• Title/Summary/Keyword: stability period

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Evaluation of Shear Strength at Interface Between Geotextile and Cementitious Binder Materials (시멘트계 결합재가 적용된 지오텍스타일의 접촉면 전단강도 평가)

  • Son, Dong-Geon;Byun, Yong-Hoon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.64 no.1
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    • pp.91-98
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    • 2022
  • Multi-layered geotextile tubes may have problems on its stability when used as cofferdam. This study presents the shear strength characteristics at the interface between geotextiles and a cementitious binder material to improve the stability of the multi-layered geotextile tubes. In this study, two different types of geotextiles are used. After mixing with a rapid setting cement, fly ash, sand, accelerator, and water, the cementitious binder material is prepared at the interface between two geotextile samples and cured under water for a desired period. The specimen is placed on upper and lower direct shear boxes by using clamping systems. A series of direct shear tests for two different geotextiles are performed along the curing time under three vertical stresses. Experimental results show that the shear strength at the interface between the cementitious binder material and geotextiles is greater than that at the interface between two geotextiles. For two types of geotextiles, apparent cohesion occurs at the interface between the cementitious binder material and geotextiles. In addition, the friction angles for any curing time are improved, compared to the interface between two geotextiles. The cementitious binder material suggested for the interface between two geotextiles may be useful for the reinforcement of multi-layered geotextile tubes.

The Effect of Core Stabilization Exercise on Dynamic Balance and Trunk Horizontal Rotation in Adult Men (코어 운동이 성인 남성의 동적 균형과 몸통의 수평 회전에 미치는 효과)

  • Gyeong Hyeon, Jeong;Byounghee, Lee
    • Journal of Korean Physical Therapy Science
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    • v.29 no.4
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    • pp.96-111
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    • 2022
  • Background: This study aims to evaluate the effect of core stabilization exercise on the dynamic balance and horizontal rotation of the trunk in young adult men. Through this study, it is expected that various core stabilization exercises will prevent and treat musculoskeletal disease. Design: Randomized Controlled Trial. Methods: The study subjects were recruited from young adult men in their 20s and 30s living in Seoul, and after the randomized controlled trial, it was divided into an experimental group training core stabilization exercise(n=15) and a control group(n=15). The evaluation methods of this study were modified Star Excursion Balance Test(mSEBT), Functional Reach Test(FRT), and Trunk Rotation Test(TRT). The experimental group performed three sets of crunches and deadbug exercises twice a week for eight weeks, and the control group did not perform any exercises similar to core stabilization exercise during the experimental period. Results: The result of the experiment, the experimental group showed significant improvement in mSEBT(p<.05), FRT(p<.05) and TRT(p<.05). Conclusion: In conclusion, core stabilization exercises improved dynamic balance and horizontal rotation of the trunk. As a result of this study, core stabilization exercise can prevent and treat musculoskeletal diseases even in healthy people.

Voltage Feedback AMOLED Display Driving Circuit for Driving TFT Deviation Compensation (구동 TFT 편차 보상을 위한 전압 피드백 AMOLED 디스플레이 구동 회로)

  • Ki Sung Sohn;Yong Soo Cho;Sang Hee Son
    • Journal of the Semiconductor & Display Technology
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    • v.22 no.4
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    • pp.161-165
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    • 2023
  • This paper designed a voltage feedback driving circuit to compensate for the characteristic deviation of the Active Matrix Organic Light Emitting Diode driving Thin Film Transistor. This paper describes a stable and fast circuit by applying charge sharing and polar stabilization methods. A 12-inch Organic Light Emitting Diode with a Double Wide Ultra eXtended Graphics Array resolution creates a screen distortion problem for line parasitism, and charge sharing and polar stabilization structures were applied to solve the problem. By applying Charge Sharing, all data lines are shorted at the same time and quickly positioned as the average voltage to advance the compensated change time of the gate voltage in the next operation period. A buffer circuit and a current pass circuit were added to lower the Amplifier resistance connected to the line as a polar stabilization method. The advantage of suppressing the Ringing of the driving Thin Film Transistor can be obtained by increasing the stability. As a result, a circuit was designed to supply a stable current to the Organic Light Emitting Diode even if the characteristic deviation of the driving Thin Film Transistor occurs.

