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α-(Fe, Co)기 Nd - (Fe, Co) - B - Nb - Cu 초미세결정립합금의 자기특성에 미치는 Nd의 영향
조덕호(Duck-Ho Cho),조용수(Y. S. Cho),김택기(T. K. Kim),송민석(M. S. Song),김윤배(Y. B. Kim) 한국자기학회 1999 韓國磁氣學會誌 Vol.9 No.3
Magnetic properties and microstructure of nanocrystalline α-(Fe, Co)-based Nd-(Fe, Co)-B-Nb-Cu alloys have been investigated. Ndx(Fe_(0.9)Co_(0.1))_(90-x)B_6Nb₃Cu₁(x = 2, 3, 4, 5, 6) alloys prepared by rapid solidification process show amorphous phase except the one with x = 2. By a proper annealing, the amorphous phase in the alloy is changed to a nanocrystalline phase. It is confirmed that the nanocrystalline alloys are composed of α-(Fe, Co) and Nd₂(Fe, Co)₁₄B₁ phase. The optimally annealed Nd₃(Fe_(0.9)Co_(0.1))_(87)B_6Nb₃Cu₁ alloy shows the highest remanence of 1.55 T. The coercivity increases with the increase of Nd content. The maximum coercivity of 4.6 kOe is obtained from an optimally annealed Nd_6(Fe_(0.9)Co_(0.1))_(84)B_6Nb₃Cu₁ alloy, resulting in the maximum energy product of 10.6 MGOe.
곽대순(Dai-soon. Kwak),최광남(Kwang-Nam. Choi),김상국(Sang-Kuk. Kim),이상호(Sang-Ho. Lee),김태중(Tae-Joong. Kim),한승호(Seung-Ho. Han),오택열(T.Y. Oh) 한국정밀공학회 2005 한국정밀공학회 학술발표대회 논문집 Vol.2005 No.10월
We performed the mechanical test for obtaining properties of femoral head. Tested sample was male and 35 years old. We measured bone mineral density by dual X-ray absorption method(DEXA). Results of DEXA, he has normal condition of bone density. His BMD 1.159g/㎠ and T-Score is 1.6. Tested femurs were harvested by surgical method from donated cadaver. We made 9 specimens in femoral head, 8 specimens in neck used by diamond core drill. Then we performed compressive test in saline solution at 38 . We obtained results that elastic modulus of femoral head was 0.439㎬, neck was 0.459㎬. Compressive strength of femoral head was 7.441㎫, neck was 7.095㎫. There was no significant difference of mechanical properties between left and right femoral head & neck. Invested local properties of femoral head have more strength superior and anterior side, femoral neck has more strength in superior and inferior side but other side except for superior has more weakness along the lateral side.
강정욱(Jung-Yoog Kang),전용호(Yong-Ho Jeon) 한국전자통신학회 2019 한국전자통신학회 논문지 Vol.14 No.1
본 연구는 유리차수 미분의 수학적인 방법을 시스템의 응답을 제어하는 제어기에 적용하고자 한다. 일반적인 PID제어기의 라플라스 변환은 의 정수지수를 갖게 된다. 유리차수의 미분은 라플라스 변환에서 에 대한 유리수 지수를 갖게 된다. 따라서 이를 제어기로 구성하기 위해서는 유리수 지수에 대한 설계가 적절하지 않아 이산시간으로 변환하여 설계하는 방법을 제안한다. 이를 표준 2차 시스템에 적용하여 성능을 살펴보고, 산업현장에서 많이 사용되는 솔레노이드밸브에 적용한다. 외란 상태의 추정이 가능하도록 루엔버거 관측기를 설계하고 관측된 상태에 대하여 유리차수 제어기를 적용하여 균일하며 정밀한 제어성능을 얻을 수 있었다. 정상상태의 위치오차가 0.1 [%]이내이고, 기동시간이 약 0.3 [s]이내의 정밀하며 균일한 위치제어성능 가짐을 확인할 수 있었다. This study aims to apply the mathematical method of fractional order derivatives to the controller that controls the system response. In general, the Laplace transform of the PID controller has an exponent of the integer order of s. The derivative of the fractional order has a fractional exponent of s when it is transformed by Laplace transform. Therefore, this controller proposes a design method with the result of discrete time conversion. Because controllers with fractional exponents of s are not easy to design. This controller is applied to a standard secondary system and its performance is examined. Then, it applies to solenoid valve which is widely used in industrial field. A Luenberger‘s observer was designed to estimate the disturbance state and the observed state was applied to the fractional order controller. As a result, uniform and precise control performance was obtained. It was confirmed that the position error of the steady state is within 0.1 [%] and the rising time is within about 0.03 [s].
C.T. Hsieh,M.W. Lin,C.L. Chang,Y.C. Ho,S.Y. Chen,J. Wang,M.C. Chou,J.Y. Lin,C.H. Pai,P.H. Lin,L.C. Tai,S.H. Chen,G.Y. Tsaur,C.C. Kuo,T.Y. Chien 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.6
A general method for fabricating transient plasma structures with high-intensity laser pulses is developed to gain fine control over laser-plasma interactions. These structures have been used as programmable photonic devices in the development of laser-wakefield accelerators, soft X-ray lasers and plasma nonlinear optics driven by multi-terawatt laser pulses. Plasma ramps are used to control electron injection in laser-wakefield accelerators, plasma waveguides are used to enhance the efficiency of soft X-ray lasers by orders of magnitude and periodic plasma structures are used to achieve quasi-phase matching in relativistic harmonic generation. By scanning the interaction length with the same plasma-fabrication method, tomographic measurements are carried out to resolve the injection/acceleration process in laser-wakefield accelerators and amplification processes in X-ray lasers and relativistic harmonic generation. A theoretical analysis and a computer simulation are also carried out to provide insightful pictures of these processes. These research works show that by controlling plasma structures with optical fabrication methods, laser-plasma interaction can be engineered to expand and enrich the frontier of high-field physics.
Interference Effect betweenϕandΛ(1520)Production Channels in theγp→K+K−pReaction near Threshold
Ryu, S. Y.,Ahn, J. K.,Nakano, T.,Ahn, D. S.,Ajimura, S.,Akimune, H.,Asano, Y.,Chang, W. C.,Chen, J. Y.,Daté,, S.,Ejiri, H.,Fujimura, H.,Fujiwara, M.,Fukui, S.,Hasegawa, S.,Hicks, K.,Horie, K.,Ho American Physical Society 2016 Physical Review Letters Vol.116 No.23
<P>The phi-Lambda(1520) interference effect in the gamma p -> K(+)K(-)p reaction has been measured for the first time in the energy range from 1.673 to 2.173 GeV. The relative phases between phi and Lambda(1520) production amplitudes were obtained in the kinematic region where the two resonances overlap. The measurement results support strong constructive interference when K+K- pairs are observed at forward angles but destructive interference for proton emission at forward angles. Furthermore, the observed interference effect does not account for the root s = 2.1 GeV bump structure in forward differential cross sections for phi photoproduction. This fact suggests possible exotic structures such as a hidden-strangeness pentaquark state, a new Pomeron exchange, or rescattering processes via other hyperon states.</P>