一次性塑料包装瓶盖(杯盖)的拉曼光谱分析

利用便携式拉曼光谱仪对收集到49个现售饮品或外卖配送饮品的一次性塑料杯盖样品和饮料瓶瓶盖样品进行检验分析,先根据样品外观进行分类,再根据拉曼位移按照成分进行分组,最后再通过计算相对峰高比进行进一步区分,都取得了较好的效果.建立了基于系统聚类的分类模型,利用主成分分析对60％的样本进行了降维和分类.最终被检样本被分为6类...     

LED芯片封装缺陷检测方法研究

引脚式LED芯片封装工艺中封装缺陷不可避免.基于p-n结的光生伏特效应和电子隧穿效应,分析了一种封装缺陷对LED支架回路光电流的影响.利用电磁感应定律对LED支架回路光电流进行非接触检测,得到LED芯片功能状态及芯片电极与引线支架问的电气连接情况,并对检测精度的影响因素进行分析.实验表明,该方法具有高检测信噪比,能够实现对封装过程LED芯片功能状态及封装缺陷的检测.计算结果与实验结果较好吻合.     

CAI在《食品包装学》上的应用

深入论述了食品包装学课程教学内容的特点。结合食品包装教学的实践,对CAI在食品包装学教学中的作用及应用中要注意的问题进行了阐述。以期使CAI课件与食品包装学教学能有机的结合,提高食品包装学的教学效果和教学质量。     

AuSn焊料预热温度对高功率半导体激光器封装质量影响的研究

为提高高功率半导体激光器封装质量,对AuSn焊料预热温度进行研究。通过分析AuSn焊料共晶原理,建立四组不同预热温度的AuSn焊料封装试验。通过对比不同预热温度下封装器件的光电参数,光谱特性及SEM检测效果,对实验结果进行分析。实验结果表明AuSn焊料的预热温度对高功率半导体激光器封装质量有重要影响,并得出AuSn焊料预热温度在235℃时高功率半导体激光器的封装质量最为理想。     

含双环戊二烯和萘环的特种环氧树脂制备与性能

以1-萘酚和双环戊二烯(DCPD)为主要原料,合成1种新型含萘环和DCPD结构的环氧树脂(NDEP),通过傅里叶红外光谱(FTIR)、核磁共振波谱(NMR)测试,结果表明产物结构与理论产物结构相同。NDEP相对分子质量为1 683,热分解温度为352℃,线形酚醛树脂固化后产品的吸水率为0.917%,大大低于邻甲酚醛环氧树脂固化物的吸水率。     

Different microstructure BaO–B2O3–SiO2 glass/ceramic composites depending on high-temperature wetting affinity

In this work, we propose a simple but effective method to fabricate BaO–B₂O₃–SiO₂ glass/ceramic composites with different microstructures that depend on the high-temperature wetting affinity. The experimental results showed that the wetting affinity between oxide ceramic and the BaO–B₂O₃–SiO₂ glass matrix could strongly affect the driving force of densification and crystallization and finally the microstructure of the glass/ceramic composites. It was found that suitable amounts of alumina powders could obviously increase the driving force for sintering of glass by increasing the capillary pressure. In this case, the contact angle between alumina and glass matrix is about 24° at high temperature and a densified and homogeneous microstructure of glass/alumina composite was obtained. On the contrary, rutile powders additive was found to result in higher phase separation and crystallization during the sintering of glass/rutile composites. In this case, the contact angle between rutile and glass matrix is about 124° at high temperature, and the sintered body has a lower dielectric loss than the sample with alumina additive. Therefore, the microstructure and dielectric property of glass/ceramic composites could be controlled by adjusting the ceramic composition and wetting affinity between ceramic additive and glass matrix in our study.     

