Fourth-order phase-field modeling for brittle fracture in piezoelectric materials

Failure analyses of piezoelectric structures and devices are of engineering and scientific significance.In this paper,a fourth-order phase-field fracture model for piezoelectric solids is developed based on the Hamilton principle.Three typical electric boundary conditions are involved in the present model to characterize the fracture behaviors in various physical situations.A staggered algorithm is used to simulate the crack propagation.The polynomial splines over hierarchical T-meshes(PHT-splines)are adopted as the basis function,which owns the C1continuity.Systematic numerical simulations are performed to study the influence of the electric boundary conditions and the applied electric field on the fracture behaviors of piezoelectric materials.The electric boundary conditions may influence crack paths and fracture loads significantly.The present research may be helpful for the reliability evaluation of the piezoelectric structure in the future applications.

Single-cell transcriptome atlas reveals spatiotemporal developmental trajectories in the basal roots of moso bamboo (Phyllostachys edulis)

Roots are essential for plant growth and development.Bamboo is a large Poaceae perennial with 1642 species worldwide.However,little is known about the transcriptional atlas that underpins root cell-type differentiation.Here,we set up a modified protocol for protoplast preparation and report single-cell transcriptomes of 14279 filtered single cells derived from the basal root tips of moso bamboo.We identified four cell types and defined new cell-type-specific marker genes for the basal root.We reconstructed the developmental trajectories of the root cap,epidermis,and ground tissues and elucidated critical factors regulating cell fate determination.According to in situ hybridization and pseudotime trajectory analysis,the root cap and epidermis originated from a common initial cell lineage,revealing the particularity of bamboo basal root development.We further identified key regulatory factors for the differentiation of these cells and indicated divergent root developmental pathways between moso bamboo and rice.Additionally,PheWOX13a and PheWOX13b ectopically expressed in Arabidopsis inhibited primary root and lateral root growth and regulated the growth and development of the root cap,which was different from WOX13 orthologs in Arabidopsis.Taken together,our results offer an important resource for investigating the mechanism of root cell differentiation and root system architecture in perennial woody species of Bambusoideae.

GenAI4Sustainability:GPT and Its Potentials For Achieving UN’s Sustainable Development Goals

SINCE 2015,17 Sustainable Development Goals(SDGs)have been understood as more promising blueprints for a peaceful,prosperous,and sustainable future[1]which are formulated to seek a framework to address global challenging issues such as poverty,inequality,and pollution.

Toward understanding the microstructure characteristics,phase selection and magnetic properties of laser additive manufactured Nd-Fe-B permanent magnets

Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infuenced by the phase characteristics and microstructure.In this work,Nd-Fe-B magnets were manufactured using vacuum induction melting(VIM),laser directed energy deposition(LDED)and laser powder bed fusion(LPBF)technologies.Themicrostructure evolution and phase selection of Nd-Fe-B magnets were then clarified in detail.The results indicated that the solidification velocity(V)and cooling rate(R)are key factors in the phase selection.In terms of the VIM-casting Nd-Fe-B magnet,a large volume fraction of theα-Fe soft magnetic phase(39.7 vol.%)and Nd2Fe17Bxmetastable phase(34.7 vol.%)areformed due to the low R(2.3×10-1?C s-1),whereas only a minor fraction of the Nd2Fe14B hard magnetic phase(5.15 vol.%)is presented.For the LDED-processed Nd-Fe-B deposit,although the Nd2Fe14B hard magnetic phase also had a low value(3.4 vol.%)as the values of V(<10-2m s-1)and R(5.06×103?C s-1)increased,part of theα-Fe soft magnetic phase(31.7vol.%)is suppressed,and a higher volume of Nd2Fe17Bxmetastable phases(47.5 vol.%)areformed.As a result,both the VIM-casting and LDED-processed Nd-Fe-B deposits exhibited poor magnetic properties.In contrast,employing the high values of V(>10-2m s-1)and R(1.45×106?C s-1)in the LPBF process resulted in the substantial formation of the Nd2Fe14B hard magnetic phase(55.8 vol.%)directly from the liquid,while theα-Fe soft magnetic phase and Nd2Fe17Bxmetastable phase precipitation are suppressed in the LPBF-processed Nd-Fe-B magnet.Additionally,crystallographic texture analysis reveals that the LPBF-processedNd-Fe-B magnets exhibit isotropic magnetic characteristics.Consequently,the LPBF-processed Nd-Fe-B deposit,exhibiting a coercivity of 656 k A m-1,remanence of 0.79 T and maximum energy product of 71.5 k J m-3,achieved an acceptable magnetic performance,comparable to other additive manufacturing processed Nd-Fe-B magnets from MQP(Nd-lean)Nd-Fe-Bpowder.

