bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atomic‐Scale Observation of LiFePO4 and LiCoO2 Dissolution Behavior in Aqueous Solutions
Authors: Byeon Pilgyu , Bae Hyung Bin , Chung Hee‐Suk , Lee Sang‐Gil , Kim Jin‐Gyu , Lee Hyeon Jeong , Choi Jang Wook , Chung Sung‐Yoon 
Published: September 2018

AbstractUnderstanding the atomic structure variation at the surface of electrode materials in contact with an electrolyte is an essential step toward achieving better electrochemical performance of rechargeable cells. Different types of water‐based aqueous solutions are suggested as alternative electrolytes to the currently used flammable organic solvents in Li‐ion batteries. However, most research on aqueous rechargeable Li‐ion cells has largely focused on the synthetic processing of materials and resulting electrochemical properties rather than in‐depth atomic‐level observation on the electrode surface where the initial charge transfer and the (de)intercalation reaction take place. By using LiFePO4 and LiCoO2 single crystals, serious P and Co dissolution from LiFePO4 and LiCoO2 into aqueous solutions without any electrochemical cycling is identified. Furthermore, both strong temperature‐dependent behavior of P dissolution in LiFePO4 and very unusual occupancy of Co in the tetrahedral interstices in LiCoO2 are directly demonstrated via atomic‐scale (scanning) transmission electron microscopy. Ab initio density functional theory calculations also reveal that this tetrahedral‐site occupation is stabilized when cation vacancies are simultaneously present in both Li and Co sites. The findings in this work emphasize the significance of direct observation on the atomic structure variation and local stability of the cathode materials.
Tunable Stimuli‐Responsive Color‐Change Properties of Layered Organic Composites
Authors: Takeuchi Machi , Gnanasekaran Karthikeyan , Friedrich Heiner , Imai Hiroaki , Sommerdijk Nico A. J. M. , Oaki Yuya 
Published: September 2018

AbstractStimuli‐responsive properties of soft materials originate from dynamic structure changes. Layered polydiacetylene (PDA) shows color‐change properties with the application of external stimuli, such as thermal and mechanical stresses. Layered organic materials possessing intercalation capabilities and dynamic properties have potentials for tuning their structures and properties by the intercalated guests. A variety of sensing and imaging devices can be developed by control of the stimuli responsivity. Here, the key structures, processes, and mechanisms for tuning the stimuli‐responsive color‐change properties of layered PDA are studied by in situ analyses with heating and cooling. The in situ analyses indicate that heating initiates thermal motion of the alkyl side chains of the PDA main chain in the host layers around 60 °C, regardless of the type of intercalated guests. Further heating induces torsion of the PDA main chain leading to color changes at different temperatures, depending on the types of the intercalated guest. Then, the layered structure is irreversibly deformed with lowering the crystallinity. The results indicate that the stimuli‐responsive color‐change properties are controlled by the rigidity of the layered structures consisting of the host layers and guests. The control strategy based on rigidity tuning can be applied to a variety of soft materials with stimuli responsivity.
An Aqueous Rechargeable Zinc‐Organic Battery with Hybrid Mechanism
Authors: Wan Fang , Zhang Linlin , Wang Xinyu , Bi Songshan , Niu Zhiqiang , Chen Jun 
Published: September 2018

