• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1992년도 하계학술대회 논문집 B
• /
• pp.891-893
• /
• 1992

Polymers have good electrical properties as an insulation material. Though they show more and less poor resistance to heat, radiation, and oxygen, the poor properties have been overcame by developing new resin with the saturated molecular structure and compounding resin with resistive fillers. Polymer insulators have many advantages; light weight, good mechanical properties, better contaimination performance, low cost by mass productivity, no destruction in many pieces, good flexibility in design, short manufacturing time. Usage of polymer insulators has increased rapidly with good credit on long term properties in advanced nations and will continue to grow.

• 한국의류산업학회지
• /
• 제4권6호
• /
• pp.544-549
• /
• 2002

By the movable thermal manikin developed by China Dong Hua university, the laws of clothing thermal insulation influenced by dressing poses are studied. It is found that $I_a$ on nude thermal manikin has no relation to testing pose as a whole (notable level is 5%), while the change of testing pose influences $I_a$ value on parts of body obviously. The testing result $I_{cle}$ on clothed thermal manikin has relation to testing pose. The $I_{cle}$ value of the whole body in seated pose decreases 20 percent compared with that in standing pose (notable level is 1%). In view of heat transmission theory, the reasons are pointed out based on the knowledge of heat transmission.

• 한국의류학회지
• /
• 제23권8호
• /
• pp.1098-1109
• /
• 1999

This study was to examine the effects of textiles materials and wearing types on the thermal regulation responses of human, Cotton polyester wool silk and rayon were chosen as outerwears and acetate was selected as a lining. Blouse-skirt suits blouse-slacks suits and one-piece dress made of selected textiles were examined by human trials, Tests results were as follows ; 1 When subjects wore vlouse-slacks suits Tmsk was showed the highest value. There was a significant difference on Tmsk(p<0.05) when they wore one-piece dress. The temperature of microclimate inside clothing when subjects wore blouse-slacks suits showed the highest value and one-piece dress and then blouse-skirt suits in order. For blouse-skirt suits clothing without lining showed higher temperature of the back of microclimate inside clothing than clothing with lining except cotton(p<0.1) 2. There were no significant consistency of the increasing rates of thermal insulation of garment at fabric test and human trials among polyesterand silk.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2023년도 봄 학술논문 발표대회
• /
• pp.227-228
• /
• 2023

This study is tocompare and analyze the results of hydration heat analysis and on-field measurements using the method with hydration heat difference and insulation curing method for controlling hydration heat in mass concrete. As a result of the analysis, the temperature difference between the center and the surface was predicted very similarly, and the mass concrete surface was controlled to a safe level when evaluating with a temperature crack index, and after being finished, it was confirmed that there was no hydration crack.

• Transactions on Electrical and Electronic Materials
• /
• 제13권3호
• /
• pp.116-120
• /
• 2012

In this paper, ZnO-Epoxy nanocomposites (NEP) were prepared and epoxy composites that contain 5 wt% micro ZnO (MEP) and deliberately not well dispersed nano ZnO (NDNEP) were also prepared for purpose of comparison. The effects of the particle size and dispersion of ZnO on dielectric properties of epoxy resin were chiefly studied. Test results showed that: at a loading of 5 wt%, the three epoxy composites seem to have no significant difference on resistivity compared to epoxy resin; Dielectric constants of all the epoxy composites are also basically the same but they are bigger compared to that of the pure epoxy resin (unfilled); Dielectric dissipation factors ($tan{\delta}$) of NDNEP is greater than that of NEP and MEP. NEP has the minimum dielectric loss factor, whereas dielectric loss factors of the three epoxy composites are larger than that of the pure epoxy resin. The decreasing order of electrical breakdown strength for the three epoxy composites and for the pure epoxy resin is as follows: NEP>MEP>NDNEP>EP. Finally, in order to explain the experimental results the aggregation interface phase was proposed. Furthermore, addition of well dispersed nano filler has proved to have a positive effect on the improvement of the dielectric properties of epoxy resin.

