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Synthesis of Nano-sized Yttria via a Sol-Gel Process Based on Hydrated Yttrium Nitrate and Ethylene Glycol and Its Catalytic Performance for Thermal Decomposition of NH_4ClO_4 被引量:11
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作者 陈伟凡 李凤生 +1 位作者 刘磊力 李永绣 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第5期543-548,共6页
Nano-sized yttria particles were synthesized via a non-aqueous sol-gel process based on hydrated yttrium nitrate and ethylene glycol. The effects of the molar ratio of ethylene glycol to yttrium ion and calcination te... Nano-sized yttria particles were synthesized via a non-aqueous sol-gel process based on hydrated yttrium nitrate and ethylene glycol. The effects of the molar ratio of ethylene glycol to yttrium ion and calcination temperature on crystallite size of the products were studied. The catalytic performance of the as-prepared yttria for the ammonium perchlorate (AP) decomposition was investigated by differential scanning calorimetry (DSC). The results indicate that the nano-sized cubic yttria particles with less than 20 nm in average crystallite size can be obtained after 2 h reflux at 70℃, dried at 90 ℃, forming xerogel, and followed by annealing of xerogel for 2 h, and that the addition of the nano-sized yttria to AP incorporates two small exothermic peaks of AP in the temperature ranges of 310 - 350 ℃ and 400 - 470 ℃ into a strong exothermic peak of AP and increases the apparent decomposition heat from 515 to over 1110 J·g^- 1. It is also clear that the temperature of AP decomposition exothermic peak decreases and the apparent decomposition heat of AP increases with the increase of the amount of nano-sized yttria. The fact that the addition of the 5 % nano-sized yttria to AP decreases the temperature of AP exothermic peak to 337.7℃ by reduction of 114.6℃ and increases the apparent decomposition heat from 515 to 1240 J·g^-1, reveals that nano-sized yttria shows strong catalytic property for AP thermal decomposition. 展开更多
关键词 nano-sized yttria ethylene glycol sol-gel ammonium perchlorate thermal decomposition catalytic property rare earths
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NiMo/Al_2O_3 catalyst containing nano-sized zeolite Y for deep hydrodesulfurization and hydrodenitrogenation of diesel 被引量:8
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作者 Hailiang Yin Tongna Zhou Yunqi Liu Yongming Chai Chenguang Liu 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2011年第4期441-448,共8页
Two mixed-matrix NiMo/Al2O3 catalysts containing nano-and micro-sized zeolite Y have been prepared to explore the size effect of zeolite Y particle on the hydrodesulfurization(HDS)and hydrodenitrogenation(HDN)acti... Two mixed-matrix NiMo/Al2O3 catalysts containing nano-and micro-sized zeolite Y have been prepared to explore the size effect of zeolite Y particle on the hydrodesulfurization(HDS)and hydrodenitrogenation(HDN)activities of fluid catalytic cracking(FCC)diesel.They were characterized by SEM,BET,XRD,H2-TPR,NH3-TPD and HRTEM.The results show that the catalyst containing nano-sized zeolite Y possesses larger average pore diameter,higher pore volume,weaker and lesser acid sites,more easily reducible metal phases,shorter MoS2 slabs and more slab layers than the catalyst containing micro-sized zeolite Y.The catalysts were also evaluated with a high-pressure fixed-bed reactor using real FCC diesel as feed.The results display that the catalyst containing nano-sized zeolite Y bears higher HDS and HDN activities and exhibits higher relative rate constant for the removal of total sulfur or nitrogen than the one containing micro-sized zeolite. 展开更多
关键词 zeolite Y nano-sized zeolite micro-sized zeolite HYDRODESULFURIZATION HYDRODENITROGENATION DIESEL
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Synthesis and Characterization of Nano-sized Boron Powder Prepared by Plasma Torch 被引量:5
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作者 黄志军 吴青友 +3 位作者 李祥 尚书勇 戴晓雁 印永祥 《Plasma Science and Technology》 SCIE EI CAS CSCD 2010年第5期577-580,共4页
