bluuebunny/crossref_metadata_2025_split huggingface dataset:
Composition uniformity and large degree of strain relaxation in MBE-grown thick GeSn epitaxial layers, containing 16% Sn
Authors: Rathore Jaswant , Nanwani Alisha , Mukherjee Samik , Das Sudipta , Moutanabbir Oussama , Mahapatra Suddhasatta 
Published: February 2021

Abstract
We systematically investigate the compositional uniformity, degree of strain relaxation (DSR), defect structure and surface morphology of GeSn epitaxial layers with 16% Sn, grown by low temperature molecular beam epitaxy (MBE) on Ge-buffered Si(001) substrates. Combining atom probe tomography, reciprocal space mapping, cross-sectional transmission electron microscopy, and atomic force microscopy analyses, we demonstrate that for a layer thickness of

t

GeSn

=
250

nm

, a high DSR (∼70%) can be achieved, while maintaining compositional uniformity at the atomic scale. We find no evidence of Sn clustering in the bulk, or Sn segregation to the surface, for at least this value of

t

GeSn

. The observed compositional uniformity contrasts the well-established phenomenon of strain-relaxation enhancement of Sn content in chemical vapour deposition (CVD) growth of GeSn. The defect structure leading to strain relaxation in these MBE-grown GeSn epitaxial layers is also distinctly different from that observed in CVD growth of the alloy. We observe the co-existence of highly strain-relaxed and pseudomorphically strained regions in the grown epilayers, tentatively explained by bunching of threading dislocations. Considering that MBE growth of GeSn epitaxial layers, with such high-Sn content and layer thickness, has not been reported before, our results are encouraging for future improvements in design and fabrication of group-IV-based mid-infrared photonic devices.
Anisotropic thermal conductivity in lattice transition thermal rectifiers
Authors: Alvarez-Quintana J 
Published: February 2021

Abstract
Lattice transition materials can exist in two phases with different thermal conductivities. Because of this, phase change materials (PCMs) are considered as promising next-generation thermal rectifying materials. The performance of a thermal rectifier known as rectification factor (R) is evaluated by the ratio between the heat that preferentially flows in the forward direction and that in the reverse one. In this work, taking into consideration that PCMs have the striking characteristic of high anisotropy, we propose an analytical framework based on the thermal conductivity tensor theory for predicting the R of lattice transition thermal rectifiers. Because of lattice symmetries, model unveils that the rectification factor is ruled, as well as limited by the ratio of the principal thermal conductivity tensor components present in each phase and the thermal conductivity of the invariant phase material. Furthermore, to validate our predictions the model is applied to the existing experimental systems in the literature, providing accurately truthfulness on observed R. Hence, the analytical model is promising from both theoretical and experimental points of view to understand the effects which allow developing a procedure for engineering an enhanced performance thermal rectifying device.
Defect mediated improved charge carrier dynamics in hybrid bulk-heterojunction solar cell induced by phase pure iron pyrite nanocubes
Authors: Sharma Punit , Rana Aniket , Waheed Sobia , Pareek Saurabh , Karak Supravat 
Published: February 2021

Abstract
In this article, the synthesis of phase pure iron pyrite nanocubes (FeS2 NCs) and their various effects on the charge carrier dynamics and photovoltaic performances of P3HT:PC71BM based hybrid bulk-heterojunction solar cells have been studied. The optimum doping concentration of FeS2 NCs was found to be 0.3 wt%. For the optimally doped devices, the short-circuit current density was found to have improved from 5.47 to 7.99 mA cm−2 leading to an overall cell efficiency improvement from 2.10% to 3.22% as compared to the undoped reference devices. The enhancement in photovoltaic performance is mainly attributed to the formation of localized energy states near the band edges leading to higher carrier generation rate by 72% whereas carrier dissociation probability is also increased by 13%. Urbach energy estimation reveals that the optimally doped devices have achieved a relatively balanced amount of localized states resulting in reduced non-radiative recombination. Such localized defect states formation with FeS2 NCs doping was also found to have significant influence over the charge carrier dynamics of the active layer. Transient photocurrent and photovoltage studies revealed that FeS2 NCs assist in faster carrier extraction by reducing the transport time from 1.4 to 0.6 μs and by enhancing carrier recombination time from 51.7 to 78.9 μs for the reference and optimum devices respectively. Such an unorthodox approach of defect state assisted efficiency improvement demonstrates the importance of simultaneously understanding the charge carrier dynamics and photovoltaic performance for rational device optimization, and opens new prospects for developing high-efficiency solution processable hybrid devices.
Temporal feature prior-aided separated reconstruction method for low-dose dynamic myocardial perfusion computed tomography
Authors: Chen Zixiang , Zeng Dong , Huang Zhenxing , Ma Jianhua , Gu Zheng , Yang Yongfeng , Liu Xin , Zheng Hairong , Liang Dong , Hu Zhanli 
Published: February 2021

