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Time of flight improved thermally grown oxide thickness measurement with terahertz spectroscopy

《机械工程前沿（英文）》 2022年第17卷第4期 doi: 10.1007/s11465-022-0705-3

摘要： As a nondestructive testing technique, terahertz time-domain spectroscopy technology is commonly used to measure the thickness of ceramic coat in thermal barrier coatings (TBCs). However, the invisibility of ceramic/thermally grown oxide (TGO) reflective wave leads to the measurement failure of natural growth TGO whose thickness is below 10 μm in TBCs. To detect and monitor TGO in the emergence stage, a time of flight (TOF) improved TGO thickness measurement method is proposed. A simulative investigation on propagation characteristics of terahertz shows the linear relationship between TGO thickness and phase shift of feature wave. The accurate TOF increment could be acquired from wavelet soft threshold and cross-correlation function with negative effect reduction of environmental noise and system oscillation. Thus, the TGO thickness could be obtained efficiently from the TOF increment of the monitor area with different heating times. The averaged error of 1.61 μm in experimental results demonstrates the highly accurate and robust measurement of the proposed method, making it attractive for condition monitoring and life prediction of TBCs.

关键词： thermal barrier coatings thermally grown oxide terahertz spectroscopy time of flight

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Transient imaging with a time-of-flight cameraand its applications

Jing-yu LIN, Ri-hui WU, Hong-man WANG, Ye-bin LIU

《信息与电子工程前沿（英文）》 2017年第18卷第9期页码 1268-1276 doi: .org/10.1631/FITEE.1700556

摘要： Transient imaging is a technique in photography that recordsthe process of light propagation before it reaches a stationary statesuch that events at the light speed level can be observed. In thisreview we introduce three main models for transient imaging with atime-of-flight (ToF) camera: correlation model, frequency-domain model,and compressive sensing model. Transient imaging applications usuallyinvolve resolving the problem of light transport and separating thelight rays arriving along different paths. We discuss two of the applications:imaging objects inside scattering media and recovering both the shapeand texture of an object around a corner.

关键词： Transient imaging Time-of-flight(ToF) camera Scattering media Around corners

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Determination of persistent organic pollutants by gas chromatography/laser multiphoton ionization/time-of-flight

Osamu SHITAMICHI, Taiki MATSUI, Yamei HUI, Weiwei CHEN, Totaro IMASAKA

《环境科学与工程前沿（英文）》 2012年第6卷第1期页码 26-31 doi: 10.1007/s11783-011-0374-7

摘要： An authentic mixture of polychlorinated biphenyls was measured using a short wide-bore capillary column for the group separation of major components present in an actual sample of Kanechlor. The limits of detection were improved by ca. 2 fold in comparison with those obtained using a conventional capillary column, since the retention time was reduced and the amount of analytes introduced into the mass spectrometer per unit time could be increased. On the other hand, surface-water and sediment samples containing polycyclic aromatic hydrocarbons (PAHs) were collected from the river located in the vicinity of a waste water treatment plant. Even acenaphthylene, a minor component of the mixture could be measured for the sediment sample, and the concentrations were determined for several heavy PAHs. As demonstrated, a technique involving laser multiphoton ionization/time-of-flight mass spectrometry was useful as a sensitive and selective analytical tool for the trace analysis of persistent organic pollutants in an environmental sample.

关键词： polychlorinated biphenyls (PCBs) polycyclic aromatic hydrocarbons (PAHs) laser multiphoton ionization/time-of-flight mass spectrometry (MPI/TOF-MS)

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采用飞行时间相机的瞬态成像及其应用

Jing-yu Lin, Ri-hui Wu, Hong-man Wang, Ye-bin Liu,jylin@gxu.edu.cn,liuyebin@tsinghua.edu.cn

《信息与电子工程前沿（英文）》 2017年第18卷第9期页码 1268-1276 doi: 10.1631/FITEE.1700556

摘要：介绍了采用飞行时间（time-of-flight, ToF）相机进行瞬态成像的三种数学模型，即相关函数模型、频域模型和压缩感知模型。瞬态图像应用主要基于光传输解析和不同光路光线分离。

