bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural and optical properties of self-assembled AlN nanowires grown on SiO2/Si substrates by molecular beam epitaxy
Authors: Gačević Ž , Grandal J , Guo Q , Kirste R , Varela M , Sitar Z , Sánchez García M A 
Published: February 2021

Abstract
Self-assembled AlN nanowires (NWs) are grown by plasma-assisted molecular beam epitaxy (PAMBE) on SiO2/Si (111) substrates. Using a combination of in situ reflective high energy electron diffraction and ex situ x-ray diffraction (XRD), we show that the NWs grow nearly strain-free, preferentially perpendicular to the amorphous SiO2 interlayer and without epitaxial relationship to Si(111) substrate, as expected. Scanning electron microscopy investigation reveals significant NWs coalescence, which results in their progressively increasing diameter and formation of columnar structures with non-hexagonal cross-section. Making use of scanning transmission electron microscopy (STEM), the NWs initial diameters are found in the 20–30 nm range. In addition, the formation of a thin (≈30 nm) polycrystalline AlN layer is observed on the substrate surface. Regarding the structural quality of the AlN NWs, STEM measurements reveal the formation of extended columnar regions, which grow with a virtually perfect metal-polarity wurtzite arrangement and with extended defects only sporadically observed. Combination of STEM and electron energy loss spectroscopy reveals the formation of continuous aluminum oxide (1–2 nm) on the NW surface. Low temperature photoluminescence measurements reveal a single near-band-edge (NBE) emission peak, positioned at 6.03 eV (at 2 K), a value consistent with nearly zero NW strain evidenced by XRD and in agreement with the values obtained on AlN bulk layers synthesized by other growth techniques. The significant full-width-at-half-maximum of NBE emission, found at ≈20 meV (at 2 K), suggests that free and bound excitons are mixed together within this single emission band. Finally, the optical properties of the hereby reported AlN NWs grown by PAMBE are comprehensively compared to optical properties of bulk, epitaxial and/or columnar AlN grown by various techniques such as: physical vapor transport, metal organic vapor phase epitaxy, metal organic chemical vapor deposition and molecular beam epitaxy.
Physicochemical defect guided dewetting of ultrathin films to fabricate nanoscale patterns
Authors: Das Abhijna , Bolleddu Ravi , Singh Amit Kumar , Bandyopadhyay Dipankar 
Published: February 2021

Abstract
Pathways to fabricate self-organized nanostructures have been identified exploiting the instabilities of ultrathin (<100 nm) polystyrene (PS) film on the polydimethylsiloxane (PDMS) substrates loaded with discrete and closely packed gold nanoparticles (AuNPs). The AuNPs were deposited on the PDMS substrates by chemical treatment, and the size and periodicity of the AuNPs were varied before coating the PS films. The study unveils that the physicochemical heterogeneity created by the AuNPs on the PDMS surface could guide the hole-formation, influence the average spacing between the holes formed at the initial dewetting stage, and affects the spacing and periodicity of the droplets formed at the end of the dewetting phase. The size and spacing of the holes and the droplets could be tuned by varying the nanoparticle loading on the PDMS substrate. Interestingly, as compared to the dewetting of PS films on the homogeneous PDMS surfaces, the AuNP guided dewetted patterns show ten-fold miniaturization, leading to the formation of the micro-holes and nanodroplets. The spacing between the droplets could also see a ten-fold reduction resulting in high-density random patterns on the PDMS substrate. Further, the use of a physicochemical substrate with varying density of physicochemical heterogeneities could impose a long-range order to the dewetted patterns to develop a gradient surface. The reported results can be of significance in the fabrication of high-density nanostructures exploiting the self-organized instabilities of thin polymers films.
SnO
x
/graphene anode material with multiple oxidation states for high-performance Li-ion batteries
Authors: Zhang Wenlan , Zheng Maojun , Li Fanggang , You Yuxiu , Jiang Dongkai , Yuan Hao , Ma Li , Shen Wenzhong 
Published: February 2021

