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81.
郭京帅 《信阳农业高等专科学校学报》2013,23(2):136-138
中外合作办学是我国高等教育人才培养模式的一种拓展方式。双校园模式诸如"3+1"、"2+2"、"1+3"、"1+2+1"、"3+2"等已成为我国中外合作办学的主流,这促使大学英语的角色定位限定在雅思和托福培训上。保持当前大学英语应试教育的优势,适当融入中西文化内容,处理好与专业英语教育的关系,无疑是"双校园"模式下大学英语教学应该积极扮演的角色。 相似文献
82.
B. Sterk M.K. van Ittersum C. Leeuwis W.A.H. Rossing H. van Keulen G.W.J. van de Ven 《Agricultural Systems》2006
Whole-farm design models quantitatively analyze the effects of a variety of potential changes at the farm system level. Science-driven technical information is confronted with value-driven objectives of farmers or other social groupings under explicit assumptions with respect to exogenous variables that are important drivers of agricultural systems (e.g., market conditions). Hence, farm design is an outcome of objective specification and the potential of a system. In recent publications, whole-farm design modelling has been proposed to enhance (farm) innovation processes. A number of operational modelling tools now offers the opportunity to assess the true potential of whole-farm design modelling to enhance innovation. In this paper, we demonstrate that it is not trivial to find niches for the application of goal-based farm models. Model outcomes appeared not to match questions of farm managers monitoring and learning from their own and other farmers’ practices. However, our research indicates that whole-farm design modelling possesses the capabilities to make a valuable contribution to reframing. Reframing is the phenomenon that people feel an urge to discuss and reconsider current objectives and perspectives on a problem. Reframing might take place in a situation (i) of mutually felt dependency between stakeholders, (ii) in which there is sufficient pressure and urgency for stakeholders to explore new problem definitions and make progress. Furthermore, our research suggests that the way the researcher enters a likely niche to introduce a model and/or his or her position in this niche may have significant implications for the potential of models to enhance an innovation process. Therefore, we hypothesize that the chances of capitalizing on modelling expertise are likely to be higher when researchers with such expertise are a logical and more or less permanent component of ongoing trajectories than when these researchers come from outside to purposefully search for a niche. 相似文献
83.
Parthenium hysterophorus is a weed of global significance causing severe economic, environmental, human and animal health problems in Asia, Africa, Australia and the Pacific. In South Asia, P. hysterophorus occurs in India, Pakistan, Sri Lanka, Bangladesh and Nepal. A host-specific leaf-feeding beetle Zygogramma bicolorata from México was introduced into India in 1984, as a biological control agent for P. hysterophorus . In this study, a GIS-based distribution map of P. hysterophorus and its biological control agent Z. bicolorata in South Asia based on meta-analysis is presented. The map highlights the limited published information on P. hysterophorus incidence in many of the states and territories in India, as well as in neighbouring Bangladesh, Bhutan, Nepal and Pakistan. Incidence of Z. bicolorata was recorded as three distinct clusters, covering many states in India. In Pakistan, Z. bicolorata was recorded in the Punjab region bordering India. A CLIMEX model based on the current distribution of Z. bicolorata in India suggests that the geographic range of this agent in India and Pakistan can extend to other P. hysterophorus -infested areas in the region. The CLIMEX model also suggests that all of Bangladesh and Sri Lanka, and parts of Nepal are climatically suitable for Z. bicolorata. 相似文献
84.
The rapid expansion of the alien invasive Parthenium hysterophorus is a new agricultural and environmental problem for Nepal. Although the weed was first recorded in 1967, the most significant expansion has occurred in the last 20 years. The weed is thought to have entered Nepal from India and currently is found in the Tarai, Siwalik and hill regions of Nepal. A CLIMEX modelling projection has shown these regions to be climatically suitable for the growth of P. hysterophorus, both under the present and a future projected increased temperature. From the initially invaded roadside vegetation, the weed has now spread into cropping land and forests. Vehicle movement and transportation of agriculture products are the main means by which its seed is spreading. The weed has reduced plant species richness and changed species composition in grasslands, while fodder collectors have developed contact dermatitis from the plant. To date, no sustainable management strategy has been developed for this weed. However, the fortuitous arrival of the biological control agents Zygogramma bicolorata and Puccinia abrupta var. partheniicola has had some impact upon the weed's growth and abundance. A CLIMEX modelling projection identifies many suitable locations for Z. bicolorata outside of its present range and within areas where the weed is likely to spread, both under the present and under a future projected climate of increased temperature. Mapping of the currently invaded areas, management through community involvement and further releases of new and redistribution of current biological control agents are required to manage P. hysterophorus in Nepal. 相似文献
85.
