排序方式: 共有39条查询结果,搜索用时 15 毫秒
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J. Rantala J. Hartikainen J. Jaarinen 《Applied Physics A: Materials Science & Processing》1990,50(5):465-471
In this paper we describe the use of thermal microscopes in measuring the lengths of vertical cracks in silicon nitride. Results of theoretical calculations for temperature profiles in samples near the end of the cracks are demonstrated. These calculations showed that the effect of the crack decreases to a non-measurable level at distances of about 10 m from the end of the crack. Experimental measurements showed that thermally obtained crack lengths were at least 34% longer than those that were optically measured. The obtained crack length was independent of the heat modulation frequency used. 相似文献
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Lecithin/propanol-based microemulsions used as media for a cholesterol oxidase-catalyzed reaction 总被引:1,自引:0,他引:1
Reverse micelles, Winsor III and IV systems were examined as reaction media for the enzymatic conversion of cholesterol to cholestenone by cholesterol oxidase at 298.2 K. The micelles and the microemulsions, stabilized by soybean lecithin and ethanol or 1-propanol as cosolvent, were characterized with respect to phase behavior and distribution of 1-propanol between the phases of the Winsor III systems. The used oils were dodecane, tetradecane, and hexadecane. The Winsor IV systems and the surfactant-rich phase in the Winsor III systems exhibit bicontinuous structures. The reaction yield for the enzymatic conversion performed in a Winsor IV system was much higher than in a Winsor III system or in reverse micelles. 相似文献
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Partition and determination of cadmium, copper, lead and zinc in marine suspended particulate matter 总被引:1,自引:0,他引:1
R T Rantala D H Loring 《International journal of environmental analytical chemistry》1985,19(3):165-173
A method for the determination of Cd, Cu, Pb, and Zn in the total and acetic acid (25%) soluble fraction of suspended particulate matter collected on Nuclepore membranes is described. The acetic acid leaching was carried out in a modified Millipore vacuum filtration apparatus. The total sample and the acetic insoluble fraction were decomposed in teflon bombs with HF/aqua regia. Flame or graphite furnace AAS was used for metal determinations. Sequential acetic acid extractions (3) show that on the average 76.4-92.0% of the metals are removed with the first extraction. Cadmium is potentially most easily available to biota with 90.4% of the total metal concentration located in the acetic acid soluble fraction. 相似文献
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Mikko Keränen Marcin Gnyba Paavo Raerinne Terho Kololuoma Arto Maaninen Juha T. Rantala 《Journal of Sol-Gel Science and Technology》2004,31(1-3):369-372
Sol–gel adhesive material for isostatic hotpressing lamination process was synthesized using 3-aminopropyltrimethoxysilane (APTES), 3-glycidyloxypropyltrimethoxysilane (GPTS) and methacryloxypropyltrimethoxysilane (MPTS) as precursors. Reaction dynamics between APTES and GPTS was followed on-line with Raman spectroscopy. The lamination process was optimized by varying hotpressing times and pressures at the constant temperature. Mechanical shear strength properties were found to be excellent for studied composition, 25–30 kg/cm2 at its best. One possible application of laminated polycarbonate (PC) structure is a soldier helmet visor. Therefore, the ballistic protection properties were tested by shooting with 1.1 gram standard fragment, and determining the v50 velocity value, which corresponds to 50% perforation. The laminated structure gave 5.7% better protection compared with the solid polycarbonate. The laminated components were found to have high optical transparency at the visible wavelengths as well as high environmental stability. 相似文献
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Tapio T. Rantala 《Applied Physics A: Materials Science & Processing》1990,50(2):215-220
Simple models for the thermally activated dissociation reaction of silane and silicon growth on a polycrystalline silicon surface are presented. The models are fitted to recent experimental molecular beam scattering data for the low-pressure reactive sticking coefficient. Thermally activated few-step models fit the data reasonably well, and thus, we are able to explain the temperature and pressure dependencies of the observed deposition rate. 相似文献
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Ville Nieminen Markus Karjalainen Katri Salminen Jussi Rantala Anton Kontunen Poika Isokoski Philipp Müller Pasi Kallio Veikko Surakka Jukka Lekkala 《International Journal for Ion Mobility Spectrometry》2018,21(3):71-80
Production of easily controllable and measurable odor stimuli is needed when studying human olfaction, olfaction-related physiology and psychological reactions to odors. Controlled odor producing instruments are called olfactometers. For testing and calibrating new olfactometers or sensor arrays, a reliable input signal has to be produced to verify their accurate functionality. A common input signal in various olfactometers has been the use of volatile organic compounds (VOCs) in gaseous form. We present a compact olfactometer able to produce controlled continuous odor stimuli from three individual channels. For measuring the output gas flow, we used a ChemPro 100i (Environics, Finland) device that is based on aspiration ion mobility spectrometry (aIMS). IMS is a robust and sensitive method for measuring VOCs and is used especially in detecting toxic industrial chemicals and chemical warfare agents, but the technology is also suitable for other olfactory-related applications. The olfactometer was used to produce synthetic jasmine scent using three main odor components from jasmine oil and all the components were diluted using propylene glycol. The dilutions were supplied to the system using programmable syringe pumps, which guided the dilutions to individual evaporation units. We conducted experiments to verify the functionality of our olfactometer. Analysis of the ChemPro100i data showed that olfactometer can use different odor components to produce continuous, stable output flows with controlled concentrations. 相似文献
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A method is described for the decomposition of silicate materials in 20-tal Tefion- TFE bombs by using a domestic microwave oven. A domestic pressure cooker was used as a precautionary device to contain acid fumes. Total decomposition of the reference materials, marine sediment MESS-1 and granite G-2, was achieved in 60 s with a mixture of hydrofluoric acid and aqua regia. By using flame or graphite-furnace atomic absorption spectrometry, recoveries greater than 97% were obtained for aluminium, chromium and zinc and greater than 93% for silicon in the samples and for silicon in a pure quartz rod. 相似文献