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Higher pressure differentiation of arc magmas under thicker crust

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National Science Review 2023年第3期10卷 100-101页

作者： yi-gang Xu State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)

The formation of continental crust is pivotal to understanding the evolution of the earth and its *** average intermediate or’andesitic’bulk composition and characteristic depletion of niobium of the continental crust are strikingly matched by convergent margin magmas [1].This has led to the inference that most continental crust is derived from igneous,arc ***,continental crust has characteristically higher Mg#(>0.5) than most oceanic arc andesites (<0.5).

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Microstructure and properties of YG8 cemented carbide with different pulse currents

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Rare Metals 2020年第5期39卷 597-606页

作者： Liao Wei yi Yang gang Yang School of Mechanical Engineering Sichuan UniversityChengdu 610065China College of Arts and Sciences Guangxi Radio and TV UniversityNanning 530022China

In order to study the effect of pulse current treatment on the mechanical properties,microstructure and cutting performance of YG8 cemented carbide,experiments were carried out by using self-made pulse current treatment device to treat cemented carbide samples with different current densities(J=5,10 and 15 A·mm^-2)After the treatment of pulse current,when the current density increased from 5 to 15 A·mm-2,the hardness of the sample was improved to HV 1605,HV 1629 and HV 1653from HV 1574;the transverse rupture strengths of the sample were 2136,2289 and 2364 MPa,which were all higher than that of the untreated sample(2062 MPa)increasing by 3.6%,11.0%and 14.6%,respectively;the corresponding cutting performance was increased by10.1%,13.9%and 19.4%,compared to that of the untreated *** tool’s life was also *** the treatmen of pulse current,pulse current provided the driving force for dislocation motion,making it more likely for the dislocation to multiply and slip,the dislocation density was increased,and the mechanical properties were significantly improved.

关键词： Pulse current YG8 cemented carbide Microstructure Mechanical properties Cutting performance

Bioaugmentation of two-stage aerobic sequencing batch reactor with mixed strains for high nitrate nitrogen wastewater treatment

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Chinese Journal of Chemical Engineering 2020年第12期28卷 3103-3109页

作者： Mengmeng Wang gang cao Naixian Feng Yongzhang Pan College of Environment Jinan UniversityGuangzhou 511443China Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials College of Life Science and TechnologyJinan UniversityGuangzhou 510632China

Mixed strains Delftia ***01 and Acidovorax ***02,with capability of heterotrophic nitrification-aerobic denitrification,were introduced into a two-stage aerobic sequencing batch reactor to enhance NO3^--N *** optimal C/N of 8,efficient NO3^--N removal was achieved at initial NO3^--N concentration of 2000 mg·L−***,the massive accumulation of NO2^--N was avoided during the long *** to the one-stage aerobic sequencing batch reactor,the removal efficiency of NO3^--N and TN in the two-stage aerobic sequencing batch reactor was increased by 36.5% and 42.7%,which respectively was 93.8% and 88.4%.Microbial community study showed that the mixed strains have the stronger viability and can synergistically denitrify with the indigenous microorganisms in system,such as Azoarcus,Uncultured Saprospiraceae,Thauera,Paracocccus,which could be major contributors for aerobic *** proposed technology was shown to achieve high-efficiency treatment of high NO3^--N wastewater through aerobic denitrification.

关键词： Waste water Biological engineering Bioreactors Aerobic denitrification Bioaugmentation Microbial community

Numerical simulation of ice accretion in supercooled large droplet conditions

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Science China(Technological Sciences) 2019年第7期62卷 1191-1201页

作者： cao yi Hua XIN Miao School of Aeronautic Science and Engineering Beihang University

The simulated methods for ice accretion on two-dimensional airfoil surface are established completely under the Eulerian framework in supercooled large droplet(SLD) conditions. The two-dimensional code to solve the partial differential equations(PDEs) of droplet phase is derived to simulate the impingement characteristic of SLD. Also, several semi-empirical models which explain the droplet-wall interaction are compared and discussed to show respective features when simulating the splashing phenomenon. In particular, a new boundary condition for wall called penetrable wall for splashing droplet(PWSD) is proposed to deal with the impingement of SLD on solid surface, which efficiently improves the accuracy of simulation. Then the improved impingement characteristic of SLD is input into the extended mass and heat transfer model to simulate the ice growth on airfoil surface. The multistep advanced method is carried out to better match the physical phenomenon of ice growth. At last, the simulated results of critical parameters: local droplet collection efficiency and the height of ice growth are compared with the experimental data which verify the applicability of proposed models.

