Metal-Free Room-Temperature Vulcanization of Silicones via Borane Hydrosilylation

Sample, Caitlin S.,Lee, Sang-Ho,Li, Shaoguang,Bates, Morgan W.,Lensch, Valerie,Versaw, Brooke A.,Bates, Christopher M.,Hawker, Craig J. American Chemical Society 2019 Macromolecules Vol.52 No.19

<P>Vulcanization of silicone networks from commercially available linear poly(dimethyl-<I>co</I>-methylhydro)siloxane (PMHS) and α-diketones was achieved using metal-free borane hydrosilylation at room temperature. The Lewis acid catalyst, tris(pentafluorophenyl)borane (B(C<SUB>6</SUB>F<SUB>5</SUB>)<SUB>3</SUB>), efficiently cross-linked PMHS at minimal catalyst loadings (200-1000 ppm) to produce polymer networks with mechanical properties, thermal stability, and optical clarity rivaling that achieved from traditional platinum catalysis. Variation of the starting PMHS structure is shown to influence the final characteristics of the network. Increasing molar mass of the PMHS chain results in a higher thermal decomposition temperature, while increasing mole fractions of Si-H moieties along the backbone increase the cross-linking density and the attendant Shore hardness. The degradation behavior of the networks was investigated, with the borane-vulcanized samples showing rapid dissolution upon exposure to acid and high stability to neutral and basic conditions. Functional networks bearing halide and vinyl groups could also be prepared via a preliminary reaction of PMHS with an appropriate monoketone, providing a general and versatile strategy for network derivatization with the potential for postvulcanization functionalization being subsequently demonstrated via thiol-ene click chemistry.</P> [FIG OMISSION]</BR>

자기회귀 과정에서의 축차확률비 검정에 의한 오류확률과 기대표본크기

최기헌,Error Probability and Expected Sample Sizes for SPRT in the Auto Regressive Process 高麗大學校統計硏究所 1989 應用統計 Vol.4 No.1

통계분석에 있어서 축차적 방법(sequential method)를 소개하는 데는 크게 두 가지 이유가 있다. 하나는 고정표본 해(fixed sample solution)를 가지는 문제들을 좀더 효율적으로 풀기 위한 것이고, 다른 하나는 고정표본 해가 존재하지 않는 경우이다.

전자선원을 이용한 CINEMA위성의 플라즈마 입자 검출기의 기능 검증

서용명,전종호,박성하,김용호,전제헌,이정규,J.G. Sample,T. Immel,R.P. Lin,진호,이동훈,선종호 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.4

경희대학교가 제작한 초소형 위성 TRiplet Ionospheric Observatory-Cubesat for Ion, Neutral, Electron and MAgnetic field (TRIO-CINEMA)는 지구 자기권에 존재하는 플라즈마 입자와 자기장의 계측을 주요 목적으로 하는 과학 임무 위성이다. 위성의 주 탑재체인 SupraThemal Electron, Ion and Neutral (STEIN)은 solid state 실리콘 반도체를 사용하여 전자, 중성자 및 양성자를 동시에 검출 할 수 있는 플라즈마 입자 검출기 이다. STEIN은 4~200 keV의 에너지 대역과 1 keV FWHM의 분해능을 갖으며, 정전기 편향판을 사용하여 중성자와 대전입자를 분류하여 검출한다. 본 연구에서는 전자 선원을 사용하여 CINEMA 위성의 주 탑재체인 STEIN의 입자 검출, 대전 입자의 휨, 에너지 값 보정, 기하계수 등을 검증하기 위한 시험을 수행 하였다. TRIO-CINEMA is a space science mission consisting of three identical 3U CubeSats to provide stereo Energetic Neutral Atom (ENA) imaging of the ring current, multi-point in-situ measurement of supra thermal electrons and ions, and measurement of magnetic fields in Low Earth Orbit (LEO). The primary payload STEIN measures the particles in the range of ~4-200 keV with 1 keV FWHM energy resolution and is able to distinguish electrons, ions, and neutrals by applying electric field in the entrance aperture. In this research, we performed a test to verify the functions such as particle detection, deflection by electrostatic field, energy scale, geometric factor of STEIN instrument by applying electron beam source.

FPGA를 이용한 CINEMA 위성의 On-Board-Computer와 탑재체간의 인터페이스 개발

서용명,채규성,윤세영,B. Mochizuki,D. Clarino,N. Yeung,J.G. Sample,T. Immel,R.P. Lin,진호,이동훈,선종호 한국항공우주학회 2012 한국항공우주학회 학술발표회 논문집 Vol.2012 No.11

