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201.
The wide applicability of poly(vinyl chloride) (PVC), a tough thermoplastic resin, is due to a combination of moderate cost with the following characteristics [1]: (i) good general properties as a plastic material: (ii) great variation in properties, e.g., increase in heat distortion temperature, resistance to hot melt flow, improvement in mechanical, electrical properties, and processability of unplasticized PVC through external plasticization, block and graft copolymerization (internal plasticization), and chemical modification, e.g., chlorination, Friedel-Crafts, and cross-linking reactions: and (iii) processing versatility including injection molding, extrusion, blow molding, calendering, and lamination to produce many products of potential uses. 相似文献
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Optics has an important role in logic implementation and computation is established in two and half decades by many researchers. Recently frequency encoding technique is established. This technique does not suffer from intensity dependent loss problems like other schemes. Amorphous dielectric thin films with reflecting edges can also be used for logic realization and has very fast response speed. It also does not use any semiconductor device and simple to construct. In this communication the authors have proposed all optical CNOT gate using frequency encoded difference frequency generation exploiting nonlinear response of some material and implementation of binary adders by CNOT gate and dielectric thin film AND gate. 相似文献
206.
Medha Rele B. S. Patro S. Adhikari G. P. Kalena S. Chattopadhyay T. Mukherjee 《Journal of Chemical Sciences》2002,114(6):739-747
The free radical scavenging properties and possible antioxidant activity of 1,3-diphenylpropane-1,3-dione (1) are reported.
Pulse radiolysis technique was employed to study the one-electron oxidation of 1 with various radicals viz. CCl3O2
•, N3
• and•OH in homogeneous aqueous solution. All these radicals reacted with 1 under ambient conditions at almost diffusion controlled
rates producing transient species with an absorption maximum around 420 nm that decayed at first order rates. The transient
absorption peak was shifted in the case of CCl3OO• radical reaction with 1 due to change in the polarity of the medium. Formation of a stable product with a broad absorption
band starting from 400 nm and cut off at 230 nm was observed in the oxidation of 1 with•OH and•N3 radicals. In a biological system also, 1 showed significant inhibitory activity against Fe2+-mediatedlipidperoxidation. Based on these observations, a suitable mechanism for the oxidation of 1 has been proposed. 相似文献
207.
208.
It is shown that SU(2)×U(1) can be broken at the tree level, without the occurrence of global potential minima that break
U(1)e.m., in supergravity models that are more general than those proposed by Nilles, Srednicki and Wyler. The study comprises an
analysis of models with a general soft supersymmetry-breaking structure as well as those of the Hall-Lykken-Weinberg type. 相似文献
209.
G. S. Mukherjee 《Journal of Thermal Analysis and Calorimetry》2009,96(1):21-25
There is ample scope for modification of polyvinyl alcohol (PVA) to derive diverse range of properties because of the presence
of hydroxyl group in its chain. In the present work, PVA has been modified to carboxymethylated polyvinyl alcohol (CPVA) —
a carboxy-functionalized membrane material. Generally the cohesive energy density has incremental influence on the melting
point and mechanical strength of a material but in this case of CPVA even though theoretical cohesive energy density of CPVA
is lower than that of PVA but paradoxically its mechanical strength was found to be higher than that of PVA (∼202 vis-à-vis
207°C and ∼174 vis-à-vis ∼58 MPa, respectively). Calorimetric evaluation along with the energy balance concept have provided
meaningful information to justify such paradoxical feature as a result of the dominating role of intermolecular hydrogen bonding
in CPVA to compensate for its relatively lower cohesive energy density typically 0.05 J m−3/2.
Thermal analysis has been made to examine the role of PVA and its carboxymethylated derivative (CPVA) towards moisture. It
was observed that PVA membrane surface became sticky on exposure to water at 30°C for a period of 30 min, whereas under the
same condition CPVA counterpart remained practically unaffected. 相似文献
210.
A. Chatterjee A. Sarkar Sourav Bhattacharya P. Mukherjee N. Gayathri P. Barat 《Physics letters. A》2008,372(22):4016-4020
Tensile tests were carried out by deforming polycrystalline samples of substitutional Al–2.5%Mg alloy at room temperature for a range of strain rates. The Portevin–Le Chatelier (PLC) effect was observed throughout the strain rate regime. The deformation bands in this region are found to be of type A in nature. From the analysis of the experimental stress time series data we could infer that the dynamics of type A dislocation band propagation is a Markov process. 相似文献