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根据电介质极化理论,研究了在施加电场的条件下,气溶胶粒子的极化,作用在极化粒子上的感应力矩和感应力,以及极化粒子间的相线作用能,继而深入探讨了极化气溶胶粒子的凝并行为机理。 相似文献
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气溶胶力学是一门新兴的交叉学科,具有广泛的应用前景。自Fuchs建立了气溶胶力学以后,该学科已从孤粒子动力学阶段发展到多粒子相互作用下的动力学阶段。本文总结该学科的发展历程,重点对许多工业生产中有重要应用价值的气溶胶粒子的沉降与气溶胶粒子的碰并(即聚集、团聚、聚沉、凝并)进行讨论。 相似文献
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利用2005年10月20日在河北省石家庄和邯郸地区进行的一次飞机探测资料,初步分析了石家庄和邯郸上空的气溶胶粒子数浓度、粒径、粒子谱垂直分布特征,对石家庄与邯郸之间的水平飞行气溶胶粒子数浓度资料进行分析,并对石家庄、邯郸的气溶胶粒子谱进行函数拟合。结果表明:各高度层气溶胶粒子数浓度基本上都是石家庄高于邯郸,各高度层粒子平均直径基本上都是石家庄低于邯郸。两地气溶胶粒子数浓度、粒子平均直径随高度的分布有不同特点。石家庄、邯郸气溶胶粒子谱谱型,低层相似,基本都是单调下降,高层粒子谱谱型为多峰型。3100m高度层粒子数浓度在水平方向上分布不均匀,城市附近上空气溶胶粒子数浓度相对较大,郊县气溶胶粒子数浓度相对较小。随着高度增加,粒子数浓度减小,水平方向的绝对变化越来越小。利用幂函数N(D)=AD-B可以对不同高度气溶胶粒子谱进行较好的拟合。 相似文献
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沙尘和灰霾天气下毛乌素沙漠地区大气气溶胶的光学特征 总被引:6,自引:0,他引:6
利用AERONET榆林站点的数据比较分析了在沙尘和灰霾两种不同天气条件下毛乌素沙漠边缘地区大气气溶胶的光学和物理特性。分析的主要内容包括:气溶胶光学厚度、单次散射反照率、复折射指数、不对称因子、气溶胶粒子的粒度分布、Angstrom波长指数、体积浓度、气溶胶粒子半径等光学和物理参数。分析结果表明,榆林地区大气气溶胶光学特性主要是受到沙尘和人为气溶胶的共同影响。在沙尘天气和灰霾天气下,大气气溶胶的光学特性有显著的差异。 相似文献
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用高频感应加热法在Ar气氛中制备了Zn超细颗粒,利用透射电镜、X-射线衍射仪、X-电子能谱议、红外谱仪及差示扫描术研究了颗粒的形态、晶体结构、表面组成、光吸收及颗粒的热稳定性。结果表明.颗粒形状大部分为六边形,也有少量立方形,晶体结构与块材Zn相同,在紫外及可见光部分有很强的先吸收,而在红外吸收谱上的一个吸收峰可能是表面氧化层表面声子吸收所致。在室温下,颗粒是稳定的,但在高温下,由于表面吸附的氧而发生了氧化过程。 相似文献
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超细晶1.73C超高碳钢的组织和性能 总被引:1,自引:0,他引:1
将1.73C%超高碳钢(UHCS-1.73C)的钢锭经过低应变、多道次锻造,加热淬火、高温回火后得到超细晶粒、球状碳化物组织,再进行循环感应热处理,得到超细晶粒马氏体基体上分布超细球状碳化物的组织,研究其组织和性能与循环感应热处理之间的关系.结果表明,随着感应加热淬火循环次数增加,组织中出现板条马氏体且数量增加,马氏体片变短、钝化,碳化物颗粒更圆整,压缩屈服强度升高,塑性增大.循环感应淬火4次后(不回火)屈服强度1105MPa,断裂强度1992MPa,压缩率9.8%. 相似文献
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基于链化分析的磁流变弹性体剪切模量模型 总被引:2,自引:1,他引:1
磁流变弹性体是一种磁流变材料,由高分子橡胶基体掺杂微米级的铁磁性颗粒固化而成.基于磁性物理学理论,从磁流变弹性体在磁场作用下铁磁性固体颗粒极化成链的微观结构出发,探讨磁流变流体中固体颗粒间的相互作用机理,分析研究颗粒间的相互作用力,建立了一种微观力学模型,可用于分析磁流变流体在外加磁场作用下剪切模量及其影响因素的作用效果,揭示磁流变效应的微结构机理,为磁流变弹性体的性能优化、工程开发及应用提供理论依据. 相似文献
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A comparison is presented of the effects of particle size, concentration, and detector depth on side scattering for linearly and circularly polarized incident light. The scattering medium consists of various concentrations of particles, which are either 1.24, 0.494, 0.36, 0.123, or 0.065 μm in diameter, and which were mixed into filtered, distilled water and serve as the scattering centers. The results indicate that when this scattering medium is irradiated with linearly polarized laser light whose beam has been put through a quarter-wave plate in an effort to produce circularly polarized light, then there are two components scattered 90°, that is, circularly and linearly polarized light. The amount of each component and the ratio to total intensity of scattered light are analyzed for the different particles. 相似文献
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Xin Zhang Haoxuan Ding Shu Yang Hualin Yang Xiaoqing Yang Bosheng Li Xueting Xing Yaojie Sun Guangxin Gu Xiaorui Chen Jianzhi Gao Minghu Pan Lifeng Chi Quanmin Guo 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(17):2207111
