• Journal of The Korean Astronomical Society
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• v.29 no.2
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• pp.83-91
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• 1996

We present a model that rotating primordial blackholes(PBHs) produced at the end of inflation generate the random, non-oriented primordial magnetic field. PBHs are copiously produced as the Universe completes the cosmic phase transition via bubble nucleation and tunneling processes in the extended inflation hypothesis. The PBHs produced acquire angular momentum through the mutual tidal gravitational interaction. For PBHs of mass less than 1013g, one can show that the evaporation (photon) luminosity of PBHs exceeds the Eddington limit. Thus throughout the lifetime of the rotating PBH, radiation flow from the central blackhole along the Kerr-geodesic exerts torque to ambient plasma. In the process similar to the Bierman's battery mechanism electron current reaching up to the horizon scale is induced. For PBHs of Grand Unified Theories extended inflation with the symmetry breaking temperature of $T_{GUT}\;\~\;10^{10}$ GeV, which evaporate near decoupling, we find that they generate random, non-oriented magnetic fields of $\~10^{-11}G$ on the last-scattering surface on (the present comoving) scales of $\~O(10)Mpc$.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.86.1-86.1
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• 2012

나노재료와 나노기술의 연구개발 지원을 위하여 국가나노인프라인 나노종합팹센터에서 개발되고 있는 나노재료/나노현상의 실시간 관찰을 위한 SiN membrane chip 기술 및 나노그래핀 기반구축에 대한 최근 결과와 향후계획을 소개하고자 한다. 나노재료의 합성, 배열, 구조 등의 실시간 관찰을 가능하게 하기 위하여 제작된SiN membrane chip은 투과전자현미경(transmission electron microscope, TEM)에서 투명한 기판으로, 그 위에 나노재료를 합성, 배열하고 원하는 모양의 전극을 형성하여 나노재료 및 나노소자의 온도변화 및 전기적 특성 측정 등이 가능하다. 이러한 기술은 Ag, Sn, Cu 등 nano-cluster의 percolation 소자, SiN 및 Graphene 나노기공 소자, SiGe, BiTe, Si, ZnO 나노선 및 CNT의 내부구조변화, 상변화 등 다양한 나노재료/나노소자의 나노현상 관찰 및 해석에 적용되었다.

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.263-264
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• 2006

광대역 증폭기의 개발과 아울러 고출력 광섬유 레이저의 개발이 다양하게 이루어지고 있는 가운데,$^{[1]}$ 특히 유도 라만 산란특성을 이용한 광섬유 레이저가 지속적으로 개발되고 있다.$^{[2]}$phosphosilicate 광섬유를 이득 매질로 하여 저가의 광섬유 레이저를 구현하는가 하면$^{[3][4]}$, 게르마늄 도핑 광섬유를 이득 매질로 한 고효율의 광섬유 레이저가 꾸준히 개발되고 있으며,$^{[5]}$ 다파장 레이저의 개발 등의 여러 가지 광섬유 레이저 개발 가능성의 폭을 확장시키고 있다. 본 논문에서는 위의 선행 기술을 바탕으로 게르마늄 광섬유를 이용한5차 연쇄 라만 공진기를 구성하여,실제 라만 광섬유 증폭기에 적용한 발진 파장, 1445 nm 인 레이저를 구현하고, 그 특성을 논의하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.410-410
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• 2007

광섬유 내에 첨가되어 있는 $GeO_2$ 등의 물질을 얼 확산시켜서 만드는 열확산 코어 광섬유는 열확산 기술에 따른 광섬유의 MFD(Mode Field Diameter)를 국소적으로 확대하여 굴절률 분포를 변화시킨 광섬유로 혹의 비틀림 및 간격에 대한 허용범위가 넓어지게 하여 접속 손실을 감소시킬 수 있다. 본 연구에서는 열확산 코어 광섬유를 제조할 때 안정된 얼확산 문제를 해결하기 위한 방법으로 트윈 토치를 이용한 프레임 브러싱 기법의 안정화된 코어 확장형 광섬유 제조시스템을 제작하였다. 또한 제작된 열확산 코어 광섬유 제조시스템을 이용하여 단일모드 조건을 만족하는 다양한 종류의 열확산 코어 광섬유가 제작됨을 확인할 수 있었다.

• The Pure and Applied Mathematics
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• v.16 no.2
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• pp.213-225
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• 2009

This paper deals with the existence of positive solutions for a kind of multi-point nonlinear fractional differential boundary value problem at resonance. Our main approach is different from the ones existed and our main ingredient is the Leggett-Williams norm-type theorem for coincidences due to O'Regan and Zima. The most interesting point is the acquisition of positive solutions for fractional differential boundary value problem at resonance. And an example is constructed to show that our result here is valid.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.123.1-123.1
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• 2008

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.202-205
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• 2016

Shipping and logistics safety, security system is strengthening worldwide, the development of shipping and logistics safety security core technology for national security logistics system construction has been carried out. Interest in portable radiation detection device capable detecting gamma rays nuclides is increasing. In this paper, I would like to propose the study of implementation of digital portable radiation detector with the algorithm of temperature compensation.

• Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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• v.4
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• pp.289-317
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• 2001

Das Ziel dieses Aufsatzes liegt darin, Typen und Ursachen der $Ver\"{a}nderungen$ bei den morphologischen Kategorien und den Satz- strukturen zu untersuchen, und die historischen Entwicklungen des Deutschen zusammenfassend darzustellen. In der Sprachentwicklung $m\"{u}ssen$ wir die lebendige Wechselbeziehung zwischen Sprache und Leben beachten. Sprache und Leben sind nicht als zwei verschiedene $Gr\"{o}{\ss}en$ zu betrachten, sondern nur in ihrem gegenseitigen Bedingtsein zu verstehen. Sprache und Leben sind immer in ihren inneren $Zusammenh\"{a}ngen$ zu sehen, $ge\"{a}nderten\;Lebens-\;umst\"{a}nden$ werden sprachliche $Ver\"{a}nderungen$ folgen. Bei den $Ver\"{a}nderungstypen$ wurden einige Ursachen $erw\"{a}hnt$, z. B. die $Abschw\"{a}chung$ der Endungsvokale und die Tendenz der Entwicklung vom synthetischen zum analytischen Satzbau. Eine wirkliche Ursache unter den $Ver\"{a}nderungsfaktoren$ ist der Einfluss der fremden Sprachen auf die deutsche Syntax. Zu den $\"{a}u{\ss}eren$ Ursachen rechnen wir $s\"{a}mliche\;ungew\"{o}hnlich$ verschiedenartigen Impulse, die von der die Sprache umgebenden Umwelt ausgehen. Sprachliche Veranderungen $k\"{o}nnen$ auch innere Ursachen haben. Als innere Ursachen wurden das Prinzip der sprachlichen $\"{O}konomie$, die Tendenz zur emotionalen $Expressivit\"{a}t$, das Streben nach Anschaulichkeit sowie einige $\"{a}sthetisch$ und sozial bedingte $Gr\"{u}nde$ besprochen. In Bezug auf die historischen Entwicklungen des Deutschen wurden die Epochen der Sprachentwicklung in Anlehnung an Hogo Moser(1972) in 5 Epochen, d.h. Vorgeschichte der deutschen Sprache, Altdeutsche Zeit, Mittelalterliches Deutsch, Neudeutsche Zeit und Deutsch der Gegenwart untergliedert, und einige wichtige Entwicklungen des Deutschen in der jeweiligen Epoche zusammengefasst.

• Korean Journal of Crystallography
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• v.11 no.3
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• pp.162-166
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• 2000

KD₂PO₄ single crystals were grown from D₂O with reagent KH₂PO₄ and the crystal structure was determined by X-ray and neutron diffraction methods. The crystals are tetragonal at room temperature, I42d, with lattice parameters of a=7.4633(7), c=6.9785(5) Å and Z=4. Intensity data were collected on an Enraf-nonius CAD4 diffractometer with a graphite monochromated MoK/sub α/ radiation (λ=0.7107Å) and on the neutron four circle single crystal diffractometer with Ge(331) monochromated neutron beam (λ=0.997Å). The structure was refined by full-matrix least-square to final R and wR values of 0.030 and 0.072, respectively, for 204 observed reflections with I>2σ(I) by X-ray diffraction and to final R=0.041 and wR=0.096 for 144 observed relfecdtions by neutron diffraction. The O…O distance of 2.516(4)Å obtained by X-ray diffraction is the same as that of 2.515(4)Å by neutron diffraction. On the other hand, the O-D/H distance of 0.84(4)Å by X-ray diffraction is considerably shorter than 1.029(7) Åby neutron diffraction. Hydrogen and deuterium can be readily distinguished by neutrons. In this crystal 66% of H-positions were substituted by D and the rest 34% occupied by H. The phase transition temperature of DKDP obtained with deuteration levels is f193K. This value agrees fairly well with the result of DSC measurement. The nuclear density distribution by neutron diffraction provides an observation of the disordered state of D/H in KD₂PO₄ at room temperature.

• Journal of the Korean institute of surface engineering
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• v.39 no.2
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• pp.49-56
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• 2006

In this study, the movable flame hardening process of 12Cr steel for a uniform hardness and desirable residual stress have been investigated. For this, the temperature cycles have been controlled accurately as a function of the three processing variables, the flame intensity $I_f$, the scanning velocity $V_s$, and the initial flame holding time $t_h$, where the standard surface temperature $T_{s,\;max}$, was maintained at $960^{\circ}C$. The optimized conditions were $V_s=0.68mn/s\;and\;t_h=67sec$ for the $C_3H_8:O_2\;=\;5:20l/min,\;V_s=0.80mm/s$ and $t_h=56sec$ for the $C_3H_8:O_2=6:24l/min,\;V_s=1.01mm/s\;and\;t_h=48sec$ for the $C_3H_8:O_2=7:28l/min,\;and\;V_s=1.15mm/s$ and $t_h=39sec$ for the $C_3H_8:O_2$=8:32 l/min. The optimally flame-hardened surface exhibited uniform distributions of the hardness and residual compressive stress over the treated area with moderate levels of $470{\sim}490HV_{0.2}$in hardness and $-300{\sim}-450MPa$ in residual stress, which were acceptable on the basis of the acceptance criteria of Siemens AG-KWU and GE Power Generation Engineering.