检索结果-南通市图书馆

Modeling co-seismic thermal infrared brightness anomalies in petroliferous basins surrounding the North and East of the Qinghai–Tibet Plateau

引用

Earth and Planetary Physics 2020年第3期4卷 296-307页

作者： Xin zhang lifeng zhang Key Laboratory of Earthquake Monitoring and Disaster Reduction Technology Guangdong Earthquake AgencyGuangzhou 510070China Qinghai Earthquake Agency Xining 810001China

Co-seismic gas leakage usually occurs on the edge of seismic faults in petroliferous basins,and it may have an impact on the local environment,such as the greenhouse effect,which can cause thermal infrared brightness *** wavelet transform and power spectrum estimation methods,we processed brightness temperature data from the Chinese geostationary meteorological satellite FY-C/*** report similarities between the co-seismic thermal infrared brightness(CTIB)anomalies before,during and after earthquakes that occurred at the edges of the Sichuan,Tarim,Qaidam,and Junggar basins surrounding the North and East of the Qinghai–Tibet Plateau in western ***,in each petroliferous basin,the area of a single CTIB anomaly accounted for 50%to 100%of the basin area,and the spatial distribution similarities in the CTIB anomalies existed before,during and after these *** better interpret the similarities,we developed a basin warming effect model based on geological structures and *** model suggests that in a petroliferous basin with a subsurface gas reservoir,gas leakage could strengthen with the increasing stress before,during,and even after an *** accumulation of these gases,such as the greenhouse gases CH4 and CO2,results in the CTIB *** addition,we conclude that the CTIB anomalies are strengthened by the high mountains(altitude^5000 m)around the basins and the basins’independent climatic *** work provides a new perspective from which to understand the CTIB anomalies in petroliferous basins surrounding the North and East of the Qinghai–Tibet Plateau.

关键词： co-seismic thermal infrared brightness(CTIB) relative power spectrum(RPS) gas leakage basin warming effect

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Numerical simulation on inclusion transport in continuous casting mold

引用

Journal of University of Science and Technology Beijing 2006年第4期13卷 293-300页

作者： lifeng zhang Brian G Thomas Department of Materials Science ＆ Engineering Norwegian University of Science ＆ Technology （NTNU） Alfred Getz vei 2 N-7491 Trondheim Norway University of Illinois at Urbana-Champaign 1206 W. Green St. Urbana IL 61801 USA

Turbulent flow, the transpor＇t of inclusions and bubbles, and inclusion removal by fluid flow, transport and by bubble flotation in the strand of the continuous slab caster are investigated using computational models, and validated through comparison with plant measurements of inclusions. Steady 3-D flow of steel in the liquid pool in the mold and upper strand is simulated with a finitedifference computational model using the standard k-εturbulence rondel. Trajectories of inclusions and bubhles tire calculated by integrating each local velocity, considering its drag and buoyancy forces, A ＂random walk＂ model is used to incorporate the effect of turbulent fluctuations on the particle motion. The attachment probability of inclusions on a bubble surface is investigated based on fundamental fluid flow simulations, incorporating the turbulent inclusion trajectory and sliding time of each individual inclusion along the bubble surface as a function of particle and bubble size. The chunge in inclusion distribution due to removal by bubble transport in the mold is calculated based on the computed attachment probability of inclusions on each bubble and the computed path length of the bubbles. The results indicate that 6%-10% inclusions are removed by fluid flow transport. 10% by bubble flotation, and 4% by entrapment to the submerged entry nozzle （SEN） walls. Smaller bubbles and larger inclusions have larger attachment probabilities. Smaller bubbles are more efficient for inclusion removal by bubble flotation, so Inng as they are not entrapped in the solidifying shell A larger gas flow rate favors inclusion removal by bubble flotation. The optimum bubble size should be 2-4mm.

