bluuebunny/crossref_metadata_2025 huggingface dataset:
A new family of cation-disordered Zn(Cu)–Si–P compounds as high-performance anodes for next-generation Li-ion batteries
Authors: Li Wenwu , Li Xinwei , Liao Jun , Zhao Bote , Zhang Lei , Huang Le , Liu Guoping , Guo Zaiping , Liu Meilin
Published: May 2019

Cation-disordered Zn(Cu)–Si–P family materials demonstrate better Li-storage performance than the cation-ordered ZnSiP2 phase due largely to faster electronic and ionic conductivity and better tolerance to volume change during cycling, as confirmed by DFT calculations and experimental measurements.
Modulation of the gut microbiota by a galactooligosaccharide protects against heavy metal lead accumulation in mice
Authors: Zhai Qixiao , Wang Jing , Cen Shi , Zhao Jianxin , Zhang Hao , Tian Fengwei , Chen Wei
Published: May 2019

GOS prevents Pb accumulation by modulating gut microbiota.
Visible light promoted PANI@Au:CuO catalyzed sequential amination, azidation and annulation for the preparation of 2-arylbenzimidazoles
Authors: Chopra Radhika , Kumar Manoj , Neelam Neelam , Bhalla Vandana
Published: May 2019

A protocol describing PANI@Au:CuO photocatalyzed sequential amination/azidation/annulation reactions to prepare 2-aryl benzimidazole derivatives has been developed.
Femtosecond laser-induced breakdown spectroscopy studies for the identification of plastics
Authors: Junjuri Rajendhar , Gundawar Manoj Kumar
Published: May 2019

We report the identification of five extensively used postconsumer plastics using the femtosecond laser-induced breakdown spectroscopy (fs-LIBS) technique.
Chloride carbodiimide K12Pb51(CN2)30Cl54 with an unprecedented 45 Å unit cell axis and a large birefringence
Authors: Meng Xianghe , Liang Fei , Yin Wenlong , Lin Zheshuai , Xia Mingjun
Published: May 2019

K12Pb51(CN2)30Cl54 exhibits a giant birefringence of 0.094 at 1064 nm and a large cell axis due to the rotation of Pb2+ cations.
Photophysics of proton transfer in hydrazides: a combined theoretical and experimental analysis towards OLED device application
Authors: Mohan Makesh , Satyanarayan M. N. , Trivedi Darshak R.
Published: May 2019

Effect of conjugation to support ESIPT with impossible double proton transfer in structurally favored species.
Actinobacteria associated with stingless bees biosynthesize bioactive polyketides against bacterial pathogens
Authors: Rodríguez-Hernández Diego , Melo Weilan G. P. , Menegatti Carla , Lourenzon Vitor B. , do Nascimento Fábio S. , Pupo Mônica T.
Published: May 2019

Strong activity against the bacteria Paenibacillus larvae ATCC9545, the causative agent of the American Foulbrood disease of honey bees.
Niobium uptake by a [P8W48O184]40−macrocyclic polyanion
Authors: Shmakova Alexandra A. , Volchek Victoria V. , Yanshole Vadim , Kompankov Nikolay B. , Martin Nicolas P. , Nyman May , Abramov Pavel A. , Sokolov Maxim N.
Published: May 2019

Incorporation of Nb into the [P8W48O184]40−anionic macrocyclic cavitand leads to formation of new Nb–W POMs. Inclusion of up to five {NbO(H2O)}3+groups was observed. Solution speciation of the Nb-encapsulating macrocycles was studied by HPLC-ICP-AES and SAXS.
An efficient hydrophobic modification of TS-1 and its application in the epoxidation of propylene
Authors: Wang Baohe , Han Huanhuan , Ge Baomin , Ma Jing , Zhu Jing , Chen Shuang
Published: May 2019

Hydrophobic TS-1 was synthesized through resole resin precursor modification. Hydrophobic TS-1 can avoid by-product generation.
1T/2H multi-phase MoS2 heterostructures: synthesis, characterization and thermal catalysis decomposition of dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate
Authors: Hu Lishuang , Liu Yang , Hu Shuangqi , Wang Yanping
Published: May 2019

Dependence of ln(β/Tp2) on 1/Tp for TKX-50 and mixtures with 10 wt% 2H-MoS2 and 1T/2H-MoS2.
Electrical and geometrical tuning of MoS2 field effect transistors via direct nanopatterning
Authors: Urbanos Fernando J. , Black A. , Bernardo-Gavito Ramón , Vázquez de Parga A. L. , Miranda Rodolfo , Granados D.
Published: May 2019

We present a direct nano-patterning route for modifying the conduction channel geometry and optoelectronic properties of MoS2 based FETs.
Catalytic hydrogen evolution reaction on “metal-free” graphene: key role of metallic impurities
Authors: Wang Lu , Sofer Zdeněk , Pumera Martin
Published: May 2019

Molecular hydrogen is widely considered as a potential carbon-free and renewable energy carrier for a sustainable energy strategy. Carbon nanotubes are widely promoted as metal-free catalysts – however, we show that the metallic impurities drive hydrogen production.
Fluorescent gels: a review of synthesis, properties, applications and challenges
Authors: Li Yuqiong , Young David James , Loh Xian Jun
Published: May 2019

Soft material gels are important biomaterials for tissue engineering and biomedicine. Fluorescent gels possess the additional property of being light emitting, with advanced applications in sensing, bioimaging, and electrofluorochromic devices.
A diphenylamino-substituted cationic cyclometalated Ir(iii) complex: its aggregation-induced phosphorescent emission and oxygen sensing properties
Authors: Wang Lei , Gao Zhanming , Liu Chun , Jin Xin
Published: May 2019

