• 제목/요약/키워드: Mass Science

검색결과 9,492건 처리시간 0.038초

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

  • 곽규진;성광현;김영민;김명국;이창환
    • 천문학회보
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    • 제44권1호
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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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Effects of Muscle Mass and Fiber Number of Longissimus dorsi Muscle on Post-mortem Metabolic Rate and Pork Quality

  • Ryu, Youn-Chul;Choi, Young-Min;Kim, Byoung-Chul
    • Food Science and Biotechnology
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    • 제14권5호
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    • pp.667-671
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    • 2005
  • The aim of this study is to investigate the effects of the muscle mass and fiber number on post-mortem metabolic rates and pork quality. Carcass traits, muscle fiber characteristics, and type of fiber composition were evaluated using a sample of 200 cross-bred pigs. The muscle mass was divided into two groups according to carcass weight and loin-eye area measurements (heavy or light). In addition, the muscle histological characteristics were divided into two groups according to the muscle fiber density and total number of muscle fibers (high or low). All the carcass traits were significantly different in the muscle mass groups. Increasing weight significantly affected the cross-sectional area (CSA) of all fibers. The low group, which had a low muscle fiber number indicating a larger CSA of fibers, and especially the heavy-low group had the highest CSA levels of fibers. The fiber number percentage and the area percentage were significantly different in the groups categorized by fiber number. The heavy-high group indicated a normal rate of pH decline and the R-value. In addition, pigs with a heavy muscle mass and high muscle fiber number indicated normal drip loss, lightness, and protein denaturation. The present results suggest that increasing the total muscle fiber number has a beneficial effect on increasing the muscle mass without deteriorating the meat quality.

Effect of a Pholiota adiposa Extract on Fat Mass in Hyperlipidemic Mice

  • Cho, Soo-Muk;Lee, Young-Min;Lee, Dae-Hyoung;Chun, Hye-Kyung;Lee, Jong-Soo
    • Mycobiology
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    • 제34권4호
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    • pp.236-239
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    • 2006
  • The purpose of this study was to investigate the effect of a Pholiota adiposa extract on fat mass in hyperlipidemic mice fed on a high-fat diet. The water extracts from P. adiposa (ASI 24018) were not affected in the total triglyceride contents and epididymal fat mass in mice fed on a high-fat diet, but the retroperitoneal fat mass decreased significantly. This result suggests that the P. adiposa extract may be a potential candidate for use as a functional food that can act as a prophylactic against hyperlipidemia. However, the P. adiposa extract showed no effect in the total triglyceride contents and epididymal fat mass.

효모 탐색을 위한 Pyrolysis Mass Spectrometry의 활용 (Application of Pyrolysis Mass Spectrometry on Yeast Screening)

  • 신기선;신용국;권오유;이상한
    • 생명과학회지
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    • 제11권1호
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    • pp.19-23
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    • 2001
  • To develop the effective microbial screening method, pyrolysis mass spectrometry (PyMS) fingerprinting was evaluated as a tool that discriminate various yeast strains. The target yeast strains were isolated from industrial wastewater. Seventeen environmental isolated yeast strains were examined by pyrolysis mass spectrometry and sequencing analysis of the large subunit rRNA gene D1/D2 region. The PyMS results were compared with those of sequencing analysis. Taxonomic correlations were observed between the PyMS data and the sequencing results. It was concluded that PyMS provides a rapid, reliable and cost-reducing method for discrimination of the yeast strains.

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High-resolution ALMA Study of the Proto-Brown-Dwarf Candidate L328-IRS

  • Lee, Chang Won;Kim, Gwanjeong;Myers, Philip C.;Saito, Masao;Kim, Shinyoung;Kwon, Woojin;Lyo, A-Ran;Soam, Archana;Kim, Mi-Ryang
    • 천문학회보
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    • 제43권2호
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    • pp.39.1-39.1
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    • 2018
  • We present our observational attempts to precisely measure the central mass of a proto-brown dwarf candidate, L328-IRS, in order to investigate whether L328-IRS is in the substellar mass regime. Observations were made for the central region of L328-IRS with the dust continuum and CO isotopologue line emission at ALMA band 6, discovering the detailed outflow activities and a deconvolved disk structure of a size of ${\sim}87AU{\times}{\sim}37AU$. We investigated the rotational velocities as a function of the disk radius, finding that its motions between 130 AU and 60 AU are partially fitted with a Keplerian orbit by a stellar object of ${\sim}0.30M_{\odot}$, while the motions within 60 AU do not follow any Keplerian orbit at all. This makes it difficult to lead a reliable estimation of the mass of L328-IRS. Nonetheless, our ALMA observations were useful enough to well constrain the inclination angle of the outflow cavity of L328-IRS as ${\sim}66^{\circ}$ degree, enabling us to better determine the mass accretion rate of ${\sim}8.9{\times}10^{-7}M_{\odot}yr-1$.From assumptions that the internal luminosity of L328-IRS is mostly due to this mass accretion process in the disk, or that L328-IRS has mostly accumulated the mass through this constant accretion rate during its outflow activity, its mass was estimated to be ${\sim}0.012-0.023M_{\odot}$, suggesting L328-IRS to be a substellar object. However, we leave our identification of L328-IRS as a proto-brown dwarf to be tentative because of various uncertainties especially regarding the mass accretion rate.

