bluuebunny/crossref_metadata_2025 huggingface dataset:
Correction: The mechanism of ultrafast supercapacitors
Authors: Eftekhari Ali
Published: December 2019

Correction for ‘The mechanism of ultrafast supercapacitors’ by Ali Eftekhari et al., J. Mater. Chem. A, 2018, 6, 2866–2876.
Biomolecular detection, tracking, and manipulation using a magnetic nanoparticle-quantum dot platform
Authors: Mahajan Kalpesh D. , Ruan Gang , Vieira Greg , Porter Thomas , Chalmers Jeffrey J. , Sooryakumar R. , Winter Jessica O.
Published: December 2019

Fluorescent and magnetic materials play a significant role in biosensor technology, enabling sensitive quantification and separations with applications in diagnostics, purification, quality control, and therapeutics.
Facile phase transfer of hydrophobic Fe3O4@Cu2−xS nanoparticles by red blood cell membrane for MRI and phototherapy in the second near-infrared window
Authors: Lin Kecan , Cao Yanbing , Zheng Dongye , Li Qin , Liu Hui , Yu Peiwen , Li Jiong , Xue Yanan , Wu Ming
Published: December 2019

Theranostic agents for MRI and NIR II phototherapy by using red blood cell membrane for phase transfer of Fe3O4@Cu2−xS nanoparticles.
Reduced graphene oxide today
Authors: Tarcan Raluca , Todor-Boer Otto , Petrovai Ioan , Leordean Cosmin , Astilean Simion , Botiz Ioan
Published: December 2019

A summary of the most important technological applications employing reduced graphene oxide.
Accurate estimation of the photoelectric conversion efficiency of a series of anthracene-based organic dyes for dye-sensitized solar cells
Authors: Heng Panpan , Mao Lemin , Guo Xugeng , Wang Li , Zhang Jinglai
Published: December 2019

Studies demonstrate that our designed dyes 3 and 4 exhibit broad optical absorption in the 550–650 nm region and high photoelectric conversion efficiencies of over 32%.
Hybridized plasmon resonances in core/half-shell silver/cuprous oxide nanoparticles
Authors: Gale-Mouldey Alexandra , Jorgenson Emma , Coyle Jason P. , Prezgot Daniel , Ianoul Anatoli
Published: December 2019

Core/shell nanoparticles are of interest due to their attractive optical, electronic, and catalytic properties.
Bleomycin induces epithelial-to-mesenchymal transition via bFGF/PI3K/ESRP1 signaling in pulmonary fibrosis
Authors: Weng Chang-Mei , Li Qing , Chen Kui-Jun , Xu Cheng-Xiong , Deng Meng-Sheng , Li Tao , Zhang Dong-Dong , Duan Zhao-Xia , Chen Zhi-Qiang , Li Guan-Hua , Chen Jing , Wang Jian-Min
Published: December 2019

Idiopathic pulmonary fibrosis (IPF) is a fatal and chronic disease with a high rate of infection and mortality; however, its etiology and pathogenesis remain unclear. Studies have revealed that epithelial–mesenchymal transition (EMT) is a crucial cellular event in IPF. Here, we identified that the pulmonary fibrosis inducer bleomycin simultaneously increased the expression of bFGF and TGF-β1 and inhibited epithelial-specific regulatory protein (ESRP1) expression in vivo and in vitro. In addition, in vitro experiments showed that bFGF and TGF-β1 down-regulated the expression of ESRP1 and that silencing ESRP1 promoted EMT in A549 cells. Notably, we determined that bFGF activates PI3K/Akt signaling, and treatment with the PI3K/Akt inhibitor LY294002 inhibited bleomycin-induced cell morphology changes and EMT. In addition, the effects of LY294002 on bleomycin-induced EMT were inhibited by ESRP1 silencing in A549 cells. Taken together, these findings suggest that bleomycin induced EMT through down-regulating ESRP1 by simultaneously increasing bFGF and TGF-β1 in pulmonary fibrosis. Additionally, our findings indicated that bFGF inhibits ESRP1 by activating PI3K/Akt signaling.
CircRNA circPDSS1 promotes bladder cancer by down-regulating miR-16
Authors: Yu Qinnan , Liu Pei , Han Guangye , Xue Xiangdong , Ma Derong
Published: December 2019

Background: Circular RNA (circRNA) circPDSS1 is a recently identified oncogene in gastric cancer, while its roles in other types of cancer are unknown. We investigated the functions of circPDSS1 in urothelial bladder cancer (UBC).

Materials and methods: Seventy-two patients (50 males and 22 females, age 38–69 years, mean: 52.3 ± 6.3 years) with UBC were enrolled in Gansu Provincial People’s Hospital from August 2015 to August 2018. RT-qPCR was used to measure gene expression levels in both biopsies from UBC patients and in vitro cultivated HT-1197 and UMUC3 cells. Cell transfections were performed to analyze gene interactions. Cell proliferation, transwell migration and invasion assays were performed to analyze the effects of transfections on HT-1197 and UMUC3 cell proliferation, migration and invasion, respectively.

Results: We found that circPDSS1 was up-regulated in UBC. Expression levels of circPDSS1 were increased with increase in clinical stages. MiR-16 was down-regulated and correlated with circPDSS1 in UBC. Overexpression of circPDSS1 led to down-regulation of miR-16, while miR-16 overexpression failed to significantly affect circPDSS1. Overexpression of circPDSS1 led to increased proliferation, invasion and migration rates of UBC cells. Overexpression of miR-16 not only led to inhibited proliferation, invasion and migration of UBC cells, but also attenuated the effects of circPDSS1 overexpression.

