Investigation of spontaneous magnetization of coupled 2×2 superconducting π ring array

We present the theoretical investigation of spontaneous magnetization of a coupled 2×2 πring array. It is indicated by free energy calculation that the system has the lowest energy when the four π rings have the full antiparallel configuration. Furthermore, the numerical evaluation results show that the system which favours full antiparallel spontaneous magnetization is a quantum effect deriving from the phase cohering of the superconducting quantum wavefunctions in the four superconducting rings through the shared Josephson junctions.     

超导π环零环混合阵列的自发磁化

研究了超导π环零环的混合规则阵列，计算了阵列的自由能.结果表明，两个π环通过中间零环间接耦合使得两π环反向自发磁化能量较低.规则阵列中，相邻π环倾向于反向自发磁化.这一现象起因于超导波函数的量子相干效应. 关键词： 超导结 π环 零环 自发磁化     

Development of 1.3GHz high-T-c rf SQUID

A new high-T_c (HT_c) rf SQUID working at around 1.3GHz has been developed to avoid electromagnetic interference such as growing mobile communication jamming. This new system works in a frequency range from 1.23 to 1.42GHz (centred at 1.3GHz), which is not occupied by commercial communication. The sensor used in the 1.3GHz rf SQUID is made of a HT_c coplanar superconducting resonator and a large-area HT_c superconducting film concentrator. We have achieved in the 1.3GHz HT_c rf SQUID system a minimal flux noise of 2.5×10^{-5}Φ_0/\sqrt{Hz} and a magnetic field sensitivity of 38fT/\sqrt{Hz} in white noise range, respectively. The effective area of the concentrator fabricated on a 15×15mm^2 substrate is 1.35mm^2. It is shown that the 1.3GHz rf SQUID system has a high field sensitivity. Design and implementation of 1.3GHz HT_c rf SQUID offers a promising direction of rf SQUID development for higher working frequency ranges.     

内腔多原子直接俘获的强耦合腔量子力学系统的构建

腔内中性原子的长时间控制与俘获一直是腔量子电动力学(QED)中的一个难题,极大地制约了人们相干操控单原子及其与光相互作用的研究.基于传统Fabry-Perot光学腔,设计了一套易于内腔原子操控的强耦合腔QED系统,其典型参数为:腔长3.5 mm精细度约为57000,(g0,κ,γ)=2π×(1.48,0.375,2.61)MHz,临界光子数和原子数分别为1.54和0.89.该系统的特点是:能够在腔内直接实现冷原子磁光阱,并建立腔内光学晶格,实现腔内可控数目的中性原子的长时间俘获.通过合理选择构建光学偶极阱和原子成像系统,可实现对腔内单个原子或原子阵列的操控、探测、成像等.该系统可以克服传统腔QED系统中转移原子的困难,大幅增加腔内原子的寿命,为构建以腔QED系统为基础的量子信息演示平台提供了一种可能.     

A new langbeinite‐type phosphate K2GdHf(PO4)3: synthesis,crystal structure,band structure and luminescence properties

Langbeinite‐type compounds are a large family that include phosphates, sulfates and arsenates, and which are accompanied by interesting physical properties. This work reports a new disordered langbeinite‐type compound, K₂GdHf(PO₄)₃ [dipotassium gadolinium hafnium tris(phosphate)], and its structure as determined by single‐crystal X‐ray diffraction. Theoretical studies reveal that K₂GdHf(PO₄)₃ is an insulator with a direct band gap of 4.600 eV and that the optical transition originates from the O‐2p→Hf‐5d transition. A Ce³⁺‐doped phosphor, K₂Gd_0.99Ce_0.01Hf(PO₄)₃, was prepared and its luminescence properties studied. With 324 nm light excitation, a blue emission band was observed due to the 5d¹→4f¹ transition of Ce³⁺. The average luminescence lifetime was calculated to be 5.437 µs and the CIE chromaticity coordinates were (0.162, 0.035). One may expect that K₂Gd_0.99Ce_0.01Hf(PO₄)₃ can be used as a good blue phosphor for three‐colour white‐light‐emitting diodes (WLEDs).     

超高效合相色谱法定性与定量分析补肾健脑颗粒

用超高效合相色谱法(Ultra performance convergence chromatography,UPC2)建立补肾健脑颗粒及各药材提取物的指纹图谱,对补肾健脑颗粒主要色谱峰进行归属分析,并测定有效成分β-蜕皮甾酮和松果菊苷的含量。样品经乙醇提取后,进样1μL,用Waters ACQUITY UPC2TMBEH柱(100 mm×3.0 mm,1.7μm)分离,柱温为40℃,以超临界CO2-0.05%H3PO4-甲醇溶液为流动相,梯度洗脱,流速为0.8 m L/min。分析补肾健脑颗粒和各药材提取物的UPC2指纹图谱,利用各峰相对保留时间、紫外光谱图及部分对照品归属主峰。结果表明,补肾健脑颗粒UPC2指纹图谱中15个主峰来源明确,其中12号峰为β-蜕皮甾酮,含量为380μg/g,15号峰为松果菊苷,含量为9.562 mg/g。与HPLC和UPLC法相比,本方法简便、快速,精密度高,重现性好。     

利用单通道高温超导磁梯度计获取心磁地图

根据自己研制的单通道高温超导rfSQUID磁梯度计在人体胸前测得的高信噪比的心磁信号,通过线性插值和高阶拟合,获得了人体心脏的一系列时序等强磁场地图,为高温超导SQUID磁强计、梯度计的心磁测量用于心脏病早期诊断和病理研究的进一步开展提供了思路和方向.     

ICP-AES测定山药中微量元素

用电感耦合等离子体-原子发射光谱法(ICP-AES)测定了山药中钾、钙、钠、镁、锰、铜、铁、锌8种微量元素的含量.8种元素的RSD分别为1.12%,0.69%,0.57%,0.28%,3.54%,2.23%,1.48%,2.49%.平均回收率为92.3%-102.2%,该方法灵敏度高,结果准确,可用于山药等中草药中多种...     

弱阴离子超高交联树脂固相萃取-高效液相色谱-紫外法测定人尿中高香草酸的含量

建立了人体尿液中高香草酸含量的固相萃取-高效液相色谱-紫外测定方法.合成了弱阴离子超高交联树脂固相萃取填料,并对其进行吸附性能考察.利用此萃取剂对尿液中的高香草酸进行选择性吸附,洗脱液富集后以甲醇-乙酸(15∶85,V/V)溶液为流动相,C18为固定相,于280 nm测定其中的高香草酸.方法验证结果表明,高香草酸在2.26～145 mg/L浓度范围内呈良好的线性关系;检出限为0.45 mg/L;方法的平均加标回收率大于90％;RSD小于4.2％.采用本方法对8名健康人尿样中的高香草酸含量进行了测定,结果为1.55～6.79 mg/L.表明本方法选择性好、灵敏度高、准确可靠.     

Mg/B多层膜退火法中不同制备条件对MgB2超导薄膜性质的影响

用Mg/B多层膜退火的方法制备了一系列MgB₂超导薄膜,研究了退火温度、退火时间和薄膜厚度对于MgB₂薄膜性质的影响.厚度为250 nm的Mg/B多层膜经400 ℃低温退火后已经生成超导相,此厚度薄膜750 ℃下退火20—30 min实现最佳超导转变温度（T_c）.前驱膜分层厚度相同时,随着薄膜厚度减小MgB₂薄膜T_c明显降低,而且较薄的膜T_{c关键词： 2}超导薄膜')" href="#">MgB₂超导薄膜 电子束蒸发 超导成相