• Title/Summary/Keyword: high isolation

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A Study on the Effective Half-life after the High Dose Radioactive Iodine (131I) Therapy for Thyroid Cancer Patients (갑상선암 환자에서 고용량 방사성요오드 치료 후 유효반감기에 대한 연구)

  • Kim, Seongcheol;Gwon, DaYeong;Kim, Yongmin
    • Journal of the Korean Society of Radiology
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    • v.11 no.7
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    • pp.597-603
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    • 2017
  • High-dose $^{131}I$ therapy has been generally carried out to remove remaining thyroid tissue or to cure metastasize lesion of patients who received full thyroidectomy due to differentiated thyroid cancers. In case high-dose $^{131}I$ therapy is carried out for a patient, the patient should be hospitalized being isolated for a certain period in order to restrict the amount of exposure to radiation of people at large from the patient within the limit of a level of radiation. Effective half-life is an important value to calculate how family members are exposed to radiation from a patient or to decide the period of isolation of the patient from the family members. Therefore, in this study we calculated the effective decay constant, effective half-life and period of isolation of high-dose $^{131}I$ therapy patient using NM670 SPECT/CT. As a result of carrying out this study, the effective half-life of high-dose $^{131}I$ therapy patients was derived and the time to reach the discharge level of 1.2 GBq was confirmed. When they were compared with each other in each of curative doses, the effective half-life did not have significant difference, but the time when the level of radiation remaining in the interior of the body to reach the criteria of isolation and discharge showed significant difference and it could be confirmed that the higher the curative dose the longer the period of isolation becomes. When the effective half-lives in each type of preparation were compared with each other, they did not show significant difference. However, When the times to reach the level of radiation that is the criteria of isolation and discharge in each type of preparations, they showed significant difference. The cause of the shortening of the isolation period for rhTSH patients group is decided to be low curative dose. Accordingly, if the current national health insurance (the insurance is applied to using of rhTSH in 3.7 GBq or lower) is maintained, while discerning them in each of types of preparation, we would be able to discharge patients at the time earlier than the current period of isolation (2 nights and 3 days).

Design of VHF-Band Wideband High-Power Switch (VHF 대역용 광대역 고전력 스위치 설계)

  • Lee, Byeong-Nam;Park, Dong-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.9
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    • pp.992-999
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    • 2008
  • This paper describes the design of SPST PIN diode switch which has a 2 kW high power handling capability within $50{\mu}s$ switching speed in $20{\sim}100$ MHz VHF-band. Design factors were investigated and it was confirmed by simulation that the characteristics of insertion loss, VSWR, and isolation met design goal. Also, the capability to handle 2 kW high power with maximum fast switching speed less than $20{\mu}s$ was confirmed and insertion loss less than 0.2 dB, VSWR less than 1.17:1, and isolation higher than 40 dB were obtained by experiments.

Design and fabrication of Diplexer for Dual-band GSM/DCS Application using High-Q Multilayer Inductors (고품질 적층형 인덕터를 이용한 이중 대역 GSM/DCS 대역 분리용 다이플렉서의 설계 및 제작)

  • Sim, Sung-Hun;Kang, Chong-Yun;Choi, Ji-Won;Yoon, Young-Joong;Yoon, Seok-Jin;Kim, Hyun-Jai
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2003.11a
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    • pp.294-298
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    • 2003
  • In this paper, the modeling and design of high-Q multilayer passives have been investigated, and multilayer diplexer for GSM/DCS applications has been designed and fabricated using the passives. To minimize the system, the configuration of a multilayer inductor has involved a square spiral structure. Modeling of a multilayer inductor was performed by the subsystems of distributed components, and using the modeling the optimal structures of the high-Q multilayer inductor could be designed by analyzing parasitics and couplings which affect their frequency characteristics. Multilayer diplexer for GSM/DCS application has been designed and fabricated using LTCC technology. LPF for GSM band had the passband insertion loss of less than 0.55 dB, the return loss of more than 12 dB, and the isolation level of more than 26 dB by locating attenuation pole at 1800 MHz. HPF for DCS band had the passband insertion loss of less than 0.82 dB, the return loss of more than 11 dB, and the isolation level of more than 38 dB by locating attenuation pole at 930 MHz.

