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81.
82.
Chia‐Che Chang Sin‐Ren Li Hung‐Lung Chou Yi‐Cheng Lee Shivaraj Patil Ying‐Sheng Lin Chun‐Chih Chang Yuan Jay Chang Di‐Yan Wang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(49)
The generation of ammonia, hydrogen production, and nitrogen purification are considered as energy intensive processes accompanied with large amounts of CO2 emission. An electrochemical method assisted by photoenergy is widely utilized for the chemical energy conversion. In this work, earth‐abundant iron pyrite (FeS2) nanocrystals grown on carbon fiber paper (FeS2/CFP) are found to be an electrochemical and photoactive catalyst for nitrogen reduction reaction under ambient temperature and pressure. The electrochemical results reveal that FeS2/CFP achieves a high Faradaic efficiency (FE) of ≈14.14% and NH3 yield rate of ≈0.096 µg min?1 at ?0.6 V versus RHE electrode in 0.25 m LiClO4. During the electrochemical catalytic reaction, the crystal structure of FeS2/CFP remains in the cubic pyrite phase, as analyzed by in situ X‐ray diffraction measurements. With near‐infrared laser irradiation (808 nm), the NH3 yield rate of the FeS2/CFP catalyst can be slightly improved to 0.1 µg min?1 with high FE of 14.57%. Furthermore, density functional theory calculations demonstrate that the N2 molecule has strong chemical adsorption energy on the iron atom of FeS2. Overall, iron pyrite‐based materials have proven to be a potential electrocatalyst with photoactive behavior for ammonia production in practical applications. 相似文献
83.
84.
Using channel state dependent packet scheduling to improve TCPthroughput over wireless LANs 总被引:1,自引:0,他引:1
Pravin Bhagwat Partha Bhattacharya Arvind Krishna Satish K. Tripathi 《Wireless Networks》1997,3(1):91-102
In recent years, a variety of mobile computers equipped with wireless communication devices have become popular. These computers
use applications and protocols, originally developed for wired desktop hosts, to communicate over wireless channels. Unlike
wired networks, packets transmitted on wireless channels are often subject to burst errors which cause back to back packet
losses. In this paper we study the effect of burst packet errors and error recovery mechanisms employed in wireless MAC protocols
on the performance of transport protocols such as TCP. Most wireless LAN link layer protocols recover from packet losses by
retransmitting lost segments. When the wireless channel is in a burst error state, most retransmission attempts fail, thereby
causing poor utilization of the wireless channel. Furthermore, in the event of multiple sessions sharing a wireless link,
FIFO packet scheduling can cause the HOL blocking effect, resulting in unfair sharing of the bandwidth. This observation leads
to a new class of packet dispatching methods which explicitly take wireless channel characteristics into consideration in
making packet dispatching decisions. We compare a variety of channel state dependent packet (CSDP) scheduling methods with
a view towards enhancing the performance of transport layer sessions. Our results indicate that by employing a CSDP scheduler
at the wireless LAN device driver level, significant improvement in channel utilization can be achieved in typical wireless
LAN configurations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
85.
H. T. Lokhande A. D. Pawar S. R. Shukla P. K. Chidambareswaran N. B. Patil 《应用聚合物科学杂志》1983,28(7):2235-2245
Kinetic studies of swelling of cotton cellulose with 75% (w/w) EDA solution have been carried out. Three rates of the reaction were observed in the temperature range 10–35°C: first, the very fast rate (k1) lasting for about 10 s; second, the extremely slow rate (k2) lasting for 30–50 s; and third, once again a fast rate (k3), k1 being faster than k3. k1 was attributed to the swelling action of EDA–monohydrate in amorphous regions of cellulose; k2 was assigned to the penetration of swelling species into crystallities accompanied by breakage of H bonds in these regions; and k3 was assigned to the opening up of the crystallites. Activation energy values confirmed this trend. At higher temperatures (35–55°C), the middle rate k2 merged with k3, giving only two rates, k1 and k2+3, as the higher temperatures brought about simultaneous diffusion of swelling agent into, and decrystallization of, the crystalline portions of cellulose. EDA solution of 65% (w/w) concentration gave only two rates: the initial fast rate assigned to the swelling of the amorphous portion, followed by a slow one, operating in mesomorphous regions of cellulose, without any appreciable decrystallization. This was atributed to the important fact, viz., the absence of EDA–monohydrates in the solution. 相似文献
86.
