• 한국건축시공학회지
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• 제21권1호
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• pp.87-95
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• 2021

본 연구에서는 현재 건설신기술로 지정된 복합계방수공법 7개사(A~G)를 대상으로 KS F 2622:멤브레인 방수층 성능평가 시험방법 중 현장 적용조건과 유사성이 큰 평가항목을 선정하여 평가한 결과, 모든 시험체가 기본 물성평가에서 KS 기준을 상회하는 성능을 확보했음에도 불구하고, 내피로(균열 거동) 시험을 제외한 방수성(수밀성) 시험, 처짐 저항성 시험, 부풂 저항성 시험에서 점착 도막 계열로 이루어진 공법의 접합부와 수직부 등 취약부위의 현장품질 성능을 확보하기 어려운 것으로 확인하였다.

• 복식문화연구
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• 제31권5호
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• pp.692-704
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• 2023

This study analyzed 214 sports knee braces found on Chinese websites between October 2022 and November 2022 to assess product type (impact protection material, fastening method, and protection method), material composition, size, weight, and main characteristics. The product type was further categorized according to (1) use of hard guard and soft guard protection method; (2) cover type, strap type, and slip-on type fastening method; and (3) pressure type and support type protection method. It also noted the physical shock protection materials used, including foam (EVA or polyurethane) attached to joints as a buffer material and plastic (TPU or PP) that protects the user's knee from external impacts. The study found that the materials that primarily comprise sports knee braces are a combination of nylon, polyester, and neoprene. Additionally, it found that most sports knee braces available on the market are available in three sizes based on knee circumference: M (35-38cm), L (38-41cm), and XL (41-44cm), while some products are available in one size only. Furthermore, the majority of the 214 products studied weighed 200g, followed by 1,000g. Finally, in terms of product characteristics, many sports knee braces utilize ring-shaped silicone pads to distribute the load pressure on the knees or incorporate sturdy adhesive velcro to improve knee stability.

• 한국가구학회지
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• 제16권1호
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• pp.1-8
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• 2005

This experiment was carried out to investigate the gluing characteristics of poly vinyl acetate emulsion adhesive(PVAc) on the Cryptomeria japonica laminated boards. This sample trees are major planting species and have been planted in southern district for a long time. The optimum gluing conditions for laminated board were summarized as follows; the amount of spreading glue, assembly time, clamping pressure, and clamping time for PVAc resin were $200g/m^2$, 10min., $5kg/cm^2$, and 6hrs., respectively, and the relative formulae between extension ratio(x) and block shear strength(y) was $y=-9.6x+85.2(R^2=0.95)$.

• Advances in aircraft and spacecraft science
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• 제4권6호
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• pp.729-744
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• 2017

This investigation highlights rationale of electrically conductive nano adhesives for its essential application for Electromagnetic Interference (EMI) Shielding in satellites and Lightning Strike Protection in aircrafts. Carbon Nano Fibres (CNF) were functionalized by electroless process using Tollen's reagent and by Plasma Enhanced Chemical Vapour Deposition (PECVD) process by depositing silver on CNF. Different weight percentage of CNF and silver coated CNF were reinforced into the epoxy resin hardener system. Scanning Electron Microscopy (SEM) micrographs clearly show the presence of CNF in the epoxy matrix, thus giving enough evidence to show that dispersion is uniform. Transmission Electron Microscopy (TEM) studies reveal that there is uniform deposition of silver on CNF resulting in significant improvement in interfacial adhesion with epoxy matrix. There is a considerable increase in thermal stability of the conductive nano adhesive demonstrated by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Four probe conductivity meters clearly shows a substantial increase in the electrical conductivity of silver coated CNF-epoxy composite compared to non-coated CNF-epoxy composite. Tensile test results clearly show that there is a significant increase in the tensile strength of silver coated CNF-composites compared to non-coated CNF-epoxy composites. Consequently, this technology is highly desirable for satellites and EMI Shielding and will open a new dimension in space research.

• 한국산림과학회지
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• 제105권4호
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• pp.505-509
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• 2016

본 연구는 현재 수목관리 현장에서 사용 중인 상처도포제의 유효성을 확인하기 위해 실시하였다. 티오파네이트메틸 도포제(상표명: 톱신페스트)는 은행나무, 느티나무, 왕벚나무에서, 라놀린은 느티나무와 왕벚나무에서, 테부코나졸 도포제(상표명: 실바코)는 왕벚나무에서 각각 무처리구 대비 유의하게 높은 상처유합률을 나타냈다. 페트롤리움젤리(상표명: 바셀린)는 은행나무, 느티나무, 왕벚나무 등 소나무를 제외한 전 수종에서, 인체 무독성 접착제(상표명: 오공본드)는 느티나무에서 각각 무처리구보다 유의하게 낮은 상처유합률을 보였다. 특히 바셀린을 처리한 느티나무와 왕벚나무 상처부위에서는 형성층이 괴사되어 상처가 확대되는 피해가 발생하였다. 소나무는 수지 유출로 인해 상처도포제 처리효과가 나타나지 않았다.

