• 제목/요약/키워드: alternating field

검색결과 222건 처리시간 0.027초

Management of Powdery Mildew in Squash by Plant and Alga Extract Biopesticides

  • Zhang, Shouan;Mersha, Zelalem;Vallad, Gary E.;Huang, Cheng-Hua
    • The Plant Pathology Journal
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    • 제32권6호
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    • pp.528-536
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    • 2016
  • Although many fungicides are registered for use to control powdery mildew on cucurbits, management of resistance to fungicides in pathogen populations still remains a major challenge. Two biopesticides Regalia SC and HMO 736 were evaluated in the greenhouse and field for their efficacy against powdery mildew in squash. In greenhouses, Regalia SC alone significantly (P < 0.05) reduced powdery mildew compared to the nontreated control, and was as effective as the chemical standard Procure 480SC (triflumizole). In alternation with Procure 480SC, Regalia SC demonstrated greater or equivalent effects on reducing the disease. HMO 736 alone showed varying levels of disease control, but alternating with Procure 480SC significantly improved control efficacy. In addition, application of Regalia SC or HMO 736 each in alternation with Procure 480SC significantly increased the chlorophyll content in leaves and the total fresh weight of squash plants, when compared with the water control, Regalia SC and HMO 736 alone. In field trials, application of Regalia SC and HMO 736 each alone significantly reduced disease severity in one of two field trials during the early stage of disease development, but not during later stages when disease pressure became high. Both Regalia SC and HMO 736 each applied in alternation with Procure 480SC significantly improved the control efficacy compared to Procure 480SC alone. Results from this study demonstrated that an integrated management program can be developed for powdery mildew in squash by integrating the biopesticides Regalia SC, HMO 736 with the chemical fungicide Procure 480SC.

FeMn/NiFe에서 Laser 열처리에 의한 자구연구 (Magnetic Domain Structure in Laser-Annealed NiFe/FeMn Bilayers)

  • 최상대;김선욱;진대현;이미선;안진희;주호완;김영식;이기암;이상석;황도근
    • 한국자기학회지
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    • 제14권6호
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    • pp.224-227
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    • 2004
  • 교환결합된 NiFe/FeMn 이중박막에서 Laser 열처리를 통하여 국소적인 자화반전을 연구하였다. 600 G의 외부 자기장을 시편에 가하면서 DPSS Laser로 자화 반전시켰으며, 300 mW에서 15분 동안 국소적인 부분을 조사하였다. 국소적으로 자화반전 시킨 박막을 다시 원래 방향으로 역 반전시켜 자기저항(MR)곡선 피크가 감소된 것을 관찰하였다. 이는 직접적으로 Laser를 가한 박막의 손상과 계면에서 내부 확산에 의한 것으로 생각된다 국소적인 반전 자화의 자구구조는 MU을 통하여 관찰하였다. 자화반전 영역에서 새로운 자구벽을 형성하였으며, Laser가 조사된 영역근처에서 자구벽이 형성된 것을 관찰하였다.

A Comparison of Electrical Stimulation for Electrodic and EDTA-Enhanced Phytoremediation of Lead using Indian Mustard (Brassica juncea)

  • Lim, Jae-Min;Jin, Biao;Butcher, David J.
    • Bulletin of the Korean Chemical Society
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    • 제33권8호
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    • pp.2737-2740
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    • 2012
  • The use of plants to remove toxic metals from soil (phytoremediation) is emerging as a cost-effective alternative to conventional methods for the removal of heavy metals from contaminated soil. Indian mustard (Brassica juncea) was used as the plant to accumulate high tissue concentrations of lead when grown in contaminated soil. For this study, the application of an electric field combined effectively with EDTA-enhanced phytoremediation. A stimulation of direct and alternating electric potential was compared and EDTA-enhanced phytoremediation of lead using Indian mustard has been performed. The effects of experimental parameters such as operating voltage with different concentration of EDTA, the number of graphite electrodes, and cultivation period on the removal of toxic metal were studied. Shoot lead accumulations in Indian mustard increased as the concentration of EDTA and dc electric potential was increased. Two to four folds was increased when EDTA plus a dc electric potential was applied, compared to an ac electric potential. The maximum lead accumulation in the shoots was achieved by applying EDTA plus dc electric potential with 6 graphite electrodes.