Zahida Begum A. Poonguzhali Ranita Basu C. Sudha H. Shaikh R.V. Subba Rao Awanikumar Patil R.K. Dayal 《Corrosion Science》2011,53(4):1424-1432
Corrosion fatigue behaviour of four types of austenitic stainless steels were investigated in boiling 45% magnesium chloride solution at a stress ratio of 0.25 and a frequency of 0.1 Hz. Type 316LN stainless steel possessed the best resistance and type 304 stainless steel had the lowest resistance to corrosion fatigue. XPS studies on the fracture surface indicated that the presence of nitrogen as ion in the surface film of type 316LN stainless steel gave it the highest resistance to corrosion fatigue. Fractographic examination showed wholly transgranular cracking in all cases. 相似文献
87.
The effect on the interfacial tension of the water toluene system has been studied at 25 °C in the presence of four phase-transfer catalysts i.e. tricaprylmethyl ammonium chloride, hexadecyltrimethyl ammonium chloride, hex-adecytrimethyl ammonium bromide and hexadecyltributyl phosphonium bromide. The interfacial tension of aqueous phenol/resorcinol-toluene in the presence and absence of tricaprylmethyl ammonium chloride has also been reported. Attempt has been made to elucidate the change in volumetric rate of extraction with different catalysts for two phase reactions, on the basis of interfacial tension. 相似文献
88.
Solid‐state NMR study of spin finish of thermally treated PAN and PAN/CNT precursor fibers 下载免费PDF全文
Sushanta Ghoshal Yaodong Liu Prabhakar Gulgunje Kishor Gupta Han Gi Chae Johannes Leisen Satish Kumar 《应用聚合物科学杂志》2014,131(17)
Dry‐jet wet‐spun polyacrylonitrile (PAN) and PAN/carbon nanotubes (CNTs) precursor fibers coated by spin finishes were characterized using the solid‐state 1H nuclear magnetic resonance technique. Series of fiber samples were prepared upon thermal treatment at different temperatures (room temperature to 180°C). Using the Hahn echo sequence, relatively mobile components were identified and the effect of the heat treatment on those components was studied. It was observed that the mobile components are mainly the spin finishes. Heat treatment caused loss of one of the spin finishes (Type B) to a great extent (~80%), whereas the other two spin finishes (Type A and Type C) were more stable. Additional information regarding the change in molecular mobility due to heat treatment was obtained by the spin‐lattice relaxation time ( T1 ) analysis. It was found that the presence of CNT affects the T1 relaxation time of the polymer in the composite fiber, however, that of relatively mobile components remains unaffected. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40734. 相似文献
89.
Harishchandra D. Jirimali Bhushan C. Chaudhari Jitendra C. Khanderay Sachin A. Joshi Vijay Singh Amardip M. Patil 《Polymer-Plastics Technology and Engineering》2018,57(8):804-811
Waste eggshells were utilized to make calcium oxide (E-CaO) and hydroxyapatite (E-HAP). E-CaO obtained by heat treatment to eggshells was utilized for the synthesis of E-HAP. Melt compounding of E-CaO/E-HAP was performed with linear low-density polyethylene (LLDPE) on a Brabender Plastograph and ground the obtained formulation for injection molding. Addition of E-CaO/E-HAP in the LLDPE significantly enhanced the flame retardant ability and thermal stability of resultant composites. In the comparative study, E-HAP nanopowder-containing polymer composite showed increment in thermal and mechanical properties than the composite prepared using E-CaO. 相似文献
90.
The simultaneous addition of styrene maleic anhydride copolymer and multiwall carbon nanotubes during melt‐mixing on the morphology of binary blends of polyamide6 and acrylonitrile butadiene styrene copolymer 下载免费PDF全文
B.F. Jogi Arup R. Bhattacharyya Amrita V. Poyekar Petra Pötschke George P. Simon Satish Kumar 《Polymer Engineering and Science》2015,55(2):457-465
The effect of simultaneous addition of multiwall carbon nanotubes (MWNTs) and a reactive compatibilizer (styrene maleic anhydride copolymer, SMA) during melt‐mixing on the phase morphology of 80/20 (wt/wt) PA6/ABS blend has been investigated. Morphological analysis through scanning and transmission electron microscopic analysis revealed finer morphology of the blends in presence of SMA + MWNTs. Fourier transform infrared spectroscopic analysis indicated the formation of imide bonds during melt‐mixing. Non‐isothermal crystallization studies exhibited the presence of a majority faction of MWNTs in the PA6 phase of 80/20 (wt/wt) PA6/ABS blend in presence of SMA + MWNTs. Rheological analysis, dynamic mechanical thermal analysis, and thermogravimetric analysis have demonstrated the compatibilization action of simultaneous addition of a reactive compatibilizer (SMA copolymer) and MWNTs in PA6/ABS blends. An attempt has been made to investigate the role of simultaneous addition of SMA copolymer and MWNTs on the morphology of 80/20 (wt/wt) PA6/ABS blend through various characterization techniques. POLYM. ENG. SCI., 55:457–465, 2015. © 2014 Society of Plastics Engineers 相似文献