플립칩 패키지의 신뢰성 향상에 관한 연구

이선병(Sun Byung Lee),김종민(Jong Min Kim),이성혁(Seong Hyuk Lee),신영의(Young Eui Shin) 한국생산제조학회 2007 한국공작기계학회 춘계학술대회논문집 Vol.2007 No.-

A solder joint fatigue failure of flip chip (FC) package is mainly caused by the thermal stress due to the coefficient of thermal expansion (CTE) mismatch between the silicon die and the substrate. A nonlinear finite element analysis was conducted to investigate solder joint reliability under thermal cycling loading for FC assemblies without and with underfill. The effect of the solder joint height and thermomechanical properties such as CTE and Young's modulus on reliability of FC package. For parametric study, a finite element analysis are performed for seven different CTEs and five different Young's moduli of underfill. The concentrated Von Mises stress of the underfilled FC assembly was approximately 85% comparing that of FC assembly without underfill. Also, the concentrated stresses in the solder joint was decreased with increasing solder joint height. In addition, it is found that the solder joint reliability was improved with increasing Young's Modulus of underfill. Furthermore, the solder joint reliability was improved as the CTE was close to that of solder.

간세포암의 고주파 열치료 후 천자침 경로를 통한 전이 1례

조영완,박석주,진한영,김준영,이재익,강명주,박정하,윤정희,박성재,지삼룡,이연재,이상혁,설상영 인제대학교 2006 仁濟醫學 Vol.27 No.-

Radiofrequency ablation(RFA), as a form of minimally invasive therapy for hepatocellular carcinoma, has become an important treatment modality. Because of limitation of surgery, RFA has become standard therapy for hepatocellular carcinoma in some situations. But there are some complications of RFA such as bleeding, infection, hematoma, adjacent organ thermal damage including intestinal perforation, needle track seeding, and so on. There are few reports in the literature that systematically evaluate the incidence of needle tract seeding and its associated risk factors. And only 2 cases of needle tract seeding of hepatocellular carcinoma after RFA were reported in Korea. We report a case of needle tract seeding of hepatocellular carcinoma after RFA.

A case of self-healing juvenile cutaneous mucinosis

( In Hyuk Kwon ),( Dae Yeon Kim ),( Dong Won Lee ),( Tae Hyung Ryu ),( Jae Eun Choi ),( Soo Hong Seo ),( Young Chul Kye ),( Hyo Hyun Ahn ) 대한피부과학회 2016 대한피부과학회 학술발표대회집 Vol.68 No.1

Self-healing juvenile cutaneous mucinosis is a very rare, self-limiting disease characterized by transient cutaneous lesions that affects the young. This disorder is characterized by rapid onset of asymptomatic papules and nodules on the face, periarticular regions, abdomen, and thigh. As implied by the name, the lesions spontaneously resolve over weeks to months. In contrast to mucinoses affecting adults, Self-healing juvenile cutaneous mucinosis has not been associated with systemic disorders such as paraproteinemia, bone marrow plasmacytosis, or thyroid diseases. A 7-year-old male presented with erythematous papules, multiple subcutaneous nodules on trunk and both arms that began 6 days before. Aside from pruritus of lesions no other symptoms were manifested. Histopathology showed microabscess in epidermis, superficial perivascular lymphocytic infiltration, and mucin deposition in dermis On follow up visit, although new lesions were present, previous lesions were subsiding. In consideration of the clinicopathological features, the diagnosis of self-healing juvenile cutaneous mucinosis was made. The patient is under close observation with no specific treatment. Herein, we report a rare case of self-healing juvenile cutaneous mucinosis. Knowledge of this entity may prevent unnecessary diagnostic testing and aggressive treatment in the pediatric population with this self-limited disease.

