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Experimental and kinetic study on laminar flame speeds of ammonia/syngas/air at a high temperature and elevated pressure

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Frontiers in Energy 2022年第2期16卷 263-276页

作者： Geyuan YIN Chaojun WANG Meng ZHOU Yajie ZHOU Erjiang HU Zuohua HUANG State key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China key Laboratory for Thermal Science and Power Engineering of the ministry of education Department of Thermal EngineeringTsinghua UniversityBeijing 100084China

The laminar flame speeds of ammonia mixed with syngas at a high pressure, temperature, and different syngas ratios were measured. The data obtained were fitted at different pressures, temperatures, syngas ratios, and equivalence ratios. Four kinetic models (the Glarborg model, Shrestha model, Mei model, and Han model) were compared and validated with experimental data. Pathway, sensitivity and radical pool analysis are conducted to find out the deep kinetic insight on ammonia oxidation and NO formation. The pathway analysis shows that H abstraction reactions and NHi combination reactions play important roles in ammonia oxidation. NO formation is closely related to H, OH, the O radical produced, and formation reactions. NO is mainly formed from reaction, HNO+ H= NO+ H2. Furthermore, both ammonia oxidation and NO formation are sensitive to small radical reactions and ammonia related reactions.

关键词： ammonia mixed with syngas laminar flame speed kinetic model sensitivity analysis pathway analysis

Development and prospects of garnet ceramic scintillators:A review

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Journal of Advanced Ceramics 2022年第12期11卷 1825-1848页

作者： Danyang ZHU Martin NIKL Weerapong CHEWPRADITKUL Jiang LI key Laboratory of Transparent Opto-functional Inorganic Materials Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 201899China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Institute of Physics The Czech Academy of SciencesPrague 16200Czech Republic Department of Physics King Mongkut’s University of Technology ThonburiBangkok 10140Thailand

Garnet ceramic scintillators are a class of inorganic scintillation materials with excellent overall *** flexibility of cation substitution in different lattice positions leads to tunable and versatile properties and a wide range of *** paper starts with an overview of the development history of the inorganic scintillation materials,followed by a description of major preparation methods and characterization of garnet scintillation *** progress obtained in recent years consisting in applying the band-gap and defect engineering strategies to the garnet scintillation ceramics is ***,the respective problems in the preparation and performance of multicomponent garnet single crystals and ceramics and the effective solutions are *** garnet scintillation ceramics with the highest application potential are summarized,and the future development directions are proposed.

关键词： garnet ceramics inorganic scintillators single crystals scintillation performance

AN EQUIVALENT CONTINUUM METHOD OF LATTICE STRUCTURES

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Acta Mechanica Solida Sinica 2006年第2期19卷 103-113页

作者： Fan Hualin Yang Wei Department of Engineering Mechanics Tsinghua University Beijing 100084 China

An equivalent continuum method is developed to analyze the effective stiffness of three-dimensional stretching dominated lattice materials. The strength and three-dimensional plastic yield surfaces are calculated for the equivalent continuum. A yielding model is formulated and compared with the results of other models. The bedding-in effect is considered to include the compliance of the lattice joints. The predicted stiffness and strength are in good agreement with the experimental data, validating the present model in the prediction of the mechanical properties of stretching dominated lattice structures.

关键词： stretching dominated lattice materials equivalent continuum method effective stiffness yield surface bedding-in effect

Application of Stereology on Neodymium-Doped Yttrium Aluminum Garnet (Nd∶YAG) Transparent Ceramics

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Journal of Rare Earths 2006年第5期24卷 538-542页

作者：张华山荆敏苏春辉张洪波候朝霞邵晶宋琼 School of Materials and Chemical Engineering Changchun University of Science and Technology chinese Special Vehicle Institute

Nd ： YAG precursor powders were synthesized by homogeneous precipitation, and Nd ： YAG transparent ceramics were prepared by vacuum sintering at 1700 ℃ for 5 h. The ceramic materials were characterized by light transmittance and field emission gun-environment scanning microscope. Using statistics and stereology theory, study was carried out on the quantitative relationships between light transmittance and stereological parameters in three-dimensional Euclidean space. It is found that the transmittance of Nd：YAG with 1 mm in thickness is about 45% and 58% in visible and near-infrared wavelength, respectively. The transmittance linearly increases with increasing equivalent sphere diameter and reaches the theoretical value of single crystal when the equivalent sphere diameter is 20μm. The transmittance decreases with the increasing of mean specific area per unit volume of grain and discrete grains, and the transmittance decreases with increasing mean free distance of grains in Nd：YAG ceramics.

