Reform of the Comprehensive Practical Course System for Mechanical and Electronic Engineering Majors Under the Background of New Engineering

Under the background of new engineering,the reform of the comprehensive practical course system for mechanical and electronic engineering majors actively responds to the challenges posed by the new round of technological revolution and industrial transformation to higher education,cultivating top-notch innovative intellectuals with comprehensive engineering qualities,meeting the requirements of being able to solve complex engineering problems rather than just cognitive capabilities,forming two core courses through reconstructing and reshaping the core courses of the major.The core courses include Drive,Measurement,and Control I and Drive,Measurement,and Control II,which highlight the comprehensive framework of mechanical and electronic engineering professional knowledge,continuing the comprehensive practical course system based on the unity of knowledge and practice,following the trend of new engineering,highlighting the practicality of professional innovation,assisting engineering education reform,and promoting high-quality development of new engineering professionals cultivation.

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.

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。

Defect engineering in transition-metal(Fe,Co,andNi)-based electrocatalysts for water splitting

Electrocatalytic water splitting seems to be an efficient strategy to deal with increasingly serious environmental problems and energy crises but still suffers from the lack of stable and efficient electrocatalysts.Designing practical electrocatalysts by introducing defect engineering,such as hybrid structure,surface vacancies,functional modification,and structural distortions,is proven to be a dependable solution for fabricating electrocatalysts with high catalytic activities,robust stability,and good practicability.This review is an overview of some relevant reports about the effects of defect engineering on the electrocatalytic water splitting performance of electrocatalysts.In detail,the types of defects,the preparation and characterization methods,and catalytic performances of electrocatalysts are presented,emphasizing the effects of the introduced defects on the electronic structures of electrocatalysts and the optimization of the intermediates'adsorption energy throughout the review.Finally,the existing challenges and personal perspectives of possible strategies for enhancing the catalytic performances of electrocatalysts are proposed.An in-depth understanding of the effects of defect engineering on the catalytic performance of electrocatalysts will light the way to design high-efficiency electrocatalysts for water splitting and other possible applications.

How Software Engineering Transforms Organizations: An Open and Qualitative Study on the Organizational Objectives and Motivations in Agile Transformations

Agile Transformations are challenging processes for organizations that look to extend the benefits of Agile philosophy and methods beyond software engineering.Despite the impact of these transformations on orga-nizations,they have not been extensively studied in academia.We conducted a study grounded in workshops and interviews with 99 participants from 30 organizations,including organizations undergoing transformations(“final organizations”)and companies supporting these processes(“consultants”).The study aims to understand the motivations,objectives,and factors driving and challenging these transformations.Over 700 responses were collected to the question and categorized into 32 objectives.The findings show that organizations primarily aim to achieve customer centricity and adaptability,both with 8%of the mentions.Other primary important objectives,with above 4%of mentions,include alignment of goals,lean delivery,sustainable processes,and a flatter,more team-based organizational structure.We also detect discrepancies in perspectives between the objectives identified by the two kinds of organizations and the existing agile literature and models.This misalignment highlights the need for practitioners to understand with the practical realities the organizations face.

The Application of Thermomechanical Dynamics (TMD) to Thermoelectric Energy Generation by Employing a Low Temperature Stirling Engine

A thermoelectric generation Stirling engine (TEG-Stirling engine) is discussed by employing a low temperature Stirling engine and the dissipative equation of motion derived from the method of thermomechanical dynamics (TMD). The results and mechanism of axial flux electromagnetic induction (AF-EMI) are applied to a low temperature Stirling engine, resulting in a TEG-Stirling engine. The method of TMD produced thermodynamically consistent and time-dependent physical quantities for the first time, such as internal energy ℰ(t), thermodynamic work Wth(t), the total entropy (heat dissipation) Qd(t)and measure or temperature of a nonequilibrium state T˜(t). The TMD analysis produced a lightweight mechanical system of TEG-Stirling engine which derives electric power from waste heat of temperature (40˚CT100˚C) by a thermoelectric conversion method. An optimal low rotational speed about 30θ′(t)/(2π)60(rpm) is found, applicable to devices for sustainable, clean energy technologies. The stability of a thermal state and angular rotations of TEG-Stirling engine are specifically shown by employing properties of nonequilibrium temperature T˜(t), which is also applied to study optimal fuel-injection and combustion timings of heat engines.

