| 1. |
- Lan, Ting, et al.
(författare)
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Extensive functional diversification of the Populus glutathione S-transferase supergene family
- 2009
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Ingår i: The Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 21:12, s. 3749-3766
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Tidskriftsartikel (refereegranskat)abstract
- Identifying how genes and their functions evolve after duplication is central to understanding gene family radiation. In this study, we systematically examined the functional diversification of the glutathione S-transferase (GST) gene family in Populus trichocarpa by integrating phylogeny, expression, substrate specificity, and enzyme kinetic data. GSTs are ubiquitous proteins in plants that play important roles in stress tolerance and detoxification metabolism. Genome annotation identified 81 GST genes in Populus that were divided into eight classes with distinct divergence in their evolutionary rate, gene structure, expression responses to abiotic stressors, and enzymatic properties of encoded proteins. In addition, when all the functional parameters were examined, clear divergence was observed within tandem clusters and between paralogous gene pairs, suggesting that subfunctionalization has taken place among duplicate genes. The two domains of GST proteins appear to have evolved under differential selective pressures. The C-terminal domain seems to have been subject to more relaxed functional constraints or divergent directional selection, which may have allowed rapid changes in substrate specificity, affinity, and activity, while maintaining the primary function of the enzyme. Our findings shed light on mechanisms that facilitate the retention of duplicate genes, which can result in a large gene family with a broad substrate spectrum and a wide range of reactivity toward different substrates.
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| 2. |
- Liu, Jing, et al.
(författare)
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Dielectric, piezoelectric, and ferroelectric properties of grain-orientated Bi3.25La0.75Ti3O12 ceramics
- 2007
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 102:10, s. 104107-
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Tidskriftsartikel (refereegranskat)abstract
- By dynamic forging during Spark Plasma Sintering (SPS), grain-orientated ferroelectric Bi3.25La0.75Ti3O12 (BLT) ceramics were prepared. Their ferroelectric, piezoelectric, and dielectric properties are anisotropic. The textured ceramics parallel and perpendicular to the shear flow directions have similar thermal depoling behaviors. The d(33) piezoelectric coefficient of BLT ceramics gradually reduces up to 350 degrees C; it then drops rapidly. The broadness of the dielectric constant and loss peaks and the existence of d(33) above the permittivity peak, T-m, show that the BLT ceramic has relaxor-like behavior.
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| 3. |
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| 4. |
- Tian, Haining, et al.
(författare)
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Tuning of phenoxazine chromophores for efficient organic dye-sensitized solar cells.
- 2009
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; :41, s. 6288-6290
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Tidskriftsartikel (refereegranskat)abstract
- Through introducing an energy antenna system into a simple phenoxazine dye (TH301), a novel and efficient dye TH305 was designed and synthesized for application in a dye sensitized solar cell with prominent overall conversion efficiency of 7.7%. [on SciFinder(R)]
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| 5. |
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| 6. |
- Yue, Cong, et al.
(författare)
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Numerical Investigation on the Effect of Filler Distribution on Effective Thermal Conductivity of Thermal Interface Material
- 2008
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Ingår i: 2008 International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2008; Pudong, Shanghai; China; 28 July 2008 through 31 July 2008. - 9781424427406 ; , s. C1-10
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Konferensbidrag (refereegranskat)abstract
- Thermal interface materials have been widely adopted in the thermal management for electronics system. Most of the thermal interface materials are made of polymers with thermally conductive particles distributed inside to enhance the thermal conductivity. Thus it is essential to figure out the effective thermal conductivity of this composite material. In the present paper, a parameterized cubic cell model had been developed and implemented by the finite element method. The numerical simulations were carried out to investigate the effect of the filler distributions on the effective thermal conductivity of the thermal interface materials. The volume percentage loadings of the particles ranging from 13% to 74% had been considered, and different particle distribution patterns had also been analyzed. The simulation results were compared with the experimental data as well as other models. A fairly good agreement was obtained for the particle volume percentage loading under consideration, which verified the developed cubic cell model.
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| 9. |
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| 10. |
- Zhang, Yan, 1976, et al.
(författare)
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Homogenization Model Based on Micropolar Theory for the Interconnection Layer in Microsystem Packaging
- 2006
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Ingår i: Proceedings of the eight IEEE CPMT International Symposium on High Density Packaging and Component Failure Anlaysis (HDP´06). - 1424404886 ; , s. 166-170
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Konferensbidrag (refereegranskat)abstract
- The increase in microsystem packaging density sets the requiement for component sizes in the system to become smaller and smaller. The scale decrease makes the analysis more complicated as the corresponding resolution should be improved to a great extent. Interconnection in the system is a typical interface structure that widely appear in the packaing system, in which periodic microstructures may be included inside. A homogenization model is developed in this paper, which focuses on the interface behavior. The interface model based on micropolar theory provides a natural way to include the characteristic scale that can reflect the size effect of the considered structure. Computations are carried out as the numerical example of the model, and comparisons of this model with those of the convertional method show its validity and efficiency.
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