• Title, Summary, Keyword: mass spectrum

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Improvement of Spectrum Detection Algorithm for Mass Spectrometer (질량분석기를 위한 스펙트럼 검출 알고리즘의 개선)

  • Lee, Young Hawk;Choi, Hun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.1
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    • pp.47-54
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    • 2019
  • An improved method of spectrum detection algorithm for mass spectrum analysis system is proposed. In the conventional spectrum detection algorithm that utilizes the results of the linear approximation and quadratic curve fitting on the ion signal block of each mass index, it is possible to reduce the detection error in the mass spectrum detection by further improving the condition of eliminating the invalid ion signals. Also, the proposed method can reduce the estimation error of the peak value of the mass spectrum by using the result of quadratic curve fitting for the effective ion signal block in which the peak position error is corrected. To evaluate the effectiveness of the proposed method, computer simulations were carried out step by step using the measured ion signal. Also, by comparing the rate of false detection for several inputs, the proposed method showed better detection performance than the conventional method.

Improvement of Mass Spectral Detection Performance by Pre-correction of Peak Position Error (피크위치오차 사전 보정을 통한 질량 스펙트럼 검출 성능 개선)

  • Lee, Young Hawk;Heo, Gyeongyong;Choi, Hun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.6
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    • pp.666-674
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    • 2019
  • In the mass spectrum of the mass spectrometer, the spectrum of the low peak adjacent to the spectrum having the high peak value is connected to each other and thus the separation is difficult. This inter-spectral overlap causes degradation of the mass spectral detection performance and resolution. In this paper, we propose a method to improve the mass spectrum detection performance and peak accuracy of residual gas analyzer. The type discrimination according to the characteristics of the ion signal block and the pre-correction for the peak position error can separate and detect the spectrum of the low peak connected to the adjacent spectra. To verify the performance of the proposed method, we compared the proposed method with the conventional method in simulations using actual ion signals obtained from the mass spectrometer under development.

Algorithm to Improve Mass Spectral Resolution of Gas Chromatography Mass Spectrometer (가스크로마토그래피 질량분석기의 질량 스펙트럼 해상도 개선 알고리즘)

  • Choi, Hun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.9
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    • pp.1232-1238
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    • 2018
  • This paper proposes methods for improving mass spectral resolution for a gas chromatograph mass spectrometer. The slope signs of the 1st and 2nd fitting functions for the ion signal block of each mass index are obtained, and the unnecessary element signals in the ion signal block are removed. The spectrum can be obtained by obtaining the second-order fitting function of the reconstructed ion signal block using only the effective ion signals. In addition, the resolution of the mass spectrum can be improved by correcting the error caused by the shift of the spectral peak position. To verify the performance of the proposed methods, computer simulations were performed using the actual ion signals obtained from the GC-MS system under development. Simulation results show that the proposed method is valid.

Recent results on IceCube multi-messenger astrophysics

  • Rott, Carsten
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.54.2-54.2
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    • 2019
  • Mass and radius of a neutron star in low-mass X-ray binary (LMXB) can be estimated simultaneously when the observed light curve and spectrum show the photospheric radius expansion feature. This method has been applied to 4U 1746-37 and the mass and radius were found to be unusually small in comparison with typical neutron stars. We re-estimate the mass and radius of this target by considering that the observed light curve and spectrum can be affected by other X-ray sources because this LMXB belongs to a very crowded globular cluster NGC 6441. The new estimation increases the mass and radius but they do not reach the typical values yet.

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Improvement of protein identification performance by reinterpreting the precursor ion mass tolerance of mass spectrum (질량스펙트럼의 펩타이드 분자량 오차범위 재해석에 의한 단백질 동정의 성능 향상)

  • Gwon, Gyeong-Hun;Kim, Jin-Yeong;Park, Geon-Uk;Lee, Jeong-Hwa;Baek, Yung-Gi;Yu, Jong-Sin
    • Bioinformatics and Biosystems
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    • v.1 no.2
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    • pp.109-114
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    • 2006
  • In proteomics research, proteins are digested into peptides by an enzyme and in mass spectrometer, these peptides break into fragment ions to generate tandem mass spectra. The tandem mass spectral data obtained from the mass spectrometer consists of the molecular weights of the precursor ion and fragment ions. The precursor ion mass of tandem mass spectrum is the first value that is fetched to sort the candidate peptides in the database search. We look far the peptide sequences whose molecular weight matches with precursor ion mass of the mass spectrum. Then, we choose one peptide sequence that shows the best match with fragment ions information. The precursor ion mass of the tandem mass spectrum is compared with that of the digested peptides of protein database within the mass tolerance that is assigned by users according to the mass spectrometer accuracy. In this study, we used reversed sequence database method to analyze the molecular weight distribution of precursor ions of the tandem mass spectra obtained by the FT LTQ mass spectrometer for human plasma sample. By reinterpreting the precursor ion mass distribution, we could compute the experimental accuracy and we suggested a method to improve the protein identification performance.

