• Journal of Magnetics
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• 제22권1호
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• pp.133-140
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• 2017

Split magnetic fluid sealing is a combination of magnetic fluid rotary and plane sealing. Using the theory of equivalent magnetic circuit design as basis, the author theorized the pressure resistance performance of magnetic fluid plane sealing. To determine the pressure resistance of magnetic fluid plane sealing, the author adopted the method of finite element analysis to calculate the magnetic field intensity in the gap between plane sealing structures. The author also analyzed the effect of different sealing gaps, as well as different ratios between the sealing gap and tooth and solt width, on the sealing performance of split magnetic fluid. Results showed that the wider the sealing gap, the lower the sealing performance. Tooth width strongly affects sealing performance; the sealing performance is best when the ratio between tooth width and sealing gap is 2, whereas the sealing performance is poor when the ratio is over 8. The sealing performance is best when the ratio between the solt width and sealing gap is 4, indicating a slight effect on sealing performance when the ratio between the solt width and sealing gap is higher. Theoretical analysis and simulation results provide reference for the performance evaluation of different sealing equipment and estimation of critical pressure at interface failure.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 제4회 영호남학술대회 논문집
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• pp.101-104
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• 2002

Abstract We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is 10[mN/m]. In processing of a device manufacture, we can see the process is good from the change of a surface pressure for organic thin films and transfer ratio of area per molecule. The structure of manufactured device is Au/Poly-${\gamma}$ Benzyl $_D$-Glutamate/Al; the number of accumulated layers is 1, 3, 5 and 7. Also, we then examined of the MIM device by means of I-V. The I-V characteristic of the device is measured from 0 to +2[V]. We determined electrochemical measurement by using cyclic voltammetry with a three-electrode system. LB film accumulated by monolayer on an ITO. In the cyclicvoltammetry, An Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode measured in $LiBF_4$ solution, stable up to 0.9V vs. Ag/AgCl.

• Geomechanics and Engineering
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• 제14권5호
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• pp.407-419
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• 2018

In order to investigate flow characteristics after water inrush from the working face in process of karst tunnel construction, numerical calculation for two class case studies of water inrush is carried out by using the FLUENT software on the background of Qiyueshan tunnel. For each class water inrush from the tunnel face, five cases under different water-inrush velocity are simulated and researched. Three probing lines are selected respectively in the left tunnel, cross passage, right tunnel and in the height direction of the tunnel centerline. The variation characteristics of velocity and pressure on each probing line under the five water-inrush velocities are analyzed. As for the selected four groups probing lines in the tunnels, the change rules of velocity and pressure on each group probing lines under the same water-inrush velocity are discussed. Finally, the water flow characteristics after inrush from the tunnel face are summarized by comparing the case studies. The results indicate that: (1) The velocity and pressure change greatly at the intersection area of the cross passage and the tunnels. (2) The velocity nearby the tunnel side wall is the minimum, while it is the maximum in the middle position. (3) The pressure value of every cross section in the tunnels is basically fixed. (4) As water-inrush velocity increases, the flow velocity and pressure in the tunnels also increase. The former is approximately proportional to their respective water-inrush velocity, while the latter is not. The research results provide a theoretical basis for making scientific and rational escape routes.

• 한국재료학회지
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• 제10권11호
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• pp.755-759
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• 2000

RF magnetron sputtering법으로 초미세결정 Fe-Sm-O계의 박막을 상온에서 제작하여 산소분압에 따른 포화자화, 보자력, 고주파에서의 투자율(100MHz)을 조사하였다. 최적조건인 5%의 산소분압에서 제조한 초미세결정 Fe(sub)83.4Sm(sub)3.4O(sub)13.2박막은 포화자속밀도 18kG, 보자력 0.82 Oe, 실효투자율 (0.5~100MHz) 2,600 이상의 우수한 연자성을 나타내었다. 산소분압이 증가함에 따라 $\alpha$-Fe 결정립의 크기가 감소하여 10%이상의 산소분압에서는 FeO가 생성되어 연자기적 성질이 열화되었다. Fe-Sm-O계 박막의 전기비저항은 산소분압이 증가함에 따라 증가하는 경향을 나타내었으며 우수한 연자기적 성질을 가지는 Fe(sub)83.4Sm(sub)3.4O(sub)13.2박막의 경우, 전기비저항은 130 $\mu$$\Omega$cm이었다. 따라서 미세하게 형성된 $\alpha$-Fe 결정립과 높은 전기비저항 때문에 초미세결정 Fe(sub)83.4Sm(sub)3.4O(sub)13.2박막이 고주파에서 우수한 연자기적 성질을 가지는 것으로 판단된다.

