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Abstract In this study, 0.18 um pitch processed CMOS ICs with multiple thin film layers manufactured by United Microelectronics Corporation were used for the measurement of the surface deformation from the Scanning Electron Microscopy (SEM) images and Digital Image Correlation (DIC). The features of the natural surface were directly used for image correlation. Drift distortion and noises which arise from rasterizing, and the time-dependent nature of SEM image capturing and electromagnetic lenses was considered. A series of translation tests with various magnifications were made. Two SEM images of the sample, one each for before and after translation, were processed to extract the surface displacement from tiny changes in the SEM images of a thin film using DIC. Test results obtained from various sizes of the sub-image, noise filtering process, and the correlation approach were compared. A proper scheme was established for calibration and for obtaining a more accurate result of surface deformation of the CMOS ICs. Graphical abstract Unlabelled Image Highlights • Use of Digital Image Correlation (DIC) on Scanning Electron Microscopy (SEM) images of CMOS-IC for their surface deformation measurement. • Studies the methodology and validation to minimize the DIC errors under SEM • Use for the implementation of surface deformation and strain measurement of CMOS IC with multiple thin layers manufactured using the 0.18 um pitch processes • Guide the proper choice of analysis parameters for the accurate full field displacement measurements. [ABSTRACT FROM AUTHOR]

Examines whether an electromagnetic missile can be launched with a point excitation. Conditions for the presence of an electromagnetic missile; Classification of electromagnetic missiles.

A new pathway to nuclear magnetic resonance (NMR) spectroscopy for picoliter-sized samples (including those kept in harsh and extreme environments, particularly in diamond anvil cells) is introduced, using inductively coupled broadband passive electromagnetic lenses, to locally amplify the magnetic field at the isolated sample, leading to an increase in sensitivity. The lenses are adopted for the geometrical restrictions imposed by a toroidal diamond indenter cell and yield signal-to-noise ratios at pressures as high as 72 GPa at initial sample volumes of only 230 pl. The corresponding levels of detection are found to be up to four orders of magnitude lower compared to formerly used solenoidal microcoils. Two-dimensional nutation experiments on long-chained alkanes, CnH2n+2 (n = 16 to 24), as well as homonuclear correlation spectroscopy on thymine, C5H6N2O2, were used to demonstrate the feasibility of this approach for higher-dimensional NMR experiments, with a spectral resolution of at least 2 parts per million. This approach opens up the field of ultrahigh-pressure sciences to one of the most versatile spectroscopic methods available in a pressure range unprecedented up to now. [ABSTRACT FROM AUTHOR]

This paper presents a new design of tunable liquid lens. The lens was operated by electromagnetic actuation for autofocusing (AF) in miniature cameras and its optical performance was experimentally verified. An electrical voltage was applied to an electric coil inside an electromagnetic system beneath the liquid lens to generate a magnetic field around the electromagnetic system according to Faraday’s law of induction. The magnetic field was used to actuate a ring-type neodymium magnet placed on the top of an elastic membrane in the liquid lens. The sag (sagittal) height of the liquid lens was measured as a function of the applied voltage. The sag height of the lens increased linearly from −1 mm to 0.8 mm when the applied voltage was changed from 0 V to 50 V at 5 V increments. The average variation of the sag height per volt was about 32 μm. The focal length was also measured with respect to the applied voltage by using a custom-built testing system consisting of a laser, mirror, liquid lens, and detection screen. The measured focal length values were compared with the theoretical ones. For imaging tests, a single-object focusing test was first performed by using a sheet of paper with a check pattern. Furthermore, the ability of the liquid lens to distinguish two objects positioned at different distances by changing its focal plane was successfully tested. Finally, the response times of the liquid lens for actuation and relaxation were measured by a high-speed camera and were found to be about 900 ms. [ABSTRACT FROM AUTHOR]

