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The Measurement of Flash Point for Binary Mixtures of 2,2,4-Trimethylpentane, Methylcyclohexane, Ethylbenzene and p-xylene at 101.3 kPa

  • Hwang, In Chan;In, Se Jin
    • Clean Technology
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    • v.26 no.4
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    • pp.279-285
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    • 2020
  • Laboratories and industrial processes typically involve the use of flammable substances. An important property used to estimate fire and explosion risk for a flammable liquid is the flash point. In this study, flash point data at 101.3 kPa were determined using a SETA closed cup flash point tester on the following solvent mixtures: {2,2,4-trimethylpentane + methylcyclohexane}, {2,2,4-trimethylpentane + ethylbenzene}, and {2,2,4-trimethylpentane + p-xylene}. The purpose of this work is to obtain flash point data for binary mixtures of 2,2,4-trimethylpentane with three hydrocarbons (methylcyclohexane, ethylbenzene, and p-xylene), which are representative compounds of the main aromatic hydrocarbon fractions of petroleum. The measured flash points are compared with the predicted values calculated using the GE models' activity coefficient patterns: the Wilson, the Non-Random Two-Liquid (NRTL), and the UNIversal QUAsiChemical (UNIQUAC) models. The non-ideality of the mixture is also considered. The average absolute deviation between the predicted and measured lower flash point s is less than 1.99 K, except when Raoult's law is calculated. In addition, the minimum flash point behavior is not observed in any of the three binary systems. This work's predicted results can be applied to design safe petrochemical processes, such as identifying safe storage conditions for non-ideal solutions containing volatile components.

Thermoelectric Properties of Rapidly Solidified and extruded N-type $Bi_2Te_{2.85}Se_{0.15}$ alloy with extrusion die angle (급속응고법에 의한 $Bi_2Te_3$계 N형반도체 열전재료의 압출 다이각 변화에 따른 열전특성)

  • 권동진;홍순직;손현택;천병선;이윤석
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2001.11a
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    • pp.29-29
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    • 2001
  • 열전재료는 열전현상을 가지고 있어 열전발전과 열선냉각이 가능하기 때분에 해저용, 우주용, 군사용의 특수 전원으로 이미 실용화되어있고, 반도체, 레이저 다이오드, 적외선 검출소자 등의 냉각기로 쓰여지고 있어 많은 연구자들이 이들 재료에 대한 연구에 관을 갖고 열전특성을 향상시키기 위하여 많은 연구를 진행하고 있다 이들 열전재료는 사용 온도구역에 따라 3종류로 구분하고 있으며, 실온부근의 저온 영역(20$0^{\circ}C$)이하에서는 $Bi_2Te_3$계 재료, 중온영역(20$0^{\circ}C$~50$0^{\circ}C$)에서sms (Pb,Ge) Te계 재료, 고온영역(50$0^{\circ}C$~lOoo$^{\circ}C$)에서는 Si-Ge계 Fe Si계 재료가 이용되고 있다. 본 연구에서는 실온에서 성능지수가 높은 Bi_2(Te,Se)_3$에 대한 연구를 진행하였다. Bi_2(Te,Se)_3$계 열전재료는 기존의 공법인 Zone melting법을 이용하는 경우 성능지수가 높으나, 단위정이 Rhombohedral 구조파 기저면(basal plane)에 벽개성이 있는 관계로 재료의 적지 않은 손실과 가공상의 어려움이 있다. 또한 사료전체에 걸쳐 화학적으로 균질한 고용체를 얻는 것도 어려운 문제점으보 부각되고 있디 따라서 이와같은 문제점을 보완하기 위하여 용질원자의 편석감소, 고용도의 증가, 균일 고용체 형성, 결정립의 미세화등의 장점이 있는 급속응고법을 본 연구에 응용하였다. 본 연구에서는 위에서와 같은 급속응고의 장점과 대량 가공이 능늪한 연간압출공정을 이용하여 제조된 분말을 성형화 하였다. 특히 열간압출 가공에 있어서 압축다이 각 변화는 재료의 소성유동에 매우 중요한 역하을 하게되며, 이와 갇은 소성유동은 본 재료의 열전특성에 중요한 영향을 미치는 C 면 배양에 중요한 역할을 한 것으 로 기대된다. 이에 본 연구에서는 압출다이 각도 변화에 따른 미세조직변화와 이들 조직이 강도와 열전특성에 미치는 영향을 석하고자 한다. 압출재의 미세조직은 XRD(X Ray Diffraction), SEM(Scanning Electron Microscopy)으로 분석하였으며, 열전특성인 Seebeck계수($\alpha$)와 전기비저항( $\rho$ )은 열전측정장치로, 기계적 강도는 MTS장비를 이용하여 이루어졌다. 또한 압축다이각도 변화에 따른 결정방위 해석은 모노크로미터가 장착된 X RD장비감 이용하여 분석되었다.

