• 접착 및 계면
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• 제3권1호
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• pp.43-51
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• 2002

Advanced adhesive technologies and demanding applications of adhesive joints can no longer be developed successfully by the traditional "trial and error" approach. Appropriate technical solutions require reference to a reliable basis of well-established scientific knowledge about the elementary mechanisms of adhesion (i.e. the 'fundamental adhesion') as they are responsible for the capability of the compound w transmit mechanical force between the adhesive and the substrate surface (i.e. the 'practical adhesion'). Adhesion mechanisms also influence the formation of polymer structure in the adhesive and the resulting macromolecular dynamics in the interphase that is formed in the adhesive near to the substrate. These manifold molecular factors rule the macroscopic behaviour of an adhesive bond line in terms of mechanical and other physical properties as well as in terms of durability. This paper reviews the level of refinement that understanding of fundamental adhesion has achieved up to now.

• Bulletin of the Korean Chemical Society
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• 제34권1호
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• pp.68-74
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• 2013

The surface enhanced Raman spectrum of juglone, a traditional natural dye, has been observed by a custom-built micro-Raman setup. The spectral features of juglone significantly differ from those of lawsone, a structural isomer of juglone; only small red shifts of the double bond stretching bands are observed, and strong SERS bands are observed in the lower frequency regions as well. The DFT computations reveal that juglone coordinated to an $Ag^+$ adatom with $H^+$ release best correlates with the observed vibrational characteristics in the SERS spectrum among the plausible configurations of juglone coordinated to an adatom on the Ag surface, in line with the previously studied lawsone case. The differences in the SERS spectra of juglone and lawsone are attributed to the different locations of the hydroxyl group in the two isomers.

• 전기학회논문지P
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• 제57권4호
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• pp.444-450
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• 2008

There are several ways to bond to building grounding systems for reducing GPR(ground potential rise) and EMI resulting from power system faults or lightning stroke to building. In order to verify effective bonding practice, the GPR and voltage of equipment due to the direct stroke to building are calculated with ATP-EMTP model for transformer, transmission line and MOV(Metal oxide varistor). The simulated model shows a satisfactory accuracy compared with experimental result for the $8/20{\mu}s$ simulated current pulse. It is observed that separate grounding can cause dangerous voltage to the building equipment and the performance of surge protective device can improve when it is installed to the protected equipment in distance as short as possible.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 추계학술대회
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• pp.157-158
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• 2018

본 논문은 3상 AC 모터와 영구동기자석 모터제어를 위한 새로운 1200V, 5A/10A 지능형 전력반도체 모듈(Intelligent Power Module, IPM) 제품을 소개한다. 이 전력 모듈은 DIP(Dual in line)패키지의 DBC(Direct Bond Copper)로 구성되어 있으며 Silicon on Insulator, SOI type의 6 채널 게이트 드라이브와 6개의 IGBT, Diode로 구성되어 있다. 본 논문에서는 1200V, 5A/10A 의 새로운 전력반도체의 전기적 특성 및 드라이빙 퍼포먼스를 소개한다.

• Journal of Welding and Joining
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• 제32권6호
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• pp.1-7
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• 2014

For the resistance spot welds of CR1180 and GA1180 TRIP steels, the weld quality evaluation method using the digitalized X-ray transmission imaging apparatus was investigated in comparison with the crosssectional examination method. In the case of the resistance spot welding of CR1180, three circular regions, such as WZ(white zone), GZ(grey zone) and DZ(dark zone), appeared on X-ray image and they corresponded to the diameters of indentation mark, nugget and corona bond, respectively. The variation of X-ray transmission thickness due to the thickness variation of the weld seemed to be mainly responsible for the formation of those contrasts. The X-ray image contrast formed from the variation of transmission thickness at the outer border line of DZ could also enable the inspections of the notch shape, nonuniformity of the welding pressure and spatter from its sharpness, concentricity and the normal straight line, respectively. The X-ray image of the resistance spot weld of galvannealed GA1180 TRIP steel was very similar to that of CR1180 TRIP steel except the crown shaped outer border line of DZ which was considered to be due to the melting behavior of zinc having the boiling temperature even lower than the melting temperature of steel.

