Efficacy of thyme oil-alginate-based coating in reducing foodborne pathogens on fresh-cut apples

In this study, the inhibition of an alginate-based edible coating (EC) containing thyme oil (0.05%, 0.35% and 0.65%) was evaluated against Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus and Escherichia coli O157:H7 inoculated onto fresh-cut apples. To investigate the antibacterial mechanism of thyme oil, the constituent compounds of that were analysed by gas chromatography-mass spectrometry (GC-MS), and the cellular damage of pathogens was observed by scanning electron microscopy (SEM). Results showed that alginate-based EC containing thyme oil effectively inhibited the growth of pathogens on fresh-cut apples. GC-MS analysis revealed thymol (47.23%) as the major compounds in thyme oil. SEM showed that the cell membrane of foodborne pathogens was damaged by thyme oil, causing their inactivation. Treatment with alginate-based EC containing 0.05% thyme oil preserved the sensory characteristics of fresh-cut apples. Therefore, using alginate-based EC with thyme oil may represent a potential approach to preserve and enhance the safety of fresh-cut apples.     

Room-temperature multiferroic characteristics and unique vortex domain structures of h-Yb1−xInxFeO3 solid solutions

Hexagonal rare-earth ferrites (h-RFeO₃) have attracted much scientific attention due to their room-temperature multiferroicity. However, it is still a hard job to obtain h-RFeO₃ bulk materials because of the meta-stability of such hexagonal phase, and the evaluation of room-temperature ferroelectric and magnetoelectric characteristics in such materials is also a challengeable issue. In the present work, Yb_1−xIn_xFeO₃ ceramics with the stable hexagonal structure were obtained by introducing chemical pressure, where the unique ferroelectric domain structures of sixfold vortex combined with tenfold vortex with a typical size of ~400 nm were determined. Symmetry of the present system evolved from centrosymmetric orthorhombic Pbnm (x = 0–0.4) to non-centrosymmetric hexagonal P6₃cm (x = 0.5 and 0.6) with a ferroelectric polarization up to 3.2 μC/cm², and finally to centrosymmetric hexagonal P6₃/mmc (x = 0.7 and 0.8). The Curie point decreased monotonically from 723 K to a temperature below room temperature with increasing x, and the antiferromagnetic phase transition above room temperature was determined for all compositions. Meanwhile, a large linear magnetoelectric coefficient (α_ME) up to 0.96 mV/cm Oe was obtained at room temperature, and this indicated the great application potential for magnetoelectric devices.     

Chemical bond characteristics and infrared reflectivity spectrum of a novel microwave dielectric ceramic CaIn2O4 with near-zero τf

Orthorhombic-structured CaIn₂O₄ ceramics with a space group Pca2₁ were synthesized via a solid-state reaction method. A high relative density (95.6 %) and excellent microwave dielectric properties (ε_r ～11.28, Qf = 74,200 GHz, τ_f ～ ?4.6 ppm/°C) were obtained when the ceramics were sintered at 1375 °C for 6 h. The dielectric properties were investigated on the basis of the Phillips–Van Vechten–Levine chemical bond theory. Results indicated that the dielectric properties were mainly determined by the InO bonds in the CaIn₂O₄ ceramics. These bonds contributed more (74.65 %) to the dielectric constant than the CaO bonds (25.35 %). Furthermore, the intrinsic dielectric properties of the CaIn₂O₄ ceramics were investigated via infrared reflectivity spectroscopy. The extrapolated microwave dielectric properties were ε_r ～10.12 and Qf = 112,200 GHz. Results indicated that ion polarization is the main contributor to the dielectric constant in microwave frequency ranges.     

