Forced heated air vent and chlorine dioxide gas treatments to improve storability of onion (Allium cepa cv. Turbo) bulbs

학위논문 (석사)-- 서울대학교 대학원 : 식물생산과학부(원예과학전공), 2012. 2. 이승구.This study was conducted to elucidate effects of forced heated air vent on sprouting and chlorine dioxide (CD) gas on qualities of field cured onion Turbo bulbs. Forced heated air vent was conducted at 30oC for 8 days or 40oC for 4 days under the 60% relative humidity (RH), and then onion bulbs were stored at 5oC for 6 months. Skin moisture contents, weight loss, malondialdehyde (MDA), respiration rate, and sprouting were measured. CD gas was applicated on unpeeled and peeled onion bulbs, and onion skins inoculated with microorganism at the concentration of 1000, 500, or 250 ppmv for 1, 0.5, or 0.25 hour, then samples were stored at 0oC for 7 weeks. Visual appearance, weight loss, total soluble solids (TSS), pungency, firmness, total phenolic content, and reduction of the number of microorganisms were measured. Forced heated air vent treatment reduced the moisture contents of onion skins without any influence on the sprouting of onion bulbs. And application of CD gas on onion bulbs with intact skins reduced the number of microorganisms on onion surfaces without any deterioration in qualities of onion bulbs. Therefore, forced heated air vent is a postharvest process useful in the storage of onion bulbs and CD gas is a disinfectant applicable on onion bulbs for the storability.노지 건조를 마친 양파 터보를 사용하여 강압 열풍 건조가 양파의 출엽에 주는 영향과 이산화염소 가스의 처리가 양파의 품질과 미생물에 어떤 영향을 주는지 밝혀내기 위하여 본 실험을 진행하였다. 강압 열풍 건조 처리는 60%의 상대습도 하에 30oC에 8일간 또는 40oC에서 4일간 진행되었으며, 처리된 양파는 5oC의 저장고에서 6개월간 저장되었다. 저장 기간 중 양파의 껍질 수분 함량, 중량 감소, 말론다이알데하이드 함량, 호흡 속도, 출엽 속도를 측정하였다. 이산화염소 가스는 벗긴 양파, 벗기지 않은 양파, 미생물을 접종한 양파껍질에 1,000, 500, 250 ppmv의 농도로 1, 0.5, 0.25 시간 동안 처리하였으며, 처리가 끝난 양파는 0oC에 7주간 저장되었다. 저장기간 중 외관, 중량 감소, 가용성 고형물, 매운 정도, 경도, 총 페놀 함량, 미생물의 개체수 감소를 측정하였다. 실험 결과, 강압 열풍 건조 처리는 양파의 출엽에 아무런 영향을 주지 않고, 껍질의 수분 함량을 감소시켰으며, 이산화 염소의 온전한 껍질을 가진 양파에 처리는 양파의 품질에 아무런 손상을 주지 않은 채, 양파 껍질의 미생물을 감소시켰다. 따라서, 강압 열풍 건조는 양파의 저장에 있어 유용한 수확후처리 과정이고, 이산화염소 가스는 양파의 저장성 증진을 위해 처리 가능한 살균제라 할 수 있다.Maste

