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 1558

年份

2024 2

2023 117

2022 132

2021 124

2020 136

2019 99

2018 89

2017 84

2016 85

2015 98

2014 81

2013 59

2012 62

2011 40

2010 52

2009 48

2008 41

2007 41

2006 28

2005 29

展开︾

关键词

数学模型 13

模型试验 9

数值模拟 8

模型 7

COVID-19 6

深度学习 4

GM(1 3

不确定性 3

医院中子照射器I型堆 3

计算机模拟 3

1)模型 2

DX桩 2

D区 2

Preissmann格式 2

Weibull分布 2

k-ε模型 2

临震信号 2

云模型 2

人员疏散 2

展开︾

检索范围：

排序：展示方式：

Analysis of flow over backward facing step with transition

Dwarikanath RATHA,Arindam SARKAR

《结构与土木工程前沿（英文）》 2015年第9卷第1期页码 71-81 doi: 10.1007/s11709-014-0270-x

摘要： The present study deals with the study of the velocity distribution and the separation phenomenon of flow of air over a two dimensional backward facing step. The flow of air over a backward facing step has been investigated numerically using FLUENT. Flow simulation has been carried out in a backward facing step having an expansion ratio (ratio of the height before and after the step) of 1:1.94 and the results obtained are compared with the published experimental results. Comparison of flow characteristics between steps with three different transitions is made. The variation of reattachment length for all the three cases are analyzed for wide range of Reynolds number ranging from 100 to 7000 which covers the laminar, transition and turbulent flow of air. Simulation of the flow over steps with expansion ratios of 1:1.24, 1:1.38, 1:1.47, 1:1.53, 1:1.94, 1:2.20 are also carried out to examine the effect of different expansion ratios on the reattachment length. It is found that the primary reattachment length increases with increase in the expansion ratio. The primary reattachment length at the bottom wall downstream of the step is minimum for the step with round edged transition and maximum for the step with a vertical drop transition.

关键词： Reattachment length backward facing step transition flow separation k-? model

HTML PDF 收藏

Multi-color space threshold segmentation and self-learning ki>-NN algorithm for surge test EUT status

Jian HUANG,Gui-xiong LIU

《机械工程前沿（英文）》 2016年第11卷第3期页码 311-315 doi: 10.1007/s11465-016-0376-z

摘要：

The identification of targets varies in different surge tests. A multi-color space threshold segmentation and self-learning k-nearest neighbor algorithm (k-NN) for equipment under test status identification was proposed after using feature matching to identify equipment status had to train new patterns every time before testing. First, color space (L*a*b*, hue saturation lightness (HSL), hue saturation value (HSV)) to segment was selected according to the high luminance points ratio and white luminance points ratio of the image. Second, the unknown class sample S_r was classified by the k-NN algorithm with training set T_z according to the feature vector, which was formed from number of pixels, eccentricity ratio, compactness ratio, and Euler’s numbers. Last, while the classification confidence coefficient equaled k, made S_r as one sample of pre-training set T_z′. The training set T_z increased to T_z₊₁ by T_z′ if T_z′ was saturated. In nine series of illuminant, indicator light, screen, and disturbances samples (a total of 21600 frames), the algorithm had a 98.65% identification accuracy, also selected five groups of samples to enlarge the training set from T₀ to T₅ by itself.

关键词： multi-color space k-nearest neighbor algorithm (k-NN) self-learning surge test

HTML PDF 收藏

A systematic approach in load disaggregation utilizing a multi-stage classification algorithm for consumer electrical appliances classification