Model-Based Systems Engineering Approach to Design a Human Settlement to Better Serve Displaced People

The challenge of transitioning from temporary humanitarian settlements to more sustainable human settlements is due to a significant increase in the number of forcibly displaced people over recent decades, difficulties in providing social services that meet the required standards, and the prolongation of emergencies. Despite this challenging context, short-term considerations continue to guide their planning and management rather than more integrated, longer-term perspectives, thus preventing viable, sustainable development. Over the years, the design of humanitarian settlements has not been adapted to local contexts and perspectives, nor to the dynamics of urbanization and population growth and data. In addition, the current approach to temporary settlement harms the environment and can strain limited resources. Inefficient land use and ad hoc development models have compounded difficulties and generated new challenges. As a result, living conditions in settlements have deteriorated over the last few decades and continue to pose new challenges. The stakes are such that major shortcomings have emerged along the way, leading to disruption, budget overruns in a context marked by a steady decline in funding. However, some attempts have been made to shift towards more sustainable approaches, but these have mainly focused on vague, sector-oriented themes, failing to consider systematic and integration views. This study is a contribution in addressing these shortcomings by designing a model-driving solution, emphasizing an integrated system conceptualized as a system of systems. This paper proposes a new methodology for designing an integrated and sustainable human settlement model, based on Model-Based Systems Engineering and a Systems Modeling Language to provide valuable insights toward sustainable solutions for displaced populations aligning with the United Nations 2030 agenda for sustainable development.

Exploration of the Integration of Software Engineering Thinking into Embedded System Design Course

Engineering practice is the key bridge between college education and actual work in the industry.In order to deliver qualified talents with engineering quality to the industry,this paper explores integrating software engineering thinking into the Embedded System Design course.A practical and effective teaching mode is designed consisting of immersive learning,case-based learning,progressive practice,interactive learning,and autonomous learning.Through this teaching mode,multi-levels of closed-loop have been established including final project cycle closed-loop,testing cycle closed-loop,and product cycle closed-loop.During this process,students gradually transition to putting forward product requirements,carrying out design and development,thinking and solving problems,collaborating,and assuring quality from the perspective of software engineering.The practice results show that students’engineering quality has been significantly improved.

Crack Prevention and Management Strategies in Bridge Engineering Construction

Cracking during construction is a common occurrence in modern bridge engineering that can directly impact the overall safety of the bridge.Therefore,it is essential to focus on preventing and controlling cracks.As the construction technology for bridge engineering has evolved,the internal quality of construction has significantly improved.However,the appearance quality remains a crucial factor that reflects the technical expertise of a construction company.Therefore,minimizing cracks and improving the appearance quality of concrete are critical issues that require the attention of construction units,supervision departments,and construction companies.This article will analyze the causes of cracking and suggest corresponding prevention and treatment methods.

A Discussion on Innovative Methods for Green Engineering Management in Construction Engineering

With the rapid development of society,the construction industry has made significant progress.However,as environmental issues intensify,many construction projects contribute to pollution.In this context,applying green project management methods in construction can enhance energy conservation and environmental protection,reduce energy consumption and costs,and minimize environmental damage,promoting balanced development between the environment and the economy.Therefore,integrating green construction concepts into current construction projects is essential.Based on project requirements and construction activities,effective green project management strategies should be developed to improve management standards and promote more efficient green construction.This paper analyzes green project management in construction engineering and offers recommendations for reference.

Research on the Reform of Practical Teaching of Internet of Things Engineering in the Context of New Engineering

The emergence of new engineering disciplines has resulted in the growing trend of cross-discipline,and the enhancement of students’technical application ability has become the main teaching objective of engineering disciplines.For this reason,the Internet of Things(IoT)engineering program should be actively reformed,providing students with sufficient opportunities to improve their practical skills.This paper identifies the challenges within practical teaching of IoT engineering,delves into effective strategies for practical IoT teaching within the context of emerging engineering disciplines,and presents practical teaching experiences from the School of Information Engineering at Hainan University of Science and Technology as a case study.The aim is to offer guidance and insights to educators in this field.

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。

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.

Interface Engineering of Titanium Nitride Nanotube Composites for Excellent Microwave Absorption at Elevated Temperature

Currently,the microwave absorbers usually suffer dreadful electromagnetic wave absorption(EMWA)performance damping at elevated temperature due to impedance mismatching induced by increased conduction loss.Consequently,the development of high-performance EMWA materials with good impedance matching and strong loss ability in wide temperature spectrum has emerged as a top priority.Herein,due to the high melting point,good electrical conductivity,excellent environmental stability,EM coupling effect,and abundant interfaces of titanium nitride(TiN)nanotubes,they were designed based on the controlling kinetic diffusion procedure and Ostwald ripening process.Benefiting from boosted heterogeneous interfaces between TiN nanotubes and polydimethylsiloxane(PDMS),enhanced polarization loss relaxations were created,which could not only improve the depletion efficiency of EMWA,but also contribute to the optimized impedance matching at elevated temperature.Therefore,the TiN nanotubes/PDMS composite showed excellent EMWA performances at varied temperature(298-573 K),while achieved an effective absorption bandwidth(EAB)value of 3.23 GHz and a minimum reflection loss(RLmin)value of−44.15 dB at 423 K.This study not only clarifies the relationship between dielectric loss capacity(conduction loss and polarization loss)and temperature,but also breaks new ground for EM absorbers in wide temperature spectrum based on interface engineering.

