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https://www.readbyqxmd.com/read/29775363/charge-transfer-processes-in-warm-dense-matter-selective-spectral-filtering-for-laser-accelerated-ion-beams
#1
J Braenzel, M D Barriga-Carrasco, R Morales, M Schnürer
We investigate, both experimentally and theoretically, how the spectral distribution of laser accelerated carbon ions can be filtered by charge exchange processes in a double foil target setup. Carbon ions at multiple charge states with an initially wide kinetic energy spectrum, from 0.1 to 18 MeV, were detected with a remarkably narrow spectral bandwidth after they had passed through an ultrathin and partially ionized foil. With our theoretical calculations, we demonstrate that this process is a consequence of the evolution of the carbon ion charge states in the second foil...
May 4, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29775247/microspheres-self-assembled-by-anti-site-defect-less-nanocrystal-lifepo4-c-rgo-to-achieve-both-high-rate-capability-and-high-tap-density-for-li-ion-batteries
#2
Hongbin Wang, Lijia Liu, Runwei Wang, Xiao Yan, Ziqi Wang, Jiangtao Hu, Haibiao Chen, Shang Jiang, Ling Ni, Hailong Qiu, Haitong Tang, Yingjin Wei, Zongtao Zhang, Qiu Shilun, Feng Pan
LiFePO4@C/rGO hierarchical microspheres with superior electrochemical activity and high tap density were first synthesized using a Fe3+-based single inorganic precursor (LiFePO4OH@RF/GO) obtained from a template-free self-assembly synthesis, following with direct calcination. The synthesis process requires no physical mixing step. The phase transformation path way from tavorite LiFePO4OH to olivine LiFePO4 upon calcination was determined by the in situ high temperature XRD technique. Benefitted from the unique structure of the material, these microspheres can be densely packed together, giving a high tap density of 1...
May 18, 2018: ChemSusChem
https://www.readbyqxmd.com/read/29774743/chiral-cryptates-derived-from-a-hexa-azamacrocycle
#3
Aleksandra Gerus, Katarzyna Ślepokura, Jarosław Panek, Aleksandra Turek, Jerzy Lisowski
The reactions of hexaazamacrocycle 1 with 2,6-bis(bromomethyl)pyridine or 2,6-bis[(tosyloxy)methyl)]pyridine in the presence of appropriate carbonates result in the formation of derivatives of cryptand 6 - enantiopure azacryptates of sodium and potassium. Crystal structures of these compounds indicate interaction of a metal ion with four pyridine nitrogen atoms and four tertiary amine atoms. The competition reactions monitored by NMR spectroscopy indicate preferential binding of Na+ over K+ as well as higher affinity of 6 for Na+ in comparison with the [2...
May 18, 2018: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29774421/a-fluorometric-aptasensor-for-methamphetamine-based-on-fluorescence-resonance-energy-transfer-using-cobalt-oxyhydroxide-nanosheets-and-carbon-dots
#4
Zeinab Saberi, Behzad Rezaei, Hossein Faroukhpour, Ali Ashghar Ensafi
Cobalt oxyhydroxide (CoOOH) nanosheets are efficient fluorescence quenchers due to their specific optical properties and high surface area. The combination of CoOOH nanosheets and carbon dots (CDs) has not been used in any aptasensor based on fluorescence quenching so far. An aptamer based fluorometric assay is introduced that is making use of fluorescent CDs conjugated to the aptamer against methamphetamine (MTA), and of CoOOH nanosheets which reduce the fluorescence of the CDs as a quencher. The results revealed that the conjugated CDs with aptamers were able to enclose the CoOOH nanosheets...
May 17, 2018: Mikrochimica Acta
https://www.readbyqxmd.com/read/29773822/origin-of-magnetic-properties-in-carbon-implanted-zno-nanowires
#5
Y F Wang, Y C Shao, S H Hsieh, Y K Chang, P H Yeh, H C Hsueh, J W Chiou, H T Wang, S C Ray, H M Tsai, C W Pao, C H Chen, H J Lin, J F Lee, C T Wu, J J Wu, Y M Chang, K Asokan, K H Chae, T Ohigashi, Y Takagi, T Yokoyama, N Kosugi, W F Pong
Various synchrotron radiation-based spectroscopic and microscopic techniques are used to elucidate the room-temperature ferromagnetism of carbon-doped ZnO-nanowires (ZnO-C:NW) via a mild C+ ion implantation method. The photoluminescence and magnetic hysteresis loops reveal that the implantation of C reduces the number of intrinsic surface defects and increases the saturated magnetization of ZnO-NW. The interstitial implanted C ions constitute the majority of defects in ZnO-C:NW as confirmed by the X-ray absorption spectroscopic studies...
