• Corrosion Science and Technology
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• 제23권1호
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• pp.41-53
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• 2024

Titanium alloy is gaining attention in the medical industry due to its excellent biocompatibility and osteoconductivity. However, the natural oxide film on the titanium surface is insoluble, resulting in inadequate bone adhesion. Therefore, it is necessary to optimize the contact between biological tissues and implant surfaces, and alter the chemical composition and morphological characteristics of the implant surface. In this study, the anodization method was applied to titanium surface treatment to form a uniform and robust oxide film. Subsequently, a chemical process, pore-widening, was employed to change the morphological characteristics of the oxide film. The concentration of the pore-widening solution was varied at 2, 4, 6, and 8 wt% and the process time was set at 30 and 60 minutes. As the concentration of the pore-widening solution increased the pore diameter of the oxide film increased. Notably, at 6 wt% for 60 minutes, the oxide film exhibited a coexistence of pillars and pores. Based on this, it was determined that surface roughness increased with higher concentration and longer process time. Additionally, the presence of pillars and pores structures maximized hydrophilicity. This study provides insights into enhancing the surface properties of titanium for improved performance in medical implants.

• 한국구조물진단유지관리공학회 논문집
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• 제12권4호
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• pp.187-194
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• 2008

도로교량의 경우 급속한 도시화로 인해 증가한 교통량을 처리하기 위해 교량확폭과 신설교량의 추가 건설 등의 방법이 사용되고 있다. 하지만 현재 국내에서는 확폭 또는 신설 교량의 추가건설의 타당성을 판단하기 위한 합리적인 절차나 기준이 마련되어 있지 않다. 또한 교량 확폭 공사 시에는 일반적인 교량신설 공사에 비해 불확실성을 내포한 사건들이 추가적으로 존재한다. 이에 본 논문에서는 의사결정수 방법을 이용해 교량확장에 따라 발생 가능한 사건의 기대 위험비용을 체계적으로 고려할 수 있는 개선된 형태의 생애주기비용 분석 모델을 제안하였다.

• 한국재료학회지
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• 제13권9호
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• pp.593-597
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• 2003

Anodic aluminum oxide (AAO) membrane was made of aluminum sheet (99.6%, 0.2 mm thickness). The regular array of hexagonal nano pores or channels were prepared by two step anodization process. A detail description of the AAO fabrication is presented. After the 1st anodization in oxalic acid (0.3 M) at 45 V, The formed AAO was removed by etching in a solution of 6 wt% $H_3$$PO_4$＋1.8 wt% $H_2$$CrO_4$. The regular arrangement of the pores was obtained by the 2nd anodization, which was carried out in the same condition as the 1st anodization. Subsequently, the alumina barrier layer at the bottom of the channel layer was removed in phosphoric acid (1M) after removing of aluminum. Pore diameter, density, and thickness could be controlled by the anodization process parameters such as applied voltage, anodizing time, pore widening time, etc. The pore diameter is proportional to the applied voltage and pore widening time. The pore density and thickness can be controlled by anodization temperature and voltage.

• 한국지역지리학회지
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• 제17권4호
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• pp.416-431
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• 2011

지리산과 한라산을 대상으로 산악 국립공원 등산로의 훼손 유형을 요인별로 조사하였다. 등산로 훼손은 침식프로세스가 진행되는 장소에 따라 노면 저하, 측벽 후퇴, 노면 확대 및 분기로 구분할 수 있다. 노면 저하와 측벽 후퇴가 주로 자연적인 침식 요인에 의해 일어나는 훼손 유형인 반면 노면 확대 및 분기는 인위적인 답압으로 발생하는 훼손 유형이다. 노면 저하를 일으키는 가장 탁월한 프로세스는 우세이며, 측벽 후퇴는 등산로의 물리적 환경에 따라 우세, 서릿발작용, 취식, 도목, 동물작용 등 탁월한 프로세스가 달라진다. 노면 확대 및 분기는 탑압을 일으키는 원인에 의해 유형화할 수 있다. 지표류에 의해 등산로 노면이 낮아지는 과정에서 드러난 나무뿌리, 자갈 및 암반과 국지적인 세굴로 인하여 노변에 만들어진 높낮이차 등 우세와 관련하여 발생하는 훼손 사례가 많다. 또한 평탄면 등산로에서는 물웅덩이, 산림지대의 등산로에서는 천근성 수목인 구상나무의 도목이 노면 확대 빛 분기의 주요 원인이 된다. 돌깔기 공법처럼 노변 보호공법이 오히려 등산객의 등산로 이탈을 조장하기도 하며, 보행에 불편을 주는 요소가 없더라도 등산객이 지름길을 만드는 과정에서 노면 확대 및 분기가 발생할 수 있다.

