• Title/Summary/Keyword: Trace analysis

Search Result 1,357, Processing Time 0.027 seconds

Determination of Vitamin $B_{12}$ in Foods Using Column-Switching Technique in $\mu$-HPLC ($\mu$-HPLC의 Column-Switching 기술을 이용한 식품중 비타민 $B_{12}$의 분석)

  • 박성진;김혜경;함태식;김병용
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.28 no.6
    • /
    • pp.1208-1211
    • /
    • 1999
  • Semi HPLC using a column switching technique was used to determine the trace content of vitamin B12 in various foods. Total analytical time required less than 20 mins per sample and the recovery ratio was 99.9, 99.6, 100.1 and 99.8% for 1.0, 10.0, 100.0 and 1,000 g/kg, respectively. The content of vitamin B12 in various foods obtained using column switching method showed higher levels compared to labels in dried milk(0.5 g/100g) and in grain products(0.51~34.36 g/100g). Thus, this column switching method was more sensitive, effective and precise than the microbiological analysis currently used to determine the trace compounds like a vitamin B12.

  • PDF

Relationships in Cd, Hg, Pb and Zn Concentrations Between Hair and Internal Organs of Korean (한국인 모발과 내부장기조직간 Cd, Hg, Pb 및 Zn함량의 상호관련성)

  • 유영찬;이상기;양자열;김기욱;이수연;정규혁
    • Environmental Analysis Health and Toxicology
    • /
    • v.17 no.1
    • /
    • pp.21-27
    • /
    • 2002
  • In order to study the relationships between trace element concentrations of hair and internal organs, autopsy samples of hair, liver, kidney cortex, kidney medulla, heart, lung, spleen, cerebrum, testis and bone from 162 Korean subjects were analyzed for Cd, Hg, Pb and Zn by inductively coupled plasma atomic emission spectrometry. High significant positive correlations were found between the Cd concentration in hair and bone and Pb in hair and lung. Hair Hg levels were highly significantly correlated with organ Hg levels in the liver, kidney cortex, kidney medulla, heart, lung, spleen, cerebrum, testis and bone. And hair Zn levels were highly significantly correlated with organ Zn levels in the kidney cortex, kidney medulla, spleen, testis and bone.

Silent Verbs in Northern Mandarin: A Silence Neither Gaps Nor Emptiness Can Fill

  • Kim, Ji-Yung
    • Language and Information
    • /
    • v.11 no.2
    • /
    • pp.87-103
    • /
    • 2007
  • This paper reanalyzes examples with missing verbs. Northern Mandarin rejects argument nominal phrases after a silent verb, as well as silent verbs inside islands. These restrictions suggest a grammatical process which silences verbs. I propose that these restrictions are the result of VP-topicalization followed by ellipsis. This analysis accounts for the island sensitivity of these constructions: since VP-topicalization feeds ellipsis, constructions with elided VPs are not derivable from configurations where movement is impossible. Also, to avoid topicalization along with the VP, the argument must move out of VP; the subsequent topicalization of the VP containing the argument's trace would then give rise to a configuration where that trace c-commands the moved-out DP. Adjuncts do not pose a problem because they are located outside of that smallest VP-shell. The data presented here are accommodated by neither of Tang's (2001) proposals for silent verbs (gapping and empty verbs). Instead, they provide support for a third source for silent verbs, VP-ellipsis via topicalization.

  • PDF

Design and Implementation of the Linux Kernel Backdoor Intruder Tracing-Response System (리눅스 커널 백도어 침입자 추적대응시스템 설계 및 구현)

  • Jeon, Wan-Keun
    • Convergence Security Journal
    • /
    • v.5 no.2
    • /
    • pp.43-50
    • /
    • 2005
  • This paper is about the method that chases the Linux kernel backdoor intruder and copes with the kernel backdoor attack. We have a limit to trace the hacker with the current log analysing method because the hacker generally removes the log file and use the forge IP information. I propose the solution to solve the problem with the DeFor system. Through the restoration of the deleted log file, analysis of it and full HDD image, promptly quick response, it is possible to trace hacker spot and reduce hacking damage.

  • PDF

An Analytical Study on the Structural Behavior of Composite Beams (합성보의 거동에 관한 해석적 연구)

  • 황영서;양구록;송준엽;권영봉
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 1998.10a
    • /
    • pp.175-182
    • /
    • 1998
  • An analytical study to trace the nonlinear structural behavior of composite beams is undertaken to include the nonlinear material properties of steel sheeting, reinforcing steel bar and concrete. To trace Moment-curvature relations, sectioning analysis method and two simple formulas are developed. A simple power model which has been originally used to expect the flexural capacity of the beam to column connections is proposed and the second formula is composed of two experimental functions to express the Moment-curvature relation in the elastic and plastic range separately. The load-deflection behavior of the beams has been simulated by the step-by-step numerical integration method and is compared with the test results available.

