• Title, Summary, Keyword: PCBs

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The characteristics of bismuth magnesium niobate multi layers deposited by sputtering at room temperature for appling to embedded capacitor (임베디드 커패시터로의 응용을 위해 상온에서 RF 스퍼터링법에 의한 증착된 bismuth magnesium niobate 다층 박막의 특성평가)

  • Ahn, Jun-Ku;Cho, Hyun-Jin;Ryu, Taek-Hee;Park, Kyung-Woo;Cuong, Nguyen Duy;Hur, Sung-Gi;Seong, Nak-Jin;Yoon, Soon-Gil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.62-62
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    • 2008
  • As micro-system move toward higher speed and miniaturization, requirements for embedding the passive components into printed circuit boards (PCBs) grow consistently. They should be fabricated in smaller size with maintaining and even improving the overall performance. Miniaturization potential steps from the replacement of surface-mount components and the subsequent reduction of the required wiring-board real estate. Among the embedded passive components, capacitors are most widely studied because they are the major components in terms of size and number. Embedding of passive components such as capacitors into polymer-based PCB is becoming an important strategy for electronics miniaturization, device reliability, and manufacturing cost reduction Now days, the dielectric films deposited directly on the polymer substrate are also studied widely. The processing temperature below $200^{\circ}C$ is required for polymer substrates. For a low temperature deposition, bismuth-based pyrochlore materials are known as promising candidate for capacitor $B_2Mg_{2/3}Nb_{4/3}O_7$ ($B_2MN$) multi layers were deposited on Pt/$TiO_2/SiO_2$/Si substrates by radio frequency magnetron sputtering system at room temperature. The physical and structural properties of them are investigated by SEM, AFM, TEM, XPS. The dielectric properties of MIM structured capacitors were evaluated by impedance analyzer (Agilent HP4194A). The leakage current characteristics of MIM structured capacitor were measured by semiconductor parameter analysis (Agilent HP4145B). 200 nm-thick $B_2MN$ muti layer were deposited at room temperature had capacitance density about $1{\mu}F/cm^2$ at 100kHz, dissipation factor of < 1% and dielectric constant of > 100 at 100kHz.

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Stray Light Analysis of a Compact Imaging Spectrometer for a Microsatellite STSAT-3 (과학기술위성3호 부탑재체 소형영상분광기 미광 해석)

  • Lee, Jin Ah;Lee, Jun Ho
    • Korean Journal of Optics and Photonics
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    • v.23 no.4
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    • pp.167-171
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    • 2012
  • This paper reports on the stray light analysis results of a compact imaging spectrometer (COMIS) for a microsatellite STSAT-3. COMIS images Earth's surface and atmosphere with ground sampling distances of 27 m at the 18~62 spectral bands (0.4 ~ 1.05 ${\mu}m$) for the nadir looking at an altitude of 700 km. COMIS has an imaging telescope and an imaging spectrometer box into which three electronics PCBs are embedded. The telescope images a $27m{\times}28km$ area of Earth surface onto a slit of dimensions $11.8{\mu}m{\times}12.1mm$. This corresponds to a ground sampling distance of 27 m and a swath width of 28 km for nadir looking posture at an altitude of 700 km. Then the optics relays and disperses the slit image onto the detector thereby producing a monochrome image of the entrance slit formed on each row of detector elements. The spectrum of each point in the row is imaged along a detector column. The optical mounts and housing structures are designed in order to prevent stray light from arriving onto the image and so deteriorating the signal to noise ratio (SNR). The stray light analysis, performed by a non-sequential ray tracing software (LightTools) with three dimensional housing and lens modeling, confirms that the ghost and stray light arriving at the detector plane has the relative intensity of ${\sim}10^{-5}$ and furthermore it locates outside the concerned image size i.e. the field of view of the optics.

Assessment of Persistent Organic and Heavy Metal Contamination in Busan Coast: Application of Sediment Quality Index (부산 연안해역의 잔류성 유기오염물질과 중금속 오염평가: 퇴적물 오염지수 적용)

