| 1. |
- Ablikim, M., et al.
(författare)
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Measurements of (XcJ)-> K+K-K+K- decays
- 2006
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 642:3, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- Using 14M psi(2S) events taken with the BESII detector, chi(cJ) -> 2(K+K-) decays are studied. For the four-kaon final state, the branching fractions are B(chi(c0,1,2) ->.2(K+K-)) = (3.48 +/- 0.23 +/- 0.47) x 10(-3), (0.70 +/- 0.13 +/- 0.10) x 10(-3), and (2.17 +/- 0.20 +/- 0.31) x 10(-3). For the phi K+K- final state, the branching fractions, which are measured for the first time, are B(chi(c0,1,2) -> phi K+K-) = (1.03 +/- 0.22 +/- 0.15) x 10(-3), (0.46 +/- 0.16 +/- 0.06) x 10(-3), and (1.67 +/- 0.26 +/- 0.24) x 10(-4). For the phi phi final state, B(chi(c0,2) -> phi phi) = (0.94 +/- 0.21 +/- 0.13) x 10(-3) and (1.70 +/- 0.30 +/- 0.25) x 10(-3).
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| 2. |
- Adare, A., et al.
(författare)
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Photon-hadron jet correlations in p plus p and Au plus Au collisions at s(NN)=200 GeV
- 2009
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:2
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Tidskriftsartikel (refereegranskat)abstract
- We report the observation at the Relativistic Heavy Ion Collider of suppression of back-to-back correlations in the direct photon+jet channel in Au+Au relative to p+p collisions. Two-particle correlations of direct photon triggers with associated hadrons are obtained by statistical subtraction of the decay photon-hadron (gamma-h) background. The initial momentum of the away-side parton is tightly constrained, because the parton-photon pair exactly balance in momentum at leading order in perturbative quantum chromodynamics, making such correlations a powerful probe of the in-medium parton energy loss. The away-side nuclear suppression factor, I-AA, in central Au+Au collisions, is 0.32 +/- 0.12(stat)+/- 0.09(syst) for hadrons of 3 < p(T)(h)< 5 in coincidence with photons of 5 < p(T)(gamma)< 15 GeV/c. The suppression is comparable to that observed for high-p(T) single hadrons and dihadrons. The direct photon associated yields in p+p collisions scale approximately with the momentum balance, z(T)equivalent to p(T)(h)/p(T)(gamma), as expected for a measurement of the away-side parton fragmentation function. We compare to Au+Au collisions for which the momentum balance dependence of the nuclear modification should be sensitive to the path-length dependence of parton energy loss.
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| 3. |
- Adare, A., et al.
(författare)
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Measurement of Bottom Versus Charm as a Function of Transverse Momentum with Electron-Hadron Correlations in p plus p Collisions at s=200 GeV
- 2009
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Ingår i: Physical Review Letters. - 1079-7114. ; 103:8
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Tidskriftsartikel (refereegranskat)abstract
- The momentum distribution of electrons from semileptonic decays of charm and bottom quarks for midrapidity |y|< 0.35 in p+p collisions at s=200 GeV is measured by the PHENIX experiment at the Relativistic Heavy Ion Collider over the transverse momentum range 2 < p(T)< 7 GeV/c. The ratio of the yield of electrons from bottom to that from charm is presented. The ratio is determined using partial D/D -> e(+/-)K(-/+)X (K unidentified) reconstruction. It is found that the yield of electrons from bottom becomes significant above 4 GeV/c in p(T). A fixed-order-plus-next-to-leading-log perturbative quantum chromodynamics calculation agrees with the data within the theoretical and experimental uncertainties. The extracted total bottom production cross section at this energy is sigma(bb)=3.2(-1.1)(+1.2)(stat)(-1.3)(+1.4)(syst)mu b.
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| 4. |
- Adare, A., et al.
(författare)
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Onset of pi(0) Suppression Studied in Cu plus Cu Collisions at root s(NN)=22.4, 62.4, and 200 GeV
- 2008
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Ingår i: Physical Review Letters. - 1079-7114. ; 101:16
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Tidskriftsartikel (refereegranskat)abstract
- Neutral pion transverse momentum (p(T)) spectra at midrapidity (|y| less than or similar to 0.35) were measured in Cu + Cu collisions at root s(NN) = 22.4, 62.4, and 200 GeV. Relative to pi(0) yields in p + p collisions scaled by the number of inelastic nucleon-nucleon collisions (N-coll) the pi(0) yields for p(T) greater than or similar to 2 GeV/c in central Cu + Cu collisions are suppressed at 62.4 and 200 GeV whereas an enhancement is observed at 22.4 GeV. A comparison with a jet-quenching model suggests that final state parton energy loss dominates in central Cu + Cu collisions at 62.4 and 200 GeV, while the enhancement at 22.4 GeV is consistent with nuclear modifications in the initial state alone.
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| 5. |
- Adare, A., et al.
