资源类型

期刊论文 328

会议视频 1

年份

2023 28

2022 19

2021 21

2020 15

2019 11

2018 7

2017 19

2016 12

2015 10

2014 12

2013 23

2012 10

2011 15

2010 21

2009 12

2008 29

2007 38

2006 7

2005 5

2004 3

展开 ︾

关键词

温度 3

温度控制 3

高温气冷堆 3

低温SOFC 2

大气温度 2

技术路线 2

核能 2

模糊控制 2

温度分布 2

(美国) 核管理委员会 1

10kV高压电力电缆 1

Au/Ti双功能催化剂 1

CCD 1

CCD影像 1

Cu(In 1

D1 turnover / photoinhibition / photoprotection / photosynthesis / tomato / xanthophyll cycle 1

Ga)Se2 1

H2有效利用率 1

ISO标准火灾实验系统 1

展开 ︾

检索范围：

排序： 展示方式：

Steady-state thermal-hydraulic analysis of SCWR assembly

LIU Xiaojing, CHENG Xu

《能源前沿（英文）》 2008年 第2卷 第4期   页码 475-478 doi: 10.1007/s11708-008-0093-3

摘要： Among the six gen-IV reactor concepts recommended by the gen-IV international forum (GIF), supercritical water-cooled reactor (SCWR), the only reactor with water as coolant, achieves a high thermal efficiency and, subsequently, has economic advantages over the existing reactors due to its high outlet temperature. A thermal-hydraulic analysis of the SCWR assembly is performed in this paper using the modified COBRA-IV code. Two approaches to reduce the hot channel factor are investigated: decreasing the moderator mass flow and increasing the thermal resistance between moderator channel and its adjacent sub-channels. It is shown that heat transfer deterioration cannot be avoided in SCWR fuel assembly. It is, therefore, highly required to calculate the cladding temperature accurately and to preserve the fuel rod cladding integrity under heat transfer deterioration conditions.

关键词： cladding temperature     assembly     temperature     coolant     resistance    

HTML PDF 收藏

Process improvement in laser hot wire cladding for martensitic stainless steel based on the Taguchi method

Zilin HUANG,Gang WANG,Shaopeng WEI,Changhong LI,Yiming RONG

《机械工程前沿（英文）》 2016年 第11卷 第3期   页码 242-249 doi: 10.1007/s11465-016-0397-7

摘要：

Laser hot wire cladding, with the prominent features of low heat input, high energy efficiency, and high precision, is widely used for remanufacturing metal parts. The cladding process, however, needs to be improved by using a quantitative method. In this work, volumetric defect ratio was proposed as the criterion to describe the integrity of forming quality for cladding layers. Laser deposition experiments with FV520B, one of martensitic stainless steels, were designed by using the Taguchi method. Four process variables, namely, laser power (P), scanning speed (Vs), wire feed rate (Vf), and wire current (I), were optimized based on the analysis of signal-to-noise (S/N) ratio. Metallurgic observation of cladding layer was conducted to compare the forming quality and to validate the analysis method. A stable and continuous process with the optimum parameter combination produced uniform microstructure with minimal defects and cracks, which resulted in a good metallurgical bonding interface.

关键词： process optimization     Taguchi method     signal-to-noise (S/N) ratio     volumetric defect ratio     laser hot wire cladding    

HTML PDF 收藏

Construction of nitrogen-doped carbon cladding LiMnO film electrode with enhanced stability for electrochemically

《化学科学与工程前沿（英文）》 2023年 第17卷 第12期   页码 2050-2060 doi: 10.1007/s11705-023-2343-7

摘要： Reducing the dissolution of Mn from LiMn2O4 (LMO) and enhancing the stability of film electrodes are critical and challenging for Li+ ions selective extraction via electrochemically switched ion exchange technology. In this work, we prepared a nitrogen-doped carbon cladding LMO (C-N@LMO) by polymerization of polypyrrole and high-temperature annealing in the N2 gas to achieve the above purpose. The modified C-N@LMO film electrode exhibited lower Mn dissolution and better cyclic stability than the LMO film electrode. The dissolution ratio of Mn from the C-N@LMO film electrode decreased by 42% compared to the LMO film electrode after 10 cycles. The cladding layer not only acted as a protective layer but also functioned as a conductive shell, accelerating the migration rate of Li+ ions. The intercalation equilibrium time of the C-N@LMO film electrode reached within an hour during the extraction of Li+ ions, which was 33% less compared to the pure LMO film electrode. Meanwhile, the C-N@LMO film electrode retained evident selectivity toward Li+ ions, and the separation factor was 118.38 for Li+ toward Mg2+ in simulated brine. Therefore, the C-N@LMO film electrode would be a promising candidate for the recovery of Li+ ions from salt lakes.

