共查询到20条相似文献，搜索用时 125 毫秒
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电场强度是静电学中最基本、最重要的概念之一,也是高考的热点.对场强的求解一般可用其定义式、点电荷场强公式以及匀强电场公式等,但有些电场问题还需一些特殊的处理方法,下面做一简单介绍.1对称法例1一半径为R的绝缘球壳上均匀地带有电荷量为 Q的电荷,现在球壳上挖去半径为r(rR)的一个小圆孔,则此时球心处电场强度的大小为(已知静电力常量为k),方向为.析与解如右图所示,设球壳上挖去M点附近的一个小圆孔,与M点对称的N点附近有一球面,由对称性可知:球壳上除M、N两处外的电荷在球心O处产生的电场的合场强为零,所以球心处的电场强度即为… 相似文献
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单色点源圆孔衍射的数值模拟实验 总被引：2，自引：0，他引：2
根据平面屏衍射的特点,由菲涅尔-基尔霍夫衍射公式得到单色点源圆孔衍射的积分表达式,然后提出了单色点源圆孔衍射的一种数值计算方法,用Matlab软件进行计算机数值模拟实验研究单色点源照射圆孔产生衍射的傍轴区的光场,有助于对相关衍射实验及衍射理论与技术的进一步研究。这种计算机仿真方法扩展了衍射问题的研究途径与方法,具有一定的应用价值,尤其对于教学具有直观作用。 相似文献
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类比干涉原理,利用菲涅尔圆孔(屏)衍射公式来计算"光滑"小球体的表面光洁度,并简要分析其局限。通过理论推导和实验分析,得出用菲涅尔圆孔(屏)衍射研究球体的光洁度是可行的方法。 相似文献
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《第二课堂(小学)》2004,(4)
这架投影幻灯机是用凸透镜放大成实像的原理制成的。它可以放映一般的幻灯片,用来做教具很合适。箱体:箱体可用废油漆筒做成。先把铁筒的上底(原来开口倒漆的一面)剪去,当做箱底。把铁筒的下底倒过来当做箱顶,在它的正中心处开一个直径比聚光镜略小5mm的圆孔。箱体左右两 相似文献
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朱辰 《青少年科技博览(中学版)》2003,(6)
我发明的简易晾衣绳既新颖又实用,它解决了家中晾衣临时绑绳,用后再解绳的麻烦。它的结构十分简单(图1),其外形是一个圆筒,内有一轴用来缠绕绳子,在轴的上方设有弹簧起固定作用。筒外中间处有两个对着的圆孔,各有一个用绳子系住的铁钩,其中一个铁钩是固定的,另一个可以任意拉长。在筒的上方有一个收线摇柄。 相似文献
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采用Zernike多项式拟合元件位相畸变的方法,提出了波前畸变圆孔衍射模型,并进行了波前畸变圆孔衍射及其和理想状态下圆孔衍射的比较.通过分析,不同波长经过球差波前畸变圆孔衍射,最大光强分布的位置是不同的,与理想圆孔衍射的光强分布位置差别比较大,波前畸变对衍射光强分布有很大的影响. 相似文献
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朱岩 《荆门职业技术学院学报》1998,13(1):22-29
本文从理论上确定了核壳结构乳液聚合过程中补加乳化剂量的计算方法,并且运用此方法计算出在有关试验中补加的乳化剂量,制得了稳定的核壳结构聚合物乳液。 相似文献
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Meng PQ Hou G Zhou GY Peng JP Dong Q Zheng S 《Journal of Zhejiang University. Science. B》2005,6(9):853-858
The ZM-1 tissue microarrayer designed by our groups is manufactured in stainless steel and brass and contains many features that make TMA （tissue microarray） paraffin blocks construction faster and more convenient. By means of ZM-1 tissue microarrayer, biopsy needles are used to punch the donor tissue specimens respectively. All the needles with the punched specimen cylinders are arrayed into the array-board, with an array of small holes dug to fit the needles. All the specimen cylinders arraying and the TMA paraffin block shaping are finished in only one step so that the specimen cylinders and the paraffin of the TMA block can very easily be incorporated and the recipient paraffin blocks need not be made in advance, and the paraffin used is the same as that for conventional pathology purpose. ZM-1 tissue microarrayer is easy to be manufactured, does not need any precision location system, and so is much cheaper than the currently used instrument. Our method＇s relatively cheap and simple ZM-1 tissue microarrayer technique of constructing TMA paraffin block may facilitate popularization of the TMA technology. 相似文献
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MENG Pan-qing HOU Gang ZHOU Gui-ying PENG Jia-ping DONG Qi ZHENG Shu 《Journal of Zhejiang University. Science. B》2005,6(9)
The ZM-1 tissue microarrayer designed by our groups is manufactured in stainless steel and brass and contains many features that make TMA (tissue microarray) paraffin blocks construction faster and more convenient. By means of ZM-1 tissue microarrayer, biopsy needles are used to punch the donor tissue specimens respectively. All the needles with the punched specimen cylinders are arrayed into the array-board, with an array of small holes dug to fit the needles. All the specimen cylinders arraying and the TMA paraffin block shaping are finished in only one step so that the specimen cylinders and the paraffin of the TMA block can very easily be incorporated and the recipient paraffin blocks need not be made in advance, and the paraffin used is the same as that for conventional pathology purpose. ZM-1 tissue microarrayer is easy to be manufactured, does not need any precision location system, and so is much cheaper than the currently used instrument. Our method's relatively cheap and simple ZM- 1 tissue microarrayer technique of constructing TMA paraffin block may facilitate popularization of the TMA technology. 相似文献
