원칩마이크로컨트롤러를 이용한 단상유도전동기의 기동시스템 구현

백형래,박수강,최낙일 조선대학교 에너지.자원신기술연구소 1998 에너지·자원신기술연구소 논문지 Vol.20 No.2

A single phase induction motor(SPIM) with two windings, main and auxiliary is probably the most widely used motor in the world due to their ruggedness, low maintenance and simplicity of construction. There are several ways of starting single phase motors. The most popular arrangements is centrifugal switch. An auxiliary winding connected in series with a capacitor, is brought into the circuit during starting. The closing and opening of the switch must be speed dependant. The switch meets the speed requirements, but it also has many drawback: random switching, arcing, many models necessary for different speeds and shaft diameters, space required inside the motors and limited lifetime to name some of them. In this paper, authors present the experimental results of the SPIM under controlling of currents of main and auxiliary windings by using a one-chip micro starter. This new starting method is developed to replace the conventional starting device consisted with a mechanical switch and a capacitor. In mentioned method the soft-starting of SPIM is simply implemented and higher efficiency is obtained in comparison with conventional condenser type SPIM.

치과용 금합금과 상변태

김형일,백창준,이경희,이희경 大韓齒科器材學會 2000 대한치과재료학회지 Vol.27 No.3

스트론튬이 도프된 페로브스카이트 La_1-x Sr_xCoO_3의 환원 반응

박일현,이형표,백성현 성균관대학교 기초과학연구소 1988 論文集 Vol.39 No.2

Sr-doped lanthanum cobalt oxides having perovskite structure, La_1-xSr_xCoO_3 (x=0, 0.2, 0.4, 0.6), were prepared in air at 1000℃ by ordinary solid state reactions and their physicochemical properties including particle morphology, non-stoichiometry, stability and reducibility were characterized by the use of TPR, XRD and SEM techniques. Particle size is not considerably affected by impurity dopant (Sr^2+ ion) but reduction behaviors and thermal stability were markedly varied according to the amounts of Sr (various x values). All these perovskites have oxygen deficient structure as follows. LaCoO_2.94, La_0.8Sr_0.2CoO_2.94, La_0.6Sr_0.4CoO_2.88, La_0.4Sr_0.6CoO_2.83. Finally, kinetics of reduction on each stage was discussed using well-established reduction models and kinetic parameters, activation energy and preexponential term, were evaluated from the optimum reaction model.

연속공정시스템의 고속 고정도 장력제어시스템

이진섭,백형래,이상일 조선대학교 에너지.자원신기술연구소 2001 에너지·자원신기술연구소 논문지 Vol.23 No.1

This paper deals with the tension control of state feedback control for continuous processing line. At the starting point of entry section, for example, a unwinder named pay off reel unwinds the material maintaining constant tension and line speed. Speed and torque characteristics state is variance during acceleration and deceleration period. In simulation roll diameter variation and inertia variation are considered. It becomes clear that the proposed tension control system has high accuracy performance.

반측안면소체증의 측두골 전산화 단층촬영소견

한종규,한경렬,백병준,김형환,배원경,김일영 순천향의학연구소 2005 Journal of Soonchunhyang Medical Science Vol.11 No.1

Hemifacial microsomia(HFM) is a craniofacial disorder and complex malformation syndrome with a variable and asymmetric malformation involving first and second pharyngeal arch derivatives. Multiple etiological mechanisms for HFM have been considered. Mechanisms proposed include genetic factors, early embryogenesis insults involving abnormal neural crest development and migration, and stapedial artery hematoma. HFM is the second most common craniofacial malformation but has been rarely reported in korea, and we report five cases of HFM in temporal bone CT findings. The temporal bone CT findings of five patients aged 6 days and 19 years(mean, 9 years) with hemifacial microsomia were reviewed and evaluated. Particular attention was focused on auricular malformation, external auditory canal, volume of middle ear cavity, ossicular anomaly, facial nerve anomaly and inner ear anomaly. In all patients, temporal bone CT scans revealed the stenosis or atresia of external auditory canals, decreased middle ear cavities, matoid underdevelopment and ossicular anomalies including ossicular ankylosis, but only one patient showed facial nerve or inner ear anomaly. In conclusion, temporal bone CT scan is a useful diagnosis modality of hemifacial microsomia, which is especially more useful in preoperative evaulation and estimation of postoperative prognosis that demonstate middle and inner ear anomalies.