AbstractAqueous zinc‐ion batteries have been considered as potential energy storage devices owing to their high safety and low cost. Traditional zinc‐ion batteries often implement a typical Zn2+ insertion/extraction mechanism. Compared with traditional Zn2+ insertion/extraction mechanism, supercapacitor‐liked dual‐ion mechanism often endow the batteries with higher operating voltage, better rate capability, and longer cycle life. Herein, aqueous Zn/polyaniline batteries are developed, which can combine the Zn2+ insertion/extraction and dual‐ion mechanisms. The Zn/polyaniline batteries deliver excellent electrochemical performance, especially a long cycle life up to 3000 cycles with high‐capacity retention of 92%. This hybrid mechanism provides a promising battery chemistry. Furthermore, Zn/polyaniline batteries can be assembled into quasi‐solid‐state soft‐packaged and cable‐type configurations and display stable electrochemical performance even under different bending states, showing potential applications for flexible electronics.
Alignment‐Free Liquid‐Capsule Pressure Sensor for Cardiovascular Monitoring
Authors: Fan Xiangyu , Huang Yan , Ding Xiaorong , Luo Ningqi , Li Chenglin , Zhao Ni , Chen Shih‐Chi 
Published: September 2018

AbstractWearable pressure sensors enable long‐term real‐time health monitoring in a noninvasive and power‐efficient way; however, the sensors are often required to be precisely applied at the optimal measurement spot, e.g., nearby radial artery, for signal acquisition, causing inconvenience for untrained users or the elders. In this paper, a wearable liquid‐capsule sensor platform embedded with a piezo‐resistive pressure sensor is presented for continuous, accurate, and alignment‐relaxed physiological monitoring, i.e., heart rate (HR) and blood pressure (BP) tracking. The flexible capsule design ensures comfort and good device conformation to any skin regions. For HR and BP measurements, experiments are performed on 12 human subjects. The results show that the capsuled sensor can continuously track: 1) HR with a mean absolute difference (MAD) of 0.88 beats per minute (bpm) and 2) BP with a MAD<3 mmHg for both diastolic and systolic blood pressure. The new liquid‐capsule‐based sensor platform may help to realize an accurate, flexible, robust, and low‐power solution for next‐generation wearable health monitoring devices.
Interface Structure and Evolution of Dinaphthothienothiophene (DNTT) Films on Noble Metal Substrates
Authors: Dreher Maximilian , Bischof Daniel , Widdascheck Felix , Huttner Andrea , Breuer Tobias , Witte Gregor 
Published: September 2018

AbstractDinaphthothienothiophene (DNTT) is a promising new organic semiconductor which combines high charge carrier mobility with chemical robustness. Although the properties of organic electronic devices are largely determined by the interfaces with electrodes, the interface between DNTT and metals is hardly studied so far. Here, the interface structures of DNTT on Ag(111) and multilayers are examined and they are compared with films grown on polycrystalline and (111) surfaces of silver and gold. In the seedlayer regime, two different interface structures formed by exclusively flatlying molecules and a herringbone arrangement are identified for increased coverages. Combining low energy electron diffraction, scanning tunneling microscopy, and X‐ray absorption measurements, precise structure data for both phases are derived and their respective adsorption energies are determined to explain why both phases are formed. On all examined surfaces, DNTT multilayers consist of discrete fibers reflecting a notable dewetting but exhibit different molecular orientations: Molecules are recumbently arranged on the (111) surfaces, but uprightly oriented on polycrystalline surfaces. Complementary work function measurements yield rather similar values for DNTT monolayers on single‐ and polycrystalline metal substrates, while distinct differences are found for thicker films. The results appear important for improved transistor geometries, in particular vertical field‐effect transistors.
Polarization‐Dependent Photocurrent of Black Phosphorus/Rhenium Disulfide Heterojunctions
Authors: Li Xiao‐Kuan , Gao Xiao‐Guang , Su Bao‐Wang , Xin Wei , Huang Kai‐Xuan , Jiang Xiao‐Qiang , Liu Zhi‐Bo , Tian Jian‐Guo 
Published: September 2018

