三元商品母猪繁殖效率劣势分析与对策

在非洲猪瘟影响下,养殖企业(户)选择三元留种扩群也是一种无奈之举,本文针对三元母猪在繁育性能上存在的问题进行分析,并提出相应对策,旨在解决当前养猪行业的困惑。     

三元猪简介及饲养技术要点

近几年，我省养猪总体水平不断提高，品种结构不断调整，但在农村广泛饲养的多为血统不清的土杂猪。这类猪生长慢、饲料转化率低、价低滞销，不适合市场需求。目前，我省三元商品猪占总出栏猪的比例不足 30％，主要原因是一些养猪户没有认识到饲养三元商品猪的好处，没有掌握良种猪的饲养技术。 什么是三元商品猪 ?三元商品猪在目前有两种。一是外三元 (即洋三元 )，一种是内三元 (即土三元 )。外三元是杜洛克公猪与长大杂交母猪 (或大长杂交母猪 )的后代，饲养成为商品猪。其优点是生长快，饲料转化率高。目前，用世界最先进的“双肌臀”种…     

离散群的三元数组

讨论了二元生成Mǒbius子群(f，g)的离散性、初等性与三元数组(β(f)，β(g)，γ(f，g))的关系，得到了集合E的一些性质，给出了集合D∩E1的具体刻划，并利用代数方法证明了集合E和D∪E是C^3上的闭集．     

三元企业经济效益综合评价及对策

本文采用定性与定量相结合的分析方法,对北京市三元食品股份有限公司经济效益进行综合评价。利用因子分析法构建适合三元企业的经济效益评价体系,对三元企业发展能力进行研究。研究表明北京三元股份有限公司总体发展态势良好,具有较强的经济效益,是一个非常有发展前景的企业。但是三元企业在经营过程中也存在很多问题,如企业盈利能力差、偿债能力差等,本文提出了引进核心技术、加强资金管理等建议,以促进北京三元企业提高经济效益。     

浙江省粮经饲三元种植结构发展对策

本文从宏观和微观两个层次上论述了种植业粮，经，饲三元结构的基本概念，提出了浙江省发展种植业三元结构的布局构想和若干对策。     

养猪多些“土三元”少点“洋三元”

饲养三元杂交猪已渐成各地农户的共识。要说“三元”,这里有“洋三元”和“土三元”之分。“洋三元”如用美国的杜洛克同加拿大或英国的大约克杂交产生的二元母猪,再跟丹麦的长白作父本交配生出的三元猪。“土三元”如江苏省农科院葛云山教授采用本地的新淮猪作母本跟日本...     

三元猪和宁乡猪血液学参数比较研究

本研究分别采用全血细胞计数分析仪、全自动血液生化分析仪和γ-计数仪测定了三元肥育猪和宁乡肥育猪血常规、血清生化参数和激素含量常值,以供相关研究参考.结果表明,宁乡猪外周血白细胞总数、淋巴细胞计数、红细胞体积分布宽度和血小板分布宽度均显著低于三元猪(P<0.05),平均红细胞血红蛋白、平均红细胞血红蛋白浓度、血小板计数和血小板比积均显著高于三元猪(P<0.05);宁乡猪血清总蛋白、氨和葡萄糖含量显著低于三元猪(P<0.05),甘油三酯和甲状腺素T3含量显著高于三元猪(P<0.05).上述结果表明,两个品系猪的多数血常规和血清生化参数及激素含量存在显著差异.     

