实验室的认可和质量管理体系的建立与运行

简要介绍了实验室认可的发展情况，开展实验室认可的必要性，实验室的质量管理体系的建立、运行及认证认可。     

Mean stability of stochastic difference systems

In this paper the mean stability of linear and non-linear stochastic difference systems is considered. For linear systems the relationship between mean stability and other stability definitions is explored. For the non-linear system explicit criteria for mean stability are derived when the non-linear term satisfies a certain realistic condition.     

Light scattering by fluffy particles with the PROGRA experiment: Mixtures of materials

The PROGRA² experiment is specifically designed to measure the linear polarization of the light scattered by clouds of particles. The imaging method allows us to obtain maps of polarization and to measure the size distribution and the number density of the particles in the field of view. This work presents a systematic study of highly porous (fluffy) aggregates with submicron-sized constituent grains lifted by an air-draught. The main materials are silica and carbon. The maximum in polarization mainly depends on the average size of the constituent grains. The results, mainly concerned with the negative branch of the phase curves, the maximum polarization, the color effect and the albedo are compared with cometary observations and discussed in terms of physical properties.     

Early Attempts to Detect the Neutrino at the Cavendish Laboratory

In the 1920s and early 1930s the Cavendish Laboratory in Cambridge was preeminent in experimental research on radioactivity and nuclear physics, with theoretical physics playing a subsidiary role in guiding, but not determining the course of experimental research. Soon after Wolfgang Pauli (1900–1958) proposed his neutrino hypothesis in 1930 to preserve conservation of energy and momentum in beta decay, experiments – the first of their kind – were carried out in the Cavendish Laboratory to detect Pauli’s elusive particle, but they were abandoned in 1936. I trace these early attempts and suggest reasons for their abandonment, which may contribute to an understanding of the complex way in which theoretical entities are accepted by physicists.     

Laboratory astrophysics and non-ideal equations of state: the next challenges for astrophysical MHD simulations

Laboratory astrophysics holds great promise not only as a highly effective validation tool for astrophysical magneto-hydrodynamics (MHD) codes but it also presents a unique challenge for these codes. The high-density plasmas found in these experiments are not well modeled by the ideal equations of state (EOS) found in most astrophysical simulation codes. To solve this problem, we replaced the ideal EOS scheme in an existing MHD code, AstroBEAR, with a non-ideal EOS method and validated our implementation with van der Waals shock tube tests. The improved code is also able to model flows that contain more than one material, as required in laboratory experiments. Simulations of jet experiments performed at the OMEGA Laser reproduce the morphology of the jet much better than when the code used a single material and an ideal EOS.     

Polygon diagrams of chromatographic data

Use of a Hewlett-Packard 2648 A graphics terminal connected to a HP 3354 B Laboratory Automation System for drawing polygon diagrams of chromatographic data has been investigated. The computer program is designed to reduce polygon overlapping and hiding by fully automatic parameter adjustment.     

Wavelength-dependent enhancement of DCP metal lines by saline matrices

Sodium-induced emission enhancement of transition metal resonance lines are measured in a d.c. plasma (DCP) for wavelengths from 210 to 395 nm. Systematic differences in enhancement are observed within individual spectra (Fe I, Ni I, Sc II), and the enhancement and the excitation potential of a line are found to be linearly related. Electron density and apparent temperature data lead to an interpretation of thiis energy dependence within the context of a recombining plasma in partial thermodynamic equilibrium.     

A study of the dalitz plot in the decay KL0 → π+π−π0

The results are presented of an analysis of 4709 fully reconstructed K_L⁰ → π⁺π^?π⁰, observed in a hydrogen bubble chamber. The data fit to a linear π⁰ energy spectrum to give a slope parameter g = 0.610 ± 0.022.     

Subgroup alignment in hypercolor theories

To analyze the physical consequences of a dynamically broken theory of the weak interactions, we must know how the weak gauge group is aligned in an approximate flavor-symmetry group. For a large class of models, spectral-function sum rules enables us to determine this alignment explicitly. We work out the pattern of the electroweak symmetry breakdown for several sample models. Critical values of weak mixing angles are found at which the breakdown pattern changes discontinously. We compute pseudo-Goldstone boson masses, and find that some models contain unusually light charged or colored pseudo-Goldstone bosons.