检索结果-南通市图书馆

Biodesulfurization of vanadium-bearing titanomagnetite concentrates and pH control of bioleaching solution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2013年第10期20卷 925-930页

作者： Xiao-rong Liu Sheng-cai Jiang Yan-jun Liu Hui Li hua-jun wang School of Materials Science and Engineering Shanghai Institute of Technology China Metallurgical Mining Corporation Civil and Environmental Engineering School University of Science and Technology Beijing

Vanadium-bearing titanomagnetite concentrates were desulfurized with Acidithiobacillus ferrooxidans （A. ferrooxidans）. The sulfur content of the concentrates was reduced from 0.69wt% to 0.14wt% after bioleaching for 15 d with a 10% pulp density at 30℃. Maintaining a stable pH value during biodesulfurization was critical because of high acid consumption, resulting from a combination of nonoxidative and oxidative dissolution of pyrrhotite in acid solution. It is discovered that the citric acid-disodium hydrogen phosphate buffer of pH 2.0 can control the solution pH value smoothly in the optimal range of 2.0-3.0 for A. ferrooxidans growth. Using the buffer in the volume fraction range of 5.0%-15.0% stimulates A. ferooxidans growth and improves the biodesulfurization efficiency. Compared with the buffer-free control case, the maximum increase of biodesulfurization rate is 29.7% using a 10.0vol% buffer. Bioleaching provides an alternative process for desulfurization of vanadium-bearing titanomagnetite ores.

关键词： titanomagnetite vanadium biodesulfurization Acidithiobacillus ferrooxidans citric acid disodium hydrogenphosphate

Testosterone level and mortality in elderly men wit systolic chronic heart failure

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2011年第5期13卷 759-763页

作者： Hai-Yun Wu Xiao-Fei wang jun-hua wang Jiang-Yuan Li Institute of Geriatric Cardiology Chinese PLA General Hospital Beijing 100853 China Department of Cardiology the 306th Hospital of Chinese PLA Beijing 100101 China Department of Cardiology Chinese PLA Aifforce General Hospital Beijing 100036 China Department of Endocrinology Chinese PLA General Hospital Beijing 100853 China

Previous studies on the prognostic significance of serum levels of androgens in patients with chronic heart failure （CHF） have yielded conflicting results. The aim of this study was to examine the relationship between serum concentration of testosterone and mortality in men with systolic CHF. A total of 175 elderly men （age ≥60 years） with CHF were recruited. Total testosterone （TI＇） and sex hormone-binding globulin （SHBG） were measured, and estimated free testosterone （eFT） was calculated. The median follow-up time was 3.46 years. Of these patients, 17 had a TT level below 8 nmol I^-1 （230 ng dI^-1）, 27 had an eFT level below 0.225 nmol I^-1 （65 pg ml^-1） and 12 had both. Using the age-specific tenth percentiles of TT and eFT in healthy men in our laboratory as cutoff points, the prevalences of TT and eFT deficiency was 21.7% （38/175） and 27.4% （48/175）, respectively. Both TT and eFT were inversely associated with left ventricular ejection fraction （LVEF） and N-terminal pro-brain natriuretic peptide （NT-pro-BNP）（all P〈0.01）. Kaplan-Meier curves for patients in low, medium and high tertiles according to TT and eFT level showed significantly different cumulative survival rate （both P〈0.01 by log-rank test）. However, after adjustment for clinical variables, there were no significant associations of either TT or eFT levels with survival time （0R=0.97, 95% CI： 0.84-1.12, P=0.28 and 0R=0.92, 95% CI： 0.82-1.06, P=0.14, respectively）. Our study showed that levels of TT and eFT are commonly decreased in elderly patients with systolic CHF and related to disease severity, but they are not independent predictors for mortality.

关键词： free testosterone heart failure prognosis total testosterone

Recovery of iron and copper from copper tailings by coal-based direct reduction and magnetic separation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2017年第10期24卷 991-997页

作者： Chao Geng hua-jun wang Wen-tao Hu Li Li Cheng-shuai Shi School of Civil and Resource Engineering University of Science and Technology Beijing Key Laboratory for Solid Waste Management and Environment Safety Ministry of Education of ChinaSchool of EnvironmentTsinghua University

A technique comprising coal-based direct reduction followed by magnetic separation was presented to recover iron and copper from copper slag flotation *** process parameters,such as reductant and additive ratios,reduction temperature,and reduction time,were experimentally determined and found to be as follows：a limestone ratio of 25%,a bitumite ratio of 30%,and reduction roasting at 1473 Kfor 90 *** these conditions,copper-bearing iron powders（CIP）with an iron content of 90.11% and copper content of 0.86%,indicating iron and copper recoveries of87.25% and 83.44%respectively,were effectively *** electron microscopy and energy dispersive spectroscopy of the CIP revealed that some tiny copper particles were embedded in metal iron and some copper formed alloy with iron,which was difficult to achieve the separation of these two ***,the copper went into magnetic products by magnetic *** copper into the steel can produce weathering ***,the CIP can be used as an inexpensive raw material for weathering steel.

