Optimizing electronic structure through point defect engineering for enhanced electrocatalytic energy conversion

Point defect engineering endows catalysts with novel physical and chemical properties,elevating their electrocatalytic efficiency.The introduction of defects emerges as a promising strategy,effectively modifying the electronic structure of active sites.This optimization influences the adsorption energy of intermediates,thereby mitigating reaction energy barriers,altering paths,enhancing selectivity,and ultimately improving the catalytic efficiency of electrocatalysts.To elucidate the impact of defects on the electrocatalytic process,we comprehensively outline the roles of various point defects,their synthetic methodologies,and characterization techniques.Importantly,we consolidate insights into the relationship between point defects and catalytic activity for hydrogen/oxygen evolution and CO_(2)/O_(2)/N_(2) reduction reactions by integrating mechanisms from diverse reactions.This underscores the pivotal role of point defects in enhancing catalytic performance.At last,the principal challenges and prospects associated with point defects in current electrocatalysts are proposed,emphasizing their role in advancing the efficiency of electrochemical energy storage and conversion materials.

Morphology engineering of ZnO micro/nanostructures under mild conditions for optoelectronic application

Zinc oxide(ZnO)serves as a crucial functional semiconductor with a wide direct bandgap of approximately 3.37 eV.Solvothermal reaction is commonly used in the synthesis of ZnO micro/nanostructures,given its low cost,simplicity,and easy implementation.Moreover,ZnO morphology engineering has become desirable through the alteration of minor conditions in the reaction process,particularly at room temperature.In this work,ZnO micro/nanostructures were synthesized in a solution by varying the amounts of the ammonia added at low temperatures(including room temperature).The formation of Zn^(2+)complexes by ammonia in the precursor regulated the reaction rate of the morphology engineering of ZnO,which resulted in various structures,such as nanoparticles,nanosheets,microflowers,and single crystals.Finally,the obtained ZnO was used in the optoelectronic application of ultraviolet detectors.

Defect Engineering with Rational Dopants Modulation for High‑Temperature Energy Harvesting in Lead‑Free Piezoceramics

High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,including high figure of merit(FOM),insulation resistivity(ρ)and depolarization temperature(Td)are indispensable but hard to achieve in lead-free piezoceramics,especially operating at 250°C has not been reported before.Herein,well-balanced performances are achieved in BiFeO3–BaTiO3 ceramics via innovative defect engineering with respect to delicate manganese doping.Due to the synergistic effect of enhancing electrostrictive coefficient by polarization configuration optimization,regulating iron ion oxidation state by high valence manganese ion and stabilizing domain orientation by defect dipole,comprehensive excellent electrical performances(Td=340°C,ρ250°C>10^(7)Ωcm and FOM_(250°C)=4905×10^(–15)m^(2)N^(−1))are realized at the solid solubility limit of manganese ions.The HT-PEHs assembled using the rationally designed piezoceramic can allow for fast charging of commercial electrolytic capacitor at 250°C with high energy conversion efficiency(η=11.43%).These characteristics demonstrate that defect engineering tailored BF-BT can satisfy high-end HT-PEHs requirements,paving a new way in developing selfpowered wireless sensors working in HT environments.

Defect Engineering:Can it Mitigate Strong Coulomb Effect of Mg^(2+)in Cathode Materials for Rechargeable Magnesium Batteries?

Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.

Utilizing engineered extracellular vesicles as delivery vectors in the management of ischemic stroke:a special outlook on mitochondrial delivery

Ischemic stroke is a secondary cause of mortality worldwide,imposing considerable medical and economic burdens on society.Extracellular vesicles,serving as natural nanocarriers for drug delivery,exhibit excellent biocompatibility in vivo and have significant advantages in the management of ischemic stroke.However,the uncertain distribution and rapid clearance of extracellular vesicles impede their delivery efficiency.By utilizing membrane decoration or by encapsulating therapeutic cargo within extracellular vesicles,their delivery efficacy may be greatly improved.Furthermore,previous studies have indicated that microvesicles,a subset of large-sized extracellular vesicles,can transport mitochondria to neighboring cells,thereby aiding in the restoration of mitochondrial function post-ischemic stroke.Small extracellular vesicles have also demonstrated the capability to transfer mitochondrial components,such as proteins or deoxyribonucleic acid,or their sub-components,for extracellular vesicle-based ischemic stroke therapy.In this review,we undertake a comparative analysis of the isolation techniques employed for extracellular vesicles and present an overview of the current dominant extracellular vesicle modification methodologies.Given the complex facets of treating ischemic stroke,we also delineate various extracellular vesicle modification approaches which are suited to different facets of the treatment process.Moreover,given the burgeoning interest in mitochondrial delivery,we delved into the feasibility and existing research findings on the transportation of mitochondrial fractions or intact mitochondria through small extracellular vesicles and microvesicles to offer a fresh perspective on ischemic stroke therapy.

