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Dispersion function of Rayleigh waves in porous layered half-space system
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作者 阎守国 谢馥励 +1 位作者 李长征 张碧星 《Applied Geophysics》 SCIE CSCD 2016年第2期333-342,419,共11页
Rayleigh wave exploration is based on an elastic layered half-space model. If practical formations contain porous layers, these layers need to be simplified as an elastic medium. We studied the effects of this simplif... Rayleigh wave exploration is based on an elastic layered half-space model. If practical formations contain porous layers, these layers need to be simplified as an elastic medium. We studied the effects of this simplification on the results of Rayleigh wave exploration. Using a half-space model with coexisting porous and elastic layers, we derived the dispersion functions of Rayleigh waves in a porous layered half-space system with porous layers at different depths, and the problem of transferring variables to matrices of different orders is solved. To solve the significant digit overflow in the multiplication of transfer matrices, we propose a simple, effective method. Results suggest that dispersion curves differ in a low- frequency region when a porous layer is at the surface; otherwise, the difference is small. 展开更多
关键词 layered media porous media Rayleigh waves matrix optimization
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Strategies for Jointly Enhancing Water Use Efficiency and Yield of Crops in the North China Plain
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作者 黄桂荣 刘晓英 钟秀丽 《Agricultural Science & Technology》 CAS 2014年第12期2064-2068,共5页
The North China Plain (NCP) is one of the most important agricultural re- gions in China, but it is experiencing a serious water-resource crisis due to exces- sive exploitation of groundwater reserves. Improving wat... The North China Plain (NCP) is one of the most important agricultural re- gions in China, but it is experiencing a serious water-resource crisis due to exces- sive exploitation of groundwater reserves. Improving water-use efficiency (WUE) of crops is thought to have good potential for conserving groundwater and in maintain- ing high crop production in the region, In this paper, firstly, strategies for improving WUE of crop cultivars in the NCP were discussed. According to studies on key factors affecting cultivar WUE, stomatal conductance, which has large genotypic variability and differs among cultivars in response to drought, is an important physio- logical trait associating closely with the performance of cultivars in WUE and yield. Higher WUE and higher yield may be obtained through strategies of cultivar adop- tion with appropriate stomatal characteristics suitable to different conditions of water availability. Secondly, irrigation scheduling in the North China Plain was further dis- cussed. The irrigation frequency currently employed in this area could be reduced by at least one application (from four to three applications) to obtain higher produc- tion and also higher WUE. Finally, straw mulching and the use of early vigor culti- vats were suggested as two practices that had the potential to be effective in in- creasing crop WUE. 展开更多
关键词 Water use efficiency YIELD Stomatal conductance IRRIGATION Water deficit
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Comparison of Gas Exchange Characteristic in Leaves of Soybean Varieties with Different Yield Levels
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作者 耿艳秋 张治安 +2 位作者 李大勇 赵洪祥 郑洪兵 《Agricultural Science & Technology》 CAS 2010年第8期98-101,共4页
[Objective] The aim was to explore the gases exchange characteristic in leaves of soybean cultivars at different yield levels to provide a certain theories basis for high yield breeding and cultivation of soybean cult... [Objective] The aim was to explore the gases exchange characteristic in leaves of soybean cultivars at different yield levels to provide a certain theories basis for high yield breeding and cultivation of soybean cultivars. [Method] Nine soybean cultivars divided into three yield levels were planted under the same environmental condition. At V4(seedling),R2(blooming),R4(pod-bearing),R6(pod-filling) and R7(maturing) growth stages,the net photosynthetic rate (Pn),stomatal conductance (Gs) and transpiration rate (Tr) in soybean leaves were measured with Li-6400 portable photosynthesis