AbstractVan der Waals (vdW) heterojunctions of 2D layered materials possess excellent interface quality without the constraint of lattice mismatch, which enables the application of nanomaterials in electronic and optoelectronic devices. The anisotropy of 2D materials however, also plays an important role in the stacking process of vdW heterojunction. Black phosphorus (BP) and rhenium disulfide (ReS2), as two strong anisotropic 2D materials, have intrinsic in‐plane anisotropic properties that can be used in polarization‐sensitive photoelectric devices. Herein, two types of BP/ReS2 heterojunctions are stacked by controlling their crystal orientation, with the armchair (AC) direction of BP parallel to the b‐axis of ReS2 (ABJ) and zigzag (ZZ) direction of BP parallel to the b‐axis of ReS2 (ZBJ). ABJ exhibits stronger polarization‐dependent photocurrent with a polarized photocurrent ratio of 31, when polarized light is illuminated along the AC and ZZ directions. Our results suggest that this heterojunction has potential application in polarization‐dependent optoelectronic detection.
Hybrid Conducting Composite Films Based on Polypyrrole and Poly(2‐(diethylamino)ethyl methacrylate) Hydrogel Nanoparticles for Electrochemically Controlled Drug Delivery
Authors: Gutiérrez‐Pineda Eduart , Cáceres‐Vélez Paolin Rocio , Rodríguez‐Presa María José , Moya Sergio E. , Gervasi Claudio A. , Amalvy Javier I. 
Published: September 2018

AbstractA 3D conductive hybrid film is fabricated based on poly 2‐(diethylamino) ethyl methacrylate (PDEA) nanoparticles with polypyrrole (PPy) as the conductive component. PDEA nanoparticles are deposited on a gold substrate by drop casting. Then, PPy is electrochemically grown through the hydrogel nanoparticles as a semi‐interpenetrating polymer network. PDEA hydrogel nanoparticles reversibly swell at low pH while PPy liberates H+ in the oxidized state. The oxidation of PPy is used to create an electrostimulated decrease in pH in the PDEA/PPy hybrid film that results in film swelling. The electrochemical properties of the hybrid conductive composite film are studied through cyclic voltammetry and electrochemical impedance spectroscopy. Doxorubicin (Dox) as model drug is encapsulated in the PDEA/PPy hybrid composite film by a pH switch. Drug electroliberation is investigated at different applied potentials from −0.65 to +0.65 V. The amount of Dox released shows a dependence on the applied potential and the duration of the electrical stimuli. The (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) tetrazolium reduction assay is conducted to evaluate the impact of the electrocontrolled release of Dox on the proliferation of the A549 cell line, showing a decrease in cell viability, proportional to the applied potential and its duration.
Largely Lowered Transition Temperature of a VO2/Carbon Hybrid Phase Change Material with High Thermal Emissivity Switching Ability and Near Infrared Regulations
Authors: Wang Shancheng , Liu Guowei , Hu Peng , Zhou Yang , Ke Yujie , Li Chuanchang , Chen Jian , Cao Tun , Long Yi 
Published: September 2018

AbstractVanadium oxide (VO2) as a phase changing material possesses abrupt infrared (IR) transmission and thermal emissivity changing during the metal–insulator transition across transition temperature (τc) of 68 °C. However, the high τc, moderate IR transmission and emissivity regulating ability limits its applications in various fields. A VO2/carbon hybrid phase change material fabricated via homemade plasma enhanced chemical vapor deposition is reported. The material shows a best reported thermal emissivity contrast (0.44) among the experimental values, a largely lowered τc (45 °C), promising a near IR‐regulation ability with enhanced photothermal effect in smart windows applications. The theoretical calculation results proved that the improvement of emissivity contrast is due to the hybridization of carbon. This work provides a new approach to synthesize VO2 hybrid materials, which have wide applications in camouflage, sensing, and smart windows.
Exploring Indium‐Based Ternary Thiospinel as Conceivable High‐Potential Air‐Cathode for Rechargeable Zn–Air Batteries
Authors: Fu Gengtao , Wang Jie , Chen Yifan , Liu Yu , Tang Yawen , Goodenough John B. , Lee Jong‐Min 
Published: September 2018

