• Title/Summary/Keyword: Phase Stability

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A Study on the Evaluation of Distribution Stability of Refrigerated Rice Cake Using Natural Antibiotics (천연항균제를 사용한 냉장떡류의 유통 안정성 평가연구)

  • Yoo, Seung Jin;Chin, Jong-eon;Oh, Sung Hoon;Ryu, Min Jung;Hwang, Kwontack
    • Journal of Chitin and Chitosan
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    • v.23 no.4
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    • pp.244-255
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    • 2018
  • Natural extract in liquid phase was adjusted to 0, 0.25, 0.5, 1, 2, and 4% concentration to check microbial changes and to measure 4, 8, $12^{\circ}C$ for refrigeration temperature. In the case of grapefruit extract, the microbial safety was maintained at all the concentrations at $4^{\circ}C$ storage, but the antimicrobial activity was maintained at $12^{\circ}C$ storage and at $8^{\circ}C$ and 21 days storage. In the case of grape seed extract, only the 4% of the culture at $8^{\circ}C$ satisfied the requirement of safety of food distribution for the last 21 days, and the safety criterion was satisfied only at 4% concentration at $12^{\circ}C$ for 18 days. Complex Scutellaria baicalensis extract showed the total number of microbial cells treated by concentration. It was confirmed that microbial flow safety was maintained at low temperature ($4^{\circ}C$). However, at $8^{\circ}C$ and $12^{\circ}C$, Exceeded the distribution limit. When polylysine was applied to brown rice cake, it showed activity in all groups except $4^{\circ}C$, but these properties were not observed at $8^{\circ}C$ and $12^{\circ}C$. At a concentration of 0.5% or more of chitosan, the growth of the microorganism is suppressed by the 21st day very stably, and a similar tendency is observed at 8 and $12^{\circ}C$, so that it may be an antimicrobial material that inhibits microorganisms. At the first day, the distribution standards for general bacterial counts were exceeded.Ethyl-pyruvate showed that microorganism safety was maintained at $4^{\circ}C$ and 1% concentration, and food safety was stable even at 2 or 4%. Glycine showed very good and stable distribution stability at $4^{\circ}C$. However, at $8^{\circ}C$ and $12^{\circ}C$, the shelf life of 14 days could not be maintained as with the addition of other antimicrobial active substances.

Evaluation of the Potential of Nitrogen Plasma to Cosmetics (질소 플라즈마의 화장품 가능성 평가)

  • Lee, So Min;Jung, So Young;Brito, Sofia;Heo, Hyojin;Cha, Byungsun;Lei, Lei;Lee, Sang Hun;Lee, Mi-Gi;Bin, Bum-Ho;Kwak, Byeong-Mun
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.48 no.3
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    • pp.189-196
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    • 2022
  • Plasma refers to an ionized gas that is often referred to as "the fourth phase of matter", following solid, liquid, and gas. Plasma has traditionally been utilized for industrial applications such as welding and neon signs, but its promise in biomedical fields such as cancer treatment and dermatology has lately been recognized. Indeed, due to its beneficial effects in promoting collagen production, improving skin tone, and eliminating harmful bacteria in the skin, plasma treatment constitutes an important target for dermatological research. In this study, a plasma device for cosmetic manufacturing based on nitrogen, the main component of the atmosphere, was designed and assembled. Moreover, nitric oxide (NO) was selected since is easier to follow and evaluate than other nitrogen plasma active species, and its contents were measured to perform a quantitative and qualitative evaluation of plasma. First, an injection method, using different proximities labeled "sinking" and "non sinking" treatments, was performed to test the most efficient plasma treatment method. As a result, it was observed that the formulation obtained by a non sinking treatment was more effective. Furthermore, toner and ampoule were selected as cosmetics formulations, and the characteristics of the formulation and changes in the injected plasma state were observed. In both formulations, the successful injection of NO plasma was 2 times higher in toner formulation than ampoule formulation, and it gradually decreased with time, having dissipated after a week. It was confirmed that the nitrogen plasma used did not affect the stability of the toner and ampoule formulations at low temperature (4 ℃), room temperature (25 ℃), and high temperature (37 ℃ and 50 ℃) conditions. The results of this study demonstrate the potential of plasma cosmetics and highlight the importance of securing the stability of the injected plasma.

Determination of methamphetamine, 4-hydroxymethamphetamine, amphetamine and 4-hydroxyamphetamine in urine using dilute-and-shoot liquid chromatography-tandem mass spectrometry (시료 희석 주입 LC-MS/MS를 이용한 소변 중 메스암페타민, 4-하이드록시메스암페타민, 암페타민 및 4-하이드록시암페타민 동시 분석)

  • Heo, Bo-Reum;Kwon, NamHee;Kim, Jin Young
    • Analytical Science and Technology
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    • v.31 no.4
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    • pp.161-170
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    • 2018
  • The epidemic of disorders associated with synthetic stimulants, such as methamphetamine (MA) and amphetamine (AP), is a health, social, legal, and financial problem. Owing to the high potential of their abuse and addiction, reliable analytical methods are required to detect and identify MA, AP, and their metabolites in biological samples. Thus, a dilute-and-shoot liquid chromatography-tandem mass spectrophotometry (LC-MS/MS) was developed for simultaneous determination of MA, 4-hydroxymethamphetamine (4HMA), AP, and 4-hydroxyamphetamine (4HA) in urine. Urine sample ($100{\mu}L$) was mixed with $50{\mu}L$ of mobile phase consisting of 0.4 % formic acid and methanol and $50{\mu}L$ of working internal-standard solution. Aliquots of $8{\mu}L$ diluted urine was injected into the LC-MS/MS system. For all analytes, chromatographic separation was performed using a C18 reversed-phase column with gradient elution and a total run time of 5 min. The identification and quantification were performed by multiple reaction monitoring (MRM). Linear least-squares regression was conducted to generate a calibration curve, with $1/x^2$ as the weighting factor. The linear ranges were 2.0-200, 1.0-800, and 10-2500 ng/mL for 4HA and 4HMA, AP, and MA, respectively. The inter- and intraday precisions were within 6.6 %, whereas the inter- and intraday accuracies ranged from -14.9 to 11.3 %. The low limits of quantification were 2.0 ng/mL (4HA and 4HMA), 1.0 ng/mL (AP), and 10 ng/mL (MA). The proposed method exhibited satisfactory selectivity, dilution integrity, matrix effect, and stability, which are required for validation. Moreover, the purification efficiency of high-speed centrifugation was clearly higher than 6-15 % for QC samples (n=5), which was higher than that of the membrane-filtration method. The applicability of the proposed method was tested by forensic analysis of urine samples from drug abusers.

A study on the literatherapy effects of Sijo - Focused on the 16th-17th century Gangho Sijo - (시조의 문학 치료적 기능에 관한 고찰 -16.17세기 강호시조를 대상으로-)

  • Kim, Sang-Jean
    • Sijohaknonchong
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    • v.26
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    • pp.25-54
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    • 2007
  • This paper examines the literatherapy effects of Korea's oldest form of literature, Sijo, and its role in the future of literatherapy. Since literature is the expression of human emotions, and therapy is related to medicine, the two seem to have little in common, but they share the function of resolving conflicts. The effectiveness of literatherapy has only recently become a matter of discussion. However, literatherapy is greatly involved with the utility value of literature, and should be taken seriously. This research focused on the literatherapy function of the 16th-17th century Gangho-Sijo. Gangho-Sijo was created by literary men from the Sarim-school, who were removed from their posts in the government due to a massacre(Sawha) and rianly(Dangjaing), and spent most of their time away from politics. Their Sijo were mostly about life in retreat, and their mental state at that time. In relation to literatherapy, the mentality and attitudes of these scholars can be divided into three stages. The first is anxiety and depression, the second tranquility and harmony. and the third serenity. At the final stage, the scholars are liberated from worldly desires. Each of these phases hold the effect of literatherapy. The first stage can relate to 'theory of purgation', ISO-Prinsip, which is based on 'like cures like' which means to treat something with its own kind Fight fire with fire. The second step involves 'theory of purification', and by balancing his emotions, the scholar can achieve mental stability. In the final stage, literatherapy is acquired when the scholar expresses his emotions in a clarification(theory of clarification). At this phase, literatherapy finally has an effect, while the phase itself functions as literatherapy as well. The study of literatherapy is still at its early stages, thus has many limitations. However, literatherapy has bright prospects, and it is my hope that this report will be used as a reference for its further research.

