• Title/Summary/Keyword: Mass changes

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Impact Behaviors of Stitched Sandwich Composites Under Low Energy Impact Using Drop Weight Impact Tester (고낙하추 충격시험기를 이용한 스티칭된 샌드위치 복합재의 저에너지 충격거동 연구)

  • 윤성호;이상진;조세현
    • Composites Research
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    • v.12 no.5
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    • pp.54-64
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    • 1999
  • This study investigated the impact behaviors of the stitched sandwich composites under the low energy impact by the use of drop weight impact tester. These sandwich composites condidted of the glass fabric faces with a urethane foam core. The upper face and the lower face were stitched to combinr through the core thickness direction using the polyester reinforcements. Four types of the stitched sandwich composites, each having a different core thickness, were tested to determine the effects of the core thickness. The impact conditions were changes with the variations of the mass and drop height of the impact tup. The test results showed that the core thickness and the impact condidtions such as the drop height and the mass of the impact tup affected the impact force, the contact time, and the strain behaviors of the stitched sandwich composites. The stitched sandwich composites are able to avert the damage and also maintain the structural integrity even thouth the presence of the damage owing to the through-the-thickness reinforcements. However, it is important to improve the wetting ability of the stitched reinforcements so that the conventional structures are substituted for the stitched sandwich composites effectively.

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A Study on Durability Variation of Concrete due to Water Content Changes (콘크리트 내 수량증감에 의한 내구 품질 변동에 관한 연구)

  • Woo, Young-Je;Ryu, Hwa-Sung;Jung, Sang-Hwa;Kwon, Ki-Jun
    • Journal of the Korean Society of Hazard Mitigation
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    • v.7 no.2 s.25
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    • pp.1-6
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    • 2007
  • When the water content within concrete swells, diverse problems occur such as drop in durability. Due to this reason, a change is being managed in the unit water contents by using electric capacity measurements, high frequency heating methods, and unit-volume mass measurements, which are methods of measuring the unit water contents. Particularly, Japan is prescribing the guideline of management on a change in unit water content unit quantity $({\pm}10,\;15,\;20kg//m^3,\;etc.)$. However, the guideline of Japan dose not consider a fall in durability, and is decided on the value of pass-fail criteria by random fabrication errors and measurement errors. Consequently, this study was aimed to investigate the influence of a change In water content within concrete due to an addend caused by management error and to an artificial addend, upon drop in durability.

Sensitivity Analysis of Vortical Hull Girder Vibration (선체 저차 상하고유진동 감도해석)

  • Dae-Seung Cho;Sa-Soo Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.35 no.3
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    • pp.54-61
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    • 1998
  • This paper presents a prediction method of natural frequencies of vertical hull girder vibration based on design sensitivity analysis in case of design modification and the variation of loading condition. The resented method premises the vibration analysis by the transfer matrix method. Governing sensitivity equation is derived from the direct differentiation of state vector and transfer matrix to parameters and its transfer over all the hull girder elements. Derivatives of natural frequencies and mode shapes are determined by two trial calculation of the governing equation. Using the derivatives, the changes of natural frequencies and mode shapes can be predicted when mass and stiffness parameter's are changed. As results, it is possible to optimize ship structure as well as to avoid troublesome calculation in hull girder vibration analysis rationally and efficiently. To verify the accuracy and efficiency of the resented method numerical results obtained by both the sensitivity analysis and the ordinary reanalysis far a real ore/bulk carrier in case of the change of mass and stiffness parameters are compared.

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Ischemic Infarcion Model by Middle Cerebral Artery Occlusion using Allogenic Blood Clot in Beagle Dogs (비글견에서 동종혈전 색전술을 이용한 중간대뇌동맥의 허혈성 뇌경색 모델)

  • Kim, Younghwan;Choi, Sooyoung;Lee, Kija;Han, Woosok;Choi, Hojung;Lee, Youngwon
    • Journal of Veterinary Clinics
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    • v.33 no.1
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    • pp.10-15
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    • 2016
  • The purpose of this study was to establish reproducible ischemic infarction model using allogenic blood clot in beagle dogs and identify induced ischemic lesion after middle cerebral artery occlusion using magnetic resonance imaging (MRI) and histopathologic findings. Twenty eight male beagle dogs with no evidence of neurologic disease were experimented. Allogenic embolus was made using a healthy beagle dog. After internal carotid artery (ICA) was exposure, 16G catheter was introduced through the ICA. The dog was administered 0.3 ml blood clot for 15 seconds followed by 3 ml of saline for 15 seconds. MRI scans were performed with 1.5T to evaluate ischemic lesion at 7 days after middle cerebral artery occlusion procedure. Evaluation parameters of MRI include location, distribution, infarction type, margin, shape, mass effect and intensity of T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), fluid attenuated inversion recovery (FLAIR) sequence, diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC). On MRI, all dogs (28/28) showed focal or multifocal lesion including telencephalon and thalamus lesions, especially caudate nucleus (24/28). These lesions had well-defined margin from adjacent brain parenchyma, none or mild mass effect and various shape. Most of dogs appeared hyperintensity on T1WI, T2WI, FLAIR, and DWI/ADC, corresponding to chronic infarction. These lesions were histopathologically confirmed atrophic changes and unstained lesion. In conclusion, MRI is the useful method to provide information about ischemic infarction in dogs and the best reproducible ischemic infarction model was developed by using allogenic blood clot.

