This paper describes the surface modification effect of a Ti substrate for improved dispersibility of the cat-alytic metal. Etching of a pure titanium substrate was conducted in 50% H₂SO₄, 50˚C for 1h-12h to observe the sur-face roughness as a function of the etching time. At 1h, the grain boundaries were obvious and the crystal grains weredistinguishable. The grain surface showed micro-porosities owing to the formation of micro-pits less than 1 µm in diam-eter. The depths of the grain boundary and micro-pits appear to increase with etching time. After synthesizing the cat-alytic metal and growing the carbon nano tube (CNT) on Ti substrate with varying surface roughness, the distributiontrends of the catalytic metal and grown CNT on Ti substrate are discussed from a micro-structural perspective.

부산, 경남 지역의 8개 친환경농산물인증 지역에서 카드뮴, 구리, 비소, 수은, 납, 6가크롬, 아연, 니켈 등 8개 중금속의 토양 함량을 조사하였다. 카드뮴은 그 햠량의 순으로 보면 산청, 하동, 사천, 부산순으로 함량이 높았으며, 구리는 김해, 사천, 부산, 고성 순으로, 비소는 사천, 부산, 김해, 고성 순으로, 수은은 고성, 사천, 부산, 김해 순으로, 납은 김해, 사천, 고성, 부산 순으로, 6가크롬은 김해, 부산, 하동, 산청 순으로, 아연은 김해, 부산, 사천, 함양 순으로, 니켈은 사천, 하동, 고성, 산청 순으로 각각 함양이 많았다. 전체적인 함량을 보았을 경우 김해, 사천, 부산 등 낙동강 주변의 평야지대에서 높은 수치를 보였다. 한편 하동, 진주 산청 등 중산간지에서는 전체 중금속 함량이 대체로 낮았다.

In this study, the microstructure and valuable metals dissolution properties of PDP waste panel powders were investigated as a function of milling parameters such as ball diameter size, milling time, and rotational speed during high-energy milling process. The complete refinement of powder could achieved at the ball diameter size of 5 mm due to sufficient impact energy and the number of collisions. With increasing milling time, the average particle size was rapidly decreased until the first 30 seconds, then decreased gradually about at 3 minutes and finally, increased with presence of agglomerated particles of at 5 minutes. Although there was no significant difference on the size of the particle according to the rotational speed from 900 to 1,100 rpm, the total valuable metals dissolution amount was most excellent at 1,100 rpm. As a result, the best milling conditions for maximum dissolving amount of valuable metals (Mg: 375 ppm, Ag 135 ppm, In: 17 ppm) in this research were achieved with 5 mm of ball diameter size, 3min of milling time, and 1,100 rpm of rotational speed.

In real world applications, the response of structures may be dependent on the rate of loading and thus can be affected by transient loading, especially when the rate of loading is significant. In such situations, the rate of loading may become a major issue to understand structures during earthquake excitation or under blast or high velocity impact. In some cases, the rate effect on structures under strong earthquake excitation cannot be ignored when attempting to understand inelastic behavior of structures. M any researchers developed the constitutive theories in cyclic plasticity and viscoplasticity. In this study, numerical simulation by cyclic visocoplasticity models is introduced and analyzed. Finally, the analytical results are compared with experimental results as a means to evaluate and verify the model.

본 연구는 인쇄회로기판(PCB) 제조 시 에칭공정에서 발생되는 구리이온(Cu+2)을 고농도로 함유한 황산 폐에칭액을 NF 막분리법을 사용하여 에칭액 회수와 구리이온 처리를 효율적으로 수행하기 위한 NF 막여과 공정의 운전 조건을 설정하기 위한 기본 자료를 확보하는데 있다. 이를 위해 미국 Koch사의 SelRO MPS-34 4040 NF 막을 대상으로 구리이온을 고농도(5~25 g/L)로 함유한 모의 황산 폐에칭액의 회분식(dead-end) 나노여과 실험을 수행하여 투과 플럭스와 구리이온의 총괄 배제도를 측정하였다. 이 결과 황산용액에의 막 보관기간이 길수록, 황산용액의 pH가 낮을수록 황산에 의한 NF 막의 손상이 더 크게 발생하여 순수 투과 플러스가 증가하였다. 황산 폐에칭액의 투과 플럭스는 황산용액 내 구리이온의 농도가 증가할수록 막 표면에의 구리이온 농축(농도분극)의 증가에 따라 감소하였으며, 구리이온의 배제도는 구리이온의 농도가 높을수록, pH가 낮을수록, 황산용액 내의 막 보관기간이 길수록 낮아져 초기 37%에서 최소 15% 수준으로까지 감소하였다.

