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区域创新系统具有开放性、自组织、非线性、动态性等特点.其演化的动力来自系统内各主体间的竞争与协同,所以用耗散结构理论和自组织理论分析区域自主创新的内涵,认识区域自主创新的形成机制,可以为区域自主创新活动提供理论依据. 相似文献
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胀压自紧式堵头 ,结构由螺母、压板、密封件、螺杆组成 (图 1) ,制作堵头所用金属选1Cr18Ni9Ti ,密封件材料为聚四氟乙烯 ,密封件外径应比所封铜管内径小 0 2~ 0 4mm ,壁厚应均匀。将胀压式堵头插入管内 ,拧紧螺母 2 ,使密封件变形胀紧管壁。调整螺母 2可调整密封件的变形量。可一次拧紧螺母 2 ,锁紧螺母 1,使堵头可以承受足够大的管内蒸汽压力。对于漏点在管子中间位置 ,可截去一段 ,分别封堵。将此堵头用于从瑞典Flakt公司引进FCLC型气垫干燥机的管型热交换器 ,效果很好。能耐受管内 180℃蒸汽温度及1 3MPa的压力 ,操作简捷 ,处理… 相似文献
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我厂1575纸机的φ3m 烘缸,在长期使用中表面接触到的ClO~(1-)、SO_4~(2-)、Ca~(2+),当气温波动时,次氯酸根、氯酸根、硫酸根就形成HClO、HCl、H_2SO_4、CaCl_2腐蚀介质。当表面磨损粗糙时,CaCl_2便附在其缸面上形成一层浆垢,从而进一步对缸面腐蚀直至不能应用。为此,1985年秋,我们采用喷涂技术修复缸面。选择喷涂材料时,我们从防腐角度出发选用了1Cr18Ni9Ti 作为喷涂材料,喷后缸表面硬度太低,刮刀一碰就有伤痕,因此不能投产使用,只好将涂层车掉。对1Cr18Ni9Ti与45钢进行比较,认为45钢的密度、硬度、导热性等物理性能均优于1Cr18Ni9Ti。故改用45钢再次喷涂,喷后使用两年又被腐蚀。 相似文献
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贵溪冶炼厂亚砷酸车间采用日本东予冶炼厂湿法提砷工艺。该工艺复杂 ,介质的腐蚀性很强。工艺设备多为搅拌槽 ,自车间投产以来 ,搅拌槽筒体材料相继使用过碳钢内衬PE、碳钢内衬橡胶及铬镍奥氏体不锈钢( 1Cr18Ni9Ti)。经过几年的使用 ,都出现过不同程度的腐蚀 ,主要现象有 :槽筒体焊缝多处剥离 ;焊缝及焊缝附近腐蚀严重 ;板材上局部有腐蚀点 ,甚至发生穿孔 ,密封的三角挡流板内板材穿孔更严重 ;内部支撑件的连接处脱焊等。1 腐蚀原因分析工作条件 :搅拌槽体内有四个密封的三角挡流板 ,每天作业2 0h。槽内蒸汽盘管加热 ;下部鼓风 (吹氧 ) ;… 相似文献
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为了减少焊接时产生的高温对热影响区韧性的影响,分别研究了焊接线能量、焊丝功率分配、焊接电压和焊丝间隔对温度场的影响。基于Visual-Environment有限元软件,利用双椭球热源模型,对30 mm厚EH420船板钢三丝埋弧焊接温度场进行了数值模拟。结果表明:1)当线能量从150.26 kJ/cm降低到104.72 kJ/cm时,粗晶区峰值温度降低了322 ℃;2)当线能量相同时,前丝功率占比从25.00%上升到41.67%,且中丝功率占比不变的情况下,粗晶区峰值温度降低了56.79 ℃;3)提高焊接电压后,粗晶区峰值温度、熔深和熔宽变化较小;4)焊丝间隔从20 mm增加到45 mm,熔池长度增大了50 mm,并在焊丝间隔40 mm之后出现由单熔池向双熔池转变的现象,粗晶区峰值温度呈现先增大后减小的趋势,焊丝间隔在35 mm达到最高温度1 183.62 ℃;5)从拟合结果得出,在焊接30 mm厚的EH420船板钢“Y”型坡口时,线能量应采用174.54 kJ/cm,在此线能量下前、中、后丝的功率占比采用15∶11∶7且焊丝间隔为20~30 mm,能够有效避免出现焊接缺陷。研究结果既可以保证焊接质量,又可以大幅提高焊接效率,为企业降本增效提供新方法。 相似文献
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集群风险自组织理论建构的探索式案例研究 总被引:3,自引:0,他引:3
集群风险已经成为一种普遍的经济现象,受到理论界的广泛关注,集群风险自组织则是其核心内涵的反映。根据协同学理论的分析框架及探索式多案例的研究设计,本文通过对三个企业集群样本的逐一研究剖析发现:集群风险自组织是一个内在结构演化的过程,由焦点企业、网络能力、网络结构三者相互作用而阶段性表征;在层次性、非线性和协同性三者协同演化下,风险阶段性地打破了集群平衡态,从而形成集群风险自组织间断非平衡性的特征。论文建构了集群风险自组织理论机制,对集群风险治理的实践具有一定启示意义。 相似文献
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高道春 《石油化工技术经济》2010,26(2):45-48
通过1H固体核磁共振(NMR)技术和长期力学性能测试研究了基于Cr系催化剂、分子量呈单峰分布以及基于Z—N催化剂、分子量呈双峰分布的两种PE100级管材料的构效关系。依据部分结晶聚乙烯的相结构三组分模型,分析了单、双峰分子量分布PE管材料的反应器粉料、自然色造粒料、炭黑填充粒料以及热模压片料的相结构特征。结果表明:单、双峰PE100管材料三组分相组成随粒子状态的变化趋势一致,在相同的粒子状态下,单峰聚乙烯管材料均表现出较低的固相含量,较高的界面区和无定形区含量,其晶区厚度显著低于相对应的双峰管材树脂,而界面区和无定形区含量则相差不明显,由此引起了其NMR长周期的显著降低。 相似文献
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通过大量试验探索了提高墙地砖陶瓷模具使用寿命的途径。试验表明,用双金属材料完全可以取代 Cr12MoV 钢来制造优质模具,其使用寿命为Cr12MoV 钢的两倍。 相似文献
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本文分析了3Cr2W8V 钢制气门模具的主要失效形式。型腔不耐磨及微量塑性变形是模具使用寿命低的根本原因,在保证基体强度和韧性的条件下,采用方法简便的盐浴软氮化处理,可有效地提高耐磨性,其使用寿命提高1.1~1.9倍。本文还分析了此种方法处理后的性能、特点及该方法的应用前景。 相似文献
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The paper contains a report of a test of Cooper's NewProd model for predicting success and failure of product development projects. Based on Canadian data, the model has been shown to make predictions which are 84% correct. Having reservations on the reliability and validity of the model on theoretical grounds, we set out to test it using data collected in the Netherlands.