关键词：瞬态成像；飞行时间（time-of-flight ToF）；散射介质；拐角遮挡

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Single particle analysis of ambient aerosols in Shanghai during the World Exposition, 2010: two case studies

Shikang TAO, Xinning WANG, Hong CHEN, Xin YANG, Mei LI, Lei LI, Zhen ZHOU

《环境科学与工程前沿（英文）》 2011年第5卷第3期页码 391-401 doi: 10.1007/s11783-011-0355-x

摘要： A TSI Model 3800 aerosol time-of-flight mass spectrometer (ATOFMS) was deployed for single-particle analysis in Shanghai during the World Exposition (EXPO), 2010. Measurements on two extreme cases: polluted day (1st May) and clean day (25th September) were compared to show how meteorological conditions affected the concentration and composition of ambient aerosols. Mass spectra of 90496 and 50407 particles were analyzed respectively during the two sampling periods. The ART-2a neural network algorithm was applied to sort the collected particles. Seven major classes of particles were obtained: dust, sea salt, industrial, biomass burning, organic carbon (OC), elementary carbon (EC), and NH -rich particles. Number concentration of ambient aerosols showed a strong anti-correlation with the boundary layer height variation. The external mixing states of aerosols were quite different during two sampling periods because of different air parcel trajectories. Number fraction of biomass burning particles (43.3%) during polluted episode was much higher than that (21.6%) of clean time. Air parcels from the East China Sea on clean day diluted local pollutant concentration and increased the portion of sea salt particle dramatically (13.3%). The large contribution of biomass burning particles in both cases might be an indication of a constant regional background of biomass burning emission. Mass spectrum analysis showed that chemical compositions and internal mixing states of almost all the particle types were more complicate during polluted episode compared with those observed in clean time. Strong nitrate signals in the mass spectra suggested that most of the particles collected on polluted day had gone through some aging processes before reaching the sampling site.

关键词： ambient aerosol aerosol time-of-flight mass spectrometer Shanghai world exposition

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航空航天技术与力学

陈士橹

《中国工程科学》 2003年第5卷第3期页码 25-26

摘要：

文章论述了航空航天技术发展与力学学科发展的依存关系，讨论了力学学科间的交叉及交叉学科的产生，重点介绍了飞行力学与空气动力学、结构力学、一般力学、自动控制等学科间的关系，进而讨论了飞行力学的分支——弹性飞行器动力学。

关键词：空气动力学结构力学一般力学自动控制飞行力学弹性飞行器动力学

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Characterization of submicron aerosols in the urban outflow of the central Pearl River Delta region of China

Zhaoheng GONG, Zijuan LAN, Lian XUE, Liwu ZENG, Lingyan HE, Xiaofeng HUANG

《环境科学与工程前沿（英文）》 2012年第6卷第5期页码 725-733 doi: 10.1007/s11783-012-0441-8

摘要： Submicron aerosol particles (with aerodynamic diameters less than 1 μm, PM ) were sampled and measured in Heshan, an urban outflow site of Guangzhou megacity in Pearl River Delta in South China, using an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) in November 2010 during 2010 Guangzhou Asian Games. The mean PM mass concentration measured was 47.9±17.0 μg·m during the campaign, with organic aerosol (OA) and sulfate being the two dominant species, accounting for 36.3% and 20.9% of the total mass, respectively, followed by black carbon (17.1%, measured by an aethalometer), nitrate (12.9%), ammonium (9.6%) and chloride (3.1%). The average size distributions of the species (except black carbon) were dominated by an accumulation mode peaking at ~550 nm. Calculations based on high-resolution organic mass spectrum showed that, C, H, O and N on average contributed 58.1%, 7.3%, 30.7%, and 3.9% to the total organic mass, respectively. The average ratio of organic mass over organic carbon mass (OM/OC) was 1.73±0.08. Four components of OA were identified by the Positive Matrix Factorization (PMF) analysis, including a hydrocarbon-like (HOA), a biomass burning (BBOA) and two oxygenated (SV-OOA and LV-OOA) organic aerosol components, which on average accounted for 18.0%, 14.3%, 28.8% and 38.9% of the total organic mass, respectively.

