bluuebunny/crossref_metadata_2025 huggingface dataset:
Derivation and analysis of coupled PDEs on manifolds with high dimensionality gap arising from topological model reduction
Authors: Laurino Federica , Zunino Paolo
Published: June 2019

Multiscale methods based on coupled partial differential equations defined on bulk and embedded manifolds are still poorly explored from the theoretical standpoint, although they are successfully used in applications, such as microcirculation and flow in perforated subsurface reservoirs. This work aims at shedding light on some theoretical aspects of a multiscale method consisting of coupled partial differential equations defined on one-dimensional domains embedded into three-dimensional ones. Mathematical issues arise because the dimensionality gap between the bulk and the inclusions is larger than one, that is the high dimensionality gap case. First, we show that such model derives from a system of fully three-dimensional equations, by the application of a topological model reduction approach. Secondly, we rigorously analyze the problem, showing that the averaging operators applied for the model reduction introduce a regularization effect that resolves the issues due to the singularity of solutions and to the ill-posedness of restriction operators. Then, we exploit the structure of the model reduction technique to analyze the modeling error. This study confirms that for infinitesimally small inclusions, the modeling error vanishes. Finally, we discretize the problem by means of the finite element method and we analyze the approximation and the model error by means of numerical experiments.
Convergence of a finite volume scheme for the compressible Navier–Stokes system
Authors: Feireisl Eduard , Lukáčová-Medvid’ová Mária , Mizerová Hana , She Bangwei
Published: June 2019

We study convergence of a finite volume scheme for the compressible (barotropic) Navier–Stokes system. First we prove the energy stability and consistency of the scheme and show that the numerical solutions generate a dissipative measure-valued solution of the system. Then by the dissipative measure-valued-strong uniqueness principle, we conclude the convergence of the numerical solution to the strong solution as long as the latter exists. Numerical experiments for standard benchmark tests support our theoretical results.
Collaboration of community hospital endosonographers improves diagnostic yield of endoscopic ultrasonography guided tissue acquisition of solid pancreatic lesions
Authors: Quispel Rutger , van Driel Lydi M.J.W. , Honkoop Pieter , Hadithi Mohamad , Anten Marie-Paule , Smedts Frank , Kerkmeer Margreet C. , Veldt Bart J. , Bruno Marco J. ,   On behalf of the Dutch, Rotterdam Regional, QUality in EndoSonography Team (QUEST)
Published: June 2019

Background and study aims Endoscopic ultrasound (EUS)-guided tissue acquisition (TA) is the method of choice for establishing a pathological diagnosis of solid pancreatic lesions. Data on quality and yield of EUS-guided TA performed in community hospitals are lacking. A study was performed to determine and improve the diagnostic yield of EUS-guided TA in a group of community hospitals.

Methods Following analysis of the last 20 EUS-guided TA procedures of solid pancreatic lesions performed in each of four community hospitals, a collaborative EUS interest group was formed and a prospective registry was started. During meetings of the interest group, feedback on results per center were provided and strategies for improvement were discussed.

Results In the BEFORE team formation cohort, 80 procedures were performed in 66 patients. In the AFTER team formation cohort, 133 procedures were performed in 125 patients. After team formation, the rate of adequate sample increased from 80 % (95 %CI [0.7 – 0.9]) to 95 % (95 %CI [0.9 – 1.0]) , diagnostic yield of malignancy improved from 28 % (95 %CI [0.2 – 0.4]) to 64 % (95 % CI [0.6 – 0.7]), and sensitivity of malignancy improved from 63 % (95 %CI [0.4 – 0.8]) to 84 % (95 %CI [0.8 – 0.9]). Multivariate regression analysis revealed team formation to be the only variable significantly associated with an increased rate of adequate sample.

Conclusions Formation of a regional EUS interest group with regular feedback on results per center, and discussions on methods and techniques used, significantly improved the outcome of EUS-guided TA procedures in patients with solid pancreatic lesions in community hospitals.
Mechanochemically Gated Photoswitching: Expanding the Scope of Polymer Mechanochromism
Authors: Barber Ross W. , McFadden Molly E. , Hu Xiaoran , Robb Maxwell J.
Published: June 2019

Mechanophores are molecules that undergo productive, covalent chemical transformations in response to mechanical force. Over the last decade, a variety of mechanochromic mechanophores have been developed that enable the direct visualization of stress in polymers and polymeric materials through changes in color and chemiluminescence. The recent introduction of mechanochemically gated photoswitching extends the repertoire of polymer mechanochromism by decoupling the mechanical activation from the visible response, enabling the mechanical history of polymers to be recorded and read on-demand using light. Here, we discuss advances in mechanochromic mechanophores and present our design of a cyclopentadiene–maleimide Diels–Alder adduct that undergoes a force-induced retro-[4+2] cycloaddition reaction to reveal a latent diarylethene photoswitch. Following mechanical activation, UV light converts the colorless diarylethene molecule into the colored isomer via a 6π-electrocyclic ring-closing reaction. Mechanically gated photoswitching expands on the fruitful developments in mechanochromic polymers and provides a promising platform for further innovation in materials applications including stress sensing, patterning, and information storage.

