• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.6
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• pp.203-209
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• 2023

Cobalt sulfide nanocomposites were synthesized through a simple hydrothermal method as anode materials for sodium ion batteries (SIBs). In this work, a cobalt sulfide nanoparticle (CoS-NF) and a cobalt sulfide nanocomposite integrated with reduced graphene oxide (CoS@G-NC) were fabricated for electrochemical energy storage performance of battery. The as-prepared CoS@G-NC electrode exhibited reversible and stable cycle performance (62 % after 30 cycles at current density of 200 mA g^-1). The improved electrochemical property was attributed to the small grain growth and uniform distribution of cobalt sulfide during synthesis, which maximized the diffusion pathway for sodium ions and effectively suppressed the delamination and volume expansion of cobalt sulfide during the conversion reaction. The results provide promising anode materials for next-generation SIBs.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.6
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• pp.479-485
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• 2002

We have investigated the effects of various wafers cleaning on glass/Si bonding using 4 inch Pyrex glass wafers and 4 inch silicon wafers. The various wafer cleaning methods were examined; SPM(sulfuric-peroxide mixture, $H_2SO_4:H_2O_2$ = 4 : 1, $120^{\circ}C$), RCA(company name, $NH_4OH:H_2O_2:H_2O$ = 1 : 1 : 5, $80^{\circ}C$), and combinations of those. The best room temperature bonding result was achieved when wafers were cleaned by SPM followed by RCA cleaning. The minimum increase in surface roughness measured by AFM(atomic force microscope) confirmed such results. During successive heat treatments, the bonding strength was improved with increased annealing temperatures up to $400^{\circ}C$, but debonding was observed at $450^{\circ}C$. The difference in thermal expansion coefficients between glass and Si wafer led debonding. When annealed at fixed temperatures(300 and $400^{\circ}C$), bonding strength was enhanced until 28 hours, but then decreased for further anneal. To find the cause of decrease in bonding strength in excessively long annealing time, the ion distribution at Si surface was investigated using SIMS(secondary ion mass spectrometry). tons such as sodium, which had been existed only in glass before annealing, were found at Si surface for long annealed samples. Decrease in bonding strength can be caused by the diffused sodium ions to pass the glass/si interface. Therefore, maximum bonding strength can be achieved when the cleaning procedure and the ion concentrations at interface are optimized in glass/Si wafer direct bonding.

• Polymer(Korea)
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• v.25 no.5
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• pp.671-678
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• 2001

Sodium and zinc salts of poly(ethyaene-co-methacrylic acid) ionomers consist of three phases, i.e. ionic aggregates, amorphous, and crystalline phases. Dye molecules after soaked from the methanol solution are located near the amorphous phase or ionic aggregates within ionomer films. Depending on the location of the molecules in the ionomer film, they are under influence of dispersion forces (ethylene parts), polar forces (acid parts). and ionic dipole (ionic aggregates) interactions. The UV/Vis absorption peak of Nile Red under the dispersion force is found at near 500 nm, for the dye under the polar force effect 525 nm, and 550 and 610 nm for the dyes under $Na^+$ and $Zn^{2+}$ ionization effects, respectively. Since the divalent $Zn^{2+}$ ion has larger ionic dipole than the monovalent $Na^+$ ion, the larger red-shift of the absorption band due to the ionic dipole interaction is observed for $Zn^{2+}$ counter ion.

• Polymer(Korea)
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• v.34 no.2
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• pp.126-132
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• 2010

A cation-exchange nanofiber poly(vinylidene fluoride) (PVdF) membrane was prepared by a radiation-induced graft polymerization (RIGP) of sodium styrene sulfonate (NaSS) in the presence of the polymerizable access agents in methanol solution. The used polymerizable access agents include styrene, acrylic acid, and vinyl pyrrolidone. The anion-exchange nanofiber PVdF membrane was also prepared by RIGP of glycidyl methacrylate (GMA) and its subsequent chemical modification. The successful preparations of cation- and anion-exchange PVdF membranes were confirmed via SEM, XPS and thermal analysis. The content of the grafting yield, ion-exchange group, and water uptake was in the range of 30.0~32.3%, 2.81~3.01 mmol/g and 66.6~147%, respectively. The proton conductivity at 20$^{\circ}C$ was in the range of 0.020~0.053 S/cm. From the result, the prepared ionexchange PVdF membrane can be used as a separator in battery cells.

• Korean Journal of Pharmacognosy
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• v.12 no.1
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• pp.31-43
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• 1981

In order to determine the effect of Oryeongsan reputed to have diuretic action since Han Dynasty and possible synergetic action of Dianthi Semen, Polygonum avicularis Herba, Kochiae Fructus and Akebiae Lignum, herbs with similar reputation, when added to the above prescription, their decoction powders were solved into distilled water and injected into rabbits through the ear vein. Upon the treatment, the excretion of sodium, potassium and chloride ion together with urine volume was kinetically determined. At the same time the clearance of plasma creatinine and sodium ion was determined and the following results were obtained. Every experimental group demonstrated diuretic action, though feable, of relatively long duration. The diuretic mechanism in the case of Oryeongsan made up by mixing the seperate extracts of individual components and Oryeongsan(A) plus Dianthi Semen was found to be inhibitory effect of renal tubular reabsorption in contrast to the case of Oryeongsan(A) plus Polygonum avicularis Herba, Kochiae Fructus or Akebiae Lignum in which case the diuretic mechanism was found to be glomerular vascular dilatation. The urinary excretion of potassium ion was increased in the case of Oryeongsan(A) plus Dianthi Semen, Kochiae Fructus of Akebiae Lignum whereas in the other cases no similar change was registered. The diuretic action was most remarkable in the case of Oryeongsan(A) plus Polygonum avicularis Herba followed by Oryeongsan(A) plus Kochiae Fructus, Oryeongsan(A) plus Dianthi Semen, extract mixture of individual component of Oryeongsan, Oryeongsan(A) and Oryeongsan(A) plus Akebiae Lignum decreasing order. The duration of diuretic action was found to be 90 minutes in the case of Oryeongsan and mixture of individual component of Oryeongsan, and 60 minutes in the case of Oryeongsan(A) plus Dianthi Semen, Kochiae Fructus or Akebiae Lignum in contrast to the case of Oryeongsan(A) plus Polygonum avicularis Herba which lasted up to 120 minutes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.6
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• pp.492-498
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• 1984

