量子通信研究进展与应用

量子通信利用量子信道进行信息的编码、传输和处理,具有安全性高和信道容量高等特点。量子保密通信以信息安全为主要目的,包括量子密钥分发、量子安全直接通信和量子秘密共享等模式。利用量子纠缠,量子隐形传态根据事先已经分发的纠缠粒子对实现不传输实物粒子而传输未知粒子的状态,量子密集编码通过传输一个粒子而实现两个粒子信息的传输,这些是经典通信无法实现的任务。文章简单介绍量子通信的内容和进展情况。     

船用烟火信号光强测试技术研究

救生信号弹是民用船只海上救生的必要设备,其质量的好坏直接关系到人身安全。根据照度距离平方反比定律,结合光电技术和计算机辅助技术,研究救生信号弹的信号光强测试,构建测试系统。通过编写的测试软件,将测得的信号直接输入计算机,并直观地显示结果。实现了简易、快速测量救生信号弹发光强度和遮光率的目的。实验证明：该系统稳定可靠,并且符合生产企业生产过程在线检测的需要。     

基于MPC8270的处理器板卡设计

随着海洋地震勘探发展,为了实现海洋地震勘探采集数据的实时传输和处理,设计了一种基于MPC8270的地震数据采集处理板卡;根据海洋地震数据采集处理的实时性和大数据量要求以及MPC8270处理器的特性,设计了基于MPC8270和FPGA的CPCI总线通信结构,能够实现地震数据的高速实时传输;详细介绍了MPC8270的关键外围电路、FPGA及CPCI总线电路的硬件设计及实现方法,并在实际应用中给出了板卡嵌入式操作系统VxWorks配置的实现方式;板卡以MPC8270作为核心处理器,以FPGA为控制核心电路,以VxWorks为实时操作系统,实现地震数据的高速处理和CPCI总线实时传输功能;经过多次实验室内部测试及海上实际生产应用,结果表明地震数据采集处理板卡能够实现地震数据的高速处理和实时传输,并且板卡性能稳定可靠;板卡的设计简单,结构通用,对数据处理、总线控制和信息交换等领域相关系统的开发具有一定的参考价值。     

基于Cayley图上量子漫步的匿名通信方案

信息安全是信息化社会国家安全的基石与命脉,而匿名量子通信是保护信息安全的重要通信方式之一.利用量子漫步随机性有效解决身份信息泄露等敏感问题,本文提出一种基于Cayley图上量子漫步的匿名通信方案.首先,通信双方隐藏自身身份信息,发送方Alice通过逻辑或操作匿名选择接收方Bob.其次,可信第三方与通信双方利用BB84协议生成和分发安全密钥, Alice根据安全密钥对信息序列进行加密,获得盲化信息; Bob利用联合Bell态测量和安全密钥进行签名,可信第三方验证签名信息.再次,可信第三方依据傅里叶变换计算Bob量子漫步的位置概率分布函数,将概率最大值对应的位置信息转换为确认帧发送给Alice;Alice利用量子降维压缩算法减少传输信息比特数,并利用安全密钥完成信息加密后将信息传输至确认帧表示的位置, Bob利用量子漫步搜索位置节点获取传输信息,完成匿名量子通信.最后,对方案进行安全分析,并给出200个节点Cayley图的数值仿真结果,漫步10步时,第6个节点的概率最大为45.31%.根据仿真结果,本方案通信过程中Bob漫步10步时被窃听到具体位置的概率近似为6×10~(–7)%.     

基于量子隐形传态的量子保密通信方案

量子保密通信包括量子密钥分发、量子安全直接通信和量子秘密共享等主要形式.在量子密钥分发和秘密共享中,传输的是随机数而不是信息,要再经过一次经典通信才能完成信息的传输.在量子信道直接传输信息的量子通信形式是量子安全直接通信.基于量子隐形传态的量子通信(简称量子隐形传态通信)是否属于量子安全直接通信尚需解释.构造了一个量子隐形传态通信方案,给出了具体的操作步骤.与一般的量子隐形传态不同,量子隐形传态通信所传输的量子态是计算基矢态,大大简化了贝尔基测量和单粒子操作.分析结果表明,量子隐形传态通信等价于包含了全用型量子密钥分发和经典通信的复合过程,不是量子安全直接通信,其传输受到中间介质和距离的影响,所以不比量子密钥分发更有优势.将该方案与量子密钥分发、量子安全直接通信和经典一次性便笺密码方案进行对比,通过几个通信参数的比较给出各个方案的特点,还特别讨论了各方案在空间量子通信方面的特点.     

