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Effects of Climate Warming on Phenological Characteristics of Urban Forest in Shenyang City,China

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Chinese Geographical Science 2016年第1期26卷 1-9页

作者： he Xingyuan XU sheng XU Wenduo chen Wei HUANG Yanqing WEN Hua State Key Laboratory of Forest and Soil Ecology Institute of Applied EcologyChinese Academy of Sciences Northeast Institute of Geography and Agroecology Chinese Academy of Sciences

Change in plant phenology is one of the most sensitive ecological responses to climate warming. Little information is known about the effects of climate warming on phenology of urban tree species in the northern forest of China. In this study, we investigated the phenological characteristics of the main tree species in the urban forest of shengyang City in China and the correlation between phenology and atmospheric temperature from the discontinuous data during past 42 years over three time periods(from 1962 to 1965, 1977 to 1978, and 2000 to 2005). The results showed that the annual average temperature in Shenyang City showed an increasing trend and increased by 0.96℃ from 1962 to 2005 due to climate warming. The germination phenology of the urban trees was negatively correlated with the temperature in winter and early spring. The leafing phenology was mainly influenced by the temperature in spring before leafing. Influenced by climate warming, the germination, leafing, and flowering phenologies of this urban forest in 2005 were 14, 13, and 10 days earlier than those in 1962, respectively. We inferred that further warming in winter might prolong the growing season of urban trees in the northern forest of China.

关键词： global climate change global warming plant phenology urban forest shengyang City

The influence of radial entrance width of the circular cavity on incident shock wave focusing

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Propulsion and Power Research 2018年第2期7卷 120-128页

作者： Xin chen Chuan Wang sheng Tan Liming he Qiang Zhang Aeronautics and Astronautics Engineering College Air Force Engineering UniversityXi’an 710038China Aerospace Science and Engineering College National University of Defense TechnologyChangsha 410071China

Despite the achievement of shock wave focusing with certain reflectors,the influence of the radial entrance width of a circular cavity on the flow field has yet to be *** this study,we systematically investigated the effects of the shock wave focusing process in a cavity based on the radial entrance *** experimental system was installed to research the evolution of the flow field under conditions with different radial entrance widths of 3.0,11.1,19.5,and 33.0 mm.A schlieren system was used to photograph the structures of the flow field in the cavity,and a data acquisition system was used to record the dynamic pressure histories of different points.A numerical simulation was carried out to investigate greater details of the shock wave focusing process.A third-order strong stability-preserving Runge-Kutta method,third-order weighed essential non-oscillation scheme,and an adaptive mesh refinement algorithm were adopted to simulate the shock wave reflection,diffraction,and focus *** agreement between the experimental and numerical results was *** comparing the evolution process of the flow field under the conditions of four different entrance cavity widths,we found that when the entrance width was 19.5 mm,there was the stronger intensity of the shock wave focusing in the focal region,and the larger pressure value at the apex of the cavity than the other three entrance widths,*** study improves our understanding of shock wave focusing.

关键词： Shock wave focusing Radial entrance widths Cavity Schlieren system Weighed essential nonoscillation

Carbon and Nitrogen Storage in Inner Mongolian Grasslands: Relationships with Climate and Soil Texture

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Pedosphere 2014年第3期24卷 391-398页

作者： he Nian-Peng WANG Ruo-Meng ZHANG Yun-Hai chen Quan-sheng Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences

Understanding the spatial variability of soil carbon （C） storage and its relationship with climate and soil texture is critical for developing regional C models and for predicting the potential impact of climate change on soil C storage. On the basis of soil data from a transect across the Inner Mongolian grasslands, we determined the quantitative relationships of C and nitrogen （N） in bulk soil and particle-size fractions （sand, silt, and clay） with climate and soil texture to evaluate the major factors controlling soil C and N storage and to predict the effect of climate changes on soil C and N storage. The contents of C and N in the bulk soil and the different fractions in the 0 20 and 20 40 cm soil layers were positively correlated with the mean annum precipitation （MAP） and negatively correlated with the mean annual temperature （MAT）. The responses of C storage in the soil and particle-size fractions to MAP and MAT were more sensitive in the 0-20 cm than in the 2（~40 cm soil layer. Although MAP and MAT were both important factors influencing soil C storage, the models that include only MAP could well explain the variation in soil C storage in the Inner Mongolian grasslands. Because of the high correlation between MAP and MAT in the region, the models including MAT did not significantly enhance the model precision. Moreover, the contribution of the fine fraction （silt and clay） to the variation in soil C storage was rather small because of the very low fine fraction content in the Inner Mongolian grasslands.

