bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of SrI2 substitution on perovskite film formation and its photovoltaic properties via two different deposition methods
Authors: Zhang Huanyu , Li Rui , Zhang Mei , Guo Min
Published: March 2018

A 10 mol% Sr-substituted mesoscopic perovskite solar cell fabricated via a two-step spin-coating method exhibited the highest power conversion efficiency of 15.52%.
Interfacial modification of basalt fiber filling composites with graphene oxide and polydopamine for enhanced mechanical and tribological properties
Authors: Wang Junjie , Zhou Shaofeng , Huang Jin , Zhao Guizhe , Liu Yaqing
Published: March 2018

Graphene oxide was grafted onto the surface of basalt fiber via polydopamine to enhance the interfacial adhesion of PA6 composites.
Composition-induced phase evolution and high strain response in Ba(Zn1/3Nb2/3)O3-modified (Bi0.5Na0.5)TiO3-based lead-free ferroelectrics
Authors: Wei Qiumei , Zhu Mankang , Qin Tianhe , Guo Zhihua , Zheng Mupeng , Hou Yudong , Liu Hui , Chen Jun
Published: March 2018

Addition of 1.0 mol% Ba(Zn1/3Nb2/3O3) into (Bi0.5Na0.5)0.93Ba0.07TiO3 results in the decrease of the rhombohedrality and the evolution from ferroelectric to antiferroelectric relaxor, thus leads to the emergence of a large field-induced strain of 0.39%.
Fluoroalkyl ether-diluted dimethyl carbonate-based electrolyte solutions for high-voltage operation of LiNi0.5Co0.2Mn0.3O2 electrodes in lithium ion batteries
Authors: Doi Takayuki , Matsumoto Ryo , Cao Ziyang , Haruta Masakazu , Hashinokuchi Michihiro , Inaba Minoru
Published: March 2018

High-voltage operation of LiNi0.5Co0.2Mn0.3O2 positive electrodes is attained in highly concentrated LiBF4/DMC electrolyte solution because of the stabilized BF4− and DMC.
An ab initio study for probing iodization reactions on metallic anode surfaces of Li–I2 batteries
Authors: Liu Zhixiao , Hu Wangyu , Gao Fei , Deng Huiqiu
Published: March 2018

A Li oxynitride protecting layer produced by the LiNO3 additive can prohibit surface iodization and LiI exfoliation.
Insight into fast Li diffusion in Li-excess spinel lithium manganese oxide
Authors: Xiao Weiji , Xin Chao , Li Sibai , Jie Jianshu , Gu Yue , Zheng Jiaxin , Pan Feng
Published: March 2018

Li-excess configuration can enhance Li diffusion by introducing two fast channels in spinel lithium manganese oxide.
Fluorinated graphene as an anticancer nanocarrier: an experimental and DFT study
Authors: Gong Peiwei , Du Jiuyao , Wang Dandan , Cao Bobo , Tian Meng , Wang Yuhua , Sun Lu , Ji Shuaijie , Liu Zhe
Published: March 2018

Both experimental and theoretical research was conducted to explore the performance of fluorinated graphene as a novel anticancer nanocarrier, and we also reported its first application in cancer chemo-photothermal therapy.
A compliant, self-adhesive and self-healing wearable hydrogel as epidermal strain sensor
Authors: Liu Shuqi , Zheng Rongmin , Chen Song , Wu Yunhui , Liu Haizhou , Wang Pingping , Deng Zhifu , Liu Lan
Published: March 2018

A compliant, self-adhesive and self-healing epidermal strain sensor that shows excellent sensing performance at ultra-low and high strain.
A facile, robust and scalable method for the synthesis of Pd nanoplates with hydroxylamine as a reducing agent and mechanistic insights from kinetic analysis
Authors: Figueroa-Cosme Legna , Hood Zachary D. , Gilroy Kyle D. , Xia Younan
Published: March 2018

We report a simple and robust method for the synthesis of Pd nanoplates using hydroxylamine as a reductant and kinetic analysis.
Internal biliary drainage superior to external biliary drainage in improving gut mucosa barrier because of goblet cells and mucin-2 up-regulation
Authors: Tang Xuechan , Ma Weiping , Zhan Weirong , Wang Xin , Dong Huan , Zhao Hongjing , Yang Lin , Ji Cuiying , Han Qing , Ji Chenguang , Liu Hongqun , Wang Na
Published: March 2018

Backgroud: Obstructive jaundice increases intestinal permeability, but the pathological mechanisms remain obscure, which results in debates about the necessity of performing preoperative biliary drainage in patients with obstructive jaundice. Mucin-2 (MUC2) and goblet cells regulated by bile acids play an important role in maintaining the function of intestinal mucosal barrier. The present study was to investigate the role of goblet cells and MUC2 in obstructive jaundice and evaluate the effect of biliary drainage on intestinal permeability.

Study design: We enrolled patients with malignant biliary obstruction and controls. We also did animal studies with four groups of rats: sham operation, obstructive jaundice, internal biliary drainage, and external biliary drainage. Histopathological analysis, biochemical measurement, and electron microscopy examination were done on pertinent samples.

Results: Compared with the control group, the small intestinal mucosa was significantly damaged; goblet cells and MUC2 were significantly decreased and serum endotoxin level was significantly increased in patients and rats with obstructive jaundice. Biliary drainage, especially internal biliary drainage, significantly increased goblet cells and MUC2 and attenuated the damage of small intestinal mucosa.

