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Abstract  

A dual cell system was used to study the electrogenerative leaching sphalerite-MnO2 under the conditions of presence and absence of Acidithiobacillus ferrooxidans (A. ferrooxidans). The polarization of anode and cathode, and the relationship between the electric quantity (Q) and some factors, such as the dissolved Zn2+, Fe2+, the time in the bio-electro-generating simultaneous leaching (BEGSL) and electro-generating simultaneous leaching (EGSL), were studied. The results show that the dissolved Zn2+ in the presence of A. ferrooxidans is nearly 60% higher than that in the absence of A. ferrooxidans; the electrogenerative quantity in the former is about 134% more than that in the latter. A three-electrode system was applied to study anodic and cathodic self-corrosion current, which was inappreciable compared with the galvanic current between sphalerite and MnO2. The accumulated sulfur on the surface of sulfides produced in the electrogenerative leaching process could be oxidized in the presence of A. ferrooxidans, and the ratio of biological electric quantity reached to 31.72% in 72 h.

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Abstract

The thermal decomposition behavior of composite modified double-base propellant containing hexanitrohexaazaisowurtzitane (CL-20/CMDB propellant) was studied by microcalorimetry. The kinetic and thermodynamic parameters were obtained from the analysis of the heat flow curves. The effect of different proportion of CL-20 to the thermal decomposition behavior, kinetics, and thermal hazard was investigated at the same time. The critical temperature of thermal explosion (T b), the self acceleration decomposition temperature (T SADT), and the adiabatic decomposition temperature rise (ΔT ad) were calculated to evaluate the thermal hazard of the CL-20/CMDB propellant. It shows that the CMDB propellant with 38% CL-20 has relative lower values of E and lgA, and with 18% CL-20 has the highest potential hazard.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
Li Gaoliang
,
He Hui
,
Zheng Weifang
,
Tang Hongbin
,
Li Huirong
,
Lan Tian
,
Liu Xiechun
,
Zhang Hu
,
Yang He
,
Luo Fangxiang
,
Xiao Songtao
, and
Ye Guoan

Abstract  

Oxidation of Pu(III) in 1 bp solution to Pu(IV) was studied using the salt-free oxidant N2O4. It was proved that the reductants N,N-dimethylhydroxylamine (DMHAN) and monomethyl-hydrazine (MMH) present in 1 bp solution of CIAE-APOR process can be oxidized and removed from the solutions also by N2O4 before the oxidation of Pu(III). The effects of the acidity, the temperature and the amount of N2O4 added on the oxidation of DMHAN and MMH were studied.

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Acta Chromatographica
Authors:
Long Wang
,
Yuan-Yuan Jiang
,
Li Zhang
,
Tao Wang
,
Rui-Wu Yang
,
Chun-Bang Ding
,
Xiao-Li Wang
, and
Yong-Hong Zhou

A high-performance liquid chromatography (HPLC) method has been developed for the simultaneous identification and quantification of active compounds (cryptotanshinone, dihydrotanshinone I, tanshinone IIA, tanshinone I, salvianolic acid A, salvianolic acid B, protocatechuic aldehyde, and rosmarinic acid) contained in traditional Chinese folk medicine Salvia przewalskii Maxim. The herb samples (including wild, cultivated, and yin pian) from fourteen main regions were investigated. Chromatographic separation was performed on an Agilent Eclipse XDB-C18 reserved-phase column (250 mm × 4.6 mm i.d., 5 μm) using gradient elution with water-formic acid (99.9: 0.1, v/v) and acetonitrile at a flow rate of 0.8 mL min−1, an operating temperature of 30 °C, and a wavelength of 275 nm. Similarity analysis (SA), principal component analysis (PCA), and hierarchical cluster analysis (HCA) were used to analyze the data based on fingerprints. For fingerprint analysis, 27 peaks were selected as the common peaks to evaluate the similarities among different samples. The results of SA showed that the method permits to obtain desired linearity, precision, accuracy, and recovery. All samples were divided into three categories by PCA and HCA, and the concentration of the eight bioactive compounds varied significantly from different regions. It was demonstrated that chromatographic fingerprinting by HPLC combined with the simultaneous determination of eight bioactive compounds was a helpful method for the quality control of S. przewalskii.

Open access

Abstract

Benzoyl peroxide (BPO) has been widely used in the industrial and food field, it is sensitive to shock, heat and friction, and causes thermal explosion incidents easily. Therefore, it is important to understand its thermal behaviors and kinetics for loss prevention and safety management. Two kinds of experimental methods (C80 calorimetry and accelerating rate calorimetry) were used to study the hazardous characteristics of BPO, and idea kinetic parameters, such as the pre-exponential factor and the activation energy were obtained. These results contribute to improve the safety in the reaction, transportation, and storage processes and help to the stability criterion of decomposition reaction of BPO.

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Abstract  

A series of lanthanum-promoted Pd/Al2O3 catalysts (Pd/La x –Al2O3), for the liquid phase in situ hydrogenation of phenol into cyclohexanone, was prepared by the incipient wetness impregnation method. Addition of lanthanum to Pd/Al2O3 enhances the TOF of the catalyst for the liquid phase in situ hydrogenation of phenol significantly. The conversion of phenol is highly dependent upon the atomic ratio of La/Pd, but the presence of lanthanum has little effect on the selectivity of cyclohexanone. The selectivity of cyclohexanone in the liquid phase in situ hydrogenation of phenol over the Pd/La x –Al2O3 catalyst is as high as 98%, which is quite higher than the hydrogenation using H2 (67.4%). Results from BET, EDS, CO chemosorption, XRD and H2-TPR suggest that the presence of suitable amounts of lanthanum improves the Pd dispersion on the support. The peak temperature for the reduction of PdO in the H2-TPR moves to higher in the presence of lanthanum. Additionally, the Pd particles could adhere to the lanthanum rather than the Al2O3.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
Xiao-Ying Li
,
Yong Ren
,
Xue-Jiao Chen
,
Da-Yong Qiao
, and
Wei-Zheng Yuan

