军用电子装备应用中的塑封微电路质量保证

近年来,塑封微电路凭借着其在性能、重量、尺寸、成本、采购周期以及可获得性等方面的优势,越来越多地应用在军工电子装备中,其可靠性低的问题就越来越突出。如何将这类塑封微电路更可靠地应用于不同领域的军工电子装备中,并使风险降低到可控的范围,是广大军工电子装备制造单位正在致力探索解决的问题。浅析了塑封微电路应用于军工电子装备中的优缺点,并介绍了某型塑封微电路在地面、航空这两个不同的领域应用所执行的一套质量保证方案。     

Encapsulated vacuum insulation panels: theoretical thermal optimization

A vacuum insulation panel (VIP) is a new thermal insulation material consisting of an open-celled core material which is evacuated and then sealed with a thin barrier laminate. When it is integrated into an expanded polystyrene (EPS) insulation board and entirely encapsulated by a protective material, an additional thermal bridge occurs along the component's perimeter. A theoretical parameter study examines the effects of integrating a VIP into an insulation board with a fixed thickness of 100 mm. Several parameters were varied: thermal conductivity and the thickness of the VIP core, the thickness of the envelope, the thickness of the EPS layers and the width of the EPS strips along the component's perimeter. Both two- and three-dimensional numerical studies reveal a certain VIP maximum thickness for optimal thermal performance. For the three-dimensional component, this thickness is near 30 mm or 95 mm for, respectively, a 40 µm- or a 6 µm-thick aluminium foil-based barrier laminate. For these components, the overall thermal resistance was found to be, respectively, 35% or 137% higher than a 100 mm-thick EPS insulation board. However, no maximum thermal performance was found for an encapsulated VIP containing a three-layer metallized barrier laminate.

Le panneau isolant sous vide (PIV) est un nouveau matériau d'isolation thermique comportant une âme constituée d'un matériau à pores ouverts, qui est mise sous vide et hermétiquement scellée au moyen d'une mince barrière en stratifié. Lorsque le PIV est intégré à un panneau isolant en polystyrène expansé (EPS) et entièrement encapsulé par un matériau protecteur, un pont thermique supplémentaire se produit le long du périmètre de cet élément. Une étude théorique des paramètres examine les effets de l'incorporation d'un PIV dans un panneau isolant d'une épaisseur fixe de 100 mm. Plusieurs paramètres sont modifiés: la conductivité thermique et l'épaisseur de l'âme du PIV, l'épaisseur de l'enveloppe, l'épaisseur des couches de polystyrène expansé (EPS) et la largeur des bandes de polystyrène expansé le long du périmètre de l'élément. Les études numériques aussi bien bidimensionnelles que tridimensionelles révèlent qu'une certaine épaisseur maximale des PIV permet d'obtenir un rendement thermique global. S'agissant de l'élément tridimensionnel, cette épaisseur est proche de 30 mm ou de 95 mm, respectivement, pour un stratifié basé sur une feuille d'aluminium de 40 µm ou 6 µm d'épaisseur. Concernant ces éléments, il a été constaté que la résistance thermique globale était, respectivement, de 35% ou 137% supérieure à celle d'un panneau isolant en polystyrène expansé de 100 mm. Néanmoins, il n'a été constaté aucun rendement thermique maximum pour un PIV encapsulé contenant un stratifié métallisé triple couche.

