检索结果-南通市图书馆

Microstructure Characteristic and Phase Evolution of Refractory Siderite Ore during Sodium-carbonate-added Catalyzing Carbothermic Reduction

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 2016年第9期23卷 891-899页

作者： shao-jun bai Meng WU Chao LU Shu-ming WEN State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Kunming 650093Yunnan China Faculty of Land Resource Engineering Kunming University of Science and Technology Kunming 650093 Yunnan China

Thermodynamic analysis of refractory siderite ore during carbothermic reduction was conducted. Micro- structure characteristics and phase transformation of siderite ore during sodium-carbonate-added catalyzing carboth- ermic reduction were investigated. X-ray diffraction （XRD）, scanning electron microscopy and energy-dispersive analysis of X rays were used to characterize the reduced samples. Results indicate that the solid reaction between FeO and SiO2 is inevitable during carbothermic reduction and the formation of fayalite is the main hindrance to the rapid reduction of siderite. The phase transformation of present siderite ore can be described as： siderite-magnetite-metallic iron, complying with the formation of abundant fayalite. Improving the reduction temperature （-1050 -C ） and duration is helpful for the formation and aggregation of metallic iron. The iron particle size in the reduced ore was below 20 l-m, and fayalite was abundant in the absence of sodium carbonate. With 5% Na2CO3 addition, the iron particle size in the reduced ore was generally above 50μm, and the diffraction intensity associated with metallic iron in the XRD pattern increased. The Na2O formed from the dissociation of Na2 CO3 can catalyze the carbothermie reduction of the siderite. This catalytic activity may be mainly caused by an increase in the reducing reaction activity of FeO.

关键词： siderite ore microstructure characteristic phase evolution catalyzing carbothermie reduction

First-principle study on the surface atomic relaxation properties of sphalerite

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2012年第9期19卷 775-781页

作者： Jian Liu Shu-ming Wen Yong-jun Xian shao-jun bai Xiu-min Chen Faculty of Land Resource Engineering Kunming University of Science and Technology Kunming 650093 China National Engineering Laboratory of Vacuum Metallurgy Kunming University of Science and Technology Kunming 650093 China

The surface properties of sphalerite （ZnS） were theoretically investigated using first principle calculations based on the density functional theory （DFT）. DFT results indicate that both the （110） and the （220） surfaces of sphalerite undergo surface atom relaxation after geometry optimization, which results in a considerable distortion of the surface region. In the normal direction, i.e., perpendicular to the sur- face, S atoms in the first surface layer move outward from the bulk （dl）, whereas Zn atoms move toward the bulk （d2）, forming an S-enriched surface. The values of these displacements are 0.003 nm for dl and 0.021 nm for d2 on the （110） surface, and 0.002 nm for dl and 0.011 nm for d2 on the （220） surface. Such a relaxation process is visually interpreted through the qualitative analysis of molecular mechanics. X-ray photoelectron spectroscopic （XPS） analysis provides the evidence for the S-enriched surface. A polysulphide （S n^2- ） surface layer with a bind- ing energy of 163.21 eV is formed on the surface of sphalerite after its grinding under ambient atmosphere. This S-enriched surface and the S 2- surface layer have important influence on the flotation properties ofsphalerite. Keywords：

关键词： sphalerite surface relaxation density fimctional theory froth flotation

Evolution of pore systems in low-maturity oil shales during thermal upgrading--Quantified by dynamic SEM and machine learning

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第3期21卷 1739-1750页

作者： jun Liu Xue bai Derek Elsworth Key Laboratory of Deep Underground Science and Engineering(Ministry of Education) Institute of New Energy and Low-Carbon TechnologySichuan UniversityChengdu610065SichuanChina International Quantum Academy Shenzhen518048GuangdongChina Shenzhen Institute of Advanced Electronic Materials Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen518055GuangdongChina Department of Energy and Mineral Engineering Pennsylvania State University ParkPA 16802USA

In-situ upgrading by heating is feasible for low-maturity shale oil,where the pore space dynamically *** characterize this response for a heated substrate concurrently imaged by *** systematically follow the evolution of pore quantity,size(length,width and cross-sectional area),orientation,shape(aspect ratio,roundness and solidity)and their anisotropy—interpreted by machine *** indicate that heating generates new pores in both organic matter and inorganic ***,the newly formed pores are smaller than the original pores and thus reduce average lengths and widths of the bedding-parallel pore ***,the average pore lengths and widths are increased in the bedding-perpendicular ***,heating increases the cross-sectional area of pores in low-maturity oil shales,where this growth tendency fluctuates at300℃.In addition,the orientation and shape of the newly-formed heating-induced pores follow the habit of the original pores and follow the initial probability distributions of pore orientation and ***,limited anisotropy is detected in pore direction and shape,indicating similar modes of evolution both bedding-parallel and *** propose a straightforward but robust model to describe evolution of pore system in low-maturity oil shales during heating.

