To improve the dynamic performance of sandwich panels, a bamboo bio-inspired core structural sandwich panel was designed, and two other general structures of sandwich panels, namely, cubic and honeycomb, were designed for comparison. These structural sandwich panels were manufactured using the fused deposition modeling technique. The dynamic responses of sandwich panels with different core structures under 5, 10, and 15 J of impact energy were evaluated and compared through low-velocity impact (LVI) tests. Finally, the non-destructive characterization method was employed to analyze the failure mechanism. Results indicate that the bamboo structural sandwich panels achieved maximum load capacity and absorbed the most energy among the three structural sandwich panels. The bamboo structure exhibited the best performance as the core structure of sandwich panels in resisting LVI. That is, the higher the impact energy and velocity are, the stronger and more brittle the sandwich are.

Mineral oil saturated hydrocarbons (MOSHs) are commonly found in food packaging printing inks. They can migrate into packaged food, posing risks to human health.In this study, a bio-based coating using sugarcane fibre (SF), anionic starch (AS), nanofibrated cellulose (NFC), and chitosan (CTS) is developed and applied to the internal surface of a food packaging white cardboard. The coating is investigated for its efficiency in reducing MOSH migration into dry food simulants (Porapak). The MOSH adsorption capacity of coated white cardboard is 4.6 and 14 times greater than those of uncoated and polythene (PE)-coated versions, respectively. Hence, the surface of SF-AS-NFC-CTS coating functions as a sponge and protective screen, adsorbing and hindering significant amounts of MOSH and subsequently slowing and reducing the migration of MOSH to food.Meanwhile, the basic properties, such as mechanical properties, air permeability (barrier property to MOSH), oil resistance, thermal stability, and antibacterial efficacy, of the coated cardboard for food packaging are all improved. Therefore, this study can offer a promising solution to food contamination concerns for food packaging.

Over the past decades, various types of hydrogels have been developed and used in the food sector to solve real-life problems. Three-dimensional (3D) printing technology can customize special surface morphologies, overall shapes, and other functionalized structures for hydrogels. Green and economical 3D printed cellulose hydrogels are rapidly attracting the research interest of researchers, especially in the field of food, where 3D printed cellulose hydrogels have a great potential for uses such as food printing or food preservation packaging. This paper summarizes and analyzes for the first time the crosslinking principle and enhancement mechanism assumed by cellulose in the research related to 3D printing cellulose hydrogels. The multi-hydroxyl character of cellulose makes it have great modification potential, which can participate in all kinds of physical or chemical crosslinking reactions, and its own elongated shape also helps it to be intertwined with other components. At the same time, cellulose promotes diverse effects on 3D printing hydrogel matrix, which not only improves the mechanical properties, shear-thinning properties, and swelling properties of the matrix, but also confers anisotropic characteristics to the hydrogel matrix, or can be used as a stabilizing support for expensive and rare materials by taking advantage of cellulose's inexpensive nature. This review provides a reference for future research on the 3D printing and molding of cellulose hydrogels and their use in the food field, and it is hoped that more and more researchers will pay attention to the abundant cellulose resources.

Background: Nitrite has been involved in many food processing techniques and its excessive consumption is closely related to the development of different diseases. Therefore, highly sensitive detection of nitrite is significant to ensure food safety. Result: This study presents a simple and novel strategy for the highly sensitive detection of nitrite in food using paper-based analytical devices (PADs). In this proposed strategy, the nitrite present in the sample undergoes efficient diazotization when initially mixed with sulfanilamide solution before reacting with N-(1-naphthyl) ethylenediamine dihydrochloride (NED) coated on the detection region of the PAD, leading to the maximum production of colored azo compounds. Specifically, within the concentration range of 0.1 -20 mg/L, the LOD and LOQ for the nitrite assay using the premixing strategy are determined as 0.053 mg/L and 0.18 mg/L, respectively which significantly surpass the corresponding values of 0.18 mg/L (LOD) and 0.61 mg/L (LOQ) achieved with the regular Griess reagent analysis. Significance: The study highlights the critical importance of the premixing strategy in nitrite detection. Under optimized conditions, the strategy demonstrates an excellent limit of detection (LOD) and limit of quantification (LOQ) for nitrite detection in eight different meat samples. In addition to its high precision, the strategy is applicable in the field of nitrite analysis. This strategy could facilitate rapid and cost-effective nitrite analysis in real food samples, ensuring food safety and quality analysis.

