• 제목/요약/키워드: critical means

검색결과 972건 처리시간 0.027초

초임계 이산화탄소 염색 및 가공 기술 (Supercritical CO2 Dyeing and Finishing Technology - A Review)

  • 이교영;채주원;이상오;김삼수;이재웅
    • 한국염색가공학회지
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    • 제31권1호
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    • pp.48-64
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    • 2019
  • With evolution in the production environment of the textile industry, the need for non-water-based dyeing technologies and eco-friendly process facilities in the dyeing and processing stages has increased. In recent years, supercritical fluid dyes have been developed and commercialized in Europe, centering on this demand. However, so far, such dyes have been mainly applied in the processing of PET fibers. Basic research has mainly involved investigation of dyeing by supercritical carbon dioxide or solubility of such dyes, and more in-depth research should be continuously carried out. In this review, we describe the types and characteristics of supercritical fluids that exhibit specific properties at pressures and temperatures over the critical point. In addition, the state of the art in the dyeing and processing technology using supercritical fluids and associated, processing problems, environmental regulation, and wastewater treatment issues are described in detail. We hope this review can contribute to the supercritical fluid technology being further developed as an environment friendly dyeing processing method. Furthermore, we expect that the technique can be used as a means of ensuring different, high-quality dyed products.

Performance Improvement in Single-Phase Electric Spring Control

  • Wang, Qingsong;Zuo, Wujian;Cheng, Ming;Deng, Fujin;Buja, Giuseppe
    • Journal of Power Electronics
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    • 제19권3호
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    • pp.784-793
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    • 2019
  • Two objectives can be pursued simultaneously with the ${\delta}$ control of a single-phase electric spring (ES). These objectives are the stabilization of the voltage across the critical load (CL) of a power system, and the achievement of a specific functionality similar to the pure compensation of reactive power or the correction of the power factor. However, existing control systems implementing the ${\delta}$ control do not cope with non-ideal operating conditions, such as line voltage distortions, and exhibit a somewhat sluggish regulation of the CL voltage. In an effort to improve both the steady-state and transient performances of an ES power system, this paper proposes implementing the ${\delta}$ control by means of a control system built up on the repetitive control and assisted by state feedback with pole assignment. This paper starts by analyzing the dynamics of an ES power system in terms of its poles and zeros. After that, a reduced second-order model of the dynamics is formulated to avoid a notch filter in the pole assignment. A repetitive control for an ES power system is then designed to meet the two above mentioned objectives. Experimental tests carried out on a laboratory setup demonstrate the effectiveness of the proposed control system in significantly improving the ES power system performance, while reaching the two objectives. In particular, the tests outline the large mitigation of harmonics in the CL voltage under line voltage distortions and its fast stabilization action.

Mitophagy Improves Ethanol Tolerance in Yeast: Regulation by Mitochondrial Reactive Oxygen Species in Saccharomyces cerevisiae

  • Jing, Hongjuan;Liu, Huanhuan;Lu, Zhang;Cui, liuqing;Tan, Xiaorong
    • Journal of Microbiology and Biotechnology
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    • 제30권12호
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    • pp.1876-1884
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    • 2020
  • Ethanol often accumulates during the process of wine fermentation, and mitophagy has critical role in ethanol output. However, the relationship between mitophagy and ethanol stress is still unclear. In this study, the expression of ATG11 and ATG32 genes exposed to ethanol stress was accessed by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). The result indicated that ethanol stress induced expression of the ATG11 and ATG32 genes. The colony sizes and the alcohol yield of atg11 and atg32 were also smaller and lower than those of wild type strain under ethanol whereas the mortality of mutants is higher. Furthermore, compared with wild type, the membrane integrity and the mitochondrial membrane potential of atg11 and atg32 exhibited greater damage following ethanol stress. In addition, a greater proportion of mutant cells were arrested at the G1/G0 cell cycle. There was more aggregation of peroxide hydrogen (H2O2) and superoxide anion (O2•-) in mutants. These changes in H2O2 and O2•- in yeasts were altered by reductants or inhibitors of scavenging enzyme by means of regulating the expression of ATG11 and ATG32 genes. Inhibitors of the mitochondrial electron transport chain (mtETC) also increased production of H2O2 and O2•- by enhancing expression of the ATG11 and ATG32 genes. Further results showed that activator or inhibitor of autophagy also activated or inhibited mitophagy by altering production of H2O2 and O2•. Therefore, ethanol stress induces mitophagy which improves yeast the tolerance to ethanol and the level of mitophagy during ethanol stress is regulated by ROS derived from mtETC.

