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Distribution Prediction of Suitable Growth Area for Eucommia ulmoides in China under Climatic Change Background 被引量:3
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作者 Yang Liu 《Meteorological and Environmental Research》 CAS 2013年第8期21-24,共4页
[ Objective] The research aimed to study distribution prediction of suitable growth area for Eucommia ulmoides in China under climatic change background. [ Method] By using the maximum entropy model and many kinds of ... [ Objective] The research aimed to study distribution prediction of suitable growth area for Eucommia ulmoides in China under climatic change background. [ Method] By using the maximum entropy model and many kinds of climate change scenarios, we predicted current and future distribution pattems of suitable growth area for Eucommia ulmoides in China and its change process. [ Result ] At present, highly suitable growth area of E. ulmoides mainly distributed in Sichuan, Shaanxi and Chongqing, Under climate change background, total suitable growth areas in future three decades all drastically reduced when compared with that at present. It was noteworthy that moderately and highly suitable growth areas of wild E. ulmoides all disappeared, and junction between Shaanxi and Gansu and Taibai Mountain would be stable suitable growth area of wild E. ulmoides. [ Condusioa] The research could provide useful reference data for investigation, protection and sustainable development of the wild E. ulmoides resources. 展开更多
关键词 E. ulmoides Suitable growth area Climate change The maximum entropy model Distribution prediction China
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Selective Area Growth and Characterization of GaN Nanorods Fabricated by Adjusting the Hydrogen Flow Rate and Growth Temperature with Metal Organic Chemical Vapor Deposition 被引量:1
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作者 任鹏 韩刚 +6 位作者 付丙磊 薛斌 张宁 刘喆 赵丽霞 王军喜 李晋闽 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第6期145-149,共5页
CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen (H2)/nitrogen (N2) and growth temperature of the selective area growth (SAG) method with metal organic chemical vapor deposit... CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen (H2)/nitrogen (N2) and growth temperature of the selective area growth (SAG) method with metal organic chemical vapor deposition (MOCVD). The SAG template is obtained by nanospherical-lens photolithography. It is found that increasing the flow rate of 1-12 will change the CaN crystal shape from pyramid to vertical rod, while increasing the growth temperature will reduce the diameters of GaN rods to nanometer scale. Finally the CaN nanorods with smooth lateral surface and relatively good quality are obtained under the condition that the H2:N2 ratio is 1:1 and the growth temperature is 1030℃. The good crystal quality and orientation of GaN nanorods are confirmed by high resolution transmission electron microscopy. The cathodoluminescence spectrum suggests that the crystal and optical quality is also improved with increasing the temperature. 展开更多
关键词 of or IS as RATE GAN Selective area growth and Characterization of GaN Nanorods Fabricated by Adjusting the Hydrogen Flow Rate and growth Temperature with Metal Organic Chemical Vapor Deposition by with
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Growth Characteristics and Resource Evaluation of Sebastes schlegelii in Zhangzidao Artificial Reef Area 被引量:1
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作者 Yin Zengqiang Lu Wanqiao +5 位作者 Chen Yong Liu Yonghu Zhou Shuanlin Meng Weidong Yang Jun Tian Tao 《Animal Husbandry and Feed Science》 CAS 2016年第3期186-188,共3页
[Objective]The paper was to formulate catchable size and total allowable catch of Sebastes schlegelii in Zhangzidao artificial reef area.[Method]Based on analysis of length-weight formula,body length and weight growth... [Objective]The paper was to formulate catchable size and total allowable catch of Sebastes schlegelii in Zhangzidao artificial reef area.[Method]Based on analysis of length-weight formula,body length and weight growth equations,and instantaneous mortality rate,the inflection age and critical age of weight growth were calculated,and the biomass of S.schlegelii in Zhangzidao artificial reef area was estimated.[Result]The growth equation of body length was Lt=412.5×[1-e^-0.21(t+0.65)]and the growth equation of body weight was Wt=1 734.2×[1-e^-0.21(t+0.65)]^2.92.The inflection age and critical age for weight growth of S.schlegelii were 4.45 and 4.82 a,respectively.The biomass in Zhangzidao artificial reef area was about 456.8 t.[Conclusion]For S.schlegelii flock in Zhangzidao artificial reef area,the catchable length was about 271.2-281.7 mm,the catchable weight as about 509.4-569.5 g,and the total allowable catch was about 60.43 t. 展开更多
关键词 Sebastes schlegelii growth equation Critical age Biomass Dalian sea area
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Fabrication of 32 Gb/s Electroabsorption Modulated Distributed Feedback Lasers by Selective Area Growth Technology
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作者 周代兵 王会涛 +8 位作者 张瑞康 王宝军 边静 安欣 陆丹 赵玲娟 朱洪亮 吉晨 王圩 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第5期66-68,共3页
A 32 Gb/s monolithically integrated electroabsorption modulated laser is fabricated by selective area growth technology. The threshold current of the device is below 13mA. The output power exceeds 10mW at 0V bias when... A 32 Gb/s monolithically integrated electroabsorption modulated laser is fabricated by selective area growth technology. The threshold current of the device is below 13mA. The output power exceeds 10mW at 0V bias when the injection current of the distributed feedback laser is 100mA at 25℃. The side mode suppression ratio is over 50 dB. A 32Gb/s eye diagram is measured with a 3.SVpp nonreturn-to-zero pseudorandom modulation signal at -2.3 V bias. A clearly opening eyediagram with a dynamic extinction ratio of 8.01 dB is obtained. 展开更多
关键词 Fabrication of 32 Gb/s Electroabsorption Modulated Distributed Feedback Lasers by Selective area growth Technology EML EAM DFB InGaAs SAG
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Controlled Growth of Large-Area Aligned Single-Crystalline Organic Nanoribbon Arrays for Transistors and Light-Emitting Diodes Driving 被引量:1
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作者 Wei Wang Liang Wang +4 位作者 Gaole Dai Wei Deng Xiujuan Zhang Jiansheng Jie Xiaohong Zhang 《Nano-Micro Letters》 SCIE EI CAS 2017年第4期193-203,共11页
Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, l... Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, low-cost organic electronic applications. However, fabrication of large-area organic micro-/nanocrystal arrays with consistent crystal growth direction has posed a significant technical challenge. Here, we describe a solution-processed dip-coating technique to grow large-area, aligned 9,10-bis(phenylethynyl) anthracene(BPEA) and 6,13-bis(triisopropylsilylethynyl) pentacene(TIPSPEN) single-crystalline nanoribbon arrays. The method is scalable to a 5 9 10 cm^2 wafer substrate, with around 60% of the wafer surface covered by aligned crystals. The quality of crystals can be easily controlled by tuning the dip-coating speed. Furthermore, OFETs based on well-aligned BPEA and TIPS-PEN single-crystalline nanoribbons were constructed.By optimizing channel lengths and using appropriate metallic electrodes, the BPEA and TIPS-PEN-based OFETs showed hole mobility exceeding 2.0 cm^2V^(-1)s^(-1)(average mobility 1.2 cm^2V^(-1)s^(-1)) and 3.0 cm^2V^(-1)s^(-1)(average mobility2.0 cm^2V^(-1)s^(-1)), respectively. They both have a high on/off ratio(I_(on)/I_(off))>10~9. The performance can well satisfy the requirements for light-emitting diodes driving. 展开更多
关键词 Large-area growth Organic single-crystalline nanoribbon arrays Organic field-effect transistors Light-emitting diodes driving
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Selective Area Growth of GaAs in V-Grooved Trenches on Si(001) Substrates by Aspect-Ratio Trapping
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作者 李士颜 周旭亮 +5 位作者 孔祥挺 李梦珂 米俊萍 边静 王伟 潘教青 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第2期148-151,共4页
A high quality of GaAs crystal growth in nanoscale V-shape trenches on Si(O01) substrates is achieved by using the aspect-ratio trapping method. GaAs thin films are deposited via metal-organic chemical vapor deposit... A high quality of GaAs crystal growth in nanoscale V-shape trenches on Si(O01) substrates is achieved by using the aspect-ratio trapping method. GaAs thin films are deposited via metal-organic chemical vapor deposition by using a two-step growth process. Threading disJocations arising from lattice mismatch are trapped by laterally confining sidewalls, and antiphase domains boundaries are completely restricted by V-groove trenches with Si { 111} facets. Material quality is confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution X-ray diffraction. Low temperature photoluminescence (PL) measurement is used to analyze the thermal strain relaxation in GaAs layers. This approach shows great promise for the realization of high mobility devices or optoelectronie integrated circuits on Si substrates. 展开更多
关键词 Selective area growth of GaAs in V-Grooved Trenches on Si Substrates by Aspect-Ratio Trapping
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Estimation of a basal area growth model for individual trees in uneven-aged Caspian mixed species forests 被引量:1
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作者 Zohreh Mohammadi Soleiman Mohammadi Limaei +1 位作者 Peter Lohmander Leif Olsson 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第5期1205-1214,共10页
The aim of this study was to estimate a basal area growth model for individual trees in uneven-aged Caspian forests.A survey was conducted in order to find a natural forest without any harvesting activities,a so call... The aim of this study was to estimate a basal area growth model for individual trees in uneven-aged Caspian forests.A survey was conducted in order to find a natural forest without any harvesting activities,a so called 'untouched forest' and an area was selected from the Iranian Caspian forest.Three sample plots in the same aspect and of the same forest type were selected.In each plot,total tree height,diameter at breast height,distance of neighbor trees and azimuth were measured.Thirty trees were selected and drilled with increment borer to determine the increment model.Regression analysis was used to estimate the growth model.Results show that,for individual trees,there is a significant nonlinear relationship between the annual basal area increment,as the dependent variable,and the basal area.The results also show that the basal area of competing trees has a positive influence on growth.That the increment is higher with more competing neighboring trees is possibly because plots with higher volume per hectare and more competition,most likely also have higher site index or better soil or better site productivity than the plot with lower volume per hectare. 展开更多
关键词 Basal area increment Diameter growth Regression analysis Caspian forests
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Five Areas for Sustained High Economic Growth in China
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《China's Foreign Trade》 1999年第7期17-17,共1页
Afierhavingexperiencedtwodecadesofsustainedhigh.economicqrnwthwillithppossibleforChinatoseecontinuedsustainedhigheconomicgrowthinanother10to20years?Followingtheeconomicslowdowninthepastfewyears,manyholdpessimisticview... Afierhavingexperiencedtwodecadesofsustainedhigh.economicqrnwthwillithppossibleforChinatoseecontinuedsustainedhigheconomicgrowthinanother10to20years?Followingtheeconomicslowdowninthepastfewyears,manyholdpessimisticviewsonthis.Inaninterviewwithacorresp... 展开更多
关键词 Five areas for Sustained High Economic growth in China
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Analysis on Change Tendency of the Precipitation Resource during Growth Period of the Conventional Crops in Plain Area before Taihang Mountains
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作者 Suqing Han Shijing Jia 《Meteorological and Environmental Research》 CAS 2013年第2期49-52,共4页
[Objective] The aim was to study change tendency of the precipitation resource during growth period of the conventional crops in plain area before Taihang Mountains. [ Method] Based on daily precipitation data at Shij... [Objective] The aim was to study change tendency of the precipitation resource during growth period of the conventional crops in plain area before Taihang Mountains. [ Method] Based on daily precipitation data at Shijiazhuang meteorological station in recent 51 years, average rainfall dudng growth periods of the 9 kinds of conventional crops was obtained. Precipitation tendency dudng growth periods of the 9 kinds of conventional crops in plain area before Taihang Mountains was analyzed by Mann-Kendall nonparametric