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Ultraviolet light assisted heterogeneous Fenton degradation of tetracycline based on polyhedral Fe3O4 nanoparticles with exposed high-energy {110} facets
摘要： Polyhedral Fe3O4 nanoparticles (NPs) with exposed high-energy {110} facets were synthesized by hydro-thermal method using ferrous sulfate and sodium thiosulfate as precursor at 140 °C. The as-synthesized catalysts were characterized via X-ray powder diffraction (XRD), electro impedance spectra (EIS), scanning electron microscope (SEM), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM) at room temperature. The well-defined Fe3O4 NPs with exposed high-energy {110} facets distributed a wide size, and the percentage of {110} facets was approximately 38.5% for single Fe3O4 NPs crystal. The synergistic effect of UV irradiation and the polyhedral Fe3O4 NPs improved the photodegradation efficiency of tetracycline (TC). The degradation efficiency of polyhedral Fe3O4 NPs catalyzing UV-Fenton system reached 96.7% after 60 min reaction, which was more substantial than polyhedral Fe3O4/H2O2 system (40%) and spherical Fe3O4 NPs catalyzing UV-Fenton system (28%) after 60 min reaction. The TOC degradation efficiency reached 56.5% for polyhedral Fe3O4 NPs catalyzing UV-Fenton after 120 min reaction, while UV/H2O2 system and spherical Fe3O4 NPs catalyzing UV-Fenton was 36.0% and 22.1% respectively after 120 min reaction. Moreover, polyhedral Fe3O4 NPs catalyzing UV-Fenton system exhibited an extremely wide pH range (from 3.0 to 9.0) for efficient degradation of TC. Simultaneously, the extraordinary high degradation efficiency was based on 10 mM H2O2 concentration, which had low requirement for H2O2. Further, the polyhedral Fe3O4 NPs could be reused for five consecutive cycles while still achieving at 91.7% of its original degradation efficiency and recycled under a magnetic field along with excellent chemical stability. Ultraviolet light assisted heterogeneous Fenton in the polyhedral Fe3O4 NPs system improved the ?OH and O2?- production efficiency and Fe(III)/Fe(II) redox cycle, which consequently achieved an excellent degradation efficiency.
关键词： heterogeneous UV-Fenton,Polyhedral Fe3O4 nanoparticles,high-energy {110} facets,tetracycline degradation
更新于2025-11-14 17:03:37
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Unusual Electronic States and Superconducting Proximity Effect of Bi Films Modulated by NbSe2 Substrate
摘要： Heterostructures of two-dimensional layered materials can be functionalized with exotic phenomena that are unpresented with each constituting component. The interface effect plays a key role in determining the electronic properties of the heterostructure, whose characterization requires a correlation with the morphology with atomic-scale precision. Here, we report an investigation on the electronic properties of few-layer Bi(110) films mediated by NbSe2 substrate. By utilizing scanning tunneling microscopy and spectroscopy, we show a significant variation of the density of states at different Bi film thicknesses, resulting in an unusual superconducting proximity effect that deviates from the conventional monotonous decay behavior. Moreover, the electronic states of the Bi films are also prominently modulated by the Moiré pattern spatially. With first-principles calculations, we illuminate these findings as the results of covalent-like quasi-bonds formed at the Bi/NbSe2 interface, which profoundly alter the charge distributions in the Bi films. Our study indicates a viable way of modulating the electronic properties of ultrathin films by quasi-covalent interfacial couplings beyond conventional van der Waals interactions.
关键词： few-layers bismuth(110),two-dimensional heterostructures,thickness dependence,scanning tunneling microscopy,density functional theory calculations,covalent-like quasi-bonds,proximity effect
更新于2025-09-23 15:22:29
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[NanoScience and Technology] Silicene (Prediction, Synthesis, Application) || Si Nanoribbons: From 1D to 3D Nanostructures
摘要： In this chapter we give an overview on the theoretical and experimental investigations of one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) Si nanoribbons (SiNRs) formed on the anisotropic Ag(110) substrate surface. We start by introducing briefly free-standing silicene, a silicon layer with Si atoms arranged in honeycomb lattice, with hexagonal Si-rings as structural units. These hexagonal Si units are subsequently discussed as possible candidates to explain the atomic arrangement of the experimentally synthesized Si nanoribbons on Ag(110). This interpretation is supported by properties such as the presence of the 1D projection of the π and π* bands, forming the so-called “Dirac cones” at the K points of the Brillouin zone, the sp2-like nature of the Si valence orbitals, and the strong resistance against oxidation. Besides these results, the atomic structure as well as the origin of the electronic properties of these Si nanoribbons are still controversially debated in the literature. We address this discussion in the last part of the chapter before summarizing it.
