Uncertainty-Aware Physical Simulation of Neural Radiance Fields for Fluids

This paper presents a novel framework aimed at quantifying uncertainties associated with the 3D reconstruction of smoke from2Dimages.This approach reconstructs color and density fields from 2D images using Neural Radiance Field(NeRF)and improves image quality using frequency regularization.The NeRF model is obtained via joint training ofmultiple artificial neural networks,whereby the expectation and standard deviation of density fields and RGB values can be evaluated for each pixel.In addition,customized physics-informed neural network(PINN)with residual blocks and two-layer activation functions are utilized to input the density fields of the NeRF into Navier-Stokes equations and convection-diffusion equations to reconstruct the velocity field.The velocity uncertainties are also evaluated through ensemble learning.The effectiveness of the proposed algorithm is demonstrated through numerical examples.The presentmethod is an important step towards downstream tasks such as reliability analysis and robust optimization in engineering design.

Multi-Patch Black-White Topology Optimization in Isogeometric Analysis

Topological optimization plays a guiding role in the conceptual design process.This paper conducts research on structural topology optimization algorithm within the framework of isogeometric analysis.For multi-component structures,the Nitsche’smethod is used to glue differentmeshes to performisogeometricmulti-patch analysis.The discrete variable topology optimization algorithm based on integer programming is adopted in order to obtain clear boundaries for topology optimization.The sensitivity filtering method based on the Helmholtz equation is employed for averaging of curved elements’sensitivities.In addition,a simple averaging method along coupling interfaces is proposed in order to ensure the material distribution across coupling areas is reasonably smooth.Finally,the performance of the algorithm is demonstrated by numerical examples,and the effectiveness of the algorithm is verified by comparing it with the results obtained by single-patch and ABAQUS cases.

Greatly enhanced electro-optic modulation efficiency in titanium in-diffusion PIN-PMN-PT waveguide

Electro-optic modulators,which convert electrical signals onto the transmission light,are key devices in electro-optic modulating systems.Modulation efficiency is one of the most important parameters of an electro-optic modulator,which directly determines the footprint and power consumption of the device.Generally,modulation efficiency strongly depends on the electro-optic response of the crystal.The Pb(In_(1/2)Nb_(1/2))O_(3)-Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3)(PIN-PMN-PT)single crystal with giant electro-optic coefficient(λ_(c))and high transparency indicates the potential to achieve greatly enhanced modulation efficiency.In this study,a prototype PIN-PMN-PT phase modulator was fabricated based on a titanium(Ti)in-diffusion waveguide,which is reported for the first time.The influences of titanium in-diffusion on the composition and domain structure of the PIN-PMN-PT single crystal were studied by transmission electron microscopy(TEM)and piezoelectric force microscopy(PFM),respectively.Finally,a half-wave voltage(V_(π))of 2.3 V was obtained using a device with 6-mm-long(L)electrodes.Furthermore,the electro-optic modulation efficiency(V_(π)L)was calculated as 1.38 V-cm,which was approximately one order of magnitude lower than that of commercial lithium niobate(LiNbO_(3),LN)phase modulators.Such enhanced modulation efficiency indicates more compact device and lower power consumption,which is of great significance for electro-optic modulation systems used in micro-fiber gyroscope,integrated photonic devices,etc.

Boosting the piezoelectric property of relaxor ferroelectric single crystal via active manipulation of defect dipole polarization

To further enhance the property of piezoelectric materials is of great significance to improve the overall performance of electro-mechanical devices.Here in this work,we propose a thermal annealing and high temperature poling approach to achieve significantly enhanced piezoelectricity in Pb(In_(1/2)Nb_(1/2))O_(3)single bondPb(Mg_(1/3)Nb_(2/3))O_(3)single bondPbTiO_(3)(PIN-PMN-PT)crystals with a morphotropic phase boundary(MPB)composition.The main idea of our approach is to realize a more sufficiently polarized crystal via active manipulation of defects and orientation of defect polarization.Manipulation of defect dipoles by the high temperature poling is proved by the piezo-response force microscopy.Finally,a d_(33)of 3300 pC/N and a SE of 0.25%are obtained,nearly 60%higher than that of conventionally poled crystals.Moreover,such a boosting of piezoelectric property is obtained under a maintained Curie temperature.Our research not only reveals the active control of defect dipole via modified poling method in the PIN-PMN-PT crystal,but also provides a feasible strategy to further improve the property of piezoelectric materials.

