生活的启迪

生活常常给人以多种多样的启迪,日积月累,就像一把闪光的钥匙,开启智慧的大门。生活的启迪常常是一掠而过。稍纵即逝,犹如江河里的浪花,黑夜中的闪电;生活的启迪忽隐忽现,时断时续,好像秋雨一般密集,山风一般连绵。要捕捉它,却不那么容易,惟有热爱生活     

西部，那些隐藏的财富

你想象过吗？全中国最大的价值集散地,已经不再是山西的煤田,不是山东的金矿,不是东北的铁矿石,而是在新疆天山,在青藏高原的冈底斯山,在云南的哀牢山,在陕西的金堆城,在贵州的开阳,在青海湖。在想象力能都到达的地方。     

大楼、大师、"大"学生

大学是培养学生的场所,大楼和大师是必要的办学条件,学生才是大学真正的主角.现行的计划管理体制剥夺了学生的主体地位;大学评估诱发了"形象工程"和"人才工程";教学,在规范化的旗帜下走向了僵化.为此,亟待矫正大学的理念,调整评估方式和考评指标,改变大学管理模式,实施教授治校,弱化行政功能,构建师生之间的制约耦合,运用科学的管理机制,形成现代大学的管理模式,寻求"无为而治"的管理效果.     

专家系统在变压器故障诊断中的应用

为了实现变压器故障诊断的自动化,提高判断的准确性,把人工智能专家系统引入到故障诊断中,该系统采用基于置信度的模糊不精确推理方法,由观测到的信息,利用知识库来推断结论.试验证明,此方法降低了判断的随机性,提高了诊断水平.     

透析营销失败的10大原因

经验主义,没有创新 　　一些企业或个人成功后,总是喜欢用过去的思路经营新的品种.殊不知任何新品都有差异性,他们的消费对象、产品的核心卖点及表现力均是不同的,经验主义很容易使产品销售走弯路,甚至导致营销失败.作为老产品,包装也要常更新,但要沿袭原有的核心记忆点与要素,才能使市场趋于稳定,甚至增长.……     

浅谈抗震设计中影响框架柱延性的因素

要提高框架结构的抗震性能,必须保证结构构件具有足够的延性,从而保证框架结构具有更好的变形能力,以吸收较多的地震能量.因此,抗震设计时,将框架柱设计成延性构件尤为重要.影响框架柱延性的因素有很多,笔者对其进行了分析阐述,以便在设计工作中,有针对性地采取一些措施来改善框架柱的受力性能,确保框架柱有足够的延性,从而提高柱的抗震性能.     

规划绿色小区 创建生态城市

绿色小区、生态城市的建设是人类文明进步的象征,是城市发展的方向.它不仅涉及城市物质环境的生态建设、生态恢复,还涉及到价值观念、生活方式、政策法规等方面.因此,在进行小区规划时,不仅要体现小区建筑和规划本身造型新颖、简洁明快、流畅大方的现代风格,亦要体现生态环保、节能的规划思路.笔者结合小区规划的具体设计实践,阐述了规划绿色小区的设计理念、景观规划设计思想、功能分区特点等构想及实现过程.笔者体会到,要实现规划绿色小区,创建生态城市的目标,必须着眼于未来,立足于现在,从小处、局部规划等点滴细节入手,悉心洞察其功能,细致推敲其寓意,才能营造出人与自然和谐共生的意境,创作出环境宜人、充满现代气息的小区规划作品.     

快淬对La0.7Mg0.3Co0.45Ni2.55-xCux (x=0-0.4)电极合金微观结构及电化学性能的影响

应用铸造及快淬工艺制备了La0 7Mg0.3Co0.45Ni2.55-xCux (x=0, 0.1, 0.2, 0.3, 0.4)贮氢电极合金,研究了快淬工艺对合金微观结构及电化学性能的影响.XRD,SEM及TEM的分析结果表明,铸态及快淬态合金具有多相结构,包括(La,Mg)Ni3相,LaNi5相以及LaNi2相.快淬对合金的相组成没有明显影响,但显著地改变了合金的相丰度.快淬还显著地改善合金的成分均匀性,并使合金的晶粒明显细化.电化学测试的结果表明,快淬大幅度提高合金的电化学循环稳定性,但使合金的放电容量和活化性能下降.快淬对合金的放电电压特性具有明显的影响,当淬速大于15m/s时,快淬降低合金的放电电压,并使放电平台的斜率明显增大.     

发挥整体优势 力推高端产业——南山铝业积极推进发展方式转变

面对新的形势和任务,南山铝业增强忧患意识和风险意识,坚定发展信心,抓住新的历史机遇,充分发挥自身产业链的优势,科学谋划,积极应对,突出重点,着力推进,保持企业的又好又快发展,实现“铸就百年南山”的远大目标。     

基于模板结构和数据库技术定制发动机装配线监控系统

组态软件是工业应用软件的一个组成部分,但随着计算机软件的发展,软件的功能越来越强,对于具体企业、具体生产线,需要进行不同的组态,需要投入更多的时间、精力、人力。论文介绍以Excel表为基础模板表,采用SQL Server 2000为后台数据库,利用数据库提供的数据转换服务(DTS),实现异构数据之间的转换,填充数据库数据模板结构[1],完成数据库数据的准备工作,然后连通监控系统,实现发动机监控系统的定制,提高软件开发效率。     

Comprehensive analysis of delamination in drilling of composite materials with various drill bits

Beside the twist drill, the effects of various drill geometries were rarely discussed in analytical fashion. This study presents a comprehensive analysis of delamination in use of various drill types, such as saw drill, candle stick drill, core drill and step drill. In this analysis, the critical thrust force at the onset of delamination is predicted and compared with the twist drill.     