This study was carried out as a survey on the level of lead (Pb), cadmium (Cd), arsenic (As) and mercury (Hg) in 5 items of agricultural products (lettuce, pumpkin, head lettuce, cabbage and crown daisy) for which safety guidelines are not yet established in Korea. The 407 samples were collected from local markets in 9 regional places and the levels of metals were measured by ICP-MS and mercury analyzer. The average levels of Pb, Cd, As and Hg were 0.026, 0.018 ,0.008 and 0.003 mg/kg for lettuce, 0.002, 0.001, 0.001 and 0.0006 mg/kg for pumpkin, 0.002, 0.005, 0.001 and 0.0005 mg/kg for head lettuce, 0.001, 0.002, 0.0002 and 0.0006 mg/kg for cabbage and 0.022, 0.014, 0.006 and 0.004 mg/kg for crown daisy. For risk assessment, the daily dietary exposures of Pb, Cd and Hg by intake of these agricultural products were calculated and compared with PTWI (provisional tolerable weekly intake) established by JECFA. The daily dietary exposure of heavy metals by intake of these agricultural products were 0.13, 0.56 and 0.09% of PTWI, respectively. These monitoring results will be utilized as fundamental data for the establishment of Korean standards of Pb, Cd, As and Hg in 5 items of agricultural products and valuable source for DB construction for science-based safety control of heavy metals in foods including agricultural products.

The objective of this study is investigation of contamination levels and assessment of health risk effects of heavy metals in herbal pills. 31 Items and 93 samples were obtained for this investigation from major herbal medicine producing areas, herbal markets and on-line supermarkets from Jan to Jun in 2010. Inductively coupled plasma mass spectrometer method was conducted for the quantitative analysis of Pb, Cd and As. In addition, the mercury analyzer system was conducted for that of Hg without sample digestion. The average contents of heavy metals in samples were as follows : 0.87 mg/kg for Pb, 0.08 mg/kg for Cd, 2.87 mg/kg for As and 0.16 mg/kg for Hg, respectively. In addition, the average contents of heavy metals in different parts of plants, including cortex, fructus, herba, radix, seed, algae and others were 0.63 mg/kg, 3.94 mg/kg, 1.42 mg/kg, 1.05 mg/kg, 0.16 mg/kg, 22.31 mg/kg and 10.17 mg/kg, respectively. After the estimations of dietary exposure, the acceptable daily intake (ADI), the average daily dose (ADD), the provisional tolerable weekly intake (PTWI) and the relative hazard of heavy metals were evaluated. As the results, the relative hazards compared to PTWI in samples were below the recommended standard of JECFA as Pb 3.1%, Cd 0.9%, Hg 0.5%. Cancer risks through slope factor (SF) by Ministry of Environment Republic Korea and Environmental Protection Agency was 4.24 × 10−7 for Pb and 3.38 × 10−4 for As (assuming that the total arsenic content was equal to the inorganic arsenic). Based on our results, possible Pb-induced cancer risks in herbal pills according to parts used including cortex, fructus, herba, radix, seed, algae and others were 1.95 × 10−7, 1.45 × 10−6, 2.14 × 10−7, 6.27 × 10−7, 1.99 × 10−8, 3.61 × 10−7 and 9.64 × 10−8, respectively. Possible As-induced cancer risks in herbal pills by parts used including cortex, fructus, herba, radix, seed, algae and others were 1.54 × 10−5, 7.24 × 10−5, 1.23 × 10−4, 2.02 × 10−5, 3.25 × 10−6, 2.18 × 10−3 and 5.67 × 10−6 respectively. Taken together, these results indicate that the majority of samples except for some samples with relative high contents of heavy metals were safe.

To evaluate the biological response of sea squirt Halocynthia roretzi with different body size to heavy metals and its suitability for ecotoxicity assays, the effects of Cr, Cu and Zn on its clearance and oxygen consumption rates were investigated. Clearance and oxygen consumption rates of H. roretzi with various body sizes were calculated at different metal concentrations. Both clearance and oxygen consumption rate were negatively correlated with body sizes. Clearance rate of H. roretzi decreased gradually with increasing concentration of heavy metal, the decreasing rate was in an order of Cr¤Cu¤Zn. The oxygen consumption rate first increased at low metal concentration (below 100 μg L-1) and then decreased rapidly with increasing metal concentrations. The decreasing rate was in an order of Cu¤Cr=Zn. There was a trend that the clearance rate and oxygen consumption rate decreased drastically under a concentration of 400 μg L-1, and then decreased smoothly when the metal ion concentration increased continually. So the oxygen consumption and clearance rate at a concentration of 400 μg L-1 Cu could be thought as a suitable biological tool for exotoxicology analysis.

