资源类型

期刊论文 48

年份

2023 1

2022 5

2021 5

2020 1

2019 1

2018 4

2017 4

2016 5

2015 3

2014 1

2013 7

2012 1

2010 1

2009 1

2008 1

2007 1

2006 3

2005 1

2004 1

展开 ︾

关键词

PEDOT:PSS 1

V形坑 1

三峡工程 1

低角估计；甚高频雷达；复杂场景；多径效应；高度估计 1

体积应变 1

剪切带 1

剪切应变 1

动态输出反馈 1

单站；结构总体最小二乘；逆迭代；到达角（AOA）；到达时间（TOA）；到达频率（FOA）；多源 1

参考线 1

反Douglas算法 1

可切换移相器 1

可重构超表面 1

后处理 1

圆形巷道 1

均匀照度分布 1

塔带机 1

复杂地形 1

太赫兹通信；反射系数建模；入射角；建筑材料；菲涅耳模型 1

展开 ︾

检索范围：

排序： 展示方式：

Effect of placement angles on wireless electrocoagulation for bipolar aluminum electrodes

Zhenlian Qi, Jinna Zhang, Shijie You

《环境科学与工程前沿（英文）》 2018年 第12卷 第3期 doi: 10.1007/s11783-018-1034-y

摘要： We in our previous study reported the wireless electrocoagulation (WEC) based on bipolar electrochemistry for water purification. One of the most important advantages of WEC is the omission of ohmic connection between bipolar electrode (BPE) and power supply, and thus the electrochemical reactions on BPE are driven by electric field in solution induced by driving electrodes. In this study, the impact of placement angle of bipolar aluminum electrode on WEC was investigated to provide a detailed analysis on the correlations between the bipolar electrode placement angle and bipolar electrocoagulation reactions. The results showed that the WEC cell with a horizontal BPE placed at 0° produced the maximum dissolved aluminum coagulant, accounting for 71.6 % higher than that with a vertical one placed at 90°. Moreover, the finite element simulations of current and potential distribution were carried out along the surface of BPE at different placement angles, revealing the mechanism of different BPE placement angles on aluminum dissolution rates in WEC system.

关键词： Bipolar electrochemistry     Wireless electrocoagulation     Placement angle    

HTML PDF 收藏

Pragmatic multi-stage simulated annealing for optimal placement of synchrophasor measurement units in

Pathirikkat GOPAKUMAR,M. JAYA BHARATA REDDY,Dusmata Kumar MOHANTA

《能源前沿（英文）》 2015年 第9卷 第2期   页码 148-161 doi: 10.1007/s11708-015-0344-z

摘要： Conventional power grids across the globe are reforming to smart power grids with cutting edge technologies in real time monitoring and control methods. Advanced real time monitoring is facilitated by incorporating synchrophasor measurement units such as phasor measurement units (PMUs) to the power grid monitoring system. Several physical and economic constraints limit the deployment of PMUs in smart power grids. This paper proposes a pragmatic multi-stage simulated annealing (PMSSA) methodology for finding the optimal locations in the smart power grid for installing PMUs in conjunction with existing conventional measurement units (CMUs) to achieve a complete observability of the grid. The proposed PMSSA is much faster than the conventional simulated annealing (SA) approach as it utilizes controlled uphill and downhill movements during various stages of optimization. Moreover, the method of integrating practical phasor measurement unit (PMU) placement conditions like PMU channel limits and redundant placement can be easily handled. The efficacy of the proposed methodology has been validated through simulation studies in IEEE standard bus systems and practical regional Indian power grids.

