• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2359-2368
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• 2013

In this paper, an IRD (internal read data) circuit preventing the reentry into the read mode while keeping the read-out DOUT datum at power-up even if noise such as glitches occurs at signal ports such as an input signal port RD (read) when a power IC is on, is proposed. Also, a pulsed WL (word line) driving method is used to prevent a DC current of several tens of micro amperes from flowing into the read transistor of a differential paired eFuse OTP cell. Thus, reliability is secured by preventing non-blown eFuse links from being blown by the EM (electro-migration). Furthermore, a compared output between a programmed datum and a read-out datum is outputted to the PFb (pass fail bar) pin while performing a sensing margin test with a variable pull-up load in consideration of resistance variation of a programmed eFuse in the program-verify-read mode. The layout size of the 8-bit eFuse OTP IP with a $0.18{\mu}m$ process is $189.625{\mu}m{\times}138.850{\mu}m(=0.0263mm^2)$.

• International Journal of Concrete Structures and Materials
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• v.18 no.1E
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• pp.29-34
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• 2006

Elastic modulus, tensile and bond capacities are important factors for developing an effective reinforcing action of a flexural member as a reinforcing material for concrete structures. Reinforcement must have enough bond capacity to prevent the relative slip between concrete and reinforcement. This paper presents an experimental study to clarify the bond capacity of prestressed carbon fiber reinforced polymer(CFRP) rod manufactured by an automatic assembly robot. The bond characteristics of CFRP rods with different pitch of helical wrapping were analyzed experimentally. As the result, all types of CFRP rods show a high initial stiffness and good ductility. The mechanical properties of helical wrapping of the CFRP rods have an important effect on the bond of these rods to concrete after the bond stress reached the yield point. The stress-slip relationship analyzed from the pull-out test of embedded cables within concrete was linear up to maximum bond capacity. The deformation within the range of maximum force seems very low and was reached after approximately 1 mm. The average bond capacity of CF20, CF30 and CF40 was about 12.06 MPa, 12.68 MPa and 12.30 MPa, respectively. It was found that helical wrapping was sufficient to yield bond strengths comparable to that of steel bars.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.320-329
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• 2005

The use of diverse methods for the retaining system has been continuously increased in order to maintain the stability during excavation. However, ground anchor system occasionally may have the restriction in urban excavation sites nearby the existing structures because of space limitation. In this case, soil nailing system with relatively short length of nails could be efficiently useful as an alternative method. The general soil nailing support system, however, may result in excessive deformations particularly in excavating the zone of weak soils or nearby the existing structures. Therefore, applying the pretension force to the soil nails then could play important roles to reduce deformations mainly in an upper part of the nailed-soil excavation system as well as to improve the local slope stability. In this study, a newly modified soil nailing technology named as the PSN(Pretention Soil Nailing) is developed to reduce both facing displacements and ground surface settlements during top-down excavation process as well as to increase the global slope stability. Up to now, the PSN system has been investigated mainly focusing on an establishment of the design procedure. In the present study, the field tests including pull-out tests were fulfilled to investigate the behavior of characteristics for PSN system. All results of tests were also analyzed to provide a fundamental and efficient design.

• Journal of the Korean Geotechnical Society
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• v.28 no.1
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• pp.5-15
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• 2012

This paper presents the results of an investigation into the pull-out characteristics of screw anchor piles for use in braced excavation and cut-slope. A series of reduced-scale model tests were performed on model screw anchor piles with different geometric characteristics such as screw size and pitch length. The results indicated that the pullout resistance increases with decreasing the pitch length for a given screw size. It was also observed that the pullout capacity of a screw anchor pile increases with the screw size up to a certain size beyond which the increase becomes minimal. The results are presented in such a way that the pullout characteristics of screw piles with different screw geometric characteristics can be identified. Practical implications of the findings are discussed.

• Journal of Adhesion and Interface
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• v.13 no.1
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• pp.9-16
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• 2012

In order to describe external effects on the behavior of the adhesive tape, the semi-rigid body cylinder chain model for adhesive tape has been proposed as follows. Firstly the behavior of the tape is in detail investigated while it's being pulled off from the plate, and subsequently a relevant phenomenological model is designed. Then all the contributors affecting the force to peel out the tape from plate (hereafter, the pull out force) are clearly defined and their sensitivity analyses are made to set up the experimental reference condition, under which the angular dependence of the pull out force is measured in every $10^{\circ}$. The experimental data turn out to be in good agreement with the theoretical ones by our model within the measurement error, and the effects due to other factors are proved to be well explained from the phenomenological viewpoint. From these results, the concept of this study might be expected to be very useful for the test and evaluation of PSA types of adhesive tape.