전류제어에 의한 단상유도전동기의 기동특성 개선

박수강,최낙일,백형래,임양수,이기용,신사현 조선대학교 에너지.자원신기술연구소 1998 에너지·자원신기술연구소 논문지 Vol.20 No.1

A single phase induction motor(SPIM) with two windings, main and auxiliary, is probably the most widely used motor in the world due to their ruggedness, low maintenance and simplicity of construction There are several ways of starting single phase motors The most popular arrangements is centrifugal switch An auxiliary winding connected in series with a capacitor, is brought into the circuit during starting The closing and opening of the switch must be speed dependant The switch meets the speed requirements, but it also has many drawback random switching, arcing, many models necessary for different speeds and shaft diameters, space required inside the motors and limited lifetime to name some of them. In this paper, the starting current of single phase induction motor was detected by a small detector and determined TRIAC gate signal. The strategy of current control is based on limited main and auxiliary current angle during starting period in the closed-loop control. The experimental result show the motor's starting characteristics of the proposal starting system and are compared with centrifugal switch starting motor.

연장 가골에 골 이식 대체물 투여가 골 경화에 미치는 영향 : 가토 경골에서의 방사선 및 골 밀도의 변화 Changes of Radiography & Bone Mineral Density in the Tibia of Rabbits

오창욱,김풍택,박병철,송해룡,박일형,백준호,박형진 경북대학교 병원 2003 경북대학교병원의학연구소논문집 Vol.7 No.1

목적 : 골 연장술 후 생기는 연장 가골에 황화 칼슘과 이종 이식골을 투여하여 골 경화 속도에 대한 영향을 알아보기 위한 실험이었다. 연구대상 및 방법 : 성장중인 뉴질랜드 화이트 토끼(2.0-2.5㎏)의 경골 간부에 골막을 보호하고, 절골술을 시행하고, 5일간의 휴지기후 외고정 장치를 이용하여 1주일 동안 7㎜가 연장될 때까지 하루 1㎜씩 2회의 리듬을 가지고 골 연장을 실시하였다. 제1 실험 군 7마리에는 연장이 끝난 직후 황화 칼슘(Osteoset^(ⓡ), Wright medical USA) 1정, 제 2 실험 군 7마리에는 이종 이식골의 일종인 Lubboc 5㎟을 각각 연장된 가골 부에 주입하고, 단순 연장한 대조군 7마리와 함께, 방사선 및 골 밀도비를 측정하고 추시하여, 골 경화의 진행속도를 비교하였다. 방사선 촬영은 전후면 및 측면사진을 1주 간격으로 촬영하였고, 골밀도 측정은 DEXA(dual energy X-ray absorptionmetry, Lunar^(ⓡ)) 장치를 2주일 간격으로 시행하였다. 결과 : 방사선 소견상, 제 1실험군의 연장가골의 완전 경화시간은 평균 14주, 제 2실험군은 154 주로 각각 대조군의 16.9주보다 단축되었으며, 골 밀도 비에서도, 두 실험군에서 최고치가 대조군의 값보다 높고, 최고치까지의 경과기간도 빨랐다. 결론 : 본 연구에서 연장 가골에 황화칼슘 및 이종 이식골의 투여가 골 경화의 기간을 단축시킬 수 있고, 외고정 장치의 빠른 제거에 도움이 될 수 있음을 알았다. Purpose : This study was designed to know the effect of calcium-sulfate and xenograft on the distracted callus after lengthening. Materials & Methods : We had operation of subperiosteal osteotomy and external fixation on the tibial diaphysis of young New Zealand White rabbits(2.0-2.5㎏); after 5 days of latency period, 7㎜(1㎜/day, 2times/day) of tibial lengthening was reached in a week. At 1 week after lengthening, the 1st experimental group of 7 rabbits received a pellet of calcium sulfate(Osteoset, Wright medical, USA) in the distraction gap, and the 2nd experimental group of 7 rabbits received 5㎜ 2 of xenogrfat(Lubboc) in the distraction gap. But, the control group of 7 rabbits did not receive any of above materials. We compared three groups with the changes of radiographic findings at every week and bone mineral ratio(DEXA) at every two weeks. Results : The time to complete consolidation of distraction callus of both experimental group(calcium sulfate;14 weeks, xenograft; 15.4 weeks) was shorter than that of control group(16.9 weeks) in radiographic findings. Maximum value of bone mineral ratio of distraction callus was higher and the time to reach the highest value was also shortened in the both experimental group compared to control group. Conclusion : By use of bone substitutes as like calcium sulfate or xenograft in the distraction callus with external fixator, it may be possible to shorten the consolidation period and the fixator-wearing period.

