bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular phyloecology suggests a trophic shift concurrent with the evolution of the first birds
Authors: Wu Yonghua
Published: May 2021

Birds are characterized by evolutionary specializations of both locomotion (e.g., flapping flight) and digestive system (toothless, crop, and gizzard), while the potential selection pressures responsible for these evolutionary specializations remain unclear. Here we used a recently developed molecular phyloecological method to reconstruct the diets of the ancestral archosaur and of the common ancestor of living birds (CALB). Our results suggest a trophic shift from carnivory to herbivory (fruit, seed, and/or nut eater) at the archosaur-to-bird transition. The evolutionary shift of the CALB to herbivory may have essentially made them become a low-level consumer and, consequently, subject to relatively high predation risk from potential predators such as gliding non-avian maniraptorans, from which birds descended. Under the relatively high predation pressure, ancestral birds with gliding capability may have then evolved not only flapping flight as a possible anti-predator strategy against gliding predatory non-avian maniraptorans but also the specialized digestive system as an evolutionary tradeoff of maximizing foraging efficiency and minimizing predation risk. Our results suggest that the powered flight and specialized digestive system of birds may have evolved as a result of their tropic shift-associated predation pressure.
Instability of U3Si2 in pressurized water media at elevated temperatures
Authors: Migdisov Artaches , Nisbet Haylea , Li Nan , White Joshua , Xu Hongwu , Nelson Andrew , Roback Robert
Published: May 2021

Following the Fukushima Daiichi accident, significant efforts from industry and the scientific community have been directed towards the development of alternative nuclear reactor fuels with enhanced accident tolerance. Among the proposed materials for such fuels is a uranium silicide compound (U3Si2), which has been selected for its enhanced thermal conductivity and high density of uranium compared to the reference commercial light water reactor (LWR) nuclear fuel, uranium oxide (UO2). To be a viable candidate LWR fuel, however, U3Si2 must also demonstrate that, in the event of this fuel coming in contact with aqueous media, it will not degrade rapidly. In this contribution, we report the results of experiments investigating the stability of U3Si2 in pressurized water at elevated temperatures and identify the mechanisms that control the interaction of U3Si2 under these conditions. Our data indicate that the stability of this material is primarily controlled by the formation of a layer of USiO4 (the mineral, coffinite) at the surface of U3Si2. The results also show that these layers are destabilized at T > 300 °C, leading to the complete decomposition of U3Si2 and its pulverization due to its full oxidation to UO2.
A no-go theorem for the persistent reality of Wigner’s friend’s perception
Authors: Allard Guérin Philippe , Baumann Veronika , Del Santo Flavio , Brukner Časlav
Published: May 2021

The notorious Wigner’s friend thought experiment (and modifications thereof) has received renewed interest especially due to new arguments that force us to question some of the fundamental assumptions of quantum theory. In this paper, we formulate a no-go theorem for the persistent reality of Wigner’s friend’s perception, which allows us to conclude that the perceptions that the friend has of her own measurement outcomes at different times cannot “share the same reality”, if seemingly natural quantum mechanical assumptions are met. More formally, this means that, in a Wigner’s friend scenario, there is no joint probability distribution for the friend’s perceived measurement outcomes at two different times, that depends linearly on the initial state of the measured system and whose marginals reproduce the predictions of unitary quantum theory. This theorem entails that one must either (1) propose a nonlinear modification of the Born rule for two-time predictions, (2) sometimes prohibit the use of present information to predict the future—thereby reducing the predictive power of quantum theory—or (3) deny that unitary quantum mechanics makes valid single-time predictions for all observers. We briefly discuss which of the theorem’s assumptions are more likely to be dropped within various popular interpretations of quantum mechanics.
Towards ferroelectricity-inducing chains of halogenoantimonates(iii) and halogenobismuthates(iii)
Authors: Owczarek Magdalena , Szklarz Przemysław , Jakubas Ryszard
Published: May 2021

A discovered abundance of structures with rare and highly-desired anionic chains is examined to identify structural factors leading to the chains' formation.
Development of a high-throughput device for liquid-phase microextraction coupled with gas chromatography-mass spectrometry for the determination of benzene derivatives in environmental water
Authors: Li Zhiqiang , Guo Zhian , Chen Xiaomei , Liu Jie , Xu Yidong , Wang Yi , Zhao Jingchan
Published: May 2021

A liquid phase microextraction device that does not require centrifugation and transfer of solvent.
A highly sensitive electrochemical biosensor for microRNA122 detection based on a target-induced DNA nanostructure
Authors: Shen Ding , Hu Wei , He Qiyi , Yang Huiyi , Cui Xiping , Zhao Suqing
Published: May 2021

A highly sensitive electrochemical biosensor employing tetrahedral DNA nanostructure and signal amplification strategies have been constructed, and this method could be used as a universal platform for trace microRNA detection.
Adriamycin coated silica microspheres as labels for cancer biomarker alpha-fetoprotein detection
Authors: Meng Wenwen , Li Mengyao , Zhang Yuzhong
Published: May 2021

Adriamycin (ADM)-coated silica microspheres as a label for the sensitive detection of a cancer biomarker alpha-fetoprotein (AFP) was reported.
3D bio-printed biphasic scaffolds with dual modification of silk fibroin for the integrated repair of osteochondral defects
Authors: Deng Changxu , Yang Jin , He Hongtao , Ma Zhenjiang , Wang Wenhao , Zhang Yuxin , Li Tao , He Chuanglong , Wang Jinwu
Published: May 2021

