Metal–Organic Gel Leading to Customized Magnetic‑Coupling Engineering in Carbon Aerogels for Excellent Radar Stealth and Thermal Insulation Performances

Metal–organic gel(MOG)derived composites are promising multi-functional materials due to their alterable composition,identifiable chemical homogeneity,tunable shape,and porous structure.Herein,stable metal–organic hydrogels are prepared by regulating the complexation effect,solution polarity and curing speed.Meanwhile,collagen peptide is used to facilitate the fabrication of a porous aerogel with excellent physical properties as well as the homogeneous dispersion of magnetic particles during calcination.Subsequently,two kinds of heterometallic magnetic coupling systems are obtained through the application of Kirkendall effect.FeCo/nitrogen-doped carbon(NC)aerogel demonstrates an ultra-strong microwave absorption of−85 dB at an ultra-low loading of 5%.After reducing the time taken by atom shifting,a FeCo/Fe3O4/NC aerogel containing virus-shaped particles is obtained,which achieves an ultra-broad absorption of 7.44 GHz at an ultra-thin thickness of 1.59 mm due to the coupling effect offered by dual-soft-magnetic particles.Furthermore,both aerogels show excellent thermal insulation property,and their outstanding radar stealth performances in J-20 aircraft are confirmed by computer simulation technology.The formation mechanism of MOG is also discussed along with the thermal insulation and electromagnetic wave absorption mechanism of the aerogels,which will enable the development and application of novel and lightweight stealth coatings.

Energy-Saving Construction Technologies for Buildings

The development of the construction industry is shifting towards low-carbon construction,so it is necessary to improve and optimize related construction concepts,methods,and processes.By improving resource and energy control efficiency in building projects,minimizing construction waste,and reducing environmental impact,a foundation for the sustainable development of the industry can be established.This paper mainly analyzes the significance of low-carbon energy-saving construction technology and the control factors of construction,summarizes the status quo of the development of building energy-saving construction,and puts forward strategies for applying building energy-saving construction technology.These strategies serve to achieve low-carbon and energy-saving goals to promote the healthy development of energy-saving construction.

Numerical and experimental evaluation for density-related thermal insulation capability of entangled porous metallic wire material

Entangled porous metallic wire material(EPMWM)has the potential as a thermal insulation material in defence and engineering.In order to optimize its thermophysical properties at the design stage,it is of great significance to reveal the thermal response mechanism of EPMWM based on its complex structural effects.In the present work,virtual manufacturing technology(VMT)was developed to restore the physics-based 3D model of EPMWM.On this basis,the transient thermal analysis is carried out to explore the contact-relevant thermal behavior of EPMWM,and then the spiral unit containing unique structural information are further extracted and counted.In particular,the thermal resistance network is numerically constructed based on the spiral unit through the thermoelectric analogy method to accurately predict the effective thermal conductivity(ETC)of EPMWM.Finally,the thermal diffusivity and specific heat of the samples were obtained by the laser thermal analyzer to calculate the ETC and thermal insulation factor of interest.The results show that the ETC of EPMWM increases with increasing temperature or reducing density under the experimental conditions.The numerical prediction is consistent with the experimental result and the average error is less than 4%.

Research on Thermal Insulation and Energy Saving of External Wall in City High-rise Building of Cold Area

This paper applies the method of numerical simulation and field detection, and studied energy-saving insulation characteristics on the external wails of high-rise buildings in cold area, analyze and recommend the best arrangement of building and the most generous exterior wall insulation system suitable for cold area, and the degree of insulation materials were studied. The results show that： the mode preferred cold area is exterior insulation, insulation material made of extruded polystyrene board, frame structure filling wall preferred ceramsite hollow block.

Scalable and flexible porous hybrid film as a thermal insulating subambient radiative cooler for energy-saving buildings

Passive daytime radiative cooling(PDRC)is one of the promising alternatives to electrical cooling and has a significant impact on worldwide energy consumption and carbon neutrality.Toward real-world applications,however,the parasitic heat input and heat leakage pose crucial challenges to commercial and residential buildings cooling.The integrating of radiative cooling and thermal insulation properties represents an attractive direction in renewable energy-efficient building envelope materials.Herein,we present a hierarchically porous hybrid film as a scalable and flexible thermal insulating subambient radiative cooler via a simple and inexpensive inverse high internal phase emulsion strategy.The as-prepared porous hybrid film exhibits an intrinsic combination of high solar reflectance(0.95),strong longwave infrared thermal emittance(0.97),and low thermal conductivity(31 mW/(m K)),yielding a subambient cooling temperature of~8.4℃ during the night and~6.5℃ during the hot midday with an average cooling power of~94 W/m^(2) under a solar intensity of~900 W/m^(2).Promisingly,combining the superhydrophobicity,durability,superelasticity,robust mechanical strength,and industrial applicability,the film is favorable for large-scale,sustainable and energy-saving applications in a wide variety of climates and complicated surfaces,enabling a substantial reduction of energy costs,greenhouse gas emission and associated ozone-depleting from traditional cooling systems.