Abstract
Dynamic myocardial perfusion computed tomography (DMP-CT) is an effective medical imaging technique for coronary artery disease diagnosis and therapy guidance. However, the radiation dose received by the patient during repeated CT scans is a widespread concern of radiologists because of the increased risk of cancer. The sparse few-view CT scanning protocol can be a feasible approach to reduce the radiation dose of DMP-CT imaging; however, an advanced reconstruction algorithm is needed. In this paper, a temporal feature prior-aided separated reconstruction method (TFP-SR) for low-dose DMP-CT images reconstruction from sparse few-view sinograms is proposed. To implement the proposed method, the objective perfusion image is divided into the baseline fraction and the enhancement fraction introduced by the arrival of the contrast agent. The core of the proposed TFP-SR method is the utilization of the temporal evolution information that naturally exists in the DMP-CT image sequence to aid the enhancement image reconstruction from limited data. The temporal feature vector of an image pixel is defined by the intensities of this pixel in the pre-reconstructed enhancement sequence, and the connection between two related features is calculated via a zero-mean Gaussian function. A prior matrix is constructed based on the connections between the extracted temporal features and used in the iterative reconstruction of the enhancement images. To evaluate the proposed method, the conventional filtered back-projection algorithm, the total variation regularized PWLS (PWLS-TV) and the prior image constrained compressed sensing are compared in this paper based on studies on a digital extended cardiac-torso (XCAT) thoracic phantom and a preclinical porcine DMP-CT data set that take image misregistration into account. The experimental results demonstrate that the proposed TFP-SR method has superior performance in sparse DMP-CT images reconstruction in terms of image quality and the analyses of the time attenuation curve and hemodynamic parameters.
Edge turbulence in ISTTOK: a multi-code fluid validation
Authors: Dudson B D , Gracias W A , Jorge R , Nielsen A H , Olsen J M B , Ricci P , Silva C , Tamain P , Ciraolo G , Fedorczak N , Galassi D , Madsen J , Militello F , Nace N , Rasmussen J J , Riva F , Serre E 
Published: February 2021

Abstract
Fluid models used to study the edge plasma region need to be benchmarked against similar conditions given that models can strongly differ in complexity and therefore the results they produce. Via this validation study undertaken through the framework of EUROfusion Enabling Research, four state-of-the art models—GBS, Hermes/BOUT++, hot-edge-sol-electrostatic and TOKAM3X—are compared to experimental plasma turbulence measurements on the ISTTOK tokamak. Statistical comparisons of simulation and experiment data show that fluid models used here can replicate most of the experiment in terms of

I

sat

and

V

float

fluctuations despite their differences. Furthermore, it is shown that without including more complex information (like core turbulence information and domain geometry details and magnetic topological aspects) in fluid models, the results recovered vary from their experimental counterparts. Via the simulations using these codes, it is demonstrated that fluid models continue to be a good cost-effective tool in recovering many global aspects of edge plasma behaviour.
Review on performance analysis of P3HT:PCBM-based bulk heterojunction organic solar cells
Authors: Ghosekar Ishan C , Patil Ganesh C 
Published: February 2021

Abstract
Due to their low production costs, small weight, printability, solution processing, and the possibility of using flexible substrates, organic solar cells (OSCs) exhibit strong potential to be used in future solar cell technology. Major specifications for the commercialization of OSCs are the long life span of OSC devices, enhanced environmental stability and a sufficiently high power conversion efficiency (PCE). The development of low energy gap organic polymers, transport materials and multi-layer system architecture has been effective in achieving higher PCE. However, overcoming environmental stability and sustaining a longer life span are a major challenge. The instability of OSCs is the dynamic mechanism, mostly induced due to the combined impact of oxygen, incident light, and ambient, as well as processing, temperature. Studies have reported that thermal annealing of the active layer tends to a shift in the phase morphology, which typically occurs either because of the vertical phase separation or because of the process of donor–acceptor phase segregation. In this paper, various factors that affect the performance of the OSC have been comprehensively studied. Factors such as thermal stress, vertical phase segregation, material composition and tradeoff between thickness and light absorption have been discussed. This paper mainly reviews the measures carried out to improve the efficiency of conventional polymer-fullerene-based bulk-heterojunction OSCs and reports the different techniques to address these issues.
Three-dimensional constitutive model for shape-memory polymers considering temperature-rate dependent behavior
Authors: Kim Jinsu , Jeon Seung-Yeol , Hong Seokbin , An Yongsan , Park Haedong , Yu Woong-Ryeol 
Published: February 2021

Abstract
The temperature-rate dependent thermomechanical behavior of shape-memory polymers (SMPs) is challenging to study, because the microstructure of SMPs cannot rearrange instantaneously to an equilibrium configuration in response to temperature changes. Herein, we report a temperature-rate dependent three-dimensional constitutive model for SMPs based on a two-phase model consisting of rubbery and glassy phases. To describe the effect of temperature rate on SMPs, the variation of the volume fraction of each phase affected by temperature was considered under different temperature-rate conditions. Additionally, the temperature-rate dependent thermal strain was incorporated into the two-phase model. The developed constitutive model was validated by simulating the shape-memory behavior of SMPs, and by comparing the simulation and experimental results under different temperature-rate conditions.
Spatial-dependent probe transmission based high-precision two-dimensional atomic localization
Authors: Idrees Muhammad , Kalsoom Humaira , Bacha Bakth Amin , Ullah Arif , Wang Li-Gang 
Published: February 2021

Abstract
Herein, we propose a scheme for the realization of two-dimensional atomic localization in a λ-type three-level atomic medium such that the atom interacts with the two orthogonal standing-wave fields and a probe field. Because of the spatially dependent atom-field interaction, the information about the position of the atom can be obtained by monitoring the probe transmission spectra of the weak probe field for the first time. A single and double sharp localized peaks are observed in the one-wavelength domain. We have theoretically archived high-resolution and high-precision atomic localization within a region smaller than λ/25 × λ/25. The results may have potential applications in the field of nano-lithography and advance laser cooling technology.
Evaluation of effective area of air piston gauge with limitations in piston–cylinder dimension measurements
Authors: Thakur Vikas N , Sharipov Felix , Yang Yuanchao , Kumar Sandeep , Ram Jokhan , Omprakash  , Kumar Harish , Sharma Rina , Yadav Sanjay , Kumar Ashok 
Published: February 2021

Abstract
The air piston gauge (APG) has been established at the National Physical Laboratory, India (NPLI) for Pascal realization since 2002. The APG at NPLI has been considered a transfer pressure standard because it has been calibrated against the primary pressure standard, i.e. ultrasonic interferometer manometer. As per existing international protocol, the APG establishment as a primary standard, the effective area (A
e) of piston–cylinder (p–c) assembly and masses must be directly traceable to SI units. We have calculated A
e and associated uncertainty of p–c assembly using the theory of rarefaction gas dynamics, which is based on dimension measurements. The value of A
e is obtained for varying temperatures and radii of piston and cylinder in their respective uncertainty limits. The variation of the cylinder's inner radius within its uncertainty limit of 0.7 µm includes the expected effective area, i.e. 3.356 775 (5) cm2. The effective area’s expected values are obtained for the cylinder’s radius of 10.338 00 (2) mm, which is approximately 0.65 µm away from the value obtained from dimensional measurements and well within the uncertainty limit. Therefore, to get the effective area of 3.356 775 (5) cm2, the uncertainty of the cylinder’s radius should be at least one order less (similar to piston’s radius) than that of the present value. The precision in dimension measurement of the cylinder's internal radius is the critical parameter for effective area calculation of p–c assembly.
Monthly analyses of convection-related irregular flights and their linear projections for the future climate in China
Authors: Zhou Yuntao , Gong Hongjing , Fan Penglei , Li Na , Gu Lei 
Published: February 2021

