• Title/Summary/Keyword: Concentration profiles

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Vertical Profiles of CO2 Concentrations and CO2 Storage in Temperate Forest in Korea (한국 활엽수림의 이산화탄소 농도의 연직구조와 저류항)

  • Thakuri, Bindu Malla;Kang, Minseok;Chun, Jung Hwa;Kim, Joon
    • Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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    • 2013.11a
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    • pp.23-24
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    • 2013
  • Micrometeorological fluxes measured over a tall forest in a complex terrain are difficult to interpret. $CO_2$ storage often makes significant contributions to net ecosystem exchange of $CO_2$ (NEE) in early morning and during nighttime due to calm and stable conditions. We measured the above-canopy $CO_2$ flux along with its concentration profiles at eight levels within and above the canopy to evaluate $CO_2$ storage term. Our question is whether or not the $CO_2$ storage term can be estimated accurately from a single level measurement of $CO_2$ concentration in a complex terrain. Our objectives are (1) to document vertical profiles of $CO_2$ concentration and (2) to compare the diurnal and seasonal variations of $CO_2$ storages estimated from single and multi-level $CO_2$ concentration data. Seasonally averaged Diurnal variations of $CO_2$ concentration ranged from 398 to 455 ppm near the forest floor at 0.1 m whereas they ranged from 364 to 395 ppm at 40 m in the atmosphere. The diurnal variation of vertical profiles of $CO_2$ concentration shows very interesting features with season. At all eight levels, diurnal variation of $CO_2$ concentration showed little change in winter. In spring, the diurnal variations of $CO_2$ concentration at 8 levels showed three distinct groups of layers with height: the first layer: 0.1m (near surface), second layer: 1.0 m and 4.0m (below canopy) and the third layer: 7.4m to 40.7 m (near canopy and above). In summer, these three groups of layers were further separated with larger variations whereas such distinction became smaller in fall. The diurnal variation of $CO_2$ concentration in the first three layers near surface always showed higher concentration with larger variability. Typically, $CO_2$ concentration showed peaks in early morning and in the evening. After the evening peak, $CO_2$ concentration gradually increased except for those near the surface (i.e., 0.1, 1.0 and 4.0 m) where the concentrations actually decreased. We suspect that this could be attributed to the drainage flow of $CO_2$ along the hill slope from the headwater to downstream, which is not taken into account for net ecosystem $CO_2$ exchange. In comparison to the results of other studies, the distinct and different vertical structures of $CO_2$ concentrations observed at our site may be due to complex terrain and weak turbulent mixing under calm conditions at the site. The annual mean of diurnal variation of $CO_2$ storage flux from single level ranged from -0.6 to $0.9{\mu}mol\;m^{-2}s^{-1}$ and from multi-level from -1.2 to $1.0{\mu}\;{\mu}mol\;m^{-2}s^{-1}$. When compared against the results from the multi-level concentrations, the storage flux estimated from a single-level concentration was generally adequate except for specific hours near sunrise and sunset. Further details and their implication will be discussed in the presentation.

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Classification of Ellerman bombs

  • Kwak, Hannah;Chae, Jongchul
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.87.1-87.1
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    • 2013
  • Ellerman bombs(EB) are small-scale bright features observed best in the wings of H alpha line. We used the Fast Imaging Solar Spectrograph(FISS) with the 1.6m New Solar Telescope at Big Bear Solar Observatory, in order to investigate characteristics of each EB. We analyzed H alpha line profiles of EBs, and classified EBs by their contrast profiles. To analyse characteristics of EBs, we applied power-law fitting ($C={\alpha}{\Delta}{\lambda}^{-n}$) to the EB contrast profiles. The amplitude ${\alpha}$ is a measure of the strength of an EB event (or the amount of released energy), and the power-law index n is a measure of spatial concentration of energy in the higher layers of the solar atmosphere. With the two parameters, we classified EBs into a few groups. We try to understand the physical properties of each group.