Analysis of polyphenolic metabolites from Artemisia gmelinii Weber ex Stechm. and regional comparison in Korea

  • Park, Mi Hyeon;Kim, Doo-Young;Jang, Hyun-Jae;Jo, Yang Hee;Jeong, Jin Tae;Lee, Dae Young;Baek, Nam-In;Ryu, Hyung Won;Oh, Sei-Ryang
    • Journal of Applied Biological Chemistry
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    • v.62 no.4
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    • pp.433-439
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    • 2019
  • Artemisia species are widely used as food ingredients and raw material in traditional medicine. However, to date, the secondary metabolites of Artemisia gmelinii Weber ex Stechm. have not been sufficiently investigated. The secondary metabolites of A. gmelinii, which was collected from representative regions in Chungbuk, Gangwon, and Gyeongbuk, were analyzed using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTof MS) combined with an unsupervised principal component analysis (PCA) multivariate analysis. In the loading scatter plot of PCA, significant changes in metabolites were observed between the regions, ten metabolites (3: 5-O-caffeoylquinic acid, 4: 4-O-caffeoylquinic acid, 8: trans-melilotoside, 12: quercetin 3-O-hexoside, 15: 3,4-O-dicaffeoylquinic acid, 17: 3,5-O-dicaffeoylquinic acid, 18: 4,5-O-dicaffeoylquinic acid, 19: syringaldehyde, 20: caffeoylquinic acid derivative, and 23: icariside II) were evaluated as key markers among twenty-five identified metabolites. Interestingly, the contents of the identified marker significantly differed between the three groups. This is the first study to report the presence of marker metabolites and their correlating geographical cultivation in A. gmelinii.

A Study on the X-ray Diffraction of Rabbit Glycerin Muscle by Spin Labeled on SH (SH에 Spin Label한 Rabbit Glycerin처리근육의 X선 회절에 관한 연구)

  • 김덕술;송주영
    • Journal of Life Science
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    • v.8 no.6
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    • pp.681-686
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    • 1998
  • IASL(iodo acetamide) and MSL(maleimide) disordered the orderly helix arrangement of myosin in the rest state of spin level. Especially the effect of IASL was great. Equatorial reflection(10,11) change inferred that myosin head was moved to the vicinity of actin filament by spin level. The intensity change of 143 $\AA$ and 72 $\AA$ could offer infor-mation of the mass projection of population of myosin heads along the filament axis. The slope of intensity profile of the mass projection of 143 $\AA$ and reflection of IASL is appeared and that of MSL is appeared sharply. The dec-rease of 215 $\AA$ reflection intensity the periodical characteristic of 143 $\AA$ reflection by spin label. The raise of MSL actin reflection at 51 $\AA$ and 59 $\AA$ in the actin reflection change refers that the shifted myosin head binds a certain actin or changes an actin structure by spin label effect. Because iodo acetamide has a tendency to decease the actin reflection, actin dose not bind myosin head. From this result, we could conclude that LASL and MSL are spin labeled on SH of myosin head and disordered the helix arrangement of actin.

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A Case of Bronchiolar Papilloma (세기관지 유두종 1예)

  • Lee, Sang Hak;Kim, Chi Hong;Moon, Hwa Sik;Song, Jeong Sup;Park, Sung Hak;Jang, Eun Deok
    • Tuberculosis and Respiratory Diseases
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    • v.43 no.5
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    • pp.792-797
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    • 1996
  • A 59-year-old woman was admintted to the hospital because of intermittent fever and right side chest pain. She has a same episode eight months before this entry. Chest CT scan demonstrated ill-defined parenchymal consolidation containing dilated bronchi of right lower lung field, but no endobronchial mass in the bronchial trees. Fiberoptic bronchoscopy seeking the cause of recurrent pneumonia revealed a small, round mass nearly completely obstructing me lumen of basal segmental bronchus of right lower lobe. The diagnosis of bronchiolar papilloma was made from the biopsy specimens of the bronchoscopic examination. The patient was treated with right lower lobectomy because of irreversible secondary changes below the obstructed bronchus. This thoracotomic excision resulted in complete relief of symptoms and the postoperative course was uneventful for 12 months. Here we report a extremely rare umor with a brief review of literatures.