Mots clés: panneaux isolants sous vide (VIP) encapsulés, isolation, optimisation, rendement thermique, panneaux isolants sous vide     

运用于系统仿真的冰球式蓄冷罐的模型

建立了冰球式蓄冷罐的数学模型，并在TRNSIS仿真平台上编制了蓄冷罐的仿真模型；通过仿真计算数据与已有试验数据的比较，验证了该模型的合理性和准确性。     

电子墨水的组成及制备方法

电子墨水是一种新型的柔性显示材料，是由具有化学相容性的多相材料组成的。本文在介绍电子墨水显示原理的基础上，着重介绍了各组成部分，即电泳颗粒、分散介质、染料、电荷控制剂和稳定剂的作用及材料的选择，论述了电子墨水微胶囊的制备方法及存在的问题。并评述了电子墨水的研究进展。     

包覆型铝粉颜料在水性涂料中的应用

以正硅酸乙酯(TEOS)和乙烯基三乙氧基硅烷(VTES)为前驱物,通过溶胶-凝胶反应在铝颜料表面形成了一层致密的包覆层,再通过甲基丙烯酸甲酯(MMA)和丙烯酸(AA)的自由基聚合反应对铝颜料进行第二层包覆,制备了含亲水基团的包覆型铝粉颜料,以此包覆的铝颜料配制了水性铝粉涂料.研究了铝粉及交联剂的用量、涂料黏度和烘烤温度...     

声学扫描显微镜检查在塑封器件检测中的应用

随着塑封器件在武器系统中的使用越来越广泛,塑封器件在使用中也暴露出了一些问题,如塑封器件易打磨、翻新,内部易进入水汽产生爆米花效应或内部界面分层等。作者总结近几年塑封器件DPA试验中出现的各种失效,重点对塑封器件内部界面分层以及分层产生的原因、危害进行了论述。同时,论述了声学扫描显微镜检查对内部界面分层的辨别、原理及其相关试验标准等,提出了塑封器件在型号产品中的使用建议。     

Ultrastable Supramolecular Self‐Encapsulated Wide‐Bandgap Conjugated Polymers for Large‐Area and Flexible Electroluminescent Devices

Controlling chain behavior through smart molecular design provides the potential to develop ultrastable and efficient deep‐blue light‐emitting conjugated polymers (LCPs). Herein, a novel supramolecular self‐encapsulation strategy is proposed to construct a robust ultrastable conjugated polydiarylfluorene (PHDPF‐Cz) via precisely preventing excitons from interchain cross‐transfer/coupling and contamination from external trace H₂O/O₂. PHDPF‐Cz consists of a mainchain backbone where the diphenyl groups localize at the 9‐position as steric bulk moieties, and carbazole (Cz) units localize at the 4‐position as supramolecular π‐stacked synthon with the dual functionalities of self‐assembly capability and hole‐transport facility. The synergistic effect of the steric bulk groups and π‐stacked carbazoles affords PHDPF‐Cz as an ultrastable property, including spectral, morphological stability, and storage stability. In addition, PHDPF‐Cz spin‐coated gelation films also show thickness‐insensitive deep‐blue emission with respect to the reference polymers, which are suitable to construct solution‐processed large‐scale optoelectronic devices with higher reproducibility. High‐quality and uniform deep‐blue emission is observed in large‐area solution‐processed films. The electroluminescence shows high‐quality deep‐blue intrachain emission with a CIE (0.16, 0.12) and a very narrow full width at half‐maximum of 32 nm. Finally, large‐area and flexible polymer light‐emitting devices with a single‐molecular excitonic behavior are also fabricated. The supramolecular self‐encapsulation design provides an effective strategy to construct ultrastable LCPs for optoelectronic applications.     

Circulating miRNAs as Biomarkers for Mitochondrial Neuro-Gastrointestinal Encephalomyopathy

