bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaporative Cooling Hydrogel Packaging for Storing Biologics Outside of the Cold Chain
Authors: Ferber Shiran , Behrens Adam M. , McHugh Kevin J. , Rosenberg Evan M. , Linehan Allison R. , Sugarman James L. , Jayawardena Hapuarachchige Surangi N. , Langer Robert , Jaklenec Ana 
Published: May 2018

AbstractStabilizing thermolabile pharmaceuticals outside of the cold chain has the potential to alleviate some of the logistical and monetary burden of providing health care access in the developing world. Evaporative cooling hydrogel packaging is designed to extend the storage stability of existing pharmaceutical products without the need for reformulation. Hydrogels with high water content and reversible hydrophilicity offer a promising platform for reducing storage temperatures without refrigeration. As a model, poly(N‐isopropylacrylamide) is selected as a basis for creating a potentially low cost and easy‐to‐fabricate hydrogels.
Assembly of Advanced Materials into 3D Functional Structures by Methods Inspired by Origami and Kirigami: A Review
Authors: Ning Xin , Wang Xueju , Zhang Yi , Yu Xinge , Choi Dongwhi , Zheng Ning , Kim Dong Sung , Huang Yonggang , Zhang Yihui , Rogers John A. 
Published: May 2018

AbstractOrigami and kirigami, the ancient techniques for making paper works of art, also provide inspiration for routes to structural platforms in engineering applications, including foldable solar panels, retractable roofs, deployable sunshields, and many others. Recent work demonstrates the utility of the methods of origami/kirigami and conceptually related schemes in cutting, folding, and buckling in the construction of devices for emerging classes of technologies, with examples in mechanical/optical metamaterials, stretchable/conformable electronics, micro/nanoscale biosensors, and large‐amplitude actuators. Specific notable progress is in the deployment of functional materials such as single‐crystal silicon, shape memory polymers, energy‐storage materials, and graphene into elaborate 3D micro and nanoscale architectures. This review highlights some of the most important developments in this field, with a focus on routes to assembly that apply across a range of length scales and with advanced materials of relevance to practical applications.
Crossed PtCoCu Alloy Nanocrystals with High‐Index Facets as Highly Active Catalyst for Methanol Oxidation Reaction
Authors: Xia Zhonghong , Zhang Purui , Feng Guang , Xia Dingguo , Zhang Jiujun 
Published: May 2018

AbstractNanocrystals with high‐index facets are arousing growing attention in terms of rational design of efficient electrocatalysts. Herein, ternary PtCoCu alloys with distinct crossed and dendritic structure are prepared via one‐pot approach simply by tuning the amount of serine. The electrocatalytic performances for methanol oxidation reaction by these PtCoCu alloys are examined. It turns out that the {hk0} high‐index facets‐covered surfaces endow the crossed PtCoCu alloy with 4.2‐fold improvement of specific activity relative to commercial Pt/C and with superior stability. This work provides a facile and feasible route for synthesizing tri‐ or multimetallic alloys for electrocatalytic applications.
Processing‐Dependent Microstructure of AgCl–CsAgCl2 Eutectic Photonic Crystals
Authors: Choi Jaewon , Kulkarni Ashish A. , Hanson Erik , Bacon‐Brown Daniel , Thornton Katsuyo , Braun Paul V. 
Published: May 2018

AbstractDirectional solidification of a eutectic melt allows control over the resultant eutectic microstructure, which in turn impacts both the mechanical and optical properties of the material. These self‐organized phase‐separated eutectic materials can be tuned to have periodicities from tens of micrometers down to nanometers. Furthermore, the two phases possess differences in their refractive index leading to interesting optical properties that can be tailored within the visible to infrared wavelength regime. It is found the binary salt eutectic AgCl–CsAgCl2 system forms a rod microstructure with sample draw rates up to 0.2 mm s−1 which transitions to a lamellar microstructure at draw rates greater than 0.36 mm s−1. Heat‐transfer simulations reveal a draw rate‐dependent direction of motion of the solidification front, which for a range of draw rates requires nucleation of the minority solid phase at the sample wall. Phase‐field modeling indicates that the initial eutectic structure at the sample boundary, either rod or lamellar, dictates the bulk eutectic morphology. These samples contain submicrometer periodicities which coupled with their optical transparency results in them exhibiting draw rate‐dependent near‐IR reflectance peaks consistent with stop bands for 2D hexagonal (rod) and 1D planar (lamellar) photonic crystals.
Tunable Mid‐Infrared Phase‐Change Metasurface
Authors: Dong Weiling , Qiu Yimei , Zhou Xilin , Banas Agnieszka , Banas Krzysztof , Breese Mark B. H. , Cao Tun , Simpson Robert E. 
Published: May 2018