Trichophyton verrucosum infection in Korea: Analysis on 224 patients from 1976 to 2015

( Dong Hyuk Eun ),( Jun Hong Park ),( Sun Young Moon ),( Yong Hyun Jang ),( Seok-jong Lee ),( Do Won Kim ),( Yong Jun Bang ),( Jae Bok Jun ),( Weon Ju Lee ) 대한피부과학회 2016 대한피부과학회 학술발표대회집 Vol.68 No.2

Background: Trichophyton (T.) verrucosum is a dermatophyte causing ringworm in cattle, distributed worldwide. It can be responsible for various inflammatory lesions of skin and scalp. In Korea, kerion celsi caused by T. verrucosum was first reported at 1986 in the southeast province of Korea. Since then, many patients infected with T. verrucosum have been reported in Young-nam province. There are few long-term studies about epidemiological characteristics of T. verrucosum. Objectives: To investigate the clinical and epidemiological characteristics of T. verrucosum infections in Korea. Methods: A total of 224 patients were diagnosed as T. verrucosum infection by fungal culture from 1976 to 2015. The data were based on a retrospective survey of medical records. Results: The annual incidence of patients with T. verrucosum infection had been increasing since the report in 1986. The number of patients showed a peak in 1988. After 2000, the number of patients had been decreasing. Female to male ratio showed a 1.2-fold predominance of female infection. And more than 15-year-old group was 59.4% of total patients. T. verrucosum infection was most commonly seen in spring and was found predominantly in patients living in rural areas. Face was most frequently involved, followed by arms. Conclusion: These findings provide useful information for understanding of T. verrucosum infection and future dermatophytosis prospects.

보육교사의 그릿과 직무만족도 관계에서 교사효능감의 매개효과

강신영(Kang, Sin­young),문혁준(Moon, Hyuk­Jun) 학습자중심교과교육학회 2019 학습자중심교과교육연구 Vol.19 No.17

본 연구는 보육교사의 그릿과 교사효능감, 그리고 직무만족도 간의 관계에서 관련성을 살펴보고 그릿과 직무만족도 관계에서 교사효능감의 매개효과가 어떠한지 알아보고자 한다. 연구대상은 서울과 수도권 지역에 소재한 어린이집에 근무하는 보육교사 495명이다. 연구를 위해 SPSS-WIN 25.0를 사용하여 각 변인들의 기술통계와 Pearson의 상관분석을 실시하였고, 매개효과를 검증하기 위하여 AMOS 18.0를 사용하여 매개 모형 분석을 실시하였다. 연구결과는 다음과 같다. 첫째, 보육교사의 그릿, 교사효능감, 직무만족 세 변인 간에 정적인 상관관계를 보였다. 둘째, 보육교사의 그릿은 매개변인인 교사효능감을 통해서 직무만족도에 영향력을 보여 완전 매개효과가 있는 것으로 나타났다. 따라서 본 연구는 최근들어 중요한 변인으로 주목받고 있는 그릿이 교사효능감을 거쳐 보육교사의 직무만족을 강하게 예측하는 심리적인 특성임을 밝혀냈다는 점에서 연구의 의의를 갖는다. This study examine the relevance between Teachers Grit, Efficacy and Job satisfaction, and search what the mediating effect of teachers efficacy is in the relevance between Grit and the job satisfaction. The objects of study are 495 teachers who work in the daycare center located in Seoul and the capital area. For this research, the technical statistics of each variables and Pearson s correlation analysis using SPSS-WIN 25.0 are conducted, and the mediated model analysis using AMOS 18.0 is conducted for validating the mediated effect. The results of study are given as follows. First, it showed a static correlation between three variables, Teachers Grit, Teachers efficacy and the job satisfaction. Second, Teachers Grit appeared the influence in the job satisfaction through Teachers efficacy as the mediated variable, so, it turned out to be the full mediating effect. Therefore, this study means that Grit which receive attention as a significant variable in these days is psychological character as strongly predicting Teachers Job satisfaction through Teachers efficacy.

Effect of Random Poisson's Ratio on the Response Variability of Composite Plates

Noh, Hyuk-Chun,Yoon, Young-Cheol Computational Structural Engineering Institute of 2010 한국전산구조공학회논문집 Vol.23 No.6

Together with the Young's modulus the Poisson's ratio is another independent material parameter that governs the behavior of a structural system. Therefore, it is meaningful to evaluate separately the influence of the parameter on the random response of the structural system. To this end, a formulation dealing with the spatial randomness in the Poisson's ratio in laminated composite plates is proposed. The main idea of the paper is to transform the fraction form of the constitutive coefficients into the expanded form in an ascending order of the stochastic field function. To validate the adequacy of the formulation, a square plate is chosen and the computation results are compared with those obtained using conventional Monte Carlo simulation. It is observed that the results show good agreement with those by the Monte Carlo simulation(MCS).