test. [ Result] Seen from rainfall during growth pedods of the different crops, rainfall was the least during the growth period of winter wheat, followed by summer corn. Rainfall during growth peri- ods of the cotton, oil plant, vegetable, fruit tree, potato, rice and legumes was more. Under different guaranteed rates, precipitation change also had difference. Rainfall change during growth periods of the wheat and corn was bigger, and rainfall change during growth period of the rice was smaller. Change degree of the precipitation during growth periods of the cotton, oil plant, vegetable, fruit tree and legumes was equivalent, while precipitation change during growth period of the potato was the biggest. Seen from change tendency of the precipitation during growth periods of the different crops, precipitation in the growth period of winter wheat was increasing at a speed of 0.62 mm/a. However, precipitation in growth periods of the other crops had a decreasing tendency. Precipitation in the growth periods of summer corn and legumes decreased at the same speed which was 2.11 mm/a, while precipitation in growth periods of the cotton, oil plant, vegetable, fruit tree, potato and rice decreased insignificantly. [ Con dusion] The study laid foundation for determination of the agricultural irrigation water and provided theoretical reference for regional agricultural water-saving. 展开更多
关键词 Precipitation resource Conventional crops growth period Change trend Plain area before Taihang Mountains China
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1.5μm Self-Aligned Spotsize Converter Integrated DFB Fabricated by Selective Area Grown MOVPE
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作者 邱伟彬 董杰 +1 位作者 王圩 周帆 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第7期681-684,共4页
High performance 1 57μm spotsize converter monolithically integrated DFB is fabricated by the technique of self aligned selective area growth.The upper optical confinement layer and the butt coupled tapered thickn... High performance 1 57μm spotsize converter monolithically integrated DFB is fabricated by the technique of self aligned selective area growth.The upper optical confinement layer and the butt coupled tapered thickness waveguide are regrown simultaneously,which not only offeres the separated optimization of the active region and the integrated spotsize converter,but also reduces the difficulty of the butt joint selective regrowth.The threshold current is as low as 4 4mA.The output power at 49mA is 10 1mW.The side mode suppression ratio (SMSR) is 33 2dB.The vertical and horizontal far field divergence angles are as small as 9° and 15° respectively,the 1dB misalignment tolerance are 3 6μm and 3 4μm. 展开更多
关键词 spotsize converter self aligned butt joint selective area growth
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Vegetation changes in the agricultural-pastoral areas of northern China from 2001 to 2013 被引量:6
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作者 SU Wei YU De-yong +3 位作者 SUN Zhong-ping ZHAN Jun-ge LIU Xiao-xuan LUO Qian 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2016年第5期1145-1156,共12页
Climate change and human activity have resulted in increasing change of vegetation growth globally. Numerous studies have been conducted on extreme climate events and analyses of ecological environment evolution. Howe... Climate change and human activity have resulted in increasing change of vegetation growth globally. Numerous studies have been conducted on extreme climate events and analyses of ecological environment evolution. However, such studies have placed little emphasis on vegetation change and spatial variation in this type of ecotone. Accordingly, this study analyzed the changes in vegetation type and growth using the 16-d composite MOD13A1 product with 1-km resolution and MOD12Q1 product with 1-km resolution. We used the mean, maximum, standard deviation normalized-difference vegetation index(NDVI) values, and the rate of change(ROC) of NDVI value to explain vegetation changes within the studied ecotone. Our results showed that significant vegetation type and growth changes have occurred in the study area. From 2001 to 2013, for example, with the exception of 2001, 2004 and 2009, a certain extent of grassland area was converted to cropland. Drought severity index(DSI) results indicate that there exists drought in 2001, 2004 and 2009. Such temporal changes in cropland and grassland area confirmed the ecological vulnerability of the ecotone. At the same time, vegetation varied spatially from west to east and from south to north. The mean, maximum and standard deviation NDVI values were all sorted in descending order based on differences in latitude and longitude, as follows: NDVI_(2013)〉NDVI_(2009)〉NDVI_(2004)〉NDVI_(2001) 展开更多