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Clinical Effects and Stability of the Maxillary Protraction Using the Lateral Cephalogram in Korean (상악골 전방견인 장치의 효과와 안정성에 대한 두부방사선 계측학적 연구)

  • Baik, Hyoung-Seon
    • The korean journal of orthodontics
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    • v.22 no.3 s.38
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    • pp.509-529
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    • 1992
  • Skeletal Class III malocclusion is one of the most difficult type to treat and stabilize. For a child with developing skeletal Class III malocclusion, the treatment objective would be to stimulate maxillary growth, particulary one who has markedly deficient maxilla, and to restrain excessive mandibular growth. In order to stimulate the maxillary growth, maxillary protraction appliance is the one of the effective orthopedic appliances in skeletal Class III. The purposes of this study were as follows ; evaluation of the skeletal and dental changes of the maxillary protraction in children with Class III Maxillary deficiency , comparison of the clinical effects between the group with RPE and labiolingual intraoral appliances , comparison of the clinical effects and stability related to the ages of the patients : stability of the maxillary protraction about 1 year after retention. The subjects consisted of 60 children between the ages of 8 and 13.4 who were diagnosed as Class III with maxillary deficiency and were treated with Face Mask (Delaire Type) from the Dept. of Orthodontics Yong Dong Severance Hospital, Yonsei University. 48 children wore the RPE and 12 children wore Labiolingual Appliance. Lateral Cephalograms were taken for each patient at before and after correction of anterior cross-bite in 60 children, and after an observation period of 10 to 14 months in 19 children. X and Y coordinate of 10 landmarks were analyzed using a horizontal line through sella and rotated $6^{\circ}$ down anteriorly as the horizontal reference axis, and a perpendicular verticual line through sella as the vertical reference axis. Each of the 31 measurents (10 verticals, 10 horizontals, 2 angles and 9 others) was statistically analyzed using SPSS/PC statistics. The results are as follows; 1. After maxillary protraction the maxilla and maxillary teeth moved downward and forward, while the mandible and mandibular incisor rotated downward and backward. 2. Maxillary protraction with rapid palatal expansion appliance was more effective than with labiolingual appliance. 3. More downward movement of the posterior palatal plane obserbed with maxillary protraction doing the midpalatal suture opening than with protraction after finishing the palatal expansion 4. The clinical effects of protraction and changes of the retention periods were not statistically significant among the age groups. 5. During the retention period, maxilla and maxillary teeth, and mandible and mandibular teeth moved downward and forward, however the mandibular changes were larger than the maxillary changes.

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Change of Antioxidant Activity and Quality Characteristics of Gaeseong-Juak Prepared with Prunus yedoensis Matsumura Extract during the Storage Period (화피 추출물 첨가 개성주악의 저장과정 중 항산화 활성 및 품질특성 변화)

  • Joo, Shin Youn
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.42 no.7
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    • pp.1086-1095
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    • 2013
  • This study investigated the quality characteristics, oxidative stability, and antioxidative activity of a Korean fried rice cake, Gaeseong-Juak (doughnut of waxy rice) to which Prunus yedoensis Matsumura (PYM) extract, vitamin C, and BHT were added and stored at $60^{\circ}C$ for 4 days. Gaeseong-Juak was prepared by adding PYM extract at 0, 0.5, 1, and 2% of waxy rice powder. It was found that as the content of PYM extract increased, L-values significantly decreased while a-value and b-value significantly increased (P<0.001). The hardness and adhesiveness were increased with an increase in PYM extract, and as the storage period increased. In the sensory evaluations, the sample containing 0.5% and 1.0% PYM extract gave good scores. In the Gaeseong-Juak with PYM extract, the acid value, peroxide value, and p-anisidin value of PYM extract groups were found to have a higher oxidative stability than those of 0% PYM extract group (P<0.05). The antioxidative activity of Gaeseong-Juak to which PYM extract was added increased as the content of PYM extract increased (P<0.001). It was suggested that the shelf life of Gaeseong-Juak could be extended by the use of natural antioxidants, reducing the deterioration of the quality of Gaeseong-Juak.

The Characterization of Anthocyanin Pigments Prepared from Cherry (Prunus serrulata L. var. spontanea Max. Wils.) for the Potential Sources of Red Colorant (적색 색소자원으로서의 버찌(Prunus serrulata L. var. spontanea Max. Wils.) anthocyanin 색소의 특성)