(författare)
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Gluon-Spin Contribution to the Proton Spin from the Double-Helicity Asymmetry in Inclusive pi(0) Production in Polarized p plus p Collisions at root s=200 GeV
- 2009
-
Ingår i: Physical Review Letters. - 1079-7114. ; 103:1
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Tidskriftsartikel (refereegranskat)abstract
- The double helicity asymmetry in neutral pion production for p(T) = 1 to 12 GeV/c was measured with the PHENIX experiment to access the gluon-spin contribution, Delta G, to the proton spin. Measured asymmetries are consistent with zero, and at a theory scale of mu 2 = 4 GeV2 a next to leading order QCD analysis gives Delta G([0.02,0.3]) = 0.2, with a constraint of -0.7 < Delta G([0.02,0.3]) < 0.5 at Delta chi(2) = 9 (similar to 3 sigma) for the sampled gluon momentum fraction (x) range, 0.02 to 0.3. The results are obtained using predictions for the measured asymmetries generated from four representative fits to polarized deep inelastic scattering data. We also consider the dependence of the Delta G constraint on the choice of the theoretical scale, a dominant uncertainty in these predictions.
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| 6. |
- Adare, A., et al.
(författare)
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Inclusive cross section and double helicity asymmetry for pi(0) production in p plus p collisions at root s=62.4 GeV
- 2009
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Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 79:1
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Tidskriftsartikel (refereegranskat)abstract
- The PHENIX experiment presents results from the RHIC 2006 run with polarized p + p collisions at root s = 62.4 GeV, for inclusive pi(0) production at midrapidity. Unpolarized cross section results are measured for transverse momenta p(T) = 0.5 to 7 GeV/c. Next-to-leading order perturbative quantum chromodynamics calculations are compared with the data, and while the calculations are consistent with the measurements, next-to-leading logarithmic corrections improve the agreement. Double helicity asymmetries A(LL) are presented for p(T) = 1 to 4 GeV/c and probe the higher range of Bjorken x of the gluon (x(g)) with better statistical precision than our previous measurements at root s = 200 GeV. These measurements are sensitive to the gluon polarization in the proton for 0.06 < x(g) < 0.4.
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| 7. |
- Carninci, P, et al.
(författare)
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The transcriptional landscape of the mammalian genome
- 2005
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 309:5740, s. 1559-1563
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Tidskriftsartikel (refereegranskat)abstract
- This study describes comprehensive polling of transcription start and termination sites and analysis of previously unidentified full-length complementary DNAs derived from the mouse genome. We identify the 5′ and 3′ boundaries of 181,047 transcripts with extensive variation in transcripts arising from alternative promoter usage, splicing, and polyadenylation. There are 16,247 new mouse protein-coding transcripts, including 5154 encoding previously unidentified proteins. Genomic mapping of the transcriptome reveals transcriptional forests, with overlapping transcription on both strands, separated by deserts in which few transcripts are observed. The data provide a comprehensive platform for the comparative analysis of mammalian transcriptional regulation in differentiation and development.
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| 8. |
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| 9. |
- Han, Y., et al.
(författare)
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X-Radiation Induces Non-Small-Cell Lung Cancer Apoptosis by Upregulation of Axin Expression
- 2009
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Ingår i: International Journal of Radiation Oncology Biology Physics. - : Elsevier BV. - 0360-3016. ; 75:2, s. 518-526
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Axis inhibition (Axin) is an important negative regulator of the Wnt pathway. This study investigated the relationship between Axin expression and sensitivity to X-rays in non-small-cell lung cancer (NSCLC) to find a useful indicator of radiosensitivity. Methods and Materials: Tissue from NSCLC patients, A549 cells, and BE1 cells expressing Axin were exposed to 1-Gy of X-radiation. Axin and p53 expression levels were detected by immunohistochemistry and reverse transcription-PCR. Apoptosis was determined by TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) assay and FACS (fluorescence-activate cell sorter) analysis. Caspase-3 activity was determined by Western blotting. Phospho-JNK expression was determined by immunofluorescence. Results: The expression of Axin was significantly lower in NSCLC tissues than in normal lung tissues (p less than 0.05). Axin expression correlates with differentiation, TNM staging, and lymph node metastasis of NSCLC (p less than 0.05). Its expression negatively correlates with the expression of p53(mt) (p=0.000) and positively correlates with apoptosis (p=0.002). The prognosis of patients with high expression of Axin was better than those with low expression. X-radiation increases Axin expression in NSCLC tissue, and caspase-3 is significantly higher in samples in which Axin is increased (p less than 0.05). Both X-radiation and Axin induce apoptosis of A549 and BE1 cells; however, the combination of the two enhances the apoptotic effect (p less than 0.05). In A549 cells, inhibition of p53 blocks Axin-induced apoptosis, whereas in BE1 cells, the JNK pathway is required. Conclusions: Axin induces the p53 apoptotic pathway in cells where this pathway is intact; however, in cells expressing p53(mt), Axin induces apoptosis via the JNK pathway. Elevated Axin expression following X-ray exposure is a reliable indicator for determining the radiosensitivity of NSCLC.
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| 10. |
- Zhang, Fengling, et al.
