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Synthesis and Characterization of Cerium-Doped Lutetium Aluminum Garnet Phosphors by Nitrate-citrate Sol-Gel Combustion Process 被引量:4
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作者 李会利 刘学建 +1 位作者 张其土 黄莉萍 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第4期401-406,共6页
Nanosized cerium-doped lutetium aluminum garnet (LuAG:Ce) phosphors were prepared by nitrate-citrate solgel combustion process using 1:1 ratio of the citrate:nitrate. The prepared LuAG:Ce phosphors were characte... Nanosized cerium-doped lutetium aluminum garnet (LuAG:Ce) phosphors were prepared by nitrate-citrate solgel combustion process using 1:1 ratio of the citrate:nitrate. The prepared LuAG:Ce phosphors were characterized by XRD, TEM, photoluminescence and radioluminescence spectra excited by UV and X-ray, respectively. The purified crystalline phase of LuAG:Ce was obtained at 900 ℃ by directly crystallizing from amorphous materials. The resultant Lu- AG:Ce phosphors were uniform and had good dispersivity with an average particle size of about 30 urn. Both photoluminescence and radioluminescence were well-known Ce^3+ emissions located in the range of 470 -600 nm consisting of two emission bands because of the transition from the lowest 5d excited state (2D) to the 4f ground state of Ce^3+, which matched well with the sensitivity curve of the Si-photodiode. There was a little red shift for the emission components from the UV-excited emission spectrum to the X-ray-excited emission spectrum. The fast scintillation decay component of 26 ns satisfies the requirements of fast scintillators. 展开更多
关键词 LuAG:Ce phosphors sol-gel combustion process photoluminescence RADIOLUMINESCENCE rare earths
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Study of the Combustion Process inside an Ethanol-Diesel Dual Direct Injection Engine Based on a Non-Uniform Injection Approach
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作者 Liying Zhou Yu Liang 《Fluid Dynamics & Materials Processing》 EI 2021年第1期159-170,共12页
The use of ethanol is a promising method to reduce the emissions of diesel engines.The present study has been based on the installation of a gasoline electronic injection system in a single-cylinder diesel engine to c... The use of ethanol is a promising method to reduce the emissions of diesel engines.The present study has been based on the installation of a gasoline electronic injection system in a single-cylinder diesel engine to control the amount of ethanol entering the cylinder during the compression(while diesel has been injected into the cylinder by the original pump injection system).The injection time has been controlled by crank angle signal collected by an AVL angle indicator.In the tests ethanol and diesel each accounted for half of the fuel volume,and the total heat energy supply of the fuel was equivalent to that of the diesel under the operating conditions of the original engine.A three-dimensional combustion model of the diesel engine has been implemented by using the CFD software FIRE.Simulations have been carried out assuming uniform and non-uniform injections rate for the different holes and the different results have been compared.According to these results,a non-uniform injection rate can produce early ignition and cause an increase in the maximum in-cylinder pressure and the maximum average incylinder temperature.Moreover,in such conditions NO emissions are larger while soot emission is slightly lower. 展开更多
关键词 combustion process dual direct injection DIESEL ETHANOL injection rate
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The Process of a Laser-Supported Combustion Wave Induced by Millisecond Pulsed Laser on Aluminum Alloy 被引量:1
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作者 张巍 魏智 +1 位作者 王翼斌 金光勇 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第1期60-62,共3页
We study the process of a laser-supported combustion wave (LSCW) when an aluminum alloy is irradiated by a millisecond pulse laser based on the method of laser shadowgraphy. Under the condition of different laser pa... We study the process of a laser-supported combustion wave (LSCW) when an aluminum alloy is irradiated by a millisecond pulse laser based on the method of laser shadowgraphy. Under the condition of different laser parameters, the obtained results include the velocity, ignition threshold of LSCW and the variation law. The speed of LSCW increases with the laser energy under the same irradiation laser pulse width, and the speed of LSCW reduces with the increase of the laser pulse width under the same irradiation laser energy. Moreover, the ignition time of LSCW becomes shorter by increasing the laser number of the pulse and is not effected by changing the frequencies, when keeping the laser pulse width and energy unchanged. The results of the study can be applied in the laser propulsion technology and metal surface laser heat treatment, etc. 展开更多
关键词 of as in TIME is by The process of a Laser-Supported combustion Wave Induced by Millisecond Pulsed Laser on Aluminum Alloy on
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Absorption Property of YAG∶Sm Phosphors Prepared using Sol-Gel Combustion Method
