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Rule acquisition of three-way semi-concept lattices in formal decision context
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作者 Jie Zhao Renxia Wan +1 位作者 Duoqian Miao Boyang Zhang 《CAAI Transactions on Intelligence Technology》 SCIE EI 2024年第2期333-347,共15页
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
关键词 finer relation rule acquisition three-way concept analysis three-way semi-concept lattices
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Three-Way Behavioral Decision Making With Hesitant Fuzzy Information Systems:Survey and Challenges 被引量:2
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作者 Jianming Zhan Jiajia Wang +1 位作者 Weiping Ding Yiyu Yao 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2023年第2期330-350,共21页
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
关键词 Hesitant fuzzy information system(HFIS) prospect theory regret theory three-way decision(T-WD)
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Three-way group decision making with linguistic evaluations
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作者 刘树利 刘新旺 《Journal of Southeast University(English Edition)》 EI CAS 2016年第4期520-523,共4页
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
关键词 linguistic evaluation UNCERTAINTY triangular fuzzy sets three-way group decision making RECOMMENDATION
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An adaptive dwell time scheduling model for phased array radar based on three-way decision 被引量:4
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作者 LI Bo TIAN Linyu +1 位作者 CHEN Daqing LIANG Shiyang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2020年第3期500-509,共10页
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
关键词 phased array radar resource scheduling three-way decision threat assessment
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Stress and Fracture Strength Analysis for Three-Way Pipes 被引量:3
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作者 XU Jing-jing, WU Yi-min School of Electromechanical Engineering and Automation, Shanghai University, Shanghai 200072, China 《Advances in Manufacturing》 SCIE CAS 2000年第S1期11-15,共5页
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
关键词 three-way pipes intersection angle CRACK fracture strength stress intensity factor (SIF) Kscc
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Quaternary Oxide of Cerium, Terbium, Praseodymium and Zirconium for Three-Way Catalysts 被引量:3
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作者 康振晋 康振川 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第3期314-319,共6页
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
关键词 oxygen storage capacity oxygen buffer capacity three-way catalysts rare earths
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Durability of three-way and close-coupled catalysts for Euro IV regulation 被引量:2
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作者 贾莉伟 沈美庆 +3 位作者 王军 王家明 褚霞 顾炜炜 《Journal of Rare Earths》 SCIE EI CAS CSCD 2008年第6期827-830,共4页
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
关键词 three-way catalyst DURABILITY redox property emission control regulations rare earths
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Dynamic characteristics of the high-flow water three-way valve 被引量:2
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作者 Chuan-Li WANG Xia GAO Hai-Shun DENG Yu HUANG 《Journal of Coal Science & Engineering(China)》 2013年第3期392-395,共4页
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
关键词 high-flow three-way valve water hydraulic structural design dynamic characteristics
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A Decode-and-Forward Scheme for LDPC Coded Three-Way Relay Fading Channels 被引量:2
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作者 YE Xia GAO Feifei 《China Communications》 SCIE CSCD 2015年第8期46-54,共9页
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
关键词 three-way relay channel physicallayer network coding LDPC codes decode-and forward
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Influence of Ce_(0.35)Zr_(0.55)Y_(0.10) Solid Solution on Performance of Pt-Rh Three-Way Catalysts 被引量:1
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作者 郭家秀 袁书华 +3 位作者 龚茂初 沈美 钟俊波 陈耀强 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第2期179-183,共5页
