• 한국표면공학회지
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• 제18권4호
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• pp.153-163
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• 1985

In the electroless nickel plating bath which contained nickel sulfate, sodium hypophosphite, boric acid and triethanolamine, effect of their concentration on the rate of deposition was tested by gravimetric method and polarization method. The polarization method that polarize small range of voltage anodicaly and cathodicaly at the mixed potential in the electroless plating bath can calculate mixed current (depositing rate) from $i_{mp}=\frac {i}{\eta}\;\frac{RT}{nF}\;or\;i_{mp}=\frac{i}{\eta}\;\frac{1}{2.3}(\frac{b_a\;\;b_c}{b_c+b_a})$ Where $i_{mp}$ is the depositing current, i is the polarized current, ${\eta}$ is the polarized voltage, $b_a\;and\;b_c$ are the Tafel slop of anodic and cathodic polarization curves respectively. The calculated mixed current ($i_{mp}$) is proportional to the depositing rate obtained by gravimetric method and corresponded mostly to the real depositing rate by multifying supplementary constant. The polarization method can be used for founding inclination of reaction on various concentration of each composition. Decreasing or increasing concentration of triethanolaminc as a complexing agent , the depositing rate is decreased and when the bath contained 25-50mL/L of triethanoloamine, the depositing rate is increased. The depositing rate is increased with increasing the concentration of boric acid, and when the bath contained 0.5M of boric acid, the depositing rate is increased abruptly. The optimum composition of the electroless nickel bath was estimated 0.1M of nickel sulfate, 0.25M of sodium hypophosphite, 0.5M of boric acid, and 25-50mL/L of triethanalamine.

• Journal of the Korean Wood Science and Technology
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• 제45권6호
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• pp.836-845
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• 2017

Gravimetric method is usually used to evaluate air-dry density, which is governing physical or mechanical properties of wood. Although it had high evaluation accuracy, the method is time consuming process. Thus, this study was conducted to estimate air-dry density of wood with high accuracy by using polychromatic X-ray and digital detector as alternative of gravimetric method. To quantify polychromatic X-ray projection for evaluating air-dry density, Lambert-Beer's law with the integral value of probability function was used. The integral value was used as weighting factor in the law, and it was determined by conducting simple test at various penetration depths and tube voltage. Mass attenuation coefficient (MAC) of wood also calculated by investigating polychromatic X-ray projection according to species, penetration depth and tube voltage. The species had not an effect on change of MAC. Finally, an air-dry density of wood was estimated by applying the integral value, MAC and Lambert-Beer's law to polychromatic X-ray projection. As an example, the relation of the integral value (${\alpha}$) according to penetration depth (t, cm) at tube voltage of 35 kV was ${\alpha}=-0.00091t{\times}0.0184$ while the regression of the MAC (${\mu}$, $cm^2/g$) was ${\mu}=0.5414{\exp}(-0.0734t)$. When calculation of root mean squared error (RMSE) was performed to check the estimation accuracy, RMSE at 35, 45 and 55 kV was 0.010, 0.013 and $0.009g/cm^3$, respectively. However, partial RMSE in relation to air-dry density was varied according to tube voltage. The partial RMSE below air-dry density of $0.41g/cm^3$ was $0.008g/cm^3$ when tube voltage of 35 kV was used. Meanwhile, the partial RMSE above air-dry density of $0.41g/cm^3$ decreased as tube voltage increased. It was conclude that the accuracy of estimation with polychromatic X-ray and digital detector was quite high if the integral value and MAC of wood were determined precisely or a condition of examination was chosen properly. It was seemed that the estimation of air-dry density by using polychromatic X-ray system can supplant the gravimetric method.

• Applied Biological Chemistry
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• 제40권3호
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• pp.220-224
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• 1997

아밀로오스 함량이 다른 옥수수 전분에 전분과 물의 비율을 1:3.5와 1:9로 조절하고 $100^{\circ}C$와 $121^{\circ}C$에서 가열-냉각 처리를 4회까지 반복한 후, 효소-중량법과 ${\alpha}-$아밀라아제(Bacillus subtilis)를 이용한 효소법으로 효소저항전분을 분리하여 수분함량과 가열-냉각 방법에 따른 효소저항전분의 수율을 비교하였다. 같은 처리를 한 경우에는 효소-중량법이 ${\alpha}-$아밀라아제를 사용한 효소법보다 효소저항전분의 분리능이 더 큼을 알 수 있었다. 분리 방법에 상관없이 아밀로오스 함량이 높고, 가열-냉각 처리 횟수를 증가시키면 효소저항전분의 수율도 증가하였으며, 가열온도는 $100^{\circ}C$보다 $121^{\circ}C$에서, 수분함량은 전분과 물의 비을이 1:9보다 1:3.5의 조건에서 높은 수율을 보였다.

