bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical Analysis of Oxygen-Excess Defects in SiO2 Thin Film by Molecular Orbital Method
Authors: Takeshi Kanashima Takeshi Kanashima , Masanori Okuyama Masanori Okuyama , Yoshihiro Hamakawa Yoshihiro Hamakawa 
Published: October 2002

Energy states of oxygen-excess defects in SiO2 have been studied by theoretical analyses using molecular orbital calculation and discussed on the basis of comparison with photoluminescence of SiO2 thin films. Theoretical analyses have been carried out using both the semi-empirical and ab-initio methods, and have shown that the transition energy from the excited singlet state to the ground state is 2.32 eV with the STO-3G basis set and 2.40 eV with the 3-21G basis set, which are very close to the 2.4 eV photoluminescence peak measured in the photo induced chemical vapor deposition SiO2 thin film. This analysis and the effects of annealing in O2 and N2 atmospheres suggest that origin of the photoluminescence peak at 2.4 eV is oxygen-excess defect.
Investigation of Discharge Phenomena in a Cell of Color Plasma Display Panel I. One-Dimensional Model and Numerical Method
Authors: Takahashi Kazuo , Hashiguchi Seishiro , Murakami Yukio , Takei Makoto , Itoh Kazuhiro , Tachibana Kunihide , Sakai Tetsuo 
Published: October 2002

A numerical simulation method using a one-dimensional fluid model under the local field approximation is presented in order to understand pulsed-dc discharge in He–Xe gas mixture in a cell of a full-color plasma display panel. Spatiotemporal behaviors of the electric field and number densities of twelve independent particles, including electrons and four kinds of ions, were calculated self-consistently at a gas pressure of 200 Torr (27 kPa) and an electrode distance of 0.02 cm. The imprisonment of 147-nm-resonance radiation, the excitation source of phosphors, was also taken into account. Calculated results of the discharge current and voltage are consistent with those of experiment. The waveform of 147-nm-resonance radiation agreed well with experiment, although that of the discharge current showed some difference, probably due to the local field approximation.
High-Rate and Smooth Surface Etching of Al 2O 3-TiC Employing Inductively Coupled Plasma (ICP)
Authors: Fukushima Nobuto , Katai Hiroaki , Wada Toshiaki , Horiike Yasuhiro 
Published: October 2002

High-rate and smooth surface etching of Al2O3-TiC, which is widely used as a slider material for magnetic recording heads, has been developed employing inductively coupled plasma (ICP). The etching rate of 200 nm/min was obtained with Cl2/BCl3 mixture. However the etched morphology exhibited roughness around 40 nm Ra (arithmetic average deviation from center line) because of different etching rates for Al2O3 and TiC grains in the substrate. The addition of Ar to the Cl2/BCl3 improved both the etching rate and roughness of the etched surface considerably. As a result the high etching rate of more than 350 nm/min, which is more than ten times that of conventional Ar+ ion etching, and relatively smooth surface roughness around 20 nm Ra were achieved with Ar/Cl2/BCl3 mixture using 1.2 kW RF power and -500 V V
dc.
Hybrid Finite-Element Analysis of Leaky Surface Acoustic Waves in Periodic Waveguides
Authors: Koji Hasegawa Koji Hasegawa , Masanori Koshiba Masanori Koshiba 
Published: October 2002