关键词： Copper slag Coal-based direct reduction Magnetic separation Iron powder Weathering steel

Correlation between aggregation structure and tailing mineral crystallinity

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2014年第9期21卷 845-850页

作者： Wen-tao Hu Xin-wei Li hua-jun wang Chuan-yao Sun Xu-qin Duan State Key Laboratory of the Ministry of Education of China for High-Efficient Mining and Safety of Metal Mines University of Science and Technology Beijing School of Civil and Environmental Engineering University of Science and Technology Beijing State Key Laboratory of Mineral Processing Science and Technology Beijing General Research Institute of Mining and Metallurgy

Direct reduction is an emerging technology for the utilization of refractory iron ore. With this technology, iron oxides in the ore can be reduced to recoverable elemental iron. The structure of granular aggregates in direct reduction products was investigated by X-ray diffraction （XRD）. The results show that iron is mainly generated as a shell in the outer edge of the aggregates. The thermal conductivity of the iron shell is higher than that of other minerals. Thus, minerals close to the iron shell cool faster than those in the inner shells and do not crystallize well. These minerals mainly become stage 2 tailings. Hence the XRD intensity of stage 2 tailings is lower than that of stage 1 tailhags. When iron is mainly generated in the interior of the aggregates, the crystallinity of stage 2 tailings will be higher than that of stage 1 tailings. This indicates that the crystallinity of tailings can be used as a marker for the aggregate structure.

关键词： iron ore reduction aggregation crystallinity railings

Numerical modelling of the dynamic process of oil displacement by water in sandstone reservoirs with random pore structures

在线全文

学校读者我要写书评

暂无评论

Journal of Groundwater Science and Engineering 2021年第3期9卷 233-244页

作者： Fei Gao Feng Liu hua-jun wang School ofEnergy and Environment Engineering Hebei University of TechnologyTianjin 300401China. Institute of Hydrogeology and Environment Geology Chinese Academy of Geological SciencesShijiazhuang 050061China. Technology Innovation Center of Geothermal&Hot Dry Exploration and Development Ministry of Natural ResourcesShijiazhuang 050061China. China University of Geosciences(Beijing) Beijing 100000China.

The study aims to identify a suitable site for open and bore well in a farmhouseusing ground magnetic survey in south *** also aims to define depth to granitoid and structural elements which traverse the selected *** data(n=84)measured,processed and interpreted as qualitative and *** results of total magnetic intensities indicate that the area is composed of linear magnetic lows trending NE-SW direction and circular to semi-circular causative *** magnetic values ranged from-137 nT to 2345 nT with a mean of 465 *** to equator shows significant shifting of causative bodies in the southern and northern *** signal map shows exact boundary of granitic *** directional filter has brought out structural element trending NE-SW *** of individual profile brought to light structurally weak zone between 90 m and 100 m in all the profile *** decrease of magnetic values from 2042 nT to 126 nT noticed in profile line 6 between 20 m and 30 m indicates fault *** breaks obtained from these maps were visualized,interpreted and identified two suitable sites for open and bore *** averaged power spectrum estimates depth of shallow and deep sources in 5 m and 50 m,*** method has also been applied to estimate depth of granitoid and structural elements using structural indexes 0,1,2,and 3 and found depth ranges from90 *** indicates magnetic method is one of the geophysical methods suitable for groundwater exploration and site selection for open and borewells.

关键词： Sandstone reservoirs Random pores Random generation-growth algorithm Oil-water displacement Displacement efficiency

A Novel Stereoseletive Approach to (E)-Vinylic Selenides

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1999年第6期10卷 437-440页

作者： jun hua wang Xian huaNG(Department of Chemistry. Zhejiang University(Campus Xixi). Hangzhou 310028) Zhejiang Univ Dept Chem Hangzhou 310028 Peoples R China

The insertion of elemental selenium into the Csp(2)-Zr bond of alkenylchloro-zirconocenes affords (E)-vinylseleno zirconocenes, which were trapped by alkyl halides giving (E)-vinylic selenides in moderate to good yields.

