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Observation of a multiferroic critical end point.
Kim, Jae Wook,Haam, S Y,Oh, Y S,Park, S,Cheong, S-W,Sharma, P A,Jaime, M,Harrison, N,Han, Jung Hoon,Jeon, Gun-Sang,Coleman, P,Kim, Kee Hoon National Academy of Sciences 2009 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.106 No.37
<P>The study of abrupt increases in magnetization with magnetic field known as metamagnetic transitions has opened a rich vein of new physics in itinerant electron systems, including the discovery of quantum critical end points with a marked propensity to develop new kinds of order. However, the electric analogue of the metamagnetic critical end point, a 'metaelectric' critical end point, has been rarely studied. Multiferroic materials wherein magnetism and ferroelectricity are cross-coupled are ideal candidates for the exploration of this novel possibility using magnetic-field (H) as a tuning parameter. Herein, we report the discovery of a magnetic-field-induced metaelectric transition in multiferroic BiMn(2)O(5), in which the electric polarization (P) switches polarity along with a concomitant Mn spin-flop transition at a critical magnetic field H(c). The simultaneous metaelectric and spin-flop transitions become sharper upon cooling but remain a continuous cross-over even down to 0.5 K. Near the P = 0 line realized at mu(0)H(c) approximately 18 T below 20 K, the dielectric constant (epsilon) increases significantly over wide field and temperature (T) ranges. Furthermore, a characteristic power-law behavior is found in the P(H) and epsilon(H) curves at T = 0.66 K. These findings indicate that a magnetic-field-induced metaelectric critical end point is realized in BiMn(2)O(5) near zero temperature.</P>
Two-Dimensional Nanosheets Produced by Liquid Exfoliation of Layered Materials
Coleman, J. N.,Lotya, M.,O'Neill, A.,Bergin, S. D.,King, P. J.,Khan, U.,Young, K.,Gaucher, A.,De, S.,Smith, R. J.,Shvets, I. V.,Arora, S. K.,Stanton, G.,Kim, H.-Y.,Lee, K.,Kim, G. T.,Duesberg, G. S.,H American Association for the Advancement of Scienc 2011 Science Vol.331 No.6017
<P>If they could be easily exfoliated, layered materials would become a diverse source of two-dimensional crystals whose properties would be useful in applications ranging from electronics to energy storage. We show that layered compounds such as MoS(2), WS(2), MoSe(2), MoTe(2), TaSe(2), NbSe(2), NiTe(2), BN, and Bi(2)Te(3) can be efficiently dispersed in common solvents and can be deposited as individual flakes or formed into films. Electron microscopy strongly suggests that the material is exfoliated into individual layers. By blending this material with suspensions of other nanomaterials or polymer solutions, we can prepare hybrid dispersions or composites, which can be cast into films. We show that WS(2) and MoS(2) effectively reinforce polymers, whereas WS(2)/carbon nanotube hybrid films have high conductivity, leading to promising thermoelectric properties.</P>
the CONCORD Working Group,Matz, M.,Coleman, M.P.,Sant, M.,Chirlaque, M.D.,Visser, O.,Gore, M.,Allemani, C. Academic Press 2017 Gynecologic oncology Vol.144 No.2
Objective: Ovarian cancers comprise several histologically distinct tumour groups with widely different prognosis. We aimed to describe the worldwide distribution of ovarian cancer histology and to understand what role this may play in international variation in survival. Methods: The CONCORD programme is the largest population-based study of global trends in cancer survival. Data on 681,759 women diagnosed during 1995-2009 with cancer of the ovary, fallopian tube, peritoneum and retroperitonum in 51 countries were included. We categorised ovarian tumours into six histological groups, and explored the worldwide distribution of histology. Results: During 2005-2009, type II epithelial tumours were the most common. The proportion was much higher in Oceania (73.1%), North America (73.0%) and Europe (72.6%) than in Central and South America (65.7%) and Asia (56.1%). By contrast, type I epithelial tumours were more common in Asia (32.5%), compared with only 19.4% in North America. From 1995 to 2009, the proportion of type II epithelial tumours increased from 68.6% to 71.1%, while the proportion of type I epithelial tumours fell from 23.8% to 21.2%. The proportions of germ cell tumours, sex cord-stromal tumours, other specific non-epithelial tumours and tumours of non-specific morphology all remained stable over time. Conclusions: The distribution of ovarian cancer histology varies widely worldwide. Type I epithelial, germ cell and sex cord-stromal tumours are generally associated with higher survival than type II tumours, so the proportion of these tumours may influence survival estimates for all ovarian cancers combined. The distribution of histological groups should be considered when comparing survival between countries and regions.
the CONCORD Working Group,Matz, M.,Coleman, M.P.,Carreira, H.,Salmeron, D.,Chirlaque, M.D.,Allemani, C. Academic Press 2017 Gynecologic oncology Vol.144 No.2
Objective: Ovarian cancer comprises several histological groups with widely differing levels of survival. We aimed to explore international variation in survival for each group to help interpret international differences in survival from all ovarian cancers combined. We also examined differences in stage-specific survival. Methods: The CONCORD programme is the largest population-based study of global trends in cancer survival, including data from 60 countries for 695,932 women (aged 15-99years) diagnosed with ovarian cancer during 1995-2009. We defined six histological groups: type I epithelial, type II epithelial, germ cell, sex cord-stromal, other specific non-epithelial and non-specific morphology, and estimated age-standardised 5-year net survival for each country by histological group. We also analysed data from 67 cancer registries for 233,659 women diagnosed from 2001 to 2009, for whom information on stage at diagnosis was available. We estimated age-standardised 5-year net survival by stage at diagnosis (localised or advanced). Results: Survival from type I epithelial ovarian tumours for women diagnosed during 2005-09 ranged from 40 to 70%. Survival from type II epithelial tumours was much lower (20-45%). Survival from germ cell tumours was higher than that of type II epithelial tumours, but also varied widely between countries. Survival for sex-cord stromal tumours was higher than for the five other groups. Survival from localised tumours was much higher than for advanced disease (80% vs. 30%). Conclusions: There is wide variation in survival between histological groups, and stage at diagnosis remains an important factor in ovarian cancer survival. International comparisons of ovarian cancer survival should incorporate histology.
Kim, M. E.,Gorman, G. M.,Cho, N. M.,Kong, K. S.,Champaneria, C. N.,Greene, J. E.,Bruckner, C. L.,Walsworth, C. R.,Do, V. A.,Coleman, D. W.,Hew, P. R.,Chung, S. C.,Jung, W.,Seo, H. C.,Hwang, Y. I.,Chu, 대한전자공학회 1993 ICVC : International Conference on VLSI and CAD Vol.3 No.1
This paper .discusses the GaAs HBT device and IC technology and its application to commercial wireless communication systems in the 0.8-6 GHz frequency range. Key performance/cost advantages of the GaAs HBT previously established over silicon bipolar and GaAs MESFET in this frequency regime are now being applied to critical RF front-end requirements of wireless voice and data communication systems. GaAs HBT components developed far such wireless systems include small-signal .and power functions which offer combinations of higher gain-bandwidth, higher efficiency, lower distortion, wider dynamic range and simpler design implementations. GaAs HBT/IC fabrication technology, device/IC performance and system applications are discussed.