• Analytical Science and Technology
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• v.20 no.6
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• pp.516-523
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• 2007

Purification of silica mineral has been investigated by acid leaching of pulverized silica. A series of studies has been carried out on the effect of leaching silica powder as a function of the leaching time at the constant temperature of $80^{\circ}C$ in oxalic acid, aqua regia, and two mixed acids of HF/HCl, $HF/HNO_3$. The impurities of silica and leachantes were measured by neutron activation analysis (NAA), inductively coupled plasma atomic emission spectrometry (ICP-AES), atomic absorption spectrometry, x-ray fluorescence (XRF) method and wet analysis (WA). Certain metals, such as sodium, calcium, iron, aluminium and titanium, have been found in concentrations of hundreds or even thousands of mg/kg. Comparison of purification processes of silica and analytical methods of impurities in the silica was conducted in this study.

• Korean Journal of Poultry Science
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• v.24 no.2
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• pp.73-83
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• 1997

This study was conducted to investigate the influence of dietary $\omega$-fatty acids on fatty acids composition and storage characteristics in meat samples of spent hens. Spent hens were randomly assigned to one of the four dietary treatments : 1) Control (commercial feed), 2) T1 (commercial feed supplemented with 10% olive oil, 3) T2 (commercial feed with 10% canola oil), and 4) T3 (commercial feed with 10% sardine oil). They were fed one of the experimental diets for three weeks and slaughtered. The meat samples were stored at 4 ${\pm}$ 1 ˚C The storage characteristics and fatty acid contents were analyzed for meat samples stored over a period of 1, 3, 5, 7 and 9 days. The pH of all treatments significantly increased during the storage periods(P<0.05). The per-oxide values (POV) of all treatments were significantly increased up to 5 days ; after that the POV decreased significantly (P<0.05). The POV of treated groups were significantly higher than those of the Control in the thigh meat(P<0.05). The TBARS showed the highest POV among all treatments. Although the breast meat tended to he lower in POV than the thigh meat, no significant difference was detected between the two meats. The TBARS(thiobarbituric acid reactive substances) of all treatments were significantly increased as the storage period extended(P<0.05). After 3 days, the TB ARS of oil-treated groups were aignificantly higher than that of the Control (P<0.05). The T3 showed the highest TBARS among all treatments (P<0.05). The TBARS of the breast meat was lower than that of the thigh, but no statistical difference was found be- tween them. The unsaturated fatty acid content of the breast and thigh meats in all treatments were slightly decreased as the storage period extended. The oleic acid was higher in Ti, and the linoleic acid and linolenic acid were higher in T2 than the other treatments. The eicosapentaenoic acid and docosahexaenoic acid were higher in T3 than the other treatments. The unsaturated fatty acid contents of the breast meat were slightly lower than those of the thigh meat. The n-6 fatty acid contents of the breast and thigh meats were slightly increased as the storage periods ex-tended. The n-3 fatty acid content of T3 was the highest among all treatments. The n-6 fatty acid content of breast meat was lower than that of thigh meat. The n-6 fatty acid content of the breast meat was slightly lower than that of the thigh meat.

• Korean Journal of Poultry Science
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• v.31 no.3
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• pp.165-170
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• 2004

The objective of this study was to evaluate the carcass and meat quality of broiler chicken when slaughtered after treating with different source of grain(T1, 100% corn; T2, 50% corn + 50% brown rice; T3, 100% brown rice) in broiler diet. The carcass weight was decreased when feeding level of rice increased. The yield of breast was higher in T2(18.6%) than T1(17.3%) and T3(l7.9%). The L values(L *) and b values(b*) in meat color were decreased as the feeding level of rice increased when compared to T1(P < 0.05). Warner-Bratzler shear force(WBS) values were higher in T2 and T3 compared to T1. Cooking loss(%) was increased for T2(23.49%) and T3(24.50%) compared to T1(22.90%). In fatty acid composition, linoleic acid(C18:2, n6) contents were significantly lower in T2(31.89%) and T3(27.89%) when compared to TI(33.21%)(P < 0.05), and the total contents of unsaturated fatty acids(UFA) were 76.85%(T1), 77.22%(T2), or 75.49%(T3). The ratio of n6/n3 was decreased as the level of rice increased in the feed(T1 19.89%, T2 17.73%, and T3 17.01%). In conclusion, the meat quality was not significantly different between T1 and T2 from the results of carcass weight, meat color, WBS, and fatty acid composition; therefore, brown rice can be substituted for 50% of corn in the broiler diets.

