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Production of Light Olefins from Biosyngas by Two-stage Catalytic Conversion Process via Dimethyl Ether 被引量:1
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作者 李宇萍 涂军令 +4 位作者 王铁军 马隆龙 张兴华 章青 蔡炽柳 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2014年第2期227-232,I0004,共7页
NiSAPO-34 and NiSAPO-34/HZSM-5 were prepared and evaluated for the performance of dimethyl ether (DME) conversion to light olefins (DTO). The processes of two-stage light olefin production, DME synthesis and the f... NiSAPO-34 and NiSAPO-34/HZSM-5 were prepared and evaluated for the performance of dimethyl ether (DME) conversion to light olefins (DTO). The processes of two-stage light olefin production, DME synthesis and the following DTO, were also investigated using biosyngas as feed gas over Cu/Zn/A1/HZSM-5 and the optimized 2%NiSAPO-34/HZSM- 5. The results indicated that adding 2%Ni to SAPO-34 did not change its topology structure, but resulted in the forming of the moderately strong acidity with decreasing acid amounts, which slightly enhanced DME conversion activity and C2=-C3= selectiw ity. Mechanically mixing 2%NiSAPO-34 with HZSM-5 at the weight ratio of 3.0 further prolonged DME conversion activity to be more than 3 h, which was due to the stable acid sites from HZSM-5. The highest selectivity to light olefins of 90.8% was achieved at 2 h time on stream. The application of the optimized 2%NiSAPO-34/HZSM-5 in the second-stage reactor for DTO reaction showed that the catalytic activity was steady for more than 5 h and light olefin yield was as high as 84.6 g/m3syngas when the biosyngas (H2/CO/CO2/N2/CH4=41.5/26.9/14.2/14.6/2.89, vol%) with low H/C ratio of 1.0 was used as feed gas. 展开更多
关键词 Light olefins two-stage conversion Dimethyl ether Biosyngas NiSAPO-34/HZSM-5
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Multi-objective optimization for leaching process using improved two-stage guide PSO algorithm 被引量:8
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作者 胡广浩 毛志忠 何大阔 《Journal of Central South University》 SCIE EI CAS 2011年第4期1200-1210,共11页
A mathematical mechanism model was proposed for the description and analysis of the heat-stirring-acid leaching process.The model is proved to be effective by experiment.Afterwards,the leaching problem was formulated ... A mathematical mechanism model was proposed for the description and analysis of the heat-stirring-acid leaching process.The model is proved to be effective by experiment.Afterwards,the leaching problem was formulated as a constrained multi-objective optimization problem based on the mechanism model.A two-stage guide multi-objective particle swarm optimization(TSG-MOPSO) algorithm was proposed to solve this optimization problem,which can accelerate the convergence and guarantee the diversity of pareto-optimal front set as well.Computational experiment was conducted to compare the solution by the proposed algorithm with SIGMA-MOPSO by solving the model and with the manual solution in practice.The results indicate that the proposed algorithm shows better performance than SIGMA-MOPSO,and can improve the current manual solutions significantly.The improvements of production time and economic benefit compared with manual solutions are 10.5% and 7.3%,respectively. 展开更多
关键词 leaching process MODELING multi-objective optimization two-stage guide EXPERIMENT
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Cost-effectiveness analysis of population-based screening of hepatocellular carcinoma: Comparing ultrasonography with two-stage screening 被引量:13
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作者 Ming-Jeng Kuo Hsiu-Hsi Chen +8 位作者 Chi-Ling Chen Jean Ching-Yuan Fann Sam Li-Sheng Chen Sherry Yueh-Hsia Chiu Yu-Min Lin Chao-Sheng Liao Hung-Chuen Chang Yueh-Shih Lin Amy Ming-Fang Yen 《World Journal of Gastroenterology》 SCIE CAS 2016年第12期3460-3470,共11页
