• Title/Summary/Keyword: low alpha

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Mechanical and Tribological Properties of $\alpha$-Sialon/SiC Whisker Composites ($\alpha$-Sialon/SiC Whisker 복합재료의 기계적 물성 및 마모 특성 연구)

  • 이병하;김인섭;이경희
    • Journal of the Korean Ceramic Society
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    • v.30 no.10
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    • pp.785-790
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    • 1993
  • Sialon ceramics are presently seen as promising materials with high hardness, strength, fracture toughness and corrosion resistance for friction and wear applications. The objective of present work is to improve of mechanical properties and wear resistance of $\alpha$-Sialon(x=0.4) by addition of SiC whisker. $\alpha$-sialon(x=0.4)/SiC whisker composites were obtained by hot-isostatic pressing at 173$0^{\circ}C$ for 1 hour under 1757Kg/$\textrm{cm}^2$ N2 pressure after pressureless sintering the mixture of Si3N4, Y2O3, AlN at 1780~180$0^{\circ}C$ for 3~5 hours in N2 atmosphere. As the amount of SiC whisker content increased, relative density and hardness were decreased, however fracture toughness, bending strength and tribological properties were improved. Tribological properties of $\alpha$-Sialon/15 vol% SiC whisker composite were improved in spite of its low mechanical properties.

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Antioxidative Effects of Some Antioxidants according to Storage Conditions of Cooked Soybean Oil (가열유지의 저장조건에 따른 일부 항산화제의 항산화 효과)

  • Yoon, Soo-Hong;Lee, Myoune-Jin;Park, Byoung-Yoon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.17 no.2
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    • pp.158-163
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    • 1988
  • The changes of the physico-chemical properties and fatty acid compositions of cooked soybean oil, 30 min at $180{\pm}5^{\circ}C$, were investigated to compare the antixidative effects of some antioxidants such as BHA, ${\alpha}-tocopherol$ and sesamol according to various storage conditions(room temperature, room temperature with a air tight in the dark and low temperature with air tight) for 4 weeks. The order of antioxidative effects according to different storage conditions was low temperature with air tight, room temperature with air tight in the dark and room temperature. Acid values, peroxide values and carbonyl values of soybean oil stored under low temperature with air tight after ${\alpha}-tocopherol$ treatment were similar to those of soybean oil stored under room temperature after BHA treatment. The relative contents of linoleic acid and linolenic acid decreased during storage, wheras those of oleic acid and palmitic acid increased. The contents of linoleic acid in soybean oil treated with ${\alpha}-tocopherol$ and BHA under low temperature with air tight storage were $53.61{\sim}50.29%$ and $53.78{\sim}50.68%$, respectively. These contents were very high in comparison with those in untreated oil under room temperature storage, $52.09{\sim}43.96%$.

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Treatment and Survival in Patients with Chronic Myeloid Leukemia in a Chronic Phase in West Iran

  • Payandeh, Mehrdad;Sadeghi, Masoud;Sadeghi, Edris
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.17
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    • pp.7555-7559
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    • 2015
  • Background: CML includes 30% of all leukemias, and occurs from childhood to old age. The present study was a retrospective analysis of chronic phase CML patients registered to a Hematology Clinic in Kermanshah, Iran, with checking of treatment options. Materials and Methods: Between 2002 and 2014, 85 CML patients referred to our hematology clinic were enrolled in our study. We surveyed age, sex, B-symptoms, splenomegaly, Sokal score, Hasford score, treatment and survival in all patients. Philadelphia chromosome analysis was conducted for each patient by conventional cytogenetics. We compared treatment in the patients with three drugs, imatinib, hydroxyurea (HU) and interferon alpha (IFN-${\alpha}$). Results: The mean age of the patients at diagnosis was $47.5{\pm}14.5years$ (range, 23-82 years), with 43 (50.6%) being male. Some 13 (15.3%) were referred to our clinic for the first time with B-symptoms and 44 patients (51.8%) had splenomegaly. The Sokal score for 77 (90.6%) was low, 4 (4.7%) was intermediate and 4(4.7%) was high, but Hasford (Euro) scores for all patients were low. The 5-year survival rate for treated patients with imatinib, imatinib plus HU and imatinib plus HU plus IFN-${\alpha}$ was 90.5%, 81.1% and 55.6%, respectively Conclusions: The results show that imatinib therapy alone provides better survival in CML patients compared to HU or IFN-${\alpha}$. Combinations of IFN-${\alpha}$ and/or HU with imatinib probably reduce survival.

