International Journal of Thermophysics最新文献

{"title":"Thermophysical Properties of a High Density Carbon/Carbon Composite from Ambient to Ultra-high Temperatures","authors":"Marco Attia,&nbsp;Wyman Zhuang,&nbsp;Kilahney Murphy","doi":"10.1007/s10765-026-03756-0","DOIUrl":"10.1007/s10765-026-03756-0","url":null,"abstract":"<div><p>Carbon/Carbon (C/C) composites are currently the material of choice for use on advanced thermal protection systems for high speed flight vehicles due to their excellent thermophysical properties, high specific stiffness and strength in hypersonic flight operational environments. Understanding the ultra-high thermophysical properties of C/C is essential for design purposes, especially where limited data exists for the temperature range of interest. To address this need, the thermophysical and spectroscopic properties of a nominated high density C/C composite material were characterized. Properties such as specific heat, thermal diffusivity, thermal expansion and thermal conductivity for the material in all three material orientations (x, y, z) were investigated between ambient temperature to 2600 <span>(^circ )</span>C. X-ray diffraction (XRD) and Raman spectroscopy were conducted to inform the chemical structure of the C/C composite material and thus provide rationale for the measured thermophysical behaviour. The thermophysical assessment of the C/C composite is provided in two parts, the first set of thermal properties were determined for the material in its untreated state (no heat treatment), and the second set demonstrates the effect of heat treatment on the chemical structure and resulting thermal properties. The coefficient of thermal expansion (CTE), diffusivity and conductivity of the composite exhibit a distinctive shift in the material properties for the temperature range of 1300 <span>(^circ )</span>C to 1500 <span>(^circ )</span>C. Subsequent thermal analyses beyond that temperature range are markedly different and indicative of the thermophysical properties expected of a composite subjected to heat treatment. Analyses of the same specimens (pre- and post-heating) were also conducted using XRD and Raman microscopy in order to investigate the resultant variation in thermophysical properties as a result of repeated heat treatments. The findings were useful to assess the performances of the C/C composite in extremely high temperature conditions for the potential applications of hypersonic vehicle structure and components.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"47 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148009382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Study on the Thermodynamic Properties of Quaternary Ammonium Salts-Based Deep Eutectic Solvent + Acetonitrile Binary Systems","authors":"Ying Wei,&nbsp;Yandan Niu,&nbsp;Jian Wang,&nbsp;Yingying Zuo","doi":"10.1007/s10765-026-03780-0","DOIUrl":"10.1007/s10765-026-03780-0","url":null,"abstract":"<div><p>In this study, quaternary ammonium salts-based deep eutectic solvent (DESs) were used as the research object. The thermodynamic properties of the binary mixture formed by DESs and acetonitrile (ACN) were systematically studied. By characterizing fundamental physicochemical properties, this work establishes a foundational theoretical basis for the practical application of such DESs. In this work, the density, surface tension, and electrical conductivity of binary mixtures of tetramethylammonium chloride:formic acid ([TC:FA]+ACN), tetramethylammonium chloride:1,2-propanediol ([TC:PP]+ACN), and tetramethylammonium chloride:triethanolamine ([TC:TA]+ACN) were measured. The excess molar volume (<i>V</i>^E), molar surface Gibbs energy (<i>g</i>_s), and molar electrical conductivity (<i>Λ</i>_m) of all mixed systems were obtained using the measured experimental data. Through the quantitative analysis of derivative parameters such as excess molar volume, the interaction mechanism between DESs and ACN was clarified. According to the theoretical model of surface tension prediction, the correlation between the predicted value of the surface tension and the experimental value was verified. The conductor-like screening model for real solvents (COSMO-RS) was used to explore the specific interaction between all DESs and organic solvents. This basic research not only provides key basic physical data for the industrial application of DESs, but also provides an important theoretical basis for system design and process optimization in the fields of extraction separation and electrochemistry.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"47 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148009505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling Surface Tension of (R32+R1234yf), (R134a+R1234yf), (R32+R1234ze(E)), and (R134a+R1234ze (E)) Mixtures: The Effect of Equation of State and Influence Parameter on Estimations of the Density Linear and Non-linear Gradient Theory","authors":"Erfan Ahmadi,&nbsp;Shahin Khosharay,&nbsp;Ehsan Heidaryan","doi":"10.1007/s10765-026-03773-z","DOIUrl":"10.1007/s10765-026-03773-z","url":null,"abstract":"<div><p>The combinations of the linear and non-linear gradient theory with Cubic Plus Association (CPA) and Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT) equation of state (EoS) were used to estimate the surface tension of the (R32+R1234yf), (R134a+R1234yf), (R32+R1234ze(E)), and (R134a+R1234ze(E)) systems. Three EoSs of CPA, PC-SAFT, and PCP-SAFT, and two correlations of the influence parameters were applied to each binary mixture. The results of the present study showed that the application of hydrogen bonding in the CPA and dipole–dipole interactions in the PC-SAFT (PCP-SAFT) leads to precise calculations of the surface tension for the applied refrigerant mixtures. The lowest and highest average absolute deviation percentages for surface tension estimation were 2.28 and 19.48, respectively. The surface-layer density profiles showed that the density profiles of all components are linear across the interface, so the central hypothesis of the linear gradient theory is acceptable for the applied mixtures.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"47 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148009423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermophysical Characterization and Solidification Dynamics of Functionalized Graphene Nanoplatelet-Enhanced Phase Change Materials in Spherical Encapsulation","authors":"Anbalagan Sathishkumar,&nbsp;P. Sundaram,&nbsp;K. S. Vignesh,&nbsp;Sung Chul Kim","doi":"10.1007/s10765-026-03778-8","DOIUrl":"10.1007/s10765-026-03778-8","url":null,"abstract":"<div><p>This study investigates the influence of functionalized graphene nanoplatelets (F-GNP) on the thermo-physical performance of a water-based phase change material (PCM) in a spherical encapsulation system. The primary objective is to identify the optimal nanoparticle concentration that enhances solidification kinetics without the use of surfactants. Experiments were conducted at varying F-GNP concentrations (0.3, 0.6, 0.9, 1.2, and 1.5 wt%), and the phase change behavior was analyzed using radial temperature measurements, differential scanning calorimetry, and derived performance parameters. The results show a significant enhancement in thermal conductivity, increasing from 0.56 to 0.83 W/m K (48%) with increasing concentration. In addition, the solidification time is reduced by up to 38%, and the phase change acceleration factor increases notably up to 1.2 wt%. However, beyond this concentration, the improvement becomes marginal, indicating saturation due to particle interaction and clustering effects. The time lag parameter decreases by 2%, confirming improved radial heat transfer. However, the DSC-measured latent heat shows a moderate reduction of approximately 6–7%, while the latent heat retention ratio decreases to 0.88 at the highest nanoparticle concentration, indicating a limited compromise in energy storage capacity. The nanoparticle effectiveness factor decreases with concentration, highlighting diminishing returns at higher loadings. The results show that F-GNP can effectively enhance PCM performance without surfactants, with an optimal concentration of 1.2 wt % balancing heat transfer enhancement and energy storage efficiency.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"47 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148009418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing Heat Recovery Ventilator Efficiency with Heat Storage System by Using Phase Change Materials","authors":"Sungwoong Yang,&nbsp;Jihee Nam,&nbsp;Yongjun Choi,&nbsp;Yujin Kang,&nbsp;Sumin Kim","doi":"10.1007/s10765-026-03774-y","DOIUrl":"10.1007/s10765-026-03774-y","url":null,"abstract":"<div><p>Ventilation is crucial for maintaining comfortable and healthy indoor air quality. However, it inherently increases building energy loads by introducing unconditioned outdoor air. While heat recovery ventilators mitigate this energy loss, further enhancing their heat exchange efficiency remains a significant challenge. To address this issue, this study proposes a thermal energy storage duct utilizing phase change materials to precondition the airflow and alleviate the thermal load on the ventilation system. Large-scale environmental chamber experiments were conducted under strictly controlled parameters. The evaluations included summer conditions with an indoor temperature of 24 °C and an outdoor temperature of 35 °C, alongside winter conditions with an indoor temperature of 22 °C and an outdoor temperature of 2 °C. The study evaluated 4 kg of octadecane with a melting point of 28 °C for summer cooling and a material with a 20 °C melting point for winter heating. Results demonstrated that the endothermic phase transition in summer reduced the outdoor air temperature by an average of 1 °C for 235 min, which enhanced the overall heat exchange efficiency by 9.6 %. Under winter conditions, the exothermic heat release from the storage duct effectively preheated the incoming outdoor air by 2 °C for 150 min. This led to a 2 % improvement in heat exchange efficiency and a 0.2 K increase in the supply air temperature. Physically, these findings indicate that the substantial latent heat capacity of the phase change material acts as a thermal buffer. This mechanism delays transient temperature fluctuations and reduces the dry bulb temperature difference across the heat exchanger. Consequently, integrating these thermal storage ducts presents a highly effective passive strategy for diminishing building energy consumption caused by ventilation.