초소형 위성 큐브셋은 개발기간의 단축과 신뢰성 향상 위해 표준화된 플랫폼을 만족하는 상용부품을 사용하여 항공전자부를 구성하여 사용하는 반면, 위성의 임무를 수행하는 탑재체는 큐브셋의 표준화된 인터페이스와 달리 제작되는 경우가 있다. 본 연구에서는 FPGA를 이용하여 경희대학교에서 제작한 초소형 위성 CINEMA (Cubesat for Ion, Neutral, Electron and MAgnetic field)의 주 컴퓨터와 탑재체 간인터페이스를 구성하는 모듈을 제작하였다. 본 인터페이스 모듈의 FPGA는 위성의 주 컴퓨터와 탑재체간의 통신 인터페이스를 제공하고, 주 컴퓨터의 연산의 부하를 줄여주어 데이터 처리 효율을 높여준다. 또한 본 모듈은 탑재체가 요구하는 다양한 전원을 제공하며, 초소형 위성에 자주 사용되는 소형의 회로들을 내장하고 있다. The standard spacecraft, known as CubeSat, utilizes Commercial-Off-The Shelf (COTS) electronics to build the bus avionics, while payloads are usually built according to a particular method that does not conform to the standard. Particularly in the CubeSat for Ions, Neutrals, Electrons, and Magnetic fields (CINEMA) spacecraft, Instrument Interface module between the on-board-computer (OBC) and the mission payloads is developed to provide required communication and power interfaces. The module mainly consists of FPGA to provide communication interfaces and to support limited computing power of the OBC and peripheral sub-circuits that are frequently used in small spacecraft.

Energetic, ∼5-90 keV neutral atom imaging of a weak substorm with STEREO/STE : STEREO/STE ENA IMAGING OF WEAK SUBSTORM

Wang, Linghua,Lin, R. P.,Parks, G. K.,Brandt, P. C.,Roelof, E. C.,Sample, J. G.,Eastwood, J. P.,Larson, D. E.,Curtis, D. W.,Luhmann, J. G. American Geophysical Union 2010 Geophysical research letters Vol.37 No.8

Modeling of Energetic Neutral Atom (ENA) Emissions During a Magnetic Storm for CINEMA/TRIO

이은상,권혁진,박종선,선종호,진호,김관혁,이동훈,Lee, Ensang,Kwon, Hyuk-Jin,Park, Jong-Sun,Seon, Jongho,Jin, Ho,Kim, Khan-Hyuk,Lee, Dong-Hun,Wang, Linghua,Lin, Robert P.,Parks, George K.,Sample, John,Roelof, Edward C. 한국천문학회 2012 天文學會報 Vol.37 No.2

Energetic neutral atoms (ENAs) are emitted by charge exchange collisions between energetic ions and cold neutral atoms. ENAs can be used as an alternative measure of the energetic ions in the source region because they maintain the energy and pitch angle of the source energetic ions. In the present study we present simulation results of the ENA emissions during a magnetic storm to be measured by the STEIN instrument onboard the CINEMA/TRIO satellites. The CINEMA/TRIO mission consists of three identical cubesats with low-altitude orbits. The STEIN instrument onboard each cubesat can measure ENAs with energies from ~4 keV to ~20 keV as well as suprathermal electrons and ions. The measurement of ENA emissions from ring current by STEIN is simulated using the models for energetic ring current ions and geocoronal neutral atoms. Especially we will discuss about the energy spectrum of the ENAs and the effect of transient variations of the ring current.

Informal Settlers, Government Officials, and Disaster Vulnerability - Experience from the Philippines -

Janet Dilling,Ralph Brower,Judith Cuadra,Malaika Samples 위기관리 이론과 실천 2014 Journal of Safety and Crisis Management Vol.4 No.1

Informal, marginal settlements in the developing world are not only increasing but worsening in the face of overpopulation, economic instability and unprecedented climate variance. In the Philippines, cities are powerful magnets for rural populations lacking local opportunities and who seek to achieve prosperity for their immediate and future generations. These centers of “possibilities” however fail to provide basic needs and services for increasing numbers of internal immigrants. UN Habitat reports that as of 2012, at least 63% of the 92 million Filipinos live in urban centers such as Metro Manila, or what is officially called the National Capital Region (NCR). An estimated 3.1 million of them lack secure land tenure and 2.7 are informal settlers living in slums (Karaos, Nicolas, Rabacal et al, 2012). The Philippines, like many island countries, suffers from land deficit; housing is not only difficult but economically unfeasible for the urban poor. Thus, the urban poor are unconsciously driven to areas otherwise unsuitable for housing. These danger zones are prone to flooding, seismic activity and landslides. Living in these areas exposes informal settlers to a vicious repeat cycle of destruction and loss of life. What is the source of a community’s resistance to relocate in the face of continuing risk? Some studies suggest that the place that we call home is not just a point in a geographical setting. Communities develop shared values and shared identity with place (Hewitt, K 1997). The Filipino government is currently on a crusade to address this problem by planning to relocate the individuals at high risk; they have certainly found opposition from the settlers. But, what are the specific factors that impede successful relocation? In this study we attempt to answer this question by looking at the cultural, social, economic, political factors and interactive dynamics that influence the way people decide where to live. The findings presented in this paper correspond to field work in the Rizal Province and its Municipality of San Mateo, more specifically concerning those living in Barangay Banaba. Hopefully the collection and analysis of such data could contribute towards a better understanding of the individual at risk, formulation of more effective disaster reduction strategies, and greater discussion of the situation and needs of these communities.