• 한국식품과학회지
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• 제22권3호
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• pp.343-349
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• 1990

pH를 달리한 수용액 및 농도를 달리한 염류수용액에서 들깨종실의 단백질과 phytate의 용해도를 측정하여 단백질로부터 phytate를 제거할 수 있는 조건을 검토하였다. 들깨종실단백질의 용해도는 pH4.0에서 가장 낮은 9.5%로 등전점을 보였고, 그보다 산성 또는 알칼리성쪽으로 갈수록 증가되었다. 반면에 phytate의 용해도는 pH5.0에서 가장 높았으며 그보다 산성 또는 알칼리성쪽으로 갈수록 감소되었다. NaCl 수용액을 처리하였을 때 단백질의 용해도는 pH $3.0{\sim}4.0$ 범위에서 가장 낮았고 pH 6.0 이상에서는 현저히 증가되었다. Phytate의 용해도는 pH$2.0{\sim}5.0$ 범위에서는 약 90%내외로 높았으나 pH6.0 이상에서는 급격히 감소되었다. $Na_2SO_3$ 수용액처리에서는 단백질 용해도가 $pH2.0{\sim}3.0$ 범위에서 가장 낮았고 phytate의 용해도는 $pH5.0{\sim}6.0$에서 최대치를 보였고, 3%의 경우는 전 pH 구간에 걸쳐서 낮았으나 5%와 7%에서는 전 구간에서 높았다. $CaCl_2$ 수용액처리에서는 단백질 용해도가 3% 수용액에서는 전 pH 구간에서 낮았으나 5%와 7%에서는 $pH5.0{\sim}10.0$에서 높은 값을 보였으며 phytate의 용해도는 $pH2.0{\sim}3.0$ 사이에서 최대값을 나타내고 pH4.0이상에서는 급격히 감소하였다. 이상의 결과에서 3% NaCl 용액을 사용하여 pH9.0에서 단백질을 추출하고 pH4.0에서 침전시켰을 때 단백질 수율이 좋고 phytate 잔존량이 가장 적어, 저(低)phytate 분리단백질을 만드는 가장 좋은 조건이었다..

• Bulletin of the Korean Chemical Society
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• 제18권2호
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• pp.218-221
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• 1997

When phenylation of styrene was carried out in the presence of Pd(OAc)2 and PPh3 in benzene, trans-stilbene was obtained in good yield (566%) with high selectivity (98%) under mild condition (55 ℃, 50 psi O2, 20 h). Since trans-stilbene could be produced not only from benzene but also from phenyl group of PPh3 by migration of its phenyl group to Pd, the competitiveness of benzene and the migratory aptitude of aryl group of triarylphosphine toward styrene has been investigated with various phosphines (PR3: P(p-C6H4CH3)3, P(p-C6H4OCH3)3, P(p-C6H4F)3, P(p-C6H4Cl)3, P(C6H5)3, P(C6H11)3, P(OC4H9n)3, P(CH2C6H5)3 and P(C6F5)3). The yield and selectivity toward trans-stilbene are increased as the basicity of the phosphines increases. The composition of arylated olefin from arylphosphine, in turn, increases as the electronegativity of the substituent on the aryl group of arylphosphines increases.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.382-386
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• 1998

The objectives of this study are to reveal relationship between tree physiology and spectral reflectance on effects of artificial acid rain and to obtain basic data on optimal wave length for forest of LRC sensor on KOMPSAT-2. Three pH levels of artificial acid rain - control, pH4.5 and pH3.0 - were applied to Pinus and Quercus species. Three types of the acid rain were spraied at the amount of 500m1 in every two days. Spectral reflectance data was collected once in a month by using GER 1500 (350~2500nm) or Ll 1800(300~1100nm) Spectroradiometer. The data was measured three times in a pH level. The results of this study are as follows; in April, the spectral reflectance of Pinus species was high in order at the level of pH3.0, control and pH4.5; in May, control, pH3.0 and pH4.5; in June, control, pH4.5 and pH3.0. That of Quercus species was high in the order of control, pH4.5 and pH3.0 in May; in June, control, pH3.0 and pH4.5, especially, within infrared wave length range, control, pH4.5 and ph3.0.

• 생물환경조절학회지
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• 제10권1호
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• pp.50-54
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• 2001

잎상추 수경재배시 배양액 내 NO$_3$-N와 NH$_4$-N 비율 및 pH 조절이 엽중 nitrate 함량에 미치는 효과를 구명하였다. NO$_3$-/NH$_4$$^{+}$의 비율 처리는 12:1, 10:3, 8:5이었으며, 8:5 처리구에 pH를 자동적으로 조절해준 처리구조 설정하였다. pH의 변화는 12:1 처리구에서는 실험기간 동안 계속적으로 상승하는 경향을 보였고, NH$_4$$^{+}$의 비율이 높을수록 pH가 상당한 저하하다가 낮은 수준에서 유지되었다. NH$_4$$^{+}$의 비율이 가장 높았던 8:5에 pH를 자동적으로 조절해준 처리구에서는 5.5-6.5 사이의 안정적인 수준으로 pH를 유지하였다. 엽중 nitrate 함량은 전반적으로 12:1 처리구에서는 점점 감소하는 경향을 보였으나, 12:1과 8:5에 pH를 조절해준 처리구에서는 비슷한 양상으로 수확시마다 증가하는 경향을 보였다. 즉, NH$_4$$^{+}$의 비율을 높이고 배양액의 pH를 조절하는 것이 생육 및 엽중 nitrate 함량에 가장 좋은 것으로 나타났다

