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杨树新品种窄冠品系(斯×施、钻×俄、A118)
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《中国科技成果》 2004年第17期64-64,共1页
关键词 杨树 窄冠品系 人工杂交 斯×施 钻×俄 A118 农田防护林 固沙林 植树绿化
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Fertilizer Overuse in China:Empirical Evidence from Farmers in Four Provinces 被引量:8
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作者 栾昊 仇焕广 《Agricultural Science & Technology》 CAS 2013年第1期193-196,共4页
[Objective] This paper aims to empirically analyze the situation of fertilizer overuse in China, considering that fertilizer, important for China's crop production, has brought serious environmental pollution to Chin... [Objective] This paper aims to empirically analyze the situation of fertilizer overuse in China, considering that fertilizer, important for China's crop production, has brought serious environmental pollution to China due to over application. [Method] Based on field survey data in four provinces of China, the magnitude of fertilizer overuse at farm level was empirically analyzed with Cobb-Douglas Produc- tion Function Method and profit optimization theory in the research. [Result] The resuits show that by average, 110.5 kg of chemical fertilizer were applied per mu of land, and 46.9 kg fertilizer was overused, occupying 42.5%. [Conclusion] There is large potential to reduce the overused amount and it is of great importance to re- duce fertilizer overuse effectively, which needs further intensive study. 展开更多
关键词 Fertilizer overuse Cobb-Douglas Production Function Environmental pollution
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Collaborative planning approach for anti-bioterrorism emergency facility location based on aerodynamics
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作者 刘明 赵林度 《Journal of Southeast University(English Edition)》 EI CAS 2007年第S1期105-110,共6页
To smooth the correlation process from bio-virus diffusion to emergency relief response,the Gaussian plume model is used to describe the diffusion of dangerous sources,where the bio-virus concentration at any given po... To smooth the correlation process from bio-virus diffusion to emergency relief response,the Gaussian plume model is used to describe the diffusion of dangerous sources,where the bio-virus concentration at any given point in affected areas can be calculated.And the toxic load rule is introduced to define the borderline of the dangerous area at different levels.Combined with this,different emergency levels of different demand points in dangerous areas are confirmed using fuzzy clustering,which allows demand points at the same emergency level to cluster in a group.Some effective emergency relief centers are chosen from the candidate hospitals which are located in different emergency level affected areas by set covering.Bioterrorism experiments which were conducted in Nanjing,Jiangsu province are simulated,and the results indicate that the novel method can be used efficiently by decision makers during an actual anti-bioterrorism relief. 展开更多
关键词 emergency facility location Gaussian plume model(GPM) toxic load rule fuzzy clustering set covering
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Aperiodic stochastic resonance in Schmitt trigger
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作者 段江海 宋爱国 王一清 《Journal of Southeast University(English Edition)》 EI CAS 2003年第2期114-116,共3页
By the use of cross-correlation measures, the response of a symmetric Schmitt trigger (ST) driven by a random binary signal and white Gaussian noise is investigated. The results show that the information transmission... By the use of cross-correlation measures, the response of a symmetric Schmitt trigger (ST) driven by a random binary signal and white Gaussian noise is investigated. The results show that the information transmission can be enhanced when a certain amount of noise is presented, i.e., aperiodic stochastic resonance (ASR). Then, the influence of signal amplitude and the ST threshold on ASR is examined, the applicability of the ST in reducing the noise level of random signal transmission and improving the quality of output signal via ASR effect is illustrated. This research is of great interest in the field of digital communications. 展开更多
关键词 aperiodic stochastic resonance Schmitt trigger CROSS-CORRELATION
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Administrative Urbanization and City-making in Post-reform China: A Case Study of Ordos City, Inner Mongolia 被引量:4
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作者 YIN Guanwen LIU Yungang 《Chinese Geographical Science》 SCIE CSCD 2017年第6期891-903,共13页
In post-reform China, local governments, instead of the central state, have become major promoters of urbanization. Differing from the existing literature based on Western theories, this article argues that a localize... In post-reform China, local governments, instead of the central state, have become major promoters of urbanization. Differing from the existing literature based on Western theories, this article argues that a localized perspective, ‘administrative urbanization', can provide a contextual explanation for the mechanism of urbanization in the reform era. The case study of Ordos indicates that new town construction, especially in the inland area, has become the main strategy for investment attraction and economic development. The local government has played a dominant role in this construction through a series of administrative measures, including avoidance of central state regulations, land leasing, high standard infrastructure construction, relocation policies and industrial attraction. This article also explores the issue of unsustainability in the new town, and identifies that underdeveloped industrialization, slow population agglomeration and real estate bubbles are primary threats to the sustainability of administrative urbanization. 展开更多