Abstract  

The design, fabrication, and testing of a 4H-SiC Schottky betavoltaic nuclear battery based on MEMS fabrication technology are presented in this paper. It uses a Schottky diode with an active area of 3.14 mm2 to collect the charge from a 4 mCi/cm2 63Ni source. Some of the critical steps in process integration for fabricating silicon carbide-based Schottky diode were addressed. A prototype of this battery was fabricated and tested under the illumination of the 63Ni source with an activity of 0.12 mCi. An open circuit voltage (V OC) of 0.27 V and a short circuit current density (J SC) of 25.57 nA/cm2 are measured. The maximum output power density (P max) of 4.08 nW/cm2 and power conversion efficiency (η) of 1.01% is obtained. The performance of this battery is expected to be significantly improved by using larger activity and optimizing the design and processing technology of the battery. By achieving comparable performance with previously constructed p–n or p–i–n junction energy conversion structures, the Schottky barrier diode proves to be a feasible approach to achieve practical betavoltaics.

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Biologia Futura
Authors:
Fahar Ibtisham
,
Yi Zhao
,
Jiang Wu
,
Aamir Nawab
,
Xiao Mei
,
GuangHui Li
, and
Lilong An

Introduction

The ability for isolation and in vitro propagation of spermatogonial stem cells (SSCs) offer a base for studies on spermatogenesis, and also contribute to the development of new methods for the preservation of livestock and animal genetic modification. The aim of this study was to find the optimal isolation and culture condition for efficient propagation of SSCs.

Methods

Three different isolation methods (mechanical, one-, and two-step enzymatic digestion) were compared to find the optimal isolation method. To find the best culture conditions for in vitro propagation, isolated SSCs were cultured for 7 days in three different culture conditions supplemented with 10% FBS, 0.25% BSA, and 10% KSR, respectively.

Results

The result showed that two-step enzymatic digestion produced a significant high fraction of live cells compared the other two. Non-adhering cells collected after 48 hr and cultured in BSA- and KSR-supplemented medium had a significantly high number of SSCs clump formation compared to FBS-supplemented group. The expression of CD9 confirmed that cell clumps were SSCs clumps. Spermatogonial stem cells cultured in BSA-supplemented medium were positive for NGN3 and PLZF expressions, whereas negative for Stra8 (a meiotic-specific gene) expression, suggesting that most of the cells were undifferentiated SSCs in BSA culture system. In contrast, in FBS- and KSR-supplemented groups, the SSCs were positive for NGN3, PLZF, and Stra8.

Conclusion

These data revealed that two-step enzymatic digestion is the best method for the isolation, and 0.25% BSA-supplemented culture condition is effective for optimal in vitro propagation of SSCs.

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A simple and rapid high-performance liquid chromatographic (HPLC) method was established for simultaneous determination of butorphanol tartrate and ondansetron hydrochloride in analgesic mixture samples used for patient-controlled analgesia (PCA). The separation of butorphanol tartrate and ondansetron hydrochloride in PCA solution was carried out on phenomenex C18 column (4.6 mm × 150 mm, 5 μm) using 50 mM sodium acetate (pH 4.0) buffer and acetonitrile (72:28, v/v). Flow rate was 1.0 mL min−1 with a column temperature of 30 °C, and detection wavelength was carried out at 280 nm and 306 nm. Validation of the method was made in terms of specificity, linearity, accuracy, and intra- and inter-day precision, as well as quantification and detection limits. The developed method was successfully used to evaluate the chemical stability of butorphanol tartrate and ondansetron hydrochloride in analgesic mixtures at the usual concentration used for PCA.

Open access
Journal of Radioanalytical and Nuclear Chemistry
Authors:
Shengyun Zhu
,
Yongnan Zheng
,
Yi Zuo
,
Dongmei Zhou
,
Daqing Yuan
,
Anli Li
,
Zhiqiang Wang
,
Xiao Duan
,
Meng Liu
, and
Yong Li

Abstract  

The perturbed angular correlation (PAC) and positron annihilation spectroscopy (PAS) that use nuclear probes to characterize the micro-structure of materials are briefly described. Three examples are given to show their partial applications. The first example is the study of radiation damage in Si irradiated by fast neutrons of 1.45·1020 cm−2 and 178W heavy ions of 5·1011 cm−2, respectively. The PAC and PAS measurements all show that the monovacancy-oxygen complexes and divacancies and divacancy-oxygen complexes were produced by the irradiations, and quadrivacancies and quadrivacancy-oxygen complexes were formed during thermal annealing. The second one illustrates the investigation of high T c superconductivity for YBaCuO. The PAS experiment found the charge transfer during the superconducting trasition. The PAC measurement suggested a transition of two-to one-dimensional Cu-O-Cu chain structure at the superconducting trasition temperature T c , which favors the charge transfer from the CuO layer to the CuO chain in YBaCuO. The third one is for investigating the hydrogen behavior in Pd0.75Ag0.25-H x as functions of temperature from 77 K to RT and hydrogen concentration (x) from 0 to 35 at.%. The PAC and PAS results exhibit that hydrogen atoms are congregated into the hydrogen bubbles and the hydrogen bubbles grow with the increasing of the hydrogen concentration in Pd0.75Ag0.25-H x . These examples demonstrate that the PAC and PAS techniques are very sensitive and powerful tools in materials science, which can well investigate phenomena in materials on atomic scale.

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