1 Introduction to Polymer Mechanochemistry

2 Mechanochromic Reactions for Stress Sensing

3 Regiochemical Effects on Mechanophore Activation

4 Mechanochemically Gated Photoswitching

5 Conclusions
Referentenentwurf: MDK soll unabhängiger von Kassen werden
Authors: Doelfs Guntram
Published: June 2019

Seit Jahren streiten Krankenkassen und Kliniken erbittert um die Abrechnungsprüfungen des Medizinischen Dienstes der Krankenkassen. Nun hat Jens Spahn einen Gesetzentwurf zur Reform des MDK vorgelegt – und erntet dafür breites Lob. Der Grund: Der Entwurf kommt geschickt beiden Seiten entgegen.
Memristor effect in GeO[SiO2] and GeO[SiO] solid alloys films
Authors: Volodin V. A. , Kamaev G. N. , Gritsenko V. A. , Gismatulin A. A. , Chin A. , Vergnat M.
Published: June 2019

The p-Si(or n-Si)/GeO[SiO2] (or GeO[SiO])/indium-tin-oxide (ITO) structures were fabricated by simultaneous evaporation of GeO2 and SiO2 (or SiO) powders in high vacuum and further deposition of ITO contacts using the magnetron sputtering technique. The structural properties of the GeO[SiO2] and GeO[SiO] films were studied using FTIR and Raman spectroscopy. According to Raman data, the GeO[SiO] films deposited at a temperature of 100 °C contain amorphous Ge clusters. Their current-voltage characteristics were measured in the air atmosphere, and resistive switching (memristor effect) was observed in structures without a preliminary forming procedure. The Shklovskii-Efros percolation model gives a consistent explanation for the charge transport in the high-resistive state and the low-resistive state of memristors based on GeO[SiO2] or GeO[SiO] films.
Nanotesla sensitivity magnetic field sensing using a compact diamond nitrogen-vacancy magnetometer
Authors: Webb James L. , Clement Joshua D. , Troise Luca , Ahmadi Sepehr , Johansen Gustav Juhl , Huck Alexander , Andersen Ulrik L.
Published: June 2019

Solid state sensors utilizing diamond nitrogen-vacancy (NV) centers are a promising sensing platform that can provide high sensitivity and spatial resolution at high precision. Such sensors have been realized in bulky laboratory-based forms; however, practical applications demand a miniaturized, portable sensor that can function in a wide range of environmental conditions. Here, we demonstrate such a diamond NV magnetic field sensor. The sensor head fits inside a 11×7×7 cm3 3D-printed box and exhibits sub-10 nT/Hz sensitivity over a 125 Hz bandwidth. We achieve efficient fluorescence collection using an optical filter and diode in contact with the diamond, which is cut at the Brewster angle to maximize the coupling of 532 nm pump light. We discuss the potential of this flexible approach to achieve sub-nT/Hz shot noise limited sensitivity suitable for detection of a wide range of low-level magnetic fields, particularly those from electrical power systems and from biological sources.
Simultaneous Raman and pyrometric temperature measurements in shock-wave-compressed toluene
Authors: Capelle G. A. , Mance J. G. , Larson E. D. , La Lone B. M. , Stevens G. D. , Turley W. D. , Veeser L. R.
Published: June 2019

We fielded experiments to compare temperatures measured simultaneously by pyrometry and Raman spectroscopy in toluene shocked to 9 GPa. A 0.5 mm thick toluene sample was compressed between sapphire windows by plate impact from a gas gun. As the shock wave reverberated between the windows, the pressure increased stepwise to about 9 GPa. While the sample was near its peak pressure, we measured the Raman spectrum and determined temperature from the ratio of the Stokes and anti-Stokes intensities. Simultaneously, we measured the sample thermal radiance from the C-H vibration bands that occur between 3.2 and 3.6 μm to determine temperature pyrometrically. The pyrometer used a biased indium antimonide detector paired with a custom transimpedance amplifier, a system capable of temperature measurements as low as about 400 K. The Raman measurements gave a temperature of 530 ± 25 K in the bulk volume of toluene. Pyrometry gave a temperature of 496 + 15/−20 K, which is in reasonable agreement with the Raman measurement. Comparisons of this type are necessary to validate pyrometry as a temperature diagnostic in dynamic experiments.
Computer modeling of single-layer nanocluster formation in a thin SiO2 layer buried in Si by ion mixing and thermal phase decomposition
Authors: Prüfer Thomas , Möller Wolfhard , Heinig Karl-Heinz , Wolf Daniel , Engelmann Hans-Jürgen , Xu Xiaomo , von Borany Johannes
Published: June 2019

A single sheet of Si nanoclusters with an average diameter of about 2 nm has been formed in a 30 nm Si/7 nm SiO2/Si layer stack by 50 and 60 keV Si+ ion-beam mixing at room temperature and fluences between 8.5 ⋅ 1015 and 2.6 ⋅ 1016 ions/cm2 and by subsequent thermal annealing at a temperature above 1000 °C. Computer modeling of the process is accomplished by TRIDYN dynamic ballistic simulation of ion mixing and subsequent lattice kinetic Monte Carlo simulation of the phase decomposition of substoichiometric silicon oxide into Si nanoclusters in a SiO2 matrix. The simulation algorithms are briefly described with special emphasis on the choice of governing parameters for the present system. In comparison to the experimental results, it is concluded that the predicted ion mixing profiles overestimate the interface broadening. This discrepancy is attributed to the neglect of chemical driving forces in connection with thermal-spike induced diffusion, which tends to reconstitute the Si/SiO2 interfaces. With a corresponding correction and a suitable number of Monte Carlo steps, the experimentally obtained areal densities and average diameters of the nanoclusters are successfully reproduced.
Electronic and magnetic properties of the transition-metal absorbed blue-phosphorus/MoS2 heterostructure: A first-principles investigation
Authors: Bian Hongying , Duan Haiming , Li Jialin , Chen Fengjuan , Cao Biaobing , Long Mengqiu
Published: June 2019

