非接触光电窥测仪瞄准及定位方法研究

在非接触光电窥测仪的设计中需要解决两个基本问题：一是如何通过特殊的光学手段把在内孔狭小空间中的被测信息提取出来;二是如何进行测头定位来解决测量基准问题。本文报导了我们设计的非接触光电窥测装置的工作原理。通过方案比较,提出了以图像位置偏移作为瞄准判据及５ 步定位方法,分析了它们的精度及灵敏度     

为了遥远的祭奠——漫话海森伯

最初,我深为惊恐.我感到,通过原子现象的表面,我正在窥测着一个奇妙的内部,而对自然界如此慷慨地展现在我面前的丰富的数字结构,使我感到眼花缭乱.     

L—B技术及其近期应用

本文简要回顾了自1962年H.Kuhn首次在L-B膜中引入有光活性功能的分子以来,L-B技术的进展。介绍了L-B膜的制备及其结构和性能,并由目前L-B技术的现状窥测了它在物理上的应用前景。     

天行见物理之十一 武库渊深

<正>初陶唐出自伊祁,圣人之后,世食旧德。降及武库,应乎虬精。恭闻渊深,罕得窥测,勇功是立,智名克彰。缮甲江陵,祲清东吴,建侯于荆,邦于南土。河水活活,造舟为梁。洪涛莽汜,未始腾毒,《春秋》主解,膏隶躬亲。呜呼笔迹,流宕何人?——杜甫《祭远祖当阳君文》     

漫谈物理学的过去、现在与未来

文章试图对物理学的发展历史作一透视，从而理解其现状，并进而窥测其未来的前景，我们希望这一看法对于当今从事物理学教学与科研的人士有所助益，由于物理世界的层次化，诸层次之间既可能存在耦合，又可能出现脱耦，因而大量粒子所构成的复杂体系中所涌现的各种层展性质就不能简单地还原成个别粒子所服从的规律，我们根据这一观点并结合物理学的未来前景，讨论了当今物理学研究的若干前沿问题，一切迹象预示着物理学将有光明的前景     

GFAAS中理论原子化效率与原子化温度的关系的研究

本文在有效地控制和消除基体干扰的基础上 ,探讨了Ag ,As,Au ,Bi,Cd ,Co ,Cr,Cu ,Fe ,Ga,Hg ,Mn ,Mo ,Ni,Sb ,Pb和V元素的理论原子化效率与原子化温度的关系。研究表明 :元素的理论原子化效率是原子化温度的函数 ,在一定的原子化温度范围内 ,理论原子化效率与原子化温度呈线性递增关系 ,对研究的十八个元素其线性的相关系数在 0 994 0～ 0 9993之间 ,且斜率大部分在 0 0 6～ 0 0 7之间 ,说明在一定的原子化温度范围内 ,理论原子化效率随原子化温度变化的斜率是相近的。     

ICP-AES法测定广西中药白花丹不同部位常量及微量元素

采用电感耦合等离子体发射光谱法(ICP-AES) 分析广西中药白花丹根、茎、叶3个部位的20种常量及微量元素。结果显示,白花丹中除了含人体必需的常量元素K,Ca,Na,Mg外, 还有Zn,Fe,Mn, Cr,Co等必需的微量元素和其他元素Mo, Sb,Bi,Cd, Sr,Pb,Cd,As等。各元素的含量在白花丹的根,茎,叶中分布不同, 在叶和根中的含量比较丰富,与白花丹的抗菌, 抗肿瘤及抗氧化活性的药用有效部位在根部和叶部的结果一致,如Na,K,Ca,Zn,Fe,Mn,Sr,Cu,Co等含量在叶中含量最高,根次之。在许多抗癌中药中,Zn,Mn,Fe的含量通常比较高,Cr,Sr,Cu的含量也至关重要,作为传统抗癌中药的白花丹中就含有丰富的Zn,Mn,Fe和一定量的Sr,Cr,Cu元素,测定结果为探讨中草药中常量、微量元素与生物活性之间的相互协同关系提供了有用的数据,也为更好地开发和利用白花丹药用资源提供理论依据。     