지구적으로 양서류가 감소하고 있다. 오래전부터 중금속은 양서류 군집 감소의 원인 중 한가지로 지목받고 있다. 수정 후 변태에 이르는 생활사를 수중에서 진행하는 양서류는 수환경 내의 오염물질에 1차적으로 노출되며 독성효과에 대한 감수성이 높아 수환경의 오염에 특히 취약하다. 양서류는 수서생태계의 건강도 지표로서 유용할 뿐 아니라 분자 및 개체수준의 다양한 생체지표를 이용한 다양한 환경오염물질의 독성평가 모델로서도 유용하다. 양서류에서 얻어진 독성자료는 수환경 오염물질의 관리와 안전관리기준으로 사용될 수 있다. 본 논문에 서는 기존에 보고된 중금속이 양서류의 다양한 독성종말점에 미치는 영향들에 대해 검토하고 분석하였다.

In this study, voltammetry system for realizing high sensitivity nano-labeled sensor of detecting heavy metals was designed, and optimal system operating conditions were determined. High precision digital to analog converter (DAC) circuit was designed to control applied unit voltage at working electrode and analog to digital converter (ADC) circuit was designed to measure the current range of at counter electrode. Main control unit (MCU) circuit for controlling voltammetry system with 150 MHz clock speed, main memory circuit for the mathematical operation processing of the measured current value and independent power circuit for analog/digital circuit parts to reduce various noise were designed. From result of voltammetry system operation, oxidation current peaks which are proportional to the concentrations of Zn, Cd and Pb ions were found at each oxidation potential with high precision.

Self-piercing riveting(SPR) is a sheet joining method that can be used for materials which are difficult or unsuitable to weld, such as aluminum alloy and different steel sheet metals. No pre-drilled hole is needed for SPR; the rivets are pushed directly into the sheets clamped together between a blank holder and a die in a press tool. In this paper, self-piercing rivet and anvil were designed for four joining conditions with dissimilar sheet metals. SPR was simulated by using commercial FEM code DEFORM-2D. In simulation of SPR process, various strengths of self-piercing rivet were considered. The mechanical properties could be determined by tensile test for quenched rivets and sheet metals. The designs of rivet and anvil were modified by comparisons of simulated results.

본 연구는 충남 청양의 폐광산 지역과 인근 대조구에 분포하는 Artenmisia princeps var. orientalis(쑥), Equisetum arvense(쇠뜨기)를 이용하여 식물체 내 중금속 함량이 미생물의 활성에 미치는 영향에 대해 알아보았다. 낙엽 회수시 측정한 호흡량은 처음 회수시 가장 높은 값을 나타내었으며, 시간이 지날수록 발생량은 감소하는 경향을 나타내었으며, 중금속의 함량이 높은 낙엽에서 미생물의 호흡량이 낮았으며 대조구에서 채집하여 대조구에서 분해시킨 쑥과 쇠뜨기에서 가장 빠른 분해를 보인 것으로 나타났다. 쑥과 쇠뜨기 모두 중금속 함량이 적은 낙엽에서 높은 미생물량을 나타내었다. 낙엽의 분해율과 누적호흡량, 낙엽의 분해율과 미생물량사이에는 각각 뚜렷한 양의 상관관계를 나타내었다. 따라서 본 연구결과 식물체 내의 중금속이 분해과정에 관여하는 미생물의 생장과 활성에 부정적인 영향을 미친 결과라 할 수 있다.

본 연구에서는 폐금속 광산 주변 비소와 중금속으로 오염된 논토양을 효과적으로 복원하기 위한 안정화 제로써 석회석과 제강슬래그의 처리효과와 그 적용성을 검토하기 위해 담수답의 환원 환경을 적용한 컬럼 실험을 실시하였다. 실험결과 담수된 논토양의 환원 환경에서는 철과 망간 성분이 환원되어 급격하게 용출되는 시점에 중금속 성분도 급격하게 용출되는 경향이 나타났으며, 대조구(무처리)의 경우 침출수에서 오염기준을 초과한 시료가 나타났다. 그러나 석회석 5%와 제강슬래그 5%로 각각 처리한 토양은 모두 오염기준 이하로 대조구보다 중금속 농도가 매우 낮게 검출되었다. 석회석과 제강슬래그 모두 담수답의 환원 환경에서 좋은 처리효과를 나타내어 효과적인 안정화제로 판단되었으며, 특히 제강슬래그는 담수답 환 경에서 지속적으로 증가하는 비소 성분에 대해서 좋은 처리효과를 나타내었다.