A new diphenylamino (DPA)-substituted cationic cyclometalated Ir(iii) complex, Ir2, demonstrates aggregation-induced phosphorescent emission (AIPE) and exhibits higher sensitivity to O2 in an EC film than non-DPA-modified Ir1.
The formation of yolk–shell structured NiO nanospheres with enhanced lithium storage capacity
Authors: Wang Jian , Su Panpan , Zhang Jing , Wang Fangfang , Chen Yali , Liu Hao , Liu Jian
Published: May 2019

Yolk–shell structured NiO nanospheres were successfully fabricated and showed excellent performance as an anode for lithium-ion batteries.
Green synthesis characterization and antimicrobial activity againstStaphylococcus aureusof silver nanoparticles using extracts of neem, onion and tomato
Authors: Chand Kishore , Abro M. Ishaque , Aftab Umair , Shah Ahmer Hussain , Lakhan Muhammad Nazim , Cao Dianxue , Mehdi Ghazanfar , Ali Mohamed Abdalla Mohamed
Published: May 2019

The silver nanoparticles were synthesized from the neem leaves, onions, and tomato extracts, and the antibacterial activity of the particles was studied.
Mixing thermodynamics and electronic structure of the Pt1−xNix(0 ≤x≤ 1) bimetallic alloy
Authors: Botha Louise M. , Santos-Carballal David , Terranova Umberto , Quesne Matthew G. , Ungerer Marietjie J. , van Sittert Cornelia G. C. E. , de Leeuw Nora H.
Published: May 2019

Density functional theory simulations complemented by force-field based calculations show that the bimetallic Pt0.5Ni0.5equilibrium composition is highly ordered at room conditions.
Correction: A highly sensitive and selective fluorescent probe for quantitative detection of Al3+ in food, water, and living cells
Authors: Jiang Qian , Li Mingxin , Song Jie , Yang Yiqin , Xu Xu , Xu Haijun , Wang Shifa
Published: May 2019

Correction for ‘A highly sensitive and selective fluorescent probe for quantitative detection of Al3+ in food, water, and living cells’ by Qian Jiang et al., RSC Adv., 2019, 9, 10414–10419.
Sacrificial oxidation of a self-metal source for the rapid growth of metal oxides on quantum dots towards improving photostability
Authors: Huang Lu , Li Zhichun , Zhang Congyang , Kong Long , Wang Bo , Huang Shouqiang , Sharma Vaishali , Ma Houyu , Yuan Qingchen , Liu Yue , Shen Guoqing , Wu Kaifeng , Li Liang
Published: May 2019

A sacrificial oxidation of a self-metal source strategy to rapidly anchor metal oxides on individual QD surfaces for improved photostability was reported.
De novo synthesis, structural assignment and biological evaluation of pseudopaline, a metallophore produced by Pseudomonas aeruginosa
Authors: Zhang Jian , Zhao Tianhu , Yang Rongwen , Siridechakorn Ittipon , Wang Sanshan , Guo Qianqian , Bai Yingjie , Shen Hong C. , Lei Xiaoguang
Published: May 2019

The first total synthesis and isolation of pseudopaline was reported, which allows determination and confirmation of the absolute configuration of the natural product.
Dual resonance energy transfer in triple-component polymer dots to enhance electrochemiluminescence for highly sensitive bioanalysis
Authors: Wang Ningning , Wang Ziyu , Chen Lizhen , Chen Weiwei , Quan Yiwu , Cheng Yixiang , Ju Huangxian
Published: May 2019

A dual intramolecular electrochemiluminescence resonance energy transfer process is proposed with triple-component Pdots to enhance ECL emission, which greatly improves the ECL efficiency and can be used for sensitive and specific visual quantification of different targets.
Machine learning and molecular descriptors enable rational solvent selection in asymmetric catalysis
Authors: Amar Yehia , Schweidtmann Artur M. , Deutsch Paul , Cao Liwei , Lapkin Alexei
Published: May 2019

Rational solvent selection remains a significant challenge in process development.
Single-cluster Au as an usher for deeply cyclable Li metal anodes
Authors: Yang Tingzhou , Qian Tao , Shen Xiaowei , Wang Mengfan , Liu Sisi , Zhong Jun , Yan Chenglin , Rosei Federico
Published: May 2019

Single-cluster Au uniformly dispersed on a substrate as a model to control directed Li deposition and suppress Li dendrite growth.
A three-dimensional multilevel nanoporous NiCoO2/Ni hybrid for highly reversible electrochemical energy storage
Authors: Liu Binbin , Hou Jiagang , Zhang Tingting , Xu Caixia , Liu Hong
Published: May 2019

A three dimensional (3D) multilevel nanoporous NiCoO2 cathode with a conductive Ni matrix is made by a one-step dealloying strategy. Benefiting from the 3D interlinking configurations for ion and electron transport, and the abundant active sites, the as-made NiCoO2/Ni cathode demonstrates superior energy storage performances.
Metallic NiSe2nanoarrays towards ultralong life and fast Li2S oxidation kinetics of Li–S batteries
Authors: Wang Maoxu , Fan Lishuang , Wu Xian , Qiu Yue , Guan Bin , Wang Yan , Zhang Naiqing , Sun Kening
Published: May 2019

The complex solid–liquid–solid phase transition in Li–S batteries, the serious shuttle effect of soluble polysulfides, sluggish polysulfide conversion kinetics and the low conductive nature of Li2S cause a high decomposition barrier, inevitably limiting the development of advanced Li–S batteries.
Ferrocene-based metal–organic framework nanosheets loaded with palladium as a super-high active hydrogenation catalyst
Authors: Deng Zheng , Yu Haojie , Wang Li , Liu Jiyang , Shea Kenneth J.
Published: May 2019

