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31.
Gail H. Marcus 《Petroleum Science and Technology》1987,5(4):387-439
This paper documents and analyzes recent trends in Federal energy research and development programs. In light of the marketplace philosophy of the present Administration, the possible benefits of a strong Federal research program versus the potential advantages of relying on private sector research programs to develop new technology alternatives are analyzed in some detail. The impacts of the Reagan budget cuts and other initiatives on several major energy programs, including nuclear power, photovoltaics, and conservation, are also analyzed. This analysis reveals some of the difficulties inherent in attempting to project the consequences of particular policy decisions in a complex and changing environment, and identifies some of the problems of trying to evaluate the success of particular programs or actions on a limited time scale. 相似文献
32.
Rintala Diana H.; Young Mary Ellen; Hart Karen A.; Fuhrer Marcus J. 《Canadian Metallurgical Quarterly》1994,39(1):15
140 adults (aged 19–77 yrs) were randomly selected from a sampling frame of 661 persons with spinal cord injury. They completed a questionnaire assessing amount of social support, degree of reciprocity with supporters, and satisfaction with relationships with supporters; the Center for Epidemiologic Studies Depression Scale; a self-report version of the Functional Independence Measure; and the Craig Handicap Assessment and Reporting Technique. A physician assessed the degree of paralytic impairment by means of the ASIA Total Motor Index Score. Relationships in which the supporter gave more than the participant were associated with more satisfaction with the relationship and more social support. The number of reciprocal relationships was positively associated with more desirable outcomes in the handicap dimensions of mobility, occupation, social integration, and economic self-sufficiency. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
33.
M Kü?ükaydin H Okur C Turan M I?er M Zorlu A Kazez 《Canadian Metallurgical Quarterly》1993,159(9):487-489
OBJECTIVE: To describe our experience with Swenson's operation for Hirschsprung's disease done during the neonatal period. DESIGN: Retrospective study. SETTING: University department of paediatric surgery. SUBJECTS: 10 Neonates with Hirschsprung's disease. INTERVENTIONS: Rectosigmoidectomy and pull through (Swenson's operation), with covering transverse colostomy. MAIN OUTCOME MEASURES: Mortality, morbidity, and continence. RESULTS: The median age at definitive operation was 25 days (range 15-35). There was one late death three weeks after discharge from hospital of respiratory and cardiac failure. Two patients presented with caecal perforation and two with intestinal obstruction; in all four Hirschsprung's disease was diagnosed on frozen section, a transverse colostomy was done, and the Swenson's operation was done electively. The other six were diagnosed by barium enema examination and biopsy, and underwent total bowel irrigation followed by Swenson's operation and transverse colostomy. The colostomies were closed three to four weeks later. There were no postoperative complications. All nine surviving patients were continent (3-4 stools/day), at a mean (SD) follow up of 21 (5) months. CONCLUSION: With the current high standards of anaesthesia and neonatal intensive care, and an experienced surgeon, Swenson's operation for neonatal Hirschsprung's disease is safe and the procedure of choice for this condition. 相似文献
34.
Olivier Klein Steve Donovan Martin Dressel George Grüner 《Journal of Infrared, Millimeter and Terahertz Waves》1993,14(12):2423-2457
This report reviews the analysis used to extract the complex conductivity of a compound from a microwave cavity perturbation measurement. We intend to present a generalized treatment valid for any spheroidally shaped sample of arbitrary conductivity which is placed at either the electric or magnetic field antinode of the cavity. To begin with, we establish the relationship between the measured parameters and the conductivity for a spherical sample. Next, we extend these results to the case of spheroids; and for the first time, we cover all different configurations that one can possibly use to study an arbitrary conducting sample inside a cavity: in particular, all possible orientations of the sample with respect to the applied field are solved. 相似文献
35.
Chaichanavong P. Marcus B.H. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2003,49(5):1231-1250
A constrained system is presented by a finite-state labeled graph. For such systems, we focus on block-type-decodable encoders, comprising three classes known as block, block-decodable, and deterministic encoders. Franaszek (1968) gives a sufficient condition which guarantees the equality of the optimal rates of block-decodable and deterministic encoders for the same block length. We introduce another sufficient condition, called the straight-line condition, which yields the same result. Run-length limited RLL(d,k) and maximum transition run MTR(j,k) constraints are shown to satisfy both conditions. In general, block-type-decodable encoders are constructed by choosing a subset of states of the graph to be used as encoder states. Such a subset is known as a set of principal states. For each type of encoder and each block length, a natural problem is to find a set of principal states which maximizes the code rate. We show how to compute the asymptotically optimal sets of principal states for deterministic encoders and how they are related to the case of large but finite block lengths. We give optimal sets of principal states for MTR(j,k)-block-type-decodable encoders for all codeword lengths. Finally we compare the code rate of nonreturn to zero inverted (NRZI) encoders to that of corresponding nonreturn to zero (NRZ) and signed NRZI encoders. 相似文献
36.
37.
Droplet formation on Si surfaces bombarded by 10 keV beams from a liquid metal indium ion source has been observed. It has been verified that excess indium is transported in the ion beam, probably in the form of charged droplets. SIMS, SEM and RBS techniques have been used to study the distribution of droplets at the surface. At the specified ion source operating conditions, equilibrium droplet coverage is of the order of 25%. Individual droplets have an average diameter of 0.35 ωm and an average height of 2.2 nm. At a bombardment current density of 0.1 mA cm?2, equilibrium coverage is reached in about 1 s. 相似文献
38.
39.
The operation of a petroleum refinery at TÜPRA
. Tütünçiftlik was assessed using the pinch-design method. By making use of heat integration in the heat-exchange network, appreciable amounts of energy can be saved as a result of a capital investment having a pay-back period of about 6·5 months. 相似文献
40.
Rakel Lindström Henri Groult Sandrine Zanna Philippe Marcus 《Electrochimica acta》2006,51(23):5001-5011
In order to produce thin films of crystalline V2O5, vanadium metal was thermally oxidised at 500 °C under oxygen pressures between 250 and 1000 mbar for 1-5 min. The oxide films were characterised by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), X-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). The lithium intercalation performance of the oxide films was investigated by cyclic voltammetry (CV), chronopotentiometry and electrochemical impedance spectroscopy (EIS). It was shown that the composition, the crystallinity and the related lithium intercalation properties of the thin oxide films were critically dependent on the oxidation conditions. The formation of crystalline V2O5 films was stimulated by higher oxygen pressure and longer oxidation time. Exposure for 5 min at 750 mbar O2 at 500 °C resulted in a surface oxide film composed of V2O5, and consisting of crystallites up to 200 nm in lateral size. The thickness of the layer was about 100 nm. This V2O5 oxide film was found to have good cycling performance in a potential window between 3.8 and 2.8 V, with a stable capacity of 117 ± 10 mAh/g at an applied current density of 3.4 μA/cm2. The diffusion coefficients corresponding to the two plateaus at 3.4 and 3.2 V were determined from the impedance measurements to (5.2 and 3.0) × 10−13 cm2 s−1, respectively. Beneath the V2O5 layer, lower oxides (mainly VO2) were found close to the metal. At lower oxygen pressure and shorter exposure times, the oxide films were less crystalline and the amount of V4+ increased in the surface oxide film, as revealed by XPS. At intermediate oxygen pressures and exposure times a mixture of crystalline V2O5 and V6O13 was found in the oxide film. 相似文献