用于金属密封联接的自动热压封接设备研制

针对手工作业难以保证铟封工艺的质量和一致性,研制了一台自动热压封接设备,用于实现某型号精密金属器件的密封。分析了金属铟封的热压工艺过程和工艺参数;介绍了自动热压封接设备的基本结构和控制系统;详细说明了设备温度、压力等工艺参数的控制方法,并对研制设备的压力、温度的控制性能进行了测试实验。使用研制的设备进行了热压铟封实验,并对连接的可靠性和密封性能进行了测试。结果表明,热压铟封后的金属器件符合产品要求。该设备能够保证精密金属器件的封接质量和一致性,提高了铟封工艺的自动化程度,提高了生产效率。     

Incorporating amylopectin in poly(lactic acid) by melt blending using poly(ethylene‐co‐vinyl alcohol) as a thermoplastic carrier. (I) morphological characterization

In this study, the possibility of using a biodegradable grade of thermoplastic poly(ethylene‐co‐vinyl alcohol) with high (71 mol %) vinyl alcohol (EVOH‐29), as a carrier to incorporate the renewable and biodegradable component amylopectin (AP) into poly(lactic acid) (PLA) through melt blending, was investigated. The effect of using a plasticizer/compatibilizer (glycerol) in the blend systems was also investigated. In a first step, the EVOH/AP blends were produced and thereafter, in a second step, these were mixed with PLA. In this first study, the blend morphology was investigated using optical microscopy, scanning electron microscopy and Raman imaging spectroscopy and the thermal properties were measured by differential scanning calorimetry. Despite the fact that EVOH and AP are both highly polar, their blends were immiscible. Still, the blends exhibited an excellent phase dispersion on a micron level, which was enhanced further by the addition of glycerol. A good phase dispersion was finally observed by incorporation of the latter blends in the PLA matrix, suggesting that the proposed blending route can be successfully applied for these systems. Finally, the Differential scanning calorimetry (DSC) data showed that the melting point of EVOH dropped in the EVOH/AP blends, but the properties of the PLA phase was still relatively unaffected as a result of blending with the above components. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and properties of glass cloth‐reinforced polyimide composites with improved impact toughness for microelectronics packaging substrates

A series of glass cloth‐reinforced thermosetting polyimide composites (EG/HTPI) were prepared from E‐glass cloth (EG) and polyimide matrix resins. The polyimide resins were derived from 1,4‐bis(4‐amino‐2‐ trifluoromethyl‐phenoxy)benzene, p‐phenylenediamine, diethyl ester of 3,3′,4,4′‐benzophenonetetracarboxylic acid, and monoethyl ester of cis‐5‐norbornene‐endo‐2,3‐dicarboxylic acid. Based on the rheological properties of the B‐staged polyimide resins, the optimized molding cycles were designed to fabricate the EG/HTPI laminates and the copper‐clad laminates (Cu/EG/HTPI). Experimental results indicated that the EG/HTPI composites exhibited high thermal stability and outstanding mechanical properties. They had flexural strength of >534 MPa, flexural modulus of >20.0 GPa, and impact toughness of >46.9 kJ/m². The EG/HTPI composites also showed good electrical and dielectric properties. Moreover, the EG/HTPI laminates exhibited peel strength of ～ 1.2 N/mm and great isothermal stability at 288°C for 60 min, showing good potential for application in high density packaging substrates. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Novel clay‐based nanobiocomposites of biopolyesters with synergistic barrier to UV light,gas, and vapour

This article presents novel solvent cast biocomposites of poly(lactic acid) (PLA), polyhydroxybutyrate‐co‐valerate (PHBV), and polycaprolactone (PCL) with enhanced barrier properties to UV light, oxygen, water, and limonene by means of incorporating an organomodified mica‐based clay grade. The TEM results suggested a good clay dispersion but with no exfoliation in the three biopolyesters. In agreement with the crystallinity data, which was found to generally increase with increasing filler content, oxygen but specially water and d ‐limonene permeability coefficients were seen to decrease to a significant extent in the biocomposites and an optimum property balance was found for 5 wt % of clay loading in the three biopolymers. With increasing clay content, the light transmission of these biodegradable biocomposites decreased by up to 90% in the UV wavelength region due to the specific UV blocking nature of the clay used. As a result, these new biocomposites can have significant potential to develop packaging films, coatings and membranes with enhanced gas and vapor barrier properties and UV blocking performance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010