Hiroshi Tsubakihara

Development of a coating technique for inertial confinement fusion plastic targets

Deuterated polystyrene as a target material offers several advantages over other polymers because of the following: (1) it is chemically and physically stable at ordinary conditions, (2) it can be easily formed into spherical shells, and (3) it has a very high fraction of D2/H2 (above ∼99%). As in our previous studies, the fabrication method was basically a utilization of the emulsion technique. This method is well suited to mass‐producing the polymer targets without microprocessing techniques. We have developed a fabrication method for single shell targets and an extension of this technique also enables us to fabricate double shell targets. This new method is faster and less labor intensive than previous techniques. The development of ICF experiments requires multilayer structure targets; we have developed, moreover, a new fabrication technique called the multicoating method. The polymer coating can be fabricated by the application of an emulsion technique. On the other hand, with metal coating, a nonelectroplating method was used, and nickel was employed as the coating metal. The thickness of the polymer coating layer can be controlled with the rotational speed of a stirrer in the emulsion. In the case of nickel coating, it is achieved by controlling the plating bath temperature and immersion time during the plating process. The experiment resulted in the development of a new technique for the fabrication of multilayer targets and low density, thick polymer‐layer‐coated targets.

Development of polyvinyl alcohol shells overcoated with polystyrene layer for inertial confinement fusion experiments

In inertial fusion experiments, the use of polymer shells provides more efficient ablative implosion and significantly reduced radiation preheat compared with the glass shells currently used. We have developed a method of fabricating polyvinyl alcohol (PVA) shells overcoated with a polystyrene (PS) layer. The method utilizes the emulsion technique previously developed by us, and employs three different liquid phases. A 5 wt. % aqueous PVA solution is mixed with a 7 wt. % PS solution in dichloromethane while stirring. The mixture is then poured into a 1 wt. % PS solution in cidhloromethane while stirring. The mixture is then poured into a 1 wt. % aqueous gelatin solution. The resulting emulsion is heated to evaporate the dichloromethane, resulting in solid PS shells encapsulating the PVA solution. The PS shells are subsequently washed and dried in vacuum to drive off the remaining water. As a result, a PVA shell is formed inside an overcoating PS shell which exhibits a good surface quality in the outer dia...

Carrier mobility in vinylidenefluoride-trifluoroethylene copolymer

The carrier mobility of a ferroelectric Vinylidenefluoride-Trifluoroethylene copolymer (VDF: 54 mol%) was measured by the time-of-flight method after irradiation by a KrF excimer laser. The hole and electron mobilities were estimated to be 3×10-6 cm2/Vs and 7×10-6 cm2/Vs, respectively.

Doping Effect on the Electric Current and Molecular Structure of a Vinylidenefluoride-Trifluoroethylene Copolymer

This paper describes the doping influence of the ionic rhodamine 6G (R6G) dye on the electric current of the Vinylidenefluoride-Trifluoroethylene (VDF-TrFE) copolymer induced by irradiation from a TEA CO2 laser. The current of the nondoped sample increases rapidly at the poling field over 0.4 MV/cm, and the current of the doped one has a point of a rapid increase lower than that of the nondoped one. The infrared spectra and the dielectric constants of the undoped and doped samples have been studied. The qualitative analysis shows that the current is affected by the ionic R6G dye.

Effect of Thermal Treatment on the Structural Change of Polyaniline.

大気中および真空中において熱処理されたエメラルディン塩基ポリアニリン (EB) の構造変化を可視紫外および赤外分光スペクトルにより調べた. その結果から筆者らは210℃までとそれ以上の領域の2つの温度領域に分けて考えることができる. 真空中で熱処理した場合, 210℃までの温度増加では構造上の変化はほとんど認められない. それ以上の高温熱処理では, イミン間の鎖間架橋のためのキノイド減少が観察された. 大気中で熱処理した場合には210℃までの低温熱処理で酸素の付加によるEBの構造変化が生じた. さらに高温熱処理ではアミンの水素脱離も生じ, 鎖間架橋反応が進行する.

Dye doping effect of conduction in vinylidenefluoride-trifluoroethylene copolymer

This paper describes the doping influence of the ionic dye, rhodamine 6G (R6G), on the electric current of VDF-TrFE copolymer induced by irradiation with a TEA CO/sub 2/ laser. The current of the undoped sample increases rapidly at poling fields over 0.4 MV/cm, and that of the doped one has a lower rapid increasing point. X-ray diffraction, infrared spectra and dielectric constant measurements of undoped and doped samples are reported. The qualitative analysis shows that the current is affected by ionic dye doping.

Sulfuric Acid-Doping on Thermally Aged Polyaniline.

浸漬する硫酸の水素イオン濃度, 浸漬時間, 温度などを変化させ, 熱処理したポリアニリンのドーピング反応について検討した. 試料はキャスティングにより製膜され, 90～170℃で熱処理した後, 硫酸水溶液に浸潰した. ドーピング反応の指標としては赤外吸収スペクトルにおける1150cm-1に現れるピーク強度を用いた. 結果は反応が2段階で生じることを示しているようである. すなわち, 最初はイミンを保護しているある種の反応障害を一定の水素イオン濃度および時間をかけてくぐり抜け, ついでイミンと水素イオンが熱活性的に反応する.

Conduction in Free-Standing Polyaniline Films and the Absorption Spectra.

溶剤に可溶なポリアニリン粉末を合成し, キャスティングにより平滑な自立膜を得た. 90～150℃で熱処理した試料をpH 0.5～6の硫酸水溶液に浸漬しその導電率を測定した. pH値が低いほど, また熱処理温度が低いほど導電率は高くなった. 試料の導電率は赤外吸収スペクトルの高波数側に生じるバックグラウンドピークと正確に対応しており, 赤外吸収スペクトルの測定から導電率が評価できることがわかった.

Gas Permeability of Free-Standing Polyaniline Films after Thermal Aging.

溶剤に可溶なポリアニリン粉末を合成し, キャスティシグにより平滑な自立膜を得た. 気体透過測定用セルに設置し, 90～130℃で熱処理しつつ各種の無機ガスを用いて透過率を測定し, 気体分離係数を評価した. 熱処理は分子間の束縛を強め, 気体分離係数の増加, 透過率, 活性化エネルギー低下の原因となることがわかった.