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排序方式: 共有950条查询结果,搜索用时 15 毫秒
31.
Pei Sean Goh Kar Chun Wong Tuck Whye Wong Ahmad Fauzi Ismail 《Frontiers of Chemical Science and Engineering》2022,16(5):564
Polyamide thin film composite membranes have dominated current reverse osmosis market on account of their excellent separation performances compared to the integrally skinned counterparts. Despite their very promising separation performance, chlorine-induced degradation resulted from the susceptibility of polyamide toward chlorine attack has been regarded as the Achilles’s heel of polyamide thin film composite. The free chlorine species present during chlorine treatment can impair membrane performance through chlorination and depolymerization of the polyamide selective layer. From material point of view, a chemically stable membrane is crucial for the sustainable application of membrane separation process as it warrants a longer membrane lifespan and reduces the cost involved in membrane replacement. Various strategies, particularly those involved membrane material optimization and surface modifications, have been established to address this issue. This review discusses membrane degradation by free chlorine attack and its correlation with the surface chemistry of polyamide. The advancement in the development of chlorine resistant polyamide thin film composite membranes is reviewed based on the state-of-the-art surface modifications and tailoring approaches which include the in situ and post-fabrication membrane modifications using a broad range of functional materials. The challenges and future directions in this field are also highlighted. 相似文献
32.
Jena Biswajit Bhol Krutideepa Nanda Umakanta Tayal Shubham Routray Soumya Ranjan 《SILICON》2022,14(6):3005-3012
Silicon - This work represents a unique GAA MOSFET with metal work-function variations (WFVs) and ferroelectric material as dielectric. A random distribution of metal grain (TiN) with grain size... 相似文献
33.
Ayan Kar Ke-Bin Low Michael Oye Michael A Stroscio Mitra Dutta Alan Nicholls M Meyyappan 《Nanoscale research letters》2011,6(1):3-9
ZnO nanowire nucleation mechanism and initial stages of nanowire growth using the carbothermal reduction technique are studied
confirming the involvement of the catalyst at the tip in the growth process. Role of the Au catalyst is further confirmed
when the tapering observed in the nanowires can be explained by the change in the shape of the catalyst causing a variation
of the contact area at the liquid–solid interface of the nanowires. The rate of decrease in nanowire diameter with length
on the average is found to be 0.36 nm/s and this rate is larger near the base. Variation in the ZnO nanowire diameter with
length is further explained on the basis of the rate at which Zn atoms are supplied as well as the droplet stability at the
high flow rates and temperature. Further, saw-tooth faceting is noticed in tapered nanowires, and the formation is analyzed
crystallographically. 相似文献
34.
A method is presented for significantly reducing the interfacial contact resistance of single-walled carbon nanotube (SWCNT) interconnects test-structures. Conventional lithographic cleaning steps are insufficient for complete removal of lithographic residues in SWCNT networks, leading to large interfacial contact resistance. Using improved purification procedures and controlled developing time, the interfacial contact resistance between SWCNTs and contact electrodes of Ti/Au were found to reach values below 2% of the overall resistance in two-probe test-structures of SWCNTs, demonstrating the importance of cleaning lithographic residues from the surface of SWCNTs before the fabrication of metal electrodes. These low-resistance contacts are quite stable over a large temperature range, and represent a step towards the implementation of SWCNTs as future interconnects. 相似文献
35.
Chameswary Janardhanan Dhanesh Thomas Ganesanpotti Subodh Soumya Harshan Jacob Philip Mailadil T. Sebastian 《应用聚合物科学杂志》2012,124(4):3426-3433
Butyl rubber–strontium cerium titanate (BS) composites have been prepared by hot pressing. The tensile tests show that the BS composites are flexible. The dielectric properties of the composites have been investigated at 1 MHz and 5 GHz as a function of ceramic contents. The composite with volume fraction 0.43 of ceramic filler has a dielectric constant (εr) of 11.9 and dielectric loss (tan δ) 1.8 × 10?3 at 5 GHz. The measured values of εr are compared with the effective values calculated using different theoretical models. The thermal conductivity of the composites is found to increase with ceramic contents and reaches a value of 4.5 Wm?1 K?1 for maximum filler loading 0.43 volume fraction. The coefficient of thermal expansion of the composites decreases gradually with filler loading and reaches a minimum value of 30.2 ppm °C?1 at a volume fraction 0.43. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
36.