关键词： numerical simulation supercooled large droplet ice accretion penetrable wall for splashing droplet

Resilience-incorporated seismic risk assessment of precast concrete frames with“dry”connections

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 403-425页

作者： Wu Chenhao Tang Yuchuan cao Xuyang Wu gang Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education Nanjing 211102China Department of Civil and Environmental Engineering University of CaliforniaLos AngelesCA 90095USA School of Civil Engineering Southeast UniversityNanjing 211102China College of Civil and Transportation Engineering Hohai UniversityNanjing 210024China

A resilience-incorporated risk assessment framework is proposed and demonstrated in this study to manifest the advantageous seismic resilience of precast concrete frame(PCF)structures with“dry”connections in terms of their low damage and rapid *** framework integrates various uncertainties in the seismic hazard,fragility,capacity,demand,loss functions,and post-earthquake *** this study,the PCF structures are distinguished from ordinary reinforced concrete frame(RCF)structures by characterizing multiple limit states for the PCF based on its unique damage ***,probabilistic story-wise pushover analyses are performed to yield story-wise capacities for the predefined limit *** the seismic resilience analysis,a step-wise recovery model is proposed to idealize the functionality recovery process,with separate considerations of the repair and non-repair *** recovery model leverages the economic loss and downtime to delineate the stochastic post-earthquake recovery curves for the resilience loss *** such,contingencies in the probabilistic post-earthquake repairs are incorporated and the empirical judgments on the recovery parameters are largely *** proposed framework is demonstrated through a comparative study between two“dry”connected PCFs and one RCF designed as alternative structural systems for a prototype *** results from the risk quantification indicate that the PCFs show reduced loss hazards and lower expected losses relative to the ***,the PCF equipped with energy dissipation devices at the“dry”connections largely reduces the expected economic loss,downtime,and resilience loss by 29%,56%,and 60%,respectively,compared to the RCF.

关键词： precast concrete frame non-emulative precast system seismic resilience seismic risk functional recovery

Three-dimensional finite element analysis with different internal fixation methods through the anterior approach

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World Journal of Clinical Cases 2021年第8期9卷 1814-1826页

作者： Xian-Jin Xie Sheng-Lu cao Kai Tong Zi-yi Zhong gang Wang Department of Orthopaedic Surgery Nanfang HospitalSouthern Medical UniversityGuangzhou 510515Guangdong ProvinceChina Department of Orthopaedic Surgery Zhongnan HospitalWuhan UniversityWuhan 430000Hubei ProvinceChina

BACKGROUND With the modernization of society and transportation in the last decades in China,the incidence of high-energy trauma increased sharply in China,including that of acetabular *** To establish different finite element models for acetabular posterior column fractures involving the quadrilateral area of the *** The three-dimensional models of the normal and fractured pelvis and the five internal fixations were established using the computed tomography data of the pelvis of a living *** the vertebral body model was inserted in the way of origin matching and all cancellous bones were copied using the duplicated cancellous bone model as the subtractive entity,the Boolean operation was performed on the pelvis model to obtain the model of the complete pelvis cortical and cancellous *** In the standing position,the maximum stress was 46.21 *** the sitting position,the sacrum bore the simulated gravity load at the upper *** comparing the five fixations,there were no significant differences in the stress mean values among groups(sitting:P=0.9794;standing:P=0.9741).In terms of displacement,the average displacement of the internal iliac plate group was smaller than that of the spring plate group(P=0.002),and no differences were observed between the other pairs of groups(all P>0.05).In the standing position,there were no significant differences in the mean value of displacement among the groups(P=0.2985).It can be seen from the stress nephogram of the internal fixations in different positions that the stress of the internal fixation was mainly concentrated in the fracture *** There were no significant differences among the fixations for acetabular posterior column fractures involving the quadrilateral area of the acetabulum.

