• 제목/요약/키워드: homogenous

검색결과 492건 처리시간 0.027초

Bending analysis of softcore and hardcore functionally graded sandwich beams

  • Hadji, Lazreg;Safa, Abdelkader
    • Earthquakes and Structures
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    • 제18권4호
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    • pp.481-492
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    • 2020
  • A New hyperbolic shear deformation theory is developed for the bending analysis of softcore and hardcore functionally graded sandwich beams. This theory satisfies the equilibrium conditions at the top and bottom faces of the sandwich beam and does not require the shear correction factor. The governing equations are derived from the principle of virtual work. Sandwich beams have functionally graded skins and two types of homogenous core (softcore and hardcore). The material properties of functionally graded skins are graded through the thickness according to the power-law distribution. The Navier solution is used to obtain the closed form solutions for simply supported FGM sandwich beams. The accuracy and effectiveness of proposed theory are verified by comparison with previous research. A detailed numerical study is carried out to examine the influence of the deflections, stresses, and sandwich beam type on the bending responses of functionally graded sandwich beams.

국내에서 발생한 면양의 만성 동중독증 예의 관찰 (Chronic Ovine Copper Toxicosis in Korea)

  • 김대용;권오경;서일복
    • 한국임상수의학회지
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    • 제15권2호
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    • pp.455-459
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    • 1998
  • Ten sheeps from one farm had sudden onset of anorexia, jaundice and hemoglobinuria and died within 3 days after showing clinical signs during 3 months period. Postmortom examination was performed on one case and copper concentrations in the livers kidney and serum of the necmpsied minim were analysed. Grossly, the conjunctive, subcutaneous tissue and abdominal fat were generally icteric. The liver was enlarged with yellowish orange in color. The kidney was enlarged with dark red in color and the urinary bladder was filled with dark red urine. Histopathologically, centrilobular hepatocellular necrosis, neutrophilic infiltrations bile stasis and aggregation of fine granules-laden macrophages in the portal area were noted in the liver. Most of the Bowman's spaces and renal tubules were filled with homogenous eosinophilic fluid. Extramedullary hematopoiesis was noted in the submandibular lymph node. Copper concentrations in serum, liver and kidney of the necropsied animal were 25.0, 2732.8 and 471.3 ppm respectively. Based on the gross and histopathological findings and the high copper concentrations in the organs, this case was diagnosed as chronic copper toxicosis. Possible etiology on this outbreak is also discussed.

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Thixoforging Process에 의하여 제조한 금속복합재료 실린더라이너 부품의 기계적 특성 평가 (Mechanical Characteristics Evaluation of Metal Matrix Composites Cylinder Linear Fabricated by Thixoforging Process)

  • 허재찬;이승후;강충길
    • 한국정밀공학회지
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    • 제20권2호
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    • pp.58-65
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    • 2003
  • The conventional forming process such as squeeze casting or die casting for fabricating metal matrix composites products have a disadvantage such as non homogenous distribution of reinforcement, weak bonding between matrix and reinforcement and cost increase in parts fabrication. Thixoforming process has been accepted as a new method for fabricating the net shaped metal matrix composites with lightweight and wear resistance. In this paper, the effect of volume fraction and reinforcement sizes on mechanical properties in cylinder liner part of metal matrix composites has been investigated with processes parameters such as pressure and velocity. Moreover, the methods to obtain the thixoforged composites cylinder liner with high quality has been proposed. To evaluate the composites cylinder linear fabricated at the conditions proposed in this study, mechanical properties of fabricated composites cylinder linear were compared with those of commercial composites cylinder linear.

흉벽에 발생한 거대한 유건종 1례 (A Large Dumb Bell Shaped Desmoid Tumor in Chest Wall: A Case Report)

  • 박주철;유세영
    • Journal of Chest Surgery
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    • 제11권4호
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    • pp.456-460
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    • 1978
  • Desmoid tumor is found most often in the anterior abdominal wall of parous women. Although it may originate in virtually any musculotendinous structure, those of the chest wall are rare. We experienced a case of large dumb bell shaped desmoid tumor originated in intercostal muscle and invaded anterior chest wall, pericardium, pleura and the lung. The patient was healthy in appearance except a painful swelling on the anterior chest wall. Roentgenographic studies demonstrated a huge homogenous mass in the right anterior chest cavity. He was treated with resection of the tumor including .anterior chest wall, a portion of the pericardium, middle lobe, and part of upper & lower lobes of the right lung because of tumor invasion. The tumor composed with two parts, one [$5{\times}4{\times}3$cm in size] is over the rib cage and another [$10{\times}15{\times}10$cm in size] is in the right chest cavity. Postoperative course was uneventful and there was no evidence of recurrence until last visit, 5 months after surgery.