  • Han, Gi Myung;Hong, Sang Hee;Shim, Won Joon;Ra, Kong Tae;Kim, Kyung Tae;Ha, Sung Yong;Jang, Mi;Kim, Gi Beum
    • Ocean and Polar Research
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    • v.38 no.3
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    • pp.171-184
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    • 2016
  • In order to assess the level of contamination and identify the priority contaminants in the Busan coast, intensive sediment sampling was conducted and persistent organic pollutants and heavy metals were analyzed. The Sediment Quality Index (SQI) was derived based on the contaminant data by comparing with Sediment Quality Guidelines (SQGs) established in Korea, Canada, and Australia/New Zealand. Toxic contaminants were found to be widely distributed across the coast. Among organic contaminants, PAHs showed the highest concentration, followed by butyltins, nonylphenols, PBDEs, DDTs, PCBs, HCHs and CHLs. Heavy metals were also abundantly detected with the highest concentration of Zn followed by Cu > Cr > Pb > Ni > As > Cd > Hg. Compared to organic contaminants, most heavy metals, except for Cu and Hg, were homogeneously distributed along the coast in a good relationship with total organic carbon of sediment particles. In general, the concentrations of organic compounds and heavy metals were highest at the inner part of harbor areas with a tendency to decline from inside areas to the outside, indicating the high loading of pollutants from harbors. A high exceedance for low-SQGs and high-SQGs was found for TBT, p'-DDT, p,p'-DDD, Cu and Zn. The SQI scores calculated from low-SQGs and high-SQGs were in the range of 18-100 and 54-100, respectively. The inner part of Busan Harbor, Dadaepo Harbor, and Gamcheon Harbor were observed as being regions of concern. Overall, TBT, Cu, and p,p'-DDT were the chemicals most frequently exceeding SQGs and influencing SQI scores.

Experimental and Numerical Analysis of Microvia Reliability for SLP (Substrate Like PCB) (실험 및 수치해석을 이용한 SLP (Substrate Like PCB) 기술에서의 마이크로 비아 신뢰성 연구)

  • Cho, Youngmin;Choa, Sung-Hoon
    • Journal of the Microelectronics and Packaging Society
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    • v.27 no.1
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    • pp.45-54
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    • 2020
  • Recently, market demands of miniaturization, high interconnection density, and fine pitch of PCBs continuously keep increasing. Therefore, SLP (substrate like PCB) technology using a modified semi additive process (MSAP) has attracted great attention. In particular, SLP technology is essential for the development of high-capacity batteries and 5G technology for smartphones. In this study, the reliability of the microvia of hybrid SLP, which is made of conventional HDI (high density interconnect) and MSAP technologies, was investigated by experimental and numerical analysis. Through thermal cycling reliability test using IST (interconnect stress test) and finite element numerical analysis, the effects of various parameters such as prepreg properties, thickness, number of layers, microvia size, and misalignment on microvia reliability were investigated for optimal design of SLP. As thermal expansion coefficient (CTE) of prepreg decreased, the reliability of microvia increased. The thinner the prepreg thickness, the higher the reliability. Increasing the size of the microvia hole and the pad will alleviate stress and improve reliability. On the other hand, as the number of prepreg layers increased, the reliability of microvia decreased. Also, the larger the misalignment, the lower the reliability. In particular, among these parameters, CTE of prepreg material has the greatest impact on the microvia reliability. The results of numerical stress analysis were in good agreement with the experimental results. As the stress of the microvia decreased, the reliability of the microvia increased. These experimental and numerical results will provide a useful guideline for design and fabrication of SLP substrate.

Estimation of fire Experiment Prediction by Utility Tunnels Fire Experiment and Simulation (지하공동구 화재 실험 및 시뮬레이션에 의한 화재 설칠 예측 평가)

  • 윤명오;고재선;박형주;박성은
    • Fire Science and Engineering
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    • v.15 no.1
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    • pp.23-33
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    • 2001
  • The utility tunnels are the important facility as a mainstay of country because of the latest communication developments. However, the utilities tunnel is difficult to deal with in case of a fire accident. When a cable burns, the black smoke containing poisonous gas will be reduced. This black smoke goes into the tunnel, and makes it difficult to extinguish the fire. Therefore, when there was a fire in the utility tunnel, the central nerves of the country had been paralyzed, such as property damage, communication interruption, in addition to inconvenience for people. This paper is based on the fire occurred in the past, and reenacting the fire by making the real utilities tunnel model. The aim of this paper is the scientific analysis of the character image of the fire, and the verification of each fire protection system whether it works well after process of setting up a fire protection system in the utilities tunnel at a constant temperature. The fire experiment was equipped with the linear heat detector, the fire door, the connection water spray system and the ventilation system in the utilities tunnel. Fixed portion of an electric power supply cable was coated with a fire retardant coating, and a heating tube was covered with a fireproof. The result showed that the highest temperature was $932^{\circ}c$ and the linear heat detector was working at the constant temperature, and it pointed at the place of the fire on the receiving board, and Fixed portion of the electric power supply cable coated with the fire retardant coating did not work as the fireproof. The heating tube was covered with the fireproof about 30 minutes.