Abstract
Tin and its oxides are promising anode materials owing to their high theoretical capacity, rich resource, and environmental benignity. To achieve low cost and green synthesis, a facile synthetic route of SnO
x
/graphene composites is proposed, using a simple galvanic replacement method to quickly obtain abundant foamed tin as raw material and ball milling method to realize a mechanochemical reaction between SnO
x
(0 ≤ x ≤ 2) and graphene. Under different annealing conditions, the foamed tin is converted to tin oxides with multiple oxidation states (Sn3O4, SnO, and SnO2). These unique components can greatly affect the electrochemical performance of the electrode in LIBs. The as-prepared electrode (SnO
x
-300/G) obtained by annealing foamed tin at 300 °C for 4 h and combining SnO
x
powders with graphene via ball milling shows great cycling stability, retaining a high capacity of 786 mA h g−1 at 0.1 A g−1 after 150 cycles, and its initial Coulombic efficiency can reach 84.03%. Thus, this facile synthesis can provide an environmentally friendly route for commercial production of high-performance energy storage materials.
Balanced strength-toughness, thermal conductivity and self-cleaning properties of PMMA composites enabled by terpolymer grafted carbon nanotube
Authors: Song Shiqiang , Li Qinglan , Zhang Cuifen , Liu Zijin , Fan Xin , Zhang Yong 
Published: February 2021

Abstract
Achieving a balanced strength-toughness in polymer composites is a challenge largely because of poor interfacial interaction between the fillers and matrix. Here, we report that terpolymer grafted multi-wall carbon nanotubes (Ter-CNT) imparted good dispersion of CNT in matrix and strong CNT-matrix interaction. With the addition of 2 vol% filler into polymethyl methacrylate (PMMA) matrix, the composite exhibited simultaneously a balanced strength-toughness property with flexural strength of 72.3 MPa, toughness of 10.1 MJ m−3, which increased by 40.1% and 578% compared with those of pure PMMA. In addition, the composite also shows a high static contact angle (110.3°), and thermal conductivity (0.50 Wm K−1), which endow the composite with good self-cleaning and thermal management capabilities. Thus, this preparation process shows guidance for the design of polymer composite with integrated high strength-toughness, thermal conductivity and good self-cleaning.
Ultrafast scattering dynamics of coherent phonons in Bi1−x
Sb
x
in the Weyl semimetal phase
Authors: Komori Yuta , Saito Yuta , Fons Paul , Hase Muneaki 
Published: February 2021

Abstract
We investigate ultrafast phonon dynamics in the Bi1−x
Sb
x
alloy system for various compositions x using a reflective femtosecond pump-probe technique. The coherent optical phonons corresponding to the A1g
local vibrational modes of Bi–Bi, Bi–Sb, and Sb–Sb are generated and observed in the time domain with a few picoseconds dephasing time. The frequencies of the coherent optical phonons were found to change as the Sb composition x was varied, and more importantly, the relaxation time of those phonon modes was dramatically reduced for x values in the range 0.5–0.8. We argue that the phonon relaxation dynamics are not simply governed by alloy scattering, but are significantly modified by anharmonic phonon–phonon scattering with implied minor contributions from electron–phonon scattering in a Weyl-semimetal phase.
Significance of Reynolds number, lower and upper rotating disks on the dynamics of water conveying graphene and silver nanoparticles between rotating disks
Authors: Mahesh A , Varma S V K , Raju C S K , Jayachandra Babu M , Animasaun I L , Shah Nehad Ali 
Published: February 2021

Abstract
Despite numerous reports on the newly discovered hybrid nanofluid, little is known on the influence of increasing Reynolds number, stretching of lower, and upper disks on the dynamics of water conveying graphene and silver between rotating disks when Lorentz force, Joule heating, suction, thermal radiation of thermal energy, and Cattaneo-Christov heat flux are highly significant. This report provides insight into such transport phenomenon with an emphasis on the increasing effects of Reynolds number, stretching of lower, and upper disks. Initially, leading equations of motion and energy are transmuted into a system of nonlinear ordinary differential equations with the aid of suitable (Von-Karman) similarity transmutations. Later, by enforcing shooting procedure (R-K 4th order based) to obtain the numerical solutions. Based on the analysis, it is worth concluding that increasing the Reynolds number improves the thermal field but reduces the tangential velocity. Entropy generation is an increasing property of stretching lower and upper disks but these are yardsticks for decreasing Bejan number.
J—state solutions and thermodynamic properties of the Tietz oscillator
Authors: Eyube E S , Yerima J B , Ahmed A D 
Published: February 2021

Abstract
In this work, we have solved the radial part of the Schrödinger equation with Tietz potential to obtain explicit expressions for bound state ro-vibrational energies and radial eigenfunctions. The proper quantization rule and ansatz solution technique were used to arrive at the solutions. In modeling the pseudo-spin–orbit term of the effective potential, the Pekeris-like and the Greene-Aldrich approximation recipes were applied. Using our equation for eigen energies, we have deduced expression for bound state energy eigenvalues of Deng-Fan oscillator. The result obtained agrees with available literature data for this potential. Also, for arbitrary values of rotational and vibrational quantum numbers, we have calculated bound state energies for the Tietz oscillator. Our computed results are in excellent agreement with those in the literature. Furthermore, the result showed that unlike Greene-Aldrich approximation, energies computed based on Pekeris-like approximation are better and almost indistinguishable from numerically obtained energies of the Tietz oscillator in the literature. With the help of our formula for ro-vibrational energy, analytical expressions for some important thermodynamic relations were also derived for the Tietz oscillator. The derived thermal functions which include ro-vibrational: partition function, free energy, mean energy, entropy and specific heat capacity were subsequently applied to the spectroscopic data of KI diatomic molecule. Studies of the thermal functions indicated that the partition function decreases monotonically as the temperature is raised and increases linearly for increase in the upper bound vibrational quantum number. On the other hand, increase in either temperature or upper bound vibrational quantum number amounts to monotonic rise in the entropy of the KI molecules
Reduction of PDF uncertainty in the measurement of the weak mixing angle at the ATLAS experiment *
Authors: Fu Yao , Yang Siqi , Liu Minghui , Han Liang , Hou Tie-Jiun , Schmidt Carl , Wang Chen , Yuan C.-P. 
Published: February 2021

Abstract
We investigate the parton distribution function (PDF) uncertainty in the measurement of the effective weak mixing angle

at the CERN Large Hadron Collider (LHC). The PDF-induced uncertainty is large in proton-proton collisions at the LHC due to the dilution effect. The measurement of the Drell-Yan forward-backward asymmetry (

) at the LHC can be used to reduce the PDF uncertainty in the

measurement. However, when including the full mass range of lepton pairs in the

data analysis, the correlation between the PDF updating procedure and the

extraction leads to a sizable bias in the obtained

value. From our studies, we find that the bias can be significantly reduced by removing Drell-Yan events with invariant mass around the Z-pole region, while most of the sensitivity in reducing the PDF uncertainty remains. Furthermore, the lepton charge asymmetry in the W boson events as a function of the rapidity of the charged leptons,

, is known to be another observable which can be used to reduce the PDF uncertainty in the

measurement. The constraint from

is complementary to that from

, and thus no bias affects the

extraction. The studies are performed using the error PDF Updating Method Package (ePump), which is based on Hessian updating methods. In this article, the CT14HERA2 PDF set is used as an example.
Wrist-driven passive grasping: interaction-based trajectory adaption with a compliant anthropomorphic hand
Authors: Gilday Kieran , Hughes Josie , Iida Fumiya 
Published: February 2021

Abstract
The structure of the human musculo-skeletal systems shows complex passive dynamic properties, critical for adaptive grasping and motions. Through wrist and arm actuation, these passive dynamic properties can be exploited to achieve nuanced and diverse environment interactions. We have developed a passive anthropomorphic robot hand that shows complex passive dynamics. We require arm/wrist control with the ability to exploit these. Due to the soft hand structures and high degrees of freedom during passive-object interactions, bespoke generation of wrist trajectories is challenging. We propose a new approach, which takes existing wrist trajectories and adapts them to changes in the environment, through analysis and classification of the interactions. By analysing the interactions between the passive hand and object, the required wrist motions to achieve them can be mapped back to control of the hand. This allows the creation of trajectories which are parameterized by object size or task. This approach shows up to 86% improvement in grasping success rate with a passive hand for object size changes up to ±50%.
A health impact assessment of long-term exposure to particulate air pollution in Thailand
Authors: Mueller William , Vardoulakis Sotiris , Steinle Susanne , Loh Miranda , Johnston Helinor J , Precha Nopadol , Kliengchuay Wissanupong , Sahanavin Narut , Nakhapakorn Kanchana , Sillaparassamee Ratthapol , Tantrakarnapa Kraichat , Cherrie John W 
Published: February 2021

