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Search Results: 1 - 10 of 188335 matches for " WANG Jin-da "
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Spatial distribution of Cd, Pb, as contents in the farmland black soil in Jilin Province

Cao Hui-cong,Wang Jin-da,Zhang Xue-lin,
Cao HC
,Wang JD,Zhang XL

环境科学 , 2006,
Abstract: Spatial distribution and pattern of Cadmium(Cd),Lead(Pb) and Arsenic(As) contents in the farmland black soil in Jilin Province were analyzed using geostatistics methods.Result of semivariance fitness models showed that Pb content in soil was auto-correlated to a moderate degree while contents of Cd and As were autocorrelated to a low degree,respectively.Based on the results of semivariance analyses,distribution maps were generated using Kriging interpolation.The result showed that heavily Cd-contaminated site occurred mainly around the mine area, and the accumulation area for Pb appeared mostly in the suburb and roadsides,while in farmland of suburb and vicinity of coal mine the As content was higher.
Seasonal changes of soil phosphorus fractions under Calamagrostis angustifolia wetlands in Sanjiang Plain, China

QIN Sheng-Jin,LIU Jing-Shuang,WANG Guo-Ping,WANG Jin-Da,

生态学报 , 2007,
Abstract: The seasonal dynamics of soil P fractions was determined in the Sanjiang plain marshes.The soil samples were taken from a depression marsh once or twice every month during the growth season and soil P fractions were determined by the modified Hedley fraction method in 2005.The study showed that P was mainly organically bound in the Sanjiang Plain wetlands.NaOH extractable organic P(NaOH-Po)and inorganic P(NaOH-Pi)was the predominant form in total organic P(TPo)and total inorganic P(TPi);respectively.The content of Resin-P was highest at end of August and lowest at the early days of July,seasonal dynamic of NaHCO3-Pi and NaOH-Pi were similar to Resin-P.Dil.HCl-Pi and Conc.HCl-Pi had their highest and lowest value at the beginning of September and the initial stage of May.The variation coefficient of Resin-P and Conc.HCl-Pi were higher than other Pi fractions,the level of them decreased from the beginning of growth season to the end of growth season,while the other Pi fractions increased in some degree.For organic phosphorus(Po),the variation coefficient of NaOH-Po was highest in the Po fractions,and NaOH-Po content reduced in the end of the growth season,NaHCO3-Po,Conc.HCl-Po and Residual-P had no obvious changes during this time.The concentration of TP and TPo had significant correlation and the concentration of TP was similar to TPo.The dynamic of P fractions,especially inorganic P forms are intensively affected by the plants,the change of their value go with the absorbing intensity of plants,especially Resin-P.The transformation of phosphorus is directly promoted and also indirectly improved by environmental factors(e.g.water and temperature)with their effect on the biomass or activity of microorganism.The soil water content plays an important role in sorption and desorption of NaHCO3-Pi,NaOH-Pi from soil.The biomass or activity of microorganism usually influences mineralization of organic P.The Pi which is released from mineralization of Po is usually first absorbed by mineral oxide and then transform into other more active form for utilizing of plants or microbe.
Study on the Relation of Plant Biomass and CH4, N2O Emission in the Wetland of Sanjiang Plain

ZHOU Wang-Ming,WANG Jin-Da,LIU Jing-Shuang,

中国科学院研究生院学报 , 2006,
Abstract: In this study,we explored relationships between plant biomass and emission of greenhouse-gases.The biomass of different plant communities(Deyeuxia angustifolia,Carex lasiocarpa and Carex pseudocuraic) and emission of CH_4,N_2O were studied in the typical freshwater wetland in Sanjiang Plain from June to September,2003.The result suggests that the season variations of the aboveground biomass can be described by parabola model Y=a bT cT~2.The emission of CH_4 showed strong difference in the plant zones and the trend is reduction from center to brim in the Sanjiang Wetland.The emission of N_2O of communities expresses the trend of "up-down-up".But the first time of the top emission is earlier in the Deyeuxia angustifolia than Carex lasiocarpa and Carex pseudocuraic distinctly.Analyses show that the biomass of different plant community has the strong linear relation with the cumulated emission of CH_4,N_2O before the plant reaches its largest aboveground biomass during growing seasons.And it can be described by function Y=aX b,and their R~2 were almost over 0.89.
Evolution of ecological carrying capacity of western Jilin Province via set pair analysis and principal component analysis