关键词： neodymium doped yttrium aluminum garnet transparent ceramics stereology microstructure rare earths

In-situ observations of damage-fracture evolution in surrounding rock upon unloading in 2400-m-deep tunnels

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International Journal of Mining Science and Technology 2023年第4期33卷 437-446页

作者： Haosen Guo Qiancheng Sun Guangliang Feng Shaojun Li Yaxun Xiao Jiangxi key Laboratory of Disaster Prevention-mitigation and Emergency Management Nanchang 330013China key Laboratory of Geological Hazards on Three Gorges Reservoir Area Ministry of EducationYichang 443002China College of Civil Engineering and Architecture China Three Gorges UniversityYichang 443002China State key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China

The damage-fracture evolution of deep rock mass has obvious particularity,which is revealed in 2400-mdeep tunnels by field *** evolution of the excavation damaged zone depth is consistent with that of the fractured zone *** ratio of the excavation damaged zone depth to the excavation fractured zone depth is greater than 2.0 in a rock mass with both high strength and good integrity,but less than1.5 in a rock mass with lower strength or poor *** disintegration in a rock mass with high strength and fair integrity is more likely to occur when it contains more than two groups of primary fractures in damaged *** develop outward in zonal disintegration but are totally different from the single-zone fracture,in which the fractures develop inward,and it is the starting position of the fractured zone when the excavation surface of the middle pilot is 7–9 m close to the pre-set borehole and it stops after the excavation surface of the baseplate is 11–14 m *** most intense evolution occurs around 2–4 m from the pre-set borehole in the sidewall expansion *** research results provide a reference for the monitoring scheme and support design of CJPL-Ⅲin its future construction.

关键词： Deep tunnel Fractured zone Damaged zone In-situ observation Unloading of rock mass

Compositional regulation of multi-component GYGAG:Ce scintillation ceramics:Self-sintering-aid effect and afterglow suppression

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Journal of Advanced Ceramics 2023年第10期12卷 1919-1929页

作者： Danyang Zhu Lexiang Wu Alena Beitlerova Romana Kucerkova Weerapong Chewpraditkul Martin Nikl Jiang Li Transparent Ceramics Research Center Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 201899China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Institute of Physics of the Czech Academy of Sciences Prague 16200Czech Republic King Mongkut’s University of Technology Thonburi Bangkok 10140Thailand

(Gd,Y,Ce)_(3)(Y_(x)Ga_(1−x))_(2)GaAl_(2)O_(12)(GYGAG:Ce)scintillation ceramics with different Y excess,where x=0.005−0.08,were fabricated by the solid-state reaction *** effects of stoichiometry on the phase composition,optical quality,and microstructure of GYGAG:Ce ceramics were ***:Ce ceramics have a pure garnet phase and obtain good in-line transmittance when x<0.04,while more Y excess leads to the creation of the secondary *** change of x value influences the sintering behavior of the GYGAG:Ce ceramics:The excess of Y works as the self-sintering aid and significantly reduces the sintering temperature of *** x=0.01–0.04,the X-ray excited luminescence(XEL)spectra and light yields of GYGAG:Ce ceramics are *** fast scintillation decay time and afterglow intensity of GYGAG:Ce ceramics show a slight decrease with increasing x ***,additional 50–500 ppm MgO and 100–500 ppm CaO were introduced to the GYGAG:Ce ceramic with x=0.04,and both were found to significantly increase the fast scintillation component and reduce the afterglow intensity by two orders of magnitude to 0.01%after X-ray cut-off.

