300kW超导单极电机低温技术及试验研究

简述了３００ｋＷ超导单极电机试验的低温系统，介绍了超导单极电机的磁体低温系统及液氦、液氮冷却，输液及运行情况，分析比较了多次试验研究的结果。     

高温超导材料及其应用前瞻

高温超导材料产业化进程的不断加快使得超导材料的应用领域越来越广。本文分别描述了第一代与第二代高温超导带材的优劣势等,并对其应用前景进行了分析,详细介绍了超导材料在超导电机、超导电缆等领域的应用情况,并对高温超导材料未来的应用前景进行了分析。     

A Coherent Two-Level System in a Superconducting Single-Electron Transistor Observed Through Photon-Assisted Cooper-Pair Tunneling

A coherent two-level system can be constructed in an ultrasmall Josephson-junction circuit, where two charge states are coupled by single Cooper-pair tunneling. To investigate coherence and decoherence in the two-level system, we have measured dc current through a voltage-biased superconducting single-electron transistor. Under microwave irradiation, a current due to photon-assisted Cooper-pair tunneling is induced, which serves as a useful experimental tool for spectroscopic study of the energy levels in the two-level system. We observed energy-level splitting, which is evidence of the coherent superposition of the two charge states.     

Evaluation of Cathode Electrodes in Lithium-Ion Battery: Pitfalls and the Befitting Counter Electrode

Boosting energy density and reducing the cost of lithium-ion batteries are critical to accelerating their applications in transportation and grid energy storage. Battery design with increasing electrode thickness is an effective way to combine higher energy density and lower cost. However, the evaluation of electrodes with increased thickness is challenging and requires more attention. Here, some pitfalls are to be avoided and a reasonable evaluation strategy is provided for cathode electrodes regarding the choice of counter electrode. Though as the most common counter electrode, lithium metal anode is actually not suitable for evaluating cycling performance, which exhibits fast cell capacity decline, especially, in the case of areal capacity higher than 2 mAh cm⁻². Two commercial anode materials, graphite and Li₄Ti₅O₁₂ (LTO) as the potential alternatives, are systematically evaluated and compared, demonstrating LTO as the more suitable choice. The thick cathode electrode coupled with LTO exhibits excellent rate capability, stable cycling performance, and easy interpretation of charge/discharge profile. The relationship between cell balance and battery performance is further analyzed in detail. This strategy enables a reasonable evaluation of the cathode electrodes and advances the designing of thick electrode.     

高压电瓷废料制备低密度高强度陶粒支撑剂及其性能

以高压电瓷废料为原料,通过气流超细粉碎、圆盘造粒,经1180～1260℃烧结制备油气开采水力压裂用陶粒支撑剂.通过X射线衍射(XRD)和扫描电子显微镜(SEM)对不同烧结温度陶粒支撑剂试样的物相组成和微观形貌进行分析,通过石油天然气行业标准中的方法测试试样的密度、破碎率及酸溶解度,研究烧结温度对试样微观结构和性能的影响.结果表明,支撑剂主要物相为莫来石和刚玉,随着烧结温度的升高,针状莫来石晶粒逐渐长大,并互相交错堆叠形成网格状结构,液相均匀分散并包裹于晶粒,使试样致密化程度提高.但烧结温度过高会导致试样内二次莫来石化程度变高,部分莫来石晶粒异常长大,使支撑剂整体表现出高的空隙率,影响试样强度.试样在1220℃表现出最高视密度和最低破碎率,在69 MPa闭合压力下其破碎率仅为6.1％、视密度为2.74 g/cm3,符合SY/T5108-2014中关于低密度陶粒支撑剂的标准要求.     

梳状电极结构对大气压表面放电的影响

研究了梳状电极结构对大气压表面放电的影响,发现频率固定时放电电流随着外加电压的增加而增加,而电压固定时在某个频率范围内放电电流有最大值;在相同的电压和频率下较宽的电极条宽可以产生较大的放电电流,而电极条间距对放电电流几乎没有影响;用整块金属板做接地电极相比于梳状接地电极可以产生较大的放电电流;另外,较厚的高压电极可以在介质板表面产生更明亮、厚度更大的放电等离子体.     

On the Power Handling Properties of High Temperature Superconducting Microwave Contiguous Duplexer

The power handling properties of a high temperature superconducting (HTS) microwave contiguous duplexer are measured in this letter. The HTS contiguous duplexer was fabricated using YBa₂Cu₃O₇ (YBCO) thin films on a 0.5-mm-thick LaA1O₃ substrate, operation frequencies of which are centered at 3.25 GHz and 3.75 GHz with 500-MHz-wide channels. The tested frequency response of power handling property of the HTS contiguous duplexer shows that there is a decreased power handling property on the crossover region; however, this microwave nonlinearity does not affect the engineering application of HTS contiguous duplexers and multiplexers.     

