Characterization and Property Evaluation of Ti‑Based Target Materials and Their Nitride Nano‑composites Coating Layers

Jeong‑Han Lee,Hyun‑Kuk Park,장준호,Ik‑Hyun Oh 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.1

This study formed a hard TiAlSiWN coating layer using Ti, Al, Si and W raw powders that were mechanically alloyed andrefined. The TiAlSi and TiAlSiW coating targets were fabricated using a pulse current activated sintering process in a shorttime with the optimal sintering conditions. The optimized sintering condition was obtained by controlling process parameterssuch as temperature, pressure, heating rate and pulse ratio (on/off). The coating targets were successfully deposited onthe WC substrate to form the TiAlSiN and TiAlSiWN nitride nano-composite structures by an arc ion plating process andalso, their coating layers were compared according to the addition of W element. The microstructures of the nitride nanocompositecoating layer were analyzed, focusing on the distribution of the crystalline phases, amorphous phases (Si3N4),and growth orientation of the columnar crystal depending on the addition of W element. The mechanical properties of thecoating layers were exhibited a hardness of approximately 3000 kg/mm2 and adhesion of about 117.77 N in the TiAlSiN. Inparticular, the TiAlSiWN showed excellent properties with a hardness of more than 4300 kg/mm2 and an adhesion of about181.47 N, respectively.

비만증 환자에서 한약제에 의한 체중 감소효과

Oh, Seung-Joon,Jeong, In-Kyung,Kim, Young-Seol,Choi, Young-Kil,Paeng, Jeong-Ryung,Bae, Jung-Hwan,Shin, Hyun-Dae 경희대학교 동서의학연구소 1999 INTERNATIONAL SYMPOSIUM ON EAST-WEST MEDICINE Vol.1999 No.1

Seung-Joon Oh, In-Kyung Jeong, Young-Seol Kim, Young-Kil Choi, Jeong-Ryung Paeng¹, Jung-Hwan Bae and Hyun-Dae Shin²Department of internal Medicine, College Medicine, Endocrine Research Institute¹. Department of Rehabilitation, College of Oriental Medicine², Seoul, korea. Bady Fat Reduction Effects of Red Ginseng Compound Preparation on the Patients with Obesity. Proceedings of International Symposium on East-West Medicine, Seoul. 244-254, 1999.-Obesity can be defined as a metabolic disease due to an increased state of fat tissues caused by an imbalance of calorie intake and use. Recently, in Korea by improvement and westernization of food intake, along with decrease in exercise activities, the prevalence of obesity has increased greatly. Our objectives were to study stability and effects of decrease in body fat by administering red ginseng compound preparation (known to have body fat decreasing effects in laboratory animals) to obesity patients on low calorie diets. Changes in weight and body fat were measured while carrying out calorie-restricted diets on patients for 4 weeks, then administering red ginseng compound preparation for another 4 weeks. The patients were 20 people whose BMI were 25kg/㎡ or over and whose percent body fat was also 30% or over when tested by bioelectrical conductivity. 1. Changes in weight were from 70.04kg(base line) to 67.43kg(after taking red ginseng compound preparation). 2. In similar sense, BMI decreased from 27.12kg/㎡(base line) to 26.56kg/㎡(after dieting), and further to 26.01kg/㎡ (after taking red ginseng compound preparation). The BMI seemed to decrease significantly compared to the baseline after the use of red ginseng compound. 3. Waist hip ratio was changed from 0.8858(base line) to 0.8728, but it was statistically insignificant. 4. The percent body fat was 35,16%(base line), 33.87%(after dieting), and 31.68%(after taking red ginseng compound preparation). 5. Complete blood cell count and blood chemisrty remained unaffected by the administration. 6. In concern to endocrinologic studies, T3 decreased from 118.7 to 98.2ng/dL, and T4 increased from 8.8 to 9.2㎕/ dL. Epinephrine showed a tendency to decreased from 0.27 to 0.25 ng/mL, and norepinephrine increased from 0.39 to 0.44ng/mL. 7. Leptin was not changed. 8. Some patients complained adverse effects; constipation(5 patients, may be due to diet therapy), fatigue (2 patients), pruritus(2 patients), flushing(s patients), dizziness(3 patients) and epigastric discomfort(2 patients). However their symptoms were mild, so medication did not stopped. In conclusion, loss of weight without significant side effects was observed during low calorie diet and red ginseng compound preparation administration. This is thought to be in relation to sympathetic nerve system rather than adrenal gland. Also, further long0term studies should be required, since the observed results were based on short-term changes in weight.

