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991.
On the shoulders of students? The contribution of PhD students to the advancement of knowledge 总被引:1,自引:0,他引:1
Using the participation in peer reviewed publications of all doctoral students in Quebec over the 2000–2007 period, this paper
provides the first large scale analysis of their research effort. It shows that PhD students contribute to about a third of
the publication output of the province, with doctoral students in the natural and medical sciences being present in a higher
proportion of papers published than their colleagues of the social sciences and humanities. Collaboration is an important
component of this socialization: disciplines in which student collaboration is higher are also those in which doctoral students
are the most involved in peer-reviewed publications. In terms of scientific impact, papers co-signed by doctorate students
obtain significantly lower citation rates than other Quebec papers, except in natural sciences and engineering. Finally, this
paper shows that involving doctoral students in publications is positively linked with degree completion and ulterior career
in research. 相似文献
992.
Lei ZhengXiaodong Su Jun FanYajie Chen Xiaoluan YangLixing You Vincent G. Harris 《Thin solid films》2012,520(9):3651-3656
Control of the in-plane crystallographic orientation of YBa2Cu3O7 − x (YBCO) films on (100) MgO substrates is of significant application value due to the selective enhancement of superconducting properties. In the present work, the preparation, crystallographic and superconducting properties of YBCO films deposited on MgO substrates are reported. Crystallographic in-plane orientation was realized by means of tailoring the pulsed laser deposition conditions and the use of interfacial buffering structures. Superconductiong properties were measured for films having different in-plane orienations. The results indicate that the 0° in-plane oriented films showed the highest current density of 1.62 MA/cm2 that was attributed to the elimination of high-angle grain boudaries. Additionally, the growth mechanism of YBCO films was discussed in terms of crystallographic and thermodynamic theory. 相似文献
993.
Ultra acidic strong cation exchange enabling the efficient enrichment of basic phosphopeptides 总被引:1,自引:0,他引:1
Hennrich ML van den Toorn HW Groenewold V Heck AJ Mohammed S 《Analytical chemistry》2012,84(4):1804-1808
We present a straightforward method to enrich phosphopeptides with multiple basic residues, an under-represented class in common enrichment strategies. Our method is based on a two-dimensional strong cation exchange (SCX) strategy, operating at two different acidic pHs, enabling both separation and enrichment of different classes of phosphopeptides. The principle of enrichment is based on the change of net charge of phosphorylated peptides under strong acidic conditions in the second SCX, whereas the net charge of regular peptides remains unchanged, thus enabling separation based on net charge. Application of our tandem SCX approach to a modest amount of human cells allowed the identification of over 10,000 unique "basic" phosphopeptides of which many represent putative targets of basophilic kinases. 相似文献
994.
A. Hikavyy W. VanherleB. Vincent J. DekosterH. Bender A. MoussaL. Witters T. HoffmanR. Loo 《Thin solid films》2012,520(8):3179-3184
Growth of high (above 40%) Ge content SiGe by applying silane and dichlorosilane as Si precursors on (110) Si is investigated. In the case of silane based processes Ge concentration is ~ 20% higher, whereas for dichlorosilane based processes it is ~ 30% lower on (110) Si compared to (100) Si. The morphology of the grown layers is found to be dependent on Ge concentration, layer thickness and process temperature. Use of optimized deposition parameters and adequate thickness results in high quality strained SiGe layers. Integration of high Ge content SiGe layers in multiple gate filed-effect transistor structures shows the expected differences in Ge content on the different Si planes forming Si fin. These differences can be avoided by adjusting the fin orientation on the Si wafer resulting in equal planes on the fin's top and sidewalls. When the investigated SiGe layers are incorporated in the buried channel field effect transistor structures on (110) Si wafers a significant thickening at the active windows edge is observed. It is speculated that this effect is connected with elastic SiGe relaxation caused by a non optimized process temperature. 相似文献
995.
Farahani RD Dalir H Le Borgne V Gautier LA El Khakani MA Lévesque M Therriault D 《Nanotechnology》2012,23(8):085502
This paper deals with the design and microfabrication of two three-dimensional (3D) freestanding patterned strain sensors made of single-walled carbon nanotube (SWCNT) nanocomposites with the ultraviolet-assisted direct-write (UV-DW) technique. The first sensor consisted of three nanocomposite microfibers suspended between two rectangular epoxy pads. The flexibility of the UV-DW technique enables the sensor and its housing to be manufactured in one monolithic structure. The second sensor was composed of a nanocomposite network consisting of four parallel microsprings, which demonstrates the high capability of the technique when compared to conventional photolithographic technologies. The performances of the sensors were assessed under tension and compression, respectively. The sensors' sensitivities were evaluated by correlating their measured resistivities to the applied displacements/strains. Electrical conductivity measurements revealed that the manufactured sensors are highly sensitive to small mechanical disturbances, especially for lower nanotube loadings when compared to traditional metallic or nanocomposite films. The present manufacturing method offers a new perspective for manufacturing highly sensitive 3D freestanding microstructured sensors. 相似文献
996.
