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采用简单的热解-硫化两步法成功制备了一种新型的富氮掺杂碳空心纳米笼(NC)负载双元金属硫化物纳米颗粒(CoNixSy)的复合材料 CoNixSy/NC。该策略以丁二酮肟镍为镍源,增加了活性位点,同时前驱体 ZIF-8@Ni-ZIF-67的核壳结构为空心碳纳米笼的构建提供了可能性。这种独特的负载多金属硫化物纳米颗粒的中空结构使CoNixSy/NC作为电极材料时具有更多的活性位点、更高的导电性和结构稳定性,从而使其具有较高的比容量(1 A·g-1时比容量为629.2 F·g-1),优异的循环稳定性(1 A·g-1下1 000次循环测试后容量保持率为93.4%)。当将其进一步组装成对称超级电容器后,在1 A·g-1下可提供207.2 F·g-1的比电容,1 000圈循环稳定后的容量保持率为85.36%。 相似文献
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Rhenium is a superconductor with a relatively weak tendency to oxidize, which is advantageous in superconducting quantum circuit and qubit applications. In this work, Re/A1-A1Ox/Re Josephson tunnel junctions were fabricated using a selective film-etching process similar to that developed in Nb trilayer technology. The Re films had a superconducting transition temperature of 4.8 K and a transition width of 0.2 K. The junctions were found to be highly reproducible using the fabrication process and their characteristics had good quality with a low leakage current and showed a superconducting gap of 0.55 meV. 相似文献
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Nb/Al-AlOx/Nb tunnel junctions are often used in the studies of macroscopic quantum phenomena and superconducting qubit applications of the Josephson devices. In this work, we describe a convenient and reliable process using electron beam lithography for the fabrication of high-quality, submicron-sized Nb/Al-AlOx/Nb Josephson junctions. The technique follows the well-known selective Nb etching process and produces high-quality junctions with Vm=100 mV at 2.3 K for the typical critical current density of 2.2 kA/cm^2, which can be adjusted by controlling the oxygen pressure and oxidation time during the formation of the tunnelling barrier. We present the results of the temperature dependence of the sub-gap current and in-plane magnetic-field dependence of the critical current, and compare them with the theoretical predictions. 相似文献
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Nb/Al-AlOx/Nb tunnel junctions with controllable critical current density Jc are fabricated using the standard selective Nb etching process.Tunnel barriers are formed in different oxygen exposure conditions (oxygen pressure P and oxidation time t),giving rise to Jc ranging from 100 A/cm2 to above 2000 A/cm2.Jc shows a familiar linear dependence on P × t in logarithmic scales.We calculate the energy levels of the phaseand flux-type qubits using the achievable junction parameters and show that the fabricated Nb/Al-AlOx/Nb tunnel junctions can be used conveniently for quantum computation applications in the future. 相似文献
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Shou-Kuan Zhao 《中国物理 B》2022,31(3):30307-030307
The Loschmidt echo is a useful diagnostic for the perfection of quantum time-reversal process and the sensitivity of quantum evolution to small perturbations. The main challenge for measuring the Loschmidt echo is the time reversal of a quantum evolution. In this work, we demonstrate the measurement of the Loschmidt echo in a superconducting 10-qubit system using Floquet engineering and discuss the imperfection of an initial Bell-state recovery arising from the next-nearest-neighbor (NNN) coupling present in the qubit device. Our results show that the Loschmidt echo is very sensitive to small perturbations during quantum-state evolution, in contrast to the quantities like qubit population that is often considered in the time-reversal experiment. These properties may be employed for the investigation of multiqubit system concerning many-body decoherence and entanglement, etc., especially when devices with reduced or vanishing NNN coupling are used. 相似文献
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为研究孤立煤体在采空区侧向支承应力、超前支承应力、断层切割形成的地堑结构等因素的耦合作用下诱发冲击地压事故的发生机理,采用现场实测、数值模拟等手段,分析了孤立煤体从形成到发生冲击地压事故期间的应力、塑性区演化过程。研究发现:2305S工作面受相邻采空区侧向支承应力作用,影响范围约210 m,应力峰值55.81 MPa; 2305S工作面推采至105 m时超前工作面45 m处应力峰值约为52.23 MPa;工作面推采至250 m时,在工作面前方41 m处应力值达70.96 MPa,应力集中系数达2.90;工作面推采至250 m时“见方”效应显现强烈,使孤立煤体区域应力集中程度加剧;同时2304S工作面采空区也使得楔形地堑区岩层沿高倾角断层面滑移,挤压孤立煤体区域,造成工作面断层三角区煤体应力进一步集中,从而诱发冲击地压。 相似文献
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基于数据仓库的决策支持系统的体系结构 总被引:3,自引:0,他引:3
传统决策支持系统由于其功能的不足,不能满足现代企业的决策需求,而数据仓库技术是解决该问题的有效途径之一.文章分析了数据仓库技术在决策支持系统中的应用现状,提出了一种基于数据仓库的决策支持系统的体系结构,详细讨论了该体系结构中的数据仓库系统的结构,并简要介绍了相关的联机分析处理与数据挖掘技术. 相似文献
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本光学实验自动命题系统可以减轻教师在实验理论考试前命题的工作量,出题随机性好,生成的试卷直接打印输出,系统提供比较友好的操作界面.题库结构通用性较好,可以方便地改型为其他实验题库. 相似文献
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随着信息技术的飞速发展 ,利用光作为信息传输、存储、处理工具的光电子信息技术将得到广泛的应用 .电光调制器是将电信号调制到光束上的电光器件 ,在光通讯领域有十分重要的应用背景[1~ 5] .与通常基于无机材料 (如 ,LiNbO3 、KH2 PO4晶体等 )的电光调制器相比 ,基于聚合物材料的电光调制器具有非线性光学系数大、能量损耗低 (聚合物材料的介电常数很低 )和制作方法简单等优点[6,7] .因此 ,可应用于聚合物电光调制器的新材料是最近一、二十年来研究的热点和前沿 ,受到人们的广泛关注 .通常Mach Zehnder聚合物电光调制器具有“三明治”… 相似文献