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A study on the catalytic performance of carbide slag in transesterification and the calculation of kinetic parameters

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Science China(Technological Sciences) 2015年第2期58卷 258-265页

作者： liu Meng Qi NIU sheng Li LU chun Mei LI Hui HUO Meng Jia School of Energy and Power Engineering Shandong University

The catalytic performance of carbide slag in transesterification is investigated and the reaction kinetic parameters are calculated. After being activated at 650℃, calcium compounds of carbonate and hydroxide in the carbide slag are mainly transformed into calcium oxide. The activated carbide slag utilized as the transesterification catalyst is characterized by X-ray diffraction （XRD）, attenuated total reflectance-Fourier transform infrared spectroscopy （ATR-FTIR）, nitrogen adsorption-desorption and the Hammett indicator method. Compared with the carbide slag activated at 700 and 800℃, the largest surface area of 22.63 m2g^-1, the smallest particle size of 265.12 nm and the highest catalytic efficiency of the carbide slag activated at 650℃ guarantee its capacity in catalyzing transesterification. Then, the influences of activated temperature （Ta）, molar ratio of methanol to oil （γ）, catalyst added amount （ζ）, reaction temperature （Tr） and reaction time （τ） on the catalytic performance are investi- gated. Under the optimal transesterification condition of Ta=650℃, γ=15, ζ=3%, Tr=60℃ and τ=-110 rain, the catalytic efficiency of 92.98% can be achieved. Finally, the kinetic parameters of transesterification catalyzed by the activated carbide slag are calculated, where activation energy （E） is 68.45 kJ mol^-1 and pre-exponential factor （k0） is 1.75×10^9 min^-1. The activated carbide slag shows better reused property than calcium hydroxide.

关键词： transesterification catalyst carbide slag kinetic parameters

Aboveground Biomass and Water Storage Allocation in Alpine Willow Shrubs in the Qilian Mountains in China

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Journal of Mountain Science 2015年第1期12卷 207-217页

作者： liu Zhang-wen CHEN Ren-sheng SONG Yao-xuan HAN chun-tan Qilian Alpine Ecology & Hrdrolody Research Station Key Laboratory of Ecohydrology of Inland River Basin Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences

The aboveground biomass allocation and water relations in alpine shrubs can provide useful information on analyzing their ecological and hydrological functions in alpine regions. The objectives of this study were to compare the aboveground biomass allocation, water storage ratio and distribution between foliage/woody components,and to investigate factors affecting aboveground biomass allocation and water storage ratio in alpine willow shrubs in the Qilian Mountains, China. Three experimental sites were selected along distance gradients from the riverside in the Hulu watershed in the Qilian Mountains. The foliage, woody component biomass, and water allocation of Salix cupularis *** Salix oritrepha Schneid. shrubs were measured using the selective destructive method. The results indicated that the foliage component had higher relative water and biomass storage than the woody component in the upper part of the crown in individual shrubs. However, the woody component was the major biomass and water storage component in the whole shrub level for S. cupularis and ***. Moreover, the foliage/woody component biomass ratio decreased from the top to the basal level of shrubs. The relative water storage allocation was significantly affected by species types, but was not affected by sites and interaction between species and sites. Meanwhile, relative water storage was affectedby sites as well as by interaction between sites and species type.

关键词： Water storage Aboveground biomass Alpine shrubs Willow Qilian Mountains

Reactive oxygen species metabolism during the cadmium hyperaccumulation of a new hyperaccumulator Sedum alfredii (Crassulaceae)

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Journal of Environmental Sciences 2007年第11期19卷 1311-1317页

作者： ZHANG Zhong-chun QIU Bao-sheng College of Life Sciences Huazhong Normal University Wuhan 430079 China

Sedum alfredii Hance, a newly discovered hyperaccumulator, could serve as a good material for phytoremediation of Cd polluted sites. Malondialdehyde （MDA）, reactive oxygen species （ROS） and antioxidases （catalase （CAT）; superoxide dismutase （SOD）; peroxidase （POD）） in the leaf were determined when S. alfredii was treated for 15 d with various CdC12 concentrations ranging from 0 to 800 μmol/L. The results showed that the production rate of 2＇,7＇-dichlorofluorescein （DCF）, which is an indicator of ROS level, reached up to the maximum at 400 μmol/L CdCl2 and then declined with the increase of CdCl2 concentration, while MDA accumulation tended to increase. CAT activity was significantly inhibited at all tested CdCl2 concentrations and SOD activity was sharply suppressed at 800 μmol/L CdCl2. However, the enhancement of POD activity was observed when CdCl2 concentration was higher than 400 μmol/L. In addition, its activity increased when treated with 600 μmol/L CdCl2 for more than 5 d. When sodium benzoate, a free radical scavenger, was added, S. alfredii was a little more sensitive to Cd toxicity than that exposed to Cd alone, and the Cd accumulation tended to decline with the increase of sodium benzoate concentration. It came to the conclusions that POD played an important role during Cd hyperaccumulation, and the accumulation of ROS induced by Cd treatment might be involved in Cd hyperaccumulation.