Ultra-thin Zr-Fc MOF nanosheets were prepared as highly efficient heterogeneous catalysts for the in situ reduction of Pd2+ into Pd nanoparticles.
Hierarchical chemomechanical encoding of multi-responsive hydrogel actuators via 3D printing
Authors: Odent Jérémy , Vanderstappen Sophie , Toncheva Antoniya , Pichon Enzo , Wallin Thomas J. , Wang Kaiyang , Shepherd Robert F. , Dubois Philippe , Raquez Jean-Marie
Published: May 2019

A family of multi-responsive hydrogel-based actuators capable of rapid and controllable motion in response to any immediate environmental change is herein demonstrated towards the 3D-printing of functionally graded structures that are encoded with anisotropic swelling behavior.
Design of sepiolite-supported ionogel-embedded composite membranes without proton carrier wastage for wide-temperature-range operation of proton exchange membrane fuel cells
Authors: Zhang Xiaoxiao , Fu Xudong , Yang Shoukun , Zhang Yuanfang , Zhang Rong , Hu Shengfei , Bao Xujin , Zhao Feng , Li Xiao , Liu Qingting
Published: May 2019

An ionogel incorporated into poly(2,5-benzimidazole) membranes was designed for the applications of PEMFCs in a wide temperature range.
Nanoporous Cu@Cu2O hybrid arrays enable photo-assisted supercapacitor with enhanced capacities
Authors: An Cuihua , Wang Zhifeng , Xi Wei , Wang Kai , Liu Xizheng , Ding Yi
Published: May 2019

We design and fabricate a photo-assisted rechargeable supercapacitor by integrating photo-working electrode together, a nanoporous Cu@Cu2O hybrid arrays, which obviously increase the charge capacity.
The multi-yolk/shell structure of FeP@foam-like graphenic scaffolds: strong P–C bonds and electrolyte- and binder-optimization boost potassium storage
Authors: Tan Qiwei , Zhao Wang , Han Kun , Li Ping , Wang Wei (Alex) , He Donglin , Liu Zhiwei , Yu Qiyao , Qin Mingli , Qu Xuanhui
Published: May 2019

We fabricate novel FeP@Foam-like graphenic scaffolds (termed as FeP@FGCS)viaa facile pyrolysis-blowing strategy toward fast and durable potassium storage.
Self-assembling injectable peptide hydrogels for emerging treatment of ischemic stroke
Authors: Hong Andrew , Aguilar Marie-Isabel , Del Borgo Mark P. , Sobey Christopher G. , Broughton Brad R. S. , Forsythe John S.
Published: May 2019

Ischaemic stroke remains one of the leading causes of death and disability worldwide, without any long-term effective treatments targeted at regeneration. This has led to developments of novel, biomaterial-based strategies using self-assembling peptide hydrogels.
An electrospun fibrous platform for visualizing the critical pH point inducing tooth demineralization
Authors: Niu Jingjing , Guo Jia , Ding Ruolin , Li Xiaoling , Li Yuqing , Xiao Dan , Zhou Cuisong
Published: May 2019

The BCG–PS/PVP electrospun fibrous membrane can rapidly, sensitively and conveniently sense the critical pH point of 5.5 of dental caries.
A polydopamine-coated LAPONITE®-stabilized iron oxide nanoplatform for targeted multimodal imaging-guided photothermal cancer therapy
Authors: Liu Mengxue , Zhang Jiulong , Li Xin , Cai Chao , Cao Xueyan , Shi Xiangyang , Guo Rui
Published: May 2019

A novel targeted theranostic nanoplatform (LAP–Fe3O4@PDA–PEG–PBA) is constructed for magnetic resonance and photoacoustic imaging-guided photothermal therapy of cancer cells overexpressing sialic acid.
Photocrosslinked acemannan-based 3D matrices for in vitro cell culture
Authors: Silva Simone S. , Soares da Costa Diana , Reis Rui L.
Published: May 2019

Photocrosslinking on acemannan is proposed as a green approach for the production of high added-value acemannan structures, enabling its biomedical exploitation.
Improved neural differentiation of stem cells mediated by magnetic nanoparticle-based biophysical stimulation
Authors: Dai Ran , Hang Yingjie , Liu Qi , Zhang Sixuan , Wang Lei , Pan Yue , Chen Hong
Published: May 2019

Stem cell therapy shows great potential in the treatment of neurodegenerative diseases, in which efficient neural differentiation of stem cells is still challenging.
Protein corona of magnetic PEI/siRNA complex under the influence of a magnetic field improves transfection efficiencyviacomplement and coagulation cascades
Authors: Jiang Peipei , Zhu Yue , Kang Ke , Luo Bin , He Jing , Wu Yao
Published: May 2019

Magnetic fields enhance the silencing efficiencyviathe alteration of protein corona adsorbed on magnetic PEI/siRNA complex.
Synthesis of novel nonlinear optical chromophores with enhanced electro-optic activity by introducing suitable isolation groups into the donor and bridge
Authors: Liu Fenggang , Chen Shujie , Mo Songmin , Qin Gangzhi , Yu Canwen , Zhang Weijun , Shi Wen-Jing , Chen Peiling , Xu Huajun , Fu Mingkai
Published: May 2019

Four nonlinear optical chromophores A–D functionalized with different isolation groups on both the donor and bridge sections of the chromophores have been synthesized and systematically investigated.
Simply planarizing nonfused perylene diimide based acceptors toward promising non-fullerene solar cells
Authors: Bian Gao-Feng , Zhao Feng , Lau Tsz-Ki , Sheng Chun-Qi , Lu Xinhui , Du Hui , Zhang Cheng , Qu Zhi-Rong , Chen Hongzheng , Wan Jun-Hua
Published: May 2019

The pyrene core and significantly reduced intramolecular steric hindrance endow a nonfused PDI-tetramer with moderate planarity and good self-assembly properties.
Lipid-dependent Akt-ivity: where, when, and how
Authors: Siess Katharina M. , Leonard Thomas A.
Published: May 2019

