The three-way catalyst(TWC),as a promising approach to control automobile exhaust emission,has been widely studied and applied.However,it still suffers from the high light-off temperature and poor stability.Herein,we ...The three-way catalyst(TWC),as a promising approach to control automobile exhaust emission,has been widely studied and applied.However,it still suffers from the high light-off temperature and poor stability.Herein,we synthesized a multicomponent catalyst Rh/Cu-CeSn by using Cu metal doping to modify the Ce-based solid solution,which exhibited good TWC catalytic performance:the light-off temperatures for CO,NO,and C_(3)H_(6)conversion are 172℃,266℃,and 193℃,respectively.Moreover,the catalyst still maintained good activity after 12 h of the continuous reaction under high-temperature conditions.The experiments and mechanism studies reveal that due to the redox pair Cu^(+)/Cu^(2+),the Cu incorporation can effectively inhibit the Rh transition to the oxidation state and greatly enhance the catalytic activity and stability.This work provides a viable strategy for precise characteristic modulation of composite oxide supports during the fabrication of noble metal-based catalysts,which significantly reduces environmental pollution from energy applications.展开更多
Three-way concept analysis is an important tool for information processing,and rule acquisition is one of the research hotspots of three-way concept analysis.However,compared with three-way concept lattices,three-way ...Three-way concept analysis is an important tool for information processing,and rule acquisition is one of the research hotspots of three-way concept analysis.However,compared with three-way concept lattices,three-way semi-concept lattices have three-way operators with weaker constraints,which can generate more concepts.In this article,the problem of rule acquisition for three-way semi-concept lattices is discussed in general.The authors construct the finer relation of three-way semi-concept lattices,and propose a method of rule acquisition for three-way semi-concept lattices.The authors also discuss the set of decision rules and the relationships of decision rules among object-induced three-way semi-concept lattices,object-induced three-way concept lattices,classical concept lattices and semi-concept lattices.Finally,examples are provided to illustrate the validity of our conclusions.展开更多
Three-way catalysts are widely used to control criterion pollutant emissions fromthe increasing gasoline engines.With the stringent requirements of automotivepollutant emission standards in various countries,Rh has be...Three-way catalysts are widely used to control criterion pollutant emissions fromthe increasing gasoline engines.With the stringent requirements of automotivepollutant emission standards in various countries,Rh has become an irreplaceablecomponent of three-way catalysts due to its superior NOx elimination,high N2selectivity,and simultaneous elimination of CO and hydrocarbons.In this review,we systematically review the recent development of Rh-based three-way catalystsin terms of potential supports and effective active center construction strategies.We further summarize the key role of Rh metal in the three-way catalytic mechanismand reaction kinetics.Finally,we conclude the current challenges and futureopportunities facing Rh-based catalysts.It is believed that based on the deep understandingof Rh-based three-way catalysts,the design of Rh-based catalysts withgood low-temperature catalytic performance and low cost is expected to be realizedin the future.展开更多
In this paper, we propose three-way granular approximations(3WGAs) based on bisimulations. We discover the relationships between 3WGAs based on underlying relations and 3WGAs based on bisimilarity(the largest bisimula...In this paper, we propose three-way granular approximations(3WGAs) based on bisimulations. We discover the relationships between 3WGAs based on underlying relations and 3WGAs based on bisimilarity(the largest bisimulation induced by an underlying relation).展开更多
The effect of Co doping on ceria-zirconia mixed oxides was investigated for Co0.1Ce0.6Zr0.3Ox sample prepared by sol-gel method. The Pd-only three-way catalyst （TWC） was obtained by incipient wetness impregnation wi...The effect of Co doping on ceria-zirconia mixed oxides was investigated for Co0.1Ce0.6Zr0.3Ox sample prepared by sol-gel method. The Pd-only three-way catalyst （TWC） was obtained by incipient wetness impregnation with 0.5 wt.% Pd loading. The structural and oxygen handling properties were analyzed by X-ray diffraction （XRD）, H2-temperature programmed reduction （H2-TPR） and the dynamic oxygen storage capacity （DOSC）. The introduction of Co into ceria-zirconia lattice strongly modified the mobility of oxygen and enhanced the DOSC performance. Pd-only TWC based on the Co0.1Ce0.6Zr0.3Ox support exhibited superior activity for water-gas shift and steam reforming and ampli- fied amplitude of stoichiometric window.展开更多
Ce-Zr-Al-Nd2O3 （CZAN） support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffTaction （XRD）, low temperature nitrogen adsorption-desorption,...Ce-Zr-Al-Nd2O3 （CZAN） support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffTaction （XRD）, low temperature nitrogen adsorption-desorption, oxygen pulsing technique, H2-temperamre programmed reduction （H2-TPR） and X-ray photoelectron spectroscopy （XPS）. The Pd-only three-way catalysts （Pd-TWC） supported on these materials were prepared by incipient wetness method and studied by activity tests. The results demonstrated that the CZAN supports obtained by the two methods showed better structural, textural and redox properties than the CZA without Nd2O3, and the addition of Nd203 improved the catalytic activity of TWC. Especially, the CZAN-i support prepared by impregnation method had better thermal stability and redox property. Meanwhile, the Pd/CZAN-i catalyst exhibited the best catalytic performance. XPS measurements indicated that the Nd-modified samples possessed more Ce3＋ and oxygen vacancies on the surface of samples, which led to a better redox property. The excellent redox property of support materials helped to improve the catalytic activity of TWC.展开更多