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Meng Pan-qing Hou Gang Zhou Gui-ying Peng Jia-ping Dong Qi Zheng Shu 《浙江大学学报(A卷英文版)》2005,6(9):853-858
The ZM-1 tissue microarrayer designed by our groups is manufactured in stainless steel and brass and contains many features
that make TMA (tissue microarray) paraffin blocks construction faster and more convenient. By means of ZM-1 tissue microarrayer,
biopsy needles are used to punch the donor tissue specimens respectively. All the needles with the punched specimen cylinders
are arrayed into the array-board, with an array of small holes dug to fit the needles. All the specimen cylinders arraying
and the TMA paraffin block shaping are finished in only one step so that the specimen cylinders and the paraffin of the TMA
block can very easily be incorporated and the recipient paraffin blocks need not be made in advance, and the paraffin used
is the same as that for conventional pathology purpose. ZM-1 tissue microarrayer is easy to be manufactured, does not need
any precision location system, and so is much cheaper than the currently used instrument. Our method's relatively cheap and
simple ZM-1 tissue microarrayer technique of constructing TMA paraffin block may facilitate popularization of the TMA technology.
Project (No. G1998051200) supported by the National Basic Research Program (973) of China 相似文献
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PANTsomg-Whay GLOWINSKIRoland JOSEPHDanielD 《浙江大学学报(A卷英文版)》2005,6(2):97-109
We present the simulation of the dynamics of fluid-cylinder interactions in a narrow three-dimensional channel filled with a Newtonian fluid, using a Lagrange multiplier based fictitious domain methodology combined with a finite element method and an operator splitting technique. As expected, a settling truncated cylinder turns its broadside perpendicular to the main stream direction and the center of mass moves to the central axis of the channel. In the case of two truncated cylinders, they first move around each other for a while and then stay together in a "T" shape. After the "T" shape has been formed for a long enough time, we found no vortex shedding behind the cylinders. When simulating the fluidization of 60 truncated cylinders, we captured the features of interactions among fluidized cylinders as observed in experiments. 相似文献
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衣型柱面的建立主要通过制作最小柱面围、获取人体模型最小柱面围、制作衣型柱面三个步骤完成。以所建立的衣型柱面为参照,通过实验,数据求证和检测,有助于理清衣型柱面立体余缺到平面省道的转化关系,即余缺空间方位与省道平面位置的对应关系、余缺空间与平面省道大小比例的对应关系和余缺空间与平面省道形状的对应关系。 相似文献
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连续式大直径圆柱壳结构上的波力数值模型 总被引：2，自引：0，他引：2
以线性波理论为基础 ,应用满足两条平行线性边界的无限条形区域的 Helmholtz方程的基本解 ,采用边界单元法建立了连续式大直径圆柱壳结构的一种反射波波力数值模型 .根据本模型的理论与方法 ,采用 Visual C 语言编制了计算程序 .算例计算表明了本方法与程序的有效性 ,并且将作用在连续式大圆柱壳结构的波浪力与方沉箱结构相比较 ,在 D/L=0 .0 9～ 0 .19情况下可降低 14 %～ 2 4% 相似文献
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介绍利用ＡｕｔｏＬＩＳＰ语言编写程序,在ＡｕｔｏＣＡＤ中实现参数化绘图的方法,实现自动处理并绘制等径正交、异径正交、异径偏交的两圆柱全贯时相贯线和展开图。 相似文献
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INTRODUCTION In scientific and engineering problems, Volterra integral equations are always encountered and have attracted much attention (Christopher and Baker, 1977; Delves and Mohamed, 1985; Brunner and van der Houwen, 1986; Kress, 1989; Oja and Saveljeva, 2002; Maleknejad and Shahrezaee, 2004; Maleknejad and Aghazadeh, 2005; Zerarka and Soukeur, 2005). Generally, exact solutions are very difficult to find and solutions have been obtained for only some few special cases (Yan and … 相似文献
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通过对车用压缩天然气气瓶的发展简述,说明了天然气汽车的发展带动了车用压缩天然气气瓶的发展和进步。另外,在车用压缩天然气气瓶发展的同时,也应注重车用压缩天然气气瓶的安全使用,重视车用压缩天然气气瓶的检验。 相似文献