AbstractThe intense light–matter interaction of plasmonic metasurfaces provides an appealing platform for optical sensing. To date, most metasurface sensors are not spectrally tuned. Moreover, they operate in a total reflection mode, which complicates the optical setup. Transmissive tunable filters are therefore desirable. A mid‐infrared (M‐IR) tunable metasurface is described that operates in transmission mode. The resonant frequency of the filter is tuned by nonvolatile phase transitions to the dielectric properties of the chalcogenide material Ge2Sb2Te5. A broad transmittance spectral shift of 500 nm across the M‐IR region is experimentally demonstrated. This shift is in good agreement with finite‐difference time‐domain simulations of the same structure. The design paves the way for on‐chip M‐IR multispectral interferometry and provides a promising approach for compact real‐time M‐IR measurements.
Ultraviolet Light‐Emitting Diode Using Nonpolar AlGaN Core–Shell Nanowire Heterostructures
Authors: Ra Yong‐Ho , Kang San , Lee Cheul‐Ro 
Published: May 2018

AbstractHighly efficient nonpolar AlGaN nanowire ultraviolet light‐emitting diode is developed, wherein core–shell AlGaN multiple quantum well layers are incorporated in the nonpolar active regions. It is confirmed that the core–shell light‐emitting diode (LED) heterostructures are uniformly grown on the nonpolar surfaces of hexagonal GaN nanowires by metalorganic chemical vapor deposition (MOCVD) technique. At room temperature, the nearly defect‐free core–shell AlGaN nanowire heterostructure exhibits high luminescence efficiency (≈74%) in the ultraviolet (UV) wavelength. Compared to conventional uniaxial AlGaN nanowire LED structure, the external quantum efficiency is significantly improved due to dramatically reduced dislocation density and suppressed polarization field, as well as improved carrier injection efficiency. Moreover, the absence of quantum‐confined Stark effect is clearly observed by power‐dependent cathodoluminescence and electroluminescence measurements. This study provides a viable path to realize high‐power UV LEDs, which is critically important for a broad range of applications, including sterilization, disinfection, sensing, and medical diagnostics.
Relaxation of Plasma Carriers in Graphene: An Approach by Frequency‐Dependent Optical Conductivity Measurement
Authors: Choi Wookjin , Nishiyama Hayate , Ogawa Yui , Ueno Yuko , Furukawa Kazuaki , Takeuchi Tomohiro , Tsutsui Yusuke , Sakurai Tsuneaki , Seki Shu 
Published: May 2018

AbstractThe relaxation time and mobility of electrons on graphene are deduced quantitatively by complex permittivity analysis with microwave dielectric loss spectroscopy. Hexagonal graphene sheets with uniform domain sizes from 6 to 30 µm, which target the mean free path of electrons on graphene based on the significantly longer turnover time of microwave probing at gigahertz (GHz) frequencies as compared to the relaxation time of electrons, are employed to determine the factors for carrier relaxation at the intradomain and grain boundaries. The changes in the complex permittivity by carrier injections clearly show an evidence of plasma carriers in graphene. This result validates the plasma carrier model with the restoring force in the GHz regime instead of the free carrier model, which is applied to analyze the optical conductivity over the terahertz (THz) regime. Based on Dirac massless fermions in graphene, the relaxation time of electrons is estimated to be 250–450 fs from the changes in complex permittivity, which are experimentally determined by frequency‐dependent microwave conductivity measurements. The obtained relaxation time shows a positive correlation with the domain size of graphene, implying that the scattering dominantly occurs at the domain boundary.
Surface‐Passivated Cesium Lead Halide Perovskite Quantum Dots: Toward Efficient Light‐Emitting Diodes with an Inverted Sandwich Structure
Authors: Chen Weiwei , Tang Xiaosheng , Wangyang Peihua , Yao Zhiqiang , Zhou Dan , Chen Fenggui , Li Shiqi , Lin Hao , Zeng Fanju , Wu Daofu , Sun Kuan , Li Meng , Huang Yi , Hu Wei , Zang Zhigang , Du Juan 
Published: May 2018