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"47 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148009419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 the Thermal Property Evolution of EPDM During Ablation for Thermal Protection Applications","authors":"Wenbin Li,&nbsp;Liang Ji,&nbsp;Hu Zhang","doi":"10.1007/s10765-026-03772-0","DOIUrl":"10.1007/s10765-026-03772-0","url":null,"abstract":"<div><p>Ablative polymer materials are widely used in thermal protection applications because of their excellent elasticity, electrical insulation, gas tightness, and ablation resistance. Ethylene Propylene Diene Monomer (EPDM) is one of the most promising ablative polymers due to its unique ablation resistance and favorable thermomechanical properties. Accurate thermophysical data for EPDM are essential for the precise design of thermal protection structures. These properties are required for thermal-response and ablation modeling, as they directly affect performance prediction and the structural design of thermal protection systems. However, the thermophysical properties of EPDM under ablative conditions remain insufficiently characterized. Therefore, this study experimentally characterized the thermophysical properties of EPDM elastomer before and after ablation. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were adopted to characterize thermal degradation behavior and specific heat capacity of EPDM over 25–600 ℃. Thermal conductivity was measured by the 1D steady-state method for surface-ablated samples over 23–605 ℃ and the transient plane source (TPS) method for bulk-ablated samples over 27–483 ℃. The spectral emissivity of EPDM before and after ablation was determined using an energy-balance calibration method with a Fourier transform infrared spectrometer. The results indicate that EPDM undergoes significant degradation and ablation at elevated temperatures, accompanied by marked reductions in its thermophysical properties. The mechanisms underlying these changes were also discussed.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"47 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148008599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Surface-Tension Model for Non-Ideal Liquid Mixtures Based on the Butler Equation Coupled with a Cubic EoS","authors":"Ricardo Macías-Salinas,&nbsp;Daniela Méndez-Díaz,&nbsp;María Antonieta Zuñiga-Hinojosa","doi":"10.1007/s10765-026-03771-1","DOIUrl":"10.1007/s10765-026-03771-1","url":null,"abstract":"<div><p>We presently applied the Butler equation coupled with a cubic equation of state (CEoS) to accurately represent the surface tension of several representative binary liquid mixtures containing highly polar and associating substances (<i>e.g.</i>, methanol + water, ethanol + water, 1-propanol + water, 2-propanol + water, acetic acid + water, and toluene + methanol) over the entire composition range, at saturation pressure, and within a temperature range of 20–50 °C. The main thermodynamic quantities involved in the resulting Butler-based model, namely the fugacity coefficients in the bulk and surface liquid phases, were obtained using the Peng–Robinson-Stryjek-Vera CEoS which was combined with modern mixing rules of the Wong–Sandler type, enabling a proper description of the highly non-idealities exhibited by the binary mixtures considered in this study. The results obtained were generally satisfactory; however, we found out that the performance of the present modeling approach was highly dependent on the choice of the molar surface area of the pure species (<i>A</i>_<i>i</i>) within the Butler framework. Consequently, three diverse modeling scenarios were explored: (1) estimating <i>A</i>_<i>i</i> values using the Paquette correlation, thus making the present model fully predictive; (2) using the recommended <i>A</i>_<i>i</i> values as reported by Suarez et al., also yielding a fully predictive model; and (3) treating the <i>A</i>_<i>i</i> values as adjustable parameters within the present model.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"47 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147938448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization and Functionalization of Cone Calorimetric Parameters of Flame Retardant Polyethylene Nanoarchitectures for Multifunctional Applications","authors":"Anthony Chidi Ezika,&nbsp;Christopher Igwe Idumah,&nbsp;Williams Kehinde Kupolati,&nbsp;Emmanuel Rotimi Sadiku","doi":"10.1007/s10765-026-03757-z","DOIUrl":"10.1007/s10765-026-03757-z","url":null,"abstract":"<div><p>As a result of elevated inherent flammability of polyethylene (PE) matrices during fire condition and their increasing applications in heat and fire prone sectors, it has become imperative to alleviate and mitigate their inherently high flammability in order to enlarge their scope of applications. Herein, the cone calorimetric parameters of PE including rapid time to ignition (Tign), elevated smoke production rate (SPR), high peak heat release rate (PHRR), high total heat release rate (THR), low limiting oxygen index (LOI), rapid heat release rate (HRR), high carbon dioxide (CO₂) and carbon monoxide (CO) release rates, high fire growth index (FGI), and UL-94-V-0 status, and so on, are analyzed to ascertain the degree of flame retardancy achieved for expanded multifunctional applications due to the inclusion of nanoparticles (graphene and derivatives, carbon nanotubes and derivatives, nanoclay and derivatives, and so on) within the polymeric matrices. However, this work is limited to interpretation of cone calorimetric parameters relative to thermal and flame retardant properties. Therefore, this paper investigates the thermal and flame retardant (FR) calorimetric parameters of PE nanocomposites for multifunctional applications especially in segments where heat inhibition and flame retardancy are essential.