Authors:X. Mao, C. Chai, S. Ma, Z. Yang, D. Xu, Y. Sun and Q. Zhang
The concentrations of 14 elements, including Ir, Au, Co, Cr, Fe, Sr, Rb, K, Ta, Zn, Sb, Ba, Sc and Se, in the Wuxi fallen ice were determined by neutron activation analysis. The experimental results show that the relative concentration ratios of Ir/Co, Ir/Cr and Ir/Sc etc. in the ice water (0.0069, 0.00024 and 0.11, respectively) are quite close to those of Type C1 chondrite (0.0102, 0.00021 and 0.092, respectively), which implies that the fallen ice might be a piece of extraterrestrial substance.
Authors:Liu Shengkan, Xu Qigao, Bao Guanxiong, Zhu Yuzhen, Su Weining and Zhang Zhiping
A transmission gauge using neutron- ray beam to measure two parameters simultaneously is reported. In the first place, it was used to measure the moisture m and the mass M of the choir-pottery material sample. The m and M are functions of the neutron transmissivity Tn and the -ray transmissivity T. The parameters of the function relationship can be got by the experiment calibration. Through the practical examination, the measured precision for the mass is 0.4g, for the moisture is 0.1%.
Authors:Li Dong-Mei, Zhang Li-Xing, Wang Xu-Hui and Liu Long-Bo
Atmospheric aerosols are generally collected on filters according to the International Monitoring System (IMS) designed in the Comprehensive Nuclear-Test-Ban Treaty (CTBT). More information could be revealed when the filter sample is pretreated rather than measured directly by g-ray spectrometer. Microwave-assisted extraction (MAE) is a suitable method that gives higher recoveries of elements from glass fibrous filters under different conditions. The results indicate that the MAE is a highly efficient and robust method for the treatment of glass fibrous filter samples. The recoveries of potential fission products from glass fibrous filter samples by microwave-assisted extraction meet the efficiency of the extraction by both aqua regia and 2% HCl.
Authors:J. Yi, F. Zhao, S. Xu, L. Zhang, X. Ren, H. Gao and R. Hu
The decomposition reaction kinetics of the double-base (DB) propellant (No. TG0701) composed of the mixed ester of triethyleneglycol
dinitrate (TEGDN) and nitroglycerin (NG) and nitrocellulose (NC) with cerium(III) citrate (CIT-Ce) as a combustion catalyst
was investigated by high-pressure differential scanning calorimetry (PDSC) under flowing nitrogen gas conditions.
The results show that pressure (2 MPa) can decrease the peak temperature and increase the decomposition heat, and also can
change the mechanism function of the exothermal decomposition reaction of the DB gun propellant under 0.1 MPa; CIT-Ce can
decrease the apparent activation energy of the DB gun propellant by about 35 kJ mol−1 under low pressure, but it can not display the effect under high pressure; CIT-Ce can not change the decomposition reaction
mechanism function under a pressure.
Authors:Jun Zhang, Shuangjun Chen, Jun Su, Xuming Shi, Jing Jin, Xiaolin Wang and Zhongzi Xu
Non-isothermal crystallization kinetics and subsequent melting behavior for three kinds of ethylene-acrylic acid copolymer
(EAA) are investigated via differential scanning calorimetry (DSC). From the Jeziorny method, the crystallization rate of
the primary stage is significantly influenced by the competitive mobility of chains. While the crystallization rate in the
secondary stage decreases in order of acrylic acid (AA) content in copolymers. Mo’s method can also provide a good fitting.
Difference between the Jeziorny method and Mo’s method analysis is because of a higher effect of non-crystallizable chain
ends. The effective activation energy is also determined via Kissinger’s method.
Authors:Guangsong Sun, Hui Xu, Huaming Li, Huoming Shu, Chengtang Liu and Qi Zhang
Gd2O3/Ag3VO4 photocatalysts are synthesized through the impregnation method and characterized by powder X-ray diffraction (XRD), X-ray
photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and UV–vis diffuse reflectance spectra (DRS). It is shown
that Gd3+ is dispersed on the surface of Ag3VO4 in the form of Gd2O3. The DRS analysis indicates that the ability of visible-light absorption of Gd2O3/Ag3VO4 catalysts is enhanced greatly. The photocatalytic activities of the samples are evaluated by degradation of Rhodamine B dye
under UV and visible-light irradiation, respectively. The experimental results show that the role of Gd2O3 content has a significant impact on the photocatalytic activities of the samples. The mechanism of enhanced photocatalytic
activity after the Gd introduction is discussed.
Authors:Yanni Qi, Jian Zhang, Shujun Qiu, Lixian Sun, Fen Xu, Min Zhu, Liuzhang Ouyang and Dalin Sun
Polyaniline/NiO (PANI/NiO) composites were synthesized by in situ polymerization at the presence of HCl (as dopant). FTIR,
TEM and XRD were used to characterize the composites. Thermogravimetry (TG)–mass spectrometer (MS) and temperature modulated
differential scanning calorimetry (TMDSC) were used to study the thermal stability, decomposition and glass transition temperature
(Tg) of the composites, respectively. FTIR and XRD results showed that NiO nanoparticles connected with PANI chains in the PANI/NiO
composites. TEM results exhibited that the morphologies of PANI/NiO composites were mostly spherical, which were different
from the wirelike PANI. TG–MS curves indicated that the products for oxidative degradation of both PANI and PANI/NiO composite
were H2O, CO2, NO and NO2. TG curves showed that with NiO contents increased in PANI/NiO composites, thermal stability of PANI/NiO composites increased
firstly and then decreased when the NiO content was higher than 66.2 wt%. Tg of PANI/NiO composites also increased from 163.19 to 252.36 °C with NiO content increasing from 0 to 50 wt%, and then decreased
with NiO content increasing continuously.