Smith DM Dong B Marron RW Birnkrant MJ Elabd YA Natarajan LV Tondiglia VP Bunning TJ Li CY 《Nano letters》2012,12(1):310-314
Polymer electrolyte membranes (PEMs) with high and controlled ionic conductivity are important for energy-related applications, such as solid-state batteries and fuel cells. Herein we disclose a new strategy to fabricate long-range ordered PEMs with tunable ion conducting pathways using a holographic polymerization (HP) method. By incorporating polymer electrolyte into the carefully selected HP system, electrolyte layers/channels with length scales of a few tens of nanometers to micrometers can be formed with controlled orientation and anisotropy; ionic conductivity anisotropy as high as 37 has been achieved. 相似文献
997.
Subramani C Saha K Creran B Bajaj A Moyano DF Wang H Rotello VM 《Small (Weinheim an der Bergstrasse, Germany)》2012,8(8):1209-13, 1126
Biocompatible structures are produced for cellular patterning. The biocompatible surfaces are generated to provide protein nonfouling patterns, offering direct communication to the cells for controlling cell adhesion and proliferation. These biofunctional surfaces provide a platform for aligning the cells in the direction of patterns, indicating potential application in the field of tissue engineering. 相似文献
998.
Paola Palmero Mariangela Lombardi Laura Montanaro Mirella Azar Jerome Chevalier Vincent Garnier Gilbert Fantozzi 《International Journal of Applied Ceramic Technology》2009,6(3):420-430
Deagglomeration of a nanocrystalline transition alumina performed using different techniques was first demonstrated to be active in the achievement of a better powder compaction ability under uniaxial pressing and consequently in the development of a highly dense and homogeneous microstructure during pressureless sintering. A major effect, however, was associated to the heating rate chosen during the densification cycle. In fact, the influence of different heating rates (10°C/min or 1°C/min) on phase and microstructural evolution during sintering was investigated in depth on the above best green bodies. A low-rate thermal cycle leads to a significant reduction of the α-Al2 O3 crystallization temperature and promotes a more effective particle rearrangement during phase transformation. As a consequence, in the low-rate treated material, it was possible to avoid the development of a vermicular structure as usually expected during the densification of a transition alumina and to yield a more homogenously fired microstructure. 相似文献
999.
A. Veillère J.-M. Heintz N. Chandra J. Douin M. Lahaye G. Lalet C. Vincent J.-F. Silvain 《Materials Research Bulletin》2012,47(2):375-380
This study focuses on the fabrication, for power electronics applications, of adaptive heat sink material using copper alloys/carbon fibers (CF) composites. In order to obtain composite material with good thermal conductivity and a coefficient of thermal expansion close to the ceramic substrate, it is necessary to have a strong matrix/reinforcement bond. Since there is no reaction between copper and carbon, a carbide element (chromium or boron) is added to the copper matrix to create a strong chemical bond. Composite materials (Cu–B/CF and Cu–Cr/CF) have been produced by a powder metallurgy process followed by an annealing treatment in order to create the carbide at the interphase. Chemical (Electron Probe Micro-Analysis, Auger Electron Spectroscopy) and microstructural (Scanning and Transmission Electron Microscopies) techniques were used to study the location of the alloying element and the carbide formation before and after diffusion. Finally, the thermo-mechanical properties have been measured and a promising composite material with a coefficient of thermal expansion 25% lower than a classic copper/carbon heat sink has been obtained. 相似文献
1000.
The structural, electronic and magnetic properties of a 9-layer symmetrical FeMoO terminated (001)-oriented slab of double perovskite Sr2FeMoO6 have been studied by using the first-principle projector augmented wave potential within the generalized gradient approximation taking into account the on-site Coulomb repulsive (U = 2.0 eV for Fe and 1.0 eV for Mo). An outward relaxation is observed for each layer of the first four layers and the accompanying layer's rumpling has a decreasing trend from layer 1 to layer 4. Along Fe-O-Mo-O-Fe or Mo-O-Fe-O-Mo chain, the oxygen atom is closer to the adjacent Mo atom than to the adjacent Fe atom. The half-metallic nature ensures the symmetrical FeMoO terminated (001)-oriented slab of double perovskite Sr2FeMoO6 to be a potential application in spintronic devices. The Jahn-Teller structural distortions and the outward relaxations lead to the differences between pz state and similar px and py states, between dxy state and similar dyz and dxz states as well as between dz2 and dx2 − y2. The reduction in the restrictions from the reduction in the number of the near neighbors, especially the vanishing of the nearest neighbor oxygen atom just above the transition-metal (TM) atoms on the first layer makes not only the remaining axial TM-O distances slightly shorter than the four equatorial TM-O distances but also shifts toward higher energy region the occupied up-spin and down-spin states with respect to the cases of the TM atoms on the third and fifth layers. 相似文献