Akt is an essential protein kinase activated downstream of phosphoinositide 3-kinase and frequently hyperactivated in cancer. Canonically, Akt is activated by phosphoinositide-dependent kinase 1 and mechanistic target of rapamycin complex 2, which phosphorylate it on two regulatory residues in its kinase domain upon targeting of Akt to the plasma membrane by PI(3,4,5)P3. Recent evidence, however, has shown that, in addition to phosphorylation, Akt activity is allosterically coupled to the engagement of PI(3,4,5)P3 or PI(3,4)P2 in cellular membranes. Furthermore, the active membrane-bound conformation of Akt is protected from dephosphorylation, and Akt inactivation by phosphatases is rate-limited by its dissociation. Thus, Akt activity is restricted to membranes containing either PI(3,4,5)P3 or PI(3,4)P2. While PI(3,4,5)P3 has long been associated with signaling at the plasma membrane, PI(3,4)P2 is gaining increasing traction as a signaling lipid and has been implicated in controlling Akt activity throughout the endomembrane system. This has clear implications for the phosphorylation of both freely diffusible substrates and those localized to discrete subcellular compartments.
The Utility of High-Resolution Pharyngeal Manometry in Dysphagia Treatment
Authors: Davidson Kate (Humphries) , O'Rourke Ashli K.
Published: May 2019

Purpose

High-resolution pharyngeal manometry (HRPM) is an emerging technology that shows promise as both an adjuvant diagnostic and therapeutic tool in oropharyngeal dysphagia management. Advances in manometric technology, including increased number of sensors and topographical pressure plots, enhance the biofeedback potential for the pharynx. This clinical focus article serves as an overview of the utility of HRPM in dysphagia treatment.

Conclusion

HRPM-facilitated biofeedback aids the patient in the correct implementation of clinical recommendations and also provides the clinician an assessment of the effectiveness and accuracy of those targeted interventions. Topographic pressure plots provide intuitive feedback, allow easier swallow-to-swallow comparisons, and produce visually color-coded pressure information for the patient and clinician in real time. Paired with existing, evidence-based interventions, HRPM biofeedback may facilitate maneuver and strategy planning, exercise training and monitoring, temporal coordination, upper esophageal segment relaxation and duration, swallow mapping (topographic pattern recognition and approximation), fatigue monitoring, dose planning, adherence tracking, and efficacy assessment of selected interventions. Although competency training is needed to effectively utilize HRPM, there are growing opportunities for the speech-language pathologist to acquire and implement this technology for the benefit of patients.
Power of looking together: an analysis of social facilitation by Agent's mutual gaze
Authors: Toyono Takuya , Osawa Hirotaka
Published: May 2019

The authors investigated the effect of gaze tracking of humans by an agent. Psychological studies have shown that the presence of others facilitates task with implying partnership. This effect also occurs if the presence of others is replaced with a robot. Furthermore, the previous research showed that being touched by a robot motivates a person. However, direct contact such as the touch of a robot has a risk of disturbing human work. The authors used gaze tracking for social facilitation because gaze tracking can also facilitate human efforts and implemented a social facilitation robot agent by using gaze tracking. The agent projects its face on a surface to show quickly changing expressions, which is difficult to achieve with ordinary robots. The agent can also express gaze tracking by implementing eye trackers. The authors prepared three conditions with monotonous tasks to compare the effects of gaze tracking: the agent gazes at the instructed point moves its gaze randomly and traces the gaze point of a participant. The results showed that the participants’ motivation increased if the agent is tracking gazed point by a human, even though there are no differences between the achievement scores of the task and the continuation time.
Modified steady‐state modelling of brushless doubly‐fed induction generator taking core loss components into account
Authors: Yousefian Mahmoud , Zarchi Hossein Abootorabi , Gorginpour Hamed
Published: May 2019

Brushless doubly‐fed induction machine (BDFIM) has recently gained considerable research interests due to its promising features when incorporated as wind generator or variable speed drive. The BDFIM has two three‐phase stator windings with different pole‐pair numbers and excitation frequencies. The performance of the machine is based on the magnetic cross‐coupling of rotating fields produced by the stator windings through a special squirrel cage rotor. Contrary to the conventional induction machine (IM), the rotor slip and frequency are high throughout the operating speed range. Hence, the rotor core loss cannot be ignored in the steady‐state analysis. Although the core loss components have much more study of BDFIM. In this study, analytical expressions are individually derived for a number of core loss components caused by the complicated nature than those of an IM, the precise calculation of these components is important especially on the efficiency each stator winding field. Then, the modified steady‐state electric equivalent model is developed by considering the components. The experiments and finite element analysis based on a 3kW prototype BDFIM verify the accuracy of the proposed model.
High‐performance differentially fed coupled‐line directional couplers realised in inhomogeneous medium
Authors: Piekarz Ilona , Sorocki Jakub , Wincza Krzysztof , Gruszczynski Slawomir , Papapolymerou John
Published: May 2019

In this study, a generalised approach for the design of high‐performance differentially fed coupled‐line directional couplers in inhomogeneous medium is presented for the first time. Conditions for the realisation of ideal coupled‐line section under differential excitation are provided and it is shown that generally in such medium couplers feature different capacitive and inductive coupling coefficients, which significantly deteriorate circuits' performance. Therefore, the compensation technique is proposed allowing for equalisation of the differential coupling coefficients by adding appropriate compensating elements to the per‐unit‐length capacitance and inductance matrices of the coupled‐line section. The proposed approach allows for realisation of quasi‐ideal differential coupled‐line couplers designed in arbitrarily chosen dielectric stack‐up, and almost for arbitrarily chosen coupling. The provided theoretical analysis and resulting design methodology are verified experimentally with a 3‐dB differential coupler operating at f0 = 1.5 GHz and realised in suspended microstrip technique. Moreover, a combination of laminate and additive manufacturing technologies was used for higher design flexibility and low‐cost manufacturing.
Design and radiation mechanism analysis of a multi‐usage ultra‐high frequency radio frequency identification tag antenna
Authors: Tang Tao , She Ying , Deng Xiaobo , Wen Guangjun
Published: May 2019

