744 research outputs found
Cha guan. [3 & 4]
No full text1. 茶館 : side 3 -- 2. 茶館 : side 4.Section number supplied by cataloguer.Possibly reproduced from other commercial recording or radio broadcast (Pending for review)Electronic reproduction from Rulan Chao Pian Audio Cassette Collection.Spoken in Chinese.1. Cha guan : side 3 -- 2. Cha guan : side 4
Cha guan. [1 & 2]
No full text1. 茶館 : side 1 -- 2. 茶館 : side 2.Section number supplied by cataloguer.Possibly reproduced from other commercial recording or radio broadcast (Pending for review)Electronic reproduction from Rulan Chao Pian Audio Cassette Collection.Spoken in Chinese.1. Cha guan : side 1 -- 2. Cha guan : side 2
Fluoroethylene Carbonate-Based Electrolyte with 1 M Sodium Bis(fluorosulfonyl)imide Enables High-Performance Sodium Metal Electrodes
No full textSodium (Na) metal
anodes with stable electrochemical cycling have
attracted widespread attention because of their highest specific capacity
and lowest potential among anode materials for Na batteries. The main
challenges associated with Na metal anodes are dendritic formation
and the low density of deposited Na during electrochemical plating.
Here, we demonstrate a fluoroethylene carbonate (FEC)-based electrolyte
with 1 M sodium bis(fluorosulfonyl)imide (NaFSI) salt for the stable
and dense deposition of the Na metal during electrochemical cycling.
The novel electrolyte combination developed here circumvents the dendritic
Na deposition that is one of the primary concerns for battery safety
and constructs the uniform ionic interlayer achieving highly reversible
Na plating/stripping reactions. The FEC–NaFSI constructs the
mechanically strong and ion-permeable interlayer containing NaF and
ionic compounds such as Na2CO3 and sodium alkylcarbonates
COMPLEXITIES OF 3-MANIFOLDS FROM TRIANGULATIONS, HEEGAARD SPLITTINGS AND SURGERY PRESENTATIONS
No full textWe study complexities of 3-manifolds defined from triangulations, Heegaard splittings, and surgery presentations. We show that these complexities are related by linear inequalities, by presenting explicit geometric constructions. We also show that our linear inequalities are asymptotically optimal. Our results are used in another paper of the author to estimate Cheeger-Gromov L-2 rho-invariants in terms of geometric group theoretic and knot theoretic data.110sciescopu
Lean NOx Capture and Reduction by NH3 via NO+ Intermediates over H-CHA at Room Temperature
No full textThe oxidation of NO to NO2 and the subsequent reduction by NH3 via a NO+ intermediate over a proton-type chabazite zeolite (H-CHA) were investigated by the combination of in situ infrared (IR) spectroscopy and density functional theory (DFT) calculations. The in situ IR spectral results indicate that the NO' species formed under a flow of NO + O-2 at 27-250 degrees C are more stable at lower temperatures over both H-CHA and copper-cation-exchanged CHA zeolite (Cu-CHA). The Arrhenius plot (T = 27-120 degrees C) shows a negative apparent activation barrier energy (-11.5 kJ mol(-1)) for the formation of NO+ species under the NO + O(2 )flow over H-CHA. The time course of the IR spectra at 27 degrees C shows that NO is oxidized by O-2 to NO2 and then further converted via N2O4 to NO+ and NO3. The subsequent exposure to NH3 at 27 degrees C reduces the NO species to N-2. DFT calculations revealed that Bronsted acid sites in zeolite pores promote the dissociation of N2O4 intermediates into NO and NO3- species with a low activation barrier (15 kJ mol(-1)). Moreover, the computed activation barrier for the reduction of NO+ species by NH3 was considerably low (6 kJ mol(-1)). The experimental and theoretical results of this study demonstrate the high potential of Cu-free H-CHA zeolites for promoting lean NOx capture to form NO+ species and the subsequent reduction by NH3 at room temperature
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No full textDepartment of Energy Engineering (Battery Science and Technology)Aprotic electrolyte based lithium-oxygen batteries are of considerable interest due to its ultrahigh theoretical specific energy density (1675 mAh per gram of oxygen) against the present lithium-ion battery. In spite of the attractiveness of its high theoretical capacity, there is a number of drawbacks such as instability of electrochemical reaction of electrode and electrolytes. In order to overcome these parasitic reactions, significant efforts have been devoted to developing the key materials such as carbon-free air cathodes and high concentrated electrolytes. However, the CO2 evolution during the charging process and low ionic conductivity limit the ideal electrochemical reaction in aprotic electrolytes.
