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Characterizing long-term forest disturbance history and its drivers in the Ning-Zhen Mountains, Jiangsu Province of eastern China using yearly Landsat observations (1987–2011)

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Journal of Forestry Research 2016年第6期27卷 1329-1341页

作者： Mingshi Li Chengquan Huang Wenjuan Shen Xinyu Ren Yingying Lv Jingrui Wang Zhiliang Zhu College of Forestry Nanjing Forestry UniversityLongpan Road 159Nanjing 210037People's Republic of China Co-innovation center for Sustainable Forestry in Southern China Nanjing Forestry UniversityNanjingPeople's Republic of China Department of Geographical Sciences University of Maryland2181 LeFrak HallCollege ParkMD 20742USA USGS Headquarter 12201 Sun Rise Valley DriveRestonVA 20192USA

Forest losses or gains have long been recognized as critical processes modulating the carbon flux between the biosphere and the atmosphere. Timely, accurate and spatially explicit information on forest disturbance and recovery history is required for assessing the effectiveness of existing forest management. The major objectives of our research focused on testing the mapping efficacy of the vegetation change tracker （VCT） model over a forested area in China. We used a new version of VCT algorithm built upon the Landsat time series stacks （LTSS）. The LTSS consisted of yearly image acquisitions to map forest disturbance history from 1987 to 2011 over the Ning-Zhen Mountains, Jiangsu Province of east China. The LTSS consisted of TM and ETM＋ scenes with different projec- tions due to distinct data sources （Beijing remote sensing ground station and the USGS EROS center）. The valida- tion results of the disturbance year maps showed that most spatial agreement measures ranged from 70 to 86 %, comparable with the VCT accuracies reported for many places in USA. Very low accuracies were identified in 1995 （38.3 %） and 1992 （56.2 %） in the current analysis. These resulted from the insensitivity of the VCT algorithm to detect low intensity disturbances and also from the mis- registration errors of the image pairs. Major forest distur- bance types existing in our study area were identified as agricultural expansion （39.8 %）, urbanization （24.9 %）, forest management practice （19.3 %）, and mining （12.8 %）. In general, there was a gradual decreasing trend in forest cover throughout this region, caused principally by China＇s economic, demographic, environmental and political policies and decisions, as well as some weather events. While VCT has largely been used to assess long term changes and trends in the USA, it has great potential for assessing landscape level change elsewhere throughout the world.

关键词： Landsat time series stack LEDAPS - Forest disturbance VCT model

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2D hetero-structures based on transition metal dichalcogenides:fabrication,properties and applications

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Science Bulletin 2017年第16期62卷 1148-1161页

作者： Ping Liu Bin Xiang Department of Materials Science&Engineering CAS Key Lab of Materials for Energy Conversionand Synergetic Innovation Center of Quantum Information&Quantum PhysicsUniversity of Science and Technology of ChinaHefei 230026China

Recently,two dimensional transition metal dichalcogenides MX_2(M = Mo,W,etc; X = S,Se,Te) have ignited immense interests because of their unique structural and physical properties for the potential applications in the nano-optoelectronics,valley-spintronics etc. In terms of the structural compatibility and van der Waals interaction,two dimensional(2D) MX_2 layers can be fabricated into various lateral and vertical hetero-structures. The atomically-thin hetero-structures comprising different layered MX_2 provide a new platform for exploring fundamental physics and device technologies with unprecedented phenomenon and extraordinary functionalities. In this review,we report the recent progress about the fabrication,properties and applications of 2D hetero-structures based on transition metal dichalcogenides.

关键词： Transition metal dichalcogenides Hetero-structures Chemical vapor deposition Charge transfer Optoelectronic devices

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Potential Areas for Managed Aquifer Recharge in the Eastern Lower jordan valley Area

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Journal of Water Resource and Protection 2020年第4期12卷 330-357页

作者： Elias Salameh Ghaida Abdallat National center for Research and Development (NCRD) Amman Jordan