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A Study on the Reaction of Al-1% Si with Ti-silicide (Al-1% Si층과 Ti-silicide층의 반응에 관한 연구)

  • Hwang, Yoo-Sang;Paek, Su-Hyon;Song, Young-Sik;Cho, Hyun-Choon;Choi, Jin-Seog;Jung, Jae-Kyoung;Kim, Young-Nam;Sim, Tae-Un;Lee, Jong-Gil;Lee, Sang-In
    • Korean Journal of Materials Research
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    • v.2 no.6
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    • pp.408-416
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    • 1992
  • Stable TiS$i_2$was formed by RTA on single-Si and on poly-Si. Subsequently, an Al-1% Si layer with 600-nm thick was deposited on top of the TiS$i_2$, Finally, the specimens were annealed for 30min at 400-60$0^{\circ}C$in $N_2$ambient. The thermal stability of Al-1% Si/TiS$i_2$bilayer and interfacial reaction were investigated by measuring sheet resistance, Auger electron spectroscopy (AES), and scanning electron microscopy (SEM). The composition and phase of precipitates formed by the reaction of Al-1% Si with Ti-silicide were studied by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD). In the case of single-Si substrate the reaction of Al-1% Si layer with TiS$i_2$layer resulted in precipitates, consuming all TiS$i_2$layer at 55$0^{\circ}C$. On the other hand, the disappearance of TiS$i_2$on poly-Si occurred at 50$0^{\circ}C$ and more precipitates were formed by the reaction of Al-1% Si/TiS$i_2$on potty-Si substrate than those of the reaction on single-Si substrate. This phenomenon resulted from the fact that Ti-silicide formed on poly-Si was more unstable than on single-Si by the effect of grain boundary. By EDS analysis the precipitates were found tobe composed of Ti, Al, and Si. X-ray diffraction showed the phase of precipitates to be theT$i_7$A$l_5$S$i_12$ternary compound.

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Performance Evaluation of Bio-Membrane Hybrid Process for Treatment of Food Waste Leachate (음식물 침출수 청정화를 위한 파일롯 규모의 생물-분리막 복합공정의 성능 평가 연구)

  • Lee, Myung-Gu;Park, Chul-Hwan;Lee, Do-Hoon;Kim, Tak-Hyun;Lee, Byung-Hwan;Lee, Jin-Won;Kim, Sang-Yong
    • KSBB Journal
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    • v.23 no.1
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    • pp.90-95
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    • 2008
  • In this study, a combined process of sequential anaerobic-aerobic digestion (SAAD), fluidized-bed bioreactor (FBBR), and ultrafiltration (UF) for the treatment of small scale food waste leachate was developed and evaluated. The SAAD process was tested for performance and stability by subjecting leachate from food waste to a two-phase anaerobic digestion. The main process used FBBR composed of aerators for oxygen supply and fluidization, three 5 ton reaction chambers containing an aerobic mesophilic microorganism immobilized in PE (polyethylene), and a sedimentation chamber. The HRTs (hydraulic retention time) of the combined SAAD-FBBR-UF process were 30, 7, and 1 day, and the operation temperature was set to the optimal one for microbial growth. The pilot process maintained its performance even when the CODcr of input leachate fluctuated largely. During the operation, average CODcr, TKN, TP, and salt of the effluent were 1,207mg/L, 100mg/L, 50 mg/L, and 0.01 %, which corresponded to the removal efficiencies of 99.4%, 98.6%, 89.6%, and 98.5%, respectively. These results show that the developed process is able to manage high concentration leachate from food waste and remove CODcr, TKN, TP, and salt effectively.

