세리아 안정화 지르코니아의 제조 및 특성(I) : CeO₂첨가량 변화에 따른 Ce-TZP의 기계적 특성

정승화,강종봉,Jung, Seung-Hwa,Kang, Jong-Bong 한국재료학회 2010 한국재료학회지 Vol.20 No.7

The usual ceramic process of mixing and milling in state of oxides $ZrO_2$ and $CeO_2$ was adopted in this study in a wet process to manufacture Ce-TZP. $CeO_2$-$ZrO_2$ ceramics containing 8~20 mol% $CeO_2$ were made by heat treatment at $1250\sim1500^{\circ}C$ for 5hr. The maximum dispersion point of every slurry manufactured with a mixture of $ZrO_2$ and $CeO_2$ was neat at pH10. A stable slurry with average particle size of 90 nm can be manufactured when it is dispersed with the use of ammonia water and polycarboxylic acid ammonium. The sintered Ce-TZP ceramics manufactured with the addition of $CeO_2$ in a concentration of less than 10 mol% progressed to the fracture of the specimen due to the existence of a monoclinic phase of more than 30% at room temperature. More than 99% of the tetragonal phase was created for the sintered body with the addition of $CeO_2$ beyond 18 mol%, but the degradation of the mechanical properties on the entire specimen was brought about due to the $CeO_2$ existing in a percentage above 3%. Consequently, the optimal Ce-TZP level combined in the oxide state was identified to be 16 mol% of $CeO_2$ contents.

유입구 개방형 초저낙차 횡류수차의 성능

정승화(Seung-Hwa Jung),황영철(Yeong-Cheol Hwang),최영도(Young-Do Choi) 한국유체기계학회 2014 한국유체기계학회 학술대회 논문집 Vol.2014 No.11

사물인터넷망에서의 오픈 문제에 대한 보안 문제 분석

정승화(Sung Hwa Jung),김정태(Jung Tae Kim) 한국정보과학회 2016 한국정보과학회 학술발표논문집 Vol.2016 No.6

개수로용 횡류수차의 흡출관 적용에 따른 성능연구

정승화(Seung-Hwa Jung),최영도(Young-Do Choi) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.춘계 No.-

앉은 자세에서 방석센서를 이용한 요통환자 골반가동성 측정의 신뢰도와 타당도

정승화 ( Seung-hwa Jung ),박대성 ( Dae-sung Park ) 대한물리의학회 2020 대한물리의학회지 Vol.15 No.2

PURPOSE: Postural and structural asymmetry due to muscle imbalances around the lower back and pelvis are the causes of back pain. Muscle imbalances in patients with chronic low back pain affect the pelvic tilt and movement, and it is necessary to assess the pelvic movement ability using the appropriate tools to determine the mediating effects of lower back pain. This paper reports the reliability and validity of the Sensbalance Therapy Cushion (STC) for pelvic movement and proprioception. METHODS: In this study, the Wii balance board (WBB) was used as a golden standard for pelvic movement measurements. FABQ, KODI, Myovision, and Pelvic movement were measured in 50 patients with chronic low back pain. The correlation between the lower-back muscle activity and pelvic movement was checked. The pelvic movement parameter was measured twice to determine the intra-rater reliability. RESULTS: The STC showed high test-retest reliability in the pelvic tilt measurements (ICC = .672 - .809). The testretest reliability of proprioception measurements (ICC = .588 - .859) and reaction time measurements (ICC = .542 - .836) were also high. The relationship between the WBB and STC showed a significant positive correlation with the pelvic tilt test (p < .01). The posterior pelvic tilt and lower-back muscle activity showed a significant negative correlation (p < .01). The pelvic left tilt and lower-back muscle activity showed a significant negative correlation (p < .05). CONCLUSION: The results revealed the high reliability and validity of the STC. Therefore, the STC can be used as an objective measuring device for evaluating pelvic tilt, proprioception, and reaction time in low back pain patients.

MCT를 이용한 공인중개사의 도덕적 판단력에 관한 연구

정승화(Seung-Hwa Jung),신은정(Eun-Jung Shin) 건국대학교 부동산도시연구원 2018 부동산 도시연구 Vol.10 No.2

공인중개사의 윤리적 판단은 전문자격사와 전문직업인, 사회구성원으로서 중요한 요소임에도 불구하고 이를 평 가하는 척도는 매우 부족한 실정이며 제고방안에 대한 연구도 미흡한 실정이다. 따라서 본 연구는 이러한 필요성에 입각하여 공인중개사의 도덕적 판단력과 영향요인들에 대하여 고찰하고 이를 기초로 공인중개사의 윤리의식 제고방 안에 효과적인 방향을 제시하는데 도움이 되는 자료를 제공하는 것을 목적으로 한다. 이를 위하여 도덕성 측정 도구 중의 하나인 도덕 판단력 검사(Moral Competence Test)를 활용하여 2017년 8월 서울특별시의 개업공인중개사를 대 상으로 설문조사하여 분석하였다. 도덕적 판단력을 종속변수로 다중회귀분석한 결과, 연령이 높을수록 도덕적 판단 력이 낮아지는 것으로 분석되었고, 실제소득보다 낮은 수준으로 신고하여 간이과세자가 되는 간이과세자일수록 도 덕적 판단력이 낮아지는 것으로 분석되었다. 본 연구는 공인중개사의 윤리의식에 대하여 도덕적 판단력이라는 형태 로 계량화하였다는 점에서 그 간의 연구와 차별성이 있다. The moral judgments of real estate agents are important factors for professionals and social members carrying out real estate transactions. However, until now, neither the evaluation of the moral consciousness nor the research for its improvement have been sufficient. Therefore, this study examines the moral judgment and factors influencing that of real estate agent. The purpose of this paper is to provide an effective direction for raising moral awareness of real estate agents. This study was conducted by surveying real estate agents in Seoul in August 2017 using the Moral Competence Test(MCT), one of the measuring tools of morality. After multiple regression analysis of moral judgment into dependent variables, a negative correlation was found between moral judgment and the age of certified realtors. In addition, lower moral judgment was found in the low income group of respondents, and the moral judgment of simplified taxpayers was lower than that of the general taxpayer groups. However, this study has limitations as it fails to reflect many other factors that affect moral judgment.

