• Korean Journal of Crystallography
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• v.16 no.1
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• pp.43-53
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• 2005

The dihydrido P-C-P pincer complex, $IrH_2{C_6H_3-2,6-(CH_2PBu_2^t)_2}$ (1), was successfully prepared from the reaction of the hydrochloride complex, $IrClH (C_6H_3-2,6-(CH_2PBu_2^t)_2}$, and super acid $(LiBEt_3H)$ under 1 atm of hydrogen in pentane solution at room temperature and followed by Heating at $130^{\circ}C$ in vacuo. Jensen recently found that the dihydrido P-C-P pincer complex 1 is a highly active homogeneous catalyst for the transfer dehydrogenation of alkanes with unusual longterm stability at temperatures as high as $200^{\circ}C$. The treatment of dihydrido complex 1 with nitrogen, water, carbon dioxide, and carbon monoxide in presence of tert-butylethylene (the) at room temperature in an appropriate solution gave the dinitrogen complex, $[Ir{C-6H_3-2,6-(CH_2PBu_2^t)_2}]_2({\mu}-N_2)$ (2), the hydrido hydroxyl complex, $IrH(OH){C_6H_3-2,6-(CH_2PBu_2^t)_2}$ (3), the carbon dioxide complex, $Ir({\eta}^2-CO_2) {C_6H_3-2,6-(CH_2PBu_2^t)_2}$ (including the bicarbonate complex, $IrH({\kappa}^2-O_2COH){C_6H_3-2,6-(CH_2PBu_2^t)_2}\;(4))$, and the carbonyl complex, $Ir(CO) {C_6H_3-2,6-(CH_2PBu_2^t)_2}\;(5)$ (including the carboxyl complex, $IrH(C(O)OH) {C_6H_3-2,6-(CH_2PBu_2^t)_2}\;(6))$, in good yield, respectively. These P-C-P iridium complexes were isolated and characterized by $^1H,\;^{13}C,\;^{31}P\; NMR$, and IR spectroscopy. In addition, the complexes (1-6) were characterized by a single crystal X-ray crystallography. These complexes account for these small molecules' inhibition of dehydrogenation of alkanes catalyzed by the dihydrido complex 1.

• Journal of the Korean Society for information Management
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• v.5 no.1
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• pp.53-78
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• 1988

The purpose of this study is to verify the factors determining core journals in a field based upon the results of the citation analysis of the journals in the field of Korean History(KH). In order to verify the determinant factors, dividing the articles of the KH journals into their novelty and author's seniority, the following hypotheses were established. Hypothesis 1: When a KH journal publishes more articles on prehistoric and ancient eras than others, the journal will have higher chance to be included in the core journals. Hypothesis 2: When a KH journal publishes more articles by senior researchers than others, the journal will have higher chance to be included in the core journals. To achieve the purpose, the cited articles found in the two sample journals, namely, Backsan Hakbo and Hanguksa Yongu were analysed during the past 20 years from 1962 to 1981. Applying the Hirst's Discipline Impact Factor method to the the study, Historical Science Impact Factor(HSIF) on the samples itself and the historical era dealt with in the articles and the seniority of the authors during every five-year period. Based upon thr present study to ver~fy the two hypotheses, the following conclusions have been reached. 1) Tht. most influencing sublect mattcr era or1 thix liSIF of the lo~lrual is arranged in prehistoric arid ancient, Koryo, Chosun, recent era, and the others by order of era. 2 ) Clial~g~~lg a fringe or semicore journal u~to a core j ~ u r n a l , very IISIF' 011 it> article e r a 1s grown up arrd prcllistoric a ~ ~ d ancierlt era:. are, s p c c ~ a l l ~ , incr.eased high relatively. Char~ging a core journal int:~ a fr~ngr or semicort. journal, t.very IISIF ti dropped and prel~istc~ric and ancieut taras arc, fallen sharp relatively. 3) The most irlflr~encin~ s~niority 011 the t1SII- of ihc journal I. the senior.., written or1 prehistoric and ancient eras. Above all, the senilir'b HSIF olr prehistoric anti anclent e r a s a r e most ~nfluencing the cliangi~rg of the core journal into the fringe ur bemicore. .i) flypothesis fl is no1 vcrif~ed i r t general. T l ~ e rt, lative connections bet wee^^ the senior's HSIF 011 each era and tht, ~ l ~ a l ~ g i t l g of the tort. ji1ur.tia1 arc \:er~fied in part hut r~ot in the wliole. 5) 'The reason why the 11SIF or1 prehistori~. arid ar~cic~nt e r a s is higl~er than others can be assumed becaltic the new <, xcavations a r r contit~ued actively i l l the prrsr.llt as to the relics arid remains or1 that eras. Accordingly, the HSIF' r i l l thr 11ew 3ubject matter l~ke arcl~acmlogy trends to grow up greatly. Bctween the senior's and juriior's JISIE', junior'.; is higl~er than s., nior's except ancient e r a . That reason can be assumed bccausr Iunlorb t r j to solve the ex~sting problems thr~urglr their ow11 new viewpoints and sights. So, i t should be studied whether the 11SlF on the artic1t.s of the new subject matters and viewpoirrts is influenced to the changing of the core jorlrnal or not.

