Harness High-Temperature Thermal Energy via Elastic Thermoelectric Aerogels

Despite notable progress in thermoelectric(TE)materials and devices,developing TE aerogels with high-temperature resistance,superior TE performance and excellent elasticity to enable self-powered high-temperature monitoring/warning in industrial and wearable applications remains a great challenge.Herein,a highly elastic,flame-retardant and high-temperature-resistant TE aerogel,made of poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate)/single-walled carbon nanotube(PEDOT:PSS/SWCNT)composites,has been fabricated,displaying attractive compression-induced power factor enhancement.The as-fabricated sensors with the aerogel can achieve accurately pressure stimuli detection and wide temperature range monitoring.Subsequently,a flexible TE generator is assembled,consisting of 25 aerogels connected in series,capable of delivering a maximum output power of 400μW when subjected to a temperature difference of 300 K.This demonstrates its outstanding high-temperature heat harvesting capability and promising application prospects for real-time temperature monitoring on industrial high-temperature pipelines.Moreover,the designed self-powered wearable sensing glove can realize precise wide-range temperature detection,high-temperature warning and accurate recognition of human hand gestures.The aerogel-based intelligent wearable sensing system developed for firefighters demonstrates the desired self-powered and highly sensitive high-temperature fire warning capability.Benefitting from these desirable properties,the elastic and high-temperature-resistant aerogels present various promising applications including self-powered high-temperature monitoring,industrial overheat warning,waste heat energy recycling and even wearable healthcare.

Synergistic effect of Zr and Mo on precipitation and high-temperature properties of Al-Si-Cu-Mg alloys

This study focuses on finding a solution to the sharp decline in mechanical properties of Al-Si-Cu-Mg alloys due to rapid coarsening of traditional intermediate phases at high temperature.A new type of modified al oy,to be used in automobile engines at high temperatures,was prepared by adding Zr and Mo into Al-Si-Cu-Mg alloy.The synergistic effects of Zr and Mo on the microstructure evolution and high-temperature mechanical properties were studied.Results show that the addition of Zr and Mo generates a series of intermetallic phases dispersed in the alloy.They can improve the strength of the alloy by hindering dislocation movement and crack propagation.In addition,some nano-strengthened phases show coherent interfaces with the matrix and improve grain refinement.The addition of Mo greatly improves the heat resistance of the alloy.The extremely low diffusivity of Mo enables it to improve the thermal stability of the intermetallic phases,inhibit precipitation during aging,reduce the size of the precipitates,and improve the heat resistance of the alloy.

HZSM-5 zeolites undergoing the high-temperature process for boosting the bimolecular reaction in n-heptane catalytic cracking

High-temperature treatment is key to the preparation of zeolite catalysts.Herein,the effects of hightemperature treatment on the property and performance of HZSM-5 zeolites were studied in this work.X-Ray diffraction,N2physisorption,27Al magic angle spinning nuclear magnetic resonance(MAS NMR),and temperature-programmed desorption of ammonia results indicated that the hightemperature treatment at 650℃ hardly affected the inherent crystal and texture of HZSM-5zeolites but facilitated the conversion of framework Al to extra-framework Al,reducing the acid site and enhancing the acid strength.Moreover,the high-temperature treatment improved the performance of HZSM-5 zeolites in n-heptane catalytic cracking,promoting the conversion and light olefins yield while inhibiting coke formation.Based on the kinetic and mechanism analysis,the improvement of HZSM-5 performance caused by high-temperature treatment has been attributed to the formation of extra-framework Al,which enhanced the acid strength,facilitated the bimolecular reaction,and promoted the entropy change to overcome a higher energy barrier in n-heptane catalytic cracking.

Novel Method for Evaluating the Aging of Aviation Turbine Engine Oils via High-Temperature Bearing Deposit Tests

Aviation turbine engine oils require excellent thermal-oxidative stability because of their high-temperature environments.High-temperature bearing deposit testing is a mandatory method for measuring the thermal-oxidative performance of aviation lubricant oils,and the relevant apparatus was improved in the present study.Two different commercial aviation turbine engine oils were tested,one with standard performance(known as the SL oil)and the other with high thermal stability,and their thermal-oxidative stability characteristics were evaluated.After 100 h of high-temperature bearing testing,the SL oil was analyzed by using various analytical techniques to investigate its thermal-oxidative process in the bearing test,with its thermal-oxidative degradation mechanism also being discussed.The results indicate that the developed high-temperature bearing apparatus easily meets the test requirements of method 3410.1 in standard FED-STD-791D.The viscosity and total acid number(TAN)of the SL oil increased with the bearing test time,and various deposits were produced in the bearing test,with the micro-particles of the carbon deposits being sphere-like,rod-like,and sheet-like in appearance.The antioxidant additives in the oil were consumed very rapidly in the first 30 h of the bearing test,with N-phenyl-1-naphthylamine being consumed faster than dioctyldiphenylamine.Overall,the oil thermal-oxidative process involves very complex physical and chemical mechanisms.