关键词 administrative urbanization local government sustainability ORDOS China
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Preventing Coal and Gas Outburst Using Methane Hydration 被引量:29
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作者 吴强 何学秋 《Journal of China University of Mining and Technology》 2003年第1期7-10,共4页
According to the characteristics of the methane hydrate condensing and accumulating methane, authors put forward a new technique thought way to prevent the accident of coal and gas outburst by urging the methane in th... According to the characteristics of the methane hydrate condensing and accumulating methane, authors put forward a new technique thought way to prevent the accident of coal and gas outburst by urging the methane in the coal seams to form hydrate. The paper analyzes the feasibility of forming the methane hydrate in the coal seam from the several sides, such as, temperature,pressure, and gas components, and the primary trial results indicate the problems should be settled before the industrialization appliance realized. 展开更多
关键词 methane hydrate GAS coalbed temperature PRESSURE coal and gas outburst
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Experimental study on gas explosion suppression based on ferrocene 被引量:4
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作者 Ming-Gao YU Kai ZHENG +1 位作者 Li-Gang ZHENG Xiao-Ping WEN 《Journal of Coal Science & Engineering(China)》 2013年第3期358-362,共5页
In order to study the gas explosion suppression performance based on ferrocene, the self-constructed experimental facility was used to accomplish the experiment of gas explosion suppression. By means of thermogravimet... In order to study the gas explosion suppression performance based on ferrocene, the self-constructed experimental facility was used to accomplish the experiment of gas explosion suppression. By means of thermogravimetric analysis, the thermal characteristics of ferrocene have been gotten and the gas explosion suppression mechanism of ferrocene has been analyzed. The results show that ferrocene had good effects on gas explosion suppression, and the explosion pressure and flame propagation speed declined obviously. When ferrocene concentration is 0.08 g/L and methane volume concentration is 9.5%, the maximum explosion overpressure and maximum flame propagation speed of methane-air respectively decreased by about 59.5% and 19.6%, respectively. TG and DSC curves showed that the mass loss of ferrocene consists of two processes, which are sublimation and lattice fracture. The temperature of mass loss ranged from 128 ℃ to 230 ℃. The results showed profoundly theoretical significance to gas explosion suppression by ferrocene in coal mines. 展开更多
关键词 FERROCENE gas explosion THERMOGRAVIMETRIC mass loss explosion suppression mechanism
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Developing a risk assessment system for gas tunnel disasters in China 被引量:6
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作者 KANG Xiao-bing LUO Sheng +2 位作者 LI Qing-shan XU Mo LI Qiang 《Journal of Mountain Science》 SCIE CSCD 2017年第9期1751-1762,共12页
Gas disasters always restrict the tunnel constructions in mountain area, which becomes a major geological barrier against the development of underground engineering. China is rich in coal resources and has a large amo... Gas disasters always restrict the tunnel constructions in mountain area, which becomes a major geological barrier against the development of underground engineering. China is rich in coal resources and has a large amount of gas with a wide range of distribution. However, China experienced not only adverse effects on coal mining but also gas disasters in underground engineering construction, such as tunnels and chambers. With the increased number of tunnels passing through coal-bearing strata, the incidence of gas accidents is also rising. Therefore, the significance of preventing and mitigating gas disasters should be emphasized, and an effective risk assessment method for gas disasters should be established. On the basis of research on over 100 gas tunnels in China, a relatively ideal gas disaster risk assessment method and system for tunnels are established through the following measures. Firstly, geo-environmental conditions and gas situations were analyzed during construction. Secondly, qualitative analysis was combined with quantitative analysis. Finally, the influencing factors of gas disasters, including geological conditions, gas,and human factors, were investigated. The gas tunnel risk assessment system includes three levels:(1) the grading assessment of a gas tunnel during the planning stage,(2) the risk assessment of gas tunnel construction during the design and construction stages,(3) the gas tunnel outburst risk assessment during the coal uncovering stage. This system was applied to the dynamic assessment of gas disaster during the construction of the Zipingpu tunnel of Dujiangyan–Wenchuan Highway(in Sichuan, Southwest China). The assessment results were consistent with the actual excavation, which verified the rationality and feasibility of the system. The developed system was believed to be back-up and applied for risk assessment of gas disaster in the underground engineering construction. 展开更多
