Evaluation and analysis of the radiation force in laser trap

Forces exerted on a small transparent dielectric sphere in a Gaussian beam is an-alyzed.The stable position of the sphere in the Gaussian beam was calculated.The effects ofthe sphere size,the beam radius etc.on the exerted forces,on the equilibrium positions aswell as on other parameters of the sphere are discussed.     

Investigation of nuclear reaction products by atomic force microscopy

The use of Atomic Force Microscope (AFM, from Corporate Head, Santa Clara, California, USA) opened a new way to study latent nuclear tracks. In our experiments we used plastic track detectors of the type CR-39 (Columbia Resin No. 39) Impinging ions with energy above a threshold of 180 keV can alter the molecular structure forming latent tracks. Since nuclear latent tracks have diameters in the range of 10 to 1000 nm, they can be visualized by AFM with a slight chemical etching (6 min in 6 n NaOH solution at 70 °C). These tracks are significant for the energy, momentum and the mass of the incoming particles. In our study, passive CR-39 detectors were irradiated by secondary particles produced bombarding ¹⁰³Rh by ¹⁶O and ¹²C in a wide range of energy (1 MeV/amu to 33 MeV/amu) at the MP Tandem generator of the Laboratorio Nazionale del Sud in Catania, Italy. The experiment was carried out in order to identify the secondary particles and to determine their density and the spatial distribution.     

Deuteron form factors and the tensor force

Results of a non-relativistic calculation of deuteron form factors are presented for separable potentials with and without tensor force. The tensor term in triplet state is added in such a way as to keep the values of deuteron binding energy,a _t andr _0t unaltered, so that the difference in the form factors can be regarded as the effect of tensor force only. The calculation has been performed for two different shapes of separable potentials and for three differentD-state probabilities to study their comparative effect.     

测试接地电阻实验的设计

利用模拟实验测试了形状规则和不规则接地体的接地电阻。     

Effect of three-body force on form factors

Conclusion The effect of increasing number of channels as well as the inclusion of the three-body force is very important in the charge form factor. We succeeded in getting a very good fit with the experimental result for³He. The experiment on³H is waited for. It will give important informations about the effect of the three-body force, as well as the neutron electro-magnetic form factor. A precise experiment about the first minimum of the magnetic form factor of³He is necessary.Presented at the symposium Mesons and light Nuclei, Bechyn, Czechoslovakia, May 27–June 1, 1985.     

Precise force measurement method by a Y-shaped cavity dual-frequency laser

A novel precise force measurement based on a Y-shaped cavity dual-frequency laser is proposed.The principle of force measurement with this method is analyzed,and the analytic relation expression between the input force and the change in the output beat frequency is derived.Experiments using a 632.8-nm Y-shaped cavity He-Ne dual-frequency laser are then performed;they demonstrate that the force measurement is proportional to a high degree over almost five decades of input signal range.The maximum scale factor is observed as 5.02×109 Hz/N,with beat frequency instability equivalent resolution of 10-5 N.By optimizing the optical and geometrical parameters of the laser sensor,a force measurement resolution of 10-6 N could be expected.     

一种视频图像规则圆目标的超分辨率位置测量方法

介绍了一种用于视频图像规则圆目标的超分辨率位置测量方法。分析了超分辨率测量的原理 ,并提出和完成了测量方案 ,取得了满意的结果。首先在目标静止时 ,连续采集多帧视频图像 ,通过叠加平均进行降噪 ;其次通过罗伯特微分算子进行边界探测 ,求出目标的大致位置 ;最后通过边界重心拟合法、边界圆拟合法和最小二乘法拟合求出目标的精确位置。理论分析和实验表明 ,完整圆目标时 ,测量精度可达 1/4像素 ;而当目标图像有缺陷时 ,边界圆拟合法和最小二乘法拟合测量误差增加较少 ,边界重心法的测量误差增加较多。在具体情况下 ,算法及参数应该作相应的调整     

Quantitative measurement of tip-sample forces by dynamic force spectroscopy in ambient conditions

We introduce a dynamic force spectroscopy technique enabling the quantitative measurement of conservative and dissipative tip-sample forces in ambient conditions. In difference to the commonly detected force-vs-distance curves dynamic force microscopy allows to measure the full range of tip-sample forces without hysteresis effects caused by a jump-to-contact. The approach is based on the specific behavior of a self-driven cantilever (frequency-modulation technique). Experimental applications on different samples (Fischer-sample, silicon wafer) are presented.     