AbstractReversible oxygen reactions in Zn–air batteries require cost‐effective and highly‐active bifunctional electrocatalysts to substitute traditional noble‐metal based catalysts. Herein, a new and promising electrocatalytic material, ternary CoIn2S4 thiospinel, is demonstrated for effectively catalyzing oxygen reduction and oxygen evolution reactions (ORR and OER) with S‐doped reduced graphene oxide (S‐rGO) as an electronic conductor. Compared with Co9S8/S‐rGO (without In doping), the newly developed CoIn2S4/S‐rGO reveals superior electrocatalytic properties for the ORR (half‐wave potential of 0.83 V) and OER (overpotential of 0.37 V at 10 mA cm−2), demonstrating that the introduction of In can promote the reversible oxygen electrode reactions of CoIn2S4. The superior experimentally‐observed electrocatalytic properties are corroborated via density function theory investigations. Meanwhile, the synergistic improvements in the bifunctional activities resulting from the combination of CoIn2S4 and S‐rGO are also confirmed. As a proof of concept, home‐made Zn–air cells are assembled with CoIn2S4/S‐rGO as an air‐cathode. The developed Zn–air cells exhibit a high peak power density (133 mW cm−2) with an energy density of 951 Wh kgZn−1 and robust cycling stability over 150 cycles for 50 h, exceeding of those commercial Pt/C+RuO2 which highlights the practical viability of CoIn2S4/S‐rGO for rechargeable Zn–air batteries.
The two cultures of health and social care might perhaps be brought together by assets
Authors: Rahman Shibley 
Published: September 2018

AbstractArguably, there are two sides to the frailty “coin,” with only one culture dominated by deficits. Certainly, as cells age, they develop deficits as a result of the accumulation of unrepaired cellular and molecular damage; however, the factors that make people well or healthy are important in defending against deficits and building up resilience, and need to be routinely discussed with patients. I argue that all health and social care professionals should feel confident in exploring assets or more “positive aspects” of living, and this common language could even drive integration between person‐centered services.
Chiral Bifunctional Ferrocenylphosphine‐Catalyzed Enantioselective Allylic Alkylation of Morita−Baylis−Hillman Carbonates with Pyrazolin‐5‐ones
Authors: Luo Wenjun , Song Dingguo , Fang Lu , Nian Sanfei , Hou Huacui , Ling Fei , Zhong Weihui 
Published: September 2018

AbstractA chiral bifunctional ferrocenylphosphine catalyzed asymmetric allylic alkylation of Morita−Baylis−Hillman (MBH) carbonates with pyrazolin‐5‐ones was developed. The reaction afforded the desired pyrazolone derivatives in moderate to good yields (up to 80%), and with high enantioselectivities (up to 98% ee).
Phase‐Retrieval Algebraic Solution Based on Window Modulation
Authors: Huang Jianhui , Jin Huiliang , Ye Qian , Meng Guoxiang 
Published: September 2018

AbstractPhase retrieval is to recover the object amplitude and phase from the diffraction patterns. Here, an algebraic method is presented to solve the phase retrieval problems of arbitrary 2D complex‐valued objects, without the requirements of numerous iterations, object prior knowledge, and precise experimental setups. The key step is to extract the far‐field phase from the diffraction patterns. It is demonstrated by rigorous theoretical derivation that three window‐shaped modulations are sufficient to establish a system of linear equations related to the far‐field phase, from which the far‐field phase is solved approximately with only algebraic calculations. Then, an efficient iteration scheme is designed to optimize the direct approximate solution. After a few iterations, the direct solution is improved quickly and very close to the exact solution. With the advantages of high speed and high accuracy to general phase retrieval problems, the proposed algebraic method may be helpful to the Fourier imaging systems in which interferometric techniques are not applicable.
Magnetite Fe3O4 Has no Intrinsic Peroxidase Activity, and Is Probably not Involved in Alzheimer's Oxidative Stress
Authors: Gumpelmayer Michelle , Nguyen Michel , Molnár Gábor , Bousseksou Azzedine , Meunier Bernard , Robert Anne 
Published: September 2018

