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排序方式: 共有180条查询结果,搜索用时 140 毫秒
51.
Keya Zhang Kathryn M. Nelson Karan Bhuripanyo Kimberly D. Grimes Bo Zhao Courtney C. Aldrich Jun Yin 《Chemistry & biology》2013,20(1):92-101
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52.
A. Ghose Choudhury A. Roy Chowdhury 《International Journal of Theoretical Physics》1994,33(10):2031-2036
The role of nonlocal conservation laws and the corresponding charges are analyzed in the supersymmetric Heisenberg spin chain. It is observed that such nonlocal charges generate a graded-Yangian type algebra, by using the properties of the monodromy matrix and classicalr matrix. 相似文献
53.
Jeong Seok Oh Sayata Ghose A. I. Isayev 《Journal of Polymer Science.Polymer Physics》2003,41(22):2959-2968
The ultrasonic treatment of unfilled butadiene rubber (BR) gum with a grooved‐barrel ultrasonic reactor was carried out, leading to changes in the structure and physical properties. The ultrasonic treatment of BR gum led to gel formation, with the amount dependent on the amplitude. The rheological and mechanical properties of the ultrasonically treated samples and their vulcanizates were measured and compared with those of the virgin samples. Gel permeation chromatography measurements of the sol part of the virgin and the treated samples were carried out. Rheological property and molecular weight measurements indicated the creation of a branched structure and the occurrence of degradation in ultrasonically treated BR gum. Because of degradation, the tensile strength and Young's modulus of treated BR were lower than those of untreated BR, whereas the elongation at break was practically intact. Differential scanning calorimetry (DSC) curves at a high‐temperature range showed exothermic peaks with enthalpy reduction in the treated BR, indicating a decrease in the number of double bonds due to gel formation. DSC curves at a low‐temperature range indicated increased crystallinity in the treated samples. Competing reactions of gel formation, branching, and degradation occurred during the ultrasonic treatment. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2959–2968, 2003 相似文献
54.
Partha Ghose 《Pramana》2002,59(2):417-424
It is shown that conventional de Broglie-Bohm quantum theory is incompatible with the standard quantum theory of a system
unless the former is ergodic. 相似文献
55.
Fabrication and testing of a newly designed slit system for depth‐resolved X‐ray diffraction measurements
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John Sinsheimer Nathalie Bouet Sanjit Ghose Eric Dooryhee Ray Conley 《Journal of synchrotron radiation》2016,23(6):1296-1304
A new system of slits called `spiderweb slits' have been developed for depth‐resolved powder or polycrystalline X‐ray diffraction measurements. The slits act on diffracted X‐rays to select a particular gauge volume of sample, while absorbing diffracted X‐rays from outside of this volume. Although the slit geometry is to some extent similar to that of previously developed conical slits or spiral slits, this new design has advantages over the previous ones in use for complex heterogeneous materials and in situ and operando diffraction measurements. For example, the slits can measure a majority of any diffraction cone for any polycrystalline material, over a continuous range of diffraction angles, and work for X‐ray energies of tens to hundreds of kiloelectronvolts. The design is generated and optimized using ray‐tracing simulations, and fabricated through laser micromachining. The first prototype was successfully tested at the X17A beamline at the National Synchrotron Light Source, and shows similar performance to simulations, demonstrating gauge volume selection for standard powders, for all diffraction peaks over angles of 2–10°. A similar, but improved, design will be implemented at the X‐ray Powder Diffraction beamline at the National Synchrotron Light Source II. 相似文献
56.
The sonar beam of an echolocating bat forms a spatial window restricting the echo information returned from the environment. Investigating the shape and orientation of the sonar beam produced by a bat as it flies and performs various behavioral tasks may yield insight into the operation of its sonar system. This paper presents recordings of vertical and horizontal cross sections of the sonar beam produced by Eptesicus fuscus (big brown bats) as they fly and pursue prey in a laboratory flight room. In the horizontal plane the sonar beam consists of one large lobe and in the vertical plane the beam consists of two lobes of comparable size oriented frontally and ventrally. In level flight, the bat directs its beam such that the ventral lobe is pointed forward and down toward the ground ahead of its flight path. The bat may utilize the downward directed lobe to measure altitude without the need for vertical head movements. 相似文献
57.
Anindya Ghose Choudhury 《Central European Journal of Physics》2013,11(1):49-58
In this communication we study a class of one parameter dependent auto-Bäcklund transformations for the first flow of the relativistic Toda lattice and also a variant of the usual Toda lattice equation. It is shown that starting from the Hamiltonian formalism such transformations are canonical in nature with a well defined generating function. The notion of spectrality is also analyzed and the separation variables are explicitly constructed. 相似文献
58.
H. Chaudhuri C. Barman A. N. S. Iyengar D. Ghose P. Sen B. Sinha 《The European physical journal. Special topics》2013,222(3-4):827-838
Research on earthquake prediction has drawn serious attention of the geophysicist, geologist and investigators in different fields of science across the globe for many decades. Researchers around the world are actively working on recording pre-earthquake changes in non-seismic parameters through a variety of methods that include anomalous changes in geochemical parameters of the Earth’s crust, geophysical properties of the lithosphere as well as ionosphere etc. Several works also have been done in India to detect earthquake precursor signals using geochemical and geophysical methods. However, very few works have been done so far in India in this field through the application of nonlinear techniques to the recorded geophysical and geochemical precursory signals for earthquakes. The present paper deals with a short review of the early works on geochemical precursors that have been carried out in India as yet. With a view to detect earthquake precursory signals by means of gas-geochemical method we developed a network of seismo-geochemical monitoring observatories in India in hot springs and mud volcano crater. In the last few years we detected several geochemical anomalies and those were observed prior to some major earthquakes that occurred within a radius of 1500?km from the test sites. In the present paper we have applied nonlinear techniques to the long term, real-time and natural data sets of radon-222 and associated gamma originated out of the terrestrial degassing process of the earth. The results reveal a clear signature of the long range correlation present in the geochemical time series. This approach appears to be a potential tool to explore intrinsic information hidden within the earthquake precursory signals. 相似文献
59.
It is known that Jacobi’s last multiplier is directly connected to the deduction of a Lagrangian via Rao’s formula (Madhava
Rao in Proc. Benaras Math. Soc. (N.S.) 2:53–59, 1940). In this paper we explicitly demonstrate that it also plays an important role in Hamiltonian theory. In particular, we apply
the recent results obtained by Torres del Castillo (J. Phys. A Math. Theor. 43:265202, 2009) and deduce the Hamiltonian of a second-order ODE of the Lienard type, namely, [(x)\ddot]+f(x)[(x)\dot]2+g(x)=0\ddot{x}+f(x){\dot{x}}^{2}+g(x)=0. In addition, we consider cases where the coefficient functions may also depend on the independent variable t. We illustrate our construction with various examples taken from astrophysics, cosmology and the Painlevé-Gambier class of
differential equations. Finally we discuss the Hamiltonization of third-order equations using Nambu-Hamiltonian mechanics. 相似文献
60.
Bo Zhao Karan Bhuripanyo Keya Zhang Hiroaki Kiyokawa Hermann Schindelin Jun Yin 《Chemistry & biology》2012,19(10):1265-1277
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