Search | Engineering

订阅投稿

首页工程期刊工程焦点工程成就工程前沿关于我们 English

资源类型

期刊论文 467

会议视频 6

年份

2024 2

2023 32

2022 35

2021 37

2020 30

2019 22

2018 23

2017 20

2016 19

2015 21

2014 19

2013 19

2012 19

2011 19

2010 20

2009 23

2008 41

2007 29

2006 8

2005 4

展开︾

关键词

DX桩 2

人工智能 2

力学性能 2

单边直线感应电机 2

多晶硅 2

数值模拟 2

碳中和 2

ADV 1

CCUS 1

CFD 1

CO₂利用 1

COVID-19 1

Cas12a 1

Chebyshev多项式 1

Colebrook隐式方程 1

Cu(In 1

DNA结构 1

Ga)Se₂ 1

HY-2 卫星 1

展开︾

检索范围：

排序：展示方式：

Exhaust hood for steam turbines-single-flow arrangement

Michal HOZNEDL , Ladislav TAJC , Jaroslav KREJCIK , Lukas BEDNAR , Kamil SEDLAK , Jiri LINHART ,

《能源前沿（英文）》 2009年第3卷第3期页码 321-329 doi: 10.1007/s11708-009-0039-4

摘要： In the past, increased attention was given to the development of an optimal shape for the inlet part of LP turbine casings in SKODA POWER. A double-flow design is typically used for high power output turbines. An optimized shape for the internal diffuser has been found, which transforms the kinetic energy of steam into increased pressure, thus effectively increasing the thermodynamic efficiency of the stage. Some conclusions have been drawn from laboratory experiments, others derived directly from on-site measurements at power plants. The conclusions from the development of double-flow turbines form the basis for the design of the single-flow turbine arrangement. Single-flow design is typically used for lower output turbines. There are still some limitations in applying this arrangement. The designer needs to resolve the bearing position and how to ensure access to them. Reinforcing the ribs and supports are used, therefore, to ensure the rigidity of the entire casing. The optimization of the single-flow diffuser shape is therefore the subject of the study presented below.

关键词： exhaust hood steam turbines single-flow arrangement

HTML PDF 收藏

Flow characteristics of single-phase flow in narrow annular channels

ZENG Heyi, SU Guanghui, JIA Dounan

《能源前沿（英文）》 2008年第2卷第4期页码 466-470 doi: 10.1007/s11708-008-0101-7

摘要： The characteristics of single-phase flow in narrow annular channels were analyzed and theoretical model was proposed. Based on the present model, the theoretical calculation was performed to predict the flow characteristics for the developed flow in narrow annuli with the gap sizes of 1.0, 1.5 and 2.0 mm, respectively. The results were in good agreement with the experimental data. In addition, the gap size of narrow annuli has great impact upon the flow characteristics. The decrease of gap size reduces friction factor. The higher the Reynolds number, the more remarkable the effect of gap size upon friction coefficient during single-phase flowing through narrow annular channels. The effect of gap size upon friction coefficient is dependent on the Reynolds number, and will decrease with the decrease of the Reynolds number.

关键词： narrow annuli remarkable mm developed friction

HTML PDF 收藏

Simulation of cottonseed cake melt flow in metering zone of a single screw extruder

Hong HE, Jianguo ZHOU,

《化学科学与工程前沿（英文）》 2010年第4卷第3期页码 263-269 doi: 10.1007/s11705-009-0276-4

摘要： Research on the extrusion of natural polymers (food, feed, etc.) is relatively new due to the complex physicochemical transformations of raw materials, although plastics melt conveying and transport have been well studied. The structure and composition, rheological behavior as well as extrusion processing of natural polymer are much more complicated. In this study, a quasi-three-dimensional (3D) fluid flow model for non-Newtonian, non-isothermal and undeveloped temperature was developed, the model prediction being in reasonably good agreement with the experiment. Results show that the influence of moisture content, among other process variables, is the most significant, followed by screw speed. Some interaction exists between these two variables and the screw speed effect becomes marginal at high moisture contents. In addition, viscosity change in the channel was studied.

