首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
An ELECTRE performance evaluation model was developed to outrank the different operating conditions of air conditioning systems. Five evaluation criteria covers total energy consumption, thermal comfort PMV and PPD, indoor air quality indices such as CO2 concentration and TVOC concentration. The performance under seven different operating conditions was outranked on the TRNSYS (transient system) simulation platform. Three assignment alternatives of weight coefficients were selected to calculate the relevant credibility scores respectively. The results indicate that the proposed evaluation model can outrank the different operating conditions and select the optimum one, Moreover different weight assignments have little influence on the outranking scores. Further investigation should focus on the more evaluating criteria such as control performance and others in the comprehensive evaluation of operating conditions.  相似文献   

2.
ABSTRACT In the area of travel behavior, route choice when facing congestion has been widely researched. However, there are other behavioral alternatives based on people's activities and adaptive decision‐making strategies that have been overlooked. This paper focuses on how and what kind of information is used when considering a subset of these alternatives. Alternatives examined are the final choice of people's decision‐making process when faced with unexpected events during the commute trip in the presence of real‐time information collected using GABRIEL (Gis Activity‐Based tRavel sImuLator) in Columbus, OH. An empirical analysis of the data set, which includes a limited set of alternatives (six in total) is presented. Bivariate analysis and multinomial logit models are used to identify variables that influence the choice. Results show that people are willing to experiment with other alternatives if provided the information to support their choice.  相似文献   

3.
生长促进用抗生素的大量使用导致细菌耐药性问题日趋严重,同时传统抗生素的研发已进入瓶颈期,给细菌感染性疾病的治疗带来许多不安因素。这种情况下抗生素替代品逐渐成为世界各国的研究热点。文章就抗菌疫苗、免疫调节剂、噬菌体及其裂解酶、抗菌多肽、微生态制剂、植物提取物、细菌致病力抑制剂以及饲用酶这8类抗生素替代品的研发进展及存在问题进行分析和讨论,得出以下结论:兽用抗生素替代品由于其局限性尚不能完全替代抗生素,只有建立科学的监控体系和继续开发完善抗生素替代品才能减少抗生素不规范使用带来的负面效应,保证动物性食品的安全,从而实现畜牧业的绿色和健康发展。  相似文献   

4.
Summary We review here the most recently developed technique for maize transformation which involves the vortexing of silicon carbide whiskers with maize cells in the presence of plasmid DNA. Fertile transgenic plants have been regenerated following whisker-mediated transformation which is compared with the alternatives described to date, namely protoplast uptake, particle bombardment and electroporation of intact tissue.  相似文献   

5.
苎麻耐镉品种差异及其筛选指标分析   总被引:3,自引:0,他引:3  
以营养液盆栽试验结合田间微区试验调查9个苎麻品种耐镉差异并筛选耐镉指标。结果表明,营养液盆栽试验中,不同镉处理下苎麻株高、单株叶片数、地上部干重和地下部干重差异显著,各性状具有较大的品种间差异。地上部干重与株高、叶片SPAD值和地下部干重均呈显著或极显著正相关,相关系数分别为0.95、0.82和0.85。田间微区试验中,地上部干重与株高、茎粗、皮厚均呈显著或极显著正相关,相关系数分别为0.86、0.72和0.76。分别对营养液盆栽试验和微区试验各指标耐镉指数的隶属函数值进行聚类分析,9个品种均被分为3类,结果基本一致。说明以营养液盆栽苎麻的株高、叶片SPAD值、地下部干重和地上部干重作为指标筛选苎麻耐镉品种是一条有效途径。  相似文献   

6.
植物源杀虫剂的研究进展   总被引:5,自引:1,他引:4  
植物源杀虫剂是当前研发化学杀虫剂替代品的热点。本文对植物源杀虫剂的优势与机遇、开发研究现状、主要的作用方式、作用机制等进行了综述,并展望了其发展前景。  相似文献   

7.
G. R. Mackay 《Euphytica》1973,22(3):495-499
Summary The frequency of sesquidiploid hybrids amongst the progeny of single turnip (B. campestris) plants following their isolation, in insect cages, with single rape (B. napus) plants confirms that the self in compatibility system of the former is sufficient to ensure interspecific hybridisation without resorting to hand pollination. The sesquidiploids performed favourably in a small scale yield trial and their possible production as alternatives to true rape is discussed.  相似文献   

8.
植物精油防治储粮害虫的研究进展   总被引:14,自引:4,他引:14  
化学农药长期大量使用导致的环境污染、害虫抗药性以及对人畜不安全等一系列问题越来越受到人们的关注,利用生物防治技术对储粮害虫进行控制日显重要。植物精油属于植物源农药,它是一类植物次生代谢物质,具有生物农药的优点。本文总结了近年来关于植物精油对仓库害虫防治方面的研究报道,主要包括毒杀、驱避、拒食和生长发育抑制等几个方面的内容,关于机理研究方面则相对较少。  相似文献   

