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700 m级钢管混凝土拱桥设计与建造可行性研究

郑皆连,王建军,牟廷敏,冯智,韩玉,秦大燕

《中国工程科学》 2014年 第16卷 第8期   页码 33-37

摘要:

以500 m级钢管混凝土拱桥的设计和成套施工技术为基础,对700 m级钢管混凝土拱桥的设计和建造技术进行可行性研究,确定总体设计和施工方案研究结果表明,建造700 m级的钢管混凝土拱桥已不存在技术门槛,综合考虑经济、安全等因素,是该跨径级别的强力竞争桥型之一,应尽早进行工程实践和推广。

关键词: 桥梁工程     700 m跨径级别     钢管混凝土拱桥     设计     建造    

700 °C 及以上蒸汽温度下先进USC发电厂用耐热材料的研究和开发 Review

Fujio Abe

《工程(英文)》 2015年 第1卷 第2期   页码 211-224 doi: 10.15302/J-ENG-2015031

摘要:

欧洲、美国、日本已开展蒸汽温度为700 °C 及以上的先进超超临界(A-USC) 发电厂用材料开发项目,以实现更高能效和低二氧化碳排放量。近年来中国、印度等也开展了上述项目的开发和研究。这些项目涉及采用镍基合金更换马氏体9%~12%Cr 钢以用于最高温度的锅炉和涡轮部件,从而在700 °C 及以上温度下提供充足的蠕变强度。

关键词: 镍基合金     9 %~12 % Cr 钢     蠕变强度     蠕变疲劳性质     焊缝     晶界     显微结构     &gamma     &prime     M23C6 碳化物    

Structure improvement and strength finite element analysis of VHP welded rotor of 700°C USC steam turbine

Jinyuan SHI,Zhicheng DENG,Yong WANG,Yu YANG

《能源前沿(英文)》 2016年 第10卷 第1期   页码 88-104 doi: 10.1007/s11708-015-0387-1

摘要: The optimized structure strength design and finite element analysis method for very high pressure (VHP) rotors of the 700°C ultra-super-critical (USC) steam turbine are presented. The main parameters of steam and the steam thermal parameters of blade stages of VHP welded rotors as well as the start and shutdown curves of the steam turbine are determined. The structure design feature, the mechanical models and the typical position of stress analysis of the VHP welded rotors are introduced. The steady and transient finite element analysis are implemented for steady condition, start and shutdown process, including steady rated condition, 110% rated speed, 120% rated speed, cold start, warm start, hot start, very hot start, sliding-pressure shutdown, normal shutdown and emergency shutdown, to obtain the temperature and stress distribution as well as the stress ratio of the welded rotor. The strength design criteria and strength analysis results of the welded rotor are given. The results show that the strength design of improved structure of the VHP welded rotor of the 700°C USC steam turbine is safe at the steady condition and during the transient start or shutdown process.

关键词: 700°C ultra-super-critical unit     steam turbine     very high pressure rotor     structure strength design     strength design criteria     finite element analysis    

三峡工程巨型水轮发电机组设计与实践

邵建雄,刘景旺,袁达夫

《中国工程科学》 2011年 第13卷 第7期   页码 104-110

摘要:

分析了三峡水轮发电机组设计中必须考虑的主要问题;总结了所进行的关键技术研究;通过关键技术问题研究,使得三峡水轮发电机组参数达到最优化。机组运行结果表明三峡水轮发电机组性能良好,能够长期安全、稳定、高效运行,从而有效地验证了对三峡巨型水轮发电机组的总体技术设计是科学合理的。

关键词: 三峡工程     700 MW级水电机组     单机容量     设计研究     运行稳定性     实践    

Cooling performance of grid-sheets for highly loaded ultra-supercritical steam turbines

