Kinetics of emitted mass—A study with three dry powder inhaler devices

The purpose of this study was to understand the kinetics of emptying of micronised salbutamol sulphate (SS) and lactohale 300 (LH300) under varying air flow rates (30–180 L min⁻¹) from three dry powder inhaler devices, Rotahaler^® (RH), Monodose Inhaler^® (MI) and Handihaler^® (HH). Aerosol concentration vs. time profiles, determined through real-time laser diffraction particle sizing, demonstrated that the majority of the powder from RH was emitted within one second while a more prolonged aerosolisation was observed from MI and HH. Peak aerosol concentrations were achieved more rapidly from RH compared to MI for both SS and LH300. Calculated cumulative emitted mass (CCEM) vs. time profiles were obtained from the aerosol concentration vs. time profiles and the emitted mass and the rate of CCEM (k_CCEM), estimated from a modelling approach, increased with increasing air flow rates. The k_CCEMvs. air flow rate profiles of SS and LH300 were significantly different at high air flow rates. The k_CCEM was highest from RH and lowest from MI. Differences in k_CCEM between the devices were related to capsule aperture size while the differences between the materials were due to the powder bed structure. This approach provided an understanding of the rate at which powder mass emptied from dry powder inhaler devices and was proposed to be a powerful development tool for the future powder inhalers.     

光亮酸性镀铜的设备配置

电镀设备设施的完善和改进,往往能比单纯从对工艺镀液的调整、处理获得更好的效果。硫酸盐光亮酸性镀铜,由于工艺的某些特殊性,对此要求更高。本文结合不同体系光亮剂的工艺特点,进行了较为详细的讨论。连续过滤、镀液搅拌、液温过低时的恒温电加热、采用低纹波直流电源,是共同需要的;当液温超过工艺上限时,应根据多种因素来选择不同的降温措施。即使对宣称可不除膜的工艺,在工艺布局设计时,也宜设简单的化学除膜工序,以备不时之需。     

Design of Computer Experiments for Metamodel Generation

We review the use of statistical design and analysis of computer experiments (DACE) for the generation of parsimonious, surrogate models, also known as metamodels. Such metamodels are used to replace cpu- or memory-intensive, discretized approximations that often arise in MEMS and MOEMS. Emphasis is placed on optimal designs.     

a-C:F:H films prepared by PECVD

Fluorinated amorphous hydrogenated a-C:F:H carbon thin films were deposited using radio frequency plasma enhanced chemical vapor deposition(RF-PECVD) reactor with CF4 and CH4 as source gases and were annealed in a N2 atmosphere. The properties of these films were evaluated by FTIR spectrometry, UV-VIS spectrophotometry and single-wavelength spectroscopic ellipsometry. A correspondence relativity connection between the deposition rate and technology was found. The chemical bonding structures and the content of CHx and CFx in the films are transformed and the optical band gap decreases monotonically with increasing temperature after annealing.The dielectric constant is increased with decreasing content of F in the films and the optical band gap is decreased with decreasing the content of H in the film.     

浅谈BaO-Ln2O3-TiO2体系微波介质陶瓷的热稳定性

本文介绍了目前提高BaO-Ln2O3-TiO2体系微波介质陶瓷热稳定性的几种方法,指出了有待解决的主要问题;而加强对陶瓷结构的理论剖析、寻找合适的添加剂、改进制备工艺等是今后研究工作的重点。     

钛酸锶钡陶瓷材料的掺杂改性

钛酸锶钡(BST)是一种重要的具有钙钛矿结构的铁电材料。顺电态下,其介电损耗较小,结构稳定。因此对顺电态下的BST进行掺杂改性是近年来铁电材料的研究热点之一。本文简要介绍了目前国内外科研工作者利用稀土、碱土氧化物进行掺杂时对BST的微观结构、介电损耗、介电常数以及可调率方面的影响。     

不同SO3掺量下C3S矿物的形成

通过化学分析,应用等温煅烧的方法对不同SO3掺量为(0%,1%,2%,3%,3.5%,5%)的C3S矿物形成过程从动力学角度进行了系统探讨.通过拟合得到了C3S矿物形成的动力学模型,并根据该动力学模型对不同SO3掺量下C3S矿物形成的速率常数进行了计算.结果表明:在1450℃,不同SO3掺量下,C3S矿物形成由三维球形对称扩散动力学模型f(a)=(1-3√(x+y)2控制;随着SO3加入量的增加,C3S矿物形成的速率常数呈非线性变化;从游离CaO的含量和反应速率常数的角度来说,SO3的加入有利于C3S的形成.并且SO3加入量的增加有利于C3S的多相体M1的稳定.     

掺钇铌酸锌铋陶瓷的介电性能

通过X射线衍射、扫描电镜、精密阻抗分析仪等对A位Y3 取代的Bi(1.5-x)YxZnNb1.5O7介质陶瓷样品的结构和介电性能进行了研究.结果表明:当Y3 取代量较少时(x≤0.2),样品保持立方焦绿石结构;当Y3 取代较多时(x≥0.4),样品出现第二相.随着取代量的增加,样品的致密化温度升高,表观密度减小,晶粒尺寸减小,介电常数减小,介电损耗增加.Y3 取代后(x≤0.8),样品的温度系数得到优化,且具有良好的高频稳定性.低温的介电弛豫现象随着Y3 取代的增加发生有规律的变化,表现为介电常数下降,介电常数峰宽化和平坦.     

葫芦脲[6]与胭脂红配合物的稳定常数

采用分光光度法研究了葫芦脲与胭脂红所形成配合物的可见吸收光谱变化,推导出吸光度与浓度变化的相关方程,确定出葫芦脲与胭脂红形成配合物的稳定常数为K=1056.1.     

Ba（Sn0．1Ti0．9）O3粉体的熔盐法制备与性质

采用熔盐法研究了Ba（Sn0．1Ti0．9）O3铁电体粉体的制备工艺和粉体性质。探讨了在熔盐催化下，合成温度对Ba（Sn0．1Ti0．9）O3反应完全程度及粉体形态的影响。结果表明，当反应温度达到900℃时，在熔盐环境下即可合成单相固体Ba（Sn0．1Ti0．9）O3，随着反应温度提高，粉体尺寸变化不大，但当温度超过950℃时出现晶粒异常长大趋势。烧结陶瓷的形貌和介电性质显示陶瓷粉体烧结活性好且介电性质优良。