80년도 춘이총회 연구발표 논문초록

Sigrist,Lukas,Rhee,Bosung 한국화학공학회 1980 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.18 No.3

Measurements of mass transfer toward a gas sparged electrode with and without superimposed electrolyte flow will be reported. The mass transfer coefficient, measured by the well known limiting current method, depends mainly on the gas voidage fraction, irrespective of the fluid flow velocities. The system shows a striking analogy with turbulent natalur convection and the results can be represented formally by the same dimensionless correlation replacing the Grashof number by a modified Archimedes number.

Electrochemical Engineering a Science of Its Own

Sigrist,Lukas 한국화학공학회 1981 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.19 No.4

역사적으로 볼 때, 지난 20년 동안 전기화학공학은 그 자체 하나의 기술과학으로 발전하였다. 최적화와 경제성 산출의 원리는 대안 또는 최적방법 등에 대한 정량적인 분석을 하기 위하여 물질적인 것들을 공통사용수단인 돈으로 환원시키는 것을 수반한다. 맥동전류에 의한 금속도금기술의 개발이 연구되어지고 있다. 전극설계의 발달결과 전기화학공정은 폐수처리와 같은 실제 이용에도 사용할 수 있는 매우 경제적인 좋은 공정이 되어졌다. A glance at the historical development shows that electrochemical engineering became a technical science of its own through the last decades. Principles of optimization and economic evaluation are involved reducing the physical laws to a common denominator, money, in order to perform a quantitative analysis of alternative and optimal routes. Scientific investigations open a window on future techniques of metalplating by pulsating current. Developments in cell design made electrochemical processing quite attractive and competitive to conventional routes, e.g. for waste water treatment.

연구발표논문초록

Lukas Sigrist 한국화학공학회 1980 추계총회초록집 Vol.- No.-

Vocational Education of Skilled Workers for Industrial Chemistry, Germany - Switzerland

Lukas Sigrist 대한공업교육학회 1982 대한공업교육학회지 Vol.7 No.2

숙련 기술자들의 수준에서 두 가지 직업이 공업화학을 위해 구분된다. 하나는 화학실험실 작업으로 규정되고, 다른 하나는 제조과정으로 규정된다. 직업교육은 도제살이에 의해서 행해진다. 즉, 다시말하면 실재 작업장소에서 실재훈련이나, 실업계 학교들에서 행해지는 이론적이고 일반적인 교육을 말한다. 직업교육은 법률과 규칙으로 규정되고 있다. On the level of skilled workers, two vocations are distinguished for industrial chemistry, one oriented to the chemical laboratory work, the other to the manufacturing process. The vocational education is done by apprenticeship, i.e. the practical training on the real working place, the theoretical and general education at vocatonal schools. The vocational education is legislated by laws and regulations.

Chemical Engineer, a Tentative Definition

Lukas Sigrist 대한공업교육학회 1983 대한공업교육학회지 Vol.8 No.1

To the Mass Transfer at Vertical Gas Sparged Electrodes

Lukas Sigrist,Bosung Rhee 한국화학공학회 1980 춘계총회초록집 Vol.- No.-

Topological Aspects and Transport Properties of Edge States in the Multi-band Superconductor Sr2RuO4

Yoshiki Imai,Katsunori Wakabayashi,Manfred Sigrist 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.3

Motivated by the spin-triplet superconductor Sr2RuO4, we investigate the edge states by using atwo-band tight-binding model with interorbital hybridization and spin-orbit coupling. In particularwe focus on the topological aspects and the transport properties in the chiral spin-triplet superconductingphase. The Fermi surfaces correspond to the ones of Sr2RuO4 where the and the bandshave hole- and electron-like characters, respectively. Although a full quasiparticle excitation gapis present in the bulk system, gapless edge states appear and affect both the spin and the chargecurrents. We study the interplay between electron- and hole-like particles in the formation of theseedge states and edge currents. Topologically the two bands compensate for each other such that theedge state is not topologically protected. The repulsive interaction yields a spin polarization nearthe edges and lifts the degeneracy of the subgap edge states. The net spontaneous magnetizationgenerated through both the edge charge current and the spin polarization may be small due to cancelingeffects. The lifting of the spin degeneracy could likely be detected by quasiparticle tunnelingfor the surface density of states.

Fracture incidence of Reciproc instruments during root canal retreatment performed by postgraduate students: a cross-sectional retrospective clinical study

Ruivo Liliana Machado,Rios Marcos de Azevedo,Villela Alexandre Mascarenhas,Martin Alexandre Sigrist de,Kato Augusto Shoji,Pelegrine Rina Andrea,Barbosa Ana Flávia Almeida,Silva Emmanuel João Nogueira 대한치과보존학회 2021 Restorative Dentistry & Endodontics Vol.46 No.4

