current investigations of material issues in mass-transport fabrication are reviewed. Evaporation loss and resulting surface roughness have been identified and simple techniques developed for effective prevention. Pho...
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The thermal infrared (TIR) radiometer is one of three radiometers installed on the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), slated to be launched aboard Eos-A of NASA's polar orbitin...
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ISBN:
(纸本)081940599X
The thermal infrared (TIR) radiometer is one of three radiometers installed on the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), slated to be launched aboard Eos-A of NASA's polar orbiting platform in 1998. The TIR, a multichannel scanning radiometer for the thermal infrared region, is used for observation in various fields, including geology, mineral resources, meteorology, and oceanography. Trial manufacture and testing for the BBM is currently underway. This paper gives an overview of the TIR currentdesign.
The Reflection Grating Spectrometer Experiment (RGS), which has been selected for flight on the European Space Agency's X-Ray Multi-Mirror Mission (XMM), includes two arrays of reflection gratings that are placed ...
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The Reflection Grating Spectrometer Experiment (RGS), which has been selected for flight on the European Space Agency's X-Ray Multi-Mirror Mission (XMM), includes two arrays of reflection gratings that are placed in the X-ray optical path behind two separate grazing incidence X-ray telescopes. Each of the grating arrays picks off roughly half the X-ray light emanating from its telescope and diffracts it to a dedicated strip of charge-coupled device (CCD) detection offset from the telescope focal plane. The arrays contain 224 100 mm × 200 mm gratings, each mounted at a graze angle of 1.58° to the incident beam. The gratings are produced by epoxy replication of a common master onto very thin substrates. Both the gratings and the detectors are mounted on a Rowland circle which also includes the telescope focus. In this paper, we review the current state of both the engineering and the opticaldesigns for the grating arrays.
Biological sensor design has long provided inspiration for sensor design in machine vision. However, relatively little attention has been paid to the actual design parameters provided by biological systems, as opposed...
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Biological sensor design has long provided inspiration for sensor design in machine vision. However, relatively little attention has been paid to the actual design parameters provided by biological systems, as opposed to the general nature of biological vision architectures. In the present paper, we provide a review of current knowledge of primate spatial vision design parameters and present recent experimental and modeling work from our lab which demonstrates that a numerical conformal mapping, which is a refinement of our previous complex logarithmic model, provides the best current summary of this feature of the primate visual system.
A short review of recent developments in laser photocathode is presented. The importance of different processes, such as the single and multiphoton photoelectric effects are analyzed on the basis of recent experimenta...
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ISBN:
(纸本)0819406805
A short review of recent developments in laser photocathode is presented. The importance of different processes, such as the single and multiphoton photoelectric effects are analyzed on the basis of recent experimental results. The conditions for the formation of small divergence, short pulse duration, and high current density electron beam from metallic photocathodes are discussed. Other types of photocathodes can be used as the semiconductor (GaAs, chalcopyrite) in order to produce polarized electrons. The main steps and the diagnostics for applications in photoinjector development is discussed.
This paper is concerned with the overall architecture and the performances of the Pointing, Acquisition and Tracking (PAT) subsystem of the European SILEX program (Semiconductor laser Intersatellite Link Experiment). ...
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This paper is concerned with the overall architecture and the performances of the Pointing, Acquisition and Tracking (PAT) subsystem of the European SILEX program (Semiconductor laser Intersatellite Link Experiment). Starting from the description of the mission constraints, it deals with the retained baseline built around a two-stages beam steering system, an open loop point-ahead control and a full digital implementation. Performance prediction is based upon signal processing, control algorithms and detailed modelling of equipments and flexible structures. It shows how such an accurate performance in the order of a microradian can be achieved with a correct allocation of the performance for each equipment of the system. In particular the rejection of the microvibrations coming from the platform when the Terminal is operating will be pointed out as a key-feature of the design. The PAT equipments and softwares - sensors, electromechanisms, control units - are presented showing which technological step is achieved (from current advanced C/D phase programs) or still to be achieved.
As business environments become more and more information-intensive, an organization's approach to collecting, processing and disseminating information becomes a significant determinant of its productivity, delive...
As business environments become more and more information-intensive, an organization's approach to collecting, processing and disseminating information becomes a significant determinant of its productivity, delivery performance, quality, profitability, and overall competitiveness. Integrated Manufacturing Systems (IMS) of the 1990s and beyond will require a totally integrative management of the manufacturing enterprise. This focus on the integration of the entire enterprise rather than a narrow focus in just the manufacturing function places more stringent demands on data integrity in order to effectively coordinate the activities required to carry out the functions aimed at attaining the organizational mission. An overview is presented on the current body of knowledge on Automated Data Capture (ADC) technologies, including: bar coding, radio frequency identification, radio frequency communication, optical character recognition, voice recognition systems, machine vision, magnetic stripes, Electronic Data Interchange (EDI), and systems design and integration considerations. These technologies, collectively referred to as keyless data entry techniques, automated data capture, techniques, or Automatic Identification (Auto ID)technologies are critical to the success of automated manufacturing systems, distribution, inventory control and other computer facilitated activities related to enterprise integration.
A coaxial accelerator which will launch a 45 mm diameter, 225 g-mass to 2,000 m/s is described. The launcher is a true induction device, as no current feed to the armature is provided. The armature is a multiturn desi...
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A coaxial accelerator which will launch a 45 mm diameter, 225 g-mass to 2,000 m/s is described. The launcher is a true induction device, as no current feed to the armature is provided. The armature is a multiturn design, which forces a uniform current density and prevents excessive heating at the rear of the armature. To meet the 450 kJ launch goal, the accelerator is composed of 47 separate stages. Each stage has its own capacitor power supply, which is discharged upon arrival of the armature. The system uses a "sense and switch" approach to ensure correct timing of the power supply discharges. In-bore armature position is detected using fiber optics;the necessary signals are fed into a programmable controller, which determines the velocity. Using this calculation, the controller determines the ideal time to fire the next stage and initiates the discharge at the appointed time. The accelerator described here is roughly 38% efficient (kinetic energy/stored energy) with a bore diameter of 45 mm. Simulations indicate efficiencies over 55% are possible with a 60 mm bore launcher and continue to increase with larger bore sizes. This paper discusses the launcher and armature designs, power supply, and controls. Predicted performance of a five-stage launcher currently being built is presented. Experimental results from single-stage tests are presented and compared to simulated results. Solid (monolithic) and multiturn (wound) armature tests are also described.
In this paper, we describe the design of a fully reversible IR fibre optic chemical sensor for glucose based on the chemical modification of the fibre surface. The chalcogenide glass fibre (composed of As, Se, and Te)...
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An increasing practical problem in the evaluation of the accuracy of new imaging systems, as well as the effect of modifications in the display of current imaging systems, is the effort entailed in performing the nece...
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ISBN:
(纸本)0819405418
An increasing practical problem in the evaluation of the accuracy of new imaging systems, as well as the effect of modifications in the display of current imaging systems, is the effort entailed in performing the necessary readings. Although some constraints are dictated by the specific evaluation being conducted, some aspects of the experiment can be determined by the investigator. These include, but are not limited to, the method used to select the cases (selected, stratified, or random) and whether continuous variables that are being evaluated (i.e., pixel size, brightness, contrast) are grouped into discrete categories. The selection of the experimental design has an impact on the sample size required to answer the study question and thus impacts on the cost and effort required to do the study.
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