high temperature

高温
  • 文章类型: Journal Article
    尽管WRKY转录因子在植物对高温胁迫的反应中起着至关重要的作用,对IIb组WRKY家族成员知之甚少。这里,我们从白芍中鉴定出WRKY-IIb蛋白PlWRKY47。),它充当核定位的转录激活因子。PlWRKY47的表达水平与高温耐受性呈正相关。PlWRKY47在乳酸丙菌中的沉默通过积累活性氧(ROS)导致对高温胁迫的耐受性降低。PlWRKY47的过表达通过减少ROS积累来提高植物的耐高温性。此外,PlWRKY47直接与胞浆甘油醛-3-磷酸脱氢酶2(PlGAPC2)基因的启动子结合并激活其转录。PlGAPC2还通过增加NAD含量来抑制ROS的产生,从而正向调节紫草的高温耐受性。此外,PlWRKY47与自身物理相互作用形成同源二聚体,和PlWRKY47也可以与一个IIb组WRKY家族成员PlWRKY72相互作用形成异二聚体,它们都促进PlWRKY47结合并激活PlGAPC2。这些数据支持PlWRKY47-PlWRKY47同二聚体和PlWRKY72-PlWRKY47异二聚体可以直接激活PlGAPC2表达,通过抑制丙交酯中的ROS生成来提高高温耐受性。这些结果将为WRKY-IIb转录因子对植物高温胁迫反应提供重要的见解。
    Although WRKY transcription factors play crucial roles in plant responses to high-temperature stress, little is known about Group IIb WRKY family members. Here, we identified the WRKY-IIb protein PlWRKY47 from herbaceous peony (Paeonia lactiflora Pall.), which functioned as a nuclear-localized transcriptional activator. The expression level of PlWRKY47 was positively correlated with high-temperature tolerance. Silencing of PlWRKY47 in P. lactiflora resulted in the decreased tolerance to high-temperature stress by accumulating reactive oxygen species (ROS). Overexpression of PlWRKY47 improved plant high-temperature tolerance through decreasing ROS accumulation. Moreover, PlWRKY47 directly bound to the promoter of cytosolic glyceraldehyde-3-phosphate dehydrogenase 2 (PlGAPC2) gene and activated its transcription. PlGAPC2 was also positively regulated high-temperature tolerance in P. lactiflora by increasing NAD+ content to inhibit ROS generation. Additionally, PlWRKY47 physically interacted with itself to form a homodimer, and PlWRKY47 could also interact with one Group IIb WRKY family member PlWRKY72 to form a heterodimer, they all promoted PlWRKY47 to bind to and activate PlGAPC2. These data support that the PlWRKY47-PlWRKY47 homodimer and PlWRKY72-PlWRKY47 heterodimer can directly activate PlGAPC2 expression to improve high-temperature tolerance by inhibiting ROS generation in P. lactiflora. These results will provide important insights into the plant high-temperature stress response by WRKY-IIb transcription factors.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    深层高温油气藏的开发导致储层温度随着油藏深度的增加而升高,从而对压裂液的耐热性提出了更高的要求。瓜尔胶压裂液难以承受超过160°C的温度,因此要求开发相应的交联剂,温度稳定剂,和其他添加剂来增强压裂系统的热稳定性。考虑到深层和超深层储层的独特特征,如极端埋葬深度(超过6000米),超高温(高于160°C),和高压裂压力,对瓜尔胶压裂液体系进行了实验改造,专门为超高温量身定做。实验确定并选择了超高温压裂液的单个试剂,包括交联剂,热稳定剂,返排辅助工具,和粘土抑制剂。通过严格的实验,这些超高温压裂液系统的关键制剂已经成功开发,包括最佳增稠剂GBA1-2、交联剂BA1-1、抗溶胀剂FB-1和破胶剂TS-1。不同添加剂剂量的评估促进了最佳瓜尔胶压裂液系统的开发,它具有出色的耐高温性能,同时最大限度地减少损坏和摩擦。我们的实验结果表明,即使在我们的超高温压裂液在180°C下以170s-1剪切2小时后,其粘度保持在200mPas以上,这是其耐高温性能优异的明显证明。这一成就标志着在为超深层和超高温储层的改造和增产提供合适的压裂液系统方面取得了实质性进展,也为今后相关领域的进一步探索和应用奠定了坚实的基础。
    The development of deep high-temperature oil and gas reservoirs gives rise to a rise in reservoir temperature along with the depth of the oil reservoir, thereby imposing higher requirements on the heat resistance of fracturing fluid. Guar gum fracturing fluid has difficulty tolerating temperatures exceeding 160 °C, thereby demanding the development of corresponding cross-linking agents, temperature stabilizers, and other additives to enhance the thermal stability of the fracturing system. Considering the distinctive