关键词： quasi-three-dimensional rheological viscosity processing influence

HTML PDF 收藏

Two-stage scheduling on batch and single machines with limited waiting time constraint

Zhongshun SHI, Zewen HUANG, Leyuan SHI

《工程管理前沿（英文）》 2017年第4卷第3期页码 368-374 doi: 10.15302/J-FEM-2017034

摘要： This study addresses the problem of two-stage scheduling on batch and single machines with limited waiting time constraint; thus, the makespan is minimized. A mixed-integer linear programming model is proposed for this problem. Three tight lower bounds and a heuristic algorithm are developed. The worst-case performance of the proposed algorithm is discussed. A hybrid differential evolution algorithm is also developed to improve the solution quantity. Numerical results show that the hybrid algorithm is capable of obtaining high-quality solutions and exhibits a competitive performance

关键词： batch machine flow shop makespan limited waiting time

HTML PDF 收藏

Chebyshev多项式在锚链分析中的应用

滕斌,郝春玲,韩凌

《中国工程科学》 2005年第7卷第1期页码 21-26

摘要：

依据水流作用下锚链的数值分析模型，提出了应用Chebyshev多项式拟合建立锚链张力与锚链顶端位置函数关系的近似方法，该锚链函数多项式可方便地用于波浪与锚泊结构物相互作用的实时模拟中。计算中按静水和有流两种情况，应用二维和三维Chebyshev多项式，建立了锚链顶端水平和垂向拉力与锚链顶端水平、垂向位置，及水流速度的函数关系。锚链分析模型采用分段外推－校正方法计算，在无流、均质锚链情况下，计算结果与解析解完全吻合。

关键词：锚链张力锚链位移 Chebyshev多项式

HTML PDF 收藏

Conserved gene arrangement in the mitochondrial genomes of barklouse families Stenopsocidae and Psocidae

Xiaochen LIU, Hu LI, Yao CAI, Fan SONG, John-James WILSON, Wanzhi CAI

《农业科学与工程前沿（英文）》 2017年第4卷第3期页码 358-365 doi: 10.15302/J-FASE-2017158

摘要： Substantial variation in gene organization and arrangement has been reported for sequenced mitochondrial (mt) genomes from the suborders of the insect order Psocoptera. In this study we sequenced the complete mt genome of , the first representative of the family Stenopsocidae from the suborder Psocomorpha. Relative to the ancestral pattern, rearrangements of a protein-coding gene ( ) and five tRNA genes ( , , , , ) were found. This pattern was similar to that of two barklice from the family Psocidae, with the exception of the translocation of , and Based on comparisons of pairwise breakpoint distances of gene rearrangements, gene number and chromosome number, it was concluded that mt genomes of Stenopsocidae and Psocidae share a relatively conserved pattern of gene rearrangements; mt genomes within the Psocomorpha have been generally stable over long evolutionary history; and mt gene rearrangement has been substantially faster in the booklice (suborder Troctomorpha) than in the barklice (suborders Trogiomorpha and Psocomorpha). It is speculated that the change of life history and persistence of unusual reproductive systems with maternal inheritance contributed to the contrasting rates in mt genome evolution between the barklice and booklice.

关键词： gene rearrangement mitochondrial genome Psocoptera Stenopsocidae TDRL model

HTML PDF 收藏

集成产品开发规划的任务调度

鲁建厦,陈呈频,兰秀菊,陈勇,谢列卫

《中国工程科学》 2004年第6卷第5期页码 56-60

摘要：

在阐述集成产品开发（IPD）任务特点的基础上，研究了集成产品开发任务的耦合性和层次性，建立了分层分布式规划的策略，并引入代价矩阵概念，给出了任务调度模型和相应的匈牙利算法，并用实例演示了计算过程。

关键词：集成产品开发任务调度过程规划目标决策

HTML PDF 收藏

Alluvial channel hydrodynamics around tandem piers with downward seepage

Rutuja CHAVAN, Wenxin HUAI, Bimlesh KUMAR

《结构与土木工程前沿（英文）》 2020年第14卷第6期页码 1445-1461 doi: 10.1007/s11709-020-0648-x

摘要： In this paper, we report the turbulent flow structures and the scour geometry around two piers with different diameters. An experiment was conducted on a non-uniform sand bed with two types of tandem arrangements, namely, pier (T1) with a 75 mm front and 90 mm rear, and pier (T2) with a 90 mm front and 75 mm rear, with and without-seepage flows, respectively. A strong wake region was observed behind the piers, but the vortex strength diminished with downward seepage. Streamwise velocity was found to be maximum near the bed downstream of the piers and at the edge of the scour hole upstream of the piers. Quadrant analysis was used to recognize the susceptible region for sediment entrainment and deposition. Upstream of the piers near the bed, the moments, turbulent kinetic energy (TKE), and TKE fluxes were found to decrease with downward seepage, in contrast to those in a plane mobile bed without piers. The reduction percentages of scour depth at the rear pier compared with the front one were approximately 40% for T1 and 60% for T2. Downward seepage also resulted in restrained growth of scouring with time.

