Test of the Zweig rule in π−p interactions at 19 GeV/c

We have observed φ production in π^?p interactions at 19 GeV/c with (44±10) events in the final state φπ⁺π^?π^?p and (45±9) events in φK⁺K^?π^?p. The production ratios φπ⁺π^?π^?p/ωπ⁺π^?π^?p ≈ 0.005 and φK⁺K^?π^?p/?°K⁺K^?π^?p ≈ 0.45 agree with Zweig-rule expectations.     

Optical and thermal properties of F and F aggregate centers in KF

A detailed investigation has been carried out of the optical and thermal properties of centers such as F, F_A, M and M_A in pure, Na-doped and Li-doped KF. Most centers exhibit properties which are qualitatively similar to those produced in other potassium halides with the notable exception of the F_A (Na) center, which has both Type I and Type II behavior.     

Elimination of on-axis waves in hologram formation using anisotropic centers in alkali halides

A technique is demonstrated for eliminating the on-axis waves from a reconstructed wavefront using reversible photodichroic crystals, i.e., alkali halide crystals with anisotropic color centers.     

Photochemically knocking out glutamate receptors in vivo

AMPA (alpha-amino-3-hydroxy-5-methyl-4-isooxazole) receptors, a major subtype of ionotropic glutamate receptors (iGluRs), mediate the majority of the fast communication between neurons, and the activity-dependent trafficking of AMPA receptors at synapses plays a role in mammalian learning and memory. Here we describe the design, synthesis, and evaluation of a photoreactive AMPA receptor antagonist that provides a means of "knocking out" AMPA receptors present on the surface of cells. The antagonist, 6-azido-7-nitro-1,4-dihydroquinoxaline-2,3-dione (ANQX), was designed by introducing a photoreactive azido group onto a quinoxalinedione inhibitor scaffold. Computational docking of ANQX to the AMPA receptor ligand-binding core predicted efficient binding to AMPA receptors. Glutamate-evoked currents were reversibly blocked at micromolar ANQX concentrations prior to photolysis and irreversibly blocked following photolysis. ANQX provides a means of directly evaluating the trafficking of native AMPA receptors with unparalleled spatiotemporal resolution.     

Evidence for two superconducting gaps in MgB2

We have measured the Raman spectra of polycrystalline MgB2 from 25 to 1200 cm(-1). A superconductivity-induced redistribution in the electronic Raman continuum was observed. Two pair-breaking peaks appear in the spectra, suggesting the presence of two superconducting gaps. The measured spectra were analyzed using a quasi-two-dimensional model in which two s-wave superconducting gaps open on two sheets of Fermi surface. For the gap values we have obtained Delta(1) = 22 cm(-1) ( 2.7 meV) and Delta(2) = 50 cm(-1) ( 6.2 meV). Our results suggest that a conventional phonon-mediated pairing mechanism occurs in the planar boron sigma bands and is responsible for the superconductivity of MgB2.     

一般n阶特征量泛函的Euler-Lagrange方程及与定量因果原理、相对性原理和广义牛顿三定律的统一

本文获得了有各种相互作用的一般n阶特征量泛函,其耦合系数反映了不同特征量泛函之间的耦合强度.依据定量因果原理,导出了一般n阶特征量泛函的变分原理,获得了一般n阶特征量泛函的Euler-Lagrange方程,它的不同系数可拟合不同的物理现实,如从线性到任意n阶非线性物理系统,使复杂难解的任意n阶非线性物理系统变得具体可解.并获得了该对称变换下不变的m个的守恒量,以及它们之间的关系和统一描述.依据定量因果原理导出了相对性原理,证明了绝对加速参考系、牵连参考系和相对参考系的力都有来自加速度和质量变化的贡献.利用定量因果原理自然导出了广义牛顿第一定律和广义牛顿第二定律,而且还导出了一个新定律,即广义牛顿第三定律,亦即平移不变性系统合力为零定理.进而将研究结论应用于对银河系的修正引力势、分子势、夸克禁闭势等,且其结果与物理实验一致.