• 제목/요약/키워드: Environmental issue

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플립 칩 전자 패키지의 피로 균열이 미치는 열적 기계적 거동 분석 (Effect analysis of thermal-mechanical behavior on fatigue crack of flip-chip electronic package)

  • 박진형;이순복
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회A
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    • pp.1673-1678
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    • 2007
  • The use of flip-chip type electronic package offers numerous advantages such as reduced thickness, improved environmental compatibility, and downed cost. Despite numerous benefits, flip-chip type packages bare several reliability problems. The most critical issue among them is their electrical performance deterioration upon consecutive thermal cycles attributed to gradual delamination growth through chip and adhesive film interface induced by CTE mismatch driven shear and peel stresses. The electronic package in use is heated continuously by itself. When the crack at a weak site of the electronic package occurs, thermal deformationon the chip side is changed. Therefore, we can measure these micro deformations by using Moire interferometry and find out the crack length.

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One Health Perspectives on Emerging Public Health Threats

  • Ryu, Sukhyun;Kim, Bryan Inho;Lim, Jun-Sik;Tan, Cheng Siang;Chun, Byung Chul
    • Journal of Preventive Medicine and Public Health
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    • 제50권6호
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    • pp.411-414
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    • 2017
  • Antimicrobial resistance and emerging infectious diseases, including avian influenza, Ebola virus disease, and Zika virus disease have significantly affected humankind in recent years. In the premodern era, no distinction was made between animal and human medicine. However, as medical science developed, the gap between human and animal science grew deeper. Cooperation among human, animal, and environmental sciences to combat emerging public health threats has become an important issue under the One Health Initiative. Herein, we presented the history of One Health, reviewed current public health threats, and suggested opportunities for the field of public health through better understanding of the One Health paradigm.

International Harmonization of Accreditation of Toxicologists

  • Satoh, Tetsuo
    • Toxicological Research
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    • 제17권
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    • pp.189-191
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    • 2001
  • In the past, IUTOX engaged in dialogue with various international toxicology organizations to address this important issue. IUTOX Executive Committee engaged in activities that support accreditation and/or registration of toxicologists around the world. As a result of discussions held during the IUTOX-sponsored workshop at the 2000 Annual Meeting of the SOT in Philadelphia, it was decided to create an international forum, the "International Assembly for the Recognition of Toxicologists"(IART). The mission of IART was defined as threefold: 1) to establish a forum for development of criteria for recognizing qualified experts in toxicology; 2) to assist "recognizing organizations" in establishing these criteria; and 3) to promote identification and training needs to enhance expertise in toxicology. The membership of IART is open to all organizations (e.g., registries, boards, academies, etc.) whose purpose is the recognition of expertise in toxicology.rtise in toxicology.

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Mitochondria in Cancer Energy Metabolism: Culprits or Bystanders?

  • Kim, Aekyong
    • Toxicological Research
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    • 제31권4호
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    • pp.323-330
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    • 2015
  • Cancer is a disease characterized by uncontrolled growth. Metabolic demands to sustain rapid proliferation must be compelling since aerobic glycolysis is the first as well as the most commonly shared characteristic of cancer. During the last decade, the significance of metabolic reprogramming of cancer has been at the center of attention. Nonetheless, despite all the knowledge gained on cancer biology, the field is not able to reach agreement on the issue of mitochondria: Are damaged mitochondria the cause for aerobic glycolysis in cancer? Warburg proposed the damaged mitochondria theory over 80 years ago; the field has been testing the theory equally long. In this review, we will discuss alterations in metabolic fluxes of cancer cells, and provide an opinion on the damaged mitochondria theory.

비모수 지역난방 수요예측모형 (A Nonparametric Prediction Model of District Heating Demand)

  • 박주헌
    • 자원ㆍ환경경제연구
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    • 제11권3호
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    • pp.447-463
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    • 2002
  • The heat demand prediction is an essential issue in management of district heating system. Without an accurate prediction through the lead-time period, it might be impossible to make a rational decision on many issues such as heat production scheduling and heat exchange among the plants which are very critical for the district heating company. The heat demand varies with the temperature as well as the time nonlinearly. And the parametric specification of the heat demand model would cause a misspecification bias in prediction. A nonparametric model for the short-term heat demand prediction has been developed as an alternative to avoiding the misspecification error and tested with the actual data. The prediction errors are reasonably small enough to use the model to predict a few hour ahead heat demand.