A novel ultra‐high frequency radio frequency identification tag antenna designed for multi‐usage is proposed in this study, which can work on the human body, blood bags, and water‐filled container as well as free space. The tag antenna is fabricated on the F4B‐2 substrate, whose relative permittivity is 2.65 and dielectric loss tangent is 0.002. The radiation unit is formed by four main circular loops, two semicircle loops, and four round arcs, all these loops and arcs are surrounded by an elliptical loop located on the outer edge of the substrate. The antenna has an elliptical structure, whose long axis and short axis are 76, 32 mm, respectively. In different applications, the presented antenna maintains a stable operating frequency and has good conjugate impedance matching with the tag chip.
Photometry of K2 Campaign 9 bulge data
Authors: Poleski R. , Penny M. , Gaudi B. S. , Udalski A. , Ranc C. , Barentsen G. , Gould A.
Published: May 2019

In its Campaign 9, K2 observed dense regions toward the Galactic bulge in order to constrain the microlensing parallaxes and probe for free-floating planets. Photometric reduction of the K2 bulge data poses a significant challenge due to a combination of the very high stellar density, large pixels of the Kepler camera, and the pointing drift of the spacecraft. Here we present a new method to extract K2 photometry in dense stellar regions. We extended the Causal Pixel Model developed for less-crowded fields, first by using the pixel response function together with accurate astrometric grids, second by combining signals from a few pixels, and third by simultaneously fitting for an astrophysical model. We tested the method on two microlensing events and a long-period eclipsing binary. The extracted K2 photometry is an order of magnitude more precise than the photometry from other method.
IRAS 23385+6053: an embedded massive cluster in the making
Authors: Cesaroni R. , Beuther H. , Ahmadi A. , Beltrán M. T. , Csengeri T. , Galván-Madrid R. , Gieser C. , Henning T. , Johnston K. G. , Klaassen P. D. , Kuiper R. , Leurini S. , Linz H. , Longmore S. , Lumsden S. L. , Maud L. T. , Moscadelli L. , Mottram J. C. , Palau A. , Peters T. , Pudritz R. E. , Sánchez-Monge Á. , Schilke P. , Semenov D. , Suri S. , Urquhart J. S. , Winters J. M. , Zhang Q. , Zinnecker H.
Published: May 2019

Context.This study is part of the CORE project, an IRAM/NOEMA large program consisting of observations of the millimeter continuum and molecular line emission towards 20 selected high-mass star-forming regions. The goal of the program is to search for circumstellar accretion disks, study the fragmentation process of molecular clumps, and investigate the chemical composition of the gas in these regions.

Aims.We focus on IRAS 23385+6053, which is believed to be the least-evolved source of the CORE sample. This object is characterized by a compact molecular clump that is IR-dark shortward of 24μm and is surrounded by a stellar cluster detected in the near-IR. Our aim is to study the structure and velocity field of the clump.

Methods.Observations were performed at ~1.4 mm and employed three configurations of NOEMA and additional single-dish maps, merged with the interferometric data to recover the extended emission. Our correlator setup covered a number of lines from well-known hot core tracers and a few outflow tracers. The angular (~0′′.45–0′′.9) and spectral (0.5 km s−1) resolutions were sufficient to resolve the clump in IRAS 23385+6053 and investigate the existence of large-scale motions due to rotation, infall, or expansion.

Results.We find that the clump splits into six distinct cores when observed at sub-arcsecond resolution. These are identified through their 1.4 mm continuum and molecular line emission. We produce maps of the velocity, line width, and rotational temperature from the methanol and methyl cyanide lines, which allow us to investigate the cores and reveal a velocity and temperature gradient in the most massive core. We also find evidence of a bipolar outflow, possibly powered by a low-mass star.

Conclusions.We present the tentative detection of a circumstellar self-gravitating disk lying in the most massive core and powering a large-scale outflow previously known in the literature. In our scenario, the star powering the flow is responsible for most of the luminosity of IRAS 23385+6053 (~3000L⊙). The other cores, albeit with masses below the corresponding virial masses, appear to be accreting material from their molecular surroundings and are possibly collapsing or on the verge of collapse. We conclude that we are observing a sample of star-forming cores that is bound to turn into a cluster of massive stars.
Comparing Outcomes for Fasciocutaneous versus Muscle Flaps in Foot and Ankle Free Flap Reconstruction
Authors: Lee Z-Hye , Abdou Salma A. , Daar David A. , Anzai Lavinia , Stranix John T. , Thanik Vishal , Levine Jamie P. , Saadeh Pierre B.
Published: May 2019

Background The distal lower extremity poses unique reconstructive challenges due to its requirements for durability of the load-bearing plantar surface and for thin, pliable contour in the dorsal foot and ankle region. This study compares outcomes between muscle and fasciocutaneous flaps in patients with foot and ankle defects.

Methods A retrospective review of soft tissue free flaps used for traumatic foot and ankle defects was performed. Outcomes included takebacks, partial flap failure, total flap failure, and wound complications.