나일론 시트와 염료를 이용한 고감도 색변환 포름알데히드 가스 센서

정승화 ( Suenghwa Jung ),조영범 ( Yeong Beom Cho ),김용신 ( Yong Shin Kim ) 한국센서학회 2017 센서학회지 Vol.26 No.6

A colorimetric sensor was investigated to achieve a low-cost warning device for harmful gaseous formaldehyde (HCHO). The sensor is based on selective reactions between hydroxylamine sulfate and HCHO, leading to the production of sulfuric acid. The produced acid results in color-changing response through the acid-base reaction with dye molecules impregnated on a solid membrane substrate. For attaining this purpose, sensors were fabricated by drop-casting a dye solution prepared using different pH indicators on various commercially available polymer sheets, and their colorimetric responses were evaluated in terms of sensitivity and reliability. The colorimetric sensor using bromophenol blue (BPB) and nylon sheet was found to exhibit the best performance in HCHO detection. An initial bluish green of a sensor was changed to yellow when exposed to gaseous formaldehyde. The color change was recorded using an office scanner and further analyzed in term of RGB distance for quantifying sensor’s response at different HCHO(g) concentrations. It exhibited a recognizable colorimetric response even at 50 ppb, being lower than WHO’s standard of 80 ppb. In addition, the sensor was found to have quite good selectivity in HCHO detection under the presence of common volatile organic compounds such as ethanol, toluene, and hexane.

소수력용 횡류수차의 성능 및 활용에 관한 연구

정승화(Seung-Hwa Jung),최영도(Young-Do Choi) 한국유체기계학회 2015 한국유체기계학회 학술대회 논문집 Vol.2015 No.6

요통환자에 대한 새로운 표면 근전도 방법의 신뢰도와 타당도

정승화(Jung, Seung-Hwa),박대성(Park, Dae-Sung) 한국HCI학회 2020 한국HCI학회 학술대회 Vol.2020 No.2

요통환자의 공포-회피 반응검사(Fear Avoidance Belief Questionnaire; FABQ)와 요통 기능 장애 수준 검사(Oswestry Disability Index; ODI)를 통한 평가는 신체 기능장애 정도와 예후를 판단하는데 중요한 요인이다. 표면 근전도는 근 긴장도를 평가할 수 있는 도구로 카이로프랙터나 물리치료사가 환자의 진단 도구로 사용하고 있다. 이에 본 연구에서는 새로운 조이스틱형 표면 근전도 방법을 통한 심리사회적 수준 평가의 유용성을 검정하기 위해 장비의 검사-재검사 신뢰도와 타당도를 확인하고자 하였다. 본 연구를 통해 새로운 표면 근전도 방법은 요통환자의 요부 근활성도를 측정하는데 높은 신뢰수준을 확인할 수 있었으며 평가 변수들과의 유의한 상관관계를 보여 요통 환자가 겪는 심리사회적 문제를 평가하는데 타당도 높은 평가도구라 할 수 있겠다.

뒤넙다리근 능동과 수동신장 운동이 요통 환자의 골반 가동성에 미치는 영향

정승화 ( Seung-hwa Jung ),박대성 ( Dae-sung Park ) 대한물리의학회 2021 대한물리의학회지 Vol.16 No.1

PURPOSE: Hamstring muscle shortening is related to low back pain, and it is important to check the hamstring muscle flexibility and pelvic mobility to analyze the effects of the intervention. This study examined the effects of hamstring muscle shortening on flexibility and pelvic mobility according to the method of stretching the hamstring muscle in patients with low back pain. METHODS: Forty Low Back Pain Patients participated. The subjects performed the Visual Analogue Scale (VAS), Fear Avoidance Belief Questionnaire (FABQ), Korean version of Oswestry Disability Index (KODI), Myovision, and sensbalance therapy cushion (pelvic mobility, proprioception). The subjects were divided into two groups to perform the passive and active stretching protocol. The intervention was conducted three times a week for four weeks. RESULTS: Hamstring muscle flexibility was increased significantly in both groups (p < .05), and there was no difference between the groups. VAS, FABQ was decreased significantly in both groups (p < .01), and there was no difference between the groups. The left lower back muscle impedance was decreased significantly in both groups (p < .05). The passive stretching group showed a significant increase in the pelvic anterior, posterior, and left tilt ROM (p < .05). The active stretching group showed a significant increase in the pelvic anterior, posterior tilt ROM (p < .05). CONCLUSION: Both stretching methods may be useful intervention methods for pelvic mobility and pain recovery and can assess back pain recovery.