Construction of MnS/MoS_(2) heterostructure on two-dimensional MoS_(2) surface to regulate the reaction pathways for high-performance Li-O_(2) batteries

The inherent catalytic anisotropy of two-dimensional(2D) materials has limited the enhancement of LiO_(2) batteries(LOBs) performance due to the significantly different adsorption energies on 2D and edge surfaces.Tuning the adsorption strength in 2D materials to the reaction intermediates is essential for achieving high-performance LOBs.Herein,a MnS/MoS_(2) heterostructure is designed as a cathode catalyst by adjusting the adsorption behavior at the surface.Different from the toroidal-like discharge products on the MoS_(2) cathode,the MnS/MoS_(2) surface displays an improved adsorption energy to reaction species,thereby promoting the growth of the film-like discharge products.MnS can disturb the layer growth of MoS_(2),in which the stack edge plane features a strong interaction with the intermediates and limits the growth of the discharge products.Experimental and theoretical results confirm that the MnS/MoS_(2) heterostructure possesses improved electron transfer kinetics at the interface and plays an important role in the adsorption process for reaction species,which finally affects the morphology of Li_2O_(2),In consequence,the MnS/MoS_(2) heterostructure exhibits a high specific capacity of 11696.0 mA h g^(-1) and good cycle stability over 1800 h with a fixed specific capacity of 600 mA h g^(-1) at current density of100 mA g^(-1) This work provides a novel interfacial engineering strategy to enhance the performance of LOBs by tuning the adsorption properties of 2D materials.

Tailoring two-dimensional surfaces with pillararenes based host-guest chemistry

The two-dimensional surfaces have been fueled by the infinite possibility they offe red fo r basic re search,and for novel technologies in nanoelectronics.To realize many of these promises,the effective strategies were to design and control their surface chemistry,which plays a vital role in determining the chemical and physical properties.Macrocyclic host-guest chemistry with the reversible noncovalent interactions between macrocyclic hosts and suitable guests can be readily used for constructing multifunctional surfaces.Macrocyclic pillararenes,possessed the unique structure,have attracted the attentions of researchers in recent years.This feature article covers the recent development of pillararene-based twodimensional inte rfaces,including the fabrication and function of the hybrid composite.The combination of pillararenes and materials platform exhibited the novel property because of the characte ristic of cavity of macrocyclic host and confined spaces of surfaces.We anticipate that this review will be helpful to the researchers working in the fields of supramolecular chemistry and materials science.

Finite difference time domain analysis of two-dimensional surface acoustic wave piezoelectric phononic crystals at radio frequency

The finite-difference time-domain （FDTD） method is proposed for analyzing the surface acoustic wave （SAW） propagation in two-dimensional （2D） piezoelectric phononic crystals （PCs） at radio frequency （RF）, and also experiments are established to demonstrate its analysis result of the PCs＇ band gaps. The FDTD method takes the piezoelectric effect of PCs into account, in which periodic boundary conditions are used to decrease memory/time consumption and the perfectly matched layer boundary conditions are adopted as the SAW absorbers to attenuate artificial reflections. Two SAW delay lines are established with/without piezoelectric PCs located between interdigital transducers. By removing several echoes with window gating function in time domain, delay lines transmission function is achieved. The PCs＇ transmission functions and band gaps are obtained by comparing them in these two delay lines. When Aluminum/128°YX-LiNbO3 is adopted as scatter and substrate material, the PCs＇ band gap is calculated by this FDTD method and COMSOL respectively. Results show that computational results of FDTD agree well with experimental results and are better than that of COMSOL.

基于Surface Evolver模拟的两平行板间液桥剪切力学特性研究

液桥剪切行为广泛存在于粗糙界面接触、颗粒聚并与合成、微芯片自组装等与力学、化工、环境以及生物相关领域中,对相关系统和装备的服役性能有重要影响.本文采用Surface Evolver软件模拟研究了剪切作用下两平行板间受限液桥的液面轮廓和固液界面力的演变,基于最小能量原则建立了双圆台理论模型,并将二者进行了比较.结果表明:随着液桥剪切位移的增大,接触角滞后和切向力也线性递增,而法向力则以二次函数的形式单调递减;当增大液体体积或减小两平板垂直间距时,液桥切向力在接触角滞后和颈部半径的综合作用下出现递增趋势,而法向力的演变规律取决于液面内外压差和表面张力垂直分量的相对大小,这导致其随两平板间距的增大出现先递增后减小的变化;双圆台理论模型很好地拟合了液桥力的变化趋势,但模型对真实液面轮廓进行了简化处理,导致理论值与模拟值间存在一定的差距,这个差距可以通过一个无量纲形状系数来弥补,模型越精准,形状系数越接近于1.

