in log phase) varied with the different drugs. The kinetics show that selenomorpholine compounds had an effect on the metabolism
process of Escherichia coli. The k of Escherichia coli in the presence of the drugs increased with the increasing concentrations of the drugs (C) at low concentration; but at high concentration, the rate constant decreased with the increasing concentrations of the drugs.
The experimental results reveal that the sequence of antibiotic activity of selenomorpholines is: N-selenomorpholinemethyl
succinimide and its hydrochloride>N-(α-selenomorpholinebenzyl) succinimide.
Authors:Jianfei Ding, Rong Shao, Jun Wu, Zhangfeng Qin, and Jianguo Wang
The dehydrogenation of isobutane to produce isobutene coupled with reverse water gas shift (RWGS) reaction in the presence of carbon dioxide was investigated over a NiO/γ-Al2O3 catalyst. The results illustrated that the coupling dehydrogenation of isobutane in carbon dioxide over NiO/γ-Al2O3 catalyst is effective, and the NiO/Al2O3 catalyst was modified with deposited carbon by impregnation of alumina with an aqueous solution of Ni(H2NCH2CH2NH2)x (NO3)2. Carbon modification can decrease the total acidity of the NiO/γ-Al2O3 catalyst and enhance the dispersion of NiO active phase. Furthermore, carbon has low acidity and anti-coking performance, so the carbon modification is effective in suppressing the coke formation and side reactions occurrence. Therefore, the catalyst stability and the isobutene selectivity are improved significantly by the carbon modification.
Authors:Jianfei Ding, Ligen Chen, Rong Shao, Jun Wu, and Wantian Dong
The catalytic hydrogenation of p-nitrophenol to produce p-aminophenol (PAP) was carried out over the catalyst nickel supported on active carbon (AC). The calcination temperature was one of the most important technical conditions: temperature higher than 450 °C would result in the reduction of NiO to Ni phase by AC and the loss of support. The surface area and nickel dispersion over catalyst decreased obviously after 450 °C calcination temperature because of the loss of support and the Ni phase sintering. Addition of K2O enhanced the alkalinity of the Ni/AC catalyst, and the p-nitrophenol stuff performed rather stronger acidity. Therefore, the level of p-nitrophenol adsorption over Ni/AC catalyst was improved, and the reaction efficiency was enhanced consequently. The p-nitrophenol conversion and PAP selectivity reached 97.7 and 99.3% over Ni–K2O/AC catalyst, respectively. During the process of catalytic hydrogenation, higher PAP selectivity was kept successively. It indicated that no side reactions happened during the catalytic hydrogenation of p-nitrophenol.
Authors:Yang Ya-xin, Liu Qing-cheng, Wu Xin-min, Huang Yan-jun, Lin Jun, Wu Ya-mei, Li Shu-zhen, and Hsia Yuan-fu
A new air radon monitor is proposed based on the combination of an aluminum disk and an electric multilevel clearance system
(EMCS). The positively charged, small aluminum disk has a high collection ability to radon with a collection efficiency of
about 60%. The old radon progenies were eliminated by the EMCS in the air entrance of the monitor with an efficiency of about
99%. The monitor was calibrated in the national standard radon chamber in Hengyang, China. Compared to the radon double-filter
equipment, the results, gained by both apparatus, coincide with each other.
Thermotropic phase behaviors of paeonol-encapsulated liposomes containing stigmasterol or cholesterol have been investigated by differential scanning calorimetry. We compared the thermotropic phase behavior of pure dipalmitoylphosphatidylcholine (DPPC) liposomes, sterol/DPPC liposomes, and paeonol/sterol/DPPC liposomes increasing the ratio of paeonol to sterol from 0 to 1, by analyzing the calorimetric parameters of main phase transition of liposomes including phase transition temperature (onset temperature and peak temperature) and phase transition cooperativity. The results showed that paeonol could incorporate into the hydrophobic region of DPPC, thus, decrease phase transition temperature of DPPC. Though stigmasterol interacts with DPPC less favorably than cholesterol, thermotropic phase behavior of paeonol/cholesterol/DPPC liposomes and that of paeonol/stigmasterol/DPPC liposomes are very similar. A phase separation occurred when the molar ratio of paeonol to sterol reached 1:1 in paeonol-encapsulated liposomes, where a paeonol-rich domain coexisted with a sterol-rich domain. The packing order of acyl chains of DPPC in sterol-rich domain is a little higher than that in paeonol-rich domain.
