Experimental Thermal and Fluid Science最新文献

{"title":"Triad interactions investigated by dual wave component injection","authors":"Preben Buchhave ,&nbsp;Mengjia Ren ,&nbsp;Clara M. Velte","doi":"10.1016/j.expthermflusci.2024.111239","DOIUrl":"https://doi.org/10.1016/j.expthermflusci.2024.111239","url":null,"abstract":"<div><p>The study of the exchange of momentum and energy between wave components of the turbulent velocity field, the so-called triad interactions, offers a unique way of visualizing and describing turbulence. Most often, this study has been carried out by direct numerical simulations or by power spectral measurements. Due to the complexity of the problem and the great range of velocity scales in high Reynolds number developed turbulence, direct measurements of the interaction between the individual wave components have been rare. In the present work, we present measurements and related computations of triad interactions between controlled wave components injected into an approximately laminar and uniform flow from an open wind tunnel by vortex shedding from two rods suspended into the flow. This results in two-dimensional interactions of three-dimensional turbulence, which makes the analysis of the triadic interactions considerably less complex to analyze than in a fully developed three-dimensional flow. With the information obtained from the computations, we are able to isolate the individual triad interactions contributing to the generated frequency components as the flow develops downstream as well as understanding, mapping out and predicting the strengths of these interactions. The analysis also provides the time constants governing the development of higher order frequency components. We are thus able to see the pattern of frequency combinations, the strengths of the individual mode combinations and the time sequence in which they occur. Any of the higher order combinations is not just the result of a single term in the Navier–Stokes Equation, but a combination of various previous combinations occurring with different strengths and in a varied pattern of generation. The combination of these experiments and computations thus provide unique insight into the inner workings of turbulence and shows how the nonlinear term in the Navier–Stokes equation on average forces the energy towards higher frequencies, which is the reason for the so-called energy cascade.</p></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0894177724001080/pdfft?md5=c7a4da8b9f34af132d57f549514a9f22&pid=1-s2.0-S0894177724001080-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141244609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Data repairing and resolution enhancement using data-driven modal decomposition and deep learning","authors":"Ashton Hetherington ,&nbsp;Daniel Serfaty ,&nbsp;Adrián Corrochano ,&nbsp;Julio Soria ,&nbsp;Soledad Le Clainche","doi":"10.1016/j.expthermflusci.2024.111241","DOIUrl":"https://doi.org/10.1016/j.expthermflusci.2024.111241","url":null,"abstract":"<div><p>This paper introduces a new series of methods which combine modal decomposition algorithms, such as singular value decomposition and high-order singular value decomposition, and deep learning architectures to repair, enhance, and increase the quality and precision of numerical and experimental data. A combination of two- and three-dimensional, numerical and experimental datasets are used to demonstrate the reconstruction capacity of the presented methods, showing that these methods can be used to reconstruct any type of dataset, showing outstanding results when applied to highly complex data, which is noisy. The combination of benefits of these techniques results in a series of data-driven methods which are capable of repairing and/or enhancing the resolution of a dataset by identifying the underlying physics that define the data, which is incomplete or under-resolved, filtering any existing noise. These methods and the <em>Python</em> codes are included in the first release of ModelFLOWs-app.<span>¹</span></p></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0894177724001109/pdfft?md5=858456a15bbabb6c56a44d121e8995ed&pid=1-s2.0-S0894177724001109-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141164235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Internal waves generated from asymmetric topographies","authors":"K. Hakes,&nbsp;J. Crockett","doi":"10.1016/j.expthermflusci.2024.111240","DOIUrl":"10.1016/j.expthermflusci.2024.111240","url":null,"abstract":"<div><p>Previous experimental and theoretical research on tidally generated internal waves over oceanic topography has often used symmetric topographic profiles. However, due to the complex nature of real ocean topography, the effect of asymmetry cannot be overlooked. Studies have shown that topographic complexities, including asymmetry, can have a significant impact on internal wave generation, but topographic asymmetry has not yet been explored in a systematic manner. This work presents a comparison of tidally generated internal waves from nine different two-dimensional asymmetric topographies, consisting of a steeper Gaussian curve on one side, and a wider Gaussian curve on the other. The amplitude of the wider curve varies from 60% of the steeper curve to its