低k氟化非晶碳层间介质对芯片性能的影响

讨论了通过合理设计的工艺流程将低k氟化非晶碳材料应用到制造工艺中作为互连介质对集成电路性能的影响。基于一个互连结构简化模型计算出采用低k氟化非晶碳材料作为互连介质后RC延迟、功率耗散和线间串扰的变化情况。采用低k氟化非晶碳介质后,RC延迟和功率耗散随着互连长度的增大而减小,线间串扰也得到显著抑制。     

Quantum-Chemical Evaluation of the Protolytic Properties of Thiophenols

The enthalpies and free energies of proton affinity (PA) were calculated by the PM3 method for 27 thiophenoxide anions. For thiophenols, linear correlation has been found between the PAs and the values of pK _a measured by different authors in aqueous acetone, aqueous ethanol, and methanol media. The dependences found permit one to predict a priori the protolytic properties of thiophenols. The differential effects of aqueous ethanol media with different ethanol contents on thiophenol acidity were evaluated based on quantum-chemical data.Original Russian Text Copyright © 2004 by A. N. Pankratov and A. V. Shalabai__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 800–806, September–October, 2004.     

The Rate Constant for Dissociative Electron Attachment to Ozone Revisited

The rate constant for dissociative electron attachment to ozone has been derived over the energy range from about 0 to 10 eV using recently measured and also corrected cross section data. The new rate constant data sets for two partial dissociative channels, as well as for the total dissociative electron attachment, are compared with previously reported values, and existing discrepancies are discussed.     

The Cosmological Constant in the Framework of Gravito-Magnetodynamic Waves in Weak Gravitational Fields

Using the linearization of Einstein's equations for weak gravitational fields, a specific model of gravito-magnetofluid is elaborated. The study of wave formation and propagation in such a medium is necessarily connected to the existence of the cosmological constant.     

Constants of Motion for Several One-Dimensional Systems and Problems Associated with Getting Their Hamiltonians

The constants of motion of the following systems are deduced: a relativistic particle with linear dissipation; a no-relativistic particle with a time explicitly depending force; a no-relativistic particle with a constant force and time depending mass; and a relativistic particle under a conservative force with position depending mass. The Hamiltonian for these systems, which is determined by getting the velocity as a function of position and generalized linear momentum, can be found explicitly at first approximation for the first system. The Hamiltonians for the other systems are kept implicitly in their expressions for their constants of motion.     

Techniques and Apparatus for Measuring Rotational Core Losses of Soft Magnetic Materials

In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.     

常曲率空间中单形的中面公式及其应用

本文给出了n维常曲率空间中单形的中面面积公式，利用它我们还得到了一类几何不等式．     

Synthesis and characterization of novel polyimides with 2,2‐bis[4(4‐aminophenoxy)phenyl]phthalein‐3′,5′‐bis(trifluoromethyl)anilide

2,2‐Bis[4(4‐aminophenoxy)phenyl]phthalein‐3′,5′‐bis(trifluoromethyl)anilide (6FADAP), containing fluorine and phthalimide moieties, was synthesized via the Williamson ether condensation reaction from 1‐chloro‐4‐nitrobenzene and phenolphthalein‐3′,5′‐bis(trifluoromethyl)anilide, which was followed by hydrogenation. Monomers such as 2,2‐bis[4(4‐aminophenoxy)phenyl]phthalein‐anilide containing phthalimide groups and 2,2‐bis[4(4‐aminophenoxy)phenyl]phthalein containing only phthalein moieties were also synthesized for comparison. The monomers were first characterized by Fourier transform infrared (FTIR), ¹H NMR, ¹⁹F NMR, elemental analysis, and titration and were then used to prepare polyimides with 2,2‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride. The polyimides were designed to have molecular weights of 20,000 g/mol via off‐stoichiometry and were characterized by FTIR, NMR, gel permeation chromatography (GPC), differential scanning calorimetry, and thermogravimetric analysis. Their solubility, water absorption, dielectric constant, and refractive index were also evaluated. The polyimides prepared with 6FADAP, containing fluorine and phthalimide moieties, had excellent solubility in N‐methylpyrrolidinone, N,N‐dimethylacetamide, tetrahydrofuran, CHCl₃, tetrachloroethane, and acetone, and GPC analysis showed a molecular weight of 18,700 g/mol. The polyimides also exhibited a high glass‐transition temperature (290 °C), good thermal stability (～500 °C in air), low water absorption (1.9 wt %), a low dielectric constant (2.81), a low refractive index, and low birefringence (0.0041). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3361–3374, 2003     

Rigorous results in selection of steady needle crystals

This paper concerns the existence of solutions to a steady needle crystal growth problem in a one-sided model. We rigorously prove that for small nonzero anisotropy γ, analytic symmetric needle crystal solutions exist in the limit of surface tension ε² if only if the stokes constant S for a relatively simple nonlinear differential equation is zero. This Stokes constant S depends on the parameter β=2^9/7γε^−8/7 and earlier numerical calculations by a number of investigators have shown this to be zero for a discrete set of values of β. It is also proven that for γ=0, there can be no symmetric needle crystal solution in the considered space.The methodology consists of two steps. First, the original problem is reduced to a weak half-strip problem for any γ in a compact set of [0,1) by relaxation of the symmetry condition. The weak problem is shown to have a unique solution in the function space considered for any γ∈[0,γ_m] for some γ_m>0. When a symmetry is invoked, the weak problem is shown equivalent to the original needle crystal problem. Next, by considering the behavior of the solution in neighborhood of an appropriate complex turning point for γ∈(0,γ_m], we extract an exponentially small term in ε as ε→0⁺ that generally violates the symmetric condition. We prove that the symmetry condition is satisfied for small ε when the parameter β is constrained appropriately.