Energies of interband optical transition in InGaAs/InAlAs multi-quantum well (MQW) structures were studied using one undoped and two n-type modulation-doped specimens grown by MBE. Step-like allowed transitions were o...
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Energies of interband optical transition in InGaAs/InAlAs multi-quantum well (MQW) structures were studied using one undoped and two n-type modulation-doped specimens grown by MBE. Step-like allowed transitions were observed and identified between 120 K and 330 K. In a 10 nm-thick quantum well (QW), three typical eigen states of the conduction subband (CS) were discriminated in a 0.52 eV range of energy in the QW. Doped and undoped MQW specimens had almost the same transition energies from the valence subband to the CSs. In a highly doped specimen of 1.5/spl times/10/sup 12/ cm/sup -2/ electrons per QW, the inter-ground-state optical transition was prohibited by the band filling effect. In the low doped specimen of 5/spl times/10/sup 11/ cm/sup -2/ electrons per QW, however, the same transition below the Fermi energy level was observed at 120 K. Moreover, localized states or an impurity band with an activation energy of 25 meV associated with the ground and the second higher CSs, were observed. No localized state was observed in the undoped ones.
The dispersion relation and the optical transmittance of a two-dimensional photonic crystal composed of the hexagonal array of cylindrical air holes fabricated in a dielectric slab were analyzed by group theory and th...
The dispersion relation and the optical transmittance of a two-dimensional photonic crystal composed of the hexagonal array of cylindrical air holes fabricated in a dielectric slab were analyzed by group theory and the numerical calculation based on the finite-difference time-domain method. The decay rate of the leaky modes that exist above the light line (the dispersion relation in air) in the band diagram was also evaluated, from which the absence of the coupling between certain internal eigenmodes and the external radiation field was shown. This phenomenon was related to symmetry mismatching by the group-theoretical argument. It was also shown that a certain leaky band has a quality factor as large as 3000 over its entire spectral range. These features as well as the opaque frequency regions due to symmetry mismatching were clearly demonstrated by the calculated optical transmission spectra.
Jackal is a Java-based tool for communication using the KQML agent communication language. Some features that make it extremely valuable to agent development are its conversation management facilities, flexible, black...
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ISBN:
(纸本)0769503403
Jackal is a Java-based tool for communication using the KQML agent communication language. Some features that make it extremely valuable to agent development are its conversation management facilities, flexible, blackboard style interface and ease of integration. Jackal has been developed in support of an investigation of the use of agents in enterprise-wide integration of planning and execution for manufacturing. This paper describes Jackal at a surface and design level, and demonstrates its use in a multiagent system that supports intelligent integration of enterprise planning and execution.
Some of the features that make Jackal (Java-based Applications Communication using KQML Agent communication Language) extremely valuable to agent development are its conversation management facilities, its flexible, b...
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Some of the features that make Jackal (Java-based Applications Communication using KQML Agent communication Language) extremely valuable to agent development are its conversation management facilities, its flexible, blackboard-style interface and its ease of integration. Jackal has been developed in support of an investigation of the use of agents in enterprise-wide integration of planning and execution for manufacturing. This paper describes Jackal at a surface level and at the design level, and demonstrates its use in a multi-agent system that supports intelligent integration of enterprise planning and execution.
The photoconvertible surface wettability of TiO 2 materials —UV illumination of these materials can generate surfaces that display a 0° contact angle for both water and oily liquids—is investigated. Frictional ...
The photoconvertible surface wettability of TiO 2 materials —UV illumination of these materials can generate surfaces that display a 0° contact angle for both water and oily liquids—is investigated. Frictional force, X‐ray photoelectron, and Fourier transform infrared spectroscopies are used to supply information at a microscopic level. It is concluded that UV illumination is able to convert initially hydrophobic TiO 2 surfaces into highly amphiphilic ones. This behavior is ascribed to photogenerated Ti 3+ defect sites that favor dissociative water adsorption.
