345 research outputs found
Ship-in-a-bottle synthesis of amine-functionalized ionic liquids in NaY zeolite for CO<sub>2</sub> capture
No full textCO2 capture on solid materials possesses significant advantages on the operation cost, process for large-scale CO2 capture and storage (CCS) that stimulates great interest in exploring high-performance solid CO2 adsorbents. A ship-in-a-bottle strategy was successfully developed to prepare the [APMIM]Br@NaY host–guest system in which an amine-functionalized ionic liquid (IL), 1-aminopropyl-3-methylimidazolium bromide ([APMIM]Br), was in-situ encapsulated in the NaY supercages. The genuine host-guest systems were thoroughly characterized and tested in CO2 capture from simulated flue gas. It was evidenced the encapsulated ILs are more stable than the bulk ILs. These host–guest systems exhibited superb overall CO2 capture capacity up to 4.94 mmol g-1 and the chemically adsorbed CO2 achieved 1.85 mmol g-1 depending on the [APMIM]Br loading amount. The chemisorbed CO2 can be desorbed rapidly by flushing with N2 gas at 50°C. The optimized [APMIM]Br@NaY system remains its original CO2 capture capacity in multiple cycling tests under prolonged harsh adsorption-desorption conditions. The excellent physicochemical properties and the CO2 capture performance of the host-guest systems offer them great promise for the future practice in the industrial CO2 capture
Invasion possibility and potential effects of Rhus typhina on beijing municipality
No full textRhus typhina, an alien species introduced from North America, was identified as a main afforestation species in Beijing municipality. However, its invasiveness is still at odds. To clarify this problem, we applied the North American Screening System and the Australian Screening System to preliminarily predict its invasion possibility. Both screening systems gave the same recommendation to "reject". The geographical distribution was surveyed, with the population features of R. typhina against the native plant communities being assessed. With anthropogenic assistance, R. typhina has been scattered on almost all habitats from downtown to mountains, including roadsides, farmlands and protected areas. As a clonal shrub, R. typhina possessed a high spreading rate, varying from 6.3 m/3 years at sterile habitats to 6.7 m/3 years at fertile ones. Significantly lower species richness, individual density and diversity were observed in the R. typhina community than those of the native Vitex negundo Linn.var. heterophylla (Franch.) Rehd. community at both sterile and fertile habitats. Continual wide plantation of R. typhina may further foster its population expansion, which helps the species to overcome spatial isolation. The fact that each root fragment can develop into a new individual makes R. typhina very difficult to be eradicated once established. From a biological point of view, we believe that R. typhina is a plant invader in Beijing. We therefore suggest the government should remove the name of R. typhina from the main tree species list in afforesting Beijing.Rhus typhina, an alien species introduced from North America, was identified as a main afforestation species in Beijing municipality. However, its invasiveness is still at odds. To clarify this problem, we applied the North American Screening System and the Australian Screening System to preliminarily predict its invasion possibility. Both screening systems gave the same recommendation to "reject". The geographical distribution was surveyed, with the population features of R. typhina against the native plant communities being assessed. With anthropogenic assistance, R. typhina has been scattered on almost all habitats from downtown to mountains, including roadsides, farmlands and protected areas. As a clonal shrub, R. typhina possessed a high spreading rate, varying from 6.3 m/3 years at sterile habitats to 6.7 m/3 years at fertile ones. Significantly lower species richness, individual density and diversity were observed in the R. typhina community than those of the native Vitex negundo Linn.var. heterophylla (Franch.) Rehd. community at both sterile and fertile habitats. Continual wide plantation of R. typhina may further foster its population expansion, which helps the species to overcome spatial isolation. The fact that each root fragment can develop into a new individual makes R. typhina very difficult to be eradicated once established. From a biological point of view, we believe that R. typhina is a plant invader in Beijing. We therefore suggest the government should remove the name of R. typhina from the main tree species list in afforesting Beijing