Patient and Caregiver Perception of Poststroke Depression

보건학과/석사[한글] 본 연구에서는 뇌졸중 환자의 우울증에 관하여 환자가 평가한 자가 우울 정도와 뇌졸중 환자를 돌보는 보호자가 평가한 환자의 우울 정도를 평가하여 그 차이를 알아보기 위하여 4개의 대학부속병원, 5개의 종합병원, 그리고 1개의 국군통합병원에서 재활 치료중인 뇌졸중 환자와 보호자 각각 116명을 대상으로 1995년 3월 13일부터 4월 13일까지 설문조사를 실시하였다. 뇌졸중 환자의 우울 정도, 환자와 보호자의 특성에 따른 환자의 우울 정도 차이, 비우울군과 우울군의 특성비교 및 우울중 발현증상의 순서를 알아본 결과는 다음과 같다 1. 116명의 뇌졸중 환자에서 43명(37%)의 환자가 우울범위에 속하였으며, 경증이 38명(33%), 중경증이 5명(4%)이며 중증의 우울증 환자는 없었다. 2. 뇌졸중 환자의 심리적 우울성향과 전체우울에 관련된 요인들은 교육정도, 치료형태, 훈련 정도, 치료 적응도, 약복용 및 기능회복이었다. 3. 뇌졸중 환자의 우울 정도는 보호자가 평가한 우울 정도보다 높게 나타났으며, 보호자가 환자의 우울 정도를 과소평가하고 있음을 보이고있었다. 4. 환자와의 관계에 따른 보호자의 평균점수 일치도에서는 배우자에서 보다 아들, 딸, 며느리가 포함된 자식에서 일치도가 더 높게 나왔다. 5. 보호자의 특성별 환자와의 평균점수 일치도에서 관련된 요인들은 보호자의 간호기간, 환자와의 동거관계, 뇌졸중 간호지식 및 건강상태였다. 6. 우울군과 비우울군의 특성 비교에서는 환자의 경우 마비부위, 용돈, 당뇨약 복용이 의의있게 차이가 있었으며, 보호자의 경우 결혼상태와 간호기간이 유의한 차이가 있었던 것 이외에 다른 차이는 없었다. 7. 뇌졸중 환자가 느끼는 우울증상의 발현 순서중 가장 점수가 높은 것은 심리적 우울성향인데 반해, 보호자가 보는 환자의 우울증 중 심하다고 느끼는 항목은 생리적 우울성향으로 환자와 보호자간에 차이가 있었다. 이러한 연구결과를 감안하여 볼 때 뇌졸중 환자의 재활치료에 임상적인 치료방법 뿐만 아니라 신경정신적인 후유증의 하나인 우울에 주는 영향을 감소할 수 있도록 가족 및 보호자의 지지체계 개념을 마련해 볼 만하다고 판단되며, 환자의 성공적 재활을 위한 적절한 치료적 중재가 있어야 하겠다. 이 연구의 제한점으로는 현재 재활치료를 받고 있는 뇌졸중 환자만을 연구대상으로 조사하였다는 점이다. 앞으로는 이 연구에서 고려하지 못한점과 제한점을 보완시키는 연구가 필요하다고 생각한다. [영문] The purpose of this study is to examine the differences between the degree of depression experienced by stroke patients and that of his/her caregivers. During the period from March 13 through April 13, 1995, 116 patients and caregivers were each presented with a questionnaire to determine the differences between the patient's severity of depression and the degree of depression experienced by the caregivers as a result of their respective depression characteristics. Furthermore, in order to determine the states of depression and nondepression, characteristics of depression were quantified by using a point system to classify the patients and their caregivers into two groups. The results are as followed: 1. Amongst the 116 stroke patients surveyed, 43 patients (37%) fell under the category defined as depression, 38 patients (33%) were defined as mild to moderate depression and 5 patients (4%) as having moderate to severe depression. However, no patient fell under the category of severe depression. 2. Factors linking the psychological state of mind and the severity of depression were the patient's level of education, type of treatment, degree of home program training, adaptability to treatment, drug intake, and functional status. 3. The levels of depression recorded by the caregivers were much lower than those recorded by the patients. This was a result of the caregiver underestimating the patient's severity of depression. 4. The level of depression experienced by the patient's son(S),daughter(S), daughter-in-law(S) were higher than that recorded by the patient's spouse. 5. The variables affecting the caregiver's recorded degree of depression were the following: care period, living with the patient, knowledge about stroke care, and the caregiver's health status. 6. Based on the characteristics categorizing the nondepressed and depressed group, the patients were most affected by the area of paralysis, pocket money and the taking of diabetic drugs. On the other hand, the caregivers were most affected by marriage status and the period of care. 7. The highest points were given to the psychological disturbances of depression for the patients and physiological disturbances of depression for the caregivers. As a result of this study, it may be concluded and recommended that stroke patients should, in addition to physical rehabilitation, be exposed to neuro-psychological treatment not only for minimizing the after-affects of stroke but also to maximize support from the caregiver and family. Thus, it is recommended that, for full and successful recovery of a stroke patient, a psychologist must be present to act as a mediator for the patient and their respective family members.restrictio