Conclusions: In obstructive jaundice condition, goblet cells and MUC2 were reduced which were involved in the damage of intestinal mucosa barrier; biliary drainage increased goblet cells and MUC2, repaired mucosa layer and restored the intestinal mucosa barrier function.
Cryo-soft X-ray tomography: using soft X-rays to explore the ultrastructure of whole cells
Authors: Harkiolaki Maria , Darrow Michele C. , Spink Matthew C. , Kosior Ewelina , Dent Kyle , Duke Elizabeth
Published: March 2018

Cryo-soft X-ray tomography is an imaging technique that addresses the need for mesoscale imaging of cellular ultrastructure of relatively thick samples without the need for staining or chemical modification. It allows the imaging of cellular ultrastructure to a resolution of 25–40 nm and can be used in correlation with other imaging modalities, such as electron tomography and fluorescence microscopy, to further enhance the information content derived from biological samples. An overview of the technique, discussion of sample suitability and information about sample preparation, data collection and data analysis is presented here. Recent developments and future outlook are also discussed.
Recent developments in small-angle X-ray scattering and hybrid method approaches for biomacromolecular solutions
Authors: Schroer Martin A. , Svergun Dmitri I.
Published: March 2018

Small-angle X-ray scattering (SAXS) has become a streamline method to characterize biological macromolecules, from small peptides to supramolecular complexes, in near-native solutions. Modern SAXS requires limited amounts of purified material, without the need for labelling, crystallization, or freezing. Dedicated beamlines at modern synchrotron sources yield high-quality data within or below several milliseconds of exposure time and are highly automated, allowing for rapid structural screening under different solutions and ambient conditions but also for time-resolved studies of biological processes. The advanced data analysis methods allow one to meaningfully interpret the scattering data from monodisperse systems, from transient complexes as well as flexible and heterogeneous systems in terms of structural models. Especially powerful are hybrid approaches utilizing SAXS with high-resolution structural techniques, but also with biochemical, biophysical, and computational methods. Here, we review the recent developments in the experimental SAXS practice and in analysis methods with a specific focus on the joint use of SAXS with complementary methods.
Joint user selection, mode assignment, and power allocation in cognitive radio‐assisted D2D networks
Authors: Ahmad Mushtaq , Naeem Muhammad , Iqbal Muhammad , Ejaz Waleed , Anpalagan Alagan
Published: March 2018

Device to device (D2D) communications are emerging as an essential part of technological solutions to boost data rates in the next generation networks. Cognitive radio (CR) opportunistically utilises spectrum to boost spectral efficiency. CR‐assisted D2D networks will bring the benefits of both D2D as well as CR together in futuristic cellular networks. This study proposes to opportunistically use TV spectrum white spaces. A joint user selection, mode assignment, and power allocation in CR‐assisted D2D networks can definitely yield higher data rates. The proposed study maximises data rate together with users' selection fulfilling various users' power, base station's transmit power, quality of service, and interference related thresholds. This problem is mixed integer non‐linear programming and considered non‐deterministic polynomial time (NP)‐complete. Due to the discrete variables in the problem, finding an optimal solution with the help of an exhaustive search algorithm (ESA) becomes very challenging. The problem gets exponentially complex with the increasing number of user pairs. Thus, the need of another method becomes imperative that yields near optimal solution. Mesh adaptive direct search (MADS) algorithm is considered for solution in the CR‐assisted D2D network resource management problem. Simulation results using MADS yield near optimal solution confirming the suitability of MADS for CR‐assisted D2D networks.
New look at the Student's t‐based Kalman filter from maximum a posterior perspective
Authors: Qin Fangjun , Chang Lubin , Zha Feng
Published: March 2018

In this study, the newly derived Student's t‐based Kalman filter (STKF) is re‐derived from Bayesian maximum a posterior perspective for linear systems with heavy‐tailed measurement noises. This re‐derivation reveals that the STKF is an M‐estimator with Cauchy function as the robust cost function. The presented re‐derivation can also be used as the unified procedure to derive robust Kalman‐type filters by assuming the likelihood probability density function to be elliptical distributions.
Star-forming galaxies at low-redshift in the SHARDS survey
Authors: Lumbreras-Calle A. , Muñoz-Tuñón C. , Méndez-Abreu J. , Mas-Hesse J. M. , Pérez-González P. G. , Alcalde Pampliega B. , Arrabal Haro P. , Cava A. , Domínguez Sánchez H. , Eliche-Moral M. C. , Alonso-Herrero A. , Borlaff A. , Gallego J. , Hernán-Caballero A. , Koekemoer A. M. , Rodríguez-Muñoz L.
Published: March 2018

Context. The physical processes driving the evolution of star formation (SF) in galaxies over cosmic time still present many open questions. Recent galaxy surveys allow now to study these processes in great detail at intermediate redshift (0 ≤ z ≤ 0.5).

Aims. We build a complete sample of star-forming galaxies and analyze their properties, reaching systems with low stellar masses and low star formation rates (SFRs) at intermediate-to-low redshift.

Methods. We use data from the SHARDS multiband survey in the GOODS-North field. Its depth (up to magnitude ⟨m3σ⟩~ 26.5) and its spectro-photometric resolution (R ~ 50) provides us with an ideal dataset to search for emission line galaxies (ELGs). We develop a new algorithm to identify low-redshift (z < 0.36) ELGs by detecting the [OIII]5007 and Hα emission lines simultaneously. We fit the spectral energy distribution (SED) of the selected sample, using a model with two single stellar populations.

