다구찌방법을 이용한 극돌기 고정기구의 최적설계

윤지환(Ji-Hwan Yun),이상수(Sang-Soo Lee),서은민(Eun-Min Seo),이영석(Young-Seok Lee),김광훈(Kwang-Hoon Kim),박성훈(Seong-Hun Park) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.춘계 No.-

호텔 멤버십제도의 효율적 운영 방안에 관한 연구

윤지환 ( Yun Ji Hwan ),박영기 ( Park Yeong Gi ),정삼술 ( Jeong Sam Sul ) 대한관광경영학회 2004 觀光硏究 Vol.18 No.2

For a hotel industry, the membership program is a way to admit new hotel members, make revenues by new membership fee, obtain sales of sutie and food and beverage for those with membership and increase sale. The main purpose of this research is to suggest the most effective process of rejoin ratio for membership after one year. Second purpose of this research is to suggest effective process of stabilizing rejoin ratio by membership character and active factor. Third purpose of this research is to research on efficient management of hotel membership program the previous studies on membership program an its current statues within the hotels in first class hotels in Seoul. The research result was the main purpose of the membership program was to hold importance market share to increase customer enrollment, to increase sale, increase revenue for more effective advertisement and to provide the customers with variety of services.

하이브리드 코팅시스템에 의해 제조된 Cr-Mo-Si-C-N 박막의 미세구조 및 기계적 특성연구

윤지환(Ji Hwan Yun),안성규(Sung Kyu Ahn),김광호(Kwang Ho Kim) 한국표면공학회 2007 한국표면공학회지 Vol.40 No.6

Cr-Mo-Si-C-N coatings were deposited on steel and Si wafer by a hybrid system of AIP and sputtering techniques using Cr, Mo and Si target in Ar/N₂/CH₄ gaseous mixture. Instrumental analyses of XRD and XPS revealed that the Cr-Mo-Si-C-N coatings must be a composite consisting of fine (Cr, Mo and Si)(C and N) crystallites and amorphous Si₃N₄ and SiC. The hardness value of Cr-Mo-Si-C-N coatings significantly increased from 41 GPa of Cr-Mo-C-N coatings to about 53 GPa with Si content of 9.3 at.% due to the refinement of (Cr, Mo and Si)(C and N) crystallites and the composite microstructure characteristics. A systematic investigation of the microstructures and mechanical properties of Cr-Mo-Si-C-N coatings prepared with various Si contents is reported in this paper.

임상연구 : Bonfils Intubation Fibrescope과 후두경을 이용한 기관내 삽관 시 혈압과 심박수 변화의 비교

윤지환 ( Ji Hwan Yun ),이덕희 ( Deok Hee Lee ) 대한마취과학회 2006 Korean Journal of Anesthesiology Vol.51 No.5

Background: The hemodynamic changes associated with orotracheal intubation may result from direct laryngoscopy and the endotracheal intubation. This study evaluated and compared the cardiovascular changes after either Bonfils intubation fiberscope or conventional laryngoscopic endotracheal intubation. Methods: Sixty patients, aged 20 to 30 years, were randomly allocated into two groups, the Bonfils intubation fiberscope group (BF group, n = 30) and conventional intubation using a rigid laryngoscope (LS group, n = 30). Bonfils intubation fiberscope or laryngoscopic oral endotracheal intubation was performed after inducing anesthesia. The systolic and diastolic arterial pressures, heart rate, peripheral oxygen saturation and intubation time were recorded before and after orotracheal intubation. Results: In both groups, the systolic and diastolic arterial pressures increased significantly after endotracheal intubation. The heart rate increased significantly after the induction of anesthesia in both groups. However, the arterial blood pressure, heart rate and intubation time were similar in both groups. Conclusions: The use of a Bonfils intubation fibrescope does not modify the hemodynamic response associated with endotracheal intubation compared with conventional laryngoscopy. (Korean J Anesthesiol 2006; 51: 547~51)

자기치유 공학재료

최은지(Eun Ji Choi),왕징(Jing Wang),윤지환(Ji Hwan Yoon),심상은(Sang Eun Shim),윤주호(Ju Ho Yun),김일(Il Kim) 한국청정기술학회 2011 청정기술 Vol.17 No.1

