• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1023-1028
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• 2014

Protonated caffeine ($CH^+$) and glucosamine ($GH^+$) overlapped in an analysis with ion mobility spectrometryquadrupole mass spectrometry. Ethyl lactate vapor (L) at different concentrations from 0 to 22 mmol $m^{-3}$ was added as a buffer gas modifier to separate these signals. The drift times of $CH^+$ and $GH^+$ increased with L concentration. The drift time increase was associated to clustering equilibria of $CH^+$ and $GH^+$ with one molecule of L and the equilibrium of $GH^+$ was more displaced to the formation of $GLH^+$ than that of $GLH^+$. $GH^+$ clustered more to L than $CH^+$ because $GLH^+$ formed more stable hydrogen bonds (26.30 kcal/mol) than $GLH^+$ (24.66 kcal/mol) and the positive charge in $GH^+$ was more sterically accessible than in $CH^+$. The aim of this work was to use theoretical calculations to guide the selection of a buffer gas modifier for IMS separations of two compounds that overlap in the mobility spectra and predict this separation, simplifying that empirical process.

• Membrane Journal
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• v.24 no.5
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• pp.358-366
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• 2014

Chitosan-HNT (halloysite nanotube) composite membranes were prepared by the addition of HNT 0, 3, 5, and 10 wt%. The structure of composite membranes were studied by FT-IR, XRD, TGA, and SEM. Gas permeation experiment were performed under condition of $30^{\circ}C$ and $4kgf/cm^2$. Gas permeability and selectivity were investigated by increasing the amount of HNT contents in the chitosan. Chitosan-HNT composite membrane for $CO_2$ and $CH_4$ showed the maximum value at 3 wt% of HNT content and decreased thereafter. The selectivity of ($CO_2/CH_4$) was increased due to its affinity with the OH groups on the HNT, was shown in the range of 1.3 to 3.8 at 0~10 wt%.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.1
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• pp.111-122
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• 1995

12 populatiDns of Ch indicum L. and it's variation antogenous in Tforea were selected throughout the country and their morphological characteristics were studied in this paper. The results are as follows. 1) The mean of the plant height is 97.3cm. Ch. indicunl is 76.5cm and Ch. boreale is 116. 6cm in height. The number of nodes is 58 on the average. The color of the stem is generally black-red in the case of Ch. indicum and is green for Ch. boreale. 2) The leaves of Ch. inficum are smaller In size and thicker than chose of Ch. boreale, and it has a stipule. This fact enables us to distinguish one species from the other, however, the Gyukpo-population of Ch. indicum has a large leaf, and Byunsan-population of Ch. boreale has a stipule so that the above fact is not an exact criterion on which to base one classification. 3) The size of the capitulum is 24.9mm for Ch. indicum and 15.6mm in the case of Ch. boreaje so that the difference between species is admitted. It was confirmed hat the size of the capitulum has positive correlation to that of the pedicel and has egative correlation to the number of flowers, so that of inflorescence, Ch. indicumhas corymb, and Ch. boreale has crowed corymb or umbel-type.The number of ligulates is 19 on the average, which no the difference being founnd between species and populations.4) The cluster analysis of morphological characteristics showed that Ch. indicum wasdivided into two groups, which was shown thought to be due to the difference of speciesbetween Ch. indicum and Ch. boreale. However, it could not be shown that their morphological characteristics explain a geographical relationship between populations

• Journal of Sensor Science and Technology
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• v.24 no.4
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• pp.258-263
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• 2015

In order to prevent drink-driving by detecting concentration of alcohol from driver's exhale breath, twenty chemical sensors fabricated. The one of purposes for sensor array which consists of those sensors is to discriminate between target gas(alcohol) and interference gases($CH_3CH_2OH$, CO, NOx, Toluene, and Xylene). Wilks's lambda was presented to achieve above purpose and optimal sensors were selected using the method. In this paper, step-wise sensor elimination based on Euclidean distance was investigated for selecting optimal sensors and compared with a result of Wilks's lambda method. The selectivity and sensitivity of sensor array were used for comparing performance of sensor array as a result of two methods. The data acquired from selected sensor were analyzed by pattern analysis methods, principal component analysis and Sammon's mapping to analyze cluster tendency in the low space (2D). The sensor array by stepwise sensor elimination method had a better sensitivity and selectivity compared to a result of Wilks's lambda method.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.4
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• pp.471-478
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• 2011