Dieter BOHN , Robert KREWINKEL , Shuqing TIAN ,

《能源前沿(英文)》 2009年 第3卷 第3期   页码 313-320 doi: 10.1007/s11708-009-0036-7

摘要: In order to increase efficiency and achieve a further CO-reduction, the next generation of power plant turbines will have steam turbine inlet temperatures that are considerably higher than the current ones. The high pressure steam turbine inlet temperature is expected to be increased up to approximately 700°C with a live steam pressure of 30MPa. The elevated steam parameters in the high and intermediate pressure turbines can be encountered with Ni-base alloys, but this is a costly alternative associated with many manufacturing difficulties. Collaborative research centre 561 “Thermally Highly Loaded, Porous and Cooled Multi-Layer Systems for Combined Cycle Power Plants” at RWTH Aachen University proposes cooling the highly loaded turbines instead, as this would necessitate the application of far less Ni-base alloys. To protect the thermally highly loaded components, a sandwich material consisting of two thin face sheets and a core made from a woven wire mesh is used to cover the walls of the steam turbine casing. The cooling steam is led through the woven wire mesh between the two face sheets to achieve a cooling effect. The wire mesh provides the grid-sheet with structural rigidity under varying operating conditions.In the present work, the cooling performance of the grid-sheets will be investigated applying the conjugate heat transfer method to ultra-supercritical live and cooling steam conditions for a section of the cooling structure. The behaviour of the flow and the heat transfer in the grid-sheet will be analyzed in detail using a parameter variation. The numerical results should give a first prediction of the cooling performance under future operating conditions.

关键词: steam turbines     700&     deg     C-technology     numerical inverstigation     cooling    

Towards Cr(VI)-free anodization of aluminum alloys for aerospace adhesive bonding applications: A review

Abrahami, John M. M. de Kok, Herman Terryn, Johannes M. C. Mol

《化学科学与工程前沿(英文)》 2017年 第11卷 第3期   页码 465-482 doi: 10.1007/s11705-017-1641-3

摘要: For more than six decades, chromic acid anodizing (CAA) has been the central process in the surface pre-treatment of aluminum for adhesively bonded aircraft structures. Unfortunately, this electrolyte contains hexavalent chromium (Cr(VI)), a compound known for its toxicity and carcinogenic properties. To comply with the new strict international regulations, the Cr(VI)-era will soon have to come to an end. Anodizing aluminum in acid electrolytes produces a self-ordered porous oxide layer. Although different acids can be used to create this type of structure, the excellent adhesion and corrosion resistance that is currently achieved by the complete Cr(VI)-based process is not easily matched. This paper provides a critical overview and appraisal of proposed alternatives to CAA, including combinations of multiple anodizing steps, pre- and post anodizing treatments. The work is presented in terms of the modifications to the oxide properties, such as morphological features (e.g., pore size, barrier layer thickness) and surface chemistry, in order to evaluate the link between fundamental principles of adhesion and bond performance.

关键词: aluminum     Cr(VI)-free     surface pre-treatments     anodizing     adhesive bonding    

Scrutiny of non-linear differential equations Euler-Bernoulli beam with large rotational deviation by AGM

M. R. AKBARI,M. NIMAFAR,D. D. GANJI,M. M. AKBARZADE

《机械工程前沿(英文)》 2014年 第9卷 第4期   页码 402-408 doi: 10.1007/s11465-014-0316-8

摘要:

The kinematic assumptions upon which the Euler-Bernoulli beam theory is founded allow it to be extended to more advanced analysis. Simple superposition allows for three-dimensional transverse loading. Using alternative constitutive equations can allow for viscoelastic or plastic beam deformation. Euler-Bernoulli beam theory can also be extended to the analysis of curved beams, beam buckling, composite beams and geometrically nonlinear beam deflection. In this study, solving the nonlinear differential equation governing the calculation of the large rotation deviation of the beam (or column) has been discussed. Previously to calculate the rotational deviation of the beam, the assumption is made that the angular deviation of the beam is small. By considering the small slope in the linearization of the governing differential equation, the solving is easy. The result of this simplification in some cases will lead to an excessive error. In this paper nonlinear differential equations governing on this system are solved analytically by Akbari-Ganji’s method (AGM). Moreover, in AGM by solving a set of algebraic equations, complicated nonlinear equations can easily be solved and without any mathematical operations such as integration solving. The solution of the problem can be obtained very simply and easily. Furthermore, to enhance the accuracy of the results, the Taylor expansion is not needed in most cases via AGM manner. Also, comparisons are made between AGM and numerical method (Runge-Kutta 4th). The results reveal that this method is very effective and simple, and can be applied for other nonlinear problems.