稀土纳米金对银染效果的影响及其UV-Vis吸收光谱

制备了La,Ce,Nd,Sm,Eu,Gd,Dy微粒和纳米金,分别用La,Ce,Nd,Sm,Eu,Gd,Dy微粒替代部分的纳米金,研究了La-Au,Ce-Au,Nd-Au,Sm-Au,Eu-Au,Gd-Au,Dy-Au微粒分别对银染效果的影响及其紫外可见(UV-Vis)吸收光谱。与纳米金相比,La-Au,Ce-Au,Nd-Au,Sm-Au,Eu-Au,Gd-Au,Dy-Au微粒可延长银染后的斑点持续的时间,其中Nd-Au微粒的效果最好,斑点持续的时间为30 min,是纳米金的2.7倍;可大幅度加深斑点的颜色,其中Nd-Au,Sm-Au微粒的效果最好,用Nd微粒替代部分的纳米金,纳米金用量降低了80%,但还能提高银染法的灵敏度。在200～800 nm范围,La,Ce,Nd,Sm,Eu,Gd,Dy微粒和纳米金溶液的UV-Vis吸收光谱只有一个吸收峰,λ_max分别为275,277,276,276,278,277,278和521 nm;La-Au,Ce-Au,Nd-Au,Sm-Au,Eu-Au,Gd-Au,Dy-Au微粒混合液的UV-Vis吸收光谱有两个吸收峰,λ_max(RE)和λ_max(Au)分别为276和522 nm,276和522 nm,276和523 nm,276和523 nm,276和522 nm,276和522 nm,276和523 nm,纳米金和La微粒的吸收峰的波长发生了红移,Ce,Eu,Gd,Dy微粒的吸收峰的波长发生了蓝移,Nd,Sm微粒的吸收峰的波长不变,纳米金与稀土微粒可能有相互作用。     

磁化溶液样品对ICP发射光谱的增敏效应

利用磁感应强度为0.24T的磁场处理含乙醇的水溶液,研究了样品溶液的物理性质和雾化特性以及样品溶液中元素的谱线强度随磁化时间的变化情况,并且讨论了磁化机理。实验结果表明,随着磁处理时间的延长,分析样品的有效利用率提高了;当样品中加入乙醇时,元素的谱线强度较早地出现了峰值。在磁化时间为2 h的条件下,不含乙醇的样品溶液中,元素Zn, Pb, Cd, Fe, Si, Cu, Cr和Sr的谱线强度比溶液未磁化时分别提高了22.9%, 38.8%, 25.6%, 48.3%, 52.4%, 6.0%, 22.3%和22.7%;含6%乙醇的样品溶液中,元素Zn, Pb, Cd, Fe, Si, Cu, Cr和Sr的谱线强度比溶液未磁化时分别增加了22.4%, 42.6%, 39.4%, 43.9%, 72.4%, 9.7%, 16.1%和17.1%。样品溶液磁化后进行分析, 有利于降低光谱分析检出限。     

声学消息

恰好四十年前,Zwikker,Kosten的经典著作“Sound Absorbing Materials”出版(有中译本,席维克、柯斯汀《吸声材料》,科学出版社)奠定吸声材料的理论基础,Mechel的专著“Schallabsorber”是一个重大发展。书分三卷,卷一,外声场,即声场与吸声体的相互作用;卷二,内声场,即吸声体的构造,应用;卷三,计算程序,是辅助材料,现在出版的是卷一。本卷有十四章,1.引言,2.文献,3.声场基础;4.声场与吸声体相互作用,5.吸声带的吸收,6.柱形吸声体,7.吸收球,8.无穷平面吸声体,9.辐射阻抗,10.声场激发的表面辐射阻抗,11.表面波,     

A Review of Security Evaluation of Practical Quantum Key Distribution System

Although the unconditional security of quantum key distribution (QKD) has been widely studied, the imperfections of the practical devices leave potential loopholes for Eve to spy the final key. Thus, how to evaluate the security of QKD with realistic devices is always an interesting and opening question. In this paper, we briefly review the development of quantum hacking and security evaluation technology for a practical decoy state BB84 QKD system. The security requirement and parameters in each module (source, encoder, decoder and detector) are discussed, and the relationship between quantum hacking and security parameter are also shown.     

Enhancement of image quality by using metamaterial inspired energy harvester

Metamaterial energy harvester based subwavelength imaging structure is presented. Besides, 2×2 array patch antenna is designed to create incident radiated signal towards the proposed harvester structure. Harvested energy is converted to DC voltage signal by using Schottky diodes and each cell is represented by 256 grey levelled pixel value. Therefore, any incident electromagnetic wave placed in the operating frequency range can be monitorized. In the experimental study, experiments are realized with and without antenna to investigate the effects of instantaneous electromagnetic waves and the observed images. Afterwards, another experiment is conducted to observe the effects of metal plate which is located between the antenna and the harvester structure. The last experiment is performed by using a Yagi Uda antenna for sub-wavelength imaging. The proposed harvester structure can be used in various applications such as energy harvesting, incident wave tracing, crack detection, spy device detection, medical imaging, and so on.     