Chuan Choong YANG, Chit Siang SOH, Vooi Voon YAP

《能源前沿（英文）》 2019年第13卷第2期页码 386-398 doi: 10.1007/s11708-017-0497-z

摘要： The potential to save energy in existing consumer electrical appliances is very high. One of the ways to achieve energy saving and improve energy use awareness is to recognize the energy consumption of individual electrical appliances. To recognize the energy consumption of consumer electrical appliances, the load disaggregation methodology is utilized. Non-intrusive appliance load monitoring (NIALM) is a load disaggregation methodology that disaggregates the sum of power consumption in a single point into the power consumption of individual electrical appliances. In this study, load disaggregation is performed through voltage and current waveform, known as the - trajectory. The classification algorithm performs cropping and image pyramid reduction of the - trajectory plot template images before utilizing the principal component analysis (PCA) and the -nearest neighbor ( -NN) algorithm. The novelty of this paper is to establish a systematic approach of load disaggregation through - trajectory-based load signature images by utilizing a multi-stage classification algorithm methodology. The contribution of this paper is in utilizing the “ -value,” the number of closest data points to the nearest neighbor, in the -NN algorithm to be effective in classification of electrical appliances. The results of the multi-stage classification algorithm implementation have been discussed and the idea on future work has also been proposed.

关键词： load disaggregation voltage-current (V-I) trajectory multi-stage classification algorithm principal component analysis (PCA) k-nearest neighbor (k-NN)

HTML PDF 收藏

Elasto-plastic fatigue crack growth analysis of plane problems in the presence of flaws using XFEM

SHEDBALE,I. V. SINGH,B. K. MISHRA

《结构与土木工程前沿（英文）》 2015年第9卷第4期页码 420-440 doi: 10.1007/s11709-015-0305-y

摘要： In this paper, elasto-plastic XFEM simulations have been performed to evaluate the fatigue life of plane crack problems in the presence of various defects. The stress-strain response of the material is modeled by Ramberg-Osgood equation. The von-Mises failure criterion has been used with isotropic hardening. The -integral for two fracture modes (mode-I and mode-II) is obtained by decomposing the displacement and stress fields into their symmetric and antisymmetric parts, then individual stress intensity factors are extracted from -integral. The fatigue life obtained by EPFM is found quite close to that obtained by LEFM.

关键词： XFEM von-Mises yield criterion isotropic hardening fatigue crack growth J-integral

HTML PDF 收藏

Investigation on the freeze-thaw damage to the jointed plain concrete pavement under different climate conditions

Shuaicheng GUO, Qingli DAI, Jacob HILLER

《结构与土木工程前沿（英文）》 2018年第12卷第2期页码 227-238 doi: 10.1007/s11709-017-0426-6

摘要： Freeze-thaw damage is one of the main threats to the long time performance of the concrete pavement in the cold regions. This project aims to evaluate the influence of the freeze-thaw damages on pavement distresses under different climate conditions. Based on the Long-Term Pavement Performance (LTPP) data base, the freeze-thaw damage generated by four different kinds of climate conditions are considered in this project: wet-freeze, wet-non freeze, dry-freeze and dry-non freeze. The amount of the transverse crack and the joint spalling, along with the International Roughness Index ( ) are compared among the test sections located in these four different climate conditions. The back calculation with the Falling Weight Deflectometer (FWD) test results based on the ERES and the Estimation of Concrete Pavement Parameters (ECOPP) methods are conducted to obtain concrete slab elastic modulus and the subgrade -value. These two parameters both decrease with service time under freeze condition. Finally, MEPDG simulation is conducted to simulate the development with service year. These results showed the reasonable freeze-thaw damage development with pavement service life and under different climate conditions.

关键词： LTPP elastic modulus k-value IRI MEPDG

HTML PDF 收藏

K⁺ and Na⁺ fluxes in roots of two Chinese Iris populations

Pinfang LI,Biao ZHANG

《农业科学与工程前沿（英文）》 2014年第1卷第2期页码 144-149 doi: 10.15302/J-FASE-2014016

摘要： Maintenance of ion homeostasis, particularly the regulation of K and Na uptake, is important for all plants to adapt to salinity. Observations on ionic response to salinity and net fluxes of K , Na in the root exhibited by plants during salt stress have highlighted the need for further investigation. The objectives of this study were to compare salt adaptation of two Chinese Iris ( Pall. var. (Fisch.) Koidz.) populations, and to improve understanding of adaptation to salinity exhibited by plants. Plants used in this study were grown from seeds collected in the Xinjiang Uygur Autonomous Region (Xj) and Beijing Municipality (Bj), China. Hydroponically-grown seedlings of the two populations were supplied with nutrient solutions containing 0.1 (control) and 140 mmol·L NaCl. After 12 days, plants were harvested for determination of relative growth rate and K , Na concentrations. Net fluxes of K , Na from the apex and along the root axis to 10.8 mm were measured using non-invasive micro-test technique. With 140 mmol·L NaCl treatment, shoots for population Xj had larger relative growth rate and higher K concentration than shoots for population Bj. However, the Na concentrations in both shoots and roots were lower for Xj than those for Bj. There was a lower net efflux of K found in population Xj than by Bj in the mature zone (approximately 2.4-10.8 mm from root tip). However, no difference in the efflux of Na between the populations was obtained. Population Xj of continued to grow normally under NaCl stress, and maintained a higher K /Na ratio in the shoots. These traits, which were associated with lower K leakage, help population Xj adapt to saline environments.

