基于网络环境的大学物理实验教学改革研究与实践

本文结合我校大学物理实验课程改革的具体实际, 介绍了课程教学的设计理念和课程教学的组织模 式, 通过课程改革的运行, 总结出大学物理实验课程改革对人才培养发挥的作用, 指出了课程改革存在的问题, 以 及解决问题的方法     

新课程视野下大学物理教学改革策略分析

基础课程改革的不断深入展开，使大学课程的受众群体在知识结构、学习能力和学习方式等方面都与以往有了较大差异。本文以大学物理课程为例，通过对基础课程改革主要理念的简单介绍，从教学理念、教学组织、教学方法和学习评价四方面阐述大学课程应该如何改革，做好与基础课程的教学衔接。     

"综合科学课程"的困难和对策--重读《科学课程论》

《基础教育课程改革纲要（试行）》中规定，在小学阶段，主要以开设综合课程为主；在初中阶段，综合课程与分科课程的开设并重．我国已经进入基础教育课程改革的第五个年头，但综合课程（特别是综合科学课程）在全国范围内的发展并不尽如人意，至今综合科学课程主要集中在少量国家级课程改革实验区实验（浙江省除外），     

贫困地区中学物理教学如何落实新课程理念

贫困地区和农村中学的课程改革面临诸多困境，而贫困地区的课程改革能否推进，直接影响着整个基础教育改革的推进．笔者处在贫困地区，对本地区十几所中学(包括市、县级重点中学和农村中学)进行了认真细致的调查研究，通过分析物理教学现状，提出了一些推进课程改革、落实新课程理念的设想，愿能抛砖引玉，从真正意义上推进新一轮课程改革．     

物理实验室课程资源的开发

实验是以实验室为基地的教学活动．2002年部颁的普通高中《物理课程标准》（以下简称：新课标）针对实验教学愈来愈凸现的重要性，指出：“实验是物理课程改革的重要环节，是落实物理课程目标、全面提高学生科学素养的重要途径，也是物理课程改革的重要资源．”把“实验”作为“物理课程改革的重要资源”的这一提法，在历次大纲中是前所未有的，给我们从事物理实验教学的教师提出了一个实验教学改革更深层次的要求，所以物理实验室课程资源的开发与利用是课程改革的重要部分．以下是笔者实施新课标以来在实验教学实践中利用开发物理实验室课程资源的一些做法．     

新课程理念下高师《中学物理教学论》课程的改革与实践

面对全球基础教育改革浪潮，2001年国家教育部颁布了《基础教育课程改革纲要（试行）》，调整和改革基础教育的课程体系、结构、内容，构建符合素质教育要求的新的课程体系．课程改革对中学教师的教育理念、教学行为、知识结构等方面都提出了严峻的挑战．因此，高师院校的《中学物理教学论》系列课程，应积极地调整培养目标、课程结构、课程内容，改革教学方法，培养适应时代发展要求、推进素质教育实施的新型的物理教师．     

立体化、创新型的光学课程教学体系与模式的研究

为了培养高水平的创新型人才,我们从精选课程教学内容、运用现代化的教学手段以及改革考核方式等方面对光学课程作了改革,取得了良好的教学效果.     

探讨物理实验教学融合S T EAM 理念的几种方法

把美国作为中国教育界的关注对象, 研究其教育科研成果, 促进中国的教育课程改革, 是我国基础教 育改革的途径之一. 当前美国课程改革中, S T EAM 教育是其基础教育改革的重点. 近些年的课程发展中, 提出了不 少可行性高、 课程资源完整的解决方案. 然而,这些解决方案仍然存在很多实践上的限制条件. 笔者通过研究美国 课程改革中运用的 S T EAM 教育理念,并通过在物理实验教学中,不断实践与总结,探讨并提出了几种融合 S T EAM 理念的方法     

利用多媒体技术完善《模拟电子技术》课程教学手段的改革

探讨了利用多媒体技术进行《模拟电子技术》课程教学手段改革的必要性 ,多媒体技术的发展为《模拟电子技术》课程教学手段改革带来的启示 ,科学有效地使用多媒体是教学手段改革的关键。多媒体技术在教学领域中使用存在的问题及其展望。     