system. [Result] At all growth stages,the net photosynthetic rate,stomatal conductance in leaves of high yield soybean cultivars were significantly higher than low yield soybean cultivars. At V4,R2 and R4 stages,transpiration rate in leaves of high yield soybean cultivars was significantly higher than low yield soybean cultivars; there was no significant difference on transpiration rate in leaves of soybean cultivars at different yield levels at R6 and R7 stage. At V4 and R2 stage,water use efficiency (WUE) in leaves of soybean cultivars at different yield showed a trend of low yield cultivarsmiddle yield cultivarshigh yield cultivars,while it appeared high yield cultivarsmiddle yield cultivarslow yield cultivars at R4,R6 and R7 stage. [Conclusion] The gases exchange capacity in leaves of high yield soybean cultivars was significantly higher than low yield soybean cultivars,which had provided physiological basis of high yield. The net photosynthetic rate could be used as an selection index of high yield soybean. 展开更多
关键词 SOYBEAN Net photosynthetic rate Stomatal conductance Transpiration rate Water use efficiency
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Effects of Different Irrigation Amounts on Physiological Indexes and Water Use Efficiency of Rice at the Jointing-booting Stage 被引量:1
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作者 李轲 景元书 +1 位作者 谭孟祥 薛杨 《Agricultural Science & Technology》 CAS 2017年第11期2014-2018,2025,共6页
[Objective] This study was conducted to investigate the effects of different irrigation amounts on rice leaf physiology and water use efficiency. [Method] The irrigation test with three different treatments was carrie... [Objective] This study was conducted to investigate the effects of different irrigation amounts on rice leaf physiology and water use efficiency. [Method] The irrigation test with three different treatments was carried out in the Agrometeo- rological Experimental Station of Nanjing University of Information Science & Technology. [Reset] Under flood irrigation, the rice leaf temperature was lower than wet irrigation by 0.4-0.7 ℃; when the strength of photosynthetically active radiation was in the range of 800-1 800 gmol/(m^2·s), the average stomatal conductance of rice leaves under flood irrigation was higher than that of the wet irrigation treatment by 0.123-0.183 mol H2O/(m^2·s), and the leaf water use efficiency was higher than that of the wet irrigation treatment by 0.24 g/kg; after 10:00 every day, the water use efficiency under flood irrigation was always higher than that of the wet irrigation treatment; and compared with the wet irrigation treatment, the rice of the flood irrigation treatments had higher leaf water use efficiency, and final yields were also remarkably improved by 5.89%-13.97%. [Conclusion] This study will provide a practical reference basis for field management. 展开更多
关键词 Stomatal conductance RICE Water use efficiency YIELD
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Interaction of two three-dimensional explosion bubbles 被引量:2
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作者 YAO Xiong-liang ZHANG A-man LIU Yu-chen 《Journal of Marine Science and Application》 2007年第2期12-18,共7页
The interaction of two underwater explosion bubbles was mathematically analyzed in this paper. Based on the assumption of potential flow, high-order curved elements were used to discretize the boundary integral equati... The interaction of two underwater explosion bubbles was mathematically analyzed in this paper. Based on the assumption of potential flow, high-order curved elements were used to discretize the boundary integral equation and solve it. Assuming that gas inside the bubble follows the isentropic rule, the Euler-Lagrange method was used to trace the evolution of the bubble, and when calculating the singular integral, the singularity of the double-layer singular integral was eliminated by reconstructing a principal-value integral of double-layer potential so that a more precise result could be obtained. Elastic mesh technique (EMT) was also used when tracing the evolution of the bubble interface, and numerical smoothing wasn't needed. A comparison of calculations using this three-dimensional model with results of the Reyleigh-Plesset bubble model shows that the three-dimensional model and calculation method in this paper is practical. This three-dimensional model was applied to simulate the interaction of two bubbles under the action of gravity, and the dynamic characteristics of two bubbles near the surface was also analyzed. Bubbles influenced by surface effects and gravity present severe non-linearity. This paper provides a reference for research into the dynamics of multi-bubbles. 展开更多
