bluuebunny/crossref_metadata_2025 huggingface dataset:
National Outcomes of Prophylactic Lymphovenous Bypass during Axillary Lymph Node Dissection
Authors: Chiang Sarah N. , Skolnick Gary B. , Westman Amanda M. , Sacks Justin M. , Christensen Joani M.
Published: February 2022

Background Breast cancer treatment, including axillary lymph node excision, radiation, and chemotherapy, can cause upper extremity lymphedema, increasing morbidity and health care costs. Institutions increasingly perform prophylactic lymphovenous bypass (LVB) at the time of axillary lymph node dissection (ALND) to reduce the risk of lymphedema but reports of complications are lacking. We examine records from the American College of Surgeons (ACS) National Surgery Quality Improvement Program (NSQIP) database to examine the safety of these procedures.

Methods Procedures involving ALND from 2013 to 2019 were extracted from the NSQIP database. Patients who simultaneously underwent procedures with the Current Procedural Terminology (CPT) codes 38999 (other procedures of the lymphatic system), 35201 (repair of blood vessel), or 38308 (lymphangiotomy) formed the prophylactic LVB group. Patients in the LVB and non-LVB groups were compared for differences in demographics and 30-day postoperative complications including unplanned reoperation, deep vein thrombosis (DVT), wound dehiscence, and surgical site infection. Subgroup analysis was performed, controlling for extent of breast surgery and reconstruction. Multivariate logistic regression was performed to identify predictors of reoperation.

Results The ALND without LVB group contained 45,057 patients, and the ALND with LVB group contained 255 (0.6%). Overall, the LVB group was associated with increased operative time (288 vs. 147 minutes, p < 0.001) and length of stay (1.7 vs. 1.3 days, p < 0.001). In patients with concurrent mastectomy without immediate reconstruction, the LVB group had a higher rate of DVTs (3.0 vs. 0.2%, p = 0.009). Reoperation, wound infection, and dehiscence rates did not differ across subgroups. Multivariate logistic regression showed that LVB was not a predictor of reoperations.

Conclusion Prophylactic LVB at time of ALND is a generally safe and well-tolerated procedure and is not associated with increased reoperations or wound complications. Although only four patients in the LVB group had DVTs, this was a significantly higher rate than in the non-LVB group and warrants further investigation.
Multiple coherent dispersive waves generation in silicon nitride slot waveguide
Authors: Fang Yuxi , Bao Changjing , Wang Zhi , Zhang Weigang , Pan Zhongqi , Yue Yang
Published: February 2022

A method to generate multiple dispersive waves (DWs) with pumping in a normal dispersion regime is proposed. We show flexibility of producing four DWs in a silicon nitride (Si3N4) slot waveguide and explain the underlying dynamics of a four DWs generation process in detail, i.e., DWs emission via the optical wave-breaking phenomenon in an anomalous dispersion regime. Compression of the first anomalous DW results in the subsequent cascade DW generation. Combined with the soliton induced blue-shifted dispersive wave and red-shifted dispersive wave, the spectrum spans from visible to mid-IR with high coherence. The four DWs generation process has agreement with prediction of the phase-matching condition. Overall, this multiple DWs generation method in a Si3N4 waveguide provides the possibility for having an efficient, compact, and coherent mid-IR light source.
Second-harmonic generation of embedded plasmonic nanoparticle arrays via interparticle coupling
Authors: Chu Lingrui , Li Ziqi , Zhu Han , Ren Feng , Chen Feng
Published: February 2022

Efficient nonlinear frequency conversion, such as second-harmonic generation in ultracompact structures, is essential for the development of modern nanophotonic devices. Here, we demonstrate intense second-harmonic emission in scalable embedded Ag nanoparticle arrays fabricated by ion implantation into BK7 glass. The interparticle coupling effect significantly enhances the local field at the nanogap (gap size ∼ 1 nm) of two neighboring Ag nanoparticles and finally amplifies second-harmonic emission generated at the surface of plasmonic nanoparticles. Notably, the intensity of second-harmonic emission in embedded Ag nanoparticle arrays is comparable to that of two-dimensional transition metal dichalcogenides under the excitation of a fundamental wave at 1064 nm and independent of the incident polarization angles. Our work offers a promising strategy on the rapid fabrication of low-cost nonlinear optical nanostructures with great environmental stability.
Time-resolved imaging of ultrasound waveform with synchronized laser illumination
Authors: Das Subir , Hsu Yun-Yu , Kao Ying-Rue , Hsieh Bao-Yu , Kao Fu-Jen
Published: February 2022

We present a synchronous time delay technique to precisely control the illuminating laser pulses and the ultrasonic wave generation to visualize the ultrasound waveform through the Schlieren imaging method. The proposed time-resolved imaging technique offers the two-dimensional mapping of ultrasound waveform in a temporally evolved manner. The critical physical parameters, such as speed and spatial pulse length of ultrasonic waves, are visualized and calculated from image analysis. Our results suggest a protocol in characterizing ultrasound waveform, and it has the potential to reconstruct the acoustic field by accumulating the time-lapse waveforms.
Fabrication of TiO2 nanodot films using simple solution dipping method and block copolymer template
Authors: Pandey Krishna , Perez Marcos , Korveziroska Amelia , Manna Uttam , Biswas Mahua
Published: February 2022