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Fabrication and Characteristics of High-sensitivity Si Hall Sensors for High-temperature Applications (고온용 고감도 실리콘 홀 센서의 제작 및 특성)

  • 정귀상;노상수
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.565-568
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    • 2000
  • This paper describes on the temperature characteristics of a SDB(silicon-wafer direct bonding) SOI(silicon-on-insulator) Hall sensor. Using the buried oxide $SiO_2$ as a dielectrical isolation layer, a SDB SOI Hall sensor without pn junction isolation has been fabricated on the Si/$SiO_2$/Si structure. The Hall voltage and the sensitivity of the implemented SOI Hall sensor show good linearity with respect to the applied magnetic flux density and supplied current. In the temperature range of 25 to $300^{\circ}C$, the shifts of TCO(temperature coefficient of the offset voltage) and TCS(temperature coefficient of the product sensitivity) are less than $\pm 6.7$$\times$$10^{-3}$/$^{\circ}C$ and $\pm 8.2$$\times$$10^{-4}$/$^{\circ}C$respectively. These results indicate that the SDB SOI structure has potential for the development of a silicon Hall sensor with a high-sensitivity and hip high-temperature operation.

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Assessing the effect of inherent nonlinearities in the analysis and design of a low-rise base isolated steel building

  • Varnavaa, Varnavas;Komodromos, Petros
    • Earthquakes and Structures
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    • v.5 no.5
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    • pp.499-526
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    • 2013
  • Seismic isolation is an effective method for the protection of buildings and their contents during strong earthquakes. This research work aims to assess the appropriateness of the linear and nonlinear models that can be used in the analysis of typical low-rise base isolated steel buildings, taking into account the inherent nonlinearities of the isolation system as well as the potential nonlinearities of the superstructure in case of strong ground motions. The accuracy of the linearization of the isolator properties according to Eurocode 8 is evaluated comparatively with the corresponding response that can be obtained through the nonlinear hysteretic Bouc-Wen constitutive model. The suitability of the linearized model in the determination of the size of the required seismic gap is assessed, under various earthquake intensities, considering relevant methods that are provided by building codes. Furthermore, the validity of the common assumption of elastic behavior for the superstructure is explored and the alteration of the structural response due to the inelastic deformations of the superstructure as a consequence of potential collision to the restraining moat wall is studied. The usage of a nonlinear model for the isolation system is found to be necessary in order to achieve a sufficiently accurate assessment of the structural response and a reliable estimation of the required width of the provided seismic gap. Moreover, the simulations reveal that the superstructure's inelasticity should be taken into account, especially if the response of the structure under high magnitude earthquakes is investigated. The consideration of the inelasticity of the superstructure is also recommended in studies of structural collision of seismically isolated structures to the surrounding moat wall, since it affects the response.

A Study on Isolation Improvement of LTE-PIFA Used Stub Structure on Ground Plane (접지면 위의 스터브를 이용한 LTE-PIFA의 격리도 개선 연구)

  • Park, Chan-Jin;Min, Kyoeng-Sik
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.4
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    • pp.374-383
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    • 2013
  • This paper presents a design for improvement of isolation characteristics by the inserted stub structure on ground plane of a handy terminal which is composed of a main antenna and a sub antenna covered LTE bandwidth. In order to compensate for a resonance length of proposed antenna and to realize a high isolation characteristic, a pair of stub was inserted and located on ground plane that currents from two antennas were converged. A simulated isolation characteristic of antenna without stub at the LTE class 13 band was about -5 dB, but its characteristics of proposed antenna with two stubs at uplink(777~787 MHz) and downlink(746~756 MHz) of the LTE class 13 band were about -12 dB and -15 dB, respectively. An average gain of a fabricated antenna with two stubs was observed about -2 dBi above and it showed good results with comparison of business condition that the average gain of commercial handy terminal has to appear -4 dBi above. The measured S-parameter characteristics and radiation patterns showed a reasonable agreement with the simulation results.

Stability Evaluation of Phased Isolation Intra-Clarifier Ditch Process on Short-Term Hydraulic Shock Loading (단기 수리학적 충격부하시 침전지 내장형 상분리 산화구공정의 처리 안정성 평가)

  • Hong, Ki-Ho;Chang, Duk
    • Journal of Korean Society of Water and Wastewater
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    • v.19 no.6
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    • pp.791-799
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    • 2005
  • The phased isolation intra-clarifier ditch system used in this study is a simplified novel process enhancing simultaneous removal of biological nitrogen and phosphorus in municipal wastewater in terms of elimination of additional pre-anaerobic reactor, external clarifier, recycle of sludge, and nitrified effluent recirculation by employing intrachannel clarifier. Laboratory-scale phased isolation ditch system was used to assess the treatability on municipal wastewater. When the system was operated at the HRTs of 6~12hours, SRTs of 9~31days, and cycle times of 2~8hours, the system showed removals of BOD, TN, and TP as high as 88~97%, 70~84%, and 65~90%, respectively. The rainfall in Korea is generally concentrated in summer because of site-specific characteristics. Especially, the wet season has set in on June to August. In combined sewers, seasonal variations are primarily a function of the amount of stormwater that enters the system. In order to investigate the effect of hydraulic shock loading on system performance, the laboratory-scale system was operated at an HRT of 6hours (two times of influent flowrate) during two cycles (8hours). The system performance slightly decreased by increasing of influent flowrate and decreasing of system HRT. Nitrification efficiency and TN removal were slightly decreased by increasing of influent flowrate (decreasing of system HRT), whereas, the denitrification was not affected by hydraulic shock loading. However, the higher system performance could be achieved again after four cycles. Thus, the phased isolation technology for enhanced biological nutrient removal in medium- and small-scale wastewater treatment plants suffering fluctuation of influent quality and flowrate.