Hydrogen thermal plasma jet was employed to prepare nano-sized boron powder with hydrogen reduction of BCI3. The maximum yield of nano-sized boron powders was about 50% with the operational conditions of H2/BCl3 of 4.... Hydrogen thermal plasma jet was employed to prepare nano-sized boron powder with hydrogen reduction of BCI3. The maximum yield of nano-sized boron powders was about 50% with the operational conditions of H2/BCl3 of 4.5:1, total feed of 4.9 m3/h, and plasma power of 25 kW. The samples were analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and inductively coupled plasma - mass spectrometry (ICP-MS), inductively coupled plasma - atomic emission spectrometry (ICP-AES), inductive combustion infrared absorption (ICIA) and infrared thermal conductivity of oxygen and nitrogen analyzer (ITCA). The results show that the boron powders have different crystal structures with higher dispersion and purity. The average diameter is about 50 nm, and the purity is 90.29% or so. This new technology can use simple process to produce high quality boron powders, and is feasible for industrial production. 展开更多
关键词 nano-sized boron powder thermal plasma ultra-fine powder
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Kinetics and Mechanism of Decomposition of Nano-sized Calcium Carbonate under Non-isothermal Condition 被引量:7
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作者 刘润静 陈建峰 +2 位作者 郭奋 吉米 沈志刚 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第3期302-306,共5页
Experiments on thermal decomposition of nano-sized calcium carbonate were carried out in a thermo-gravimetric analyzer under non-isothermal condition of different heating rates (5 to 20K·min-1). The Coats and Red... Experiments on thermal decomposition of nano-sized calcium carbonate were carried out in a thermo-gravimetric analyzer under non-isothermal condition of different heating rates (5 to 20K·min-1). The Coats and Redfern's equation was used to determine the apparent activation energy and the pre-exponential factors. The mechanism of thermal decomposition was evaluated using the master plots, Coats and Redfern's equation and the kinetic compensation law. It was found that the thermal decomposition property of nano-sized calcium carbonate was different from that of bulk calcite. Nano-sized calcium carbonate began to decompose at 640℃, which was 180℃lower than the reported value for calcite. The experimental results of kinetics were compatible with the mechanism of one-dimensional phase boundary movement. The apparent activation energy of nano-sized calcium carbonate was estimated to be 151kJ·mol-1 while the literature value for normal calcite was approximately 200kJ·mol-1. The order of magnitude of pre-exponential factors was estimated to be 10~9 s-1. 展开更多
关键词 nano-sized calcium carbonate non-isothermal decomposition kinetic mechanism
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Corrosion resistance of waterborne epoxy coating pigmented by nano-sized aluminium powder on steel 被引量:5
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作者 LIU Jian-hua ZHAN Zhong-wei +1 位作者 LI Song-mei YU Mei 《Journal of Central South University》 SCIE EI CAS 2012年第1期46-54,共9页
A novel kind of waterborne epoxy coating pigmented by nano-sized aluminium powders on high strength steel was formulated. Several coatings with different pigment volume content (PVC) were prepared. The coating morphol... A novel kind of waterborne epoxy coating pigmented by nano-sized aluminium powders on high strength steel was formulated. Several coatings with different pigment volume content (PVC) were prepared. The coating morphology was observed using scanning electron microscopy (SEM), and the electrochemical properties were investigated by electrochemical impedance spectroscopy (EIS). Immersion test and neutral salt spray test were also conducted to investigate the corrosion resistance of the coating. It is demonstrated that the critical pigment volume content (CPVC) value is between 30% and 40%. The coating with PVC of 30% exhibits good corrosion resistance in 3.5% (mass fraction) NaCl solution. 展开更多
关键词 nano-sized aluminium powder waterbome epoxy coating corrosion resistance pigment volume content
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Effects of nano-sized aluminum on detonation characteristics and metal acceleration for RDX-based aluminized explosive 被引量:5
