Transmission Properties of Cryogenic Twisted Pair Filters

송운,Mushtaq Rehman,류상완,정연욱 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.6

We fabricated a cryogenic low pass filter that consists of twisted pairs of manganin wires wrapped in copper tape and measured its transmission characteristics at frequencies up to 18 GHz. The dependence of the microwave transmission characteristics on the filter length was studied, which showed that a filter of length 1.0 m had a 70-dB attenuation at 1 GHz. We also studied the dependence of common- and differential-mode transmission on the number of twists per unit length and found that the number of twists per unit length affects differential-mode transmission but not common-mode transmission. Because the shielded twisted pair filter is more compact than a conventional copper powder filter, it can solve the space and thermal load issues when many cables are required for precision electronic transport experiments at low temperatures.

제이종 초전도체에서의 자속잡음측정

송운 空軍士官學校 1996 論文集 Vol.37 No.-

직접적으로 자속의 움직임을 관찰하여 제이종 초전도체인 niobium 박막의 자속잡음을 측정하였다. 상용의 rf SQUID(Superconducting Quantum Interference Device)를 사용하여 시료에 걸어준 전류와 자기장의 변화에 따른 자속의 움직임을 관찰하였다. 실험에 사용한 시료는 rf sputtering으로 제작하였으며 noise power spectra를 관찰한 결과는 흘려준 전류의 값에 따라 1/f 잡음을 보일 때와 Lorentzian을 보일 때가 있음을 확인하였다. 움직이는 자속묶음의 크기와 속도를 실험결과에서 계산할 수 있었고, 관찰한 1/f 잡음은 자속의 속도분포를 도입함으로써 설명할 수 있었다.

Oscillation of Critical Current by Gate Voltage in Cooper Pair Transistor

송운,정연욱,김남,Song, W.,Chong, Y.,Kim, N. The Korean Superconductivity Society 2010 Progress in superconductivity Vol.11 No.2

We measured the critical current of a Cooper pair transistor consisting of two Josephson junctions and a gate electrode. The Cooper pair transistors were fabricated by using electron-beam lithography and double-angle evaporation technique. The Gate voltage dependence of critical current was measured by observing voltage jumps at various gate voltages while sweeping bias current. The observed oscillation was 2e-periodic, which shows the Cooper pair transistor had low level of quasiparticle poisoning.

Local-Gating Carbon-Nanotube Transistor with Poly-Si Bottom Gates

송운,Sunkyung Moon,이순걸,김진희 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.4

A carbon nanotube field-effect transistor (CNFET) over poly-Si local gates was fabricated. The highly-doped poly-Si local gates were fabricated on top of a SiO2 layer and an individual single-wall carbon nanotube was grown over the ploy-Si gates by using chemical vapor deposition. The transport characteristics of the CNFETs were measured at low temperatures. The gate response showed typical p-type FET characteristics with both global back and local bottom gates. The gate coupling of the local gates were comparable to or even greater than that of the global back gate. By applying appropriate gate bias voltages, we could achieve complete depletion of the carriers in the conduction channel.

문예 (文藝) : 증일본승원광원길서 (贈日本僧圓光元佶書) , ( 덕천 (德川) ) 가강장자 (家康長子) 유의선학 (有意禪學) 구어재근 (求語再勤) 급시지 (伋示之) , 차원길운 (次元佶韻) / 일소거사 (逸素居士) 선 (選) , 송운대사 사명당 (松雲大師 泗溟堂)