The objectives were to compare the ability of various rumen microbial fractions to reduce nitrate and to assess the effect of nitrate on in vitro fermentation characteristics. Physical and chemical methods were used to differentiate the rumen microbial population into the following fractions: whole rumen fluid (WRF), protozoa (Pr), bacteria (Ba), and fungi (Fu). The three nitrogen substrate treatments were as follows: no supplemental nitrogen source, nitrate or urea, with the latter two being isonitrogenous additions. The results showed that during 24 h incubation, WRF, Pr and Ba fractions had an ability to reduce nitrate, and the rate of nitrate disappearance for the Pr fraction was similar to the WRF fraction, while the Ba fraction needed an adaptation period of 12 h before rapid nitrate disappearance. The WRF fraction had the greatest methane ($CH_4$) production and the Pr fraction had the greatest prevailing $H_2$ concentration (p<0.05). Compared to the urea treatment, nitrate diminished net gas and $CH_4$ production during incubation (p<0.05), and ammonia-N ($NH_3$-N) concentration (p<0.01). Nitrate also increased acetate, decreased propionate and decreased butyrate molar proportions (p<0.05). The Pr fraction had the highest acetate to propionate ratio (p<0.05). The Pr fraction as well as the Ba fraction appears to have an important role in nitrate reduction. Nitrate did not consistently alter total VFA concentration, but it did shift the VFA profile to higher acetate, lower propionate and lower butyrate molar proportions, consistent with less $CH_4$ production by all microbial fractions.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.4
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• pp.275-281
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• 2020

Purpose: Development of a latent antimicrobial soft liner is strongly needed to overcome a possible inflammation related with its dimensional degrade or surface roughness. Modified tissue conditioner (TC) containing chitosan-doped silver nanoparticles (ChSN) complexes were synthesized and assessed for their characterizations. Materials and methods: ChSN were preliminarily synthesized from silver nitrate (AgNO₃), sodium borohydride (NaBH₄) as a reducing agent and chitosan biopolymer as a capping agent. Ultraviolet-visible and Fourier transform infrared spectroscopy were conducted to confirm the stable reduction of nanoparticles with chitosan. Modified TC blended with ChSN by 0 (control), 1.0, 3.0 and 5.0 % mass fraction were mechanically tested by ultimate tensile strength (UTS), silver ion elution and color stability (n=7). Results: At 24 hour and 7 day storage periods, UTS values were not significant (P>.05) as compared with pristine TC (control) and silver ion was detected with the dose-dependent values of ChSN incorporated. Color stability of TC were influenced by ChSN add, with the higher doses, the significantly greater color changes (P<.05). Conclusion: A stable synthesized ChSN was acquired and modified TC loading ChSN was characterized as silver ion releasing without detrimental physical property. For its clinical application, antimicrobial test, color control and multifactor investigations are still required.

• Journal of the Korean Chemical Society
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• v.24 no.4
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• pp.288-294
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• 1980

Methanolysis rate constants were determined for $CH_3O(CO)Cl,\;CH_3S(CO)Cl\;and\;CH_3S(CS)Cl\;in\;CH_3OH-CH_3CN$ mixtures. Results show that the rates are not predominantly influenced by the bulk solvent properties but are partly influenced by specific electrophilic solvation.Polarity of the solvent is not a dominant factor but it nevertheless plays a role in charge stabilization of the $S_N1$ like transition state. The methanolysis proceeds through $S_N1$ mechanism for $CH_3S(CS)Cl$ for which both specific solvation of leaving group by methanol and charge stabilization by a high dielectric medium are important, while for $CH_3O(CO)Cl\;methanolysis occurs\;via\;S_N2$ mechanism in which both of the solvent effects are unimportant.