• BMB Reports
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• 제43권4호
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• pp.250-256
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• 2010

Natural phosphodiester bond CpG-DNA that contains immunomodulatory CpG motifs (PO-DNA) upregulates the expression of proinflammatory cytokines and induces an Ag-driven Th1 response in a CG sequence-dependent manner in mice. In humans, only phosphorothioate backbone-modified CpG-DNA (PS-DNA) and not PO-DNA has immunomodulatory activity. In this study, we found that liposome-encapsulated PO-DNA upregulated the expression of human $\beta$-defensin-2 (hBD-2) and major histocompatibility class II molecules (HLA-DRA) in a CG sequence-dependent and liposome- dependent manner in human B cells. Of the three different liposomes, DOTAP has the unique ability to enhance the immunomodulatory activity of PO-DNA. In contrast, HLA-DRA and hBD-2 promoter activation can be induced by liposome-encapsulated PS-DNA in a CG sequence-independent manner, depending on the CpG-DNA species. Our observations demonstrate that, when encapsulated with a proper liposome in the immune system, natural PO-DNA has the potential to be a useful therapy for the regulation of the innate immune response.

• The Journal of Advanced Prosthodontics
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• 제8권5호
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• pp.404-410
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• 2016

PURPOSE. Considering the importance of retention in the success and long-term clinical service of fixed partial dentures (FPDs) as well as the existing controversy regarding the effect of GLUMA desensitizer on the retention of full metal crowns cemented with RelyX U200 self-adhesive cement, this study aimed to assess the effect of GLUMA desensitizer on the retention of full metal crowns cemented using RelyX U200. MATERIALS AND METHODS. In this experimental study, 20 sound human premolars were prepared; a 0.5 mm chamfer finish line was prepared above the cementoenamel junction. The teeth were randomly assigned to two groups: a desensitizer group (n = 10, treated with GLUMA desensitizer) and a control (n = 10, no surface treatment). Full metal crowns were fabricated of base metal alloy and had a ring. All crowns were cemented with RelyX U200 and subjected to retention test by using a universal testing machine. The data were analyzed using SPSS version 20 and independent t-test. RESULTS. The mean tensile bond strength was significantly higher in the GLUMA desensitizer group ($230.63{\pm}63.8N$) compared to the control group ($164.45{\pm}39.3N$) ($P{\leq}.012$). CONCLUSION. GLUMA desensitizer increases the tensile bond strength of RelyX U200 self-adhesive cement to dentin.

• 전기학회논문지
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• 제57권9호
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• pp.1606-1611
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• 2008

Recently, The diagnosis techniques of electric facilities are developed on live line. This paper describes the discharge characteristics of polymer insulator(EPDM A type). Keeping the facilities in good working order, the goal of this paper will provide the information to enable user to easily judge conditions of facilities on the spot. The performance of polymer insulator is assessed from the KS C IEC 60270 and CEA LWIWG-01(96)(Tracking Wheel Test). As the results, UV generation patterns of polymer insulator grow like a jellyfish shape follow the ramping voltage. Discharging UVs are detected at about 31.25% of breakdown voltage. Just then, dimension of UV image is about $0.84cm^{2}$. The dimension of max. UV image is about $297.4cm^{2}$ at $160kV(V_{bd})$. The position of UV generation due to surface discharge of polymer insulator is the center of insulator in the early, then moved the ground side and the last, UV image moved through the junction part of source side. Surface of aged polymer insulator is cracked and faded due to arc. UV absorption spectrum of polymer insulator are appeared the C-H bond of scissoring vib. at $1014cm^{-1}$ and C=O bond of recombination structure. Also, recombined UV absorption peak such as C-H, N-H, and O-H is detected at the $3321cm^{-1}$. Through the paper, there are inspection data which are the relations between surface discharge of polymer insulator and UV detecting image.