May 17, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29773749/co-2-electroreduction-to-ethylene-via-hydroxide-mediated-copper-catalysis-at-an-abrupt-interface
#6
Cao-Thang Dinh, Thomas Burdyny, Md Golam Kibria, Ali Seifitokaldani, Christine M Gabardo, F Pelayo García de Arquer, Amirreza Kiani, Jonathan P Edwards, Phil De Luna, Oleksandr S Bushuyev, Chengqin Zou, Rafael Quintero-Bermudez, Yuanjie Pang, David Sinton, Edward H Sargent
Carbon dioxide (CO2 ) electroreduction could provide a useful source of ethylene, but low conversion efficiency, low production rates, and low catalyst stability limit current systems. Here we report that a copper electrocatalyst at an abrupt reaction interface in an alkaline electrolyte reduces CO2 to ethylene with 70% faradaic efficiency at a potential of -0.55 volts versus a reversible hydrogen electrode (RHE). Hydroxide ions on or near the copper surface lower the CO2 reduction and carbon monoxide (CO)-CO coupling activation energy barriers; as a result, onset of ethylene evolution at -0...
May 18, 2018: Science
https://www.readbyqxmd.com/read/29773342/sol-gel-electrospinning-preparation-of-hybrid-carbon-silica-nanofibers-for-extracting-organophosphorus-pesticides-prior-to-analyzing-them-by-gas-chromatography-ion-mobility-spectrometry
#7
Mohammad T Jafari, Mohammad Saraji, Mansoure Kermani
Carbon-silica hybrid nanofibers as high performance coatings for solid-phase microextraction fibers were used for analyzing some pesticides by using gas chromatography-corona discharge ion mobility spectrometry. To that end, the fibers were prepared by carbonizing sol-gel based on electrospun polyacrylonitrile and tetraethyl orthosilicate nanofibers as carbon and silica precursors, respectively. Different parameters affecting the electrospinning and the extraction processes including spinning distance, voltage, feeding rate, stirring rate, salt concentration, temperature and extraction time were optimized by response surface methodology...
May 8, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29772493/tissue-physiological-metabolic-adaptability-in-young-and-old-leaves-of-reed-phragmites-communis-in-songnen-grassland
#8
Rui Guo, Zhenzi Bai, Ji Zhou, XiuLi Zhong, FengXue Gu, Qi Liu, HaoRu Li
Common reed (Phragmites communis) is widely distributed as the dominant plant species in the Songnen Plain of China. The aim of this study was to investigate different physiological adaptive mechanisms to salinity tolerance between young and old leaves. The profiles of 68 metabolites were measured and studied in reed leaves by gas chromatography-mass spectrometer. The nitrogen, carbon, and pigment contents showed stronger growth inhibition for older leaves with salinity stress. In young leaves, high K+ contents not only promoted cell growth, but also prevented influx of superfluous Na+ ions in cells; the Ca2+ accumulation in old leaves implied that Ca2+ triggered the SOS-Na+ exclusion system and reduced Na+ toxicity...
May 9, 2018: Plant Physiology and Biochemistry: PPB
https://www.readbyqxmd.com/read/29772416/red-fluorescent-carbon-dots-with-phenylboronic-acid-tags-for-quick-detection-of-fe-iii-in-pc12-cells
#9
Changjian Li, Yueqi Wang, Xiaojie Zhang, Xueling Guo, Xiaoxuan Kang, Libo Du, Yang Liu
Carbon dots have attracted considerable attention in the field of biosensors and bioimaging because of their excellent optical performance and low toxicity. However, the cellular uptake of the reported carbon dots generally has a low efficiency, which limits their practical applications. In this study, we reported a novel red fluorescent sulfur and nitrogen co-doped carbon dots with small molecular phenylboronic acid tags (i.e. S, N-CDs-PBA). The S, N-CDs-PBA can be taken up rapidly by PC12 cells in twenty minutes and showed high sensitivity for the detection of Fe3+ ions...