• Journal of Life Science
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• v.28 no.1
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• pp.17-25
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• 2018

In this study, we examined the efficacy of the immune regulation of ${\beta}$-1,3/1,6-glucan and Lactobacillus plantarum LM1004 on atopic dermatitis models. The oral administration of ${\beta}$-1,3/1,6-glucan and L. plantarum LM1004 on mice significantly decreased the amount of scratching, leakage to evans blue, and concentrations of serum immunoglobulin E (IgE) and histamine compared with the atopic dermatitis - induced group. When atopic dermatitis was induced, the transcription factors (GATA-3, retinoic acid-related orphan receptor ${\gamma}$ T [$ROR{\gamma}T$]) and cytokines (interleukin-4 [IL-4], IL-17) of Th2 and Th17 cells were overexpressed at the transcriptional level, and they significantly decreased with oral administration of ${\beta}$-1,3/1,6-glucan and L. plantarum LM1004. In addition, ${\beta}$-1,3/1,6-glucan and L. plantarum LM1004 were shown to modulate the immune balance by increasing the expression of Th1 and Treg transcription (T-bet, forkhead box p3 [Foxp3]) and cytokines (interferon-${\gamma}$ [IFN-${\gamma}$], transforming growth factor-${\beta}$ [TGF-${\beta}$]). Galectin-9 and filaggrin were significantly lower in the atopic dermatitis - induced group and significantly higher in the ${\beta}$-1,3/1,6-glucan-treated group. In contrast, thymic stromal lymphopoietin (TSLP) was highest in the atopic dermatitis-induced group, while mice that were orally administered ${\beta}$-1,3/1,6-glucan and L. plantarum LM1004 showed similar TSLP levels to the control group. These results indicate that ${\beta}$-1,3/1,6-glucan and L. plantarum LM1004 have immunomodulatory effects and atopic dermatitis improvement effects in an animal model of atopic dermatitis. Therefore, it is expected that ${\beta}$-1,3/1,6-glucan and L. plantarum LM1004 can be used as natural materials in the treatment of atopic dermatitis.

• Journal of Environmental Science International
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• v.14 no.9
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• pp.889-896
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• 2005

The nanosized $TiO_2$ photocatalysts were prepared by the hydrolysis of $TiCl_4$ and calcined at different temperatures. The resulting materials were characterized by TGA, DSC, XRD, and TEM testing techniques. XRD, TEM, and BET measurements indicated that the particle size of $TiO_2$ was increased with rise of calcination temperature and surface area was decreased with rise of it. The prepared $TiO_2$ photocatalysts were used for the photocatalytic degradation of congo red. The effects of calcination temperature, $TiO_2$ loading, the initial concentration of congo red, and usage frequencies were investigated and the rate constants were determined by regressing the experimental data. Calcination is an effective treatment to increase the photo activity of nanosized $TiO_2$ photocatalysts resulting from the improvement of crystallinity. The optimum calcination temperature of the catalyst for the efficient degradation of congo red was found to be $400^{\cric}C$. The rate constant was decreased with increase in the initial concentration of congo red and increased with increase in the $TiO_2$ loading. In the case of $TiO_2$ photocatalysts, the photocatalytic activity wasn't greatly affected by the usage frequencies.

• Magazine of the Korea Concrete Institute
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• v.2 no.1
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• pp.79-90
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• 1990

The purpose of this paper is to study on the effect of cutting off tension bars in reinforced concrete beams. that is, the ultimate strength, the failure mode and thl} tension stress distribution through the span. To achieve this purpose, a full-scale frame and seven small scale model beams (five rectangular and two T-section beams) were tested. The four main model specimens and two speciml}ns without cutting off tension bars 1,'{ere analyzed as plane stmss element with package program ADINA. As a result of test and analysis, the shorter' distance bet ween the reaction point and the cutting off point, the higher the ultimate strength of a bl}am will be when other physical properties are equal.

