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Experimental study of stratified lean burn characteristics on a dual injection gasoline engine

Chun XIA, Tingyu ZHAO, Junhua FANG, Lei ZHU, Zhen HUANG

《能源前沿（英文）》 2022年 第16卷 第6期   页码 900-915 doi: 10.1007/s11708-021-0812-6

摘要： Due to increasingly stringent fuel consumption and emission regulation, improving thermal efficiency and reducing particulate matter emissions are two main issues for next generation gasoline engine. Lean burn mode could greatly reduce pumping loss and decrease the fuel consumption of gasoline engines, although the burning rate is decreased by higher diluted intake air. In this study, dual injection stratified combustion mode is used to accelerate the burning rate of lean burn by increasing the fuel concentration near the spark plug. The effects of engine control parameters such as the excess air coefficient (Lambda), direct injection (DI) ratio, spark interval with DI, and DI timing on combustion, fuel consumption, gaseous emissions, and particulate emissions of a dual injection gasoline engine are studied. It is shown that the lean burn limit can be extended to Lambda= 1.8 with a low compression ratio of 10, while the fuel consumption can be obviously improved at Lambda= 1.4. There exists a spark window for dual injection stratified lean burn mode, in which the spark timing has a weak effect on combustion. With optimization of the control parameters, the brake specific fuel consumption (BSFC) decreases 9.05% more than that of original stoichiometric combustion with DI as 2 bar brake mean effective pressure (BMEP) at a 2000 r/min engine speed. The NOx emissions before three-way catalyst (TWC) are 71.31% lower than that of the original engine while the particle number (PN) is 81.45% lower than the original engine. The dual injection stratified lean burn has a wide range of applications which can effectively reduce fuel consumption and particulate emissions. The BSFC reduction rate is higher than 5% and the PN reduction rate is more than 50% with the speed lower than 2400 r/min and the load lower than 5 bar.

关键词： dual injection     stratified lean burn     gasoline engine     particulate matter emission     combustion analysis    

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Numerical simulation of charge stratifications to improve combustion and NO formation of lean-burn SI

Zhijun PENG ,

《能源前沿（英文）》 2009年 第3卷 第3期   页码 353-358 doi: 10.1007/s11708-009-0035-8

摘要： The influences of charge stratification on spark ignition (SI) engine combustion and NO emission were analyzed using a phenomenological model. The mixture in the cylinder was divided spherically into three parts: a central core with a stoichiometric air-fuel charge, a dilution region without any combustible charge, and a mixing region lying between the core and the dilution region. Three mixture stratification parameters such as the extent of dilution in the mixing region, the extent of combustible charge in the mixing region, and the gradient of stratification in the mixing region were investigated. The results indicate that the extent of combustible charge in the mixing region could reduce in-cylinder NO formation significantly, compared with the extent of dilution in the mixing region. As long as the degree of dilution in the mixing region is within the dilution limit of the combustible charge, the gradient of dilution has little effect on combustion and NO formation.

关键词： charge stratification     SI engine     lean-burn combustion     NO emission    

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Progress in developing an innovative lean burn catalytic turbine technology for fugitive methane mitigation

Shi SU, Xinxiang YU

《能源前沿（英文）》 2011年 第5卷 第2期   页码 229-235 doi: 10.1007/s11708-011-0147-9

摘要： Approximately 2.8 × 10 m of methane is emitted per year to the atmosphere from coal mining activities around the world. Mitigation and utilization of the fugitive coal mine methane is very difficult because its concentration is very low and varies from 0.1% to1%, and the methane is contained in a large air flow rate of 150–400 m /s. This paper overviews existing and developing technologies for the mitigation and utilization of the fugitive mine methane, and then presents research progress in developing an innovative lean burn catalytic turbine technology for fugitive methane mitigation and utilization. This turbine system can be powered with about 1% methane in air.