2010년 1월부터 1011년 9월에 걸쳐 조선철강 업체가 밀집하고 있는 목포내항, 광양만 그리고 비교구인 신안증도 해역 을 중심으로 저층퇴적물 내의 중금속 함량을 조사하여 지점별 해역별 오염도를 비교 분석하였다. 목포내항에서는 비교구 지점보다 높게 분포하고 있었고 특히, 선박수리 해체 업체의 플로팅도크 주변해역에서 높게 분포하고 있었다. EPA 기준치와 ERL의 기준치와 비교해서는 카드뮴과 구리, 크롬은 높았고 납은 3개 정점이 초과 하였으나 그 외 정점에서는 기준치 이하 농도였다. 아연은 전 정점에서 기준치보다 낮게 분포하였다. 앞으로 광양만과 신안군 증도 해역의 퇴적물내의 중금속 함량과 비교하고 부화지수와 농집지수 등을 통해 퇴적물의 중금속의 오염도를 평가할 계획이다

Proteomics may help to detect subtle pollution-related changes, such as responses to mixture pollution at low concentrations, where clear signs of toxicity are absent. Also proteomics provide potential in the discovery of new sensitive biomarkers for environmental pollution. We utilized SELDI-TOF MS (surface enhanced laser desorption. / ionization time-of-flight mass spectrometry) to analyze the proteomic profile of Heterocypris incongruens exposed to several heavy metals (lead, mercury, copper, cadmium and chromium) and pesticides (emamectin benzoate, endosulfan, cypermethrin, mancozeb and paraquat dichloride). Several highly significant biomarkers were selected to make a model of classification analysis. data sets obtained from H. incongruens exposed to pollutants were investigated for differential protein expression by SELDI-TOF MS and decision tree classification. Decision tree model was developed with training set, and then validated with test set from profiling data of H. incongruens. Machine learning techniques provide a promising approach to process the information from mass spectrometry data. Even thought the identification of protein would be ideal, class discrimination does not need it. In the future, this decision tree model would be validated with various levels of pollutants to apply field samples.

본 연구는 사문암 토양의 화학적 성질과 토양미생물량 및 토양효소 등 토양의 생물학적 활성을 대조구의 비사문암 토양과 비교하고, 사문암과 비사문암에서 공통으로 서식하는 새(Arundinella hirta)와 억새(Miscanthus sinensis var. purpurascens)의 낙엽이 입지가 다른 사문암지역과 비사문암 지역에서 분해될 때 분해율의 차이가 어떻게 유발되는지 9개월 동안 야외에서 교차 실험하였다. 사문암 토양은 비사문암 토양에 비하여 높은 pH, 낮은 dehydrogenase 와 urease활성을 나타내었으며 alkaliphosphatase의 활성은 높았다. 두 토양에서 microbial biomass-C와 N의 차이는 유의하지 않았으나 사문암 토양에서 microbial biomass-N함량이 더 높게 나타나 비사문암 토양에서 보다 낮은 토양의 C/N을 나타내는 원인이 되었다. 사문암지역에서의 낙엽분해실험에서는 사문암지역에서 획득한 새와 억새 낙엽이 각각 39.8%, 38.5%의 중량감소를 보였으며, 비사문암 토양에서 획득한 낙엽은 각각 41.1%, 41.7%의 중량감소를 나타내었다. 비사문암지역에서의 낙엽분해실험에서는 사문암낙엽이 46.8%, 42.2% 그리고 비사문암낙엽은 44.8%, 37.4%의 중량감소를 각각 보였다. 이러한 결과는 중금속을 포함하는 토양의 영향보다는 낙엽의 질적 차이가 분해율에 더 큰 영향을 미쳤음을 나타내준다. 일반적으로 낮은 C/N을 갖는 낙엽이 더 빨리 분해된다는 결과와는 달리 낮은 C/N을 갖는 사문암낙엽의 분해가 느린 것은 낙엽에 포함된 중금속의 저해가 낙엽의 C/N이나 lignin/N과 같은 낙엽의 질적 차이에서 유발되는 낙엽분해의 저해보다 큰 영양을 미친다는 결과를 보여주었다. 또한 낙엽분해가 진행되는 동안 낙엽내의 Cr, Ni과 Mg, Fe의 농도는 점차 증가하였으며 이러한 경향은 사문암지역에서 현저하였다.

The investigation was initiated with data from 27 abandoned mines along with 12 locations in Kyongbuk abandoned mines. The analyses for soil pollution by heavy metal pollutants were conducted by using correlation analysis, cluster analysis, and principal component analysis. The correlation analysis indicated that Ni and pH were highly correlated compared to those of other heavy metal ions. The principal component analyses showed that the heavy metal ions might be classified into two catagories, such as antropogenic and lithogenic components. The cluster analysis was also clearly divided by two groups. The respective two groups might be Pb-Zn-Cd-Cu and As-Hg-Ni.