La0.67Ca0.33MnO3薄膜中的各向异性应变与电荷有序

本文采用脉冲激光沉积法在NdGaO3(001)单晶衬底上制备了一系列的La0.67Ca0.33MnO3薄膜,实验主要研究了薄膜的输运性质.La0.67Ca0.33sMnO3块材是铁磁金属基态,而La0.67Ca0.33MnO3/NdGaO3(001)薄膜由于各向异性应变的存在,可以观测到电荷有序绝缘相的出现.薄膜样品表...     

大气微波等离子体炬装置设计及实验研究

大气微波等离子体矩具有无电极放电污染、无需昂贵真空设备和易于连续化加工等特点,具有广阔的应前景.本文设计了一套基于BJ26波导的微波能利用率高、稳定性好的大气微波等离子体装置.该装置由最高输出功为800W的2.45GHz程控微波源、调配系统、波导谐振腔和耦合天线组成.利用加装游标卡尺的接触式短路活塞,微波反射面位置进行...     

Revisiting H/Pt(111) by a combined experimental study of the H-D exchange reaction and first-principles calculations

We report a detailed investigation of the behavior of chemisorbed hydrogen atoms (Ha) on Pt(111) by a combination of an ex-perimental study of the Ha + Da reaction and first-principles calculations. The coverage-dependent adsorption and desorption behavior of Ha and Da on Pt(111) have been systematically established and can be well interpreted in terms of repulsive inter-actions between adsorbates. Ha adsorbs exclusively on the face-centered cubic (fcc) sites of Pt(111) at coverages not exceeding 1 monolaye...     

YAG复合型相位共轭腔对改善光束模式的研究

如何降低受激布里渊散射(SBS)相位共轭腔的启动阈值以及如何提高输出光束的质量一直是人们关心的课题。报道了在YAG激光器上运行一种复合型受激布里渊散射相位共轭激光腔,该腔能够输出模式优良的光束。最大能够输出13．35mJ的单纵模,脉冲半高宽度约为15ns,输出光束的发散角为0．6mrad。实验给出了不同参量条件下的输出脉宽、能量及远场光斑分布和干涉环的情况,表明利用复合型相位共轭腔是改善光束模式的一种简单有效的方法。     

Development of an optical probe to measure the flattened area of ocular cornea

The optical probe in tonometers is a key component in measuring the flattened diameter or area of the ocular cornea. A new kind of optical probe for the direct measurement of the flattened area of the ocular cornea is presented. The optical probe uses the cone prism with a modulating flake of light intensity as its measuring body. The test results on simulated eyeballs with different radii of curvature of the ocular cornea show that there is a linear relation between the flattened area of the ocular cornea and the normalized current. The optical probe, which is more compact compared with existing optical probes and easily configured with its coaxiality of optical parts, may be an excellent probe for constructing a low-cost, miniaturized applanation tonometer.     

原子吸收光谱法测定鸡蛋中营养元素的前处理方法研究

本文分别采用０．１ｍｏｌ·Ｌ－１盐酸、６ｍｏｌ·Ｌ－１盐酸、ｐＨ７．０１ｍｏｌ·Ｌ－１ＮＨ４Ａｃ振荡提取及６ｍｏｌ·Ｌ－１盐酸煮沸法测定了鸡蛋中Ｋ、Ｎａ、Ｍｇ、Ｃａ、Ｚｎ、Ｆｅ、Ｍｎ、Ｃｕ八种元素,并与经典前处理方法即现在普遍采用的浓硝酸－高氯酸全消化法及干灰法进行比较,结果表明,对于大量元素Ｋ、Ｎａ、Ｍｇ几种提取方法与经典法接近,回收率达９０％～１１５％;微量元素Ｚｎ、Ｍｎ、Ｆｅ也可分别用ｐＨ７．０１ｍｏｌ·Ｌ－１ＮＨ４Ａｃ,０．１ｍｏｌ·Ｌ－１盐酸、６ｍｏｌ·Ｌ－１盐酸振荡提取,回收率在１００％～１１５％之间,Ｃｕ则可用６ｍｏｌ·Ｌ－１盐酸煮沸法测定,回收率较理想。而Ｃａ这几种方法提取结果均不理想,主要因增感作用,造成结果偏高。经典干灰化结果偏低,灰化温度达４５０℃,即可造成多种元素损失,且繁琐费时。本文采用的几种提取方法简单、快速,结果准确性、精度可达到分析要求。     

SmFeAsO0.78F0.22中Mn掺杂对超导电性的抑制效应

本文报道了Mn替代Fe对最佳掺杂的Sm-1111体系超导电性的影响.通过电输运及磁性质的测量发现Mn对Fe的替代迅速抑制了超导电性.随着Mn含量的增加,体系的电阻率ρ和磁化率M逐渐增大.对于低掺杂x＜0.25%和未掺杂样品,M接近零,对于≤1%,M从室温到超导转变几乎不变,实验指出Fe2+失去其磁性.我们提出这是由于F...