Research status and prospects of the fractal analysis of metal material surfaces and interfaces

As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties.Fractal analysis has been used to characterize the shapes of metal materials at various scales and dimensions.Conventional methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and interfaces.However,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal materials.From the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear surfaces.The relationship between the fractal dimensions and properties of metal material surfaces and interfaces is summarized.Starting from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be developed.It is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.

3D Printing of Tough Hydrogel Scaffolds with Functional Surface Structures for Tissue Regeneration

Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.

Influence of surface layer slurry temperature on surface cracks and holes of ZTC4 titanium alloy by investment casting

In this work,the influences of surface layer slurry at different temperatures(10℃,14℃,18℃,22℃)on wax patterns deformation,shrinkage,slurry coating characteristics,and the surface quality of the casting were investigated by using a single factor variable method.The surface morphologies of the shell molds produced by different temperatures of the surface(first)layer slurries were observed via electron microscopy.Furthermore,the microscopic composition of these shell molds was obtained by EDS,and the osmotic effect of the slurry on the wax patterns at different temperatures was also assessed by the PZ-200 Contact Angle detector.The forming reasons for the surface cracks and holes of thick and large ZTC4 titanium alloy by investment casting were analyzed.The experimental results show that the surface of the shell molds prepared by the surface layer slurry with a low temperature exhibits noticeable damage,which is mainly due to the poor coating performance and the serious expansion and contraction of wax pattern at low temperatures.The second layer shell material(SiO_(2),Al_(2)O_(3))immerses into the crack area of the surface layer,contacts and reacts with the molten titanium to form surface cracks and holes in the castings.With the increase of the temperature of surface layer slurry,the damage to the shell surface tends to weaken,and the composition of the shell molds'surface becomes more uniform with less impurities.The results show that the surface layer slurry at 22℃is evenly coated on the surface of the wax patterns with appropriate thickness,and there is no surface shell mold rupture caused by sliding slurry after sand leaching.The surface layer slurry temperature is consistent with the wax pattern temperature and the workshop temperature,so there is no damage of the surface layer shell caused by expansion and contraction.Therefore,the shell mold prepared by the surface layer slurry at this temperature has good integrity,isolating the contact between the low inert shell material and the titanium liquid effectively,and the ZTC4 titanium alloy cylinder casting prepared by this shell mold is smooth,without cracks and holes.

Giant enhancement of negative friction by resonant coupling between localized surface phonon polaritons and graphene plasmonics

Negative friction refers to a frictional force that acts in the same direction as the motion of an object, which has been predicted in terahertz(THz) gain systems [Phys. Rev. B 108 045406(2023)]. In this work, we investigate the enhancement of the negative friction experienced by nanospheres placed near a graphene substrate. We find that the magnitude of negative friction is related to the resonant coupling between the surface plasmon polaritons(SPPs) of the graphene and localized surface phonon polaritons(LSPh P) of nanospheres. We exam nanospheres consisted of several different materials, including SiO_(2), Si C, Zn Se, Na Cl, ln Sb. Our results suggest that the LSPh P of Na Cl nanospheres match effectively with the amplified SPPs of graphene sheets. The negative friction for Na Cl nanospheres can be enhanced about one-to-two orders of magnitude compared to that of silica(SiO_(2)) nanospheres. At the resonant peak of negative friction, the required quasi-Fermi energy of graphene is lower for Na Cl nanospheres. Our finds hold great prospects for the mechanical manipulations of nanoscale particles.

