Piezoelectric composite films which are enabled by inorganic piezoelectric nanomaterials-embedded polymer, have attracted enormous attention as a sustainable power source for low powered electronics, because of their ease of fabrication and flexible nature. However, the absorption of applied stress by the soft polymeric matrices is a major issue that must be solved to expand the fields of piezoelectric composite applications. Herein, a flexible and porous piezoelectric composite (piezoelectric sponge) comprised of BaTiO3 nanoparticles and polydimethylsiloxane was developed using template method to enhance the energy conversion efficiency by minimizing the stress that vanishes into the polymer matrix. In the porous structure, effective stress transfer can occur between the piezoelectric active materials in compression mode due to direct contact between the ceramic particles embedded in the pore-polymer interface. The piezoelectric sponge with 30 wt% of BaTiO3 particles generated an open-circuit voltage of ~12 V and a short-circuit current of ~150 nA. A finite element method-based simulation was conducted to theoretically back up that the piezoelectric output performance was effectively improved by introducing the sponge structure. Furthermore, to demonstrate the feasibility of pressure detecting applications using the BaTiO3 particles-embedded piezoelectric sponge, the composite was arranged in a 3 × 3 array and integrated into a single pressure sensor. The fabricated sensor array successfully detected the shape of the applied pressure. This work can provide a cost-effective, biocompatible, and structural strategy for realizing piezoelectric composite-based energy harvesters and self-powered sensors with improved energy conversion efficiency

To make a satisfactory decision regarding project scheduling, a trade-off between the resource-related cost and project duration must be considered. A beneficial method for decision makers is to provide a number of alternative schedules of diverse project duration with minimum resource cost. In view of optimization, the alternative schedules are Pareto sets under multi-objective of project duration and resource cost. Assuming that resource cost is closely related to resource leveling, a heuristic algorithm for resource capacity reduction (HRCR) is developed in this study in order to generate the Pareto sets efficiently. The heuristic is based on the fact that resource leveling can be improved by systematically reducing the resource capacity. Once the reduced resource capacity is given, a schedule with minimum project duration can be obtained by solving a resource-constrained project scheduling problem. In HRCR, VNS (Variable Neighborhood Search) is implemented to solve the resource-constrained project scheduling problem. Extensive experiments to evaluate the HRCR performance are accomplished with standard benchmarking data sets, PSPLIB. Considering 5 resource leveling objective functions, it is shown that HRCR outperforms well-known multi-objective optimization algorithm, SPEA2 (Strength Pareto Evolutionary Algorithm-2), in generating dominant Pareto sets. The number of approximate Pareto optimal also can be extended by modifying weight parameter to reduce resource capacity in HRCR.

본 연구는 광화문 월대로 사용된 석재를 대상으로 암석학적 연구를 활용한 석재공급지를 추정하기 위해 수행되었다. 월대는 2010년에 일부 구간이 다시 복원된 것으로 원부재인 담홍색 화강암과 신석재인 회백색 화강암이 사용되었다. 석재공급지 추정을 위해 북한산과 수락산의 지질조사를 수행하였으며 채취한 시료는 모두 담홍색 화강암과 유사한 특징을 보였다. 전암대자율은 북한산에 비해 수락산의 값이 크고 암석의 색에서 부분적인 차이를 보이지만 수락산이 상대적으로 선명한 담홍색을 띤다. 수락산은 월대에 사용된 원부재와 비슷한 암석기재적 특징, 전암대자율, 역사적 사료 그리고 야외조사 시 발견된 채석흔적 등을 통해 최종 복원용 석재공급지로 판단된다. 물성시험 결과, 월대 원부재는 풍 화로 인해 147 MPa로 다소 낮은 수치를 보이며 석재공급지로 생각되는 수락산은 244 MPa 높은 값을 보여 안정성까지 확보되어 양질의 석재로 사용 가능하다. 수락산 일대는 주거지역이 일부 포함 되어 있어 행정적인 문제, 자연파괴, 인근 주민 생활권 침해가 발생하여 채석활동은 어렵다. 또 다른 대안으로 QAP조성, 광물조직, 암색 등의 암석학적특징 및 물리적 특성까지 유사한 중-조립질 담홍색화강암의 포천 창수석과 영중석을 제안할 수 있다.