One specific kind of electrically tunable lenses is utilizing curvature change via adjusting input currents which electromagnetically exerts pressure on liquid volume to achieve variable-focusing properties. Nevertheless, the nature of curvature change and refractive index mismatch causes inherent spatial aberrations that severely degrade image quality. The novelty of the presented method lies in the experimental study of optical aberrations, such as root mean square (RMS), Strehl ratio and Zernike coefficients induced from electrically tunable lenses and use of adaptive optics to compensate for the wavefront errors. The optical properties of electrically tunable lens are quantitatively characterized by Shack – Hartmann measurements. Adaptive optics-based scheme is demonstrated for the current range 78–95 mA, resulting in a substantial reduction of the wavefront errors from 0.55, 0.53 to 0.22, 0.2 μm, respectively, corresponding to the focal power tunability of −2.52 to 0.2 diopters. It is experimentally showed that defocus ( Z 5 ) aberration is the most significant one since the changes of lens curvature varies in proportional with changing currents, and can be significantly improved from 0.328 μm to 0.156 μm with adaptive optics. Similar improvements can be found in piston ( Z 1 )/tip ( Z 2 )/tilt ( Z 3 ) aberrations with the integration of adaptive optics. [ABSTRACT FROM AUTHOR]

We present the first demonstration of a proprietary non-contact atmospheric electron beam-induced plasma probe technique for current-based electrical characterization of flat panel display backplanes. Accurate I-V curves were measured and single line defect sensitivity was demonstrated. This technology is expected to greatly benefit AMOLED display fabrication yields. [ABSTRACT FROM AUTHOR]

Fresnel Zone Plate Lenses (FZPLs) are transparent-opaque lenses that filter the desirable phase. The centred Fresnel lenses have a strong back radiation towards the feed. In order to solve this drawback, offset feeding or offset pointing lenses are used. In this work, both offset FZPLs are studied using an optical physics method and experimentally characterized in the millimeter band. Two prototypes have been manufactured and measured, presenting a narrow beamwidth. The characteristics of pointing of this beam are studied depending on the feed gain. This work shows the pointing characteristics of the lenses, simply moving the lens in a plane. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) highly-directive emission system is proposed to enable beam shaping and beam steering capabilities in wideband frequencies. It is composed of an omnidirectional source antenna and several 3D gradient-refractive-index (GRIN) lenses. To engineer a broadband impedance match, the design method for these 3D lenses is established under the scenario of free-space excitation by using a planar printed monopole. For realizations and demonstrations, a kind of GRIN metamaterial is proposed, which is constructed by non-uniform fractal geometries. Due to the non-resonant and deep-subwavelength features of the fractal elements, the resulting 3D GRIN metamaterial lenses have extra wide bandwidth (3 to 7.5 GHz), and are capable of manipulating electromagnetic wavefronts accurately, advancing the state of the art of available GRIN lenses. The proposal for the versatile highly-directive emissions has been confirmed by simulations and measurements, showing that not only the number of beams can be arbitrarily tailored but also the beam directions can be steerable. The proposal opens a new way to control broadband highly-directive emissions with pre-designed directions, promising great potentials in modern wireless communication systems. [ABSTRACT FROM AUTHOR]

Massive multiple-input–multiple-output (MIMO) techniques have been recently advanced to tremendously improve the performance of wireless communication networks. However, the use of very large antenna arrays at the base stations brings new issues, such as the significantly increased hardware and signal processing costs. In order to reap the performance gains of massive MIMO and yet reduce its cost, this paper proposes a novel system design by integrating an electromagnetic (EM) lens with the large antenna array, termed the EM-lens enabled MIMO. The EM lens has the capability of focusing the power of an incident wave to a small area of the antenna array, whereas the location of the focal area varies with the angle of arrival (AoA) of the wave. Hence, in scenarios where the arriving signals from geographically separated users have different AoAs, the EM-lens enabled receiver provides two new benefits, namely, energy focusing and spatial interference rejection. By taking into account the effects of imperfect channel estimation via pilot-assisted training, in this paper, we analytically show that the average received signal-to-noise ratio in both the single-user and multiuser uplink transmissions can be improved by the EM-lens enabled system. Furthermore, we demonstrate that the proposed design makes it possible to considerably reduce the hardware and signal processing costs with only slight degradations in performance. To this end, two complexity/cost reduction schemes are proposed, which are small-MIMO processing with parallel receiver filtering applied over subgroups of antennas to reduce the computational complexity, and channel covariance based antenna selection to reduce the required number of radio frequency chains. Numerical results are provided to corroborate our analysis and show the great potential advantages of our proposed EM-lens enabled MIMO system for next generation cellular networks. [ABSTRACT FROM PUBLISHER]