한국 산업계에서 사고조사 수행 시 사고조사자의 관점에 관한 연구 (Incident Investigator's Perspectives on Incident Investigations Conducted in Korea Industry)

  • 권재범;권영국
    • 한국안전학회지
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    • 제36권2호
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    • pp.58-67
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    • 2021
  • Incident investigation is regarded as a means to improve safety performance. For the prevention of industrial accidents, measures such as providing safety education, enhancing management interest and participation, establishing a safety management system, and conducting inspection of the work site are necessary. In particular, accident investigation activities, which are an important element of safety management, help to prevent similar accidents, thereby minimizing damage and enhancing work safety. They are critical for understanding business-related incidents and the vulnerabilities and opportunities associated with them. Therefore, it is clear that accident investigation activities are important for accident prevention. The primary focus of many incident investigation processes is on identifying the cause of an event. While considerable research has been conducted on potential accident investigation tools there has been little research on including the views and experiences of practitioners in the accident investigation process. In this study, a questionnaire survey was conducted among safety managers in the domestic manufacturing/construction industry to understand the practice of accident investigation. The investigation pertained to companies' accident investigation systems, the competence of investigators, and the identification and recommendations of the cause of accidents. From the analysis results of accident investigations, investigators' competence, the difficulty level of investigations, and the root causes of accidents were identified from the viewpoint of the participants of the accident investigations. In particular, the development of standardized and simple accident investigation methods and their dissemination to companies were found to be necessary for activating the root cause of accidents. Based on this, it can be used as basic data for the development of root cause analysis investigation techniques that are easily applicable to organizations.

괴병다속담(怪病多屬痰) 이론에 대한 비판적 (Critical Review on Theory of "Eccentric Diseases are Due to Phlegm")

  • 배성진;최준용;김기봉;하기태
    • 동의생리병리학회지
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    • 제34권6호
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    • pp.279-284
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    • 2020
  • The theory of "eccentric diseases are generally due to phlegm (怪病多屬痰)" means that phlegm is a major cause for intractable diseases including cerebrovascular accident, depression, insanity, and shock from strange things or evil sprint. It has been a key foundation for the diagnosis and treatment of phlegm in traditional Korean medicine. However, the origin of the theory is not clear and controversial. In this study, we critically reviewed the origin and developing process of the theory in the viewpoints of philology and pathology in Korean medicine. Wang Yin-Jun (王隱 君) did not claim that eccentric diseases are generally due to phlegm in Taidingyangshengzhu-lun (泰定養生主論). The miscitation by following medical literature caused the misunderstanding in the meaning of Taidingyangshengzhu-lun, that phlegm can cause variable symptoms and signs. In the Ming dynasty, some poor medical doctors had tended to diagnose any difficult case as phlegm syndrome and to use Kuntan-huan (滾痰丸) as a standard herbal formula for treating phlegm syndrome. However, the tendency to categorize delicate cases easily to phlegm syndrome is not desirable. Besides, the tendency to use Kuntan-huan as a basic formula for the phlegm syndrome might cause diverse and severe adverse effects. Thus, we cannot accept the theory of eccentric diseases is generally due to phlegm without a doubt. In conclusion, this theory might be a valuable aphorism in terms of considering the possibility of the secondary pathologic factors including phlegm and blood stasis which should be considered first in case of intractable diseases.