关键词： scour seepage Strouhal number tandem arrangement turbulent characteristics

HTML PDF 收藏

高速单像素成像技术原理及应用 Review

Qiang GUO, Yu-xi WANG, Hong-wei CHEN, Ming-hua CHEN, Si-gang YANG, Shi-zhong XIE

《信息与电子工程前沿（英文）》 2017年第18卷第9期页码 1261-1267 doi: 10.1631/FITEE.1601719

摘要：单像素成像技术具有利用一个单像素探测器获取高分辨图像的能力，近十年来得到广泛关注。该技术已应用于多个领域，如核磁共振成像、航天遥感、太赫兹成像和高光谱成像。与传统相机相比，单像素相机可以实现图像压缩和超宽的频谱工作范围。然而，单像素相机的成像速度受到数字微镜阵列和图像压缩程度限制，导致其时间分辨率较低（毫秒量级）。因此，观察显微成像中的高速动态现象对于单像素相机而言是巨大挑战。最近，基于光子时间拉伸的高速单像素成像技术被提出，其远超普通相机的成像速度也得到验证。本文介绍了光子时间拉伸技术的原理和应用，给出了高速单像素相机的结构，并通过实验证实利用该相机可实现高速和高吞吐量细胞流式分析，最后，讨论了高速单像素相机的局限和应用潜力。

关键词：压缩采样；单像素成像；光子时间拉伸；成像式流式细胞仪

HTML PDF 收藏

Crystallographic orientation effect on cutting-based single atomic layer removal

Wenkun XIE, Fengzhou FANG

《机械工程前沿（英文）》 2020年第15卷第4期页码 631-644 doi: 10.1007/s11465-020-0599-x

摘要： The ever-increasing requirements for the scalable manufacturing of atomic-scale devices emphasize the significance of developing atomic-scale manufacturing technology. The mechanism of a single atomic layer removal in cutting is the key basic theoretical foundation for atomic-scale mechanical cutting. Material anisotropy is among the key decisive factors that could not be neglected in cutting at such a scale. In the present study, the crystallographic orientation effect on the cutting-based single atomic layer removal of monocrystalline copper is investigated by molecular dynamics simulation. When undeformed chip thickness is in the atomic scale, two kinds of single atomic layer removal mechanisms exist in cutting-based single atomic layer removal, namely, dislocation motion and extrusion, due to the differing atomic structures on different crystallographic planes. On close-packed crystallographic plane, the material removal is dominated by the shear stress-driven dislocation motion, whereas on non-close packed crystallographic planes, extrusion-dominated material removal dominates. To obtain an atomic, defect-free processed surface, the cutting needs to be conducted on the close-packed crystallographic planes of monocrystalline copper.

关键词： ACSM single atomic layer removal mechanism crystallographic orientation effect mechanical cutting Manufacturing III

HTML PDF 收藏

Design and analysis of partially decoupled translational parallel mechanisms with single-loop structures

《机械工程前沿（英文）》 2022年第17卷第3期 doi: 10.1007/s11465-022-0695-1

摘要： This study presents a family of novel translational parallel mechanisms (TPMs) with single-loop topological structures. The proposed mechanism consists of only revolute and prismatic joints. The novel TPMs are simpler in structure and have fewer joints and components than the well-known Delta Robot. Four types of 2-degree of freedom driving systems are applied to different limb structures to avoid the moving actuator that causes the problem of increased moving mass. Four sample TPMs are constructed using the synthesized limbs, and one of them is investigated in terms of kinematic performance. First, a position analysis is performed and validated through numerical simulation to reveal the characteristics of partially decoupled motion, which improves the controllability of TPM. Second, singular configurations are identified, and the resulting singularity curve is obtained. Lastly, the workspace of TPM is analyzed, and the relationship between the singular configurations and the reachable workspace is explored. The workspace of the 3-CRR (C denotes the cylindrical joint and R denotes the revolute joint) translational mechanism is also presented to prove that the proposed TPM has a fairly large workspace.

关键词： translational parallel mechanism single loop multiple driving system workspace analysis singularity

HTML PDF 收藏

Moving policy and regulation forward for single-use plastic alternatives

《环境科学与工程前沿（英文）》 2021年第15卷第3期 doi: 10.1007/s11783-021-1423-5

摘要： Single-use plastics are often used once or cannot be reused for extended periods. They are widely consumed with the rapid development of social economy. The waste generated by single-use plastics threatens ecosystem health by entering the environment and ultimately restricts sustainable human development. The innovation of sustainable and environmentally friendly single-use plastic alternative materials and the joint participation of governments, enterprises and the public are promising technologies and management approaches that can solve the problem of single-use plastics wastes. The development of single-use plastic alternative products can be promoted fundamentally only by improving relevant legislation and standards, providing differentiated industrial policies, encouraging scientific and technological innovation and expanding public participation.

