An Efficiency Enhanced Graphene/n-Si Schottky Junction for Solar Cells

A novel and facile oxidation-induced self-doping process of graphene-silicon Schottky junction by nitric acid(HNO_3) vapor is reported. The HNO_3 oxidation process makes graphene p-type self-doped, and leads to a higher built-in potential and conductivity to enhance charge transfer and to suppress charge carrier recombination at the graphene-silicon Schottky junction. After the HNO_3 oxidation process, the open-circuit voltage is increased from the initial value of 0.36 V to the maximum value of 0.47 V, the short-circuit current is greatly increased from 0.80μA to 7.71μA, and the ideality factor is optimized from 4.4 to 1.0. The enhancement of the performance of graphene-Si solar cells may be due to oxidation-induced p-type self-doping of graphene-Si junctions.     

以四乙基氢氧化铵为模板并通过转晶法合成高硅铝比的SSZ⁃13沸石分子筛

使用四乙基氢氧化铵为有机模板剂,以低硅铝比(nSiO2/nAl2O3)的Y分子筛为铝源,通过转晶法制备结晶度良好的SSZ?13沸石分子筛。从凝胶配比方面考察了不同原料组成对分子筛合成的影响,并通过X射线衍射(XRD)、扫描电子显微镜(SEM)及电感耦合等离子体(ICP)表征水热反应过程中的物相、形貌、硅铝比等变化,揭示分子筛合成过程。氨选择性催化还原(NH3?SCR)反应显示该分子筛具有优异的催化活性,为其工业上的广泛应用提供了可能性。     

车轮多边形激励下高速列车制动界面摩擦学行为分析

高速列车车轮多边形磨耗是一种沿车轮周向的不均匀磨耗,是列车服役过程中常见的车轮失效现象,其产生的剧烈轮轨激励严重威胁车辆系统服役可靠性. 制动系统作为保障高速列车服役安全的核心部件,其界面摩擦学行为直接受到轮轨激励的影响. 为探究车轮多边形激励下的制动界面摩擦学行为,建立了刚柔耦合车辆动力学模型和制动系统热机耦合有限元模型,并分别通过线路试验和台架试验验证了模型的正确性. 然后,提出一种考虑车轮多边形激励的制动界面摩擦学行为分析方法,能够真实地反映服役过程中制动界面摩擦学行为. 基于此,研究了不同车辆运行速度下车轮多边形激励对制动系统动态接触、温度以及振动特性的影响规律. 结果表明:车轮多边形磨耗导致系统接触面积、摩擦热、接触应力和振动等摩擦学行为更为复杂且剧烈. 此外,系统接触面积标准差和振动加速度均方根值随速度的增加而增大. 因此,车轮多边形磨耗对制动界面摩擦学行为具有不可忽略的影响. 该研究成果可为制动系统界面摩擦学行为研究及结构优化设计提供有效方法与工程指导.      

电磁内爆模拟技术实验研究进展

开展了中俄Z—pinch联合实验和强光一号实验，重点对双层丝阵内爆动力学模式、单层丝阵填充泡沫构建动力学黑腔及能谱相对强度的测量等进行了研究，取得了一批重要的物理研究成果。实现了双层丝阵内外层等离子体的同时内爆聚心，产生5．6TW的峰值辐射功率，     

Effect of the stoichiometry on the electronic structure of the Ni（111）/α-Al2O3（0001） interface： a first-principles investigation

In this paper first-principles calculations of Ni（111）/α-Al2O3（0001） interfaces have been performed, and are compared with the preceding results of the Cu （111）/α-Al2O3（0001） interface [2004 Phil. Mag. Left. 84 425]. The AI- terminated and O-terminated interfaces have quite different adhesion mechanisms, which are similar to the Cu（111）/α Al2O3（0001） interface. For the O-terminated interface, the adhesion is caused by the strong O-2p/Ni-3d orbital hybridization and ionic interactions. On the other hand, the adhesion nature of the Al-terminated interface is the image-like electrostatic and Ni-Al hybridization interactions, the latter is substantial and cannot be neglected. Charge transfer occurs from Al2O3 to Ni, which is opposite to that in the O=terminated interface. The charge transfer direction for the Al-terminated and O-terminated Ni（111）/α-A1203（0001） interfaces is similar to that in the corresponding Cu（111）/α- Al2O3（0001） interface, but there exist the larger charge transfer quantity and consequent stronger adhesion nature, respectively.     

有理二次B—样条曲线的权系数与交比问题

对于控制顶点相同的两条有理二次Ｂ－样条曲线，本文证明了从任一控制顶点引出的射线上给定四点的交比值与射线位置无关的充要条件。对于一条有理二次Ｂ－样条曲线，本文还给出了另一种四个共线点的交比表示，此交比仅与过此顶点的射线位置有关，而与曲线的权系数无关，还给出了此交比在一定意义下为射影不变量的充要条件。     

数学知識在农村大有用途

下乡劳动之前,认为学农的学医的同志在农村可以结合专业,而学数学的则难以与专业结合。通过与贫下中农九个多月的接触和参加农田劳动的实践,使我深深地感到,数学与其他学科一样,在当前农村的大好形势里,不仅能够结合上而且是大有用途,充分体现了数学是生产斗争知识。 (一) 贫下中农迫切需要数学知识当贫下中农知道我是学数学的且会点珠算时,立即要求我教会他们珠算,每晚参加学习的有男女青年还有四、五十岁的老大伯。他们虽然白天劳动一天,体     

储存环高频剔除系统

 介绍了用于电子储存环部分填充和非均匀填充的一种实验装置,它利用储存环中电子运动所具有的横向自由振荡和束团脉冲的时间结构这一特性,采用外加激励的方法使其产生共振,从而使得储存环中部分束团中的电子丢失,形成储存环的部分填充和非均匀填充。还扼要介绍了用高频剔除系统在储存环上实现不同填充方式时的束流积累结果。     

双重演示效果"固体热胀冷缩演示仪" 设计与实践

介绍一款双重演示效果"固体热胀冷缩演示仪",该仪器在演示效果的显著程度和综合性知识含量两方面较现有演示仪有实质性突破.     

Manipulation of Particles with Counter-Propagating Evanescent Waves

Two counter-propagating evanescent beams are used to align and manipulate polystyrene particles on a prism surface. Since the radiation pressure transferred laterally from the evanescent wave is negated on both sides, particles can be stably aligned. By projecting a circular and a linear beam spot onto the interface, both multiple and single arrays of particles are achieved. Arrays of particles trapped on the interface can be easily moved adjusting the intensity of incident beams on either side. We also simulate electromagnetic distribution of scattering light that is converted from the evanescent wave using the FDTD method. The results show that scattering light converts from an evanescent wave propagating through a particle array and has a distance longer than that propagating from a normal evanescent wave.