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排序方式: 共有625条查询结果,搜索用时 15 毫秒
1.
Irine Banu Lucy 《Journal of Materials Science》2007,42(14):5875-5879
Capacitance and dielectric loss measurements were carried out using an Al/Cu–GeO2/Al sandwich structure for 0 to 10 vol% Cu films, 120–400 nm thick, deposited at 0.4–1.5 nm/s in the frequency and temperature
range 1–106 Hz and 90–573 K, respectively. The variation of capacitance and dielectric loss with frequency and temperature follows the
Goswami and Goswami model. Capacitance decreases slowly with increasing thickness and also varies with the change in deposition
rate of the cermet film. 相似文献
2.
Almond preferences were produced by giving rats a mixture of almond and sucrose (Experiments 1-4) or saccharin (Experiment 4). A subsequent extinction procedure consisted of either repeated 2-bottle almond versus water tests (Experiment 1) or repeated exposure to almond alone (Experiments 2-4). The main independent variable was whether access to food following a session was given immediately, 30 min later, or 120 min later. No effect of extinction was found in any experiment. An important finding was that varying the delay until food access had no detectable effect. It was concluded that inadvertent flavor-food associations do not maintain preference for the flavor under extinction conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
Button Cathryn M.; Grant Malcolm J.; Hannah T. Edward; Ross Abraham S. 《Canadian Metallurgical Quarterly》1993,25(2):230
Two studies identified and labeled the dimensions that people use to judge others' attitudes. In the 1st study, 50 male and 50 female undergraduates viewed pairs of attitude statements drawn from 1 or 2 large sets. For each pair of statements, Ss judged whether or not a person who agreed with one statement in the pair would be likely to agree with the other. The dimensions of liberalism and traditional values were found to underlie perceived attitudes. Validity was confirmed in a 2nd study with 60 male and 60 female undergraduates who rated the characteristics of hypothetical people who agreed strongly with particular statements. Results suggest that there is a common structure to people's perceptions of others' attitudes. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
Lullo G. McKee A. McLean C.J. Bryce A.C. Button C. Marsh J.H. 《Electronics letters》1994,30(19):1623-1625
Electroabsorption optical modulators have been fabricated on GaInAs/GaInAsP multiquantum well structures whose bandgap had been increased by laser photoabsorption-induced disordering. Modulation depths of 20 dB have been obtained in material which has been bandgap blue shifted by as much as 120 nm, while samples shifted by 80 nm gave depths as high as 27 dB 相似文献
5.
Polyvinyl alcohol (PVA) films containing 10% w/w of a model drug, sulphathiazole, were cast from aqueous solutions and subjected to heat treatment at specific temperatures for known periods of time. Heat treatment at temperatures above the Tg of the PVA films slowed down the rate of drug release from the films. Increasing the temperature of heat treatment from 120°C to 160°C further decreased the rate of drug release. On the other hand, if the heat treatment were conducted at a temperature below the Tg e.g. at 80°C, there were insignificant differences between the release profile of sulphathiazole from heat-treated films and that from untreated films. The duration of heat treatment affected the rate of drug release to a smaller extent compared to the temperature of heat treatment. These results correlated with the heat induced changes in the morphology of, and in the extent of water uptake by the PVA films. 相似文献
6.
The phase behavior of binary blends of acrylonitrile/methyl acrylate/butadiene terpolymer (B210) and poly(ethylene-co-maleic anhydride) (PEMA) was examined based on thermal analysis and optical microscopy. Miscibility of these polymer blends was recognized over a wide range of compositions. The appearance of phase separation during subsequent heatings above the glass transition temperature (Tg) of these blends was associated with a lower critical solution temperature (LCST) behavior. Rheological characteristics such as shear storage modulus (G′), loss modulus (G″) and complex viscosity have been shown to depend on the amount of PEMA in the blend. Mechanical properties including the tensile strength and flexural modulus also were found to be related to the composition of the blend. © 1993 John Wiley & Sons, Inc. 相似文献
7.
A technique based on viscous polymer processing (VPP) was described, which can produce high ceramic content green fibers. PZT-5 ceramic powders were ball milled to get high dispersibility. The slurry prepared for VPP was a composition of PZT-5 powder, PVA binder and glycerin. High ceramic content PZT-5 fibers were extruded with the slurry. The results show that the ceramic powders have fine mean particle size of 0.54 pan, high specific surface area of 3.55 m^2/g and zeta potential of 8.81 mV after 16 h milling. The fibers sintered at 1 280 ℃ for 4 h have pure perovskite structure and grains of 2-5 μm in size, with little pores or cracks. The ultimate tensile strength of sintered fibers is up to 13.84 MPa compared with 2.88 MPa of green fibers. The remnant polarization (Pr) and coercive field (Ec) of the fibers are 50.65 μC/cm^2 and 2.45 kV/mm, respectively. This fiber can withstand an electric field of 9 kV/mm higher than the ceramic (5 kV/mm), which shows high directional and compact qualities. 相似文献
8.
Simulations of extensional flow in microrheometric devices 总被引:1,自引:0,他引:1
Mónica S. N. Oliveira Lucy E. Rodd Gareth H. McKinley Manuel A. Alves 《Microfluidics and nanofluidics》2008,5(6):809-826
We present a detailed numerical study of the flow of a Newtonian fluid through microrheometric devices featuring a sudden
contraction–expansion. This flow configuration is typically used to generate extensional deformations and high strain rates.
The excess pressure drop resulting from the converging and diverging flow is an important dynamic measure to quantify if the
device is intended to be used as a microfluidic extensional rheometer. To explore this idea, we examine the effect of the
contraction length, aspect ratio and Reynolds number on the flow kinematics and resulting pressure field. Analysis of the
computed velocity and pressure fields show that, for typical experimental conditions used in microfluidic devices, the steady
flow is highly three-dimensional with open spiraling vortical structures in the stagnant corner regions. The numerical simulations
of the local kinematics and global pressure drop are in good agreement with experimental results. The device aspect ratio
is shown to have a strong impact on the flow and consequently on the excess pressure drop, which is quantified in terms of
the dimensionless Couette and Bagley correction factors. We suggest an approach for calculating the Bagley correction which
may be especially appropriate for planar microchannels.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
通过XRD、SEM分析和变温、变频条件下的logρ-t测量,对Co-Mn-Ni-O2系热敏材料的logρ-t特性与频率关系进行了研究.CoMn1.4Ni0.6O4尖晶石型氧化物热敏电阻材料的logρ-t特性在一定频率(0.1~1MHz)和温度范围(-70~1000℃),发生了由正温度系数(PTC)向负温度系数(NTC)的转变,且转变点的温度(-70~-10℃)和频率(0.1~1MHz)与材料电阻率相关.根据电导率σ和载流子浓度n、载流子迁移率μ之间的关系,对导电机理作了初步的解释. 相似文献
10.
Lucy Geng 《国外纺织技术(纺织针织服装化纤染整)》2021,(3):I0020-I0022
真金换旧爱,二手奢侈品为啥这么火?近期,部分奢侈品品牌开启新一轮涨价热潮,奢侈品门店外的队伍越排越长,门店内配货的盒子越垒越高,与此相映成趣的是疫情下"叫卖声"火热的二手奢侈直播间。包括寺库、只二、胖虎、红布林及妃鱼在内的国内二手奢侈品平台均入局直播电商,实体门店顾客群更是在线下人流受阻的情况下积极拥抱线上直播. 相似文献