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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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针对Wimax中多用户的考虑状态转移损失的省电算法 Article

Bo LI,Sung-kwon PARK

《信息与电子工程前沿（英文）》 2016年第17卷第10期页码 1085-1094 doi: 10.1631/FITEE.1500314

摘要：概要：在IEEE 802.16e/m标准中，为了节省移动台（mobile subscriber station, MSS）的电量，定义了三种省电类型（power saving classes, PSC）。但是，标准中并未规定如何设置PSC的参数来最大化省电量和确保服务质量（quality of service, QoS）。因此，很多人提出了设置PSC参数的算法。这些算法中大部分只考虑了针对一个MSS的PSC参数设置。在针对多个MSS的算法中，MSS从工作状态到休眠状态转变的电量损失又未被考虑。本论文研究针对多MSS的PSC参数设置问题，并考虑MSS从工作状态到休眠状态转变的电量损失。该问题是NP难问题。我们为该问题提出了一个次优的算法。仿真结果表明我们提出的算法的性能优于当前最好的算法，并且接近于最优极限值。

关键词：省电类型；状态转变损失；IEEE 802.16e/m；服务质量

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State versus private sector provision of water services in Armenia

Naira HARUTYUNYAN

《环境科学与工程前沿（英文）》 2012年第6卷第5期页码 620-630 doi: 10.1007/s11783-012-0425-8

摘要： Despite increasing advocacy and adaptation of public-private model of water governance worldwide since the 1990s, today only 5% of the world’s population is served by water utilities with private involvement. The present article examines the experience of the water sector in Armenia with private sector participation. The study describes the process of the introduction of public-private partnerships in the water sector and focuses on analyzing the impact of privatization on water utility performance. The analysis employs the partial indicator method for evaluating the impacts in relation to operational, finance, and environmental performance, done by drawing on the database for the five water companies in Armenia. The empirical evidence shows that private participation in general led to improved overall performance. In particular, private involvement resulted in increased operational efficiency in terms of labor productivity, water metering, continuity of service, and revenue collection efficiency. There were mixed improvements in the operating cost coverage ratio. As for environmental performance, there were gains in the reduction of residential water consumption, accompanied, however, by an increase in non-revenue water.

关键词： water governance water privatization public-private partnership operational efficiency Armenia transition economy

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Integrated energy in Germany–A critical look at the development and state of integrated energies in Germany

Saman AMANPOUR, Daniel HUCK, Mark KUPRAT, Harald SCHWARZ

《能源前沿（英文）》 2018年第12卷第4期页码 493-500 doi: 10.1007/s11708-018-0570-2

摘要： In the face of global warming and a scarcity of resources, future energy systems are urged to undergo a major and radical transformation. The recognition of the need to embrace renewable energy technologies and to move toward decarbonization has led to significant changes in the German energy generation, consumption and infrastructure. Ambitious German national plans to decrease carbon dioxide emissions on one side, and the unpredictable and volatile nature of renewable energy sources on the other side have elevated the importance of integrated energies in recent years. The deployment of integrated technologies as a solution to interlink various infrastructures creates opportunities for increasing the reliability of energy systems, minimizing environmental impacts and maximizing the share of renewable resources. This paper discusses the role of integrated energy systems in supporting of sustainable solutions for future energy transitions. Moreover, the reinforcement of this movement with the help of different technologies will be discussed and the development of integrated energy systems in Germany will be reviewed.

关键词： integrated energy renewable energies energy transition power-to-gas power-to-heat power-to-mobility energy storage

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基于状态空间法的铁路建设工程过程质量模型研究

鲁守东,周国华,陈海峰,赵国堂

《中国工程科学》 2014年第16卷第3期页码 64-69

摘要：

在ISO9000过程“输入-输出”模型下，过程质量概念很难得到正确的阐释。从过程的“白箱”理论出发，以铁路建设工程的基本作业单元6M1E为例，给出了过程质量概念的科学涵义及过程质量模型。指出基本作业单元系统的过程包括工艺自然过程、作业过程、管理过程；基本作业单元系统的过程质量取决于3个子过程之间的相互联系和相互作用，同时还受到外界扰动输入因素的影响。最后以现浇预应力砼连续箱梁施工过程为例，阐述了该理论在铁路建设工程质量管理中的具体应用。

关键词：铁路建设工程 “白箱”模型状态转移方程过程质量

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Octane compositions in sulfuric acid catalyzed isobutane/butene alkylation products: experimental and quantum chemistry studies

Lina Liang, Youzhi Liu, Weizhou Jiao, Qiaoling Zhang, Chao Zhang

《化学科学与工程前沿（英文）》 2021年第15卷第5期页码 1229-1242 doi: 10.1007/s11705-020-2030-x

摘要： Octanes in alkylation products obtained from industrial alkylation were studied by batch experiments. More than eight octane isomers were identified and quantified by gas chromatography-mass spectrometry. Based on a classic carbenium ion mechanism, the carbocation transition states in concentrated sulfuric acid catalyzed alkylation were investigated using quantum-chemical simulations and predicted the concentration and octane isomerization products including trimethylpentane and dimethylhexane as well as the formation of heavier compounds that resulted from the oligomerization of octane and butene. The agreement between model calculations and experimental data was quite satisfactory. Calculation results indicated that composition and content of trimethylpentanes in the alkylation products were 2,2,4-trimethylpentane>2,3,3-trimethylpentane>2,3,4-trimethylpentane>2,2,3-trimethylpentane whether the 2-butene or -butene acts as olefin. Heavier compounds in the alkylate were primarily formed by the oligomerization of dimethylhexane with 1-butene. Hopefully, the carbocation transition state models developed in this work will be useful for understanding the product distributions of octane in alkylation products.

关键词： sulfuric acid catalyzed alkylation carbocation reaction transition state octane compositions

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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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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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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