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Ka-Band Equipment for KOREASAT-3
Suzuki, Shinji,Ishida, Yuji,Sakaki, Shinich 통신위성우주산업연구회 2000 Joint Conference on Satellite Communications Vol.2000 No.-
NEC Corporation developed and supplied Ka-Band Equipment (IFA, C-SW, Ka-LNA, Hybrid, CH-AMP) for KOREASAT-3. The Ka-LNA has the performance of 2.1dB noise figure and 34dB gain using NE272 GaAs HEMT Transistors at 30GHz band. The CH-AMP is a 20GHz band channel amplifier and has the two selectable operation modes of FGM (Fixed Gain Mode) and ALC (Auto Level Control mode). The IFA (Input Filter Assembly) consists of 30GHz waveguide band pass filter and test coupler. The WG-SW is a 30GHz DP-DT waveguide switch. The Hybrid is a 20GHz 3dB directional coupler. The detail design and the test results of the Ka-band Units for KOREASAT-3 are described in the full paper.
Taro Suzuki,Yoshiharu Amano,Jun-ichi Takiguchi,Takumi Hashizume,Shinji Suzuki,Atsushi Yamaba 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
This paper describes a low-cost and flexible vegetation monitoring system and compares it with traditional remote sensing systems usch as airplanes and staellites. We have developed a small unmanned aerial vehicle(UAV) equipped with visible and infrared cameras for vegetation obsevation. This system can automatically generate widespread high-resolution mosaic image and calculate the vegetation index from the multiple aerial images collected by an autonomous flight of the UAV. We performed monitoring experiments at Yawata moor in Hiroshima Prefectrue. From the experimental results, we conclued that the small UAV system was effective and useful for carrying out low-cost and flexible vegetation monitoring.
State Estimation and Modeling of a Model Helicopter
Miles Colman,Shinji Suzuki 한국항공우주학회 2008 한국항공우주학회 학술발표회 논문집 Vol.- No.-
This paper presents simulation results for vehicle state estimation using the Extended Kalman Filter (EKF) to combine high-frequency high-drift inertial sensor data with zero-drifty noisy low-frequency heading, position and velocity information. The filter is outlined. The EKF also estimates gyro and accelerometer biases of an inertial measurement unit (IMU). which measures 3-axis acceleration and 3-axis angular velocities. Attitude is maintained in the unit quaternion representation to provide a singularity-free heading estimate at extreme attitudes. The attitude error is maintained in Gibbs vector form. allowing the use of 6 states for attitude error and gyro bias. The EKF fuses the IMU data with bias-free noisy position and velocity information from a GPS receiver, and Euler angles measured by a 3-axis compass. Comparison is made between results from straightforward implementation of the EKF. and an EKF implemented using both first-order state transitions and an Upper Diagonal-factored form of the covariance matrix update. We plan to present modeled and actual flight paths of the helicopter at the conference. The model used was originally used by V. Gavrilets for a heavier gas-powered helicopter.
Magnetostatic Spin Wave in a Very Thin CoFeB Film Grown on an Amorphous FeZr Buffer Layer
김동석,Kohei Nawaoka,Shinji Miwa,박승영,Yoichi Shiota,유천열,조재훈,이병찬,Yoshishige Suzuki,이긍원 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.5
The transmission of a magnetostatic spin wave in a very thin CoFeB film (2.3 nm) grown on an amorphous paramagnetic FeZr layer was demonstrated for the first time by using an antenna method with coplanar waveguides. The attenuation length, determined by using the difference in intensities due to a change in the distance between the antennas, was estimated to be 0.7 μm. We discuss why we are able to observe spin-wave propagation in such a thin magnetic layer, taking the low damping constant ( = 0.0027) of the CoFeB films grown on the amorphous FeZr layer and the estimated large group velocity in the CoFeB films into account.