Exploring the Cation Regulation Mechanism for Interfacial Water Involved in the Hydrogen Evolution Reaction by In Situ Raman Spectroscopy

Interfacial water molecules are the most important participants in the hydrogen evolution reaction(HER).Hence,understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism.Unfortunately,investigating interfacial water is extremely challenging owing to the interference caused by bulk water molecules and complexity of the interfacial environment.Here,the behaviors of interfacial water in different cationic electrolytes on Pd surfaces were investigated by the electrochemistry,in situ core-shell nanostructure enhanced Raman spectroscopy and theoretical simulation techniques.Direct spectral evidence reveals a red shift in the frequency and a decrease in the intensity of interfacial water as the potential is shifted in the positively direction.When comparing the different cation electrolyte systems at a given potential,the frequency of the interfacial water peak increases in the specified order:Li+<Na^(+)<K^(+)<Ca^(2+)<Sr^(2+).The structure of interfacial water was optimized by adjusting the radius,valence,and concentration of cation to form the two-H down structure.This unique interfacial water structure will improve the charge transfer efficiency between the water and electrode further enhancing the HER performance.Therefore,local cation tuning strategies can be used to improve the HER performance by optimizing the interfacial water structure.

Improvement of synergistic effect photocatalytic/peroxymonosulfate activation for degradation of amoxicillin using carbon dots anchored on rod-like CoFe_(2)O_(4)

β-lactam antibiotics in aquatic environment have severely damaged ecological stability and caused a series of environmental pollution problems to be solved urgently.Herein,a novel composite photocatalyst prepared by loading carbon dots(CDs)onto rod-like CoFe_(2)O_(4)(CFO),which can effectively degrade amoxicillin(AMX)by photocata lytic/peroxy mono sulfate(PMS)activation under visible light irradiation.The degradation results exhibits that the optimal degradation efficiency with 97.5%within 80 min is achievd by the CDs-CFO-5 composite.Such enhanced activity is ascribed to the introduction of CDs that effectively improves the separation efficiency of photogenerated electron pairs and creates new active sites as electron bridges that improve the photocata lytic performance.More importantly,a strong synergistic between CDs and photo-induced electrons generated from CFO can further activiate PMS to provide more SO4-·and·OH radicals for boosting the degradation ability towards AMX.The present study aims to elucidate positive role of CDs in photocata lytic/peroxy monosulfate activation during the degradation reaction.

Effects of Jasmonic Acid on the Expression of Capsaicin Biosynthesis Related Genes in Chili Pepper(Capsicum annuum)

To explore the regulatory effects of jasmonic acid （JA） on the expression of the genes involved in capsaicin biosynthesis pathway, the mRNA expression of the genes was determined by fluorescence-based quantitative PCR 0, 4, 12, 24 and 48 h after chili peppers （Capsicum annuum var. conoides） were treated with 100 μmol/L JA, and the content of capsaicin was measured by high performance liquid chromatography （HPLC） 0, 1, 3, 6, 10 and 15 d after JA treatment. The results showed that JA upregulated the mRNA levels of pal, C4h, Comt, 4Cl, Hct, Paint, Bcat, FatA and pun1 in chili pepper, thus promoting the synthesis of capsaicin to different extents.

Cloning and Functional Characterization of Chalcone Isomerase Genes Involved in Anthocyanin Biosynthesis in Clivia miniata

Chalcone isomerase(CHI),catalyzing isomerization of chalcones,is a crucial enzyme in flavonoid biosynthesis.Three CHI genes were isolated from Clivia miniata and designated as CmCHI1,CmCHI2 and CmCHI3,respectively.Multiple sequence alignments and phylogenetic analysis showed that CmCHI1 and CmCHI2 were members of type I CHI proteins,whereas CmCHI3 belonged to type IV CHI proteins.Subcellular localization analysis found that all three CmCHIs had diffused distribution in the cytoplasm similar to green fluorescent protein(GFP).Anthocyanin biosynthesis and gene expression analysis demonstrated that CmCHIs were highly expressed in anthocyanin accumulated tissues.To further functionally characterize the role of CmCHIs,an in vitro enzymatic activity assay was carried out using the purified recombinant proteins.Results showed that CmCHI1 and CmCHI2 could completely convert the substrate naringenin chalcone(NC)into the product naringenin(NA),whereas CmCHI3 seemed nonfunctional as no increment of NA was detected.Further genetic transformation of Arabidopsis tt5-1 mutant validated that CmCHI1 and CmCHI2 rather than CmCHI3 could complement the chi deficient phenotypes.In summary,CmCHI1 and CmCHI2 are the real active CHI genes in Clivia miniata.The results not only broaden our knowledge on flavonoid biosynthesis in C.miniata but also lay a new foundation for further flavonoid modification in C.miniata.