Decade Milestone Advancement of Defect-Engineered g-C_(3)N_(4) for Solar Catalytic Applications

Over the past decade, graphitic carbon nitride(g-C_(3)N_(4)) has emerged as a universal photocatalyst toward various sustainable carbo-neutral technologies. Despite solar applications discrepancy, g-C_(3)N_(4) is still confronted with a general fatal issue of insufficient supply of thermodynamically active photocarriers due to its inferior solar harvesting ability and sluggish charge transfer dynamics. Fortunately, this could be significantly alleviated by the “all-in-one” defect engineering strategy, which enables a simultaneous amelioration of both textural uniqueness and intrinsic electronic band structures. To this end, we have summarized an unprecedently comprehensive discussion on defect controls including the vacancy/non-metallic dopant creation with optimized electronic band structure and electronic density, metallic doping with ultraactive coordinated environment(M–N_(x), M–C_(2)N_(2), M–O bonding), functional group grafting with optimized band structure, and promoted crystallinity with extended conjugation π system with weakened interlayered van der Waals interaction. Among them, the defect states induced by various defect types such as N vacancy, P/S/halogen dopants, and cyano group in boosting solar harvesting and accelerating photocarrier transfer have also been emphasized. More importantly, the shallow defect traps identified by femtosecond transient absorption spectra(fs-TAS) have also been highlighted. It is believed that this review would pave the way for future readers with a unique insight into a more precise defective g-C_(3)N_(4) “customization”, motivating more profound thinking and flourishing research outputs on g-C_(3)N_(4)-based photocatalysis.

Ionization Engineering of Hydrogels Enables Highly Efficient Salt‑Impeded Solar Evaporation and Night‑Time Electricity Harvesting

Interfacial solar evaporation holds immense potential for brine desalination with low carbon footprints and high energy utilization.Hydrogels,as a tunable material platform from the molecular level to the macroscopic scale,have been considered the most promising candidate for solar evaporation.However,the simultaneous achievement of high evaporation efficiency and satisfactory tolerance to salt ions in brine remains a challenging scientific bottleneck,restricting the widespread application.Herein,we report ionization engineering,which endows polymer chains of hydrogels with electronegativity for impeding salt ions and activating water molecules,fundamentally overcoming the hydrogel salt-impeded challenge and dramatically expediting water evaporating in brine.The sodium dodecyl benzene sulfonate-modified carbon black is chosen as the solar absorbers.The hydrogel reaches a ground-breaking evaporation rate of 2.9 kg m−2 h−1 in 20 wt%brine with 95.6%efficiency under one sun irradiation,surpassing most of the reported literature.More notably,such a hydrogel-based evaporator enables extracting clean water from oversaturated salt solutions and maintains durability under different high-strength deformation or a 15-day continuous operation.Meantime,on the basis of the cation selectivity induced by the electronegativity,we first propose an all-day system that evaporates during the day and generates salinity-gradient electricity using waste-evaporated brine at night,anticipating pioneer a new opportunity for all-day resource-generating systems in fields of freshwater and electricity.

Biomaterials and tissue engineering in traumatic brain injury:novel perspectives on promoting neural regeneration

