• 제목/요약/키워드: internal diffusion

검색결과 307건 처리시간 0.031초

The Upper Ascending Reticular Activating System between Intralaminar Thalamic Nuclei and Cerebral Cortex in the Human Brain

  • Jang, Sungho;Kwak, Soyoung
    • The Journal of Korean Physical Therapy
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    • 제29권3호
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    • pp.109-114
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    • 2017
  • Purpose: The ascending reticular activating system (ARAS) is responsible for regulation of consciousness. In this study, using diffusion tensor imaging (DTI), we attempted to reconstruct the thalamocortical projections between the intralaminar thalamic nuclei and the frontoparietal cortex in normal subjects. Methods: DTI data were acquired in 24 healthy subjects and eight kinds of thalamocortical projections were reconstructed: the seed region of interest (ROI) - the intralaminar thalamic nuclei and the eight target ROIs - the medial prefrontal cortex, dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, orbitofrontal cortex, premotor cortex, primary motor cortex, primary somatosensory cortex, and posterior parietal cortex. Results: The eight thalamocortical projections were reconstructed in each hemisphere and the pathways were visualized: projections to the prefrontal cortex ascended through the anterior limb and genu of the internal capsule and anterior corona radiata. Projections to the premotor cortex passed through the genu and posterior limb of the internal capsule and middle corona radiata; in contrast, projections to the primary motor cortex, primary somatosensory cortex, and posterior parietal cortex ascended through the posterior limb of the internal capsule. No significant difference in fractional anisotropy, mean diffusivity, and fiber volume of all reconstructed thalamocortical projections was observed between the right and left hemispheres (p>0.05). Conclusion: We reconstructed the thalamocortical projections between the intralaminar thalamic nuclei and the frontoparietal cortex in normal subjects. We believe that our findings would be useful to clinicians involved in the care of patients with impaired consciousness and for researchers in studies of the ARAS.

마이크로 펄스 플라즈마 질화에 의해 생성된 금형 공구강의 표면층에 관한 연구 -공정 변수의 영향- (The Microstructures and Properties of Surface Layer on the Tool Steel Formed by Ion Nitriding -Effects of Process Parameter-)

  • 이재식;김한군;유용주
    • 열처리공학회지
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    • 제14권1호
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    • pp.8-16
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    • 2001
  • The effects of gas composition, pressure, temperature and time on the case thickness, hardness and nitride formation in the surface of tool steels(STD11 and STD61) have been studied by micro-pulse plasma nitriding. External compound layer and internal diffusion layer and the diffusion layer were observed in the nitrided case of tool steels. The relative amounts and kind of phases formed in the nitrided case changed with the change of nitriding conditions. Generally, only nitride phases such as ${\gamma}(Fe_4N)$, ${\varepsilon}(Fe_{2-3}N)$, or $Cr_{1.75}V_{0.25}N_2$ phases were detected in the compound layer, while nitride and carbide phases such as ${\varepsilon}-nitride(Fe_{2-3}N)$, $(Cr,Fe)_{\gamma}C_3$ or $Fe_3C$ were detected in the diffusion layer by XRD analysis. The thickness of compound layer increased with the increase of nitrogen content in the gas composition. Maximum case depth was obtained at gas pressure of 200Pa.

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단단한 종양 안에 수동 조준된 약물의 전달에 관한 확산에 기초한 모델 이론 (A Diffusion-based Model Theory of Passive-Targeted Drug Delivery in Solid Tumors)

  • 최준혁;강남룡;최상돈
    • 한국의학물리학회지:의학물리
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    • 제18권3호
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    • pp.161-166
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    • 2007
  • 공모양의 단단한 종양안에서 수동조준된 약물의 전달에 관한 모델이론이 적절한 경계조건과 초기조건하에서 픽의 확산법칙으로부터 유도된다. 종양안의 농도는 초기값이 일정하면 시간과 지름의 함수로 나타난다. 생각실험(사고실험)으로부터 예측되는 바와 같이, 농도는 시간이 경과함에 따라 평형값에 접근한다. 시간에 따른 농도의 변화는 조직안의 약물의 확산계수, 종양의 크기, 주입된 약물의 양, 경계면에서의 농도의 물매(gradient)에 의해 결정된다.

