SAE International journal of advances and current practices in mobility最新文献

{"title":"Fuel Effects on Regulated and Unregulated Emissions from Three Light-Duty Euro 5 and Euro 6 Diesel Passenger Cars","authors":"R. Williams, R. Dauphin, J. Andersson, P. Ziman, J. Rogerson, H. Hamje","doi":"10.4271/2020-01-2147","DOIUrl":"https://doi.org/10.4271/2020-01-2147","url":null,"abstract":"Substantial advances in European road vehicle emissions have been achieved over the past 3 decades driven by strengthening revisions in emissions legislation and enabled by advances in fuel, vehicle engine and emissions control technologies. As both vehicle technology and emissions legislation in Europe continue to evolve, Concawe has conducted a study to examine the opportunities that fuels can provide to further reduce emissions from light-duty diesel passenger cars. Three European diesel cars spanning Euro 5, Euro 6b and Euro 6d-TEMP emissions certification levels have been tested over the cold-start WLTC (Worldwide harmonized Light-duty Test Cycle) with 6 fuels: an EN590-compliant B5 (petroleum diesel containing 5% biodiesel by volume), a bioderived paraffinic diesel, a 50:50 blend of the aforementioned fuels, a low density petroleum-derived B5, a B30 and the same B30 additized with a high dose of cetane number improver. Results have shown that low density fuels with high hydrogen to carbon (H/C) ratio are capable of delivering benefits in tank-to-wheels CO2 (carbon dioxide), CO (carbon monoxide), HC (hydrocarbons), other greenhouse gases and NOx (oxides of nitrogen), whereas no further benefits were measured in NH3 (ammonia) or in PN (particle number) at the low baseline levels produced by the vehicles. Compared to B5, B30 gave a significant increase in NOx at the tailpipe from the Euro 5 car and engine-out from the Euro 6d-TEMP car but no tailpipe detriments in NOx were measurable in either of the Euro 6 cars, due to the good performance of their NOx aftertreatment devices. The latter results show that some fuel qualities previously important to control emissions such as PN or NOx have become less impactful with the latest engine technologies. The addition of cetane number improver to the B30 did not reduce NOx. The findings suggest that high H/C ratio diesel fuels could offer benefits to both emissions affecting local air quality and to greenhouse gas emissions on a tank-to-wheels basis. The addition of higher FAME (Fatty Acid Methyl Ester) levels to fuels can be used to increase renewable fuel contribution resulting in no penalty in NOx emissions from newer technology vehicles. Compatibility of these fuels with the existing vehicle fleet would require further specific consideration. Introduction The EN590 specification [1] is used to control automotive diesel fuel quality in Europe to ensure the reliable operation of road vehicles. The current specification is the culmination of 3 decades of development driven by and enabling the introduction of sophisticated emissions aftertreatment devices such as DPFs (Diesel Particulate Filters (DPF) Lean NOx Traps (LNT) and Selective Catalytic Reduction catalysts (SCR) to achieve low emissions performance of the incumbent vehicles. Going forward, fuels used in diesel engines are likely to develop further and diversify to help meet future targets for CO2 (carbon dioxide) and other emissions associated","PeriodicalId":87358,"journal":{"name":"SAE International journal of advances and current practices in mobility","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84851265","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":"Research of Fuel Components to Expand Lean-limit in Super Lean-burn Condition (Part II)","authors":"Taketora Naiki, Ken Obata, Manabu Watanabe","doi":"10.4271/2020-01-2042","DOIUrl":"https://doi.org/10.4271/2020-01-2042","url":null,"abstract":"","PeriodicalId":87358,"journal":{"name":"SAE International journal of advances and current practices in mobility","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81767200","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":"Using Transmission Data to Isolate Individual Losses in Coastdown Road Load Coefficients.","authors":"Andrew Moskalik","doi":"10.4271/2020-01-1064","DOIUrl":"10.4271/2020-01-1064","url":null,"abstract":"<p><p>As part of the U.S. Environmental Protection Agency's (EPA's) continuing assessment of advanced light-duty automotive technologies in support of regulatory and compliance programs, the National Vehicle Fuels and Emissions Laboratory