본 연구는 비만여대생을 대상으로 섭식제한(DG), 유산소운동(EG), 섭식제한과 유산소운동 (DEG) 그룹으로 나누어 체중, 비만의 개선, 혈중지질성분 및 대사성위험요인에 미치는 영향을 분석하였다. 실험은 8주간 주 5회 실시하였으며, DG는 1일 에너지 섭취열량을 300㎉를 제한하였고, EG는 런닝 머신을 이용하여 300㎉를 소비시켰으며, DEG는 각각 150㎉를 제한과 소비시켰다. 결과, 신체조성의 경우 DG에서는 체중(p<.011), BMI(p<.008)가 감소하였고, EG와 DEG에서는 체중(p<.044, p<.017), 체지방량(p<.047, p<.018), BMI(p<.03, p<.008), 체지방률(p<.036, p<.015), WHR(p<.049, p<.027)이 유의하게 감소하였다. 혈중지질성분은 DG에서 HDL-C(p<.028), EG에서 TG(p<.038), DEG에서는 TC(p<.014), LDL-C(p<.007)에서 유의하게 감소하였다. 대사성위험요인은 DG에서 HOMA-IR (p<.035), leptin(p<.007), EG에서 FBG(p<.043), leptin(p<.003), DEG에서 FBG(p<.014), insulin (p<.005), HOMA-IR(p<.005), leptin(p<.016), resistin(p<.040)에서 유의한 차이가 나타났다. 따라서 본 연구의 결과로부터 비만여대생들이 섭식제한, 유산소운동의 단독처치보다 섭식제한과 유산소운동을 병행 하는 것이 신체조성, 혈중지질성분, 대사성위험요인의 개선에 가장 효과가 있을 것으로 판단된다.

Lee Hye-yong. Sok So-hyune･Park Song-chol･Bak Yong-ik･Lee Jeong-woo･Jin Jeongkun ･Jeoung Yeon-ok. 2016. “How members of a medical center communicate with each other”. The Sociolinguistic Journal of Korea 24(1). 213~239. The purpose of this article is to give an overview of the organizational communication in the medical center. This overview is based on the results of the individual studies conducted from 2012 to 2015 within a project about organizational communication in the medical center. Firstly we will summarize the characteristics of the respective communications performed between physicians, nurses, administrative staffs and between physicians and nurses. From those characteristics we will generalize the four typical negative aspects of the organizational communication in the medical center: authoritative, lack of empathy, an air of indifference to the communication, respectless. And then we introduce the causes of the negative aspects and their influences on the staffs of the medical center. Lastly we discuss how to improve the organizational communication in the medical center.

본 논문에서는 FSI해석을 이용하여 비정형 초고층 빌딩의 풍응답 특성을 연구하였다. 해석모델은 Twist모델이며, 뒤틀림 각도와 풍가속도의 상관관계에 대해 연구 중점을 두었다. 먼저 단방향 해석을 수행하여 100년 재현주기 풍속에 대한 최대 횡 변위를 구하고, 제한조건을 만족하는 탄성계수를 산출한다. 그리고 양방향 해석을 수행, 시간이력해석을 통해 산출된 탄성계수와 임의의 밀도를 가지는 풍가속도를 예측하게 된다. 정방형 모델은 높이 400m, 변장비 1:1, 세장비 8로 설정, 뒤틀림 모델은 0도에서 90도까지 15도 간격으로, 90도에서 360도까지 90도 간격으로 비틀어 회전시켰다. 형상에 따른 풍가속도 예측결과, 정방형 모델이 뒤틀림 모델보다 크게 산출되어 풍진동 영향에 더 민감한 것을 검증하였다.

본 연구는 인피섬유만을 사용하여 한지를 제조함에 따라 폐기되어지는 닥나무 목질부로 세라믹을 제조하여 기능성 한지의 첨가제로 이용하기 위해 연구한 결과는 다음과 같다. 다양한 조건에서 제조된 닥나무 세라믹을 첨가한 한지의 원적외선 방사율 및 방사에너지는 수지함침율과 탄화온도가 높을수록 저하되었고 세라믹의 첨가량이 증가할수록 상승하였으며, 세라믹의 첨가로 90% 이상의 비교적 높은 방사율을 나타내었다. 또한 세라믹 한지의 포름알데히드에 대한 탈취율은 수지 함침율과 탄화온도가 높을수록 점차 감소하였지만 세라믹의 첨가량이 증가할수록 상승하여 전체적으로 70% 이상의 의미 있는 탈취율을 나타내었다.