AbstractIn recent years, metal‐halide perovskite quantum dots (QDs) have been broadly applied in optoelectronic fields due to their fascinating characteristics, such as high photoluminescence quantum yields, tunable bandgaps, and low‐cost solution processing. Here, a facile ligand‐exchange strategy is employed for the fabrication of CsPbBr3 QDs capped with di‐dodecyl dimethyl ammonium bromide. It is demonstrated that the treated QDs' film becomes more compact with higher electron mobility and shorter lifetime. Besides, a reduced conduction band minimum value (0.28 eV) of perovskite QDs' film provides an efficient electron injection to them from ZnO nanoparticles. Through using the well‐passivated QDs' film, electroluminescence QD light‐emitting diode (QLED) devices with an indium tin oxide/ZnO/CsPbBr3 QDs/MoO3/4, 4′‐bis(carbazole‐9‐yl)biphenyl/Al inverted sandwich structure are achieved. The as‐prepared QLED device exhibits a maximum current efficiency of 0.62 cd A−1 and an external quantum efficiency of 0.58%, which is nearly nine times higher than that of the device based on unmodified QDs. More importantly, the stability testing results demonstrate that the QLED can be operated for more than 20 min under ambient conditions without any encapsulation. This provides an alternative route for highly efficient perovskite‐based LED with inverted sandwich structures.
Using Simple Fused‐Ring Thieno[2,3‐d]pyrimidine to Construct Orange/Red Ir(III) Complexes: High‐Performance Red Organic Light‐Emitting Diodes with EQEs up to Nearly 28%
Authors: Jiang Bei , Zhao Chenyang , Ning Xiaowen , Zhong Cheng , Ma Dongge , Yang Chuluo 
Published: May 2018

AbstractIn this article, a promising molecular design strategy for obtaining highly efficient orange/red iridium complexes by utilizing simple fused‐ring thieno[2,3‐d]pyrimidine derivatives as the cyclometalated ligands is reported. The introduction of a pyrimidine moiety lowers the lowest unoccupied molecular orbital (LUMO) energy levels and consequently narrows the HOMO–LUMO (HOMO = highest occupied molecular orbital) energy gaps to obtain orange/red emissions. As a result, a series of phosphorescent iridium complexes, namely, PMD‐Ir‐1, PMD‐Ir‐2, PMD‐Ir‐3, and PMD‐Ir‐4, with emission peaks in the range of 578–614 nm are obtained. Notably, phosphorescent organic light‐emitting diodes (PhOLEDs) utilizing PMD‐Ir‐2 and PMD‐Ir‐3 as emitters exhibit orange and red emissions with maximum external quantum efficiencies up to 24.5% and 27.6%, respectively. These results clearly demonstrate that the thieno[2,3‐d]pyrimidine‐based iridium complexes have great potential for fabricating high‐performance orange/red OLEDs.
Metal Hydride‐Based Hydrogen Storage Tank Coupled with an Urban Concept Fuel Cell Vehicle: Off Board Tests
Authors: Capurso Giovanni , Schiavo Benedetto , Jepsen Julian , Lozano Gustavo A. , Metz Oliver , Klassen Thomas , Dornheim Martin 
Published: May 2018

AbstractIn this work, the tests of a hydrogen storage system intended for vehicular applications, using a metal hydride as storage material, are reported. The system is designed to deliver gas to a fuel cell prototype vehicle. The room temperature hydride is an interstitial alloy, which is selected for its capacity to absorb and desorb hydrogen over an appropriate range of temperature and pressure. The static tests aim to assess whether the requirements for hydrogen release are reliably met by the tank setup. Hypothetical on‐road tests have been designed and applied. Dynamic tests allow moving from energy to power density. Solutions are adopted to face the issues of thermal management at higher‐demanding performances. Several cycles have been performed to find the ideal settings to preserve high average and peak gas flow in a realistic situation. The use of a metal hydride, to replace pressurized gas, results in improved performances, including an extended range at lower loading pressures. Decreasing the pressure in the storage system enables the advantageous possibility to reload the tank several times with commercially available cylinders. Possible future enhancements in the reduction of the total weight of the system are also considered.
Transition‐Metal‐Catalyzed Site‐Selective C−H Halogenation Reactions
Authors: Das Riki , Kapur Manmohan 
Published: May 2018

AbstractAryl halides are an indispensably important class of compounds owing to their role as precursors in the synthesis of organometallic reagents and nucleophilic substitution reactions. In addition, with the advent of cross‐coupling chemistry, the importance of aryl halides has increased tremendously, and they are therefore classified as the core building blocks in organic synthesis. With the recent advances in the area of transition‐metal‐catalyzed C−H functionalization, metal‐catalyzed C−H halogenation has emerged as a modern tool in organic synthesis. This focus review highlights the significant developments in the area of directed C−H halogenation reactions, particularly in the last two years.
Recent Developments in the C(sp3)−H Functionalization of 2‐Oxindoles through Radical Reactions
Authors: Chen Wei‐Ting , Wei Wen‐Ting 
Published: May 2018

