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Research on pedestrian escape route without visibility based on Markov chain model

Xiaoping ZHENG, Lijuan DU, Hongjiang WANG,

《化学科学与工程前沿（英文）》 2010年 第4卷 第3期   页码 283-289 doi: 10.1007/s11705-009-0272-8

摘要： It is a pioneering work to use a Markov chain model to study the pedestrian escape route without visibility. In this paper, based on the Markov chain probability transition matrix, the algorithms with random numbers and the spatial-grid, an escape route in a limited invisible space is obtained. Six pace states (standing, crawling, walking, leaping, jogging, and running) are applied to describe the characteristics of pedestrian behaviors. Besides, eight main direction changes are used to describe the transition characteristic of a pedestrian. At the same time, this paper analyzes the escape route from two views, i.e., pedestrian pace states and directions. The research results show that the Markov chain model is more realistic as a means of studying pedestrian escape routes.

关键词： pioneering     direction     spatial-grid     realistic     transition characteristic    

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Analysis of the dynamic hysteresis characteristic of finger seal

LEI Yanni, CHEN Guoding

《机械工程前沿（英文）》 2007年 第2卷 第1期   页码 32-36 doi: 10.1007/s11465-007-0005-y

摘要： The research about hysteresis characteristic of finger seal (FS), which was carried out based on the model with static loads, could not reflect the dynamics behavior of FS system when the rotor runs at high speed. To solve this problem, the relations between the dynamics parameters, structure parameters as well as working parameters in the system were given out through the analysis of finite element analysis result. A mass spring damper dynamics model of FS system was proposed and the hysteresis characteristic of the FS system was analyzed. This work shows that the dynamics characteristic analysis of the FS is necessary and the dynamics model proposed in this paper is valid. This dynamics model is the basis for the optimization design of FS system.

关键词： FS     necessary     hysteresis characteristic     optimization     spring    

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Epithelial-to-mesenchymal transition in cancer: complexity and opportunities

Yun Zhang, Robert A. Weinberg

《医学前沿（英文）》 2018年 第12卷 第4期   页码 361-373 doi: 10.1007/s11684-018-0656-6

摘要：

The cell-biological program termed the epithelial-to-mesenchymal transition (EMT) plays an important role in both development and cancer progression. Depending on the contextual signals and intracellular gene circuits of a particular cell, this program can drive fully epithelial cells to enter into a series of phenotypic states arrayed along the epithelial-mesenchymal phenotypic axis. These cell states display distinctive cellular characteristics, including stemness, invasiveness, drug-resistance and the ability to form metastases at distant organs, and thereby contribute to cancer metastasis and relapse. Currently we still lack a coherent overview of the molecular and biochemical mechanisms inducing cells to enter various states along the epithelial-mesenchymal phenotypic spectrum. An improved understanding of the dynamic and plastic nature of the EMT program has the potential to yield novel therapies targeting this cellular program that may aid in the management of high-grade malignancies.

关键词： epithelial-to-mesenchymal transition     cancer     metastasis     cancer stem cell    

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Phase transition regulation and caloric effect

《能源前沿（英文）》 2023年 第17卷 第4期   页码 463-477 doi: 10.1007/s11708-023-0860-1

摘要： Solid state refrigeration based on caloric effect is regarded as a potential candidate for replacing vapor-compression refrigeration. Numerous methods have been proposed to optimize the refrigeration properties of caloric materials, of which single field tuning as a relatively simple way has been systemically studied. However, single field tuning with few tunable parameters usually obtains an excellent performance in one specific aspect at the cost of worsening the performance in other aspects, like attaining a large caloric effect with narrowing the transition temperature range and introducing hysteresis. Because of the shortcomings of the caloric effect driven by a single field, multifield tuning on multicaloric materials that have a coupling between different ferro-orders came into view. This review mainly focuses on recent studies that apply this method to improve the cooling performance of materials, consisting of enlarging caloric effects, reducing hysteresis losses, adjusting transition temperatures, and widening transition temperature spans, which indicate that further progress can be made in the application of this method. Furthermore, research on the sign of lattice and spin contributions to the magnetocaloric effect found new phonon evolution mechanisms, calling for more attention on multicaloric effects. Other progress including improving cyclability of FeRh alloys by introducing second phases and realizing a large reversible barocaloric effect by hybridizing carbon chains and inorganic groups is described in brief.