Geographical Engineering and Its Role in Promoting Integrated Geography Research

Throughout the contemporary Chinese history of geography,geographical engineering has consistently played a pivotal role as a fundamental scientific activity.It possesses its distinct ontological basis and value orientation,rendering it inseparable from being merely a derivative of geographical science or technology.This paper defines geographical engineering and introduces its development history through the lens of Chinese geographical engineering praxises.Furthermore,it is highlighted the logical and functional consistency between the theory of human-earth system and the praxis of geographical engineering.Six modern cases of geographical engineering projects are presented in detail to demonstrate the points and characteristics of different types of modern geographical engineering.Geographical engineering serves as an engine for promoting integrated geography research,and in response to the challenge posed by fragmented geographies,this paper advocates for an urgent revitalization of geographical engineering.The feasibility of revitalizing geographical engineering is guaranteed because it aligns with China’s national strategies.

Targeting capabilities of engineered extracellular vesicles for the treatment of neurological diseases

Recent advances in research on extracellular vesicles have significantly enhanced their potential as therapeutic agents for neurological diseases.Owing to their therapeutic properties and ability to cross the blood–brain barrier,extracellular vesicles are recognized as promising drug delivery vehicles for various neurological conditions,including ischemic stroke,traumatic brain injury,neurodegenerative diseases,glioma,and psychosis.However,the clinical application of natural extracellular vesicles is hindered by their limited targeting ability and short clearance from the body.To address these limitations,multiple engineering strategies have been developed to enhance the targeting capabilities of extracellular vesicles,thereby enabling the delivery of therapeutic contents to specific tissues or cells.Therefore,this review aims to highlight the latest advancements in natural and targeting-engineered extracellular vesicles,exploring their applications in treating traumatic brain injury,ischemic stroke,Parkinson's disease,Alzheimer's disease,amyotrophic lateral sclerosis,glioma,and psychosis.Additionally,we summarized recent clinical trials involving extracellular vesicles and discussed the challenges and future prospects of using targeting-engineered extracellular vesicles for drug delivery in treating neurological diseases.This review offers new insights for developing highly targeted therapies in this field.

Effect of Nozzle Inclination Angle on Fuel-Air Mixing and Combustion in a Heavy Fuel Engine

Heavy-fuel engines are widely used in UAVs(Unmanned Autonomous Vehicles)because of their reliability and high-power density.In this study,a combustion model for an in-cylinder direct injection engine has been imple-mented using the AVL FIRE software.The effects of the angle of nozzle inclination on fuel evaporation,mixture distribution,and combustion in the engine cylinder have been systematically studied at 5500 r/min and consider-ing full load cruise conditions.According to the results,as the angle of nozzle inclination increases,the maximum combustion explosion pressure in the cylinderfirst increases and then it decreases.When the angle of nozzle incli-nation is less than 45°,the quality of the mixture in the cylinder and the combustion performance can be improved by increasing the angle.When the angle of nozzle inclination is greater than 45°,however,the mixture unevenness increases slightly with the angle,leading to a deterioration of the combustion performances.When the angle of nozzle inclination is between 35°and 55°,the overall combustion performance of the engine is rela-tively good.When the angle of nozzle inclination is 45°,the combustion chamber’s geometry and the cylinder’s airflow are well matched with the fuel spray,and the mixture quality is the best.Compared with 25°,the peak heat release rate increases by 20%,and the maximum combustion burst pressure increases by 5.5%.