• 환경영향평가
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• 제19권4호
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• pp.421-429
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• 2010

The reliability of the measurement of ambient trace species is an important issue, especially, in background area such as Gosan in Jeju Island. In a previous episodic study, it was suggested that the PM10 measurement result by the gravimetric method(GMM) was not in agreement with the result by the ${\beta}$-ray absorption method(BAM). In this study, a systematic comparison was carried out for the data between 2001 and 2008 at Gosan(GMM and BAM) and Jeju city (BAM) which is near to Gosan. It was found that at Gosan the PM10 concentration by BAM was higher than GMM and the correlation between them was low. The BAM results at Gosan and Jeju city showed similar trend implying the discrepancy at Gosan was not caused by instrumental problem of the BAM at Gosan. Based on the previous studies two probable reasons for the discrepancy are identified; (1) negative measurement error by the evaporation of volatile ambient species at the filter in GMM such as nitrate and ammonium and (2) positive error by the absorption of water vapor during measurement in BAM. There was no heater at the inlet of BAM at Gosan during the sampling period. Based on the size-segregated measurement data, it was identified that the evaporation error was minor, if any. The relationship between the two methods did not vary with the ambient relative humidity. Thus, at present, it is not clear why the discrepancy had been occurring and when using the PM10 data at Gosan, one should be aware the possible errors.

• 대한기계학회논문집B
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• 제30권6호
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• pp.497-504
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• 2006

A Coriolis mass flowmeter(CMF), which has U-Shaped unique measurins tube was developed fo. direct mass flow measurement. In order to convert the time difference between two measuring tubes motion into mass flowrate and flow quantity, a signal processing circuit, as a part of CMF, was also developed. The CMF was designed as the 15 mm nominal diameter of pipe connection and the 8 mm stainless steel(sus 316) pipe was used for measuring tube. To maximize the flow signal(time difference) from the measuring tubes, the natural frequency of measuring tube was adjusted as 220 Hz, which is same as the frequency of exciter. The maximum displacement at the end of the measuring tube was measured as 0.05 mm and the maximum time difference between two measuring tubes was observed as $20{\mu}s$, which was proper for discrimination and measuring range of CMF. The developed CMF was tested against the gravimetric flowmeter calibrator in the range of 3 kg/min and 30 kg/min. The results showed that the CMF has good linearity and repeatability in the tested flow range. Large size of CMF base on the current study experience will be developed.

• 한국유체기계학회 논문집
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• 제17권4호
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• pp.5-10
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• 2014

It is possible for the nation's largest flowmeter calibration system in K-water to calibrate flow rate up to $2,700m^3/h$ and diameter 800mm. However, the calibration and measurement capability of K-water's system is not satisfied in comparison with other developed countries. In this study, we find the dominant factors related to the uncertainty of weight and time measurement for gravimetric flowmeter calibration system. As a results of improving the system, the combined standard uncertainty has been improved $1.099{\times}10^{-3}$ to $2.332{\times}10^{-4}$. So calibration and measurement capability got 0.08 percent of the relative expanded uncertainty for maximum flow rate using the coverage factor(k=2).

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2002년도 추계학술대회 논문집
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• pp.276-277
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• 2002

One of drawbacks of the inertial impactor measurement is the required long sampling time (Keskinen et al., 1992). In a gravimetric method, an impaction substrate must be weighed and placed on the corresponding collection plate before being assembled. After sampling, the inertial impactor is disassembled and the collection plate is weighted again. The sampling time depends on the sampled particle mass because the collected particle mass must be sufficiently high to be measured by a sensitive microbalance. (omitted)

• 한국토양비료학회지
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• 제21권4호
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• pp.367-372
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• 1988