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Soot Size and Concentration Measurements in a Laminar Diffusion Flame Using a Lignt Scattering/Extinction Technique (광산란 소멸법을 이용한 층류확산화염내에 매연입자의 크기 및 농도 측정)

  • 하영철;김상수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.9
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    • pp.1796-1804
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    • 1992
  • Profiles of soot volume fraction, average diameter and particle number density have been measured using a light scattering and extinction technique in a coannular propane diffusion flame at atmosperic pressure. Temperature profiles were also obtained using a thermocouple technique. Measurements show that soot is first observed to form low in the flame in an annular region inside the main reaction zone. At higher locations this annular region widen until entire flame is observed to contain particles. Soot volume fraction and particle diameter profiles peak some 1mm on the fuel side of peak temperature and increase with height to oxidation region. Number density of the flame core drop steeply from formation region to growth region and relatively invariant to some height and decay out at flame tip.

Calculation of Suspended Sediment Flux from ADP (ADP를 이용한 부유사 이동량의 산출)

  • 오병철;추용식;정병순
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.14 no.3
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    • pp.222-231
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    • 2002
  • The ADP is an advanced piece of oceanographic equipment that measures water speed and direction profiles from the acoustic Doppler principle. In recent years, the strength of the acoustic backscatter obtained from ADP has been used to measure vertically suspended sediment concentration(SSC) profiles. In this study, an ADP was installed in coastal waters near Yumsan, on the west coast of Korea, and flow and sediment data were gathered simultaneously. SSC concentrations were calculated from the acoustic backscatter strengths adjusted by using calibrated acoustic coefficients. The observed SSC profiles were compared with analytical solutions and showed good agreement. Simultaneously, the suspended material fluxes were analyzed in detail. ADP was very useful for measuring the vertically distributed suspended sediment concentrations and flow velocity profiles.

A Study of Concentration Profiles in Amorphous Silicon by Phosphorus Doping and Ion Implantation (비정질 실리콘에서 인의 도핑과 이온주입에 따른 농도분포에 대한 연구)

  • 정원채
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.12 no.1
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    • pp.18-26
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    • 1999
  • In this study, the undoped amorphous layers and phosphorus doped amorphous layers are fabricated using LPCVD at 531$^{\circ}C$ with SiH$_4$ gas or at same temperature with PH$_3$ gas during deposition, respectively. The thickness of deposited amorphous layer from this experiments was 5000 ${\AA}$. In this experiments, undoped amorphous layers are deposited with SiH$_4$and Si$_2$H$\_$6/ gas in a low pressure reactor using LPCVD. These amorphous layers can be doped for poly-silicon by phosphorus ion implantation. The experiments of this study are carried out by phosphorus ion implantation with energy 40 keV into P doped and undoped amorphous silicon layers. The distribution of phosphorus profiles are measured by SIMS(Cameca 6f). Recoiling effects and two dimensional profiles are also explained by comparisions of experimental and simulated data. Finally range moments of SIMS profiles are calculated and compared with simulation results.

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Assessment of Biochemical Profiles in Premenopausal and Postmenopausal Women with Breast Cancer

  • Yadav, Naval Kishor;Poudel, Bibek;Thanpari, C.;Koner, Bidhan Chandra
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.7
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    • pp.3385-3388
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    • 2012
  • Objective: The study was conducted to assess biochemical profiles in premenopausal and postmenopausal women having breast cancer. Materials and Methods: A hospital based case control study was carried out at Manipal Teaching Hospital (MTH), Pokhara, Nepal. The analysed variables were age, metabolic profile including total cholesterol, triglycerides, HDL-C, LDL-C, blood sugar, insulin concentration, C-peptide, HbA1c and selenium. Descriptive statistics and testing of hypothesis were used for the analysis using EPI INFO and SPSS 16 software. Results: In premenopausal women, significant differences were noted for total cholesterol (P value <0.001), triglycerides (P value 0.002), HbA1c level (P value <0.001), insulin concentration (P value 0.030), C-peptide concentration (P value 0.001), and selenium (P value <0.001) between cases and controls. Insignificant results were found for HDL-C (P value 0.749), LDL-C (P value 0.933), blood sugar (P value 0.59) and BMI (P value 0.746). Similarly, significant difference in total cholesterol (P value <0.001), triglycerides (P value 0.001), LDL-C (P value <0.001), HDL-C (P value 0.025), blood sugar (P value <0.001), insulin concentration (P value <0.001), c-peptide concentration (P value <0.001), HbA1c level (P value <0.001) and selenium (P value <0.001) were observed for postmenopausal patients and controls. Conclusions: Assessing metabolic changes and their management may be important for control of breast cancer and increased survival.

Relation between Vitamin A and $\beta$-Carotene Intakes and Serum Total Carotenoids Levels in Smoking College Students (흡연대학새의 비타민 A와 $\beta$-Carotene 섭취량 및 혈청 총 Carotenoids 수준과이 관계)

  • 강명희;박정아
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.28 no.2
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    • pp.492-500
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    • 1999
  • The aim of this study was to assess the association between total vitamin A, retinol and carotene intakes and serum concentration of total carotenoids in Korean male smokers and nonsmokers. Food frequency and nutrient intakes of 64 healthy college students were estimated by the 24 hour recall method and food frequency questionnaire and analyzed by smoking status. Serum total cartenoids and lipid profiles were measured in 28 smokers and 36 nonsmokers. The mean total vitamin A, retinol and carotene intakes of smokers were not significantly different from nonsmokers. However, carotene intakes of the smokers who have smoked more than 5 packyears were significantly lower than those of nonsmokers. Smokers consumed green yellow leafy vegetables more often(P=0.005) and fresh fruits less often(P=0.017) than nonsmokers. The serum total carotenoids of smokers consuming the same amount of retinol and carotene as nonsmokers, 1.79 g/ml, were 17% lower than nonsmokers, 2.15 g/ml(P<0.05). The lipid profiles including total cholesterol, LDL cholesterol, VLDL cholesterol and triglycerides of smokers were not significantly different from nonsmokers, however, the concentration of HDL cholesterol of smokers were significantly higher than that of nonsmokers. The serum carotenoids concentration was positively associated with fruit consumption frequency in smokers, and also was positively associated with green yellow leafy vegetable consumption frequency in non smokers. There were no correlations between dietary and serum carotenoids for smokers as well as nonsmokers. It was concluded that smoking could be inversely related to the serum concentration of carotenoids at constant carotene intakes and smokers might require more carotene to reach the same concentration comparable to nonsmokers.

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Development of Novel Technique for Determining the Oxygen Tracer Diffusion Coefficients in Oxides I - Measurements of the Time Profiles of $^{18}O_2$ Concentration in the Ambient Gas by Raman Spectroscopy - (산화물에서의 산소추적자확산계수를 결정하는 새로운 방법의 개발 I- 라만분광법에 의한 분위기가스 중의 시간에 따른 $^{18}O_2$ 농도변화 측정 -)

  • 김병국;하마구찌히로오;박순자
    • Journal of the Korean Ceramic Society
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    • v.31 no.11
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    • pp.1369-1377
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    • 1994
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A Study on the FE Analysis of Butt Welding (맞대기 용접부의 유한요소해석)

  • 최병일;구병춘
    • Proceedings of the KWS Conference
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    • 2003.11a
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    • pp.200-203
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    • 2003
  • The purpose of this paper is to investigate the influence of weld bead profiles on stress concentration factors (K$\sub$t/). We evaluated K$\sub$t/ by varying three parameters such as toe radii, flank angles and bead heights. The three parameters have similar effects on K$\sub$t/.

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Numerical Study on the Change of PM10 Profile by Asian dust

  • Cho, Chang-Bum;Kim, Yoo-Keun;Lee, Yong-Seob;Bang, So-Young
    • Journal of Environmental Science International
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    • v.16 no.5
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    • pp.533-539
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    • 2007
  • The research was conducted to simulate and interpret the change of $PM_{10}$ profile by Asian dust using the CALPUFF modeling system for the period April 6 through 18, 2001. The results, which are represented a daily variation of $PM_{10}$ concentration before and after Asian dust, was located between a minimum concentration of $50{\mu}g/m^3$ and a maximum concentration of $100{\mu}g/m^3$, Most concentration peaks in the $PM_{10}$ profile were shown within a level below 500 m and had a pattern that rapidly increased up the peak and decreased after the peak to 1000 m. Even though the shapes of the vertical profile during Asian dust days were similar to non-Asian dust days, no rapid change vertically was observed. In particular, the vertical profile on 1200 LST and 1800 LST was noticeably shifted to the higher concentrations, which means $PM_{10}$ in the atmosphere was changed into a vertically and horizontally heterogeneous form under the Asian dust event. Finally, it is con-firmed that the simulation result from CALPUFF might schematically sketched atmospheric $PM_{10}$ profiles and their change by Asian dust throughout the comparison with profiles of aerosol extinction coefficients, which were acquired from Lidar measurement at KGAWO.