关键词： Iris lactea Pall. var. chinensis (Fisch.) Koidz population K⁺ and Na⁺ ion flux non-invasive micro-test technique

HTML PDF 收藏

Development of a new method for RMR and Q classification method to optimize support system in tunneling

Asghar RAHMATI,Lohrasb FARAMARZI,Manouchehr SANEI

《结构与土木工程前沿（英文）》 2014年第8卷第4期页码 448-455 doi: 10.1007/s11709-014-0262-x

摘要： Rock mass classification system is very suitable for various engineering design and stability analysis. classification method is confirmed by Japan Highway Public Corporation that this method can figure out either strength or deformability of rock mass, further appropriating the amount of rock bolts, thickness of shotcrete, and size of pitch of steel ribs just after the blasting procedure. Based on these advantages of method, in this study, according to data of five deep and long tunnels in Iran, two equations for estimating the value of method from and classification systems were developed. These equations as a new method were able to optimize the support system for and classification systems. From classification and its application in these case studies, it is pointed out that the method for the design of support systems in underground working is more reliable than the and classification systems.

关键词： JH classification Q and RMR classification new method

HTML PDF 收藏

抗白粉病基因 Pm40i> 在我国“后 Pm21i> 时代”小麦育种中的重要作用 Perspective

唐圣雯,胡玉亭,钟胜福,罗培高

《工程（英文）》 2018年第4卷第4期页码 500-506 doi: 10.1016/j.eng.2018.06.004

摘要：

由小麦白粉菌[Blumeria graminis f. sp. tritici（Bgt）] 引起的小麦白粉病是一种重要的小麦叶部病害，对小麦的产量产生很大的影响。20 世纪80 年代，通过簇毛麦（Heuchera villosa）的6VS 染色体与小麦6AL 染色体易位将抗白粉病基因Pm21 转移到普通小麦中。最近，在一些地方发现了对Pm21 有毒的Bgt，虽然这些菌株的病理学特性还有待研究，但这一现象提醒小麦育种者应注意应用Pm21 的风险。来源于普通小麦与中间偃麦草（Thinopyrum intermedium）杂种后代的抗白粉病基因Pm40，被定位在小麦7BS 染色体上，对Bgt 具有广谱和持久的抗性。通过细胞学研究，并未在Pm40 的载体品种中发现大片段外缘染色体。过去几年的研究发现，Pm40 的载体品种具有优良的农艺性状。因此，我们相信在未来的育种工程中，Pm40 将会在Pm21 的抗性被克服之后起巨大的作用。另外，Pm21 和Pm40 都来源于外缘物种，这暗示着外源基因的抗性可能比小麦本身的基因更为持久和有效。

关键词：小麦白粉病 Pm21i> Pm40i> 外源基因内源抗性

HTML PDF 收藏

NiFeRuO_xi> nanosheets on Ni foam as an electrocatalyst for efficient

《化学科学与工程前沿（英文）》 2023年第17卷第11期页码 1698-1706 doi: 10.1007/s11705-023-2334-8

摘要： The electrocatalyst NiFeRuO_x/NF, comprised of NiFeRuO_x nanosheets grown on Ni foam, was synthesized using a hydrothermal process followed by thermal annealing. NiFeRuO_x/NF displays high electrocatalytic activity and stability for overall alkaline seawater splitting: 98 mV@ 10 mA∙cm⁻² in hydrogen evolution reaction, 318 mV@ 50 mA∙cm⁻² in oxygen evolution reaction, and a cell voltage of 1.53 V@ 10 mA∙cm⁻², as well as 20 h of durability. A solar-driven system containing such a bifunctional NiFeRuO_x/NF has an almost 100% Faradaic efficiency. The NiFeRuO_x coating around Ni foam is an anti-corrosion layer and also a critical factor for enhancement of bifunctional performances.