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作者 Dan-yang Liu Pin Zhao +2 位作者 Serene Hay-Yee Chan Huey Hoon Hng Lang Chen 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第2期327-337,共11页
Nano-sized aluminum(Nano-Al)powders hold promise in enhancing the total energy of explosives and the metal acceleration ability at the same time.However,the near-detonation zone effects of reaction between Nano-Al wit... Nano-sized aluminum(Nano-Al)powders hold promise in enhancing the total energy of explosives and the metal acceleration ability at the same time.However,the near-detonation zone effects of reaction between Nano-Al with detonation products remain unclear.In this study,the overall reaction process of 170 nm Al with RDX explosive and its effect on detonation characteristics,detonation reaction zone,and the metal acceleration ability were comprehensively investigated through a variety of experiments such as the detonation velocity test,detonation pressure test,explosive/window interface velocity test and confined plate push test using high-resolution laser interferometry.Lithium fluoride(LiF),which has an inert behavior during the explosion,was used as a control to compare the contribution of the reaction of aluminum.A thermochemical approach that took into account the reactivity of aluminum and ensuing detonation products was adopted to calculate the additional energy release by afterburn.Combining the numerical simulations based on the calculated afterburn energy and experimental results,the parameters in the detonation equation of state describing the Nano-Al reaction characteristics were calibrated.This study found that when the 170 nm Al content is from 0%to 15%,every 5%increase of aluminum resulted in about a 1.3%decrease in detonation velocity.Manganin pressure gauge measurement showed no significant enhancement in detonation pressure.The detonation reaction time and reaction zone length of RDX/Al/wax/80/15/5 explosive is 64 ns and 0.47 mm,which is respectively 14%and 8%higher than that of RDX/wax/95/5 explosive(57 ns and 0.39 mm).Explosive/window interface velocity curves show that 170 nm Al mainly reacted with the RDX detonation products after the detonation front.For the recording time of about 10 ms throughout the plate push test duration,the maximum plate velocity and plate acceleration time accelerated by RDX/Al/wax/80/15/5 explosive is 12%and 2.9 ms higher than that of RDX/LiF/wax/80/15/5,respectively,indicating that the aluminum reaction energy significantly increased the metal acceleration time and ability of the explosive.Numerical simulations with JWLM explosive equation of state show that when the detonation products expanded to 2 times the initial volume,over 80%of the aluminum had reacted,implying very high reactivity.These results are significant in attaining a clear understanding of the reaction mechanism of Nano-Al in the development of aluminized explosives. 展开更多
关键词 nano-sized aluminum Detonation reaction zone Explosive metal acceleration Thermodynamic equilibrium calculation Laser interferometry
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Effect of deep cryogenic treatment on the formation of nano-sized carbides and the wear behavior of D2 tool steel 被引量:3
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作者 Kamran Amini Amin Akhbarizadeh Sirus Javadpour 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2012年第9期795-799,共5页
The effect of deep cryogenic treatment on the microstructure, hardness, and wear behavior of D2 tool steel was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffracti... The effect of deep cryogenic treatment on the microstructure, hardness, and wear behavior of D2 tool steel was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), hardness test, pin-on-disk wear test, and the reciprocating pin-on-fiat wear test. The results show that deep cryogenic treatment eliminates retained austenite, makes a better carbide distribution, and increases the carbide content. Furthermore, some new nano-sized carbides form during the deep cryogenic treatment, thereby increasing the hardness and improving the wear behavior of the samples. 展开更多
