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The functional significance of residual yolk in lizards

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Current Zoology 2023年第2期69卷 192-199页

作者： Kun Guo cai-feng wang Yu Du Yan-Fu Qu Florentino Brana Xiang Ji Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection College of Life and Environmental SciencesWenzhou UniversityWenzhou 325035ZhejiangChina Hainan Key Laboratory of Herpetological Research College of Fisheries and Life ScienceHainan Tropical Ocean UniversitySanya 572022HainanChina College of Life Sciences Nanjing Normal UniversityNanjing 210023China Departamento de Biologia de Orgar smos v Sistemas.Universidad de 0viedo Oviedo 33071Spain

Residual yolk is assumed to be an important source of energy and nutrients during early life in nonmammalian amniotes.Available data show that the mean size of residual yolk is far smaller in lizards than in turtles,snakes,crocodiles,and birds,raising a question of whether residual yolk is of functional significance in lizards.Here,we compared data from 26 lizard species with those from other nonmammalian amniotes to test the hypothesis that residual yolk is functionally less significant in species producing more fully developed offspring.In our sample,species mean offspring water contents ranged from 73%to 84%of body wet mass;species mean proportions of carcass dry mass,fat-body dry mass,and residual yolk dry mass to offspring dry mass ranged from 84%to 99%,0%to 5.0%,and 0%to 14.4%,respectively.Lizards are,on average,more fully developed at hatching or birth than snakes,as revealed by the fact that the mean proportion of carcass dry mass to body dry mass and offspring water contents were both higher in lizards than in snakes.We conclude that the functional significance of residual yolk during early life is generally less evident in lizards.Even in the lizards where residual yolk is of potential functional significance,this portion of yolk contributes little,if any,to postembryonic growth.Future work could usefully collect data across a wider spectrum of reptile taxa to establish a precocial-altricial continuum and test the hypothesis that species with a smaller amount of residual yolk are closer to the precocial end of the continuum.

关键词： carcass fatbody lizards offspring postembryonicgrowth residual yolk

Stochastic Volatility Modeling based on Doubly Truncated Cauchy Distribution and Bayesian Estimation for Chinese Stock Market

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应用数学学报:英文版 2023年第4期39卷 791-807页

作者： cai-feng wang Cong XIE Zi-yu MA Hui-min ZHAO School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China School of Business Sun Yat-sen UniversityGuangzhou 510275China

In order to measure the uncertainty of financial asset returns in the stock market, this paper presents a new model, called SV-dt C model, a stochastic volatility(SV) model assuming that the stock return has a doubly truncated Cauchy distribution, which takes into account the high peak and fat tail of the empirical distribution simultaneously. Under the Bayesian framework, a prior and posterior analysis for the parameters is made and Markov Chain Monte Carlo(MCMC) is used for computing the posterior estimates of the model parameters and forecasting in the empirical application of Shanghai Stock Exchange Composite Index(SSECI) with respect to the proposed SV-dt C model and two classic SV-N(SV model with Normal distribution)and SV-T(SV model with Student-t distribution) models. The empirical analysis shows that the proposed SV-dt C model has better performance by model checking, including independence test(Projection correlation test), Kolmogorov-Smirnov test(K-S test) and Q-Q plot. Additionally, deviance information criterion(DIC) also shows that the proposed model has a significant improvement in model fit over the others.

关键词： stochastic volatility model doubly truncated Cauchy distribution Bayesian estimation Markov Chain Monte Carlo method deviance information criterion

Facile synthesis,high fluorescence and flame retardancy of carbon dots

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Journal of Materials Science & Technology 2022年第9期104卷 163-171页

作者： Chang Liu Hongying Li Rui Cheng Jiazhuang Guo Guo-Xing Li Qing Li cai-feng wang Xiaoning Yang Su Chen State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringJiangsu Key Laboratory of Fine Chemicals and Functional Polymer MaterialsNanjing Tech UniversityNanjing 210009China