关键词： inclusion removal fluid flow transport bubble flotation continuous casting mold attachment probability

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Handling non-linearity in radar data assimilation using the non-linear least squares enhanced POD-4DVar

引用

Science China Earth Sciences 2017年第3期60卷 478-490页

作者： zhang Bin TIAN XiangJun zhang lifeng SUN JianHua International Center for Climate and Environment Sciences(ICCES) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Meteorology and Oceanography PLA University of Science and TechnologyNanjing 211101China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China Ley Laboratory of Cloud-Precipitation Physics and Severe Storms(LACS) Institute of Atmospheric PhysicsChinese Academy of Sciences Beijing 100029China

The Proper Orthogonal Decomposition(POD)-based ensemble four-dimensional variational(4DVar) assimilation method(POD4DEnVar) was proposed to combine the strengths of EnKF(i.e.,the ensemble Kalman filter) and 4DVar assimilation ***,a POD4DEnVar-based radar data assimilation scheme(PRAS) was built and its effectiveness was ***4 DEnVar is based on the assumption of a linear relationship between the model perturbations(MPs)and the observation perturbations(OPs);however,this assumption is likely to be destroyed by the highly non-linear forecast model or observation *** address this issue,using the Gauss-Newton iterative method,the nonlinear least squares enhanced POD4 DEnVar algorithm(referred to as NLS-4DVar) was ***,the PRAS was upgraded to form the NLS-4DVar-based radar data assimilation scheme(NRAS).To evaluate the performance of NRAS against PRAS,observing system simulation experiments(OSSEs) were conducted to assimilate reflectivity and radial velocity individually,with one,two,and three *** results demonstrated that the NRAS outperformed PRAS in improving the initial condition and the forecasting of model variables and *** NRAS,with a smaller number of iterations,can yield a convergent *** contrast to the situation when assimilating radial velocity,the advantages of NRAS over PRAS were more obvious when assimilating reflectivity.

关键词： Data assimilation Non-linearity Gauss-Newton NRAS PRAS Radar reflectivity Radial velocity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

In situ observation of the dissolution kinetics of Al_(2)O_(3) particles in CaO–Al_(2)O_(3)–SiO_(2) slags using laser confocal scanning microscopy

引用

International Journal of Minerals,Metallurgy and Materials 2023年第2期30卷 345-353页

作者： Changyu Ren Caide Huang lifeng zhang Ying Ren School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China Shougang Jingtang United Iron and Steel Co. Ltd.Tangshan 063200China School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

The dissolution kinetics of Al_(2)O_(3) in CaO-Al_(2)O_(3) SiOslags was studied using a high-temperature confocal scanning laser microscope at 1773 to 1873 *** results show that the controlling step during the Al_(2)O_(3) dissolution was the diffusionin molten *** was found that the dissolution curves of Al_(2)O_(3) particles were hardly agreed with the traditional boundary layer diffusion model with the increase of the CaO/Al_(2)O_(3) ratio of slag.A modified diffusion equation considering slag viscosity was developed to study the dissolution mechanism of Al_(2)O_(3) in *** coefficients of Al_(2)O_(3) in slag were calculated as 2.8×10to 4.1×10m~2/s at the temperature of 1773-1873 *** dissolution rate of Al_(2)O_(3) increased with higher temperature,CaO/Al_(2)O_(3),and particle size.A new model was shown to be v_(Al_(2)O_(3))=0.16×r_(0)^(1.58)×x^(3.52)×(T-T_(mp))^(1.11)to predict the dissolution rate and the total dissolution time of Al_(2)O_(3) inclusions with various sizes,where vAl_(2)O_(3) is the dissolution rate of Al_(2)O_(3) in volume,μm^(3)/s;x is the value of CaO/Al_(2)O_(3) mass ratio;R_(0) is the initial radius of Al_(2)O_(3),μm;T is the temperature,K;T_(mp) is the melting point of slag,K.

