物理解题中的“情景转换”

在物理解题中，经常会出现题述的情景比较陌生、复杂或模糊，从而导致解题思路不清或受阻中断的情形，这时最好不要钻牛角尖，应灵活运用所学知识，通过适当转换处理，把题述物理情景转换为熟知的、简单的、清晰的情景，再进行求解。     

浅析物理解题中的情景转换

在物理解题中，有些题目给出的物理情景比较模糊、复杂，导致解题思路不清，出现解题受阻或中断．如果灵活运用所学知识，通过巧妙的转换处理，将含糊不清的物理情景转换为我们熟悉的、简单的、清晰的物理情景，就会事半功倍，简化解题过程，达到破题目的．下面结合     

LiYF4:Nd3+中脉冲光泵浦的上转换蓝光

本文报道利用578.4nm的脉冲光泵浦,在室温和77K下,观察到LiYF4:Nd3+单晶中的上转换蓝光。由发光强度与泵浦光强度平方的直线关系,确定此上转换过程是双光子过程.通过对吸收谱和激发谱以及衰减曲线的研究,确定其上转换激发机制为两步激发和能量传递上转换。     

Quantum Optical Squeezing Transform for Generalizing Fractional Fourier Transform

By establishing the relation between the optical scaled fractional Fourier transform （FFT） and quantum mechanical squeezing-rotating operator transform, we employ the bipartite entangled state representation of two-mode squeezing operator to extend the scaled FFT to more general cases, such as scaled complex FFT and entangled scaled FFT. The additiyity and eigenmodes are presented in quantum version. The relation between the scaled FFT and squeezing-rotating Wigner operator is studied.     

Convolution Theorem of Fractional Fourier Transformation Derived by Representation Transformation in Quantum Mechancis

Based on our previous paper （Commun. Theor. Phys. 39 （2003） 417） we derive the convolution theorem of fractional Fourier transformation in the context of quantum mechanics, which seems a convenient and neat way. Generalization of this method to the complex fractional Fourier transformation case is also possible.     

基于AD650的模拟信号光纤传输系统的设计

在高电压、强磁场的强功率工况下,为了保护控制系统,须将测量系统和控制系统进行高低电位的隔离;采用电压频率(V/F)转换器AD650以频率形式通过数字光纤传输模拟信号,是高低电位隔离、远距离传输模拟信号而又不损失精度的最好解决方法;文中论述了其工作原理、系统组成,详细分析了硬件设计,并进行计算,确定其参数;实验结果表明,基于AD650芯片的传输系统,采用光纤传输,模拟信号传输精度小于0.1%,数据传输速率高,传输距离远,而且传输过程不受外界电磁场干扰,具有良好的线性度和分辨率;电路结构简单,对外界电容要求也简单,仅要求保持良好的稳定性,在实际工程应用中得到了优良的结果。     

伺服测试数据格式转换算法研究

测试数据及其格式转换是计算机测控领域的一项重要研究内容,对于伺服测试尤其如此。伺服型号繁多,不同型号测试数据差别很大,需要格式转换。某型号伺服测试软件数据格式转换效率较低,不能满足该型号快速判读以确定伺服产品状态的需求。对伺服测试软件生成的原始数据格式、待转换的物理量数据格式、数据格式转换逻辑进行了研究,提出了优化代码内存使用效率的方法,设计了新的转换算法,使转换效率有了质的提高。由于该方法具有普遍性,对类似问题具有借鉴意义。     

激光器型全光波长转换器的小信号分析

当外部光子注入到激光器有源腔中时 ,载流子把被注入光子消耗的一部分放大 ,进而激光器自身的输出功率将降低。基于此 ,可以实现全光波长转换。理论上基于载流子消耗机制 ,对激光器型波长转换器进行了小信号分析 ,给出了频率响应函数。理论分析表明 ,激光器型全光波长转换器的转换速度取决于激光器光子寿命以及激光器腔内的光子密度。     