Ce0.35Zr0.55Y0. 10 solid solution was prepared by co-precipitation technique and characterized by specific surface area measurements (BET) and X-ray diffraction (XRD). Ce0.35Zr0.55Y0.10 was used to prepare low Pt-... Ce0.35Zr0.55Y0. 10 solid solution was prepared by co-precipitation technique and characterized by specific surface area measurements (BET) and X-ray diffraction (XRD). Ce0.35Zr0.55Y0.10 was used to prepare low Pt-Rh threeway catalyst (TWC), and its influence on the performance of TWC was investigated. The results revealed that Ce0.35 Zr0.55Y0.10 had a cubic structure similar to Ce0.50Zr0.50O2 and its specific surface area can maintain higher than Ce0.50 Zr0.50O2 after 1000 ℃ calcination for 5 h. Being hydrothermal aged at 1000 ℃ for 5 h, the catalyst containing Ce0.35 Zr0.55Y0.10 still exhibited higher conversion of C3H8, CO and NO and lower light-off temperature in comparison with Ce0.50Zr0.50O2 TWC. 展开更多
关键词 low precious metal three-way catalysts rare earths
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Influences of (Ce-Zr-La-Pr)O Contents on Three-Way Catalyst Performances 被引量:1
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作者 张爱敏 宁平 马丽萍 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第S1期65-69,共5页
A series of catalysts with (Ce-Zr-La-Pr)O contents range from 0 to 50% in coating and single-palladium loads on substrates were prepared to study effects of (Ce-Zr-La-Pr)O contents on catalytic activities and durabili... A series of catalysts with (Ce-Zr-La-Pr)O contents range from 0 to 50% in coating and single-palladium loads on substrates were prepared to study effects of (Ce-Zr-La-Pr)O contents on catalytic activities and durability by contrasting the characteristics of light-off, A/F and catalytic conversions of the fresh catalysts with that of the aged catalysts. The results show that (Ce-Zr-La-Pr)O can enhance the catalysts light-off characteristics, widen A/F windows and increase catalytic conversions at a certain extent through optimizing physical structural and chemical property of the mixed coating. However, (Ce-Zr-La-Pr)O contents influence greatly on the catalysts activities and durability, and the catalysts with contents ranging from 10% to 30% exhibited better integrative properties in all samples, and 10% was the optical content to make the catalyst performance highest in this thesis. It is indicated that an suitable content of (Ce-Zr-La-Pr)O plays an important role in assisting catalysis, enhancing durability and increasing oxygen storage capability. 展开更多
关键词 (Ce-Zr-La-Pr)O mixed oxide three-way catalyst catalytic activity durability rare earths
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Regulated and Speciated Hydrocarbon Emissions from a Dual Fuel Light Duty Vehicle with and Without a Three-Way Catalyst 被引量:1
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作者 丁焰 葛蕴珊 +2 位作者 王军方 谭建伟 尤可为 《Journal of Beijing Institute of Technology》 EI CAS 2010年第1期31-36,共6页
The regulated pollutants (CO,HC and NOx) and unregulated pollutants (volatile organic compounds and carbonyl compounds),emitted from a dual fuel vehicle fueled with gasoline and E10 fuel,are measured under a trans... The regulated pollutants (CO,HC and NOx) and unregulated pollutants (volatile organic compounds and carbonyl compounds),emitted from a dual fuel vehicle fueled with gasoline and E10 fuel,are measured under a transient cycle and steady modes.The impacts of a three-way catalyst (TWC) are investigated for the two types of fuels.The measured results show that NOx and acetaldehyde emitted from the E10-fueled car are much more than that from the gasoline-fueled car under the same modes.On the basis of maximum incremental reactivity (MIR) factors and emissions of organic gases,the ozone specific reactivity of the tailpipe gases are evaluated. 展开更多
关键词 regulated emissions volatile organic compounds (VOCs) CARBONYLS three-way catalyst (TWC)
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Energy Optimization Oriented Three-Way Clustering Algorithm for Cloud Tasks 被引量:1
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作者 Chunmao Jiang Yibing Li Zhicong Li 《Journal of Beijing Institute of Technology》 EI CAS 2018年第2期189-197,共9页