原油管道外腐蚀风险评价 总被引:2,自引:0,他引:2
介绍了应用解析法评估腐蚀管道失效风险的方法,根据ASME B 31 G和DNV等规范建立了腐蚀管道失效概率计算模型,结合国外管道事故统计结果,应用伯努利能量方程建立了后果评价模型,论述了建立风险可接受标准的方法. 相似文献
86.
旅游发展中利益相关者环境意识水平分析 总被引:3,自引:1,他引:3
环境意识作为一种新的独立意识形态,能够规范社区与社会的生活方式和经济活动方式.因此,旅游发展的生态安全状态取决于直接利益相关者的环境意识水平以及他们之间的相互利益协调关系,主要包括:旅游管理部门、旅游者、旅游企业和当地社区。文中根据环境意识结构,设计了旅游环境意识调查问卷,其主要的指标体系包括:旅游环境知识水平、旅游环境态度、旅游环境评价和旅游环境行为四个方面。并设计了环境意识总体评价模型,以此来计算旅游发展中旅游环境意识水平的综合得分。经过分析得知,旅游管理部门的环境意识水平最高,其次是社区居民,再次是旅游企业,最后是旅游者,而且总体水平都不高。所以,在旅游发展中必须提高各利益相关者的旅游环境意识水平,推动他们自觉参与保护旅游生态环境安全的行动中来。 相似文献
87.
水工弧形闸门流激振动的改进简化力学模型 总被引:3,自引:0,他引:3
对弧形闸门危害性的流激振动进行振动控制,其中前提之一是对闸门模型做适当的简化。利用三维有限元方法计算的结构动力特性与简化结构动力特性相等的原则修正弧形闸门简化力学模型,并确定了等效的弧形闸门三维简化结构模型和系统参数。分析和计算表明,建立的简化三维力学模型较好地反映了弧形闸门结构的动力特性和随机脉动压力下的振动反应,可用于安装阻尼器的弧形闸门的智能控制设计。 相似文献
88.
The FAO basal crop coefficient Kcb and the soil evaporation coefficient Ke for a sparse sorghum field in one growing season were estimated using the compartment model (Shuttleworth–Wallace model; S–W model), which separately estimates transpiration from crops and evaporation from the soil. The Kcb had a low value of 0.10 (Kcb, ini) during the initial period, increased rapidly to a maximum of 0.98 (Kcb, mid) at midseason, and decreased rapidly to 0.53 (Kcb, end) by the end of the growing season. The Kcb increased with increasing leaf area index (LAI) rapidly and slowly, respectively, below and above an LAI of 1.0. The Ke showed a positive relationship to increasing soil water content (SWC) at a depth of −15.0 cm, but the soil water content indicated a negative relationship to increasing LAI. Using the dual crop coefficients derived by their relationships to the LAI and soil water content, the actual evapotranspiration (ETa) was estimated and compared to the ETa derived by the Bowen ratio energy budget (BREB) method. The root mean square error (RMSE) of the ETa obtained from the simulated crop coefficient to the ETa obtained by the BREB method was 0.84 mm day−1. Thus, the adjusted relationship of Kcb and Ke allowed a good estimation of the evapotranspiration in an irrigated field with sparse vegetation cover. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
89.
The net is regarded as the most critical component in marine aquaculture facilities as it is the only barrier which protects the environment from fish escapes. Accurate predictions of the net cage deformation and drag force on the nets are needed, both for ensuring fish welfare and for dimensioning of the mooring system. Thus, an appropriate hydrodynamic model is essential. In practice, two types of hydrodynamic force models, i.e., the Morison type and the Screen type, are commonly used to calculate the hydrodynamic forces on nets. Application of the models depends on the underlying structural model and the availability of data. A systematic review of hydrodynamic models is therefore undertaken to compare the models and various parameterisations, in aid of model selection during the design. In this study, eleven commonly used hydrodynamic models, i.e., five Morison models and six Screen models, are reviewed comprehensively, and implemented into a general finite element (FE) solver for dynamic simulations. Sensitivity studies on different current velocities, inflow angles and solidities of the nets are carried out. Moreover, different wake effects are also considered in numerical simulations. The numerical results from different models are compared against existing experimental data under pure current conditions. Suggestions for selection of suitable hydrodynamic models are provided, based on the model comparison. 相似文献
90.
输气管道优化设计新模型 总被引:4,自引:1,他引:4
传统的输气管道优化设计模型设计变量多、约束条件多而且复杂,优化速度慢,优化结果不理想.提出了一种新的模型,该模型具有设计变量少、约束条件少而且简单的特点,提高了优化速度.对优化算法进行了改进,使得优化结果为全局最优解.给出了算例,证明输气管道优化设计新模型十分有效. 相似文献