Results. We find 160 star-forming galaxies for which we derive equivalent widths (EWs) and absolute fluxes of both emission lines. We detect EWs as low as 12 Å, with median values for the sample of ~35 Å in [OIII]5007 and ~56 Å in Hα, respectively. Results from the SED fitting show a young stellar population with low median metallicity (36% of the solar value) and extinction (AV ~ 0.37), with median galaxy stellar mass ~108.5 M⊙. Gas-phase metallicities measured from available spectra are also low. ELGs in our sample present bluer colours in the UVJ plane than the median colour-selected star-forming galaxy in SHARDS. We suggest a new V-J colour criterion to separate ELGs from non-ELGs in blue galaxy samples. In addition, several galaxies present high densities of O-type stars, possibly producing galactic superwinds, which makes them interesting targets for follow-up spectroscopy.

Conclusions. We have demonstrated the efficiency of SHARDS in detecting low-mass ELGs (~2 magnitudes deeper than previous spectroscopic surveys in the same field). The selected sample accounts for 20% of the global galaxy population at this redshift and luminosity, and is characterized by young SF bursts with sub-solar metallicities and low extinction. However, robust fits to the full SEDs can only be obtained including an old stellar population, suggesting the young component is built up by a recent burst of SF in an otherwise old galaxy.
Endoskopische Interventionen beim Lungenemphysem
Authors: Gompelmann Daniela
Published: March 2018

Die endoskopische Lungenvolumenreduktion (ELVR) ist bei ausgewählten Patienten mit einem schwergradigen Lungenemphysem, die trotz Ausschöpfen der
leitliniengerechten konservativen Behandlung Symptome sowie eine erhebliche lungenfunktionelle Einschränkung aufweisen, eine additive Therapieoption. Die
Ventiltherapie, als einzige vollständig reversible Methode, führt bei Patienten mit fehlender interlobärer Kollateralventilation durch eine Atelektasenbildung
des emphysematös destruierten Lungenlappens zur Volumenreduktion. Bei den alternativen, nicht-blockierenden Techniken (Coil-Therapie, bronchoskopische
Thermoablation, polymerische Lungenvolumenreduktion), die hingegen unabhängig von der Kollateralventilation sind, wird eine Volumenreduktion durch Kompression
des Lungenparenchyms bzw. durch einen inflammatorischen Reiz induziert. Die derzeit verfügbare Datenlage ist für die endoskopische Ventiltherapie bereits
umfassend, während hingegen für die nicht-blockierenden Techniken weitere randomisierte Studien notwendig sind, um diese Verfahren mit hinreichender Evidenz zu
etablieren.
Development and validation of an automated algorithm to evaluate the abundance of bubbles in small bowel capsule endoscopy
Authors: Pietri Olivia , Rezgui Gada , Histace Aymeric , Camus Marine , Nion-Larmurier Isabelle , Li Cynthia , Becq Aymeric , Abou Ali Einas , Romain Olivier , Chaput Ulriikka , Marteau Philippe , Florent Christian , Dray Xavier
Published: March 2018

Background and study aims Bubbles can impair visualization of the small bowel (SB) mucosa during capsule endoscopy (CE). We aimed to develop and validate a computed algorithm that would allow evaluation of the abundance of bubbles in SB-CE still frames.

Patients and methods Two sets of 200 SB-CE normal still frames were created. Two experienced SB-CE readers analyzed both sets of images twice, in a random order. Each still frame was categorized as presenting with < 10 % or ≥ 10 % of bubbles. Reproducibility (κ), sensitivity (Se), specificity (Sp), receiver operating characteristic curve, and calculation time were measured for different algorithms (Grey-level of co-occurrence matrix [GLCM], fractal dimension, Hough transform, and speeded-up robust features [SURF]) using the experts’ analysis as reference. Algorithms with highest reproducibility, Se and Sp were then selected for a validation step on the second set of frames. Criteria for validation were κ = 1, Se ≥ 90 %, Sp ≥ 85 %, and a calculation time < 1 second.

Results Both SURF and GLCM algorithms had high operating points (Se and Sp over 90 %) and a perfect reproducibility (κ = 1). The validation step showed the GLCM detector strategy had the best diagnostic performances, with a Se of 95.79 %, a Sp of 95.19 %, and a calculation time of 0.037 seconds per frame.

Conclusion A computed algorithm based on a GLCM detector strategy had high diagnostic performance allowing assessment of the abundance of bubbles in SB-CE still frames. This algorithm could be of interest for clinical use (quality reporting) and for research purposes (objective comparison tool of different preparations).
Maternal Asthma Is an Independent Risk Factor for Long-Term Respiratory Morbidity of the Offspring
Authors: Shoham-Vardi I. , Goldbart A. , Sergienko R. , Sheiner E. , Spiegel E.
Published: March 2018

Objective The objective of this study was to investigate whether maternal bronchial asthma increases the risk for long-term respiratory morbidity of the offspring.

Study Design A population-based cohort study compared the incidence of long-term pediatric hospitalizations due to respiratory disease of the offspring of mothers with and without bronchial asthma. Deliveries occurred between the years 1991 and 2014 in a tertiary medical center. Congenital malformations as well as multiple pregnancies were excluded. Kaplan–Meier's survival curve was used to estimate cumulative incidence of respiratory morbidity. A multivariate generalized estimating equation (GEE) logistic regression model analysis was used to control for confounders.