Ferroelectric-to-relaxor transition and ultrahigh electrostrictive effect in Sm^(3+)-doped Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3)ferroelectrics ceramics

Rare-earth Sm^(3+)-doped Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.25PbTiO_(3)(PMN-0.25PT)ferroelectric ceramics with doping amounts between 0%-3%were developed via a conventional solid-state method.The doping effect of Sm^(3+)ions on the PMN-0.25PT matrix was systematically investigated on the basis of the phase structure,temperature-dependent dielectric,ferroelectric,and electrotechnical properties.Due to the disruption of long-range ferroelectric order,the addition of Sm^(3+)ions effectively lowers the Tm(temperature corresponding to maximum permittivity)of the samples,leading to enhanced relaxor ferroelectric(RFE)characteristic and superior electric field-induced strain(electrostrain)properties at room temperature.Intriguingly,a considerable large-signal equivalent piezoelectric coefficient d∗_(33)of 2376 pm/V and a very small hysteresis were attained in the PMN-0.25PT component doped with 2.5 mol.%Sm^(3+).The findings of piezoelectric force microscopy indicate that the addition of Sm^(3+)increases the local structural heterogeneity of the PMN-0.25PT matrix and that the enhanced electromechanical performance is due to the dynamic behavior of polar nanoregions.Importantly,strong temperature-dependent electrostrain and electrostrictive coefficient Q33 are observed in the critical region around Tm in all Sm^(3+)-modified PMN-0.25PT ceramic samples studied.This work elucidates the phase transition behavior of Sm^(3+)-doped PMN-0.25PT and reveals a critical region where electrostrictive properties can be greatly improved due to a strong temperature-dependent characteristic.

Metabolic Pathway of Monounsaturated Lipids Revealed by In-Depth Structural Lipidomics by Mass Spectrometry

The study of lipid metabolism relies on the characterization of the lipidome,which is quite complex due to the structure variations of the lipid species.New analytical tools have been developed recently for characterizing fine structures of lipids,with C=C location identification as one of the major improvements.In this study,we studied the lipid metabolism reprograming by analyzing glycerol phospholipid compositions in breast cancer cell lines with structural specification extended to the C=C location level.Inhibition of the lipid desaturase,stearoyl-CoA desaturase 1,increased the proportion of n-10 isomers that are produced via an alternative fatty acid desaturase 2 pathway.However,there were different variations of the ratio of n-9/n-7 isomers in C18:1-containing glycerol phospholipids after stearoyl-CoA desaturase 1 inhibition,showing increased tendency in MCF-7 cells,MDA-MB-468 cells,and BT-474 cells,but decreased tendency in MDA-MB-231 cells.No consistent change of the ratio of n-9/n-7 isomers was observed in SK-BR-3 cells.This type of heterogeneity in reprogrammed lipid metabolism can be rationalized by considering both lipid desaturation and fatty acid oxidation,highlighting the critical roles of comprehensive lipid analysis in both fundamental and biomedical applications.

Approaches to Nanoparticle Labeling:A Review of Fluorescent,Radiological,and Metallic Techniques

Nanomaterials are widely used in commercial products,resulting in the release of nanoscale particles into the environment.This raises concerns about their potential exposure risks in complex biological matrices.Most attempts use engineered nanomaterials(ENMs)to mimic the biological behavior of nanoparticles in the environment,and labeling of ENMs by sensors is a commonly used approach for sensitive detection and tracking of ENMs in organisms.However,due to the distinct physicochemical properties of nanoparticles,different labeling approaches have been developed,each with varying applicability.In this Review,we summarize the three main types of labeling methods used for nanoparticles:fluorescent,radiological,and metallic labeling.We discuss their labeling mechanisms,efficiency,stability,target nanoparticles,and applicability in different organism models.Finally,we propose a labeling scheme for specific nanoparticles.Overall,this Review provides a comprehensive overview of the advances in nanoparticle labeling techniques and their potential applications in environmental and health studies.

Mechanistic insights into sequestration of U(VI) toward magnetic biochar: Batch, XPS and EXAFS techniques

The magnetic iron oxide（Fe3O4） nanoparticles stabilized on the biochar were synthesized by fast pyrolysis of Fe（II）-loaded hydrophyte biomass under N2 conditions. The batch experiments showed that magnetic biochar presented a large removal capacity（54.35 mg/g）at pH 3.0 and 293 K. The reductive co-precipitation of U（VI） to U（IV） by magnetic biochar was demonstrated according to X-ray diffraction, X-ray photoelectron spectroscopy and X-ray absorption near edge structure analysis. According to extended X-ray absorption fine structure analysis, the occurrence of U-Fe and U-U shells indicated that high effective removal of uranium was primarily inner-sphere coordination and then reductive co-precipitation at low pH. These observations provided the further understanding of uranium removal by magnetic materials in environmental remediation.