Abstract
Particulate air pollution causes a spectrum of adverse health effects affecting the respiratory, cardiovascular, neurological, and metabolic systems that are hypothesised to be driven by inflammation and oxidative stress. Millions of premature deaths each year are attributed to exposure to ambient particulate matter (PM). We quantified health and economic impacts from long-term exposure to ambient PM2.5 in the population of Thailand for 2016. We collected data on ambient PM2.5 concentrations from automatic monitoring stations across Thailand over 1996–2016. We used historic exposure to PM2.5 to estimate the mortality in each province from lower respiratory infections (LRIs), stroke, chronic obstructive pulmonary disease, lung cancer, and ischaemic heart disease, and also assessed diabetes mortality, as well as incident cases of dementia and Parkinson’s disease, in supplementary analyses. We applied risk estimates from the Global Exposure Mortality Model to calculate attributable mortality and quantify disability-adjusted life years (DALYs); we based economic costs on the value of a statistical life (VSL). We calculated 50 019 (95% confidence interval [CI]: 42 189–57 849) deaths and 508 918 (95% CI: 438 345–579 492) DALYs in 2016 attributed to long-term PM2.5 exposure in Thailand. Population attributable fractions ranged from 20% (95% CI: 10% to 29%) for stroke to 48% (95% CI: 27% to 63%) for LRIs. Based on the VSL, we calculated a cost of US$ 60.9 billion (95% CI: US$ 51.3–70.4 billion), which represents nearly 15% of Thailand’s gross domestic product in 2016. While progress has been made to reduce exposure to ambient PM2.5 in Thailand, continued reductions based on stricter regulatory limits for PM2.5 and other air pollutants would help prolong life, and delay, or prevent, onset of cardiorespiratory and other diseases.
Correlation Analysis of Indoor and Outdoor PM2.5 and Exploration of Prevention Methods
Authors: Pan Hui , Wang Hongyun , Qian Yong , Tang Yan 
Published: February 2021

Abstract
In order to study the correlation of indoor and outdoor PM2.5 concentrations, five sampling points are selected in Hunnan New District of Shenyang City. The PM2.5 concentration inside and outside the five buildings were monitored in December 2018. After that, the writers analyze the variation characteristics and trends, and explore the prevention and control methods to indoor and outdoor PM2.5. The results show that there is a significant correlation between indoor and outdoor PM2.5 concentration, and the concentration is affected by opening or closing windows. When there is no indoor pollution source, indoor pollutants mainly come from outdoor infiltration. The prevention and control of PM2.5 pollution can be divided into indoor and outdoor aspects. Scholars often ignore the harm of PM2.5 to human body when they stay in the house. In indoor environment, PM2.5 is analyzed through aerodynamics. Due to the slow air flow, the inhalation volume of human body is more than that in the outdoor environment with fast air flow. In this paper, we will discuss how to reduce the harm of PM2.5 to human body and create a healthy living environment for residents.
Research on adaptive ship trim energy saving scheme based on intelligent loading
Authors: Gao Yibo 
Published: February 2021

Abstract
The system is a set of control system based on ship trimming energy-saving designed through deep learning algorithm, particle swarm algorithm and data optimization. Through the deep learning algorithm, the collected data is deep learning, the result of intelligent learning is used as the objective function, and the particle swarm algorithm combined with the loading software is used to adjust the loading state, sail with a fixed inclination angle and collect this fixed inclination angle during the voyage. A certain range of nearby data is systematically revised to make the system more perfect. Finally, a universal method can be obtained, which can be applied to different types of ships, and the corresponding trim optimization suggestions will be given to the complicated factors encountered in the navigation process.
Bioremediation of heavy metals pollution from acidic coal gangue with sulfate-reducing bacteria
Authors: Ma Daozhi , Liu Xinyu , Zhang Mingjiang , Wang Jianlei , Hu Xuewu , Yan Xiao , Tang Chuiyun , Zhong Juan 
Published: February 2021

