仿瓷密胺塑料餐具中甲醛单体迁移量的研究

将合格的仿瓷餐具(又称密胺餐具)汤勺分别浸泡在不同温度(50、60、70、80、90和100℃)的纯净水和4%乙酸溶液中,通过乙酰丙酮分光光度法测定甲醛单体迁移量发现:以纯净水为浸泡液,浸泡60和120 min后,温度低于80℃的样品中均未检验出甲醛,但温度高于80℃,甲醛单体迁移量明显增加,浸泡时间越长增加越多。以4%乙酸溶液为浸泡液,浸泡60 min后,温度低于80℃的样品中均检测出了少量的甲醛,而温度高于80℃,甲醛单体迁移量更是急剧增加,且显著高于浸泡在纯净水中。结果表明,仿瓷餐具应避免盛放酸性食物和热的食物,避免放入沸水中消毒,避免作为容器长期储存食品。     

竹纤维密胺餐具中单体物质界面迁移的机理研究

目的 分析竹纤维密胺复合制品中有害单体物质在材料中扩散系数（Diffusion Coefficient,DC）的影响因素，探索其特定迁移量变化的规律和界面迁移机理。方法 本文以相同原料、不同工艺制成的竹纤维密胺餐具为试验样本，采用液相色谱仪、紫外分光光度计、扫描电子显微镜/能谱仪等方法研究了竹纤维密胺复合制品中三聚氰胺和甲醛残留单体的含量、特定迁移量、材料结构、扩散系数之间的关系和影响。结果 不同工艺制成的样本存在界面结构和残留单体浓度差异是影响单体物质扩散系数的主要内在因素。扩散系数是单体物质界面浓度因素和材料结构因素共同作用后形成的变量。随着浸泡时间的增加，模拟液对材料表面结构造成破坏，会促使扩散系数变大。同时，材料内单体浓度也在发生变化，单体浓度和界面结构共同影响下致使扩散系数增加或减少。结论 竹纤维密胺复合制品在单体物质特定迁移量的试验过程中，由于界面结构的变化，影响了扩散系数，验证了特定迁移量数值上的变化规律，为评价竹纤维密胺制品的安全性提供了参考。     

密胺餐具中三聚氰胺单体的迁移研究

采用高效液相色谱法(HPLC)测定了密胺餐具中三聚氰胺单体的迁移量。研究了2种不同材质(脲醛表面覆密胺的制品、密胺树脂模塑制品)中三聚氰胺单体的迁移行为,以及浸泡温度和浸泡时间对密胺餐具中三聚氰胺迁移量的影响。实验结果表明:随着浸泡温度的升高,三聚氰胺单体的迁出量呈上升的趋势;特定温度下,三聚氰胺的迁出量随着浸泡时间的延长而增大。市面购得密胺餐具96份,其中密胺树脂模塑制品51份,脲醛表面覆密胺制品45份,脲醛表面覆密胺制品中三聚氰胺单体迁移量的合格率低于密胺树脂模塑制品。     

密胺餐具中甲醛和三聚氰胺单体的迁移率研究进展

综述了密胺餐具中2种具危害性的残留单体——甲醛和三聚氰胺的迁移率检测方法及其迁移机理的研究现状。分析了各单体迁移率检测方法在实验室常规检验中的可行性和适用程度;重点总结了影响密胺餐具中各单体残留量的多种因素的最新研究进展;最后展望了密胺餐具的单体迁移行为的研究方向。     

教你识别优劣仿瓷餐具

仿瓷餐具也叫密胺餐具,是在餐馆、家庭广泛使用的新型餐具。据专家介绍,根据国家相关规定,严禁用尿素甲醛树脂替代密胺树脂生产制造仿瓷餐具,因为尿素甲醛树脂在相对较高的温度下,遇到水就会溶解出甲醛,而甲醛是公认的致癌物质。     

