• Title/Summary/Keyword: 부식성

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Detorque force and surface change of coated abutment screw after repeated closing and opening (코팅된 지대주 나사의 반복 착탈 후 풀림력과 표면변화에 대한 연구)

  • Jang, Jong-Suk;Kim, Hee-Jung;Chung, Chae-Heon
    • The Journal of Korean Academy of Prosthodontics
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    • v.46 no.5
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    • pp.500-510
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    • 2008
  • Statement of problem: Recently researches about WC/C (Tungsten Carbide/Carbon) or TiN (Titanium Nitride) coating on abutment screws are going on. It decreases friction coefficient, resistance against corrosion and withdrawal of physical fragility when the coating is applied to the metal surfaces. It is reported that coated abutment screws improved abrasion, adaptability and detorque force. Purpose: This study is about the effects of coated abutment screws on loosening of screw and for the purpose of solving the loosening phenomenon of abutment screws which is clinical problem. Material and methods: Detorque force and surface changes are compared when 10 times of repeated closing and opening are applied to both uncoated titanium abutment screws (Group A) and coated abutment screws with WC/C (Group B) and TiN (Group C). Each group was made up of 10 abutment screws. Results: 1. Before repeated closing and opening, Somewhat rough surface with regular direction was observed in Group A. Coated granules were observed in group B and group C and overall coated layer appeared in regular and smooth form. 2. Before repeated closing and opening, The coated surface showed bigger and thicker size of coated granules in Group C than Group B. 3. After repeated closing and opening, abrasion and deformation of abutment screw surface was observed in Group A and Group B. Exfoliation phenomenon was observed in Group B. 4. Group A showed biggest range of decrease when the weight changes of abutment screws were measured before and after repeated closing and opening. Group C showed less weight changes than Group B but there was no statistical difference between two groups. 5. Group B and Group C showed higher average detorque force than Group A and there was statistical difference. 6. Group A showed more prominent decrease tendency of average detorque force than Group B and Group C. Conclusion: Coated abutment screws with WC/C or TiN did not show prominent surface changes than uncoated titanium abutment screws even though they were repeatedly used. And they showed excellent resistance against friction and high detorque force. Thus it is considered that adaptation of WC/C or TiN coating on abutment screws will improve the screw loosening problem.

Oxide Films Formed on Hot-Dip Aluminized Steel by Plasma Electrolytic Oxidation and Their Films Growth Stages (플라즈마 전해 산화법에 의해 용융알루미늄도금 강판 상 형성한 산화층과 그 성장 과정)