高压气体终端净化技术在标准气体配制中的应用

介绍了气体高压净化技术在标准气体制备中的应用,随着标准气体制备难度加大及市场竞争加剧,该技术将得到广泛的应用。多年的实验结果表明该技术具有广阔的市场空间。     

Observation of a Possible Metallic State Induced by a Parallel Magnetic Field in Superconducting Au0.7In0.3 Samples With Very Low Normal-state Sheet Resistance

We report the observation of an apparent metallic state induced by a parallel magnetic field in Au_0.7In_0.3 samples with very low normal-state sheet resistance. These samples can be modeled as a random array of superconductor-normal metal-superconductor (SNS) junctions. For both the thin planar and cylindrical films, the magnetic field was applied parallel to the substrate of the sample and measurement currents. For the mesoscopic rings, however, a perpendicular field was used. Our electrical transport and tunneling measurements suggest that the samples consist of superconducting In-rich islands not linked by Josephson coupling in the metallic state. The physical origin of the metallic state is discussed.      

Transport Properties in Gases at High Temperature and Low Pressure: Comparison of Kinetic Theory with Direct Simulation Monte Carlo

Expressions for the transport coefficients obtained from the Gross-Jackson and the Chapman–Enskog methods are used to derive explicit relations incorporating the internal energy of the molecules for pure polyatomic gases and for binary mixtures of gases. Various coefficients such as the binary diffusion, thermal conductivity, and the viscosity coefficients and the thermal diffusion factor are calculated and a comparison with the direct simulation Monte Carlo (DSMC) method is carried out. The results show that the contribution of the internal energy is important and cannot be neglected.     

析氢催化电极的研究现状

综述了析氢反应中高催化活性电极的现状，并对析氢催化机理进行了评述。     

Steps Toward Application of Photoinduced Phenomena in Superconducting Devices

The interaction of electromagnetic radiation with thin film devices consisting of superconducting, normal conducting, semiconducting, insulating, and magnetic materials can be used for variety of different applications. Some examples will be discussed, including laser modification for patterning and adjustment of thin film high-T_c superconducting devices, ultrafast response, and the photoinduced superconductivity in high-T_c materials which offers interesting possibilities for optoelectronical conversation and controllable weak links in superconducting electronics.     

舰船电力系统用1 MJ高温超导储能磁体设计研究

介绍了舰船电力系统用的1MJ螺管型高温超导储能磁体的设计优化步骤，给出了用Bi-2223超导带进行1 MJ磁体线圈的设计和优化结果，分析了高温超导体的各向异性对磁体临界电流的影响，讨论了储能容量一定的多螺管磁体系统在漏磁、储能密度和所需超导线材方面的变化。     

低气压下占空比对细长管空心阴极辉光放电电流的影响

为了在细长管内壁获得性能良好质地均匀的膜层,本文在低气压条件下、采用细长管作真空阴极进行空心阴极辉光等离子体放电。通过研究对多种气氛(纯Ar、纯N₂、氮气氩气混合)下平均电流、电流峰值的实时测量对比了不同脉冲占空比条件下等离子体放电流,讨论和分析了多气氛下改变占空比所带来的影响。实验结果显示使用频率为40 kHz的脉冲电源,随着占空比变化,脉冲电流波形有显著变化。不同气氛波形不同,但是峰值均提高,平均电流也都上升,纯Ar气氛从20%占空比提高到70%占空比电流峰值从0.325 A上升到了0.5 A,平均电流由0.12 A上升到了0.28 A。测量管内不同位置电流的值,发现管内整体电流均匀性纯Ar和混合气氛优于纯N₂,Ar在30%~60%占空比区间内,表征均匀性的参数K30%~60%≈0.12。     

窄流道式MOCVD制备YGBCO超导层研究

金属有机化学气相沉积能连续、快速的沉积高温超导带材YBa₂Cu₃O_7-x (YBCO) 超导层。但金属有机源的利用率与薄膜沉积速率以及沉积一致性难以兼顾, 制备YBCO高温超导带材的成本居高不下。本文提出了一种新的窄流道式反应室以改进薄膜沉积的一致性。在200 mm长度腔体中沉积的280 nm厚的Y_0.5Gd_0.5Ba₂Cu₃O_7-x薄膜J_c分布在3.2~3.5 MA/cm² (77 K, 0 T), 面外、面内半高宽值分别在1.39°~1.49°和1.88°~2.13°, 表面平整致密。YBCO薄膜良好的一致性表明该窄流道反应室对制备YBa₂Cu₃O_7-x超导带材有好的实用性。