AIM: To assess the cost-effectiveness of two populationbased hepatocellular carcinoma(HCC) screening programs, two-stage biomarker-ultrasound method and mass screening using abdominal ultrasonography(AUS).METHODS: In ... AIM: To assess the cost-effectiveness of two populationbased hepatocellular carcinoma(HCC) screening programs, two-stage biomarker-ultrasound method and mass screening using abdominal ultrasonography(AUS).METHODS: In this study, we applied a Markov decision model with a societal perspective and a lifetime horizon for the general population-based cohorts in an area with high HCC incidence, such as Taiwan. The accuracy of biomarkers and ultrasonography was estimated from published meta-analyses. The costs of surveillance, diagnosis, and treatment were based on a combination of published literature, Medicare payments, and medical expenditure at the National Taiwan University Hospital. The main outcome measure was cost per lifeyear gained with a 3% annual discount rate. RESULTS: The results show that the mass screening using AUS was associated with an incremental costeffectiveness ratio of USD39825 per life-year gained, whereas two-stage screening was associated with an incremental cost-effectiveness ratio of USD49733 per life-year gained, as compared with no screening. Screening programs with an initial screening age of 50 years old and biennial screening interval were the most cost-effective. These findings were sensitive to the costs of screening tools and the specificity of biomarker screening.CONCLUSION: Mass screening using AUS is more cost effective than two-stage biomarker-ultrasound screening. The most optimal strategy is an initial screening age at 50 years old with a 2-year inter-screening interval. 展开更多
关键词 two-stage biomarker-ultrasound screening One-stage abdominal ultrasonography screening Markov model COST-EFFECTIVENess Sensitivity analysis Age
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Influence of two-stage harvesting on the properties of cold-pressed rapeseed(Brassica napus L.)oils 被引量:5
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作者 NING Ning HU Bing +8 位作者 BAI Chen-yang LI Xiao-hua KUAI Jie HE Han-zi REN Yi-lin WANG Bo JIA Cai-hua ZHOU Guang-sheng ZHAO Si-ming 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第1期265-278,共14页
Rapeseed(Brassica napus L.)harvesting method is critical since it significantly determines the seed yield,oil quality,and industrial efficiency.This study investigated the influences of harvesting methods on the quali... Rapeseed(Brassica napus L.)harvesting method is critical since it significantly determines the seed yield,oil quality,and industrial efficiency.This study investigated the influences of harvesting methods on the quality of cold-pressed rapeseed oil of two varieties.Oil color,peroxide value(POV),tocopherol content,fatty acid composition,and polarity of total polyphenols(PTP)contents of two rapeseed varieties in Huanggang and Xiangyang were compared through artificially simulated combined harvesting and two-stage harvesting.Results showed significant differences in the quality of rapeseed oil between the two harvesting methods.The red value(R-value),POV,total tocopherol contents,linoleic and linolenic acid content,and PTP content of the pressed rapeseed oil prepared by the combined harvesting method were about 27.6,5.7,15.8,2.0,0.5,and 28.6%lower than those of the oil produced from the two-stage harvesting method,respectively.Xiangyang and Huayouza62 performed better in the two regions and two varieties,respectively.To sum up,the rapeseed oil obtained 41–44 days after final flowering of combined harvesting,35 days after final flowering,and six days of post-ripening of the two-stage harvesting had the best quality. 展开更多
关键词 RAPESEED two-stage harvesting combined harvesting oil quality
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Process intensification of fine coal separation using two-stage flotation column 被引量:3
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作者 桂夏辉 刘炯天 +3 位作者 曹亦俊 程敢 张海军 王永田 《Journal of Central South University》 SCIE EI CAS 2013年第12期3648-3659,共12页
Flotation column is widely used as the separation equipment for fine mineral due to its high selectivity. However, this device may be unsuitable for the coarse particle flotation and has high handling ability. A two-s... Flotation column is widely used as the separation equipment for fine mineral due to its high selectivity. However, this device may be unsuitable for the coarse particle flotation and has high handling ability. A two-stage flotation column with dimensions of 2 000 mm×1 000 mm×4 000 mm was designed to enhance the column flotation process. The energy input was modified by adjusting the flow rate and the head of circulating pump. The flotation column was designed with low energy input in the first stage(speed flotation stage) to recover easy-to-float materials quickly, and high energy input in the second stage(recovery stage) to recover difficult-to-float minerals compulsorily. Contrast experiments on the throughput and coarse coal recovery of high ash coal from the Kailuan Mine were conducted using conventional single-stage flotation column and the two-stage flotation column. The results show that the combustible matter recovery of the two-stage flotation column is 5.25% higher than that of the conventional single-stage flotation column. However, the ash contents of clean coal for both columns are similar. Less coarse coals with low ash are obtained using the two-stage flotation column than that using the single-stage column flotation with the same handling ability. The two-stage flotation column process can enhance coal flotation compared with the conventional single-stage column flotation. 展开更多