关键词： phase transition regulation     caloric effect     solid state refrigeration    

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Energy transition management towards a low-carbon world

《工程管理前沿（英文）》 2022年 第9卷 第3期   页码 499-503 doi: 10.1007/s42524-022-0201-9

关键词： energy transition     low-carbon technology     system modeling     transition path     emission reduction    

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Smart oilfield development and transition of petroleum-based cities

He LIU, Xinhua MA

《工程管理前沿（英文）》 2019年 第6卷 第2期   页码 299-301 doi: 10.1007/s42524-019-0024-5

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Energy transition toward carbon-neutrality in China: Pathways, implications and uncertainties

《工程管理前沿（英文）》 2023年 第10卷 第2期   页码 358-372 doi: 10.1007/s42524-022-0202-8

摘要： Achieving carbon neutrality in China before 2060 requires a radical energy transition. To identify the possible transition pathways of China’s energy system, this study presents a scenario-based assessment using the Low Emissions Analysis Platform (LEAP) model. China could peak the carbon dioxide (CO2) emissions before 2030 with current policies, while carbon neutrality entails a reduction of 7.8 Gt CO2 in emissions in 2060 and requires an energy system overhaul. The assessment of the relationship between the energy transition and energy return on investment (EROI) reveals that energy transition may decrease the EROI, which would trigger increased energy investment, energy demand, and emissions. Uncertainty analysis further shows that the slow renewable energy integration policies and carbon capture and storage (CCS) penetration pace could hinder the emission mitigation, and the possible fossil fuel shortage calls for a much rapid proliferation of wind and solar power. Results suggest a continuation of the current preferential policies for renewables and further research and development on deployment of CCS. The results also indicate the need for backup capacities to enhance the energy security during the transition.

关键词： carbon neutrality     energy transition     uncertainty     EROI     LEAP    

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Flow characteristic and wastewater treatment performance of a pilot-scale airlift oxidation ditch

Hongtao PANG, Hanchang SHI, Huiming SHI,

《环境科学与工程前沿（英文）》 2009年 第3卷 第4期   页码 470-476 doi: 10.1007/s11783-009-0143-z

摘要： A pilot-scale airlift oxidation ditch using bubble diffuser and baffle as aerator was operated in a wastewater treatment plant (WWTP) to investigate its flow characteristic and wastewater treatment performance. Compared with the conventional oxidation ditch process, effective depth and oxygen utilization efficiency of this new process was improved by underwater aeration. Furthermore, it had a reversed velocity distribution, which decreased from the bottom to the top on vertical section. Velocity measurement showed that a velocity over 0.2m/s at the bottom was sufficient to prevent sludge settlement during long term operation. Application of these concepts would save land area and energy consumption by about 25%―50% and 55%, respectively. In this new system, organic biodegradation and nitrification could be well achieved. Denitrification could occur steadily in the straight part by adjusting the airflow rate. An average TN removal rate of 63% was achieved with dissolved oxygen (DO) concentrations between 0.6mg/L and 1.5mg/L. The main pollutants in the effluent could meet the strictest discharge standard (COD<50mg/L, NH―N<5mg/L, and TN<15mg/L) in China now.

