• Title, Summary, Keyword: hydride generation method

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Selemium Intake in Breast-fed Infants during Course of Lactation

  • Kim, Eul-Sang;Keum, Hae-Kyoung;Yuzo Tamari
    • Preventive Nutrition and Food Science
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    • v.1 no.2
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    • pp.230-233
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    • 1996
  • The purposes of this study was to investigate selenium content of human milk and selenium intake of breast-fed infants at each period of lactation longitudinally. The human milk intake in breast-fed infants was measured by test weighing method from 20 lactating mothers at 1,2 and 3 months postpartum. Selenium content in the milks was determined by atomic absorption spectrophotometry with hydride generation after wet digestion of samples. Selenium intake in breast-fed infants was calculated by multiplying human milk intakes by selenium contents. The milk intakes were 640, 726 and 715g/day at 1,2 and 3 months postpartum. The selenium contents in human milk were characterized by a pattern of slight decline with advancing stage of lactation;13.1, 11.5 and 9.8$\mu\textrm{g}$/L at 1,2 and 3 months during lactation. There was a large individual variation at any stage of this study. The mean dietary selenium intakes in breast-fed infants were 8.38, 8.32 and 6.97$\mu\textrm{g}$/day at 1,2 and 3 months postpartum, respectively. The mean daily intakes on a body weight basis were gradually decreased during the course of lactation.

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Comparative Study on Effects of WPH and WPHCR on the anticonvulsive action and Accumulation of Hg & AS in Organ of ICR Mice (우황포용환(牛黃抱龍丸)과 우황포용환(牛黃抱龍丸) 거(去) 주사석웅황(朱砂石雄黃)의 항경련작용(抗痙攣作用) 및 Hg, As의 간(肝).신장(腎臟)에의 축적(蓄積)에 대(對)한 비교연구(比較硏究))

  • Kim Yun-Hee;Lee Han-Cheul
    • The Journal of Pediatrics of Korean Medicine
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    • v.8 no.1
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    • pp.59-74
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    • 1994
  • The Study was performed on the anticonvulsive effects of Woohwangporyonghwan(WPH) and Woohwangporyonghwan except CINNABARIS and REALGAR(WPHCR) in ICR mice pretreated with strychnine, picrotoxin, and caffeine as convulsive agents, and also was done on the accumulation of Hg & AS in organs of ICR mice by ICP hydride generation method. The results were obtained as follows: 1. WPH and WPHCR group showed significant effect in delaying the onset of convulsion induced by strichine, but time to death was effective only in WPHCR group. 2. WPH and WPHCR group were significantly effective in delaying convulsion induced by picrotoxin, and time to death. 3. The anticonvulsive effect of WPH and WPHCR group was not found convulsion induced by caffeine. 4. The accumulation of Hg, AS in liver and kidney of ICR mice was not determined below 50ng/g and below 80ng/g respectively. From the above results it could be concluded that WPH and WPHCR group were effective in the convulsions induced by strychnine and picrotoxin, although the accumulation of Hg & As in liver and kidney was not proved, further study might be necessary to prove the drug safety of WPH included CINNABARIS and REALGAR.

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Analytic study on arsenic content in plastic materials (플라스틱 소재의 비소 함유량 분석에 관한 연구)

  • Lee, Jae-In;Choi, Zel-Ho;Choi, Ki-In;Ko, Byung-Rae;Choi, In-Suk;Cho, Hun-Sik
    • Analytical Science and Technology
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    • v.25 no.6
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    • pp.402-409
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    • 2012
  • Quantitative analytical condition for arsenic in plastic materials by the flow injection-hydride generation-inductively coupled plasma-atomic emission spectrometry was studied. The plastic samples were dissolved by wet-acid digestion method and microwave-acid digestion method. The reproducibility and accuracy in this method was verified using of certified reference materials(CRMs) CRM-EC680k and CRM-EC681k. The analyical results agrees with certified value within the range of uncertainty. The results of CRM-EC680k wer 4.1~4.3 mg/kg (certified value $4.1{\pm}0.5$ mg/kg), and the results of CRM-EC681k were 28.9~30.6 mg/kg (certified value $29.1{\pm}1.8$ mg/kg).

