An optimal scheme for top quark mass measurement near the t threshold at future e~+e~- colliders

A top quark mass measurement scheme near the t production threshold in future e~+e~- colliders, e.g. the Circular Electron Positron Collider(CEPC), is simulated. A χ~2 fitting method is adopted to determine the number of energy points to be taken and their locations. Our results show that the optimal energy point is located near the largest slope of the cross section v. beam energy plot, and the most efficient scheme is to concentrate all luminosity on this single energy point in the case of one-parameter top mass fitting. This suggests that the so-called data-driven method could be the best choice for future real experimental measurements. Conveniently, the top mass statistical uncertainty can also be calculated directly by the error matrix even without any sampling and fitting. The agreement of the above two optimization methods has been checked. Our conclusion is that by taking 50 fb~(-1) total effective integrated luminosity data, the statistical uncertainty of the top potential subtracted mass can be suppressed to about 7 Me V and the total uncertainty is about 30 Me V. This precision will help to identify the stability of the electroweak vacuum at the Planck scale.     

非线性物理破解神经编码机制

信息在神经系统中以脉冲点序列的形式传输和处理，神经系统如何通过脉冲点序列对所表达的信息进行编码，一直是一个谜．人们曾普遍认为，神经可能通过发放率（单位时间发放脉冲出现的次数）对信息编码，也有人猜测，神经可通过脉冲点序列的时序编码．由于神经发放的随机性，这就使得任何编码机制都面临着被表达信息的确定性与表达该信息的信号的随机性的矛盾．通过神经非线性随机动力学模型，文章作者发现，神经点序列的发放率对点序列的时序信息传输的影响，揭示了神经点序列时序信息在神经非线性传输中的随机共振特征．由此预期，并进一步通过听觉心理物理实验观察到，在一定条件下噪声对听觉的增强作用．从而通过非线性物理揭示了听觉时序编码机制的存在以及在时序编码中随机性噪声的积极作用．     

信息技术与高三物理实验教学整合效果实践研究

基于以班为单位的信息技术与高三物理实验教学整合的实践研究,运用SPSS.11统计软件对数据进行统计分析,论证了该教学模式的价值,总结了实践研究的效果,对研究成果进行了反思.     

用近红外光拓扑图技术短期预测脑梗塞

本研究用近红外光大脑拓扑图技术(near-infrared cerebral topography, NIRS topography),对大鼠大脑中动脉线栓梗塞模型的皮层缺血部位进行定位成象.我们利用氧合血红蛋白和去氧血红蛋白对近红外光的吸收峰值波长分别为850nm和760nm的原理,制作了NIRS拓扑仪.分别用NIRS拓扑仪、磁共振成象和解剖样本染色对10只SD雄性大鼠大脑皮层缺血部位进行成象.结果表明,NIRS拓扑图所显示的皮层缺血面积与磁共振图象及解剖样本所显示的皮层缺血面积的相关系数分别为0.82(p<0.05)和0.89(p<0.01).     

信息技术与高中物理实验教学整合效果实践研究——以整合“高二物理实验”为例

基于以班为单位的信息技术与高二物理实验教学整合实践研究,运用SPSS19统计软件对数据进行统计分析,论证了该教学模式的价值,总结了实践研究的效果,对研究成果进行了反思.     

Novel modal interferometer based on ring-core photonic crystal fiber

An original design of ring-core photonic crystal fiber （RPCF） is proposed. By splicing a section of the homemade RPCF between two segments of single mode fibers （SMFs）, a simple modal interferometer is presented and experimentally demonstrated. Owing to the effects of the collapsed region, the ring modes in RPCF can be effectively activated. To our knowledge, it is the first time to demonstrate the modal interferometer based on the interference between the ring modes, which is different from the previously reported interferometers based on the interference between core modes or cladding modes. The temperature and strain characteristics of the interferometers with different lengths of RPCF are investigated.     

三维电极电助光催化降解直接湖蓝水溶液的研究

 以500W高压汞灯为光源,在TiO2光催化剂和电催化剂同时存在下,联合多相三维电极技术与光催化技术,对直接湖蓝5B水溶液进行了电助光催化降解的研究．实验结果表明,浓度为0．5mmol／L的直接湖蓝5B水溶液经30min的光电催化降解,其大环结构可迅速破坏,颜色可迅速褪去,色度去除率高达96．8％,COD去除率可达66．7％．考察了空气流速、光催化剂加入量、底物的初始浓度、电解槽电压、pH值、电导率、以及曝气量等因素对直接湖蓝5B脱色率及COD去除率的影响．     

A novel method of rapidly modeling optical properties of actual photonic crystal fibres

<正>The flexible structure of photonic crystal fibre not only offers novel optical properties but also brings some difficulties in keeping the fibre structure in the fabrication process which inevitably cause the optical properties of the resulting fibre to deviate from the designed properties.Therefore,a method of evaluating the optical properties of the actual fibre is necessary for the purpose of application.Up to now,the methods employed to measure the properties of the actual photonic crystal fibre often require long fibre samples or complex expensive equipments.To our knowledge, there are few studies of modeling an actual photonic crystal fibre and evaluating its properties rapidly.In this paper,a novel method,based on the combination model of digital image processing and the finite element method,is proposed to rapidly model the optical properties of the actual photonic crystal fibre.Two kinds of photonic crystal fibres made by Crystal Fiber A/S are modeled.It is confirmed from numerical results that the proposed method is simple,rapid and accurate for evaluating the optical properties of the actual photonic crystal fibre without requiring complex equipment.     

一种覆盖全通信波段的新型宽带偏振无关双芯光纤定向耦合器的研究

提出了一种新型的双芯光子晶体光纤, 应用全矢量有限元方法分析了光纤各种结构参数对光纤宽带特性和偏振无关特性的影响. 在此基础上优化设计了一种50:50的双芯光子晶体光纤耦合器, 在1.225—1.675 μm波长范围内实现分光比小于1%、两偏振态之间的分光比差小于0.5%的优良特性. 由于引入了仅对偏振特性影响明显的相对独立的中心调制区, 不仅降低了光纤的优化设计难度, 而且实现了与普通单模光纤相匹配的模场特性, 能有效地降低耦合器的接续损耗与制作难度. 研究成果为研制接续损耗低、超宽工作带宽、偏振不敏感等特性的新型光定向耦合器提供了理论基础.     

光电元件光谱特性实验的微机控制

利用微机，集数据采集、存贮、处理、结果显示为一体，完成光电元件光谱特性的测试，并可进行曲线和数据的打印。