摘要:

AbstractThis paper presents a calculation of the third‐order nonlinear susceptibility for the frequency upconversion of 10‐μm atmospheric window to the visible band. The following cases are compared.Two‐photon resonance 1 at 6 d2D3/2, and 2 at 6 d2D5/2of cesium to generate difference frequency. 3 Two‐photon resonance at 7 s2S1/2of cesium to generate sum frequency. 4 Two‐photon resonance at 3 d2D5/2of sodium to generate sum frequency. Density matrix is used in the calculation, and the spinorbit coupling and the Doppler effect are considered. The major results are the following. In 1, a large nonlinear susceptibility and large number density is obtained at relatively low temperature. The nonlinear susceptibility has the maximum at the wavelength of 12.1 μm. In 2, a large nonlinear susceptibility and large number density are obtained at relatively low temperature. The nonlinear susceptibility increases with the increase of infrared wavelength. In 3, a system free from polarization property can be constructed, but the temperature must be raised by more than 100°C, compared with the forementioned two cases. In 4 the largest nonlinear susceptibility is obtained for the wavelength of 9.1 μm. However, the temperature must be raised by several hundreds degree compared with the cas

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe pattern recognition of a spectral characteristic which is the same method as the latter recognition, is one of the most widely used in remotely sensed multispectral image processing. There are many pixels in remotely sensed image data in which multiple categories are mixed within an instantaneous field of view. This paper points out that a conventional category classification in which the generalized distance of a feature space is used as the evaluation standard of the similarity is not necessarily suitable for the contents of pixels in remotely sensed image data. Also, it is more logical to use a method based on the calculation of the areaoccupation rate (the mixture ratio) of each category. From the viewpoint of the composition and decomposition of the categories, the generalized inverse matrices, least‐square, and quadratic programming were reexamined, and they are compared with conventional methods by using numerical examples. The results confirm the usefulness of the categorydecomposition method and problems of the conventional category‐classification methods including the maximum‐likelihood method (i.e., misclassification of pixels containing multiple categories). As a conclusion, if a more accurate calculation of the mixture ratio becomes available by a further development of the method, a higher order of information than that by a conventional categoryclassification processing applied to the image data on the earth surface will be obtained; it will even be possible to exceed the limit of the space‐resolution of a remote

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractBy taking a forward‐type converter, the control characteristics of a switching regulator controlled by a half‐wave magnetic amplifier were analyzed using the models of the dc‐magnetizing characteristic and the reverse recovery of the diode so that the relationship between the switching frequency and the controllable region were described quantitatively. The results show that the dead angle in a magnetic amplifier can represent a function of the dynamic resistance of the core and the magnetic permeability of the core, and that this in a high‐frequency operation cannot be determined by the rectangularity alone. When the magnetic amplifier is used for a pulse‐width modulator of a converter, the reverse recovery of rectifier diodes considerably affects the control characteristic of the magnetic amplifier, limiting its maximum on‐time at the frequency above a few hundred kilohertz. By using the model of the dc‐magnetizing characteristic, the power loss of the core is represented by a function of the parameters of the core and switching frequency so that the iron loss of the magnetic amplifier is expressed q

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractRecently, crystal oscillators are used increasingly with the advances of electronic components. Particularly, the adjustmentfree crystal oscillators with only a few circuit elements are used widely since they are suited for IC's. Hence, stabilization of their frequency is very important. In this paper, the simplest emitter follower type crystal oscillator made of a transistor, a quartz crystal, a capacitor, and three resistors is studied in terms of its frequency stability. From the calculations and experiments, the following results have been obtained.The oscillation frequency is more stable against the change of an external capacitance if larger values are chosen for the collector capacitanceCC, the grounded base current gain α, and the α cutoff frequencyfα. Against the change of the power supply voltage, the optimum value offαcan be determined afterCCis selected from the forementioned condition. The oscillation frequency deviation is smaller for a larger equivalent inductanceL1regardless of theQvalue of the crystal. Based on these results, it is found that the improvement is more than sixfold against the variation of the power supply voltage, and more than elevenfold against that of the circuit capacita

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA three‐dimensional photoresist shape simulator has been developed for the submicron process. Using this simulator, it is possible to analyze and optimize the photoresist process using an arbitrary projector, photoresist, and developer. In this technique, considering the man‐machine interface, the three‐dimensional shape of the photoresist can be shown in a colorgraphic VDT and plotter. Comparing the result of the threedimensional simulation using the contact hole pattern with that of the two‐dimensional simulation, a discrepancy occurs in the dimension less than 1 μm between the two techniques, and it has been found that threedimensional simulation is necessary when the width and depth of the pattern are in the same order. Using the three‐dimensional simulation, a resolution of 0.5 μm cannot be achieved when the wavelength of the light source is 435.8 μm, the numerical aperture of the projection lens N.A. is 0.28, and the coherency s̀ is 0.7. However, such a resolution can be achieved by using the wavelength of the light source of 435.8 nm, N.A. of 0.42,