  • Choe, In-Hye;Kim, Chang-Min;Park, Jun-Mu;Park, Jae-Hyeok;Hwang, Seong-Hwa;Lee, Myeong-Hun
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2017.05a
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    • pp.165-165
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    • 2017
  • 지난 수 십 년 동안, 전 세계적으로 자원의 소비가 급격히 증가하게 되면서 최근 자원 고갈은 물론 환경오염이 커다란 이슈로 문제가 되고 있다. 이에 따라 재료 관련 분야에 있어서는 보다 효율적이고 친환경적인 방법으로 자원을 활용해야 된다는 필요성이 대두되었고 이와 같은 관점에서 목적하는 성분이 우수하고 환경 친화적인 표면처리 재료 개발연구가 활발하게 진행되고 있는 실정이다. 그 중 플라즈마 전해 산화(Plasma Electrolytic Oxidation, PEO)는 알루미늄, 마그네슘 등의 경금속의 경도를 향상시키고 높은 내마모성, 내식성을 갖게 하는 표면처리로써 그 관심이 증가하고 있다. 이 플라즈마 전해 산화는 일반적으로 공정비용 대비 효과적이고 환경 친화적이며 코팅 성능 면에서 우수하다고 알려져 있다. 이러한 고유한 특성으로 인해 플라즈마 전해 산화 코팅은 최근 몇 년 동안 기계, 자동차, 우주항공, 의학 및 전기 산업 등의 분야에서 그 적용이 점차 증가하고 있는 상황이다. 한편, 플라즈마 전해 산화 코팅을 하는 모재들의 경우 부동태 산화피막을 용이하게 형성할 수 있는 특성의 모재에 한정되고 있어서 그 응용확대에 한계가 있는 것이 사실이다. 따라서 본 연구에서는 플라즈마 전해 산화법을 사용하여 용융알루미늄도금 강판 상에 산화피막 형성을 시도하였다. 전원공급 장치의 양극은 전해질 속에 잠겨있는 작동전극에 연결하고 음극은 대전극 역할을 하는 스테인레스강 전해질 용기에 연결되었다. 전해질은 Sodium Aluminate 및 기타 첨가제를 함유한 것을 사용하였고 온도는 열교환기를 사용하여 $30^{\circ}C$ 이하로 유지되었다. 또한 여기서 전류밀도는 $5{\sim}10A/dm^2$, 실험 주파수는 700Hz, Duty cycle은 30 및 90%의 각 조건에서 공정처리 시간을 각각 30분 및 60분 동안 진행하였다. 이와 같은 조건에서 형성한 막들에 대해서는 주사형전자현미경(SEM)을 이용하여 코팅 막의 표면 및 단면의 모폴로지를 관찰하였음은 물론 EDS 및 XRD 측정을 통하여 원소조성분포 및 결정구조를 각각 분석하였다. 또한 이 코팅 막들에 대한 내식성은 5% 염수분무 환경 중 노출시험(Salt spray test), 3% NaCl 용액에서의 침지 시험 및 전기화학적 동전위 양극분극(Potentiodynamic Polarization) 시험을 진행하여 평가하였다. 이상의 실험결과에 의하면, 제작조건별 플라즈마 전해 산화 코팅 막의 모폴로지 및 결정구조가 상이하게 나타나는 것을 알 수 있었다. 코팅 막의 모폴로지 관찰 결과, 공정 시간에 비례하여 표면에 존재하는 원형 기공의 수는 감소하였으나 그 크기가 커지고 크레이터의 직경 또한 커진 것이 확인되었다. 이 기공은 마이크로 방전에 의해 형성된다고 알려져 있는데 공정 시간이 증가함에 따라 코팅 두께가 점차 증가하여 마이크로 방전의 빈도수가 줄어들고 그 강도는 증가하게 되어 기공 크기가 증가한 것으로 사료된다. 또한 공정시간이 긴 시편에서 표면에 크랙이 다수 존재하는 것으로 확인되었다. 이것은 방전에 의해 고온이 된 소재가 차가운 전해질과 만나게 되어 생긴 큰 온도구배로 인해 강한 열응력이 발생하여 균열을 초래한 것으로 보인다. 조성원소 분석 결과 원형 기공 주변의 크레이터 영역에는 알루미늄이 풍부하였으며 그 주변에 결절상을 갖는 구조에서는 전해질 성분의 원소가 포함되어 있는 것이 확인되었다. 이러한 코팅 막의 표면 특성은 내식성에 영향을 주게 된 원인으로 사료된다. 동전위 분극측정 결과에 의하면 플라즈마 전해 산화 공정 시간이 길어질수록 부식전류밀도가 증가하였다. 이것은 공정시간이 길어짐에 따라 강한 방전이 발생하여 기공의 크기가 증가하고 크랙이 발생하게 되면서 내식성이 저하된 것으로 판단된다. 종합적으로 재료특성 분석 및 내식성 평가를 분석한 결과, 플라즈마 전해 산화의 공정 시간이 너무 길게 되면 오히려 내식성은 저하되는 것이 확인되었다. 이상의 연구를 통하여 고내식 특성을 갖는 플라즈마 전해 산화 막의 유효성을 확인하였으며 용융알루미늄강판 상에 실시한 플라즈마 전해 산화 처리에 대한 기초적인 응용 지침을 제시할 수 있을 것으로 사료된다.

