Deflection Yoke Research Articles

High-precision reconstruction of a heat flux boundary via a programmable scanning electron beam controlled by the voltage waveform design method

A scanning electron beam can be used to construct heat flux boundaries (HFBs). However, the long current response time in the deflection coil using a current control method (CCM) cause the deviation of the current waveform, potentially reducing the accuracy of the reconstructed HFB relative to the target HFB. The impact of the current response time on the reconstruction accuracy increases as the field frequency increases, and the accuracy can be reduced from 0.89 to 0.69. To shorten the current response time and improve the reconstruction accuracy, a voltage waveform design method (VWDM) is introduced as a replacement for the CCM. The result indicates that the accuracy of the HFB reconstructed by a scanning electron beam controlled by the VWDM can reach 0.91. Additionally, increasing the maximum output voltage of the power amplifier used to generate the voltage can further improve the reconstruction accuracy of the HFB with the VWDM. This study provides a new approach for the accurate construction of HFBs for rapid thermal processing, additive manufacturing and thermal assessment of hypersonic vehicles.

Novel multicomponent functionalized biopolymers with enhanced thermal and dielectric properties

A new functionalized biopolymer was obtained by adding ethylenediaminetetraacetic acid to chitin and magnetite nanoparticles (Fe3O4). Thermogravimetric analysis was performed, and dielectric properties were examined. The obtained biopolymer showed better thermal stability, as evidenced by a higher onset temperature. The activation energy calculated using imaginary impedance data and Nyquist plots was found to be consistent. Moreover, the dielectric permittivity decreased rapidly with increasing frequency. At high frequencies, there was no dependence of dielectric loss on temperature and frequency. The obtained biopolymer can be used in many applications such as microwave devices, deflection yoke, high-frequency capacitors, sensors, etc.

Nanostructured Rare Earth Nd3+doped Nickel–Zinc–Bismuth Spinel Ferrites: Structural, Electrical and Dielectric Studies

A series of rare earth neodymium (Nd3+) doped Ni–Zn–Bi nanoferrites of composition Ni0.5Zn0.5Bi0.04NdxFe1.96-xO4 (x = 0.002, 0.004, 0.006, 0.008, 0.010) has been synthesized by a citrate precursor technique. Structural, morphological, electrical, and dielectric characterizations have been undertaken. X-ray diffraction pattern confirmed cubic spinel ferrite structure of the prepared nanoferrites with crystallite size in the range of 25–30 nm. From the Hall-Williamson graphs, a tensile strain has been noticed due to an expansion of lattice with an increase in Nd composition. The octahedral and tetrahedral modes of vibrations were confirmed by Fourier Transform Infrared spectroscopy (FTIR) peaks at wavenumber 590 cm−1and 403 cm−1. The D.C. resistivity performance of the nanoferrites was found in the range of 1010 Ω cm calculated from the current-voltage plot. Dielectric studies were undertaken at room temperature in the frequency range from 10 kHz to 10 MHz. The dielectric behaviour of the prepared samples reveals that the real part increases from 4.85 to 13.67 and imaginary values rise from 0.49 to 4.46 at 105 Hz. The dielectric loss tangent value decreases from 0.34 to 0.15 with the change in Nd ion concentration. The AC conductivity rises from 2.18 × 10−6 to 2.39 × 10−5 S/cm at 105 Hz. These lower values of loss tangent in Nd doped Ni–Zn–Bi nanoferrites materials are useful in deflection yoke and high-frequency applications.

Feedforward control of droplet transition in electron beam freeform fabrication based on dual beam spot method

In this paper, a feedforward control method of droplet transition based on dual beam spot in electron beam freeform fabrication is proposed. A deflection coil is used to form two beam spots on the surface of the workpiece. Images containing the prepositive spot are taken, the height information of the workpiece surface is obtained through image processing method, and feedforward control is performed accordingly. The experiment result shows that the proposed method has excellent detection accuracy. It can keep the droplet transition distance and state stable when the height of the surface to be deposited fluctuates, and achieve uniform and stable deposition morphology.