Results During the study period, 253,808 deliveries met the inclusion criteria; of which 1.3% were born to mothers with bronchial asthma (n = 3,411). During the follow-up period, children born to women with bronchial asthma had a significantly higher rate of long-term respiratory morbidity (odds ratio [OR] = 1.5; 95% confidence interval [CI] = 1.3–1.7; p < 0.001). Specifically, the rate of childhood asthma was higher among offspring of mothers with asthma (OR = 2.3; 95% CI = 1.8–2.9; p < 0.001). Children born to women with asthma had higher cumulative incidence of respiratory morbidity, using a Kaplan–Meier's survival curve (log-rank test; p < 0.001). Using two multivariable GEE logistic regression models, controlling for the time to event, maternal age, and gestational age at delivery, maternal bronchial asthma was found to be an independent risk factor for long-term respiratory disease of the offspring (adjusted OR = 1.6; 95% CI = 1.4–1.9; p < 0.001), and specifically for bronchial asthma (adjusted OR = 2.5; 95% CI = 1.9–3.1; p < 0.001).

Conclusion Maternal bronchial asthma is an independent risk factor for long-term respiratory morbidity of the offspring.
Colon cleansing protocol in children: research conditions vs. clinical practice
Authors: Elitsur Yoram , Balfaqih Yaslam , Preston Deborah
Published: March 2018

Background and study aims Colon preparation rates are the limiting factor for a successful diagnostic colonoscopy in children. Different colon cleansing protocols have been published for use in children. Unfortunately, the applicability of those published research protocols has not been formally evaluated in routine clinical practice. We investigated the success rate of our previously published colon cleansing protocol as utilized in our clinical practice.

Patients and methods This was a retrospective study. In the clinical practice, the colon cleansing protocol included PEG-3350 at a dose of 2 g/kg/day plus Dulcolax (Bisacodyl, Boehringer Ingelheim, TX USA) 5 mg/day for 2 days. Adequate colon preparation was graded between 1 – 5, as previously described, and grade ≥ 4.0 was considered an adequate preparation. Patients were instructed to complete a questionnaire that included PEG-3350 dose, number of stools per day, consistency of each stool, and side effects (vomiting, abdominal pain). Clinical and endoscopic results were compared between the protocol under research conditions and routine practice.

Results The success rate of the colon preparation in our clinical practice was similar to the results observed under our research protocol (75 % vs. 73.6 %). Moreover, the total number of stools, stool consistency, and the intubation rate of the terminal ileum were also similar. We concluded, that in our experience, the colon cleansing protocol used under research conditions was effective and appropriate for use in routine clinical practice.

Conclusion We recommend testing each new protocol under the routine conditions of clinical practice to confirm its applicability for general practitioners.
Perspectives on endoscopic submucosal dissection training in the United States: a survey analysis
Authors: Schlachterman Alexander , Yang Dennis , Goddard April , Gotoda Takuji , Draganov Peter
Published: March 2018

Background and study aims Endoscopic submucosal dissection (ESD) is a widely accepted method for en-bloc resection of dysplastic lesions and early cancer in Asia and Europe. A limiting factor in adoption of ESD in the United States is perceived lack of training opportunities. The aims of this study were to: (1) evaluate ESD experience of attendees at a University-sponsored ESD training course; (2) characterize effectiveness of the current ESD training regimen and its impact on ESD adoption in the United States; and (3) gauge trainees’ attitude towards ESD.

Patients and methods An electronic anonymous survey was distributed to the 86 physicians who participated in the University of Florida’s annual ESD course from 2014 to 2016. Main outcomes included participants’ practice setting, prior training, current ESD techniques, and planned training.

Results A total of 34 participants (40 %) completed the survey. Most of the respondents routinely use one or more endoscopic mucosal resection (EMR) techniques (97.1 %) in their practice. Most respondents (79 %) had no experience with ESD on humans prior to the ESD course. Following completion of course training, more participants reported ongoing hands-on ESD exposure, with 15/34 (44 %) having performed ESD in humans. Most participants identified potential hurdles for adoption of ESD.

Conclusion A dedicated ESD training course with hands-on experience, under the guidance of experts, notably increased use of ESD among participants. Limited availability of structured training opportunities, concerns over procedural length, lack of adequate number of lesions, and potential for serious adverse events (AEs) were identified as the main factors slowing adoption of ESD in the United States.
Endoscopic versus percutaneous management for symptomatic pancreatic fluid collections: a systematic review and meta-analysis
Authors: Khan Muhammad , Hammad Tariq , Khan Zubair , Lee Wade , Gaidhane Monica , Tyberg Amy , Kahaleh Michel
Published: March 2018

Background Symptomatic pancreatic fluid collections (PFCs) are managed by surgical, percutaneous, or endoscopic drainage. Due to morbidity associated with surgical drainage, percutaneous and/or endoscopic options have increasingly been used as initial management.

Aims We conducted a systematic review and meta-analysis comparing the efficacy and safety of endoscopic versus percutaneous drainage for management of PFCs.

Methods We searched several databases from inception through 31 August 2017 to identify comparative studies using endoscopic or percutaneous drainage for PFCs. Our primary outcome was clinical success. Secondary outcomes were technical success, adverse events (AE), rates of recurrence, requirement for subsequent procedures, and length of stay in hospital. Pooled risk ratios (RR) and mean difference (MD) were calculated for categorical and continuous outcomes, respectively.