关键词: AGM     critical load of columns     large deformations of beam     nonlinear differential equation    

ThMn12型永磁合金 Review

Hadjipanayis, A.M. Gabay, A.M. Schönhöbel, A. Martín-Cid, J.M. Barandiaran, D. Niarchos

《工程(英文)》 2020年 第6卷 第2期   页码 140-146 doi: 10.1016/j.eng.2018.12.011

摘要:

具有四方ThMn12型结构的富铁化合物有潜力满足当下人们对于高磁能积、工作温度为150~200 ℃的贫稀土永磁体的需求。尽管磁体制备技术的发展滞后于相关磁性材料的研究是正常的,但对于ThMn12型磁性材料而言,这种研究进展的差异非常显著。近年来,随着以含少量结构稳定元素(如SmFe11V或Sm0.8Zr0.2Fe9.2Co2.3Ti0.5)或者不含该类元素的材料(如SmFe9.6Co2.4薄膜)为基础所合成的具有优异内禀磁性化合物研究的突破,这一差距进一步扩大。在日益强大的理论计算的帮助下,人们对于理想的化合物的探寻从未停步。遗憾的是,基于聚合物键合填隙改性粉末的磁体的研究仍然处于边缘阶段。人们发现,引入镧(La)可以提高Sm(Fe,Ti)12中少数低熔点相的稳定性,从而首次使得液相烧结成为可能。然而,La金属的高反应活性会明显地破坏材料的矫顽力(Hc)。最初被抑制的ThMn12型相的可控结晶使得“块状”磁硬化成为可能,这不仅在Sm-Fe-V合金中可以实现(自20世纪90年代便为人所知),并且在添加La的(Ce,Sm)(Fe,Ti)12合金中也可以实现。然而,块状硬化所得的合金的性能仍然不能令人满意。机械化学合成的(Sm,Zr)(Fe,Si)12和(Sm,Zr)(Fe,Co,Ti)12粉末可能适合烧结成具有高强度的全致密磁体,尽管在此之前,两者都已开发出较高的各向异性,而后一种合金已开发出较高的矫顽力。

关键词: 永磁体,稀土永磁体,ThMn 12 结构    

Enhancing power transfer capability through flexible AC transmission system devices: a review

Fadi M. ALBATSH,Saad MEKHILEF,Shameem AHMAD,H. MOKHLIS,M. A. HASSAN

《信息与电子工程前沿(英文)》 2015年 第16卷 第8期   页码 658-678 doi: 10.1631/FITEE.1500019

摘要: Global demand for power has significantly increased, but power generation and transmission capacities have not increased proportionally with this demand. As a result, power consumers suffer from various problems, such as voltage and frequency instability and power quality issues. To overcome these problems, the capacity for available power transfer of a transmission network should be enhanced. Researchers worldwide have addressed this issue by using flexible AC transmission system (FACTS) devices. We have conducted a comprehensive review of how FACTS controllers are used to enhance the available transfer capability (ATC) and power transfer capability (PTC) of power system networks. This review includes a discussion of the classification of different FACTS devices according to different factors. The popularity and applications of these devices are discussed together with relevant statistics. The operating principles of six major FACTS devices and their application in increasing ATC and PTC are also presented. Finally, we evaluate the performance of FACTS devices in ATC and PTC improvement with respect to different control algorithms.

