• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.628-628
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• 2013

Graphene, a single layer of graphite, has raised extensive interest in a wide scientific community for its extraordinary thermal, mechanical, electrical and other properties [1,2]. However, because of zero-band gap of graphene, it is difficult to apply for electronic applications. To overcome this problem, chemical doping is one of way to opening grahene bandgap. According to experimental results, by changing doping concentration and doping time, it is possible to control work function of graphene. We can obtain results through raman spectroscopy, UPS, Sheet resistance. Moreover, electronic properties of doped graphene were studied by making field effect transistors. We were able to control the doping concentration, dirac point of graphene and work function of graphene by formng n-type, p-type doping materials. In this research, the chemicals of diazonium salts, viologen, etc. were used for extrinsic doping.

• Journal of the Korean Chemical Society
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• v.7 no.4
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• pp.277-279
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• 1963

The surface tension of solutions of synthesized ammonium caprylate and ammonium caprate was measured by the ring method. The changes with of surface tension of solution of ammonium caprylate showed evidently that the salt had the critical micelle concentration(c.m.c.) at $30^{\circ}C$. The c.m.c. values of above two salts were determined from the change of surface tension of solution with concentration at various temperatures. The temperature dependence of the c.m.c. and the influence of addition of excess ammonia on the c.m.c. were also investigated.

• KSBB Journal
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• v.7 no.3
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• pp.222-228
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• 1992

The effects of sucrose solution on cell growth and berberine production were studied in Thalictrum rugosum cell cultures. Application of sucrose solution without any other components enhanced berberine accumulation significantly in spite of slower cell growth. At high sucrose concentration, cells became very compact and fourfold increase in specific berberine content was achieved. Optimum concentration of sucrose in plain water to maximize the productivity was found to be 8%. Time course experiment in 8% sucrose solution showed that more than 5 days were required to utilize the advantage of this system efficiently. Addition of vitamins, growth regulators, and inorganic salts into the solution was not effective in increasing berberine productivity.

• Journal of the Korean Applied Science and Technology
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• v.12 no.1
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• pp.81-86
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• 1995

Some weight loss accelerating agents, dodecyltrimethylammonium chloride(DTAC), dodecyltrimethylammonium bromide(DTAB), dodecyldimethylammonium chloride(DDBAC), polyoxyethylene(2) dodecylbenzylammonium chloride(PDBAC), and 1-(2-hydroxyethyl)-1-benzyl-2-undecylimidazolinium chloride(AEUIC), were synthesized. As a result of weight loss treatment of the weight loss accelerating agents with NaOH to PET fiber, the increase of weight loss was the order of PDBAC > DDBAC > DTAC > DTAB > AEUIC. Among the weight loss accelerating agents, AEUIC hardly showed weight loss effect, and it was separated into two layer in the NaOH solution at the treatment concentration above 6g/L, but POBAC showed good weight loss effect of 21% that approach almost to a theoretical weight loss, 21.6%, at the concentration above 8g/L.

• Journal of the Korean Electrochemical Society
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• v.5 no.4
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• pp.216-220
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• 2002

The effects of electrolytes on electrochemical behavior from an oil thin layer interposed between a graphite electrode and an aqueous solution phase were examined. A hydrophobic electroactive species, tetrachloro-1,4-benzoquinone (TCQ), in a benzonitrile (EN) layer was employed to study ion transfer properties across the BN-water interface. Experimental results showed that hydrophobic cations as well as anions could be successfully used as ionic charge carriers. The addition of various salts into either the oil layers or the aqueous solutions offers deeper insight for the electrochemistry of the liquid thin layer system. When aqueous perchloric acid is interfaced with the BN films, the perchlorate ion of tetrahexylammonium perchlorate (THAP) substantially suppresses the dissociated proton concentration in the layer by the common ion effect while there is only a little change in the total acid concentration. Further approach by theoretical calculation makes it possible to quantitatively understand the effect of the electrolytes to the electrochemical responses of TCQ, which were previously reported (Anal. Chem. 73, 337 (2001)).

• Bulletin of the Korean Chemical Society
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• v.12 no.4
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• pp.411-413
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• 1991

The effects of electrolyte on the critical micelle concentration (cmc) and bromide counterion binding in the micelles of cetylpyridinium bromide (CPB) have been investigated by UV spectroscopy and conductance measurements. Salts used in this study decreased cmc in the order $Cl^-\;<\;Br^-\;<\;NO3^-$ (which parallels the lyotropic series for the inorganic anions) and the effects on cmc followed the equation proposed by Shinoda: log cmc = A - B log (cmc + [NaX]). In the equation, constant B represents the counterion binding to the micelles at cmc and for the micelle of CPB at $25^{\circ}C$, B=80.76%. The association constant for the binding of counterions to long chain cations within micelles was also derived from the cmc values and counterion binding constant to the micelles.