New analysis procedure for fast and reliable size measurement of nanoparticles from atomic force microscopy images

Accurate size measurement during nanoparticle production is essential for the continuing innovation, quality and safety of nano-enabled products. Size measurement by analysing a number of separate particles individually has particular advantages over ensemble methods. In the latter case nanoparticles have to be well dispersed in a fluid and changes that may occur during analysis, such as agglomeration and degradation, will not be detected which could lead to misleading results. Atomic force microscopy (AFM) allows imaging of particles both in air and liquid, however, the strong interactions between the probe and the particle will cause the broadening of the lateral dimension in the final image. In this paper a new procedure to measure the size of spherical nanoparticles from AFM images via vertical height measurement is described. This procedure will quickly analyse hundred of particles simultaneously and reproduce the measurements obtained from electron microscopy (EM). Nanoparticles samples that were difficult, if not impossible, to analyse with EM were successfully measured using this method. The combination of this procedure with the use of a metrological AFM moves closer to true traceable measurements of nanoparticle dispersions.     

对“作用力与反作用力的关系”实验的创新

人教版教材在设计"作用力与反作用力的关系"实验时,忽视了用不同性质的力来定量验证牛顿第三定律,使得验证实验有失普适性.为此设计了通过发生相互作用的滑动摩擦力来定量验证牛顿第三定律的实验方案,并给出了实验的方法、技巧和结果.     

Adjacency effect estimation by ground spectra measurement and satellite optical sensor synchronous observation data

This paper addresses the estimation of adjacency effect of CBERS-2 image.The adjacency effect influences the digital number (DN) value of a pixel by adding surrounding scattering signals and path scattering signals.Based on the theory of radiation transfer model,a procedure is designed to measure the reflectance from the surface target materials and the materials in a box,which is 1.5 m above the surface to avoid upwelling reflectance.The results show that the adjacency effect varies from visible,near infrared and becomes steady within short infrared wavelength region;the adjacency effect weakens with the increase of distance between testing sites.The adjacency effect of CBERS-2 image is corrected and the quality of the resulting image is improved.     

光的力学效应及光阱力的测量

介绍一个利用光镊技术直观地演示光的力学效应的实验。简要讨论了开设这一实验的背景和目的，给出了光镊原理、实验装置、光阱力的测量方法和实验安排。     

Precise half-life measurement of the 26Si ground state

The β-decay half-life of ²⁶Si was measured with a relative precision of 1.4·10^?3. The measurement yields a value of 2.2283(27) s which is in good agreement with previous measurements but has a precision that is better by a factor of 4. In the same experiment, we have also measured the non-analogue branching ratios and could determine the super-allowed one with a precision of 3%. The experiment was done at the Accelerator Laboratory of the University of Jyväskylä where we used the IGISOL technique with the JYFLTRAP facility to separate pure samples of ²⁶Si.     

Explicit form of an implicit method for inverse force identification

Most existing time domain force identification methods are based on the state space method, which has the disadvantage of large discretization error with a low sampling frequency or a long sampling duration. This work transforms the conventional implicit Newmark-β algorithm into an explicit form for the solution of the Ax=b equations, which is an equivalent transformation, and it exhibits the same characteristics of Newmark-β algorithm as an implicit method. The accuracy of this method for the dynamic force identification is illustrated with two shear-frame buildings and a planar truss structure. Numerical results are compared with reference analytical responses. The new method gives more accurate identified force time histories compared with those from the conventional state space method for multiple sinusoidal and white noise excitations with 10% measurement noise in the responses.     

基于视频图像测量的母线折弯技术研究

现有折弯机在母线的角度测量中一般采用光栅尺或编码器,针对这种接触式检测方法存在的局限性,提出了基于视频技术的角度检测方法,这种非接触式测量方法不仅使角度的检测更加方便,而且增加了折弯机机头机械设计的灵活性.分析了母线在进行边缘检测时角度存在跳动的原因,提出了一种通过抑制伪边缘的方法来控制检测角度的不稳定性.以铜、铝母线...     

椭球粒子声辐射力计算及分析

针对水下椭球粒子,以声散射理论为基础,采用分波序列的方法,建立了椭球粒子声辐射力的理论计算模型。进而根据声辐射力计算公式,以刚性椭球粒子和液体椭球粒子为例,计算并分析不同Bessel波束作用下椭球粒子的轴向声辐射力函数特征。数值仿真计算结果表明,对于刚性椭球粒子,扁平椭球粒子相对于细长椭球粒子更有助于激发负声辐射力;对于液体椭球粒子,细长椭球粒子相对于扁平椭球粒子更加容易产生负声辐射力;对于不同介质的椭球粒子,不同的入射波束激发的负声辐射力的效果也存在明显的差异。该结果为复杂的尺寸和介质粒子声操控技术提供了理论的可行性。