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71.
应用影射法求解KdV方程,得到了KdV方程的物理上有意义的两种类型的行波解,即孤立波解和Jacobi椭圆函数解,并绘图加以说明. 相似文献
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航天立体测绘相机受卫星发射过程的振动、冲击以及复杂的空间环境的影响,相机的靶面将不同程度地偏离相机的焦平面,导致图像分辨率下降.对于测绘相机,其主点位置和主距变化量直接影响地面目标定位准确度.为了弥补利用编码器进行检焦的不足,提出了一种基于像散量的检调焦方法.该方法采用四象限光电探测器测量相机靶面变化引起的像散量,参照已标定的靶面位置与像散量之间的关系,计算出靶面偏离相机焦平面的实际大小和方向.这种检焦方法包含引起相机靶面离焦的所有因素,试验结果表明,基于像散法的测绘相机调焦机构的分辨率可达0.025 mm. 相似文献
75.
The effect of Al substitution for Fe on crystal structure, magnetostriction and spontaneous magnetostriction, anisotropy and spin reorientation of a series of polycrystalline Tb0.3Dy0.7(Fe1-xAlx)1.95 alloys (x = 0, 0.05, 0.1, 0.15, 0.20, 0.25, 0.30, 0.35) at room temperature and 77 K was investigated systematically. It was found that the primary phase of Tb0.3Dy0.7(Fe1-xAlx)1.95 is the MgCu2-type cubic Laves phase structure when x < 0.4 and the lattice constant a of Tb0.3Dy0.7(Fe1-xAlx)1.95 increases approximately and monotonically with the increase of x. The substitution of Al leads to the fact that the magnetostriction ( inceases slightly in a low magnetic field (H ≤ 40 kA/m), but decreases sharply and is easily close to saturation in a high applied field as x increases, showing that a small amount of Al substitution is beneficial to a decrease in the magnetocrystalline anisotropy. It was also found that the spontaneous magnetostriction (ζ)111 decreases greatly with x increasing. The analysis of the M(o)ssbauer spectra indicated that the easy magnetization direction in the {110} plane deviates slightly from the main axis of symmetry with the changes of composition and temperature, namely spin reorientation. A small amount of non-magnetic phase exists for x = 0.15 in Tb0.3Dy0.7(Fe1-xAlx)1.95 alloys and the alloys become paramagnetic for x > 0.15 at room temperture, but at 77 K the alloys still remain magnetic phase even for x = 0.2. At room temperature and 77 K, the hyperfine field decreases and the isomer shifts increase with Al concentration increasing. 相似文献
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77.
Marién Abreu Jan Goedgebeur Domenico Labbate Giuseppe Mazzuoccolo 《Journal of Graph Theory》2019,92(4):415-444
A -bisection of a bridgeless cubic graph is a -colouring of its vertex set such that the colour classes have the same cardinality and all connected components in the two subgraphs induced by the colour classes ( monochromatic components in what follows) have order at most . Ban and Linial Conjectured that every bridgeless cubic graph admits a -bisection except for the Petersen graph. A similar problem for the edge set of cubic graphs has been studied: Wormald conjectured that every cubic graph with has a -edge colouring such that the two monochromatic subgraphs are isomorphic linear forests (ie, a forest whose components are paths). Finally, Ando conjectured that every cubic graph admits a bisection such that the two induced monochromatic subgraphs are isomorphic. In this paper, we provide evidence of a strong relation of the conjectures of Ban-Linial and Wormald with Ando's Conjecture. Furthermore, we also give computational and theoretical evidence in their support. As a result, we pose some open problems stronger than the above-mentioned conjectures. Moreover, we prove Ban-Linial's Conjecture for cubic-cycle permutation graphs. As a by-product of studying -edge colourings of cubic graphs having linear forests as monochromatic components, we also give a negative answer to a problem posed by Jackson and Wormald about certain decompositions of cubic graphs into linear forests. 相似文献
78.
Cellular prion protein, a membrane protein, is expressed in all mammals. Prion protein is also found in human blood as an anchorless protein, and this protein form is one of the many potential sources of misfolded prion protein replication during transmission. Many studies have suggested that β-amyloid1–42 oligomer causes neurotoxicity associated with Alzheimer''s disease, which is mediated by the prion protein that acts as a receptor and regulates the hippocampal potentiation. The prevention of the binding of these proteins has been proposed as a possible preventative treatment for Alzheimer''s disease; therefore, a greater understanding of the binding hot-spots between the two molecules is necessary. In this study, the epitope mapping immunoassay was employed to characterize binding epitopes within the prion protein and complementary epitopes in β-amyloid. Residues 23–39 and 93–119 in the prion protein were involved in binding to β-amyloid1–40 and 1–42, and monomers of this protein interacted with prion protein residues 93–113 and 123–166. Furthermore, β-amyloid antibodies against the C-terminus detected bound β-amyloid1–42 at residues 23–40, 104–122 and 159–175. β-Amyloid epitopes necessary for the interaction with prion protein were not determined. In conclusion, charged clusters and hydrophobic regions of the prion protein were involved in binding to β-amyloid1–40 and 1–42. The 3D structure appears to be necessary for β-amyloid to interact with prion protein. In the future, these binding sites may be utilized for 3D structure modeling, as well as for the pharmaceutical intervention of Alzheimer''s disease. 相似文献
79.
以乙二醇、乙醇为溶剂通过溶剂热法制备出立方状ITO纳米粉体,研究了反应时间、NaOH浓度对ITO纳米粉体形貌的影响,并讨论了溶剂体积比、NaOH浓度对ITO粉体导电性的影响及机理。结果表明:采用乙二醇与乙醇做溶剂,VEG:VEtOH=4:1时,制备出分散性良好的立方状ITO纳米粉体,平均粒径为10.7 nm,且其XRD衍射峰强度比I400/I222最高为0.380;乙二醇与乙醇做溶剂,VEG:VEtOH=4:1,且NaOH浓度为0.275 mol·L-1时,粉体电导率最高为46.75 mS·cm-1。 相似文献
80.
Ionic liquid crystals based on ionic complexation of tris(2‐aminoethyl)amine (1) with 3,4,5‐tris(7,7,8,8,9,9,10,10,11,11,12,12,12‐tridecafluorododecyloxy)benzoic acid (2) and with 3,4,5‐tris(2‐octyldodecyloxy)benzoic acid (3) were investigated. The ionic complex with the partially fluorinated alkyl chains (1·2) exhibited a morphological transition from a hexagonal columnar mesophase to a Pm3n micellar cubic phase upon increasing the molar ratio of 2 to 1. For the complex with the branched alkyl chains (1·3) a micellar cubic mesophase was exclusively generated at appropriate composite ratios. The generation of the micellar cubic mesophases is attributed to the introduction of the laterally expanded volume of the alkyl chains compared with the corresponding normal dodecyl chains. Their thermal stabilities were most enhanced at a specific molar ratio of 1:5 for 1·2 and 1:4 for 1·3. This result corresponds to the most suitable chain volume for the stable micellar cubic mesophase. 相似文献