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61.
Fibre-optic components fabricated on the same substrate as integrated circuits are important for future high-speed communications. One industry response has been the costly push to develop indium phosphide (InP) electronics. However, for fabrication simplicity, reliability and cost, gallium arsenide (GaAs) remains the established technology for integrated optoelectronics. Unfortunately, the GaAs bandgap wavelength (0.85 microm) is far too short for fibre optics at 1.3-1.5 microm. This has led to work on materials that have a large lattice mismatch on GaAs. Here we demonstrate the first light-emitting diode (LED) that emits at 1.5 microm fibre-optic wavelengths in GaAs using optical transitions from arsenic antisite (As(Ga)) deep levels. This is an enabling technology for fibre-optic components that are lattice-matched to GaAs integrated circuits. We present experimental results showing significant internal optical power (24 mW) and speed (in terahertz) from GaAs optical emitters using deep-level transitions. Finally, we present theory showing the ultimate limit to the efficiency-bandwidth product of semiconductor deep-level optical emitters. 相似文献
62.
Mandeep M. Sahani Tarek M. Daoud Ramin Sam Jerry Andrews Yuk Lun Cheng Carl M. Kjellstrand Todd S. Ing 《Hemodialysis international. International Symposium on Home Hemodialysis》2001,5(1):92-96
An aggressive dialysis in a grossly azotemic patient, especially one with severe metabolic acidosis, can lead to dialysis disequilibrium syndrome (DDS). Mild forms present as nausea, vomiting, restlessness, and headache. Severe manifestations include seizures, obtundation, coma, and even death. This clinical picture is caused by cerebral edema induced by one or more of the following mechanisms:
- 相似文献
63.
Roberto Passerone Jerry R. Burch Alberto L. Sangiovanni-Vincentelli 《Formal Methods in System Design》2007,31(1):1-33
Embedded systems are electronic devices that function in the context of a real environment, by sensing and reacting to a set
of stimuli. Because of their close interaction with the environment, and to simplify their design, different parts of an embedded
system are best described using different notations and different techniques. In this case, we say that the system is heterogeneous. We informally refer to the notation and the rules that are used to specify and verify the elements of heterogeneous systems
and their collective behavior as a model of computation. In this paper, we consider different classes of relationships between models of computation and discuss their preservation
properties with respect to the model's refinement relation and composition operator. In particular, we focus on abstraction
and refinement relationships in the form of abstract interpretations and introduce the notion of conservative approximation. We show that, unlike abstract interpretations, conservative approximations preserve refinement verification results from
an abstract to a concrete model while avoiding false positives. We also characterize the relationship between abstract interpretations
and conservative approximations, and derive necessary and sufficient conditions to obtain a conservative approximation from
a pair of abstract interpretations. In addition, we use the inverse of a conservative approximation to identify components
that can be used indifferently in several models, thus enabling reuse across models of computation. The concepts described
in this paper are illustrated with examples from continuous time and discrete time models of computation. 相似文献
64.
New results about the centroid of an interval type-2 fuzzy set, including the centroid of a fuzzy granule 总被引:1,自引:0,他引:1
The centroid of an interval type-2 fuzzy set (IT2 FS) provides a measure of the uncertainty of such a FS. Its calculation is very widely used in interval type-2 fuzzy logic systems. In this paper, we present properties about the centroid of an IT2 FS. We also illustrate many of the general results for a T2 fuzzy granule (FG) in order to develop some understanding about the uncertainty of the FG in terms of its vertical and horizontal dimensions. At present, the T2 FG is the only IT2 FS for which it is possible to obtain closed-form formulas for the centroid, and those formulas are in this paper. 相似文献
65.
Advances in type-2 fuzzy sets and systems 总被引:3,自引:0,他引:3
Jerry M. Mendel 《Information Sciences》2007,177(1):84-110
66.
