Tunable CW laser oscillation of NdP5O14 at 1.3 μm

Low-threshold tunable cw laser oscillation is achieved at the⁴ F _3/2⁴ I _13/2 transition of NdP₅O₁₄. Continuous tunign over 1.8% of the central wavelenght is possible with 55 mW of absorbed pump power. At gain line maximum near 1.32 , the output power exceeded 1 mW. Pump threshold as low as 8 mW was observed. Reliable cw operation of the 1.3 m NdP₅O₁₄ laser pumped by a 15 mW AlGaAs laser diode is demonstrated.     

Low Pass metallic mesh interference filters for operation in the 165 GHz to 880 GHz region

Low Pass metallic mesh interference filters have been designed and constructed for operation in the region 340 m (880 GHz) to 1.8 mm (165 GHz). These filters have been shown to have excellent edge characteristics and good rejection regions. The results show that the mesh filter can be effectively used in both millimetre and submillimetre regions.Part of this work was performed while this author was at Heriot-Watt University, Edinburgh, U.K.     

荧光光谱法研究酸性大红3R与牛血清白蛋白的结合作用

在Tris缓冲溶液(pH 7.4)体系中,运用荧光光谱法和紫外光谱法首次研究了染料酸性大红3R(AS)与牛血清白蛋白(BSA)的相互作用,并考察了表面活性剂对体系荧光强度的影响。结果表明,酸性大红3R与牛血清白蛋白能形成基态复合物,从而导致BSA内源荧光猝灭,猝灭机理主要涉及静态猝灭和非     

SO q (n+1,n−1) as a real form of SO q (2n,ℂ)

Quantum pseudo-orthogonal groups SO _q (n+1,n–1) are defined as real forms of quantum orthogonal groups SO _q (n+1,n–1) by means of a suitable antilinear involution. In particular, the casen=2 gives a quantized Lorentz group.     

Classical physics and Penrose's thesis

We expose and discussPenrose's thesis: Nature produces harnessable noncomputable processes, but none at the classical level. We then suggest a partial counterexample to it, based on aGedanken experiment about an undecidable family of integrable Hamiltonian systems that could lead to a sort of idealized solution to the Halting problem for Turing machines.1. Partially supported by a Fulbright/CNP_q-Brazil grant. Permanent address after November 5, 1990: Center for the Study of Mathematical Theories of Communication, IDEA/School of Communications, Federal University of Rio de Janeiro, Av. Pasteur 250, 22290 Rio de Janeiro, RJ Brazil.     

Algebraic models defined over Q of differential manifolds

Here we prove that every compact differential manifold has a smooth algebraic model defined over Q. In dimension 2 we find an algebraic model (may be singular) defined over Q and birational over Q to the projective plane.     

Spline collocation for strongly elliptic equations on the torus

Summary We prove convergence and error estimates in Sobolev spaces for the collocation method with tensor product splines for strongly elliptic pseudodifferential equations on the torus. Examples of applications include elliptic partial differential equations with periodic boundary conditions but also the classical boundary integral operators of potential theory on torus-shaped domains in three or more dimensions. For odd-degree splines, we prove convergence of nodal collocation for any strongly elliptic operator. For even-degree splines and midpoint collocation, we find an additional condition for the convergence which is satisfied for the classical boundary integral operators. Our analysis is a generalization to higher dimensions of the corresponding analysis of Arnold and Wendland [4].     

全变差有界函数列的一致(R)可积性

给出了一致有界单调函数列一致可积性定理 ,由此得出全变差序列有界的收敛函数列的一致可积性 .说明了该结论可判断一些非一致收敛函数列的逐项积分性质 .     

Nonlinear Liouville theorems for Grushin and Tricomi operators

The aim of this paper is to study necessary conditions for existence of weak solutions of the inequality