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991.
An approach of three-dimensional seismic ray tracing is presented, which is derived from adopting two-dimensional linear traveltime
interpolation (LTI). By adjusting the forward process using the partition of grid interface, and backward step by considering
more directions, the new approach is suitable for the application of three-dimensional models. The calculation results show
that, with the same accuracy, the improved 3-D method is much faster than the method of traditional LTI directly applied in
the three-dimensional case. 相似文献
992.
To investigate the feasibility of using complex networks in the study of linguistic typology, this paper builds and explores 15 lin-guistic complex networks based on the dependency syntactic treebanks of 15 languages. The results show that it is possible to classify human languages by means of the following main parameters of complex networks: (a) average degree of the node, (b) cluster coefficients, (c) average path length, (d) network centralization, (e) diameter, (f) power exponent of degree distribution, and (g) the determination coefficient of power law distributions. The precision of this method is similar to the results achieved by means of modern word order typology. This paper tries to solve two problems of current linguistic typology. First, the language sample of a typological study is not real text; second, typological studies pay too much attention to local language structures in the course of choosing typological parameters. This study performs better in global typological features of language and not only enhances typological methods, but it is also valuable for developing the applications of complex networks in the humanities, social, and life sciences. 相似文献
993.
Flavin-containing monooxygenase (FMO), like cytochrome P450 (CYP), is a monooxygenase that uses the reducing equivalents of NADPH to reduce one atom of molecular oxygen to water, while the other atom is used to oxidize the substrate. Recently, it was shown that some CYP isoforms have been subject to positive selection. However, it is unknown whether the highly conserved phase I detoxification enzyme, FMO, has undergone similar positive Darwinian selection. We used maximum-likelihood models of codon substitution, evolutionary fingerprinting, and cross species comparison to investigate the occurrence of adaptive evolution in FMO sequences. We used recent genomic data from a range of species, including vertebrates and invertebrates. We present the evidence for the occurrence of adaptive evolution in mammalian FMO 3, 4, 5, and fugu FMOs but not in mammalian FMO 1, FMO 2, frog FMOs, other fish FMOs and invertebrate FMOs. The sites under adaptive evolution were significantly associated with the insertion domain in mammalian FMO 5. We identified specific amino acid sites in FMOs 3–5 that are likely targets for selection based on the patterns of parallel amino acid change. The most likely role of adaptive evolution is the repair of mutations that permitted optimal NADP+ binding and improved catalytic efficiency. The occurrence of positive selection during the evolution of phase I detoxification enzymes such as FMOs 3–5 and fugu FMO suggests the occurrence of both high selection pressure acting on species within their unique habitats and significant changes in intensity and direction (forms of xenobiotics and drugs) resulting from changes in microhabitat and food. 相似文献
994.
Gold nanoshells (GNSs), consisting of a dielectric core coated with gold, have gained extensive attention as they show readily tunable optical properties and good biocompatibility. As highly sensitive and label-free optical biosensors with wide applications, GNSs have been investigated in many fields including drug delivery, immunoassay, cancer treatment, biological sensing and imaging. Taking advantage of the adjustability of the local surface plasmon resonance (LSPR) and the sensitivity of the surfaceenhanced Raman scattering (SERS) signal of GNSs, we have developed diverse applications including plasmonic biosensors and nanoprobes based on GNSs. In this review we introduce plasmonic and electromagnetic properties and fabrication methods of GNSs. We describe research progress in recent years, and highlight several applications of GNSs developed by our group. Finally we provide a brief assessment of future development of GNSs as plasmonic materials that can be integrated with complementary analytical techniques. 相似文献
995.
本文通过对两组学生两次考试成绩进行分析,并对学生和老师进行问卷调查和座谈,证明:在高职高专医学专业工学结合模式下儿科临床教学的改革中,只有早期接触临床、采用工学结合的教育模式、不断提高临床教师教学水平,才能更好地适应医学高职教育的需要,培养面向基层的高素质实用型卫生人才. 相似文献
996.
997.
Earthquake may cause severe damage to all kinds of bridge such as the falling down of the girder; therefore,effective measures should be employed to control the seismic displacement. In this paper,the method of comprehensive optimal control,com-bined with analytic hierarchy process,is employed to investigate the seismic response control of the Nanjing Jiangxinzhou Bridge,which is a single-tower self-anchored suspension bridge (SSSB). Also,3-dimensional nonlinear seismic response analyses are con-ducted. Three types of practical connection measures for seismic response control of SSSB are investigated,and the optimal pa-rameters of the connection devices are achieved by this method. Results show that both the elastic connection devices and the damp-ers with rational parameters can reduce the seismic displacement of the bridge effectively,but the elastic connection devices will in-crease the seismic force of the tower. When all factors are consid-ered,the optimal measure is by using the elastic connection devices and the dampers together. These results can provide references for seismic response control of SSSBs. 相似文献
998.
999.
Ying Gao 《系统科学与复杂性》2011,24(3):593-603
This paper consider Hexagonal-metric codes over certain class of finite fields. The Hexagonal metric as defined by Huber is
a non-trivial metric over certain classes of finite fields. Hexagonal-metric codes are applied in coded modulation scheme
based on hexagonal-like signal constellations. Since the development of tight bounds for error correcting codes using new
distance is a research problem, the purpose of this note is to generalize the Plotkin bound for linear codes over finite fields
equipped with the Hexagonal metric. By means of a two-step method, the author presents a geometric method to construct finite
signal constellations from quotient lattices associated to the rings of Eisenstein-Jacobi (EJ) integers and their prime ideals
and thus naturally label the constellation points by elements of a finite field. The Plotkin bound is derived from simple
computing on the geometric figure of a finite field. 相似文献
1000.
现实银行网点的布局存在一定的不合理性,利用复杂网络的方法,首先提出了一种基于复杂网络的银行网点布局和网点优化模型;接着对模型进行了分析并与相关研究方法进行了对比;最后利用该模型对太原市农业银行网点布局进行了研究和网点布局调整,得到较为合理的网点布局. 相似文献