• 전기학회논문지
• /
• 제58권1호
• /
• pp.132-136
• /
• 2009

Recently, for improvement of the magnetic field of high temperature superconductor (HTS) apparatus, many studies investigating on operating in the range of $20{\sim}65\;K$ with liquid helium or the conducting method using cryocooler are actively reviewed. Also, the cooling method using solid nitrogen as cryogen is being suggested. Since the nitrogen has very large specific heat in solid state, it is expected that it can be operated for a long time without a continuous supply of cooling energy. However, there are still insufficient data on the characteristics of solid nitrogen such as thermodynamic properties and liquid-solid phase change. Especially, there was almost no study done on the electrical insulation properties of solid nitrogen so far. In this study, solid nitrogen to find the electrical characteristics was made by using cryocooler and cryostat, and investigated the flashover discharge and breakdown. The results of this study will be useful as a basic data for electrical insulation design of the HTS system using solid nitrogen as cryogen.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2008년도 춘계 학술논문 발표대회
• /
• pp.57-60
• /
• 2008

This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete and mass concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 6 and 15℃ even in case outside temperature drops -9℃ below zero until the 2nd day from piling, and in the case of mass concrete, with the maximum temperature difference between the center and surface less than 4℃, crack occurrence index was close to 2 and no hydration heat crack occurred by internal constraint. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
• /
• pp.153-155
• /
• 2011

In this study, an insulation panel system that has the most excellent economic feasibility in a long term LCC viewpoint in some analysis, which determine a proper insulation panel construction method for the out wall of structures, is analyzed. As a result, in the case of a deterministic LCC analysis, the initial investment cost represents about 80,000Won/㎡ for extrusion ceramic panels. Also, although the costs of maintenance, disassembling, and disposal show no large differences compared with other panel systems, metal panels indicate a bit higher than other panel systems about 1.5 times. In the probability density function that analyzes the variation of the probabilistic cost between panel systems and its economic feasibility, metal panels show the highest cost distribution and extrusion and stone panels represent low cost distributions. In the cumulative function distribution that composites probability density functions, the extrusion ceramic panel represents the most excellent economic feasibility and reliability and that is also the most superior subject among the subjects used in this study.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 B
• /
• pp.1015-1017
• /
• 2003

In a research and development team of high temperature superconducting (HTS) transformer for power distribution, prior to manufacture a single phase 1MVA 22.9 kV/6.6 kV HTS transformer, a 1MVA transformer for insulation test with windings made of copper tapes with the same size as BSCCO-2223 HTS tape was manufactured. The test transformer was composed of both the copper windings of double pancake type and the shell type core of laminated silicon steel plates. The characteristics tests of the test transformer were performed, such as no load test, load test and short test at 77k using liquid nitrogen. Insulation tests, lightning impulse test, power-frequency voltage test and external insulation test, were accomplished also.

• 한국초전도ㆍ저온공학회논문지
• /
• 제20권4호
• /
• pp.26-30
• /
• 2018

The turn-to-turn contact resistance of 2G high temperature superconducting (HTS) coils with metal insulation (MI) is closely related to the stability of the coils, current charging rate and delay time [1]. MI coils were fabricated using five kinds of metal tapes such as aluminum (Al) tape, brass tape, stainless steel (SS) tape, copper (Cu)-plated tape and one-sided Cu-plated SS tape. The turn-to-turn contact surface resistances of co-winding model coils using Al tape, brass tape, and SS tape were 342.6, 343.6 and $724.8{\mu}{\Omega}{\cdot}cm^2$, respectively. The turn-to-turn contact resistance of the model coil using the one-sided Cu-plated SS tape was $ 248.8{\mu}{\Omega}{\cdot}cm^2$, which was lower than that of Al and brass tape. Al or brass tape can be used to reduce contact resistance and improve the stability of the coil. Considering strength, SS tape is recommended. For strength and low contact resistance, SS tape with copper plating on one side can be used.