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21.
22.
A new polythiophene containing a cholesteryl side chain in the -position was chemically polymerised in nitromethane/carbontetrachloride using FeCl3 as the oxidizing agent. Polymerisation was also achieved by constant current electrolysis in dichloromethane. Subsequently, conducting copolymers of thiophene-3-yl acetic acid cholesteryl ester (CM), PCM1 (obtained from chemical polymerisation method) and PCM4 (obtained from constant current electrolysis) with pyrrole were synthesized using p-toluene sulfonic acid and sodium dodecyl sulfate as the supporting electrolytes via constant potential electrolyses. Characterizations of the samples were performed by CV, FTIR, NMR, DSC, TGA and SEM analyses. Electrical conductivities were measured by the four-probe technique. 相似文献
23.
Burstein Marcy; Stanger Catherine; Kamon Jody; Dumenci Levent 《Canadian Metallurgical Quarterly》2006,20(2):97
A structural model accounting for child internalizing problems in substance-abusing families was tested. Parents receiving substance abuse treatment (N = 242) completed forms about children between the ages of 6 and 18 who resided in their home. The effects of parent gender, child gender, and child age were controlled. Negative parenting was examined as a mediator between parent internalizing and externalizing problems and child anxiety and affective problems using path analysis. Negative parenting mediated relations only between parent internalizing problems and child affective problems. High-positive involvement moderated relations between parent externalizing problems and child internalizing problems. Relations between parent externalizing problems and child anxiety and affective problems were significant only among families in which high-positive involvement was present. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
24.
Electroinitiated cationic copolymerizations of indene-4-methoxystyrene and indene-β-bromostyrene monomer couples were investigated in dichloromethane by constant potential electrolysis. Copolymer compositions were determined by i.r. spectroscopy and reactivity ratios for the monomers were calculated according to integrated Lewis-Mayo equation. The composition of copolymers and the reactivity ratios were discussed in terms of anodic peak potentials of monomers. 相似文献
25.
A class of adaptive directional image smoothing filters 总被引:3,自引:0,他引:3
The gray level distribution around a pixel of an image usually tends to be more coherent in some directions compared to other directions. The idea of adaptive directional filtering is to estimate the direction of higher coherence around each pixel location and then to employ a window which approximates a line segment in that direction. Hence, the details of the image may be preserved while maintaining a satisfactory level of noise suppression performance. In this paper we describe a class of adaptive directional image smoothing filters based on generalized Gaussian distributions. We propose a measure of spread for the pixel values based on the maximum likelihood estimate of a scale parameter involved in the generalized Gaussian distribution. Several experimental results indicate a significant improvement compared to some standard filters. 相似文献
26.
Levent Kayalar 《Forschung im Ingenieurwesen》1969,35(5):157-167
Zusammenfassung Es wurde der Einflu? des Turbulenzgrads Tu der Anstr?mung auf den W?rmeübergang in der Umgebung des Staupunkts eines Kreiszylinders theoretisch und experimentell untersucht.
Dabei ?nderte man im Versuch den Turbulenzgrad der Anstr?mung durch Verwenden verschiedener Gitter von Tu=0,8 bis 5,2%. Die Messungen fanden bei kleinen Machzahlen (Ma<0,1) und bei Reynoldszahlen vonRe
D=0,8·105 bis 1,12·105 statt. Um den Mechanismus des W?rmeübergangs in Abh?ngigkeit vom Turbulenzgrad theoretisch zu kl?ren, untersuchte man die
laminare Str?mungs- und die Temperaturgrenzschicht an einem Kreiszylinder für den Fall einer gest?rten Au?enstr?mung. Dabei
legte man für die Staupunktstr?mung ein Modell mit St?rwirbeln alternierenden Drehsinns ?hnlich den Taylor-G?rtler-Wirbeln
zugrunde, die in der Grenzschichtstr?mung einer Flüssigkeit l?ngs einer konkaven Wand entstehen. Die Integration der Grenzschichtgleichungen
führt zu der Erkenntnis, da? ?nderungen der Wandschubspannung und des W?rmeübergangs nur von sekund?ren Effekten verursacht
werden k?nnen und somit vom Turbulenzgrad der Str?mung sowie von der Wellenl?nge der St?rungen abh?ngen. In übereinstimmung
mit den experimentellen Ergebnissen zeigen die theoretischen Rechnungen eine betr?chtliche Zunahme der W?rmeübergangs- und
der Wandschubspannungswerte mit wachsendem Turbulenzgrad der Str?mung.
