• Title/Summary/Keyword: 과학실

Search Result 1,337, Processing Time 0.031 seconds

특별기고 - 과학기술 발전의 허와 실

  • Im, Gyeong-Sun
    • The Science & Technology
    • /
    • v.30 no.11 s.342
    • /
    • pp.20-21
    • /
    • 1997
  • 인류사에서 과학기술의 역할은 갈수록 커지고 있다. 1939년 DDT가 개발되어 놀라운 살충효과가 확인되었는가 하면 1945년 투하된 원자탄은 우리 사회에 엄청난 충격을 주었고 1953년 이후 유전공학분야의 연구가 급속히 진전되었지만 새로운 유전자조작으로 인간복제의 경지에까지 이르자 생명윤리에 대한 논쟁을 불러 일으키고 있다. 과학기술이 인류사에 긍정적이냐, 부정적이냐 하는 문제가 인간윤리의 벽 앞에서 새롭게 고민하고 있다.

  • PDF

Characteristics of Spectral Reflectance for Corns and Legumes at OSMI(Ocean Scanning Multi-spectral Imager) Bands (OSMI 파장영역에서 옥수수와 두류작물의 분광반사특성)

  • 홍석영;임상규;황선주;김선오
    • Korean Journal of Remote Sensing
    • /
    • v.14 no.4
    • /
    • pp.343-352
    • /
    • 1998
  • Spectral reflectance data of upland crops at OSMI bands were collected and evaluated for the feasibility of crop discrimination knowledge-based on crop calendar. Effective bands and their ratio values for discriminating corn from two other legumes were defined with OSMI equivalent bands and their ratio values. For corn discrimination from two other legumes, peanut and soybean, June 22 among measurements dates was the best since all OSMI equivalent bands and their ratio values in June 22 were highly significant for corn separability. Phenological growth stage of a silage corn (rs510) could be estimated as a function of spectral reflectance in vegetative stage. Five growth stage prediction models were generated by the SAS procedures REG and STEPWISE with OSMI equivalent bands and their ratio values in vegetative stage.

A Study on the Demographic Characteristics of Lifestyle Cluster Types and the Characteristics of the Use of Hair Salons (라이프스타일 군집유형에 따른 인구통계학적 특성과 미용실이용 특성에 대한 연구)

  • Kim, In-Ok;Jeon, Jong-Chan
    • Journal of the Korean Applied Science and Technology
    • /
    • v.37 no.5
    • /
    • pp.1418-1429
    • /
    • 2020
  • This study was conducted on men and women in their teens and 50s living in Seoul, Incheon and Gyeonggi-do to find out the relevance between demographic characteristics of lifestyle clusters and the characteristics of beauty salon use. To analyze the data of a total of 522 people collected, statistical processing was performed with analysis of frequency, analysis of factor, analysis of reliability, analysis of cluster, analysis of variance and analysis of cross. As a result, lifestyle group types were classified as fashion and social focus types, family-oriented types, and family-free types. These types were highly related to age, final education, and marital status among demographic characteristics, and were also found to be highly relevant to the characteristics of beauty salon use, such as beauty salon location and frequently used beauty services. The results of this study are thought to be the basic data that can be used for beauty salon marketing.

Renoprotective Effect of Maydis Stigma on Puromycin Aminonucleoside-induced Nephrotic Syndrome (Puromycin Aminonucleoside에 의해 유도된 신증후군에 대한 옥미수(玉米鬚)의 보호효과)

  • Yoon, Jung-Joo;Kho, Min-Chol;Han, Byung-Hyuk;Kim, Hye-Yoom;Ahn, You-Mee;Lee, Yun-Jung;Lee, Ho-Sub;Kang, Dae-Gill
    • The Journal of Korean Obstetrics and Gynecology
    • /
    • v.34 no.4
    • /
    • pp.1-11
    • /
    • 2021
  • Objectives: Nephrotic syndrome is a kidney disorder, which is characterized by proteinuria, edema (swelling), and hyperlipidemia. Maydis Stigma (Corn silk) has been widely used in Asia as a traditional medicine and is known to have a diuretic effect and is used for the treatment of edema and indigestion. Methods: The aim of this study is to investigate the improvement effect of Maydis Stigma in treating nephrotic syndrome induced by puromycin aminonucleoside. Sprague-Dawley rats were intravenously injected with 75 mg/kg/day puromycin aminonucleoside, then treated with either Losartan or 200 mg/kg/day Maydis Stigma for seven days. Results: Maydis Stigma significantly decreased ascites and proteinuria level. Plasma levels of blood urea nitrogen (BUN) and plasma creatinine reduced significantly by Maydis Stigma. In addition, treatment with Maydis Stigma attenuated histological damage. Treatment with Maydis Stigma also restored podocin expression and reduced inflammation markers such as intracellular adhesion molecules (ICAM-1), monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor alpha (TNF-α) and high-mobility group box-1 (HMGB1). Conclusions: Maydis Stigma ameliorates kidney injury in nephrotic syndrome rat models. Maydis Stigma exerts a renoprotective effect owing to its anti-inflammatory effects and reductions of ascites and proteinuria. Thus, these results indicate that Maydis Stigma is likely to be a promising agent in the treatment of nephrotic syndrome.