equivalent. Two oscillation frequencies are tested. Kinetic energy density in tidally generated internal waves on each side of the topography is compared qualitatively and quantitatively, in both physical and Fourier space. When compared to similar symmetric topographies, waves generated by the asymmetric topographies varied distinctly in both magnitude and wavenumber distribution of kinetic energy density. Waves on the relatively steep side of the topography contain up to 50% more kinetic energy than on the wider side. However, there is very little kinetic energy at the higher wavenumbers associated with the steeper topography. Instead, the internal wavefield is dominated by lower wavenumbers, 50%–90% of the kinetic energy density is contained in wavelengths corresponding to the wider side of the topography. Decreasing the amplitude of the wider curve does not make an appreciable difference in the kinetic energy density spectrum. Thus, the differences quantified here are due solely to changing slope and show the effect which relatively slight asymmetry has on internal wave generation.</p></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141141492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Threshold of Keulegan–Carpenter instability within a 6 × 6 rod bundle","authors":"Lorenzo Longo ,&nbsp;Roberto Capanna ,&nbsp;Guillaume Ricciardi ,&nbsp;Philippe M. Bardet","doi":"10.1016/j.expthermflusci.2024.111231","DOIUrl":"10.1016/j.expthermflusci.2024.111231","url":null,"abstract":"<div><p>The literature is rich in fluid–structure interaction studies of a single rod in oscillating fluid (or the reciprocate), however, there is a dearth of experimental data for rod bundle oscillation, particularly if the bundle is in a confined environment. The presence of the fluid surrounding the moving solid is modeled with force coefficients such as inertial and drag. In case of small amplitudes oscillating flow, these force coefficients depend non-linearly on the Keulegan–Carpenter number <span><math><mrow><mi>K</mi><mi>C</mi></mrow></math></span>. The dependence present different regimes, separated by threshold <span><math><mrow><mi>K</mi><mi>C</mi></mrow></math></span> numbers. At different regimes correspond different fluid dynamics, hence different force coefficients. The aim of this paper is to experimentally investigate the fluid dynamic for a rod bundle oscillating in a stagnant fluid. The velocity fields have been measured with Particle Image Velocimetry (PIV). Both the rod bundle and the fluid have the same refractive index, which allow to measure the velocity fields within the rod bundle in an non intrusive manner. The bundle is hosted in a double tank, immersed in a refractive index matched solution and placed on an earthquake shake table. The shake table sets the bundle into motion along a single direction.</p><p>Data enable the identification of a threshold effect in the fluid response to the oscillating assembly. This threshold effect is due to the formation of vortexes in the fluid. Data show a clear trend on how the development of turbulence occurs firstly inside the rod assembly and then in the bypass between the assembly and the tank wall. The experimental results indicate the presence of a viscous boundary layer developed along the rod, above the threshold <span><math><mrow><mi>K</mi><mi>C</mi></mrow></math></span>. The results presented in this paper represent a step forward the comprehension of the damping effect induced by the fluid at different oscillating amplitudes and frequencies, due to different <span><math><mrow><mi>K</mi><mi>C</mi></mrow></math></span> regimes.</p></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0894177724001006/pdfft?md5=93d8905559a46a95ed58c1797c4b2114&pid=1-s2.0-S0894177724001006-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141026828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-domain analysis and prediction of inductively coupled plasma jet dynamics via high-speed imaging of visible light emission","authors":"Lorenzo Capponi,&nbsp;Alberto Padovan,&nbsp;Gregory S. Elliott,&nbsp;Marco Panesi,&nbsp;Daniel J. Bodony,&nbsp;Francesco Panerai","doi":"10.1016/j.expthermflusci.2024.111232","DOIUrl":"https://doi.org/10.1016/j.expthermflusci.2024.111232","url":null,"abstract":"<div><p>Inductively coupled plasma wind tunnels are crucial for replicating hypersonic flight conditions in ground testing. Achieving the desired conditions (e.g., stagnation-point heat fluxes and enthalpies during atmospheric reentry) requires a careful selection of operating inputs, such as mass flow, gas composition, nozzle geometry, torch power, chamber pressure, and probing location along the plasma jet. The study presented herein focuses on the influence of the torch power and chamber pressure on the plasma jet dynamics within the 350 kW Plasmatron X ICP facility at the University of Illinois at Urbana-Champaign. A multi-domain analysis of the jet behavior under selected power-pressure conditions is presented in terms of emitted light measurements collected using high-speed imaging. We then use Gaussian Process Regression to develop a data-informed learning framework for predicting Plasmatron X jet profiles at unseen pressure and power test conditions. Understanding the physics behind the dynamics of high-enthalpy flows, particularly plasma jets, is the key to properly design material testing, perform diagnostics, and develop accurate simulation models.