Symposium (International) on Combustion最新文献

{"title":"Calibration and comparison of laser-induced incandescence with cavity ring-down","authors":"Randall L. Vander Wal","doi":"10.1016/S0082-0784(98)80390-1","DOIUrl":"10.1016/S0082-0784(98)80390-1","url":null,"abstract":"<div><p>Laser-induced incandescence (LII), a technique that determines relative soot volume fraction, requires calibration to achieve quantitative results. Although not spatially resolved, cavity ring-down (CRD), an absorption-based method, provides an integreated meausre of <em>f</em>_v along the line-of-sight. Here, spatially resolved LII signals from soot within a methane/air diffusion flame are calibrated using CRD, which avoids extrapolation required of less sensitive methods in current use. Comparison of CRD with traditional light extinction and path-integrated LII verifies its accuracy for <em>f</em>_v determination. Using CRD, quantification of LII for parts per billion (ppb) <em>f</em>_v levels is demonstrated. Experimental tests demonstrate the accuracy of CRD for a single laser-pulse to be better than ±5% for measurement of ppb soot volume fraction levels over a 1-cm pathlength. Using calibrated detector characteristics and a predetermined <em>f</em>_v level, the absolute LII signal level within a detection bandwidth of 405–415 nm produced by a laser fluence of 0.25 J/cm² at 1064 nm within a laminar ethylene/air diffusion flame was calculated. This value is 5×10⁵ photons/srnm per ppm of soot, collected over a 10-ns interval centered at the peak of the LII signal. Comparison of LII with CRD reveals that CRD may be used to advantage in applications where spatially resolved information is not necessary and/or achieving high geometric collection efficiency is impractical LII's chief advantages are the spatially resolved <em>f</em>_v visualization and geometric versatility.</p></div>","PeriodicalId":101203,"journal":{"name":"Symposium (International) on Combustion","volume":"27 1","pages":"Pages 59-67"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0082-0784(98)80390-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"104946460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurements of formaldehyde concentrations and formation rates in a methane-air, non-premixed flame and their implications for heat-release rate","authors":"Michael P. Tolocka,&nbsp;J. Houston Miller","doi":"10.1016/S0082-0784(98)80455-4","DOIUrl":"10.1016/S0082-0784(98)80455-4","url":null,"abstract":"<div><p>Tunable diode laser absorption spectroscopy coupled with microprobe sampling was used to quantitatively determine formaldehyde concentrations in a methane-air non-premixed flame. Resulting concentration profiles are similar in shape and peak locations to previous qualitative measurements, and concentration levels are in line with those predicted by direct numerical simulation of methane-air flames. The resulting concentrations were combined with other data from this flame system in a mixture fraction-based code to predict levels for species whose concentrations are not available experimentally. An analysis was performed of formaldehyde formation and destruction paths to determine HCHO's dependence on specific reaction steps. Formaldehyde formation is dominated by the reaction between methyl radical and oxygen atom, and it is destroyed by hydrogen abstraction. Both processes occur near the stoichiometric surface. The analysis also verified several points made by other researchers about the heat-release rates in methane flames. Heat-release rate correlates well with the destruction rate of methane, the rate of the reaction between methyl radicals and oxygen atoms, and HCO concentrations. A condition of chemical steady state is found for HCO, and the steady-state estimate of HCO concentration may also be used to estimate local heat-release rate in methane flames.