과학자와 공학자들은 끊임없이 금속, 합금, 고분자, 세라믹 등의 공학재료의 성질을 계속해서 변화하는 사회의 요구에 부응하는 방향으로 개선하여 왔다. 인조 공학재료는 일반적으로 기계적 성질이 우수하여, 자연 재료의 기계적 성질보다 우수한 경우가 많다. 그러나, 이와 같은 공학 재료는 자연계에서 흔히 볼 수 있는 자기치유능력, 즉 고의적인 인간의 접촉을 거치지 않고도 미세 균열을 제거하는 능력이 부족하다. 자연에서 관측할 수 있는 손상관리 패러다임은 여러 가지 종류의 공학재료의 고유 성질을 잘 고려하면 인조 공학재료에서도 성공적으로 재현할 수 있다. 특히 적절한 화학반응과 분자간력을 응용하면 고분자, 아이오노머, 복합체와 같은 유기재료에 적용할 수 있는 다양한 자기치유 방법을 개발할 수 있다. Scientists and engineers have altered the properties of materials such as metals, alloys, polymers, ceramics, and so on, to suit the ever changing needs of our society. Man-made engineering materials generally demonstrate excellent mechanical properties, which often far exceed those of natural materials. However, all such engineering materials lack the ability of selfhealing, i.e. the ability to remove or neutralize microcracks without intentional human interaction. The damage management paradigm observed in nature can be reproduced successfully in man-made engineering materials, provided the intrinsic character of the various types of engineering materials is taken into account. Various self-healing ptotocols that can be applied for the organic materials such as polymers, ionomers and composites can be developed by utilizing suitable chemical reactions and physical intermolecular interactions.

친환경 유기 소재로서 열가소성 탄성체의 오늘과 내일

최은지 ( Eun Ji Choi ),윤지환 ( Ji Hwan Yoon ),조정규 ( Jung Kyu Jo ),심상은 ( Sang Eun Shim ),윤주호 ( Ju Ho Yun ),김일 ( Il Kim ) 한국고무학회 2010 엘라스토머 및 콤포지트 Vol.45 No.3

열가소성 탄성체(thermoplastic elastomer, TPE)는 학술적 기초 및 응용은 물론이고 산업적, 상업적으로 매우 중요한 유기 소재의 하나이다. TPE는 블록 공중합체뿐만 아니라 많은 다른 고분자분야에서도 중요한 한 영역으로 생각할 수 있다. 가황 고무가 갖고 있는 성질과 열가소성 플라스틱이 보이는 성질을 동시에 갖고 있기 때문이다. 또한 블록과 그라프트 공중합체, 이들 혼합물, 가황 물질에서 비롯된 일련의 성질을 보여주기 때문이다. 이 소재의 중요성은 출판되는 간행물(논문, 특허, 보고서 등)의 수에서도 알 수 있다. `thermoplastic elastomer`를 키워드로, 열가소성 탄성체의 개념이 들어간 간행물의 숫자를 SciFinderScholar를 이용하여 조사한 결과, 1939년~2010년 7월 10일 사이에 18,508편에 이르렀으며, 특히 1990년 중반부터 그 숫자가 기하급수적으로 늘었다. 열가소성 플라스틱의 성질과 가교탄성체의 성질을 동시에 갖고 있는 TPE의 영역을 설명할 때 과학적, 기술적, 상업적인 관점을 모두 고려해야 한다. 본 보문에서는 TPE의 역사적인 관점을 먼저 설명하고, 화학적, 구조적 및 모폴러지 연구 동향을 다루고자 한다. 또한 주요 제조법과 현대적 분석 기술을 다룰 것이다. 이어 TPE의 성질과 가공성, 유기소재 사이에서의 입지와 응용에 대해도 분석한 후, 향후의 발전 방향에 대하여 논의하고자 한다. Much interest on the thermoplastic elastomers (TPEs) has recently been attracted in commercial fields as well as scientific and applied researches. The TPEs have their own characteristic area especially in relation with block copolymers as well as many other polymeric materials, since they show interesting features displayed by the conventional vulcanized rubber, and at the same time, by the thermoplastics. In addition, they are characterized by a set of interesting properties inherent to block and graft copolymers, variety of blends and vulcanized materials. The importance of TPE as organic materials can be evaluated by the number of published reports (papers, patents, technical reports, etc). The input of the concept `thermoplastic elastomer` to SciFinderScholar yields 18,508 results between 1939 and July 10, 2010, and the number increased exponentially after the mid of 1990. For the suitable introduction of the TPE, historic, scientific, technical and commercial considerations should be taken into account. This review article starts with a brief discussion on historical considerations, followed by a introduction of the main preparations and analytical techniques utilized in chemical, structural, and morphological studies. The properties, processing tools, the position among organic materials, and applications of TPEs are also briefly reviewed. Finally, the most probable trends of their future development are discussed in a short final remarks.