평행평판 내의 지주에 의한 와동 유동에 관한 수치해석 (Numerical Computation of Vertex Behind a Bluff Body in the Flow between Parallel Plates)

  • 김동성;유영환
    • 대한기계학회논문집
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    • 제16권6호
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    • pp.1163-1170
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    • 1992
  • 본 연구에서는 자동차 전자제어식 공기유량계를 Fig.2와 같이 평행평판 안에 사각 지주가 있다고 단순화하고 공기는 이차원 비 압축성 점성유동으로 가정했다. 지배방정식은 유체 운동량방정식(navier-Stokes equation)을 와도 전달 방정식(vorti- city transport equation)과 유량 함수 방정식(stream function equation)으로 변환하 여 사용하였다. Peacemanrachford ADI 방법으로 수치해석 하였으며, 유량 함수 방정 식의 수렴성을 좋게 하기 위하여 Wachspress parameter를 사용하였다. 벽면의 경계 조건은 Briely의 4th-order Lagrange interpolation 방법을 따랐다. Reynolds 수 200과 500에서의 비정상유동(unsteady flow)을 계산하였으며, 유동이 정상상태(steady state)에 도달하였을 때에 유동을 교란시켜 와동 흘림(vortex shedding)을 구하였다.

정적 하중하의 굽힘 압전 복합재료 작동기의 작동 성능 (Actuating Performance of a Bending Piezoelectric Composite Actuator with a Thin Sandwiched PZT Plate under Static Loads)

  • 우성충;박기훈;구남서
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회A
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    • pp.1231-1236
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    • 2007
  • This study presents the static and dynamic actuating performances of a bending piezoelectric actuator with a thin sandwiched PZT plate under a static load. The stored elastic energy within the actuators which occurs during a curing process is obtained through a flexural bending test. An actuating performance is evaluated in terms of an actuating displacement at the simply supported condition. The results reveal that an actuator that consists of a top layer having a high elastic modulus and a low coefficient of thermal expansion exhibits a better performance than the rest of actuators due to the formation of the large stored elastic energy within the actuator system. When actuators are excited at the alternating current voltage, the effect of PZT ceramic softening results in a slight reduction in the resonance frequency of each actuator as the applied electric field increases. It is thus suggested that the static and dynamic actuating characteristics of bending piezoelectric actuators with a thin sandwiched PZT plate should be simultaneously considered in controlling their performances.

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Bluetooth Low-Energy Current Sensor Compensated Using Piecewise Linear Model

  • Shin, Jung-Won
    • 센서학회지
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    • 제29권5호
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    • pp.283-292
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    • 2020
  • Current sensors that use a Hall element and Hall IC to measure the magnetic fields generated in steel silicon core gaps do not distinguish between direct and alternating currents. Thus, they are primarily used to measure direct current (DC) in industrial equipment. Although such sensors can measure the DC when installed in expensive equipment, ascertaining problems becomes difficult if the equipment is set up in an unexposed space. The control box is only opened during scheduled maintenance or when anomalies occur. Therefore, in this paper, a method is proposed for facilitating the safety management and maintenance of equipment when necessary, instead of waiting for anomalies or scheduled maintenance. A Bluetooth 4.0 low-energy current-sensor system based on near-field communication is used, which compensates for the nonlinearity of the current-sensor output signal using a piecewise linear model. The sensor is controlled using its generic attribute profile. Sensor nodes and cell phones used to check the signals obtained from the sensor at 50-A input currents showed an accuracy of ±1%, exhibiting linearity in all communications within the range of 0 to 50 A, with a stable output voltage for each communication segment.