Microstructure evolution of 7050 aluminum forgings during surface cumulative plastic deformation

To elucidate the mechanisms of regulating the microstructure uniformity in 7050 aluminum forgings through surface cumulative plastic deformation(SCPD),the microstructure under different solution treatments was investigated using metallographic observation(OM),electron backscatter diffraction(EBSD),transmission electron microscopy(TEM),and X-ray diffraction(XRD).The findings demonstrate that the most uniform microstructure in the forgings is achieved with a solution treatment at 470℃for 30 min.The SCPD process generates a significant number of needle-shaped precipitates,resulting in a higher dislocation density and stored energy.Solution treatments alleviate the pinning effect of second-phase particles and facilitate static recrystallization(SRX)in forgings,leading to a reduction in grain size.Additionally,mechanical testing results demonstrate 7%−13%increase in tensile strength and more uniform elongation of the forgings in different directions.

Dynamic of mode transition in air surface micro-discharge plasma: reactive species in confined space

Flexible surface micro-discharge plasma is a non-thermal plasma technique used for treating wounds in a painless way, with significant efficacy for chronic or hard-to-heal wounds. In this study, a confined space was designed to simulate wound conditions, with gelatin used to simulate wound tissue. The distinction between open and confined spaces was explored, and the effects of temperature, humidity, discharge power and the gap size within the confined space on the plasma characteristics were analyzed. It was found that temperature, humidity and discharge power are important factors that affect the concentration distribution of active components and the mode transition between ozone and nitrogen oxides. Compared to open space, the concentration of ozone in confined space was relatively lower, which facilitated the formation of nitrogen oxides. In open space, the discharge was dominated by ozone initially. As the temperature,humidity and discharge power increased, nitrogen oxides in the gas-phase products were gradually detected. In confined space, nitrogen oxides can be detected at an early stage and at much higher concentrations than ozone concentration. Furthermore, as the gap of the confined space decreased, the concentration of ozone was observed to decrease while that of nitrate increased, and the rate of this concentration change was further accelerated at higher temperature and higher power. It was shown that ozone concentration decreased from 0.11 to 0.03 μmol and the nitrate concentration increased from 20.5 to 24.5 μmol when the spacing in the confined space was reduced from 5 to 1 mm, the temperature of the external discharge was controlled at 40 ℃, and the discharge power was 12 W. In summary, this study reveals the formation and transformation mechanisms of active substances in air surface micro-discharge plasma within confined space, providing foundational data for its medical applications.

Assessing the possibility of using large language models in ocular surface diseases

AIM:To assess the possibility of using different large language models(LLMs)in ocular surface diseases by selecting five different LLMS to test their accuracy in answering specialized questions related to ocular surface diseases:ChatGPT-4,ChatGPT-3.5,Claude 2,PaLM2,and SenseNova.METHODS:A group of experienced ophthalmology professors were asked to develop a 100-question singlechoice question on ocular surface diseases designed to assess the performance of LLMs and human participants in answering ophthalmology specialty exam questions.The exam includes questions on the following topics:keratitis disease(20 questions),keratoconus,keratomalaciac,corneal dystrophy,corneal degeneration,erosive corneal ulcers,and corneal lesions associated with systemic diseases(20 questions),conjunctivitis disease(20 questions),trachoma,pterygoid and conjunctival tumor diseases(20 questions),and dry eye disease(20 questions).Then the total score of each LLMs and compared their mean score,mean correlation,variance,and confidence were calculated.RESULTS:GPT-4 exhibited the highest performance in terms of LLMs.Comparing the average scores of the LLMs group with the four human groups,chief physician,attending physician,regular trainee,and graduate student,it was found that except for ChatGPT-4,the total score of the rest of the LLMs is lower than that of the graduate student group,which had the lowest score in the human group.Both ChatGPT-4 and PaLM2 were more likely to give exact and correct answers,giving very little chance of an incorrect answer.ChatGPT-4 showed higher credibility when answering questions,with a success rate of 59%,but gave the wrong answer to the question 28% of the time.CONCLUSION:GPT-4 model exhibits excellent performance in both answer relevance and confidence.PaLM2 shows a positive correlation(up to 0.8)in terms of answer accuracy during the exam.In terms of answer confidence,PaLM2 is second only to GPT4 and surpasses Claude 2,SenseNova,and GPT-3.5.Despite the fact that ocular surface disease is a highly specialized discipline,GPT-4 still exhibits superior performance,suggesting that its potential and ability to be applied in this field is enormous,perhaps with the potential to be a valuable resource for medical students and clinicians in the future.