Phase evolution and relaxor to ferroelectric phase transition boosting ultrahigh electrostrains in (1-x)(Bi_(1/2)Na_(1/2))TiO_(3)-x(Bi_(1/2)K_(1/2))TiO_(3) solid solutions

Owing to the complex composition architecture of these solid solutions,some fundamental issues of the classical(1-x)(Bi_(1/2)Na_(1/2))TiO_(3) -x(Bi_(1/2)K_(1/2))TiO_(3)(BNT-xBKT)binary system,such as details of phase evolution and optimal Na/K ratio associated with the highest strain responses,remain unresolved.In this work,we systematically investigated the phase evolution of the BNT-xBKT binary solid solution with x ranging from 0.12 to 0.24 using not only routine X-ray diffraction and weak-signal dielectric characterization,but also temperature-dependent polarization versus electric field(P-E)and current versus electric field(I-E)curves.Our results indicate an optimal Na/K ratio of 81/19 based on high-field polarization and elec-trostrain characterizations.As the temperature increased above 100?C,the x¼0.19 composition pro-duces ultrahigh electrostrains(>0.5%)with high thermal stability.The ultrahigh and stable electrostrains were primarily due to the combined effect of electric-field-induced relaxor-to-ferroelectric phase tran-sition and ferroelectric-to-relaxor diffuse phase transition during heating.More specifically,we revealed the relationship between phase evolution and electrostrain responses based on the characteristic tem-peratures determined by both weak-field dielectric and high-field ferroelectric/electromechanical property characterizations.This work not only clarifies the phase evolution in BNT-xBKT binary solid solution,but also paves the way for future strain enhancement through doping strategies.

Enhanced energy storage performance under low electric field in Sm^(3+) doped AgNbO_(3) ceramics

Herein,Ag_(1-3x)Sm_(x)NbO_(3)(0≤x≤0.025)antiferroelectric ceramics were successfully synthesized by solid state methods.The effect of Sm 3þdoping on the structure,property and energy storage performance were studied.With the increasing Sm^(3+)concentrations,the average grain size decreased.Meanwhile,the stability of high temperature M phases(i.e.,the structure between T_(f) and T_(3))was expanded,which led to low loss for energy storage.Both of structure analysis and ferroelectric tests revealed the existence of weakly polar/AFE-like phase below T_(f).The Sm 3þdoping tended to suppress the ferroelectric behavior and expand the stability of antiferroelectricity.Consequently,a significantly enhanced energy storage performance(W_(rec)=3.8 J/cm^(3),η=73%)could be achieved in Ag_(0.97)Sm_(0.01)NbO_(3) ceramic,which was almost 1.5 times larger than that in non-doped AgNbO_(3)(W_(rec)=2.4 J/cm^(3),η=45%)under the similar applied field of 1705 kV/cm±.In particular,the performance of the ceramic showed great temperature stability with variation of±5%from 25℃ to 125℃.These results indicated that the Ag_(0.97)Sm_(0.01)NbO_(3) ceramic could be an ideal lead-free candidate used in the energy storage field.

Enhanced antiferroelectric-like relaxor ferroelectric characteristic boosting energy storage performance of(Bi_(0.5)Na_(0.5))TiO_(3)-based ceramics via defect engineering

3Lead-free(BiasNaus)TiO_(3)(BNT)-based relaxor ferroelectric(RFE)ceramics have attracted a lot of atten-tion due to their high power density and rapid charge-discharge apabilities,as well as their potential application in pulse power capacitors.However,because of the desire for smaller electronic devices,their energy storage performance(ESP)should be enhanced even further.We describe a defect engineering strategy for enhancing the antiferroelectric-like RFE feature of BNT-based ceramics by unequal substi-tution of rare-earth La^(3+)in this paper.The ESP of La^(3+)-doped samples is raised by 25%with the same synthetic procedure and thidkness,due to an inrease in the critical electric field(E-field)and saturated E-field during polarization response,which is induced by a modifiation in the energy barrier between the lattice torsion.More impressively,an ultrahigh recoverable energy storage density Wrec of 8.58J/cm^(3)and a high energy storage efficiengyηof 945%are simultaneously attained in 3 at.%La^(3+)-substituted 0.6(Bi_(0.5)Na_(0.4)K_(0.1))_(1-1.5x)La_(x)TiO_(3)-0.4[2/3SrTiO_(3)-1/3Bi(Mg_(2/3)Ni_(1/3))O_(3)]RFE ceamics with good temperatue stability(W_(rec)=4.6±0.2 J/cm^(3)and higher n of 290%from 30℃to 120℃),frequency stability,and fatigue resistance.The significant inrease in ESP achieved through defect engineering not only proves the effectiveness of our strategy,but also presents a novel dielectric material with potential applications in pulse power apacitors.