Based on the first principle of calculation, we constructed an ideal van der Waals (vdW) heterostructures by placing BlueP above MoS2 monolayer. We have determined the most stability structure and calculated its electronic properties. Importantly, we studied the effects of the 3d transition metal (TM) atoms, such as Sc, Ti, V, Cr, Mn, adsorbed in the interlayer of BlueP/MoS2 vdW heterostructure, and our calculated band structures show that when the heterostructure adsorbs TM atoms, it can be transitioned from semiconductor to spin-polarized metals. Moreover, the spin-up and spin-down states are spin-split on different k-points, and the spin separated spatially behavior can also be observed. Our results suggest that the BlueP/MoS2 vdW heterostructure with TM atom adsorption would be a candidate material for application in nanoelectronics and spintronics devices in future.
A magnetic bottle time-of-flight electron spectrometer suitable for continuous ionization sources
Authors: Strobel Christoph , Gantefoer Gerd , Bodi Andras , Hemberger Patrick
Published: June 2019

We present a newly developed magnetic-bottle time-of-flight electron spectrometer suitable for continuous or quasicontinuous photoionization sources such as synchrotrons. A strong magnetic field collects almost all photoelectrons from a well-defined ionization volume and quantitatively suppresses background electrons which originate outside of this interaction region. Although it is a pulsed instrument, a relatively high duty cycle is achieved by storing the photoelectrons generated between two cycles in an electromagnetic trap. This makes the new instrument suitable for experiments with very low sample densities. Another advantage is the high energy resolution, 50 meV in the first version of the spectrometer described here, which simply depends on the length of the time-of-flight instrument.
Effect of In composition on electrical performance of AlInGaN/GaN-based metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) on Si
Authors: Biswas Debaleen , Fujita Hirotaka , Torii Naoki , Egawa Takashi
Published: June 2019

Al x In y Ga ( 1 − x − y ) N / GaN heterostructures were grown on 4-in. p-type Si wafers to investigate the effect of In composition in the quaternary nitride layer on the electrical performance of Al2O3/AlInGaN/GaN-based normally-ON metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs). From the comparative study of the electrical measurements, it was observed that the transport properties of the devices were relatively poor in the presence of higher In composition in the quaternary-N layer. The deterioration of the electrical characteristics of MIS-HEMTs originated from the formation of deep pits on the AlInGaN epilayer surface caused by the segregation of In atoms during epitaxial growth. However, the formation of such pits was reduced for the quaternary epilayer with lower In content and exhibited better transport performance. A maximum current density (Id,max) of 780 mA/mm with a specific ON-resistance of 0.71mΩcm2 was observed for the device fabricated on the wafer with an In composition of 9% in the AlInGaN epilayer. We have achieved a high breakdown voltage of 793 V with a device with the gate-to-drain distance (Lgd) of 20μm under the off-state condition.
Shock wave in a long-air-gap leader discharge
Authors: Cui Yingzhe , Zhuang Chijie , Zeng Rong , Zhou Xuan
Published: June 2019

We report the shock wave phenomenon in an air-gap leader discharge observed using an interferometer. The continuous temporal evolution of the shock wave and plasma channel is recorded and reproduced with a thermohydrodynamic model based on the measured current, providing a prediction of the pressure pulses of the shock wave. The weak shock wave propagates at nearly the speed of sound, and the simulation results for the shock wave front positions and the plasma channel radius are consistent with experimental measurements. Experimental observations and numerical comparisons show that continuous energy injection results in a temporary overpressure process in the plasma channel and generates the shock wave. The pressure at the shock front falls rapidly and decays with propagation of the wave. In the weak shock region, the pressure wave decays as P∝R−3/4. The wave propagation predicted using the thermohydrodynamic model is compared with propagations predicted using the Vlases and Jones models, and we find that a measurement of the shock wave propagation trajectory gives an estimate of the energy injected to the leader channel during a discharge.
Underwater spiders inspire bubble study that could help industry trap waste gas
Authors: Dooley Phil
Published: June 2019

Hydrophobic fibers that spiders employ to trap air so they can breathe underwater could help trap and remove gas bubbles in liquids in industrial situations.
Understanding attitudes on new technologies to manage invasive species
Authors: Kirk Nick , Kannemeyer Robyn , Greenaway Alison , MacDonald Edy , Stronge Dean
Published: June 2019

Invasive animal species threaten global biodiversity. In New Zealand invasive species threaten iconic native species, and scientists are seeking approval to research new technologies that might be capable of eradicating these invasive species. The aim of this research was to understand what New Zealanders with an interest in pest control consider to be the main risks and benefits of introducing new technologies to manage invasive species. We invited key informants to participate in the focus groups, selecting people with knowledge and experience of pest control issues in New Zealand. Data were collected from seven focus groups held in three locations across New Zealand. A thematic analysis of the data was then conducted in which three key themes emerged: concern about the risk of unintended consequences, the benefits of landscape-scale technologies, and New Zealand being an early adopter of new technologies. The focus groups articulated a variety of benefits from introducing new technologies – such as replacing dangerous poisons with non-toxic alternatives – but it was the risks of the new technologies that dominated the discussions. Given these results, we recommend an education and communication strategy focussed on social learning, in conjunction with a codesigned decision-making process, to help establish social licence for the application of potentially controversial technologies.
Region-specific and activity-dependent regulation of SVZ neurogenesis and recovery after stroke
Authors: Liang Huixuan , Zhao Handi , Gleichman Amy , Machnicki Michal , Telang Sagar , Tang Sydney , Rshtouni Mary , Ruddell Jack , Carmichael S. Thomas
Published: June 2019