Side-channel attack-resistant AES S-box with hidden subfield inversion and glitch-free masking

A side-channel attack(SCA)-resistant AES S-box implementation is proposed,which is an improvement from the power-aware hiding(PAH)S-box but with higher security and a smaller area.We use the composite field approach and apply the PAH method to the inversion in the nonlinear kernel and a masking method to the other parts.In addition,a delaymatched enable control technique is used to suppress glitches in the masked parts.The evaluation results show that its area is contracted to 63.3%of the full PAH S-box,and its power-delay product is much lower than that of the masking implementation.The leakage assessment using simulation power traces concludes that it has no detectable leakage under t-test and that it at least can thwart the moment-correlation analysis using 665000 noiseless traces.

Preventing Hardware Trojans in Switch Chip Based on Payload Decoupling

Hardware Trojans in integrated circuit chips have the characteristics of being covert,destructive,and difficult to protect,which have seriously endangered the security of the chips themselves and the information systems to which they belong.Existing solutions generally rely on passive detection techniques.In this paper,a hardware Trojans active defense mechanism is designed for network switching chips based on the principle of encryption algorithm.By encoding the data entering the chip,the argot hidden in the data cannot trigger the hardware Trojans that may exist in the chip,so that the chip can work normally even if it is implanted with a hardware Trojans.The proposed method is proved to be effective in preventing hardware Trojans with different trigger characteristics by simulation tests and practical tests on our secure switching chip.

Statics of FGM circular plate with magneto-electro-elastic coupling:axisymmetric solutions and their relations with those for corresponding rectangular beam

This paper investigates the static behavior of a functionally graded circular plate made of magneto-electro-elastic（MEE） materials under tension and bending.The analysis is directly based on the three-dimensional governing equations for magnetoelectro-elasticity, with the boundary conditions on the upper and lower surfaces satisfied exactly and those on the cylindrical surface satisfied approximately（in the Saint Venant sense）. The analytical solutions, derived with a direct displacement method, are valid for any functionally graded material（FGM） with its properties varying independently in a continuous manner along the thickness direction. For homogeneous materials, these solutions are degenerated to the ones available in the literature. Interesting relations are also found between the solutions for a functionally graded magneto-electro-elastic（FGMEE） circular plate and those for an FGMEE rectangular beam, and even those for a functionally graded elastic beam when only the elastic displacements are considered. The beam solutions are also derived using a direct displacement method. Numerical examples are presented to verify the present analytical solutions, show the effects of material heterogeneity and multi-field coupling, and indicate the correspondence between the plate solutions and beam solutions.

Smart palm-size optofluidic hematology analyzer for automated imaging-based leukocyte concentration detection

A critical function of flow cytometry is to count the concentration of blood cells,which helps in the diagnosis of certain diseases.However,the bulky nature of commercial flow cytometers makes such tests only available in hospitals or laboratories,hindering the spread of point-of-care testing(POCT),especially in underdeveloped areas.Here,we propose a smart Palm-size Optofluidic Hematology Analyzer based on a miniature fluorescence microscope and a microfluidic platform to lighten the device to improve its portability.This gadget has a dimension of 35×30×80 mm and a mass of 39 g,less than 5%of the weight of commercially available flow cytometers.Additionally,automatic leukocyte concentration detection has been realized through the integration of image processing and leukocyte counting algorithms.We compared the leukocyte concentration measurement between our approach and a hemocytometer using the Passing-Bablok analysis and achieved a correlation coefficient of 0.979.Through Bland-Altman analysis,we obtained the relationship between their differences and mean measurement values and established 95%limits of agreement,ranging from−0.93×10^(3)to 0.94×10^(3)cells/μL.We anticipate that this device can be used widely for monitoring and treating diseases such as HIV and tumors beyond hospitals.