Effect of Mechanical Alloying on the Microstructural Evolution of Al60Cr30Si10 Alloys Processed by Spark Plasma Sintering

Jeong‑Han Lee,Ik‑Hyun Oh,Jun‑Ho Jang,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.5

In this study, Al, Cr and Si fine powders were alloyed by planetary ball milling to investigate their microstructural evolution,following their mechanical alloying behavior. The formation of Al(Cr) supersaturated solid solution by the Cr grainsembedded in Al-matrix, which contributed substitutional structure is discussed in relation to their structural evolution inaccordance with the distortion of a crystal lattice. The compacts of Al–Cr–Si alloys were prepared by rapid sintering withina short time by dense consolidation above the density of 99.9% as the formation of intermetallics, except in the case of thedistribution of single-phases induced by the Al-melting. The formation behavior of intermetallics was dominated by dependenceon the structures of the milled-powder and subsequent sintering temperature. To estimate the consolidated behaviorsof compacts, various approaches derived from TEM and XRD analysis were taken to obtain microstructural evidences ofthe inter-diffusion, following the presence of thermally stable intermetallics.

Rapid Consolidation of WC‑ZrSiO4 Hard Materials by Spark Plasma Sintering: Microstructure, Densification, and Mechanical Properties

Jeong‑Han Lee,Ik‑Hyun Oh,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9

Densely consolidated WC-based hard materials with 5–20 vol% ZrSiO4was fabricated by spark plasma sintering at 1400 ℃ ata constant heating rate of 70 ℃/min−1. To achieve mechanical alloying of WC-ZrSiO4, planetary ball milling was carried outfor 12 h, during which the brittle-brittle components (WC-ZrSiO4) became fragmented and their particles became refined. Itwas observed that certain, specific, non-isothermal sintering kinetics, such as apparent activation energy, sintering exponents,and densification strain, affected the densification behavior. The evolution of phase structure from powder to compact wasfound to be related the lattice distortion and micro-strain in the basal planes of WC. By examining the mechanical propertiesof the samples, it was that the added zircon content leads to enhanced fracture toughness (12.9 MPa m1/2) owing to thepresence of WC-ZrSiO4 in the cemented carbide. In fact, the microcrack propagation of the fracture passed through zirconfrom a transgranular to a ductile component (fcc) where the crack tips could be absorbed.

Influence of Phase Composition in TiAlSiN Hard Coatings on the Evolution of Structure and Mechanical Properties

Jeong‑Han Lee,Ik‑Hyun Oh,Jun‑Ho Jang,Ju‑Hun Kim,Sung‑Kil Hong,Hyun‑Kuk Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.3

The aim of this study is to investigate the structural evolution and mechanical properties of TiAlSiN coatings when processedby the arc ion plating method. To form a hard coating, Ti, Al, and Si powders were mechanically alloyed by planetary ballmilling; the powders were then densely compacted during a rapid sintering process into a ternary system coating, i.e. TiAlSi. The evolution of the structural phase from a powder to a compact material is dominated considerably by phase states suchas a supersaturated solid solution or intermetallic compounds. In the case of coating layers, the factors that determine thestructural evolution are associated with the phase stability of the nano-crystalline structure that in turn is associated withthe Ti/Al composition ratio. Motivated by this, we performed experiments to investigate the distribution of microstructures;the material’s binding energy, quantitative properties, transformation of crystal structure, and distribution of amorphous/crystalline were all recorded. In particular, the relationship between the physical and chemical properties during the coatingprocess is considered to be the dominant factor controlling the orientation and morphology of that zone (1, T, and 2). TheTiAlSiN coating layer was found to have hardness above 45 GPa and an adhesion above 100 N. In other words, understandingthe evolution and structure of TiAlSin helped us to produce a material with excellent properties that can be used as a hardcoating. Specifically, these properties were induced by a grain refinement of the nano-crystalline structure that correspondsto an increase in the silicon nitride contents.