We have reported the seasonal and portional variation in the composition of uronic acid of alginic acid from Ecklonia cava in the previous study. In the present paper, uronic acid block structure of alginic acid from Ecklonia cave was investigated, and some related properties such as viscosity, the dependence on temperature and substitution of metallic ion were also discussed. The proportion M block was highest amnog three blocks in both of frond and stipe. The average values of M and G block ratios were $51.6|%\;and\;32.3\%$ in the frond, whereas $45.7\%\;and\;38.6\%$ in the stipe, respectively. The proportions of alternating blocks in the frond and stipe were similar, and the values were $16.1\%$ in the frond and $15.6\%$ in the stipe. The viscosity of $1\%$ sodium alginate solution was almost inversely proportional to the M/G and/or M block ratio. Viscosities were marked maximum from summer to autumn and minimum winter to spring. In the value of lower M/G and M block ratio, the viscosity seemed to have a considerable dependence on temperature. The temperature dependence was more appearant in the alginic acid from the frond (M/G ratio, 0.95; M block, $54.2\%$) collected in July and the stipe (M/G ratio, 1.61; M block $47.6\%$) in April. The affinity with metallic ion appeared higher in order of $Pb^{2+}>Cu^{2+}>Co^{2+}>Zn^{2+}$. The amounts of metallic ion exchange of the $Pb^{2+},\;Cu^{2+},\;Co^{2+}\;and\;Zn^{2+}$ were ranged from 3.4. to 4.7, 2.5 to 3.2, 1.8 to 2.2 and 1.6 to 1.7 meq/(g. sodium alginate), respectively.

• Korean Journal of Microbiology
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• v.22 no.1
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• pp.57-66
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• 1984

Cells of Stigmatella aurantiace developed in the light on the medium containing calcium, barium, or lithium ion formed fruiting bodies without stalk. Fruiting body with stalk was formed on the medium containing calcium ion and GMP (GMP-medium) even under the dark condition. On the medium containing calcium and pheromone (pheromone-medium), most cells were developed only into the stalk in the light and into the sporangium in the dark. The number of aggregate formed on the medium containing calcium ion (Ca-medium) was more than that formed on the medium containing calcium, potassium, and sodium ions (CPS-medium). The number of aggregate formed on the GMP or pheromone-medium was less than that formed on the Ca-medium. Both pheromone and GMP reduced the time required for aggregate formation when cells were developed in the dark. Light stimulated cells to form more aggregates in short time when it was introduced into the Ca-, CPS-, GMP-, or pheromone-medium.

• Resources Recycling
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• v.2 no.2
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• pp.1-8
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• 1993

This study was carried out in order to define the effective collectors and the opitimum conditions for the removal of iron ion in waste water by flotation method. The results obtained in this study are summarized as follows. Fe(II) and Fe(III) were removed effectively at pH7 and 6 respectively by using sodium lauryl sulfate, an anionic collector. The anionic collector, aeropromotor 845, removed both Fe(II) and Fe(III) effectively in pH ranges of from 5 to 9. The cationic collector, trimetyl dodecyl ammonium chloride, removed both Fe(II) and Fe(III) effectively in pH ranges from 10 to 11 and from 4 to 10, respectively. Therefore, Fe(II) and Fe(III) could be effectively removed by forming the iron hydroxide precipitates by simple pH adjustment of the solutions above precipitation point of ferrous and ferric ion by flotation method. Then, the effective pH regulator and collector were NaOH and $Na_2CO_3$,aeropromotor 845 and trimetyl dodecyl ammonium chloride, respectively.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.401-409
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• 1996

The effect of temperature on the cmc of sodium N-lauroyl-N-methyl taurate was examined. The cmc values were found to be decreased initially but increased further with the increase of temperature. From the temperature dependence of cmc, various thermodynamic properties were calculated. The effects of various electrolytes on the cmc of sodium N-lauroyl-N-methyl-taurate were also examined. The free energy of hydrophobic bond formation and the degree of dissociation of the micelles were calculated from log cmc vs. log counter ion concentration plots. The ${\Delta}H_m$ values were decreased with increasing the temperature and changed their signs from plus to minus at $40^{\circ}C{\sim}50^{\circ}C$. The ${\Delta}G_m$ values were decreased with the increase of electrolyte concentration and temperature.

• Journal of the Korean Chemical Society
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• v.59 no.4
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• pp.271-279
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• 2015

The critical micelle concentration (CMC), the counter ion binding constant (B) and the aggregation number (N^* ) for the mixed micellization of sodium dodecanoate and sodium n-octanoate as two anionic surfactants have been investigated by means of electric conductivity and light scattering. As its experimental results are found to be deviated from ideal mixed model, thus two different kinds of regular solution models such as Rubingh and Motomura are used for interpreting our experimental data. The stability of the mixed micelles has been confirmed from the negative values of the standard Gibbs energy of mixed micellization ΔG^micel,0 over all compositions and the measured values of ΔG^micel,0 agreed with the theoretical ones within the experimental error.