Results A total of 165 cases met inclusion criteria, with muscle flaps (n = 110) comprising the majority. Defects involving the non–weight-bearing surface were more common (n = 86) than those of the weight-bearing surface (n = 79). Complications occurred in 56 flaps (33.9%), including 11 partial losses (6.7%) and 6 complete losses (3.6%). There were no differences in take backs, partial flap failure, or total flap failure between muscle and fasciocutaneous flaps; however, fasciocutaneous flaps had significantly fewer wound complications compared with muscle flaps (7.3% vs. 19.1%, p = 0.046). On multivariable regression analysis, defects of the weight-bearing surface had significantly increased risk of wound breakdown compared with those in the non–weight-bearing surface (odds ratio: 5.05, p = 0.004).

Conclusion Compared with fasciocutaneous flaps, muscle flaps demonstrated higher rates of wound complications. While the flap selection in foot and ankle reconstruction depends on the nature of the defect, our findings support the use of fasciocutaneous over muscle flaps in this region.
Heterodyne-detected sum frequency generation of water at surfaces with varying hydrophobicity
Authors: Sanders Stephanie E. , Petersen Poul B.
Published: May 2019

Aqueous surfaces mediate many atmospheric, biological, and technological processes. At the interface, the bulk hydrogen-bonding network is terminated and the interfacial water molecules restructure according to the surface chemistry of the interface. Given the complexity of both natural and technical aqueous interfaces, self-assembled monolayers provide a platform for controllably tuning the chemical composition of the surface and thus the water restructuring. Here, we study a hydrophobic monolayer, a hydrophilic monolayer, and a mixed hydrophobic/hydrophilic monolayer in contact with water. Monolayers composed of both hydrophilic and hydrophobic chains mimic the complex and heterogeneous chemical composition of natural and technological surfaces. By employing heterodyne-detected sum frequency generation, the purely absorptive vibrational line shape of interfacial water is measured experimentally. We examined the structure of the interfacial water in contact with each of the monolayers by analyzing the relative dipole moment orientations and fitting the imaginary component of χ(2) with a combination of Lorentzian and Gaussian line shapes. For all of the monolayers, the hydrogen-bonded water points toward the monolayer, which is opposite of the orientation of the hydrogen-bonded water at the air-water interface. Additionally, a strongly hydrogen-bonded water species exists for the monolayers containing hydrophilic chains. The spectroscopic results suggest that the microscopic water structure in contact with the mixed monolayer is dominated by the hydrophilic parts of the monolayer, while the contact angle shows that at the macroscopic level the surface properties lie closer to the pure hydrophobic monolayer.
Band gap renormalization in n-type GeSn alloys made by ion implantation and flash lamp annealing
Authors: Prucnal S. , Berencén Y. , Wang M. , Rebohle L. , Kudrawiec R. , Polak M. , Zviagin V. , Schmidt-Grund R. , Grundmann M. , Grenzer J. , Turek M. , Droździel A. , Pyszniak K. , Zuk J. , Helm M. , Skorupa W. , Zhou S.
Published: May 2019

The last missing piece of the puzzle for the full functionalization of group IV optoelectronic devices is a direct bandgap semiconductor made by CMOS compatible technology. Here, we report on the fabrication of GeSn alloys with Sn concentrations up to 4.5% using ion implantation followed by millisecond-range explosive solid phase epitaxy. The n-type single crystalline GeSn alloys are realized by co-implantation of Sn and P into Ge. Both the activation of P and the formation of GeSn are performed during a single-step flash lamp annealing for 3 ms. The bandgap engineering in GeSn as a function of the doping level and Sn concentration is theoretically predicted by density functional theory and experimentally verified using ellipsometric spectroscopy. We demonstrate that both the diffusion and the segregation of Sn and P atoms in Ge are fully suppressed by millisecond-range nonequilibrium thermal processing.
Interface-phonon–electron interaction potentials and dispersion relations in III-nitride-based structures
Authors: Singh Ramji , Dutta Mitra , Stroscio Michael A. , Birdwell A. Glen , Amirtharaj Paul M.
Published: May 2019

In dimensionally confined multilayer heterostructures, phonons that are joint modes of the materials composed of these heterostructures are known to exist over specific frequency ranges. These modes, known as interface phonons, can exhibit phonon-electron interactions that are enhanced as the thicknesses of the layers of the heterostructure are reduced in size to about 10 nm or less. These modes have been shown to be important in phonon engineering and have been applied in optoelectronic and electronic devices, primarily for semiconductor heterostructures with underlying cubic lattices, with few studies existing for heterostructures based on wurtzite III-nitride. Motivated by applications of interface modes in ternary-based nitride structures, such as heat transport, this paper presents generalized expressions for the phonon-electron Fröhlich interactions as well as the dispersion relations for these joint modes for the technologically important case of III-nitride materials. Frequency conditions are found to restrict the existence of interface modes as illustrated through several structures.
Effects of compressive stress on electric-field-induced phase transition of antiferroelectric ceramics
Authors: Xu Ran , Golinveaux Frederick S. , Sheng Michael , Xu Zhuo , Feng Yujun , Lynch Christopher S.
Published: May 2019

In certain lead zirconate titanate compositions, the antiferroelectric (AFE) phase can be driven to the ferroelectric (FE) phase by electric field, and the induced FE phase can either revert to AFE or remain FE upon removal of the electric field. This results in a double or single hysteresis loop, respectively. To further explore the effects of the FE-AFE phase transition on electrical energy storage and conversion, two types of AFE ceramics were fabricated, and the effects of compressive stress on the AFE-FE phase transition were investigated. Compressive stress suppresses the volume increase associated with the AFE-FE transition, thus hindering the phase transition. Compressive stress also hinders polarization orientation in the FE phase, thus increasing the field necessary to achieve saturation polarization. For AFE compositions displaying a double hysteresis loop, the electrical energy storage performance can be enhanced by compressive stress. For the AFE compositions with a single hysteresis loop, the remanent polarization of the induced FE phase decreased and the coercive field did not change much within the range of compressive stress applied. In addition, the remanent polarization was reduced by 50% under a compressive stress of 126 MPa, indicating that this composition is a candidate for mechanical-electrical energy conversion.
Enhanced photocatalytic and photoelectrochemical performance of g-C3N4/BiVO4 heterojunction: A combined experimental and theoretical study
Authors: Jiang Tianqi , Nan Feng , Zhou Ju , Zheng Fengang , Weng Yuyan , Cai Tian-Yi , Ju Sheng , Xu Bin , Fang Liang
Published: May 2019

