135,351 research outputs found
Breaking New Ground in East Asia Library History
No full textReview of Peter X. Zhou. Collecting Asia: East Asian Libraries in North America (2010).Published in H-Net Reviews in the Humanities and Social Sciences and available at: http://www.h-net.org/reviews/showrev.php?id=32231March 201
The concept of peace in the Tao Te Ching
Full text linkThis thesis represents a first attempt to analyze Lao Tzu's main method of resolving the social and political problems in Ch'un Ch'iu and Warring States Periods. Lao Tzu, the founder of Taoism, suggested many solutions that could bring an end to the conflicts and to the ending of the disunity of China. Examples of these include the reform or abolishment of some ancient Chinese institutions as well as new principles for the enhancement and preservation of life. All these ideas were to become crystallised in Tao Te Ch'ing, which became an important religious text. In particular, the aspect of Lao Tzu's methods for solving the social and political problems of China in the Warring States Period needs more attention. In each chapter of the Tao Te Ch'ing there was a main emphasis on peace as the main method of developing social cohesion and as a cure to all fundamental human problems. Therefore, Lao Tzu's ideas about peace and his methods of solving the problems of the Warring States period are significant and from the main focus of the thesis
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
Tao, Khanh Lam, June 7, 2021 [Interview]
No full textKhanh Lam Tao was interviewed on June 7, 2021, by Devin McKinney about her early life, her education at Gettysburg College, and her professional path since graduation.Grzybowski, Joseph; Parker, William; Maynes, JeffreyGordon A. Haaland Years; Katherine H. Will Years
Multi-exponential inversion of induced polarization relaxation signal of shaly sand
No full textThe induced polarization (IP) decay curve of natural shaly sand can be modeled as a weighted superposition of exponential relaxations with different relaxation time constant. The IP relaxation time spectrum, which is defined as plot of weight versus the relaxation time constant, has been previously demonstrated as a significant tool for capillary pressure curve, pore size distribution and permeability of reservoir. Earlier works successfully used singular value decomposition (SVD) method to extract the relaxation time spectra from the decay data. However, those works were obtained from the measured data with very high signal to noise ratio (SNR). The developed algorithm is suitable for these data. But for the practice use downhole, the obtained decay data have low SNR and then the obtained spectra from these decay data using the algorithm may be unstable and invalid.
In this work, the method of regularization is applied to extracting continuous IP relaxation time spectra from decay data. The regularization operator is a unit matrix. To illustrate the influences of regularization parameters on the inversion of IP relaxation time spectra, the used decay data is generated from starting relaxation time spectra. Varying levels of random noise are added to these data sets and the IP relaxation time spectra are calculated for comparison to the starting distribution.
Results show that for the data contains noise, the obtained spectra of the simulated decay data become smoother with increasing the regularization parameter. There exists an optimum regularization parameter which can be used to get the most reasonable spectrum. The logarithmical optimum parameter decreases linearly with increasing the logarithmical SNR. The developed algorithm and the prediction of the optimum parameter are very reasonable for the real rock sample. The results also show that the best number of relaxation distribution points ranges from 16 to 64.Unpublishedope
Taphrocerus tao Zayas 1988
No full text<i>Taphrocerus tao</i> Zayas <p>(Fig. 4)</p> <p> <i>Taphrocerus tao</i> Zayas 1988: 41.</p> <p>Type locality: CUBA: Pinar del Río Province, Viñales. Zayas (1988: 42) cited three syntype specimens from the type locality. The photographed syntype is a male.</p> <p> This species is most similar to <i>Taphrocerus timidus</i> Chevrolat based on the information provided by Fisher (1925) on the Caribbean species, and USNM specimens identified by Fisher as <i>T. timidus</i> (from Cuban localities: C. Jatiponico; Nagua, Oriente; and Cienfuegos, Soledad). The USNM specimens have a slightly angulate lateral pronotal margin and a vaguely defined prehumeral carina at the posterior angle of the pronotum which appear to be shared by <i>T. tao</i>. <i>Taphrocerus tao</i> could be a synonym of <i>T. timidus</i>, but only examination of the actual specimens, including genitalia, in a comparative context, will resolve the identity of <i>T. tao</i> with certainty.</p>Published as part of <i>Barman, E. H., Michat, M. C., Alarie, Y. & Wolfe, G. W., 2007, Figs. 16 – 17. 16 in A Description of the First Instar of Hoperius planatus Fall, 1927 (Coleoptera: Dytiscidae: Colymbetinae: Colymbetini), with Phylogenetic Implications, pp. 334-338 in The Coleopterists Bulletin 24 (3)</i> on page 337, DOI: 10.1649/0010, <a href="http://zenodo.org/record/10110742">http://zenodo.org/record/10110742</a>
Update on TAO moored ORG array
Full text linkDuring the Coupled Ocean Atmosphere Response Experiment (COARE) six TAO moorings were equipped with optical rain gauges (ORG's). In late 1993 moorings deployed on the equator at 154E and 157.5E were recovered and not redeployed as they were augmentations to the TAO array for COARE only. In December 1993, four TAO moorings were equipped with ORG's: one each at 2N, 156E and 2S, 156E and ORG doublets on the equator at 0, 156E and 0, 165E. The 2N, 156E mooring has been lost. By the end of April all sites will have been serviced and six refurbished sensors will again be deployed in the same locations
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Serum of TAO patients inhibits HUVEC migration.
No full text<p>Scratch wound closure assay; a single scrape was made across a confluent HUVEC monolayer (Baseline). The extent of regrowth to close the scratch wound was measured after 6 hours (6 h) incubation in medium containing 10% of serum of TAO patients or controls. Data are presented as medians, with 25/75 percentiles (boxes) and 10/90 percentiles (bars), (n = 12 in each group). ***P<0.001; NS = nonsmokers, S = smokers, TAO = Thromboangiitis obliterans.</p
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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