关键词： airlift oxidation ditch     flow characteristic     wastewater treatment    

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Weak characteristic information extraction from early fault of wind turbine generator gearbox

Xiaoli XU, Xiuli LIU

《机械工程前沿（英文）》 2017年 第12卷 第3期   页码 357-366 doi: 10.1007/s11465-017-0423-4

摘要：

Given the weak early degradation characteristic information during early fault evolution in gearbox of wind turbine generator, traditional singular value decomposition (SVD)-based denoising may result in loss of useful information. A weak characteristic information extraction based on µ-SVD and local mean decomposition (LMD) is developed to address this problem. The basic principle of the method is as follows: Determine the denoising order based on cumulative contribution rate, perform signal reconstruction, extract and subject the noisy part of signal to LMD and µ-SVD denoising, and obtain denoised signal through superposition. Experimental results show that this method can significantly weaken signal noise, effectively extract the weak characteristic information of early fault, and facilitate the early fault warning and dynamic predictive maintenance.

关键词： wind turbine generator gearbox     µ-singular value decomposition     local mean decomposition     weak characteristic information extraction     early fault warning    

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Policy entry points for facilitating a transition towards a low-carbon electricity future

《工程管理前沿（英文）》   页码 462-472 doi: 10.1007/s42524-022-0214-4

摘要： This study extends the ambit of the debate on electricity transition by specifically identifying possible policy entry points through which transformative and enduring changes can be made in the electricity and socio–economic systems to facilitate the transition process. Guided by the “essence” of the multi-level perspective — a prominent framework for the study of energy transition, four such entry points have been identified: 1) destabilising the dominant, fossil fuel-based electricity regime to create room for renewable technologies to break through; 2) reconfiguring the electricity regime, which encompasses technology, short-term operational practices and long-term planning processes, to improve flexibility for accommodating large outputs from variable renewable sources whilst maintaining supply security; 3) addressing the impact of coal power phase-out on coal mining regions in terms of economic development and jobs; and 4) facilitating a shift in transition governance towards a learning-based, reflexive process. Specific areas for policy interventions within each of these entry points have also been discussed in the paper.

关键词： electricity transition     multi-level perspective     policy entry points    

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Kinetic roughening transition and missing regime transition of melt crystallized polybutene-1 tetragonal

Motoi YAMASHITA

《化学科学与工程前沿（英文）》 2009年 第3卷 第2期   页码 125-134 doi: 10.1007/s11705-009-0001-3

摘要： The morphology and lateral growth rate of polybutene-1 ( -PB1) have been investigated for crystallization from the melt over a wide range of crystallization temperatures from 50 to 110°C. The morphology of -PB1 crystals is a rounded shape at crystallization temperatures lower than 85°C, while lamellar single crystals possess faceted morphology at higher crystallization temperatures. The kinetic roughening transition occurs around 85°C. The nucleation and growth mechanism for crystallization does not work below 85°C, since the growth face is rough. However, the growth rate shows the supercooling dependence derived from the nucleation and growth mechanism. The nucleation theory seems still to work even for rough surface growth. Possible mechanisms for the crystal growth of this polymer are discussed.

关键词： isotactic polybutene-1     tetragonal phase (form Ⅱ)     melt crystallization     growth rate     kinetic roughening     morphology    

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Microwave-induced high-energy sites and targeted energy transition promising for efficient energy deployment

《能源前沿（英文）》 2022年 第16卷 第6期   页码 931-942 doi: 10.1007/s11708-021-0771-y

摘要： Diverse interactions between microwaves and irradiated media provide a solid foundation for identifying novel organization pathways for energy flow. In this study, a high-energy-site phenomenon and targeted-energy transition mechanism were identified in a particular microwave heating (MH) process. Intense discharges were observed when microwaves were imposed on irregularly sized SiC particles, producing tremendous heat that was 8-fold the amount generated in the discharge-free case. Energy efficiency was thereby greatly improved in the electricity-microwaves-effective heat transition. Meanwhile, the dispersed microwave field energy concentrated in small sites, where local temperatures could reach 2000°C– 4000°C, with the energy density reaching up to 4.0 × 105 W/kg. This can be called a high-energy site phenomenon which could induce further processes or reactions enhancement by coupling effects of heat, light, and plasma. The whole process, including microwave energy concentration and intense site-energy release, shapes a targeted-energy transition mechanism that can be optimized in a controlled manner through morphology design. In particular, the discharge intensity, frequency, and high-energy sites were strengthened through the fabrication of sharp nano/microstructures, conferring twice the energy efficiency of untreated metal wires. The microwave-induced high-energy sites and targeted energy transition provide an important pathway for high-efficiency energy deployment and may lead to promising applications.

