1)  acoustic attenuation coefficient
声衰减系数
2)  ultrasonic attenuation coefficient
超声衰减系数
1.
Methods The ultrasonic attenuation coefficient and the ultrasonic speed of series of micro-sized composite materials have been detected,compared and analyzed.
方法分别对不同系列样品的超声衰减系数及声速进行测量、比对分析。
3)  Ultrasonic attenuation
超声衰减
1.
Pulse-echo based ultrasonic attenuation model for porosity test of carbon fiber composites;
碳纤维复合材料孔隙率的脉冲反射法超声衰减测试模型
2.
Ultrasonic attenuation coefficient of the spray-atomized and co-deposited 6061Al/SiCp composite;
用超声衰减法研究喷射沉积6061Al/SiCp复合材料的阻尼性能
3.
Ultrasonic attenuation technique is used to investigate a method to measure mass concentration of paper fibers in dilute pulp suspensions.
采用超声衰减技术研究了稀释纸浆悬浮液中纸纤维质量浓度的测量方法,讨论了稀释纸浆悬浮液中超声的衰减机理。
4)  sound attenuation
声衰减
1.
The effects of salts(KCl,NaCl,NaBr) dissolved in solution on the sound attenuation of water-soluble polymers in the process of dissolving at different frequency were studied in details.
详细研究了不同频率下水溶性高分子溶解过程中可溶盐(KC l、N aC l、N aB r)及EDTA对其声衰减效果的影响。
2.
In this paper, emphasis was paid to studying effects on the underwater sound attenuation of gradient polymer solutions.
文中详细研究了梯度高分子溶液在不同频率下,聚合物厚度及梯度结构的变化对反射声衰减效果的影响。
3.
The acoustical properties and specific heat of sample at low temperatures were studied, and the temperature dependences of modulus, sound attenuation and specific heat were obtained.
对其低温的声学和比热容性质进行了研究,得到了样品模量和声衰减以及随温度变化的规律。
5)  noise attenuation
噪声衰减
1.
Coniferous forest and evergreen broad-leaved forest had the best reduction effects and their noise attenuation values were also more 10dB.
针叶树林和常绿阔叶树林的减噪效果最好,噪声衰减值均大于10 dB;植物群落对噪声的减弱效果明显优于空旷地;建群种相同、林下层次多、植物种类丰富的群落对噪声的衰减效果优于林下无植被的群落;以落叶植物为优势种的群落在生长期对噪声的衰减值比落叶期高4~5 dB。
2.
The improved farmer algorithm optimizes the structure of original farmer algorithm,simplifying and improving the validity of noise attenuation.
通过对混有噪声的Henon序列进行仿真实验,仿真结果显示,改进后的Farm er算法能够提高噪声衰减的精度,降低与理想Henon序列的绝对误差。
3.
This paper discusses 4 types of processing methods: time-spatial domain frequency splitting random noise attenuation, frequency-spatial domain coherent noise attenuation, waveform match processing and gather data fitting 3-D random noise attenuation.
首先对资料的质量进行了分析,由于是拼接资料,因此存在着能量不均衡、覆盖次数不均匀、波形不一致以及各类干扰发育等问题;然后针对这些问题研究了时间-空间域内分频随机噪声衰减、频率-空间域相干噪声衰减、波形匹配处理和数据拟合三维随机噪声衰减等4种处理方法,分别取得了很好的处理效果。
6)  acoustic attenuation
声衰减
1.
Megahertz acoustic attenuation in fluidized mud;
浑水中兆赫频率的声衰减实验研究
2.
Seabed sediment acoustic attenuation in shallow seas of the South China Sea;
南海浅海海底沉积物的声衰减
3.
Influences of granule factor of seabed sediments on acoustic attenuation under different frequencies;
海底沉积物颗粒因素在不同频率下对声衰减的影响
参考词条
补充资料:电离辐射衰减系数


电离辐射衰减系数
ionizing radiation attenuation coefficient

式中/0为没有防护层(d=0)时的电离辐射强度;I是防护层厚度为d时的电离辐射强度;刀为电离辐射衰减系数。如果d以线性厚度厘米为单位,则召以厘米一’表示。 刀是物质防护能力的度量。召值的大小取决于防护层物质的特性和电离辐射的能量。物质的月值越大,防护性能越好。物质的防护性能常用衰减倍数K表示。衰减倍数是屏蔽前的剂量D。与屏蔽后的剂量D之比,K二D0/D。将单向粒子流的辐射量减少到初始值一半时的减弱层厚度,称为半厚度,亦称半值厚度或半值层,记作心:。dlZ=住693/拜(厘米)。某些物质对早期核辐射Y射线和中子流的半厚度如表所示。 几种物质的半厚度单位:厘米卜洲扭 已知防护层厚度d和半厚度叭2,可计算其衰减倍数K: K=2脚rtllZ=2”式中n为防护层物质的半厚度数,n=d/试2。反之,为获得预定的衰减倍数K,可按公式n一InK/0.693来计算半厚度数n。根据防护层厚度斌半厚度峨:、衰减倍数K及通过防护之前的剂量D。可计算出工事内核辐射剂量D: D=几(l/酬=几K一‘ (陈冬英)dionli fushe shuaiiian xishu电离辐射衰减系数(ionizing radiationattenuation coefficient)电离辐射通过介质时强度相对变化的表征量。军事上常见的日粒子、Y光子之类的电离辐射通过物质时,它的强度近似按指数规律衰减: I=去e一召d
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