• Korean Journal of Materials Research
• /
• v.21 no.2
• /
• pp.73-77
• /
• 2011

Specific heat of a crystal is the sum of electronic specific heat, which is the specific heat of conduction electrons, and lattice specific heat, which is the specific heat of the lattice. Since properties such as crystal structure and Debye temperature do not change even in the superconducting state, the lattice specific heat may remain unchanged between the normal and the superconducting state. The difference of specific heat between the normal and superconducting state may be caused only by the electronic specific heat difference between the normal and superconducting states. Critical temperature, at which transition occurs, becomes lower than $T_{c0}$ under the influence of a magnetic field. It is well known that specific heat also changes abruptly at this critical temperature, but magnetic field dependence of jump of specific heat has not yet been developed theoretically. In this paper, specific heat jump of superconducting crystals at low temperature is derived as an explicit function of applied magnetic field H by using the thermodynamic relations of A. C. Rose-Innes and E. H. Rhoderick. The derived specific heat jump is compared with experimental data for superconducting crystals of $MgCNi_3$, $LiTi_2O_4$ and $Nd_{0.5}Ca_{0.5}MnO_3$. Our specific heat jump function well explains the jump up or down phenomena of superconducting crystals.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.14 no.1
• /
• pp.17-20
• /
• 2004

We derive specific heat gap at the critical temperature as an exact anylitical function of applied magnetic field by using the thermodynamics. And we calculate numerical value of specific heat gap for some superconductors with the derived results and discuss the physical meaning. And it will be discussed that gap of specific heat discontinuity under certain magnetic field intensity become zero at the critical temperature.

• Proceedings of the KIEE Conference
• /
• 2001.07a
• /
• pp.407-409
• /
• 2001

상용주파 자계와 인체의 건강에 대해서 과학적인 해명 목적으로 Specific Pathegen Free Room을 제작하였다. 환경 실험실의 설치조건 중 자계 노출장 치간의 Stray Field의 영향이 중요하므로 SPF Room을 배치하는 데 있어 각 자계노출장치의 Stray Field로 인한 노출장치의 자계 균일도를 예측 계산하고 그 결과를 바탕으로 최적 배치를 구하였으며 실제 자계 균일도를 측정한 결과 목표한 바와 같이 2%이내임을 확인하였다.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.13 no.1
• /
• pp.23-28
• /
• 2018

We derive a gap of specific heat discontinuity of superconducting crystals theoretically at the critical temperature $T_{CH}$ as an explicit function of applied magnetic field H by using the thermodynamic relations for Gibbs free energy and the linear model for the critical magnetic field $H_{CT}$. The derived a gap of specific heat discontinuity is compared with experimental results by J. Kacmarcik et al. for superconducting MgCNi3 crystal. Our specific heat gap function well explain the jump up phenomena of the superconducting crystals.

• Journal of IKEEE
• /
• v.17 no.2
• /
• pp.129-134
• /
• 2013

For the conventional power metal-oxide semiconductor field-effect transistor (MOSFET) device structure, there exists a tradeoff relationship between specific on-resistance ($R_{ON.SP}$) and breakdown voltage ($V_{BR}$). In order to overcome the tradeoff relationship, a uniform super-junction (SJ) trench metal-oxide semiconductor field-effect transistor (TMOSFET) structure is studied and designed. The structure modeling considering doping concentrations is performed, and the distributions at breakdown voltages and the electric fields in a SJ TMOSFET are analyzed. The simulations are successfully optimized by the using of the SILVACO TCAD 2D device simulator, Atlas. In this paper, the specific on-resistance of the SJ TMOSFET is successfully obtained 0.96 $m{\Omega}{\cdot}cm^2$, which is of lesser value than the required one of 1.2 $m{\Omega}{\cdot}cm^2$ at the class of 100 V and 100 A for BLDC motor.