• Korean Journal of Materials Research
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• v.15 no.6
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• pp.413-418
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• 2005

Perovskite $Pb(Ni_{1/3}Nb_{2/3})O_3-Pb(Zr,Ti)O_3[PNN-PZT]$ ceramics were synthesized by conventional ceramic processing technique. In order to modify piezoelectric properties for sensor application in this system, NiO addition was considered to provide $Ni^{+2}$ as an acceptor, which was known to occupy with B site in the structure. The effect of NiO addition up to $8\;mol\%$ on the following piezoelectric properties as well as sintering properties was investigated. When NiO added more than $1\;mol\%$, average grain size was decreased and second phase was found to form. Moreover, the second phase caused decrease in relative dielectric constant $(\varepsilon_{33}T/\varepsilon0)$, electro-mechanical coupling factor $(k_p)$, and piezoelectric charge constant $(d_{33})$, while increasing mechanical quality factor $(Q_m)$. When $1\;mol\%$ NiO was added, density, dielectric properties and piezoelectric properties were abruptly increased.

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.583-592
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• 2005

This experiment was conducted to determine the effects of dietary copper levels on performance, carcass characteristics, and economical analysis in Hanwoo steers. Fifteen Hanwoo steers weighing about 300kg were randomly allotted into one of three treatments. The three treatments consisted of Control(7mg Cu/kg feed), TI(12mg Cu/kg feed) and TII(17mg Cu/kg feed). Copper was formulated with concentrate from copper sulfate($CuSO_4$) and animals were fed the diets supplemented with copper from 300kg untill about 630 kg of body weight. Dietary copper levels did not affect daily weight gain, feed intake and feed efficiency during the whole feeding period. Dressing percentage, rib eye area and backfat thickness were not different between animals fed the diets supplemented with copper. Animals fed the diets supplemented with copper received the same B grade in yield grade. Animals fed the diets supplemented with copper received same marbling score. Beef color, fat color, texture and maturity were not affected by Cu supplementation in diet. Animals received the same first grade between treatments in quality grade. Animals fed the diet supplemented with 12mg of copper per kg diet was higher in profit by 13.3% than animals fed the control diet. According to these results, it may be concluded that performance, yield and quality grade were not affected by the Cu levels of 7 to 17mg per kg feed but crude income was enhanced when Hanwoo steers were fed the diet containing 12mg Cu/kg feed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.361-367
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• 1984

In previous paper(Lee et al., 1984), preparation formula and processing conditions of the fish meat (mackerel) paste using dielectric heating were described, that included the proper shape and size of product and the conditions of dielectric heating, hot air dehydration, and heating with electric heater to yield the minimum expansion and case hardening during heating and to controll the final rater activity of 0.86 to 0.83 accompanying with a complete reduction of viable cells and good texture. In present study, changes in VBN, pH, total plate count, water activity, texture, the loss of available lysine, color indexes, TBA value, and the content of TI were determined to assess the quality stability and shelf-life of the product during the storage for 35 days at $5^{\circ}C\;and\;25^{\circ}C$, respectively. And the effect of vacuum sealing and hot water treatment before storage on the storage stability of product was also mentioned. As the product was vacuum packed in K-flex film bag, heat treated in boiling water for 6 minutes, and stored, water activity was maintained 0.86 to 0.84 for 35 days regardless of storage temperature, and the increase of total plate count was negligible in case of $5^{\circ}C$ storage while tended to gain slightly after 25 days at $25^{\circ}C$ storage. Changes in VBN was also minimum with an increase of 1.5 mg/100g at $5^{\circ}C$ and 7.0mg/100g at $25^{\circ}C$, but in case of unpacked sample, it was 24.5mg/100g at $5^{\circ}C$ and 42.4 mg/100g at $25^{\circ}C$ even after 7 days. In textural property hardness tended to increase after 28 days and folding test score was down to A or B from AA grade. The loss of available lysine was $7.5\%\;at\;5^{\circ}C$ and $17.0\%\;at\;25^{\circ}C$ but brown color was not deeply developed as the color index score indicated. TBA value was not increased at $5^{\circ}C$ while it tended to increase rapidly after 30 days at $25^{\circ}C$. Changes in TI content was not obvious except that it showed a tendency of increase at the end of storage as well as in the change of lysine and TBA value. It is concluded from the results that the quality of the product, pasteurized and water activity controlled by dielectric heating, and vacuum packed in K-flex film would be stable for more than 35 days at $5^{\circ}C$ and at least 25 days even at room temperature.