关键词： phasor measurement units (PMUs)     pragmatic PMU placement     simulated annealing (SA)     western region Indian power grid (WRIPG)    

HTML PDF 收藏

Precise semi-analytical inverse kinematic solution for 7-DOF offset manipulator with arm angle optimization

《机械工程前沿（英文）》 2021年 第16卷 第3期   页码 435-450 doi: 10.1007/s11465-021-0630-x

摘要： Seven-degree-of-freedom redundant manipulators with link offset have many advantages, including obvious geometric significance and suitability for configu-ration control. Their configuration is similar to that of the experimental module manipulator (EMM) in the Chinese Space Station Remote Manipulator System. However, finding the analytical solution of an EMM on the basis of arm angle parameterization is difficult. This study proposes a high-precision, semi-analytical inverse method for EMMs. Firstly, the analytical inverse kinematic solution is established based on joint angle parameterization. Secondly, the analytical inverse kinematic solution for a non-offset spherical–roll–spherical (SRS) redundant manipulator is derived based on arm angle parameterization. The approximate solution of the EMM is calculated in accordance with the relationship between the joint angles of the EMM and the SRS manipulator. Thirdly, the error is corrected using a numerical method through the analytical inverse solution based on joint angle parameterization. After selecting the stride and termination condition, the precise inverse solution is computed for the EMM based on arm angle parameterization. Lastly, case solutions confirm that this method has high precision, and the arm angle parameterization method is superior to the joint angle parameterization method in terms of parameter selection.

关键词： 7-DOF redundant manipulator     inverse kinematics     semi-analytical     arm angle     link offset    

HTML PDF 收藏

Evaluating the material strength from fracture angle under uniaxial loading

Jitang FAN

《结构与土木工程前沿（英文）》 2019年 第13卷 第2期   页码 288-293 doi: 10.1007/s11709-018-0480-8

摘要： The most common experimental methods of measuring material strength are the uniaxial compressive and tensile tests. Generally, shearing fracture model occurs in both the tests. Compressive strength is higher than tensile strength for a material. Shearing fracture angle is smaller than 45° under uniaxial compression and greater than 45° under uniaxial tension. In this work, a unified relation of material strength under uniaxial compression and tension is developed by correlating the shearing fracture angle in theory. This constitutive relation is quantitatively illustrated by a function for analyzing the material strength from shear fracture angle. A computational simulation is conducted to validate this theoretical function. It is full of interest to give a scientific illustration for designing the high-strength materials and engineering structures.

关键词： strength     fracture     mechanics    

HTML PDF 收藏

Optimal placement of wind turbines within a wind farm considering multi-directional wind speed using

A.S.O. OGUNJUYIGBE, T.R. AYODELE, O.D. BAMGBOJE

《能源前沿（英文）》 2021年 第15卷 第1期   页码 240-255 doi: 10.1007/s11708-018-0514-x

摘要： Most wind turbines within wind farms are set up to face a pre-determined wind direction. However, wind directions are intermittent in nature, leading to less electricity production capacity. This paper proposes an algorithm to solve the wind farm layout optimization problem considering multi-angular (MA) wind direction with the aim of maximizing the total power generated on wind farms and minimizing the cost of installation. A two-stage genetic algorithm (GA) equipped with complementary sampling and uniform crossover is used to evolve a MA layout that will yield optimal output regardless of the wind direction. In the first stage, the optimal wind turbine layouts for 8 different major wind directions were determined while the second stage allows each of the previously determined layouts to compete and inter-breed so as to evolve an optimal MA wind farm layout. The proposed MA wind farm layout is thereafter compared to other layouts whose turbines have focused site specific wind turbine orientation. The results reveal that the proposed wind farm layout improves wind power production capacity with minimum cost of installation compared to the layouts with site specific wind turbine layouts. This paper will find application at the planning stage of wind farm.

