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21.
22.
Noriaki Suetake Hideaki Kawano Go Tanaka Hidenobu Hashikami Eiji Uchino 《Optical Review》2011,18(6):423-429
In this paper, a new image enlargement method applying the backprojection for lost pixel (BPLP) to the predefined codebook-based
method is proposed. BPLP is a method for image restoration. In BPLP, the eigenspace reflecting the characteristics of an input
image is generated from the remained pixels and is used to restore the missing pixels. In the proposed method, the eigenspace
is replaced by one generated from the predefined codebook (PDC). PDC represents edge-blurring properties in a small image
patch and consists of pairs of low- and high-frequency image patches on various edge patterns. By replacing the PDC-based
estimation of lost high-frequency components with BPLP, a fast image enlargement method retaining its performance can be developed.
Through some experiments, the effectiveness of the proposed method was demonstrated. Especially, it was confirmed that the
processing time of the proposed method was shortened to about 1/50 that of the PDC-based method. 相似文献
23.
Hideaki Iiduka 《Applied mathematics and computation》2011,217(13):6315-6327
Many constrained sets in problems such as signal processing and optimal control can be represented as a fixed point set of a certain nonexpansive mapping, and a number of iterative algorithms have been presented for solving a convex optimization problem over a fixed point set. This paper presents a novel gradient method with a three-term conjugate gradient direction that is used to accelerate conjugate gradient methods for solving unconstrained optimization problems. It is guaranteed that the algorithm strongly converges to the solution to the problem under the standard assumptions. Numerical comparisons with the existing gradient methods demonstrate the effectiveness and fast convergence of this algorithm. 相似文献
24.
Ryota Kudo Masahiro Sonobe Yoshiaki Chino Yu Kitazawa Mutsumi Kimura 《Molecules (Basel, Switzerland)》2020,25(23)
The synthesis and characterization of two phthalocyanine (Pc) structural isomers, 1 and 2, in which four 2,6-di(hexyloxy)phenyl units were attached directly to the 1,8,15,22- or 1,4,15,18-positions of the Pc rings, are described. Both Pcs 1 and 2 exhibited low melting points, i.e., 120 and 130 °C respectively, due to the reduction in intermolecular π-π interaction among the Pc rings caused by the steric hindrance of 2,6-dihexyloxybenzene units. The thermal behaviors were investigated with temperature-controlled polarizing optical microscopy, differential scanning calorimetry, powder X-ray diffraction, and absorption spectral analyses. Pc 1, having C4h molecular symmetry, organized into a lamellar structure containing lateral assemblies of Pc rings. In contrast, the other Pc 2 revealed the formation of metastable crystalline phases, including disordered stacks of Pcs due to rapid cooling from a melted liquid. 相似文献
25.
Yulu Jiang Taro Ozaki Mei Harada Tadachika Miyasaka Hajime Sato Kazunori Miyamoto Junichiro Kanazawa Chengwei Liu Jun‐ichi Maruyama Masaatsu Adachi Atsuo Nakazaki Toshio Nishikawa Masanobu Uchiyama Atsushi Minami Hideaki Oikawa 《Angewandte Chemie (International ed. in English)》2020,59(41):17996-18002
Lolitrems are tremorgenic indole diterpenes that exhibit a unique 5/6 bicyclic system of the indole moiety. Although genetic analysis has indicated that the prenyltransferase LtmE and the cytochrome P450 LtmJ are involved in the construction of this unique structure, the detailed mechanism remains to be elucidated. Herein, we report the reconstitution of the biosynthetic pathway for lolitrems employing a recently established genome‐editing technique for the expression host Aspergillus oryzae. Heterologous expression and bioconversion of the various intermediates revealed that LtmJ catalyzes multistep oxidation to furnish the lolitrem core. We also isolated the key reaction intermediate with an epoxyalcohol moiety. This observation allowed us to establish the mechanism of radical‐induced cyclization, which was firmly supported by density functional theory calculations and a model experiment with a synthetic analogue. 相似文献
26.