关键词 cryogenic treatment tool steel nano-sized carbides wear resistance HARDNESS AUSTENITE
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Deformation behavior of explosive detonation in electroformed nickel liner of shaped charge with nano-sized grains 被引量:3
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作者 杨峰 李春华 +2 位作者 成生伟 王雷 田文怀 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第8期1397-1402,共6页
Nickel liner of shaped charge with nano-sized grains was prepared by electroforming technique and the ultra-highstrain-rate deformation was performed by explosive detonation.The as-electroformed and post-deformed micr... Nickel liner of shaped charge with nano-sized grains was prepared by electroforming technique and the ultra-highstrain-rate deformation was performed by explosive detonation.The as-electroformed and post-deformed microstructures of electroformed nickel liner of shaped charge were observed by optical metallography(OM),scanning electron microscopy(SEM) and transmission electron microscopy(TEM) and the orientation distribution of the grains was analyzed by electron backscattering pattern(EBSP) technique.Both melting phenomenon in the jet fragment and recovery and recrystallization in the slug after ultra-high-strain-rate deformation were observed.The research evidence shows that dynamic recovery and recrystallization play an important role in ultra-high-strain-rate deformation for electroformed nickel liner of shaped charge with nano-sized grain. 展开更多
关键词 nano-sized electroformed nickel ultra-high-strain-rate deformation ELECTROFORMATION MICROTEXTURE dynamic recovery and recrystallization DETONATION
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Comparative study of the explosion pressure characteristics of micro- and nano-sized coal dust and methane–coal dust mixtures in a pipe 被引量:5
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作者 Bo Tan Huilin Liu +1 位作者 Bin Xu Tian Wang 《International Journal of Coal Science & Technology》 EI 2020年第1期68-78,共11页
Coal dust explosion accidents often cause substantial property damage and casualties and frequently involve nano-sized coal dust.In order to study the impact of nano-sized coal on coal dust and methane–coal dust expl... Coal dust explosion accidents often cause substantial property damage and casualties and frequently involve nano-sized coal dust.In order to study the impact of nano-sized coal on coal dust and methane–coal dust explosions,a pipe test apparatus was used to analyze the explosion pressure characteristics of five types of micro-nano particle dusts(800 nm,1200 nm,45μm,60μm,and 75μm)at five concentrations(100 g/m3,250 g/m3,500 g/m3,750 g/m3,and 1000 g/m3).The explosion pressure characteristics were closely related to the coal dust particle size and concentration.The maximum explosion pressure,maximum rate of pressure rise,and deflagration index for nano-sized coal dust were larger than for its micro-sized counterpart,indicating that a nano-sized coal dust explosion is more dangerous.The highest deflagration index Kst for coal dust was 13.97 MPa/(m·s),indicating weak explosibility.When 7%methane was added to the air,the maximum deflagration index Kst for methane–coal dust was 42.62 MPa/(m·s),indicating very strong explosibility.This indicates that adding methane to the coal dust mixture substantially increased the hazard grade. 展开更多
关键词 A pipe test apparatus nano-sized Coal dust explosion Methane/coal dust explosion Pressure characteristics
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Synthesis of Neodymium-Doped Yttrium Aluminum Garnet (Nd∶YAG) Nano-Sized Powders by Low Temperature Combustion 被引量:8
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作者 张华山 苏春辉 +1 位作者 韩辉 侯朝霞 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第3期304-308,共5页