Matus-Amat Patricia; Higgins Emily A.; Sprunger David; Wright-Hardesty Karli; Rudy Jerry W. 《Canadian Metallurgical Quarterly》2007,121(4):721
The authors used 3-phase context preexposure facilitation methodology to study the contribution of N-methyl-D-aspartate (NMDA) receptors in dorsal hippocampus (DH) and the basal lateral region of the amygdala (BLA) to (a) acquisition of the context memory, (b) retrieval of the context memory, (c) acquisition of context-shock association, and (d) retrieval of the context-shock association. The NMDA receptor antagonist D-2-amino-5 phosphonopentanoic acid (D-AP5) was injected into either the DH or BLA prior to (a) the context preexposure phase, (b) the immediate shock phase, or (c) the test for contextual fear. Antagonizing NMDA receptors in the DH impaired the acquisition of the context memory but did not affect its retrieval or retrieval of the fear memory. Antagonizing NMDA receptors with D-AP5 in the BLA impaired acquisition of the context-shock association but had no effect on the expression of fear. However, both DL-AP5 and L-AP5 reduced the expression of fear when they were injected into the amygdala prior to testing for contextual fear. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
67.
Magdalena M. Czyrnek-Delêtre Alessandro Chiodi Jerry D. Murphy Brian P. Ó Gallachóir 《Clean Technologies and Environmental Policy》2016,18(6):1745-1758
The greenhouse gases (GHG) emissions from land-use change are of particular concern for land-based biofuels. Emissions avoided by substituting fossil fuels with biofuels may be offset by emissions from direct and indirect land-use changes (LUC). There is an urgent need to investigate what impact land-use change emissions may have on the expansion of bioenergy and biofuels, in the context of EU mitigation policies. This paper focuses on Ireland, which faces a number of challenges in delivering its renewable energy and GHG reduction targets. The Irish TIMES energy systems model was used to assess the impact of a range of land-use change emissions’ levels on the evolution of Ireland’s low-carbon energy system. A reference scenario was developed where LUC is ignored and Ireland achieves a least-cost low-carbon energy system by 2050. If high indirect land-use change (ILUC) emissions are included, this results in a decrease by 30 % in bioenergy and a 68 % increase in marginal abatement costs by 2050. Hydrogen is used instead of bioenergy in the freight sector in this scenario, while private cars are fuelled by renewable electricity. If GHG emissions from ILUC were considered less severe, indigenous grass biomethane becomes the key biofuel representing 31 % of total bioenergy consumption. This is in line with recent research in Ireland of the key role that grass biomethane can play. 相似文献
68.
基于模型的构件软件修改影响分析 总被引:1,自引:1,他引:0
基于构件的软件构建方法目前被广泛使用在软件开发中,用于减少软件开发的工程成本和加快软件开发进度.面向构件的系统主要由第三方提供的可重用构件或者内建的可重用构件组成,因此,系统的质量好坏和维护的难易程度依赖于构件的品质.一个软件修改会给其他构件甚至整个系统带来影响,而修改影响分析是控制和消除这类影响的有效手段.然而,现有的研究很少涉及构件软件的修改影响分析,尤其缺少对系统层面的修改影响分析研究.提出了一种基于模型的系统化修改影响分析方法,该方法的基本思路是:首先提出构件及系统层面的修改影响分析模型,然后根据分析模型分别从构件和系统两个层面对构件软件修改前后的版本进行修改识别,并且利用“防火墙”方法进行影响分析.理论分析和实验结果表明,该方法是可行的,也是有效的. 相似文献
69.
70.
Inverse gas chromatography (IGC) has seen wide application in the characterization of molten polymers, fibrous materials,
and natural products, such as proteins and carbohydrates, over the past fifteen years. This study describes a relatively simple
IGC technique for evaluating solute-solvent interactions using a refined soybean oil as a solvent. Utilizing soybean columns
that are 5–20% by weight of the inert support has allowed the determination of a number of thermodynamic solution parameters
for 22 solute-solvent pairs in the temperature range of 55–125°C. Weight and mole fraction activity coefficients, along with
Henry's Law constants at infinite dilution, are presented for six solute classes. In general, activity coefficients increase
with carbon number for n-alkanes, alkyl-substituted benzenes, and n-alkanoic acids at all temperatures investigated, while
the reverse is found for the n-alkanols. The activity coefficient data indicate that aromatic solutes, chlorinated hydrocarbons,
ketones, and cyclohexane can readily dissolve soybean oil. Calculated heats of mixing for n-alkanols were found to be positive
(to 2.84 kcal/mole) while recorded enthalpic interactions were weak for aromatic solutes, lower alkanes, and chlorinated hydrocarbons.
The relevance of the above data to such problems as oil dissolution and solvent devolatilization are discussed.
Presented at the American Oil Chemists' Society Annual Meeting in Phoenix, Arizona, in May 1988. 相似文献