• 대한전자공학회논문지
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• 제19권6호
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• pp.52-54
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• 1982

p·Si-전해질 접합을 전해질로 6N H2SO4, 6N H2SO4(Ti3+), 6N H2SO4(Ti4+), 6N H2SO4(Ti4+/Ti3+)을 사용하여 만들었다. 이들 전해질중 6N H2SO4(Ti4-/Ti3+)을 사용할 때 p·Si 광음극이 안정하게 동학하며 높은 광전 감도를 가지고 있었다. p·Si-electrolyte junction are prepared by using p·Si photocatode in four different electrolytes such as 6N H2SO4, 6N H2SO4(Ti3+), 6N H2SO4(Ti4+), 6N H2SO4(Ti4+/Ti3+) respectively. Among those electrolytes 6N H2SO4(Ti4-/Ti3+) shows very good results, in which p·Si photocathode is stable.

• 환경위생공학
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• 제9권2호
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• pp.1-7
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• 1994

Rainwater was collected in Seoul area from January 1991 to December 1993 (over 3years) and by the analysis of the chemical components contained in rainwater, investigated the components that effect on rainwater pH Through the above studies the following conclusions were obtained. 1) Method for Averaging pH Volume weighted method is considered to be acceptable providing that precipitation is measured at the same time when the samples are taken, without precipitation data a simple averaging method should be the next choice. 2) Annual average rainwater pH was 4.98 in 1991, 4.80 in 1992, 4.67 in 1993, measurement range was 3.6-8.1. 3) In the relationship between rainwater pH and rainfall amounts rainwater pH for light rain(<15mm rainfall) was existent in the wide range(pH 4-7), but for heavy rain was corresponded to the annual average values. 4) Annual frequency of pH was Birrndat the frequency($\gamma $) between the density of the [$H^{+}$] and pH in the rainwater(over 3years ), $NO_{3}^{-}$ was excellent and the obtained results was 0.62 in 1992. Also In the correlation coefficient($\gamma $) according to the pH range $SO_{4}^{2-}, NO_{3}^{-}$, were 0.85 ,0.68 at 3.6 $Cl^-$ was 0.99(1993). At 4.1$NO_{3}^{-}(\gamma=0.48)$ in 1992, SO_4^{2-}($\gamma$=0.54), $NO_{3}^{-}(\gamma$=0.72), $Cl^- (\gamma$=0.49) in 1993. 6) pH values gradually increased with increase in $Ca^{2+}/SO_{4}^{2-}$.

• Restorative Dentistry and Endodontics
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• 제37권1호
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• pp.16-23
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• 2012

Objectives: Present study was undertaken to investigate the crystal growth onto synthetic hydroxyapatite (HA) seeds in pH 4.3 and pH 7.0 supersaturated solutions with different fluoride concentrations. Materials and Methods: 8 groups of pH 4.3 and 7.0 calcium phosphate supersaturated solutions were prepared with different fluoride concentrations (0, 1, 2 and 4 ppm). Calcium phosphate precipitates yield crystal growth onto the HA seed surface while solutions flow. For evaluation of crystallizing process, the changes of $Ca^{2+}$, $PO{_4}^{3-}$, $F^-$ concentrations of the inlet and outlet solutions were determined. The recovered solid samples were weighed to assess the amount of minerals precipitated, and finally determined their composition to deduce characteristics of crystals. Results: During the seeded crystal growth, there were significantly more consumption of $Ca^{2+}$, $PO{_4}^{3-}$, $F^-$ in pH 4.3 solutions than pH 7.0 (p < 0.05). As fluoride concentration increased in pH 4.3 solution, $Ca^{2+}$, $PO{_4}^{3-}$, $F^-$ consumption in experimental solutions, weight increment of HA seed, and fluoride ratio in crystallized samples were increased. There were significant differences among the groups (p < 0.05). But in pH 7.0 solution, these phenomena were not significant. In pH 7.0 solutions, analyses of crystallized samples showed higher Ca/P ratio in higher fluoride concentration. There were significant differences among the groups (p < 0.05). But in pH 4.3 solution, there were not significant differences in Ca/P ratio. Conclusions: Crystal growth in pH 4.3 solutions was superior to that in pH 7.0 solutions. In pH 4.3 solutions, crystal growth increased with showed in higher fluoride concentration up to 4 ppm.

