Recoil-free spectroscopy of neutral Sr atoms in the Lamb-Dicke regime

Recoil-free as well as Doppler-free spectroscopy was demonstrated on the 1S0-3P1 transition of Sr atoms confined in a one-dimensional optical lattice. By investigating the wavelength and polarization dependence of the ac Stark shift acting on the 1S0 and 3P1(m(J)=0) states, we determined the wavelength where the Stark shifts for both states coincide. This Stark-free optical lattice, allowing the purturbation-free spectroscopy of trapped atoms, may keep neutral-atom based optical standards competitive with single-ion standards.     

Magnetic-field induced transition to the 1/2 magnetization plateau state in the geometrically frustrated magnet CdCr2O4

The magnetization of the geometrically frustrated spinel CdCr2O4 was measured in pulsed fields of up to 47 T. We found a metamagnetic transition to a very wide magnetization plateau state with one half of the full moment of S=3/2 Cr3+ at 28 T, independent of the field direction. This is the first observation of magnetization plateau state realized in Heisenberg pyrochlore magnet. The plateau state can be ascribed to a collinear spin configuration with three-up and one-down spins out of four spins of each Cr tetrahedron. A large magnetostriction is observed at the transition in spite of the negligible spin-orbit couplings. We argue that spin frustration plays a vital role in this large spin-lattice coupling.     

Analyzing powers for the (p, α) reactions on 58, 60, 62Ni at Ep = 22 MeV

Measurements of both the analyzing power and cross section were made for the (p, α) reactions on ^58,60,62Ni at an incident energy of 22 MeV. Data were taken for the strongly populated proton-hole states (0f_{$\text{7}\text{2}$}, 1s_{$\text{1}\text{2}$} and 0d_{$\text{3}\text{2}$}) in the residual cobalt isotopes and for 8 weakly populated low-lying states in ⁵⁵Co and ⁵⁹Co. Angular distributions were taken between θ_lab = 10° and 140° for the ground state and θ_lab = 10° and 80° for the excited states. Both the cross sections and analyzing powers exhibit a similar angular distribution for states having the same J^π values except in the transition to the $\text{3}\text{2}$^? state in ⁵⁹Co at 1.099 MeV. Using the observed J-dependence of the analyzing power, the unknown J^π values for the states at 2.982 MeV in ⁵⁵Co and 3.090 MeV in ⁵⁹Co are assigned to be $\text{9}\text{2}$^?. The shapes of the differential cross sections were well reproduced by the zero-range DWBA calculations using a triton-cluster form factor. However, all the measured analyzing powers could not be reproduced within the framework of such a simple DWBA calculation.     

Dualities for the Domany–Kinzel Model

We study the Domany–Kinzel model, which is a class of discrete-time Markov processes in one-dimension with two parameters (p ₁,p ₂)[0,1]². When p ₁= and p ₂=(2– ²) with (,)[0,1]², the process can be identified with the mixed site-bond oriented percolation model on a square lattice with probabilities of a site being open and of a bond being open. This paper treats dualities for the Domany–Kinzel model _t ^A and the DKdual _t ^A starting from A. We prove that , as long as one of A,B is finite and p ₂p ₁.     

木质素磺酸盐表面活性剂的研究和应用进展

论述了木质素磺酸盐结构方面的研究、木质素磺酸盐的分离纯化和化学改性制备表面活性剂的方法、木质素磺酸盐表面活性剂应用取得的进展和研究面临的挑战。最后总结认为:进一步加强木质素磺酸盐结构和性能的基础研究,结合界面化学的最新理论成果和现代分析测试手段,通过改性解决木质素磺酸盐的颜色和活性问题,开发可用于日用领域的新型环保的木质素磺酸盐表面活性剂,是木质素磺酸盐这一绿色资源得到高值化利用的一个重要方向,同时木质素磺酸盐在导电高分子等先进材料制备领域具有重大的研究潜力。     

Strong evidence of alpha-particle doorway states in 28Si observed in alpha-decays to low-lying states of 24Mg

Four ratios of alpha-particle decay probabilities to specific members of the K-bands of ²⁴Mg were measured at bombarding energies E_cm = 19.7 to 28.2 MeV. The energies for enhancement of these ratios correspond quite well to the 0⁺ resonances reported.     

基于红外指纹图谱的螺旋藻品质分析和蛋白含量测定

采用傅里叶变换红外光谱(FTIR)分析技术,对螺旋藻标准品、螺旋藻粉样品和糊精标准品的红外光谱进行分析。螺旋藻中的蛋白质(1 657,1 537 cm-1)和糖类(1 069,1 054 cm-1)具有明显的红外指纹特征。螺旋藻粉中的主要成分为蛋白质和糖类,主要辅料为糊精。比较28个不同厂家螺旋藻粉的红外指纹图谱,计算图谱相关系数确定出辅料添加比例的高低。建立吸收峰强度比和蛋白质含量的关联标准曲线,形成依据红外光谱测定样品蛋白含量的方法,与凯氏定氮法测定结果相对偏差小于5%,为螺旋藻粉品质鉴定提供了一种简便、快速、无损的新方法。     

液晶环氧树脂/蒙脱土纳米复合材料的制备和固化反应动力学研究

用带有介晶基元的联苯二酚二缩水甘油醚 (BP)、4 氨基苯基磺酰胺 (SAA)和有机化蒙脱土 (93A)采用浇铸成模固化成型的方法制备出液晶环氧树脂 蒙脱土纳米复合材料 .WRXD结果表明 93A含量是 2 %时可形成剥离型纳米材料 ,而当 10 %时形成插层型纳米材料 ,5 %时则形成剥离和插层混合型的纳米材料 ;POM结果表明蒙脱土的存在能够破坏原有的扇形近晶相液晶织构 .DSC研究表明体系的固化反应动力学 ,可用变形的Kissinger Akahira Sunose法 (VKAS)表征 ,从求出的反应活化能和转化率关系 ,发现反应初期 ,蒙脱土使反应活化能降低 ,能够促进液晶环氧树脂的固化 .     

Non-Equilibrium Dynamics of Dyson’s Model with an Infinite Number of Particles

Dyson’s model is a one-dimensional system of Brownian motions with long-range repulsive forces acting between any pair of particles with strength proportional to the inverse of distances with proportionality constant β/2. We give sufficient conditions for initial configurations so that Dyson’s model with β = 2 and an infinite number of particles is well defined in the sense that any multitime correlation function is given by a determinant with a continuous kernel. The class of infinite-dimensional configurations satisfying our conditions is large enough to study non-equilibrium dynamics. For example, we obtain the relaxation process starting from a configuration, in which every point of \mathbbZ{\mathbb{Z}} is occupied by one particle, to the stationary state, which is the determinantal point process with the sine kernel.