WANG Ming-Quan,WANG Jin-Da,LIU Jing-Shuang,

中国生态农业学报 , 2009,
Abstract: The evolution of ecological carrying capacity (ECC) of western Jilin Province (1995 ~ 2004) was analyzed via set pair analysis (SPA) and principal component analysis (PCA). From PCA, 3 principal components influencing ECC were identified, which were then used to construct ECC assessment framework. The approach degree of optimal scenario aggregate was determined via SPA, which was then used to evaluate the quality of ECC evolution. The results indicate that ECC of western Jilin Province has an increasing tendency, and the approach degree varies from 0.430 0 to 0.501 2, with obvious fluctuations. Improvements in economic efficiency contribute the most to ECC increase, while water resources constitute the main driving factor of ECC fluctuation, and the main factor limiting ECC of western Jilin Province. Compared to 1995, western Jilin Province supports more people with higher economic and living standards in 2004, though at the cost of high resource utilization and severe ecosystem degradation. Thus the approach degree of resource-environment has steadily declined since 1995. The vulnerability of the resource-environment system would severely limit future ECC of western Jilin Province unless effective countermeasures are adopted.
Evolution study on the ecological carrying capacity of West Jilin province based on the principal component analysis and entropy weight method

WANG Ming-Quan,WANG Jin-Da,LIU Jing-Shuang,

中国科学院研究生院学报 , 2008,
Abstract: West Jilin province is a typical area of the frangible agro-pastoral ecotone in northern China, where the sustainable development was heavily restricted by both the natural and socio-economic factors. Principal Component Analysis (PCA) and Entropy methods were used to evaluate the evolution of the ecological carrying capacity (ECC) of West Jilin province from 1995-2004. Through PCA, 3 principal components were obtained from all the indicators to represent 3 main factors of ECC: C1 Development level of ecosystem, C2 Economic efficiency and C3 Water resource abundant. Entropy method was utilized to calculate the weight of each component and corresponding indicators and then got the comprehensive index ECC. The results indicated that: ECC of West Jilin province has been increasing with obvious fluctuation in the past 10 years, and the economic efficiency rise contributed most to the ECC increase while the water resource was the main driving force of ECC fluctuation. As a consequence, the ECC increase led more resource requirement and sever ecosystem degradation of West Jilin province, thus the resource-environment developed slowly from 1995-2004. The resource-environment, especially the water resource, will lead great restriction to the ECC in future if no effective countermeasures to improve it.
Effects of added concentrations of Cd and Pb on the distribution of Cd and Pb forms in black soil of northeast China and on the Cd and Pb uptake by cole

CAO Hui-cong,WANG Jin-da,ZHANG Xue-lin,

生态学杂志 , 2007,
Abstract: With pot culture and sequential extraction,this paper studied the effects of different added concentrations of cadmium(Cd) and lead(Pb) on the distribution of Cd and Pb forms in black soil and on the Cd and Pb uptake by cole plant.The results showed that with the increasing concentration of added Cd and Pb,there was a remarkable increase in the contents of exchangeable Cd and carbonate-and Fe-Mn oxide-bound Pb in soil.The exogenous Cd in soil was mainly existed in residual and exchangeable forms,while Pb was mainly in residual form but relatively low in exchangeable form.Lower concentration of added Cd and Pb had positive effects on cole growth,while their higher concentration inhibited the growth significantly.The concentrations of Cd and Pb were greater in root than in shoot,and less Pb was transferred to shoot,compared with Cd.The contents of all forms Cd and Pb in soil were positively correlated with those in cole shoot and root,but negatively correlated with cole dry mass.Among all the chemical forms of Cd and Pb,exchangeable form played an important role in the decrease of cole dry mass,and carbonate-bound form contributed most to the absorption of Cd and Pb by cole.
Evaluation of eco-environmental frangibility in West Jilin Province based on matter-element model

WANG Ming-quan,WANG Jin-da,LIU Jing-shuang,DOU Jing-xin,

生态学杂志 , 2007,
Abstract: 从水资源条件、自然灾害和土地“三化”(沙漠化、盐碱化和草原退化)3方面出发,选取10项能反映吉林西部生态环境脆弱性而彼此之间相互独立的指标建立物元模型,采用物元模型和熵权法对吉林西部各县市生态环境进行了脆弱性评价。结果表明1985—2000年吉林省西部乾安县、扶余县、长岭县整体生态环境脆弱性相对较轻为Ⅰ级;大安市、前郭县生态环境脆弱性为中等Ⅱ级;脆弱性较重的地区有洮北区、镇赉县、洮南市、通榆县,脆弱等级为Ⅲ级。整体而言,吉林西部松原市各县环境脆弱性要好于白城市各县市。各县市对不同因子的敏感程度也各不相同,水资源条件脆弱性较重的地区为大安、通榆;自然灾害较为严重的地区为洮北、镇赉、洮南、通榆、乾安;土地“三化”现象幅度最大的地区为洮北、洮南、前郭。
Dynamic coupling of ecological supporting capability and socioeconomic development of west Jilin Province.

