机械磨抛对CdZnTe薄膜阻变特性的影响

采用磁控溅射法在ITO玻璃上制备了CdZnTe薄膜,探究机械磨抛对CdZnTe薄膜阻变特性的影响。通过对XRD图谱、Raman光谱、AFM显微照片等实验结果分析阐明了机械磨抛影响CdZnTe薄膜阻变特性的物理机制。研究结果表明,磁控溅射制备的薄膜为闪锌矿结构,F43m空间群。机械磨抛提高了CdZnTe薄膜的结晶质量;CdZnTe薄膜粗糙度(Ra)由磨抛前的3.42 nm下降至磨抛后的1.73 nm;磨抛后CdZnTe薄膜透过率和162 cm^-1处的类CdTe声子峰振动峰增强;CdZnTe薄膜的阻变开关比由磨抛前的1.2增加到磨抛后的4.9。机械磨抛提高CdZnTe薄膜质量及阻变特性的原因可能是CdZnTe薄膜在磨抛过程中发生了再结晶。     

SnSxSe2-x单晶纳米片的可控制备与表征

锡二硫族化合物可以通过改变硫和硒的含量来连续调控三元合金材料的带隙、载流子浓度等物理化学性质,在电子和光电子器件应用上具有巨大的潜力。本文采用化学气相沉积(CVD)技术可控地制备了不同元素组分的SnS_xSe_2-x(x=0,0.2,0.5,0.8,1.0,1.2,1.5,1.8,2.0)单晶纳米片。采用扫描电子显微镜(SEM)、原子力显微镜(AFM)、能量色散X射线光谱(EDS)、透射电子显微镜(TEM)以及拉曼光谱等手段对SnS_xSe_2-x纳米片进行了综合表征。结果表明本方法成功实现了元素百分比可调的SnS_xSe_2-x单晶纳米片的可控制备。重点研究了依赖于元素百分比的SnS_xSe_2-x的拉曼特征谱,实验结果与基于密度泛函理论(DFT)的第一性原理计算得到的SnS_xSe_2-x的拉曼仿真谱高度吻合,理论计算结果较好地诠释了实验拉曼光谱发生变化的原因。本研究提供了一种元素百分比可调的三元SnS_xSe_2-x单晶纳米片的可控制备方法,同时对锡二硫族化合物的明确、无损识别提供了方案。     

石英晶体板非线性高频振动的拓展伽辽金法分析

针对考虑几何和材料非线性的石英晶体板厚度剪切振动和弯曲振动的方程组,利用扩展伽辽金法对该方程组进行转化和求解,分别获得了强烈耦合的厚度剪切振动模态和弯曲振动模态的频率响应关系,绘制了不同振幅比和不同驱动电压影响下的频率响应曲线图。数值计算结果表明可以选取石英晶片的最佳长厚比尺寸来避免两种模态的强烈耦合。驱动电压的变化将引起石英晶体谐振器厚度剪切振动频率的明显改变,必须将振动频率的漂移值控制在常用压电声波器件的允许值之内。扩展伽辽金法对石英晶体板非线性振动方程组的求解为非线性有限元分析和偏场效应分析奠定了基础。     

In-situ electrochemical study of chalcopyrite pressure oxidation leaching from 110 °C to 150 °C under saturated vapor pressure

Pressure oxidation leaching behavior of chalcopyrite in sulfuric acid solution from 110 °C to 150 °C were investigated by in-situ electrochemical methods. Leaching experiments under saturated vapor pressure conditions were used to simulate the anoxic environment that may be encountered in industrial applications. Scanning electron microscope and X-ray photoelectron spectroscopy were used to characterize the morphology and the chemical status of chalcopyrite surface. Results show that the copper extraction was increased with the increase of leaching temperature. Under the optimal leaching conditions under saturated vapor pressure, the copper and iron extraction are 8.3% and 29.8%, respectively. When the temperature increased from 110 °C to 150 °C, the self-corrosion potential and electrochemical reaction resistance firstly increased and then decreased. In contrast, the resistance of the passive film was always increased with the increase of temperature. The electrochemical study results indicated that the increase in temperature affected the oxidation of chalcopyrite by altering the kinetics of the cathodic reaction and the anodic passivation. Both the self-corrosion current density (i_corr) and rate constant were affected by the reduction of Fe(III). The XPS results show that elemental sulfur and H₃O(Fe₃(SO₄)₂(OH)₆) were the main leaching solid products. The formation of H₃O(Fe₃(SO₄)₂(OH)₆) not only caused a decrease in cathodic reaction kinetics, but also increased the resistance of mass transfer process. Due to the faster release of iron, copper-rich sulphides were formed, which mixed with the elemental sulfur and/or H₃O(Fe₃(SO₄)₂(OH)₆) led to coverage of the chalcopyrite surface.     

In-situ cation exchange enhances room temperature phosphorescence of a family of metal-organic frameworks

The rational designability and chemical tunability of metal-organic frameworks(MOFs)are enabling tributes to efficaciously enhance their room temperature phosphorescence(RTP)performance.A family of stable anionic MOFs,[Zn₂(4,5-ImDC)₂]M₂(NKU-132,M=(CH₃)₂NH₂or(CH₂CH₃)₂NH₂),featuring significant RTP have been synthesized.By rational cation selection and in-situ replacement from dimethylammonium to diethylammonium,the phosphorescence lifetime is increased from 30.88 to126.3 ms,along with less sensitivity to air.This work provides an anti-quenching and lifetime tuning example for RTP-MOFmaterials via facile host-guest chemistry.     

Shock waves in gas flows with nanoparticles

Journal of Thermal Analysis and Calorimetry - The paper focuses on the analytical analysis of the propagation of a normal shock wave in an adiabatic gas flow with nanoparticles. A modified...     

Nonseparating Independent Sets and Maximum Genus of Graphs

Acta Mathematicae Applicatae Sinica, English Series - A subset I of vertices of an undirected connected graph G is a nonseparating independent set (NSIS) if no two vertices of I are adjacent and G...     

Numerical Simulation of a Multi-Output Radar Orthogonal Waveform Based on a Chaos Optimization Algorithm

Russian Physics Journal - Aiming at problems of low probability of interception and poor anti-jamming performance of the multi-output radar, the numerical simulation based on a chaos optimization...