（Na0.52K0.44Li0.04）Nb0.9-xSbxTa0.1O3 Lead-Free Piezoelectric Ceramics with High Performance and High Curie Temperature

（Na0.52K0.44Li0.04）Nb0.9-x Sbx Ta0.1O3 lead-free piezoelectric ceramics are prepared by a solid-state reaction method. With increasing Sb content, the transition temperature from orthorhombic to tetragonal polymorphic phase decreased. A composition （Na0.52K0.44Li0.04）Nb0.863Sb0.037Ta0.1O3 is found to possess excellent piezo- electric and electromechanical performances （d33 = 306pC/N, kp =48%, and kt=50%）, and high Curie temperature （Tc = 320 ℃）. These results indicate that （Na0.52K0.44Li0.04）Nb0.863Sb0.037 Ta0.1O3 is a promising lead-free piezoceramics replacement for lead zirconate titanate.     

Symmetric Telecloning and Entanglement Distribution of Spin Quantum States

We propose a physical realization of symmetric telecloning machine for spin quantum states. The concept of area average fidelity is introduced to describe the telecloning quality. It is indicated that for certain input states this quantity may come to an enough high level to satisfy the need of quantum information processing. We also study the properties of entanglement distribution via the spin chain for arbitrary two-qubit entangled pure states as inputs and find that the decay ratio of entanglement for the output states is only determined by the parameters of spin chain and waiting time, independent of the initial input states.     

Effects of Li Substitution and Sintering Temperature on Properties of Bi0.5（Na,K）0.5TiO3 Lead-Free Piezoelectric Ceramics

Bi0.5 （Na0.72K0.28- x Lix ）0.5 TiO3 （BNKLT- 100x） lead-free piezoelectric ceramics are synthesized by conventional solid state sintering techniques. The dielectric and piezoelectric properties of the BNKLT-100x ceramics as a function of Li content are systematically investigated. It is found that not only Li content but also the sintering temperature has a strong effect on the piezoelectric properties of BNKLT. The piezoelectric constant d33 Of BNKLT varies from 120 to 252pC/N in the Li content range from 0.03 to 0.16. In the sintering temperature range from 1080 to 1130℃, the d33 value of BNKLT-6 changes from 200pC/N to 252pC/N. The BNKLT-6 sample sintered at 1100℃ has the highest piezoelectric constant d33 of 252pC/N, with the electromechanical coupling factors kp of 0.32 and kt of 0.44.     

退火对Pb辐照Al2O3单晶发光特性的影响

研究了230MeV的²⁰⁸Pb²⁷⁺辐照Al₂O₃样品及随后在600,900,1100K高温条件下退火后的光致发光特性。从辐照样品的测试结果可以清楚地看到在波长为390,450nm处出现了强的发光峰。辐照量为1×10¹³ions/cm²时,样品的发光峰最强。经过600K退火2h后测试结果显示,380nm发光峰剧烈增强,而其他发光峰显示不明显。在900K退火条件下,380nm的发光峰开始减弱,而在360,510nm出现了明显的发光峰,至到1100K退火完毕后380nm的发光峰完全消失,而360,510nm的发光峰相对增强。从被辐照样品的FTIR谱中看到,波数在460~510cm^-1间的吸收是振动模式,经过离子辐照后,吸收带展宽,随着辐照量的增大,Al₂O₃振动吸收峰消失,说明Al₂O₃振动模式被完全破坏。1000~1300cm^-1之间为Al—O—Al桥氧的伸缩振动模式,辐照后吸收带向高波数方向移动,说明其振动模式受到影响。辐照剂量较小的样品,损伤程度相对较低,经退火晶化后,振动模式基本恢复到单晶状态;辐照剂量较高的样品,损伤程度大,退火处理后表面变得较粗糙,振动模式并未出现,说明结构破坏严重。     

椭圆型保偏光纤耦合器的研制

保偏光纤耦合器是干涉仪和光纤陀螺仪的关键器件。介绍了用匹配型椭圆包层保偏光纤制作保偏光纤耦合器的工艺流程、测试结果以及分光比随温度的变化情况。试验结果表明,保偏光纤耦合器的综合性能指标,尤其是附加损耗和温度性能达到了国内领先水平。     

采用罗戈夫斯基线圈诊断径向束流

 罗戈夫斯基线圈具有结构简单、高频特性好等特点而被广泛应用于脉冲电流测量。提出了用两个自积分式罗戈夫斯基线圈诊断径向束流的方法,在此基础上设计了两个用于径向束流诊断的自积分式罗戈夫斯基线圈,对其进行了标定。当标准电流的上升沿为30 ns时,罗氏线圈响应时间约为10 ns;整个系统的测量误差约为4.7%。从标定结果来看,该系统的频率响应特性和测量精度能够满足ns级束流诊断的要求,该方法可以用于径向结构高功率微波器件的束流强度测量。     

浅谈少学时普通化学的教学方法

对于少学时普通化学课程,为保证教学质量,必须采用有针对性的教学措施。本文结合课题组教师多年的教学经验,介绍了几种行之有效的教学方法。     

上转换激光晶体研究进展

本文综述近年来晶体材料的上转换过程研究进展，介绍了上转换发光晶体材料研究中的一些新动向以及在室温环境下，掺杂稀土离子的晶体上转换激光运转的成功经验，列举了几种室温上转换激光器的泵浦条件、发射波长、以及转换效率等参数，说明晶体材料的上转换激光技术已趋于实用化。     

Scalable and Robust Bio-inspired Organogel Coating by Spraying Method Towards Dynamic Anti-scaling

Scaling usually causes serious problems in daily life and industrial production. Currently, developing passive anti-scaling coatings has shown promises to overcome this problem. In this work, we fabricated a scalable and robust bio-inspired organogel(BIO) coating, showing dynamic scale resistance in the oil/brine mixture. The oil layer of the BIO coating was utilized as a barrier to inhibit scale nucleation and reduce scale adhesion. The mechanical strength of the coating was optimized by regulating nanoparticle contents. Moreover, the universality of scale resistance was demonstrated by varying the types of nanoparticles, oils and scales. Compared with commercial pipeline materials, such as copper, this BIO coating significantly reduces scale deposition after 240-h scaling test(ca. 93% reduction). Therefore, this study designs scalable and robust organogel coatings for sustainable scale resistance, which may be used for practical application in oil production.     

苯酚在Ti/PbO2电极上的电氧化反应

利用线性伏安法和恒电流电解法研究了苯酚在Ti／PbO2电极上的电催化氧化反应,通过电氧化过程中反应物和中间物的高效液相色谱测定,研究了苯酚在Ti／PbO2电极上电催化氧化的反应机理．实验发现,Ti／PbO2电极对水溶液中苯酚的电氧化具有显著的催化作用,25℃时,对初始浓度为2mmol／L的苯酚水溶液,恒定电流密度为50mA／cm2,电解3h,苯酚转化率为98．02％,有机碳去除率为54．36％．苯酚在Ti／PbO2电极上电催化氧化要经过对苯二酚或邻苯二酚、对苯醌、反丁烯二酸和草酸,最终变成二氧化碳和水的历程．第一步反应苯酚转化的主产物是对苯二酚．对苯二酚转化为苯醌和苯醌转化为反丁烯二酸的反应为慢反应,反丁烯二酸转化为草酸的反应为快反应．