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Light-emitting diodes

Kireesan Sornalingam, Andrew McDonagh, John L Zhou, Md Abu Hasan Johir, Mohammad Boshir Ahmed
Gold-modified TiO2 (Au-TiO2) photocatalysts were utilised for the degradation of estrone (E1), a major endocrine disrupting chemical in water and wastewater. Au-TiO2 catalysts were synthesised by a deposition-precipitation method with gold loadings of 0-8% (wt%). The Au-TiO2 nanocomposite exhibited superior activity compared to P25 TiO2 under UVA (λ=365nm), cool white (λ>420nm) and green (λ=523nm) light emitting diodes (LEDs), for treating 1mgl(-1) of E1. The 4wt% Au loading was found to produce the best photocatalytic activity with a rate constant of 2...
August 16, 2017: Science of the Total Environment
Weili Chen, Hojeong Yu, Fu Sun, Akid Ornob, Ryan Brisbin, Anurup Ganguli, Vinay Kumar Vemuri, Piotr Strzebonski, Guangzhe Cui, Karen J Allen, Smit A Desai, Weiran Lin, David M Nash, David Hirschberg, Ian Brooks, Rashid Bashir, Brian T Cunningham
New tools are needed to enable rapid detection, identification, and reporting of infectious viral and microbial pathogens in a wide variety of point-of-care applications that impact human and animal health. We report the design, construction, and characterization of a platform for multiplexed analysis of disease-specific DNA sequences that utilizes a smartphone camera as the sensor in conjunction with a handheld "cradle" that interfaces the phone with a silicon-based microfluidic chip embedded within a credit card-sized cartridge...
August 18, 2017: Analytical Chemistry
Way-Ren Huang, Chia-Jen Hsieh, Ke-Chiun Chang, Yen-Jo Kiang, Chien-Chung Yuan, Woei-Chyn Chu
This study proposes a different angle to social network analysis that evaluates patent value and explores its influencing factors using the network centrality and network position. This study utilizes a logistic regression model to explore the relationships in the LED industry between patent value and network centrality as measured from out-degree centrality, in-degree centrality, in-closeness centrality, and network position, which is measured from effect size. The empirical result shows that out-degree centrality and in-degree centrality have significant positive effects on patent value and that effect size has a significant negative effect on patent value...
2017: PloS One
Antonio A García, Lina S Franco, Miguel A Pirez-Gomez, José L Pech-Pacheco, Jorge F Mendez-Galvan, Carlos Machain-Williams, Lourdes Talavera-Aguilar, José H Espinosa-Carrillo, Miriam M Duarte-Villaseñor, Christian Be-Ortiz, Luz E Espinosa-de Los Monteros, Ariel Castillo-Pacheco, Julian E Garcina-Rejon
Antibody detection and accurate diagnosis of tropical diseases is essential to help prevent the spread of disease. However, most detection methods lack cost-effectiveness and field portability, which are essential features for achieving diagnosis in a timely manner. To address this, 3D-printed oblate spheroid sample chambers were fabricated to measure green light scattering of gold nanoparticles using an optical caustic focus to detect antibodies. Scattering signals of 20-200 nm gold nanoparticles using a green laser were compared to green light emitting diode (LED) light source signals and to Mie theory...
August 17, 2017: Diagnostics
Li Song, Xiaoyang Guo, Yongsheng Hu, Ying Lv, Jie Lin, Zheqin Liu, Yi Fan, Xingyuan Liu
Efficient inorganic perovskite light-emitting diodes (PeLEDs) with an ultrathin perovskite emission layer (~30 nm) were realized by doping Lewis base Polyethylene Glycol (PEG) into CsPbBr3 films. PEG in the perovskite films not only physically fills the crystal boundaries, but also interacts with the perovskite crystals to passivate the crystal grains, reduce nonradiative recombination and ensure the efficient luminance and high efficiency. As a result, promoted brightness, current efficiency (CE) and external quantum efficiency (EQE) were achieved...
August 17, 2017: Journal of Physical Chemistry Letters
Manuel Zimmer, Fabian Dietrich, Daniel Volz, Stefan Bräse, Markus Gerhards
The electronic ground and excited state structure of two binuclear Cu(I)-NHETPHOS-complexes, which are promising to be implemented in OLEDs (organic light emitting diodes), is investigated by a combination of the time-resolved step-scan FTIR technique and quantum chemical calculations at the DFT level. In contrast to the usual application of step-scan FTIR spectroscopy in solution the herein presented analyses are performed in solid phase, i.e. the Cu(I) complexes are embedded in a KBr matrix (KBr pellet). Applying "solid state" time-resolved step-scan FTIR spectroscopy is of great importance for transition metal complexes, since oftentimes their photophysical properties change when moving from solid to dissolved samples...
