混沌，牛顿力学体系的再认识

混沌，牛顿力学体系的再认识邓家干，王兰芳（广西农业大学南宁）（陕西工学院汉中）本世纪前期，物理学家发现了相对论及量子力学。相对论消除了关于绝对空间与时间的幻想，使物理学对空间与时间的认识向前飞跃了一大步；量子力学则消除了关于可控测量过程牛顿式的梦，使...     

亚里士多德与物理学

物理学这门学科就是由亚里士多德创立的，研究了亚里士多德的物理学观点包括：（1）“四因说”；（2）“静止惯性和近距说”；（3）“自然界憎恶真空”学说；（4）地球球形说。     

望远镜的色差问题——小议牛顿在光学上为数不多的一次失误

我们知道，《光学》是牛顿的一本经典著作，该书副标题是“关于光的反射、折射、拐折和颜色的论文”，它集中反映了牛顿在光学研究方面的成就，其中最具代表的就是颜色理论。在光学发展的早期，人们对颜色的解释极为困难．在牛顿以前，欧洲人对颜色的认识流行着亚里士多德的观点，亚里士多德认为，颜色不是物体客观的性质，而是人们主观的感觉，一切颜色的形成都是光明与黑暗、白与黑按比例混合的结果。1663年玻义耳也曾研究了物体的颜色问题，他认为物体的颜色并不是属于物体的实质性的性质，     

关于亚里士多德落体运动结论的思考

1发现落体运动规律的传统描述谈到人类对落体运动的认识过程,不得不提到古希腊哲学家亚里士多德和意大利物理学家伽利略.从亚里士多德到伽利略再到牛顿,是人类对运动理性认识过程的几个里程碑.所有涉及落体运动的教科书上都写到,亚里士多德认为重的物体比轻的物体下落得快,而伽利略通过两种方式推翻了亚里士多德的结论.     

两电极静电同心球系统的近轴电子光学及其空间-时间像差

将从近轴解出发研究两电极静电同心球系统的空-时轨迹及其像差.由近轴轨迹方程和近轴运动方程出发,先求解两电极静电同心球系统中自光阴极逸出的运动电子的近轴空间-时间轨迹,然后讨论此系统的静动态电子光学及其空间-时间像差,揭示近轴光学系统成像的一般规律.文中定义和推导了各级近轴空间像差和近轴时间像差,得到了与关于近轴空间-时间像差同样的结论,表明完全可以直接由近轴轨迹方程和近轴运动方程出发来研究理想成像及其空间-时间像差.     

经典动力学与热力学的冲突

经典动力学与热力学的冲突韦文生（广西梧州师专贺州５４２８００）经典动力学与热力学关于时、空的根本观念和思维方法是冲突的。本文是作者对经典动力学与热力学的透视与比较，无意于挑起两种学说的论战，敬请同仁明鉴。１时间的可逆与时间之矢。时间的文化概念很不相同...     

阿奎那（Aquinas，Saint Thomas，约1225—1274）意大利神学家（Theologian，Italy）

阿奎那1240年进入那波利大学，以后在1244年加入多明我会（天主教派别之一），他的家庭对此竭力反对而将他软禁起来。他于1245年逃往巴黎，在阿尔伯特大师骷指导下学习。以后，他开始写关于亚里士多德^A17的评论并赢得极大声誉。他在意大利及法国各地教书，但他拒绝接受高的职位，包括那波利大主教职位。他成功建立了一种使亚里士多德哲学和天主教神学相协调的混合思想体系。     

激光雷达大气湍流测量方法研究

 报道了一种用激光雷达方法测量大气湍流的技术，利用发射激光束在空间所需位置产生一个聚焦光斑，通过此光斑处的大气分子瑞利散射机制形成一个空间的人造散射光源，接收系统对此光源的散射光进行探测，测量出从地面到此空间散射光源之间的大气湍流参数。给出了对武汉上空大气湍流测量的初步结果。得到了不同高度层的大气相干长度随时间的变化特性、平均值和起伏均方差，并对实验测量和模型计算的大气折射率结构常数在相应高度段的积分值进行了比较，二者积分值都在10-12量级，得到的结果基本相符。这种测量方法的实现，为测量空间不同方位、不同距离的大气湍流提供了一种新的手段。     

飞秒电子衍射系统的静态特性研究

超快电子衍射系统是认识超快物理、化学及生物过程的重要工具之一.介绍了自主研制的一套飞秒电子衍射系统，调试并测量了该系统的电子束斑特性、X-Y偏转板的偏转灵敏度等.在该系统上进行了金膜的静态电子衍射图像的测量. 关键词： 飞秒电子衍射 偏转灵敏度 时间分辨 空间分辨     