Repair of osteochondral defects is still a challenge, especially the regeneration of hyaline cartilage.
On the support dependency of the CO2 methanation – decoupling size and support effects
Authors: Ilsemann Jan , Murshed Mangir M. , Gesing Thorsten M. , Kopyscinski Jan , Bäumer Marcus
Published: May 2021

The influence of the support basicity, according to the Lewis and Brønsted definition, was investigated for the CO2 methanation over isostructural Ru catalysts.
Peanut sprout rich in p-coumaric acid ameliorates obesity and lipopolysaccharide-induced inflammation and the inhibition of browning in adipocytes via mitochondrial activation
Authors: Seo Seok Hee , Jo Sang-Mi , Truong Tien Thi My , Zhang Guiguo , Kim Dong-Shin , Lee Myoungsook , Lee Yunkyoung , Kang Inhae
Published: May 2021

High fat diet-induced obesity and lipopolysaccharide-induced inflammation/inhibition of the browning of adipocytes were reversed by p-coumaric acid-enriched peanut sprouts.
Adsorbed xenon propellant storage: are nanoporous materials worth the weight?
Authors: Huynh Melanie T. , Gantzler Nickolas , Hough Samuel , Roundy David , Thallapally Praveen K. , Simon Cory M.
Published: May 2021

Nanoporous materials could be used to store xenon propellant onboard spacecraft.
AFM force-clamp spectroscopy captures the nanomechanics of the Tad pilus retraction
Authors: Mignolet Johann , Mathelié-Guinlet Marion , Viljoen Albertus , Dufrêne Yves F.
Published: May 2021

We use a novel platform combining force-clamp spectroscopy with a fluorescence-based piliated cell selection to study the nanomechanics and dynamics of the retraction of the Caulobacter crescentus Tad pilus.
Synergy between copper and iron sites inside carbon nanofibers for superior electrocatalytic denitrification
Authors: Lan Yue , Luo Hongxia , Ma Yuanyuan , Hua Yilong , Liao Ting , Yang Jianping
Published: May 2021

Bimetal Cu/Fe nanoparticles encased in N-doped carbon nanofibers achieved the high-efficiency reduction of nitrate, as well as a nitrate conversion rate of 76%, nitrate removal capacity of 5686 mg N g−1 Cu/Fe and nitrogen selectivity of 94% for 24 h.
Tuning the exchange dynamics of boronic acid hydrazones and oximes with pH and redox control
Authors: Han Gun Su , Domaille Dylan W.
Published: May 2021

Hydrazones and oximes with proximal boronic acids undergo facile exchange, which can be sped up or slowed down with pH control or abolished with oxidation.
A hydrogen evolution catalyst lowering energy consumption in aluminum anodization
Authors: Li Xiang , Du Xianfeng , Huang Shan , Xiong Lilong
Published: May 2021

Aluminum anodization process requires a lot of electrical energy for the migration of ions in a barrier-type oxide film, in which electrode polarization leads to massive energy consumption.
Bioactive engineered photothermal nanomaterials: from theoretical understanding to cutting-edge application strategies in anti-cancer therapy
Authors: Gao Fucheng , Sun Zhiwei , Zhao Li , Chen Fan , Stenzel Martina , Wang Fenglong , Li Hui , Zhang Lin , Jiang Yanyan
Published: May 2021

In this paper, the photothermal conversion principles and the latest application strategies in photothermal therapy of nanomaterials are generalized. Finally, the suggestions for further development of them in anti-cancer therapy are given.
A transient high-energy surface powered by a chemical fuel
Authors: Zhuang Yuandi , Zhou Fengxiang , Ye Gaojun , Tu Mei , Jiang Lingxiang
Published: May 2021

The authors leverage nonequilibrium chemistry to shape the temporal profile of surface tension in an aqueous system.
Visible-light mediated cascade cyclization of ene-vinylidenecyclopropanes: access to fluorinated heterocyclic compounds
Authors: Meng Zhe , Zhang Xiaoyu , Shi Min
Published: May 2021

A visible-light mediated fluorinated cyclization of ene-vinylidenecyclopropanes along with mechanistic investigations is presented.
Formation of self-assembled Gd2O3nanowire-like structures during epitaxial growth on Si(001)
Authors: Gribisch Philipp , Fissel Andreas
Published: May 2021

The formation of nanowire-like structures during epitaxial growth of Gd2O3on Si(001) at high temperatures is investigated. The results are discussed by means of physical models.
Synthesis and antioxidant activities of berberine 9-O-benzoic acid derivatives
Authors: Liu Yanfei , Long Shuo , Zhang Shanshan , Tan Yifu , Wang Ting , Wu Yuwei , Jiang Ting , Liu Xiaoqin , Peng Dongming , Liu Zhenbao
Published: May 2021

Although berberine (BBR) shows antioxidant activity, its activity is limited.
A label-free electrochemical biosensor based on 3D cubic Eu3+/Cu2O nanostructures with clover-like faces for the determination of anticancer drug cytarabine
Authors: Foroughi Mohammad Mehdi , Jahani Shohreh , Aramesh-Broujeni Zahra , Rostaminasab Dolatabad Meisam
Published: May 2021

Electrochemical biosensor based on three-dimensional (3D) cubic of Eu3+/Cu2O with clover-like face nano-structures and ds-DNA modified carbon paste electrode for detecting cytarabine was fabricated.
Influence of fluorinated graphene-modified epoxy coatings on the corrosion behaviour of 2024 aluminium alloy
Authors: Zhao Shixiong , Dou Baojie , Duan Song , Lin Xiuzhou , Zhang Yingjun , Emori Wilfred , Gao Xiulei , Fang Zhiwen
Published: May 2021

