镍掺杂铁酸铋薄膜的电磁性能研究

利用溶胶-凝胶工艺在ITO/玻璃衬底上制备了纯相铁酸铋(BiFeO3,BFO)和镍掺杂铁酸铋(BiFe09Ni0.1O3,BFNO)薄膜.X-射线衍射(XRD)测试表明纯相和镍掺杂铁酸铋分别为扭曲钙钛矿结构和四方相结构,具有不同的空间对称性.镍掺杂后(012)衍射峰宽化,峰强变弱,说明晶粒变小,并由原子力显微镜(AFM)测试得到验证.镍掺杂铁酸铋具有更大的介电常数和较小的漏电流.铁电测试仪和振动样品磁强计(VSM)测试结果表明镍的掺入可以迸一步提高铁酸铋的室温铁电性和铁磁性.     

中学化学教学设计中连续性问题情境的类型研究

运用连续性问题情境进行教学设计时,无论是元素化学的教学内容,还是概念原理的教学内容,连续性问题情境之间都有一定的逻辑关系。通过对中学化学教学案例的统计归纳,发现一般存在2种逻辑关系,即一般知识逻辑和科学探究逻辑。这2种逻辑关系是连续性问题情境的类型。     

Characteristics of xenon-lamp pumped pyrromethene 567-doped dye laser based on polymethylmethacrylater

The solid-state medium containing pyrromethene 567 (PM567) in a polymethylmethacrylate polymer host is shown to lase under the flash lamp excitation. The experimental setup is an ordinary industrial product without special design. The bulk transmission losses, the output energy, and the other lasing properties are compared. The medium with the lowest transmission loss, measured to be 0.392 %/cm at 633 nm, gives a laser output of 130 mJ with a slope efficiency of 0.082%.     

高质量点集的快速局部网格生成算法

高效及高质量的局部网格生成算法是基于节点有限元并行方法设计的关键。泡泡布点算法能够在复杂区域上不经过人工干预生成高质量的节点集,本文提出了基于该方法所生成的节点集的快速局部网格生成算法。该算法充分利用泡泡布点方法提供的节点集及节点邻接链表信息,避免了桶数据结构的建立以及节点的局部搜索过程,只需应用Delaunay三角剖分的外接圆准则从中心节点的邻接链表中去除极少数的非卫星点,可快速地生成局部网格,比现有的局部网格生成算法更为快捷。算例结果表明,该算法高效可靠,生成网格与Delaunay三角剖分网格一致。     

《卫星通信》课程改革的探索与实践

结合《卫星通信》优质课程建设的具体实践,从教学内容调整、双语教学实践、教学方法以及教学手段的改进等方面进行了建设,授课实践表明改革取得了一定的成效,学生在理解卫星通信基本知识的同时,动手能力和英语水平也得到了提高.     

X荧光能谱分析中探测器响应函数建立方法

在X荧光能谱测量及分析过程中,通过建立探测器响应函数,可以实现对X荧光能谱中的全能峰峰形描述,有助于提高X荧光能谱分析速度、准确度和自动化程度。在X荧光能谱测量中,针对半导体探测器建立响应函数模型的理论与建模技术,文中对三种典型探测器响应函数建模方法,以及全能峰标准差、法诺因子等关键参数的求取进行了论述,并对已有研究进行了总结和比较。最后,对X荧光能谱测量中探测器响应函数建模方法给出了建议。     

基于金刚石色心自旋磁共振效应的微位移测量方法

基于压电陶瓷精密微位移系统的扫描探测技术是目前精密测量仪器进行微纳区域/结构性能测试的核心系统,但压电陶瓷材料存在迟滞、非线性问题,限制了对微位移分辨能力的提升.本文以金刚石氮空位色心为敏感单元,利用电子自旋效应对磁场强度的高分辨敏感机理,结合永磁体周围不同位置对应的磁场强度变化关系,提出了一种基于金刚石氮空位色心电子自旋敏感机理的微位移检测方法.通过建立电子自旋效应与微位移的关联模型,搭建了相应的微位移测量系统.经实验验证,该系统对微位移测试的灵敏度为16.67 V/mm,检测分辨率达到60 nm,实现了对微位移的高分辨率测量.并通过理论分析,该系统的微位移测量分辨率可进一步提升至亚纳米级水平,为新型微位移测量技术提供了发展方向和研究思路.     

基于光场调控的飞秒激光直写光波导研究进展(特邀)

飞秒激光直写是一种无掩模、高效、灵活的三维加工技术,可以对材料实现微纳米级加工,已经成为应用最广泛的材料精密加工技术之一.基于光波导的微纳光子器件(如分束器、频率转换器和电光调制器等),不但可以保持块体材料本身的优异特性,还能极大提高器件的性能和集成度,具有块体材料器件所不具备的特点和优势.因此,对集成光波导和光波导器...     

Plasma-assisted surface treatment for low-temperature annealed ohmic contact on AlGaN/GaN heterostructure field-effect transistors

In this study, a low-temperature annealed ohmic contact process was proposed on Al Ga N/Ga N heterostructure field effect transistors(HFETs) with the assistance of inductively coupled plasma(ICP) surface treatment. The effect of ICP treatment process on the 2DEG channel as well as the formation mechanism of the low annealing temperature ohmic contact was investigated. An appropriate residual Al Ga N thickness and a plasma-induced damage are considered to contribute to the low-temperature annealed ohmic contact. By using a single Al layer to replace the conventional Ti/Al stacks, ohmic contact with a contact resistance of 0.35 ?·mm was obtained when annealed at 575?C for 3 min. Good ohmic contact was also obtained by annealing at 500?C for 20 min.     

Single-shot grating-based x-ray differential phase contrast imaging with a modified analyzer grating

X-ray grating interferometer has attracted widely attention in the past years due to its capability in achieving x-ray phase contrast imaging with low brilliance source. However, the widely used phase stepping information extraction method reduces system stability and prolongs data acquisition time by several times compared with conventional x-ray absorptionbased imaging. The mechanical stepping can be avoided by using a staggered grating, but at the cost of low vertical spatial resolution. In this paper, employing a modified staggered grating and the angular signal radiography, we proposed a single-shot grating-based x-ray differential phase contrast imaging with decent vertical spatial resolution. The theoretical framework was deduced and proved by numerical experiments. Absorption, phase, and scattering computed tomography can be performed without phase stepping. Therefore, we believe this fast and highly stable imaging method with decent resolution would be widely applied in x-ray grating-based phase contrast imaging.