Conclusion: Therefore, circRNA circPDSS1 may promote UBC by down-regulating miR-16.
Obesity associated with a novel mitochondrial tRNACys 5802A>G mutation in a Chinese family
Authors: Wang Jinling , Zhao Ningning , Mao Xiaoting , Meng Feilong , Huang Ke , Dong Guanping , Ji Yanchun , Fu JunFen
Published: December 2019

A Chinese family with matrilineally inherited obesity was assessed and its clinical, genetic, and molecular profiling was conducted. Obesity was observed in matrilineal relatives (3 out of 7) of a single generation (of 3 alive generations) in this family. On pedigree analysis and sequencing of their mitochondrial DNA (mtDNA), a novel homoplasmic mutation of the mitochondrial tRNACys gene (5802A>G) was identified in these individuals. This mutation correlated with a destabilized conserved base pair in this tRNA anticodon stem. Position 30 is known to be crucial for carrying out effective codon recognition and stability of tRNA. In accordance with the importance of this conserved site, we observed that the predicted structure of tRNACys with the mutation was noticeably remodeled in a molecular dynamics simulation when compared with the isoform of the wild-type. All other 46 mutations observed in the individual’s mtDNA were known variants belonging to haplogroup D4. Thus, this is the first report that provides evidence of the association between a mutation in tRNA and an enhanced risk of maternally transmissible obesity, offering more insights into obesity and its underlying nature.
Notch3 signalling and vascular remodelling in pulmonary arterial hypertension
Authors: Morris Hannah E. , Neves Karla B. , Montezano Augusto C. , MacLean Margaret R. , Touyz Rhian M.
Published: December 2019

Notch signalling is critically involved in vascular morphogenesis and function. Four Notch isoforms (Notch1–4) regulating diverse cellular processes have been identified. Of these, Notch3 is expressed almost exclusively in vascular smooth muscle cells (VSMCs), where it is critically involved in vascular development and differentiation. Under pathological conditions, Notch3 regulates VSMC switching between the contractile and synthetic phenotypes. Abnormal Notch3 signalling plays an important role in vascular remodelling, a hallmark of several cardiovascular diseases, including pulmonary arterial hypertension (PAH). Because of the importance of Notch3 in VSMC (de)differentiation, Notch3 has been implicated in the pathophysiology of pulmonary vascular remodelling in PAH. Here we review the current literature on the role of Notch in VSMC function with a focus on Notch3 signalling in pulmonary artery VSMCs, and discuss potential implications in pulmonary artery remodelling in PAH.
Ceres observed at low phase angles by VIR-Dawn
Authors: Ciarniello M. , De Sanctis M. C. , Raponi A. , Rousseau B. , Longobardo A. , Li J.-Y. , Schröder S. E. , Tosi F. , Zambon F. , Ammannito E. , Carrozzo F. G. , Frigeri A. , Rognini E. , Raymond C. A. , Russell C. T.
Published: December 2019

Context.Particulate surfaces exhibit a surge of reflectance at low phase angles, a phenomenon referred to as the opposition effect (OE). Two mechanisms are recognized as responsible for the OE: shadow hiding (SH) and coherent backscattering. The latter is typically characterized by a small angular width of a few degrees at most and according to the theoretical prediction should exhibit wavelength and albedo dependence.

Aims.We characterize the OE on the surface of Ceres using Dawn Visible InfraRed mapping spectrometer hyperspectral images at low phase angles. Furthermore, this dataset, coupled with previous observations, allows us to perform a complete spectrophotometric modeling at visual-to-infrared (VIS-IR) wavelengths (0.465–4.05μm) in the broad phase angle range ≈0°−132°.

Methods.We applied Hapke’s theory to the average phase curve for Ceres. Disk-resolved properties of the OE were investigated through an empirical model.

Results.Across the investigated phase angle interval, Ceres’ average phase curve exhibits a smaller back-scattering contribution for increasing wavelengths. This determines a progressive spectral reddening at larger phase angles that we hypothesize as being related to the effect of submicron roughness on the grain surface. In the OE region, the shape of the phase curves is fairly constant across the VIS range and no sharp opposition surge at very small phase angles (α< 2°) can be recognized. This would suggest a major contribution from SH to Ceres’ OE. Assuming SH as the dominant mechanism, from the OE angular width we infer a high surface porosity (≈0.9), which appears in good qualitative agreement with Ceres’ low thermal inertia. Thanks to the OE observations we derive Ceres’ VIS-IR geometric albedo with a reference value at 0.55μm of 0.098 ± 0.007. Mapping of the VIS normal albedo and OE angular width across a portion of the surface of Ceres does not reveal a spatial correlation between these quantities, consistent with SH dominating in theα= 0°−7° interval. The comparison of Ceres’V-band magnitude curve with that of other asteroids indicates that Ceres’ OE is typical of a low-albedo object and compatible with the C-class type.
Cosmology from large-scale structure
Authors: Tröster Tilman , Sánchez Ariel. G. , Asgari Marika , Blake Chris , Crocce Martín , Heymans Catherine , Hildebrandt Hendrik , Joachimi Benjamin , Joudaki Shahab , Kannawadi Arun , Lin Chieh-An , Wright Angus
Published: December 2019