980nm激发下Ho~(3+)/Yb~(3+)共掺杂ZrO_2-ZnO粉末的上转换发光特性

通过固相反应法制备了Ho3+/Yb3+共掺杂ZrO2-ZnO粉末样品,重点报道了Ho3+/Yb3+共掺杂ZrO2-ZnO粉末样品在980nm激发下的上转换发光现象。在常温下测试得到的发射光谱显示3个发射峰,中心波长依次为540,671和762nm,分别对应Ho3+的5S2/5F4→5I8,5F5→5I8,5S2/5F4→5I7或5I4→5I8跃迁过程。稀土离子的掺杂浓度明显影响样品的上转换发光特性,当Ho3+浓度确定的情况下,随着Yb3+含量增大,红光强度和绿光强度先减小后增大,近红外光却先增大后减小,而绿光强度与红光强度的比值一直减小。当Yb2O3含量为4.7mol%时,随着Ho3+含量增大,各波段荧光强度均减小,而绿光强度与红光强度的比值基本不变。双对数曲线显示3个波长的上转换发光的发射过程均为双光子过程,对样品的上转换发光机制做了详细的说明。XRD显示样品的均匀性良好。     

GaN基白光LED的研制与特性

本文报导了通过低压金属有机物化学气相沉积(MOCVD)的InGaN/GaN量子阱蓝光发光二极管(LED)与钇铝石榴石(YAG)荧光粉结合而得的白光发光二极管(W-LED).在室温、正向电流20mA时,W-LED轴向亮度为170mcd,显色指数(CRI)达到82,色温(CCT)为7448K,CIE色坐标是(0.296,0.316),接近纯白色(0.33,0.33).随着注入电流的增强,测量并探讨了白光LED的发射光谱与发光强度的变化.     

反应离子镀光学薄膜的微观结构分析

用反应离子镀方法制备了ＴｉＯ２单层膜及ＴｉＯ２／ＳｉＯ２多层膜，用透射电子显微镜分别观察了由反应离子镀方法及传统蒸镀法二种不同工艺制得的ＴｉＯ２单层膜及ＴｉＯ２／ＳｉＯ２多层膜的断面结构，并对ＴｉＯ２单层膜进行了喇曼分析和卢瑟福背散射分析。     

Specification of spectral line shape and multiplex dispersion by self-imaging and moiré technique

Due to finite width of a spectral line, the visibility of the moiré fringes formed by a grating and the self-image of another similar grating reduces by the increase of the self-image order. This effect is exploited to specify the spectral line shape by evaluating the Fourier transform of a function related to the visibility. Even, by using in-expensive optics, the technique can provide the spectral line shapes of rather broad widths—of the order of nanometer and more—by precisions that are comparable by those obtained by expensive Fourier transform spectrometers.Besides, it is shown that by comparing the line shapes obtained with and without a dispersive medium between the gratings, one can specify the dispersion function of the medium in the wavelength range covered by the spectrum.     

Chemical Analysis of Historic Art and Painting Conservation Materials (19th and 20th Centuries) from the National Museum in Krakow by Gas Chromatography–Mass Spectrometry and Fourier Transform Infrared Spectroscopy

Chemical composition of varnishes Vernis a Tableaux Vibert by Lefranc & Cie, Schutzfirnis für Oelgemalde Schmincke's Retuschier-Firnis by Schmincke & Co. Düsseldorf, Tempera-Firnis by Schmincke & Co. Düsseldorf, Bernstein-Gemaldefirniss für Ludwig'sche Petroleumfarben by Dr. Schoenfeld Düsseldorf, and Vernis Martin Pour Laquer by Lefranc & Cie Paris; oil medium Copal en pâte by Duroziez; essential oils Oleum Cupressi by Polak & Schwarz and Oleum Calami by Polak & Schwarz; fixative for charcoal, crayons, and pastels Nr 840/4 by Iskra & Karmański; and restoring medium for paintings Prof. Dr. Büttner's Phobus by Schmincke Düsseldorf were analyzed with gas chromatography–mass spectrometry. The analyses were conducted to obtain information about the exact composition of these products, which are stored at the National Museum in Krakow and were used by conservators. The results of research facilitate understanding of processes used in paintings and planning methods for their conservation.     

化学水浴法和磁控溅射法制备硫化镉薄膜的性能研究

以氯化铵、氯化镉、氢氧化钾和硫脲为反应物采用化学水浴法制备了硫化镉薄膜,为了作对比研究,采用射频磁控溅射以硫化镉为靶材,氩气为溅射气体,制备了硫化镉薄膜。采用X射线衍射、扫描电子显微镜和紫外-可见光光谱仪分别表征了硫化镉薄膜的结构、形貌和光学吸收特性。结果表明,采用以上两种方法制备的硫化镉均具有(002)择优取向,溅射法制备的硫化镉薄膜较致密,薄膜表面较光滑,平均晶粒尺寸在20～30nm;水浴法制备的硫化镉薄膜颗粒尺寸较小,缺陷较多。除了在短波段溅射所得硫化镉薄膜的透过率略差于水浴法所得硫化镉薄膜之外,溅射法制备的硫化镉薄膜的性能整体上优于水浴法制备的薄膜。两种方法制备的硫化镉薄膜的能隙在2.3～2.5eV。     