关键词： organic aerosol high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) positive matrix factorization

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Response surface regression analysis on FeCrBSi particle in-flight properties by plasma spray

Runbo MA,Lihong DONG,Haidou WANG,Shuying CHEN,Zhiguo XING

《机械工程前沿（英文）》 2016年第11卷第3期页码 250-257 doi: 10.1007/s11465-016-0401-2

摘要：

This work discusses the interactive effects between every two of argon flow rate, voltage, and spray distance on in-flight particles by plasma spray and constructs models that can be used in predicting and analyzing average velocity and temperature. Results of the response surface methodology show that the interactive effects between voltage and spray distance on particle in-flight properties are significant. For a given argon flow rate, particle velocity and temperature response surface are obviously bending, and a saddle point exists. With an increase in spray distance, the interactive effects between voltage and argon flow rate on particle in-flight properties appear gradually and then weaken. With an increase in voltage, the interactive effects between spray distance and argon flow rate on particle in-flight properties change from appearing to strengthening and then to weakening.

关键词： particle velocity particle temperature interactive effects response surface

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β-粒子在穿越铜狭缝中的横向台阶分布

朱永强,郝建宇

《中国工程科学》 2008年第10卷第8期页码 81-86

摘要：

文章研究了电子高速运动时所产生的横向振动。实验方法是利用半圆聚焦β-谱仪上90Sr源β-粒子在不同磁场下对于相同弯曲半径下β-粒子具有不同的能量和动量的特性，研究这些β-粒子在通过不同宽度的铜狭缝（厚8 mm）时的粒子数n和铜狭缝宽度δ的函数关系，发现不管β-粒子具有什么能量和动量，都具有横向运动的趋势和在铜狭缝中出现了台阶分布。其原因可能是β-粒子本身具有横向振幅A和周围真空起伏能量的相互作用。

关键词： β-粒子的横向振动铜狭缝宽度横向台阶分布

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HY-2A卫星雷达高度计设计及其在轨工作结果

许可,刘和光,姜景山

《中国工程科学》 2013年第15卷第7期页码 25-32

摘要：

海洋二号（HY-2A）卫星是我国第一颗海洋动力环境卫星，雷达高度计是HY-2A卫星的主载荷之一，发射入轨后仪器工作正常，并获得了大量有效的观测数据。该仪器在20 m有效波高条件下测高精度达到了4 cm，在4 m有效波高条件下测高精度达到了2 cm，其产品精度接近Jason-2卫星高度计。本文就HY-2A卫星雷达高度计系统设计和在轨初步结果进行论述。

关键词：雷达高度计 HY-2A卫星在轨工作

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基于张量因子分解框架的航班延误模式分析 Article

张明远, 陈莘文, 孙立君, 杜文博, 曹先彬

《工程（英文）》 2021年第7卷第4期页码 465-472 doi: 10.1016/j.eng.2020.08.024

摘要：

在空中交通管理和民航机场运营过程中，从过去的运营中获得的经验对于设计合理的策略至关重要。因此，本文使用大量时空飞行数据来识别相似的航空交通和延误模式，这对于更好地了解航空系统和制订管理决策至关重要。但是，由于数据集隐含了复杂的依赖关系以及高维时空之间的交互作用，因此挖掘数据中的重要特征和模式非常具有挑战性。本文提出了高维历史飞行数据的张量因子分解框架。我们通过潜在类别分析模型，并使用2014—2017年中国224个机场的空中交通运行数据证明了该框架的有效性。研究发现每个维度可以清晰地代表不同的运行模式。为了证明这些模式的有效性，我们创建了一个估计模型，该模型可实现对航班延误程度的初步判断。上述结果可以根据历史情景获得的经验，帮助机场运营商和空中交通管理人员更好地了解空中交通和延误模式。