关键词： coal mine methane     mitigation and utilization     lean burn gas turbine     catalytic combustion    

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Selective catalytic reduction of NOx from exhaust of lean-burn engine over Ag-Al2O3/cordierite catalyst

LI Junhua, KANG Shoufang, FU Lixin, HAO Jiming

《环境科学与工程前沿（英文）》 2007年 第1卷 第2期   页码 143-146 doi: 10.1007/s11783-007-0025-1

摘要： A highly effective Ag-AlO catalyst was prepared using the sol-gel method, and characterized by surface area using nitrogen adsorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The catalyst performance was tested on a real lean-burn gasoline engine. Only unburned hydrocarbons and carbon monoxide in the exhaust were directly used as reductant (without any external reductant), the maximum NO conversion could only reach 40% at 450?C. When an external reductant, ethanol was added, the average NO conversion was greater than 60%. At exhaust gas temperature range of 350 500?C, the maximum NO conversion reached about 90%. CO and HC could be efficiently oxidized with Pt-AO oxidation catalyst placed at the end of SCR converter. However, NO conversion drastically decreased because of the oxidation of some intermediates to NO again. The possible reaction mechanism was proposed as two typical processes, nitration, and reduction in HC-SCR over Ag-AlO.

关键词： lean-burn gasoline     external reductant     nitrogen adsorption     conversion     catalyst performance    

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Sequential degradation-based burn-in test with multiple periodic inspections

《工程管理前沿（英文）》 2021年 第8卷 第4期   页码 519-530 doi: 10.1007/s42524-021-0166-0

摘要： Burn-in has been proven effective in identifying and removing defective products before they are delivered to customers. Most existing burn-in models adopt a one-shot scheme, which may not be sufficient enough for identification. Borrowing the idea from sequential inspections for remaining useful life prediction and accelerated lifetime test, this study proposes a sequential degradation-based burn-in model with multiple periodic inspections. At each inspection epoch, the posterior probability that a product belongs to a normal one is updated with the inspected degradation level. Based on the degradation level and the updated posterior probability, a product can be disposed, put into field use, or kept in the test till the next inspection epoch. We cast the problem into a partially observed Markov decision process to minimize the expected total burn-in cost of a product, and derive some interesting structures of the optimal policy. Then, algorithms are provided to find the joint optimal inspection period and number of inspections in steps. A numerical study is also provided to illustrate the effectiveness of our proposed model.

关键词： burn-in     degradation     multiple inspections     Wiener process     partially observed Markov decision process    

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Monocyte subsets and their differentiation tendency after burn injury

null

《医学前沿（英文）》 2013年 第7卷 第4期   页码 397-400 doi: 10.1007/s11684-013-0298-7

摘要：

Monocytes are critical effectors and regulators of immune response. Studying the nomenclature of monocyte subsets may be beneficial for understanding the complex function of monocytes in steady and inflammatory states. A monocyte has the potential to differentiate into dendritic cells or macrophages, and this behavior significantly changes in severely burned patients and mice. The findings in the present study may help enhance understanding on the perturbation of the immune system after severe burn injury.

关键词： monocyte     differentiation     burn    

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Lean Product Development—Faster, Better … Cleaner?