• 한국전기전자재료학회논문지
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• 제30권11호
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• pp.717-721
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• 2017

We studied the performance enhancement of organic light-emitting diodes (OLEDs) using 2,3,5,6-fluoro-7,7,8,8-tetracyanoquinodimethane ($F_4-TCNQ$) as the hole-transport layer. To investigate how $F_4-TCNQ$ affects the device performance, we fabricated a reference device in an ITO (170 nm)/TPD(40 nm)/$Alq_3$(60 nm)/LiF(0.5 nm)/Al(100 nm) structure. Several types of test devices were manufactured by either doping the $F_4-TCNQ$ in the TPD layer or forming a separate $F_4-TCNQ$ layer between the ITO anode and TPD layer. N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine (TPD), tri(8-hydroxyquinoline) aluminum ($Alq_3$), and $F_4-TCNQ$ layers were formed by thermal evaporation at a pressure of $10_{-6}$ torr. The deposition rate was $1.0-1.5{\AA}/s$ for TPD and $Alq_3$. The LiF was subsequently thermally evaporated at a deposition rate of $0.2{\AA}/s$. The performance of the OLEDs was considered with respect to the turn-on voltage, luminance, and current efficiency. It was found that the use of $F_4-TCNQ$ in OLEDs enhances the performance of the device. In particular, the use of a separate layer of $F_4-TCNQ$ realizes better device performance than other types of OLEDs.

• Korean Journal of Acupuncture
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• 제21권2호
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• pp.147-159
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• 2004

Objective : This study was designed to estimate the effects of Rainbow Power therapy on neck pain patients by using Visual Analogue Scale(VAS) and pressure algometer. Methods : Rainbow Power therapy group consisted of 18 patients and acupuncture therapy group consisted of 7 patients. The degree of improvement of neck pain was evaluated by VAS and pain pressure threshold(at the points of Jianjing GB21 and Jianwaishu SI14) before treatment, before 3rd treatment and before 5th treatment. Rainbow Power therapy was performed at the points of Jianjing GB21, Zhongfu LU1, Yangxi LI5, Ganshu BL18, Weishu BL21 and Shenshu, BL23. Each points were stimulated with RP-UM103(Rainbow Power therapy instrument) for 20 seconds. The points of acupuncture therapy were Jeonggeun, Jeongjong, Sangbaekn and Hegu LI4 and acupuncture was maintained for 15 minutes. After above therapy dry cupping was performed at the points of Jianjing GB21, Jianwaishu SI14, Gaohuang BL43, Tianzong, SI11 and Bingfeng SI12 for 5 minutes. Results : There was no significant difference between the two groups in VAS, pain threshold of Jianjing GB21 and Jianwaishu SI14 following treatment. In the two groups VAS was significantly decreased. In Rainbow Power therapy group the pain threshold of the two points was significantly increased. But there was no significant increase in acupuncture therapy groups about the pain threshold of Jianwaishu SI14. Conclusions : The effectiveness of Rainbow Power therapy on neck pain was shown through VAS and pressure algometer. These imply that Rainbow Power therapy may be useful for neck pain. Further study is needed about Rainbow Power therapy.

• 대한화학회지
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• 제40권8호
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• pp.557-564
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• 1996