• 대한본초학회지
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• 제33권5호
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• pp.19-37
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• 2018

Objectives : Oryeong-san was composed of Alismatis Rhizoma, Atractylodis Rhizoma Alba, Poria Sclerotium, Polyporus, Cinnamomi Cortex, and known to have hundreds of chemical compounds. The aim of this study was to screen chemical compounds constituting Oryeong-san with the drug-likeness and oral bioavailability from the analysis of their physicochemical properties. Methods : A list of chemical compounds of Oryeong-san was obtained from TM-MC(database of medicinal materials and chemical compounds in Northeast Asian traditional medicine). To remove redundant compounds, the SMILES (Simplified Molecular Input Line Entry System) strings of each compound were identified. All of the physicochemical properties for the compounds were calculated using the DruLiTo(Drug Likeness Tool). Drug-likeness was estimated by QED(Quantitative Estimate of Druglikeness) and OB(Oral bioavailability) was checked based on the Veber's rules. Results : A total of 475 compounds were obtained by eliminating duplication among 544 compounds of 5 medicinal materials. Analysis of the physicochemical properties revealed that the most common values were MW(molecular weight) 200~300 g/mol, ALOGP(octanol-water partition coefficient) 1~2, HBA(number of hydrogen bond acceptors) 0~1, HBD(number of hydrogen bond donors) 0, PSA(polar surface area) 0~50 angstrom, ROTB(number of rotatable bonds) 1, AROM(number of aromatic rings) 0, and ALERT(number of structural alerts) 1. QED had 93% of the values between 0.2 and 0.7, and OB had 90% of the value of TRUE. Conclusions : We in this paper screened the candidate active compounds of Oryeong-san using the QED and Veber's rules. In the future, we will use the screening results to analyze the mechanism of Oryeong-san based on systems pharmacology.

• 생명과학회지
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• 제22권4호
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• pp.456-465
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• 2012

유전자 재조합 이형이합체 인간 뼈 형성촉진인자(rhBMP)들은 뼈 재생을 위한 조직공학연구에 중요한 요소들이다. 그러나 실제 뼈 재생에 관한 연구를 수행함에 이들을 이용하는 것은 뼈 형성 촉진인자들이 짧은 반감기를 가지며 비교적 고농도의 단백질을 사용해야 하기 때문에 그만큼 많은 비용이 소요된다는 문제점을 가지고 있다. 이러한 한계를 뛰어넘기 위하여, 본 연구에서는 단백질 전달 서열(PTD)이 융합된 인간 뼈 형성촉진인자 2와 7이 이형이합체 유전자 재조합 단백질(rhBMP2/7-PTD)을 발현하는 세포주를 확립하였다. 이형이합체의 형성은 BMP 2와 BMP 7 단백질 및 PTD 영역의 사이에 각각 4개의 glycine 아미노산 염기서열이 첨가될 수 있도록 하여 각 단백질의 folding이 자유롭도록 디자인하였다. 이렇게 개발된 세포주는 고농도의 rhBMP2/7-PTD을 지속적으로 발현하여 배양액 내로 분비함으로 조직공학용 연구 및 개발에 효율적으로 이용 할 수 있다. 이상의 세포주에서 발현된 rhBMP2/7-PTD 단백질은 뼈 세포분화 유도를 확인 할 수 있는 ALP 활성을 나타냄으로써 뼈 성장촉진 단백질로서 생물학적인 활성을 가지고 있음을 보였다. 본 연구의 결과로 개발된 rhBMP2/7-PTD 형질전환 세포주는 향후 뼈 조직 재생과 같은 연구에 중요하고 효과적인 도구로 이용될 수 있을 것으로 사료된다.