• 제목/요약/키워드: stiffness method

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The study of clinical usefulness of Si-Zong-Sue-Ge(四總穴歌) (사총혈가(四總穴歌)에 관(關)한 연구(硏究))

  • Yang, Gi-Joong;Bae, Geyn-Tae;Yoon, Jong-Hwa
    • Journal of Acupuncture Research
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    • v.17 no.1
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    • pp.1-12
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    • 2000
  • Ge-Fu(歌賦) means prose and poetry individually, and they both have a meaning of all the rhythmical poetrical compositions making it ease for people to remember the content. All the Ge-Fus used in oriental medicine are made in Yuan(元), Mine(明)and Qing(靑)dynasty, and they have been largely used in most of all the fields of medicine such as Ben-Cao(本草), Tang-Ye(湯液), Zhen-Jiu(鍼灸), Zhen-Duan(診斷). Zhen-Jiu-Ge-Fu(鍼灸歌賦) has about 90 poetries and 10 proses and they contain the names of meridian; courses of meridian streams; accurate positions of acupuncture points; functions; effects; meanings of the name of acupuncture points; usages and effects of special points; manipulations of reinforcing and reducing method; contraindications of acupuncturing; principles of selections and orders of acupuncture points in therapy; and eight diadgoses. Zhen-Jiu-Ge-Fu is subdivided into Jing-Xue(經穴歌), Zhi-Jiu-Ge(刺灸歌), Shu-Xue-Ge(輸穴歌), Zhi-Liao-Ge(治療歌). And In Zhi-Liao-Ge, the most brief and essential Ge-Fu-Si-Zong-Sue-Ge- contains theraputic designs using far apart acpuncture points from the right painful areas in the body. In this study, the author opinionated the Si-Zong-Sue-Ge can be the prototype of the distant needling; the research on this can open the importance of Ge-Fus. On conclusion, 1. "Upper and lower Abdomen - Zu-San-Li($S_{36}$) (肚腹三里留)" means when there are problems and disorders in upper and lower abdomen, distinctively, such as gastric pain, maldigestion, flatulence, abdominal pain, constipation, diarrhea, vomiting, menstrual disorer, knee pain and tonic functioning, 족삼리 can be a right choice for distant needling point for treating. 2. "Face and Eye-He-Gu($Li_4$) (面目合谷收)" means when there are problems and disorders in facial, eye, ear, nose, throat, mouth regions, distinctively, such as facial edema, toothache, headache, sore throat, rhinorrhea, frontal headache, abdominal pain, dizziness, He-Gu can be a right choice for distant needling point for treating. 3. "Upper and lower back - Wei-Zhong($B_{40}$) (腰背委中求)" means when there are problems and disorders in upper and lower back, distinctively, such as upper back pain, lumbargo, hamstring muscle pain, popliteal region pain, lower extremity compartment syndrom, Inguinal region pain, muscle twitch, vomiting and diarrhea, hemorrhoidal bleeding, skin rash, Wei-Zhong can be a right choice for distant needling point for treating. 4. "Head and neck - Lie-Que($L_7$) (頭項審列缺)" means when there are problems and disorders in capital and nuchal area, distinctively, such as migraine, frontal headache, rhinorrhea, asthmatic dyspnea, aphasia, coughing, neck stiffness, occipital headache, upper extremity pain, Lie-Que can be a right choice for distant needling point for treating.

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Optimum Design of Steel-Deck System for Two-Story Roads (2층도로용 강구조 덱 시스템의 최적설계)

  • Cho, Hyo Nam;Min, Dae Hong;Kim, Hyun Woo
    • Journal of Korean Society of Steel Construction
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    • v.10 no.3 s.36
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    • pp.553-564
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    • 1998
  • Recently, more and more steel-deck structural system for two story roads has been adopted as a solution against traffic congestion in urban area, mainly because of fast construction, reduced self-weight, higher stiffness and efficient erection compared to that of concrete decks. The main objective is to study on the unit-elective optimal type and proportioning of a rational steel-deck system for two story roads using an optimum design program specifically developed for steel-deck systems. The objective function for the optimization is formulated as a minimum cost design problem. The behavior and design constraints are formulated based on the ASD(Allowable Stress Design) criteria of the Korean Bridge Design Code. The optimum design program developed in this study consists of two steps - the first step for the optimization of the steel box or plate girder viaducts, and the second step for the optimum design of the steel-decks with closed or open ribs. A grid model is used as a structural analysis model for the optimization of the main girder system, while the analysis of the deck system is based on the Pelican-Esslinger method. The SQP(Sequential Quadratic Programming) is used as the optimization technique for the constrained optimization problem. By using a set of application examples, the rational type related to the optimized steel-deck system designs is investigated by comparing the cost effectiveness of each type. Based on the results of the investigation it may be concluded that the optimal linear box girder and deck system with closed ribs may be utilized as one of the most rational and economical viaducts in the construction of two-story roads.

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Ablative Mechanism of SiC Coated Carbon/carbon Composites with Ratio of Oxygen to Fuel at Combusion Test (연소시험에서 산소와 연료 비에 따른 탄화규소로 코팅된 탄소/ 탄소 복합재의 삭마 메커니즘)

  • Zhang, Eun-Hee;Kim, Zeong-Baek;Joo, Hyeok-Jong
    • Applied Chemistry for Engineering
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    • v.18 no.3
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    • pp.227-233
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    • 2007
  • Carbon/carbon (C/C) composites as unique materials possess exceptional thermal resistance with light weight, high stiffness, and strength even at high temperature. However, one serious obstacle for application of the C/C composites is their poor oxidation resistance in high temperature oxidizing environments. SiC coating has been employed to protect the composites from oxidation. This study explored combustion characteristics of 4-directional (4D) carbon/carbon composites using liquid fuel rocket engine to investigate ablative motion of the materials. C/C composites were made of coal tar pitch as a matrix precursor, and heat-treated at $2300^{\circ}C$. Throughout repeated densification process, the density of the material reached $1.903g/cm^3$. After machining 4D C/C composites, the nozzle surface was coated by a SiC layer by pack-cementation method to improve oxidation resistance. Erosion characteristics of SiC-coated C/C composites were measured as function of the ratio of oxygen to fuel. The morphological change of the composites after combustion test was investigated using SEM and erosion mechanism also was discussed.

An Experimental Study on Flexural Strength of SC Composite Beams Enforced by Unbonded Post Tension (비부착 포스트텐션 SC합성보의 휨내력에 관한 실험적 연구)

  • Kim, Heui Cheol;Ahn, Hyung Joon;Ryu, Soo Hyun
    • Journal of Korean Society of Steel Construction
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    • v.21 no.2
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    • pp.135-144
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    • 2009
  • This study aims to suggest an appropriate flexural reinforcement technique by evaluating the reinforcement capacity of specimens that underwent flexural reinforcement according to the post-tension method with the anchoring position of an unbonded tension member on the conventional SC composite beam and the applied tension level as variables. For the experiment, up to a predetermined yield load was applied to each type of specimen and then, unbounded post-tensioning was additionally conducted to examine its reinforcement capacity. The analysis of the said experiment showed that the post-reinforced SC composite beam was characterized by significantly improved yield stress and initial stiffness, compared with the pre-reinforced one and the experimental measurements/theoretical values of maximum stress ranged from 0.95 to 1.13 following reinforcement. There was little or no change depending on the maximum stress and tension in the specimen (D160, Class 240) whose neutral axis and upper part had anchoring devices mounted prior to reinforcement. Rather, the ductility decreased with the increasing tension. On the contrary, in the case of the other specimen (Class D120) whose neutral axis had anchoring devices mounted after reinforcement, both the maximum stress and ductility increased with increasing tension, which indicates that the latter tension reinforcement was reasonably appropriate and effective for the neutral axis reinforcement.