We reanalyse the anisotropic galaxy clustering measurement from the Baryon Oscillation Spectroscopic Survey (BOSS), demonstrating that using the full shape information provides cosmological constraints that are comparable to other low-redshift probes. We find Ωm= 0.317+0.015−0.019,σ8= 0.710±0.049, andh = 0.704 ± 0.024 for flat ΛCDM cosmologies using uninformative priors on Ωch2, 100θMC, ln1010As, andns, and a prior on Ωbh2that is much wider than current constraints. We quantify the agreement between thePlanck2018 constraints from the cosmic microwave background and BOSS, finding the two data sets to be consistent within a flat ΛCDM cosmology using the Bayes factor as well as the prior-insensitive suspiciousness statistic. Combining two low-redshift probes, we jointly analyse the clustering of BOSS galaxies with weak lensing measurements from the Kilo-Degree Survey (KV450). The combination of BOSS and KV450 improves the measurement by up to 45%, constrainingσ8 = 0.702 ± 0.029 andS8= σ8Ωm/0.3 = 0.728 ± 0.026. Over the full 5D parameter space, the odds in favour of a single cosmology describing galaxy clustering, lensing, and the cosmic microwave background are 7 ± 2. The suspiciousness statistic signals a 2.1 ± 0.3σtension between the combined low-redshift probes and measurements from the cosmic microwave background.
The OpenRadiation project: monitoring radioactivity in the environment by and for the citizens
Authors: Bottollier-Depois J.F. , Allain E. , Baumont G. , Berthelot N. , Darley G. , Ecrabet F. , Jolivet T. , Lebeau-Livé A. , Lejeune V. , Quéinnec F. , Simon C. , Trompier F.
Published: December 2019

After the Fukushima accident, initiatives emerged offering the public the possibility to realise measurements of the radioactivity in the environment with various devices and to share data and experiences through collaborative tools. The objective of the OpenRadiation project is to offer the public the opportunity to perform measurements of the radioactivity using connected dosimeters on smartphones. The challenge is to operate such a system on a sustainable basis in normal situations and in order to be useful in an emergency situation. In normal situations, this project is based on a collaborative approach including pedagogical activities. In case of emergency situation, data from the field will be available in “real time” providing an opportunity for the emergency management and the communication with the public. The practical objectives are to develop i) a website centralising measurements using various dosimeters, providing dose rate maps with raw and filtered data and offering dedicated areas for specific projects and exchanges about data and ii) a dosimetric app using a connected dosimeter. This project is conducted within a partnership between organisms’ representative of the scientific community and associations to create links with the public.
Novel Biology of Tachykinins in Gonadotropin-Releasing Hormone Secretion
Authors: Leon Silvia , Navarro Víctor M.
Published: December 2019

The tachykinin family of peptides, composed of the neurokinins A and B (NKA, NKB) and substance P are involved in the central control of gonadotropin-releasing hormone (GnRH) release through a variety of neuronal circuitries that mediate the activation of Kiss1 neurons and the synchronization of their activity within the arcuate nucleus. The major outcome of this role is the precise regulation of the pulsatile pattern of GnRH release. In addition, tachykinins are involved in the maturation of the reproductive axis by determining the optimal timing of puberty onset, as well as in the timing of the preovulatory luteinizing hormone surge in females. Therefore, the action of tachykinins in reproduction appears to extend to all the critical aspects required for the successful attainment and maintenance of fertility. In this review, we summarize the latest advances in our understanding of the biology of tachykinins in the control of GnRH release, addressing the existing controversies, open questions, and future perspectives.
Choosing Discourse Outcome Measures to Assess Clinical Change
Authors: Boyle Mary
Published: December 2019

Surveys of speech-language pathologists who work with people with aphasia indicate that they view the large number of existing measures to be a barrier to using discourse analysis in their practice. This article provides a process that can help determine whether a particular discourse outcome measure might be useful with a particular client. The process involves answering questions about the client, the treatment, the work setting, and the psychometric properties of the discourse outcome measure in question. By following this systematic process, clinicians can eliminate outcome measures that are not likely to provide useful data and can focus on those that can help them demonstrate treatment-related change.
En Plaque Meningiomas: A Narrative Review
Authors: Elder Theresa A. , Yokoi Hana , Chugh A. Jessey , Lagman Carlito , Wu Osmond , Wright Christina Huang , Ray Abhishek , Bambakidis Nicholas
Published: December 2019

Background En plaque meningiomas are a rare subtype of meningiomas that are frequently encountered in the spheno-orbital region. Characterized by a hyperostotic and dural invasive architecture, these tumors present unique diagnostic and treatment considerations.

Objective The authors conduct a narrative literature review of clinical reports of en plaque meningiomas to summarize the epidemiology, clinical presentation, diagnostic criteria, and treatment considerations in treating en plaque meningiomas. Additionally, the authors present a case from their own experience to illustrate its complexity and unique features.

Methods A literature search was conducted using the MEDLINE database using the following terminology in various combinations: meningioma, meningeal neoplasms, en plaque, skull base, spheno-orbital, and sphenoid wing. Only literature published in English between 1938 and 2018 was reviewed. All case series were specifically reviewed for sufficient data on treatment outcomes, and all literature was analyzed for reports of misdiagnosed cases.

