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Institution

Tokyo University of Science

EducationTokyo, Japan
About: Tokyo University of Science is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Thin film & Enantioselective synthesis. The organization has 15800 authors who have published 24147 publications receiving 438081 citations. The organization is also known as: Tōkyō Rika Daigaku & Science University of Tokyo.


Papers
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Journal ArticleDOI
TL;DR: In this paper, stable and monodispersive polyion complex micelles were prepared in an aqueous milieu through electrostatic interaction between a pair of oppositely-charged block copolymers with poly(ethylene glycol) segments.
Abstract: Stable and monodispersive polyion complex micelles were prepared in an aqueous milieu through electrostatic interaction between a pair of oppositely-charged block copolymers with poly(ethylene glycol) segments : poly(ethylene glycol)-poly(L-lysine) block copolymer (PEG-P(Lys)) and poly(ethylene glycol)-poly(α,β-aspartic acid) block copolymer (PEG-P(Asp)). It was confirmed from photon correlation spectroscopy (dynamic light scattering) that the scaled average characteristic line width (Γ/K 2 ) was independent of the magnitude of the scattering vector (K 2 ), and the diffusion coefficient (D T ) kept constant regardless of the concentration, indicating that the polyion complex micelles were spherical particles without any secondary aggregates. Further, polydispersity indexes (μ2/Γ 2 ) were always less than 0.1 in the range of the measured concentration (1-10 mg/mL). The hydrodynamic radius at infinite dilution of polyion complex micelles was then determined to be 15.2 nm by using the Stokes-Einstein equation. The unimodal size distribution with d w /d n of 1.07 was confirmed from the correlation function profile by the histogram analysis. The size of polyion complex micelles was unchanged even after a 1-month storing, suggesting that the polyion complex micelles are in thermodynamic equilibrium. Viscosity measurement as well as laser-Doppler electrophoresis provided evidence of the stoichiometry of the polyion complex micelles formation. These polyion complex micelles have potential utility as vehicles for charged compounds, i.e., proteins and nucleic acids, in the field of drug delivery.

754 citations

Journal ArticleDOI
TL;DR: In this article, the dielectric, ferroelectric and piezoelectric properties of perovskite and bismuth layer-structured BLSF (BLSF) ceramics are described as superior candidates for lead-free, lead free, and low-cost piezolectric materials to reduce environmental damages.
Abstract: Dielectric, ferroelectric and piezoelectric properties of perovskite ferroelectric and bismuth layer-structured ferroelectric (BLSF) ceramics are described as superior candidates for lead-free piezoelectric materials to reduce environmental damages. Perovskite type ceramics seem to be suitable for actuator and high power applications that are required a large piezoelectric constant, d 33 (>300 pC/N) and a high Curie temperature, T c (>200 °C). For BaTiO 3 (BT)-based solid solutions, that is, (1 − x )BaTiO 3 − x (Bi 0.5 K 0.5 )TiO 3 [BTBK − 100 x ] ceramics, the T c increases with increasing the amount of x . BTBK-20 + MnCO 3 0.1 wt.% ceramic shows the high T c than 200 °C and the electromechanical coupling factor, k 33 = 0.35. In the case of a (Bi 1/2 Na 1/2 )TiO 3 − b BaTiO 3 − c (Bi 1/2 K 1/2 )TiO 3 [BNBK (100 a /100 b /100 c )] solid solution ceramics, the d 33 and T c are 191 pC/N and 301 °C for the BNBK (85.2/2.8/12), respectively. On the other hand, BLSF ceramics seem to be excellent candidates as piezoelectric sensors for high temperatures and ceramic resonators with high mechanical quality factor ( Q m ), and low temperature coefficient of resonance frequency (TC- f r ). Donor-doped Bi 4 Ti 3 O 12 ceramics such as Bi 4 Ti 3− x Nb x O 12 [BITN- x ] and Bi 4 Ti 3− x V x O 12 [BITV- x ] show high T c than 650 °C. The k 33 value of the grain-oriented (HF) BITN-0.08 ceramic is 0.39 and is able to keep the same value up to 350 °C. Bi 3 TiTaO 9 (BTT)-based solid solution system, Sr x −1 Bi 4− x Ti 2− x Ta x O 9 [SBTT2( x )] (1 ≦ x ≦ 2), displays the high Q m value (=13500) in (p)-mode at the x = 1.25 composition.