Based on linguistic evaluations, a linguistic threeway decision method is proposed. First, the alternatives are rated in linguistic forms and divided into acceptance, rejection and uncertainty regions. Secondly, the l...Based on linguistic evaluations, a linguistic threeway decision method is proposed. First, the alternatives are rated in linguistic forms and divided into acceptance, rejection and uncertainty regions. Secondly, the linguistic three-way group decision steps are provided. Specifically, the experts determine the lower bound and upper bound of the uncertainty region, respectively. When the evaluation is superior to the upper bound, the corresponding alternative is put into the acceptance region directly. Similarly, when the evaluation is inferior to the lower bound, the corresponding alternative is put into the rejection region directly, and the remaining alternatives are put into the uncertain region. Moreover, the objects in the uncertainty region are especially discussed. The linguistic terms are transformed into fuzzy numbers and then aggregated. Finally, a recommendation example is provided to illustrate the practicality and validity of the proposed method.展开更多
In the purification process of automobile exhaust,existing water plays an important role as an oxidant,which converts CO and hydrocarbons（HCs） by the water-gas shift（WGS） and the steam reforming（SR） reactions,re...In the purification process of automobile exhaust,existing water plays an important role as an oxidant,which converts CO and hydrocarbons（HCs） by the water-gas shift（WGS） and the steam reforming（SR） reactions,respectively,especially at high temperatures.Meanwhile it is major component of the exhaust which can affect significantly the thermal stability of the three-way catalyst.Activity experiments were carried out close to the real operation conditions（GHSV,concentration,etc.） with a Pd/Ce0.67Zr0.33O2 catalyst supplying information on the CO and C3H8 oxidation reactions in feedstream formed by different reactant combinations.The obtained results showed that the activity of the CO and C3H8 oxidation was promoted by the addition of steam due to the WGS and SR reactions.The WGS and SR reaction were competitive under oxygen-lean conditions.The kinetic analysis was considered for WGS and SR reactions.展开更多
Three-way pipes, T and Y pipes, are very important connecting components in pipeline systems, their strength are related to the safety of pipelines. In the case that crack is not detected in the three-way pipe, ANSYS ...Three-way pipes, T and Y pipes, are very important connecting components in pipeline systems, their strength are related to the safety of pipelines. In the case that crack is not detected in the three-way pipe, ANSYS finite element program version 5.6 is applied to study the stress distribution of the three-way pipe and to obtain the optimum fillet radius in the crotch region of the two pipes. The reasonable intersection angle of the two pipes is also obtained. In the case that a surface crack is detected in the three-way pipe, the maximum stress intensity factor (SIF) near the front of the surface crack is studied.展开更多
FeOx-CeO2 mixed oxides with increasing Fe/（Ce＋Fe） atomic ratio （1-20 mol%） were prepared by sol-gel method and characterized by X-ray powder diffraction （XRD）, Brunauer-Emrnett-Teller （BET） and Hydrogen tempe...FeOx-CeO2 mixed oxides with increasing Fe/（Ce＋Fe） atomic ratio （1-20 mol%） were prepared by sol-gel method and characterized by X-ray powder diffraction （XRD）, Brunauer-Emrnett-Teller （BET） and Hydrogen temperature-programmed reduction （H2-TPR） techniques. The dynamic oxygen storage capacity （DOSC） was investigated by mass spectrometry with CO/O2 transient pulses. The powder XRD data following Rietveld refinement revealed that the solubility limit of iron oxides in the CeO2 was 5 mol% based on Fe/（Ce＋Fe）. The lattice parameters experienced a decrease followed by an increase due to the influence of the maximum solubility limit of iron oxides in the CeO2. TPR analysis revealed that Fe introduction into ceria strongly modified the textual and structural properties, which influenced the oxygen handling properties. DOSC results revealed that Ce-based materials containing Fe oxides with multiple valences contribute to the majority of DOSC. The kinetic analysis indicated that the calculated apparent kinetic parameters obey the compensation effect. The three-way catalytic performance for Pd-only catalysts based on the Fe doping support exhibited the redundant iron species separated out of the CeO2 and interacted with the ceria and Pd species on the surface, which seriously influenced the catalytic properties, especially after hydrothermal aging treatment.展开更多
Real-time resource allocation is crucial for phased array radar to undertake multi-task with limited resources,such as the situation of multi-target tracking,in which targets need to be prioritized so that resources c...Real-time resource allocation is crucial for phased array radar to undertake multi-task with limited resources,such as the situation of multi-target tracking,in which targets need to be prioritized so that resources can be allocated accordingly and effectively.A three-way decision-based model is proposed for adaptive scheduling of phased radar dwell time.Using the model,the threat posed by a target is measured by an evaluation function,and therefore,a target is assigned to one of the three possible decision regions,i.e.,positive region,negative region,and boundary region.A different region has a various priority in terms of resource demand,and as such,a different radar resource allocation decision is applied to each region to satisfy different tracking accuracies of multi-target.In addition,the dwell time scheduling model can be further optimized by implementing a strategy for determining a proper threshold of three-way decision making to optimize the thresholds adaptively in real-time.The advantages and the performance of the proposed model have been verified by experimental simulations with comparison to the traditional twoway decision model and the three-way decision model without threshold optimization.The experiential results demonstrate that the performance of the proposed model has a certain advantage in detecting high threat targets.展开更多
