著者

Kita Yuki Yoshida Shinichi Hosoi Takuji Shimura Takayoshi Shiraishi Kenji Nara Yasuo Yamada Keisaku Watanabe Heiji

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.94, no.12, pp.122905, 2009-03

被引用文献数

8 8

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Change in the work function (WF) of the gate electrode material caused by the contact with Hf-based high-k gate dielectrics was investigated by means of the flat-band voltage (Vfb) shift in capacitance-voltage curves, and the interface dipole, which modifies the WF, was characterized by x-ray photoelectron spectroscopy. We observed a negative Vfb shift and corresponding interface dipole, which suggest the formation of oxygen vacancy (VO) in the Hf-based oxides. In contrast, we observed an opposite (positive) Vfb shift and interface dipole when Au electrodes were formed on cleaned Hf-based dielectrics. This indicates that Au–Hf bond hybridization at the Au/HfSiON interface also causes effective WF modulation, as theoretically predicted by Shiraishi et al. (Tech. - Dig. Int. Electron Devices Meet. 2005, 43).

著者

Yamori Yukio Nakanishi Akifumi Kihara Masahiro Horie Ryoichi Ikeda Katsumi Nara Yasuo Ooshima Akira

出版者

International Heart Journal Association

雑誌

Japanese Heart Journal (ISSN:00214868)

巻号頁・発行日

vol.21, no.4, pp.575-575, 1980

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In the present study, it became clear that β-blocker (propranorol) had effectively improved rCBF in adult SHRSP with sever hypertension in which rCBF was significantly lower than control WKY. Yamori and Horie's previous studies clarified the BP reduction in SHRSP with severe hypertension increased rCBF and prevented the development of cerebrovascular lesions (STROKE 8: 456, 1977). It is noteworthy that β-blocker, without reducing BP significantly in SHRSP with severe hypertension, increases rCBF significantly. Because of the high frequency of pulse rate over 400/min in conscious rats, blood flow in cerebral arteries near recurrent branchings is regarded as being nearly similar to steady flow. Since our previous hemorheological study demonstrated that pulsatile flow increased flow into recurrent branches and that the effect of pulsation was augmented with the increased pulse pressure (Niimi et al: JAP HEART J 20: 681, 1979), it is theoretically considered that β-blocker, which reduces heart rate without affecting BP and thereby increases pulse pressure, favourably increases the reduced blood flow into recurrent arteries especially under severe hypertension. The present experiment substantiated this hypothesis and suggested that β-blocker, even without reducing blood pressure markedly, would be useful for preventing cerebrovascular lesions caused by hypoxia due to reduced rCBF in the predilection sites of stroke fed by recurrent arteries.