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粘重地果园行内起垅覆草栽培技术试验
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作者 马玉敏 孙海伟 +1 位作者 刘志荣 侯立群 《山东林业科技》 2001年第1期19-20,共2页
通过果园行内起垅覆草 ,加厚了根区的有效活土层 ,提高了保水和排水能力 ,改善了果树根系的生活环境 ,土壤容重降低 9 7% ,空隙度提高 4 2 5% ,0~ 4 0cm土层内总根数增加 2 89条 ;促进树体地上部的生长发育 ,新梢长增加 16 8% ;
关键词 果园 行内地卢垅覆草 重地
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话说固原金糜子
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作者 陆叔文 《农村百事通》 2025年第8期52-52,共1页
固原市处在中原农耕文化和北方游牧文化的交汇处,是历史上的西北经济重地、交通枢纽和军事要地,也是宁夏五个地级市中唯一一个不沿黄河的城市。目前,在固原市唯一一家百年企业是用糜子酿酒的白酒企业。该企业生产的金糜子酒有着“风来... 固原市处在中原农耕文化和北方游牧文化的交汇处,是历史上的西北经济重地、交通枢纽和军事要地,也是宁夏五个地级市中唯一一个不沿黄河的城市。目前,在固原市唯一一家百年企业是用糜子酿酒的白酒企业。该企业生产的金糜子酒有着“风来隔壁三家醉,雨过开瓶十里香”的美誉。 展开更多
关键词 游牧文化 白酒 金糜子 农耕文化 经济重地 固原
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近代中国农业现代化滞后原因初探 被引量:4
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作者 杨桂宏 王伟 《中国农业大学学报(社会科学版)》 2002年第2期17-21,共5页
在近现代经济结构的现代化转型过程中 ,农业较之工业显得缓慢和滞后。这其中固然有中国固有的农业基础薄弱、战争破坏以及世界经济危机等多种因素的影响 ,但本文力求抛开这些表面上的因素 ,试从政府决策、市场结构、农业传统文化这三方... 在近现代经济结构的现代化转型过程中 ,农业较之工业显得缓慢和滞后。这其中固然有中国固有的农业基础薄弱、战争破坏以及世界经济危机等多种因素的影响 ,但本文力求抛开这些表面上的因素 ,试从政府决策、市场结构、农业传统文化这三方面对近代中国农业现代化滞后原因加以探求。 展开更多
关键词 农业现代化 双重剪刀差 市场多环节 重地思想
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AP_(950)血浆蛋白粉对断奶仔猪生长表现的影响 被引量:1
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作者 王家圣 潘晚平 +3 位作者 赵自力 申祥科 李波 石俊宏 《养猪》 北大核心 2000年第4期18-18,共1页
关键词 断奶仔猪 AP50血浆蛋白粉 日增重 重地
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Joint inversion of gravity and multiple components of tensor gravity data 被引量:3
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作者 鲁光银 曹书锦 朱自强 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第7期1767-1777,共11页
Geological structures often exhibit smooth characteristics away from sharp discontinuities. One aim of geophysical inversion is to recover information about the smooth structures as well as about the sharp discontinui... Geological structures often exhibit smooth characteristics away from sharp discontinuities. One aim of geophysical inversion is to recover information about the smooth structures as well as about the sharp discontinuities. Because no specific operator can provide a perfect sparse representation of complicated geological models, hyper-parameter regularization inversion based on the iterative split Bregman method was used to recover the features of both smooth and sharp geological structures. A novel preconditioned matrix was proposed, which counteracted the natural decay of the sensitivity matrix and its inverse matrix was calculated easily. Application of the algorithm to synthetic data produces density models that are good representations of the designed models. The results show that the algorithm proposed is feasible and effective. 展开更多
关键词 hyper-parameter regularization full gravity gradient tensor preconditioned matrix Occam's inversion focusinginversion
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Mineralization-related geochemical anomalies derived from stream sediment geochemical data using multifractal analysis in Pangxidong area of Qinzhou-Hangzhou tectonic joint belt, Guangdong Province, China 被引量:5
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作者 张焱 周永章 +8 位作者 王林峰 王正海 何俊国 安燕飞 李红中 曾长育 梁锦 吕文超 高乐 《Journal of Central South University》 SCIE EI CAS 2013年第1期184-192,共9页
Distinguishing geochemical anomalies from background is a basic task in exploratory geochemistry. The derivation of geochemical anomalies from stream sediment geochemical data and the decomposition of these anomalies ... Distinguishing geochemical anomalies from background is a basic task in exploratory geochemistry. The derivation of geochemical anomalies from stream sediment geochemical data and the decomposition of these anomalies into their component patterns were described. A set of stream sediment geochemical data was obtained for 1 880 km 2 of the Pangxidong area, which is in the southern part of the recently recognized Qinzhou-Hangzhou joint tectonic belt. This belt crosses southern China and tends to the northwest (NE) direction. The total number of collected samples was 7 236, and the concentrations of Ag, Au, Cu, As, Pb and Zn were measured for each sample. The spatial combination distribution law of geochemical elements and principal component analysis (PCA) were used to construct combination models for the identification of combinations of geochemical anomalies. Spectrum-area (S-A) fractal modeling was used to strengthen weak anomalies and separate them from the background. Composite anomaly modeling was combined with fractal filtering techniques to process and analyze the geochemical data. The raster maps of Au, Ag, Cu, As, Pb and Zn were obtained by the multifractal inverse distance weighted (MIDW) method. PCA was used to combine the Au, Ag, Cu, As, Pb, and Zn concentration values. The S-A fractal method was used to decompose the first component pattern achieved by the PCA. The results show that combination anomalies from a combination of variables coincide with the known mineralization of the study area. Although the combination anomalies cannot reflect local anomalies closely enough, high-anomaly areas indicate good sites for further exploration for unknown deposits. On this basis, anomaly and background separation from combination anomalies using fractal filtering techniques can provide guidance for later work. 展开更多
关键词 geochemical anomalies fractal modeling principal component analysis Qinzhou-Hangzhou joint tectonic belt streamsediments
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Soil heavy metal(loid)s and risk assessment in vicinity of a coal mining area from southwest Guizhou, China 被引量:17
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作者 QIN Fan-xin WEI Chao-fu +3 位作者 ZHONG Shou-qin HUANG Xian-fei PANG Wen-pin JIANG Xin 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第9期2205-2213,共9页
Total concentrations of arsenic, lead, cadmium, mercury, nickel, chromium, and copper in the soils from near a coal mine area in southwest Guizhou, China, were measured to evaluate the level of contamination, and the ... Total concentrations of arsenic, lead, cadmium, mercury, nickel, chromium, and copper in the soils from near a coal mine area in southwest Guizhou, China, were measured to evaluate the level of contamination, and the potential ecological risks posed by the heavy metals were quantitatively estimated. Results reveal that all heavy metals/metalloid exceeded the background values for soil environmental quality of heavy metals in Guizhou area. Geo-accumulation index(I_(geo)) showed that arsenic had the highest contamination level(I_(geo)=4) among the seven heavy metals/metalloid, and the contamination levels of mercury and lead were also relatively high(I_(geo)=3). Pearson correlation and cluster analysis identified that mercury, copper and arsenic had a relationship, and their presence might be mainly related to mining activity, coal and oil combustion, and vehicle emissions. Improved Nemerow index indicated that the overall level of heavy metal contamination in the studied area ranged from moderately–heavily contaminated to heavily contaminated level. Potential ecological risk index(R_I) analysis manifested that the whole ecological risk level ranged from high degree to very high degree(325.30≤R_I≤801.02) in the studied soil samples, and the potential ecological risk factors (E_r^i) of heavy metals/metalloid were as follows: Hg > As > Cd > Pb > Cu > Ni > Cr, and the E_r^i of Hg and As reached very high risk grade. 展开更多
关键词 heavy metals soil contamination ecological risk coal mining area Xingren county
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Dynamic effect of heavy-haul train on seismic response of railway cable-stayed bridge 被引量:7
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作者 ZHU Zhi-hui GONG Wei +3 位作者 WANG Kun LIU Yu DAVIDSON Michael T JIANG Li-zhong 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第7期1939-1955,共17页
This paper focuses on understanding and evaluating the dynamic effect of the heavy-haul train system on the seismic performance of a long-span railway bridge. A systematic study on the effect of heavy-haul trains on b... This paper focuses on understanding and evaluating the dynamic effect of the heavy-haul train system on the seismic performance of a long-span railway bridge. A systematic study on the effect of heavy-haul trains on bridge seismic response has been conducted, considering the influence of vehicle modeling strategies and dynamic characteristics of the seismic waves. For this purpose, the performance of a long-span cable-stayed railway bridge is assessed with stationary trains atop it, where the heavy-haul vehicles are modeled in two different ways: the multi-rigid body model with suspension system and additional mass model. Comparison