May 9, 2018: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/29771503/internal-electric-field-modulation-in-molecular-electronic-devices-by-atmosphere-and-mobile-ions
#10
Prakash Chandra Mondal, Ushula M Tefashe, Richard L McCreery
The internal potential profile and electric field are major factors controlling the electronic behavior of molecular electronic junctions consisting of ~1-10 nm thick layers of molecules oriented in parallel between conducting contacts. The potential profile is assumed linear in the simplest cases, but can be affected by internal dipoles, charge polarization, and electronic coupling between the contacts and the molecular layer. Electrochemical processes in solutions or solid state are entirely dependent on modification of the electric field by electrolyte ions, which screen the electrodes and form the ionic double layers which are fundamental to electrode kinetics and widespread applications...
May 17, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29771119/engineering-hollow-carbon-architecture-for-high-performance-k-ion-battery-anode
#11
De-Shan Bin, Xi-Jie Lin, Yong-Gang Sun, Yan-Song Xu, Ke Zhang, An-Min Cao, Lijun Wan
K-ion batteries (KIBs) are now drawing increasing research interest as an inexpensive alternative to Li-ion batteries (LIBs). However, due to the large size of K+, stable electrode materials capable of sustaining the repeated K+ in-tercalation/deintercalation cycles are extremely deficient especially if a satisfactory reversible capacity is expected. Herein, we demonstrated that the structural engineering of carbon into a hollow interconnected architecture, a shape similar to the neuron-cell network, promised high conceptual and technological potential for a high-performance KIBs anode...
May 17, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29770819/a-porous-hierarchical-micro-nano-lini-0-5-mn-1-5-o-4-cathode-material-for-li-ion-batteries-synthesized-by-a-urea-assisted-hydrothermal-method
#12
Jiangfeng Wang, Xing Qin, Jianling Guo, Mushang Zhou, Bo Zong, Li Wang, Guangchuan Liang
A spinel LiNi0.5Mn1.5O4 cathode material was synthesized by a urea-assisted hydrothermal method followed by high-temperature calcination with a lithium source. The effects of the molar ratio of urea to transition metal ions (U/TM ratio) on the structure, morphology and electrochemical properties of the carbonate precursor and LiNi0.5Mn1.5O4 product were systematically investigated. The as-synthesized samples were characterized by XRD, FT-IR, SEM, TEM, a constant-current charge/discharge test, CV and EIS. XRD and FT-IR results show that the LiNi0...
May 17, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29770810/photoluminescent-carbon-dots-based-on-a-rare-3d-inorganic-organic-hybrid-cadmium-borate-crystal
#13
Kang Zhou, Wen-Jin Zhang, Yuan-Zhang Luo, Chun-Yang Pan
A 3D inorganic-organic hybridized skeleton cadmium borate [Cden][B5O8(OH)] (1) (en = ethylenediamine) has been solvothermally synthesized. By calcining it, specific shape carbon dots (C-dots) with abundant free radicals were observed. In addition, C-dots in the ethanol phase exhibited variable photoluminescence and showed rare turn on or off effects to Cr3+ ions and CdSe/ZnS quantum dots, but only a turn on effect to Cs+ ions and a turn off effect to CsPbBr3 quantum dots.
May 17, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29770687/spatial-associations-and-chemical-composition-of-organic-carbon-sequestered-in-fe-ca-and-organic-carbon-ternary-systems
#14
Tyler Sowers, Dinesh Adhikari, Jian Wang, Yu Yang, Donald L Sparks
Organo-mineral associations of organic carbon (OC) with iron (Fe) oxides play a major role in environmental OC sequestration, a process crucial to mitigating climate change. Calcium has been found to have high co-association with OC in soils containing high Fe content, increase OC sorption extent to poorly-crystalline Fe oxides, and has long been suspected to form bridging complexes with Fe and OC. Due to the growing realization that Ca may be an important component of C cycling, we launched a scanning transmission X-ray microscopy (STXM) investigation, paired with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, in order to spatially resolve Fe, Ca, and OC relationships and probe the effect of Ca on sorbed OC speciation...
May 17, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/29769673/thickness-independent-capacitance-of-vertically-aligned-liquid-crystalline-mxenes
#15
Yu Xia, Tyler S Mathis, Meng-Qiang Zhao, Babak Anasori, Alei Dang, Zehang Zhou, Hyesung Cho, Yury Gogotsi, Shu Yang
The scalable and sustainable manufacture of thick electrode films with high energy and power densities is critical for the large-scale storage of electrochemical energy for application in transportation and stationary electric grids. Two-dimensional nanomaterials have become the predominant choice of electrode material in the pursuit of high energy and power densities owing to their large surface-area-to-volume ratios and lack of solid-state diffusion1,2 . However, traditional electrode fabrication methods often lead to restacking of two-dimensional nanomaterials, which limits ion transport in thick films and results in systems in which the electrochemical performance is highly dependent on the thickness of the film1-4 ...
