• Title/Summary/Keyword: 수축대

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A Structural Behaviour Analysis System for Simulating the Construction Steps of Prestressed Concrete Bridges (시공단계를 고려할 수 있는 프리스트레스트 콘크리트 교량 전용 거동해석 시스템)

  • 안경한;김대영;이환우;김덕경;김우종;김철영
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1991.10a
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    • pp.96-101
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    • 1991
  • 프리스트레스트 콘크리트 교량은 콘크리트와 PS 강재의 역학적 장점들을 십분 활용하여 경제적인 단면 구성이 가능한 반면, 서로 다른 두 재료의 복합적인 특성들 즉, 콘크리트의 크리이프 (creep), 건조수축 (shrinkage)과 PS 강재의 이완 (relaxation) 등과 같이 시간에 따라 변화하는 인자들로 인하여 복잡한 구조적 거동을 보여 해석상 어려움이 따른다. 이와같은 복합거동은 시공순서와 시공방법에 의해 시공중의 구조계와 지지조건 등이 변화하는 경우에는 더욱 복잡한 양상을 띄게 된다. 뿐만 아니라 박스 거더와 같은 박벽요소에서는 일반적인 보요소(beam element)로는 나타낼 수 없는 ?(warping)을 무시할 수 없으므로 ? 자유도를 구현할 수 있는 특수한 기능의 구조해석용 프로그램의 개발이 절실히 요망된다. 그리고 시공단계별로 출력되는 많은 양의 수치결과들을 설계와 시공실무자에 지향된 형태로 조합, 변형시켜 그래픽 화면상에 나타내는 후처리 프로그램(Post-processor) 기능도 구조해석용 프로그램의 개발 못지않게 중요하다. 본 연구의 목적은 삼성종합건설과 서울대 토목공학과가 공동으로 ?(warping) 자유도를 포함한 7개의 자유도를 갖는 3차원 보요소를 사용하여 PS 콘크리트의 재료적 특성인 크리이프와 건조수축, 그리고 강재의 이완(relaxation)을 포함한 프리스트레싱력의 손실을 고려할 수 있고 시공 단계별 구조계의 변화 및 지지조건들의 다양한 변화를 효율적으로 모사할 수 있는 프로그램의 개발에 있다.

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Congenital Constriction Band Syndrome of Hand ; The Correction Under The Microscope (선천성 수부 윤상 수축대 증후군에 대한 미세현미경을 이용한 수술적 교정)

  • Hwang, Ho;Kim, Yong-Kyu;Whang, Jong-Ick
    • Archives of Reconstructive Microsurgery
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    • v.14 no.1
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    • pp.70-76
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    • 2005
  • The Z-plasty has been known as a most common surgical treatment of congenital circumferential constriction band syndrome of the hand. There were thirteen patients of congenital circumferential constriction band syndrome of the hand. All patients underwent Z-plasty under microscope. we did microsurgical dissection to minimize vascular, neural and lymphatic injury, and then considering secondary correction and scar contracture, tried to preserve as much subcutaneous fat and skin flap as possible without any excision. There were less skin necrosis and lymphedema as a result of vascular compromise. Using microscope offers several advantages. First, preventing vascular, neural and lymphatic injury. Second, getting an accurate suture approximation. finally, preserving as much subcutaneous fat and skin flap as possible without any excision. The outcome of digit growth and contour can be excellent than we expected. As a results, we believe that correction of congenital circumferential constriction band syndrome of the hand under the microscope have better results.