This study provides an enhanced corrosion resistance of epoxy resin (EP) by embedding fluorinated graphene (FG) into the epoxy matrix.
Thermal, ferroelastic, and structural properties near phase transitions of organic–inorganic perovskite type [NH3(CH2)3NH3]CdBr4 crystals
Authors: Lim Ae Ran
Published: May 2021

We studied the thermal behavior and structural dynamics of [NH3(CH2)3NH3]CdBr4 near phase transition temperatures.
Polymerization of a biscalix[5]arene derivative
Authors: Hirao Takehiro , Fukuta Kazushi , Haino Takeharu
Published: May 2021

A calix[5]arene appended monomer molecule was subjected to polymerization reaction to yield corresponding methacrylate polymers. The calix[5]arene appended polymers showed excellent encapsulation capability for fullerene molecules.
Preparation of a stabilized aqueous polystyrene suspensionviaphase inversion
Authors: Dastbaz Zahra , Dana Shabnam Nargesi , Ashrafizadeh Seyed Nezameddin
Published: May 2021

The phase inversion emulsification method was used to prepare polystyrene aqueous suspensions. Final suspensions were characterized to determine the most stable suspension.
Transparent and flexible ZnO nanorods induced by thermal dissipation annealing without polymer substrate deformation for next-generation wearable devices
Authors: Kim Dongwan , Leem Jae-Young
Published: May 2021

A transparent and flexible ultraviolet (UV) photodetector based on ZnO nanorods grown onto the thermal dissipation annealed ZnO seed layer exhibited high photosensitivity, photoresponsivity, and photocurrent stability without substrate deformation.
Removal of per- and polyfluoroalkyl substances (PFAS) from water by ceric(iv) ammonium nitrate
Authors: Sun Jun , Jennepalli Sreenu , Lee Matthew , O'Carroll Denis M. , Åkermark Björn , Manefield Michael J. , Das Biswanath , Kumar Naresh
Published: May 2021

Removing per- and polyfluoroalkyl substances (PFASs) from water by ceric ammonium nitrate (CAN).
The inorganic cation-tailored “trapdoor” effect of silicoaluminophosphate zeolite for highly selective CO2 separation
Authors: Wang Xiaohe , Yan Nana , Xie Miao , Liu Puxu , Bai Pu , Su Haopeng , Wang Binyu , Wang Yunzheng , Li Libo , Cheng Tao , Guo Peng , Yan Wenfu , Yu Jihong
Published: May 2021

The sodium form of silicoaluminophosphate RHO zeolite exhibits a pronounced cation-tailored “trapdoor” effect, showing an unprecedented selectivity adsorption separation performance for CO2/CH4 and CO2/N2.
Beyond structural motifs: the frontier of actinide-containing metal–organic frameworks
Authors: Martin Corey R. , Leith Gabrielle A. , Shustova Natalia B.
Published: May 2021

This perspective deviates from exclusively focusing on structural features of actinide-containing metal-organic frameworks and pivots towards their prospect as avant-garde materials with an emphasis on their physicochemical properties.
Polyamide amine/aramid nanofiber composite aerogels as an ultra-high capacity adsorbent for Congo red removal
Authors: He Zhichao , Wu Fan , Guan Shengjie , Liu Li , Li Jun , Huang Yudong
Published: May 2021

An ultrahigh adsorption capacity adsorbent was prepared through facile blending of polyamide amine dendrimers into aramid nanofibers, due to the increased specific surface area and changed adsorption mechanism.
Refined band structure plus enhanced phonon scattering realizes thermoelectric performance optimization in CuI–Mn codoped SnTe
Authors: Wu Gang , Guo Zhe , Zhang Qiang , Wang Xuemei , Chen Lidong , Tan Xiaojian , Sun Peng , Liu Guo-Qiang , Yu Bo , Jiang Jun
Published: May 2021

CuI–Mn codoping promotes valence band convergence and enhances multiple defect-phonon scattering in SnTe, giving rise to significantly improved thermoelectric performance.
Bringing naturally-occurring saturated fatty acids into biomedical research
Authors: Xue Ke , Lv Shuyi , Zhu Chunlei
Published: May 2021

This review introduces naturally-occurring saturated fatty acids (NSFAs) and their biomedical applications, including controlled drug release, targeted drug delivery, cancer therapy, antibacterial treatment, and tissue engineering.
Boosting the humidity resistance of nonconventional luminogens with room temperature phosphorescence via enhancing the strength of hydrogen bonds
Authors: Meng Yide , Guo Song , Jiang Bingli , Zhang Xiaofeng , Zou Linmin , Wei Chun , Gong Yongyang , Wu Si , Liu Yuanli
Published: May 2021

A rational principle for designing nonconventional RTP luminogens with excellent humidity resistance through H-bond engineering was presented.
Out-of-equilibrium lattice response to photo-induced charge-transfer in a MnFe Prussian blue analogue
Authors: Azzolina G. , Bertoni R. , Mariette C. , Cammarata M. , Trzop E. , Ecolivet C. , Sander M. , Levantino M. , Tokoro H. , Imoto K. , Yoshikiyo M. , Ohkoshi S. , Collet E.
Published: May 2021