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Measurement of UV radiation of LED lighting

  • Ku, Seong-Mo;Im, Jong-Min;Yi, Chin-Woo
    • 조명전기설비학회논문지
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    • 제25권3호
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    • pp.7-14
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    • 2011
  • Many countries and researchers in the lighting field have focused on the LED light source as a solution to energy savings and environmental pollution. The LED light source consumes less power, has a long life and is highly economical. It is vibration and shock-resistant, and environment friendly as well. But LED lighting has some problems. In particular, the photobiological safety of LED light sources is emerging as an issue. Ultraviolet radiation from the LED light source emitted directly to the human body over a long period of time is harmful. In this paper, UV radiation from white LED was measured. Finally, the LED light source emits UV radiation, but it is relatively small when compared to others.

전리수를 이용한 반도체 세정 공정 (Electrolyzed Water Cleaning for Semiconductor Manufacturing)

  • 류근걸;김우혁;이윤배;이종권
    • 반도체디스플레이기술학회지
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    • 제2권3호
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    • pp.1-6
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    • 2003
  • In the rapid changes of the semiconductor manufacturing technologies for early 21st century, it may be safely said that a kernel of terms is the size increase of Si wafer and the size decrease of semiconductor devices. As the size of Si wafers increases and semiconductor device is miniaturized, the units of cleaning processes increase. A present cleaning technology is based upon RCA cleaning which consumes vast chemicals and ultra pure water (UPW) and is the high temperature process. Therefore, this technology gives rise to environmental issue. To resolve this matter, candidates of advanced cleaning processes have been studied. One of them is to apply the electrolyzed water. In this work, electrolyzed water cleaning was compared with various chemical cleaning, using Si wafer surfaces by changing cleaning temperature and cleaning time, and especially, concentrating upon the contact angle. It was observed that contact angle on surface treated with Electrolyzed water cleaning was $4.4^{\circ}$ without RCA cleaning. Amine series additive of high pKa (negative logarithm of the acidity constant) was used to observe the property changes of cathode water.

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기후변화의 쟁점과 물 (Current Issues on Climate Change and Water)

  • 윤주환
    • 한국물환경학회지
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    • 제25권5호
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    • pp.641-650
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    • 2009
  • The IPCC's standing on the anthropogenic warming is discussed in this article. The differences between the climate alarmist and skeptics have been addressed in terms of scientific and policy stand point of view. The political and economical significances of climate change have been discussed, too. Although atmospheric temperature and rainfall precipitation are two most important factors in the climate change, most of the recent attentions have drawn on mainly temperature and $CO_2$ issue. In spite of argues on the uncertainty in anthropogenic warming related to $CO_2$, the inevitable climate change should correspondingly change the humanity in near feature.

토양내 탄화수소계 화합물의 농도측정 기법에 대한 TDR(Time Domain Reflectometry)적용 가능성 연구

  • 박민수;김동주
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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    • pp.201-205
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    • 1998
  • Leakage of hydrocarbon compound from underground storage tank has been a significant issue to the hazard of environmental contaminants. It is therefore necessary to develop the measurement technique of hydrocarbon compound concentration. In this study, the possibility of TDR application to measure concentration of hydrocarbon compound, especially diesel, in a sandy soil was investigated. Experiments were conducted in two different conditions. The first one was to measure the resistances of the soil columns packed according to the various ratios of tab water and diesel content in the total voids. The other was to measure the resistance of the soil under the flow condition where diesel oil was allowed to infiltrate into the KCl-saturated soil column. The experimental results showed that there exists a significant relationship between oil% and TDR-measured resistance. This suggests that TDR can be an effective device to measure the concentration of hydrocarbon compound in a soil.

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산림생태계 관리: 개념, 원칙 및 적용방법을 중심으로 (Forest Ecosystem Management: Concepts, Principles and Applications)

  • 손요환;김진수
    • The Korean Journal of Ecology
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    • 제20권3호
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    • pp.201-216
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    • 1997
  • Forest managers are increasingly being challenged to produce goods and services to society while managing for ecosystem sustainability. Forest ecosystem management is an emerging philosophy to achieve these objectives. We synthesized some basic concepts of forest ecosystem, sustainability in forests and forest ecosystem management, and described the importances of long-term ecological studies. Also we presented few relatively simple principles of forest ecosystem management, strategies, and case studies for integrating forest ecosystem management principles into the forest management planning process. It was emphasizd that in forest ecosystem management process, society, land managers, forest managers, and scientists be entered into a partnership to reshape management goals, redefine objectives, and redirect management actions in response to changing socioeconomic information and evolving bioogical, physical, chemical, and environmental conditions. Agreement or disagreement with our synthesis and opinions on forest ecosystem management is out of the primary objective of this paper, which is to stimulate new and creative approaches to forest ecosystem management as an emerging issue in forestry.

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