중량법(重量法)에 의(依)한 토양수분함량(土壤水分含量)과 중성자(中性子) 및 Gypsum-block을 이용(利用)하여 측정(測定)한 토양수분함량(土壤水分含量)에 대(對)하여서, 오차분석(誤差分析)을 통(通)하여 각(各) 측정방법(測定方法)에 의(依)한 토양수분함량(土壤水分含量)의 오차범위(誤差範圍) 및 각(各) 방법간(方法間) 같은 정밀도(精密度)를 얻기위(爲)해 필요(必要)한 측정(測定)반복수를 구명(究明)코자 사양토(砂壤土)에서 시험(試驗)한 결과(結果)는 다음과 같았다. 1. 토양수분함량(土壤水分含量)의 오차(誤差)와 토양수분함량(土壤水分含量)과의 관계(關係)는 중량법(重量法)과 중성자(中性子)를 이용(利用)한 경우는 2차함수(次函數)의 양상(樣相)을, Gypsum-block의 경우는 지수함수(指數函數)의 양상(樣相)을 나타냈다. 2. 토양수분함량(土壤水分含量)이 11~33%(용적함량)인 범위에서 중량법(重量法)에 의(依)한 토양수분함량(土壤水分含量)의 오차(誤差)는 평균(平均) 1.11%이었으며 오차(誤差)의 범위(範圍)(Range)는 0.28~3.49%이었다. 3. 표토용(表土用) 중성자(中性子)를 이용(利用)한 토양수분측정방법(土壤水分測定方法)에 의(依)한 토양수분함량(土壤水分含量)의 오차(誤差)는 평균(平均) 1.15%이었으며 오차(誤差)의 범위는 0.71~2.63%으로써 그 경향이 중량법(重量法)과 유사하였고, 심토용(深土用) 중성자(中性子)를 이용(利用)한 수분측정방법(水分測定方法)에 의(依)한 오차(誤差)는 평균(平均) 0.70%이었으며 그 범위는 0.52~1.01%으로써 가장 작았다. 4. Gypsum-block에 의(依)해 토양수분장력(土壤水分張力)을 측정(測定)한 후(後) 토양수분특성(土壤水分特性)곡선을 이용(利用)하여 토양수분함량(土壤水分含量)을 추정(推定)할때, 오차(誤差)의 범위는 0.05~21.89%이었으며, 토양수분함량(土壤水分含量)이 증가(增加)할수록 오차(誤差)는 크게 증가(增加)는 경향이었다. 5. 사양토(砂壤土)에서 토양수분함량(土壤水分含量)이 약 14% 이상(以上)인 경우에는 심토용(深土用) 중성자(中性子)를 이용(利用)한 방법(方法)으로 토양수분함량(土壤水分含量)을 측정(測定)하는 것이 그 오차(誤差)가 작았으며, 토양수분함량(土壤水分含量)이 약 14% 이하(以下)인 경우에는 Gypsum-block을 이용(利用)하는 것이 그 오차(誤差)가 작았다. 6. 중량법(重量法)에 의(依)한 10반복 측정(測定)의 평균(平均) 토양수분함량(土壤水分含量)과 같은 정밀도(精密度)를 얻기 위(爲)한 반복수는 표토용(表土用) 중성자(中性子)를 이용(利用)한 수분측정방법(水分測定方法)의 경우 6~17, 심토용(深土用) 중성자(中性子)를 이용(利用)한 수분측정방법(水分測定方法)의 경우 0.7~8 및 Gypsum block의 경우 0.1~1,252이었다.

• 한국측량학회지
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• 제27권6호
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• pp.699-710
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• 2009

한 국가에서 지오이드모델은 그 나라의 일관된 표고기준면을 제공함으로써 정확한 정표고를 결정할 수 있게 하며, 국가기준점의 평면위치 결정시 지오이드고를 고려한 측지망 조정계산을 실시함으로써 좌표결정의 정확도를 높일 수 있다. 본 연구는 말레이시아나 인도네시아와 비슷한 조건의 동남아시아 국가인 필리핀이 자국의 지오이드모델을 어떻게 개발하는 것이 최선인지 그 방법론을 연구한 연구이다. 따라서 본 연구에서는 전반적인 지오이드 결정이론을 살펴보고, 아시아 국가들에서의 지오이드 개발사례를 통하여 필리핀 일원에 가장 적합한 지오이드 모델 개발방안을 제시하고자 하였으며, 필리핀 일원에서 최신의 지구중력장 모델인 EGM2008을 해석하여 지오이드고와 중력이상을 계산하였다. 연구결과 항공중력방법에 기반한 중력 지오이드모델을 개발하고, 200점 내외의 GPS/leveling데이터에 의한 기하학적 지오이드고를 합성하여 하이브리드 지오이드 모델을 개발하는 것이 가장 합리적인 방법으로 연구되었다. 또한 스토크스적분의 수행은 4밴드 구면 FFT방법이, 중력지오이드모델 개발에는 EGM2008과 SRTM에 의한 remove and restore 기법이, 하이브리드 지오이드모델의 개발에는 Least square collocation 알고리즘이 제안되었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.636-639
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• 2009

Fuel consumption measurement of Hydrogen fuel cell vehicle is considerably different form internal combustion engine vehicle such as carbon balance method. A practical method of fuel Consumption measurement has been developed for Hydrogen fuel cell vehicles. There are three method of hydrogen fuel consumption testing, gravimetric, PVT(Pressure, Volume and temperature), and Coriolis mass flow, all of which necessitate physical measurements of the fuel supply. The purpose of this research is to measure the fuel consumption of hydrogen fuel cell vehicles on chassis-dynamometer and to give information when the research is intended to develop method to measure hydrogen fuel consumption.