  • PDF

Determination of Trace Aldehydes in Ambient Air by Liquid Chromatography (액체 크로마토그래프법에 의한 대기시료중 미량 알데히드류의 정량)

  • 이용근;정태우
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.11 no.4
    • /
    • pp.339-349
    • /
    • 1995
  • The purpose on this study is to optimize the chromatographic determination method of trace aldehydes in ambient air. Carbonyl compounds in urban air were trapped at $C_{18}$ DNPH-coated cartridges, and generated hydrazone derivatives were separated by HPLC and detected by UV-vis spectroscopic detector at 360nm. Formaldehyde and acetaldehyde compounds could be isolated from urban(Seoul) air with more than 95% collection efficiency. The analytical detection limits for formaldehyde and acetaldehyde are 0.06pp $b_{v}$, 0.08pp $b_{v}$ for 108 L air samples, respectively. The precision of this method are 3 .sim. 4%(RSD) for mutiple injection of hydrazone standards. Separation of seven dinitrophenylhydrazones could be achieved in appoximately 20 minutes operation time using $C_{18}$ column with apprepriate eluent. The method was applied to the analysis of aldehydes and ketone in Seoul ambient air. The 24-h ambient levels of formaldehyde, acetaldehyde reached up to 6 .sim. 14 and 3 .sim. 8ppbv, respectively. The daily average concentration ratio were 0.60 for acetaldehyde/formaldehyde.yde.

  • PDF

A Study of the Trace Elements in Sea-weed (Dried Laver) (한국산 김중의 미량금속 함량 조사연구)

  • 윤혜경;노영수
    • Environmental Analysis Health and Toxicology
    • /
    • v.12 no.3_4
    • /
    • pp.67-73
    • /
    • 1997
  • This study was carried out to investigate the contents of heavy metals such as iron, copper, lead, cadmium, magnesium, platium in connection with water pollution in sea weed (dried laver) collected from the west, south, south- west, and east coasts of Korea. The results of the study are as follows; Iron was shown the highest value (1.280ppm) in the wild laver from the south coast. Copper was detected in larger qauntities (0.169 ppm) in green laver than in any other kinds of laver observed in this study. Lead was detected in larger quantities (0.195ppm) in the usual laver and green laver from the south-west coast as compared with the other coasts. Although cadmium and platium was also detected from every kind of laver, the concentrations were not over the allowance of the residual.

  • PDF

Kinetic Spectrophotometric Determination of Trace Amounts of Sulfide

  • Barzegar, Mohsen;Jabbari, Ali;Esmaeili, Majid
    • Bulletin of the Korean Chemical Society
    • /
    • v.24 no.9
    • /
    • pp.1261-1264
    • /
    • 2003
  • A method for the determination of trace amount of sulfide based on the addition reaction of sulfide with methyl green at pH 7.5 and $25{\circ}C$ is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 637 nm by the initial rate and fixed time method. The calibration graph is linear in the range 30-1200 ppb. The theoretical limit of detection was 0.014 ppm. Seven replicate analysis of a sample solution containing 0.70 ppm sulfide gave a relative standard deviation of 1.5%. The interfering effects of various ions on sulfide determination have been reported and procedures for removal of interference have been described. The proposed method was applied successfully to the determination of sulfide in tap and wastewater samples.

Error Performance Analysis of a FEC for the Cable Modem (유선 케이블 모뎀의 FEC 성능평가)

  • 이창재;김경덕;최형진
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.26 no.11A
    • /
    • pp.1803-1811
    • /
    • 2001
  • In this paper, Forward Error Correction(FEC) that is satisfied with ITU-T Recommendation J.83, Annex B(North American Data Over Cable Service Interface Specifications(DOCSIS) for Multimedia Cable Network System(MCNS)) is analyzed. The FEC consist of Reed-Solomon(RS) layer, interleaving layer, randomization layer, and trellis coded modulation(TCM) layer. The effects of quantization of input symbol and of trace-back depth in the Viterbi decoder are simulated over AWGN channels.

  • PDF

Guidelines for Applying Traceability in RUP (Rational Unified Process(RUP)의 추적성 적용 지침)

  • 소동섭;김수동
    • Proceedings of the Korean Information Science Society Conference
    • /
    • 2001.04a
    • /
    • pp.583-585
    • /
    • 2001
  • RUP의 Unified Process Model 에는 Use-Case Model, Analysis Model, Design Model, Deployment Model, Implementation Model, Test Model의 6가지 모델이 있다. 이 모델들은 모두 일관성이 있다. 한 모델에서 나오는 요소들은 전, 후 단계에서 다른 모델들과 Trace Dependencies를 갖는다. 예를 들면, Use-Case Model에서는 한 Use Case는 Design Model에서 Use-Case Realization으로 Test Model에서는 Test Case로 Trace Dependencies를 갖는다. 소프트웨어 개발에서 추적성은 Understandability와 Change Propagation 과 같은 이유로 매우 중요하다. 그러나 RUP에서는 각 모델들간의 추적성에 대한 지침이 충분히 제시되어 있지 않아, 개발 과정중에 요구사항의 변경이나 에러 수정 또는 향후 관리 시에 어려움을 겪고 있다. 본 논문에서는 이 점에 중점을 두고 RUP에서 제시하고 있는 모델들 간의 추적성 중 설계모델에서 분석모델로의 추적성 적용지침을 제시한다.

  • PDF