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作者 沐磊 黄芸 +1 位作者 王丽熙 张其土 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第S2期9-12,共4页
Samarium-doped yttrium aluminum garnet (YAG∶Sm3+) phosphors were synthesized by nitrate-citrate sol-gel combustion method. Phase evolution, morphology and absorbency of the obtained materials were characterized by XR... Samarium-doped yttrium aluminum garnet (YAG∶Sm3+) phosphors were synthesized by nitrate-citrate sol-gel combustion method. Phase evolution, morphology and absorbency of the obtained materials were characterized by XRD, FESEM, reflection spectrum, respectively. The experimental results showed that single-phase cubic YAG∶Sm3+ crystalline was directly obtained at 800 ℃ from amorphous precursor, and mostly developed at 900 ℃. The prepared powders were relatively agglomerated with an average particle size of 300 nm. The reflection spectrum showed that there were several apparent characteristic absorption peaks due to the 4f→4f inner shell electron transitions from the 6H5/2 ground state to 6FJ (J=9/2, 7/2 and 5/2) excited state of Sm3+. Moreover, the intensity of the characteristic peaks was enhanced with the increasing concentration of Sm3+ ions. 展开更多
关键词 ABSORPTION YAG sol-gel combustion process rare earths
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THERMAL DEGRADATION AND FLAME RETARDANCY OF CALCIUM ALGINATE FIBERS 被引量:5
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作者 于建 夏延致 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2009年第6期807-812,共6页
Calcium alginate fibers were prepared by wet spinning of sodium alginate into a coagulating bath containing calcium chloride.The thermal degradation and flame retardancy of calcium alginate fibers were investigated wi... Calcium alginate fibers were prepared by wet spinning of sodium alginate into a coagulating bath containing calcium chloride.The thermal degradation and flame retardancy of calcium alginate fibers were investigated with thermal gravimetry(TG),X-ray diffraction(XRD),limiting oxygen index(LOI) and cone calorimeter(CONE).The results show that calcium alginate fibers are inherently flame retardant with a LOI value of 34,and the heat release rate(HRR),total heat release(THR),CO and CO_2 concentrations during com... 展开更多
关键词 Calcium alginate fiber Flame retardancy Wet spinning combustion process Thermal degradation
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Research on the Fe-silicon nitride material self-producing N_2 at high temperature 被引量:1
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作者 Junhong Chen Xueda Wang +2 位作者 Jialin Sun Huasheng Zhan Wen Song 《Journal of University of Science and Technology Beijing》 CSCD 2006年第1期78-81,共4页
The Fe silicon nitride synthesized by flashing combustion process was studied to determine the reaction temperature between Fe and silicon nitride, the account of N2 given out in the course of the reaction, and the ch... The Fe silicon nitride synthesized by flashing combustion process was studied to determine the reaction temperature between Fe and silicon nitride, the account of N2 given out in the course of the reaction, and the change of the microstructure during calcination. The results showed that at 1127.2℃ the Fe-silicon nitride self-reacts and releases N2 and under 101.3 kPa the volume of N2 given out in the course of the reaction is 20 times more than that of the starting material. N2 is produced quickly, and completes in several decade seconds. With the producing of N2, the structure of Silicon Nitride around Fe becomes loose and porous, or cracks are formed by the reaction between Fe and silicon nitride. So if it is made use of that Fe-silicon nitride self-producing N2 at the high temperature, the performance of the material on a base of Fe-silicon nitride could be greatly improved. 展开更多
关键词 synthesis by flashing combustion process Fe-Silicon Nitride NITROGEN
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Numerical Simulation of the High-Boosting Influence on Mixing,Combustion and Emissions of High-Power-Density Engine 被引量:2
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作者 WANG Can YUE Zongyu +3 位作者 ZHAO Yuanyuan YE Ying LIU Xinlei LIU Haifeng 《Journal of Thermal Science》 SCIE EI CAS CSCD 2023年第3期933-946,共14页
Future high-power-density engines require high level of intake boost.However,the effects of boosting on mixing,combustion and emissions in existing studies are inconsistent.In this paper,the mixing,combustion and emis... Future high-power-density engines require high level of intake boost.However,the effects of boosting on mixing,combustion and emissions in existing studies are inconsistent.In this paper,the mixing,combustion and emission characteristics with intake pressures of 100-400 kPa at low,medium and high loads are studied.The results show that the increase of intake pressures is conducive to the enhancement of air entrainment,while the air utilization ratios are reduced,thus requiring injection pressure to be optimized to effectively improve the mixing.For the intake pressures of 100 kPa,the average chemical reaction path is low-temperature reaction route,while the path of higher intake pressures is dominated by high-temperature pyrolysis.For soot emissions,when the equivalence ratio is lower than 0.175,the oxygen in the cylinder is suficient,so the effect of temperature decrease is more significant,which leads to the increase of soot emissions with the increase of intake pressures.Otherwise,the effect of increasing oxygen concentration is more significant,so soot decreases accordingly.When the peak of global temperature is lower than 1800 K,the effect of the increase of oxygen concentration is more dominant,so the NO_(x)emission increases with the increase of intake pressures.Otherwise,the rule of NOxemissions is consistent with temperature changes. 展开更多