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폐기물 처리시설에서의 악취 및 환기에 관한 연구 (A study on odor and ventilation in waste treatment facilities)

  • 서병석;전용한
    • Design & Manufacturing
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    • 제14권2호
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    • pp.28-33
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    • 2020
  • Recently, as the income level and quality of life have improved, the desire for a pleasant environment has increased, and a deodorization plan is required through thorough prevention and diffusion of odorous substances in waste treatment facilities recognized as hateful facilities, appropriate collection, and selection of the right prevention facilities. In this study, a waste disposal facility was modeled and computerized analysis for odor and ventilation analysis was conducted. Numerical analysis of the waste treatment facility was performed at the size of the actual plant. CATIA V5 R16 for numerical model generation and ANSYS FLUENT V.13 for general purpose flow analysis were used as analysis tools. The average air-age of the internal was 329 seconds, and the air-flow velocity was 0.384m/s. The odor diffusion analysis inside the underground pump room showed congestion-free air circulation through streamline distribution and air-age distribution. This satisfies the ASHRAE criteria. In addition, the results of diffusion analysis of odorous substances such as ammonia, hydrogen sulfide, methyl mercaptan and dimethyl sulfide were all expected to satisfy the regulatory standards. Particularly in the case of the waste loading area, the air-flow velocity was 0.297m/s, and the result of meeting the regulatory standards with 0.167ppm of ammonia, 0.00548ppm of hydrogen sulfide, 0.003ppm of methyl mercaptan, and 0.003ppm of dimethyl sulfide was found.

Applications of Diffusion Tensor MRI to Predict Motor Recovery of Stroke Patients in the Chronic Stages

  • Tae, Ki-Sik;Song, Sung-Jae;Kim, Young-Ho
    • 대한의용생체공학회:의공학회지
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    • 제29권2호
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    • pp.114-121
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    • 2008
  • Within 2 to 5 months after stroke, patients recover variable degrees of function, depending on the initial deficit. An impaired hand function is one of the most serious disability in chronic stroke patients. Therefore, to evaluate the extent of motor dysfunction in the hemiplegic hand is important in stroke rehabilitation. In this paper, motor recoveries in 8 chronic stroke patients with Fugl-Meyer (FM) and white matter changes before and after the training program with a designed bilateral symmetrical arm trainer (BSAT) system were examined. The training was performed at 1 hr/day, 5 days/week during 6weeks. In all patients, FM was significantly improved after the 6-week training. Diffusion tensor imaging (DTI) results showed that tractional anisotropy ratio (FAR) and fiber tracking ratio (FTR) in the posterior internal capsule were significantly increased after the training. It seemed that the cortical reorganization was induced by the 6 week training with the BSAT. In all parameters proposed this study, a significant correlation was found between these parameters (FAR and FTR) and motor recoveries. This study demonstrated that DTI technique could be useful in predicting motor recovery in chronic hemiparetic patients.

혁신확산이론 관점에서의 Green SCM 도입 및 영향요인과 성과에 관한 실증연구 (An Empirical Study on the Influencing Factors, Practice Level, and Performanc of Green Supply Chain Management From the Innovation Diffusion Theory Perspective)

  • 이영찬;오형진
    • 지식경영연구
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    • 제11권5호
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    • pp.59-78
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    • 2010
  • In this paper, we arrange the concept of 'Green' in SCM after literature study of Green SCM and investigate causal relationships between influencing factors, practice level and environmental performance focused on Korean firms empirically and conduct path analysis for hypothesis test using partial least squares regression with bootstrap. Firstly, we divide influencing factors of Green SCM into environmental and organizational factors through the previous studies of innovation diffusion theory and environmental management theory, and then we selected 'uncertainty', 'competitiveness' as the environmental factors and 'top management support', 'perceived benefit', 'training' as the organizational factors. Secondly, we classify practice level of Green SCM into 'internal environmental management', 'green purchasing', 'eco-design'. Finally, we selected 'financial performance', 'environmental performance' as the organizational performance. We conducted a survey on the middle manager of manufacturing companies implementing SCM and an empirical analysis. The results of analysis show that there exist causal relationships between influencing factors, practice level, and environmental performance of Green SCM. We expect that the result of this study will suggest useful information to managers who are responsible for SCM to design and execute Green SCM in strategic perspectives.

