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 322

年份

2024 1

2023 28

2022 22

2021 15

2020 23

2019 17

2018 25

2017 32

2016 8

2015 12

2014 11

2013 17

2012 2

2011 9

2010 12

2009 15

2008 16

2007 20

2006 6

2005 3

展开︾

关键词

三峡工程 2

增材制造 2

微反应器 2

显微硬度 2

立堵截流 2

膨化硝酸铵 2

高端计算 2

3D打印 1

5G 1

AD9954 1

AQAM 1

ATP荧光检测 1

BOT 1

HMAC-SM3；侧信道分析；相关能量攻击；基于比特值的选择明文 1

Hilbert变换 1

LED战略性中心企业 1

LED高端制造装备 1

OFDM 1

PPP模式 1

展开︾

检索范围：

排序：展示方式：

Effect of Joule heating on electro-osmotic flow in a closed-end micro-channel with isothermal and convective

Liang ZHAO, Linhua LIU,

《能源前沿（英文）》 2009年第3卷第4期页码 381-388 doi: 10.1007/s11708-009-0057-2

摘要： The effect of Joule heating on the steady state electro-osmotic flow in a closed-end micro-channel is studied through numerical simulation with the finite volume method. The velocity field and the temperature field are described by a rigorous mathematical model. Thermophysical properties including viscosity and thermal conductivity are considered to be temperature-dependent. The simulations show that the presence of Joule heating causes an increase in temperature and a decrease in viscosity in the whole micro-channel, which, thereafter, induce a large velocity near the wall and an increase in fluid velocity at the central region in order to maintain a zero flow rate at the cross section of the micro-channel. The effect of Joule heating on the induced pressure gradient is also studied, which is very important for the application of the closed-end micro-channel as a micro-actuator. The results reveal that the induced pressure gradient, taking into consideration Joule heating, is significantly smaller than that without considering Joule heating when the wall temperature of the micro-channel is constant. The induced pressure gradient difference between considering Joule heating and without considering Joule heating is small under the convective boundary condition.

关键词： closed-end micro-channel electrical double layer electro-osmotic flow induced pressure gradient Joule heating

HTML PDF 收藏

Numerical simulation of micro scale flowing and boiling

Wen WANG, Rui ZHUAN,

《能源前沿（英文）》 2009年第3卷第4期页码 396-401 doi: 10.1007/s11708-009-0049-2

摘要： Numerical simulations of flowing and boiling in micro channels are presented, including the modeling of bubble dynamics of nucleate boiling, and a description of the interface of two phases with the volume-of-fluid (VOF). The two calculated cases are compared with related experimental data in literature. Some simulated results are found corresponding well to the experimental data. The simulated results also show the details of 3-dimensional heat transfer and the flow in micro channels, which are helpful to the investigation of the mechanism of two-phase heat transfer and flow in micro channels.

关键词： volume-of-fluid (VOF) micro channel nucleate boiling bubble dynamics simulation

HTML PDF 收藏

3D finite element prediction of chip flow, burr formation, and cutting forces in micro end-milling of

A. DAVOUDINEJAD, P. PARENTI, M. ANNONI

《机械工程前沿（英文）》 2017年第12卷第2期页码 203-214 doi: 10.1007/s11465-017-0421-6

摘要：

Predictive models for machining operations have been significantly improved through numerous methods in recent decades. This study proposed a 3D finite element modeling (3D FEM) approach for the micro end-milling of Al6061-T6. Finite element (FE) simulations were performed under different cutting conditions to obtain realistic numerical predictions of chip flow, burr formation, and cutting forces. FE modeling displayed notable advantages, such as capability to easily handle any type of tool geometry and any side effect on chip formation, including thermal aspect and material property changes. The proposed 3D FE model considers the effects of mill helix angle and cutting edge radius on the chip. The prediction capability of the FE model was validated by comparing numerical model and experimental test results. Burr dimension trends were correlated with force profile shapes. However, the FE predictions overestimated the real force magnitude. This overestimation indicates that the model requires further development.