• Korean Journal of Food Science and Technology
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• v.14 no.2
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• pp.151-155
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• 1982

Effects of vitamins, metabolic intermediates and several inorganic mineral salts on the biomass and lipid accumulation of Mucor plumbeus were investigated after 15 days of incubation at $37^{\circ}C$ under static culture condition. The optimum concentrations of various vitamins were ${\gamma}/l$ for biotin, and 0.01 g/l for nicotinic acid, pyridoxine, thiamine and riboflavin. Among them pyridoxine was the most stimulatory. The maximum felt weight and lipid content per 50ml medium were $2.82{\pm}0.14\;g$ and 62.8%. Triglyceride content of neutral lipid produced under this condition was 64.9%. The major fatty acids were oleic acid (50.0%), linoleic (23.8%) and palmitic acid (13.9%). Malonic acid was considered not to be desirable even though it stimulated the biomass and lipid accumulation because triglyceride content was lowered considerably comparing with control. $MgSO_4{\cdot}7H_2O$ was the most stimulatory among the various magnesium salts and its optimum concentration was 5 g/l. Mucor plumbeus did not require $NaH_2PO_4$ for the stimulation of felt and lipid production. However, the addition of $MnCl_2$ at the concentration of 2 g/l was stimulatory to show $2.76{\pm}0.28\;g$ of felt/50 ml and 56.4% lipid content, and 73.9% triglyceride in the neutral lipid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.1
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• pp.26-32
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• 2012

Purified salt and several different types of sea salts showed comutagenicity in the presence of MNNG (N-methyl-N'-nitro-N-nitrosoguanidine). However, the salts exhibited anti-cancer effects in HCT-116 human colon carcinoma cells and AGS human gastric adenocarcinoma cells. Sea salt showed less comutagenicity effects than purified salt. French sea salt (Salines de Guerande) and Korean sea salt I, which contained higher levels of minerals, showed less comutagenicity. In MTT assay, when HCT-116 and AGS cancer cells were treated with the salts, French sea salt (36% and 34%) and Korean sea salt I (35% and 33%) showed higher anticancer activities than Spanish sea salt (33% and 31%), Italian sea salt (29% and 27%), Korean sea salt II (22% and 22%), or purified salt (18% and 15%) at a salt concentration of 1%. French sea salt and Korean sea salt I also showed better anticancer activities than the other salt samples at a low concentration of 0.5% (p<0.05). Apoptosis related genes of Bax and Bcl-2 were regulated by the treatment of the salt in the colon cancer cells. French sea salt and Korean sea salt I especially increased Bax mRNA expression, but decreased Bcl-2 expression, indicating that they can induce apoptosis of the cancer cells. From the experimental results, sea salt showed better health functional effects than the purified salt, and French sea salt and Korean sea salt I which contained high levels of Ca, K, and Mg showed better effects.

• Applied Biological Chemistry
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• v.24 no.1
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• pp.7-14
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• 1981

Among the Basidiomycetes, Pleurotus ostreatus 301 and Lentinus edodes 3-1 were chosen because of their good enzyme productivity and rapid mycelial growth in rice straw medium. Their cultural conditions adequate for the enzymes production and effects of various materials and inorganic salts added to thd rice straw media were investigated. L. edodes 3-1 was excellent in productivity of cellulase and xylanase, and P. ostreatus 301 in protease. The optimum conditions for enzyme production were at $30^{\circ}C$ in cellulase production and at $25^{\circ}C$ in xylanase and protease production, with 75% moisture content and 5.0-6.0 initial pH. The appropriate cultural periods, for enzyme production were 30 days and 35 days for P. ostreatus 301 and L. edodes 3-1, respectively. Among the various materials added, defatted soybean, defatted rape seed, or defatted sesame were all effective to enzyme production but reduced mycelial growth. Rice bran was also effective, particularly at 30% concentration. The addition of inorganic salts showed effective to enzyme production. Among inorganic salts, optimum concentration of $CaCO_3$ was 5%, and that of $CaSO_4$ was 2%.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.57-61
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• 1992

For testing salts effect on seed germination, nitrogen solutions($(NH_4)_2SO_4$, $NH_4NO_3$, $KNO_3$, $Mg(NO_3)_2$, $Ca(NO_3)_2$, $(NH_2)_2CO$) were treated to chinese cabbage(Brassica rape L.) and lettuce(Lactuca sativa L.) seeding on the quartz sand bed given a tilt to wet by dripping. Electrical conductivities (mS/cm) increased with direct proportion by equivalent gram-molecular weight at $(NH_4)_2SO_4$ and $KNO_3$, $NH_4NO_3$, but those of Mg and Ca salt remained 1 1/2 times higher. And urea solution never showed EC at all. $(NH_4)_2SO_4$ solution appeared to have value of EC with 1.37 times as high as that of $KNO_3$ and it was in order of $(NH_4)_2SO_4>NH_4NO_3>KNO_3>Ca(NO_3)_2>Mg(NO_3)_2$ comparing with same percentage solution. Application of $Mg(NO_3)_2$ and $(NH_4)_2SO_4$ among 6 salts resulted in a severe decreas in germination of both crops, and $NH_4NO_3$ showed light inhibition in comparison to $KNO_3$. Urea showed little effect on germination as the same as $Ca(NO_3)_2$ and $KNO_3$ solution at low concentrations, but the latter two salts reduced germination remarkably at high concentrations. It is likely to show that germination inhibition is not affected by salt salanity but by the sort of salts.