1) Damping factor alignment
衰减系数校正
2) attenuation correction
衰减校正
1.
In this paper we present a modified algorithm of CT-Based attenuation correction for PET/CT Scanners in the presence of contrast agent,which can lead to unbiased result for the estimation of emission activity in these cases.
PET/CT扫描一般直接将CT透射扫描数据用于PET发射扫描的衰减校正,但是在有口服造影剂使用的场合,常规的衰减校正算法对PET扫描结果会带来约20%的正偏差。
2.
The CT option can make attenuation correction to SPECT image or coincidence PET image, which makes the image of nuclear medicine closer to the real situation of distribution of radioactive nuclide in patients.
该CT能完成对SPECT图像或符合线路PET图像的衰减校正,使核医学图像能更接近的反映核素在人体内的真实分布情况。
3.
Some new advances of research and clinical study on PET/CT were summarized briefly,including the choice of crystals,development of CT,radiotherapy plan,attenuation correction with CT,respiratory motion and CT contrast induced artifacts.
本文简要介绍PET/CT有关的几个技术问题和临床应用方面的新进展,如晶体的选择、CT技术进展、放射治疗、衰减校正、呼吸运动及CT造影剂的影响等。
3) attenuation coefficient
衰减系数
1.
Measuring the ultrasonic attenuation coefficient of flyash scale in the transport pipeline;
输灰管灰垢声衰减系数的测定
2.
Experimental study on integrated attenuation coefficient of organic contaminant (COD_(Cr)) in upper reaches of Hanjiang River;
汉江上游有机污染物COD_(Cr)综合衰减系数的试验确定
3.
Experimental research on attenuation coefficient model of low-frequency wave in oil layer;
低频波在油层中衰减系数预测模型的实验研究
4) decay coefficient
衰减系数
1.
Based on the 2nd Lyapunov method,a notion of decay coefficient was introduced.
基于Lyapunov第二方法引入衰减系数的概念,在此基础上给出保证单个系统稳定的最小网络通讯间隔以及保证多系统同时稳定时网络通讯间隔应满足的条件。
2.
In this paper flight decay coefficient and ballistic limit of several type fragment in common use are computed and analyzed,and affection of fragment shape to velocity decay coefficient and ballistic limit is also analyzed.
文中计算比较了几种常用典型破片的飞行衰减特性及极限贯穿速度;对破片形状对速度衰减系数及弹道极限速度的影响进行了分析;提出了在战斗部结构设计时,选择破片形状应遵循的原则。
3.
The decay coefficient is introduced into showing dispersion of the copper bar.
考虑到样品(铜棒)散热,引进衰减系数,描述温度幅度随频率及传播距离的变化关系。
5) attenuation coefficient of velocity
衰减系数
1.
The experimental results show that a) the attenuation coefficient of velocity is constant and the air drag coefficient is a linear function of initial velocity.
结果表明:(1)破片长距离(120m)飞行时的衰减系数为常数,阻力系数与破片初速成线性关系;(2)在爆轰驱动下,直径为6。
2.
The experimental results show that:(1) for ideal spheres,the attenuation coefficient of velocity is constant,the air drag coefficient is slightly affected by the initial velocity and is a linear function of initial velocity,and(2) for real fragments formed by a warhead,the flight performances are different from ideal spheres,the air drag coefficient is affected by th.
实验结果表明:(1)对于理想球形钨合金破片,在同一初始速度条件下,衰减系数为常数,空气阻力系数与初始速度有关,两者成线性关系;(2)对于经历爆轰驱动的球形钨合金破片,由于有轻微的质量损失和变形,速度衰减规律与理想球形钨合金破片有明显的区别,空气阻力系数与飞行速度有关,两者成线性关系。
6) damping coefficient
衰减系数
1.
The damping rule of vibration along railway is obtained and calculation is made for damping coefficient(0.
通过实测,对这种振波的过程曲线特征进行了描述和分析,指出这种振波的振动频率,幅度范围及振动过程中的脉冲特征;并对振波在硬塑土层中的衰减特征,衰减系数等进行了论述。
2.
The experimental results indicated that the liquid surface wave amplitude declined exponentially with the spreading distance and the damping coefficient,which varied lineally with frequency,has dispersive characteristics.
实验结果表明,液体表面波的振幅随传播距离的增大而按指数型规律减小,并具有明显的色散效应,衰减系数液体表面波的随频率线性增大。
3.
Although calculated wave heights in terms of Binham fluid model theory were smaller compared with the measured characteristic value,the damping coefficients with both kinds of heights were of same order.
结果表明,计算波高小于实测值,但二者的衰减系数为同一量级。
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
说明：补充资料仅用于学习参考，请勿用于其它任何用途。
参考词条