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Correlation between Dietary Sodium and Electroecardiographic Left Ventricular Hypertrophy Among Hypertensives

  • Jones, Daniel W.
    • Journal of Preventive Medicine and Public Health
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    • 제27권2호
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    • pp.226-229
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    • 1994
  • In hypertensives, electrocardiographic left ventricular hypertrophy (LVH) is an independent risk factor for cardiovascular disease. Animal and human studies suggest an association between left ventricular mass and dietary sodium (Na) intake. This study determined if dietary Na intake in a homogenous ethnic population is associated with electrocardiographic LVH (S in Vl + R in $V5{\geq}5.5 mV$). Blood pressure (BP), body mass index, EKG, and 24 hour urine Na and potassium (K) excretion were determined in 40 otherwise healthy Korean patients with untreated essential hypertension on the standard Korean diet. Among these variables, only Na excretion (mmol/day) was significantly different between those with and without LVH $[LVH+:357{\pm}50,\;LVH-;\;268{\pm}25(p=0.04]$. Thus, dietary sodium intake may be predictive of electrocardiographic LVH.

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고분자/$MoS_2$ 복합재료의 마찰 및 마모특성 (Characteristics of Friction and Wear of Polymer/MoS$_2$ Composites)

  • 문탁진;윤호규
    • Tribology and Lubricants
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    • 제5권1호
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    • pp.12-20
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    • 1989
  • The friction and wear behavior of molybdenum disulfide filled polymer composites sliding against metal has been investigated using pin-on-disc machine and microscope. The observed wear rates were reduced by the addition of MoS$_2$ to nylon and this can be attributed to the homogenous transfer of MoS$_2$ to the counteddace thereby modifying sliding conditions. The friction of filled and unfilled nylon was increased with increasing sliding speed, and the catastropic wear rate was occurred at high normal load. This have been explained by thermal degradation. In the case of HDPE, however, the wear rate was not always reduced by the addition of MoS$_2$ and the influence of MoS$_2$ was mainly even the opposite. Filled and unfilled HDPE had lower values of friction and wear rate than those of nylon. Micrographs appeared that the delamination of the worn surface in nylon/MoS$_2$ composite occurred and revealed that the worn surface of HDPE presented a number of characteristic features as wear grooves, pulls, and smears and crescents.

텐션 레벨링 공정 최적화를 위한 수식 모델 - Part I : 곡률 및 압하력 예측 (A new Model to Optimize the Process Conditions in Tension Leveling - Part I : Prediction of the Strip Curvature and the Roll Force)

  • 조용석;황상무
    • 소성∙가공
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    • 제22권7호
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    • pp.371-376
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    • 2013
  • The shape defects such as edge waves and center buckles may be formed in the rolled strip because rolling can easily produce non-homogenous elongation across the strip width. The main purpose of tension leveling is to remove such defects by eliminating the differences in elongation. In this paper, a new approach for the optimization of the process conditions in tension leveling is presented. The approach consists of an analytic model for the prediction of the strip curvature and the force at each roll. The accuracy of the proposed model is examined through comparison with the predictions from a finite element model.

Intralobar Pulmonary Sequestration: 수술 1예 보고 (Intralobar Pulmonary Sequestration: A Case Report)

  • 양기민;안긍환;김용일
    • Journal of Chest Surgery
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    • 제4권1호
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    • pp.55-58
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    • 1971
  • Intralobar pulmonary sequestration is rare congenital lung disease, in which systemic artery supplies a congenitally cystic portion of the lung. Patient was 19 years old male whose complaints were fever, chest pain and sputum. Chest film showed a round homogenous density and air-fluid level at the left lower lung field and on bronchogram, contrast materials did not enter the abscess pocket. By operation multiple lung abscess pockets at the lower lobe were noted. An aberrant artery, measuring 0.4cm. in diameter and 2 cm. in length, arised from the aorta just above the diaphragm and entered the pusterior basal segment of left lower lobe. After division of the artery, left lower lobectomy was done ana postoperative hospital course was uneventful. Pathologic findings were multiple lung cysts which were not connected to the left lower lobe bronchi and an aberrant artery which showed elastic lamillation and mild sclerotic change.

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전통적 벨칸토 발성훈련법에 기초한 음성전문직업인 발성훈련의 표준화 (Standardization Voice Training Method for Professional Voice User Based on Traditional )

  • 김철준
    • 대한후두음성언어의학회지
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    • 제28권1호
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    • pp.17-19
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    • 2017
  • Opera singers train their vocal organ to have a good timbre of voice. They train and train again to have a strong resonance, large range of voice, homogenous color of voice, a voice goes far and to avoid vocal disorder, etc. This article is analyzing from scientific and medical perspective. It could approach the secret of the great art of 400 years history - . Furthermore standardizing voice training method based on will facilitate to train, therapy and care the voice professional user and voice disorders.

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인천항 지역의 지반정수 신뢰성 분석 (Reliability Analysis of Geotechnical Properties in Incheon Port Area)

  • 신은철;전재구;김형준;이충호
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2009년도 춘계 학술발표회
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    • pp.952-960
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    • 2009
  • Foundation soils are greatly influenced on the stability of structures. The soft clay deposited in Incheon Port area is named either nomally consolidated clay or unconsolidated clay. New harbor structures will be constructed in Incheon Port area. Not sufficient soil boring datum are obtained from the filed soil exploration due to limited time and cost. The harbor construct site is pretty large area and the soils are not homogenous. This paper presented the result of reliability analysis which was performed by both Bayesian approach and analysis of variance.

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