区域森林资源系统的“三元论”

从现代系统科学的整体论和发展论出发,提出区域森林资源系统的“三元论”并从区域森林资源系统的结构,功能和属性３个方面,将“三元论”作进一步的细化和展开。     

家蚕新品种“野三元”在云南的繁育及试养初报

家蚕新品种"野三元",是中国农科院蚕业研究所吴阳春等人将抗逆性强的野桑蚕与多丝量家蚕品种远缘复合杂交,选育出的强健性多丝量蚕品种。试验设计了新品种"野三元"的繁育对比试验、试验室鉴定对比试验、丝质对比调查等。试验结果表明,与对照种"菁松×皓月"相比,"野三元"具有食性优、繁育系数高、抗逆性强、产茧量高、茧丝质优良等特点,适宜引进云南蚕区全年饲养。     

三元经济结构与21世纪高校人才培养的素质要求

本文第一次提出了三元经济结构的概念，认为中国等发展中国家在２１世纪的一段较长时间处于三元经济结构时期。文中论述了三元经济结构的特征及其高校人才培养的目标，并阐述了在２１世纪三无经济结构下高校人才培养的素质能力要求     

330MW循环流化床机组CCS控制系统分析与应用

股市和债市的波动相关结构是研究金融市场信息流动、风险传递的重要内容.利用拓展的Copula模型——门限混合Copula模型,并结合EM算法等实证检验了我国股市和债市的关联特征.结果表明：两市波动关联性的不同分歧很大程度是注重对样本区间内整体关联性的检验, 忽视了不同阶段与市场波动的特定关系;同时新的Copula模型捕捉到了股市和债市波动的门限效应、非对称性及非线性等特点;两市相关结构频繁变动进一步说明金融资源配置效率偏低.     

黄瓜穴盘育苗三合一基质的筛选

将麦秸、土和牛粪以不同比例配成三合一基质 ,进行黄瓜穴盘育苗 ,均能形成紧实的塞子苗 ,其中以 6∶1∶3(麦秸∶土∶牛粪 )比例配成的基质最适合黄瓜幼苗生长 ,并且形成的塞子容重小 ,育苗程序简便、成本低廉 ,适宜于在广大地区推广应用。以这种三合一复合基质在 72孔穴盘上培育黄瓜苗 ,形成塞子苗的初始苗龄为第 2片真叶初展期。     

遥控自动立木整枝机运动控制系统

正确的控制逻辑是自动立木整枝机运动控制系统的关键技术.该文根据作业要求,研制了基于复杂可编程逻辑器件的自动立木整枝机运动控制系统.该系统采用自制的新型电动机位置动态检测装置,通过复杂数字逻辑运算及相应的闭环控制驱动电路,实现对人工林自动立木整枝机控制信号的分组、实时控制.该运动控制系统设计合理、控制逻辑准确,已成功应用于BSR Z23 001A人工林自动立木整枝机,工作可靠,使用效果良好.      

Fuzzy logic control of a multispectral imaging sensor for in-field plant sensing

The development of an in-field plant sensing system for a site-specific application can protect the environment from excessive chemicals and save management cost while maintaining productivity. A multi-spectral imaging sensor has been introduced and widely used for in-field plant sensing. In order for a robust performance of the spectral imaging sensor under changes in ambient illumination, image quality must be maintained for proper spectral image analysis. Image formation that is affected by camera parameters was identified, and a controller was developed to compensate varying image intensity and to obtain the desired image quality. A fuzzy logic control algorithm was applied to automatically adjust the camera exposure and gain to control image brightness within a targeted gray level. Slow convergence and oscillation were regulated by dynamic membership functions with different weights in each image channel. Images affected by illumination disturbance quickly converged into a desired brightness image within a maximum of five iterations over the entire range of camera gains in all three spectral image channels. An application of in-field plant sensing using the fuzzy logic image controller was evaluated on corn crops for nitrogen detection. The normalized spectral response of the sensor was inversely correlated to a chlorophyll meter with −0.93 and −0.88 in red and green channels, respectively. The development of an image quality controller using fuzzy logic enhanced the reliable performance of the in-field plant sensing system.     

棉花红铃虫管理专家系统及其实现

棉花红铃虫管理专家系统是一个集预测、诊断与咨询于一体的复杂系统,可直接指导农民生产实践.该专家系统将数学模型、历史数据资料和专家实践经验知识融为一体,采用PROLOG与C语言的接口.知识库知识采用带有变量的知识表示.系统由数据资料管理模块、知识库、模型库、推理机、知识获取模块、解释机构和人机接口所组成.经实践验证预测害虫发生准确率达90％以上.     