742 citations

Journal ArticleDOI
TL;DR: The technique enables direct 3D fabrication without the use of molds and may become the standard next-generation composite fabrication methodology.
Abstract: We have developed a method for the three-dimensional (3D) printing of continuous fiber-reinforced thermoplastics based on fused-deposition modeling. The technique enables direct 3D fabrication without the use of molds and may become the standard next-generation composite fabrication methodology. A thermoplastic filament and continuous fibers were separately supplied to the 3D printer and the fibers were impregnated with the filament within the heated nozzle of the printer immediately before printing. Polylactic acid was used as the matrix while carbon fibers, or twisted yarns of natural jute fibers, were used as the reinforcements. The thermoplastics reinforced with unidirectional jute fibers were examples of plant-sourced composites; those reinforced with unidirectional carbon fiber showed mechanical properties superior to those of both the jute-reinforced and unreinforced thermoplastics. Continuous fiber reinforcement improved the tensile strength of the printed composites relative to the values shown by conventional 3D-printed polymer-based composites.

722 citations

Journal ArticleDOI
TL;DR: The K2K experiment observed indications of neutrino oscillation after 250 km flight of υμ. as mentioned in this paper The observed number of events in the data corresponding to 4.8 x 1019 protons on target is 56, while 80.1 5.4 + 6.2 is expected.
Abstract: The K2K experiment observed indications of neutrino oscillation after 250 km flight of υμ. The observed number of events in the data corresponding to 4.8 x 1019 protons on target is 56, while 80.1 5.4 +6.2 is expected. Both the decrease of the events and observed spectrum shape distortion are consistent with neutrino oscillation. The probability that the observations are statistical fluctuation of non oscillation is less than 1%. The allowed region of oscillation parameters is consistent with the one obtained from the atmospheric neutrino observation. After the accident of Super-Kamiokande (SK) detector, the reconstruction of SK has finished in 2002 and the K2K experiment resumed in December 2002.

702 citations

Journal ArticleDOI
M. H. Ahn1, E. Aliu2, S. Andringa2, Shigeki Aoki3  +217 moreInstitutions (29)
TL;DR: In this article, measurements of {nu}{sub {mu}} disappearance in K2K, the KEK to Kamioka long-baseline neutrino oscillation experiment are presented.
Abstract: We present measurements of {nu}{sub {mu}} disappearance in K2K, the KEK to Kamioka long-baseline neutrino oscillation experiment. One-hundred and twelve beam-originated neutrino events are observed in the fiducial volume of Super-Kamiokande with an expectation of 158.1{sub -8.6}{sup +9.2} events without oscillation. A distortion of the energy spectrum is also seen in 58 single-ring muonlike events with reconstructed energies. The probability that the observations are explained by the expectation for no neutrino oscillation is 0.0015% (4.3{sigma}). In a two-flavor oscillation scenario, the allowed {delta}m{sup 2} region at sin{sup 2}2{theta}=1 is between 1.9 and 3.5x10{sup -3} eV{sup 2} at the 90% C.L. with a best-fit value of 2.8x10{sup -3} eV{sup 2}.

672 citations


Authors

Showing all 15878 results

NameH-indexPapersCitations
Kazunori Kataoka13890870412
Yoichiro Iwakura12970564041
Kouji Matsushima12459056995
Masaki Ishitsuka10362439383
Shinsuke Tanabe9872237445
Tatsumi Koi9741150222
Hirofumi Akagi9461843179
Clifford A. Lowell9125823538
Teruo Okano9160528346
László Á. Gergely8942660674
T. Sumiyoshi8885562277
Toshinori Nakayama8640525275
Akihiko Kudo8632839475
Hans-Joachim Gabius8569928085
Motohide Tamura85100732725
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202356
2022137
20211,357
20201,481
20191,510
20181,429