نتایج جستجو برای: diamond

تعداد نتایج: 20974  

2015
Chengzhi Luo Xiang Qi Chunxu Pan Wenge Yang

In this article, we report a new route to synthesize diamond by converting "solid" carbon nanofibers with a Spark Plasma Sintering system under low temperature and pressure (even at atmospheric pressure). Well-crystallized diamond crystals are obtained at the tips of the carbon nanofibers after sintering at 1500 °C and atmospheric pressure. Combining with scanning electron microscopy, transmiss...

2018
Yuri N. Palyanov

This special issue is intended to serve as a multidisciplinary forum covering broad aspects of the science, technology, and application of synthetic and natural diamonds. This special issue contains 12 papers, which highlight recent investigations and developments in diamond research related to the diverse problems of natural diamond genesis, diamond synthesis and growth using CVD and HPHT tech...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2002
Chih-Shiue Yan Yogesh K Vohra Ho-Kwang Mao Russell J Hemley

Diamond possesses extraordinary material properties, a result that has given rise to a broad range of scientific and technological applications. This study reports the successful production of high-quality single-crystal diamond with microwave plasma chemical vapor deposition (MPCVD) techniques. The diamond single crystals have smooth, transparent surfaces and other characteristics identical to...

2006
Manabu Iwai Sadao Sano Weili Pan Kenji Itagaki Yoshihiko Murakami Mei Wang Tetsutaro Uematsu Kiyoshi Suzuki

INTRODUCTION In order to realize successful fine and precise EDM, it is important to minimize the wear of the electrode under the condition of very small pulse duration. To cope with this issue, the authors focused attention on the electrically conductive CVD diamond (EC-CVD diamond here after) having very high thermal conductivity, and have already shown that an extremely low wear machining co...

2016
Jiangwei Liu Hirotaka Ohsato Xi Wang Meiyong Liao Yasuo Koide

The lack of large-area single-crystal diamond wafers has led us to downscale diamond electronic devices. Here, we design and fabricate a hydrogenated diamond (H-diamond) triple-gate metal-oxide-semiconductor field-effect transistor (MOSFET) to extend device downscaling and increase device output current. The device's electrical properties are compared with those of planar-type MOSFETs, which ar...

Journal: :Nature communications 2015
Gregory T Hohensee R B Wilson David G Cahill

The thermal conductance of interfaces between metals and diamond, which has a comparatively high Debye temperature, is often greater than can be accounted for by two-phonon processes. The high pressures achievable in a diamond anvil cell (DAC) can significantly extend the metal phonon density of states to higher frequencies, and can also suppress extrinsic effects by greatly stiffening interfac...

Journal: :Journal of nanoscience and nanotechnology 2004
A S Barnard S P Russo I K Snook

Recent advances in the fabrication and characterization of semiconductor and metallic nanowires are meeting the high expectations of nanotechnolgists. Although diamond has remarkable electronic and chemical properties, development of diamond nanowires has been slow, while the development of carbon nanotube-based technologies continues at a furious pace. Recently, the theoretical and experimenta...

2013
Jungwan Cho Zijian Li Elah Bozorg-Grayeli Takashi Kodama Daniel Francis Felix Ejeckam Firooz Faili Mehdi Asheghi Kenneth E. Goodson

High-power operation of AlGaN/GaN high-electronmobility transistors (HEMTs) requires efficient heat removal through the substrate. GaN composite substrates, including the high-thermal-conductivity diamond, are promising, but high thermal resistances at the interfaces between the GaN and diamond can offset the benefit of a diamond substrate. We report on measurements of thermal resistances at Ga...

2009
Alison Mainwood

Marshall Stoneham London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, 17–19 Gordon Street, London WC1H 0AH, UK Natural diamond has been valued for its appearance and mechanical properties for at least two thousand years. As a gem stone diamond is unsurpassed. However, scientific work, especially in the last 20 years, has demonstrated that diamond...

Journal: :The Annals of occupational hygiene 2011
Gill Nelson Jill Murray James Ian Phillips

OBJECTIVES Asbestos is associated with South African diamond mines due to the nature of kimberlite and the location of the diamond mines in relation to asbestos deposits. Very little is known about the health risks in the diamond mining industry. The objective of this study was to explore the possibility of asbestos exposure during the process of diamond mining. METHODS Scanning electron micr...

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