关键词： inclusion dissolution kinetics confocal scanning laser microscope refining slag

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Influence of substituting B_(2)O_(3) with Li_(2)O on the viscosity,structure and crystalline phase of low-reactivity mold flux

引用

International Journal of Minerals,Metallurgy and Materials 2023年第7期30卷 1320-1328页

作者： Rongzhen Mo Xubin zhang Ying Ren Junjie Hu lifeng zhang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Lecture at College of Materials Science and Engineering Chongqing UniversityChongqing 400030China School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

The low-reactivity mold flux with low SiO_(2)content is considered suitable for the continuous casting of high-aluminum steel since it can significantly reduce the reaction between Al in steel and SiO_(2)in mold ***,the traditional low-reactivity mold flux still presents some problems such as high viscosity and strong crystallization *** this study,the co-addition of Li_(2)O and B_(2)O_(3)in CaO–Al_(2)O_(3)–10wt%Si O_(2)based low-reactivity mold flux was proposed to improve properties of mold flux for high-aluminum steel,and the effect of Li_(2)O replacing B_(2)O_(3)on properties of mold flux was *** viscosity of the mold flux with 2wt%Li_(2)O and 6wt%B_(2)O_(3)reached a minimum value of 0.07 Pa·*** break temperature and melting point showed a similar trend with the ***,the melt structure and precipitation of the crystalline phase were studied using Raman and X-ray diffraction spectra to better understand the evolution of *** demonstrated that with increasing Li_(2)O content in the mold flux from 0 to 6 wt%,the degree of polymerization of aluminate and the aluminosilicate network structure increased because of increasing Li+released by Li_(2)O,indicating the added Li_(2)O was preferentially associated with Al^(3+)as a charge *** precipitation of LiAlO_(2)crystalline phase gradually increased with the replacement of B_(2)O_(3)by Li_(2)***,Li_(2)O content should be controlled below 2wt%to avoid LiAlO_(2)precipitation,which was harmful to the continuous casting of highaluminum steels.

关键词： low-reactivity mold flux viscosity structure crystalline phase

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mathematical simulation of hot metal desulfurization during KR process coupled with an unreacted core model

引用

International Journal of Minerals,Metallurgy and Materials 2022年第4期29卷 758-766页

作者： Yanyu Zhao Wei Chen Shusen Cheng lifeng zhang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

A three-dimensional mathematical model was established to predict the multiphase flow,motion and dispersion of desulfurizer particles,and desulfurization of hot metal during the Kanbara reactor(KR)*** turbulent kinetic energy-turbulent dissipation rate(k-ε)turbulence model,volume-of-fluid multiphase model,discrete-phase model,and unreacted core model for the reaction between the hot metal and particles were *** measured sulfur content of the hot metal with time during the actual KR process was employed to validate the current mathematical *** distance from the lowest point of the liquid level to the bottom of the ladle decreased from 3170 to2191 mm when the rotation speed increased from 30 to 110 r/min,which had a great effect on the dispersion of desulfurizer *** critical rotation speed for the vortex to reach the upper edge of the stirring impeller was 70 r/min when the immersion depth was 1500 *** desulfurization rate increased with the increase in the impeller rotation speed,whereas the influence of the immersion depth was relatively *** for different rotation parameters on the desulfurization rate constant and turbulent energy dissipation rate were proposed to evaluate the variation in sulfur content over time.

关键词： desulfurization unreacted core model desulfurizer dispersion KR process fluid flow

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Precise control of Pt encapsulation in zeolite-based catalysts for a stable low-temperature CO oxidation reaction

引用

Science China Chemistry 2022年第10期65卷 2015-2022页

作者： Yatian Liu lifeng zhang Zejian Dong Langli Luo Institute of Molecular Plus Tianjin UniversityTianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

Metal–zeolite catalysts are vital in chemical and fuel production for their great stability,stereo-selectivity,and atom *** metal species keep shrinking their sizes to the subnanometer region,their spatial distribution in the zeolite framework/channels could have a great impact on their catalytic ***,we precisely control the Pt species loaded on a silicalite-1 zeolite and characterize their structural status to the catalytic performance for CO *** find that Pt species exits as few-atom clusters encapsulated in the channels and destructively embedded Pt nanoparticles in the framework,besides the conventional surface-supported *** utilizing effective Pt sites and limiting their sizes in the zeolite,we can maximize the catalytic CO oxidation performance of 1 at.% Pt-loaded zeolite catalysts to achieve a T100 as low as 90 ℃ and a stable reaction above 216 h.