教学设计形成性评价与修改——物理教学设计系列讲座之五

教学设计方案是课堂教学过程设计中各要素分析和设计的终结性成果．对教学设计方案进行评价是教学设计的基本内容之一；教学设计的涵义本身就包括了对解决问题的预想方案进行评价的要求．通过评价，可以获取关于教学设计方案有效性、完整性、规范性、可实施性、创新性等方面的基本信息，     

Self-organization of five species in a cyclic competition game

Cyclic competition game models, particularly the “rock–paper–scissors” model, play important roles in exploring the problem of multi-species coexistence in spatially ecological systems. We propose an extended “rock–paper–scissors” game to model cyclic interactions among five species, and find that two of the five can coexistent when biodiversity disappears, which is different from the “rock–paper–scissors” game. As the number of fingers is five, we named the new model the “fingers” game, where the thumb, forefinger, middle finger, ring finger, and little finger cyclically dominate their subsequent species and are dominated by their former species. We investigate the “fingers” model in two ways: direct simulations and nonlinear partial differential equations. An important finding is that the number of species in a cyclic competition game has an influence on the emergence of biodiversity. To be specific, the “rock–paper–scissors” model is in favor of maintaining biodiversity in comparison with the “fingers” model when the variables (population size, reproduction rate, selection rate, and migration rate) are the same. It is also shown that the mobility and reproduction rate can promote or jeopardize biodiversity.     

Contrastive analysis on tone between Putonghua and Taiwan Mandarin

The differences of the pitch and duration of Chinese syllables between Putonghua （PTH） and Taiwan Mandarin （TM） were studied. The speech materials to be used are not only isolated syllables, but also sentences. The results reveal that： For the isolated syllables, T1 and T2 in TM are influenced by Minnan dialect, therefore their pitch are lower than those in PTH. T3 is fall-rise in PTH, while it is fall in TM. Moreover, the syllable duration sequence for different tone is T3〉T2〉T1〉T4 in PTH, while it is T1〉T2〉T3〉T4 in TM. For the syllables in sentences, T2 is mid-rise in PTH, while it is mid-level in TM. And the T3 is longer than T4 but shorter than T1 or T2 in PTH, while it is the shortest in TM. Furthermore the effects of prosodic phrase boundary on duration for different tones are almost the same in PTH, but the lengthening part of T1 or T2 is longer than that of T3 or T4 in TM.     

Experimental study on downstep in Chinese intonation

Downstep in pitch contour of Chinese Putonghua is examined using subtly designed sentences by controlling tone combinations. The results show both automatic and nonautomatic downstep phenomena exist in Chinese. In non-automatic downstep, low tones compress downwards the pitch range of the following syllables. and the main influence of downstep is on topline. Low tone not only lower the topline behind it, but also raise the high tones before it, the effects are compatible with each other. In automatic downstep, the topline of pitch contour in intonational phrase is presented as a linear downtrend, but it differs among speakers due to the effect of personal stress practice. In comparison with downstep phenomenon in other tone or non-tone languages, the downstep ratio in Chinese is not constant, and the domain of downstep is not limited within the adjacent tones.     

Abelian-Higgs phase of SU(2) QCD and glueball energy

It is shown that SU(2) QCD admits an dual Abelian-Higgs phase, with a Higgs vacuum of a type-Ⅱ superconductor. This is done by using a connection decomposition for the gluon field and the random-direction approximation. Using a bag picture with soft wall, we presented a calculational procedure for the glueball energy based on the recent proof for wall-vortices [Nucl. Phys. B 741(2006)1].     

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.     

Signal generation in an isotropic medium in scanning electron acoustic microscope

Based on the research in Ref. [5][Materials Science and Engineering, 1989; A122： 57 63], an improved model of heat source is set up, the different modes of Lamb wave in an isotropic sample generated by a chopped electron beam at frequency f are obtained with integral transform and normal function expansion method, and the output signal of PZT coupled at the back surface of the sample is found out. The generation mechanism of SEAM （Scanning Electron Acoustic Microscopy） signal is discussed. It shows that the SEAM is a near field imaging technique with high spatial resolution and its best lateral spatial resolution is about 2√2α （α is the radius of the focused electron beam）. Some of experimental results of SEAM images are presented in the paper and it shows that the spatial resolution of SEAM is better than 0.5 μm and smaller than the thermal diffusion length of the sample. Therefore the character of near field imaging in SEAM is also proved experimentally.     

High efficiency filtering using two-dimensional photonic crystal coupled cavity structures

Transmission spectra of coupled cavity structures (CCSs) in two-dimensional (2D) photonic crystals (PCs) are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain (FDTD) method, and the results show that within a very short coupling distance of about 3λ, where λ is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies.