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Jing-Hui Zhang, Tai Sun, Aping Niu, Yu-Mei Tang, Shun Deng, Wei Luo, Qun Xu, Dapeng Wei, De-Sheng Pei
Graphene quantum dots (GQDs) has been widely used in enormous fields, however, the inherent molecular mechanism of GQDs for potential risks in biological system is still elusive to date. In this study, the outstanding reduced graphene quantum dots (rGOQDs) with the QY as high as 24.62% were successfully synthesized by the improved Hummers method and DMF hydrothermal treatment approach. The rGOQDs were N-doped photoluminescent nanomaterials with functional groups on the surface. The fluorescent bio-imaging was performed by exposing zebrafish in different concentrations of the as-prepared rGOQDs, and the distribution of rGOQDs was successfully observed...
April 15, 2017: Biomaterials
Nishith K Das, Wissam A Saidi
Nickel-based alloys are widely applied materials in high-temperature applications because they exhibit superior corrosion resistance and mechanical properties. The effects of sulfur, which is invariably present in industrial atmospheres, on the early stages of oxidation of Ni-based surfaces are not well understood. Here we use density functional theory to investigate the interactions of sulfur, SO, and SO2 with the Ni(111) and Cr-doped Ni(111) surface and elucidate their electronic interactions and potential energy surfaces...
April 21, 2017: Journal of Chemical Physics
T V Can, R T Weber, J J Walish, T M Swager, R G Griffin
We present a pulsed dynamic nuclear polarization (DNP) study using a ramped-amplitude nuclear orientation via electron spin locking (RA-NOVEL) sequence that utilizes a fast arbitrary waveform generator (AWG) to modulate the microwave pulses together with samples doped with narrow-line radicals such as 1,3-bisdiphenylene-2-phenylallyl (BDPA), sulfonated-BDPA (SA-BDPA), and trityl-OX063. Similar to ramped-amplitude cross polarization in solid-state nuclear magnetic resonance, RA-NOVEL improves the DNP efficiency by a factor of up to 1...
April 21, 2017: Journal of Chemical Physics
Bartłomiej Kwiek, Michał Rożalski, Cezary Kowalewski, Marcin Ambroziak
OBJECTIVE: We wanted to asses the efficacy of large spot 532 nm laser for the treatment of facial capillary malformations with the use of three-dimensional (3D) image analysis. STUDY DESIGN AND METHODS: Retrospective single center study on previously non-treated patients with facial capillary malformations (CM) was performed. A total of 44 consecutive Caucasian patients aged 5-66 were included. Patients had 3D photography performed before and after and had at least one single session of treatment with 532 nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser with contact cooling, fluencies ranging from 8 to 11...
April 22, 2017: Lasers in Surgery and Medicine
Priyadarsini Swain, Suneel K Srivastava, Sanjeev K Srivastava
Metallic Ni1-x V x alloys exhibit a ferromagnetic to paramagnetic disordered quantum phase transition in bulk. Such a phase transition is accompanied by a quantum Griffiths phase (QGP), featuring fractional power-law temperature dependences of physical variables, like magnetic susceptibility and specific heat, at low temperatures. As nanoparticles (NP's) usually exhibit properties significantly different from their bulk counterparts, it is intriguing to explore the occurrence of quantum Griffiths phase in Ni1-x V x nanoalloys...
April 21, 2017: Scientific Reports
Yuan-Ting Lin, Paritosh Vilas Wadekar, Hsiang-Shun Kao, Yu-Jung Zheng, Quark Yung-Sung Chen, Hui-Chun Huang, Cheng-Maw Cheng, New-Jin Ho, Li-Wei Tu
In this report, ferromagnetic interactions in modulation-doped GaMnN nanorods grown on Si (111) substrate by plasma-assisted molecular beam epitaxy are investigated with the prospect of achieving a room temperature ferromagnetic semiconductor. Our results indicate the thickness of GaN layer in each GaN/MnN pair, as well as Mn-doping levels, are essential for suppressing secondary phases as well as enhancing the magnetic moment. For these optimized samples, structural analysis by high-resolution X-ray diffractometry and Raman spectroscopy verifies single-crystalline modulation-doped GaMnN nanorods with Ga sites substituted by Mn atoms...
December 2017: Nanoscale Research Letters
Tao Cheng, Baozhi Yu, Linli Cao, Huiyun Tan, Xinghua Li, Xinliang Zheng, Weilong Li, Zhaoyu Ren, Jinbo Bai
The ternary composite electrodes, nitrogen-doped graphene foam/carbon nanotube/manganese dioxide (NGF/CNT/MnO2), have been successfully fabricated via chemical vapor deposition (CVD) and facile hydrothermal method. The morphologies of the MnO2 nanoflakes presented the loading-dependent characteristics and the nanoflake thickness could also be tuned by MnO2 mass loading in the fabrication process. The correlation between their morphology and electrochemical performance was systematically investigated by controlling MnO2 mass loading in the ternary composite electrodes...