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Study on the Shapes of Jung-kwa, Gi-kwa, Sin-kwa, Hyul-kwa (정기신혈과(精氣神血科)의 형상(形象)에 대한 연구)

  • Choi Byung-Tae;Choi Yung-Hyun;Baek Geun-Gi;Lee Yong-Tae
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.19 no.5
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    • pp.1181-1190
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    • 2005
  • After study about the shapes of Jung, Gi, Sin, Hyul-kwa advocated by Master Jisan, the conclusions are drawn as follows. It pursues the rules of universe being changed from formless to concrete objects that the Body Essence, Vital energy, Mentality, and Blood are materialized to Jung, GE, Sin, Hyul-kwa. It can be drawn an inference from the next three theories that Jisan considered Jung, Gi, Sin, Hyul-kwa as round, square, reverse triangle, and triangle or oval shape. First, it was taken to following the shapes of viscera. Namely Jung-kwa was taken as Kidney, Gi-kwa as Lung, Sin-kwa as Heart, Hyul-kwa as Liver. Second, it was adopted from five kinds of constitutions according to the five elements in [Yeongchu Yin and Yang twenty five shapes] that is Jung-kwa is purchased with Water-earth phases, Gi-kwa with metal phase Sin-kwa with fire phase, Hyul-kwa with Wood phase, Third, it is taken in order to eliminate contradictions. Hyul-kwa disliking to move is assumed to round shape to easily move. Gi-kwa tending to disperse is chosen to square in order to be unmoved. Sin-kwa declining to stagnate of seven emotions is pursued to reverse triangle to compose oneself. Hyul-kwa inclining to gather is preferred to acreage phase to harmonize ascending tendency. Among shapes which Jisan was divided Hado, Nakseo, Bokhee pal kwoe, Moonwang pal kwoe, Jung-kwa as round is Hado, Gi-kwa as square is Nakseo, Sin-kwa as reverse triangle is Bokhee pal kwoe order shape, Hyul-kwa as acreage phase or oval shape is accord with Moonwang pal kwoe order shape. The reason being classified into Jung, GE, Sin, Hyul-kwa from the shapes of the face is that the face is the place to reflect the whole conditions of the body connected with all of the viscera and meridian system such as semen of plants. Above contents are drawn an inference from the transcription of Jisan's lectures and his writings. And it is considered that insufficient parts of the Jisan's theory must be demonstrated continuously.

Effects of different inorganic: organic zinc ratios or combination of low crude protein diet and mixed feed additive in weaned piglet diets