Electron gun is being considered as the main source of electron generation in microwave tubes and linear accelerators. In this paper, after confirming of CST validation, the thermionic electron gun used in the available electron linear accelerator which can accelerate electrons to 50 keV is investigated. The electrodes of this gun are designed so that electron beam with the initial radius of 3.9 mm finally reaches the current of 10 mA at the focusing point. For the purpose of convergence and steering the beam at a distance of 290 mm from the cathode, where pre-buncher is situated, electromagnetic focusing lenses are placed after the electrodes of the above-mentioned gun. This system focuses the beam to radius of 2.1 mm at the location of the pre-buncher. Also, changes in the effective parameters of the electron gun under the influence of the magnetic field are studied. Finally, changes in the current density were evaluated for changes in the cathode materials and temperature. Determining the maximum allowable operating temperature range for the change of emitter material is another achievement. [ABSTRACT FROM AUTHOR]

The article reports on a study that analyzes symptoms caused by different sugar beet diseases via hyperspectral imaging (HSI). It states HSI offers high potential as a non-invasive diagnostic tool for disease detection. It reports on the use of light microscopy to describe the morphological changes in the host tissue due to pathogen colonisation.

Abstract: In electron microscopy, a large field of view is commonly captured by taking several images of a sample region and then by stitching these images together. Non-linear lens distortions induced by the electromagnetic lenses of the microscope render a seamless stitching with linear transformations impossible. This problem is aggravated by large CCD cameras, as they are commonly in use nowadays. We propose a new calibration method based on ridge regression that compensates non-linear lens distortions, while ensuring that the geometry of the image is preserved. Our method estimates the distortion correction from overlapping image areas using automatically extracted correspondence points. Therefore, the estimation of the correction transform does not require any special calibration samples. We evaluate our method on simulated ground truth data as well as on real electron microscopy data. Our experiments demonstrate that the lens calibration robustly corrects large distortions with an average stitching error exceeding 10 pixels to sub-pixel accuracy within two iteration steps. [Copyright &y& Elsevier]

Otto Scherzer was one of the pioneers of theoretical electron optics. He was coauthor of the first comprehensive book on electron optics and was the first to understand that round electron lenses could not be combined to correct aberrations, as is the case in light optics. He subsequently was the first to describe several alternative means to correct spherical and chromatic aberration of electron lenses. These ideas were put into practice by his laboratory and students at Darmstadt and their successors, leading to the fully corrected electron microscopes now in operation. [ABSTRACT FROM PUBLISHER]

Abstract: In this work we present advances in the design of lenses based on left-handed extraordinary transmission metamaterials which provide high transmission and focusing despite the subwavelength size of their constituent apertures. Due to the effective negative index of refraction of the close-stack of subwavelength hole arrays, concave profiles are required for focusing instead of the convex geometries of dielectric lenses. An analysis of the foci produced by plano- and bi-concave lens is carried out. [Copyright &y& Elsevier]

Abstract: This work presents an analysis of the lens system in a thermionic scanning electron microscope (SEM) using a numerical computation and an optics-based calculation. The behaviors and characteristics of the electron beam are analyzed and the focusing capability is investigated. The beam spot size is estimated by calculation and proved by experiment. The characteristics and properties determining the SEM performance are investigated for various design parameters through a numerical analysis and an optics-based calculation. Particularly, a combination of two approaches gives more detailed information than a single approach in investigating an extremely small beam spot by demagnification through the electromagnetic lens system in a SEM column. [Copyright &y& Elsevier]

Abstract: The effect of the chromatic aberration coefficient in a spherical aberration - corrected electromagnetic lens on high-resolution high-angle annular dark field (HAADF) scanning transmission electron microscope (STEM) images is explored in detail. A new method for precise determination of the coefficient is demonstrated, requiring measurement of an atomic-resolution one-frame through-focal HAADF STEM image. This method is robust with respect to instrumental drift, sample thickness, all lens parameters except , and experimental noise. It is also demonstrated that semi-quantitative structural analysis on the nanometer scale can be achieved by comparing experimental - corrected HAADF STEM images with their corresponding simulated images when the effects of the coefficient and spatial incoherence are included. [Copyright &y& Elsevier]

Analytical design procedures, numerical simulations and preliminary experimental results of a dielectric lens concentrating the field on a target are discussed. A quarter spherical electromagnetic lens with subsequent layers is used to obtain better focusing, smaller spot size and elimination of the reflection at the second focal point of a prolate-spheroidal impulse radiating antenna for skin cancer treatment. [ABSTRACT FROM AUTHOR]