关键词：空中交通管理航班延误潜在类别模型张量分解

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光纤传感技术在飞行器结构变形监测中的应用 Review

祝连庆, 孙广开, 包为民, 尤政, 孟凡勇, 董明利

《工程（英文）》 2022年第16卷第9期页码 39-55 doi: 10.1016/j.eng.2021.02.022

摘要：

基于光纤传感网络的飞行器结构变形监测一直是航空航天领域的研究热点。经过近30年来的研究发展，国内外研究人员在相关理论和方法、技术与系统和试验测试方面已经取得了较大进展，推动了光纤传感技术从实验室研究向工程应用的演进。但是，目前在实际应用中仍然存在若干问题，限制了该技术的应用发展，亟待探讨解决方法。为此，梳理了飞行器结构变形监测的研究发展历程，分析了光纤传感监测的主要技术类型、技术优缺点、机载适用性、变形重构算法和典型应用案例，指出了当前需要研究解决的关键问题和工程应用的主要演进范式，并结合新材料、标准化和智能化等内容探讨了未来发展方向。

关键词：光纤传感技术变形监测结构健康监测飞行器航空航天

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General expression for linear and nonlinear time series models

Ren HUANG, Feiyun XU, Ruwen CHEN

《机械工程前沿（英文）》 2009年第4卷第1期页码 15-24 doi: 10.1007/s11465-009-0015-z

摘要： The typical time series models such as ARMA, AR, and MA are founded on the normality and stationarity of a system and expressed by a linear difference equation; therefore, they are strictly limited to the linear system. However, some nonlinear factors are within the practical system; thus, it is difficult to fit the model for real systems with the above models. This paper proposes a general expression for linear and nonlinear auto-regressive time series models (GNAR). With the gradient optimization method and modified AIC information criteria integrated with the prediction error, the parameter estimation and order determination are achieved. The model simulation and experiments show that the GNAR model can accurately approximate to the dynamic characteristics of the most nonlinear models applied in academics and engineering. The modeling and prediction accuracy of the GNAR model is superior to the classical time series models. The proposed GNAR model is flexible and effective.

关键词： linear and nonlinear autoregressive model system identification time series analysis

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Run-time system based on LinSERCANS and Soft-PLC

Cunfeng KANG, Chong WANG, Chunmin MA, Xudong HUANG, Renyuan FEI

《机械工程前沿（英文）》 2009年第4卷第2期页码 120-124 doi: 10.1007/s11465-009-0019-8

摘要： Soft-PLC with open architecture is the direction of development in industrial automation. This paper discusses the method of communication between the interface functions of LinSERCANS under RTLinux and the external library of Soft-PLC under Windows. Based on the API HOOK theory, the communication between the interface functions of LinSERCANS and the external libraries of Soft-PLC is set up and it solves the calling functions of dynamic link libraries in different operation systems. It is able to combine LinSERCANS with the Soft-PLC, and a run-time system is developed based on the interface technology of the serial real-time communication system (SERCOS) and technology of soft-PLC. This run-time system has been used in all electronic injection molding machines and works very well.

关键词： Soft-PLC run-time system LinSERCANS dynamic link libraries

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某型飞机双座弹射轨迹仿真分析

王伟,封文春,林贵平

《中国工程科学》 2010年第12卷第1期页码 86-90

摘要：

以HTY-8座椅为原型，建立了具有轨迹发散作用的仿真模型，通过仿真，比较分析了发散火箭在不同冲量和不同弹射条件下对弹射轨迹的影响。仿真结果表明，在零速度或速度较低的弹射条件下，采用发散火箭是必要的。在中高速弹射条件下，由于前后座椅弹射具有一定的时间差，X方向轨迹离散，前后座椅弹射轨迹发散，发散火箭的作用并不明显，尚需进一步分析人椅分离后先弹射的座椅的运动轨迹。在不利姿态弹射条件下，横滚时发散火箭作用并不明显，俯冲时则能够起到轨迹发散作用。

关键词：弹射座椅双座弹射轨迹发散弹射仿真