关键词： GYGAG:Ce ceramics multi-component garnet compositional regulation afterglow

The energy release rate for hygrothermal coupling elastic materials

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Acta Mechanica Sinica 2006年第1期22卷 28-33页

作者： Fan Yang Jun Wang Dapeng Chen Institute of Computational Engineering and Science Southwest Jiaotong UniversityChengdu 610031 China Department of Material Science Fudan UniversityShanjzhai 200433. China

In the fracture problems of hydrophilic elastic materials under coupling effects of heat conduction, moisture diffusion and mechanical deformation, the conventional J-integral is no longer path independent. The value of J is unequal to the energy release rate in hygrothermal coupling cases. In the present paper, we derived a general form of the energy release rate for hygrothermal fracture problems of the hydrophilic elastic materials on the basis of energy balance equation in cracked areas. By introducing the constitutive relations and the essential equations of irreversible thermodynamics, a specific expression of the energy release rate was obtained, and the expression can be reformmulated as path independent integrals, which is equivalent to the energy release rate of the fracture body. The path independence of the integrals is then verified numerically.

关键词： Fracture Energy release rate J-integral Hygrothermal coupling problems

Spatiotemporal evolution and driving factors of the rural settlements in the mountain-plain transitional zone

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International Journal of Agricultural and Biological Engineering 2022年第2期15卷 149-155页

作者： Daoliang Sun Buting Hong Ping Ren College of Geography and Resources Science Sichuan Normal UniversityChengdu 610066SichuanChina key Lab of Land Resources Evaluation and Monitoring in Southwest Ministry of EducationSichuan Normal UniversityChengdu 610066SichuanChina Collaborative Innovation Center for Land Resource Development and Protection Sichuan Normal UniversityChengdu 610066SichuanChina Xiangyang Urban Design and Planning Research Institute Xiangyang 441000HubeiChina

Identifying the spatiotemporal evolution characteristics of rural settlements and their driving factors is of great significance to layout optimization of rural settlements,intensive and economical use of rural land,and preparation of land space *** on the mountain-plain transitional zone of Dujiangyan City,China,as the study area,this paper employs methods including landscape pattern index,kernel density estimation,average nearest neighbor index,and Geodetector to quantitatively analyze the spatiotemporal layout evolution characteristics of rural settlements and relevant driving factors in Dujiangyan City over the last *** four main findings are as ***,land use area of rural settlements and the quantity of patches in Dujiangyan exhibited synchronous changes during *** class area(CA)increased from 6161.43 to 7265.43 hm^(2),then declined to 7043.01 hm^(2),and the number of patches(NP)increased from 16543 to 26018,and then declined to ***,the maximum kernel density estimation values in the east and southeast of Dujiangyan City increased remarkably from 48.34 to 74.69 per hm^(2) during ***,the average nearest neighbor index of rural settlements continually decreased in the foregoing 10 years,indicating a higher concentration of rural ***,production and living conditions are the main driving factors of dynamic change in land use in rural settlements,while the impact of socio-economic factors is relatively *** others,the p-value of road accessibility is 0.057,and the impact p-value of land slope is 0.035.

关键词： rural settlement spatiotemporal evolution driving factors geodetector

Integrated Wireless Communication System Using MANET for Remote Pastoral Areas of Tibet

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China Communications 2016年第4期13卷 49-57页

作者： HUANG Cao ZHOU Qing ZHANG Dongchen School of Information Engineering Xizang Minzu University International school Beijing University of Posts and Telecommunications China Mobile Group Design Institute Co. Ltd.

To reduce the network deployment cost and provide voice, message and low rate data services in remote pastoral areas of Tibet effectively, an integrated wireless communication system utilizing MANET(Mobile Ad hoc Network) is proposed. The sparse mobile devices, assisted with the solar-powered multi-functional standing stations mainly on networking maintenance and routing arrangement, self-organize into a MANET. The topology of the standing stations is designed for networking robust and to simplify the routing method and energy strategy. Then in the OMNe T++(Objective Modular Network Test bed in C++) simulation, the energy consumption is analysis while adjusting routing with the different energy status of the standing stations. The result shows that the standing stations should adjust routing as well as control the mobile devices' activity level according to the energy states of the standing stations and their adjacent mobile devices.

关键词： wireless communication system OMNeT++ MANET Tibet