Results Seven studies with 490 patients were included in the final analysis. Pooled RR for clinical success was 0.40 (0.26, 0.61), I
2 = 42 % in favor of endoscopic management. On sensitivity analysis, after excluding one study on patients with walled-off necrosis (WON), the clinical success was 0.43 (0.28, 0.66) with no heterogeneity. Pooled RR for technical success was 1.50 (0.52, 4.37) with no heterogeneity. Pooled RR for AE and rate of recurrence were 0.77 (0.46, 1.28) and 0.60 (0.29, 1.24), respectively. Pooled MD for length of stay in hospital and rate of re-intervention were – 8.97 (– 12.88, – 5.07) and – 0.66 (– 0.93, – 0.38), respectively, in favor of endoscopic drainage.

Conclusions Endoscopic drainage should be the preferred therapeutic modality for PFCs compared to percutaneous drainage as it is associated with significantly better clinical success, a lower re-intervention rate, and a shorter hospital length of stay.

This study was presented as an abstract at Digestive Disease Week 2017 in Chicago, USA.
Upper semicontinuity of attractors of stochastic delay reaction-diffusion equations in the delay
Authors: Li Dingshi , Shi Lin
Published: March 2018

A system of stochastic delayed reaction-diffusion equations with multiplicative noise and deterministic non-autonomous forcing is considered. We first prove the existence and uniqueness of a bi-spatial pullback attractor for these equations when the initial space is C−ρ,0,L2O and the terminate space is C−ρ,0,H01O. The asymptotic compactness of solutions in C−ρ,0,H01O is established by combining “positive and negative truncations” technique and some new estimates on solutions. Then the periodicity of the random attractors is proved when the stochastic delay equations are forced by periodic functions. Finally, upper semicontinuity of the global random attractors in the delay is obtained as the length of time delay approaches zero.
Investigation on heat transfer analysis and its effect on a multi-mode, beam-wave interaction for a 140 GHz, MW-class gyrotron
Authors: Liu Qiao , Liu Yinghui , Chen Zhaowei , Niu Xinjian , Li Hongfu , Xu Jianhua
Published: March 2018

The interaction cavity of a 140 GHz, 1 MW continuous wave gyrotron developed in UESTC will be loaded with a very large heat load in the inner surface during operation. In order to reduce the heat, the axial wedge grooves of the outside surface of the cavity are considered and employed as the heat radiation structure. Thermoanalysis and structural analysis were discussed in detail to obtain the effects of heat on the cavity. In thermoanalysis, the external coolant-flow rates ranging from 20 L/min to 50 L/min were considered, and the distribution of wall loading was loaded as the heat flux source. In structural analysis, the cavity's deformation caused by the loads of heat and pressure was calculated. Compared with a non-deformed cavity, the effects of deformation on the performance of a cavity were discussed. For a cold-cavity, the results show that the quality factor would be reduced by 72, 89, 99 and 171 at the flow rates of 50 L/min, 40 L/min, 30 L/min and 20 L/min, respectively. Correspondingly, the cold-cavity frequencies would be decreased by 0.13 GHz, 0.15 GHz, 0.19 GHz and 0.38 GHz, respectively. For a hot-cavity, the results demonstrate that the output port frequencies would be dropped down, but the offset would be gradually decreased with increasing coolant-flow rate. Meanwhile, the output powers would be reduced dramatically with decreasing coolant-flow rate. In addition, when the coolant-flow rate reaches 40 L/min, the output power and the frequency are just reduced by 30 kW and 0.151 GHz, respectively.
New method for rekindling the nonlinear solitary waves in Maxwellian complex space plasma
Authors: Das G. C. , Sarma Ridip
Published: March 2018

Our interest is to study the nonlinear wave phenomena in complex plasma constituents with Maxwellian electrons and ions. The main reason for this consideration is to exhibit the effects of dust charge fluctuations on acoustic modes evaluated by the use of a new method. A special method (G′/G) has been developed to yield the coherent features of nonlinear waves augmented through the derivation of a Korteweg-de Vries equation and found successfully the different nature of solitons recognized in space plasmas. Evolutions have shown with the input of appropriate typical plasma parameters to support our theoretical observations in space plasmas. All conclusions are in good accordance with the actual occurrences and could be of interest to further the investigations in experiments and satellite observations in space. In this paper, we present not only the model that exhibited nonlinear solitary wave propagation but also a new mathematical method to the execution.
A new approach to the inverse problem for current mapping in thin-film superconductors
Authors: Zuber J. W. , Wells F. S. , Fedoseev S. A. , Johansen T. H. , Rosenfeld A. B. , Pan A. V.
Published: March 2018

A novel mathematical approach has been developed to complete the inversion of the Biot-Savart law in one- and two-dimensional cases from measurements of the perpendicular component of the magnetic field using the well-developed Magneto-Optical Imaging technique. Our approach, especially in the 2D case, is provided in great detail to allow a straightforward implementation as opposed to those found in the literature. Our new approach also refines our previous results for the 1D case [Johansen et al., Phys. Rev. B 54, 16264 (1996)], and streamlines the method developed by Jooss et al. [Physica C 299, 215 (1998)] deemed as the most accurate if compared to that of Roth et al. [J. Appl. Phys. 65, 361 (1989)]. We also verify and streamline the iterative technique, which was developed following Laviano et al. [Supercond. Sci. Technol. 16, 71 (2002)] to account for in-plane magnetic fields caused by the bending of the applied magnetic field due to the demagnetising effect. After testing on magneto-optical images of a high quality YBa2Cu3O7 superconducting thin film, we show that the procedure employed is effective.
Octahedral tilt independent magnetism in confined GdTiO3 films
Authors: Need R. F. , Isaac B. J. , Kirby B. J. , Borchers J. A. , Stemmer S. , Wilson Stephen D.
Published: March 2018