关键词 flotation column COAL energy input handling ability two-stage flotation
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Use of two-stage dough mixing process in improving water distribution of dough and qualities of bread made from wheat–potato flour 被引量:4
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作者 YIN Jian CHENG Li +4 位作者 HONG Yan LI Zhao-feng LI Cai-ming BAN Xiao-feng GU Zheng-biao 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2021年第1期300-310,共11页
The two-stage dough mixing process was innovated to improve the qualities of bread made from potato flour(PF) and wheat flour at a ratio of 1:1(w/w). The final dough was first prepared from wheat flour before being ad... The two-stage dough mixing process was innovated to improve the qualities of bread made from potato flour(PF) and wheat flour at a ratio of 1:1(w/w). The final dough was first prepared from wheat flour before being added with PF. The effects of the method on enhancing the dough qualities were verified, and the distribution of water in gluten-gelatinized starch matrix of the doughs was investigated. We observed that the bread qualities were improved, as reflected by the increase of specific volume from 2.26 to 2.96 m L g^–1 and the decrease of crumb hardness from 417.93 to 255.57 g. The results from rheofermentometric measurements showed that the dough mixed using the developed mixing method had higher maximum dough height value, time of dough porosity appearance, and gas retention coefficient, as well as enhanced gluten matrix formation compared to that mixed by the traditional mixing method. The results from low-field nuclear magnetic resonance confirmed that the competitive water absorption between gluten and gelatinized starch could restrict the formation of gluten network in the dough mixed using the traditional mixing process. Using the novel mixing method, gluten could be sufficiently hydrated in stage 1, which could then weaken the competitive water absorption caused by gelatinized starch in stage 2;this could also be indicated by the greater mobility of proton in PF and better development of gluten network during mixing. 展开更多
关键词 gelatinized starch gluten network potato flour water distribution two-stage dough mixing process
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Configuration Consideration for Expander in Transcritical Carbon Dioxide Two-Stage Compression Cycle 被引量:3
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作者 马一太 杨俊兰 +1 位作者 管海清 李敏霞 《Transactions of Tianjin University》 EI CAS 2005年第1期53-58,共6页
To investigate the configuration consideration of expander in transcritical carbon dioxide two-stage compression cycle, the best place in the cycle should be searched for to reinvest the recovery work so as to improve... To investigate the configuration consideration of expander in transcritical carbon dioxide two-stage compression cycle, the best place in the cycle should be searched for to reinvest the recovery work so as to improve the system efficiency. The expander and the compressor are connected to the same shaft and integrated into one unit, with the latter being driven by the former, thus the transfer loss and leakage loss can be decreased greatly. In these systems, the expander can be either connected with the first stage compressor (shortened as DCDL cycle) or the second stage compressor (shortened as DCDH cycle), but the two configuration ways can get different performances. By setting up theoretical model for two kinds of expander configuration ways in the transcritical carbon dioxide two-stage compression cycle, the first and the second laws of thermodynamics are used to analyze the coefficient of performance, exergy efficiency, inter-stage pressure, discharge temperature and exergy losses of each component for the two cycles. From the model results, the performance of DCDH cycle is better than that of DCDL cycle. The analysis results are indispensable to providing a theoretical basis for practical design and operating. 展开更多