关键词 vegetation growth agricultural-pastoral area MODIS land cover change temporal change spatial variation
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Effects of Crop Growth and Development on Land Surface Fluxes 被引量:4
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作者 陈锋 谢正辉 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2011年第4期927-944,共18页
In this study, the Crop Estimation through Resource and Environment Synthesis model (CERES3.0) was coupled into the Biosphere-Atmosphere Transfer Scheme (BATS), which is called BATS CERES, to represent interaction... In this study, the Crop Estimation through Resource and Environment Synthesis model (CERES3.0) was coupled into the Biosphere-Atmosphere Transfer Scheme (BATS), which is called BATS CERES, to represent interactions between the land surface and crop growth processes. The effects of crop growth and development on land surface processes were then studied based on numerical simulations using the land surface models. Six sensitivity experiments by BATS show that the land surface fluxes underwent substantial changes when the leaf area index was changed from 0 to 6 m2 m-2. Numerical experiments for Yucheng and Taoyuan stations reveal that the coupled model could capture not only the responses of crop growth and development to environmental conditions, but also the feedbacks to land surface processes. For quantitative evaluation of the effects of crop growth and development on surface fluxes in China, two numerical experiments were conducted over continental China: one by BATS CERES and one by the original BATS. Comparison of the two runs shows decreases of leaf area index and fractional vegetation cover when incorporating dynamic crops in land surface simulation, which lead to less canopy interception, vegetation transpiration, total evapotranspiration, top soil moisture, and more soil evaporation, surface runoff, and root zone soil moisture. These changes are accompanied by decreasing latent heat flux and increasing sensible heat flux in the cropland region. In addition, the comparison between the simulations and observations proved that incorporating the crop growth and development process into the land surface model could reduce the systematic biases of the simulated leaf area index and top soil moisture, hence improve the simulation of land surface fluxes. 展开更多
关键词 crop growth and development leaf area index land surface model land surface fluxes
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Filtering bleb area and intraocular pressure following subconjunctival injection of CTGF antibody after glaucoma filtration surgery in rabbits 被引量:2
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作者 Jian-Ming Wang Na Hui +2 位作者 Ya-Zhi Fan Lei Xiong and Nai-Xue Sun 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2011年第5期480-483,共4页
AIM: To study the role of connective tissue growth factor (CTGF) antibody in inhibiting bleb scarring after glaucoma filtration surgery (GFS) in rabbit model. METHODS: GFS was performed on both eyes in five rabbits. O... AIM: To study the role of connective tissue growth factor (CTGF) antibody in inhibiting bleb scarring after glaucoma filtration surgery (GFS) in rabbit model. METHODS: GFS was performed on both eyes in five rabbits. One eye of each rabbit was chosen randomly as antibody group and received subconjunctival injection of 0.1mL CTGF antibody (50mg/L) immediately after GFS applied and on the 5 th day after GFS. The other eye of each rabbit as control group was received subconjunctival injection of 0.1mL PBS at the same time as antibody group. On postoperative days 1, 3, 5, 7, 10, and 14, the appearance of filtrating blebs was observed under slit lamp, the area and the intraocular pressure (IOP) were measured with micrometer and applanation tonometer, respectively. RESULTS: On postoperative days 1, 3, 5, 7, 10, and 14, areas of filtrating blebs in antibody group were all larger comparing with the control group (P<0.05) and IOPs of antibody group were lower than the control group(P<0.05). CONCLUSION: Subconjunctival injection of CTGF antibody can maintain larger bleb area and lower IOP after GFS in rabbit. 展开更多