Property uniformity of thick nickel-based alloy plate for nuclear power steam-generator divider plate

This paper introduces a thick 690 nickel-based alloy plate produced by the former Baosteel Special Steel Co.,Ltd.used as the steam-generator divider plate in the pressurized water reactor nuclear power plant.According to the product characteristics and design requirements of the thick nickel-based alloy plate, multidimensional sampling and testing were conducted to investigate its microstructure and mechanical properties.The results show that all the property indexes of the thick hot-rolled nickel-based alloy plate meet the design requirements, and there is good uniformity in the microstructure and mechanical properties in different dimensions.These findings indicate that China has mastered the core manufacturing technology of thick nickel-based alloy plates for their use as divider plates in nuclear power steam generators.     

Personality expression and recognition in Chinese language usage

User Modeling and User-Adapted Interaction - Personality plays a pivotal role at work. Many scholars have investigated the association between personality and language usage habits in the English...     

基于芯片化配电网终端的智能环网柜研究

本次研究针对配电网终端的智能环网柜进行了芯片化设计,通过数字信号处理芯片实现多路模拟测量.综合运用DSP2047芯片装置和快速傅里叶变换算法显著提升了环网柜谐波分析能力,经实验研究发现,内置芯片模块的智能环网柜能够对谐波进行有效的控制.     

含功效成分电子烟对动物模型止咳平喘作用研究

为考察电子烟作为功效成分递送器具的效果,选取L-薄荷醇、L-茶氨酸、丁香酚、木香烃内酯、西贝碱、菖蒲酮、7,4'-二羟基黄酮7种功效化合物和1种臭灵丹提取物,通过氨水引咳小鼠咳嗽模型和卵清蛋白(OVA)引喘大鼠哮喘模型,评价上述物质在电子烟中止咳平喘疗效.结果 显示:1)止咳效果方面.上述8种物质均减少了咳嗽模型小鼠的咳嗽次数,同时不同程度延长了咳嗽模型小鼠咳嗽潜伏期;2)平喘效果方面.上述8种物质对哮喘模型大鼠肺功能各指标均有改善,其中L-薄荷醇对呼气时间(简称"Te")、50％的呼气流速(简称"EF50％")有明显改善;L-茶氨酸对Te、最大呼气流速(简称"PEF")和EF50％有明显改善;丁香酚对PEF、EF50％和呼气量(简称"EV'")有明显改善;木香烃内酯对PEF和EV有明显改善;西贝碱对Te、PEF有明显改善;菖蒲酮对Te、PEF有明显改善;7,4'-二羟基黄酮对PEF和EV有明显改善;臭灵丹提取物对PEF和EF50％有明显改善;3)Model组大鼠存在明显哮喘病理改变:肺基底膜增厚并发生玻璃样变,相比Model组,8组接受功效型电子烟烟雾暴露的哮喘模型大鼠支气管哮喘均有改善.以上说明,电子烟作为具有止咳平喘功效成分的递送器具效果明显,这为功效型电子烟的开发提供了参考.     

锯齿错列肋片尾气换热器的热电性能优化

由于尾气传热性能差,尾气余热热电转换系统中常采用具有强化换热结构的尾气换热器,其中,锯齿错列肋片式是常见型式之一.但如何平衡传热性能和流动阻力实现对换热器内部结构和整体尺寸的优化,使得热电系统获得总的净输出功率最大,是值得研究的内容.但现有成果均是基于限定尺寸结构,对换热器局部尺度及热电性能进行分析,没有针对强化换热器的整体优化结构和最大净输出功率展开研究.建立基于汽车尾气余热回收的热电转换数值模型,结合场协同理论,分析锯齿错列肋片式尾气换热器内部肋片结构对热电功率的影响.此外,综合考虑传热性能与流动阻力的平衡,以热电转换最大净输出功率为优化目标,对热电模块结构进行优化,并获得热电系统的相应最优性能.研究结果表明,固定热电模块尺寸时,净输出功随肋片高度增加明显增加,但受肋宽影响较小;对热电模块尺寸进行优化时,肋高和肋宽的变化均对热电模块的最优尺寸产生较大影响,单位面积最大净输出功随肋宽增加而明显降低,但受肋高的影响较小.