As the oxygen redox ability shows great effects on the catalytic performances of ceria-zirconia based materials,many strategies have been utilized to improve the oxygen storage capacity.Here in this study,we report a ...As the oxygen redox ability shows great effects on the catalytic performances of ceria-zirconia based materials,many strategies have been utilized to improve the oxygen storage capacity.Here in this study,we report a simple and facile approach to prepare a SO_(4)^(2-)-modified La,Y-doped ceria-zirconia material(SO/CZLY-f)with high oxygen storage capacity.Due to the additional redox process between SO_(4)^(2-)and S^(2-),oxygen storage capacity of SO/CZLY-f(745.3μmol O_(2)/g)is about 1.6 times higher than that of La,Ydoped ceria-zirconia material without SO_(4)^(2-)modification.Moreover,the catalytic activities and stability of the corresponding Pd-only three-way catalyst were measured.Compared to that of Pd@CZLY-f,the operation window of CO,full conversion temperature of HC and NO over Pd@SO/CZLY-f are obviously widened and lowered,respectively.After aging treatment at 1100℃for 4 h,the superiority of aged Pdloading composite is still maintained.展开更多
Ceria-zirconia-alumina （CZA） solid solution was prepared by sol-gel method in the present study. 0.5 wt.% Pd supported on CZA was prepared by incipient wetness impregnation. The steam effects for CO and C3H8 oxidati...Ceria-zirconia-alumina （CZA） solid solution was prepared by sol-gel method in the present study. 0.5 wt.% Pd supported on CZA was prepared by incipient wetness impregnation. The steam effects for CO and C3H8 oxidation, three-way catalytic activity and stoichiometric window property were studied. The light-off temperature of the CO oxidation reaction shifted to a lower temperature due to the water-gas shift （WGS） reactions. The oxidation of C3H8 was enhanced due to the steam reforming （SR） reactions. The steam promoted the C3H8 oxidation and NO reduction in three-way catalytic reaction. The amplitude of stoichiometric window was amplified by the addition of water to the feed stream.展开更多
Three-way decision(T-WD)theory is about thinking,problem solving,and computing in threes.Behavioral decision making(BDM)focuses on effective,cognitive,and social processes employed by humans for choosing the optimal o...Three-way decision(T-WD)theory is about thinking,problem solving,and computing in threes.Behavioral decision making(BDM)focuses on effective,cognitive,and social processes employed by humans for choosing the optimal object,of which prospect theory and regret theory are two widely used tools.The hesitant fuzzy set(HFS)captures a series of uncertainties when it is difficult to specify precise fuzzy membership grades.Guided by the principles of three-way decisions as thinking in threes and integrating these three topics together,this paper reviews and examines advances in three-way behavioral decision making(TW-BDM)with hesitant fuzzy information systems(HFIS)from the perspective of the past,present,and future.First,we provide a brief historical account of the three topics and present basic formulations.Second,we summarize the latest development trends and examine a number of basic issues,such as one-sidedness of reference points and subjective randomness for result values,and then report the results of a comparative analysis of existing methods.Finally,we point out key challenges and future research directions.展开更多
Oxygen storage-capacity （OSC）, oxygen buffer capacity （OBC）, X-my diffraction and electron diffraction pattern, high resolution electron microscopy were used to study the quaternary oxides, i .e., of Ce, Tb, Pr an...Oxygen storage-capacity （OSC）, oxygen buffer capacity （OBC）, X-my diffraction and electron diffraction pattern, high resolution electron microscopy were used to study the quaternary oxides, i .e., of Ce, Tb, Pr and Zr. （Ce0.6 Tb0.2Zr0.2O2- δ and Ce0.6Pr0.2Zr0.2O2-δ ）. OSC and OBC data indicate that these oxides have very good oxygen transfer capacity （OTC） and their pseudo-solid solutions exhibit fluorite-type structure. These oxides may act as a good candidate for three-way catalysts （TWC）.展开更多
The durability of three-way catalyst （TWC） and corresponding close-coupled catalyst （CCC） for Euro Ⅳ stage regulation was investigated through Vehicle Road Running Mode tests, whereas emissions of regulated pollu...The durability of three-way catalyst （TWC） and corresponding close-coupled catalyst （CCC） for Euro Ⅳ stage regulation was investigated through Vehicle Road Running Mode tests, whereas emissions of regulated pollutants of three car fleet were investigated at every 100,000 km miles. The results showed that HC, NOx, and CO emission values could meet Euro Ⅳ regulation limits at every point. The redox properties of TWC and CCC were measured by CO reduction during each isothermal. It was obvious that both aged TWC and aged CCC behaved a good redox property at 673 and 773 K. Based on XRD and BET measurement results, TWC and CCC washcoat were characterized with good thermal stability.展开更多