Efflcient machining of a complex blisk channel using a disc cutter

For rough machining of a complex narrow cavity,e.g.,a complex blisk channel on an aero-engine,the typically used cutting tools are the slender cylindrical cutter and conical cutter.Nevertheless,as neither of the two is particularly suited for rough machining,wherein the main purpose is to remove a large volume as quickly as possible,the machining efficiency is low,especially when the part materials are of hard-to-cut types(e.g.,Titanium-alloy)for which it often takes days to rough machine a blisk.Fortunately,disc machining provides a new and efficient roughing solution,since a disc cutter with a large radius enables a much larger cutting speed and thus a larger material removal rate.However,due to the large radius of the disc cutter,its potential collision with narrow and twisted channels becomes a serious concern.In this paper,we propose a novel twophase approach for efficiently machining a complex narrow cavity workpiece using a disc-shaped cutter,i.e.,3+2-axis disc-slotting of the channel by multiple layers(rough machining)+five-axis disc-milling of the freeform channel side surfaces(semi-finish machining).Both simulation and physical cutting experiments are conducted to assess the effectiveness and advantages of the proposed method.The experimental results show that,with respect to a same cusp-height threshold on the channel side surfaces,the total machining time of the tested part by the proposed method is about only 36%of that by the conventional approach of plunging-milling(for roughing)plus milling by a slender cylindrical cutter(for semi-finishing).

3D inner-outer asymmetric sponge for enormous-volume emulsion wastewater treatment based on a new“demulsification-transport”mechanism

Although oily wastewater treatment realized by superwetting materials has attracted heightened attention in recent years,how to treat enormous-volume emulsion wastewater is still a tough problem,which is ascribed to the emulsion accumulation.Herein,to address this problem,a material is presented by subtly integrating chemical demulsification and 3D inner-outer asymmetric wettability to a sponge substrate,and thus wettability gradient-driven oil directional transport for achieving unprecedented enormous-volume emulsion wastewater treatment is realized based on a“demulsification-transport”mechanism.The maximum treatment volume realized by the sponge is as large as 3 L(2.08×10^(4) L per cubic meter of the sponge)in one cycle,which is about 100 times of the reported materials.Besides,owing to the large pore size of the sponge,9000 L m^(2)h^(-1)(LMH)separation flux and 99.5%separation efficiency are realized simultaneously,which overcomes the trade-off dilemma.Such a 3D inner-outer asymmetric sponge displaying unprecedented advantage in the treatment volume can promote the development of the oily wastewater treatment field,as well as expand the application prospects of superwetting materials,especially in continuous water treatment.

Accelerated corrosion of 316L stainless steel in a simulated oral environment via extracellular electron transfer and acid metabolites of subgingival microbiota

316L stainless steel(SS)is widely applied as microimplant anchorage(MIA)due to its excellent mechanical properties.However,the risk that the oral microorganisms can corrode 316L SS is fully neglected.Microbiologically influenced corrosion(MIC)of 316L SS is essential to the health and safety of all patients because the accelerated corrosion caused by the oral microbiota can trigger the release of Cr and Ni ions.This study investigated the corrosion behavior and mechanism of subgingival microbiota on 316L SS by 16S rRNA and metagenome sequencing,electrochemical measurements,and surface characterization techniques.Multispecies biofilms were formed by the oral subgingival microbiota in the simulated oral anaerobic environment on 316L SS surfaces,significantly accelerating the corrosion in the form of pitting.The microbiota samples collected from the subjects differed in biofilm compositions,corrosion behaviors,and mechanisms.The oral subgingival microbiota contributed to the accelerated corrosion of 316L SS via acidic metabolites and extracellular electron transfer.Our findings provide a new insight into the underlying mechanisms of oral microbial corrosion and guide the design of oral microbial corrosion-resistant materials.

GMAT:A Graph Modeling Method for Group Preference Prediction

Preference prediction is the building block of personalized services,and its implementation at the group level helps enterprises identify their target customers effectively.Existing methods for preference prediction mainly focus on behavioral interactions to extract the associations between groups and products,ignoring the importance of other auxiliary records(e.g.,online reviews and social tags)in association detection.This paper proposes a novel method named GMAT for group preference prediction,aiming to collectively detect the sophisticated association patterns from user generated content(UGC)and behavioral interactions.In doing so,we construct a tripartite graph to collaborate these two types of data,and design a deep-learning algorithm with mutual attention module for generating the contextualized representations of groups and products.Extensive experiments on two real-world datasets show that GMAT is superior to other baselines in terms of group preference prediction.Additionally,GMAT is able to improve prediction accuracy compared with its different variants,further verifying the proposed method’s effectiveness on association pattern detection.