Low temperature polarized neutron reflectometry measurements are presented, exploring the evolution of ferrimagnetism in thin GdTiO3 films embedded within a SrTiO3 matrix. In GdTiO3 films thinner than ∼4 nm, the TiO6 octahedral tilts endemic to GdTiO3 coherently relax toward the undistorted, cubic phase of SrTiO3. Our measurements indicate that the ferrimagnetic state within the GdTiO3 layers survives as these TiO6 octahedral tilts are suppressed. Furthermore, our data suggest that layers of suppressed magnetization (i.e., magnetic dead layers) develop within the GdTiO3 layer at each GdTiO3/SrTiO3 interface and explain the apparent magnetization suppression observed in thin GdTiO3 films when using volume-averaged techniques. Our data show that the low temperature magnetic moment inherent to the core GdTiO3 layers is only weakly impacted as the octahedral tilt angles are suppressed by more than 50% and the t2g bandwidth is dramatically renormalized.
Orientational dynamics in a room temperature ionic liquid: Are angular jumps predominant?
Authors: Das Suman , Mukherjee Biswaroop , Biswas Ranjit
Published: March 2018

Reorientational dynamics of the constituent ions in a room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), are explored via molecular dynamics simulations, and several features of orientation dynamics are summarized. The anion, [PF6]−, not only exhibits a higher propensity to orientation jumps than the cation, [BMIM]+ but also accesses a wider jump angle distribution and larger peak-angle. Jump and waiting time distributions for both the ions depict power-law dependences, suggesting temporally heterogeneous dynamics for the medium. This heterogeneity feature is further highlighted by the finding that the simulated first rank (ℓ = 1) and second rank (ℓ = 2) average reorientational correlation times reflect a severe break-down of Debye’s ℓ(ℓ + 1) law for orientational diffusion in an isotropic homogeneous medium. Simulated average H-bond lifetime resides between the mean orientation jump and waiting times, while the structural H-bond relaxation suggests, as in normal liquids, a pronounced presence of translational motion of the partnering ions. Average simulated jump trajectories reveal a strong rotation-translation coupling and indicate relatively larger changes in spatial and angular arrangements for the anion during an orientation jump. In fact, a closer inspection of all these results points toward more heterogeneous dynamics for [PF6]− than [BMIM]+. This is a new observation and may simply be linked to the ion-size. However, such a generalization warrants further study.
Water-assisted growth of graphene-carbon nanotube hybrids in plasma
Authors: Tewari Aarti , Ghosh Santanu , Srivastava Pankaj
Published: March 2018

The enhanced growth of graphene-carbon nanotube (CNT) hybrids in a hydrocarbon and hydrogen plasma assisted by water is numerically formulated. The catalyst activity and agglomeration of catalyst particles are the rate determining factors in the growth of hybrids and their constituents, i.e., the CNT and graphene. The water vapor concentration is varied to investigate its effect on the growth process. The enhanced catalyst activity on account of oxidation by hydroxyl ions of water to impede the agglomeration of catalyst particles and the removal of amorphous carbon through etching by hydrogen ions of water are seen to be the main driving forces behind the many fold increase in the dimensions of constituent nanostructures and the hybrids with water vapor concentration. Importantly, beyond a certain specific water vapor concentration, the growth rates dropped due to active oxidation of the catalyst particle.
Electronic structure of ZrX2 (X = Se, Te)
Authors: Shkvarin A. S. , Merentsov A. I. , Shkvarina E. G. , Yarmoshenko Yu. M. , Píš I. , Nappini S. , Titov A. N.
Published: March 2018

The electronic structure of the ZrX2 (X = Se, Te) compounds has been studied using photoelectron, resonant photoelectron and X-ray absorption spectroscopy, theoretical calculations of the X-ray absorption spectra, and density of electronic states. It was found that the absorption spectra and valence band spectra are influenced by the chalcogen type. The results of the multiplet calculation of the Zr4+ atom show that the change in the splitting in the crystal field, which is described by the 10Dq parameter, is due to the change in the ratio of covalent and ionic contributions to the chemical bond. The resonance band near the Fermi level in the valence band spectra is observed for ZrTe2 in the Zr 3p-4d resonant excitation mode. The extent of photon energy indicates the charge localization on the Zr atom. Similar resonance band for ZrSe2 is absent; it indicates the presence of a gap at the Fermi level.
Atomic characterization of nano-facet nitridation at SiC (11¯00) surface
Authors: Mori Daisuke , Fujita Yoshiki , Hirose Takayuki , Murata Koichi , Tsuchida Hidekazu , Matsui Fumihiko
Published: March 2018