August 16, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Quyet Van Le, Jong Beom Kim, Soo Young Kim, Byeongdu Lee, Dong Ryeol Lee
In this study, we have intensively investigated the effect of the reaction temperature of hot-injection method on the structural properties of CsPbX3 (X: Br, I, Cl) perovskite nanocrystals (NCs) using the small- and wide-angle X-ray scattering. Furthermore, light emitting diodes (LEDs) performance as well as photoluminescence characteristics for high-efficient LEDs is compared with reaction temperature. It is confirmed that the size of the NCs decreased as the reaction temperature decreased, resulting stronger quantum confinement...
August 16, 2017: Journal of Physical Chemistry Letters
Sedat Bilge, Attila Aydin, Meltem Bilge, Cemile Aydin, Erdem Cevik, Mehmet Eryilmaz
OBJECTIVE: Strict blackout discipline is extremely important for all military units. To be able to effectively determine wound characteristics and perform the necessary interventions at nighttime, vision and light restrictions can be mitigated through the use of tactical night vision goggles (NVGs). The lamp of the classical laryngoscope (CL) can be seen with the naked eye; infrared light, on the other hand, cannot be perceived without the use of NVGs. The aim of the study is to evaluate the safety of endotracheal intubation (ETI) procedures in the dark under tactically safe conditions with modified laryngoscope (ML) model...
July 2017: Military Medicine
Xinwei Chen, Si-Lu Tao, Cong Fan, Dongcheng Chen, Ling Zhou, Hui Lin, Cai-Jun Zheng, Shi-Jian Su
Ternary bulk heterojunction (BHJ) is a brilliant photovoltaic technology for improving the performance of organic solar cells (OSCs), since the light absorption range can be significantly extended by using multiple donors or acceptor materials. In this paper, coumarin7 (C7), a small organic molecule typical led used in organic light-emitting diodes, was initially exploited as second electron-donor component in ternary bulk heterojunction OSCs along with conventional blend system spolythieno[3,4-b]-thiophene/benzodithiophene(PTB7) and [6,6]-phenyl-C71 -butyric acid methyl(PC71 BM)...
August 15, 2017: ACS Applied Materials & Interfaces
Yoon-Ho Choi, Dong-Hyeok Lim, Jae-Hun Jeong, Dambi Park, Kwang-Sik Jeong, Minju Kim, Aeran Song, Hee-Suk Chung, Kwun-Bum Chung, Yeonjin Yi, Mann-Ho Cho
Transition metal dichalcogenides (TMDCs) are promising next-generation materials for optoelectronic devices because, at sub-nanometer thicknesses, they have a transparency, flexibility, and band gap in the near-infrared to visible light range. In this study, we examined continuous, large-area MoSe2 film, grown by molecular beam epitaxy on an amorphous SiO2/Si substrate, which facilitated direct device fabrication without exfoliation. Spectroscopic measurements were implemented to verify the formation of a homogeneous MoSe2 film by performing mapping on the micrometer scale and measurements at multiple positions...
August 15, 2017: ACS Applied Materials & Interfaces
Marcelo Santos Coelho, Steven J Card, Peter Z Tawil
OBJECTIVES: The evaluation of iatrogenic dentinal defects in extracted teeth may be influenced by extraction forces and prolonged dry times. The purpose of this study was to compare the presence of dentinal defects in freshly extracted, periodontally compromised teeth with those in a group of teeth with uncontrolled extraction forces and storage time. MATERIALS AND METHODS: The experimental group consisted of eighteen roots obtained from teeth extracted due to periodontal reasons with class II or III mobility...
August 2017: Restorative Dentistry & Endodontics
Naji Al-Dubaili, Na'il Saleh
The excited-state lifetimes of the anticoagulant drug warfarin (W) in water and in the absence and presence of methyl-β-cyclodextrins (Me-β-CD) were recorded using time-resolved fluorescence measurements. Selective excitation of the open and cyclic protonated isomers of W were acquired with laser emitting diodes (LED) producing 320 and 280 nm excitation pulses, respectively. Formation of the inclusion complex was checked by UV-visible absorption spectroscopy, and the values of binding constants (2.9 × 10³ M(-1) and 4...
August 11, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Chengyi Xu, Yanhua Song, Hongxia Guan, Ye Sheng, Pingchuan Ma, Xiuqing Zhou, Zhan Shi, Haifeng Zou
A series of emission-tunable Na1-xAl1+2xSi1-2xO4:xCe(3+)/Tb(3+)/Dy(3+) phosphors were synthesized via a high temperature solid-state reaction method. Luminescence properties, energy transfer from Ce(3+) to Tb(3+) or Dy(3+) ions, color tuning and thermal stability were systematically investigated. Particularly, the charge compensating defect generated by doping of rare earth ions was remedied through Al(3+) substituted Si(4+). Meanwhile, the emission intensity was significantly improved. The presence and content of various elements were demonstrated through data combined with the crystallographic data from Rietveld refinements and the analysis of SEM and mapping for each element...