Block copolymer (BCP) self-assembled nanostructures as a template in conjunction with a low-cost inorganic material deposition method can be a practical solution for many applications in the fields of microelectronics, optoelectronics, and plasmonics. Here, we demonstrate the fabrication of TiO2 nanodot films using polystyrene-b-polymethylmethacrylate (PS-b-PMMA) BCP as a template and a simple solution dipping process for TiO2 deposition. For this purpose, we prepared BCP templates using two different methods, namely, the selective deposition method and the masked deposition method. In the selective deposition method, as-grown self-assembled cylinder forming PS-b-PMMA was used as a template and in the masked deposition method, PMMA was etched out selectively from PS-b-PMMA nanostructured films. The scanning electron microscopy results show the average diameter of TiO2 nanodots grown by the selective deposition method is smaller compared to the masked deposition method, whereas the inter-nanodot distance is similar for both deposition methods. X-ray diffraction and photoluminescence confirm the formation of TiO2 in samples deposited by these two methods. The smaller nanodot size for the selective deposition method can be attributed to the limited interaction of the Ti precursor used here with the PMMA copolymer active functional groups. Therefore, in addition to being advantageous due to less processing steps, the selective deposition method can be used for the fabrication of lower dimensional nanostructures by identifying proper precursors and polymers and by controlling the interaction parameters. Our results will be useful for exploring interactions of other polymers with inorganic material precursors and thereby fabricating different nanostructures with desired morphologies using a simple and cost-effective dipping method.
Nanoscale imaging of dopant incorporation in n-type and p-type GaN nanowires by scanning spreading resistance microscopy
Authors: Aybeke Ece N. , Siladie Alexandra-Madalina , Vermeersch Rémy , Robin Eric , Synhaivskyi Oleksandr , Gayral Bruno , Pernot Julien , Brémond Georges , Daudin Bruno
Published: February 2022

The realization of practical semiconductor nanowire optoelectronic devices requires controlling their electrical transport properties, which are affected by their large surface/volume ratio value and potentially inhomogeneous electrical dopant distribution. In this article, the local carrier density in Si-doped and Mg-doped GaN nanowires grown catalyst-free by molecular beam epitaxy was quantitatively measured using scanning spreading resistance microscopy. A conductive shell surrounding a more resistive core was observed in Mg-doped, p-type GaN nanowires, balancing the formation of a depleted layer associated with sidewall surface states. The formation of this conductive layer is assigned to the peripheral accumulation of Mg dopants up to values in the 1020 /cm3 range, as determined by quantitative energy dispersive x ray spectroscopy measurements. By contrast, Si-doped n-type GaN nanowires exhibit a resistive shell, consistent with the formation of a depleted layer, and a conductive core exhibiting a decreasing resistivity for increasing Si doping level.
Impact force characteristics of liquid droplets and compressor blades
Authors: Tang Jie , Yang Peixin , Lu Xin , Wang Liwen
Published: February 2022

To study the influencing factors of liquid droplets on the cleaning effects of the scale layer, a three-dimensional droplet-impacting-a-blade model is constructed. The finite volume method and the volume of fluid method are used to numerically study the dynamic characteristics of a droplet impacting the fouling layer of a blade. The results show that under certain conditions, increased velocity and diameter of the droplet lead to an increase in the impact force of the droplet, and the greater the curvature of the blade surface, the smaller the vertical impact force of the droplet; likewise, the greater the impact force on cutting, the larger the corresponding spreading coefficient. The impact of liquid on the surface of the blade reduces the peak value of the droplet impact force. Finally, the increase in droplet diameter and velocity will improve the cleaning effect of the jet droplet. The larger the blade surface curvature, the wider the droplet cleaning area will be.
Asymptotic behaviour of the sphere and front of a flat sub-Riemannian structure on the Martinet distribution
Authors: Bogaevsky Ilya Aleksandrovich
Published: February 2022

The sphere and front of a flat sub-Riemannian structure on the Martinet distribution are surfaces with nonisolated singularities in three-dimensional space. The sphere is a subset of the front; it is not subanalytic at two antipodal points (the poles). The asymptotic behaviour of the sub-Riemannian sphere and Martinet front are calculated at these points: each surface is approximated by a pair of quasihomogeneous surfaces with distinct sets of weights in a neighbourhood of a pole.
Bibliography: 13 titles.
Islam, language and intra-Asian student mobility
Authors: Barnawi Osman Z.
Published: February 2022

