Two Degree B-spline Curve Through Control Points

The construction of curve segments passing through the given data points is very important in CAD. The form and the base of B-spline curve have been improved. The new curve is through the control points, the shape of this curve is loud changed along with control points moving and need not reverse calculating, so the shape of curve charge quickly along with control points moving and can satisfy the precision. It can be applied to the numerical control and CAD, etc.     

北京梅花引种与梅花文化欣赏

北京对于梅花引种驯化的记载大抵始于元朝,因此历代各有累进。当代陈俊愉先生自1957年矢志引梅北上至今,北京已成规模花事,创造了梅花引种历史的里程碑,改变了此前北京人多是听说或通过绘画、摄影作品而获得感知的尴尬。北京引种梅花的规模成功为促进梅花成为双国花之一奠定了坚实的物质基础,也为北京梅花文化的欣赏提供了现实条件。梅花文化欣赏是中华民族一种比较特殊的花卉文化现象,源远流长、丰富多彩且影响深远。作为中华民族重要的精神文明载体,从古至今梅花文化欣赏的方式不胜枚举。自2003年以来,笔者有幸在北京梅花引种过程中不断体会梅花文化欣赏之魅力,今尝试归纳赏梅六诀,即花早、香幽、姿美、色繁、韵胜、格高,意在为梅花文化增添心香一瓣。     

数字雹雨分测仪的研制及应用分析

以雹雨测定为研究对象,提出了一种全新的数字雹雨分测仪测定方式,针对这种仪器的研制关键问题做出了详细分析,并结合西藏地区实测结果验证了数字雹雨分测仪的应用优势,旨在于引起相关工作人员的特别关注与重视。     

提高仔猪成活率的技术要点和管理方法

随着社会经济的发展,畜牧养殖已经成为人们一种重要的收入方式,规模化的生猪养殖更是成为一种普遍的经营手段.但是在养殖的过程中,由于仔猪的抵抗力等身体机能都不是很健全,极容易造成死亡,给养殖场造成巨大的经济损失.主要就提高仔猪成活率的技术要点和管理方法进行研究,为生猪养殖提供一些可行性的建议.     

青枣栽培过程中的病虫害防治技术探析

从笔者所在地区青枣病虫害发生的实际情况出发,结合实际工作经验,主要针对部分影响青枣生长的典型病虫害的发生和防治技术进行了探讨。     

家蚕病害防治技术要点解析

改革开放以后,中国的丝绸工业得到了进一步的发展,并且其产量跃居世界第一位,在世界经济结构调整的背景下,国际丝绸贸易格局发生了极大的变化,中国也正逐步成为世界丝绸生产的中心。而蚕桑的生产是丝绸工业正常运行发展的基础,所以我们对其的清洁以及质量忽视不得,因为家蚕一旦受到病害,是很难通过治愈而好转的,所以我们应在家蚕完好无病的情况下加强预防工作,如果发现有病害现象,要及时寻找病原,及时采取有效的防治措施,避免病害的蔓延。     

甜菜夜蛾的抗寒力研究

抗寒力的强弱决定了甜菜夜蛾的分布范围及越冬存活情况,并直接影响下一代的种群数量.通过测定甜菜夜蛾三个地理种群(河北隆尧、湖南衡阳和江苏南京)的过冷却点和结冰点及田间埋蛹越冬试验,以明确甜菜夜蛾的抗寒能力.研究结果表明,在各虫态中甜菜夜蛾蛹的过冷却点最低(-16.61～-15.18 ℃),其次为成虫、卵和幼虫.蛹的过冷却现象也最明显,因而蛹是其最适宜越冬的虫态.三个地理种群中,以湖南衡阳的抗寒能力最强,其次为河北隆尧和江苏南京.在2001和2002连续两年的田间埋蛹越冬试验表明,甜菜夜蛾的越冬死亡率均为100%.分析南京多年的冬季气温,表明某些年份甜菜夜蛾不大可能在南京越冬.因此甜菜夜蛾的常年越冬区范围应在南京以南的区域.     

豆制品煮浆工艺要点概述

豆制品加工工艺是不可逆工艺,所以每一个工艺环节的控制都会直接或间接影响到后续工艺环节和最终产品品质,主要论述了豆制品煮浆工艺的内容及要点,以及实际煮浆过程中的注意事项。     

Ecologically Sustainable Exploitation Rates—A multispecies approach for fisheries management

Fisheries management is slowly evolving from its traditional single‐species focus to a more holistic ecosystem‐based approach. Yet, limits for exploitation are almost always set based on single‐species models, treating species as isolated entities. This is problematic since the sustainability of a fishery hinges on its effects on the exploited community as a whole. Here, we develop a novel analytical approach of estimating exploitation rates that are sustainable with respect to the state of whole fish communities. Our approach simultaneously addresses species interactions, environmental covariates and natural variability of population sizes, yet it is framed around a simple and accessible objective. We derive Ecologically Sustainable Exploitation Rates, that is exploitation rates associated with a maximum acceptable probability (determined by management) that any interacting species decreases to an unacceptably low population size. Using models fitted to an exploited fish community, we show how accounting for species interactions constrains the possibilities for ecologically sustainable exploitation. The conventional omission of species interactions may thus result in overestimated exploitation limits. Moreover, our application rendered a counterintuitive result: it suggests that the exploitation of one species should increase, as compared to mean historical levels, for the purpose of conservation of the community as a whole. Such insights could impossibly be gained using single‐species approaches, illustrating the need to adopt multispecies models in fisheries management. Analytical derivation of Ecologically Sustainable Exploitation Rates offers a mean to do so.     

生食牡蛎HACCP计划的语义建模及可视化应用

为有效保障危害分析及关键控制点(HACCP)计划国家标准的可执行性,以国标中的生食牡蛎加工HACCP计划的语义表达为研究对象,提出生食牡蛎HACCP计划的知识可视化应用模型(HVEM),对HACPP计划进行结构和数据两方面的语义理解,从动态和静态两个角度进行知识提取,实现活牡蛎接收、干法冷藏、牡蛎肉储存等关键控制点(CCP)、监控以及验证、纠偏的实体、联系知识表达,构建HACCP计划知识体系,结合图数据库实现知识储存、可视化,并给出一个基于HVEM模型的HACCP质量溯源应用测试。结果表明,HACCP计划的知识可视化应用模型能较为系统地实现生食牡蛎HACCP计划的知识理解、知识表达、知识存储和可视化应用。