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Search Results: 1 - 10 of 126953 matches for " LI Genwei "
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Alien species invasion in Southern China and its countermeasures
我国南方生物入侵的问题与对策

FAN Jihui,JIANG Li,CHENG Genwei,
范继辉

应用生态学报 , 2005,
Abstract: Alien species invasion may cause serious ecological damage,resulting in ecological crisis and biodiversity comedown,and further menacing existing human environment.At present,the invasion of alien species has brought very serious damage to China's environment and society.The direct annual loss of its agro forestry industry accounts for 574 billion RMB.Taking the alien species in Southern China as an example,this paper analyzed the bio invasion approaches,mechanics and damages,and aiming at the characters of invaded area and concerned ecosystems and species,proposed several prevention measurements,i.e.,pay attention to the phenomena of bio invasion and to the basic researches on it; intensify the legislation and establish scientific strategies for introducing alien species; enforce the quarantine on invasive species and establish countrywide monitoring system on alien species; enhance people's defending consciousness; and strengthen international cooperation and collaboration.
On the Variation of NDVI with the Principal Climatic Elements in the Tibetan Plateau
Jian Sun,Genwei Cheng,Weipeng Li,Yukun Sha,Yunchuan Yang
Remote Sensing , 2013, DOI: 10.3390/rs5041894
Abstract: Temperature and precipitation have been separately reported to be the main factors affecting the Normalized Difference Vegetation Index (NDVI) in the Tibetan Plateau. The effects of the main climatic factors on the yearly maximum NDVI (MNDVI) in the Tibetan Plateau were examined on different scales. The result underscored the observation that both precipitation and temperature affect MNDVI based on weather stations or physico-geographical regions. Precipitation is the main climatic factor that affects the vegetation cover in the entire Tibetan Plateau. Both annual mean precipitation and annual mean precipitation of the growing period are related with MNDVI, and the positive correlations are manifested in a linear manner. By comparison, the weakly correlated current between MNDVI and all the temperature indexes is observed in the study area.
The carbon accumulation and dissipation features of sub-alpine woodland in Mt. Gongga

CHENG Genwei,LUO Ji,

地理学报 , 2003,
Abstract: Based on biomass investigations, soil respiration and plant photosynthesis measurement of dominant trees in Hailuogou valley of Mt. Gongga, Southwest China, the carbon (C) storage, absorption and release for several typical woodlands in sub-alpine zones have been discussed. For Abies fabri forest of 3,000 m above sea level, the C storage amount is 177.4 t/ha for above-ground biomass and 143.2 t/ha for soil below-ground biomass. The annual gross C fixed by vegetation photosynthesis is 20-24 t/ha. The C release by canopy respiration is 3.0-5.5 t/ha for arbors and 10-19 t/ha for surface soil and roots. The annual net C fixed of forest ecosystem is about 6.0-7.1 t/ha. At lower elevations, the amount of C released by woodlands is higher than that of woods at higher elevations. The C fixed capacity of renewed forest with middle-aged trees is higher than that of mature forest. Before becoming over-matured forest, woodland is an important sink of C whereas bareland in woods is the source of atmospheric C.
EXPERIMENTAL INVESTIGATION INTO DEFORMATION CHARACTERISTICS OF ANTHRACITE UNDER THERMO-MECHANICAL COUPLING CONDITIONS
热力耦合作用下无烟煤煤体变形特征的试验研究

FENG Zijun,WAN Zhijun,ZHAO Yangsheng,LI Genwei,ZHANG Yuan,WANG Chong,
冯子军
,万志军,赵阳升,李根威,张源,王冲

岩石力学与工程学报 , 2010,
Abstract: 利用自主研制的“600 ℃ 20 MN伺服控制高温高压岩体三轴试验机”系统,研究f200 mm×400 mm大尺寸无烟煤试样在恒定500 m原岩应力状态(轴压12.5 MPa、围压15 MPa),以10 ℃/h的升温速率从20 ℃升至600 ℃过程中的变形规律。试验结果表明:随着温度的升高,无烟煤煤体的变形可分为3个阶段,即20 ℃~200 ℃热膨胀阶段、200 ℃~400 ℃缓慢压缩阶段和400 ℃~600 ℃剧烈压缩阶段。其中,400 ℃~450 ℃为无烟煤煤体变形由脆性机制转变为韧性机制的临界温度范围,温度和压力是影响无烟煤煤体变形脆–韧性转变的主要因素,且具有明显的温压等效性,即较高的临界温度所需转化压力较低。热力耦合作用和热解产气是影响煤体变形的关键因素,尤其在高温阶段,热解产气对变形起到主控作用。
RESEARCH ON GRANITE CUTTING AND BREAKING TEST UNDER CONDITIONS OF HIGH TEMPERATURE AND HIGH PRESSURE
高温高压条件下花岗岩切削破碎试验研究