我国农村土地经营权制度的发展困境和路径研究

土地经营权是“三权分置”政策施行下独立出来的一个全新权能概念,但其与土地所有权、土地承包权仍有着密不可分的联系。土地产权理论框架下的土地经营权制度具有深厚的理论背景、清晰的发展脉络和具体的现实困境,体现出理论逻辑、历史逻辑和实践逻辑的统一。当前“三权分置”背景下农村土地流转进程发展迅速,然而土地经营权本身还存在着概念和法律界定上的理论难题,在流转过程中也存在土地流转不规范、承包农户的土地经营权受侵害、土地所有权承包权受侵害和配套政策设施不完善等现实困境。发展和完善土地经营权制度,确保土地经营权流转机制畅通,需要加强制度设计和法律规范,增强土地流转配套服务与管理,从而推动“三权分置”政策扎实落地。     

试论消除户籍歧视的三种制度

建立在“城乡分治”基础上的二元户籍制度歧视,使农民工的权益受到严重侵害。户籍制度虽经多次改革但收效甚微。要消除户籍歧视,须从农民工就业前、就业中、就业结果等三个方面着手来建立相应的三种制度,而每种制度又含有若干项可操作性的具体制度安排。     

The catalytic role of the active site aspartic acid in serine proteases

The role of the aspartic acid residue in the serine protease catalytic triad Asp, His, and Ser has been tested by replacing Asp102 of trypsin with Asn by site-directed mutagenesis. The naturally occurring and mutant enzymes were produced in a heterologous expression system, purified to homogeneity, and characterized. At neutral pH the mutant enzyme activity with an ester substrate and with the Ser195-specific reagent diisopropylfluorophosphate is approximately 10(4) times less than that of the unmodified enzyme. In contrast to the dramatic loss in reactivity of Ser195, the mutant trypsin reacts with the His57-specific reagent, tosyl-L-lysine chloromethylketone, only five times less efficiently than the unmodified enzyme. Thus, the ability of His57 to react with this affinity label is not severely compromised. The catalytic activity of the mutant enzyme increases with increasing pH so that at pH 10.2 the kcat is 6 percent that of trypsin. Kinetic analysis of this novel activity suggests this is due in part to participation of either a titratable base or of hydroxide ion in the catalytic mechanism. By demonstrating the importance of the aspartate residue in catalysis, especially at physiological pH, these experiments provide a rationalization for the evolutionary conservation of the catalytic triad.     

库鄯输油管道消防自控系统的改进

对油库而言,消防系统直接关系到输油生产的安全。针对库鄯输油管道站场消防系统存在的问题,提出了几条技术革新方案,利用可编程控制器的可扩展性和灵活性对几个逻辑功能进行改造,加强和完善了系统的控制功能。     

A web-based intelligent disease-diagnosis system using a new fuzzy-logic based approach for drawing the inferences in crops

This paper suggests a new approach for providing intelligence in the system for diagnosis of diseases of the oilseed-crops. It reports the development of a web-based intelligent disease diagnosis system (WIDDS). The WIDDS is based on a new fuzzy logic approach. The approach is based on use of a rule-promotion methodology. This approach enables the drawing of inferences with the enhanced intelligence. The WIDDS also incorporates new features that improve the presently existing expert systems. The new features are (i) object-oriented (O-O) inference model, (ii) dynamic knowledge base creation strategy. The dynamically promoted rules are derived from those diagnosis sessions, which resulted in successful decisions. This enables more efficient decision-making in the future sessions, (iii) audio-visual-graphical user interface using text-to-speech (TTS) conversion tools. The WIDDS results in decreasing not only the number of interactive question-answer sessions with the clients but also leads to acceptable diagnosis. Further, the inferences are drawn faster compared to the traditional approach, which is the expert based reasoning method. The suggested WIDDS, which is based on rule-promotion approach, has been tested for three oilseeds crops - soybean, groundnut and rapeseed-mustard.