On the extinction multipole plasmons in gold nanorods

On the basis of the T-matrix formalism and numerical simulations, we derive an explicit rule for partial multipole contributions to the plasmon resonances of gold nanorods at a fixed or random orientation. The parity of a given spectral resonance number n coincides with the parity of their multipole contributions l, where l is equal to or greater than n, and the total resonance magnitude is determined by the lowest multipole contribution. We also investigate the dependence of multipole plasmons on the size, shape, and orientation of nanorods with respect to the polarized incident light. It is shown that the multipole resonance wavelengths as a function of the aspect ratio divided by the resonance number collapse onto one linear scaling curve. This scaling is explained by using the plasmon standing wave concept introduced by Schider et al. [Plasmon dispersion relation of Au and Ag nanowires. Phys Rev B 2003;68:155427].     

Electron cyclotron resonance heating in a short cylindrical plasma system

Electron cyclotron resonance (ECR) plasma is produced and studied in a small cylindrical system. Microwave power is delivered by a CW magnetron at 2.45 GHz in TE¹⁰ mode and launched radially to have extraordinary (X) wave in plasma. The axial magnetic field required for ECR in the system is such that the first two ECR surfaces (B = 875.0 G andB = 437.5 G) reside in the system. ECR plasma is produced with hydrogen with typical plasma density n^e as 3.2 × 10¹⁰ cm^-3 and plasma temperature T^e between 9 and 15 eV. Various cut-off and resonance positions are identified in the plasma system. ECR heating (ECRH) of the plasma is observed experimentally. This heating is because of the mode conversion of X-wave to electron Bernstein wave (EBW) at the upper hybrid resonance (UHR) layer. The power mode conversion efficiency is estimated to be 0.85 for this system. The experimental results are presented in this paper.     

Monte carlo simulation of the electron paramagnetic resonance spectrum displayed by copper ceruloplasmin at 77 K

Summary Human ceruloplasmin contains several intrinsic copper ions, some of them being paramagnetic. The presence of two classes of paramagnetic Cu²⁺ ions (type I and type II) has been suggested, the two types having significantly different spectroscopic features. However, there are conflicting reports both on the ratio of the number of type-I to type-II Cu²⁺ and on their EPR spectroscopic parameters. By using a Monte Carlo method we obtained the best fit of the experimental spectrum with a synthesized composite spectrum generated by two type-I Cu²⁺ (type I _a and type I _b , possessing slightly different spin Hamiltonian parameters) and by one type-II Cu²⁺. Correspondingly, the EPR spectroscopic parameter (viz. theg-tensors, hyperfine couplings, line widths and molar fractions) together with their accuracies were determined.

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Riassunto La ceruloplasmina umana contiene diversi ioni Cu²⁺ alcuni dei quali sono paramagnetici. Di questi ne sono stati ipotizzati due tipi (tipo I e tipo II), ognuno dei quali con caratteristiche spettroscopiche diverse. Tuttavia esistono nei lavori precedenti discordanze sia sul numero di ioni Cu²⁺ che sui loro parametri EPR. Si è usato il metodo Montecarlo per ottenere il best fit dello spettro EPR della ceruloplasmina. Lo spettro simulato è risultato la somma di tre spettri, 2 di tipo I (tipo I _a e tipo I _b ) e 1 di tipo II. Sono stati così determinati i parametri relativi all'hamiltoniana di spin del sistema e le loro deviazioni standard.

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Резюме Человеческий церулоплазмин содержит несколяко собственных ионов меди, некоторые из которых являются парамгнитными. Предполагается наличие двух классов парамгнитных Cu²⁺ ионов (тип I и тип II). Эти два типа имеют существенно различные спектроскопические свойства. Однако имеются противо-речивые публикации об отношении числа ионов Cu²⁺ типа I к числу ионов Cu²⁺ типа II и об их ЭПР спектроскопических параметрах. Исполязуя метод Монте-Карло, мы получаем наилучшее согласие экспериментального спектра с синтесированным составным спектром, образованным спектрами Cu²⁺ типа I (тип I _a и тип I _b имеющие слегка различные параметры спинового Гамилятониана) и одного спектра Cu²⁺ типа II. Определяются ЭПР спектроскопические параметы (а именно:g-тензоры, сверхтонкие связи, ширины линий и молярные доли).