has benchmarked multiple transmissions to determine their efficiency during operation. The benchmarking included a modified \"coastdown test,\" which measures transmission output drag as a function of speed while in neutral. The transmission drag data can be represented as a second-order expression, like that used for vehicle coastdown test results, as <i>F</i> _<i>0</i> + <i>F</i> _<i>1</i> <i>V</i> + <i>F</i> _<i>2</i> <i>V</i> ², where <i>V</i> is the vehicle velocity. When represented in this fashion, the relationships among the three coefficients were found to be highly predictable. The magnitude of these coefficients can be quite large, and for some tested transmissions the deviation between the quadratic regression and the measured drag at individual velocities can be significant. To evaluate the effect of transmission losses in vehicle coastdown tests, the coastdown target and dynamometer set coefficients were pulled from the EPA's published \"Data on Cars used for Testing Fuel Economy\" for an entire model year. The same relationships seen among transmission coefficients were observed in the vehicle coefficients contained in these data. Therefore, the vehicle coefficients can be used directly to estimate the transmission and drivetrain losses and eliminate them from the coastdown values. With transmission losses eliminated, the remaining losses can be divided to extract more accurate estimations of aerodynamic losses and rolling losses. This process can be applied fleet-wide, using only the reported coastdown and dynamometer test coefficients to estimate the losses from individual sources. The resulting data can then be used to independently evaluate the effects of reducing each separate loss, without the need for detailed information on each vehicle in the fleet.</p>","PeriodicalId":87358,"journal":{"name":"SAE International journal of advances and current practices in mobility","volume":"2 4","pages":"2156-2171"},"PeriodicalIF":0.0,"publicationDate":"2020-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900940/pdf/nihms-1625134.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25408942","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":"High Efficiency by Miller Valve Timing and Stoichiometric Combustion for a Naturally Aspirated Single Cylinder Gas Engine","authors":"J. Judith, Denis Neher, M. Kettner, Danny Schwarz, M. Klaissle","doi":"10.4271/2019-32-0588","DOIUrl":"https://doi.org/10.4271/2019-32-0588","url":null,"abstract":"Small-scale cogeneration units (Pel < 50 kW) frequently use lean mixture and late ignition timing to comply with current NOx emission limits. Future tightened NOx limits might still be met by means of increased dilution, though both indicated and brake efficiency drop due to further retarded combustion phasing and reduced brake power. As an alternative, when changing the combustion process from lean burn to stoichiometric, a three-way-catalyst allows for a significant reduction of NOx emissions. Combustion timing can be advanced, resulting in enhanced heat release and thus increased engine efficiency.Based on this approach, this work presents the development of a stoichiometric combustion process for a small naturally aspirated single cylinder gas engine (Pel = 5.5 kW) originally operated with lean mixture. To ensure low NOx emissions, a three-way-catalyst is used. In order to achieve high engine efficiency, measures implemented include Miller valve timing, optimized intake system, reduced engine speed and increased compression ratio. In the first step, a detailed 1D engine cycle simulation model was used to investigate the efficiency benefit of Miller valve timing and increased compression ratio. Within the numerical study, inlet valve closing timing and intake pipe length were varied, yet a closed-loop control was implemented to maintain a constant effective compression ratio of 14.66 by adjusting geometrical compression ratio for each configuration. Subsequently, the most expedient valve timing was designed using multi-body simulation of the inlet valve train, while increased compression ratio was achieved by modifying the series piston bowl geometry.Engine trials agree with simulation results and show highest efficiency for a Miller valve timing closing +15 °CA later to the series valve timing and geometrical compression ratio of 15.36. Compared to the series lean burn engine, indicated and brake efficiency increase by 3.2 %-points to 39.0 % and by 3.9 %-points to 34.4 %, respectively, while maintaining original brake power of Pe = 6.1 kW. Finally, an experimental study accompanied by 3D-CFD simulations was conducted to investigate the potential of optimized piston geometry to further increase efficiency. However, results reveal only minor effect of piston geometry on efficiency, what is likely stemming from interrelation of combustion efficiency, wall heat losses and heat release rate.","PeriodicalId":87358,"journal":{"name":"SAE International journal of advances and current practices in mobility","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77983070","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":"Effects of Surface Compound Layer on Bending Fatigue Strength of Nitrided Chromium-Molybdenum Steel","authors":"T. Kubota, O. Umezawa","doi":"10.4271/2019-32-0504","DOIUrl":"https://doi.org/10.4271/2019-32-0504","url":null,"abstract":"<div class=\"section abstract\"><div class=\"htmlview paragraph\">Carburized and quenched materials with high fatigue strength are often used for motorcycle engine parts. Nitrided materials exhibit less deformation during heat treatment than carburized and quenched materials, so if the same or higher fatigue strength can be achieved with nitrided materials as with carburized and quenched materials, the geometric precision of parts can be increased and we can reduce engine noise as well as power loss. When the fatigue strengths of a nitrided material with its compound layer surface put into γ’ phase through nitriding potential control (hereafter, G), and a nitrided material put into ε phase (hereafter, E) were measured, the results showed the fatigue strength of the G to be about 11% higher than that of carburized and quenched materials. It was inferred that the strength of the compound layer determines fatigue strength. The reason the fatigue strength of the G is higher is that initial cracks do not readily form, and it can be inferred that when cracks do form, they progress readily and lead to final fracture. In the case of the E, it is thought that when the stress intensity factor, ΔK, due to initial cracks exceeds the threshold of the stress intensity factor range, ΔK_th (<span class=\"formula inline\"><math id=\"M1\" display=\"inline\"><mo>≃</mo><mn>5.9</mn><mi mathvariant=\"normal\">M</mi><mi mathvariant=\"normal\">P</mi><mi mathvariant=\"normal\">a</mi><msqrt><mi>m</mi></msqrt></math></span>), it leads to fatigue fractures. While the G has higher fatigue strength than carburized and quenched materials, it is likely to have a big effect on microcrack fatigue strength. This is a factor we believe requires consideration when designing engine parts for strength and in planning part manufacturing.</div></div>","PeriodicalId":87358,"journal":{"name":"SAE International journal of advances and current practices in mobility","volume":"2016 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86688322","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":"A Study of Ignition Method for Gas Heat Pump Engine Using Low Temperature Plasma","authors":"Y. Moriyoshi, O. Matsumoto, Tatsuya Kuboyama, T. Tsukamoto, Yoshiyuki Kinuzawa, Hideaki Maeshima","doi":"10.4271/2019-32-0622","DOIUrl":"https://doi.org/10.4271/2019-32-0622","url":null,"abstract":"Low temperature plasma ignition has been proposed as a new ignition technique as it has features of good wear resistance, low energy release and combustion enhancement. In the authors’ previous study, lean burn limit could be extended by low temperature plasma ignition while a voltage drop during discharge, leading to the transition to arc discharge, was found. In this study, the structure of plug and power supply’s performance with steep voltage rising with time, dV/dt, are examined to investigate the effects on combustion performance. As a result, comparing three power sources of conventional, IES and steep dV/dt, steep dV/dt showed small cycle-to-cycle variation and shorter combustion period, leading to higher peak value of the rate of heat release and better indicated thermal efficiency by relatively 6% and 4% compared to CIC and IES, respectively.","PeriodicalId":87358,"journal":{"name":"SAE International journal of advances and current practices in mobility","volume":"18 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72476427","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":"Combustion Characteristic of Offset Orifice Nozzle under Multi Pulse Ultrahigh Pressure Injection and PCCI Combustion Conditions","authors":"Pop-Paul Ewphun, Miku Otake, Tsuyoshi Nagasawa, H. Kosaka, Susumu