基于单光子双量子态的确定性安全量子通信

量子通信是量子科学技术的一个重要研究领域,是一种利用量子力学原理,能够在合法各方之间安全地传输私密信息的通信方式.基于单光子的确定性安全量子通信通常需要在发送方和接收方之间来回两次传输单光子态,并利用局域幺正变换加载信息.本文提出了一种单向传输单光子态的确定性安全量子通信方案.发送方利用单光子的极化和time-bin两自由度构成的两组共轭基矢量来编码经典逻辑比特.接收方通过设计合适的测量装置可以在发送方辅助下确定性地获取比特信息并感知窃听,从而实现信息的确定性安全传输.另外,我们的协议使用线性光学元件和单光子探测器,可以在当前的量子通信装置上实现.     

基于光场量子态的连续变量量子信息处理

连续变量量子信息是量子信息科学研究的一个重要内容。基于光学模的连续变量量子信息处理,以光场量子态为量子资源,结合各种量子操控手段,完成信息的传输和处理。本文简要介绍用于连续变量量子信息处理的光量子态的概念、制备方法和操控手段,以及连续变量量子通信、量子计算和量子纠错方面的研究进展和发展趋势。     

语言通信中的一些声学问题

一、概 述 语言通信是研究两处或多处进行语言信息交换的学科.电话通信是语言通信中的一种最主要的手段,它与语言声学、生理声学、电声学和建筑声学等有着密切的关系.本文扼要介绍电话通信中经常遇到的一些声学问题. 二、电话传输质量的主观评价 电话传输系统的传输质量主观评价标准和     

基于单光子的单向量子安全通信协议

提出了基于单光子的单向量子安全通信方案.发送方在对信息序列进行编码操作之前首先将其和随机序列进行异或操作并插入校验序列.接收方收到光子后对其进行延迟,此后发送方公布编码基从而使接收方在正确的基下进行测量.接着双方通过校验序列判断信道的安全性,如果信道安全,则发送方公布接收方有测量结果的位置所对应的随机序列,接收方由此恢复出信息序列;如果信道不安全,窃听者所获得的只是随机的发送序列,信息序列仍然是安全的.此协议与双向通信协议相比具有传输效率高、 易于实现等优点. 关键词： 量子密码 量子安全通信 单光子 单向通信     

无边带信息的多输入多输出正交频分复用水声通信图样选择峰均比抑制算法

针对多输入多输出正交频分复用 图样选择 峰均比(peak-to-average-power-ratio PAPR)抑制算法需要传递边带信息的缺点, 提出了一种无边带信息传输的图样选择峰均比抑制算法. 该算法利用不同分布图样的梳状导频携带加扰相位序列选择信息, 结合浅海水声信道的稀疏特性在接收端对加扰图样进行自主区分, 实现了无边带信息的图样选择峰均比抑制.仿真和水池实验结果证实: 无边带信息传输的图样选择峰均比抑制算法可以在不损失PAPR抑制性能的前提下, 准确解算出传输相位序列选择信息、对抗突发噪声、实现无边带信息传输的可靠水声通信. 关键词： 水声通信 正交频分复用 峰均功率比 边带信息     

Pressure effects on 2p5 3p - 2p5 3d transitions in neon

The collisional broadening and shift of four spectral lines of neon (747.2, 748.8, 753.5, 754.4 nm) arising from 2p⁵ 3p - 2p⁵ 3d transitions, emitted from a low-pressure glow discharge in pure neon and neon-helium mixtures have been measured using a Fabry-Perot interferometer. The values of pressure broadening and shift coefficients are determined and analyzed in terms of the impact theory.     

Resonant raman effect of hematoporphyrin IX in the α, β absorption band of the Q(π→π*) electronic transition

Summary Resonant Raman spectra of hematoporphyrin IX have been obtained in methanol, acetone and acetic acid. Excitation RR profiles show that intensity enhancements, due to the vibronic excitation process, are active for some normal vibrations of the macrocycle and for motions of the lateral groups. Line-width-lifetime correlations and molecular-association processes are discussed.

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Riassunto Gli spettri di risonanza Raman di ematoporfirina IX sono stati ottenuti in soluzioni di metanolo, acetone e acido acetico. I profili di eccitazione di risonanza Raman mostrano che aumenti d'intensità, dovuti al processo di eccitazione degli stati vibronici, sono osservabili per alcuni modi normali del ?macrociclo? e per alcune vibrazioni di gruppi appartenenti ai sostituenti laterali nel macrociclo. Le correlazioni tra ampiezza di riga e tempo di vita dello stato vibronico, nonché i processi di associazione molecolare, sono discussi nel presente lavoro.

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Резюме Получаются резонансные рамановские спектры для гематопорфирина IX в метаноле, ацетоне и уксусной кислоте. Профили резонансного рамановского возбуждения обнаруживают, что увеличение интенсивности, обусловленные процессами вибрационного возбуждения, являются наблюдаемыми для некоторых нормальных мод ?макроцикла? и для движений поперечных групп. Обсуждаются корреляции между шириной линии и временем жизни и процессы объединения молекул.