Significance

Recovery after stroke involves remodeling in brain tissue adjacent to the stroke site. In this remodeling, neurogenesis after stroke involves the formation of new neurons. The role of neurogenesis in stroke recovery and the role of brain and behavioral activity in this process remain undefined. Using orthogonal transgenic mouse tracing and rabies virus approaches, we demonstrate that brain regions unexpectedly compete for new neurons after stroke and that the behavioral or cellular activity establishes this competition. These new neurons synaptically integrate into cortex, and this integration is necessary for poststroke recovery.
Social evolution leads to persistent corruption
Authors: Lee Joung-Hun , Iwasa Yoh , Dieckmann Ulf , Sigmund Karl
Published: June 2019

Significance

Corruption is widely perceived as a major problem. Bribery of judicial institutions undermines the trust needed for joint efforts and economic investments. Transparency can reestablish trust, but at the cost of constant supervision of the institutions. Reducing such vigilance is advantageous in the short term. In the long run, it leads to more cheating and less cooperation. This can create cyclic outbursts of corruption or maintain corruption at a stable level.
Supperordinner?
Authors: Jankowski Bridget L. , Tagliamonte Sali A.
Published: June 2019

The English words for daily meals constitute a complex lexical variable conditioned by social and linguistic factors. Comparative sociolinguistic analysis of 884 speakers from more than a dozen locations in Ontario, Canada reveals a synchronic system with social correlates that are reflexes of the British and American founder populations of the province. Toronto and Loyalist settlements in southern Ontario use the highest rates ofdinnerwhile northerners with European and Scots-Irish roots usesupper. Dinneris taking over as the dominant form among younger speakers, exposing a cascade pattern (Trudgill 1972;Labov 2007) that is consistent with sociolinguistic typology (Trudgill 2011).
Neoliberal feminism in contemporary South Korean popular music
Authors: Kim Gooyong
Published: June 2019

This paper examines how South Korean popular music (K-pop) promotes neoliberal feminism by a
discourse of resilience. In a therapeutic narrative of overcoming obstacles and achieving goals, K-pop videos
deliver a hegemonic message that individuals have to be responsible for their success and well-being rather
than blaming external, institutional conditions. While ostensibly promoting female empowerment, the videos
update and reinforce patriarchal gender norms and expectations. To substantiate this point, I analyze music
videos of the most successful K-pop group, Girls’ Generation’s “Into the New World” (2007) and “All Night”
(2017) to investigate how they promote resilience discourse along with neoliberal positive psychology as a
hegemonic ideal of female subjectivity.
A development of novel Ni–P coating on anodised aluminium alloys for military industries applications in artificial sea water
Authors: Abdel-Gawad Soha A. , Osman Walid M. , Fekry Amany M.
Published: June 2019

The corrosion behaviour and characterisation properties of a novel Ni–P coating on anodised aluminium alloys were inspected by utilising a salt spray technique and a polarisation system in artificial sea water. The Ni–P layer on anodised coating progression was achieved on aluminium alloys such as Al2014, Al6061 and Al7075, which are utilised in military industries. The outcomes revealed that the coating layer is contingent on the alloy type and coating settings like current density, temperature and time. Also, film thickness and hardness of aluminium alloys have been considered. The corrosion rate was established to be dependent on the alloying element such as copper. The deterioration rates of Al7075 and Al6061 were diminished by about one order of magnitude; however, for Al2014, it was amplified by an equivalent order of magnitude.
Domain walls and their interactions in a two-component Bose–Einstein condensate*
Authors: Meng Ling-Zheng , Qin Yan-Hong , Zhao Li-Chen , Yang Zhan-Ying
Published: June 2019

We investigate domain wall excitations in a two-component Bose–Einstein condensate with two-body interactions and pair-transition effects. It is shown that domain wall excitations can be described exactly by kink and anti-kink excitations in each component. The domain wall solutions are given analytically, which exist with different conditions compared with the domain wall reported before. Bubble-droplet structure can be also obtained from the fundamental domain wall, and their interactions are investigated analytically. Especially, domain wall interactions demonstrate some striking particle transition dynamics. These striking transition effects make the domain wall admit quite different collision behavior, in contrast to the collision between solitons or other nonlinear waves. The collisions between kinks induce some phase shift, which makes the domain wall change greatly. Their collisions can be elastic or inelastic with proper combination of fundamental domain walls. These characters can be used to manipulate one domain wall by interacting with other ones.
Non-adiabatic quantum dynamical studies of