Response surface optimization of preparation parameters and evaluation of the antioxidant and antihypertensive activities of Spirulina protein hydrolysates

Safety,high protein content,and the numerous health benefits make Spirulina an outstanding source of bioactive peptides.Peptides from Spirulina,which exhibit antioxidant,anti-inflammatory,and antihypertensive effects,may assist in the management of cardiovascular diseases(CVDs).Here,we present the optimization of enzyme-digested hydrolysates derived from Spirulina sp.by using response surface methodology(RSM).We also evaluated the biological activity of Spirulina protein hydrolysates(SPHs)in contributing to the amelioration of hypertension and associated cardiovascular diseases.Our findings suggest that Spirulina protein extracts contain a complex proteinaceous composition with phycocyanin being the dominant protein,as evidenced by both SDS-PAGE and LC-MS/MS profiling.Alkaline protease,protease K,andα-chymotrypsin exhibited a substantial hydrolytic effect on Spirulina protein,taking into account their degree of hydrolysis(DH),peptide yield,and molecular weight distribution.Single-factor experiments identified pH,temperature,and enzyme/substrate ratio as the key factors influencing DH.Moreover,optimal hydrolysis conditions for the proteases were determined via RSM,leading to a considerable enhancement of the actual DH.Bioassays showed that SPHs have strong antioxidant activity against various free radicals,with a higher ability to scavenge hydroxyl radicals.Furthermore,SPHs inhibited macrophage nitric oxide secretion and significantly inhibited angiotensin I-converting enzyme in vitro at 400μg/mL.It is worth noting that SPHs prepared with protease K exhibited a potent anti-hypertensive effect in vivo.The findings indicate the potential usefulness of including dietary SPHs in preventing hypertension and associated CVDs.This research could be valuable in guiding the development of health-promoting foods within the Spirulina industry.

Clinical profile and outcomes of ocular surface squamous neoplasia at the Philippine General Hospital:a retrospective study

AIM:To evaluate the demographics,clinical characteristics,treatments,and outcomes of patients with ocular surface squamous neoplasia(OSSN)at the Philippine General Hospital.METHODS:This was a single-center,11-year retrospective,cross sectional case series on 18 cases of OSSN seen between January 2012 to June 2023.The patient’s demographics,presenting symptoms,tumor characteristics,histopathologic diagnosis,treatment,outcomes,and duration of follow-up were reviewed.RESULTS:Out of 33 identified cases of OSSN,only 18 were eligible for inclusion in the study.Mean age was 60.78y(range 31 to 80),with male predominance(66.67%).The left eye was most commonly affected(61.11%)with most presenting with fleshy mass(83.33%).Most tumors were located nasally(66.67%)and were predominantly papilliform(44.44%)in morphology with associated hyperpigmentation(38.89%).Squamous cell carcinoma(SCCA)was the most common histopathologic diagnosis(72.22%).The main primary treatment was surgical excision(94.44%)with or without adjunctive therapy,with only 1 patient undergoing first-line topical chemotherapy.Only 3 recurrences(16.67%)were noted with a median followup of 7.5mo.A statistically significant recurrence-free odds leaning towards the utilization of cryotherapy was noted.CONCLUSION:OSSN seen at the Philippine General Hospital is presented as a limbal papilliform mass,most commonly affecting elderly males.Surgical excision with adjuvant cryotherapy and/or chemotherapy is the preferred mode of treatment.

Surface integrity characterization of thirdgeneration nickel-based single crystal blade tenons after ultrasonic vibration-assisted grinding

Machined surface integrity of workpieces in harsh environments has a remarkable influence on their performance.However,the complexity of the new type of machining hinders a comprehensive understanding of machined surface integrity and its formation mechanism,thereby limiting the study of component performance.With increasing demands for high-quality machined workpieces in aerospace industry applications,researchers from academia and industry are increasingly focusing on post-machining surface characterization.The profile grinding test was conducted on a novel single-crystal superalloy to simulate the formation of blade tenons,and the obtained tenons were characterized for surface integrity elements under various operating conditions.Results revealed that ultrasonic vibration-assisted grinding(UVAG)led to multiple superpositions of abrasive grain trajectories,causing reduced surface roughness(an average reduction of approximately29.6%)compared with conventional grinding.After examining the subsurface layer of UVAG using transmission electron microscopy,the results revealed that the single-crystal tenon grinding subsurface layer exhibited a gradient evolution from the near-surface to the substrate.This evolution was characterized by an equiaxed nanocrystalline layer measuring 0.34μm,followed by a submicrocrystalline grain-forming zone spanning 0.6μm and finally,a constituent phase-twisted dis-torted deformation zone over 0.62μm.Under normal grinding conditions,the tenon exhibited low surface hardening(not exceeding 15%),and residual compressive stresses were observed on its surface.In cases where grinding burns occurred,a white layer appeared on the tenon's surface,which demonstrated varying thicknesses along the teeth from top to root due to thermal-force-structural coupling effects.Additionally,these burns introduced residual tensile stresses on the tenon's surface,potentially substantially affecting its fatigue life.This paper enhances our understanding of UVAG processes and establishes a foundation for their application in manufacturing singlecrystal turbine blades for next-generation aero-turbine engines.