Authors:Wang Mingming, Xie Hongqin, Tan Liqiang, Qiu Jun, Tao Xingquan, and Wu Cuiping
Herein, the sorption properties of Eu(III) on Na-attapulgite were performed by using batch sorption experiments under different
experimental conditions, such as contact time, pH, ionic strength, humic acid and temperatures. The results indicated that
the sorption of Eu(III) on Na-attapulgite was strongly dependent on pH and temperature. At low pH values, the sorption of
Eu(III) was influenced by ionic strength, whereas the sorption was not affected by ionic strength at high pH values. The sorption
of Eu(III) was mainly dominated by ion exchange or outer-sphere surface complexation at low pH values, and by inner-sphere
surface complexation or surface precipitation at high pH values. The sorption of Eu(III) onto Na-attapulgite increased with
increasing temperature. The Langmuir and Freundlich models were applied to simulate the sorption isotherms, and the results
indicated that the Langmuir model simulated the sorption isotherms better than the Freundlich model. The thermodynamic parameters
(∆Go, ∆So, ∆Ho) were calculated from the temperature dependent sorption isotherms at 293, 313 and 333 K, respectively, and the results indicated
that the uptake of Eu(III) on Na-attapulgite was an endothermic and spontaneous process. The results of high Eu(III) sorption
capacity on Na-attapulgite suggest that the attapulgite is a suitable material for the preconcentration and immobilization
of Eu(III) ions from large volumes of aqueous solutions.
Authors:Kai Zheng Fang, Dao Bin Mu, Shi Chen, Feng Wu, and Xiao Jun Zeng
The thermal behavior of D-type Ni–MH battery during charging was investigated at a wide range of ambient temperatures in this work. The temperature measurement of the battery was conducted by using a thermal infrared imager put in a high–low temperature chamber. The ambient temperatures were controlled to −10, 0, 10, 20, 30, and 40 °C during charging. The battery was charged to SOC of 110% in the rate of 1C, 3C, and 5C. Real-time infrared thermal images of battery surface were obtained during charging, as well as temperature change curves. The maximum surface temperature of the battery at the end of charging was stimulated at a higher ambient temperature by curve fitting. It is indicated that the temperature gradient on battery surface will increase with charging rate increase, and the rate of actual temperature rise is almost unrelated to ambient temperature. The simulating result shows that the maximum surface temperature would be over 101 °C if the battery is charged in the rate of 5C under an ambient temperature of 70 °C, which may lead to a safe accident.
Authors:Jinxue Wang, Min Liu, Xinwen Guo, Hongyu Wu, Jun Xu, and Wenqi Lu
Supported Ag/TS-1 catalysts were prepared by the cool plasma sputtering technique and characterized by BET, SEM/EDX, XRD, UV–Vis and TEM techniques. The Ag loading and particle size on TS-1 were tailored by sputtering time. The catalytic performance of the supported catalysts was tested in the gas-phase propene epoxidation reaction using H2 and O2 at a space velocity of 4000 h−1, and atmospheric pressure. Ag/TS-1 with 1.0–19.9 wt% Ag loading and a Ag particle size around 10–40 nm exhibited a selectivity above 90% in the propene epoxidation reaction at a suitable temperature. Catalysts with high Ag loading and large Ag size cause H2 combustion in O2, leading to propene combustion. The heat evolved in the reaction process may lead to over-oxidation of propene to CO2.