Stability of Saturation Controllers for the Active Vibration Control of Linear Structures (선형 구조물의 능동 진동 제어를 위한 포화 제어기의 안정성)

  • Moon, Seok-Jun;Lim, Chae-Wook;Huh, Young-Chul
    • Journal of the Earthquake Engineering Society of Korea
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    • v.10 no.6 s.52
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    • pp.93-102
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    • 2006
  • Control input's saturation of active control devices for large structures under large external disturbances are often occurred. It is more difficult to obtain the exact values of mass and stiffness as structures are higher. The modelling errors between mathematical models and real structures must be also included as parameter uncertainties. Therefore, in active vibration control of civil engineering structures like buildings and bridges, the robust saturation controller design method considering both control input's saturation and parameter uncertainties of system is needed. In this paper, stabilities of linear optimal controller LQR, modified bang-bang controller, saturated sliding mode controller, and robust saturation controller among various controllers which have been studied and applied to active vibration control of buildings are investigated. Especially, unstable phenomena of the LQR, the modified bang-bang controller and the saturated sliding mode controller when the control input is saturated or parameter uncertainties exist are presented to show the necessity of the robust saturation controller. The robust stability of the robust saturation controller are shown through a numerical example of a 2DOF linear vibrating system and an experimental test of the two-story structure with an active mass damper (AMD).

The Deformation Behavior of Anchored Retention Walls installed in Cut Slope (절개사면에 설치된 앵커지지 합벽식 옹벽의 변형거동)

  • Yun, Jung-Mann;Song, Young-Suk
    • The Journal of Engineering Geology
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    • v.19 no.4
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    • pp.475-482
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    • 2009
  • The behavior of earth retention wall installed in cut slope is different from the behavior of retention wall applied in urban excavation. In order to establish the design method of anchored retention walls in cut slope, the behavior of anchored retention wall can be investigated and checked in detail. In this study, the behavior of anchored retention wall was investigated by instrumentation installed in cut slope for an apartment construction stabilized by a row of piles. The horizontal displacement of anchored retention wall was larger than the displacement of slope soil behind the wall at the early stage of excavation. As the excavation depth became deeper, the horizontal displacement of slope soil was larger than the displacement of anchored retention wall. It means that the horizontal displacement of anchored retention wall due to excavation is restrained by soldier pile stiffness and jacking force of anchor. Jacking force of anchor was mainly influenced in the horizontal displacement of anchored retention wall. The displacements of anchored retention wall and slope soil were affected mainly by an rainfall infiltrated from the ground surface. Meanwhile, the horizontal displacement of anchored retention wall with slope backside was about 2-6 times larger than the displacement of anchored retention wall with horizontal backside of excavation.

Estimation of Coefficient of Earth Pressure At Rest During SCP Installation by Drained Triaxial Compression Test (배수삼축압축시험을 통한 SCP 시공과정 중 정지토압계수 평가)

  • Kwon, Youngcheul
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.11
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    • pp.93-101
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    • 2012
  • SCP is a construction method that maximizes the effects of ground improvement by creating sand piles, which are formed by the compaction within soft ground. SCP is mainly used for consolidation and drain effects in clayey soils, and as a liquefaction countermeasure through effects such as compaction in loose sandy soils. In the design of SCP, if the sand piles with high stiffness are not taken into account, it can become a design that overly considered safety, and increased construction costs are highly likely to cause economic disadvantages. The changes in stress conditions and compaction mechanisms in the subsurface have been identified to a certain extent by study findings to date. However, the studies that considered SCP and in-situ ground as composite ground are fairly limited, and therefore, those studies have not achieved enough results to fully explain the relevant topics. In this study, the ground improved by SCP was regarded as the composite ground that consists of SCP and in-situ ground. Moreover, employing a CID test, this study examined the changes in the stress conditions of in-situ ground according to the installation of SCP through the relations between $K_0$ and SCP replacement ratio. At the same, whether the SCP installation procedure can be recreated in a laboratory was examined using a cyclic triaxial test. According to the test results, the changes in the stress conditions of the original ground occurred most largely in an initial stage of SCP installation, and after a certain time point, the vibration for SCP installation did not have a great influence on the changes in the stress conditions of the ground. Moreover, in order to recreate the behaviors of in-suit ground according to SCP in a laboratory, cyclic loading, which corresponds to casing vibration, was concluded to be essentially required.