Cloud computing has developed as an important information technology paradigm which can provide on-demand services. Meanwhile,its energy consumption problem has attracted a grow-ing attention both from academic and in... Cloud computing has developed as an important information technology paradigm which can provide on-demand services. Meanwhile,its energy consumption problem has attracted a grow-ing attention both from academic and industrial communities. In this paper,from the perspective of cloud tasks,the relationship between cloud tasks and cloud platform energy consumption is established and analyzed on the basis of the multidimensional attributes of cloud tasks. Furthermore,a three-way clustering algorithm of cloud tasks is proposed for saving energy. In the algorithm,f irst,t he cloud tasks are classified into three categories according to the content properties of the cloud tasks and resources respectively. Next,cloud tasks and cloud resources are clustered according to their computation characteristics( e. g. computation-intensive,data-intensive). Subsequently,greedy scheduling is performed. The simulation results showthat the proposed algorithm can significantly reduce the energy cost and improve resources utilization,compared with the general greedy scheduling algorithm. 展开更多
关键词 cloud computing cloud energy three-way cluster task attributes
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INVESTIGATION ON THE DYNAMIC RESPONSE PERFORMANCE OF A NOVEL THREE-WAY SOLENOID VALVE
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作者 李维 苏岭 +2 位作者 汪映 周龙保 柳泉冰 《Journal of Pharmaceutical Analysis》 SCIE CAS 2006年第1期13-16,20,共5页
Objective A novel high-speed three-way solenoid valve is developed, which is used for the common-rail injection system equipped on DME powered engine. In order to improve the dynamic response performance of the three-... Objective A novel high-speed three-way solenoid valve is developed, which is used for the common-rail injection system equipped on DME powered engine. In order to improve the dynamic response performance of the three-way solenoid. Methods Experimental studies have been conducted to investigate the effects of spool stroke, drive voltage, negative demagnetizing pulse and two drive schemes on the dynamic response performance of the three-way solenoid valve. Results The results show that the dynamic response performance of the three-way solenoid valve can be remarkably improved by shortening the spool stroke and increasing the drive voltage. Simultaneously, the difference between the response time of closing valve and that of opening valve decreases. At each different drive voltage, there exists an optimal negative demagnetizing pulse corresponding to the same positive exciting pulse. At this optimal pulse, the dynamic response performance of the three-way solenoid valve is the best. In addition, the high drive voltage can lead to the smaller optimal negative demagnetizing pulse. It is also indicated from the experiments that the dynamic response performance of the three-way solenoid valve is better when the NO.1 drive scheme is adopted. The lower drive voltage results in the larger difference between the dynamic response performances for the two drive schemes. Conclusion The dynamic response performance of a novel three-way solenoid valve is good. 展开更多
关键词 three-way solenoid valve dynamic response performance common-rail
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Effect of Sulfur on the Performance of Three-Way Catalysts
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作者 Li Yang He Zhenfu +2 位作者 Shao Qian Shen Ningyuan Jing Zhenhua(SINOPEC Research Institute of Petroleum Processing, Beijing 100083) 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2003年第3期53-57,共5页
Sulfur content is one of the fuel properties to be monitored. Sulfur dioxide, the major product derived from organic sulfur compounds in the exhaust gas emissions, is a poison to the three-way catalysts (TWC). A gas m... Sulfur content is one of the fuel properties to be monitored. Sulfur dioxide, the major product derived from organic sulfur compounds in the exhaust gas emissions, is a poison to the three-way catalysts (TWC). A gas mixture was applied to simulate the exhaust gases used in the TWC aging procedure tests. Two types of the TWC, REX-IIC and REX-IID, were tested in this study. The performance of both TWC's before and after the 100-hour sulfur aging program was compared. It was concluded that the Pt component in the TWC was apt to be poisoned by sulfur much easily than Rh. The performance of the REX-IID catalyst was generally better than that of the REX-IIC catalyst. 展开更多