Traumatic brain injury is a serious medical condition that can be attributed to falls, motor vehicle accidents, sports injuries and acts of violence, causing a series of neural injuries and neuropsychiatric symptoms. However, limited accessibility to the injury sites, complicated histological and anatomical structure, intricate cellular and extracellular milieu, lack of regenerative capacity in the native cells, vast variety of damage routes, and the insufficient time available for treatment have restricted the widespread application of several therapeutic methods in cases of central nervous system injury. Tissue engineering and regenerative medicine have emerged as innovative approaches in the field of nerve regeneration. By combining biomaterials, stem cells, and growth factors, these approaches have provided a platform for developing effective treatments for neural injuries, which can offer the potential to restore neural function, improve patient outcomes, and reduce the need for drugs and invasive surgical procedures. Biomaterials have shown advantages in promoting neural development, inhibiting glial scar formation, and providing a suitable biomimetic neural microenvironment, which makes their application promising in the field of neural regeneration. For instance, bioactive scaffolds loaded with stem cells can provide a biocompatible and biodegradable milieu. Furthermore, stem cells-derived exosomes combine the advantages of stem cells, avoid the risk of immune rejection, cooperate with biomaterials to enhance their biological functions, and exert stable functions, thereby inducing angiogenesis and neural regeneration in patients with traumatic brain injury and promoting the recovery of brain function. Unfortunately, biomaterials have shown positive effects in the laboratory, but when similar materials are used in clinical studies of human central nervous system regeneration, their efficacy is unsatisfactory. Here, we review the characteristics and properties of various bioactive materials, followed by the introduction of applications based on biochemistry and cell molecules, and discuss the emerging role of biomaterials in promoting neural regeneration. Further, we summarize the adaptive biomaterials infused with exosomes produced from stem cells and stem cells themselves for the treatment of traumatic brain injury. Finally, we present the main limitations of biomaterials for the treatment of traumatic brain injury and offer insights into their future potential.

基于Google Earth Engine的前郭县春季农田覆膜提取

本文基于Google Earth Engine(GEE)云平台,综合考虑光学影像的波段反射率、光谱指数特征和雷达影像的极化、纹理特征,分别构建仅使用光学特征、仅使用雷达特征以及光学和雷达特征组合3种特征输入组合;根据精度确定最佳输入特征后,分别结合机器学习中的分类与回归树、支持向量机、最小距离分类法、梯度提升树和随机森林5种方法建立覆膜提取模型,依据结果精度评估不同方法的性能,并基于最优化模型提取出最终的覆膜农田面积。结果表明:①最佳输入特征为波段反射率特征+光谱指数特征+极化特征+纹理特征;②采用随机森林方法建立的模型精度最高,研究区I的总体精度达到了95.84%,Kappa系数为0.95,地物错分率为1.2%,明显优于其他4种方法(地物错分率较分类与回归树、支持向量机、最小距离和梯度提升树法降低0.8%、7.3%、38.0%和0.3%),研究区II的验证精度达到了87.84%,证明该模型在覆膜提取中可以取得更加准确的结果;③使用本文方法得到2022年研究区I覆膜农田面积为1302.48 km2,估算地膜使用量约为7585.62 t。本文综合考虑光学和雷达影像在地物识别中的特点建立模型,可以准确、高效的识别农田地膜,掌握地膜面积,对环境治理与防治具有重要意义。

基于Google Earth Engine和Sentinel-2数据的耕地分类研究

【目的】采用遥感影像对不同种类农作物耕地进行高效精准的分类,以期获取最优的农作物种植信息提取方案,为农业生产提质增效提供决策支持。【方法】以陕西省宝鸡市扶风县为研究区,利用Google Earth Engine(GEE)平台,基于2020年10月至2021年12月的Sentinel-2影像和目视解译与野外定位相结合选取的样本点,使用随机森林(random forest,RF)算法,结合归一化植被指数(normalized difference vegetation index,NDVI)、增强植被指数(enhanced vegetation index,EVI)、物候参数特征、遥感影像红边波段,且将根据NDVI计算出的物候参数的波段记为N,根据EVI计算出的物候参数的波段记为E,引入红边波段记为1,未引入红边波段记为2,在此基础上构建了8种不同的分类模型(NDVI-N1、EVI-E1、N1、E1、NDVI-N2、EVI-E2、N2、E2),并与4种样本分割比例(训练样本数与检验样本数的比例分别为5∶5,6∶4,7∶3和8∶2)组合,共计32种分类方案,利用这些方案对扶风县的不同种类农作物耕地进行分类,并计算了不同分类方案的总体精度和Kappa系数。【结果】(1)经S-G滤波法处理后,6种地物类型的NDVI和EVI时序曲线噪声减小且更为平滑,且NDVI和EVI曲线差异明显。(2)在32种分类方案中,只有样本分割比例为7∶3时的EVI-E1模型、EVI-E2模型和样本分割比例为6∶4时E2模型的总体精度高于90%,说明在扶风地区用EVI分类效果更好一些。(3)在样本分割比例为7∶3的情况下,EVI-E1模型的总体精度和Kappa系数均最高,分别为91.66%和89.41%,为最优分类方案。但是在该方案中引入红边波段后,其总体精度下降了1.18%,Kappa系数下降了1.53%,可知运用该分类方案时应剔除红边波段。(4)运用最优分类方案对小麦地、玉米地、土豆地的提取结果与实际调查情况大致相同。【结论】基于GEE平台和Sentinel-2数据实现了对县域级农作物种植面积的精确分类,可为扶风县农业生产提供决策支持。