• Title/Summary/Keyword: AH-1

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A STUDY ON THE PHYSICAL PROPERTIES OF ROOT CANAL SEALERS (근관충전용 실러의 물리적 성질에 관한 연구)

  • Chang, Young-In;Choi, Ho-Young
    • Restorative Dentistry and Endodontics
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    • v.20 no.1
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    • pp.142-151
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    • 1995
  • The purpose of this study was to compare and estimate the physical properties of five root canal sealers classified Calciobiotic root canals sealer as calcium hydroxide based sealer, Apatite root sealer type II as calcium phosphate based sealer, AH-26 as resin based sealer, Canals and Pulpdent root canals sealer as zinc oxide eugenol based sealer. The author investigated dimensional change and flow rate of canal sealers, diametral tensile strength and shear bond strength of sealers to dentin to evaluate the physical properties on affect of complete obturation of root canal and performed the total 100 specimens of each 25 sealers under the condition of root temperature according to manufacturer's instructions. All specimens were stored at $37{\pm}1^{\circ}C$ in 100 % relative humidity. A microscope for measurement of micro distance is used for the dimensional change test and evacuation methods using vaccum were used for the flow rate test. The result differed by the storage time measured on the tests of diametral tensile strength and shear bond strength to dentin. The following results were obtained ; 1 On the test of dimensional change, Canals and Pulpdent expanded slightly, AH-26 and Apatite showed the severe shrinkage after 48 hours. 2. AH-26 and Apatite were the excellent with each 24.59mm, 31.19mm after 3 minutes in the aspect of flow property. 3. On the diametral tensile strength, Calciobiotic root canals sealer showed the highest strength with 27.13kg/$cm^2$ after 48 hours, Apatite root sealer type II showed highest strength with 84.57kg/$cm^2$ after 120 hours. 4. On the shear bond strength to dentin, AH-26 was most excellent with 55.73kgf/$cm^2$ after 24 hours and with 134.71kgf/$cm^2$ after 120 hours.

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A Clothing Ergonomics Studyon the Seelve form Variation and the Clothing Pressure Variation According to Arm Movement (동작에 따른 상지형태 변화와 의복에 대한 피복인간공학적 연구(I))

  • Kim Hae-Kyung;Kim Soon-Ja;Cho Jung Mee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.12 no.2 s.27
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    • pp.237-248
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    • 1988
  • To access the appropriate height of sleeve cap which is required for the basic sleeve pattern according to arm movements, plaster gypsum experiment was performed. Arm movements were 5types ($0^{\circ},\;45^{\circ},\;90^{\circ},\;135^{\circ},\;180^{\circ}$) to the vertical directions in the front. The appropriateness of the pattern was analyzed by measuring clothing pressure. The results obtained were as follows: 1. Increasing the movement angle, sleeve width increased but height of sleeve cap and armhole girth decreased. 2. Increasing the movement angle, the acromion moved to the front part of bodice. 3. On the basis of the result of the height of sleeve cap, the $\frac{AH}{4} +2.5cm$ sleeve basic 4 pattern is suitable for the direction $M_1(0^{\circ}),\;M_2(45^{\circ})$, and the $\frac{AH}{5}$sleeve basic pattern is suitable for the direction $M_3(90^{\circ}),\;M_4(135^{\circ})$, and $M_5(180^{\circ})$. 4. As the movement angle and height of sleevecap increased, the part which receive high pressure increased and the difference between the hightest and the lowest clothing pressure increased. 5. By the variation of movement angle and height of sleevecap, clothing pressure of upperarm was affected more than that of shoulder blade. 6. The clothing pressure of upperarm and shoulder blades were more affected by the height of sleeve cap than the ease of breast area. 7. Considering the clothing pressure of various arm movement, the most appropriate height of sleeve cap for $M_1(0^{\circ}),\;M_2(45^{\circ})$ positions was to use the $\frac{AH}{4}$+2.5cm, and for $M_3(90^{\circ}),\;M_4(135^{\circ})$, and $M_5(180^{\circ})$, was $\frac{AH}{5}$.