A numerical approach based on the hybrid finite-element method (HFEM) is developed for the analysis of leaky surface acoustic wave (LSAW) propagation along periodic waveguides. Only a region corresponding to one period of the waveguide is discretized, and the dispersion relation between complex propagation constants and frequencies around a stop band and the standing-wave distributions at these frequencies are calculated. Using the hybrid variational principle, the region to which HFEM is applied is divided into elements with suitable interpolation functions; the inhomogeneous region including electrodes is divided into conventional quadratic elements of the serendipity class, and the remaining homogeneous substrate region is replaced with a hybrid element with specialized interpolation functions which are derived from modal expansions and satisfy the radiation condition of LSAWs. In this method, all the effects of piezoelectric perturbation, mechanical perturbation, energy storage due to nonradiated bulk waves, and radiation loss of LSAWs are automatically taken into account. Using this method, aluminum strip gratings on an Al/ST-X quartz or a 36° Y–X LiTaO3 substrate are analyzed, and the validity of this method is confirmed.
5 GHz Range Low-Loss Wide Band Surface Acoustic Wave Filters Using Electrode Thickness Difference Type Unidirectional Transducers
Authors: Hiroyuki Odagawa Hiroyuki Odagawa , Toshiyasu Meguro Toshiyasu Meguro , Kazuhiko Yamanouchi Kazuhiko Yamanouchi 
Published: October 2002

A new electrode thickness difference type single phase unidirectional surface acoustic wave (SAW) transducer (ETD-SPUDT), which has λ/4 narrow-gap electrodes is investigated. The ETD-SPUDT is fabricated by cutting part of a meander-line electrode using the shadow of the resist pattern. The theoretical and experimental results show low-loss and large directivity. A low-loss filter for use in the 2 GHz range is fabricated on 128° Y-X LiNbO3 by optical photolithography techniques and for use in the 5 GHz range is fabricated by electron beam exposure. The results show a 3.0 dB insertion loss at 2 GHz and a 4.1 dB loss at 5 GHz.
Acoustic Properties of Surfactant Microbubbles in Relation to their Lifetime In Vitro as Determined by Diffusion
Authors: Man Chan Man Chan , Kawan Soetanto Kawan Soetanto , Motoyoshi Okujima Motoyoshi Okujima 
Published: October 2002

In this study, to make microbubbles less than 10 µm and to extend their lifetime, sodium laurate is chosen as the material for the coating of microbubbles. In studies of ultrasound contrast agents, the authors are the first to report on the use of sodium laurate as the material for manufacturing the microbubble contrast agent. In addition, the method of producing microbubbles using a syringe is proposed. Using sodium laurate and the syringe method, microbubbles with diameter less than 10 µm are produced. From the result of simulation, it is found that the dissolved gas concentration in the solution surrounding microbubbles plays an important role in determining microbubble lifetime. Microbubbles without coating are calculated to have a lifetime of less than 1 min when the dissolved concentration of gas is about 90%. On the other hand, the lifetime of microbubbles made from sodium laurate is about 5 min longer than the calculated lifetime. Therefore, it is hypothesized that when the dissolved gas in the solution is above a certain level, the mechanism governing annihilation of microbubbles is the dissolution of the surfactant coating layer into the solution, instead of the diffusion of gas from the microbubbles. Since the dissolution time of surfactants is longer than the dissolution time of gas, the lifetime becomes longer.
Measurement of Structural and Acoustic Intensities Using Near-Field Acoustical Holography
Authors: Kenji Saijyou Kenji Saijyou , Shigeru Yoshikawa Shigeru Yoshikawa 
Published: October 2002

A non contacting method for measuring structural and acoustic intensities is proposed by developing the signal processing in near-field acoustical holography (NAH). The effectiveness of this method is illustrated by applying it to the measurement of radiation from ribbed and unribbed submerged plates. The spatial derivatives for determining the structural intensity are evaluated by a K-space filtration method newly developed by the authors. The experimental data obtained at 928 Hz and 1464 Hz are selected for specific and detailed investigation. The attached ribs have a small influence on the structural intensity flow at 928 Hz, so the vibrational mode of the ribbed plate is the same as that of the unribbed plate. However, since the attached ribs control the direction of vibrational energy flow at 1464 Hz, the vibrational mode of the unribbed plate is markedly changed.
Effect of La-Doping on Fatigue in Ferroelectric Perovskite Oxides
Authors: Kaoru Miura Kaoru Miura , Masahiro Tanaka Masahiro Tanaka 
Published: October 2002

