• Title/Summary/Keyword: Chemical phenomena

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Effect of Lactic Acid Bacteria and Temperature on Kimchi Fermentation (I) (젖산균과 온도가 김치발효에 미치는 영향(I))

  • Cho, Young;Rhee, Hei-Soo
    • Korean journal of food and cookery science
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    • v.7 no.1
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    • pp.15-25
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    • 1991
  • The effects of lactic acid bacteria on the chemical and microbial changes of fermented kimchi at various temperatures were studied. Kimchi was homogenized and was sterilized by ultra violet, then Lactobacillus plantarum, Leuconostoc mesenteroides, Pediococcus acidilactici, Lactobacillus brevis and the mixture of there bacteria inoculated on sterilized kimchi, respectively. The measurement of pH and total acidity, quantitative analysis of volatile organic acids and nonvolatile organic acids by gas chromatography were investigated while inoculated kimchi were fermented at $30^{\circ}C$, $21^{\circ}C$, $14^{\circ}C$ and $7^{\circ}C$. Sample I (original kimchi homogenate), Sample III (inoculated with Leuconostoc mesenteroides) and Sample Ⅵ (inoculated with mixed lactic acid bacteria) were alike in that changes of pH and total acidity and especially, these phenomena were prominent at $14^{\circ}C$. Formic, acetic and heptenoic acid as volatile organic acid were detected by GC, and these acids formed mainly by Leuconostoc mesenteroides and lactobacillus brevis. Sample III was more higher content than other samples at $14^{\circ}C$. As nonvolatile organic acid, lactic acid in all samples, citric acid in sample III at $21^{\circ}C$and $14^{\circ}C$, succinic acid in sample I at $30^{\circ}C$, $21^{\circ}C$, $14^{\circ}C$ and sample V at $30^{\circ}C$ were detected by GC.

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Mono-layer Compositional Analysis of Surface of Mineral Grains by Time-of-Flight Secondary-Ion Mass Spectrometry (TOF-SIMS) (TOF-SIMS를 이용한 광물 표면의 단층조직 분석 연구)

  • Kong Bong Sung;Chryssoulis Stephen;Kim Joo Young
    • Journal of the Mineralogical Society of Korea
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    • v.18 no.2
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    • pp.127-134
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    • 2005
  • Although the bulk composition of materials is one of the major considerations in extractive metallurgy and environmental science, surface composition and topography control surface reactivity, and consequently play a major role in determining metallurgical phenomena and pollution by heavy metals and organics. An understanding of interaction mechanisms of different chemical species at the mineral surface in an aqueous media is very important in natural environment and metallurgical processing. X-ray photoelectron spectroscopy (XPS) has been used as an ex-situ analytical technique, but the material to be analyzed can be any size from $100\;{\mu}m$ up to about 1 cm. It can also measure mixed solids powders, but it is impossible to ascertain the original source of resulting x-ray signals where they were emitted from, since it radiates and scans the macro sample surface area. The study demonstrated the ability of TOF-SIMS to detect individual organic species on the surfaces of mineral particles from plant samples and showed that the TOF-SIMS techniques provides an excellent tool for establishing the surface compositions of mineral grains and relative concentrations of chemicals on mineral species.

Relationship between Seed Size and Seed Vigor in Soybean. (콩의 종실크기와 종자활성 간의 관계)

  • 박금룡;최원열;정동희;김석동
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.38 no.2
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    • pp.139-150
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    • 1993
  • This experiment was carried out to investigate the difference of seed vigor according to seed size, and the physiological aspects and physico-chemical phenomena related with seed vigor in soybean cultivars. Portion of seed coat and radicle to entire seed was much higher in cultivars with small seed than with large. Seed coat rate ranged 7.9% to 9.9%, and radicle 2.5% to 3.3% in small seed group, Whereas in large seed, seed coat rate did 5.5-6.4% and radicle, 1.5 to 2.1%. After accelerated aging treatment, there are significant difference in germination ability between seed size. The germination rate after aging ranged 47 to 80% in cultivars with small seed, but in large seed, only 14 to 24%. After seed was carried out dehydration in incubator at 25 after soaking for 6 hours, the moisture content of seed in drying for 12 hour was 25.5% in small seed, while it was 51% in large seed. Electrical conductivity, leaching soluble nitrogen and sugar content were higher in large seed cultivars. Besides, cotyledon damage after soaking was occurred frequently in large seed cultivars, and seed vigor within same cultivars was higher in small seed than large.

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When Dose Losses of Maternal Lymphocytes Response to Trophoblast Antigen or Alloantigen Occur in Women with a History of Recurrent Spontaneous Abortion? (반복유산을 경험한 환자에서 임신중 태반항원과 동종항원에 노출된 모체 림프구면역반응은 언제부터 소실되나?)