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an ultra-rare disease for which there are currently no validated outcome measures for assessing therapeutic intervention efficacy. The aim of this study was to identify a plasma and/or serum microRNA (miRNA) biomarker panel for MNGIE. Sixty-five patients and 65 age and sex matched healthy controls were recruited and assigned to one of four study phases: (i) discovery for sample size determination; (ii) candidate screening; (iii) candidate validation; and (iv) verifying the performance of the validated miRNA panel in four patients treated with erythrocyte-encapsulated thymidine phosphorylase (EE-TP), an enzyme replacement under development for MNGIE. Quantitative PCR (qPCR) was used to profile miRNAs in serum and/or plasma samples collected for the discovery, validation and performance phases, and next generation sequencing (NGS) analysis was applied to serum samples assigned to the candidate screening phase. Forty-one differentially expressed candidate miRNAs were identified in the sera of patients (p < 0.05, log₂ fold change > 1). The validation cohort revealed that of those, 27 miRNAs were upregulated in plasma and three miRNAs were upregulated in sera (p < 0.05). Through binary logistic regression analyses, five plasma miRNAs (miR-192-5p, miR-193a-5p, miR-194-5p, miR-215-5p and miR-34a-5p) and three serum miRNAs (miR-192-5p, miR-194-5p and miR-34a-5p) were shown to robustly distinguish MNGIE from healthy controls. Reduced longitudinal miRNA expression of miR-34a-5p was observed in all four patients treated with EE-TP and coincided with biochemical and clinical improvements. We recommend the inclusion of the plasma exploratory miRNA biomarker panel in future clinical trials of investigational therapies for MNGIE; it may have prognostic value for assessing clinical status.     

抗紫外聚多巴胺香料纳米胶囊缓释体系的研究

利用多巴胺(DA)在碱性溶液中的自氧化和聚合,在香料乳液液滴表面涂覆聚多巴胺(PDA)层制备香料PDA纳米胶囊,比较了PDA对不同香料的包覆性能和缓释效果。结果发现苯乙醛和香茅醛因与多巴胺(DA)发生Maillard反应而不能被包覆,苯乙醇、香茅醇、乙酸苯乙酯和乙酸香茅酯则能被包覆在纳米胶囊内部,扫描电子显微镜(SEM)和动态激光光散射(DLS)结果显示:香料纳米胶囊基本呈球形,分布较均匀,香料种类对粒径影响大,可由88 nm(乙酸香茅酯)变化到556 nm(苯乙醇)。对香茅醇的包埋率最高,可达到19. 8%,在常温下保存50 d后香料保留率可保持69. 39%以上,具有良好的缓释性能,同时由于PDA对紫外及可见光有一定的吸收,因此可以为光敏性或光毒性香料的应用提供进一步的光屏蔽作用。     

Analysis of an encapsulated phase change material‐based energy storage system for high‐temperature applications

The capability of an encapsulated phase change material (EPCM)‐based thermal energy storage (TES) system to store a large fraction of latent energy at high temperatures was examined. A 3‐dimensional simulation of a prototype heat exchanger was conducted employing sodium nitrate as the phase change material (PCM). The k‐ω SST model was used to capture the turbulent flow of the HTF, while the melting front was tracked using the enthalpy‐porosity method. The results show that the use of metal deflectors yields a nearly constant heat transfer coefficient over the capsule's surface. Despite this, the presence of the void in the capsule and natural convection within the molten PCM influenced the storage characteristics of the system affecting the shape of the isotherms and melting front. Furthermore, the EPCM capsules consecutively undergo the same heat transfer starting from the capsule closest to the inlet. The EPCM capsules store 80% of the energy lost by the HTF. The 17.7 kg of sodium nitrate stores 14.5 MJ of energy where 20% of the energy stored is via latent heat. Of the energy released by the heat transfer fluid, 80% was absorbed by the EPCM capsules with the remaining energy going into the test section walls. A total of 14.5 MJ of energy was stored by the 17.7 kg of NaNO₃, of which 20% is attributed to the latent heat. The fraction of energy stored as latent heat would be larger if a smaller operating temperature range was used. Thus, an EPCM‐based latent heat TES system is capable of storing a large fraction of the supplied energy and presents efficient means of storing thermal energy for high‐temperature applications. Additionally, the strong agreement between the numerical and experimental works demonstrates that the numerical methods employed can predict the behavior of an EPCM capsule not only within a single capsule but on the system scale as well. Therefore, the applied numerical methods can be used for further design and optimization of EPCM‐based latent heat TES systems.