Photo-induced charge-transfer in the RbMnFe Prussian blue analogue is coupled to a Jahn–Teller distortion, which results in an anisotropic crystalline lattice reorganization.
Optimizing the energy levels and crystallinity of 2,2′-bithiophene-3,3′-dicarboximide-based polymer donors for high-performance non-fullerene organic solar cells
Authors: Tang Yi , Xie Lan , Qiu Dingding , Yang Chen , Liu Yanan , Shi Yanan , Huang Ziyun , Zhang Jianqi , Hu Jiawen , Lu Kun , Wei Zhixiang
Published: May 2021

BTI-based polymer donors greatly affect the active layer morphology by adjusting energy levels and crystallinity, so as to optimize the phase separation, which is important for the construction and development of organic solar cells.
Identification of potential core genes and pathways predicting pathogenesis in head and neck squamous cell carcinoma
Authors: Wang Mengmeng , Zhong Bin , Li Man , Wang Yanjuan , Yang Huaian , Du Ke
Published: May 2021

Head and neck squamous cell carcinoma (HNSCC) is the most common subtype of head and neck cancer; however, its pathogenesis and potential therapeutic targets remain largely unknown. In the present study, we analyzed three gene expression profiles and screened differentially expressed genes (DEGs) between HNSCC and normal tissues. The DEGs were subjected to gene ontology (GO), Kyoto encyclopedia of genes and genomes (KEGG), protein–protein interaction (PPI), and survival analyses, while the connectivity map (CMap) database was used to predict candidate small molecules that may reverse the biological state of HNSCC. Finally, we measured the expression of the most relevant core gene in vitro and examined the effect of the top predicted potential drug against the proliferation of HNSCC cell lines. Among the 208 DEGs and ten hub genes identified, CDK1 and CDC45 were associated with unfavorable HNSCC prognosis, and three potential small molecule drugs for treating HNSCC were identified. Increased CDK1 expression was confirmed in HNSCC cells, and menadione, the top predicted potential drug, exerted significant inhibitory effects against HNSCC cell proliferation and markedly reversed CDK1 expression. Together, the findings of the present study suggest that the ten hub genes and pathways identified may be closely related to HNSCC pathogenesis. In particular, CDK1 and CDC45 overexpression could be reliable biomarkers for predicting unfavorable prognosis in patients with HNSCC, while the new candidate small molecules identified by CMap analysis provide new avenues for the development of potential drugs to treat HNSCC.
Distributed control of mobile robots in an environment with static obstacles
Authors: Giannousakis Konstantinos , Tzes Anthony
Published: May 2021

This study addresses the problem of deploying a group of mobile robots over a non‐convex region with obstacles. Assuming that the robots are equipped with omnidirectional range sensors of common radius, disjoint subsets of the sensed area are assigned to the robots. These proximity‐based subsets are calculated using the visibility notion, where the cell of each robot is treated as an opaque obstacle for the other robots. Based on that, optimal spatially distributed coordination algorithms are derived for the area coverage problem and for the homing problem, where the swarm needs to move to specific locations. Experimental studies demonstrate the results.
Proposal of layered mental healthcare for mental well‐being
Authors: Kiguchi Masashi , Sutoko Stephanie , Atsumori Hirokazu , Nishimura Ayako , Obata Akiko , Funane Tsukasa , Nakagawa Hiromitsu , Egi Masashi , Kuriyama Hiroyuki
Published: May 2021

A new concept, ‘Layered mental healthcare’ for keeping employees mental well‐being in the workplace to avoid losses caused by both absenteeism and presenteeism is proposed. A key factor forming the basis of the concept is the biometric measurements over three layers, i.e., behaviour, physiology, and brain layers, for monitoring mental/distress conditions of employees. Here, the necessity of measurements in three layers was validated by the data‐driven approach using the preliminary dataset measured in the office environment. Biometric measurements were supported by an activity tracker, a PC logger, and the optical topography; mental/distress conditions were quantified by the brief job stress questionnaire. The biometric features obtained 1 week before the measurement of mental/distress scores were selected for the best regression model. The feature importance of each layer was obtained in the learning process of the best model using the light graded boosting machine and was compared between layers. The ratio of feature importance of behaviour:physiology:brain layers was found to be 4:3:3. The study results suggest the contribution and necessity of the three‐layer features in predicting mental/distress scores.
A deep sequence‐to‐sequence method for accurate long landing prediction based on flight data
Authors: Kang Zongwei , Shang Jiaxing , Feng Yong , Zheng Linjiang , Wang Qixing , Sun Hong , Qiang Baohua , Liu Zhen
Published: May 2021

In civil aviation industry, runway overrun is a typical landing safety incident concerned by both airlines and authorities. Among various contributing factors to the runway overrun incident, long landing plays an important role. However, existing studies for long landing prediction mainly depend on classic machine learning methods and handcrafted features. As a result, they usually require much expert knowledge and provide unsatisfactory results. To address these problems, this paper proposes an innovative deep sequence‐to‐sequence model which utilizes QAR (Quick Access Recorder) data for accurate long landing pre‐ diction. Specifically, to cope with the high heterogeneity of QAR dataset, a data pre‐processing procedure is first proposed which includes data cleaning, interpolation and normalization steps. Second, to avoid the noises incurred by too many QAR parameters and relieve the reliance on expert experience, the GBDT (gradient boosting decision trees) model is employed to choose the most relevant parameters as features. Then a CNN‐LSTM and TG‐attention encoder‐decoder architecture is proposed to accurately predict future aircraft ground speed and radio height sequences, based on which the touchdown distance can be finally calculated. Experimental results on a large QAR dataset with 44,176 A321 flights validate effectiveness of the proposed method.
A facile non‐hydrogenated method for fabrication of black TiO2‐x/bacterial cellulose composites with improved photocatalytic performance
Authors: Qu Xiao , Lin Jianbin , Wei Feng , Sun Dongping
Published: May 2021