关键词 two bubbles boundary integral EMT three-dimensional model
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The Influence of Confucius' Moral Standards on Wellbeing of Academics in Higher Education in China in the Context of the Chinese Dream
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作者 MA Wen-ying LIU Xi 《Journal of Literature and Art Studies》 2014年第12期1129-1133,共5页
The Chinese Dream, adopted by General Secretary Xi Jinping, was used and spread in China. It is about Chinese prosperity, collective effort, socialism and national glory. It is also about the welfare, wellbeing, and q... The Chinese Dream, adopted by General Secretary Xi Jinping, was used and spread in China. It is about Chinese prosperity, collective effort, socialism and national glory. It is also about the welfare, wellbeing, and quality of life of every Chinese. Academics in higher education in China are facing changes both across the globe and in China, they must take the challenges. This paper does research on wellbeing of the academics from the aspects of the definition of wellbeing, the situation both in the world and in China, the Chinese concept of happiness, the possible influence of Confucius moral standards on wellbeing of Chinese. This paper may help school leaders implement policies that foster effective work environment in the new era in China. 展开更多
关键词 wellbeing Confucius' moral standards the Chinese dream academics higher education China
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Hepatothorax due to a right diaphragmatic rupture related to duodenal ulcer perforation 被引量:1
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作者 Se-Jin Baek Jin Kim Sung-Ho Lee 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第39期5649-5652,共4页
Here, we present the case of a 53-year-old man with a hepatothorax due to a right diaphragmatic rupture related to duodenal ulcer perforation. On admission, the patient complained of severe acute abdominal pain, with ... Here, we present the case of a 53-year-old man with a hepatothorax due to a right diaphragmatic rupture related to duodenal ulcer perforation. On admission, the patient complained of severe acute abdominal pain, with physical examination findings suspicious for a perforated peptic ulcer. Of note, the patient had no history of other medical conditions or recent trauma, and the initial chest radiography and laboratory findings were not specific. A subsequent abdominal computed tomography revealed intrathoracic displacement of the liver, gallbladder, transverse colon and omentum through a right diaphragmatic defect. The patient then underwent an explorative laparotomy that confirmed duodenal ulcer perforation. A primary repair of the duodenal perforation was performed, and the diaphrag-matic defect was repaired using a polytetrafluoroeth-ylene patch after the organs were reduced and the cavity irrigated. This particular case proves interesting as right-sided spontaneous diaphragmatic ruptures are very rare and difficult to diagnose. Additionally, the best treatment for such large diaphragmatic defects is still controversial, especially in cases of intrathoracic or intra-abdominal contamination. 展开更多
关键词 Diaphragmatic rupture Hepatothorax Du-odenal ulcer perforation Polytetrafluoroethylene mesh
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Verification of the stomatal conductance of Nebbiolo grapevine
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作者 Stefania PRINO Federico SPANNA Claudio CASSARDO 《Journal of Chongqing University》 CAS 2009年第1期17-24,共8页
