• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2862-2867
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• 2007

The steady non-reacted compressible flow field in a symmetric micro-thruster, which is used for the accurate attitude control of a satellite, is analyzed varying the nozzle pressure ratio (NPR) to investigate the plume characteristics. The nozzle throat diameter is 0.06 inch and the area ratio is 56. The recirculation region is found just behind the normal shock at the several NPRs due to the locally adverse pressure gradient along the nozzle centerline when the environmental pressure is atmospheric. This phenomenon, the cause of flow loss, is similar to the flow behind a blunt body. As NPR increases the location of Mach disk, characteristics of the normal shock, moves downstream and its strength increases. The Mach number distribution appears in a wave-type patter after the normal shock because oblique shocks are reflected on the shock boundaries especially when NPRs are very high.

• 한국의류학회지
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• 제36권5호
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• pp.501-511
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• 2012

This study examines the effect of structural properties of F/W wool knit fabrics for woman's knitwear on the preferences for textile designing through analyzing the relationship among the structural properties, mechanical properties, objective hand measurements, and preferences. The 'knit structure' was determined to be the most important parameter in rating preferences, apart from the 'preference for cardigans'. Consumers preferred washable wool to normal wool when comparing a normal wool knit with a washable wool knit on a 'knit structure' factor. Preferred structural properties showed a similar tendency 'preference for fabric' and the 'preference for cardigans', 'preference for sweaters' and 'preference for vests'. The 'sophisticated/feminine' factor showed a correlation with 'fabric preference' and the texture and sensible images had a similar effect on fabric preferences. In the relationship between objective hand measurements and fabric preferences, the KOSHI value had a negative coefficient and the THV value had a positive correlation with fabric preferences. In conclusion, we found a consumer preference for more flexible fabrics.

• BMB Reports
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• 제53권9호
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• pp.449-452
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• 2020

The inner ear is a complex and delicate structure composed of the cochlea and the vestibular system. To maintain normal auditory function, strict homeostasis of the inner ear is needed. A proper immune response against infection, thus, is crucial. Also, since excessive immune reaction can easily damage the normal architecture within the inner ear, the immune response should be fine regulated. The exact mechanism how the inner ear's immune response, specifically the innate immunity, is regulated was unknown. Recently, we reported a protein selectively localized in the inner ear during bacterial infection, named cochlin, as a possible mediator of such regulation. In this review, the immunological function of cochlin and the mechanism behind its role within inner ear immunity is summarized. Cochlin regulates innate immunity by physically entrapping pathogens within scala tympani and recruiting innate immune cells. Such mechanism enables efficient removal of pathogen while preserving the normal inner ear structure from inflammatory damage.

• 한국의류학회지
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• 제24권3호
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• pp.429-439
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• 2000

This study was aimed to investigate the handle and mechanical properties of silk woven fabrics according to the fabric structure and yarn types 56 male and female students evaluated 16 black specimens with semantic differential scale of 20 hand adjectives. Mechanical parameters such as surface properties, bending properties and compression properties were tested using by KES-FS system. Data were analyzed through factor analysis, pearson correlation coefficient and t-test using PC SAS package. The results were as follows: The hand adjectives were grouped as 4 'surface roughness', 'flexibility', ;sense of thermal', and 'dryness'. 'Surface roughness' was highly sensed at satin fabrics of hard-twist yarn, noil yarn and spun yarn, while it was not at the fabrics of normal satin and twill at all. 'Flexibility' was reverse to 'surface roughness'. Thermal sense was felt highly at satin fabrics of noil-yarn, while low at plain fabrics of normal yarn. 'Dryness' was high at satin fabrics of hard-twist yarn and while it was low at normal satin fabrics. Predicted equations for subjective hand from mechanical properties of fabrics were developed using Stevens's law and stepwise regression and the coefficients of determination were high.

• 한국세라믹학회지
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• 제40권1호
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• pp.104-108
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• 2003

스크래칭 시험(scratching test)을 이용하여 단결정 실리콘의 수직하중에 대한 마찰계수, AE(Acoustic Emission) 신호와 긁힌 자취의 미세균열을 관찰하고 그 결정구조를 분석하였다. 스크래칭 시험은 하중인가속도(loading rate)를 100N/min으로 하고 스크래칭 속도(scratching speed)를 1, 3, 6, 10mm/min의 4가지로 하여 최대 30N이 될 때까지 행하였다. 그 결과, 수직하중 또는 스크래칭 속도가 증가할 때 마찰계수, AE, 균열밀도는 증가하는 경향을 나타내었다. 스크래칭, 자취에 대한 마이크로 라만 분광법을 이용한 결정구조 분석결과, 스크래칭 속도가 느린 조건에서 압력인가에 따른 실리콘의 다이아몬드 구조에서 다른 고압상의 구조로의 상전이 현상을 관찰할 수 있었다.

• 한국동물학회지
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• 제30권3호
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• pp.248-260
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• 1987

In order to investigate the importance of the prospective mesodermal and endodermal blastomeres at 32-cell stage in the anis formation, blastomeres were deleted or transplanted into the ventrovegital site of another normal embryo. The results are as follows: When the dorsomesodermal or dorsoendodermal blastomeres were deleted, there was a substantial developmental lesion in the axis structure. However, when the ventromesodermal or ventroendodermal blastomeres were deleted, the formation of an axis structure was nearly normal. The dorsomesodermal or dorsoendodermal blastomeres which were transplanted into the ventral side of the normal 32-cell embryo caused the formation of a secondary body axis, and the capacity of the second axis induction in the dorsomesodermal blastomeres was a little higher than that in the dorsoendodermal blastomeres. These results imply that both the dorsomesodermal and dorsoendodermal blastomeres are involved in the formation of a set of dorsal body structures during early embryogenesis. As well, in order to investigate the axis inducing capacity in the early cleavage embryos, the dorsovegital blastomeres were transplanted into the ventrovegital site at 4-cell, 8-cell and 16-ceIL stage respectively. As a ruts·fIt, a second body axis was formed. Therefore, it seems that the early cleavage embryo as 4-cell stage dorsal blastomeres contain some informations necessary for the axis formation.