关键词： LiMn2O4     lithium extraction     surface coating     cyclic stability     Mn dissolution    

HTML PDF 收藏

Influence of the field humiture environment on the mechanical properties of 316L stainless steel repaired with Fe314

Lianzhong ZHANG, Dichen LI, Shenping YAN, Ruidong XIE, Hongliang QU

《机械工程前沿（英文）》 2018年 第13卷 第4期   页码 513-519 doi: 10.1007/s11465-018-0503-0

摘要：

The mechanical properties of 316L stainless steel repaired with Fe314 under different temperatures and humidities without inert gas protection were studied. Results indicated favorable compatibility between Fe314 and 316L stainless steel. The average yield strength, tensile strength, and sectional contraction percentage were higher in repaired samples than in 316L stainless steel, whereas the elongation rate was slightly lower. The different conditions of humiture environment on the repair sample exerted minimal influence on tensile and yield strengths. The Fe314 cladding layer was mainly composed of equiaxed grains and mixed with randomly oriented columnar crystal and tiny pores or impurities in the tissue. Results indicated that the hardness value of Fe314 cladding layer under different humiture environments ranged within 419–451.1 HV0.2. The field humiture environment also showed minimal impact on the average hardness of Fe314 cladding layers. Furthermore, 316L stainless steel can be repaired through laser cladding by using Fe314 powder without inert gas protection under different temperatures and humidity environments.

关键词： laser cladding     repaired performance     tensile strength     temperature and humidity environment    

HTML PDF 收藏

Hybrid forming mechanism of patternless casting and laser cladding

Zhongde SHAN, Fuzhen SUN, Yang LIU

《机械工程前沿（英文）》 2019年 第14卷 第4期   页码 393-401 doi: 10.1007/s11465-019-0550-1

摘要： In accordance with the requirement of manufacturing dies quickly and economically, a hybrid forming method of stamping dies for automobile panels is proposed. The method combines digital patternless casting and high-power laser cladding. An experimental study is conducted on the hybrid forming process and its trial production and application in the manufacturing of stamping dies for typical panels. Results prove that the laser cladding layer exceeds HRC60 (Rockwell hardness) and thus meets the production efficiency requirement of automobile dies. The rate of defects is well controlled. Compared with traditional technology, this technology has remarkable advantages and advancement.

关键词： patternless casting     laser cladding     hybrid forming     rapid tooling    

HTML PDF 收藏

The Application and the Prospect of Remanufacturing Technologies in the Metallurgical Industry

Jie Xiong,Jian-cheng Fan,Jv Yuan

《工程管理前沿（英文）》 2016年 第3卷 第2期   页码 165-170 doi: 10.15302/J-FEM-2016023

摘要： Metallurgical equipment is subjected to severe working conditions and the components suffer from various types of physical damages such as abrasion, corrosion and crack. Advanced surface engineering technologies and resistant coatings on the damaged surface can improve surface properties, extend service lives, reduce maintenance costs and improve product quality in the metallurgical industry. This paper introduces remanufacturing technologies, including electroplating, overlaying welding, thermal spraying and laser surface cladding and their applications in the metallurgical industry, and analyzes the development tendency and prospect of remanufacturing technologies.

关键词： remanufacturing technology     electroplating     overlaying welding     thermal spraying     laser surface cladding    

HTML PDF 收藏

Wind tunnel test study on the wind pressure coefficient of claddings of high-rise buildings

Yong QUAN, Yi LIANG, Fei WANG, Ming GU

《结构与土木工程前沿（英文）》 2011年 第5卷 第4期   页码 518-524 doi: 10.1007/s11709-011-0128-4

摘要： The area-averaged most unfavorable wind pressure coefficients (MUWPCs) on various regions of building surfaces and the influence of the side ratio and the terrain category were studied based on wind tunnel test data of scale models of typical high-rise buildings with rectangular cross-sections. The negative area-averaged MUWPCs in the middle-height edge areas generally increased with an increasing / side ratio. The area-averaged MUWPCs can be well fitted with a function of the average area reduced by the square of the building depth, . In addition, no unique pattern was found for the effect of the terrain category on the MUWPCs.