Black titanium dioxide (TiO2‐x) has attracted extensive attention owing to its visible light absorption and superior photodegradation activity. Here, black TiO2‐x nanocomposites are fabricated via a two‐step method followed by a heat treatment process under an argon atmosphere, and then the black TiO2‐x is loaded onto the bacterial cellulose surface by surface grafting. The presence of Ti3+ species and oxygen vacancies is proved by XPS characterisation. Furthermore, the black TiO2‐x exhibits excellent photocatalytic activity for pollutants degradation.
Simulation of a blue‐phase liquid crystal cell using a multi‐angle director model
Authors: Yang Chun‐Ying , Chang Shao‐Hua , Chen Tien‐Jung , Wu Jin‐Jei
Published: May 2021

A multi‐angle director model is proposed to simulate and interpret the electro‐optical characteristics of a blue‐phase liquid crystal (BPLC) cell driven by vertical and horizontal electric fields. Instead of employing the Kerr effect, the BPLC cell is considered as a stack of several high‐pretilt nematic liquid crystal layers that can be simulated using the director model. Simulations are performed based on the director model and results are compared with those obtained with Kerr‐effect‐based methods. The theoretical model successfully simulated the electro‐optical characteristics of the BPLC, consistent with experimental data. Hence, the model is expected to aid the design of next‐generation BPLC displays.
Tuning the electronic and optical properties of the sphalerite by adsorbing halogen and alkali metals
Authors: Tyagi Mohit , Choudhary Sudhanshu
Published: May 2021

TThe electronic and optical properties of sphalerite (ZnS) are modulated by adsorbing alkali metals (Li, Na, K, Rb, Cs) and halogen (F, Cl, Br, I, At). Simulations based on density‐functional theory are used to study the electronic and optical properties of pristine sphalerite and alkali‐halogen adsorbed sphalerite structures. The results suggest that pristine sphalerite has high absorption in several portions of ultraviolet (UV) region (λ < 250 nm) and negligible absorption in the visible and IR region. The alkali‐halogen adsorbed structure of sphalerite results into red‐shift phenomenon in which an increase in absorption coefficient with wavelength is observed or spectrum shifting towards the red end is observed. Strong absorption for both alkali and halogen adsorbed nanostructures is found throughout the visible zone (~410 to 780 nm) of the spectrum. Bromine adsorbed sphalerite structure results in highest value of absorption in visible region in comparison to other alkali and halogen adsorbed structures. This shift in absorption peaks from UV region to desired visible region range is beneficial for optoelectronic applications and in fabrication of optoelectronics devices such as LED, ARC, solar cells, CRTs and sensors.
A switching capacitor based multi‐port bidirectional DC–DC converter
Authors: Shayeghi Hossein , Pourjafar Saeed , Hashemzadeh Seyed Majid
Published: May 2021

This paper introduces a novel bidirectional multi‐port DC–DC converter recommended for electric vehicle applications. The proposed structure has three ports with bidirectional features which can be operated in both step‐up and step‐down modes. This converter can supply the load from two independent voltage sources and can obtain a high voltage conversion ratio in both step‐up and step‐down operations. The low voltage stress throughout the power switches, high efficiency, and low components count are the characteristics of the proposed topology. For demonstrating the proposed structure's performance, the principle of operation modes, steady‐state analysis, and comparison results with other similar works are provided. Finally, an experimental prototype is built with a 120 W power level at 50 kHz operating, which validates the suggested converter's effectiveness and bidirectional trait. The suggested converter's efficiency in boost and buck mode is obtained about 94.2% and 94.37%, respectively that makes this converter to be used in renewable energy systems and electric vehicles with hybrid energy sources.
Modelling and optimization of SiC MOSFET switching voltage and current overshoots in a half‐bridge configuration
Authors: Wang Lina , Ma Haobo , Qiu Hongcheng , Yuan Kai , Liu Zhuang , Cao Guoen
Published: May 2021

Due to the high‐speed switching, the switching process of a silicon carbide (SiC) metal oxide field effect transistor (MOSFET) in a practical circuit is susceptible to parasitics and exhibits significant current and voltage overshoots. This may subsequently lower the efficiency of the device, degrade the reliability of the system, increase the level of electromagnetic interference and prohibit the full utilization of SiC MOSFETs’ potential. Conventional qualitative analysis is difficult to support enough guidance to deal with the switching overshoots in practice. In order to implement quantitative analysis of the switching overshoots of SiC power electronic circuits, an analytical model of SiC MOSFET switching behaviour in the half‐bridge configuration was derived considering all important parasitic parameters, the non‐linear characteristics of the parasitic capacitances and the transconductance coefficient of the device. Based on the derived analytical model, the switching voltage and current overshoots under the specific circuit parameter conditions can be quantitatively evaluated without complex system‐level modelling. Sensitivity analysis for the voltage and current overshoots during the switching transient was quantified. Moreover, the effect rule of the gate resistance on the voltage overshoot was revealed. In the article, simulation and experimental results validate the analytical model and analysis results.
A novel secondary code acquisition algorithm for the BDS‐3 B1C signal
Authors: Qiu Tongsheng , Wang Xianyi , du Qifei , Sun Yueqiang , Wang Zhuoyan
Published: May 2021

The BDS‐3 recently started broadcasting a new civil B1C signal to provide open services for global users, which brings benefits to GNSS‐based applications. The BDS‐3 B1C signal modulates a long secondary code on the primary code in the pilot component, and it is useful to acquire the secondary code so as to extend coherent integration time when acquiring weak BDS‐3 B1C signals. However, the long secondary code of the BDS‐3 B1C signal puts FFT‐based and multi‐hypothesis‐based secondary code acquisition methods in trouble from the high computational burden. Therefore, the authors propose a novel secondary code acquisition algorithm called the partial correlation method (PCM) for the BDS‐3 B1C signal. The PCM acquires the secondary code in three steps to reduce the complexity and acquisition time, and it supports up to coherent integration and can be applied for the case of , which satisfies most cases. Further, a matched‐filter‐based architecture of the PCM is presented. Additionally, the characteristic length vector to determine the secondary code chip position quickly is proposed, which is better than the existing characteristic length method. Finally, experimental results based on real BDS‐3 B1C signals data show that the proposed PCM is effective.
Securing Endotracheal Tube in Pediatric Neurosurgical Patients Operated in Prone Position—A Novel Technique
Authors: Kalra Samir Kumar ,   Rajkumar
Published: May 2021

Introduction The purpose of the present study relates to prevention of accidental extubation (AE) of pediatric patients in prone position. The control of endotracheal tube (ETT) in prone position becomes very difficult and an AE often occurs. This is more so deleterious in this age group because of the shallow respiratory reserves in children as well as the common use of noncuffed endotracheal tubes. The accidental tube exit may be a life-threatening event and its prevention is extremely important.

Case Description Using the used plastic bottle of intravenous fluids, a rectangular piece is cut, foam pasted and wrapped on itself and stout threads are attached. This attachment is used for securing the ETT by wrapping it. The technical details are described in the text. The AE is a potentially disastrous event and its occurrence in pediatric patients is even more dangerous. Many techniques have been developed over the years for prevention of such an event.

Conclusions The present technique uses all the principles of ETT fixation without leading to adding any significant technical difficulties. The method is safe, cost-effective and easily reproducible way of securement of ETT in pediatric neurosurgical patients operated in the prone position.
Skull Base Angle Morphometry in South Indian Population with Review on Terminology
Authors: Raveendranath Veeramani , Dash Prafulla Kumar , Nagarajan Krishnan , Kavitha Thangaraj , Swathi Srinidhi
Published: May 2021

Introduction Basal angle, Boogaard’s angle, and clival angle are frequently used in diagnosing the craniometric angle malformations either on radiography or now more on MRI. But anatomic and clinical studies have used varied terms for these parameters. We aimed to look for these parameters among a normal south Indian adult population to standardize the measurements and their terminology.

Materials and Methods One hundred MRI images (50 males and 50 female) were studied retrospectively. MRI images that were reported as normal by neuroradiologist were taken up for the study. Mean and the standard deviation of males and females were calculated for basal angle, Boogaard’s angle, and clival angle, separately. Unpaired t-test was used to analyze the significant difference (p < 0.05) between the genders. The intraclass coefficient correlation was used to analyze the interobserver variability.

Results The mean value of basal angle in males and females are 113°and 114°, respectively. The mean value of Boogaard’s angle in males and females are 120°and 121°, respectively. The mean value of clival angle in males and females are 157°and 155°, respectively. There was no statistically significant difference (p > 0.05) between males and females in all three angles.

Conclusion Knowledge about the normal angles will be an important tool in understanding the normal and abnormal skull base. Since the type of skull varies in accordance with race, the normal craniometric angle also varies in accordance with race. The present study tried to standardize the parameters of normal skull base angles for appropriate correction of the anomalies and uniform usage of terminology.
Genome editing and ‘disenhancement’: Considerations on issues of non-identity and genetic pluralism
Authors: Feeney Oliver , Rakić Vojin
Published: May 2021

In the decade prior to CRISPR-Cas9, Michael Parker criticised Julian Savulescu’s Procreative Beneficence (PB) Principle by arguing against the confidence to know what’s best in terms of genetic traits for our offspring. One important outcome of this criticism was a greater moral acceptance of deaf people genetically selecting deaf children. Although this outcome may have been morally controversial in an impersonal harm context, in such genetic selection (PGD) cases, a deaf child is not harmed in person-affecting terms because no other life is available to that child. We highlight that the person-affecting versus impersonal harm distinction is still held by many as making a significant moral difference to their overall argument (i.e. Savulescu, Parker, Boardman, De Miguel Beriain) and so for the purposes of this paper, we will assume it makes ‘some difference’ (even if only at the level of the message it sends out). Insofar as one considers the presence person-affecting harm to be morally important (and to whatever extent), the impersonal harm context in which the Parker–Savulescu debate arose thereby blunts an arguably even more radical outcome—that of genetically engineering, or gene editing, deafness into pre-existing embryos of future children. Now, the potential of CRISPR-Cas9 has revitalised such debates by reframing impersonal and person-affecting benefits/harms in the context of such disputes on the harm or not of a (chosen) disability. Replacing the genetic selection context with a genome editing context, we argue that Parker’s argument should also deem it morally acceptable for people who are deaf to genetically edit embryos to become children who are also deaf. Felicity Boardman’s recent comments suggest a similar radical potential as Parker’s, with the radicalness also blunted by an impersonal context (a context that Boardman, at least, sees as significant). We conclude that the genome editing reframing will push such arguments beyond what were originally intended, and this will create a more radical message that may help further define the relationship between new genomic technologies and disability.
Metallic carbon nanotube quantum dots with broken symmetries as a platform for tunable terahertz detection
Authors: Buchs G. , Marganska M. , González J. W. , Eimre K. , Pignedoli C. A. , Passerone D. , Ayuela A. , Gröning O. , Bercioux D.
Published: May 2021

Generating and detecting radiation in the technologically relevant range of the so-called terahertz gap (0.1–10 THz) is challenging because of a lack of efficient sources and detectors. Quantum dots in carbon nanotubes have shown great potential to build sensitive terahertz detectors, usually based on photon-assisted tunneling. A recently reported mechanism combining resonant quantum dot transitions and tunneling barrier asymmetries results in a narrow linewidth photocurrent response with a large signal-to-noise ratio under weak THz radiation. That device was sensitive to one frequency, corresponding to transitions between equidistant quantized states. In this work we show, using numerical simulations together with scanning tunneling spectroscopy studies of a defect-induced metallic zigzag single-walled carbon nanotube quantum dot, that breaking simultaneously various symmetries in metallic nanotube quantum dots of arbitrary chirality strongly relaxes the selection rules in the electric dipole approximation and removes energy degeneracies. This leads to a richer set of allowed optical transitions spanning frequencies from 1 THz to several tens of THz, for a ∼10 nm quantum dot. Based on these findings, we propose a terahertz detector device based on a metallic single-walled carbon nanotube quantum dot defined by artificial defects. Depending on its length and contacts transparency, the operating regimes range from a high-resolution gate-tunable terahertz sensor to a broadband terahertz detector. Our calculations indicate that the device is largely unaffected by temperatures up to 100 K, making carbon nanotube quantum dots with broken symmetries a promising platform to design tunable terahertz detectors that could operate at liquid nitrogen temperatures.
Thermoelectric properties study on the BN nanoribbons via BoltzTrap first-principles
Authors: Jiang Xiangqian , Ban Chuncheng , Li Ling , Wang Chong , Chen Weiping , Liu Xiaowei
Published: May 2021

Thermoelectric materials have attracted the attention of scientists because they directly convert waste heat of electric energy into valuable electrical energy. In recent years, the boron nitride structure has attracted much attention due to its thermoelectric properties and environmental friendliness. In this paper, the thermoelectric properties of boron nitride nanoribbons were simulated and analyzed, discovering that the figure-of-merit (ZT) value of armchair boron nitride nanoribbons is much better than that of zigzag boron nitride nanoribbons. Subsequently, we discuss the bandwidth effects and edge chirality on two important thermoelectric properties, Seebeck coefficient and ZT. Although edge passivation has been carried out, different edge chiralities still have a significant impact on carrier transport. The development of boron nitride-based materials will clarify their potential for developing high performance next generation thermoelectric devices.
Effects of inflow boundary layer on the wake of a radially non-uniform porous disk
Authors: Abdulrahim Anas , Akpolat M. Tuğrul , Hassanein Abdelrahman , Perçin Mustafa , Uzol Oğuz
Published: May 2021

This study presents the results of an experimental investigation focusing on the effects of the inflow boundary layer on the wake characteristics of a 0.12 m diameter porous disk with radially non-uniform porosity in terms of mean flow, turbulence, and wake scaling. Two-dimensional two-component particle image velocimetry measurements within the wake are performed up to 7.5 diameters downstream as the disk is lowered deeper into a boundary layer that is representative of a neutral atmospheric boundary layer over a flat terrain. Results show that otherwise symmetrical wake velocity profiles that exist outside the boundary layer get skewed and sheared around the disk centerline in the boundary layer due to the inflow wind shear. The turbulent kinetic energy, its production, and Reynolds shear stress levels in the wake get asymmetrical around the centerline of the disk such that the production of turbulent kinetic energy is observed to be higher above centerline. Due to the inflow shear, the wake centerline gets shifted downwards (i.e., toward the wind tunnel wall), which is in contrast to the observations on real wind turbine wakes in the literature where the wake actually lifts up. The asymmetrical and skewed velocity profiles both in the streamwise and cross-stream directions can be collapsed onto a single function by using proper wake scaling parameters based on the ratio of local strain to average strain within the velocity profile calculated separately for either side of the wake.
Multitemperature parameter optimization for fused deposition modeling based on response surface methodology
Authors: Wang Zhi , Li Jing , Wu Wenjie , Zhang Daijun , Yu Ning
Published: May 2021

Fused deposition modeling (FDM) is an additive manufacturing technology that is extensively applied in engineering and medicine and offers a wide range of raw materials, low manufacturing cost, and personalized features. The mechanical properties of parts fabricated by FDM are greatly influenced by the multitemperature process parameter system. However, systematic research on the relationship between the multitemperature parameter system and mechanical properties of FDM parts is lacking. In this study, we used the response surface methodology (RSM) to optimize a multi-temperature parameter system of FDM to address the limitations of the commonly used conventional experimental method. The effect of temperature conditions (nozzle temperature, platform temperature, and environment temperature) on the tensile strength of the carbon fibers/polylactic acid composite specimens was systematically studied using the constructed RSM model. The RSM model was used to analyze and optimize the parameters of the multitemperature system for the optimal tensile strength, and the FDM experiment was carried out. The tensile strengths obtained using the FDM and response surface optimization were 32.4 and 31.35 MPa, respectively, with a gap of 3.2%. These results show that the RSM optimization method has a remarkable effect and can be used to optimize the multitemperature parameter system of the FDM.
Stochastic model updating considering thermal effect using perturbation and improved support vector regression
Authors: Chen Zhe , He Huan , Zhao Qi-jun
Published: May 2021