ZHAO Jinchang,WAN Zhijun,LI Yi,ZHAO Yangsheng,DONG Fuke,FENG Zijun,LI Genwei,
赵金昌
,万志军,李义,赵阳升,董付科,冯子军,李根威

岩石力学与工程学报 , 2009,
Abstract: 为了达到最接近实际工程的试验效果,采用中国矿业大学的“20 MN 伺服控制高温高压岩体三轴试验机”,设计了精确的加压和旋转系统,操作控制比较方便,测量数据准确。利用大尺寸(f 200 mm×400 mm)花岗岩试样和工程钻头(f 30 mm的PDC钻头),使试验条件更加接近实际工程情况,开创了该类大试样试验的先河。通过正交试验研究花岗岩在高温高压状态下的切削破碎规律,得出以下结论:(1) 高围压状态(100 MPa)下,随着温度升高,花岗岩的可切削性逐渐增强,在超过一定的钻压时,切削速度随着温度的升高而明显增大,在755 N钻压下,300 ℃的切削速度比室温时增大30%~50%;(2) 高围压状态(100 MPa)下,随着温度升高,单位破岩能耗明显降低,在钻压为755 N时,300 ℃时的单位破岩能耗比室温时降低20%~30%;(3) 在高温高压环境下,切削速度随着钻压或转速的增大而增大;单位破岩能耗随着转速的增大而增大,随着钻压的增大而减小,与室温无围压状态下的切削破碎规律基本一致;(4) 由于花岗岩在此温压范围内属于渐进破坏,抗压强度下降缓慢,如果钻压太低则切削速度和单位破岩能耗受温度影响很小,为了在高温下取得对花岗岩的良好切削效果,钻压需要超过一定的值。
EXPERIMENTAL STUDY OF PERMEABILITY OF ANTHRACITE AND GAS COAL MASSES UNDER HIGH TEMPERATURE AND TRIAXIAL STRESS
高温三轴应力下无烟煤、气煤煤体渗透特性的试验研究

FENG Zijun,WAN Zhijun,ZHAO Yangsheng,LI Genwei,ZHANG Yuan,WANG Chong,ZHU Nanjing,
冯子军
,万志军,赵阳升,李根威,张源,王冲,朱南京

岩石力学与工程学报 , 2010,
Abstract: 利用自主研制的600 ℃ 20 MN伺服控制高温高压岩体三轴试验机系统,分别研究大尺寸(f200 mm×400 mm)晋城无烟煤和兴隆庄气煤试样在恒定500 m原岩应力(侧压系数1.2)条件下不同温度时渗透特性的演化规律。结果表明:(1) 在室温~300 ℃中低温段,煤体渗透率随温度的变化存在一个阈值温度。当温度达到阈值温度时,渗透率降至最低值。(2) 在300 ℃~600 ℃高温段,煤体渗透率随温度的变化存在一个峰值温度,峰值温度处渗透率为该温度段内的最大值。(3) 煤体渗透率随温度的变化呈现阶段性:室温至阈值温度为第一阶段,渗透率随温度的增加而降低;阈值温度至峰值温度为第二阶段,渗透率随温度的升高而增加;高于峰值温度后,渗透率随温度的增加而降低。(4) 渗透率随温度变化的阈值温度和峰值温度与煤阶有关。无烟煤渗透率的阈值温度是150 ℃~200 ℃,峰值温度为450 ℃~500 ℃,而气煤渗透率的阈值温度为200 ℃~250 ℃。
The Carbon Accumulation and Dissipation Features of Sub-alpine Woodland in Mt. Gongga
贡嘎山亚高山林地碳的积累与耗散特征

CHENG Genwei,LUO Ji,
程根伟
,罗辑

地理学报 , 2003,
Abstract: Based on the biomass investigation, soil respiration and plant photosynthesis measurement of dominant trees in Hailuogou valley of Mt. Gongga, Southwest China, the carbon(C) storage, absorption and release for several typical woodland in sub-alpine zones have been discussed. For Abies fabri forest of 3000 m above sea level, the C storage amount is 177.4 t/hm 2 for plant above ground surface and 143.2 t/hm 2 for soil. The annual gross C fixed by vegetation photosynthesis is 20-24 t/hm 2 . The C release by canopy respiration is 3.0-5.5 t/hm 2 for arbors and 10-19 t/hm 2 for soil and roots. The total annual net C fixed in forest ecosystems is about 6.0-7.1 t/hm 2 . At lower position, the woodland released C amount is higher than that of woods at higher place. The C fixed capacity of renewed forest with middle-aged trees is higher than that of mature forest.
Modeling effects of temperature and precipitation on carbon characteristics and GHGs emissions in Abies fabric forest of subalpine