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Losartan Modifies Nitric Oxide-related Vasorelaxation in Isolated Aorta of Spontaneously Hypertensive Rat (선천성 고혈압흰쥐 적출대동맥에서 Nitric Oxide와 관련된 이완 반응에 Losartan이 미치는 영향)

  • Park, Bong-Gee;Han, Hyung-Soo;Kim, Choong-Young
    • The Korean Journal of Pharmacology
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    • v.30 no.3
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    • pp.337-342
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    • 1994
  • It is well known that angiotensin converting enzyme inhibitors(ACEIs) increase endothelium-dependent relaxation in aortic strips of spontaneously hypertensive rats(SHR) and this increase in relaxation may be due to altered endothelial nitric oxide breakdown. But there are few studies on the effect of the angiotensin II receptor blocker on the nitric oxide-mediated relaxation. So we attempted to investigate the effect of angiotensin II receptor blocker on the nitric oxide-dependent relaxation in isolated aorta of SHR. Two week-treatment of losartan (30 mg/kg/day) increased the acetylcholine$(10^{-9}\;to\;10^{-5}\;M)$-and histamine$(10^{-8}\;to\;10^{-4}\;M)$-induced relaxation in endothelium intact strips but 90 minutes-treatment of losartan $(10^{-4}\;M)$ showed no increase in relaxation. The phenylephrine $(10^{-7}\;M)$-induced contraction, repeated every 2 hours, was diminished gradually following lipopolysaccharide (LPS)-treatment $(100\;{\mu}g/ml)$ but there was no significant difference in enalapril- and losartan-treated group compared with control group. These results suggest that activity of the endothelial constitutive NO synthase may be changed by chronic treatment of angiotensin II receptor blockers and ACEIs but angiotensin II antagonist and ACEI have no effect on the inducible NO synthase activity in the isolated aorta of SHR

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Change on Lens Accommodation and Pupil Light Reflex in VDT works (VDT작업이 안 조절반응과 동공 대광반사에 미치는 영향)

  • Kim, Eun-A;Kim, Yang-Ho;Jin, Young-Woo;Chai, Chang-Ho;Choi, Yong-Hyu;Moon, Young-Hahan
    • Journal of Preventive Medicine and Public Health
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    • v.30 no.3 s.58
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    • pp.599-608
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    • 1997
  • We studied on change of lens accommodation and pupil light reflex caused by VDT work in six women and compared them with those of other office works. The results were as follows. 1. In VDT work the accommodation contraction velocity decreased during the first 2-hr VDT task, then recovered markedly by the end of the one-hour lunch break, and decreased again by the end of the 2nd 2-hr VDT task. Changes of relaxation velocity showed similar pattern although it was less typical than that of contraction velocity 2. There was no marked change in accommodation contraction velocity and amplitude of accommodation in general office work and near-distance office work, and in the near-distance office work accommodation relaxation velocity decreased according to work load without recovery after lunch break. 3. Initial pupil diameter, initial pupil area of light reflex decreased significantly during VDT task only in VDT work and didn't recover after lunch break. These results suggest possibility that changes of accommodation contraction velocity, accommodation relaxation velocity, near point distance, and pupil diameter and area are useful in evaluating characteristics of VDT work. For this, more research adjusted individual differences, circadian rhythm, emotional stress needs.

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A Study of Serum Lipid, Blood Sugar, Blood Pressure of Buddhist Nuns in Vegetarians and Non-Vegetarians (III) - Based on Age - (채식인과 비채식 일반인의 혈중 지질, 혈당, 혈압에 관한 연구(III) -연령을 중심으로-)

