587 research outputs found
Nano-self-assembly in Mn-based spinels through solid state process
No full textTransition-metal oxides characterized with anisotropic d-orbital electrons are subject to intense discussion in strongly correlated electron systems, ranging from colossal magnetoresistance (CMR) to high temperature superconductivity (HTSC). The orbital degree of freedom often underpins complex physical properties and a variety of extraordinary phenomena while coupling with charge, spin and lattice. In this thesis, we demonstrate a fascinating example of orbital-related physical properties in Mn-based spinels. The strong octahedral preference of Jahn-Teller ions Mn3+ results in simultaneous chemical and structural phase separation into Mn-poor (cubic) and Mn-rich (tetragonal) regions, forming two types of rectangular nanorods with cross section checkerboard-like (CB). Because of the pioneering discovery of checkerboards in the nonmagnetic ZnMnxGa1-xO4, we chose to study two magnetic spinel systems: (1) Mg(MnxFe1-x)O4, where unfortunately only poorly-ordered magnetic nano CBs were observed; and (2) Mn-doped CoFe2O4, the nano CBs with distinct magnetic properties and tunable sizes achieved here are highly ordered, exhibiting a nearly ideal architecture for the patterned perpendicular recording medium. The evolution of such compositional separation and topological nanoscale ordering is reasonably understood based on a three dimensional (3D) phase-field microelasticity (PFM) model.Ph.D.Includes bibliographical references.by Chenglin Zhan
Efficient solar domestic and industrial sewage purification via polymer wastewater collector
No full textWater pollution caused by domestic and industrial sewage exacerbates the shortage of freshwater, with major negative consequences for society and the environment. Solar-to-steam energy conversion systems, namely the extraction of steam using solar energy, are a promising eco-friendly and cost-effective approach for water purification. However, current technologies still exhibit low efficiency and high energy consumption. Here we report a polymer wastewater collector with a cross-scale hierarchical structure based on Defective polypyrrole-modified activated carbon paper substrate (DPAC), and its use for sporadic wastewater collection and efficient solar-driven sewage purification. Strong absorption of the solar spectrum at an arbitrary incident angle was achieved, which continuously provides heat for evaporation. Water molecules are prone to aggregate around the defective polypyrrole networks, where the generated heat is directly transferred to the water molecules, resulting in a low heat loss and high conversion efficiency for purifying seawater. In addition, DPAC exhibits superior domestic and industrial sewage evaporation rates of 1.37 and 1.28 kg m−2h−1 under one sun irradiation with corresponding solar-to-steam conversion efficiencies of 91.8% and 85.8%, respectively. The principle of this solar steam generator may provide useful insights towards the efficient and energy-saving treatment of domestic and industrial sewage
Lithium dendrite inhibition via 3D porous lithium metal anode accompanied by inherent SEI layer
No full textLithium (Li) metal anodes have been considered as the ultimate anode materials for the next-generation rechargeable batteries. However, uneven dendrite formation and anode volume expansion still can put a brake on the development of Li metal anode. Here, freestanding three-dimensional Li metal foam accompanied by inherent solid electrolyte interphase (SEI) capsulation formed by template-free chemical etching is constructed to promote the uniform lithium deposition and suppress dendritic Li growth. Contrary to planar Li metal foil, the 3D porous Li matrix can buffer the volume change and guide Li deposition inside its porous structure. Moreover, the encapsulated artificial SEI layer, which efficiently uniform the diffusion of Li ions on the interface, enables deeply deposited Li metal. Benefiting from the unique deposition kinetics, the Li plating/stripping process based on our strategy can be deeply cycled at various current densities with low overpotential between 1.0 and 20.0 mA cm−2 and achieve long lifetime up to 350 h. Moreover, Li metal batteries with LiNiCoMnO2 (Ni:Co:Mn=1:1:1) cathode exhibit excellent electrochemical performance at high current density and active material loading for more than 20.4 mg cm−2. In terms of both porous Li matrix and inherent dense SEI layer, our cell greatly suppresses the gassing process and reduces heat generation, further demonstrating the reliability and security of the batteries
STUDY ON USING DAYLIGHT AS LIGHTING SYSTEM ACCORDING TO VARIOUS SUN ANGLES
