ILU factorization well suited to the vector processor using a variant of the 5-point difference scheme

The implementation on the vector processor of Incomplete LU factorization in the Preconditioned Conjugate Gradient method and other Preconditioned CG-like methods for the numerical solutions of the partial differential equations is discussed. For sufficient vectorization, a variant of the standard 5-point difference scheme for 2-dimensional problems is introduced. The convergence property of ILU factorization for this variant is examined in comparison with that vectorized with the usual hyperplane ordering method for the standard 5-point difference scheme on the vector processor. The efficiency and effectiveness of this factorization for the variant of the difference scheme is demonstrated through several computational experiments.     

Photocatalytic Activity of a TiO<Subscript>2</Subscript> Photocatalyst Doped with C<Superscript>4+</Superscript> and S<Superscript>4+</Superscript> Ions Having a Rutile Phase Under Visible Light

C⁴⁺ and S⁴⁺-codoped titanium dioxide (TiO₂) having a rutile phase was prepared. By doping C⁴⁺ and S⁴⁺ ions into a TiO₂ lattice, the absorption edge of rutile TiO₂ powder was largely shifted from 400 to 700 nm. 2-Methylpyridine and methyleneblue were photocatalytically oxidized at high efficiency on C⁴⁺ and S⁴⁺-doped TiO₂ under visible light at a wavelength longer than 5 nm.     

Outdoor autonomous navigation using SURF features

In this article, we propose a speeded-up robust features (SURF)-based approach for outdoor autonomous navigation. In this approach, we capture environmental images using an omni-directional camera and extract features of these images using SURF. We treat these features as landmarks to estimate a robot’s self-location and direction of motion. SURF features are invariant under scale changes and rotation, and are robust under image noise, changes in light conditions, and changes of viewpoint. Therefore, SURF features are appropriate for the self-location estimation and navigation of a robot. The mobile robot navigation method consists of two modes, the teaching mode and the navigation mode. In the teaching mode, we teach a navigation course. In the navigation mode, the mobile robot navigates along the teaching course autonomously. In our experiment, the outdoor teaching course was about 150 m long, the average speed was 2.9 km/h, and the maximum trajectory error was 3.3 m. The processing time of SURF was several times shorter than that of scale-invariant feature transform (SIFT). Therefore, the navigation speed of the mobile robot was similar to the walking speed of a person.     

The roles of the Trommsdorff–Norrish effect in phase separation of binary polymer mixtures induced by photopolymerization

Influence of the Trommsdorff–Norrish (T–N) effect on the phase separation of methyl methacrylate (MMA)/poly(ethyl acrylate) (PEA) mixtures undergoing photo-polymerization was examined by a combination of several experimental techniques. By FT-IR spectroscopy, it was found that the polymerization conversion explosively increases at the onset of this T–N effect. The characteristic irradiation time τ at which this effect occurs, strongly depends on the light intensity and gradually shifts to early time as the irradiation intensity increases. The shrinkage of the mixture observed in situ by laser-scanning confocal microscopy exhibits a transition at a particular irradiation time which is slightly longer than the characteristic time τ. By gel permeation chromatography (GPC), it was found that the molecular weight of the resulting PMMA was almost unchanged before τ and suddenly increases about an order of magnitude after the onset of the auto-acceleration effect. Finally, the characteristic length scales of the morphology also quickly increase with irradiation time and are eventually frozen by this T–N effect. These experimental results indicate that the Trommsdorff–Norrish effect plays an important role in the kinetic processes of polymerization-induced phase separation, suggesting an efficient tool to control the morphology of the polymerizing mixture.     

取代聚苯乙炔环状三聚体的合成

以对溴苯酚为原料,经四步反应合成一种取代苯乙炔单体4-乙炔基-(2,6)二羟甲基-1-十二烷基酚醚。利用手性的铑催化剂引发聚合,得到高分子量的螺旋聚合物,通过GPC和CD对分子量和螺旋结构进行表征。最后通过光环化反应高效合成了环状三聚体,并通过1HNMR和GPC确认其化合物结构。     

Synthesis of stable and soluble one-handed helical poly(substituted acetylene)s without chiral pendant groups via polymer reaction in membrane state

A soluble and stable one-handed helical conjugated polymer without the coexistence of any other chiral moieties was successfully synthesized by asymmetric-induced polymerization of a chiral monomer having two hydroxyl groups followed by desubstitution of the chiral groups in a solid membrane state. The reason for the success was the polymer reaction was carried out in the membrane state. This is an alternative method to obtain such a unique chiral polymer which was obtained only by the helix-sense-selective polymerization (HSSP) we reported before. In addition the efficiency of the chiral induction was higher than that of the HSSP. It is interesting that the “Membrane state” acted like as if a protecting group.     