• Clinics in Shoulder and Elbow
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• 제13권2호
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• pp.280-285
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• 2010

목적: 견봉, 오구견봉 인대 및 오구돌기의 끝을 포함하는 오구견봉 간격과 회전근개 사이에서 발생하는 충돌 징후로 인해 발생하는 오구 충돌 증후군은 양궁에서 흔히 볼 수 있는 자세인, 팔을 전방 거상, 내회전 및 내전시에 상완골 소전자가 오구돌기에 접촉하면서 통증이 유발될 수 있다. 대상 및 방법: 보존적 치료로 조절되지 않는 오구 충돌 증후군을 호소한 20세 여자 양궁선수에 대하여 관절경하 오구돌기 성형술 시행 후 발생한 통증을 동반한 회전근 간격 증가에 대하여 관절경하 중첩술을 시행하였다. 결과: 관절경하 회전근 간격 중첩술 시행 후 6개월 추시상, 통증 및 기능 호전을 보이고 성공적으로 양궁 선수로 복귀하였다. 결론: 저자들은 보존적 치료로 조절되지 않는 오구 충돌 증후군을 호소한 20세 여자 양궁선수에 대하여 관절경하 오구돌기 성형술 시행 후 발생한 통증을 동반한 회전근 간격 증가에 대하여 관절경하 중첩술을 시행하여 통증 및 기능 호전을 보이고 성공적으로 양궁 선수로 복귀한 증례를 경험하였기에 보고하고자 한다.

• 한국재료학회지
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• 제12권2호
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• pp.121-128
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• 2002

Anodic alumina layer can be used as templates for preparation of nano-structured materials, because porous oxide layer on aluminum shows a uniform pore size and a high pore density. In order to find out possibility for template material to prepare nano wire, the effects of the anodic applied potential, anodic time and the temperature of electrolyte on pore diameter of anodic alumina layer were studied using SEM and AFM. The pore diameter of anodic alumina layer increased with applied anodic potential and electrolytic temperature. Especially, the pore diameter of anodic oxide layers formed in chromic acid can be well replicated by widening process in $H_3$$PO_4$solution.

• 한국재료학회지
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• 제12권1호
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• pp.89-93
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• 2002

To investigate the effect of properties of pores in anodic alumina template(AAT) on the formation and characteristics of metal nano wires, Cu and Ni nano wires were manufactured using anodic alumina template formed in various electrolytes. The characteristics of prepared metal nano wires using AAT could be replicated from those of pores in AAT. The diameters of nano wires could be controlled by the widening process of anodic porous film in $H_3PO_4$ solution. The shape ratio of the nano wire was shown to be $170{\pm}30$ for Ni nano wire formed by AAT made in sulfuric acid.

• 한국전기전자재료학회논문지
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• 제21권5호
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• pp.415-420
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• 2008

AAO films were fabricated on two kinds of substrates such as $Al/SiO_2/Si$ and Al/Ni/Ti/Si. To obtain well-aligned AAO film, we optimized process condition for buffer layer, electrolyte and voltage. In the case of oxalic acid, the AAO film with pore size of approximately 45 nm was obtained at voltage of 40 V, temperature of $10^{\circ}C$, oxalic acid of 0.3 M and widening time of 60 min. Then the thickness of barrier is less than 600 nm. In the case of sulfuric acid, the AAO film has pore size of 40 nm and barrier thickness of 400 nm with optimum conditions such as voltage of 25 V, temperature of $8^{\circ}C$, sulfuric acid of 0.3 M and widening time of 60 min.

• 한국전기전자재료학회논문지
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• 제18권8호
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• pp.708-713
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• 2005

An alumina membrane with nano-sized pore array by anodic oxidation using the thin film aluminum deposited on silicon wafer was fabricated. It Is important that the sample prepared by metal deposition method has a flat aluminum surface and a good adhesion between the silicon wafer and the thin film aluminum. The oxidation time was controlled by observation of current variation. While the oxalic acid with 0.2 M was used for low voltage anodization under 100 V, the chromic acid with 0.1 M was used for high voltage anodization over 100 V. The nano-sized pores with diameter of $60\~120$ nm was obtained by low voltage anodization of $40\~80$ V and those of $200\~300$ nm was obtained by high voltage anodization of $140\~200$ V. The pore widening process was employed for obtaining the one-channel with flat surface because the pores of the alumina membrane prepared by the fixed voltage method shows the structure of two-channel with rough surface. Finally, the sample was immersed to the phosphoric acid with 0.1 M concentration to etching the barrier layer.

• Journal of Electrical Engineering and Technology
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• 제10권6호
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• pp.2364-2367
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• 2015

In this study, we fabricated an electrolyte-insulator-metal (EIM) device incorporating a high-k Al₂O₃ sensing membrane using a porous anodic aluminum oxide (AAO) through a two-step anodizing process for pH detection. The structural properties were observed by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction patterns (XRD). Electrochemical measurements taken consisted of capacitance-voltage (C-V), hysteresis voltage and drift rates. The average pore diameter and depth of the AAO membrane with a pore-widening time of 20 min were 123nm and 273.5nm, respectively. At a pore-widening time of 20 min, the EIM device using anodic aluminum oxide exhibited a high sensitivity (56mV/pH), hysteresis voltage (6.2mV) and drift rate (0.25mV/pH).