No full text<p>In recent years, it has become more common for us to rely on artificial lighting during the daytime even when daylight can be obtained at places such as office buildings. Using daylight may pave the way for energy saving system of office buildings, and the development of lighting devices which actively utilize daylight is attracting attentions. However, there are few lighting devices that are able to take light based on the movement of the sun. As the sun moves throughout the day, the magnitude and direction of light entering the room change also. Due to this, it is difficult to control the amount of light entering the room. In this study, we aim to solve this problem by installing several blind reflectors on the window whereby the reflectors are able to change its angle according to the movement of the sun. By having these reflectors, the light will be directed to the room ceiling and diffused light from the ceiling will be used to create an optimal room lighting environment. This system was simulated, assessed for all seasons on sunny days in the simulator and its energy saving effect was evaluated. With the obtained result, we hope to contribute in the promotion of a greener society.</p>
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CCDC 1813736: Experimental Crystal Structure Determination
No full textRelated Article: Bin Gu, Chenglin Sun, James C. Fettinger, William H. Casey, Alla Dikhtiarenko, Jorge Gascon, Kamila Koichumanova, Karthick Babu Sai Sankar Gupta, Hero Jan Heeres, Songbo He|2018|Chem.Commun.|54|4148|doi:10.1039/C8CC01363B,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
CCDC 1813736: Experimental Crystal Structure Determination
No full textXETWIF : tetrakis(μ-oxido)-dodecakis(μ-2-hydroxyethan-1-olato)-dodecakis(μ-hydroxo)-trideca-aluminium(iii) heptakis(chloride) monohydrate unknown solvate Space Group: F d 3 m (227), Cell: a 24.6762(11)Å b 24.6762(11)Å c 24.6762(11)Å, α 90° β 90° γ 90° Related Article: Bin Gu, Chenglin Sun, James C. Fettinger, William H. Casey, Alla Dikhtiarenko, Jorge Gascon, Kamila Koichumanova, Karthick Babu Sai Sankar Gupta, Hero Jan Heeres, Songbo He|2018|Chem.Commun.|54|4148|doi:10.1039/C8CC01363B,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Nanomembranes Based on Nickel Oxide and Germanium as Anode Materials for Lithium-Ion Batteries
No full textRechargeable lithium-ion batteries are now attracting great attention for applications in portable electronic devices and electrical vehicles, because of their high energy density, long cycle and great convenience. For new generations of rechargeable lithium-ion batteries, they applied not only to consumer electronics but also especially to clean energy storage and hybrid electric vehicles. Therefore, further breakthroughs in electrode materials that open up a new important avenue are essential. Graphite, the most commonly used commercial anode material, has a limited reversible lithium intercalation capacity (372 mAh g-1). In this regard, tremendous efforts have been made towards even further improving high capacity, excellent rate capability, and cycling stability by developing advanced anode materials.
This work focuses on the lithium storage properties of nickel oxide (NiO) and germanium (Ge) nanomembranes anodes mainly fabricated by electron-beam evaporation. Specifically, NiO is selected for conversion-type material because of high theoretical specific capacity of 718 mAh g-1 and easily obtained material. The resultant curved NiO nanomembranes anodes exhibit ultrafast power rate of 50 C (1 C = 718 mA g-1) and good capacity retention (721 mAh g-1, 1400 cycles). Remarkably, multifunctional Ni/NiO hybrid nanomembranes were further fabricated and investigated. Benefiting from the advantages of the intrinsic architecture and the electrochemical catalysis of metallic nickel, the hybrid Ni/NiO anodes could be tested at an ultrahigh rate of ~115 C. With Ge as active alloying-type material (1624 mAh g-1), the effect of the incorporated oxygen to the lithium storage properties of amorphous Ge nanomembranes is well studied. The oxygen-enabled Ge (GeOx) nanomembranes exhibit improved electrochemical properties of highly reversible capacity (1200 mAh g-1), and robust cycling performance
The Measurement of Integrated Human Service Network (The Children's Treatment Network of Simcoe York)
No full textTitle: The Measurement of Integrated Human Service Network (The Children's Treatment Network of Simcoe York), Author: Chenglin Ye, Location: ThodeCommunity-based human services have traditionally been provided by autonomous
service agencies. They have their own funding source and independent process.
