摘要:

AbstractNumerical analysis of the scattering of a beam wave caused by pits which are assumed to be absolute conductors is carried out in order to obtain the optimum shape of pits and pregrooves and achieve high density on an optical disk. For analysis, the boundary element method (BEM) is used because it is adaptable to any shape of pits and pregrooves and any type of incident beam. For rectangular or trapezoidal concave and convex pits, scattered fields and induced currents are calculated as functions of the angle of the pit wall and track pitch, and comparison between the two is made. In the case of convex pits, it is found that the minimum track pitch without crosstalk for E‐wave and H‐wave are 2wand 1.8w(w: the spot size of the incident beam), respectively. As the pit shape is changed from rectangular to trapezoidal, the intensity change of the main lobe with or without the pit is small. Finally, the current density on the disk, which is induced by scattering, is calcula

ISSN:8756-663X    

DOI:10.1002/ecjb.4420721201

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

年代:1989

数据来源: WILEY

摘要:

AbstractA geometrical law describing the reflection of wavefronts and wave normals of non‐spherical waves at interfaces is presented. Generally speaking, the angle of incidence and the angle of reflection are different, and the difference is a function of the configuration of the wavefront of the incident wave. With regard to plane wave reflection, the present results are in agreement with conventional law

ISSN:8756-663X    

DOI:10.1002/ecjb.4420721202

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

年代:1989

数据来源: WILEY

摘要:

AbstractConsider a Cerenkov laser, using for the slow‐wave structure a dielectric waveguide whose substrate consists in a nonlinear dielectric presenting the self‐focusing effect. The characteristics of the Cerenkov laser specified in the foregoing are investigated theoretically for the two‐dimensional model which takes into account the field distribution in the transverse direction.First, the dispersion relations are considered for the electromagnetic wave modes (TM waves) propagated along a two‐dimensional nonlinear dielectric waveguide. Then the dispersion relations are discussed for the coupled electromagnetic fields in the Cerenkov laser using the nonlinear dielectric waveguide. Finally, the spatial growth rate of the growing wave obtained from the dispersion relation for the coupled fields derived in the foregoing is investigated numerically in detail. From the forementioned discussion, it is found that the spatial growth rate for the Cerenkov laser treated in this paper is improved compared to the Cerenkov laser for which the slow‐wave structure is composed of linear dielect

ISSN:8756-663X    

DOI:10.1002/ecjb.4420721203

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe conditions have been investigated for drawing the SiO2core/F‐SiO2cladding single‐mode optical fiber which is expected to have the lowest optical loss among the silica optical fibers. In this type of optical fiber, the softening temperature of the core is higher than that of the cladding, and the softening temperature distribution is different from that of the GeO2‐SiO2core/SiO2cladding‐type optical fibers. In this study, the residual stress in the fiber during drawing was investigated theoretically and experimentally, considering the softening temperature difference between the core and cladding. The following results were obtained. In the SiO2core single‐mode optical fiber, the tensile stress remains in the core where it is proportional to the drawing tension and inversely proportional to the area of the cross section. The residual stress influences the refractive index of the core and the cut‐off wavelength, but degrades the propagation loss characteristic. Finally, this paper will show that: (1) this optical fiber belongs to the F‐SiO2core/F‐SiO2cladding type from the viewpoint of the material, and (2) the depressed‐type structure is

ISSN:8756-663X    

DOI:10.1002/ecjb.4420721204

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

年代:1989

数据来源: WILEY

摘要:

AbstractFor an application for electrophotographic photoreceptors, a‐Si1‐xCx:H film was prepared by a plasma CVD method with C2H4or CH4as a carbon source, and the dependence of water wettability on the source gas and carbon concentration as well as the dependence of the contact angle with water on the corona exposure has been examined. Surface reactants formed after the corona exposure have also been examined. As a result, it was found that the wettability of the a‐Si1‐xCx:H film decreases with the carbon concentration independent of the source gas. However, corona exposure for one hour increased the water wettability. This trend was found to be independent of the carbon concentration in the film. As a result of the infrared absorption spectrum, this was attributed to the formation of Si‐Oxbond (x= 1.7 ‐ 2.0) by coro