각기 다른 양이온$(Na^+, Li^+, K^+, NH_4^+)$을 구조이성질체인 일련의 합성 올리고당에 첨가함으로써, 양이온의 결합정도가 올리고당의 연결위치에 따라 달라지리라는 것을 FAB CAD MS/MS(Fast Atom Bombardment Collision Activated Dissociation Mass Spectrometry/ Mass Spectrometry)를 이용하여 안정성 측면에서 연구하였다. 알카리 양이온화된(cationized) 올리고당들은 양성자화(protonated)된 형태보다 더 큰 안정성을 나타내어 -40 eV의 충돌 에너지 수중에서 연결부위와 작용기들이 분절된 스펙트럼형태를 보인 반면, 양성자화된 올리고당은 -10 eV에서 에서 같은 정도의 분절을 보였다. 첨가된 양이온 중, 칼륨 양이온이 첨가된 올리고당이 다른 것에 비해 안정화되어 triple quadrupole기종의 허용에너지 조건하에서는 분절이온을 생성하지 않는다. 다른 양이온화된 올리고당들은 충돌기체인 argon의 압력이 0.8mTorr 상태에서 양이온의 종류에 따라$Nap^+>Li^+>NH_4^+$순으로 안정성을 나타내었다. 올리고당과 결합하는 금속양이온들은 질소를 포함하고 있는 아미노당에 위치하며, 이는 아미노당을 포함하는 분절이온마다 각 양이온에 해당하는 만큼의 질량이 이동된 분절피크들이 나타나는 것으로 설명 가능하다. 또한 양이온화된 것이 양성자화된 것보다 더 큰 안정성을 지니는 이유는 금속 양이온과 아미노당의 N-acetyl 작용기 및 fucose의 산소 사이에 크라운에테르 형태의 결합을 형성하는 것으로 설명할 수 있다. 이 때 참여한 금속 양이온의 크기 및 연결위치-이성질 부분의 구조적 형태에 따라 결합정도의 차이를 보여 각기 다른 분절스펙트럼의 형태를 나타내며 안정성면에서도 1-6>1-4>1-3 연결위치의 순으로 나타났다.

• Advanced Composite Materials
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• 제18권4호
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• pp.381-394
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• 2009

The kinetics of centrifugal infiltration of fibrous tubular preform is built theoretically, and simulations are conducted to study the effects of various casting conditions on infiltration kinetics and macrosegregation by combining with the energy, mass and kinetic equations. A similarity way is used to simplify the one-dimensional model and the parameter is ascertained by an iterative method. The results indicate that the increase of superheat, initial preform temperature, porosity tends to enlarge the remelting region and decrease copper solute concentration at the infiltration front. Higher angular velocity leads to smaller remelting region and solute concentration at the tip. The pressure in the infiltrated region increase significantly when the angular velocity is much higher, which requires a stronger preform. It is observed that the pressure distribution is mainly determined by the angular velocity, and the macrosegregation in the centrifugal casting is greatly dependent on the superheat of inlet metal matrix, initial temperature and porosity of the preform, and the angular velocity.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 2002년도 학술대회지
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• pp.27-34
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• 2002

Clinical study on hemodynamics of healthy elders before and after tread mill. Using doubleblind, placebo-controlled study design. Seventy-five 50-70 years old volunteers without organic disease were divided into two groups, Ginseng group and control group. Each subject was received 3 g Korea Red Ginseng (KRG) capsules or placebo per day for 4 weeks. Before and after administration 4 weeks, the symptoms were asked and hemodynamics parameter such as pump function, systolic function, preload and afterload were recorded before and after tread mill 1,5, 10 minutes by the method of thoracic impedance cardiograph. The result showed that Ginseng could improve quality of life, had obvious effect of increasing PEP (pre-ejection period), PEP/LVET (pre-ejection period/left ventricular ejection period), PCWP (wedged pressure pulmonary capillary). The change rate of HR (heart rate), SV (stroke volume) in KRG group were much lowered, while EF (ejection fraction), LVET (left ventricular ejection period), LVEDP (left ventricular end diastolic pressure) was recovered much quickly. The circulation showed Ginseng could improve the quality of life though its promoting circulation function which are increasing both the systolic function and the preload.

• Computers and Concrete
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• 제29권4호
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• pp.209-217
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• 2022

In order to analyze the static and dynamic structural characteristics of the Obermeyer gate under overflow conditions, the force characteristics and vibration characteristics of the shield plate structure are studied based on the fluid-solid coupling theory. In this paper, the effects of the flow rate, airbag pressure and overflow water level on the structural performance of shield plate of air shield dam are explored through the method of controlling variables. The results show that the maximum equivalent stress and total deformation of the shield plate decrease first and then increase with the flow velocity. In addition, they are positively correlated with the airbag pressure. What's more, we find that the maximum equivalent stress of the shield plate decreases first and then increases with the overflow water level, and the total deformation of the shield plate decreases with the overflow water level. What's more importantly, the natural frequency of the shield structure of the Obermeyer gate is concentrated at 50 Hz and 100 Hz, so there is still the possibility of resonance. Once the resonance occurs, the free edge of the shield vibrates back and forth. This work may provide a theoretical reference for the safe and stable operation of the shield of the Obermeyer gate.