Abstract3‐Substituted 2‐oxindoles are prevalent in a variety of natural products and bioactive compounds. As such, the synthesis of these molecules is highly desirable. This Focus Review provides a critical overview of recent developments (in particular, reports since 2013) in the C(sp3)−H functionalization of 2‐oxindoles through radical reactions. The main achievements in this field are presented according to the bonds that are formed. Special attention is paid to the reaction mechanisms, and a personal outlook on future developments in this research area is provided.
Designed To React: Terminal Copper Nitrenes and Their Application in Catalytic C−H Aminations
Authors: Moegling Julian , Hoffmann Alexander , Thomas Fabian , Orth Nicole , Liebhäuser Patricia , Herber Ulrich , Rampmaier Robert , Stanek Julia , Fink Gerhard , Ivanović‐Burmazović Ivana , Herres‐Pawlis Sonja 
Published: May 2018

AbstractHeteroscorpionate ligands of the bis(pyrazolyl)methane family have been applied in the stabilisation of terminal copper tosyl nitrenes. These species are highly active intermediates in the copper‐catalysed direct C−H amination and nitrene transfer. Novel perfluoroalkyl‐pyrazolyl‐ and pyridinyl‐containing ligands were synthesized to coordinate to a reactive copper nitrene centre. Four distinct copper tosyl nitrenes were prepared at low temperatures by the reaction with SO2tBuPhINTs and copper(I) acetonitrile complexes. Their stoichiometric reactivity has been elucidated regarding the imination of phosphines and the aziridination of styrenes. The formation and thermal decay of the copper nitrenes were investigated by UV/Vis spectroscopy of the highly coloured species. Additionally, the compounds were studied by cryo‐UHR‐ESI mass spectrometry and DFT calculations. In addition, a mild catalytic procedure has been developed where the copper nitrene precursors enable the C−H amination of cyclohexane and toluene and the aziridination of styrenes.
Underwater polyurethane adhesive with enhanced cohesion by postcrosslinking of glycerol monomethacrylate
Authors: Li Xie , Li Wei , Liu Zhiqing , Wang Xiaolin , Guo Heling , Wang Rongjie , Guo Xuhong , Li Cuihua , Jia Xin 
Published: May 2018

ABSTRACTPolyurethane (PU) has been widely used as a glue in various areas. However, adhesion in the presence of water is greatly impeded and results in most synthetic adhesive failure. In this study, we designed and synthesized a novel PU construction; underwater PU adhesives were created by the incorporation of synthetic glycerol monomethacrylate (GMA). Furthermore, the urethane structure helped the adhesive eliminate the interfacial water barrier through interactions that were stronger than hydrogen bonding, and GMA as a crosslinking agent was used to generate post‐covalent‐crosslinking networks through radical polymerization. This enhanced the cohesion so the diffusion of water molecules could be overcome. Fourier transform infrared spectroscopy, thermogravimetric analysis, underwater adhesion measurements, and tensile tests were used to characterize the chemical and mechanical properties of the as‐obtained adhesive. This led to an adhesive with a better mechanical strength and interfacial adhesion in water, and the results show that the mechanical properties (tensile strength, Young's modulus, and tensile elongation) of the GMA–PU adhesive were higher than those of the pure PU. As for the 4% GMA, the tensile strength was enhanced by 24.3% and the elongation was enhanced by 125.23% over those of the pure PU. This confirmed that the incorporation of GMA into the PU matrix indeed induced increasing cohesion, and the sample's adhesive strength was 21.19 ± 3.9 MPa; this indicated a superior adhesive strength over that of the pure PU. In addition, we can foresee that underwater adhesion will play an important role in prospective surgery and engineering areas. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46579.
Surface modification of polyimide fibers by novel alkaline–solvent hydrolysis to form high‐performance fiber‐reinforced composites
Authors: Yi Xiaolin , Kuang Xiao , Zhang Mengying , Dong Xia , Wu Dezhen , Wang Dujin 
Published: May 2018

ABSTRACTWe modified polyimide (PI) fibers by a novel hydrolysis approach and fabricated PI‐fiber‐reinforced novolac resin (NR) composites with enhanced mechanical properties. We first used an alkaline–solvent mixture containing potassium hydroxide liquor and dimethylacetamide (DMAc) for the surface modification of the PI fibers. The results indicate that the surface roughness and structure of the PI fibers were controlled by the hydrolysis time and the content of DMAc. With the optimized hydrolysis conditions, the tensile modulus of modified PI fibers improved 15% without compromises in the fracture stress, fracture strain, or thermal stability. The interfacial shear strength between the modified PI fibers and NR increased 57%; this indicated a highly enhanced interfacial adhesion. Finally, the tensile and flexural strengths of the composites increased 72 and 53%, respectively. This research provides an effective method for the surface modification of PI fibers and expands their applications for high‐performance composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46595.
Mixing ability examination of three different rotor cross sections and rotor geometry quantification with pressurization coefficient
Authors: Chen Tao , Hao Yuting , Chen Xin , Zhao Haili , Sha Jin , Ma Yulu , Xie Linsheng 
Published: May 2018

