• Title/Summary/Keyword: Seon-bi

Search Result 122, Processing Time 0.043 seconds

Microstrip Patch Array Antenna Using Low Temperature Co-Fired Ceramic Substrates for 60 GHz WP AN Applications (적층 세라믹 기판을 이용한 60 GHz WPAN총 2X4 배열 안테나)

  • Byun, Woo-Jin;Kim, Bong-Su;Kang, Min-Soo;Kim, Kwang-Seon;Kim, Jong-Myun;Song, Myung-Sun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.19 no.12
    • /
    • pp.1402-1409
    • /
    • 2008
  • In this paper, a low temperature co-fired ceramic cavity backed antenna in order to improve the performances of radiation and bandwidth for the antenna with high relative dielectric constant is proposed. Low temperature co-fired ceramic cavity consisted of several ground planes with closely spaced metallic vias connected. It is shown that the size of a low temperature co-fired ceramic cavity has the effects on the performances of radiation and bandwidth for the antenna. The proposed 2x4 low temperature co-fired ceramic cavity backed antenna is $10{\times}20\;mm^2$ in size. Measured results show antenna gain of $11.8{\sim}14.1\;dBi$ and bandwidth of 13 %(7.9 GHz) in the $57{\sim}64\;GHz$ band.

Biomechanical Analysis of Lower Limb Joint Motions and Lumbar Lordosis during Squat and Stoop Lifting (쪼그려 들기와 허리 굽혀 들기 시 하지관절 움직임과 요추 전만에 관한 생체역학적 분석)

  • Hwang, Seon-Hong;Kim, Young-Eun;Kim, Young-Ho
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.25 no.11
    • /
    • pp.107-118
    • /
    • 2008
  • In this study, lower extremity joint kinematics and kinetics and lumbar lordosis were investigated for two different symmetrical lifting techniques(squat and stoop) using the three-dimensional motion analysis. Twenty-six male volunteers lifted boxes weighing 5, 10 and 15kg by both squat and stoop lifting techniques. There were not significant differences in maximum lumbar joint moments between the two techniques. The hip and ankle contributed the most part of the support moments during squat lifting, and the knee flexion moment played an important role in stoop lifting. The hip, ankle and lumbar joints generated power and only the khee joint absorbed power in the squat lifting. The knee and ankle joints absorbed power, the hip and lumbar joints generated power in the stoop lifting. The bi-articular antagonist muscles' co-contraction around the knee joint during the squat lifting and the eccentric co-contraction of the gastrocnemius and semitendinosus were found to be important for straightening up during the stoop lifting. At the time of lordotic curvature appearance in the squat lifting, there were significant correlations in all three lower extremity joint moments with the lumbar joint. Differently, only the hip moment had significant correlation with the lumbar joint in the stoop lifting. In conclusion, the knee extension which is prominent kinematics during the squat tilling was produced by the contributions of the kinetic factors from the hip and ankle joints(extensor moment and power generation) and the lumbar extension which is prominent kinematics during the stoop lifting could be produced by the contributions of the knee joint kinetic factors(flexor moment, power absorption, bi-articular muscle function).