In this study I examine the interplay of Islam, Arabic and intra-Asian student mobility. Specifically, through
semi-structured interviews with three Indonesian male students who are pursuing their Arabic medium of instruction (AMI) degrees
in Islamic Sharia at the Islamic University of Madinah in Saudi Arabia, I investigate two central questions: (1) What are the
driving forces behind Indonesian Muslim students’ mobility to Saudi Arabia for pursuing their degrees in AMI? (2) How do
Indonesian Muslim students perceive Arabic in general and AMI programs in particular? The findings reveal that the participants’
desire to move and pursue their AMI degrees in Saudi Arabia were charged with different expectations, objectives and agendas. At
the heart of these differences lies what I term as the sacralization of language phenomenon among the
participants. This very phenomenon refers to the ways in which Arabic (including its practice) is construed by the participants as
beneficial in this world and the Hereafter; as a linguistic vehicle for sustaining Islamic identity; and as a tool through which
they show their true engagement with and commitment to Islam and Islamic life. I conclude the paper with a call for serious
scholarly engagement with the sacralization of language phenomenon in the emerging scholarship of intra-Asian
student mobility within the Asian region.
Utilising an internal focus of attention during preparation and an external focus during execution may facilitate motor learning
Authors: Aiken Christopher A. , Becker Kevin A.
Published: February 2022

Research with athletes and coaches has found that attentional focus strategies are more complex than using an internal or external focus exclusively. Recently Becker et al. [2020, March 1. The effects of attentional focus in the preparation and execution of a standing long jump. Psychological Research, 84(2), 285–291] found that switching attentional focus from internal in movement preparation to external during movement execution provided a benefit over internal focus and control conditions. The purpose of this study was to investigate the effects of attentional switching on motor skill acquisition. 79 participants were randomly divided into an internal (INT), external (EXT), or switching group (IES). Individuals performed 80 acquisition trials of a golf chipping task with their prescribed attentional focus during preparation and execution. 24‐hours later 10‐trial retention and transfer tests were performed. The primary analysis revealed significant improvement during acquisition (p < .001) but no significant differences between attentional focus groups during acquisition, retention, or transfer. A secondary analysis was performed with individuals low in attentional focus adherence removed (<60%). Groups significantly improved during acquisition (p < .001). For retention IES significantly outperformed INT (p < .05). These results suggest that the detrimental effects of an internal focus are only found during skill execution and not movement preparation. It is possible for learners to benefit from both an internal and external focus so long as the cues are provided during the correct phase of skill performance.

Highlights

Attentional focus is much more complex than using either an internal or external focus of attention. This study investigated the effects of switching attention during skill acquisition from an internal to external focus.

A preliminary analysis revealed no significant differences between attentional focus groups of internal, external, or switching. One reason for this finding was the poor adherence to the prescribed focus cue.

A secondary analysis where low adherence individuals were removed revealed a significant difference between the switching group and the internal focus group during retention.

These finding suggest that the detrimental effects associated with an internal focus of attention are exclusive to using the focus during task execution. It is possible that an internal focus can still facilitate learning so long as an external focus is used during movement execution.
Polarimetric radar interferometry in the presence of differential Faraday rotation
Authors: Gilman Mikhail , Tsynkov Semyon
Published: February 2022

Faraday rotation (FR) affects the low-frequency transionospheric radar by creating cross-talk between polarizations. The baseline part of FR can be compensated for by applying an appropriate linear transformation—rotation with a known FR angle. Yet the differential Faraday rotation (dFR), which is a frequency-dependent part of FR, persists and introduces distortions into the observations. We build a simplified model with two polarimetric scattering channels that allows us to evaluate the effect of dFR on the accuracy of PolInSAR reconstruction. We also assess the severity of distortions due to dFR for the future BIOMASS mission and several other spaceborne radar systems.
A mechanism of compass-free migratory navigation
Authors: Zhao Xin , Chen Hong-Bo , Lu Li-Hua , Li You-Quan
Published: February 2022

How migratory birds can find the right way when navigating over thousands of miles is an intriguing question that has greatly interested researchers in both the fields of biology and physics for centuries. There are several putative proposals that sound intuitively plausible; all remain contested so far because these hypothetical models of magnetoreceptors that sense the geomagnetic field need either extremely high sensitivity or humankind-like intelligence to guide. Here we explore theoretically whether birds can navigate to their destination through an entirely new scenario to sense the geomagnetic field. Our proposal is based on separate peaks of the resonance-fluorescence spectrum of a four-level system derived from the ferric sulfide cluster that exists in a MagR/Cry protein complex (Drosophila CG8198) of migratory birds. As the separation of spectral peaks contains information about the geomagnetic field at both the current location and the birthland, the change of such separation cues the bird to choose the right direction to move, and double-resonance emerges once it has arrived at its destination. Our theoretical mechanism can explain previous experiments on the disorientation of migratorybirds caused by oscillating magnetic field naturally and more precisely. This work provides insight into explaining migratory navigation and motivates possible humanmade practical devices.
Light-controlled metasurface with a controllable range of reflection phase modulation
Authors: Li Ruijie , Liu Haixia , Xu Peng , Han Jiaqi , Li Long
Published: February 2022

The reconfigurable metasurface (MS) with tunable electromagnetic scattering properties has had an impact on innovative communication applications. However, the widely studied MS controlled by direct-current (DC) bias requires complex physical control circuits in array wavefront encoding, while the light-controlled MS does not. In this paper, we report a new approach for a light-controlled MS with a controllable modulation range of reflection phase, and its unit is composed of a reflection phase element based on the varactor and an optical interrogation network (OIN) based on the photoresistor so that the phase distribution of each MS unit could be independently programmed optically. To illustrate our approach, a 2-bit reflection phase MS with 10 × 10 units was fabricated and tested to achieve pencil beam scanning and orbital angular momentum beam at microwave frequencies. The simulated and measured results verify the feasibility of the proposed design. Furthermore, all the OINs on the MS are connected in parallel and powered by the same DC voltage source, which simplifies the difficulty of array expansion in MS design with a large-scale array.
Terahertz gas discharge: current progress and possible applications
Authors: Sidorov A V
Published: February 2022

