Response of bedload transport, submarine topography, and dune internal structures to typhoon processes off Dongfang coast in the Beibu Gulf

Bedload sediment transport was estimated by the SEDTRANS96 model based on three-day hydrodynamics data obtained off the Dongfang coast in the Beibu Gulf during Typhoon Ketsana in September 2009. Bed- forms on the sea floor off the Dongfang coast and internal structures of a typical dune were interpreted to evaluate storm influences on individual dunes and the dune field. Results indicated that flow forcings and related bedload transport were both strengthened significantly due to Typhoon Ketsana. The measurements and modeling results, which mainly included three different stages, presented noticeable phasic variation. The three stages were dominated by tidal current （Period I）, tidal current combined with wind-induced waves （Period II）, and swells combined with tidal current and seaward flows （Period III）. This phasic varia- tion could be a common trait of hydrodynamics due to typhoons moving westwardly to the south of Hainan Island and Beibu Gulf in South China Sea. Results indicated that the maximum bedioad transport rate for every burst in Period III was almost 100 times larger than that in Period I and was ten times larger than that in Period II. However, the short-term increase in bedload transport induced by storms like Ketsana did not change the long-term evolution of dune morphology. Evidence was given by the internal structures of a typical dune, which revealed renewed modification under subsequent moderate conditions after storm ero- sion. Instead, storms may influence at different scales and regional allocation of sand dunes in some large areas because changes of the sea floor in large scales can hardly be recovered. More surveys during and after storm passage are also needed to document the level of positive contribution to forward migration.

Advances in polishing of internal structures on parts made by laser-based powder bed fusion

The internal structures of metallic products are important in realizing functional applications.Considering the manufacturing of inner structures,laser-based powder bed fusion(L-PBF)is an attractive approach because its layering principle enables the fabrication of parts with customized interior structures.However,the inferior surface quality of L-PBF components hinders its productization progress seriously.In this article,process,basic forms,and applications relevant to L-PBF internal structures are reviewed comprehensively.The causes of poor surface quality and differences in the microstructure and property of the surface features of L-PBF inner structures are presented to provide a perspective of their surface characteristics.Various polishing technologies for L-PBF components with inner structures are presented,whereas their strengths and weaknesses are summarized along with a discussion on the challenges and prospects for improving the interior surface quality of L-PBF parts.

Effect of internal structure of a batch-processing wet-etch reactor on fluid flow and heat transfer

Batch-processing wet-etch reactors are the key equipment widely used in chip fabrication,and their performance is largely affected by the internal structure.This work develops a three-dimensional computational fluid dynamics(CFD)model considering heat generation of wet-etching reactions to investigate the fluid flow and heat transfer in the wet-etch reactor.The backflow is observed below and above the wafer region,as the flow resistance in this region is high.The temperature on the upper part of a wafer is higher due to the accumulation of reaction heat,and the average temperature of the side wafer is highest as its convective heat transfer is weakest.Narrowing the gap between wafer and reactor wall can force the etchant to flow in the wafer region and then facilitate the convective heat transfer,leading to better within-wafer and wafer-to-wafer etch uniformities.An inlet angle of 60°balances fluid by-pass and mechanical energy loss,and it yields the best temperature and etch uniformities.The batch with 25wafers has much wider flow channels and much lower flow resistance compared with that with 50wafers,and thus it shows better temperature and etch uniformities.These results and the CFD model should serve to guide the optimal design of batch-processing wet-etch reactors.

The Multi-Objective Optimization of AFPM Generators with Double-Sided Internal Stator Structures for Vertical Axis Wind Turbines

The axial flux permanent magnet(AFPM)generator with double-sided internal stator structure is highly suitable for vertical axis wind turbines due to its high power density.The performance of the AFPM generator with double-sided internal stator structure can be improved by the reasonable design of electromagnetic parameters.To further improve the overall performance of the AFPM generator with double-sided internal stator structure,multivariable(coil widthω_(c),permanent magnet thickness h,pole arc coefficient α_(p) and working air gap l_(g))and multi-objective(generator efficiencyη,total harmonic distortion of the voltage THD and induced electromotive force amplitude EMF)functional relationships are innovatively established.Orthogonal analysis,mean analysis and variance analysis are performed on the influence parameters by combining the Taguchi method and response surface methodology to study the influence degrees of each influence parameter on the optimization objectives to determine the most appropriate electromagnetic parameters.The optimization results are verified by 3D finite element analysis.The optimized APFM generator with double-sided internal stator structure exhibits superior economy,stronger magnetic density,higher efficiency and improved power quality.