수단-목적 사슬 이론을 이용한 의복품질 평가과정에 관한 이론적 연구 : A Theoretical Study

오현정,이은영 한국의류학회 1998 한국의류학회지 Vol.22 No.4

The purpose of this study was to discover a conceptual framework and evaluation process of apparel quality by means-end chain theory. The theoretical study was conducted to find out a conceptual framework and build a hypothetical evaluation process model of apparel quality. Apparel quality was perceived associative network called a means-end chain and was evaluated in several stages. A conceptual framework of apparel quality evaluation was organized into hierarchical relationships among four different dimensions: physical attribute, physical function, instrumental performance, and expressive performance. The means-end structure linked tangible physical attributes and function to more abstract instrumental and expressive performance. A hypothetical evaluation process model linked dimensions of apparel quality to the selected means-end relationship. Different consumers had different means-end chains for the same apparel. Therefore different subjects are likely to have different evaluation paths. From this study we can suggest an evaluation process model of apparel quality.

의복색 선호를 중심으로 한 남자 대학생의 패션 관심도 및 성역할 태도에 관한 연구

오경화,정삼호,이현정 중앙대학교 생활과학연구소 2000 생활과학논집 Vol.13 No.-

The purpose of this study is to investigate the preference for clothing color, fashion interest, and sex-role attitude in the group of male university student. The survey used questionnaires that distributed to randomly sampled 439 male university students(18~27 years of age) in Seoul. For the analysis of the data, frequency distribution, ANOVA, χ^2-square, F-test, Duncan's multiple test have been conducted and the Cronbach's α has been calculated to measure the reliability. The results of this study are as follows : 1. Male university students much more favored cool color than warm color, and liked monochromatic, analogous than complementary. 2. The preference for clothing color were appeared to be influenced by the age and the major. 3. The group of androgynous and male university students in art major showed the highest fashion interest. Fashion interest of male university students tend to decreased as the grade which they are in increased. 4. The preference for clothing color are closely related to the fashion interest and sex-role attitude.

치과용 디지털 색상 분석용 기기의 정확성과 재현 능력에 대한 평가

정중재,박수정,조현구,황윤찬,오원만,황인남 大韓齒科保存學會 2008 Restorative Dentistry & Endodontics Vol.33 No.4

본 연구에서는 치과용 디지털 색상 분석기기 중 하나인 ShadeScan (CYNOVAD, Montreal, Canada)의 색상 분석의 정확성과 재현 능력을 평가하였다. 균일한 치아 배열을 가진 20대 성인 남자 8명과 여자 8명의 상악 인상을 고무인 상제 (Exaflex, GC, Japan)를 이용하여 채득하고, 인상에 A2 색상의 임시 크라운 제작용 자가중합형 레진을 주입하여 치아 모델을 완성하고, ShadeScan을 이용해 각 치아의 영상을 얻어 컴퓨터의 ShadeScan 프로그램으로 분석하였다. 그리고 측정 결과의 재현 능력를 평가하기 위해 2개의 치아 모델을 임의로 선택하여 각 치아마다 10회의 색상 측정을 시행하여 분석 결과를 비교하였다. 또한 분석된 영상의 동일 shade 간의 색차를 확인하기 위해 광중합 복합레진인 Gradia Direct (GC, Tokyo, Japan)와 shade guide의 CIE L^(*)a^(*)b^(*) 값을 백색과 흑색 배경판 상에서 spectrophotometer (Spectrolino, GretagMacbeth, USA)로 측정하고, ShadeScan에 의해 동일한 shade로 분석된 shade guide간의 색차를 계산하여 다음의 결과를 얻었다. 모든 치아에서 모델 제작 재료와 동일한 A2 색상므로 분석된 경우는 없었으며, 개개의 치아에서 전체 순면이 동일한 색상으로 분석된 예는 없었다. 또한 동일한 치아군에서 치아의 크기 , 형태 , 순면의 굴곡 등에 따라 서로 다른 색상 분포를 보였다. 재현성 평가에서 각 치아의 중앙부는 비교적 일정한 재현성출 보였으나, 절단부와 주변 부위는 재현성이 낮았으며, 동일한 shade로 분석된 shade guide 간에는 3 이상의 색차 (ΔE^(*))를 보였다. 이상의 결과는 치과용 디지털 색상 분석기기는 비록 높은 재현 능력은 가지고 있지만 정확성에 오류가 있음을 시사하며 , 따라서 이러한 기기를 이용한 색상 분석 시 좀 더 세밀한 주의와 다른 방법의 추가 사용이 필요하리라 사료된다. This study was done to evaluate the reliability of the digital color analysis system (ShadeScan, CYNOVAD, Montreal, Canada) for dentistry. Sixteen tooth models were made by injecting the A2 shade chemical cured resin for temporary crown into the impression acquired from 16 adults. Surfaces of the model teeth were polished with resin polishing cloth. The window of the ShadeScan handpiece was placed on the labial surface of tooth and tooth images were captured, and each tooth shade was analyzed with the ShadeScan software. Captured images were selected in groups, and compared one another. Two models were selected to evaluate repeatability of ShadeScan, and shade analysis was performed 10 times for each tooth. And, to ascertain the color difference of same shade code analyzed by ShadeScan, CIE L^(*)a^(*)b^(*)values of shade guide of Gradia Direct (GC, Tokyo, Japan) were measured on the white and black background using the Spectrolino (GretagMacbeth, USA), and Shade map of each shade guide was captured using the ShadeScan. There were no teeth that were analyzed as A2 shade and unique shade. And shade mapping analyses of the same tooth revealed similar shade and distribution except incisal third. Color difference (ΔE^(*)) among the Shade map which analyzed as same shade by ShadeScan were above 3. Within the limits of this study, digital color analysis instrument for dentistry has relatively high repeatability, but has controversial in accuracy.