(författare)
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Ordered mesoporous Ag-TiO2-KIT-6 heterostructure: synthesis, characterization and photocatalysis
- 2009
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 1364-5501 .- 0959-9428. ; 19:18, s. 2771-2777
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Tidskriftsartikel (refereegranskat)abstract
- Ordered mesoporous Ag-TiO2-KIT-6 heterostructured nanocrystals were successfully synthesized by a template-based method, where a layer of TiO2 and Ag2O nanoparticles were deposited on cubic (Ia3d) silica (KIT-6) in an orderly manner; at the same time, the formed Ag2O nanoparticles were photolyzed to metallic Ag nanoparticles. Our results show that Ag-TiO2-KIT-6 is an ordered mesoporous composite material, which is composed of Ag-TiO2 heterostructures and the amorphous KIT-6 template. In addition, Ag-TiO2-KIT-6 possesses the highest photocatalytic activity among the as-synthesized photocatalysts, which can be attributed to the Ag-TiO2 heterojunctions and the excellent texture: (1) Ag-TiO2 heterojunctions improve the separation of photogenerated electron-hole pairs due to the potential energy differences between Ag and TiO2 nanocrystals, thus enhancing the photocatalytic activity; (2) the Ag-TiO2-KIT-6 sample possesses a high BET surface area and a large number of ordered pore channels, which facilitate adsorption and transportation of dye molecules, also leading to higher photocatalytic activity. It was also found that the Ag-TiO2 heterostructure plays a more important role in enhancing the photocatalytic activity than high BET surface area.
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| 11. |
- Wang, Wei-Zhou, et al.
(författare)
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Comparative analysis of gene expression profiles between the normal human cartilage and the one with endemic osteoarthritis.
- 2009
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Ingår i: Osteoarthritis and Cartilage. - : Saunders Elsevier. - 1063-4584 .- 1522-9653. ; 17:1, s. 83-90
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate the differences in gene expression profiles of adult articular cartilage with endemic osteoarthritis (OA), Kashin-Beck disease (KBD), and the same regions in the normal joint.METHODS: The messenger RNA expression profiles of articular cartilage with KBD diagnosed according to "Diagnosing Criteria of Kashin-Beck Disease in China" were compared with the normal cartilage. Total RNA isolated separately from four pairs of the KBD and normal cartilage samples were evaluated by oligonucleotide microarray analysis. The microarray data were confirmed by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) amplification and were compared with previously published experiments.RESULTS: About 4100 transcripts, which corresponded to 35% of the expressed transcripts, showed >or=twofold differences in expression between the cartilage tissues in pairs. Approximately 2% of the expressed genes (79, 55 genes expressed in KBD>normal; 24 genes expressed in KBDCONCLUSION: Differences between KBD cartilage and the normal exhibited a similar pattern among the four pairs examined, indicating the presence of common mechanisms mainly including chondrocyte metabolism and apoptosis that contribute to cartilage destruction in KBD.
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| 12. |
- Zheng, L. R., et al.
(författare)
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Network Structured SnO2/ZnO Heterojunction Nanocatalyst with High Photocatalytic Activity
- 2009
-
Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 48:5, s. 1819-1825
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Tidskriftsartikel (refereegranskat)abstract
- A network-structured SnO2/ZnO heterojunction nanocatalyst with high photocatalytic activity was successfully synthesized through a simple two-step solvothermal method. The as-synthesized samples are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy, N-2 physical adsorption, and UV-vis spectroscopy. The results show that the SnO2/ZnO sample with a molar ratio of Sn/Zn = 1 is a mesoporous composite material composed of SnO2 and ZnO. The photocatalytic activity of SnO2/ZnO heterojunction nanocatalysts for the degradation of methyl orange is much higher than those of solvothermally synthesized SnO2 and ZnO samples, which can be attributed to the SnO2-ZnO heterojunction, the pore structure, and higher Brunauer-Emmeff-Teller (BET) surface area of the sample: (1) The SnO2-ZnO heterojunction improves the separation of photogenerated electron-hole pairs due to the potential energy differences between SnO2 and ZnO, thus enhancing the photocatalytic activity. (2) The SnO2/ZnO sample might possess more surface reaction sites and adsorb and transport more dye molecules due to the higher BET surface area and many pore channels, also leading to higher photocatalytic activity.
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| 13. |
- Zheng, Y. H., et al.
(författare)
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Photocatalytic activity of Ag/ZnO heterostructure nanocatalyst: Correlation between structure and property
- 2008
-
Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 112:29, s. 10773-10777
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Tidskriftsartikel (refereegranskat)abstract
- Ag/ZnO heterostructure nanocatalysts with Ag content of 1 wt % are successfully prepared through three different simple methods, where chemical reduction and photolysis reaction are adopted to fabricate the heterostructure. The dispersity of Ag clusters and/or nanoparticles in Ag/ZnO nanocatalyst is investigated by EDX mapping and XPS techniques. The experimental results show that deposition-precipitation is an efficient method to synthesize Ag/ZnO nanocatalyst with highly dispersed Ag clusters and/or nanoparticles; the photocatalytic activity of Ag/ZnO photocatalysts mainly depends on the dispersity of metallic Ag in Ag/ZnO nanocatalyst; the higher the dispersity of metallic Ag in Ag/ZnO nanocatalyst is, the higher the photocatalytic activity of Ag/ZnO photocatalyst should be. In addition, it is also found that the dispersity of Ag/ZnO photocatalyst in the dye solution is another key factor for liquid-phase photocatalysis due to the UV-light utilizing efficiency. The higher the UV-light utilizing efficiency is, the higher the photocatalytic activity of Ag/ZnO heterostructure photocatalyst should be.
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| 14. |
- Wei, S., et al.