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe dome antenna has been proposed for high‐speed scanning of the main beam of the antenna in a wide‐angle range. For the design of the dome antenna, an analysis for the electromagnetic field in the concave side of the conducting sphere is indispensable. In connection with this problem, several studies have been reported on the cylindrical concave surface. However, no report is available to date on the electromagnetic field for a practical concave conducting sphere for which both the source and the observation points are removed from the boundary. This paper describes the results of analysis for this type of electromagnetic problems. First, the integral expressions for the electric field are obtained in the form of a sum of Whispering Gallery (WG) modes and a continuous spectrum. In the derivation of the field expression, spurious diffracted waves are included due to a hypothetical conical absorber, and these waves are eliminated. A scheme is implemented in which the pole contribution of the wavenumbe in the zenith angle θ so that the numerical difficulty is removed. Actual numerical calculations have been performed and the validity and range of applicability have been studied for the expression. It is found that the expression derived in this paper provides a valid field solution for the case wherekα (kis the wavenumber and α is the sphere radius) is sufficiently larger than unity and is an integral multiple

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe applicability of the Hi‐BiCMOS (High Performance Bipolar CMOS) technology to the 32‐bit execution unit has been researched to improve the function and speed of such processors as minicomputers CPUs. The HiBiCMOS technology enables MOS devices with performance comparable to pure CMOS LSIs and bipolar devices with performance comparable to pure bipolar LSIs to be combined on the same substrate. Device integrations comparable to CMOS LSIs have been achieved by the utilization of macrocells composed mainly of MOS circuits. Attempts have been made to speed‐up the macrocells by adding Hi‐BiCMOS circuits.In this paper, the feedback‐type smallamplitude precharge circuit is proposed and fabricated. This circuit affords precise bus voltage. Also, the carry propagation circuit that uses the bipolar sense amplifier to achieve the machine cycle of 25 ns is proposed. Consequently it is confirmed that the precharge circuit operates two times faster and the carry propagation circuit 3.3 times faster than pure CMOS circuits. Thus, one of the promising candidates for the ultrahigh‐speed one‐chip proces

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper calculates the reflection and transmission coefficient at a discontinuity in rectangular dielectric waveguides. At the discontinuity, waveguides of two different sizes are connected concentrically. Generally speaking, radiation modes generated at the discontinuity in open waveguides make analysis difficult.Here, double Fourier transformation is applied to field distributions at the discontinuity so that a guided and radiation mode can be treated identically. Since the reflection and transmission coefficient can not be obtained immediately by solving the boundary condition equations at the discontinuity, a ratio of electric and magnetic field intensities of the radiation mode is introduced and converged to constant by an iterative approximation. This approximation formula is derived from an orthogonal relation between the guided and radiation mode. If this ratio is converged to a steady value, the reflection and transmission coefficients are converged simultaneously. In addition, the reflection, transmission and radiation power at the discontinuity are calculated numerically. These results are compared with those obtained from the mode matching method which is useful when the discontinuity is so small.The theory in this paper is advantageous in analyzing the discontinuity at a waveguide junction. The analytical method is applicable to an off‐axial junction of the waveguide and the analysis of a rectangular dielectric rod antenn

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe surface‐emitting laser can be fabricated monolithically via planar technology and mass‐produced for applications to laser discs and optical IC's for optical communication. However, the transverse mode control in the surface‐emitting laser, which is important to laser oscillation, has not been well studied. This paper discusses the transverse mode control for the surfaceemitting laser and clarifies the shape of the single transverse mode in the structure. As a result of the calculation for a laser wavelength of 1.3 μm, if the composition of the waveguide core (the carrier‐confining layer) is λ = 0.93 μm in a structure where a waveguide is built in the cavity, the waveguide radius must be less than 2 μm. For a structure where only the active layer is embedded, the radius of the reflector must be 3 to 4 μm or the radius of the active region must be 5 to 7 μm when the reflector radius is 10 μm. Therefore, even in the surface‐emitting laser, the transverse mode control can be achieved r

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractIn the growth of KDP single crystals by the temperature decrease method, the dimensions of equipment for the growth of the crystal whose dimensions are desired for type I and type II phase matching of SHG are discussed, where the (001) plate and (101) plate are used as seed crystals, respectively. It is shown that the equipment has the smallest dimensions in the growth of the crystals for type II with the seeds of the (101) plate. Then the large crystals are grown with the seeds of the (101) plate and their optical characteristics are described.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY