• Title/Summary/Keyword: 1st Frequency

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United Electromagnetic Characteristics and Online Monitoring Method of Static Air-gap Eccentricity of Turbo-Generator

  • Tang, Gui-Ji;Ke, Meng-Qiang;He, Yu-Ling;Wang, Fa-Lin
    • Journal of Electrical Engineering and Technology
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    • v.11 no.6
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    • pp.1614-1627
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    • 2016
  • The purpose of this paper is to investigate the united Electromagnetic characteristics for the effective monitoring on the static air-gap eccentricity (SAGE) of turbo-generator. Different from other studies, this paper not only studies on the unbalanced magnetic pull (UMP) and the vibration characteristics of the stator and the rotor, but also investigates the harmonic features of the magnetic flux density and the circulating current inside the parallel branches (CCPB). The theoretical calculation, together with the finite-element-method (FEM) simulation and the experiment verification, is taken for a SDF-9 type non-salient generator. It is shown that, when SAGE occurs, apparent double-frequency UMP and vibrations will be produced both on the stator and the rotor, while the CCPB will have an obvious increment at the $1^{st}$ harmonic component. In addition, the amplitude of the magnetic flux density will be of cosine distribution in the circumferential position of the air-gap, while in normal condition it is a constant. Moreover, the pass-band amplitude, together with the $1^{st}$ harmonic of the magnetic flux density, will be enlarged as well. These united electromagnetic characteristics can be used as the diagnosis and monitoring criterion for SAGE.

PQ Control of Micro Grid Inverters with Axial Voltage Regulators

  • Chen, Yang;Zhao, Jinbin;Qu, Keqing;Li, Fen
    • Journal of Power Electronics
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    • v.15 no.6
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    • pp.1601-1608
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    • 2015
  • This paper presents a PQ control strategy for micro grid inverters with axial voltage regulators. The inverter works in the voltage-controlled mode and can help improve the terminal power quality. The inverter has two axial voltage regulators. The 1st regulator involves the output voltage amplitude and output impedance, while the 2nd regulator controls the output frequency. The inverter system is equivalent to a controllable voltage source with a controllable inner output impedance. The basic PQ control for micro grid inverters is easy to accomplish. The output active and reactive powers can be decoupled well by controlling the two axial voltages. The 1st axial voltage regulator controls the reactive power, while the 2nd regulator controls the active power. The paper analyses the axial voltage regulation mechanism, and evaluates the PQ decoupling effect mathematically. The effectiveness of the proposed control strategy is validated by simulation and experimental results.

Two Cases of Primary Splenic Hydatid Cyst in Greece

  • Vezakis, Antonios;Dellaportas, Dionysios;Polymeneas, George;Tasoulis, Marios Konstantinos;Chondrogiannis, Constantinos;Melemeni, Aikaterini;Polydorou, Andreas;Fragulidis, George Panagiotis
    • Parasites, Hosts and Diseases
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    • v.50 no.2
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    • pp.147-150
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    • 2012
  • Cystic disease of the spleen is an uncommon entity in general population. Most cases result from parasitic infection by Echinococcus granulosus, a form called splenic hydatid disease (SHD), with a reported frequency of 0.5-6.0% within abdominal hydatidosis. On the contrary, an isolated splenic involvement of hydatid disease is very uncommon even in endemic regions. Two cases of primary SHD managed with open and laparoscopic radical surgery in our department are reported herein. Primary SHD is a rare entity with non-specific symptoms underlying clinical suspicion by the physician for prompt diagnosis. Surgical treatment is the mainstay therapy, while laparoscopic approach when feasible is safe, offering the advantages of laparoscopic surgery.