• Magazine of the Korea Concrete Institute
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• v.9 no.3
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• pp.127-135
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• 1997

In this study, the wedge splitting tcst (WST) was carried out for the fatigue wack growth behavior of concrete. Selected test variables were concrete compressive strength of 28, 60 and 118 MI%, and stress ratio with 2 levels (6. 13%). In oder to make the designed stress ratio, the maximum and thr minimum fatigue loading level were 75-85% and 5- 10% of ultimate static load, respectively. Fatigue testing was preceded by crack mout.h opening displacement (CMOI)) compliance calibration tcst, and then the fatigue crack growth was computed by crack lcngth vs. (lMOI) compliance relations acquisited by the CMOD compliance calibration technique. To evaluate thc validity of CMOD compliancc calibration techniquc, the crack length p~mlicted by this method was cornpard with the crack length by linear elastic fracture mechanics(LEFIbl) and dyeing test. On the basis of the experimental results, a LRFhl-based c.mpirica1 model for f'at,igue crack growth rate(da/dN-AKI relationships) was presented. The fat,igut. crack growth ratc increased with the strength of concwtc. It appcars that t.he da/tiN-AKI relationships was influenced by stress ratio, however, the effect is diminished with an increase of strength. The comparisons between CblOl) compliance calibration technique anti the other. methods gave the validity of' ('MOD compliance calibration technique for the LZXT.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.84-84
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• 2012

소자가 고집적화 됨에 따라, 비저항이 낮고 electro migration (EM), Stress Migration (SM) 특성이 우수한 구리(Cu)를 배선재료로서 사용하고 있다. 그러나, 구리는 Si과 $SiO_2$의 내부로 확산이 빠르게 일어나, Si 소자 내부에 deep donor level을 형성하고, 누설 전류를 증가시키는 등 소자의 성능을 저하시킬 수 있는 문제점을 가지고 있다. 그러나, electroplating 을 이용하여 증착한 Cu 박막은 일반적으로 확산 방지막으로 쓰이는 TiN, TaN, 등의 물질과의 접착 (adhesion) 특성이 나쁘다. 따라서, Cu CMP 에서 증착된 Cu 박막의 벗겨지거나(peeling), EM or SM 저항성 저하 등의 배선에서의 reliability 문제를 야기하게된다. 따라서 Cu 와 접착 특성이 좋은 새로운 확산방지막 또는 adhesion layer의 필요성이 대두되고 있다. 본 연구에서는 이러한 Cu 배선에서의 접착성 문제를 해결하고자 Metal organic chemical vapor deposition (MOCVD)을 이용하여 제조한 코발트(Co) 박막을 $Cu/TaN_x$ 사이의 접착력 개선을 위한 adhesion layer로 적용하려는 시도를 하였다. Co는 비저항이 낮고, Cu 와 adhesion이 좋으며, Cu direct electroplating 이 가능하다는 장점을 가지고 있다. 하지만, 수소 분위기에서 $C_{12}H_{10}O_6(Co)_2$ (dicobalt hexacarbonyl tert-butylacetylene, CCTBA) 전구체에 의한 MOCVD Co 박막의 경우 탄소, 산소와 같은 불순물이 다량 함유되어 있어, 비저항, surface roughness 가 높아지게 된다. 따라서 구리 전착 초기에 구리의 핵 생성(nucleation)을 저해하고 핵 생성 후에도 응집(agglomeration)이 발생하여 연속적이고 얇은 구리막 형성을 방해한다. 이를 해결하기 위해, MOCVD Co 박막 증착 시 수소 반응 가스에 암모니아를 추가로 주입하여, 수소/암모니아의 분압을 1:1, 1:6, 1:10으로 변화시켜 $Co/TaN_x$ 박막의 특성을 비교 분석하였다. 각각의 수소/암모니아 분압에 따른 $Co/TaN_x$ 박막을 TEM (Transmission electron microscopy), XRD (X-ray diffraction), AES (Auger electron spectroscopy)를 통해 물성 및 조성을 분석하였고, AFM (Atomic force microscopy)를 이용하여, surface roughness를 측정하였다. 실험 결과, $Co/TaN_x$ 박막은 수소/암모니아 분압 1:6에서 90 ${\mu}{\Omega}-cm$의 낮은 비저항과 0.97 nm 의 낮은 surface roughness 를 가졌다. 뿐만 아니라, MOCVD 에 의해 증착된 Co 박막이4-6 % concentration 의 탄소 및 산소 함량을 가지는 것으로 나타났고, 24nm 크기의 trench 기판 위에 약 6nm의 $Co/TaN_x$ 박막이 매우 균일하게 형성된 것을 확인 할 수 있었다. 이러한 결과들은, 향후 $Co/TaN_x$ 박막이 Cu direct electroplating 공정이 가능한 diffusion barrier로서 성공적으로 사용될 수 있음을 보여준다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.346-346
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• 2007

압전세라믹 재료는 현재 압전 변압기, actuator, transducer, sensor, speaker 등에 광범위하게 이용이 되고 있다. 이 중에서 압전세라믹 소결체를 이용한 스피커의 제조는 가공이 까다롭고, 대형의 크기로 제작 시 소자가 깨지는 등의 많은 제약을 받고 있으며, 저음 특성이 떨어져 응용 범위가 한정되어 있다. 따라서 최근에는 이러한 단점을 극복하기 위하여 세라믹/고분자 복합체를 이용한 필름 스피커를 제작하고자 시도하고 있다. 이러한 세라믹/고분자 0-3형 압전 복합체를 이용할 경우, 제품의 경량화를 실현할 수 있고, 크기나 환경의 영향을 거의 받지 않으므로, 고기능성 스피커로의 응용에 적합할 것으로 보인다. 따라서 본 연구에서는 PZT계의 세라믹와 PVDF, PVDF-TrFE, Polyester, acrylic resin 등의 여러 고분자 물질과의 복합체를 제조하여 압전특성을 평가하였다. 본 실험은 먼저 $(Pb_{1-a-b}Ba_aCd_b)(Zr_xTi_{1-x})_{1-c-d}(Ni_{1/3}Nb_{2/3})_c(Zn_{1/3}Nb_{2/3})_dO_3$ (이하 PZT라 표기)의 최적화 조성을 선택하여, $1050^{\circ}C$에서 소결된 분말을 48시간 ball milling방법 로 약 $1{\mu}m$ 크기로 분쇄하였다. 고분자 물질들은 알맞은 용제들을 선택하여 녹였다. 그 다음 소결된 PZT분말과 고분자를 50:50, 60:40, 65:35, 70:30등의 무게 분율로 혼합하고, 분산제, 소포제 등을 첨가하여 3단 roll mill을 이용하여 충분히 분산시켜 페이스트 (Paste)를 제조하였다. 제조된 페이스트를 ITO가 코팅된 PET필름 위에 스크린 프린팅 법을 사용하여 인쇄하여 $120^{\circ}C$에서 5분간 건조하였다. 코팅된 복합체의 두께는 약 $80{\mu}m$ 정도로 측정되었다. Ag 페이스트를 이용한 상부 전극 형성에도 스크린 프린팅 법을 적용하였다. 이를 $120^{\circ}C$에서 4 kV/mm의 DC 전계로 분극 공정을 수행한 후 전기적 특성을 평가하였다. 유전특성을 조사하기 위해서 LCR meter (EDC-1620)를 사용하였고, 시편의 결정구조는 XRD (Rigaku; D/MAX-2500H)을 통해 분석하였으며, 전자현미경(SEM)을 이용하여 미세구조를 분석하였다. 압전 전하상수$(d_{33})$ 값은 APC 8000 모델을 이용하여 측정하였다. PZT의 혼합비가 증가할수록 비유전율 및 압전 전하 상수 등의 전기적 특성이 증가되었다. 또 여러 고분자 물질 중에서 PVDF-TrFE 수지가 가장 우수한 특성을 보였다. 이는 PVDF-TrFE 수지가 압전성을 나타내기 때문인 것으로 판단되었다.

• Journal of Physiology & Pathology in Korean Medicine
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• v.35 no.2
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• pp.56-63
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• 2021

This study was conducted to find a candidate prescription with anti-inflammatory efficacy of 7 herbal prescriptions known to be effective in atopic dermatitis and sleep disorders in Korean medicine. The anti-inflammatory of the 7 herbal prescriptions extracts were evaluated by ELISA assay and Western blot assay. 7 herbal prescriptions, Seongyutang(SU), Danseontoetang(DST), Sotosajahwan(ST), Jisiljagyagsan(JJ), Seokchangpo(SCP), Wiryeongseon(WLS), Gogojohwan(GGJ) 30 % EtoH extract was used for in vitro experiments. In TNF-α + IFN-γ(TI) stimulated HaCaT cells, all 7 herbal prescriptions reduced TARC and MDC production, and JJ strongly reduced TARC and MDC production at 100 ㎍/ml concentration. SCP strongly reduced MDC production at 10 ㎍/ml and 100 ㎍/ml concentration. In addition, in substance P(SP)/CRH stimulated HMC-1 cells, JJ strongly inhibited VEGF production at both 10 and 100 ㎍/ml concentrations. In LPS/CRH stimulated Raw264.7 cells, all 7 herbal prescriptions significantly inhibited TNF-α. PMA + Ionomycin(PI)/CRH stimulated EL4 cells, SU significantly reduced IL-4 production at both concentrations of 10 and 100 ㎍/ml. WLS significantly reduced IL-17 production at both concentrations of 10 and 100㎍/ml. This suggests that 7 herbal prescriptions have anti-inflammatory effects by reducing inflammatory cytokines in keratinocytes, mast cells and macrophages caused by inflammation. Therefore, it is expected that 7 herbal prescriptions that are effective for sleep disorders and atopic dermatitis can be used as therapeutic materials for sleep disorders and diseases associated with atopic dermatitis.