April 18, 2017: Journal of Colloid and Interface Science
G Krishnamurthy Grandhi, Ranjani Viswanatha
The success of heterostructure quantum dots in optoelectronic and photovoltaic applications is based on our understanding of photo-generated charge carrier localization. However, often the actual location of charge carriers in heterostructure semiconductors is quite different from their predicted positions leading to sub-optimal results. In this work, photoluminescence of Cu doped heterostructures have been used to study the charge localization of alloys, inverse type I, type II and quasi type II core/shell structures and graded alloys...
April 21, 2017: Journal of Physical Chemistry Letters
Yan Li, Sen Li, Yingmin Wang, Jun Wang, Hui Liu, Xinqian Liu, Lifeng Wang, Xiaoguang Liu, Wendong Xue, Ning Ma
In this work, phosphorus-doped graphene quantum dots (P-GQDs) with a high phosphorus doping content (>7 at%) are synthesized via an electrochemical approach. Sodium phytate (C6H6Na12O24P6), a green food antioxidant additive, is used as the electrolyte for providing both a phosphorus source and an electrolysis environment. The obtained P-GQDs exhibit excellent scavenging activity of free radicals, such as hydroxyl radicals (˙OH) and 2,2-diphenyl-1-picrylhydrazyl (DPPH). Combined with Raman, FT-IR, and XPS spectral analyses, the reason for high phosphorus content and the mechanism of free radical scavenging of P-GQDs are investigated in our work...
April 21, 2017: Physical Chemistry Chemical Physics: PCCP
Wanzhuo Ma, Tianshu Wang, Yan Zhang, Peng Liu, Yuwei Su, Qingsong Jia, Mingzhe Bi, Peng Zhang, Huilin Jiang
We propose and experimentally demonstrate a widely tunable mode-locked thulium-doped fiber laser. The laser can operate at both continuous-wave and mode-locked states at different pump power levels. A classic nonlinear polarization rotation structure is employed to obtain the passive mode-locked laser. A birefringence Lyot filter as a fiber comb filter is used to expand the tuning range. Thanks to the filtering component, the tuning range of the continuous-wave laser can reach 127 nm (1823-1950 nm). The tuning ranges of the single-wavelength and dual-wavelength mode-locked lasers are 94 nm (1835-1929 nm) and 87 nm (1831-1918 nm), respectively, with a 3...
April 20, 2017: Applied Optics
Naema Othman, Pierre Berini
We propose and investigate a Schottky contact detector where the contact metal is a nanoscale metal stripe waveguide supporting surface plasmons with strong localization along the Schottky contact. We consider Au for the metal stripe, p-doped silicon for the semiconductor, operation in the infrared (at λ<sub>0</sub>=1550  nm), and internal photoemission as the sub-bandgap detection mechanism. We find that the main surface plasmon mode of operation of the Au stripe exhibits diverging real and imaginary parts of n<sub>eff</sub> with decreasing stripe dimensions, commensurate with increasing confinement...
April 20, 2017: Applied Optics
Sean McDaniel, Fiona Thorburn, Adam Lancaster, Ronald Stites, Gary Cook, Ajoy Kar
We report fabrication and operation of multi-watt level waveguide lasers utilizing holmium-doped yttrium aluminum garnet (Ho:YAG). The waveguides were fabricated using ultrafast laser inscription, which relies on a chirped pulse ytterbium fiber laser to create depressed cladding structures inside the material. A variety of waveguides were created inside the Ho:YAG samples. We demonstrate output powers of ∼2  W from both a single-mode 50 μm waveguide laser and a multimode 80 μm waveguide laser. In addition, laser action from a co-doped Yb:Ho:YAG sample under in-band pumping conditions was demonstrated...
April 20, 2017: Applied Optics
Xiaoke Jin, Hafeezullah Memon, Wei Tian, Qinli Yin, Xiaofang Zhan, Chengyan Zhu
Synthetic fibers account for about half of all fiber usage, with applications in every textile field. The phenomenon of fiber composition not matching the label harms consumer interests and impedes market development. Hyperspectral imaging technology as a potential technique can be utilized to discriminate mass synthetic fibers rapidly and nondestructively and achieves the functions that traditional Fourier transform infrared instruments do not have. On the basis of investigating the impact of dope-dyeing and wrapping processes on spectra, the spectral features (from 900 to 2500 nm) of six categories of synthetic fibers were extracted with a hyperspectral imaging system...