浅谈物理专业太阳能发电方向的课程群设置和实施

课程群是为完善同一施教对象的认知结构和优化资源,而将本专业或跨专业培养方案中若干门在知识、方法、问题等方面有逻辑联系的课程加以整合而成的课程体系.本文浅谈了上海电力学院物理专业面向太阳能专业方向的课程群的设置以及改革的原因和必要性,以此课程群为依托,努力优化了教学内容,完善了实践和实习基地,建立了一整套创新能力拓展平台,尝试改革了课程群内课程的考核方式,取得了一定改革成效,提高了学生的创新能力,毕业生得到了用人单位的一致好评.     

A study on the best irradiation dose of X-ray for Hep-2 cells by Fourier transform infrared spectroscopy

Fourier transform infrared spectroscopy (FTIR) was employed to study the human epidermis larynx carcinoma cell lines (Hep-2) which were irradiated by different doses of X-ray.The results show that (1) the irradiation of X-ray damages the structure of the CH3 groups of the thymine in DNA,which restrains the reproduction of Hep-2 cells effectively,(2) the 8 Gy dose of X-ray irradiation changes the framework and the relative contents of some proteins,lipids and the nucleic acid molecules intercellular in the greatest degree,and (3) the 8 Gy dose of X-ray irradiation is the best irradiation dose for lowering the degree of the cancerization of Hep-2 cells according to the criteria for the degree of the cancerization reported recently.Meanwhile,the apoptosis of these cells were detected by using flow cytometry (FCM) primarily.It shows that the apoptotic ratio of the Hep-2 cells depends on the irradiation dose to some extent,but is not linearly.And the apoptotic ratio of the 12 Gy dose group is the maximum (20.36%),but the apoptotic ratios of the 2 to 8 Gy dose groups change little.     

Modification to first-order Born approximation for improved prediction of scattered sound from weakly scattering objects

When deriving the Fourier diffraction theorem based on the first-order Born approximation,the difference between wave number of the scattering object and that of the surrounding medium is ignored,causing substantial errors in sound scattering prediction.This paper modifies the Born approximation by taking into account the amplitude and phase changes between the scattering object and the water due to the wave number difference.By changing the radius and center position of the sampling circle in the Fourier domain,accuracy of the predicted sound scattering is improved.With the modified Born approximation,the computed far-field directional pattern of the scattered sound from a circular cylinder is in good agreement with the rigorous solution.Numerical calculations for several objects with different shapes are used to show applicability and effectiveness of the proposed method.     

Study on the radiation problem caused by electron beam loss in accelerator tubes

The beam dynamic code PARMELA was used to simulate the transportation process of accelerating electrons in S-band SW linacs with different energies of 2.5, 6 and 20 MeV. The results indicated that in the ideal condition, the percentage of electron beam loss was 50% in accelerator tubes. Also we calculated the spectrum, the location and angular distribution of the lost electrons. Calculation performed by Monte Carlo code MCNP demonstrated that the radiation distribution of lost electrons was nearly uniform along the tube axis, the angular distributions of the radiation dose rates of the three tubes were similar, and the highest leaking dose was at the angle of 160° with respect to the axis. The lower the energy of the accelerator, the higher the radiation relative leakage. For the 2.5 MeV accelerator, the maximum dose rate reached 5% of the main dose and the one on the head of the electron gun was 1%, both of which did not meet the eligible protection requirement for accelerators. We adopted different shielding designs for different accelerators. The simulated result showed that the shielded radiation leaking dose rates fulfilled the requirement.     

Fiber Modal Index Measurements Based on Fiber Gratings

A novel method based on fiber gratings for measuring the effective indices of fiber modes is proposed. The effective index difference between the core mode and a cladding mode was obtained by analyzing the interference fringe of a pair of cascaded long-period fiber gratings. In order to extract the core mode index from the measured index difference, an index matching oil immersion method is proposed. By analyzing the interaction between the cladding mode and the oil applied on the cladding surface, the mode order and the effective index of the involved cladding mode might be calculated. Experimental results about the interference fringe shifts induced by the oil index and the oil-applied length are also presented.     