WANG Ming-quan,WANG Jin-da,LIU Jing-shuang,GU Kang-kang,

应用生态学报 , 2009,
Abstract: 利用协调发展模型和剪刀差方法,对1986—2004年间吉林省西部生态支撑能力[F(x)]和社会经济[F(y)]的耦合关系进行了分析.结果表明:研究期间,吉林省西部F(x)呈先下降后略有上升的趋势,而F(y)总体呈指数形式增长;受自然和人为因素影响,F(x)和F(y)具有明显的脆弱性;F(x)和F(y)的剪刀差α从1986年的4.93°下降到1996年的0.28°,后又上升至2004年的12.30°;1995—2004年间,吉林省西部由以损害F(x)促进F(y)发展的状态正逐渐向两者协调发展状态过渡,F(x)和F(y)的耦合协调度由轻度或濒临失调衰退类型转变为勉强或初级协调类型,但这种刚发展起来的初级协调状态仍存在较大的不稳定性;1995年后,α增长较快且协调度C波动强烈F(x)和F(y)冲突较强烈,研究区处于生态环境问题的多发期;相比单一的协调发展模型,与剪刀差方法结合可从发展状态和演变速率2个角度来表征F(x)和F(y)的相互作用,它既能反映两者发展的均衡程度又能反映两者的冲突强度,可更加全面和深入地探讨生态支撑能力和社会经济发展的耦合关系.
A simulation study of a dual-plate in-room PET system for dose verification in carbon ion therapy
Ze Chen,Zheng-Guo Hu,Guo-Qing Xiao,Jin-Da Chen,Xiu-Ling Zhang,Zhong-Yan Guo,Zhi-Yu Sun,Wen-Xue Huang,Jian-Song Wang
Physics , 2013, DOI: 10.1088/1674-1137/38/8/088202
Abstract: Carbon ion therapy have the ability to overcome the limitation of convertional radiotherapy due to its most energy deposition in selective depth, usually called Bragg peak, which results in increased biological effectiness. During carbon ion therapy, lots positron emitters such as $^{11}$C, $^{15}$O, $^{10}$C are generated in irradiated tissues by nuclear reactions. Immediately after patient irradiation, PET scanners can be used to measure the spatial distribution of positron emitters, which can track the carbon beam to the tissue. In this study, we designed and evaluated an dual-plate in-room PET scanner to monitor patient dose in carbon ion therapy, which is based on GATE simulation platform. A dual-plate PET is designed to avoid interference with the carbon beam line and with patient positioning. Its performance was compared with that of four-head and full-ring PET scanners. The dual-plate, four-head and full-ring PET scanners consisted of 30, 60, 60 detector modules, respectively, with a 36 cm distance between directly opposite detector modules for dose deposition measurements. Each detector module was consisted of a 24$\times$24 array of 2$\times2\times$18 mm$^{3}$ LYSO pixels coupled to a Hamamatsu H8500 PMT. To esitmate the production yield of positron emitters, a 10$\times15\times$15 cm$^{3}$ cuboid PMMA phantom was irradiated with 172, 200, 250 AMeV $^{12}$C beams. 3D images of the activity distribution of the three type scanners are produced by an iterative reconstruction algorithm. By comparing the longitudinal profile of positron emitters, measured along the carbon beam path, we concluded that the development of a dual-plate PET scanner is feasible to monitor the dose distribution for carbon ion therapy.
Optimum performance investigation of LYSO crystal pixels: A comparison between GATE simulation and experimental data
Ze Chen,Zheng-Guo Hu,Jin-Da Chen,Xiu-Ling Zhang,Zhi-Yu Sun,Wen-Xue Huang,Jian-Song Wang,Zhong-Yan Guo,Guo-Qing Xiao
Physics , 2013,
Abstract: Monte Carlo simulation plays an important role in the study of time of flight (TOF) positron emission tomography (PET) prototype. As it can incorporate accurate physical modeling of scintillation detection process, from scintillation light generation, the transport of scintillation photos through the crystal(s), to the conversion of these photons into electronic signals. The Geant4 based simulation software GATE can provide a user-friendly simulation platform containing the properties needed. In this work, we developed a dedicated module in GATE simulation tool. Using this module, we simulated the light yield, energy resolution, time resolution of LYSO pixels with the same cross-section ($4\times4 mm^{2}$) of different lengths: 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, coupled to a PMT. The experiments were performed to validate the GATE simulation results. The results indicate that the best time resolution (484.0$\pm$67.5 ps) and energy resolution (13.3$\pm$0.4 %) could be produced by using pixel with length of 5 mm. The module can also be applied to other cases for precisely simulating optical photons propagating in scintillators.
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