Acoustic characterization of AlN films using a High Overtone Bulk acoustic wave resonator

Abstract

Using the composite resonator with additional thick AlN film with the FWHM of rocking curve of 2.53° under investigation, the bulk acoustic wave attenuation constant and sound velocity along c-axis were directly measured. The method of High Overtone Bulk acoustic wave Resonator (HBAR) spectroscopy based on frequency, measurements of the positions of the resonator peculiarities of phase and amplitude of electromagnetic wave reflection coefficient from composite resonator structure was applied. The method provides attenuation and velocity measurement in a wide frequency band, using the same sample. For the measurements, standard and modified HBAR spectroscopy based on the analysis of only parallel resonance properties of composite resonator structures were used.     

上海光源XAFS光束线高次谐波抑制镜系统研制

讨论了上海光源(SSRF)XAFS光束线高次谐波抑制镜箱的研制.高次谐波抑制镜箱为XAFS实验提供高纯度光谱,主要机械结构包括镜子夹持机构、平移切换机构、三点调整机构.在机构设计中进行了分析与计算.根据测试获得的摇摆曲线对高次谐波抑制镜箱性能进行评估.     

Relating Complex Fluid Composition and Thermophysical Properties with the Advanced Distillation Curve Approach

Complex fluids have long posed a significant challenge in our ability to characterize and model fluid properties. Here, we consider complex fluids to be mixtures with many components that can differ significantly in polarity and polarizability. The penultimate complex fluid is crude oil, although many other fluids such as finished fuels are also highly complex. We have recently introduced a measurement strategy that can simplify these efforts and provides the added potential of linking chemical composition (i.e. analytical) information with physical property information. In addition to chemical characterization, the approach provides the ability to calculate thermodynamic and transport properties for such complex heterogeneous streams. The technique is based on the advanced distillation curve (ADC) metrology, which separates a complex fluid by distillation into fractions that are sampled, and for which thermodynamically consistent temperatures are measured at atmospheric pressure. The collected sample fractions can be analyzed by any method that is appropriate. Analytical methods we have applied include gas chromatography (with flame ionization, mass spectrometric and sulfur chemiluminescence detection), thin‐layer chromatography, FTIR, Karl Fischer coulombic titrimetry, refractometry, corrosivity analysis, neutron activation analysis and cold neutron prompt gamma activation analysis. We have applied this method on product streams such as finished fuels (gasoline, diesel fuels, aviation fuels, rocket propellants), crude oils (including a crude oil made from swine manure) and waste oil streams (used automotive and transformer oils). In this review, we describe the essential features of the ADC metrology with illustrative examples.     

某炮链条式弹簧平衡机设计计算

火炮在俯仰过程中，起落部分各部件对耳轴的重力力矩随射角变化产生的不平衡力矩会影响火炮传动系统的平稳性，从而降低火炮的射击精度。某型舰炮采用链条式弹簧平衡机，根据起落部分随射角变化的规律，通过最小二乘法拟合弹簧力学特性曲线，计算出弹簧的刚度系数与预压力。该机构结构紧凑，平衡效果明显，可为火炮总体设计和部件设计提供参考。     

均匀受压工字型等截面三铰圆弧钢拱的平面内稳定性和极限强度

采用大挠度弹塑性有限单元法对均匀受压等截面三铰圆弧钢拱的平面内稳定性和极限强度进行研究,考虑了材料非线性、残余应力、初始几何缺陷和矢跨比的影响,得到了均匀受压工字型等截面三铰圆弧钢拱的平面内稳定性设计曲线,并与国内外钢结构设计规范轴心受压构件的稳定曲线进行了对比,得出了轴心受压构件的稳定曲线不能直接用于拱的稳定性设计的重要结论。     

CAGD中可控曲线及其奇拐点分析

研究讨论了可控曲线的简单性质和奇点、拐点分析问题。它是采用苏步青教授提出的仿射不变量的理论,构造出可满足设计者所期望的具有某种奇拐点特性的曲线。     

20MnVBH钢CCT曲线的测定

用膨胀分析法测定了20MnVBH钢在1050℃和860℃连续冷却下的CCT曲线。并对转变后的试样进行了组织分析和硬度测定。结果发现:与马氏体区紧密相邻的宽阔的中间转变区域内存在粒状贝氏体组织;提高奥氏体化温度和加快冷却速度都有利于粒状贝氏体的形成。     

GRAPH-1图形教学软件

GRAPH-1是一个以演示为主的计算机图形教学辅助软件,它包括直线生成、自由曲线曲面、图形变换、立体描绘、动态显示、几何图案等和键盘绘图七个模块,形象地演示图形处理技术各部分理论所实现的功能。它使用高级语言编程,提供源程序和说明提示,在显示处理与用户界面处理等问题都有其独特的手段,本文将对GRAPH-1的结构与算法以及显示处理方面的内容作一介绍。     

热工对象模型阶次的一种数值分析方法

根据对象的输入输出采样数据，用数值计算方法分析热工对象模型的阶次。对于用曲线拟合方法建立热工对象的数学模型，本算法可以为模型阶次的确定提供依据。仿真例子表明，算法对无零点对象的分析结果是准确的。     

催化剂失活模型与机理探讨

综述了催化剂失活模型、失活机理以及失活速率表达式。重点介绍了催化剂中毒失活的平行、连串、并列和独立失活机理，提出了催化剂中毒活性曲线与活性关联式。