characteristics of deep and ultra-deep reservoirs, such as extreme burial depth (exceeding 6000 m), ultra-high temperature (higher than 160 °C), and high fracturing pressure, an experimental modification of a guar gum fracturing fluid system was carried out, specifically tailored for ultra-high temperatures. The experiment identified and selected individual agents for ultra-high temperature fracturing fluids, including crosslinking agents, thermal stabilizers, flowback aids, and clay inhibitors. Through rigorous experimentation, these key agents for an ultra-high temperature fracturing fluid system have been successfully developed, including the optimal thickener GBA1-2, crosslinking agent BA1-1, anti-swelling agent FB-1, and gel breaker TS-1. The evaluation of diverse additive dosages has facilitated the development of an optimal guar fracturing fluid system, which exhibits outstanding high-temperature resistance while minimizing damage and friction. The outcomes of our experiments indicate that even after subjecting our ultra-high temperature fracturing fluid to 2 h of shearing at 170 s-1 at 180 °C, its viscosity remained above 200 mPa s-a distinct proof of its superior performance in withstanding high temperatures. This achievement represents a substantial progress in providing a suitable fracturing fluid system for the transformation and stimulation of ultra-deep and ultra-high temperature reservoirs, and also lays a solid foundation for further exploration and application in related fields in the future.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    亚洲蜜蜂(Apiscerana)作为传粉媒介为生态稳定服务起着至关重要的作用。然而,它们的增殖和生长受到环境温度胁迫的显著影响。这项研究探讨了Apiscerana囊泡抑制性氨基酸转运蛋白基因(AcVIAAT)在保护亚洲蜜蜂免受高温胁迫中的功能。通过触发与氧化应激相关的基因,AcVIAAT基因在经受不同热条件的蜜蜂中表现出阳性反应。分子对接,免疫共沉淀,和ELISA验证AcVIAAT蛋白与γ-氨基丁酸(GABA)相互作用的能力,一个关键的抑制性神经递质.对蜜蜂施用GABA可显着提高其在高温胁迫下的存活率,同时也上调了与氧化应激相关的基因。因此,这些发现表明,AcVIAAT基因通过促进GABA转运来调节氧化应激相关基因,从而增强蜜蜂的体温调节能力。分布在北部和南部地区的A.cerana种群中AcVIAAT基因中六个非同义SNP的表征表明基因变异与环境适应性之间存在潜在关联。我们的研究结果有助于阐明亚洲蜜蜂高温耐受性的分子机制,并为通过遗传改良增强耐热性提供了有希望的遗传标记。
    Asian honeybees (Apis cerana) play a crucial role as pollinators to service for the ecological stability. However, their proliferation and growth are significantly impacted by environmental temperature stress. This study delves into the function of the Apis cerana vesicular inhibitory amino acid transporter gene (AcVIAAT) in safeguarding Asian honeybees against high-temperature stress. The AcVIAAT gene exhibits positive responsiveness in honeybees subjected to varying thermal conditions by triggering the genes associated with oxidative stress. Molecular docking, co-immunoprecipitation, and ELISA verify the capacity of the AcVIAAT protein to interact with γ-aminobutyric acid (GABA), a key inhibitory neurotransmitter. Administering GABA to honeybees significantly improves their survival rate under high-temperature stress and also simultaneously upregulating oxidative stress-related genes. Therefore, these findings reveal that the AcVIAAT gene enhances the thermoregulatory capacity of honeybees by modulating oxidative stress-related genes through facilitating GABA transport. The characterization of six non-synonymous SNPs in the AcVIAAT gene among A.cerana populations distributed across both the northern and southern regions indicates a potential association between gene variation and environmental adaptation. Our results contribute to elucidating the molecular mechanisms underlying high-temperature tolerance in Asian honeybees and provide a promising genetic marker for enhancing heat tolerance through genetic improvement.