关键词： NiFeRuO_x nanosheets Ni foam electrocatalysis overall seawater splitting solar-driven system

HTML PDF 收藏

A toughness based deformation limit for X- and K-joints under brace axial tension

Bo GU,Xudong QIAN,Aziz AHMED

《结构与土木工程前沿（英文）》 2016年第10卷第3期页码 345-362 doi: 10.1007/s11709-016-0333-2

摘要： This study reports a deformation limit for the initiation of ductile fracture failure in fatigue-cracked circular hollow section (CHS) X- and K-joints subjected to brace axial tension. The proposed approach sets the deformation limit as the numerically computed crack driving force in a fatigue crack at the hot-spot location in the tubular joint reaches the material fracture toughness measured from standard fracture specimens. The calibration of the numerical procedure predicates on reported numerical computations on the crack driving force and previously published verification study against large-scale CHS X-joints with fatigue generated surface cracks. The development of the deformation limit includes a normalization procedure, which covers a wide range of the geometric parameters and material toughness levels. The lower-bound deformation limits thus developed follow a linear relationship with respect to the crack-depth ratio for both X- and K-joints. Comparison of the predicated deformation limit against experimental on cracked tubular X- and K-joints demonstrates the conservative nature of the proposed deformation limit. The proposed deformation limit, when extrapolated to a zero crack depth, provides an estimate on the deformation limits for intact X- and K-joints under brace axial loads.

关键词： circular hollow section (CHS) tubular joint fracture failure deformation limit J-integral

HTML PDF 收藏

2014—2016年食品动物源RE-cmeABCi>阳性弯曲菌流行与耐药性现状 Article

刘德俊, 刘蔚雯, 李星, 姚红, 沈张奇, 汪洋, 沈建忠

《工程（英文）》 2020年第6卷第1期页码 34-39 doi: 10.1016/j.eng.2019.10.013

摘要：

弯曲菌是引起人类胃肠炎的一类重要食源性致病菌。RE-CmeABC是近年来弯曲菌中新发现的一种增强型耐药外排泵，可介导对兽医和人医临床治疗弯曲菌感染的重要药物，如氟喹诺酮类、酰胺醇类、大环内酯类及四环素类等药物的高水平耐药，而目前尚未有对该外排泵的大范围流行病学调查。因此，本研究调查了2014—2016年连续三年间我国山东、上海和广东等三个重点养殖区食品动物源RE-cmeABC阳性弯曲菌的流行与耐药性现状。结果显示，在1088株弯曲菌（931株结肠弯曲菌与157株空肠弯曲菌）中共检测出122株（11.2%）RE-cmeABC阳性菌株，包括111株（70.7%）空肠弯曲菌与11株（1.2%）结肠弯曲菌，空肠弯曲菌中RE-cmeABC的阳性率显著高于结肠弯曲菌。111株RE-cmeABC阳性空肠弯曲菌与46株RE-cmeABC阴性空肠弯曲菌相比在氟苯尼考、克林霉素和红霉素的耐药率上具有显著差异（P < 0.05），而在环丙沙星、四环素和庆大霉素的耐药率上无显著差异。然而，携带RE-cmeABC的菌株可以使环丙沙星与四环素对弯曲菌的MIC值分布趋于更高水平范围。脉冲场凝胶电泳分型（PFGE）结果显示RE-cmeABC阳性菌株在上海和广东地区以水平传播为主，在山东地区以克隆传播为主；三株分离于上海和广东的阳性菌为同一克隆型，4株分离于上海和山东的阳性菌为同一克隆型。本研究表明RE-cmeABC已在我国食品动物源弯曲菌中广泛流行，对公共卫生安全具有潜在威胁。