Isogeometric analysis of multi-patch solid-shells in large deformation

In the context of isogeometric analysis(IGA)of shell structures,the popularity of the solid-shell elements benefit from formulation simplicity and full 3D stress state.However some basic questions remain unresolved when using solid-shell element,especially for large deformation cases with patch coupling,which is a common scene in real-life simulations.In this research,after introduction of the solid-shell nonlinear formulation and a fundamental 3D model construction method,we present a non-symmetric variant of the standardNitsche’s formulation for multi-patch coupling in associationwith an empirical formula for its stabilization parameter.An selective and reduced integration scheme is also presented to address the locking syndrome.In addition,the quasi-Newton iteration format is derived as solver,together with a step length control method.The second order derivatives are totally neglected by the adoption of the non-symmetric Nitsche’s formulation and the quasi-Newton solver.The solid-shell elements are numerically studied by a linear elastic plate example,then we demonstrate the performance of the proposed formulation in large deformation,in terms of result verification,iteration history and continuity of displacement across the coupling interface.

Abnormal phase transition and polarization mismatch phenomena in BaTiO_(3)-based relaxor ferroelectrics

Relaxor ferroelectrics have been extensively studied due to their outstanding dielectric,piezoelectric,energy storage,and electro-optical properties.Although various theories were proposed to elaborate on the relaxation phenomena,polar nanoregions formed by disruption of the long-range-order structures are considered to play a key role in relaxor ferroelectrics.Generally,relaxor ferro-electrics are formed by aliovalent substitution or isovalent substitution in normal ferroelectrics,or further combinations of solid solutions.Herein,one category of BaTiO_(3)-based relaxor ferroelectrics with abnormal phase transition and polarization mismatch phenomena is focused.Characteristic parameters of such BaTiO_(3)-based relaxor ferroelectrics,including the Curie temperature,polarization,and lattice parameter,show a typical“U”-shaped variation with compositions.The studied BaTiO_(3)-based relaxor ferroelectrics are mostly solid solutions of A-site coupling and B-site coupling ferroelectrics,exhibiting polarization mismatch in certain compositions[e.g.,0.9BaTiO_(3)-0.1BiScO_(3),0.8BaTiO_(3)-0.2Bi(Mg_(1/2)Ti_(1/2)O_(3),0.8BaTiO_(3)-0.2Bi(Mg_(2/3)Nb_(1/3)O_(3),0.5BaTiO_(3)-0.5Pb(Mg_(1/3)Nb_(2/3)O_(3),0.4BaTiO_(3)-0.6Pb(Zn_(1/3)Nb_(2/3)O_(30,etc.].Of particular interest is that excellent electrical properties can be achieved in the studied relaxor ferroelectrics.Therefore,polarization mismatch theory can also provide guidance for the design of new high-performance lead-free relaxor ferroelectrics.

Ultra-slim electrostrains with superior temperature-stability in leadfree sodium niobate-based ferroelectric perovskite

Large electrostrains with high temperature stability and low hysteresis are essential for applications in high-precision actuator devices.However,achieving simultaneously all three of the aforementioned features in ferroelectric ceramics remains a considerable challenge.In this work,we firstly report a high unipolar electrostrain(0.12%at 60 kV/cm)in(1ex)NaNbO_(3)-x[(Ba0.85Ca0.15)(Zr_(0.1)Ti_(0.9))O_(3)](NN-xBCZT)ferroelectric polycrystalline ceramics with excellent thermal stability(variation less than 10%in the temperature range of 30-160℃)and ultra-low hysteresis(<6%).Secondly,the high-field electrostrain response is dominated by the intrinsic electrostrictive effect,which may account for more than 80%of the electrostrain.Furthermore,due to the thermal stability of the polarization in the pure tetragonal phase,the large electrostrain demonstrates extraordinarily high stability from room temperature to 140℃.Finally,in-situ piezoelectric force microscopy reveals ultra-highly stable domain structures,which also guarantee the thermal stability of the electrostrain in(NN-xBCZT ferroelectrics ceramics.This study not only clarifies the origin of thermally stable electrostrain in NN-xBCZT ferroelectric perovskite in terms of electrostrictive effect,but also provides ideas for developing applicable ferroelectric ceramic materials used in actuator devices with excellent thermal stability.