Na
(
3
p
)
+
HD
(
ν
=
1
,

j
=
0
)
→
NaH

/

NaD
+
D

/

H

reaction*
Authors: Wen Yue-Pei , Buren Bayaer , Chen Mao-Du
Published: June 2019

Non-adiabatic dynamical calculations are carried out for the

Na
(
3
p
)
+
HD
(
ν
=
1
,

j
=
0
)
→
NaH

/

NaD
+
D

/

H

reaction on the diabatic potential energy surfaces of Wang et al. (Sci. Rep. 2018, 8, 17960) by using the time-dependent wave packet method. The state-to-state integral cross sections and differential cross sections of two reaction channels (NaH/NaD+D/H) are calculated for collision energy up to 0.4 eV. The cross section branching ratio indicates that the dominant reaction channel changes from NaD+H to NaH+D when the collision energy is larger than 0.227 eV. The products from two reaction channels both prefer to form in vibrationally cold but rotationally hot states, and they both tend to forward scattering.
Analysis of third and one-third harmonic generation in lossy waveguides*
Authors: Zhang Jianyu , Sun Yunxu , Song Qinghai
Published: June 2019

A comprehensive study on the requirements for the highly efficient third harmonic generation (THG) and its inverse process, one-third harmonic generation (OTHG), in lossy waveguides is proposed. The field intensity restrictions for both THG and OTHG caused by loss are demonstrated. The effective relative phase ranges, supporting the positive growth of signal fields of THG and OTHG are shrunken by the loss. Furthermore, it turns out that the effective relative phase ranges depend on the intensities of the interacting fields. At last, a modified definition of coherent length in loss situation, which evaluates the phase matching degree more precisely, is proposed by incorporating the shrunken relative phase range and the nonlinear phase mismatch. These theoretical analysis are valuable for guiding the experimental designs for highly efficient THG and OTHG.
Infrared cooling properties of cordierite*
Authors: Chen Si-Heng , Wang Xiao-Xiong , Nie Guang-Di , Liu Qi , Sui Jin-Xia , Song Chao , Zhu Jian-Wei , Fu Jie , Zhang Jun-Cheng , Yan Xu , Long Yun-Ze
Published: June 2019

Cordierite (Mg2Al4Si5O18) is known for its good thermal shock resistance and it is widely used to improve thermal shock properties of materials. We found that cordierite has good infrared heat dissipation performance. This performance provides an additional means of heat dissipation to assist in the cooling of the metal surface. Spectroscopic tests show that cordierite reflects sunlight in the visible range and emits infrared in the far infrared range, making it potential candidate as an infrared radiative cooling material for daytime use.
Flow characteristics of supersonic gas passing through a circular micro-channel under different inflow conditions*
Authors: Guo Guang-Ming , Luo Qin , Zhu Lin , Bian Yi-Xiang
Published: June 2019

Gas flow in a micro-channel usually has a high Knudsen number. The predominant predictive tool for such a micro-flow is the direct simulation Monte Carlo (DSMC) method, which is used in this paper to investigate primary flow properties of supersonic gas in a circular micro-channel for different inflow conditions, such as free stream at different altitudes, with different incoming Mach numbers, and with different angles of attack. Simulation results indicate that the altitude and free stream incoming Mach number have a significant effect on the whole micro-channel flow field, whereas the angle of attack mainly affects the entrance part of micro-channel flow field. The fundamental mechanism behind the simulation results is also presented. With the increase of altitude, thr free stream would be partly prevented from entering into micro-channel. Meanwhile, the gas flow in micro-channel is decelerated, and the increase in the angle of attack also decelerates the gas flow. In contrast, gas flow in micro-channel is accelerated as free stream incoming Mach number increases. A noteworthy finding is that the rarefaction effects can become very dominant when the free stream incoming Mach number is low. In other words, a free stream with a larger incoming velocity is able to reduce the influence of the rarefaction effects on gas flow in the micro-channel.
Relationship between characteristic lengths and effective Saffman length in colloidal monolayers near a water–oil interface*
Authors: Li Na , Zhang Wei , Chen Wei
Published: June 2019

The hydrodynamic interactions (HIs) in colloidal monolayers are strongly influenced by the boundary conditions and can be directly described in terms of the cross-correlated diffusion of the colloid particles. In this work, we experimentally measured the cross-correlated diffusion in colloidal monolayers near a water–oil interface. The characteristic lengths of the system were obtained by introducing an effective Saffman length. The characteristic lengths of a particle monolayer near a water–oil interface were found to be anisotropic in the longitudinal and transverse directions. From these characteristic lengths, the master curves of cross-correlated diffusion are obtained, which universally describe the HIs near a liquid–liquid interface.
Real-space observation on standing configurations of phenylacetylene on Cu (111) by scanning probe microscopy*
Authors: Qi Jing , Gao Yi-Xuan , Huang Li , Lin Xiao , Dong Jia-Jia , Du Shi-Xuan , Gao Hong-Jun
Published: June 2019

The adsorption configurations of molecules adsorbed on substrates can significantly affect their physical and chemical properties. A standing configuration can be difficult to determine by traditional techniques, such as scanning tunneling microscopy (STM) due to the superposition of electronic states. In this paper, we report the real-space observation of the standing adsorption configuration of phenylacetylene on Cu (111) by non-contact atomic force microscopy (nc-AFM). Deposition of phenylacetylene at 25 K shows featureless bright spots in STM images. Using nc-AFM, the line features representing the C–H and C–C bonds in benzene rings are evident, which implies a standing adsorption configuration. Further density functional theory (DFT) calculations reveal multiple optimized adsorption configurations with phenylacetylene breaking its acetylenic bond and forming C–Cu bond(s) with the underlying copper atoms, and hence stand on the substrate. By comparing the nc-AFM simulations with the experimental observation, we identify the standing adsorption configuration of phenylacetylene on Cu (111). Our work demonstrates an application of combining nc-AFM measurements and DFT calculations to the study of standing molecules on substrates, which enriches our knowledge of the adsorption behaviors of small molecules on solid surfaces at low temperatures.
Magnetotransport properties of graphene layers decorated with colloid quantum dots*
Authors: Zhu Ri-Jia , Huang Yu-Qing , Li Jia-Yu , Kang Ning , Xu Hong-Qi
Published: June 2019