AbstractDespite stated in some highly cited articles, magnetite is devoided of peroxidase activity. In fact, this very stable mixed valence FeIIO⋅FeIII2O3 complex is not catalytically competent to oxidize standard peroxidase substrates, especially at the biologically relevant pH value of 7.4. In addition, magnetite whose deleterious redox activity has been suspected in Alzheimer's disease brain damages, does not significantly interact with amyloid peptide Aβ in vitro, and is not able to induce, either in the presence or absence of Aβ, the reductive activation of dioxygen, the first step of an oxidative stress. In fact, this highly insoluble mineral iron derivative is probably not involved in the oxidative damage of brain neurons of patients with AD.
A Stereodynamic Redox‐Interconversion Network of Vicinal Tertiary and Quaternary Carbon Stereocenters in Hydroquinone–Quinone Hybrid Dihydrobenzofurans
Authors: Storch Golo , Kim Byoungmoo , Mercado Brandon Q. , Miller Scott J. 
Published: September 2018

AbstractReversible redox processes involving hydroquinones and quinones are ubiquitous in biological reaction networks, materials science, and catalysis. While extensively studied in intermolecular settings, less is known about intramolecular scenarios. Herein, we report hydroquinone–quinone hybrid molecules that form two‐stereocenter dihydrobenzofurans via intramolecular cyclization under thermodynamic control. A π‐methylhistidine peptide‐catalyzed kinetic resolution allowed us to study the stereodynamic behavior of enantio‐ and diastereo‐enriched dihydrofurans. In the course of this study, it was revealed that a reversible intramolecular redox‐interconversion network connects all four possible stereoisomers via inversion of a quaternary carbon stereocenter without achiral intermediates. As a result, these findings on hydroquinone‐quinone hybrid molecules provide insights into potential natural origin and synthetic access of the common dihydrobenzofuran motif.
Total Syntheses of Bisdehydroneostemoninine and Bisdehydrostemoninine by Catalytic Carbonylative Spirolactonization
Authors: Ma Kaiqing , Yin Xianglin , Dai Mingji 
Published: September 2018

AbstractThe first total syntheses of the stemona alkaloids bisdehydroneostemoninine and bisdehydrostemoninine in racemic forms have been achieved. The synthetic strategy features a novel palladium‐catalyzed carbonylative spirolactonization of a hydroxycyclopropanol to rapidly construct the oxaspirolactone moiety. It also features a Lewis acid promoted tandem Friedel–Crafts cyclization and lactonization to form the 5‐7‐5 tricyclic core of the target stemona alkaloids.
Palladium/Graphitic Carbon Nitride (g‐C3N4) Stabilized Emulsion Microreactor as a Store for Hydrogen from Ammonia Borane for Use in Alkene Hydrogenation
Authors: Han Chenhui , Meng Peng , Waclawik Eric R. , Zhang Chao , Li Xin‐Hao , Yang Hengquan , Antonietti Markus , Xu Jingsan 
Published: September 2018

AbstractDirect hydrogenation of C=C double bonds is a basic transformation in organic chemistry which is vanishing from simple practice because of the need for pressurized hydrogen. Ammonia borane (AB) has emerged as a hydrogen source through its safety and high hydrogen content. However, in conventional systems the hydrogen liberated from the high‐cost AB cannot be fully utilized. Herein, we develop a novel Pd/g‐C3N4stabilized Pickering emulsion microreactor, in which alkenes are hydrogenated in the oil phase with hydrogen originating from AB in the water phase, catalysed by the Pd nanoparticles at the interfaces. This approach is advantageous for more economical hydrogen utilization over conventional systems. The emulsion microreactor can be applied to a range of alkene substrates, with the conversion rates achieving >95 % by a simple modification.
Simple Alkaline‐Earth Metal Catalysts for Effective Alkene Hydrogenation
Authors: Bauer Heiko , Alonso Mercedes , Fischer Christian , Rösch Bastian , Elsen Holger , Harder Sjoerd 
Published: September 2018

