Sn-CU계 다원 무연솔더의 미세구조와 납땜특성

김주연,배규식,Kim Ju-Youn,Bae Kyoo-Sik 한국재료학회 2005 한국재료학회지 Vol.15 No.9

To develope new lead-free solders with the melting temperature close to that of Sn-37Pb$(183^{\circ}C)$, Sn-0.7Cu-5Pb-1Ga, Sn-0.7Cu-5Pb-1Ag, Sn-0.7Cu-5Pb-5Bi-1Ag, and Sn-0.7Cu-SBi-1Ag alloys were composed by adding low-netting elements such as Ga, Bi, Pb, and Ag to Sn-0.7Cu. Then the melting temperatures, microstructures, wettability, and adhesion properties of these alloys were evaluated. DSC analysis showed that the melting temperature of Sn-0.7Cu-SPb-1Ga was $211^{\circ}C$, and those of other alloys was in the range of $192\~200^{\circ}C$. Microstructures of these alloys after heat-treatment at $150^{\circ}C$ for 24 hrs were basically composed of coarsely- grown $\beta-Sn$ grains, and $Cu_6Sn_5$ and $Ag_3Sn$ intermetallic precipitates. Sn-0.7Cu-5Pb-1Ga and Sn-0.7Cu-5Pb-5Bi-1Ag showed excellent wettability, while Sn-0.7Cu-5Bi-1Ag and Sn-0.7Cu-5Pb-5Bi-1Ag revealed good adhesion strength with the Cu substrates. Among 4 alloys, Sn-0.7Cu-5Pb-5Bi-1Ag with the lowest melting temperature $(192^{\circ}C)$ and relatively excellent wettability and adhesion strength was suggested to be the best candidate solder to replace Sn-37Pb.

에이전트 기반 유·무인 수색정찰 전술행위 모델링 및 분석

김주연,한상우,변재정,Kim, Ju Youn,Han, Sang Woo,Pyun, Jai Jeong 한국시뮬레이션학회 2018 한국시뮬레이션학회 논문지 Vol.27 No.4

오늘날 여러 산업분야에서 활용되고 있는 무인화기술은 자율기술이 성숙함에 따라 장기적으로는 인공지능차원의 자율판단이 가능한 수준으로까지 발전할 것으로 예상된다. 군사 분야에 있어 무인체계의 활용성을 높이기 위해서는 사람이 수행하던 임무를 무인체계가 대신함에 따른 효율성 및 효과의 정도를 체계적 정량적으로 분석하기 위한 기법 개발이 요구된다. 이에 본 논문에서는 유 무인체계가 혼합 편성된 미래 기갑수색부대가 수색정찰 임무계획 수립 시 대두되는 수색경로 대안을 효과적으로 분석할 수 있도록 전술행위를 규칙기반(rule-based)으로 표현하고, 유 무인 수색정찰 에이전트를 모델링하는 방법을 제안한다. 먼저, 기갑수색부대의 무인차량, 소형전술차량, 전투원 등 전투개체를 에이전트 개념으로 모델링하고, 각각의 기동, 탐색, 전투원 하차지점 선정, 경로선정 등을 행동규칙화 하여 NetLogo를 이용해 구현한다. 제안한 모델은 작전지역 내 기동로 여건, 적 위협 요소, 정찰자산 등을 고려하여 적정 경로를 선정하고, 경로상의 정찰면적, 정찰소요시간, 작전효과(기여도) 등의 산출이 가능하여, 향후 지상무인체계 효과 분석 시 다양한 목적으로 활용될 수 있을 것으로 기대된다. Today's unmanned technology, which is being used in various industries, is expected to be able to make autonomous judgements as autonomous technology matures, in the long run aspects. In order to improve the usability of unmanned system in the military field, it is necessary to develop a technique for systematically and quantitatively analyzing the efficiency and effectiveness of the unmanned system by means of a substitute for the tasks performed by humans. In this paper, we propose the method of representing rule-based tactical behavior and modeling manned and unmanned reconnaissance agents that can effectively analyze the path alternatives which is required for the future armored cavalry to establish a reconnaissance mission plan. First, we model the unmanned ground vehicle, small tactical vehicle, and combatant as an agent concept. Next, we implement the proposed agent behavior rules, e.g., maneuver, detection, route determination, and combatant's dismount point selection, by NetLogo. Considering the conditions of maneuver, enemy threat elements, reconnaissance assets, appropriate routes are automatically selected on the operation area. It is expected that it will be useful in analyzing unmanned ground system effects by calculating reconnaissance conducted area, time, and combat contribution ratio on the route.

