Authors:Ling Zhang, Huan Zhao, Qiushi Li, Juan Wang, and Xin Tan
An article assessment system based on both Tianjin University and nine key Chinese Universities’ academic disciplinary benchmarks
was established to evaluate researcher’s published papers. With this scientific benchmarking system, the quality of a researcher’s
papers could be easily located in a percentile scale in corresponding field within certain groups. Several factors, including
total number of papers, order of authors, impact of journals, citation count, h-index, e-index, a-index, m-quotient, etc.,
were also utilized for both quantity and quality analysis. Furthermore, the novel proposed weighted citation analysis was
introduced to judge a researcher’s contribution to his/her research outcomes. The convenient application and comprehensive
evaluation property of this assessment system was thoroughly discussed via a given example.
Authors:Jifen Wang, Huaqing Xie, Yang Li, and Zhong Xin
Phase change nanocomposites were prepared by dispersing γ-Al2O3 nanoparticles into melting paraffin wax (PW). Intensive sonication was used to make well dispersed and homogeneous composites.
Differential scanning calorimetric (DSC) and transient short-hot-wire (SHW) method were employed to measure the thermal properties
of the composites. The composites decreased the latent heat thermal energy storage capacity, Ls, and melting point, Tm, compared with those of the PW. Interestingly, the composites with low mass fraction of the nanoparticles, have higher latent
heat capacity than the calculated latent heat capacity value. The thermal conductivity of the nanocomposites was enhanced
and increased with the mass fraction of Al2O3 in both liquid state and solid state.
The influence of the activation conditions on the catalytic performance and microstructure of supported V–Mo oxides used for benzene oxidation to maleic anhydride has been investigated. To activate the catalysts, two sets of activation conditions were tested. In condition I, the catalysts were activated in an atmosphere of air and benzene, which was similar to the industrial practice. In condition II, the catalysts were pre-activated in an atmosphere consisting of the gas products produced by the decomposition of the freshly prepared catalysts during activation process. The activity and selectivity of the catalysts were evaluated on a bench scale reactor as well as on a pilot reactor. The catalysts activated by condition II at the appropriate temperature showed a better performance: the selectivity and yield of MA were nearly 80 and 100 wt%, respectively. They are 5 % higher than those of the catalyst activated by condition I. The catalysts were characterized in terms of several techniques including isotherm adsorption, TG-DTG, XRD, SEM, EDX and XPS. The characterization results indicated that the microstructures of the catalysts were significantly influenced by the activation conditions. Based on the above information, the better performance exhibited by the catalyst activated by condition II are analyzed.
Authors:Zongxue Yu, Yuxi Sun, Wenxian Wei, Lude Lu, and Xin Wang
Orthorhombic structural perovskite NdCrO3 nanocrystals with size of 60 nm were prepared by microemulsion method, and characterized by XRD, TEM, HRTEM, SEM, EDS and
BET. The catalytic effect of the NdCrO3 for thermal decomposition of ammonium perchlorate (AP) was investigated by DSC and TG-MS. The results revealed that the NdCrO3 nanoparticles had effective catalysis on the thermal decomposition of AP. Adding 2% of NdCrO3 nanoparticles to AP decreased the temperature of thermal decomposition by 87° and increased the heat of decomposition from
590 to 1073 J g−1. Gaseous products of thermal decomposition of AP were NH3, H2O, O2, HCl, N2O, NO, NO2 and Cl2. The mechanism of catalytic action was based on the presence of superoxide ion O2− on the surface of NdCrO3, and the difference of thermal decomposition of AP with 2% of NdCrO3 and pure AP was mainly caused by the different extent of oxidation of ammonium.
Two crystal samples, sodium 5-methylisophthalic acid monohydrate (C9H6O4Na2·H2O, s) and sodium isophthalic acid hemihydrate (C8H4O4Na2·1/2H2O, s), were prepared from water solution. Low-temperature heat capacities of the solid samples for sodium 5-methylisophthalic acid monohydrate (C9H6O4Na2·H2O, s) and sodium isophthalic acid hemihydrate (C8H4O4Na2·1/2H2O, s) were measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 379 K. The experimental values of the molar heat capacities in the measured temperature region were fitted to a polynomial equation on molar heat capacities (Cp,m) with the reduced temperatures (X), [X = f(T)], by a least-squares method. Thermodynamic functions of the compounds (C9H6O4Na2·H2O, s) and (C8H4O4Na2·1/2H2O, s) were calculated based on the fitted polynomial equation. The constant-volume energies of combustion of the compounds at T = 298.15 K were measured by a precise rotating-bomb combustion calorimeter to be ΔcU(C9H6O4Na2·H2O, s) = −15428.49 ± 4.86 J g−1 and ΔcU(C8H4O4Na2·1/2H2O, s) = −13484.25 ± 5.56 J g−1. The standard molar enthalpies of formation of the compounds were calculated to be ΔfHmθ (C9H6O4Na2·H2O, s) = −1458.740 ± 1.668 kJ mol−1 and ΔfHmθ(C8H4O4Na2·1/2H2O, s) = −2078.392 ± 1.605 kJ mol−1 in accordance with Hess’ law. The standard molar enthalpies of solution of the compounds, ΔsolHmθ(C9H6O4Na2·H2O, s) and ΔsolHmθ(C8H4O4Na2·1/2H2O, s), have been determined as being −11.917 ± 0.055 and −29.078 ± 0.069 kJ mol−1 by an RD496-2000 type microcalorimeter. In addition, the standard molar enthalpies of hydrated anion of the compounds were determined as being ΔfHmθ(C9H6O42−, aq) = −704.227 ± 1.674 kJ mol−1 and ΔfHmθ(C8H4O4Na22−, aq) = −1483.955 ± 1.612 kJ mol−1, from the standard molar enthalpies of solution and other auxiliary thermodynamic data through a thermochemical cycle.
New types of S2O82−/Al-x wt%Ce–Zn–O solid acid catalysts were prepared by the sol–gel method. Their catalytic performances for the synthesis of n-butyl acetate from acetic acid and n-butanol were investigated. The characterization of prepared catalysts was performed using XRD, IR, TG-DSC and SEM. The experimental results showed that the S2O82−/Al-2.5 wt%Ce–Zn–O solid acid catalyst exhibited an optimal esterification performance with 98.71% esterification efficiency under the optimum synthesis conditions. Moreover, the S2O82−/Al-2.5 wt%Ce–Zn–O solid acid catalyst retained its high activity with above 95% esterification efficiency after being used repeatedly for seven times, which indicated that the S2O82−/Al-2.5 wt%Ce–Zn–O solid acid catalyst had excellent stability.
Authors:Libin Wang, Xi Li, Le Mi, Xin Shen, Tian Feng, Xueying Liu, and Qingwei Wang
2′,4′,6′,4-Tetra-O-acetylphloretin (TAPHL) is a prodrug of phloretin (PHL) in which the OH groups are protected by acetylation. A validated liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the determination of PHL in rat biological matrices was developed and applied to investigate and compare the pharmacokinetics, tissue distribution, and excretion of PHL and TAPHL in rats following a single oral administration. The method was validated for accuracy, precision, linearity, range, selectivity, lower limit of quantification (LLOQ), recovery, and matrix effect. All validation parameters met the acceptance criteria according to regulatory guidelines. The mean pharmacokinetic parameters of tmax, Cmax, AUC(0 − t), CL/F, and t1/2 were observed after oral administration in rats. The data showed that PHL was absorbed and eliminated rapidly from plasma after oral administration. The pharmacokinetic properties are improved, such as the tmax has been prolonged and the area under the curve (AUC) has been enhanced after oral administration of TAPHL to rats. Tissue distribution results indicated that PHL could be rapidly and widely distributed into tissues but could not effectively cross the blood–brain barrier in rats. After oral administration of TAPHL to rats, its tissue distribution to rats was similar as that after oral administration of equimolar PHL. In addition, higher recoveries of PHL following administration of TAPHL indicated that TAPHL might reduce the excretion of PHL from the body by reducing the first pass effect.
Authors:Fang Geng, Nan Hu, Ji-Fang Zheng, Cheng-Lei Wang, Xin Chen, Jia Yu, and De-Xin Ding
The objective of this study was to evaluate the potential ecological danger and toxic effect of uranium mill tailings leaching
solution (UMTLS) on aquatic animals. UMTLS was identified to contain two radioactive elements, nine heavy metal elements,
and five non-metallic materials. The acute toxicity test indicated that the 1, 12, 24, 48, 72, 96 h LC50 values of UMTLS to the zebrafish were 12.1, 7.1, 4.4, 3.8, 3.4, and 2.9%, respectively. In sub-lethal toxicity tests, superoxide
dismutase, catalase, Na+–K+–ATPase activities, and malondialdehyde content were respectively determined and analyzed in the zebrafish gill, gonad, muscle,
and liver after exposed to four different concentration levels of UMTLS for 7 and 14 days, respectively. The result showed
that the most sensitivity of the antioxidant system in zebrafish tissues in UMTLS was gill, and then decreased in gonad, muscle
and liver respectively. Na+–K+–ATPase activity in the liver and gonad may be considered as a reference biomarker of UMTLS stress. The data in this study
may be valuable that the toxicity of such as the leaching solution of potentially hazardous material was compared with that
of each constituent.