단일 나노선의 열전물성 측정용 열전 MEMS 플랫폼 개발

  • Sin, Ho-Seon;Jeon, Seong-Gi;Lee, U;Yu, Jin;Song, Jae-Yong
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2013.02a
    • /
    • pp.589-589
    • /
    • 2013
  • 열전재료는 제백효과(Seebeck effect)에 의해 폐열을 전기에너지로 변환시킬 수 있는 소재로서, 기존의 열전재료가 나노수준으로 크기가 줄어들 경우 양자제한효과에 의한 제백계수의 증가와 표면산란에 의한 열전도도 감소로 인해 벌크재료에 비해 높은 에너지변환효율을 가질 수 있을 것으로 기대되고 있다. 에너지 변환효율은 열전성능계수인 $ZT=S2{\sigma}T/k$로 정의되며 따라서 우수한 열전재료는 높은 제백계수 S와, 높은 전기전도도 ${\sigma}$ 및 낮은 열전도도 k를 갖는 재료여야 한다. 그러나 나노소재는 낮은 측정 신호와 측정소자준비가 어려워 기존 측정시스템으로는 원활한 측정이 어렵다. 특히 열전도도의 경우 나노소재 자체의 열전도 보다 나노소재 주변 구조에 의한 열전도가 큰 경우 정확한 열전도도 평가가 어렵다. 본 연구에서는 나노선의 열전물성을 평가하기 위해 MEMS기반 기술을 이용하여 열전물성 측정플랫폼(MEMS-based thermoelectric measurement platform, MTMP)을 개발하였다. 개발 된 MTMP는 얇은 Si nitride 브릿지들이 허공에 떠 있는 두 개의 아일랜드 형태의 멤브레인 구조를 지지하는 형태로 제작되었으며, 한 쪽 아일랜드구조 위에는 나노히터가 있어 두 아일랜드 구조 사이에 온도구배를 만들 수 있도록 제작되었다. 제작된 멤브레인을 이용하여 전기화학적인 방법으로 합성한 Bi-Te계 나노선의 S, ${\sigma}$ 그리고 k를 측정하였다. 측정결과 화학양론적 미세구조를 갖는 단결정 Bi2Te3 나노선은 300 K의 측정온도에서 $S=-57{\mu}V/K$, ${\sigma}=3.9{\times}10^5S/m$, k=2.0 W/m-K의 측정 값으로 ZT=0.19였다. 본 연구에서 개발한 MTMP는 나노선 뿐만 아니라 나노플레이트의 열전 측정에도 활용할 수 있는 구조로서 나노열전소재 측정에 널리 활용될 수 있다.

  • PDF

(Design of RFID Reader Antenna Using Two Orthogonally Oriented 1x2 Sub-Arrays at 433 MHz) (직교형으로 배열된 2개의 1x2서브-어레이를 이용한 433MHz에서 동작하는 RFID 리더용 안테나 설계)

  • Kim Jong-Sung;Park Seung-Mo;Choi Won-Kyu;Seong Nak-Seon
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.42 no.9 s.339
    • /
    • pp.97-100
    • /
    • 2005
  • An orthogonal antenna is presented for reader application of radio frequency identification (RFID) at 433 MHz. Two 1x2 sub-arrays are orthogonally placed on a ground plane and two different feeding networks are applied to control horizontal and vertical radiation current flows for each sub-array, respectively. Inverted-F structures are used as radiation elements and can generate two linear polarizations by relative current distribution of radiators forming sub-arrays. Antenna gains are 2.7 and 0.4 dBi and isolation between two input ports is less than 25dB.

Correlations between Neurologic and Psychiatric Symptoms in Acute Stroke Patients (급성기 뇌졸중 환자에서 신경 및 정신 증상간 상호관계)

  • Kang, Hee-Ju;Bae, Kyung-Yeol;Kim, Sung-Wan;Kim, Jae-Min;Shin, Il-Seon;Park, Man-Seok;Cho, Ki-Hyun;Yoon, Jin-Sang
    • Korean Journal of Psychosomatic Medicine
    • /
    • v.20 no.2
    • /
    • pp.98-104
    • /
    • 2012
  • Objectives : This study aimed to investigate the correlations between neurological and psychiatric symptoms at two weeks after stroke. Methods : For 412 stroke patients, stroke severity was evaluated by the National Institutes of Health Stroke Scale(NIHSS), disability by the Barthel Index(BI) and modified Rankin Scale(mRS), cognitive function by the Korean Mini-Mental State Examination(K-MMSE), and muscle power by grip strength. Psychiatric symptoms were assessed by Symptom check list-90-Revision(SCL-90-R), consisted of nine symptom domains : Somatization, Obsessive-compulsive, Interpersonal sensitivity, Depression, Anxiety, Hostility, Phobic anxiety, Paranoid ideation, Psychoticism, and Additional items. The correlations between the neurological and psychiatric symptoms were investigated at the time of admission and before discharge(i.e. before and after treatment). Results : At the time of admission, NIHSS score was associated with scores on Phobic anxiety and Additional items ; and scores on BI and mRS were associated with Depression, Phobic anxiety and Additional items. At the time of discharge, NIHSS score was associated with scores on Somatization, Depression, Phobic anxiety, and Additional items ; scores on BI and mRS were associated with scores on Depression, Phobic anxiety and Additional items ; MMSE score was associated with Obsessive-compulsive, Depression, Phobic anxiety, and Additional items ; and grip strength was associated with Somatization, Depression, Anxiety and Additional items. Conclusions : More severe neurological symptoms were associated with higher psychiatric morbidity particularly in depression, phobic anxiety, sleep and appetite disturbance at acute stage of stroke. More intensive psychiatric care and intervention are needed for the high risk group.