• 대한치과교정학회지
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• 제42권1호
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• pp.17-22
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• 2012

Objective: To study and compare the effects of different demineralization-inhibition methods on the shear bond strength (SBS) and fracture mode of an adhesive used to bond orthodontic brackets to demineralized enamel surfaces. Methods: Eighty freshly extracted, human maxillary premolars were divided into 4 equal groups and demineralized over the course of 21 days. Brackets were bonded to the demineralized enamel of teeth in Group 1. In Group 2, bonding was performed following resin infiltration ($ICON^{(R)}$, DMG, Hamburg, Germany). Before bonding, pre-treatment with acidulated phosphate fluoride (APF) or solutions containing casein phosphopeptide-amorphous calcium phosphate with 2% neutral sodium fluoride (CPP-ACP/wF) was performed in Groups 3 and 4, respectively. The SBS values of the brackets were measured and recorded following mechanical shearing of the bracket from the tooth surface. The adhesive remnant index (ARI) scores were determined aft er the brackets failed. Statistical comparisons were performed using one-way ANOVA, Tukey's post-tests, and G-tests. Results: Significant differences were found in some of the intergroup comparisons of the SBS values (F = 39.287, p < 0.001). No significant differences were found between the values for the APF-gel and control groups, whereas significantly higher SBS values were recorded for the resin-infiltrated and CPP-ACP/wF-treated groups. The ARI scores were also significantly different among the 4 groups (p < 0.001). Conclusions: Tooth surfaces exposed to resin infiltration and CPP-ACP/wF application showed higher debonding forces than the untreated, demineralized surfaces.

• Restorative Dentistry and Endodontics
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• 제40권1호
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• pp.68-74
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• 2015

Objectives: This study examined the effects of additional acid etching on the dentin bond strength of one-step self-etch adhesives with different compositions and pH. The effect of ethanol wetting on etched dentin bond strength of self-etch adhesives was also evaluated. Materials and Methods: Forty-two human permanent molars were classified into 21 groups according to the adhesive types (Clearfil SE Bond [SE, control]; G-aenial Bond [GB]; Xeno V [XV]; Beauti Bond [BB]; Adper Easy Bond [AE]; Single Bond Universal [SU]; All Bond Universal [AU]), and the dentin conditioning methods. Composite resins were placed on the dentin surfaces, and the teeth were sectioned. The microtensile bond strength was measured, and the failure mode of the fractured specimens was examined. The data were analyzed statistically using two-way ANOVA and Duncan's post hoc test. Results: In GB, XV and SE ($pH{\leq}2$), the bond strength was decreased significantly when the dentin was etched (p < 0.05). In BB, AE and SU (pH 2.4 - 2.7), additional etching did not affect the bond strength (p > 0.05). In AU (pH = 3.2), additional etching increased the bond strength significantly (p < 0.05). When adhesives were applied to the acid etched dentin with ethanol-wet bonding, the bond strength was significantly higher than that of the no ethanol-wet bonding groups, and the incidence of cohesive failure was increased. Conclusions: The effect of additional acid etching on the dentin bond strength was influenced by the pH of one-step self-etch adhesives. Ethanol wetting on etched dentin could create a stronger bonding performance of one-step self-etch adhesives for acid etched dentin.

• 대한치과보철학회지
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• 제29권3호
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• pp.33-41
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• 1991