关键词: FACTS devices     Available transfer capability     Power transfer capability     Artificial intelligence    

Combined heat and power plant integrated with mobilized thermal energy storage (M-TES) system

M, Erik DAHLQUIST

《能源前沿(英文)》 2010年 第4卷 第4期   页码 469-474 doi: 10.1007/s11708-010-0123-9

摘要: Energy consumption for space and tap water heating in residential and service sectors accounts for one third of the total energy utilization in Sweden. District heating (DH) is used to supply heat to areas with high energy demand. However, there are still detached houses and sparse areas that are not connected to a DH network. In such areas, electrical heating or oil/pellet boilers are used to meet the heat demand. Extending the existing DH network to those spare areas is not economically feasible because of the small heat demand and the large investment required for the expansion. The mobilized thermal energy storage (M-TES) system is an alternative source of heat for detached buildings or sparse areas using industrial heat. In this paper, the integration of a combined heat and power (CHP) plant and an M-TES system is analyzed. Furthermore, the impacts of four options of the integrated system are discussed, including the power and heat output in the CHP plant. The performance of the M-TES system is likewise discussed.

关键词: Mobilized thermal energy system     district heating     thermal energy storage     combined heat and power     detached houses    

深碳观测计划——对地球内部碳的十年探索

Craig M. Schiffries, Andrea Johnson Mangum, Jennifer L. Mays, Michelle Hoon-Starr, Robert M. Hazen

《工程(英文)》 2019年 第5卷 第3期   页码 372-378 doi: 10.1016/j.eng.2019.03.004

RNA m6A modification and its function in diseases

null

《医学前沿(英文)》 2018年 第12卷 第4期   页码 481-489 doi: 10.1007/s11684-018-0654-8

摘要:

N6-methyladenosine (m6A) is the most common post-transcriptional RNA modification throughout the transcriptome, affecting fundamental aspects of RNA metabolism. m6A modification could be installed by m6A “writers” composed of core catalytic components (METTL3/METTL14/WTAP) and newly defined regulators and removed by m6A “erasers” (FTO and ALKBH5). The function of m6A is executed by m6A “readers” that bind to m6A directly (YTH domain-containing proteins, eIF3 and IGF2BPs) or indirectly (HNRNPA2B1). In the past few years, advances in m6A modulators (“writers,” “erasers,” and “readers”) have remarkably renewed our understanding of the function and regulation of m6A in different cells under normal or disease conditions. However, the mechanism and the regulatory network of m6A are still largely unknown. Moreover, investigations of the m6A physiological roles in human diseases are limited. In this review, we summarize the recent advances in m6A research and highlight the functional relevance and importance of m6A modification in in vitro cell lines, in physiological contexts, and in cancers.

关键词: RNA modification     m6A     immunity     cancer     epigenetics    

Velocity gradient elasticity for nonlinear vibration of carbon nanotube resonators

Hamid M. SEDIGHI, Hassen M. OUAKAD

《结构与土木工程前沿(英文)》 2020年 第14卷 第6期   页码 1520-1530 doi: 10.1007/s11709-020-0672-x

摘要: In this study, for the first time, we investigate the nonlocality superimposed to the size effects on the nonlinear dynamics of an electrically actuated single-walled carbon-nanotube-based resonator. We undertake two models to capture the nanostructure nonlocal size effects: the strain and the velocity gradient theories. We use a reduced-order model based on the differential quadrature method (DQM) to discretize the governing nonlinear equation of motion and acquire a discretized-parameter nonlinear model of the system. The structural nonlinear behavior of the system assuming both strain and velocity gradient theories is investigated using the discretized model. The results suggest that nonlocal and size effects should not be neglected because they improve the prediction of corresponding dynamic amplitudes and, most importantly, the critical resonant frequencies of such nanoresonators. Neglecting these effects may impose a considerable source of error, which can be amended using more accurate modeling techniques.