关键词 connective tissue growth factor antibody TRABECULECTOMY area of filtrating bleb intraocular pressure
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Evolution of real contact area during stick-slip movement observed by total reflection method 被引量:1
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作者 Zhijun Luo Baojiang Song +1 位作者 Jingyu Han Shaoze Yan 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第10期401-407,共7页
We build an experiment system based on total reflection(TR) method to observe the evolution of real contact area of polymethyl methacrylate(PMMA) in the continual stick-slip movement. The bilateral friction is adopted... We build an experiment system based on total reflection(TR) method to observe the evolution of real contact area of polymethyl methacrylate(PMMA) in the continual stick-slip movement. The bilateral friction is adopted to overcome the bending moment in the lateral friction movement. Besides some classical phenomena of stick-slip movement such as periodical slow increase of frictional force in sticking phase and a sudden drop when slipping, a special phenomenon that the contact area increases with the tangential force is observed, which was called junction growth by Tabor in 1959.Image processing methods are developed to observe the variation of the junction area. The results show that the center of the strongest contact region will keep sticking under the tangential force until the whole slipping, the strongest point undergoes three stages in one cycle, which are named as sticking stage, fretting stage, and cracking stage, respectively. The combined analysis reveals a physical process of stick-slip movement: the tangential force causes the increase of the real contact area, which reduces the pressure between the contact spots and finally leads to the slipping. Once slipping occurs,the real contact area drops to the original level resulting in the pressure increase to the original level, which makes the sticking happen again. 展开更多
关键词 total REFLECTION STICK-SLIP real contact area DETACHMENT JUNCTION growth
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Differential Growth and Development Response of Sunflower Hybrid in Contrasting Irrigation Regimes
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作者 Amjed Ali Ijaz Rasool Noorka 《American Journal of Plant Sciences》 2013年第5期1060-1065,共6页
Water is the most important factor limiting crop productivity at different growth stages of crop growth and development. The study was conducted to investigate the effect of irrigation scheduling on sunflower hybrid (... Water is the most important factor limiting crop productivity at different growth stages of crop growth and development. The study was conducted to investigate the effect of irrigation scheduling on sunflower hybrid (Hysun-38) at vegetative versus reproductive stages during spring season 2010. The trial was laid out in randomized complete block design (factorial arrangement), replicated thrice, having net plot size of 3.5 m × 9 m. The treatments comprised of irrigation application of 75 mm each, at different growth and development stages. viz., I1 = irrigation at plant establishment, I2 = irrigation at plant establishment and irrigation at vegetative phase, I3 = irrigation at plant establishment, irrigation at button stage and irrigation at flowering, and I4 = irrigation at plant establishment, irrigation at vegetative phase, irrigation at button stage and irrigation at achene’s formation. Days taken to 50% flowering was highest in I2, where irrigation was applied at plant establishment and vegetative phase, and in I4 treatment , where irrigation was given at seedling establishment, irrigation at vegetative phase, irrigation at button stage and irrigation at achene’s formation. Leaf area index at different growth intervals was significantly affected by irrigation levels. Crop growth rate was highest for treatment I4. Plant height (PH), stem girth (SG) head diameter (HD), 1000-achene’s weight (AW) and achene’s yield (AY) were significantly affected by different irrigation levels at various growth stages. Maximum AY (2415.68 kg·ha-1) was obtained in I4 treatment while, minimum AY (1275.35 kg·ha-1) was obtained in case of those plots which were irrigated only at plant establishment stage. Sunflower productivity was affected with irrigation regime at different growth stages with the strongest responses seen at early growth stages which ultimately affected the final achene yield adversely. 展开更多