  • PDF

Magnetite and Scheelite-Bearing Skarns in Ulsan Mine, Korea (울산 광산의 철-텅그스텐 스카른화작용)

  • Choi, Seon-Gyu;Imai, Naoya
    • Economic and Environmental Geology
    • /
    • v.26 no.1
    • /
    • pp.41-54
    • /
    • 1993
  • The Ulsan Fe-W deposit, which can be classified as a calcareous skarn deposit, is represented by ore pipe consisting principally of magnetite and lesser amounts of scheelite with minor sulphides, sulphosaits, arsenides, sulpharsenides, etc. At Ulsan mine, metasomatic processes of skarn growth may be divided broadly into two stages based on the paragenetic sequence of calc-silicate minerals and their chemical composition; early and late skarn stages. Early stage has started with the formation of highly calcic assemblages of wollastonite, diopsidic clinopyroxene and nearly pure grossular, which are followed by the formation of clinopyroxenes with salite to ferrosalite composition and grandite garnets with intermediate composition. Based on these calc-silicate assemblages, the temperatures of early skarn formations have been in the ranges of $550^{\circ}$ to $450^{\circ}$. The calc-silicate assemblages formed during the earlier half period of late skarn stage show the enrichment of notable iron and slight manganese, and the depletion of magnesium; clinopyroxenes are hedenbergitic, and grandite garnets are andraditic. The formation temperatures during this skarn stage are inferred to have been in the range of $430^{\circ}$ to $470^{\circ}C$ at low $X_{CO_2}$ by data from fluid inclusions of late andraditic garnets. The later half period of late skarn stage is characterized by the hydrous alteration of pre-existing minerals and the formation of hydrous silicates. The main iron-tungsten mineralization representing prominent deposition of magnetite immediately followed by minor scheelite impregnation has taken place at the middle of early skarn stage, while complex polymetallic mineralization has proceeded during and after the late skarn stage. Various metals and semimetals of Fe, Ni, Co, Cu, Zn, As, Mo, Ag, In, Sn, Sb, Te, Pb and Bi have been in various states such as native metal, sulphides, arsenides, sulphosaits, sulpharsenides and tellurides.

  • PDF

Synthesis and Characterization of Upconversion Nanoparticles for Cancer Therapy

  • Choe, Seung-Yu;Kim, Bo-Bae;Kim, Eun-Bi;Lee, Seung-U;Jeon, Seon-A;Park, Tae-Jeong
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2016.02a
    • /
    • pp.420.2-420.2
    • /
    • 2016
  • Various fields have been paid attention to upconversion nanoparticles (UCNPs) because of its unique optical properties. Moreover, to use the UC luminescent techniques through cell images for identified apoptosis/necrosis of cancer cells have been performed. They have been studied for a versatile biomedical application such as a biosensing tool, or delivery of active forms of medicines inside living cells. UCNPs have distinctive characteristics such as photoluminescence, special emission, low background fluorescence signal and good colloidal stability, which have many advantages compared with the organic dyes and quantum dots. UCNPs have not only a great potential for imaging (UC luminescence) but also therapies (photo-thermal therapy, PTT and photo-dynamic therapy, PDT) in cancer diagnostics. Therefore, we report the enhancement of upconversion red emission in NaYF4:Yb3+,Er3+ nanoparticles, synthesized via solid-state method with the thermal decomposition of trifluoroacetate as precursors and organic solvent at a high boiling point. The UCNPs have an emission in the field of near infrared wavelength, cubic shape and nano-size in length. In this study, we will further investigate it for cancer therapy with NIR optical detection onto the solid substrate.

