• 해양환경안전학회지
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• 제23권1호
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• pp.40-46
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• 2017

본 연구는 LS-DYNA 971 을 이용하여 내빙 구조 선박과 빙산 모형 간의 충돌 시험을 수행 후 북극해 운항 선박의 내빙 능력을 분석하였다. 국제선급연합회(IACS)의 Unified Requirements for Polar ship(URI) 규정을 바탕으로 FEM 선박 모형에 내빙 구조를 적용하였으며, 빙산 모형에는 Elastic-perfect plastic 물성과 Tsai-Wu 항복 곡면을 적용하였다. 또한 실험 결과 비교를 위하여 내빙 구조를 갖추지 않은 일반선박 모형과의 충돌 시험도 수행하였다. 실험 결과 일반 구조 선박의 구형 선수에 빙산 모형에 의해 움푹 들어간 약 1.8 미터 깊이의 선체 손상이 발생하였으나, 내빙 구조 선박의 충돌에서는 약 1.0 미터 깊이의 선체 손상만이 발생하였다. 또한 일반 구조 선박과 충돌한 빙산모형은 원형의 상태를 거의 유지한 반면, 내빙 구조 선박과 충돌한 빙산 모형은 내빙 구조의 구형 선수에 의해 빙산이 일부 파괴되는 현상이 발견되었다.

• 한국과학교육학회지
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• 제26권5호
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• pp.660-673
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• 2006

There have been many attempts to determine the value and the role of school laboratory experiment, but it seems hard to find consensus among these attempts from the perspective of education. This difficulty seems mainly due to disagreement on the concept of education, which has caused an instrumental attitude considering the school laboratory only as a means of developing science or pursuing various functions of school. However, the Endogenous Theory of Education (ETE), which claims education as 'a form of life', has recently paved the way for laboratory experiment to be justified as an opportunity of 'educooperation' allowing students to experience the intrinsic values of education in the medium of science. According to this theory, it is not the detailed practicals but the whole context where the laboratory activity is situated that matters in revealing the inherent educational phenomena. Through this new perspective, I observed two biology laboratory classes in a high school and analyzed the pattern of teacher-student and student-student interactions. Some meaningful educooperation was found in students' chattering, which has been traditionally considered as merely noise in the classroom, rather than in teacher-student interactions. This study discusses the reasons for these findings in detail and culminates in suggesting ways for accentuating the educational aspect of school laboratory activity.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1251-1264
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• 2018

The systematic and effective design method of a Class-D current-source resonant inverter for use in an induction cooker with zero-ripple line current is presented. The design procedure is based on the principle of the Class-D current-source resonant inverter with a simplified load network model that is a parallel equivalent circuit. An induction load characterization is obtained from a large-signal excitation test-bench based on parallel load network, which is the key to an accurate design for the induction cooker system. Accordingly, the proposed scheme provides a systematic, precise, and feasible solution than the existing design method based on series-parallel load network under low-signal excitation. Moreover, a zero-ripple condition of utility-line input current is naturally preserved without any extra circuit or control. Meanwhile, a differential-mode input electromagnetic interference (EMI) filter can be eliminated, high power quality in utility-line can be obtained, and a standard-recovery diode of bridge-rectifier can be employed. The step-by-step design procedure explained with design example. The devices stress and power loss analysis of induction cooker with a parallel load network under large-signal excitation are described. A 2,500-W laboratory prototype was developed for $220-V_{rms}/50-Hz$ utility-line to verify the theoretical analysis. An efficiency of the prototype is 96% at full load.