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    为研究高温和碳纤维钢筋对混凝土材料动态力学性能的影响,马弗炉被用来处理两种标本,普通和碳纤维钢筋混凝土,在25、200、400和600°C的高温下。使用霍普金森压杆(SHPB)测试装置结合高速摄像装置,对高温暴露后的两个试样进行冲击压缩试验,观察试样的裂纹扩展过程。高温和碳纤维增强对峰值应力的影响,能量耗散密度,分析了混凝土的裂纹扩展和分形维数。结果表明,在25、200、400和600°C下,素混凝土试件的相应峰值强度分别为88.37、93.21、68.85和54.90MPa,分别,高温暴露后的峰强度先略有增加,然后迅速下降。在25、200、400和600°C高温作用后,对应于碳纤维钢筋混凝土试样的平均峰值强度是普通混凝土的1.13、1.13、1.21和1.19倍,分别,平均破碎能耗密度为普通混凝土的1.27、1.31、1.73和1.59倍,分别。碳纤维钢筋的加入显著增强了混凝土结构的抗冲击能力和耗能能力,温度越高,增长越显著。温度升高会增加裂纹扩展的数量和宽度,碳纤维钢筋的高抗拉强度和与混凝土材料的协同作用降低了试件的裂纹扩展程度。混凝土的分形维数在1.92至2.68之间,碳纤维钢筋混凝土试样的分形维数在1.61至2.42之间,在25、200、400和600°C下高温作用后,素混凝土试样的相应分形维数的平均值分别是纤维增强混凝土试样的1.19、1.21、1.10和1.11倍,分别。碳纤维筋的掺入降低了混凝土在冲击荷载作用下的破裂和破碎程度,提高了混凝土结构的安全性和稳定性。
    To investigate the effects of high temperature and carbon fiber-bar reinforcement on the dynamic mechanical properties of concrete materials, a muffle furnace was used to treat two kinds of specimens, plain and carbon fiber-bar reinforced concrete, at high temperatures of 25, 200, 400 and 600 °C. Impact compression tests were carried out on two specimens after high-temperature exposure using a Hopkinson pressure bar (SHPB) test setup combined with a high-speed camera device to observe the crack extension process of the specimens. The effects of high temperature and carbon fiber-bar reinforcement on the peak stress, energy dissipation density, crack propagation and fractal dimension of the concrete were analyzed. The results showed that the corresponding peak strengths of the plain concrete specimens at 25, 200, 400, and 600 °C were 88.37, 93.21, 68.85, and 54.90 MPa, respectively, and the peak strengths after the high-temperature exposure first increased slightly and then decreased rapidly. The mean peak strengths corresponding to the carbon fiber-bar reinforced concrete specimens after high-temperature action at 25, 200, 400, and 600 °C are 1.13, 1.13, 1.21, and 1.19 times that of plain concrete, respectively, and the mean crushing energy consumption densities are 1.27, 1.31, 1.73, and 1.59 times that of plain concrete, respectively. The addition of carbon fiber-bar reinforcement significantly enhanced the impact resistance and energy dissipation of the concrete structure, and the higher the temperature was, the more significant the increase. An increase in temperature increases the number of crack extensions and width, and the high tensile strength of the carbon fiber-bar reinforcement and the synergistic effect with the concrete material reduce the degree of crack extension in the specimen. The fractal dimension of the concrete ranged from 1.92 to 2.68, that of the carbon fiber-bar reinforced concrete specimens ranged from 1.61 to 2.42, and the mean values of the corresponding fractal dimensions of the plain concrete specimens after high-temperature effects at 25, 200, 400, and 600 °C were 1.19, 1.21, 1.10, and 1.11 times those of the fiber-reinforced concrete specimens, respectively. The incorporation of carbon fiber-bar reinforcement reduces the degree of rupture and fragmentation of concrete under impact loading and improves the safety and stability of concrete structures.