Line-drawing interpretation using probabilistic relaxation

This paper shows that probabilistic relaxation is an effective method in the automatic interpretation of line drawings consisting of lines, symbols, and characters, such as electricity distribution diagrams superimposed on maps. The line interpretation problem has been newly formulated as a labeling problem in which probabilistic relaxation is used to obtain globally consistent results. The proposed automatic interpretation method consists of two stages. The first is segmentation and recognition of primitive components, such as symbols, characters, and long lines. The second is long-line interpretation, where probabilistic relaxation is introduced.     

Synthesis and photodegradation of copolyamides containing α-diketone linkage in the main chain

Copolyamides were prepared from 4,4′-dichloroformylbenzil, adipyldichloride and hexamethylenediamine. The melting points and solubilities of the copolyamides varied with benzil content. The copolyamides were irradiated by u.v. light in solution and in a film. The copolyamide irradiated in solution was still soluble but the copolyamide irradiated in a film was crosslinked. The mechanisms of the photochemical reactions are discussed.     

Etched carbon-fiber electrodes as amperometric detectors of catecholamine secretion from isolated biological cells

Voltammetric electrodes with micrometer dimensions have been fabricated from carbon fibers etched to a conical shape and insulated with poly(oxyphenylene) following literature procedures. The resultant electrode has a tip radius in the micron range. The response of this electrode is compared to a carbon-fiber electrode prepared by sealing a carbon-fiber electrode in a glass pipet (electrode radius greater than 3.5 microns). While the etched electrodes did not follow electrochemical theory as well as the glass-encased electrode, the etched electrode was found to be suitable for the amperometric measurement of the secretion of catecholamines from isolated bovine adrenal cells. Comparable results are only obtained when the two different electrodes are placed 1 micron from the cell surface. When the etched electrode is placed further away, less secretion is observed, because of diffusion and accompanying dilution.     

A Method of Study of Radioactive Tracer Kinetics

This paper presents an approach to the problem of estimating the number of exponential functions and the pertinent parameters in the output of a radioactive tracer kinetic process. In particular, application of a criterion called an information theoretical criterion (AIC) for the estimation of the number of exponential functions is proposed; AIC was introduced by Akaike for the estimation of the order of linear dynamical systems and has been successfully applied for statistical model identification in a wide range of fields. Also, the maximum likelihood method was applied in order to evaluate AIC and to estimate decay constants and coefficients.     

Acetylene–butadiene copolymer for polymer coatings

Low molecular weight, M?_n 1800–2400, and soluble copolymers of acetylene and butadiene were prepared by nickel naphthenate–diethylaluminum chloride catalyst. These copolymers possess high cure tendency to give insoluble and highly crosslinked films. The curing ability can be controlled by the amount of acetylene content in the copolymer and is in the following order: acetylene–butadiene copolymer > tung oil > cis-1,4-polybutadiene ? linseed oil, 1,2-polybutadiene, butadiene–isobutylene copolymer. Chemical modifications of the copolymer such as maleic reaction, metallation by lithium or sodium, graft polymerization by methyl methacrylate, 4-vinylpyridine or vinyl acetate, and epoxidation were also examined. The divinyl methylene in the copolymer gives a high cure tendency and high chemical reactivity.     

Solid state reaction, sintering and Pb removal activity of hydroxyapatite/zirconia layered composite

In order to form a layered hydroxyapatite/zirconia ceramic, the solid state reaction and sintering were examined by the three processes of powder mixture, dry-pressing compaction and tape cast. The solid state reaction between hydroxyapatite and zirconia occurred in the thin width of 10–50 m at interface in a layered composite body. In both sintered layer composites from dry compaction and tape cast, the significant deformation of composite bodies was observed, depending on sintering temperatures. By selecting a sintering temperature of 1200°C, we fabricated a layer ceramic composite of hydroxyapatite/zirconia exhibiting the flat film shape. The tape cast process was useful to form a porous sintered composite of hydroxyapatite and zirconia. The porous composite showed the removal performance of aqueous lead from wastewater.     

Continuous ice slurry formation using a functional fluid for ice storage

A functional fluid composed of an oil–water mixture with an additive is transformed into an ice slurry by cooling while stirring. This paper describes a new continuous ice slurry formation method. Experiments were carried out by varying conditions such as the supply time of functional fluid, the stirrer torque, brine temperature and degree of supercooling. As a result, the characteristics of the ice formation and recovery processes were clarified. It was found that the ice particles gradually became uniform in size and spherical, and grew to 3.5 mm in diameter during about 10 h. The factors influencing the size of formed ice particles were discussed because the larger ice particles were expected to melt more rapidly. The ice particle size was found to increase with decreasing degree of supercooling and cooling rate, and with increasing stirrer wing diameter.     

Effects of absorbed water on the interfacial fracture between two layers of unsaturated polyester and glass

The effects of absorbed water on the interfacial fracture resistance between two layers of unsaturated polyester (UP) and glass of the bilayer specimen were evaluated by measuring a load for producing the fracture by inserting a razor blade into the interface. The specimens were subjected to the cyclic absorption-desorption and the continuous absorption processes of water. The load to initiate the interfacial fracture was markedly lowered by the early absorption process for short period, and then gradually reduced with increasing cycle or period of water absorption, although it slightly recovered after the first great reduction when the specimens were subjected to the soaking process at lower temperatures. The micro-FTIR (ATR) analyses of the detached surface of the UP resin from the glass plate revealed that the water is accumulated in the resin at the interface in the cluster, showing the concentration to increase with increases both in the temperature of environmental water and in the water-soaking period. The IR analyses also demonstrated the hydrolysis reaction to take place on the detached resin surface of specimen exposed to water at high temperature. Thus the accumulated water at the interface may remain and promote the interfacial degradation even under the drying process by various mechanisms like the hydrolysis reaction in hot water environment.     

Comparison of miscibility in poly(N-vinylcarbazole)/polystyrene and polyoxyethylene blends by excimer fluorescence

Summary It is for the first time found that poly(N-vinylcarbazole)(PVCz)/polystyrene (PS) blends have lower miscibility on molecular level than that of PVCz/polyoxyethylene (PEO) blends. This is obtained from excimer fluorescence properties of PVCz in PVCz (9.1–100%)/PS and PVCz (9.6–100%)/PEO blends. Schematic diagrams of phase-separated structure of the PVCz blends are proposed consistent with emission properties and phase-contrast microscopic images. Received: 8 February 2000/Revised version: 21 March 2000/Accepted: 27 March 2000