Surface modification of fabrics using dielectric barrier discharge plasma for improved antifouling performance

Surface modification of fabrics is an effective way to endow them with antifouling properties while still maintaining their key advantages such as comfort,softness and stretchability.Herein,an atmospheric pressure dielectric barrier discharge(DBD)plasma method is demonstrated for the processing of silk fabrics using 1H,1H,2H,2H-perfluorodecyltriethoxysilane(PFDS)as the precursor.The results showed the successful grafting of PFDS groups onto the surface of silk fabrics without causing damage.Meanwhile,the gas temperature is rather low during the whole processing procedure,suggesting the non-equilibrium characteristics of DBD plasma.The influence on fabrics of the processing parameters(PFDS concentration,plasma treatment time and plasma discharge power)was systematically investigated.An optimum processing condition was determined to be a PFDS concentration of 8wt%,a plasma processing time of 40 s and a plasma power of 11.87 W.However,with prolonged plasma processing time or enhanced plasma power,the plasma-grafted PFDS films could be degraded.Further study revealed that plasma processing of silk fabrics with PFDS would lead to a change in their chemical composition and surface roughness.As a result,the surface energy of the fabrics was reduced,accompanied by improved water and oil repellency as well as enhanced antifouling performance.Besides,the plasma-grafted PFDS films also had good durability and stability.By extending the method to polyester and wool against different oil-/water-based stains,the DBD plasma surface modification technique demonstrated good versatility in improving the antifouling properties of fabrics.This work provides guidance for the surface modification of fabrics using DBD plasma to confer them with desirable functionalities.

Effect of surface crack on the bearing capacity of strip footing placed on rock mass

In hilly regions,the existence of surface cracks in rock mass induces a potential threat to structural stability.Thus,the present research aims to explore the impact of surface cracks on the loadbearing capacity of strip footing placed on the rock mass.By taking into account the various boundary constraints across the surface of crack edges,the study investigates the presence of two categories of surface cracks,namely(1)separated crack,and(2)fine crack.The lower bound limit analysis is employed in conjunction with the finite element method(LBFELA)to conduct the numerical analysis.In order to evaluate rock mass yielding,the power conic programming(PCP)method is utilized to implement the generalized Hoek-Brown(GHB)failure criterion.The stability of the strip footing is analyzed by determining the bearing capacity factor(Nσγ),which is presented in the form of design charts by varying the strength parameters of rock,including the Geological Strength Index(GSI),Hoek-Brown material parameter(mi),Disturbance factor(D),and Normalised Uniaxial Compressive Strength(σci/γB),whereγis the unit weight of rock mass,and B is the width of strip footing.The study also investigates the impact of cracks on strip footings,considering different positions of the crack(LC)and depths of the crack(DC).The results demonstrate that the influence of the fine crack is only noticeable until the LC/B ratio reaches 6.However,for the separated crack,its impact remains significant even when the LC/B ratio exceeds 16.The appearance of fine crack at the edge of the footing results in a decrease in the magnitude Nσγof up to 45%,indicating a substantial reduction in the stability of the footing.The failure patterns are presented and discussed in detail for various cases in this study to examine the effect of surface cracks on the strip footing and to address the extent of the plastic collapse.