• 한국결정학회지
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• 제15권1호
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• pp.35-39
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• 2004

Two new nickel vanadium borophosphate cluster compounds, $(NH_4)_{10}[Ni(H_2O)_5]_4[V_2P_2BO_{12}]_6{\cdot}nH_2O$ (1) and $(NH_4)_{3.5}(C_3H_{12}N_2)_{3.5}[Ni(H_2O)_6]_{1.25}{[Ni(H_2O)_5]_2[V_2P_2BO_{12}]_6{\cdot}nH_2O$ (2) have been synthesized and structurally characterized. Inter-diffusion methods were employed to prepare the compounds. The cluster anion $[(NH_4)\;{\supset}\;V_2P_2BO_{12}]_6$ is used as a building unit in the synthesis of new compounds containing $Ni(H_2O){^{2+}_5}$ in the presence of pyrazine and 1,3-diaminopropane. Compounds contain isolated cluster anions with general composition ${[Ni(H_2O)_5]_n[(NH_4)\;{\supset}\;V_2P_2BO_{12}]_6}^{-(17-2n)}$ (n = 2, 4). Crystal data: $(NH_4)_{10}[Ni(H_2O)_5]_4[V_2P_2BO_{12}]_6{\cdot}nH_2O$, monoclinic, space group C2/m (no. 12), a = 27.538(2) ${\AA}$, b = 20.366(2) ${\AA}$, c = 11.9614(9) ${\AA}$, ${\beta}$ = 112.131(1)$^{\circ}$, Z = 8; $(NH_4)_{3.5}(C_3H_{12}N_2)_b[Ni(H_2O)_6]_{3.5}{[Ni(H_2O)_5]_2[V_2P_2BO_{12}]_6{\cdot}nH_2O$, triclinic, space group P-1 (no. 2), a = 17.7668(9) ${\AA}$, b = 17.881(1) ${\AA}$, c = 20.668(1) ${\AA}$, ${\alpha}$ = 86.729(1)$^{\circ}$, ${\beta}$ \ 65.77(1)$^{\circ}$, ${\gamma}$ = 80.388(1)$^{\circ}$, Z = 2.

• The Korean Journal of Ecology
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• 제21권1호
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• pp.65-72
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• 1998

Various effects of simulated acid rain by $HNO_3$ and $H_2SO_4$ with pH 3.2, 4.2 and 5.6 were investigated in Melilotus suaveolens Ledeb, a biennial legume dominating the disturbed and poor soil vegetations. The nitric acid treatment of pH 3.2 resulted in 121% increase of the plant height compared to that of pH 5.6 during early growth, although 17% decrease was detected with the sulfuric acids. During 14 days of treatment, leaf biomass and chlorophyll content increased 168% and 133% with pH 3.2 nitric acid rain but decreased 20% and 38%, respectively, with sulfuric acid rain. Nitrogen content in various organs was also determined after 42 days of nitric acid treatment. It increased 480% and 387% by pH 3.2 and 4.2 in leaves, 212% and 214% in stems and 247% and 249% in roots. However, the same treatment with the sulfuric acid showed a considerable reduction in this content, indicating that the nitric acid was a nitrogen source. Nodule formation assayed revealed 15% decrease with pH 3.2 in contrast to 157% increase in pH 4.2, further suggesting an enhancement effect by the additional nitrogen source. Contrary to this, the nodule formation was reduced up to 43-71% by sulfuric acid rains. Specific nitrogen fixation activities of nodules estimated at pH 3.2, 4.2 and 5.6 nitric acid rain were 36.7, 42.8 and 47.3 ${\mu}mol\;C_2H_4{\cdot}g^{-1}\;fw\;nodule{\cdot}h^{-1}$, while those of sulfuric acid rain exhibited 1 nmol $C_2H_4{\cdot}plant^{-1}{\cdot}h^{-1}$ with pH 3.2, 177 with pH 4.2 and 179 with pH 5.6, yet it increased 2, 115 and 286 respectively corresponding to the three sulfuric acid concentrations. Further implications of the simulated acied rain were also discussed in the study.

• 식물병연구
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• 제16권1호
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• pp.81-85
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• 2010

산성비 수준의 고농도 수소이온 스트레스인 pH 5.6-4.0 처리는 애기장대 생장에 크게 해를 주지 않았으며 강산성인 pH 3.5 이하에서 수소이온 농도가 높아질수록 식물 뿌리 및 줄기의 생장이 위축되었으며 특히 뿌리가 줄기보다 더 민감하게 반응하였다. 엽록소 함량은 pH 5.6-4.0까지 pH가 낮아질수확 증가히였다. pH 4.0에서 내려갈수록 점진적으로 엽록소 함량이 감소되는 경향을 보였으며 카로티노이드도 엽록소와 같은 경향을 보였으나 pH 3.5에서 함량이 가장 높았다. 안토시아닌은 pH가 낮아질 수록 계속 증가하여 pH 3.0에서 가장 많이 축적되었으며 pH 2.5에서는 급격히 감소되었다. 스트레스 강도가 세어 질수록 엽록소 대비 식물체내 카혹티노이드 및 안토시아닌 함량이 증가한다는 것은 엽록소를 보호하기 위한 식물의 생리적 반응으로 여겨진다. 그러나 안토시아닌과 카로티노이드는 수소이온 농도에 따른 식물체내 함량의 변화가 상이하여서 고수소이온 스트레스에서 식물의 보호하는 기작이 다를 것으로 에상된다.