221,401 research outputs found
First year report_Honglin Xu
No full textThese videos are contraction function analysis of cardiac organoids. Cardiac organoids of 2500 μm diameter exhibiting spontaneous contraction(Myvideo_0). Transient calcium flux of cardiac organoids using 4 X (Myvideo_1) and 20 X (Myvideo_2) microscope
A Fourier-related FE2 Multiscale Model for Instability Phenomena of Long Fiber Reinforced Materials
No full textA Faboideae-specific floral scent betrays seeds to an important pest
No full textthe raw data for Xu et al. article: A Faboideae-specific floral scent betrays seeds to an important pes
A Novel FE2 Method Based Fourier Macroscopic Model for Instability Phenomena of Long Fiber Reinforced Composites
No full textCHIN 113-003: Elementary Chinese II - course syllabus
No full text3 pages.Submitted by Angela Kim ([email protected]) on 2010-02-19T17:03:25Z
No. of bitstreams: 1
CHIN 113-003_Elementary Chinese II_Svetlana G H Xu(3).pdf: 33074 bytes, checksum: 188fd39bec41b859fc182ca75f7f92ae (MD5)Made available in DSpace on 2010-02-19T17:03:25Z (GMT). No. of bitstreams: 1
CHIN 113-003_Elementary Chinese II_Svetlana G H Xu(3).pdf: 33074 bytes, checksum: 188fd39bec41b859fc182ca75f7f92ae (MD5)
Previous issue date: 2009-0
Dataset supporting publication "Femtosecond thulium fiber laser utilizing a gain-switched laser diode"
No full textThis dataset supports the publication: Femtosecond thulium fiber laser utilizing a gain-switched laser diode
AUTHORS: Ibrahim H. Abughazaleh, Matthew D. Gerard, Panuwat Srisamran, Duanyang Xu, Yongmin Jung, and Lin Xu
TITLE:Femtosecond thulium fiber laser utilizing a gain-switched laser diode
JOURNAL: optics letters
PAPER DOI IF KNOWN: https://doi.org/10.1364/OL.564071</span
Development of new proton conducting materials for intermediate temperature fuel cells
No full textThe work in this thesis mainly focuses on the preparation and characterization of several phosphates and solid oxide systems with the aim of developing new proton conducting materials for intermediate temperature fuel cells (ITFCs). Soft chemical methods such as sol-gel methods and conventional solid state methods were applied for the synthesis of these materials.
Aluminum phosphate obtained by a solution method is single phase and belongs to one of the Al(H₂PO₄)₃ allotropies with hexagonal symmetry. The material is stable up to 200°C and decomposes into Al(PO₃)₃ at a higher temperature. The electrical conductivity of pure Al(H₂PO₄)₃ is on the order of 10⁻⁶-10⁻⁷ S/cm, very close to the value for the known proton conductors AlH₃(PO₄)₂•3H₂O and AlH₂P₃O₁₀•2H₂O. Much higher conductivity is observed for samples containing even a trace amount of excess H₃PO₄. It is likely that the conduction path gradually changes from grain interior to the surface as the acid content increases. The conductivity of Al(H₂PO₄)₃-0.5H₃PO₄ exhibited a good stability over the measured 110 hours.
Although tin pyrophosphate (SnP₂O₇) has been reported to show a significantly high conductivity (~10⁻² S/cm) at 250°C in various atmospheres, we observed large discrepancies in the electrical properties of SnP₂O₇ prepared by different methods. Using an excess amount of phosphorous in the synthetic procedure generally produces SnP₂O₇ with much higher conductivity (several orders of magnitude higher) than samples with stoichiometric Sn:P ratios in their synthetic procedure. Solid state ³¹P NMR confirmed the presence of residual phosphoric acid for samples with excess starting phosphorous. Transmission Electron Microscope (TEM) confirmed an amorphous layer covered the SnP₂O₇ granules which was probably phosphoric acid or condensed phases. Thereby, it is quite likely that the high conductivity of SnP₂O₇ results mainly from the contribution of the residual acid. The conductivity of these samples exhibited a good stability over the measured 80 hours.
Based on the observations for SnP₂O₇, we developed a nano core-shell structure based on BPO₄ and P₂O₅ synthesised by solid state methods. The particle size of BPO₄ using this method varied between 10-20 nm depending on the content of P₂O₅. TEM confirmed the existence of an amorphous layer that is homogeneously distributed. The composite exhibits the highest conductivity of 8.8×10⁻² S/cm at 300°C in air for 20% extra P₂O₅ and demonstrates a good stability during the whole measured 110 hours. Polytetrafluoroethylene (PTFE) was introduced into the composites in order to increase malleability for fabrication. The conductivity and mechanical strength were optimized by adjusting the PTFE and P₂O₅ content. These organic-inorganic composites demonstrate much better stability at elevated temperature (250°C) over
conventional SiC-H₃PO₄-PTFE composites which are common electrolytes for phosphoric acid fuel cells (PAFCs). Fuel cells based on BPO₄-H₃PO₄-PTFE composite as the electrolyte were investigated using pure H₂ and methanol as fuels. A maximum power density of 320 mW/cm² at a voltage of 0.31 V and a maximum current density of 1.9 A/cm² at 200°C were observed for H₂/O₂ fuel cells. A maximum power density of 40 mW/cm² and maximum current of 300 mA/cm² 275°C were observed when 3M methanol was used in the cell.
