• 제목/요약/키워드: Initial center

검색결과 3,428건 처리시간 0.034초

평판형 전자기 엑츄에이터의 초기응답속도 향상을 위한 쇼티트 턴에 관한 연구 (Single-axis Flat Electro-Magnetic Actuator using Shorted Turn for Fast Initial Response)

  • 황기일;김진호
    • 한국자기학회지
    • /
    • 제19권6호
    • /
    • pp.222-226
    • /
    • 2009
  • 기존의 평판형 전자기 엑츄에이터에 쇼티드 턴을 적용한 새로운 형태의 평판형 전자기 엑츄에이터를 제안하였다. 기존의 평판형 전자기 엑츄에이터에서 발생하는 인덕턴스에 의한 초기응답 지연현상을 줄이기 위해 본 논문에서는 기존의 엑츄에이터의 요크와 요크 사이에 중간요크(center yoke)를 추가하고, 쇼티드 턴을 적용한 새로운 형태의 평판형 전자기 엑츄에이터를 제안 하고, 상용 자기장 해석 프로그램인 MAXWELL을 이용한 시뮬레이션을 통해 동적 성능 향상을 검증 하였다.

접촉 유한요소모델을 이용한 미니 임플란트의 초기 응력분포 연구 (Contact non-linear finite element model analysis of initial stability of mini implant)

  • 윤현주;정의원;이종석;김창성;김정문;조규성;김종관;최성호
    • Journal of Periodontal and Implant Science
    • /
    • 제37권4호
    • /
    • pp.681-690
    • /
    • 2007
  • Mini implants had been used provisionally for the healing period of implants in the beginning. But it becomes used for the on-going purpose, because it is simple to use, economic and especially suitable for the overdenture. But there is few studies about the stability of mini implants, that is most important factor for the on-going purpose, and particularly the implant parameters affecting the initial stability. The purpose of this study was to evaluate the stress and the strain distribution pattern of immediate-loaded screw type orthodontic mini-implant and the parameters affecting the initial stability of immediate-loaded mini-implant. Two dimensional finite element models were made and contact non-linear finite element analysis was performed. The magnitude and distribution of Von Mises stresses were evaluated. The obtained results were as follows: 1. The stress was concentrated on the thread tip of an implant in the cortical bone. 2. The direction of load is the most important factor for the stress distribution in cortical bone. 3. The diameter of an implant is the most important factor for the stress distribution in the trabecular bone. In conclusion, if the horizontal load vector is successfully controlled, mini-implants, which diameter is under 3mm, can be used for the on-going purpose.

멀티콥터 초기 사이징을 위한 기체 구조 중량 예측 기법 (Airframe Weight Estimation Method for Initial Sizing of Multicopter)

  • 장병욱;황인성;김민우;이보성;정용운;강왕구
    • 한국항공우주학회지
    • /
    • 제46권9호
    • /
    • pp.723-734
    • /
    • 2018
  • 20kg 미만의 중소형 멀티콥터의 초기 사이징 과정에서 적용 가능한 기체 구조 중량 예측에 관한 연구를 소개한다. 임무장비를 제외하고 멀티콥터는 기체 구조, 모터, 프로펠러, 배터리 등으로 구성되는데, 모터, 프로펠러, 배터리 등의 중량은 설계변수에 따른 추세선을 통해 추정이 가능하다. 하지만 기체 구조 중량은 멀티콥터의 형상과 설계 개념이 다양하고, 대부분의 상용 제품들이 기체 구조 중량 데이터를 제공하지 않기 때문에 추세선을 통해 예측할 수 없다. 본 논문에서는 기본적인 멀티콥터 형상을 정의하고 멀티콥터 사이징 초기 단계에서 결정되는 프로펠러 개수와 직경을 통해 멀티콥터 기체 구조 중량을 추정하는 방법을 제안하였다. 제안한 방법은 구조 중량이 제시된 멀티콥터 제품들을 통해 검증하여 그 유용성을 확인하였다.

Characterization of Grape Seed Oil

  • Kang, Han-Chul;Park, Won-Jong;Kim, Si-Dong;Park, Jong-Cheon
    • Applied Biological Chemistry
    • /
    • 제41권8호
    • /
    • pp.578-582
    • /
    • 1998
  • Grape seed oil was characterized to assess the usefulness in the food industry. Among the various oils, the initial antioxidant activity was the highest for grape seed oil. Heating the oil at $180^{\sim}C$ for 20 min retained 86% of the initial activity. Grape seed and sesame oils showed a low peroxide value, about 2, implying a less oxidative reaction. The oxidation of grape seed oil was increased to a less extent by heat-treatment than other oils. Light exposure for 1 month resulted in a slight decrease in the antioxidant activity of grape seed oil, maintaining 96% of the initial activity. Other oils were all light-susceptible and the activities decreased significantly. The peroxide values of all the oils increased by light exposure, but the extent of oxidation was still the least for grape seed oil. The addition of grape seed oil to perilla oil was very effective, in that the peroxide value was 5-times decreased by 1 : 5 composition of grape seed oil versus perilla oil. These results indicate that grape seed oil can be used as a good cooking oil or an additive for other oils.

