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排序方式: 共有206条查询结果,搜索用时 15 毫秒
1.
Standard Gibbs free energy of formation (ΔGf0), an important property needed in design calculations has been estimated using molar refraction, RM. The linear relationships derived between ΔGf0 and RM tested with the data on 8 series of hydrocarbons at 228 compounds yielded average deviations comparable to the methods cited in recent literature. The method can be used as an alternative to the existing ones, because of its simplicity combined with reasonable accuracy. 相似文献
2.
3.
Scientometrics of the international journal Scientometrics 总被引:4,自引:0,他引:4
An analysis of 1317 papers published in first fifty volumes during 1978 to 2001 of the international journal Scientometrics indicates the heterogeneity of the field with emphasis on scientometric assessment. The study indicates that the US share of papers is constantly on the decline while that of the Netherlands, India, France and Japan is on the rise. The research output is highly scattered as indicated by the average number of papers per institution. The scientometric output is dominated by the single authored papers, however, multi-authored papers are gaining momentum. Similar pattern has been observed for domestic and international collaboration. 相似文献
4.
BV Venkataraman S Dutt J Czekajewski L Nennerfelt C Williams 《Canadian Metallurgical Quarterly》1995,39(3):283-286
A simple method has been developed for continuous monitoring of metabolic activity of an isolated, perfused rat heart by O2/CO2 respirometer. Since respirometer provides vital data on oxygen consumption and carbon dioxide production of a preserved organ on a continuous basis over a long period of time, it will be possible to use this method to monitor viability of not only isolated heart but also any given donor organ under preservation. 相似文献
5.
The effect of heat-ageing on four bituminous roofing membranes, two modified with atactic polypropylene (APP) and two modified
with styrene-butadiene-styrene (SBS) was studied using tensile testing and dynamic mechanical thermals analysis (DMA). The
samples were heated at 80°C for 7, 28, 84 and 168 days and were tensile tested at 23, 0, −10, −20 and −30°C. Each heat-aged
sample was also subjected to thermomechanical testing to find its glass transition temperature T
g
. The results show significant variation in the effect of heat-ageing on tensile strength and elongation of membranes. T
g
values differ with the modifiers and other ingredients of the membranes and are affected by heat-ageing. The influence of
the glass transition zone measured by DMA is also reflected in the tensile test results.
Resume On a étudié l’influence du vieillissement par la chaleur sur quatre membranes d’étanchéité, deux d’entre elles étant traitées par APP (polypropylène atactique) et deux par SBS (styrène de styrène butadiène), à l’aide de l’essai en traction et de l’analyse thermique mécaniques (DMA). Les échantillons ont été chauffés à 80°C pendant 7, 28, 84 et 168 jours et essayés en traction à 23, 0, −10, −20 et −30°C. Chaque échantillon vieilli par la chaleur a été également soumis à un essai thermomécanique pour identifier sa température de passage à l’état vitreux T g . Les résultats montrent des différences importantes dans l’influence de la chaleur sur la résistance en traction et l’allongement des membranes. Les valeurs de T g diffèrent selon les traitements et les autres composants des membranes, et sont affectées par le vieillissement par la chaleur. L’influence de la zone de passage à l’état vitreux mesurée par l’analyse thermique mécainique se traduit aussi dans les résultats de l’essai en traction.相似文献
6.
A good statistical model of speckle formation is useful for designing a good adaptive filter for speckle reduction In ultrasound B-scan images. Previously, statistical models have been used, but they failed to account for the log compression of the echo envelope employed by clinical ultrasound systems. Log-compression helps in reducing the dynamic range of the B-scan Images for display on a monitor as well as enhancing weak backscatters. In this article, statistics of log-compressed echo images, using the K-distribution statistical model for the echo envelope, are used to derive a parameter that can be used to quantify the extent of speckle formation. This speckle quantification can be used with an unsharp masking filter to adaptively reduce speckle. The effectiveness of the filter is demonstrated on images of contrast detail phantoms and on in-vivo abdominal images obtained by a clinical ultrasound system with log-compression. 相似文献
7.
B. Shashank Dutt M. Nani Babu G. Shanthi S. Venugopal G. Sasikala A.K. Bhaduri 《Journal of Nuclear Materials》2012,421(1-3):15-21
Quasistatic fracture behaviour of two heats of modified 9Cr–1Mo steel for steam generator applications have been assessed at 298, 653 and 823 K. J–R curves were established and the elastic–plastic fracture toughness values at 0.2 mm crack extension (J0.2) were determined. The fracture mechanisms were entirely different for the two steels at 298 K, with brittle fracture controlled by cleavage crack initiation in one and ductile fracture in the other by void nucleation and growth. At 653 and 823 K, fracture in both materials was by ductile crack growth. The difference in behaviour between the two steels at 298 K was attributed to the differences in microstructure, distribution and density of inclusions as well as phosphorous contents. 相似文献
8.
Kumawat Piyush Kumar Chaturvedi Nitin Dutt 《Clean Technologies and Environmental Policy》2022,24(1):273-288
Clean Technologies and Environmental Policy - Water is considered a significant resource in process industries. It is essential for planners to target and optimize the use of water as an external... 相似文献
9.
Pradipta Biswas Varun Dutt Pat Langdon 《International journal of human-computer interaction》2016,32(1):23-38
Eye-gaze tracking is traditionally used to analyze ocular parameters for investigating visual psychology, marketing study, behavior analysis, and so on. Currently, eye-gaze trackers are also being used to control electronic interfaces in assistive technology, automobile control, and even consumer electronic products like smartphones and tablets. However, there are not many attempts to combine these two streams of research on active and passive uses of eye-gaze trackers. This article compares a few ocular parameters to estimate users’ cognitive load in eye-gaze-controlled interfaces. It was found that average velocity of a particular type of microsaccadic eye movement called Saccadic Intrusion is most indicative of users’ cognitive load compared to pupil dilation and eye-blink-based parameters. Results from the study can be used to develop new metrics of cognitive load measurement, as well as to design intelligent gaze-controlled interfaces that respond to users’ cognitive load. 相似文献
10.
Morphology controlled synthesis of polyaniline nanostructures using swollen liquid crystal templates
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Preparation of zero‐dimensional and one‐dimensional nanostructures of polyaniline (PANI) were achieved by using swollen liquid crystals (SLCs) as ‘soft' templates. The monomer (aniline) was first entrapped in SLCs by replacing the oil phase (cyclohexane) with a mixture of aniline and cyclohexane. Zero‐dimensional nanostructures of PANI were obtained by thorough mixing of APS with the mesophases. One‐dimensional nanostructures were prepared by allowing slow diffusion of APS through the mesophase. PANI nanostructures were extracted from the mesophase and were characterized by UV‐visible spectroscopy, FTIR spectroscopy, powder X‐ray diffraction, atomic force microscopy, scanning electron microscopy (SEM), and conductivity measurements. A plausible mechanism for the formation of the nanostructures has been proposed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40800. 相似文献