  • Oh, Han Jin;Kim, Myung Hoo;Lee, Ji Hwan;Kim, Yong Ju;An, Jae Woo;Chang, Se Yeon;Go, Young Bin;Song, Dong Cheol;Cho, Hyun Ah;Jo, Min Seok;Kim, Dae Young;Kim, Min Ji;Cho, Sung Bo;Kim, Hyeun Bum;Cho, Jin Ho
    • Journal of Animal Science and Technology
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    • v.64 no.1
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    • pp.23-37
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    • 2022
  • Thirty-six weaned piglets with an initial body weight (BW) of 8.43 ± 0.40 kg (28 days of age, ([Landrace × Yorkshire] × Duroc) were randomly assigned to 6 treatments for a 2-week feeding trial to determine the effects of different inorganic zinc (IZ), organic zinc (OZ) or combination of low crude protein diet (LP) and Mixed feed additive (MFA) on diarrhea score, nutrient digestibility, zinc utilization, blood profiles, organ weight, and fecal microflora in weaned piglet diet. The pigs were individually placed in 45 × 55 × 45 cm stainless steel metabolism cages in an environmentally controlled room (30 ± 1℃). The dietary treatments included a negative control (NC), positive control (PC; zinc oxide, 1,000 mg/kg), T1 (IZ : OZ, 850 : 150), T2 (IZ : OZ 700 : 300), T3 (IZ : OZ, 500 : 500), and T4 (LP + MFA [0.1% Essential oils + 0.08% Protease + 0.02% Xylanase]). The daily feed allowance was adjusted to 2.7 times the maintenance requirement for digestible energy (2.7 × 110 kcal of DE/kg BW0.75). This allowance was divided into two equal parts, and the piglets were fed at 08 : 30 and 17 : 30 each day. Water was provided ad libitum through a drinking nipple. The diarrhea score was significantly increased (p < 0.05) in NC treatment compared with other treatments. The apparent total tract digestibility (ATTD) of dry matter (DM), nitrogen (N), and gross energy (GE) was significantly increased (p < 0.05) in the T2 treatment compared with the PC and NC treatments in week 1. In week 2, the ATTD of DM, N, and GE was significantly decreased (p < 0.05) in the NC treatment compared with other treatments. The T3 treatment had significantly higher (p < 0.05) ATTD and apparent ileal digestibility of zinc than the PC and T1 treatments. The Escherichia coli count in feces was significantly decreased in the T4 treatment compared with the NC and T2 treatments. The Lactobacillus count in feces was significantly increased in the T4 and T1 treatment compared with the T2 and T3 treatments. In conclusion, IZ : OZ 500 : 500 levels could improve nutrient digestibility and zinc utilization in weaned piglets, Moreover, MFA in LP diets could be used as a zinc alternative.

Verification of Recycled Plastic Pellets and Mucuna pruriens Extracts Correlation of Antioxidant Efficacy (재활용 플라스틱 펠렛과 벨벳콩(Mucuna pruriens) 추출물의 항산화 효능 상관관계 검증)

  • Dong-Geun Han;Min-jun Bae;GE-GE;Hyun-Jeong Kim;Se-Gie Kim;Bong-Jeon An
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.49 no.1
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    • pp.29-38
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    • 2023
  • In this study, the correlation between recycled plastic pellets and the antioxidant efficacy of the extract of Mucuna pruriens (M. pruriens) was verified. After immersing recycled plastic pellets in M. pruriens extracts, they were stored for 30 days under various temperature conditions, and then analyzed for DPPH radical and ABTS+ radical erasing ability, SOD-like activity, total phenol and flavonoid content. Compared to the existing efficacy, DPPH radical elimination showed less than 30% activity change in ECOTRIA and PCR-PP pellets, and the largest decrease in activity of 46.06% was confirmed in Grico pellets. As a result of measuring ABTS+ radical erasure ability, less than 5% of efficacy change was confirmed in all pellets. As a result of measuring SOD-like activity, all showed a decrease in activity of more than 30%, and as a result of measuring the total phenol and flavonoid content, all pellets showed a tendency to decrease compared to the existing content. Through this results, it was confirmed that the physiological activity of M. pruriens extract decreased and changed by recycled plastic pellets, and based on the results of this study, recycled plastic pellets are believed to affect the existing efficacy and activity stability of M. pruriens extract.