Wine is one of the most important Italian export products,and Nebbiolo is one of the most respected Italian grapes. In the summer of 2007,a measurement campaign was carried out in a Nebbiolo vineyard located in Vezza ... Wine is one of the most important Italian export products,and Nebbiolo is one of the most respected Italian grapes. In the summer of 2007,a measurement campaign was carried out in a Nebbiolo vineyard located in Vezza d’Alba,near Cuneo,Italy. Using a gauge of trade gases and some other instruments,we recorded the stomatal conductance and also some physiological parameters useful for estimating the dependence of stomatal conductance on environmental variables. The goal of this experiment was improving the parameterization of grapevine evapotranspiration through the assessment of the stomatal conductance and,in particular,of the functional dependence of the stomatal conductance on the following variables:the photosynthetically active radiation,the atmospheric temperature,the atmospheric moisture deficit,and the carbon dioxide concentration. The observations allowed us to check and,in some cases,to adapt the existing general parameterizations found in literature. The results showed some significant differences with the existing parameterizations concerning the atmospheric temperature,the atmospheric moisture deficit,and the carbon dioxide concentration. The parameterizations obtained in this experiment,although referring to a specific plant and site(namely the Nebbiolo at Vezza d’Alba),could allow assessment of the best environmental conditions under which the Nebbiolo grapevine production is the best,and in future could be tested for other grapevines or climates. 展开更多
关键词 GRAPEVINE EVAPOTRANSPIRATION stomatal conductance photosynthetically active radiation
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GF-3 data real-time processing method based on multi-satellite distributed data processing system 被引量:5
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作者 YANG Jun CAO Yan-dong +2 位作者 SUN Guang-cai XING Meng-dao GUO Liang 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第3期842-852,共11页
Due to the limited scenes that synthetic aperture radar(SAR)satellites can detect,the full-track utilization rate is not high.Because of the computing and storage limitation of one satellite,it is difficult to process... Due to the limited scenes that synthetic aperture radar(SAR)satellites can detect,the full-track utilization rate is not high.Because of the computing and storage limitation of one satellite,it is difficult to process large amounts of data of spaceborne synthetic aperture radars.It is proposed to use a new method of networked satellite data processing for improving the efficiency of data processing.A multi-satellite distributed SAR real-time processing method based on Chirp Scaling(CS)imaging algorithm is studied in this paper,and a distributed data processing system is built with field programmable gate array(FPGA)chips as the kernel.Different from the traditional CS algorithm processing,the system divides data processing into three stages.The computing tasks are reasonably allocated to different data processing units(i.e.,satellites)in each stage.The method effectively saves computing and storage resources of satellites,improves the utilization rate of a single satellite,and shortens the data processing time.Gaofen-3(GF-3)satellite SAR raw data is processed by the system,with the performance of the method verified. 展开更多
关键词 synthetic aperture radar full-track utilization rate distributed data processing CS imaging algorithm field programmable gate array Gaofen-3
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十月革命前的俄国讽刺杂志
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作者 侯丹 《文艺理论与批评》 CSSCI 北大核心 2017年第5期22-30,共9页
20世纪初的俄罗斯正处在一个社会思想迅速发展、沙皇统治行将就木的历史时期,文学成为各种思想交锋和政治运动的一部分,文学与政治斗争紧密地结合在一起,这在当时讽刺文学的创作中得到了鲜明的反映。文学发展的历史表明,越是在危机重重... 20世纪初的俄罗斯正处在一个社会思想迅速发展、沙皇统治行将就木的历史时期,文学成为各种思想交锋和政治运动的一部分,文学与政治斗争紧密地结合在一起,这在当时讽刺文学的创作中得到了鲜明的反映。文学发展的历史表明,越是在危机重重的历史时期,文学中"笑"的倾向往往越是强大。"笑"既是与沙皇专制统治进行斗争的武器,也是压抑环境中的一个透气孔,它的存在表明人们尚未失去心灵的健康和对未来的美好希望。 展开更多
关键词 讽刺文学 思想交锋 历史时期 利孔 透气孔 专制统治 萨蒂 萨沙 讽刺诗 俄罗斯文学
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雅典
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作者 帕拉马斯 罗洛 《诗刊》 北大核心 1991年第11期23-23,共1页
关键词 奥林帕斯 大神母 大阳 利孔 南兰 孔山 众神
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Impacts of Salinity and Nitrogen on the Photosynthetic Rate and Growth of Sunflowers(Helianthus annuus L.) 被引量:10
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作者 ZENG Wen-Zhi XU Chi +3 位作者 WU Jing-Wei HUANG Jie-Sheng ZHAO Qiang WU Mou-Song 《Pedosphere》 SCIE CAS CSCD 2014年第5期635-644,共10页