新鲜果蔬最主要的特点就是新鲜,能够为人体提供各种营养元素.但如果新鲜果蔬长时间处于高温环境下,会出现失水乃至出现被霉菌侵蚀的情况,从而导致腐烂的现象.我国每年有近30％的果蔬因没有及时保鲜或冷链运输而腐烂.

目的 采用改性环境友好型涂料对牛皮纸表面进行涂布,以改善其水性油墨柔性版印刷效果.方法 采用表面涂布法,使用15μm的线棒,以42 mm/s的速度,在牛皮纸表面均匀涂布纳米纤维素(CNC)复合壳聚糖(CTS)阴离子淀粉涂料,然后对涂布前和涂布后的牛皮纸水性油墨的印刷适性进行对比分析.结果 与未涂布牛皮纸相比,涂布后牛皮纸的平滑度提高了约28.6％,光泽度提高了近1倍,撕裂度提高了约19.3％,耐折度提高了约15.2％,吸水性由196.2 g/m2降至174.2 g/m2,印刷图文的密度得到显著提高,耐摩擦性较好,同时还提高了牛皮纸的抗菌性.结论 CNC?CTS阴离子淀粉涂料可以在不增加环境压力的情况下,有效提高牛皮纸的撕裂度、耐折度等力学性能,平滑度、光泽度等光学性能,以及抗水性和抗菌性,从而提高了印刷图文的印刷密度、耐摩擦性,以及印刷品的抗霉菌能力.

Carboxylated cellulose nanocrystal whisker (C-CNC) and chitosan (CTS) were used to blend and reinforce anionic starch (AS) to prepare a paper-coating agent, AS-CNC-CTS, which was coated on one side of the surface of offset paper and kraft paper. Scanning electron microscopy (SEM) showed that the AS-CNC-CTS coating agent can form a layer of dense film on the paper surface and fill the surface pores. And also, owing to the irregular pore structure of the paper, the coating agent penetrated the pores to different degrees. The structure and mechanical properties of the coated paper were analyzed using a Fourier infrared spectrometer, computer-controlled paper-tearing tester and paper tensile strength test machine. Peptide bonding interaction between C-CNC and CTS, hydrogen bonding between C-CNC and CTS, C-CNC and AS, C-CNC and paper fibers, as well as electrostatic attraction between acidified CTS and AS were found. Moreover, the coating agent also had good antibacterial properties, and no mold spots formed throughout the observation period (60d). The gas-barrier properties and oil resistance of the coated paper were further studied using a paper and paperboard air permeability tester and a paper oil-permeability tester. Results showed that the coating agent can significantly enhance the gas-barrier properties and oil resistance of paper. Furthermore, with increased C-CNC content in the coating agent, its barrier properties gradually increased. This finding indicated that the coating preparation had no effect on the crystal region of C-CNC.

为提升图文信息处理课程的教学效果,在教学中引入“竞赛+项目”式翻转课堂教学模式,将平版制版员竞赛工种所涵盖的核心专业技能与课程教学内容进行有效的衔接与融合,设计了5个教学项目,文章以其中1个子项目为例阐述了翻转课堂的实施过程.以2018级印刷媒体技术专业3个班为研究对象,一班和二班采用翻转课堂教学模式,三班采用传统讲授法授课.结果 表明,采用“竞赛+项目”式翻转课堂教学模式可以提升学生的学习兴趣,增加师生互动交流,明显提升学生成绩.该教学模式得到了学生的充分认可.

为了提高熔融沉积成型(FDM)制品的质量,采用田口试验法研究填充密度、沉积方向和填充图案三个因素对聚乳酸(PLA)制品拉伸性能的影响.结果表明,加工工艺参数对拉伸弹性模量和拉伸强度的影响程度均为沉积方向>填充密度>填充图案,其中拉伸弹性模量最优化的参数组合为填充密度100％、沉积方向45°、填充图案网格形状,拉伸强度最优化的参数组合为填充密度70％、沉积方向45°、填充图案网格形状.通过扫描电子显微镜对拉伸试验失效断面进行观察分析,探究了FDM打印工艺参数之沉积方向、填充密度对PLA试样拉伸失效的影响及其失效机理,其表征分析与试验结果高度吻合,表明该研究结果具有较好的借鉴意义.