The article deals with the feasibility of using the recent geological formations in the eastern jordan valley for water storage through artificial recharge due to water scarcity and water needs in this area. Water storage in surface reservoirs in arid and semi-arid areas is afflicted with a variety of issues such as high evaporation, eutrophication processes and exposure to contamination and accidents. Dams to capture all rare-event floods are, generally, big and expensive structures. Artificially recharging aquifers and storing the water in the underground offer a competing alternative. In this study, hydrogeological, geological, geophysical and hydrochemical investigations were carried out to study the potentials of the eastern side of the Lower jordan valley for artificial recharge. The results reveal that relatively extended areas on the eastern side of the Lower jordan valley have the potential to accommodate large amounts of recharge water and that the impacts of artificially storing the water in aquifers are to be judged very positive compared to surface storage, especially when the amounts of available recharge water can quantitatively be accommodated in recharge facilities. In addition, the study shows, the advantages of underground water storage compared to surface storage in dams. The potential storage capacities in the different parts of the Lower jordan valley are quantified based on rechargeable aquifer volumes and porosities. The potential uses of the recharged water are also elaborated on depending on recharge and aquifer water qualities.

关键词： Managed Aquifer Recharge (MAR) jordan valley Potential Storage Hydrogeological Conditions

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Linear and nonlinear characteristics of time-resolved photoluminescence modulation by terahertz pulse

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Chinese Physics B 2017年第10期26卷 1-6页

作者：龚姣丽刘劲松张曼褚政杨振刚王可嘉姚建铨 Wuhan National Laboratory for Optoelectronics School of Optical and Electronic InformationHuazhong University of Science and Technology Hubei Collaborative innovation center for High-efficient Utilization of Solar Energy School of ScienceHubei University of Technology

The linear and nonlinear characteristics of time-resolved photoluminescence （PL） of n-type bulk semiconductor GaAs modulated with terahertz （THz） pulse are studied by using an ensemble Monte Carlo （EMC） method. In this paper the center energy valley （Г valley） electron concentration changes with the pulse delay time, sampling time and the outfield are mainly discussed. The results show that the sampling time and the THz field should exceed certain thresholds to effectively excite photoluminescence quenching （PLQ）. Adopting a direct current （DC） field makes the sampling time threshold shortened and the linear range of THz field-modulation PL expanded. Moreover, controlling the sampling time and the outfield intensity can improve the linear quality： with forward time, the larger outfield is used; with backward time, the smaller outfield is used. This study can provide a theoretical basis of THz field linear modulation in a larger range for new light emitting devices.

关键词： THz pulse modulation photoluminescence ensemble Monte Carlo intervalley scattering

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Review of ultrafast spectroscopy studies of valley carrier dynamics in two-dimensional semiconducting transition metal dichalcogenides

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Chinese Physics B 2017年第3期26卷 148-159页

作者：孙栋赖佳伟马骏超王钦生刘晶 International center for Quantum Materials School of Physics Peking University Beijing 100871 China Collaborative innovation center of Quantum Matter Beijing 100871 China State Key Laboratory of Precision Measurement Technology and Instruments School of Precision Instruments and Optoelectronic Engineering Tianjin University Tianjin 300072 China

The two-dimensional layered transition metal dichalcogenides provide new opportunities in future valley-based in- formation processing and also provide an ideal platform to study excitonic effects. At the center of various device physics toward their possible electronic and optoelectronic applications is understanding the dynamical evolution of various many- particle electronic states, especially exciton which dominates the optoelectronic response of TMDs, under the novel con- text of valley degree of freedom. Here, we provide a brief review of experimental advances in using helicity-resolved ultrafast spectroscopy, especially ultrafast pump-probe spectroscopy, to study the dynamical evolution of valley-related many-particle electronic states in semiconducting monolayer transitional metal dichalcogenides.