Earth: Review Article

Every year on 22 April, we have celebrated Earth Day and the beautiful planet we call home. Earth Day, established in 1970, has been used to highlight our planet’s environmental challenges and raise awareness of the importance of protecting our world for future generations [1]. To provide the protection of our planet, we should explain Earth’s environmental challenges to the best of our knowledge in frames of contemporary Geophysics. This paper gives a short overview of the developed Hypersphere World-Universe Model (WUM) and pay particular attention to the principal role of Dark Matter (DM) in the Earth’s life. In this manuscript, we discuss different aspects of the Earth: a condition of Young Earth before the Beginning of life on It;Internal Structure;“The 660-km Boundary” that we named Geomagma;Random Variations of Earth’s Rotational Speed on a daily basis;Origin of Moon;Expanding Earth;Internal Heating;Faint Young Sun paradox;Geocorona and Planetary Coronas;High-Energy Atmospheric Physics. WUM proposed principally different ways to solve the problems of Internal Heating, Origin of the Moon, and Faint Young Sun paradox based on DM core of the Earth. The Model revealed the fact that the Sun Activity causes the Geomagma Activity and, as a consequence, Random Variations of Earth’s Rotational Speed by the varying Sun’s magnetic field.

Temporal variations in internal tide multimodal structure on the continental shelf, South China Sea

Temporal variations in multimodal structures of diurnal( D_1) and semidiurnal( D_2) internal tides were investigated on the continental slope of the Dongsha Plateau, based on 2-month moored acoustic Doppler current profiler observations. Harmonic analysis indicated that the D_1 components( K_1 and O_1) dominated the internal tide field. The vertical structure of the K_1 constituent presented a first-mode structure while the M_2 constituent seemed to exhibit a high-mode structure. Amplitude spectra analysis of the current data revealed differences in baroclinic current amplitudes between different water depths. Temporal variations in modal structures ware analyzed, based on the D_1 and D_2 baroclinic tides extracted from the baroclinic velocity field with band-pass filters. Analysis showed that the magnitude of the D_1 internal tide current was much larger than the D_2 current, and temporal variations in the modal structure of the D_1 internal tide occurred on an approximately fortnightly cycle. The EOF analyses revealed temporal transformation of multimodal structures for D_1 and D_2 internal tides. The enhancement of the D_1 internal tide was mainly due to the superposition of K_1 and O_1, according to the temporal variation of coherent kinetic energy.

The effect of internal tides on the vertical structure of tidal current in the North Huanghai Sea

The tidal current is generally predominant in China's offshore areas. The vertical structure of the observedtidal current is quite complicated with the presence of seasonal thermocline. The observed tidal current may be divided into two parts, an averaged barotropic tide current and a variation tide current. A method for studying the vertical structure of tidal current is developed from the constitution and distribution of energy, and the vertical structure of the observed tide current in the North Huanghai Sea is studied on the basis of the method. The result shows that the reason why the energy of the tidal current is concentrated on the neighbourhood of the thermocline mainly lies in the internal tides i under certain conditions, the fact that the direction of the internal tide current above the thermocline is opposite to the one below the thermocline will be able to cause the rotary directions of the observed tidal current above and below the thermocline to be in opposite. The interaction between the averaged barotropic and the variation tide current plays an important role in forming the vertical structure of the tidal current, and it is mainly the interaction that results in the inho-mogeneous distribution of the tide current energy in the entire water column ; the ratio between the total energies of the internal tide current above the thermocline and the variation tide current in the entire water column is greater than the ratio between the total energies of that below the thermocline and the variation's. In a strong internal tide area such as the neighbourhood of Station L4, at diurnal tide frequency, the above-mentioned corresponding ratios are about 38. 82% and 29. 88%, respectively, and the energy of the internal tide current is about 68. 70%of the energy of the variation tide current; at semidiurnal tide frequency, the above-mentioned corresponding ratios are about 26. 61 % and 19. 73% , respectively, and the total internal tide current energy is about 46. 36% of the total variation tide current energy.

AN ANALYTICAL METHOD FOR SOLVING INTERNAL FORCES AND DEFORMATIONS OF BAR-SYSTEM STRUCTURE IN SPACE

In this paper, based on the idea of finite element method, the initial parametric method in bending, problem of a beam is extended to analyse the bar-system structure by employing Dirac function and llcavisidc step function.Then a new method for analysing the internal forces and deformations of bar-system structure in space is suggested by improving the mixed method in statically indeterminate structure.The inferred process and obtained answer will be more succinct and accurate when the problem of internal forces and deformations of bar-system structure is analysed by using the new method provided in this paper.

