| 1. |
- Wang, Yang, et al.
(författare)
-
Role of point defects on the reactivity of reconstructed anatase titanium dioxide (001) surface
- 2013
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 4, s. 2214-
-
Tidskriftsartikel (refereegranskat)abstract
- The chemical reactivity of different surfaces of titanium dioxide (TiO2) has been the subject of extensive studies in recent decades. The anatase TiO2(001) and its (1 x 4) reconstructed surfaces were theoretically considered to be the most reactive and have been heavily pursued by synthetic chemists. However, the lack of direct experimental verification or determination of the active sites on these surfaces has caused controversy and debate. Here we report a systematic study on an anatase TiO2(001)-(1 x 4) surface by means of microscopic and spectroscopic techniques in combination with first-principles calculations. Two types of intrinsic point defects are identified, among which only the Ti3+ defect site on the reduced surface demonstrates considerable chemical activity. The perfect surface itself can be fully oxidized, but shows no obvious activity. Our findings suggest that the reactivity of the anatase TiO2(001) surface should depend on its reduction status, similar to that of rutile TiO2 surfaces.
|
|
| 2. |
- Feng, Feng, et al.
(författare)
-
Room-temperature large magnetic-dielectric coupling in new phase anatase VTiO4
- 2013
-
Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 49:89, s. 10462-10464
-
Tidskriftsartikel (refereegranskat)abstract
- The synthetic new-phase VTiO4, as a new solid solution structure of anatase type, brings a large magnetodielectric ratio (Delta epsilon/epsilon(0)) of 7.2% at 300 K, representing a new simple-oxide structural catalogue exhibiting a room-temperature large magnetic-dielectric effect.
|
|
| 3. |
- Feng, Jun, et al.
(författare)
-
Giant Moisture Responsiveness of VS2 Ultrathin Nanosheets for Novel Touchless Positioning Interface
- 2012
-
Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 24:15, s. 1969-1974
-
Tidskriftsartikel (refereegranskat)abstract
- Utilizing a thin film of VS2 ultrathin nanosheets with giant and fast moisture responsiveness, a brand-new model of moisture-based positioning interface is put forward here, by which not only the 2D position information of finger tips can be acquired, but also the relative height can be detected as the third dimensionality, representing a promising platform for advanced man-machine interactive systems.
|
|
| 4. |
- Fu, Qiang, et al.
(författare)
-
Understanding the concept of randomness in inelastic electron tunneling excitations
- 2010
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 12:38, s. 12012-12023
-
Tidskriftsartikel (refereegranskat)abstract
- Inelastic electron tunneling excitation has been realized in the last decade as an effective way to probe reliably detailed atomic structures and control precisely behaviors of surface adsorbates at a single molecule level. A good understanding of rich and complex processes on the surface under inelastic electron excitations is of great importance, not only from a fundamental scientific point of view but also for potential practical applications. In this perspective paper, we give an overview of recent developments on excitations and characterizations of inelastic electron tunneling processes in surface adsorbates and molecular junctions. Special attention has been paid to the understanding of the randomness of the processes. A recently proposed general statistical model is introduced which has resolved a long-standing puzzle concerning the experimentally observed non-integer power law relationship between the rate of molecular conformation changes and the tunneling current. The success of the new model is highlighted by its applications for molecular switches.
|
|
| 5. |
- Jiang, Jun, et al.
(författare)
-
Structure dependent quantum confinement effect in hydrogen-terminated nanodiamond clusters
- 2010
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 108:9, s. 094303-
-
Tidskriftsartikel (refereegranskat)abstract
- Size-dependent quantum confinement effect on electronic structure of hydrogen-terminated carbon nanodiamond (ND) cluster has been investigated at the hybrid density functional theory level. Large scale all-electron calculations have been carried out for ND clusters of 0.76 nm (29 carbons) to 7.3 nm (20 959 carbons) in diameter. It is demonstrated that the quantum confinement effect in these clusters shows strong structural dependence. An important structural factor, describing the ratio between the number of atoms within the inner core and outer shell of the cluster, is identified which dictates the size-dependent behavior of the electronic states. For ND clusters with diameter smaller than 1.5 nm, the core-shell ratio changes fast with the increase in cluster size, and the evolution of electronic properties does not follow conventional quantum confinement models. For ND clusters exceeding the threshold of 1.5 nm in diameter, the change in the core-shell ratio saturates and quantum confinement effect becomes visible. Electronic states within the inner core and surface show different size dependence, but a general formula is proposed and describes their structure dependent quantum confinement effects. This formula provides useful insights into quantum confinement behavior in ND clusters, and thereby leads to important physical property information. The calculated electron effective masses for core and surface states of ND clusters are in very good agreement with the experiments.
|
|
| 6. |
- Li, Xiaofei, et al.
(författare)
-
Important structural factors controlling the conductance of DNA pairs in molecular junctions
- 2010
-
Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:33, s. 14240-14242
-
Tidskriftsartikel (refereegranskat)abstract
- It has been demonstrated experimentally that DNA base pairs and sequences can be identified by measuring their current changes in metal junctions. We report here a first principles study on electron transport properties of DNA base pairs in gold metal junctions. It is found that the experimentally observed electrode-separation-width-dependent current changes of DNA base pairs are not due to the difference in number of hydrogen bonds involved in different base pairs as proposed in earlier experimental studies but caused by the difference in their stacking structures. It reveals that such an electronic read-out technique is not exact, but practically useful since the statistically favorable misaligned junctions do show distinct dependence on the character of the base pair.
|
|
| 7. |
- Lin, Chenwen, et al.