液氢储存低温绝热技术研究进展

液氢储存具有单位体积储氢密度高、长距离输送成本低等优势。但液氢储存是将氢气冷却到-253℃进行液化后储存在绝热容器中,故对储存容器的低温绝热性能要求极高。围绕液氢储存被动绝热和主动绝热技术,通过文献调研的方式回顾了当前液氢储存低温绝热技术的研究进展,介绍了不同绝热技术的原理,比较了不同绝热技术的适用范围,分析了目前不同绝热技术中存在的瓶颈问题和不足之处,总结了各绝热技术未来的发展趋势。为液氢储存低温绝热技术的发展提供参考。

寒区隧道空气幕保温技术效果分析

为研究寒区隧道空气幕保温技术的保温效果,以某隧道为设计背景,应用相似理论和量纲分析法,首次搭建由外界环境控制装置、棚洞模型、空气幕射流控制装置和温度测试装置4部分组成的模型试验系统。试验采用控制变量法分析不同工况下空气幕保温技术的效果,研究结果表明:空气幕保温技术的最优射流角度为30°~40°;当外界温度为-10℃,外界风速为2 m/s时,一道空气幕墙可以满足隧道的防寒保温需求;空气幕射流速度应根据隧址处的自然环境变化,才能有较好的防寒效果;寒区隧道空气幕保温技术的保温原则为以加热为主、隔风为辅;当串联多道空气幕共同工作时,最佳串联间距为30 m。模型试验填补了寒区隧道空气幕保温技术试验的空白,结果可为我国寒区隧道工程建设提供思路和参考。

充气调温服装研究进展及发展趋势

充气调温服装利用气囊锁闭静止空气,从而替代传统隔热层的填充材料,具有绿色环保、自由调温、轻量便携等特点,在防寒服领域极具应用价值。该文介绍了国内外充气调温服装的产品与专利技术,分析了充气调温服装的调温机理,总结了目前国内外学者对充气调温服装保暖性影响因素的研究现状,并提出充气调温服装的不足与未来发展趋势。

组合砌体墙损伤红外热像检测方法研究

轻钢芯柱-保温夹层组合砌体墙的裸露部分受自然因素影响易出现墙体损伤,影响墙体的使用寿命,为此提出组合砌体墙损伤红外热像检测方法。该方法通过超声红外热成像技术,获取组合砌体墙损伤的红外图像,基于双边滤波方法,提升了组合砌体墙损伤图像的低照度;基于图像处理技术和形态学检测技术,对组合砌体墙损伤边缘进行精准提取,确定损伤程度,实现精确检测。结果表明:当图像数量为20~100张时,该方法检测的mAP值与召回率均高于90.00%,墙体损伤检测较为完整且损伤支线明显,直观表现了检测效果;准确度均高于95.00%,提升了墙体损伤检测方法的检测完整度;平均IoU均高于85.00%,有效提高了损伤区域与标定区域之间的重叠率。该方法的检测效果好、性能高。

建筑施工中建筑外墙保温节能技术分析

为适应新时期建筑工程的发展需求,实现节能降耗目标,文章以某建筑施工工程为例,阐述建筑施工中常用的外墙保温节能技术类型及内涵,从节能设计、保温施工和性能检验三方面分析外墙保温节能技术的具体应用,可对建筑外墙的质量提升和节能减耗起到切实作用,为建筑行业的发展提供支持。

被动式建筑节能技术要点分析

被动式节能建筑能够最大限度地降低建筑的热损失,在为人们提供舒适的居住环境的同时,能减少采暖及制冷产生的能量消耗。文章以马厂安置区幼儿园建设项目为例,先介绍了被动式建筑的主要优势,然后从新风系统、保温系统、门窗系统、辐射采暖制冷技术、气密性施工等方面阐述了被动式建筑节能施工技术,以期为同类工程提供参考。

装配式技术在老旧小区更新改造中的应用

我国城市化进程的不断加快使得老旧小区的更新改造逐渐成为城市发展的重要任务之一,然而在更新改造的进程中,传统的改建方式耗时费力的同时,也对居民的生活造成了不可避免的影响。因此,装配式技术成为了一种适配老旧小区改造更新的施工方式之一。拟以合肥市公园新村住宅小区为例,针对老旧小区山墙面设计装配式绿植种植装置——“城市绿肺”,将装配式技术应用于外围护结构改造升级,希望能起到有效缩短工期、减少污染、改善生活的作用。