• Nuclear Engineering and Technology
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• 제27권6호
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• pp.888-893
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• 1995

맨봉 배열에 의해 형성되는 부수로를 흐르는 난류 유동장의 구조는 피치 대 봉직경의 비에 따라 변하게 된다. 피치 대 봉직경 비가 큰 경우에는 난류 응력 분포가 관 유동의 분포와 유사하다 그러나 피치 대 봉직경 비가 작은 경우에는 특히 간극 영역에서 난류 특성이 관 유동의 분포와는 달라진다. 완전히 발달된 맨봉 주위의 난류 유동장에서 난류응력과 난류운동에너지 사이의 선형 관계가 개발되었다. 개발된 상관 관계식은 난류 연구에 응용되는 여러 이론적 분석에 연관지어 사용될 수 있다.

• Steel and Composite Structures
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• 제38권5호
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• pp.599-615
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• 2021

The ultimate strength behaviour of sandwich composite beams with J-hooks and normal weight concrete (SCSSBJNs) are studied through two-point loading tests on ten full-scale SCSSBJNs. The test results show that the SCSSBJN with different parameters under two-point loads exhibits three types of failure modes, i.e., flexure, shear, and combined shear and flexure mode. SCSSBJN failed in different failure modes exhibits different load-deflection behaviours, and the main difference of these three types of behaviours exist in their last working stages. The influences of thickness of steel faceplate, shear span ratio, concrete core strength, and spacing of J-hooks on structural behaviours of SCSSBJN are discussed and analysed. These test results show that the failure mode of SCSSBJN was sensitive to the thickness of steel faceplate, shear span ratio, and concrete core strength. Theoretical models are developed to estimate the cracking, yielding, and ultimate bending resistance of SCSSBJN as well as its transverse cross-sectional shear resistance. The validations of predictions by these theoretical models proved that they are capable of estimating strengths of novel SCSSBJNs.

• Earthquakes and Structures
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• 제24권1호
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• pp.53-64
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• 2023

Earth fissures with several kilometers will inevitably approach or cross the metro line, significantly threatening the safety of the underground structure in the earth fissure site. However, the influence of the earth fissure site's amplification effect on the metro station's dynamic response is still unclear. A representative earth fissure in Xi'an was taken as an example to establish a numerical model of a metro station in the earth fissure site. The dynamic response characteristics of the metro stations at different distances from the earth fissure under various seismic waves were calculated. The results show that the existence of the earth fissure significantly amplifies the dynamic response of the nearby underground structures. The responses of the axial force, shear force, bending moment, normal stress, horizontal displacement, inter-story drift, and relative slip of the metro station were all amplified within a specific influence range. The amplification effect increases with the seismic wave intensity. The amplification effect caused by the earth fissure has relatively weak impacts on the axial shear, shear force, bending movement, normal stress, and horizontal movement; slightly larger impacts on the inter-story drift and acceleration; and a significant impact on the relative slip. The influence ranges of the axial force and normal stress are approximately 20 m. The influence ranges of the acceleration and inter-story drift can reach 30 m. Therefore, the seismic fortification level of the underground structure in the earth fissure site needs to be improved.

• Journal of Microbiology and Biotechnology
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• 제33권9호
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• pp.1213-1227
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• 2023

Fetal growth restriction (FGR) is a prevalent obstetric condition. This study aimed to investigate the role of Toll-like receptor 9 (TLR9) in regulating the inflammatory response and gut microbiota structure in FGR. An FGR animal model was established in rats, and ODN1668 and hydroxychloroquine (HCQ) were administered. Changes in gut microbiota structure were assessed using 16S rRNA sequencing, and fecal microbiota transplantation (FMT) was conducted. HTR-8/Svneo cells were treated with ODN1668 and HCQ to evaluate cell growth. Histopathological analysis was performed, and relative factor levels were measured. The results showed that FGR rats exhibited elevated levels of TLR9 and myeloid differentiating primary response gene 88 (MyD88). In vitro experiments demonstrated that TLR9 inhibited trophoblast cell proliferation and invasion. TLR9 upregulated lipopolysaccharide (LPS), LPS-binding protein (LBP), interleukin (IL)-1β and tumor necrosis factor (TNF)-α while downregulating IL-10. TLR9 activated the TARF3-TBK1-IRF3 signaling pathway. In vivo experiments showed HCQ reduced inflammation in FGR rats, and the relative cytokine expression followed a similar trend to that observed in vitro. TLR9 stimulated neutrophil activation. HCQ in FGR rats resulted in changes in the abundance of Eubacterium_coprostanoligenes_group at the family level and the abundance of Eubacterium_coprostanoligenes_group and Bacteroides at the genus level. TLR9 and associated inflammatory factors were correlated with Bacteroides, Prevotella, Streptococcus, and Prevotellaceae_Ga6A1_group. FMT from FGR rats interfered with the therapeutic effects of HCQ. In conclusion, our findings suggest that TLR9 regulates the inflammatory response and gut microbiota structure in FGR, providing new insights into the pathogenesis of FGR and suggesting potential therapeutic interventions.