长波红外和中波红外超光谱傅里叶变换成像器

Kestrel公司已设计出一种装在飞机上的双波段红外傅里叶变换超光谱成像器,目前正在制造这台仪器。预定安装在Cessna206上的这台成像器具有一个15度的视场,其瞬时视场为1.0毫弧度。该仪器使用512个光谱通道,在2000cm^-1至3000cm^-1范围内,其目标光分辨率优于1.5cm^-1,在850cm^-1至1250cm^-1范围内则优于0.4cm^-1。为达到这些前所未有的光谱分辨率,仪器将采用各种光谱增强技术。光学系统的计算机模拟已演示出亚波数分辨率和超过900的信噪比。     

Reactive transport in porous media: a comparison of model prediction with laboratory visualization

Groundwater transport models that accurately describe spreading of nonreactive solutes in an aquifer can poorly predict concentrations of reactive solutes. The dispersive term in the advection-dispersion equation can overpredict pore-scale mixing, and thereby overpredict homogeneous chemical reaction. We quantified this experimentally by imaging instantaneous colorimetric reactions between solutions of aqueous CuSO4 and EDTA4- within a 30-cm long translucent chamber packed with cryolite sand that closely matched the optical index of refraction of water. A charge-coupled device camera was used to quantify concentrations of blue CuEDTA2- within the chamber as it was produced by mixing of the two reactants at different flow rates. We compared these experimental results with a new analytic solution for instantaneous bimolecular reaction coupled with advection and dispersion of the product and reactants. For all flow rates, the concentrations of CuEDTA2- recorded in the experiments were about 20% less than predicted by the analytic solution, thereby demonstrating that models assuming complete mixing at the pore scale can overpredict reaction during transport.     

Development of an expert system for diagnosing component-levelfailures in a shuttle car

The development of a rule-based expert system (referred to as SCAR) for assisting electricians in diagnosing electrical faults in a shuttle car is discussed. Insight 2+, a microcomputer-based expert-system development tool by Level Five Research, Inc. was used in creating the system. The program requires the user to specify the initial symptoms of the failed machine; then the most probable cause of failure is traced through the knowledge base, with the software requesting additional information, such as voltage or resistance measurements, as needed. A causal-reasoning approach, which was used to develop the production rules, is described. The organization, implementation, and limitations of the knowledge base are also presented, along with a brief discussion of the ongoing development of a new system, SCAR.2     

Experimental visualization of solute transport and mass transfer processes in two-dimensional conductivity fields with connected regions of high conductivity

Solute transport displaying mass transfer behavior (i.e., tailing) occurs in many aquifers and soils. Spatial patterns of hydraulic conductivity may play a role because of both advection and diffusion through isolated low conductivity areas. We demonstrated such processes in laboratory experiments designed to visualize solute transport through a thin chamber (40 cm x 20 cm x 0.64 cm thick) packed with glass beads and containing circular emplacements of smaller glass beads with lower conductivity. The experiments used three different contrasts of conductivity between the large-bead matrix and the emplacements, targeting three different regimes of solute transport: low contrast, targeting macrodispersion; intermediate contrast, targeting advection-dominated mass transfer between the high-conductivity regions and the emplacements; and high contrast, targeting diffusion-dominated mass transfer. Use of a strong light source, a high-resolution CCD camera, and a colorimetric dye produced images with a spatial resolution of about 400 microm and a concentration range of approximately 2 orders of magnitude. These images confirm the existence of the three different regimes, and we observed tailing driven by both advection and diffusion. Outflow concentration measured by spectrophotometer achieved 3 orders of magnitude in concentration range and showed good agreement with known models in the case of dispersion and diffusive mass transfer, with estimated parameters close to a priori predictions. Existing models for diffusive mass transfer did notfitthe breakthrough curves from the intermediate-contrast chamber, but a model of slow advection through cylinders did. Thus, both breakthrough curves and chamber images confirm that different contrasts in small-scale K lead to different regimes of solute transport and thus require different models of upscaled solute transport.     

Enhancement of JET’s mirror-link near-ultraviolet to near-infrared divertor spectroscopy system

Since 1994, JET has had a mirror-link spectroscopy system with a poloidal view of 150 mm of the outer divertor split into three ranges: near-ultraviolet (near-UV) (～ 300–450?nm), visible (450–750 nm), and near-infrared (near-IR) (750–1200 nm). The system consists of three Czerny–Turner/charge coupled device (CCD) pairs: 1 m focal length for the near-UV, 0.75 m focal length for the visible, and 0.5 m focal length for the near-IR. All were aligned along the same optical path to the divertor. As part of the JET ITER-like wall enhancements, the diagnostic system will be upgraded in five areas: (1) frame rate, (2) quantum efficiency (QE), (3) radial coverage, (4) optical throughput, and (5) for the near-UV, spectral resolution and survey capability. New CCDs for the near-UV and visible will have increased QE and allow three times frame rate. The near-UV will benefit from a 0.75 m imaging spectrometer with three gratings. The optics have been redesigned to allow ～ 360?mm view and greater than two times throughput. This paper will look at the design and implementation as well as the new diagnostic capabilities of the system.     

Spatial fidelity of photorefractive image correlators

The set of equations describing photorefractive four-wave mixing of image-bearing beams has been solved in the presence of diffraction using a perturbation analysis assuming a strong uniform backward pump and a weak conjugate. To first order, it was found that the conjugate image is bilinearly related to the forward-pump and probe images. By using a Green's function approach, an analytical expression for the bilinear kernel was derived. This kernel, which governs the bandwidth of the conjugation system, is a function of the material parameters, the beam angles, and the crystal length. When a conjugator is used to determine the correlation between two images, the result was found to be a distorted version of the correlation image. This distortion was reduced when the image with the smallest extent was chosen as the forward-pump image     

Potentials for productivity enhancement from psychological research and development.

Reviews the nature of a pressing national problem—decline in US productivity growth—and discusses the vague concept of productivity as described in the current literature. The authors observed that traditional psycholgical approaches to productivity enhancement have tended to concentrate on employee or organizational productivity at the micro-economic level. It is argued that psychological research and development has much greater improvement potential at the macro-economic (i.e., national) productivity level. An example is given of possible contributions of psychological research and development with regard to improving the accuracy and utility of economic forecasts. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)