关键词： hydrozirconation reaction insertion vinylseleno zirconocenes vinylic selenides

A Stereoselective Approach to S-Vinyl Thioesters from Alkynes,Elemental Sulfur and Acyl Chlorides

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2000年第1期11卷 1-2页

作者： jun hua wang Qing Xu Xian huaNG Department of Chemistry, Zhejiang University (Campus Xixi), Hangzhou 310028 Zhejiang Univ Dept Chem Hangzhou 310028 Peoples R China

A facile, stereoselective synthesis of S-vinyl thioesters from easily available starting compounds and reagents is showed.

关键词： S-vinyl thioesters hydrozirconation

Commentary: A nearly forgotten class of anti-inflammatory lipid molecules in central nervous system

在线全文

学校读者我要写书评

暂无评论

Acta Pharmaceutica Sinica B 2023年第6期13卷 2809-2811页

作者： Nan Ru Wan-Yang Sun hua-jun wang Yan-Ping Wu Xiao-Fei Zheng Rong-Rong He The First Affiliated Hospital/International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education(MOE)/Guangdong Engineering Research Center of Chinese Medicine&Disease Susceptibility/Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research Jinan UniversityGuangzhou 510632China State Key Laboratory of Quality Research in Chinese Medicine Macao University of Science and TechnologyMacaoChina

Lipids are the major components of cells in the central nervous system(CNS) and are essential for the brain development and homeostasis. Several studies have demonstrated that impaired lipid metabolism is closely related to neurological diseases among the elderly^(1). Lipidomics can serve us well in identifying and quantifying lipid molecules in cells, tissues, and organisms at the system level. However, finding out biologically meaningful lipids from the massive lipidomics data is not straightforward.

关键词： Lipidomics Aging 3-Sulfogalactosyl diacylglycerols Anti-inflammation Central nervous system

Mesenchymal stem cell-derived exosomes inhibit the VEGF-A expression in human retinal vascular endothelial cells induced by high glucose

在线全文

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2021年第12期14卷 1820-1827页

作者： Guang-Hui He Ying-Xue Ma Meng Dong Song Chen Yu-Chuan wang Xiang Gao Bin Wu Jian wang jun-hua wang Clinical College of Ophthalmology Tianjin Medical UniversityTianjin 300070China Tianjin Eye Hospital Tianjin Eye InstituteTianjin Key Lab of Ophthalmology and Visual ScienceTianjin 300020China Ophthalmic Center of Xinjiang Production and Construction Corps Hospital Urumqi 830002Xinjiang Uygur Autonomous RegionChina Medical College of NanKai University Tianjin 300000China

AIM:To determine the effect of exosomes derived from human umbilical cord blood mesenchymal stem cells(hUCMSCs)on the expression of vascular endothelial growth factor A(VEGF-A)in human retinal vascular endothelial cells(HRECs).METHODS:Exosomes were isolated from hUCMSCs using cryogenic ultracentrifugation and characterized by transmission electron microscopy,Western blotting and nanoparticle tracking *** were randomly divided into a normal control group(group A),a high glucose model group(group B),a high glucose group with 25μg/mL(group C),50μg/mL(group D),and 100μg/mL exosomes(group E).Twenty-four hours after coculture,the cell proliferation rate was detected using flow cytometry,and the VEGF-A level was detected using *** coculture 8,16,and 24h,the expression levels of VEGF-A in each group were detected using PCR and Western ***:The characteristic morphology(membrane structured vesicles)and size(diameter between 50 and 200 nm)were observed under transmission electron *** average diameter of 122.7 nm was discovered by nanoparticle tracking analysis(NTA).The exosomal markers CD9,CD63,and HSP70 were strongly *** proliferation rate of the cells in group B increased after 24h of *** analyses revealed that the upregulation of VEGF-A expression in HRECs stimulated by high glucose could be downregulated by cocultured hUCMSC-derived exosomes(F=39.03,P<0.01).The upregulation of VEGF-A protein(group C:F=7.96;group D:F=17.29;group E:F=11.89;8h:F=9.45;16h:F=12.86;24h:F=42.28,P<0.05)and mRNA(group C:F=4.137;group D:F=13.64;group E:F=22.19;8h:F=7.253;16h:F=16.98;24h:F=22.62,P<0.05)in HRECs stimulated by high glucose was downregulated by cocultured hUCMSC-derived exosomes(P<0.05).CONCLUSION:hUCMSC-derived exosomes downregulate VEGF-A expression in HRECs stimulated by high glucose in time and concentration dependent manner.

关键词： mesenchymal stem cells exosomes retinal vascular endothelial cells vascular endothelial growth factor A coculture