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We show that planar embeddable -connected Laman graphs are generically non-soluble. A Laman graph represents a configuration of points on the Euclidean plane with just enough distance specifications between them to ensure rigidity. Formally, a Laman graph is a maximally independent graph, that is, one that satisfies the vertex-edge count together with a corresponding inequality for each subgraph. The following main theorem of the paper resolves a conjecture of Owen (1991) in the planar case. Let be a maximally independent -connected planar graph, with more than 3 vertices, together with a realisable assignment of generic distances for the edges which includes a normalised unit length (base) edge. Then, for any solution configuration for these distances on a plane, with the base edge vertices placed at rational points, not all coordinates of the vertices lie in a radical extension of the distance field.
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非均匀有理B样条(NURBS)是CAD设计中广泛使用的技术。本基于平面几何知识给出了三角形约束的圆与椭圆曲线的NURBS表示,为工程设计中使用这类曲线提供了可计算性。 相似文献
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Hui-zhen Li Xiang-wen Chen Si-wei Lyu 《International Journal of Infrared and Millimeter Waves》1999,20(5):867-881
This paper presents a quasi-optical resonator that design methode basic on IBM PC computer (CAD). There is an exellent method to calculate global optima of the fundamental mode power, fractional power of the fundamental mode and combining efficiency etc. It also presents a process of CAD of microcomputer. 相似文献
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介绍某单位CMIS系统中工程设计分系统(EDS)系统的组成,功能,信息关系以及关键技术的实现方法:经过在支撑软件EUCLID3上的二次开发,增加特征建模模块,CAPP系统和专用NC后置处理程序,EDS成为一个基于特征的CAD/CAPP/CAM一体化系统,分系统通过Oracle数据库转换接程序,实现与其它分系统的数据通讯和共享。 相似文献
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通过对行波管周期永磁聚焦系统(PPM)的理论分析,开发了2维模拟软件UESTC_PPM。该软件主要用于模拟轴对称的永磁结构,在圆柱坐标系下,采用有限差分的方法迭代求解磁钢内外任意位置处的磁感应强度分布。模拟了单磁环结构以及单周期结构,将结果与Ansoft Maxwell 3D的模拟结果进行了对比,结果表明:轴上、轴向以及径向磁感应强度的分布图均很接近,但UESTC_PPM软件耗时较短,验证了UESTC_PPM的正确性,并具有一定的精确度。 相似文献
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抗病毒药物具有广泛的应用,对人类和动物的健康有着重要的作用。但抗病毒药物紫外吸收差异大、极性分布广,要实现该类药物的同时分析较为困难。本实验以Click TE-Cys为固定相,结合电雾式检测(CAD),建立了多种抗病毒药物同时分离分析的方法。考察了不同的检测器、色谱模式、色谱柱和流动相对抗病毒药物峰形、分离选择性及检测信号响应的影响。在优化的条件下定量分析了5种抗病毒药物,结果证明该方法具有较好的日内重复性(RSD≤3.06%)和日间重复性(RSD≤5.38%)。同时,该方法还具有较宽的线性范围(0.07~2.28 mg/mL)和较高的灵敏度(LOQ≤0.04 mg/mL),可用于相关药物的定量、定性分析。 相似文献
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《Arabian Journal of Chemistry》2022,15(3):103657
This work describes for the first time a stability-indicating HPLC-Corona CAD method for content determination of Artesunate (AS) and Mefloquine hydrochloride (MQ) in coated tablets 100 + 220 mg (ASMQ) developed by Farmanguinhos-Fiocruz. The chromatographic separation was carried out on two Promosil C18 columns in sequence. Chromatography was done using 0.05% formic acid/acetonitrile (80:20) in gradient at flow rate of 1 mL min?1, flow 0.6 mL/min for the right pump, and 0.3 mL/min for the left pump (acetonitrile 100%). The temperature was set at 25 °C for the oven and the detection. The elution time of AS and MQ was found to be 40.5 ± 0.5 min and 10.5 ± 0.5, respectively. The method was validated for system suitability, selectivity, linearity, precision, accuracy, and robustness. The forced degradation studies indicated that AS instability is the major trigger for product degradation, especially under heat and oxidative conditions. In conclusion, the method validation was in agreement with ICH guideline Q2(R1) and AOAC acceptance criteria. Our findings prospected the Corona-CAD detector as a quality control solution regarding the challenges of stability-indicating methods for fixed-dose products. 相似文献
30.
In this paper, a new fully automated scanning laser Doppler vibrometer (LDV) measurement technique is presented. In contrast to existing scanning LDV techniques which use a 2D camera for the manual selection of sample points, we use a 3D Time-of-Flight camera in combination with a CAD file of the test object to automatically obtain measurements at pre-defined locations. The proposed procedure allows users to test prototypes in a shorter time because physical measurement locations are determined without user interaction. Another benefit from this methodology is that it incorporates automatic mapping between a CAD model and the vibration measurements. This mapping can be used to visualize measurements directly on a 3D CAD model. The proposed method is illustrated with vibration measurements of an unmanned aerial vehicle 相似文献