Nitridation effectively reduces the density of defects at SiO2/SiC interfaces. The SiC (11¯00) face, which appears at the nano-trench structure on the (0001) and (0001¯) surfaces, is composed of Si- and C-facets. To understand the nitridation mechanism of this face, we investigate the atomic arrangement of N at SiC (11¯00) surface with high temperature annealing in N2 ambient using x-ray photoelectron spectroscopy (XPS) and x-ray photoelectron diffraction (XPD). The N 1s spectrum indicates that N atoms cover about 5/6 of the monolayer and are bonded to Si atoms. The N 1s XPD pattern significantly differs from bulk Si 2p and the C 1s patterns, suggesting that the majority of N atoms occupy C sites at the topmost layer of the 4H-SiC substrate. Based on simulations of the N 1s spectrum and XPD pattern, we propose a local structure where N atoms replace C atoms at four different sites of the SiC (11¯00) surface and bond to three Si atoms.
Detection of viability of micro-algae cells by optofluidic hologram pattern
Authors: Wang Junsheng , Yu Xiaomei , Wang Yanjuan , Pan Xinxiang , Li Dongqing
Published: March 2018

A rapid detection of micro-algae activity is critical for analysis of ship ballast water. A new method for detecting micro-algae activity based on lens-free optofluidic holographic imaging is presented in this paper. A compact lens-free optofluidic holographic imaging device was developed. This device is mainly composed of a light source, a small through-hole, a light propagation module, a microfluidic chip, and an image acquisition and processing module. The excited light from the light source passes through a small hole to reach the surface of the micro-algae cells in the microfluidic chip, and a holographic image is formed by the diffraction light of surface of micro-algae cells. The relation between the characteristics in the hologram pattern and the activity of micro-algae cells was investigated by using this device. The characteristics of the hologram pattern were extracted to represent the activity of micro-algae cells. To demonstrate the accuracy of the presented method and device, four species of micro-algae cells were employed as the test samples and the comparison experiments between the alive and dead cells of four species of micro-algae were conducted. The results show that the developed method and device can determine live/dead microalgae cells accurately.
Cylindrical and spherical solitary waves in an electron-acoustic plasma with vortex electron distribution
Authors: Demiray Hilmi , El-Zahar Essam R.
Published: March 2018

We consider the nonlinear propagation of electron-acoustic waves in a plasma composed of a cold electron fluid, hot electrons obeying a trapped/vortex-like distribution, and stationary ions. The basic nonlinear equations of the above described plasma are re-examined in the cylindrical (spherical) coordinates by employing the reductive perturbation technique. The modified cylindrical (spherical) KdV equation with fractional power nonlinearity is obtained as the evolution equation. Due to the nature of nonlinearity, this evolution equation cannot be reduced to the conventional KdV equation. A new family of closed form analytical approximate solution to the evolution equation and a comparison with numerical solution are presented and the results are depicted in some 2D and 3D figures. The results reveal that both solutions are in good agreement and the method can be used to obtain a new progressive wave solution for such evolution equations. Moreover, the resulting closed form analytical solution allows us to carry out a parametric study to investigate the effect of the physical parameters on the solution behavior of the modified cylindrical (spherical) KdV equation.
Generation of microwave orbital angular momentum states using hemispherical dielectric resonator antenna
Authors: Ren Jian , Leung Kwok Wa
Published: March 2018

A hemispherical dielectric resonator antenna (DRA) generating two orbital angular momentum (OAM) states of l = +1 and  −1 is studied theoretically and experimentally. The DRA is fed with two orthogonal signals, exciting two degenerate higher-order TE221 modes that generate the two OAM states. It was simulated with full-wave simulation software to verify the design method. A prototype operating in the microwave band (5.8 GHz) was fabricated and measured. Its S-parameters, intensity profile, and phase pattern are simulated, and the results are compared with measurements. Also, its far-field radiation pattern, realized antenna gain, and total antenna efficiency are shown for a complete study of the antenna.
CMOS compatible W/CoFeB/MgO spin Hall nano-oscillators with wide frequency tunability
Authors: Zahedinejad M. , Mazraati H. , Fulara H. , Yue J. , Jiang S. , Awad A. A. , Åkerman J.
Published: March 2018

We demonstrate low-operational-current W/Co20Fe60B20/MgO spin Hall nano-oscillators (SHNOs) on highly resistive silicon (HiR-Si) substrates. Thanks to a record high spin Hall angle of the β-phase W (θSH = −0.53), a very low threshold current density of 3.3 × 107 A/cm2 can be achieved. Together with their very wide frequency tunability (7–28 GHz), promoted by a moderate perpendicular magnetic anisotropy, HiR-Si/W/CoFeB based SHNOs are potential candidates for wide-band microwave signal generation. Their CMOS compatibility offers a promising route towards the integration of spintronic microwave devices with other on-chip semiconductor microwave components.
Estimation of sensing characteristics for refractory nitrides based gain assisted core-shell plasmonic nanoparticles
Authors: Shishodia Manmohan Singh , Pathania Pankaj
Published: March 2018