关键词 carbon dioxide transcritical cycle two-stage compression EXPANDER thermodynamic (analysis)
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An Integrated Process of a Two-Stage Fixed Bed Syngas Production and F-T Synthesis for GTL in Remote Gas Field 被引量:2
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作者 代小平 余长春 +3 位作者 李强 张长斌 江启滢 沈师孔 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第1期85-89,共5页
A novel process for catalytic oxidation of methane to synthesis gas (syngas), which consists of two consecutive fixed-bed reactors with air introduced into the reactors, integrated Fischer-Tropsch synthesis, was inves... A novel process for catalytic oxidation of methane to synthesis gas (syngas), which consists of two consecutive fixed-bed reactors with air introduced into the reactors, integrated Fischer-Tropsch synthesis, was investigated. At the same time, a catalytic combustion technology has been investigated for utilizing the F-T offgas to generate heat or power energy. The results show that the two-stage fixed reactor process keep away from explosion of CH4/O2. The integrated process is fitted to produce diesel oil and lubricating oil in remote gas field. 展开更多
关键词 two-stage fixed reactor SYNGAS Fischer-Tropsch synthesis gas to liquid process
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Two-stage treatment process of pickling wastewater in the cold-rolling production of stainless steel 被引量:3
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作者 SHI Lei CHEN Ronghuan WANG Ruyi 《Baosteel Technical Research》 CAS 2010年第2期16-22,共7页
Based on the characteristics of pickling wastewater in the cold-rolling production of stainless steel, a new processing route, featuring source sludge reduction, wastewater two-stage treatment, heavy metal-contained s... Based on the characteristics of pickling wastewater in the cold-rolling production of stainless steel, a new processing route, featuring source sludge reduction, wastewater two-stage treatment, heavy metal-contained sludge and calcium salt sludge separating recovery, was proposed. As shown by the research results, after the two-stage process treatment, the effluent water can steadily reach the emission standards, the sludge yield can be decreased by more than 8% ; within the heavy metal-contained sludge, the recovery rates of Fc,Cr and Ni can either reach or surpass 95% ,and the total content ofF and S can drop to around 3%. Therefore,the sludge in the front part can be used as ferric dust. In the calcium salt sludge ,the recovery rate of F can either reach or surpass 85% ,and the total contents of Fe,Cr and Ni can fall below 0.5%. So the sludge in the rear part can be used as fluorgypsum or fluorite. Meanwhile,the results of the analysis on heavy metals leaching toxicity and morphologic distribution indicate that the two kinds of sectionalized sludge are not classified as hazardous wastes, which have a stable behavior and better utilization values compared with the former mixed- sludge. 展开更多
关键词 cold-rolled pickling wastewater two-stage process heavy metal-contained sludge calcium salt sludge
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Two-Stage Optimal Scheduling of Community Integrated Energy System
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作者 Ming Li Rifucairen Fu +4 位作者 Tuerhong Yaxiaer Yunping Zheng Abiao Huang Ronghui Liu Shunfu Lin 《Energy Engineering》 EI 2024年第2期405-424,共20页
From the perspective of a community energy operator,a two-stage optimal scheduling model of a community integrated energy system is proposed by integrating information on controllable loads.The day-ahead scheduling an... From the perspective of a community energy operator,a two-stage optimal scheduling model of a community integrated energy system is proposed by integrating information on controllable loads.The day-ahead scheduling analyzes whether various controllable loads participate in the optimization and investigates the impact of their responses on the operating economy of the community integrated energy system(IES)before and after;the intra-day scheduling proposes a two-stage rolling optimization model based on the day-ahead scheduling scheme,taking into account the fluctuation of wind turbine output and load within a short period of time and according to the different response rates of heat and cooling power,and solves the adjusted output of each controllable device.The simulation results show that the optimal scheduling of controllable loads effectively reduces the comprehensive operating costs of community IES;the two-stage optimal scheduling model can meet the energy demand of customers while effectively and timely suppressing the random fluctuations on both sides of the source and load during the intra-day stage,realizing the economic and smooth operation of IES. 展开更多