Geert Letens

《工程管理前沿（英文）》 2015年 第2卷 第1期   页码 52-59 doi: 10.15302/J-FEM-2015007

摘要： To address this challenge, lean product development has emerged to become the leading improvement methodology for companies toward the creation of a competitive advantage on innovation and technology leadership. While lean product development has its origin in the best practice studies of Japanese car manufacturers such as Toyota, it has been further elaborated in defence and aerospace organizations over the last two decades, and recently empirical evidence has become available for successful introductions in sectors different from the traditionally-studied environments. The primary purpose of this work is to untangle the fuzziness that still surrounds lean product development and to ground the key aspects of lean product development based on insights from six studies published in a special issue of the on this topic. This demonstrates how better and faster product development can be achieved through the integration of lean principles with the best of more traditional new product development (NPD) practices, into a holistic system that can be characterised by value-focused and risk-based decision making, the socio-technical integration of people and process, improved project, pipeline and portfolio management, optimized knowledge management, and the creation of a learning organization. Unfortunately, while the increasing global competition offers the potential to improve the quality of life for many, the spirit of faster, better, and cheaper also threatens to endanger the future of our planet as a whole. As the majority of a product’s social and ecological impacts are committed in the design phase, it, therefore, seems imperative to investigate the integration of lean product development and eco-design principles. As a result, this work also explores the symbiosis of both approaches through the identification of tools and methods that can support the triple bottom-line goals for a sustainable future of life and business.

关键词： lean product development     sustainability engineering     responsible design    

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Achievements in burn surgery over the past 50 years in China

WANG Shiliang

《医学前沿（英文）》 2008年 第2卷 第4期   页码 332-336 doi: 10.1007/s11684-008-0063-5

摘要： This paper reflects on the advancements of clinical and scientific research in the field of burn surgery in China. It includes emergency care of massive burns, resuscitation, anti-infection, prevention and cure of internal organ injuries, metabolic and nutritional support, wound repair and rehabilitation, and special types of burns; it also covers pathology, microbiology, immunology, cell biology, molecular biology, and tissue engineering.

关键词： immunology     scientific     nutritional     microbiology     engineering    

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Seepage failure by heave in sheeted excavation pits constructed in stratified cohesionless soils

Serdar KOLTUK, Jie SONG, Recep IYISAN, Rafig AZZAM

《结构与土木工程前沿（英文）》 2019年 第13卷 第6期   页码 1415-1431 doi: 10.1007/s11709-019-0565-z

摘要： In this study, experimental and numerical investigations are performed to clarify the seepage failure by heave in sheeted excavation pits in stratified cohesionless soils in which a relatively permeable soil layer ( ) lies above a less permeable soil layer ( ) between excavation base and wall tip. It is shown that the evaluation of base stabilities of excavation pits against seepage failure by using Terzaghi and Peck’s approach leads to considerably lower critical potential differences than those obtained from the model tests. On the other hand, a relatively good agreement is achieved between the results of the model tests and the finite element (FE) analyses. Further investigations are performed by using axisymmetric excavation models with various dimensions and ground conditions, and a comparison between the results obtained from Terzaghi and Peck’s approach and finite element analyses is given.

关键词： seepage failure by heave     cohesionless stratified soil     model test     Terzaghi and Peck’s approach     FE analysis    

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Proposing a “lean and green” framework for equipment cost analysis in construction

Ming LU, Nicolas DIAZ, Monjurul HASAN

《工程管理前沿（英文）》 2019年 第6卷 第3期   页码 384-394 doi: 10.1007/s42524-019-0033-4

摘要： One limitation of previous productivity-driven research on equipment selection and operation simulation lies in the fact that the green aspects of construction activities have been largely neglected in analysis of costefficiency of construction operations. On the other hand, studies attempting to measure greenhouse gas emission due to construction activities have yet to develop a methodology that correlates their findings and implications with construction productivity. In order to address the immediate need for improving the sustainability performance of construction projects, it is imperative for the construction industry to evaluate greenhouse gas emission as a cost factor in construction planning, equipment selection, and cost estimating. In this context, this paper formalizes an integrative framework for equipment cost analysis based on the concepts of lean construction and green construction, aimed to guide the selection of appropriate construction equipment considering exhaust emission and productivity performance at the same time. The framework is elaborated in earthwork construction in order to evaluate the impact of greenhouse gas emission in estimating equipment hourly rates and assessing greenness and sustainability for alternative equipment options.