Fuel cell system for SUAV using chemical hydride - II. Lightweight fuel cell propulsion system (화학수소화합물을 이용한 소형 무인항공기용 연료전지 시스템 연구 - II. 경량 연료전지 추진 시스템)

  • Hong, Ji-Seok;Park, Jin-Gu;Sung, Myeong-Hun;Jeon, Chang-Soo;Sung, Hong-Gye;Shin, Seock-Jae;Nam, Suk-Woo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.3
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    • pp.233-239
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    • 2013
  • A 100 W fuel cell system using chemical storage method has been applied for a propulsion system of the SUAV(Small Unmanned Aerial Vehicle). A fuel cell and battery have been combined for both the small/light hydrogen generation control system and the hybrid power supply system. A small hydrogen generation device was implemented to utilize NaBH4 aqueous solution and dead-end type PEMFC system, which were evaluated on the ground and by the flight tests. The system pressurized at a 45kpa stably operates and get higher fuel efficiency. The pressure inside of the hydrogen generation control system was maintained at between 45 kPa and 55 kPa. The 100W fuel cell system satisfies the required weight and power consumption rate as well as the propulsion system, and the fuel cell system performance was demonstrated through flight test.

Urinary Arsenic Concentrations and their Associated Factors in Korean Adults

  • Bae, Hye-Sun;Ryu, Doug-Young;Choi, Byung-Sun;Park, Jung-Duck
    • Toxicological Research
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    • v.29 no.2
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    • pp.137-142
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    • 2013
  • Arsenic (As) is a well-known human carcinogen and its dietary exposure has been found to be the major route of entry into general population. This study was performed to assess the body levels of As and their associated factors in Korean adults by analyzing total As in urine. Urine and blood samples were collected from 580 adults aged 20 years and older, who had not been exposed to As occupationally. Demographic information was collected with the help of a standard questionnaire, including age, smoking, alcohol intake, job profiles, and diet consumed in the last 24 hrs of the study. Total As, sum of As(III), As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), in urine was determined using atomic absorption spectrometer involving hydride generation method. The geometric mean concentration of total As in urine was $7.10{\mu}g/L$. Urine As was significantly higher in men ($7.63{\mu}g/L$) than in women ($6.75{\mu}g/L$). Age, smoking, alcohol consumption, and job profiles of study subjects did not significantly affect the concentration of As in urine. No significant relationship was observed between body mass index (BMI), Fe, and total cholesterol in serum and urinary As. Urine As level was positively correlated with seaweeds, fishes & shellfishes, and grain intake. A negative correlation between urinary As level and HDL-cholesterol in serum and meat intake was observed. Overall, these results suggest that urinary As concentration could be affected by seafood consumption. Therefore, people who frequently consume seafood and grain need to be monitored for chronic dietary As exposure.

Microstructure analyses of aluminum nitride (AlN) using transmission electron microscopy (TEM) and electron back-scattered diffraction (EBSD) (투과전자현미경과 전자후방산란회절을 이용한 AlN의 미세구조 분석)

  • Joo, Young Jun;Park, Cheong Ho;Jeong, Joo Jin;Kang, Seung Min;Ryu, Gil Yeol;Kang, Sung;Kim, Cheol Jin
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.25 no.4
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    • pp.127-134
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    • 2015
  • Aluminum nitride (AlN) single crystals have attracted much attention for a next-generation semiconductor application because of wide bandgap (6.2 eV), high thermal conductivity ($285W/m{\cdot}K$), high electrical resistivity (${\geq}10^{14}{\Omega}{\cdot}cm$), and high mechanical strength. The bulk AlN single crystals or thin film templates have been mainly grown by PVT (sublimation) method, flux method, solution growth method, and hydride vapor phase epitaxy (HVPE) method. Since AlN suffers difficulty in commercialization due to the defects that occur during single crystal growth, crystalline quality improvement via defects analyses is necessary. Etch pit density (EPD) analysis showed that the growth misorientations and the defects in the AlN surface exist. Transmission electron microscopy (TEM) and electron back-scattered diffraction (EBSD) analyses were employed to investigate the overall crystalline quality and various kinds of defects. TEM studies show that the morphology of the AlN is clearly influenced by stacking fault, dislocation, second phase, etc. In addition EBSD analysis also showed that the zinc blende polymorph of AlN exists as a growth defects resulting in dislocation initiator.