</p></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141068898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat transport during drop impact onto a heated wall covered with an electrospun nanofiber mat: The influence of wall superheat, impact velocity, and mat thickness","authors":"A. Gholijani,&nbsp;T. Gambaryan-Roisman,&nbsp;P. Stephan","doi":"10.1016/j.expthermflusci.2024.111230","DOIUrl":"https://doi.org/10.1016/j.expthermflusci.2024.111230","url":null,"abstract":"<div><p>Nanofiber surface coating is a promising method for the enhancement of heat transfer during spray cooling. In the present work, the drop dynamics as well as local and overall heat transfer during single drop impact onto a heated wall covered with a polyacrylonitrile (PAN) nanofiber mat are investigated to obtain insight into the mechanisms governing the heat transport enhancement. The influence of wall superheat, drop impact velocity, and mat thickness on the hydrodynamics and heat transfer from the heated wall to the fluid is studied. The experiments were conducted inside a temperature-controlled test cell with a pure vapor atmosphere maintained with refrigerant FC<span><math><mrow><mo>−</mo><mn>72</mn></mrow></math></span> (perfluorohexane). The temperature field at the solid–fluid interface was observed with a high-speed infrared camera, and the heat flux field was derived by solving a three-dimensional transient heat conduction equation within the substrate. The presence of the nanofiber mat on the heater surface suppresses the drop receding phase due to the pinning of the contact line at the end of the spreading phase. Two different heat transfer scenarios are observed depending on the wall superheat and drop impact velocity: scenario (I), in which the liquid drop completely penetrated through the porous nanofiber mat and made contact with the heater surface; and scenario (II) in which the vapor produced inside the pores of the nanofiber mat prevented the liquid drop from touching the heater surface. In scenario (I), an up 450% heat flow enhancement during the sessile drop evaporation stage has been observed. In scenario (II), a 80% heat flow enhancement at this stage has been registered.</p></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0894177724000992/pdfft?md5=d42e2d6bc76c49b4a4c0b40212f652d1&pid=1-s2.0-S0894177724000992-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141164234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simultaneous measurement of thermal conductivity and emissivity of micro/nanomaterials","authors":"Jinyu Chen,&nbsp;Jie Tang,&nbsp;Jinhui Liu","doi":"10.1016/j.expthermflusci.2024.111229","DOIUrl":"https://doi.org/10.1016/j.expthermflusci.2024.111229","url":null,"abstract":"<div><p>Although thermal conductivity of micro/nano scale material has been readily measured, the high specific surface area leads to non-negligible radiative heat transfer. Here, a method for simultaneous measurement of intrinsic thermal conductivity and emissivity of micro/nano materials was developed and verified. The physical model of this measurement principle consisted of two parallel platinum wires, which serve as both heaters and heat flux meters. Thermal conductivity and emissivity can be derived by comparing the changes in the average temperature rise of the heater and sensor platinum wires before and after attaching the test sample. The thermal conductivity and emissivity of an individual platinum wire were determined to 71.7 W/(m·K) and 0.14, which are consistent with the reference values. Subsequently, the thermal conductivity and emissivity of the polymer composite fiber were measured to be 1.45 W/(m·K), 0.73 and 1.87 W/(m·K), 0.8 at different composite filler concentrations. In principle, this method is applicable for accurately measuring the thermal transport properties of any micro/nano wires using appropriate sensors.</p></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140894980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Liquid film burst caused by perpendicularly blowing gas jet","authors":"Shangning Wang,&nbsp;Yilong Li,&nbsp;Yijia Zhang,&nbsp;Shuyi Qiu,&nbsp;Xuesong Li,&nbsp;Min Xu","doi":"10.1016/j.expthermflusci.2024.111228","DOIUrl":"https://doi.org/10.1016/j.expthermflusci.2024.111228","url":null,"abstract":"<div><p>Blowing gas perpendicularly onto a liquid film may lead to various kinds of film deformations. When the jet is steady and mild, a protrusion structure will appear on the film and stretches in length, as jet velocity continue to increase, separated bubbles will detach from the protruded surface. Compared with continuously blowing gentle gas jets, short duration pulsed strong jets are more realistic and generally existing, yet the in-depth mechanism studies are insufficient, thus need further investigation. We have observed that the liquid film protrusion tends to stretch to a critical length then burst into tiny droplets when blown by the pulsed jet. After theoretical analysis, we discover that during the stretching process, rather than the jet velocity that was presumed as the driving factor, the two physical properties of the fluid, namely the surface tension and viscosity, play the dominant role to cause the structure collapsing. The critical burst length of the protrusion structure correlates with the ratio of these two properties. We conducted experiments using various test fluids, gas nozzle diameters, and jet velocities. The experimental results confirmed our theoretical analysis. This discovery provides a critical insight into the physics of liquid film deformation and atomization under gaseous crossflow, which can be commonly seen in fuel injection and aerosol droplet generation related fields.