Image charge effect on the light emission of rutile TiO_2(110) induced by a scanning tunneling microscope

The plasmon-enhanced light emission of rutile TiO_2(110) surface has been investigated by a low-temperature scanning tunneling microscope(STM). We found that the photon emission arises from the inelastic electron tunneling between the STM tip and the conduction band or defect states of TiO_2(110). In contrast to the Au(111) surface, the maximum photon energy as a function of the bias voltage clearly deviates from the linear scaling behavior, suggesting the non-negligible effect of the STM tip on the band structure of TiO_2. By performing differential conductance( dI/dV) measurements, it was revealed that such a deviation is not related to the tip-induced band bending, but is attributed to the image charge effect of the metal tip, which significantly shifts the band edges of the TiO_2(110) towards the Femi level(E_F) during the tunneling process. This work not only sheds new lights onto the understanding of plasmon-enhanced light emission of semiconductor surfaces, but also opens up a new avenue for engineering the plasmon-mediated interfacial charge transfer in molecular and semiconducting materials.     

Improved performance of Au nanocrystal nonvolatile memory by N_2-plasma treatment on HfO_2 blocking layer

The N_2-plasma treatment on a HfO_2 blocking layer of Au nanocrystal nonvolatile memory without any post annealing is investigated. The electrical characteristics of the MOS capacitor with structure of Al–Ta N/HfO_2/Si O2/p-Si are also characterized. After N_2-plasma treatment, the nitrogen atoms are incorporated into HfO_2 film and may passivate the oxygen vacancy states. The surface roughness of HfO_2 film can also be reduced. Those improvements of HfO_2 film lead to a smaller hysteresis and lower leakage current density of the MOS capacitor. The N_2-plasma is introduced into Au nanocrystal(NC) nonvolatile memory to treat the HfO_2 blocking layer. For the N_2-plasma treated device, it shows a better retention characteristic and is twice as large in the memory window than that for the no N_2-plasma treated device. It can be concluded that the N_2-plasma treatment method can be applied to future nonvolatile memory applications.     

运用CAFP教学提升学生化学意志素质的教学案例

鉴于当前学生化学意志素质缺乏的问题，探讨以认知、情绪唤醒、情感、意志为主控目标，在预习、尝试学习、交错搭配合作学习中，开展CAFP教学研究，以促成情意因素对认知的调动、动力、强化等功能。     

元素的起源与0号元素

论述元素的起源是以中子为起点,中子是特殊的0号元素。以中子的衰变特点、核反应的特点、与质子类同的特点、与稀有气体元素类同的特点以及中子星的存在、四中子的发现等论据,提出应当把中子看作元素并纳入元素周期表中。建议给这个特殊的元素命名为"中"。     

光纤腔耦合碳化硅薄膜的理论计算

半导体材料中的自旋色心是量子信息处理的理想载体,引起了人们的广泛兴趣.近几年,研究发现碳化硅材料中的双空位、硅空位等色心具有与金刚石中的氮-空位色心相似的性质,而且其荧光处于更有利于光纤传输的红外波段.然而受限于这类色心的荧光强度和谱线宽度,它们在量子密钥分发和量子网络构建等方面的实际应用依然面临严峻的挑战.利用光学腔耦合自旋色心实现荧光增强和滤波将能有效地解决这些难题.将光纤端面作为腔镜,并与自旋色心耦合可以实现小模式体积的腔耦合,而且天然地避免了需要再次将荧光耦合进光纤而造成损耗的缺点.本文理论计算了耦合碳化硅薄膜的光纤腔的性质和特征.首先通过优化各项参数包括薄膜表面粗糙度、腔镜反射率等,理论分析了存在于光纤腔中的不同模式的特点,以及光纤腔耦合色心的增强效果及相关影响因素.进一步地研究了对开放腔而言最主要的影响因素—振动对腔性质、色心的增强效果以及耦出效率的影响,最终得到在不同振动下的最大增强效果以及对应的耦出透射率.这些结果为今后光纤腔耦合色心的实验设计提供了最直接的理论指导,为实验的发展和优化指明了方向.     

基于IgY的ELISA定量检测甲鱼系统性败血症球状病毒

为了对甲鱼系统性败血症球状病毒(STSSSV)进行快速检测,以抗STSSSV卵黄抗体(egg yolk immunoglobulin,Ig Y)为一抗,以羊抗鸡Ig G(HRP-Ig G)为二抗,建立STSSSV检测的间接酶联免疫吸附(ELISA)与血凝抑制(HI)实验,对两者进行了比较.运用ELISA对感染病毒甲鱼的血清、肝脏、粪便、及饲养环境水样进行了STSSSV检测.用ELISA分析了病毒稀释倍数及其2的对数值与OD492nm值间的线性关系,建立STSSSV的ELISA定量检测方法.结果显示:ELISA较HI更灵敏,其对STSSSV的检测灵敏度为3.98 ng·m L-1,能够在携带该病毒尚未显症的隐性感染的甲鱼血清和甲鱼粪便与养殖水中检测出STSSSV.ELISA对其他水产病毒无交叉反应,特异性强.ELISA定量检测限度范围为0.031~4μg·m L-1.本研究建立的间接ELISA方法为STSSSV的定性、定量提供了准确有效的检测手段.     

Cu/SiO2催化剂在草酸二乙酯加氢过程中失活研究

草酸酯加氢合成乙二醇过程中负载量为20％的Cu催化剂可以获得较高的乙二醇(EG)收率,但是该催化剂寿命过短的问题限制了其工业应用.本实验主要研究造成该催化剂失活的原因.使用蒸氨法将铜负载在SiO2上,制成用于草酸二乙酯(DEO)加氢的催化剂.运用X射线衍射(XRD)、程序升温还原(TPR)和高分辨率透射电镜(HRTWE...     

常温下 MnO2/Al2O3催化剂催化臭氧氧化甲苯反应

采用浸渍法制备了Al2O3负载的5种过渡金属氧化物催化剂,考察了它们在常温下催化臭氧氧化甲苯的性能,并运用程序升温还原、程序升温氧化、N2吸附-脱附和X射线光电子能谱对催化剂进行了表征.结果表明,NiO/Al2O3,CoO/Al2O3和MnO2/Al2O3催化剂上活性氧中心数量较少,臭氧与甲苯转化率较高;而Fe2O3/...