Design of Menu Driven Interface using Error Analysis (에러 분석을 통한 사용자 중심의 메뉴 기반 인터페이스 설계)

  • Han, Sang-Yun;Myeong, No-Hae
    • Journal of the Ergonomics Society of Korea
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    • v.23 no.4
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    • pp.9-21
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    • 2004
  • As menu structure of household appliance is complicated, user's cognitive workload frequently occurs errors. In existing studies, errors didn't present that interpretation for cognitive factors and alternatives, but are only considered as statistical frequency. Therefore, error classification and analysis in tasks is inevitable in usability evaluation. This study classified human error throughout information process model and navigation behavior. Human error is defined as incorrect decision and behavior reducing performance. And navigation is defined as unrelated behavior with target item searching. We searched and analyzed human errors and its causes as a case study, using mobile phone which could control appliances in near future. In this study, semantic problems in menu structure were elicited by SAT. Scenarios were constructed by those. Error analysis tests were performed twice to search and analyze errors. In 1st prototype test, we searched errors occurred in process of each scenario. Menu structure was revised to be based on results of error analysis. Henceforth, 2nd Prototype test was performed to compare with 1st. Error analysis method could detect not only mistakes, problems occurred by semantic structure, but also slips by physical structure. These results can be applied to analyze cognitive causes of human errors and to solve their problems in menu structure of electronic products.

Phentermine and Phendimetrazine-Induced Psychotic Disorder and Bipolar Disorder: A Case Series (Phentermine 및 Phendimetrazine으로 유발된 정신병적 장애 및 양극성 장애 증례군 연구)

  • Kim, Soo Young;Kim, Tae-Suk;Kim, Dai-Jin;Chae, Jeong-Ho;Lee, Chang Uk;Joo, Soo Hyun
    • Korean Journal of Biological Psychiatry
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    • v.29 no.1
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    • pp.22-31
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    • 2022
  • Objectives Recently, weight loss has emerged as a national concern in South Korea, and this has resulted in an increase in the frequency of use of central nervous system (CNS)-stimulating appetite suppressants. This study aimed to collect cases of psychotic disorders and bipolar disorders triggered by phentermine and phendimetrazine and explore the clinical features and courses. Methods In this retrospective study, we analyzed the electronic medical records of patients and selected eight patients who developed psychotic symptoms and manic symptoms for the first time after taking phentermine and phendimetrazine. All cases were reviewed, and their clinical features and course were summarized. Results All eight patients developed psychotic symptoms, and one had accompanying manic symptoms. The final diagnosis was appetite-suppressant-induced psychotic disorder in four patients, schizophrenia in three, and appetite-suppressant-induced bipolar disorder in one. In addition, three patients were diagnosed as having substance-use disorder. The key psychotic symptoms of these patients were hallucinations and paranoia. Conclusions These case findings suggest that phentermine and phendimetrazine can cause psychotic disorder, bipolar disorder, or substance use disorder and that medical professionals and the public should practice caution when prescribing and using these drugs.

Numerical Analysis of Three Dimensional Supersonic Flow around Cavities

  • Woo Chel-Hun;Kim Jae-Soo;Kim Jong-Rok
    • 한국전산유체공학회:학술대회논문집
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    • 2006.05a
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    • pp.311-314
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    • 2006
  • The supersonic flow around tandem cavities was investigated by three- dimensional numerical simulations using the Reynolds-Averaged Navier-Stokes(RANS) equation with the $\kappa-\omega$ thrbulence model. The flow around a cavity is characterized as unsteady flow because of the formation and dissipation of vortices due to the interaction between the freestream shear layer and cavity internal flow, the generation of shock and expansion waves, and the acoustic effect transmitted from wake flow to upstream. The upwind TVD scheme based on the flux vector split using van Leer's limiter was used as the numerical method. Numerical calculations were performed by the parallel processing with time discretizations carried out by the 4th-order Runge-Kutta method. The aspect ratio of cavities are 3 for the first cavity and 1 for the second cavity. The ratio of cavity interval to depth is 1. The ratio of cavity width to depth is 1 in the case of three dimensional flow. The Mach number and the Reynolds number were 1.5 and $4.5{\times}10^5$, respectively. The characteristics of the dominant frequency between two-dimensional and three-dimensional flows were compared, and the characteristics of the second cavity flow due to the fire cavity flow cavity flow was analyzed. Both two dimensional and three dimensional flow oscillations were in the 'shear layer mode', which is based on the feedback mechanism of Rossiter's formula. However, three dimensional flow was much less turbulent than two dimensional flow, depending on whether it could inflow and outflow laterally. The dominant frequencies of the two dimensional flow and three dimensional flows coincided with Rossiter's 2nd mode frequency. The another dominant frequency of the three dimensional flow corresponded to Rossiter's 1st mode frequency.