The homogeneously dispersed, less agglomerated (Nd0.01Y0.99)3Al5O12 nano-sized powders were synthesized by the low temperature combustion (LCS), using Nd2O3, Y2O3, Al(NO3)3·9H2O, ammonia water and citric acid as ... The homogeneously dispersed, less agglomerated (Nd0.01Y0.99)3Al5O12 nano-sized powders were synthesized by the low temperature combustion (LCS), using Nd2O3, Y2O3, Al(NO3)3·9H2O, ammonia water and citric acid as starting materials. This method effectively solves the problems caused by solid-state reaction at high temperature and hard agglomerates brought by the chemical precipitation method. The powders were characterized by TG-DTA, XRD, FT-IR, TEM respectively and the photoluminescence (PL) spectra of (Nd0.01Y0.99)3Al5O12 green and sintered ceramic disks were measured. The results show that the forming temperature of YAG crystal phase is 850 ℃ and YAP crystal phase appearing during the calcinations transforms to pure YAG at 1050 ℃. The particle size of the powders synthesized by the LCS is in a range of 20~50 nm depending on the thermal treatment temperatures. The effectively induced cross section (σin) with the value 4.03×10-19 cm2 of (Nd0.01Y0.99)3Al5O12 ceramics is about 44% higher than that of single crystal. 展开更多
关键词 laser ceramics neodymium-doped yttrium aluminum garnet (Nd∶YAG) nano-sized powders low temperature combustion synthesis (LCS)
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Seed-Assisted Synthesis and Catalytic Performance of Nano-sized ZSM-5 Aggregates in a One-Step Crystallization Process 被引量:2
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作者 Ziyang Wang Yaquan Wang +8 位作者 Chao Sun Aijuan Zhao Cui Wang Xu Zhang Jingjing Zhao Taotao Zhao Wenrong Liu Jiaxin Lu Shuhui Wu 《Transactions of Tianjin University》 EI CAS 2020年第4期292-304,共13页
Hierarchical nano-sized ZSM-5 aggregates were successfully synthesized via a seed-assisted method in the presence of cetyltrimethylammonium bromide(CTAB)through a facile one-step crystallization process.Commercial ZSM... Hierarchical nano-sized ZSM-5 aggregates were successfully synthesized via a seed-assisted method in the presence of cetyltrimethylammonium bromide(CTAB)through a facile one-step crystallization process.Commercial ZSM-5 zeolites with a SiO2/Al2O3 ratio comparable to that of ZSM-5 products were treated with alkali and used as the seed particles.The influences of crystallization conditions were investigated,and the possible synthesis mechanism was proposed.ZSM-5 zeolites with diff erent amounts of CTAB added were characterized using many techniques and evaluated in toluene alkylation with methanol.The results showed that a trace amount of CTAB signifi cantly promoted the crystallization of ZSM-5 zeolite,with the morphology changing from hexagonal-shape crystals to uniform spherical aggregates.CTAB may act as the structure-directing agent and assemble the primary crystallites to generate hierarchical ZSM-5 aggregates.The ZSM-5 zeolite with the smallest primary particles of 50-80 nm exhibited large specific surface area,abundant mesopores,and the greatest microporosity.The hierarchical nano-sized ZSM-5 aggregate showed higher toluene conversion and a longer lifetime without compromising the selectivity to xylene and p-xylene in toluene alkylation with methanol. 展开更多
关键词 Hierarchical ZSM-5 nano-sized aggregates Seed-assisted CTAB Toluene alkylation with methanol
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Fabrication of Fine-Grained Si_3N_4-Si_2N_2O Composites by Sintering Amorphous Nano-sized Silicon Nitride Powders 被引量:4
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作者 骆俊廷 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2006年第3期97-99,共3页
Si3N4-Si2N2O composites were fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering ( LPS ). The Si2 N2O phase was generated by an in-situ reaction 2 Si3 N4 ( s ) + 1.5 02 ( g... Si3N4-Si2N2O composites were fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering ( LPS ). The Si2 N2O phase was generated by an in-situ reaction 2 Si3 N4 ( s ) + 1.5 02 ( g ) = 3 Si2 N2O ( s ) + N2 ( g ) . The content of Si2 N2 O phase up to 60% in the volume was obtained at a sintering temperature of 1 650℃ and reduced when the sintering temperature increased or decreased, indicating the reaction is reversible. The mass loss, relative density and average grain size increased with increasing the sintering temperature. The average grain size was less than 500 nm when the sintering temperature was below 1 700 ℃. The sintering procedure contains a complex crystallization and a phase transition : amorphous silicon nitride→equiaxial α- Si3 N4→ equiaxial β- Si3 N4→ rod- like Si2 N2O→ needle- like β- Si3N4 . Small round-shaped β→ Si3 N4 particles were entrapped in the Si2 N2O grains and a high density of staking faults was situated in the middle of Si2 N2O grains at a sintering temperature of 1 650 ℃. The toughness inereased from 3.5 MPa·m^1/2 at 1 600 ℃ to 7.2 MPa· m^1/2 at 1 800 ℃ . The hardness was as high as 21.5 GPa (Vickers) at 1 600 ℃ . 展开更多