Conclusion En plaque meningiomas may present with a variety of symptoms according to their location and degree of bone invasion, requiring a careful diagnostic and treatment approach. While early and aggressive surgical resection is generally accepted as the optimal goal of treatment, these lesions require an individualized approach, with further investigation needed regarding the role of new therapies.
Statistical reliability analysis for a most dangerous occupation: Roman emperor
Authors: Saleh Joseph Homer
Published: December 2019

Popular culture associates the lives of Roman emperors with luxury, cruelty, and debauchery, sometimes rightfully so. One missing attribute in this list is, surprisingly, that this mighty office was most dangerous for its holder. Of the 69 rulers of the unified Roman Empire, from Augustus (d. 14 CE) to Theodosius (d. 395 CE), 62% suffered violent death. This has been known for a while, if not quantitatively at least qualitatively. What is not known, however, and has never been examined is the time-to-violent-death of Roman emperors. This work adopts the statistical tools of survival data analysis to an unlikely population, Roman emperors, and it examines a particular event in their rule, not unlike the focus of reliability engineering, but instead of their time-to-failure, their time-to-violent-death. We investigate the temporal signature of this seemingly haphazardous stochastic process that is the violent death of a Roman emperor, and we examine whether there is some structure underlying the randomness in this process or not. Nonparametric and parametric results show that: (i) emperors faced a significantly high risk of violent death in the first year of their rule, which is reminiscent of infant mortality in reliability engineering; (ii) their risk of violent death further increased after 12 years, which is reminiscent of wear-out period in reliability engineering; (iii) their failure rate displayed a bathtub-like curve, similar to that of a host of mechanical engineering items and electronic components. Results also showed that the stochastic process underlying the violent deaths of emperors is remarkably well captured by a (mixture) Weibull distribution. We discuss the interpretation and possible reasons for this uncanny result, and we propose a number of fruitful venues for future work to help better understand the deeper etiology of the spectacle of regicide of Roman emperors.
Confined crowded polymers near attractive surfaces
Authors: Tripathi Kamal , Menon Gautam I. , Vemparala Satyavani
Published: December 2019

We present results from molecular dynamics simulations of a spherically confined neutral polymer in the presence of crowding particles, studying polymer shapes and conformations as a function of the strength of the attraction to the confining wall, solvent quality, and the density of crowders. The conformations of the polymer under good solvent conditions are weakly dependent on crowder particle density, even when the polymer is strongly confined. In contrast, under poor solvent conditions, when the polymer assumes a collapsed conformation when unconfined, it can exhibit transitions to two different adsorbed phases, when either the interaction with the wall or the density of crowder particles is changed. One such transition involves a desorbed collapsed phase change to an adsorbed extended phase as the attraction of the polymer towards the confining wall is increased. Such an adsorbed extended phase can exhibit a second transition to an ordered adsorbed collapsed phase as the crowder particle density is increased. The ordered adsorbed collapsed phase of the polymer differs significantly in its structure from the desorbed collapsed phase. We revisit the earlier understanding of the adsorption of confined polymers on attractive surfaces in light of our results.
Development of high-speed ion conductance microscopy
Authors: Watanabe Shinji , Kitazawa Satoko , Sun Linhao , Kodera Noriyuki , Ando Toshio
Published: December 2019

Scanning ion conductance microscopy (SICM) can image the surface topography of specimens in ionic solutions without mechanical probe–sample contact. This unique capability is advantageous for imaging fragile biological samples but its highest possible imaging rate is far lower than the level desired in biological studies. Here, we present the development of high-speed SICM. The fast imaging capability is attained by a fast Z-scanner with active vibration control and pipette probes with enhanced ion conductance. By the former, the delay of probe Z-positioning is minimized to sub-10 µs, while its maximum stroke is secured at 6 μm. The enhanced ion conductance lowers a noise floor in ion current detection, increasing the detection bandwidth up to 100 kHz. Thus, temporal resolution 100-fold higher than that of conventional systems is achieved, together with spatial resolution around 20 nm.
Averaged angle-resolved electroreflectance spectroscopy on Cu(In,Ga)Se2 solar cells: Determination of buffer bandgap energy and identification of secondary phase
Authors: Seeger Jasmin , Grutke Jonas , Weber Nico , Schützhoff Stefan , Jin Xiaowei , Schneider Reinhard , Gerthsen Dagmar , Witte Wolfram , Hariskos Dimitrios , Kiowski Oliver , Schweiger Manuel , Kalt Heinz , Hetterich Michael
Published: December 2019

Currently, the use of Zn(O,S) as buffer material for Cu(In,Ga)Se2 (CIGS) solar cells is intensely studied in order to further boost the performance of these devices. In this context, nondestructive analytical tools are needed that enable the determination of buffer bandgap energies in the complete device. To this end, we developed a spectroscopic approach based on electroreflectance (ER). From a set of measured angle-resolved ER (ARER) spectra, an averaged modulus spectrum is numerically calculated. This method suppresses the commonly observed detrimental line-shape distortions due to interference effects in the layered device structure and thus enables the determination of bandgap energies even for thin buffer layers. To verify the working principle of ARER, we first apply it to CIGS absorber and CdS buffer layers. Then, we utilize it to investigate CIGS solar cells with Zn(O,S) buffers. All ARER results are compared to the results of diffuse ER, a technique previously developed for the suppression of interference fringes. We demonstrate that ARER is the superior ER method for nondestructive bandgap determination of thin buffer layers in complete CIGS solar cells. Moreover, a Cu containing compound was determined as a secondary phase in the Zn(O,S) buffer by combined ARER studies, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy.
Reduced electrode polarization at electrode and analyte interface in impedance spectroscopy using carbon paste and paper
Authors: Awasthi Prasoon , Das Soumen
Published: December 2019