  • Choi, Bum-Chae;Hill, Joseph A.
    • Clinical and Experimental Reproductive Medicine
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    • v.25 no.2
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    • pp.115-122
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    • 1998
  • The maintenance of a viable pregnancy has long been viewed as an immunological paradox. The deveolping embryo and trophoblast are immunologically foreign to the maternal immune system due to their maternally inherited genes products and tissue-specific differentiation antigens (Hill & Anderson, 1988). Therefore, speculation has arisen that spontaneous abortion may be caused by impaired maternal immune tolerance to the semiallogenic conceptus (Hill, 1990). Loss of recall antigen has been reported in immunosuppressed transplant recipients and is associated with graft survival (Muluk et al., 1991; Schulik et al., 1994). Progesterone $(10^{-5}M)$ has immunosuppressive capabilities (Szekeres-Bartho et al., 1985). Previous study showed that fertile women, but not women with unexplained recurrent abortion (URA), lose their immune response to recall antigens when pregnant (Bermas & Hill, 1997). Therefore, we hypothesized that immunosuppressive doses of progesterone may affect proliferative response of lymphocytes to trophoblast antigen and alloantigen. Proliferative responses using $^3H$-thymidine ($^3H$-TdR) incorporation of peripheral blood mononuclear cells (PBMCs) to the irradiated allogeneic periperal blood mononuclear cells as alloantigen, trophoblast extract and Flu as recall antigen, and PHA as mitogen were serially checked in 9 women who had experienced unexplained recurrent miscarriage. Progesterone vaginal suppositories (100mg b.i.d; Utrogestan, Organon) beginning 3 days after ovulation were given to 9 women with unexplained RSA who had prior evidence of Th1 immunity to trophoblast. We checked proliferation responses to conception cycle before and after progesterone supplementation once a week through the first 7 weeks of pregnancy. All patients of alloantigen and PHA had a positive proliferation response that occmed in the baseline phase. But 4 out of 9 patients (44.4%) of trophoblast antigen and Flu antigen had a positive proliferative response. The suppression of proliferation response to each antigen were started after proliferative phase and during pregnancy cycles. Our data demonstrated that since in vivo progesterone treated PBMCs suppressed more T-lymphocyte activation and $^3H$-TdR incorporation compare to PBMCs, which are not influenced by progesterone. This data suggested that it might be influenced by immunosuppressive effect of progesterone. In conclusion, progesterone may play an important immunological role in regulating local immune response in the fetal-placental unit. Furthermore, in the 9 women given progesterone during a conception cycle, Only two (22%) repeat pregnancy losses occured in these 9 women despite loss of antigen responsiveness (one chemical pregnancy loss and one loss at 8 weeks of growth which was karyotyped as a Trisomy 4). These finding suggested that pregnancy loss due to fetal aneuploidy is not associated with immunological phenomena.

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Reduction of Autochthonous Organics in Masan Bay using a Simple Box Model (마산만의 자생 유기물 저감을 위한 단순 박스모델의 적용)

  • Hong, Sok-Jin;Lee, Won-Chan;Yoon, Sang-Pil;Park, Sung-Eun;Cho, Yoon-Sik;Kwon, Jung-No;Kim, Dong-Myung
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.13 no.2 s.29
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    • pp.111-118
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    • 2007
  • Simple box budgets models are useful tools to understand the phenomena of natural system and to provide an insight into the complex processes including physical, chemical and biological processes occurring in natural system. Budgets of fresh water, salt and nutrients were estimated in order to clarify the characteristics of seasonal material cycle in the Masan Bay. Outflow volume of freshwater into system was approximately $307.4\times10^3\sim1,210\times10^3\;m^3/day$. Inflow masses of DIP and DIN were approximately $410.8\sim795.7\;kg/day$ and $4081.4\sim6525.3\;kg/day$, respectively. DIN is expected to accumulate in the system. The removal of nutrients from bottom sediments will contribute to the reduction of 21.0% of COD concentration in the system.

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Advanced Wastewater Treatment on ship's sewage with new MARPOL73/78 ANNEX IV (MARPOL73/78 ANNEX IV의 개정발효에 따른 선박 오수의 고도처리)

  • Park, Sang-Ho;Lim, Jae-Dong;Park, Sung-Jeng;Kim, In-Soo
    • Proceedings of KOSOMES biannual meeting
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    • 2007.05a
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    • pp.91-96
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    • 2007
  • Lab scale experimental study was carried out for SBR process, to investigate the effects of influent ship sewage organic compound removal and Bacillus sp. state on design parameters. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. More than 95% of chemical oxygen demand(COD) were removed. In addition, about 97% of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged 93%. The performance load of SBR process was shown to be $0.095kg{\cdot}TOC/m^3{\cdot}day$. The pH was decreased from 8.1 to 7.0 within 30 min and increased to 7.3 at the end of anoxic stage, and these phenomena were explained. The sludge produced in the SBR process is characterized by low generation rate (about $0.36kg{\cdot}MLSS/kg{\cdot}TOC$) and excellent settleability. The number of Bacillus sp. in the SBR was 24.2%, indicating that Bacillus sp. was a predominant species in the reactor.

