• Title/Summary/Keyword: pH influence

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Quasiclassical Trajectory Calculations for the Reaction Ne + H2+ → NeH+ + H

  • Wang, Yuliang;Tian, Baoguo;Qu, Liangsheng;Chen, Juna;Li, Hui
    • Bulletin of the Korean Chemical Society
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    • v.32 no.12
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    • pp.4210-4214
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    • 2011
  • Quasiclassical trajectory (QCT) calculations of Ne + ${H_2}^+$ reaction have been carried out on the adiabatic potential energy surface of the ground state $1^2$ A'. The reaction probability of the title reaction for J = 0 has been calculated, and the QCT result is consistent with the previous quantum mechanical wave packet result. Quasiclassical trajectory calculations of the four polarization-dependent differential cross sections have been carried out in the center of mass (CM) frame. The P(${\theta}_r$), P(${\phi}_r$) and P(${\theta}_r$, ${\phi}_r$) distributions, the k-k'-j' correlation and the angular distribution of product rotational vectors are presented in the form of polar plots. Due to the well in $1^2$ A' PES, the reagent vibrational excitation has greater influence on the polarization of the product rotational angular momentum vectors j' than the collision energy.

담수에서의 안정적인 포말분리를 위한 포말생성 영향 인자

  • Sin, Jeong-Sik;Lee, Ju-Hwa;Seo, Geun-Hak
    • 한국생물공학회:학술대회논문집
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    • 2003.04a
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    • pp.331-333
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    • 2003
  • The foam height was increased with the increase of protein concentration in the bulk solution and the decrease of the pore size. And it was increased at higher superficial air velocities and leveled off at beyond 0.84 cm/sec. It was the highest in the region of strong acid and foam height was recovered at pH 7. The influence of salts, such as NaCl, $NaHCO_3$, promoted to form.

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The Influence of Coexisting Material on the Photocatalytic Removal of Humic Acid (광촉매를 이용한 Humic Acid 광부해시 공존물질이 광분해에 미치는 영향)

  • Ryu, Seong Pil;Hyeon, Gyeong Ja;O, Yun Geun
    • Journal of Environmental Science International
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    • v.13 no.3
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    • pp.279-288
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    • 2004
  • This study aimed at improving the $TiO_2$ photocatalytic degradation of HA. A set of tests was first conducted in the dark to study the adsorption of HA at different coexisting material concentration. Adsorption rate increased with adding cation ion but decreased with adding bicarbonate ion. The photodegradation of HA in the presence of UV irradiation was investigated as a function of different experimental condition: initial concentration of HA, $TiO_2$ weight, pH, air flow rate and coexisting material. It was increased either at low pH or by adding cation ion. The increase of cation strength in aqueous solution could provide a favorable condition for adsorption of HA on the $TiO_2$ surface and therefore enhance the photodegradation rate. It was found that bicarbonate ions slowed down the degradation rate by scavening the hydroxyl radicals.

Influence of recycling time on stability of slurry and removal rate for silicon wafer polishing (Recycle 시간에 따른 실리콘 연마용 슬러리 입자 및 연마 속도)

  • Choi, Eun-Suck;Bae, So-Ik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.59-60
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    • 2006
  • The slurry stability and removal rate during recycling of slurry in silicon wafer polishing was studied. Average abrasive size of slurry was not changed with recycling time, however, large particles appeared as recycling time increased. Large particles were related foreign substances from pad or abraded silicon flakes during polishing. The removal rate as well as pH of slurry was decreased as recycling time increased. It suggests that the consumption of OH ions during recycling is the main cause of decrease of removal rate. Therefore, it is important to control pH of slurry to obtain optimum removal rate during polishing.

