• 대한디지털의료영상학회논문지
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• 제12권2호
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• pp.145-150
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• 2010

Thick films of carbon fiber were prepared by a heating element of plan shape made in Darin co., We have investigated surface morphology of the specimen depending on heat-treatment temperatures. Scanning electron microscope(SEM) image of carbon fiber thick films of the specimen heat treated shows a grain growth at $1200^{\circ}C$ and becomes a poly-crystallization at $1350^{\circ}C$. The variation of resistivity at the thermally annealed specimen above $600^{\circ}C$ depends on type of the substrates. It may be due to a variation of film thickness and a difference of interfacial phenomena. A heating element of features was affected significantly by skin blood and quantity of heat of the body physiological function. After radiation of farinfrared for plate heating element, the function of biometric physiological is considered of skin blood flow and calorie which greatly affects on individuals. Electromagnetic wave was not influence on the body.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.193-194
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• 2006

A solid freeform fabrication (SFF) system using selective laser sintering (SLS) is currently recognized as a leading process and SLS extends the applications to machinery and automobiles due to the variousmaterials employed. In order to develop a more elaborate and rapid system for fabricating large objects compared to existing SLS, this study employs a new selective dual-laser sintering (SDLS) process. Also, this paper will address development of an SFF system which employs the dual laser system and the unique scanning device. Experiments were performed to evaluate the effect of a scanning path and fabrication parameters on sintering process and to fabricate the various 3D objects using polymer powder.

• Macromolecular Research
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• 제11권4호
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• pp.283-290
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• 2003

Organic drugs including aspirin, omeprazole, and naproxen with three different levels of octanol/water partition coefficient were examined for their release behavior from the amphiphilic PCL-b-PEO-b-PCL (PCEC) matrix. Scanning electron micrograph (SEM) of PCEC illustrated a well defined two-phase morphology consisted of dispersed poly(ethylene oxide) (PEO) domain and continuous polycaprolactone (PCL) phase. Differential scanning calorimetry (DSC) and X-ray diffractometry (XRD) experiments veri tied that three model drugs are dissolved as a molecular dispersion in PCEC matrix. The release of hydrophilic aspirin closely followed the water absorption profile of the matrix indicating that its major fraction is present in PEO domain. However, substantial amount of aspirin present in less hydrophilic region displayed discontinuous biphasic release pattern. In the case of omeprazole with intermediate hydrophobicity consistent release behavior was observed for a period of 24 hrs after the rapid liberation of ca. 10% of the drug presumably partitioned in PEO phase. It was ascribed to the fact that the progressive hydration of PCEC matrix gradually increased the chance of drug/water exposure to compensate the exhaustion of device. Naproxen with the highest octanol/water distribution coefficient among three model drugs exhibited a limited release of 35% for 24 hrs. Finally, hydroxypropyl methylcellulose phthalate (HPMCP)/PCEC blend matrix demonstrated an accelerated and quantitative release of hydrophobic naproxen by generating high porosity and thereby expanding polymer/water interface.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 논문집
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• pp.1-2
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• 2008

Thick films of Carbon fiber were prepared by a heating element of plan shape made in Darin co.. We have investigated surface morphology of the specimen depending on second heat-treatment temperatures. X-ray diffraction patterns of Carbon fiber thick films show that the specimen heat treated below $600^{\circ}C$ was an amorphous phase and the one heat treated above $1100^{\circ}C$ forms a poly-crystallization. Scanning electron microscope(SEM) image of Carbon fiber thick films of the specimen heat treated in between 900 and $1100^{\circ}C$ shows a grain growth. At $1100^{\circ}C$, the specimen stops grain-growing and becomes a poly-crystallization.

• 융합보안논문지
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• 제8권2호
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• pp.71-78
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• 2008

이 연구는 인터넷 망과 조직이 자체보안을 위해 별도로 구축한 내부 망을 하나의 망으로 합쳐서 통합 체계를 구축하여 경제적이며 안전하게 인터넷과 내부 응용 서비스를 사용하는 방안을 제시하고자 한다. 기존에 일부에서 사용되고 있는 망 전환 장치는 기계적인 한계가 있으며 인터넷과 내부 망을 위한 별도의 네트워크를 구성해야 하는 문제점 때문에 연동성과 보안의 목표인 인증 및 암호화에 대한 대책이 부족하고 체계 구축 시 많은 비용이 소요되는 단점이 있다. 이에 ATM Forum 역 다중화 기술과 IPSec을 적용하여 네트워크 성능을 향상하고 구축비용을 절감하며 신뢰성 있는 이중 방어 체계의 구축 방안을 제안하고자 한다. 아울러 망 관리 기술을 이용한 Scanning 공격 기술과 SNMP, Spooler Port 등의 취약점을 집중 분석한 후 본 논문에서 제안한 이중 방어 체계 기반의 대응 방안을 제시하였다.

