Efficient Luminescence from Rare‐Earth Fluoride Nanoparticles with Optically Functional Shells

Rare‐earth fluorides are a class of materials with considerable potential in optical applications. Fluoride lattices typically permit high coordination numbers for the hosted rare‐earth ions, and the high ionicity of the rare‐earth‐to‐fluorine bond leads to a wide bandgap and very low vibrational energies. These factors make rare‐earth fluorides very useful in optical applications employing vacuum ultraviolet and near‐infrared excitation. The preparation of nanometer‐sized particles has opened the door for new properties and devices if the performance of their macroscopic counterparts can be conserved in the nanometer regime. However, at small particle sizes, defect surface states and adhering water reduce the optical efficiency. These shortcomings can be reduced by applying protective shells around the luminescent cores, which can also be involved in the luminescent process.     

吸声泡沫玻璃的材料特性及其吸声性能的提高

吸声泡沫玻璃是一种无机多孔材料,它具有良好的防火和耐水性能。介绍了它的材料特性,根据测量的吸声系数分析了密度、板厚、空腔和吸湿对吸声的影响,并且采用板面钻孔和边缘留缝的方法提高其吸声性能。     

磨煤机差压料位测量装置改进与优化

耒电#3、#4机组SVEDALA双进双出磨煤机差压料位测量装置改造后,测量准确性差、故障率高,通过分析问题、持续改进后,对取样管路和测量探针以及控制方案进行改造.改造完成后,新的测量系统测量准确,无测量管路堵塞和测量失真等现象,达到提高磨煤机运行安全性和节能降耗的目的.     

微扰法测量粉末状材料介电常数的改进

一般微扰法在测量粉末状材料介电常数时,需要破坏样品将材料制成杆状或圆柱状等标准形状,同时只能在单点频率下测量,具有很大的局限性。针对上述问题,提出了一种改进的测量方法——多模谐振微扰法。该方法是在微扰法基础上的改进,适合宽频无损测量粉末状材料的介电常数。对多模谐振微扰法的测量原理、系统和方法进行了较为详细的描述,通过仿真和实验得到了相应的结果并进行了误差分析,验证了该方法的合理性和有效性。     

盒体热压成型工艺及模具设计

概述了超塑热压成型技术及其特点,针对微波铝盒体类零件的特点,讨论了影响盒体超塑热压的几个关键因素,介绍了成型零件和模具设计要点,详细分析了压力、温度和速率等工艺参数的确定及选用原则,提出对不经过预处理的供应态毛坯进行直接压制成型的超塑性等温挤压成型工艺及控制要点,提高了生产效率,实现了超塑性等温热挤压成型工艺在复杂微波...     

采用激光外差干涉仪测量光学材料光弹特性的研究

将外差干涉用于给定光学材料的光弹特性测量领域 ,提出了一种测定光弹性某些参数的新方法 ,并研制了一套气压加载装置用以测量不同应力下的折射率变化情况 ,通过实验给出了应力 折射率关系曲线 ,并对实验结果进行了分析。该方法测试方便 ,装置简单 ,可通过很小应力 (1～ 2个大气压 )获得折射率变化与应力的关系 ,折射率变化的测试精度可达 8 4× 10 - 8。     

Conversion of Fly Ash Cenosphere to Hollow Microspheres with Zeolite/Mullite Composite Shells

A seed‐induced in‐situ hydrothermal conversion technique is proposed to prepare novel hollow microspheres with zeolite/mullite composite shells from fly ash cenosphere (FAC), a solid waste with a hollow structure from coal power stations. Two groups of hollow microspheres were prepared, one with zeolite FAU/mullite composite shells and the other with zeolite LTA/mullite composite shells. The FAC in this study plays dual roles as both the template cores and the aluminosilicate nutrition contributor. The final products inherit the hollow spherical morphology of FAC and possessed bilayered shells, the outer dense shell of zeolite crystals and the inner porous shell of mullite. Such hollow zeolitic materials are expected to have many advantages in applications such as catalysis, adsorption, separation, and as releasing capsules.     

雷达隐身涂料的发展现状

隐身技术是当今世界各国重点发展的国防高技术,雷达隐身涂料是隐身技术的重要组成部分之一。本文介绍了雷达隐乘风破浪作料的发展、特点以及雷达隐身涂料的应用现状,指出雷达隐身涂料的发展趋势。     

FDTD 结合支持向量机反演各向异性材料电磁参数

本文首先介绍了太赫兹波导和3D打印技术的发展现状。3D打印作为一项新兴的技术,以数字模型文件为基础,运用粉末状金属或塑料等可粘合材料通过逐层打印的方法构造实体,打破了传统THz波导技术的局限性。本文介绍的3D打印THz波导利用聚合树脂作为打印材料,打印完成的THz波导在其传输通路上镀500nm的金,金的厚度足以支持THz传播。利用这种方法可以打印出直波导、三维弯曲面、三维Y劈和U型波导等多种结构。3D打印THz波导除传输损耗略高外,其传输模式及其特性与传统的金属波导基本一致,这种额外的传输损耗归咎于商业3D打印机的精度。     

印刷电路板供电系磁性材料涂层的应用

印刷电路板（PCB）的电磁兼容问题,随着数字电路的工作频率越来越高而变得尤为重要。本文以印刷电路板中的电源接地层供电系构造为切入点,讨论与其相关的电磁兼容问题。在高频段,印刷电路板的电源和接地层构造相当于一个平行平板谐振器,对周围的电路产生电磁干扰（EMI）。基于全腔模模型,已经发展了用于高效准确计算供电系阻抗的快速算法。利用此算法,通过计算机仿真,结果表明PCB电源接地层导体内侧增加磁性材料涂层能够提高表面阻抗,进而减小端口输入阻抗的谐振峰并改善信号完整性。     

