粒子

In the CVB-PIV system,the image of astatic particle reflection is a circle,whose center represents the in-plane position of the particle andradius is equal to the displacement of bias related to the out-plane position of the particle.

同时，通过CVB-PIV对单个或多个粒子的静止、直线运动、摆动和圆周运动的研究，以及对平面镜角速度等参数对于粒子影像的影响和粒子面外位置与粒子影像偏移量对应关系的探讨表明，静止粒子的影像是一个圆，圆心坐标与粒子的面内位置相对应，圆的半径就是粒子影像的偏移量，与粒子的面外位置一一对应。

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。

Based on the model of DLA, this paper simulates the process of aggregation's growth for random walk particles from local area on two-dimension Euclidean plane. The aggregation is confined to Euclidean circular plane for large enough particle walking area and far enough partial source distance. The centre of the Euclidean circular plane is on the line between the particle source's symmetric centre and the seed particle, and is more closer to the particle source than the seed particle. Though the rate of aggregation growth is different in different directions, the whole aggregation shows fractal structure.

以DLA模型为基础，模拟研究了在二维欧几里德平面上由局部区域内产生随机运动粒子的聚集生长过程，发现对于足够大的粒子运动区域和足够远的粒子源距离，凝聚集团大体上被限制在欧氏圆形面内，圆心在粒子源对称中心和种粒子的连线上，且比种粒子更加接近粒子源；凝聚集团朝各个方向的平均生长速率虽然不同，但整体仍呈分形结构。

In order to seamlessly combine NSGA-Ⅱ and the greatly different MOPSO, the special concepts (particle and its velocity, Pbest and leader) for MOPSO were dealt with within the scope of NSGA-Ⅱ: 1 particle in MOPSO was considered to be equivalent to offspring individual in NSGA-Ⅱ; 2 the concept of velocity fell into disuse; 3 the concept of Pbest also came into disuse. Instead of that, for each dimension of a particle, the nearest one among its nondominated individuals in parent population was used; 4 the leader of a particle was the individual with largest sparse degree among parent population or selected from parent population by binary tournament selection method, which of them taking effect lies on the predefined probability. In addition, a new concept, i.

为使这两种差异较大的算法实现无缝融合，在NSGA-Ⅱ算法范围内对MOPSO中特有的概念粒子及其速度、Pbest、引导者进行处理：1粒子对应于NSCA-Ⅱ中子代群体的个体；2不再使用粒子速度概念；3不再使用粒子Pbest概念，代之以从父代群体中为每个粒子的每一维寻找一个最近的该粒子非支配个体；4每一个粒子的引导者可以是父代群体中稀疏程度最大的个体或者是按照二进制随机竞赛选择方法从父代群体中选择的一个个体，具体哪一种方式发挥作用依赖于预先设定的概率。

The results show that:(1)Parameters of solid particles are the main factors influencing the measurement results.(2) In the study of gas-solid phase flow by PDA, it is necessary to choose the regular and unliable to conglomerate particles with high refracti...

试验过程中，运用几种不同的粒子作为煤粉粒子的模拟粒子进行测量和比较，结果表明：（1）粒子的特性参数是影响测量精度的重要因素之一；（2）测最气固两相湍流流场中粒子的运动特征时，应尽可能选择形状较规则、折射率大、尺寸分布合理、不易粘结且易于收集同时接近所要模拟的粒子性能的固体粒子，必要的时侯应结合粒子性能对测量结果进行修正。

In order to preserve the varieties of the swarm and avoid to be in premature convergence,a Particle Swarm Optimization algorithm based on the differential evolution mutation is proposed.The new algorithm uses the particle aggregation quality to judge that if the particles in the swarm are congregative so much,then apply the differential evolution to mutate the self prevenient best position of each particle,in order to realize the aim of preserving the varieties of the swarm.

为了保持粒子种群的多样性而避免发生&早熟&的问题，提出一种基于差异演化变异的粒子群优化算法，该方法通过粒子聚集性判断如果粒子群中的粒子过于聚集，则使用差异演化算法对PSO算法中各个粒子的自身历史最佳位置进行变异，以实现保持粒子群种群多样性的目的。

According to the characteristic of silver nanoparticles, their uniform dispersion in reaction media was obtained by surface modification, ultrasonic radiation and the select of emulsion, and then emulsion polymerization system were formed by combination with reactive monomer and initiator. Nano-Ag/Polystyrene core-shell particles were prepared by emulsion polymerization and their microstructure were characterized by TEM, FTIR, XPS, AFM and TG/DTA. The experimental results showed that silver nanoparticles were coated by polymer and the composite particles had typical core/shell structure, and the microlevel combination was realized. Meantime, the form mechanism of nano-Ag/polystyrene core-shell particles was tentatively researched. The conclusion is that the perfect coating was able to obtained by the control of reaction condition.