The hybrid graphene-quantum dot devices can potentially be used to tailor the electronic, optical, and chemical properties of graphene. Here, the low temperature electronic transport properties of bilayer graphene decorated with PbS colloid quantum dots (CQDs) have been investigated in the weak or strong magnetic fields. The presence of the CQDs introduces additional scattering potentials that alter the magnetotransport properties of the graphene layers, leading to the observation of a new set of magnetoconductance oscillations near zero magnetic field as well as the high-field quantum Hall regime. The results bring about a new strategy for exploring the quantum interference effects in two-dimensional materials which are sensitive to the surrounding electrostatic environment, and open up a new gateway for exploring the graphene sensing with quantum interference effects.
Neutral excitation and bulk gap of fractional quantum Hall liquids in disk geometry*
Authors: Yang Wu-Qing , Li Qi , Yang Lin-Peng , Hu Zi-Xiang
Published: June 2019

For the numerical simulation of the fractional quantum Hall (FQH) effects on a finite disk, the rotational symmetry is the only symmetry that is used in diagonalizing the Hamiltonian. In this work, we propose a method of using the weak translational symmetry for the center of mass of the many-body system. With this approach, the bulk properties, such as the energy gap and the magneto-roton excitation are consistent with those in the closed manifolds like the sphere and torus. As an application, we consider the FQH phase and its phase transition in the fast rotated dipolar fermions. We thus demonstrate the disk geometry having versatility in analyzing the bulk properties beside the usual edge physics.
Aging mechanism of GaN-based yellow LEDs with V-pits*
Authors: Zhang Tian-Ran , Fang Fang , Wang Xiao-Lan , Zhang Jian-Li , Wu Xiao-Ming , Pan Shuan , Liu Jun-Lin , Jiang Feng-Yi
Published: June 2019

GaN-based yellow light-emitting diodes (LEDs) on Si substrates are aged at a direct current density of 50 A/cm2 for 500 h. After the aging process, it can be found that the LEDs have a stable electrical property but their light output power is decayed by 4.01% at 35 A/cm2. Additionally, the aging mechanism of GaN-based yellow LED is analyzed. It is found that the decay of light output power may be attributed to the following two reasons: one is the increase of Shockley–Rrad–Hall recombination and the other is the change of the transport path of holes via V-pits after aging, which may induce the radiative recombination current to decrease. In this paper, not only the aging mechanism of GaN-based yellow LED is investigated, but also a new possible research direction in LED aging is given.
Crystal structures and sign reversal Hall resistivities in iron-based superconductors Lix(C3H10N2)0.32FeSe

(
0.15
<
x
<
0.4

)*
Authors: Sun Rui-Jin , Jin Shi-Feng , Deng Jun , Hao Mu-Nan , Zhao Lin-Lin , Fan Xiao , Sun Xiao-Ning , Guo Jian-Gang , Gu Lin
Published: June 2019

Heavy electron-doped FeSe-derived materials have attracted attention due to their uncommon electronic structures with only ‘electron pockets’, and they are different from other iron-based superconductors. Here, we report the crystal structures, superconductivities and normal state properties of two new Li-doped FeSe-based materials, i.e., Li0.15(C3H10N2)0.32FeSe (P-4) and Li
x
(C3H10N2)0.32FeSe (P4/nmm,

0.25
<
x
<
0.4

) with superconducting transition temperatures ranging from 40 K to 46 K. The determined crystal structures reveal a coupling between Li concentration and the orientation of 1,3-diaminopropane molecules within the largely expanded FeSe layers. Superconducting fluctuations appear in the resistivity of the two superconductors and are fitted in terms of the quasi two-dimensional (2D) Lawrence–Doniach model. The existence of a crossing point and scaling behavior in the T-dependence of diamagnetic response also suggests that the two superconductors belong to the quasi-2D system. Interestingly, with the increase of temperature, a sign of Hall coefficient (R
H) reversing from negative to positive is observed at ∼185 K in both phases, suggesting that ‘hole pockets’ emerge in these electron-doped FeSe materials. First principle calculations indicate that the increase in FeSe layer distance will lift up a ‘hole band’ associated with

d

x

2

−

y

2

character and increase the hole carriers. Our findings suggest that the increase in two dimensionalities may lead to the sign-reversal Hall resistivity in Li
x
(C3H10N2)0.32FeSe at high temperature.
Critical behavior and magnetocaloric effect in magnetic Weyl semimetal candidate Co2−xZrSn*
Authors: Yu Tianlin , Yu Xiaoyun , Yang En , Sun Chang , Zhang Xiao , Lei Ming
Published: June 2019

We investigate the critical exponents and magnetocaloric effect of Co2−x
ZrSn polycrystal. The Co2−x
ZrSn undergoes a second-order ferromagnetism phase transition around the Curie temperature of T
c ∼280 K. The critical behavior in the vicinity of the magnetic phase transition has been investigated by using modified Arrott plot and Kouvel–Fisher methods. The obtained critical exponents, β, γ, and δ can be well described by the scaling theory. The determined exponents of Co2−x
ZrSn obey the mean-field model with a long-range magnetic interaction. In addition, the maximum magnetic entropy change