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Development of Method for Possibility Assessment on Organic Resources for Using Raw Material of Compost (유기성자원의 퇴비원료로 활용 가능성 평가방법 개발)

  • Lim, Dong-Kyu;Lee, Seung-Hwan;Seong, Ki-Seog;So, Kyu-Ho;Shin, Jung-Du;Lee, Jeong-Taek
    • Korean Journal of Environmental Agriculture
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    • v.25 no.1
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    • pp.77-84
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    • 2006
  • This study was conducted to find a system for screening organic resources with 16 species, 62 samples which were selected to randomizing point from city, province and industrial areas in the whole country. Content of organic matters were $65.3%{\sim}98.0%$ in all samples so that they were largely over than 60%, raw material regulation of compost. Concentrations of total nitrogen and total phosphorus were $0.7{\sim}4.8%\;and\;0.8{\sim}5.0$, they could look for effect of the nitrogen and phosphorus supply as a raw material of compost. In case of 8 elements concentrations of heavy metal, they were too high to use as raw materials of compost which were over to regulation limit in Cu, Cr, Ni, and As from fiber industry, Ni from food company and leather industry, and the others are adapt to limit levels. HEM contents fro the highest to $113mg\;kg^{-1}$ from liber industry and PAHs content were the highest to $3,462ug\;kg^{-1}$ from paper-mill manufacture. Distribution of PAHs concentiations were naphthalene>phenanthrene>pyrene>fluoroanthene>acenaphthene. $Microtox{(R)}\;EC_{50}$ values for bioassay were pharmaceutical company>paper-mill manufacture>industrial area sewage sludge>fiber industry>urban sewage sludge>metropolitan sewage sludge. HEM between Zn, Cu, and Ni was significant at the 99% and between Cd was significant at the 95%, Microtox between Hg and BEM significant at the 95%.

Developing a Questionnaire to Assess Exposure to Food-Borne Hazards (식품으로 인한 유해물질 노출평가를 위한 설문지 개발)

  • Shin, Sang-Ah;Choi, Seul-Ki;Kim, Hye-Mi;Lee, Kyung-Youn;Shin, Sang-Hee;Lee, Jung-Won;Yu, Soo-Hyun;Nam, Hye-Soen;Yoon, Hae-Jung;Joung, Hyo-Jee
    • Journal of Nutrition and Health
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    • v.44 no.1
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    • pp.61-73
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    • 2011
  • The aim of this study was to develop a reliable dietary questionnaire to assess human exposure to food-borne hazards. Eleven food-borne hazards were chosen as a priority control list through a literature review and advisory committees. The 11 food-borne hazards were phthalate, aflatoxin, bisphenol A, polycyclic aromatic hydrocarbons, dioxin, polychlorinated biphenyls, mercury, lead, cadmium, arsenic, and acrylamide. The characteristics, exposure level, and paths of these hazards were reviewed, and questionnaire items were identified to assess human exposure from the literature. A questionnaire was developed for each selected food based on its characteristics. Based on the items in the individual questionnaires, a comprehensive questionnaire, which contained demographic characteristics, job information, socioeconomic factors, health related lifestyles, and dietary behaviors, was developed. A 99-item food frequency questionnaire (FFQ) to assess food-borne hazard exposure was also developed. The FFQ included frequency of food intake during the previous year, container type for purchasing and storing food, and cooking method. The questionnaire developed in this study could be applied to assess dietary factors during an exposure assessment of food-borne hazards in a large population. A validation study for the questionnaire is needed before applying it to surveys.

Prioritizing Management Ranking for Hazardous Chemicals Reflecting Aggregate Exposure (통합노출을 고려한 유해물질 관리의 우선순위 선정)

  • Jeong, Ji-Yoon;Jung, Yoo-Kyung;Hwang, Myung-Sil;Jung, Ki-Kyung;Yoon, Hae-Jung
    • Journal of Food Hygiene and Safety
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    • v.27 no.4
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    • pp.349-355
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    • 2012
  • In this study, we configured a system which ranks hazardous chemicals to determine their management priorities based on experts' opinions and the existing CRS (chemical ranking and scoring). Aggregate exposure of food, health functional food, oriental/herbal medicine and cosmetics have been taken into account to determine management priority. In this study, 25 hazardous chemicals were selected, such as cadmium, lead, mercury, and arsenic, etc. These 25 materials were ranked according to their 1) risk (exposure or hazard) indexes, 2) exposure source-based weight, and 3) public interests, which were also formed based on the existing priority ranking system. Cadmium was scored the highest (178.5) and bisphenol A the lowest (56.8). Ten materials -- cadmium, lead, mercury, arsenic, tar, acrylamide, benzopyrene, aluminium, benzene, and PAHs -- scored higher than 100. Eight materials -- aflatoxin, manganese, phthalate, chromium, nitrate/nitrite, ethylcarbamate, formaldehyde, and copper -- recorded scores in the range from 70 to 100. Also evaluated as potential risks were 7 materials; sulfur dioxide, ochratoxin, dioxins, PCBs, fumonisin, methyl mercury, and bisphenol A, and these materials were scored above 50. Then we compared risk index and correlation coefficient of total scores to confirm the validity of the total scores; we analyzed correlation coefficient of parameter and indicator. We discovered that the total score and weight, which has incorporated public interests, were high and statistically significant. In conclusion, the result of this study contributes to strengthening risk assessment and risk management of hazardous chemicals.