隧道防水减震隔热一体化关键技术研究

西部地区交通隧道建设面临全球最为复杂的工程地质条件。受高烈度地震带、富水环境与高低温带等不良地质影响,隧道震害、水害与冻热害问题突出,隧道防水减震隔热一体化技术研究需求迫切。为此,针对多致灾因素下的交通隧道安全建养问题开展系统研究。首先,在前期研发的新型韧性非水反应高聚物材料基础上,进行隧道防水阻渗、减震隔震与保温隔热相关技术研究,开展抗渗试验、减震试验和导热系数测定试验及仿真分析。研究表明,0.6 g/cm^(3)的高聚物材料抗渗等级达到10级,具有良好的防水性能;采用外包高聚物隔震层的隧道复合衬砌结构可减少36%地震波作用下的隧道变形;温度较低时,高聚物导热系数随密度增大而呈现增大趋势,密度每增加1 g/cm^(3),导热系数增大0.1709 W/(m·K),温度较高时,高聚物导热系数随密度增大而呈现先增大后减小趋势;进一步提出隧道“围岩-初衬-高聚物-二衬”复合式衬砌支护体系。最后,开展隧道高聚物防水减震隔热层喷涂施工物理模型试验与现场技术示范,给出最佳喷涂工艺参数,实现隧道防水-减震-隔热功能的一体化应用。相关研究成果可为高烈度、富水环境及高低温带交通隧道安全设计与施工提供借鉴。

直立锁边金属屋面与复杂钢网架施工研究

以某滑雪场为研究对象,阐述钢网架施工流程及金属铝镁锰板屋面的构造节点、主要施工工艺流程及注意事项。对滑雪场屋面系统中防水和保温的节点做了施工深化,保证了保温聚氨酯的连续性、TPO柔性防水层及附加防水层的完整性,为同类型钢网架项目的施工提供了一定的参考。

建筑物外墙外保温材料的选择及施工技术分析研究

本文以外墙外保温材料为基础,主要研究了外墙外保温技术及外墙外保温隔热材料。分析了外墙外保温材料的品种及特征,剖析对比了外墙外保温材料,总结出了最方便被人们所运用的材料和技术并指出了其缺点,重点分析了常见的外墙外保温施工技术,提出了外墙外保温施工质量控制,为建筑外墙保温节能事业提出有用的技术支持。

建筑外墙保温系统的研究分析

提升建筑保温性能,降低建筑能耗是建筑节能的重要表现,建筑外墙保温作为建筑节能的重要组成部分,对建筑的整体性能有着至关重要的影响。本文阐述了外墙外保温技术、外墙内保温技术、外墙夹芯保温技术、外墙自保温技术和装配式自保温双墙复合系统等几种建筑外墙保温技术的特点,分析了外墙中保温材料以及墙体中连接件对外墙保温性能的影响。

装饰一体化装配式隔墙在高高原地区的应用

装饰一体化装配式隔墙因工效较高、质量可控、不受气候制约、节能环保,在全国大部分地区有所应用。以西藏日喀则定日机场项目为案例,通过研发新型轻钢龙骨装饰一体化装配式隔墙,利用装配式施工、干挂装饰面的工艺,解决了极端严寒地区无法湿作业的难题,同时降低了人工消耗,优化了装饰一体化隔墙的隔声、保温、耐火等性能,实现了装饰一体化装配式隔墙在高高原地区的首次应用,取得较好的效果,可为今后类似项目提供参考。

房屋建筑内外墙保温节能效益分析

简要介绍了房屋建筑内外保温层常用的材料,选择位于西北寒冷地区的3间房屋,对其在无保温层、在墙面外部安装EPS保温层、在墙面内部安装EPS保温层3种情况下的耗能和施工费用进行了比较评价。通过试验对比分析发现,安装保温层的房屋冬季保暖耗能比没有安装保温层降低了50%左右,并且墙体内保温层比外保温的耗能降低了10%左右。

外保温复合装饰线产品及施工质量控制研究

外保温复合装饰线是由机械加工的模塑聚苯乙烯泡沫塑料(EPS)、石墨改性聚苯等保温材料、耐碱玻璃纤维网格布和抹面胶浆预制而成的装饰制品,在节能建筑外墙外保温系统中广泛使用。实际工程中,外保温复合装饰线种类繁杂,构型多变,存在产品质量隐患和施工质量安全隐患。本文通过对外保温复合装饰线的产品质量和施工质量技术研究,为该类产品提供产品及施工质量控制建议,有效提高建筑外保温系统施工质量。

岩棉板外墙保温施工技术及质量控制要点

在建筑的施工过程中,应用外墙保温的施工工艺能够巩固和改善建筑本身的隔热作用,在目前的建筑施工中,随着岩棉板外保温技术的不断发展,岩棉板外保温技术的应用日益广泛。本文从建筑外保温工程的技术水平出发,进行了建筑外保温工程的岩棉板技术水平、关于操作的必要性等问题的探讨,合理地整合有关的施工技术等,并对外墙保温施工质量控制的主要内容进行了阐述。加强对外墙保温施工的质量与效果,希望通过分析能对我国建筑外保温工程进行有益的探索。