共查询到20条相似文献，搜索用时 15 毫秒
1.
结合面接触问题对数控机床动态特性影响非常大,是决定机床系统总刚度和总阻尼的主要因素.本文总结了机床机械结合面接触刚度研究中常用的三种模型,即赫兹接触模型、G-W统计接触模型和分形接触模型,并根据三维W-M函数,利用Matlab仿真模拟了表面的三维粗糙形貌,分析了分形参数G和D的含义. 相似文献
2.
利用二维贴片法对人体胫骨进行测试实验,用二维光路同步记录了x、y方向的云纹图像,据此图像测定胫骨的弹性常数、应变及位移,测试结果与电测法相比,误差小,灵敏度高． 相似文献
3.
3D MAX是当前流行的三维设计与制作软件,3D MAX设计的作品同样面临侵权问题。提出了一种在3D MAX软件中实现的数字水印算法。在3D MAX中,利用创建面板中的二维图形工具,在视图中创建一个二维图形,通过分析二维图形的特性,在二维图形的顶点或边上选择合适的位置来嵌入水印。然后利用添加编辑修改器的方法,将二维图形转换为三维模型,最后将三维模型渲染输出。三维模型在使用过程中发生版权纠纷时,可以分析三维模型的二维基础图形,利用嵌入水印的逆过程将水印提取出来,以此为依据来判断版权归属,从而可以保护3D MAX设计作品的版权。 相似文献
4.
光照及黑暗条件下不同浓度2，4-D对诱导苦马豆愈伤组织的影响 总被引：1，自引：0，他引：1
以苦马豆幼苗的子叶及下胚轴为外植体,研究了光照及黑暗条件下不同浓度2,4-D对苦马豆愈伤组织生长量的影响．结果表明：予叶愈伤组织的生长均优于下胚轴愈伤组织的生长,2,4-D浓度为0．3,0．6mg／L时,子叶、下胚轴愈伤组织的生长光培养优于暗培养;在2,4-D浓度为1．2mg／L时,子叶、下胚轴愈伤组织的生长暗培养优于光培养．因此,以2,4-D单激素诱导苦马豆愈伤组织,子叶培养在暗处是最好的选择． 相似文献
5.
3-D scattering of obliquely incident plane p waves by alluvial valley embedded in layered half-space
The indirect boundary element method(IBEM) was established to solve the problem of 3-D seismic responses of 2-D topographies,by calculating the free-field responses with the direct-stiffness method and simulating the scattering wave fields with the dynamic Green’s functions of moving distributed loads.The proposed method yields accurate results,because the 3-D dynamic stiffness matrixes used are exact and the fictitious moving distributed loads can be acted directly on the interface between the alluvial valley and the layered half-space without singularity.The comparison with the published methods verifies the validity of the proposed method.And the numerical analyses are performed to give some beneficial conclusions.The study shows that 3-D scattering by an alluvial valley is essentially different from the 2-D case,and that the presence of soil layer affects not only the amplitude value of surface displacements but also the distribution of surface displacements. 相似文献
6.
提出了一种能有效实现物体表面三维图像数据配准的算法.该算法利用了三维数据采集时的三维点的阵列信息,这些三维点的阵列信息在采集原始三维数据时可以很容易获得,同时,还利用了三维数据矢量/顶点相似特征作为数据匹配的基础.采用迭代最小均方误差算法来自适应优化变换矩阵参数.这些方法可以有效地提高三维图像配准的性能,加快匹配过程的运算速度.实验结果表明该算法可以获得较好的配准后三维图像的主观效果.尽管该方法主要针对人头模型,但经过少许修改后即可适用于其他物体. 相似文献
7.
Calculating the current distribution in circular loop scatterers commonly involves complicated computation. In this paper,
based on the theory of Maxwellian circuits (MC), we propose a fast algorithm by solving a wave equation with constant parameters
corresponding to the circular loop. Our method prodeces similar results compared to the methods using method of moments (MoM)
with lower computational complexity. It is effective when there are parallel multiple circular loop scatterers. Experimental
results show accuracy of the method. 相似文献
8.
