Nonlinear dynamic behavior of rotating blade with breathing crack

This study aims at investigating the nonlinear dynamic behavior of rotating blade with transverse crack. A novel nonlinear rotating cracked blade model (NRCBM), which contains the spinning softening, centrifugal stiffening, Coriolis force, and crack closing effects, is developed based on continuous beam theory and strain energy release rate method. The rotating blade is considered as a cantilever beam fixed on the rigid hub with high rotating speed, and the crack is deemed to be open and close continuously in a trigonometric function way with the blade vibration. It is verified by the comparison with a finite element-based contact crack model and bilinear model that the proposed NRCBM can well capture the dynamic characteristics of the rotating blade with breathing crack. The dynamic behavior of rotating cracked blade is then investigated with NRCBM, and the nonlinear damage indicator (NDI) is introduced to characterize the nonlinearity caused by blade crack. The results show that NDI is a distinguishable indicator for the severity level estimation of the crack in rotating blade. It is found that severe crack (i.e., a closer crack position to blade root as well as larger crack depth) is expected to heavily reduce the stiffness of rotating blade and apparently result in a lower resonant frequency. Meanwhile, the super-harmonic resonances are verified to be distinguishable indicators for diagnosing the crack existence, and the third-order super-harmonic resonances can serve as an indicator for the presence of severe crack since it only distinctly appears when the crack is severe.     

鲭鱼生物胺生成菌的分离与鉴定

从鲭鱼体内分离7 株生物胺产生菌,其中3 株菌可以产生色胺,4 株菌可以产生2-苯乙胺,4 株菌可以产生腐胺,1 株菌可以产生尸胺,3 株菌可以产生组胺,1 株菌可以产生酪胺。组胺生成量较高的No.1菌株形态学、生理生化分析及菌种鉴定结果表明该菌株极有可能为侵肺巴斯德氏菌,可信度为99.9%。     

水产养殖产品精制加工与质量安全发展战略研究

本文基于对我国养殖水产品精制加工和质量安全现状、存在问题的客观分析,提出了"构建以加工引导养殖、保障消费的现代水产业发展新模式,促进养殖、加工与物流业同步发展""完善科研经费投入体制,构建以加工引导养殖、以加工保障消费的渔业科技创新体系""强化源头创新,研发关键配套技术,解决水产加工产业发展的瓶颈问题"及"加强顶层设计,增强政策、法律法规与科研项目引导,切实保障养殖水产品质量安全"等促进水产品加工业健康发展的建议,并提出了发展我国水产品加工产业的关键技术,为推动我国水产业转型升级、实现现代化提供理论支撑。     

有机硅改性聚氨酯的最新研究进展

有机硅改性聚氨酯兼具两者的优异性能，提高了聚氨酯材料的耐水、耐候等性能。对有机硅氧烷化合物改性聚氨酯的改性方法、结构特点、性能和近年来的研究成果进行了综述。     

马尾藻袋泡茶的生产技术

利用马尾藻为原料，采用掩盖法，生产没有特殊腥味的马尼藻袋泡茶饮料．该茶富含碘质，可防治甲状腺机能减退病，即碘缺乏病．     

复合添加剂对鲟鱼籽酱(Huso dauricused × sturger schrenckii)挥发性成分的影响

采用固相微萃取-气相色谱-质谱联用分析技术,分别检测未经添加剂处理的鲟鱼籽酱、添加0.5‰山梨酸钾和0.2‰抗坏血酸的鲟鱼籽酱(A1组),添加0.5‰山梨酸钾、0.2‰抗坏血酸和0.2‰乳酸链球菌素(Nisin)的鲟鱼籽酱(A2组),添加0.5‰山梨酸钾、0.2‰抗坏血酸和0.2‰L-抗坏血酸棕榈酸酯的鲟鱼籽酱(A3组),在0℃冷藏时挥发性物质的变化,经NIST 05a.L和NIST 05.l谱库数据库检索,确定其挥发性成分。结果表明:初始鲟鱼籽酱检测出46种挥发性成分,醛类物质作为主要气味贡献组分,其中壬醛、己醛、辛醛和庚醛含量较高,另外,一定含量的D-柠檬烯、长叶烯和石竹烯可能赋予新鲜鲟鱼籽酱独特的柠檬香、木香等清新气味。3组复合添加剂的使用,都有利于防止在贮藏过程中鱼籽酱挥发性物质的流失,减少了酮类和醇类物质的变化。其中,A2组中,山梨酸钾、抗坏血酸和Nisin的添加促进了贮藏3个月后鱼籽酱中醛类物质的还原反应,导致醛类物质的大量减少,酯类物质的大量增加。最后,在贮藏期间醛类物质的变化,显示A1组和A3组复合防腐剂的处理促使鲟鱼籽酱具有更浓的腥味、青草味。     