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Studies on the Compositional Change of Composts During Mushroom Cultivation (양송이 재배(栽培)에 따른 재배상퇴비(栽培床堆肥)의 성분변화(成分變化)에 관(關)한 연구(硏究))

  • Namgung, Hee
    • Applied Biological Chemistry
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    • v.18 no.4
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    • pp.203-218
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    • 1975
  • In order to investigate the compositional change oil composts during the growing of cultivated mushroom (Agaricus bisporus), composts and mushrooms during the period of filling to ending under commercial conditions were subjected to chemical analyses. The results are summarized as follows and the mechanism of composting for mushroom cultivation was proposed. 1) The temperature change of growing bed and room was observed and the yield of mushroom for each cropping time was recorded to get $15.6kg/m^2$ in total crops. 2) Composts after filling showed pH 8.2 which dropped to 6.4 after casing and continued so up to ending. 3) On the dry weight basis of composts, crude ash increased whereas total nitrogen, ether extract and crude fibre decreased gradually to bring about the lowering of organic matter. 4) Total nitrogen of composts decreased gradually and more insoluble nitrogen was lost than soluble nitrogen. The C/N ratio of composts was initially 21 which was gradually lowered to 16. 5) The losses of ${\alpha}-cellulose$, pentosan and lignin in composts were 87%, 75%, and 60%, respectively, in which ${\alpha}-cellulose$ decreased markedly after casing. 6) Free reducing sugars of composts increased continuously. Gradually increased free amino acids till second cropping decreased again thereafter. Composts at the filling stage contained alanine, glutamic acid, glycine and serine in which glycine decreased markedly whereas proline increased remarkably upon mushroom cultivation. 7) Among minerals of composts, phosphorus and zinc tended to decrease, potassium and copper tended to increase anti sodium showed no marked change. 8) In comparison of mushrooms from different cropping time with respect to proximate composition, minerals, free reducing sugars and amino acids, no marked difference was observed. However, a little higher values were observed in crude fat, free reducing sugars and sodium content for early crops and in free amino acids and phosphorus content for late crops. Twelve free amino acids including alanine, serine, threonine, and glutamic acid were detected in the cultivated mushroom. 9) According to above experimental results, it was possible to support the mechanism of compositing that the formation of ammonia and decomposition of carbohydrates by mesophiles are followed by protein biosynthesis, formation of microbial bodies and nitrogen-rich lignin humus complex by thermophiles, thus supplying necessary nutrients for mushroom growth, along with residual carbohydrates.