  • Kim, Yong-Hwan
    • Applied Biological Chemistry
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    • v.42 no.2
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    • pp.134-139
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    • 1999
  • The characteristics of anthocyanin pigments extracted from cherry(Prunus serrulata L. var. spontanea Max. Wils.) were investigated at the various conditions, such as light, temperature, organic acid, metal ion and pH. The pigments were fairly stable under the sunlight during the 20 days storage period at room temperature. The pigments covered with the Al-foil, as well as red, blue, green and yellow films, were very stable at pH 2.5. The high thermal stability (over the 64% at $115^{\circ}C$, 30 min) of the pigments in the dark at pH 2.5 was also found. In the presence of organic acid, the hyperchromic effect of red color was greatly increased in the dark at $25^{\circ}C$. Addition of metal ion, such as $Na^+,\;K^+,\;Mg^{2+},\;Ca^{2+}\;and\;Mn^{2+}$, was contributed on the stability in color at pH 2.5 throughout 20 days storage period in the dark at $25^{\circ}C$. However, $Cu^{2+}\;and\;Fe^{3+}$ caused the rapidly degradation of pigments, and $Al^{3+}$ converted red color to blueish violet. The hyperchromic effect of the red color increased, as pH decreased. Therefore, these results indicated that cherry anthocyanin pigments might be used as the potential sources of natural red colorant for foods.

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Effects of Temperature and Relative Humidity on Water Soluble Vitamin Contents in Commercial Vitamin Tablet (저장 온도 및 상대습도가 비타민 정제 중 수용성 비타민 함량의 변화에 미치는 영향)

  • Lee, Jae-Hwang;Kim, Sae-Gon;Lee, Dong-Un;Park, Seok-Jun;Lee, Jin-Hee;Lee, Kang-Pyo;Kim, Dong-Seob;Choi, Sung-Won;Baik, Moo-Yeol
    • Korean Journal of Food Science and Technology
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    • v.37 no.6
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    • pp.1028-1034
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    • 2005
  • Effects of temperature and relative humidity on contents of water-soluble vitamins (vitamins $B_1,\;B_2,\;B_3,\;B_6$, and C) of two commercial tablets ("Multivitamin Dandelion" and "Chewable vitamin C") were investigated. When stored at various temperatures (25, 35, and $45^{\circ}C$) with cap, all measured vitamins were stable and degraded very slowly during 24 weeks of storage; low relative humidity (11% RH) without cap also provided stability during storage period. At higher relative humidities (75 and 100% RH), contents of all water-soluble vitamins, except vitamins $B_2\;and\;B_3$, decreased significantly at early storage period. These results showed that stability of water-soluble vitamins is highly dependent on relative humidity rather than storage temperature.

Magnetic Parameters as Indicators of Late-Quaternary Environments on Fort Riley Kansas (암석 자기 변수들을 이용한 제4기 고환경 복원-Fort Riley 캔사스)

  • Park, kyeong
    • The Korean Journal of Quaternary Research
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    • v.11 no.1
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    • pp.57-68
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    • 1997
  • Climatic change of the late-Quaternary period has been record-ed in the loess deposits of the central Great plains and the record of such change is extractable using a number of approaches and parameters. The stratigraphy of loess deposits which have been investigated on Fort Riley exhibits the same sequence of loess units and intercalated buried soils as is found elsewhere in the re-gion but adds detail unique to the reservation Upland late-Qua-ternary composite stratigraphy preserved on the reservation con-sists of the basal Sangamon soil of the Last interglacial(c. 120-110ka), Gilman Canyon Formation(c. >40 -20ka), Peoria loess(c. 20 -10ka) Brady soil(c. 11 -10ka) Bignell loess(c. 9-\ulcornerka). and mod-ern surface soil. Application of magnetic analyses has provided proxy data sets that represent a time series of climatically regulated pedogenesis/weathering and botanical composition. magetic data have yielded an impression of the variation in climate from Sangamon time to the late Holocene through a reconstruction of the history of pedogenesis/weathering. Sangamon soil formation dominated the reservation durin the Last interglacial as indicated by magnetic parameters. During Gil-man Canyon time loess influx was usually sufficiently slow as to permit pedogenesis which appears to have been at a maximum twice during that time. Warm season grasses were important dur-ing soil formation but diminished in importance during the peri-ods of more rapid loess fall which were cooler and perhaps wet-ter. Peoria loess fall a function of the deterioration of climate during the last Glacial Maximum thinly blanketed the reservation with thickest accumulations occurring to the north-west(Bala Cemetery site)proximal to the source region. Long-term surface stability did not apparently occur within Peoria time but short-term stability may be indicaed by the presence of thin weathering zones(incipient soils) in the Peoria loess. Re-gional landscape stability prevailed during the environmental shift at the Pleistocene/Holocene transition resulting in forma-tion of the well expressed Brady soil. One or more weak soils developed in the Bignell loess as it ac-cumulated. A notable feature of the Bignell loess is the appear-ance of the Altithermal dry period: the loess experienced little weathering and was dominated by warm season grasses until the latter of the Holocene.