关键词： Acetabulum Hip fractures Analysis Finite element Fracture fixation Orthopedic fixation devices

NORMALIZED DIFFERENCE SNOW INDEX SIMULATION FOR SNOW-COVER MAPPING IN FOREST BY GEOSAIL MODEL

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Chinese Geographical Science 2006年第2期16卷 171-175页

作者： cao Yun-gang LIU Chuang Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 P.R. China Graduate School of Chincse Academy of Sciences Beijing 100049 P. R. China

The snow-cover mapping in forest area is always one of the difficult points for optical satellite remote sensing. To investigate reflectance variability and to improve the mapping of snow in forest area, GeoSail model was used to simulate the reflectance of a snow-covered forest. Using this model, the effects of varying canopy density, solar illumination and view geometry on the performance of the MODIS (Moderate-resolution Imaging Spectroradiometer) snow-cover mapping algorithm were investigated. The relationship between NDSI (Normalized Difference Snow Index), NDVI (Normalized Difference Vegetation Index) and snow fraction was discussed in detail. Results indicated that the weak performance would be achieved if fixed criteria were used for different regions especially in the complicated land cover components. Finally, some suggestions to MODIS SNOWMAP algorithm were put forward to improve snow mapping precision in forest area based on the simulation, for example, new criteria should be used in coniferous forest, that is, NDSI greater than 0.3 and NDVI greater than zero. Otherwise, a threshold on view zenith angle may be used in the criteria such as 45°.

关键词： snow cover mapping reflectance model MODIS

NUMERICAL SIMULATION OF FISH SWIMMING WITH RIGID PECTORAL FINS

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Journal of Hydrodynamics 2012年第2期24卷 263-272页

作者： XU yi-gang WAN De-cheng State Key Laboratory of Ocean Engineering School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

The numerical simulation of the self-propelled motion of a fish with a pair of rigid pectoral fins is presented.A Navier-Stokes equation solver incorporating with the multi-block and overset grid method is developed to deal with the multi-body and moving body *** lift-based swimming mode is selected for the fin *** the lift-based swimming mode,the fin can generate great thrust and at the same time have no generation of lift *** can be found when a pair of rigid pectoral fins generates the hydrodynamic moment,it may also generate a lateral force opposite to the centripetal direction,which has adverse effect on the turn motion of the ***,the periodic vortex structure generation and shedding,and their effects on the generation of hydrodynamic force are also demonstrated in this article.

关键词： pectoral fins lift-based swimming mode self-propelled motion overset grid method

Poroelastic behaviors of the osteon: A comparison of two theoretical osteon models

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Acta Mechanica Sinica 2013年第4期29卷 612-621页

作者： Xiao-gang Wu Wei-yi Chen College of Mechanics Taiyuan University of Technology

In the paper, two theoretical poroelastic osteon models are presented to compare their poroelastic behaviors, one is the hollow osteon model （Haversian fluid is neglected） and the other is the osteon model with Haversian fluid con- sidered. They both have the same two types of imperme- able exterior boundary conditions, one is elastic restraint and the other is displacement constrained, which can be used for analyzing other experiments performed on similarly shaped poroelastic specimens. The obtained analytical pressure and velocity solutions demonstrate the effects of the loading fac- tors and the material parameters, which may have a signifi- cant stimulus to the mechanotransduction of bone remodel- ing signals. Model comparisons indicate：（1） The Haversian fluid can enhance the whole osteonal fluid pressure and ve- locity fields. （2） In the hollow model, the key loading fac- tor governing the poroelastic behavior of the osteon is strain rate, while in the model with Haversian fluid considered, the strain rate governs only the velocity. （3） The pressure ampli- tude is proportional to the loading frequency in the hollow model, while in the model with Haversian fluid considered, the loading frequency has little effect on the pressure ampli- tude.

关键词： Osteon ~ Poroelasticity ~ Haversian fluid - Porepressure ~ Annular cylinder