• Progress in Superconductivity
• /
• v.14 no.1
• /
• pp.1-10
• /
• 2012

We fabricated a closed coils by using resistive-joint method and the joint resistance of the coils were estimated by field decay technique in liquid nitrogen. We used the Runge-kutta method for the numerical analysis to calculate the decay properties. The closed coil was wound by $(Bi,Pb)_2Sr_2Ca_2Cu_3O_x$/Ag tape. Both ends the tape were overlapped and soldered to each other. The current was induced in a closed coils by external magnetic flux density. Its decay characteristic was observed by means of measuring the magnetic flux density generated by induced current at the center of the closed coil with hall sensor. The joint resistance was calculated as the ratio of the inductance of the loop to the time constants. The joint resistances were evaluated as a function of critical current of loop, contact length, sweep time, and external magnetic flux density in a contact length of 7 cm. It was observed that joint resistance was dependent on contact length of a closed coil, but independent of critical current, sweep time, and external magnetic flux density. The joint resistance was measured to be higher for a standard four-probe method, compared with that for the field decay technique. This implies that noise of measurement in a standard four-probe method is larger than that of field decay technique. It was estimated that joint resistance was $8.0{\times}10^{-9}{\Omega}$ to $11.4{\times}10^{-9}{\Omega}$ for coils of contact length for 7 cm. It was found that 40Pb/60Sn solder are unsuitable for persistent mode.

• Journal of the Korean Institute of Rural Architecture
• /
• v.15 no.4
• /
• pp.1-8
• /
• 2013

The Rural Housing Standard Plans for improving the quality of life and housing stability in rural areas has been developed 87 types from 1994 to 2012. However, some types of Plans do not satisfy the current legal standard in accordance with social and legal changes. Standard plans has the same effect as a building permit, and replace it, so legal suitability of Plans is an important. Therefore, it is required the suitability analysis on the legal standards of Rural Housing Standard Plans. The Purpose of this study is to derive improper types and items of the Rural Housing Standard Plans on the legal standards. In this study, we analyzed its suitability on the legal standards(law on fire-fighting system installation and safety management, energy saving design criteria for buildings, structural checklist for small buildings, the types of drawing for building permit) in accordance with "rules for the operation of standard plans". And we analyzed the utilization of the Rural Housing Standard Plans through downloads from welchon portal.

• Progress in Superconductivity and Cryogenics
• /
• v.15 no.3
• /
• pp.9-12
• /
• 2013

Current-voltage characteristic models of superconducting material are suggested by many researchers. These current-voltage characteristic models are important because they can be used for design or simulation of superconductor devices. But widely used current-voltage models of superconductor wire still have some limitations. For example, a standard E-J power model has no parameters related with stabilizer's resistance in superconductor wire. In this paper, a current-voltage characteristic modeling method for high temperature superconductor (HTS) tape with considering the effect of stabilizer is introduced. And a current-voltage characteristic of a HTS tape is measured under different stabilizer conditions. Those measured current-voltage characteristics of the HTS tape modeled with proposed modeling method and the modeling results are compared.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.9
• /
• pp.584-589
• /
• 2000

We fabricated resistive superconducting fault current limiters (SFCL) based on YBCO thin films grown on a 2-inch diameter Al2O3 substrate. The current limiting element was 1 mm wide and 260mm long meander line prepared by standard photolithography. The minimum quench current of the current limiting element was about 8 Apeak. This SFCL sucessfully controlled the fault current below 14.3 Apeak at the voltage of 100 Apeak which is otherwise to increase up to 141 Apeak. The quench completion time was less than 3 msec. The temperature of the current limiting element rose to about 200 K in 3 cycles after fault. The SFCL showed reproducible quench during hundreds times of repeated experiments.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.34C no.11
• /
• pp.56-65
• /
• 1997

In this paper, a design of current-mode continuous-time filters for low voltage and high frequency applictions using complementary bipolar current mirror paris is presented. The proposed current-mode filters consist of simple bipolar current mirrors and capacitors and are quite suitable for monolithic integrtion. Since the design method of the proposed curent-mode filters is based on the integrator type of realization, it can be used for a wide range of applications. And the cutoff frequency of th efilters can be easily changed by the DC cntrolling current. As design examples, the 5th order butterworth filters are designed by cascade and leapfrog methods with tunable cutoff frequencies from 30MHz to 100MHz. The characteristics of the designed current mode filters are simulated and examined by SPICE using standard bipolar transistor parameters.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.55 no.8
• /
• pp.396-402
• /
• 2006

Even the case DC circuit Breaker have good quality for interruption of high current like heavy load current, short-circuit current, the verification for small current breaking capability of circuit breaker should be performed. It comes from the reason DC small current breaking failure can be lead to break out second heavy fault condition and in the long run substation shutdown. In this paper, we can find the characteristics of DC small current and international test standard discription about small current breaking and one of the proper solution to get over it.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.12
• /
• pp.2127-2137
• /
• 2016

In this paper, characteristic tests for current transformers with maximum mA secondary current of 250 mA is performed. The purpose of this paper is not only to test the mA current transformers by following the IEEE Draft Standard for Current Transformers with Maximum mA Secondary Current of 250mA, but also to take into consideration certain applications in the use of the mA CTs for billing purposes.

• International Journal of Highway Engineering
• /
• v.8 no.1 s.27
• /
• pp.89-98
• /
• 2006

The weight-to-power ratio of the standard truck for the climbing lane design is known to be 200lb/hp. The value was known to be assumed based on constant trucks' capability and regional distributions in stead of widely varied distributions region by region. Additionally, this value was assumed after investigating registered vehicles' statistics instead of investigating real portions of truck volumes. Therefore, it may be said that the value of the current standard truck does not reflect regional or industrial diversity and proportions of truck volumes. To resolve these issues, the present paper studies diversified standard trucks which consider regionally or industrially diversified and observed-volume based weigh-to-power ratios. For this purpose, individual trucks' weigh-to-power ratios obtained at toll-gates of national expressways were used. For regionally based study, the whole nation are divided into 8 regions, then each region is characterized by a unit of a weigh-to-power ratio. The applicability of each value is provided. Results show that the single value for the nationwide standard truck may be 208 lb/hp, 8 lb/hp higher than the current value of 200 lb/hp. Results also show that regional values ranged widely from 170 lb/hp to 230 lb, 30 lb/hp higher/lower than the current value. Conclusively, regional diversity of trucks' weigh-to-power ratios was identified then three types of standardized weigh-to-power ratios which may represent regional characteristics were suggested. As the diversified standard truck are applied to the design standard, two benefits are expected such as decrease of rear-end accident rates or decrease of climb lane construction costs.

• Korean Journal of Biological Psychiatry
• /
• v.5 no.2
• /
• pp.175-183
• /
• 1998

To consider current concepts of epilepsy further, the brief review begins with a discussion of what is epilepsy, discribes multifactorial nature of epileptic disorders, and ends with a presentation of current classifications. A combination of the standard antiepielptic drugs(AEDs) may be necessary to treat intractable seizures, but no studies have been done to indicate an optimal combination. The new AEDs provide alternative choices, but questions remain about the optimal timing and manner of administration. AEDs selection must individualized, no drug of choice can be named for all patients.

• Proceedings of the KIEE Conference
• /
• 2001.07a
• /
• pp.437-439
• /
• 2001

The plan of intercomparison test for high-current system was discussed concretely in the technical committee of STL in 2000. This paper describes the present state of the world, the plan & procedure of intercomparison test and test expenses for high-current system. In conclusion, this mentioned the matters that our country should prepare urgently.