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Benefits of Palliative Office-Based Hyaluronic Acid Injection Laryngoplasty in Cancer-Related Unilateral Vocal Cord Paralysis Patients (악성 종양 관련 일측성 성대 마비 환자에서 고식적 Hyaluronic Acid 성대 주입 성형술의 유용성)

  • Kim, Go-Woon;Park, Young-Hak;Joo, Young-Hoon;Kim, Sang-Yeon;Shim, Mi-Ran;Hwang, Yeon-Sin;Sun, Dong-Il
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.29 no.1
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    • pp.30-36
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    • 2018
  • Background and Objectives : The effect of palliative injection laryngoplasty in cancer-related unilateral vocal cord paralysis patients on voice and swallowing function is uncertain and there are few previous studies of its suitability, benefits as a palliative treatment option. The purpose of this study is to confirm the objective results of voice and swallowing function after palliative office-based hyaluronic acid injection laryngoplasty in cancer-related unilateral vocal cord paralysis patients. Materials and Method : 36 patients who had unilateral vocal cord paralysis from non-thyroidal, extralaryngeal neoplasms were included in this study. To evaluate the clinical outcome, we analyzed perceptual GRBAS grading, acoustic analysis, aerodynamic study, Electroglottography (EGG), Voice Handicap Index (VHI-30) about voice function and disability rating scale (DRS), gastric tube dependency, aspiration pneumonia about swallowing function and 36-Item Short Form Survey version 2 (SF-36v2) about quality of life. Results : In GRBAS scale, G (p<0.001), R (p=0.004), B (p=0.001), A (p=0.011), and S (p=0.007) showed significant improvement. Jitter, shimmer, speaking fundamental frequency, maximal phonation time, VHI-30, DRS score, gastric tube dependency, aspiration pneumonia, and SF-36v2 were significantly improved after injection (p=0.016, p=0.011, p=0.045, p=0.005, p<0.001, p<0.001 p=0.003, p<0.001, and p<0.001 respectively). Conclusion : From this study we concluded office-based hyaluronic acid injection can be used as a useful palliative treatment option in cancer-related ill patients with unilateral vocal cord paralysis. Palliative hyaluronic acid injection laryngoplasty avoids the need for tube feeding, thus reducing the risk of aspiration pneumonia. These outcomes are accompanied by significant improvement in voice quality.

Studies on electrocardiogram of the normal Korean native cattle I. Standard limb leads (정상적(正常的)인 한우(韓牛)의 심전도(心電圖)에 관(關)한 연구(硏究) I. 표준지유도(標準肢誘導))