关键词 Integrated energy system two-stage optimal scheduling controllable loads rolling optimization
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Solar-assisted two-stage catalytic membrane reactor for coupling CO_(2) splitting with methane oxidation reaction
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作者 Jinkun Tan Zhenbin Gu +4 位作者 Zhengkun Liu Pei Wang Reinout Meijboom Guangru Zhang Wanqin Jin 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第11期1771-1780,共10页
A two-stage catalytic membrane reactor(CMR)that couples CO_(2) splitting with methane oxidation reactions was constructed based on an oxygen-permeable perovskite asymmetric membrane.The asymmetric membrane comprises a... A two-stage catalytic membrane reactor(CMR)that couples CO_(2) splitting with methane oxidation reactions was constructed based on an oxygen-permeable perovskite asymmetric membrane.The asymmetric membrane comprises a dense SrFe_(0.9)Ta_(0.1)O_(3-σ)(SFT)separation layer and a porous Sr_(0.9)(Fe_(0.9)Ta_(0.1))_(0.9)Cu_(0.1)O_(3-σ)(SFTC)catalytic layer.In thefirst stage reactor,a CO_(2) splitting reaction(CDS:2CO_(2)→2CO+O_(2))occurs at the SFTC catalytic layer.Subsequently,the O_(2) product is selectively extracted through the SFT separation layer to the permeated side for the methane combustion reaction(MCR),which provides an extremely low oxygen partial pressure to enhance the oxygen extraction.In the second stage,a Sr_(0.9)(Fe_(0.9)Ta_(0.1))_(0.9)Ni_(0.1)O_(3-σ)(SFTN)catalyst is employed to reform the products derived from MCR.The two-stage CMR design results in a remarkable 35.4%CO_(2) conversion for CDS at 900℃.The two-stage CMR was extended to a hollowfiber configuration combining with solar irradiation.The solar-assisted two-stage CMR can operate stably for over 50 h with a high hydrogen yield of 18.1 mL min^(-1) cm^(-2).These results provide a novel strategy for reducing CO_(2) emissions,suggesting potential avenues for the design of the high-performance CMRs and catalysts based on perovskite oxides in the future. 展开更多
关键词 CO_(2)splitting two-stage catalytic membrane reactor Perovskite oxide Asymmetric membrane Solar irradiation assisted
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Design and experiment of high-productivity two-stage vacuum pressure swing adsorption process for carbon capturing from dry flue gas 被引量:2
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作者 Xiuxin Yu Bing Liu +1 位作者 Yuanhui Shen Donghui Zhang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2022年第3期378-391,共14页
A two-stage vacuum pressure swing adsorption(VPSA)process that coupled kinetically controlled and equilibrium controlled separation process with reflux has been investigated for capturing carbon dioxide from dry flue ... A two-stage vacuum pressure swing adsorption(VPSA)process that coupled kinetically controlled and equilibrium controlled separation process with reflux has been investigated for capturing carbon dioxide from dry flue gas(85%N_(2)/15%CO_(2)).In the first enriching stage,carbon molecular sieve(CMS),which shows kinetic selectivity for CO_(2)/N_(2),is adopted as the adsorbent to remove most N_(2)in feed gas,thereby upgrading CO_(2)and significantly reducing the amount for further refinement.The second stage loads zeolite 13X as adsorbent to purify the CO_(2)-rich flow from the first stage for meeting the requirements of National Energy Technology Laboratory.Series of experiments have been conducted for adsorption isotherms measuring and lab-scale experimental validation as well as analysis.The effect of feed composition on the separation performance of the PSA system was studied experimentally and theoretically here.The optimal results achieved 95.1%purity and 92.9%recovery with a high CO_(2)productivity(1.89 mol CO_(2)·h^(-1)·kg^(-1))and an appropriate energy consumption of 1.07 MJ·(kg CO_(2))^(-1).Further analysis has been carried out by simulation for explicating the temperature,pressure,and concentration distribution at cyclic steady state. 展开更多