Chirality transfer is of vital importance that dominates the structure and functionality of biological systems and living matters. External physical stimulations, e.g. polarized light and mechanical forces, can trigger the chirality symmetry breaking, leading to the appearance of the enantiomeric entities created from a chiral self-assembly of achiral molecule. Here, several 2D assemblies with different chirality, synthesized on Au(111) surface by using achiral building blocks – glycylglycine (digly), the simplest polypeptide are reported. By delicately tuning the kinetic factors, i.e., one-step slow/rapid deposition, or stepwise slow deposition with mild annealing, achiral square hydrogen-bond organic frameworks (HOF), homochiral rhombic HOF and racemic rectangular assembly are achieved, respectively. Chirality induction and related symmetry broken in assemblies are introduced by the handedness (H-bond configurations in principle) of the assembled motifs and then amplified to the entire assemblies via the interaction between motifs. The results show that the chirality transfer and induction of biological assemblies can be tuned by altering the kinetic factors instead of applying external forces, which may offer an in-depth understanding and practical approach to peptide chiral assembly on the surfaces and can further facilitate the design of desired complex biomolecular superstructures. 相似文献
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Light scattered from optically active spheres was theoretically analyzed for biodetection. The circularly polarized signal of near-forward scattering from circularly dichroic spheres was calculated. Both remote and point biodetection were considered. The analysis included the effect of a circular aperture and beam block at the detector. If the incident light is linearly polarized, a false signal would limit the sensitivity of the biodetector. If the incident light is randomly polarized, shot noise would limit the sensitivity. Suggested improvements to current techniques include a beam block, precise angular measurements, randomly polarized light, index-matching fluid, and larger apertures for large particles. 相似文献
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V. L. Popov 《Technical Physics Letters》2002,28(5):385-390
The motion of a system of several bodies linked by bonds of variable length in a spatially periodic potential is studied. It is shown that quasistatic periodic variations of the system parameters in time can induce translational motion of the system in the absence of directed external forces, or motion in the direction opposite to that of an external force. To provide for the possibility of the induced translational motion, the system parameters (e.g., bond lengths) must vary in the space of these parameters according to closed trajectories containing one or several closed bifurcation sets of the given system. The bifurcation sets for some model systems are found. It is demonstrated that the proposed mechanism of the translational motion induction can be realized, in particular, by applying an alternating elliptically polarized electric field to particles of nanometer dimensions occurring on a chemically inert crystal (e.g., graphite) surface. 相似文献
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电磁铸造过程中电磁压力与感应热计算 总被引:3,自引:1,他引:2
本文推惆了电磁铸过程中的磁感应强度表达式,并由此导出了电流强度与铸锭尺寸的关系式,计算的电磁压力与液体金属的静压头基本平衡。此外,推出了求解液柱内感应电流,焦耳热的关系式,计算的铸锭的温升与实测基本吻合。 相似文献