of the bridge response in the presence or absence of the train system has been conducted, and the vehicle loading situation, which includes full-load and no-load, is also discussed. The result shows that during the earthquake, the peak moment of the main girder and peak stress of stay cables increase by 80% and by 40% in the presence of fully loaded heavy-haul trains, respectively. At the same time, a considerable decrease appears in the peak acceleration of the main girder. This proves the existence of the damping effect of the heavy-haul train system, and this effect is more obvious for the fully loaded vehicles. Finally, this paper proposes an efficient vehicle modeling method with 2 degrees of freedom(DOF) for simplifying the treatment of the train system in bridge seismic checking. 展开更多
关键词 train-bridge interaction heavy-haul train cable-stayed bridge EARTHQUAKE live load
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Changes of hydrochemical composition and heavy metals concentration in shallow groundwater from karst hilly areas in Guiyang region,China 被引量:2
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作者 刘方 刘丛强 +1 位作者 赵杨 李准 《Journal of Central South University》 SCIE EI CAS 2010年第6期1216-1222,共7页
The quality changes of shallow groundwater from karst hilly areas in Guiyang region of China impacted by the urbanization were investigated. The results show that the major ions in shallow groundwater from the karst h... The quality changes of shallow groundwater from karst hilly areas in Guiyang region of China impacted by the urbanization were investigated. The results show that the major ions in shallow groundwater from the karst hilly areas are mainly composed of HCO3^-, SO4^2-, Ca^2+ and Mg^2+, and the concentrations scopes of NO3^-, Cl^-, K^+ and Na^+ of the groundwater in agricultural, residential and industrial areas are 4.5-9.6, 2.8-7.1, 3.9-6.3 and 2.5-4.9 times higher than those in the forest areas, respectively. The concentrations of As, Pb and Cd of shallow groundwater in the industrial areas are also significantly enhanced, followed by those in the residential areas and the agricultural areas. The concentrations of NO3^-, SO4^2- , As, Pb and Cd of the groundwater in the industrial areas and those of NO3^- , SO4^2-, As and Cd of shallow groundwater in the residential areas reach grade Ⅲ of the Groundwater Quality Standard of China (GB/T 14848-93), while the concentration of NO3^- in the groundwater from the industrial areas exceeds grade V. With the process of urbanization, NO3^- is the key factor to influence the groundwater quality in karst hilly areas, followed by SO4^2-, As, Pb and Cd. 展开更多
关键词 karst hilly areas shallow groundwater URBANIZATION heavy metals Guiyang
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GOCE kinematic orbit adjustment for EGM validation and accelerometer calibration
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作者 徐天河 孙张振 +2 位作者 江楠 陈康康 李敏 《Journal of Central South University》 SCIE EI CAS 2014年第6期2397-2403,共7页
The main principle and mathematical model of GOCE kinematic orbit adjustment for Earth gravity field model (EGM) validation and accelerometer calibration are presented. Based on 60 days GOCE kinematic orbits with 1-... The main principle and mathematical model of GOCE kinematic orbit adjustment for Earth gravity field model (EGM) validation and accelerometer calibration are presented. Based on 60 days GOCE kinematic orbits with 1-2 cm accuracy and accelerometer data from 2009-11-02 to 2009-12-31, the RMS-of-fit (ROF) of them using EGM2008, EIGEN-SC, ITG- GRACE2010S and GOCO01S up to 120, 150 and 180 degree and order (d/o) are evaluated and compared. The scale factors and biases of GOCE accelerometer data are calibrated and the energy balance method (EBM) is performed to test the accuracy of accelerometer calibration. The results show that GOCE orbits are also sensitive to EGM from 120 to 150 d/o. The ROFs of EGMs with 150 and 180 d/o are obviously better than those of EGMs with 120 d/o. The ROFs of GOCO01S and ITG-GRACE2010S are almost the same up to 120 and 150 d/o, which are about 3.3 cm and 1.8 cm, respectively. They are far better than those of EGM2008 and EIGEN-SC with the same d/o. The ROF of GOCO01S with 180 d/o is about 1.6 em, which is the best one among those EGMs. The accelerometer calibration accuracies (ACAs) of ITG-GRACE2010S and GOCO01S are obviously higher that those of EGM2008 and EIGEN-SC. The ACA of GOCO01S with 180 d/o is far higher than that of EGMs with 120 d/o, and a little higher than that of ITG-GRACE2010S with 150 d/o. I t is suggested that the newest released EGM such as GOCO01S or GOCO02S till at least 150 d/o should be chosen in GOCE precise orbit determination (POD) and accelerometer calibration. 展开更多