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Adsorption Behavior of Environmental Hormone Bisphenol A onto Mesoporous Silicon Dioxide

  • Fan, Xianghong;Tu, Bing;Ma, Hongmei;Wang, Xuefen
    • Bulletin of the Korean Chemical Society
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    • v.32 no.8
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    • pp.2560-2564
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    • 2011
  • Mesoporous silicon dioxide (meso-$SiO_2$) was prepared using cetyltrimethylammonium bromide as the structure-directing reagent and tetraethyl orthosicate as the silicon source. The influence of pH value on the adsorption behavior of bisphenol A (BPA) was investigated. The adsorption capacity of BPA onto meso-$SiO_2$ increases slightly with pH value from 2 to 6, and then gradually decreases as further improving pH value. The effect of temperature was also studied, and the adsorption capacity of BPA gradually declines with increasing temperature. The adsorption kinetics and thermodynamics of BPA were examined. It is found that the adsorption of BPA onto meso-$SiO_2$ is in good agreement with Langmuir adsorption model. The rate constant of adsorption is $5.17{\times}10^{-3}g\;mg^{-1}\;min^{-1}$, and the maximum adsorption capacity is as high as 353.4 $mg\;g^{-1}$ at 20 $^{\circ}C$.

The Effects of Chlorination on the Friction Properties of SBR (염소화 반응조건이 SBR의 표면마찰 특성에 미치는 영향)

  • Park, Cha-Cheol;Kim, Ho-Jung
    • Fashion & Textile Research Journal
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    • v.10 no.1
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    • pp.101-105
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    • 2008
  • This study was concerned with the influence of reaction conditions on the surface friction properties of Syrene-Butadiene Rubber(SBR) sheet when it was chlorinated by chemical treatment method using the sodium hypochlorite and sulfuric acid. The results of this study were as follows. SEM photographs of chlorinated SBR surface showed uneven etching caused by the chlorination. In the FTIR spectra, the intensity of C=C peak of SBR was decreased with increasing the concentration of sodium hypochlorite. Otherwise there was no trace of C=C peak in spectrum of SBR treated with 5 wt% NaOCl with pH 0.1 for 90 seconds. EDX spectra showed that relative content of chlorine of SBR was increased with increasing the amount of sodium hypochlorite, and also affected with pH condition of acid solution. Friction angle and friction coefficient of SBR were influenced with concentration of sodium hypochlorite, but were not with pH condition of acid solution.

Synthesis and Physicochemical Studies on a Novel Cephalosporin, DWC-751 (신규 세파로스포린 항생제 DWC-751 합성과 물성연구)

  • 김명구;안상근;최영기;문치장;오세한;성무제;윤길중;신종만;김학형
    • Biomolecules & Therapeutics
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    • v.1 no.1
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    • pp.103-108
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    • 1993
  • The synthesis and physicochemical properties of a novel cephalosporin, DWC-751 are described. DWC -751, (6R , 7R)-7-[ (Z)-2-(2-aminothiazol-4-yl)-2- methoxyiminoacetamido]-3-[(1-methylbenzotriazol-3-ium) methyl]-ceph-3-em-4-carboxylate monosulfate($IV_{\alpha}$) was conveniently obtained by the conversion of compound (IV) into the crystalline monosulfate. Adjusting pH 4.8-5.2 in aqeous solution of the crude crystalline, compound(IV) in the form of a crystalline pentahydrate was prepared with a high degree of purity. The influence of the various organic and inorganic acids on the solubility of compoud(IV) and its salts, was examined. Particularly, the solubility of DWC-751 was 92 mg/mι at pH 1.7 and 233 mg/mι at pH 3.0. DWC-751 showed a broad antimicrobial spectrum against gram-positive and negative bacteria.