Refractory transition metal nitrides such as zirconium nitride (ZrN), hafnium nitride (HfN) and titanium nitride (TiN) have emerged as viable alternatives to coinage metals based plasmonic materials, e.g., gold (Au) and silver (Ag). The present work assesses the suitability of gain assisted ZrN-, HfN- and TiN-based conventional core-shell nanoparticles (CCSNPs) and multilayered core-shell nanoparticles (MCSNPs) for refractive index sensing. We report that the optical gain incorporation in the dielectric layer leads to multifold enhancement of the scattering efficiency (Qsca), substantial reduction of the spectral full width at half maximum, and a higher figure of merit (FOM). In comparison with CCSNPs, the MCSNP system exhibits superior sensing characteristics such as higher FOM, ∼ 45% reduction in the critical optical gain, response shift towards the biological window, and higher degree of tunability. Inherent biocompatibility, growth compatibility, chemical stability and flexible spectral tuning of refractory nitrides augmented by superior sensing properties in the present work may pave the way for refractory nitrides based low cost sensing.
Interstate vibronic coupling constants between electronic excited states for complex molecules
Authors: Fumanal Maria , Plasser Felix , Mai Sebastian , Daniel Chantal , Gindensperger Etienne
Published: March 2018

In the construction of diabatic vibronic Hamiltonians for quantum dynamics in the excited-state manifold of molecules, the coupling constants are often extracted solely from information on the excited-state energies. Here, a new protocol is applied to get access to the interstate vibronic coupling constants at the time-dependent density functional theory level through the overlap integrals between excited-state adiabatic auxiliary wavefunctions. We discuss the advantages of such method and its potential for future applications to address complex systems, in particular, those where multiple electronic states are energetically closely lying and interact. We apply the protocol to the study of prototype rhenium carbonyl complexes [Re(CO)3(N,N)(L)]n+ for which non-adiabatic quantum dynamics within the linear vibronic coupling model and including spin-orbit coupling have been reported recently.
Heterodyne transverse velocimetry for pressure-shear plate impact experiments
Authors: Kettenbeil Christian , Mello Michael , Bischann Moriah , Ravichandran Guruswami
Published: March 2018

Pressure-shear plate impact experiments have traditionally relied on free space beam interferometers to measure transverse and normal particle velocities at the rear surface of the target plate. Here, we present two different interferometry schemes that leverage heterodyne techniques, which enable the simultaneous measurement of normal and transverse velocities using short-time Fourier transforms. Both techniques rely on diffracted 1st order beams that are generated by a specular, metallic grating deposited on the rear surface of the target plate. The diffracted beam photonic Doppler velocimetry technique interferes each 1st order beam with a reference of slightly higher wavelength to create a constant carrier frequency at zero particle velocity. The second technique interferes the 1st order beams with each other and employs an acousto-optic frequency shifter on the +1st order beam to create a heterodyne transverse velocimeter. For both interferometer techniques, the 0th order beam is interfered in a heterodyne photonic Doppler velocimetry arrangement to obtain a measurement of the normal particle velocity. An overview of both configurations is presented along with a derivation of the interferometer sensitivities to transverse and normal particle velocities as well as design guidelines for the optical system. Results from normal impact experiments conducted on Y-cut quartz are presented as the experimental validation of the two proposed techniques.
Multipactor susceptibility on a dielectric with two carrier frequencies
Authors: Iqbal Asif , Verboncoeur John , Zhang Peng
Published: March 2018

This work investigates multipactor discharge on a single dielectric surface with two carrier frequencies of an rf electric field. We use Monte Carlo simulations and analytical calculations to obtain susceptibility diagrams in terms of the rf electric field and normal electric field due to the residual charge on the dielectric. It is found that in contrast to the single frequency case, in general, the presence of a second carrier frequency of the rf electric field increases the threshold of the magnitude of the rf electric field to initiate multipactor. The effects of the relative strength and phase, and the frequency separation of the two carrier frequencies are examined. The conditions to minimize mulitpactor are derived.
Growth of HfN thin films by reactive high power impulse magnetron sputtering
Authors: Thorsteinsson D. Ö. , Gudmundsson J. T.
Published: March 2018

Thin hafnium nitride films were grown on SiO2 by reactive high power impulse magnetron sputtering (HiPIMS) and reactive direct current magnetron sputtering (dcMS). The conditions during growth were kept similar and the film properties were compared as growth temperature, nitrogen flow rate, and in the case of HiPIMS, duty cycle were independently varied. The films were characterized with grazing incidence X-ray diffraction (GIXRD), X-ray reflection (XRR) and X-ray stress analysis (XSA). HiPIMS growth had a lower growth rate for all grown films, but the films surfaces were smoother. The film density of HiPIMS deposited films grown at low duty cycle was comparable to dcMS grown films. Increasing the duty cycle increased the density of the HiPIMS grown films almost to the bulk density of HfN as well as increasing the growth rate, while the surface roughness did not change significantly. The HiPIMS grown films had large compressive stress while the dcMS grown films had some tensile stress. The dcMS grown films exhibit larger grains than HiPIMS grown films. The grain size of HiPIMS grown films decreases with increasing nitrogen flow rate, while the dcMS grain size increased with increasing nitrogen flow rate. This work shows that duty cycle during HiPIMS growth of HfN films has a significant effect on the film density and growth rate while other film properties seem mostly unaffected.
A dipolar structure in the heat-flux dependent thermoelasticity
Authors: Marin Marin , Vlase Sorin , Carstea Claudia
Published: March 2018

Our study is concerned with the mixed initial-boundary value problem for a dipolar body in the context of a heat-flux dependent theory for the dipolar thermoelastic bodies. We take into account a set of independent constitutive variables including the heat flux vector. Also, the set of basic equations which govern the behavior of such a body is completed by including an equation of evolution for the components of this vector. The uniqueness result, regarding the solution of the mixed problem, which concludes our study assures the consistency of the constructed theory.