Study on Real-time Statistical Process Monitoring Using Local Outlier Factor

학위논문 (석사)-- 서울대학교 대학원 : 산업·조선공학부, 2011.2. 강석호.Maste

(The) development of Korean activities of daily living evaluation tools for persons with stroke by using Rasch analysis

재활학과/박사[한글]본 연구의 목적은 문항반응이론에 기초한 라쉬모형을 적용하여 뇌졸중 환자의 일상생활수행 평가도구를 개발하는 것이다. 연구대상자는 총 477명의 뇌졸중 환자로 입원환자 308명, 외래환자 169명이었다. 조사방법은 사전연구에서 항목의 중요도로 수집된 23개의 일상생활수행 평가항목으로 구성된 설문지를 사용하였다. 조사자료는 전국 18개 재활기관에서 작업치료사가 평가한 결과를 수집하여 Winsteps 프로그램으로 라쉬분석을 하였으며, 연구 결과는 다음과 같다.1. 입원환자에서는 3개 항목이 부적합한 항목으로 판정되었으며, 20개 항목이 적절한 항목으로 채택되었다. 뇌졸중 입원환자의 일상생활 수행능력은 -6.77~6.73 로짓으로 표시할 수 있으며, 표준화점수로 표시하기 위한 변환식은 “점수=(로짓점수+6.77)/(6.77+6.73)x100” 이었다.2. 외래환자에서는 7개 항목이 부적합한 항목으로 판정되었으며, 16개 항목이 적절한 항목으로 채택되었다. 뇌졸중 외래환자의 일상생활 수행능력은 -6.32~6.23 로짓으로 표시할 수 있으며, 표준화점수로 표시하기 위한 변환식은 “점수=(로짓점수+6.32)/(6.32+6.23)x100” 이었다.3. 입원환자와 외래환자의 일상생활 수행능력을 평가하기위한 항목을 난이도 순서에 따라 배열하였다. 입원과 외래에서 동일하게 가장 어려운 항목은 보행영역의 ‘계단 오르내리기’ 항목이었으며, 가장 쉬운 항목은 식사하기 영역의 ‘음료 마시기’항목이었다.이 연구에서 개발된 뇌졸중 환자의 일상생활수행 평가도구는 신뢰도와 타당도가 입증된 도구로 평가 및 치료의 자료로 유용하게 사용될 것으로 기대한다. [영문]This study was designed to develop the Korean Activities of Daily Living (ADL) evaluation tools for persons with stroke applying the Rasch model based on item response theory. The total subjects for this study were 477 stroke patients, 308 inpatients and 169 outpatients, at 18 different rehabilitation facilities in Korea. Questionnaires containing ADL evaluation items selected in advance with the Q-sorting method from the preexisting ADL related literatures were distributed to the subjects by mail or visit. Rasch analysis was then done by means of the Winsteps program to determine the validity and reliability of the Korean ADL evaluation tools for persons with stroke. The results were as follows :1. In case of inpatients, three items were found to be misfits and the order of item difficulty of the remaining 20 items was arranged. Stroke inpatients'' ADL ability is indicated by -6.77~6.73 logit, and the transformation formula is “score=(logit score+6.77)/(6.77+6.73)×100.”2. In case of outpatients, seven items were found to be misfits and the order of item difficulty of the remaining 16 items was arranged. Stroke outpatients'' ADL ability is indicated by -6.32~6.23 logit, and the transformation formula is “score=(logit score+6.32)/(6.32+6.23)×100.”3. In the order of difficulty of evaluation items, inpatients and outpatients responded equally. The most difficult item was “going up and down stairs,” which was one from the functional mobility domain. And the easiest item was “drinking,” which was one from the feeding domain.In conclusion, the Korean ADL evaluation tools for persons with stroke have been proven reliable and valid. Therefore they are expected to be used as effective tools for treatment planning and intervention for persons with stroke.ope