• Journal of Radiation Protection and Research
• /
• v.25 no.2
• /
• pp.109-114
• /
• 2000

The SI unit of specific absorption rate (SAR) in W/kg in the electromagnetic (EM) field as non-ionizing radiation is exactly same as the SI unit of absorbed dose rate in Gy/s in the ionizing radiation field. The SI unit of both physical quantities can be expressed in $[m^{\cdot}s^{-3}]$. Where, the unit of absorbed dose, Gy stands for Gray. In EM biological interactions, the SAR equations are derived and the characteristics of EM field energy absorption in terms of the SAR are discussed and described on the mathematical basis.

• Journal of Family Resource Management and Policy Review
• /
• v.24 no.3
• /
• pp.1-17
• /
• 2020

This study aimed to suggest the direction and guideline of specific program for single households in the Healthy Families Support Centers. This study focused on Seoul area. To collect the data the in-depth interviews for 9 staffs managing the program for single person in field are progressed. The major results were as follows. First, we found the demand and validity of a specific program for single person households. Because they are different each other in the context of age, sex, marriage experience, everyday life and need for program. So the specific programs can give higher satisfaction to the single person household. Second, to manage the specific program effectively in field we need the retraining of staffs, sharing materials between centers and other institutions, presentation and communication about the information on program management in field.

• Journal of Biosystems Engineering
• /
• v.24 no.3
• /
• pp.195-208
• /
• 1999

A computer simulation was carried out to investigate draft characteristics of Korean paddy field for obtaining the basic reference to the selection of optimum moldboard type suitable for Korean paddy field conditions. Cylindrical, cylindroidal, semihelical moldboard plows, and one type of oriental Janggi were used for simulation. A series of soil bin experiments was conducted to compare the experimental results with the predicted drafts from computer simulation using the cylindroidal moldboard plow. The computer model predicted draft force with 1~12% error at 12~16cm plowing depth which is the most conventional plowing depth in the rural area in Korea. Thus, the computer model was considered to be good enough for simulation. Due to the different plowing width of experimental plows, specific draft was selected for comparison by computer simulations. Specific draft of cylindrical moldboard plow was ranged from 3 to 6 N/$\textrm{cm}^2$ according to the soil conditions, plowing speed and plowing depth, 2.5~3.0 N/$\textrm{cm}^2$ for semihelical moldboard plow.

• Korean Journal of Mathematics
• /
• v.4 no.2
• /
• pp.141-148
• /
• 1996

• International Journal of Highway Engineering
• /
• v.18 no.5
• /
• pp.21-29
• /
• 2016

PURPOSES : The purpose of this study is to suggest a specific investigation guideline to decide priority of repairing old concrete pavements that pile up substantially. METHODS : In this study, a principle of division of homogeneous sections was proposed to reflect the characteristics of the pavement reasonably in the specific investigation results. In addition, a checklist and guideline of field investigation were suggested for the old concrete pavement sections, which require inspection toward their durability and structural performance. Furthermore, the items of laboratory test necessary to the old concrete pavement were suggested based on the existing laboratory test considering characteristics of the old concrete pavement. The present condition of the old concrete pavement could be analyzed by the test results. RESULTS : A method of division of homogeneous sections suitable for the specific investigation of the old concrete pavement was suggested. The proportions of distress severity of pavement sections were compared by distress type to figure out the present state of the old concrete pavement. Scaling, durability cracking (or alkali-silica reaction), and longitudinal spalling were selected as the most severe distress types. The detailed positions of the sections were also suggested. The checklist of the specific investigation was categorized by field survey and laboratory test, and its evaluation criteria were proposed. The three types of the sections of durability cracking (or alkali-silica reaction), bridge connection, and asphalt overlay were selected as the sections of the field survey. The compressive strength, void structure, and chloride penetration depth were suggested as the items of the laboratory test. CONCLUSIONS : A fundamental level of the guideline was suggested in this study to resolve the problem of old concrete pavement. Appropriate guidelines related to the repair of the old concrete pavement should be provided by performing additional research efforts.