“油膜法”实验用粉剂的特性及粉剂的选择

提出了"油膜法"测分子直径实验用粉剂应具有的特性、衡量粉剂特性的指标及检测方法,为正确选择粉剂提供依据.     

2009年全国高考理综（重庆卷、四川卷）物理试题评析

1 总体评价 今年重庆、四川两地的高考理综物理试题,遵循教育部颁布的<普通高等学校招生全国统一考试分省命题工作暂行管理办法>,坚持了"有助于高等学校选拔人才、有助于中等学校实施素质教育和有助于扩大高校办学自主权"的原则,体现了"着眼于正确导向,立足于平稳推进,确保试题宽严适度"的指导思想.     

天上力与地上力的统一(Ⅰ)

人类对力的认识经历了漫长的历史过程。力的概念,起先可能是从原始人类在狩猎活动中需要用力投掷石块等以击倒野兽的体验中得来的。公元前4世纪,我国思想家墨翟就对"力"做出了正确的表述,他在《墨     

"船渡河模型"的负迁移

在高考试题中实际问题的题目占有很大的比例,侧重于考查学生的实践能力.要正确分析和解决实际问题,必须弄清实际问题的物理过程,建立正确的物理图景,建构出正确的物理模型.但有时在没有弄清实际问题的物理过程的情形下,就可能造成物理模型的负迁移,得出错误的结论.以下就切割玻璃的实际问题所引起的"船渡河模型"的负迁移,谈一下我们粗浅的看法.     

作者联系人不得是“挂名”的,其地址不得省略

作者联系人及其地址不得是"挂名"的、"摆设"的,因为这不仅有作假之嫌,而且容易造成邮件无人认领和邮件丢失。联系人地址必须正确、真实、详细地写在论文中相应位置,写在论文外无效。某作者联系人只告诉了编辑部他单位所在的城市,未告知街道名称和门牌号数。确实,他单位是该城市     

作者联系人不得是“挂名”的,其地址不得省略

作者联系人及其地址不得是"挂名"的、"摆设"的,因为这不仅有作假之嫌,而且容易造成邮件无人认领和邮件丢失。联系人地址必须正确、真实、详细地写在论文中相应位置,写在论文外无效。某作者联系人只告诉了编辑部他单位所在的城市,未告知街道名称和门牌号数。确实,他单位是该城市     

作者联系人不得是“挂名”的,其地址不得省略

作者联系人及其地址不得是"挂名"的、"摆设"的.因为这不仅有作假之嫌,而且容易造成邮件无人认领和邮件丢失。联系人地址必须正确、真实、详细地写在论文中相应位置,写在论文外无效。某作者联系人只告诉了编辑部他单位所在的城市,未告知街道名称和门牌号数。确实,他单位是该城市     

物理实验课程中"课程思政"融合式教学模式建设与探索

"课程思政"的提出与实施,不仅符合新时代高校思想政治工作需求,亦是"三全育人"理念的有效举措之一。以物理实验课程为例,阐述了物理实验课程中引入"课程思政"的必要性,同时从"思政显性育人"和"思政隐性育人"两个方面分析总结了 "课程思政"在物理实验课程中的切入点与落脚点。在充分发挥实验课程育人功能的同时提高学生的科学素养与爱国情怀,树立正确的人生观与价值观。目前的初步探索以期为相关通识实践类课程的思政建设与改革提供参考。     

作者联系人(通讯作者)不得是“挂名”的,其地址不得省略

作者联系人(即通讯作者)及其地址不得是"挂名"的、"摆设"的,因为这不仅有作假之嫌,而且容易造成邮件无人认领和邮件丢失。联系人地址必须正确、真实、详细地写在论文中相应位置,写在论文外无效。     

电学典型题错解剖析

1 物理概念理解不清 [例1](2008年山东潍坊)将标有"220 V,15 W"的甲灯和"220 V,60 W"的乙灯串联后接在220 V的电源上,组成闭合回路(设灯丝电阻不变)则下列判断正确的是     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Research on beamforming method for dual-line array with space mismatch between the two line arrays

The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Retrieval of ultraviolet skylight radiances and O3 slant column densities from balloon-borne limb spectrometer

With a novel light-weight and absolutely calibrated ultraviolet （UV） spectrometer, UV skylight radiances and O3 slant column densities are measured by balloon-borne limb measurements in Xinjiang area, China. UV skylight radiances measured at the height of 31 km are compared with the results from Modtran in the wavelength range from 290 to 420 nm. O3 slant column densities are derived from radiance spectra in the Huggins bands （320 - 335 nm） using differential optical absorption spectroscopy method. And the parameter exhibits a good correlation with the same value simulated by radiative transfer model （Tracy）. The O3 profile simultaneously measured by an O3 sonde is used as input in Tracy calculations. The O3 sonde is launched on the same balloon.     

Design optimization of highly sensitive LSPR enhanced surface plasmon resonance biosensors with nanoholes

For breaking through the sensitivity limitation of conventional surface plasmon resonance (SPR) biosensors, novel highly sensitive SPR biosensors with Au nanoparticles and nanogratings enhancement have been proposed recently.But in practice, these structures have obvious disadvantages.In this study, a nanohole based sensitivity enhancement SPR biosensor is proposed and the influence of different structural parameters on the performance is investigated by using rigorous coupled wave analysis (RCWA).Electromagnetic field distributions around the nanohole are also given out to directly explain the performance difference for various structural parameters.The results indicate that significant sensitivity increase is associated with localized surface plasmons (LSPs) excitation mediated by nanoholes.Except to outcome the weakness of other LSP based biosensors, larger resonance angle shift, reflectance amplitude, and sharper SPR curves' width are obtained simultaneously under optimized structural parameters.     

Polymer gratings based on photopolymerization for low-order distributed feedback polymer lasers

Novel polymer distributed feedback(DFB)gratings are fabricated based on photopolymerization to reduce lasing threshold of polymer lasers.A photopolymer formulation sensitive to 355-nm ultraviolet(UV)light is proposed for the fabrication of polymer gratings and it can be used to form polymer films by spin-coating process.A very low surface-relief depth ranging from 12.5 to about 1.0 nm has been demonstrated with a refractive-index modulation of about 0.012.The experimental results indicate that such polymer gratings have promising potentials for the fabrication of low-order DFB organic semiconductor lasers.