가변구조 제어시스템의 Luenberger Observer에 관한 연구

탁한호,이형기,박양수,권세현 釜山工業大學校 1991 論文集 Vol.33 No.-

This paper presents an analysis of the stste observer-based robust speed control of a self-controlled synchonous motor (SCSM). A Variable structure control (VSC) technique is utilized to achieve robust (paramater-insensitive) characteristics. The speed and acceleration signals required for the implementation of the variable structure speed control (VSSC) are dynamically estimated with stste observer. One kind observer-the Luenberger full order observer-air explored in this paper. The results obtained that Luenverger observers do estimate the system ststes accurately when the system parameters vary. The design methods and the simulation results presented demonstrable the potential of the proposed scheme.

자연과학적 데이터를 활용한 풍납토성 백제토기의 분류 방안 연구

문은정 ( Eun Jung Moon ),강희준 ( Hee Jun Kang ),한민수 ( Min Su Han ),이한형 ( Han Hyoung Lee ) 백제학회 2011 백제학보 Vol.0 No.5

본 연구는 풍납토성 출토 백제토기를 대상으로 현장에서 소성온도에 따라 토기를 분류할 수 있는 외형관찰 기준을 마련하는데 자연과학적 데이터를 활용하고자 하는 연구이다. 소성온도는 토기의 경도, 밀도 풍을 포함한 다양한 물리화학적 특성에 영향을 미친다. 이 중 현장에서 측정이 가능하고 유용한 것이 경도이다. 그러므로 우리나라의 발굴현장에서 적용하고 있는 경도 측정기준을 적용하여 토기를 분류하고, 자연과학적 분석을 통하여 이들 토기의 마이크로비커스 경도, 밀도, 흡수율, 조직의 유리질화도, 광물학적 특성 등을 측정하여 현장에서 적용하는 경도분류 기준과의 상관관계를 비교연구하였다. 그 결과, 발굴현장에서 동전의 긁힘에 의해 주로 행해지던 연질과 경질의 이분법적 분류는 연질과 연경질, 경질의 세 단계로 세분됨을 알 수 있었다. 소성 온도 추정 결과, 연질은 1,000˚C 이하, 연경질은 1,000~1,100˚C, 경질은 1,200˚C 이상에서 소성되었을 것으로 판단된다. 한편, 3단계로 분류되는 토기들의 각 단계별 외형적 공통점을 추출하여 자연과학적인 정밀분석 없이 육안관찰만으로 토기를 3단계로 분류할 수 있는 관찰기준의 제시를 시도하였다. 이러한 기준은 파괴분석을 하지 않고도 토기의 외형적 특징을 이용하여 토기의 대략적인 물성과 소성온도 추정을 가능하게 할 것으로 기대된다. 단, 이러한 기준은 풍납토성에서 출토된 한성백제시기의 토기 중에서 배류와 호류 등 색상이 단조로운 제한된 기종을 중심으로 한 결과라는 한계를 가진다. 따라서 추가적으로 여러 기종의 다양한 색상을 가진 토기들을 대상으로 풍납토성 출토 토기의 경도별 분류가 가능하도록 수정·보완하는 연구를 진행할 예정이다. Observation methods of appearance were studied to establish a systemized classification criteria according to the firing temperatures of excavated earthenware from the Pung-Nap Mud Castle. A firing temperature has an impact on various physical and chemical properties including hardness and density of earthenware. Of all the properties, hardness can be measured in situ. Therefore, the earthenware were categorized according to the measurement method of hardness which can be applied and useful method for archaeological sites. In addition, the correlation between the measurement method and micro Vickers hardness, absorptance, degree of vitrescence and mineralogical properties of the earthenware were studied by means of a natural scientific analysis. The result suggests that the dichotomous way of classification based on a scratching method determining whether it is hard or soft should be categorized into three stages; soft, soft/hard and hard. According to the presumption of the firing temperature, it is believed that the earthenware were fired at below 1,000℃, 1,000~1,100℃ and 1,200℃ respectively. The systemized observation method was proposed to enable the earthenware to be categorized into three stages using visual observation without a detailed scientific analysis. The method will make it possible to estimate roughly the physical properties and firing temperature of the earthenware with only visual observation. However, it has limits as it was established focusing on certain types such as Cups and Jars among the Han-Sung Baek-Je earthenware. Therefore, a further study is planned to be carried out on various objects excavated from Pung-Nap Mud Castle in order to enable categorization on the basis of hardness of the earthenware.

Hardening behavior and highly enhanced mechanical quality factor in (K_0.5Na_0.5)NbO₃–based ceramics

Han, Hyoung-Su,Koruza, Jurij,Patterson, Eric A.,Schultheiß, Jan,Erdem, Emre,Jo, Wook,Lee, Jae-Shin,Rö,del, Jü,rgen Elsevier Science Publishers 2017 Journal of the European Ceramic Society Vol. No.