关键词： Single-use plastic alternatives Policy Regulation Sustainable development

HTML PDF 收藏

Numerical study of internal flow field and flow passage improvement of an inlet particle separator

Florian PAOLI, Tong WANG

《能源前沿（英文）》 2011年第5卷第4期页码 386-397 doi: 10.1007/s11708-011-0156-8

摘要： By performing gas flow field numerical simulations for several inlet Reynolds numbers (from 2 × 10 to 9 × 10 ) and byflow ratios (from 10% to 20%), the present study has proposed to improve the flow passage of an inlet particle separator. An adjacent objective of the study is to lower pressure losses of the inlet particle separator (IPS). No particle has been included in the gas flow for a -epsilon turbulence model. The velocity distribution in different sections and the pressure coefficient along the duct have been analyzed, which indicates that there exist important low-velocity regions and vortices in the separation area. Therefore, the profile of streamlines along the original passage has been considered. This profile illustrated a vacuum region in the same area. All investigations suggest that the separation area is the most critical one for fulfilling the objective on pressure losses limitation. Then the flow passage improvement method has focused on the separation area. An improved shape has been designed in order to suit smoothly to the streamlines in this region. Similar numerical studies as those for the original shape have been conducted on this improved shape, confirming some considerable enhancements compared with the original shape. The significant vortices which appear in the original shape reduce in amount and size. Besides, pressure losses are greatly decreased in both outlets (up to 30% for high Reynolds number) and the flow is uniform at the main outlet. Subsequent engineering surveys could rely on expressions obtained for in both outlets which extend the pressure losses for a wide range of inlet Reynolds numbers. As a result, the numerical calculations demonstrate that the flow passage improvement method applied in this study has succeeded in designing a shape which enhances the flow behavior.

关键词： streamlines pressure losses flow passage improvement inlet particle separator (IPS)

HTML PDF 收藏

Damage propagation and strength prediction of a single-lap interference-fit laminate structure

Peng ZOU, Xiangming CHEN, Hao CHEN, Guanhua XU

《机械工程前沿（英文）》 2020年第15卷第4期页码 558-570 doi: 10.1007/s11465-020-0591-5

摘要： Experimental and finite element research was conducted on the bolted interference fit of a single-lap laminated structure to reveal the damage propagation mechanism and strength change law. A typical single-lap statically loading experiment was performed, and a finite element damage prediction model was built based on intralaminar progress damage theory. The model was programmed with a user subroutine and an interlaminar cohesive zone method. The deformation and damage propagation of the specimen were analyzed, and the failure mechanism of intralaminar and interlaminar damage during loading was discussed. The effect of secondary bending moment on load translation and damage distribution was revealed. The experimental and simulated load–displacement curves were compared to validate the developed model’s reliability, and the ultimate bearing strengths under different fit percentages were predicted. An optimal percentage was also recommended.

关键词： single-lap interference fit secondary bending moment damage mechanism bearing strength

HTML PDF 收藏

Novel casting processes for single-crystal turbine blades of superalloys

Dexin MA

《机械工程前沿（英文）》 2018年第13卷第1期页码 3-16 doi: 10.1007/s11465-018-0475-0

摘要：

This paper presents a brief review of the current casting techniques for single-crystal (SC) blades, as well as an analysis of the solidification process in complex turbine blades. A series of novel casting methods based on the Bridgman process were presented to illustrate the development in the production of SC blades from superalloys. The grain continuator and the heat conductor techniques were developed to remove geometry-related grain defects. In these techniques, the heat barrier that hinders lateral SC growth from the blade airfoil into the extremities of the platform is minimized. The parallel heating and cooling system was developed to achieve symmetric thermal conditions for SC solidification in blade clusters, thus considerably decreasing the negative shadow effect and its related defects in the current Bridgman process. The dipping and heaving technique, in which thin-shell molds are utilized, was developed to enable the establishment of a high temperature gradient for SC growth and the freckle-free solidification of superalloy castings. Moreover, by applying the targeted cooling and heating technique, a novel concept for the three-dimensional and precise control of SC growth, a proper thermal arrangement may be dynamically established for the microscopic control of SC growth in the critical areas of large industrial gas turbine blades.

关键词： superalloy investment casting Bridgman process directional solidification single crystal turbine blade