Facile strategy enabling the fabrication of carbon dots(CDs)with favorable performance useful for various applications is highly desirable.Here,we report the fabrication of highly fluorescent carbon dots(CDs)towards sensitive metal ion detection,brightly fluorescent printing pattern,as well as green flame retardants for synthetic polymeric materials.CDs are synthesized by solvothermal treatment of polypropylene carbonate(PPC)with ethylenediamine,and the quantum yield of CDs could increase from 30%to 86%by further adding trace of citric acid.The abundant functional groups on the surface of CDs allow CDs well incorporated into polymers to form CD-loaded polystyrene(PS)microspheres,which are employed to construct fluorescent supraballs via triphase microfluidic technique and used as“inks”for uniform fluorescent patterns.Interestingly,the resultant CDs show good flame retardancy for highly flammable polymeric foams and fibers.The CDs surpass previously reported flame-retardant additives,to show excellent combustion resistance that the addition of 20 wt%CDs causes 75%decrease in the peak of heat release rate(P-HRR)for polyurethane(PU)foams.Significantly,a molecular dynamics simulation process for PU/CDs combustion is constructed.This work may spur the preparation and application of highperformance carbon-based nanomaterials.

关键词： Carbon dots Fluorescence Flame retardancy Molecular dynamics simulation

Carbon dots embedded nanofiber films:Large-scale fabrication and enhanced mechanical properties

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Chinese Chemical Letters 2022年第1期33卷 304-307页

作者： Chang Liu Rui Cheng Jiazhuang Guo Ge Li He Li Hong-Gang Ye Zhi-Bin Liang cai-feng wang Su Chen State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical Engineeringand Jiangsu Key Laboratory of Fine Chemicals and Functional Polymer MaterialsNanjing Tech UniversityNanjing 210009China

Valuable application prospects and large-scale production technologies are powerful driving forces for the development of materials science.Carbon dots(CDs)are a kind of promising carbon-based fluorescent nanomaterials,which possess wide application prospects based and even beyond the fluorescence properties.Herein,we report the fast and high-yield synthesis of CDs and the large-scale preparation of fluorescent nanofiber films with enhanced mechanical properties.CDs were prepared from magnetic hyperthermia treatment of citric acid and carbamide,with the output of 25.37 g in a single batch.The asprepared CDs exhibit a high absolute photoluminescence(PL)quantum yield(QY)of 67%and wonderful dispersibility in polar solvents.Then,solution blow spinning of CDs and polymer matrixes of alcohol soluble polyurethane(APU)and polyacrylonitrile(PAN)led to large-area fluorescent CDs-embedded nanofiber films,APU/CDs(size:120 cm×18 cm)and PAN/CDs(size:120 cm×22 cm),respectively.The resultant large-area APU/CDs and PAN/CDs nanofiber films have dramatically enhanced mechanical properties,to show integrated improvement of tensile strength and elongation.

关键词： Carbon dots Mass production Solution blow spinning Nanofiber Mechanical properties

In-situ synthesis of stable perovskite quantum dots in core-shell nanofibers via microfluidic electrospinning

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Chinese Chemical Letters 2023年第3期34卷 518-521页

作者： Rui Cheng Zhi-Bin Liang Haixia Shen Jiazhuang Guo cai-feng wang Su Chen State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical Engineeringand Jiangsu Key Laboratory of Fine Chemicals and Functional Polymer MaterialsNanjing Tech UniversityNanjing 210009China

Perovskite quantum dots(PQDs) possess remarkable optical properties, such as tunable photoluminescence(PL) emission spectra, narrow full width at half maximum(FWHM) and high PL quantum yield(QY), endowing the PQDs great application prospects. However, the inherent structural instability of PQDs has seriously hindered the application of PQDs in various photoelectric devices. In this work, a microfluidic electrospinning method was used to fabricate color-tunable fluorescent formamidinium lead halogen(FAPbX_(3), X = Cl, Br, I) PQDs/polymer core-shell nanofiber films. The core-shell spinning nanofiber not only supplies the interspace for the in-situ formation of PQDs, but also significantly reduces the permeability of moisture and oxygen in the air, which greatly improves the stability of PQDs. After adjusting the composition of precursors, the blue-emissive polystyrene(core) and polymethyl methacrylate(shell) coated FAPbCl_(3) QDs(abbreviated as PS/FAPbCl_(3)/PMMA, hereinafter), green-emissive PS/FAPbBr_(3)/PMMA and redemissive PS/FAPbI_(3)/PMMA nanofiber films were fabricated with the highest PL QY of 82.3%. Moreover,the PS/FAPbBr_(3)/PMMA nanofiber film exhibits great PL stability under blue light irradiation, long-term storage in the air and water resistance test. Finally, the green-and red-emissive nanofiber films were directly applied as light conversion films to fabricate wide-color-gamut display with the color gamut of 125%, indicating their tremendous potentials in optoelectronic applications.