Non-astronomical Tides and Monthly Mean Sea Level Variations due to Differing Hydrographic Conditions and Atmospheric Pressure along the Korean Coast from 1999 to 2017 (한국 연안에서 1999년부터 2017년까지 해수물성과 대기압 변화에 따른 계절 비천문조와 월평균 해수면 변화)

  • BYUN, DO-SEONG;CHOI, BYOUNG-JU;KIM, HYOWON
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.26 no.1
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    • pp.11-36
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    • 2021
  • The solar annual (Sa) and semiannual (Ssa) tides account for much of the non-uniform annual and seasonal variability observed in sea levels. These non-equilibrium tides depend on atmospheric variations, forced by changes in the Sun's distance and declination, as well as on hydrographic conditions. Here we employ tidal harmonic analyses to calculate Sa and Ssa harmonic constants for 21 Korean coastal tidal stations (TS), operated by the Korea Hydrographic and Oceanographic Agency. We used 19 year-long (1999 to 2017) 1 hr-interval sea level records from each site, and used two conventional harmonic analysis (HA) programs (Task2K and UTide). The stability of Sa harmonic constants was estimated with respect to starting date and record length of the data, and we examined the spatial distribution of the calculated Sa and Ssa harmonic constants. HA was performed on Incheon TS (ITS) records using 369-day subsets; the first start date was January 1, 1999, the subsequent data subset starting 24 hours later, and so on up until the final start date was December 27, 2017. Variations in the Sa constants produced by the two HA packages had similar magnitudes and start date sensitivity. Results from the two HA packages had a large difference in phase lag (about 78°) but relatively small amplitude (<1 cm) difference. The phase lag difference occurred in large part since Task2K excludes the perihelion astronomical variable. Sensitivity of the ITS Sa constants to data record length (i.e., 1, 2, 3, 5, 9, and 19 years) was also tested to determine the data length needed to yield stable Sa results. HA results revealed that 5 to 9 year sea level records could estimate Sa harmonic constants with relatively small error, while the best results are produced using 19 year-long records. As noted earlier, Sa amplitudes vary with regional hydrographic and atmospheric conditions. Sa amplitudes at the twenty one TS ranged from 15.0 to 18.6 cm, 10.7 to 17.5 cm, and 10.5 to 13.0 cm, along the west coast, south coast including Jejudo, and east coast including Ulleungdo, respectively. Except at Ulleungdo, it was found that the Ssa constituent contributes to produce asymmetric seasonal sea level variation and it delays (hastens) the highest (lowest) sea levels. Comparisons between monthly mean, air-pressure adjusted, and steric sea level variations revealed that year-to-year and asymmetric seasonal variations in sea levels were largely produced by steric sea level variation and inverted barometer effect.

Changes of Mineralogical Characteristics of Precipitates in Acid Mine Drainage of the Dalsung Mine and Related Changes of Trace Elements (달성광산 산성광산배수 침전물의 시간에 따른 광물상 특성 변화 및 이에 따른 미량원소의 거동 변화)

  • Yoon, Young Jin;Kim, Yeongkyoo;Lee, Seong-joo
    • Economic and Environmental Geology
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    • v.55 no.5
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    • pp.531-540
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    • 2022
  • Various iron minerals that precipitate in acid mine drainage have a great influence on the concentration change and mobility of trace elements in the drainage during phase transition to other minerals as well as the precipitation process. This study investigated the change of mineral properties and the behaviors of trace elements influenced by pH and time for the precipitates collected from the acid mine drainage treatment system of the Dalsung mine, where schwertmannite is mainly precipitated. However, the main mineral precipitated in the drainage was goethite, suggesting schwetmannite has already undergone a phase transition to goethite to some extent, and it was observed that at higher pH, the peak width at half maximum of XRD peak was narrower. This can be interpreted as the transformation of small amount of amorphous schwetmannite to goethite or an increase in the crystallinity of goethite, and it showed that the higher the pH, the greater this change was. The concentration of Fe was also greatly affected by the pH values, and as the pH increased, the concentration of Fe in the drainage decreased. With increasing time, the Fe concentration increased and then decreased, which can be interpreted to indicate the dissolution of schwertmannite and precipitation of goethite. This mineral change probably resulted in the rapid increase of the concentration of S at initial stage, but its concentration was stabilized later. The concentration of S is also related to the stability of schwetmannite, showing a high concentration at a low pH at which schwertmannite is stable and a low concentration at a high pH at which goethite is stable. The trace elements present as cations in the drainage also showed a close relationship with the pH, generally the lower the pH, the higher the concentration, due to the solubility changes by the pH, and the precipitation and the changes in mineral surface charge at high pH. On the other hand, in the case of As, existing as an anion, although it showed a high concentration at low pH, its concentration increased with time at all pH values, which is probably related to the concentration of Fe which can be coprecipitated in the drainage, and the increase of As concentration with time is also considered to be related to the decrease in schwertmannite rather than the mineral surface charge.