关键词 high-power-density engines high boosting mixing process combustion process EMISSIONS
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Laser absorption spectroscopy for high temperature H_2O time-history measurement at 2.55 μm during oxidation of hydrogen
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作者 Yu-Dan Gou De-Xiang Zhang +3 位作者 Yi-Jun Wang Chang-Hua Zhang Ping Li Xiang-Yuan Li 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第7期376-381,共6页
Concentration time-histories of H20 were measured behind reflected shock waves during hydrogen combustion. Experiments were conducted at temperatures of 1117-1282 K, the equivalence ratios of 0.5 and 0.25, and a press... Concentration time-histories of H20 were measured behind reflected shock waves during hydrogen combustion. Experiments were conducted at temperatures of 1117-1282 K, the equivalence ratios of 0.5 and 0.25, and a pressure at 2 atm using a mixture of H2/O2 highly diluted with argon. H2O was monitored using tunable mid-infrared diode laser absorption at 2.55 μm (3920.09 cm-1). These time-histories provide kinetic targets to test and refine reaction mechanisms for hydrogen. Comparisons were made with the predictions of four detailed kinetic mechanisms published in the last four years. Such comparisons of H2O concentration profiles indicate that the AramcoMech 2.0 mechanism yields the best agreement with the experimental data, while CRECK, San Diego, and HP-Mech mechanisms show significantly poor predictions. Reaction pathway analysis for hydrogen oxidation indicates that the reaction H + OH + M = H20 + M is the key reaction for controlling the H2O formation by hydrogen oxidation. It is inferred that the discrepancy of the conversion percentage from H to H20 among these four mechanisms induces the difference of performance on H2O time-history predictions. This work demonstrates the potential of time-history measurement for validation of large reaction mechanisms. 展开更多
关键词 tunable diode laser absorption spectroscopy H20 time-history profile combustion process reac- tion mechanism
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Construction of a macromolecular structural model of Chinese lignite and analysis of its low-temperature oxidation behavior 被引量:11
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作者 Xianliang Meng Mingqiang Gao +6 位作者 Ruizhi Chu Zhenyong Miao Guoguang Wu Lei Bai Peng Liu Yuanfang Yan Pengcheng Zhang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第9期1314-1321,共8页
The aim of this paper is to analyze the change in the active structure of lignite during the process of lowtemperature oxidation by constructing a molecular structure model for lignite. Using quantum computation combi... The aim of this paper is to analyze the change in the active structure of lignite during the process of lowtemperature oxidation by constructing a molecular structure model for lignite. Using quantum computation combined with experimental results of proximate analysis, ultimate analysis, Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS), a structural model for the large molecular structure was constructed. By analyzing the bond lengths in the model molecule, the evolution law for the active structure of lignite was predicted for the process of low-temperature oxidation. In low-temperature oxidation,alkanes and hydroxyls are the primary active structures observed in lignite, though ether may also react. These active functional groups react with oxygen to release heat, thereby speeding up the reaction between coal and oxygen. Finally, the content of various functional groups in the process of lignite low-temperature oxidation was analyzed by infrared analysis, and the accuracy of the model was verified. 展开更多
关键词 Chinese lignite Coal combustion Molecular simulation Low-temperature oxidation process Environment
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Modeling droplet vaporization and combustion with the volume of fluid method at a small Reynolds number 被引量:2
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作者 Xiao-bin ZHANG Wei ZHANG Xue-jun ZHANG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2012年第5期361-374,共14页