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Selection of Capillary Tubes for HCFC-22 Alternative Fluids (HCFC-22 대체냉매의 모세관 선정)

  • Jung, D.S.;Kim, C.B.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.3
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    • pp.435-449
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    • 1995
  • In this paper, pressure drop through a capillary tube is modeled to determine the length of a capillary tube for a given set of conditions. HCFC-22 and its alternatives, HFC-134a, R407B, and R410A are used as working fluids. The conditions on which the model is tested are as follows : condensing temperature; 40.0, 45.0, 50.0, $55.0^{\circ}C$, degree of subcooling;0.0, 2.5, $5.0^{\circ}C$, capillary tube exit condition;choked flow, capillary tube diameter;1.2~2.4mm, mass flow rate;5.0~50.0g/sec. The results justify the use of Stoecker's model which yields the results very close to the values in ASHRAE handbook. While McAdams' method yields much better results than Duckler's in calculating the viscosity of the fluid in 2-phase, the friction factor suggested by Stoecker seems to be the best for capillary tubes of large diameter used in residential air conditioners. For each refrigerant, 372 data with various variables are calculated by the model. The results show that capillary tube length varies very uniformly with changes in condensing temperature and degree of subcooling. Based on this fact, regression analysis is performed to determine the dependence of mass flow rate on the length and diameter of a capillary tube, condensing temperature, and degree of subcooling. Thus determined correlation yields a mean deviation of 2.36% for 1,488 data, showing an excellent agreement.

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The effects of Very Low Calorie Diet using meal replacements that contain Herbal extracts on weight reduction and health promotion (한약추출물을 함유한 식사대용식이가 체중감량과 초저열량식이의 부작용에 미치는 영향)

  • Choi, Seung;Kim, Ji-Young;Jang, Yu-Gyung;Kim, Sang-Yeon;Park, Mi-Hyun;Hong, Seong-Gil;Hwang, Seong-Ju;Choi, Hyung-Suk
    • Journal of Korean Medicine for Obesity Research
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    • v.4 no.1
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    • pp.81-94
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    • 2004
  • Background: The VLCD that supplies only 400-800kcal meal per day has a lot of problems and can severely harm the health. Certain herbs are known to the side-effects such as weakness, skin dehydration, and dizziness. If VLCD with meal-replacement containing these hearbs can effectively minimize the side-effects, it make weight management easier and reduce any possible danger the health. Objectives: This prospective, double-blinded study is intended to compare the severity of symptoms induced by VLCD and weight loss between the case group supplied with meal-replacement herbal extracts(n=29) and controlled group supplied with meal-replacement not containing herbal extracts(n=29). This was with 52 volunteers for 4 weeks. The measurements of this experiment were as follows: symptoms caused by patients' subjective judgments, the result of blood test illustratingerol level, total protein etc., and changes in overall weight, fat mass and lean body mass. Result: we concluded that there are no significant differences in weight change between case group and controlled group, and that the total protein at the end of trial was significantly higher in case group than in controlled group, and triglyceride level at the end of trial was lower in case group than in controlled group. As expected, the side-effects such as hair loss and dehydration in skin are also lessin case group than in controlled group.

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The Effects of Taeeumjowi-tang Extract Granule on Metabolic Syndrome Risk Factors with Obesity: A Single Group, Prospective, Multi-Center Trial (태음조위탕 엑스과립이 비만을 포함한 대사증후군 위험인자에 미치는 영향에 대한 연구: 단일군, 전향적, 다기관 임상연구)

  • Kwak, Jin-Young;Ahn, Taek-Won
    • Journal of Sasang Constitutional Medicine
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    • v.32 no.2
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    • pp.48-60
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    • 2020
  • Objective The purpose of this study is to study the effects of Taeeumjowi-tang extract granule on metabolic syndrome with obesity in Taeeumin. Methods We studied 206 subjects who diagnosed metabolic syndrome with obesity and classified Taeeumin by a Sasang constitution analysis tool. The subjects were administered by Taeeumjowi-tang for 12 weeks. We investigated the changes of body mass index, abdominal circumference, the number of risk factors for metabolic syndrome, lipid, fasting blood sugar, Hemoglobin A1c, free fatty acid, insulin, and blood pressure. Results Body mass index and abdominal circumference, systolic and diastolic blood pressure were significantly reduced after 4 weeks, 8 weeks, and 12 weeks of administration compared to before administration. Triglyceride significantly decreased after 8 weeks and 12 weeks of dosing compared to before taking. Low density lipoprotein cholesterol, fasting blood sugar were significantly increased after 8 weeks of administration compared to before administration. High density lipoprotein cholessterol was decreased significantly after 4 weeks of administration compared to before administration. The number of risk factors for metabolic syndrome, Hemoglobin A1c increased significantly after 12 weeks of administration compared to screening. Conclusions In this study we knew that Taeeumjowi-tang extract granule is very efficient in metabolic syndrome, especially in obesity and hypertension, triglyceride, insulin resistance.