Design of a Metamaterial Absorber for High Isolation of a WCDMA Indoor Repeater Antenna (WCDMA 댁내형 중계기 안테나의 격리도 개선을 위한 메타 구조 기반의 흡수체 설계)

  • Yoon, Na-Nae;Kim, Hyoung-Jun;Seo, Chul-Hun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.9
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    • pp.1058-1064
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    • 2012
  • In this paper, an absorber based on metamaterial is proposed to improve the isolation of conventional WCDMA indoor repeater antenna. The proposed absorber is composed of Double Split Ring Resonators(DSRRs) and Complementary Spiral(CS) structure. The proposed absorber based on metamaterial is $9.6mm{\times}9.6mm{\times}1.2mm$ and absorption is about 94 % at 2.2875 GHz. The proposed antenna, which proposed absorber is applied to conventional WCDMA indoor repeater antenna, has isolation over 85 dB. Isolation is improved more than 10 dB compared with the conventional antenna. The VSWR is lower than 2 at WCDMA band from 1.92 GHz to 2.17 GHz. The radiation patterns are $60^{\circ}{\pm}10^{\circ}$ E-plane and H-plane, respectively. And, the gain is more than 6 dBi. The volume of proposed antenna with absorber based on metamaterial is $90mm{\times}90mm{\times}44.8mm$.

Development of AI and IoT-based smart farm pest prediction system: Research on application of YOLOv5 and Isolation Forest models (AI 및 IoT 기반 스마트팜 병충해 예측시스템 개발: YOLOv5 및 Isolation Forest 모델 적용 연구)

  • Mi-Kyoung Park;Hyun Sim
    • The Journal of the Korea institute of electronic communication sciences
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    • v.19 no.4
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    • pp.771-780
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    • 2024
  • In this study, we implemented a real-time pest detection and prediction system for a strawberry farm using a computer vision model based on the YOLOv5 architecture and an Isolation Forest Classifier. The model performance evaluation showed that the YOLOv5 model achieved a mean average precision (mAP 0.5) of 78.7%, an accuracy of 92.8%, a recall of 90.0%, and an F1-score of 76%, indicating high predictive performance. This system was designed to be applicable not only to strawberry farms but also to other crops and various environments. Based on data collected from a tomato farm, a new AI model was trained, resulting in a prediction accuracy of over 85% for major diseases such as late blight and yellow leaf curl virus. Compared to the previous model, this represented an improvement of more than 10% in prediction accuracy.

Drive Circuit of 4-Level Inverter for 42V Power System

  • Park, Yong-Won;Sul, Seung-Ki
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.11B no.3
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    • pp.112-118
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    • 2001
  • In the near future, the voltage of power system for passenger vehicle will be changed to 42V from existing 14V./ Because of increasing power and voltage ratings used in the vehicle the motor drive system has high switching dv/dt and it generates electromagnetic interference (EMI) To solve these problems multi-level inverter system may be used The feature of multi-level inverter is the output voltage to be synthesized from several levels of voltage Because of this feature high switching dv/dt and EMI can be reduced in the multi-level inverter system But as the number of level is increased manufacturing cost is getting expensive and system size is getting large. Because of these disadvantages the application of multi-level inverter has been restricted only to high power drives. The method to reduce manufacturing cost and system size is to integrate circuit of multi-level inverter into a few chips But isolated power supply and signal isolation circuit using transformer or opto-coupler for drive circuit are obstacles to implement the integrated circuit (IC) In this paper a drive circuit of 4-level inverter suitable for integration to hybrid or one chip is proposed In the proposed drive circuit DC link voltage is used directly as the power source of each gate drive circuit NPN transistors and PNP transistors are used to isolate to transfer the control signals. So the proposed drive circuit needs no transformers and opto-couplers for electrical isolation of drive circuit and is constructed only using components to be implemented on a silicon wafer With th e proposed drive circuit 4- level inverter system will be possible to be implemented through integrated circuit technology Using the proposed drive circuit 4- level inverter system is constructed and the validity and characteristics of the proposed drive circuit are proved through the experiments.