关键词： ultrafast spectroscopy valley carrier dynamics transition metal dichalcogenides exciton

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Influence of the velocity barrier on the massive Dirac electron transport in a monolayer MoS2 quantum structure

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Frontiers of physics 2020年第3期15卷 113-121页

作者： X.-J.Hao R.-Y.Yuan J.-J.Jin Y.Guo center for Theoretical Physics Department of PhysicsCapital Normal UniversityBeijing100048China Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics Tsinghua UniversityBeijing100084China Collaborative innovation center of Quantum Matter BeijingChina

Using the transfer matrix method,spin-and valley-dependent electron transport properties modulated by the velocity barrier were studied in the normal/ferromagnetic/normal monolayer MoS2 quantum *** on Snell’s Law in optics,we define the velocity barrier asξ=v2/v1 by changing the Fermi velocity of the intermediate ferromagnetic region to obtain a deflection condition during the electron transport process in the *** results show that both the magnitude and the direction of spin-and valley-dependent electron polarization can be regulated by the velocity barrier.−100%polarization of spin-and valley-dependent electron can be achieved forξ>1,while 100%polarization can be obtained forξvalley transport always occur at a large incident *** addition,the spin-and valley-dependent electron transport considerably depends on the length kFL and the gate voltage U(x)of the intermediate ferromagnetic *** findings provide an effective method for designing novel spin and valley electronic devices.

关键词： velocity barrier monolayer MoS2 spin valley polarization

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Effects of Nitrogen Application Levels on Ammonia Volatilization and Nitrogen Utilization during Rice Growing Season

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Rice science 2012年第2期19卷 125-134页

作者： LIN Zhong-cheng DAI Qi-gen YE Shi-chao WU Fu-guan JIA Yu-shu CHEN Jing-dou XU Lu-sheng ZHANG Hong-cheng Huo Zhong-yang Xu Ke WEt Hai-yan Key Laboratory of Crop Genetics and Physiology of Jiangsu Province / innovation center of Rice Cultivation Technology in Yangtze valley Ministry of Agriculture Yangzhou University Yangzhou 225009 China Agriculture Committee of Wujiang County Jiangsu Province Wujiang 215200 China Agriculture Bureau of Guannan County Jiangsu Province Guannan 222500 China

We conducted field trials of rice grown in sandy soil and clay soil to determine the effects of nitrogen application levels on the concentration of NH4＋-N in surface water, loss of ammonia through volatilization from paddy fields, rice production, nitrogen-use efficiency, and nitrogen content in the soil profile. The concentration of NH4＋-N in surface water and the amount of ammonia lost through volatilization increased with increasing nitrogen application level, and peaked at 1-3 d after nitrogen application. Less ammonia was lost via volatilization from clay soil than from sandy soil. The amounts of ammonia lost via volatilization after nitrogen application differed depending on the stage when it was applied, from the highest loss to the lowest： N application to promote tillering 〉 the first N topdressing to promote panicle initiation （applied at the last 4-leaf stage）〉 basal fertilizer 〉 the second N topdressing to promote panicle initiation （applied at the last 2-leaf stage）. The total loss of ammonia via volatilization from clay soil was 10.49-87.06 kg/hm2, equivalent to 10.92%-21.76% of the nitrogen applied. The total loss of ammonia via volatilization from sandy soil was 11.32-102.43 kg/hm2, equivalent to 11.32%-25.61 % of the nitrogen applied. The amount of ammonia lost via volatilization and the concentration of NH4＋-N in surface water peaked simultaneously after nitrogen application; both showed maxima at the tillering stage with the ratio between them ranging from 23.76% to 33.65%. With the increase in nitrogen application level, rice production and nitrogen accumulation in plants increased, but nitrogen-use efficiency decreased. Rice production and nitrogen accumulation in plants were slightly higher in clay soil than in sandy soil. In the soil, the nitrogen content was the lowest at a depth of 40-50 cm. In any specific soil layer, the soil nitrogen content increased with increasing nitrogen application level, and the soil nitrogen content was higher in

关键词： ammonia volatilization nitrogen application level soil type nitrogen-use efficiency rice

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GWAS identifies candidate genes controlling adventitious rooting in Populus trichocarpa

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Horticulture Research 2023年第8期10卷 97-108页

作者： Michael F.Nagle Jialin Yuan Damanpreet Kaur Cathleen Ma Ekaterina Peremyslova Yuan Jiang Bahiya Zahl Alexa Niño de Rivera Wellington Muchero Li Fuxin Steven H.Strauss Department of Forest Ecosystems and Society Oregon State University3180 SW Jefferson WayCorvallisOR97331United States Department of Electrical Engineering and Computer Science Oregon State University110 SW Park TerraceCorvallisOR97331United States Statistics Department Oregon State University103 SW Memorial PlaceCorvallisOR97331United States Biosciences Division Oak Ridge National Laboratory1 Bethel Valley RdOak RidgeTN37830United States center for Bioenergy innovation Oak Ridge National Laboratory1 Bethel Valley RdOak RidgeTN37830United States Bredesen center for Interdisciplinary Research University of Tennessee821 Volunteer Blvd.KnoxvilleTN37996United States