</p></div>","PeriodicalId":101203,"journal":{"name":"Symposium (International) on Combustion","volume":"27 1","pages":"Pages 633-640"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0082-0784(98)80455-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"108302325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interaction of a vortex with a flat flame formed between opposing jets of hydrogen and air","authors":"V.R. Katta ,&nbsp;C.D. Carter ,&nbsp;G.J. Fiechtner ,&nbsp;W.M. Roquemore ,&nbsp;J.R. Gord ,&nbsp;J.C. Rolon","doi":"10.1016/S0082-0784(98)80450-5","DOIUrl":"10.1016/S0082-0784(98)80450-5","url":null,"abstract":"<div><p>Studies on individual vortex-flame interactions constitute important elements for the understanding of the turbulent-flame structure. Vortices having sufficiently high normal velocity can pass through the flame by extinguishing it locally. In several circumstances they deform the flame surface significantly before attaining extinction conditions. The development of curvature on the flame surface, especially in hydrogen flames, could lead to different quenching patterns. An experimental/numerical investigation is performed to explore possible quenching patterns in opposing-jet diffusion flames. A diluted hydrogen-nitrogen mixture is used as the fuel. Vortices are driven toward the flame surface with different velocities from the air side. The changes in the structure of the flame during its interaction with the incoming vortex are recorded by measuring instantaneous OH-concentration field using the laser-induced fluorescence (LIF) technique. A time-dependent CFDC code that incorporates 13 species and 74 reactions is used for the simulation of these vortex-flame interactions. Both the experiments and calculations have identified two types of quenching patterns: namely, point and annular. It is found that when an air-side vortex is forced toward the flame at a relatively high speed, then the flame at the stagnation line quenches, resulting in a well-known point-quenching pattern. On the other hand, when the vortex is forced at a moderate speed, the flame surface deforms significantly, and quenching develops in an annular ring away from the stagnation line, resulting in an unusual annular-quenching pattern. Detailed analyses performed just before the development of annular quenching and 1 ms later suggest that this unusual annular quenching did not result from the strain rate. Based on the understanding gained from previous investigations on curvature effects in coaxial hydrogen jet flames and the findings made in the present study, it is argued that such quenching develops as a result of the combined effect of preferential diffusion and flame curvature.</p></div>","PeriodicalId":101203,"journal":{"name":"Symposium (International) on Combustion","volume":"27 1","pages":"Pages 587-594"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0082-0784(98)80450-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"95166718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The transformation of chromium in a laminar premixed hydrogen-air flame","authors":"Suyuan Yu ,&nbsp;A. Daniel Jones ,&nbsp;Daniel P.Y. Chang ,&nbsp;Peter B. Kelly ,&nbsp;Ian M. Kennedy","doi":"10.1016/S0082-0784(98)80002-7","DOIUrl":"https://doi.org/10.1016/S0082-0784(98)80002-7","url":null,"abstract":"<div><p>The transformation of chromium was studied numerically and experimentally in a simple laminar premixed hydrogen-air flame. Chromium was added to the flame as a vapor of chromium hexacarbonyl that provided a source of zero-oxidation-state pure elemental chromium through its rapid pyrolysis. The flame was operated over a range of equivalence ratios. The metal aerosol and vapors that were created in the flame were sampled at different heights with a dilution sampling probe. Aerosol was collected on a filter and vapors in a liquid nitrogen trap. Analysis of the samples showed an initial increase in the amount of hexavalent chromium with increasing distance from the burner, followed by a drop to about 5% far from the burner. The modeling of detailed chromium kinetics showed a similar behavior. The observations highlighted the importance of finite-rate kinetics in controlling the ultimate state of the metal oxide. Aerosol samples were analyzed with an electrical mobility analyzer and condensation nuclei counter. Mean diameters were of the order of 40 nm. The numerical model of the chromium aerosol showed qualitatively good agreement between measured and predicted aerosol size distributions.