  • Cha, Bok-Kyeong
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.33 no.8
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    • pp.1311-1319
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    • 2004
  • The purpose of this study was to compare the serum lipid level, blood sugar and blood pressure in vegetarians and non-vegetarians. The subjects of the study were 127 Buddhist nuns (age: 23∼79 y) from Oonmoon Temple in Choungdo district Gyeongsang Bookdo province and 118 Buddhist nuns practicing Zen meditation at Soodeok Temple in Yeosan district Chongcheong Namdo province. For control subjects, 235 healthy female adults (age: 23∼79 y) were selected. They were the nurses in the Gyeongsang National University Hospital, teachers and housekeepers living in Jinju, Gyeongsang Namdo province. The period of this study was from October 1996 to February 1997. The contents were consisted of food consumption survey, anthropometric measurement, estimated amount of energy expenditure, physical activity and clinical examination. The mean ages of the subjects were 44.2 y for vegetarians and 40.5 y for non-vegetarians, respectively. Average body mass index (BMI) of vegetarians and non-vegetarians were 22.47 and 21.08, WHR 0.85 and 0.84, percentage of body fat 28.79 and 26.55 respectively. The average duration of vegetarian diet of the vegetarians was 13.16 y. Levels of total cholesterol, LDL-cholesterol, atherogenic index (AI), diastolic blood pressure, blood sugar and HDL-cholesterol were significantly higher (p<0.01) in non-vegetarians than those of vegetarians. In both of subjects, levels of TG, total cholesterol, LDL-cholesterol, atherogenic index (AI) and systolic blood pressure were significantly higher (p<0.01) with an increment of age and the vegetarians showed a lower ratio of rise than the non-vegetarians. Levels of serum TG, LDL-cholesterol and AI were utmost in the 60 s and declined in the 70 s. Consequently, vegetarian diet can be considerably effective in reducing the level of the risk factors causing cardiovascular disease.

Study on Press-drying of Italian Poplar Board and its Effect on Improvement of Wood Property (이태리포푸라재(材)의 건조성(乾燥性) 및 성질개선(性質改善)에 관(關)한 연구(硏究))

  • Jung, Hee Suk
    • Journal of Korean Society of Forest Science
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    • v.37 no.1
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    • pp.17-30
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    • 1978
  • Press drying was used on italian poplar (Populus euamericana) to find the profitable means of drying. This study was designed to investigate the process of platen drying considering core temperature, drying time, current moisture content, drying rate, shrinkage and recovery, and green volume specific gravity, equilibrium moisture content and dimensional stability of press dried material and air dried material, The drying tests were conducted using 1.5 centimeter thick material at platen temperature of $175^{\circ}C$. The results were summarized as follows. 1. Core temperature was divided into three stages of drying characterized by period initial heating, plateau temperature and rising core temperature. Plateau temperature was 114 to $119^{\circ}C$. 2. The following predicting equations of drying time(y) in different core temperatures were developed for initial thickness($x_1$), initial moisture content ($x_2$) and final moisture content ($x_3$) 3. The predicting equaltion of current moisture content(u) was log u=4.658-0.060t as funtion of drying time(t) and that of drying rate(r) was log r=-2.797-0.049t. Current moisture content and drying rate of air drying were shown in figure 2. 4. The predicting equation of shrinkage in thickness direction(y) was log y=1.933+0.038t as function of drying time(t), and that of expansion in width direction was $y=-0.692+0.043t-0.001t^2$. 5. Thickness shrinkage was increased more than proportional at to pressure increase. Width shrinkage and thickness recovery was greatest at 35psi. 6. Green volume specific gravity of press dried material was 25% greater than that of air dried material. But equilibrium moisture content of press dried material was less 24% than that of air dried material. Antishrinkage efficiency of press dried material were obtained 27.7%.

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Study on Convergence Using Carotid Ultrasonography in Metabolic Syndrome risk factor (경동맥초음파 검사를 활용한 대사증후군 인자의 융합연구)

  • Sung, Hyun-Ho;Yoon, Joon
    • Journal of the Korea Convergence Society
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    • v.6 no.6
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    • pp.195-200
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    • 2015
  • This study conducted a comprehensive health examination center in healthy adult subjects 47 people in the 30-55 age carotid ultrasound and a blood test and measurement physique is located in Gyeonggi Province in 2014, was analyzed in the same group between gender and age of the person hip circumference was higher than the 40s and 50s(p<0.05). Carotid ultrasound results showed differences in the 30s and 50s (p<0.05). CIMT and BMI, in CIMT showed a positive correlation with hip circumference (p<0.05). In addition, blood pressure and systolic blood pressure in the CIMT showed a positive correlation (p<0.05). In conclusion, in this study, we demonstrated a correlation between metabolic syndrome risk factor in carotid IMT, and continue to research needed for the diagnosis of diseases of the metabolic syndrome factor fusion research is utilizing ultrasound for a more qualitative disease diagnosis.