Measurements of the neutral current cross sections for deep inelastic scattering in e− p collisions at HERA with a longitudinally polarised electron beam are presented. The single-differential cross-sections d σ/ dQ2, d σ/ dx and d σ/ dy and the double-differential cross sections in Q2 and x are measured in the kinematic region y<0.9 and Q2>185 GeV2 for both positively and negatively polarised electron beams and for each polarisation state separately. The measurements are based on an integrated luminosity of 169.9 pb−1 taken with the ZEUS detector in 2005 and 2006 at a centre-of-mass energy of 318 GeV. The structure functions $x\tilde{F_{3}}$ and xF are determined by combining the e− p results presented in this paper with previously measured e+ p neutral current data. The asymmetry parameter A− is used to demonstrate the parity violating effects of electroweak interactions at large spacelike photon virtuality. The measurements agree well with the predictions of the Standard Model. [ABSTRACT FROM AUTHOR]

We propose a simple transformation method of two different kinds of electromagnetic waves using metamaterials. We design the electromagnetic parameters with spatial variations to control the phase speeds of waves in different directions. Then we investigate the transformation from cylindrical and spherical waves to plane waves. Full-wave numerical simulations validate the proposed method. Comparing with the optical-transformation approach, the proposed structures are much easier to be realized, which can be used either as high-performance antennas or focusing lenses. [ABSTRACT FROM AUTHOR]

Abstract: Results of coupled-mode theory for the study on coaxial gyrotron with two electron beams (CGTB) are given. The beam–wave interactions of single-mode and dual-mode CGTB are discussed in details. Compared with the coaxial gyrotron with one beam (CGOB), the dual-mode CGTB has distinguished advantages: the fundamental and high harmonic can be enhanced due to the coupling between two beams. [Copyright &y& Elsevier]

Abstract: A mid-infrared free electron laser (FEL) has been constructed for energy science in the Institute of Advanced Energy, Kyoto University. The FEL system consists of a compact S-band Linac and an undulator to generate 4–13μm coherent mid-infrared radiations. The Linac consists of a 4.5 cell rf gun with a thermionic cathode and a 3-m traveling-wave-type accelerator tube fed by 10MW and 20MW rf power, respectively. We have succeeded to produce 40MeV, 40mA and 3μs electron beams. Last December, the 9.2μm spontaneous emission from the undulator generated by 29.5MeV electron beams was observed for the first time. Further optimization parameters of both the electron beam and the optical cavity are being pursued for an FEL lasing in the near future. [Copyright &y& Elsevier]

The KLn dielectronic recombination processes of trapped highly charged B-like through He-like Cu ions are studied theoretically, and the theoretical results are used to analyse our previous experimental data at Heidelberg electron beam ion trap (EBIT). The theoretical resonant positions agree with the experimental resonant positions to a precision of 0.4%, in comparison with the resonant positions of those highest peaks between theory and experiment. The experimental spectra are then fitted using a formula with the theoretical resonant energies and strengths, the result shows good overall agreement between theory and experiment over a wide electron energy range. The distribution of highly charged states is obtained from the fitting parameters. [ABSTRACT FROM AUTHOR]

Abstract: In situ temperature dependent energy-dispersive structural and magnetic study of electron beam evaporated Fe/Al multilayer sample (MLS) has been investigated. The structural studies show the formation of an intermixed FeAl transition layer of a few nanometers thick at the interface during deposition, which on annealing at 300°C transforms to B2FeAl intermetallic phase. Magnetization decreases with increase in temperature and drops to minimum above 300°C due to increase in anti-ferromagnetic interlayer coupling and formation of nonmagnetic FeAl phase at the interface. The Curie temperature (T c) is found to be 288°C and is much less than that of bulk bcc Fe. [Copyright &y& Elsevier]

Common optical methods for dimension measurement apply an image sensor with a lens. The presence of the lens in the camera (and sometimes in the employed illuminator as well) increases the total dimensions of the measuring setup. Furthermore, the aberrations of the lens represent a source of uncertainty. In order to simplify the measuring setup and to reduce its overall dimensions, the method proposed in this paper applies a measuring setup that contains no lens—it employs an image sensor without a lens and two point light sources that illuminate the measured object. In this paper, the application of this method for dimension measurement of objects with a circular cross section is described. In addition, several issues related to the method's implementation are discussed, and its performance is illustrated using experimental results. [ABSTRACT FROM AUTHOR]