In this thesis, we applied the molten electrolyte based on nitrate-based electrolyte (Li/Na/K/Cs/Ca-NO3). The molten electrolyte, which has a eutectic point of 65???, has the advantages of high stability and high-temperature operation, thereby preventing detrimental solvent byproducts in lithium-oxygen batteries. We examined the Oxygen Evolution Reaction (OER) and Oxygen Reduction Reaction (ORR) on operating temperature using in situ pressure drop and gas analyses, Differential Electrochemical Mass Spectrometry (DEMS). Our results demonstrated that the Li2O2, a discharge product, formed a stable hexagonal morphology in the lithium-oxygen battery upon discharge process by scanning electron microscopy and X-ray diffraction techniques. Also, it leads to improved oxygen mobility at high temperature since a molten salt was used as the electrolyte in lithium-oxygen batteries. In addition, we found that kinetics are improved with increasing operating temperature in molten salt electrolyte cells.ope
Amenable L-2-Theoretic Methods and Knot Concordance
No full textWe reveal new structures in the topological knot concordance group. As a key ingredient, we develop obstructions using L-2-theoretic methods for amenable groups in Strebel's class recently introduced by Orr and the author. Concerning (h)-solvable knots, which are defined in terms of certain Whitney towers of height h in bounding 4-manifolds, we show the following: for any n>1, there are (n)-solvable but non-(n. 5)-solvable (and therefore nonslice) knots, which are not detected by prior methods using Cochran-Orr-Teichner L-2-signature obstructions as well as Levine algebraic obstructions and Casson-Gordon invariants.X1197sciescopu
High-Silica CHA Zeolite Membrane with Ultra-High Selectivity and Irradiation Stability for Krypton/Xenon Separation
No full textCapture and storage of the long-lived 85Kr is an efficient approach to mitigate the emission of volatile radionuclides from the spent nuclear fuel reprocessing facilities. However, it is challenging to separate krypton (Kr) from xenon (Xe) because of the chemical inertness and similar physical properties. Herein we prepared high-silica CHA zeolite membranes with ultra-high selectivity and irradiation stability for Kr/Xe separation. The suitable aperture size and rigid framework endures the membrane a strong size-exclusion effect. The ultrahigh selectivity of 51–152 together with the Kr permeance of 0.7–1.3×10−8 mol m−2 s−1 Pa−1 of high-silica CHA zeolite membranes far surpass the state-of-the-art polymeric membranes. The membrane is among the most stable polycrystalline membranes for separation of humid Kr/Xe mixtures. Together with the excellent irradiation stability, high-silica CHA zeolite membranes pave the way to separate radioactive Kr from Xe for a notable reduction of the volatile nuclear waste storage volume.ChemE/Catalysis Engineerin
Local structure and NO adsorption/desorption property of Pd2+ cations at different paired Al sites in CHA zeolite
No full textRecently, Pd-exchanged CHA zeolites (Pd-CHA) have attracted attention as promising passive NOx adsorbers (PNAs) for reducing NOx emissions during the cold start period of a vehicle engine. In this work, the relationship between the local structures and the NO adsorption/desorption properties of the Pd cations in CHA zeolites was investigated. Pd cation formation and NO adsorption were theoretically explored by density functional theory (DFT) calculations for different paired Al sites in six-/eight-membered rings (6MR/8MR). Furthermore, we prepared a series of Pd-CHAs with different Pd loadings (0.5-5.4 wt%) and evaluated their NO adsorption/desorption properties by in situ infrared (IR) spectroscopy and temperature-programmed desorption (TPD) measurements. The increase in the Pd loading resulted in a shift in the NO desorption temperature toward a higher temperature regime. This phenomenon was ascribed to the increase in the proportion of less stable Pd cations, resulting in improved NO adsorption. Furthermore, the effect of Al distribution on the NO adsorption property of Pd-CHA was examined using CHA zeolites containing different proportions of paired Al sites in 6MR while maintaining similar Si/Al ratios (Si/Al = 12.0-16.5). The present study, based on a combination of theoretical and experimental techniques, shows that the NO adsorption/desorption properties over Pd-CHA can be tuned by controlling the Pd loading amount and the type of paired Al sites
2018 CHA Prizes / Prix 2018 de la SHC
No full textThe CHA is pleased to inform its members of the 2018 shortlists
for its Sir John A. Macdonald Prize, given to the non-fiction
work of Canadian history judged to have made the most significant
contribution to the understanding of the Canadian past,
the prize is sponsored by Manulife Financial in the amount of
$5,000; and the Wallace K. Ferguson Prize, which recognizes the
outstanding scholarly book in a field of history other than Canadian
history. There prizes will be announced at the CHA Annual
Meeting at the University of Regina on Tuesday, May 29. This
year’s shortlisted books are (in alphabetical order by author)
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