关键词 Tunnel engineering Gas disasters Risk assessment Index system Zipingpu tunnel
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Donor Centers in a Gaussian Potential
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作者 XIE Wen-Fang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第1期167-170,共4页
We study a neutral donor center (D^0) and a negatively charged donor center (D^-) trapped by a quantum dot, which is subjected to a Gaussian potential confinement. Calculations are made by using the method of nume... We study a neutral donor center (D^0) and a negatively charged donor center (D^-) trapped by a quantum dot, which is subjected to a Gaussian potential confinement. Calculations are made by using the method of numerical diagonalization of Hamiltonian within the effective-mass approximation. The dependence of the ground state of the neutral shallow donor and the negatively charged donor on the dot size and the potential depth is investigated. The same calculations performed with the parabolic approximation of the Gaussian potential lead to the results that are qualitatively and quantitatively different from each other. 展开更多
关键词 DONOR quantum dots
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Minimum safe thickness of rock plug in karst tunnel according to upper bound theorem 被引量:12
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作者 YANG Zi-han ZHANG Jia-hua 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第9期2346-2353,共8页
High pressure and water-bearing caverns ahead of a karst tunnel face tend to cause geological disasters, such as water and mud bursts. So, the determination of safe thickness of the reserved rock plug is a key technic... High pressure and water-bearing caverns ahead of a karst tunnel face tend to cause geological disasters, such as water and mud bursts. So, the determination of safe thickness of the reserved rock plug is a key technical problem to be solved for karst tunnel construction. Based on the Hoek-Brown nonlinear failure criterion, the minimum safe thickness of rock plug was investigated in the light of the limit analysis theory. On the basis of the proposed failure mode, the expression of the minimum thickness for rock plug was obtained by means of upper bound theorem in combination with variational principle. The calculation results show the influence of each parameter on safe thickness and reveal the damage range of rock plug. The proposed method is verified by comparing the results with those of the drain cavern of Maluqing Tunnel. The research shows that with the increase of compressive strength and tensile strength as well as constant A of Hoek-Brown criterion, the safe thickness decreases, whereas with the increase of cavern pressure, tunnel diameter, and constant B from Hoek-Brown criterion, the safe thickness increases. Besides, the tensile strength, or constants A and B affect the shear failure angle of rock plug structure, but other parameters do not. In conclusion, the proposed method can predict the minimum safe thickness of rock plug, and is useful for water burst study and prevention measures of tunnels constructed in high-risk karst regions. 展开更多
关键词 karst tunnels rock plug minimum safe thickness upper limit theorem failure mode
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Mechanical-Mathematical Modeling and Monitoring for Landslide Processes
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作者 V. Svalova 《Journal of Environmental Science and Engineering》 2011年第10期1282-1287,共6页
Landslides are one of the most widespread and dangerous phenomena in the urbanized territories. In Moscow they affect about 3% of the most valuable territory, including churches and historical buildings located at hig... Landslides are one of the most widespread and dangerous phenomena in the urbanized territories. In Moscow they affect about 3% of the most valuable territory, including churches and historical buildings located at high banks of the Moskva River. Recently the landslide activation occurred. Normal functioning of city infrastructure and implementation of effective slope protection measures require special landslide monitoring. Mechanical-mathematical model of high viscous fluid was applied for the landslide-prone slopes modeling. Equation of continuityand an approximatedNavier-Stockes equation f or slow motions in a thin layer were used. The results of modelling give possibility to define the landslide section with upmost velocity that should be monitored in the first place. Some important parameters used for numerical modelling can be defined from monitoring data. 展开更多
关键词 Landslide modeling MONITORING viscous fluid Navier-Stockes equation.