The growth rate of the filamentation instability triggered when a diluted cold electron beam passes through a cold plasma is evaluated using the quantum hydrodynamic equations. Compared with a cold fluid model, quantum effects reduce both the unstable wave vector domain and the maximum growth rate. Stabilization of large wave vector modes is always achieved, but significant reduction of the maximum growth rate depends on a dimensionless parameter that is provided. Although calculations are extended to the relativistic regime, they are mostly relevant to the nonrelativistic one. [ABSTRACT FROM AUTHOR]

Based on the vectorial structure of non-paraxial electromagnetic beam and the non-paraxial vectorial moment theory of light beam propagation, the beam waists, the divergence angles and the beam propagation factors of TE and TM terms have been presented for non-paraxial TE vector Gaussian beam. The formulae obtained are further discussed at the highly non-paraxial and paraxial cases. Their respective maximum divergence angles are given at the highly non-paraxial case. When reducing to the paraxial case, the beam propagation factors of TE and TM terms are smaller than unity, which results from their special energy flux distribution. As TE and TM terms can be detached in the far field, they can be applied in the optical storage and collimation domains. [ABSTRACT FROM AUTHOR]

Results are presented from experimental studies of the formation of the energy spectra of the electron beams ejected in the axial direction from a Penning discharge. The main features of the axial evolution of the time-averaged energy spectra of anomalously fast electrons are determined. The presence of several groups of electrons with different energies is revealed and explained. The influence of the electrode geometry, the difference between the cathode potentials, and the atomic mass of the working gas on the energy spectra of the ejected electron beams is investigated. A physical model describing the formation of the energy spectra of anomalously fast electrons in Penning-type gas-discharge systems is proposed. [ABSTRACT FROM AUTHOR]

Abstract: The radiolysis of methane (0.7MeV electron beam) was studied as a function of its concentration at two doses: 5 and 20kGy. In both cases the G (–CH4) value raised with the increase of the substrate concentration. Thereby the yields observed at 20kGy are much lower, because of recombination processes. Results are also reported on the conversion of the gas mixture CH4:CO2:He=1:1:1 into synthetic gas (H2/CO) at 500°C, using two catalysts : (N5) and (N20), containing 5wt% Ni and 20wt% Ni, respectively, supported on γ-Al2O3. In an experimental series the catalysts (N5) and (N20) were treated by irradiation (4MGy dose) before use. The highest conversion yields (above 35%) were observed by implementation of N5 and N20 catalyst at 500°C under the influence of electron beam radiation. [Copyright &y& Elsevier]

The focusing action of refractive cylindrical microlens is investigated based on the rigorous electromagnetic theory with the use of the boundary element method. The focusing behaviors of these refractive microlenses with continuous and multilevel surface-envelope are characterized in terms of total electric-field patterns, the electric-field intensity distributions on the focal plane, and their diffractive efficiencies at the focal spots. The obtained results are also compared with the ones obtained by Kirchhoff's scalar diffraction theory. The present numerical and graphical results may provide useful information for the analysis and design of refractive elements in micro-optics. [ABSTRACT FROM AUTHOR]

It has hitherto been widely believed that no scanning electron microscope was built after those of von Ardenne and Zworykin and before the McMullan instrument. In fact a scanning instrument was constructed in France in 1944-46 and two micrographs obtained with it were published. [ABSTRACT FROM AUTHOR]

Several authors have recently exhibited the focusing activity in the domain of so-called electromagnetic lenses. These lenses are parallel-plate layers of metamaterials whose properties can be described in terms of negative index of refraction. Known works on this subject refer to 2D structures. This work is our first attempt to show the focusing effect by a parallel-plate layer of a 3D metamaterial, whose approximate analytical model was suggested before. The mini-band of propagation and the field distribution across the focal spot are in qualitative agreement with this previous theory. [Copyright &y& Elsevier]

A two-stage algorithm for reconstructing images made up of point sources is proposed and applied to images of the gravitational lens QSO 2237+0305 obtained with the 1.5-m telescope of the Maıdanak Observatory. In the first stage, a modified Tikhonov regularization algorithm is used to split an image with a high signal-to-noise ratio into two parts, corresponding to numerical galaxy and quasar components. In the second stage, the astrometric and photometric characteristics of the individual images of the gravitational-lens system are determined using information about the brightness distribution in the galaxy and a least-squares fit. The two-stage algorithm substantially reduces the time required for the image analysis. A comparison of our method with CLEAN is presented.© 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