Factors affecting the spectrum of an electromagnetic light wave on scattering from a semisoft boundary medium

The spectrum of an electromagnetic light wave on scattering from a semisoft boundary medium is discussed within the accuracy of the first-order Born approximation. It is shown that spectral shifts and spectral switches are affected both by the polarization of the incident light wave and by the characters of the scat-tering medium. Moreover, numerical results show that the direction at which the spectral switch occurs is governed by the characters of the scattering medium, whereas the magnitude of the spectral switch is affected by the polarization of the incident light wave.     

Temperature Sensitivity Control and Mechanical Stress Effect of Boron-Doped Long-Period Fiber Gratings

We will present in this work the quantitative analysis of the relationship between the doping concentrations of GeO 2 and B 2 O 3 in the core and cladding regions and the temperature sensitivity of the resonance wavelength shift in long-period fiber gratings (LPFGs). Based on this analysis, the temperature sensitivity was suppressed and enhanced to 0.002 nm/°C and 0.28 nm/°C, respectively. We will also discuss the effect of the residual mechanical stress on the optical and mechanical properties of LPFGs. In particular, we will present the measurement results of the dependence of the refractive index change and mechanical strength on the residual mechanical stress in the boron-doped fibers with depressed clad and matched clad.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Exploitation of the Fiber Capacity in Optical Networks Using Time, Frequency, and Space Division Multiple Accesses

In this work we investigate how to obtain very high capacity transmissions in optical networks taking into account the limitations due to the physical channel. We consider both the case in which all the users are connected by a star coupler and the case in which the users are directly connected by the network topology. As a reference, we consider a ring network and a Shuffle Multihop Network (SMN). The use of optical systems to implement high-capacity networks is numerically investi gated by means of numerical simulations taking into consideration the channel limitations due to the chromatic dispersion, the Kerr effect, and the amplified spontaneous emission (ASE) noise of the optical amplifiers. In our model, we consider that the signal, during the routing process that is performed at the user position, undergoes only an attenuation. We suppose the use of intensity modulated signals and receivers with direct detection. Packet switching and digital transmission are assumed with soliton and conventional nonreturn to zero signals. Both wave length and time division multiple accesses are considered. The results show that, in the case of the Time Division Multiple Access (TDMA) technique, the use of a star coupler to connect the users reduces the capacity of a network with respect to the case in which a direct connection of the users is used. This is due to the strong power fluctuations that are present during the signal propagation and to the large quantity of accumulated ASE noise. On the other hand, the use of a star coupler shows the advantage to being easily reconfigurable. The Wavelength Divison Multiple Access (WDMA) technique permits us to achieve higher capacities with respect to the TDMA. This is due to the fact that in the propagation conditions, due to the presence of a star coupler, high bit rate signals are strongly degraded. On the other hand, several low bit rate signals operating at different wavelengths can propagate with a low power level, avoiding strong degradation due to the Four Wave Mixing (FWM) effect. Among the topologies considered in this work, the SMN is the one that generally permits us to reach the highest throughput because in the SMN the signal hops in a limited number of Network Interface Units (NIUs) before reaching the final destination.     

Time domain finite volume method for the transient response and natural characteristics of structural-acoustic coupling in an enclosed cavity

A time domain finite volume method（TDFVM）based on wave theory is developed to analyze the transient response and natural characteristics of structural-acoustic coupling problems in an enclosed cavity.In the present method,the elastic dynamic equations and acoustic equation in heterogeneous medium are solved in solid domains and fluid domains respectively.The structural-acoustic coupling is implemented according to the continuity condition of the particle velocity along the normal direction and the normal traction equilibrium condition on the interface.Several numerical examples are presented to validate the effectiveness and accuracy of the present TDFVM.Then the effects of water depth on the acoustic and vibration characteristics and the natural characteristics of a structural-acoustic coupling system are analyzed.The numerical results show that the increase of water depth leads to a stronger coupling between the water and structure and the decrease of natural frequencies of coupling system,The computational cost and memory of this method are small and it can be applicable to structural-acoustic coupling problems in the heterogeneous fluid.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.