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An extension of new laser pulse atom-probe construction and time-of-flight mass spectrum of $H_2$ and He gas (A new laser pulse atom-probe 제작 및 $H_2$ 가스와 He 가스의 time-of-flight mass spectrum)

  • 송순달;홍남관
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.7 no.3
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    • pp.465-472
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    • 1997
  • An extension of new test methods for surfaces with an apparatus based on photon-induced desorption and ionisation in the electric field, is constructed and tested, It also investigates how to show the efficiency of the arrangement adsorbates $H_2$ and He on W(110). The field emitter temperature was 80 K. The wavelength of light used was 193 nm with field strengths between 10 and 50 V/nm. Many ion fragments($CO^+, He^+, H_2^^+, H_2O^+, W^{3+}\; and\; W^{2+}$) were produced by an electronic stimulation of the adsorbate with the help of a photon energy of 6.4 eV at He and $H_2$/W(110). A transient recorder enables the registration of the entire mass spectrum.

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Noise Reduction Algorithm For The Detection of Fine Ion Signals in Residual Gas Analyzer (잔류가스분석기의 질량 스펙트럼 검출 성능 향상을 위한 잡음제거 알고리즘)

  • Heo, Gyeongyong;Choi, Hun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.68 no.1
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    • pp.102-107
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    • 2019
  • This paper proposes a method to improve the mass spectral detection performance of the residual gas analyzer. By improving the mode estimation method for setting the threshold value and improving the additive noise elimination method, it is possible to detect mass spectrums having low peak values of the threshold level difficult to distinguish from noise. Ion signal blocks for each mass index with noise removed by the improved method are effective for eliminating invalid ion signals based on the linear and quadratic fittings. The mass spectrum can be obtained from the quadratic fitted curves for the reconstructed ion signal block using only the valid ion signals. In addition, the resolution of the mass spectrum can be improved by correcting the error caused by the shift of the spectral peak position. To verify the performance of the proposed method, computer simulations were performed using real ion signals obtained from the residual gas analysis system under development. The simulation results show that the proposed method is valid.

Influence of Sample Preparation Method and Silver Salt Types on MALDI-TOFMS Analysis of Polybutadiene

  • Choi, Sung-Seen;Ha, Sung-Ho
    • Macromolecular research
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    • v.16 no.2
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    • pp.108-112
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    • 2008
  • Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis of nonpolar polymeric materials is affected by the sample preparation as well as the matrix and cationizing agent. This study examined the influence of silver salt types on the MALDI analysis of polybutadiene (PB). Silver trifluoroacetate (AgTFA), silver benzoate (AgBz), silver nitrate ($AgNO_3$), and silver p-toluenesulfonate (AgTS) were used as the silver salts to compare the MALDI mass spectra of PB. The mixture solution of PB and 2,5-dihydroxybenzoic acid (DHB), as a matrix dissolved in THF, was spotted on the sample plate and dried. A droplet of the aqueous silver salt solution was placed onto the mixture. The mass spectrum with AgBz showed the clear $[M+Ag]^+$ ion distribution of PB while the mass spectrum with AgTFA did not show $[M+Ag]^+$ ions but only silver cluster ions. The mass spectra with $AgNO_3$ and AgTS did not show a clear $[M+Ag]^+$ ion distribution. The difference in the formation of $[M+Ag]^+$ ions of PB depending on the silver salts was attributed to the silver cation transfer reaction between the silver salt and the matrix (DHB). The mass spectrum showed a clear $[M+Ag]^+$ ion distribution of PB when the conjugate acid of the silver salt was less acidic than the matrix.

Design of Active Mass Damper to Improve Seismic Performance Using Capacity Spectrum Method (내진성능 향상을 위한 능력스펙트럼법에 의한 능동제어기 설계)

  • 김형섭;민경원
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.259-266
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    • 2003
  • This paper begins with the seismic performance evaluation of an existing building, which exhibits the need of additional damping to reduce its response. Required damping ratio is found by capacity spectrum method to satisfy a target response. It is expressed with the design parameter of active mass damper by adopting Linear Quadratic Regulator, Optimal gains are obtained and then weighting matrices are found. Finally the seismic performance by added active mass damper is demonstrated, which satisfies the target response.

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Estimating Mass and Radius of a Neutron Star in Low-Mass X-ray Binary

  • Kwak, Kyujin;Sung, Kwang Hyun;Kim, Young-Min;Kim, Myungkuk;Lee, Chang-Hwan
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.1
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    • pp.48.1-48.1
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    • 2019
  • Mass and radius of a neutron star in low-mass X-ray binary (LMXB) can be estimated simultaneously when the observed light curve and spectrum show the photospheric radius expansion feature. This method has been applied to 4U 1746-37 and the mass and radius were found to be unusually small in comparison with typical neutron stars. We re-estimate the mass and radius of this target by considering that the observed light curve and spectrum can be affected by other X-ray sources because this LMXB belongs to a very crowded globular cluster NGC 6441. The new estimation increases the mass and radius but they do not reach the typical values yet.

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