Plasma created in focused beams of electromagnetic waves in the terahertz frequency range is a fairly new object in gas discharge physics. The specified range, located between the microwave and infrared regions of the spectrum of electromagnetic waves, is currently being actively developed. However, until recently, the study of discharge phenomena in it was practically inaccessible. Recent advances in its development are associated primarily with the creation of powerful sources of terahertz radiation—gyrotrons and free electron lasers. This article presents an overview of the latest results of studies of a gaseous terahertz discharge: gas breakdown, discharge propagation, features of the discharge glow, and prospects for a gaseous terahertz discharge as a point source of UV radiation.
Core@shell nanoparticles by inflight controlled coating
Authors: Ahadi Amir Mohammad , Libenská Hana , Košutová Tereza , Cieslar Miroslav , Červenková Veronika , Prokop Dejan , Dopita Milan , Biederman Hynek , Hanuš Jan
Published: February 2022

Controlled synthesis of core@shell nanoparticles (NPs) for certain applications is a difficult challenge in many nanotechnology projects. In this report, a conventional arrangement composed of a gas aggregation source (GAS) is employed to generate the core NPs, which are subsequently coated by the shell materials in a secondary planar magnetron sputtering. The important difference to the usual system is the application of the two opposing planar magnetrons in a closed field configuration. The prepared core Ag NPs by a GAS are coated/treated by the two magnetrons with Ti targets. Our findings clearly show that the shell thickness can be controlled by tuning the power delivered to the secondary magnetron plasma. Characterizations of the prepared films, by x-ray diffraction technique, disclose multi-crystalline cores covered by amorphous shells. Based on x-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy measurements, different chemistry on the NPs surfaces and volume of the NPs can be achieved by tuning the operation conditions. Furthermore, the thermal annealing process leads to the growth of the crystallite size which results in emerging some microparticles caused by accelerating Ag surface mobility. The employed technique promises a reliable route to synthesize different heterogeneous NPs with stoichiometry tunable in a wide range for multi-functional devices.
Molecular dynamic simulation on temperature evolution of SiC under directional microwave radiation
Authors: Khan Tahsin Ashraf , Burr Patrick A , Payne David , Juhl Mattias , Das Utshash , Hallam Brett , Bagnall Darren , Puthen Veettil Binesh
Published: February 2022

Silicon carbide (SiC) is widely used as the substrate for high power electronic devices as well as susceptors for microwave (MW) heating. The dynamics of microwave interaction with SiC is not fully understood, especially at the material boundaries. In this paper, we used the molecular dynamics simulation method to study the temperature evolution during the microwave absorption of SiC under various amplitudes and frequencies of the microwave electric field. Directional MW heating of a SiC crystal slab bounded by surfaces along [100] crystallographic direction shows significantly faster melting when the field is applied parallel to the surface compared to when applied perpendicular.
Contribution of nicotinamide as an intracyclic N dopant to the structure and properties of carbon dots synthesized using three α-hydroxy acids as C sources
Authors: Mao Zhen , Li Hui , Gan Na , Suo Zili , Zhang Huan , Zhao Qiang
Published: February 2022

Fixed carbon source and different dopants are mainly used to study the effect of heteroatoms on the structure and properties of carbon dots (CDs). As reactants, some dopants with conjugated structure and high nitrogen content may have important contributions to the structure and properties of doped CDs in addition to providing heteroatoms. Herein, to study the effect of fixed dopant on the structure and properties of CDs, three different CDs were synthesized using nicotinamide (NAA) and three common α-hydroxy acids (4–5 carbon atoms), and the optimal conditions were determined by orthogonal experimentation. Transmission electron microscopic micrographs showed that the average size of CDs based on nicotinamide are relatively large, up to 19.40 nm. X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy demonstrated that these CDs have graphite nitrogen and several functional group structures. Ultraviolet–visible absorption spectra, fluorescence emission spectra, and fluorescence lifetime illustrated that these CDs have similar emission centers (460–470 nm) and fluorescence processes. The influence of carbon source on the surface structure of CDs was determined by systematically analyzing the response of these CDs in different pH ranges. DFT calculations revealed the distribution characteristics of the electrons in the excited state at the HOMO and LUMO energy levels of CDs. All the above characterizations and calculations proved that NAA is a desirable dopant with an important contribution to the structure and properties of CDs.
One-pot synthesis of hexafluorobutyl acrylate hyperbranched copolymer for graphene/poly(vinylidenefluoride-trifluoroethylene- chlorofluoroethylene) dielectric composite
Authors: Jiang Huilei , Ye Huijian , Xu Lixin
Published: February 2022

Dielectric polymer film capacitor is rapidly emerging as next-generation energy storage for advanced engineering applications because of its lightweight, low cost, and processability. Further increasing energy density of polymer film with high charge–discharge efficiency is prevalent research spotlight. The filler/polymer composite with compatible interface is proved as an effective strategy to improve the energy storage capability of dielectric film. In this work, we designed hyperbranched hexafluorobutyl acrylate copolymer as miscible interface in graphene/fluoropolymer dielectric composite. A facile one-pot method was adopted to synthesize hyperbranched polyethylene grafted hexafluorobutyl acrylate (HBPE-g-HFBA) copolymer, which was adsorbed on surface of nanosheets by non-covalent interaction during exfoliation of natural graphite. The graphene/poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) composite was prepared by solution casting. The interfacial polarization is enhanced with the improved compatibility of composite that is due to the chemical similarity between hexafluorobutyl acrylate segments and fluoropolymer matrix. The energy density of 0.1 wt% nanocomposite achieves 5.0 J cm−3 with charge–discharge efficiency of 78.1% at 250 MV m−1. This work provides an optional route for non-covalent functionalization of graphene and the development of flexible polymer film capacitor with large energy storage capability.
A CT image feature space (CTIS) loss for restoration with deep learning-based methods
Authors: Zheng Ao , Liang Kaichao , Zhang Li , Xing Yuxiang
Published: February 2022

Objective. Deep learning-based methods have been widely used in medical imaging field such as detection, segmentation and image restoration. For supervised learning methods in CT image restoration, different loss functions will lead to different image qualities which may affect clinical diagnosis. In this paper, to compare commonly used loss functions and give a better alternative, we studied a widely generalizable framework for loss functions which are defined in the feature space extracted by neural networks. Approach. For the purpose of incorporating prior knowledge, a CT image feature space (CTIS) loss was proposed, which learned the feature space from high quality CT images by an autoencoder. In the absence of high-quality CT images, an alternate loss function, random-weight (RaW) loss in the feature space of images (LoFS) was proposed. For RaW-LoFS, the feature space is defined by neural networks with random weights. Main results. In experimental studies, we used post reconstruction deep learning-based methods in the 2016 AAPM low dose CT grand challenge. Compared with perceptual loss that is widely used, our loss functions performed better both quantitatively and qualitatively. In addition, three senior radiologists were invited for subjective assessments between CTIS loss and RaW-LoFS. According to their judgements, the results of CTIS loss achieved better visual quality. Furtherly, by analyzing each channel of CTIS loss, we also proposed partially constrained CTIS loss. Significance. Our loss functions achieved favorable image quality. This framework can be easily adapted to other tasks and fields.
Fine-grained calibrated double-attention convolutional network for left ventricular segmentation
Authors: Lu Chenggang , Guo Zhitao , Yuan Jinli , Xia Kewen , Yu Hengyong
Published: February 2022

Objective. Left ventricular (LV) segmentation of cardiac magnetic resonance imaging (MRI) is essential for diagnosing and treating the early stage of heart diseases. In convolutional neural networks, the target information of the LV in feature maps may be lost with convolution and max-pooling, particularly at the end of systolic. Fine segmentation of ventricular contour is still a challenge, and it may cause problems with inaccurate calculation of clinical parameters (e.g. ventricular volume). In order to improve the similarity of the neural network output and the target segmentation region, in this paper, a fine-grained calibrated double-attention convolutional network (FCDA-Net) is proposed to finely segment the endocardium and epicardium from ventricular MRI. Approach. FCDA-Net takes the U-net as the backbone network, and the encoder-decoder structure incorporates a double grouped-attention module that is constructed by a fine calibration spatial attention module (fcSAM) and a fine calibration channel attention module (fcCAM). The double grouped-attention mechanism enhances the expression of information in both spatial and channelwise feature maps to achieve fine calibration. Main Results. The proposed approach is evaluated on the public MICCAI 2009 challenge dataset, and ablation experiments are conducted to demonstrate the effect of each grouped-attention module. Compared with other advanced segmentation methods, FCDA-Net can obtain better LV segmentation performance. Significance. The LV segmentation results of MRI can be used to perform more accurate quantitative analysis of many essential clinical parameters and it can play an important role in image-guided clinical surgery.
Abnormal trend in hot carrier degradation with fin profile in short channel FinFET devices at 14 nm node
Authors: Kuo Ting-Tzu , Chen Ying-Chung , Chang Ting-Chang , Chang Kai-Chun , Yeh Chien-Hung , Ciou Fong-Min , Lin Yu-Shan , Lin Yun-Hsuan , Jin Fu-Yuan , Hung Wei-Chun , Chang Yen-Cheng , Chen Kuan-Hsu , Lin Jia-Hong
Published: February 2022