关键词 two-stage VPSA process Binary mixture CO_(2)capture Zeolite 13X Carbon molecular sieve
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Two-Stage Planning of Distributed Power Supply and Energy Storage Capacity Considering Hierarchical Partition Control of Distribution Network with Source-Load-Storage
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作者 Junhui Li Yuqing Zhang +4 位作者 Can Chen Xiaoxiao Wang Yinchi Shao Xingxu Zhu Cuiping Li 《Energy Engineering》 EI 2024年第9期2389-2408,共20页
Aiming at the consumption problems caused by the high proportion of renewable energy being connected to the distribution network,it also aims to improve the power supply reliability of the power system and reduce the ... Aiming at the consumption problems caused by the high proportion of renewable energy being connected to the distribution network,it also aims to improve the power supply reliability of the power system and reduce the operating costs of the power system.This paper proposes a two-stage planning method for distributed generation and energy storage systems that considers the hierarchical partitioning of source-storage-load.Firstly,an electrical distance structural index that comprehensively considers active power output and reactive power output is proposed to divide the distributed generation voltage regulation domain and determine the access location and number of distributed power sources.Secondly,a two-stage planning is carried out based on the zoning results.In the phase 1 distribution network-zoning optimization layer,the network loss is minimized so that the node voltage in the area does not exceed the limit,and the distributed generation configuration results are initially determined;in phase 2,the partition-node optimization layer is planned with the goal of economic optimization,and the distance-based improved ant lion algorithm is used to solve the problem to obtain the optimal distributed generation and energy storage systemconfiguration.Finally,the IEEE33 node systemwas used for simulation.The results showed that the voltage quality was significantly improved after optimization,and the overall revenue increased by about 20.6%,verifying the effectiveness of the two-stage planning. 展开更多
关键词 Zoning control two-stage planning site selection and capacity determination optimized scheduling improved ant lion algorithm
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Empirical Study of Classification Process for Two-stage Turbo Air Classifier in Series 被引量:1
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作者 YU Yuan LIU Jiaxiang LI Gang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第3期526-531,共6页
The suitable process parameters for a two-stage turbo air classifier are important for obtaining the ultrafine powder that has a narrow particle-size distribution, however little has been published internationally on ... The suitable process parameters for a two-stage turbo air classifier are important for obtaining the ultrafine powder that has a narrow particle-size distribution, however little has been published internationally on the classification process for the two-stage turbo air classifier in series. The influence of the process parameters of a two-stage turbo air classifier in series on classification performance is empirically studied by using aluminum oxide powders as the experimental material. The experimental results show the following: 1) When the rotor cage rotary speed of the first-stage classifier is increased from 2 300 r/min to 2 500 r/min with a constant rotor cage rotary speed of the second-stage classifier, classification precision is increased from 0.64 to 0.67. However, in this case, the final ultrafine powder yield is decreased from 79% to 74%, which means the classification precision and the final ultrafine powder yield can be regulated through adjusting the rotor cage rotary speed of the first-stage classifier. 2) When the rotor cage rotary speed of the second-stage classifier is increased from 2 500 r/min to 3 100 r/min with a constant rotor cage rotary speed of the first-stage classifier, the cut size is decreased from 13.16 μm to 8.76 μm, which means the cut size of the ultrafine powder can be regulated through adjusting the rotor cage rotary speed of the second-stage classifier. 3) When the feeding speed is increased from 35 kg/h to 50 kg/h, the 'fish-hook' effect is strengthened, which makes the ultrafine powder yield decrease. 4) To weaken the 'fish-hook' effect, the equalization of the two-stage wind speeds or the combination of a high first-stage wind speed with a low second-stage wind speed should be selected. This empirical study provides a criterion of process parameter configurations for a two-stage or multi-stage classifier in series, which offers a theoretical basis for practical production. 展开更多