This chapter describes CO 2 electrochemical reduction on high area metal electro catalysts supported on activated carbon fibers (ACF), which contain slit-shaped pores with width on the order of nanometers. Such electr...
This chapter describes CO 2 electrochemical reduction on high area metal electro catalysts supported on activated carbon fibers (ACF), which contain slit-shaped pores with width on the order of nanometers. Such electro catalysts were used in the form of gas diffusion electrodes (GDE), which are used in the fuel-cell field. The structure of this type of electrode is shown in the chapter. The reaction takes places at the gas phase / electrolyte (liquid phase) / electrode interface, the so-called three-phase boundary.
In an era of fiscal austerity, downsizing and unforgiving pressure upon human and economic capital, it is an Augean task to identify resources for fresh and creative work. The realities of the day and the practical de...
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In an era of fiscal austerity, downsizing and unforgiving pressure upon human and economic capital, it is an Augean task to identify resources for fresh and creative work. The realities of the day and the practical demands of more immediate fleet needs can often dictate higher priorities. Yet, the Navy must avoid eating its seed corn. Exercising both technical insight and management foresight, the fleet, the R&D community, the Office of the Chief of Naval Operations (OpNav) and the product engineering expertise of the Naval Surface Warfare Center (NSWC) are joined and underway with integrated efforts to marry new, fully demonstrated technologies and operational urgencies. Defense funding today cannot sponsor all work that can be mission-justified over the long term because budgets are insufficient to support product maturation within the classical development cycle. However, by rigorous technical filtering and astute engineering of both marketplace capabilities and currently available components, it is possible in a few select cases to compress and, in effect, integrate advanceddevelopment (6.3), engineering development (6.4), weapon procurement (WPN), ship construction (SCN), operation and maintenance (O&M,N) budgetary categories when fleet criticalities and technology opportunities can happily meet. In short, 6.3 funds can be applied directly to ''ripe gateways'' so modern technology is inserted into existing troubled or aging systems, sidestepping the lengthy, traditional development cycle and accelerating practical payoffs to recurrent fleet problems. To produce such constructive results has required a remarkable convergence of sponsor prescience and engineering workforce excellence. The paper describes, extensively, the philosophy of approach, transition strategy, polling of fleet needs, technology assessment, and management team requirements. The process for culling and selecting specific candidate tasks for SHARP sponsorship (matching operational need with t
作者:
Schulte, DPSkolnick, AHe has supported the development and operation of several naval systems
including advanced component selection for Trident II fire control and navigation systems. He served as branch manager of the Surface Ship ASW Combat System Branch which acted as the acquisition engineering agent for the AN/SQQ-89 Surface Ship Anti-Submarine Warfare Weapon System. He was then selected to manage the Module Engineering Department which provided engineering support to numerous naval systems including the AN/BSY-1 Submarine Combat System and the Trident II fire control and navigation system. He then served as the deputy program manager for NAVSEA Progressive Maintenance (2M/ATE). He holds a B.S. degree in Electrical Engineering from Purdue University and currently is pursuing a Maste's degree in Public Environmental Affairs at Indiana University—Purdue University
Indianapolis. He served at Applied Physics Laboratory/The Johns Hopkins University in missile development
then aboard USS Boston (CAG-1) and played leading roles in several weapon system developments (Regulus Terrier Tartar Talos) inertial navigation (Polaris) deep submergence (DSRV) and advanced ship designs (SES). He later was director Combat System Integration Naval Sea Systems Command and head Combat Projects Naval Ship Engineering Center. He led the Navy's High Energy Lasers and Directed Energy Weapons development efforts. He was vice president advanced technology at Operations Research Inc. and vice president maritime engineering at Defense Group Inc. before starting SSC in 1991. Dr. Skolnick holds a B.S. degree in Mathematics and Economics
Queens College an M.A. degree in Mathematics and Philosophy Columbia University an M.S. degree in Electrical/Aeronautical Engineering U.S. Naval Postgraduate School and a Ph.D. in Electrical Engineering and Applied Mathematics from Polytechnic University in New York. He is the author of many published papers on engineering design issues source selection procedures and large-scale complex technology problems
The Fleet continues to require high performance systems that can operate with dependability in the seas' unforgiving environments and under hostile action. Those demands are not new. What has changed is the urgent...
