• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.1
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• pp.124-132
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• 1998

The Korean-made passive samplers were evaluated at the working environment for field testing. Tested materials were n-hexane, toluene and trichloroethylene. The performance of passive samplers depended on types and concentrations of organic vapors. Sampling rates were not steady until certain concentrations. The optimum concentration for determination of airborne toluene by passive samplers was equal to or over 10 ppm which is 1/10 of the Korean occupational exposure limit. Optimum concentration of n-hexane was equal to and over 1 ppm which is 1/50 of Korean occupational exposure limit. But for trichloroehtylene, coefficient of variation was 53.5 %. Passive samplers may be used for determination of n-hexane. For other materials, further study on the performance of Korean-made passive samplers is required.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.6
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• pp.904-911
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• 2006

Passive sampler is simple and inexpensive measuring equipment for air pollution. In this study we developed colorimetric ozone passive sampler which was coated a colorimetric reagent to a filter substrate. Interference of criteria all pollutant ($SO_2,\;NO_2,\;CO$) on ozone passive sampler was investigated through experimental chamber. Field measurement of developed ozone passive samper was compared automatic sampler result in Suwon area. The results shows interference of $SO_2$ gas is larger than other gases. Developed passive sampler can be roughly applicable to wind speed range from 0.8 to 3.3 m/s, temperature range from 3.9 to $27.5^{\circ}C$ and relative humidity range from 48 to 84%.

• Hwankyungkyoyuk
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• v.11 no.2
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• pp.252-261
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• 1998

Since 1980's during which environmental pollution became serious enough to urge various types of environmental educations in many areas. But, most emphasis has been put on theoretical education. Even field education training mostly focused on water pollution. Therefore, simple air pollution monitoring system was needed for better field education in air pollution. In this study, we evaluated Passive Sampler as an useful tool for teaching air pollution in field. Students have found passive sampler very effective tool. Recent comparative study of auto-monitoring and passive sampler networks suggested a potential use of passive sampler as an useful tool for environmental education. In this study, the correlation between two sets of values appears very high judging from the regression slope of 0.92 and correlation coefficient of 0.91 However, inexpensive Passive sampler with easy-to-operate colorimeter, has not been used in environmental education partially because large scale fluctuation in time and space characteristic to air pollution has been overlooked so that the sampler has not been tested for an effective educational tool. Passive sampler certainly deserves further in depth research as an effective air monitoring system, and better attention to its usefulness to teach students and public.

• Smart Structures and Systems
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• v.15 no.3
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• pp.831-846
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• 2015

Magneto-Rheological (MR) dampers are being used increasingly because of their adaptability to control algorithms and reliability of passive systems. In this paper, an extensive investigation on performance of MR dampers in semi-active and passive modes has been carried out. It is observed that the overall energy dissipation by MR dampers in passive-on modes is higher than that in semi-active modes for most of the competitive semi-active controllers. Based on the energy dissipation pattern, a novel semi-active controller, termed as "Simple Passive Semi-Active Controller", has been proposed for MR dampers. This controller can be emulated by a simple passive hardware proposed in this paper. The proposed concept of controller "hardware emulation" is innovative and can also be implemented for other semi-active devices for control algorithms of certain form. The effectiveness and reliability of the proposed controller has been investigated extensively through numerical simulations. It has been demonstrated that the proposed controller is competitive to or more effective than other widely used / investigated semi-active controllers.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.5
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• pp.1365-1377
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• 2016

The purpose of this study is to find out by comparing the ability of comprehension and production of causative and passive sentences and grammatical morphemes between multicultural family children and normal children. Fifteen multicultural family children and fifteen normal children aged 7-9 years participated in this study. The results of this study are as follows; First, the children of multicultural family showed significantly a lower ability to comprehension and production of causative and passive sentences compared to normal children. Second, the children of multicultural family showed the difference about the acquisition of grammatical morpheme of causative and passive compared to normal children. Third, multicultural family children and normal children were not statistically significant differences in comprehension and production abilities of causative and passive in accordance with the increase of age.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.757-760
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• 1999

Depending upon the existence of the battery, transponder is divided into active and passive transponder. The passive transponder operates without battery and so has no limitation in its operating range and life time. But it needs the RF-DC conversion circuit. In this paper, the analysis and design of the RF-DC conversion circuit in passive transponder operated in high frequency is presented and is confirmed by simulation and experiment.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.1951-1953
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• 1998

In this study, we present the power conversion system of the passive transponder which is operated at 2.4GHz. First, The passive transponder which is the power conversion system is one of the passive transponder elements is presented. And then the power conversion system is analyzed and simulated.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.199-202
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• 2002

This paper is about the implementation of Passive RFID(Radio Frequency Identification) tag system using a capacitive method, and explains the design and circuit's structure of this system. Fundamentally the capacitive RFID tag system consists of a tag reader, a passive tag and a host computer. And then this paper shows the system's prototype which analyzes a specification, and suggests the passive RFID system as a new method which manufactures a low cost tag system easily

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.175-177
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• 2007

An analysis on a passive current sharing characteristics of a multi-phase synchronous buck converter is presented. The passive current sharing method is simple but its characteristics depend on the converter equivalent resistance and PWM uniformity. In this paper, the load sharing and power consumption of the passive current sharing system for the converter equivalent resistance and duty ratio inequalities are investigated through the simulation and experiment.

• The korean journal of orthodontics
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• v.26 no.6
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• pp.717-721
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• 1996

With conventional orthodontics, it was difficult for the anchorage segments of the wire to be engaged passively in the brackets even with complicated bending. To overcome this limitation, a kind of indirect bonding, "passive bracketing", has been developed. The present article shows laboratory and clinical procedures of the passive bracketing