• 제목/요약/키워드: high-Q

검색결과 2,363건 처리시간 0.026초

참나무속 3종의 유식물 정착과 생장의 비교에 대한 실험적 연구 (An Experimental Study on the Comparison of the Establishment and Growth of Seedlings among Three Oak Species)

  • Baek, Myeong-Su;Do-Soon Cho
    • The Korean Journal of Ecology
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    • 제19권2호
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    • pp.125-139
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    • 1996
  • The relationships between environmental factors and the establishment and growth of oak seelings were studied in the greenhouse. The early seedling performances of three oak species (Quercus mongolica, Quercus serrata, Quercus variabilis) were compared. Mean seed weight was the biggest in Q. variabilis, and the smallest in Q. serrata, and the germination rate was higher in Q. variabilis than in Q. mongolica and Q. serrata. The germination rate was significantly affected by seed weight class in Q. serrata, but not in Q. mongolica. Emergence of oak seedlings was similar in all three oak species, and especially the first leaf emergence increased about twenty days after germination. An experiment was designed using three environmental factors (light, soil moisture, fertilizer) to compare the response of the three oak species. Light and soil moisture significantly affected the seedling height growth of Q. variabilis, but the effect was marginal in Q. mongolica and Q. serrata. However, growth of seedling biomass was significant in all three oak species. In contrast, fertilizer did not affect seedling growth of any of the oak species. Q. variabilis is expected to grow well in large gaps because it is very sensitive and responds well to high light and high moisture conditions. Q. mongolica and Q. serrata are relatively tolerant to shade but may need gaps for the seelings to grow into saplings.

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Passively Q-switched Erbium Doped All-fiber Laser with High Pulse Energy Based on Evanescent Field Interaction with Single-walled Carbon Nanotube Saturable Absorber

  • Jeong, Hwanseong;Yeom, Dong-Il
    • Current Optics and Photonics
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    • 제1권3호
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    • pp.203-206
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    • 2017
  • We report a passive Q-switching of an all-fiber erbium-doped fiber laser delivering high pulse energy by using a high quality single-walled carbon nanotube saturable absorber (SWCNT-SA). A side-polished fiber coated with the SWCNT is employed as an in-line SA for evanescent wave interaction between the incident light and the SWCNT. This lateral interaction scheme enables a stable Q-switched fiber laser that generates high pulse energy. The central wavelength of the Q-switched pulse laser was measured as 1560 nm. A repetition rate frequency of the Q-switched laser is controlled from 78 kHz to 190 kHz by adjusting the applied pump power from 124 mW to 790 mW. The variation of pulse energy from 51 nJ to 270 nJ is also observed as increasing the pump power. The pulse energy of 270 nJ achieved at maximum pump power is 3 times larger than those reported in Q-switched all-fiber lasers using a SWCNT-SA. The tunable behaviors in pulse duration, pulse repetition rate, and pulse energy as a function of pump power are reported, and are well matched with theoretical expectation.

High-Q MEMS Spiral Inductor를 이용한 RF VCO (RF VCO with High-Q MEMS-based Spiral Inductor)

  • 김태호;김경만;서희원;황인석;김삼동
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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    • pp.987-990
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    • 2003
  • This paper presents a cross-coupled RF VCO with high-Q MEMS-based spiral inductors. Since the use of high-Q inductors is critical to VCO design, MEMS-based spiral inductors with the Q-factor of nearly 22 are used for the RF VCO with an active cascode current source. The RF VCO circuits including spiral inductors have been designed and simulated in GaAs MMIC-MEMS process. The simulation results of the VCO circuits showed the phase noise of -180dBc/Hz at an offset frequency of 500KHz. The RF VCO circuit simulatinon used 2mA DC current and 3.3V supply.