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A study on synthesis of $Li_{x}Mn_{2}O_{4}$ for asecondary battery with various $MnO_{2}$ structure (다양한 $MnO_{2}$ 구조에 따른 2차전지용 $Li_{x}Mn_{2}O_{4}$ 합성에 관한 연구)

  • 김익진;이영훈;이종호;이재한;장동환;이경희;고영신
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.6 no.4
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    • pp.600-608
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    • 1996
  • Specific structural properties of Li intercalation reaction into the spinel relatedmanganese dioxide, $Li_{x}Mn_{2}O_{4}(0.2{\leq}x{\leq}2.0)$, are investigated by X-ray diffractional and electrochemical studies of Li/1M $LiClO_{4}$-propylene carbonate solution/$Li_{x}Mn_{2}O_{4}$ cell. The effect of the chemical composition and the reaction temperature on electrochemical parameter of $Li_{x}Mn_{2}O_{4}$ are studied by the phenomena of phase-transition, analysis of crystal lattice, fine structure, and thermal analysis. Treatment of the spinel $Li_{x}Mn_{2}O_{4}$ with aqueous acid was found to result in conversiton of $Li_{x}Mn_{2}O_{4}$ to nearly pure $MnO_{2}$, as evidenced by a reduction in the lattice constant $a_{c}$ from 8.255 to $8.031\;{\AA}$. At a composition range of $0.2{\leq}x{\leq}0.6$ in $Li_{x}Mn_{2}O_{4}$ the reduction proceeded in a homogeneous phase, which was characterized by a constant voltage of 3.9~3.7 V together with a lattice constant of $8.255\;{\AA}$.

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Flow behavior characteristics according to superficial gas velocity of NiO/MoO3/MoS2 (NiO/MoO3/MoS2의 공탑속도에 따른 유동화 특성)

  • Lee, Jae-Rang;Hasolli, Naim;Jeon, Seong-Min;Lee, Kang-San;Lee, Kwan-Young;Kim, Kwang-Deuk;Park, Young-Ok
    • Particle and aerosol research
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    • v.13 no.2
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    • pp.79-85
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    • 2017
  • This study identified the loss of minimum fluidization velocity and pressure in accordance with the superficial velocity of $NiO/MoO_3/MoS_2$, a rare metallic oxide and high value-added material in the lab-scale fluidized bed reactor (L=0.25 m, D=0.05 m). The average pressure loss in L/D 1, 2, and 3 of $NiO/MoO_3/MoS_2$ within the scope of superficial gas velocity between 0.07 and 0.45 m/s based on the L/D 1, 2, and 3 of the specimen was shown to be 290~1952 Pa at decreasing flux and 253~1925 Pa at increasing flux. The comparison between the theoretical value proposed by Wen and the test data showed a difference between 0.021~0.36 magnification. Based on these results, this study was able to determine the operation conditions where rare metallic oxides could be applied in real phenomena.

Advanced Wastewater Treatment using Sequencing Batch Reactor on ship's sewage (연속 회분식 공정(SBR)을 이용한 선박 오·폐수의 고도처리)

  • Park Sang-Ho;Kim In-Soo
    • Journal of Navigation and Port Research
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    • v.29 no.5 s.101
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    • pp.475-480
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    • 2005
  • Lab scale experimental study was carried out for SBR process, to investigate the effects of influent ship sewage organic compound removal and Bacillus sp. state on design parameters. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. More than $92.0\%$ of chemical oxygen demand(COD) were removed. In addition, about $84.0\%$ of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged $93\%$. The performance load of SBR process was shown to be $0.095kg{\cdot}TOC/m3{\cdot}day$. The pH was decreased from 8.1 to 7.0 within 30 min and increased to 7.3 at the end of anoxic stage, and these phenomena were explained. The sludge produced in the SBR process is characterized by low generation rate (about $0.36kg{\cdot}MLSS/kg{\cdot}TOC$) and excellent settleability. The number of Bacillus sp. in the SBR was $24.2\%$, indicating that Bacillus sp. was a predominant species in the reactor.

Design Scheme to Develop Integrated Remediation Technology: Case Study of Integration of Soil Flushing and Pneumatic Fracturing for Metal Contaminated Soil (복합복원기술 개발을 위한 설계안 : 중금속 오염토양을 위한 토양세척과 토양파쇄의 통합 사례 연구)

  • Chung, Doug-Young;Yang, Jae-E.
    • Korean Journal of Soil Science and Fertilizer
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    • v.39 no.1
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    • pp.29-37
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    • 2006
  • In remediation of the contaminated soil, it requires to select at least more than two remediation technologies depending on the fate and transport phenomena through complicated reactions in soil matrix. Therefore, methodologies related to develop the integrated remediation technology were reviewed for agricultural soils contaminated with heavy metals. Pneumatic fracturing is necessary to implement deficiency because soil washing is not effective to remove heavy metals in the subsurface soil. But it needs to evaluate the characteristics such as essential data and factors of designated technology in order to effectively apply them in the site. In the remediation site, the important soil physical and chemical factors to be considered are hydrology, porosity, soil texture and structure, types and concentrations of the contaminants, and fate and its transport properties. However, the integrated technology can be restrictive by advective flux in the area which remediation is highly effective although both soil washing and pneumatic fracturing were applied simultaneously in the site. Therefore, we need to understand flow pathways of the target contaminants in the subsurface soils, that includes kinetic desorption and flux, predictive simulation modeling, and complicated reaction in heterogenous soil.