Curcuma longae Radix, Phellinus linteus 및 Scutellariae Radix 혼합추출물의 $A{\beta}$ (25-35) 유도 배양신경세포독성 및 마우스기억손상 억제효과

김주연,정하연,반주연,유재국,배기환,성연희,Kim, Joo-Youn,Jeong, Ha-Yeon,Ban, Ju-Yeon,Yoo, Jae-Kuk,Bae, Ki-Hwan,Seong, Yeon-Hee 한국약용작물학회 2009 한국약용작물학회지 Vol.17 No.6

The present study investigated an ethanol extract (HS0608) of a mixture of three medicinal plants of Curcuma longae radix, Phellinus linteus, and Scutellariae radix for possible neuroprotective effects on neurotoxicity induced by amyloid $\beta$ protein ($A{\beta}$) (25-35) in cultured rat cortical neurons and antidementia activity in mice. Exposure of cultured cortical neurons to $10\;{\mu}M$ $A{\beta}$ (25-35) for 36 h induced neuronal apoptotic death. At $1-50\;{\mu}g/m{\ell}$, HS0608 inhibited neuronal death, elevation of intracellular calcium concentration ($[Ca^{2+}]_i$), and generation of reactive oxygen species (ROS) induced by $A{\beta}$ (25-35) in primary cultures of rat cortical neurons. Memory loss induced by intracerebroventricular injection of ICR mice with 15 nmol $A{\beta}$ (25-35) was inhibited by chronic treatment with HS0608 (25, 50 and 100 mg/kg, p.o. for 7 days) as measured by a passive avoidance test. From these results, we suggest that the antidementia effect of HS0608 is due to its neuroprotective effect against $A{\beta}$ (25-35)-induced neurotoxicity and that HS0608 may have a therapeutic role in preventing the progression of Alzheimer's disease.

표면마무리를 위한 Sn-2.5Cu 합금 도금막의 특성

김주연,배규식,Kim, Ju-Youn,Bae, Kyoo-Sik 한국재료학회 2003 한국재료학회지 Vol.13 No.2

Sn-2.5Cu alloy layers were deposited on the Alloy 42 lead-frame substrates by the electroplating method, and their microstructures, adhesion strength, and electrical resistivity were measured to evaluate the applicability of Sn-Cu alloy as a surface finishing material of electronic parts. The Sn-2.5Cu layers were electroplated in the granular form, and composed of pure Sn and Cu$_{6}$Sn$_{5}$ intermetallic compound. Surfaces of the electroplated Sn-2.5Cu layers were rather rough and also the thickness variance was large. The adhesion strength of the Sn-2.5Cu electroplated layers was highly comparable to that of the electroplated Cu alloy layer and the electrical conductivity was about 10 times higher than the pure Sn. After the 20$0^{\circ}C$ 30 min. annealing of the electroplated Sn-2.5Cu layers, the surface roughness was reduced, and adhesion strength and conductivity were improved. These results showed the Sn-Cu alloys can be used as an excellent surface finishing material.ial.

학령기 아동의 스트레스와 대처행동에 관한 연구

김주연,김정순,Kim, Ju-Youn,Kim, Jung-Soon 한국지역사회간호학회 1999 지역사회간호학회지 Vol.10 No.1

The purpose of this study was to investigate the daily stress and stress coping behavior of elementary school children. The subjects for this study were 372 children fourth, fifth and sixth graders from an elementary school in Pusan. We adopted Won - Joo Chung's research instrument (1997) for measuring stress and coping behavior in this study. Statistical techniques such as frequency, percentage, mean, standard deviation, order, and Pearson correlation were used to examine the research questions of this study. The results of this study were as follows: 1. The most common instance of stress to be experienced by all children was the stress from school life, followed by social pressures, individual pressures and family environment. 2. A positive revaluation was the most commonly used stress-coping behavior, followed by behavioral mood conversion, spiritual support, problem-facing behavior, an information search for problem-solving, physical separation for emotional relaxation, avoidance, emotional aggressiveness and emotional expression. 3. Stress-coping behavior had a positive and significant correlation with the stress score(r = .4391, p= .000). In conclusion, the stress from school life was the most common experienced by all children. While independent effort in problem-solving was unsufficient, stress coping behavior had positive results. Therefore, this study verified the necessity of minimizing the stress children experience from school life and of helping them attain desirable stress-coping behaviors.

Moutan Cortex Extract Inhibits Amyloid ${\beta}$ Protein (25-35)-induced Neurotoxicity in Cultured Rat Cortical Neurons

김주연,주현수,반주연,송경식,성연희,Kim, Joo-Youn,Ju, Hyun-Soo,Ban, Ju-Yeon,Song, Kyung-Sik,Seong, Yeon-Hee The Korean Society of Medicinal Crop Science 2008 한국약용작물학회지 Vol.16 No.6