Phosphoric acid was also introduced into materials with internal open structures such as phosphotungstic acid (H₃PW₁₂O₄₀) and heteropolyacid salt ((NH₄)₃PW₁₂O₄₀), for the purpose of acquiring additional connections. The hybrids obtained have a cubic symmetry with enlarged unit cell volume, probably due to the incorporation of phosphoric acid into the internal structures. Solid state ³¹P NMR performed on H₃PW₁₂O₄₀-xH₃PO₄ (x = 0-3) showed additional peaks at high acid content which could not assigned to phosphorus from the starting materials, suggesting a strong interaction between H₃PW₁₂O₄₀ and H₃PO₄. The conductivity of hybrids was improved significantly compared with samples without phosphoric acid. Fourier transform infrared spectra (FT-IR) suggest the existence of large amount of hydrogen bonds (OH••••O) that may responsible for the high conductivity. A H₂/O₂ fuel cell based on H₃PW₁₂O₄₀-H₃PO₄-PTFE exhibited a peak power density of 2.7 mW/cm² at 0.3 V in ambient temperature.
Solid oxide proton conductors based on yttrium doped BaZrO₃ were investigated by introducing potassium or lanthanum at the A-sites. The materials were prepared by different methods and were obtained as a single phase with space group Pm-3m (221). The unit cell of these samples is slightly smaller than the undoped one. The upper limit of solid solution formation on the A-sites for potassium is between 5 ~ 10% as introducing more K results in the occurrence of a second phase or impurities such as YSZ (yttrium stabilized zirconium). K doped Barium zirconates showed an improved water uptake capability even with 5% K doping, whereas for La doped ones, water uptake is strongly dependent on particle size and synthetic history. The conductivity of K doped BaZrO₃ was improved by a factor of two (2×10⁻³ S/cm) at 600°C compared with undoped material. Fuel cells based on Pt/Ba₀.₉₅K₀.₀₅Zr₀.₈₅Y₀.₁₁Zn₀.₀₄O[subscript(3-δ)]/Pt under humidified 5% H₂/air conditions gave a maximum power density 7.7 mWcm⁻² at 718°C and an interfacial resistance 4 Ωcm⁻². While for La doped samples, the conductivity was comparable with undoped ones; the benefits of introducing lanthanum at A-sites may not be so obvious as deficiency of barium is one factor that leads to the diminishing conductivity
Testudinella zhujiangensis Wei, De Smet & Xu 2010
No full textTestudinella zhujiangensis Wei, De Smet & Xu 2010 (Figs 6 C, 12–14) Redescription of trophi. Trophi malleoramate (Figs 12, 13). Frontal latero-ventral margins of rami with a large, quadratic and stout reinforced, caudally recurved alula (Figs 12–14: al). Median rami apophyses (Fig. 12 B: ra) weakly developed. Inner margins distal rami sections bearing 14–21 / 13–21 strongly webbed arched rami scleropili (Figs 12 B, 14 A: as). Frontal rami scleropili with fairly acute distal tip (Fig. 14 B: fs). Basal apophyses moderately developed (Fig. 13: ba). Fulcrum short with a distinct proximal opening frontally (Fig. 13: fo). Unci plates (Fig. 12 A: u) consist of 11–13 / 11–12 weakly curved and strongly webbed teeth. Each uncus has 3, occasionally 4, major teeth with moderately offset lanceolate heads. Minor teeth with lanceolate head bearing two minute lateral knobs at their base; the webbing almost extends up to the base of the heads. Crescent-shaped manubria are composed of a superimposed dorsal, median, ventral and small sub-ventral chamber (Fig. 12 B). Measurements. Trophi (N = 6): length × width 17.4–20.4 × 22.4–24.5 µm, ramus 10.7–12.1 µm, fulcrum 5.2– 6.1 µm, largest major tooth 10.0– 10.6 µm, manubrium 10.7–12.4 µm.Published as part of Wei, Nan, De, Willem H. & Xu, Runlin, 2011, Two new brackish-water species of Testudinella (Rotifera: Testudinellidae) from Qi'ao Island in the Pearl River estuary, China, with a key to marine and brackish-water Testudinella, pp. 41-56 in Zootaxa 3051 on page 51, DOI: 10.5281/zenodo.20778
Innovative Approach to Anti-BEPS and the Coherence of International Tax Law
Get PDFThis dissertation is comprised of three articles: Avi-Yonah, Reuven,. co-author. Evaluating BEPS: A Reconsideration of the Benefits Principle and Proposal for UN Oversight. H. Xu, co-author. Harv. Bus. L. Rev. 6, no. 2 (2016): 185-238 Reuven S. Avi-Yonah & Haiyan Xu, A Global Treaty Override? The New OECD Multilateral Tax Instrument and Its Limits, 39 Mich. J. Int\u27l L. 155 (2018). Avi-Yonah, Reuven S. China and BEPS. Haiyan Xu, co-author. Laws 7, no. 1 (2018): 4-30
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
