查询词典 particle

In microbeam experiment, cells on a dish are individually irradiated by a predefined exact number of alpha particles, allowing the effects of exactly one alpha particle traversals to irradiate significant numbers of cells.

荷电粒子微束(Charged-particle Microbeam)是一种将粒子束斑的直径限制在微米量级范围内，并将预定个数的粒子注入到细胞中某一特定位置一种辐射装。。。

By applying the smoothed particle hydrodynamics method to the detonation driving plate problems, a clear wave structure in the metal plate and the varying process of the projection angle were obtained.

将光滑粒子法(smoothed particle hydrodynamics method， SPH)应用于金属平板爆轰驱动过程的数值模拟，得到了炸药与金属相互作用的清晰的图像和平板抛射角的变化。

Particle Swarm Optimization is adopted to detect parameter pattern e.g. circle, ellipse, hyperbola and asymptote.

我们采用一种以粒子群演算法Particle Swarm Optimization 为基础的方法，用来侦测一张影像上的参数图形(如：圆、椭圆、双曲线与双曲线的渐近线)的参数。

It and the proton form nearly the entire mass of atomic nuclei. See table at subatomic particle

它和质子几乎构成了整个原子核的质量参见 subatomic particle

The 20S catalytic core of the 26S proteasome has the shape of a barrel made of four rings which are composed of seven differentαsubunitsα_1-α_7 at two outer rings and seven differentβsubunitsβ_1-β_7 at two inner rings at which the catalytic sites locate. Three of theβsubunits contain proteolyses sites, which are sequestered in the hollow interior of the 20S particle. Substrates enter the 20S through a narrow channel formed by theβsubunits, whose N-termini, depending on their conformation, can either obstruct or allow substrate entry and thus function as a gate. This entry channel is narrow and only permits passage of unfolded, linearized polypeptides.

哺乳动物26S蛋白酶体是由一个20S催化颗粒(catalytic particle，CP)和两个19S调节颗粒(regulatory particle，RP)组成的ATP(adenosine-triphosphate，ATP)依赖性蛋白水解酶复合体。20S CP是26S蛋白酶体的催化核心，它是由4个圆环堆叠形成的桶状复合物，其中两侧外环每个环是由α_1-α_7亚基组成，两个内环每个环是由β_1-β_7亚基组成，4个环的中央形成一个狭窄的内腔。2个β内环形成了20S CP的催化中心空腔，其内壁为催化活性位点所在地；外侧α环中心的孔道是底物到达催化中心空腔的通道，一般被α亚基上的N末端所封闭，阻止胞内非目的靶蛋白进入20S CP内被降解破坏。

The main research work of this paper are focused on following areas:(1) Based on review of the theory and methods on measurements of particle fields, a new idea for obtaining particle size and velocity distribution within a spray through imaging the particle field with a laser light sheet was put forward;(2) A DPIV (Digital Particle Image Velocimetry) system, is fit for velocity measurements of low speed flows, was developed and expended to particle size distribution measurement;(3) An arithmetic for particle velocity field reconstruction was developed, and the velocity distribution of water mist was also obtained;(4) A software system for particle analysis, which based on image geometry emend, de-noise and image partition was developed, the parameters such as particle size distribution, mean diameter, number of particles, minimum and maximum diameter can be got with this system;(5) A water mist system was developed and its characteristics, such as droplet velocity, size distribution, number of droplets and spray cone angle under different conditions were obtained from experiments with PIVS;(6) The measurement results of water mist characteristics with PIVS were compared and analyzed with the simply simulated results, and in addition, in order to verify the accuracy of PIVS, some experiments were conducted with the standard particles, such as glass-ball with known mean diameter of 50μm and 115μm, metallic coated tracing particle with mean diameter of 12μm;(7) Some experimental studies on interaction of water mist with liquid pool fires were conducted.