The double layer present at the interface of an electrode and an analyte causes electrode polarization (EP) in impedance spectroscopy, which hinders acquiring the actual impedance of biological samples at a lower frequency region. In this work, a novel carbon paste (CP) electrode material prepared by mixing the pencil graphite powder with transparent glue has been reported to reduce the EP by depositing its two coplanar electrodes on a chromatography paper substrate. Furthermore, two other devices having silver paste and pencil electrodes on the chromatography paper have been fabricated, analyzed for the EP, and compared with the CP electrode. The EP is quantified by fitting the impedance data to an equivalent electrical circuit having double layer capacitance as a constant phase element, and the CP electrode shows the lowest EP among the electrodes. The cyclic voltammetry analysis reveals blocking electrode property of the CP, which diminishes dc current flow at the electrode/electrolyte interface. Furthermore, the chromatography paper is found to increase the effective surface area of the deposited electrode by enhancing its surface roughness, which helps reduce the EP.
Stabilization of the boundary layer by streamwise control
Authors: Nagy Péter Tamás , Paál György
Published: December 2019

In this paper, the effect of a special active control on the Blasius boundary layer is investigated with the Orr-Sommerfeld and the Reynolds-Orr energy equations. The control moves the wall in the streamwise direction proportional to the fluctuating wall shear stress which was proposed by Józsa et al. [“Active and passive in-plane wall fluctuations in turbulent channel flows,” J. Fluid Mech. 866, 689–720 (2019)]. Our results showed that the negative proportional parameters destabilize the flow, while the positive values lead to a contradictory outcome. According to the Orr-Sommerfeld equation, with the right choice of the parameter, the critical Reynolds number can be significantly increased. At the same time, the Reynolds-Orr equation predicts that any streamwise movement of the wall proportional to the wall shear stress slightly destabilizes the flow.
Fine structure of another blue luminescence band in undoped GaN
Authors: Reshchikov Michael A.
Published: December 2019

A blue luminescence band, labeled BL3, has been found in undoped GaN samples grown by hydride vapor phase epitaxy. It has a maximum at 2.8 eV and a phonon-related fine structure at its high-energy side. The zero-phonon line of this band consists of a duplet with two sharp lines at 3.0071 and 3.0147 eV. Three phonon modes, including the LO mode with an energy of 91.3 meV and two pseudolocal phonon modes with energies of 39.6 and 68.2 meV, form the characteristic fine structure of the BL3 band. The BL3 band is attributed to internal transitions from excited states located near the conduction band to the 0/+ transition level of unknown defect. The defect is preliminarily identified as the RY3 center, which is also responsible for bright red-yellow luminescence bands in the studied samples.
Development of sensing concrete: Principles, properties and its applications
Authors: Ding Siqi , Dong Sufen , Ashour Ashraf , Han Baoguo
Published: December 2019

Sensing concrete has the capability to sense its condition and environmental changes, including stress (or force), strain (or deformation), crack, damage, temperature, and humidity, by incorporating functional fillers. Sensing concrete has recently attracted major research interest aiming to produce smart infrastructures with elegantly integrated health monitoring abilities. In addition to having highly improved mechanical properties, sensing concrete has multifunctional properties, such as improved ductility, durability, resistance to impact, and, most importantly, self-health monitoring due to its electrical conductivity capability, allowing damage detection without the need for an external grid of sensors. This tutorial will provide an overview of sensing concrete, with attention to its principles, properties, and applications. It concludes with an outline of some future opportunities and challenges in the application of sensing concrete in the construction industry.
Dynamic study of phase transition in Bi2O3 epitaxial film induced by electrolyte gating
Authors: Fan Lele , Zhu Yiyu , Wang Zhiqiang , Zhao Sihan , Liu Zhonghu , Zhu Lei , Wang Xiaosan , Zhang Qinfang
Published: December 2019

Electrolyte gating with ionic liquids has been broadly applied in various fields in recent years. However, it remains under debate since defect-controlling and electrochemical doping are conventionally disputed to interpret the corresponding mechanism. In this work, we provide the synergistic mechanism that oxygen vacancy migration and element-doping together drive the formation of metallization. The prepared Bi2O3 films experienced insulator-metal transition and structural transformation by field-induced ionic liquid. The consequent structural transition in the Bi2O3 film was dynamically monitored by XRD, and the results indicated that an extraordinary metal Bi phase was formed during the electrolyte gating process, which was further verified by HR-TEM and XPS. Our current findings will boost the development of electrolyte gating and bring insight into other metal oxides in ionic liquid gating experiment.
Proton generation from hydrocarbon polymer targets for laser ion source
Authors: Takahashi Kazumasa , Matsumoto Yuki , Kuzumoto Masayuki , Sasaki Toru , Kikuchi Takashi
Published: December 2019

A laser ion source can provide intense pulsed ion beams from a solid target. On the other hand, generation of a proton beam with a laser ion source requires using compound targets containing hydrogen. In this research, we demonstrated proton generation from three kinds of hydrocarbon polymer targets: polyethylene (C2H4)n, polypropylene (C3H6)n, and polystyrene (C8H8)n. The laser used was a Nd:YAG laser (532 nm/17 ns), and the energy was 0.2 J. The ion current and the fraction of ion species were measured using a Faraday cup and an electrostatic ion analyzer. The results indicated that the peak currents and fraction to total particle number of proton were similar for the different hydrocarbon polymer targets and also showed that increasing the laser intensity effectively increases the number of proton particles because the larger the laser intensity, the larger the total charge.
Statistical distributions of the tuning and coupling collective modes at a conical intersection using the hierarchical equations of motion
Authors: Mangaud Etienne , Lasorne Benjamin , Atabek Osman , Desouter-Lecomte Michèle
Published: December 2019