     

NO的多光子电离谱及跃迁通道的研究

本文对中间共振能级为A~2∑~+、F~2⊿、H~2∑和H’~3H态的NO四光子电离谱作了转动谱线标识及研究.提出了双共振及碰撞电离模型,以解释实验中出现的强度反常谱线.     

Geometric Analysis and Symbol Calculus: Fourier Transform Magnetic Resonance Imaging and Wavelets

Due to its unequalled advantages, the magnetic resonance imaging (MRI) modality has truly revolutionized the diagnosis and evaluation of pathology. Because many morphological anatomic details that may not be visualized by other high tech imaging methods can now be readily shown by diagnostic MRI, it has already become the standard modality by which all other clinical imaging techniques are measured. The unique quantum physical basis of the MRI modality combined with the imaging capabilities of current computer technology has made this imaging modality a target of interdisciplinary interest for clinicians, physicists, biologists, engineers, and mathematicians. Due to the fact that MRI scanners perform corticomorphic processing, this modality is by far more complex than all the other high tech clinical imaging techniques. The purpose of this paper is to outline a phase coherent wavelet approach to Fourier transform MRI. It is based on distributional harmonic analysis on the Heisenberg nilpotent Lie group G and the associated symplectically invariant symbol calculus of pseudodifferential operators. The contour and contrast resolution of MRI scans which is controlled by symplectic filter bank processing gives the noninvasive MRI modality superiority over X-ray computed tomography (CT) in soft tissue differentiation.     

受迫振动的能量共振

通过对受迫振动系统的功能，势能和总能量的分析，推证了受迫振动系统能量共振的频率，并对其结果进行了分析讨论。     

Magnetic properties of the low dimensional spin system (VO)PO:ESR and susceptibility

Experimental results on magnetic resonance (ESR) and magnetic susceptibility are given for single crystalline (VO)₂P₂O₇. The crystal growth procedure is briefly discussed. The susceptibility is interpreted numerically using a model with alternating spin chains. We determine J =51 K and . Furthermore we find a spin gap of meV from our ESR measurements. Using elastic constants no indication of a phase transition forcing the dimerization is seen below 300 K. Received: 22 December 1997 / Accepted: 17 March 1998     

探测结构材料应力的频率谐振技术

设计和建造大型磁体系统(包括常温和低温超导磁体)是目前核聚变工程中重要的问题之一。而磁体研制的核心问题都与强大机械力的存在有关。因此开展对磁体及结构材料应力的研究工作就显得特别重要。 近年来开始应用声学方法研究磁体中与力有关的问题(例如用声发射技术探测超导磁体的工作情况),已取得了有希望的结果。我们对低温与超导磁体中常用结构材料进行过声发射实验研究,也对目前尚存在争论的“磁体猝灭的声发射预测”问题进行了实验研     

N NMR in AlN and BN

A characterisation by ¹⁴N NMR of the binary nitrides AlN and BN is presented. Both the static and magic angle spinning (MAS) lineshapes have been investigated in order to determine, or set upper limits on, the nuclear quadrupole coupling (C_q) at the nitrogen site. Additional data are given for the C_q values at the Al and B sites. A comparison is made with other similar (mainly wurtzite) binary compounds for which C_q is known at each atomic site.     

Resonance Raman spectroscopy of polyene compounds (multimode systems). Polyacetylene synthesized from cyclooctatetraene

Specific features of the excitation spectra of resonance Raman (RR) lines in multimode systems were characterized. Based on this, the spectra, the structure, and the composition of polyacetylene (PA) synthesized by polymerization of cycloocta-1,3,5,7-tetraene in the presence of metathesis catalysts were investigated. A dependence of frequencies and intensities of the C-C and C=C stretching lines on the exciting light wavelength was found and explained by broad distribution of defect-free conjugated polymer segments in the PA samples studied on the number of double bonds incorporated in them. A procedure for the calculation of the distribution functions and of the shapes of RR lines was proposed. These functions are bimodal. A reversiblecis-trans-transition was discovered in the PA samples not subjected to heat treatment, which was attributed to the presence of macrocyclic polyene structures.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 2016–2020, August, 1996.