Moutan cortex, the root bark of Paeonia suffruticosa Andrews (Paeoniaceae), has pharmacological effects such as anti-inflammatory, antiallergic, analgesic and antioxidant activities. We investigated a methanol extract of Moutan cortex for neuroprotective effects on neurotoxicity induced by amyloid ${\beta}$ protein ($A{\beta}$) (25-35) in cultured rat cortical neurons. Exposure of cultured cortical neurons to $10\;{\mu}M\;A{\beta}$ (25-35) for 24 h induced neuronal apoptotic death. Moutan cortex inhibited $10\;{\mu}M\;A{\beta}$ (25-35)-induced neuronal cell death at 30 and $50\;{\mu}g/m{\ell}$, which was measured by a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay and Hoechst 33342 staining. Moutan cortex inhibited $10\;{\mu}M\;A{\beta}$ (25-35)-induced elevation of intracellular calcium concentration ($[Ca^{2+}]_i$), and generation of reactive oxygen species (ROS) which were measured by fluorescent dyes. Moutan cortex also inhibited glutamate release into medium induced by $10\;{\mu}M\;A{\beta}$ (25-35), which was measured by HPLC. These results suggest that Moutan cortex prevents $A{\beta}$ (25-35)-induced neuronal cell damage by interfering with the increase of $[Ca^{2+}]_i$, and then inhibiting glutamate release and ROS generation. Moutan cortex may have a therapeutic role in preventing the progression of Alzheimer's disease.

발반사 마사지가 여대생의 생리통 및 월경전증후군 완화에 미치는 효과

김주연 ( Ju Youn Kim ) 한국미용학회 2007 한국미용학회지 Vol.13 No.2

Premenstrual syndrome is a common gynecological disorder which is experienced by more than 50% of female during the menstruation period and five to ten days earlier than the period in which women become easily tired and feel depressed or experience physical symptoms such as headache and stomach ache. These symptoms usually start at one`s late 10`s or early 20`s, and especially women in their 20`s complain more of the symptoms than women in other ages, and have stronger pains which become serious stress in their daily life. Suggested causes behind the symptoms are reported as psychological factors such as stress, character-related elements, and attitude to menstruation, physiological factors such as hormone imbalance, saline concentration, dietary factors such as nutritional imbalance, and nutritional factors such as lack in Vitamin and mineral intake. This research attempts to provide basic documents showing how to relive premenstrual symptoms through applying foot reflexology in a clinical situation while looking into menstrual cramps, premenstrual symptoms of female college students, and to present practical documents which can help giving a proper response to a periodic cycle of females. This is effect of foot reflexology on menstrual cramps and premenstrual symptoms showed following results. After subjects receiving foot reflexology, points in the menstrual cramps category decreased significantly, and points of behavioral changes(p<0.001), negative feelings (p<0.001), pains(p<0.001), concentration ability(p<0.001), water retention(p<0.001), autonomic nervous system responses(p<0.001), gastrointestinal changes(p<0.001), changes in skin(p<0.001) from premenstrual symptom category also showed considerable decrease(p<0.001).

산림치유 적용이 중년 여성의 갱년기 자각 정도에 따른 갱년기 완화 및 정신건강 회복에 미치는 영향

김주연(Ju-youn Kim),신창섭(Chang-sup Shin),연평식(Poung-sik Yeoun),조미나(Mi-na Jo) 한국산림휴양복지학회 2015 한국산림휴양학회 학술발표회 자료집 Vol.2015 No.4

분사노즐 출구 각도 변화가 분사특성에 미치는 영향에 관한 계산적 고찰

김주연(Ju Youn Kim),박권하(Kweon Ha Park),이승호(Seung Ho Lee) 한국마린엔지니어링학회 2012 한국마린엔지니어링학회지 Vol.36 No.8

모발 염색과 부작용 실태 조사 연구

김주연 ( Ju-youn Kim ),송연숙 ( Yeon-sook Song ),이근광 ( Keun-kwang Lee ) 대한미용문화예술학회 2017 대한미용문화예술학회지 Vol.6 No.2

This study was conducted from 25 September, 2016 to 20 October, 2016 on a total of 427 individuals who live all over Korea. The results of the analysis are as follows. 82.9% of the respondents had currently dyed hair, and when asked on why they had dyed their hair, the most frequent response was in order to bring about a change of image at 48.0% while the next frequent response was to hide graying hair at 29.8%, followed by to refresh oneself at 18.3%. The method in which the respondents dyed their hair most frequently was through a beauty parlor(44.3%). It was followed by self-dyeing + beauty parlor(33.0%) and self-dyeing came last (14.8%). The most frequently chosen reason for self-dyeing was its inexpensive cost at 49.5%. The next frequent reason was that it did not have time limits. The reasons for dyeing one’s hair at a beauty parlor were, comfort at 41.5%, more trustworthy as an expert is tailoring the hair color to match one’s image(24.8%) and one can express a greater variety of colors(17.6%). The ratio of respondents who experienced side effects after dyeing their hair was 29.0%. The most frequent form of side effects was itchiness at 59.6%. The next type of side effect was 22.8%.