SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Sundqvist Bertil) "

Sökning: WFRF:(Sundqvist Bertil)

  • Resultat 311-320 av 369
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
311.
  • Talyzin, Alexandr V., et al. (författare)
  • Pressure-induced insertion of liquid alcohols into graphite oxide structure
  • 2009
  • Ingår i: Journal of the American Chemical Society. - : ACS Publications. - 0002-7863 .- 1520-5126. ; 131:51, s. 18445-18449
  • Tidskriftsartikel (refereegranskat)abstract
    • Graphite oxide (GO) immersed in an excess of methanol and ethanol media is found to undergo a phase transformation at about 0.2−0.8 GPa, with an expansion of the unit cell volume by 40%, due to pressure-induced insertion of solvent into interlayer space. The pressure at which the structural expansion occurs does not correlate with the solidification pressure of the alcohol, in contrast to the graphite oxide/water system. The expanded high-pressure phase of GO/ethanol could be quenched back to ambient pressure. Compression of graphite oxide with a 2:1 water/methanol medium revealed a complex anomaly with two steps attributed to insertion of methanol and water at different pressure points.
  •  
312.
  • Talyzin, Alexandr V., et al. (författare)
  • Structural breathing of graphite oxide pressurized in basic and acidic solutions
  • 2011
  • Ingår i: The Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 2:4, s. 309-313
  • Tidskriftsartikel (refereegranskat)abstract
    • Graphite oxide immersed in excess of basic or acidic water media was studied using synchrotron X-ray diffraction at high pressure using diamond anvil cells. The lattice spacing of graphite oxide in excess of NaOH solution increases by the enormous value of 85% at 1.6 GPa. In contrast, structure expansion of graphite oxide immersed in liquid water with added HCl is significantly less pronounced compared with compression in pure water. The point of media solidification correlated with a sharp decrease in graphite oxide layers separation because of partial withdrawal of water from the structure. Therefore, pressure-induced structural breathing of graphite oxide due to insertion/desertion of water into/from interlayer space is strongly enhanced in basic media and suppressed in acidic media. The magnitude of structural breathing also depends on relative amounts of graphite oxide powder and solution. Strongly diluted samples with low relative amount of graphite oxide powder in the suspension exhibited less pronounced high-pressure anomaly.
  •  
313.
  • Ullakko, Kari, et al. (författare)
  • Isothermal Martensite Transformation of Fe-Ni-C Alloys as a Function of Hydrostatic Pressure
  • 1990
  • Ingår i: Materials Science Forum volumes 56-58. - Zürich : Trans Tech Publiations. ; , s. 197-200
  • Konferensbidrag (refereegranskat)abstract
    • Isothermal martensite transformation as a function of hydrostatic pressure was studied in Fe-Ni-C alloys. It was observed that the transformation was much the same as it happens as a function of time. Any noticeable differences in the morphology between isothermal and athermal martensite were not seen.
  •  
314.
  • Ulyanov, A.N., et al. (författare)
  • Crystal symmetry and pressure effects on the properties of mixed-valence manganites
  • 2003
  • Ingår i: Journal of Magnetism and Magnetic Materials vol. 258-259, Special Issue SI. - Amsterdam : Elsevier B.V.. ; , s. 312-314
  • Konferensbidrag (refereegranskat)abstract
    • A lattice structure effect on the magnetic and magnetotransport properties of La0.7Ca(0.3-x)SrxMnO3 lanthanum manganites have been studied. The Curie temperature pressure coefficient increased almost linearly under an applied pressure as dTc/dP=14K/GPa and as dTc/dP=7.5K/GPa in the orthorhombic and rhombohedral structures,respectively. This is caused by the different pressure effect on the Mn–O bond distances and on the Mn–O–Mn bond angles in those phases. The anomalous low value of dTc/dP(=3.5K/GPa) for La0.7Ca0.15Sr0.15MnO3 composition and a jump of the magnetoresistance maximum value at the concentrational Pbnm2R%3c phase transition were observed and discussed.
  •  
315.
  • Ulyanov, A.N., et al. (författare)
  • La0.7Ca0.3-xSrxMnO3 manganites: Effect of structure on the magnetic and transport properties.
