DEVELOPMENT AND EXPERIMENTAL ANALYSIS OF HYDRAULIC LOCK OF THE THINNEST COAL SEAM SHEARER

The structure and work theory of a new type of hydraulic lock of the thinnest coal seam shearer is described in this paper. Its performance tests have been done the test results show that the performance of hydraulic lock is satisfactory and can be fit for the needs of locking and floating of the cutting drum of the thinnest coal seam shearer     

THE PERFORMANCE ANALYSIS FOR THE HYDRAULIC SERVO-SYSTEM OF HAULAGE PARTY FOR SGW-150 SHEARER WITH CONSTANT POWER SPEED GOVERING

The mechanization of mining thinnest coal seam is a key program in the 7th five-year plan in Sichaan province, It is sponsored by The Scientific and Technieal Commission of Sichuan province. In this paper, the dynamic performance for the hydraulie servo-system of haulage party for SGW-150 shearer with coustant-power speed governing is analysed. It shows that the system designed by us is stability and reasonable for SGW-150 shearer.     

OPTIMIZATION DESIGN OF THE HYDRAULIC OPERATED CHECK VALVE OF A THINNEST COAL SEAM SHEARER

On the basises of optimization theory and cross-experiment analysis, the mate scheme of structural parameters of the hydraulic operated check valve having the best performances is deduced in this paper,the notability of the structural parameters affecting the valve's performances is discussed,and the main-minor relation between factors is found.     

THE STUDY OF THE RELATION BETWEEN COAL-GAS OUTBURST AND PHYSIC AND MECHANIC PROPERTIES OF COAL SEAM IN A COAL MINE

The experimental study of physic and mechanic properties of coal seam in a coal mine is presented, and the relation between coal-gas outburst and the strength, the elastic modulus, as well as the deformation property of coal seam is analysed on the basis of the experimental results.     

新型粮食包装袋的性能研究与分析

研究了花生在不同结构包装袋内储存过程中的微环境变化,包括气体成分、温湿度、花生含水量以及包装袋含水量.结果可知,覆膜包装袋袋内的相对湿度受外界环境影响较小,说明覆膜包装袋能更好地控制袋内的相对湿度,减少外界环境的影响.储存高含水量花生的覆膜包装袋内的微环境发生了明显变化,实验结束时,其氧气浓度下降为9.4％,二氧化碳浓度则上升到8.9％.说明覆膜包装袋能够在袋内营造一个低氧气浓度、低相对湿度和高二氧化碳浓度的微环境.在温度方面,由于材料的隔热性能有限,对袋体内部温度的影响不大.因此,覆膜包装袋对于控制高含水量花生呼吸强度、延长存储时间有一定作用.     

粮食产后服务中心信息化体系构建

粮食产后服务中心作为粮食产后服务体系的核心,急农所急,为农分忧,主动便农惠农,积极承担社会服务职能,积极推动了农村经济发展。但是目前,粮食产后服务中心尚没有建立完善的信息化体系,只有个别区域的粮食产后服务中心建立了"粮食银行"信息管理系统,用于管理农民代储、代加工、代售的粮食。基于这种情况,本文在分析粮食产后服务中心服务职能的基础之上,构建了完整的粮食产后服务中心信息化体系,为粮食产后服务中心的发展提供技术支撑。     

ON THE PROBLEM OF SWITCHING CONDITIONS FOR A KIND OF MINIMUM-TIME CONTROL SYSTEMS

The paper provides a detailed study of switching conditions of minimum-time control systems based on application in engineering. By analysis in theory and experiment, the authors deduce a set of switching conditions with state and control variabes inequality constraints, the variations of system parameters and the time-delay of computer in real time control. As an example, a DC motor speed control system is considered. By digital simulation and physical experiments,these conditions proved to be correct. The method in this paper is also suitable for other control systems using compound control algorithm.     

我国粮食物流体系建设探究

粮食物流体系是粮食商品实体运动的依托和保证,也是粮食流通发展水平的重要体现。加强粮食物流体系建设是降低粮食物流成本、提高物流效率的需要,也是粮食商品流通通畅运行和进一步发展的客观要求。本文对我国粮食物流体系的建设情况进行了分析,指出了当前粮食物流体系建设中存在的主要问题,并就如何建设和完善粮食物流体系提出了具体的设想。意在对我国粮食物流的科学运作和管理水平的提高起到促进作用。     

拱板仓屋面喷水储粮安全度夏效果研究

针对拱板仓储粮度夏粮温偏高、分层明显和温差较大的特点，利用自来水自动循环装置对仓顶屋面进行喷水降温，最大限度地减少了盛夏仓顶曝晒后的积热，缩小了仓顶与粮堆之间的温差，延缓了粮温的上升速度，从而有效地改善了储粮在盛夏的高温环境，抑制了害虫的生长繁殖和粮食品质的陈化，是拱板仓储粮安全度夏的有效方法。     

A MODLE OF SYSTEM DYNAMIC FOR URBAN LAND PLANNING

This thesis uses the theory and method of the system dynamics to analyze the characteristics of the urban land planning system and set up the urban land planning system dynamic model, The model could describe the influence and request of factors of the society. economy and environment to the urban planning by using the system, the quantitative and the dynamic methods. By adjusting the parameter and repeating model imitation, the model could provide the possibility of realizing the present land planning and provide the quantitative analysis method for the planning department to make or adjust the land planning, and assist the government department to make decisions.     