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture><span>The alternative text for this image may have been generated using AI.</span></div></div></figure></div></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"47 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147938030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermophysical Properties of Niobium (1000–2700 K): Multi-stepwise Pulse-Heating Measurements with Consistency Validation via a Revised Emissivity–Resistivity Relation","authors":"Hiromichi Watanabe","doi":"10.1007/s10765-026-03765-z","DOIUrl":"10.1007/s10765-026-03765-z","url":null,"abstract":"<div><p>Thermophysical properties of niobium were measured from 1000 K to 2700 K using a multi-stepwise pulse-heating technique that enables quasi-static and dynamic evaluations within a single heating sequence. Electrical resistivity, hemispherical total emissivity, specific enthalpy, and isobaric heat capacity were obtained, and the difference between enthalpy values obtained from quasi-static and transient analyses served as an internal indicator of time-scale-dependent effects, especially near <span>({T}_{text{m}})</span>. To assess cross-property consistency, we re-derived a Schmidt–Eckert relation using Fresnel-based optical modeling with Planck-weighted hemispherical integration, providing a resistivity-derived emissivity reference over the present <span>(rho T)</span> range. The calorimetrically measured emissivity agrees with the Drude/Hagen–Rubens-based reference over 1400–2300 K, defining an intrinsically reliable window for emissivity-corrected heat capacity evaluation, while data up to 2700 K remain practically usable for engineering applications when their expanded combined uncertainties are considered. Within these validated limits, working enthalpy and heat capacity were obtained with expanded combined uncertainties (<i>k</i> = 2) of ~ 2.9 % and ~ 2.0 %, respectively. This combined strategy—time-scale analysis plus resistivity-based validation—strengthens confidence in pulse-heating thermophysical data and provides insight into near-<span>({T}_{text{m}})</span> behavior of refractory metals.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"47 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10765-026-03765-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147937946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Optimal Protocols for Minimizing Entropy Production in Finite-Time Stochastic Thermodynamics","authors":"Yaorui Shen,&nbsp;Baiping He,&nbsp;Hao Zhu,&nbsp;Chao Li,&nbsp;Jianqin Fu","doi":"10.1007/s10765-026-03768-w","DOIUrl":"10.1007/s10765-026-03768-w","url":null,"abstract":"<div><p>Minimizing energy dissipation in finite-time operations and non-equilibrium steady states (NESS) remains a paramount challenge for micro- and nano-scale devices. This study systematically investigates the mechanisms of entropy production in Langevin systems and proposes a comprehensive theoretical framework for dissipation optimization. Through analytical and numerical solutions of the Langevin and Fokker–Planck equations, we first reveal a non-monotonic “unimodal” evolution of the non-adiabatic entropy production rate under finite-time driving (varying temperature, stiffness, and non-conservative forces), driven by the competition between external modulation and intrinsic relaxation. Furthermore, by utilizing a dual-coupled Brownian oscillator model, we elucidate how temperature gradients, coupling strength, and friction asymmetry modulate continuous adiabatic energy dissipation in NESS. To overcome the dissipation bottleneck, we systematically develop and compare three optimal control strategies: (1) geodesic protocols derived via thermodynamic geometry in the linear response regime; (2) exact optimal protocols derived via the calculus of variations which is capable of addressing arbitrary driving durations; and (3) auxiliary potential protocols within the Shortcuts to Isothermality (STI) framework designed to counteract far-from-equilibrium effects during rapid driving. Numerical simulations confirm that these advanced protocols significantly outperform conventional linear driving, with the STI method reducing total entropy production by up to 57% in fast-driving regimes. This work bridges the gap between transient evolution and steady-state transport, offering robust theoretical guidelines for designing high-efficiency and low-dissipation nanomachines.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"47 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147937948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}