  • 2002
  • Ingår i: Journal of the Physical Society of Japan. - : The Physical Society of Japan. - 0031-9015 .- 1347-4073. ; 71:3, s. 927-929
  • Tidskriftsartikel (refereegranskat)abstract
    • The effect of lattice structure on the magnetic and transport properties of La0.7Ca0.3-xSrxMnO3 (x= 0; 0.03; 0.06; ...; 0.3) lanthanum manganites have been studied. Curie temperature pressure coefficient, dTc/dP, showed the dependence on x value. Temperature Tc increased almost linearly under applied pressure as dTc/dP≈14 K/GPa and as dTc/dP≈7.5 K/GPa in the orthorhombic (Pbnm) and rhombohedral (R3c) phases, respectively. The value of dTc/dP(≈3.5 K/GPa) showed a minimum and a temperature of the resistance maximum, Tp(x), showed a change of slope at x=0.15, corresponding to the concentration structural phase transition. Differences between the values of dTc/dP and slopes of Tp versus x in Pbnm and R3c phases are explained by the different effect of external pressure on the Mn–O bond length and Mn–O–Mn bond angle, and by the different internal pressure effect in those phases, respectively
  •  
316.
  • Ulyanov, A. N., et al. (författare)
  • Structure and pressure effects on the properties of La0.7Ca0.3-xSrxMnO3 manganites.
  • 2002
  • Ingår i: Journal of Applied Physics vol. 91. - : American Institute of Physics. ; , s. 7739-7741
  • Konferensbidrag (refereegranskat)abstract
    • We report a study of the structure and pressure effects on magnetic and transport properties of a lanthanum manganite, La0.7Ca0.3–xSrxMnO3 (0<=x<=0.3, Deltax = 0.03). The pressure coefficient of the Curie temperature (Tc), dTc/dP, is shown to depend on x. The temperature Tc increases approximately linearly under applied pressure as dTc/dP[approximate]14 K/GPa in the orthorhombic (Pbnm) phase and as dTc/dP[approximate]7.5 K/GPa in the rhombohedral (R3-bar c). The value of dTc/dP shows a minimum ([approximate]3.5 K/GPa) and the temperature of the resistance maximum, Tp(x), shows a change of slope at x = 0.15, corresponding to a concentration structural phase transition. Differences between the values of dTc/dP and the slopes of Tp vs x in Pbnm and R3-bar c phases are explained by the different effect of external pressure on the Mn–O bond length and the Mn–O–Mn bond angle, and by the different internal pressure effect (depending on the value of x) in those phases, respectively.
  •  
317.
  • Vilaythong, Thongloon, 1960- (författare)
  • The role of practical work in physics education in Lao PDR
  • 2011
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The aim of this thesis is to get a better understanding of the role of practical work in physics education in the Lao People’s Democratic Republic (Lao PDR). The Lao PDR is one of least developed countries in the world with a weak base for science, and poor market opportunities for science graduates. The rapidly expanding educational system has many problems concerning quality of the infrastructure and staff competence. A combination of qualitative and quantitative methods was used in the study in order to assure reliability of the results. Data was collected through questionnaires, interviews, video-recordings, and my own ethnographic experiences of working in the Lao educational system for more than thirty years. The study was informed and results analysed with help of curriculum perspective and Cultural-Historical Activity Theory (CHAT). The findings show that Lao physics education curriculum at all levels is dominated by very traditional forms of teaching with an almost total absence of practical. Official curricular documents have statements prescribing teachers to do practical work in high school and university courses. However, few institutions have functioning equipment and skilled teachers for organising practical activities. Therefore, the majority of Lao students come to university and even can finish university without experience of practical work in physics. This shows the gap that exists between intended and implemented curricula. The majority of the students understand the importance of having practical activities in physics. However, after being exposed to laboratory experiments in an introductory physics course, they expressed criticism about the quality of instruction and the process of the practical work organisation. The laboratory group work analysis showed that discussions were mainly focused on understanding the experimental procedures, manipulating equipment, and collecting data for the report rather than on the physics content (object of activity, in CHAT terms). Based on the research results, it is possible to suggest that a systemic approach is needed to stimulate the development of a new practical work culture in schools and universities. This approach should include training and incentives for science teachers, development of assessment strategies including practical work, maintenance structures for physics equipment, and technical support for the organisation of demonstrations and laboratory exercises.
  •  
318.
  • Wang, Lin, et al. (författare)
  • High-pressure studies of Nano/sub-micrometer C70 rods
  • 2005
  • Ingår i: High Energy Physics and Nuclear Physics B. - 0254-3052. ; 29:Supplement, s. 112-115
  • Tidskriftsartikel (refereegranskat)abstract
    • We have successfully synthesized C-70 rods in nano/sub-micrometers scale by evaporating solvent method. The diameter of the as grown C-70 rods is similar to 500 nm, and the length is similar to 10 mu m. The EDXD pattern and Raman spectroscopy for as -grown sample indicate that the as grown C-70 rod is in hcp structure. The pressure-induced structural phase transition has been studied by using DAC combined with EDXD and Raman spectroscopy methods under quasi-hydrostatic pressure up to 26.1GPa. It is found that hcp structure transforms into amorphous phase for C-70 rods in the pressure range from 23.3 to 26.1GPa, which is higher than the transformation pressure for bulk C-70 crystals. The phase transition is irreversible and it is induced by the collapse of C-70 cage.