We investigated the effect of La-doping on fatigue in La-doped lead zirconate titanate (PLZT), using the discrete variational Xα cluster method. Our calculations show that the energies of the La 4f states lie between those of the O 2p states and the Ti 3d states just above the Fermi level, and also that remaining electrons prefer to occupy the La 4f states rather than the Ti 3d states. Since the origin of fatigue in lead zirconate titanate (PZT) is the occupancy of Ti 3d states by remaining electrons from oxygen vacancies, we conclude that PLZT is less susceptible to fatigue than PZT because the remaining electrons occupy the La 4f states.
Lamellar Structure in Melted-Slowly Cooled Vinylidene Fluoride/Trifluoroethylene (86/14) mol% Copolymer
Authors: Sunao Sasaki Sunao Sasaki , Kohji Kubo Kohji Kubo , Akira Funato Akira Funato , Akio Chiba Akio Chiba 
Published: October 2002

Lamellar structure, and its thermally induced changes in melted-slowly cooled vinylidene fluoride/trifluoroethylene (86/14) mol% copolymer were studied by scanning electron microscopy (SEM) and small-angle X-ray scattering (SAXS). SAXS intensity data observed at room temperature showed peaks at arounds≃7.5 ×10-3Å-1ands≃1.35 ×10-3Å-1, the latter of which is caused by thick lamellar stacks such as those observed by SEM (sis the magnitude of the scattering vector). During the heating process, the higher-angle peak disappeared at 147–155°C, while the lower-angle peak disappeared at around 170°C (the melting point of the sample). These SAXS data were analyzed by fitting to lamellar stack models. For the data in the range 25–147°C, a model in which thin and thick lamellar stacks coexist was used. For the data in the range 155–165°C, a model in which only thick lamellar stacks exist was used. The calculated intensities were in good agreement with the observed intensities, which demonstrates that in the range 25–147°C the copolymer is composed of stacks of lamellae about 85 Å thick and stacks of lamellae about 570 Å thick, and that in the range 155–165°C it is composed of only the thick lamellar stacks. The mean crystallinity of the thin lamellar stacks was found to decrease markedly with increasing temperature, which indicates that thin lamellar stacks disappear in the range 147–155°C due to the melting of the crystals within them.
Theoretical Study of Current and Barrier Height between Aluminum Tip and Silicon Surface in Scanning Tunneling Microscopy
Authors: Nobuhiko Kobayashi Nobuhiko Kobayashi , Kenji Hirose Kenji Hirose , Masaru Tsukada Masaru Tsukada 
Published: October 2002

The first-principles calculations for the electronic structure of the aluminum
tip and the silicon surface in scanning tunneling microscopy are performed
using the recursion-transfer matrix method, which is an effective method for
exploring the microscopic electronic states of a bielectrode system under
electric field and current.
The atomic-scale current distribution and the potential
barrier between the tip and the surface are presented. It is revealed that
the opening of a hole in the potential barrier occurs when the tip-sample
distance is 10 a.u. at a surface bias of +2.0 V.
Positive Ions in RF Discharge Plasma of CF 4 Gas in a Planar Diode
Authors: Itsuo Ishikawa Itsuo Ishikawa , Shinya Sasaki Shinya Sasaki , Kazuya Nagaseki Kazuya Nagaseki , Yukinori Saito Yukinori Saito , Shinji Suganomata Shinji Suganomata 
Published: October 2002

Positive ions were measured in situ by direct sampling from CF4 discharge space at 13.56 MHz using a quadrupole mass spectrometer. CF3
+ is observed predominantly with smaller amounts of CF2
+ and CF+. With increasing RF power, both CF2
+ and CF+ shift to the lower energy side of CF3
+, and their intensities tend to increase. Such a phenomenon is also observed as controlling the potential of a sampling tip externally. These seem to suggest that CF2
+ and CF+ are produced mainly in the sheath region.
Optical Disc Track Pitch Variation Measurement Using Two Readout Beams
Authors: Kurokawa Kotaro , Eguchi Naoya , Arai Masayuki , Shin Masuhara Shin Masuhara , Hiroshi Ooki Hiroshi Ooki 
Published: October 2002