关键词： green construction     lean construction     equipment     simulation     earthwork construction     sustainability     productivity    

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Hotspots Evolution and Frontier Analysis of Lean Construction Research—Integrated Scientometric Analysis

Qing-hua He,Ge Wang

《工程管理前沿（英文）》 2015年 第2卷 第2期   页码 141-147 doi: 10.15302/J-FEM-2015023

摘要： To develop a lean and green construction industry, Lean Construction (LC) is proposed as a new construction production method to improve the efficient use of resources and the value of construction supply chains, which has received increasing research concerns from scholars and practitioners. Based on related articles covered by the Web of Science and Scopus databases between 1995 and 2014, this study conducts a scientometric analysis. The analysis identifies four core topics in existing research, including: Last Planner System (LPS); production control theory; improvement and evaluation of productivity; and principle of value. Three major directions of LC research: greening LC; Building Information Modeling (BIM) based LC; and lean safety management, are also proposed. Lastly, several recommendations for future LC research and practice are provided in the literature review.

关键词： Lean Construction     green industry     efficient use    

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痩肉猪育种的发展及展望

熊远著

《中国工程科学》 2000年 第2卷 第9期   页码 42-46

摘要：

文章对世界的猪育种过程特别是中国的瘦肉猪育种，从猪种资源调査到优良猪种引进与新品种选育，专门化品系选育与配套利用，种猪测定等方面进行了回顾，就分子生物技术在猪遗传育种中的应用及取得的成果作了简要概述。展望了21世纪瘦肉猪育种的目标，并就新品种培育、猪种资源保存、完善种猪测定体系和加速分子生物技术在猪育种中的应用提出了建议。

关键词： 猪     瘦肉型     育种    

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Nitrifying population dynamics in a redox stratified membrane biofilm reactor (RSMBR) for treating ammonium-rich

Rongchang WANG, Xinmin ZHAN, Yalei ZHANG, Jianfu ZHAO

《环境科学与工程前沿（英文）》 2011年 第5卷 第1期   页码 48-56 doi: 10.1007/s11783-011-0305-7

摘要： Nitrogen removal performance and nitrifying population dynamics were investigated in a redox stratified membrane biofilm reactor (RSMBR) under oxygen limited condition to treat ammonium-rich wastewater. When the loading rate increased from 11.1±1.0 to , the nitrogen removal in the RSMBR system increased from 18.0±9.6 mgN·d to 128.9±61.7 mgN·d . Shortcut nitrogen removal was achieved with nitrite accumulation of about . Confocal micrographs showed the stratified distributions of nitrifiers and denitrifiers in the membrane aerated biofilms (MABs) at day 120, i.e., ammonia and nitrite oxidizing bacteria (AOB and NOB) were dominant in the region adjacent to the membrane, while heterotrophic bacteria propagated at the top of the biofilm. Real-time qPCR results showed that the abundance of gene was two orders of magnitude higher than the abundance of gene in the MABs. However, the gene was always detected during the operation time, which indicates the difficulty of complete washout of NOB in MABs. The growth of heterotrophic bacteria compromised the dominance of nitrifiers in biofilm communities, but it enhanced the denitrification performance of the RSMBR system. Applying a high ammonia loading together with oxygen limitation was found to be an effective way to start nitrite accumulation in MABs, but other approaches were needed to sustain or improve the extent of nitritation in nitrogen conversion in MABs.

关键词： ammonium-rich wastewater     membrane biofilm reactor     nitrification     redox stratification     shortcut nitrogen removal    

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Experimental study for the stratified to slug flow regime transition mechanism of gas-oil two-phase flow

LIU Yiping, YANG Weilin, WANG Jing

《能源前沿（英文）》 2008年 第2卷 第2期   页码 152-157 doi: 10.1007/s11708-008-0012-7

摘要： Theoretical relations that predict the transition from a stratified pattern to a slug pattern, including a one-dimensional wave model that contains less empiricism than the commonly used Taitel-Dukler model, and the ideal model for stratified flow for the gas-liquid flow in horizontal pipes are presented. Superficial velocities of each phase, as the onset of slugging occurs, were predicted, and theoretical analysis was conducted on the stratified to slug flow regime transition. The friction, existing between the fluid and pipe wall, and on the interface of two phases, was especially taken into account. A theoretical model was applied to an experiment about air-oil two-phase flow in a 50 mm horizontal pipe. The effect of pipe diameter on the transition was also studied. The results show that this approach gives a reasonable prediction over the whole range of flow rates, and better agreement has been achieved between predicted and measured critical parameters.

关键词： two-phase     Superficial     reasonable prediction     one-dimensional     gas-liquid    

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Blockchain-driven supply chain finance solution for small and medium enterprises

Jian LI, Shichao ZHU, Wen ZHANG, Lean YU

《工程管理前沿（英文）》 2020年 第7卷 第4期   页码 500-511 doi: 10.1007/s42524-020-0124-2

摘要： Blockchain has attracted much attention in recent years with the development of cryptocurrency and digital assets. As the underlying technology of cryptocurrency, blockchain has numerous benefits, such as de-centralization, collective maintenance, tamper-resistance, traceability, and anonymity. The potential of the blockchain technology (BT) is widely recognized in the financial field. Although some scholars have proposed the combination of blockchain and supply chain finance (SCF), the details of this combination is rarely mentioned. This study first analyzes the coupling between SCF and blockchain technology. Second, the conceptual framework of blockchain-driven SCF platform (BcSCFP) is presented. Third, the operation process of three SCF models on the BcSCFP is proposed. Finally, a case study combined with actual events is conducted. This paper has a positive practical significance in the operation and management of banks and loan enterprises.

关键词： blockchain technology     supply chain finance     risk management     smart contract     decentralization    

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标题 作者 时间 类型 操作

Experimental study of stratified lean burn characteristics on a dual injection gasoline engine

Chun XIA, Tingyu ZHAO, Junhua FANG, Lei ZHU, Zhen HUANG

期刊论文

Numerical simulation of charge stratifications to improve combustion and NO formation of lean-burn SI

Zhijun PENG ,

期刊论文

Progress in developing an innovative lean burn catalytic turbine technology for fugitive methane mitigation

Shi SU, Xinxiang YU

期刊论文

Selective catalytic reduction of NOx from exhaust of lean-burn engine over Ag-Al2O3/cordierite catalyst

LI Junhua, KANG Shoufang, FU Lixin, HAO Jiming

期刊论文

Sequential degradation-based burn-in test with multiple periodic inspections

期刊论文

Monocyte subsets and their differentiation tendency after burn injury

null

期刊论文

Lean Product Development—Faster, Better … Cleaner?

Geert Letens

期刊论文

Achievements in burn surgery over the past 50 years in China

WANG Shiliang

期刊论文

Seepage failure by heave in sheeted excavation pits constructed in stratified cohesionless soils

Serdar KOLTUK, Jie SONG, Recep IYISAN, Rafig AZZAM

期刊论文

Proposing a “lean and green” framework for equipment cost analysis in construction

Ming LU, Nicolas DIAZ, Monjurul HASAN

期刊论文

Hotspots Evolution and Frontier Analysis of Lean Construction Research—Integrated Scientometric Analysis

Qing-hua He,Ge Wang

期刊论文

痩肉猪育种的发展及展望

熊远著

期刊论文

Nitrifying population dynamics in a redox stratified membrane biofilm reactor (RSMBR) for treating ammonium-rich

Rongchang WANG, Xinmin ZHAN, Yalei ZHANG, Jianfu ZHAO

期刊论文

Experimental study for the stratified to slug flow regime transition mechanism of gas-oil two-phase flow

LIU Yiping, YANG Weilin, WANG Jing

期刊论文

Blockchain-driven supply chain finance solution for small and medium enterprises

Jian LI, Shichao ZHU, Wen ZHANG, Lean YU

期刊论文