荧光分光光度法分析天然水中铝形态的研究

基于衍生试剂与天然水中原生有机质之间对铝的竞争配位,建立了用荧光分光光度法区分天然水中铝形态的方法。以铬蓝黑R和桑色素为分析试剂可以测定无机单核铝,而以8-羟基喹啉为分析试剂则可以测定总单核铝,实验结果与用Driscoll方法所得到的结果基本一致。为有目的地选择分析试剂,在天然水自身pH条件下进行铝形态的直接分析提供了一个新的方法选择。相对来说,荧光分光光度法操作更加简单,条件温和,对原始样品几乎没有扰动,天然水中铝形态分析的结果更符合真实情况。     

激光诱导击穿光谱分析钢中酸不溶铝含量

激光诱导击穿光谱(LIBS)具有分析速度快、非接触测量、表面微区分析以及易于实现在线实时监控分析等优点。通过LIBS对块状钢铁样品表面进行扫描分析,实现了钢中酸不溶铝含量的定量表征。铝的异常信号采用Nalimov迭代法剔除,以剩余信号强度的平均值加三倍标准偏差作为阈值强度,高于阈值强度的信号认为由酸不溶铝产生,反之由酸溶铝产生。在用含量校准曲线获得钢中总铝的含量后,分别根据酸不溶铝信号总强度或信号总个数与总铝信号之比,计算钢中酸不溶铝的含量。几种钢铁标准样品及实际生产板坯样品中酸不溶铝含量的对比分析结果表明,根据铝信号总强度获得的分析结果与传统湿法分析结果吻合得更好,可用于快速定量表征钢中酸不溶铝的含量。     

氦泡铝的层裂特性实验研究

含氦泡材料的动态断裂性能是多个研究领域关注的重点。采用平板冲击实验技术,对含有氦泡、硼等杂质的铝材料进行了层裂实验研究,由双光源混频系统分别测量了纯铝、掺硼铝以及两种氦浓度的含氦泡铝样品的自由面速度,对比分析了不同杂质影响下铝材料的层裂强度及其差异。实验显示:纯铝的层裂强度为1.28 GPa,引入硼杂质使铝的层裂强度显著降低,降低幅度接近50%;中子辐照掺硼铝引入氦泡后,对铝的层裂性能没有造成进一步影响,说明采用中子辐照掺硼铝方法制备含氦泡铝时,氦泡效应不显著,即氦泡对材料的动态断裂性能影响有限。此外,根据实验测量结果,简要讨论了硼和氦泡等对铝的Hugoniot弹性极限的影响。     

ICP-AES同时测定新型复合脱氧剂硅铝钙钡合金中的铝和钙

ICP-AES测定新型复合脱氧剂硅铝钙钡合金中的铝和钙,对共存元素、仪器分析参数等因素进行了研究,确定了仪器的最佳分析条件,建立了一种可同时测定铝和钙含量的简单、快速的分析方法,其测定结果与滴定分析方法的测定值一致,完全能满足生产和科研的需要。     

人工神经网络直读光谱法测定钢中酸溶铝

用火花直读光谱法测定钢中不同状态的铝是目前研究的热点之一。本文确立了直读光谱法的分析条件,将人工神经网络用于直读光谱法,用直读光谱的全铝光谱强度值作为网络的输入,标样中的酸溶铝值作为期望值,建立神经网络模型,用神经网络直读光谱法测定中低合金钢中酸溶铝含量,分析结果的准确度与化学分析法基本一致。神经网络使用改进的BP算法,避免了学习过程可能产生的麻痹现象,提出了目标向量的简单变换方法。该法用于钢中酸溶铝的直接测定,获得满意结果。     

去除铝基板的大功率LED热分析

提出一种大功率LED免铝基板封装方式,采用ANSYS有限元热分析软件对传统的铝基板封装和免铝基板封装的LED进行模拟对比分析。模拟结果表明:两种封装结构的LED,其最高温度均出现在LED芯片处;对于单颗功率1 W、3颗功率1 W和单颗功率3 W的器件,由于有效地简化了散热通道、大幅度降低了总热阻,采用免铝基板结构的最高温度分别降低了6.436,9.468,19.309 ℃。传统的铝基板封装即使选用热导率高达200 W/(m·K)的基板,其散热效果依旧略逊于免铝基板封装结构,且随着LED功率的增大,免铝基板的新型封装结构散热优势更加明显。本文的研究为解决大功率LED的散热问题和光色稳定性问题提供了一种新途径。     

峰值积分法分析铝的研究与应用

在直读光谱仪上,用峰值积分法测定低合金钢中铝,酸溶铝和酸不溶铝的含量,确定最佳分析条件,研究峰值积分法的分析机理,本方法用于测定低中不同状态铝,结果符合要求.     

高压热处理对铝青铜热物理性能的影响

在5 GPa压力下对铝青铜进行750℃、保温15 min的高压热处理,对高压热处理前后铝青铜的电导率以及25～600℃温度范围内的热扩散系数、热容和热导率进行测试,结合显微组织的观察结果,探讨了高压热处理对铝青铜热物理性能的影响。研究表明:高压热处理能增大铝青铜的热扩散系数,减小热容;对热导率而言,温度低于400℃时高压热处理能增大铝青铜的热导率,而温度高于400℃时高压热处理能减小铝青铜的热导率。分析认为,产生变化的主要原因是高压热处理使铝青铜的微观组织发生了变化。     