(författare)
-
Hydrogen-Incorporated TiS2 Ultrathin Nanosheets with Ultrahigh Conductivity for Stamp-Transferrable Electrodes
- 2013
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 135:13, s. 5144-5151
-
Tidskriftsartikel (refereegranskat)abstract
- As a conceptually new class of two-dimensional (2D) materials, the ultrathin nanosheets as inorganic graphene analogues (IGAs) play an increasingly vital role in the new-generation electronics. However, the relatively low electrical conductivity of inorganic ultrathin nanosheets in current stage significantly hampered their conducting electrode applications in constructing nanodevices. We developed the unprecedentedly high electrical conductivity in inorganic ultrathin nanosheets. The hydric titanium disulfide (HTS) ultrathin nanosheets, as a new IGAs, exhibit the exclusively high electrical conductivity of 6.76 x 10(4) S/m at room temperature, which is superior to indium tin oxide (1.9 x 10(4) S/m), recording the best value in the solution assembled 2D thin films of both graphene (5.5 x 10(4) S/m) and inorganic graphene analogues (5.0 x 10(2) S/m). The modified hydrogen on S-Ti-S layers contributes additional electrons to the TiS2 layered frameworks, rendering the controllable electrical conductivity as well as the electron concentrations. Together with synergic advantages of the excellent mechanical flexibility, high stability, and stamp-transferrable properties, the HTS thin films show promising capability for being the next generation conducting electrode material in the nanodevice fields.
|
|
| 8. |
- Qiang, Fu, et al.
(författare)
-
A first principles study on the dissociation and rotation processes of a single O2 molecule on the Pt(111) surface
- 2011
-
Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society. - 1932-7447 .- 1932-7455. ; 115:14, s. 6864-6869
-
Tidskriftsartikel (refereegranskat)abstract
- Through density functional theory calculations, a detailed description on the dissociation and rotation processes of a single oxygen molecule adsorbed on the Pt(111) surface has been provided. Both dissociation and rotation reaction pathways have been identified, and some interesting phenomena related to the scanning tunneling microscopy experiments are finally explained. It is found that the prior occupation of oxygen atom on the metastable hcp-hollow site after O2 dissociation is originated from the particular structure of the intermediate state, and the low energy barrier of the O2 rotation can be attributed to an effective pathway. The experimentally observed noninteger power-law dependence of the rotation rate as a function of the current has been accurately determined by a newly developed statistical model for the inelastic electron tunneling. By considering the randomness of multielectron inelastic tunneling processes, it is found that the noninteger exponent comes from a statistical contribution of various n-electron events.
|
|
| 9. |
- Ren, Hao, et al.
(författare)
-
Identifying configuration and orientation of adsorbed molecules by inelastic electron tunneling spectra
- 2010
-
Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 133:6, s. 064702-
-
Tidskriftsartikel (refereegranskat)abstract
- Scanning tunneling microscopy (STM) topographical images and inelastic electron tunneling spectra (IETS) of a cis-2-butene molecule adsorbed on a Pd(110) surface have been simulated by first-principles calculations. Calculations have eliminated the ambiguity between the STM image and the adsorption orientation caused by the symmetry of the system and local chemical environment. A combination of STM images and IETS spectra has been shown to be particularly useful in determining the configuration of the molecule on the surface. (C) 2010 American Institute of Physics. [doi:10.1063/1.3474807]
|
|
| 10. |
- Sen, Partha, et al.
(författare)
-
Novel FOXF1 Mutations in Sporadic and Familial Cases of Alveolar Capillary Dysplasia with Misaligned Pulmonary Veins Imply a Role for its DNA Binding Domain
- 2013
-
Ingår i: Human Mutation. - : Hindawi Limited. - 1059-7794. ; 34:6, s. 801-811
-
Tidskriftsartikel (refereegranskat)abstract
- Alveolar capillary dysplasia with misalignment of pulmonary veins (ACD/MPV) is a rare and lethal developmental disorder of the lung defined by a constellation of characteristic histopathological features. Nonpulmonary anomalies involving organs of gastrointestinal, cardiovascular, and genitourinary systems have been identified in approximately 80% of patients with ACD/MPV. We have collected DNA and pathological samples from more than 90 infants with ACD/MPV and their family members. Since the publication of our initial report of four point mutations and 10 deletions, we have identified an additional 38 novel nonsynonymous mutations of FOXF1 (nine nonsense, seven frameshift, one inframe deletion, 20 missense, and one no stop). This report represents an up to date list of all known FOXF1 mutations to the best of our knowledge. Majority of the cases are sporadic. We report four familial cases of which three show maternal inheritance, consistent with paternal imprinting of the gene. Twenty five mutations (60%) are located within the putative DNA-binding domain, indicating its plausible role in FOXF1 function. Five mutations map to the second exon. We identified two additional genic and eight genomic deletions upstream to FOXF1. These results corroborate and extend our previous observations and further establish involvement of FOXF1 in ACD/MPV and lung organogenesis.
|
|