This study investigates the impact of fin profiles under hot carrier stress, which defines different base widths: wide-base samples with the smallest slope, medium-base samples, and narrow-base samples with a larger slope. The performance of the narrow samples is better than the medium samples, regardless of transconductance, on-state current, subthreshold swing or drain-induced barrier lowering, demonstrating that the narrow profile samples’ mobility and gate control are better. In long channel devices, the trend of hot carrier degradation (HCD) is in agreement with previous references, and is dependent on the transverse electric field and the fin shapes. However, this trend does not exist for short-channel devices. Positive bias stress and technology computer aided design simulation are applied for investigation and to clarify the reasons for this abnormal HCD trend. Finally, by fitting the multiple vibrational excitation (MVE) mechanism, the slope of the trend lines in the short channel devices are found to indeed match the bending mode. In other words, the disappearance of the general trend between the HCD and fin profiles is caused by the change in the mechanism in the short-channel device. Because the MVE mechanism is independent from the electric field, the narrow profile fin shape more effectively promotes gate control and better performance without affecting the reliability in short channel devices. These results can provide a clear direction for fin shape designers in the future.
Thermal, mechanical and shape fixity behaviors of shape memory cyanate under γ-ray radiation
Authors: Wang Linlin , Zhang Fenghua , Liu Yanju , Du Shanyi , Leng Jinsong
Published: February 2022

Smart materials and structures have developed rapidly, especially their application in the aerospace field has been widely valued and recognized in recent years. Shape memory cyanate ester (SMCE) resin as a class of smart polymers has a broad application prospect in space deployable structure due to the high glass transition temperature (Tg
) and excellent mechanical properties. In this work, the SMCE resins were prepared by regulating cyanate prepolymer with small molecules, showing high Tg
(> 218 °C) and high storage modulus (E' > 3.15 GPa). The SMCE resins maintained a high shape fixity rate (Rf
> 95%) at high operating temperatures (100 °C and 120 °C) for 30 d, providing a great potential application for active deformation structures. Moreover, the synergy of carboxyl (–COOH) functionalized multi-walled carbon nanotubes and short carbon fiber enhanced the thermodynamic properties and shape-changing function of the SMCE composites. The spring made by SMCE composite exhibits 360° freedom rotation, which can be used as smart structures in the aerospace field.
First principle study of band gap tuning in Cs2InSbX6 (X = Cl, Br, I) for optoelectronic and thermoelectric applications
Authors: Aslam Fatima , Ullah Hamid , Hassan M
Published: February 2022

In this work, density-functional theory based theoretical investigations of novel and less studied double perovskites Cs2InSbX6 (X = Cl, Br, I) are performed to analyze the structural and electronic behaviors. The electronic structures computed using PBEsol are further subjected to Tran-Blaha modified Becke-Johnson (TB-mBJ) potential, and tuning of the semiconducting direct band gap is observed as 1.77 eV, 1.07 eV and 0.35 eV for Cs2InSbX6 (X = Cl, Br, I), respectively. The structural stability is confirmed from the computed tolerance factors and enthalpy of formation. Thermodynamic stability is also revealed by the computed phonon spectra. The halogen ions based band gap tuning in Cs2InSbX6 (X = Cl, Br, I) show systematic variation of the computed optical parameters against impinging energies. The thermoelectric properties are found consistent with various transport parameters. The narrow band gap Cs2InSbI6 (0.35 eV) results comparatively high power factor. The band gap tuning based variations in the optical and thermoelectric parameters have revealed potential applications in energy absorption and conversion devices, respectively.
Electron paramagnetic resonance study of silicon-28 single crystal for realization of the kilogram
Authors: Mizushima Shigeki , Umeda Takahide
Published: February 2022

To realize the kilogram with high accuracy using the x-ray crystal density method, mass deficit correction to account for the number of vacancy defects in silicon-28 crystals is necessary. In this paper, we present the results of electron paramagnetic resonance (EPR) spectroscopy experiments performed on a silicon-28 crystal. The crystal was cut from near the radial center of the Si28–23Pr11 crystal boule where a relatively high vacancy defect concentration was expected within the boule, which was grown by the floating zone method. We obtained both the in-phase and out-of-phase EPR spectra, which focused on the fast- and slow-spin relaxation centers, respectively. Based on EPR measurements both in the dark and under illumination, the concentrations of phosphorus impurities with unpaired electrons were found to be between 1.6 × 1012 cm−3 and 3.4 × 1012 cm−3. In contrast, EPR-active vacancy defects in the silicon-28 crystal were not detected at the detection sensitivity of the present measurements (around 1 × 1012 cm−3), although at the Si/SiO2 interface, dangling-bond defects (P
b0 centers) were detected with an areal density between 0.4 × 1012 cm−2 and 1.7 × 1012 cm−2. The experimental detection of a larger amount of phosphorus donors under illumination indicates the presence of compensation centers (electronic levels acting as acceptors) with a concentration of at most 1.6 × 1012 cm−3. We determined that such a concentration is mainly compensated by the boron acceptors, and that there is little contribution of electrically active vacancy defects, 0.0(6) × 1012 cm−3. This value is much smaller than the previously reported concentrations of 1 × 1014 cm−3 to 4 × 1014 cm−3 for vacancy defects determined by positron annihilation spectroscopy.
New synergy effects of the lower hybrid wave and the high harmonic fast wave current drive
Authors: Yin Lan , Zheng Pingwei , Gong Xueyu , Yang Cheng , Yin Xianghui , Song Chengyi , Huang Qianhong , Chen You , Zhong Yijun
Published: February 2022