基于分形维前臂动作表面肌电信号的分类 总被引：1，自引：0，他引：1
通过分形维对表面肌电信号进行识别分类.在30个健康志愿者做前臂内旋和外旋时,从他们的右前臂肌前群分别采集2类动作表面肌电信号.当原始动作表面肌电信号用小波包变换分解成几个子信号后,采用一种基于模糊自相似性的方法计算原始信号和4个子信号的分形维.结果表明:从频带0～125 Hz的子信号求得的内旋和外旋动作表面肌电信号的分形维有各自的范围;通过该分形维进行Bayes决策时,错误识别率仅2.26%.因此,该分形维适合用来识别内旋和外旋动作表面肌电信号. 相似文献
9.
2,4-D和6-BA对点地梅愈伤组织诱导的影响 总被引：2，自引：0，他引：2
聂勇 《阿坝师范高等专科学校学报》2006,23(4):126-128
以点地梅(A.umbellate(Lour.)Merr.)无菌苗的嫩叶为外植体,研究了不同质量浓度的2,4-D和6-BA对愈伤组织诱导的影响。结果表明:较高浓度的2,4-D(1.0～2.0 mg/L)单独使用能促进愈伤组织形成,随着2,4-D质量浓度的增加,愈伤组织的形成逐渐变弱;在培养基、2,4-D和6-BA诱导愈伤组织的正交试验中,发现诱导愈伤组织的较优培养基组合为MS+2,4-D 1 mg/L+6-BA 0.4 mg/L,且产生的愈伤组织多为淡绿色、质地疏松、生长快、褐化时间长,适合于点地梅愈伤组织的诱导。 相似文献
10.
Characterization of a-Si:H/SiN multilayer waveguide polarization using an optical pumping application—LED 总被引：1，自引：1，他引：0
Mohd Saiful Dzulkefly Zan Isamu Kato Mohammad Syuhaimi Ab-Rahman Seri Mastura Mustaza 《浙江大学学报(A卷英文版)》2009,10(10):1421-1427
This paper describes the fabrication of a waveguide and the analysis of its polarization characteristics by applying light-emitting diode （LED） pumping lights to its surface. By using double tubed coaxial line （DTCL） microwave plasma chemical vapor deposition （MPCVD） equipment, an a-Si：H/SiN multilayer waveguide was fabricated whose thickness could be controlled at nanometer order. The main structural material of the waveguide sample consisted of a combination of layers of amorphous silicon hydrogen and silicon nitrate. Once the sample was ready, another major objective of the experiment was to analyze the polarization characteristics of the fabricated waveguide. The idea of the experiment was to analyze how the waveguide reacts when three types of LED （blue, yellow, and red） are radiated onto its surface. The results showed that the fabrication of the a-Si：H/SiN sample is successful. Most effective transmission results, which accord with the polarization characteristics analysis, were obtained. 相似文献
11.
在模拟人体生理条件下,用荧光光谱和紫外可见吸收光谱法研究了不同温度下4-(2-羧基苯偶氮)-连苯三酚(CBAP)与人血清白蛋白(HSA)的相互作用.结果表明,CBAP对HSA的荧光猝灭属静态猝灭.通过288、293、298 K时的荧光猝灭,得出CBAP与HSA的结合常数K分别为1.62×106,3.97×105和3.56×105,结合位点数n=0.92(平均值).据F(o)rster非辐射能量转移理论计算出CBAP与HSA的结合距离r=1.44 nm,由热力学参数焓变和熵变,推断两者反应时氢键和范德华力可能起主要作用.运用同步荧光和三维荧光技术分析了CBAP对HSA构象的影响,表明CBAP的加入改变了HSA中酪氨酸残基和色氨酸残基的构象. 相似文献
12.
Three-layer slab waveguide with left-handed materials （LHM） is discussed using the Maxwell＇s equations and their equations of dispersion relation for TM modes are obtained. By seeking the power of the slab waveguide, their equations of effective thickness for TM modes are obtained. Furthermore, the interrelated equations for right-handed materials （RHM） slab waveguide are introduced and their curves plotted. To find new properties for LHM slab waveguide, the equations and their curves for the LHM and RHM slab waveguide are compared respectively. 相似文献
13.
新课程提出了“知识与技能、过程与方法、情感态度价值观”的三维目标。本文尝试着从知识观的角度对目标“三维”的合理性进行了论证,对“三维”目标的内涵及关系进行了解读,并提出了新课程实施过程中三维目标的整合策略。 相似文献
14.