발성을 병행한 과제수행이 상지 움직임에 미치는 영향

박지혁(Ji-Hyuk Park),유은영(Eun-Young Yoo) 한국언어치료학회 2005 言語治療硏究 Vol.14 No.3

This study examined the effects of vocalization on upper extremity motion during carrying a cup in healthy people.Experiments were performed on 26 healthy young-adult subjects with right hand dominance. They had no medical history of neurological problems with their upper extremities. The task was to reach for and grasp a cup placed on a table in front of them and then place the cup on a makeshift cabinet shelf with and without vocalization. The vocalization consisted of saying Ah while carrying the cup. We used a 3-D analysis system called CMS-70P to analyze the motion at the peak of the angular velocity, the change in acceleration, and the time to the peak velocity of the elbow while recording the performance time. We found that vocalization increased the peak velocity (p<0.05), shortened the time to the peak velocity (p>0.05), and reduced the change in acceleration((p<0.05) of dominant arm (right side), while it lengthened the time to the peak velocity (p>0.05), and increased the change in acceleration(p>0.05) of non-dominat arm (left side). In summary, vocalization made the motion of the dominant arm positive.

Three-Dimensional Polymeric Mechanical Metamaterials Fabricated by Multibeam Interference Lithography with the Assistance of Plasma Etching

Kang, Da-Young,Lee, Wooju,Kim, Dongchoul,Moon, Jun Hyuk American Chemical Society 2016 Langmuir Vol.32 No.33

<P>The pentamode structure is a type of mechanical metamaterial that displays dramatically different bulk and shear modulus responses. In this study, a face-centered cubic (FCC) polymeric microstructure was fabricated by using SU8 negative type photoresists and multibeam interference exposure. Isotropic plasma etching is used to control the solid-volume fraction; for the first time, we obtained a structure with the minimum solid-volume fraction as low as 15% that still exhibited high structural integrity. Using this method, we reduced the width of atom-to-atom connections by up to 40 nm. We characterize the effect of the connection area on the anisotropy of the mechanical properties using simulations. Nanoindentation measurements were also conducted to evaluate the energy dissipation by varying the connection area. The Young's/shear modulus ratio is 5 times higher for the etched microstructure than that of the bulk SU8 materials. The use of interference lithography may enable the properties of microscale materials to be engineered for various applications, such as MEMS.</P>

서울의 Penicillinase Producing Neisseria Gonorrhoeae 발생빈도(1994)

김재홍,안진균,정성재,김영태,김중환,김시영,이석종,이홍렬,서호석,김경훈,권혁진,정우권,고우석,이용석,안필수,오준규,오용섭 대한화학요법학회 1996 대한화학요법학회지 Vol.14 No.1

Background : In recent years gonorrhoea has been panendemic and remains one of the most common Sexually Transmitted Diseases in the world, especially in developing countries. Objective & Method : For the detection of a more effective therapeutic regimen and assessing the prevalence of Penicillinase Producing Neisseria Gonorrhoeae(PPNG), Ive have been trying to study the patients who have visited the VD Clinic of Choong-Ku Public Health Center in Seoul since 1980 by means of the chromogenic cephalosporin method. Results : In 1994, 168 strains of N. gonorrhoeae were isolated, among which 109 (64,9% ) were PPNG. Conclustion : Our results suggests that the prevalence of PPNG in Seoul is still increasing.

산업자재용 폴리에스터 섬유의 강도 향상에 관한 연구

박영신,남영식,정상영,최재호,장기혁,박원호,Park, Young-Shin,Nam, Young-Sik,Jung, Sang-Young,Choi, Jae-Ho,Jang, Ki-Hyuk,Park, Won-Ho 한국섬유공학회 2012 한국섬유공학회지 Vol.49 No.1

In this work, effects of total draw ratio change on the mechanical properties of polyester fibers were studied. The process parameter was a total draw ratio and the draw ratios that were used ranged from 6.6 to 7.0. Tensile properties are determined from the tensile tester, and crystallite parameters from the density measurement and X-ray diffraction were discussed with the different total draw ratios. The tenacity, young's modulus and crystallinity were increased to 10.6 g/d, 123.2 g/d and 42.1%, respectively, with increase in the total draw ratio. The relations between total draw ratio and mechanical properties of high tenacity polyester fiber were discussed.