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41.
Arivazhagan L. Nirmal D. Reddy P. Pavan Kumar Ajayan J. Godfrey D. Prajoon P. Ray Ashok 《SILICON》2021,13(9):3039-3046
Silicon - In this paper, AlGaN/GaN High Electron Mobility Transistor (HEMT) with stacked passivation (Diamond/SiN) is proposed and investigated. The implementation of stacked passivation in HEMT... 相似文献
42.
Photoelasticity is a method which yields information on the principal stress difference and orientation in a composite structure. Various problems associated with this technique, especially those concerning the fundamental relationship between the fringe order and the stress, have yet to be investigated. A few studies of this relationship in a universal stress state have been presented, particularly in the field of rubber-to-metal and rubber-to-fabric composites, but no evaluations have so far been made in the field of rubber-to-rubber joints. Applying the photoelastic method, we report our observations on the stress distribution in a natural rubber to natural rubber joint subjected to uniaxial tension. A comparison between the results of experimental photoelastic studies and the corresponding computer modelling has been illustrated. The theoretical displacement pattern of the angular joints of bi-rubber part has also been highlighted. 相似文献
43.
An interfacial grafting radical polymerization method for amphiphilic comb copolymer and shell crosslinked polymer nanocapsules was reported. Macropolyradicals on a water soluble long chain polyamine were generated with hydrogen peroxide in the water phase and subsequent grafting radical polymerization of a vinylic monomer at the water/oil interface proceeded at 65°C. In the presence of a crosslinker, the resulting graft copolymer formed a defined core‐shell structure with hydrophilic aqueous core functionalized by the polyamine and a hydrophobic crosslinked polymer shell. The structure of the core‐shell material was characterized by NMR, FTIR, DSC, TGA, SEM, TEM, and the mechanism of the graft polymerization is proposed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1905–1911, 2007 相似文献
44.
A simple and efficient new method for QRS detection in Electrocardiogram (ECG) is proposed in this paper. Initially data is preprocessed using two stage median filter for removing baseline drift. The second stage enhances the peaks of ECG wave components by using sixth power of signal. The next stage identifies the QRS complex by taking a variable window size. The detection sensitivity (Se) and positive predictivity (+P) of CSE (Common Standards for Quantitative Electrocardiography) measurement database, MIT/BIH (Massachusetts Institute of Technology/Beth Israel Hospital) Arrhythmia database, European ST-T database and QT database are Se 99.51 & +P 99.69%, Se 99.21 & +P 99.34%, Se 99.53 & +P 99.72% and Se 99.87 & +P 99.95% respectively. These four standard databases used to perform QRS detection considered 368 cases, tested 1,006,168 beats and achieved overall average sensitivity 99.52% and positive predictivity 99.69%. The MIT/BIH Noise Stress Test Database also tested by proposed method. 相似文献
45.
46.
Alok Singh Sitaram Dash Mohammed Kamruddin Puthupparampil K. Ajikumar Ashok K. Tyagi Vinjamoor S. Raghunathan Baldev Raj 《Journal of the American Ceramic Society》2002,85(4):927-932
Formation of nanocrystalline calcia from calcite has been studied in situ via transmission electron microscopy. The crystallographic transformation occurred via two mechanisms: the first is by distortion of the cleaved rhombohedron of calcite, formed by {104} planes in hexagonal coordinates, into a cube. This produced a microstructure of oriented, elongated nanocrystals of calcia with planar boundaries. In the second mechanism, the micrometer-sized parent calcite particles broke up into nano-sized grains as the decomposition began, leading to irregularly shaped, randomly oriented nanocrystals of calcia. 相似文献
47.
World consumption of PVC was around 25 MM MT (55 billion pounds) in year 2001, second only to that of low density polyethylene. Only 10% of the PVC produced is classified as specialty PVC resins, while the other 90% is referred to as general purpose (GP) commodity resins. This paper tries to define what specialty PVC resins are, how they are produced, and their markets, applications, fabrication processes, and compounding as compared to those of GP resins. 相似文献
48.
Pierre-Claude Aïtcin Shondeep L. Sarkar M. Regourd D. Volant 《Cement and Concrete Research》1987,17(6):995-999
Cement hydration is a complex chemical process strongly influenced by the proportions of the various minerals present in the cement, admixtures, and the size of the cement particles. In this note, it is shows that naphthalene based superplasticizer, used at high dosage, does not affect the total heat of hydration but retards the hydration process of portland cement. This retardation, however, is most effective on the medium size fraction of the cement (4 – 30 μm in our case). The superplasticizer does not affect the hydration of the fine fraction (< 4 μm) to that extent due to its richer concentration of SO3 and alkalies. The coarse fraction of the cement (30 – 72 μm) does not participate (with or without superplasticizer) in the heat evolution process. 相似文献
49.
Blends of poly (vinyl chloride) (PVC) and acrylonitrile-butadiene styrene (ABS) terpolymer were prepared in different ratios by a melt blending technique. ABS containing three different levels of rubber content were used. A quantitative assessment of ABS in PVC/ABS blends has been shown by infrared studies. ABS content has been shown as the presence of the characteristic acrylonitrile peak. Differential scanning calorimetry (DSC) studies have been carried out to study the glass transition (Tg) behavior of the blends. Two Tg values corresponding to PVC and styrene-acrylonitrile (SAN) copolymer have been observed. Thermogravimetric analysis (TGA) reveals a significant improvement in thermal stability of these blends as compared to PVC. Mechanical properties show a significant increase in the impact strength which is related to rubber content of the ABS used. Morphological studies have been carried out by scanning electron microscopy which support the observation that an increase in rubber content results in greater ductility. 相似文献
50.
Anandrao R. Kulkarni Kumaresh S. Soppimath Tejraj M. Aminabhavi Ashok M. Dave 《应用聚合物科学杂志》2002,85(5):911-918
Novel polymeric sodium alginate (Na‐Alg) interpenetrating network (IPN) beads have been prepared by crosslinking Na‐Alg blend with gelatin (GE) or egg albumin (EA) using glutaraldehyde (GA) as the crosslinking agent. These beads were used for the controlled release of chlorpyrifos. The swelling experiments were performed in water at different temperatures, and these data were used to calculate the molecular mass (MC) between crosslinks as well as diffusion coefficients. Diffusion coefficients calculated from desorption data were lower by about two orders of magnitude than those calculated from sorption results. Higher values of MC were obtained for the gelatin‐based IPNs than the neat Na‐Alg and egg albumin‐based matrices. Size of the beads did not vary significantly either by the network or by increasing the exposure time to the crosslinking agent. The scanning electron microscopy (SEM) was used to understand the surface characteristics of the beads. Differential scanning calorimetry (DSC) indicated a molecular level dispersion of chlorpyrifos in the polymer matrix. The percentage entrapment efficiency showed a dependence on the type of network polymer as well as time of exposure to the crosslinking agent. The encapsulation efficiency decreased with an increase in time of exposure to the crosslinking agent. In vitro release experiments have been performed to follow the release kinetics of chlorpyrifos from the matrices. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 911–918, 2002 相似文献