At present high-density optical discs have narrow track pitch values, and hence it is necessary not only to verify the precision of the track pitch, but also to determine the degree of track pitch variation. Track pitch variation (T
P
V) is commonly measured using scanning electron, laser scanning and scanning tunneling microscopies. However, these methods are time consuming and it is difficult to take T
P
V readings from large areas of the disc. We developed a T
P
V measurement system based on an optical disc player with two readout beams, and using this system we can rapidly measure the T
P
V over the whole disc surface. In this paper, we describe our T
P
V measurement system and present the results of T
P
V measurements taken from a disc containing continuous grooves with a track pitch of 0.84 µm. We found that the T
P
V of these grooved discs ranged from 30 nm to 100 nm peak-to-peak (pk-pk) with a typical value of 40 nm pk-pk. The measurement resolution of our instrument is about 10 nm pk-pk.
Influence of Exterior Corona on Discharge Voltage of Small Gap in SF6 Gas under Pulse Voltage
Authors: Kamatani Humihiro , Watabe Katunori , Mitsuyoshi Onoda Mitsuyoshi Onoda , Hiroshi Nakayama Hiroshi Nakayama 
Published: October 2002

The effect of a corona initiated from a needle electrode, which is located near a sphere electrode keeping apart from a plane electrode,on the discharge voltage of the sphere-plane gap under pulse voltages in SF6 gas was investigated . The condition of corona initiation and development depended on the resistance which was connected to the high voltage. With increase in the resistance,the discharge voltage increased considerably and reached a maximum at about 5 M Ω for a pulse rise time of 0.5 µs.
Field-Excited Electron Emission from ( 1-y)Pb(Mg 1/3Nb 2/3)O 3-yPbTiO 3 Ceramic
Authors: Yasuhiro Kuratani Yasuhiro Kuratani , Masanori Okuyama Masanori Okuyama , Yoshihiro Hamakawa Yoshihiro Hamakawa 
Published: October 2002

Electron emission from a (1-y)Pb(Mg1/3Nb2/3)O3-yPbTiO3 (PMN-PT) ferroelectric ceramic plate has been observed in vacuum by applying a pair of bipolar pulse voltages. The emission is observed even at temperatures above the Curie temperature, as is that of a lead-zirconate-titanate (PZT) ceramic plate. The amount of emitted charge from PMN-PT ceramic is about 5 times larger than that from PZT ceramic, and increases with increasing pulse width. Furthermore, the temperature dependence of the emitted charge suggests that the amount of emitted charge depends strongly on the dielectric constant of the sample. It is considered that the emission is induced by abrupt change of dielectric flux as well as the polarization reversal.
Growth and Characterization of CeO2Films on Sapphire Substrates by Sputtering Process
Authors: Lin Ran-Jin , Chen Lih-Juann , Lin Lih-Jiaun , Yu Yueh-Chung , Wang Chang-Wan , Lin Erh-Kang 
Published: October 2002

Two-inch-diameter CeO2films on R-plane (1*BAR*1*BAR*02) sapphire substrates have been prepared using an on-axis rf magnetron sputtering method. The effects of postannealing treatment, sputtering gas pressure and substrate temperature on the orientation, crystallinity and surface morphology of the CeO2films have been investigated. The (100)-preferred CeO2films with high crystallinity are grown at 820° C and 0.15 Torr and have a full width at half-maximum value of the rocking curve of (200) planes of 0.15°. The spatial variation of thickness of the CeO2films across the 2-inch substrate is about 5.8%. Thec-axis oriented YBa2Cu3Ox(YBCO) films grown on sapphire substrates with a (100)-preferred CeO2buffer layer of 100 nm are made. The YBCO films have superconducting properties with theTcbeing 88–90 K andJc(77 K, 0 T) being (1–3)×106A/cm2.
Compositional Modulation of Two-Dimensional Layered Perovskite (RNH3)2Pb(Cl, Br, I)4 and Its Optical Properties
Authors: Nobuaki Kitazawa Nobuaki Kitazawa 
Published: October 2002