Abstract
Acid mine drainage (AMD) generated by acidic coal gangue has caused coal mine area environmental degradation. Sulfate-reducing bacteria (SRB) was used to inhibit the oxidation of metal sulfide minerals from acidic coal gangue in Kaili city, Guizhou province. Four experimental groups (named as CK, R-M, R-S, R-SCa) were carried out, the results showed that SRB can effectively raise the pH (2.3 in CK, 7.8 in R-SCa) and inhibit heavy metals leachability. The low initial pH of the system can retard the start-up of sulfate reduction process. The leaching toxicity test indicated that the leachate of heavy metals in coal gangue after bioremediation was significantly reduced. High-throughput sequencing analysis showed the diversity of SRB genera in R-SCa (e.g., Desulfotomaculum and Desulfobulbus was detected) was enhanced in comparation to R-M and R-S. The results demonstrated that SRB significantly inhibit acidic coal gangue contamination and the biostimulation is also a potential solution due to indigenous SRB existence.
Study on the complaining behavior of tourists in Scenic spots: The Case in Shaanxi China
Authors: Duan Zhaowen , Zhang Tingwei , Jiang Rui , Xie Shan , Sun Hanyu 
Published: February 2021

Abstract
With the development of the Internet and the popularization of online social platforms, online reviews have become an important channel for tourists to express their travel experience, and they have also become important information references for tourism companies to improve their products and services. This study took 9 tourist attractions in Shaanxi Province as the research object, collected tourist negative word of mouth on TripAdvisor and Ctrip, and explored the online complaining behavior of tourists in the scenic spots. The results show that: (1) Failed scenic services, mismatches between expectations and the scenic environment, not being treated fairly by scenic employees, and other reasons are the main motives that cause tourists to complain online. (2) Tourists’ complaints about scenic spots are mainly concentrated in five areas: Crowded, tourism attraction, service, tickets, management and others. The complaints of tourists from different scenic spots are slightly different. (3) Tourists of different nationalities have different incomes and cultural backgrounds, which lead to different complaints about the scenic spots. The research results of this article are conducive to the managers of scenic spots to understand the content of tourists’ complaints and the reasons of tourists’ complaining behaviors, and it is conducive to the smooth implementation of the remedial measures after the event by enterprises, thereby enhancing the satisfaction of tourists.
Biodiesel synthesis by transesterification using coal-based solid acid catalyst
Authors: Yu Hewei , Niu Shengli , Lu Chunmei , Wei Wei , Zhang Xingyu 
Published: February 2021

Abstract
The medium metamorphic degree of bituminous coal with high oxygen content and low ash content is selected as the carbon carrier to prepare an efficient carbon-based solid acid catalyst through partial carbonization and sulfonation approach, and then is employed to catalyze transesterification of palm oil with methanol for biodiesel production. The strength of catalyst is characterized by Hammett inductor method. The reaction parameters are optimized by single factor method. Results demonstrate that the prepared catalyst possesses the Hammett acid strength range of 0.8<H0<3.3. The maximum biodiesel yield of 97.8% is obtained at catalyst dosage of 6 wt.%, transesterification temperature of 160 °C, molar ratio of methanol to palm oil of 18 and stirring rate of 1000 rpm for 8 h. Moreover, the catalyst exhibits satisfactory activity in catalyzing simultaneous esterification and transesterification when 20 wt.% oleic acid is added to palm oil.
Building Digital Operation and Maintenance Based on BIM
Authors: Yu Wenhong , Bai Jinchao , Li Hui 
Published: February 2021

Abstract
This paper analyzes the difference between digital operation and traditional operation, expounds the obvious advantages of digital operation and maintenance by comparing in many aspects, and expounds the importance of BIM technology in digital operation and maintenance management. However, the digitalization of operation and maintenance management has just started, so this paper analyze the operation process of digital building operation and maintenance system, and put forward the prospect of digital operation and maintenance management in the future.