A series of Pt-Pd bimetallic catalysts supported on CeO_(2)-ZrO_(2)-La_(2)O_(3) mixed oxides were synthesized through the conventional impregnation method.Three-way catalytic performance evaluations along with detaile...A series of Pt-Pd bimetallic catalysts supported on CeO_(2)-ZrO_(2)-La_(2)O_(3) mixed oxides were synthesized through the conventional impregnation method.Three-way catalytic performance evaluations along with detailed physio-chemical characterizations were carried out to establish possible structure-activity correlations.Results show that on the one hand,different Pt/Pd ratios can strongly affect the TWC behaviors of Pt-Pd/CZL catalysts by modulating the synergistic effect between Pt and Pd.On the other hand,higher Pt/Pd ratio also favors better dispersion of precious metals.Such improved precious metals(PM)dispersion can promote the metal-support interaction and increase the surface oxygen vacancies concentration,thereby raising the dynamic oxygen storage/release capacity,improving the redox ability as well as enha ncing the thermal stability of the Pt-Pd/CZL catalyst.Moreover,the stro ng metal-support interaction can augment surface oxygen vacancy concentration,thereby benefiting low temperature CO and NO reaction via augmented NOxadsorption and nitrate conversion.展开更多
The next-generation Euro 7 standard proposed much lower pollutant limits from gasoline vehicles,specifically for CO and NO_(x),which would be challenging for the three-way catalysts(TWCs)utilized commercially to elimi...The next-generation Euro 7 standard proposed much lower pollutant limits from gasoline vehicles,specifically for CO and NO_(x),which would be challenging for the three-way catalysts(TWCs)utilized commercially to eliminate these pollutants.TWCs with reductive(Rh)and oxidative(Pd)active components on gasoline particulate filters(TWC on GPF)play importantly auxiliary roles in the remediation of CO and NO_(x)downstream the close coupled TWCs to meet their emission targets.Here,a low-content Rh-based TWC(0.17 wt%)zoned with a less expensive Pd-based TWC(0.29 wt%)for GPF applications(cGPF)is reported using improved colloidal deposition method.The supporting of Rh on Y-stabilized ZrO_(2)rather than on CeO_(2)-ZrO_(2)inhibits the formation of inactive Ce rhodate species,while Pd on CeO_(2)-ZrO_(2)not only guarantees the high oxygen storage capacity(OSC)but also enhances catalytic activity.The layout of the front one-fifth in volume being 0.29 wt%Pd on Ce_(0.43)Zr_(0.5)7O_(2)and the rear four-fifths being 0.17 wt%Rh on Zr_(0.85)Y_(0.15)O_(2)prevents the possible alloying of Rh with Pd.The highly effective zoned Rh and Pd TWCs show synergistic three-way activity before and after severe hydrothermal aging at 1000℃with 10%water for24 h,which could be potential choices for close coupled GPF application to satisfy the upcoming stringent emission standards,such as Euro 7 and China 6b.展开更多
In this paper a low-density pairwise check(LDPC) coded three-way relay system is considered, where three user nodes desire to exchange messages with the help of one relay node. Since physical-layer network coding is a...In this paper a low-density pairwise check(LDPC) coded three-way relay system is considered, where three user nodes desire to exchange messages with the help of one relay node. Since physical-layer network coding is applied, two time slots are sufficient for one round information exchange. In this paper, we present a decode-and-forward(DF) scheme based on joint LDPC decoding for three-way relay channels, where relay decoder partially decodes the network code rather than fully decodes all the user messages. Simulation results show that the new DF scheme considerably outperforms other common schemes in three-way relay fading channels.展开更多
Operating principle of water three-way valve with high flow for individual hydraulic prop in coal was presented in this paper, its strict and precise mathematical model was established, its flow field was simulated nu...Operating principle of water three-way valve with high flow for individual hydraulic prop in coal was presented in this paper, its strict and precise mathematical model was established, its flow field was simulated numerically by software Fluent, and its dynamic characteristics were analyzed during the work process such as raising leg, loading and overflow, the influence of the related parameters on high-flow water three-way valve was determined. The results as follows： during the raising leg stage and early raising leg stage, when the damping ratio increases, the overshoot of system decreases and the setting time reduces, and the dynamic response performance has a significant improvement. During the loading stage and the overflow stage, the pressure in plunger chamber of single hydraulic prop, the output flow and the displacement of the high-flow water three-way valve decrease with the decreasing of the external load. The spring stiffness of the safety valve directs the flow and the spool＇s displacement of the safety valve, and it can be used to control the high-flow three-way valve＇s sensitivity.展开更多
基金supported by the financial aid from National Science and Technology Major Project of China(No.2020YFE0204500)National Natural Science Foundation of China(Nos.22020102003,22025506 and 11975301)Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2020286)。
文摘The three-way catalyst(TWC),as a promising approach to control automobile exhaust emission,has been widely studied and applied.However,it still suffers from the high light-off temperature and poor stability.Herein,we synthesized a multicomponent catalyst Rh/Cu-CeSn by using Cu metal doping to modify the Ce-based solid solution,which exhibited good TWC catalytic performance:the light-off temperatures for CO,NO,and C_(3)H_(6)conversion are 172℃,266℃,and 193℃,respectively.Moreover,the catalyst still maintained good activity after 12 h of the continuous reaction under high-temperature conditions.The experiments and mechanism studies reveal that due to the redox pair Cu^(+)/Cu^(2+),the Cu incorporation can effectively inhibit the Rh transition to the oxidation state and greatly enhance the catalytic activity and stability.This work provides a viable strategy for precise characteristic modulation of composite oxide supports during the fabrication of noble metal-based catalysts,which significantly reduces environmental pollution from energy applications.
基金Central University Basic Research Fund of China,Grant/Award Number:FWNX04Ningxia Natural Science Foundation,Grant/Award Number:2021AAC03203National Natural Science Foundation of China,Grant/Award Number:61662001。
文摘Three-way concept analysis is an important tool for information processing,and rule acquisition is one of the research hotspots of three-way concept analysis.However,compared with three-way concept lattices,three-way semi-concept lattices have three-way operators with weaker constraints,which can generate more concepts.In this article,the problem of rule acquisition for three-way semi-concept lattices is discussed in general.The authors construct the finer relation of three-way semi-concept lattices,and propose a method of rule acquisition for three-way semi-concept lattices.The authors also discuss the set of decision rules and the relationships of decision rules among object-induced three-way semi-concept lattices,object-induced three-way concept lattices,classical concept lattices and semi-concept lattices.Finally,examples are provided to illustrate the validity of our conclusions.
基金supported by the financial aid from National Science and Technology Major Project of China(2021YFB3500700)National Natural Science Foundation of China(22020102003,22025506,22271274 and U23A20140)Program of Science and Technology Development Plan of Jilin Province of China(20230101035JC and 20230101022JC).
文摘Three-way catalysts are widely used to control criterion pollutant emissions fromthe increasing gasoline engines.With the stringent requirements of automotivepollutant emission standards in various countries,Rh has become an irreplaceablecomponent of three-way catalysts due to its superior NOx elimination,high N2selectivity,and simultaneous elimination of CO and hydrocarbons.In this review,we systematically review the recent development of Rh-based three-way catalystsin terms of potential supports and effective active center construction strategies.We further summarize the key role of Rh metal in the three-way catalytic mechanismand reaction kinetics.Finally,we conclude the current challenges and futureopportunities facing Rh-based catalysts.It is believed that based on the deep understandingof Rh-based three-way catalysts,the design of Rh-based catalysts withgood low-temperature catalytic performance and low cost is expected to be realizedin the future.
基金Supported by the National Natural Science of China (Grant Nos. 1152616361473181)+2 种基金the Research Fund of School of Economic, Northwest University of Political Science and Law (Grant No. 19XYKY02)the Youth Academic Innovation Team in Northwest University of Political Science and Lawthe Young Academic Backbone of Chang’an in Northwest University of Political Science and Law
文摘In this paper, we propose three-way granular approximations(3WGAs) based on bisimulations. We discover the relationships between 3WGAs based on underlying relations and 3WGAs based on bisimilarity(the largest bisimulation induced by an underlying relation).
基金Project supported by National High-Tech Research and Development Program of China (2011AA03A405)the Key Program of Tianjin Natural Science Foundation (09JCZDJC26600)
文摘The effect of Co doping on ceria-zirconia mixed oxides was investigated for Co0.1Ce0.6Zr0.3Ox sample prepared by sol-gel method. The Pd-only three-way catalyst （TWC） was obtained by incipient wetness impregnation with 0.5 wt.% Pd loading. The structural and oxygen handling properties were analyzed by X-ray diffraction （XRD）, H2-temperature programmed reduction （H2-TPR） and the dynamic oxygen storage capacity （DOSC）. The introduction of Co into ceria-zirconia lattice strongly modified the mobility of oxygen and enhanced the DOSC performance. Pd-only TWC based on the Co0.1Ce0.6Zr0.3Ox support exhibited superior activity for water-gas shift and steam reforming and ampli- fied amplitude of stoichiometric window.