Analysis of impurities in illicit methamphetamine

학위논문(박사)--서울대학교 대학원 :약학과,2007.Docto

Characterization of B-doped Hydrogenated Amorphous Silicon Films Grown by Plasma-Enhanced Chemical-Vapor Deposition

SiH₄와 B₂H6를 반응기체로 이용하여 플라즈마 화학증착법으로 유리기판 위에 붕소를 고농도로 도핑한 비정질 실리콘 박막을 증착하였다. X선회절법, 라만산란법, 적외선분광법, 자외선 분광법 등으로 증착된 박막의 물성을 분석하였다. 기상도핑율인 [B₂H6]/[SiH₄]이 증가함에 따라 박막내 미세결정상의 체적분율과 수소량은 증가하였으며, 광학적인 에너지갭과 저항은 감소하였다. 기판온도를 100∼400℃ 범위에서 변화시켜 박막의 물성을 살펴 본 결과 결정화분율은 250℃에서 최대를 나타내었고, 박막내 수소량과 광학적 에너지갭은 기판온도가 증가함에 따라 감소하였다.B-doped hydrogenated amorphous silicon(a-Si:H) films were deposited on glass substrates using plasma-enhanced chemical-vapor deposition(PECVD). The films were characterized with X-ray diffraction, Raman scattering spectroscopy, infrared spectroscopy, and UV transmission analyses. With an increase in gaseous doping level, [B₂H6]/[SiH₄], in the range of 3×10-³to 5×10², the volume fraction of microcrystalline phase in the film was increased while the optical energy bandgap(Eg.opt) and the electrical resistivity were decreased. With increasing substrate temperature from 100 to 400℃, however, the hydrogen content and the Eg.opt decreased. But the volume fraction of microcrystalline phase showed a maximun at 250℃.B-doped hydrogenated amorphous silicon(a-Si:H) films were deposited on glass substrates using plasma-enhanced chemical-vapor deposition(PECVD). The films were characterized with X-ray diffraction, Raman scattering spectroscopy, infrared spectroscopy, and UV transmission analyses. With an increase in gaseous doping level, [B₂H6]/[SiH₄], in the range of 3×10-³to 5×10², the volume fraction of microcrystalline phase in the film was increased while the optical energy bandgap(Eg.opt) and the electrical resistivity were decreased. With increasing substrate temperature from 100 to 400℃, however, the hydrogen content and the Eg.opt decreased. But the volume fraction of microcrystalline phase showed a maximun at 250℃

Electrical Properties of (Ba,Sr)TiO₃Thin Films Deposited at Low Temperatures by Reactive RF Magnetron Sputtering