关键词： optimal placement     wind turbines     wind direction     genetic algorithm     wake effect    

HTML PDF 收藏

具有极点区域约束的广义模糊系统的输出反馈控制

高丹,曹媛媛

《中国工程科学》 2006年 第8卷 第4期   页码 63-67

摘要：

针对模糊广义系统，将动态输出反馈控制器设计问题转化为一组矩阵不等式的可行解问题，使得闭环系统不仅具有鲁棒性能，而且能把闭环系统极点配置在一个给定的圆形区域内，从而保证系统具有期望的动态性能。

关键词： 模糊广义系统     动态输出反馈     线性矩阵不等式    

HTML PDF 收藏

Prevention of laryngeal webs through endoscopic keel placement for bilateral vocal cord lesions

null

《医学前沿（英文）》 2018年 第12卷 第3期   页码 301-306 doi: 10.1007/s11684-017-0549-0

摘要：

Transoral microresection for treatment of vocal cord lesions involving the anterior commissure may result in anterior glottic webs. In this study, we retrospectively reviewed 54 patients who underwent microsurgery for bilateral lesions involving the anterior commissure and categorized them into two groups. The keel placement and control groups received endoscopic keel placement and mitomycin C, respectively. During the follow-up of at least 1 year, the laryngeal web formation rate significantly decreased in the keel placement group compared with that in the control group (18.6% versus 54.5%, <0.05). Furthermore, the voice handicap index-10 scores for patients without web formation decreased in both the keel placement and control groups ( <0.0001 and <0.001, respectively). A pseudomembrane covering the vocal cords was detected in 16.3% (7 of 43) cases after keel removal. A total of 100% (7 of 7) of these cases and 2.8% (1 of 36) of the other cases formed laryngeal webs ( <0.0001). Endoscopic keel placement could be an effective method for preventing anterior glottic webs after surgery for bilateral vocal cord diseases involving the anterior commissure. The pseudomembrane observed at the time of keel removal may imply a high risk of web formation.

关键词： glottic stenosis     glottic web     laryngeal keel     silastic sheets     anterior commissure    

HTML PDF 收藏

Computation of the protein molecular mechanism using adaptive dihedral angle increments

Mikel DIEZ, Victor PETUYA, Mónica URIZAR, Erik MACHO, Oscar ALTUZARRRA

《机械工程前沿（英文）》 2013年 第8卷 第1期   页码 104-108 doi: 10.1007/s11465-013-0360-9

摘要：

Protein motion simulation is still a troublesome problem yet to be solved, especially due to its high computational requirements. The procedure presented in this paper makes use of the proteins’ real degrees of freedom (DOFs). The procedure makes no use of any intermediate energy minimization processes that may alter the motion path or result in very high computational cost requirements. In order to reduce the computational cost, presented algorithms make use of the balls and rods approach for protein structure modelization. Also, structures are normalized in order to minimize inaccuracies introduced by experimental methods, providing a more efficient but still accurate structure for motion simulation.

关键词： kinematics     serial robot     proteins     folding     molecular mechanism    

HTML PDF 收藏

Intelligent algorithm for optimal meter placement and bus voltage estimation in ring main distribution

L. RAMESH, N. CHAKRABORTY, S. P. CHOWDHURY

《能源前沿（英文）》 2012年 第6卷 第1期   页码 47-56 doi: 10.1007/s11708-011-0159-5

摘要： The advancement in power distribution system poses a great challenge to power engineering researchers on how to best monitor and estimate the state of the distribution network. This paper is executed in two stage processes. The first stage is to identify the optimal location for installation of monitoring instrument with minimal investment cost. The second stage is to estimate the bus voltage magnitude, where real time measurement is conducted and measured through identified meter location which is more essential for decision making in distribution supervisory control and data acquisition system (DSCADA). The hybrid intelligent technique is applied to execute the above two algorithms. The algorithms are tested with institute of electrical and electronics engineers (IEEE) and Tamil Nadu electricity board (TNEB) benchmark systems. The simulated results proves that the swarm tuned artificial neural network (ANN) estimator is best suited for accurate estimation of voltage with different noise levels.