Semiconductor-based photocatalytic technology is regarded as a promising strategy for solve environmental and energy problems. Here, g-C3N4/BiVO4 heterojunction photocatalysts were prepared by a modified sol-gel technique by varying the weight ratio of g-C3N4 under facile conditions. The incorporation of g-C3N4 is found to significantly improve the photocatalytic and photoelectrochemical activity of BiVO4. The optimized g-C3N4/BiVO4 sample exhibits a greatly improved kinetic constant in photocatalytic degradation that is 7.7 times of that in pure BiVO4, and an enhancement of 3 time for the photocurrent density. Systematic experimental studies, combined with first-principles calculations, reveal that the improved photocatalytic and photoelectrochemical activities arise from the efficient separation of charge carriers due to the heterojunctions formed between g-C3N4 and BiVO4. Our work provides a feasible route to develop a high-efficiency photocatalytic technology for environmental contaminants degradation and renewable energy.
Effect of pressure-dilatation on energy spectrum evolution in compressible turbulence
Authors: Praturi Divya Sri , Girimaji Sharath S.
Published: May 2019

The effect of internal-kinetic energy exchange on transient spectral energy transfer in compressible turbulence is investigated. We derive the spectral evolution equations for kinetic energy and pressure fields to highlight the key mechanisms that affect the turbulence spectral evolution. Direct numerical simulations of decaying isotropic turbulence are performed from solenoidal, dilatational, and mixed velocity initial conditions. It is shown that internal-kinetic energy exchange arising due to pressure-dilatation renders the dilatational kinetic energy amplitudes at large scales of motion to be oscillatory. The oscillatory behavior of amplitude diminishes with increasing wavenumber. The dilatational energy spectrum also exhibits a wider range of scales due to its inherent tendency to form shocks. The findings are expected to lead to an improved understanding of energy dynamics in high-speed compressible flows.
Calibration of a lattice model for high-molecular-weight block copolymer melts
Authors: Willis J. D. , Beardsley T. M. , Matsen M. W.
Published: May 2019

The Morse calibration is applied to a lattice model designed for efficient simulations of two-component polymer melts of high molecular weight. The model allows multiple occupancy per site, which results in high invariant polymerization indices, and interactions are limited to monomers within the same site, which enhances the computational speed. The calibration maps the interaction parameter of the lattice model, α, onto the Flory-Huggins χ parameter of the standard Gaussian-chain model, by matching the disordered-state structure function, S(k), of symmetric diblock copolymers to renormalized one-loop predictions. The quantitative accuracy of the calibration is tested by comparing the order-disorder transition of symmetric diblock copolymer melts to the universal prediction obtained from previous simulations. The model is then used to confirm the universality of fluctuation corrections to the critical point of symmetric binary homopolymer blends.
Type I GaSb1-xBix/GaSb quantum wells dedicated for mid infrared laser applications: Photoreflectance studies of bandgap alignment
Authors: Kudrawiec R. , Kopaczek J. , Delorme O. , Polak M. P. , Gladysiewicz M. , Luna E. , Cerutti L. , Tournié E. , Rodriguez J. B.
Published: May 2019

To determine the band alignment at the GaSb1-xBix/GaSb interface, a set of GaSb1-xBix/GaSb quantum wells (QWs) of various widths (7, 11, and 15 nm) and contents (Bi ≤ 12%) were grown by molecular beam epitaxy and investigated by photoreflectance (PR) spectroscopy. In PR spectra, the optical transitions related to both the ground and the excited states in the QW were clearly observed. It is a direct experimental evidence that the GaSb1-xBix/GaSb QW is a type-I QW with a deep quantum confinement in both the conduction and valence bands. From the comparison of PR data with calculations of energies of QW transitions performed for the varying valence band offset (VBO), the best agreement between experimental data and theoretical calculations has been found for the VBO ∼50 ± 5%. A very similar VBO was obtained from ab initio calculations. These calculations show that the incorporation of Bi atoms into a GaSb host modifies both the conduction and valence band: the conduction-band position changes linearly at a rate of ∼15–16 meV per % Bi and the valence band position changes at a rate of ∼15–16 meV per % Bi. The calculated shifts of valence and conduction bands give the variation of VBO between GaSb1-xBix and GaSb in the range of ∼48%–52%, which is in good agreement with conclusions derived from PR measurements. In addition, it has been found that the electron effective mass reduces linearly with the increase in Bi concentration (x): meffGaSbBi=meffGaSb−0.2x, where meffGaSb is the electron effective mass of GaSb. Moreover, a strong photoluminescence (PL) was observed and a negligible Stokes shift (less than a few meV) between the PL peak and the fundamental transition in the PR spectrum was detected for all QWs at low temperatures. It means that the investigated QWs are very homogeneous, and the carrier localization for this alloy is very weak in contrast to other dilute bismides.
Rates of adsorption and desorption: Entropic contributions and errors due to mean-field approximations
Authors: Agarwal Vishal , Metiu Horia
Published: May 2019