Stability Analysis of a Haptic System with a Human Impedance model using the Routh-Hurwitz Criterion (루드-후르비쯔 (Routh-Hurwitz) 안정성 판별법을 이용한 인간의 임피던스가 포함된 햅틱 시스템의 안정성 분석)

  • Lee, Kyungno
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.4
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    • pp.1813-1818
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    • 2014
  • This paper presents the stability analysis of the haptic system including a human impedance using the Routh-Hurwitz criterion. The reflective force is computed from a virtual spring model and is transferred to a human operator using the first-order-hold method. The stability boundary conditions are induced and the relation among a virtual spring ($K_w$), the mass ($M_h$), the damping ($B_h$) and the stiffness ($K_h$) of a human impedance is analyzed. Hence the stability boundary of the virtual spring ($K_w$) is proposed as $K_w{\leq}54413{\sqrt{(M_h+M_d)(B_h+B_d)}}-0.486K_h$ when the sampling time is 1 ms. The average relative error is about 0.5% when the mathematical analysis results are compared with the results of the stability boundary model.

Investigation of Stiffness Characteristics of Subgrade Soils under Tracks Based on Stress and Strain Levels (응력 및 변형률 수준을 고려한 궤도 흙노반의 변형계수 특성 분석)

  • Lim, Yujin;Kim, DaeSung;Cho, Hojin;Sagong, Myoung
    • Journal of the Korean Society for Railway
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    • v.16 no.5
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    • pp.386-393
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    • 2013
  • In this study, the so-called repeated plate load bearing test (RPBT) used to get $E_{v2}$ values in order to check the degree of compaction of subgrade, and to get design parameters for determining the thickness of the trackbed foundation, is investigated. The test procedure of the RPBT method is scrutinized in detail. $E_{v2}$ values obtained from the field were verified in order to check the reliability of the test data. The $E_{v2}$ values obtained from high-speed rail construction sites were compared to converted modulus values obtained from resonant column (RC) test results. For these tests, medium-size samples composed of the same soils from the field were used after analyzing stress and strain levels existing in the soil below the repeated loading plates. Finite element analyses, using the PLAXIS and ABAQUS programs, were performed in order to investigate the impact of the strain influence coefficient. This was done by getting newly computed $I_z$ to get the precise strain level predicted on the subgrade surface in the full track structure; under wheel loading. It was verified that it is necessary to use precise loading steps to construct nonlinear load-settlement curves from RPBT in order to get correct $E_{v2}$ values at the proper strain levels.

Structural Performance and Usability of Void Slab Established in T-deck Plate (T형 데크 플레이트 중공형 슬래브의 구조성능 및 사용성능)

  • Hong, Eun-Ae;Chung, Lan;Paik, In-Kwan;Yun, Sung-Ho;Cho, Seung-Ho
    • Journal of the Korea Concrete Institute
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    • v.24 no.6
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    • pp.677-684
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    • 2012
  • In recent years, extension of life span of buildings is becoming an important issue in our society. To improve the life span of buildings, rhamen structure construction and long-spanned structures are advantageous. And in order to achieve this goal, structural elements of buildings must be light and slender. As an alternative method, general porous slabs are used frequently domestically and internationally. But the study on the porous slabs using T-deck plate and assembly of light weight precast construction is insufficient at present. In this study, flexural and fatigue tests were performed on six specimens to verify structural performance and serviceability. The main parameters of the specimens were light weight and T-deck plate construction possibility as well as slab thickness. The test results indicated that the strength of porous slabs using T-deck plate and assembly of light weight were much better than general RC slabs and porous slabs without T-deck plate. And stiffness was much better than that of other tested slabs.