</p></div>","PeriodicalId":101203,"journal":{"name":"Symposium (International) on Combustion","volume":"27 2","pages":"Pages 1639-1645"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0082-0784(98)80002-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72292790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fullerenes and PAH in low-pressure premixed benzene/oxygen flames","authors":"William J. Grieco ,&nbsp;Arthur L. Lafleur ,&nbsp;Kathleen C. Swallow ,&nbsp;Henning Richter ,&nbsp;Koli Taghizadeh ,&nbsp;Jack B. Howard","doi":"10.1016/S0082-0784(98)80006-4","DOIUrl":"https://doi.org/10.1016/S0082-0784(98)80006-4","url":null,"abstract":"<div><p>The formation of fullerenes is though to be a molecular weight growth process similar to the formation of polycyclic aromatic hydrocarbon (PAH) and soot in flames, although little is known about the specific mechanisms involved. The goal of this study is to investigate possible fullerences formation pathways. This work measures for the First time concentration profiles of fullerences C₆₀, C₇₀, C₇₆, C₇₈, and C₈₄, PAHs (up to 300 amu), and unidentified PAHs in the mass range between PAHs and soot in a heavily fullerene-forming premixed benzene/oxygen flame operated at the following conditions: fuel equivalence ratio, 2.4 (atomic C/O ratio, 0.96): cold gas velocity, 25 cm/s: pressure, 5.33 kPa: and fraction of argon in fuel mixture, 10 mol%. Two regions of fullerenes formation are identified in this flame. The First formation region occurs early in the flame simultaneously with PAH consumption. The rate of PAH consumption is more than large enough to account for the obsered rate of fullerenes formation, so this formation region may involve reactions of PAH. The Second region, which accounts for most of the fullerenes mass produced in the flame, occurs later in the flame and is more consistent with stepwise acetylene addtion to fullerene precursors. In both regions, fullerenes consumption that may involve reactions between fullerenes and soot is observed. In addition, measurements indicate that the different PAHs grow roughly simultaneously, reach a peak concentration, and decay together in a consumption process that occurs at the same time as a rapid rise in soot mass concentration early in the flame. This behavior is consistent with the major soot formation being from PAH and occurring along with the minor fullerenes formation in this flame.</p></div>","PeriodicalId":101203,"journal":{"name":"Symposium (International) on Combustion","volume":"27 2","pages":"Pages 1669-1675"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0082-0784(98)80006-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72292792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The formation of nitrogen species and oxygenated PAH during the combustion of coal volatiles","authors":"Elmer B. Ledesma ,&nbsp;Peter F. Nelson ,&nbsp;John C. Mackie","doi":"10.1016/S0082-0784(98)80008-8","DOIUrl":"https://doi.org/10.1016/S0082-0784(98)80008-8","url":null,"abstract":"<div><p>The combustion of coal volatiles produced by rapid pyrolysis was studied using a two-stage reactor consisting of a fluidized-bed reactor coupled to a tubular-flow reactor. Volatiles were generated in the fluidized-bed reactor under high heating rates and at 600°C such that the major volatile species produced were tars. The freshly generated tars were subsequently oxidized in the tubular-flow reactor at 900 and 1000°C. Fourier transform infrared (FTIR) analysis showed that, with an increase in oxygen concentration, the recovered tars exhibited and increased in the carbonyl, C=O, functionality. The position of the C=O peak and the presence of absorbances in the aromatic C−H out-of-plane deformation region in the FTIR spectra and GC/MS identification demonstrate that polycyclic aromatic ketones and aldehydes are significant oxygenated polycyclic aromatic hydrocarbons (OPAH) products from coal volatiles combustion. The results indicate that combustion processes are primarily responsible for OPAH formation. HNCO yield was found to increase rapidly with the addition of small amounts of oxygen. The results show that HCN oxidation is not primarily responsible for HNCO formation: reactions of other N-containing species are likely sources. The observation of HNCO suggests that previous measurements of NH₃ in coal combustion probably represent the sum of NH₃ and HNCO yields. The presence of hydrocarbon species (gases and tars) has a significant effect on fuel-N conversion. The experimental results clearly demonstrated that NO production increased significantly onee the concentration of hydrocarbons decreased.