• E2M - 전기 전자와 첨단 소재
• /
• 제9권9호
• /
• pp.918-924
• /
• 1996

A downstream oxygen plasma is generated by capacitively coupled RF power and applied to photoresist stripping. Stripping rate (ashing rate) is measured in terms of RF power, chamber pressure, oxygen flow rate and temperature. Ashing reaction is thermally activated and depends on oxygen radical density. The ashing process is optimized to have the high ashing rate, good uniformity and minimal plasma damage using a statistical method.

• 한국산업보건학회지
• /
• 제6권2호
• /
• pp.301-312
• /
• 1996

This study was performed to search a optimal analyzing method of cadmium in whole-blood. Cadmium was determined by graphite furnace atomic absorption spectrometry(GFAAS). We investigated the effect of ashing temperature on the absorbance of cadmium in a simple dilution(ten-fold) method with triton X-100 and matrix modifier methods treated with $NH_4H_2PO_4$(1 and 3%) and $Pd(NO_3)_2$(0.00l and 0.005%) as matrix modifier. We also compared the reported reference values of standard blood with values resulted from optimal analyzing conditions of this study. In case of a simple dilution method, when ashing temperature was set at $450^{\circ}C$, the absorbance of sample and background were $0.334{\pm}0.012$ and $1.382{\pm}0.245$, respectively. Background level was higher than the value(0.8) that can be corrected by $D_2$ background correction method. As ashing temperature was rised to $500^{\circ}C$, the absorbance of sample and background were $0.178{\pm}0.008$ and $0.711{\pm}0.223$ respectively. The higher ashing temperature($450^{\circ}C-650^{\circ}C$) was, the lower the absorbance of sample was. In case of a matrix modifier method with $NH_4H_2PO_4$(1 and 3%), when ashing temperature was rised from $500^{\circ}C$ to $650^{\circ}C$, the absorbance of sample slightly changed. The absorbances of sample at $600^{\circ}C$ were $0.230{\pm}0.017$ and $0.137{\pm}0.012$, respectively. These values were larger than that of simple dilution method. But the absorbance of background was higher than the level that can be corrected by $D_2$ method. In case of a matrix modifier method with $Pd(NO_3)_2$(0.001 and 0.005%), the absorbance of sample and background were higher than those of other methods and were stable and reproducible. When ashing temperature was over $550^{\circ}C$, the absorbance of sample was significantly decreased. In case of 0.005% $Pd(NO_3)_2$ carbon residue remained in graphite tube affected the absorbance of sample and background. From these results, We propose that in case of a simple dilution(ten-fold) method with triton X-100 ashing temperature must be maintained below $400^{\circ}C$. In order to diminish the absorbance of background, the alternative method is attenuation of injection volume or multiplication of dilution ratio. We recommend $Pd(NO_3)_2$ than $NH_4H_2PO_4$ as a matrix modifier. In case of a matrix modifier method with $Pd(NO_3)_2$ ashing temperature might be maintained below $550^{\circ}C$.

• 한국산업보건학회지
• /
• 제23권4호
• /
• pp.333-340
• /
• 2013

Objectives: This study was designed to establish an accurate analytical method for asbestos in a biological sample for determining occupational asbestos-related diseases and relief of the health effects of environmental asbestos. Methods: Biological samples were obtained from lungs of rats following intratracheal instillation of asbestos(Chrysotile, anthophyllite) and were prepared according to digestion method(Wet digestion, high temperature ashing, low temperature ashing). The samples were then analyzed for asbestos fibers using a transmission electron microscope equipped with an energy dispersive X-ray spectrometer. Results: Low temperature plasma ashing removed more of the organic components and reduced fiber loss compared to the wet digestion method, making specimens so prepared more suitable for transmission electron microsocpy. Conclusions: The low temperature ashing technique is the most accurate method for analyzing asbestos in biological samples.