We have performed exact classical rate calculations to compute adsorption and desorption rate constants with a model representative of a real system. We compute the desorption rate using transition-state theory by taking the dividing-surface far from the surface of the solid. We find that using a mean-field assumption, i.e., applying potential of mean force to transition state theory, could lead to two orders-of-magnitude errors in the rate constant owing to large fluctuations in the desorption barrier. Furthermore, we compute the adsorption rate by including a dynamical factor which reflects the probability of sticking to the solid surface. We find that the sticking probability is highly sensitive to the coverage. Also, we find that the adsorption rate computed from the mean-field assumption is not very different from the exact adsorption rate. We also compute entropic contribution to desorption rates and compare it to that obtained from two limiting models of adsorption—2D ideal gas and 2D ideal lattice gas. We show that at high temperatures (700 K), the entropic contribution to desorption rates computed from the exact calculations is very close to that obtained from the 2D ideal gas model. However, for lower to intermediate temperatures from 200 K to 500 K, the entropic contributions cover a wide range which lies in between the two limiting models and could lead to over two-orders-of-magnitude errors in the rate coefficient.
Dielectric breakdown properties of CF3I-N2 mixtures containing a small amount of SF6
Authors: Zhao Hu , Deng Yunkun , Tian Zengyao
Published: May 2019

CF3I-N2 mixtures have garnered much attention as potential SF6-substitutes due to their excellent dielectric strengths, and the dielectric strength of SF6-N2 mixtures has a good synergy effect. This paper attempts to propose an approach of adding a small amount of SF6 to improve the dielectric strength of the CF3I-N2 mixture, by making an all-around consideration of dielectric strength, impact on the environment and the limitations of engineering pressure and the lowest ambient temperature. The influences of adding different amounts of SF6 on the electron energy distribution function, the reduced ionization, attachment and effective ionization coefficients, the critical reduced electric field strength and critical electron temperature of ternary SF6-CF3I-N2 mixtures are investigated by Boltzmann analysis. Then the relations of the critical electric fiend strength, mixed ratio and saturated vapor pressure of the ternary SF6-CF3I-N2 mixture are built and analyzed. The results demonstrate that an effective improvement of its dielectric strength can be obtained by adding a small amount of SF6 into the CF3I-N2 mixture, and that a proper choice of the mixed ratio and the gas pressure of the ternary SF6-CF3I-N2 mixture can provide a comparable dielectric strength to pure SF6.
Design, modeling and theoretical analysis of a novel dual-axis hair flow sensor based on mode localization of weakly coupled resonators
Authors: Guo Xin , Yang Bo , Li Cheng
Published: May 2019

This paper presents the design, modeling and theoretical analysis of a novel dual-axis hair flow sensor (DHFS) based on the mode localization of weakly coupled resonators (WCRs). A stereoscopic hair post is adopted to interact with external fluid and transmit the air flow velocity signal. Two-stage micro-leverage mechanisms are designed and optimized to amplify the drag force derived from external air flow. As the main sensitive elements, four optimized WCRs are symmetrically distributed around the main frame. A simplified theoretical model of DHFS is established and verified by comprehensive finite element method (FEM) simulations. Unlike the traditional frequency detection method, the presented DHFS detects the air flow velocity by measuring the amplitude ratio shift of two degree of freedom WCRs. The input-output response simulations demonstrate that the presented DHFS exhibits an x-axis sensitivity of 6.5026×10-2/(m/s)2 and a y-axis sensitivity of 6.4527×10-2/(m/s)2. In addition, the simulated relative shift in amplitude ratio (∼65000 ppm/(m/s)2) is three orders of magnitude larger than that in resonance frequency (∼50 ppm/(m/s)2). Meanwhile, the cross-axis sensitivities are 6.4387×10-4/(m/s)2 (x-axis) and 6.4475×10-4/(m/s)2 (y-axis), respectively. In summary, the feasibility of proposed structure architecture and operation principle is verified.
Mid-infrared (3–8 μm) Ge1−ySny alloys (0.15 < y < 0.30): Synthesis, structural, and optical properties
Authors: Xu Chi , Wallace Patrick M. , Ringwala Dhruve A. , Chang Shery L. Y. , Poweleit Christian D. , Kouvetakis John , Menéndez José
Published: May 2019

Ge1−ySny alloys with compositions in the 0.15 < y < 0.30 range have been grown directly on Si substrates using a chemical vapor deposition approach that allows for growth temperatures as high as 290 °C. The films show structural properties that are consistent with results from earlier materials with much lower Sn concentrations. These include the lattice parameter and the Ge-Ge Raman frequency, which are found to depend linearly on composition. The simplicity of the structures, directly grown on Si, makes it possible to carry out detailed optical studies. Sharp absorption edges are found, reaching 8 μm near y = 0.3. The compositional dependence of edge energies shows a cubic deviation from the standard quadratic alloy expression. The cubic term may dramatically impact the ability of the alloys to cover the long-wavelength (8–12 μm) mid-IR atmospheric window.
Bending stress analysis of a piezoelectric nanoplate with flexoelectricity under inhomogeneous electric fields
Authors: Guo Yan , Ma Tingfeng , Wang Ji , Huang Bin , Kim Heung Soo
Published: May 2019

Flexoelectricity has been found as an unneglectable electro-mechanical coupling effect in micro/nanoscale dielectric materials. We present a stress function based bending stress analysis method for piezoelectric nanoplate under inhomogeneous electric fields considering both piezoelectric effect and flexoelectric effect in this work. A Ritz type solution procedure is developed by means of the quasi-three dimensional stress functions with the initial assumption of out-of-plane stress functions. A standard eigenvalue problem is constructed to obtain the general solutions of governing equations which are obtained by the principle of complementary virtual work. For the numerical analysis, we investigate the bending stresses in laminated piezoelectric nanoplate with or without flexoelectricity and the size-dependent effect on the bending stress distributions. Two kinds of inhomogeneous electric fields are considered for discussion. The present work is expected to help understanding the influence of flexoelectric effect on the bending stress distributions for the future design and application of piezoelectric nanostructures.