适用于亚微米沟道MO SFET的阈值电压解析模型

本文利用本征函数方法,采取一定的边界条件,得到了二维泊松方程的解析解.并由此导得适用于亚微米沟道MOS场效应管阈值电压的解析表达式.本解析模型未引进复杂的几何结构参数及经验参数,适用于不同的衬底反偏电压、漏极电压等条件.这些结果与数值模拟的结果以及有关实验的结果符合得较好,对短沟道MOSFET的设计及性能的了解有实际参考价值.     

Experimental study of the time-dependent rate of K → πππ

The time-dependence of the decay rate of initially pure K⁰ into the final state (π+</sup>π−</sup>π0</sup>) has been studied in search for the decay k_S0</sup>→π+</sup>π−</sup>π0</sup>. No evidence is found in a sample of 384 observed events. The ratio of the CP -violating K_S0</sup> amplitude and the K_L0</sup> amplitude is η₊₋₀ = (0.13_−0.20+0.17</sup>) + i(0.17_−0.26+0.27</sup>); the ratio of the CP-conserving K_S0</sup> amplitude and the K_L0</sup> amplitude is < 0.4. The energy dependence of the K0</sup>→π+</sup>π−</sup>π0</sup> matrix element is found to be a₊₋₀ = −0.31 ± 0.03.</sup>     

Numerical comparison of reaction-matrix and Jastrow methods for nuclear matter

The ground-state energy per particle of symmetrical nuclear matter has been calculated as a function of Fermi wave number for two representative central potentials containing hard cores, by means of both reaction-matrix and Jastrow methods. The agreement of results from the two methods is remarkably good in the density region near equilibrium.     

Pb decay and M4 transition probabilities in neutron-deficient lead isotopes

The decay of 6.1 sec ^203mPb has been examined with a high-resolution Ge(Li) spectrometer, and a 5.1 keV M2 transition was found to compete with the 825.2 keV M4 isometric transition. The M4 transition probability, thus corrected, is now found to be consistent with those of the other M4 transitions in the lead region.</sup>     

Dynamical consequences of spontaneous breakdown of symmetries

The spontaneous breakdown of a continuous symmetry group generated by conserved currents is considered. In the framework of general quantum field theory the possible dynamical consequences of spontaneous breakdown are analysed: a general relation is derived between n− and (n+1) — point functions involving Goldstone bosons in the limit of zero momentum. The technique is illustrated by a few examples for the SU(2) × SU(2) chiral group and the results generalized relations known from the perturbative treatment of the σ-model.     

Vanishing line for the descent spectral sequence

We prove that if $f:X \to Y$ is a surjective, cohomologically (k - 1)-connected and proper map between locally compact spaces, then for the cohomological descent spectral sequence one has $E^{pq}_{2} = 0$ provided $q < pk$.     

Reduction of spin glasses applied to the Migdal-Kadanoff hierarchical lattice

A reduction procedure to obtain ground states of spin glasses on sparse graphs is developed and tested on the hierarchical lattice associated with the Migdal-Kadanoff approximation for low-dimensional lattices. While more generally applicable, these rules here lead to a complete reduction of the lattice. The stiffness exponent governing the scaling of the defect energy E with system size L, (E) ~L ^y, is obtained as y ₃ = 0.25546(3) by reducing the equivalent of lattices up to L = 2100</sup> in d = 3, and as y ₄ = 0.76382(4) for up to L = 235</sup> in d = 4. The reduction rules allow the exact determination of the ground state energy, entropy, and also provide an approximation to the overlap distribution. With these methods, some well-know and some new features of diluted hierarchical lattices are calculated.</sup>     

A semi-deterministic propagation model for predicting short-term fading statistics in urban environments based on the Nakagami-m distribution

In this paper, a semi-deterministic propagation model for predicting short-term fading statistics in urban environments is presented. An approach to include surface scattering into deterministic ray-optical propagation models in urban scenarios is derived. This approach considers the coherent and incoherent components of the scattered signal. A statistical characterisation of the received signal at the received position permits to model the short-term fading for a local area around the mobile position using the Nakagami-m distribution. The parameters of the Nakagami-m distribution are obtained taking into account the real environment from a digital map information of the urban area. Computer simulation results and experimental data are compared.