가열된 평판에서 원형 충돌제트의 열전달에 미치는 난류유동 특성의 영향

이계복 ( Kye Bock Lee ),윤지환 ( Ji Hwan Yun ) 충북대학교 산업과학기술연구소 2009 산업과학기술연구 논문집 Vol.23 No.1

An experimental study of jet impingement on the surface with linear temperature gradient is conducted with the presentation of the turbulent characteristics and the heat transfer rates measured when this jet impinges normal to a flat plate. The jet Reynolds number ranges from 10,000 to 70,000, the temperature gradient of the plate is 1.6~4.4 ℃ /cm and the dimensionless nozzle to plate distance(H/D) is from 4 to 12. The results show that the peak of heat transfer rate occurs at the stagnation point, and the heat transfer rate decreases as the radial distance from the stagnation point increases. A remarkable feature of the heat transfer rate is the existence of the second peak. This is due to the turbulent development of the wall jet. Maximum heat transfer rate occurs when the axial distance from the nozzle to nozzle diameter(H/D) is 6 or 8. It has been found that the heat transfer rate increases with increasing turbulent intensity. The numerical analysis using the CFD package FLUENT is executed to compare the experimental results and to find out whether the CFD package can be adopt for the design of impinging jet. CFD satisfactorily predicted performance of jet impingement.

