含氟无皂乳液P(CTFE-IBVE-SUA)的合成及性能研究

通过无皂乳液聚合法制备得到聚(三氟氯乙烯-乙烯基异丁基醚-十一烯酸钠)[P(CTFE-IBVE-SUA)]含氟乳液。考察了单体配比对聚合反应的影响,研究了SUA用量对乳液及聚合物性能的影响,并对聚合物的结构及乳胶粒的形貌进行了测定。结果表明:含氟无皂乳液P(CTFE-IBVE-SUA)的稳定性好、粒径分布均匀;改变单体配比中IBVE和CTFE的比例可以得到不同结构的含氟聚合物乳液;SUA用量对乳液的稳定性、乳胶粒的粒径大小及粒径分布、聚合物膜与水的接触角都有很大的影响;制得的乳液具有明显的核壳结构。     

甲基丙烯酸2,2,2-三氟乙酯的ATRP乳液聚合

采用原子转移自由基聚合(ATRP)乳液聚合,合成了结构明确且相对分子质量分布窄的聚甲基丙烯酸2,2,2-三氟乙酯。催化剂、引发剂、乳化剂等都影响ATRP乳液聚合,使用非离子型乳化剂油醇聚氧乙烯醚所得乳液稳定,只有少量凝胶出现,所得聚合物相对分子质量实际值与理论值较为一致。随着乳化剂、催化剂、引发剂用量的增加,相对分子质量增大,聚合反应速率逐渐加快。ATRP乳液聚合可得到相对分子质量分布为1.44,乳胶粒粒径为105.0 nm,粒径分布为0.211,凝胶质量分数为15%,可稳定贮存三个月的聚甲基丙烯酸2,2,2-三氟乙酯乳液。     

Numerical and experimental investigations on polymer melt flow phenomenon in a vario‐thermal mold cavity

Mold temperature is one of the key factors affecting the morphology and quality of plastic parts. This article explores the melt flow phenomena in a vario‐thermal mold cavity. A coupled numerical method, considering the conjugate heat transfer between the mold and melt, is developed for the melt flow simulation. Mold temperature variations and melt flow phenomena for short shot injection in an electrical heated mold cavity are numerically studied and verified by experiments. The results indicate that the melt flow length and cavity filling ratio increase significantly with the elongation of the preheating time before injection. Melt filling ratio increased nearly linearly with the increasing of electric heating time. The smaller the injection pressure is, the bigger the relative filling ratio increment is. Therefore, polymer melt can flow much longer or the mold cavity can be filled up with a smaller injection pressure when the cavity is preheated. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45193.     

测量工作对路面高程及平整度的控制

文中主要讨论了在道路施工测量工作中容易影响路面标高及平整度的因素及采取的相应措施,以提高工程设计人员在公路建设中的质量意识。     

面向边-端协同的并行解码器图像修复方法

针对现有神经网络图像修复方法在移动终端设备上部署存在效果差、响应时间长、高能耗的问题,提出了一种面向边-端协同的并行解码器图像修复方法及计算卸载策略。结合移动边缘计算（mobile edge computing,MEC）技术边-端协同的特性,提出一种面向边-端协同的并行解码器门控卷积图像修复网络ETG-Net(edge-terminal gated convolution network)。通过边-端共享权值的方式,提升图像修复及训练效率,并保留移动终端的独立工作能力。基于计算卸载决策,将图像修复部分计算任务有选择地卸载至边缘云,进一步降低终端节点的计算时延和能耗。实验结果表明,与近年来先进的模型相比,所提模型在保证图像修复质量的同时,解决了移动终端设备上部署图像修复模型存在的问题,降低了任务的响应时延。     

涤纶增强混凝土的性能研究

采用涤纶工业丝和相应的废弃的涤纶工业丝作混凝土的增强纤维,分别选择纤维的长度为20、30 mm和纤维的掺量为0.5、1.0、1.5 kg/m3,按国标要求制作试样并进行标准养护后,对增强混凝土的抗裂性能、抗压性能、劈裂抗拉性能和弹性模量进行测试和分析,结果表明纤维增强混凝土的上述力学性能均有所改善,试样受力破坏后不碎裂;并且随着纤维长度和掺量的增加,抗压强度和劈裂抗拉强度提高;回收涤纶与新涤纶的情况大体类似,这给废弃涤纶的回收再利用和节约资源、保护环境提供了途径。不论是涤纶还是回收涤纶,长度为30 mm、掺量为1.5 kg/m3的试样表现出最优的力学性能。     