关键词 two-stage turbo air classifier in series aluminum oxide powders process parameters classification performance
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Combustion Characteristics and Emission of a Two-Stroke Compression Ignition Engine with Two-Stage Injection
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作者 宋军 吕兴才 +1 位作者 李孝禄 黄震 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第1期53-60,共8页
In order to study the effect of two-stage injection on two-stroke diesel engines, a well characterized research engine equipped with electronically controlled common rail system and scavenging system was constructed. ... In order to study the effect of two-stage injection on two-stroke diesel engines, a well characterized research engine equipped with electronically controlled common rail system and scavenging system was constructed. Through analysis of combustion and emissions, two-stage injection shows its advantages. Compared with the standard injection, it produces less emissions, while compared with single early injection, it expands engine operation range. Further experiments were carried out to study the influence of several injection control parameters on two-stage injection. The fuel in the first injection is used for forming homogeneous mixture. The fuel in the second injection keeps combustion, and it is the main source of smoke emissions. NO_x is formed in both combustion process caused by these two injections, and there is an optimum fuel allocation ration to produce minimum NO_x. The cylinder pressure decreases, and the combustion is depressed with the increasing of scavenging pressure. By optimizing the injection control parameters of two-stage injection, NO_x and smoke can be reduced beyond 30% simultaneously. 展开更多
关键词 two-stage injection TWO-STROKE diesel engine COMBUSTION EMISSION
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Two-Stage Inspection Model Based on a Three-Stage Failure Process
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作者 杨瑞锋 康建设 王广彦 《Journal of Donghua University(English Edition)》 EI CAS 2016年第2期215-218,共4页
As the non-periodic inspections are common in practice,a two-stage inspection model based on a three-stage failure process is proposed. The two-stage inspection means that the system is inspected with the first inspec... As the non-periodic inspections are common in practice,a two-stage inspection model based on a three-stage failure process is proposed. The two-stage inspection means that the system is inspected with the first inspection interval T_1 and the second inspection interval T_2. Because of the three color schemes commonly used in industry,three stages are divided by the system lifetime:normal, minor defective and severe defective stages. Upon the failure of the system,replacement is carried out. Maintenance is done once identifying the severe defective stage. However,when the minor defective stage is identified by the second inspection interval T_2,action of halving the subsequent inspection interval is adopted.Otherwise,no action is required. Our objective function is to optimize the inspection intervals so as to minimize the expected cost per unit time. Finally,a numerical example is presented to illustrate the effectiveness of the proposed model. 展开更多
关键词 delay time two-stage inspection three-stage failure process preventive maintenance(PM)
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Nonlinear Modeling for a Two-Stage Degradation System Based on Nonhomogeneous Poisson Process
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作者 倪祥龙 赵建民 +2 位作者 赵劲松 郭驰名 杨瑞锋 《Journal of Donghua University(English Edition)》 EI CAS 2015年第6期932-935,共4页