Abstract
Convective weather such as thunderstorms and rain is one of the main causes of irregular flights including delays, cancelations, turnbacks and diversions. In China, summer (April–September) flights accounted for 94% of irregular flights due to convective weather in 2016–2019. The impact of summer convective weather conditions on irregular flights is however not well understood. In this research, we find that thunderstorms, as indicated by the lifted index (LI), are greatly related to these irregular flights over Southeast China. The global climate model ensemble indicates there will be robust increases in the occurrence of convective weather environments in response to further global warming. We also find that as the LI is decreasing over time, the likelihood of thunderstorm-related irregular flights is increasing. Such an increase indicates there will be a 17% increase in irregular flights by the end of the century.
Tribological behavior of polymeric 3D-printed surfaces with deterministic patterns inspired in snake skin morphology
Authors: Ballesteros Luis Miguel , Zuluaga Efraín , Cuervo Paula , Rudas J Sebastián , Toro Alejandro 
Published: February 2021

Abstract
Surface engineering can rely on biological systems to mimic characteristics of living specimens in order to develop and fabricate deterministic elements to modify friction. In this work, the tribological response of bio-inspired patterns obtained by 3D-printing for polymer-metal contact in dry conditions are discussed. The repetitive array of elements called ‘fibrils’ in the ventral scale of Phython regius snake was used as an inspiration to fabricate the deterministic surfaces. The texturized samples were 3D-printed with Nylon filament and the counterpart was AISI 304 stainless steel. The results showed that the friction coefficient was consistently lower in the tests carried out with the texturized samples in comparison to those performed with stochastic surfaces. Lower friction values were clearly correlated to geometrical descriptors of the texture patters including the Feature Slenderness Ratio (FSR) and the Feature Aspect Ratio (FAR). The analysis of polymer’s worn surfaces revealed adhesive damage, localized melting and roll formation as the main wear mechanisms.
Characterization and synthesis of Fe3O4@C nanoparticles by in-situ solid-phase method
Authors: Xiang Hengli , Ren Genkuan , Zhong Yanjun , Yang Xiushan , Xu Dehua , Zhang Zhiye , Wang Xinlong 
Published: February 2021

Abstract
Fe3O4@C nanoparticles were successfully synthesized by an in situ solid-phase method using FeSO4, FeS2, and PVP K30 as the starting materials under the nitrogen atmosphere. In addition, the mechanism of the synthetic of Fe3O4@C nanoparticles was studied through in situ characterizations. The results showed that the pyrolysis of PVP K30 participated in the solid-phase reaction and resulted in the formation of carbon shells and a reduction in particle size. The structure of the Fe3O4@C nanoparticles was core–shell with the average particle size of ∼30 nm and the thickness of the carbon shell of ∼2 nm. Besides, the Raman spectrum revealed that the carbon shell mostly existed in the form of amorphous carbon. The surface area and the pore volume of the Fe3O4@C nanoparticles were estimated to be 37.74 m2 g−1 and 0.227 cm3 g−1. Magnetization hysteresis curve exhibited the values of coercivity and remanence and saturation magnetization are found to be approximately 0.16 kOe, 12.8 emu g−1, and 77 emu g−1, respectively.
Study on the geometric structure and stability of AlnMgn (n = 2–12) clusters using density functional theory
Authors: Zhang Xiao-Pan , Shi Lei , Du Hao , Tian Yuan , Lv Fei , Yang Ming-Liang , Qu Tao 
Published: February 2021