基于频域法利用矢量网络分析仪对3种不同基材但层叠结构完全一致的高速PCB上85Ω 差分微带线在覆盖阻焊油墨前后插损的变化情况进行了研究.结果表明,以4 GHz条件下S7083基材为例,覆盖不同阻焊油墨后,微带线插损增量绝对值在0.03 dB/in至0.09 dB/in之间变化;印刷1次及2次LP-4G-G11阻焊油墨后,微带线插损绝对值增量由0.05 dB/in增加至0.07 dB/in;由较低Dk与Df材料所制备的PCB,在覆盖相同的阻焊油墨之后,微带线插入损耗值增量绝对值较大.

针对封盒装置滑动轴承在生产过程中故障率高、可靠性低的问题,课题组提出了一种基于思维进化算法(MEA)的BP神经网络滑动轴承故障诊断方法.该方法通过多次的趋同和异化操作,不断优化BP神经网络的初始权值和阀值,建立了基于MEA-BP神经网络的滑动轴承故障诊断模型.利用样本集训练、测试和验证MEA-BP故障诊断模型,结果表明MEA-BP故障诊断法较未经优化的BP神经网络故障诊断法优势明显,能够较好地用于封盒装置滑动轴承的故障诊断,延长滑动轴承无故障使用时间.课题组的研究可提高包装企业生产效率.

为适应印刷媒体技术专业的发展趋势,深化教学改革,不断提高教育教学水平,使"印刷材料与适性"课程更好地满足高职印刷媒体技术专业培养目标的需求,课程组将基于MOOCs的翻转课堂引入实际教学中,既充分调动了学生学习的积极性与主动性,使学生掌握了印刷材料相关理论知识,及材料发展前沿情况,又有效利用课上时间与同学、老师面对面交流,就实践操作过程中遇到的问题进行分析、解决,提高了学生分析、解决问题以及实践应用的能力.鉴于此,文章将翻转课堂实施的相关情况进行了总结,探讨该方法在"印刷材料与适性"课程教学中的适用性,并总结相关经验,以期为该课程和本专业相关课程教学模式改革,提供一定的参考.

为提高基于扫描电子显微镜(SEM)图像处理的印刷纸张孔隙率计算方法的准确率和适应能力,本文提出了一种基于阈值回归的纸张孔隙率计算方法,并建立SEM图像分析程序.本方法首先针对小部分样品同时进行物理实验和SEM图像处理,将两部分数据组合到一起并用于训练阈值回归模型获取模型参数;然后针对其他样品,通过回归模型获取图像分割的最佳阈值,并应用于基于SEM图像的非涂布纸张孔隙率计算过程.验证实验表明,该阈值回归模型应用于非涂布纸张孔隙率计算时,能有效提高阈值选择的客观性和计算结果的稳定性,同时提高了计算机对非涂布纸张SEM图像处理方法的适应能力.

目的 研究温湿度对蜂窝纸板力学性能的影响规律,提高蜂窝纸制品包装在高温高湿环境下的承载性能和使用寿命.方法 制作不同温湿度参数下处理的蜂窝纸板试样,进行静态压缩试验,得到其应力-应变曲线;建立一定温湿度环境下的蜂窝纸板有限元模型,进行有限元仿真分析,得到其位移云图和应力-应变曲线,并与试验结果 进行对比分析.结果 蜂窝纸板静态压缩试验结果 和有限元仿真结果 相似,包括弹性、屈服和平台等阶段,试验和有限元分析所得的应力-应变曲线吻合.蜂窝纸板的等效弹性模量和屈服应力与温湿度有关,且随着相对湿度的增大而减少,随着温度的升高而增加.结论 通过试验研究和有限元分析,发现湿度对蜂窝纸板力学性能影响显著,研究结果 对蜂窝纸制品包装的承载应用有重要参考价值.

The factors affecting the migration of organic contaminants from paper packaging materials into packaged dry powdered food were studied. Based on the molecular structure, volatile, molecular weight, and harm posed to the human body, five organic substances were selected as simulated pollutants. According to EU technical standard BS EN13130-1:2004 (E) migration trough types E manufactured migration cell and completion of migration of simulated contaminants from paper to solid powdered foods at different temperature and times were studied. GC-MS technology was used to detect the content of simulated pollutants in paper and food. Partial least-squares (PLS) method was used to analyze the effects of various factors affecting migration performance. Results showed that the migration of simulated pollutants from paper packaging materials into solid powdered foods was affected by temperature, contact time, molecular weight of organic pollutants, and volatile. Among them, volatile and molecular weight contributed the greatest effects, whereas temperature contributed the least effect. Changes in temperature and contact time were positively correlated with migration performance, whereas volatile, molecular weight, molecular polarity of organic pollutants were negatively correlated. In other words, for the individual factors, higher temperature and longer contact time meant higher migration percentage of organic pollutants from paper-based packaging to packaged dry powdered foods, whereas greater volatile and higher molecular weight of organic pollutants led to poorer migration into food.

