• 환경생물
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• 제39권2호
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• pp.218-224
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• 2021

본 연구에서는 열대우림인 브루나이 MDF와 PSF의 주요 수종(D. aromatic, D. rappa, C. arborescens)을 대상으로 초기 분해 단계의 수종별 질량 감소율과 탄질율의 변화를 파악하였다. 2019년 5월에 총 48개의 고사목 시료(15 cm ×4.8 cm ×5 cm)를 산림 지표면에 배치하고 16개월 후 수거하였다. 분해 전 수종별 고사목의 밀도(g cm^-3)는 0.64±0.01 (D. aromatic), 0.60±0.00 (D. rappa), 0.44±0.02 (C. arborescens) 등이었으며, 16개월 동안 수종별 연간 질량 감소율(%)은 6.37 (D. aromatic), 8.17 (D. rappa), 18.53 (C. arborescens) 등으로 나타났다. 부후등급은 C. arborescens에서 III등급이 약 25%로 높았으며 흰개미의 분해 흔적이 나타났다. 한편, 16개월 후 탄질율은 D. aromatic과 D. rappa에서 통계적으로 유의하게 감소하였으나, C. arborescens에서는 감소하는 경향이 유의하지 않았다. 이러한 연구 결과는 열대우림 내 고사목의 초기 분해는 밀도와 같은 수종의 물리적 특성에 따라 차이가 나타날 수 있으며, 주요 분해자의 유형에 따라 탄질율의 변화에도 상대적으로 차이가 있을 수 있음을 시사하는 것이다.

• 한국의학물리학회지:의학물리
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• 제33권4호
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• pp.129-135
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• 2022

Purpose: A full-energy-peak (FEP) efficiency correction is required through a Monte Carlo simulation for accurate radioactivity measurement, considering the geometrical characteristics of the detector and the sample. However, a relative deviation (RD) occurs between the measurement and calculation efficiencies when modeling using the data provided by the manufacturers due to the randomly generated dead layer. This study aims to optimize the structure of the detector by determining the dead layer thickness based on Monte Carlo simulation. Methods: The high-purity germanium (HPGe) detector used in this study was a coaxial p-type GC2518 model, and a certified reference material (CRM) was used to measure the FEP efficiency. Using the MC N-Particle Transport Code (MCNP) code, the FEP efficiency was calculated by increasing the thickness of the outer and inner dead layer in proportion to the thickness of the electrode. Results: As the thickness of the outer and inner dead layer increased by 0.1 mm and 0.1 ㎛, the efficiency difference decreased by 2.43% on average up to 1.0 mm and 1.0 ㎛ and increased by 1.86% thereafter. Therefore, the structure of the detector was optimized by determining 1.0 mm and 1.0 ㎛ as thickness of the dead layer. Conclusions: The effect of the dead layer on the FEP efficiency was evaluated, and an excellent agreement between the measured and calculated efficiencies was confirmed with RDs of less than 4%. It suggests that the optimized HPGe detector can be used to measure the accurate radioactivity using in dismantling and disposing medical linear accelerators.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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• pp.287-290
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• 1990

The paper describes the correction of the switching dead times avoiding a bridge leg short circuit in pulse width modulated voltage sorce inverters. The co consequences on AC variable speed drives with synchronous and asynchronous motors are described by harmonic analysis and by computer simulation.

• 대한수의사회지
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• 제18권1호
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• pp.41-44
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• 1982

1. The result that the author has been giving treatment for penguins for 5 years from April in 1976 upfill June of 1981 on young Farm L-and, three cases among eight cases of dead penguins were dead from Aspergillosis. 2. After aspergillus fumigutus isolat

• 한국잡초학회지
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• 제18권3호
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• pp.191-196
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• 1998

벼 무경운재배시 수확 잔재인 볏짚과 비선택성 제초제 처리로 고사한 둑새풀이 논토양을 피복할 때 이들이 잡초 발아 및 벼의 입모와 초기생육에 미치는 영향을 알기 위하여 1998년 Pot실험한 결과를 요약하면 다음과 같다. 1. 볏짚 + 둑새풀 피복구의 입모율은 56.9%로서 볏짚피복구의 79.2%, 무피복구의 80.6%에 비하여 유의하게 낮았다. 2. 볏짚 및 볏짚+둑새풀 고사체 피복은 무경운 직파벼의 초기분얼을 현저히 억제하였다. 그러나 분얼성기 이후에는 생육을 유의하게 증진시켰다. 3. 볏짚단독피복, 볏짚+둑새풀 고사체 피복은 무경운직파재배에서의 잡초발생을 유의하게 감소시켰다. 피의 방제가는 볏짚피복구가 98.5%, 볏짚+둑새풀 고사체피복구에서는 76.1%이었다. 4. 볏짚피복과 볏짚 + 둑새풀 고사체 피복은 담수 후 20일간 수중 pH와 용존산소량을 유의하게 낮추었다. 5. 볏짚 및 볏짚+둑새풀 고사체 피복은 무경운 직파구의 지온을 직파 5일간은 $1^{\circ}C$ 낮추었다가 9일 이후에는 오히려 $1^{\circ}C$ 정도 높였다.