Integration has been advocated as a key strategy to integrate different agencies together
to provide multiple services for a targeted community. The Children's Treatment Network
(CTN) of Simcoe York is a network of agencies and organizations providing services to
children with multiple needs and their families in Simcoe County and York Region. This
study was designed to evaluate the different levels of integrated service approaches for
children on outcomes. The study consisted of two parts: phase I and phase II
measurement. Our project covered phase I measurement with the following objectives. Clinically,
we aimed to evaluate agencies' integration in the network, promote discussion, and
determine any interrelationship between a network's integration and its functioning. The
statistical objectives were to quantify the network integration for agency, to represent the
overall integration, to quantify the association between network's integration and
functioning and to assess the sensitivity of results. We measured agencies' integration through measuring its agreement in
collaboration with other agencies in the network. The higher agreement in collaboration
indicates a better services integration. We defined four different agreement measures
from different perspectives. The agreement based on group's perception was defined to
be the primary measure. We used mean difference, percentage and the Kappa statistic
to measure the agreement for each agency. Correlation and regression analyses were
applied in investigating the association between network's integration and its functioning. The sensitivity of the results was analyzed by examining the re-sampling bias of
bootstrapping regression models. Agreement measures were consistent for each agency. In Simcoe, agencies had
an average agreement 0.874 (S.D. 0.213) in mean difference, 46.63 (S.D. 12.91) in
percentage and 0.258 (S.D. 0.143) in Kappa. Agencies of York had average agreements
of 0.662 (S.D. 0.204), 49.36 (S.D. 13.06) and 0.282 (S.D. 0.121), respectively. Agency
10 and 33 in Simcoe and Agency 14 in York were found to have the highest agreement.
Agency 3 and 21 in Simcoe and Agency 8 and 9 in York, on the other hand, were found
to have the lowest agreement. Different graphical displays illustrated that the overall
agreement in collaboration was low and the agencies in York generally had a higher
agreement. Correlation analysis showed that synergy and agencies' perception of pros
and cons were significantly correlated with the primary percentage agreement. In
regression analysis, we did not find any significant functioning component. However,
synergy was found to be much more associated with agreement than the other
components. The estimates were 11.48% (-1.03%, 24.00%) and 11.21% (-2.48%,
24.90%) in un-weighted and weighted models respectively. Bootstrapping regression
analysis showed that the results were robust to a change of sample. We concluded that the level of integration of CTN was low because the agencies
generally had poor agreement in collaboration. Synergy was the most important
component associated with the network's integration. Other functioning components
detected were also associated with the integrating process but were less clinically
important. We discussed the statistical approaches used in other contexts and some of
their strength and weaknesses. We also considered some key limitations of the study.
This study was a baseline measurement of CTN of Simcoe York for further analysis. The
results provided a basis for future enhancement of integration of the network. Our
experiences also provided ideas for improving design and analysis in integrated network
measurement.ThesisMaster of Science (MS
RETRACTED ARTICLE: Stem-like cells of various origins showed therapeutic effect to improve the recovery of spinal cord injury
No full textStem-like cells of various origins showed therapeutic effect to improve the recovery of spinal cord injuryWe, the Editors and Publisher of the journal Artificial Cells, Nanomedicine, and Biotechnology, have retracted the following article:Jian Kang, Chenglin Zhang, Zhongzheng Zhi, Yingjie Wang, Jingdong Liu, Furong Wu & Guanghui Xu (2020) Stem-like cells of various origins showed therapeutic effect to improve the recovery of spinal cord injury, Artificial Cells, Nanomedicine, and Biotechnology, 48:1, 627–638, DOI: 10.1080/21691401.2020.1725031Following publication of this article, concerns about the scientific integrity of the article were brought to the Publisher and Editor’s attention.Whilst the authors were fully cooperative with the investigation and able to answer some questions, they were unable to provide the original western blot data.In addition, concerns remain about the methods used for the animal experiments. As these concerns directly impact the reported results and conclusions, the Editor and Publisher have agreed to retract the article to ensure correction of the scholarly record. The corresponding author has been informed. The authors do not agree with the retraction.We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’
Simulation of land use changes using cellular automata and artificial neural network
No full textThis paper presents a method integrating artificial neural network (ANN) in cellular automata (CA) to simulate land use changes in Luxembourg and the areas adjacent to its borders. The ANN is used as a base of CA model transition rule. The proposed method shows promising results for prediction of land use over time. The ANN is validated using cross-validation technique and Receiver Operating Characteristic (ROC) curve analysis, and compared with logit model and a support vector machine approach. The application described in this paper highlights the interest of integrating ANNs in CA based model for land use dynamic simulation.Artificial neural network; Cellular automata; Modelling; Land use changes; Spatial planning and dynamics
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