Influence of background pressure on the microstructure and optical properties of Mo/Si multilayers fabricated by magnetron sputtering

Mo/Si multilayers were fabricated by using magnetron sputtering method at different background pressures:6×10-5 Torr,3×10-5 Torr,and 3×10-6 Torr.The reflectivity of the Mo/Si multilayers increased from 1.93% to 16.63%,and the center wavelength revealed a blue shift to 0.12 nm with the decrease of background pressure.Grazing incident X-ray diffraction(GIXRD) indicated that multilayers fabricated at high background pressure possessed better periodic structure and thinner Mo-on-Si interlayers.Low crystallization degree in(110) preferred the orientation of Mo layers and serious interdiffusion in the Mo/Si multilayers fabricated at low background pressure were observed by transmission electron microscopy(TEM).According to quantitative analysis of microstructural parameters,the Mo layers thickness and thickness ratio of Mo/Si multilayers both decreased and approached the design value gradually by the decrease of background pressure.In addition,the thicknesses of Mo-on-Si and Si-on-Mo interlayers were 1.17 nm and 0.85 nm respectively.It is suggested that the influence of background pressures on the microstructure has a critical role in determining the optical properties of Mo/Si multilayers.     

海上丝绸之路关键海峡/运河安全效率研究

海峡/运河是海上丝绸之路的重要节点,其安全性决定海上丝绸之路能否正常运行,因而研究海峡/运河的安全性至关重要。本文通过改进松弛变量度量模型(SBM),构造了基于非期望要素的SBM集成性排序方法,揭示了海峡/运河安全效率的完全排序;根据删除某指标不影响效率排序则应剔除该指标的思路,筛选最优评价指标体系;通过计算某指标对决策单元效率的影响程度,确定海峡/运河安全效率关键影响因素。实证结果表明,马六甲海峡安全效率较高,而曼德海峡安全效率较低,其余四个海峡/运河效率居中,且相差不大;海盗和船舶事故是影响安全效率的重要因素。     

Global modeling 2~(nd)-order ionospheric delay and its effects on GNSS precise positioning

Ionospheric delay is one of the major error sources in GNSS navigation and positioning.Nowadays,the dual-frequency technique is the most widely used in ionospheric refraction correction.However,dual-frequency measurements can only eliminate the first-order term of ionospheric delay,while the effect of the second-order term on GNSS observations may be several centimeters.In this paper,two models,the International Reference Ionosphere (IRI) 2007 and International Geomagnetic Reference Field (IGRF) 11 are used...     

基于层次分析法的几种家用汽车购车模型

目前,随着我国人民生活水平的不断提高,家庭购车逐渐成为一种新的需求.但面对纷繁多变的汽车市场,很多消费者苦于车型的抉择.为了解决家庭购车中的科学决策问题,根据来自汽车销售市场的实际信息,以目前几种10万元以下的主流家用轿车为研究对象,应用层次分析法得到购买家用汽车的数学模型,从而使定量化地解决了车型抉择问题.     

Topographies of Organized Monolayer of α-Amylase Observed by Atomic Force Microscopy

Preparing the organized ultrathin film of proteins is the key to developing of protein-based molecular devices such as biosensors. In the past, the organized molecular layers were fabricated by the means of Langmuir-Blodgett (LB), which utilized the amphipathy of molecules. Molecular deposition (MD) which is based on the electrostatic interaction between the charged substrates and oppositely charged absorbate is a new and versatile method for preparing organized self-assembled ultrathin film…     

自回归模型建立的必要条件及其应用

给出了对时间序列资料选择建立7种自回归模型的必要条件,并结合实际例子进行了分析和阐述.     

基于改进的共沉淀法处理含钚废水的实验研究

采用共沉淀的方法，通过改变原始的工艺条件，对含钚废水进行了大量的序批式实验。实验数据表明，KMnO₄、含铁试剂以及NaOH 加入的顺序对钚的吸附影响颇为显著，以先加KMnO₄、调节酸碱值(pH)和加入吸附剂的顺序进行实验时对钚的吸附效果最佳。在pH≈10 时，FeCl₃ 和FeCl₂ 的混合试剂比FeSO₄ 和Fe₂(SO₄)₃ 的混合试剂以及FeSO₄ 试剂吸附沉降钚的能力强、速率快，且FeCl₃ 和FeCl₂ 的比例不同，对钚的沉降效果也有影响。经测定，改进后的工艺对带放射性的废水中钚的沉降能力可以提升20%，而沉降所需时间缩短至原来的1/5。     

芯动时刻——基于微流控芯片的科普实验方案*

依托微流控芯片高效、低耗、微尺度等优势,在微通道体系中设计演示酸碱中和、配位、氧化还原等经典实验。通过微尺度下的多相层流、界面反应和径向扩散等效应,建立以界面扩散为主导的演示实验,全过程以慢镜头的谱带方式展现出来,令反应直观易懂,该实验操作简单,并兼具多学科知识交叉。在本设计教学应用中,针对高中生、本科生和专科生知识背景差异,可在普通实验条件下分级进行,对不同层次的学生进行针对性训练,实验操作难度低、试剂用量少(数毫升)、时间短(数分钟)、场地小,兼顾绿色与安全,适合在各本专科院校及中学的实验教学中普及开展。     

钴基非晶丝发动机转速测量仪

基于钴基非晶丝优异的巨磁阻抗特性,采用STM32F407单片机为信号处理和控制系统,设计了发动机转速测量仪。主要包括钴基非晶丝探头,多谐振荡电路,放大电路,电源电路和液晶显示。运行试验表明,仪器结构简单,工作可靠稳定。