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Electrochemical Characteristics of Si/SiO2/C Anode Material for Lithium-Ion Battery According to Addition of CNT and CNF Compounds (CNT와 CNF 복합첨가에 따른 Si/SiO2/C 음극활물질의 전기화학적 특성)

  • Seo, Jin-Seong;Yoon, Sang-Hyo;Na, Byung-Ki
    • Korean Chemical Engineering Research
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    • v.59 no.1
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    • pp.35-41
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    • 2021
  • Silicon is a promising next-generation anode material for lithium-ion battery, and it has been studied for commercialization due to the high theoretical capacity. However, it has problems of the volume change during charge-discharge and the poor electrical conductivity. To solve these problems, formation of SiO2 and carbon coating on the surface of silicon crystal were performed to protect the side reaction and enhance the electrical conductivity of silicon. CNT and CNF were also added to mitigate the volume change and increase the conductivity. Physical properties of asprepared samples were analyzed by XRD, SEM, and EDS. Electrochemical characteristics were investigated by electrical conductivity measurement, EIS, CV and cycle performance test. (Si/SiO2/C)+CNT&CNF showed high electrical conductivity and low charge-transfer resistance, and the capacity was 1528 mAh/g at 1st cycle and 1055 mAh/g at 50th cycle with 83% capacity retention.

Effective adjacent baggage split method of Baggage Position Control System to prevent double loading of baggage

  • Song, Jae-Won;Kim, Dong-Chul
    • Journal of the Korea Society of Computer and Information
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    • v.23 no.3
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    • pp.33-40
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    • 2018
  • In this paper, we propose a method to effectively split the adjacent baggage that is moving on high speed conveyor of airport. The proposed method calculate the Angle Histogram(AH) that inspects background pixels within radius r based on the center point of the adjacent baggage. After that, the adjacent baggage is segmented by finding split angles at the AH. We also improved the split quality of adjoining baggage by repeatedly correcting the center point to correctly split adjacent baggage of asymmetric size. And the calculation time of AH is reduced about 1/3 by using the symmetry property of the circle. Experiments have shown that 93% of all adjacent baggage images are correctly segmented and the proposed method is effective.

The Effect of Real-time Ultrasound Imaging Feedback during Abdominal Hollowing in Four Point Kneeling to Healthy Men

  • Park, Du-Jin
    • The Journal of Korean Physical Therapy
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    • v.22 no.6
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    • pp.1-6
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    • 2010
  • Purpose: This study investigated the effects of visual feedback during abdominal hollowing (AH) in four point kneeling position, using real-time ultrasound imaging through measurement of the changes in the thickness of transversus abdominis (TrA), internal abdominal oblique (IO), and external abdominal oblique (EO). Methods: The subjects of this study were 32 healthy males who were divided intothe experimental group of 16 subjects and the control group of 16 subjects. The real-time ultrasound feedback was applied to the experimental group while they were educated on the AH exercise in four point kneeling whereas only general education and training were given to the control group. After the training, the changes in the thickness of abdominal muscles during AH in four point kneeling were compared between the experimental group and the control group. Results: The differences of the changes in the thickness of TrA and EO between the two groups were statistically significant. Conclusion: The experimental group experienced a higher increase in the thickness of TrA than the control group while the thickness of IO and EO of the experimental.

Effects of Thermomechanical Treatment on 7075-Al Alloy (7075-Al 합금에 대한 가공 열처리 효과에 관한 연구)

  • Choi, S.C.;Kang, C.S.
    • Journal of Korea Foundry Society
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    • v.1 no.2
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    • pp.10-18
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    • 1981
  • In this paper tensile strength and fatigue propagation rate were investigated by aging treatment $(T_6)$ and thermomechanical treatment (TMT) of 7075-Al Alloy specimen. The results of teat showed that TMT improved tensile strength and fatigue crack propagation due to bomogenization of microstructure. In TMT, the results of comparison between T-H' AHA and T-AHA and $T-AH{\cdot}{\cdot}{\cdot}$and $T-HA{\cdot}{\cdot}{\cdot}$were showed that T-AHA and $T-AH{\cdot}{\cdot}{\cdot}$treatments, after solution treatment, which are aging treated before rolling have higher tensile strength. Our investigation on high temperature stability at the Specimen for $T_6$, T-AHA, $T-AH{\cdot}{\cdot}{\cdot}$treatments resulted in rapid reduction of tensile strength over $150^{\circ}C$, but the reduction of tensile strength for specimen of TMT was smoothed than $T_6$.

