Effects of preparation parameters on growth and properties of β-Ga2O3 film

The Ga$_{2}$O$_{3}$ films are deposited on the Si and quartz substrates by magnetron sputtering, and annealing. The effects of preparation parameters (such as argon-oxygen flow ratio, sputtering power, sputtering time and annealing temperature) on the growth and properties ($e.g.$, surface morphology, crystal structure, optical and electrical properties of the films) are studied by x-ray diffractometer (XRD), scanning electron microscope (SEM), and ultraviolet-visible spectrophotometer (UV-Vis). The results show that the thickness, crystallization quality and surface roughness of the $\beta $-Ga$_{2}$O$_{3}$ film are influenced by those parameters. All $\beta $-Ga$_{2}$O$_{3 }$films show good optical properties. Moreover, the value of bandgap increases with the enlarge of the percentage of oxygen increasing, and decreases with the increase of sputtering power and annealing temperature, indicating that the bandgap is related to the quality of the film and affected by the number of oxygen vacancy defects. The $I$-$V$ curves show that the Ohmic behavior between metal and $\beta $-Ga$_{2}$O$_{3}$ films is obtained at 900 ${^\circ}$C. Those results will be helpful for the further research of $\beta $-Ga$_{2}$O$_{3}$ photoelectric semiconductor.     

心电信号无失真压缩编码的研究

本文分析了心电信号的特点及其统计特性,提出了两种无失真压缩编码的方案,即双码长与四码长方案,它们的压缩系数都在0.5左右,尽管编码效率不及Huffman编码,但要简单得多,便于用软件或硬件实现。     

砷化镓半导体外延层的电子声成像

本实验利用扫描电子声显微镜对ＣａＡｓ半导体外延片生长缺陷进行了电子声成像。通过分析不同条件下获得的电声图像，讨论了ＣａＡｓ半导体外延片在电声成像中其电声信号的产生机制。实验结果显示这种成像技术在半导体材料微观分析与评价中具有巨大的应用前景。     

电流反馈的高次微分示波极谱滴定法

在高次微分示波极谱滴定法中,利用电流反馈技术对充电电流进行补偿,可使高次微分示波极谱图上去板剂切口的灵敏度进一步提高。当切口电位处的|dC_d/dE|或|d²C₄/dE²|值相对较小时,电流反馈的作用就较明显。利用电流反馈高次微分示波极谱滴定法以氨羧络合剂滴定了Cd²⁺、Ni²⁺、Co²⁺、Pb²⁺、Zn²⁺,用Zn²⁺返滴定法测定了Al-Ni合金中的Ni,终点变化敏锐。     

基于姜黄素负载的上转换纳米传感体系测定生物样品中的铜离子

通过高温共沉淀法制备了发光效率高、形貌规则、粒径均一的上转换纳米粒子;采用反相微乳法合成二氧化硅壳层(SiO₂),实现上转换纳米粒子从油相到水相的转移;将介孔二氧化硅壳层(mSiO₂)包覆在上转换纳米粒子表面,荧光响应分子姜黄素被负载在m SiO₂的孔道中。基于荧光共振能量转移的原理,构建“Turn on”纳米传感体系,并用于Cu²⁺的检测,检测线性范围为10～50μmol/L,检出限为0.5μmol/L。本方法可实现大鼠血清样品中Cu²⁺的检测。