치과주조용 Ti-Zr-Cr계 합금에서 Cr 함량변화가 부식저항성에 미치는 영향

박영준,강후원,이용렬,송호준,김민강 大韓齒科器材學會 2004 대한치과재료학회지 Vol.31 No.4

The purpose of this study was to develop new dental casting titanium (Ti) alloys having an excellent mechanical properties and good corrosion resistance as a substitute for c.p Ti and Ti-6Al-4V alloy (control groups). Ti-20Cr, Ti-2OZr and Ti-20Zr-XCr (X=2, 5, 10, 15) alloys (experimental groups) were designed for dental casting Ti alloys. Prior to casting prccedure, mother alloys were prepared by using vacuum arc melting with skull melting method. Argon-arc melting and argon/vacuum-pressure casting machine were used for making the specimens. The hardness, microstructure, and corrosion resistance were evaluated by using Vickers microhardness measurement, FE-SEM, and anodic polarization test. The results were as follows: 1. The Vickers microhardness (Hv) of Ti and Ti-6Al-4V alloy showed the values of 210 and 352, and Ti-20Cr and Ti-20Zr alloys showed the values of 341 and 259, respectively. As the Cr content increased from 0 to 15 % in Ti-20Zr-XCr (X=0, 2, 5, 10, 15) alloys, the Hv increased from 259 to 298, 457, 344, and 351, respectively. The microstructure of Ti-20Zr-XCr specimens showed significant difference by the concentration changes of Cr content showing acicular crystalline structure for Ti-20Zr-2Cr and Ti-20Zr-5Cr, and equiaxed crystalline structure for Ti-20Zr-10Cr and Ti-20Zr-15Cr. 2. Open-circuit potentials (E_(∝)) were rapidly decreased followed by steadiness as time elapse in all experimental groups except in Ti-20Z group. Ti-2OZr group showed an increase in E_(∝), from the first. 3. In potentiodynamic anodic polarization tests, all experimental groups showed more noble corrosion potential (E_(corr) than that of Ti-6Al-4V, and more basic E_(corr) than that of Ti. Especially, Ti-20Zr-10Cr alloy showed most favorable corrosion resistance among Ti-Zr-Cr alloys. 4. For Ti-20Zr-10Cr, Ti-20Zr-15Cr, and Ti-20Cr groups, which have more than 10% Cr content, the secondary corrosion potential shifted to noble direction in larger amounts than in the cases of control and other experimental groups. From these results, it was concluded that newly formulated Ti-20Zr-10Cr experimental alloy have adequate hardness and high corrosion resistance, and this alloy is promising candidate for a successful dental casting alloy.

양극산화와 열산화 처리로 형성된 티타늄 산화막의 표면 특성과 생체활성에 관한 연구

박영준,송호준,이용렬 大韓齒科器材學會 2004 대한치과재료학회지 Vol.31 No.4

The purpose of this study was to evaluate the surface characteristics of titanium oxide films formed by anodization and thermal oxidation techniques, and to investigate its effects on formation of calcium phosphate. As experimental specimen groups, naturally oxidized film (AS-R), thin anodic oxidation film (ANO-L), thick anodic oxidation film (ANO-H) treated up to dielectric breakdown voltage, and thermal oxidation films of TH-L and TH-H treated at 530℃ and 800℃ in the air, respectively, were prepared. Surface characterization was performed using field emission-scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) in order to evaluate the micro-morphology, crystalline structure, chemical composition, and binding structure of the oxide films. Bioactivity of specimen groups was investigated by evaluating the degree of calcium phosphate formation after immersing the samples in MEM for 7 days. The results were as follows: 1. Nanometer sized granular oxide particles were distributed on the surface of TH-L samples and sub-micrometer sized large crystallites were formed on TH-H samples. Irregularly shaped oxides were observed in ANO-L, and homogeneously porous oxide film having average pore size of about 0.5 ㎛ was formed in ANO-H. 2. Titanium oxide films having anatase crystalline structure were formed on ANO-L and TH-L sample surfaces. However, the preferred orientation crystal planes of ANO-L and TH-L were different to be (101) and (004) plane, respectively. Rutile crystalline structure was dominantly shown on TH-H sample, and anatase and rutile crystals were co-existed on ANO-H sample surfaces. 3. The amounts of hydroxyl group, which is related to the bioactivity of titanium implant, were higher in thermally treated specimen groups than in other groups. This result was analyzed to have close relation to the preferred orientation crystal plane and surface area of oxide films. The content of hydroxyl group increased as the density of surface titanium atoms increased, and that was least in specimen group having rutile and anatase crystalline structure in coexistence. 4. Immersion test in MEM showed that the capacity of calcium phosphate formation was dependent on total content of hydroxyl group and surface morphology of titanium oxides.