关键词 GOCE orbit adjustment Earth gravity field model kinematic orbit accelerometer calibration
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Dynamic response law about gravity retaining wall to seismic characteristics and earth fill properties 被引量:1
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作者 林于廉 刘涌江 李家杰 《Journal of Central South University》 SCIE EI CAS 2012年第3期657-663,共7页
In order to find the dynamic response laws of retaining walls affected by certain earthquake loads,the influence of the seismic wave characteristics and sub-grade fill parameters(including the foundation surface slope... In order to find the dynamic response laws of retaining walls affected by certain earthquake loads,the influence of the seismic wave characteristics and sub-grade fill parameters(including the foundation surface slope) were focused on,and a series of tests were performed.The results show that the maximum stress of the retaining wall decreases as internal friction angle,foundation slope,filled soil cohesion and the biggest dynamic elastic modulus increase,while it increases with the seismic frequency and seismic input peak dropping.The addition value of dynamics earth pressure increases when seismic frequency and seismic input peak are reduced,while it decreases when the filled soil cohesion and internal friction angle rise.Meanwhile,dynamic elastic modulus and foundation slope have no obvious influences on addition value of dynamics earth pressure.The slope will be instable if the seismic input peak exceeds 0.5g and be disruptive if seismic frequency is larger than 2.5 Hz.The mid-lower parts of retaining walls are in most heavy and obvious response to these factors,which reveals the mechanism of "belly burst" in retaining wall that appears commonly in practical projects. 展开更多
关键词 retaining wall earthquake characteristics earth fill dynamic response
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Passive seismic velocity tomography on longwall mining panel based on simultaneous iterative reconstructive technique (SIRT) 被引量:14
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作者 N.Hosseini K.Oraee +1 位作者 K.Shahriar K.Goshtasbi 《Journal of Central South University》 SCIE EI CAS 2012年第8期2297-2306,共10页
Mining operation, especially underground coal mining, always has the remarkable risks of ground control. Passive seismic velocity tomography based on simultaneous iterative reconstructive technique (SIRT) inversion ... Mining operation, especially underground coal mining, always has the remarkable risks of ground control. Passive seismic velocity tomography based on simultaneous iterative reconstructive technique (SIRT) inversion is used to deduce the stress redistribution around the longwall mining panel. The mining-induced microseismic events were recorded by mounting an array of receivers on the surface, above the active panel. After processing and filtering the seismic data, the three-dimensional tomography images of the p-wave velocity variations by SIRT passive seismic velocity tomography were provided. To display the velocity changes on coal seam level and subsequently to infer the stress redistribution, these three-dimensional tomograms into the coal seam level were sliced. In addition, the boundary element method (BEM) was used to simulate the stress redistribution. The results show that the inferred stresses from the passive seismic tomograms are conformed to numerical models and theoretical concept of the stress redistribution around the longwall panel. In velocity tomograms, the main zones of the stress redistribution arotmd the panel, including front and side abutment pressures, and gob stress are obvious and also the movement of stress zones along the face advancement is evident. Moreover, the effect of the advance rate of the face on the stress redistribution is demonstrated in tomography images. The research result proves that the SIRT passive seismic velocity tomography has an ultimate potential for monitoring the changes of stress redistribution around the longwall mining panel continuously and subsequently to improve safety of mining operations. 展开更多