9.
Sorghum is grown in the subtropics in north-eastern Australia, where production is risky due to limited planting opportunities and highly variable rainfall during the crop cycle. To improve grain yields of sorghum there, plant breeders have adopted the empirical approach of selecting directly for grain yield, because traits likely to confer improved adaptation have not been clearly defined. Even for readily-observed traits such as maturity type, no clear selection goal had been identified for this highly variable environment. This paper examined the use of isopopulations as a tool for defining traits for selection in plant breeding programs, and discussed the merits of this approach relative to other alternatives. Phenology of sorghum in north-eastern Australia was used as a case study. Isopopulations differing in maturity were developed from three populations of sorghum, and were grown in five contrasting locations. For stable grain yields, the best time to flowering was consistently about 1200 day-degrees using a base temperature of 7°C (or about 60 days to flowering for midsummer plantings in Central Queensland). This result was in accord with other direct experimental evidence, but contrasted with recent simulations reported in the literature, which suggested a longer crop duration was preferred. Our conclusions were that the crop model failed to extend growth duration in response to water stress, thereby increasing the yield expectation for a later flowering hybrid in a poor season. The simulations also assumed a full profile of soil water at planting in every season, which would have provided a different outcome from simulations in which conditions prior to planting were permitted to impact antecedent soil water. The strengths and weaknesses of experimental and simulation approaches were discussed, before concluding that the comprehensive evaluation of traits may best be accomplished by a combination of approaches: analysis of variety trial data, direct comparisons using isopopulations or isolines, and appropriate use of a validated crop model.  相似文献   

10.
了解永德县荔枝主栽品种‘桂味’与区试品种果实品质表现,为‘桂味’品质提升和品种改良提供建议。采集30个果园的‘桂味’和7个区试品种荔枝果实,测定分析果实品质,并结合品质加权分、经济效益指数对测试品种进行评分排序。调查花期授粉源和气温以分析‘桂味’焦核率低的原因。结果表明,永德县‘桂味’荔枝平均单果重、可溶性固形物含量和可食率分别为22.53 g、19.27%和76.61%,单果重和可溶性固形物含量优于广东大部分产区;焦核率仅为44.00%,低于广东大部分产区。经济效益指数评价结果显示,7个优新品种荔枝均优于‘桂味’,依据区试品种荔枝果实品质表现,除‘岭丰糯’外其他品种初步判定引种成功‘。桂味’与大核品种‘怀枝’等混种且花期相遇,推测花粉源和授粉期间长时间低温可能是当地‘桂味’大核化的原因之一,提高‘桂味’焦核率是提质增效的技术关键‘。无核荔’‘、贵妃红’‘、冰荔’‘、仙进奉’引种区试表现较为优异,适合作为永德县荔枝的改良品种。  相似文献   

11.
植物源杀虫剂是植物产生的次生代谢物质,因其具有特异的生物活性,因此为研究开发植物源杀虫剂提供了丰富的资源,是有机合成化学农药的替代品。本研究对植物源杀虫剂简史及现状、有效活性成分、作用方式等作了较为详细的综述,提出了植物源杀虫剂研发目前存在的问题及发展前景。本研究将为开发更多的植物源杀虫剂提供参考和借鉴。  相似文献   

12.
Summary Developed countries need to promote alternatives to crops produced in excess (such as cereals), and cultivation with limited environmental impact. Hemp (Cannabis sativa L.) is a potentially profitable crop, fitting into sustainable farming systems. Interest in new fibre crops is in fact increasing, to find alternatives to a high-input crop such as cotton, or to relieve the pressure of the paper industry on remaining natural forests. Besides, innovative applications are provided by hemp in renewable raw materials (oils from seeds and essential oils or secondary metabolites from inflorescences for food, cosmetic or pharmaceutical industry; straw and hurds for the building industry and for energy production). The development of more specialized hemp plants, needs a better understanding and control of metabolism. Since the renewed interest for this crop is increasing all over the world, it is important to update the knowledge on this crop, to understand whether it is a really sustainable, alternative and economically rewarding crop, and what contribution plant breeding, agronomical practice, and processing techniques are making, or could further make, to improve the relevant traits. The symposium Hemp: perspectives for advanced utilization, held in Bologna (Italy) on March 2004, was an opportunity to update the research carried out in different fields.  相似文献   

13.
植物提取物因其安全、绿色和高效等特点已成为目前替代抗生素的研究热点。植物提取物含有多种有效成分,具有多种生理活性,应用于不同水产动物效果不同。本文分别从诱食性、促生长、免疫增强、抗氧化应激和抗病原菌五个方面,综述了植物提取物在水产饲料中的最新研究进展,为开发环保型饲料添加剂提供理论参考。  相似文献   

14.
朱春江 《中国农学通报》2012,28(12):279-283
针对目前农业产业集群评价研究现状较少状况,尝试运用模糊数学方法对指标数据运用隶属度函数处理,以一级模糊综合评价向量作为神经网络评价模型的输入,再运用神经网络模型对农业产业集群进行评价,神经网络的非线性处理能力使农业产业集群评价更加科学化,并以连云港农业产业集群评价为例给出了实证研究。  相似文献   

