Realization of a large J_2 quasi-2D spin-half Heisenberg system: Li2VOSiO4

Exchange couplings are calculated for Li2VOSiO4 using LDA. While the sum of in-plane couplings J_1 + J_2 = 9.5 \pm 1.5 K and the inter-plane coupling J_{perp} \sim 0.2 - 0.3 K agree with recent experimental data, the ratio J_2/J_1 \sim 12 exceeds the reported value by an order of magnitude. Using geometrical considerations, high temperature expansions and perturbative mean field theory, we show that the LDA derived exchange constants lead to a remarkably accurate description of the properties of these materials including specific heat, susceptibility, Neel temperature and NMR spectra.Comment: 4 two-column pages, 4 embedded postscript figure

Cycles with consecutive odd lengths

It is proved that there exists an absolute constant c > 0 such that for every natural number k, every non-bipartite 2-connected graph with average degree at least ck contains k cycles with consecutive odd lengths. This implies the existence of the absolute constant d > 0 that every non-bipartite 2-connected graph with minimum degree at least dk contains cycles of all lengths modulo k, thus providing an answer (in a strong form) to a question of Thomassen. Both results are sharp up to the constant factors.Comment: 7 page

Nilpotency Indices of the Radicals of Finite p-Solvable Group Algebras, IV

In [2], we have classified the p-solvable groups G with pm{ 2<t(G)<pm{ 1 for p odd, where t(G) is the nilpotency index of the (Jacobson) radical of k[G], k a field of characteristic p, and pm is the highest power of p dividing the order of G. In the paper cited above, we have given only an outline of the proof of the result for p = 3 ([2, Theorem 11]). To complete the proof of the theorem, we need somewhat complicated calculation, and we have given in [3] and [4] two parts of such calculations. The aim of this paper is to give one more such calculation and complete the proof of the theorem.Article信州大学理学部紀要 36(1): 9-28(2001)departmental bulletin pape

Regional Variety of Biotechnology Development in Asia

AbstractToday's biotechnology is widely regarded as a one of the most important sectors of the technology, a new wave of knowledge- based economy. It is characterized by innovation and a very fast pace of development, which is connected with the involvement of highly qualified specialists, research centers, varied sources of information, investments, as well as interconnections to guarantee the flow of information. Potentially, biotechnology has a wide range of applications, such as the food industry, production of genetically modified organisms, pharmaceutics, healthcare, detergents and bioremediation, forestry and agriculture. There is a huge variety in the world when it comes to the structure and space where the biotech development occurs. According to the collected data, there is an obvious dominant role of highly developed countries such as the United States and European countries: the UK, Germany, Switzerland, Italy and Sweden as well as Canada. Nevertheless the dynamic expansion of biotechnology occurs in new centers of biotech development in eastern European countries such as Lithuania and Slovakia as well as in Asian countries, including Turkey, India, South Korea and Japan. Furthermore, biotech development is determined by several factors. A distance from scientific centers, location of universities, financial sources and international cooperation must be taken into consideration. Country policies also come as the major determinants. With the Internet and common access to a very sophisticated piece of information and a very fast-developing technology, it's even easier for the biotech to make a step forward

Evolution of 4 pi observables in the Vlasov-Uehling-Uhlenbeck theory and the transverse momentum transfer as a barometer for hadronic matter

We study the dynamics of high energy heavy ion collisions through the Vlasov-Uehling-Uhlenbeck approach. Equilibration is observed, for central collisions. It is shown that the produced entropy, the pion multiplicity, flow angle, and transverse momentum distributions saturate at the moment of maximum compression and temperature. The effects of the nuclear equation of state and the Pauli principle are investigated. For the flow angle distribution there is a 20 deg reduction of the peak flow angle due to the Pauli principle. A stiff equation of state results in a 10–20 deg increase over the soft equation of state at all energies. The transverse momentum at projectile rapidity exhibits a peak structure as a function of impact parameter b. A 40% difference between soft and hard equation of state is observed for the peak impact parameter, i.e., for intermediate multiplicities