• Journal of the Korean institute of surface engineering
• /
• v.30 no.3
• /
• pp.183-190
• /
• 1997

Fabrication and crystallization characteristics of yttria($T_2O_3$) stabilized zirconia(YSZ) thin film by sol-gel process were studied. YSZ sol was synthesized with zirconium n-propoxide($Zr(OC_3H_7)_4)$) and yttrium nitrate pentahydrate ($Y(NO_3)_3.5H_2O$). YSZ film was prepared by depositing the polymeric sol on porous $Al_2O_3$ substrate by spin-coating, and the film characteristics were investigated by FRIR, TG-DTA, XRD, DSC, optical microscopy and SEM. The film topology was uniform and cracks were not found. It was found that the annealing temperature and the concentration of stabilizer affect the crystallization of YSZ film. The YSZ film began to crystallize from amorphous to tetragonal phase at 40$0^{\circ}C$, and it was not converted to cubic structure until $1100^{\circ}C$. It seemed that the grains were formed over $700^{\circ}C$and the average grain size was obtained about 0.2$\mu\textrm{m}$.

• The Korean Journal of Pain
• /
• v.8 no.2
• /
• pp.378-382
• /
• 1995

Continuous epidural blockade has been used widely for providing anesthesia and analgesia. But many kinds of unusual complications have been reported such as: kinking, knotting, shearing, abnormal positions of catheter, etc. We experienced a case of malposition of the catheter which pass out the epidural space through the intervertebral foramen in a 33-year-old cancer patient. We confirmed it by epidurogram.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.32A no.7
• /
• pp.94-103
• /
• 1995

Thin film acoustooptic beam deflector in proton-exchanged Y-cut LiNbO$_{3}$ was fabricated and measured. The planar waveguide was fabricated by using the proton-exchanged and annealing method in Y0cut LiNbO$_{3}$. Interdigital transducer for SAW(surface acoustic wave) was made by the laser lithography. Using above method, the thin film acoustooptic beam deflector was constructed. Its SAW wavelength was 20.mu.m at 174MHz center frequency. The interaction length between guided optical wave and SAW was 2.16mm. The measured 3dB bandwidth was 17MHz using He-Ne laser. And 70% diffraction efficiency was obtained at 970mW RF driving power.

• Journal of Environmental Science International
• /
• v.11 no.4
• /
• pp.333-338
• /
• 2002

In this work, the characterization of adsorption of Cu, Zn and Cd on granular activated carbon in water has been studied. The factors that affect adsorption in boundary between activated carbon and wastewater are concentration, temperature, contact time, pH and so on. As the result of this study, the maximum adsorption amount of Cu occurred near pH 7, while that of Zn and Cd was near pH 9.6 and 10, respectively. As contact time and temperature are transformed, such factors as optimum contact time and temperature are taken into consideration in an adsorptive process of heavy metal because an adsorption and a reducing process occur. In isotherm of Freundlich, 1/n values of Cu, Cd capacity were between 0.16 and 0.5.

• Corrosion Science and Technology
• /
• v.8 no.6
• /
• pp.232-237
• /
• 2009

Copper tubes are widely used in the distribution systems of drinking water throughout the world because of their excellent corrosion resistance, high thermal conductivity, and ease of fabrication. However, corrosion problems from copper tubes as blue water phenomenon and leakage have been reported appreciably. The effect of pH on the corrosion behavior of copper tube for tap water was investigated by electrochemical voltammetric techniques in synthetic tap water. And the copper corrosion cases were discussed from the viewpoint of factors affecting the corrosion rate such as pH, alkalinity, LSI(Langelier Saturation Index), and concentration of bicarbonate and dissolved carbon dioxide.

• KOREAN POULTRY JOURNAL
• /
• v.36 no.8 s.418
• /
• pp.70-74
• /
• 2004

계사환경을 쾌적하게 하고 생산성을 향상시키고자 하는 것은 모든 양계인들의 바람이다. 특히, 요즘과 같은 여름철의 경우 고온 다습한 기후로 인해 계분처리가 잘 이루어지지 않을 경우 계사내 악취방생으로 인해 계사환경이 나빠질 수 있으며, 겨울철이나 환절기에는 환기부족에 따른 가스발생으로 닭들의 생산성 저하를 가져오기도 한다. 즉, 계분에 따른 악취발생은 호흡기 질환의 원인이 되고, 악취스트레스, 소화불량, 사료섭취 저하 등으로 인해 폐사율이 증가하여 결국 생산성저하 현상이 높게 나타날 수 있다. 따라서 최근 축산환경개선이라는 포괄적인 문제를 해결하기 위하여 관련업계에서 다양한 실험과 연구결과가 속속 발표되고 있으며, 양계분야에서도 환경개선은 물론 생산성 향상을 기할 수 있는 대체 물질이 개발, 사용되어지면서 업계의 비상한 관심을 모으고 있다. 본지가 찾은 곳은 자연미생물을 이용해 계분의 악취를 제거하고 생산성 향상을 기하고 있는 농가(일심농장)와 공급업체인 운석바이오(대표 이종수)를 찾아 국내 축산환경개선 방안을 점거해 보고자 한다.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.11a
• /
• pp.164-165
• /
• 2013

This study is on the performance evaluation of concrete being used the CaMg based low carbon cement(LCC) as a binder and the rapidly cooled electric arc furnace oxidizing slag(EAF slag) as a fine aggregate. When using the sand as a fine aggregate, compressive strength of the concrete using LCC, as a binder, was reduced 9% comparing with that of OPC concrete. However, when using the EAF slag as a fine aggregate, the compressive strength was increased by 9%. We found that combination LCC and EAF slag contribute to the strength properties of concrete.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.4
• /
• pp.605-610
• /
• 1997

An analysis method for the electromagnetic scattering of a Tm polarized plane wave from a periodic strip grating over a grounded dielectric slab is considered from the viewpoint of reflection grating problem. The parameters of strip gratings showing Bargg and Off-Bragg blazing phenomena at the frequency of 10GHz are derived teoretically. The strip grating structure is implemented using Aluminum plate(groung conductor), paraffin(dielectric material.epsilon.$_{r}$=2.24), and copper(strip conductor0.08m thickness). The experimental results(reflection power) of Bragg as well as Off-Bragg blazing phenomenon for TM polarized plane wave have been compared with the theoretical results and fairly good agreements between theory and experiment have been observed.d.

• Journal of the Korean institute of surface engineering
• /
• v.48 no.3
• /
• pp.100-104
• /
• 2015

The nickel alloys gets a great deal of attention due to their good mechanical, chemical and magnetic properties. Especially Ni-P alloy systems are very attractive due to their good corrosion resistance and the wear resistance in important technological applications. In this study, the effects of phosphorus acid concentration in plating solution on composition of Ni-P alloy coatings were studied. The Ni-P electrodeposits of the various P contents were investigated in order to understand effect of the composition on mechanical properties of Ni-P electrodeposits. The mechanical properties of electrodeposits increased as the P content in electrodeposits increase. The results of mechanical properties were explained by grain size and P solid solution effect. The effects of heat treatment on mechanical properties of Ni-P alloy coatings were also studied.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2006.05a
• /
• pp.749-753
• /
• 2006

Since the appearance of the first computer virus in 1986, a significant number of new viruses has appeared every year. Recently, there has been a marked increase in the number of mobile malicious code(virus, worm, trojan) in Mobile devices(smart phone, PDA). As a growing number of people use mobile device, we have to prepare for coming mobile attacks. In this paper, we study trends and characteristics of mobile malicious code. And, we describe considerations of on-device and network security in mobile environment.