Partial Oxidation of Methane to $H_2$ Over Pd/Ti-SPK and Pd/Zr-SPK Catalysts and Characterization (Pd/Ti-SPK과 Pd/Zr-SPK 촉매상에서 수소 생산을 위한 메탄의 부분산화반응과 촉매의 특성화)

  • Seo, Ho-Joon;Kang, Ung-Il
    • Applied Chemistry for Engineering
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    • v.21 no.6
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    • pp.648-652
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    • 2010
  • Catalytic activities of the partial oxidation of methane (POM) to hydrogen were investigated over Pd(5)/Ti-SPK and Pd(5)/Zr-SPK in a fixed bed flow reactor (FBFR) under atmosphere, and the catalysts were characterized by BET, XPS, XRD. The BET surface areas, pore volume and pore width of Horvath-Kawaze, micro pore area and volume of t-plot of Pd(5)/Ti-SPK and Pd(5)/Zr-SPK were $284m^2/g$, $0.233cm^3/g$, 3.9 nm, $30m^2/g$, $0.015cm^3/g$ and $396m^2/g$, $0.324cm^3/g$, 3.7nm, $119m^2/g$, $0.055cm^3/g$, repectively. The nitrogen adsorption isotherms were type IV with hysteresis. XPS showed that Si 2p and O 1s core electronlevels of Ti-SPK and Zr-SPK substituted Ti and Zr shifted to slightly lower binding energies than SPK. The oxidation states of Pd on the surface of catalysts were $Pd^0$ and $Pd^{+2}$. XRD patterns showed that crystal structures of fresh catalyst changed amorphous into crystal phase after reaction. The conversion and selectivity of POM to hydrogen over Pd(5)/Ti-SPK and Pd(5)/Zr-SPK were 77, 84% and 78, 72%, respectively, at 973 K, $CH_4/O_2$ = 2, GHSV = $8.4{\times}10^4mL/g_{cat}{\cdot}h$ and were kept constant even after 3 days in stream. These results confirm superior activity, thermal stability, and physicochemical properties of catalyst in POM to hydrogen.

Analysis of Physicochemical Characterization and Volatiles in Pure or Refined Olive Oils (국내 유통되는 퓨어 및 정제 올리브유의 이화학적 특성 및 향기 분석)

  • Nam, Ha-Young;Lee, Ju-Woon;Hong, Jang-Hwan;Lee, Ki-Teak
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.36 no.11
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    • pp.1409-1416
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    • 2007
  • Seven selected commercial pure or refined olive oils were obtained from the market, and their physicochemical properties and volatile characterizations were investigated. Fatty acid profiles of the analyzed olive oils showed oleic $(61.2{\sim}74.7mole%)$, palmitic $(10.2{\sim}16.8mole%)$, linoleic $(9.4{\sim}18.0mole%)$, stearic $(1.9{\sim}3.0mole%)$, palmitoleic $(0.7{\sim}2.4mole%)$ and linolenic acid $(0.5{\sim}0.9mole%)$. According to Hunter#s color measurement, pure or refined olive oils showed $L^*$ value of $92.2{\sim}99.0$, $a^*$ value of $-22.2{\sim}-3.2$, and $b^*$ value of $18.5{\sim}55.0$. Their total phenol contents ranged from 1.9 to $13.3mg/100g$ while ${\alpha}-tocopherol$ content showed $7.91{\sim}13.88mg/100g$. Oxidation stability of the pure or refined olive oils were observed by Rancimat. The induction period ranged from 17.37 to 34.72 hr while their POV were $6.83{\sim}20.31meq/kg$ oil. Electronic nose and gas chromatograph-mass spectrometry with head-space solid phase microextraction were applied to identify and discriminate the volatile compounds and flavors in pure or refined olive oils, respectively.