マスターズ女性長距離ランナーの呼吸循環機能に及ぼす年齢及び閉経の影響

This study sought to determine whether the ability to cardiorespiratory endurance is affects by age and menopausal status. Subjects were forty-two trained middle-aged women endurance runners (average training history=11.9±5.3 yr.) from ages of 33 to 68 yr. (average age=51.0±8.8 yr.) were tested on treadmill to examine physiological responses (Vo_2max and Vo_2 at ventilation threshold). Although 1) Vo_2max and Vo_2 at ventilation threshold was lower with age. The younger runners group (-39 and 40-49 yr.) had significantly higher Vo_2max than other two age group (50-59 and 60- yr.). 2) Maximal heart rate did not differ across age group, but HR at ventilation threshold was lower in age over sixty group. 3) Menopausal status in middle-aged women distance runners were not significantly different on any exercise physiological variable when with age. 4) A decrease in Vo_2max of 0.45ml・min ^^・kg^・yr. was determined. These findings suggested that the ability alter cardiorespiratory endurance (Vo_2max) in middle-age women runners is effect of age, but not of menopausal status

Humidity-dependent stability of amorphous germanium nitrides fabricated by plasma nitridation

Katsuhiro Kutsuki, Gaku Okamoto, Takuji Hosoi, Takayoshi Shimura and Heiji Watanabe, "Humidity-dependent stability of amorphous germanium nitrides fabricated by plasma nitridation", Appl. Phys. Lett. 91, 163501 (2007) https://doi.org/10.1063/1.2799260

Germanium oxynitride gate dielectrics formed by plasma nitridation of ultrathin thermal oxides on Ge(100)

Germanium oxynitride (GeON) gate dielectrics with surface nitrogen-rich layers were fabricated by plasma nitridation of thermally grown oxides (GeO_2) on Ge(100). Insulating features of ultrathin GeO_2 layers of around 2-nm-thick were found to improve with plasma treatment, in which leakage current was drastically reduced to over four orders of magnitude. Consequently, Au/GeON/Ge capacitors of an equivalent oxide thickness down to 1.7 nm were achieved while keeping sufficient leakage reduction merit. The minimum interface state density values of GeON/Ge structures as low as 3×10^{11} cm^{-2} eV^{-1} were obtained for both the lower and upper halves of the bandgap without any postnitridation treatments. These results were discussed based on the effects of plasma nitridation on a degraded GeO_2 surface for recovering its electrical properties by creating stable nitride layers.Katsuhiro Kutsuki, Gaku Okamoto, Takuji Hosoi, Takayoshi Shimura and Heiji Watanabe, "Germanium oxynitride gate dielectrics formed by plasma nitridation of ultrathin thermal oxides on Ge(100)", Appl. Phys. Lett. 95, 022102 (2009) https://doi.org/10.1063/1.3171938

Origin of flatband voltage shift and unusual minority carrier generation in thermally grown GeO2/Ge metal-oxide-semiconductor devices

Takuji Hosoi, Katsuhiro Kutsuki, Gaku Okamoto, Marina Saito, Takayoshi Shimura and Heiji Watanabe, "Origin of flatband voltage shift and unusual minority carrier generation in thermally grown GeO2/Ge metal-oxide-semiconductor devices", Appl. Phys. Lett. 94, 202112 (2009) https://doi.org/10.1063/1.3143627

Insight into unusual impurity absorbability of GeO2 in GeO2/Ge stacks

Adsorbed species and its diffusion behaviors in GeO_2/Ge stacks, which are future alternative metal-oxide-semiconductor (MOS) materials, have been investigated using various physical analyses. We clarified that GeO_2 rapidly absorbs moisture in air just after its exposure. After the absorbed moisture in GeO_2 reaches a certain limit, the GeO_2 starts to absorb some organic molecules, which is accompanied by a structural change in GeO_2 to form a partial carbonate or hydroxide. We also found that the hydrogen distribution in GeO_2 shows intrinsic characteristics, indicative of different diffusion behaviors at the surface and at the GeO_2/Ge interface. Because the impurity absorbability of GeO_2 has a great influence on the electrical properties in Ge-MOS devices, these results provide valuable information in realizing high quality GeO_2/Ge stacks for the actual use of Ge-MOS technologies.Shingo Ogawa, Taichi Suda, Takashi Yamamoto, Katsuhiro Kutsuki, Iori Hideshima, Takuji Hosoi, Takayoshi Shimura and Heiji Watanabe, "Insight into unusual impurity absorbability of GeO_2 in GeO_2/Ge stacks", Appl. Phys. Lett. 99, 142101 (2011), https://doi.org/10.1063/1.3644393