• Steel and Composite Structures
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• v.33 no.1
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• pp.19-36
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• 2019

Cyclic behaviour of composite (steel-concrete) plate shear walls (CPSW) with variable column flexural stiffness is experimentally and numerically investigated. The investigation included design, fabrication and testing of three pairs of one-bay one-storey CPSW specimens. The reference specimen pair was designed in way that its column flexural stiffness corresponds to the value required by the design codes, while within the other two specimen pairs column flexural stiffness was reduced by 18% and 36%, respectively. Specimens were subjected to quasi-static cyclic tests. Obtained results indicate that column flexural stiffness reduction in CPSW does not have negative impact on the overall behaviour allowing for satisfactory performance for up to 4% storey drift ratio while also enabling inelastic buckling of the infill steel plate. Additionally, in comparison to similar steel plate shear wall (SPSW) specimens, column "pull-in" deformations are less pronounced within CPSW specimens. Therefore, the results indicate that prescribed minimal column flexural stiffness value used for CPSW might be conservative, and can additionally be reduced when compared to the prescribed value for SPSWs. Furthermore, finite element (FE) pushover simulations were conducted using shell and solid elements. Such FE models can adequately simulate cyclic behaviour of CPSW and as such could be further used for numerical parametric analyses. It is necessary to mention that the implemented pushover FE models were not able to adequately reproduce column "pull-in" deformation and that further development of FE simulations is required where cyclic loading of the shear walls needs to be simulated.

• Journal of the Korean Arthroscopy Society
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• v.6 no.1
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• pp.31-36
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• 2002

Objective : The purpose of this study was to evaluate the clinical and radiological results after treatment of old ACL(anterior cruciate ligament) avulsion fracture of tibia. Materials and Method : 11 cases who were followed up at least 2 years after treatment in chronic ACL avulsion fracture of tibia were included in this study. The average age of patients was 26(9-66) years and the mean period of follow up was 53(24-131) months. After evaluation of the lesion and treatment of associated lesion under arthroscope, open reduction and internal fixation or fragment removal was performed. Pull-out suture was performed in 8 cases, screw fixation in 2 cases. Results : The Lysholm knee score was 64.3 in average preoperatively and improved to 96.2 average at follow up. On the Lachman test, there were mild(+) instabilities in 7 cases, moderate(++) in 4 cases. On the postoperative Lachman test, there were no instabilities in 9 cases, mild(+) instabilities in only 2 cases. According to Meyers and Mckeever's evaluation protocol, 9 cases $(81.8\%)$ were excellent, 2 case $(18.2\%)$, good. On preoperative instrumented anterior laxity test with $Telos^{\circledR}$, side to side difference in 201b was 7.8(10-4) min in average and 2.1(6-0) mm in average at follow-up. Conclusion : In chronic ACL avulsion fracture, it is thought that combination of arthroscopic evaluation of associated injury and open reduction and fixation and fragment removal can bring about satisfactory results.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.171-178
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• 2008

This paper is concerned with the development of a measurement system using field measuring device which will give the membrane stress of the membrane structures. Up to this point, several techniques on measurement of membrane stresses has been proposed and some have been used in the fields, but accuracy of the measured stresses to be far from reliable one. Such situation has not been changed until recent days, we do not have the measurement device on which we can depend. On top of that, due to the different properties in cross directions for material of the membrane, the stress in the warp direction is different from that in the fill one. A new method is proposed to measured membrane stresses in two different direction separately, where instead of membrane stresses directly, an external force perpendicular to the membrane to be applied. A portable device can measure the applied force and the displacement. A special testing bed to be fabricated to accommodate $50cm{\times}50$ manbrane specimen which can apply 5 ton load in two orthogonal direction. A special device using push-pull gage was developed. To measure the membrane stresses in warp and fill direction separately, a different length of the tips are used. The measuring device which can called tension meter, can be calibrated on the testing bed, and optimized the length and shape of tip.

• Explosives and Blasting
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• v.17 no.4
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• pp.18-31
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• 1999

The explosive forming has been used for many year to expand tubes into tubesheets. this process has demonstrated ability to direct carefully the energy of an explosive to expand tubes into tubesheet holes without damaging the tubesheet and without causing the excessive cold work at the tube I.D. that is normally associated with mechanical expansion. The success of explosive tube expansion provided the background for the development of the explosive tube plug. The main results are as follows : (1) The optimum explosives and explosive qualities are PETN, RDX, HMS and about 18~31gr/ft of explosive plugging in nuclear steam generator. (2) Explosive plugging's thickness is 0.9~1.8mm. If groove of 0.4 mm formed in plug outside, For the hydraulic leakage is go up, explosive plugging of formed groove are applicate tube and tubrplate. (3) Sheath is designed on the polyethylene of low density, In thermal impact test of the $430^\circ{C}$, hydraulic leakage is $300kg/cm^2$. (4) About 10~60mm oxide inclusions are existed on the space of explosive plug and tube protect to the leakage.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.219-223
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• 2009

This paper is the result of investigation of ONO PPSM(ONO PORTABLE SLIP METER) by way of experiment to see the validity as a slip meter, ONO PPSM is a portable slip meter which was made up for the weak points of O-Y PSM(ONO-YOSHIOKA PULL SLIP METER) which takes an accurate measurement of the slip resistance but very heavy and hard to operate. In order to know the stability of the measurement result of ONO PPSM, we measured the slip resistance against 4 different kind of floor materials. As a result of this, we found out that the coefficient of variability of CSR' is less than 0.05. Also, we verified the relation between CSR' and CSR. more specifically by doing the slip test against 7 different kinds of inorganic matter floor materials. We increased the usability of ONO PPSM as a slip meter by suggesting the method of sharing the evaluation index of slip of CSR' and C.S.R.