</p></div>","PeriodicalId":101203,"journal":{"name":"Symposium (International) on Combustion","volume":"27 2","pages":"Pages 1687-1693"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0082-0784(98)80008-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72292793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radical concentration profiles in a low-pressure methane-air flame measured by intracavity laser absorption and cavity ring-down spectroscopy","authors":"Vladimir A. Lozovsky ,&nbsp;Igor Derzy ,&nbsp;Sergey Cheskis","doi":"10.1016/S0082-0784(98)80433-5","DOIUrl":"10.1016/S0082-0784(98)80433-5","url":null,"abstract":"<div><p>Intracavity laser absorption spectroscopy (ICLAS) and cavity ring-down spectroscopy (CRDS) were used to measure temperature and concentration profiles in low-pressure (30 torr) methane/oxygen/nitrogen flames. Concentration profiles of the HCO and ¹CH₂ radicals were measured by ICLAS, whereas the OH radical profiles and temperature profiles were measured by CRDS. Flames with equivalence ratio =0.8, 1.0, and 1.2 were studied. HCO profiles and peak amounts agree well with model predictions based on the GRI-Mech 2.11 mechanism for the stoichiometric flame (=1.0). The absolute concentration of singlet CH₂ radical could not be determined accurately, because of large uncertainty in the absorption cross section of this radical. Nevertheless, the experimental singlet CH₂ concentration seems to be higher than predicted by model (by more than 20 times, based on the estimated cross-section data). The relative ¹CH₂ profile is very close to the prediction. The OH profiles agree well with model calculation: however, absolute experimental OH peak concentration is about two times lower than the predicted value.</p></div>","PeriodicalId":101203,"journal":{"name":"Symposium (International) on Combustion","volume":"27 1","pages":"Pages 445-452"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0082-0784(98)80433-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"96646429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effects of pressure, temperature, and concentration on the reactivity of alkanes: Experiments and modeling in a rapid compression machine","authors":"C.K. Westbrook ,&nbsp;H.J. Curran ,&nbsp;W.J. Pitz ,&nbsp;J.F. Griffiths ,&nbsp;C. Mohamed ,&nbsp;S.K. Wo","doi":"10.1016/S0082-0784(98)80425-6","DOIUrl":"10.1016/S0082-0784(98)80425-6","url":null,"abstract":"<div><p>Experiments in a rapid compression machine have examined the influences of variations in pressure, temperature, and equivalence ratio on the autoignition of <em>n</em>-pentane. Equivalence ratios included values from 0.5 to 2.0, compressed gas initial temperatures were varied between 675 and 980 K, and compressed gas initial pressures varied from 8 to 20 bar. Numerical simulations of the same experiments were carried out using a detailed chemical kinetic reaction mechanism. The results are interpreted in terms of a lowtemperature oxidation mechanism involving addition of molecular oxygen to alkyl and hydroperoxyalkyl radicals. Idealized calculations are also reported that identify the major reaction paths at each temperature. Results indicate that in most cases, the reactive gases experience a two-stage autoignition. The first stage follows a low-temperature alkylperoxy radical isomerization pathway that is effectively quenched when the temperature reaches a level where dissociation reactions of alkylperoxy and hydroperoxyalkylperoxy radicals are more rapid than the reverse addition steps. The second stage is controlled by the onset of dissociation of hydrogen peroxide. Results also show that in some cases, the first-stage ignition takes place during the compression stroke in the rapid compression machine, making the interpretation of the experiments some-what more complex than commonly assumed. At the highest compression temperatures achieved, little or no first-stage ignition is observed.</p></div>","PeriodicalId":101203,"journal":{"name":"Symposium (International) on Combustion","volume":"27 1","pages":"Pages 371-378"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0082-0784(98)80425-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"105730202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational and experimental study of ammonium perchlorate combustion in a counterflow geometry","authors":"Michael A. Tanoff ,&nbsp;Nenad Ilincic ,&nbsp;Mitchell D. Smooke ,&nbsp;Richard A. Yetter ,&nbsp;Timothy P. Parr ,&nbsp;Donna M. Hanson-Parr","doi":"10.1016/S0082-0784(98)80091-X","DOIUrl":"10.1016/S0082-0784(98)80091-X","url":null,"abstract":"<div><p>We investigate the structure of ammonium perchlorate (AP) counterflow diffusion flames in which the products