关键词 three-way catalyst simulated aging performance tests
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Fattening Effects of Two Kinds of Three-way Crossbreeding Commercial Pigs
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作者 Guo Tong Gao Wei +4 位作者 Wu Yan Li Xiaochen Dong Qing Wang Yuan Li Yazhu 《Animal Husbandry and Feed Science》 CAS 2017年第3期138-139,共2页
To understand the fattening performance of Duroc x Landrace×Yorkshire and Duroc×Yorkshire x landrace, 48 individuals of two kinds of three-way crossbreeding lean type commercial pigs were selected to determi... To understand the fattening performance of Duroc x Landrace×Yorkshire and Duroc×Yorkshire x landrace, 48 individuals of two kinds of three-way crossbreeding lean type commercial pigs were selected to determine average daily feed intake, average daily gain and feed gain ratio. The backtat thickness and eye muscle area of pigs were measured at the end of trial. The results showed that Duroc × Landraee × Yorkshire and Dttroc × Yorkshire x Landrace had similar fattening performance, and could be applied under scientific management conditions. The study is of great significance for development of pig industry. 展开更多
关键词 three-way crossbreeding Fattening performance Duroc × Landrace×Yorkshire Duroc x Yorkshire × Landrace PIGS
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Anti-Robinson Structures for Analyzing Three-Way Two-Mode Proximity Data
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作者 Hans-Friedrich Kohn 《Applied Mathematics》 2014年第6期983-1003,共21页
Multiple discrete (non-spatial) and continuous (spatial) structures can be fitted to a proximity matrix to increase the information extracted about the relations among the row and column objects vis-à-vis a repre... Multiple discrete (non-spatial) and continuous (spatial) structures can be fitted to a proximity matrix to increase the information extracted about the relations among the row and column objects vis-à-vis a representation featuring only a single structure. However, using multiple discrete and continuous structures often leads to ambiguous results that make it difficult to determine the most faithful representation of the proximity matrix in question. We propose to resolve this dilemma by using a nonmetric analogue of spectral matrix decomposition, namely, the decomposition of the proximity matrix into a sum of equally-sized matrices, restricted only to display an order-constrained patterning, the anti-Robinson (AR) form. Each AR matrix captures a unique amount of the total variability of the original data. As our ultimate goal, we seek to extract a small number of matrices in AR form such that their sum allows for a parsimonious, but faithful reconstruction of the total variability among the original proximity entries. Subsequently, the AR matrices are treated as separate proximity matrices. Their specific patterning lends them immediately to the representation by a single (discrete non-spatial) ultrametric cluster dendrogram and a single (continuous spatial) unidimensional scale. Because both models refer to the same data base and involve the same number of parameters, estimated through least-squares, a direct comparison of their differential fit is legitimate. Thus, one can readily determine whether the amount of variability associated which each AR matrix is most faithfully represented by a discrete or a continuous structure, and which model provides in sum the most appropriate representation of the original proximity matrix. We propose an extension of the order-constrained anti-Robinson decomposition of square-symmetric proximity matrices to the analysis of individual differences of three-way data, with the third way representing individual data sources. An application to judgments of schematic face stimuli illustrates the method. 展开更多
关键词 Anti-Robinson Structure three-way Data Individual Differences ULTRAMETRIC Unidimensional Scale
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A three-way electrolyte with ternary solvents for high-energy-density and long-cycling lithium-sulfur pouch cells