基金Project supported by National Natural Science Foundation of China (20773090, 20803049)the Specialized Research Fund for the Doctoral Program of Higher Education (20070610026, 200806100009)
文摘Ce-Zr-Al-Nd2O3 （CZAN） support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffTaction （XRD）, low temperature nitrogen adsorption-desorption, oxygen pulsing technique, H2-temperamre programmed reduction （H2-TPR） and X-ray photoelectron spectroscopy （XPS）. The Pd-only three-way catalysts （Pd-TWC） supported on these materials were prepared by incipient wetness method and studied by activity tests. The results demonstrated that the CZAN supports obtained by the two methods showed better structural, textural and redox properties than the CZA without Nd2O3, and the addition of Nd203 improved the catalytic activity of TWC. Especially, the CZAN-i support prepared by impregnation method had better thermal stability and redox property. Meanwhile, the Pd/CZAN-i catalyst exhibited the best catalytic performance. XPS measurements indicated that the Nd-modified samples possessed more Ce3＋ and oxygen vacancies on the surface of samples, which led to a better redox property. The excellent redox property of support materials helped to improve the catalytic activity of TWC.
基金The National Natural Science Foundation of China(No.71171048,71371049)the Scientific Innovation Research of College Graduates in Jiangsu Province(No.KYLX15-0190)the Scientific Research Foundation of Graduate School of Southeast University(No.YBJJ1567)
文摘Based on linguistic evaluations, a linguistic threeway decision method is proposed. First, the alternatives are rated in linguistic forms and divided into acceptance, rejection and uncertainty regions. Secondly, the linguistic three-way group decision steps are provided. Specifically, the experts determine the lower bound and upper bound of the uncertainty region, respectively. When the evaluation is superior to the upper bound, the corresponding alternative is put into the acceptance region directly. Similarly, when the evaluation is inferior to the lower bound, the corresponding alternative is put into the rejection region directly, and the remaining alternatives are put into the uncertain region. Moreover, the objects in the uncertainty region are especially discussed. The linguistic terms are transformed into fuzzy numbers and then aggregated. Finally, a recommendation example is provided to illustrate the practicality and validity of the proposed method.
基金supported by the National High-Tech Research and Development Program of China(2009AA064803)
文摘In the purification process of automobile exhaust,existing water plays an important role as an oxidant,which converts CO and hydrocarbons（HCs） by the water-gas shift（WGS） and the steam reforming（SR） reactions,respectively,especially at high temperatures.Meanwhile it is major component of the exhaust which can affect significantly the thermal stability of the three-way catalyst.Activity experiments were carried out close to the real operation conditions（GHSV,concentration,etc.） with a Pd/Ce0.67Zr0.33O2 catalyst supplying information on the CO and C3H8 oxidation reactions in feedstream formed by different reactant combinations.The obtained results showed that the activity of the CO and C3H8 oxidation was promoted by the addition of steam due to the WGS and SR reactions.The WGS and SR reaction were competitive under oxygen-lean conditions.The kinetic analysis was considered for WGS and SR reactions.
文摘Three-way pipes, T and Y pipes, are very important connecting components in pipeline systems, their strength are related to the safety of pipelines. In the case that crack is not detected in the three-way pipe, ANSYS finite element program version 5.6 is applied to study the stress distribution of the three-way pipe and to obtain the optimum fillet radius in the crotch region of the two pipes. The reasonable intersection angle of the two pipes is also obtained. In the case that a surface crack is detected in the three-way pipe, the maximum stress intensity factor (SIF) near the front of the surface crack is studied.
基金support the National HighTech Research and Development Program of China (No.2011AA03A405)
文摘FeOx-CeO2 mixed oxides with increasing Fe/（Ce＋Fe） atomic ratio （1-20 mol%） were prepared by sol-gel method and characterized by X-ray powder diffraction （XRD）, Brunauer-Emrnett-Teller （BET） and Hydrogen temperature-programmed reduction （H2-TPR） techniques. The dynamic oxygen storage capacity （DOSC） was investigated by mass spectrometry with CO/O2 transient pulses. The powder XRD data following Rietveld refinement revealed that the solubility limit of iron oxides in the CeO2 was 5 mol% based on Fe/（Ce＋Fe）. The lattice parameters experienced a decrease followed by an increase due to the influence of the maximum solubility limit of iron oxides in the CeO2. TPR analysis revealed that Fe introduction into ceria strongly modified the textual and structural properties, which influenced the oxygen handling properties. DOSC results revealed that Ce-based materials containing Fe oxides with multiple valences contribute to the majority of DOSC. The kinetic analysis indicated that the calculated apparent kinetic parameters obey the compensation effect. The three-way catalytic performance for Pd-only catalysts based on the Fe doping support exhibited the redundant iron species separated out of the CeO2 and interacted with the ceria and Pd species on the surface, which seriously influenced the catalytic properties, especially after hydrothermal aging treatment.
基金the Aeronautical Science Foundation of China(2017ZC53021)the Open Project Fund of CETC Key Laboratory of Data Link Technology(CLDL-20182101).