세라믹 (????)TiO₃타겟을 이용하여 RF magnetron sputtering 법으로 Pt/Ti/SiO₂/Si기 위에 300℃이하의 저온에서 BST 박막을 증착하였다. 본 연구에서는 증착변수인 기판온도와 양의 기판 DC bias 가 박막의 물성 및 전기적 특성에 미치는 영향을 주로 살펴보았다. 기판의 온도와 인가된 양의 기판 DC bias가 증가할수록 증착된 BST 박막의 결정성이 증가하였다. 증착된 박막은 타겟 조성보다 Ba Sr의 양이 결핍되었지만 다결정상의 BST가 형성되었으며 증착 중에 양의 기판 DC bias를 인가하면 박막의 방향성 성장을 촉진시켜 박막의 성장속도와 결정성이 향상되었다. 100kHz에서의 유전울 및 유전손실은 기판온도가 증가함에 따라 20∼82와 2.6∼6.5%로 증가하였고 양의 기판 DC bias를 인가하면 유전율과 유전선실이 약간 감소하였다. 그러나 기판온도와 양의 기판 DC bias가 증가할수록 박막의 누설전류를 감소하였다.(Ba,Sr)TiO₃(BST) thin films were deposited on Pt/Ti/SiO₂/Si substrates at low temperatures below 300℃ by reactive RF magnetron sputtering methods. The electrical properties of the deposited films were investigated by controlling deposition parameters such as substrate temperature and positive substrate DC bias. The crystallinity of the BST film increased with increasing substrate temperature and positive substrate DC bias. The amounts of Ba and "Sr in the film, however, were less than those of a target. With increasing substrate temperature and positive substrate DC bias, the deficiency of Ba and Sr in the film was decreased. Dielectric constant and dielectric loss measured at 100kHz were increased from 20to 82and from 2.6 to 6.5%, respectively, with increasing substrate temperature in the range of 80~300℃, but were decreased a little with the positive substrate DC bias. The leakage current density of BST thin film capacitors was reduced with increasing substrate temperature and positive substrate DC bias.(Ba,Sr)TiO₃(BST) thin films were deposited on Pt/Ti/SiO₂/Si substrates at low temperatures below 300℃ by reactive RF magnetron sputtering methods. The electrical properties of the deposited films were investigated by controlling deposition parameters such as substrate temperature and positive substrate DC bias. The crystallinity of the BST film increased with increasing substrate temperature and positive substrate DC bias. The amounts of Ba and "Sr in the film, however, were less than those of a target. With increasing substrate temperature and positive substrate DC bias, the deficiency of Ba and Sr in the film was decreased. Dielectric constant and dielectric loss measured at 100kHz were increased from 20to 82and from 2.6 to 6.5%, respectively, with increasing substrate temperature in the range of 80~300℃, but were decreased a little with the positive substrate DC bias. The leakage current density of BST thin film capacitors was reduced with increasing substrate temperature and positive substrate DC bias

Thermal modeling of a lithium-ion battery for electric vehicle applications

학위논문(박사)--아주대학교 일반대학원 :에너지시스템학과,2016. 2Chapter 1. Introduction 1 1.1. Lithium-ion battery 1 1.2. Thermal issues of LIB 5 1.2.1. Safety issues related with thermal effect of LIB 5 1.2.2. Ageing issues related with thermal effect of LIB 6 1.2.3. Thermal modeling of LIB 7 1.3. Objectives 10 Chapter 2. Modeling the temperature dependence of the discharge behavior of a lithium-ion battery in low environmental temperature 12 2.1. Introduction 12 2.2. Mathematical model 15 2.3. Results and discussion 29 Chapter 3. Modeling of the transient behaviors of a lithium-ion battery during dynamic cycling 43 3.1. Introduction 43 3.2. Mathematical model 44 3.3. Results and discussion 56 Chapter 4. Three-dimensional thermal modeling of a lithium-ion battery considering the combined effects of the electrical and thermal contact resistances between current collecting tab and lead wire 74 4.1. Introduction 74 4.2. Mathematical model 76 4.3. Results and discussion 82 Chapter 5. Summary and Conclusions 103 Chapter 6. Recommendations for Further Research 106 Bibliography 110 국 문 초 록 119 List of publications 121 Appendix A. Nomenclature 127 Appendix B. Experimental measurements 130 Appendix C. Battery glossary 133DoctoralThe lithium-ion battery (LIB) is a preferred power source for electrically propelled vehicles because of its high energy density, high power, and low self-discharge rate. Because battery performance and battery life are strongly dependent on battery temperature, thermal control of the LIB is particularly important. To control the temperature of an LIB cell within a suitable range for the various electrically propelled vehicles operating conditions, it is essential to calculate the uneven temperature distribution of an LIB cell accurately based on thermal modeling and to validate the model by comparing the modeling results with the experimental measurements. Modeling can play an important role for exploring various battery pack cooling strategies in electrically propelled vehicle applications. This thesis reports a modeling methodology of an LIB considering the effects of the various conditions for electrically propelled vehicle applications. These include modeling of the temperature dependence of the discharge behavior of an LIB in low environmental temperature, modeling of the transient behaviors of an LIB battery during dynamic cycling, and Three-dimensional thermal modeling of an LIB considering the combined effects of the electrical and thermal contact resistances between current collecting tab and lead wire. The first part of this thesis is a modeling methodology on the temperature dependence of the discharge behavior of an LIB in low environmental temperature. The discharge curves from the modeling for the discharge rates ranging from 0.5 C i to 5 C under the low environmental temperatures of -20, -10 and 0 oC are compared with the experimental data in order to validate the two-dimensional modeling of the potential and current density distributions on the electrodes of an LIB cell as a function of the discharge time during constant-current discharge. The heat generation rates as a result of electrochemical reactions and ohmic heating are calculated to predict the temperature variations of the LIB as a function of the discharge time. The temperature variations obtained from the modeling agree well with the experimental measurements. The second part of this thesis is a modeling methodology on the transient behaviors of an LIB during dynamic cycling. To account for the short time effects of current pulses and rest periods, the nonfaradaic component of the current density transferred through the separator between the positive and negative electrodes is included based on the lumped double-layer capacitance. Two-dimensional modeling is performed to predict the transient behaviors of an LIB cell during dynamic cycling. To validate the modeling approach presented in this part, modeling results for the variations in cell voltage and two-dimensional temperature distribution of the LIB cell as a function of time are compared with the experimental data for constant-current discharge and charge cycles and the Heavy Duty Urban Dynamometer Driving Schedule cycles. The transient behaviors obtained from the modeling agree well with the experimental measurements. The last part of this thesis is Three-dimensional thermal modeling of an LIB considering the combined effects of the electrical and thermal contact resistances ii between current collecting tab and lead wire. The combined effects of the thermal and electrical contact resistances between the current collecting tab of an LIB cell and the lead wire connecting the cell to an external cycler are considered explicitly in addition to the heat generated as a result of electrochemical reactions and ohmic heating in the electrode region of the battery cell. The effect of electrical contact resistance is taken into account when calculating current collecting tab heating, and the effect of thermal contact resistance is included in the heat flux boundary condition at the contact area between the current collecting tab and the lead wire. The three-dimensional thermal modeling is validated by comparing the modeling results with experimental temperature distributions from IR images during discharge in an LIB cell