6种鲤科鱼肌肉脂肪的脂肪酸组成比较及相关性分析

为研究鲤科鱼肌肉脂肪中脂肪酸组成及含量的差异,以鳙鱼、缩骨鳙鱼、翘嘴红鲌、鲢鱼、青鱼和脆肉鲩6种鲤科鱼为研究对象,利用气相色谱-质谱联用仪(GC-MS)测定其肌肉脂肪的脂肪酸组成及含量,再采用IBM SPSS Statistics 22. 0对各脂肪酸组成进行相关性分析和聚类分析。结果表明:6种鲤科鱼肌肉脂肪的饱和脂肪酸(SFA)含量为23. 83%～36. 35%,单不饱和脂肪酸(MUFA)含量为30. 87%～54. 34%,多不饱和脂肪酸(PUFA)含量为17. 92%～35. 07%,C20∶5+C22∶6(EPA+DHA)含量为0. 58%～16. 27%;主要组分间的相关性分析结果表明,C18∶0与EPA呈极显著正相关(相关系数r=0. 900～1. 000),EPA与DHA呈显著正相关(r=0. 800～0. 899),C18∶1与DHA呈极显著负相关,与EPA呈显著负相关;聚类分析将6种鲤科鱼分为2组,第一组为缩骨鳙鱼、翘嘴红鲌、青鱼和脆肉鲩,第二组为鳙鱼和鲢鱼。6种鲤科鱼肌肉脂肪中均含有较多的不饱和脂肪酸,具有较高的营养价值和开发利用潜力。     

鲍鱼及其副产物综合加工利用研究进展

鲍鱼作为海珍品深受国内外广大消费者的喜爱。随着养殖技术的日益成熟和养殖产量的不断增长,中国已成为世界第一鲍鱼养殖和消费国家。为提高鲍鱼产品原料利用率和产品附加值,鲍鱼加工技术也逐渐向综合利用和高新技术方向发展。本文综述鲍鱼肉的加工利用现状（干鲍、冻鲍、鲍鱼罐头）,并对其加工工艺进行具体介绍;同时综述鲍鱼加工下脚料（内脏）及鲍鱼壳的高值化开发利用现状,并对鲍鱼综合加工与利用前景进行展望,旨在为鲍鱼的进一步开发利用提供参考。     

Transforming the fermented fish landscape: Microbiota enable novel,safe, flavorful,and healthy products for modern consumers

Regular consumption of fish promotes sustainable health while reducing negative environmental impacts. Fermentation has long been used for preserving perishable foods, including fish. Fermented fish products are popular consumer foods of historical and cultural significance owing to their abundant essential nutrients and distinct flavor. This review discusses the recent scientific progress on fermented fish, especially the involved flavor formation processes, microbial metabolic activities, and interconnected biochemical pathways (e.g., enzymatic/non-enzymatic reactions associated with lipids, proteins, and their interactions). The multiple roles of fermentation in preservation of fish, development of desirable flavors, and production of health-promoting nutrients and bioactive substances are also discussed. Finally, prospects for further studies on fermented fish are proposed, including the need of monitoring microorganisms, along with the precise control of a fermentation process to transform the traditional fermented fish to novel, flavorful, healthy, and affordable products for modern consumers. Microbial-enabled innovative fermented fish products that consider both flavor and health benefits are expected to become a significant segment in global food markets. The integration of multi-omics technologies, biotechnology-based approaches (including synthetic biology and metabolic engineering) and sensory and consumer sciences, is crucial for technological innovations related to fermented fish. The findings of this review will provide guidance on future development of new or improved fermented fish products through regulating microbial metabolic processes and enzymatic activities.     

高精度双线圈式磨粒传感器的设计及研究

提出了一种可检测电感和电阻参数的高精度双线圈式磨粒传感器,其可对液压油污染物的检测提供技术支持.激励硅钢片和内置硅钢片通过磁化作用以及对磁场的聚集作用在检测区域中生成了高强度磁场,从而提升了传感器的检测精度.正方形检测通道的设计充分利用了两电感线圈之间的区域,提高了传感器的检测通量.试验表明,内置硅钢片不会改变磨粒传感器的信号噪声,有助于获取更优的信噪比.并且激励硅钢片和内置硅钢片对置区域的磁场强度最强,金属颗粒通过该区域时就会产生电感和电阻变化的脉冲峰值.在搭建的测量系统对油液中的金属磨粒进行检测试验,结果表明电感参数能够检测到25 μm铁颗粒和100 μm铜颗粒,电阻参数方式可检测35 μm铁颗粒和85 μm铜颗粒.通过结合电感参数检测结果和电阻参数检测结果,磨粒传感器可实现对25 μm铁颗粒和85 μm铜颗粒的区分检测.