ABSTRACTThe geometry of rotor cross section would affect the velocity profile of circumferential flow in continues mixer, which further dominated the mixing ability of rotor. To reveal the relationship between the geometry and mixing ability of rotor cross section, three rotor cross sections with different geometries were chosen, and the POLYFLOW simulations were applied to analyze the velocity profile and the flow stretching. The distribution for three rotors was evaluated both numerically and experimentally with the particle tracking technology. Then, the rotor geometry was quantified with pressurization coefficient S, which is a geometric parameter considering the wedge angle α, width of wing tip e, tip clearance h and the maximum clearance H0 between rotor and chamber wall. The results showed that the mixing ability and S for three rotor cross‐sections would vary with the rotor geometry changing, furthermore, the rotor cross‐section with larger S would have stronger mixing ability. Decreasing α or e, as well as increasing the H0, would induce the increase of S, and further resulting in the improvement of the mixing ability. Rotor geometry quantification with S would intuitionally reveal the relationship between rotor geometry and the mixing ability, and would contribute to the rotor cross‐section design and optimization. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46623.
Preparation of biocidal 4‐ethyl‐4‐(hydroxymethyl)oxazolidin‐2‐one‐basedN‐halamine polysiloxane for impregnation of polypropylene in supercritical CO2
Authors: Chen Yong , He Qingkun , Ren Guoyuan , Feng Chunyan , Li Na , Yu Hao , Han Qiuxia 
Published: May 2018

ABSTRACTA cyclicN‐halamine precursor, 4‐ethyl‐4‐(hydroxymethyl)oxazolidin‐2‐one (EHMO), was synthesized and attached to poly(methylhydrosiloxane) (PMHS) through silane alcoholysis between the OH of EHMO and SiH of PMHS. The alcoholysis product was chlorinated withtert‐butyl hypochlorite to transfer the NH to NCl and obtain an EHMO‐basedN‐halamine polysiloxane. TheN‐halamine polysiloxane was impregnated into inert polypropylene (PP) fibers and formed a 72 nm coating layer using supercritical carbon dioxide (scCO2) as solvent and swelling reagent at 28 MPa and 50 °C for biocidal application. The overall synthetic procedure and the impregnation process were characterized by FTIR, XPS, and SEM, respectively. The N‐halamine polysiloxane layer on PP imparted potent antibacterial abilities against bothStaphylococcus aureusandEscherichia coliwhile pristine ones did not exhibit noticeable killing activities. Stability tests showed that theN‐halamine polysiloxane layer was resistant to washing cycles, storage, and UV irradiation and the rechlorination of lost chlorines was good. The strategy of using CO2‐philic PMHS as carrier polymer and scCO2as working solvent for impregnation presents a general and friendly procedure to functionalize inert substrates without the need of chemical linkage and organic solvent. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 46624.
5,12‐Diacetyl‐5,12‐dihydroquinoxalino[2,3‐b]quinoxalines: Solid‐State Fluorescence, AIE Properties, and Orbital Switching by Substituent Effect
Authors: Miura Youhei , Yoshioka Naoki 
Published: May 2018

AbstractThe compound 5,12‐diacetyl‐5,12‐dihydroquinoxalino[2,3‐b]quinoxaline 1 a and its derivatives were prepared, and their solid‐ and solution‐state spectroscopic properties were studied; 1 a shows stronger fluorescence in solution than in the solid state due to aggregation caused by self‐quenching. Phenyl‐ or alkoxy‐substituted derivatives 1 b–d show solid‐state fluorescence with moderate quantum yields of about Φ=0.12–0.15, although the corresponding values are 0.01–0.07 in solution. The spectroscopic properties of alkoxy‐substituted derivatives were hardly changed compared to 1 a and 1 b, although 1 a and 1 b have similar absorption and fluorescence maxima in solution and in the solid state. DFT calculations indicate that orbital switching occurs between HOMO and HOMO‐1 and HOMO‐2 due to orbital interactions with introduced substituents. Crystal structure analysis revealed that the molecules have bent structures around tertiary nitrogen atoms and form a characteristic dimeric structure.