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Issues in the outburst prevention work of coal mines in Guizhou Province and the analysis of its countermeasures
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作者 LI Qing-song LI Xiao-hua MA Shu 《Journal of Coal Science & Engineering(China)》 2011年第2期152-156,共5页
In order to reduce the occurrence of coal and gas outburst accidents, and improve the capability to prevent gas hazards and realize the safe and efficient mining of coal enterprises. The distribution of the outburst c... In order to reduce the occurrence of coal and gas outburst accidents, and improve the capability to prevent gas hazards and realize the safe and efficient mining of coal enterprises. The distribution of the outburst coal mining area of Guizhou Province and the status of coal and gas outburst and the problems in the current outburst prevention methods were analyzed. The main issues were pointed out such as the lack of regional outburst prevention measures, unsatisfactory effect in drainage, poor management and implementation, as well as personnel that need more training. The prevention situation of coal and gas outburst in Guizhou Province was considered. In accordance with the above problems, from the perspective of strengthening geological exploration, testing coal seam parameters, studying outburst prevention technologies, deploying mining systems rationally, improving mine safety management systems, and strengthening protection facilities and other aspects, a targeted outburst prevention measure and proposals were put forward. 展开更多
关键词 coal and gas outburst prevention problem COUNTERMEASURE
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Fundamentalism: Militancy or Militarism?
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作者 Hongie Godlove Ngwochu 《Sociology Study》 2013年第11期815-824,共10页
The foundational and survival principles of all religions are shrouded in rituals, narratives, origin-stories, cultic practices, casuistries, taboos, mythical figures and institutions of authority. However, through ou... The foundational and survival principles of all religions are shrouded in rituals, narratives, origin-stories, cultic practices, casuistries, taboos, mythical figures and institutions of authority. However, through out history, religions have been threatened by politico-military and religious aggressions from other peoples, by heterodoxies, alternative origin-stories, practices and beliefs. These threats became unprecedented with the advent of Modernity. Faced with these destabilizing agents, they resorted to citing textual authorities, strengthening their institutions, giving leaders more powers, precisely defining belief commitments, punishing heretics and using violence against heterodoxies. Consequently, in their obsessive quest for preserving the sanctity of their faiths against modern threats, religions or section of a religion adopted both revival and resistant measures. Fundamentalism thus developed within these contexts. This paper intends to reveal that religious militancy and militarism are ramifications of Fundamentalism. It argues that Modernity's destabilizing agents to religions and religions' passionate desire for self-protective steps, militant or militaristic, yield to the phenomenon of Fundamentalism. Secondary sources were used to assemble the data while analytical and comparative approaches with empirical emphases on Christianity and Islam were used to weave the findings with the finality that militant or militaristic, Fundamentalism is religions' obsessive response to Modernity, 展开更多
关键词 RELIGION Modernity FUNDAMENTALISM MILITANCY MILITARISM
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Outburst control technology for rapid excavation in severe outburst coal
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作者 QU Yang 《Journal of Coal Science & Engineering(China)》 2010年第1期53-56,共4页
The advantages and disadvantages of various outburst prevention measures inheading face were analyzed.The mechanism of outburst prevention about hydraulic extrusionmeasure was studied, the technological parameters wer... The advantages and disadvantages of various outburst prevention measures inheading face were analyzed.The mechanism of outburst prevention about hydraulic extrusionmeasure was studied, the technological parameters were introduced, and the effectof outburst prevention was investigated.The in-situ experimental results show that thehydraulic extrusion measures are applied in serious outburst mine, not only the stress ofstimulate outburst is eliminated effectively but also the gas in coal seam is released efficiently,the measures get obvious effect on coal and gas outburst prevention, and theroadway driving speed is increased by 1.5 times, implementing a safe and rapid excavation. 展开更多
关键词 mechanism of outburst prevention outburst prevention measure rapid excavation hydraulic extrusion water iniection
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Long Run Relationships, Vertical Integration and International Competition: Can They Contribute to Explaining Regional Construction Cost Differences?