Understanding the interactions between salinity and fertilizers is of significant importance for enhancing crop yield and fertilizeruse efficiency. In this study a complete block design experiment was performed in the... Understanding the interactions between salinity and fertilizers is of significant importance for enhancing crop yield and fertilizeruse efficiency. In this study a complete block design experiment was performed in the Hetao Irrigation District of Inner Mongolia,China, to evaluate the effects of interactions between soil salinity and nitrogen(N) application rate on sunflower photosynthesis and growth and to determine the optimum N application rate for sunflower growth in the district. Four levels of soil salinity expressed as electrical conductivity(0.33–0.60, 0.60–1.22, 1.2–2.44, and 2.44–3.95 dS m-1) and three application rates of N fertilization(90, 135,and 180 kg ha-1) were applied to 36 micro-plots. Soil salinity inhibited the photosynthetic rate, stomatal conductance, transpiration rate, plant height, leaf area, and aboveground dry matter of sunflowers. The intercellular CO2 concentration first decreased and then increased with increasing soil salinity in the seedling stage, and the instantaneous leaf water-use efficiency fluctuated with soil salinity. The stomatal and non-stomatal limitations of sunflowers alternated in the seedling stage; however, in the bud, blooming,and mature stages, the stomatal limitation was prevalent when the salinity level was lower than 2.44 dS m-1, whereas the nonstomatal limitation was predominant above the salinity level. The application of N fertilizer alleviated the adverse effects of salinity on sunflower photosynthesis and growth to some extent. During some key growth periods, such as the seedling and bud stages, a moderate N application rate(135 kg ha-1) resulted in the maximum photosynthetic rate and yielded the maximum dry matter. We suggest a moderate N application rate(135 kg ha-1) for the Hetao Irrigation District and other sunflower-growing areas with similar ecological conditions. 展开更多
关键词 non-stomatal limitation N-use efficiency optimum N application rate soil salinization stomatal limitation
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Pore Size Distribution as a Soil Physical Quality Index for Agricultural and Pasture Soils in Northeastern Iran 被引量:4
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作者 H.SHAHAB H.EMAMI +1 位作者 G.H.HAGHNIA A.KARIMI 《Pedosphere》 SCIE CAS CSCD 2013年第3期312-320,共9页
Assessment of soil quality is important for optimum production and natural resources conservation. Agricultural and pasture soil qualities of Deh-Sorkh region located at south of Mashhad, northeastern Iran were assess... Assessment of soil quality is important for optimum production and natural resources conservation. Agricultural and pasture soil qualities of Deh-Sorkh region located at south of Mashhad, northeastern Iran were assessed using the integrated quality index (IQI) and Nemero quality index (NQI) models in combination with two datasets, i.e., total data set (TDS) and minimum data set (MDS). In this study 6 soil properties considered as MDS were selected out of 18 properties as TDS using principle component analysis. Soil samples were divided into 3 groups based on optimum ranges of 8 soil physical quality indicators. Soil samples with the most indicators at optimum range were selected as group 1 and the samples having fewer indicators at optimum range were located in groups 2 and 3. Optimum ranges of soil pore size distribution functions were also determined as soil physical quality indices based on 8 soil physical quality indicators. Pore size distribution curves of group 1 were considered as the optimum pore size functions. The results showed that relatively high organic carbon contents could improve pore size distribution. Mean comparisons of soil physical quality indicators demonstrated that mean weight diameter of wet aggregates, structural stability index, the slope of moisture retention curve at inflection point, and plant available water content in agricultural land use decreased significantly in relation to pasture land use. In addition, the results demonstrated that the studied MDS could be a suitable representative of TDS. 78% of pasture soils had the optimum pore size distribution functions, while this parameter for agricultural soils was only 13%. In general, the soils of the studied region showed high limitations for plant growth according to the studied indicators. 展开更多
关键词 integrated quality index land use minimum data set Nemero quality index soil quality
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