关键词: velocity gradient elasticity theory     nanotube resonators     differential-quadrature method     nonlinear vibration    

Application of statistical design for the production of inulinase by

M. DILIPKUMAR, M. RAJASIMMAN, N. RAJAMOHAN

《化学科学与工程前沿(英文)》 2011年 第5卷 第4期   页码 463-470 doi: 10.1007/s11705-011-1112-1

摘要: A Plackett-Burman design was employed for screening 18 nutrient components for the production of inulinase using sp. and pressmud as the substrate via solid-state fermentation (SSF). From the experiments, three nutrients viz. yeast extract, FeSO ·7H O, and NH NO were found to be the most significant components. Hence these three components were selected and optimized using Response Surface Methodology (RSM). The optimum conditions are: yeast extract 0.00274 g/gds, FeSO ·7H O 0.00011 g/gds and NH NO 0.00772 g/gds. The effect of the substrate concentration and initial moisture content were also studied. A substrate concentration of 12 g and an initial moisture content of 65% are optimum for the maximum production of inulinase (89 U/gds).

关键词: inulinase     pressmud     Response Surface Methodology (RSM)     streptomyces sp    

Special issue: Manufacturing engineering management

Shanlin YANG, Panos M. PARDALOS, Xinbao LIU

《工程管理前沿(英文)》 2018年 第5卷 第4期   页码 417-419 doi: 10.15302/J-FEM-2018209

摘要:

标题 作者 时间 类型 操作

700 m级钢管混凝土拱桥设计与建造可行性研究

郑皆连,王建军,牟廷敏,冯智,韩玉,秦大燕

期刊论文

700 °C 及以上蒸汽温度下先进USC发电厂用耐热材料的研究和开发

Fujio Abe

期刊论文

Structure improvement and strength finite element analysis of VHP welded rotor of 700°C USC steam turbine

Jinyuan SHI,Zhicheng DENG,Yong WANG,Yu YANG

期刊论文

三峡工程巨型水轮发电机组设计与实践

邵建雄,刘景旺,袁达夫

期刊论文

Cooling performance of grid-sheets for highly loaded ultra-supercritical steam turbines

Dieter BOHN , Robert KREWINKEL , Shuqing TIAN ,

期刊论文

Towards Cr(VI)-free anodization of aluminum alloys for aerospace adhesive bonding applications: A review

Abrahami, John M. M. de Kok, Herman Terryn, Johannes M. C. Mol

期刊论文

Scrutiny of non-linear differential equations Euler-Bernoulli beam with large rotational deviation by AGM

M. R. AKBARI,M. NIMAFAR,D. D. GANJI,M. M. AKBARZADE

期刊论文

ThMn12型永磁合金

Hadjipanayis, A.M. Gabay, A.M. Schönhöbel, A. Martín-Cid, J.M. Barandiaran, D. Niarchos

期刊论文

Enhancing power transfer capability through flexible AC transmission system devices: a review

Fadi M. ALBATSH,Saad MEKHILEF,Shameem AHMAD,H. MOKHLIS,M. A. HASSAN

期刊论文

Combined heat and power plant integrated with mobilized thermal energy storage (M-TES) system

M, Erik DAHLQUIST

期刊论文

深碳观测计划——对地球内部碳的十年探索

Craig M. Schiffries, Andrea Johnson Mangum, Jennifer L. Mays, Michelle Hoon-Starr, Robert M. Hazen

期刊论文

RNA m6A modification and its function in diseases

null

期刊论文

Velocity gradient elasticity for nonlinear vibration of carbon nanotube resonators

Hamid M. SEDIGHI, Hassen M. OUAKAD

期刊论文

Application of statistical design for the production of inulinase by

M. DILIPKUMAR, M. RAJASIMMAN, N. RAJAMOHAN

期刊论文

Special issue: Manufacturing engineering management

Shanlin YANG, Panos M. PARDALOS, Xinbao LIU

期刊论文