Tribological properties of epoxy composite coatings reinforced with functionalized C-BN and H-BN nanofillers
No full textA series of epoxy resin (EP) composite coatings reinforced with functionalized cubic boron nitride (FC-BN) and functionalized hexagonal boron nitride (FH-BN) were fabricated successfully on 316L stainless steel by hand lay-up technique. The structure properties were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The morphologies were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, UMT-3 tribometer and surface profiler were used to investigate tribological behaviors of as-prepared composite coatings under dry friction and seawater conditions respectively. The results demonstrated that the presence of FC-BN or FH-BN fillers could greatly decrease the friction coefficient (COF) and wear rate of epoxy, in addition, composite coatings possess better tribological properties under seawater condition which was attributed to the lubricating effect of seawater. Moreover, FC-BN endows the composite coatings the highest wear resistance, and FH-BN / EP composite coatings exhibited the best friction reduction performance which is attributed to the self-lubricating performance of lamella structure for FH-BN sheet. (C) 2017 Elsevier B.V. All rights reserved
Photocatalytic degradation of imidazolium ionic liquids using dye sensitized TiO2/SiO2 composites
No full textPhotocatalytic degradation of imidazolium ionic liquids using dye sensitized TiO2/SiO2composites Huang, Lirong1; Yu, Yinghao1 Email author [email protected]; Fu, Chao2; Guo, Haiyang1; Li, Xuehui1 Source: RSC Advances, v 7, n 51, p 32120-32125, 2017; E-ISSN: 20462069; DOI: 10.1039/c7ra04939k; Publisher: Royal Society of Chemistry Author affiliations: 1 School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou; 510641, China 2 SINTEF Energy Research, Trondheim; 7465, Norway Abstract: Ionic liquids (ILs) are widely applied in diverse fields, however, ILs bring considerable challenges to the ecosystem when exposed to the environment due to their cytotoxicity and high chemical stability. It is thus increasingly important to investigate measures for the degradation of IL wastes in industrial processes. This paper presents the preparation of dye-sensitized photocatalysts (DCQ-TiO2/SiO2) and their applications in the degradation of 4 imidazolium ILs (1-butyl-3-methylimidazolium bromide, [BMIM]Br; 1-butyl-3-methylimidazolium tetrafluoroborate, [BMIM]BF4; 1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM]PF6; 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [BMIM]NTf2). The photocatalysts are prepared through in situ incorporation of TiO2into silica matrices and sensitization with 2,9-dichloroquinacridone (DCQ). The photocatalysts are then characterized with N2adsorption-desorption isotherm measurements, transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), elemental analysis and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). The results show that these photocatalysts exhibit high catalytic activities when they are applied in the degradation of imidazolium ILs. The degradation efficiency for [BMIM]Br can reach up to 95% under simulated sunlight irradiation in 180 minutes. The photodegradation intermediates of [BMIM]+are identified as harmless and easily biodegradable moieties. © 2017 The Royal Society of Chemistr
HUMAN CAPITAL AND CONSUMPTION RESPONSES TO POLICY EXPERIMENTS IN CHINA
No full textPh.DDOCTOR OF PHILOSOPHY (BIZ
Forecasting Extreme Precipitation Using k-nearest Forest Neighbors
No full textPrecipitation has high spatial and temporal uncertainty, which makes it challenging to predict. We focus specifically on extreme amounts of precipitation. The Royal Dutch Meteorological Institute (KNMI) uses a numerical model, approximating the solutions to partial differential equations, to forecast precipitation and other metrics about the weather. These forecasts have systematic errors, due to the model’s high sensitivity to input parameters. These errors can be corrected with statistical methods, by looking at the relation between the predicted and actual precipitation. We use a non-parametric regression set-up to estimate the conditional expectation of the weather given the forecasts of the numerical weather prediction model of the KNMI. Specifically, we focus on predicting the maximum precipitation in a three by three kilometers area in the Netherlands. There are several existing methods for solving non-parametric regression problems; in this thesis we will focus on k-nearest neighbors and random forests. A simulation study shows, however, that both these methods are not capable of dealing with more complex regression problems, such as forecasting extreme precipitation. Therefore, we are proposing a newly developed method, called k-nearest forest neighbors, which is a generalization of the random forests approach. This new method performs significantly better on the simulated data, compared to k-nearest neighbors and random forests. When applying the methods on a precipitation data set obtained from the KNMI, it also turns out that the method we developed has more predictive power than the numerical weather model and the existing non-parametric regression approaches