AbstractAlkaline earth metal amides (AeN′′2: Ae=Ca, Sr, Ba, N′′=N(SiMe3)2) catalyze alkene hydrogenation (80–120 °C, 1–6 bar H2, 1–10 mol % cat.), with the activity increasing with metal size. Various activated C=C bonds (styrene, p‐MeO‐styrene, α‐Me‐styrene, Ph2C=CH2, trans‐stilbene, cyclohexadiene, 1‐Ph‐cyclohexene), semi‐activated C=C bonds (Me3SiCH=CH2, norbornadiene), or non‐activated (isolated) C=C bonds (norbornene, 4‐vinylcyclohexene, 1‐hexene) could be reduced. The results show that neutral Ca or Ba catalysts are active in the challenging hydrogenation of isolated double bonds. For activated alkenes (e.g. styrene), polymerization is fully suppressed due to fast protonation of the highly reactive benzyl intermediate by N′′H (formed in the catalyst initiation). Using cyclohexadiene as the H source, the first Ae metal catalyzed H‐transfer hydrogenation is reported. DFT calculations on styrene hydrogenation using CaN′′2 show that styrene oligomerization competes with styrene hydrogenation. Calculations also show that protonation of the benzylcalcium intermediate with N′′H is a low‐energy escape route, thus avoiding oligomerization.
Tuning Intramolecular Förster Resonance Energy Transfer and Activating Intramolecular Singlet Fission
Authors: Lavarda Giulia , Zirzlmeier Johannes , Gruber Marco , Rami Parisa R. , Tykwinski Rik R. , Torres Tomás , Guldi Dirk M. 
Published: September 2018

AbstractThe synergy of panchromatic absorption throughout most of the visible range of the solar spectrum and intramolecular singlet fission (SF) has been realized in a series of conjugates featuring different light‐harvesting subphthalocyanines (SubPcs) and an energy accepting pentacene dimer (Pnc2). At the focal point was a modular SubPc approach, which was based on decorating the SubPc core with different peripheral substituents to tailor and fine‐tune their optical properties. Transient absorption measurements assisted in corroborating that the SubPcs act as energy‐transfer antennas by means of unidirectional and quantitative intramolecular Förster resonance energy transfer (FRET) to the Pnc2, where an intramolecular SF affords triplet quantum yields reaching unity.
Mechanical properties of linear low‐density polyethylene fire‐retarded with melamine polyphosphate
Authors: Zaghloul Moustafa Mahmoud Yousry Mahmoud 
Published: September 2018

ABSTRACTThe ecologically friendly flame retardant melamine polyphosphate (MPP) was prepared and incorporated into linear low‐density polyethylene (LLDPE). The impacts of this halogen‐free flame retardant on the mechanical characteristics of LLDPE were investigated in this research. The flame‐retardant properties were evaluated, and the mechanical properties, including flexural, tensile, compressive, fracture toughness, and shear behaviors, were tested. The weight fraction of the filler material ranges from 5% to 30%. The influence of filler weight content of the produced composites was evaluated by means of a universal testing machine in order to identify their behavior. The flammability of composites was highly improved with the addition of MPP. It was observed that the Young's modulus and flexural modulus increased almost linearly; similarly, the tensile fracture strength and tensile yield strength increased with the increase in MPP weight fraction. The tensile elongation at break decreased sharply between zero and 10% weight fraction, followed by a slight decrease up to 30% weight fraction. The flexural strength peaked with the increase in MPP weight fraction. The compressive strength and shear strength of the specimens were directly proportional to MPP content up to 15% and 30%, respectively. The novelty in the optimization of MPP content as well as the preparation method reveal a wide range of applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 134, 46770