关键词： 3D finite element modeling micro end-milling cutting force chip formation burr formation

HTML PDF 收藏

Topology-independent end-to-end learning model for improving the voltage profile in microgrids-integrated

《能源前沿（英文）》 2023年第17卷第2期页码 211-227 doi: 10.1007/s11708-022-0847-3

摘要： With multiple microgrids (MGs) integrated into power distribution networks in a distributed manner, the penetration of renewable energy like photovoltaic (PV) power generation surges. However, the operation of power distribution networks is challenged by the issues of multiple power flow directions and voltage security. Accordingly, an efficient voltage control strategy is needed to ensure voltage security against ever-changing operating conditions, especially when the network topology information is absent or inaccurate. In this paper, we propose a novel data-driven voltage profile improvement model, denoted as system-wide composite adaptive network (SCAN), which depends on operational data instead of network topology details in the context of power distribution networks integrated with multiple MGs. Unlike existing studies that realize topology identification and decision-making optimization in sequence, the proposed end-to-end model determines the optimal voltage control decisions in one shot. More specifically, the proposed model consists of four modules, Pre-training Network and modified interior point methods with adversarial networks (Modified IPMAN) as core modules, and discriminator generative adversarial network (Dis-GAN) and Volt convolutional neural network (Volt-CNN) as ancillary modules. In particular, the generator in SCAN is trained by the core modules in sequence so as to form an end-to-end mode from data to decision. Numerical experiments based on IEEE 33-bus and 123-bus systems have validated the effectiveness and efficiency of the proposed method.

关键词： end-to-end learning microgrids voltage profile improvement generative adversarial network

HTML PDF 收藏

Experimental investigations on operating characteristics of a closed loop pulsating heat pipe

Yu WANG

《能源前沿（英文）》 2015年第9卷第2期页码 134-141 doi: 10.1007/s11708-015-0354-x

摘要： The operating mechanism of the pulsating heat pipe (PHP) is not well understood and the present technology cannot predict required design parameters for a given task. The aim of research work presented in this paper is to better understand the operation regimes of the PHP through experimental investigations. A series of experiments were conducted on a closed loop PHP with 5 turns made of copper capillary tube of 2 mm in inner diameter. Two different working fluids viz. ethanol and acetone were employed. The operating characteristics were studied for the variation of heat input, filling ratio (FR) and inclination angle of the tested device. The results strongly demonstrate the effect of the filling ratio of the working fluid on the operational stability and heat transfer capability of the device. Important insight into the operational characteristics of PHP has been obtained.

关键词： closed loop pulsating heat pipe thermal performance operation limit thermography

HTML PDF 收藏

Improvement of the cascading closed loop cycle system

ZHANG Guoqiang, CAI Ruixian

《能源前沿（英文）》 2007年第1卷第3期页码 341-346 doi: 10.1007/s11708-007-0051-5

摘要： Aspen Plus was used to simulate and get more information about the cascading closed loop cycle (CCLC) system [1–3]. Following evaluation of the variable temperature heat source (e.g. gas turbine flue gas) utilized by the CCLC, both qualitative and quantitive comparisons between the system and simple steam Rankine cycle, were made. The results indicate that CCLC has the advantage in recuperating exergy from flue gas, but it cannot sufficiently convert the recuperated exergy to useful work. To improve the utilization of low temperature flue gas heat, the properties and parameters of the working substance must match conditions of the low temperature heat source. A better cycle scheme and pressure distribution was proposed to raise the efficiency of the CCLC. In addition, the multifunction system concept was introduced to improve the performance of CCLC with solar energy.

HTML PDF 收藏

Dynamic simulation of a space gas-cooled reactor power system with a closed Brayton cycle

《能源前沿（英文）》 2021年第15卷第4期页码 916-929 doi: 10.1007/s11708-021-0757-9

摘要： Space nuclear reactor power (SNRP) using a gas-cooled reactor (GCR) and a closed Brayton cycle (CBC) is the ideal choice for future high-power space missions. To investigate the safety characteristics and develop the control strategies for gas-cooled SNRP, transient models for GCR, energy conversion unit, pipes, heat exchangers, pump and heat pipe radiator are established and a system analysis code is developed in this paper. Then, analyses of several operation conditions are performed using this code. In full-power steady-state operation, the core hot spot of 1293 K occurs near the upper part of the core. If 0.4 $ reactivity is introduced into the core, the maximum temperature that the fuel can reach is 2059 K, which is 914 K lower than the fuel melting point. The system finally has the ability to achieve a new steady-state with a higher reactor power. When the GCR is shut down in an emergency, the residual heat of the reactor can be removed through the conduction of the core and radiation heat transfer. The results indicate that the designed GCR is inherently safe owing to its negative reactivity feedback and passive decay heat removal. This paper may provide valuable references for safety design and analysis of the gas-cooled SNRP coupled with CBC.