15.
Due to the particularity of public projects, the evaluation of management patterns of public projects is an important aspect of performance evaluations of public sectors, and is the premise and foundation for improvement of decision - making management of projects. The objectives and contents of evaluation and selection rules of evaluation indexes were discussed briefly. The evaluation indexes system of management patterns of public projects is proposed. Applicable evaluation methods and the application bounds of the evaluation indexes system are put forward.  相似文献   

16.
ABSTRACT The purpose of this study is to analyze the effects of transportation investment on the Korean economy using the dynamic Computable General Equilibrium model. The result of the counterfactual analysis shows that infrastructure investment policy has the advantage of economic growth, but the disadvantage of price inflation. The elasticities of infrastructure investment with respect to GDP, export, private utility, and inflation depend on institutional restrictions on the domestic inflow of foreign capital and financing alternatives for infrastructure projects. The growth effect of transportation investment would be maximized if regulations on inflow of foreign capital to the private sector were lifted. On the other hand, the effect of transportation investment on inflation would be minimized if transportation investment expenditure were completely financed by tax revenues.  相似文献   

17.
Existing pipeline safety evaluation models commonly use the subjective methods such as the expert evaluation method, but the subjective consciousness has serious influence on the determination of index weight. Therefore, the match degree of the evaluation and the real condition is low and the evaluation result lacks of comprehensiveness. This paper determines the major evaluation index of long-distance oil-gas pipelines through the analysis of the goals and features of the safety evaluation. Fuzzy mathematics method is applied to build the comprehensive evaluation model of long-distance oil-gas pipelines and to analyze the key technology of the evaluation model. Variation coefficient method and analytic hierarchy process are comprehensively utilized to make a quantitative analysis of the criteria layer weight, and preferential relation matrix and fuzzy consistent matrix are established to determine the index layer weight. Finally, some examples are given to verify the feasibility and accuracy of the proposed model.  相似文献   

18.
Spatial planning aimed at multifunctional agriculture can be seen as a negotiation process on environmental, social and economic aspects of land use. Complexity arises due to the high number of stakeholders and due to the limited knowledge, which is often organized along disciplinary divides. This paper sets out from the premise that the role of agronomy in such land use planning processes can be strengthened by approaches that allow multi-objective and multi-scale evaluation of spatially explicit land use alternatives. We present an application of the explorative Landscape IMAGES framework, which employs the Differential Evolution optimization strategy and the concepts of Pareto optimality that are relatively easy to implement and to combine with spatially explicit indicator assessments. This technique yields a set of solutions, each representing a spatial configuration of hedgerows in a landscape along with the performance of the landscape in terms of Pareto rank and efficiency. The methodology was applied in a redesign of the structure of linear landscape elements in an agri-ecological zone in The Netherlands where 7 indicators representing ecological quality, landscape character and implementation costs were considered. The case study was developed in interaction with an NGO involved in landscape management planning and implementation.Spatial cohesion in the landscape was found to increase with larger total hedgerow length, but could also be improved without increasing the total length (and therefore costs of establishment and maintenance). Trade-offs existed with other objectives, since this change would involve replacing hedgerows currently positioned in the longitudinal direction (L) of the fields by hedgerows in the transversal direction (T). This change would compromise cultural heritage value as expressed in the L/T ratio, and it would require removal of mature hedgerows in some places and adding of new hedgerows elsewhere in the landscape, thereby increasing implementation costs.The approach was evaluated positively in terms of design validity, output validity and end-user validity. The role of the Landscape IMAGES framework in setting a research agenda to enhance the role of agronomy in multifunctional land use planning is discussed.  相似文献   

19.
Research Note     
In 1985, the people of the once tin­rich and prosperous Kinta Valley faced a desperate situation when the tin market collapsed. The nightmare was a result of cumulative effects — high cost of production, low yield of mines and extensive use of cheaper alternatives. But the negative effects on tin mining settlements were avoided due largely to Malaysia’s successful economic restructuring and the inflow of international capital in the manufacturing sector which has helped the local economy to recover. With tin mining disappearing from the Malaysian landscape, most of those still living in settlements previously highly dependent on tin have been able to find alternative livelihoods.  相似文献   

20.
The synthetic quantified evaluation for power quality is one of the gist to weigh excellent or inferior of the power quality, and this is propitious to realize the electricity-purchase principle of discussing the price according to quality and high quality high price, thereby serve as to build the equitable electric power market. This paper proposes to use the method of matter-element for power quality evaluation, and then build the model based on the method of matter-element. Considering the non-compatible feature between the single recognition and evaluation results as well as the complexity of the evaluation for power quality, a model is approached for the evaluation of the power quality by using the matter-element and extension set. Case results show that use the proposed model is objective and reasonable, with a special advantage when used in power quality evaluation.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号