Estimation of bulk flow resistance in vegetated channels based on large-scale river experiments (실규모 하천 실험을 통한 식생하도의 구간 흐름저항 산정)

  • Ji, Un;Bae, Inhyeok;Ahn, Myeonghui;Jang, Eun-kyung
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2021.06a
    • /
    • pp.3-3
    • /
    • 2021
  • 하천의 식생은 생태서식처 제공, 강턱이나 하안 경사의 안정, 영양염류나 오염물 차단에 의한 수질 개선 등의 다양한 생태서비스를 제공하는 반면, 과도하고 편중된 식생 분포로 인해 흐름저항이 증가하고 이로 인한 홍수위 상승과 홍수피해 위험이 가중될 수 있다. 기후변화 영향과 토지이용 변화에 따른 수리수문 특성 변화와 유역으로부터 영양염류의 유입은 하천내 식생이 과도하게 퍼지는 직접적인 원인이 될 수 있다. 과도한 식생분포로 인한 흐름저항과 홍수위 상승을 평가하기 위해 식생하도의 흐름저항과 관련된 매개변수의 다양성과 복잡성에 따른 해석상의 한계에도 불구하고 이에 대한 이론적 해석과 수학모형의 개발, 실험실 수로와 하천현장조사, 수치모형을 이용한 예측 등의 다양한 연구가 수행되고 있다. 본 연구에서는 소규모 실험실 수로에서 단순화된 식생 구조와 배열이 적용되는 한계성과 상류에서 유입되는 유량과 유속 등의 수리조건을 통제할 수 없는 현장실험의 한계성을 보완하고자 목본류 형태의 식생패치를 실규모 하천실험 수로에 조성하여 통제된 수리조건에서의 식생하도의 구간 흐름저항을 추정하기 위한 계측 실험을 수행하였다. 실규모 실험에서는 피에조미터 형식의 정밀 압력식 센서를 이용하여 수위와 수면경사를 계측하였으며, 실험구간의 접근 수로에서 ADCP(Acoustic Doppler Current Profiler)를 이용하여 유입 유량에 대한 정보를 수집하였다. 전체 수로 길이 약 600 m, 하폭 11 m, 깊이 2 m 규모의 실규모 하도 일부 80 m 완경사 구간에 식생패치를 설치하고 구간 수면경사를 실측함으로써 식생하도의 흐름저항을 직접 산정하였다. 이러한 실규모 식생하도의 실험을 통해 식생패치의 밀도, 횡적 차단면적, 구간 차단부피, 목본 식생의 물리적 특성, 식생패치의 배열 등의 다양한 식생분포 조건에 따른 수리조건별 흐름저항 값의 변화를 분석할 수 있다. 식생하도에 대한 정확한 흐름저항 추정과 홍수위 변화에 대한 해석은 하천 식생의 생태서비스와 홍수방어의 하천 치수효과의 최적 솔루션을 제시하기 위한 하도관리의 다양한 방안을 제시하는데 필수적인 정보로 활용될 수 있다.

  • PDF

Studies on Strength of Netting (1) The Decrease in Strength of Netting Twines by Knotting (그물감의 강도에 관한 연구 (1) 그물실의 강도가 매듭에서 감소하는 기구)

  • KIM Dai An
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.9 no.1
    • /
    • pp.1-7
    • /
    • 1976
  • 1) The decrease in strength of netting twines at the knot may be regarded to be due mainly to the frictional force acting on the tip of the knot. The knot strength T may be given by $$T=\frac{T_0}{1+{\mu}\frac{s}{\rho}\varrho^{\mu\theta}$$ were $T_0$ is the tensile strength of unknotted netting twines, $\mu$ the coefficient of friction beween two netting twines forming a knot, s the contact length between the tip and the netting twine compressing it, $\rho$ the radius of curvature of the compressing, and $\theta$ the angle at which the compressing rubs with another one in the vicinity of the opposite tip. 2) Knots are arranged in order of strength as follows : the reef knot pulled lengthwise $\risingdotseq$ the trawler knot pulled breadtwise the reef knot pulled breadthwise.

  • PDF

Diagnosis of tooth wear (치아마모의 진단)

  • Lee, Hyeseon;Ko, Kyung-Ho;Huh, Yoon-Hyuk;Park, Chan-Jin;Cho, Lee-Ra
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.35 no.3
    • /
    • pp.113-122
    • /
    • 2019
  • Tooth wear is gradually increasing with increasing life expectancy. In particular, it is important to establish a treatment plan in the early stages so that it does not proceed to moderate or severe wear stages. It is essential to diagnose tooth wear accurately in order to plan a treatment for it. There are many risk factors including age, diet, and drugs which affects tooth wear. For the diagnosis of a tooth wear, appropriate index and evaluation method should be used. There were various tooth wear indices such as TWI, Lussi index, BEWE, and TWES. The evaluation method includes clinical examination, dental cast examination and clinical photographs. Recently, a 3D scanner is being used to assess tooth wear. The risk factors, tooth wear evaluation system, the methods of measuring tooth wear, and related literature were reviewed. The strengths and weaknesses of each index and evaluation methods were compared to derive a proper way to diagnose tooth wear.