关键词 Si3N4-Si2N2O composite in-situ reaction amorphous nano-sized silicon nitride
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Effect of nano-sized Al2O3 reinforcing particles on uniaxial and high cycle fatigue behaviors of hot-forged AZ31B magnesium alloy 被引量:5
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作者 M.DAREINI A.H.JABBARI M.SEDIGHI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第5期1249-1266,共18页
The effect of hot-forging process was investigated on microstructural and mechanical properties of AZ31 B alloy and AZ31 B/1.5 vol.%Al2 O3 nanocomposite under static and cycling loading. The as-cast alloy and composit... The effect of hot-forging process was investigated on microstructural and mechanical properties of AZ31 B alloy and AZ31 B/1.5 vol.%Al2 O3 nanocomposite under static and cycling loading. The as-cast alloy and composite were firstly subjected to a homogenization heat treatment at 450 ℃ and then an open-die forging at 450 ℃. The results indicated that the presence of reinforcing particles led to grain refinement and improvement of dynamic recrystallization. The forging process was more effective to eliminate the porosity in the cast alloy workpiece. Microhardness of the forged composite was increased by up to 80% and 16%, in comparison with those of the cast and forged alloy samples, respectively. Ultimate tensile strength and maximum tensile strain of the composite were improved by up to 45% and 23%, compared with those of the forged alloy in similar regions. These enhancements were respectively 50% and 37% in the compression test. The composite exhibited a fatigue life improvement in the region with low applied strain;however, a degradation was observed in the high applied strain region. Unlike AZ31 B samples, tensile, compressive and high cycle fatigue behaviors of the composite showed less sensitivity to the applied strain, which can be attributed to the amount of porosity in the samples before and after the hot-forging. 展开更多
关键词 magnesium matrix nanocomposite AZ31B alloy nano-sized Al2O3 open-die hot-forging high cycle fatigue mechanical properties microstructural evolution
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Fluoride-mediated nano-sized high-silica ZSM-5 as an ultrastable catalyst for methanol conversion to propylene 被引量:1
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作者 Junjie Li Min Liu +2 位作者 Xinwen Guo Chengyi Dai Chunshan Song 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2018年第4期1225-1230,共6页
Fluoride mediated nano-sized ZSM-5 (ZSM-5-F) with a high Si/AI ratio of 181 was fabricated using a seed-induction method and evaluated the catalysis of the methanol to propylene (MTP) reaction. High propylene sele... Fluoride mediated nano-sized ZSM-5 (ZSM-5-F) with a high Si/AI ratio of 181 was fabricated using a seed-induction method and evaluated the catalysis of the methanol to propylene (MTP) reaction. High propylene selectivity (45%) was similar to ZSM-5-OH synthesized via a hydroxide route. However, ZSM- 5-F showed much longer lifetime (305 h) compared with ZSM-5-OH (157 h) in spite of similar crystal size and aluminum content. Characterization by NH3-TPD. Py-IR, OH-IR, SEM, TG-DTA, XRD and 1H MAS NMR techniques indicated that the enhanced catalytic performance of ZSM-S-F is attributed to the fewer structural defects in the form of internal silanol groups and silanol nests. 展开更多
关键词 Fluoride route nano-sized High Si/Al Structural defects MTP
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Preparation and Mechanical Properties of Micro- and Nano-sized SiC/Fluoroelastomer Composites 被引量:1
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作者 率志君 刘志刚 +5 位作者 WANG Donghua ZHOU Pan LI Wanyou QIAO Yingjie LIU Ruiliang ZHOU Shi 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2013年第4期658-663,共6页