• 전자공학회논문지S
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• 제35S권7호
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• pp.86-94
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• 1998

The rosette-scan seeker is a device mounted on the infrared guided missile. It offers the positions and iamges of target to missiles servo system by scanning a space about target in rosette pattern with a single detector. An instantaneous field of view (IFOV), which is a diameter of a detector moving along the path of the rosette pattern, has the property that its smaller size provide the less interference of background signals and detector noise. If its size is too small to voer the total field of view (TFOV), however, it produces the invisible regions in the TFOV. In this case, the invisible regions cause the performance of the seeker to deteriorate. For full scan-coverage, it is necessary to design the small IFOV without the invisible regions in the TFOV, as possible. In this paper, we propose the new method of designing the smaller IFOV than the conventional method and verify full coverage of the scanned region. By comparing the nose equivalent flux density (NEFD) of the proposed method with the that of the conventional one, we confirm that the former is better than the latter in terms of performance.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.132.2-132.2
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• 2013

Electrons in graphene make ballistic transport with very high mobility (${\sim}2{\times}105 $cm2V-1s-1), which holds promises for applications in fast electronic devices. However, such expectations have been hampered by the semi-metallicity or zero bandgap of graphene, which makes it impossible to completely turn off graphene transistor devices. Here, we report the observations of local bandgap modulations in Moir$\acute{e}$ patterned graphene on metal substrates using scanning tunneling microscopy and spectroscopy. The Moir$\acute{e}$ patterned graphene was made by combinations of self-assembly processes, and they showed additional electronic states that could be interpreted as sub-band states. Our experimental observations could be explained with orbital transitions of carbon atoms from sp2 to sp3, as supported by our density functional theory calculation results. Our findings will add new poweful components for device applications.

• 한국전기전자재료학회논문지
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• 제34권5호
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• pp.321-326
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• 2021

We fabricated BiAlO thin film by a solution process with a brush coating to be used as liquid crystal (LC) alignment layer. Solution-processed BiAlO was coated on the glass substrate by brush process. Prepared thin films were annealed at different temperatures of 80℃, 180℃, and 280℃. To verify whether the BiAlO film was formed properly, X-ray photoelectron spectroscopy analysis was performed on Bi and Al. Using a crystal rotation method by polarized optical microscopy, LC alignment state was evaluated. At the annealing temperature of 280℃, the uniform homogenous LC alignment was achieved. To reveal the mechanism of LC alignment by brush coating, field emission scanning electron microscope was used. Through this analysis, spin-coated and brush coated film surface were compared. It was revealed that physical anisotropy was induced by brush coating at a high annealing temperature. Particles were aligned in one direction along which brush coating was made, resulting in a physical anisotropy that affects a uniform LC alignment. Therefore, it was confirmed that brush coating combined with BiAlO thin film annealed at high temperature has a significant potential for LC alignment.

• 한국컴퓨터정보학회논문지
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• 제28권12호
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• pp.97-104
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• 2023

본 논문은 지향성 스피커를 이용한 유해조류 퇴치 시스템을 제안한다. 유해조류 퇴치를 위한 기존 사운드 시스템은 소음공해로 인한 문제와 단조로운 소리로 인하여 조류의 학습효과로 효과성이 저하되는 단점을 가진다. 본 논문에서는 지향성 스피커를 이용하여 주변의 소음을 최소화하고 스피커 구동 장치에 대해 상하 및 좌우 각도를 자유롭게 하여 활용성을 극대화하였다. 또한 다양한 스캐닝 패턴을 이용하여 학습효과로 인한 성능저하 문제를 해결하였다. 향후, 원격제어 기능과 조류 종류를 인식할 수 있는 딥러닝 모델을 적용하여 중앙통제가 가능한 플랫폼으로 발전시키고자 한다.

• 한국응용과학기술학회지
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• 제33권2호
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• pp.385-390
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• 2016

연구에서 나노 알루미나와 마그네지아의 첨가에 의한 304 스테인레스 스틸에 $170^{\circ}C$ 2시간 열 경화시켰다. 레이저유도 분광학에 의한 코팅된 시료를 전하결합 장치와 SEM을 활용한 장치를 설계하여 시험 측정하였다. 이 결과 나노 알루미나와 마그네지아가 함유된 세라믹 코팅이 나노 무기화합물이 함유되지 않은 시료보다 부착성, 내스크래치성이 우수하였으며, 또한 산용액속에서 시료의 질량감소의 변화가 매우 작았다. 그리하여 본 연구는 304 스테인레스 스틸의 내부식성을 개선하기 위해 시료가 코팅되었으며, 분석공정이 설계되어 고분해능 CCD와 함께 분석되었다. 요즈음, 스테인레스 스틸의 코팅은 산업에 특이응용이 발전됨에 따라 위생학, 우주항공, 기기장치, 관측 등의 분야 등에 산업적 요구가 증가되고 있다.