强激光辐照下充内压圆柱壳的破坏阈值和破坏时间

建立了强激光辐照下充压圆柱壳热力学响应的物理模型和数值计算模型,求解了激光产生的非线性温度场。在此基础上,考虑塑性和屈服强度的温度相关性,求解了非线性的应力场,计算了两种不同类型圆柱壳在高功率连续CO_2激光作用下的破坏阈值,给出了破坏时间与功率密度的关系以及壳体破坏的危险区域。     

通信装备保障供应链的运用发展探析

通信系统是军队各作战要素、各种武器平台形成合力的纽带与桥梁,是军队战斗力的重要组成部分。信息化条件下,通信装备保障直接影响着指控信息的有效传递,对战斗力的发挥意义重大。本文讨论了军队通信装备保障的现状、存在的问题及供应链在通信装备保障上的应用,并分析了供应链的发展对战时装备保障能力提高的重大意义。     

对国产大型挤塑机的改进

在生产过程中发现了国产大型挤塑机存在的问题 ,对造成问题的原因进行了分析 ,并提出了改进意见。设计和改进后的该国产大型挤塑机能满足线缆制造工艺要求。     

Catalase Nanocapsules Protected by Polymer Shells for Scavenging Free Radicals of Tobacco Smoke

Free radicals in tobacco smoke trigger numerous lung diseases, which are worldwide health considerations. The ideal free‐radical, tobacco‐smoke scavenger must be highly reactive and temperature resistant. Catalases (CATs) show attractive potential to scavenge free radicals in tobacco smoke, because of their higher reaction rate compared to that of non‐catalyzed reactions. Their fragile nature, however, diminishes their catalytic activity in hot tobacco smoke. Therefore, it is essential to enhance the structural integrity and catalytic stability of these enzymes under severe environmental conditions. In order to improve the thermal stability of CATs, we have developed a facile approach to produce CAT nanocapsules (nCATs) by encapsulating a single enzyme in a polyacrylamide (PAAM) shell. The rigid polymer shells on the CATs surface prevents their free deformation. The secondary structure of the enzyme is retained and their dissociation is almost nil even under high operational temperatures. As a result, the structural stability and thermal resistance of the enzyme are significantly enhanced. The nCATs are covalently bound on cellulose acetate fibers to enable the enzyme sticking to the cigarette filters.The electron paramagnetic resonance (EPR) and Saltzman procedure reveal that the nCATs are able to efficiently scavenge 90% of the free radicals in tobacco smoke. The use of such nCATs with improved enzyme thermal stability opens up new opportunities for future application in cigarette filters.     

项目管理在质量改进活动中的应用

该文介绍了如何将产品的质量改进活动项目化。应用项目管理的理论和方法,企业可以提高质量改进活动的效率,取得良好的改善效果。     

Formation of Gold and Silver Nanoparticle Arrays and Thin Shells on Mesostructured Silica Nanofibers

Mesostructured silica nanofibers synthesized in high yields with cetyltrimethylammonium bromide as the structure‐directing agent in HBr solutions are used as templates for the assembly of Au and Ag nanoparticles and the formation of thin Au shells along the fiber axis. Presynthesized spherical Au and Ag nanoparticles are adsorbed in varying amounts onto the silica nanofibers through bifunctional linking molecules. Nonspherical Au nanoparticles with sharp tips are synthesized on the nanofibers through a seed‐mediated growth approach. The number density of nonspherical Au nanoparticles is controlled by varying the amount of seeded nanofibers relative to the amount of supplied Au precursor. This seed‐mediated growth is further used to form continuous Au shells around the silica nanofibers. Both the Au‐ and Ag‐nanoparticle/silica‐nanofiber hybrid nanostructures and silica/Au core/shell fibers exhibit extinction spectra that are distinct from the spectra of Au and Ag nanoparticles in solution, indicating the presence of new surface plasmon resonance modes in the silica/Au core/shell fibers and surface plasmon coupling between closely spaced metal nanoparticles assembled on silica nanofibers. Spherical Au‐ and Ag‐nanoparticle/silica‐nanofiber hybrid nanostructures are further used as substrates for surface‐enhanced Raman spectroscopy, and the enhancement factors of the Raman signals obtained on the Ag‐nanoparticle/silica‐nanofiber hybrid nanostructures are 2 × 10⁵ for 4‐mercaptobenzoic acid and 4‐mercaptophenol and 7 × 10⁷ for rhodamine B isothiocyanate. These hybrid nanostructures are therefore potentially useful for ultrasensitive chemical and biological sensing by using molecular vibrational signatures.     

陶瓷材料放气特性分析

利用自行研制的材料真空放气性能测试设备,对4种不同陶瓷材料样品在真空环境下的放气特性进行了测试,并对照各样品材料表明及断面扫描电镜的照片,进一步阐明了它们在高温条件下产生不同放气量的原因。     

硅质红外辐射导电材料的研制

本文根据制备高温红外辐射导电材料的基本原理，探讨了研制硅质红外辐射材料的工艺条件。     

固体物理效应与现代传感器技术

介绍了某些固体物理效应对现代传感器技术的影响。这些效应是：压电效应、压阻效应、霍尔效应、磁阻效应、约瑟夫逊效应、韦根德效应和佐托夫效应。简要描述了这些效应的原理和应用。进一步研究这些效应对于发展现代传感器技术是非常重要的。     

表面波吸收材料评估

本文给出覆盖有耗介质平面导体上表面波的表面阻抗和衰减率的计算公式，提出吸收材料导磁率的实部和虚部的乘积μ′，μｒ′和表面波衰减率分别作为吸收材料本身品质和使用效果的评估参量，给出了样品材料的衰减率的测量结果，测量值与计算值的误差小于１ｄＢ