关键词： gas-cooled space nuclear reactor power closed Brayton cycle system startup and shutdown positive reactivity insertion accident

HTML PDF 收藏

28 GHz城市微蜂窝场景中上行与下行信道空间特性

姜涛,张建华,唐盼,田磊

《信息与电子工程前沿（英文）》 2021年第22卷第4期页码 488-502 doi: 10.1631/FITEE.2000443

摘要：介绍了28 GHz城市微蜂窝（UMi）场景中上行和下行链路的水平到达角（AoA）实验研究。目前，大多数毫米波频段的角度测量都在下行链路中进行，然后利用信道互易性来推断上行链路情况。尽管上行链路和下行链路的信道相关系数可以高达0.8，但这并不意味着它们完全相同。只有对真实的上行链路进行测量才能准确描述其信道状况，这也是本文的研究目的。在模拟上行链路和下行链路时，将配备有可旋转喇叭天线的接收机分别置于基站和用户终端。为提高角度分辨率，使用空间替代广义期望最大化（SAGE）算法提取多径分量（MPC），然后使用空间波瓣方法对MPC在功率角谱中分簇。通过将MPC与环境中的对象匹配，发现直射传播和一阶反射传播分别在视距（LoS）和非视距（NLoS）情况下占主导地位。通过将测量结果与标准信道模型比较，可以验证AoA的簇心角在上行链路和下行链路中均遵循高斯分布。最后，为簇内多径的AoA和功率建立二维高斯模型，以反映它们的相关性。

关键词：信道测量；毫米波；上行链路；下行链路；水平到达角

HTML PDF 收藏

低高宽比矩形微通道中流动沸腾的压降特性

张炳雷,徐进良,肖泽军

《中国工程科学》 2007年第9卷第12期页码 86-93

摘要：以甲醇为工质，在不同进口温度、质量流率、热流密度和倾角下，对低高宽比矩形微通道中流动沸腾压降特性进行了研究，并分别采用均相模型和分相模型对通道压降进行了计算。通过对比实验结果与计算结果发现，均相模型中两相平均粘度的计算应当采用Dukler公式，用其他计算式时误差较大；利用LockhartMartinelli关系式进行的分相模型计算发现，现有C值计算公式，如Chisholm,Lee and Lee，Mishima及Qu and Mudawar等，都不能用于预测该实验中低高宽比微通道的两相压降。实验发现当通

关键词：压降特性；均相模型；分相模型；微通道；流动沸腾

HTML PDF 收藏

General closed-form inverse kinematics for arbitrary three-joint subproblems based on the product of

《机械工程前沿（英文）》 2022年第17卷第2期 doi: 10.1007/s11465-022-0681-7

摘要： The inverse kinematics problems of robots are usually decomposed into several Paden–Kahan subproblems based on the product of exponential model. However, the simple combination of subproblems cannot solve all the inverse kinematics problems, and there is no common approach to solve arbitrary three-joint subproblems in an arbitrary postural relationship. The novel algebraic geometric (NAG) methods that obtain the general closed-form inverse kinematics for all types of three-joint subproblems are presented in this paper. The geometric and algebraic constraints are used as the conditions precedent to solve the inverse kinematics of three-joint subproblems. The NAG methods can be applied in the inverse kinematics of three-joint subproblems in an arbitrary postural relationship. The inverse kinematics simulations of all three-joint subproblems are implemented, and simulation results indicating that the inverse solutions are consistent with the given joint angles validate the general closed-form inverse kinematics. Huaque III minimally invasive surgical robot is used as the experimental platform for the simulation, and a master–slave tracking experiment is conducted to verify the NAG methods. The simulation result shows the inverse solutions and six sets given joint angles are consistent. Additionally, the mean and maximum of the master–slave tracking experiment for the closed-form solution are 0.1486 and 0.4777 mm, respectively, while the mean and maximum of the master–slave tracking experiment for the compensation method are 0.3188 and 0.6394 mm, respectively. The experiments results demonstrate that the closed-form solution is superior to the compensation method. The results verify the proposed general closed-form inverse kinematics based on the NAG methods.

关键词： inverse kinematics Paden–Kahan subproblems three-joint subproblems product of exponential closed-form solution

HTML PDF 收藏

A cellphone-based colorimetric multi-channel sensor for water environmental monitoring

《环境科学与工程前沿（英文）》 2022年第16卷第12期 doi: 10.1007/s11783-022-1590-z

摘要：

● A cellphone-based colorimetric multi-channel sensor for in-field detection.