文摘Real-time resource allocation is crucial for phased array radar to undertake multi-task with limited resources,such as the situation of multi-target tracking,in which targets need to be prioritized so that resources can be allocated accordingly and effectively.A three-way decision-based model is proposed for adaptive scheduling of phased radar dwell time.Using the model,the threat posed by a target is measured by an evaluation function,and therefore,a target is assigned to one of the three possible decision regions,i.e.,positive region,negative region,and boundary region.A different region has a various priority in terms of resource demand,and as such,a different radar resource allocation decision is applied to each region to satisfy different tracking accuracies of multi-target.In addition,the dwell time scheduling model can be further optimized by implementing a strategy for determining a proper threshold of three-way decision making to optimize the thresholds adaptively in real-time.The advantages and the performance of the proposed model have been verified by experimental simulations with comparison to the traditional twoway decision model and the three-way decision model without threshold optimization.The experiential results demonstrate that the performance of the proposed model has a certain advantage in detecting high threat targets.
基金Project supported by the Beijing Nova Program(Z181100006218030)Major State Research Development Program of Hebei province(20374202D)。
文摘As the oxygen redox ability shows great effects on the catalytic performances of ceria-zirconia based materials,many strategies have been utilized to improve the oxygen storage capacity.Here in this study,we report a simple and facile approach to prepare a SO_(4)^(2-)-modified La,Y-doped ceria-zirconia material(SO/CZLY-f)with high oxygen storage capacity.Due to the additional redox process between SO_(4)^(2-)and S^(2-),oxygen storage capacity of SO/CZLY-f(745.3μmol O_(2)/g)is about 1.6 times higher than that of La,Ydoped ceria-zirconia material without SO_(4)^(2-)modification.Moreover,the catalytic activities and stability of the corresponding Pd-only three-way catalyst were measured.Compared to that of Pd@CZLY-f,the operation window of CO,full conversion temperature of HC and NO over Pd@SO/CZLY-f are obviously widened and lowered,respectively.After aging treatment at 1100℃for 4 h,the superiority of aged Pdloading composite is still maintained.
基金Project supported by National High-Tech Research and Development Program of China(2011AA03A405)the Key Program of TianjinNatural Science Foundation(09JCZDJC26600)
文摘Ceria-zirconia-alumina （CZA） solid solution was prepared by sol-gel method in the present study. 0.5 wt.% Pd supported on CZA was prepared by incipient wetness impregnation. The steam effects for CO and C3H8 oxidation, three-way catalytic activity and stoichiometric window property were studied. The light-off temperature of the CO oxidation reaction shifted to a lower temperature due to the water-gas shift （WGS） reactions. The oxidation of C3H8 was enhanced due to the steam reforming （SR） reactions. The steam promoted the C3H8 oxidation and NO reduction in three-way catalytic reaction. The amplitude of stoichiometric window was amplified by the addition of water to the feed stream.
基金supported in part by the National Natural Science Foundation of China(12271146,12161036,61866011,11961025,61976120)the Natural Science Key Foundation of Jiangsu Education Department(21KJA510004)Discovery Grant from Natural Science and Engineering Research Council of Canada(NSERC)。
文摘Three-way decision(T-WD)theory is about thinking,problem solving,and computing in threes.Behavioral decision making(BDM)focuses on effective,cognitive,and social processes employed by humans for choosing the optimal object,of which prospect theory and regret theory are two widely used tools.The hesitant fuzzy set(HFS)captures a series of uncertainties when it is difficult to specify precise fuzzy membership grades.Guided by the principles of three-way decisions as thinking in threes and integrating these three topics together,this paper reviews and examines advances in three-way behavioral decision making(TW-BDM)with hesitant fuzzy information systems(HFIS)from the perspective of the past,present,and future.First,we provide a brief historical account of the three topics and present basic formulations.Second,we summarize the latest development trends and examine a number of basic issues,such as one-sidedness of reference points and subjective randomness for result values,and then report the results of a comparative analysis of existing methods.Finally,we point out key challenges and future research directions.
文摘Oxygen storage-capacity （OSC）, oxygen buffer capacity （OBC）, X-my diffraction and electron diffraction pattern, high resolution electron microscopy were used to study the quaternary oxides, i .e., of Ce, Tb, Pr and Zr. （Ce0.6 Tb0.2Zr0.2O2- δ and Ce0.6Pr0.2Zr0.2O2-δ ）. OSC and OBC data indicate that these oxides have very good oxygen transfer capacity （OTC） and their pseudo-solid solutions exhibit fluorite-type structure. These oxides may act as a good candidate for three-way catalysts （TWC）.
基金supported by the 863 Program (2006AA060305)China Postdoctoral Science Foundation (20070410196)+1 种基金Jiangsu Province Planned Projects for Postdoctoral Research Funds (0702054C)Jiangsu Province Natural Science Fund (BK2008532)
文摘The durability of three-way catalyst （TWC） and corresponding close-coupled catalyst （CCC） for Euro Ⅳ stage regulation was investigated through Vehicle Road Running Mode tests, whereas emissions of regulated pollutants of three car fleet were investigated at every 100,000 km miles. The results showed that HC, NOx, and CO emission values could meet Euro Ⅳ regulation limits at every point. The redox properties of TWC and CCC were measured by CO reduction during each isothermal. It was obvious that both aged TWC and aged CCC behaved a good redox property at 673 and 773 K. Based on XRD and BET measurement results, TWC and CCC washcoat were characterized with good thermal stability.