New Approaches to Precise Measurements of Electron Diffraction Patterns

To increase the measurement precision of electron diffraction patterns, a deep upgrade of EMR-102 diffractometer is performed, its operation parameters are studied, and a single-electron detection system with high temporal resolution (up to 60 MHz) and high spatial resolution (several tens of thousands of pixels per 1 A–1) is elaborated. A special software is developed to control the experiment (in particular, using deflection coils and applying synchronous detection of temporal and spatial parameters of each event of electron detector response) and process experimental data. The upgraded diffractometer was used in a series of precise electron diffraction studies, where the accuracy in measuring relative intensities and spatial (angular) resolution were much better than in similar experiments described in the literature.

A Novel Micro-Multifocus X-Ray Source Based on Electron Beam Scanning for Multi-View Stationary Micro Computed Tomography

We developed a new prototype micro-multifocus X-ray source based on electron beam scanning (MMFEBS) for multi-view stationary Micro Computed Tomography (multi-view stationary Micro-CT). This micro-multifocus X-ray source includes an electron gun, electron beam deflection coils, a dynamic condensor, a flat panel transmission target and dynamic vacuum system. The electron beam is controlled by the deflection coils and sweeps back and forth on the flat panel transmission target. It hits a series of accurately-defined positions on the target, resulting in two-dimensional X-ray multi-focus array. A dynamic condensor is utilized to overcome the electron beam defocusing caused by the deflection. It guarantees the same high spatial resolution (better than $4~\mu \text{m}$ ) at any deflection angle. The MMFEBS, together with a rotational stage and a flat panel detector, produces a multi-view stationary Micro-CT which can obtain multi-view X-ray projection data for CT images in static condition. Micron resolution CT images obtained in our experiments showed that the MMFEBS has high resolution and good repeatability.

6-9 新コマ収差補正方式偏向ヨークの開発

6-9 新コマ収差補正方式偏向ヨークの開発

Signal emitted from plasma during electron-beam welding with deflection oscillations of the beam

The oscillations of a signal, collected by a ring electrode with +50V potential, situated in the plasma over the welding zone during electron beam welding (EBW) with local beam deflection oscillations were studied. Samples of chrome-molybdenum steel were processed. The frequencies of the beam oscillations varied between 150 and 1400Hz and their trajectories were the simplest: along and across the joint. The position of the beam focus was changed. Fluctuations of the emitted plasma current by coherent accumulation of the signal amplitudes were analysed and the probability for instability excitations in the keyhole was estimated. This method allows the study of the random instability processes at the interaction of the beam with the keyhole wall and bottom. A time shift between the maxima of the function derived from the coherent accumulation and the extremes of the deflection coil current was found. This shift depends on the beam focus position. In addition, at longitudinal beam oscillations, and at variations of the focus position a difference of the extreme values of the studied signal was observed. At the lowest values of the current of the focusing electromagnetic lens, the differences between the maxima of the probabilities for excitation of the plasma signal oscillations in the moments at beam bombardment on the front and trailing walls of the keyhole in the molten pool were about 30%, while the beam over-focusing decreased these differences. For beams situated at the central part of the keyhole, the collected signal was minimal. From the observations of spikes in the weld root, at EBW with deflection oscillations, it was concluded that self-focusing of the beam in the bottom part of the keyhole in the cases of the most focusing positions was occurring.

Transport properties of microwave sintered pure and glass added MgCuZn ferrites

Abstract A series of pure stoichiometric and 1 wt% lead borosilicate (PBS) glass added MgCuZn ferrite with the general formula Mg 0.5 Cu x Zn 0.5− x Fe 2 O 4 with x = 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3 were synthesized by microwave sintering technique. Single phase spinel structure is exhibited by the XRD patterns of these ferrites. DC and AC conductivity were investigated as a function of composition, temperature and frequency. DC conductivities were also estimated using the impedance spectroscopy analysis of Cole–Cole plots. The DC conductivities thus obtained are in good agreement with the experimental results. All the investigated samples exhibited two regions of conductivity one in the low temperature and the second in the high temperature region. It is observed that PBS glass added samples have lower conductivities than pure samples. Due to their lower conductivities and sintering temperatures the 1 wt% PBS glass added samples are suitable for multilayer chip inductor (MLCI) and high definition TV deflection yoke material application.