浅谈大型沥青拌和楼的安装使用与管理

结合现今大型沥青拌和楼的施工生产实践情况,对其安装技术及生产和成本管理进行总结,为大型沥青拌和楼的合理使用和有效管理提供参考意见。     

二氧化碳联合核桃壳提取液促进单针藻Monoraphidium sp. QLZ-3的生长和油脂积累

以单针藻Monoraphidium sp. QLZ-3为对象,研究了CO₂对微藻在核桃壳提取液（walnut shell extracts,WSE）中生长及油脂积累的影响。结果显示,在12%的CO₂条件下,微藻在WSE中的生物量产率及油脂产率达到196.85mg/(L·d)和97.52mg/(L·d),分别是对照组的1.33倍和1.57倍。WSE培养下,外源CO₂上调了微藻中核酮糖1,5-二磷酸羧化酶基因（ribulose 1,5-bisphosphate carboxylase/oxygenase,rbcL）的表达量,从而促进了CO₂的固定。此外,12% 的CO₂提高了微藻对WSE中多酚的利用,同时上调了乙酰辅酶A羧化酶（acetyl coenzyme A carboxylase,ACCase）和苹果酸酶（malic enzyme,ME）活性,下调了磷酸烯醇式丙酮酸羧化酶（phosphoenolpyruvate carboxylase,PEPC）活性。研究表明,CO₂可以提高WSE中微藻的生物量产率和油脂产率,降低培养成本,为核桃壳的资源化利用及微藻的工业化生产提供了新的理论基础。     

Application of Long-Wave Near Infrared Hyperspectral Imaging for Measurement of Soluble Solid Content (SSC) in Pear

Soluble solid content (SSC) in fruit is one of the most crucial internal quality factors, which could provide valuable information for commercial decision-making. Near-infrared (NIR) technique has effective potentials for determining the SSC since NIR was sensitive to the concentrations of organic materials. In this study, a novel NIR technique, long-wave near infrared (LWNIR) hyperspectral imaging with a spectral range of 930–2548 nm, was investigated for measuring the SSC in pear, which has never been examined in the past. A new combination of Monte Carlo-uninformative variable elimination (MC-UVE) and successive projections algorithm (SPA) was proposed to select most effective variables from LWNIR hyperspectral data. The selected variables were used as the inputs of partial least square (PLS) to build calibration models for determining the SSC of ‘Ya’ pear. The results indicated that calibration model built using MC-UVE-SPA-PLS on 18 effective variables achieved the optimal performance for prediction of SSC comparing with other developed PLS models (MC-UVE-PLS and SPA-PLS) by comprehensively considering the accuracy, robustness, and complexity of models. The correlation coefficients between the predicted and actual SSC were 0.88 and 0.88 and the root mean square errors were 0.49 and 0.35 °Brix for calibration and prediction set, respectively. The overall results indicated that long-wave near infrared hyperspectral imaging incorporated to MC-UVE-SPA-PLS model could be applied as an alternative, fast, accurate, and nondestructive method for the determination of SSC in pear.     

牛奶过敏原制备方法的研究和免疫活性鉴别

目的探索牛奶主要过敏原的制备工艺。方法采用等电点沉淀、凝胶层析和分子筛等技术纯化牛奶中主要过敏原组分;采用SDS-PAGE鉴定蛋白纯度,采用双抗原夹心-ELISA鉴定免疫活性。结果成功获得牛奶中的四种主要过敏原组分:酪蛋白、β乳球蛋白、α乳白蛋白和分子量较高的P1组分,并经过免疫实验证实这四种组分均能与过敏血清产生反应,而其中β乳球蛋白和P1组分反应性较高。结论本研究探索出一种简单、实用的牛奶主要过敏原制备工艺,并证实牛奶中的β乳球蛋白和高分子量蛋白质为主要过敏原。