<P><B>Abstract</B></P> <P>This paper relates the microstructure, crystallographic structure, ferroelectric, and piezoelectric properties of (K<SUB>0.5</SUB>Na<SUB>0.5</SUB>)NbO<SUB>3</SUB> (KNN) ceramics modified with 0.38mol% K<SUB>5.4</SUB>Cu<SUB>1.3</SUB>Ta<SUB>10</SUB>O<SUB>29</SUB> (KCT) and different amounts of CuO. Results revealed that the addition of KCT and CuO were effective in enhancing the sinterability of KNN. The internal bias field (<I>E</I> <SUB>ib</SUB>) increased from 0.3kV/mm to 0.58kV/mm at 0.5mol% CuO–added KNN+KCT ceramics. The increase of <I>E</I> <SUB>ib</SUB> corresponds very well with the observed increase of the mechanical quality factor (<I>Q</I> <SUB>m</SUB>) from 112 to 2665 for 0.5mol% CuO. Besides, addition of 0.5mol% CuO to KNN+KCT resulted in a large increase of the EPR signal, which is related to the increased amount Cu<SUP>2+</SUP> and a corresponding increase of the concentration of defect dipoles. This result is in good agreement with the increased <I>E</I> <SUB>ib</SUB> and the resulting hardening behavior.</P>

Incipient piezoelectrics and electrostriction behavior in Sn-doped Bi_1/2(Na_0.82K_0.18)_1/2TiO₃ lead-free ceramics

Han, Hyoung-Su,Jo, Wook,Kang, Jin-Kyu,Ahn, Chang-Won,Won Kim, Ill,Ahn, Kyoung-Kwan,Lee, Jae-Shin American Institute of Physics 2013 JOURNAL OF APPLIED PHYSICS - Vol.113 No.15

Low-Firing Pb(Zr,Ti)O₃-Based Multilayer Ceramic Actuators Using Ag Inner Electrode

Han, Hyoung-Su,Park, Eon-Cheol,Lee, Jae-Shin,Yoon, Jong-Il,Ahn, Kyoung-Kwan The Korean Institute of Electrical and Electronic 2011 Transactions on Electrical and Electronic Material Vol.12 No.6

We investigated the low firing of $Li_2CO_3$ added $0.2Pb(Mg_{1/3}Nb_{2/3})O_3$ - 0.3Pb($Fe_{1/2}Nb_{1/2}$) - $0.5Pb(Zr_{0.475}Ti_{0.525})O_3$ (PMN-PFN-PZT) ceramics and multilayer actuators (MLAs) using Ag inner electrodes. It was found that 0.1 wt% $Li_2CO_3$ was quite effective in lowering the sintering temperature of PMN-PFN-PZT ceramics from $1,100^{\circ}C$ down to $900^{\circ}C$ without deteriorating their piezoelectric ceramics ($d_{33}$ = 425 pC/N and $k_p$ = 61.9%). However, excess $Li_2CO_3$ up to 0.3 wt% brings about unwanted problems such as the formation of a $LiPbO_2$ secondary phase and subsequent degradation in the piezoelectric properties. Using 0.1 wt% $Li_2CO_3$ added PMN-PFN-PZT ceramics, MLAs with Ag inner electrodes were successfully fabricated, resulting in a normalized strain of 580 pm/V at an electric field of 1.5 kV/mm.

A 14-Day Repeated Dose Toxicity of Polygalae Radix Administered by Oral Gavage in F344 Rats

Hyoung-Yun Han,SooNam Kim,Young-Su Yang,Mi-Jin Yang,Su-Cheol Han,Shin-Woo Cha,Byung-Sun Min 한국실험동물학회 2014 한국실험동물학회 학술발표대회 논문집 Vol.2014 No.8

Effect of Nb Doping on the Dielectric and Strain Properties of Lead-free 0.94(Bi_1/2Na_1/2)TiO₃-0.06BaTiO₃ Ceramics

Han, Hyoung-Su,Hong, In-Ki,Kong, Young-Min,Lee, Jae-Shin,Jo, Wook The Korean Ceramic Society 2016 한국세라믹학회지 Vol.53 No.2

$(Bi_{1/2}Na_{1/2})_{0.94}Ba_{0.06}(Ti_{1-x}Nb_x)O_3$ (BNBTxNb) ceramics were investigated in terms of the crystal structure as well as the ferroelectric, dielectric, and piezoelectric properties. While little change was observed in the microstructure except for a slight decrease in the average grain size, a significant change was noticed in the temperature dependence of dielectric and piezoelectric properties. It was shown that the property changes are closely related to the downward shift in the position of the ferroelectric-to-relaxor transition temperature with increasing amount of Nb doping. A special emphasis is put on the fact that Nb doping is so effective at decreasing the ferroelectric-to-relaxor transition temperature that even at no more than 2 at.% Nb addition, the transition temperature was already brought down slightly below room temperature, resulting in the birth of a large strain at 0.46 %, equivalent to $S_{max}/E_{max}=767pm/V$.

