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排序方式: 共有985条查询结果,搜索用时 18 毫秒
1.
The thermal properties of a magnesium aluminium silicate (MAS) glass ceramic matrix composite reinforced by SiC (Nicalon)
fibres have been investigated before and after heat treatment in the temperature range 600–1,200 °C. Within this temperature
range, during the heat treatment at lower temperatures such as 600 and 700 °C, the oxidation of the carbon layer occurred
and mixture of silicon and carbon was formed in the interface. This results in a decrease in thermal diffusivity values. After
heat treatment at the temperatures higher than 1,000 °C, the carbon layer was thickened and resulted in the higher thermal
diffusivity values. 相似文献
2.
Yilmaz Muslu 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1991,51(4):449-460
A dispersed flow model previously developed to study substrate utilization in unsaturated media was experimentally verified and its practical application was considered. For this purpose, measurements were made using tap water and a synthetic feed solution. The importance of the change in fluid regime as regards to the simultaneous transport and reaction within biological filters were demonstrated. The effect of drop formation and the breakage of liquid jets inside the filters on substrate utilization was also shown. 相似文献
3.
DePriest C.M. Yilmaz T. Braun A. Abeles J. Delfyett P.J. Jr. 《Quantum Electronics, IEEE Journal of》2002,38(4):380-389
We report on the development of an ultralow-noise, external-cavity, actively mode-locked semiconductor diode laser for application in next-generation photonic sampling systems. A summary of harmonically mode-locked noise characteristics in a 65-MHz ring cavity is presented through the range of pulse repetition frequencies between 130 MHz and 8.3 GHz (2nd-128th harmonic). Important implications regarding the use of gain-versus-loss modulation as the active modelocking mechanisms are discussed. We also report what are, to our knowledge, the lowest noise characteristics achieved to date for a semiconductor diode laser operating at 10 GHz. Individually optimized results of 0.12% rms amplitude noise (10 Hz-10 MHz), and 43 fs rms residual phase jitter (10 Hz-10 MHz) provide a theoretical resolution of 8.6 bits in a 10-GSPS optical analog-to-digital converter. We have also achieved dispersion-compensated pulsewidths; as short as 1.2 ps, and shown successful operation of a novel phase-locked-loop capable of reducing the rms; residual phase noise by as much as 91% within its response bandwidth. Finally, the first measurements of residual phase noise out to the Nyquist frequency (5 GHz) are presented, providing an upper bound on the rms residual phase jitter of 121 fs (10 Hz-5 GHz) 相似文献
4.
Huriye Karalayan Hü seyin Afsar Cemile Yan Naciye Yilmaz 《Petroleum Science and Technology》1992,10(10):1641-1651
The flotation of oxidized Amasra Coal which was collected between 1973-1978 and, stored in the atmospheric conditions was examined In this work. Coal samples were fractioned by wet screening to +0.560 mm, -0.500 + 0.140 mm, -0.140 mm particle sizes and first fraction was ground to -0.560 mm before flotation. Motorin and pine oil which had been heated at 125° C for 5 hours were used ns flotation reagents. The influence of impeller speed, aeration rate, solid concent of the pulp, reagent amounts were examined and optimum values were determined. Increase of the pine oil amount added to the pulp, increased the coal. recovery on the flotation of this oxidized coal. 相似文献
5.
T. D. Dzhafarov S. S. Yesilkaya N. Yilmaz Canli M. Caliskan 《Solar Energy Materials & Solar Cells》2005,85(3):371-383
The effective diffusion coefficients of Cu for thermal and photodiffusion in the CdTe films have been estimated from resistivity versus duration of thermal or photoannealing curves. In the temperature range 60–200°C the effective coefficient of thermal diffusion (Dt) and photodiffusion (Dph) are described as Dt=7.3×10−7exp(−0.33/kT) and Dph=4.7×10−8exp(−0.20/kT).It is found that the diffusion doping of CdTe thin films by Cu at 400°C results in a sharp decrease of resistivity up to 7 orders of magnitude of p-type material, depending on thickness of Cu film. The comparative study of performance of CdTe(Cu)/CdS and CdTe/CdS cells has been studied. It is shown that the diffusion doping of CdTe film by Cu increases efficiency of CdTe(Cu)/CdS cells from 0.9% to 6.8%. The degradation of photovoltaic parameters of CdTe(Cu)/CdS cell, during testing under forward and reverse bias at room temperature, proceeds at a larger rate than those of CdTe/CdS cell without Cu. The degradation of performance of CdTe(Cu)/CdS cells is tentatively assigned to electrodiffusion of Cu in CdTe, resulting in redistribution of concentration of Cu-related centers in CdTe film and heterojunction region. 相似文献
6.
A new monomer, octa(thiophenephenyl)silsesquioxane (OThiophenePS) was synthesized via click chemistry. The chemical structure of OThiophenePS was characterized by nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FT-IR) spectroscopies. Electrochemical polymerization of pyrrole with OThiophenePS was performed resulting in polypyrrole-attached, polyhedral oligomeric silsesquioxane (OPS–PPy). The spectroelectrochemical studies show that the electrochromic properties of (OPS–PPy) are superior to those of polypyrrole (PPy). This great improvement can be attributed to the more accessible doping sites and the facile ion movement during the redox switching brought by the loose packing of the PPy chains. 相似文献
7.
Veysel T. Yilmaz Evrim Senel Canan Kazak 《Journal of Inorganic and Organometallic Polymers and Materials》2008,18(3):407-413
The reaction of [Cu(sac)2(H2O)4] · 2H2O with 2-methylpyrazine (mpyz) leads two complexes, concomitant crystallization of a mononuclear complex [Cu(sac)2(mpyz)(H2O)2] (1) and a polymeric complex [Cu(sac)2(μ-mpyz)]n (2). Both complexes have been characterized by elemental analyses, magnetic measurements, FT-IR and ESR, TG-DTA and single-crystal
X-ray diffraction analyses. Single-crystal X-ray analyses show that complex 1 consists of discrete molecules in which the copper(II) ions exhibits a square-pyramidal coordination geometry. The individual
molecules of 1 are connected into a hydrogen-bonded chain structure, which is further assembled to form a three-dimensional network by π–π stacking interactions.
Complex 2 is an 1D coordination polymer in which copper(II) centers are bridged by the mpyz ligand. The chains are further assembled
to form two-dimensional frameworks by π–π and C–H···π stacking interactions. 相似文献
8.
9.
Water soluble carboxylic acids have been used as corrosion inhibitors. They remain largely soluble after curing in cement for up to 90d. Corrosion current measurements are presented showing malonic acid, a dicarboxylic acid, to be a very effective corrosion inhibitor even in the presence of 2.5 wt % chloride. Unfortunately, it has an initial retarding effect on the set of Portland cement. The investigation suggests that corrosion inhibitors based on carboxylic acids remain a fruitful field of investigation. 相似文献
10.
It is commonly accepted that an individual's beliefs and actions are based on his or her assessment and perceptions of the world. In order to determine what practices an individual is likely to follow at any given time, it is necessary to understand the individual's behavioral intention in a given circumstance. From an Information Technology perspective, a software development professional's belief systems are potentially the basis for the adoption and implementation of new and innovative work practices and processes. In this article, we explore the belief systems of software development professionals in order to understand the beliefs underlying intention and practice, and we seek answers about how they adopt or reject new and innovative software development processes and practices. The results point out a strong influence of past experiences, personality types, and repeated behavior on current software development processes and practices in industrial settings. 相似文献