关键词： Colorimetric analysis Multi-channel sensor Cellphone Water quality indexes Environmental monitoring

HTML PDF 收藏

Analysis of nonlinear channel friction inverse problem

CHENG Weiping, LIU Guohua

《结构与土木工程前沿（英文）》 2007年第1卷第2期页码 205-210 doi: 10.1007/s11709-007-0024-0

摘要： Based on the Backus-Gilbert inverse theory, the singular value decomposition (SVD) for general inverse matrices and the optimization algorithm are used to solve the channel friction inverse problem. The resolution and covariance friction inverse model in matrix form is developed to examine the reliability of solutions. Theoretical analyses demonstrate that the convergence rate of the general Newton optimization algorithm is in the second-order. The Wiggins method is also incorporated into the algorithm. Using the method, noise can be suppressed effectively, and the results are close to accurate solutions with proper control parameters. Also, the numerical stability can be improved.

关键词： singular SVD second-order covariance Theoretical

HTML PDF 收藏

Analysis of stress and failure in rock specimens with closed and open flaws on the surface

《结构与土木工程前沿（英文）》 2021年第15卷第5期页码 1222-1237 doi: 10.1007/s11709-021-0773-1

摘要： The influence of closed and open surface flaws on the stress distribution and failure in rock specimens is investigated. Heterogeneous finite element models are developed to simulate the compression tests on flawed rock specimens. The simulated specimens include those with closed flaws and those with open flaws on the surface. Systematic analyses are conducted to investigate the influences of the flaw inclination, friction coefficient and the confining stress on failure behavior. Numerical results show significant differences in the stress, displacement, and failure behavior of the closed and open flaws when they are subjected to pure compression; however, their behaviors under shear and tensile loads are similar. According to the results, when compression is the dominant mode of stress applied to the flaw surface, an open flaw may play a destressing role in the rock and relocate the stress concentration and failure zones. The presented results in this article suggest that failure at the rock surface may be managed in a favorable manner by fabricating open flaws on the rock surface. The insights gained from this research can be helpful in managing failure at the boundaries of rock structures.

关键词： surface flaw heterogeneity circular hole numerical modeling relative displacement

HTML PDF 收藏

一种端到端语音合成中的高效解码自注意力网络 Research Article

赵伟1,2,许力1,2

《信息与电子工程前沿（英文）》 2022年第23卷第7期页码 1127-1138 doi: 10.1631/FITEE.2100501

摘要：自注意力网络由于其并行结构和强大的序列建模能力，被广泛应用于语音合成（TTS）领域。然而，当使用自回归解码方法进行端到端语音合成时，由于序列长度的二次复杂性，其推理速度相对较慢。当部署设备未配备图形处理器（GPU）时，该效率问题更加严重。为解决该问题，提出一种高效解码自注意力网络（EDSA）作为替代。通过一个动态规划解码过程，有效加速TTS模型推理，使其具有线性计算复杂度。基于普通话和英文数据集的实验结果表明，所提EDSA模型在中央处理器（CPU）和GPU上的推理速度分别提高720%和50%，而性能几乎相同。因此，在GPU资源有限的情况下，该方法可使此类模型的部署更加容易。此外，所提模型在域外语言处理上可能比基线Transformer TTS性能更好。

关键词：高效解码；端到端；自注意力网络；语音合成

HTML PDF 收藏

Comparison on End-of-Life strategies of WEEE in China based on LCA

Bin Lu, Xiaolong Song, Jianxin Yang, Dong Yang

《环境科学与工程前沿（英文）》 2017年第11卷第5期 doi: 10.1007/s11783-017-0994-7

摘要： As the Electrical and Electronic Equipment (EEE) are upgraded more frequently in China, a large quantity of Waste Electrical and Electronic Equipment (WEEE) was and will be generated. It becomes an urgent issue to develop and adopt an effective End-of-Life (EoL) strategy for EEE in order to balance the resource recovery and environmental impacts. In an EoL strategy hierarchy for EEE, reuse strategy is usually deemed to be prior to materials recovery and other strategies. But in practice, the advantages and disadvantages of different strategies are always context-dependent. Therefore, main EoL strategies for EEE in China need to be evaluated in environment and resources aspects from the life cycle perspective. In this study, the obsolete refrigerator and Power Supply Unit (PSU) of desktop PC are both taken as the target products. Life Cycle Assessment (LCA) is applied to assess the environmental impacts of different EoL scenarios in China: Unit Reuse Scenario (URS), Component Reuse Scenario (CRS) and Materials Recovery Scenario (MRS). The LCA results show that the EoL strategies hierarchy is reasonable for the part of computer, but not necessarily suitable for obsolete refrigerators. When the policy makers promote or demote one EoL strategy especially reuse, it is necessary to take subsequent impacts into consideration.

关键词： End-of-Life Waste electrical and electronic equipment Life cycle assessment Reuse