脉冲激光沉积制备c轴取向AlN薄膜

ｃ轴取的ＡｌＮ具有优异的压电性和声表面波传输特性,已受到人们日益广泛的重视。文章报道了采用ＫｒＦ脉冲准分子激光沉积工艺,在Ｓｉ（１００）衬底上成功地制备了ｃ轴取向的ＡｌＮ晶态薄膜。Ｘ射拇衍射与傅里叶变换红外光谱的结果表明,在３００℃－８００℃衬底温度下,薄膜均只有（００２）－一个衍射峰,但随着温度的升高,薄膜的结晶质量变好;     

基于TextRank算法的联合打分文本摘要生成

自动文本摘要生成是自然语言处理领域中颇具挑战性的问题之一,其任务是为书籍、篇章、新闻或者微博等某一文本资源生成简洁而又具有意义的文本摘要.TextRank算法是一种基于图的文本摘要生成算法,只利用当前文档即可实现关键词提取和文摘生成,因其简洁有效而得到广泛应用.本文在TextRank算法的基础上提出一个无监督抽取式联合...     

〈111〉晶向冲击加载下单晶铜中纳米孔洞增长的早期动力学行为

利用分子动力学方法模拟计算了单晶铜中纳米孔洞在沿〈111〉晶向冲击加载下增长的早期过程.测量发现不同加载强度下等效孔洞半径随时间近似成线性变化.观测到单孔洞增长的两种位错生长机理：加载强度较低时，只在沿着冲击加载方向的孔洞顶点附近区域有位错的成核和运动；而随着加载强度超过一定阈值，在沿冲击加载和其垂直方向的孔洞顶点区域都观察到位错的成核和运动.在前一种机理作用下，孔洞只沿加载方向增长；在后一种机理作用下，孔洞同时沿加载和垂直于加载方向增长.分析孔洞表面原子的位移历史，发现沿加载及与其垂直方向的孔洞顶点沿径向的速度基本恒定，由此提出了一个孔洞生长模型，可以解释孔洞增长的线性生长规律. 关键词： 纳米孔洞 分子动力学 冲击加载 位错     

The degradation mechanism of an AlGaN/GaN high electron mobility transistor under step-stress

Step-stress experiments are performed in this paper to investigate the degradation mechanism of an AlGaN/GaN high electron mobility transistor(HEMT).It is found that the stress current shows a recoverable decrease during each voltage step and there is a critical voltage beyond which the stress current starts to increase sharply in our experiments.We postulate that defects may be randomly induced within the AlGaN barrier by the high electric field during each voltage step.But once the critical voltage is reached,the trap concentration will increase sharply due to the inverse piezoelectric effect.A leakage path may be introduced by excessive defect,and this may result in the permanent degradation of the AlGaN/GaN HEMT.     

基于 RLWE 的全同态加密方案简

基于Kristin Lauter等人的somewhat同态方案,提出“带密钥转换的重线性化技术”。结合该技术与“模转换”,设计了一个基于RLWE的非自举的层次化全同态加密方案。该方案的同态操作简单,而且给出的平凡门操作使得电路层结构更清晰。最后利用自举技术作为优化提升了方案的同态运算能力。     

Efficient and stable wireless power transfer based on the non-Hermitian physics

As one of the most attractive non-radiative power transfer mechanisms without cables,efficient magnetic resonance wireless power transfer(WPT)in the near field has been extensively developed in recent years,and promoted a variety of practical applications,such as mobile phones,medical implant devices and electric vehicles.However,the physical mechanism behind some key limitations of the resonance WPT,such as frequency splitting and size-dependent efficiency,is not very clear under the widely used circuit model.Here,we review the recently developed efficient and stable resonance WPT based on non-Hermitian physics,which starts from a completely different avenue(utilizing loss and gain)to introduce novel functionalities to the resonance WPT.From the perspective of non-Hermitian photonics,the coherent and incoherent effects compete and coexist in the WPT system,and the weak stable of energy transfer mainly comes from the broken phase associated with the phase transition of parity-time symmetry.Based on this basic physical framework,some optimization schemes are proposed,including using nonlinear effect,using bound states in the continuum,or resorting to the system with high-order parity-time symmetry.Moreover,the combination of non-Hermitian physics and topological photonics in multi-coil system also provides a versatile platform for long-range robust WPT with topological protection.Therefore,the non-Hermitian physics can not only exactly predict the main results of current WPT systems,but also provide new ways to solve the difficulties of previous designs.     

新型低阈值高效激光晶体Nd：SVAP的研究

研究的新型激光晶体Ｎｄ：Ｓｒ５（ＶＯ４）３Ｆ的生长，物理化学性能，光谱与激光性能，报道了激光二极管泵浦的Ｎｄ：Ｓｒ５（ＶＯ４）３Ｆ基频及腔内倍频激光器的研究结果。     

网格安全分析及安全措施

网格是网络发展的必然趋势,网格环境的特殊性使得网格安全成为制约网格应用的焦点。论文主要分析了网格环境下的安全问题,提出了网格的安全目标,介绍了GIG安全措施、网格信任一体化安全机制,并展望了网格安全的后续发展。     

分层小区技术在GSM网络中的应用

从分层小区技术（HCS）基本概念出发，对HCS技术在容量和覆盖方面的应用进行由浅入深的分析和研究，为移动运营商在GSM网络中引入HCS技术提供有益的参考。     

2MeV有箔注入器的束流调试

为２０ＭｅＶ ＬＩＡ建造的２ＭｅＶ注入器的束流技术指标经过一年多实验调试已达到能量２ＭｅＶ、束流３ｋＡ、亮度大于或等于１０＾８Ａ／（ｍ．ｒａｄ）＾２。建立了二维数字模型，对注入器的电子发射和束流传输过程进行了模拟，用模拟结果指导实验调试，并同实验结果进行对照，重点分析了有箔情况下自有的聚焦作用。