     

ROSETTA and FIRST: Two cornerstone missions of ESA long-term space science programme

Summary The paper reviews the objectives and status of definition of ROSETTA (Comet Nucleus Sample Return) and FIRST (Far Infrared Space Telescope), which are two cornerstone missions of the ESA long-term scientific programme. ROSETTA is a joint ESA/NASA programme and it will address problems centered on the origin of planetary material and the pre-biotic evolution of organic matter. The ROSETTA spacecraft will be launched in 2001; it will land into the nucleus of comet Churyumov-Gerasimenko, take about 10 kg of cometary samples (ice, dust, organics) and will return the Earth in 2008. FIRST will explore the 10 μm to 1 mm region of the electromagnetic spectrum, where a large number of very important atomic and molecular spectral lines are hosted. The major scientific objectives are the physics of the interstellar medium of the star formation and cosmological studies. The mission is based on a 4.5 to 8 m telescope equipped with imaging spectrometers and operating as a near-real-time observatory from a high elliptical orbit of 24 h period. Low operating temperatures for the payload will be achieved by using a combination of mechanical coolers and a liquid helium cryostat. To speed up publication, the proofs were not sent to the authors and were supervised by the Scientific Committee.     

Coherent hyper-raman scattering: An application to amorphous materials

Summary Coherent Hyper-Raman scattering from hot polaritons gives conspicuous advantages with respect to thermal Hyper-Raman scattering. It allows a precise study of polar modes in liquids and amorphous materials, where they are forbidden in Raman scattering. We give a classical theory for this nonlinear process and the results are applied to the study of the polariton at 1065 cm⁻¹ in amorphous quartz. The experimental data, having a precision two orders of magnitude better than in previous studies, show that the polaritons propagate in the glass with a well-defined wave vector. The dispersion curve of the polariton and its width in the wave vector space can be described by means of a multioscillator model taking into account the inhomogenous width of the levels originated from disorder.

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Riassunto La diffusione Hyper-Raman coerente da polaritoni eccitati mediante assorbimento di un impulso laser infrarosso offre notevoli vantaggi rispetto alla diffusione Hyper-Raman termica. Essa consente uno studio preciso dei modi polari negli amorfi e nei liquidi dove risultano proibiti nelle transizioni Raman. Viene formulata una teoria classica per questo tipo di diffusione coerente ed i risultati vengono applicati allo studio sperimentale del polaritone a 1065 cm⁻¹ nel quarzo amorfo. I dati sperimentali, con una precisione di due ordini di grandezza migliore che nei precedenti studi, mostrano che il polaritone si propaga nel vetro con un ben definito vettore d’onda. La curva di dispersione del polaritone e la sua larghezza nello spazio dei vettori d’onda può essere descritta mediante un modello a più oscillatori, tenendo conto dell’allargamento inomogeneo dei livelli derivante dal disordine.

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Резюме Когерентное гипер-рамановское рассеяние на горячих поляритонах дает явные преимущества по сравнению с тепловым гиперрамановских рассеянием. Этот подход поэволяет исследовать полярные моды в жидкостях и аморфных материалах, где они эапрешены при рамановском рассеянии. Мы раэвиваем классическую теорию для этого нелинейного процесса и полученные реэультаты применяются к иоследованию псляритона при 1065 cm⁻¹ в амопфном кварце. Эксперименталвные данные, имеюшие точносты на два порядка лучше предыдуших реэультатов, покаэывают, что поляритоны распространяются в стекле с хорошо определенным волновым вектором. Дисперсионная кривая поляритона и ее шириина в пространстве волновых векторов может быты олисана с помощью многоосцилляторной модели, которая учитывает неоднородную ширину уровней, воэникющую иэ-эа неупорядоченности.

     

FEL gain in the pulsed regime: a comparison between numerical and analytical results

Summary In this paper we present simple and general formulae for the FEL gain in the pulsed regime including both the longitudinal mode coupling and the lethargy effect. Such relations, obtained from a numerical integration of the pulse propagation equations, are then compared to similar expressions obtained analitycally in the limiting case of the long bunch approximation and the agreement is shown to be excellent.

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Riassunto In questo lavoro vengono derivate formule semplici e generali relative al guadagno FEL in regime impulsato. Tali formule tengono conto dell'accoppiamento tra i modi longitudinali e dell'effetto di letargia. Le relazioni di cui sopra sono ottenute nell'ambito di una trattazione numerica delle equazioni di propagazione degli impulsi e sono poi comparate ad analoghe espressioni ottenute per via analitica nel caso limite di pacchetto di elettroni lungo. Si dimostra come l'accordo sia particolarmente buono.