关键词： cadmium hyperaccumulation reactive oxygen species Sedum alfredii

Matter effects and coherent effect of neutrinos produced from γ-ray bursts

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Chinese Physics C 2019年第10期43卷 99-104页

作者： Kuan liu chun-sheng An Xin Li Hai-Nan Lin School of Physical Science and Technology Southwest UniversityChongqing 400715China Department of Physics Chongqing UniversityChongqing 401331China

Neutrinos produced from γ-ray bursts (GRBs) carry significant physical information. The electron density in the GRBs outflow is very large. In this study, we calculate the matter effect on neutrinos when they propagate through such a dense region. The average survival probability and the flavor ratio of neutrinos are determined. The ratio of resonant neutrino energy from different spherical shells provides the information of power index N for the power-law distribution of electrons in the hot fireball model. Electron density in the magnetic jet model is sufficiently lower than in the hot fireball model. The matter effect on neutrinos can be used to distinguish these two models. The coherent effect of strongly lensed PeV neutrinos is also discussed. The average survival probability of strongly-lensed electron neutrinos in the normal and inverted hierarchical cases are presented. The results show that this coherent effect can be used to determine the hierarchical mass of neutrinos.

关键词： neutrino oscillations γ-ray bursts gravitational lensing

Distribution and Estimation of Aboveground Biomass of Alpine Shrubs along an Altitudinal Gradient in a Small Watershed of the Qilian Mountains, China

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Journal of Mountain Science 2015年第4期12卷 961-971页

作者： liu Zhang-wen CHEN Ren-sheng SONG Yao-xuan HAN chun-tan Qilian Alpine Ecology & Hydrology Research Station Key Laboratory of Ecohydrology of Inland Basin Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences University of Chinese Academy of Sciences

Shrublands serve as an important component of terrestrial ecosystems, and play an important role in structure and functions of alpine *** estimation of biomass is critical to examination of the productivity of alpine ecosystems, due to shrubification under climate change in past *** this study, 14 experimental plots and 42 quadrates of the shrubs Potentilla fruticosa and Caragana jubata were selected along altitudes gradients from 3220 to 3650 m a.s.l.(above sea level) on semi-sunny and semi-shady slope in Hulu watershed of Qilian Mountains, *** foliage, woody component and total aboveground biomass per quadrate were examined using a selective destructive method, then the biomass were estimated via allometric equations based on measured parameters for two shrub *** results showed that *** accounted for 1–3 times more biomass(480.98 g/m2) than ***(191.21 g/m2).The aboveground biomass of both the shrubs varied significantly with altitudinal gradient(P<0.05).Woody component accounted for the larger proportion than foliage component in the total aboveground *** biomass on semi-sunnyslopes(200.27 g/m2 and 509.07 g/m2) was greater than on semi-shady slopes(182.14 g/m2 and 452.89g/m2) at the same altitude band for *** and *** contrast, the foliage biomass on semi-shady slopes(30.50 g/m2) was greater than on semi-sunny slopes(27.51 g/m2) for two *** deceased with increasing altitude for ***, whereas *** showed a hump-shaped pattern with *** equations were obtained from the easily descriptive parameters of height(H), basal diameter(D) and crown area(C) for biomass of *** and *** the equations type and variables comprising of the best model varied among the species, all equations related to biomass were significant(P < 0.005), with determination coefficients(R2) ranging from 0.81 to *** allometric equations satisfied the requirements of t

关键词： Aboveground biomass Allometric equations Alpine shrub Altitudinal gradient Qilian Mountains

Continuity of Solutions for Parametric Set Optimization Problems via Scalarization Methods

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Journal of the Operations Research Society of China 2021年第1期9卷 79-97页

作者： Pei-Pei liu Hong-Zhi Wei chun-Rong Chen sheng-Jie Li College of Mathematics and Statistics Chongqing UniversityChongqing 401331China

The aim of this paper is to investigate the continuity of solution mappings for para-metric set optimization problems with upper and lower set less order relations by scalarization ***,we recall some linear and nonlinear scalarization prop-erties used to characterize the set order ***,we introduce new monotonicity concepts of the set-valued mapping by linear and nonlinear scalarization ***,we obtain the semicontinuity and closedness of solution mappings for parametric set optimization problems(both convex and nonconvex cases)under the monotonicity assumption and other suitable *** results achieved do not impose the continuity of the set-valued objective mapping,which are obviously different from the related ones in the literature.