关键词： mean annual precipitation mean annual temperature native grassland particle-size fraction soil organic matter

Experimental and numerical investigations of the mechanical behavior of half sandwich laminate in the context of blanking

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Advances in Manufacturing 2020年第2期8卷 177-188页

作者： sheng Cai Lin chen Department of V ehicle Engineering College of EngineeringChina Agricultural UniversityBeijing 100083People's Republic of China CW Bearing GmbH Hamburg 22113Germany

In this study,the complex mechanical behavior of an aluminum/low-density polyethylene(LDPE)half sandwich structure was investigated during the blanking *** tests were conducted for the polymer and metal layer and the delamination behavior of the adhesive between the two layers.A new testing device was designed for detecting the delamination under tensile *** finite element models were established for the mechanical tests of the metal layer and the delamination of both layers for inverse parameter *** parameters for Lemaitre-type damage,Drucker-Prager,and cohesive zone modeIs were identified for the metal,polymer,and adhesive,respectively.A finiteelement(FE)model was established for the blanking process of the sandwich *** experimental forcedisplacement curves,obtained in the blanking process of the half sandwich sheet,were compared with the predicted results of the FE *** results showed that the predicted force-displacement curves and the experimental results were in good ***,the correlation between cutting clearance and changes in the forcedisplacement curves was *** feature values quantitatively described the imperfection of the experimental cutting *** effect of punch clearance on these values was studied numerically and *** results indicated that a smaller clearance generated a better cutting-edge *** stress state of the half sandwich structure during blanking was analyzed using the established FE model.

关键词： Sandwich plates Blanking Continuum damage mechanics(CDM) Drucker-Prager model Cohesive zone model

Parameter identification and blanking simulations of DP1000 and Al6082-T6 using Lemaitre damage model

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Advances in Manufacturing 2021年第3期9卷 457-472页

作者： sheng Cai Lin chen Department of Vehicle Engineering College of EngineeringChina Agricultural UniversityBeijing100083People’s Republic of China CW Bearing GmbH 22113HamburgGermany

This work provides numerical and experimental investigations of blanking process,where the shear-enhanced Lemaitre’s damage model is fully characterized and successfully applied in blanking process to predict the cutting force and cutting edge geometry under different blanking process *** high strength steel DP1000 and an aluminum alloy Al6082-T6 are selected for series of *** obtain the damage parameters in Lemaitre’s damage model the flat rectangular notched specimens tensile test was conducted and the inverse parameter identification procedure was *** characterizing the crack closure parameter h in the shear enhanced Lemaitre’s damage model,an in-plane torsion test with novel specimen design was *** finite element model(FEM)of this test was established with the minimum mesh size of 0.01 mm which was consistent with the minimum mesh size in the shear zone of the FEM for blanking process *** longitudinal strain distributions of four kinds of initial notch radius or central-hole specimen were measured and compared with simulation results to validate the FEMs for these four *** analysis of blanking of a circular work piece also was performed under three *** effects of blanking conditions on sheared part morphology were *** triaxiality distribution of the blank sheet was revealed taking advantage of the successfully established *** availability of the testing method and the determination method of the parameters was investigated.

关键词： Blanking Lemaitre damage model Stress triaxiality Finite element model(FEM)

A novel sort of porous ceramic foam ball with modified surface for arsenic removal from aqueous solution

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Journal of Iron and Steel Research International 2017年第6期24卷 661-668页

作者： Pei-sheng Liu Guang Cui Yi-jiao Guo Jing-he chen Zi-xuan Yang College of Nuclear Science and Technology Beijing Normal University Beijing 100875 China

A sort of lightwerght porous ceramic foam ball that can float on the water was recently made from the nat- ural zeolite. The diameters of porous hall and its macroscopic pores are around 5 and 1 mm, respectively. Such ball surface could be modified to activate in different ways, i. e. loading the active alumina or desili- cating the ball. Both of modified products have been investigated to adsorb the toxic ion of arsenic （As） in water effectively. This kind of porous ceramic hall was prepared by powder sintering, using natural clinop- tilolite powder as the primary raw material. An active-alumina loaded porous ceramic product was genera- ted by sol-gel method with pseudoboehmite （A1OOH） as the main composition. The active AI atom on the porous ball surface could also be achieved by desilicating the ceramic ball in the NaOH solution. Such a desilicated product exhibited a good activity to adsorb the arsenic ion although carrying no ac- tive alumina. With this effective porous structure, the present products can be expected to become practically advantageous.

关键词： Porous materialCeramic foamPorous ceramic ballSurface modificationArsenic removal

Bronchoscopy for diagnosis of COVID-19 with respiratory failure:A case report

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World Journal of Clinical Cases 2021年第5期9卷 1132-1138页

作者： Qing-Yun chen Yu-sheng he Kai Liu Jing Cao Yong-Xing chen Department of Respiratory and Critical Care Medicine Hainan General HospitalHaikou 570311Hainan ProvinceChina Department of Internal Medicine Hainan Province's Fucheng Drug Rehabilitation CentreHaikou 570311Hainan ProvinceChina Infection Department Hainan General HospitalHaikou 570311Hainan ProvinceChina