铝的光度分析简介

介绍了光度法分析铝的一些方法；讨论了显色时干扰物质及其消除；比较了测定铝的显色剂。     

含泡沫铝防护结构的超高速撞击数值模拟研究

 泡沫铝是一种新型航天器防护材料,拥有良好的抵御空间碎片超高速撞击的特性。模仿泡沫金属的生产原理,建立了泡沫金属微结构几何模型,结合自编的光滑质点流体动力学程序进行了超高速撞击数值仿真,通过与实验结果的对比,验证了模型的有效性。提出了两种含泡沫铝的空间碎片防护结构,即填充泡沫铝结构和夹层泡沫铝结构。对这两种结构分别进行了仿真计算,获得了其撞击极限曲线。分析结果表明,在空间碎片防护领域涉及的大部分撞击速度区间内,填充泡沫铝结构的防护性能优于夹层泡沫铝结构。     

可变形弹丸贯穿铝合金靶的数值模拟

 采用显式动态有限元商业软件ABAQUS/Explicit对可变形卵形弹丸正贯穿和斜贯穿有限厚度铝合金靶的过程进行了有限元数值模拟。根据空穴膨胀理论,将靶体对侵彻的影响用一个作用在弹体表面的力函数代替,同时考虑了有限厚度靶自由表面的影响,并对空穴膨胀得到的力函数进行了修正。这样在进行数值模拟时就无需对靶体划分网格,也避免了复杂的接触问题,从而使模拟大为简化。最后,用VAR4340钢弹贯穿6061-T651铝合金靶板得到的数值模拟结果与实验结果进行了比较,二者基本吻合。     

Modification of galvannealed steel through aluminum addition

Aluminum is believed to modify and to some extent control the coating characteristics of commercially produced galvanneal sheet steel. These include mechanical, chemical, and aesthetic properties. Whereas the aluminum added to the molten zinc bath is known to form intermetallics before the steel is annealed, our research is primarily concerned with the effect aluminum has on suppression or enhancement of the particular iron--zinc alloy phases in the coating during galvannealing. The microstructure of four commercially important iron--zinc intermetallic phases containing varying aluminum content between 0--1.5 weight percent has been studied. It is also believed that an iron--aluminum alloy, known as the inhibition layer, forms on the steel surface following hot dipping and prior to annealing. Transmission and scattering Mössbauer spectroscopy as well as X-ray diffraction have been used to identify iron--zinc and iron--aluminum alloys present in the coatings. Discussion will be presented on the effect aluminum has on phase suppression for Fe--Zn alloys prepared in commercially produced galvanneal.     

X-ray diffraction analysis of double-layer systems irradiated by a high-power ion beam

Systems of thin Ni films on a copper substrate, thin Ni films on an aluminum substrate, and St20 steel covered with graphite irradiated by a high-power ion beam of nanosecond duration have been investigated by x-ray diffractometry. The mixing of nickel with aluminum and St20 steel with graphite is revealed. It is shown that the mixing predominantly occurs in the liquid phase and depends on the thermal properties of a film and substrate.     

Fabrication of superhydrophobic surfaces on engineering material surfaces with stearic acid

Via a simple wet chemical etching followed by stearic acid modification, the presence of synergistic binary structures at micro- and nanometer scales and stearic acid bestows superhydrophobic property on steel and aluminum alloy surfaces. The as-prepared surfaces show superhydrophobic not only for pure water but also for corrosive liquids such as acid, basic and salt solutions. The stable superhydrophobicity of steel and aluminum alloy surfaces will extend their applications as engineering materials.     

ICP-AES测定彩涂镀铝锌板镀层中铝的含量

本文着重研究了样品前处理和用电感耦合等离子体-原子发射光谱仪测定彩涂镀铝锌板镀层中Al含量的最佳方法，测定结果表明，方法的回收率和精密度分别为99．8％和1．13％，该方法快速、准确、可靠，适用于彩涂板镀层中铝含量的日常检验。     

Effect of cathode material on the opening performance ofmicrosecond-conduction-time plasma opening switch

Experiments were conducted to investigate the effect of cathode material on the opening performance of microsecond-conduction-time plasma opening switch with cathode made of aluminum, stainless steel, molybdenum and tungsten. Remarkably different opening characteristics have been shown for these materials, with tungsten or molybdenum corresponding to better opening performance than aluminum or stainless steel. Heuristic physical explanations are proposed for understanding the switch behavior     

基于光纤光栅的冲击激励声发射响应机理与定位方法研究

在对冲击激励声发射应力波在铝合金板上的传播机理进行分析的基础上,利用ABAQUS软件构建了钢球冲击铝合金板几何模型,仿真分析了冲击应力波传播过程.理论分析了冲击应力波与FBG传感器的作用机理,基于边缘滤波原理构建了声发射传感系统,采集冲击激励声发射应力波,建立了声发射区域定位模型,提出了基于扩散映射与支持向量机(SVM)的声发射区域定位方法并进行了实验验证.在300 mm×300 mm×2 mm的铝合金板上对36个测试区域进行了多次声发射区域定位实验,实验结果表明,扩散映射结合SVM的定位结果较优,区域定位精度为30 mm×30 mm,定位正确率为97.5%,耗时0.781 s.研究结果为声发射区域定位检测提供了一种有效方法.     

Results from the irradiation of stainless steel and copper by 23 MeV γ-quanta in the atmosphere of molecular deuterium at a pressure of 2 kbar

Metal samples were arranged inside a “finger-type” high-pressure chamber (DHPC-FT) filled by deuterium. They were two aluminum rods, a copper rod, two specimens of homogeneous YMn₂ alloy, and a stainless steel wire. The pressure of molecular deuterium in DHPC-FT was about 2 kbar. The samples were irradiated by braking γ-quanta at a threshold energy of 23 MeV. All the samples were studied using scanning electron microscopy (SEM) and X-ray (roentgen) microelement probe analysis (RMPA). Considerable changes in the surface structure and elemental composition were found for the samples of copper, aluminum, YMn₂ alloy, and stainless steel. Unusual results were analyzed in detail and compared with the earlier data.