Cermic has been widely used because of its excellent esthetics and strength. The recently introduced castable ceramic system is regarded as the more esthetic and biocompatible restorative material. The purpose of this study was to compare the shear bond strength of Dicer & G-Cera porcelain laminate veneer according to the type of cement and surface treatment and to observe the surface of bonding failure with SEM. Total forty disks(3.5mm $diam.\times2.0mm$ thickness) were prepared. Forty extracted human maxillary central incisor teeth were stored in saline solution. Ten teeth were bonded to Dicer specimen with Dicer ZPC cement and ten teeth were bonded with Dicer resin cement. Ten silicoated G-Cera specimen and ten non-silicoated G-Cera specimen were bonded to teeth with G-Cera resin cement. Bonded units were mounted in a plastic tube with hard stone and stored in a humidor at $37^{\circ}C$ for 24 hours. Shear bond strength was measured by Instron Universal Testing Machine (Model 1125) and all the specimen were observed with SEM(JEOL, JSM-T2000)and modes of failure were recorded. The obtained results were as follows: 1. The mean shear bond strength of Dicer bonded with Dicer resin cement was 11.62 MPa and that bonded with Dicor ZPC cement was 0.88 MPa : Shear bond strength of Dicer bonded with Dicer resin cement was significantly increased(P<0.05). 2. The mean shear bond strength of silicoated G-Cera was 13.10 MPa and that of non silicoated G-Cera was 10.93 MPa : Shear bond strength of silicoated G-Cera was not significantly increased (P>0.05). 3. Shear bond strength of Dicer and G-Cera porcelain laminate veneer was not significantly different (P>0.05). 4. In observation of bond failure with SEM, Dicer bonded with Dicer ZPC cement exhibited adhesive failure. Dicer bonded with Dicer resin cement and silicoated and non silicoated G-Cera exhibited cohesive failure.

• Tribology and Lubricants
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• 제30권4호
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• pp.224-233
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• 2014

We prepared polyester-polyamines to improve the effect of carbon black dispersibility for use in thermal transfer ink, and synthesized polymeric dispersing agents by two-step reactions. In the first step, we made polyester by polycondensing 1,6-hexanediol and adipic acid. The resulting polymers had carboxylic acid, which was linked with polyamine via an acid-base reaction. We then characterized the polyester-polyamine structure by NMR spectroscopy and Fourier transform infrared spectroscopy (FT-IR). We also determined the basic characterizations such as total acid numbers (TAN) (5.0-67.5 mgKOH/g), hydroxyl values (27.1-67.5 mgKOH/g), and molar masses ($M_n=1.6-8.4kg\;mol^{-1}$) for the polyester and total base numbers (TBN) (15.3-57.1 mgKOH/g), hydroxyl values (33.0-79.8 mgKOH/g), and nitrogen contents (1.02-3.48%) for the polyester-polyamine polymers. We thus prepared thermal transfer ink using carbon blacks and the polyester-polyamine dispersing agents, and evaluated the resulting mixtures for printability, adhesive force, storage stability, ink appearance, ink gloss, and processability. These mixtures showed significant dispersibility for carbon black in the ink. Thus, we concluded that the dispersibility of the polymeric materials depended on the polyamine structure and the hydrophilicity-hydrophobicity distribution of the polymeric dispersants.

• 대한환경공학회지
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• 제33권10호
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• pp.717-722
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• 2011

현재, melamine은 레진, 내화제, 접착제, 라미네이트 등 우리 생활에 다양하게 사용되고 있다. 그로 인해 melamine이 포함된 폐수의 수계 유입 또한 증가하고 있다. EU안전지침서의 GHS에는 melamine을 암 유발 가능성이 있는 물질로 구분하고 있다. 하지만 아직까지 melamine에 대한 독성연구는 진행 중이며 어떤 영향을 주는지 아직까지 밝혀진 사실이 적다. 본 연구에서는 한강과 주변하천의 melamine 오염 정도를 HPLC/UV를 이용하여 오염 정도를 파악하였다. 그리고 활성탄을 이용한 흡착실험 및 모델링에 관한 연구를 하였다. 우선 한강수계 중 상대적으로 상류에 있는 팔당댐 근교와 그보다 하류지역인 뚝섬유원지에서 동일한 시료를 3개씩 채수하였고 한강에 유입되는 하천 중 홍릉천, 왕숙천, 청계천에서 동일하게 시료를 채수하여 정제 후 melamine 농도를 측정하였다. 그 결과 팔당댐 근교의 시료에서는 melamine이 검출되지 않았으며 그보다 상대적으로 하류인 뚝섬유원지에서는 $0.312{\mu}g/L$농도가 검출되었다. 왕숙천에는 $0.578{\mu}g/L$로 가장 높았으며 청계천과 홍릉천은 각 $0.197{\mu}g/L$, $0.325{\mu}g/L$로 검출되었다. 전체적으로 낮은 농도지만 대부분의 지점에서 melamine의 검출을 확인할 수 있었다. 1970년대에는 melamine 생산량이 200,000 ton에서 최근에는 1,400,000 ton으로 계속적인 사용의 증가로 수계오염은 심화될 것으로 보인다. 활성탄을 이용한 흡착 실험에서는 활성탄 크기에 따라 melamine흡착에 약간의 차이를 보였으나 파과모델과 어느 정도 일치함을 보였다.