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对“非均匀等离子体湍流重正化准线性理论中的平均电场效应”一文的质疑 总被引:1,自引:1,他引:0
邱孝明 《核聚变与等离子体物理》1999,(2)
文献[1]的作者在该文中把湍性电场的系综平均值E0(x,t)作为基本小量,并用它去定其他各个物理量的数量级。这种做法没有物理根据,也是迄今为止等离子体湍流(不管是均匀还是非均匀)的理论处理中没有先例的:1既然E0(x,t)是湍性电场的系综平均值,那它... 相似文献
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早在1952年,Baez[1]就把全息术的思想推广到X射线领域。可是在以后长达20年的时间里,虽然有许多关于X射线全息术应用潜力的讨论,但是在实验上没有取得大的进展,主要是缺少高亮度的X射线源[2]。直到70年代初期,这种状态才被打破。首先Aoki和Kikuta以及他们的合作者进行了一系列的实验。他们用微聚焦X射线管和同步辐射源,以化学纤维和红血球为样品,记录了一维X射线无透镜傅里叶变换全息图和X射线同轴全息图,重现时获得了4μm的分辨力。1986年,Howells等[3]在Brookhaven… 相似文献
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本文讨论了卡诺循环过程的特点,指出了一些文献[1]-[6]中卡诺循环ρ-V图的问题,并给出了修正意见. 相似文献
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自旋系统是目前唯一可能实现负绝对温度状态的系统,由于自旋与自旋之间的相互作用十分微弱,所以此种系统可看成是理想的.本文对此种理想自旋系统进行了统计讨论,确定了系统的各种热力学函数,并给出了热容量C的表达式及其在 T=±0K、±∞ K时的行为,这些结果与文献[1]、[2]、[3]中所涉及的结果是一致的 相似文献
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曹昌祺先生所著《电动力学》的附录中,对矢量场唯一性定理叙述为:“一个矢量场被它的散度、旋度和边值条件(法线或切线分量)唯一确定.”[2]《大学物理》1986年第11期柯元明的文章[1]认为,切线分量未必能够唯一确定矢量场.笔者在柯文的启示下,提出二源矢量场唯一性定理,作为柯文的补充,把柯文提出的问题和曹先生对唯一性的提法统一起来. 相似文献
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In this paper we present an efficient two-stage method combining the merits of the Taguchi method and neural network software
to achieve nonlinear fine optimal lens grinding parameters for both the roughness and the curvature deviation robust over
a wide range of lens refraction power. Discrete and rough optimal grinding parameters for roughness and for curvature deviation
are first obtained respectively using the Taguchi method with an L18 orthogonal array. Then all the experimental data of the 18 experiments are used as input training data for neural network
software to obtain a set of compromised nonlinear accurate optimal parameters for the roughness and the curvature deviation.
Results of confirmation experiments using these final parameters show that lens surfaces ground with polishers ranging in
curvature from −7:00 to +7.00D are robust in desired quality targets. 相似文献
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《Physica A》2006,363(1):32-38
To improve their position at the market, many companies concentrate on their core competences and hence cooperate with suppliers and distributors. Thus, between many independent companies strong linkages develop and production and logistics networks emerge. These networks are characterised by permanently increasing complexity, and are nowadays forced to adapt to dynamically changing markets. This factor complicates an enterprise-spreading production planning and control enormously. Therefore, a continuous flow model for production networks will be derived regarding these special logistic problems. Furthermore, phase-synchronisation effects will be presented and their dependencies to the set of network parameters will be investigated. 相似文献
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提出一种模糊边界模块化神经网络(FBMNN)的混沌时间序列预测方法,该方法先对混沌时间序列观测点重构的相空间进行模块化划分,划分点的选取由遗传算法自动寻优.然后定义一个模糊隶属度函数,在划分边界一侧按照一定的模糊隶属度设定模糊边界带,通过模糊化处理,解决了各模块划分点附近预测结果的跳跃问题.最后每一模块,及其模糊边界的样本点都对应一个递归神经网络进行训练,通过预测合成模块输出结果.该方法对三个混沌时间序列基准数据集Mackey-Glass,Lorenz,Henon进行实验,结果表明该方法有效地提高了混沌时间序列预测效果.
关键词:
模糊边界
模块化神经网络
混沌时间序列
预测 相似文献
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本文讨论保证透镜高效加工生产线重复精度的两个基本条件:1.加工工序系统间合理的衔接关系;2.加工工序系统中工艺系数的最佳匹配关系。 相似文献
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本文提出了用现有高效线设备批量加工中高精度镜片的方法。对于表面疵病要求Ⅲ级以上的镜片来说,在其它材辅料都能符合要求的情况下,通过采用增加精磨工序、人员调整和改进修模方式后,基本上能实现中高精度镜片的批量生产。 相似文献
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WU Shuoxian 《声学学报:英文版》1994,(3)
I.IntroductionTherearetwowaysofcvaluatingconcertha1lacoustics.Oneistoevaluatetheacousticalqualityofaconcertha11ateachlistener'spositionrespectively,andtheotheristoevaluatetheacousticalqua1ityofaha1lasawho1e.Bothwaysarebasica1lysimilar.Howcvcr,sincesomcob-icchveparametersmayhavedifTerentvalucsatdifferentpositions,onemustdcfinesuitab1ein-dicestodescribetheseparameters(e.g.meanva1ucsorothers),sothatacomparisonbetweenha1lsbecomcspossib1e,Thispaperdea1swiththelattereva1uationbyusingfuzZysettheory… 相似文献
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Jacek Sochacki 《Fiber and Integrated Optics》1989,8(2):107-119
The most recent formulation of the perfect geodesic lens problem is utilized to evaluate a novel solution. This solution describes a smooth geodesic depression profile with a finite value of its local curvature radius at the edge of the lens. This feature should minimize radiation and scattering losses by the guided modes that take place mainly at the lens boundary. The external rounded section of the proposed lens is described by a simple, explicit expression that considerably eases designing procedure. The presented lens is capable of perfect focusing once the theoretically prescribed ideal depression profile is accurately fabricated. For straightforward examination of the influence of technological grinding errors on the lens focal characteristics, a simple analytical method is proposed and investigated. 相似文献
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在回顾了Haldane对量子Hall效应在二维球面S2上的描述后,本文构造了二维模糊球S2上的非对易代数及其Hilbert空间的Moyal结构.通过构造模糊球上不可压缩量子霍尔流体的非对易Chern-Simons理论,求解具有准粒子源的Gaussian约束,找出模糊球上的Calogero矩阵及最低Landau能级Laughlin波函数的完全集,此Laughlin波函数由旋量坐标推广的Jack多项式表示. 相似文献
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This study proposes a beam shaper for converting a circle beam profile generated with a Gaussian intensity distribution by an 808 nm diode laser into a line beam profile for silicon surface treatment applications. To produce a hand-held and low-cost device with a large spot-size laser, this study uses a portable optical system consisting of a diode laser source, a collimator, a cylindrical lens, and a plano-convex lens to generate an approximately 40 × 3:5mm2 line beam profile at a working distance of 200 mm. The silicon surface treated by the line-shaped laser beam has significantly reduced reflectance spectra. The proposed system is also suitable for the surface cleaning of materials. 相似文献