Recent Trends in Low-Temperature Nuclear Orientation and Nuclear Magnetic Resonance on Oriented Nuclei

Recent trends in Low-Temperature Nuclear Orientation (LTNO) and its site-selective derivative, Nuclear Magnetic Resonance on Oriented Nuclei (NMRON), are reviewed. Traditional areas of endeavour using elemental ferromagnetic hosts remain strong with significant improvements in methodology since last reviewed [1]; but there are new emphases emerging in solid-state physics and especially magnetism. Exotic single crystals hosts and MBE-grown multi-layers are gaining increased prominence as the principal focus of LTNO study. Increasingly, in off-line work and very recent on-line implantation into insulators [2], the radioactive probes are often chosen to be isoelectronic with an abundant chemical species within the host, rather than representing an extremely dilute, electronic impurity spy. Recent NMRON on a heavy rare earth, isoelectronic probe in an ordered rare earth halide opens up new dimensions. This revised version was published online in September 2006 with corrections to the Cover Date.     

Security analysis on some experimental quantum key distribution systems with imperfect optical and electrical devices

In general, quantum key distribution （QKD） has been proved unconditionally secure for perfect devices due to quantum uncertainty principle, quantum noneloning theorem and quantum nondividing principle which means that a quantum cannot be divided further. However, the practical optical and electrical devices used in the system are imperfect, which can be exploited by the eavesdropper to partially or totally spy the secret key between the legitimate parties. In this article, we first briefly review the recent work on quantum hacking on some experimental QKD systems with respect to imperfect devices carried out internationally, then we will present our recent hacking works in details, including passive faraday mirror attack, partially random phase attack, wavelength-selected photon-number-splitting attack, frequency shift attack, and single-photon-detector attack. Those quantum attack reminds people to improve the security existed in practical QKD systems due to imperfect devices by simply adding countermeasure or adopting a totally different protocol such as measurement-device independent protocol to avoid quantum hacking on the imperfection of measurement devices [Lo, et al., Phys. Rev. Lett., 2012, 108： 130503].     

基于区域合并的动态阈值分割算法

在传统分块分割再合并阈值法的基础上,引入图像区域合并的思想,以邻近区域阈值相似性作为判断区域合并的依据,借助人机交互式系统,运用待识别目标灰度与完成区域合并的阈值作加权,消除区域灰度不连续,实现目标与背景的有效分离,减少算法的运算量,提高目标识别精度.实验证明,该算法实现简单且行之有效.     

L波段端面发射高效率磁绝缘线振荡器

 建立了磁绝缘线振荡器自磁绝缘的理论模型,给出了磁绝缘电流计算公式。然后给出了非线性稳态的最大轮辐电流计算公式,并据此分析了负载限制型磁绝缘线振荡器的最大效率。提出一种新型的端面发射型磁绝缘线振荡器,在二极管电压590 kV,二极管电流为55.47 kA情况下,粒子模拟得到周期平均功率6.1 GW左右,工作主频为1.24 GHz,束波转换效率18.64%左右。端面发射型磁绝缘线振荡器的效率比负载限制型磁绝缘线振荡器的最大效率提高6%左右。端面发射的电流不参与束波互作用,由于端面发射的电流比较小,在总电流不变的情况下参与束波互作用的电流增多,从而提高了效率。最后分析了角向磁场的分布以及自磁绝缘的情况。     

基于半像素错位的多幅图像重建高分辨率图像技术研究

介绍了一种基于半像素错位的多幅图像重建高分辨率图像技术。分析了半像素错位的多幅图像与高分辨率图像各像素灰度值的对应关系 ,并从CCD数字化采样的角度进行了论证。同时 ,结合实际摄像机CCD结构 ,求出了高分辨率图像重建的计算公式 ,并通过实验进行了验证和完善。重建的本质是以原高分辨率图像的 4邻域平均图像为基础 ,增加一定比例的边缘细节信息 ,去接近原高分辨率图像。CCD的动态范围越大 ,图像的灰度级越多 ,那么计算误差就越小 ,图像的边缘细节信息就可以利用更多 ,重建的图像就越接近原高分辨率图像。通过实验和分析表明 ,利用半像素错位的多幅低分辨率图像重建高分辨率图像的原理是正确的 ,方案是可行的     

重复频率强流电子束的产生和传输实验研究

 电子束真空二极管重复频率运行时,它将表现出与单次运行时不同的特点。在电子束产生过程中,屏蔽半径应尽可能地小,且击穿延时时间较短,故选择石墨作为阴极材料。实验结果表明：在重复频率运行时,当环型阴极环厚较薄时,阴极的发射电流密度较大,因此对阴极的加热效应也加强,等离子体的膨胀速度加快,从而使得二极管阻抗减小,最后几次输出的电子束的电流较大,而电压减小;当重复频率较高时,由于加热效应使得阴极等离子体膨胀速度加快,最后几个脉冲阴极发射能力增强,波形重复性变差;当引导磁场强度增大时,阴极等离子体受到较大的磁场力约束,横向膨胀速度减慢,从而使得电子发射面积减小,总发射电流减小,二极管的阻抗增大。最后取引导磁场为1.5 T,阴极环厚为1 mm,得到重复频率100 Hz、束压827 kV、束流8.22 kA、脉冲波形之间重复性很好的均匀电子束输出。