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作者 Zheng Li Legeng Yu +11 位作者 Chen-Xi Bi Xi-Yao Li JinMa Xiang Chen Xue-Qiang Zhang Aibing Chen Haoting Chen Zuoru Zhang Li-Zhen Fan Bo-Quan Li Cheng Tang Qiang Zhang 《SusMat》 SCIE EI 2024年第2期1-12,共12页
Lithium–sulfur(Li–S)batteries promise high-energy-density potential to exceed the commercialized lithiumion batteries but suffer from limited cycling lifespan due to the side reactions between lithium polysulfides(L... Lithium–sulfur(Li–S)batteries promise high-energy-density potential to exceed the commercialized lithiumion batteries but suffer from limited cycling lifespan due to the side reactions between lithium polysulfides(LiPSs)and Li metal anodes.Herein,a three-way electrolyte with ternary solvents is proposed to enable high-energy-density and long-cycling Li–S pouch cells.Concretely,ternary solvents composed of 1,2-dimethoxyethane,di-isopropyl sulfide,and 1,3,5-trioxane are employed to guarantee smooth cathode kinetics,inhibit the parasitic reactions,and construct a robust solid electrolyte interphase,respectively.The cycling lifespan of Li–S coin cells with 50μm Li anodes and 4.0 mg cm^(−2) sulfur cathodes is prolonged from88 to 222 cycles using the three-way electrolyte.Nano-heterogeneous solvation structure of LiPSs and organic-rich solid electrolyte interphase are identified to improve the cycling stability of Li metal anodes.Consequently,a 3.0 Ah-level Li–S pouch cell with the three-way electrolyte realizes a high energy density of 405 Wh kg^(−1) and undergoes 27 cycles.Thiswork affords a three-way electrolyte recipe for suppressing the side reactions of LiPSs and inspires rational electrolyte design for practical high-energy-density and long-cycling Li–S batteries. 展开更多
关键词 lithium metal anodes lithium-sulfur batteries pouch cells solid electrolyte interphase three-way electrolyte
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The structure–activity relationships of Rh/CeO_(2)-ZrO_(2) catalysts based on Rh metal size effect in the three-way catalytic reactions
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作者 Dongming Chen Weixin Zhao +7 位作者 Zihao Xu Zheng Zhao Juanyu Yang Yongke Hou Yongqi Zhang Zongyu Feng Meisheng Cui Xiaowei Huang 《Nano Research》 SCIE EI CSCD 2024年第8期6870-6878,共9页
With the continuous tightening of automotive emission regulations and the increasing promotion of energy-efficient hybrid vehicles,new challenges have arisen for the low-temperature performance of three-way catalysts(... With the continuous tightening of automotive emission regulations and the increasing promotion of energy-efficient hybrid vehicles,new challenges have arisen for the low-temperature performance of three-way catalysts(TWCs).To guide the design of next-generation TWCs,it is essential to further develop our understanding of the relationships between microstructure and catalytic performance.Here,Rh/CeO_(2)–ZrO_(2) catalysts were synthesized with different Rh metal dispersion by using a combination of the wet impregnation method and reduction treatment.These catalysts included Rh single-atom catalysts,cluster catalysts,and nanoparticle catalysts.The results showed that the Rh nanoparticle catalyst,with an average size of 1.9 nm,exhibited superior three-way catalytic performance compared to the other catalysts.Based on the catalytic activity in a series of simple reaction atmospheres such as CO+O_(2),NO+CO,and hydrocarbons(HCs)+O_(2) and operando infrared spectroscopy,we found that metallic Rh sites on Rh nanoparticles are the key factor responsible for the low-temperature catalytic performance. 展开更多
关键词 Rh/CeO_(2)-ZrO_(2) catalyst Rh metal size effect Rh nanoparticles three-way catalytic performance
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方钻杆旋塞阀密封设计 被引量:6
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作者 张继升 董斌 +1 位作者 李悦钦 任晓彬 《钻采工艺》 CAS 北大核心 2007年第5期105-107,共3页
密封性能是方钻杆旋塞阀主要指标之一。密封结构由主阀体孔与上下阀座衬套间的密封、球体与阀座之间的密封、旋钮与阀体旋钮之间的密封三部分组成。高压下,上、下阀座之间的密封仍然是金属对金属之间的密封起作用,但PTFE环的低摩擦系数... 密封性能是方钻杆旋塞阀主要指标之一。密封结构由主阀体孔与上下阀座衬套间的密封、球体与阀座之间的密封、旋钮与阀体旋钮之间的密封三部分组成。高压下,上、下阀座之间的密封仍然是金属对金属之间的密封起作用,但PTFE环的低摩擦系数和减摩作用对减少摩擦力矩有很大作用,容易实现初始接触密封,能加速关闭旋塞阀。文章提出旋塞阀球体与阀座之间的密封,并全面阐述它们的密封机理、密封结构以及材料的选择与强化。 展开更多
关键词 方钻杆旋塞阀 主密封 软密封 密封机理 密封结构
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