关键词： artificial intelligence     power distribution control     state estimation    

HTML PDF 收藏

Optimal placement of PMUs for the smart grid implementation in Indian power grid—A case study

Pathirikkat GOPAKUMAR, G. Surya CHANDRA, M. Jaya Bharata REDDY, Dusmata Kumar MOHANTA

《能源前沿（英文）》 2013年 第7卷 第3期   页码 358-372 doi: 10.1007/s11708-013-0257-7

摘要： Efficient utilization of energy resources is essential for a developing country like India. The concept of smart grid (SG) can provide a highly reliable power system with optimized utilization of available resources. The present Indian power grid requires revolutionary changes to meet the growing demands and to make the grid smarter and reliable. One of the important requirements for SG is the instantaneous monitoring of the voltage, current and power flows at all buses in the grid. The traditional monitoring system cannot satisfy this requirement since they are based on nonlinear power flow equations. Synchro-phasor-measurement devices like phasor measurement units (PMUs) can measure the phasor values of voltages at installed buses. Consequently, the currents passing through all branches connected to that bus can be computed. Since the voltage phasor values at the neighboring buses of a bus containing the PMU can be estimated using Ohm’s law, it is redundant to install PMUs at all the buses in a power grid for its complete observability. This paper proposes the optimal geographical locations for the PMUs in southern region Indian power grid for the implementation of SG, using Integer Linear Programming. The proposed optimal geographical locations for PMU placement can be a stepping stone for the implementation of SG in India.

关键词： phasor measurement units (PMUs)     smart grid (SG)     southern region Indian power grid (SRIPG)     integer linear programming (ILP)    

HTML PDF 收藏

CFD simulation on shell-and-tube heat exchangers with small-angle helical baffles

Minhua ZHANG,Fang MENG,Zhongfeng GENG

《化学科学与工程前沿（英文）》 2015年 第9卷 第2期   页码 183-193 doi: 10.1007/s11705-015-1510-x

摘要： Shell-and-tube heat exchanger with helical baffles is superior to that with segmental baffles in reducing pressure drop, eliminating dead zone and lowering the risks of vibration of tube bundle. This paper focused on the small-angle helical baffles that have been merely reported in open literature. These baffles are noncontinuous helical baffles with a helix angle of 10° to 30°, and their shapes are 1/4 ellipse, 1/4 sector and 1/3 sector. To assess the integrative performance, /? is employed, and the calculated results show that among the three baffle shapes the heat exchangers with a 1/4 sector helical baffle have the lowest pressure drop. At = 10° and 20°, 1/4 sector helical baffle heat exchangers show the best integrative performance; at = 30°, 1/4 ellipse and 1/4 sector helical baffle heat exchangers perform almost the same. For the study of helix angles, we found that 30° has the best integrative performance at low mass flow rate, almost the same as 20° at high mass flow rate.

关键词： heat transfer     pressure drop     helical baffle     CFD    

HTML PDF 收藏

Effects of Boundary Condition and Helix Angle on Meshing Performance of TI Worm Gearing

SUN Yue-hai, DUAN Lu-qian, WANG Shu-ren, ZHANG Ce

《机械工程前沿（英文）》 2006年 第1卷 第1期   页码 90-95 doi: 10.1007/s11465-005-0006-7

摘要：

To exactly describe the contact state and contact area of tooth surface of toroidal involute (TI) worm gearing, the authors introduced boundary condition into contact line analysis.With helix angle chosen as parameter, the criterion for the existence of meshing boundary line on the surface of TI worm gearing is derived. Results show that there can be four situations for meshing boundary line on the tooth surface of gear, namely, inexistence of meshing boundary line, a unique line, two lines, and two coincident lines. If the helix angle is equal to or slightly smaller than the bigger angle, which makes two meshing boundary lines superpose, a preferable meshing performance is obtained. Computer simulation proves the validity of the above conclusion.