Herein, we report a rapid screening method for evaluating the hydrocarbon contamination in paper samples by headspace gas chromatography (HS-GC). This method was based on conducting the near-complete migratable release of hydrocarbons from a paper matrix to the headspace in 35 min at 98 °C. By programming the GC column temperature, other co-existing volatile organic compounds in the sample can be effectively separated from the migratable hydrocarbons. To simplify the method calibration, the concept of total migratable hydrocarbons was introduced and n-pentadecane was used as the standard hydrocarbon compound in the calibration. The results indicate that the present method offers good precision (the relative standard deviation < 9.8%) and accuracy (recovery between 94.3 and 101%). The present method can be a valuable tool for the quality assessment of total migratable hydrocarbons of paper products, aiming at providing a good guidance for safely using the recycled paper-based materials in various applications.

A survey of 9 paper samples (including printed and non-printed, coated and non-coated with paraffin ) intended for food contact has been undertaken. Extracted with hexane by Accelerated Solvent Extraction (ASE) with sequential analysis by Gas Chromatography Mass Spectrum （ GC-MS ） to identify mineral oil saturated hydrocarbons (MOSH) in these samples. It shows that there are amount of 352-3123mg. Kg-1 n-alkanes mixture:C16-C44 MOSH in the samples. In this paper, MOSH in the paper samples were quantified. And for comparative purpose, 3 corresponding blank samples which were not printed were analyzed as described above. Results show that contents of MOSH in the printed and paraffin coated ones are higher than the blank ones. Consequently, printing inks and paraffin are the main sources of the MOSH and controlling the quality of printing inks and paraffin is the best way to ensure the security of paper food packaging materials and the consumers’ health.

混合式课堂教学模式在高职教育中得到广泛应用.本文以《图文信息处理》课程为例,创新实践了高职院校线上线下混合式课堂教学模式的构建与实践过程,调动了学生的学习兴趣,取得了较好的效果.

目的:为了得到符合复制标准的印刷品,对 CTP 印版做适当的印刷补偿.方法:采用 CTP 制版机输出灰梯尺印版,测量梯尺各阶调网点的网点面积率,将测得的数值输入到印通曲线管理模块,软件进行自动计算生成印版线性化曲线.调用生成的印版线性化曲线输出印版,将印版在纸张上面印刷后测得梯尺各级网点值,将网点值输入到印通曲线管理模块,制作出 CTP 印刷补偿曲线.结果: CTP 版线性化校正之后,整个阶调网点还原都控制± 0 . 8 %之内,达到了网点还原最佳状态,制作出来的 CTP 版符合要求.调用生成的 CTP 印刷补偿曲线进行制版和印刷,可以使样张上的网点扩大值整体缩小,除黄版偏差较大外, 50 %处的网点扩大值均降至 15 %以内.结论:对 CTP 制版机进行线性化校正和印刷补偿,可使输出最终印品和 ISO 要求达到一致.

The work aims to study the role of each performance of paper and printing ink (among the factors that affect the quality of offset image) in the saturation, gloss and abrasion resistance, etc. 2 kinds of inks were used for the offset printing of 3 types of kraft paper. Then, partial least square (PLS) was used to analyze the effects of smoothness, gloss, surface pore and ink viscosity of the paper and the particle size, etc. on the color saturation and gloss of the image and the friction resistance of ink layer. The results showed that the paper gloss and surface average aperture had significant impact on the offset image quality, had small impact on the smoothness and relative aperture depth of the paper, and had the least impact on the performances of the ink. The correlation between saturation, gloss and friction resistance tion change) of the offset image and smoothness, pore relative depth and gloss of the paper was large; while the correlation with other influence factors was relatively small. In conclusion, in the process of offset printing, the improvement of gloss and smoothness of the paper and the proper adjustment to surface average aperture and pore relative depth of the paper can improve the image quality largely.