Following Cooper's methodology, we selected 19 projects, which had already been marketed and of which 9 were clearcut successes and 10 clearcut failures. We also studied 9 additional projects, which had not yet been commercialised, as the basis for a future a priori test. The projects were given a product score according to Cooper's criteria, and predictions compared with the actual experience. Eightyfour percent were correctly classified, as in Cooper's work. From a practical point of view however the variance was too large to allow the predictions from NewProd to be used with confidence to predict outcomes unless they are clearcut.
We believe that the drawback of the methodology is that the product score is a simple combination of the various factors involved. No allowance is made for the possibility that one factor alone might be responsible for failure. We have therefore introduced the concept of a threshold value for each factor. A project for which any factor falls below this value will be deemed a failure. Based on a very limited sample of 19 cases an improvement of reliability was made to 95% of 18 out of 19 products correctly classified. The NewProd concept so modified is being applied to the sample of 9 as yet uncompleted projects, and its predictions will eventually be compared with actual outcomes. 相似文献
Following Cooper's methodology, we selected 19 projects, which had already been marketed and of which 9 were clearcut successes and 10 clearcut failures. We also studied 9 additional projects, which had not yet been commercialised, as the basis for a future a priori test. The projects were given a product score according to Cooper's criteria, and predictions compared with the actual experience. Eightyfour percent were correctly classified, as in Cooper's work. From a practical point of view however the variance was too large to allow the predictions from NewProd to be used with confidence to predict outcomes unless they are clearcut.
We believe that the drawback of the methodology is that the product score is a simple combination of the various factors involved. No allowance is made for the possibility that one factor alone might be responsible for failure. We have therefore introduced the concept of a threshold value for each factor. A project for which any factor falls below this value will be deemed a failure. Based on a very limited sample of 19 cases an improvement of reliability was made to 95% of 18 out of 19 products correctly classified. The NewProd concept so modified is being applied to the sample of 9 as yet uncompleted projects, and its predictions will eventually be compared with actual outcomes. 相似文献
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DS18B20与单片机的接口及编程技术 总被引:1,自引:0,他引:1
介绍了DS18B20的性能、内部结构及优越性,并详述了单线数字温度传感器DS18B20与单片机的接口技术以及在温度测量中的硬件和软件设计,最后以一个程序实例进行了说明。 相似文献
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由于对土壤环境的分析与研究存在着一定的不确定性,使用模糊数学的评价方法对于不定量的研究具备比较精确和细化的作用,能够为涉及土壤重金属污染等具有相对较模糊和不能量化特征的学科提供较为精确的研究方法。通过对韶关市大宝山重金属矿区的矿山开发和土壤重金属污染现状采取实地调查和取样分析,在大宝山矿区的上、下游以所选取5个区域土壤的Cd,Cr,Pb,Cu,Ni,Zn等6种重金属元素的含量作为样本数据,结合模糊数学理论在重金属污染评价方面的应用,建立模糊评价模型进行分析,其结果表明矿区下游区域土壤的重金属污染主要致灾污染因子为矿山开采所导致的重金属污染。并且,凉桥、水楼下、石柱下、上坝和下坝村等大宝山下游区域土壤中的Cd,Cu,Pb等重金属元素含量均已超过国家土壤质量标准(GB 15618-1995)规定的土壤二级标准值。 相似文献
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Personality and other attributes,qualities, abilities and opinions of some ‘A’ level design students
John Tyers 《International Journal of Technology and Design Education》1991,1(3):159-170
Many claims have been made of a subjective nature that some students studying A level Design develop certain personal qualities and attributes not found in some students who study other academic A levels. The research describes attempts to quantify these claims and as a result provides a firmer basis for the understanding of the effects on students of studying design. 相似文献