May 2018: Nature
https://www.readbyqxmd.com/read/29768832/design-of-sulphate-modified-solid-acid-catalysts-for-transesterification-of-diethyl-malonate-with-benzyl-alcohol
#16
K U Minchitha, H N Hareesh, K Venkatesh, M Shanty, N Nagaraju, N Kathyayini
Sulphate ion modified multiwalled carbon nanotubes (S-CNTs), mesoporous carbon (S-MC), zirconia (S-ZrO2), alumina (S-Al2O3) and silica (S-SiO2) were prepared by wet impregnation technique. The physico-chemical properties of the prepared materials were investigated by Powder-XRD, BET-Surface area and SEM-EDS analysis. Surface acidity of the materials was analyzed using TPD-NH3 and n-butyl amine titration methods. Catalytic activity of these materials was investigated in liquid phase transesterification of diethyl malonate with benzyl alcohol...
January 1, 2018: Journal of Nanoscience and Nanotechnology
https://www.readbyqxmd.com/read/29766603/characterization-of-aerosol-nitroaromatic-compounds-validation-of-an-experimental-method
#17
Mohammed Jaoui, Michael Lewandowski, John H Offenberg, Maribel Colon, Kenneth S Docherty, Tadeusz E Kleindienst
The analytical capabilities associated with the use of silylation reactions have been extended to a new class of organic molecules, nitroaromatic compounds (NACs). These compounds are a possible contributor to urban particulate matter of secondary origin which would make them important analytes due to their (1) detrimental health effects, (2) potential to affect aerosol optical properties, (3) and usefulness for identifying PM2.5 from biomass burning. The technique is based on derivatization of the parent NACs using N,O-bis-(trimethylsilyl)-trifluoro acetamide, one of the most prevalent derivatization reagent for analyzing hydroxylated molecules, followed by GC-MS using electron ionization (EI) and methane chemical ionization (CI)...
May 15, 2018: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/29766583/hollow-tinb2o7-c-spheres-with-superior-rate-capability-and-excellent-cycle-performance-as-anode-material-for-lithium-ion-batteries
#18
Guozhen Zhu, Qing Li, Renchao Che
TiNb2O7 with high charge/discharge voltage (1.65 V), long life span and excellent reversibility has become a new anode material for lithium ion batteries in recent years. However, the inherent poor electronic conductivity strictly limits its practical applications. Herein, we first report a hollow TiNb2O7@C spheres with carbon spheres as sacrificial template. The special hollow structure can effectively relieve the volume expansion during the repeated process of charging/discharging. The conductivity of hollow TiNb2O7 spheres can be greatly improved by the carbon layers uniformly coated outside the surface of TiNb2O7 spheres...
May 15, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29766179/piperidinium-ionic-liquids-as-electrolyte-solvents-for-sustained-high-temperature-supercapacitor-operation
#19
Jennifer Chapman Varela, Karthika Sankar, Alexander Hino, Xinrong Lin, Won-Seok Chang, David Coker, Mark Grinstaff
The synthesis and physicochemical properties of a series of non-flammable, thermally stable alkyl ether containing piperidinium ionic liquid electrolytes, containing lithium bis(trifluoromethanesulfonyl)imide, are described along with the superior performance of a lithium-ion supercapacitor containing a piperidinium electrolyte compared to a standard carbonate-based electrolyte at 100 °C.
May 16, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29766163/synchronous-synthesis-of-kirkendall-effect-induced-hollow-fese-2-c-nanospheres-as-anodes-for-high-performance-sodium-ion-batteries
#20
Yang Lan, Jianbin Zhou, Kangli Xu, Yue Lu, Kailong Zhang, Linqin Zhu, Yitai Qian
In this work, we have developed a simple and facile method to synchronously synthesize hollow FeSe2/C nanospheres using the Kirkendall effect. When evaluated as an anode for SIBs, the hollow FeSe2/C nanospheres exhibit a high discharge capacity retention of 474.1 mA h g-1 at 0.05 A g-1 (based on the calculation of FeSe2), which is very close to the theoretical capacity of FeSe2 (∼500 mA h g-1). Meanwhile, hollow FeSe2/C also has a superior rate capability of 364.5 and 316.5 mA h g-1 even at 2.0 and 5.0 A g-1, respectively...
May 16, 2018: Chemical Communications: Chem Comm
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