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Suppression of CYP1A1 Expression by Naringenin in Murine Hepa-1c1c7 Cells

  • Kim, Ji-Young;Han, Eun-Hee;Shin, Dong-Weon;Jeong, Tae-Cheon;Lee, Eung-Seok;Woo, Eun-Rhan;Jeong, Hye-Gwang
    • Archives of Pharmacal Research
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    • v.27 no.8
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    • pp.857-862
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    • 2004
  • Naringenin, dietary flavonoid, is antioxidant constituents of many citrus fruits. In the present study, we investigated the effect of naringenin on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-inducible CYP1 A 1 gene expression in mouse hepatoma Hepa-1c1c7 cells. Naringenin alone did not affect CYP1A1-specific 7-ethoxyresorufin O-deethylase (EROD) activity. In contrast, the TCDD-inducible EROD activities were markedly reduced upon concomitant treatment with TCDD and naringenin in a dose dependent manner. TCDD-induced CYP1A1 mRNA level was also markedly suppressed by naringenin. A transient transfection assay using dioxin-response element (DRE)-linked luciferase and electrophoretic mobility shift assay revealed that naringe-nin reduced transformation of the aryl hydrocarbons receptor(AhR) to a form capable of specif-ically binding to the DRE sequence in the promoter of the CYP1A1 gene. These results suggest the down regulation of the CYP1A1 gene expression by either naringenin in Hepa-1c1c7 cells might be antagonism of the DRE binding potential of nuclear AhR.

An Investigation of the Medicinal Plant Flora of Baek-Ah Island (백아도 약용식물 분포조사)

  • Toh, Sang-Hak
    • Korean Journal of Pharmacognosy
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    • v.1 no.4
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    • pp.133-142
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    • 1970
  • The author has investigated the plant flora of Baek-Ah Island during the period from August 4 to August 10 1970, and found that the flora consist of the plants of coastal, temperature and warm zones. The present report lists 81 families, 190 genera and 235 species of plants, of which 73 families and 170 species are medicinal plants.

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A Study on Electrochemical Characteristics of LiCoO2/LiNi1/3Mn1/3Co1/3O2 Mixed Cathode for Li Secondary Battery (리튬2차전지용 LiCoO2/LiNi1/3Mn1/3Co1/3O2계 복합정극의 전기화학적 특성 연구)

  • Kim Hyun-Soo;Kim Sung-Il;Eom Seung-Wook;Kim Woo-Seong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.1
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    • pp.64-70
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    • 2006
  • In this study, the $LiCoO_2/LiNi_{1/3}Mn_{1/3}Co_{1/3}O_2$ mixed cathode electrodes were prepared and their electrochemical performances were measured in a high cut-off voltage. As the content of $LiNi_{1/3}Mn_{1/3}Co_{1/3}O_2$ increased in a mixed cathode, the reversible specific capacity and cycleability of the electrode enhanced, but the rate capability was deteriorated. On the contrary the rate capability of the cathode enhanced, but the reversible specific capacity and cycleability were deteriorated, increasing the content of $LiCoO_2$ in the mixed cathode. The cell of $LiCoO_2/LiNi_{1/3}Mn_{1/3}Co_{1/3}O_2$ ($50:50 wt\%$) mixed cathode delivered a discharge capacity of ca. 168 mAh/g at a 0.2 C rate. The capacity of the cell decreased with the current rate and a useful capacity of ca. 152 mAh/g was obtained at a 2.0 C rate. However, the cell showed very stable cycleability: the discharge capacity of the cell after 20th charge/discharge cycling maintains ca. 163 mAh/g.

Regulation of CYP 1A1 gene expression by retinoic acid receptor, retinoid X receptor and constitutive androstane receptor in rainbow trout hepatoma cells(RTH 149)

  • Kim, Ji-Sun;Yang, So-Yeun;Seo, Mi-Jung;Sheen, Yhun-Yhong
    • Proceedings of the Korea Society of Environmental Toocicology Conference
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    • 2003.10a
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    • pp.179-179
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    • 2003
  • Exposure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) causes a variety of biological and toxicology effects, most of which are mediated by aryl hydrocarbon receptor (AhR). The ligand-bound AhR as a heterodimer with AhR nuclear translocator (ARNT) binds to its specific DNA recognition site, the dioxin-responsive element (DRE), and it results in increased transcription of CYP1A1 gene. Retinoic acid (RA) regulates the transcription of various genes for several essential functions through binding to two classes of nuclear receptors, the retinoic acid receptor (RAR) and retinoid X receptor (RXR). Constitutive androstane receptor (CAR) also regulates the transcription of gene. In this study, we have examined how RAR, RXR and CAR regulated CYP1A1 in rainbow trout hepatoma cell (RTH 149) using luciferase reporter gene assay system. We did transient transfection with CYP1A1 luciferase reporter gene and treated with TCDD, all-trans RA, 9-cis RA and phenobarbital. Treatment of all-trans RA, 9-cis RA or phenobarbital decreased the TCDD induced transcription of CYP1A1. When we did transient cotransfection with CYP1A1 luciferase reporter gene and RXR, as increase of RXR concentration, the TCDD induced transcription of CYP1A1 was decreased. Transfection with CAR also decreased the TCDD induced transcription of CYP1A1 in RTH 149 cells.

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