블렌디드 노벨 엔지니어링이 창의적 문제해결력 향상에 미치는 영향 (An Effects of Blended Novel Engineering on Improving Creative Problem-Solving Ability)

  • 홍기천;이우진;유준희
    • 산업융합연구
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    • 제19권1호
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    • pp.27-32
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    • 2021
  • 노벨 엔지니어링은 독서를 통하여 문제를 찾아내고, 이를 공학적인 방법으로 해결해보는 융합수업모형이다. 이제까지의 노벨 엔지니어링 연구는 온전히 대면으로 진행되어왔다. 그러나 COVID-19 사태 이후를 대비하여 온라인과 오프라인 수업을 병행한 블렌디드 러닝의 연구가 매우 필요하다. 그래서 본 연구에서는 블렌디드 노벨 엔지니어링 수업이 초등학생들의 창의적 문제해결력 향상에 미치는 영향에 대해서 연구하였다. 연구 결과, 이 수업이 자기 확신 및 독립성, 확산적 사고, 비판적 사고, 동기적 요소 요인에서 기존의 문제해결 프로젝트 수업보다 더 높은 효과가 있다는 것이 증명되었다. 이는 블렌디드 노벨 엔지니어링 수업이 2015 개정 교육과정에서 제시한 역량 중심 수업을 위해서 매우 효과적이라는 것을 의미한다. 이 연구로 인하여 코로나 이후 시대에 블렌디드 노벨 엔지니어링이 학교 현장에 확산되어 정착될 수 있기를 기대한다.

유방암세포에서 LATS1/2 활성에 의한 당귀 추출물의 항암효과 (Anti-tumorigenic Effects of Angelica gigase Nakai Extract on MBA-MB-231 through Regulating Lats1/2 Activation)

  • 김초롱;김남빈;정한솔;신유수;모정순
    • 동의생리병리학회지
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    • 제34권4호
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    • pp.177-183
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    • 2020
  • The Hippo-YAP signaling pathway is critical for cell proliferation, survival, and self-renewal in both Drosophila and mammals. Disorder of Hippo-YAP pathway leads to tumor development, progression and poor prognosis in various cancers. YAP/TAZ are the key downstream effectors of the Hippo pathway and they can be inhibited through LATS1/2, core kinases in the Hippo pathway, mediated phosphorylation. In this study, we investigated the effect of Angelica gigas Nakai extract (AGNE) on Hippo-YAP/TAZ pathway. First, ANGE induced YAP/TAZ phosphorylation and dissociation of the YAP/TAZ-TEAD transcription complex. By qRT-PCR, we found that ANGE inhibits the expression of YAP/TAZ-TEAD target gene, CTGF and CYR61. In addition, the transcriptional activity of YAP/TAZ was not suppressed significantly in LATS1/2 double-knockout (DKO) cells by ANGE compared to LATS1/2 wild-type (WT) cells, which means AGNE inhibits YAP/TAZ signaling through direct action on LATS1/2. Further, it was confirmed that AGNE-induced activation of LATS1/2 inhibited the migration potential of the vector-expressing cells by suppressing YAP/TAZ activity. The reduced migration potential was restored in active YAP-TEAD expressing cells. Taken together, the results of this study indicate that ANGE downregulates YAP/TAZ signaling in cells through the activation of LATS1/2.

뉴미디어 시대 속 '참교육' 콘텐츠와 현대인의 의식구조 (Contents of 'true education' in the Era of New Media and the Consciousness Structure of Modern People)

  • 김세연
    • 한국콘텐츠학회논문지
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    • 제22권4호
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    • pp.468-478
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    • 2022
  • 전교조 핵심 이념이었던 '참교육'은 뉴미디어 시대의 자장 안에서 재전유된다. 젊은층을 중심으로 활발히 사용되는 이 단어는 '사회적 비난의 대상이 되는 사람 대한 응징'을 뜻한다. 최근 인터넷에서 흔히 볼 수 있는 '참교육 콘텐츠'의 특징으로는 첫째, '단편화' 경향을 보인다는 점이다. 참교육 콘텐츠들은 분량이 짧고, 내용이 매우 지엽적이다. 이는 총체성이 사라지고 작은 이야기들을 소비하는 포스트모던 사회의 특징을 반영한다. 둘째, 선악을 가르는 기준이 지극히 '자의적'이라는 것이다. 기존 권선징악 서사들은 사랑·배려·평화 등 어느 정도 보편적인 가치를 지니고 있었던 데 비해, 참교육 콘텐츠는 지극히 편협한 시선으로 선악을 구분한다. 자의적 기준에 대한 정당성을 얻기 위해 택하는 방법은 공공의 분노를 부추기는 것이다. 셋째, '유머'가 가미되어 있다는 점이다. 여기서 유머는 혐오의 정서와 결합하며, 사람들의 비판의식을 약화시킨다는 문제를 야기한다.

