• Title/Summary/Keyword: frequency standard

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Electrochemical Approach in Plasma Display Panel Glass Melts doped with Sulfate and Sulfide II. Square Wave Voltammetry

  • Kim, Ki-Dong
    • Journal of the Korean Ceramic Society
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    • v.45 no.7
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    • pp.375-379
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    • 2008
  • Redox behavior was observed in alkali alkaline earth silicate PDP (Plasma Display Panel) glass melts doped with sulfate and sulfide by square wave voltammetry (SWV). According to voltammograms produced at a temperature range of 1100 to $1400^{\circ}C$ and frequency range of 5 to 1000 Hz, both melts showed the same behavior in which there is one reduction peak at low frequency but another peak at an increase of frequency. Based on the frequency dependence of the peak current, self diffusivity of $S^{4+}$ was determined. Based on the temperature dependence of the peak potential, standard enthalpy (${\Delta}H^0$) and standard entropy (${\Delta}S^0$) for the reduction of $S^{4+}$ to $S^0$ were calculated.

Modal Parameter Estimation of Membrane for Standard Microphone Sensitivity Calibration (표준 마이크로폰 감도 교정을 위한 진동막의 모달 파라미터 측정)

  • 권휴상;서상준;서재갑;박준홍
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.298-302
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    • 2002
  • Equivalent volume estimation of the coupler and two coupled microphones has a key role in standard microphone pressure calibration. The equivalent volume of the microphone is determined by the dynamic characteristics of the diaphragm system and front cavity. Therefore the modal parameters of diaphragm system - natural frequency and damping fatter - should be measured explicitly for the estimation of the equivalent volume. The diaphragm system is composed of the vibrating diaphragm, back slit behind diaphragm, pressure equalization vent, and front cavity which are acoustically coupled. In the measurement, the electrostatic actuator was used to excite the system with the swept sine, and the frequency response was obtained. The close actuator in front of the diaphragm must influence the radiation impedance of the system, and then the modal parameters. From the measured frequency response, the natural frequency and the damping factor could be estimated with the Complex exponential method based on the Prony model and the zero crossing real and imaginary plot.

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Noise and Vibration Characteristics of Concrete Floor Structures Using Resilient Materials Driven by Standard Heavy Impact Source (완충재 유무에 따른 표준중량충격원에 의한 콘크리트 바닥 구조의 소음 및 진동 특성)

  • 송희수;전진용;서상호
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.8
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    • pp.661-667
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    • 2004
  • The characteristics of noise and vibration by a heavy impact source was studied. The triggering method was used for increasing the reliability and stability to measure the level of sound pressure. sound intensity and vibration acceleration. A simple finite element model and a rigid body analysis method were suggested to calculate the natural frequencies of the multi-layer floor system. The results show that the resilient materials decrease the natural frequency of the reinforced concrete slab, make a resonance with dominant driving frequency in the low frequency region, and increase the vibration and noise level. A simple finite element model and rigid body models was suggested to calculate the natural frequencies of the floor systems.

A Study on the Still Image Compression using the Low Pass Filter (로우 패스 필터를 이용한 정지 영상 압축에 관한 연구)

  • 김성종;신인철
    • Proceedings of the Korea Society for Industrial Systems Conference
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    • 1997.11a
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    • pp.91-101
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    • 1997
  • The demand for handling images in digital form has increased dramatically in recent years. Digital image compression is required to store and transmit mass information in different from general information. JPEG(Joint Photographic Experts Group) committee founded by CCITT and ISO is define the still-image standard compression/restoration algorithm. JPEG is proposed the standard of grayscale and color still-image compression/restoration. In the image quality, JPEG is applicable to the various applications in which compression is able to from 1/10 to 1/50 without the visible obstacle. In this paper, we proposed that the proposed method enhance the compression ratio which is reducing the higher frequency in order to increasing the spatial redundancy in the image. The proposed method is using the low pass filter in order to reducing the higher frequency. The low-pass filters are using the median filter and convolution filter in the spatial domain, FFT filter in the frequency domain. We acquired the additive compression ratio reducing the higher frequency using the low-pass filter.

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Study on Vibration Fatigue Analysis of Automotive Battery Supporter (자동차 배터리 지지 구조의 진동 피로 해석에 대한 연구)

  • Ah, Sang Ho
    • Journal of Auto-vehicle Safety Association
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    • v.11 no.4
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    • pp.22-27
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    • 2019
  • In this paper, the vibration load and analysis results for automotive battery supporter were performed to provide efficient vibration tolerance performance prediction methods for single-product vibration tolerance testing, and the major influencing factors and considerations for setting up single-unit vibration tolerance tests were reviewed. A common applicable standard load was applied to efficiently predict the performance of single-unit vibrations through the frequency response analysis technique. The results similar to test results can be predicted by checking vulnerable parts of the vehicle components for vibration loads and applying scale factor to standard loads. In addition, it was confirmed that the test conditions with a frequency generating the same durability severity as the endurance test are needed for accurate prediction of the durability of the single-unit vibration tolerance test conditions, and the acceleration and frequency with the conditions that there is no significant nonlinear phenomena in the vibration system are established during the single-unit vibration tolerance test conditions.