카지노 리더⋅구성원의 교환관계가 잡크래프팅과 인게이지먼트에 미치는 영향

김용모(Yong-Mo Kim),윤지환(Ji-Hwan Yun) 한국관광학회 2024 관광학연구 Vol.48 No.2

지난 3년간 COVID-19의 영향으로 국내 대다수의 카지노 기업들에 천문학적 매출 손실과 더불어 핵심인력 유출, 조직 축소 현상 등이 발생하였다. 특히, 카지노 기업 내 핵심인력 유출 문제는 팬데믹 기간 동안 생존을 위해서 어쩔수 없는 선택이었다 할지라도, 엔데믹으로 접어드는 작금의 시기에 양질의 노동력 부재로 이어지고 있어 기업의 큰 고민거리로 대두되고 있다. 이러한 문제를 해결하기 위해서는 기업의 구성원이 자발적으로 일의 의미를 찾아 직무에 몰입해야 하며, 이를 감독하는 리더와 구성원의 관계 역시 제고되어야 할 것이다. 따라서, 이 연구의 목적은 카지노 리더⋅구성원간 교환관계(LMX)가 구성원의 잡크래프팅 및 인게이지먼트에 미치는 영향을 밝히고, 구성원의 핵심자기평가가 리더⋅구성원간 교환관계와 구성원의 잡크래프팅을 조절하는지 검증하고자 하였다. 이를 위하여 구조방정식을 활용하여 독립변수인 리더⋅구성원간 교환관계와 매개변수인 잡크래프팅, 종속변수인 인게이지먼트와의 관계를 파악하고, SPSS Process Macro의 model 4와 model 7을 이용하여 핵심자기평가의 조절효과를 분석하였다. 이 연구의 설문 대상은 국내 카지노 기업의 구성원들을 모집단으로 하였으며, 온라인과 오프라인 설문을 통해 2023년 7월 3일부터 7월 23일까지 3주일간 270부를 배포하여 최종 수집된 255부를 분석에 활용하였다. 연구 결과는 다음과 같다. 첫째, 카지노 리더⋅구성원간 교환관계는 구성원의 잡크래프팅에 영향을 미치는 것으로 나타났다. 둘째, 리더⋅구성원간 교환관계는 구성원의 인게이지먼트에 영향을 미치는 것으로 나타났다. 셋째, 구성원의 잡크래프팅은 인게이지먼트에 영향을 미치는 것으로 확인되었다. 또한, 리더⋅구성원간 교환관계와 인게이지먼트 간에 잡크래프팅의 매개효과도 확인하였다. 마지막으로 구성원의 핵심자기평가가 리더⋅구성원간 교환관계와 잡크래프팅간에 조절하는 것으로 파악되었다. 따라서, 카지노 기업들은 COVID-19 이후 인적자원의 향상을 위하여 리더⋅구성원간 교환관계 및 잡크래프팅, 핵심자기평가와 인게이지먼트 개념을 경영에 적용, 관리할 필요가 있다. Due to the impact of COVID-19 over the past three years, most casino companies in Korea have experienced a significant loss in sales, the departure of key personnel, and organizational downsizing. Particularly, the issue of key personnel leaving casino companies, while an inevitable survival strategy during the pandemic, now poses a major challenge for businesses due to the resulting shortage of high-quality labor. To address this issue, company members must find personal meaning in their work and fully engage with their responsibilities, and the relationship between leaders and the members they oversee should be strengthened. Thus, this study aimed to elucidate the effect of leader-member exchange (LMX) on members' job crafting and engagement, and to examine whether members' core self-evaluations moderate the relationship between LMX and job crafting. We employed structural equation modeling to analyze the relationship between the independent variable (leadermember exchange), the mediating variable (job crafting), and the dependent variable (engagement), and used SPSS Process Macro's model 4 and model 7 to analyze the moderating effect of core self-evaluation. The survey participants were employees of domestic casino companies, selected as the study population. Over three weeks, from July 3 to July 23, 2023, we distributed 270 surveys through both online and offline methods, and analyzed the 255 responses collected. The findings are as follows: First, LMX was shown to impact members' job crafting. Second, the job crafting of members was found to influence engagement. Third, LMX was found to affect members' engagement directly. Additionally, the mediating role of job crafting in the relationship between LMX and engagement was confirmed. Lastly, it was determined that members' core self-evaluation moderates the relationship between LMX and job crafting. Therefore, to enhance human resources post-COVID-19, casino companies should implement and manage the concepts of LMX, job crafting, core self-evaluation, and engagement within their management practices.

하이브리드 코팅시스템에 의해 제조된 Mo-Si-N 박막의 미세구조 및 기계적 특성연구

허수정(Su Jeong Heo),윤지환(Ji Hwan Yun),강명창(Myung Chang Kang),김광호(Kwang Ho Kim) 한국표면공학회 2006 한국표면공학회지 Vol.39 No.3

In this work, comparative studies on microstructure and mechanical properties between Mo₂N and Mo-Si-N coatings were conducted. Ternary Mo-Si-N coatings were deposited on AISI D2 steel substrates by a hybrid method, where AIP technique was combined with a magnetron sputtering technique. Instrumental analyses of XRD, HRTEM, and XPS revealed that the Mo-Si-N coatings must be a composite consisting of fine Mo₂N crystallites and amorphous Si₃N₄. The hardness value of Mo-Si-N coatings significantly increased from 22 GPa of Mo₂N coatings to about 37 GPa with Si content of 10 at.% due to the refinement of Mo₂N crystallites and the composite microstructure characteristics. The average friction coefficient of the Mo-Si-N coatings gradually decreased from 0.65 to 0.4 with increasing Si content up to 15 at.%. The effects of Si content on microstructure and mechanical properties of Mo-N coatings were systematically investigated.

다개층 식물생산 시스템의 재배선반 유동특성

류봉조(Bong-Jo Ryu),양윤영(Yun-Young Yang),김상활(Sang-Hwal Kim),정순배(Soon-Bae Jung),윤지환(Ji-Hwan Yoon) 한국소음진동공학회 2013 한국소음진동공학회 학술대회논문집 Vol.2013 No.4