关键词： preferable     inexistence     Results     validity     boundary condition    

HTML PDF 收藏

Comparison of optimal capacitor placement methods in radial distribution system with load growth and

Veera Venkata Satya Naryana MURTY, Ashwani KUMAR

《能源前沿（英文）》 2013年 第7卷 第2期   页码 197-213 doi: 10.1007/s11708-013-0249-7

摘要： In this paper, a combined power loss sensitivity (PLS) index-based approach is proposed to determine the optimal location of the capacitors in the radial distribution system (RDS) based on the real and reactive combined loss sensitivity index, as capacitor placement not only reduces real power loss with voltage profile improvement but also reduces reactive power loss due to the reactive power compensation in the network. The results have been obtained with the existing methods of power loss index (PLI) and index vector (IV) method for comparison. Besides, the optimal placement has been obtained with the proposed method as well as existing methods and the total kVar support has been obtained. In addition, the results of net cost savings for the 10-, 34-, and 69-bus systems are obtained for comparison. Moreover, the results have been obtained for a large system of 85 buses to validate the results with combined sensitivity based approach. Furthermore, the load growth factor has been considered in the study which is essential for the planning and expansion of the existing systems, whereas the impact of the realistic load model as ZIP load model has been considered for the study of all the systems.

关键词： load growth     load models     reactive power compensation     radial distribution system     power loss index (PLI)     power loss sensitivity (PLS)     index vector (IV)    

HTML PDF 收藏

Industrial-scale investigations on effects of tertiary-air declination angle on combustion and steam

Xiaoguang LI, Lingyan ZENG, Hongye LIU, Yao LI, Yifu LI, Yunlong ZHAO, Bo JIAO, Minhang SONG, Shaofeng ZHANG, Zhichao CHEN, Zhengqi LI

《能源前沿（英文）》 2021年 第15卷 第1期   页码 132-142 doi: 10.1007/s11708-020-0803-z

摘要： Industrial-scale experiments were conducted to study the effects of tertiary air declination angle (TDA) on the coal combustion and steam temperature characteristics in the first 350-MW supercritical down-fired boiler in China with the multiple-injection and multiple-staging combustion (MIMSC) technology at medium and high loads. The experimental results indicated that as the TDA increased from 0° to 15°, the overall gas temperature in the lower furnace rose and the symmetry of temperature field was enhanced. The ignition distance of the fuel-rich coal/air flow decreased. In near-burner region, the concentration of O decreased while the concentrations of CO and NO increased. The concentration of NO decreased in near-tertiary-air region. The carbon in fly ash decreased significantly from 8.40% to 6.45% at a load of 260 MW. At a TDA of 15°, the ignition distances were the shortest (2.07 m and 1.73 m) at a load of 210 MW and 260 MW, respectively. The main and reheat steam temperatures were the highest (557.2°C and 559.4°C at a load of 210 MW, 558.4°C and 560.3°C at a load of 260 MW). The carbon in fly ash was the lowest (4.83%) at a load of 210 MW. On changing the TDA from 15° to 25°, the flame kernel was found to move downward and the main and reheat steam temperatures dropped obviously. The change of TDA has little effect on NO emissions(660–681 mg/m at 6% O ). In comprehensive consideration of the pulverized coal combustion characteristics and the unit economic performance, an optimal TDA of 15° is recommended.

关键词： supercritical down-fired boiler     industrial-scale experiment     tertiary air declination angle     coal combustion     steam temperature    

HTML PDF 收藏

A Miniature Meta-Optical System for Reconfigurable Wide-Angle Imaging and Polarization-Spectral Detection

Fei Zhang,Minghao Liao,Mingbo Pu,Yinghui Guo,Lianwei Chen,Xiong Li,Qiong He,Tongtong Kang,Xiaoliang Ma,Yuan Ke,Xiangang Luo,