  • PDF

폐결핵(肺結核) 환자(患者)에서 수소(愁訴)가 치료과정(治療過程)에 미치는 영향(影響) (The Influence of Subjective Complaints to the Course of Treatment in Pulmonary Tuberculosis Patients)

  • 김상수
    • Journal of Preventive Medicine and Public Health
    • /
    • 제15권1호
    • /
    • pp.125-130
    • /
    • 1982
  • In order to investigate the relation of subjective complaints to objective course of treatment in pulmonary tuberculosis, one hundred and seventy four cases registered at the University Health Center in Chonnam University were divided into two groups, complaint group and non-complaint group. By analysing the record at the University Health Center during these seven years from 1973 to 1979, following results were obtained: 1. In complaint group who had subjective symtoms, thirty eight cases(77.6%) among forty nine cases were detected. at clinic visit. In non-complaint group who had not any symtoms, one hundred and twenty one cases (96.8%) among one hundred and twenty five cases were detected at compulsive physical examination. 2. Comparisons of complaint group with non-complaint group were not statistically significant in many aspects, but significantly higher cases were discharged at the University Health Center to receive other medical service in complaint group than in non-complaint group. (6.1% vs 0.8%, respectively) On the contrary, non-complaint group refused medication more than two times compared with complaint group in the course of treatment (29.9% vs 12.2%, respectively). 3. In the average time lag from initial diagnosis to initial treatment, comparisons between complaint vs non-complaint group were significant (7.8 vs 28.3 days, respectively). 4. Subjective symptoms were thought to create motivation to receive therapy, and influence of motivation to therapy was strong at initial stage but it become weaker as time passed.

  • PDF

한국형 재해평가모형(RAM)의 초기입력자료 적합성 평가 (Compatibility for the Typhoon Damages Predicted by Korea Risk Assessment Model Input Data)

  • 박종길;이보람;정우식
    • 한국환경과학회지
    • /
    • 제24권7호
    • /
    • pp.865-874
    • /
    • 2015
  • This study was conducted to investigate the correlation between the distribution chart and input data of the predicted 3-second gust and damage cost, by using the forecast field and analysis field of Regional Data Assimilation Prediction System (RDAPS) as initial input data of Korea risk assessment model (RAM) developed in the preceding study. In this study the cases of typhoon Rusa which caused occurred great damage to the Korean peninsula was analyzed to assess the suitability of initial input data. As a result, this study has found out that the distribution chart from the forecast field and analysis field predicted from the point where the effect due to the typhoon began had similarity in both 3-second gust and damage cost with the course of time. As a result of examining the correlation, the 3-second gust had over 0.8, and it means that the forecast field and analysis field show similar results. This study has shown that utilizing the forecast field as initial input data of Korea RAM could suit the purpose of pre-disaster prevention.

THE COMPARISON OF INITIAL RETENTIVE FORCE IN DIFFERENT DOUBLE CROWN SYSTEMS

  • Kwon, Ho-Beom;Roh, Yoon-Ho;Lee, Seok-Hyung
    • 대한치과보철학회지
    • /
    • 제44권6호
    • /
    • pp.677-682
    • /
    • 2006
  • Statement of problem. Various double crown systems have been used with removable partial dentures in the clinical field. Although retentive force between inner and outer crown are affected by several factors, differences between the retentive forces of different double crown system types are expected. Purpose. The purpose of this study was to evaluate the initial retentive force of outer crowns fabricated by the conventional casting technique in conus and hybrid double crowns. Material and methods. Ten double crowns were fabricated. The groups were as follows. Group 1, double crowns of hybrid inner and outer crowns using the conventional casting method; Group 2, double crowns of conus inner and outer crowns using the conventional casting method. Tensile strengths of double crowns when the inner and outer crowns were separated on a universal testing machine were measured. These values of retentive force were then statistically analyzed using the Kruskal-Wallis test. Results. Retentive force in group 2 was significantly higher than that in group 1(p<.05). Conclusion. The initial retentive forces of double crowns were affected by the types of the double crown system.

Removal of Methylene blue from saline solutions by adsorption and electrodialysis

  • Lafi, Ridha;Mabrouk, Walid;Hafiane, Amor
    • Membrane and Water Treatment
    • /
    • 제10권2호
    • /
    • pp.139-148
    • /
    • 2019
  • In this study, the removal of MB from saline solutions was evaluated by two methods by adsorption and electrodialysis; the adsorption of the mixture dye/salt on dried orange peel waste (OPW) was studied in batch method. In this study the biosorption of cationic dye by OPW was investigated as a function of initial solution pH, and initial salt (sodium chloride) concentration. The maximal dye uptake at $pH{\geq}3.6$ in the absence and in the presence of salt and the dye uptake diminished considerably in the presence of increasing concentrations of salt up to 8 g/L. The Redlich Peterson and Langmuir were the most suitable adsorption models for describing the biosorption equilibrium data of the dye both individually and in salt containing medium. As well, this work deals with the electrodialysis application to remove the dye. Synthetic solutions were used for the investigation of the main operational factors affecting the treatment performance; such as applied voltage, pH, initial dye concentration and ionic strength. The experimental results for adsorption and electrodialysis confirmed the importance of electrostatic interactions on the dye. The electrodialysis process with standard ion exchange membranes enabled efficient desalination of cationic dye solutions; there are two main factors in fouling: electrostatic interaction between cations of dyes and the fixed charged groups of the CEM, and affinity interactions.