| 21. |
- An, Di, et al.
(författare)
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Additive manufacturing and characterization of complex Al2O3 parts based on a novel stereolithography method
- 2017
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Ingår i: International Journal of Applied Ceramic Technology. - : Wiley. - 1546-542X .- 1744-7402. ; 14:5, s. 836-844
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we prepared Al2O3 ceramic green parts with complex geometry and architecture using an additive manufacturing process based on stereolithography. The rheological and thermal behavior of Al2O3 slurry was firstly examined and used to establish the conditions for molding and debinding. As opposed to previous researches that only focused on manufacture techniques, the sintering behavior and densification process were systematically investigated. In addition, special attentions were paid to the evolution of microstructure between green bodies and sintered parts. The results showed that debound parts were equipped with uniform particle packing and narrow pore size distribution. The dimensions of the Al2O3 parts changed anisotropically with the different processing steps. The densification process was greatly accelerated by the decrease in pore size and annihilating of interconnected pores in which significant grain growth was observed above 1450 degrees C. The sintered part also had a homogeneous microstructure and no interface between adjacent layers. High densification (relative density of 99.1%) and much desirable Vickers hardness (17.9 GPa) of Al2O3 parts were achieved at the sintering temperature of 1650 degrees C.
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| 22. |
- Andersson, Anna, et al.
(författare)
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The landscape of somatic mutations in infant MLL-rearranged acute lymphoblastic leukemias.
- 2015
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 47:4, s. 192-330
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Tidskriftsartikel (refereegranskat)abstract
- Infant acute lymphoblastic leukemia (ALL) with MLL rearrangements (MLL-R) represents a distinct leukemia with a poor prognosis. To define its mutational landscape, we performed whole-genome, exome, RNA and targeted DNA sequencing on 65 infants (47 MLL-R and 18 non-MLL-R cases) and 20 older children (MLL-R cases) with leukemia. Our data show that infant MLL-R ALL has one of the lowest frequencies of somatic mutations of any sequenced cancer, with the predominant leukemic clone carrying a mean of 1.3 non-silent mutations. Despite this paucity of mutations, we detected activating mutations in kinase-PI3K-RAS signaling pathway components in 47% of cases. Surprisingly, these mutations were often subclonal and were frequently lost at relapse. In contrast to infant cases, MLL-R leukemia in older children had more somatic mutations (mean of 6.5 mutations/case versus 1.3 mutations/case, P = 7.15 × 10(-5)) and had frequent mutations (45%) in epigenetic regulators, a category of genes that, with the exception of MLL, was rarely mutated in infant MLL-R ALL.
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| 23. |
- Bu, Zhaojun, et al.
(författare)
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Performance of four mosses in a reciprocal transplant experiment : implications for peatland succession in NE China
- 2013
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Ingår i: Journal of Bryology. - 0373-6687 .- 1743-2820. ; 35, s. 220-227
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Tidskriftsartikel (refereegranskat)abstract
- Sphagnum dominates the moss layer in northern peatlands, but its dominance has decreased while there has been an expansion of other moss genera in some peatlands of NE China since the 1960s. To discover the mechanisms underlying this succession, we performed a four-month reciprocal transplant experiment in Hani Peatland with three Sphagnum species, Sphagnum palustre, S. magellanicum, and S. fuscum and one other moss Polytrichum strictum. Performance of the four mosses and the environmental factors: height above water table (HWT), vascular plant cover and pH, electrical conductivity, base cations, and N and P concentrations in water in the four moss habitats were measured. Biomass production in S. palustre was negatively affected by HWT. Phosphorus had a positive effect on biomass production in S. magellanicum and Polytrichum. None of the environmental factors had any effect on S. fuscum. Overall, the three Sphagnum species deteriorated in P. strictum hummocks, while P. strictum exhibited a wider ecological amplitude and maintained or increased its vigour levels in Sphagnum hummocks. Biomass production in S. palustre and S. magellanicum was negatively affected by P. strictum indicating the competitive ability of P. strictum. Our results suggest that its wide ecological amplitude and competitive ability may explain why P. strictum can expand and replace Sphagnum in some northern peatlands.
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| 24. |
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| 25. |
- Cao, Hui, et al.
(författare)
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Field Effects on the Statistical Behavior of the Molecular Conductance in a Single Molecular Junction in Aqueous Solution
- 2010
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Ingår i: NANO RES. - : Springer Science and Business Media LLC. - 1998-0124. ; 3:5, s. 350-355
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Tidskriftsartikel (refereegranskat)abstract
- We have combined molecular dynamics simulations with first-principles calculations to study electron transport in a single molecular junction of perylene tetracarboxylic diimide (PTCDI) in aqueous solution under external electric gate fields. It is found that the statistics of the molecular conductance are very sensitive to the strength of the electric field. The statistics of the molecular conductance are strongly associated with the thermal fluctuation of the water molecules around the PTCDI molecule. Our simulations reproduce the experimentally observed three orders of magnitude enhancement of the conductance, as well as the temperature dependent conductance, under the electrochemical gates. The effects of the molecular polarization and the dipole rearrangement of the aqueous solution are also discussed.
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| 26. |
- Cao, Hui, et al.
(författare)
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Identification of switching mechanism in molecular junctions by inelastic electron tunneling spectroscopy
- 2008
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 112:29, s. 11018-11022
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Tidskriftsartikel (refereegranskat)abstract
- We present first-principles studies on electron transport properties of Pd-dithiolated oligoaniline-Pd molecular junctions. It is to demonstrate the possibility of using inelastic electron tunneling spectroscopy (IETS) to identify the switching mechanism in the molecular junction. Calculations have successfully reproduced the experimentally observed conductance switching behavior and the corresponding inelastic electron tunneling spectra. It is shown that the conductance switching is induced by conformation changes of the intercalated dithiolated oligoaniline in the junctions rather than oxidation/reduction as proposed earlier. Among three possible isomers, the low and high conductance states are related to two symmetrical structures. The possible involvement of asymmetric structure is discussed. It is revealed that chemical bonds between the terminal S atom and Pd electrodes are quite weak with relatively long bond distances.
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| 27. |
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| 28. |
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| 29. |
- Cao, Hui, et al.
(författare)
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Temperature-dependent statistical behavior of single molecular conductance in aqueous solution
- 2008
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 130:21, s. 6674-
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Tidskriftsartikel (refereegranskat)abstract
- We have combined molecular dynamics simulations with first principles calculations to study electron 4 transport in a single molecule of perylene tetracarboxylic diimide (PTCDI) sandwiched between two gold electrodes with an aqueous electrolyte. This combination has for the first time allowed one to reveal statistical behavior of molecular conductance in solution at different temperatures and to produce conductance histograms that can be directly compared with experiments. Our calculations show that experimentally observed temperature-dependent conductance ran be attributed to the thermal effect on the hydrogen bonding network around the molecule and can be described by the radial distribution of water molecules surrounding the oxygen atom in the PTCDI molecule.
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| 30. |
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