http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Negative Dynamic Resistance and RF Amplification in Magnetic Tunnel Junctions
Hiroyuki Tomita,Hiroki Maehara,Takayuki Nozaki,Yoshishige Suzuki 한국자기학회 2011 Journal of Magnetics Vol.16 No.2
We report on a numerical calculation study of two new functional properties in magnetic tunnel junctions (MTJs), negative dynamic resistance and RF amplification. The magnetic dynamics in a conventional CoFeB/MgO/CoFeB MTJ with in-plane magnetization was investigated using a macro-spin model simulation. To examine the influence of thermal fluctuations, random external magnetic fields were also included. Using a voltage controlled bias circuit, the negative dynamic resistance was obtained from time averaged Ⅰ-Ⅴ characteristics at both 0 K and 300 K under appropriate external magnetic fields and bias voltages. Using this negative dynamic resistance property, we demonstrated RF amplification with a 100 ㎒ high frequency signal. Sizable RF amplification gain was observed without thermal fluctuation. However, at 300 K, the RF signal was not amplified because low frequency magnetization dynamics were dominant.
Masaya Kawaguchi,Hiroki Kato,Hiroyuki Tomita,Akira Hara,Natsuko Suzui,Tatsuhiko Miyazaki,Kanako Matsuyama,Mariko Seishima,Masayuki Matsuo 대한영상의학회 2020 Korean Journal of Radiology Vol.21 No.3
Objective: This study aimed to evaluate the efficacy of magnetic resonance (MR) imaging in differentiating between cutaneous basal cell carcinoma (cBCC) and cutaneous squamous cell carcinoma (cSCC) in the head and neck region. Materials and Methods: Among patients with cutaneous head and neck cancers, 14 with primary cBCCs and 15 with primary cSCCs with a histologic tumor height of ≥ 4 mm underwent MR examinations; the findings were then examined for correlations. Results: cBCCs (71%) occurred more frequently on the nose than cSCCs (13%) (p < 0.01). The maximum diameter (23.5 ± 7.2 mm vs. 12.7 ± 4.5 mm; p < 0.01) and diameter-to-height ratio (2.8 ± 0.9 vs. 1.7 ± 0.4; p < 0.01) were significantly greater in cSCCs than in cBCCs. Superficial ulcer formation (67% vs. 21%; p < 0.05), protrusion into the subcutaneous tissue (60% vs. 21%; p < 0.05), ill-demarcated deep tumor margins (60% vs. 7%; p < 0.01), and peritumoral fat stranding (93% vs. 7%; p < 0.01) were more frequently observed in cSCCs than in cBCCs. Intratumoral T2-hyperintense foci (57% vs. 13%; p < 0.05) were more frequently observed in cBCCs than in cSCCs. Conclusion: cBCCs predominantly occurred on the nose with intratumoral T2-hyperintense foci, whereas cSCCs predominantly exhibited a flattened configuration, superficial ulcer formation, protrusion into the subcutaneous tissue, ill-demarcated deep tumor margin, and peritumoral fat stranding.
( Toshihiko Hata ),( Ken Ueda ),( Hiroshi Maruyama ),( Toshiki Takaya ),( Hiroshi Kuraishi ),( Kenji Maeda ),( Hiroki Tomita ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1
Background: In super acute phase after the Great East Japan Earthquake (11 March 2011), Disaster medical association team (DMAT) consisted of emergency physicians acted in disaster areas in the East Coast of Japan. On the other hand, these areas needed chronic care support by general physicians because of the enormous destructions of the medical facilities by the tsunami. So then, the Japanese Red Cross Society had sent disaster emergency outpatient assistance doctors to Isinomaki Red Cross Hospital, was intact because it was moved away from the Pacifi c Ocean three years ago. Methods: Determination of specialism by direct hearing and information from home page of each Red Cross Hospitals. Results: Cumulative 81 medical doctors were 38 internal medicine physicians, trainees 15, emergency physicians 12, surgeon 6, pediatrician 3, orthopedic surgeon 3, anesthesiologist 2, obstetrician 2, from April to August 2011. At fi rst 6 dispatched doctors were resident and did emergency outpatient work in Ishinomaki Red Cross Hospital for 6 days and dipatched. A lot of Cases of pneumonia and bronchial asthma due to debris and rubble by Tsunami were seen. All dispatch doctors corresponded to primary surgery including fractures and trauma, pediatric diseases, and posttraumatic stress disorder due to earthquake itself, tsunami damage, and radiation problem of Fukushima. Conclusions: The role of general physicians is very important in chronic phase of disaster medical assistance. Medical facilities in the area with many earthquakes should be moved apart from the sea in order to avoid the damage of tsunami.