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와류진동 조절에 의한 유동가진 공동 내부의 음압 제어 (Control of Sound Pressure inside a Flow Excited Cavity by Regulation of Vorticity Shedding)

  • 박종범;황철호
    • 한국소음진동공학회논문집
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    • 제17권12호
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    • pp.1223-1229
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    • 2007
  • Flow traveling over a cavity opening forms a vortex due to unstable shear layer and induces an aerodynamic pressure excitation from the diffusion of the vortex convecting out of the trailing edge of the opening. The interaction between the excitation force and the cavity response sustains resonance in the resonator(cavity) and locked-in vortex shedding at the leading edge of the opening. The aerodynamic excitation force can be described from the diffusion of the vortex over the trailing edge and the level of its diffusivity is related to the strength of vorticity seeded at the leading edge. In this study, the control scheme of the internal pressure oscillation was proposed from regulating the vorticity at the leading edge by use of an oscillating spoiler. It was found that the relative motion between the spoiler and the air mass at the cavity opening influenced vorticity strength and the control was achieved by direct feedback of the cavity pressure fluctuation to the actuator.

전자무역의 활용수준과 성과 영향 요인에 관한 연구의 종합 분석 (A Total Analysis of Study on Factor Affecting the Usage Level and Performance of e-trade)

  • 이용근;김승철;정재우
    • 통상정보연구
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    • 제6권1호
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    • pp.99-126
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    • 2004
  • E-Trade is expected to dominate the global trade in the 21st century and thus is being introduced as a major policy assignment for each development country. e-trade has the potential to accelerate existing trends and introduce new ways of conducting trade. and e-trade is an alternative to strengthen international competitiveness. therefore, we needs to quickly adjust to this new method of e-trade and provide a number of policy suggestions that it can make best use of. However, successful implemetation, diffusion and usage of e-trade system require cooperation, commitment and the trust of all participating members in international trade process. A number of interorganizational, intraorganizational and innovation factors can influence both the extent to which e-trade is diffused and the level of subsequent performance that accure to participating firms. Considering the characteristics of e-trade, the proposed factors are based on an interdisciplinary study. The research model is based on the theories of innovation diffusion, inter-organizational system, and IS implementation. The factors proposed for this study of external firm factors, internal firm and perception factors.

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유동가진 공명기 내부의 음압 제어 (Control of Sound Pressure Inside a Flow Excited Resonator)

  • 황철호;박종범
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2005년도 추계학술대회논문집
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    • pp.196-199
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    • 2005
  • Flow traveling over a cavity opening forms a vortex due to unstable shear layer and induces an aerodynamic pressure excitation from the diffusion of the vortex convecting out of the trailing edge of the opening. The interaction between the excitation force and the cavity response sustains resonance in the resonator(cavity) and locked-in vortex shedding at the leading edge of the opening. The aerodynamic excitation force can be described from the diffusion of the vortex over the trailing edge and the level of its diffusivity is related to the strength of vorticity seeded at the loading edge. In this study, the control scheme of the internal pressure oscillation was proposed from regulating the vorticity at the leading edge by use of an oscillating spoiler. It was found that the relative motion between the spoiler and the air mass at the cavity opening influenced vorticity strength and the control was achieved by direct feedback of the cavity pressure fluctuation to the actuator.

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Finite Element Method (FEM) Study on Space Charge Effects in Organic Light Emitting Diodes (OLED)

  • Kim, Kwang-Sik;Hwang, Young-Wook;Won, Tae-Young
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제12권4호
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    • pp.467-472
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    • 2012
  • In this paper, we present a finite element method (FEM) study on the space charge effects in organic light emitting diodes. The physical model covers all the key physical processes in OLEDs, namely charge injection, transport and recombination, exciton diffusion, transfer and decay as well as light coupling, and thin-film-optics. The exciton model includes generation, diffusion, and energy transfer as well as annihilation. We assumed that the light emission originates from oscillation which thus is embodied as exciton in a stack of multilayer. We discuss the accumulation of charges at internal interfaces and their signature in the transient response as well as the electric field distribution. We also report our investigation on the influence of the insertion of the emission layer (EML) in the bilayer structure.