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Safety, High Quality, Confidence of Kaneka CoQ10

  • Fujii, Kenji
    • 한국응용약물학회:학술대회논문집
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    • 한국응용약물학회 2006년도 Proceedings of The Convention
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    • pp.139-145
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    • 2006
  • Kaneka Corporation (Kaneka) has been manufacturing CoQ10 under GMP regulation since 1977. Kaneka has a sophisticated quality control system and has been supplying high quality CoQ10 materials to the worldwide customers (Kaneka CoQ10) for about 30 years. Kaneka CoQ10 is characterized by a lot of safety data, which are derived from clinical trials with healthy volunteers (single-dose and 4-week multi-dose safety studies), animal studies (13-week sub-chronic study in dogs and 52-week chronic study in rats), three types of mutagenicity test, six type of skin irritation test (for cosmetics), and others. The risk assessment of CoQ10 was performed by Council for Responsible Nutrition (USA). They reviewed many of available clinical data including clinical trials using Kaneka Q10, and concluded that the upper level for supplements (ULS) of CoQ10 is 1,200 mg/day (Hathcock and Shao. 2006, Regulatory Toxicology and Pharmacology, 45, 282 - 288).

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Safety, High Quality, Confidence of Kaneka CoQ10

  • Fujii, Kenji
    • 한국약용작물학회:학술대회논문집
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    • 한국약용작물학회 2006년도 Proceedings of The Convention of The Korean Society of Applied Pharmacology
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    • pp.139-145
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    • 2006
  • Kaneka Corporation (Kaneka) has been manufacturing CoQ10 under GMP regulation since 1977. Kaneka has a sophisticated quality control system and has been supplying high quality CoQ10 materials to the worldwide customers (Kaneka CoQ10) for about 30 years. Kaneka CoQ10 is characterized by a lot of safety data, which are derived from clinical trials with healthy volunteers (single-dose and 4-week multi-dose safety studies), animal studies (13-week sub-chronic study in dogs and 52-week chronic study in rats), three types of mutagenicity test, six type of skin irritation test (for cosmetics), and others. The risk assessment of CoQ10 was performed by Council for Responsible Nutrition (USA). They reviewed many of available clinical data including clinical trials using Kaneka Q10, and concluded that the upper level for supplements (ULS) of CoQ10 is 1,200mg/day (Hathcock and Shao. 2006, Regulatory Toxicology and Pharmacology, $\underline{45}$, 282 - 288).

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고등학생들의 자살에 대한 태도 유형 - Q방법론적 접근 - (Types of Attitude toward Suicide in High School Students: A Q-Methodology Approach)

  • 최혜정;이종화;정혜경;권성복
    • 한국보건간호학회지
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    • 제25권2호
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    • pp.276-288
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    • 2011
  • Purpose: The rate of suicide is rising most rapidly among high school students. Teenage suicide is no longer just a personal problem. This study investigated and classified high school students concerning in South Korea with an aim of identifying suicidal ideation and types of teenage suicide. Method: A Q-methodology was used to identify factors in suicidal attitude of high school students. A Q-sample was collected from in-depth and objective interviews and literature reviews. A P-sample consisted of 37 high school students : selected Q-samples were sorted on a 9-point scale. Results: Three types of suicidal attitudes were evident among high school students : abomination(Type 1), understanding of the situation (type 2), and social responsibility(type 3). Conclusion: Precautionary measures against high school students suicide should be formulated according to the types of attitudes toward suicide in south Korea.

실제적 함의에 대한 학생들의 이해 (Students' understandings of material implication)

  • 박달원
    • 한국학교수학회논문집
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    • 제17권4호
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    • pp.805-816
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    • 2014
  • 본 연구에서는 형식적 함의에 대한 역사적 발달과정을 살펴보고 형식적 함의에 대하여 대학생들이 어떻게 이해하는지를 분석하였다. 또한 고등학생들과 예비대학생들을 대상으로 카드모임에 대한 실제적 함의에 대하여 조사한 결과 주어진 카드 모음에서 성립하는 패턴을 명제 $p{\rightarrow}q$로 나타낼 때에는 명제 $p{\rightarrow}q$${\sim}p{\vee}q$와 동치인 명제로 이해하는 학생들이 가장 많았지만 명제 $p{\rightarrow}q$가 성립하는 카드를 모으는 과정에서는 조건명제 $p{\rightarrow}q$$p{\wedge}q$와 동치인 명제로 이해하는 학생들이 가장 많은 것으로 조사되었다.