</p></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140894979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study of a separated shear layer transition under acoustic excitation","authors":"V. Sokolenko ,&nbsp;A. Dróżdż ,&nbsp;Z. Rarata ,&nbsp;S. Kubacki ,&nbsp;W. Elsner","doi":"10.1016/j.expthermflusci.2024.111227","DOIUrl":"https://doi.org/10.1016/j.expthermflusci.2024.111227","url":null,"abstract":"<div><p>The paper discusses experimental results on the effect of broadband acoustic excitation on laminar-to-turbulent transition in a separated shear layer developing on a flat plate subjected to an adverse pressure gradient (APG) and freestream turbulence level equal to <em>Tu</em> ≅ 1 %. The study encompasses the influence of Reynolds number (<em>Re_x</em> = 185 000 and 370 000) and sound pressure level (SPL). The inherent complexity of the problem is simplified by providing an acoustic excitation from a controlled source (loudspeaker), acting on the boundary layer developing on the flat plate with a given streamwise pressure gradient. Two types of instabilities were identified in the pre-transitional boundary layer in unexcited flows. One was related to the inviscid Kelvin-Helmholtz (K-H) instability, while the second one was associated with formation of streamwise-oriented Klebanoff streaks (so-called Klebanoff mode).</p><p>In the low Reynolds number case (<em>Re_x</em> = 185 000), the K-H was responsible for transition onset, while in the high Reynolds number flow (<em>Re_x</em> = 370 000), the Klebanoff distortions dominated the turbulent breakdown with the minor effect of the K-H instability. In addition to the naturally developing boundary layer, the flow was exposed to a pink noise characterized by SPL = 125 dB and 135 dB. In the low Reynolds number case, the acoustic excitation enhanced the K-H instability. It resulted in an earlier laminar-to-turbulent transition in case with higher sound pressure level (135 dB). In the high Reynolds number flow, the acoustic excitation enhanced the mixed-type transition mechanism with dominant role of the Klebanoff streaks. Shrinking or complete suppression of the separation bubbles was observed, depending on the applied sound pressure level (125 and 135 dB).</p></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140842736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of pressure fluctuation distribution on a flat wall behind supported square cylinder with pressure-sensitive paint","authors":"Akitoshi Matsui ,&nbsp;Chiaki Kawase ,&nbsp;Yosuke Sugioka ,&nbsp;Keisuke Asai ,&nbsp;Taku Nonomura","doi":"10.1016/j.expthermflusci.2024.111226","DOIUrl":"10.1016/j.expthermflusci.2024.111226","url":null,"abstract":"<div><p>The pressure fluctuation distribution on the floor surface behind a supported square cylinder in a turbulent boundary layer was measured by using pressure-sensitive paint (PSP). Specifically, the accuracy and frequency response of PSP at a Mach number around <em>M</em> = 0.3 were examined. Four square cylinders with different dimensions were investigated in the same turbulent boundary layer, and the detailed relationship between these conditions and Kármán vortex shedding structures was discussed. The values measured with PSP had a similar trend to those measured with a pressure transducer at up to 5 kHz. The peak power spectral density (PSD) of the pressure fluctuations due to Kármán vortex shedding was observed within an error of approximately 30 % at up to frequencies greater than 3 kHz. Moreover, the peak frequency of Kármán vortex shedding was found to decrease with the cylinder height in a manner similar to a previous empirical equation for the Strouhal number. The peak PSD value for the shortest square cylinder (<em>h</em>/<em>w</em> = 3.5, <em>h</em>/<em>δ</em> = 1.1) was twice as high as that for the other cylinders; also, the high-pressure fluctuation area in this case did not spread downstream, which suggests that the flow from the top of the cylinder affected the Kármán vortex shedding generated from the cylinder’s sides. One contour of the two main modes extracted for the highest PSD via the right singular vector <strong>v_i</strong> at the Kármán vortex frequency had an asymmetric distribution behind the supported taller square cylinders (<em>h</em>/<em>w</em> ≥ 7.0, <em>h</em>/<em>δ</em> ≥ 2.3). This result is considered to be derived from the Kármán vortex shedding being mainly generated from the mainstream rather than the boundary-layer flow.</p></div>","PeriodicalId":12294,"journal":{"name":"Experimental Thermal and Fluid Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140785139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}