The dynamic modeling of structures in a thermal environment has become a new research topic in structural dynamics. Uncertainties caused by noise or material variability increase the difficulty in structural dynamic modeling when considering thermal effects. In this study, a finite element (FE) model updating approach is proposed that includes thermal effects and uncertainties by using a hierarchical strategy. First, the dynamic problem of a structure in a thermal environment is classified into a thermal model and a structural dynamic model, and they are both constructed by using the FE method. As a result, the model updating process is conducted for both the thermal model and structural dynamic model. Different from other works about model updating methods, the updating variables, which are composed of the mechanical characteristics and thermal parameters of the system, are dominated by the temperature distribution of the structure under study. A perturbation method and a surrogate model are adopted in the stochastic model updating approach to make the updating process highly efficient. Finally, the proposed method is validated by updating the model of a fuselage skin and a bolt connection beam in a thermal environment.
Policy and weather influences on mobility during the early US COVID-19 pandemic
Authors: Wu Yihan , Mooring Todd A. , Linz Marianna
Published: May 2021

Significance

This study investigates mobility changes during the first major quarantine period in response to the COVID-19 pandemic in the United States, assessing how human behavior changed in response to policies and to weather. Through mobility metrics based on tracking mobile devices, we show that consistent national behavioral change was associated with clear national messaging and independent of local policy. While the number of park visitations changed with weather conditions, generally, the changes apparently did not increase potential encounters between people. The independence of encounters and temperatures suggests that, if these results hold in the future, behavioral responses to short-term temperature variations may have, at most, a limited impact relative to any direct physical modulation of transmission by weather as the virus becomes endemic.
An emulator for the Lyman-α forest in beyond-ΛCDM cosmologies
Authors: Pedersen Christian , Font-Ribera Andreu , Rogers Keir K. , McDonald Patrick , Peiris Hiranya V. , Pontzen Andrew , Slosar Anže
Published: May 2021

Interpreting observations of the Lyman-α forest flux power spectrum
requires interpolation between a small number of expensive simulations.
We present a Gaussian process emulator modelling the 1D flux power spectrum as
a function of the amplitude and slope of the small-scale linear matter power
spectrum, and the state of the intergalactic medium at the epoch of interest
(2 < z < 4).
This parameterisation enables the prediction of the flux power spectrum in
extended cosmological models that are not explicitly included in the training set,
eliminating the need to construct bespoke emulators for a number of extensions
to ΛCDM.
Our emulator is appropriate for cosmologies in which the linear matter power
spectrum is described to percent level accuracy by just an amplitude and
slope across the epoch of interest, and in the regime probed by eBOSS/DESI data.
We demonstrate this for massive neutrino cosmologies, where the emulator is able
to predict the flux power spectrum in a Σ mν=0.3 eV neutrino cosmology
to sub-percent accuracy, without including massive neutrinos in the training simulations.
Further parameters would be required to describe models with sharp features in the
linear power, such as warm or light axion dark matter.
This work will facilitate the combination of upcoming DESI data
with observations of the
cosmic microwave background, to obtain constraints on neutrino mass and
other extensions to ΛCDM cosmology.
High spin states in 71Ga *
Authors: Zhong Jian , Deng Li-Tao , Hu Shi-Peng , Wu Xiao-Guang , Srivastava P. C. , Saxena A. , Li Guang-Sheng , Zheng Yun , Li Cong-Bo , Chen Qi-Ming , He Chuang-Ye , Zhou Wen-Kui , Zhu Bao-Ji , Fang Qi-Wen , Hua Hui , Sun Jun-Jie , Sun Hui-Bin , Gan Lin , Zhao Hai-Ge , Luo Qi , Wu Zheng-Xin
Published: May 2021

Excited states in the odd-A nucleus 71Ga have been studied via the 70Zn(7Li,

)71Ga fusion-evaporation reaction with incident beam energies of 30 and 35 MeV. The level scheme is established up to spin

= (29/2+) and an excitation energy

6.6 MeV. A previously known sequence built on the 9/2+ state is extended as a novel rotational band originating from the

alignment. Furthermore, a negative-parity sequence is also reported. The observed energy levels of 71Ga have been interpreted in the framework of the nuclear shell model (SM).
Small shower CORSIKA simulations
Authors: Wibig Tadeusz
Published: May 2021

Extensive Air Showers (EAS) induced by cosmic ray particles of very low energies, owing to the significantly steep cosmic ray energy spectrum, dominate the secondary particle flux measured by single detectors and small shower arrays. Such arrays connected in extended networks can be used to determine potentially interesting spatial correlations between showers, which may shed new light on the nature of ultra high-energy cosmic rays. The quantitative interpretation of showers recorded by small local arrays requires a methodology that differs from that used by ordinary large EAS arrays operating in the "knee" region and above. We present "small EAS generator," a semi-analytical method for integrating cosmic ray spectra over energies of interest and summing over the mass spectra of primary nuclei in arbitrary detector configurations. Furthermore, we provide results on the EAS electron and muon fluxes and particle density spectra.