Cellular affinity of polyamides having various functional groups. I. Platelet adhesion

Various polyamides having a different density of hydrogen bonding, of hydrophilic character, and containing ionic groups have been synthesized and their blood compatibilities were evaluated in terms of the adhesion behavior of blood platelets on polyamide by the microsphere column method. Polyamides containing anionically charged groups such as carboxylate or sulfonate groups adsorbed fewer blood platelets than those with undissociated carboxylate groups. Polyamides having thioether groups adsorbed fewer platelets than those having ether groups. Introduction of a rigid piperazine unit caused an increase in platelet adhesion.     

Effect of Nano Filler Mixture on the Visual Aspect of Treeing Degradation in LDPE Based Composite

This paper deals with a digest on electrical treeing degradation in nanocomposite of magnesium oxide （MgO） added to a low-density polyethylene （LDPE）. The objective is to elucidate the ＂visual＂ aspects...     

A fault location method for power cables using time–frequency analysis

The pulse radar method is one of the fault location methods for power cables. It locates the breakdown point by measuring the delay time of the echo or the discharge signal coming from the breakdown point. The equipment for the pulse radar method is more compact compared to the Murray loop bridge, and its operation is simpler because sensitive adjustments to the proportions are not needed. However, the signal propagating through the cable may be distorted, depending on the distance and frequency, leading to poor location accuracy. In this report, signal processing in the time–frequency domain is proposed to resolve this problem. The pulse waveforms received at two different terminals of the cable were extracted by a window function, and subsequently Fourier‐transformed in order to calculate the phase difference at an appropriate frequency. Special care was taken for unwrapping the folded phase spectrum. The phase difference was interpreted as the time lag at an identical frequency. The technique was applied to fault location for a full‐size XPLE cable line. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 182(1): 10–17, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22323     

Interconnection between the contact angle (adhesion) hysteresis,slippage on a nanorough solid wall and phononic friction

Similarities between different phenomena such as the wear-less phononic friction, adhesion hysteresis, wetting or contact angle hysteresis, surface dissipation, slippage, ripplons, etc., strongly indicate that the underlying molecular processes are also the same or related, and that they all involve transfer/dissipation of energy between interdigitated molecules. In this work, based on concepts as stable and unstable regions, as well as adiabatic and non-adiabatic motions, the hysteresis as a general phenomenon, and in particular the wetting hysteresis is explained. Previously observed qualitative correlations between friction and hysteretic phenomena are cross-referred and quantified to give some quantitative correlations. Several limitations of the phenomenological interconnections, as explained in this paper, are also discussed.     

Ultrathin poly(ethylene glycol) monolayers formed by chemical vapor deposition on silicon substrates

Poly(ethylene glycol) (PEG) monolayer was formed through the chemisorption of a vapor phase organosilane. Photochemically cleaned silicon substrate covered with native oxide (SiO2/Si) was exposed to a vapor of an organosilane, that is, 2-(methoxy[polyethyleneoxy]propyl) trimethoxysilane (MPEOPS) for 1-7 h at 150 degrees C. The resulting sample surfaces became relatively hydrophobic showing a static water-contact angle of ca. 67 +/- 2 degrees and their thickness was ellipsometrically measured to be ca. 0.8 +/- 0.1 nm. Atomic force microscopy confirmed that the sample surface was extremely smooth and homogeneous. Isoelectric point of the MPEOPS-monolayer-covered SiO2/Si substrate was measured to be at around pH 4.9, which was close to that of the methoxytri(ethylene glycol)-terminated alkanethiol SAM on gold (pH 4.3). Furthermore, we demonstrated micropatterning of the MPEOPS monolayer based on a direct photolithography using 172 nm VUV light through a photomask. A well-defined microstructure composed of 5 microm x 25 microm rectangular features was successfully fabricated on a MPEOPS monolayer surface. Subsequently treated it by spatially defined CVD treatment using aminosilane molecule, binary microstructures composed of PEG and amino-terminated surfaces were successfully fabricated.     

DC conduction and electrical breakdown of MgO/LDPE nanocomposite

To understand basic electric properties of nano-sized magnesium oxide (MgO) / low-density polyethylene (LDPE) nanocomposite under DC voltage application, the volume resistivity, the space charge distribution and the breakdown strength were investigated. By the addition of nano-sized MgO filler, both the DC breakdown strength and the volume resistivity of LDPE increased. At the average DC electric field of about 85 kV/mm and more, a positive packet space charge was observed in LDPE without MgO nano-filler, whereas a little homogeneous space charge was observed in MgO/LDPE nanocomposite material at the front of electrode. From these results, it is confirmed that the addition of MgO nano-filler leads to the improvement of DC electrical insulating properties of LDPE.     

Effects of electrode materials on freezing of supercooled water in electric freeze control

In order to clarify effects of electric charge on freezing of supercooled water, experiments were carried out with various kinds of electrodes in supercooled water. Water sample was kept in a test tube and cooled down at a constant cooling rate. When the water sample was maintained under a supercooling state, an electric charge was applied to the water sample with a small electric current. The degree of supercooling was measured continuously. Then the degree of supercooling at freezing was determined. Six kinds of materials were used for electrodes. Those materials were Aluminum, Copper, Argentum, Aurum, Platinum and Carbon. It was found that the effects of electric charge were distinct according to the material used for electrodes. The degree of supercooling at freezing was the lowest in the case of Aluminum. On the other hand, the highest value of the degree of supercooling at freezing was obtained in the case of carbon. The reason for the difference in the degree of supercooling at freezing by six materials was discussed.     

Effect of crystallinity of condensation polymers on platelet adhesion

Various polyamides and polyesters having different numbers of methylene groups in their repeating units have been synthesized and their blood compatibilities have been evaluated in terms of the adhesion behavior of blood platelets on the surface of these condensation polymers by a micro-sphere-column method. The number of methylene groups in the repeating units of polyamides and polyesters influenced the adhesion behavior of platelets and there was an optimum number of methylene groups each in polyamides and polyesters. Poly(hexamethylene terephthalamide) and poly(pentamethylene terephthalate) adsorbed platelets in the smallest number in the polyamide and polyester series, respectively. Blood platelets were adsorbed on polyamides in smaller numbers than on corresponding polyesters. It was found that the platelet adhesion on the surface of polyamides and polyesters was closely related to their crystallinities and the number of the adsorbed platelets decreased linearly with increasing their relative crystallinity.     

Dependency-directed control of text generation using functional unification grammar

In text generation, various kinds of choices need to be decided. In conventional frameworks, which we callone-path generation frameworks, choices are made in an order carefully designed in advance. In general, however, since choices depend on one another, it is difficult to make optimal decisions in such frameworks. Our approach to this issue is to introduce the revision process into the overall generation process. In our framework, revision of output texts is realized as dependency-directed backtracking (DDB). As well as Justification-based Truth Maintenance System (JTMS), we maintain dependencies among choices in a dependency network. In this paper, we propose an efficient implementation of DDB for text generation using functional unification grammar (FUG). We use bindings of logical variables in Prolog and destructive argument substitutions to decrease the overhead of handling a dependency network. This paper describes the algorithm in detail and shows the results of preliminary experiments to demonstrate the performance of our implementation.