노인 인구에서 신경인지기능저하와 혈청 지질농도와의 상관성

유영선,최석주,정성수,김지은,윤성욱,전동욱,백준형,박성우,이정구,추일한,김영훈 大韓神經精神醫學會 2008 신경정신의학 Vol.47 No.6

Objectives : In this study, the authors evaluated the correlation between eurocognitive impairments and serum lipids levels among Korean elderly over the age of 65. Methods : A total of 609 elderly individuals participated in this study. Screening for cognitive impairments were carried out using the Mini-Mental Status Examination-Korean version (MMSE-KC). There were 197 subjects above 1.5SD Of MMSE- KC and they were evaluated using the Korean versions of the Consortium to Establish a Registry for Alzheimer's Disease (AD) (CERAD-KC) and Geriatric Depression Scale (GDS-K). Results : There was a correlation between old age/low levels of education and AD (p<0.05, P<0.01). There was an inverse correlation between the serum level of total cholesterol and the word list recognition test scores. The serum levels of LDL cholesterol were inversely correlated with the scores on the constructional praxis test, word list recall test and word list recognition test. Inverse correlations between the serum level of triglyceride and scores on the word list recall test and word list recognition test were also observed. Conclusion : There were inverse correlations between the serum levels of lipids and language/memory function in subjects with AD.

Design of a Reconfigurable Active Bandpass Filter Based on a Controllable Slope Parameter

Hyung-Il Baek,Young-Ho Cho,Xu-Guang Wang,Hye-Min Lee,Sang-Won Yun IEEE 2011 IEEE microwave and wireless components letters Vol.21 No.12

<P>This letter presents a reconfigurable active bandpass filter based on a controllable slope parameter. The proposed filter has reconfigurable bandwidths and center frequencies, and both can be continuously changed using varactor diodes as the tuning elements. The wide tuning range of the bandwidth is achieved by adjusting the slope parameter of the resonators. This letter describes the design and testing of a two-pole reconfigurable filter with tuning ranges in the center frequency of 2.0-2.6 GHz and 3 dB bandwidth of 127-598 MHz at the center frequency of 2.15 GHz.</P>

Characterization of phenotypes and predominant skeletodental patterns in pre-adolescent patients with Pierre–Robin sequence

Il-Hyung Yang,Jee Hyeok Chung,Hyeok Joon Lee,Il-Sik Cho,Jin-Young Choi,Jong-Ho Lee,Sukwha Kim,Seung-Hak Baek 대한치과교정학회 2021 대한치과교정학회지 Vol.51 No.5

Objective: To investigate the phenotypes and predominant skeletodental pattern in pre-adolescent patients with Pierre–Robin sequence (PRS). Methods: The samples consisted of 26 Korean pre-adolescent PRS patients (11 boys and 15 girls; mean age at the investigation, 9.20 years) treated at the Department of Orthodontics, Seoul National University Dental Hospital between 1998 and 2019. Dental phenotypes, oral manifestation, cephalometric variables, and associated anomalies were investigated and statistically analyzed. Results: Congenitally missing teeth (CMT) were found in 34.6% of the patients (n = 9/26, 20 teeth, 2.22 teeth per patient) with 55.5% (n = 5/9) exhibiting bilaterally symmetric missing pattern. The mandibular incisors were the most common CMT (n = 11/20). Predominant skeletodental patterns included Class II relationship (57.7%), posteriorly positioned maxilla (76.9%) and mandible (92.3%), hyper-divergent pattern (92.3%), high gonial angle (65.4%), small mandibular body length to anterior cranial base ratio (65.4%), linguoversion of the maxillary incisors (76.9%), and linguoversion of the mandibular incisors (80.8%). Incomplete cleft palate (CP) of hard palate with complete CP of soft palate (61.5%) was the most frequently observed, followed by complete CP of hard and soft palate (19.2%) and CP of soft palate (19.2%) (p < 0.05). However, CP severity did not show a significant correlation with any cephalometric variables except incisor mandibular plane angle (p < 0.05). Five craniofacial and 15 extra-craniofacial anomalies were observed (53.8% patients); this implicated the need of routine screening. Conclusions: The results might provide primary data for individualized diagnosis and treatment planning for pre-adolescent PRS patients despite a single institution-based data.