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61.
62.
To study the spatial difference of ocean ambient noise in offshore China and reveal its generation mechanism, the difference between the noise level(NL) of two stations is compared based on long-term observation data collected in the same season. Considering the influence of underwater acoustic channels and the characteristics of noise sources, the transmission loss level(TL) from the port ship noise sources to the measuring station is analyzed and it shows a strong correlation between the transmission loss difference(TLD) and noise level difference(NLD) at the band of 50-500 Hz. At the same time, the analysis of ship noise source level(SL) presents a difference about 20 dB between the two ports, corresponding to the variation of the ship density before and during the fishing moratorium. The results prove that the ambient noise is closely related to ship noise sources at this frequency band, and the noise difference between the two stations results from the transmission loss and the ship noise sources. 相似文献
63.
Nonlinear Dynamics - The prime concern of this study is to simulate the joint effect for the presence of two fractional derivative parameters (memory indices) by providing a novel analytical... 相似文献
64.
A graph G is loosely-c-connected, or ?-c-connected, if there exists a number d depending on G such that the deletion of fewer than c vertices from G leaves precisely one infinite component and a graph containing at most d vertices. In this paper, we give the structure of a set of ?-c-connected infinite graphs that form an unavoidable set among the topological minors of ?-c-connected infinite graphs. Corresponding results for minors and parallel minors are also obtained. 相似文献
65.
As in earlier works, we consider {0,1}n as a sample space with a probability measure on it, thus making pseudo-Boolean functions into random variables. Under the assumption that the coordinate random variables are independent, we show it is very easy to give an orthonormal basis for the space of pseudo-Boolean random variables of degree at most k. We use this orthonormal basis to find the transform of a given pseudo-Boolean random variable and to answer various least squares minimization questions. 相似文献
66.
Guoli Zheng Weiqiang Fan Shuyan Song Huadong Guo HongJie Zhang 《Journal of solid state chemistry》2010,183(6):1457-545
Reaction of sodium p-sulfonatocalix[4]arene and TbCl3 in the presence of 2,2′-bipyridine-N,N′-dioxide (bpdo) gives the 2:1 supramolecular nanocapsule [[Tb(bpdo)2·4H2O]3+?{p-sulfonatocalix[4]arene4−}2], which further interacts with the [Tb(bpdo)4]3+ through charge-assisted π-stacking interactions forming a channel structure 1. In further investigation, we tried to use the terpyridine-1,1′,1′-trisoxide (tpto) instead of bpdo. Although we failed to isolate a supramolecular capsules based on the tpto, lanthanide and p-sulfonatocalix[4]arene, a layer structure derived from p-sulfonatocalix[4]arene with an unusual [Cu(tpto)2]2+ incorporation into the cavity of the calixarene and an outside [Cu(tpto)2]2+ balancing the charge, has been obtained. Fluorescence spectra show clearly that compound 1 possesses the luminescence characteristics of Tb3+ and the ligand bpdo can sensitize Tb3+ ion. Gas sorption experiment shows the channel structure 1 has highly selective gas sorption properties for water and methanol. 相似文献
67.
本文以四间甲苯硼酸根用作新阴离子缔合剂,并以与马钱子碱形成的离子缔合物作活性物质,代替文献中的苦酮酸-马钱子碱装制电极。电极对马钱子碱响应的线性范围为1×10-2-5×10-6M,检测下限可达1×10-6M,对毛果云香碱、阿托品和辛可宁等生物碱的选择性系数及响应时间等性能,均比文献报导为佳。 相似文献
68.
水杨醛二缩邻苯二胺汞(Ⅱ)配合物为载体的高选择性碘离子电极的研究 总被引:2,自引:0,他引:2
研究了希夫碱金属「Co(Ⅱ)、Mn(Ⅱ)、Zn(Ⅱ)、Hg(Ⅱ)」配合物为载体的阴离子选择性电极,结果表明,水杨醛二缩邻苯二胺汞对碘离子具有高的选择性,且电极呈现反Hofmeister行为,其选择性次序为:I〉SCH〉Br〉ClO4〉Cl〉NO2〉NO3〉SO4^2-。该电极响应速度快,具有良好的稳定性,使用寿命在三个月以上,用交流阻抗,紫外可见光谱技术研究了电极的响应机理并将电极用于药品分析,结 相似文献
69.
醋酸纤维膜固定过氧化氢酶电极的研究 总被引:1,自引:0,他引:1
本将过氧化氢酶与经活化处理的醋酸纤维膜共价固定,并与氧电极偶合,研制成静态和流通二种过氧化氢生物电极。研究了醋酸纤维膜的活化、酶的固定化、测试介质等有关的实验条件和参数。测得静态和流通二种电极响应的线性范围分别为6.7×10^-5 ̄2.0×10^-3mol/L和1.3×10^-4 ̄1.0×10^-3mol/L。将电极用于实际试样中的回收率测定时,获得了较好的结果。 相似文献
70.
We show that if G is a simple connected graph with and , then G has a spanning tree with > t leaves, and this is best possible. © 2001 John Wiley & Sons, Inc. J Graph Theory 37: 189–197, 2001 相似文献