关键词： side ratio     area-averaged pressure coefficients     cladding     terrain category    

HTML PDF 收藏

激光表面改性技术发展研究

张群莉,王梁,梅雪松,姚建华

《中国工程科学》 2020年 第22卷 第3期   页码 71-77 doi: 10.15302/J-SSCAE-2020.03.010

摘要：

激光表面改性技术利用高能量密度的激光束对零部件局部易损易耗区域进行快速处理，获得材料表面所需性能，进而大幅延长零部件使用寿命，已在航空航天、石油化工、能源、交通、冶金等领域获得应用。本文针对激光冲击强化、激光淬火、激光熔覆3 种典型的激光表面改性技术，梳理了相应技术特点及国内外应用现状，凝练我国相关技术领域面临的差距与问题，总结激光表面改性技术的重点发展方向：专用合金材料制备、多能场激光复合表面改性、面向现场的激光再制造、激光冲击强化控形控性、激光表面改性智能化、激光表面微结构化。从政府引导、国产化创新、产业链完善、质量评价标准体系、人才培养等方面提出发展建议，以期为我国激光表面改性技术发展提供参考借鉴。

关键词： 激光表面改性     冲击强化     淬火     熔覆     发展趋势    

HTML PDF 收藏

Emerging challenges to structural integrity technology for high-temperature applications

TU Shantung

《机械工程前沿（英文）》 2007年 第2卷 第4期   页码 375-387 doi: 10.1007/s11465-007-0066-y

摘要： Structural integrity technology has been widely used with great success for the design, manufacture and failure prevention of modern constructions such as chemical and petrochemical plants, power generation and energy conversion systems, as well as space and oceanic exploration. The modern needs of structural integrity technology are largely attributed to the increase of service temperature of the structures that results in the efficiency improvement in energy conversion and chemical processing technologies. Besides the needs arising from large-scale high-temperature plants, the high tech developments, such as micro chemo-mechanical systems and high-power electronics, provide new challenges to structural integrity technology. The present paper summarizes the recent technical progresses in large process plants and the aviation industry, micro chemo-mechanical systems, fuel cells, high-temperature electronics, and packaging and coating technologies. The state-of-the-art of structural integrity technology for high temperature applications is reviewed. Suggestions are provided for the improvement of current design and assessment methods.

关键词： manufacture     aviation industry     conversion     petrochemical     temperature    

HTML PDF 收藏

Effects of temperature on pyrolysis products of oil sludge

LIU Jianguo, SONG Wei, NIE Yongfeng

《环境科学与工程前沿（英文）》 2008年 第2卷 第1期   页码 8-14 doi: 10.1007/s11783-008-0030-z

摘要： Temperature is the determining factor of pyrolysis, which is one of the alternative technologies for oil sludge treatment. The effects of final operating temperature ranging from 350 to 550°C on pyrolysis products of oil sludge were studied in an externally-heating fixed bed reactor. With an increase of temperature, the mass fraction of solid residues, liquids, and gases in the final product is 67.00%–56.00%, 25.60%–32.35%, and 7.40%–11.65%, and their corresponding heat values are 34.4–13.8 MJ/kg, 44.41–46.6 MJ/kg, and 23.94–48.23 MJ/Nm, respectively. The mass and energy tend to shift from solid to liquid and gas phase (especially to liquid phase) during the process, and the optimum temperature for oil sludge pyrolysis is 500°C. The liquid phase is mainly composed of alkane and alkene (C–C), and the gas phase is dominantly HC and H.