일소거사(선),송운대사 불교진흥회 1916 불교진흥회월보 Vol.1 No.6

HT-29 인체 대장암세포에서 유니테인 및 심층수염 미네랄의 In Vitro 항암효과

이경화,송운서,이연준,반연예,함석찬,박건영 한국식품영양과학회 2023 한국식품영양과학회지 Vol.52 No.1

본 연구에서는 유니테인(콩, 홍삼과 진피의 발효물) 및 심층수염 미네랄(deep seawater salt minerals, DSM)을 이용하여 기능성 발효제품을 제조했을 때 항암 및 항염증 기능성의 효과를 확인하였다. 유니테인의 경우 비발효 유니테인보다 높은 HT-29 암세포 성장 억제율을 보였으며, 단독 DSM 또한 0.2 mg/mL 농도에서 32.68±1.99%의 높은 암 억제율을 보였다. Cell cycle arrest 관련 유전자인 p53 및 p21에서 Con군에 비해 다른 군 모두 유의적으로 높은 유전자 발현을 보였으며, 특히 유니테인 및 고농도 DSM이 혼합된 UH의 경우 p53에서 Con군보다 10배가량 증가할 정도로 가장 높은 수준을 보였다(P<0.05). Apoptosis 관련 유전자인 Bim, Bad, Bak, caspase 3 및 caspase 9 유전자 발현은 모두 Con 및 UU보다 Uni, UL 및 UH에서 유의적으로 높은 수준을 보였다. 다만 Bax에서는 UU의 발현량이 Uni 및 UL과 비슷하게 나타났으나 UH의 경우 Con군에 비해 3배가량 높은 수준을 보였다. Anti-apoptosis인 Bcl-2 유전자 또한 UH군이 가장 낮은 수준을 보여 모든 그룹 중 UH군이 가장 높은 대장암 억제 효과를 나타내었다(P<0.05). 염증 관련 NF-κB p50, NF-κB p65 및 COX-2의 유전자 발현은 Con군보다 모든 그룹에서 유의적으로 감소했다(P<0.05). 따라서 비발효된 유니테인보다 발효과정을 거쳐 제조된 유니테인의 경우 apoptosis를 현저히 증가시키며 COX-2 및 NF-κB 발현을 감소시켜 대장암 및 염증을 억제한 것으로 보인다. 또한 유니테인에 추가된 DSM 천연물 혼합으로 항암 및 항염증 기능성이 증진되었다.

初期大乘經典에 나타난 佛身說

廉点子(松雲) 한국불교학회 2008 韓國佛敎學 Vol.50 No.-

This article has attempted to examine briefly about the Buddha-kāya(Buddha's Body) theory in early Mahāyāna Sūtras. As each school has it's own unique formation and system, it is observed that there are differences in emphasized phases by each scripture in the theory of Buddha-kāya. The theory of Buddha-kāya had been existing before Mahāyāna buddhist texts. But in early texts, it emphasizes on the admiring greatness of spiritually awake Śakyamuni-Buddha being one with truth of immortality. Even though Dharma oriented thought is unsatisfactory for an object of faith, because Dharma that Śakyamuni realized was heard and accepted through personality as Śakyamuni it is regarded that comprehension about Dharma-kāya had been included. Therefore, There is no Dharma-kāya oriented view of the Buddha's body as in Mahāyāna Sūtras, but it could be seen that Rūpa-kāya oriented view of the Buddha's body was strong. Through Surveying historical development of the theory of Buddha- kāya from the time of fundamental Buddhism to Abhidharma Buddhism as coming to 18 schools. The latter propositions to emphasizing a historical source rather than realistic standpoint, had recognized a boundary by strict distinguishing between Dharma-kāya and Rūpa-kāya. In the Abhidharma Buddhism, the Theravāda and Sarvāstivāda had their theory of Buddha-kāya that is to the real embracement place based on highlighting Dharma-kāya, in contrast to the Mahāsaṃghika had emphasizing on religious idealized Dharma-kāya. Finally, through various improvement of Mahāsaṃghika more emphasizing on idealized Buddha as a super-historic existence, it became Dharma-oriented theory of Dharma-kāya, it is established as the early Mahāyāna buddhism's Buddha-kāya. However, the Buddha-kāya concept improved along with development of dogmatic theology was Buddha's rūpa-kāya who existed historically, but we can't say that there was no comprehension about Buddha-kāya. And when 18 schools, as we make comment on Rūpa-kāya and Buddha-kāya, it was mainly rūpa-kāya. This study has shown that we observed that theory of Buddha-kāya regarding Dharma-kāya and Rūpa-kāya, as entering to Mahāyāna Buddhism period, was moved to Dharma-kāya oriented. 初期大乘經典에 나타난 佛身說은 法身중심의 二身說이다. 法身중심의 二身說은 원시경전에서는 不滅의 진리와 일체가 된 깨달은 석존에 대한 위대성을 찬탄하는 데에 역점을 두고 있다. 이러한 法중심의 사고는 신앙의 대상으로서 만족되지 못하였지만 석존이라는 인격을 통하여 석존이 깨달은 법을 듣고 받아 들였기 때문에 법신에 대한 이해는 포함되어 있었다고 보나 대승경전에서와 같은 法身중심의 佛身觀에는 이르지 못한 色身 중심의 佛身說의 성격이 강했다고 볼 수 있다. 大乘初期經典에서는 法身중심으로 나타나는데 諸佛의 本質論으로서 佛身說 내지 法 그 자체를 佛身으로 보려는 法身사상은 강조되지 않았으며 諸佛의 통일체로서 久遠釋迦佛의 本佛사상과 자비방편으로 大悲誓願의 救濟佛사상을 『無量壽經』과 『法華經』을 중심으로 살펴보았다. 또한 眞如法身을 강조하는 것이 분명하게 나타나는 『金剛經』을 살펴보면 본질적인 불타와 현상적인 불타를 구별하여 肉身의 불타였던 석존을 숭배하는 것에서부터 佛塔에 모셔진 석존의 유골을 불타의 신체라고 생각했던 불탑 숭배자의 불탑 신앙을 비판하고, 불타의 지혜를 나타내는 般若波羅蜜이야말로 진실한 佛身이라고 말하고 있다. 『維摩經』에서는 菩提의 法을 중심으로 佛身을 생각하고 있으며, 法身의 세계로 가려면 阿耨多羅三藐三菩提心을 일으켜야 하는데 小乘的 生身佛身說을 보다 넓은 차원으로 이끌어 내어 大乘佛敎의 성숙한 佛身說을 수립하게 된다. 十方遍滿의 佛身說로서 『華嚴經』의 佛身說은 十佛世界ㆍ十身具足의 佛身說로서 法身佛과 應化佛이 圓融自在한 佛身說로 나타난다.