LU Xuyang,CHENG Genwei,XIAO Feipeng,FAN Jihui,

环境科学学报(英文版) , 2008,
Abstract: Abies fabric forest in the eastern slope of Gongga mountain is one type of subalpine dark coniferous forests of southwestern China.It is located on the southeastern edge of the Qinghai-Tibet plateau and is sensitive to climatic changes,A process-oriented biogeochemical model,Forest-DNDC,was applied to simulate the effects of climatic factors,temperature and precipitation changes on carbon characteristics,and greenhouse gases (GHGs) emissions inA.fabric forest.Validation indicated that the Forest-DNDC could be used to predict carbon characteristics and GHGs emissions with reasonable accuracy.The model simulated carbon fluxes,soil carbon dynamics,soil CO2,N2O,and NO emissions with the changes of temperature and precipitation conditions.The results showed that with variation in the baseline temperature from-2℃ to 2℃,the gross primary production (GPP) and soil organic carbon (SOC)increased,and the net primary production (NPP) and net ecosystem production (NEP) decreased because of higher respiration rate.With increasing baseline precipitation the GPP and NPP increased slightly,and the NEP and SOC showed decreasing trend.Soil CO2 emissions increased with the increase of temperature,and CO2 emissions changed little with increased baseline precipitation.With increased temperature and decreased baseline temperature,the total annual soil N2O emissions increased.With the variation of baseline temperature from -2℃ to 2℃,the total annual soil NO emissions increased.The total annual N2O and NO emissions showed increasing trends with the increase of precipitation.The biogeochemical simulation of the typical forest indicated that temperature changes strongly affected carbon fluxes,soil carbon dynamics,and soil GHGs emissions.The precipitation was not a principal factor affecting carbon fluxes,soil carbon dynamics,and soil CO2 emissions,but changes in precipitation could exert strong effect on soil N2O and NO emissions.
Characteristics of soil water infiltration in sub-alpine dark coniferous ecosystem of upper reaches of Yangtze River
长江上游亚高山暗针叶林土壤水分入渗特征研究

YU Xinxiao,ZHAO Yutao,ZHANG Zhiqiang,CHENG Genwei,
余新晓
,程根伟,

应用生态学报 , 2003,
Abstract: Dark coniferous forest is the predominant type of vegetation in the upper reaches of Yangtze River. Difference among different types of soil exists. The sand content of soil is higher and the soil texture is coarser in the early stage of forest succession. The sand content of soil decreases with the advancement of the forest succession while that of soil in Abies fabri over-mature forest is the lowest. In slope wash soil, the sand content of soil decreases with the increasing soil depth. The soil porosity and soil water-holding capacity increases and soil bulk density decreases with the advancement of forest succession and decrease of soil depth. The deeper soil depth or the smaller soil water content are, the smaller the unsaturated hydraulic conductivity of soil measured by CGA method. Moreover, the correlation of soil water content with unsaturated hydraulic conductivity of soil can be simulated by an exponential function. The saturated hydraulic conductivity of soil decreases exponentially with the increasing soil depth. The time to attain the stable infiltration rate is different among different soil depth, while the deeper the soil depth is, the longer the time needs. The variation in soil texture, soil physical properties and the high infiltration rate of soil there implicated that there are scarce surface runoff, but aboundant in subsurface flow, return flow and seepage, which is the result of regulation by dark coniferous forest on hydrological processes.
Beneficial Experience from Teaching and Education to Research and Development  [PDF]
Li Li
Creative Education (CE) , 2012, DOI: 10.4236/ce.2012.37B039
Abstract:

Teaching and Education (T&E) constitute the most important activity in knowledge transfer from generation to generation. This can explain why government organizations consider the training of highly qualified personnel as one of the most important criteria in the selection of research and development (R&D) grant applications. A university professor should thus not only play the role of researcher, but also that of teacher. T&E and R&D combine to form an inseparable relationship for university professors. By shooting for excellence in T&E, we could get a new perception of a familiar field or initiate a brand new field altogether, which would in turn enhance our research. The quest for excellence in R&D leads to deeper and better understanding of materials taught, and progress in R&D enriches our T&E endeavors. Here, the author shares a beneficial experience from T&E to R&D.

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