• Textile Coloration and Finishing
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• v.12 no.2
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• pp.89-95
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• 2000

Effect of twist-setting time, temperature and cylinder layer for the physical properties of the twist yarn were investigated by separated 9 layer from yarn cylinder. Obtained results were as follow. Shrinkage of the yarn in middle layer shows high value with heat-permeation and in inner's shows low value because of cylinder hardness. And then yarn thermal shrinkage in outer layers shows more or less high value because twist yarn in the outer layer sets more faster. Concerning to the difference on the yam physical properties among cylinder layers, the changes on physical properties shows significant differences from the 7th layer to the last one. Linear density, T.P.M and initial modulus decreases but snarl index increases.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.327-329
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• 2008

We have studied the optically compensated splay (OCS) mode using reactive mesogen monomer to reduce critical voltage, setting voltage and phase transition time from initial bend to splay state. The high pretilt angle from vertical alignment was formed through the polymerization of UV curable RM monomer at the surfaces. In this way, orientation of the LC with OCS can be achieved without setting voltage.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.218-225
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• 2023

In this study, we examine the feasibility of using chlorine in clinker as an early-strength cement by the effect of accelerating the cement hydration reaction of chlorine. Clinker with a chlorine content of 200-1,000 ppm was prepared using actual cement kilns, and 46 cement samples were prepared by adding gypsum and admixtures(GGBFs and limestone). We measured consistency, setting, 1-28 days compressive strength and analyzed them statistically. Test results indicated that an increase of the chlorine content resulted in shortening of initial and final setting time and the improvement of 1 day compressive strength. But the 28 days compressive strength was decreased. Specifically, when the chlorine content was increased from 230 to 965 ppm, the 1 day compressive strength increased up to 4.6 MPa, improvement effect was superior to that of increasing Blaine in the range of 3,400-3,970 cm²/g.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1133-1138
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• 2012

In the paper, design of nonlinear sliding surfaces which are based on optimal control is studied, The state trajectory by the input of optimal control was obtained by Frobenius theorem and matrix decomposition method, was set the nonlinear sliding surfaces of the system. The states is maintained to sliding surfaces from initial states. As the result, robustness of the system can be guaranteed throughout an entire response of the system starting form the initial time instance, the uncertainty and external disturbance that can occur during the reaching time is removed, the problem of large control input was solved, and setting the sliding surfaces optimal path was able to reduce the tracking time. The validity of the proposed control scheme is shown in computer simulation for inverted pendulum.

• Computers and Concrete
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• v.17 no.3
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• pp.423-433
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• 2016

After the industrial of steelmaking by-products are processed properly, they can be used in civil engineering, not only as a substitute for natural resources and to reduce costs, but also to provide environmental protection. This study used different amounts (10%, 20%, 30%, 40%,and 50%) of desulphurization slag to replace natural fine aggregates in ready-mixed soil materials, and tested the physical and fresh properties (slump, slump flow, tube flow, initial setting time, and bleeding) and hardened properties (compressive strength, ball drop, ultrasonic pulse velocity) of the materials. The variations between the performances of the materials with different mix proportions were discussed. When desulphurization slag is used in RMSM, the workability can be enhanced obviously significantly. When the replacement of desulphurization slag is 50%, the slump flow is increased by 110mm compared with the control group, and the initial setting time increases as the replacement increases, because of bleeding. When the replacement is 10% and 20%, the compressive strength at various ages is higher than that of the control group. When the replacement is 10%, the compressive strength at 7 days is higher than that of the control group by 60%, and the ultrasonic pulse velocity is proportional to the compressive strength, which increases with age and decrease as the replacement increases. An appropriate replacement can effectively accelerate construction, and allow projects to be finished ahead of schedule; therefore, an appropriate replacement, is applicable for ready-mixed soil materials.

• Journal of the Korean Ceramic Society
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• v.39 no.10
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• pp.943-947
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• 2002

In order to examine the possibility of incineration of inderstrial by-product and wastes which contains a large percentage of chlorine by the cement kiln, measured heat of hydration, setting time, flow, change of length, compressive strength of OPC by the amount of KCl. The result was that a shorter setting time, a lower flow, a increasing the degree of initial shrinkage, a increasing of compressive strength before 3 days and decrease after 7 days by the induction period is shorter as promote the hydration with KCl.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.6
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• pp.74-82
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• 1996

In this study, the characteristics of antiwashout underwater concrete according to the using types of admixture were experimentally investigated. Especially, the comparison on the performance of seven types(CO-A, B, C, D, E, F, G) of the manufactured admixtures was carried out in the same mixing condition and proportions. Based on the results of experiments, the conclusions were summarized as follows : (1) The slump flow on most of specimens except by CO-F type were progressed very well. (2) In most of products, the measured values of suspensions, pH's and air contents were lower than their reference values. However, CO-B, CO-F and CO-G types exceeded the reference ones in suspension and pH. (3) The time lags between initial and final setting were about three hours in most of tests, however, the maximum difference of total setting time was ten hours in comparing with the admixture types. The unit weights were mostly lower than $2300kg/m^3$ and the compressive strengths cured by salt water were about 80% of the ones by fresh water. (4) Finally, in spite of some problems, most of the manufactured admixtures may be performed well their functions in antiwashout under-water concrete if the using quantities are properly controlled by the site experiments.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.424-425
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• 2007

We have studied the optically compensated splay mode using reactive mesogen (RM) monomer to reduce setting voltage and phase transition time from initial bend to splay state. When the OCS cell has low pretilt angle close to $45^{\circ}C$, OCS state can be formed easily. The low pretilt angle was formed through the polymerization of UV curable reactive RM monomer at the surfaces. In this way, reorientation of the LC is well defined and thus the device shows better performances in setting voltage and phase transition time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.3
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• pp.984-996
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• 2014

In this paper, optimal sensing time allocation for adaptive multiband spectrum sensing-transmission procedure is investigated. The sensing procedure consists of an exploration phase and a detection phase. We first formulate an optimization problem to maximize the throughput by designing not only the overall sensing time, but also the sensing time for every stage in the exploration and detection phases, while keeping the miss detection probability for each channel under a pre-defined threshold. Then, we transform the initial non-convex optimization problem into a convex bilevel optimization problem to make it mathematically tractable. Simulation results show that the optimized sensing time setting in this paper can provide a significant performance gain over the previous studies.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.906-908
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• 1999

In this paper, new sliding mode surfaces are proposed by defining novel virtual states. These sliding surfaces have nominal dynamics of an original system and makes it possible that the Sliding Mode Control(SMC) technique is used with the various types of controllers. Its design is based on the augmented system whose dynamics have m-th higher order than those of the original system where m is the number of inputs. The reaching phase is removed by setting the initial virtual states which makes the initial switching functions equal to zero.