关键词： Low-maturity oil shale Pore elongation Organic matter pyrolysis In-situthermal upgrading Scanning electron microscopy(SEM) Machine learning

Palaeoceanological significance of Holocene ostracean banks in Tianjin area

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 1991年第2期10卷 249-262页

作者： Wang Qiang, Li Xiuwen, Zhang Zhiliang, Li Fenglin, shao jun, bai Dezhong, Shang Xuexi and Tang Ruolu(Received October 24, 1990 accepted November 14, 1990)

On the basis of the study of ostracean banks in Tianjin area, the present study recognized that the ostracean banks at Ninghe County in Tianjin area are well developed along the west coast of the Bohai Sea; they consist of thanato-coenose and taphocoenose from Crassistrea gigars and C. revularis. From the 14C datings it can be known that the banks had formed from early Middle-Holocene and continued up to over 2 ka BP (14C age). The top has different reliefs . Although there is an effect of spatial shift of estuary position, the top is only distributed in the range of-0. 50--2. 50 m(Huanghai elevation minus National elevation system). The banks cannot explain the sea-level fluctuation. As the string ostracean banks are distributed near E-W direction, it suggests that the direction of tidal currents was then similar to that of the present day.

关键词： Palaeoceanological significance of Holocene ostracean banks in Tianjin area

A GMM approach in coupling internal data and external summary information with heterogeneous data populations

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2024年第5期67卷 1115-1132页

作者： jun shao Jinyi Wang Lei Wang Key Laboratory of Advanced Theory and Application in Statistics and Data Science(East China Normal University) Ministry of EducationShanghai 200062China School of Statistics East China Normal UniversityShanghai 200062China Department of Statistics University of Wisconsin-MadisonWI 53706USA School of Statistics and Data Science KLMDASRLEBPS and LPMCNankai UniversityTianjin 300071China

Because of advances in data collection and storage,statistical analysis in modern scientific research and practice now has opportunities to utilize external information such as summary statistics from similar studies.A likelihood approach based on a parametric model assumption has been developed in the literature to utilize external summary information when the populations for external and main internal data are assumed to be the *** this article,we instead consider the generalized estimation equation(GEE)approach for statistical inference,which is semiparametric or nonparametric,and show how to utilize external summary information even when internal and external data populations are not the *** approach is coupling the internal data and external summary information to form additional estimation equations and then applying the generalized method of moments(GMM).We show that the proposed GMM estimator is asymptotically normal and,under some conditions,is more efficient than the GEE estimator without using external summary *** of the asymptotic covariance matrix of the GMM estimators are also *** results are obtained to confirm our theory and quantify the improvements by utilizing external *** example is also included for illustration.

关键词： adjustment for heterogeneity constraint data integration generalized method of moments summarystatistic

Investigation of HO_(2) uptake mechanisms onto multiple-component ambient aerosols collected in summer and winter time in Yokohama,Japan

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第3期137卷 18-29页

作者： jun Zhou Yukiko Fukusaki Kentaro Murano Tania Gautam Yu bai Yoshimi Inomata Hiroaki Komatsu Mayuko Takeda Bin Yuan Min shao Yosuke Sakamoto Yoshizumi Kajii Institute for Environmental and Climate Research Jinan UniversityGuangzhou 511443China Guangdong-Hongkong-Macao Joint Laboratory of Collaborative Innovation forEnvironmental Quality Guangzhou 511443China Graduate School of Global Environmental Studies Kyoto UniversityKyoto606-8501Japan Yokohama Environmental Science Research Institute Yokohama Kanagawa 221–0024Japan Department of Chemistry University of AlbertaAlbertaEdmonton T6G 2G2Canada Graduate School of Human and Environmental Studies Kyoto UniversityKyoto 606-8501Japan Kanagawa Environmental Research Center Kanagawa 254-0014Japan Center for Regional Environmental Research National Institute for Environmental StudiesIbaraki305-8506Japan

The heterogeneous loss of HO_(2)radicals onto ambient aerosols plays an important role in tropospheric ***,sparse investigation of the dominating parameters controlling the HO_(2)uptake coefficients onto ambient aerosols(γHO_(2))has largely hindered the application of the measuredγHO_(2)to the global spatial *** we induced an offine method using LFP-LIF technique to measure the kinetics of HO_(2)uptake onto ambient aerosols collected in summertime and wintertime in Yokohama city,a regional urban site near Tokyo,*** controlling the dominating parameters which infuenceγHO_(2),we were able to investigate the detailed HO_(2)uptake *** characterized the chemical composition of the collected ambient aerosols,including organics,inorganics,transition metals ions,*** modeledγHO_(2)using different *** show thatγHO_(2)increased with the increase in RH,and the aerosol states(“dry”or wet/aqueous)have large effects onγHO_(2).With fixed RH and aerosol chemical composition,γHO_(2)was highly dependent on pH and inversely correlated with[HO_(2)]_*** combing the measuredγHO_(2)values with the modeled ones,we found that both the HO_(2)self-reaction and transition metal-catalyzed reactions should be accounted for to yield a single parameterization to predictγHO_(2),and different chemical compositions may have collective effects onγHO_(2).Results may serve for extending theγHO_(2)values measured at one observation site to different environmental conditions,which will help us to achieve more accurate modeling results concerning secondary pollutant formation(i.e.,ozone).