关键词： Si nanoribbons,oxidation resistance,silicene,Ag(110) substrate,Dirac cones,sp2 hybridization
更新于2025-09-23 15:21:21
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Deuterium Kinetic Isotope Effect in the Photocatalyzed Dissociation of Methanol on TiO2(110)
摘要： Deuterium kinetic isotope effect (KIE) in the photochemistry of methanol on TiO2(110) has been studied to find the rate-determining step (RDS) and understand the reaction mechanism using two-photon photoemission spectroscopy (2PPE). Deuterium substitution of the methyl hydrogen has little effect on the kinetics of this reaction, suggesting that neither the break of the C-H(D) bond nor the transfer of H(D) atoms to the bridging sites is the RDS in the transformation of methanol into formaldehyde. In contrast, the reaction rate of MeOH is ~1.3 times of that of MeOD, suggesting that the cleavage of O-H(D) is the RDS in the photocatalyzed dissociation of methanol on TiO2(110). The results contradict with the common fact that C-H(D) is more difficult to break than O-H(D) based on ground state energetics, implying the involvement of photogenerated charge carriers in the reaction of C-H break whereas the cleavage of O-H is likely a thermal reaction. Difference in the activation energy of O-H and O-D dissociation reaction in the methanol/TiO2(110) system has been calculated based on the KIE measurements. Our work is consistent with the fact that methoxy is photocatalytically more reactive than methanol, and suggests that the conversion of methanol into methoxy is crucial in the photochemistry of methanol on TiO2(110) and probably other metal oxide semiconductor surfaces.
关键词： two-photon photoemission spectroscopy,photocatalyzed dissociation,Deuterium kinetic isotope effect,TiO2(110),methanol
更新于2025-09-23 15:21:01
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Optical Monitoring of Living Nerve Terminal Labeling in Hair Follicle Lanceolate Endings of the <em>Ex Vivo</em> Mouse Ear Skin
摘要： A novel dissection and recording technique is described for optical monitoring staining and de-staining of lanceolate terminals surrounding hair follicles in the skin of the mouse pinna. The preparation is simple and relatively fast, reliably yielding extensive regions of multiple labeled units of living nerve terminals to study uptake and release of styryl pyridinium dyes extensively used in studies of vesicle recycling. Subdividing the preparations before labeling allows test vs. control comparisons in the same ear from a single individual. Helpful tips are given for improving the quality of the preparation, the labeling and the imaging parameters. This new system is suitable for assaying pharmacologically and mechanically-induced uptake and release of these vital dyes in lanceolate terminals in both wild-type and genetically modified animals. Examples of modulatory influences on labeling intensity are given.
关键词： ear,Issue 110,Neuroscience,mechanosensation,hair follicle,electrophysiology,mouse,Lanceolate ending,skin
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE/MTT-S International Microwave Symposium - IMS 2019 - Boston, MA, USA (2019.6.2-2019.6.7)] 2019 IEEE MTT-S International Microwave Symposium (IMS) - W-band Finite Ground Coplanar Waveguide (FG-CPW) using Laser Enhanced Direct-Print Additive Manufacturing (LE-DPAM)
摘要： Design, fabrication, and measurement of finite ground coplanar waveguides (FG-CPWs) operating up to 110 GHz is demonstrated using additive manufacturing (AM) technology. FG-CPWs were fabricated using laser enhanced direct-print additive manufacturing, where laser-machining at 355 nm or 1064 nm wavelength was employed along with fused deposition modeling and micro-dispensing in a single digital manufacturing platform. This approach provides high dimensional accuracy that is required by mm-wave packaging systems. The characterization of laser machining at wavelengths of both 355 nm and 1064 nm was examined with specific focus on the feature size and dimensional accuracy. Several FG-CPW designs for 50 and 60 ohms are characterized and compared against a FG-CPW line on a commercially available calibration substrate. Attenuation as low as ~0.3 dB/mm at 110 GHz is achieved. To the best of the authors’ knowledge, this is the first reported experimental result for transmission lines at W-band using laser enhanced direct-print additive manufacturing (LE-DPAM).