Tom Mulvey's life divides naturally into three periods: his early years, wartime experiences and immediately post-war studies, which brings us to about 1948; the years with Metropolitan­Vickers and AEI, which he left in 1965; and the Aston years, as Readers, Professor and Emeritus Professor, which he is toady. In this essay, his many contributions to electron optics are recapitulated against a background of service to the scientific community ad paternal guidance of many foreign students far from their homes. INSET: Tom Mulvey. [ABSTRACT FROM AUTHOR]

Electromagnetic profiling and groundwater sampling on Sugarloaf Key and Little Torch Key in the Lower Keys of Florida show that these small, low-lying islands support only brackish-water lenses. On both islands, the lenses have central cores with lower salinities surrounded by areas of increasing salinity. The uppermost few meters of these central zones are uniform and slightly brackish (∼3 ppt) year-round on Sugarloaf Key. On Little Torch Key, which is smaller, there is a similar central, uniform brackish zone during the wet season, with salinity slightly higher than on Sugarloaf Key. These lenses are similar in form to many freshwater lenses, except that the central zone is slightly brackish rather than fresh. During the dry season Little Torch Key loses the central brackish zone, and salinities increase approximately linearly with depth. This dry-season pattern, in which the freshwater/saltwater mixing zone effectively extends throughout the lens, is similar to that documented on Enjebi Island on the Enewetak Atoll. Seasonal variations on Little Torch Key are less evident outside the central zone. The central lower-salinity core on Sugarloaf Key coincides with elevations > 0.8 m. Using vegetation as a proxy for elevation, the central zone corresponds to the highest elevations on Little Torch Key as well. Tidal efficiencies on Sugarloaf Key indicate the tidal signal propagates through the high-permeability, buried Key Largo Limestone, and then upward through the overlying lower permeability Miami Limestone that contain the lenses. Mixing driven by tidal pumping is likely responsible for the absence of true freshwater lenses on these islands. [ABSTRACT FROM AUTHOR]

In this paper, fifth-order geometric aberrations of round electron lenses have been restudied. Improved analytical formulae of the aberration coefficients were derived by the computer algebra software—Mathematica—and their correctness verified by cross-checking with numerical integration and differential algebraic techniques for a given electromagnetic lens. [ABSTRACT FROM AUTHOR]

In this paper the modern map method is applied to the third- and fifth-order aberration analysis of electromagnetic lenses, focusing on the high order. It is also emphasized that there exist three types of differential algebraic (DA) descriptions for electron optical aberrations. The numerical results of third- and fifth-order aberrations of a given electromagnetic lens computed through the DA technique are shown to be in excellent agreement with those evaluated using electron optical aberration integrals. In conclusion, the DA technique is concise, efficient, and precise for electron optical aberration analysis and the code COSY INFINITY has been proved to be an excellent computer code for such purposes. [Copyright &y& Elsevier]

Previous results have shown that one can have a generalized Transverse Electromagnetic (TEM) plane wave propagating in the u[sub 3] direction in u[sub 1], u[sub 2], u[sub 3] orthogonal curvilinary coordinates. The formal fields are functions of u[sub 1] and u[sub 2] only and have components in both these directions. The medium is inhomogeneous but isotropic, with formal propagation speed (with respect to the u[sub 3] coordinate) a function of only u[sub 3]. In this case the u[sub 3] surfaces can only be planes or spheres. The case of constant φ surfaces for u[sub 3] gave a class of TEM waves propagating in the φ direction in the usual (Ψ, φ, z) cylindrical coordinate system, thereby giving a bending lens to change the direction of propagation of a TEM wave guided by appropriate conductors. In the present paper the formal fields are assumed to have only one component (electric in the u[sub 1] direction, magnetic in the u[sub 2] direction). This removes the aforementioned restriction on the u[sub 3] coordinate surfaces. The formal constitutive parameters μ[sup 1] and ε[sup 1] are inhomogeneous but isotropic, and the real μ is constrained to be μ[sub 0] as before. Specializing the dielectric lens to a body of revolution with the magnetic field in the φ (i.e., u[sub 2]) direction, several examples of such lenses are developed. Two of these examples correspond to well-known circular coaxial and circular conical transmission lines with uniform media. Another two of these examples are nontraditional, involving line sources or foci. [ABSTRACT FROM AUTHOR]