• 대한임상검사과학회지
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• 제49권4호
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• pp.477-488
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• 2017

이 연구는 임상병리검사학(또는 임상검사과학, 의학검사과학, 의생명검사과학)에 대한 체계적 인 접근을 하기 위해 임상병리검사학의 정체성과 학문분류체계를 가지고 논의하였다. 임상병리검사학은 한국 연구재단의 학술연구분야분류에 등재되어 있지 않다. 국내에서는 1963년 임상병리검사학과 최초로 신설된 이후 전국에 임상병리검사학과가 52개에 이르고 있다. 학문적 정체성에도 불구하고 제도적으로 임상병리검사학은 전문적 영역을 확보하지 못하고 있는 실정이다. 학술연구분야분류를 보면 물리치료학, 작업치료학, 치위생학은 체계적으로 분류되어 그 학문성을 인정받고 있다. 이 연구는 임상병리검사학의 새로운 학문분류체계이다. 내용 연구는 다음과 같이 요약된다. 임상병리사의 학문은 대분류 의약학, 중분류 임상병리학, 소분류 임상병리검사학에 위치한다. 세분류의 학문용어는 "혈액수혈학, 면역생화학, 미생물기생충학, 유전분자생물학, 조직세포학, 심폐신경생리학"으로 구성한다.

• Molecules and Cells
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• 제19권2호
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• pp.223-227
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• 2005

We have identified TMPRSS6, a novel type 2 transmembrane serine protease. TMPRSS6 possesses all the signature motifs of the family of transmembrane serine proteases (TMPRSSs), including a transmembrane domain, an LDL receptor class A (LDLRA) domain, a scavenger receptor cysteine-rich (SRCR) domain, and a serine protease domain. The substrate specificity of TMPRSS6 is slightly different from those of other TMPRSS family members. Combined with the finding that TMPRSS6 is expressed strongly in the thyroid and weakly in the trachea, this may indicate that TMPRSS6 has a specialized role.

• 대한수학회지
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• 제57권5호
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• pp.1299-1322
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• 2020

We consider closed, star-shaped, admissible hypersurfaces in ℝⁿ⁺¹ expanding along the flow Ẋ = |X|^α-1 F^-β, α ≤ 1, β > 0, and prove that for the case α ≤ 1, β > 0, α + β ≤ 2, this evolution exists for all the time and the evolving hypersurfaces converge smoothly to a round sphere after rescaling. Besides, for the case α ≤ 1, α + β > 2, if furthermore the initial closed hypersurface is strictly convex, then the strict convexity is preserved during the evolution process and the flow blows up at finite time.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.878-883
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• 1990

There have been many approaches to solve the disturbance rejection problem in the control of LTI systems with state independent disturbances or possibly nonlinear state dependent disturbances. From the view point of each actuator, robot manipulators can be modeled as the second class of systems. With this model, M.Nakao et al. [1] introduced a decentralized control scheme based on interference estimation which is simple in its implementation and robust to the coupled dynamics and parameter variations. This paper systematically generalizes the control scheme to arbitrary finite dimensional LTI systems with disturbances. In doing so, we develop a disturbance observer theory for solving the disturbance rejection problem. We also present a discrete version of the theory with discussion of sampling and time-delay effects.

• 대한치과기공학회지
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• 제37권3호
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• pp.157-167
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• 2015

Purpose: This study studied and investigated the oral health behavior of students in the Department of Dental Technology at D College at D City. Methods: A self-administrated survey was conducted by students currently enrolled at the Department of Dental Laboratory Technology at D College (June 4, 2015 ~ June 12, 2015), and 320 copies that were available for statistical processing were statistically analyzed by using the SPSS 19.0 Program. Results: Among the survey respondents, 91.6% had experience of dental treatment. The highest response regarding the frequency of tooth brushing appeared to be 'twice' with 44.7%. The responses regarding the time of tooth brushing appeared to be highest for 'before sleeping' with 65.3%, which was followed by 'after breakfast' with 60.6%. To the question asking which areas are brushed during tooth brushing, the response of 'teeth, gum, and tongue' appeared to be highest with 44.4%. Among the respondents, 64.7% experienced scaling, however, the experience rate for scaling appeared to increase in proportion with the increase of class year (p< .001). Regarding the subjective feel for the importance of oral health and necessity of tooth brushing, the scores appeared to be both 4.56. However, the score appeared to be 3.27 regarding one's subjective perception of one's own oral health condition. Regarding one's subjective oral health knowledge level depending on gender, female students showed a meaningfully lower rate (3.12 points) compared to male students (3.29 points) (p< .05), and depending on class, the knowledge level appeared to be meaningfully higher along with the increase in class year (p< .001). The experience of receiving oral health education appeared to be 78.4%, and 88.8% of the respondents responded that there is need for oral health education, however, the intent to participate in an oral health education program appeared to be 56.6%. Conclusion: As a result of the study, it could be concluded that oral health management behaviors and awareness of the students at the Department of Dental Technology at D University to prevent oral diseases were rather poor.