Analysis of Standard Nursing Statements Recorded in an Electronic Nursing Record System and User Satisfaction (전자간호기록에 사용된 표준간호진술문 활용실태와 시스템 사용자 만족도)

  • Jung, Joo Hee;Myung, Geun Hee;Kang, Kyung Hyun;Park, Eun Hee
    • Perspectives in Nursing Science
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    • v.9 no.2
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    • pp.146-153
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    • 2012
  • Purpose: The aims of this study were to analyze the frequency of standard nursing statements used in the Electronic Nursing Record (ENR) and to evaluate the degree of satisfaction by users of the ENR system. Methods: We retrospectively reviewed the ENR of 1914 patients who were admitted to our center between 1 May 2011 and 31 May 2011. Additionally, we collected questionnaires from 100 doctors and 300 nurses to evaluate the satisfaction of the users. Results: The frequency of use for the following standard nursing statements was investigated: standard nursing assessment statements (43.6%), standard nursing diagnosis statements (61.8%), standard nursing plan statements (46.7%), standard nursing intervention statements (56.9%), and standard nursing evaluation statements (41.7%). The mean satisfaction score was 3.03 out of 5 in the nurse's group, and 3.11 in the doctor's group. The nurses said the advantages of the ENR system were as follows: easy to access, informative, and standardized terms. However 75.7% of the nurse answered that they cannot express actual nursing situations exactly with the currently limited standard nursing statements. Conclusion: Development of various standard nursing statements is needed to meet the demands of the users. As a result, the use of the ENR system would become easier and more efficient for its users.

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A CMOS Frequency divider for 2.4/5GHz WLAN Applications with a Simplified Structure

  • Yu, Q.;Liu, Y.;Yu, X.P.;Lim, W.M.;Yang, F.;Zhang, X.L.;Peng, Y.
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.11 no.4
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    • pp.329-335
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    • 2011
  • In this paper, a dual-band integer-N frequency divider is proposed for 2.4/5.2 GHz multi-standard wireless local area networks. It consists of a multi-modulus imbalance phase switching prescaler and two all-stage programmable counters. It is able to provide dual-band operation with high resolution while maintaining a low power consumption. This frequency divider is integrated with a 5 GHz VCO for multi-standard applications. Measurement results show that the VCO with frequency divider can work at 5.2 GHz with a total power consumption of 22 mW.

The Study on Standard Bodytype for Korean Women between the ages of 18 and 24 years old(Part I) -focusing on the analysis of the High-frequency type and the High-frequency range- (18~24세 한국인 여성의 표준체형에 관한 연구(제1보) -다빈도유형 및 다빈도구간에 대한 분석을 중심으로-)

  • 이정임;남윤자
    • Journal of the Korean Society of Clothing and Textiles
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    • v.26 no.5
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    • pp.630-641
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    • 2002
  • The purpose of this study is to suggest the standard of bodytype which offers various data with regard to three-dimensional characteristics of body, and which offers the criterion for the sizes and shapes to interpret various bodytypes, to estimate filling, and to construct ready-made clothing. In this study, standard bodytype was defined as a typical type with beautiful proportion and shape which a large number of people have, too. In order to continue this study, there were two ways of analyzing bodytypes of subjects in the view of statistics and beauty. We primarily carried on statistical analysis in this report. Taken as a sample, the subjects were ninety-seven females who were between the ages of 18 and 24 years o1d. They were measured on November 1999. The data of seven hundred and few females, 18∼24 year-old, from the National Somatometry Survey of 1997 were used for analysis, too. Three kinds of classification methods were used for statistical analysis. The first method was based on the lateral view of the body, the second was based on the Factor and Cluster analysis of the photographic measurements of each of the anterior and lateral body, and the third was based on the Factor and Cluster analysis of the anthropometric measurements of the whole body. From the analysis on the distribution of R hrer Index the difference of width, the difference of depth, the proportion of height and head height, the High-frequency Proportion(H.P.)range were selected. The straight type from the lateral view, High-frequency type from each method, and subjects in H.P. range were compared with each other. As the result, it was confirmed that it is proper to base on the size and shape of subjects in H.P. range to analyze the standard bodytype.

PERFORMANCE EVALUATION AND IMPLEMENTATION OF CLOCK SYSTEM FOR KOREAN VLBI NETWORK (한국우주전파관측망(KVN)을 위한 시각 시스템 구축과 성능측정)

  • Oh, Se-Jin;Je, Do-Heung;Lee, Chang-Hoon;Roh, Duk-Gyoo;Chung, Hyun-Soo;Byun, Do-Young;Kim, Kwang-Dong;Kim, Hyo-Ryung;Jung, Gu-Young;Ahn, Woo-Jin;Hwang, Jeong-Wook
    • Publications of The Korean Astronomical Society
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    • v.22 no.4
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    • pp.189-199
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    • 2007
  • In this paper, we describe the proposed KVN (Korean VLBI Network) clock system in order to make the observation of the VLBI effectively. In general, the GPS system is widely used for the time information in the single dish observation. In the case of VLBI observation, a very high precise frequency standard is needed to perform the observation in accordance with the observation frequency using the radio telescope with over 100km distance. The objective of the high precise clock system is to insert the time-tagging information to the observed data and to synchronize it with the same clock in overall equipments which used in station. The AHM (Active Hydrogen Maser) and clock system are basically used as a frequency standard equipments at VLBI station. This system is also adopted in KVN. The proposed KVN clock system at each station consists of the AHM, GPS time comparator, standard clock system, time distributor, and frequency standard distributor. The basic experiments were performed to check the AHM system specification and to verify the effectiveness of implemented KVN clock system. In this paper, we briefly introduce the KVN clock system configuration and experimental results.