Data Supporting The Paper 'Removal of Pseudomonas Type IV Pili by a Small RNA Virus'
No full text<p>These files support the paper '<strong>Removal of Pseudomonas Type IV Pili by a Small RNA Virus</strong>' by J. Thongchol and Z. Yu, et al.</p>
<ul>
<li><strong>Mat_pilin_interaction.pdb</strong> is the atomic structure of PP7 Mat protein interacting with a single T4P pilin from RosettaDock.</li>
<li><strong>PP7_raw-images.zip</strong> contains all the fluorescence microscopy images used in this study. The raw images are organized based on data types (e.g., pilus detachment/RNA FISH) and corresponding figures in the paper (e.g., Fig1AB, as subfolders). Each subfolder, named after a specific figure, contains experiments from different dates, as indicated by the folder name, along with different biological replicates labeled as rep1 or rep2, etc.</li>
</ul>
Codes and Data Supporting The Paper 'Removal of Pseudomonas Type IV Pili by a Small RNA Virus'
No full text<p>These files support the paper '<strong>Removal of Pseudomonas Type IV Pili by a Small RNA Virus</strong>' by J. Thongchol and Z. Yu, et al.</p><ul><li><strong>Langevin_simulation.zip</strong> contains fortran source code used for Langevin simulation in the paper</li><li><strong>Mat_pilin_interaction.pdb</strong> is the atomic structure of PP7 Mat protein interacting with a single T4P pilin from RosettaDock.</li><li><strong>refSpot_v06.m</strong> is the custom MATLAB code to calculate the intensity and relative position of the fluorescent foci for RNA smFISH data.</li></ul>
Towards an Autonomous Knowledge System: Current Misconceptions and Improvement Pathways in China's Educational Research
No full textSince the 21st century, there have been remarkable achievements in the research on China's education, yet with potential misunderstandings and problems, such as the logical deduction of "mind is principle", the introduction of foreign research as "what is international is right", and the practical summary that is purely operational. These are closely related to the realistic background of the current education research, manifested as "a domestic-foreign intertwining", "a mix of pre-modern, modern and post-modern", and a research environment filled with materials but empty in spirit. At the same time, it is restricted by the development demand orientation of "rebuilding the spiritual roots, integrating ideas and actions, and forming a distinctive localized system". In order to carry out outstanding educational research and to tell well China's stories, we should properly handle the contradictions mentioned above, and take the following strategies of"returning to the origins to create, taking root and constructing, integrating China and the West, integrating theory and practice, and acting while reflecting"
Joint Subcarrier and CPU Time Allocation for Mobile Edge Computing
No full textIn mobile edge computing systems, mobile devices can offload compute-intensive tasks to a nearby \emph{cloudlet}, so as to save energy and extend battery life. Unlike a fully-fledged cloud, a cloudlet is a small-scale datacenter deployed at a wireless access point, and thus is highly constrained by both radio and compute resources. We show in this paper that separately optimizing the allocation of either compute or radio resource - as most existing works did - is highly \emph{suboptimal}: the congestion of compute resource leads to the waste of radio resource, and vice versa. To address this problem, we propose a joint scheduling algorithm that allocates both radio and compute resources coordinately. Specifically, we consider a cloudlet in an Orthogonal Frequency-Division Multiplexing Access (OFDMA) system with multiple mobile devices, where we study subcarrier allocation for task offloading and CPU time allocation for task execution in the cloudlet. Simulation results show that the proposed algorithm significantly outperforms per- resource optimization, accommodating more offloading requests while achieving salient energy saving.</p
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