(författare)
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Historical trends of organic pollutants in sediment cores from Hong Kong
- 2008
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Ingår i: Marine Pollution Bulletin. - : Elsevier. - 0025-326X .- 1879-3363. ; 57:6-12, s. 758-766
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies have indicated the occurrence of a wide range of trace organic contaminants, including polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the Hong Kong environment. These contaminants are potentially harmful to ecological systems, particularly in coastal areas. In this study, two sediment cores (4 m) were collected from southern waters of Hong Kong in 2004 to study the historical trends, distribution patterns, and potential sources of trace organic contaminants. DDTs (p,p′-DDT, o,p′-DDT, p,p′-DDD, o,p′-DDD and p,p′-DDE), hexachlorohexanes (HCHs) (α and γ), hexachlorobenzene (HCB), and PCBs were detected in the samples, whereas other target compounds were all below detection limits. Many OCPs have not been produced or used for many years due to toxicological or environmental concerns and PCB use is prohibited in Hong Kong. However, some compounds were still detectable in recent years, and were found to be widely distributed in the environment, likely because of pollutant inputs from the highly industrialized Pearl River Delta region. These results provide important information on current and historical contamination in Hong Kong, and help to reconstruct the pollution history of these trace organic pollutants in Hong Kong coastal waters.
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| 15. |
- Darakchieva, Vanya, et al.
(författare)
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Electron accumulation at nonpolar and semipolar surfaces of wurtzite InN from generalized infrared ellipsometry
- 2009
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Ingår i: APPLIED PHYSICS LETTERS. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 95:20, s. 202103-
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Tidskriftsartikel (refereegranskat)abstract
- The free electron properties of nonpolar (1120)-oriented and semipolar (1011)-oriented wurtzite InN films are studied by generalized infrared ellipsometry (GIRSE). We demonstrate the sensitivity of GIRSE to the surface charge accumulation layer and find a distinct surface electron accumulation to occur at all surfaces. The obtained surface electron sheet densities are found to vary from 0.9x10(13) to 2.3x10(14) cm(-2) depending on the surface orientation and bulk electron concentration. The upper limits of the surface electron mobility parameters of 417-644 cm(2)/V s are determined and discussed in the light of electron confinement at the surface.
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| 16. |
- Hsu, Li-Han, 1981, et al.
(författare)
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Fabrication process and 110 GHz measurement result of MS-to-CPW RF-via transition for RF-MEMS devices packaging applications
- 2009
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Ingår i: 2009 International Conference on Compound Semiconductor Manufacturing Technology, CS MANTECH 2009. - 9781893580138
-
Konferensbidrag (refereegranskat)abstract
- This paper presents the fabrication process of RF-via (0-level) and flip-chip bump (1-level) transitions for applications of packaging MS (microstrip) RF-MEMS devices. The interconnect structure with MS-to-CPW transition between GaAs MEMS substrate and Al2O3 motherboard was in-house fabricated. A novel fabrication process for RF-MEMS packaging is in detail. After fabrication, the samples were measured up to 110 GHz using on-wafer probing measurement. From the measured results, the insertion loss of entire interconnect structure is better than -2 dB up to 100 GHz, documenting the feasibility for millimeter-wave RF-MEMS devices packaging applications.
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| 17. |
- Wei, H. Y., et al.
(författare)
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Cold ionospheric plasma in Titan's magnetotail
- 2007
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 34:24, s. L24S06-
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between Titan and the corotating Saturnian plasma forms an induced magnetosphere with an elongated Alfven-wing-style magnetotail. On 26 December 2005, the Cassini spacecraft flew through Titan's magnetotail, providing the first distant tail observation, over 5 Titan radii downstream. We examine measurements observed by the magnetometer and Langmuir probe during this pass. We use the direction of the magnetic field along the trajectory to identify the source regions of plasma reaching the spacecraft. Cold plasma, with a density of about 10 cm(-3), is found magnetically connected to the ionosphere. Titan's ionosphere appears to be escaping along field lines down the tail, leading to particle loss from the atmosphere.
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| 18. |
- Wei, P K, et al.
(författare)
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Beaming effect of optical near-field in multiple metallic slits with nanometric linewidth and micrometer pitch
- 2005
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Ingår i: Optics Communications. - : Elsevier BV. - 0030-4018. ; 253:1-3, s. 198-204
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Tidskriftsartikel (refereegranskat)abstract
- The beaming effect and interference patterns on the exit surface of multiple nano metallic slits with micrometer pitch were observed by scanning near-field optical microscopy. The near-field light intensity for multiple slits had a longer propagation tail and a smaller diverging angle as compared to that in a single slit. From finite-difference time-domain calculations, we verify that these fringe patterns come from the interference effect of longitudinal electric field, which is propagating along the surface. The beaming light in the slit openings is also attributed to the addition of longitudinal fields.
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| 19. |
- Xiong, Wei, et al.
(författare)
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Thermodynamic investigation of the galvanizing systems, I : Refinement of the thermodynamic description for the Fe-Zn system
- 2009
-
Ingår i: Calphad. - : Elsevier BV. - 0364-5916 .- 1873-2984. ; 33:2, s. 433-440
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Tidskriftsartikel (refereegranskat)abstract
- The thermodynamic description for the Fe-Zn system was updated using CALPHAD approach. A set of self-consistent thermodynamic model parameters for this system was obtained by considering the available experimental data. Compared with the previous thermodynamic modeling, the present assessment with fewer parameters shows not only a better agreement with the experiments but also sounder physical meaning. The present CALPHAD modeling coupled with the ab initio calculations were used to predict the enthalpies of formation of the solid phases in the Fe-Zn system.
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| 20. |
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| 21. |
- Chen, D., et al.