• 지질공학
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• 제26권1호
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• pp.101-115
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• 2016

관정의 시멘팅 재료로 사용될 수 있는 두 시멘트 물질(KS-1 보통 포틀랜드, Class G)의 물/고체(고체=시멘트) 중량비와 첨가제인 비산재의 부피함량 변화에 따른 이들 물질들의 물리역학적 물성 변화를 파악하기 위해 실내물리역학실험을 실시하였다. KS-1 보통 포틀랜드 시멘트의 경우 물/고체(고체=시멘트) 중량비를 변화시키며, Class G 시멘트의 경우 물/고체(고체=비산재+시멘트)을 고정한 채 비산재:시멘트의 부피비를 변화시키며 시료를 제작하였다. KS-1 보통 포틀랜드 시멘트의 경우 물/고체 중량비가 증가할수록, Class G 시멘트의 경우 비산재의 함량이 증가할수록, 공극률 증가, 밀도감소, 음파속도(P, S파) 감소. 탄성상수(영율, 포아송비) 감소, 압축 및 인장강도 저하, 열전도도 감소, 비열 증가의 경향을 보였다. 또한 구속압(σ₃)의 증가와 비산재 함량의 증가는 재료의 소성파괴거동을 초래하였다. 이 실내실험결과를 이용하여, 여러 주입공 페라미터(케이싱, 시멘트층의 두께, 주입압, 주입공 경사방향 및 경사각, 주입공 심도)등을 변화 시키면서, 시멘트층의 안정성 분석을 실시하였다. 분석결과 낮은 주입압과 경사정 혹은 수평정에서는 시멘트층이 안정하였으나, 다른 조건에서는 시멘트층에서 주로 인장파괴가 관찰 되었다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권7호
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• pp.3309-3315
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• 2016

Helicobacter pylori as the second most common cause of gastric cancer in the world infects approximately half of the developed countries population and 80% of the population living in developing countries. Integrons as genetic reservoirs play major roles in dissemination of antimicrobial resistance genes. To the best of our knowledge, this is the first study to report carriage of class 1 and 2 integrons and associated gene cassettes in H. pylori isolates from Iran. This cross-sectional study was conducted in Tehran among 110 patients with H. pylori infection. Antimicrobial susceptibility testing (AST) for H. pylori strains were assessed by the micro broth dilution method. Class 1 and 2 integrons were detected using PCR. In order to determine gene cassettes, amplified fragments were subjected to DNA sequencing of both amplicon strands. The prevalence of resistance to clarithromycin, metronidazole, clarithromycin, tetracycline, amoxicillin, rifampin, and levofloxacin were 68.2% (n=75), 25.5% (n=28), 24.5% (n=27), 19.1% (n=21), 18.2% (n=20) and 16.4% (n=18), respectively. Frequency of multidrug resistance among H. pylori isolates was 12.7%. Class 2 integron was detected in 50 (45.5%) and class 1 integron in 10 (9.1%) H. pylori isolates. The most predominant gene cassette arrays in class 2 integron-bearing H. pylori were included sat-era-aadA1, dfrA1-sat2-aadA1, blaoxa2 and, aadB whereas common gene cassette arrays in class 1 integron were aadB-aadA1-cmlA6, aacA4, blaoxa2, and catB3. The high frequency of class 2 integron and multidrug resistance in the present study should be considered as a warning for clinicians that continuous surveillance is necessary to prevent the further spread of resistant isolates.