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Search Results: 1 - 10 of 960 matches for " Osamu Kusakari "
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Wide and Fast Wavelength-Swept Fiber Laser Based on Dispersion Tuning for Dynamic Sensing
Shinji Yamashita,Yuichi Nakazaki,Ryosei Konishi,Osamu Kusakari
Journal of Sensors , 2009, DOI: 10.1155/2009/572835
Abstract: We have developed a unique wide and fast wavelength-swept fiber laser for dynamic and accurate fiber sensing. The wavelength tuning is based on the dispersion tuning technique, which simply modulates the loss/gain in the dispersive laser cavity. By using wideband semiconductor optical amplifiers (SOAs), the sweep range could be as wide as ~180 nm. Since the cavity contains no mechanical components, such as tunable filters, we could achieve very high sweep rate, as high as ~200 kHz. We have realized the swept lasers at three wavelength bands, 1550 nm, 1300 nm, and 800 nm, using SOAs along with erbium-doped fiber amplifiers (EDFAs), and in two laser configurations, ring and linear ones. We also succeeded in applying the swept laser for a dynamic fiber-Bragg grating (FBG) sensor system. In this paper, we review our researches on the wide and fast wavelength-swept fiber lasers.
Evaluation of the Bending Loss of the Hollow Optical Fiber for Application of the Carbon Dioxide Laser to Endoscopic Therapy  [PDF]
Daisuke Kusakari, Hisanao Hazama, Rinna Kawaguchi, Katsunori Ishii, Kunio Awazu
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.34A003

Since carbon dioxide laser is excellent for incision, hemostasis, coagulation, and vaporization of soft tissues, it has been widely applied in clinical treatments as the laser knife. In these days, flexible thin hollow optical fibers transmitting mid-infrared light have been developed, and the application of carbon dioxide laser to endoscopic therapy has become possible. However, it is expected that the irradiation effect is influenced by the change in the laser power at the tip of the hollow optical fiber due to the change in the transmittance by the bending loss. The purpose of this research is to quantitatively evaluate the change in the output power and therapeutic effect by bending the hollow optical fiber in a gastrointestinal endoscope. The change in the transmittance of the hollow optical fiber due to the insertion of the fiber into the endoscope and bending of the head of the endoscope was measured. Then, the relationship between the irradiated laser power and the incision depth for a porcine stomach was investigated. As the results, the most significant decrease in the transmittance of the hollow optical fiber was caused by the insertion of the fiber into the instrument channel of the endoscope, and bending of the head of the endoscope with the angle of 90° decreased the output laser power and incision depth by 10% and 25%, respectively. Therefore, it was confirmed that the bending loss of the hollow optical fiber due to the bending of the head of the endoscope had no significant influence on the endoscopic therapy using the carbon dioxide laser.

Calcium Participates in Secretion of Porphyrin from Shell Gland Epithelial Cells of Japanese Quail (Coturnix coturnix japonica)  [PDF]
Osamu Kai
Open Journal of Animal Sciences (OJAS) , 2019, DOI: 10.4236/ojas.2019.91013

To investigate factors involved in the secretion of protoporphyrin IX (PpIX), a superficial eggshell pigment, from shell gland epithelial cells of Japanese quail, we cultured cells in Ham’s F12 medium with calcium chloride and quail plasma. The addition of hormones (prostaglandin F2α, progesterone, estradiol-17β) to the medium did not change the PpIX concentration in the culture supernatant, but changing the calcium chloride (CaCl2) concentration did: a lower concentration of CaCl2 led to a higher PpIX concentration; 0 mM CaCl2 enhanced the secretion of PpIX from epithelial cells prepared at 5 or 7 mM CaCl2. The result suggests that a drop in concentration of CaCl2 mimics the end of shell calcification and stimulates rapid secretion of PpIX in vivo. Bovine serum albumin was almost as effective

A Unified Ordering for Termination Proving
Akihisa Yamada,Keiichirou Kusakari,Toshiki Sakabe
Computer Science , 2014,
Abstract: We introduce a reduction order called the weighted path order (WPO) that subsumes many existing reduction orders. WPO compares weights of terms as in the Knuth-Bendix order (KBO), while WPO allows weights to be computed by a wide class of interpretations. We investigate summations, polynomials and maximums for such interpretations. We show that KBO is a restricted case of WPO induced by summations, the polynomial order (POLO) is subsumed by WPO induced by polynomials, and the lexicographic path order (LPO) is a restricted case of WPO induced by maximums. By combining these interpretations, we obtain an instance of WPO that unifies KBO, LPO and POLO. In order to fit WPO in the modern dependency pair framework, we further provide a reduction pair based on WPO and partial statuses. As a reduction pair, WPO also subsumes matrix interpretations. We finally present SMT encodings of our techniques, and demonstrate the significance of our work through experiments.
Nagoya Termination Tool
Akihisa Yamada,Keiichirou Kusakari,Toshiki Sakabe
Computer Science , 2014,
Abstract: This paper describes the implementation and techniques of the Nagoya Termination Tool, a termination prover for term rewrite systems. The main features of the tool are: the first implementation of the weighted path order which subsumes most of the existing reduction pairs, and the efficiency due to the strong cooperation with external SMT solvers. We present some new ideas that contribute to the efficiency and power of the tool.
Optimizing the Conditions for Residual Stress Measurement Using a Two-Dimensional XRD Method with Specimen Oscillation  [PDF]
Osamu Takakuwa, Hitoshi Soyama
Advances in Materials Physics and Chemistry (AMPC) , 2013, DOI: 10.4236/ampc.2013.31A002