Effects of Internal Relaxation under Inplane Strain on the Structural,Electronic and Optical Properties of Perovskite BaZrO3

We present the specific ab-initio calculations that detail the variations of perovskite BaZrO3 caused by in-plane strain. Specifically, the internal relaxation, which was not captured in the widely used biaxial strain model, was included in a complementary manner to lattice relaxation. Density functional theory as well as a hybrid functional method based on a plane wave basis set was employed to calculate the lattice structure, elastic constants, electronic properties and optical properties of perovskite BaZrO3. The lattice parameter c exhibited a clear linear dependence on the imposed in-plane strain, but the Poisson＇s ratio caused by internal relaxation was smaller than the elastic deformation, indicating an ＂inelastic＂ or ＂plastic＂ relaxation manner caused by the introduction of internal relaxation. As a result, the related electronic and optical properties of perovskite BaZrO3 were also strongly affected by the in-plane strain, which revealed an effective way to adjust the properties of perovskite BaZrO3 via internal relaxation.

Construction of Oriented Structure in Inner Surface of Small-Diameter Artificial Blood Vessels:A Review

There is an urgent need for small-diameter artificial blood vessels in clinic.Physical,chemical and biological factors should be integrated to avoid thrombosis and intimal hyperplasia after implantation and to promote successful fabrication of small-diameter artificial blood vessels.From a physical perspective,the internal oriented structures of natural blood vessels plays an important role in guiding the directional growth of cells,improving the blood flow environment,and promoting the regeneration of vascular tissue.In this review,the effects of the oriented structures on cells,including endothelial cells(ECs),smooth muscle cells(SMCs)and stem cells,as well as the effect of the oriented structures on hemodynamics and vascular tissue remodeling and regeneration are introduced.Various forms of oriented structures(fibers,grooves,channels,etc.)and their construction methods are also reviewed.Conclusions and future perspectives are given.It is expected to give some references to relevant researches.

The coordinated impact of forest internal structural complexity and tree species diversity on forest productivity across forest biomes

Forest structural complexity can mediate the light and water distribution within forest canopies,and has a direct impact on forest biodiversity and carbon storage capability.It is believed that increases in forest structural complexity can enhance tree species diversity and forest productivity,but inconsistent relationships among them have been reported.Here,we quantified forest structural complexity in three aspects(i.e.,horizontal,vertical,and internal structural complexity)from unmanned aerial vehicle light detection and ranging data,and investigated their correlations with tree species diversity and forest productivity by incorporating field measurements in three forest biomes with large latitude gradients in China.Our results show that internal structural complexity had a stronger correlation(correlation coefficient=0.85)with tree species richness than horizontal structural complexity(correlation coefficient=-0.16)and vertical structural complexity(correlation coefficient=0.61),and it was the only forest structural complexity attribute having significant correlations with both tree species richness and tree species evenness.A strong scale effect was observed in the correlations among forest structural complexity,tree species diversity,and forest productivity.Moreover,forest internal structural complexity had a tight positive coordinated contribution with tree species diversity to forest productivity through structure equation model analysis,while horizontal and vertical structural complexity attributes have insignificant or weaker coordinated effects than internal structural complexity,which indicated that the neglect of forest internal structural complexity might partially lead to the current inconsistent observations among forest structural complexity,tree species diversity,and forest productivity.The results of this study can provide a new angle to understand the observed inconsistent correlations among forest structural complexity,tree species diversity,and forest productivity.

Protection of Innovative Achievements,Spatial Spillover,and Internal Structural Upgrading of the Productive Service Industry-Empirical Evidence from 28 Provinces in China

This study measured the level of innovation achievement protection and the degree of internal structural upgrading of the productive service industry in 28 provinces of China from 2000 to 2022.Exploratory spatial analysis methods were used to test the spatial correlation between the two variables,and the spatial impact of innovation achievement protection on the optimization of the internal structure of the productive service industry was examined at the national and sectoral levels.The results showed three main aspects of this system.(1)The agglomeration level of innovation achievement protection and internal structure optimization of the productive service industry between regions in China continued to increase during the sample period,and there was a clear similarity and synchronicity in the spatial evolution of the two variables.(2)The overall improvement in the protection level of innovative achievements is conducive to promoting the internal structural upgrading of China’s productive service industry.However,there are significant differences in the degree to which the protection of innovative achievements affects the internal structural upgrading of the productive service industry in the four major regions of the East,Central,Northeast,and West.The protection of innovative achievements in the East and Central regions significantly promotes the internal structural optimization of the productive service industry,while this effect is not significant in the western and northeastern regions.(3)The results of the robustness test indicate that the impact of internal structural upgrading of the productive service industry in the previous year on the level of innovation achievement protection is not significant.The interference from abnormal values of the internal structural upgrading of the productive service industry in various regions and the influence of municipalities directly under the central government on the regression results are not significant.After replacing the main variable,the coefficient of the innovation achievement protection level remained significantly positive.The conclusions of this study supplement and improve the theory of innovation achievement protection and industrial transformation and upgrading,providing decision-making support for improving the level of innovation achievement protection and promoting the internal structural upgrading of the productive service industries in China.