Simulation Study of Diesel Spray Tilt Angle and Ammonia Energy Ratio Effect on Ammonia-Diesel Dual-Fuel Engine Performance

Ammonia-diesel dual fuel(ADDF)engines for transportation applications are an important way to reduce carbon emissions.In order to achieve better combustion of ammonia in diesel engines.A small-bore single-cylinder engine was converted into an ADDF engine with the help of mature computational fluid dynamics(CFD)simulation software to investigate the performance of an engine with a high ammonia energy ratio(AER),and to study the effect of spray tilt angle on ADDF engine.The results showed that the increase in AER reduced nitric oxide(NO)and nitrogen dioxide(NO2)emissions but increased nitrous oxide(N2O)and unburned ammonia emissions.AER in the range of 50%-70%achieved lower greenhouse gases(GHG)emissions than the pure diesel mode.Relative to the pure diesel mode,when the AER was 60%,the indicated thermal efficiency(ITE)was increased by 0.2%and the GHG emissions were decreased by 22.3%,but carbon monoxide(CO)and Hydrocarbon(HC)emissions were increased.Increasing the in-cylinder combustion temperature or high-temperature region range of the ADDF engine could reduce GHG emissions.At an AER of 60%,an increase in the spray tilt angle helped the ammonia combustion in the residual gap to reduce the unburned ammonia emissions.Compared to the pure diesel mode with a spray tilt angle of 75°,an AER of 60%with a spray tilt angle of 77.5°improved the ITE by 1.5%,and reduced theGHGemissions by 25.7%.Adjusting the spray tilt angle of theADDFengine also reducedCOandHCemissions.This is an effective way to improve ADDF engine performance by adjusting the spray tilt angle.

Teaching Reform of Environmental Engineering Microbiology Based on OBE Concept in the Context of New Engineering Disciplines

In response to meeting the needs of cultivating applied talents in the construction of new engineering disciplines,based on the concept of Outcome-Based Education(OBE),this study analyzes the problems existing in the teaching of the course Environmental Engineering Microbiology,and put forward some corresponding curriculum reform schemes.According to the target points of professional graduation requirements,the scheme proposes revising the syllabus of Environmental Engineering Microbiology,clarifying the curriculum objectives,updating the teaching content,and reforming the teaching methods.Through these measures,it is intended to achieve the unity of teachers way of"teaching"and students way of"learning",construct a new teaching mode,fully stimulate students subjective initiative,and enhance students innovative consciousness and practical ability.Besides,in this study,a"whole process-diversification"evaluation system is established to comprehensively evaluate students performance in theoretical knowledge learning and practical application,comprehensively evaluate students learning situation,and analyze the teaching effect in real time,so as to achieve continuous improvement,and ultimately achieve the goal of improving classroom quality.

Characterization and correlation of engineering properties with microstructure in peanuts:A microscopic to macroscopic analysis

Peanut varieties are diverse globally,with their characters and nutrition determining the product quality.However,the comparative analysis and statistical analysis of key quality indicators for peanut kernels across the world remains relatively limited,impeding the comprehensive evaluation of peanut quality and hindering the industry development on a global scale.This study aimed to compare and analyze the apparent morphology,microstructure,single-cell structure,engineering and mechanical properties,as well as major nutrient contents of peanut kernels from 10 different cultivars representing major peanut-producing countries.The surface and cross-section microstructure of the peanut kernels exhibited a dense“blocky”appearance with a distinct cellular structure.The lipid droplets were predominantly spherical with a regular distribution within the cells.The single-cell structure of the kernels from these 10 peanut cultivars demonstrated varying morphologies and dimensions,which exhibited correlations with their mechanical and engineering properties.Furthermore,the mass loss versus temperature profiles of the peanut kernels revealed five distinct stages,corresponding to moisture loss,volatile loss,protein denaturation,and the degradation of various biomacromolecules.Variations were also observed in the lipid,protein,and sucrose contents,texture,bulk density,true density,porosity,geometric mean diameter,and sphericity among the diferent peanut varieties.This study establishes relationships and correlations among microstructure,engineering properties,and nutritional composition of commonly grown peanut varieties in major peanut-processing countries.The findings provide valuable insights into peanut quality evaluation,empowering the peanut industry to enhance their processing and product development efforts.