• Journal of Animal Science and Technology
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• v.63 no.1
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• pp.16-24
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• 2021

The suppressive effect of monensin as an ionophore-feed additive on enteric methane (CH4) emission and renewable methanogenesis were evaluated. To clarify the suppressive effect of monensin a respiratory trial with head cage was performed using Holstein-Friesian steers. Steers were offered high concentrate diets (80% concentrate and 20% hay) ad libitum with or without monensin, galacto-oligosaccharides (GOS) or L-cysteine. Steers that received monensin containing diet had significantly (p < 0.01) lower enteric CH4 emissions as well as those that received GOS containing diet (p < 0.05) compared to steers fed control diets. Thermophilic digesters at 55℃ that received manure from steers fed on monensin diets had a delay in the initial CH4 production. Monensin is a strong inhibitor of enteric methanogenesis, but has a negative impact on biogas energy production at short retention times. Effects of the activity of coprophagous insects on CH4 and nitrous oxide (N2O) emissions from cattle dung pats were assessed in anaerobic in vitro continuous gas quantification system modified to aerobic quantification device. The CH4 emission from dungs with adults of Caccobius jessoensis Harold (dung beetle) and the larvae of the fly Neomyia cornicina (Fabricius) were compared with that from control dung without insect. The cumulative CH4 emission rate from dung with dung insects decreased at 42.2% in dung beetles and 77.8% in fly larvae compared to that from control dung without insects. However, the cumulative N2O emission rate increased 23.4% in dung beetles even though it reduced 88.6% in fly larvae compared to dung without coprophagous insects. It was suggested that the antibacterial efficacy of ionophores supplemented as a growth promoter still continued even in the digested slurry, consequently, possible environmental contamination with the antibiotics might be active to put the negative impact to land ecosystem involved in greenhouse gas mitigation when the digested slurry was applied to the fields as liquid manure.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.4
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• pp.135-142
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• 2009

In order to predict frostfall, nocturnal cooling rate and air temperature changes were analyzed on days with and without frost when the maximum temperature was lower than $20^{\circ}C$. In general, the nocturnal cooling rates on frosty days were higher than those on non-frosty days. The cooling rates averaged from 19:00 to 24:00 on frosty and non-frosty days were $1.7^{\circ}Ch^{-1}$ and $0.7^{\circ}Ch^{-1}$ respectively. As expected, the nocturnal temperature on frosty days was lower than that on non-frosty days. Especially, the midnight air temperature averaged about $3.9{\pm}1.5^{\circ}C$ on frosty days, which was lower than that on non-frosty days (i.e., $10.1{\pm}2.9^{\circ}C$). The discriminant analysis using three independent variables (i.e., total cloud amount, air temperature at 24:00, and 5-day rainfall amount) successfully classified the presence of frost with 87% accuracy.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.2
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• pp.117-122
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• 1991

Microbial organisms including yeast, Acinetobacter sp. AG-3, Chlorococcum sp., Chlorella sp. and some of their combinations were tested to evaluate growth efficiency of Tigriopus japonicus. Body length and weight of the copepoda were measured during four days experiment. Acinetobacter sp. AG-3, dried yeast(produced Wago), Chlorella sp., Chlorococcum sp. and mixed culture were used as food sources. Yeast(Y.) was the most effective food for the growth during nauplius stage and efficiencies of bacteria(Bact.)+chlorococcum sp.(RA), Chlorococcum sp.(RA), Bact.+chlorella sp.(Ch.), Bact. and Ch. decreased in odor, while for the growth of copepodite and adult, Bact.+RA was the most effective food with decreased efficiency of Y., RA, Bact. + Ch., Bact., Ch. in order. The ratio of weight gain to the food uptaken, after the weight and food units were converted to carbon, was between 21.6 and $68.7\%$, This result suggests that some kinds of bacteria, algae and mixed cultural microorganisms could be good food sources for the growth of copepoda.