Sato","doi":"10.4271/2019-32-0522","DOIUrl":"https://doi.org/10.4271/2019-32-0522","url":null,"abstract":"CI engines provide higher thermal efficiency compared to other internal combustion engines. On the other hand large amounts of smoke and NOx are produced during combustion. Smoke and NOx can be reduced by applying Premixed Charge Compression Ignition (PCCI) combustion. Unfortunately, the problems of PCCI combustion include unstable start of combustion and limited operating range. The multi-pulse ultrahigh pressure injection allows fuel to control PCCI combustion. The objective of offset orifice nozzle is to improve mixture formation and shorten spray penetration in order to increase thermal efficiency and control PCCI combustion. The offset orifice nozzle was designed by shift orifice aliment from into the sac center to edge of sac follow swirl direction. Counter bore design was applied to offset orifice nozzle in order to keep the constant orifice length as standard nozzle. This paper investigates the effect of nozzle orifice design on combustion characteristics under multi pulse ultra high pressure injection and PCCI combustion conditions. The experiments were carried out on a single cylinder engine at 0.55 MPa gross IMEP at 1,750 rpm. The injection pulses were 3 pulses equally mass main injection at 150, 200, 250, 300 and 350 MPa injection pressure. In case of standard nozzle orifice, 1st, 2nd pulse are PCCI followed by diffusive combustion in every injection pressure. For offset orifice nozzle orifice at 150 and 200 MPa 1st, 2nd pulse are also PCCI combustion. However when injection pressure is over 200 MPa, the 2nd pulse of rate of heat release become diffusive combustion. The offset orifice nozzle resulted in increased thermal efficiency, NOx and smoke. However significant differences between the smoke of offset orifice nozzle and standard nozzle were not found under injection pressure 300 and 350 MPa. The offset orifice nozzle also resulted in decrease CO and THC.","PeriodicalId":87358,"journal":{"name":"SAE International journal of advances and current practices in mobility","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83089141","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":"Estimating a Rider’s Compensatory Control Actions by Vehicle Dynamics Simulation to Evaluate Controllability Class in ISO 26262","authors":"Maki Kawakoshi, Takashi Kobayashi, M. Hasegawa","doi":"10.4271/2019-32-0537","DOIUrl":"https://doi.org/10.4271/2019-32-0537","url":null,"abstract":"Controllability is defined in ISO 26262 as a driver’s ability to avoid a specified harm caused by a malfunction of electrical and electronic systems installed in road vehicles. According to Annex C of Part 12 of ISO 26262, simulation is one of the techniques that the Controllability Classification Panel (CCP) can use to evaluate comprehensively the controllability class (C class) of motorcycles. With outputs of (i) an index for the success of harm avoidance and (ii) the magnitude of the rider’s compensatory control action required to avoid harm, the simulation is useful for evaluating the C class of the degrees of malfunction that cannot be implemented in practice for the sake of the test rider’s safety.To aim at supplying data that the CCP can use to judge the C class, we try to estimate the vehicle behavior and a rider’s compensatory control actions following a malfunction using vehicle dynamics simulations. The simulated scenario is the occurrence of unintended deceleration during cornering caused by a malfunction of the electronically controlled combined braking system. The parameter values supplied to the simulation model are set based on data obtained from actual riding tests that were performed. Using this model, we extrapolates the vehicle behaviors and the rider’s compensatory control actions under conditions that an actual riding test cannot be feasible. Moreover, the estimation results demonstrate the likely magnitude of the steering torque relative to the deceleration due to the malfunction as data that the CCP could use to evaluate the C class.","PeriodicalId":87358,"journal":{"name":"SAE International journal of advances and current practices in mobility","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90614270","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":"Intermittent Injection for a Two-Stroke Direct Injection Engine","authors":"F. Balduzzi, L. Romani, L. Bosi, G. Ferrara","doi":"10.4271/2019-32-0524","DOIUrl":"https://doi.org/10.4271/2019-32-0524","url":null,"abstract":"Cycle-to-cycle