高斯光束微圆孔衍射变换的数值仿真实验

高斯光束的微圆孔衍射变换在微光学、激光技术以及微光机电技术中发挥着基础性作用,通过数值计算模拟实验可以对它进行研究与探索。由菲涅尔-基尔霍夫衍射公式得到单色点源平面屏衍射的积分式,类推得到高斯光束圆孔衍射的积分式,并给出这一积分式的一种数值计算方法。利用Matlab软件进行了高斯光束微圆孔衍射变换的数值仿真实验研究,这有助于激光束的实际衍射实验及其测控理论与技术的研究以及光学教学的改革。     

顾客满意与顾客忠诚关系探究

顾客满意不一定导致重复购买,这就是所谓的顾客满意陷阱.在界定顾客满意和顾客忠诚内涵的基础上,利用卡诺模型和赫茨伯格的双因素理论对这一现象进行分析,试图对客户满意陷阱形成的原因做出解释.     

黑洞理论的辩证唯物主义审视

黑洞理论发展到现代,已被霍金等人用量子理论和广义相对论等理论推进到新的高峰。不过,持“支持黑洞理论”观点和持“反对黑洞理论”观点的科学家们却因为出发点的不同而渐行渐远。全世界的科学家都尝试着用各种方法去证实或反驳该理论所预言的“黑洞”,但收效甚微。因此我们不但要从辩证唯物主义的认识论和方法论出发去审视黑洞理论,更应该用辩证唯物主义的眼光去看待科学发展的新成果。     

何谓大学核心竞争力

随着我国高校办学自主权进一步扩大和中国加入WTO,中国大学面临的国内国际竞争将越来越激烈已是一个不争的事实。中国大学如何提高自身的竞争能力是一个迫在眉睫的紧要问题。当前高教界对大学核心竞争力有一些探讨,但是未能将大学核心竞争力与大学竞争力、大学资源、大学核心能力之间的关系做明确阐述。本文试图对大学核心竞争力与这些方面的关系做一些探讨。     

马克思“世界历史”理论及其方法论意义

马克思运用生产力和生产关系的矛盾运动阐述了“世界历史”理论,为我们正确理解全球化的内涵与影响、科学分析经济全球化的两重性以及准确把握全球化的发展趋势提供了科学的思维方法,为社会主义国家参与经济全球化提供了重要的理论指导。     

Seminal,adventitious and lateral root growth and physiological responses in rice to upland conditions

Understanding the growth and physiological responses of rice to upland conditions would be helpful for designing treatments to improve the tolerance of rice under a rainfed system. The objective of this study was to investigate the initiation, elongation and membrane stability of seminal, lateral and adventitious roots of upland rice after 9-d upland condition treatment. Compared with control roots under waterlogged conditions, upland water deficiency conditions favor seminal and lateral root growth over adventitious root growth by accelerating seminal root elongation, promoting lateral root initiation and elongation, and reducing the elongation and number of adventitious roots. Enhanced total root number and length resulted in increase of total root dry weight and thereby increasing the root-to-shoot ratio. Organic compound leakage from seminal root tips and adventitious roots increased progressively to some extent with upland culture duration, while significant increases in semial root tips were the consequence of loss of membrane integrity caused by the upland-condition enhanced growth. Project (No. G1999011700) supported by National Key Basic Research Special (863) Foundation of China     

薄壁铸件反重力充填的守恒标量法研究

1　Introduction　SofarthemainalgorithmsadaptedtothenumericalsimulationformouldfillingareMAC ,SMAC[1] ,SOLA VOF[2 ] ,SIMPLEconservativescalarmethod[3] ,etc .Tosimulatemoldfilling ,MACandSMACmethodswilloccupylargequantityofcomputermemory ,andcostmuchcomputationtime .Atpresent ,thealgorithmsusedtosimulatemouldfillingofcastingsmainlyfocusonSOLA VOFandSIMPLEconservativescalar .Com paringwithSOLA VOF ,SIMPLEconservativescalaralgorithmismuchmoresuperior .Inaspectofmomen tumequat…     

几种窑型对环境影响的探讨

本文从工艺的角度分析了几种水泥生产窑型对环境的污染及原因,并进行了对比。     

稀土和磷对过共晶Al-Si合金的复合变质作用

The effect of rare earth (RE) elements on the morphologies and sizes of Si phases in the hypereutectic Al-Si alloys modified with P was investigated.The results show that the addition of La element to the hypereutectic Al-Si alloys can enhance the effect of P element on the modification of the primary Si phases.In the multiplex modification of RE-P,the primary Si phase is refiner and the shape of the eutectic Si is changed from long needle-like to short rod-like.Moreover,the agglomeration rate of the primary Si phase is slowed greatly.Even the melt is held for 6 h,the average size of the primary Si phase is still satisfied.The results analyzed by scanning electron microscope (SEM) indicate that La is richer at A1-Si interface than that inα-Al or primary Si phase.The higher the La content in the Al-Si interface,the smaller the primary Si phase.     

伍尔夫的双性同体观管窥

英国著名女作家、文学评论家弗吉尼亚.伍尔夫在《一间自己的房间》中提出了双性同体这一观念,并将其引入文学批评领域,认为这是一种最佳的文学创作状态和批评标准。文章以《一间自己的房间》为依据,探索伍尔夫双性同体观的内涵以及它在作家进行文学创作中所起的作用。