TG and DTA analysis of Y1−xCaxBa2Cu3O7−y suggests that the stability of the 123 phase increases with increasing Ca contents. The O(1) in the Cu(1)-O chain is unstable
but O(2) and O(3) in Cu(2)-O planes are very stable. There are hardly any oxygen vacancies in the Cu(2)-O plane. The replacement
of Y by Ca does not make oxygen vacancies in Cu(2)-O planes but leads to an increase in the oxidation number of copper in
Authors:Z. Ren, Y. Mao, Q. Zhi, C. Xu, and T. Dong
The synthesis of superheavy elements is now a hot topic in nuclear physics. Alpha-decay and spontaneous fission are two main
decay modes in heavy and superheavy regions. Theoretical studies on alpha radioactivity and spontaneous fission can provide
useful information for experiments. We investigate the alpha-decay and spontaneous fission of heavy and superheavy nuclei
with different models. This includes the alpha-decay energies, alpha decay half-lives, and half-lives of spontaneous fission.
The theoretical alpha-decay half-lives are in good agreement with experimental ones. The calculated half-lives of spontaneous
fission are in reasonable agreement with present data. The properties of unknown nuclei are predicted.
Authors:Z. Ren, W. Liu, Y. Hou, Y. Zhu, L. Chang, and D. Ma
Thermogravimetry (TG) was employed to study the thermal degradation kinetics of poly(etherketone/sulfone)ethylimide (PEK-IE and PES-IE). The corresponding decomposition activation energies and reaction orders were obtained and the comparison was made with their parent polymerspoly(ether-ketone/sulfone) with Cardo group (PEK-C and PES-C). The results show that the degradation activation energies of PEK-IE and PES-IE were lower than that of PEK-C and PES-C; and two stages of the degradation process were found for all the four polymers. For PEK-IE and PES-IE, the activation energies in the first decomposition stage are much lower than that in the second stage and the two stages can be taken as slow induction and fast degradation, whereas for PEK-C and PES-C the activation energies in the first decomposition stage are larger than that in the second stage, and the two stages can both be taken as two fast degradation stages. The decomposition mechanism of the two stages was also speculated.
Authors:X. Han, Y. Hu, Z. Lin, S. Li, F. Zhao, Z. Liu, J. Yi, L. Zhang, and X. Ren
Effects of fullerenes including FS, EFS and pure C60 on thermal behaviors of polyethylene glycol (PEG) have been studied by employing thermogravimetry-differential thermogravimetry
(TG-DTG), differential scanning calorimeter (DSC) and off-line furnace-type pyrolysis-gas chromatography/mass spectrometry
(Py-GC/MS). The products were collected by Cambridge filter pad which was widely used in analyzing the combustion products
of cigarette. The results showed that the addition of fullerenes obviously restrained the thermal decomposition of PEG. The
initial decomposition temperatures (IDT) and maximum decomposition peak temperatures (MDT) were evidently postponed by the
addition of fullerenes. Pyrolysis products with one or two hydroxyl end groups obviously increased with the addition of 10%
C60. The reasons of the changes were discussed from the aspects of reaction mechanisms.
Authors:H. L. Huo, S. H. Yu, X. Z. Liu, Y. Meng, Y. P. Ren, and L. T. Zhang
A selective and sensitive liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) method was developed and validated for analysis of xanthotoxol (1), xanthotoxin (2), isoimpinellin (3), bergapten (4), oxypeucedanin (5), imperatorin (6), cnidilin (7), and isoimperatorin (8) in rat bile and urine using pimpinellin as an internal standard (IS). An Agilent 1200 liquid chromatography system (Agilent Technologies, USA) equipped with a quaternary pump, an autosampler, and a column compartment was used for all analyses. Chromatographic separations were performed on a Sapphire C18 column (150 mm × 4.6 mm, 5 μm), and the column temperature was maintained at 30°C; the sample injection volume was 10 μL. The specificity, linearity, accuracy, precision, recovery, matrix effect, and several stabilities were validated for all analytes in the rat bile and urine samples. The method was successfully applied in monitoring the concentrations of eight coumarins in rat bile and urine after a single oral administration of Radix Angelicae Dahuricae extract with a dosage of 8.0 mL/kg. In the bile samples, the eight coumarins excreted completely in twenty-four hours. The average percentages of coumarins (1–8) excreted were 0.045%, 0.019%, 0.177%, 0.105%, 0.337%, 0.023%, 0.024%, 0.021%. In the urine samples, the eight coumarins excreted completely in seventy-two hours. The average percentages of coumarins (1–8) excreted were 1.78%, 0.095%, 0.130%, 0.292%, 0.082%, 0.008%, 0.005%, 0.004%. The method is robust and specific and it can successfully complete the requirements of the excretion study of the eight coumarins in Radix Angelicae Dahuricae.