The compositional modulation of two-dimensional layered perovskites, (RNH3)2Pb(X, I)4(R: C6H5C2H4-; X: Cl, Br), and optical properties of these materials were investigated. Thin films of microcrystalline (RNH3)2- Pb(X, I)4 were successfully fabricated by the spin-coating method. X-ray diffraction spectra revealed that these materials could be regarded as inorganic/organic superlattice structures. In the spectra obtained for the (RNH3)2Pb(Br, I)4 films, a strong exciton absorption band was observed even at room temperature, and the peak position shifted continuously towards the blue and violet regions. The exciton absorption bands observed in the spectrum of (RNH3)2Pb(X, I)4 mixed crystal were consistent with the 6s to 6p transition of Pb2+. The peak shift of the exciton absorption bands of these materials could be explained by the valence band structure composed of the Pb(6s) orbital which was hybridized with the I(5p) and X(np) orbitals.
Extremely Large Amplitude Random Telegraph Signals in a Very Narrow Split-Gate MOSFET at Low Temperatures
Authors: Hiroki Ishikuro Hiroki Ishikuro , Takuya Saraya Takuya Saraya , Toshiro Hiramoto Toshiro Hiramoto , Toshiaki Ikoma Toshiaki Ikoma 
Published: October 2002

We have observed very large amplitude (≈90%) random telegraph signals (RTS) near the pinch-off voltage at very low temperature (1.5 K) in a very narrow, short channel n-MOSFET fabricated by a split-gate technique on an silicon on insulator (SOI) substrate. This large amplitude of RTS can be explained by numerical calculation which takes the potential of the charged trap into account.
Fabrication of Lead Iron Niobate Films on Si Substrate by Pulsed Laser Deposition
Authors: Xin-Rong Wang Xin-Rong Wang , Shou-Shan Fan Shou-Shan Fan , Qun-Qing Li Qun-Qing Li , Bing-Lin Gu Bing-Lin Gu , Xiao-Wen Zhang Xiao-Wen Zhang 
Published: October 2002

Ferroelectric Pb(Fe1/2Nb1/2)O3 (PFN) films were heteroepitaxially grown on Si (100) substrates by pulsed laser deposition. The optimum conditions to form the (100) oriented PFN perovskite phase were at a substrate temperature of 700°C with an oxygen pressure of 200 mTorr. The Pb content in the target was found to be essential to the formation of the perovskite phase in PFN films. Heterostructures consisting of PFN/La0.5Sr0.5CoO3 (LSCO) films were prepared on Si (100) substrates to evaluate the dielectric and ferroelectric properties of the films. Ferroelectricity in these films was confirmed by the presence of hysteresis loops, with a remnant polarization of 0.2 µC/cm2 and coercive field of 5.12 kV/cm. The room-temperature dielectric constant measured at 10 kHz was 194 and the dissipation factor was 0.7.
Microstrip Gas Chamber for X-Rays and Neutrons
Authors: Yasushi Hayakawa Yasushi Hayakawa , Yutaka Maeda Yutaka Maeda 
Published: October 2002

The prototype of a microstrip gas chamber (MSGC) has been constructed and tested as an X-ray detector. The calculation of the electric field around microstrips suggests that the process of gas amplification, which is realized with a smaller potential difference than that of a multiwire proportional chamber (MWPC), is unique. The result, however, shows that the MSGC operates like a conventional MWPC and has energy resolution better than 30% in terms of full width at half-maximum at 5.9 keV. In addition, this gas chamber can be used as a neutron detector by filling it with 3He and CF4 gases.
An Application of Polyphenylsilsesquioxane (PPSQ) to Organic Anti Reflective Coating (ARC)
Authors: Minami Shintaro , Etsushi Adachi Etsushi Adachi , Hiroshi Adachi Hiroshi Adachi 
Published: October 2002