关键词： zeolites encapsulation CO oxidation Pt atomic scale

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ethanol steam reforming over Ni-Cu/Al_2O_3-M_yO_z (M = Si, La, Mg,and Zn) catalysts

引用

Journal of Natural Gas Chemistry 2009年第1期18卷 55-65页

作者： lifeng zhang Jie Liu Wei Li Cuili Guo Jinli zhang School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

Ni-based catalysts doped with copper additives were studied on their role in ethanol steam reforming reaction. The effects of Cu content, support species involving Al2O3-SIO2, Al2O3-MgO, Al2O3-ZnO, and Al2O3-La2O3, on the catalytic performance were studied. Characterizations by TPR, XRD, NH3-TPD, XPS, and TGA indicated that catalysts 30Ni5Cu/Al2O3-MgO and 30Ni5Cu/Al2O3-ZnO have much higher H2 selectivity than 30Ni5Cu/Al2O3-SiO2, as well as good coke resistance. H2 selectivity for 30Ni5Cu/Al2O3-MgO catalyst was 73.3% at 450 ℃ and increased to 94.0% at 600℃, whereas for 30Ni5Cu/Al2O3-ZnO catalyst, the H2 selectivity was 63.6% at 450 ℃ and 95.2% at 600℃. TheseAl2O3-MgO and Al2O3-ZnO supported Ni-Cu bimetallic catalysts may have important applications in the production of hydrogen by ethanol steam reforming reactions.

关键词： ethanol steam reforming nickel-copper-based catalyst Al2O3-SO2 support Al2O3-MgO support Al2O3-ZnO support Al2O3-La2O3 support

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Spatial Agglomeration of Exhibition Enterprises on a Regional Scale in China

引用

Chinese Geographical Science 2017年第3期27卷 497-506页

作者： FANG Zhongquan zhang Ying WANG zhangjun zhang lifeng College of Tourism Beijing Union University School of Management Jinan University

During the past two decades, the exhibition industry in China has been developing rapidly and has become an important part of the modern service industry, particularly the agglomeration characteristics of exhibition enterprises highlighted on the regional scale. Although the development of theoretical research on the western exhibition industry has taken place over time, the spatial perspective has not been at the centre of attention so far. This paper aims to fill this gap and report on the agglomeration characteristics of exhibition enterprises and their influential factors. Based on data about exhibition enterprises in the Pearl River Delta(PRD) during 1991–2013, using the Ripley K function analysis and kernel density estimation, this research identifies that: 1) the exhibition enterprise on the regional scale is significantly characterized by spatial agglomeration, and the agglomeration density and scale are continuously increasing; 2) the spatial pattern of agglomeration has developed from a single-center to multi-center form. Meanwhile, this paper profiles the factors influencing the spatial agglomeration of exhibition enterprises by selecting the panel data of nine cities in the PRD in 1999, 2002, 2006 and 2013. The results show that market capacity, urban informatization level and exhibition venues significantly influence the location choice of exhibition enterprises. Among them, the market capacity is a variable that exerts a far greater impact than other factors do.

关键词： exhibition enterprises spatial agglomeration Ripley K function analysis regional scale Pearl River Delta

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Interdecadal change of winter SST variability in the Kuroshio Extension region and its linkage with Aleutian atmospheric low pressure system

引用

Acta Oceanologica Sinica 2016年第5期35卷 24-37页

作者： YU Peilong zhang lifeng zhang Yongchui DENG Bing College of Meteorology and Oceanography PLA University of Science and Technology Nanjing 211101 China Beijing Institute of Applied Meteorology Beijing 100029 China

By utilizing multiple datasets from various sources available for the last 100 years, the existence for the interdecadal change of the winter sea surface temperature（SST） variability in the Kuroshio Extension（KE） region is investigated. And its linkage with the Aleutian Low（AL） activity changes is also discussed. The results find that the KE SST variability exhibits the significant ~6 a and ~10 a oscillations with obvious interdecadal change. The ~6 a oscillation is mainly detected during 1930–1950, which is largely impacted by the anomalous surface heat flux forcing and Ekman heat transport associated with the AL intensity variation. The ~10 a oscillation is most evident after the 1980s, which is predominantly triggered by the AL north-south shift through the bridge of oceanic Rossby waves.

关键词： sea surface temperature(SST) variability interdecadal change Kuroshio Extension Aleutain Low

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：