Jae shin Lee

학위논문(석사)--아주대학교 일반대학원 :경영학과,2009. 2Bharath와 Shumway는 “Forecasting Default with the Merton Distance to Default Model", RFS,2008에서 미국 기업 데이터를 바탕으로 Merton모형의 유의성을 테스트 하였다. 본 논문은 Merton의 채권 가격 결정 모델 (1974)에 근거하여 부도 확률을 추정하는 Merton distance to default (DD) 모형의 유의성을 Bharath와 Shumway가 이용한 방법론을 적용하여 KOSPI 상장 기업들을 대상으로 테스트 해 보고, 그들의 주장이 미국과 다소 시장 여건이 다른 국내 시장에서도 성립하는 지 여부를 검토하였다. 본 논문에서는 이러한 Merton 모형을 이용하여 부도 확률을 계산한 결과와, 이를 대체하기 위해 Bharath와 Shumway가 제안한“naive"한 모델을 통해 계산된 부도 확률을 비교해 보았다. “naive”한 모델은 Merton 모형에서 쓰이는 부도거리(distance to default)의 구조적인 형태를 동일하게 사용하지만, 실질적으로 iterative한 방법을 통해 내재부도확률(implied probability of default)을 계산해 낼 필요가 없는 단순성을 지닌다. 본 연구에서는 국내 시장에 있어서도 이러한 “naive"한 예측치가 Merton DD 모형 의 예측치 보다 hazard models내의 유의성과 out-of-sample 테스트의 예측력에 있어 좀 더 우월하다는 결론을 도출하였다. 결론적으로, Merton DD 모형은 부도에 대한 충분한 확률 예측치를 도출한다고 볼 수는 없으나, Merton DD 모형의 함수적 형태 는 부도 위험을 예측하는데 유용하다는 Bharath와 Shumway의 주장은 KOSPI 기업을 대상으로 검증하였을 때에도 설득력을 갖는다.제1장 서 론 5 제1절 연구의 목적 5 제2절 논문의 구성 7 제2장 부도 예측 모델들 8 제1절 The Merton Distance to Default (DD) 모형 8 제2절 Moody's KMV 모형 10 제3절 A naive alternative 11 제4절 Hazard models 13 제3장 데이터 17 제4장 결 과 21 제1절 Hazard model의 결과 21 제2절 Out-of-sample Test결과 24 제3절 Mu에 따른 비교 분석 29 제5장 결 론 33Maste