Kinked Rebar and Engineering Structures Applying Kinked Materials:State-ofthe-Art Review

Kinked rebar is a special type of steel material,which is installed in beam column nodes and frame beams.It effectively enhances the blast resilience,seismic collapse resistance,and progressive collapse resistance of reinforced concrete(RC)structures without imposing substantial cost burdens,thereby emerging as a focal point of recent research endeavors.On the basis of explaining the working principle of kinked rebars,this paper reviews the research status of kinked rebars at home and abroad from three core domains:the tensile mechanical properties of kinked rebars,beam column nodes with kinked rebars,and concrete frame structures with kinked rebars.The analysis underscores that the straightening process of kinked rebars does not compromise their ultimate strength but significantly bolsters structural ductility and enhances energy dissipation capabilities.In beam-column joints,the incorporation of kinked rebars facilitates the seamless transfer of plastic hinges,adhering to the design principle of“strong columns and weak beams.”In addition,kinked rebars can greatly improve the resistance of the beam;The seismic resistance,internal explosion resistance,and progressive collapse resistance of reinforced concrete frame structures with kinked rebar have significantly improved.Beyond its primary application,the principle of kinked rebar was extended to other applications of kinked materials such as corrugated steel plates and origami structures,and the stress characteristics of related components and structures were studied.Intriguingly,this paper also proposes the application of kinked rebars in bridge engineering,aiming to address the challenges of localized damage concentration and excessive residual displacement in RC bridge piers.The introduction of kinked rebars in piers is envisioned to mitigate these issues,with the paper outlining its advantages and feasibility,thereby offering valuable insights for future research on kinked reinforcement and seismic design strategies for bridges.

基于Google Earth Engine的1985~2023年蒙古国地表水体的时空变化分析

水是人类社会发展生产的基础资源。随着遥感技术与云计算技术的不断发展,谷歌地球引擎(Google Earth Engine,GEE)平台成为了大规模和长期的地表水体分析与制图的重要手段。采用Landsat 5TM和Landsat 8OLI卫星数据,分析了1985~2023年6月至9月的蒙古国地表水体的时空变化特征。研究结果表明,1985~2023年蒙古国地表水体的面积呈下降趋势,稳定水体面积从15547.71km2缩减至14452.13km^(2)。其中,大型水体保持相对稳定,主要是小型湖泊和河流发生变化。本文的分析结果为深入了解蒙古国的生态环境变化提供了重要的基础,并为准确预测蒙古国未来的水资源和环境变化以及水资源的有效管理和保护提供了方向。

基于C#语言与ArcGIS Engine 的开采沉陷预计系统开发

为了预计煤层开采引发的地表移动变形,基于极坐标系的概率积分法,借助C#语言和ArcGIS Engine组件工具库设计开发了矿区开采沉陷预计系统。开采沉陷预计系统适用于不规则形状的开采工作面,能够对开采区域地表各点不同开采时间后的下沉、水平移动、水平变形、倾斜、曲率进行预计,并对预计结果进行后处理,绘制地表移动变形云图。以陕西省某矿308工作面开采为例,根据工作面的开采条件、地层岩性等特征选取概率积分参数并代入本系统进行地表移动变形预计,将结果与实测地表移动变形进行对比分析。结果表明:使用该系统预计的地表下沉值与实测下沉值的相对误差小于10%,且下沉盆地形态与实际基本吻合,该系统的预计结果较为可靠,对矿区的开采沉陷预计具有一定的适用性。

Multidimensional Modeling of Fuel Spray, Combustion and Emissions of F912Q Diesel Engine

A computational fluid dynamics (CFD) study was carried out on a four stroke air cooled DI diesel engine, F912Q manufactured by Beinei Company, by using the KIVA 3V code. A three dimensional mesh was set up to model the cylinder, intake passage and exhaust passage. The calculated in cylinder pressure history and emissions are compared with the engine test data. The results show reasonable agreement. The effects of swirl ratio and spray angle on fuel spray, evaporation and mixing are investigated. It is found that there are optimum swirl ratio and spray angle for better evaporation and combustion.

Experimental Study of Diesel-NG Dual Fuel Electronic System for F6L912Q Engine

In order to improve the diesel engine emission performance and convert the diesel engine to dual fuel engine, a dual fuel (diesel and compressed natural gas (CNG)) electronic system was developed, in which electromagnetic valves were used to control multi point natural gas injection. The system was designed for type F6L912Q diesel engine and the function of the system was testified on test cell. The test results showed that the system had great advantages in power ability and emission performance. The average CNG substitution at rated load was over 80%. The dual fuel system was practical. To adopt dual fuel system was a good way to improve the engine's emission performance.