−
Δ

S

M

max

of Co2−x
ZrSn is about

0.57

J
·

kg

−
1

·

K

−
1

and the relative cooling power (RCP) is

14.68

J
·

kg

−
1

at 50 kOe (

1

Oe
=
79.5775

A
·

m

−
1

).
Influence of carbon coating on the electrochemical performance of SiO@C/graphite composite anode materials*
Authors: Lu Hao , Wang Junyang , Liu Bonan , Chu Geng , Zhou Ge , Luo Fei , Zheng Jieyun , Yu Xiqian , Li Hong
Published: June 2019

Silicon monoxide (SiO) has been considered as one of the most promising anode materials for next generation high-energy-density Li-ion batteries (LiBs) thanks to its high theoretical capacity. However, the poor intrinsic electronic conductivity and large volume change during lithium intercalation/de-intercalation restrict its practical applications. Fabrication of SiO/C composites is an effective way to overcome these problems. Herein, a series of micro-sized SiO@C/graphite (SiO@C/G) composite anode materials, with designed capacity of

600

mAh
·

g

−
1

, are successfully prepared through a pitch pyrolysis reaction method. The electrochemical performance of SiO@C/G composite anodes with different carbon coating contents of 5 wt%, 10 wt%, 15 wt%, and 35 wt% is investigated. The results show that the SiO@C/G composite with 15-wt% carbon coating content exhibits the best cycle performance, with a high capacity retention of 90.7% at 25 °C and 90.1% at 45 °C after 100 cycles in full cells with LiNi0.5Co0.2Mn0.3O2 as cathodes. The scanning electron microscope (SEM) and electrochemistry impedance spectroscopy (EIS) results suggest that a moderate carbon coating layer can promote the formation of stable SEI film, which is favorable for maintaining good interfacial conductivity and thus enhancing the cycling stability of SiO electrode.
Research on SEE mitigation techniques using back junction and p+ buffer layer in domestic non-DTI SiGe HBTs by TCAD*
Authors: Wei Jia-Nan , He Chao-Hui , Li Pei , Li Yong-Hong
Published: June 2019

In this paper we investigate two techniques for single event effect (SEE) mitigation by using back junction and p+ buffer layer in non-deep trench isolation (DTI) domestic silicon–germanium heterojunction bipolar transistors (SiGe HBTs) based on technology computer aided design (TCAD) simulation. The effectiveness of the two mitigation techniques and the influence of various structure parameters are investigated. Simulation results indicate that the two techniques are more effective in reducing collector charge collection induced by heavy ions striking at positions outside the collector–substrate (C–S) junction where charge collection is dominated by diffusion. By properly adjusting the parameters, charge collection of events outside the C–S junction can be reduced by more than an order of magnitude, while charge collection of events in the device center is halved without affecting the direct current (DC) and alternating current (AC) characteristics of the SiGe HBTs.
Luminescent properties of Tb3+ doped ZrO2 films
Authors: Ramos A.I. , Sanchez M. , Guzmán J. , Torres J.G. , García M. , Rivera T.
Published: June 2019

In the present work luminescence properties of terbium trivalent (Tb3+) doped ZrO2 were studied. Ultrasonic spray pyrolysis (USP) technique was employed to deposit the films. PL emission of the ZrO2:Tb3+ films exhibits emission peaks around 489, 548, 588, and 620 nm corresponding to transitions 5D4→7F6, 5D4→7F5, 5D4 →7F4, and 5D4→7D3 was seen when excited by excitation wavelength 288 nm. TL glow curves for ZrO2:Tb3+ exhibit a glow curve with a well-defined peak centered in around 170°C. TL signal as a function of dopant concentration showed a maximum at 10 at%. The best intensity of TL response as a function of UV radiation wavelength was in 230 nm. TL response fading and reusability were also analyzed. The ZrO2:Tb3+ films has been found to have simple and sharp glow peak which should be considered for dosimetric applications.
Temperature effect on the luminescent emission of hafnium oxide doped with europium ion.
Authors: López Esquivel R I , Guzmán Mendoza J , Montalvo T Rivera , Torres J G , Guzmán Olguín J C , Falcony C.
Published: June 2019

Photoluminescent analysis of HfO2 doped with Eu3+, as a function of temperature is reported. Samples were synthesized by hydrothermal method at 200 °C of temperature and 120 minutes of reaction time, using chlorides as raw materials. The HfO2 was doped with trivalent europium ions (Eu3+) at concentrations 1, 2, 3, 5 and 10 % atomic. X-ray diffraction (XRD) showed synthesized material crystallized in monoclinic phase characteristic of HfO2. Scanning electron microscopy showed presence of particles of smaller size than 100 nm forming agglomerates. Photoluminescent analysis at room temperature for sample doped with Eu3+ (3%) display highest luminescent emission. Finally, photoluminescent analysis as a function of temperature, shown changes in luminescent intensity in 5D1 and 5D0 transitions, for 0 to 50 °C temperature range.
Effects of local distortion on the electrical properties of lead free perovskite-type electro-ceramics Ba1-xCaxTi0.9Zr0.1O3
Authors: Herrera-Pérez G , Reyes-Montero A , Canche-Tello J , Montero-Cabrera M E , Fuentes-Montero M E , Plaisier J R , Eichert D , Reyes-Rojas A , Fuentes-Cobas L E
Published: June 2019

The electro-ceramic industry has focused their attention on replacing lead-based materials due to their toxic effects and unfavourable environment impact. Barium titanate doped with calcium and zirconium denoted in this work as BCZT is a well-known perovskite-type solid solution. In particular, Ba1-xCaxTi0.9Zr0.1O3 (where x = 0, 0.1 and 0.15) compositions are located near the so called morphotropic phase boundary (MPB): coexistence of ferroelectric phases. This work shows the relationship between the crystal and electronic structure with the dielectric and piezo-ferroelectric properties. The high-resolution X-ray diffraction (HR-XRD) results suggest the coexistence of tetragonal and rhombohedral phases over the obtained compositions. The dielectric analysis indicates a relaxor behaviour with a Curie temperature in a range of 100-120°C. Piezoelectric and ferroelectric evaluation complement the electrical characterization for these compositions. Micro–X-ray absorption near edge spectroscopy (μ-XANES) was performed to monitor possible changes of electronic structure profile due to the local distortions as Ca2+ increases.
Graphene oxide with the addition of different values of Ag nanoparticles.
Authors: Pérez A Nascir , Ojeda M. M , Renteria T V M , Ojeda M Luisa , Velasquez O C
Published: June 2019

In this work, the synthesis of graphene oxide (GO) were performed also we incorporate different Ag nanoparticles concentration with the aim to improve the properties of this material due to the assembled of metallic nanoparticles. In our case we choose Ag nanoparticles since that have a good reflectivity of light and the possibility to increment the Raman intensity by effects of the surface plasmon resonance. The synthesis of the GO and the Ag nanoparticles were achieved by the Hummers method and chemical reduction, respectively. Five samples of graphene oxide were obtained, with the addition of different values of Ag nanoparticles in those samples were 0 μL, 5 μL,10 μL,15 μL y 50 μL. All samples were characterized by some spectroscopy techniques evaluating the absorption, structure and composition. We found that the Raman intensity increment for the sample of 15 μL of Ag nanoparticles, that effect could be related to the surface plasmon resonance of these nanoparticles.
Vibrational and magnetic properties of YIG ferrite powders obtained by the Pechini method
Authors: Barrón-López J F , Hernández-Cruz L E , Sánchez De-Jesús F , Bolarín-Miró A , Alvarez G , Montiel H
Published: June 2019

Yttrium iron garnet (YIG: Y3Fe5O12) ferrite powders were obtained by the Pechini method from metal nitrates, citric acid and ethylene glycol followed by thermal annealing at Tan = 900°C, 1000°C, 1100°C and 1200°C. X-ray diffraction (XRD) and Raman spectroscopy were used to study the structural and vibrational properties of YIG powders. Raman spectra of powders showed the same set of bands as the bulk YIG, but they are broadened due to spatial confinement of phonons. Magnetic properties were measured by vibrant sample magnetometer (VSM), founding that magnetic properties are strongly dependent on Tann; in particular the magnetization increases and reaches the bulk value of 27.7 emu/g at T = 1000°C.
Study of the propagation of solitary waves produced by an assembly of quantum dots through optical fibers
Authors: Horta S D , Avila D A , Torres C O
Published: June 2019

In this research, the potential use of semiconductor nanostructures as optical field sources to optimize the propagation of lossless pulses along non-linear optical fibers is studied. During this investigation, we propose the external excitation of a set of semiconductor SQD points through a source of optical pulses, giving rise to the generation of solitonic pulses that propagate through an optical fiber with non-linear optical characteristics. Theoretically, soliton formation studied from the non-linear interaction between SQD and external optical excitation. In the study, the non-linear Schrödinger NLSE equation solved numerically using the Fourier Split-Step method to understand the evolution of the soliton emitted for SQD within an optical fiber with real physical parameters.
Ultrasonic spray pyrolysis synthesis of Al, Zr, and Ti oxides multishell
Authors: Hernández L R T , Escalona A , Granados S J , Sánchez A , Orozco S
Published: June 2019

In recent years, core shell nanoparticles have received increased attention due their possible applications in catalysis, biology and materials science. Solid micro-particles with a nanostructure of concentric multilayers were obtained with spray pyrolysis technique. In this work we present the synthesis and characterization of 1 to 10 layers of micro-spheres deposited on commercial brass sheet. Each layer is formed by three films: the first one is made of aluminum oxide, the second of zirconium oxide and the last film of titanium oxide. The films were deposited by the ultrasonic spray pyrolysis technique using organometallic salts of aluminum, zirconium and titanium, employing N, N-dimethylformamide as solvent. Scanning electron microscopy micrographs of 7 and 10 layers shows details about the formation of the layers. The micro-spheres are compacted in a homogeneous and uniform film, whose hardness increases with the number of layers.
Exploring the 2-D Bateman dual system Hamiltonian: a first approach
Authors: Hernández-Saldaña H , Morales-Téllez J , García-Martínez C
Published: June 2019

Dissipation is of major interest in physics and engineering in all energy scales and, hence, it devoted a large amount of investigation. For quantum systems, an usual model for study is the Bateman dual system. Here we use the same model to explore dissipation in angular momentum instead of energy. For that matter, we start with an effective 2-D Bateman model in polar (cylindrical) coordinates and we find the expression for the Hamiltonian. Two constants of motion are found related to modified angular momenta and we test if they are in involution with the Hamiltonian, i.e., if they are integrals of motion. This is in order to verify that the corresponding quantum versions of these constants are good candidates to be a complete set of commuting observables.