Ming Wang , Wentao Wang , Leilei Han , Jiajun Chen , Yu Chen , Yun Wu , Yong Zhao
{"title":"Effect of sintering time on the characteristics of YBCO coated-conductor joints using nano-silver paste","authors":"Ming Wang , Wentao Wang , Leilei Han , Jiajun Chen , Yu Chen , Yun Wu , Yong Zhao","doi":"10.1016/j.physc.2024.1354485","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354485","url":null,"abstract":"<div><p>Jointing YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-z</sub> (YBCO) superconducting coated-conductor (CC) tapes is becoming increasingly significant for magnet applications because of the limited length of single tapes. In this work, YBCO CC tapes stabilized by silver were connected by low-temperature sintering of nano-silver paste. The effect of sintering time and lapped length on the electrical properties of YBCO joints were systematically investigated. And the correlation between microstructure and bonding force of the joints with extending the sintering time was established. It is found that joints sintered within 1∼5 min exhibit relatively lower resistance, while the maximum axial tensile strength at room temperature (RT) was improved with increasing sintering time. Considering the electromechanical properties, ten min is selected as the optimal sintering time for nano-silver paste. The joint by this efficient technology possesses closely connected interface, similar critical current and axial tensile strength (RT) to the single CC tape. The joint resistivity is as low as ∼12.5 nΩ·cm<sup>2</sup>, which is much less than the traditional soldering joint.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"620 ","pages":"Article 1354485"},"PeriodicalIF":1.7,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140818258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mechanical behavior of multi-layer CORC cable in high external field with 3D numerical model","authors":"Shouhong Shan , Huadong Yong , Youhe Zhou","doi":"10.1016/j.physc.2024.1354501","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354501","url":null,"abstract":"<div><p>The degradation of critical current due to mechanical deformation in a high field has a profound impact on the performance of high-temperature superconducting (HTS) structures. The multi-layer conductor on round core (CORC) cable is a widely-applied HTS structure in engineering. Due to the complexity of the multi-layer CORC cable, the contact between the tapes should be considered when simulating the mechanical behavior in high field. In this paper, 3D electromagnetic and mechanical models were developed to investigate the mechanical behavior of the multi-layer CORC cable. Under the same electromagnetic force, the comparisons of mechanical models of a 5-layer CORC cable with different contact methods are presented. Subsequently, the effects of the loading path of the external magnetic field and transport current, the bending geometry of the CORC cable, the winding direction of the HTS tape in the CORC cable, and the shielding current on the mechanical behavior are discussed, respectively. The numerical results are useful for the design and operation of CORC cable in high field.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"620 ","pages":"Article 1354501"},"PeriodicalIF":1.7,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140818256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Enhanced conductivity in Sr doped La3Ni2O7-δ with high-pressure oxygen annealing","authors":"Keke Jiao , Rui Niu , Huixin Xu , Weili Zhen , Jingrong Wang , Changjin Zhang","doi":"10.1016/j.physc.2024.1354504","DOIUrl":"10.1016/j.physc.2024.1354504","url":null,"abstract":"<div><p>The structural, electrical and magnetic properties of a series of La<sub>3-x</sub>Sr<sub>x</sub>Ni<sub>2</sub>O<sub>7-δ</sub> polycrystalline samples have been systematically investigated with and without high-pressure oxygen annealing. Without annealing, the introduction of Sr at La site leads to a moderate enhancement of conductivity. The high-pressure oxygen annealing leads to an increase of oxygen content by ∼1.08 %. Consequently, the conductivity of the annealing samples is significantly enhanced comparing to the untreated samples. The La<sub>3-x</sub>Sr<sub>x</sub>Ni<sub>2</sub>O<sub>7-δ</sub> samples exhibit metal-like behavior in the whole temperature range with annealing, which is due to the hole doping effect. The present results could contribute to the exploration of possible ambient superconductivity in La<sub>3</sub>Ni<sub>2</sub>O<sub>7-δ</sub> system.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"621 ","pages":"Article 1354504"},"PeriodicalIF":1.7,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140766172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Thermomagnetic instability in superconducting lead-porous glass nanocomposites","authors":"A.E. Shitov, N.Yu. Mikhailin, Yu.A. Kumzerov, D.V. Shamshur","doi":"10.1016/j.physc.2024.1354502","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354502","url":null,"abstract":"<div><p>In this paper we examine the mechanisms leading to thermomagnetic instability in nanostructured materials and study their regularities. The appearance of thermomagnetic instabilities in the superconducting state of various materials remains one of the problems of applications of superconductors. We studied the temperature and the magnetic field dependences of the magnetization <em>m(T, H)</em> and heat capacity <em>C(T, H)</em> of a nanocomposite consisting of interconnected lead filaments embedded in nanoporous glass (Pb-PG) with filament diameter <em>d</em> = 7 nm. Porous glass contains an arbitrarily orientated multiply connected system of pores of approximately the same size; lead in the nanocomposite forms a replica of the pore system. Thermomagnetic instability was previously observed in this material in superconducting state at <em>T</em> ≤ 5 K on <em>m(H)</em> dependencies in magnetization studies. We established that high enough external heater power <em>P</em> used during the heat capacity measurements in external magnetic field <em>C(H)</em> at <em>T</em> ≤ 5 K can initiate thermomagnetic instability and penetration of magnetic flux into the nanocomposite. The thermomagnetic instability is generally preceded by a sequence of small heat release events with the same magnitude as <em>P</em>. Another sequence of small heat release events is observed in the region close to <em>H<sub>c2</sub></em>. These events are presumably linked to the thermomagnetic instability process and are caused by small redistribution of magnetic flux in the nanocomposite.