Al 식각정지층을 이용한 Nb-based SNS 조셉슨 접합의 제조공정

최정숙,박정환,송운,정연욱,Choi, J.S.,Park, J.H.,Song, W.,Chong, Y. 한국초전도학회 2011 Progress in superconductivity Vol.12 No.2

We report our efforts on the development of Nb-based non-hysteretic Josephson junction fabrication process for quantu device applications. By adopting and modifying the existing Nb-aluminum oxide tunnel junction process, we develop a process for non-hysteretic Josephson junction circuits using metal-silicide as metallic barrier material. We use sputter deposition of Nb and $MoSi_2$, PECVD deposition of silicon oxide as insulator material, and ICP-RIE for metal and oxide etch. The advantage of the metal-silicide barrier in the Nb junction process is that it can be etched in $SF_6$ RIE together with Nb electrode. In order to define a junction area precisely and uniformly, end-point detection for the RIE process is critical. In this paper, we employed thin Al layer for the etch stop, and optimized the etch condition. We have successfully demonstrated that the etch stop properties of the inserted Al layer give a uniform etch profile and a precise thickness control of the base electrode in Nb trilayer junctions.

10의 -10승 수준에서 조셉슨 전압표준기 불확도 평가

김규태,김문석,정연욱,김완섭,송운,Kim, K.T.,Kim, M.S.,Chong, Y.,Kim, W.S.,Song, W. The Korean Superconductivity Society 2007 Progress in superconductivity Vol.9 No.1

The most recent improvement in the 10 V array system was carried out with focusing on noise reduction. We have evaluated the uncertainty of the 10 V Josephson array system after the improvement. The uncertainty evaluation of 10 V standard included a comparison with a programmable Josephson array system at 1 V. Every contribution to the measurement uncertainty was evaluated in the level of $10^{-10}$. The estimated combined uncertainty was found to be approximately $10^{-9}$ at 10 V, which was limited only by the indirect verifying method. In the near future, a direct comparison with another 10 V Josephson voltage standard is expected to be carried out to provide more accurate uncertainty evaluation for the KRISS Josephson voltage standard.

Design of an Antireflection Coating for High-efficiency Superconducting Nanowire Single-photon Detectors

최지만,최가현,이선경,박기복,송운,이동훈,정연욱 한국광학회 2021 Current Optics and Photonics Vol.5 No.4

We present a simulation method to design antireflection coating (ARCs) for fiber-coupled superconducting nanowire single-photon detectors. Using a finite-element method, the absorptance of the nanowire is calculated for a defined unit-cell structure consisting of a fiber, ARC layer, nanowire absorber, distributed Bragg reflector (DBR) mirror, and air gap. We develop a method to evaluate the uncertainty in absorptance due to the uncontrollable parameter of air-gap distance. The validity of the simulation method is tested by comparison to an experimental realization for a case of single-layer ARC, which results in good agreement. We show finally a double-layer ARC design optimized for a system detection efficiency of higher than 95%, with a reduced uncertainty due to the air-gap distance.