Microglial glutaminase 1 mediates chronic restraint stress-induced depression-like behaviors and synaptic damages

Dear Editor,Major depressive disorder(MDD)is one of the most common psychiatric illnesses that significantly increase the risk of suicide.1 Stress-triggered dysfunctions of microglia have been identified as a commonly occurred pathological feature of MDD.1–3 Microglial dysfunction contributes to the pathogenesis of MDD via immunoresponses/neuroinflammation-mediated neural damage and pathological synapse loss-mediated neural circuit disruption.1 Although the involvement of microglia in MDD has been widely investigated,the molecular mechanisms underlying microglial dysfunction remain largely unknown.Recently,we identified glutaminase 1(Gls1)as one key protein that participates in microglial dysfunction.4–6 Gls1 catalyzes the hydrolysis of glutamine to produce glutamate in the brain.4 Besides its well-known role in excitatory neurotoxicity,we found Gls1 up-regulation in microglia in animal models of Alzheimer’s disease and ischemic stroke.4,7 Gls1 activates microglia to overproduce cytokines and release inflammatory extracellular vesicles,therefore leading to neuroinflammation in animal models of Alzheimer’s disease and ischemic stroke.4–6 More importantly,Gls1 has been found to be up-regulated in the brains of MDD patients,and microglial Gls1 deficiency mitigated LPS-induced depression-like behaviors.8 However,LPS exposure is not an appropriate model to mimic MDD phenotypes,leaving the involvement of Gls1 in MDD an undetermined question.

聚乙二醇含量对聚乳酸/聚丁二酸丁二醇酯合金结构与性能的影响

通过熔融共混制备了聚乳酸/聚丁二酸丁二醇酯/聚乙二醇(PLA/PBS/PEG)三相共混物,利用扫描电子显微镜、平板流变仪、差示扫描量热仪、动态力学热分析仪、万能拉力试验机和简支梁冲击试验机分别研究了PEG含量对PLA/PBS(80/20)合金微观结构与性能的影响。结果表明,添加PEG组分能够降低PBS分散相的尺寸、均化尺寸分布、增加界面层厚度;随着PEG含量增加,PLA/PBS/PEG共混物复数黏度降低并且剪切变稀行为更加显著,共混物中PLA组分的玻璃化转变温度和冷结晶温度降低幅度随着PEG含量增加而增大,同时结晶度增加。动态力学热分析曲线显示PLA与PBS组分的玻璃化转变温度相互靠近,说明PEG能够促进PLA与PBS的相容性。力学性能结果表明,添加PEG组分到PLA/PBS(80/20)共混物中,可以在拉伸强度降低幅度不大的情况下大幅度提高共混体系的韧性。

Effects of different nozzle materials on atomization results via CFD simulation

Spray drying,as a crucial operation in industrial production,converts solution to fine particle.The spray moiety directly affects the final particle morphology,size and distribution.Compared with the experimental method,computational fluid dynamics(CFD)modeling is a powerful and convenient tool for simulating the spray process.Based on the verified CFD model,different materials of atomizer were simulated to investigate the effect on droplet size and distribution in this work.The modeling result proved that the droplet size and distribution were influenced by the resistance coefficient of materials,wherein the Reynolds number could change the effect of roughness along with the change of mass flow rate on spray process.The results in this work have implication for controlling droplet size through developing new spray nozzle with different materials or surface coating.

Key technologies for medium and low voltage DC distribution system

Development of the medium and low voltage DC distribution system is of great significance to a regional transmission of electric energy,increasing a penetration rate of new energy,and enhancing a safety of the operation of the AC/DC interconnected grid.This paper first summarizes the medium and low voltage DC distribution system schemes and plans put forward by many countries,and then elaborate status of under-construction medium and low voltage DC distribution system project cases in China.Based on these project cases,this paper analyzes key issues involved in the medium and low voltage DC distribution system topologies,equipment,operation control technologies and DC fault protections,in order to provide theoretical and technical reference for future medium and low voltage DC distribution system-related projects.Finally,this paper combines a current China research status to summarize and give a prediction about the future research direction of medium and low voltage DC distribution system,which can provide reference for the research of medium and low voltage DC distribution system.