Heart Response Effect by 1/f Fluctuation Sounds for Emotional Labor on Employee (1/f 수준 별 음악 자극이 감정 노동 종사자의 심장 반응에 미치는 효과)

  • Jeon, Byung-Mu;Whang, Min-Cheol
    • Science of Emotion and Sensibility
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    • v.18 no.3
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    • pp.63-70
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    • 2015
  • This study identified heart response of participants while listening to sounds which have 1/f fluctuations with exponent ${\alpha}$ gradient. The participants were engaged in emotional stress work. Prior studies related to 1/f fluctuation sound have reported that sound source can alleviate psychological and physiological state of users. Subjects of this study were exposed to sound with three levels of ${\alpha}$ gradient. Heart response of subjects were measured with Photoplethysmography(PPG) sensor simultaneously. The dependent variables of this study were beat per minute(BPM), very low frequency percent of pulse rate variability (VLF percent), the standard deviation of all normal RR intervals (SDNN), and high frequency power(HF power). Subject showed arousal response when exposed to sound with exponent ${\alpha}$ gradient of 3 whereas the sound with exponent ${\alpha}$ gradient of 1 and 2 resulted in relax effect. The characteristic of 1/f fluctuation sounds can be applied to alleviate stress for employers under emotional labor.

The preparation of $alpha-sexithiophene$ thin films by organic molecular beam deposition method and their characteristics (유기 분자선 증착법(OMBD)에 의한 $alpha-sexithiophene$ 박막의 제조와 특성)

  • 권오관;김영관;손병청;박주상;변대현;신동명;최종선
    • Journal of the Korean Vacuum Society
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    • v.7 no.4
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    • pp.361-367
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    • 1998
  • $\alpha$-Sexithiophene ($\alpha$-6T) thin films were deposited by organic molecular beam deposition (OMBD) technique. The $\alpha$-6T was synthesized and purified by the sublimation method. The thin films of the $\alpha$-6T were deposited under various deposition conditions. The effects of deposition rate, substrate temperature, and vacuum pressure on the formation of these films have been studied. The molecular orientation, crystallinity, and surface morphology of $\alpha$-6T films were investigated with angle-resolved UV/visible absorption spectroscopy, X-ray diffractometry (XRD), and atomic force microscopy (AFM). It was found that the crystalline structure of $\alpha$-6T films was monoclinic and independent uppon substrate temperature, deposition rate, and deposition pressure. On the other hand, the $\alpha$-6T molecules in the film deposited at a low deposition rate, higher substrate temperature, and under a high vacuum tended to be aligned perpendicular to the substrate.

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Low T3 syndrome in Kawasaki disease: Relation to serum levels of tumor necrosis factor-α, interleukin-6 and NT-proBNP (가와사끼병에서의 저 T3 증후군 : 혈청 tumor necrosis factor-α, interleukin-6 및 NT-proBNP 농도와의 관계)

  • Cho, Hye Kyung;Sohn, Jin A;Kim, Hae Soon;Sohn, Sejung
    • Clinical and Experimental Pediatrics
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    • v.52 no.2
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    • pp.234-241
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    • 2009
  • Purpose : We investigated the relationship between thyroid hormone and serum tumor necrosis factor (TNF-${\alpha}$), interleukin (IL-6) and N-terminal fragment of pro-brain natriuretic peptide (NT-proBNP) in patients with Kawasaki disease (KD). Methods : Serum levels of thyroid hormone, TNF-${\alpha}$, IL-6, and NT-proBNP were measured in 52 KD patients in the acute and subacute phase and 10 patients with acute febrile illness (control group). TNF-${\alpha}$ and IL-6 were determined by sandwich enzyme-linked immunosorbent assay (ELISA). Echocardiography was performed to detect coronary artery lesions (CAL) in KD patients. Results : Low $T_3$ syndrome occurred in 63.5% of KD patients. $T_3$ in the acute phase of KD was lower than that in the control. In KD patients, $T_3$ was lowered in the acute phase and elevated in the subacute phase, whereas TNF-${\alpha}$, IL-6 and NT-proBNP were elevated in the acute phase and decreased in the subacute phase. NT-proBNP, and IL-6 were higher in patients with low $T_3$ than in those with normal $T_3$. In addition, $T_3$ inversely correlated with IL-6 and NT-proBNP. Of the 4 patients with CAL, 3 had very low $T_3$. Compared with intravenous immunoglobulin (IVIG)-responsive patients, IVIG-resistant patients had lower $T_3$ and higher IL-6 and NT-proBNP. Conclusion : $T_3$ decreases in the acute phase of KD and normalizes in the subacute phase without thyroid hormone replacement. Low $T_3$ may be partially induced by IL-6 rather than TNF-${\alpha}$, and is strongly associated with high NT-proBNP. $T_3$ in KD may be used for the differential diagnosis, monitoring the activity of the disease, and predicting the severity of inflammation.