塑料密胺餐具产业质量现状分析

本文从密胺餐具的基本情况、使用风险隐患、国家各级监督抽查情况、贸易风险、新标准实施风险对密胺餐具的产业现状进行分析,并对企业和监管部门提出建议。     

密胺餐具总迁移量的研究

以密胺餐具为研究对象,按照GB31604.8-2016,分别以4%乙酸(70℃,2h)、20%乙醇(70℃,2h)、95%乙醇(60℃,2h)、4%乙酸(100℃,1h)、20%乙醇(回流温度,1h)、95%乙醇(60℃,3h)、4%乙酸(121℃,1h)、20%乙醇(回流温度,2h)、95%乙醇(60℃,4h)作为迁移实验条件对其总迁移量进行研究。结果表明:同一浸泡温度时间条件下总迁移量4%乙酸95%乙醇20%乙醇,同一模拟液条件下总迁移量随着浸泡温度的升高而增大。即密胺餐具与酸性食品在高温下接触更容易迁移出非挥发性物质。     

仿瓷餐具安全性探究——不合格仿瓷餐具的潜在安全隐患不可漠视

目前市场上的餐具一般分为三类材质：陶瓷、密胺和不锈钢。陶瓷材质餐具的安全性、色彩、光泽及艺术气质都让人爱不释手,但易碎、价格较高,从而使人们更加青睐于与陶瓷相似、价格便宜、又抗摔耐用的密胺餐具（仿瓷餐具）。     

分光光度法测定食品容器用三聚氰胺-甲醛成型品中甲醛单体迁移量

本文研究采用分光光度法测定食品容器用三聚氰胺-甲醛成型品的甲醛单体迁移量。样品采用常规直接浸泡法、微波条件浸泡法两种不同前处理方式后直接通过分光光度计分析甲醛单体迁移量。结果表明常规直接浸泡法(酸、水条件)与微波条件浸泡法(酸、水、醇条件)均有甲醛迁移出。两种浸泡方法比较:微波条件下甲醛单体迁移量较大。     

色迁移与色渗透问题剖析

塑料薄膜印刷结构后，在收卷、熟化、成品堆积及用户后处理加工和使用阶段，有时会产生色迁移与色渗透问题。色迁移指印刷面的图案颜色影印到紧密接触的薄膜或其他物品上，如收卷后在未印刷的一面也有了印刷面淡淡的图案。色渗透指印刷面的图案颜色透过薄膜而     

凝固科学技术与材料

从凝固科学与实践发展的角度介绍了当前凝固材料体系的基本框架和凝固科学主要发展阶段的基本理论。作为材料科学与工程的基本组成，凝固科学技术正在现代科学理论的基础上针对传统材料的改性提高和新材料的发展需求，以控形、控构、控性为目标开展优质铸件的定向、晶体生长、快凝、深过冷及各种新型和超常领域凝固过程的研究，并介绍了其中某些方面和展望了可能的发展趋势。     

Development and challenges of planning and scheduling for petroleum and petrochemical production

Production planning and scheduling are becoming the core of production management, which support the decision of a petrochemical company. The optimization of production planning and scheduling is attempted by every refinery because it gains additional profit and stabilizes the daily production. The optimization problem considered in industry and academic research is of different levels of realism and complexity, thus increasing the gap. Operation research with mathematical programming is a conventional approach used to address the planning and scheduling problem. Additionally, modeling the processes, objectives, and constraints and developing the optimization algorithms are significant for industry and research. This paper introduces the perspective of production planning and scheduling from the development viewpoint.     