A Polyphenylsilsesquioxane (PPSQ) is an inorganic polymer that has a cis-syndiotactic double chain structure [J. F. Brown, Jr.: J. Polym. Sci. 1C (1963) 83]. By mixing a dye that strongly absorbs the i-line with PPSQ in solution, PPSQ obtained by means of conventional spin-coating can be used as an anti reflective coating (ARC). Since the PPSQ ARC has a large absorbance k value, its reflectance depends little on its thickness, and the thickness uniformity of PPSQ film is superior even if it is formed by spin coating. By using this PPSQ ARC, no reflective notching or linewidth variation of the photoresist pattern are observed.
Study of a Length Coefficient for an Extended Drift-Diffusion Model for Metal-Oxide-Semiconductor (MOS) Device Simulation
Authors: Ken-ichiro Sonoda Ken-ichiro Sonoda , Koji Kanno Koji Kanno , Kenji Taniguchi Kenji Taniguchi , Chihiro Hamaguchi Chihiro Hamaguchi 
Published: October 2002

A length coefficient for an extended/augmented drift-diffusion model for device simulation was extracted under an exponentially increasing electric field using a multi-valley-band Monte Carlo simulator. The length coefficient increases with electric field and tends to saturate at 0.026 µm, which is half of the previously reported value [Appl. Phys. Lett. 52 (1988) 141]. It was also shown that the coefficient is independent of the low-field mobility.
Low-Temperature Epitaxial Growth of CeO 2(110)/Si(100) Structure by Evaporation under Substrate Bias
Authors: Tomoyasu Inoue Tomoyasu Inoue , Yasuhiro Yamamoto Yasuhiro Yamamoto , Masataka Satoh Masataka Satoh 
Published: October 2002

Epitaxial growth of CeO2 layers on silicon (100) substrates is studied using electron-beam evaporation under substrate bias application in an ultrahigh vacuum. Both negative and positive biases are proved to be effective for lowering the epitaxial temperature. Sample current characteristics are measured as a function of the bias voltage. Under negative bias condition, as the bias voltage increases, the sample current varies from negative to positive with a transition point at -42 V and then reaches a saturation value of ∼ +4 µA above -60 V. Use of a negative bias of -60 V leads to epitaxial growth temperature lowering of at least 40°C. Under positive bias application, the sample current is negative and increases with the bias voltage, where the sample current components are anions and electrons (46%) as determined by mass separation with magnetic field application. It is experimentally clarified that the degree of enhancement of epitaxial growth is greater than that in the negative bias experiment (epitaxial growth temperature lowering of more than 55°C) and the enhancement is attributed to the electron component. It is found that a negative current of ∼ -0.15 mA flows at zero bias, indicating that even in conventional evaporation, electrons somewhat promote epitaxial growth.
Blue-Green Electroluminescence in Copolymer Based on Poly(1,4-phenylene ethynylene)
Authors: Kazuya Tada Kazuya Tada , Mitsuyoshi Onoda Mitsuyoshi Onoda , Masaharu Hirohata Masaharu Hirohata , Tsuyoshi Kawai Tsuyoshi Kawai , Katsumi Yoshino Katsumi Yoshino 
Published: October 2002

Optical characteristics of poly(2,5-dialkoxy-1,4-phenylene diethynylene- co-2,5-pyridinylene) (ROPPE-Py) were investigated. Intense blue-green electroluminescence (EL) emission was observed in light emitting diode (LED) with Al/ROPPE-Py/indium-tin-oxide (ITO) structure. This result suggests that triple bonds in the main chain are resopnsible for the blue shift and enhancement of EL, due to the shortening the effective conjugation length and effective confinement of excitons or exciton-polarons. However,	the effects of triple bonds were suppressed by the introduction of electron-rich moieties in the main chain such as poly(2,5-dialkoxy-1,4-phenylene diethynylene- co-9,10-anthracenylene) (ROPPE-An). Electronic energy structures obtained from optical absorption spectra and cyclicvoltammetry measurements confirmed the effect of the electron-rich moieties, which is due to the delocalization of π-electrons and the enhancement of interchain interactions.