关键词 growth IRRIGATION LEAF area INDEX YIELD
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Estimating Pinus palustris tree diameter and stem volume from tree height,crown area and stand-level parameters 被引量:15
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作者 C.A.Gonzalez-Benecke Salvador A.Gezan +3 位作者 Lisa J.Samuelson Wendell P.Cropper Daniel J.Leduc Timothy A.Martin 《Journal of Forestry Research》 SCIE CAS CSCD 2014年第1期43-52,共10页
Accurate and efficient estimation of forest growth and live biomass is a critical element in assessing potential responses to forest management and environmental change. The objective of this study was to develop mode... Accurate and efficient estimation of forest growth and live biomass is a critical element in assessing potential responses to forest management and environmental change. The objective of this study was to develop models to predict longleaf pine tree diameter at breast height (dbh) and merchantable stem volume (V) using data obtained from field measurements. We used longleaf pine tree data from 3,376 planted trees on 127 permanent plots located in the U.S. Gulf Coastal Plain region to fit equations to predict dbh and V as functions of tree height (H) and crown area (CA). Prediction of dbh as a function of H improved when CA was added as an additional independent variable. Similarly, predic- tions of V based on H improved when CA was included. Incorporation of additional stand variables such as age, site index, dominant height, and stand density were also evaluated but resulted in only small improvements in model performance. For model testing we used data from planted and naturally-regenerated trees located inside and outside the geographic area used for model fitting. Our results suggest that the models are a robust alternative for dbh and V estimations when H and CA are known on planted stands with potential for naturally-regenerated stands, across a wide range of ages. We discuss the importance of these models for use with metrics derived from remote sensing data. 展开更多
关键词 Longleaf pine diameter-height relationships crown area individual-tree stem volume growth and yield modeling
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GEOFEATURES AND RESOURCE ELEMENT COMBINATION OF TUMEN RIVER ECONOMIC GROWTH TRIANGLE
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作者 Yuan Shuren Northeast Normal University, Changchun, 130024, P.R.ChinaXu Shumei Harbin Teachers Uriversity, Harbin 150080, P.R.ChinaDuan Jixian East\|West Center, Hawaii, USA 《Journal of Geographical Sciences》 SCIE CSCD 1997年第1期53-62,共10页
The development of world economy has been heading for globalization and regionalization. In recent years, this tendency has born great impact on the rapid economic development of the Asian and Pacific countries, which... The development of world economy has been heading for globalization and regionalization. In recent years, this tendency has born great impact on the rapid economic development of the Asian and Pacific countries, which assumes the form of economic growth triangle as their major way for regional cooperation involving multiple nations. Among these, the Tumen River Triangle consisting of six countries' cooperation may have attracted great attention. Since 1991 when UNDP began to draw up plans for such a mammoth project which is called the Tumen River Area Development Project (or TRADP), the international economic cooperation in this area has been developing energetically. It is now necessary to assess the characteristics of geographical conditions and various economic resources from the viewpoints of economic geography and expound the mammoth benefits both in economy and to society. The demonstration would undoubtedly absorb more international capital to this area and enhance its economic and social development. 展开更多
关键词 Tumen River area economic growth triangle geofeatures resource element combination.
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喀斯特地区土地流转如何促进农户增收?——基于8省3678户的经验证据 被引量:1
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作者 伍国勇 张洲羽 +1 位作者 闵文斌 卢凤雏 《资源开发与市场》 CAS 2024年第7期979-987,共9页
充分发挥喀斯特地区土地流转的农户增收效应是推进山地农业高质量发展的有效渠道。基于中国喀斯特地区8个省区市3 678户农户微观调研数据,采用有序Logit模型、倾向得分匹配法、KHB方法等,考察土地流转对农户收入的影响和作用机制。结果... 充分发挥喀斯特地区土地流转的农户增收效应是推进山地农业高质量发展的有效渠道。基于中国喀斯特地区8个省区市3 678户农户微观调研数据,采用有序Logit模型、倾向得分匹配法、KHB方法等,考察土地流转对农户收入的影响和作用机制。结果表明:(1)土地流转显著提升了喀斯特地区农户家庭总收入水平,土地流转户收入水平较未参与流转户约高出12.86%;(2)相比于土地转入户,土地转出对农户收入增长的影响更为显著;(3)外出务工和家庭创业在土地转出影响农户收入关系中起中介作用,解释比例分别为17.18%和4.63%;农业机械化在耕地较为平整的转入户对收入的影响中起中介作用,解释比例为16.93%;(4)土地流转对种植经济作物、耕地较为平整、灌溉条件较好的农户家庭总收入影响显著为正。为此,建议进一步健全喀斯特地区土地流转机制,促进非农产业发展,加强丘陵山区农业机械化和农田水利设施建设,发展喀斯特地区特色高效农业,鼓励更多农户积极参与土地流转。 展开更多
关键词 农户 土地流转 收入增长 中介效应 喀斯特地区
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Comparisons of Yield and Growth Behaviors of Hybrid Rice Under Different Nitrogen Management Methods in Tropical and Subtropical Environments 被引量:13
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作者 Ibrahim Md PENG Shao-bing +3 位作者 TANG Qi-yuan HUANG Min JIANG Peng ZOU Ying-bin 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2013年第4期621-629,共9页
To compare the grain yield and growth behaviors of hybrid rice, field experiments were conducted in a subtropical environment in Changsha, Hunan Province, China, and in two tropical environments in Gazipur and Habigan... To compare the grain yield and growth behaviors of hybrid rice, field experiments were conducted in a subtropical environment in Changsha, Hunan Province, China, and in two tropical environments in Gazipur and Habiganj in Bangladesh during 2009 to 2011. Three hybrid rice cultivars were grown under three nitrogen (N) management treatments in each experiment. The results showed that grain yield was significantly affected by locations, N treatments and their interaction but not by cultivars. Changsha produced 8-58% higher grain yields than Bangladesh locations. Sink size (spikelet number per unit land area) was responsible for these yield differences. Larger panicle size (spikelet number per panicle) contributed to greater sink size in Changsha. Aboveground total biomass was greater in Changsha than in Bangladesh locations, whereas harvest index was higher in Bangladesh locations than in Changsha. Crop growth rate (CGR) was greater at Changsha than Bangladesh locations during vegetative phase, while the difference was relatively small and not consistent during the later growth phases. Higher leaf area index and leaf area duration were partly responsible for the greater CGR in Changsha. Real-time N management (RTNM) produced lower grain yields than fixed-time N management in more than half of the experiments. Our study suggested that further improvement in rice yield in the tropical environments similar to those of Bangladesh will depend mainly on the ability to increase panicle size as well as CGR during vegetative phase, and the chlorophyll meter threshold value used in RTNM needs to be modified according to environmental conditions and cultivar characteristics to achieve a desirable grain yield. 展开更多
关键词 crop growth rate biomass production hybrid rice leaf area duration leaf area index real-time nitrogenmanagement
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大都市成长区公共服务设施的配置优化策略——以广州开发区为例
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作者 张擎 《规划师》 CSSCI 北大核心 2024年第10期113-120,共8页
分析大都市成长区公共服务设施配置的特征与存在问题,深入挖掘影响大都市成长区公共服务设施合理配置的因素,全面梳理公共服务设施供需关系的转变趋势,基于此提出大都市成长区公共服务设施的配置优化策略,并以广州开发区为例展开实证分... 分析大都市成长区公共服务设施配置的特征与存在问题,深入挖掘影响大都市成长区公共服务设施合理配置的因素,全面梳理公共服务设施供需关系的转变趋势,基于此提出大都市成长区公共服务设施的配置优化策略,并以广州开发区为例展开实证分析,以期为同类地区提供借鉴。 展开更多
关键词 大都市成长区 公共服务设施配置策略 广州开发区
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