The combined drive current of the lower hybrid wave (LHW) and the high harmonic fast wave (HHFW) was studied theoretically for the first time, based on the use of low and higher β
e operational parameters in EAST. Broad and significant synergistic effects are found in the simulation, the current drive (CD) efficiency is greatly improved, and the current profile is modified as a result of the synergy between the two types of waves. The LHW interacted with the resonant electrons in low parallel velocity region and pushes them into the adjacent resonance region of the high phase velocity wave (HHFW), thus the number of fast electrons resonant with the HHFW is increased dramatically, and the driven current is enhanced. Therefore the synergy effect strongly depends on the positional relation between the velocity resonance regions of the two waves. Moreover, the effects of the parallel refractive index, the wave frequency and the wave power on the synergy effect are examined. Some problems well known in the single LHW CD or the HHFW CD may be overcome by the combined CD.
An Improved Whale Optimization Algorithm for Robot Time-jerk Optimal Trajectory Planning
Authors: Zhao Jing , Zhu Xijing , Song Tianjiao , Meng Xiaoling
Published: February 2022

Optimal path planning in the welding process enhances the processing and manufacturing efficiency. An effective algorithm for optimum path planning of a six-axis welding industrial robot is established in this paper. The robot’s trajectory is constructed using 5-th B spline interpolation in the joint space, and a cost function is constructed in terms of both time and mean jerk. An improved whale optimization algorithm (IWOA) is presented to address the time-jerk optimal trajectory planning issue. The robot’s joint positions are considered the IWOA input, while the MATLAB 2018b software is utilized to perform the optimization algorithm. Numerical simulations demonstrate that IWOA can effectively reduce the jerk of the robot while improving its work efficiency.
Research on Self-Tracking Car Based on Fuzzy-PID Control Algorithm
Authors: Zhou Yukun
Published: February 2022

Aiming at the problem that the traditional PID control algorithm can not control the motor speed of intelligent self-tracking car facing the dynamic changes of the system, this paper proposes a control algorithm based on fuzzy control rules. And the comparison between the proposed Fuzzy-PID control algorithm and the traditional PID control algorithm is analyzed by using MATLAB simulation model. The simulation results show that Fuzzy-PID control algorithm not only retains the advantages of the traditional PID control algorithm is simple and needs small calculation, but also can adapt to the dynamic changes of the system to enhance the anti-interference performance and adaptive ability of the system, and has a faster response speed compared with the traditional PID algorithm.
Nonsingular fast terminal sliding mode control for manipulator based on combinatorial reaching law
Authors: Wang Binghui , Mi Gensuo
Published: February 2022

Aiming at the problems of external disturbance, modeling errors, tracking speed and chattering in manipulator trajectory tracking control, a nonsingular fast terminal sliding mode control strategy for manipulator based on combinatorial reaching law was proposed. First, the nonlinear disturbance observer was used to observe the system’s external disturbance and modeling errors. Then, on the basis of the nonsingular fast terminal sliding mode surface, an improved nonsingular fast terminal sliding mode surface was proposed, which improves the convergence speed in the sliding motion process of sliding mode control. At the same time, a combinatorial reaching law combining the power reaching law and the variable speed reaching law was proposed, which improved the approach speed of the system under the premise of weakening the chattering. The simulation results verified the effectiveness of this control strategy.
Matching and Planning of Machining Process Based on Similarity Principles
Authors: Zhao Ping , Gao Hongbo
Published: February 2022

In order to meet the requirements of intelligent and digital process planning, a similarity-based process planning method is studied. Firstly, the characteristics of part machining features and machining process are analyzed, and the representation and retrieval model of part feature cases is established; Secondly, the principle of process combination based on factory and parallel principle is put forward, and the clustering hierarchy method is used to combine the processes, and the process elements in the process family are sorted and combined to generate the part process. The feasibility of this method is verified by an example, which can realize the digital design of machining process for complex parts such as engine cylinder block and cylinder head, thereby realize high-precision flexible machining.
Deviated Direction of Arrival Method for Radial Velocity Measurement based on Spatial Spectrum Estimation
Authors: Mei Hui , Yi Kun , Song Ke , Zhu Weicai , Wang Chao , Li Qian
Published: February 2022

In this paper, a new scheme to measure radial velocity based on direction of arrival (DOA) estimation with multiple signal classification (MUSIC) algorithm is proposed. The MUSIC algorithm usual applications in Uniforms Linear Arrays (ULA) don’t enable velocity estimation because the array signals in one snapshot are synchronous and the radial motion does not affect the steering vector. In the proposed scheme, signal snapshot is rearranged so that each vector now contains a sequence of signals from adjacent elements delayed in time, this way the steering vector input to the MUSIC algorithm includes both information of the DOA and radial velocity. An equation describing the relationship of the deviated DOA (dDOA) from the rearranged snapshot with the radial velocity and the DOA is presented. For multi-source situation, pairing problem of DOAs and dDOAs is solved by extracting the combination factors of the steering vectors and the eigenvectors in comparison between the two MUSIC implementations. Comparison with the traditional FFT method shows that a higher accuracy of velocity can be achieved by the proposed method.
Performance Enhancement of Finned Tube Heat Exchanger using New Vortex Generator
Authors: Rai Shubhanshu , Singh Shobhana
Published: February 2022