April 20, 2017: Applied Optics
Tianxing Wang, Zhijun Yan, Chengbo Mou, Kaiming Zhou, Lin Zhang
Nanosecond passive Q-switching generation from an all-fiber erbium-doped laser with a UV inscribed 45° tilted fiber grating (TFG) is systematically demonstrated. The 45° TFG is employed as a polarizer together with two polarization controllers (PCs) to realize nonlinear polarization rotation (NPR). Because of the NPR effect, stable Q-switched pulses with an average output power of 17.5 mW, a single pulse energy of 72.7 nJ, a repetition rate of 241 kHz, a pulse width of 466 ns, and a signal to noise ratio (SNR) of 58...
April 20, 2017: Applied Optics
Haiyang Xu, Man Jiang, Chen Shi, Pu Zhou, Guomin Zhao, Xijia Gu
We report on the effects of spectral shaping of the output coupler fiber Bragg grating (OC-FBG) in a Yb-doped fiber laser on the laser emission spectrum for the purpose of inhabiting stimulated Raman scattering (SRS). The lasers with four different OC-FBGs were built and characterized. We found that the laser with a multiple reflection peak chirped-moiré OC-FBG produced a broad laser emission linewidth, which, in turn, led to about 100 times lower the SRS emission as compared with the laser with a 0.19 nm Gaussian-shaped OC-FBG...
April 20, 2017: Applied Optics
Philip Sullivan, Parmida Razavi
BACKGROUND: The coaching process is complex and dynamic. Coaches are known to affect athlete attitudes indirectly, through athletes' perceptions and interpretations. This process has been verified with a variety of ethical behaviors. OBJECTIVES: The current study investigated the relationships between athletes' perceived doping confrontation efficacy of their coaches and athlete's anti-doping attitudes. METHODS: A sample of athletes (N = 96) completed a version of the Doping Confrontation Efficacy Scale that was modified to assess their perception of their coaches' anti-doping confrontation efficacy, and the PEAS (Performance Enhancing Attitude Scale), which assessed their performance-enhancing attitudes...
April 21, 2017: Substance Use & Misuse
Tingting Luo, Yun Du, Zhongxian Qiu, Yanmei Li, Xiaofang Wang, Wenli Zhou, Jilin Zhang, Liping Yu, Shixun Lian
Eu(2+)-activated Ba2ZnS3 has been reported as a red phosphor with a broad emission band peaking at 650 nm under blue excitation for white-LED. In this study, Ba2ZnS3:Eu(2+), X(-) (X = F, Cl, Br, I) phosphors doped with halide ions were prepared by traditional high-temperature solid-state reaction. Phase identification of powders was performed by X-ray powder diffraction analysis, confirming the existence of single-phase Ba2ZnS3 crystals without dopant. The corresponding excitation spectra showed an additional broad band in the green region peaking at 550 nm when the phosphor was halogenated except by the smallest F(-)...
April 21, 2017: Inorganic Chemistry
Yoshinori Imai, Yuichi Sawada, Fuyuki Nabeshima, Daisuke Asami, Masataka Kawai, Atsutaka Maeda
Iron chalcogenide superconductors FeSe1-xTex are important materials for investigating the relation be-tween the superconductivity and the orbital and/or electronic nematic order, because the end member material FeSe exhibits a structural transition without a magnetic phase transition. However, the phase separation occurs in the region of 0.1 ≤ x ≤ 0.4 for bulk samples, and it prevents the complete understanding of this system. Here, we report the successful fabrication of epitaxial thin films of FeSe1-xTex with 0 ≤ x ≤ 0...
April 21, 2017: Scientific Reports
Lin Zhang, Xue Gao, Zhixuan Zhang, Mingbo Zhang, Yiqian Cheng, Jixin Su
No abstract text is available yet for this article.
April 21, 2017: Scientific Reports
Weilin Wang, Zhaofeng Wang, Jingjing Liu, Zhu Luo, Steven L Suib, Peng He, Guqiao Ding, Zhengguo Zhang, Luyi Sun
A hybrid photocatalyst based on anatase TiO2 was designed by doping TiO2 with sulfur and incorporating reduced graphene oxide (TiO2-S/rGO hybrid), with an aim to narrow the band gap to potentially make use of visible light and decrease the recombination of excitons, respectively. This TiO2-S/rGO hybrid was successfully synthesized using a one-pot hydrothermal method via single-step reaction. The structure and morphology of the TiO2-S/rGO hybrid catalyst was carefully characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS)...
April 21, 2017: Scientific Reports
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