物理实验室建设及实验教学改革设想

在当前重视毕业生综合素质的背景下，学校把基础实验课放在了比较突出的位置，每年都向实验室投资，但由于原有的实验设施比较薄弱，实验室规模较小，加上近几年招生规模逐年扩大，学生人数剧增，物理实验室除了承担农机、交运、机电、机制、设计、自动、电气等理工专业的实验教学外，还承担了工商、工管等文科的实验教学任务，基本涵盖了全部在校本科生的物理实验教学，涉及面广。工作量大，如何进行实验室建设及实验教学改革成了当务之急，为此，本人提出以下设想．     

我心目中的于敏

人到老年，经常回忆起往事，岁月流逝，世事纷繁，绝大部分经历过的事情都已逐渐淡去，甚至烟消云散了，只留下一些对自己来说印象最深、影响最大的人和事，我从大学毕业以后，一直从事科研工作．工作单位虽然变化不多，却遇到了不少老师、同事和朋友，得到了他们的很多鼓励、指点和帮助，对此我都记忆犹新，往事历历在目，我一直从内心深处感谢他们。在他们当中，于敏同志是对我帮助最大、影响最深的人之一，是我的良师益友．大学毕业后，刚走向社会，我就认识了于敏同志，随后我们又长期为了一个共同目标，有了相当频繁的交往，一起讨论工作，这是我一生中有幸碰到的“机遇”之一。     

跨世纪工科大学物理教学体系的探讨

本文提出了一种新的工科大学物理教学体系，该体系具有知识面广，内容丰富，内容间的联系紧密等特点，并对近代物理的讲授提出了自己的看法，打破了经典和近代及高科技知识之间的严格界线，以时空观、能量、场、波为主线，把它们融为一体进行讲授，把人类最关心的问题，诸如能源危机、环境污染等编入教学内容之中     

脉冲中子探测系统的中子灵敏度能量响应

为了获得脉冲中子探测系统的中子灵敏度能量响应，编制了适合裂变中子测量探测系统灵敏度能响的一系列专用程序，研究了相应的实验标定技术，采用理论计算和实验验证相结合的方法，对几套探测系统中子灵敏度能量响应进行了研究，初步解决了标定需要的“单能、脉冲、高强度、多个不同能量的中子源”问题，使不确定度大大提高，满足了测量的要求。     

群众性课程改革实验是教育发展巨大推动力--纪念本刊中学物理教材改革实验20周年

20年前这个时候，本刊发表了题为《大家携手搞好中学物理教材改革研究》的文章，向全国物理学界、教育界宣告，为在我国促成“一个大纲、多种教材”的局面，《物理通报》决定以自己的实践，迈开探索中学物理教材改革的步伐．20年来的教改实践表明，我们当年的选择，适应了我国政治、经济、教育改革发展形势，体现了广大物理教育工作者的改革思想、热情和要求，为我国基础教育课程改革从理论研究和实践探索，为在我国实现“一个大纲、多种教材”起到了有力的推动作用．     

对物理新课程标准进行课外实验活动的实践与思考

新一轮中学物理课程改革已启动实施，从初、高中（人教版）新编物理教材看，无论是体系编排、栏目设置、教材内容等各方面都与旧教材有较大的变化．其一，在教材内容的引入中设计了许多贴近现代生活，语句充满诗情画意，启迪学生思维的有趣物理问题，创设了生动形象的物理情境．其二，根据教学内容的要求，旧教材中的许多演示实验变为大量的由浅入深的学生探究性实验，并增加了许多取材容易、制作简单的课外小实验，拓展了实验的空间，充分利用了中学生的好奇心和强烈的求知欲，     

无火焰原子吸收光度法连续测定化探样品中铜、铬、钴、镍、铅、镉

本文主要介绍了化探样品相态分析中无火焰原子吸收光度法测定化探样品中的铜、铬、钴、镍、铅、镉的分析方法。近年来，随着地质找矿工作的发展，地球化探人员对相态分析技术越来越感兴趣，在相态分析中，不同相态同一种元素的含量相差很大，给溶液的提取，制备及测定工作带来了很多不便，加之，大量的常量元素的存在尤其是钙、镁、锰、铁等元素极易产生干扰，在水溶态，离子态的分析液中铜、铬、钴、镍、铅、镉的含量又很低，给测试带来了很大难度，在相态的提取过程中，如果做平行、样品分析的话一个样品至少要制备八份溶液，工作量很大，因此，找到一个简单，快捷而又稳定可靠的测试方法是十分必要的，在测定中采用了磷酸为基体改进剂，它不仅可以消除基体的干扰，并可使各种元素测定的精密度得到很大改善。     