Digital Design and Numerical Control Processing of Deflection Yoke Based on Top-Down

In this paper, it introduces the design processing and implementation method of digital technology based on Top-down, analysis the advantages of the method using Top-down in the product design. To deflection yoke for example, completed digital design and assembly of the deflection yoke based on Top-down, and completed the NC processing by using numerical control machine tool

Structure Analysis of Electron Gun Deflection Coil Based on ProE and ANSYS

Through the example of the electron gun deflection coil, this paper implements the structure modeling with ProE and makes the finite element analysis with ANSYS .The structure analysis is performed by the combination of the advantages of two softwares. The reasonableness of the design is verified. This method helps to optimize the structural design of the coil. The production of precision of the coil was improved, and coil size can effectively control and reduce material waste.

Regression analysis for deflection magnetic field parameters measured by the dual-coil method

In this study, the magnetic field-parameters of a typical saddle-shaped deflection yoke were measured using the dual-coil method developed by the group. The measurement data was processed and analyzed using two methods: 2-variable regression analysis method and 3-variable regression analysis method. The two results were compared with the analytically calculated results, which was used as the reference. It was shown that the data collection range has large impact to the results of H 2, H 4, and the further away from the central axis the probe is placed, the larger the error is. The errors of H 2 and H 4 are smaller using the 3-variable regression analysis method as compared with the ones using 2-variable regression method. The 3-variable regression analysis method uses H 6 in the process of calculating H 2 and H 4, which is coincident with the definition of them in the formula of H y = H 0 + H 2 X 2 + H 4 X 4 + H 6 X 6 +⋯.

Image improvement with modified scanning waves and noise reduction in a scanning electron microscope

In order to acquire a high-resolution image in a scanning electron microscope (SEM), a well-modulated current profile on the deflection coil must be generated by a scan waveform, and a properly selected scan waveform can eliminate the distortion of the image. In this work, various adjustments to the scan waveform, including the frequency, slope, and flatness, were analyzed. A new scan waveform using sinusoidally varying voltages was found to reduce distortion, particularly at the outer range image. The SEM image was also improved by reducing noise from the driver circuit and separating electrical grounding of the scanning coils.

Energy Density Distribution and Temperature Closed-Loop Control in Electron Beam Processing

Various electron beam (EB) processing methods such as EB brazing, surface modification, heat treatment, etching, evaporation coating and quick manufacture, etc. require that the energy distribution and processing temperature be controlled. In this study, the energy distribution control was realized by EB scanning trajectory pattern control, and the temperature control was realized by the combined use of fuzzy logic and PID control. These were integrated into one system. To obtain large deflection angle of EB, an external deflection coil was used. The scanning trajectory pattern was the synthesization of deflections of EB in X and Y directions, and each of the deflections was controlled by an analog. Because of high energy density of the EB, and consequently high sensitivity of weldment temperature to the beam current, closed-loop control of processing temperature is indispensable, which was realized in this paper. Satisfactory transient and steady-state specifications were obtained. The brazing of a specially designed specimen verified the effectiveness of the method.

저온소결 온도변화에 따른 Ni-Zn-Cu 페라이트의 자기적 특성 연구

We have synthesized the low temperature sintered of Ni-Zn-Cu ferrite with nonstoichiometric composition a little deficient in from . For low loss and acceleration of grain growth and was added from 0.25 mol% to 1.0 mol%. The mixture of the law materials was calcinated and milled. The compacts of toroidal type were sintered at different temperature for 2 hours in air followed by an air cooling. Then, effects of composition and sintering temperatures on the physical properties such as density, resistivity, magnetic induction, coercive force, initial permeability, and quality factor of the Ni-Zn-Cu ferrite were investigated. The density of the Ni-Zn-Cu ferrite was , resistivity revealed . The magnetic properties obtained from the aforementioned Ni-Zn-Cu ferrite specimens were 1,300 gauss for the maximum induction, 4.5 oersted for the coercive force, 275 for the initial permeability, and 83 for the quality factor. The physical properties indicated that the specimens could be utilized as the core of high frequency range (involved microwave range) communication and deflection yoke of T.V.