基金Project supported by the Key Program of Science Technology Department of Zhejiang Province(2018C03037)the Natural Science Foundation of Jiangsu Province(BK20201037)+2 种基金Jiangsu Industry-University-Research Cooperation Project(BY2022101)the Scientific Research Fund of Nanjing Institute of Technology(YKJ2019111)Students'Science and Technology Innovation Fund of Nanjing Institute of Technology(TB202312034).
文摘A series of Pt-Pd bimetallic catalysts supported on CeO_(2)-ZrO_(2)-La_(2)O_(3) mixed oxides were synthesized through the conventional impregnation method.Three-way catalytic performance evaluations along with detailed physio-chemical characterizations were carried out to establish possible structure-activity correlations.Results show that on the one hand,different Pt/Pd ratios can strongly affect the TWC behaviors of Pt-Pd/CZL catalysts by modulating the synergistic effect between Pt and Pd.On the other hand,higher Pt/Pd ratio also favors better dispersion of precious metals.Such improved precious metals(PM)dispersion can promote the metal-support interaction and increase the surface oxygen vacancies concentration,thereby raising the dynamic oxygen storage/release capacity,improving the redox ability as well as enha ncing the thermal stability of the Pt-Pd/CZL catalyst.Moreover,the stro ng metal-support interaction can augment surface oxygen vacancy concentration,thereby benefiting low temperature CO and NO reaction via augmented NOxadsorption and nitrate conversion.
基金Project supported by the National Natural Science Foundation of China(22076062,22276070)China Postdoctoral Science Foundation(2022M711957)+1 种基金National Engineering Laboratory for Mobile Source Emission Control Technology(NELMS2019A14)Project of Jinan Municipal Bureau of Science and Technology(2020GXRC021).
文摘The next-generation Euro 7 standard proposed much lower pollutant limits from gasoline vehicles,specifically for CO and NO_(x),which would be challenging for the three-way catalysts(TWCs)utilized commercially to eliminate these pollutants.TWCs with reductive(Rh)and oxidative(Pd)active components on gasoline particulate filters(TWC on GPF)play importantly auxiliary roles in the remediation of CO and NO_(x)downstream the close coupled TWCs to meet their emission targets.Here,a low-content Rh-based TWC(0.17 wt%)zoned with a less expensive Pd-based TWC(0.29 wt%)for GPF applications(cGPF)is reported using improved colloidal deposition method.The supporting of Rh on Y-stabilized ZrO_(2)rather than on CeO_(2)-ZrO_(2)inhibits the formation of inactive Ce rhodate species,while Pd on CeO_(2)-ZrO_(2)not only guarantees the high oxygen storage capacity(OSC)but also enhances catalytic activity.The layout of the front one-fifth in volume being 0.29 wt%Pd on Ce_(0.43)Zr_(0.5)7O_(2)and the rear four-fifths being 0.17 wt%Rh on Zr_(0.85)Y_(0.15)O_(2)prevents the possible alloying of Rh with Pd.The highly effective zoned Rh and Pd TWCs show synergistic three-way activity before and after severe hydrothermal aging at 1000℃with 10%water for24 h,which could be potential choices for close coupled GPF application to satisfy the upcoming stringent emission standards,such as Euro 7 and China 6b.
基金supported in part by the National Natural Science Foundation of China under Grant 61201187by the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions under Grant YETP0110+2 种基金by the Tsinghua University Initiative Scientific Research Program under Grant 20121088074by the Foundation of Zhejiang Educational Committee under Grant Y201121579by the Visiting Scholar Professional Development Project of Zhejiang Educational Committee under Grant FX2014052
文摘In this paper a low-density pairwise check(LDPC) coded three-way relay system is considered, where three user nodes desire to exchange messages with the help of one relay node. Since physical-layer network coding is applied, two time slots are sufficient for one round information exchange. In this paper, we present a decode-and-forward(DF) scheme based on joint LDPC decoding for three-way relay channels, where relay decoder partially decodes the network code rather than fully decodes all the user messages. Simulation results show that the new DF scheme considerably outperforms other common schemes in three-way relay fading channels.
基金Supported by the National Natural Science Foundation of China （51075001） the Nature Science Research Project of Anhui Province （KJ2009A020）
文摘Operating principle of water three-way valve with high flow for individual hydraulic prop in coal was presented in this paper, its strict and precise mathematical model was established, its flow field was simulated numerically by software Fluent, and its dynamic characteristics were analyzed during the work process such as raising leg, loading and overflow, the influence of the related parameters on high-flow water three-way valve was determined. The results as follows： during the raising leg stage and early raising leg stage, when the damping ratio increases, the overshoot of system decreases and the setting time reduces, and the dynamic response performance has a significant improvement. During the loading stage and the overflow stage, the pressure in plunger chamber of single hydraulic prop, the output flow and the displacement of the high-flow water three-way valve decrease with the decreasing of the external load. The spring stiffness of the safety valve directs the flow and the spool＇s displacement of the safety valve, and it can be used to control the high-flow three-way valve＇s sensitivity.