“3+3”新高考制度大中学物理教学衔接的研究与实践

本文针对“3+3”新高考制度下，大学物理与中学物理的衔接问题给出了解决方案。新高考制度下，大学与中学物理教学需要在知识体系和教学内容上有效衔接，同时，需要解决中学的应试教育向大学的科学思维过渡的问题，并提高学生在无监管下学习的主观能动性。哈尔滨工业大学物理学院大学物理教研室从课程体系、教学内容、教学方法、教学模式、选课机制、考试方式等方面进行了深入研究，给出了解决方案，并在教学过程中实施，取得了良好的教学效果。     

师专物理教育面向现代化的思考与实践

教育要面向现代化，面向世界，面向未来。为了贯彻和实践这一伟大教育思想，我系近年来组织教师到上海、苏州、无锡、张家港等教育发达地区考察学习，并参加了一些全国性物理教学改革的研讨会，受到很大启发和鼓舞，对教育现代化不仅有了直观的感受，而且提高了理性认识，有力地推进了我系教育现代化的进程。     

上海光源在生命科学中的应用

 生命科学包含涉及生命和生物有机体科学研究的许多分支，研究对象包含微生物、植物和动物，包括人类。经过几个世纪的发展，生命科学已经从单纯的描述逐渐发展成了一门理论、计算、实验等多领域交叉学科。自DNA双螺旋结构模型的提出以来，生命科学迈进了崭新的层次——分子生物学的层次，迄今为止，生命科学已经发展成了一门包含众多分支学科的科学体系。生命科学和生物技术，包括基因工程、合成生物学、基因组学和蛋白质组学，已经给人类健康带来了显著的改善。生命科学的发展有助于提高生活质量和标准，并在卫生、农业、医学、制药和食品科学领域得到广泛应用。蛋白质科学是生命科学的一个重要分支，在人类对于自身健康问题广泛关注的今天，蛋白质科学对于理解疾病的分子机制以及新药的开发都产生了强烈的影响，蛋白质科学也为生命科学和生物技术的发展提供了基础支持。     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Multi-pulse operation of a Kerr-lens mode-locked femtosecond laser

Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.     

Propagation of Helmholtz-Gauss beams in weak turbulent atmosphere

Based on the Rytov approximation of light propagation in weak turbulent atmosphere,the closed-form expressions of field and average irradiance of each one of the four fundamental families of Helmholtz-Gauss (HzG)beams:cosine-Gauss beams,stationary Mathieu-Gauss beams,stationary parabolic-Gauss beams,and Bessel-Gauss beams,which are propagating in weak turbulent atmosphere,are obtained.The results show that the field and average irradiance can be written as the product of four factors:complex amplitude depending on the z-coordinate only,a Ganssian beam.a factor of complex phase perturbation induced by atmospheric turbulence,and a complex scaled version of the transverse shape of the non-diffracting beam.The effect of weak atmospheric turbulence on irradiance distribution of the HzG beam can be ignored.     

An effective method for reducing speckle noise in digital holography

An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography.     

Influence of purity of HfO2 on reflectance of ultraviolet multilayer

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.     

Speech enhancement by array crosstalk resistant ANC and spectrum subtraction

Microphone array-based speech enhancement has great importance for speech communications and speech recognition. To reduce the aperture of the microphone array and to increase the effect of the speech enhancement will greatly broaden the application areas of the microphone array. An array crosstalk resistant adaptive noise cancellation method is therefore presented. And then an improved spectral subtraction algorithm is further cascaded to obtain better enhancement results. Theoretic analysis and experiments indicate that the proposed scheme needs only a very small microphone array while it simultaneously achieves a higher SNR improvement. Besides, the proposed scheme can be used in many noisy environments and is easy for real-time implementation.