• 한국환경농학회지
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• 제36권4호
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• pp.269-278
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• 2017

BACKGROUND: The objective of this study was to evaluate screening method of residual multi pesticides in dead birds by Orbitrap high resolution mass spectrometry (HRMS) to identify the cause of death for birds. METHODS AND RESULTS: Extraction and clean-up method of residual pesticides in liver of dead birds was used QuEChERS (Quick Easy Cheap Effective Rugged and Safe) and method validations was conducted using liquid chromatography and gas chroamtography with triple-quadrupole mass spectrometer (LC/MS/MS and GC/MS/MS) Also, we were evaluated screening method for the determination of residual pesticides in liver of dead birds by LC and GC Orbitrap Mass Spectrometry. Results of method validations, Correlation coefficients of the matrix matched calibration curves were >0.978, and the method detection limits (MDLs) and limits of quantitation (LOQ) were 2.8~72.1 ng/g (18.4 ng/g on average) and 9.0~230 ng/g (58.5 ng/g on average). The accuracy ranged from 69.1%to 130% (103% on average), and the precision values were less than 14.8%(3.8%on average). The screening of residual pesticides in liver of dead birds by LC and GC Orbitrap HRMS was detected monocrotophos, carbofuran, carbosulfan, deltametrin, benfuracarb, carbofuran, phosphamidon, prochloraz in investigated samples. CONCLUSION: This results showed that accurate mass were extraction of residual pesticides in dead birds by Orbitrap HRMS. It suggested that this screening method is applicable to the residual pesticide analysis for the cause of death as a main tool.

• 한국방사선학회논문지
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• 제12권7호
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• pp.801-806
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• 2018

게르마늄 결정은 검출에 유용하지 않지만, 광자를 강하게 약화하기 때문에 효율성 저하를 일어키는 불감층을 가지고 있다. 따라서 제조업체가 제공하는 데이터를 검출기 시뮬레이션 모델에 사용하면 계산된 효율성과 측정된 효율성 사이에 약간의 큰 차이가 나타난다. 고순도 게르마늄(HPGe) 검출기의 모양과 치수는 CT 스캔을 통해 몬테카롤롤 시뮬레이션을 위해 형상을 정확하게 형상화하였다. 이 결과 불감층 두께 증가가 효율 감소과정에 미치는 영향을 연구하고자 한다. 불감층의 조정은 50 - 1500 keV의 에너지 범위에서 측정 효율과 시뮬레이션 효율 사이의 ${\pm}3%$의 상대편차와 함께 좋은 일치임을 확인하였다. 불감층 두께에 변화를 주어 시뮬레이션 데이터를 비교하였다. 몬테카롤로 시뮬레이션 결과를 실험 결과와 비교하여 새로운 불감층 두꼐를 얻었다. 1.4와 1.6 mm 두께의 End Cap 시뮬레이션 모델에서 1.5mm 두께의 End Cap시뮬레이션 모델에 대한 불감층 두꼐 결과의 차이는 End Cap 치수의 정확성으로 인한 체계적인 오류였다. 통계적 오류와 체계적 오류를 고려한 후, 검출기의 불감충 두께는 $1.02{\pm}0.14mm$로 도출되었다. 따라서 불감층 두께의 증가는 효율성 감소에 영향을 미치는 것을 확인하였다.

• 제어로봇시스템학회논문지
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• 제11권9호
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• pp.741-749
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• 2005

This paper presents a nonlinear controller design for optical disk drive systems to improve anti-shock performance. The nonlinear anti-shock controller is added parallel to the original linear servo control loop. In the previous work, a dead-zone nonlinear element is used for the nonlinear controller and a PID control method is used for the linear controller. Although this parallel structure of the controller improves anti-shock performance, it has a narrow stability bound. In this paper, the dead-zone with saturation nonlinear element is proposed for the nonlinear controller. Since this nonlinear element improves stability margin, we can use higher slope gain of dead-zone than that of nonlinear controller using dead-zone only. In the linear controller design, it is shown that the lead-lag control has an improved stability margin over PID control. Numerical simulation results and experimental results show that the proposed method can get better performance to the external shock than previously proposed methods.

• Structural Engineering and Mechanics
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• 제48권4호
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• pp.467-477
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• 2013

Municipalities in the United Arab Emirates approve reinforced concrete design of building structures to follow either the ACI 318 or the BS 8110 code. Since the requirements of these codes are different from each, there is a need to compare the structural demand in the two codes. The main objective of this study is to compare the design requirements of the ACI 318 code with the BS 8110 code for the flexural, shear and axial compression limit states. The load factors and load combinations in the two codes are also compared. To do so, a large number of cross-sections with different geometries, material properties, and reinforcement ratios are analyzed following the procedures in the two codes. The relevant factored load combinations in the two codes are also investigated for a wide range of live-to-dead load ratios and for various wind-to-dead load ratios. The study showed that the differences between the design capacities in the ACI 318 and BS 8110 codes are minor for flexure, moderate for axial compression, and major for shear. Furthermore, the factored load combinations for dead load, live load and wind in the two codes yield minor-to-moderate differences, depending on the live-to-dead load ratio and intensity of wind.

• 한국잠사곤충학회지
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• 제39권2호
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• pp.146-153
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• 1997

The microsporidian infection with Nosema bombycis, reconfirmed its high virulence and transovarial tranmissibility, however, the characteristic symptom of the spots like pepper grains on the diseased larval skin was no more recognized by present varieties of the silkworm. Transovarial transmission rate detected from moth was above 90% in dead eggs or dead larvae in the rearing by mulberry leaves, 80% in the newly hatched larvae starved to death. Transovarially transmitted N. bombycis was easily observed from dead eggs and larvae, and were suggested an individual inspection of a few of dead eggs for detection of the pathogenic spores. The progeny population provided indicative factors on the sampling of predictive and corrective inspection. The higher concentration of N. bombycis spores included in the hindabdormal part of infected moth, applicative on the simple method of indivisual moth inspection. For the predictive inspection of growned 5th-instar larvae, N. bombycis infection was detectable without microscopic observation by the unique symptom of turbid milky-white spots on the silk gland. Inspection of the meconia artificially discharged from silkworm moth, was also succesful of microscopic observation before crossing, without killing or homogenize the moths. The results provided a basis of rational methods for the inspection of N. bombycis infection of the silkworm.