关键词： sludge treatment     corresponding     Temperature     liquid     process    

HTML PDF 收藏

Phase separation time/temperature dependence of thermoplastics-modified thermosetting systems

ZHANG Xiujuan, XU Yuanze, YI Xiaosu

《化学科学与工程前沿（英文）》 2008年 第2卷 第3期   页码 276-285 doi: 10.1007/s11705-008-0057-5

摘要： The cure-induced phase separation processes of various thermoplastics(TP)-modified thermosetting systems which show upper critical solution temperature (UCST) or lower critical solution temperature (LCST) were studied with emphasis on the temperature dependency of the phase separation time and its potential application in the cure time-temperature processing window. We found that the phase separation time/temperature relationship follows the simple Arrhenius equation. The cure-induced phase separation activation energy (ps) generated from the linear fitting of the Arrhenius equation is irrelevant to the detection means of phase separation time. We also found that (ps) is insensitive to TP content, TP molecular weight and curing rate, but it changes with the cure reaction kinetics and the chemical environment of the systems. With the established phase separation time-temperature dependence relation, we can easily establish the whole cure time-temperature transformation (TTT) diagram with morphology information which is a useful map for the TP/TS composites processing industry.

关键词： separation time-temperature     temperature dependency     cure-induced     separation activation     temperature    

HTML PDF 收藏

Elevated temperature creep model of parallel wire strands

《结构与土木工程前沿（英文）》   页码 1060-1071 doi: 10.1007/s11709-023-0981-y

摘要： Parallel wire strands (PWSs), which are widely used in prestressed steel structures, are typically in high-stress states. Under fire conditions, significant creep effects occur, reducing the prestress and influencing the mechanical behavior of PWSs. As there is no existing approach to analyze their creep behavior, this study experimentally investigated the elevated temperature creep model of PWSs. A charge-coupled camera system was incorporated to accurately obtain the deformation of the specimen during the elevated temperature creep test. It was concluded that the temperature level had a more significant effect on the creep strain than the stress level, and 450 °C was the key segment point where the creep rate varied significantly. By comparing the elevated temperature creep test results for PWSs and steel strands, it was found that the creep strain of PWSs was lower than that of steel strands at the same temperature and stress levels. The parameters in the general empirical formula, the Bailey–Norton model, and the composite time-hardening model were fitted based on the experimental results. By evaluating the accuracy and form of the models, the composite time-hardening model, which can simultaneously consider temperature, stress, and time, is recommended for use in the fire-resistance design of pre-tensioned structures with PWSs.

关键词： parallel wire strands     experimental study     elevated temperature creep model    

HTML PDF 收藏

Field test on temperature field and thermal stress for prestressed concrete box-girder bridge

Baoguo CHEN, Rui DING, Junjie ZHENG, Shibiao ZHANG

《结构与土木工程前沿（英文）》 2009年 第3卷 第2期   页码 158-164 doi: 10.1007/s11709-009-0002-9

摘要： A field test was conducted to investigate the distribution of temperature field and the variation of thermal stress for a prestressed concrete (PC) box-girder bridge. The change of hydration heat temperature consists of four periods: temperature rising period, constant temperature period, rapid temperature fall period and slow temperature fall period. The peak value of hydration heat temperature increases with the increasing casting temperature of concrete; the relation between them is approximately linear. According to field tests, the thermal stress incurred by hydration heat may induce temperature cracks on the PC box-girder. Furthermore, the nonlinear distribution of temperature gradient and the fluctuation of thermal stress induced by exposure to sunlight were also obtained based on continuous in-situ monitoring. Such results show that the prevailing Chinese Code (2004) is insufficient since it does not take into account the temperature gradient of the bottom slab. Finally, some preventive measures against temperature cracks were proposed based on related studies. The conclusions can provide valuable reference for the design and construction of PC box-girder bridges.

关键词： box-girder bridge     field test     hydration heat     temperature field     temperature gradient     thermal stress    

HTML PDF 收藏

A review of low-temperature plasma-assisted machining: from mechanism to application