Vibration safety assessment and parameter analysis of buried oil pipelines based on vibration isolation holes under strong surface impact

Strong surface impact will produce strong vibration,which will pose a threat to the safety of nearby buried pipelines and other important lifeline projects.Based on the verified numerical method,a comprehensive numerical parameter analysis is conducted on the key influencing factors of the vibration isolation hole(VIH),which include hole diameter,hole net spacing,hole depth,hole number,hole arrangement,and soil parameters.The results indicate that a smaller ratio of net spacing to hole diameter,the deeper the hole,the multi-row hole,the hole adoption of staggered arrangements,and better site soil conditions can enhance the efficiency of the VIH barrier.The average maximum vibration reduction efficiency within the vibration isolation area can reach 42.2%.The vibration safety of adjacent oil pipelines during a dynamic compaction projection was evaluated according to existing standards,and the measurement of the VIH was recommended to reduce excessive vibration.The single-row vibration isolation scheme and three-row staggered arrangement with the same hole parameters are suggested according to different cases.The research findings can serve as a reference for the vibration safety analysis,assessment,and control of adjacent underground facilities under the influence of strong surface impact loads.

Analysis of the redox environment and genesis of surface sediment in the northeast Indian Ocean at the Ninety-East Ridge

The Ninety-East Ridge(NER)is located in the semioceanic to oceanic region of the southern Bengal Fan in the Northeast Indian Ocean.The sedimentary environment,ocean currents,and scientific issues related to climate change have always been the focus of scientists.To well understand the sedimentary environment of the sea area,we studied the modern sedimentary environment of the NER by analyzing the redox-sensitive trace elements(RSEs)and biomarkers in the surface sediments of the northern region and both sides of the NER and the mechanism of their formation.The ratios of Mo/U(average 2.22),(Cu+Mo)/Zn(average 1.51),and the results ofδCe<1 of the sediment samples,all indicate the reduction of the sedimentary environment.In addition,the ratio of pristane(Pr)to phytane(Ph),C30diahopane to C30 hopane,and diasterane to sterane were low in all samples,on average of 1.03,0.9,and 0.33,respectively.The analysis of RSE and biomarker data revealed that the sedimentary environment on seabed of the NER is generally a rare low-oxygen reduction environment.Through the analysis of sediment characteristics,material sources,and ocean currents,we preliminarily constructed a genetic model for the low-oxygen reducing environment of surface sediments in the NER.We believe that the low-oxygen reduction environment of surface sediment in the NER could be influenced by multiple factors,such as terrestrial input of materials,productivity at sea surface,and sediment particle size.

Effect of sea surface temperature during critical early life history stages of Portunus trituberculatus on later yield

The early life stages of marine organisms are pivotal in shaping community dynamics and resource availability.In this study,we focused on Portunus trituberculatus,a crustacean integral to China's fisheries economy,and examined the effect of sea surface temperature(SST)in its critical early life stages on subsequent yields.To analyze the correlation between SST in different larval stages and the corresponding yield of P.trituberculatus,we simulated the transport and distribution of larvae from 2014 to 2022 by employing circulation models and Lagrangian particle tracking experiments(LPTE).In the five years(2014,2015,2016,2019,and 2020),particles were transported in a northwestern direction and moved in the direction of low SST.The distribution of particles in the megalopa stage(M stage)were located in the region of the lower temperature.In 2017,2018,and 2021,the particles were transported in a northeastern direction but they did not move with the gradient of low SST in these years,and the particles in the last M stage were located in the region where the SST was at the peak of the time period.In 2022,the distribution was observed for most of the particles in the southwestern part of Zhejiang coast,a small part of them were transported in the northwestern direction and a small amount of particles was distributed offshore along the northern area of the Zhejiang coast.The correlations between the SST at each stage of larvae with the corresponding year's yield showed that the yield of P.trituberculatus decreased significantly(R=-0.772,P=0.015)with increasing SST at the M stage.This study preliminarily explains the correlation between SST at the larval stage and the yield of P.trituberculatus and provides essential information for scientific stock enhancement in the future.

Electromagnetic Scattering from Two-Dimensional Rough Surface Using the Kirchhoff Approximation

A two-dimensional fractional Brown motion(fBm)fractal model is presented,which is suitable for describing the natural rough surface.Using the Kirchhoff approximation,the expressions of the electromagnetic scattering field and the normalized radar cross section from this fractal surface are obtained.Numerical results of the normalized radar cross section as a function of the fractal dimension,characteristic length and incidence frequency are given.Our fBm model is also compared with classical models of Gaussian and exponential correlation.