• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.29 no.3
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• pp.214-219
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• 1993

Counter balance valve is used as one part of hydraulic motor brake system. The function of this valve is to protect over-run or free falling of inertia load. But occasionally the brake system with counter balance valve makes some undesirable problems such as pressure surges or vibrations. These problems may hurt system safety and driver's conformability. Nevertheless, studies on dynamic characteristics of hydraulic system including counter balance valve are very rare, so further accumulation of research results are required. In this study, for the purpose of easy estimation about dynamic characteristics of hydraulic system including counter balance valve, precise formulation describing fluid dynamics and valve dynamics under various boundary conditions were made. The equations obtained in the preceding process include some parameters that must be got experimentally. Flow coefficients of valve and choke are the most significant ones among the parameters. So these parameters are obtained experimentally in this study, and experimental equations obtained from the experimental data were used for numerical calculation. The equations were analysed by numerical integration using Runge-Kutta method, because the equations contain various nonlinear terms. From the numerical analysis, it was verified that the dynamic response of counter balance valve and pressure variation at each elements can be estimated very easily. So the analysing method developed in this study enabled very easy estimating the relation between the performances of counter balance valve and various physical parameters related to the valve. Conclusively, it is said that the results obtained in this study can be used very usefully to develop a new type counter balance valve or to apply the valve to actual hydraulic system for various industrial equipments.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.135-136
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• 2012

The purpose of this study is to analysis of counter strategy of greenhouse gas·energy target management system for the construction firm. For this purpose, the greenhouse gas·energy target management system of other industries was investigated. The selection possibility that is construction firm to be managed company was analyzed. In addition, status of counter strategy on the greenhouse gas·energy target management system were investigated and analyzed about 5 domestic major construction firm via questionnaire and interview. As a result, the counter strategy by organization and annual for the greenhouse gas·energy target management system was drawn.

• Design & Manufacturing
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• v.6 no.2
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• pp.54-58
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• 2012

A counter shaft gear is an important part in the transmission system of vehicle. Its shape is relatively complicated and should meets high strength. Traditionally it has been manufactured as follows; the counter shaft gear has consisted of a clutch and helical body with teeth which are forged and machined for teeth respectively and then attached by frictional welding. In this study, a new hot forging process was proposed and designed so that the counter shaft gear is formed as one body without divide it into two parts. Furthermore, the precision forging process has been developed for the clutch teeth without additional grinding.

• 한국연소학회:학술대회논문집
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• 2000.05a
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• pp.105-116
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• 2000

An Experimental study was conducted on spray combustion using dual swirlers at different outlet angle; co-swirl and counter-swirl. To understand the characteristics of turbulent spray combustion of dual swril flow(DSF), the axial helical annular vaned swirlers with various swirl ratios and combination of angle and direction were designed. and temperature measurements of a rapidly thermocouple insertion and measurements of soot volume fraction and microrstructure using thermophoretic sampling particle diagnostic(TSPD) as TEM were carried out. The NOx, $CO_2$,$O_2$, etc. was analyzed using emission gas analyzer. The results show that flame stability were maintained under very lean condition. for both co-swirl and counter-swirl case. And though Counter-swirl case kept the higher temperature region compared to co-swirl case, Counter-swirl combustion represented less NOx emission and soot formation than co-swirl case.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.242-247
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• 2004

An Experimental study was conducted on spray combustion using dual swirlers at different outlet angle; co-swirl and counter-swirl. To understand the characteristics of turbulent spray combustion of dual swirl flow (DSF), the axial helical annular vaned swirlers with various swirl ratios and combination of angle and direction were designed. and temperature measurements of a rapidly thermocouple insertion and measurements of soot volume fraction and microrstructure using thermophoretic sampling particle diagnostic (TSPD) as TEM were carried out. The NOx, $CO_2$, $O_2$, etc. was analyzed using emission gas analyzer. The results show that flame stability were maintained under very lean condition. for both co-swirl and counter-swirl case. And though Counter-swirl case kept the higher temperature region compared to co-swirl case, Counter-swirl combustion represented less NOx emission and soot formation than co-swirl case.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.1
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• pp.51-56
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• 2008

The counter-fire operation system performs its mission exchanging information with other related systems such as command & control systems and military information systems. In the process of exchanging information, the counter-fire operation system uses a type of data message which contains exchange data information in the format of KMTF. The requirement of data exchange of count-fire operation will continue to evolve. But the EDX(External Data eXchange) configuration item of the current counter-fire operation system can not effectively cope with the variation of data exchange requirements due to its fixed software structure. In the paper, a solution for improving flexibility of external data exchange in counter-fire operation system is proposed.

• Progress in Superconductivity and Cryogenics
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• v.7 no.1
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• pp.17-20
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• 2005

We has designed, fabricated, and measured a Single flux quantum (SFQ) toggle flip-flop (TFF). The TFF is widely used in superconductive digital electronics circuits. Many digital devices, such as frequency counter, counting ADC and program counter be used TFF Specially, a program counter may be constructed based on TFF We have designed the newly TFF and obtained high bias margins on test. In this work, we used two circuit simulation tools, WRspice and Julia, as circuit optimization tools. We used XIC for a layout tool. Newly designed TFF had minimum bias margins of +/- $37\%$ and maximum bias margins of +/-$37\%$(enhanced from +/- $37\%$). The designed circuits were fabricated by using Nb technology The test results showed that the re-optimized TFF operated correctly on 100kHz and had a very wide bias margins of +/- $53\%$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1134-1137
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• 2004

The main function of surge counter is knowing the times of surge flowed in, which is installed under surge arrester. Two methods are presented in this paper to get the electric power for mechanical movement and detect the surge with surge counter. One is using ZnO varistor resister and the other is using the current transformer.

• Journal of the Korean Society of Combustion
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• v.5 no.1
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• pp.67-79
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• 2000

An Experimental study was conducted on spray combustion using dual swirlers at different outlet angle; co-swirl and counter-swirl. To understand the characteristics of turbulent spray combustion of dual swril flow(DSF), the axial helical annular vaned swirlers with various swirl ratios and combination of angle and direction were designed. and temperature measurements of a rapidly thermocouple insertion and measurements of soot volume fraction and microstructure using thermophoretic sampling particle diagnostic(TSPD) as TEM were carried out. The NOx, $CO_2,\;O_2$, etc. was analyzed using emission gas analyzer. The results show that flame stability were maintained under very lean condition. for both co-swirl and counter-swirl case. And though Counter-swirl case kept the higher temperature region compared to co-swirl case, Counter-swirl combustion represented less NOx emission and soot formation than co-swirl case.

• The Korean Journal of Ceramics
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• v.6 no.3
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• pp.280-285
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• 2000

The electrolyte, $(HO)_2C_6H_2(SO_3Na)_2H_2O $(Tiron), disperses efficiently alumina powder in aqueous media and stable suspensions with 60 vol% solid loading can be prepared. The strong adsorption of this additive is mainly due to the ability of the molecule to form chelate rings with the particle surface but electrostatic interactions between the surface charge and the anionic dispersant strongly influence the amount of Tiron adsorbed. By using a cationic exchange route to substitute the counter ion which neutralizes the sulfonate groups, new molecules of dispersant have been prepared, either with mineral cations as $Li^+,\; Na+^,\; NH_4^\;+$, or with organic cations as counter ion but organic counter ions lead to less to less viscous suspensions than $Na^+$ in particular when the number of carbon atoms of the aliphatic chain increases from 1 to 3.