基于Google earth engine渭-库绿洲果园遥感提取

针对干旱区果园大面积遥感提取困难、识别精度低等问题,本研究基于GEE(Google earth engine)平台,综合应用Sentinel-1/Sentinel-2影像构建特征集。通过对比原始特征组合、Jeffries-Matusita(J-M)距离、属性重要度3种优化方式,结合随机森林(Random forest,RF)分类方法,对比得到最佳优化方式,探索果园最优分类特征集。结果表明:识别效果最好的方案为G17 JM,总体精度为91.25%,kappa系数为0.89,面积精度为82.55%。最优特征集为B8_asm、B8_ent、B8_idm、NDVI re3、B6、B7、a、e、b、EVI、B11、B8A、B8、VV。使用J-M距离进行特征集优化,有效降低数据量、提高计算效率,更有利于精确遥感识别果园种植面积。表明GEE快速、准确获取果园种植面积的可行性,为获取果园动态变化提供强有力的基础。

基于Unreal Engine的虚拟现实技术在元宇宙图书馆中的应用

以虚拟现实技术作为研究切入点,探索元宇宙图书馆建设的技术实现路径。通过文献调研对比分析现有的虚拟现实技术,寻找一种适合高校图书馆自主研发的技术实现方法,并通过具体案例验证该方法的现实可行性。研究发现基于Unreal Engine的虚拟现实技术具有低成本、低代码量、可扩展等优点,适合经费少、计算机人才短缺的高校图书馆。对高校图书馆推进元宇宙图书馆建设具有一定的参考价值。

Compositional and Hollow Engineering of Silicon Carbide/Carbon Microspheres as High-Performance Microwave Absorbing Materials with Good Environmental Tolerance

Microwave absorbing materials(MAMs)characterized by high absorption efficiency and good environmental tolerance are highly desirable in practical applications.Both silicon carbide and carbon are considered as stable MAMs under some rigorous conditions,while their composites still fail to produce satisfactory microwave absorption performance regardless of the improvements as compared with the individuals.Herein,we have successfully implemented compositional and structural engineering to fabricate hollow Si C/C microspheres with controllable composition.The simultaneous modulation on dielectric properties and impedance matching can be easily achieved as the change in the composition of these composites.The formation of hollow structure not only favors lightweight feature,but also generates considerable contribution to microwave attenuation capacity.With the synergistic effect of composition and structure,the optimized SiC/C composite exhibits excellent performance,whose the strongest reflection loss intensity and broadest effective absorption reach-60.8 dB and 5.1 GHz,respectively,and its microwave absorption properties are actually superior to those of most SiC/C composites in previous studies.In addition,the stability tests of microwave absorption capacity after exposure to harsh conditions and Radar Cross Section simulation data demonstrate that hollow SiC/C microspheres from compositional and structural optimization have a bright prospect in practical applications.

Biomimetic natural biomaterials for tissue engineering and regenerative medicine:new biosynthesis methods,recent advances,and emerging applications

Biomimetic materials have emerged as attractive and competitive alternatives for tissue engineering(TE)and regenerative medicine.In contrast to conventional biomaterials or synthetic materials,biomimetic scaffolds based on natural biomaterial can offer cells a broad spectrum of biochemical and biophysical cues that mimic the in vivo extracellular matrix(ECM).Additionally,such materials have mechanical adaptability,micro-structure interconnectivity,and inherent bioactivity,making them ideal for the design of living implants for specific applications in TE and regenerative medicine.This paper provides an overview for recent progress of biomimetic natural biomaterials(BNBMs),including advances in their preparation,functionality,potential applications and future challenges.We highlight recent advances in the fabrication of BNBMs and outline general strategies for functionalizing and tailoring the BNBMs with various biological and physicochemical characteristics of native ECM.Moreover,we offer an overview of recent key advances in the functionalization and applications of versatile BNBMs for TE applications.Finally,we conclude by offering our perspective on open challenges and future developments in this rapidly-evolving field.