关键词： transmission lines,W-band,laser machining,additive manufacturing,FG-CPW,millimeter wave,3D Printing,110 GHz
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Influence of Pressure History on Jet Dynamics in Lift Processes: Simulation and Experimental Analysis
摘要： The complexity of the physics involved in LIFT processes induces secondary phenomena after the first ejection for both Newtonian and non-Newtonian fluids. In this study, some fluid dynamics observed in experimental pictures is simulated. ? 2019 The Author(s)
关键词： 140.0140,100.0118,140.3390,110.0180,350.4600
更新于2025-09-12 10:27:22
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Terahertz intersubband absorption of GaN/AlGaN step quantum wells grown by MOVPE on Si(111) and Si(110) substrates
摘要： We demonstrate terahertz intersubband absorptions in nitride step quantum wells (SQWs) grown by metal organic vapor phase epitaxy simultaneously on two different substrate orientations [Si(111) and Si(110)]. The structure of the SQWs consists of a 3 nm thick Al0.1Ga0.9N barrier, a 3 nm thick GaN well, and an Al0.05Ga0.95N step barrier with various thicknesses. This structure design has been optimized to approach a ?atband potential in the wells to allow for an intersubband absorption in the terahertz frequency range and to maximize the optical dipole moment. Structural characterizations prove the high quality of the samples. Intersubband absorptions at frequencies of 5.6 THz (k (cid:2) 54 lm), 7 THz (43 lm), and 8.9 THz (34 lm) are observed at 77 K on both substrate orientations. The observed absorption frequencies are in excellent agreement with calculations accounting for the depolarization shift induced by the electron concentration in the wells.
关键词： Si(111),GaN/AlGaN,step quantum wells,intersubband absorption,Si(110),MOVPE,terahertz
更新于2025-09-12 10:27:22
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Simple model of the ground state and spin-orbital excitations of free and adsorbed Fe(II) phthalocyanine molecules
摘要： We investigate the ground state and low-energy spin-orbital excitations of a single iron(II) phthalocyanine molecule in isolation and on an oxidized Cu(110) surface. Considering the subspace spanned by the three lowest spin-triplet states of 3A2g and 3Eg symmetry, we diagonalize the Hamiltonian made of the anisotropic spin-orbit interaction and the ligand ?eld splitting (cid:2), de?ned as the energy difference between 3Eg and 3A2g. We ?nd that the ground state switches from a 3Eg-like state with large orbital moment and out-of-plane easy axis for (cid:2) < ?60 meV to a 3A2g-like singlet state with in-plane easy axis for (cid:2) > ?60 meV. The analysis of the ?rst excited states in the two regimes explains the zero-?eld splitting data reported for β-FePc as well as for FePc molecules adsorbed on an oxidized Cu(110) surface [N. Tsukahara et al., Phys. Rev. Lett. 102, 167203 (2009)]. Importantly, the calculated magnetic susceptibility obtained with the ab initio value (cid:2) = 93 meV compares remarkably well with the experimental data of β-FePc in the whole available temperature range of 1–300 K.
关键词： spin-orbital excitations,anisotropic spin-orbit interaction,oxidized Cu(110) surface,Fe(II) phthalocyanine,ligand ?eld splitting
更新于2025-09-10 09:29:36
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Unraveling the Structural and Electronic Properties of Graphene/Ge(110)
摘要： The direct growth of graphene on a semiconducting substrate opens a new avenue for future graphene-based applications. Understanding the structural and electronic properties of the graphene on a semiconducting surface is key for realizing such structures; however, these properties are poorly understood thus far. Here, we provide an insight into the structural and electronic properties of graphene grown directly on a Ge(110) substrate. Our scanning tunneling microscopy (STM) study reveals that overlaying graphene on Ge(110) promotes the formation of a new Ge surface reconstruction, i.e., a (6 × 2) superstructure, which has been never observed for a bare Ge(110) surface. The electronic properties of the system exhibit the characteristics of both graphene and Ge. The differential conductance (dI/dV) spectrum from a scanning tunneling spectroscopy (STS) study bears a parabolic structure, corresponding to a reduction in the graphene Fermi velocity, with exhibiting additional peaks stemming from the p-orbitals of Ge. The density functional theory (DFT) calculations confirm the existence of surface states due to the p-orbitals of Ge.
关键词： density functional theory calculations,scanning tunneling microscopy,Ge(110),scanning tunneling spectroscopy,Graphene,Ge surface reconstruction
更新于2025-09-10 09:29:36