根据纳米银粒子的特性，借助于表面处理、超声辐照以及乳化剂的选择，使其均匀分散在反应介质中，再与反应单体、引发剂等形成乳液聚合体系；采用乳液聚合方法、包裹聚合方式，制备出纳米银/聚苯乙烯核壳复合粒子，并借助于TEM、FTIR、 XPS、AFM、TG/DTA等分析手段对复合粒子微观结构进行了表征；结果表明：纳米银粒子表面被聚合物层包覆，复合粒子呈明显的核壳结构，实现了微观尺度上的复合；同时，初步探讨了纳米银/聚苯乙烯核壳复合粒子的形成机理，指出：通过控制反应条件，可以使形成纳米银/聚苯乙烯核壳复合粒子的聚合反应方式占主导地位，实现最大限度地包覆。

FeSi nanoparticles were synthesized via thermal decomposition of iron pentacarbonyl in the solution of dioctyl ether, stabilizers oleic acid and oleylamine. The TEM images showed that FeSi nanoparticles had cubic shape, but it seemed that the composition was not uniform. According to the EDS results, the Fe:Si ratio of gray-uniform nanopaiticles was almost 1:1, and blacker FeSi nanoparticles contained more Fe atoms. Although FeSi didn't have uniform structure, it still could be proved that the incorporation of Fe and Si existed in a single nanoparticle. All possible structure, lattice, binding, morphology, surface condition would be discussed. These results indicated that perhaps FeSi2 was the main structure of the new products; however, due to incompletely combination and less synthesized time, it might still contain some part of Si and Fe structure. Besides, FeSi nanoparticles preserved the optical properties from Si atoms, but the PL intensity was much lower. The maxima PL peak appeared at 388 nm with the excitation at 300 nm. Their saturation magnetization, remanent magnetization and coercivity were measured by the SQUID, exhibiting their nearly superparamagnetic behavior.

利用热裂解系统可成功将研磨矽奈米粒子及五羰铁结合，制备出铁矽奈米粒子；从穿透式显微镜照片可知其粒子呈现立方体型态，但颜色深浅及组成不均，EDS结果则显示颜色均匀之粒子铁与矽之组成大致为1：1，颜色较深之粒子则含有较高量的铁元素；尽管组成比例并不统一，但单颗粒子同时含有矽与铁两种元素，初步说明铁矽奈米粒子之形成；进行多种结构与表面分析并探讨所有可能之键结、结构及表面元素后，推测铁矽奈米粒子可能以FeSi2之结构形成，并同时包含未重组完成的矽及铁之结构；利用PL分析得知铁矽奈米粒子确实保留矽之放光特性，并在300 nm激发光源下，於波长388 nm处有一最强放光特性峰，但整体发光效益不及研磨矽奈米粒子之结果；最后，利用超导量子干涉磁化仪量测其饱和磁化量、残留磁化量、与矫顽磁力，发现磁滞现象并不明显而几乎呈超顺磁性。

125I seeds interstitial brachytherapy is a new kind of method to treat with malignant tumors. The aim of the experimental research through animals is to investigate the therapeutic effect and the pathological changes on rabbits' VX_2 liver tumor treated with ~(125)I seeds interstitial brachytherapy and percutaneous ethanol injection under CT guidance. We aim to identify the therapeutic effect and the criterion of ~(125)I seeds radiant activity selection, optimize the therapeutic regimen, investigate the tissue damage, its' prothetic time and the relationship between time and dosage effect, and approach to provide fundamental theories for ~(125)I seeds clinical using and arrive at the best dosage range of ~(125)I seeds interstitial brachytherapy. And it can become a new and effective kind of therapies to be applied for the clinical treatment to mid-advanced stage and recurring liver tumor.

放射性粒子组织间植入是肿瘤治疗的一种新方法，本研究通过动物实验探讨CT导引下瘤体内~(125)I粒子植入治疗，以及~(125)I粒子组织间植入联合经皮乙醇注射综合治疗兔VX_2肝转移癌的疗效及其病理基础，确证~(125)I粒子组织间植入治疗肝癌的有效性，确定治疗高度恶性肿瘤的粒子选用标准和最佳治疗方案，同时探索~(125)I粒子在家兔肝脏组织间植入内照射后放射损伤和修复的变化及其时间与剂量效应的关系，提出临床应用~(125)I粒子组织间植入治疗的最佳剂量范围，为该疗法在实际应用中合理化治疗方案的取得提供理论依据，并为临床中晚期及复发肝癌的治疗提供一种新颖、有效的手段。

The encapsulated TiO〓 particles by polymer were obtained with soapless emulsion polymerization of methyl methacrylate in water in the presence of the pretreated TiO〓 particles.

一种是用偶联剂钛酸丁酯对亲水性TiO〓粒子进行预处理，钛酸丁酯与TiO〓表面羟基反应，交联到TiO〓粒子表面，使TiO〓粒子表面由亲水性转变为憎水性，改善无机粉体与有机单体的亲合性，再进行TiO〓存在下甲基丙烯酸甲酯的无皂乳液聚合，即可得到TiO〓-PMMA复合粒子：另一种方法是用表面活性剂对TiO〓进行预处理，再进行TiO〓粒子存在下甲基丙烯酸甲酯的无皂乳液聚合，TiO〓粒子表面可形成一层均匀的聚合物膜，提出了包覆机理，指出单体在无机粉体表面发生聚合的关键是预先在粒子表面形成聚合场所，即吸附一层表面活性剂。

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。