진주 및 고령 지역에 분포하는 신라역암층의 잔류자화에 대한 고지자기 연구 (Paleomagnetic Study on the Remanent Magnetization of the Silla Conglomerate Formation in Jinju and Goryeong Areas)

  • 김태성;민경덕;이윤수;이영훈;이동영
    • 자원환경지질
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    • 제31권4호
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    • pp.325-338
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    • 1998
  • 105 oriented samples (19 matrix samples, 86 cobble samples) were collected from the Silla Coglomerate Formation in Jinju and Goryeong areas to clarify the regional remagnetization of Cretaceous Kyongsang supergroup. Both the alternating field and thermal demagnetizations were conducted for the collected samples. The characteristic remanent magnetizations of these samples divided into three types in the Silla Conglomerate Formation: The ingredient magnetic minerals are magnetite, hematite, or both magnetite and hematite in a specimen. The characteristic remanent directions of cobble samples did not clustered to any direction. And the characteristic remanent directions of interbedded sandstones in the Silla Conglomerate Formation is $D/I=20.6^{\circ}/54.5^{\circ}$ (${\alpha}_{95}=11.1^{\circ}$, k=48.8) after tilting correction, agree with previous paleomagnetic studies on the Hayang group. These results implied that conglomerate test was passed indicating no regional remagnetization in the studied area after deposition of the Silla Conglomerate Formation.

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자속밀도 파형제어에 의한 토로이달 벌크 전기강의 자기특성 측정 (Experimental Measurement of Magnetic Properties of a Toroidal-type Bulk Electrical Steel using B-waveform Control)

  • 음영환;고창섭;홍선기;신판석
    • 전기학회논문지
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    • 제56권5호
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    • pp.869-875
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    • 2007
  • Magnetic properties of electrical steel are, in general. measured by using Epstein frame or single sheet tester (SST). These methods, however, require very strict regulation of a specimen in its size and shape. thus, can not be easily applied to various types of specimen. On the other hand, a ring-test method, which measures only the isotropic properties, can be easily applied to most cases because it requires a toroidal-type specimen of arbitrary size. This method, especially, is considered as an unique available method for a bulk-type specimen. In this paper, a ring-test method is developed, and applied to the measurement of magnetic properties of a bulk-type electrical steel with a toroidal-type specimen. In the measurement, the magnetic properties and iron losses are measured and compared with each other at the both sinusoidal magnetic flux density and sinusoidal magnetic field intensity conditions under 0.2Hz and 60Hz alternating magnetic fields excitation. Through experimental measurements, a sinusoidal magnetic flux density condition is proven appropriate for the measurement of magnetic properties, including iron loss characteristics, of electrical steels.

소구경 개인화기 격발신호 발생장치의 자기차폐효과 분석 (Magnetic-Shielding Effectiveness Analysis of the Trigger Assembly of Small Arms)

  • 이기수;안준모;채제욱
    • 한국군사과학기술학회지
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    • 제21권4호
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    • pp.456-463
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    • 2018
  • With the development of weapon systems by mounting various sensors, it makes important to analyze the precise functioning of sensor to external environment. In the case of small arms with magnetic sensor, the malfunction of small arms might be caused by strong external magnetic fields. In this study, the effects of magnetic sensor on external magnetic fields were analyzed, and optimal magnetic shield and shield structure were designed through M&S. In addition, the magnetic-shielding effectiveness of magnetic sensor in small arms was verified with commercial shielding materials. As a result, it was demonstrated that the Fe-Cu-Si-Nd-B with the structure of multi-layer metallic shields was shown the magnetic-shielding effectiveness of 83 % for an external permanent magnet and 19 % for an alternating magnetic field of 180 dBpT at 60 Hz, respectively.

강도함수가 감소패턴을 따르는 NHPP 소프트웨어 신뢰모형에 관한 비교 연구 (A Comparative Study on Software Reliability Model for NHPP Intensity Function Following a Decreasing Pattern)

  • 김희철;김정범;문송철
    • Journal of Information Technology Applications and Management
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    • 제23권4호
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    • pp.117-125
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    • 2016
  • Software reliability in the software development process is an important issue. In infinite failure non-homogeneous Poisson process software reliability models, the failure occurrence rates per fault. can be presented constant, monotonic increasing or monotonic decreasing pattern. In this paper, the reliability software cost model considering decreasing intensity function was studied in the software product testing process. The decreasing intensity function that can be widely used in the field of reliability using power law process, log-linear processes and Musal-Okumoto process were studied and the parameter estimation method was used for maximum likelihood estimation. In this paper, from the software model analysis, we was compared by applying a software failure interval failure data considering the decreasing intensity function The decreasing intensity function model is also efficient in terms of reliability in the arena of the conservative model can be used as an alternating model can be established. From this paper, the software developers have to consider life distribution by preceding information of the software to classify failure modes which can be gifted to support.