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Effect of Coenzyme Q10 Supplementation in Statin-Treated Obese Rats

  • Choi, Hye-Kyung;Won, Eun-Kyung;Choung, Se-Young
    • Biomolecules & Therapeutics
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    • 제24권2호
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    • pp.171-177
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    • 2016
  • Statins, HMG-CoA reductase inhibitors, are known to cause serious muscle injuries (e.g. myopathy, myositis and rhabdomyolysis), and these adverse effects can be rescued by co-administration of coenzyme $Q_{10}$ ($CoQ_{10}$) with statins. The goal of the current research is to assess the efficacy of combined treatment of $CoQ_{10}$ with Atorvastatin for hyperlipidemia induced by high-fat diet in SD rats. 4-week-old Sprague-Dawley male rats were fed normal diet or high-fat diet for 6 weeks. Then, rats were treated with either Statin or Statin with various dosages of $CoQ_{10}$ (30, 90 or 270 mg/kg/day, p.o.) for another 6 weeks. Compared to Statin only treatment, $CoQ_{10}$ supplementation significantly reduced creatine kinase and aspartate aminotransferase levels in serum which are markers for myopathy. Moreover, $CoQ_{10}$ supplementation with Statin further reduced total fat, triglycerides, total cholesterol, and low-density lipoprotein-cholesterol. In contrast, the levels of high-density lipoprotein-cholesterol and $CoQ_{10}$ were increased in the $CoQ_{10}$ co-treated group. These results indicate that $CoQ_{10}$ treatment not only reduces the side effects of Statin, but also has an anti-obesity effect. Therefore an intake of supplementary $CoQ_{10}$ is helpful for solving problem of obese metabolism, so the multiple prescription of $CoQ_{10}$ makes us think a possibility that can be solved in being contiguous to the obesity problem, a sort of disease of the obese metabolism.

높은 대역폭 효율과 정진폭 신호 전송을 위한 CACB-Q2AM 변조 (CACB-Q2AM Modulation for High Bandwidth Efficiency and Constant Amplitude Signal Transmission)

  • 홍대기;강성진
    • 인터넷정보학회논문지
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    • 제9권1호
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    • pp.21-32
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    • 2008
  • 본 논문에서는 정진폭 신호 특성을 갖는 기존의 정진폭 부호화된 다중 부호 이진 직교 (CACB: Constant Amplitude Coded Multicode Biothogonal) 변조의 구조를 유지하면서 대역폭 효율을 증가시킴으로써 전송률을 높일 수 있는 방식을 제안한다. 높은 대역폭 효율을 얻기 위한 방식으로는 기존에 제안되었던 직교위상-직교위상 진폭변조 ($Q^2$AM: Quadrature-Quadrature Amplitude Modulation), 그리고 정진폭 직교위상직교위상 진폭변조 ($CA-Q^2$AM: Constant Amplitude-$Q^2$AM) 방식을 이용한다. 먼저 가장 간단한 결합 방식인 CACB-$Q^2$AM 방식을 제안한다. 이 방식은 대역폭 효율은 증가하지만 정진폭 특성을 얻을 수는 없기 때문에 정진폭 특성을 유지하기 위한 새로운 첫 번째 CACB-CA-$Q^2$AM (CACB-CA-$Q^2$AM I) 변조 방식을 제안한다. 그러나 이 방식은 정진폭을 얻기 위해 여분의 부호화 과정이 필요하므로 대역폭 효율이 낭비되는 단점이 있다. 마지막으로 대역폭 효율을 감소시키지 않는 새로운 두 번째 CACB-CA-$Q^2$AM (CACB-EA-$Q^2$AM II) 변조 방식을 제안한다. 컴퓨터모의실험을 통해 제안된 시스템의 성능을 평가함으로서 제안된 CACB-CA-$Q^2$AM II 변조 방식의 효율성을 보이도록 한다.

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Estimating the Queue Length Distribution of ATM multiplexer using Threshold Bootstrap

  • 김윤배
    • 한국시뮬레이션학회:학술대회논문집
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    • 한국시뮬레이션학회 1999년도 추계학술대회 논문집
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    • pp.62-62
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    • 1999
  • In this paper, we propose a new technique of estimating tail of steady-state queue length distribution; Pr(Q>q), fo ATM multiplexer. Pr(Q>q) is a fundamental measure of network congestion. Assessing Pr(Q>q) properly is crucial for design and control of ATM networks. Data traffic pattern of high-speed networks is highly correlated and bursty. Estimating Pr(Q>q) is very difficult because of correlation and burstiness. We estimate entropy(rate-function) using large deviation principles and threshold bootstrap. Simulation studies are conducted to compare the performance of an existing method and our new method.

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