We investigate the possibility of extracting the probability distribution of the effective environmental tuning and coupling modes during the nonadiabatic relaxation through a conical intersection. Dynamics are dealt with an open quantum system master equation by partitioning a multistate electronic subsystem out of all the nuclear vibrators. This is an alternative to the more usual partition retaining the tuning and coupling modes of a conical intersection in the active subsystem coupled to a residual bath. The minimal partition of the electronic system generally leads to highly structured spectral densities for both vibrational baths and requires a strongly nonperturbative non-Markovian master equation, treated here by the hierarchical equations of motion (HEOMs). We extend—for a two-bath situation—the procedure proposed by Shi et al. [J. Chem. Phys. 140, 134106 (2014)], whereby the information contained in the auxiliary HEOM matrices is exploited in order to derive the nuclear dissipative wave packet, i.e., the statistical distribution of the displacement of the two tuning and coupling collective coordinates in each electronic state and the coherence. This allows us to visualize the distribution, all along the nonadiabatic decay. We explore a large parameter space for a symmetrical conical intersection model and a symmetrical initial Franck-Condon preparation. Some parameters could be controlled by external fields, while others are molecule dependent and could be designed by molecular engineering. We illustrate the relation between the strongly coupled electronic and bath dynamics together with a geometric measure of non-Markovianity.
Internal quantum efficiency measurements in InAs/GaSb superlattices for midinfrared emitters
Authors: Muhowski A. J. , Muellerleile A. M. , Olesberg J. T. , Prineas J. P.
Published: December 2019

The internal quantum efficiency of a series of InAs/GaSb superlattices was investigated as a function of carrier generation rate through variable excitation, quasicontinuous-wave photoluminescence measurements. GaSb thicknesses were varied to maximize the internal quantum efficiency for midwave infrared emission. Internal quantum efficiencies were determined from measurements of the photoluminescence radiance and extraction efficiencies computed within a two-slab model. The peak internal quantum efficiencies varied from 15% to 29% at 77 K, which is in good agreement with expectations from InAs/GaSb superlattice light-emitting diode performance.
Wireless power transfer via dielectric loaded multi-moded split cavity resonator
Authors: Elnaggar Sameh Y. , Saha Chinmoy , Antar Yahia M.
Published: December 2019

Wireless power transfer via a dielectric loaded multimoded split cavity resonator (SCR) is proposed in this article. Unlike conventional inductive resonant coupling, the scheme enables the control of both the real and imaginary parts of the transfer impedance. It is demonstrated through measurements, analytical models, and extensive full-wave simulation that the inclusion of dielectric resonators (DRs) tuned to the SCR TE012 mode significantly enhances the system figure of merit, optimal efficiency, and maximum power transferred to the load. The effect of the DRs is shown to be related to the resonant coupling of the DR TE01δ and SCR modes, resulting in an electromagnetic induced transparencylike window. An efficiency of 70% is achieved when the transfer distance is 7 cm or half wavelength. Additionally, it was shown that the efficiency is above 40% over a relatively wide bandwidth and a wide range of optimum load impedance. A circuit model is developed that enables the decomposition of the two port network parameters into their modal contributions. Hence, it allows the comparison with conventional inductive resonant coupling systems on the fundamental level. Additionally, a vector fitting based method is proposed to calculate the circuit parameters from the measured scattering parameters.
Enhanced steering ability of the distal end of a magnetic catheter by utilizing magnets with optimized magnetization direction
Authors: Jung E. , Lee W. , Kim N. , Kim J. , Park J. , Jang G.
Published: December 2019

We developed a magnetic catheter with enhanced steering ability of the distal end by utilizing magnets with optimized magnetization directions. The proposed magnetic catheter is composed of a flexible tube and three-ring magnets that enable the magnetic catheter to be steered by controlling external magnetic fields. We analyzed the curvature of the magnetic catheter’s distal end and the vertical displacement of the magnetic catheter’s proximal end with a mathematical model using the Euler-Bernoulli beam theory, and then determined the optimal magnetization direction of each magnet. Finally, we prototyped the magnetic catheter with optimized magnetization directions and conducted several experiments to verify its effectiveness.
Anisotropic surface stresses of a solid/fluid interface: Molecular dynamics calculations for the copper/methane interface
Authors: Dreher T. , Pineau N. , Bourasseau E. , Malfreyt P. , Soulard L. , Lemarchand C. A.
Published: December 2019

The full tensorial surface stress of an interface between a face-centered cubic crystal (copper) and an isotropic liquid (methane) is computed for two crystal orientations {100} and {110} using molecular dynamics simulations. The bulk crystal orientation {100} is symmetric, whereas the {110} orientation is not. Finite size effects, which can be important in the case of an interface between an isotropic solid and a liquid, are studied in detail for the two crystal orientations. We first show that the symmetry of the surface stress tensor is that of the bulk crystal orientation. In the case of the asymmetric crystal orientation {110}, the relative difference between the components of the surface stress is substantial (∼50%). Finally, we show that finite size effects persist to much larger sizes in the case of the {100} orientation compared to the case of the {110} interface, for instance, through an artificial breakdown of the symmetry of the surface stress tensor.
Near ultraviolet enhanced 4H-SiC Schottky diode
Authors: Shen Yang , Jones Andrew H. , Yuan Yuan , Zheng Jiyuan , Peng Yiwei , VanMil Brenda , Olver Kimberley , Sampath Anand V. , Parker Cory , Opila Elizabeth , Campbell Joe C.
Published: December 2019