August 11, 2017: Physical Chemistry Chemical Physics: PCCP
Xianbo Qiu, Shiyin Zhang, Lanju Mei, Di Wu, Qi Guo, Ke Li, Shengxiang Ge, Xiangzhong Ye, Ningshao Xia, Michael G Mauk
Almost all the reported capillary convective polymerase chain reaction (CCPCR) systems to date are still limited to research use stemming from unresolved issues related to repeatability, reliability, convenience, and sensitivity. To move CCPCR technology forward toward commercialization, a couple of critical strategies and innovations are discussed here. First, single- and dual-end heating strategies are analyzed and compared between each other. Especially, different solutions for dual-end heating are proposed and discussed, and the heat transfer and fluid flow inside the capillary tube with an optimized dual-end heating strategy are analyzed and modeled...
March 2017: Biomicrofluidics
Alexander M Dreyer, Christoph S Herrmann, Jochem W Rieger
Steady-state visual evoked potentials (SSVEPs) have been widely employed for the control of brain-computer interfaces (BCIs) because they are very robust, lead to high performance, and allow for a high number of commands. However, such flickering stimuli often also cause user discomfort and fatigue, especially when several light sources are used simultaneously. Different variations of SSVEP driving signals have been proposed to increase user comfort. Here, we investigate the suitability of frequency modulation of a high frequency carrier for SSVEP-BCIs...
2017: Frontiers in Human Neuroscience
Yu-Sian Li, Jia-Ling Liao, Ke-Ting Lin, Wen-Yi Hung, Shih-Hung Liu, Gene-Hsiang Lee, Pi-Tai Chou, Yun Chi
Tetradentate chelates bearing tripodal arranged terpyridine and a functional pyrazole unit (i.e., L1-H and L2-H) were employed in preparation of Ir(III) complexes [Ir(L1)Cl2] (1) and [Ir(L2)Cl2] (2); subsequent chloride-to-bipyrazolate substitution gave [Ir(L1)(bipz)] (3) and [Ir(L2)(bipz)] (4). Single-crystal X-ray structural studies on 1 and 3 showed the possession of a tetradentate chelate, whereas the remaining cis-sites are occupied by either dual chlorides or the bipz chelate, respectively. Sky blue organic light-emitting diode with peak efficiencies (10...
August 10, 2017: Inorganic Chemistry
Huan Wang, Dong Ha Kim
While the field of perovskite-based optoelectronics has mostly been dominated by photovoltaics, light-emitting diodes, and transistors, semiconducting properties peculiar to perovskites make them interesting candidates for innovative and disruptive applications in light signal detection. Perovskites combine effective light absorption in the broadband range with good photo-generation yield and high charge carrier mobility, a combination that provides promising potential for exploiting sensitive and fast photodetectors that are targeted for image sensing, optical communication, environmental monitoring or chemical/biological detection...
August 10, 2017: Chemical Society Reviews
Daeseong Jung, Jun-Ho Choi, Soocheol Kim, Suho Ryu, Wonchan Lee, Jong-Seok Lee, Chulmin Joo
We present a portable multi-contrast microscope capable of producing bright-field, dark-field, and differential phase contrast images of thin biological specimens on a smartphone platform. The microscopy method is based on an imaging scheme termed "color-coded light-emitting-diode (LED) microscopy (cLEDscope)," in which a specimen is illuminated with a color-coded LED array and light transmitted through the specimen is recorded by a color image sensor. Decomposition of the image into red, green, and blue colors and subsequent computation enable multi-contrast imaging in a single shot...
August 8, 2017: Scientific Reports
Ashutosh Kumar, Musharib Khan, Liping Fang, Irene M C Lo
TiO2-based photocatalysis offers certain advantages like rapid degradation and mineralization of organic compounds. However, the practical applicability of photocatalysts in degradation of pharmaceuticals and personal care products (PPCPs) is still restricted by challenges including their limited photocatalytic activity under visible light and difficulty in their separation from suspension. To overcome these challenges, a visible-light-driven magnetic N-TiO2@SiO2@Fe3O4 nanophotocatalyst was developed through fine-tuning the pertinent factors (calcination temperature, Fe3O4 loading, and nitrogen doping) involved during synthesis process, on the basis of degradation of ibuprofen (a typical PPCP)...
July 24, 2017: Journal of Hazardous Materials
Ran Cao, Tao Zhou, Bin Wang, Yingying Yin, Zuqing Yuan, Congju Li, Zhong Lin Wang
Currently, a triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG) have been hybridized to effectively scavenge mechanical energy. However, one critical issue of the hybrid device is the limited output power due to the mismatched output impedance between the two generators. In this work, impedance matching between the TENG and EMG is achieved facilely through commercial transformers, and we put forward a highly integrated hybrid device. The rotating-sleeve triboelectric-electromagnetic hybrid nanogenerator (RSHG) is designed by simulating the structure of a common EMG, which ensures a high efficiency in transferring ambient mechanical energy into electric power...
August 7, 2017: ACS Nano
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