Thermoreversible behavior of κ-carrageenan and its apatite-forming ability in simulated body fluid

Osteoconductive materials with self-setting ability have received much attention because their properties allow developing injectable materials for bone defects. Thermosensitive hydrogel with ability of bone-like apatite formation in a body environment is a candidate of injectable bone fillers with osteoconductivity because the apatite formation on materials is an essential to show osteoconduction. The present study focused on the development of a thermosensitive hydrogel through modifications of the sulphonic groups of the polysaccharide, κ-carrageenan, with potassium chloride (KCl) and calcium chloride (CaCl₂). We found that the gelation temperature of κ-carrageenan solutions increased with increasing amounts of K⁺ ions. Apatite formation was observed on the gel after exposure to simulated body fluid for 0.5 day when the gel was prepared with a molar ratio of Ca²⁺/sulfonic groups = 1.5. These results indicate that a thermosensitive κ-carrageenan hydrogel with apatite-forming ability was obtained through the incorporation of K⁺ and Ca²⁺ ions into the solution.     

Cloning and characterization of a β-N-acetylglucosaminidase (BmFDL) from silkworm Bombyx mori

In insects, β-N-acetylglucosaminidase (GlcNAcase) participates in critical physiological processes such as fertilization, metamorphosis, and glycoconjugate degradation. Insects produce glycoproteins carrying paucimannosidic-type N-glycans, the terminal GlcNAc residue of which is cleaved by a GlcNAc-linkage specific GlcNAcase, also known as the fused lobes (FDL) protein. To obtain information on the structure of GlcNAcases and insight into their contribution to physiological processes, we cloned Bombyx mori FDL (BmFDL) from silkworm larvae. The full-length cDNA (1.9 kb) encoded a protein of 633 amino acids with 42% amino acid sequence identity to Drosophila melanogaster FDL (DmFDL). Recombinant BmFDL cleaved only β-1,2-linked GlcNAc residues from the α-1,3 branch of biantennary N-glycan. This substrate specificity was similar to that of DmFDL. Microsomal FDL activity was inhibited by anti-BmFDL antibodies. Taken together, our results suggest that BmFDL is a N-glycan-processing GlcNAcase in B. mori.     

Decision methodology of end-milling conditions using data-mining

The purpose of the present study is to apply data-mining methods to support the decision of reasonable cutting conditions. Although an enormous amount of information is listed in a catalog, it is not possible to know all of it. Seen from the viewpoint of the user, this enormous amount of information becomes a hindrance. For example, even if an expert worker does not look at a catalog, in end-mill processing, he can decide the appropriate processing condition efficiently from experience; however, this type of situation creates difficult problems for an unskilled worker or a skilled worker with little experience. The recommended cutting condition for every type of material is listed in a catalog together with the appropriate tool, but it takes much time and labor to search and examine the catalog to find the right tool, and this process is inefficient. The main subject of our research was to support the processing condition of the end-mill for each precision tool efficiently based on end-mill clusters. Our research applied the techniques of data mining, in particular, non-hierarchy clustering and hierarchy clustering, to catalog data. With these techniques, we applied multiple regression analysis and reached the following main conclusions. As a first step, we paid attention to the shape element of catalog data. In addition to using conventional mining processes, we grouped end-mills from the viewpoint of tool shape, which meant the ratio of dimensions, visually by applying the K-means method. We applied variable cluster analysis next to each cluster and extracted an predictor variable to represent each cluster, and we performed multiple regression analysis and derived a cutting condition decision formula. The cutting condition decision formula provided high accuracy. The accuracy was higher than the results achieved through mining of all data. A more highly precise processing condition decision formula was derived by doing mining again, excluding the peculiar data clusters such as small diameter end-mill. We understood what was effective for cutting condition decision to be factors related to blade length and the ratio of the full length, factors which have not been singled out through background knowledge or expert knowledge, but were noticed as an effect of catalog mining.