(författare)
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Dual-wavelength single-longitudinal-mode erbium-doped fibre laser based on fibre Bragg grating pair and its application in microwave signal generation
- 2008
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 44:7, s. 459-460
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Tidskriftsartikel (refereegranskat)abstract
- A simple dual-wavelength single-longitudinal-mode erbium-doped fibre laser is proposed by incorporating a fibre Bragg grating pair, which is used as a Fabry-Perot filter with two ultra-narrow (similar to 0.12 pm) transmission bands. Stable dual-wavelength single-longitudinal-mode lasing with a wavelength spacing of similar to 0.08 nm is achieved at room temperature. By beating the dual-wavelengths at a photodetector, a microwave signal at 9.616 GHz is demonstrated with a frequency stability better than 1 MHz and a spectral width less that 10 kHz.
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| 22. |
- Chen, P.Y., et al.
(författare)
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Synthesis design of artificial magnetic metamaterials using a genetic algorithm
- 2008
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Ingår i: Optics Express. - 1094-4087. ; 16:17, s. 12806-12818
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we present a genetic algorithm (GA) as one branch of artificial intelligence (AI) for the optimization-design of the artificial magnetic metamaterial whose structure is automatically generated by computer through the filling element methodology. A representative design example, metamaterials with permeability of negative unity, is investigated and the optimized structures found by the GA are presented. It is also demonstrated that our approach is effective for the synthesis of functional magnetic and electric metamaterials with optimal structures. This GA-based optimization-design technique shows great versatility and applicability in the design of functional metamaterials. © 2008 Optical Society of America.
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| 23. |
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| 24. |
- Cheng, M.H., et al.
(författare)
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Growth and characterization of Ge nanostructures selectively grown on patterned Si
- 2008
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Ingår i: Thin Solid Films. - : Elsevier Science B.V., Amsterdam.. - 0040-6090 .- 1879-2731. ; 517:1, s. 57-61
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Tidskriftsartikel (refereegranskat)abstract
- By utilizing different distribution of strain fields around the edges of oxide, which are dominated by a series of sizes of oxide-patterned windows, long-range ordered self-assembly Ge nanostructures, such as nano-rings, nano-disks and nano-dots, were selectively grown by ultra high vacuum chemical vapor deposition (UHV-CVD) on Si (001) substrates. High-resolution double-crystal symmetrical omega/2 theta scans and two-dimensional reciprocal space mapping (2D-RSM) technologies employing the triple axis X-ray diffractometry have been used to evaluate the quality and strain status of as-deposited as well as in-situ annealed Ge nanostructures. Furthermore, we also compare the quality and strain status of Ge epilayers grown on planar unpatterned Si substrates. It was found that the quality of all Ge epitaxial structures is improved after in-situ annealing process and the quality of Ge nano-disk structures is better than that of Ge epilayers; on planar unpatterned Si substrates, because oxide sidewalls are effective dislocation sinks. We also noted that the degree of relaxation for as-deposited Ge epilayers on planar unpatterned Si substrates is less than that for as-deposited Ge nano-disk structures. After in-situ annealing process,all Ge epitaxial structures are almost at full relaxation whatever Ge epitaxial structures grew on patterned or unpatterned Si substrates.
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| 25. |
- Ding, Wen-hong, et al.
(författare)
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Echocardiographic predictors of left ventricular functional recovery following valve replacement surgery for severe aortic stenosis.
- 2008
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Ingår i: International Journal of Cardiology. - : Elsevier BV. - 0167-5273 .- 1874-1754. ; 128:2, s. 178-84
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: We aimed to identify the most sensitive echocardiographic measurements that predict recovery of left ventricular function following valve replacement surgery in patients with severe aortic stenosis (AS) and LV dysfunction.METHODS: We studied 66 patients (mean age 70+/-2 years, 53 male) who underwent AVR for severe AS with concurrent LV dysfunction between 1998 and 2003 at the Royal Brompton Hospital. Clinical symptoms, co-morbidities and echocardiographic measurements of LV function were recorded before and at a median follow-up of 46 months after AVR. Pre-operative LV systolic dysfunction was defined as LV ejection fraction (EF) <50% and the post-op LV recovery as an increase of EF >10%.RESULTS: Following AVR peak aortic pressure gradient decreased and aortic valve area index increased (64+/-3 to 19+/-1 mm Hg and 0.30+/-0.01 to 0.89+/-0.03 cm(2)/m(2), p<0.001 for both). LV EF increased (from 45+/-1 to 54+/-2%; p<0.001) and the LV dimensions fell (LVEDD index: from 33+/-1 to 30+/-1 mm/m(2); and LVESD index: from 27+/-1 to 20+/-1 mm/m(2); p<0.01 for both). LV diastolic dysfunction improved as evidenced by the fall in E/A ratio (from 2.6+/-0.2 to 1.9+/-0.4) and prolongation of total filling time; (from 29.2+/-0.6 to 31.4+/-0.5 s/min, p=0.01 for both). Among all echocardiographic variables, LV dimensions (LVEDD index, OR 0.70, CI 0.52-0.97, p<0.05; LVESD index, OR 0.57, CI 0.40-0.85, p=0.005) were the two independent predictors of post-operative LV functional recovery on multivariate analysis. A cut off value of pre-operative LVESD index=or<27.5 mm/m(2) was 85% sensitive and 72% specific in predicting intermediate-term recovery of LV function after AVR (AUC, 0.72, p=0.002).CONCLUSION: LV functional recovery was evident in majority of aortic stenotic patients with LV dysfunction after aortic valve replacement. A lower prevalence of LV functional recovery in patients with large pre-operative LV end systolic dimension index might signify the loss of contractile reserve and thus predict post-operative functional recovery.