Study on the Screening System of Organic Resources for Agricultural Utilization (유기성 자원의 농업적 활용을 위한 선별체계 연구)

  • Lim, Dong-Kyu;Lee, Seung-Hwan;Kwon, Soon-Ik;So, Kyu-Ho;Sung, Ki-Suk;Koh, Mun-Hwan;Lee, Jeong-Taek
    • Korean Journal of Soil Science and Fertilizer
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    • v.38 no.2
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    • pp.92-100
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    • 2005
  • This study was conducted to find suitable methods for screening organic resources useful for compost. Twenty-seven industrial and domestic sludges were collected from various cities and industrial areas. Contents of organic matters in the sludges were in the range of 79.3-98.0%, and the contents were much higher than the regulation level (60%) for raw materials of compost. Contents of total nitrogen were in the range of 0.8-2.6%. Contents of Fe and Al were very high. Content of HEM was highest in textile sludge ($257mg\;kg^{-1}$) and the contents in the others were in the range of $12.6-90.3mg\;kg^{-1}$. Content of PAHs was lowest in food sludge ($739.1{\mu}g\;kg^{-1}$ and pulp-mill sludge had the highest PAHs content ($3461.8{\mu}g\;kg^{-1}$). $Microtox^{(R)}$ $EC_{50}$ values were higher in the sludges which were classified as a possible material in composting after analysis and investigation. Lettuce root elongation and $EC_{50}$ values were relatively lower in pulp-mill sludge, sewage sludge 3 (Large city), food sludge and leather sludge. Therefore, mineral nutrients, heavy metals, organic compounds (HEM, PAHs, PCBs), and bioassay ($Microtox^{(R)}$ $EC_{50}$, Relative root elongation test) are recommended to be included in the screening system of raw material of compost in addition to the current regulation with organic matter and 8 heavy metals.

Environmental Pollutants in Streams of Andong District and Insect Immune Biomarker (안동지역 하천의 환경오염물질과 곤충면역 생체지표 분석)

  • Ryoo Keon Sang;Ko Seong-Oon;Cho Sunghwan;Lee Hwasung;Kim Yonggyun
    • Korean journal of applied entomology
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    • v.44 no.2
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    • pp.97-108
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    • 2005
  • Samples of water, soil, and sediment were taken from 10 streams near Andong, Korea in May 2004. To assess the degree of environmental pollution of each stream, chemical pollutants such as total notrogen (T-N), total phosphorus (T-P), chemical oxygen demand (COD), heavy metals, organophosphorus pesticides, organochlorine pesticides, and dioxin-like PCB congeners were analyzed by standard process tests or U.S. EPA methods. In addition, biomarkers originated from insect immune systems of beet armyworm, Spodoptera exigua, were used to analysis of the environmental samples. Except Waya-chun stream showing T-N content of 9.12 mg/L, most streams were contaminated with relatively low levels of overall pollutants in terms of T-N, T-P, and COD, compared to their acceptable environmental levels designated by the Ministry of Environment. Contents of Pb and Cd in samples of each stream were much lower than environmentally permissible levels. However, several times higherconcentrations of Pb and Cd were found in locations at Mi-chun, Kilan-chun, and Hyunha-chun streams, in comparison with other streams. Diazinon, parathion, and phenthoate compounds among organophosphorus pesticides were detected as concentrations of 0.19, 0.40, and $1.13\;{\mu}g/g$, respectively, from soil sample collected in the vicinity of Mi-chun stream. On the other hand, 16 organochlorine pesticides and 12 dioxin-like PCB congeners, known as endocrine disrupting chemicals, selected in this study were not found above the limit of detection. Biomarker analyses using insect immune responses indicated that Waya-chun stream was suspected as exposure to environmental pollutants. Limitation and compensation of both environmental analysis techniques are discussed.