关键词： RE- cmeABC i> 弯曲菌环丙沙星氟苯尼考

HTML PDF 收藏

A highly efficient methodology for the preparation of

Yongxin Zhang, Shucheng Wang, Yaodong Huang

《化学科学与工程前沿（英文）》 2021年第15卷第3期页码 679-686 doi: 10.1007/s11705-020-1979-9

摘要： A convenient and highly efficient method is described for the synthesis of -methoxycarbazole derivatives, including those with sterically demanding, benzannulated, or strongly electron-donating or -withdrawing substituents. Various -methoxycarbazole derivatives were directly prepared in good-to-moderate yields by the Pd (dba) CHCl /9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene-catalyzed reactions of the corresponding dibromobiphenyl compounds and methoxya-mine. Based on this methodology, the first total synthesis of 3,3′-[oxybis(methylene)]bis(9-methoxy-9 -carbazole), an antimicrobial dimeric carbazole alkaloid previously isolated from the stem bark of , was achieved in 18% yield over seven steps from 1,2-dibromobenzene.

关键词： N-methoxyl carbazole dimeric N-methoxyl carbazole alkaloid total synthesis double N-arylation of methoxyamine

HTML PDF 收藏

通过 B i>位Ta置换对 AB i> O₄型EuNbO₄的热学和力学性质进行优化 Article

陈琳, 冯晶

《工程（英文）》 2020年第6卷第2期页码 177-184 doi: 10.1016/j.eng.2019.12.006

摘要： /em>位Ta置换可以有效提高EuNbO₄陶瓷的杨氏模量和热膨胀系数（TEC），且其最大值分别为169 GPa和1.12×10⁻⁵ K⁻¹（1200 ℃）； EuNbO₄陶瓷的热导率被降低至1.52 W·K^–1·m^{关键词：

热障涂层，稀土铌酸盐，置换，热导率，热膨胀系数，杨氏模量

HTML

PDF

收藏}

Traces and echoes of De Architecturai> by Marcus Vitruvius Pollio in the work of Xu Guangqi in 17th

Michela CIGOLA,Yibing FANG

《机械工程前沿（英文）》 2016年第11卷第1期页码 3-11 doi: 10.1007/s11465-015-0359-5

摘要：

This study aims to investigate the role played by Xu Guangqi (1562–1633), minister of the Ming Dynasty, in the development of European scientific and technical knowledge in China between the 16th and 17th centuries by analyzing a book of Western technology that he wrote, namely, Taixi Shuifa (On Western Hydraulics). Several Western books related to machine knowledge are searched to trace the source of the illustrations in Taixi Shuifa. We found that Archimedes’ screw and Ctesibius’ machine, which are included in Vitruvius’ De Architectura volumes, also appear in the work of Xu Guangqi.

关键词： Vitruvius’ De Architectura Xu Guangqi’s Taixi Shuifa Jesuit missionaries Italian Renaissance drawing representation

HTML PDF 收藏

Accounting for the uncertainties in the estimation of average shear wave velocity using – correlations

《结构与土木工程前沿（英文）》 2021年第15卷第5期页码 1199-1208 doi: 10.1007/s11709-021-0749-1

摘要： Site-specific seismic hazard analysis is crucial for designing earthquake resistance structures, particularly in seismically active regions. Shear wave velocity ( V _S) is a key parameter in such analysis, although the economy and other factors restrict its direct field measurement in many cases. Various V _S–SPT– N correlations are routinely incorporated in seismic hazard analysis to estimate the value of V _S. However, many uncertainties question the reliability of these estimated V _S values. This paper comes up with a statistical approach to take care of such uncertainties involved in V _S calculations. The measured SPT– N values from all the critical boreholes were converted into statistical parameters and passed through various correlations to estimate V _S at different depths. The effect of different soil layers in the boreholes on the Vs estimation was also taken into account. Further, the average shear wave velocity of the top 30 m soil cover ( V _S30) is estimated after accounting for various epistemic and aleatoric uncertainties. The scattering nature of the V _S values estimated using different V _S– N correlations was reduced significantly with the application of the methodology. Study results further clearly demonstrated the potential of the approach to eliminate various uncertainties involved in the estimation of V _S30 using general and soil-specific correlations.

关键词： uncertainties V _S– N correlations V _S30 SPT data statistical methodology