Microand nano-sized SiC/fluoroelastomer (FKM) composites were prepared by a mechanical mixing method. These composites were first characterized by a rotorless rheometer. Then the effects of micro- and nano-sized SiC... Microand nano-sized SiC/fluoroelastomer (FKM) composites were prepared by a mechanical mixing method. These composites were first characterized by a rotorless rheometer. Then the effects of micro- and nano-sized SiC on hardness, static and dynamic mechanical properties of the composites were investigated. The increasing amount of the SiC filler increased the curing efficiency of the biphenyl curing system, which was evident from the rheometric properties of the resulting composites. The tensile properties of composite increased with the increasing of micro- and nano-sized SiC content. When the micro- and nano-sized SiC content was higher than 20 phr, the composites showed almost unchanged tensile properties. The increasing of the tensile property was mainly attributed to the well dispersed micro- and nano-sized SiC particles characterized by SEM images. Compared to pure FKM, the composites exhibited a higher glass transition temperature and lower tan peak value. 展开更多
关键词 fluoroelastomer (FKM) micro- and nano-sized SiC composites mechanical properties
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A Facile Route for Synthesis of LiFePO_4/C Cathode Material with Nano-sized Primary Particles 被引量:1
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作者 肖政伟 胡国荣 +1 位作者 杜柯 彭忠东 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第5期590-595,共6页
A facile and practical route was introduced to prepare LiFePO4/C cathode material with nano-sized primary particles and excellent electrochemical performance. LiH2PO4 was synthesized by using H3PO4 and LiOH as raw mat... A facile and practical route was introduced to prepare LiFePO4/C cathode material with nano-sized primary particles and excellent electrochemical performance. LiH2PO4 was synthesized by using H3PO4 and LiOH as raw materials. Then, as-prepared LiH2PO4, reduced iron powder andα-D-glucose were ball-milled, dried and sin-tered to prepare LiFePO4/C. X-ray diffractometry was used to characterize LiH2PO4, ball-milled product and LiFePO4/C. Differential scanning calorimeter-thermo gravimetric analysis was applied to investigate possible reac-tions in sintering and find suitable temperature for LiFePO4 formation. Scanning electron microscopy was em-ployed for the morphology of LiFePO4/C. As-prepared LiH2PO4 is characterized to be in P21cn(33) space group, which reacts with reduced iron powder to form Li3PO4, Fe3(PO4)2 and H2 in ball-milling and sintering. The appro-priate temperature for LiFePO4/C synthesis is 541.3-976.7 ℃. LiFePO4/C prepared at 700 ℃ presents nano-sized primary particles forming aggregates. Charge-discharge examination indicates that as-prepared LiFePO4/C displays appreciable discharge capacities of 145 and 131 mA·h·g^-1 at 0.1 and 1 C respectively and excellent discharge ca-pacity retention. 展开更多
关键词 lithium ion cell reduced iron powder ball-milling LIFEPO4/C nano-sized primary particle
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Enhancing the Deactivation Durability of Nano-sized HZSM-5 for Aromatization by Adjusting its Ratio of Lewis/Brφnsted Acid Sites
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作者 ZhouBoXU HongChenGUO +3 位作者 XiangShengWANG PeiQingZHANG LePingZHAO YongKangHU 《Chinese Chemical Letters》 SCIE CAS CSCD 2004年第9期1123-1126,共4页
Ratio of Lewis/Brfnsted acid sites (Cl/Cb) on the surface of nano-sized HZSM-5 was successfully manipulated by means of steaming and acid leaching. Significant enhancement of the deactivation durability of nano-sized... Ratio of Lewis/Brfnsted acid sites (Cl/Cb) on the surface of nano-sized HZSM-5 was successfully manipulated by means of steaming and acid leaching. Significant enhancement of the deactivation durability of nano-sized HZSM-5 in the aromatization of fluid catalytic cracking (FCC) gasoline olefins seems to be closely related to the increase of Lewis/Brfnsted acid sites ratio. 展开更多
关键词 Lewis acid Brfnsted acid nano-sized HZSM-5 AROMATIZATION gasoline.