Silicon carbide Schottky diodes with thick i-regions are reported. Compared with previously reported p-i-n photodiodes, a shift of the absorption peak from 270 nm to 350 nm was observed. The responsivity curves of the Schottky diode are modeled and compared with the experimental data.
Energy product of cylindrical FePt@CoFe2 and FePt@Fe nanoparticles
Authors: Souza R. M. , Santos Y. S. M. , Oliveira L. L. , Nunes M. S. , Dantas Ana L. , Carriço A. S.
Published: December 2019

We report a theoretical discussion of the impact the composition on the maximum energy product ((BH)max) of core@shell FePt@CoFe2 and FePt@Fe nanocylinders. We have found that the best composition is determined by the competing trends imposed by a strong ferromagnetic core@shell interface exchange energy, and the core@shell dipolar interaction energy. The dipolar interaction has a negative impact on the nanocylinder (BH)max value, for shell thickness above a shell material dependent threshold value. We have also found that Fe is the best shell material owing to its much larger exchange stiffness.
A study on de-icing for railway turnouts using 250kHz-200W-class induction heating system
Authors: Oh Hyeong-Seok , Park Chan-Bae , Lee Seung-Hwan , Lee Jae-Bum , Kim Tae-Hyung , Lee Hyung-Woo
Published: December 2019

In this paper, to complement the capability of the existing heating system using an electric-heating wire for melting snow and ice in railway turnouts, 250kHz-200W-class Induction Heating (IH) system was designed. The IH system consists of the resonant inverter and the IH device. In order to perform the electric circuit, the electromagnetic field, and the thermal analysis, the Multi-Physics analysis for IH system was derived. In addition, IH system was compared with the existing heating system.
Flexibility of undulating magnetic microbeads swimmers
Authors: Li Yan-Hom , Chen Shao-Chun
Published: December 2019

This study uses the effect of flexibility on the propulsive efficiency of swimmers that consist of superparamagnetic particles and which are subjected to an oscillating field to control the movement in a low Reynolds number environment. To achieve nonreciprocal motion for a flexible swimmer using a simple and stable structure, two types of artificial flexible swimmers are constructed using self-assembled beads without links and the flexibility and the bending rigidity are investigated under various frequencies. At a low frequency, both the head and the tail oscillate almost synchronously with the field, which leads to a nearly rigid and reciprocal oscillation. The phase angle trajectory for the head significantly leads the tail at a higher frequency of oscillation, which results in a prominent flexible structure and propulsion generation. Furthermore, the flexibility initially increases linearly with the frequency and then reaches the highest value at a specific frequency. The instantaneous velocity of the swimmer almost linearly increases with its flexibility. The most effective oscillating frequency to manipulate the locomotion for the magnetic microbeads swimmer would be at f=7-10 Hz, which resists the amplitude and enhances the flexibility of the microswimmer. Finally, a flexible swimmer associated with a moderate high oscillating amplitude is a favorable configuration for propulsion generation.
Three-dimensional polarization vortex configuration evolution in compressed BaTiO3/SrTiO3 superlattice
Authors: Peng Di , Yang Xinhua , Jiang Wenkai
Published: December 2019

The molecular dynamics method based on the shell model was used to investigate the polarization configuration evolution in a ferroelectric superlattice under a compressive strain that increases at a constant rate. The polarization curl was used to render the polarization configurations. The evolution of vortex domains in location, shape, and size as well as their relative movement and annihilation was observed in three dimensions. It was found that two clockwise-anticlockwise vortex arrays occur in different material layers simultaneously at a compressive strain of −0.05%. With increasing compressive strain, the vortexes continually change their locations, shapes, and sizes and possibly walk across the bimaterial interface. Their lengths could be shortened through being split in the middle or partially annihilating from both ends. Different from the single material case, there are three ways for polarization vortex annihilation to occur in ferroelectric superlattice structures. Vortexes neighboring the material interface or boundaries are inclined to annihilate first, and then the others inside the material annihilate by combining with their neighboring antivortexes. These observations are very helpful for extending applications of ferroelectric superlattices.
Room-temperature ferromagnetism in C+-implanted AlN films
Authors: Ye R. , Liu J. D. , Zhang H. J. , Ye B. J.
Published: December 2019

Diluted magnetic semiconductors (DMSs) have numerous potential applications, particularly in spintronics. Therefore, the search for advanced DMSs has been a critical task for a long time. In this work, room-temperature ferromagnetism is observed in the C+-implanted AlN films with C+ doses of 5×1016 (AlN:C5×1016) and 2×1017 cm−2 (AlN:C2×1017). AlN:C2×1017 exhibits a saturation magnetization of ∼0.104 emu/g, nearly 1.5 times that of AlN:C5×1016. X-ray diffraction and X-ray photoelectron spectroscopy (XPS) measurements reveal that the implanted C+ ions occupy the interstitial lattice sites and substitute at the sites of Al atoms. XPS and Doppler broadening of positron annihilation radiation measurements demonstrate the existence of the Al-vacancy related defects in the C+-implanted AlN films. First-principles calculations indicate that the ferromagnetism in AlN:C5×1016 and AlN:C2×1017 is mainly originated from defect complexes involving interstitial C atoms and Al vacancies, which have the lowest formation energy among AlN:C defects containing C atoms and Al vacancies. This work provides a feasible route to develop advanced DMSs.
Elucidating the effects of guest-host energy level alignment on charge transport in phosphorescent OLEDs
Authors: Sanderson Stephen , Philippa Bronson , Vamvounis George , Burn Paul L. , White Ronald D.
Published: December 2019