Hideaki Fujii 《Tetrahedron》2009,65(51):10623-961
Reduction of cyclopropylmethylamines proceeded under mild reaction conditions in the presence of platinum (IV) oxide catalyst and hydrobromic acid at rt, providing isobutylamines and no linear butylamines. The ring cleavage reaction was widely applicable to cyclopropane rings in various compounds such as N-cyclopropylalkyl, O-cyclopropylalkyl, and C-cyclopropylalkyl derivatives. Although unactivated cyclopropane rings were also cleaved, the cyclobutane ring was tolerated under the same reaction conditions. 相似文献
27.
Hideaki Tokuyama Hiroshi Sumida Akifumi Kanehara Susumu Nii 《Colloid and polymer science》2009,287(1):115-121
Stimuli-sensitive porous hydrogels prepared with an emulsion templating method developed by the authors are potentially applicable
in the medical and pharmaceutical fields; thermosensitive N-isopropylacrylamide (NIPA) hydrogels having randomly distributed sphere-like cavities have been prepared by the polymerization
in an aqueous phase in an oil-in-water (O/W) emulsion, followed by the washing of oil (oleyl alcohol) microdroplets. The surfactant
plays a dominant role in the preparation of porous hydrogels and the pore size. This study concerns with the surfactant effects
on the stability of pre-gel O/W emulsions. The porous NIPA hydrogels were successfully prepared using the surfactants forming
the stable emulsion and their internal structures and swelling properties were characterized. The O/W emulsions and the porous
hydrogels prepared using various amounts of oil and surfactant were characterized. The information obtained serves for preparation
of porous hydrogels having suitable porous structure for their applications. 相似文献
28.
Keisuke Ohto Hideaki Ishibashi Hidetaka Kawakita Katsutoshi Inoue Tatsuya Oshima 《Journal of inclusion phenomena and macrocyclic chemistry》2009,65(1-2):111-120
Solvent extraction of three alkali metal ions with p-t-octylcalix[6]arene hexacarboxylic acid, p-t-octylcalix[4]arene tetracarboxylic acid, corresponding linear trimeric and monomeric analogs was investigated. Cyclic tetramer selectively extracts sodium ion among alkali ions at extremely low pH, while the corresponding cyclic hexamer, the trimer, and the monomer exhibited only poor extraction ability for all alkali metals examined. The detailed extractive investigation of sodium ions with the cyclic tetramer was carried out. It was found that two sodium ions are simultaneously extracted by a single molecule of calix[4]arene derivative and that the second sodium extraction is facilitated by the uptake of the first sodium. The self-coextraction mechanism of sodium ions proposed in the present paper also strongly supports allosteric coextraction of sodium and other metal ions. In the competitive extraction of four alkali metal ions, potassium ion was slightly extracted as the second ion at low pH region, whereas it was hardly extracted in the individual extraction system. The result also supports the coextraction mechanism and role of the first-extracted sodium ion as an allosteric trigger. The extraction equilibrium constants of the cyclic tetramer and two sodium ions, K ex1 and K ex2, were estimated. 相似文献
29.
Mohammad Kemal Agusta Melanie David Hiroshi Nakanishi Hideaki Kasai 《Surface science》2010,604(3-4):245-251
A theoretical study on the structure and adsorption mechanism of hydrazine (N2H4) on Ni(1 0 0) are presented. The hydrazine molecule was found to adsorb on the surface through one of its nitrogen atom in its anti-conformation. The charge transfer from hydrazine lone pair orbitals played a key role in the formation of the bonding. The mechanism involved in the bonding was found to reduce the necessity of hyper-conjugation interaction, that reduces the gauche effect found in hydrazine at the gas-phase. Upon adsorption to the surface, the reduced interaction resulted in the promotion of a more favored conformation through its anti-conformation. 相似文献
30.
A new butenolide, designated odoratinolide (1), was isolated from the bark of the Vietnamese medicinal plant Machilus odoratissima. Its structure was determined by spectroscopic analyses. 相似文献