본 연구는 우리나라의 전통문화인 한지의 다양한 용도를 개발하고, 인피섬유를 주원료로 하는 한지의 특성상 폐기되어져 왔던 닥나무 목질부를 이용하여 기능성 재료인 세라믹의 제조 및 한지벽지에 이용되는데 기초 자료를 제공하고자 하였으며 다음과 같은 결론을 얻었다. 다양한 조건에서 제조된 닥나무 세라믹을 첨가한 수초지는 세라믹 제조 시의 수지함침율, 탄화온도 및 세라믹의 첨가량에 따라 전반적인 물리적 성질은 감소하였으나 인열지수는 거의 변화가 없었다. 또한 투기도의 경우에서는 세라믹이 닥섬유의 섬유결합을 저해하여 크게 증가하였다. 한편, 한지벽지로서 습윤인장강도, 일광견뢰도, 습윤마찰견뢰도, 은폐성 등은 KS 벽지 규격을 만족시켰으나 건조마찰견뢰도는 규격에 미달되어 이에 대한 보완이 요구되었다. 따라서 폐기성 닥나무 목질부를 활용하여 세라믹을 제조 및 한지벽지에 이용함으로서 닥나무 목질부의 다양한 활용도 개발과 양호한 품질의 한지벽지를 제조하는데 충분한 가능성을 확인하였다.

3-D IC integration enables the smallest form factor and highest performance due to the shortest and most plentiful interconnects between chips. Direct metal bonding has several advantages over the solder-based bonding, including lower electrical resistivity, better electromigration resistance and more reduced interconnect RC delay, while high process temperature is one of the major bottlenecks of metal direct bonding because it can negatively influence device reliability and manufacturing yield. We performed quantitative analyses of the interfacial properties of Al-Al bonds with varying process parameters, bonding temperature, bonding time, and bonding environment. A 4-point bending method was used to measure the interfacial adhesion energy. The quantitative interfacial adhesion energy measured by a 4-point bending test shows 1.33, 2.25, and 6.44 J/m2 for 400, 450, and 500˚C, respectively, in a N2 atmosphere. Increasing the bonding time from 1 to 4 hrs enhanced the interfacial fracture toughness while the effects of forming gas were negligible, which were correlated to the bonding interface analysis results. XPS depth analysis results on the delaminated interfaces showed that the relative area fraction of aluminum oxide to the pure aluminum phase near the bonding surfaces match well the variations of interfacial adhesion energies with bonding process conditions.

The effect of annealing treatment conditions on the interfacial adhesion energy between electrolessplated Ni film and polyimide substrate was evaluated using a 180˚ peel test. Measured peel strength values are 26.9±0.8, 22.4±0.8, 21.9±1.5, 23.1±1.3, 16.1±2.0 and 14.3±1.3g/mm for annealing treatment times during 0, 1, 3, 5, 10, and 20 hours, respectively, at 200˚C in ambient environment. XPS and AES analysis results on peeled surfaces clearly reveal that the peeling occurs cohesively inside polyimide. This implies a degradation of polyimide structure due to oxygen diffusion through interface between Ni and polyimide, which is also closely related to the decrease in the interfacial adhesion energy due to thermal treatment in ambient conditions.

This research aimed to establish the basic elements of social life and provided initial information to be of help to sports activity participation program by recognizing the necessity of sports activity participation, and at the same time, by using sports

This study provides a national examination on youths' 'understanding' of irradiated food. The 1,200 subjects of the survey were randomly sampled from male and female students throughout the nation, between grades five and eleven. The survey was conducted toward these samples in November 2000. The number of respondents with exposure to irradiated food was so small, amounting to only 4.0 percent of the whole sample. The core concept used in this study is 'impression'. An impression is information about a specific subject, which carries significance to an individual. The results show that the higher the grade was, the more value the contents of impression contained. Furthermore, impressions concerning atomic or nuclear energy, and radioactivity increased greatly among students in middle school and above. Providing information of effects and advantages of irradiated food was focused to increase positive impressions and decrease the negative ones more greatly than providing simple factual information. Youths showed less value-centered impressions of irradiated food and more impressions centered on fragmented facts than adults. Respondents previously exposed irradiated food were shown to acquire the most of their information from the television and newspaper media. Among six information sources presented in the survey, youths pointed out 'science and technology research institutes' as the most credible. International organizations and environmental/ consumer organizations were evaluated as having relatively high credibility. Providing simple factual information of irradiated food did not seem to bring about any difference to the intention of purchasing irradiated food. On the other hand, respondents provided with effects-included information showed an increase in such intention. Our research results of the youth show a notable difference with that of the adults. Thus, programs and strategies to enhance youths' understanding should differ from those concerning adults.