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검색결과 1,271건 처리시간 0.027초

Materials and Electrochemistry: Present and Future Battery

  • Paul, Subir
    • Journal of Electrochemical Science and Technology
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    • 제7권2호
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    • pp.115-131
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    • 2016
  • Though battery chemistry and technology had been developed for over a hundred years back, increase in demand for storage energy, in the computer accessories, cell phones, automobile industries for future battery car and uninterrupted power supply, has made, the development of existing and new battery, as an emerging areas of research. With innovation of high energetic inexpensive Nano structure materials, a more energy efficient battery with lower cost can be competitive with the present primary and rechargeable batteries. Materials electrochemistry of electrode materials, their synthesis and testing have been explained in the present paper to find new high efficient battery materials. The paper discusses fundamental of electrochemistry in finding true cell potential, overvoltages, current, specific energy of various combinations of anode-cathode system. It also describes of finding the performance of new electrode materials by various experiments viz. i. Cyclic Voltammetry ii. Chronoamperometry iii. Potentiodynamic Polarization iv. Electrochemical Impedance Spectroscopy (EIS). Research works of different battery materials scientists are discussed for the development of existing battery materials and new nano materials for high energetic electrodes. Problems and prospects of a few promising future batteries are explained.

소아 급성 신부전증의 신장 대체 요법 (Renal replacement therapy in children with acute renal failure)

  • 백경훈
    • Clinical and Experimental Pediatrics
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    • 제50권10호
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    • pp.938-947
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    • 2007
  • Many dialysis modalities such as peritoneal dialysis (PD), hemodialysis (HD) and continuous hemofiltration or hemodialysis (CRRT) are available for the management of pediatric patients with acute renal failure (ARF). PD is a relatively simple, inexpensive modality and can be used in hemodynamically unstable patients. But, it may not be the optimal therapy for patients with severe volume overload or life threatening hyperkalemia. HD is the preferred modality for the treatment of severe volume overload, severe hyperkalemia, but it needs vascular access. Improvements in the HD equipment have allowed HD to be performend in small children. Recents technological improvements in CRRT therapies have enabled pediatric patients who are less stable to be treated. CRRT is becoming the preferred method of acute therapy in pediatric intensive care units. A sound knowledge of the underlying principles of dialysis and awareness of recent technological advancements in differnet dialysis modalities will hopefully result in improved management of children with ARF.

자장계를 이용한 인공위성의 자세결정 알고리즘 (Spacecraft Attitude Determination Algorithm Using Magnetometer)

  • 민현주;김인중;김진호;박춘배;용기력;이승우
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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    • pp.342-342
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    • 2000
  • We present 3-axis stabilized spacecraft attitude determination algorithm using the magnetometer. The magnetometer has been used as a reliable, light-weight and inexpensive sensor in attitude determination and reaction wheel momentum dumping system. Recent studies have attempted to use the magnetometer when other attitude sensor, such as star tracker, fails. The differences between the measured and computed the Earth's magnetic field components are spacecraft attitude errors. In this paper, we propose extended Kalman filter(EKF) to determine spacecraft attitude with the magnetometer data and gyro-measured body rates. We develop and simulate this algorithm using MATLAB/SIMULINK. This algorithm can be used as a backup attitude determination system.

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Skin Necrosis with Oculomotor Nerve Palsy Due to a Hyaluronic Acid Filler Injection

  • Lee, Jae Il;Kang, Seok Joo;Sun, Hook
    • Archives of Plastic Surgery
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    • 제44권4호
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    • pp.340-343
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    • 2017
  • Performing rhinoplasty using filler injections, which improve facial wrinkles or soft tissues, is relatively inexpensive. However, intravascular filler injections can cause severe complications, such as skin necrosis and visual loss. We describe a case of blepharoptosis and skin necrosis caused by augmentation rhinoplasty and we discuss the patient's clinical progress. We describe the case of a 25-year-old female patient who experienced severe pain, blepharoptosis, and decreased visual acuity immediately after receiving a filler injection. Our case suggests that surgeons should be aware of nasal vascularity before performing an operation, and that they should avoid injecting fillers at a high pressure and/or in excessive amounts. Additionally, filler injections should be stopped if the patient complains of severe pain, and appropriate measures should be taken to prevent complications caused by intravascular filler injections.

미세 스탬핑용 박판소재의 물성치 측정 (Measurement of Material Properties for Miniature Stamping)

  • 김양수;심현보
    • 소성∙가공
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    • 제15권3호
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    • pp.247-254
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    • 2006
  • Rather than traditional manufacturing processes, miniature manufacturing processes usually require sophisticated equipments and characteristics of the processes of high cost and of low productivity. Contrarily, miniature stamping process can be realized in a low cost high productivity with relatively inexpensive equipments. In the meso scale, mechanical properties, especially work hardening characteristics, are discovered to be statically scattered and size dependent by intensive experimental and numerical investigations, which make the stamping process hard to apply to the miniature manufacturing. In this study, dual purpose experimental device that can be used for both miniature scale tensile test and miniature scale stamping by simple change of attachment has been developed. For the tensile test, the elongation has been measured with a combined use of a CCD camera and a linear encoder in order to account for the possibility of slippage between specimen and the grip and to ensure the accuracy of the measurement, while load has been measured with a load cell. To satisfy the required material properties for stamping, optimal annealing condition has been found by examining the microstructure of annealed specimen.

A comparison of RPLA and PCR for detection of enterotoxins in methicillin-resistant Staphylococcus aureus(MRSA) strains isolated in dogs

  • Park, Son-il;Han, Hong-ryul
    • 대한수의학회지
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    • 제39권4호
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    • pp.806-810
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    • 1999
  • A multiplex-polymerase chain reaction (PCR) assay was used to detect staphylococcal enterotoxin production by 12 strains of Staphylococcus aureus isolated from clinical specimens. To evaluate the efficacy and/or sensitivity of this method, the results were compared to those obtained with the reversed passive latex agglutination kit (SET-RPLA, Denka Seiken, Japan). Of 10 strains positive by PCR were positive by RPLA but two strains, representing high sensitivity of the former method. Enterotoxin B was the most prevalent by the two methods. The kappa index between the two methods was 0.826, indicating a higher agreement and fully reliable for use. These results would suggest that sensitive, inexpensive, and relatively rapid multiplex-PCR technique may be an effective means for the detection of staphylococcal enterotoxin genes as an alternative to traditional methods such as kits or immunological methods, which depend upon the amount of enterotoxin produced.

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Some Way for Three-phase Induction Motors Electromagnetic Noise Reduction

  • Sarbu, Mircea A.
    • 소음진동
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    • 제13권2호
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    • pp.119-128
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    • 2003
  • Abstract Increasing awareness of industrial noise pollution and emerging stricter standards have made noise an important topic of research in electric motors. The standard three-phase induction motors. see Fig. 1, (abbreviated further as TPIM) are mass-produced as being simple, robust and rather inexpensive, as opposed to other types of electric motors. Electric motors use over half of all electricity consumed in most countries. Typically motors consume 60∼80 % of the electricity for those used In the industrial sector and about 20∼35 % of the electricity for those used in the commercial sector. For that is important to know their participation to the noise pollution of the environment and the efficient ways of their noise reduction. Each step in determining the ways for TPIM electromagnetic noise reduction including the methods that highlight their efficiency, are presented and explained.

친환경농산물의 속성별 상대평가 및 포지셔닝 전략 (Relative Evaluation to Its Attributes and Positioning Strategies for Environment-Friendly Agricultural Procucts)

  • 허승욱
    • 한국유기농업학회지
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    • 제12권2호
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    • pp.153-169
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    • 2004
  • This study attempted to identify relative evaluation to its attributes and improvement of consumer's demand in the Environment-Friendly Agricultural Products(EFAP). To identify the consumption patterns of EFAP, a series of household surveys were conducted for housewives residing in Seoul and its metropolitan area(Bundang and Ilsan). the sample size of the survey is 366 respectively. This study operated relative evaluation of EFAP by Multi-Demential Scales(MDS) about 10 attributes that this study set up. As the result, the consumers recognized that EFAP is "protection of ecosystem", "food safety", "good for growth of children", "high quality", and in case of conventional farming products is "inexpensive price", and "diversity of purchasing items". This trend has significant implications to the structure of EFAP output and how positioning strategies, and approaches should be properly formulated and implemented.

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초음파 속도법에 의한 현장 콘크리트 강도추정의 신뢰성 향상 (Reliability Improvement of In-Place Concreter Strength Prediction by Ultrasonic Pulse Velocity Method)

  • 원종필;박성기
    • 한국농공학회지
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    • 제43권4호
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    • pp.97-105
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    • 2001
  • The ultrasonic pulse velocity test has a strong potential to be developed into a very useful and relatively inexpensive in-place test for assuring the quality of concrete placed in structure. The main problem in realizing this potential is that the relationship between compressive strength ad ultrasonic pulse velocity is uncertain and concrete is an inherently variable material. The objective of this study is to improve the reliability of in-place concrete strength predictions by ultrasonic pulse velocity method. Experimental cement content, s/a rate, and curing condition of concrete. Accuracy of the prediction expressed in empirical formula are examined by multiple regression analysis and linear regression analysis and practical equation for estimation the concrete strength are proposed. Multiple regression model uses water-cement ratio cement content s/a rate, and pulse velocity as dependent variables and the compressive strength as an independent variable. Also linear regression model is used to only pulse velocity as dependent variables. Comparing the results of the analysis the proposed equation expressed highest reliability than other previous proposed equations.

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레이저 직접묘화방법을 이용한 광도파로 제작 (Optical Waveguide Fabrication using Laser Direct Writing Method)

  • 김정민;신보성;김재구;장원석
    • 한국정밀공학회지
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    • 제20권12호
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    • pp.42-47
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    • 2003
  • The laser direct writing method has some advantages of being maskless, allowing rapid and inexpensive prototyping in comparison to conventional mask-based photolithography. In general, there are two kinds of laser direct writing methods such as the laser ablation method and the laser polymerization method. The laser polymerization method was studied fur manufacturing waveguide in this paper. It is important to reduce line width for image mode waveguides, so some investigations will be carried out in various conditions of process parameters such as laser power, writing speed, focusing height and optical properties of polymer. Experimentally, the optical waveguide was manufactured trapezoid shape. Through SEM the waveguide was 20 ${\mu}{\textrm}{m}$ width and 7.4 ${\mu}{\textrm}{m}$ height.