Maximum exercise in 20 men Common carotid artery blood flow velocity impact (20대 남성에서 최대운동이 뇌로가는 혈관인 총경동맥 혈류 속도에 미치는 영향)

  • Kim, Ji-Won
    • Journal of the Korean Society of Radiology
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    • v.3 no.4
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    • pp.5-12
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    • 2009
  • Arterial blood from the heart chonggyeong passed directly to the cerebral arteries and the blood circulation is important, especially in arteries that prevent blood flow there are several variables. Among the variables the average flow velocity, pulse index, and blood flow resistance and which variables, double maekbakjisuna systolic and diastolic blood flow resistance index at the maximum rate and blood pressure associated with this because they are important variables, The change of variables such as speed noehyeolryu There are observations about the non-invasive ultrasound measurements using Doppler noehyeolryu uses. Up to 20 men in the exercise of noeroganeun hyeolryuin chonggyeong arteries to increase blood flow rates can be found.

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Peformance Comparisons of CDMA, OFDM, and MC-CDMA with Inaccurate Channel Estimates and Low-SNR Environments (신호대잡음비가 낮고 부정확한 채널추정값을 가질 때의 CDMA, OFDM, MC-CDMA의 성능 비교)

  • Rim Minjoong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.1A
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    • pp.55-61
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    • 2005
  • Mobile communication systems are required not only to support high-data-rate transmissions in favorable channel conditions but also to be able to tolerate hostile environments possibly encountered by cellular communications. This paper compares CDMA(Code Division Multiple Access), OFDM(Orthogonal Frequency Division Multiplexing), and MC-CDMA(Multi-Carrier CDMA)with inaccurate channel estimates and low SNR environments. The equations and simulation results show that the performance losses in CDMA systems due to imprecise channel estimates are not considerable while frequency-hopping of OFDM systems can result in more than l0dB SNR losses. Also, this paper show that frequency-spreading of MC-CDMA can be very helpful for channel compensation performances than frequency-hopping or time-spreading of OFDM.

The Age-Related Trend in Blood Pressure and the Prevalence of Hypertension in Korean Adults (한국 성인의 연령에 따른 혈압변화 양상과 고혈압 유병률)

  • Lee, Dae-Taek;Lee, Yong-Soo
    • Journal of Life Science
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    • v.22 no.2
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    • pp.148-155
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    • 2012
  • A cross-sectional analysis of blood pressure (BP) changes and the current prevalence and distribution of hypertension among age groups in Korea were conducted. Systolic (SBP), diastolic (DBP), and pulse (PP) pressures were evaluated. Residents visiting a local Community Health Center for a health check-up and/or participating in the Health Promotion Program were included for the analyses. A total of 6,570 subjects (2,809 men, 3,761 women) were divided into five age groups: 30-39, 40-49, 50-59, 60-69, and $70\leq$ years. Comparisons were made between sex and among age groups. SBP and DBP were continuously elevated, while men showed higher levels than women until their mid-60s; then, the trend was reversed. DBP in men became elevated from their 30s, reaching the highest in the 40s then slowly decreasing. DBP in women increased up to their 40s and 50s, then reached a plateau. PP increased rapidly from the 50s in both sexes. The major contributor of age-related BP elevation may be large artery stiffness in men, particularly from their 50s, while the blood pressure elevation of women may relate to diverse factors including large artery stiffness, stroke volume, and ventricular ejection rate. The rapid elevation of PP after the 50s in both men and women could represent a risk of cardiovascular or coronary mortality, particularly with increasing age. The current data showed a higher rate of hypertension in both sexes compared to previous reports. When those with both high-normal BP and hypertension are looked at in combination, BP management of the target population should be drastically elevated.