关键词 longwall mining passive seismic velocity tomography simultaneous iterative reconstructive technique (SIRT) boundary element method stress redistribution ground control
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Role of street patterns in zone-based traffic safety analysis 被引量:6
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作者 郭强 裴欣 +1 位作者 姚丹亚 黄仕进 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第6期2416-2422,共7页
Although extensive analyses of road segments and intersections located in urban road networks have examined the role of many factors that contribute to the frequency and severity of crashes, the explicit relationship ... Although extensive analyses of road segments and intersections located in urban road networks have examined the role of many factors that contribute to the frequency and severity of crashes, the explicit relationship between street pattern characteristics and traffic safety remains underexplored. Based on a zone-based Hong Kong database, the Space Syntax was used to quantify the topological characteristics of street patterns and investigate the role of street patterns and zone-related factors in zone-based traffic safety analysis. A joint probability model was adopted to analyze crash frequency and severity in an integrated modeling framework and the maximum likelihood estimation method was used to estimate the parameters. In addition to the characteristics of street patterns, speed, road geometry, land-use patterns, and temporal factors were considered. The vehicle hours was also included as an exposure proxy in the model to make crash frequency predictions. The results indicate that the joint probability model can reveal the relationship between zone-based traffic safety and various other factors, and that street pattern characteristics play an important role in crash frequency prediction. 展开更多
关键词 street pattern Space Syntax joint probability model crash frequency crash severity
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Diesel oil infiltration in soils with selected antecedent water content and bulk density
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作者 马艳飞 李永霞 +3 位作者 S.H.Anderson 郑西来 冯雪冬 高佩玲 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第8期1924-1930,共7页
The effects of soil texture, initial water content and bulk density on diesel oil infiltration in fine sand and silty clay loam materials were evaluated. Three physical and two empirical equations express diesel oil i... The effects of soil texture, initial water content and bulk density on diesel oil infiltration in fine sand and silty clay loam materials were evaluated. Three physical and two empirical equations express diesel oil infiltration through soils with time, with coefficients of determination greater than 0.99. Diesel oil infiltrates more quickly in the fine sand than in the silty clay loam material. Diesel oil infiltration rates are found to decrease with increasing initial water content and bulk density for the silty clay loam material. The infiltration rate of diesel oil in the fine sand material increases slightly with increasing initial water content. The diesel oil saturated conductivity(Kdiesel) decreases with increasing bulk density for the silty clay loam column. Diesel oil sorptivity(S) decreases linearly with increased initial water content and bulk density of the silty clay loam material. Changes in empirical parameters relative to initial water content and bulk density are similar to the parameter S. 展开更多
关键词 INFILTRATION diesel oil SOIL physical and empirical models initial water content bulk density
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丙烯酸-2,4,6-三硝基苯乙酯的合成及热分解 被引量:2
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作者 刘强强 金波 +3 位作者 彭汝芳 舒远杰 楚士晋 董海山 《含能材料》 EI CAS CSCD 北大核心 2012年第5期579-582,共4页
以TNT、甲醛为原料,在弱碱性条件下反应合成得到2,4,6-三硝基苯乙醇(PicCH2CH2OH);PicCH2CH2OH在浓硫酸催化下和丙烯酸在甲苯中回流反应24h,合成得到丙烯酸-2,4,6-三硝基苯乙酯,产率为62%。采用紫外可见光谱(UV-Vis)、核磁共振氢谱(1HN... 以TNT、甲醛为原料,在弱碱性条件下反应合成得到2,4,6-三硝基苯乙醇(PicCH2CH2OH);PicCH2CH2OH在浓硫酸催化下和丙烯酸在甲苯中回流反应24h,合成得到丙烯酸-2,4,6-三硝基苯乙酯,产率为62%。采用紫外可见光谱(UV-Vis)、核磁共振氢谱(1HNMR)、红外光谱(FTIR)、质谱(MS)以及元素分析等对产物结构进行了表征。利用热重分析(TG)对产物热稳定性进行了研究,采用Kissinger方法和Ozawa方法计算其热分解活化能Ea分别为99.78,102.96kJ·mol-1。 展开更多
关键词 有机化学 2 4 6-三硝基苯乙醇 丙烯酸-2 4 6-三硝基苯乙酯 热稳定性 活化能
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