Analysis and Comparison of MR Signal Strength and SNR Value for Optimal FOV (최적의 FOV를 위한 MR신호강도와 신호 대 잡음비 값의 비교분석)

  • Lee, Sang-Ho
    • Journal of radiological science and technology
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    • v.41 no.2
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    • pp.109-113
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    • 2018
  • Despite the continuous development of software, it is continuously pursued to enlarge the examination area of FOV in order to reduce the factors of inconsistency in images that appear in continuous examination during wide area examination using contrast agent such as whole body angiography. In this study, we investigated the optimal FOV by comparing the SNR values according to the changes of FOV. The change of the FOV was gradually changed to $270{\times}200$, $300{\times}223$, $330{\times}244$, $360{\times}266$ and $380{\times}281$. SE images at TR 450 msec and TE 10 msec, FSE images at TR 2,000 msec, TE 80 msec, and GE images were scanned at TR 117 msec, and TE 16 msec. SNR values were calculated from the mean values of signal intensities of five phantom images and the signal intensity values of four background standard deviations. As a result of the study, the signal intensity and the SNR value according to the change of the FOV value gradually increased as the FOV was increased, but it was found that the SNR value decreased at a constant size. In conclusion, the results are different from previous studies that the SNR increases as the FOV increases. The cause of these results could not be confirmed. However methods that can be imaged and included within the effective FOV should be considered.

Surgical Treatment of Lumbar Spinal Stenosis in Geriatric Population : Is It Risky?

  • Kim, Dong-Won;Kim, Sung-Bum;Kim, Young-Soo;Ko, Yong;Oh, Seong-Hoon;Oh, Suck-Jun
    • Journal of Korean Neurosurgical Society
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    • v.38 no.2
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    • pp.107-110
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    • 2005
  • Objective : Lumbar spinal stenosis is increasingly recognized as a common cause of low back pain in elderly patients. Conservative treatment has been initially applied to elderly patients, however, surgical treatment is sometimes indispensable to relieve severe pain. We retrospectively examine the age-related effects on the surgical risk, and results following general anesthesia and operative procedure in geriatric patients for two different age groups of at least 65years old. Methods : Consecutive 51 patients [${\ge}$ 65years], who underwent open surgical procedure for degenerative lumbar spinal stenosis, were selected in the study. Patients were divided into two groups. Group A included all patients who were between 65 and 69years of age at the time of surgery. Group B included all patients who were at least 70years of age at the time of surgery. We reviewed medical history including preoperative American Society of Anesthesiologists[ASA] classification of physical status, anesthetic risk factor, operative time, estimated blood loss, transfusion requirements, hospital stay, operated level, and clinical outcome to look for comparisons between two age groups [$65{\sim}69$ and over 70years]. Results : In preoperative evaluation, mean anesthetic risk factor of patients was numerically similar between the groups. The American Society of Anesthesiologists classification of physical status was similar between two groups. There was no difference in operated level, operative time, estimated blood loss, hospital stay, and anesthetic risk factor between the two groups. The clinical successful outcome showed 82.7% for Group A and 81.8% for group B. The overall postoperative complication rates were similar for both group A and B. Conclusion : We conclude that advanced age per se, did not increase the associated morbidity and mortality in surgical decompression for spinal stenosis.

Swelling-activated $Cl^-$ Channels in Human Salivary Gland Acinar Cells

  • Chung, Ge-Hoon;Sim, Jae-Hyun;Kim, Soung-Min;Lee, Jong-Ho;Chun, Gae-Sig;Choi, Se-Young;Park, Kyung-Pyo
    • International Journal of Oral Biology
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    • v.34 no.3
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    • pp.151-155
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    • 2009
  • The role of $Cl^-$ channels in regulatory volume decrease (RVD) in human salivary gland acinar cells was examined using a whole-cell patch clamp technique. Human tissues were obtained from healthy volunteers or from patients with oromaxillofacial tumors. During the measurements, $K^+$-free solutions were employed to eliminate contamination of whole-cell conductance by $K^+$ currents. When the cells were exposed to a 70% hypotonic solution, outward-rectifying currents, which were not observed in the resting state, were found to have significantly increased both in human labial and parotid gland acinar cells. The amplitudes of the currents were reduced in a low $Cl^-$ bath solution. Furthermore, the addition of $100{\mu}M$ 5-Nitro-2- (3-phenyl propylamino) benzoic acid (NPPB) or $100{\mu}M$ 4,4'-diisothio cyanatostilbene-2,2'-disulphonic acid (DIDS), known to partially block $Cl^-$ channels, significantly inhibited these currents. Its outward-rectifying current profile, shift in reversal potential in a low $Cl^-$ bath solution and pharmacological properties suggest that this is a $Ca^{2+}$-independent, volume activated $Cl^-$ current. We conclude therefore that volume activated $Cl^-$ channels play a putative role in RVD in human salivary gland acinar cells.

Automatic Exposure Control Performance Evaluation of Digital Radiographic Imaging System by Manufacturer Using Coins (동전을 이용한 제조사 별 디지털 방사선 영상 시스템의 자동노출제어 성능 평가)

  • Lim, Se-Hun;Seoung, Youl-Hun
    • Journal of radiological science and technology
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    • v.45 no.1
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    • pp.1-9
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    • 2022
  • In this study, we proposed an image quality control for an automatic exposure control (AEC) of digital radiographic imaging system and tried to analyze the performance of the AEC by various manufacturer. The subjects of the experiment were analyzed for the AEC image quality evaluation using digital radiation generators from four manufacturer such as PHILIPS, GE Healthcare, SAMSUNG Healthcare, DK Medical Solution. We used as materials for the implementation of the image quality evaluation by coins (500 won, KOMSCO, Korea). This study evaluated the performance evaluation of the AEC as image quality and exposure dose (Milliampere-seconds; mAs). The image quality evaluation was tried visual assessment by two radiologic technologists and contrast to noise (CNR) by ImageJ. The exposure dose investigated mAs on digital radiation generators. The radiographic coin images acquired 360 images based on change in the control factors of the AEC, which were kVp, the consistency of field configuration and dominant zone, sensitivity and density. As a result, there was a significant difference in the AEC performance between manufacturer. The CNR by the AEC for each manufacturer showed a difference of up to about 1.9 times. The exposed tube current by the AEC for each manufacturer showed a difference of up to about 5.8 times. It is expected that our proposed evaluation method using coins could be applied as the AEC performance evaluation method in the future.

Revaluation of Ore Deposits within the Yeongam District, Cheollanamdo-Province: The Eunjeok and Sangeun Mines (전남 영암지역 광상 재평가: 은적.상은 광산를 중심으로)

  • Heo, Chul-Ho;Park, Sung-Won;Lee, Jae-Ho
    • Economic and Environmental Geology
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    • v.43 no.2
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    • pp.73-84
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    • 2010
  • Gold and silver deposits within the Eunjeok and Sangeun mines are located in Yeongam district, Cheollanamdo-province. They are composed of vein ore bodies infilling the fractures of Cretaceous rhyolitic tuff. The Eunjeok mine have three gold and silver bearing hydrothermal veins which is infilling the fracture of rhyolitic tuff. Major ore minerals within the Eunjeok and Sangeun mines are arsenopyrite, pyrite, chalcopyrite, sphalerite and galena and minor ores are electrum, native silver and argentite. Sericitization is dominant in alteration zone and chloritization and dickitization is minor. Quartz veins in the Eunjeok and Sangeun mine have the similar paragenesis and vein textures such like breccia, crustiform, comb and vuggy morphology indicating the formation of typical epithermal environment. In order to carry out the preliminary feasibility study of mine according to the commodity and elucidate the occurrence features of mineral resources from Eunjeok and Sangeun mine, common commodity (Pb, Zn, Cu, Fe, Mo, W, Au and U), and industrial commodity (In, Re, Ga, Ge, Se, Te, Y, Eu and Sm) for 17 ore specimen were analyzed. It is tentatively thought that there is no exploitable mine for iron, lead, zinc, copper, tungsten and uranium based on the preliminary result. If the reserves are secured through the detailed prospecting in case of molybdenum and silver, it is tentatively thought that there will be exploitable deposits depending on international metal price. If we assume the vein width from 0.25 m to 2 m including alteration zone with the gold grade of 80g/t, it is inferred that the resources amount of the Eunjeok-Sangeun mines range from 6.5 to 65ton. However, as the vein structure of the Eunjeok and Sangeun mines is developed together with alteration zone, it should be estimated to include potential alteration zone in order to yield the average grade. It is needed to carry out more exploration in the near future because the reserves can be flexibly estimated according to the change of average grade considering the alteration zone.