高含硫和二氧化碳油田钻具的腐蚀及防腐蚀措施

腐蚀是造成钻井过程中钻具损坏的重要因素之一。本文综述了钻井过程中造成腐蚀的原因,钻具的腐蚀类型,以及相应的腐蚀控制措施及材料选用要求。     

枪钻和深孔合金钻在深孔加工的对比应用

介绍了模具加工中深孔加工的不同方式,并结合其各自的特点,进行了详细说明,供读者参考。     

新型叶片式井下动力钻具结构设计

井下动力钻具是一种能把钻井液的能量转化为钻井破岩动力的钻具,它具有能量利用率高、钻进成本低等优点。在西方发达国家,井下动力钻具已被确定为定向井、丛式井、大斜度井、水平井和抢险救援井的最佳钻井工具之一。目前,井下动力钻具主要朝着低速大扭矩的方向发展。而现行的井下动力钻具中,涡轮钻具具有高速大扭矩的软特性,必须同减速器配合使用才能实现低速大扭矩钻井;螺杆钻具容易实现低速大扭矩钻井,但却不耐高温、高压;电动钻具结构过于复杂,目前已很少使用。通过对目前钻井过程的调查与研究,设计一种新型叶片钻具,它基于叶片马达的工作原理,利用叶片上的压差驱动转子转动且容易实现低速大扭矩钻井。     

Effects of exit back-up on delamination in drilling composite materials using a saw drill and a core drill

Machining of composites has caught greater attention in manufacturing of structural parts in aerospace, automobile and sporting goods. Composite materials have advantageous features in strength and stiffness coupled with lightweight compared to the conventional metallic materials. Amongst all machining operations, drilling is the most commonly applied method for generating holes for riveting and fastening the structural assembly. Delamination is one of the serious concerns in drilling holes in composite materials at the bottom surface of the workpiece (drill exit). Quite a few references of the drilling of fiber-reinforced plastics report that the quality of cut is strongly dependent on drilling parameter as well as the drill geometry. Saw drills and core drills produce less delamination than twist drills by distributing the drilling thrust toward the hole periphery. Delamination can be effectively reduced or eliminated by slowing down the feed rate when approaching the exit and by using back-up plates to support and counteract the deflection of the composite laminate leading to exit side delaminations. The use of the back-up does reduce the delamination in practice, which its effects have not been well explained in analytical fashion. This paper predicts the effects of backup plate on delamination in drilling composite materials using saw drill and core drill. The critical drilling thrust force at the onset of delamination is calculated and compared with that without backup. The well known advantage of industrial use of backup can be understood fundamentally by the fact that the threshold thrust force at the onset of delamination is increased making the delamination less induced.     

Taguchi analysis of delamination associated with various drill bits in drilling of composite material

This paper presents a prediction and evaluation of delamination factor in use of twist drill, candle stick drill and saw drill. The approach is based on Taguchi’s method and the analysis of variance (ANOVA). An ultrasonic C-Scan to examine the delamination of carbon fiber-reinforced plastic (CFRP) laminate is used in this paper. The experiments were conducted to study the delamination factor under various cutting conditions. The experimental results indicate that the feed rate and the drill diameter are recognized to make the most significant contribution to the overall performance. The objective was to establish a correlation between feed rate, spindle speed and drill diameter with the induced delamination in a CFRP laminate. The correlation was obtained by multi-variable linear regression and compared with the experimental results.     

Development and performance analysis of new spade bit designs

The purpose of this work is to present the development and experimental performance assessment of a new generation of spade drill bits. Rigorous point geometry and drilling force models that describe the topology of the drill and its cutting behaviour have guided the development of these new drills with unique topological features. It is shown, both analytically through simulations and through a systematic experimental study, that the performance of the newly developed topologies exceeds that of the commercially available designs. The new spade bits yield lower thrust and torque over the whole range of pragmatic operating conditions.     

岩心钻机提下钻机械手的液压系统设计

分析岩心钻机提下钻工艺,确定了机械手在提下钻工作中的任务和具体的动作顺序,设计了提下钻机械手的液压系统,对自动化、智能化岩心钻机的发展与应用具有一定的意义。     

A standard conical point drill grinding machine

This paper describes a drill grinding machine that can produce conical twist drill points with very accurately specified point shapes. The machine is adjusted by precise orthogonal movements using shims and gages to make sure that the drill parameters are set precisely. The confidence in the point shape produced is high enough that inspection of the points produced is not necessary.     

适于精扩孔加工的麻花钻的刃磨改进

介绍了麻花钻的特点、刃磨要领和使用.该钻头扩出的孔具有较好的表面粗糙度,又有较高的孔径精度,在加工过程中能够达到十分理想的效果.