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재래닭 생산물의 소비형태에 관한 조사연구

  • 한성욱
    • Proceedings of the Korea Society of Poultry Science Conference
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    • 1998.04a
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    • pp.51-86
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    • 1998
  • $\bigcirc$ 재래닭 생산물의 소비 및 구매형태 등에 대한 조사에서 종합적인 결론은 최종 소비자의 응답자는 총 2,250명이었으며 연령, 성별, 직업, 거주지, 주거형태, 가족수, 소득분포등이 비교적 다양하게 분포되어 있다. 판매업소의 특성은 지역별, 매장면적, 업주연령, 성별, 경력등에서 매장위치는 약 60%가 농촌이고 관광지 21.3%, 도시 19.0%순이였으며 매장 면적은 10-30평이 66.9%, 경력은 3년이하 27.4%, 3-5년 22.7%, 5-10년 22.2%였다. $\bigcirc$ 재래닭고기의 소비형태에서 육류선호도는 쇠고기, 돼지고기, 닭고기 순이였으며 재래닭고기의 소비형태에서 전체 응답자의 64.4%가 먹어본 경험이 있었다. 주로 섭취시기는 74.5%가 여름철에 식구들과 같이 회식할 때 식사대용이나 부식용으로 섭취하였다. 소비자가 재래닭고기를 좋아하는 이유는 고기가 쫄깃쫄깃하여 씹는맛과 지방이 적으며 단백한 맛 때문에 독특해서 좋아한다고 하였으며, 싫어하는 이유는 너무 질기고 고기의 양이 너무 적다는 의견이 많았다. 선호하는 요리방법은 백숙, 삼계탕이었고 좋아하는 부위는 역시 다리부위였다. 재래닭고기의 섭취량에 대하여는 1회에 2인이 1마리를 먹는다가 36.4%, 3인이 1마리 31.8%로서 68.2%가 2-3인이 1마리를 먹는다고 하였으며, 가족구성원 중에는 가장이 제일 선호하는 것으로 나타났다. $\bigcirc$ 음식점에서 판매되는 요리한 재래닭의 1마리 가격에 대한 의견은 84.5%가 20,000원정도면 부담이 없이 먹겠다고 하였다. $\bigcirc$ 재래닭의 구입행동에서 구입주체는 주부였으며, 구입장소는 농.축협의 슈퍼와 정육점이었고 백화점과 재래닭 사육장에서 직접구입도 하고 있었다. 구입 동기는 가족들이 좋아하고 영양가를 생각한다가 62%였으며 구입정보는 주위사람의 권유로 구입하고 있었다. $\bigcirc$ 구입할 때 중점적으로 살펴보는 사항은 신선도와 순수재래종 여부, 위생상태였다. 한편 소비자가 언제나 구입할 수 없다는 의견이 85.2%나 되어 원활한 공급과 시장조성이 아직 정착되지 않고 있었다. $\bigcirc$ 현재 유통되고 있는 재래종닭은 소비자 대부분이 잡종으로 인식하고 있었으며, 재래종과 일반육계와의 구별은 깃털색, 피부색, 정강이색등 외관상으로 구별하고 있었다. 체중에 대한 반응은 너무 작다는 의견이었고, 식품으로의 인식도는 비교적 고급식품으로 인식하고 있다. $\bigcirc$ 재래종닭고기의 브랜드화에 대한 견해는 젊고 소득이 높은 계층에서 브랜드화의 필요성을 강조하고 있다. $\bigcirc$ 재래종달걀의 소비형태는 대부분의 소비자가 좋아하였으나 아직 먹어보지 못한 응답자가 많았다. 재래종달걀의 맛에 대해서는 고소하고 독특하여 차별성을 느끼고 있었다. $\bigcirc$ 재래종달걀의 구입장소는 계란판매점(축협.농협), 슈퍼, 백화점, 재래닭 사육 농장등 다양하였으며 포장단위는 10개를 가장 선호하였고, 포장재료는 종이, 플라스틱, 짚의 순으로 좋아하였다. $\bigcirc$ 달걀의 가격은 200원정도를 적정하다고 하였으며, 크기는 (평균 52g)는 가장 적당하다고 인식하고 있으며, 난각색은 대부분의 응답자가 갈색을 선호하였다. $\bigcirc$ 재래종달걀의 구입시 애로사항은 믿을수 없고, 구입장소를 몰라서, 값이 싸다 등이었고, 앞으로 신뢰할 수 있고 위생적인 생산 및 유통체계가 확립될 경우 더 많이 소비하겠다는 의견이었다. $\bigcirc$ 재래닭 판매업소(식당)의 판매형태는 66.7%인 대부분의 업소가 잡종과 개량종 유색닭을 판매하고 있었으며, 1개 업소에서 1일 판매수수는 5-10수의 영세한 판매형태였고, 계절적으로는 여름철에 대부분을 판매하였다. $\bigcirc$ 식당에서 판매하는 재래닭고기의 요리 종류는 주로 백숙이었고, 삼계탕, 닭볶음도 있었으며, 요리된 재래닭 1마리 가격은 20,000원 이상이었으며, 20,000원이하로 판매하는 잡종이 많았다. $\bigcirc$ 재래닭 판매업소에서 재래닭을 구입하는 방법은 재래닭 사육농장에서 1회에 수십마리 구입하여 판매업소의 간이 사육장에서 기르면서 판매하는 업소가 49.6%, 도계된 재래닭을 구입하여 판매하는 업소 26.9%, 직접 재래닭을 사육하면서도 도계하여 판매하는 업소가 21.7%였다. 판매업소에서의 재래닭 사육기간은 90일 이상이었으며 대부분의 업주는 야산에서 방사한 것을 좋게 생각하고 있었다.

