• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2006.05a
• /
• pp.19-22
• /
• 2006

The quantity of Recycled concrete powder is increased, because it hal been ever so often crushing for production of a good quality recycled aggregates This Study is on the Development of Concrete-Product by Using Recycled Concrete Powder and alto for know performance of concrete-producted having low water contents and it is to know for all of performance of concrete-producted having low water contents The conclusions of this study are following. The use of replacement cement is not effective, because it has strengh of less than 10MPa But It is possible to develop high strength concrete-producted having 39MPa above compressive strength by using recycled concrete powder. Because strength enhancement effects by recycled concrete powder are responsible to optimum grading. The conclusions of this study are following. The use of replacement cement is not effective, because it has strengh of less than 10MPa. It is possible to develop high strength concrete-producted having 39MPa above compressive strength by using recycled concrete powder. Because strength enhancement effects by recycled concrete powder are responsible to optimum grading.

• Smart Structures and Systems
• /
• v.17 no.4
• /
• pp.541-557
• /
• 2016

Prefabricated bridge substructures provide new possibility for designers in terms of efficiency of creativity, fast construction, geometry control and cost. Even though prefabricated bridge columns are widely adopted as a substructure system in the bridge construction project recently, lack of deeper understanding of the seismic behavior of prefabricated bridge substructures cause much concern on their performance in high seismic zones. In this paper, experimental research works are presented to verify enhanced design concepts of prefabricated bridge piers. Integration of precast segments was done with continuity of axial prestressing tendons and mild reinforcing bars throughout the construction joints. Cyclic tests were conducted to investigate the effects of the design parameters on seismic performance. An analytical method for moment-curvature analysis of prefabricated bridge columns is conducted in this study. The method is validated through comparison with experimental results and the fiber model analysis. A parametric study is conducted to observe the seismic behavior of prefabricated bridge columns using the analytical study based on strain compatibility method. The effects of continuity of axial steel and tendon, and initial prestressing level on the load-displacement response characteristics, i.e., the strain of axial mild steels and posttensioned tendon at fracture and concrete crushing strain at the extreme compression fiber are investigated. The analytical study shows the layout of axial mild steels and posttensioned tendons in this experiment is the optimized arrangement for seismic performance.

• International Journal of Concrete Structures and Materials
• /
• v.11 no.1
• /
• pp.99-113
• /
• 2017

The effects of different lightweight functional fillers on the properties of cement-based composites are investigated in this study. The fillers include fly ash cenospheres (FACs) and glass micro-spheres (GMS15 and GMS38) in various proportions. The developed composites were tested for compressive, flexural and tensile strengths at 10 and 28-day ages. The results indicated that both FACs and GMS38 are excellent candidates for producing strong lightweight composites. However, incorporation of GMS15 resulted in much lower specific strength values (only up to $13.64kPa/kg\;m^3$) due to its thinner shell thickness and lower isostatic crushing strength value (2.07 MPa). Microstructural analyses further revealed that GMS38 and GMS15 were better suited for thermal insulating applications. However, higher weight fraction of the fillers in composites leads to increased porosity which might be detrimental to their strength development.

• Steel and Composite Structures
• /
• v.32 no.1
• /
• pp.59-66
• /
• 2019

Hollow steel-reinforced concrete-filled GFRP tubular member is a new kind of composite members. Firstly set the mold in the GFRP tube (non-bearing component), then set the longitudinal reinforcements with stirrups (steel reinforcement cage) between the GFRP tube and the mold, and filled the concrete between them. Through the axial compression test of the hollow steel-reinforced concrete-filled GFRP tubular member, the working mechanism and failure modes of composite members were obtained. Based on the experiment, when the load reached the ranges of $55-70%P_u$ ($P_u-ultimate$ load), white cracks appeared on the surface of the GFRP tubes of specimens. At that time, the confinement effects of the GFRP tubes on core concrete were obvious. Keep loading, the ranges of white cracks were expanding, and the confinement effects increased proportionally. In addition, the damages of specimens, which were accompanied with great noise, were marked by fiber breaking and resin cracking on the surface of GFRP tubes, also accompanied with concrete crushing. The bearing capacity of the axially compressed components increased with the increase of reinforcement ratio, and decreased with the increase of hollow ratio. When the reinforcement ratio was increased from 0 to 4.30%, the bearing capacity was increased by about 23%. When the diameter of hollow part was decreased from 55mm to 0, the bearing capacity was increased by about 32%.

• Steel and Composite Structures
• /
• v.32 no.5
• /
• pp.657-670
• /
• 2019

This paper proposes a one-dimensional fiber beam element model taking account of materially non-linear behavior, benefiting the highly efficient elastic-plastic analysis of girders with shear-lag effects. Based on the displacement-based fiber beam-column element, two additional degrees of freedom (DOFs) are added into the proposed model to consider the shear-lag warping deformations of the slabs. The new finite element (FE) formulations of the tangent stiffness matrix and resisting force vector are deduced with the variational principle of the minimum potential energy. Then the proposed element is implemented in the OpenSees computational framework as a newly developed element, and the full Newton iteration method is adopted for an iterative solution. The typical materially non-linear behaviors, including the cracking and crushing of concrete, as well as the plasticity of the reinforcement and steel girder, are all considered in the model. The proposed model is applied to several test cases under elastic or plastic loading states and compared with the solutions of theoretical models, tests, and shell/solid refined FE models. The results of these comparisons indicate the accuracy and applicability of the proposed model for the analysis of both concrete box girders and steel-concrete composite girders, under either elastic or plastic states.