The degradation process modeling is one of research hotspots of prognostic and health management(PHM),which can be used to estimate system reliability and remaining useful life(RUL).In order to study system degradatio... The degradation process modeling is one of research hotspots of prognostic and health management(PHM),which can be used to estimate system reliability and remaining useful life(RUL).In order to study system degradation process,cumulative damage model is used for degradation modeling.Assuming that damage increment is Gamma distribution,shock counting subjects to a homogeneous Poisson process(HPP)when degradation process is linear,and shock counting is a non-homogeneous Poisson process(NHPP)when degradation process is nonlinear.A two-stage degradation system is considered in this paper,for which the degradation process is linear in the first stage and the degradation process is nonlinear in the second stage.A nonlinear modeling method for considered system is put forward,and reliability model and remaining useful life model are established.A case study is given to validate the veracities of established models. 展开更多
关键词 two-stage degradation process NONLINEAR cumulative damage model non-homogeneous Poisson process(NHPP)
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Treatment of methanol wastewater with two-stage and two-phase anaerobic process
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作者 韩洪军 马文成 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2010年第1期65-69,共5页
The two-stage and two-phase anaerobic process (TSTP) composed of hydrolytic acidification reactor,first-order and second-order external circulation anaerobic reactors (EC) was taken to treat methanol wastewater. Test ... The two-stage and two-phase anaerobic process (TSTP) composed of hydrolytic acidification reactor,first-order and second-order external circulation anaerobic reactors (EC) was taken to treat methanol wastewater. Test results show that TSTP process is quick start-up in 51 d, and the maximum VFA of hydrolytic acidification reactor effluent reaches 876 mg/L. Under the condition of volume loading of 6.56 kgCOD/m3·d, COD removal rate of the first-order EC reactor is about 85%, and under the condition of volume loading of 1.02 kgCOD/m3·d, COD removal rate of the second-order EC reactor is about 50%. When the inflow COD of TSTP process is between 7000-11000 mg/L, its effluent COD is lower than 600 mg/L. In the biological conversion process of methanol into methane,the production of acetic acids as an intermediate product can be ignored and the direct production of methane from methanol is predominant. 展开更多
关键词 methanol wastewater two-stage and two-phase anaerobic process (TSTP) external circulation anaerobic reactor (EC) hydrolytic acidification reactor
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An interacting multiple model-based two-stage Kalman filter for vehicle positioning 被引量:2
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作者 徐启敏 李旭 +1 位作者 李斌 宋向辉 《Journal of Southeast University(English Edition)》 EI CAS 2017年第2期177-181,共5页
To address the problem that a general augmented state Kalman filter or a two-stage Kalman filter cannot achieve satisfactory positioning performance when facing uncertain noise of the micro-electro-mechanical system(... To address the problem that a general augmented state Kalman filter or a two-stage Kalman filter cannot achieve satisfactory positioning performance when facing uncertain noise of the micro-electro-mechanical system(MEMS) inertial sensors, a novel interacting multiple model-based two-stage Kalman filter(IMM-TSKF) is proposed to adapt to the uncertain inertial sensor noise. Three bias filters are developed based on different noise characteristics to cover a wide range of noise levels. Then, an accurate estimation of biases is calculated by the interacting multiple model algorithm to correct the bias-free filter. Thus, the vehicle positioning system can achieve good performance when suffering from uncertain inertial sensor noise. The experimental results indicate that the average position error of the proposed IMMTSKF is 25% lower than that of the general TSKF. 展开更多
关键词 interacting multiple model(IMM) two-stage filter uncertain noise vehicle positioning
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基于Two-stage DEA-Tobit模型的中国省际竞技体育效率研究 被引量:3
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作者 王婵 朱达 +1 位作者 唐亮 于瑛英 《湖北大学学报(自然科学版)》 CAS 2020年第1期1-11,共11页
基于Two-stage DEA的网络结构DEA方法,对我国31个省(直辖市、自治区)在第十二届全运会上的表现进行更深入的效率评价,并结合Tobit回归模型对影响竞技体育效率的社会环境因素进行分析.结果表明,全运会两个阶段中,仅山东省和西藏自治区为... 基于Two-stage DEA的网络结构DEA方法,对我国31个省(直辖市、自治区)在第十二届全运会上的表现进行更深入的效率评价,并结合Tobit回归模型对影响竞技体育效率的社会环境因素进行分析.结果表明,全运会两个阶段中,仅山东省和西藏自治区为DEA有效的,AP阶段和AC阶段为DEA有效的地区分别为10个和3个,且提高各地区总效率的关键在于提高其AC阶段效率.从影响因素来看,地区经济水平与效率间存在负向影响,而体育场地资源配置及体育类支出是影响效率的主要因素,国民体质综合指数和体育投入规模对其无显著影响. 展开更多
关键词 竞技体育 效率 two-stage DEA TOBIT回归
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