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中国科学院声学研究人员揭示高频Lamb波在微尺度薄板中的传播特征（图）
尺度结构 力学性能 纳米
2024/4/18
当微尺度结构的特征尺寸减小到微纳米量级时，材料的力学性能对特征尺寸的变化非常敏感，受这种尺度效应影响，Lamb波在微尺度板中的传播特性与宏观尺度不同。研究微尺度板中Lamb波的频散及模态位移特征，有助于分析导波的可激发性、可探测性及波泄漏特点，可为导波无损检测技术提供理论指导。
日前，北京大学地球与空间科学学院理论与应用地球物理研究所张海明副教授与其弟子冯禧博士合著的《地震学中的Lamb问题（下）》由科学出版社出版。
该品种具有抗松材线虫病和含β-蒎烯高的优良特性，春稍、秋梢呈现2针、3针轴向交替形态，树干通直，生长迅速，3年生时树高和胸径较群体平均值提高60.17%和25.63%。适宜种植的区域为浙江、福建、江西、湖北、湖南、四川、重庆、贵州、广东、广西、安徽等适宜栽种马尾松的区域。
Monthly Dynamical Patterns of Nitrogen and Phosphorus Resorption Efficiencies and C:N:P Stoichiometric Ratios in Castanopsis carlesii (Hemsl.) Hayata and Cunninghamia lanceolata (Lamb.) Hook. Plantations
nutrient reuse strategy nutrient limitation ecological stoichiometric ratios mature and senescent leaves subtropical forest plantation
2023/12/1
Trees can resorb nutrients to preserve and reuse them before leaves fall, which could efficiently adapt to environmental changes. However, the nutrient requirements of trees in different months with s...
在地震动数值模拟方法中，谱元法和有限元法是应用较广泛的两种方法。基于经典的Lamb问题模型，首先推导给出地表竖向位移的解析解答。然后分别利用常用的四阶谱元法和线性有限元法，模拟了地表脉冲力源作用下模型的位移响应。考虑有意义的最短波长内的采样点个数及单元高宽比的变化，对比了两种方法的模拟精度；结果表明：对于谱元法，观测点与波源之间需至少包含两个网格，在此条件下，最短波长内包含一个网格（最短波长内5个...
采用ANSYS有限元仿真软件模拟超声Lamb波在4 mm厚的钢板结构中的传播过程，计算S0模态和A0模态超声Lamb波的群速度和沿钢板厚度方向上的位移波结构，绘制频散曲线和波结构特性曲线，理论分析与仿真结果基本吻合；为超声Lamb波群速度测定和缺陷检测提供理论依据。
薄膜谐振Lamb波传感器测量液体流速矢量的方法
薄膜谐振型Lamb波传感器 消逝波 反对称模式 流速矢量测量
2017/2/27
针对液体流速测量领域中微型流量传感器高品质因数、高灵敏度的性能要求。本文设计一种双端增强型薄膜谐振结构实现Lamb波传感器的高品质因数，利用传感器反对称模式（A01模式）在薄膜-液体界面处的消逝波实现液体流速矢量测量。所制作的双端增强型薄膜谐振Lamb传感器A01模式的主峰品质因数为703，A01模式的频率移动量与液体流速大小存在线性关系，频率移动方向与液体流动方向存在对应关系。流速实测灵敏度约为...
Effect of olive cake on daily gain, carcass characteristics and chemical composition of lamb meat
olive cake Pramenka lambs fattening carcass traits meat chemical composition
2015/6/4
This experiment investigated the effect of olive cake in the feed of weaned Pramenka lambs on their daily gain, carcass traits and on the chemical composition of different groups of muscles. For that ...
Effect of weaning system on lamb growth and commercial milk production of Awassi dairy sheep
Awassi sheep lamb growth milk yield restricted suckling
2015/6/4
To determine the effect of weaning system on Awassi sheep milk production and lamb growth, 68 Awassi ewes and their lambs (n = 104) were assigned to one of the following treatment groups a) after 3 da...
Breeding for sustainability: Effect of breed on cultural energy expenditure of lamb production
cultural energy sustainability breed, sheep Texel Columbia Suffolk
2015/6/2
Two-year data from terminal study conducted to evaluate post-weaning growth and carcass traits of Texel, Suffolk and Columbia sired offspring were used to evaluate the effect of breed on cultural ener...
Lamb Production Costs: Analyses of Composition and Elasticities Analysis of Lamb Production Costs
Elasticity Lamb Production Cost Production System Technical Indicator
2016/5/18
Since lamb is a commodity, producers cannot control the price of the product they sell. Therefore, managing production costs is a necessity. We explored the study of elasticities as a tool for basing ...
Effects of Dietary Lycopene Supplementation on Plasma Lipid Profile, Lipid Peroxidation and Antioxidant Defense System in Feedlot Bamei Lamb
Lycopene Plasma Lipid Profile Antioxidant Enzymes Malondialdehyde Lamb
2016/5/18
Lycopene, a red non-provitamin A carotenoid, mainly presenting in tomato and tomato byproducts, has the highest antioxidant activity among carotenoids because of its high number of conjugated double b...
Antibacterial potential of lactobacilli isolated from a lamb
Lactobacillus spp. antibacterial activity probiotics cell-free supernatants
2015/4/15
The antimicrobial properties of three potential probiotic strains of lactobacilli isolated from a lamb (Lactobacillus murinus C, Lactobacillus mucosae D and Lactobacillus reuteri E) were studied using...
Quantitative methods to determine factors affecting profits of lamb fattening enterprises
meat production profitability regression function
2015/1/28
The purpose of this study was to demonstrate the use of profit function regression model as a possible practical decision support tool in the lamb meat production. It was found that all independents v...