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1.
几乎正则图的全符号控制 总被引：1，自引：2，他引：1
1IntroductionFor notation and graph theory terminology we ingeneral follow[1].LetG=(V,E)be a graph with thevertex setVand the edge setE,andletvbe a vertexinV.The open neighborhood ofvisN(v)={u∈V|uv∈E}and the closed neighborhood ofvisN[v]={v}∪N(v).The d… 相似文献
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In this work, a novel morphing machining strategy （MMS） is proposed. In the method, the workpiece is progressively carved out from the stock. Pitfalls in conventional iso-height strategy, such as sharp edges and unevenly distributed left-over materials, are overcome. Moreover, to calculate different levels in the MMS, an energy-based morphing algorithm is proposed. Finally, the proposed strategy is employed in the machining of artificial bone represented by a T-spline surface. The excellent properties of T-spline, such as expressing complex shapes with a single surface, have been well adopted to artificial bone fabri- cation. Computer simulation and the actual machining of the middle finger bone show the feasibility of the proposed strategy. 相似文献
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The design methods of anode and cathode are proposed for precision profile grinding.Based on the electrolytic machining theory, electrolytic equilibrium condition and Faraday‘s law of electrolysis are applied to establishing the mathematical model of profile diamond dressing processes. A finite element method (FEM) program is developed to solve the inverse boundary problem of Laplace‘s equation. Desired anode contour or cathode shape is determined by computing the distribution of electric potential layer by layer. Electrolytic machining experiment is carried out to verify the simulated anode shape. The research result shows that shape deviation between designed cathode and profile wheel increases with the value of angle between feed rate and the normal to anode surface. The shape of simulated anode is consistent with the contour of metal-bonded diamond profile wheel for a given cathode. Based on the anode contour, cathode shape can also be designed accurately. 相似文献
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Let G=(V, E)be a simple graph without isolated vertices. For positive integer κ, a 3-valued function f:V → {-1, 0, 1} is said to be a minus total k-subdominating function(MTκSF)if ∑u∈N(u)f(u)≥ 1 for at least κ vertices v in G, where N(v)is the open neighborhood of v. The minus total κ-subdomination number γ-κt(G)equals the minimum weight of an MTkSF on G. In this paper, the values on the minus total κ-subdomination number of some special graphs are investigated. Several lower bounds on γ-κt of general graphs and trees are obtained. 相似文献
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In this paper, the open queueing network model is proposed for solving the problem of public transportation in cities. The
vertices of the networks (i.e., the bus stops) are determined by means of the fuzzy clustering method. The arcs (i.e., the
paths of the public transportation) can be set up by using the shortest path model in the time sense or the 0–1 integer programming
method. Applying the statistics method, we can calculate the parameters (such as the passenger flow’s distribution, passenger
flow’s transition probability, mean waiting time for the bus etc.) of the public transportation network. In this paper, we suggest to divide the network into two or three stages to implement
the public transportation system in the form of “frog jumping” fast transfer and “permeation” fast dispersion. Combining the
computer simulation and the evaluation of the achievement and effect of public transportation system, we modify the model
so as to solve the public transportation problem better. 相似文献
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在弱碱性（ｐＨ：10～11无机水基电解液中，针对YG类硬质合金材料，采用双极性脉冲电流电解一磨料流喷射的电液束复合加工方法，对加工机理及加工过程进行了初步的分析和研究．在实验的基础上，总结出电参数、电解液参数等主要工艺参数对材料去除率、加工精度、表面粗糙度、电流效率等工艺性能指标的作用规律，并获得了较好的加工效果．其中，材料去除率最高为130mm3／min，加工精度达0．08mm． 表面粗糙度达 Ra 0．4 μm． 相似文献