关键词： HO_(2)uptake kinetics Offine method Impacting factors Mechanism

Deposition of thin TiO_(2)films on fluorophlogopite particle surface by CVD in fluidized bed reactor to prepare silver pearlescent pigments

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第6期89卷 88-98页

作者： Ming Liu Guoqiang shao Pengpeng Lv jun Li Qingshan Zhu State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

Two critical parameters:Glossiness and chromaticity space of pearlescent pigments were evaluated based on crystallinity and grain *** the roughness and the vertical distance evolution along the surface of deposited TiO_(2)film are affected by the *** optimal crystallinity of TiO_(2)was deposited at the temperature of 350℃.The TiCl4 concentration effectively changed the grain ***,the high flow rate of fluidizing gas and optimal gas–solid ratio(<0.11 m^(3)/(kg h))restricted the change of TiCl_(4)concentrations in fluidized bed *** this case,the grain size of the deposited TiO_(2)film was about 55 *** on the grain size,the color of pearlescent pigments was adjusted by controlling the film thickness based on TiO_(2)***,the silver pearlescent pigment with high glossiness was prepared by chemical vapor deposition method in a fluidized bed reactor.

关键词： Fluidized bed chemical vapor deposition TiO_(2)film deposition Pearlescent pigment Free powder restrain Crystal growth

To be or not to be direct:The role of neuromedin U in neuro-eosinophil crosstalk

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science Bulletin 2024年第2期69卷 148-150页

作者： Ruichao Liu Wenhao shao jun Xu Coco Chu SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine Taiyuan 030001China Insttute for Immunogy Department of Basic Medical SciencesSchool of Medicinesinghua UnierstyBejing 100084China Tsinghua-Peking Center for Life Sciences Tsinghua UniversityBeijing 100084China Shanxi Medical University Taiyuan 030012China Department of Surgery First Hospital of Shanxi Medical UniversityShanxi Provincial Key Laboratory for Digestive Diseases and Organ TransplantationTaiyuan 030001China Beijing Key Laboratory for Immunological Research on Chronic Diseases Tsinghua UniversityBejing 100084China

With the development of new experimental techniques(e.g.,single-cell RNA sequencing(scRNA-seq),light sheet microscopy,and clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9),emerging studies have begun to uncover the interactions between the nervous system and the immune system,both in health and *** example,in mucosal tissues such as the lung and the intestine,neurotransmitters including acetylcholine[1]and adrenaline[2]can directly regulate the immune cell functions thus affect the results of allergy,asthma,and anti-pathogen host defense[3].

关键词： intestine lung asthma

Heat distribution model under hydrogen-rich low-carbon conditions in blast furnace

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 2024年第3期31卷 584-594页

作者： Gang Wang jun Xu Kun He Zhong-ping Zou Hao bai School of Metallurgy and Ecological Engineering University of Science and Technology BeijingBeijing 100083China CISDI Low-Carbon Blast Furnace Research Office MCC Low-Carbon Technology Research InstituteChongqing 401122China

Low carbon development of blast furnaces is one of the key technological directions in the current development of *** to the differences in the physical and chemical properties of hydrogen and carbon,hydrogen-rich media entering a blast furnace will change the heat distribution,thus affecting the stability of ***,a heat distribution model was proposed to study the temperature distribution in a blast furnace,simultaneously considering gas-solid heat exchange,slag and iron melting,and chemical *** model was used to analyze the temperature distribution of a 2300 m^(3) blast furnace and was verified via comparison with actual production ***,the effects of the injection rate of hydrogen-rich media,H2 concentration,and oxygen enrichment rate of the blast on the temperature distribution were *** indicated that the increase in the injection rate of the hydrogen-rich media decreased the amount of direct reduction and led to an increase in the furnace ***,an increase in the oxygen enrichment rate led to a decrease in the furnace temperature,but could reduce the solid fuel ratio,while the change in H2 concentration had less effect on the temperature *** combination of hydrogen-rich media injection and the increase in the oxygen enrichment rate would help to adjust the temperature distribution to the same level as the conventional blast furnace conditions.

关键词： Heat distribution Blast furnace Low-carbon condition Hydrogen enrichment Calculation model