보디빌딩 선수들의 시합 전·후 신체조성과 체력 및 혈관탄성도 변화와 영양섭취 실태연구

곽재준,박재성,하수민,백영호 釜山大學校 附設 體育科學硏究所 2013 體育科學硏究所 論文集 Vol.30 No.-

The purpose of this study were to investigate a study of body composition, physical fitness, change of vascular compliance and nutrient intake status a before and after bodybuilders match. In this study, participants were 6 bodybuilders. The analyzed data brought about the following results by using paired t-test with SPSS 20.0. The results of the research were as follows. In to body weight and BMI were significantly increased but sit and reach were significantly decreased after match. There was non significantly difference in vascular compliance. Calories, lipids, carbohydrates, fiber and ash had significantly increased after match than before match. Calcium, iron, sodium, potassium, vitamin A, retinol, vitamin B1, vitamin B6, niacin, vitamin C, vitamin E had significantly increased after match than before match. Therefore, Bodybuilders need correct regular diet habit and exercise prescription after match. 본 연구는 B광역시 남자 보디빌딩 선수 6명을 대상으로 신체조성, 체력, 혈관탄성도 및 영양소 섭취상태를 시합 전·후를 분석하는데 목적이 있다. 자료처리는 SPSS 20.0 프로그램을 이용하여 paired t-test를 실시하였고, 연구결과에서 다음과 같은 결론을 얻었다. 시합전에 비해 시합후에 체중과 BMI는 유의하게 증가하였고, 유연성은 유의하게 감소하였고, 혈관탄성도는 유의한 변화가 없었다. 그리고 열량, 지질, 당질, 식이섬유 및 회분은 시합 전 보다 시합 후 유의하게 증가하였다. 또한, 칼슘, 철분, 나트륨, 칼륨, 비타민 A, 레티놀, 비타민 B1, 비타민 B6, 나이아신, 비타민 C, 비타민 E는 시합 전 보다 시합 후 유의하게 증가하였다. 이상을 종합하여 볼 때, 시합 전보다 시합 후에 영양소의 섭취증가로 인해 체중이 증가하는 것을 알 수 있으며, 이상의 연구 결과에서 시합전, 후의 식습관, 맞춤형 운동처방 및 체계적인 컨디셔닝 관리가 요구된다.