Spectral Perturbation of Theta and Alpha Wave for the Affective Auditory Stimuli (청각자극에 따른 세타파와 알파파의 스펙트럼적 반응)

  • Du, Ruoyu;Lee, Hyo Jong
    • KIPS Transactions on Software and Data Engineering
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    • v.3 no.10
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    • pp.451-456
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    • 2014
  • The correlations between electroencephalographic (EEG) spectral power and emotional responses during affective sound clip listening are important parameters. Hemispheric asymmetry in prefrontal activation have been proposed in two decades ago, as measured by power value, is related to reactivity to affectively pleasure audio stimuli. In this study, we designed an emotional audio stimulus experiment in order to verify frontal EEG asymmetry by analyzing Event-related Spectral Perturbation (ERSP) results. Thirty healthy college male students volunteered the stimulus experiment with the standard IADS(International Affective Digital Sounds) clips. These affective sound clips are classified in three emotion states, high pleasure-high arousal (happy), middle pleasure-low arousal (neutral) and low pleasure-high arousal (fear). The analysis of the data was performed in both theta (4-8Hz) and alpha (8-13Hz) bands. ERSP maps in the alpha band revealed that there are the stronger power responses of high pleasure (happy) in the right frontal lobe, while the stronger power responses of middle-low pleasure (neutral and fear) in the left frontal lobe. Moreover, ERSP maps in the theta band revealed that there are the stronger power responses of high arousal (fear and happy) in the left pre-frontal lobe, while the stronger responses of low arousal (neutral) in the right pre-frontal lobe. However, the high pleasure emotions (happy) can elicit greater relative right EEG activity, while the low and middle pleasure emotions (fear and neutral) can elicit the greater relative left EEG activity. Additionally, the most differences of theta band have been found out in the medial frontal lobe, which is proved as the frontal midline theta. And there are the strongest responses of happy sounds in the alpha band around the whole frontal regions. These results are well suited for emotion recognition, and provide the evidences that theta and alpha powers may have the more important role in the emotion processing than previously believed.

Effects of Low Fat Diet and Saturated Fat Supplementation on the Immune Status of BALB/c Mouse (저지방식이와 포화지방 첨가 식이가 BALB/c 마우스의 면역기능에 미치는 영향)

  • 박진순
    • Journal of Nutrition and Health
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    • v.26 no.5
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    • pp.578-585
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    • 1993
  • This study was performed to investigate effects of low fat diet and saturated fat supplementation on the function of the immune system. Forty male BALB/c mice average-weighing 15g were divided into two dietary groups: 0.7% safflower oil group and 4.3% beef tallow & 0.7% safflower oil group. Results are as follows; 1) Food intake, body weight, organ weight, agglutination test, differential white cell count and histological examination of spleen were not different in two dietary groups during the experimental period. 2) Delayed-type hypersensitive test of the mice fed 4.3% beef tallow & 0.7% safflower oil was significantly higher than that of the mice fed 0.7% safflower oil ($\alpha$=0.05). 3) Plaque forming cell was significantly reduced at 10th week compared to 7th week in both groups($\alpha$=0.05). Although there was no significant difference between two groups. 0.7% safflower oil groups showed slightly higher plaque forming cell than 4.3% beef tallow & 0.7% safflower oil group.

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Study on the Optimal Shape of Low Noise, New Concept Fan for Refrigerator (냉장고용 저소음 신형상홴의 최적 형상에 관한 연구)

  • 정용규;김창준;백승조;전완호
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.645-650
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    • 2002
  • In this paper, new concept, low noise axial fan was developed. The fan was designed to operate at high-pressure condition inside the refrigerator. This fan - we call it Alpha fan - has small turbo blades at trailing edge of axial fan. These turbo blades make alpha fan operate at high pressure and low noise condition. In order to find out the optimal value of design parameters, 6-sigma method was used. The design parameters are ratio between inner and outer diameter, Height, Install angle and Install position of turbo blade. Optimal value of turbo blade was found out and the noise generated from this fan is reduced about 3dB(A).

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The Influence of Radiation Trapping on the Metastable Population Density and Applications to Low-pressure Plasma

  • Lee, Yeong-Gwang;O, Se-Jin;Jeong, Jin-Uk
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.245-246
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    • 2011
  • Emission lines ratios were used for diagnostics of and excited level densities in low-temperature plasmas. In this work, an optical emission spectroscopy (OES) was used to determine the electron temperature and metastable level densities in low-pressure inductively coupled plasma. The emission spectroscopy method was based on a simple collisional-radiative model. The selected lines of the Ar(4p to 4s) were influenced by the radiation trapping at relatively high pressures where the plasma become optically thick. To quantify this effect, a pressure dependence factor ${\alpha}$(P) was derived by using corrections for the measured intensities. It was found that the lower metastable level densities were obtained when ${\alpha}$(P) increased with the increasing discharge pressure. The effect of non-Maxwellian electron energy distribution functions (EEDFs) on the metastables was also presented and discussed.

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