关键词： Perovskite quantum dots Microfluidic electrospinning Nanofiber PL stability Display

A Piezoelectrically Driven Microrobot Using a Novel Monolithic Spatial Parallel Mechanism as Its Hip Joint

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Journal of Bionic Engineering 2024年第2期21卷 803-820页

作者： Guangping Wu Ziyang wang Jiaxin Zhao feng Cui Xinghan cai National Key Laboratory of Advanced Micro and Nano Manufacture Technology Shanghai Jiao Tong UniversityShanghai200240China Department of Micro-Nano Electronics School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai200240China

Inspired by the fast,agile movements of insects,we present a 1.9 g,4.5 cm in length,piezoelectrically driven,quadrupedal microrobot.This microrobot uses a novel spatial parallel mechanism as its hip joint,which consists of two spatially orthogonal slider-crank linkages.This mechanism maps two inputs of two independent actuators to the decoupled swing and lift outputs of a leg,and each leg can produce the closed trajectories in the sagittal plane necessary for robot motion.Moreover,the kinematics of the transmission are analyzed,and the parameters of the flexure hinges are designed based on geometrical constraints and yield conditions.The hip joints,legs and exoskeletons are integrated into a five-layer standard laminate for monolithic fabrication which is composed of two layers of carbon fiber,two layers of acrylic adhesive and a polyimide film.The measured output force(15.97 mN)of each leg is enough to carry half of the robot’s weight,which is necessary for the robot to move successfully.It has been proven that the robot can successfully perform forward and turning motions.Compared to the microrobot fabricated with discrete components,the monolithically fabricated microrobot is more capable of maintaining the original direction of locomotion when driven by a forward signal and has a greater speed,whose maximum speed is 25.05 cm/s.

关键词： Insect-like Crawling microrobot Piezoelectric drive Parallel mechanism Monolithic fabrication

Microstructural Evolutions and Mechanical Properties of Energetic Al_(1) (TiZrNbTaMoCr)_(15) High-Entropy Alloys

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 620-632页

作者： Xuan-Hong cai Zhen-Hua wang Ben Niu Jin-feng Li Qing wang Show authors Key Laboratory of Materials Modification By Laser Ion and Electron Beams(Ministry of Education)Engineering Research Center of High Entropy Alloy Materials(Liaoning Province)School of Materials Science and EngineeringDalian University of TechnologyDalian116024China Institute of Materials China Academy of Engineering PhysicsMianyang621908China

The present study focuses on investigating the microstructural evolutions and mechanical properties of energetic Al_(1)(TiZrNbTaMoCr)_(15) refractory high-entropy alloys with the different heat treatments at low Al content state. It is found that even with a reduction in the Al content, the strength of these alloys remains unaffected at room temperature and high temperature, while the plasticity improves significantly. In particular, the coherent BCC/B_(2) microstructure with needle-like B_(2) nanoprecipitates dispersed into the BCC matrix is formed in 873 K-aged Al_(1)Ti_(6)Zr_(2)Nb_(3)Ta_(3)Mo_(0.5)Cr_(0.5) alloy. Therefore, this alloy exhibits the highest compression yield strength (σ_(YS) = 1333 and 717 MPa) at room temperature and 1073 K, respectively. After 973 K-aged, the coherent BCC/B_(2) microstructure underwent destabilization, and the B_(2) phase transforms into the brittle Zr5Al3 phase which then coarsens and dominates the microstructure of S3-AlTa_(3) alloy after 1073 K-aged. Moreover, these current alloys exhibit exceptionally high theoretical exothermic enthalpy (ΔH), surpassing 11606 J·g^(−1), which highlights their significant potential as innovative high-performance energetic structural materials.

