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排序方式: 共有1406条查询结果,搜索用时 437 毫秒
1.
Wireless Personal Communications - Recently, the theory of effective rate has attracted much attention, since it can take the delay aspect into account when performing channel capacity analysis. In... 相似文献
2.
3.
Jain Amita Yadav Sudesh Vij Sonakshi Kumar Yogesh Tayal Devendra Kumar 《Wireless Personal Communications》2020,110(3):1303-1321
Wireless Personal Communications - Traffic network is basically a “network of networks” consisting of mainly two types of networks: road network and a travel network. Due to drastic... 相似文献
4.
Multimedia Tools and Applications - In the way of communication, facial expression act as non-verbal communication and play an important role in social interaction by providing some contextual... 相似文献
5.
Higher order elastic constants have been calculated in ZnS at 300 K and 500 K following the interaction potential model. Ultrasonic attenuation, velocity and other related parameters have been calculated using the higher order elastic constants for the different size of the material at 500 K. The size dependency of the ultrasonic properties is discussed in correlation with elastic, thermal and electrical properties. It has been found that the thermal conductivity is the main contributor to the behaviour of the ultrasonic attenuation as a function of the size and the responsible cause of attenuation is phonon-phonon interaction. The semiconducting nature of ZnS film has been achieved with the study of size variation of thermal relaxation time and ultrasonic attenuation. 相似文献
6.
N. K. Acharya P. K. Yadav S. Wate Y. K. Vijay F. Singh D. Kavasthi 《Bulletin of Materials Science》2004,27(5):417-420
Ion irradiation of Si8+ ion beam of 100 MeV was scattered by a gold foil on a Mylar membrane of 25 Μm thickness in the form of film roll (width,
12.5 cm and length, 400 cm) at the Nuclear Science Centre, New Delhi. The characterization of etched nuclear tracks was carried
out by gas permeation measurements. The samples cut from the film roll of required size for permeability measurements were
etched in a controlled manner in a constant temperature bath of 6N NaOH solution. The opening of the conical etched tracks
was characterized by hydrogen gas permeation. 相似文献
7.
An asymmetric line-axis compound parabolic concentrating single basin solar still of concentration 1.15, exit aperture 0.24 metres and length 0.48 metres, 30° inclination and 60° half acceptance angle has been designed fabricated and tested. 相似文献
8.
Md. A. Mohiddon R. Kumar P. Goel K. L.Yadav 《Dielectrics and Electrical Insulation, IEEE Transactions on》2007,14(1):204-211
The aim of this study is to determine the effect of Nb5+ doping on PZT (65/35) based bulk materials in their structure, micro structure and electrical properties. The Nb content was chosen 0-9 mole%. These materials were prepared by conventional mixed oxide method. X ray diffraction studies suggest the compound to be of rhombohedral perovskite phase. Excess addition of Nb result in pyrochlore and fluorite phase develops in PZT (65/35) sample. Detailed studies of dielectric constant as a function of temperature (40degC to 500degC) and frequency (100 Hz to 1 MHz) suggest that the compounds undergo diffuse type of phase transition. Maximum dielectric constant and resistivity were found to be strongly dependent on doping and measuring frequencies. Using complex impedance analysis micro structural parameters such as bulk and grain boundary resistance, bulk charge carrier concentration and relaxation time were determined 相似文献
9.
Sangeeta A Godbole Thirumalai G Krishna Chittaranjan R Bhatia 《Journal of the science of food and agriculture》1994,64(3):331-335
Cajanus trypsin inhibitor (CTI) and Cajanus trypsin-chymotrypsin inhibitor (CTCI) previously purified from cv TAT-10 were further characterised. The modification of the inhibitors revealed the presence of lysine at the trypsin reactive site in both CTI and CTCI. Modification of tyrosine at the reactive site of CTCI did not abolish chymotrypsin inhibition suggesting the presence of leucine or phenylalanine as reported in other chymotrypsin inhibitors. CTCI did not contain tryptophan. Dissociation constants for the inhibitors with bovine trypsin were in the region of 0.69 nmol (CTCI) and 0.029 nmol (CTI). Although the protease inhibitors lost their inhibitory activity on exposure to 2-mercaptoethanol they remained attached to the enzyme. The inhibitors were not very effective against the protease from Helicoverpa armigera which is a serious field pest of Cajanus. Dissociation constants for the inhibitors with the larval enzyme were in the region of 100 nmol. 相似文献
10.
2',4'-Dihydroxyacetophenone, also known as resoacetophenone, is a commercially important intermediate which is generally
prepared by the acylation of resorcinol with acetic acid in the presence of a molar excess of zinc chloride, which leads to
waste disposal problems. The most frequently used acylating agents such as acetic anhydride and acetyl chloride have several
disadvantages and need to be replaced by cheap and benign agents. In this connection, acetic acid is a better choice but with
a non-polluting and reusable catalyst. The synthesis of 2',4'-dihydroxyacetophenone from resorcinol and acetic acid was carried
out in the presence of a variety of solid acid catalysts such as montmorillonite clay (K-10), dodecatungstophosphoric acid
(DTP) supported on K-10, sulfated zirconia and ion exchange resins. Amongst these catalysts, Amberlyst-36, an ion exchange
resin, was found to be the most effective. The effects of various parameters on the rate of reaction and selectivity were
investigated to establish the intrinsic kinetics of the reaction. It was possible to deduce the adsorption equilibrium constant
and rate constant simultaneously for the reaction including the corresponding energies of activation. The catalyst is reusable.
The process is in consonance with the principles of green chemistry.
Electronic Publication 相似文献