인터리버를 이용한 eHDR-WPAN 시스템의 성능 분석

정승희,이현재,오창헌 한국기술교육대학교 2006 論文集 Vol.12 No.1

In this paper, we propose a performance of improvement method for eHDR-WPAN system with Interleaver. The pattern of burst error caused by fading in indoor wireless channel. For the reason, using of Interleaver(make burst error to random error) can be enhanced to error-rate in eHDR-WPAN system. Interleaver at the simulation considered Convolutional, Block and Random, respectively. Available symbol spacing of Interleaver is assumed 9 and 27. In results, Block-Interleaver is shown that a performance of improvement about 0.6dB of E_(b)/N_(o) at 10^(-4). Therefore, the suitable Interleaver for eHDR-WPAN system was 9 symbol spacing of Block Interleaver.

성격유형과 의복품질 평가

오현정 한국심리유형학회 2001 심리유형과 인간발달 Vol.8 No.-

본 연구의 목적은 성격유형과 소비자의 의복품질 평가를 분석하여, 의복품질 평가 요인을 변별할 수 있는 소비자의 성격유형을 발견하고, 이로써 의복 구매시 소비자들의 평가행동을 예측하고자 하였다. 측정도구는 MBTI 검사와 의복 구입 시 기대사항에 대한 질문지를 사용하였고, 조사 대상은 성인여성으로 편의 표집되었으며, 최종 분석에 사용된 자료는 총 275부이었다. 자료분석은 윈도우용 SPSS 10.0 프로그램을 이용하였으며, 빈도분석, 요인분석, t-test, one-way ANOVA를 사용하였다. 선호지표와 심리유형, 기질유형, 융의 기능유형별로 의복품질 평가의 사이를 분석한 결과 상대적으로 유의한 차이를 많이 보인 성격유형은 선호지표와 심리유형이었다. 의복 구매나 선택시 소비자 행동을 예측하기 위한 성격 특성은 선호지표와 심리유형임을 알 수 있었다. 선호지표별 유의한 차이를 보인 의복품질 평가요인은 '편안함', '관리성', '물리적 속성', '물리적 기능성', '심미성'이었다. 심리유형별 유의 차를 보인 의복품질 평가요인은 '경제성', '물리적 기능성', '물리적 속성', 그리고 '심미성' 이었다. The purpose of this study was to determine if personality types affect apparel quality evaluation. Personality types was applied using Myers-Briggs Type Indicator(MBTI). The data were collected from 275 female using questionnaire to evaluate on apparel quality, and were analysed with frequency, factor analysis, t-test, one-way ANOVA. Results revealed several significant differences with apparel quality evaluation to personality type. Introvert types were significantly evaluated 'comfort' more than extrovert types. Sensing types were significantly evaluated 'easy care' more than intuition types. Thinking types were significantly evaluated 'physical attributes' more than feeling types. Judging types were significantly evaluated 'physical attributes', 'physical function', and 'aesthetics' more than perceiving types. STs were significantly evaluated 'physical attributes', 'physical function', and 'aesthetics' more than others. NTs were significantly evaluated 'economy', 'physical function', and 'aesthetics' less than others. NFs were significantly evaluated 'economy' more than others and evaluated 'physical attributes' less than others. SFs were significantly evaluated 'physical function' less than others.