The volume of fluid(VOF) formulation is applied to model the combustion process of a single droplet in a hightemperature convective air free stream environment.The calculations solve the flow field for both phases,and... The volume of fluid(VOF) formulation is applied to model the combustion process of a single droplet in a hightemperature convective air free stream environment.The calculations solve the flow field for both phases,and consider the droplet deformation based on an axisymmetrical model.The chemical reaction is modeled with one-step finite-rate mechanism and the thermo-physical properties for the gas mixture are species and temperature dependence.A mass transfer model applicable to the VOF calculations due to vaporization of the liquid phases is developed in consideration with the fluctuation of the liquid surface.The model is validated by examining the burning rate constants at different convective air temperatures,which accord well with experimental data of previous studies.Other phenomena from the simulations,such as the transient history of droplet deformation and flame structure,are also qualitatively accordant with the descriptions of other numerical results.However,a different droplet deformation mechanism for the low Reynolds number is explained compared with that for the high Reynolds number.The calculations verified the feasibility of the VOF computational fluid dynamics(CFD) formulation as well as the mass transfer model due to vaporization. 展开更多
关键词 DROPLET VAPORIZATION combustion process Volume of fluid(VOF) Numerical simulation
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MgO-based adsorbents for CO2 adsorption:Influence of structural and textural properties on the CO_2 adsorption performance 被引量:4
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作者 Gutiérrez-Bonilla Elvira Granados-Correa Francisco +1 位作者 Sánchez-Mendieta Víctor Morales-Luckie Raúl Alberto 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2017年第7期418-428,共11页
A series of MgO-based adsorbents were prepared through solution–combustion synthesis and ball-milling process.The prepared MgO-based powders were characterized using X-ray diffraction,scanning electron microscopy,N_2... A series of MgO-based adsorbents were prepared through solution–combustion synthesis and ball-milling process.The prepared MgO-based powders were characterized using X-ray diffraction,scanning electron microscopy,N_2 physisorption measurements,and employed as potential adsorbents for CO_2 adsorption.The influence of structural and textural properties of these adsorbents over the CO_2 adsorption behaviour was also investigated.The results showed that MgO-based products prepared by solution–combustion and ball-milling processes,were highly porous,fluffy,nanocrystalline structures in nature,which are unique physico-chemical properties that significantly contribute to enhance their CO_2 adsorption.It was found that the MgO synthesized by solution combustion process,using a molar ratio of urea to magnesium nitrate(2:1),and treated by ball-milling during 2.5 hr(MgO-BM2.5h),exhibited the maximum CO_2 adsorption capacity of 1.611 mmol/g at 25℃ and 1 atm,mainly via chemisorption.The CO_2 adsorption behaviour on the MgO-based adsorbents was correlated to their improved specific surface area,total pore volume,pore size distribution and crystallinity.The reusability of synthesized MgO-BM2.5h was confirmed by five consecutive CO_2adsorption–desorption times,without any significant loss of performance,that supports the potential of MgO-based adsorbent.The results confirmed that the special features of MgO prepared by solution–combustion and treated by ball-milling during 2.5 hr are favorable to be used as effective MgO-based adsorbent in post-combustion CO_2 capture technologies. 展开更多
关键词 CO_2 adsorption MgO-based adsorbents Porous materials Solution–combustion synthesis Ball-milling process Textural properties
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Synthesis of ZrC Nanoparticles in the ZrO_2–Mg–C–Fe System Through Mechanically Activated Self-Propagating High-Temperature Synthesis
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作者 Abdollah Hajalilou Mansor Hashim +3 位作者 Halimah Mohamed kamari Kazem Javadi Samikannu Kanagesan Mohammad Parastegari 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2014年第6期1144-1151,共8页
ZrC nanoparticles in the matrix of Fe were produced by the mechanically activated self-propagating hightemperature method using ZrO2/C/Mg/Fe powder mixtures. The effects of milling time, Fe content, and combustion tem... ZrC nanoparticles in the matrix of Fe were produced by the mechanically activated self-propagating hightemperature method using ZrO2/C/Mg/Fe powder mixtures. The effects of milling time, Fe content, and combustion temperature as well as the formation route for synthesizing ZrC powder particles were studied. The samples were characterized by XRD, SEM, TEM, and DTA. The XRD results revealed that, after 18 h of mechanical activation, ZrO2/ZC/Mg/Fe reacted with the self-propagating combustion(SHS) mode at 870 °C producing the ZrC–Fe nanocomposite. It was also found that both mechanical activation and Fe content played key roles in the ZrC synthesis temperature. With a Fe content of(5–40) wt%, the SHS reaction proceeded favorably and both the ZrC formation temperature and the adiabatic temperature(Tad) decreased. The Mg O content was removed from the final products using a leaching test process by dissolving in hydrochloric and acetic acids. 展开更多
关键词 Mechanical activation(MA) combustion synthesis Fe–ZrC composite Leaching process
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