  • PDF

Dispersive Activity and Physical Properties of Exopolysaccharide (Cystan) produced by Cystobacter sp. MSL-9

  • Lee, Gang-Mo;Kim, Se-Gyeong;Lee, Mun-Won;Choe, Seon-Yeong;Lee, Un-Taek;Yun, Hyeon-Sik
    • 한국생물공학회:학술대회논문집
    • /
    • 2003.04a
    • /
    • pp.719-723
    • /
    • 2003
  • The dispersing activity and physical properties of exopolysaccharide (Cystan) produced by Cystobacter sp. MSL-9 was studied. Dispersing activity of Cystan was measured by using bentonite, calcium carbonate, and kaolin. Rheological properties of Cystan were investigated by using a rheometer MCR300. It was found that dispersing activity of Cystan was maintained under various pH and temperature conditions. A particle size analyzer BI-9000AT was used for the particle size measurement of Cystan in aqueous solution. The high dispersing activity and stability under various pH and temperature conditions showed the feasibility of Cystan as a industrial biodispersant.

  • PDF

Production optimization of flying fish roe analogs using calcium alginate hydrogel beads

  • Ha, Bom-Bi;Jo, Eun-Hee;Cho, Suengmok;Kim, Seon-Bong
    • Fisheries and Aquatic Sciences
    • /
    • v.19 no.7
    • /
    • pp.30.1-30.7
    • /
    • 2016
  • Due to decreased supplies of marine resources and byproducts, new processing technologies for the development of analogs for natural fishery products are becoming increasingly important in the fishing industry. In the present study, we investigated the optimal processing conditions for flying fish roe analogs based on alginate hydrogels. Optimized processing of these analogs was performed by response surface methodology. The optimal processing conditions for the flying fish roe analogs (based on sphericity) were at a sodium alginate concentration of 2.41 %, calcium chloride solution curing time of 40.65 min, calcium chloride concentration of 1.51 %, and a reactor stir speed of $254{\times}g$. When the experiment was performed under these optimized conditions, the size (mm), sphericity (%), and rupture strength (kPa) of the analogs were $2.2{\pm}0.12$, $98.2{\pm}0.2$, and $762{\pm}24.68$, respectively, indicating physical properties similar to their natural counterparts.

An Approximation Method in Collaborative Optimization for Engine Selection coupled with Propulsion Performance Prediction

  • Jang, Beom-Seon;Yang, Young-Soon;Suh, Jung-Chun
    • Journal of Ship and Ocean Technology
    • /
    • v.8 no.2
    • /
    • pp.41-60
    • /
    • 2004
  • Ship design process requires lots of complicated analyses for determining a large number of design variables. Due to its complexity, the process is divided into several tractable designs or analysis problems. The interdependent relationship requires repetitive works. This paper employs collaborative optimization (CO), one of the multidisciplinary design optimization (MDO) techniques, for treating such complex relationship. CO guarantees disciplinary autonomy while maintaining interdisciplinary compatibility due to its bi-level optimization structure. However, the considerably increased computational time and the slow convergence have been reported as its drawbacks. This paper proposes the use of an approximation model in place of the disciplinary optimization in the system-level optimization. Neural network classification is employed as a classifier to determine whether a design point is feasible or not. Kriging is also combined with the classification to make up for the weakness that the classification cannot estimate the degree of infeasibility. For the purpose of enhancing the accuracy of a predicted optimum and reducing the required number of disciplinary optimizations, an approximation management framework is also employed in the system-level optimization.