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排序方式: 共有626条查询结果,搜索用时 15 毫秒
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Ahmet Sarı Mohammed Ouikhalfan Hassan Chehouani Gökhan Hekimoğlu Alper Bicer Amir Al-Ahmed Fahad A. Al-Sulaiman Vineet Veer Tyagi 《Polymer Engineering and Science》2020,60(5):909-916
In this work, polyethylene glycol (PEG) as a phase change material (PCM) was incorporated with palygorskite (Pal) clay to develop a novel form-stable composite PCM (F-SCPCM). The Pal/PEG(40 wt%) composite was defined as F-SCPCM and characterized using SEM/EDS, FT-IR, XRD, DSC, and TGA techniques. The DSC results revealed that the F-SCPCM has a melting temperature of 32.5°C and latent heat capacity of 64.3 J/g for thermal energy storage (TES) applications. Thermal cycling test showed that the F-SCPCM had good cycling thermal/chemical stability after 500 cycles. The TGA data proved that that both cycled and non-cycled F-SCPCMs had considerable high thermal durability. Consequently, the created F-SCPCM could be considered as an additive material for production of green construction components with TES capability. POLYM. ENG. SCI., 60:909–916, 2020. © 2020 Society of Plastics Engineers 相似文献
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Amreesh Chandra A. K. Tyagi V. Vijaykumar G. D. Mukherjee R. Boehler 《Journal of Electroceramics》2011,26(1-4):191-199
Pressure dependent studies on technologically important ferroelectric material Pb0.70Ca0.30TiO3 show the occurrence of a new hitherto unreported pressure dependent phase transition around 4 GPa. In the pressure range 4–14 GPa, the parent tetragonal (P4mm) phase of Pb0.70Ca0.30TiO3 transforms in to a monoclinic (Cm) phase before attaining its paraelectric cubic (Pm3m) phase around 15 GPa. High pressure Raman studies reveal the presence of a critical pressure above which the ferroelectric phase starts to reappear in the paraelectric phase. This critical pressure is found to be much lower than the critical pressure observed in pure PbTiO3. Possible reasons for this lowering of the critical pressure are presented. 相似文献
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Quaternary ammonium salts (otherwise known as “quats”) commonly form the foundation of formulations in the antimicrobial industry.
Many studies have been conducted on the biological activity of surfactants derived from fatty acids viz. lauric acid, myristic
acid, stearic acid and palmitic acid and palm fatty acid with polyamine, i.e. 1(2-hydroxyethylpiperazine). The present paper
investigates the synthesis and surface-active properties of esteramide quats derived from the esterification of the above-mentioned
fatty acids and 1(2-hydroxyethylpiperazine) followed by quaternization using dimethyl sulphate (DMS). These derivatives were
fully characterized by using Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance (NMR) spectroscopy, and
13C-NMR spectroscopy. In addition to the cationic content, surface tension, CMC (critical micelle concentration), fabric softening,
rewettability, emulsification and dispersing power were determined as their surface-active properties.
相似文献
Shilpi MishraEmail: |
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The design of pulse position modulated (PPM) space-time trellis codes (STTC) for ultra-wideband impulse radio (UWB-IR) multiple-input multiple-output (MIMO) communication systems over slow and fast fading multipath channels is considered. First, A probability of error analysis is carried out to derive upper bounds on pairwise symbol error probability at high and low signal-to-noise ratios (SNRs). From the upper bounds, A new distance notion is introduced and novel design criteria for optimal (in error rate performance) M-ary PPM STTC are deduced for UWB. An optimal binary-PPM STTC is designed for two transmit antennas. Finally, simulation results of the UWB-IR MIMO system, using the optimal STTC, confirm significant improvement in bit-error-rate performance over the uncoded UWB-IR single-input single-output system and also over previously proposed space-time coding scheme for UWB, at higher SNR. 相似文献
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R. Rajesh M. Hussain Z. H. Zaidi R. K. Tyagi Gaurav Singhal Mainuddin A. L. Dawar M. Endo 《Journal of Infrared, Millimeter and Terahertz Waves》2004,25(9):1361-1382
Chemical oxygen-iodine Laser (COIL) is one of the fast emerging high power laser source for near Infrared (λ=1.315μm) laser generation. The heart of the system is the singlet oxygen generator (SOG) which is a pumping source for this laser. A Jet type SOG with a novel approach was designed and fabricated. Singlet oxygen was taken out of the SOG at an angle of 40° thus avoiding the carry over of droplets, which is one of the major drawbacks of horizontal system. The preliminary results have been reported in our earlier publication. The present paper discusses the performance of this generator for various operational conditions viz. diluent's gas nitrogen / helium, basic hydrogen peroxide composition, generator pressure and gas velocity. Further, conditions for the stable operation from generator as well as chlorine injection point of view have been identified. 相似文献
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