The present work aims to investigate a performance enhancement in an H-shaped finned tube heat exchanger using a new design of winglet vortex generator. The new design has an aerodynamic shape that reduces the pressure drop and enhances the heat transfer, resulting into an improvement in the overall thermo-hydraulic performance. A three-dimensional model is developed using ANSYS fluent to carry out simulations for Reynolds number varying between 5000 ≤ Re ≤ 11000 and to predict the net enhancement in the heat exchanger performance. The validation of the model is done using experimentally developed correlations of dimensionless pressure drop and heat transfer characteristics. Comparative results for the finned tube heat exchanger with and without vortex generator are presented. Results indicate a significant enhancement in the heat transfer characteristics of the finned tube heat exchanger with the new design of vortex generator. Volume goodness ratio and Colburn j-factor found to be 19.63% and 30.33% higher than the baseline finned tube heat exchanger without any vortex generator.
Estimation of Shearing and Peeling Thermal Stress of Spinel Coated Metallic Interconnects of Solid Oxide Fuel Cells
Authors: Pavan Sai Dosawada , Singh Sikarwar Basant , Kumar Singh Rajeev
Published: February 2022

Interconnects are used in solid oxide fuel cells (SOFCs) for connecting the fuel cell stacks. These interconnect are coated with spinel oxides to prevent the formation of a native scale oxide layer under high heat flux conditions. Generally, the SOFCs are subjected to thermal shock during their operation. At the interfaces of these coating, shear stresses and peeling stresses were induced due to a mismatch between the thermal expansion coefficient of coating and native scale thickness. These stresses peel off the coating layers which affect the interconnect performance. In this paper, the effect of varying native scale thickness at two different coating thicknesses on the shearing stress and peeling stress of the interconnects is analytically calculated along the two different interconnect thicknesses. The oxidation kinetics of spinel-coated SOFCs interconnects with the analytical equations relating native scale thickness with the time of SOFCs operation were reported. As per our analysis, we concluded that these stresses majorly depend on the thickness and the mechanical properties of the interconnects, native scale and a coating layer.
Computational study for the optimization of Ranque-Hilsch vortex tube with the variation of number of inlet chamber and distance between the chambers
Authors: Kant Singh Ravi , Kumar Pramanick Achintya , Chandra Rana Subhas
Published: February 2022

The purpose of the present study is to analyse the improvement in the performance of vortex tubes numerically. The air is taken as the working fluid in the compressible, axisymmetric 3-D, turbulent flow, and steady-state vortex tube. The standard k-ɛ turbulent model has been used for flow simulation in ANSYS FLUENT software with different pressure at the inlet and validated with experimental outcomes. It is found that there is an increment of 9.09 % in the cold temperature gradient with three inlet chambers as compared to single chamber. When inlet chamber numbers change from three to four, a decrease in the cold temperature gradient is recorded. When the distance between the inlet chamber increases from 8 mm to 32 mm, there is a decrease in the vortex tube’s cold temperature gradient. Therefore, it indicates that the optimum number of inlet chambers to obtain maximum cold temperature gradient, i.e., minimum cold exit temperature for the given specification of the vortex tube essential to have three inlet chambers, and the optimum distance between the inlet chambers 8 mm, is recommended.
Application of Hybrid Method Based On MRT-Lattice Boltzmann and Finite Difference to Study Heat Transfer in Three Dimensions
Authors: Benhamou J. , Lahmer E. B. , Jami M. , Moussaoui M. A. , Mezrhab A. , Phanden R. K.
Published: February 2022

The importance of studying the cooling of electronic components, which can be represented by obstacles, by natural or forced convection, has led our research laboratory to study this type of problem in 2D for many years. In this present article, the code is developed to be able to simulate heat transfers in 3D using a hybrid method. This approach is built on two numerical approaches viz the “Lattice Boltzmann method” (LBM) for the study of the fluid flow and the “Finite Difference Method” (FDM) for the calculation of the temperature field. The present numerical code is validated in the case of natural convection in a cubic cavity packed with air. Subsequently, the heat exchange between two cold vertical walls and a heated obstacle placed at center of cavity is studied.
Effect of anti-oxidant additive on oxidation stability of biodiesel
Authors: Yadav Khushbu , Bisht Anshul , Anwar Sohrab , Kharbanda Civarin
Published: February 2022

Due to growth in population and lifestyle, energy consumption is also rapidly increasing with our everyday life. The demand for petroleum products is constantly increasing ever since it has been discovered and being a non-renewable resource, we have it in limited quantities. We are in need to discover an alternate fuel that can be used to replace petroleum products. Considering this, the use of biodiesel can be one of the possible solutions for the future energy demand if the properties of biodiesel can be matched with that of petroleum products, as biodiesel is a renewable and bio-degradable fuel. The biodiesel has been prepared by using Sesame oil and its oxidation stability has been tested with the help of the rancimat test. It has been attempted to increase the oxidation stability of the biodiesel by the addition of antioxidant additives and the most common additives like TBHQ and PY have been used. The research compares the effect of Diphenylamine (DPA) as an antioxidant additive with the results of other additives. And it has been observed that all three of the additives have an almost similar effect on oxidation stability.