Identification of Adaptive Traits Facilitating the Mechanized Harvesting of Adzuki Bean (Vigna angularis)

  • Xiaohan Wang;Yu-Mi Choi;Sukyeung Lee;Myoung-Jae Shin;Jung Yoon Yi;Kebede Taye Desta;Hyemyeong Yoon
    • 한국자원식물학회지
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    • 제35권6호
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    • pp.785-795
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    • 2022
  • Traditional germplasms are unsuitable for mechanized production, limiting adzuki bean production. The creation of cultivars that can be harvested by mechanized means is an urgent task for breeders. The bottom pod height (BPH), lodging resistance, and synchronous maturing of adzuki beans are critical factors for the reduction of losses due to mechanized harvesting. In this study, 14 traits of 806 adzuki bean accessions were analyzed. All growth stages and the yield, lodging score, and synchronous maturing correlated negatively with the BPH. These negative correlations reflect the increased difficulty of breeding to simultaneously satisfy the needs for no lodging, high synchronous maturing rates, BPHs > 10 cm, and high yield. We screened three germplasms with no lodging, high synchronous maturing rates, and BPHs > 10 cm that were used as mechanization-adapted breeding material for crossing with high-yield cultivars. Agronomic trait diversity in adzuki beans was also examined in this study. Principal component and cluster analyses were conducted for 806 germplasms resulting in three clusters with the yield and three growth stage traits serving as the main discriminating factors. Cluster 1 included high-yield germplasms with the number of pods per plant and the number of seeds per pod being the major discriminant factors. Cluster 2 included germplasms with long growth periods and large 100-seed weights while cluster 3 contained germplasms with high BPHs. In general, the characteristics that make mechanical harvesting feasible and those assessed in this study could be utilized to choose and enhance adzuki beans production.

FATIGUE DESIGN OF BUTT-WELDED TUBULAR JOINTS

  • Kim, D. S.;S. Nho;F. Kopp
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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    • pp.127-132
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    • 2002
  • Recent deepwater offshore structures in Gulf of Mexico utilize butt welded tubular joints. Application of welded tubular joint includes tendons, production risers, and steel catenary risers. Fatigue life assessment of these joints becomes more critical because the structures to which they are attached are allowed to undergo cyclic and sometimes large displacements around an anchored position. Estimating the fatigue behavior of these tubular members in the design stage is generally conducted by using S-N curves specified in the codes and standards. Applying the stress concentration factor of the welded structure to S-N approach often results in very conservative assessment because the stress field acting on the tubular has a non-uniform distribution through the thickness. Fracture mechanics and fitness for service (FFS) technology have been applied in the design of the catenary risers. This technology enables the engineer to establish proper requirements on weld quality and inspection acceptance criteria to assure satisfactory structural integrity during its design life. It also provides guidance on proper design curves to be used and a methodology for accounting for the effects of non-uniform stress distribution through the wall thickness. An attempt was made to develop set of S-N curves based on fracture mechanics approach by considering non-uniform stress distribution and a threshold stress intensity factor. Series of S-N curves generated from this approach were compared to the existing S-N curves. For flat plate butt joint, the S-N curve generated from fracture mechanics matches with the IIW class 100 curve when initial crack depth was 0.5 mm (0.02"). Similar comparison with API X′ was made for tubular joint.. These initial crack depths are larger than the limits of inspection by current Non-destructive examination (NDE) means, such as Automatic Ultrasonic Inspection (AUT). Thus a safe approach can be taken by specifying acceptance criteria that are close to limits of sizing capability of the selected NDE method. The comparison illustrates conservatism built into the S-N design curve.

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