Authors:H. X. Ma, B. Yan, Y. H. Ren, Y. Hu, Y. L. Guan, F. Q. Zhao, J. R. Song, and R. Z. Hu
3,3-Dinitroazetidinium (DNAZ) salt of perchloric acid (DNAZ·HClO4) was prepared, it was characterized by the elemental analysis, IR, NMR, and a X-ray diffractometer. The thermal behavior and decomposition reaction kinetics of DNAZ·HClO4 were investigated under a non-isothermal condition by DSC and TG/DTG techniques. The results show that the thermal decomposition process of DNAZ·HClO4 has two mass loss stages. The kinetic model function in differential form, the value of apparent activation energy (Ea) and pre-exponential factor (A) of the exothermic decomposition reaction of DNAZ·HClO4 are f(α) = (1 − α)−1/2, 156.47 kJ mol−1, and 1015.12 s−1, respectively. The critical temperature of thermal explosion is 188.5 °C. The values of ΔS≠, ΔH≠, and ΔG≠of this reaction are 42.26 J mol−1 K−1, 154.44 kJ mol−1, and 135.42 kJ mol−1, respectively. The specific heat capacity of DNAZ·HClO4 was determined with a continuous Cp mode of microcalorimeter. Using the relationship between Cp and T and the thermal decomposition parameters, the time of the thermal decomposition from initiation to thermal explosion (adiabatic time-to-explosion) was evaluated as 14.2 s.
Authors:X. Han, Y. Sun, T. Wang, Zh. Lin, Sh. Li, F. Zhao, Z. Liu, J. Yi, and X. Ren
The effects of fullerenes, including fellerene soot (FS), extracted fullerene soot (EFS) and pure C60 on the thermal decomposition of ammonium perchlorate (AP) compared with traditional carbon black (CB) catalyst has been studied
by employing thermogravimetry (TG), differential thermal analysis (DTA), infrared spectroscopy (IR) and ignition temperature
experiments. The results showed that the addition of CB and FS to AP reduced the activation energy as well as the temperature
at maximum decomposition rate, but that of EFS and pure C60 had little effect on the thermal decomposition of AP, and among all catalysts, FS was the best one.
Authors:S. Hu, H. Shu, J.L. Yuan, J.Y. Gao, P.Y. Mu, C.Z. Ren, W. Sang, L.C. Guo, and H.B. Chen
The objective of this study was to evaluate the eﬀect of wheat–oat ﬂour ratio on the physical properties and β-glucan characteristics of extrudates. Results showed that increasing the wheat–oat ﬂour ratio resulted in a decrease in the water solubility index (r2=0.8567) and hardness (r2=0.9316), whereas the expansion ratio (r2=0.9307) and water absorption index (r2=0.9061) increased. Wheat ﬂour generally caused an increase in L values from 57.81 to 62.94 providing bright samples. Few cells were observed at high wheat–oat ﬂour ratios under a scanning electron microscope, and a smooth surface was noted. Meanwhile, the total (r2=0.9867) and soluble (r2=0.9848) β-glucan contents were inversely proportional to the wheat–oat ﬂour ratio. Extrudates with added wheat ﬂour had a high molecular weight, but wheat ﬂour had no signiﬁcant (P<0.05) eﬀect on the viscosity of β-glucan extracts. Conclusively, incorporation of wheat ﬂour at a wheat–oat ﬂour ratio of 2.33 provides ready-to-eat food based on whole oat ﬂour, on account of improving the texture and providing suﬃcient β-glucan contents (0.806 g/100 g) without signiﬁcantly aﬀecting β-glucan viscosity.
Two lines, L-19-613 and L-19-626, were produced from the common wheat cultivar Longmai 19 (L-19) by six consecutive backcrosses using biochemical marker-assisted selection. L-19 (Glu-D1a, Glu-A3c/Gli-A1?; Gli-A1? is a gene coding for unnamed gliadin) and L-19-613 (Glu-D1d, Glu-A3c/Gli-A1?) formed a set of near-isogenic lines (NILs) for HMW-GS, while L-19-613 and L-19-626 (Glu-D1d, Glu-A3e/Gli-A1m) constituted another set of NILs for the LMW-GS/gliadins. The three L-19 NILs were grown in the wheat breeding nursery in 2007 and 2008. The field experiments were designed using the three-column contrast arrangement method with four replicates. The three lines were ranked as follows for measurements of gluten strength, which was determined by the gluten index, Zeleny sedimentation, the stability and breakdown time of the farinogram, the maximum resistance and area of the extensogram, and the P andWvalues of the alveogram: L-19-613 > L-19-626 > L-19. The parameters listed above were significantly different between lines at the 0.05 or 0.01 level. The Glu-D1 and Glu-A3/Gli-A1 loci had additive effects on the gluten index, Zeleny sedimentation, stability, breakdown time, maximum resistance, area, P and W values. Although genetic variation at the Glu-A3/Gli-A1 locus had a great influence on wheat quality, the genetic difference between Glu-D1d and Glu-D1a at the Glu-D1 locus was much larger than that of Glu-A3c/Gli-A1? and Glu-A3e/Gli-A1m at the Glu-A3/Gli-A1 locus. Glu-D1d had negative effects on the extensibility and the L value compared with Glu-D1a. In contrast, Glu-A3c/Gli-A1? had a positive effect on these traits compared with Glu-A3e/Gli-A1m.