Fabrication of MHz-Band Piezoelectric Resonators Using Nd-Modified PbTiO₃ Ceramics

Nd의 치환량을 0∼20 at.%범위로 변화시켜 제조한 (Pb₁-₃/₂xNdx)(Ti0.98Mn0.02)O₃세라믹의 재료적 성질과 ?隙幌?성을 살펴보았다. Nd이 첨가되지 않은 Pb(Ti0.98Mn0.02)O₃는 소결성이 불량하고 냉각중에 파괴되는 문제가 발생하였으나 Nd³+ 이 Pb²+를 치환함에 따라 격자이방성이 감소하였고, 소결성도 향상되어 치밀한 미세구조를 얻을 수 있었다. (Pb₁-₃/₂xNdx)(Ti0.98Mn0.02)O₃ 세라믹의 전기기계적 이방성(kt/kp)은 x=0.1일 때 최대를 보였으며, 이는 2가인 Pb 격자점을 3가인 Nd이 치환함에 따라 결정이방성이 감소하지만, Pb-vacancy가 생성되어 분극을 용이하게 되는 두가지 상반된 효과의 결과로 생각된다. (Pb0.85Nd0.1)(Ti0.98Mn0.02)O₃세라믹을 이용하여 두께전단모드 공진자를 제작하였다. 공진자의 두께를 0.3, 0.5mm일 때 기본공진주파수가 각각 2.7, 4.5MHz였으며, 소재의 k15는 0.33이었다. 공진자의 불요파는 전극의 중첩도에 민감한 의존성을 나타내었으며, 전극의 중첩도를 적정화함으로써 실용성이 높은 공진자를 얻을 수 있었다.Microstructures and piezoelectric properties of (Pb₁-₃/₂xNdx)(Ti0.98Mn0.02)O₃(x=0∼0.2) ceramics have been investigated. Pb(Ti0.98Mn0.02)O₃ showed poor sinterability and cracking on cooling, but the substitution of Nd³+ into Pb²+ sites resulted in dense microstructures with reduced crystallographic anisotropy. Electromechanical anisotropy(kt/kp) showed a maximum value of 10 when x=0.1. This result might be attributed to the counteracting effects that with increasing x, the lattice anisotropy decreases, but the poling process becomes easier due to the increase in Pb-vacancy concentration. Thickness-shear mode resonators were fabricated by using (Pb0.85Nd0.1)(Ti0.98Mn0.02)O₃ ceramics. Fundamental resonant frequencies were 4.5 and 2.7MHz for the resonators with thicknesses of 0.3 and 0.5mm, respectively. By optimizing electrode configuration, we obtained good resonant characteristics enough for practical application.Microstructures and piezoelectric properties of (Pb₁-₃/₂xNdx)(Ti0.98Mn0.02)O₃(x=0∼0.2) ceramics have been investigated. Pb(Ti0.98Mn0.02)O₃ showed poor sinterability and cracking on cooling, but the substitution of Nd³+ into Pb²+ sites resulted in dense microstructures with reduced crystallographic anisotropy. Electromechanical anisotropy(kt/kp) showed a maximum value of 10 when x=0.1. This result might be attributed to the counteracting effects that with increasing x, the lattice anisotropy decreases, but the poling process becomes easier due to the increase in Pb-vacancy concentration. Thickness-shear mode resonators were fabricated by using (Pb0.85Nd0.1)(Ti0.98Mn0.02)O₃ ceramics. Fundamental resonant frequencies were 4.5 and 2.7MHz for the resonators with thicknesses of 0.3 and 0.5mm, respectively. By optimizing electrode configuration, we obtained good resonant characteristics enough for practical application