티타늄 상에 강유전성 barium titanate 박막 형성과 분극처리에 의한 유사체액 내에서의 calcium phosphate 생성 증진

박영준,이용렬,황규석,김은주,임용무,이기헌 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.2

This study was performed to fabricate a ferroelectric barium titanate (BaTiO₃, BTO) thin film on Ti substrate and to evaluate the effect of poling treatment for the improvement of calcium phosphate (Ca-P) formation. BTO thin-film was spin-coated on Ti substrate by dipping-pyrolysis technique using coating sol obtained by mixing Ba-naphthenate and Ti-naphthenate as starting substances. Pre-heating temperature of the BTO thin film was performed at 500℃ because organic-solvent was completely volatilized without any crystal growth, and the final heat treatment was performed at 600, 650, 700, 750, 800, 850℃, respectively. By repeating the coating and pre-heating procedure gor 20 times, homogeneous thin film of 0.7㎛ thickness could be fabricated, and it performed well during the poling treatment without breakdown. The final heating treatment of the BTO thin film at 750℃ produced a homogeneous crystalline structure without heterogeneous TiO₂formation, which was confirmed by field emission scanning electron microscope (FE-SEM) and X-ray diffraction analyser (XRD). An average grain size of 20∼30 ㎚ were confirmed by SEM observation. The final heat-treated BTO thin-films were polarized (Ep = 5 V/㎛) from 160℃ to 25℃ in heating chamber for 2 h. The negatively poled BTO thin film (N-BTO), non-poled BTO thin film (BTO), Ti substrate (Ti), and 600℃ heat-treated Ti (Ti-O) were immersed in SBF and Eagle's MEM solution for 15 days at 37℃. After the immersion period, the morphological and compositional changes of the surfaces were investigated using a FE-SEM and an energy dispersive X-ray spectrometer (EDX). After immersion in simulated body fluid (SBF), sodium chloride (Nacl) crystals were formed on Ti, Ti-O, and BTO surfaces due to anion adsorption (Cl), while Ca-P crystals were formed on N-BTO surfaces. We assumed that rapidly adsorded cations (Ca²□ ions) on the negatively charged surface at the initial stage acted as nuclei for the formation of Ca-P crystals. In MEM, sodium chloride (NaCl) was formed on Ti, and Ca-P layer including NaCl was formed on Ti-O. Weak and sparse Ca-P layers were formed on BTO, while thick, homogeneous, and dense Ca-P layer was formed on N-BTO, which was confirmed by FE-SEM and EDX. These results demonstrated that introducing a N-BTO on Ti is an effective method for the improvement of Ca-P formation in SBF and MEM. In conclusion, negatively charged ferroelectric BTO thin-film on Ti would improve the possibility of implant osseointegration.

치과용 갈륨합금의 조성변화가 부식 및 기계적특성에 미치는 영향

박영준,이용렬,이도재,Norling, Berry K,Rawls, H Ralph 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.2

This study was performed to evaluate the effects of compositional variations of dental gallium alloys on their corrosion and mechanical behaviors. 60Ag-28Sn-12Cu wt% (ST group) was prepare by atomization. ST-Pd and ST-Pt groups were prepared by substituting part of tin (Sn) with Pd (2 wt%) and Pt (0.05 wt%), respectively. Low-and high-copper amalgam alloys (LCA and HCA) were also prepared by atomization method for comparison. Alloy powders of each group were mixed with liquid gallium alloy that was composed of 61.98Ga-24.99In-12.98Sn-0.05Bi wt%. Specimens were made according to ADA specification no. 1. Corrosion behavior was evaluated by potentiodynamic anodic polarization test together with X-ray diffractometry (XRD), and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). 24 hour-compressive strengths and dimensional changes were measured. Following results were obtained. ST-Pd group showed most anodic behavior with the corrosion potential (E□) of-707 mV (vs. SCE), which is a significant shift in the noble direction from the -883 mV(vs.SCE) of the ST group (p<0.05). Among the specimens of St-Pd group, one specimen even had an E□ of -580 mV showing pronounced improvement in corrosion resistance. LCA group showed the worst corrosion resistance, having E□ of -896 mV. Set specimens had multi-phase microstructures consisting of Ag9In4, CuGa₂, □-Sn, Ag□₂Ga₂□, AG₄Sn and Cu3Sn, and all the groups showed similar XRD patterns. Ag9In4 was the main reaction matrix phase showing strongest XRD peak. CuGa2 phase surrounded the unreacted powder particles. A mixture of light Ag9In4 phase and a dark gray Ga42.3-Cu17.1-Ag16.8-Bi0.2 wt% solid solution appeared in the intergranular layer. ST-Pd group required the shortest mixing time. The intensity of the Ag4Sn peak of unreacted powder was lower and peak intensity of Ag□Ga₂□ phase, which is more corrosion resistant, was higher when compared to that of ST group. Sn(Cu)-Cl corrosion products having various morphologies were formed on corroded specimen surfaces. ST-Pd group had lesser deposition of corrosion product compared to other groups. LCA group specimens corroded more than HCA group specimens. 27-hour ST-Pd group showed highest value compared to those of other groups (p<0.05). HCA group showed higher compressive strength compared to that of LCA group. 24-hour setting expansions were ST-Pd*****(0.24%)<<LCH(0.43%)<ST-Pt(0.51%) <ST(0.56%)<<HCA(1.33). ST-Pd group showed significantly lower setting expansion (p<0.014). HCA group having 28 wt% Cu in alloy powder showed 1.33% setting expansion value which is significantly higher than those of other groups (p<0.01). In summary, substituting 2 wt% palladium for 2 wt% tin in the alloy powder improved the corrosion resistance and compressive strength, and reduced the degree of setting expansion. High-copper content induced excessive setting expansion. This finding indicates that there is still room for further improvement of the corrosion resistance and mechanical properties of dental gallium alloys through composition modification. With furher research, there is still a possibility for gallium alloy to become a successful substitute for dental amalgam.