原子吸收光谱法测定中成药阿胶中铜、铬、镉、铅、砷、锑、锡和汞

本文以５０ｍｌ比色管作消化容器，硝酸－高氯酸混酸消化中成药阿胶，采用火焰原子吸收法测定其中的铜；石墨炉法测定其中的铬、镉、铅；氢化物法测定其中的砷、锑、锡。以硝酸－硫酸加过氧化氢水浴加热消化处理样品、采用冷原子法测定其中的汞，均取得较满意的结果。     

镧和铈对两种细菌生长的影响及胞内DNA的荧光光谱分析

为了研究镧,铈对细菌生长及核酸的影响,用光电比浊法测定了镧,铈和钙调蛋白抑制剂(氯丙嗪)存在时两种细菌的生长曲线,并用荧光光谱法研究了镧,铈对小牛胸腺DNA和细菌胞内DNA结构的影响。结果显示适当浓度(200 mg·L-1)稀土元素可以促进细菌的生长和繁殖,比对照提前进入对数期,扫描电镜观察也显示镧,铈可以促进枯草芽孢杆菌个体的生长,菌体体积比对照更大,但促进繁殖的作用会被氯丙嗪抑制,表明镧,铈促进细菌生长的机理可能与钙调蛋白的功能有关;荧光光谱分析显示镧,铈会使小牛胸腺DNA荧光增强,镧、铈浓度分别为5和10 mg·L-1时荧光增强作用最大;但镧使细菌胞内DNA荧光猝灭,铈使其荧光增强,结论认为镧,铈对核酸的影响远比想象的要复杂。     

The rigorous electromagnetic theory of the diffraction of vector beams by a circular aperture

The rigorous electromagnetic theory of the diffraction of vector beams by an aperture is proposed and numerically evaluated by the diffraction of vector Gaussian beams by a circular aperture. The results are compared with those, by using the vector Rayleigh–Sommerfeld diffraction integrals and angular-spectrum expression theory, showing a good consistency. The numerical calculation shows that the result calculated by the rigorous theory is much more precise than those calculated by the integral method in diffraction near field, and a highly consistency reaches by the three methods in diffraction far field. A further extension of the theory is discussed.     

碳化硅反射镜坯体光学加工的残余应力测量与分析

测量并分析了碳化硅反射镜坯体光学加工的残余应力。采用X射线衍射法测定了磨削成形、研磨以及抛光过程引入的表面残余应力的性质和大小;采用逐层抛光法测定了在用120#粒度金刚石砂轮磨削时引入的残余应力层厚度。研究结果表明:在用120#金刚石砂轮磨削加工时沿磨削方向和垂直于磨削方向分别引入了残余拉应力和残余压应力,其大小分别为40MPa和70MPa,应力层深度约为60μm,大于裂纹层深度;在用W7金刚石微粉研磨时引入了残余压应力,在其作用范围内残余应力平均值为60～80MPa;在抛光时理论上会引入残余压应力。在此基础上提出了在碳化硅反射镜坯体的光学加工过程中,可以通过研磨消除磨削引入的裂纹层和残余应力层。     

实时全息术检测透明物的一种新方法

介绍了实时全息术检测透明物的一种新方法,它采用物光再现的参考光和参考光通过全息图的直透光所形成的干涉图纹检测透明物体的变化。证明了这组干涉图纹与用参考光再现的物光和物光通过全息图的直透光所形成的干涉图纹分布规律相似,仅在相位上相差π。还讨论了这组干涉图纹的衬比和获得最佳衬比的条件。此方法可消除物光光路上某些因素带来的相位畸变,避开待测物体自发光的干扰,并可在全息图后方任意位置进行记录,这使实时全息术在实践中更具有灵活性,有助于它在更广阔领域内的应用。     

Chiral-Quantum-Optics-Based Supervised Learning

Based on the excellent control of single photons realized by atom-photon-chiral couplings,a novel quantum-optics scheme for supervised learning is proposed. The single-photon rotating and phase-shift operations, which can be controlled by another single photon, are realized by proper atom-photon-chiral couplings. Then, an algorithm to perform the supervised learning tasks, composed by integrating the realized gates, and implemented by the tunable gate parameters, is realized.