Positive temperature coefficient to resistivity characteristics of high density polyethylene (HDPE)/silver (Ag)‐coated glass bead (45 wt%) composites, without and with nanoclay, has been investigated with reference to HDPE/carbon black (CB) (10 wt%) composites. Plot of resistivity versus temperature of HDPE/CB (10 wt%) composites showed a sudden rise in resistivity (PTC trip) at ≈128°C, close to the melting temperature (Tm) of HDPE. However, for HDPE/Ag coated glass bead (45 wt%) composites, the PTC trip temperature (≈88°C) appeared well below the Tm of HDPE. Addition of 1 phr clay in the composites resulted in an increase in PTC trip temperature of HDPE/Ag‐coated glass bead (45 wt%) composites, whereas no significant effect of clay on PTC trip temperature was evident in HDPE/CB/clay composites. We proposed that the PTC trip temperature in HDPE/Ag‐coated glass bead composites was governed by the difference in coefficient of thermal expansion of HDPE and Ag‐coated glass beads. The room temperature resistivity and PTC trip temperature of HDPE/Ag‐coated glass bead (45 wt%) composites were found to be very stable on thermal cycling. Dynamic mechanical analyzer results showed higher storage modulus of HDPE/Ag‐coated glass bead (45 wt%) composites compared with the HDPE/CB (10 wt%) composites. Thermal stability of HDPE/Ag‐coated glass bead (45 wt%) composites was also improved compared with that of HDPE/CB (10 wt%) composites. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers 相似文献
37.
Soumya Ghosh Chowdhury Jagannath Chanda Sreedip Ghosh Koushik Banerjee Shib Shankar Banerjee Amit Das Prasenjit Ghosh Sanjay Kr. Bhattacharyya Rabindra Mukhopadhyay 《Polymer Engineering and Science》2020,60(8):1973-1983
Proficiency on underlying mechanism of rubber-metal adhesion has been increased significantly in the last few decades. Researchers have investigated the effect of various ingredients, such as hexamethoxymethyl melamine, resorcinol, cobalt stearate, and silica, on rubber-metal interface. The role of each ingredient on rubber-metal interfacial adhesion is still a subject of scrutiny. In this article, a typical belt skim compound of truck radial tire is selected and the effect of each adhesive ingredient on adhesion strength is explored. Out of these ingredients, the effect of cobalt stearate is found noteworthy. It has improved adhesion strength by 12% (without aging) and by 11% (humid-aged), respectively, over control compound. For detailed understanding of the effect of cobalt stearate on adhesion, scanning electron microscopy and energy dispersive spectroscopy are utilized to ascertain the rubber coverage and distribution of elements. X-ray photoelectron spectroscopy results helped us to understand the impact of CuXS layer depth on rubber-metal adhesion. The depth profile of the CuXS layer was found to be one of the dominant factors of rubber-metal adhesion retention. Thus, this study has made an attempt to find the impact of different adhesive ingredients on the formation of CuXS layer depth at rubber-metal interface and establish a correlation with adhesion strength simultaneously. 相似文献
38.
39.
Electrical,mechanical, and thermal properties of exfoliated graphite/phenolic resin composite bipolar plate for polymer electrolyte membrane fuel cell 下载免费PDF全文
Exfoliated graphite (EG) was synthesized from natural flake graphite by acid treatment followed by microwave irradiation. A maximum expanded volume of 560 mL/g was achieved for this exfoliation of graphite. EG/phenolic resin composite bipolar plates for polymer electrolyte membrane fuel cell were fabricated with a high loading of EG by compression molding. The composites possess low density, high electrical conductivity, high thermal stability, and high compressive strength. The composite bipolar plates were also characterized by X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, and so on. The composite prepared with 50 wt% of EG has shown the desired properties for bipolar plate as per the US Department of Energy (DOE‐2015) targets. As a result, the EG–resin composites can be used as bipolar plates for polymer electrolyte membrane fuel cell applications. POLYM. ENG. SCI., 55:917–923, 2015. © 2014 Society of Plastics Engineers 相似文献
40.
Chou Yong Tan Ramesh Singh Yee Ching Teh Yoke Meng Tan Boon Kar Yap 《International Journal of Applied Ceramic Technology》2015,12(2):437-442
In this work, the sinterability of forsterite powder synthesized via solid‐state reaction was investigated. X‐ray diffraction (XRD) analyses indicate that the synthesized powder possessed peaks that correspond to stoichiometric forsterite. Scanning electron micrographs revealed that the powders were formed agglomerates, which were made up of loosely packed fine particles. Subsequently, the forsterite powders were cold isostatically pressed into a disk shape under 200 MPa and sintered in air at temperature ranging from 1200°C to 1500°C (interval of 50°C) with ramp rate of 10°C/min and dwelling time of 2 h. The sinterability of each sintered samples was examined in terms of phase stability, relative density, Vickers hardness, fracture toughness, and microstructural examination. XRD examination on all the sintered samples exhibited pure forsterite, in which the generated peaks were found to be in a good agreement with JCPDS card no. 34‐0189. The densification of forsterite progressed to reach a maximum relative density of ~91% at 1500°C. This study also revealed that high‐strength forsterite ceramic can be synthesized via solid‐state reaction as forsterite attained favorable mechanical properties, having fracture toughness of 4.88 MPam1/2 and hardness of 7.11 GPa at 1400°C. 相似文献