Challenge to the synthesis of α′′-(Fe, Co)16N2 nanoparticles obtained by hydrogen reduction and subsequent nitrogenation starting from α-(Fe, Co)OOH

The α′′-Fe16N2 has attracted much interest as a candidate for semi-hard magnetic materials. As reported coercivity of α′′-Fe16N2 nanoparticles so far were not high, it is necessary to improve magnetocrystalline anisotropy of α′′-phase to be used practically. Since theoretical calculation suggests a possibility of the improvement of magnetocrystalline anisotropy by substituting of Fe with Co, we challenged to make α′′-(Fe1-xCox)16N2 nanoparticles by hydrogen reduction of α-(Fe1-xCox)OOH as a starting material changing X from 0 to 0.1. We were able to produce α-(Fe1-xCox) nanoparticles through (Fe0.98Co0.02)OOH, and (Fe0.95Co0.05)OOH and (Fe0.95Co0.05)2O3. Sintering occurred during reduction and crystallite diameter D increased with increasing reduction temperature. α′′-(Fe1-xCox)16N2 phase containing α-(Fe,Co) nanoparticles were obtained only at reduction of 340 °C for 4 h and nitridation of 170 °C for 5 h for X = 0.02. It has been revealed that α′′-(Fe1-xCox)16N2 or α′′-Fe16N2 could be formed below D = 50 nm of α-(Fe,Co) or α-Fe. And containing Co make it more difficult to produce α′′-phase. It can be said that the formation of α′′-(Fe1-xCox)16N2 is subject to a limit of D and Co content. Long time nitridation is only way to increase the formation yield of α′′-(Fe1-xCox)16N. High Hc = 2000 Oe was obtained for α′′-(Fe0.98Co0.02)16N2 by changing nitridation time 10 hours from 5 hours. Further long nitradation is expected to increase in Hc of α′′-(Fe0.98Co0.02)16N2

心機能とβ-アドレナリン受容体情報伝達

雑誌掲載

肺高血圧症 最近の進歩

雑誌掲載版肺高血圧症のうち一次性肺高血圧症(原発性肺高血圧症)は原因不明の疾患群を総称しているが,二次性肺高血圧症の多くは,外的刺激によって内皮細胞が障害をうけ,種々の応答を繰り返して肺血管リモデリングが進展するため,肺高血圧が発症し持続する.その結果,肺血管インピーダンスの増加をきたし,右心負荷から右心肥大・右心不全という一連の病態を引き起こす.プロスタサイクリンは肺動脈圧を下げ,心拍出量をあげ,体酸素供給を増やし,肺血管リモデリングを改善する.NOは,特異的に肺血管床のみに作用して,肺動脈圧を下げる急性効果はあるが,慢性効果については投与法も含め検討されてい

Mobile phone user authentication with grip gestures using pressure sensors

Purpose– User authentication is generally used to protect personal information such as phone numbers, photos and account information stored in a mobile device by limiting the user to a specific person, e.g. the owner of the device. Authentication methods with password, PIN, face recognition and fingerprint identification have been widely used; however, these methods have problems of difficulty in one-handed operation, vulnerability to shoulder hacking and illegal access using fingerprint with either super glue or facial portrait. From viewpoints of usability and safety, strong and uncomplicated method is required.Design/methodology/approach– In this paper, a user authentication method is proposed based on grip gestures using pressure sensors mounted on the lateral and back sides of a mobile phone. Grip gesture is an operation of grasping a mobile phone, which is assumed to be done instead of conventional unlock procedure. Grip gesture can be performed with one hand. Moreover, it is hard to imitate grip gestures, as finger movements and grip force during a grip gesture are hardly seen by the others.Findings– The feature values of grip force are experimentally investigated and the proposed method from viewpoint of error rate is evaluated. From the result, this method achieved 0.02 of equal error rate, which is equivalent to face recognition.Originality/value– Many researches using pressure sensors to recognize grip pattern have been proposed thus far; however, the conventional works just recognize grip patterns and do not identify users, or need long pressure data to finish confident authentication. This proposed method authenticates users with a short grip gesture