  •  
319.
  • Wang, Lin, et al. (författare)
  • Highly Enhanced Luminescence from Single-Crystalline C60·1m-xylene Nanorods
  • 2006
  • Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 18:17, s. 4190-4194
  • Tidskriftsartikel (refereegranskat)abstract
    • Single-crystalline C60â1m-xylene nanorods with a hexagonal structure were successfully synthesizedby evaporating a C60 solution in m-xylene at room temperature. The ratio of the length to the diameterof the nanorods can be controlled in the range of 10 to over 1000 for different applications. Thephotoluminescence (PL) intensity of the nanorods is about 2 orders of magnitude higher than that forpristine C60 crystals in air. Both UV and Raman results indicate that there is no charge transfer betweenC60 and m-xylene. It was found that the interaction between C60 and m-xylene molecules is of the vander Waals type. This interaction reduces the icosahedral symmetry of C60 molecule and induces strongPL from the solvate nanorods.
  •  
320.
  • Wang, Lin, et al. (författare)
  • Synthesis and high pressure induced amorphization of C60 nanosheets
  • 2007
  • Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 91:10, s. 103112-
  • Tidskriftsartikel (refereegranskat)abstract
    • C-60 nanosheets with thicknesses in the nanometer range were synthesized by a simple method. Compared to bulk C-60, the lattice of the nanosheets is expanded by about 0.4%. In situ Raman spectroscopy and energy-dispersive x-ray diffraction under high pressures have been employed to study the structure of the nanosheets. The studies indicate that the bulk modulus of the C-60 nanosheets is significantly larger than that of bulk C-60. The C-60 cages in nanosheets can persist at pressures over 30 GPa, 3 GPa higher than for bulk C-60. These results suggest that C-60 crystals in even small size will be a potential candidate of superhard materials.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 311-320 av 369
Typ av publikation
tidskriftsartikel (222)
konferensbidrag (128)
forskningsöversikt (7)
doktorsavhandling (5)
bokkapitel (4)
annan publikation (2)
visa fler...
proceedings (redaktörskap) (1)
visa färre...
Typ av innehåll
refereegranskat (338)
övrigt vetenskapligt/konstnärligt (27)
populärvet., debatt m.m. (4)
Författare/redaktör
Sundqvist, Bertil (357)
Liu, Bingbing (60)
Yao, Mingguang (55)
Wågberg, Thomas (52)
Soldatov, Alexander (38)
Andersson, Ove (30)
visa fler...
Cui, Tian (30)
Zou, Guangtian (27)
Wang, Lin (24)
Jacobsson, Per (20)
McRae, Edward (18)
Esel'son, V.B. (17)
Dolbin, Alexander V. (16)
Gavrilko, V.G. (15)
Zou, Bo (15)
Liu, Dedi (15)
Andersson, Britt M. (14)
Li, Quanjun (14)
Hou, Yuanyuan (14)
Lelaurain, Michelle (13)
Lundin, Anders (13)
Liu, Ran (13)
Iwasiewicz-Wabnig, A ... (13)
Yu, Shidan (13)
Talyzin, Alexandr (12)
Bäckström, Gunnar (12)
Makarova, Tatiana L. (12)
Manzhelii, V. G. (11)
Andersson, Odd E. (11)
Cui, Wen (11)
Launois, Pascale (11)
Moret, Roger (11)
Gadd, G.E. (10)
Moricca, S. (10)
Marêché, Jean-Franco ... (10)
Fransson, Åke (10)
Nyeanchi, Emmanuel B ... (10)
Vinnikov, N A (10)
Cassidy, D. (9)
Blank, Vladimir D. (9)
Johnels, Dan (9)
Dong, Jiajun (9)
Zhu, Xiaomei (8)
Talyzin, Alexandr V. (7)
Liu, Bo (7)
Rapp, Östen (7)
Buga, Sergei G. (7)
Dubitsky, Gennadii A ... (7)
Serebryanaya, Nadejd ... (7)
Zou, Yonggang (7)
visa färre...
Lärosäte
Umeå universitet (356)
Luleå tekniska universitet (31)
Göteborgs universitet (3)
Jönköping University (3)
Uppsala universitet (2)
Lunds universitet (2)
visa fler...
Chalmers tekniska högskola (2)
Kungliga Tekniska Högskolan (1)
Stockholms universitet (1)
Linköpings universitet (1)
Karolinska Institutet (1)
visa färre...
Språk
Engelska (367)
Svenska (2)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (346)
Teknik (17)
Medicin och hälsovetenskap (7)
Samhällsvetenskap (2)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy