• Title/Summary/Keyword: Mass changes

Search Result 2,181, Processing Time 0.031 seconds

A Social Scientific Study on changes in Mass media Environments Caused by Multimedia Developments (멀티미디어 발달로 인한 매체환경 변화의 사회.과학적 고찰)

  • 김정숙;서경석
    • Proceedings of the Korea Multimedia Society Conference
    • /
    • 2000.11a
    • /
    • pp.580-583
    • /
    • 2000
  • 최근 멀티미디어 기술의 변화는 무서운 속도로 진행되고 있다. 디지털 혁명의 물결은 처음에는 미디어 기술의 변화를 불러 일으켰다. 그리고 차차 사회의 전 영역으로 확대되어 사회제도와 무형의 의식까지를 변화시키는, 마치 도미노 현상을 연상시키고 있다 이미 인터넷을 통한 광고는 외면할 수 없는 시장으로 자리를 굳혔으며, 이러한 매체의 획기적인 전환과 대체는 광고의 성격과 형식, 기법에 이르기까지 전면적인 수정과 적응을 요구하고 있다. 때문에 본 논문에서는 거대한 매체 환경 변화의 맥락 가운데서 광고가 어떻게 변화해 가는지에 대해 조망하고, 그러한 변화의 와중에서 광고 관련 분야가 준비해야 할 것은 무엇인지, 어떻게 준비해야 할 것인지를 제안하였다.

  • PDF

Prediction of Temperature, Moisture Content and Quality Changes in Stored Bulk Rough Rice (시뮬레이션에 의한 산물(散物) 저장(貯藏) 벼의 온도(溫度), 함수율(含水率) 및 품질변화(品質變化)의 예측(豫測))

  • Keum, D.H.;Kim, J.Y.
    • Journal of Biosystems Engineering
    • /
    • v.16 no.1
    • /
    • pp.49-59
    • /
    • 1991
  • A numerical model was developed to predict grain temperature, moisture content, and drymatter loss of rough rice in a grain storage bin. This model simulated conduction, natural convection, and mass transfer occuring inside a storage bin. The results obtained from the study were as follows. 1. The predicticted results agreed well with the measured results. 2. Rough rice could be store safely for one year in Suweon, Dajeon, and Jingu area. 3. Aeration of 5-day was required to control grain temperature and moisture content rise early in Jun and July, respectively.

  • PDF

Elastic Moduli and Dissolution Rates of Resorbable Na2O-MgO-P2O5 Bioglasses (Na2O-MgO-P2O5 생체 유리의 탄성계수와 용해도)

  • ;T.D.Taylor
    • Journal of the Korean Ceramic Society
    • /
    • v.26 no.6
    • /
    • pp.850-854
    • /
    • 1989
  • The elastic moduli and dissolution rates of 15 glasses with different mole ratios of sodium-magnasium-phosphate as potential non-toxic biomaterials were investigated. In this study, a 3-pint bending test, sonic resonance technique, and theoretical calculation were used to evaluate the modulus of elasticity. The dissolution rates at 37$^{\circ}C$(human body temperature) were determined by the measurement of mass changes in each sample for 24 weeks.

  • PDF

On increasing the homogeneity of the properties of epitaxial layers grown from the gas phase, taking into account natural convection and changes in the rate of chemical interaction between materials

  • Pankratov, E.L.
    • Advances in materials Research
    • /
    • v.9 no.2
    • /
    • pp.155-170
    • /
    • 2020
  • In this paper, using the recently introduced analytical approach for the analysis of mass and heat transfer during film growth in reactors for epitaxy from the gas phase, these processes are analyzed taking into account natural convection and the possibility of changing the rate of chemical interaction between reagents. As a result of the analysis, the conditions under which the homogeneity of the grown epitaxial layers increases with a change in the values of the parameters of the growth process are formulated.

Determination of Isotopic Ratios for Ca in Inductively Coupled Plasma Mass Spectrometry (ICPMS) by Removing Water Related Molecules

  • 박용남;S. R. Koirtyohann
    • Bulletin of the Korean Chemical Society
    • /
    • v.18 no.11
    • /
    • pp.1172-1175
    • /
    • 1997
  • Calcium isotopic ratios are precisely measured by removing isobaric interferences originated from water in the plasma. Liquid Ar cryogenic trap combined with membrane desolvator could eliminate backgrounds at m/z 42 and 44. Slow drift of ICP-MS is corrected by the frequent running of the standards. It is found necessary to separate Ca from the sample matrix using Ca oxalate precipitation technique. Currently, the RSD is 0.5-1.0% for 2 minutes of measurement but is expected to be improved if the measurement time is increased. The technique was applied to 42Ca enriched baby fecal samples and successfully determined 42Ca/44Ca ratio changes.