Sawada Yuta,Takahashi Shinji,Terai Hidetomi,Kato Minori,Toyoda Hiromitsu,Suzuki Akinobu,Tamai Koji,Yabu Akito,Iwamae Masayoshi,Nakamura Hiroaki 대한척추외과학회 2024 Asian Spine Journal Vol.18 No.1
Study Design: Level 3 retrospective cohort case-control study.Purpose: This study aimed to investigate the risk factors for distal junctional kyphosis (DJK) caused by osteoporotic vertebral fractures following spinal reconstruction surgery, with a focus on the sagittal stable vertebra.Overview of Literature: Despite the rarity of reports on DJK in this setting, DJK was reported to reduce when the lower instrumented vertebra (LIV) was extended to the sagittal stable vertebra in the posterior corrective fixation for Scheuermann’s disease.Methods: This study included 46 patients who underwent spinal reconstruction surgery for thoracolumbar osteoporotic vertebral fractures and kyphosis and were followed up for 1 year postoperatively. DJK was defined as an advanced kyphosis angle >10° between the LIV and one lower vertebra. The patients were divided into groups with and without DJK. The risk factors of the two groups, such as patient background, surgery-related factors, radiographic parameters, and clinical outcomes, were analyzed.Results: The DJK and non-DJK groups included 14 and 32 patients, respectively, without significant differences in patient background. Those with instability in the distal adjacent LIV disc had a significantly higher risk of DJK occurrence (28.6% vs. 3.2%, <i>p</i>=0.027). DJK occurrence significantly increased in those with the sagittal stable vertebra not included in the fixation range (57.1% vs. 18.8%, <i>p</i>=0.020). Other preoperative radiographic parameters were not significantly different. Instability in the distal adjacent LIV disc (adjusted odds ratio, 14.50; <i>p</i>=0.029) and the exclusion of the sagittal stable vertebra from the fixation range (adjusted odds ratio, 5.29; <i>p</i>=0.020) were significant risk factors for DJK occurrence.Conclusions: Regarding spinal reconstruction surgery in patients with osteoporotic vertebral fractures, instability in the distal adjacent LIV disc and the exclusion of the sagittal stable vertebra from the fixation range were risk factors for DJK occurrence in the short term.
Spin-wave eigenmodes in single disk-shaped FeB nanomagnet
Cho, Jaehun,Miwa, Shinji,Yakushiji, Kay,Tamaru, Shingo,Kubota, Hitoshi,Fukushima, Akio,Fujimoto, Satoshi,Tamura, Eiiti,You, Chun-Yeol,Yuasa, Shinji,Suzuki, Yoshishige American Physical Society 2016 Physical Review B Vol.94 No.18
<P>Spin-wave eigenmodes in a disk-shaped FeB nanomagnet were investigated using magnetic tunnel junctions with a FeB magnetic layer and MgO barrier. Noise spectrum measurements for a perpendicularly magnetized junction of 120 nm in diameter showed thermal excitation of distinct spin-wave modes. The measured spectra were compared with analytical calculations and numerical simulations. As a result, the observed modes were classified as spin-wave eigenmodes with various nodal circles and nodal diameter modes by taking into account splitting between directional spin-wave modes originating from dynamic dipolar interaction instead of Dzyaloshinskii-Moriya interaction. These results provide a fundamental understanding of spin dynamics in nanosize spintronic devices.</P>
Yuji Matsuoka,Kenji Endo,Hidekazu Suzuki,Yasunobu Sawaji,Hirosuke Nishimura,Taichiro Takamatsu,Osamu Kojima,Kazuma Murata,Takeshi Seki,Shinji Horie,Takamitsu Konishi,Kengo Yamamoto 대한척추외과학회 2018 Asian Spine Journal Vol.12 No.4
Study Design: Retrospective study. Purpose: To investigate the relationship between preoperative total spinal sagittal alignment and the early onset of adjacent segment degeneration (ASD) after single-level posterior lumbar interbody fusion (PLIF) in patients with normal sagittal spinal alignment. Overview of Literature: Postoperative early-onset ASD is one of the complications after L4–L5 PLIF, a common surgical procedure for lumbar degenerative disease in patents without severe sagittal imbalance. A better understanding of the preoperative characteristics of total spinal sagittal alignment associated with early-onset ASD could help prevent the condition. Methods: The study included 70 consecutive patients diagnosed with lumbar degenerative disease who underwent single-level L4–L5 PLIF between 2011 and 2015. They were divided into two groups based on the radiographic progression of L3–L4 degeneration after 1-year follow-up: the ASD and the non-ASD (NASD) group. The following radiographic parameters were preoperatively and postoperatively measured: sagittal vertebral axis (SVA), thoracic kyphosis (TK), lumbar lordosis, pelvic tilt, and pelvic incidence (PI). Results: Eight of the 70 patients (11%) experienced ASD after PLIF (three males and five females; age, 64.4±7.7 years). The NASD group comprised 20 males and 42 females (age, 67.7±9.3 years). Six patients of the ASD group showed decreased L3–L4 disc height, one had L3–L4 local kyphosis, and one showed both changes. Preoperative SVA, PI, and TK were significantly smaller in the ASD group than in the NASD group (p<0.05). Conclusions: A preoperative small SVA and TK with small PI were the characteristic alignments for the risk of early-onset ASD in patients without preoperative severe sagittal spinal imbalance undergoing L4–L5 single-level PLIF.