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Screening of the Optimum Filter Media in the Constructed Wetland Systems through Phosphorus Adsorption Capacities (인의 흡착능 평가를 통한 인공습지 하수처리 시스템의 여재 선발)

  • Lee, Hong-Jae;Seo, Dong-Cheol;Cho, Ju-Sik;Heo, Jong-Soo
    • Korean Journal of Environmental Agriculture
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    • v.22 no.2
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    • pp.148-152
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    • 2003
  • The phosphorus(P) adsorption capacities of various filter media were investigated in relation to the size and types of fitter media to screen the optimum condition. The objective of this study was to evaluate the constructed wetland longevity by improving P adsorption capacity. The maximum P adsorption capacities of filter media A($4{\sim}10\;mm$), B($2{\sim}4\;mm$) and C($0.1{\sim}2\;mm$) were 8, 10 and 22 mg/kg, respectively, showing those increased as the filter media size decreased. Among the experimental media, the optimum filter media size was $0.1{\sim}2\;mm$. When the filter Medium was supplemented with organic materials which were piled up and decayed in the constructed wetland, the P adsorption capacity was significantly enhanced Under the conditions of optimum fitter media size, the respective Maximum P adsorption capacities of filter media C when supplemented with Ca, Mg, Al and Fe were higher than that of filter media C. However the addition of Ca, Mg, Al and Fe to constructed wetland were not recommended because of the possibility of their secondary pollution. The maximum P adsorption capacity of filter media C was 22 mg/kg, but this was increased to 36 mg/kg when filter media C was supplemented with 2% oyster shell.

Heating Efficiency of Difference Heat Collection Methods for Greenhouse (유리온실의 태양열 집열방법별 집열효과)

  • 최영하;이재한;권준국;박동금;이한철
    • Journal of Bio-Environment Control
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    • v.9 no.3
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    • pp.166-170
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    • 2000
  • Three methods for heat collection, which were the flat solar collector, two fan with radiator, and square pipe method, were studied to sue efficiently solar energy in the three different glasshouses for two years. The flat plate solar collector method was made use of the commercial solar collector with collection area of 24$m^2$, the method of two fans with radiators collected solar energy at the top of the glasshouse. An thermal storage tank was constructed underneath in teach glasshouses. When an area of 1,000$m^2$ was heated to the minimum temperature of 9$^{\circ}C$, the decrease rate of heating fuel for the flat plate solar collector, the fan attached radiator and the square pipe methods were 7%, 19% and 28% respectively. The flat plate solar collector method, which could be heated approximately 40-50$m^2$, was currently used by most of the farmer. Under the condition, the decrease rate of annual heating fuel was 14% which was not better for an economic annual heating fuel. If the fan with radiator method was operated, the use of installation and maintenance were required. So, it could not be good economic efficiency of solar heating. The heating efficiency of the square pipe method was relatively better thant those of the flat plate solar collector or the fan attached radiator. Since the cost of materials and its installation of the use of square pipe method was lower than any other method. However, corrosion of the pipe, greater shade in the greenhouse and strength against the square pipe were problems that should be overcome in the square pipe method.

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THE EFFECT OF C-FACTOR AND VOLUME ON MICROLEAKAGE OF COMPOSITE RESIN RESTORATIONS WITH ENAMEL MARGINS (법랑질 변연으로 이루어진 복합레진 수복물의 체적과 C-factor가 미세누출에 미치는 영향)