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| 26. |
- Ding, Wen-Hong, et al.
(författare)
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Predictors of survival after aortic valve replacement in patients with low-flow and high-gradient aortic stenosis
- 2009
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Ingår i: European Journal of Heart Failure. - : Oxford University Press. - 1388-9842 .- 1879-0844. ; 11:9, s. 897-902
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To identify predictors of survival following aortic valve replacement (AVR) in patients with low-flow and high-gradient aortic stenosis (AS).METHODS AND RESULTS: Eighty-six patients (aged 71 +/- 10 years) with severe AS [aortic valve mean pressure gradient >40 mmHg or valve area <1.0 cm(2)] and left ventricular (LV) dysfunction [ejection fraction (EF) <50%] underwent AVR. Cox proportional hazards were used to identify independent clinical and echocardiographic predictors of mortality. Operative (30-day) mortality was 10%. Peri-operative mortality was associated with lower mean LVEF, higher mitral E:A ratio, peak systolic pulmonary artery pressure (PSPAP), and serum creatinine (by 12%, 2.3, 28 mmHg, and 74 mmol/L, respectively, all P < 0.001), NYHA class III-IV (100 vs. 65%), concomitant CABG (89 vs. 55%), urgent surgery (78 vs. 35%), and longer bypass-time (by 28 min, all P < 0.05). Mortality at 4 years was 17%. Univariate predictors [hazard ratio (HR)] of 4-year mortality were: lower EF (HR 0.68 per % increase, P < 0.001), presence of restrictive LV filling (HR: 3.52, P < 0.001), raised PSPAP (HR: 1.07, P < 0.001), and CABG (HR: 4.93, P = 0.037). However, only low EF (<40%, HR 0.74, P = 0.030), the presence of restrictive filling (HR 1.77, P = 0.033), and raised PSPAP (>45 mmHg, HR 2.71, P = 0.010) remained as independent predictors after multivariate analysis. CONCLUSION: The severity of pre-operative systolic and diastolic LV dysfunction is the major predictor of mortality following AVR for low-flow and high-gradient AS.
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| 27. |
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| 28. |
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| 29. |
- Hsieh, Yves S-Y, et al.
(författare)
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Structure and bioactivity of the polysaccharides in medicinal plant Dendrobium huoshanense
- 2008
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Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier. - 0968-0896 .- 1464-3391. ; 16:11, s. 6054-68
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Tidskriftsartikel (refereegranskat)abstract
- Detailed structures of the active polysaccharides extracted from the leaf and stem cell walls and mucilage of Dendrobium huoshanense are determined by using various techniques, including chromatographic, spectroscopic, chemical, and enzymatic methods. The mucilage polysaccharide exhibits specific functions in activating murine splenocytes to produce several cytokines including IFN-gamma, IL-10, IL-6, and IL-1alpha, as well as hematopoietic growth factors GM-CSF and G-CSF. However, the deacetylated mucilage obtained from an alkaline treatment fails to induce cytokine production. The structure and bioactivity of mucilage components are validated by further fractionation. This is the first study that provides clear evidence for the structure and activity relationship of the polysaccharide in D. huoshanense.
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| 30. |
- Li, Wei, et al.
(författare)
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Congenital heart disease and heart failure.
- 2008
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Ingår i: Heart failure monitor. - 1470-8590. ; 6:1, s. 2-8
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Tidskriftsartikel (refereegranskat)abstract
- The syndrome of heart failure in adult non-congenital heart disease patients includes myocardial disease and ventricular dysfunction. In the presence of congenital abnormalities the cause of heart failure is often multi-factorial and can be a result of the underlying anomaly, surgical intervention, or ventricular dysfunction. Despite the possible clinical similarities, the two conditions are fundamentally different. In congenital heart disease the neurohormonal system is already abnormal even in the absence of clinical manifestations of heart failure and, in many cases, exercise intolerance is related to cyanosis. The approach to heart failure management in the two etiologies might be similar. Preventative attempts to preserve ventricular function in coronary or valve disease parallels early reparative therapy in congenital heart disease Pharmacological therapy is common for the two conditions, despite the limited number of evidence-based recommendations for congenital diseases. In drug-resistant patients, cardiac electrical resynchronization is an established therapy for treating ventricular asynchrony in non-congenital heart failure sufferers, but has only recently been adopted in selected congenital cases. Due to this, congenital heart disease patients are managed in highly specialized unites in close cooperation with cardiologists and surgeons. The ideal follow-up protocol for such patients remains to be determined, particularly in those individuals with subclinical signs of residual cardiac dysfunction. Heart Fail Monit 2008;6(1):2-8.
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| 31. |
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| 32. |
- Liu, Huibin, et al.
