• Geomechanics and Engineering
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• 제32권6호
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• pp.601-613
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• 2023

Low liquid limit silt, widely distributed in the middle and down reaches of Yellow River, has the disadvantages of poor grading, less clay content and poor colloidal activity. It is very easy to cause vehicle jumping at the bridge-embankment transition section when the low liquid limit silt used as the backfill at the abutment back. In this paper, a series of laboratory tests were carried out to study the physical and mechanical properties of the low liquid limit silt used as back filling. Ground granulated blast furnace slag (GGBFS) was excited by active MgO and hydrated lime to solidify silt as abutment backfill. The optimum ratio of firming agent and the compaction and mechanical properties of reinforced soil were revealed through compaction test and unconfined compressive strength (UCS) test. Scanning electron microscope (SEM) test was used to study the pore characteristics and hydration products of reinforced soil. 6% hydrated lime and alkali activated slag were used to solidify silt and fill the model of subgrade respectively. The pavement settlement regulation and soil internal stress-strain regulation of subgrade with different materials under uniformly distributed load were studied by model experiment. The effect of alkali activated slag curing agent on curing silt was verified. The research results can provide technical support for highway construction in silt area of the Yellow River alluvial plain.

• Biomolecules & Therapeutics
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• 제20권2호
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• pp.234-238
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• 2012

Propofol is an anesthetic commonly used to provide sedation or to induce and maintain an anesthetic stated. However, there are reports which indicate propofol may cause psychological dependence or be abused. In the present study, we used various behavioral tests including climbing test, jumping test, conditioned place preference, and self-administration test to assess the dependence potential and abuse liability of propofol compared to a positive control (methamphetamine) or a negative control (saline or intralipid). Among the tests, the conditioned place preference test was conducted with a biased method, and the selfadministration test was performed under a fixed ratio (FR) 1 schedule, 1 h per session. No difference was found in the climbing test and jumping test, but propofol (30 mg/kg, i.p.) increased the rewarding effect in the conditioned place preference test, and it showed a positive reinforcing effect compared to the vehicle. These results indicate that propofol tends to show psychological dependence rather than physical dependence, and it seems not to be related with dopaminergic system.

• International Journal of Aeronautical and Space Sciences
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• 제12권1호
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• pp.37-42
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• 2011

An extended scalar adaptive filter for guided missiles using a global positioning system receiver is presented. A conventional scalar adaptive filter is adequate filter for eliminating sudden abnormal jumping measurements. However, if missile or vehicle velocities have variation, the conventional filter cannot eliminate abnormal measurements. The proposed filter utilizes an acceleration term, which is an improvement not used in previous conventional scalar adaptive filters. The proposed filter continuously estimates noise measurement variance, velocity error variance and acceleration error variance. For estimating the three variances, an innovation method was used in combination with the least square method for the three variances. Results from the simulations indicated that the proposed filter exhibited better position accuracy than the conventional scalar adaptive filter.

• 한국안전학회지
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• 제10권4호
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• pp.13-21
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• 1995

On mini-bus with diesel engine, at idle rpm for taking measurement to reduce gear rattle noise, was tested by the three clutch disc samples by turns, then measured the fluctuation of revolution of engine & transmission and parallel vibration of differential gear & transmission. By analyzing the measured data, the gear rattle noise, the matching design and tuning technic of transmission are comprehended and established. Conclusions of this test are as follows ; (1) Fluctuation of revolution on transmission is greatly affected by torsion of clutch disc according to fluctuation of engine revolution transmit to transmission through clutch system. Especially, gear rattle noise can be reduced by minimaizing the fluctuation of the revolution of transmission using pre-damper type clutch disc. (2) The reason of gear rattle noise is higher in summer than winter and driving longer period than initial driving is due to affection by drag torque changing. So, it is necessary for manufacturer to choose proper oil to transmission. (3) It can be occurred jumping and crash noise by applying the pre-damper type clutch disc for reducing the gear rattle noise. So, it is necessary to do test with actual vehicle according to test procedure.

• 환경영향평가
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• 제27권2호
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• pp.232-239
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• 2018

이 연구는 국내 로드킬(Roadkill) 피해 발생건수가 가장 높은 야생동물인 고라니(Hydropotes inermis)를 대상으로 로드킬 예방에 필요한 저감시설인 유도울타리의 적정 높이 기준을 마련하기 위해 이루어졌다. 이를 위해 국외 사슴류 흰꼬리사슴(Odocoileus virginianus)의 울타리 월장 측정 연구사례와 비화학적 포획 방법을 검토하여 국립생태원 사슴생태원에서 관리하는 고라니 27마리를 대상으로 울타리 월장 실패율 측정 방법에 적용하였다. 펜스(test fence) 높이 0.5m에서부터 단계별 10cm씩 높여가며 넘을 수 없는 높이를 검증하였다. 그 결과 1.5m로 설치할 경우 고라니의 침입을 96.7% 차단 가능하고, 1.8m 높이에서는 100% 차단하는 것으로 확인되었다. 이 연구결과를 토대로 향후 환경부 "생태통로 설치 및 관리지침" 개정 시 유도울타리 적정 높이 기준 설정에 의미 있는 자료로 활용될 것으로 기대된다.