  • Choi, In-hyuk;Jung, In-sung;Kim, Nam-soo;Suh, Doo-seok
    • Korean Journal of Veterinary Research
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    • v.33 no.4
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    • pp.719-734
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    • 1993
  • The electrocardiographic(ECG) parameters on the standard limb leads in the normal Korean native cattle have been measured with a 3 channel Electrocardiograph built in a computed analysis. The study was conducted on the animals 98 heads of mean age of 17.7 months. Conduction parameters, waves, intervals and segments have been recorded. The recordings were analyzed as to shape and amplitude of the P and T waves and the components of the QRS complex. Heart rate was recorded by the Electrocardiogram which were a mean of $80.4{\pm}11.6beats/min$. And the younger had a higher heart rate than the older one. Average conduction times in the RP, the QRS complex and the QTc interval recorded $166.7{\pm}23.1msec.$, $79.7{\pm}8.8msec.$ and $395.5{\pm}30.4msec.$, in the P and T wave duration recorded $70.1{\pm}13.5msec.$ and $97.6{\pm}16.9msec.$, and in the PR and ST segment duration recorded $97.9{\pm}23.5msec.$ and $173.9{\pm}40.3msec.$, respectively. The wave forms in each lead observed various types. The amplitudes of wave type showed the highest frequency in each lead that were analyzed as follow : 1. In P wave, amplitudes of the positive type showed the frequency of 65.3%, 82.7% and 52.0% in leads I, II and III that were $103.1{\pm}47.8{\mu}V$, $115.2{\pm}37.3{\mu}V$ and $67.4{\pm}26.9{\mu}V$, and it showed the frequency of 54.1% and 85.7% in the leads aVL and aVF that were $63.7{\pm}23.0{\mu}V$, $88.0{\pm}83.6{\mu}V$, respectively. Average amplitude of the negative type showed the frequency of 78.6% in lead aVR which was $99.3{\pm}38.0{\mu}V$. 2. Average amplitude of the QRS complex were from $362.8{\pm}177.7{\mu}V$ to $532.8{\pm}253.9{\mu}V$(mean of $449.1{\pm}57.2{\mu}V$) that in all leads except lead I were manifested the Low-Voltage QRS complex(below 0.5mV). Average amplitudes of each wave type in the QRS complex aere $-50.2.4{\pm}258.2{\mu}V$ and $-428.6{\pm}195.1{\mu}V$ in the QS groups type that showed a frequency of 66.3%, 70.4% in the leads I and aVL, were $451.1{\pm}20.4.0{\mu}V$, $387.6{\pm}175.8{\mu}V$ and $299.3{\pm}146.5{\mu}V$ in the R groups type that showed a frequency of 48.0%, 53.1% and 34.7% in the leads III, aVR and aVF, and were $-307.5{\pm}180.3{\mu}V$, $201.4{\pm}77.2{\mu}V$ in the QR wave type which showed a frequency of 39.8% in lead II, respectively. 3. In T wave, amplitude of the positive type showed the frequency of 50.0%, 82.7%, 51.0% and 57.1% in leads II, III aVR and aVF which were $214.9{\pm}115.6{\mu}V$, $188.5{\pm}119.3{\mu}V$, $191.0{\pm}93.7{\mu}V$ and $165.7{\pm}91.9{\mu}V$, and the negative type showed a frequecny of 66.3% and 72.5% in leads I and aVL. that were $221.3{\pm}112.5{\mu}V$, $-173.6{\pm}86.7{\mu}V$, respectively. 4. Amplitude of ST segment in leads I, II and III were a mean of $-12.2{\pm}37.2{\mu}V$, $17.5{\pm}42.6{\mu}V$ and $28.3{\pm}40.4{\mu}V$, in leads aVR, aVL and aVF were $-3.9{\pm}32.5{\mu}V$, $-15.9{\pm}35.6{\mu}V$ and $26.2{\pm}37.5{\mu}V$, respectively.

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Damage Location Detection of Shear Building Structures Using Mode Shape (모드형상을 이용한 전단형 건물의 손상 위치 추정)

  • Yoo, Suk Hyeong;Lee, Hong Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.1
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    • pp.124-132
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    • 2013
  • Damage location and extent could be detected by the inverse analysis on dynamic response of the damaged structure. In general, detection of damage location is possible by the observation of the mode shape difference between undamaged and damaged structure and assessment of stiffness reduction is possible by the observation of the natural frequency difference of them. The study on damage detection by the dynamic response in civil structures is reported enough and in practical use, but in building structures it is reported seldom due to several problems. The purpose of this study is to present the damage detection method on shear building structures by mode shape. The damage location index using 1st mode shape is observed theoretically to find out damage location. The damage detection method is applied to numerical analysis model such as MATLAB and MIDAS GENw for the verification. Finally the shaking table test on 3 story shear building is performed for the examination of the damage detection method. In shaking table results, as the story stiffness decrease by 25% the 1st mode frequency increase by 12%, and the damage location index represents minus at damaged story.

Printed Monopole Antenna of Dual band for Omni-diractional Radiation Patterns (전방향 복사패턴의 이중대역 프린트형 모노폴안테나)

  • 이현진;임영석
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.11
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    • pp.99-104
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    • 2003
  • We are designed and fabricated the Printed dual monopole antenna with CPW feeder for PCS and IMT2000 band. In this paper il proposed modified dual monopole antenna that is transform conventional monopole antenna to get dual band frequency. The dual monopole antennas had broad bandwidth and omni -directional radiation patterns in construct with conventional monopole antenna. On a monopole operated a stub to other monopole antenna, we could obtain easy an impedance matching. It is increased band width of impedance. The antenna bandwidth is about 150MHz(1.74 ∼1.89〔GHz〕)at 1$^{st}$ resonance frequency and 290MHz(1.95∼2.24GHz) at 2$^{nd}$ resonance frequency on VSWR(equation omitted)1.5 and then we can be got not only 1.75∼1.87〔GHz〕 PCS band but also 1.92∼2.17 〔GHz〕).GHz〕).