A Study on Electrolysis of Heavy Water and Interaction of Hydrogen with Lattice Defects in Palladium Electrodes (팔라디움전극에서 중수소의 전기분해와 수소와 격자결함의 반응에 관한 연구)

  • Ko, Won-Il;Yoon, Young-Ku;Park, Yong-Ki
    • Nuclear Engineering and Technology
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    • v.24 no.2
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    • pp.141-153
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    • 1992
  • Excess tritium analysis was peformed to verify whether or not cold fusion occurs during electrolysis of heavy water in the current density range of 83~600 mA/$\textrm{cm}^2$ for a period of 24 ~ 48 hours with use of palladium electrodes of seven different processing treatments and geometries. The extent of recombination of D$_2$ and $O_2$gases in the electrolytic cell was measured for the calculation of accurate enthaplpy values. The behavior and interaction of hydrogen atoms with defects in Pd electrodes were examined using the Sieverts gas charging and the positron annihilation(PA) method. Slight enrichment of tritium observed was attributed to electrolytic enrichment but not to the formation of a by-product of cold fusion. The extent of recombination of D$_2$and $O_2$gases was 32%. Hence the excess heat measured during the electrolysis was considered to be due to the exothermic reaction of recombination but not to nuclear fusion. Lifetime results from the PA measurements on the Pd electrodes indicated that hydrogen atoms could be trapped at dislocations and vacancies in the electrodes and that dislocations were slightly more preferred sites than vacancies. It was also inferred from R parameters that the formation of hydrides was accompanied by generation of mostly dislocations. Doppler broadening results of the Pd electrodes indicated that lattiec defect sites where positrons were trapped first increased and then decreased, and this cycle was repeated as electrolysis continued. It can be inferred from PA measurements on the cold-rolled Pd and the isochronally annealed Pd hydride specimens that microvoid-type defects existed in the hydrogen-charged electrode specimen.

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Improvement of analytical methods for arsenic in soil using ICP-AES (ICP-AES를 이용한 토양 시료 중 비소 분석 방법 개선)

  • Lee, Hong-gil;Kim, Ji In;Kim, Rog-young;Ko, Hyungwook;Kim, Tae Seung;Yoon, Jeong Ki
    • Analytical Science and Technology
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    • v.28 no.6
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    • pp.409-416
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    • 2015
  • ICP-AES has been used in many laboratories due to the advantages of wide calibration range and multi-element analysis, but it may give erroneous results and suffer from spectral interference due to the large number of emission lines associated with each element. In this study, certified reference materials (CRMs) and field samples were analyzed by ICP-AES and HG-AAS according to the official Korean testing method for soil pollution to investigate analytical problems. The applicability of HG-ICP-AES was also tested as an alternative method. HG-AAS showed good accuracies (90.8~106.3%) in all CRMs, while ICP-AES deviated from the desired range in CRMs with low arsenic and high Fe/Al. The accuracy in CRM030 was estimated as below 39% at the wavelength of 193.696 nm by ICP-AES. Significant partial overlaps and sloping background interferences were observed near to 193.696 nm with the presence of 50 mg/L Fe and Al. Most CRMs were quantified with few or no interferences of Fe and Al at 188.980 nm. ICP-AES properly assessed low and high level arsenic for field samples, at 188.980 nm and 193.696 nm, respectively. The importance of the choice of measurement wavelengths corresponding to relative arsenic level should be noted. Because interferences were affected by the sample matrix, operation conditions and instrument figures, the analysts were required to consider spectral interferences and compare the analytical performance of the recommended wavelengths. HG-ICP-AES was evaluated as a suitable alternative method for ICP-AES due to improvement of the detection limit, wide calibration ranges, and reduced spectral interferences by HG.