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"620 ","pages":"Article 1354502"},"PeriodicalIF":1.7,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140551514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Further analysis of flux trapping experiments on hydrides under high pressure","authors":"J.E. Hirsch , F. Marsiglio","doi":"10.1016/j.physc.2024.1354500","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354500","url":null,"abstract":"<div><p>It has been claimed that measurements of trapped magnetic flux in hydrides under pressure provide evidence for superconductivity in these materials (Minkov et al., 2022; Minkov et al., 2023). In recent work we have questioned that claim (Hirsch and Marsiglio, 2022). Here we point out that recent experiments (Bud’ko et al., 2023) provide further evidence supporting our questioning of that claim. We also present calculations for a thin disk and compare these with those previously calculated for a long cylinder. The results are qualitatively similar, and therefore reinforce our previous conclusions. We also address recent criticism of our paper Ref. (Hirsch and Marsiglio, 2022) by Bud’ko (2024) and by Talantsev et al. (2023).</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"620 ","pages":"Article 1354500"},"PeriodicalIF":1.7,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0921453424000650/pdfft?md5=b2c54c099faa009bb8165100e557c207&pid=1-s2.0-S0921453424000650-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140552373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sara Zoveydavi , Mehdi Hosseini , Zahra Owjifard , Ali Moftakharzadeh
{"title":"Investigation of the effect of conformal pinning array on critical current density in infinitely long superconductors","authors":"Sara Zoveydavi , Mehdi Hosseini , Zahra Owjifard , Ali Moftakharzadeh","doi":"10.1016/j.physc.2024.1354498","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354498","url":null,"abstract":"<div><p>In this study, the influence of conformal pinning centers on enhancing the critical current density in superconductors has been investigated. To increase the critical current density, a square-pinned array with dimensions of 10λ by 10λ under two appropriate conformal transformations is considered. Initially, by specifying the forces acting on the vortices, the relevant Langevin equation for the vortices is solved. By solving this equation, the vortex positions versus time are determined, and using this information, the critical current density is calculated as a function of the magnetic field. Then, the critical current density is calculated for various conformal function parameters in a superconductor tape. The results indicate that after applying two conformal transformations with appropriate parameters, the critical current density could be increased at higher magnetic fields. Simulations demonstrate a 25% increase in critical current density in the optimal case.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"620 ","pages":"Article 1354498"},"PeriodicalIF":1.7,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140535168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhidan Zhang, Xuesong Feng, Wenqi Wu, Hai Wang, Xiangyan Kong
{"title":"Magnetic field-to-voltage coefficient evaluation of axial SQUID gradiometer in unshielded environment","authors":"Zhidan Zhang, Xuesong Feng, Wenqi Wu, Hai Wang, Xiangyan Kong","doi":"10.1016/j.physc.2024.1354468","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354468","url":null,"abstract":"<div><p>Due to the existence of earth magnetic field, it is difficult to detect weak magnetic field from some parts of the body like heart, muscle, nerve and so on. In addition to the requirement for high-sensitivity magnetic field sensors, it is also essential to take certain measures to suppress noise. The axial gradiometer based on low-Tc Superconducting QUantum Interference Device (SQUID) can achieve a noise suppression ratio of 30 dB through the spatial gradient difference of the magnetic field, but the calibration of the magnetic field-to-voltage coefficient (B-V coefficient) generally requires a magnetically shielded room (MSR), which is complex and costly. With finite element simulation and practical experiments, a calibration method for B-V coefficient of the axial hardware gradiometer without shielding was presented in this paper. That is, a larger calibration field was generated for coefficient evaluation in an unshielded environment. At the same time, when the test signal was far away, the spatial gradient difference was used to improve the authenticity of the evaluation results. Through simulation and experimental verification, for the same performance and configuration of the gradiometer, the calibration result was 1.6 nT/V with 0.1 nT/V difference from that in a shielding room. The results showed that the unshielded evaluation method proposed in this paper was practical and could be used to evaluate the B-V coefficient of gradiometer.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"619 ","pages":"Article 1354468"},"PeriodicalIF":1.7,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140309326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kangshuai Wang , Yong Chen , Qiuliang Wang , Quanyue Liu , Lei Wang , Jianhua Liu