(författare)
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Probabilistic analytical target cascading : A moment matching formulation for multilevel optimization under uncertainty
- 2006
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Ingår i: Journal of mechanical design (1990). - : ASME International. - 1050-0472 .- 1528-9001. ; 128:4, s. 991-1000
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Tidskriftsartikel (refereegranskat)abstract
- Analytical target cascading (ATC) is a methodology for hierarchical multilevel system design optimization. In previous work, the deterministic ATC formulation was extended to account for random variables represented by expected values to be matched among subproblems and thus ensure design consistency. In this work, the probabilistic formulation is augmented to allow the introduction and matching of additional probabilistic characteristics. A particular probabilistic analytical target cascading (PATC) formulation is proposed that matches the first two moments of interrelated responses and linking variables. Several implementation issues are addressed, including representation of probabilistic design targets, matching responses and linking variables under uncertainty, and coordination strategies. Analytical and simulation-based optimal design examples are used to illustrate the new formulation. The accuracy of the proposed PATC formulation is demonstrated by comparing PATC results to those obtained using a probabilistic all-in-one formulation.
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| 33. |
- Löwemark, Ludvig, 1969-, et al.
(författare)
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New evidence for a glacioeustatic influence on deep watercirculation, bottom water ventilation and primaryproductivity in the South China Sea
- 2009
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Ingår i: Dynamics of atmospheres and oceans (Print). - : Elsevier. - 0377-0265 .- 1872-6879. ; 47:1-3, s. 138-153
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Tidskriftsartikel (refereegranskat)abstract
- We provide new evidence for the development of a stable estuarinecirculation characterized by stagnating water bodies, nutrientrecycling and increased primary productivity in the South ChinaSea (SCS) during glacial intervals. This circulation was caused bythe closure of the shallow and narrow straits connecting the SCSin the south and west. Our main evidence is derived from newlymeasured Mn concentrations and Mn/Al ratios in two sedimentcores from the northern and southeastern SCS covering the last500 ky. Concentrations and Mn/Al ratios of the redox sensitive elementMnshowclearglacial–interglacial cycles with maxima duringinterglacial periods and minima during glacial periods. These cyclesindicate ventilation cycles of the bottom water, and are connectedto the glacial–interglacial changes in sea level. In contrast, totalorganic carbon (TOC) concentrations display an opposite patternwith pronounced maxima during glacial times, especially in thesouthern part of the basin. The variations in TOC can be ascribed totwo factors. Firstly, variations in primary productivity are controlledby variations in the intensity of the winter monsoon. Secondlyto the degree of preservation of TOC controlled by variations inventilation, which in turn is ultimately controlled by sea level. Consequently, variations in TOC represent a superimposition ofprimarily sea level influenced preservation control and wintermonsoon driven variations in primary productivity intensity. Thedecrease in Mn correspond to times when sea level dropped40–60m below the present level. The larger amplitude of the variationsin TOC and Mn in the southern part of the basin compared tothe northern site suggest that oxygen depletion and nutrient recyclingwas stronger in the parts of the basin situated the furthest away from the only remaining opening to the open Pacific, the LuzonStrait.
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| 34. |
- Renna, Maurizio, et al.
(författare)
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Remifentanil plus low-dose midazolam for outpatient sedation in transesophageal echocardiography.
- 2008
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Ingår i: International journal of cardiology. - : Elsevier BV. - 1874-1754 .- 0167-5273.
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The search for optimal sedation for transesophageal echocardiography (TEE) continues. We hypothesized that the ultra-short acting opioid remifentanil combined with very low-dose midazolam would provide a better sedation and recovery profile compared to midazolam alone. METHODS: 41 consecutive outpatients scheduled for TEE received either IV midazolam (group M, 2.5 mg bolus plus 1 mg increments repeated as needed, n=18) or a combination of a low-dose IV bolus of midazolam (0.5 mg) plus an infusion of remifentanil (group RM, 0.1 mcg/kg/min, reduced to 0.08 mcg/kg/min after probe insertion, n=23). All patients received topical pharyngeal anesthesia with 2 puffs of lidocaine 4% spray. We recorded BP, SpO(2), HR, time-to-discharge (modified Aldrete score of 13), duration of procedure, resource utilization, complications, ease of probe introduction, ease and quality of the procedure. Patients' satisfaction with sedation was assessed using the Iowa Satisfaction with Anesthesia Scale (ISAS). RESULTS: Mean dose of midazolam in group M was 3.7+/-1.3 mg. Median time-to-discharge was significantly reduced in the RM group compared with the M group (5 (5-10) vs. 30 (5-240) min, p<0.0001), with 22 of the 23 group RM patients ready for "street discharge" within 5 min of removal of the TEE probe. Ease of probe insertion (p=0.001), resource utilization (p=0.0001), patient satisfaction (p=0.03) and overall ease and quality of the procedure (p=0.0001) were significantly better in the RM group than in the M group. No episodes of desaturation were observed. CONCLUSIONS: This is the first report of the use of an ultra-short acting opioid, remifentanil, combined with a low-dose of midazolam, as a sedative technique for outpatient TEE. In this pilot, non-randomized prospective study, remifentanil plus low-dose midazolam provided better sedation than our current practice of higher bolus doses of midazolam alone. This novel approach is associated with improved procedure tolerance, faster recovery and minimal resource utilization. A randomized, controlled study is under way to verify our preliminary results.
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| 35. |
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| 36. |
- Shieh, Jia-Min, et al.