variation is one of the main factors for high fuel consumption and emissions of a two-stroke engine during the low-load and low-speed running. The increase of residual gas ratio due to the lower delivered amount of fresh scavenging air leads to a lower flame front speed and, therefore, to a slow combustion or even misfiring. The consequence is a very high level of unburnt hydrocarbons, since a large amount of fuel does not take part in the combustion process.The use of a direct injection system allows a more flexible management of the injection of fuel over subsequent engine cycles. Under a low-load condition, the low request in terms of brake mean effective pressure (BMEP) can be achieved by performing a load control based on an intermittent injection, thus reducing the need for intake throttling and avoiding the loss of fresh fuel resulting from cycles without combustion. In more detail, the supply of fuel to the combustion chamber can be skipped for one or more cycles, thus performing a number of consecutive scavenging cycles with only fresh air. As a result, the fresh air is less diluted by the residual gas and the combustion efficiency increases.This paper presents the results of a preliminary experimental activity on the use of an intermittent injection strategy with a Low Pressure Direct Injection (LPDI) system. In more detail, the effect of skipping one cycle - thus operating the two-stroke engine in a four-stroke-like mode - was investigated at part load conditions by considering four BMEP levels (i.e. from 1.0 bar to 2.5 bar). The benefits of such strategy were evaluated at the test bench and compared with the performance of the standard operation mode. In particular, the cycle-to-cycle variation was drastically reduced and the combustion misfire was avoided with the intermittent injection, thus leading to a strong reduction of both hydrocarbon emissions and brake specific fuel consumption.","PeriodicalId":87358,"journal":{"name":"SAE International journal of advances and current practices in mobility","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85118264","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":"Tumble Flow Enhancement Applied for Low-Load Condition of Engines by Utilizing Reverse Flow Phenomenon in Intake Port","authors":"Y. Nakamura, Yosuke Inoue, Makoto Fujikubo","doi":"10.4271/2019-32-0509","DOIUrl":"https://doi.org/10.4271/2019-32-0509","url":null,"abstract":"<div class=\"section abstract\"><div class=\"htmlview paragraph\">We established a technology that can enhance the tumble flow in the cylinder only in a partial load range of the engine without the need to use any intake path switching mechanisms.</div><div class=\"htmlview paragraph\">Firstly, we attempted to understand the basic phenomena of intake flow by using a CFD model, while using a butterfly throttle valve in a straight pipe. By doing this, we were able to observe the reverse flow of intake air that appears after the intake air has passed the throttle valve when the throttle valve opening is 30% or less. This reverse flow is generated mainly in the flow that has passed the trailing edge of the throttle valve. At both sides of the trailing edge opening, the flow is slowed down by diffusing. The flow is then pulled into the low-pressure zone created behind the throttle valve. In addition, a part of the reverse flow merges with the air flowing on the leading-edge side.</div><div class=\"htmlview paragraph\">Next, we confirmed that installing a flow separator behind the throttle valve that vertically divides the flow can successfully capture the reverse flow into one of the two flow paths. Furthermore, we confirmed that optimizing the separator position can capture most of the flow into one path, thereby gaining the required amount of flow that can generate tumble in the combustion chamber.</div><div class=\"htmlview paragraph\">By applying the above results to an actual engine, we validated the effect through a CFD flow analysis and also steady flow tests. As a result, we confirmed that this system can enhance tumble within a partial load range of the engine to a level that is equivalent to that obtained by a tumble port that has a flow path switching mechanism.</div></div>","PeriodicalId":87358,"journal":{"name":"SAE International journal of advances and current practices in mobility","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91163466","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}