of AP combustion are counterflowed against a methane fuel stream. Computationally, the two dimensional set of governing equations is reduced to a one-dimensional bouandary value problem along the stagnation point streamline through the introduction of a similarity transformation. Utilizing recent developments in hydrocarbon, chlorine, NO_<em>x</em>, N_<em>x</em>, H_<em>y</em>, and AP kinetics, we formulate a detailed transport, finite-rate chemistry system for the temperature, velocity, and species mass fractions of the combined flame system. We compare the results of this model with a series of experimental measurements in which the temperature is measured with radiation-corrected thermocouples and the OH rotational population distribution, and several important chemical species, including OH, CN, NH, NO, CH₄, and O₂ are measured with planar laser-induced fluorescence (PLIF), emission spectroscopy, and Raman spectroscopy.</p><p>Both the model and the measurements reveal a multistage structure within the counterflow system comprised of an AP decomposition flame (above the AP surface) folowed by a methane AP-products diffusion flame. The calculated temperature profile is predicted to be in excellent agreement with the OH rotational temperature measurements. Measured peak CN concentrations match the spatial location predicted by the model exactly. The kinetic mechanism is able to resolve the two experimentally oberved NH peaks, one very close to the AP surface, near their proper relative intensities, Quatitative OH concentration measurements are in very good agreement with the corresponding calculated profile, matching in spatial location, and differeing by 17% in peak value. Quatitative NO measurements match the corresponding calculation, with both revealing a two-tiered structure. Low number densities and spectral broad ening at high temperatures result in poorer agreement between the Raman measurements and the corresponding major species calculations, although fuel methane and AP-generated oxygen consumption are measured with reasonable agreement.</p></div>","PeriodicalId":101203,"journal":{"name":"Symposium (International) on Combustion","volume":"27 2","pages":"Pages 2397-2404"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0082-0784(98)80091-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"104464647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature and mixture fraction measurements in gases by laser-induced electrostrictive gratings","authors":"B. Hemmerling,&nbsp;W. Hubschmid,&nbsp;A. Stampanoni-Panariello","doi":"10.1016/S0082-0784(98)80391-3","DOIUrl":"10.1016/S0082-0784(98)80391-3","url":null,"abstract":"<div><p>We applied time-resolved light scattering from electrostrictive gratings to measure nonintrusively gas compositions and temperatures. The infrared radiation of a pulsed Nd:YAG laser generates a spatially periodic density grating that oscillates in time, and the beam of a cw laser is used to read it out. The oscillation period of the signal depends on the sound velocity in the medium. If the gas composition is known, the measurement of the sound velocity allows the temperature to be deduced. We evaluated this novel technique in a tube furnace for temperatures in air up to about 1400 K. Although the measured temperatures agree within the error bars with the thermocouple readings, there is some evidence that the temperatures determined by the laser-induced grating technique are systematically too high. For singleshot temperature measurements in air, we determined a statistical error of 70 K at a furnace temperature of 1400 K.</p><p>On the other hand, if the temperature is known, concentrations in isothermal binary mixtures can be determined by the laser-induced grating technique. We performed measurements in methane-nitrogen and hydrogen-nitrogen mixtures. The limits for the minimum detectable variation of the gas composition of 0.5 mole fraction mixtures were found to be 2% and 0.6%, respectively. One advantage of the proposed method is the simple evaluation process that allows for on-line measurements of temperature or gas compositions.</p></div>","PeriodicalId":101203,"journal":{"name":"Symposium (International) on Combustion","volume":"27 1","pages":"Pages 69-75"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0082-0784(98)80391-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"98127158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}