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作者 Abukar Warsame 《Journal of Civil Engineering and Architecture》 2014年第3期378-387,共10页
The existence of opportunistic behavior by contractors or sub-contractors in the bidding process encouraged by the governance structure of construction companies as well as the kind of relationship that exist between ... The existence of opportunistic behavior by contractors or sub-contractors in the bidding process encouraged by the governance structure of construction companies as well as the kind of relationship that exist between contractors and clients is thought to have some bearing on the rising construction cost observed in some regions of Sweden. Three hypotheses that are intended to test the impact that long run relationship between contractors and developers, vertically integrated firms, and the increase of international competition could have on the construction cost increase levels were tested on a predetermined number of projects from six cities in different regions. The semi-structured survey produces inconclusive results. Long run and collaborative relationship was prevalent in small region though respondents in this region did not draw strong connection between construction cost increase levels and the kind of observed relationship. In Stockholm region, short-term relationship was mostly prevalent. Vertical integration and foreign competition impacts on construction costs were not significant in either region. 展开更多
关键词 Construction costs COMPETITION long-term relationship vertical integration.
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Great Silk Road on the Territory of Kazakhstan: From Past to Future 被引量:1
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作者 Akhmetkal MEDEU Maulken ASKAROVA +2 位作者 Roman PLOKHIKH Irina SKORINTSEVA Aruzhan BEKKULIYEVA 《Journal of Resources and Ecology》 CSCD 2015年第2期114-118,共5页
The Great Silk Road is a trade route linking the East and West which gave impetus to the development of ancient society, and Kazakhstan is the heart of the trade route. At the initial stage, intensive transaction of g... The Great Silk Road is a trade route linking the East and West which gave impetus to the development of ancient society, and Kazakhstan is the heart of the trade route. At the initial stage, intensive transaction of goods took place between the West and East through The Great Silk Road. This paper reviewed the history of development of the Silk Road and suggested that today to construct the "New Silk Road", Kazakhstan should face many issues, and take many steps to become a Eurasian hub through taking full of advantages. Above all, developing mechanisms of integration and sustainable development is our urgent need. 展开更多
关键词 Great Silk Road Kazakhstan HISTORY construction measures
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Using the contact network model and Metropolis-Hastings sampling to reconstruct the COVID-19 spread on the “Diamond Princess” 被引量:10
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作者 Feng Liu Xin Li Gaofeng Zhu 《Science Bulletin》 SCIE EI CAS CSCD 2020年第15期1297-1305,M0004,共10页
Traditional compartmental models such as SIR(susceptible,infected,recovered)assume that the epidemic transmits in a homogeneous population,but the real contact patterns in epidemics are heterogeneous.Employing a more ... Traditional compartmental models such as SIR(susceptible,infected,recovered)assume that the epidemic transmits in a homogeneous population,but the real contact patterns in epidemics are heterogeneous.Employing a more realistic model that considers heterogeneous contact is consequently necessary.Here,we use a contact network to reconstruct unprotected,protected contact,and airborne spread to simulate the two-stages outbreak of COVID-19(coronavirus disease 2019)on the‘‘Diamond Princess"cruise ship.We employ Bayesian inference and Metropolis-Hastings sampling to estimate the model parameters and quantify the uncertainties by the ensemble simulation technique.During the early epidemic with intensive social contacts,the results reveal that the average transmissibility t was 0.026 and the basic reproductive number R0 was 6.94,triple that in the WHO report,indicating that all people would be infected in one month.The t and R0 decreased to 0.0007 and 0.2 when quarantine was implemented.The reconstruction suggests that diluting the airborne virus concentration in closed settings is useful in addition to isolation,and high-risk susceptible should follow rigorous prevention measures in case exposed.This study can provide useful implications for control and prevention measures for the other cruise ships and closed settings. 展开更多
关键词 Contact network model SMALL-WORLD Chain-binomial model Airborne spread TRANSMISSIBILITY The basic reproductive number R0
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