Objectives To evaluate the fracture incidence of Reciproc R25 instruments (VDW) used during non-surgical root canal retreatments performed by students in a postgraduate endodontic program. Materials and Methods From the analysis of clinical record cards and periapical radiographs of root canal retreatments performed by postgraduate students using the Reciproc R25, a total of 1,016 teeth (2,544 root canals) were selected. The instruments were discarded after a single use. The general incidence of instrument fractures and its frequency was analyzed considering the group of teeth and the root thirds where the fractures occurred. Statistical analysis was performed using the χ2 test (p < 0.01). Results Seven instruments were separated during the procedures. The percentage of fracture in relation to the number of instrumented canals was 0.27% and 0.68% in relation to the number of instrumented teeth. Four fractures occurred in maxillary molars, 1 in a mandibular molar, 1 in a mandibular premolar and 1 in a maxillary incisor. A greater number of fractures was observed in molars when compared with the number of fractures observed in the other dental groups (p < 0.01). Considering all of the instrument fractures, 71.43% were located in the apical third and 28.57% in the middle third (p < 0.01). One instrument fragment was removed, one bypassed, while in 5 cases, the instrument fragment remained inside the root canal. Conclusions The use of Reciproc R25 instruments in root canal retreatments carried out by postgraduate students was associated with a low incidence of fractures. Objectives To evaluate the fracture incidence of Reciproc R25 instruments (VDW) used during non-surgical root canal retreatments performed by students in a postgraduate endodontic program. Materials and Methods From the analysis of clinical record cards and periapical radiographs of root canal retreatments performed by postgraduate students using the Reciproc R25, a total of 1,016 teeth (2,544 root canals) were selected. The instruments were discarded after a single use. The general incidence of instrument fractures and its frequency was analyzed considering the group of teeth and the root thirds where the fractures occurred. Statistical analysis was performed using the χ2 test (p < 0.01). Results Seven instruments were separated during the procedures. The percentage of fracture in relation to the number of instrumented canals was 0.27% and 0.68% in relation to the number of instrumented teeth. Four fractures occurred in maxillary molars, 1 in a mandibular molar, 1 in a mandibular premolar and 1 in a maxillary incisor. A greater number of fractures was observed in molars when compared with the number of fractures observed in the other dental groups (p < 0.01). Considering all of the instrument fractures, 71.43% were located in the apical third and 28.57% in the middle third (p < 0.01). One instrument fragment was removed, one bypassed, while in 5 cases, the instrument fragment remained inside the root canal. Conclusions The use of Reciproc R25 instruments in root canal retreatments carried out by postgraduate students was associated with a low incidence of fractures.

工業敎育大學 機械科와 化工科의 敎育課題 開發을 위한 韓獨 共同 現場調査硏究

金基會,李輔成,李來烈,周赫鍾,朴鍾鎬,Bode, R.,Winkler, H.,Sigrist, L.,Echtermeyer, K.,Petzinna, C. 충남대학교 공업교육연구소 1982 論文集 Vol.5 No.1

In 1950s, until the end of the Korean War, economy of the Republic of Korea has been strongly oriented to agriculture. From 1960s to 1970s, four times successive Economic Development Plan has changed its economic aspects to the labor oriented export industry one. This change is connected with big problem. One of these problems which is important for the success is education in the field of technology. Then, College of Industrial Education at Chungnam National University is assigned being Koreas first, only and unique institution to educate the teachers for Technical High Schools, thus, to contribute to a prosperous development of the nation skilled manpower in a cardinal point. The main goal of this field study is to gather useful materials and informations, relevant and meaningful for the development of curricula measurments within the field of vocational technical education. This includes not only pre-vocational education in Technical High School but also the training of technical teachers at C.I.E.. After analysing the informations and results of this field study we can find quite a lot of possible recommendations for persons and institutions involved in vocational-technical education. But we will express only a certain amount of them, 1) Put higher emphasis on basic vocational qualifications ! 2) Provide realistic perspectives towards the world of work ! 3) Link theory and practice in vocational-technical education ! 4) Develop an active qualification strategy in schools ! 5) Develop thoroughly appropriate curricula ! 6) Reduce the number of students in classes ! 7) Adapt the equipment of schools towards educational goals ! 8) Integrate vocational practice into technical education !

Restoration of T-box–containing protein expressed in T cells protects against allergen-induced asthma

Park, Jung Won,Min, Hyun Jung,Sohn, Jung Ho,Kim, Joo Young,Hong, Jeong Ho,Sigrist, Kirsten S.,Glimcher, Laurie H.,Hwang, Eun Sook Elsevier 2009 The journal of allergy and clinical immunology Vol.123 No.2

<P><B>Background</B></P><P>A T<SUB>H</SUB>1-specific transcription factor, T-box–containing protein expressed in T cells (T-bet), controls the production of both T<SUB>H</SUB>1 and T<SUB>H</SUB>2 cytokines in T<SUB>H</SUB> cell differentiation by means of distinct mechanisms. T-bet–deficient mice overproduce T<SUB>H</SUB>2 cytokines and have spontaneous airway inflammation.</P><P><B>Objectives</B></P><P>We tested whether T-bet overexpression could protect against the development or progression of asthma.</P><P><B>Methods</B></P><P>We generated a T cell–specific and inducible line of T-bet–transgenic mice on a T-bet–deficient genetic background and used it to study the function of T-bet in an ovalbumin (OVA)–induced asthma model.</P><P><B>Results</B></P><P>Induction of T-bet in a T cell–specific manner in an OVA model of asthma concomitant with OVA injection prevented airway hyperresponsiveness, eosinophilic and lymphocytic inflammation, and IL-5 and IL-13 production in bronchoalveolar lavage fluid and also reduced serum IgE and T<SUB>H</SUB>2 cytokine production by peripheral T cells. Even when T-bet expression was induced during later stages of asthma progression, T-bet overexpression still attenuated airway hyperresponsiveness and goblet cell hyperplasia, as well as T<SUB>H</SUB>2 cytokine production.</P><P><B>Conclusions</B></P><P>Our results suggest that T-bet expression in T cells can prevent the initiation of airway inflammation and progression of chronic inflammation and might be extrapolated to human asthma.</P>