ZC—4型微机测温测湿系统在粮情检测中的应用

文章报导了ZC—4型微机测温测湿系统在储粮检测中的应用情况。结果表明:该系统重复测量稳定性好,能准确有效地反映粮堆内部不同部位的温度变化及仓内外相对湿度的变化情况;测量快速、方便,储量大,节约费用,具有明显的社会效益和经济效益。     

A PRIMARY STUDY ON A LIFTING PERFORMANCE CURVE ADAPTED FOR THE MECHANICAL LOAD MOMENT LIMITER

The condition when forces are applied to load mechnical mornent limiter of tow-er cranes is analysed and disctissed in this paper.A lifting performance curve adapted for the me-chanical load moment limiter is also obtained.And finally,the curve drawing method is explainedthrough the practical example.     

A METHOD OF SYSTEM IDENTIFICATION AND MODEL REDUCTION BASED ON TIME-DOMAIN RESPONSE OF A DYNAMIC SYSTEM

This paper combines model reduction with system identification by means of time-domain function approximation, and presents a new time domain method of direct identification of linear reduced model and model reduction, and demonstrates existence theorem of its solution and criterion of order determination. Simulation tests show that the method is simple, accurate with few data requirement.     

氮肥对棉花根系载铃量的效应研究

本文研究了不同氮肥水平条件下棉花根系生理活性的变化与根系载铃量的特点。结果表明,氮肥能提高棉花根系干重和根系的生理活性,不同氮肥水平下又以N150kg/hm~2的根系生理活性较高;0～15cm耕层的根系为根系干重和根系生理活性的活跃层,其根干重占总干重的90％以上,根系生理活性占总量的70％～90％;不同氮肥水平下,也以N150kg/hm~2单株成铃较多;根系载铃量、根系载荷能力、根活性载铃量、根活性载荷能力也以N150kg/hm~2处理稍高,而且全生育期中较为平衡。     

世界储粮生态系统网络体系的研究设想

为了进一步促进中、加科技研究合作,在中国、加拿大近几十年粮堆生态系统研究成就的基础上,参考了我国7000-10000年以来的先民储粮技术经验,特别是近60年来我国的粮食系统科技创新进展;参考了世界一些粮食储藏技术比较发达国家取得的研究成果,系统分析了建设世界储粮生态系统网络体系的必要性,清晰地提出了网络体系的研究设想及相关研究课题。     

A STUDY ON THE EVALUATION OF THE AROMATIC1TY AND CONDENSATIONAL EDGREE OF COAL MACROMOLECULAR STRUCTURE

The aromaticity and condensational degree of coal macromloecular structure are studied through the correction for the presence of aliphatic side chains and hetero-atoms in coal rnacromolecule, which enables the coal structure to be considered as the purely hydro-aromatic hydrocarbon. The results agree with the properties of coal rnareomolecule.     

A NERUAL NETWORK FOR THE ADAPTIVE CONTROL OF A 2 ORDER NONLINEAR SYSTEM

This paper presents a new method of self tuning adaptive control which adopts a neural network to identify the characteristics of a second order nonlinear system, which is in turn applied to adaptive control. The simulations show that the method has good capability of sduty and adaptation.     

二季作地区马铃薯脱毒种薯繁育体系的研究

天津处于我国马铃薯种性严重退化的二季作地区.针对我市马铃薯病毒病,结合二季作地区留种技术,采用早熟优种红纹白、丰收白进行脱毒种薯生产.试验中将塑料大棚生产技术,地膜覆盖技术用于脱毒种薯生产,达到了早收、防蚜目的.并结合二季作地区秋播留种,完成了天津市三年六代的马铃薯脱毒种薯的繁育体系.各级种薯达到了国内暂行规定标准.     

黄曲霉毒素B1荧光定量快速检测试纸卡和仪器技术性能优化研究

基于时间分辨荧光微球制备的黄曲霉毒素B₁荧光定量快速检测试纸卡,通过两线及三线试纸卡灵敏度与重复性的对比,筛选出效果更优的三线试纸卡,并对三线试纸卡不同性能要求进行检测验证。结果表明,黄曲霉毒素B₁三线试纸卡检出限与定量限符合要求,准确度、重复性、稳定性等均达到更优的效果,更能满足检测需求。