江澳两地高校文创设计的协同研究与商业实践

目的 探索江门世遗文化的传承、发展和转化的新思路,践行国家在《粤港澳大湾区发展规划》纲要中要求江门承担与港澳地区文化创意合作与开发任务的分工。方法 与澳门高校紧密合作,开展专业培训课程,以开平碉楼为例,从人文视角开展设计研究,梳理开平碉楼的文化脉络,把世遗文化的元素和其背后的文化融入文创产品中,提升文创产品的附加值,推动当地文创产业结构的变革。结果 两地高校构建了稳定的科研团队,开设长期有效的设计培训课程,与景区建立了研究协作关系,帮助景区构建了一套产销研的商业模式。结论 以跨区域高校合作为平台,以文创产品为抓手,依托江澳两地的资源优势,可以构建江门世遗文化全新的品牌形象,最终推动开平世遗文化的活化。     

The Candela and Photometric and Radiometric Measurements

The national measurement system for photometric and radiometric quantities is presently based upon techniques that make these quantities traceable to a high-accuracy cryogenic radiometer. The redefinition of the candela in 1979 provided the opportunity for national measurement laboratories to base their photometric measurements on optical detector technology rather than on the emission from high-temperature blackbody optical sources. The ensuing technical developments of the past 20 years, including the significant improvements in cryogenic radiometer performance, have provided the opportunity to place the fundamental maintenance of photometric quantities upon absolute detector based technology as was allowed by the 1979 redefinition. Additionally, the development of improved photodetectors has had a significant impact on the methodology in most of the radiometric measurement areas. This paper will review the status of the NIST implementation of the technical changes mandated by the 1979 redefinition of the candela and its effect upon the maintenance and dissemination of optical radiation measurements.     

Creation and motion of dislocations and fracture in metal and silicon crystals

By making a step on one surface ( ) of a rectangular small paralellepiped copper crystal, dislocations could be created by the molecular dynamic method. The dislocation created was not a complete edge dislocation but a pair of Heidenreich-Shockley partial dislocations. Each time a dislocation was created, the stress on the surface was released. Small copper crystals having a notch were pulled (until fracture), compressed and buckled by use of the molecular dynamic method. An embedded atom potential was used to represent the interaction between atoms. Dislocations were created near the tip of the notch. A very sharp yield stress was observed. The results of high speed deformations of pure silicon small crystals using the molecular dynamics are presented. The results suggest that plastic deformation may be possible for the silicon with a high speed deformation even at room temperature. Another small size single crystal, the same size and the same surfaces, was compressed using molecular dynamic method. The surfaces are {110}, {112} and {111}. The compressed direction was [111]. It was found that silicon crystals are possible to be compressed with a high speed deformation. This may suggest that silicon may be plastically deformed with high speed deformation.     

PSD和PWELCH函数的分析改进及应用

针对MATLAB中两个内建功率谱密度计算函数psd()和pwelch()计算结果迥异的现象,在功率谱密度估计理论的基础上,根据经典的周期图理论和Welch平均周期图方法,通过详细分析源程序,解析计算方法,发现psd()计算的并不是工程单边功率谱密度,而是采样信号双边谱,故与pwelch()结果迥异,另外pwelch()不能对分段信号数据进行预处理。就上述不足提出了相应的改进措施,比较验证表明改进措施行之有效。     

Density and viscosity of tetralin and trans-decalin

New measurements are reported for the density and viscosity of tetralin and trans-decalin. The density was determined from room temperature to 60°C for tetralin and to 95°C for trans-decalin. The kinematic viscosity was measured up to temperatures slightly above 100°C. Our results improve upon the values recommended by the American Petroleum Institute for these liquids.     

Miniature and MEMS-type vacuum sensors and pumps

In the paper, the observable trends of the actual research and development of selected types of miniature and MEMS-type vacuum sensors are presented. Some information about the new types of active vacuum gauges, which are offered by the leading manufacturers of the vacuum measurement instruments, is given. Next, the list of MEMS devices that need vacuum for proper operation is presented. Some aspects of vacuum-encapsulation of MEMS devices, on wafer level and package level are shown. The new conceptions of obtaining and maintenance of high and ultra-high vacuum in MEMS devices are described. They concern the conception of integration of a miniature orbitron pump on-chip with MEMS-type device or with vacuum part of the portable advanced instruments such as electron microscope, ion mass spectrometer, and free electron laser.