{"title":"Electromagnetic and Thermal analysis of an Intra-layer no-insulation coil during Quench","authors":"Kangshuai Wang , Yong Chen , Qiuliang Wang , Quanyue Liu , Lei Wang , Jianhua Liu","doi":"10.1016/j.physc.2024.1354477","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354477","url":null,"abstract":"<div><p>The intra-layer no-insulation (LNI) layer-wound REBCO coil has been widely studied for its excellent high thermal stability in the research of nuclear magnetic resonance superconducting magnets. Due to the complex structure of the LNI layer-wound coil and the numerous factors that affect thermal stability, its quench characteristics are not clear. In this paper, a numerical multiphysics coupling model is established to study the transient electromagnetic and thermal behaviors of the LNI layer-wound coil during quench. The results indicate that temperature follows the diffusion law, while the currents evolve through electrical connection and electromagnetic induction. Due to the high contact resistance, the azimuthal current and axial current vary almost in units of the entire coil layer. The direction of the radial current upstream of the turn where a quench occurs is positive due to the bypassing behavior, while the radial current direction is negative downstream. The insulation material inside the LNI layer-wound coil strongly affects the quench propagation. When its thickness decreases, the equivalent radial thermal conductivity increases, thereby increasing the quench propagation velocity and current peak, and shortening the duration of the current response during quench.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"619 ","pages":"Article 1354477"},"PeriodicalIF":1.7,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140309327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Energy and exergy analysis of the cryogenic system for HTS magnets based on an open-cycle G-M/J-T cryocooler","authors":"Jingxin Zheng , Junjie Li","doi":"10.1016/j.physc.2024.1354478","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354478","url":null,"abstract":"<div><p>High-field magnets have been developed for a broad range of research applications. High-temperature superconducting magnets have received considerable attention due to their potential use in high-field applications. The High Magnetic Field Laboratory of the Chinese Academy of Sciences (CHMFL) is currently designing and constructing high-temperature superconducting (HTS) magnets which need the cooling capacity about 5 W to 10 W at 4.5 K in order to ensure the stability of the system. To meet their operational requirements, a miniature cryogenic system based on the Gifford-McMahon/Joule-Thomson (G-M/J-T) cryocooler has been designed and analyzed. In this research, the performance of the cryogenic system for HTS magnets is investigated systematically by employing both energy analysis and entropy analysis techniques. The results highlight the importance of several key factors, including high pressures, precooling temperature at cooling stages, and J-T exchanger efficiency, for improving the cooling capacity of the cryogenic system. Lowering the precooling temperature can enhance the system cooling capacity and also cause an increase in the precooling capacity. As the pressure increases, the cooling capacity of the system reaches its maximum point at 11.31 bar The J-T heat exchanger accounts for the largest exergy loss rate, 35.2–43.7%. The findings provide technical guidelines for the subsequent experiments and performance optimization <em>of cryogenic system.</em></p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"619 ","pages":"Article 1354478"},"PeriodicalIF":1.7,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140308551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jaemyung Cha , Jonghoon Yoon , JuKyung Cha , Uijong Bong , Seungyong Hahn
{"title":"A design study on MVAr class superconductor synchronous condenser with no-insulation HTS field coil","authors":"Jaemyung Cha , Jonghoon Yoon , JuKyung Cha , Uijong Bong , Seungyong Hahn","doi":"10.1016/j.physc.2024.1354458","DOIUrl":"https://doi.org/10.1016/j.physc.2024.1354458","url":null,"abstract":"<div><p>With the expansion of distributed power systems and renewable energy worldwide, the use of synchronous condensers (SC) has been gradually increasing to maintain the power quality of an electric grid. Because SC generates fewer harmonics and has the advantage of strengthening system inertia, it is considered as a primary option in Korea over other options such as Static Var Compensator (SVC) and STATic synchronous COMpensator (STATCOM). If superconductor synchronous condenser (SSC) is applied instead of SC, it brings more advantages: (1) it can minimize the adverse impact on the power system due to lower synchronous reactance, and (2) the higher power density can lead to many advantages in a limited area of substation. With these backgrounds, we report a design study on 40 MVAr SSC with no-insulation high-temperature superconductor (NI-HTS) field coil. Firstly, design criteria and procedures for electromagnetic design were set. Secondly, with the design procedure, the electromagnetic design having the minimum HTS conductor usage was obtained among the designs satisfying design criteria. Based on the final design, key characteristics of SSC including no-load voltage, the maximum flux density under the rated-load condition, V-curve characteristic, synchronous reactance, zero sequence reactance, negative sequence reactance, critical current, and NI-HTS characteristics were calculated by using finite element method. Lastly, the design comparison between SSC and SC was presented.</p></div>","PeriodicalId":20159,"journal":{"name":"Physica C-superconductivity and Its Applications","volume":"619 ","pages":"Article 1354458"},"PeriodicalIF":1.7,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140308555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}