• 환경위생공학
• /
• 제16권1호
• /
• pp.91-101
• /
• 2001

In order to propose a optimum method increasing accuracy and reproducibility in analysis of urine lead levels, we compared matrix modifier addition method and microwave digestion method. The results were as follows ; 1. Where the concentration of $Pd(NO_3)_2$(matrix modifier) was $50mg/{\ell}$, and ashing temperature was $900^{\circ}C$, the results were optimum. In case of matrix modifier addition method, the average coefficient of variation (CV) of normal man was 24.1%, and lead worker was 7.9%. The average urine lead levels of standard were $10.42\mu{g}/{\ell}$ and $19.89\mu{g}/{\ell}$ , the accuracies compared to reference values were 97.0% and 92.6%, respectively. 2. Microwave digestion temperature($160~180^{\circ}C$), time(15~25min) and the ratio of urine/ashing acid(1:1~4:1) did not significantly affect lead absorbance and background absorbance. Therefore we set up a optimum analytical conditions as follows: temperature, $160^{\circ}C$; time, 15min; the ratio of urine/ashing acid, 4:1. after samples were digested by the above analytical conditions, lead absorbance and background absorbance was measured at $450^{\circ}C$ as ashing temperature. The average coefficient of variation (CV) of normal man was 12.4%, and lead worker was 6.2%. The average urine lead levels of standard urine were $10.66\mu{g}/{\ell}$ and $23.31\mu{g}/{\ell}$, the accuracies compared to reference values were 99.3% and 103.9%, respectively. From the results, we suggest that microwave digestion method is a more favorable method than matrix modifier addition method because of easiness to reduce organic matter, possibility to analysis at low temperature and accuracy.

• 한국재료학회지
• /
• 제20권10호
• /
• pp.550-554
• /
• 2010

This work presents a fabrication procedure to make large-area, size-tunable, periodically different shape metal arrays using nanosphere lithography (NSL) combined with ashing and annealing. A polystyrene (PS, 580 ${\mu}m$) monolayer, which was used as a mask, was obtained with a mixed solution of PS in methanol by multi-step spin coating. The mask morphology was changed by oxygen RIE (Reactive Ion Etching) ashing and temperature processing by microwave heating. The Au or Pt deposition resulted in size tunable nano patterns with different morphologies such as hole and dots. These processes allow outstanding control of the size and morphology of the particles. Various sizes of hole patterns were obtained by reducing the size of the PS sphere through the ashing process, and by increasing the size of the PS sphere through annealing treatment, which resulted in tcontrolling the size of the metallic nanoparticles from 30 nm to 230 nm.

• 반도체디스플레이기술학회지
• /
• 제16권2호
• /
• pp.55-60
• /
• 2017

The supercritical $CO_2$ (sc-$CO_2$) mixture and the sc-$CO_2$-based Photoresist(PR) stripping(SCPS) process were applied to the removal of the post etch/ash PR residue on aluminum patterned wafers and the results were observed by scanning of electron microscope(SEM). In the case of MDII wafers, the carbonized PR was able to be effectively removed without pre-stripping by oxygen plasma ashing by using sc-$CO_2$ mixture containing the optimum formulated additives at the proper pressure and temperature, and the same result was also able to be obtained in the case of HDII wafer. It was found that the efficiency of SCPS of ion implanted wafer improved as the temperature of SCPS was high, so a very large amount of MEA in the sc-$CO_2$ mixture could be reduced if the temperature could be increased at condition that a process permits, and the ion implanted photoresist(IIP) on the wafer was able to be removed completely without pre-treatment of plasma ashing by using the only 1 step SCPS process. By using SCPS process, PR polymers formed on sidewalls of metal conductive layers such as aluminum films, titanium and titanium nitride films by dry etching and ashing processes were removed effectively with the minimization of the corrosion of the metal conductive layers.