변색 실활치에 대한 carbamide peroxide gel의 표백효과

박선아,김선호,황윤찬,오병주,윤창,박영준,정선와,황인남,오원만 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.4

The bleaching of discolored nonvital teeth is conservative treatement that satisfy the cosmetic desire. The most common method for this treatement, walking bleaching, is using 30% hydrogen peroxide and sodium perborate. Many alternatives are suggested for preventing the external cervical root resorption that is the common complication of the nonvital teeth bleaching with 30% hydrogen peroxide. The same extent of oxidation reactions as that resulted by the bleaching with the application of 30% hydrogen peroxide and sodium perborate can also be acquired more safely by materials that contain 10% carbamide peroxide, used primarily for the bleaching of vital teeth. Therefore, this study was performed to evaluate the efficacy of 10% and 15% carbamide peroxide bleaching gel in nonvatal teeth bleaching. The internal bleaching of intentionally discolored teeth was performed in vitro with 10% carbamide peroxide (Group 1), 15% carbamide peroxide (Group 2), mixture of distilled water and sodium perborate (Group 3), and mixture of 30% hydrogen peroxide and sodium perborate (Group 4). The bleaching materials were refreshed following 3, 6, 9 and 12 days. To evaluate the bleaching effect, the color change of the crowns was measured at 1, 2, 3, 4, 7 and 15 days of bleaching using the colorimeter. The results were as follows : 1. L^* and ΔE^* values were increased with time in all bleaching agents(p<0.01). 2. There was no significant difference in L^* and ΔE^* value among bleaching agents. 3. Δ^* value higher than 3 was shown after 3 days of bleaching with 10% carbamide peroxide gel, 1 day with 15% carbamide peroxide gel, 4 days with mixture sodium perborate and distilled water and 4 days with mixture sodium perborate and 30% hydrogen peroxide, respectively. These results revealed that the use of 10% and 15% carbamide peroxide bleaching gel in non-vital teeth bleaching is as effective as mixture of distilled water and sodium perborate and mixture of 30% hydrogen peroxide and sodium perborate. Accordingly, carbamide peroxide could be used clinically to bleach discolored non-vital teeth.

能動 Switched-Capacitor Filter에 관한 硏究

朴俊烈,具然健 弘益大學校 1981 弘大論叢 Vol.13 No.-

The Circuit of Switched capacitor integrator, which can be used as a basic block of filter design and has transfer functions independent of parasitic capacitances between any node and ground, is presented. The output characteristics when the duty cycle of trigger frequency is varied at 50%, and 25% are observed. The limitation of the sampling frequncy are defined. Ⅰ. 序 論 Ⅱ. 抵抗素子로서의 Switched-Capacitor Ⅲ. Miller積分器와 SC-積分器 Ⅳ. 實驗 및 考察 Ⅴ. 結 論 Ⅵ. 參考文獻 The Circuit of Switched capacitor integrator, which can be used as a basic block of filter design and has transfer functions independent of parasitic capacitances between any node and ground, is presented. The output characteristics when the duty cycle of trigger frequency is varied at 50%, and 25% are observed. The limitation of the sampling frequncy are defined.