A classifier learning system using a coevolution method for deflection yoke misconvergence pattern classification problem

Deflection yoke (DY) is one of the core components of a cathode ray tube (CRT) in a computer monitor or a television that determines the image quality. Once a DY anomaly is found from beam patterns on a display in the production line of CRTs, the remedy process should be performed through three steps: identifying misconvergence types from the anomalous display pattern, adjusting manufacturing process parameters, and fine tuning. This study focuses on discovering a classifier for the identification of DY misconvergence patterns by applying a coevolutionary classification method. The DY misconvergence classification problems may be decomposed into two subproblems, which are feature selection and classifier adaptation. A coevolutionary classification method is designed by coordinating the two subproblems, whose performances are affected by each other. The proposed method establishes a group of partial sub-regions, defined by regional feature set, and then fits a finite number of classifiers to the data pattern by using a genetic algorithm in every sub-region. A cycle of the cooperation loop is completed by evolving the sub-regions based on the evaluation results of the fitted classifiers located in the corresponding sub-regions. The classifier system has been tested with real-field data acquired from the production line of a computer monitor manufacturer in Korea, showing superior performance to other methods such as k-nearest neighbors, decision trees, and neural networks.

Fabrication of gradient material by electron beam smelting based on scanning track control

A new electron beam (EB) control system was developed in a general vacuum EB machine by equipping it with an industrial control computer, programmable logic control (PLC), deflection coil, data acquisition card, power amplifier, etc. In this control system, the scanning track and energy distribution of the EB could be edited off-line, adjusted in real-time, and controlled on-line. Ti-Mo gradient material (GM) with high temperature resistance was fabricated using electron beam smelting (EBS) control. The smelting pro cesses include three steps such as preheating, smelting, and homogenizing. The results show that GM prepared by using smelting technology has fine appearance, and has good integrated interface with Ti alloy. The Mo and Ti elements are gradual diversification in the interface of the gradient material. The microstructure near the Ti alloy base metal is α+β basket-waver grain, and the microstructure near GM is single phase of β solid solution.

A classification method using a hybrid genetic algorithm combined with an adaptive procedure for the pool of ellipsoids

This paper presents a hybrid classification method that utilizes genetic algorithms (GAs) and adaptive operations of ellipsoidal regions for multidimensional pattern classification problems with continuous features. The classification method fits a finite number of the ellipsoidal regions to data pattern by using hybrid GAs, the combination of local improvement procedures and GAs. The local improvement method adaptively expands, rotates, shrinks, and/or moves the ellipsoids while each ellipsoid is separately handled with a fitness value assigned during the GA operations. A set of significant features for the ellipsoids are automatically determined in the hybrid GA procedure by introducing "don't care" bits to encode the chromosomes. The performance of the method is evaluated on well-known data sets and a real field classification problem originated from a deflection yoke production line. The evaluation results show that the proposed method can exert superior performance to other classification methods such as k nearest neighbor, decision trees, or neural networks.