(författare)
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Enhanced photoresponse of a metal-oxide-semiconductor photodetector with silicon nanocrystals embedded in the oxide layer
- 2007
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Ingår i: Applied Physics Letters. - : American Institute of Physics. - 0003-6951 .- 1077-3118. ; 90:5
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Tidskriftsartikel (refereegranskat)abstract
- The authors report a two-terminal metal-oxide-semiconductor photodetector for which light is absorbed in a capping layer of silicon nanocrystals embedded in a mesoporous silica matrix on p-type silicon substrates. Operated at reverse bias, enhanced photoresponse from 300 to 700 nm was observed. The highest optoelectronic conversion efficiency is as high as 200%. The enhancements were explained by a transistorlike mechanism, in which the inversion layer acts as the emitter and trapped positive charges in the mesoporous dielectric layer assist carrier injection from the inversion layer to the contact, such that the primary photocurrent could be amplified.
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| 37. |
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| 38. |
- Tångring, I., et al.
(författare)
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Strong 1.3-1.6 mu m light emission from metamorphic InGaAs quantum wells on GaAs
- 2005
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 86:17, s. 171902-
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate strong 1.3-1.6 mu m photoluminescence (PL) from InGaAs quantum wells (QWs) grown on alloy graded InGaAs buffer layers on GaAs by molecular beam epitaxy. The epistructures show quite smooth surfaces with an average surface roughness less than 2 nm. The PL intensity is comparable with those from InAs quantum dots and InGaAs QWs on GaAs, and InGaAsP QWs on InP at similar wavelengths, but stronger than those from GaInNAs QWs (at least 10 times higher at around 1.5-1.6 mu m). The excellent optical quality implies that the metamorphic approach could be a promising alternative to GaInNAs(Sb) QWs for 1.55 mu m lasers on GaAs.
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| 39. |
- Wang, Lihui, et al.
(författare)
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Function Block Design to Enable Adaptive Job Shop Operations
- 2007
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Konferensbidrag (refereegranskat)abstract
- Small volume and high product-mix contribute greatly to the complexity of job shop operations. In addition, shop floor uncertainty or fluctuation is another issue regularly challenging manufacturing companies, including job delay, urgent job insertion, fixture shortage, missing tool, and even machine breakdown. Targeting the uncertainty, we propose a function block based approach to generating adaptive process plans. Enabled by the function blocks, a so-generated process plan is responsive and tolerant to an unpredictable change. This paper presents in detail how a function block is designed and what it can do during process plan execution. It is expected that this new approach can largely enhance the dynamism of fluctuating job shop operations.
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| 40. |
- Wang, S M, et al.
(författare)
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Dilute nitrides and 1.3 mu m GaInNAs quantum well lasers on GaAs
- 2009
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Ingår i: MICROELECTRONICS JOURNAL. - : Elsevier BV. - 0026-2692. ; 40:3, s. 386-391
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Tidskriftsartikel (refereegranskat)abstract
- We present epitaxial growth of GaInNAs on GaAs by molecular beam epitaxy (MBE) using analog, digital and N irradiation methods. It is possible to realize GaInNAs quantum wells (QWs) with a maximum substitutional N concentration up to 6% and a strong light emission up to 1.71 mu m at 300 K. High quality 1.3 mu m GaInNAs multiple QW edge emitting laser diodes have been demonstrated. The threshold current density (for a cavity of 100 x 1000 mu m(2)) is 300, 300, 400 and 940 A/cm(2) for single, double, triple and quadruple QW lasers, respectively. The maximum 3 dB bandwidth reaches 17 GHz and high-speed transmission at 10 Gb/s up to 110 degrees C under a constant voltage has been demonstrated.
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| 41. |
- Wang, S M, et al.
(författare)
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Growth of GaInNAs and 1.3 mu m edge emitting lasers by molecular beam epitaxy
- 2009
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Ingår i: JOURNAL OF CRYSTAL GROWTH. - : Elsevier BV. - 0022-0248. ; 311:7, s. 1863-1867
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Tidskriftsartikel (refereegranskat)abstract
- We show that the use of a low growth rate combined with low N flux and RF power during molecular beam epitaxy (MBE) growth of dilute nitrides can efficiently enhance N incorporation while retaining good optical quality. A maximum light emission wavelength of 1.44 and 1.71 mu m has been obtained at 300 K from GaNAs and GaInNAs quantum wells, respectively. We demonstrate high-performance 1.3 pm GaInNAs multiple quantum well edge emitting lasers with record low threshold current densities, a 3 dB modulation bandwidth of 17 GHz at 300 K and capability of being modulated at 10 Gbit/s up to 110 degrees C without extra coolers. Our results show that MBE is an epitaxial technology suitable for the growth of dilute nitride materials and devices.
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| 42. |
- Zhao, Qingxiang, 1962-, et al.
(författare)
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Optical properties of GaInNAs/GaAs quantum well structures
- 2007
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 515:10, s. 4423-4426
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Tidskriftsartikel (refereegranskat)abstract
- The radiative recombination in GaInNAs/GaAs quantum well structures was investigated by low temperature optical spectroscopy. In the temperature region, below 100 K, we found that the observed transition energies strongly depend on the excitation intensity and the temperature, which is indicative of carrier localization. The degree of carrier localization depends on the In-concentration but is not significantly influenced by the N-concentration when the N-concentration exceeds 1.6%. Photoluminescence studies indicate that the degree of the carrier localization decreases with increasing In-concentration at a constant N-concentration. In addition, the experimental results show that carrier localization is strongly correlated to deep level emission. Through post-growth thermal treatment at 650 °C both carrier localization and deep level emission can be eliminated.
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