비스무스계 무연 압전세라믹스의 저전계 변형특성 향상을 위한 세라믹/세라믹 복합소재 기술

한형수(Hyoung-Su Han),즈엉 짱 안(Trang An Duong),안창원(Chang Won Ahn),조욱(Wook Jo),이재신(Jae-Shin Lee) 한국세라믹학회 2020 세라미스트 Vol.23 No.1

Abnormally large electromechanical strain properties have been reported in bismuth-based piezoelectric ceramics, which cast a promise for replacing the market-dominating PZT-based piezoelectric ceramics in actuator applications. In spite of these large strains in bismuth-based piezoelectric ceramics, there still remains a critical issue for its safe transfer to practical applications, representatively, a relatively high operating field required to obtain the large strain properties. To overcome the challenge, much attention has been paid to so-called 0-3(or 3-0) type ceramic/ceramic composite approach to better tailoring the strain properties of bismuth-based piezoelectric ceramics. The approach turns out to be highly effective, leading to a drastic decrease in the operating electric field for these materials. Besides, both extensive and intensive search for the related mechanism revealed that the reduction in the operating electric field is largely due to the contribution from polarization coupling or strain coupling model between two different ceramics. This article reviews the status of the art in the development of novel ceramic/ceramic composites to make large incipient piezostrains in bismuth-based lead-free piezoelectric ceramics practical.

선형 가변 차동 변압기를 이용한 강유전 세라믹의 전기장 인가에 따른 변형 측정

한형수 ( Hyoung-su Han ),안창원 ( Chang Won Ahn ) 한국전기전자재료학회 2024 전기전자재료학회논문지 Vol.37 No.2

강유전체, 압전체 및 전왜 재료의 전기-기계적 반응의 기본 원리를 이해하기 위해 전기장 인가에 따른 변형 측정법은 널리 사용되고 있다. 특히, 전기 자극에 반응하는 압전 재료의 변형 특성을 이해하는 것은 압전 액츄에이터, 음향 장치, 초음파발생기와 같은 부품을 연구하고 개발하는 데 중요하다. 이 튜토리얼 논문에서는 다양한 산업 분야에서 널리 사용되는 변위 측정 장치인 선형 가변 차동 변환기(linear variable differential transducer, LVDT)의 구성 요소와 작동 원리를 소개한다. 또한 전기장을 인가하여 강유전체, 압전체 또는 전왜 재료의 변형 특성을 측정하기 위해 LVDT를 사용하는 실험 장치의 구성을 소개한다. 그리고 이 논문에는 LVDT 실험 장치를 통해 얻은 간단한 측정 결과와 분석이 포함되어 있어서 다양한 재료의 전기-기계 상호 작용 연구 방법에 대해 유용한 정보를 제공한다. The measurement of strain under an electric field has been widely employed to comprehend the fundamental principles of electro-mechanical responses in ferroelectric, piezoelectric, and electrostrictive materials. In particular, understanding the strain properties of piezoelectric materials in response to electrical stimulation is crucial for researching and developing components such as piezoelectric actuators, acoustic devices, and ultrasonic generators. This tutorial paper introduces the components and operational principles of the linear variable differential transducer (LVDT), a widely used displacement measurement device in various industries. Additionally, we present the configuration of an experimental setup using LVDT to measure the strain characteristics of ferroelectric, piezoelectric, or electrostrictive materials under the application of an electric field. This paper includes simple measurement results and analyses obtained through the LVDT experimental setup, providing valuable information on research methods for the electro-mechanical interactions of various materials.

우리나라 물리치료 수가에 관한 연구

김형수 ( Hyoung Su Kim ),심제명 ( Je Myung Shim ),박성수 ( Sung Su Park ),한진태 ( Jin Tae Han ),김은영 ( Eun Young Kim ) 대한물리의학회 2010 대한물리의학회지 Vol.5 No.2

Purpose:This study aims to figure out problems in Korea`s physical therapy, how to improve it, and the need for it by examining the nation`s physical therapy charges. Methods:This study was performed based on materials from the National Health Insurance Corporation, Korean academic theses, and domestic medical charge system. Results:The number of patients with physical therapy stood at around 17,764,428 in 2008, and then has gradually rose to 3 out of 100,000 citizens. The National Health Insurance Charge System based on relative values, which has been applied since 2001, is not desirable in that it is increasing patients` financial burden. Also, in deciding the amount of work carried out by physical therapists, their amount of input time, efforts, labor, and stress from their patients were not considered and the false relative value system has made patients pay more. Conclusion:Korean medical insurance charges and the overall system should be improved, so that physical therapists can perform specialized services of global physical therapy and service receiving patients do not incur losses.