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Mechanism of expanding swept volume by nano-sized oil-displacement agent
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作者 LEI Qun LUO Jianhui +6 位作者 PENG Baoliang WANG Xiaocong XIAO Peiwen WANG Pingmei HE Lipeng DING Bin GENG Xiangfei 《Petroleum Exploration and Development》 2019年第5期991-997,共7页
The effect of expanding swept volume by iNanoW1.0 nanoparticles in ultra-low permeability core was studied by low-field nuclear magnetic resonance(LF-NMR)technology,and the mechanism of expanding swept volume was expl... The effect of expanding swept volume by iNanoW1.0 nanoparticles in ultra-low permeability core was studied by low-field nuclear magnetic resonance(LF-NMR)technology,and the mechanism of expanding swept volume was explained by oxygen spectrum nuclear magnetic resonance(17O-NMR)experiments and capillarity analysis.The results of the LF-NMR experiment show that the nano-sized oil-displacement agent iNanoW1.0 could increase the swept volume by 10%-20%on the basis of conventional water flooding,making water molecules get into the low permeable region with small pores that conventional water flooding could not reach.17O-NMR technique and capillary analysis proved that iNanoW1.0 nanoparticles could weaken the association of hydrogen bonds between water molecules,effectively change the structure of water molecular clusters,and thus increasing the swept volume in the low permeable region.The ability of weakening association of hydrogen bonds between water molecules of iNanoW1.0 nanoparticles increases with its mass fraction and tends to be stable after the mass fraction of 0.1%. 展开更多
关键词 nanoparticles nano-sized oil-displacement AGENT WATER FLOODING swept volume WATER molecular hydrogen bonding capillary action
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Combustion and Ball Milled Synthesis of Rare Earth Nano-Sized Ceria Powder
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作者 Ranjan Sen Siddhartha Das Karabi Das 《Materials Sciences and Applications》 2011年第5期416-420,共5页
This paper reports a study on nanocrystalline ceria powder prepared by high energy ball-milling and combustion synthesis methods. The combustion synthesis was carried out using ceric ammonium nitrate as oxidizer and c... This paper reports a study on nanocrystalline ceria powder prepared by high energy ball-milling and combustion synthesis methods. The combustion synthesis was carried out using ceric ammonium nitrate as oxidizer and citric acid, glycine or citric acid plus glycine as fuel. The minimum crystallite size of ceria powder is obtained by combustion synthesis of ceric ammonium nitrate and citric acid. The ceria powder produced by combustion synthesis of ceric ammonium nitrate and citric acid and glycine has less agglomeration of particles than other techniques. 展开更多
关键词 Ceramics BALL MILLING COMBUSTION Synthesis nano-sized CERIA X-Ray Diffraction
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Influence of nano-SiC on microstructure and property of MAO coating formed on AZ91D magnesium alloy 被引量:12
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作者 王淑艳 司乃潮 +1 位作者 夏永平 刘莉 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第6期1926-1934,共9页
Ceramic coating incorporated with nano-SiC was obtained on AZ91D magnesium alloy during MAO by adding nano-SiC into the silicate-aluminate-based composite electrolyte. The microstructure, thickness, phase analysis, el... Ceramic coating incorporated with nano-SiC was obtained on AZ91D magnesium alloy during MAO by adding nano-SiC into the silicate-aluminate-based composite electrolyte. The microstructure, thickness, phase analysis, element composition and hardness of the coatings were respectively investigated by scanning electron microscopy(SEM), film thickness meter, X-ray diffraction (XRD), energy disperse spectroscopy(EDS) and Vickers hardness tester. The wear resistance of Mg alloy and coatings were evaluated by friction and wear apparatus, while the corrosion resistance of Mg alloy and coatings were evaluated by potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). The results show that after adding nano-SiC into the electrolyte, both the striking voltage and final voltage decrease, the size and number of the micropore on the surface of the coating decrease, the thickness and hardness of the coating increase, both the wear resistance and corrosion resistance of the coating raise. 展开更多
关键词 magnesium alloy micro-arc oxidation nano-sIC microstructure PROPERTY
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