Seasonal Variation in Fatty Acid Composition in Female Pen Shell (Atrina Pectinata)

  • Baik Sung-Hyun;Kim Kang-Jeon;Choo Jong-Jae;Choe Sun-Nam;Chung Ee-Yung;Park Kwan Ha
    • Fisheries and Aquatic Sciences
    • /
    • v.4 no.4
    • /
    • pp.261-264
    • /
    • 2001
  • Seasonal variation in fatty acid profiles was examined in the visceral mass and the posterior adductor muscle of the female pen shell, Atrina pectinata. Total percentages of saturated fatty acids were similar between the two organs, and there was not a prominent seasonal change in both tissues. While the percentages of highly unsaturated fatty acids (HUFAs) in the visceral mass were higher than those in the posterior adductor muscle, monounsaturated fatty acids (MUFAs) were high in the posterior adductor muscle. HUFA contents, especially in $20: 5\omega3$, $22: 5\omega3$ and $22: 6\omega3$, markedly decreased in September in the visceral mass, and this decrease was associated with a corresponding total MUFAs in the same organ. A similar pattern of change in September was noted in the posterior adductor muscle MUFAs and HUFAs. These results indicate that $20:\omega3$ and $22:\omega3$ HUFA changes in the visceral mass and posterior adductor muscle reflect the reproductive stages in pen shell.

  • PDF

Geochemical Evidence for Spatial Paleoproductivity Variations the Northwest Pacific (Shikoku Basin) during the Last Glacial Maximum

  • Hyun, Sang-Min;Ahagon, Naogazu;Saito, Saneatu;Ikehara, Minoru;Oba, TadamichI;Taira, Asahiko
    • Journal of the korean society of oceanography
    • /
    • v.31 no.4
    • /
    • pp.207-216
    • /
    • 1996
  • A geochemical study of three piston cores (ST.4, ST.6 and ST.20) taken from the Northwest Pacific (eastern edge of Shikoku Basin) provides information about changes in surface water paleoproductivity and sedimentation during the last 127 kys. Paleoproductivity variations were estimated on the basis of total organic carbon content and carbonate mass accumulation rate. The paleoproductivity based on total organic carbon shows significant spatial variations between glacial and interglacial periods. During the last glacial maximum (LGM) paleoproductivity increased about 1.5 times with deglaciation decrease compared with those of the Holocene at inner side of the Shikoku Basin (ST.4 and ST.6). On the other hand, paleoproductivity at outer side of Shikoku Basin (ST.20) indicating not distinctive increase but deglaciation increase. The C/N ratios fall below 10 for cores ST.4 and ST.6, but C/N ratios between 100 ka and 80 ka in ST.20 which show around 10 or larger values suggest a predominance of marine organic carbon with some admixture of terrigenous materials. The carbonate mass accumulation rate of three cores show different patterns of calcareous record with respect to organic carbon based paleoproductivity variation. In the inner side of Shikoku Basin (ST.4 and ST.6) the carbonate mass accumulation rate decreased during last glacial maximum, and significant increase of carbonate mass accumulation rate is recognized at outer side of Shikoku Basin (ST.20). Thus, this set of data reveals that spatial paleoproductivity variations between inner and outer side of Shikoku Basin during the glacial and interglacial periods.

  • PDF

Rapid and Quantitative Analysis of Clavulanic Acid Production by the Combination of Pyrolysis Mass Spectrometry and Artificial Neural Network

  • Kang, Sung-Gyun;Lee, Dae-Hoon;Ward, Alan-C.;Lee, Kye-Joon
    • Journal of Microbiology and Biotechnology
    • /
    • v.8 no.5
    • /
    • pp.523-530
    • /
    • 1998
  • Rapid and quantitative analysis of physiological change and clavulanic acid production was studied by the combination of pyrolysis mass spectrometry (PyMS) and artificial neural network (ANN) in Streptomyces clavuligerus. Firstly, the continuous culture studies were carried out to get the physiological background and PyMS samples. Clavulanic acid production was inversely related to growth rate: Mycelium growth and $q_{cal}$ were optimum at 0.1 $h^{-1}\; and \;0.025 h^{-1}$ respectively. Changes in specific nutrient uptake rates ($q_{gly}$ and $q_{amn}$) also affected clavulanic acid production since clavulanic acid production appeared to be stimulated by the limitation of carbon and nitrogen. Fermentation broth containing mycelium taken from continuous cultures was analyzed by PyMS, and the PyMS spectra were analyzed with multivariate statistics. PCCV plots revealed that samples harvested under the same culture condition were clustered together but samples from different culture conditions formed separate clusters. To deconvolute the pyrolysis mass spectra so as to obtain quantitative information on the concentration of clavulanic acid, ANN was trained on Py MS data using a radial basis function classifier. The results showed that the physiological stages with different growth rate were successfully differentiated and it was possible to monitor the clavulanic acid production precisely and rapidly.