A Review of Current Research and Advances in Unmanned Surface Vehicles

Following developments in artificial intelligence and big data technology,the level of intelligence in intelligent vessels has been improved.Intelligent vessels are being developed into unmanned surface vehicles(USVs),which have widely interested scholars in the shipping industry due to their safety,high efficiency,and energy-saving qualities.Considering the current development of USVs,the types of USVs and applications domestically and internationally are being investigated.USVs emerged with technological developments and their characteristics show some differences from traditional vessels,which brings some problems and advantages for their application.Certain maritime regulations are not applicable to USVs and must be changed.The key technologies in the current development of USVs are being investigated.While the level of intelligence is improving,the protection of cargo cannot be neglected.An innovative approach to the internal structure of USVs is proposed,where the inner hull can automatically recover its original state in case of outer hull tilting.Finally,we summarize the development status of USVs,which are an inevitable direction of development in the marine field.

Theoretical calculation of tidal Love numbers of the Moon with a new spectral element method

The tidal Love numbers of the Moon are a set of nondimensional parameters that describe the deformation responses of the Moon to the tidal forces of external celestial bodies.They play an important role in the theoretical calculation of the Moon’s tidal deformation and the inversion of its internal structure.In this study,we introduce the basic theory for the theoretical calculation of the tidal Love numbers and propose a new method of solving the tidal Love numbers:the spectral element method.Moreover,we explain the mathematical theory and advantages of this method.On the basis of this new method,using 10 published lunar internal structure reference models,the lunar surface and lunar internal tidal Love numbers were calculated,and the influence of different lunar models on the calculated Love numbers was analyzed.Results of the calculation showed that the difference in the second-degree lunar surface Love numbers among different lunar models was within 8.5%,the influence on the maximum vertical displacement on the lunar surface could reach±8.5 mm,and the influence on the maximum gravity change could reach±6μGal.Regarding the influence on the Love numbers inside the Moon,different lunar models had a greater impact on the Love numbers h_(2) and l_(2) than on k_(2) in the lower lunar mantle and core.

Influence of reference states on Jupiter’s dynamo simulations

Jupiter’s magnetic field is thought to be generated in its deep metallic hydrogen region through dynamo action,yet the detailed dynamic process remains poorly understood.Numerical simulations have produced Jupiter-like magnetic fields,albeit using different control parameters and reference state models.In this study,we investigate the influence of different reference state models,based on ab initio calculations and based on the polytropic equation of state.In doing so,we perform five anelastic convection dynamo simulations that can be divided into two groups.In each group,different reference states are used while other control parameters and conditions are set to be identical.We find the reference state model can be very influential for the simulations in which buoyancy force is dominant over the Lorentz force.In this regime,different dynamical outcomes can be attributed to the effective buoyancy force resulting from different reference states.For simulations in which the Lorentz force is dominant over the buoyancy force,however,dynamo actions tend to be insensitive to different reference state models.If Jupiter’s dynamo is in a strong field regime,i.e.,the Lorentz force plays a dominant role,our numerical results suggest that Jupiter’s internal reference state,which remains poorly constrained,may play a minor role in the dynamo process of the planet.

Efficient electrocatalytic CO_(2)reduction to C_(2+)chemicals on internal porous copper

To improve the electrocatalytic conversion of carbon dioxide(CO_(2))into C_(2+)products(such as ethylene(C_(2)H_(4))and ethanol(CH_(3)CH_(2)OH),etc.)is of great importance,but remains challenging.Herein,we proposed a strategy that directs the C–C coupling pathway through enriching and confining the carbon monoxide(CO)intermediate to internal pores of Cu nanocubes,for electrocatalytic reduction of CO_(2)into C_(2+)chemicals.In H-type cell,the Faraday efficiency(FE)for ethylene and ethanol reaches 70.3%at−1.28 V versus the reversible hydrogen electrode(vs.RHE),with a current density of 47.9 mA·cm^(−2).In flow cell,the total current density is up to 340.3 mA·cm^(−2)at^(−2).38 V(vs.RHE)and the FE for C_(2+)products is 67.4%.Experimental and theoretical studies reveal that both the CO intermediate adsorption and C–C coupling reaction on such an internal porous catalyst are facilitated,thus improving CO_(2)-to-C_(2+)conversion efficiency.