关键词： Upper semicontinuity Lowersemicontinuity Parametricset optimization problems Scalarization Monotonicity

Quantifying lateral penumbra advantages of collimated spot-scanning beam for intensity-modulated proton therapy

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Nuclear Science and Techniques 2019年第11期30卷 52-59页

作者： chun-Bo liu Yun-Tao Song Hong-Dong liu Hai-Zhou Xue Han-sheng Feng University of Science and Technology of China Hefei 230026China Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China Hefei CAS Ion Medical and Technical Devices Co. LtdHefei 230088China

Intensity-modulated proton therapy(IMPT)is becoming essential for proton therapy and is under rapid ***,for IMPT,the lateral penumbra of the spot-scanning proton beam is still an urgent issue to be ***-specific block collimators(PSBCs),which can block unnecessary doses,play a crucial role in passive scattering delivery technology but are rarely used in spot *** objective of this study is to investigate the lateral penumbra variations of intensity-modulated spot scanning with and without a *** fields with varying degrees of sharpness and at varying depths in a water phantom,the lateral penumbral widths were calculated using a Monte Carlo-based dose engine from RayStation *** results suggest that the lateral penumbral widths can be reduced by more than 30%for uniform target volumes,regardless of whether a range-shifter is used,and that the maximum dose beyond the field edges can be reduced *** results of patient cases show that the doses in organs-at-risk near the edge of the target volume decrease if a PSBC is *** study demonstrates that intensity-modulated spot scanning with a PSBC can effectively reduce the lateral penumbra and block unnecessary doses and is therefore promising for clinical applications in spot-scanning proton therapy.

关键词： Lateral penumbra Patient-specific block collimator Monte Carlo Intensity-modulated proton therapy

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正常结膜囊细菌培养397例分析

国际眼科杂志 2007年第1期7卷 117-120页

作者：曾树森吴晓梅宋建曾昌洪刘盛春四川大学华西医院眼科中国四川省成都市610041

目的:调查不同人群正常结膜囊带菌情况及其对常用抗生素的敏感情况。方法:对4wk内未使用滴眼液和抗生素的397名受调查者,常规眼科检查排除泪囊、眼表、前节疾病后,进行结膜囊细菌培养和药物敏感试验。结果:60岁人群结膜囊带菌率明显高... 详细信息

目的:调查不同人群正常结膜囊带菌情况及其对常用抗生素的敏感情况。方法:对4wk内未使用滴眼液和抗生素的397名受调查者,常规眼科检查排除泪囊、眼表、前节疾病后,进行结膜囊细菌培养和药物敏感试验。结果:60岁人群结膜囊带菌率明显高于12～60岁人群,农村高于城市。细菌培养阳性率为21.2%,共培养出13个菌种,84个菌株。葡萄球菌属最多,共54株(64.3%),其中表皮葡萄球菌43株(51.2%),金黄色葡萄球菌10株(11.9%)。革兰阳性细菌对万古霉素、呋喃坦啶、利福平敏感;大部分革兰阴性菌对复达欣、亚胺硫霉素、丁胺卡那霉素、妥布霉素敏感;对β-内酰胺类和喹诺酮类耐药菌株增多。结论:正常结膜囊可能带有细菌,并可致眼部感染。术前滴敏感抗生素眼液可减少结膜囊细菌,以防止眼部感染。

关键词：结膜囊细菌培养药物敏感试验

Fabrication of Carbon Nanotube-Reinforced 6061Al Alloy Matrix Composites by an In Situ Synthesis Method Combined with Hot Extrusion Technique

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Acta Metallurgica Sinica(English Letters) 2016年第2期29卷 188-198页

作者： chun-Nian He Chao Feng Ji-Chuan Lin En-Zuo liu chun-sheng Shi Jia-Jun Li Nai-Qin Zhao School of Materials Science and Engineering Tianjin KeyLaboratory of Composite and Functional MaterialsTianjin University Tianjin 300072 China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072 China Chengdu SIWI High-Tech Industry Co. Ltd Chengdu 611731 China

Carbon nanotube （CNT）-reinforced 6061Al alloy matrix composites were prepared by chemical vapor depo- sition （CVD） combined with hot extrusion technique. During the preparation process, the 6061Al flakes obtained by ball milling of the 6061Al spherical powders were subjected to surface modification to introduce a hydrophilic polyvinyl alcohol （PVA） membrane on their surface （6061Al@PVA） to bond strongly with nickel acetate [Ni（II）]. Then the 6061Al@PVA flakes bonded with Ni（II） were calcined and reduced to Ni nanoparticles, which were then heat-treated at 580 ℃ to remove PVA for obtaining even Ni/6061Al catalyst. After that, the as-obtained Ni/6061Al catalyst was employed to synthesize CNTs on the surface of the 6061Al flakes by CVD. After hot extrusion of the CNT/6061Al composite powders, the as-obtained CNT/6061Al bulk composites with 2.26 wt% CNTs exhibited 135% increase in yield strength and 84.5% increase in tensile strength compared to pristine 6061Al matrix.

关键词： Metal matrix composites (MMCs) Microstructure Mechanical properties Carbon