《工程（英文）》 doi: 10.1016/j.eng.2023.07.008

摘要： Wide-angle imaging and spectral detection play vital roles in tasks such as target tracking, object classification, and anti-camouflage. However, limited by their intrinsically different architectures, as determined by frequency dispersion requirements, their simultaneous implementation in a shared-aperture system is difficult. Here, we propose a novel concept to realize reconfigurable dual-mode detection based on electrical-control tunable metasurfaces. As a proof-of-concept demonstration, the simultaneous implementation of wide-angle imaging and polarization-spectral detection in a miniature shared-aperture meta-optical system is realized for the first time via the electrical control of cascaded catenary-like metasurfaces. The proposed system supports the imaging (spectral) resolution of approximately 27.8 line-pairs per millimeter (lp·mm−1; ∼80 nm) for an imaging (spectral) mode from 8 to 14 μm. This system also bears a large field of view of about 70°, enabling multi-target recognition in both modes. This work may promote the miniaturization of multifunctional optical systems, including spectrometers and polarization imagers, and illustrates the potential industrial applications of meta-optics in biomedicine, security, space exploration, and more.

关键词： Metasurfaces     Reconfigurable     Imaging     Spectral    

HTML PDF 收藏

标题 作者 时间 类型 操作

Effect of placement angles on wireless electrocoagulation for bipolar aluminum electrodes

Zhenlian Qi, Jinna Zhang, Shijie You

期刊论文

Pragmatic multi-stage simulated annealing for optimal placement of synchrophasor measurement units in

Pathirikkat GOPAKUMAR,M. JAYA BHARATA REDDY,Dusmata Kumar MOHANTA

期刊论文

Precise semi-analytical inverse kinematic solution for 7-DOF offset manipulator with arm angle optimization

期刊论文

Evaluating the material strength from fracture angle under uniaxial loading

Jitang FAN

期刊论文

Optimal placement of wind turbines within a wind farm considering multi-directional wind speed using

A.S.O. OGUNJUYIGBE, T.R. AYODELE, O.D. BAMGBOJE

期刊论文

具有极点区域约束的广义模糊系统的输出反馈控制

高丹,曹媛媛

期刊论文

Prevention of laryngeal webs through endoscopic keel placement for bilateral vocal cord lesions

null

期刊论文

Computation of the protein molecular mechanism using adaptive dihedral angle increments

Mikel DIEZ, Victor PETUYA, Mónica URIZAR, Erik MACHO, Oscar ALTUZARRRA

期刊论文

Intelligent algorithm for optimal meter placement and bus voltage estimation in ring main distribution

L. RAMESH, N. CHAKRABORTY, S. P. CHOWDHURY

期刊论文

Optimal placement of PMUs for the smart grid implementation in Indian power grid—A case study

Pathirikkat GOPAKUMAR, G. Surya CHANDRA, M. Jaya Bharata REDDY, Dusmata Kumar MOHANTA

期刊论文

CFD simulation on shell-and-tube heat exchangers with small-angle helical baffles

Minhua ZHANG,Fang MENG,Zhongfeng GENG

期刊论文

Effects of Boundary Condition and Helix Angle on Meshing Performance of TI Worm Gearing

SUN Yue-hai, DUAN Lu-qian, WANG Shu-ren, ZHANG Ce

期刊论文

Comparison of optimal capacitor placement methods in radial distribution system with load growth and

Veera Venkata Satya Naryana MURTY, Ashwani KUMAR

期刊论文

Industrial-scale investigations on effects of tertiary-air declination angle on combustion and steam

Xiaoguang LI, Lingyan ZENG, Hongye LIU, Yao LI, Yifu LI, Yunlong ZHAO, Bo JIAO, Minhang SONG, Shaofeng ZHANG, Zhichao CHEN, Zhengqi LI

期刊论文

A Miniature Meta-Optical System for Reconfigurable Wide-Angle Imaging and Polarization-Spectral Detection

Fei Zhang,Minghao Liao,Mingbo Pu,Yinghui Guo,Lianwei Chen,Xiong Li,Qiong He,Tongtong Kang,Xiaoliang Ma,Yuan Ke,Xiangang Luo,

期刊论文