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In order to design birefringent holey fiber with beat-length independent of wavelength, an asymmetric structure is introduced to reduce its wavelength-sensitivity. The influence of structural parameters on the modal birefringence is calculated and analyzed. After optimizing the parameters, a flat dispersion curve of beat-length is obtained. The beat-length changes from 89.8 mm to 91.0 mm in wavelength range from 1.1 μm, to 1.7 μm, and its relative variation is 1.38%. If this fiber is made into zero-order qu... 相似文献
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A wideband cavity-backed slot antenna operated in the ultra-high frequency(UHF)band is introduced.The antenna has a compact structure and low profile with the size ratio of the ground plane to the slot only 1.6:1.The measured impedance bandwidth of VSWR≤3 achieves 85.3%,covering a frequency range from 390 MHz to 970 MHz.The measured gain is about 5.5～7.5 dB. 相似文献
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The effects of the concentration of dissolved total organic carbon (TOC), the TOC/Br- ratio, bromide ion levels, the chlorine to ammonia-N ratio (Cl:N), the monochloramine dose and the chlorine dose on the formation of trihalomethanes (THMs) (including chloroform, bromodichloromethane, chlorodibromomethane, and bromoform) from chlorination were investigated using aqueous humic acid (HA) solutions. The profile of the chloramine decay was also studied under various bromide ion concentrations. Monochloramine decayed in the presence of organic material and bromide ions. The percentage of chloroform and brominated THMs varied according to the TOC/Br- ratio. Total THMs (TTHMs) formation increased from 112 to 190 μg/L with the increase concentrations of bromide ions from 0.67 to 6.72 mg/L, but the chlorine-substituted THMs were replaced by bromine-substituted THMs. A strong linear correlation was obtained between the monochloramine dose and the formation of THMs for Cl:N ratios of 3:1 and 5:1. These ratios had a distinct effect on the formation of chloroform but had little impact on the formation of bromodichloromethane or chlorodibromomethane. The presence of bromide ions increased the rate of monochloramine decay. 相似文献
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LU Bao - qi 《上海大学学报(英文版)》2005,9(4):365-368
Infrared （IR） absorption spectra and X-ray powder diffraction （XRD） patterrns of sexpenfine cat＇s eye from Sichuan Province have been investigated, and infrared absorption bands of the serpentine have been assigned in this paper. The results indicate that the bands near 3 600 - 3 700 cm^-1 belong to the stretching absorption band VOH, the bands in 948 - 1 100 cm^-1 axe assigned to the stretching vibraling band Usvo, and the bands at 600 570 and 440 cm^-1 respectively belong to the bending vibration band VOH, δMg-O and δSi-O. The serpentine cat＇ s eye includes two types： chrysotile and antigorite. Chrysotile has a sharp and intensive band at 3 688 cm^-1 and a weak band at 3 643 cm^-1 , while antigorite has only one intensive band in the region. At vibration band VSi-O, chrysotile and antigorite have a similar feature at 1 071 cm^-1, but the band at 980 cm^-1 in anfigorite has been split into two bands in chrysotile - a strong one at 1 027 cm^-1 and a weak one at 949 cm^-1. In addition, antigorite has a characteristic bending vibrating band δMg-O at 570 cm^-1. Based on the analysis of the feature of crystal structure, their IR differences axe well explained. 相似文献
12.
Mesh sharpening via normal filtering 总被引：1，自引：0，他引：1
We present a robust mesh sharpening approach to reconstructing sharp features from blended or chamfered features, even with noise and aliasing errors. Feature regions were first recognized via normal variation according to the user＇s input, and then normal filtering was applied to faces of feature regions. Finally, the vertices of the feature region were gradually updated based on new face normals using a least-squares error criterion. Experimental results demonstrate that the method is effective and robust in sharpening meshes. 相似文献
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曹劲 《福建师大福清分校学报》2008,(5):38-41
反转法建立解析式求出凸轮理论廓线方程,再根据包络原理求出实际廓线方程和铣刀加工中心轨迹方程。同时计算出凸轮压力角及其曲率半径验证凸轮设计的合理性和可行性。通过编程运算可对复杂凸轮轮廓曲线精确求解而获得数控加工过程中走刀路线上各点的坐标。 相似文献
14.