Adventitious rooting(AR)is critical to the propagation,breeding,and genetic engineering of *** capacity for plants to undergo this process is highly heritable and of a polygenic nature;however,the basis of its genetic variation is largely *** identify genetic regulators of AR,we performed a genome-wide association study(GWAS)using 1148 genotypes of Populus *** are often limited by the abilities of researchers to collect precise phenotype data on a high-throughput scale;to help overcome this limitation,we developed a computer vision system to measure an array of traits related to adventitious root development in poplar,including temporal measures of lateral and basal root length and *** was performed using multiple methods and significance thresholds to handle non-normal phenotype statistics and to gain statistical *** analyses yielded a total of 277 unique associations,suggesting that genes that control rooting include regulators of hormone signaling,cell division and structure,reactive oxygen species signaling,and other processes with known roles in root *** genes with uncharacterized functions and/or cryptic roles were also *** candidates provide targets for functional analysis,including physiological and epistatic analyses,to better characterize the complex polygenic regulation of AR.

关键词： GWAS breeding overcome

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Numerical investigation on adiabatic film cooling effectiveness and heat transfer coefficient for effusion cooling over a transverse corrugated surface

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Chinese Journal of Aeronautics 2017年第2期30卷 677-684页

作者： Qu Lihong Zhang Jingzhou Tan Xiaoming Wang Minmin College of Energy and Power Engineering Jiangsu Province Key Laboratory of Aerospace Power System Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Collaborative innovation center of Advanced Aero-Engine Beijing 100083 China

Three-dimensional numerical computations are conducted to investigate the effects of the blowing ratio and corrugation geometry on the adiabatic film cooling effectiveness as well as the heat transfer coefficient over a transverse corrugated *** is noticeable that the adiabatic wall temperature on the wavy valley of the transverse corrugated surface is relatively lower than that on the wavy *** corrugation has a relatively obvious influence on the laterallyaveraged adiabatic film cooling effectiveness in the region where the effusion film layer is developed,but has little influence in the front *** to a flat surface,the transverse corrugated surface produces a smaller adiabatic film cooling effectiveness and a higher heat transfer coefficient *** effusion cooling difference between the flat and corrugated surfaces behaves more obviously under a small aspect ratio of the wavy corrugation.

关键词： Adiabatic film cooling effectiveness Effusion cooling Heat transfer Numerical computation Transverse corrugated surface

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Knowledge and learning in the horticultural innovation system: A case of Kashmir valley of India

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International Journal of innovation Studies 2020年第4期4卷 116-133页

作者： Sheeraz Ahmad Alaie center for Studies in Science Technology and Innovation PolicyCentral University of GujaratGandhinagar.Sector 30Gandhinagar382030India

The system of innovation(SI)in the agriculture sector,termed as Agricultural innovation System(AIS),is one of the most recent trends in innovation research,especially in the developing *** approach considers several factors such as actors,complex networks and learning,socio-cultural and political factors that affect the innovation process within a dynamic *** the AIS approach,the present paper explores the knowledge and learning interactions in the horticultural sector of Kashmir valley of India,which offers a mix of both formal and informal *** research methodology is qualitative in nature based on both primary and secondary *** primary data collection,apple growers,private and government sector actors were interviewed and secondary data is based on various reports and published materials related to the apple production in *** analysis explores the interactions of knowledge production by formal and informal means in the horticultural sector specifically focusing on the informal *** the study,taking the case of canker disease treatment in apple trees by informal ways depicts the productive use of informal knowledge in the horticultural *** was observed that many factors(social networks,life-long experiences,learning,coordination and group interactions)affect the informal knowledge generation process and the connectivity between formal and informal actors is lagging in the horticulture sector.

关键词： Agricultural innovations system Informal sector innovation Knowledge Horticulture India

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