关键词： Refractory high-entropy alloy Coherent microstructure Mechanical property Exothermic enthalpy

Two-Staged Method for Ice Channel Identification Based on Image Segmentation and Corner Point Regression

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China Ocean Engineering 2024年第2期38卷 313-325页

作者： DONG Wen-bo ZHOU Li DING Shi-feng wang Ai-ming cai Jin-yan School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Identification of the ice channel is the basic technology for developing intelligent ships in ice-covered waters,which is important to ensure the safety and economy of navigation.In the Arctic,merchant ships with low ice class often navigate in channels opened up by icebreakers.Navigation in the ice channel often depends on good maneuverability skills and abundant experience from the captain to a large extent.The ship may get stuck if steered into ice fields off the channel.Under this circumstance,it is very important to study how to identify the boundary lines of ice channels with a reliable method.In this paper,a two-staged ice channel identification method is developed based on image segmentation and corner point regression.The first stage employs the image segmentation method to extract channel regions.In the second stage,an intelligent corner regression network is proposed to extract the channel boundary lines from the channel region.A non-intelligent angle-based filtering and clustering method is proposed and compared with corner point regression network.The training and evaluation of the segmentation method and corner regression network are carried out on the synthetic and real ice channel dataset.The evaluation results show that the accuracy of the method using the corner point regression network in the second stage is achieved as high as 73.33%on the synthetic ice channel dataset and 70.66%on the real ice channel dataset,and the processing speed can reach up to 14.58frames per second.

关键词： ice channel ship navigation identification image segmentation corner point regression

An ultra-porous g-C_(3)N_(4) micro-tube coupled with MXene(Ti_(3)C_(2)TX)nanosheets for efficient degradation of organics under natural sunlight

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Journal of Environmental Sciences 2024年第3期137卷 258-270页

作者： Zongyang Ya Qiyou wang Jingjin cai Peng wang Xinyu Jiang Zhiyin cai Shanglin Xiang Tingwei wang Dongyu cai College of Materials Science&Engineering Nanjing Tech University30 South PuZhu RoadNanjing 211816China Key Laboratory of Flexible Electronics(KLOFE)&Institute of Advanced Materials(IAM) Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)Nanjing Tech University30 South PuZhu RoadNanjing 211816China

It remains as a challenge for realizing efficient photo-responsive catalysts towards largescale degradation of organic pollutants under natural sunlight.This work reports a new pore engineering strategy for creating ultra-porous g-C_(3)N_(4) micro-tubes with an unprecedentedly high specific surface area of 152.96 m^(2)/g.This is mainly associated with releasing internal vapor pressure in the autoclave where the hydrothermal treatment of the urea/melamine mixture is processed.Supported by microscopic observation,porosity measurement and spectroscopic characterization,it is found that releasing the pressure at halfway of hydrothermal process is vital for forming exfoliated rod-like precursors and the de-aggregation of these rods presents substantial benefits on the production of mesopores on g-C_(3)N_(4) microtubes during the calcination of precursors.This offers a large number of reactive sites required by photocatalytic reaction.Coupling these micro-tubes with Ti_(3)C_(2)T_(X) nanosheets via electrostatic interaction yields a 1D/2D heterojunction with a close interfacial contact.The addition of metallically conductive Ti_(3)C_(2)T_(X) nanosheets accelerates the separation between electrons and holes,and also enhances the light absorption.All these merits of structural design lead to forming a group of highly efficient catalysts demonstrating an excellent photocatalytic degradation rate of k=0.0560 min^(-1)for RhB dyes under 100 mW/cm~2 visible light radiation that micks sunlight outdoors.This laboratory valuation is further supported by an outdoor test that shows a fast degradation rate of 0.0744 min^(-1)under natural sunlight.

关键词： Carbon nitride MXene Heterojunction Photocatalysis