High-performance and robust high-temperature polymer electrolyte membranes with moderate microphase separation by implementation of terphenyl-based polymers

Acid loss and plasticization of phosphoric acid(PA)-doped high-temperature polymer electrolyte membranes(HT-PEMs)are critical limitations to their practical application in fuel cells.To overcome these barriers,poly(terphenyl piperidinium)s constructed from the m-and p-isomers of terphenyl were synthesized to regulate the microstructure of the membrane.Highly rigid p-terphenyl units prompt the formation of moderate PA aggregates,where the ion-pair interaction between piperidinium and biphosphate is reinforced,leading to a reduction in the plasticizing effect.As a result,there are trade-offs between the proton conductivity,mechanical strength,and PA retention of the membranes with varied m/p-isomer ratios.The designed PA-doped PTP-20m membrane exhibits superior ionic conductivity,good mechanical strength,and excellent PA retention over a wide range of temperature(80–160°C)as well as satisfactory resistance to harsh accelerated aging tests.As a result,the membrane presents a desirable combination of performance(1.462 W cm^(-2) under the H_(2)/O_(2)condition,which is 1.5 times higher than that of PBI-based membrane)and durability(300 h at 160°C and 0.2 A cm^(-2))in the fuel cell.The results of this study provide new insights that will guide molecular design from the perspective of microstructure to improve the performance and robustness of HT-PEMs.

Integrated multi-scale approach combining global homogenization and local refinement for multi-field analysis of high-temperature superconducting composite magnets

Second-generation high-temperature superconducting(HTS)conductors,specifically rare earth-barium-copper-oxide(REBCO)coated conductor(CC)tapes,are promising candidates for high-energy and high-field superconducting applications.With respect to epoxy-impregnated REBCO composite magnets that comprise multilayer components,the thermomechanical characteristics of each component differ considerably under extremely low temperatures and strong electromagnetic fields.Traditional numerical models include homogenized orthotropic models,which simplify overall field calculation but miss detailed multi-physics aspects,and full refinement(FR)ones that are thorough but computationally demanding.Herein,we propose an extended multi-scale approach for analyzing the multi-field characteristics of an epoxy-impregnated composite magnet assembled by HTS pancake coils.This approach combines a global homogenization(GH)scheme based on the homogenized electromagnetic T-A model,a method for solving Maxwell's equations for superconducting materials based on the current vector potential T and the magnetic field vector potential A,and a homogenized orthotropic thermoelastic model to assess the electromagnetic and thermoelastic properties at the macroscopic scale.We then identify“dangerous regions”at the macroscopic scale and obtain finer details using a local refinement(LR)scheme to capture the responses of each component material in the HTS composite tapes at the mesoscopic scale.The results of the present GH-LR multi-scale approach agree well with those of the FR scheme and the experimental data in the literature,indicating that the present approach is accurate and efficient.The proposed GH-LR multi-scale approach can serve as a valuable tool for evaluating the risk of failure in large-scale HTS composite magnets.

基于STEAM理念联合PBL教学法在急诊医学教学中的应用研究

目的分析基于STEAM[S(science),T(technology),E(engineering),A(art),M(mathematics)]理念联合以问题为基础的教学法(problem base learning,PBL)在急诊医学教学中应用效果。方法选择2021年6月—2022年6月滨州医学院急诊科80名本临床医学专业实习生为研究对象,将其随机分为对照组、试验组,各40名。对照组接受传统教学,试验组接受基于STEAM理念联合PBL教学法。对比2组教学前后理论知识及实践操作考试成绩、实习生对教学的满意度、学习依从度及教学前后实习生职业特质评分。结果教学前,2组考核成绩对比,差异无统计学意义(P>0.05);教学3个月后,2组基础理论、实践操作考核成绩均明显提升,但试验组提升幅度更大,差异有统计学意义(P<0.001)。试验组实习生学习依从性(97.50%)高于对照组(85.00%),差异有统计学意义(P<0.001)。试验组教学方法、学术能力、带教态度管理质量评分高于对照组,差异有统计学意义(P<0.001)。教学前,2组实习生职业特质评分对比,差异无统计学意义(P>0.05);教学3个月后,试验组评分高于对照组,差异有统计学意义(P<0.001)。结论在急诊医学教学中,基于STEAM理念联合PBL教学法有利于提升实习生的综合能力,提高理论实践成绩和学习依从性。

