Poly(ethylene oxide) macromonomers

Summary Poly(ethylene oxide) macromonoraers (M₂) carrying p-vinylbenzyl or methacryloyl group at the -end and methyl or dodecyl group at the -end were prepared, and radical-copolynerized with benzyl methacrylate or styrene (M₁). Relative reactivities of the macroraonomers (1/r₁), were found to be significantly smaller than those of the corresponding model monomers of low molecular weights in all cases where the macromonomer (M₂) and the homopolymer of the comonomer(poly-M₁), are incompatible, supporting our previous suggestion of a repulsion between M₂ and poly-M₁, radical as a factor for retarding their mutual reaction.     

A Petri Net-Based Controller for Flexible and Maintainable Sequence Control and its Applications in Factory Automation

A new type of software system for an industrial sequence controller is proposed. In this system, a control program is described with the Petri net-like language named Control-net (C-net). This language improves control software maintainability and flexibility. An efficient C-net interpretation schema for real-time control is presented and an overhead time evaluation model of the proposed schema is developed. Through the model analysis and measurement of the response time of an interpreter on a microcomputer, it is proved that the interpretation schema satisfies the required response time. Finally, a microcomputer based controller named Station Controller (SCR) in which the presented C-net interpreter was installed is described and several applications of this controller to real systems are illustrated.     

A PHYSICAL CHEMICAL EXPLANATION FOR DETERIORATION IN THE HOT WATER PROCESSABILITY OF ATHABASCA OIL SAND DUE TO AGING

The oxidation of sulphide minerals during storage of Athabasca oil sands causes solubilization of inorganic salts which affect recovery of bitumen during hot water extraction. DLVO and Ionizable Surface Group Model theories accurately predict that the level of soluble salts produced is sufficient to cause coagulation of the fine particles during the process which leads to a deterioration in froth quality and loss of bitumen recovery. The rate of aging is specific to each oil sand but storage of oil sands under an inert atmosphere in air-tight container at sub-zero temperatures will minimize oxidation.     

High density culture of Coptis japonica cells increases berberine production

A high density culture method was devised to improve the yield of berberine from highly productive cells of Coptis japonica. By adjusting aeration and stirring, Coptis cells were cultured at densities of up to 75 g dm^?3 (dry weight) in a culture tank fitted with a hollow-paddle type stirrer. Whereas a maximum density of 30 g dm^?3 of C. japonica cells could be used in ordinary batch culture, 48 g dm^?3 could be used in a fed-batch culture in which the amounts of the nutrients in the medium were made proportional to the density of the inoculum. Moreover, in fed-batch culture done with modified medium, the composition of which had been determined from the amounts of components incorporated in cells grown at the usual density for ordinary batch culture, the cell yield was improved to 55 g dm^?3 and the berberine yield to 3.5 g dm^?3.     

Complex of Tertiary Acetylenic Alcohol and Brucine or Sparteine. X-Ray Crystal Structural Study and Application to Optical Resolution

Some tertiary acetylenic alcohols were optically resolved efficiently by complexation with brucine or sparteine. In the latter case, mutual optical resolution of sparteine and the tertiary acetylenic alcohol is possible. For an efficient resolution, the tertiary acetylenic alcohol should have at least one aromatic ring such as phenyl, naphthyl, thienyl as a substituent. The crystal structure of the 1:1 brucine complex and of the 1:1 (-)-sparteine complex of (-)-l-(o-bromophenyl)-1-phenyl-2-propynol ( 1a ) are reported. In both cases, two hydrogen bonds, are important to fix the two components at a close position where mutual chiral recognition is efficient.     

Energy distributions of field emitted electrons from a multi-wall carbon nanotube

Field emission energy distributions of electrons from one of the six pentagons located at the end of a multi-wall carbon nanotube have been measured by means of a high-resolution cylindrical energy analyzer. In a clean pentagon, the sub-peak was obtained at about 500 meV below the main peak, exhibiting a shift with increasing applied voltage. For electrons emitted from an adsorbate onto the pentagon, no fine structure was observed in the spectra. The broadening of the leading edge was also observed for both clean and adsorbed pentagon, indicating the field penetration into the nanotube due to its semimetallic nature. The full-width at half-maximum was 280 meV at the applied voltage of 660 V and increased linearly with applied voltage.     

Formally Self-Dual Codes Related to Type II Codes

Shadows play an important role in the study of self-dual codes. In this note, we give constructions of formally self-dual codes using self-dual codes and their shadows. As an example, a class of binary formally self-dual codes related to extremal Type II code is introduced. This work was partially supported by the Grant-in-Aid for Scientific Research (No. 10740044), the Ministry of Education, Science, Sports and Culture, Japan, and the Sumitomo Foundation (No. 990645), Japan.Keywords:Formally self-dual codes, Type II codes and codes over _2k.     

New results for near-optimal control of linear multiparameter singularly perturbed systems

In this paper, we consider the linear quadratic optimal control problem for multiparameter singularly perturbed systems in which N lower-level fast subsystems are interconnected through a higher-level slow subsystem. Different from the existing methods, a new method is developed to design a near-optimal controller which does not depend on the unknown small parameters. It is shown that the resulting controller in fact achieves an O(||μ||²) approximation to the optimal cost of the original optimal control problem.     

Deposition and microstructure of Ti-containing diamond-like carbon nanocomposite films

Ti-containing diamond-like carbon (DLC) films were deposited by plasma decomposition of CH₄/Ar gas mixtures with an introduction of tetrakis(dimethylamino)titanium (TDMAT, Ti[(CH₃)₂N]₄), which was used as a precursor of titanium. The films deposited were found to be nanocomposite coatings consisting of TiN nanocrystalline clusters and amorphous hydrocarbon (a-C:H), indicating that the nanocrystalline clusters were embedded in the DLC matrix. The crystallinity of TiN clusters, as well as the Ti atomic concentrations in the films, increased with an increase of substrate temperature. The substrate temperature applied to form a crystalline phase in the DLC matrix induced a graphitization of amorphous hydrocarbon matrix. The increase of volume fraction of TiN nanocrystalline clusters in the DLC matrix enhanced the mechanical properties of nanostructured coatings, although the graphite-like structural transition of DLC matrix happened due to the applied heating.