The correct choice of guest and host molecules in the light-emitting layer is essential for developing high performance phosphorescent organic light emitting devices. However, the effects of the energy level alignment between the guest and the host are yet to be fully elucidated. In this Letter, we use kinetic Monte Carlo simulations to investigate guest-host systems in which the energy gap of the guest and host is fixed, and only the relative energies of the ionization potential/electron affinity are changed to elucidate their effect on charge transport. It was determined that the mobility balance in the blend was sensitive to the energy level alignment, allowing balanced active layer mobility to be achieved despite the hole and electron mobilities being different by around one order of magnitude. It was also found that the mobility of the faster carrier was more sensitive to the energy level alignment than that of the slower carrier due to reduced slower carrier thermalization under deep charge trapping on the guest.
Zeeman spin-splitting in the (010) β-Ga2O3 two-dimensional electron gas
Authors: Neal Adam T. , Zhang Yuewei , Elhamri Said , Rajan Siddharth , Mou Shin
Published: December 2019

Through magnetotransport measurements and analysis of the observed Shubnikov de-Haas oscillations in (010) (AlxGa1-x)2O3/Ga2O3 heterostructures, spin-splitting of the Landau levels in the (010) Ga2O3 two-dimensional electron gas (2DEG) has been studied. Analysis indicates that the spin-splitting results from the Zeeman effect. By fitting both the first and second harmonics of the oscillations as a function of magnetic field, we determine the magnitude of the Zeeman splitting to be 0.4 ħωc, with a corresponding effective g-factor of 2.7, for the magnetic field perpendicular to the 2DEG.
Physical mechanism on the suppression of dynamic resistance degradation by multi-mesa-channel in AlGaN/GaN high electron mobility transistors
Authors: Ren Kailin , Liang Yung C. , Huang Chih-Fang
Published: December 2019

In this letter, the suppression of dynamic on-state resistance (RON) degradation for faster dynamic RON recovery is achieved by the multimesa-channel (MMC) structure in AlGaN/GaN high electron mobility transistors. The measurement results are discussed with the physical mechanisms investigated. The initial transient RON degradation is reduced in the MMC structure, resulting from the lower peak electric field around the drain-side gate edge in the trigate structure compared to that in a planar device. The faster dynamic RON recovery in MMC devices is attributed to the quick emission of electrons at sidewall traps of shallower energy levels. The energy levels of dominant traps at the sidewall and top interfaces are found to be 0.26 eV and 0.37 eV below the conduction band edge, respectively, verified by Technology Computer Aided Design simulations in agreement with the measurement data.
Comparative study of methodologies for calculating metastable states of small to medium-sized molecules
Authors: Thodika Mushir , Fennimore Mark , Karsili Tolga N. V. , Matsika Spiridoula
Published: December 2019

We present a benchmarking study on the performance of two methods at the forefront of studying electronic metastable states of molecules: the orbital stabilization method and the method of complex absorbing potential augmented Hamiltonians. The performance of the two methods is compared for the calculation of shape resonances in small to medium-sized molecules (up to 15 atoms) at the equation of motion coupled cluster with singles and doubles for the electron attachment level of methodology using even-tempered Gaussian basis sets. The theoretical positions and widths of shape resonances obtained from both methods are compared to the experimentally determined electron affinities and lifetimes. The challenges that accompany the theoretical estimation of resonance positions and widths for medium to large-sized systems with an increase in basis set size are also discussed.
Detection of electron paramagnetic resonance in La0.6Ca0.4MnO3 using a copper stripcoil
Authors: Chaudhuri Ushnish , Chanda Amit , Mahendiran R.
Published: December 2019

Recently, we had reported the detection of electron paramagnetic resonance (EPR) from magnetoimpedance (MI) measurements in bulk La0.60Ca0.40MnO3 (LCMO) samples using radio frequency (rf) currents [U. Chaudhuri and R. Mahendiran, Appl. Phys. Lett. 115, 092405 (2019)]. Here, we report an alternative method which involves measuring the effective MI changes of a copper stripcoil that encloses the LCMO sample. Magnetoresistance (∆R/R0) and magnetoreactance (∆X/X0) of the sample were measured indirectly via the stripcoil for frequencies of current from f = 0.5 to 2.5 GHz. During the field sweep, ∆R/R0 shows an abrupt increase that is accompanied by a dip in ΔX/X0 at a critical value of dc magnetic field (Hc) when f ≥ 0.9 GHz. Hc increased linearly with frequency (f) of the current in the stripcoil, satisfying the EPR relation fr = (γ/2π)Hdc, where γ is the gyromagnetic ratio and fr is the resonance frequency. The same stripcoil and the sample were also used to measure microwave power absorption using a vector network analyzer. The features observed in both these techniques were strikingly similar to the results obtained from the direct MI measurement in LCMO, which confirms the electrical detection of EPR.