Authors:Zhaojun Sheng, Ruhan Ye, Siyuan Ge, Chenggang Wang, Xuetao Xu, Guangwen Zhang and Ping Luo
An efficient and convenient reversed-phase high-performance liquid chromatography method has been developed and validated for the quantitative determination of cholic acid bulk drugs and their related impurities. Chromatographic separation was performed on a YMC-Pack ODS-AQ column (250 mm × 4.6 mm, S-5 μm, 12 nm), and the mobile phase consisted of acetonitrile, methanol, and diluted formic acid solution (pH 2.5) at a flow rate of 1.0 mL/min. The analytes were monitored using a refractive index detector at 30 °C, and the column temperature was 30 °C. Under the above chromatographic conditions, the method has good specificity and specified impurities can be effectively separated. The proposed method is found to have linearity in the 2.0–80.0 μg/mL concentration range with correlation coefficients of not less than 0.9999. The compounds analyzed in the solutions are stable for at least 7 days, and spike recoveries for all specified impurities range from 91.3% to 109.3% with relative standard deviations (RSDs) not more than 7.3%. The limit of detection and the limit of quantification for the analytes are 0.060 μg/mL and 2.0 μg/mL, respectively. The proposed method can be applied in the quality control assay of cholic acid bulk drugs, with the advantages of simplicity, accuracy, robustness, good selectivity, and high sensitivity.
Traditional Chinese medicine (TCM), which is divided into three subfields, including Chinese medicine, Chinese herb and acupuncture, attracts increasing attentions due to its challenging and significant medical values. This study employs bibliometric analysis to examine the profile of publication activity in TCM field as well as its subfields. The data are retrieved from the Science Citation Index Expanded database during 1980–2009, and 16,536 papers are identified for analysis. Generally speaking, proportions of papers in subfield of acupuncture decreased dramatically, while the proportions of papers of Chinese medicine and Chinese herb rose increasingly. This study finds that East Asia has the largest number of TCM papers, followed by North America and Europe. Furthermore, while China is ranked first in terms of the amount of TCM publications, USA gains the highest percentage of citations. As for regional specialty, mainly, scholars in East Asia publish intensively in Chinese medicine, while most of the scholars in North America and Europe probe into the study of acupuncture. In the latest two decades, China took the first place over Japan in subfields of both Chinese medicine and Chinese herb, while the US has always kept the largest share in acupuncture with a marked upward trend. Regarding the top-ranked TCM institution, Chinese Academy of Sciences located in China, is ranked first in the subfields of Chinese medicine and Chinese herb as well. As for Kyung Hee University, which is located in South Korea, is ranked first in the number of acupuncture papers and Harvard University is ranked first in number of acupuncture citations.
Authors:W. Zhou, X. Y. Zhang, Y. P. Lv, X. D. Liu, C. Xu and G. L. Duan
Radix Isatidis has widely useful activities including anti-virus, anti-bacterial. Tryptanthrin, indigo, and indirubin are active ingredients in R. Isatidis. Response surface methodology (RSM)-optimized infrared-assisted extraction (IRAE) was developed and combined with HPLC for simultaneous determination of tryptanthrin, indigo, and indirubin from R. Isatidis. IRAE were investigated through extraction yields of the three components and optimized by RSM. The optimum conditions were as follows: infrared power of 129 W, solid/liquid ratio of 1:40 g/mL, and irradiation time of 22.5 min. IRAE conditions obtained by RSM were not only accurate, but also had practical value reflecting the expected optimization. Subsequently, this novel IRAE method was evaluated by extraction yield of the components of R. Isatidis samples from different regions. Compared with common extraction methods including maceration extraction (ME), reflux extraction (RE), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE), IRAE showed higher yield with advantages of no limitation of solvent selection, low cost, convenience under optimum extraction conditions. These results suggested the potential of RSM-optimized IRAE for extraction and analysis of the water-/fat-soluble compositions of Chinese herbal medicine. A simple chromatographic separation for simultaneous determination of tryptanthrin, indigo, and indirubin from Chinese herbal medicine R. Isatidis was performed on a C18 column (Diamonsil 150 mm × 4.6 mm i.d., 5 μm) with a mobile phase isocratic consisting of methanol and water at a flow-rate of 0.8 mL min−1. The retention times of tryptanthrin, indigo, and indirubin were 15.4, 31.9, and 58.6 min, respectively. The linear equations were obtained as follows: y = −3094.5744 + 21208.792x for tryptanthrin (R = 0.9998, 0.9–18.0 μg mL−1), y = 4730.0448 + 30180.567x for indigo (R = 0.9997, 0.5–10.0 μg mL−1) and y = −6582.9045 + 67069.312x for indirubin (R = 0.9997, 0.4–8.0 μg mL−1). The result showed that RSM-optimized IRAE was a simple, efficient pretreatment method for the analysis of complex matrix.