运用模式匹配法，分析了圆-圆形槽波导结的散射特性．在圆-圆形槽波导结上匹配电场和磁场的边界条件，然后在边界方程两边同乘以圆波导和圆形槽波导的模式方程，得到了散射矩阵方程，结的散射系数可由此方程得出．然后分析了圆形槽波导中放置圆形膜片的散射特性．最后讨论了数值计算结果的收敛性；当选择恰当的模式组时，得到了收敛的数值结果，同时给出了膜片散射系数的频率响应结果． 相似文献
15.
A new improved Goh's 3-D wavelet transform(WT) coding scheme is presented in this paper. The new scheme has great advantages including a simple code structure, low computation cost and good performance in PSNR, compression ratios and visual quality of reconstructions, when compared to the other existing 3-D WT coding methods and the 2-D WT-based coding methods. The new 3-D WT coding scheme is suitable for very low bit-rate video coding. 相似文献
16.
More efficient ground truth ROI image coding technique： implementation and wavelet based application analysis 总被引：1，自引：0，他引：1
KUMARAYAPA Ajith ZHANG Ye 《浙江大学学报(A卷英文版)》2007,8(6):835-840
In this paper, more efficient, low-complexity and reliable region of interest (ROI) image codec for compressing smooth low texture remote sensing images is proposed. We explore the efficiency of the modified ROI codec with respect to the selected set of convenient wavelet filters, which is a novel method. Such ROI coding experiment analysis representing low bit rate lossy to high quality lossless reconstruction with timing analysis is useful for improving remote sensing ground truth sur- veillance efficiency in terms of time and quality. The subjective [i.e. fair, five observer (HVS) evaluations using enhanced 3D picture view Hyper memory display technology] and the objective results revealed that for faster ground truth ROI coding applications, the Symlet-4 adaptation performs better than Biorthogonal 4.4 and Biorthogonal 6.8. However, the discrete Meyer wavelet adaptation is the best solution for delayed ROI image reconstructions. 相似文献
17.
This study was aimed at investigating the sampling strategies for 2 types of figures: 3-D cubes and human faces.The research was focused on: (a) from where the sampling process started; (b) in what order the figures' features were sampled. The study consisted of 2 experiments: (a) sampling strategies for 3-D cubes; (b) sampling strategies for human faces. The results showed that: (a), for 3-D cubes, the first sampling was mostly located at the outline parts, rarely at the center part; while for human faces, the first sampling was mostly located at the hair and outline parts, rarely at the mouth or cheek parts, in most cases, the first sampling-position had no significant effects on cognitive performance and that (b), the sampling order, both for 3-D cubes and for human faces, was determined by the degree of difference among the sampled-features. 相似文献
18.
A new proof of the row Cayley-Hamilton theorem for 2-D system was given in this note. In a similar way, the Column Cay-ley-Hamilton theorem was also presented and proved. 相似文献
19.
This study was aimed at investigating the sampling strategies for 2 types of figures: 3-D cubes and human faces. The research was focused on: (a) from where the sampling process started; (b) in what order the figures' features were sampled. The study consisted of 2 experiments: (a) sampling strategies for 3-D cubes; (b) sampling strategies for human faces. The results showed that: (a), for 3-D cubes, the first sampling was mostly located at the outline parts, rarely at the center part; while for human faces, the first sampling was mostly located at the hair and outline parts, rarely at the mouth or cheek parts, in most cases, the first sampling-position had no significant effects on cognitive performance and that (b), the sampling order, both for 3-D cubes and for human faces, was determined by the degree of difference among the sampled-features. 相似文献
20.
采用密度泛函(DFT)计算方法,在UB3LYP/6-311 G(3d,2p)水平上优化了过渡金属正离子乙炔络合物M(C2H2) (M=Sc,Ti,V)不同自旋态的稳定几何构型,并对此络合物体系的全部振动频率进行了计算和全面分析。结果表明,能量较低的高自旋态M 与C2H2在形成络合物时,M 的价电子要发生翻转,形成稳定的低自旋态络合物。根据频率分析,所计算的振动频率值反映出低自旋态络合物比高自旋态络合物有较强的M-C键,在形成低自旋态络合物的同时,过渡金属正离子M 已活化了乙炔的C-C三键和C-H键。 相似文献