BACKGROUND Although the imaging features of coronavirus disease 2019(COVID-19)are starting to be well determined,what actually occurs within the bronchi is poorly ***,we report the processes and findings of bronchoscopy in a patient with COVID-19 accompanied by respiratory *** SUMMARY A 65-year-old male patient was admitted to the Hainan General Hospital on February 3,2020 for fever and shortness of breath for 13 d that worsened for the last 2 *** severe acute respiratory syndrome coronavirus 2 nucleic acid test was *** blood examination on February 28 showed a white blood cell count of 11.02×109/L,86.9%of neutrophils,6.4%of lymphocytes,absolute lymphocyte count of 0.71×109/L,procalcitonin of 2.260 ng/mL,and C-reactive protein of 142.61 mg/*** saturation was 46%at baseline and turned to 94%after *** patient underwent video *** tracheal cartilage ring was clear,and no deformity was found in the *** trachea and bilateral bronchi were patent,while the mucosa was with slight hyperemia;no neoplasm or ulcer was *** amounts of white gelatinous secretions were found in the dorsal segment of the left inferior lobe,and the bronchial lumen was patent after sputum *** right inferior lobe was found with hyperemia and mucosal erosion,with white gelatinous secretion *** patient’s condition did not improve after the application of therapeutic *** For patients with COVID-19 and respiratory failure,bronchoscopy can be performed under mechanical ventilation to clarify the airway *** should be worn during the *** the risk of infection,it is not necessary to perform bronchoscopy in the mild to moderate COVID-19 patients.

关键词： COVID-19 Respiratory failure Bronchoscopy Diagnosis Treatment Case report

Hollow glass microspheres/silicone rubber composite materials toward materials for high performance deep in-situ temperaturepreserved coring

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Petroleum Science 2022年第1期19卷 309-320页

作者： Jian-Ping Yang Ling chen Xiao-Bin Gu Zhi-Yu Zhao cheng-Hang Fu Dong-sheng Yang Dong-Zhuang Tian Zhi-sheng chen he-Ping Xie College of Polymer Science and Engineering Sichuan UniversityChengdu610065China Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization Institute of Deep Earth Sciences and Green EnergyCollege of Civil and Transportation EngineeringShenzhen UniversityShenzhen518060China School of Mechanical Engineering Sichuan UniversityChengdu610065China Jinshi Drilltech Company Limited Tangshan063004Hebei Institute of New Energy and Low-Carbon Technology Sichuan UniversityChengdu610065China College of Water Resource&Hydropower Sichuan UniversityChengdu610065China Xi'an Research Institute China Coal Technology&Engineering Group CorpXi'an710077China

Deep petroleum resources are stored under high temperature and pressure conditions,with the temperature having a significant influence on the properties of *** in-situ temperature-preserved coring(ITP-coring)devices were developed to assess deep petroleum reserves ***,hollow glass microspheres(HGMs)/silicone rubber(SR)composites that exhibit excellent thermal insulation properties were prepared as thermal insulation materials for deep ITP-coring *** mechanism and process of heat transfer in the composites were explored,as well as their other *** results show that the HGMs exhibit good compatibility with the SR *** the volume fraction of the HGMs is increased to 50%,the density of the HGMs/SR composites is reduced from 0.97 to 0.56 g/cm^(3).The HGMs filler introduces large voids into the composites,reducing their thermal conductivity to 0.11 W/m·*** addition of HGMs into the composites further enhances the thermal stability of the SR,wherein the higher the HGMs filler content,the better the thermal stability of the *** significantly enhance the mechanical strength of the *** increase the compressive strength of the composites by 828%and the tensile strength by 164%.Overall,HGMs improve the thermal insulation,pressure resistance,and thermal stability of HGMs/SR composites.

关键词： In-situ temperature-preserved coring(ITP-coring) Deep in-situ conditions Thermal insulation materials HGMs/SR composites

Effect of coarse TiN inclusions and microstructure on impact toughness fluctuation in Ti micro-alloyed steel

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Journal of Iron and Steel Research International 2018年第10期25卷 1043-1053页

作者： Tao Liu Mu-jun Long Deng-fu chen Hua-mei Duan Lin-tao Gui sheng Yu Jun-sheng Cao Hua-biao chen he-lin Fan State Key Laboratory of Coal Mine Disaster Dynamics and Control College of Materials Science and Engineering Chongqing University Chongqing 400044 China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials Chongqing University Chongqing 400044 China

Toughness is an important property for steels used in engineering applications. However, recent toughness testing has shown the existence of a significant fluctuation in toughness in a single rolled plate of titanium micro-alloyed steel. The underlying causes of this fluctuation were investigated by fractography, analysis of microstructure and measurement of inclusions. Coarse and distributed TiN inclusions were responsible for the toughness variation, as they tended to act as the potential cleavage initiators to form micro-cracks. From a calculation of the local fracture stress, the critical size of coarse TiN inclusions for dominating micro-crack propagation was 4.93 μm, and similarly that of ferrite grains was 36.6μm. Under current casting and thermo-mechanically controlled processing schedules, the toughness fluctuation of rolled steel plates can be primarily attributed to the fraction of coarse TiN inclusions larger than 5μm. A corresponding relationship between impact energy and the proportion of coarse TiN inclusions was established. Finally, a normalizing treatment was applied to refine the ferrite grains of rolled steel plates. Despite the presence of coarse TiN inclusions, this refinement in ferrite grains minimized the toughness fluctuation and improved the uniformity of the impact properties of the steel plates.

关键词： Impact toughness fluctuation Ti micro-alloyed steel Cleavage fracture Coarse TiN inclusion Grain refinement