STEAM教育理念下的项目式教学模式建构研究

随着社会的进步和科学的快速发展,社会对于创新型人才和复合型人才的需求越来越多。为了培养出更多符合社会需要、促进社会发展的人才,本文基于STEAM教育理念对项目式教学模式进行研究,从项目式教学的过程出发,构建“项目策划-项目执行-项目反馈”的教学模式,培养学生的创新思维以及解决问题的能力,试图为项目式教学提供新思路。

STEAM教育视域下中学语文跨学科深度学习的策略研究

STEAM教育是一种基于建构主义的跨学科教育,是对时代挑战的回应。以STEAM教育理念为突破口,解决当今中学语文跨学科教学存在的目标模糊,忽视语文本位;学科叠加,缺乏有效整合;学习浅表,缺少思维深度三方面问题。在中学语文课堂中采用:把握基点,语文本位,开展专题研修;明确跨点,融通互动,进行整合探究;找准落点,合作生成,促进素养提升这三种方式,以更好的教促进更好地学,推动中学语文跨学科深度学习发生,提升学生语文核心素养,将学生培养成符合时代要求的全面发展的高素质人才。

基于STEAM教育理念的“民间传统技艺”课程教学改革与实践

随着全球化和信息化的快速发展,教育模式和教育理念也在不断更新。STEAM教育作为一种重视实践、注重真实问题解决的跨学科教育理念,正逐渐成为全球教育领域关注的焦点。我国《教育信息化“十三五”规划》明确提出了有条件的地区要积极探索STEAM教育、众创空间等新型教育模式,着力提升学生的信息素养、创新意识和创新能力。(1)在这样的大背景下,将STEAM教育理念融入“民间传统技艺”课程进行教学改革与实践,利用信息技术促进美术教育教学内容和模式的改革,不仅有助于培养学生的主动探索精神,发展学生的创新意识,提升教学质量,更能为传统文化的传承与发展注入新的活力。

“活教育”理论指导下的幼儿园STEAM课程实施研究

在“活教育”理论指导下,幼儿园实施STEAM课程过程中,通过深度开发课程内容的教育价值,将不同领域内容有机融合,不仅有助于完善幼儿园的课程体系,而且有助于提升幼儿园教育质量。基于此,文章主要对“活教育”理论与STEAM课程进行概述,解析“活教育”理论指导下幼儿园STEAM课程实施的可行性,并探索行之有效的实施策略,旨在帮助幼儿园高质量地实施STEAM课程,推动我国幼儿教育事业的发展。

面向未来不确定性的中小学STEAM学习空间设计策略研究

随着STEAM教育理念的深入传播,我国中小学STEAM学习的空间建设也日益成为重要的研究课题。面向未来社会环境与教育目标的可能变化,塑造空间功能设置复合化、空间组织形态灵活化、空间情境氛围人性化的STEAM学习空间,是提升师生核心素养的必然要求。该文以六所中小学为例,从空间界面、教学模块、非正式学习空间、学习氛围、空间序列方面归纳面向未来不确定性的灵活开放的空间策略。

基于STEAM教育理念轻化工程产学研协同育人教育模式探索——以染整工艺学(一)为例

2014年,美国国际技术与工程教育学会提出落实 STEAM 教育的“6E”教学模式,这与工科重视学科融合、工程实践的教学目标相一致。本文以轻化工程专业染整工艺学(一)课程的6E教学模式改革为例,通过在课堂教学中开发学生创新思维,课下鼓励学生参与科技创新与工程实践活动,以校企合作为桥梁,不断提高学生思想道德素质、社会实践能力以及科研探索能力,以实现产学研协同育人的目的。

基于STEAM教育理念的高职院校旅游管理专业实践教学质量标准体系的构建——以“导游业务”课程为例

先进的教学理念对教育教学工作有着重要的促进作用,因此,在教学实践中立足于先进教学理念对教学工作的组织与开展进行分析和讨论是非常必要的。文章基于STEAM教育理念,对高职院校旅游管理专业实践教学质量标准体系的构建进行了深入研究。通过整合校内外资源、建立多维度的评价体系、加强教师队伍建设等措施,可以培养素质全面的导游人才,满足行业对高素质导游的需求。