  • Koo, Bong-Joo;Shin, Dong-Hoon
    • Restorative Dentistry and Endodontics
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    • v.31 no.6
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    • pp.452-459
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    • 2006
  • Competition will usually develop between the opposing walls as the restorative resin shrinks during polymerization. Magnitude of this phenomenon may be depended upon cavity configuration and volume. The purpose of this sturdy was to evaluate the effect of cavity configuration and volume on microleakage of composite resin restoration that has margins on the enamel site only. The labial enamel of forty bovine teeth was ground using a model trimmer to expose a flat enamel surface. Four groups with cylindrical cavities were defined, according to volume and configuration factor(Depth x Diameter / C-factor) - Group I : 1.5 mm ${\times}$ 2.0 mm / 4.0, Group II : 1.5 mm ${\times}$ 6.0 mm / 2.0, Group III : 2.Omm ${\times}$ 1.72 mm / 5.62, Group IV : 2.0 mm ${\times}$ 5.23 mm / 2.54. After treating with fifth-generation one-bottle adhesive - BC Plus$^{TM}$ (Vericom, AnYang, Korea), cavities were bulk flted with microhybrid composite resin - Denfill$^{TM}$ (Vericom). Teeth were stored in distilled water for one day at room temperature and were finished and polished with Sof-Lex system. Specimens were thermocycled 500 times between 5$^{\circ}$C and 55$^{\circ}$C for 30 second at each temperature. Teeth were isolated with two layers of nail varnish except the restoration surface and 1 mm surrounding margins. Electrical conductivity (${\mu}$A) was recorded in distilled water by electrochemical method. Microleakage scores were compared and analyzed using two-way ANOVA at 95% level. The results were as follows: 1. Small cavity volume showed lower microleakage score than large one, however, there was no statistically significant difference. 2. There was no relationship between cavity configuration and microleakage. Factors of cavity configuration and volume did not affect on microleakage of resin restorations with enamel margins only.

Uplift Capacity of Wood Pile for Greenhouse Foundation (온실 기초용 나무말뚝의 인발저항력 검토)

  • Yun, Sung Wook;Choi, Man Kwon;Lee, Si Young;Yu, Chan;Yoon, Yong Cheol
    • Journal of Bio-Environment Control
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    • v.24 no.2
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    • pp.123-127
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    • 2015
  • Wood piles are rarely used in the construction of a greenhouse in Korea, but they are relatively more often used in other countries, such as the Netherlands. There are several advantages associated with wood piles: they are more cost-effective, less time-consuming, and more ecofriendly than the steel pipes (SPs) and pre-stressed highstrength (PHC) piles. However, one of the limiting conditions is that they have to be installed below the groundwater level to prevent decay. Since the groundwater levels are generally high in the reclaimed lands in Korea, wood piles are expected to be used often as reinforcements for foundations of greenhouses in these areas. In this study, we measured the uplift capacities of wood piles through in-situ uplift capacity tests with an aim to provide basic design data for wood pile foundations. In order to test their applicability, we then compared these experimentally measured ultimate uplift capacities with the ones calculated through some of the existing theoretical equations. The wood piles used in the loading tests were made of softwood (pine wood), and the tests were performed using piles with different diameters (∅25cm and ∅30cm) and embedded depths (1m, 3m, and 5m). The test results revealed that the uplift capacity of the wood piles showed a clear linearly increasing tendency in proportion to the embedded depth, with the ultimate uplift capacities for the diameters 25cm and 30cm being 9.38 and 10.56tf, respectively, at the embedded depth of 5m; thus demonstrating uplift capacities of ${\geq}9tf$. The comparison between the actually measured values of the uplift capacity and the ones calculated through equations revealed that the latter, which were obtained using the ${\alpha}$ method, were generally in an approximate agreement with the in-situ measured values.

Effects of conditions for anodization and cyclic precalcification treatments on surface characteristics and bioactivity (양극산화와 석회화 순환처리 조건이 타이타늄 박판의 표면특성 및 생체활성에 미치는 영향)