Abstract
In this study, density functional theory was used to investigate the AlnMgn (n = 2–12) clusters on a microscopic scale. The stable structure of clusters was determined and used as the interaction energies parameter in Wilson equation to deepen the activity prediction of the Wilson equation. The properties of Mg2 and Al2 dimers calculated by using ab initio molecular dynamics were compared with experimental data to verify the reliability of the method. By characterizing the cluster structure, the average binding energy, fragmentation energy, second–order energy difference, vertical ionization potential, vertical electron affinity, chemical hardness, HOMO–LUMO gaps, and distribution of the Al–Mg clusters were determined. With an increase in the cluster size, the symmetry of the Al–Mg clusters decreased, and Al atoms gradually gathered at the center of the cluster, whereas Mg atoms were distributed on the surface of the cluster, which tended to combine with Al atoms. Clusters with even numbers were generally more stable than the adjacent odd–numbered clusters. In particular, the thermodynamic stability of the Al4Mg4 cluster was prominent and was considered as an ideal object to calculate the interaction energies in the activity prediction of Al–Mg alloys.
Generation of 6-C synthetic seismograms in stratified vertically transversely isotropic media using a generalized reflection and transmission coefficient method
Authors: Tang Le , Fang Xinding 
Published: February 2021

SUMMARYWe develop a generalized reflection and transmission coefficient method (GRTM) for generating six-component (6-C) synthetic seismograms in horizontally layered vertically transversely isotropic (VTI) media. Compared with the traditional seismic modelling approaches that only consider translational motion, our method can simultaneously produce three-component translational and three-component rotational data excited by a point vector force or a moment tensor source in a layered half-space. Horizontally layered models are widely used in near surface applications as the properties of near surface formations generally show small lateral variations and change mainly along the depth direction. The use of the VTI constitutive relation can make our method applicable to more general situations because it takes into account the characteristics of sedimentary formations. We compare our method with a finite-difference method (FDM) for a variety of velocity models and acquisition geometries. The numerical results demonstrate that accurate 6-C synthetic seismograms can be calculated using our method. The computational efficiency of our method for 6-C seismic modelling is much higher than the finite-difference method, because it can reduce a 3-D modelling problem to 2.5-D by eliminating the azimuthal dimension. Also, our method does not require to perform additional spatial interpolations to obtain the rotational components. These advantages make our method suitable to serve as a forward modelling tool for rotational seismology.
Recent advances in histone glycation: emerging role in diabetes and cancer
Authors: Mir Abdul Rouf , Habib Safia , Uddin Moin 
Published: February 2021

Abstract
Ever increasing information on genome and proteome has offered fascinating details and new opportunities to understand the molecular biology. It is now known that histone proteins surrounding the DNA play a crucial role in the chromatin structure and function. Histones undergo a plethora of posttranslational enzymatic modifications that influence nucleosome dynamics and affect DNA activity. Earlier research offered insights into the enzymatic modifications of histones; however, attention has been diverted to histone modifications induced by by-products of metabolism without enzymatic engagement in the last decade. Nonenzymatic modifications of histones are believed to be crucial for epigenetic landscape, cellular fate and for role in human diseases. Glycation of histone proteins constitutes the major nonenzymatic modifications of nuclear proteins that have implications in diabetes and cancer. It has emerged that glycation damages nuclear proteins, modifies amino acids of histones at crucial locations, generates adducts affecting histone chromatin interaction, develops neo-epitopes inducing specific immune response and impacts cell function. Presence of circulating antibodies against glycated histone proteins in diabetes and cancer has shown immunological implications with diagnostic relevance. These crucial details make histone glycation an attractive focus for investigators. This review article, therefore, makes an attempt to exclusively summarize the recent research in histone glycation, its impact on structural integrity of chromatin and elaborates on its role in diabetes and cancer. The work offers insights for future scientists who investigate the link between metabolism, biomolecular structures, glycobiology, histone–DNA interactions in relation to diseases in humans.