Faddeev-Jackiw and the improved methods in quantization of the superconductive system

In this paper, we give the overview on Faddeev-Jackiw method and its improved one, as well as the relative studies recently and realize quantization of the superconductive system by the two methods, we get the same results by the two disposal methods. Furthermore, at convenience of the familiar study in this system, we take it as the application example and compare the two methods by dealing with this system from different aspects, demonstrate the improved Faddeev-Jackiw method is effective and significative, and represent the superiorities of the improved Faddeev-Jackiw method. We show that the improved method may simplify investigations of different complicated constrained systems.     

RSFQ的初步研究

RSFQ应用于高速电子计算机是近年来活跃在低温超导电子学领域的新兴课题。文中从约瑟夫逊效应的等效模型出发 ,阐述了 RSFQ电路的基本基理及基于节点约瑟夫逊相位的数值模拟方法 ,并把它用于一个 RSFQ单向缓冲器的瞬态分析 ,给出了其相位和电压波形     

Precipitation Behavior of Metal Ions in the Preparation of YBa2Cu3Oy and (Bi,Pb)2(Sr,Ca)4Cu3Oy Superconductive Materials in 8-Hydroxyquinoline-diethylamine Media

To prepare the YBa₂Cu₃O_y (Y-123) and (Bi, Pb)₂(Sr, Ca)₄Cu₃O_y (Bi-2223) superconductive materials, coprecipitation was used with 8-hydroxyquinoline (oxine) as precipitant to ensure complete precipitation. Various aspects of competitive reactions such as dissociation, precipitation, complex formation and association in the aqueous solution system containing metal ions, oxinate ion and diethylamine species have been explored in order to discover the optimal coprecipitation conditions of the title system. Experiments were conducted to confirm these conditions.     

Improved operation range of digital superconductive electronics by implementing passive phaseshifters

We implemented small superconducting loops containing a frozen single flux quantum in single flux quantum (SFQ) electronics. Such an element acts as a π-phaseshifter which is the missing complementary circuit element in SFQ electronics and can significantly improve the circuit reliability and robustness. We designed a four bit ripple counter including toggle flip-flops (TFF) with these π-phaseshifters. We analyzed the circuit stability by means of bit error rate (BER) measurements versus bias supply. The measured operation range of the counter in standard SFQ technique was ±14% and could be improved to ±24% for the new version utilizing π-phaseshifters. These results are a clear proof for a more robust circuit realization achieved without any additional power consumption. Furthermore, it supports the reduction of present power consumption in SFQ circuits by using smaller switching energy as well as the development of more complex circuits because of a reduced sensitivity against technological parameter spread.     

力学性能对Bi-2223/Ag超导带材临界电流影响实验研究

本文主要研究了在77K温度下,拉伸应变和弯曲应变对Bi-2223/Ag超导带材临界电流的影响,得到了超导带材的临界电流随拉伸强度、曲率半径变化规律.实验结果显明,拉伸作用在超导带材上产生的形变对其临界电流(Ic)的影响存在一个临界值εirr=0.3%.形变小于此临界值,Ic变化较小,超过此临界值,临界电流急剧下降.弯曲实验同样存在类似关系.同步辐射光源对超导带材检测表明,在形变情况下,超导氧化物陶瓷芯的微裂纹迅速增加和交织是Ic降低的主要原因.     

外场中超导结的直流约瑟夫逊电流的计算

外加磁场对超导体/半导体/超导体结的临界电流有一定影响。超导结的临界电流与磁场的曲线非常类似于单色光在单狭缝衍射的夫琅和费图样。该文在未考虑外加磁场的超导体/半导体/超导体结的临界电流的基础上,进一步对外加磁场的情形进行了研究,并对其结果借助M athem atica软件做了进一步的讨论。     

探索高Tc超导新材料的可能途径

本文从已有的实验与理论研究成果出发，分析和讨论了主导铜氧化物超导体转变温度Tc及其微观机制的各种外在和内禀的因素，在此基础上提出了进一步探索高Tc超导新材料的几种可能途径．     

不同幅值过电流下的高温超导线材失超发展过程

对高温超导材料的失超特性的研究是超导电力科学技术中的重要课题 ,为此 ,本实验室进行了大量的实验工作。在此基础上 ,文中整理了部分高温超导实验数据 ,对其进行分析和归纳总结 ,提出了高温超导线材失超三阶段理论     

高温超导薄膜衬底材料-SrTiO_3双晶的研究

SrTiO3双晶基片是高温超导电子学研究中外延YBCO薄膜所需要的基础材料;是制作高温超导量子干涉器件(SQUID)的核心。由于其特殊的制造工艺,加之研究因素所附加的高昂成本,至今只有少数国家涉足这一领域。文中展示作者在钛酸锶双晶研究方面所取得的阶段性进展。