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The Fleet continues to require high performance systems that can operate with dependability in the seas' unforgiving environments and under hostile action. Those demands are not new. What has changed is the urgent priority formerly assigned to national defense issues. The arguments for continued superpower military strength are now roiled in politics along with unsettled budgets and uncertain force level projections. Current expectations revolve about indefinite fiscal and operational issues (difficult funding constraints and broadband threats). In the actual event of ''doing more with less,'' a practical response is to apply the creative power available from sound engineering judgement and the crucible of experience to the immediate needs of the Fleet. The attempt to shorten the path between advanceddevelopment effort and Fleet use has been tried occasionally in the past, often, without exemplary results. The Sustainable Hardware and Affordable Readiness Practices (SHARP) program, is a generic R&D effort under OpNav sponsorship that has been working steadily on sensible solutions to product engineering problems. Armed today with fast-time, large-scale computation abilities and modern tools for technical problem solving coupled with specialized engineering knowledge, it has been refreshed and is underway satisfying existing Fleet needs. The relationship between fully responsive engineering services and current operational needs is always demanding. The connection between advanced engineering development (6.3 category funds) and immediate Fleet usage brings added complexity and challenge, both technical and organizational. Illustrative examples of affordable engineering solutions to ''retain, revise, replace or retire'' questions are presented within the context of both Fleet realities and budgetary limitations. The discussion covers legacy system support, civil/military considerations and Fleet maintenance issues. It describes the substantial and critical payoffs i
Providing realistic opposing forces is critical to the successful use of military training simulations. Unfortunately, a number of issues can make the manual control of realistic opposing forces difficult or unattaina...
Providing realistic opposing forces is critical to the successful use of military training simulations. Unfortunately, a number of issues can make the manual control of realistic opposing forces difficult or unattainable, This paper explores these issues while discussing how Automatic Interactive Targets (AITs) can assist Training Exercise Controllers (TECs) in providing validated and realistic opposing forces in highly interactive situations. The features of the prototype Remote AIT Processing System (RAPS) are used to demonstrate how an AIT system can be designed to meet TEC requirements for automated entities, RAPS can provide remote control of AITs for existing or new systems while providing sufficient features to allow a TEC to appropriately select and control AITs for individual training exercises and crew proficiencies.
The military services are being moved in the direction of performance-based specifications and standards. They are being steered against dictating ''how to'' produce an item since such action foreclose...
The military services are being moved in the direction of performance-based specifications and standards. They are being steered against dictating ''how to'' produce an item since such action forecloses on the ability to gain access to components or technology that may have a commercial equivalent. Why should the engineering community embrace the new approach? Aside from the obvious weight of it being approved policy, therefore currently mandated, it warrants examination because it is the correct approach at this time when applied to appropriate products. Military specifications and standards are to be displaced then, by acceptable alternative contractor design solutions. Industry bidders will be allowed to propose the particular design details, permitting procurement flexibility by contractually citing only system level or interface requirements, both physical and functional. Hopefully, this can broaden the industrial base and increase competition with reduced costs to follow. Conceptually, the approach appears both performance-sensible and cost-attractive (there are, of course, consequent risks) but how does implementation proceed? Is it possible to pursue the goals envisioned along paths that are not in themselves experimental? Can the American postulate, minimal loss of life and limb to U.S. military people, continue to be honored? Experience and track record elsewhere imply encouraging possibilities in select situations-useful prospects are identified and discussed in practical terms.
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