In order to optimize the conditions for residual stress measurement using a two-dimensional X-ray diffraction (2D-XRD) in terms of both efficiency and accuracy. The measurements have been conducted on three stainless steel specimens in this study. The three specimens were processed by annealing, a cavitating jet in air and a disc grinder, with each method introducing different residual stresses at the surface. The specimens were oscillated in the ω-direction, representing a right-hand rotation of the specimen about the incident X-ray beam. The range of the oscillation, Δω, was varied and optimum Δω was determined. Moreover, combinations of the tilt angle between the specimen surface normal and the diffraction vector, ψ, with the rotation angle about its surface normal, f, have been studied with a view to find the most optimum condition. The results show that the use of ω oscillations is an effective method for improving analysis accuracy, especially for large grain metals. The standard error rapidly decreased with increasing range of the ω oscillation, especially for the annealed specimen which generated strong diffraction spots due to its large grain size.

Role on Moment of Inertia and Vortex Dynamics for a Thin Rotating Plate  [PDF]
Yoshihiro Kubota, Osamu Mochizuki
World Journal of Mechanics (WJM) , 2013, DOI: 10.4236/wjm.2013.36028

In this study, we focused on the lift generation with a thin rotating plate. The objective of this study is to understand the appropriate shape and the role of vortex for rotating thin plate. We determined the shape of the plate through free-flight tests of paper strips and investigated the aerodynamic characteristics of the rotating plate with the selected shape. The rectangular plate with an aspect ratio 7 was relevant from moment of inertia and bending stress. An endplate on a wing tip increased the stability on the lateral vortex structure behind the rotating plate. Velocity field measurement by Particle Image Velocimetry (PIV) showed that the lift force was generated twice in a rotating cycle.

Product Reputation Trend Extraction from Twitter  [PDF]
Aizhan Bizhanova, Osamu Uchida
Social Networking (SN) , 2014, DOI: 10.4236/sn.2014.34024

Micro-blogging today has become a very popular communication tool among the Internet users. Real-time web services such as Twitter allow users to express their opinions and interests, often expressed in the form of short text messages. Many business companies are looking into utilizing these data streams in order to improve their marketing campaigns, refine advertising and better meet their customer needs. In this study, we focus on using Twitter, for the task of extraction product reputation trend. Thus, business could gauge the effectiveness of a recent marketing campaign by aggregating user opinions on Twitter regarding their product. In this paper, we introduce an approach for automatically classifying the sentiment of Twitter messages toward product/brand, using emoticons and by improving pre-processing steps in order to achieve high accuracy.

Synthesis of a Rhodamine-Appended Cyclophane as a Fluorescence Host in Water  [PDF]
Osamu Hayashida, Yu Kaku
Advances in Chemical Engineering and Science (ACES) , 2014, DOI: 10.4236/aces.2014.44044
Abstract: A cationic water-soluble cyclophane (1a) having a rhodamine moiety as a red-fluorescence fluorophore was prepared by reaction of a monoamine derivative of tetraaza[]paracyclophane having three N-t-butoxycarbonyl-β-alanine residues with rhodamine B isothiocyanate, followed by removal of the protecting groups. The guest-binding behavior of 1a toward anionic guests such as dabsyl derivative and 4-(1-pyrene)butanoate was investigated by fluorescence spectroscopy. The results suggested the formation of host-guest complexes with a stoichiometric ratio of 1:1 and the binding constants (K) of the host-guest complexes were evaluated.
Effect of Residual Stress on the Corrosion Behavior of Austenitic Stainless Steel  [PDF]
Osamu Takakuwa, Hitoshi Soyama
Advances in Chemical Engineering and Science (ACES) , 2015, DOI: 10.4236/aces.2015.51007
Abstract: In this paper we demonstrate that the residual stress introduced by several different surface finishes affects the critical current density for passivation and the passive current density in the anodic polarization curve of austenitic stainless steel and that those critical current densities can be reduced by controlling the residual stress by applying a cavitating jet to the backs of specimens. The results show that the current density either increased or decreased depending on the surface finish, and that was decreased by introducing compressive residual stress for all surface finishes.
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