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Comparison of Drying Yield, Meat Quality, Oxidation Stability and Sensory Properties of Bone-in Shell Loin Cut by Different Dry-aging Conditions

  • Cho, Soohyun;Kang, Sun-Moon;Kim, Yun-Seok;Kim, Young-Chun;Ba, Hoa Van;Seo, Hyun-Woo;Lee, Eun-Mi;Seong, Pil-Nam;Kim, Jin-Hyoung
    • Food Science of Animal Resources
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    • v.38 no.6
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    • pp.1131-1143
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    • 2018
  • This study aimed to investigate the drying yield, meat quality, oxidation stability and sensory properties of Hanwoo beef loin subjected to different dry-aging conditions. A total of 54 Hanwoo beef loins (bone-in, $6^{th}-13^{th}$ ribs) with fat cover at 2 d postmortem were assigned to four groups and hung in a dry-aging room at a controlled temperature ($2^{\circ}C-4^{\circ}C$), humidity (65%-85%) and air velocity (3 m/s). Four treatment conditions were tested; the respective temperature, humidity and treatment duration are as follows: T1, $2^{\circ}C$, 85%, 60 d; T2, $2^{\circ}C$, 65%, $20d+2^{\circ}C$, 75%, $20d+4^{\circ}C$, 85%, 20 d; T3, $2^{\circ}C$, 75%, $20d+4^{\circ}C$, 85%, 40 d; T4, $4^{\circ}C$, 85%, 60 d. The drying yield, total aerobic counts and fat contents increased, whereas the moisture content, meat color (CIE $L^*$, $a^*$, and $b^*$), and Warner-Bratzler shear force values decreased significantly during the aging period for all treatments (p<0.05). The cooking loss (%) did not change significantly until 40 d, and it was significantly higher in T1 and T4 than in T2 and T3 at 60 d (p<0.05). The water-holding capacity, pH and lipid oxidation [thiobarbituric acid reactive substance (TBARS) values] increased during aging (p<0.05). The sensory scores for tenderness, juiciness, flavor, and overall acceptability of dry-aged loin muscles increased as the aging period increased. T2 and T3 had significantly higher sensory scores and T1 had significantly lower scores for tenderness, juiciness, flavor, and overall acceptability at 20, 40, and 60 d for loin muscles (p<0.05).

THE CORRECTION OF CLASS III MANDIBULAR ASYMMETRY USING BILATERAL SAGITTAL SPLIT RAMUS OSTEOTOMY AND LATERAL ANGLE REDUCTION (외측 하악각 골절제술을 동반한 시상분할골절단술을 통한 골격성 3급 하악골 비대칭 환자의 치료)

  • Kang, Hee-Jea;Song, In-Woo;Kang, Yung-Ki;Kim, Jong-Ryoul
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.32 no.2
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    • pp.132-140
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    • 2010
  • Purpose: The aim of this study is to identify the usefulness of unilateral mandibular angle ostectomy, so-called "Lateral Angle Reduction", in asymmetric prognathism patients by the assessment of postoperative stability and esthetic results Patients and methods: For the retrospective study, 10 skeletal class III mandibular asymmetry patients who were performed SSRO and unilateral mandibular angle ostectomy, Lateral Angle Reduction, was selected. Lateral and posterioanterior cephalogram was taken before surgery (T0), 1day after surgery (T1) and 6month after surgery (T2). To know the esthetic results the facial width and lateral facial contour were examined on posterioanterior cephalogram and to know the postoperative stability B point and Incisor inferius was examined on lateral cephalogram. Statistical analysis was performed. Results: From T0 to T1, Intergonial width was significantly decreased, dominantly at shortened side but no significant changes at lengthened side. Those were well-maintained during 6 months. Lateral facial angle and Ramus angle was significantly decreased on only shortened side from T0 to T1. As a result, after surgery, there were no significant differences in all measurements between shortened side and lengthened side. Ramus deviation angle in shortened side and ramus angle in lengthened side which reflect the angulation of ramus on frontal plane didn't show significant changes after surgery and during postsurgical periods. Lower dental midline showed no statistical changes during postsurgical period. The relapse rate on B-point was 11.92%. Conclusion: Unilateral "Lateral angle reduction" in the asymmetric mandible is valuable to obtain the narrow lower face and symmetric facial contour with a good stability.