  • Jang, Yong-Seok;Lee, Kang-Gyu;Jeon, Woo-Yong;Han, A-Lum;Lim, Chung-Ha;Lee, Min-Ho;Bae, Tae-Sung
    • Korean Journal of Dental Materials
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    • v.45 no.4
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    • pp.243-256
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    • 2018
  • The purpose of this study was to investigate the effects of the anodization and cyclic calcification treatment on the surface characteristic and bioactivity of the titanium thin sheet in order to obtain basic data for the production of bioactive titanium membrane. A $30{\times}20{\times}0.08mm$ titanium sheets were prepared, and then they were pickled for 10 seconds in the solution which was mixed with $HNO_3:HF:H_2O$ in a ratio of 12: 7: 81. The $TiO_2$ nanotube layer was formed to increase the specific surface area of the titanium, and then the cyclic calcification treatment was performed to induce precipitation of hydroxiapatite by improvement of the bioactivity. The corrosion resistance test, wettability test and immersion test in simulated body solution were conducted to investigate the effect of these surface treatments. The nanotubes formed by the anodization treatment have a dense structure in which small diameter tubes are formed between relatively large diameter tubes, and their inside was hollow and the outer walls were coupled to each other. The hydroxyapatite precipitates were well combined on the nanotubes by the penetration into the nanotube layer by successive cyclic calcification treatment, and the precipitation of hydroxyapatite tended to increase proportionally after immersion in simulated body solution as the number of cycles increased. In conclusion, it was confirmed that induction of precipitation of hydroxyapatite by cyclic calcification treatment after forming the nanotube $TiO_2$ nanotube layer on the surface of the titanium membrane can contribute to improvement of bioactivity.

Technological Diversities Observed in Bronze Objects of the Late Goryo Period - Case Study on the Bronze Bowls Excavated from the Burial Complex at Deobu-gol in Goyang - (고려 말 청동용기에 적용된 제작기술의 다양성 연구 - 고양 더부골 고분군 출토 청동용기를 중심으로 -)

  • Jeon, Ik Hwan;Lee, Jae Sung;Park, Jang Sik
    • Korean Journal of Heritage: History & Science
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    • v.46 no.1
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    • pp.208-227
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    • 2013
  • Twenty-seven bronze bowls excavated from the Goryo burial complex at Deobu-gol were examined for their microstructure and chemical composition to characterize the bronze technology practiced by commoners at the time. Results showed that the objects examined can be classified into four groups: 1) objects forged out of Cu-near 22%Sn alloys and then quenched; 2) objects cast from Cu-below 10% Sn alloys containing lead; 3) objects cast from Cu-10%~20% Sn alloys containing lead and then quenched; 4) objects forged out of Cu-10~20% Sn alloys containing lead and then quenched. This study revealed that the fabrication technique as determined by alloy compositions plays an important role in bronze technology. The use of lead was clearly associated with the selection of quenching temperatures, the character of inclusions and the color characteristics of bronze surfaces. It was found that the objects containing lead were quenched at temperatures of $520^{\circ}{\sim}586^{\circ}C$ while those without lead were quenched at the range of $586^{\circ}{\sim}799^{\circ}C$. The presence of selenium in impurity inclusions was detected only in alloys containing lead, suggesting that the raw materials, Cu and Sn, used in making the lead-free alloys for the first group were carefully selected from those smelted using ores without lead contamination. Furthermore, the addition of lead was found to have significant effects on the color characteristics of the surface of bronze alloys when they are subjected to corrosion during interment. In leaded alloys, corrosion turns the surface light green or dark green while in unleaded alloys, corrosion turns the surface dark brown or black. It was found that in fabrication, the wall thickness of the bronze bowls varies depending on the application of quenching; most of the quenched objects have walls 1mm thick or below while those without quenching have walls 1mm thick or above. Fabrication techniques in bronze making usually reflect social environments of a community. It is likely that in the late Goryo period, experiencing lack of skilled bronze workers, the increased demand for bronze was met in two ways; by the use of chief lead instead of expensive tin and by the use of casting suitable for mass production. The above results show that the Goryo bronze workers tried to overcome such a resource-limited environment through technological innovations as apparent in the use of varying fabrication techniques for different alloys. Recently, numerous bronze objects are excavated and available for investigation. This study shows that with the use of proper analytical techniques they can serve as a valuable source of information required for the characterization of the associated technology as well as the social environment leading to the establishment of such technology.