Holistic tin-plating on the outer conductor is one of the key processes in the manufacture of semi-flexible coaxial cable, which is widely applied to the third generation (3G) mobile communication system. However, in the traditional horizontal tin-plating process, disadvantages such as the pinhole defects and low productivity effect cannot be avoided. In this paper, a vertical tin-plating process was proposed to reduce the pinhole defects and improve the tincoating quality. Compared with the traditional horizontal tin-plating process, the immersion length was reduced from 300-400 mm to 10-100 mm and the tin-plating time was reduced from 7 s to 3 s in the proposed method. The experimental results indicate that immersion length and time are key parameters for the tin-plating quality. With this new tin-plating process, the experimental results show that the pinhole defects can be eliminated effectively by controlling the immersion depth below 100 mm and tin-plating time at 3 s. The thickness of tin-coating increased from not more than 5 μm to 12.3 μm with the proposed vertical tin-plating process. Meanwhile, the thickness of the intermetallic compounds (IMCs) layer between the tin-coating and copper wires was reduced from 3.26 μm to 0.62 μm if the immersion time decreased from 30 s to 1 s. Besides, a self-developed flux, which possesses a boiling point or decomposed temperature of active components over 300℃, exhibits a better efficiency in reducing the pinhole formation. 相似文献
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根据摆动从动件圆柱凸轮现状、发展趋势以及应用软件等相关概况研究其轮廓曲线的解析设计,提出设计方案,并在VB软件实现廓线的参数化,从而实现了圆柱凸轮的参数化造型和加工。 相似文献
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A graph is called claw-free if it does not contain a claw as its induced subgraph. In this paper, we prove the following results : 1 ) If G is a 2-connected claw-free graph on n vertices, then for any vertex υ and any two distinct vertices x and y in V(G) - |υ| , G has a path containing v and all neighbors of v and connecting x and y;2) Let C be the longest cycle in a 3-connected claw-free graph G and H a component of G - C,and if H is connected but not 2-connected, then there exist nonadjacent vertices u and v in H such that |V(C)| ≥3(d(u) d(u)) -2. 相似文献
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郑哲民 《商丘师范学院学报》2012,(6):1-18
系统地记录中国蚱总科中羊角蚱属、柯蚱属及台蚱属的种类,以检索表形式进行分类研究,共记述羊角蚱属33种,柯蚱属29种,台蚱属55种,其中包括7新种,即广东羊角蚱Criotettix guangdongensis sp.nov.、广州柯蚱Coptotettix guangzhouensis sp.nov.、尖峰柯蚱Coptotettix jianfengensis sp.nov.、直缘柯蚱Coptotettix orthomarginis sp.nov.、海南台蚱Formosatettix hainanensis sp.nov.、波股台蚱Formosatettix undulatifemura sp.nov.及黑胫台蚱Formosatettix nigritibia sp.nov..模式标本保存于陕西师范大学动物研究所. 相似文献
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Rahman S Khalid N Zaidi JH Ahmad S Iqbal MZ 《Journal of Zhejiang University. Science. B》2006,7(9):732-737
INTRODUCTION Blood-Pb levels are taken as representative of dose/exposure, as all clinical symptoms resulting from the toxic effects of Pb are manifested mainly in blood. Lead exposure of children correlates with de- creased IQ, symptoms of hyper kinesis or minima brain dysfunction, poor learning, or defects in specific neuromotor tasks (Landgrin et al., 1980). Large number of observations over the years has associated lead exposure with human diseases (McMichael and Johnson, 1982). Ca… 相似文献
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通过分析凸轮从动件的运动规律,利用Inventor软件设计凸轮轮廓,并根据生成的位移、速度、加速度曲线图判断凸轮轮廓曲线性能的优劣。该方法融合了图解法和解析法两者的优点,使得凸轮轮廓曲线设计更为简便、精确,对缩短设计周期以及后续凸轮数控加工都有着重要的实际意义。 相似文献
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李明楚 《天津大学学报(英文版)》2003,9(4):273-278
A known result by Jackson Bill is that every 2-connected k-regular graph on at most 3k vertices is Hamiltonian. In this paper, it is proved that every 2-connected k-regular claw-free graph on at most 5k( k ≥ 10) vertices is Hamiltonian. Moreover, the bound 5k is best possible. A counterexample of a 2-connected k-regular claw-free non-Hamiltonian graph on 5k 1 vertices is given, and it is conjectured that every 3-connected k-regular claw-free graph on at most 12k-7 vertices is Hamihonian. 相似文献