• Journal of the Korean Ceramic Society
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• v.32 no.10
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• pp.1147-1161
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• 1995

When ceramic membrance was made from metal salt solution in place of metal akoxide solution, crack free and good adhesion to supporter was optimized for sol stability and good adhesion force. A starting sol was prepared from aluminum oxychloride aqueous solutjion in order to inhibit the grain growthof Al2O3 during heat treatment. The crack free dip coating can't be achieved in 1mol/ι zirconium oxychloride solution because of the high viscosity which interferes with the hydration copolymerization between Al3+ ion and Zr4+ ion. Thus Al2O3-ZrO2 sol stability and viscosity for dip coating was effective when 0.01 mol/ι zirconium oxychloride was added. The minimizing of crack and achieving better adhesion to the supporter wa obtained by microwave drying, surfactant addition and ultrasonic dip coating in wet atmosphere. The result seems to minimize the capillary force and improve the adhesive ability to supporter during the process. Where the average pore size of Al2O3-ZrO2 ultrafilter ceramic membrane measured 17 Å by the BET method and observed γ-Al2O3 phase with tetragonal zirconia after firing at 700℃.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.103-110
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• 2014

Sisal fiber, an agricultural resource abundantly available in china, has been used as raw material to prepare activated carbon with high surface area and huge pore volume by chemical activation with zinc chloride. The orthogonal test was designed to investigate the influence of zinc chloride concentration, impregnation ratio, activation temperature and activation time on preparation of activated carbon. Scanning electron micrograph, Thermo-gravimetric, $N_2$-adsorption isotherm, mathematical models such as t-plot, H-K equation, D-R equation and BJH methods were used to characterize the properties of the prepared carbons and the activation mechanism was discussed. The results showed that $ZnCl_2$ changed the pyrolysis process of sisal fiber. Characteristics of activated carbon are: BET surface area was $1628m^2/g$, total pore volume was $1.316m^3/g$ and ratio of mesopore volume to total pore volume up to 94.3%. These results suggest that sisal fiber is an attractive source to prepare mesoporous high-capacity activated carbon by chemical activation with zinc chloride.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3005-3012
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• 2013

The effect of Mn-promotion on high surface area Al-pillared montmorillonite (AlMMT) supported Co nanoparticles prepared by hydrothermal method have been investigated. A series of different weight% Mn-promoted Co nanoparticles were prepared and characterized by XRD, TPR, TGA, BET and SEM techniques. An increase in the surface area of MMT is observed with Al-pillaring. Fischer-Tropsch catalytic activity of the as prepared catalysts was studied in a fixed bed micro reactor at $225^{\circ}C$, $H_2/CO$ = 2 and at 1 atm pressure. The data showed that by the addition of Mn the selectivity of $C_1$ dropped drastically while that of $C_2-C_{12}$ hydrocarbons increased significantly over all the Mn-promoted Co/AlMMT catalysts. The $C_{13}-C_{20}$ hydrocarbons remained almost same for all the catalysts while the selectivity of $C_{21+}$ long chain hydrocarbons decreased considerably with the addition of Mn. The catalyst with 3.5%Mn showed lowest $C_{21+}$ and highest $C_2-C_{12}$ hydrocarbons selectivity due to cracking of long chain hydrocarbons over acidic sites of MMT.

• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.644-649
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• 2006

In this paper, the Cr(VI) adsorption behaviors of activated carbons (ACs) treated by various ozone treatment conditions were studied. The surface properties of the ACs studied were determined by pH, acid-base, and FT-IR measurements. $N_2$ adsorption isotherm characteristics at 77K were confirmed by BET equation, Boer's t-plot method, and Horvath-Kawazoe's slit pore model. Also, the total Cr adsorption amount onto the ACs was measured by ICP-AES. As a result, the ozone treatment led to an increase of oxygen-containing polar functional groups and total acidity as well. Meanwhile, the specific surface areas or micropore volumes were slightly decreased after the ozone treatment due to the micropore filling or blocking. Nevertheless, the total Cr adsorption of ACs was increased with increasing of the ozone treatment time, attributed to the good interaction between Cr ions and polar functional groups on the ACs.

• Journal of Nutrition and Health
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• v.22 no.4
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• pp.257-265
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• 1989

Normal healthy non vegetarian and lact$\infty$,vo­v vegetarian women were studied after they con­S sumed carrot juices as supplements. Daily sup­p plementation resulted in significant increase in serum levels of $\alpha$-, $\beta$-carotene and total carote­n noid in nonvegetarians and $\alpha$-and $\beta$-carotene in lactoovovegetarians. Reflection in serum and $\beta$-carotene was higher in nonvegetarians m than lactoovovegetarians. However, serum caro­t tene values were not significantly different between group after continous supplementation of reducing amounts of carotenes. Serm retionol levels were not changed throughout the study period and were not significantly different bet­w ween nonvegetarians and lactooovegetarians. The results suggest that serm total carotenoid cannot bean indicator of individual carotene such as $\alpha$-or $\beta$-carotene in serum and serum carotene levels are closely related to dietary carotene intake both in nonvegetartins and lac­t toovovegetanans