本论文的主要工作包括以下几个方面：（1）在对粒子场测量的相关理论和具体方法进行综述分析的基础上，提出了通过采用激光片光对粒子场进行成像以获取其粒径和速度等参数分布的新思路；（2）研制了适宜于低速流动速度场测量的DPIV(Digital Particle Image Velocimetry)系统，并使其实现了对粒子场粒径分布的测量功能；（3）研制了基于粒子运动轨迹的速度场重建算法，获取了细水雾雾场的速度分布；（4）研制了基于几何校正、去噪、图象分割等图象处理方法的"粒度分析软件系统"，该系统既可分析给出粒子场的粒径分布直方图和平均粒径，还可给出粒子的数目以及最大、最小粒径等信息；（5）建立了一细水雾发生系统，并应用上述方法对不同压力条件下细水雾系统的雾场特性（如速度分布、雾滴粒径分布、雾滴的数目、喷雾张角以及雾化长度等）进行了实验测量研究；（6）对细水雾特性参数的PIVS测量结果与计算机简单模拟计算结果进行了定性比较分析，并利用平均粒径为50μm和115μm的玻璃球以及12μm的标准示踪粒子对PIVS系统的粒径和速度测量结果进行了实验验证，同时对其局限性进行了分析讨论；（7）对不同工况条件下细水雾与油池火相互作用的过程进行了模拟实验研究。

In: Proceedings of the 1999 Congress on Evolutionary Computation, Piscataway, NJ: IEEE Press, 1999: 1958~1962.[9] Kennedy J. Small worlds and Mega-minds: effects of neighborhood topology on particle swarm performance. In: Proceedings Congress on Evolutionary Computation, Piscataway, NJ: IEEE Press, 1999: 1931~1938.[10] Peram T, Veeramachaneni K, Mohan C K. Fitness-distance-ratio based particle swarm optimization.

近来性能较为显著的基于PSO算法的改进算法有Thanmaya Peram[10]等人于2003年提出的基于粒子群优化的适应值-距离-比例算法(Fitness-Distance-Ratio based Particle Swarm Optimization， FDR-PSO)，在此算法中每个粒子根据一定的适应值-距离-比例原则，向附近具有较好适应值的多个粒子进行不同程度的靠近，而不仅仅只向当前所发现的最好粒子靠近。

In this paper, the sorting of wear, the mechanics of wear particle formed and the characteristics of wear particles are introduced, and morphology characteristics parameter of wear particle are determined, which is particle brim digital feature. Based on image characters, after pre-process, section and extracting of contour parameter of wear particle using image process technique, four shape character parameters are extracted by fourier series expansion. After analyzing fundamental principle and shortcomings of neural network, current BP algorithm is improved in output optimization, network linearization implication optimization and adding momentum, and then astringe speed of BP algorithm.

本文介绍了磨损的分类以及磨粒的生成机理、磨粒的形态特征，应用摩擦学系统分析的观点，确定磨粒边缘数字特征为磨粒的识别特征参数；根据磨粒图像的特征，利用计算机图像处理技术对磨粒图像进行预处理、分割、轮廓参数的提取，采用傅立叶级数展开式提取磨粒四个形状特征参数：圆形度、散射度、凹度、细长度；针对 BP(Back-Propagation)神经网络收敛速度慢的特点，对现行的 BP 算法进行改进，并通过实验验证改进后的网络收敛速度快；研究设计了磨粒图像采集系统；利用 BP 算法建立磨损磨粒自动识别算法模型 AWPRM(Auto Wear Particle Recognition Model)。

To avoid the prematurity phenomenon of particle swarm optimization, a novel hybrid genetic particle swarm optimization algorithm is proposed. An eliminative mechanism is introduced into the iteration of PSO.

针对粒子群算法容易出现&早熟&的缺点，提出了一种改进的混合遗传粒子群(hybrid genetic particle swarm optimization， HGPSO)算法。

Firstly, on the basis of defining the characteristics of project and reviewing the mathematical models for RCPSP, we constructed the mathematical model for RCPSP under the condition that there is non-fixed duration and splittable tasks in project; In order to solve above model, we emphatically discussed the basic principle of the swarm intelligence algorithm--the particle swarm optimization algorithm as well as improvement research for current algorithm, and then proposed a new improved particle swarm optimization algorithm and analyzed its application process in the resource-constrained project scheduling problem; Lastly, in order to confirm the validity of the model and the algorithm, we took an experiment based on 108 instances that produced by problem instance generator which was developed by our team.

首先，在对RCPSP项目特征进行界定以及对项目进度优化模型回顾的基础之上，构建了基于活动工期不固定、任务可拆分特征的RCPSP的数学模型；为了求解上述模型，本文详细阐述粒子群优化算法(Particle Swarm Optimization，PSO)的基本原理以及当前对其改进的研究成果，提出了一种新的改进PSO算法，并对其在RCPSP的应用过程进行了设计；最后，为了检验模型的有效性及算法的优越性，基于梯队内部开发的案例生成器生成的108个算例，进行了仿真试验。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。