Research on transformation and upgrading of traditional manufacturing industry under the background of reducing capacity

In today＇s economic situation, overcapacity of Chinese traditional manufacturing industry poses a serious threat to sustaineck rapid and healthy development of economy. The primary reasons of excess capacity of Chinese traditional manufacturing industry are the discordant between consumption and investment, the irrational industrial structure, export is not ideal and other causes. Overcapacity of traditional manufacturing industry will lead to business failures, unemployment citizen, deflation, financial risk and other series consequences. We should learn from foreign experience in the processing of excess capacity of traditional manufacturing industry and deal with excess capacity of traditional manufacturing industry in different aspects, so as to ensure stable and healthy development of our country＇ s economy.

Shapes,structures,and evolution of small bodies

Small bodies are among the best tracers of our Solar System’s history.A large number of space missions to small bodies(past and future)offer a unique opportunity to use these bodies as a natural laboratory to study the different processes,mechanical structures,and responses that drive the origin and evolution of small bodies,which are connected to the origin,evolution,and current architecture of the Solar System.Images of small bodies sent by spacecraft have revealed unexpectedly rich and complex geological worlds.In addition to very diverse compositions,small bodies in the Solar System have highly diverse shapes and structures,which reflect both different evolutionary paths and material properties.Furthermore,each individual body has diverse geological features on its surface,which include craters of various sizes and depths,boulders of different sizes and morphologies,lineaments,fractures,pits,signatures of landslides,terraces,and ridges.Such a geological richness could not be detected via ground-based observations,and we are still at the beginning of understanding their significance on the low-gravity surfaces on which they manifest.The combination of space mission data and numerical modeling allows us to enrich our understanding of the origin,evolution,and physical properties of these fascinating bodies.For instance,starting from the shape models,bulk densities,and spin rates determined from space mission data,we can investigate the formation mechanisms that lead to the observed properties of small bodies.We can also infer the interior and mechanical properties(e.g.,friction and cohesion)that allow a small body to be structurally stable,as well as its further potential evolution under processes such as a spin rate increase or an impact.Then,considering the various processes that these bodies experience during their evolution,we can investigate how these processes modify their properties and,in turn,how those properties influence the outcome of these processes.This paper reviews our current knowledge of small-body shapes and structures and discusses the various processes that are responsible for their formation and evolution,which can modify the characteristics of the bodies.We separately consider each population of small bodies,although in some cases,such as active asteroids and comets,the distinction between two populations solely in terms of physical properties is not clear.We then summarize the main findings regarding the physical properties of small bodies that have been the target of rendezvous or sample return missions.

Understanding the Moon's internal structure through moonquake observations and remote sensing technologies

Explorations for the interior structure of the Moon mainly involve three technologies: the early gravitational observations via circumlunar satellites, the moonquake observations during the Apollo period, and the recent high-resolution remote sensing observations. Based on these technologies, we divided the development of the moon's interior structure into three stages. The first stage is the discovery of high-density anomalous masses(mascons) on the lunar surface with the low-order gravitational field models, which were obtained by observing perturbations of the early lunar orbital satellites. The second stage is the preliminary understanding of the layer structure with the help of moonquake observations during the Apollo period. The third stage is the deep understanding of the structure of the lunar crust, mantle, and core, with the use of high-resolution remote sensing data and the reassessment of moonquake data from the Apollo's mission. This paper gave detailed introduction and comments on different observation technologies, gathered data, and data processing techniques used at the three stages. In addition, this paper analyzed the current issues in the researches on the Moon's internal structure and discussed the prospects for future explorations.

Gauge invariance and quantization applied to atom and nucleon internal structure

The prevailing theoretical quark and gluon momentum,orbital angular momentum and spin operators,satisfy either gauge invariance or the corresponding canonical commutation relation,but one never has these operators which satisfy both except the quark spin.The conflicts between gauge invariance and the canonical quantization requirement of these operators are discussed.A new set of quark and gluon momentum,orbital angular momentum and spin operators,which satisfy both gauge invariance and canonical momentum and angular momentum commutation relation,are proposed.To achieve such a proper decomposition the key point is to separate the gauge field into the pure gauge and the gauge covariant parts.The same conflicts also exist in QED and quantum mechanics,and have been solved in the same manner.The impacts of this new decomposition to the nucleon internal structure are discussed.