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Numerical study of oxygen transport characteristics in lead-bismuth eutectic for gas-phase oxygen control

  • Wang, Chenglong;Zhang, Yan;Zhang, Dalin;Lan, Zhike;Tian, Wenxi;Su, Guanghui;Qiu, Suizheng
    • Nuclear Engineering and Technology
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    • 제53권7호
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    • pp.2221-2228
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    • 2021
  • One-dimensional oxygen transport relation is indispensable to study the oxygen distribution in the LBE-cooled system with an oxygen control device. In this paper, a numerical research is carried out to study the oxygen transport characteristics in a gas-phase oxygen control device, including the static case and dynamic case. The model of static oxygen control is based on the two-phase VOF model and the results agree well with the theoretical expectation. The model of dynamic oxygen control is simplified and the gas-liquid interface is treated as a free surface boundary with a constant oxygen concentration. The influences of the inlet and interface oxygen concentration, mass flow rate, temperature, and the inlet pipe location on the mass transfer characteristics are discussed. Based on the results, an oxygen mass transport relation considering the temperature dependence and velocity dependence separately is obtained. The relation can be used in a one-dimensional system analysis code to predict the oxygen provided by the oxygen control device, which is an important part of the integral oxygen mass transfer models.

Development of a Nutritional Supplement Certified Reference Material for Elemental Analysis

  • Lee, Jong Wha;Heo, Sung Woo;Kim, Hwijin;Lim, Youngran;Lee, Kyoung-Seok;Yim, Yong-Hyeon
    • Mass Spectrometry Letters
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    • 제9권4호
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    • pp.105-109
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    • 2018
  • A certified reference material (CRM) for the analysis of inorganic nutrients in nutritional supplements has been developed. Accurate mass fractions of chromium (Cr), iron (Fe), copper (Cu), and zinc (Zn) were determined by isotope dilution inductively coupled plasma mass spectrometry (ID ICP/MS). The measurement results were used to assign certified values for the CRM, which were metrologically traceable to the definitions of the measurement units in the International System of Units (SI). Production of a candidate reference material (RM) and the certification processes are summarized. Each nutrient in the CRM showed good homogeneity, which was estimated using relative standard deviations of the measurement results of twelve bottles in a batch. This CRM is expected to be an important reference to improve reliability and comparability of nutrient analyses in nutritional supplements and related samples in analytical laboratories.

Fast GPU Computation of the Mass Properties of a General Shape and its Application to Buoyancy Simulation

  • Kim, Jin-Wook;Kim, Soo-Jae;Ko, Hee-Dong;Terzopoulos, Demetri
    • 한국HCI학회:학술대회논문집
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    • 한국HCI학회 2007년도 학술대회 3부
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    • pp.326-333
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    • 2007
  • To simulate solid dynamics,a we must com-pute the mass, the center of mass, and the products of inertia about the axes of the body of interest. These mass property computations must be continuously re-peated for certain simulations with rigid bodies or as the shape of the body changes. We introduce a GPU-friendly algorithm to approximate the mass properties for an arbitrarily shaped body. Our algorithm converts the necessary volume integrals into surface integrals on a projected plane. It then maps the plane into a frame-buffer in order to perform the surface integrals rapidly on the GPU. To deal with non-convex shapes, we use a depth-peeling algorithm. Our approach is image-based; hence, it is not restricted by the mathematical or geometric representation of the body, which means that it can efficiently compute the mass properties of any object that can be rendered on the graphics hardware. We compare the speed and accuracy of our algorithm with an analytic algorithm, and demonstrate it in a hydrostatic buoyancy simulation for real-time applications, such as interactive games.

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Simulation Study to Improve Ion Transmission Efficiency in Mass Spectrometry with a Dual Ion Funnel Ion Source

  • Baek, Sun Jong;Kim, Seung Yong;Kim, Taeman;Kim, Hyun Sik
    • Mass Spectrometry Letters
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    • 제4권4호
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    • pp.91-94
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    • 2013
  • We performed computer simulations to improve transmission efficiencies of a dual ion funnel system implemented on an FT-ICR MS. We found that the low m/z range from 50 to 150 could be significantly improved by operating the two ion funnels at different RF amplitudes. These new operational conditions could be applied to analyze metabolome samples, which require high sensitivity in the m/z range from 50 to 1,000.

Differential Protein Quantitation in Mouse Neuronal Cell Lines using Amine-Reactive Isobaric Tagging Reagents with Tandem Mass Spectrometry

  • Cho, Kun;Park, Gun-Wook;Kim, Jin-Young;Lee, Sang-Kwang;Oh, Han-Bin;Yoo, Jong-Shin
    • Mass Spectrometry Letters
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    • 제1권1호
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    • pp.25-28
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    • 2010
  • The high-throughput identification and accurate quantification of proteins are essential strategies for exploring cellular functions and processes in quantitative proteomics. Stable isotope tagging is a key technique in quantitative proteomic research, accompanied by automated tandem mass spectrometry. For the differential proteome analysis of mouse neuronal cell lines, we used a multiplexed isobaric tagging method, in which a four-plex set of amine-reactive isobaric tags are available for peptide derivatization. Using the four-plex set of isobaric tag for relative and absolute quantitation (iTRAQ) reagents, we analyzed the differential proteome in several stroke time pathways (0, 4, and 8 h) after the mouse neuronal cells have been stressed using a glutamate oxidant. In order to obtain a list of the differentially expressed proteins, we selected those proteins which had apparently changed significantly during the stress test. With 95% of the peptides showing only a small variation in quantity before and after the test, we obtained a list of eight up-regulated and four down-regulated proteins for the stroke time pathways. To validate the iTRAQ approach, we studied the use of oxidant stresses for mouse neuronal cell samples that have shown differential proteome in several stroke time pathways (0, 4, and 8 h). Results suggest that histone H1 might be the key protein in the oxidative injury caused by glutamate-induced cytotoxicity in HT22 cells.