Charged particle beam trajectories in a simple electromagnetic quadrupole-octupole lens are numerically calculated based on analytical expressions for the +potential distribution. Locations of the lens foci in the image space are determined over a wide range of initial conditions. Relationships between the electrostatic and magnetic lens components that provide correction for chromatic aberrations of off-axis beams, which are different from classical beams, are obtained. Phase contours at the lens exit are calculated for beams occupying the major part of the aperture, and conditions for transforming the phase contour with minimal distortions are found. [ABSTRACT FROM AUTHOR]

A recent result showed that guided transverse electromagnetic (TEM) waves of a very general form could be propagated in an inhomogeneous isotropic dielectric medium with permittivity proportional to Psi[sup -2], where Psi is the cylindrical radius in the usual (Psi,phi,z) cylindrical coordinate system. This has the important property that the permeability mu can be taken as mu[sub 0], a constant. Moreover, very general conductor cross sections in (z ,Psi)coordinates can be specified. This allows for the construction of dispersionless bends in high-voltage transmission systems in which the pulse rise time is small compared to transit times across the transmission-line (e.g., coax) cross section. This is important for high-power pulse sources and antennas. The analysis shows that while the permeability can be allowed to be variable, the choice of mu=mu[sub 0] allows one to specify purely dielectric lenses. Thus the generalized form of a TEM plane wave involving inhomogeneous constitutive parameters can be used for generating lens designs based on the scaling. [ABSTRACT FROM AUTHOR]

The electron optical properties of an electrostatic triplet quadrupole lens used as an electron beam transport device were reexamined, both analytically and by computer simulation, in order to derive limits on the choice of the design parameters of the lens. Furthermore, computer simulation of electron trajectories through a single quadrupole lens, and comparison with experimental results obtained by other authors, have led to a graphical relation between the fringing field end correction and the aspect ratio of the lens. [ABSTRACT FROM AUTHOR]

Abstract: A pulsed sextupole electromagnetic lens with suitably controlled time-dependent magnetic field can in principle focus pulsed neutrons at the same focal point over a wide range of wavelength as the lens removes aberrations. However, in fact, it is difficult to focus neutrons over a wide range of wavelength because attenuation of a practical pulsed sextupole electromagnet is faster than an ideal case. We have devised a method of canceling the difference between the practical pulsed sextupole magnetic field and the ideal magnetic field with the use of a permanent sextupole magnet. We performed simulation calculations to investigate the feasibility of this method, and it was shown that focusing wavelength range spread compared with the case using a pulsed magnetic lens only. This result indicates the usefulness of the method. [Copyright &y& Elsevier]

Variable temperature electron beam induced current technique was employed for the profiling of ZnO p-n homojunctions and the extraction of minority electron diffusion length values in the Sb-doped p-type ZnO region. A thermally induced increase for diffusion length of minority electrons was determined to have an activation energy of ∼145 meV. The latter parameter likely represents carrier delocalization energy and determines the increase of the diffusion length due to the reduction in recombination efficiency. [ABSTRACT FROM AUTHOR]

From numerical experiments, a dramatic observation of temporal-coherence gain of the image field is made for the negative-index superlens with a random quasimonochromatic source, even when there is almost no reflection and no frequency filtering effects. A single-parameter theory which can explain the phenomenon quantitatively is constructed based on the physical picture that signals propagating through the negative-index material on different paths have a different retardation time. The theoretical results agree excellently with the numerical ones. [ABSTRACT FROM AUTHOR]

Abstract: We investigate transverse beam temperature effects on the coupling between Two-Stream and Filamentation instabilities for an electron beam passing through a hot plasma with return current. By denoting , the angle between the wave vector and the beam, transverse beam temperature effects are important for larger than a critical angle which can be determined exactly, the resulting effects being a damping of the instabilities. On the other hand, effects are small for . In particular, the absolute maximum growth rate is found for a wave vector in this region and is therefore not damped by transverse beam temperature. [Copyright &y& Elsevier]

Fluidic adaptive lenses with a transformable lens type were demonstrated. By adjusting the fluidic pressure, not only can the lens properties, such as the focal distance and numerical aperture, be tuned dynamically but also different lens types, such as planoconvex, planoconcave, biconvex, biconcave, positive meniscus, and negative meniscus lenses, can be formed. The shortest focal length for a 20 mm aperture adaptive lens is 14.3 mm when the device is transformed into a positive lens, and -6.3 mm when transformed into a negative lens. The maximum resolution of the fluidic lens is better than 40 line pairs/mm. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]