Gekürzte Fassung der von der Fakult?t für Maschinenbau und Elektrotechnik der Technischen Universit?t Braunschweig im Jahr
1968 genehmigten gleichnamigen Dissertation des Verfassers. Die ausführliche Fassung liegt als Bericht des Instituts für Str?mungsmechanik
der Technischen Universit?t Braunschweig von [12]. Die Dissertation entstand w?hrend eines vierj?hrigen Studienaufenthaltes
(1964 bis 1968) des Verfassers unter Betreuung durch Prof. Dr.-Ing.K. Gersten am genannten Institut (Leiter Prof. Dr.-Ing. E. h. Dr. phil.H. Schlichting). 相似文献
27.
Levent Ballice 《Fuel》2003,82(11):1317-1321
The volumetric swelling procedure was applied to Göynük and Beypazar? oil shales from Turkey by using 10 solvents and the cross-linking in the macromolecular network of oil shales were investigated using this technique. Results from solvent swelling measurements show that the volumetric solvent swelling of oil shales samples roughly follows the regular solution theory. The theory of solvent swelling of cross-linked polymers developed Flory-Rehner and extension of this theory by Kovac-Peppas was used to calculate number average molecular weight per cross-link of kerogen structure in oil shale samples. Results indicate no remarkable difference between values for Göynük oil shale (Kerogen Type I) and Beypazar? oil shale (Kerogen Type II). 相似文献
28.
Capacitive micromachined ultrasonic transducers with diffraction-based integrated optical displacement detection 总被引:1,自引:0,他引:1
Hall NA Lee W Degertekin FL 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2003,50(11):1570-1580
Capacitive detection limits the performance of capacitive micromachined ultrasonic transducers (CMUTs) by providing poor sensitivity below megahertz frequencies and limiting acoustic power output by imposing constraints on the membrane-substrate gap height. In this paper, an integrated optical interferometric detection method for CMUTs, which provides high displacement sensitivity independent of operation frequency and device capacitance, is reported. The method also enables optoelectronics integration in a small volume and provides optoelectronic isolation between transmit and receive electronics. Implementation of the method involves fabricating CMUTs on transparent substrates and shaping the electrode under each individual CMUT membrane in the form of an optical diffraction grating. Each CMUT membrane thus forms a phase-sensitive optical diffraction grating structure that is used to measure membrane displacements down to 2/spl times/10/sup -4/ /spl Aring///spl radic/Hz level in the dc to 2-MHz range. Test devices are fabricated on quartz substrates, and ultrasonic array imaging in air is performed using a single 4-mm square CMUT consisting of 19/spl times/19 array of membranes operating at 750 kHz. 相似文献
29.
Kaan Sevki Kavak Orhan Tatar John Piper Fikret Kocbulut B. Levent Mesci 《International journal of remote sensing》2013,34(17):4507-4524
The junction between the East Anatolian and the Dead Sea fault zones lies close to an unstable F: Transform fault (FFF) triple junction where the African, Eurasian and Arabian plates meet in south-eastern Turkey. The Karasu Basin is an ephemeral rifted structure located close to the junction of these plate boundaries and is expressed by a range of tectono-morphological features. This study uses remote sensing to define tectonic structures and discriminate volcanic rocks linked to rifting within the basin using Landsat Enhanced Thematic Mapper Plus (ETM+) imagery. Prior to advanced image processing stages, images were corrected to eliminate atmospheric scattering effects and determine the best band combination for multi-spectral processing techniques based on statistical methods. Following pre-processing stages, edge detection filters were applied to derive tectonic structures defining the basin. The Brovey transformation, a statistical data merging method, was used to combine reflective multi-spectral bands with the Landsat ETM+?panchromatic band. This method fuses higher spatial data with data of lower spatial value. The western margin of the Karasu Basin is defined by the left-lateral Amanos Fault Zone with a contemporary motion (c. –0.4 mm a?1) probably accommodating most of the left-lateral strike-slip motion between Arabian and African plates on the northern continuation of the Dead Sea Fault Zone. The rift zone has been the site of extensive recent volcanism concentrated within the Brunhes Chron (<0.78 Ma) and linked to fault block rotations between the intracontinental master faults. The boundaries of this activity are defined here using a regolith mapping technique. 相似文献
30.