排序方式: 共有42条查询结果,搜索用时 15 毫秒
1.
Compound‐specific amino acid δ15N values in archaeological shell: Assessing diagenetic integrity and potential for isotopic baseline reconstruction 下载免费PDF全文
2.
Colson S Konczykowski M Gaifullin MB Matsuda Y Gierłowski P Li M Kes PH Van Der Beek CJ 《Physical review letters》2003,90(13):137002
Vortex thermal fluctuations in heavily underdoped Bi(2)Sr(2)CaCu(2)O(8+delta) (T(c)=69.4 K) are studied using Josephson plasma resonance. From the zero-field data, we obtain the c-axis penetration depth lambda(L,c)(0)=230+/-10 micrometer and the anisotropy ratio gamma(T). The low plasma frequency allows us to study phase correlations over the whole vortex solid state and to extract a wandering length r(w) of vortex pancakes. The temperature dependence of r(w) as well as its increase with dc magnetic field is explained by the renormalization of the vortex line tension by the fluctuations, suggesting that this softening is responsible for the dissociation of the vortices at the first order transition. 相似文献
3.
It is shown that solvable mixed spin ladder models can be constructed from su(N) permutators. Heisenberg rung interactions appear as chemical potential terms in the Bethe Ansatz solution. Explicit examples given are a mixed spin-
spin-1 ladder, a mixed spin-
spin-
ladder and a spin-1 ladder with biquadratic interactions. 相似文献
4.
A two-dimensional steady-sate analysis of semi-infinite brittlecrack growth at a constant subcritical rate in an unboundedfully-coupled thermoelastic solid under mixed-mode thermomechanicalloading is made. The loading consists of normal and shear tractionsand heat fluxes applied as point sources (line loads in theout-of-plane direction). A related problem is solved exactly in an integral transformspace, and robust asymptotic forms used to reduce the originalproblem to a set of integral equations. The equations are partiallycoupled and exhibit operators of both Cauchy and Abel types,yet can be solved analytically. The temperature change field at a distance from the moving crackedge is then constructed, and its dominant term is found tobe controlled by the imposed heat fluxes. The role of this termis, indeed, enhanced if the heat fluxes serve to render thecrack as a net heat source/sink for the solid, as opposed tobeing a transmitter of heat across its plane. More generally,the influence of the thermoelastic coupling on this field, aswell as other functions, is found to increase with crack speed. 相似文献
5.
6.
Nicholas R. Beaton Mireille Bousquet-Mélou Jan de Gier Hugo Duminil-Copin Anthony J. Guttmann 《Communications in Mathematical Physics》2014,326(3):727-754
In 2010, Duminil-Copin and Smirnov proved a long-standing conjecture of Nienhuis, made in 1982, that the growth constant of self-avoiding walks on the hexagonal (a.k.a. honeycomb) lattice is ${\mu=\sqrt{2+\sqrt{2}}}$ . A key identity used in that proof was later generalised by Smirnov so as to apply to a general O(n) loop model with ${n\in [-2,2]}$ (the case n = 0 corresponding to self-avoiding walks). We modify this model by restricting to a half-plane and introducing a surface fugacity y associated with boundary sites (also called surface sites), and obtain a generalisation of Smirnov’s identity. The critical value of the surface fugacity was conjectured by Batchelor and Yung in 1995 to be ${y_{\rm c}=1+2/\sqrt{2-n}}$ . This value plays a crucial role in our generalized identity, just as the value of the growth constant did in Smirnov’s identity. For the case n = 0, corresponding to self-avoiding walks interacting with a surface, we prove the conjectured value of the critical surface fugacity. A crucial part of the proof involves demonstrating that the generating function of self-avoiding bridges of height T, taken at its critical point 1/μ, tends to 0 as T increases, as predicted from SLE theory. 相似文献
7.
V.D. Okunev Z.A. Samoilenko E.I. Pushenko R. Szymczak P. Gier?owski I.A. Antoshina 《Applied Surface Science》2008,254(11):3469-3478
The nature of grey spots on the surface of amorphous Fe67Cr18B15 metglass ribbons irradiated by 30 keV Ar+ ions is investigated. Changes in the surface and volume properties of samples are analyzed bearing in mind the presence of competitive processes of ordering and disordering in the structure under irradiation at initial stage of crystallization (T = 500 °C). Changes in the volume properties of the samples become apparent in their structure, electrical and magnetic properties and are caused by radiation-enhanced diffusion at high gradients in the concentration of defects generated by Ar+ irradiation. It is established that grey spots are shown by decrease in the reflection coefficient in a visible range. They emerge as a result of reorganization in the electronic structure of irradiated ribbons due to damage in the short-range order and formation of non-uniformly scaled atomic structure during transition from the medium-range to the long-range atomic order. Experimental data are in accord with the calculations in the framework of the free electrons model. 相似文献
8.
Baeva M. Gier H. Pott A. Uhlenbusch J. Höschele J. Steinwandel J. 《Plasma Chemistry and Plasma Processing》2001,21(2):225-247
Pulsed microwave discharges operated at atmospheric pressure in gas mixtures containing N2, O2, and NO are investigated experimentally and theoretically for various gas mixture constituents and operating conditions with respect to the ability of exhaust gas purification. The rotational gas temperature and the vibrational temperature of N2 are derived from CARS measurements. The composition of the exhaust gas after treatment is monitored using FTIR spectroscopy. The processes of the chemical, electronic, and vibrational kinetics are described by a model that has been developed to calculate the species densities. The results obtained show that in N2/NO gas mixtures an overall reduction of NOx takes place. In the case of N2/O2/NO gas mixtures, no net reduction of NOx is achieved for a pulsed microwave power below 3600 W, a pulse length of 50 s, and a typical repetition frequency of 2 kHz. 相似文献
9.
10.
Amita Gupta Alexei Yu Ganin Parmanand Sharma Vikrant Agnihotri LM Belova KV Rao Mikhail E Kozlov AA Zakhidov RH Baughman 《Pramana》2002,58(5-6):1051-1059
We present studies of novel nanocomposites of BiNi impregnated into the structure of opals as well as inverse opals. Atomic force microscopy and high resolution elemental analyses show
a highly ordered structure and uniform distribution of the BiNi filler in the matrix. These BiNi-based nanocomposites are
found to exhibit distinct ferromagnetic-like ordering with transition temperature of about 675 K. As far as we know there
exists no report in literature on any BiNi compound which is magnetic. 相似文献