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Резюме В зтой статье мы приводим простые и общие формулы для усиления для лазера на свободных злектронах в импульсном режиме, учитывая связь продольных мод и зффект летаргии. Зти соотношения, полченные с помощью численного интегрирования уравнений распространения импульса, затем сравниваются с аналогичными выражениями, полученными аналитически в предельном случае приближения длинного сгустка, и получается хорошее согласие.

     

The atmosphere of Titan and the Huygens atmospheric structure instrument

Summary The Huygens Atmospheric Structure Instrument (HASI) is a multisensor package which has been designed to measure the physical quantities characterizing the atmosphere of Titan. After a short summary of the available information on Titan's atmosphere, the HASI is described as well as its capabilities to improve our knowledge of the larger Saturnian satellite. Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990.     

Inhomogeneous broadening effects in high-gain free electron laser operation: A simple parametrization

Summary In this paper we present a simple parametrization of the effects of gain degradation induced in high-current FELs by the inhomogeneous broadenings due to the energy spread and emittances of the electron beam. The parametrization is based on a fitting procedure of the numerical data. The accuracy of the fit is better than 1%.

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Riassunto In questo lavoro si analizzano gli effetti di allargamento inomogeneo in FEL operanti nel regime di alto guadagno. Si presenta una semplice formula che permette di parametrizzare il guadagno in funzione dei parametri inomogenei dovuti allo spread di energia ed alle emittanze. La parametrizzazione è basata su una procedura di interpolazione dei dati numerici. L'accuratezza della interpolazione è migliore dell'1%.

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Резюме В этой работе анлизируется влияние эффектов неоднородного уширения на действие лазера на свободных электронах с высоким усилением. Предлагается простая формула для параметризации коэффициента усиления в зависимости от параметров неоднородного уширения, связанных с разбросом энергии и эмиттанса электронного пучка. Параметризация основана на интерполяции численных данных. Точность интерполяции оказывается лучше 1%.

     

Effect of the incoherent emission on the FEL pulse width

Summary In this paper we discuss the effect of the incoherent spontaneous emission on the FEL pulse width. We analyse the dependence of the laser spatial width on the number of round trips, within the framework of the supermodes’ theory. We also study the distortion induced in the supermode spectrum by the incoherent emission.

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Riassunto Gli autori discutono l’effetto della emissione spontanea incoerente sull’ampiezza dell’impulso laser in un FEL nel corso dell’evoluzione del segnale. Le espressioni riportate sono derivate nel contesto della teoria dei supermodi precedentemente sviluppata relativamente al regime di basso guadagno e piccolo segnale e nell’ipotesi di pacchetto di elettroni lungo.

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Резюме В этой статье мы обсуждаем влияние некогерентного спонтанного нзлучения на ширину импульса в лазере на свободных электронах. Мы анализируем зависимость пространственной ширины импульса лазера от числа пролетов в рамках теории супер-мод. Мы также исследуем дисторсию, индуцированную в спектре супермод из-за некогерентного излучения.

     

Raman spectroscopy in GaS: Zone boundary phonon interactions

Summary A complete polarization analysis of the GaS Raman spectrum, for excitation energies below the indirect energy gap, is reported. In order to assign second-order combinations and defect-induced forbidden modes, that appear in the spectra besides the six well-known Γ-phonons, also IR transmittance and reflectance measurements, for bothE⊥c andE‖c, have been performed. All the available selection rules are applied to both Raman and IR data, allowing to identify the high-symmetry points of phonons involved in the scattering and, when possible, to ascribe the main non-Γ structures of the spectra to the knownK andM point modes. This analysis brings to several new attributions, also ruling out some previous assignments, based on the separate study of either Raman or IR spectra. Work partially supported by M.P.I.     

Dispersed lyotropic phases as carriers for active substances

Summary Smectic mesophases of water-insoluble compounds can be dispersed to form multilayered structures (liposomes). These provide different siters for the solubilization or entrapment of active compounds such as drugs. The specific advantages and drawbacks of these systems are discussed in comparison with those of other carriers for what concerns the aspects of feasibility, versability, encapsulating ratio, shelf life and fatein vivo. The tendency of liposomes to be taken up by particular cells can be exploited in passive targeting. Much effort is devoted now to active targeting of these particles by gearing them with specific ligands. This is still a far cry from the applications of lyotropics in systemic therapy. Topical administration of vesicles offers several advantages which have been identified in the field of skin care products. Experimental data are provided to substantiate this view. Finally it is worthwhile mentioning that vesicles of adequate chemical composition are stable in oil-amphiphile-water systems. This fact raises theoretical questions and at the same time opens new avenues to the development of multicompartment carriers. Paper presented at the ?Meeting on Lyotropics and Related Fields?, held in Rende, Cosenza, September 13–18, 1982.