Authors:Songsheng Jiang, Zhiyuan Chang, Min Zhao, Yonggang Zhao, X. L. Zhao, and W. E. Kieser
Under an IAEA project for upgrading of reference materials, a new determination of the 129I concentration in the IAEA-375 reference material was performed. A chemical procedure was set up for the preparation of the AgI samples. Measurement of 129I was carried out using the IsoTrace Tandetron AMS facility at University of Toronto. To ensure the accuracy of the calibration, the tuning of the AMS system was iterated using not only the QC (quality control) samples but also all unknown samples. To minimize any possible current-dependent effects between 129I and 127I ions in the injection magnet, low Cs+ sputtering beam intensity (10 μA) was used. The reproducibility in determining the 129I/127I ratio in the IAEA-375 AgI samples was less than 1%. The activity concentration (CA) of 129I in the IAEA-375 reference material was determined to be 1.59±0.08 mBq . kg-1 at 95% confidence level. The present value is about 7% lower than the IAEA recommended value (1.7 mBq . kg-1) listed in 2000 or 20% lower than the recommended value (2 mBq . kg-1) listed in the IAEA AQCS Reference Material Catalogue (2002-2003). Since the IAEA recommended values for IAEA-375 materials was issued about 10 years ago and error range of the recommended values were large, the results we obtained might be useful in upgrading the recommended value.
Authors:Hong-Xiang Zhao, Bao-Huai Wang, and You-Min Zhang
The thermal curves and the enthalpy changes of the interaction between some oral sustained release preparations (Contac, Fenbid
and Benza sustained release capsules) and physiological saline have been measured at 298.15 K with a MS-80 standard Calvet
microcalorimeter. The curves that recorded the changes of heat effect with time have clearly shown the sustained release action
and process of the above preparations. A method for examining the sustained release action of sustained release preparations
can be developed from the above experiments. The principle of application and the experimental procedure of this method have
been expounded, and some results of the above experiments have also been discussed.
Authors:Dai Zhongning, Ren Chigang, Yang Fujia, Zhao Quanhong, Min Qiubao, and Wang Pingxian
The m-PIXE setup of Fudan University has been used to study the trace elements of ostracode shells. Program TSPIXE was used to calculate their trace element concentrations.Stenocypris derupta Vavra, Dolerocypria mukaishimensis okubo andTanella opima Chen, three kinds of ostracodes were analyzed. In this study, we concentrate on the relationships between molar ratios of Mg/Ca and temperature, and between molar ratios of Mg/Ca and salinity of the host water. We have found that the molar ratios of Mg/Ca of ostracize shells are positively correlated with the temperature of the host water, but negatively correlated with its salinity.
Authors:Yanan Wang, Huanhui Chen, Guoqing Zhao, Min Liu, Xuewei Lang, and Zhirong Zhu
The aldol condensation of methyl acetate with formaldehyde to form methyl acrylate was studied in a continuous-flow reactor using a series of supported cesium basic catalysts with commercially available materials (ZSM-5, SiO2, and γ-Al2O3) as carriers prepared by vacuum impregnation. The catalysts were characterized by N2 adsorption-desorption, Fourier transform-infrared (FT-IR), X-ray diffraction (XRD), and temperature-programmed desorption of ammonia and carbon dioxide (NH3/CO2-TPD). The obtained results indicated that the selectivity of methyl acrylate was mainly influenced by the properties of supports. The formation of acetone is approximately proportional to the acidity of supports. The basicity of the catalysts was favorable to the formation of methyl acrylate according to the results of CO2-TPD. The hydrolysis of methyl acetate was inhibited over Cs-HT-SiO2 prepared by SiO2 after hydrothermal treatment. Furthermore, SiO2 with the large mesoporous volume is superior to other supports, which shows the best catalytic activity for the aldol condensation reaction. On the other hand, the catalytic performance of zeolite basic catalysts was strongly influenced by the effect of reactant diffusion. Internal diffusion resulted in the increase of conversion of methyl acetate with increasing specific surface area, while the conversion of methyl acetate decreased with increasing the weight hourly space velocity (WHSV) due to the external diffusion.
Authors:Kang-Zhen Xu, Yong-Shun Chen, Min Wang, Jin-An Luo, Ji-Rong Song, Feng-Qi Zhao, and Rong-Zu Hu
A novel energetic material, 4,5-dihydroxyl-2-(dinitromethylene)-imidazolidine (DDNI), was synthesized by the reaction of FOX-7 and glyoxal in water at 70 °C. Thermal behavior of DDNI was studied with DSC and TG-DTG methods, and presents only an intense exothermic decomposition process. The apparent activation energy and pre-exponential factor of the decomposition reaction were 286.0 kJ mol−1 and 1031.16 s−1, respectively. The critical temperature of thermal explosion of DDNI is 183.78 °C. Specific heat capacity of DDNI was studied with micro-DSC method and theoretical calculation method, and the molar heat capacity is 217.76 J mol−1 K−1 at 298.15 K. The adiabatic time-to-explosion was also calculated to be a certain value between 14.54 and 16.34 s. DDNI presents lower thermal stability, for its two ortho-hydroxyl groups, and its thermal decomposition process becomes quite intense.
Authors:Ye Yu-xing, Hu Jin-xin, Huang Zi-lin, Shi Wei-qun, Wu Guang-min, Tang Hong-bin, Zhu Wen-bin, Wang Xiao-rong, Zhao Hu-gen, Dong Yu, Sheng Dong, Luo Fang-xiang, and Zhao Yan-ju
The partitioning of actinides from simulated high level liquid waste (HLLW) originated from the Purex process has been studied using a mixture of dihexyl N,N-diethylcarbamoylmethyl-phosphonate (DHDECMP) and tributylphosphonate (TBP) in kerosene (OK). The distribution ratios of actinides were investigated as a function of a number of parameters such as the concentration of nitric acid, salting-out reagent, Gd(III) in the aqueous phase, extractant in the organic phase, and temperature. The extraction complexes, extraction reaction constant k, and thermodynamic parameters H, G and S were determined. The extraction of actinides from simulated HLLW by DHDECMP-TBP/OK has been carried out using a miniature countercurrent centrifugal contactor. The results show that the removal efficiency of actinides is greater than 99.9%. A conceptual flowsheet for the removal of actinides from HLLW is proposed.
Authors:Chuan-Min Qi, Yong He, Xiao Wang, Man Feng, Jing-Li Xu, Rui Ding, Hang Liu, Yu-Rong Chen, Fang Li, Zhao-Hui Zhu, Yong-Hong Dang, Shu-Ting Zhang, and Ying Xie
d-glucosamine at concentration of certain range could kill tumor cells without influencing normal cells. There are also some
reports on the antitumor activity of d-glucosamine and its derivatives in murine models. It was therefore postulated that d-glucosamine might have the potential to invade tumor cells. We designed and radiosynthesized a glucosamine derivative, N-(2-[18F]fluoro-4-nitrobenzoyl)glucosamine ([18F]FNBG([18F]7)). Evaluations in vitro and in vivo were performed on tumor bearing mice. Excitingly, the radiochemical purity of [18F]FNBG([18F]7) was 99%, and besides the best radiochemical yield was up to 35%. The best T/Bl (Tumor/Blood) and T/M (Tumor/Muscle) ratios
of [18F]FNBG([18F]7) were 4.40 and 4.84. Although [18F]FNBG([18F]7) deserved further studies, the results revealed it might become a potential PET imaging agent for detecting tumors.
Authors:Yong He, Rui Ding, Hang Liu, Xiao Wang, Jing-Li Xu, Man Feng, Yu-Rong Chen, Chuan-Min Qi, Cheng Peng, Zhao-Hui Zhu, Yong-Hong Dang, Ming Wang, and Yun-Chuan Ma
As degradation product of Antineoplaston A10 in vivo, phenylacetyl glutamine showed antitumor activities. According to literatures,
we designed and radiosynthesized a phenylacetyl glutamine derivative, which was achieved under a mild reaction condition.
Evaluations in vitro and in vivo were performed on tumor bearing mice. Excitingly, the radiochemical purity of (S)-2-((S)-2-(4-(3-fluoropropyl)benzamido)-3-phenylpropanamido)pentanedioic
acid ([18F]FBPPA) was 98%, and besides the best radiochemical yield was up to 46%. T/Bl (Tumor/Blood) and T/M (Tumor/Muscle) ratios
of [18F]FBPPA at 60 min post injection were 2.33 and 3.51. Meanwhile, it showed satisfied stability in vitro and in vivo, compared
with 2-[18F]fluorodeoxyglucose ([18F]FDG). Although [18F]FBPPA deserved further studies to make optimizations on its structure, the results revealed it might become a potential
PET imaging agent for detecting tumors.