油罐冬季不加热运行的热力计算

鄯善外运油库原油罐热力系统冬季运行期间暴露了两个问题。一是水击严惩,影响油罐的运行安全;二是油罐冬季非运行期间油温过高,造成能源浪费。为妥善解决这些问题,对油罐的保温性能进行了分析,同时对油罐的伴热系统进行了热力计算。计算结果对油罐冬季退出热力运行提供了理论依据。经济分析结果表明,油罐热力系统冬季退出运行后,原油输送成本降低,节能降耗效果显著。     

马铃薯种薯农场标准化栽培技术

利用高海拔地区的自然优势，采用农场标准化的生产模式，进行马铃薯种薯生产，提高了种薯质量，创新了栽培技术。     

无公害农产品生产开发的现状及发展对策

对我国无公害农产品生产现状进行了概述,指出江苏省目前还未能形成大规模产业化经营格局,但其生产开发已引起社会各界高度重视,其生产开发的相应对策主要包括:政府环保主管部门对排污企业加强管理以确保农业生态环境的合格标准;对农作物须科学施肥;农作物病虫害防治应采用综合防治的策略.     

滁州市安全农产品生产略论

当前,农产品的安全问题,情况令人担忧.生产安全农产品势在必行.如何搞好滁州市的安全农产品生产,本文提出四点建议.     

多哥糖联农场甘蔗生产上的问题与对策

本文叙述了多哥糖联甘蔗生产中存在的放弃甘蔗品种工作、新植蔗播种量单一、宿根蔗不松蔸、施肥量一刀切、肥料种类少、培土质量差、轻视病虫防治等问题 ,并针对这些问题提出了重视品种工作、因地确定播种量、宿根甘蔗松蔸、增加肥料种类、因土施肥、增高培土、实施病虫预防措施、喷洒有效药剂等切实可行的解决措施     

DNA imaging. Getting a feel for genetic variations

A team of researchers has come up with a novel atomic imaging microscope that may dramatically speed the task of linking genetic variants to diseases. The microscope is a modification of the popular atomic force microscope (AFM), which uses an ultrasharp tip to map surfaces of everything from computer chips to DNA at the atomic level. By using this molecule-sized tip, the researchers were able get their AFM to march down a strand of DNA and identify uniquely shaped reporter molecules engineered to tag the genetic variations.     

Spatial variation of technical efficiency of cereal production in China at the farm level

Rice, wheat and maize are the main staple food crops to ensure the food security in China with diversified climate condition, cropping system and environmental and socio-economic factors across provinces. Spatial variation of technical efficiency in farmers' field is helpful to understand the potential to improve farmers' yield given the inputs level and reduce the yield gap. The study is based on a large-scale farm household survey which covered 1 218 rice farmers, 3 566 wheat farmers and 2 111 maize farmers in the main producing areas. The results indicate that rice farmers are with very high technical efficiency level, nearly 0.9 on average, with little room to improve the efficiency of agricultural inputs. Similar results have been found in wheat and maize farmers' fields, although the technical efficiency levels are lower than that of rice farmers while still at a high level with obvious variation across regions. Farmers with higher yield level also achieve better technical efficiency in most locations. Both local environmental and socio-economic factors significantly affect farmers' technical efficiency. In the context of urbanization and economic development, improved and new agricultural technologies need to be prioritized and facilitated to improve cereal yield at farm level.     

保护地蔬菜生产推广中的问题分析--来自农户层次的访谈结果

本文利用问卷调查,深入了解和总结了农户层次对保护地蔬菜这样一种技术接受过程中的不同影响因素,反映了技术推广的复杂特点.