1995學年度 新入生 實態調査

鄭水壽,朴州信,元俊載 仁荷大學校 學生生活硏究所 1996 學生生活硏究 Vol.16 No.-

痰飮에 應用되는 小調中湯이 高脂血症에 미치는 影響

文濬典,崔達永,朴元煥,尹相柱 대한동의병리학회 1993 동의생리병리학회지 Vol.8 No.-

연구배경 : 최근 우리나라에 있어서도 생활 양식의 서구화로 말미암아 다발하고 있는 각종 현대병의 하나인 고지혈증을 한의학적으로 치료하기 위한 방법론의 개발을 연구목적으로 하여, 한의학의 전통적 병인 개념인 담음이론을 통해 고지혈증의 한의학적 개념을 설명하고, 〈의학입문〉처방인 소조중탕을 통해 치료 약재의 개발 가능성을 실험적으로 규명하고자 한다. 방법 : 실험동물에 cholesterol현탁액을 투여하여 고지혈증을 유발시키면서, 〈의학입문〉에 수재된 소조중탕을 투여하여 혈청지질에 포함되어 있는 total-cholesterol, H. D. L-cholesterol, triglyceride, phospholipid 등의 함량변화를 관찰한다. 결과 : 血淸中 total-cholesterol과 triglyceride含量에 미치는 影響은 對照群에 比하여 매우 顯著한 有意性있는 減少가 나타났으며, 血淸中 H.D.L.-cholesterol과 phospholipid含量에 미치는 影響은 對照群에 比하여 有意性있는 減少가 나타났으며, 血淸中 total cholesterol과 HDL cholesterol의 比率은 對照群에 比하여 有意性이 認定되지 않지만 total cholesterol과 phospholipid의 比率은 對照群에 比하여 有意性이 認定된다. 결론 : 祛痰之劑인 小調中湯은 高脂血症의 改善에 有意性있는 成績을 나타내므로 高脂血症과 痰飮은 相關性이 있으며 脂質代謝異常에 따른 動脈硬化症에도 活用될 수 있는 것으로 思慮된다. In order to study the effects of Xiaotiaozhongtang on hyperlipidemia, white rats were induced by lipid metabolism disorder by the oral-injection of cholesterol. The effects of Xiaotiaozhongtang on lipid in serum were measured by the quantity of total-cholesterol and of H.D.L-cholesterol and of triglyceride and of phospholipid, by the rate of total-cholesterol vs H.D.L-cholesterol and of total-cholesterol vs phospholipid in serum. As a result, we can conclude as follows: 1. Effects of Xiaotiaozhongtang on total-cholesterol and triglyceride levels in serum of cholesterol treated rats were very noticeable. 2. Effects of Xiaotiaozhongtang on H. D. L-cholesterol and phospholipid levels in serum of cholesterol treated rats were noticeable. 3. Effect of Xiaotiaozhogtang on the rate of total-cholesterol vs H. D. L-cholesterol in serum of cholesterol treated rats was unnoticed, but on the rate of total-cholesterol vs phospholipid was noticeable. Thus,as the above-mentioned, on hyperlipidemia, the effects of Xiaotiaozhongtang can be recognized. Secondly, both hyperlipidemia and "phlegm-retention" have correlation each other. In the last place,Xiaotiaozhongtang may be used to artherosclerosis induced by, lipid metabolism disorder, hyperlipidemia.

최적 표준칫수 결정에 관한 연구

강준모,박영택 成均館大學校 科學技術硏究所 1989 論文集 Vol.40 No.2

This paper studies the problem of determining the optimal standard product sizes minimizing the loss function, which is composed of demand distribution and preference functions. The customer who wants to buy the product of size x in the range x_(i-x)<x<x_i may purchase the product of size u_i. Size u_i represents the standard product size which covers the interval (x_(i-1), x_i). Purchasing desire decreases as the difference between a customer's requirement(x) and the standard product size(u_i) increases. The standard product sizes u_i and the range limits x_i can be determined so as to minimize the loss function.