仪器分析试验的正交设计

对一名分析化学工作者来说，在工作中经常遇到这样的问题，如用原子荧光光谱仪测定水或矿物中的铅时，发现灯电流、光电倍增管、负高压、载气(氩气)流量、观测高度和温度、硼氢化钾浓度、盐酸和铁氰化钾、草酸混合溶液浓度等都对测定灵敏度有影响，因此用最简单的方法，最少的检测次     

熔融石英晶化抑制与烧结性能

以〈0．040mm的熔融石英粉体为原料,以五氧化二磷、氧化钛、氧化铝、硼酸、氮化硅为添加剂,试样成型压强为50MPa,试样经1200℃、1300℃、1400℃、1500℃分别保温1小时烧成,对烧后试样进行抗折强度、气孔率、热膨胀率、XRD、SEM的测定,研究添加剂种类与含量对熔融石英晶化与烧结性能的影响。试验结果表明：对于1300℃烧结后的试样,添加剂氧化铝、氮化硅的引入对熔融石英的晶化具有明显的抑制作用。引入氧化钛、氮化硅的熔融石英试样的抗折强度较高,具有较好的烧结性能。引入五氧化二磷的试样烧结程度差,该添加剂具有促进熔融石英晶化的作用。     

纳米尺度上表面物理学的研究进展

简述了表面物理学的发展历程与当前研究热点,并对当前人们所采用的一些先进的表面分析方法进行了介绍.通过对表面物理研究领域中重要研究对象--半导体表面上生长低维有序金属纳米结构的形成与机理的研究表明,在纳米尺度上的表面科学将会给整个人类带来新的技术革命.     

采煤工作面高抽巷与回风巷合理内错距离确定研究

实践中发现,采煤工作面高抽巷与回风巷内错距离对采场瓦斯治理效果有明显的影响,为提高高抽巷瓦斯抽采效果,对确定两者合理内错距离进行了研究。首先,基于Brinkman、N-S、平移-扩散方程和Fick扩散定理结合采场气体的流动特征,建立了采煤工作面瓦斯流动耦合模型。然后,以某矿11210工作面为例,采用COMSOL Multiphysics多物理场耦合分析软件模拟不同内错距离情况下采场瓦斯浓度及流场分布特征,并结合生产实践进行了验证。结果表明:上隅角和采空区上部平均瓦斯浓度与内错距离呈"V"型关系,当内错距离约30 m时,平均瓦斯浓度最小,瓦斯治理效果最好。数值模拟分析结果与生产实践应用结果基本一致,说明确定的内错距离较合理。     

Corrugated single layer templates for molecules: From <Emphasis Type="Italic">h</Emphasis>-BN nanomesh to graphene based quantum dot arrays

Functional nano-templates enable self-assembly of otherwise impossible arrangements of molecules. A particular class of such templates is that of sp ² hybridized single layers of hexagonal boron nitride or carbon (graphene) on metal supports. If the substrate and the single layer have a lattice mismatch, superstructures are formed. On substrates like rhodium or ruthenium these superstructures have unit cells with ～3-nm lattice constant. They are corrugated and contain sub-units, which behave like traps for molecules or quantum dots, which are small enough to become operational at room temperature. For graphene on Rh(111) we emphasize a new structural element of small extra hills within the corrugation landscape. For the case of molecules like water it is shown that new phases assemble on such templates, and that they can be used as “nano-laboratories” where many individual processes are studied in parallel. Furthermore, it is shown that the h-BN/Rh(111) nanomesh displays a strong scanning tunneling microscopy-induced luminescence contrast within the 3 nm unit cell which is a way to address trapped molecules and/or quantum dots.     

高职"ASP.NET程序设计实训"课程教学改革探索

分析了高职＂ASP.NET程序设计实训＂课程的教学现状,总结了传统实训教学中存在的问题。以注重学生能力层次结构为出发点,提出了＂项目分层选择＂的实训项目设计思想、＂任务分层驱动＂的实训教学设计思想以及＂能力分层考核＂的实训考核设计思想,从实训项目设计、实训教学设计、实训考核设计三个方面对＂ASP.NET程序设计实训＂课程的教学改革进行探索和实践。     

宇宙及其图像的历史素描

 仰望星空,我们在感觉到自身渺小的同时,往往会情不自禁地遐想浩淼宇宙的本源。宇宙究竟是什么样子,它的过去与未来是何种光景?古往今来,不但文学作品中常常出现大胆的想象,而且很多科学家也乐此不疲。尽管如此,人们对宇宙及其相关理论仍只停留在常识层面。究其原因,无非是理论艰涩及人生短暂,往往使人望而却步。因而,对于宇宙及其复杂理论的探索,只有极少数学识超常且毅力非凡者才能进行,而在这些科学巨匠中,能够将复杂理论以通俗方式表述且引人入胜者,更是少之又少。但英国物理学家史蒂芬·霍金(S.W.Hawking,1942—)就是其中之一。     

Corrugated single layer templates for molecules: From h-BN nanomesh to graphene based quantum dot arrays

Functional nano-templates enable self-assembly of otherwise impossible arrangements of molecules. A particular class of such templates is that of sp² hybridized single layers of hexagonal boron nitride or carbon (graphene) on metal supports. If the substrate and the single layer have a lattice mismatch, superstructures are formed. On substrates like rhodium or ruthenium these superstructures have unit cells with ~3-nm lattice constant. They are corrugated and contain sub-units, which behave like traps for molecules or quantum dots, which are small enough to become operational at room temperature. For graphene on Rh(111) we emphasize a new structural element of small extra hills within the corrugation landscape. For the case of molecules like water it is shown that new phases assemble on such templates, and that they can be used as “nano-laboratories” where many individual processes are studied in parallel. Furthermore, it is shown that the h-BN/Rh(111) nanomesh displays a strong scanning tunneling microscopy-induced luminescence contrast within the 3 nm unit cell which is a way to address trapped molecules and/or quantum dots.     

Formation and local electronic structure of Ge clusters on Si（111）-7×7 surfaces

We report the formation and local electronic structure of Ge clusters on the Si(111)-7$\times $7 surface studied by using variable temperature scanning tunnelling microscopy (VT-STM) and low-temperature scanning tunnelling spectroscopy (STS). Atom-resolved STM images reveal that the Ge atoms are prone to forming clusters with 1.0~nm in diameter for coverage up to 0.12~ML. Such Ge clusters preferentially nucleate at the centre of the faulted-half unit cells, leading to the `dark sites' of Si centre adatoms from the surrounding three unfaulted-half unit cells in filled-state images. Bias-dependent STM images show the charge transfer from the neighbouring Si adatoms to Ge clusters. Low-temperature STS of the Ge clusters reveals that there is a band gap on the Ge cluster and the large voltage threshold is about 0.9~V.