关键词： microwave discharge     high-energy sites     targeted-energy transition     morphology design     energy efficiency    

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Special issue: Transition management of energy systems towards carbon neutrality

《工程管理前沿（英文）》 2022年 第9卷 第3期   页码 355-357 doi: 10.1007/s42524-022-0219-z

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On Social-technical Control of Safety Development in Economic Transition Background

Xue-qiu He,Song Li

《工程管理前沿（英文）》 2015年 第2卷 第3期   页码 234-240 doi: 10.15302/J-FEM-2015025

摘要： Industrial safety and economic growth, two vital and inextricable forces affecting national culture and development, are worthy of much more interest and attention than this article can hope to generate. Following economic growth, industrial safety remains as a high priority in this nation’s quest for sustainable development. At present, while China is on its way to transforming its economic structure and growth models, talk of industrial safety appears with special regularity, for it also is undergoing profound changes as an important facet of modern China.

关键词： safety development     economic growth     economic transition     social-technical control    

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中国能源困境与转型

石元春

《中国工程科学》 2009年 第11卷 第11期   页码 4-12

摘要：

中国石油和天然气资源贫乏，进口依存度超过50 %，煤炭的储产比也降到了50以下。中国能源消费结构中煤炭占到七成，CO2排放超过美国。能源转型是当今世界，也是中国发展的大趋势。能源转型的方向是清洁能源，发展清洁能源的重点是可再生能源。中国清洁能源资源具有替代现能源消费总量七成以上的潜力；可再生能源中的小水电、风能和生物质能的可经济利用资源量分别是0.63亿吨，1.23亿吨和10.47亿吨（标煤）。中国生物质原料资源最丰富，而且可以立竿见影地增加农民收入，促进农村经济发展，是发展可再生能源和能源转型的战略重点。

关键词： 中国能源     困境     转型    

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标题 作者 时间 类型 操作

Research on pedestrian escape route without visibility based on Markov chain model

Xiaoping ZHENG, Lijuan DU, Hongjiang WANG,

期刊论文

Analysis of the dynamic hysteresis characteristic of finger seal

LEI Yanni, CHEN Guoding

期刊论文

Epithelial-to-mesenchymal transition in cancer: complexity and opportunities

Yun Zhang, Robert A. Weinberg

期刊论文

Phase transition regulation and caloric effect

期刊论文

Energy transition management towards a low-carbon world

期刊论文

Smart oilfield development and transition of petroleum-based cities

He LIU, Xinhua MA

期刊论文

Energy transition toward carbon-neutrality in China: Pathways, implications and uncertainties

期刊论文

Flow characteristic and wastewater treatment performance of a pilot-scale airlift oxidation ditch

Hongtao PANG, Hanchang SHI, Huiming SHI,

期刊论文

Weak characteristic information extraction from early fault of wind turbine generator gearbox

Xiaoli XU, Xiuli LIU

期刊论文

Policy entry points for facilitating a transition towards a low-carbon electricity future

期刊论文

Kinetic roughening transition and missing regime transition of melt crystallized polybutene-1 tetragonal

Motoi YAMASHITA

期刊论文

Microwave-induced high-energy sites and targeted energy transition promising for efficient energy deployment

期刊论文

Special issue: Transition management of energy systems towards carbon neutrality

期刊论文

On Social-technical Control of Safety Development in Economic Transition Background

Xue-qiu He,Song Li

期刊论文

中国能源困境与转型

石元春

期刊论文