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Soil Environment's Impact on the Growth of Pinus thunbergii by Season in Urban Forests (도시림의 계절별 토양환경이 곰솔의 생육에 미치는 영향)

  • Kim, Seok-Kyu
    • Journal of Environmental Impact Assessment
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    • v.20 no.4
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    • pp.455-464
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    • 2011
  • The purpose of this study is to clarify correlations between soil environments and the growth of trees in forests and thereon analyze effects of seasonal changes in such environments on such growth. To determine seasonal factors of soil affecting the Tree Vitality of Pinus thunbergii, first of all, the study designated the Tree Vitality as a dependent variable and soil hardness, moisture, pH, K, Na, Mg and Ca as independent variables. Then the study performed Pearson's coefficient analysis. To clarify what soil factors influence the seasonal growth of Pinus thunbergii multiple regression analysis is carried out, and findings are as follow; the growth of Pinus thunbergii was basically influenced by pH, followed by soil hardness in spring, K, followed by moisture in summer, and by soil hardness in winter. However, no soil factors affected the vitality at the significance level of 5% for t.

A study of corrosion of welded bridge steel SWS400 in the acid-rain environment (산성비 분위기에서 교량용 강재 SWS400의 용접부 부식에 관한 연구)

  • 정원석;김정구;이병훈
    • Journal of Welding and Joining
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    • v.15 no.5
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    • pp.124-133
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    • 1997
  • Corrosion behavior of welded SWS400 steel used for bridges was studied in a range of the acid-rain environment using immersion, potentiodynamic polartization, polarization resistance, and galvanic corrosion tests. The SWS400 steel exhibited active corrosion behavior in the range of acid-rain environment, i.e. no passivation. As the results of immersion corrosion test, Tafel extrapolation method, and polarization resistance measurement, the average corrosion rats of the steels were 0.31-0.72 mm/year in the pH of 4-5, and 0.17 mm/yera in the pH 6, respectively. The steel showed a resistance to corrosion in the pH 6. The observed active behavior of SWS400 steel in chloride-containing environment indicated that the chloride ions exerts a detrimental influence on the formation of passive films. Galvanic corrosion was observed between the weld and the base metals because the weld is anodic to the base metal.

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Influence of Propofol, Isoflurane and Enflurance on Levels of Serum Interleukin-8 and Interleukin-10 in Cancer Patients

  • Liu, Tie-Cheng
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.16
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    • pp.6703-6707
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    • 2014
  • Objective: To observe the influence of propofol, isoflurane and enflurance on interleukin-8 (IL-8) and IL-10 levels in cancer patients. Methods: Ninety cancer patients with selective operation from March 2011 to May 2014 were randomly divided into group A (34 cases), group B (28 cases) and group C (28 cases). Intramuscular injections of scopine hydrochloride and phenobarbital sodium were routinely conducted to 3 groups. After general anesthesia was induced, tracheal intubations were given. During the maintenance of anesthesia, 0.5~1.0 mg/kg propofol was intravenously injected to group A discontinuously, while continuous suctions of isoflurane and enflurance were subsequently performed to group B and C correspondingly. Clinical outcomes, postoperative complications as well as serum IL-8 and IL-10 levels before operation (T0), at the time of skin incision (T1), 3 h after the beginning of the operation (T2) and 24 h (T3) and 72 h (T4) after the operation were observed among 3 groups. Results: Operations in all groups were successfully completed. The rates of surgery associated complications were 8.82% (3/34), 7.14% (2/28) and 7.14% (2/28) in group A, B and C, respectively, and there were no significant differences (P>0.05). Serum IL-8 and IL-10 levels increased gradually from the beginning of the operation and reached the peak at T3, and were evidently higher at each time point than at T0 (P<0.01). At T1, serum IL-8 and IL-10 levels had no significant differences among 3 groups (P>0.05), but the differences were significant at T2, T3 and T4 (P<0.05). Moreover, correlation analysis suggested that serum IL-8 level was in positive relation with IL-10 level (r=0.952, P<0.01). Conclusions: Propofol, which is better in inhibiting serum IL-8 secretion and improving IL-10 secretion than isoflurane and enflurance, can be regarded as a preferable anesthetic agent in inhibiting traumatic inflammatory responses.