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0734-y

摘要： Materials with high hardness, strength or plasticity have been widely used in the fields of aviation, aerospace, and military, among others. However, the poor machinability of these materials leads to large cutting forces, high cutting temperatures, serious tool wear, and chip adhesion, which affect machining quality. Low-temperature plasma contains a variety of active particles and can effectively adjust material properties, including hardness, strength, ductility, and wettability, significantly improving material machinability. In this paper, we first discuss the mechanisms and applications of low-temperature plasma-assisted machining. After introducing the characteristics, classifications, and action mechanisms of the low-temperature plasma, we describe the effects of the low-temperature plasma on different machining processes of various difficult-to-cut materials. The low-temperature plasma can be classified as hot plasma and cold plasma according to the different equilibrium states. Hot plasma improves material machinability via the thermal softening effect induced by the high temperature, whereas the main mechanisms of the cold plasma can be summarized as chemical reactions to reduce material hardness, the hydrophilization effect to improve surface wettability, and the Rehbinder effect to promote fracture. In addition, hybrid machining methods combining the merits of the low-temperature plasma and other energy fields like ultrasonic vibration, liquid nitrogen, and minimum quantity lubrication are also described and analyzed. Finally, the promising development trends of low-temperature plasma-assisted machining are presented, which include more precise control of the heat-affected zone in hot plasma-assisted machining, cold plasma-assisted polishing of metal materials, and further investigations on the reaction mechanisms between the cold plasma and other materials.

关键词： low-temperature plasma     difficult-to-cut material     machinability     hydrophilization effect     Rehbinder effect    

HTML PDF 收藏

Real-time tool condition monitoring method based on temperature measurement and artificial neural network

《机械工程前沿（英文）》 doi: 10.1007/s11465-021-0661-3

摘要： Tool failures in machining processes often cause severe damages of workpieces and lead to large quantities of loss, making tool condition monitoring an important, urgent issue. However, problems such as practicability still remain in actual machining. Here, a real-time tool condition monitoring method integrated in an in situ fiber optic temperature measuring apparatus is proposed. A thermal simulation is conducted to investigate how the fluctuating cutting heats affect the measuring temperatures, and an intermittent cutting experiment is carried out, verifying that the apparatus can capture the rapid but slight temperature undulations. Fourier transform is carried out. The spectrum features are then selected and input into the artificial neural network for classification, and a caution is given if the tool is worn. A learning rate adaption algorithm is introduced, greatly reducing the dependence on initial parameters, making training convenient and flexible. The accuracy stays 90% and higher in variable argument processes. Furthermore, an application program with a graphical user interface is constructed to present real-time results, confirming the practicality.

关键词： tool condition monitoring     cutting temperature     neural network     learning rate adaption    

HTML PDF 收藏

标题 作者 时间 类型 操作

Steady-state thermal-hydraulic analysis of SCWR assembly

LIU Xiaojing, CHENG Xu

期刊论文

Process improvement in laser hot wire cladding for martensitic stainless steel based on the Taguchi method

Zilin HUANG,Gang WANG,Shaopeng WEI,Changhong LI,Yiming RONG

期刊论文

Construction of nitrogen-doped carbon cladding LiMnO film electrode with enhanced stability for electrochemically

期刊论文

Influence of the field humiture environment on the mechanical properties of 316L stainless steel repaired with Fe314

Lianzhong ZHANG, Dichen LI, Shenping YAN, Ruidong XIE, Hongliang QU

期刊论文

Hybrid forming mechanism of patternless casting and laser cladding

Zhongde SHAN, Fuzhen SUN, Yang LIU

期刊论文

The Application and the Prospect of Remanufacturing Technologies in the Metallurgical Industry

Jie Xiong,Jian-cheng Fan,Jv Yuan

期刊论文

Wind tunnel test study on the wind pressure coefficient of claddings of high-rise buildings

Yong QUAN, Yi LIANG, Fei WANG, Ming GU

期刊论文

激光表面改性技术发展研究

张群莉,王梁,梅雪松,姚建华

期刊论文

Emerging challenges to structural integrity technology for high-temperature applications

TU Shantung

期刊论文

Effects of temperature on pyrolysis products of oil sludge

LIU Jianguo, SONG Wei, NIE Yongfeng

期刊论文

Phase separation time/temperature dependence of thermoplastics-modified thermosetting systems

ZHANG Xiujuan, XU Yuanze, YI Xiaosu

期刊论文

Elevated temperature creep model of parallel wire strands

期刊论文

Field test on temperature field and thermal stress for prestressed concrete box-girder bridge

Baoguo CHEN, Rui DING, Junjie ZHENG, Shibiao ZHANG

期刊论文

A review of low-temperature plasma-assisted machining: from mechanism to application

期刊论文

Real-time tool condition monitoring method based on temperature measurement and artificial neural network

期刊论文