基于SDPM模型开发的以科学原理为导向的幼儿园STEAM课程

基于SDPM模型开发的以科学原理为导向的幼儿园STEAM课程的目标是帮助幼儿探寻在日常生活中可能隐藏的基础科学原理,进而构建一个STEAM课程,旨在让幼儿与教育者共同研究这些科学原理。在幼儿园STEAM课程的设计阶段,课程内容主要依托于SDPM模型,该模型覆盖了情境展示、实验探究、设计以及制作等多个方面,其目的是为了协助幼儿在实践中更加深刻地理解科学原理。本研究以SDPM模型为基础,为每一个科学原理设定了STEAM主题目标,并进一步规划了相应的活动主题。每一个模型都包含了S(1个周期),D(2个周期),P(2个周期),M(2个周期),每个不同的主题都包含7个周期。为确保课程得以高效实施,每个周期的时长设置为30~40分钟。

基于STEAM教育理念的高职“现代信息技术”课程教学实践研究

在物联网、大数据、人工智能等现代技术日新月异的背景下,企事业单位对应用型、复合型技能人才的要求越来越高。将多学科知识融会贯通,在提高学生创新创业能力的同时,解决职业教育过程中的各种难题,促进学生全面发展。文章以高职高专“现代信息技术”课程为载体,秉持STEAM教育理念,将课程思政和职业素养元素融入学科知识,提高学生综合素质,实现全方位育人。

STEAM教育视域下地方院校“互联网+”竞赛助力双创活动开展新模式探索与研究

创新创业活动是近年来地方院校的重点工作之一。本文在STEAM教育视域下,结合当今政策环境,分析了当前竞赛开展的情况和存在的问题,提出具体方案措施,展示了阶段性成果。

Seasonal Prediction of Extreme High-Temperature Days in Southwestern China Based on the Physical Precursors

Extreme high temperatures frequently occur in southwestern China,significantly impacting the local ecological system and economic development.However,accurate prediction of extreme high-temperature days(EHDs)in this region is still an unresolved challenge.Based on the spatiotemporal characteristics of EHDs over China,a domain-averaged EHD index over southwestern China(SWC-EHDs)during April-May is defined.The simultaneous dynamic and thermodynamic fields associated with the increased SWC-EHDs are a local upper-level anticyclonic(high-pressure)anomaly and wavy geopotential height anomaly patterns over Eurasia.In tracing the origins of the lower boundary anomalies,two physically meaningful precursors are detected for SWC-EHDs.They are the tripolar SST change tendency from December-January to February-March in the northern Atlantic and the February-March mean snow depth in central Asia.Using these two selected predictors,a physics-based empirical model prediction was applied to the training period of 1961–2005 to obtain a skillful prediction of the EHDs index,attaining a correlation coefficient of 0.76 in the independent prediction period(2006–19),suggesting that 58%of the total SWC-EHDs variability is predictable.This study provides an estimate for the lower bound of the seasonal predictability of EHDs as well as for the hydrological drought over southwestern China.

Research on the impact of high-temperature aging on the thermal safety of lithium-ion batteries

Understanding the thermal safety evolution of lithium-ion batteries during high-temperature usage conditions bears significant implications for enhancing the safety management of aging batteries.This work investigates the thermal safety evolution mechanism of lithium-ion batteries during high-temperature aging.Similarities arise in the thermal safety evolution and degradation mechanisms for lithium-ion batteries undergoing cyclic aging and calendar aging.Employing multi-angle characterization analysis,the intricate mechanism governing the thermal safety evolution of lithium-ion batteries during high-temperature aging is clarified.Specifically,lithium plating serves as the pivotal factor contributing to the reduction in the self-heating initial temperature.Additionally,the crystal structure of the cathode induced by the dissolution of transition metals and the reductive gas generated during aging attacking the crystal structure of the cathode lead to a decrease in thermal runaway triggering temperature.Furthermore,the loss of active materials and active lithium during aging contributes to a decline in both the maximum temperature and the maximum temperature rise rate,ultimately indicating a decrease in the thermal hazards of aging batteries.

Study on the effect of thermal deformation on the liquid seal of high-temperature molten salt pump in molten salt reactor

The high-temperature molten salt pump is the core equipment in a molten salt reactor that drives the flow of the molten salt coolant.Rotor stability is key to the continuous and reliable operation of the molten salt pump,and the liquid seal at the wear ring can affect the dynamic characteristics of the rotor system.When the molten salt pump is operated in the hightemperature molten salt medium,thermal deformation of the submerged parts inevitably occurs,changing clearance between the stator and rotor,affecting the leakage and dynamic characteristics of the seal.In this study,the seal leakage,seal dynamic characteristics,and rotor system dynamic characteristics are simulated and analyzed using finite element simulation software based on two cases of considering the effect of seal thermal deformation effect or not.The results show a significant difference in the leakage characteristics and dynamic characteristics of the seal obtained by considering the effect of seal thermal deformation and neglecting the effect of thermal deformation.The leakage flow rate decreases,and the first-order critical speed of the seal-bearing-rotor system decrease after considering the seal’s thermal deformation.