• 분석과학
• /
• 제7권4호
• /
• pp.427-434
• /
• 1994

GFAAS(graphite furnace atomic absorption spectrophotometer)를 이용하여 혈액 중 납을 분석할 때, 납은 비교적 휘발성 원소인 관계로 바탕선이 높아지므로 희화 온도를 일정 온도 이상으로 높일 수 없었다. 그래서 종래에는 매트릭스 변형제를 사용하여 희화 온도를 $700^{\circ}C$까지 올려서 희화시켜야 바탕선이 안정되었다. 본 연구에서는 광온도 및 전류 제어 장치가 부착된 기기(Shimadzu, AA-6501S)를 사용하여 온도조절을 단시간에 정확히 함으로써 매트릭스 변형제를 사용하지 않고 Triton X-100으로만 희석하여 분석해도 희화 온도 $550^{\circ}C$ 부근에서 바탕선이 안정됨을 알았다. 또한 자동 바탕 보정 장치인 $D_2$ arc형과 SR(self reversal)법을 비교해 본 결과, 같은 농도에서의 흡광도는 $D_2$ arc형이 높았으나 BGC(background correction)값은 SR법이 높음을 알았다.

• 펄프종이기술
• /
• 제31권2호
• /
• pp.77-85
• /
• 1999

A study on the thermal stability of commonly used six fillers, such as titanium dioxide, silica, ground calcium carbonate, zeolite, and, clay, showed that most fillers except titanium dioxide were strongly effected by heat treatment. Therefore, the present methods for determination of ash in paper give weight loss due to thermal decomposition of fillers. It was found that a paper ashing method at a temperature of 40$0^{\circ}C$ allows most fillers in their original and undecomposed from. Results presented in this paper also show that X-ray diffraction can be used for qualitative determination of mixed fillers and coating pigments in a paper sheet.

• 한국식품영양과학회지
• /
• 제31권2호
• /
• pp.241-245
• /
• 2002

본 연구에서는 타조 사육농장으로부터 폐기물로 나오는 타조알 껍질을 부가가치가 높은 칼슘 자원으로 활용하고자, 타조알 껍질의 회화분으로부터 젖산칼슘을 효과적으로 제조할 수 있는 최적 조건을 검토하고 이들 제품의 품질을 조사 하였다. 젖산칼슘 제조시 최적조건으로, 젖산 용액의 농도는 CaO : 젖산의 몰 비가 1 : 2.00, 젖산용액의 양은 30 mL, 반응 온도와 시간은 실온에서 15분으로 간주되었다. 젖산칼슘의 품질을 검사한 결과, 무기질 성분으로 Ca 함량은 39.70%로 타조알 껍질(OES)의 Ca 함량 40.98%과 유사한 반면 그 외 무기질 성분은 K를 제외하고 모두 OES보다 상당히 감소하였다. 용해도는 젖산칼슘이 97.7%로 OES의 응해도 0.58%와 회화분의 용해도 3.43%에 비하여 월등히 높아, 젖산칼슘을 제조하여 이용하는 것이 칼슘제로서 의 이용률을 더욱 높일 수 있으리라 사료되었다.

• 한국수산과학회지
• /
• 제33권2호
• /
• pp.158-163
• /
• 2000

참치 통조림 부산물인 자숙 가다랑어뼈를 칼슘제로 이용하기 위하여 칼슘추출조건 (추출방법 및 시간) 및 그 특성에 대하여 살펴보았다. 다량의 지질이 혼재한 자숙 가다랑어뼈로부터 칼슘제로 제조하기 위한 추출방법으로는 회화처리가 고온가압처리 및 진탕 처리보다 어취가 없으면서 백색을 나타내어 적절하였고, 백색도 및 칼슘 가용화율로 미루어 회화처리 최적조건은 $900{\circ}C, 15분$이었다. 최적조건에서 회화처리한 칼슘제의 응집은 진탕시간이 경과할수록 증가하여 16시간에 $86.1{\%}$로 최고에 달하였고, 용액 pH가 산성조건 (pH 2-5)에서는 거의 일어나지 않았으나, 중성조건 (pH 6-8)에서 급격히 증가하여 최대에 이르렀고, 알칼리조건 (pH 9-11)에서는 중성조건과 거의 차이가 없었다. 이상의 결과로 보아 최적조건에서 처리한 칼슘제의 경우도 중성부근에서는 가용화율이 낮아 기능성 개선제 또는 고차 수산가공품의 탄력 증강 등과 같은 품질개선제로 이용되기 위하여는 용해도 개선을 위한 적절한 처리가 시도되어야 할 것으로 판단되었다.