  • PDF

Body Mass Index, Anthropometric Factors, and Food and Nutrient Intakes of Korean Middle-Aged Males by Year : Based on 2001~2011 Korea National Health and Nutrition Examination Survey (KNHANES) (한국 중년 남성의 연도별 체질량지수, 신체계측치, 식품 및 영양소 섭취량 변화 : 국민건강영양조사 결과(2001~2011))

  • Choi, Soon-Nam;Jho, Kwang-Hyun;Chung, Nam-Yong
    • Journal of the Korean Dietetic Association
    • /
    • v.22 no.2
    • /
    • pp.88-105
    • /
    • 2016
  • This study investigated anthropometric and biochemical characteristics, food and nutrient intakes, and changes in body mass index (BMI) of Korean middle age men (40~49 yrs). Data on BMI, anthropometric (height, weight, waist circumference, body mass index, blood pressure), and biochemical (total cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride, hemoglobin, GOT, GPT) characteristics, food and nutrients intakes, nutrient density, and index of nutrient quality were obtained from the Fifth Korea National Health and Nutrition Examination Survey (KNHANES, 2001, 2005, 2011). Subjects were divided into three groups by year. Weight, BMI, and hemoglobin increased significantly by year. All anthropometric factors except height showed a positive relation with BMI by year. Consumption of barley, chinese noodle, confections, soybean milk, egg, ice cream, pizza, fried foods, banana, coffee, and raw rice wine increased significantly by year. Intake ratios of nutrients except water and fiber were over 100% of KDRI generally. INQ according to intakes of protein, calcium, phosphorus, iron, vitamin A, thiamine, riboflavin, and niacin per 1,000 kcal increased significantly by year. Distribution of BMI status of subjects showed a significant difference by exercise. The findings of the present study show that BMI of subjects increased by year, and intakes of all nutrients except calcium and riboflavin showed aspects of overnutrition by year. Intakes of fruits decreased while intakes of raw rice wine and coffee increased by year. Therefore, practical and systematic nutrition programs are required to maintain optimum BMI and appropriate intakes of nutrients to maintain a desirable lifestyle and improve dietary life.

The effect of simulated acid rain on microbial community structure in decomposing leaf litter

  • Cha, Sangsub;Lim, Sung-Min;Amirasheba, Bahitkul;Shim, Jae-Kuk
    • Journal of Ecology and Environment
    • /
    • v.36 no.4
    • /
    • pp.223-233
    • /
    • 2013
  • Acid deposition is one of the most serious environmental problems in ecosystems. The present study surveyed the effects of simulated acid rain on leaf litter mass loss and microbial community in the decomposing leaf litter of Sorbus anifolia in a microcosm at $23^{\circ}C$ and 40% humidity. Microbial biomass was measured by substrate-induced respiration (SIR) and phospholipid fatty acids (PLFAs), and the microbial community structures were determined by composition of PLFAs at each interval of decomposition in litter sample and at each pH treatment. The microbial biomass showed peaks at mid-stage of decomposition, decreasing at the late stage. The leaf litter mass loss of S. anifolia decreased with decreasing pH during early and mid-decomposition stages; however the mass loss becomes similar between pH treatments at late-decomposition stage. The acidification remarkably lowers the microbial biomass of bacteria and fungi; however, microbial diversity was unchanged between pH treatments at each stage of litter decomposition. With changes of decomposition stage and pH treatment there were considerable differences in replacement and compensation of microbial species. Fungi/bacteria ratio was considerably changed by pH treatment. The PLFA profile showed significantly larger fungi/bacteria ratio at pH 5 than pH 3 at the early stage of decomposition, and the difference becomes smaller at the later decomposition stage. At low pH, pH 3 and pH 4, the fungi/bacteria ratios were stable according to the litter decomposition stages. Simulated acid rain caused decreases of 10Me17:0, 16:1${\omega}$7c, 18:1${\omega}$7, 15:0, but increase of 24:0. In addition, litter mass loss showed significant positive correlation with microbial biomass measured by SIR and PLFA on the decomposing leaf litter.