Ni-Zn Ferrite의 조성성분 및 소결온도에 따른 물리적 특성의 실험적 연구

기본조성 <TEX>$(Ni_{0.35}Cu_{0.2}Zn_{0.45})_{1.02}(Fe_2O_3)_{0.98}$</TEX>과 NiO 비율을 증가시키고 ZnO을 감소시킨 또 다른 기본조성 <TEX>$(Ni_{0.4}Cu_{0.2}Zn_{0.4})_{1.02}(Fe_2O_3)_{0.98}$</TEX>에 grain boundary의 높은 저항층을 형성하고 flux로서 사용하기 위해서 0.1 mol% <TEX>$CaCO_3$</TEX>와 입자의 성장을 촉진시켜 낮은 손실, 높은 투자율을 얻기 위한 목적으로 <TEX>$V_2O_5$</TEX>를 0.03mo1% 첨가하였다. 이들 원료들을 혼합한 후 <TEX>$600^{\circ}C$</TEX>에서 2시간 동안 가소시킨 분말을 toroid 시편으로 만들어 소결온도 <TEX>$1,050^{\circ}C,\;1,070^{\circ}C,\;1,100^{\circ}C$</TEX>에서 각각 2시간 동안 공기 중에서 소결하였다. 각 시편들에 대한 밀도는 <TEX>$4.90{\sim}5.10g/cm^3$</TEX>으로 나타났고, 각 시편들의 고유저항은 <TEX>$10^8{\sim}10^{12}{\Omega}-cm$</TEX>으로 측정되었으며, 결정립의 크기는 대략 <TEX>$3.0{\sim}8.0{\mu}m$</TEX>이었다. 시편들의 자기유도 특성 값이 대부분 우수하게 나타났으며, 그 중에서도 기본조성 <TEX>$(Ni_{0.4}Cu_{0.2}Zn_{0.4})_{1.02}(Fe_2O_3)_{0.98}$</TEX>에 <TEX>$CaCO_3$</TEX>와 <TEX>$V_2O_5$</TEX>를 첨가하고 <TEX>$1,070^{\circ}C$</TEX>에서 소결한 시편의 특성 값이 잔류자기유도 1,660 G, 최대자기유도 4,000 G로 약간 더 우수하게 측정되었으며, 각각 시편들의 보자력은 <TEX>$0.15{\sim}0.25\;Oe$</TEX>로 전형적인 연자성 재료의 범위로 나타났다. 초투자율, 손실계수, 및 큐리온도는 각각 <TEX>$2,948{\sim}2,997,\;171{\sim}208,\;191{\sim}202^{\circ}C$</TEX>로 나타나 Ni-Zn ferrite에서 측정되는 값들과 대동소이했다. 물리적인 특성값(고유저항, 자기유도, 초투자율, 손실계수, 큐리온도 등)으로 미루어보아 각종 microwave 통신기기 core 및 고 투자율 deflection yoke core 등으로 사용이 가능하다. The basic composition of Ni-Zn ferrite was <TEX>$(Ni_{0.35}Cu_{0.2}Zn_{0.45})_{1.02}(Fe_2O_3)_{0.98}$</TEX> (group A) and <TEX>$(Ni_{0.4}Cu_{0.2}Zn_{0.4})_{1.02}(Fe_2O_3)_{0.98}$</TEX>(group B) with additional 0.1 mol% <TEX>$CaCO_3$</TEX> and 0.03 mol% <TEX>$V_2O_5$</TEX>. For high permeability and acceleration of grain growth, <TEX>$CaCO_3$</TEX> and <TEX>$V_2O_5$</TEX> was added. The mixture of the law materials was calcinated at <TEX>$600^{\circ}C$</TEX> for 2 hours and then milled. The compacts of toroidal type were sintered at different temperature (<TEX>$1,050^{\circ}C,\;1,070^{\circ}C,\;1,100^{\circ}C$</TEX>) for 2 hours in air followed by an air cooling. Then, effects of various composition and sintering temperatures on the microstructure and physical properties such as density, resistivity, magnetic induction, coercive force, initial permeability, quality factor, and curie temperature of the Ni-Zn ferrite were investigated. The density of the Ni-Zn ferrite was <TEX>$4.90{\sim}5.10g/cm^3$</TEX>, resistivity revealed <TEX>$10^8{\sim}10^{12}{\Omega}-cm$</TEX>. The average grain size increased with the increase of sintering temperatures. The magnetic properties obtained from the aforementioned Ni-Zn ferrite specimens were 4,000 gauss for the maximum induction, 0.25 oersted for the coercive force, 2,997 for the initial permeability, 208 for the quality factor, and <TEX>$202^{\circ}C$</TEX> for the curie temperature. The physical properties indicated that the specimens could be utilized as the core of microwave communication and high permeability deflection yoke of high permeability.

New method to correct eddy current in magnetic focusing-deflection system

Analysis and new structure is introduced to correct eddy current in electron beam focusing-deflection system. Maximum errors caused by eddy current are computed by changing permeability of the conductive materials at time t 0 ( t 0 = 0, μ = 0) and t ∞ ( t 0 = ∞, μ = μ r) with the aid of Munro’s software. The new double ferrite structure includes outer- and inner-layer ferrite rings which are spaced by ceramic spacer uniformly and staggered each other in radial direction. Basic principle for eddy current correction in this paper is that ferrite materials prevent the flow of magnetic flux from the deflection coil to the polepiece without perturbing the lens field. Magnetic flux of various lens structures and magnetic scalar equipotential lines of various deflectors illustrate the principle. Correction and performance versus the values of the gap (G) and the space (S) between the ferrite rings are considered. The new double ferrite structure not only corrects the eddy current, but also increases the sensitivity of the deflection without decreasing the performance.