• The Journal of Korean Medicine
• /
• v.31 no.1
• /
• pp.93-111
• /
• 2010

Objectives: The present study was performed to evaluate the potential effects of Bupleuri radix (SH) on regenerative activities in the peripheral sciatic nerve after crushing injury in rats. Methods: Axonal regeneration after crush injury in rats was analyzed by immunofluorescence staining using anti-NF-200 antibody and retrograde tracing of DiI-axons. Changes in protein levels in the sciatic nerve axons and DRG tissue were analyzed by Western blot analysis and immunofluorescence staining. Effects of SH extract treatment on neurite outgrowth was examined by immunofluorescence staining for cultured DRG neurons. Results: Major findings on the effects of SH extract treatment on axonal regeneration are summarized as follows. 1. SH-mediated enhancement in axonal regeneration was identified by immuno- fluorescence straining of NF-200 protein and retrograde tracing of DiI-labeled axons. 2. Axonal GAP-43 protein levels were upregulated by SH not only in the injured axons but also in the DRG sensory neurons corresponding to sciatic sensory axons. 3. Phospho-Erk1/2 protein levels were increased in both injured axonal area and DRG sensory neurons by SH. Phospho-Erk1/2 was also found in non-neuronal cells in the injured axons. 4. SH elevated levels of Cdc2 protein produced in Schwann cells in the distal portions of injured sciatic nerves. 5. The neurite outgrowth of DRG sensory neurons in culture was augmented by SH, and these changes were positively associated with GAP-43 production levels in the DRG neurons. Conclusions: These data suggest that SH extract improves the regenerative responses of injured peripheral neurons, and thus may be useful for understanding molecular basis for the development of therapeutic strategies.

• Journal of Haehwa Medicine
• /
• v.14 no.1
• /
• pp.15-22
• /
• 2005

Source : sources used by Qianghuo is Ostericum koreanum Maximowicz, Notopterygium incisum Ting and Notopterygium forbesii Boissier etc. in Korea and China. And we cirulate a Qianghuo dividing Nanqianghuo and Beiqianghuo. Thought source of Korea Qianghuo is different from china's we use a same name. And source of Beiqianghuo has not made clear yet. According to research accomplished 2002, we have to use Nanqianghuo producted at Jinbu in aspect of aspect. but, Beiqianghuo the outside form of Beiqianghuo similar to china so we think that we have to more make clear source of domestic Qianghuo, verify a source Beiqianghuo and re-establish about effects and functions of domestic Qianghuos. Culture : A term of culture is an nearly one year. so to product Qianghuo of good quality, we must plant directly in autumn or raise seedlings and transplant in spring. Processing : To protect turning to brown, Qianghuo are cirulate mostly as the original form without washing in water, To proteet crushing of Qianghuo when we cut off, Qianghuo were cut off after being soaked in water or steamed by heat. So when we wash and cut off, it has to be made processes which have no decreases of medical effects and be suggested a proper index which verify a medical effects. In summury, after harvesting Qianghuo the first washing $\rightarrow$ the first dry $\rightarrow$ selection $\rightarrow$ the second washing $\rightarrow$ the second dry $\rightarrow$ selection $\rightarrow$ cutting off $\rightarrow$ the third dry.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2004.05a
• /
• pp.71-74
• /
• 2004

Recently, with the wide shortage of natural sand resources, it has been increasingly used the crushed sand. rushed sand is made by the process of crushing the rocks artificially, which has different particle properties compared with that of natural sand. Because such different panicle properties of crushed sand results in an undesirable effects of concrete. improvement technology for crushed sand particle properties like grain shape and fine particle needed during the manufacturing process. In this paper, improvement technology of grain shape and fine particle is reported. According to test results, adequate investment for manufacturing facilities like impact crusher and abrasion test machine is required to meet the advanced grain shape and grading of crushed sand. Based on the investigation of test result, mixing of natural land and crushed sand with given proportion can achieve the improvement of grain shape. For improving excessive fine panicle contents. current manufacturing system also can enhance the existing technology for fine particle without additional investment. It can be concluded that adequate investment and research can improve the quality of crushed sand.

• Korean Journal of Pharmacognosy
• /
• v.37 no.2 s.145
• /
• pp.97-102
• /
• 2006

Garlic(Allium sativum Linn) is widely used as a common condiment for a variety of foods and beverages. It has been well known that fresh garlic and garlic supplement of commercial preparations have various therapeutic properties including antimicrobial activity, antiplatelet aggregation, antihypertension, and cholesterol-lowering effects, which contribute to its increasing uses for an alternative medicine. Allicin(diallyl thiosulfinate), the major bioactive components of garlic, is formed by alliinase cleavage of the naturally occurring alliin upon crushing or mincing of garlic, and is the progenitor of a number of other products, such as diallyl disulfide. CYP3A4, heme-containing monooxygenase, is a key enzyme responsible for drug metabolism. Therefor, in the present study, we isolated and examined the compounds with CYP3A4-inhibiting activities from garlic. Among EtOAc extracts of garlic, we found that N-p-coumaroyltyramine and N-feruloyltyramine showed remarkable CYP3A4-inhibiting activities, compared to diallyl disulfide. Structures of the isolated active compounds were established by chemical and spectroscopic means.

• Journal of Korean Society of Steel Construction
• /
• v.15 no.1
• /
• pp.33-40
• /
• 2003

There are two basic concepts about concerning the buckling analysis of a buried pipe. One concept considers the soil around the pipe asn elastic continuum mediaum. The other concept holds that the pipe is sup ported by an elastic spring, which replaces the effects of the surrounding soil (the Winkler model). Theise buckling analysis is based on plane analysis, without considering the corrugation effect and the length effect. This paper thus presents a parametric study using the Finite Element Method (FEM) for the Winker model and proposes a buckling strength formula after examining a 3D analysis considering the corrugation effect and the length effect, thatwhichhelp in estimating the critical buckling strength of such CSP