ISSN:8756-663X    

DOI:10.1002/ecjb.4420721205

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe authors developed a dual‐frequency (40/100 GHz) SIS receiver with SIS quasi‐particle tunneling junction element as the mixer, for use in the millimeter‐wave array at Nobeyama Radio Observatory, National Astronomical Observatory. The SIS element used is an array composed of four series‐connected Nb/Al‐AlOx/Nb junctions. The receiver is refrigerated to 4.3 K by a closed‐cycle He refrigerator. The receiver realized a very low receiver noise temperature for a wideband, such as 50 to 80 K for 43 to 49 GHz, and 60 to 100 K for 86 to 115 GHz. A wide dynamic range is also realized. At 40 Ghz, the saturation noise temperature is 2000 to 3000 K, compared with the wideband noise. These results indicate that the SIS array element can effectively improve the mixer saturation level without degrading the receiver

ISSN:8756-663X    

DOI:10.1002/ecjb.4420721206

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

年代:1989

数据来源: WILEY

摘要:

AbstractAlthough a number of realization circuits for second‐generation current conveyors (CCII) and their applications to active RC networks have been reported, the bandwidth of CCII itself is not sufficient. It is pointed out that one of the causes of degradation of the RF characteristics of the CCII using the complementary transistors is the effect of signal current flow through the collector capacitanceCc. A method is described also for broadband operations by compensating this effect actively. In practice, a transistor with the gain bandwidth productfTof 100 MHz is used for construction of a positive‐type CCII. The voltage transfer factor and the impedance looking into theXterminal have improved with or without compensation while the current transfer factor has improved with compensation so that those are almost ideal characteristics within the measurement up to 10 MHz. The magnitudes of the impedances looking into theYandZterminals decreased beyond about 100 kHz due to the effect of the stray capacitance of each terminal andfT. However, there is improvement as the magnitude is larger by an order than the uncompensated case. As an application, the compensated positive‐type CCII is used for construction of a biquad low‐pass filter with the pole frequency of about 3 MHz. The operation was satis

ISSN:8756-663X    

DOI:10.1002/ecjb.4420721207

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

年代:1989

数据来源: WILEY

摘要:

AbstractTo understand the electric breakdown characteristic of anodized tantalum pentoxide (Ta2O5) films, the electroluminescence phenomenon was investigated in the electric field ranging from low field to the breakdown field. Since the luminescence is weak, it was detected by using a photomultiplier tube and a lock‐in amplifier.The luminescence was independent of temperature but was strongly dependent on the applied voltage. When the electric field was slightly lower than the breakdown field, the luminescence due to the carrier injection based on the Schottky effect was observed. When the electric field was close to the breakdown voltage, luminescence due to the electron avalanche was observed, where the luminescent spectrum had a peak at 600 nm.These observations indicated that the electric breakdown is related to the electron avalanch

ISSN:8756-663X    

DOI:10.1002/ecjb.4420721208

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

年代:1989

数据来源: WILEY

摘要:

AbstractTo realize functions which cannot be achieved by conventional integrated circuits composed of bulk transistors (bulk‐Tr), part of an integrated circuit was formed by laser‐recrystallized SOI transistors (SOI‐Tr) using the lateral seeding process. The uniqueness of this structure is that the bulk‐Tr's and SOI‐Tr's are formed in the same plane. To realize this planar structure, the necessary basic technology was developed and bulk‐Tr's and SOI‐Tr's were formed in the same plane to test the structure. The characteristics of the transistors were compatible to those of transistors formed by conventional MOS processes. For the application of this structure to integrated circuits, a solid‐state image sensor was fabricated where the driver circuits were formed by the bulk‐Tr's and the read‐out of the picture elements was carried out by using the SOI‐Tr's. As a result, a high‐quality image was obtained and the smear noise caused by photoleakage

ISSN:8756-663X    

DOI:10.1002/ecjb.4420721209

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe characteristics of low‐frequency noise in a dc‐SQUID are discussed from both the simulation analysis by numerical calculations and the measured results. The acbias method conceived based on the simulation results is used for evaluation of the low‐frequency noise in a SQUID after it is separated into: (1) the component due to asymmetric fluctuation of the two junction parameters; and (2) the variation of the magnetic flux linking with the SQUID ring. It is found that for the former, the magnitude is strongly dependent on the inductance value and the value is rather large even in the SQUID with Josephson elements of the type other than the tunnel junctions. With respect to the latter, the magnitude is on the same order as the parameter fluctuation noise and is caused mainly by the trapped magnetic

ISSN:8756-663X    

DOI:10.1002/ecjb.4420721210

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

年代:1989

数据来源: WILEY