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    全球变暖对全球粮食安全构成重大挑战,玉米作为主要作物在确保全球粮食供应方面发挥着至关重要的作用。因此,研究高温(HT)对玉米种植的影响对于解决粮食安全问题至关重要。尽管有许多研究探索了HT对玉米生长和产量的影响,由于实验环境的变化,对这些影响的全面理解仍然难以捉摸,品种,和成长阶段。为了解决这些限制,进行了荟萃分析,以评估HT对玉米产量和籽粒成分的影响,综合34项研究的575项观察数据。研究结果表明,1)HT显着降低了籽粒产量32.7-40.9%,籽粒淀粉含量降低了2.8-10.5%;2)籽粒发育阶段附近(包括蚕丝,水泡,牛奶)是玉米籽粒对HT最敏感的时期;3)HT程度与其对谷物产量的影响之间存在显着负相关(R2=0.38;P=0.043);4)HT天数和程度对玉米产量的影响同样重要。总之,本荟萃分析通过综合评价HT对产量和籽粒组分的影响,为提高玉米生产和栽培实践的抗逆性建立了理论框架。
    Global warming poses a significant challenge to global food security, with maize playing a vital role as a staple crop in ensuring food availability worldwide. Therefore, investigating the impact of high temperature (HT) on maize cultivation is imperative for addressing food security concerns. Despite numerous studies exploring the effects of HT on maize growth and yield, a comprehensive understanding of these effects remains elusive due to variations in experimental environments, varieties, and growth stages. To solve these limitations, a meta-analysis was conducted to assess the effects of HT on maize yield and grain components, synthesizing data from 575 observations across 34 studies. The findings indicate that 1) HT significantly reduced grain yield by 32.7-40.9 % and grain starch content by 2.8-10.5 %; 2) the vicinity of kernel development stage (include silking, blister, milk) is the period when maize kernels are most sensitive to HT; 3) a significant negative correlation was observed between HT degree and their impact on grain yield (R2 = 0.38, P = 0.043); and 4) the effects of HT days and degrees on maize yield were equally important. In conclusion, this meta-analysis establishes a theoretical framework for enhancing the resilience of maize production and cultivation practices by comprehensively evaluating the impact of HT on yield and grain components.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    在大规模污水处理过程中,产生大量过量的污泥,这将对环境造成严重污染。近年来,厌氧消化技术由于能更好地实现污泥减量化,厌氧消化后的产品和副产品可以充分利用资源。在这项研究中,在30℃和50℃的发酵过程中加入纤维素作为共发酵底物,以提高VFAs的产量。结果表明,在30℃和50℃条件下,纤维素均能显著提高VFAs的得率。同时,还测量了发酵过程中的COD和还原糖的产生。在类和属水平上对微生物群落结构的分析表明,与纤维素降解密切相关的几个属的比例,例如Cellvibrio,纤维杆菌,随着纤维素的添加,孢子藻和孢子藻显著增加。共发酵被认为是一种经济和环境友好的污泥和其他固体废物处理策略。分析纤维素作为底物对高温和中温下VFA生产的影响对于探索在厌氧发酵中增加VFA生产的方法非常重要。
    During large-scale sewage treatment, a large amount of excessive sludge is produced, which will cause serious pollution in the environment. In recent years, anaerobic digestion technology has been widely promoted because it can achieve better sludge reduction, and the products and byproducts after anaerobic digestion can be fully utilized as resources. In this study, cellulose was added as the co-fermentation substrate during the fermentation process at 30 ℃ and 50 ℃ to enhance the production of VFAs. The result indicated that cellulose could significantly increase the yield of VFAs in both 30 ℃ and 50 ℃. Meanwhile, COD and reducing sugar generation in the fermentation process were also measure. Analysis of the microbial community structure at the class and genus levels revealed that the proportion of several genus closely related with cellulose degradation such as Cellvibrio, Fibrobacter, and Sporocytophaga were significantly increased with the addition of cellulose. Co-fermentation was recognized as an economic and environmental friendly strategy for sludge and other solid waste treatment. The analysis of the effect of cellulose as a substrate on the production of VFAs at high and medium temperatures is highly important for exploring ways to increase the production of VFAs in anaerobic fermentation.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    由于其准确性高,出色的稳定性,小尺寸,成本低,硅压阻式压力传感器用于监测高温下的井下压力,高压条件。然而,由于硅的温度敏感性,高且变化很大的井下温度导致压力传感器的压力测量中的显著偏差。温度系数因制造商而异,甚至在同一制造商内的批次而异。为确保高温下井下压力监测的高精度和长期稳定性,本研究提出了一种基于双线性插值的井下高温高压环境下压阻式压力传感器的温度补偿方法。使用高温共校准设备进行了多次校准,以获得每个传感器的单独温度特性。通过校准,结果发现,在相同温度下,被测压力测量系统的输出与压力呈正线性关系,在相同压力下,与温度呈近似负线性关系。作为后续双线性插值温度补偿方法的偏差校正。基于这个结果,经过最小二乘拟合和插值,引入双线性插值方法来补偿温度引起的压力偏差,这更容易在微控制器(MCU)中实现。测试结果表明,该方法显著提高了被测传感器的整体测量精度,从21.2%F.S.提高到0.1%F.S.降低了单片机补偿模型的计算复杂度,满足高温高压下井下压力监测的高精度需求。
    Due to their high accuracy, excellent stability, minor size, and low cost, silicon piezoresistive pressure sensors are used to monitor downhole pressure under high-temperature, high-pressure conditions. However, due to silicon\'s temperature sensitivity, high and very varied downhole temperatures cause a significant bias in pressure measurement by the pressure sensor. The temperature coefficients differ from manufacturer to manufacturer and even vary from batch to batch within the same manufacturer. To ensure high accuracy and long-term stability for downhole pressure monitoring at high temperatures, this study proposes a temperature compensation method based on bilinear interpolation for piezoresistive pressure sensors under downhole high-temperature and high-pressure environments. A number of calibrations were performed with high-temperature co-calibration equipment to obtain the individual temperature characteristics of each sensor. Through the calibration, it was found that the output of the tested pressure measurement system is positively linear with pressure at the same temperatures and nearly negatively linear with temperature at the same pressures, which serves as the bias correction for the subsequent bilinear interpolation temperature compensation method. Based on this result, after least squares fitting and interpolating, a bilinear interpolation approach was introduced to compensate for temperature-induced pressure bias, which is easier to implement in a microcontroller (MCU). The test results show that the proposed method significantly improves the overall measurement accuracy of the tested sensor from 21.2% F.S. to 0.1% F.S. In addition, it reduces the MCU computational complexity of the compensation model, meeting the high accuracy demand for downhole pressure monitoring at high temperatures and pressures.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    碳纤维增强聚醚醚酮(CF/PEEK)复合材料广泛应用于航空航天,医疗器械,和汽车行业,以其卓越的机械性能和耐高温性而闻名。尽管有这些优势,动态载荷条件下CF/PEEK的热机械耦合行为尚不清楚。本研究旨在探讨CF/PEEK在高应变率下的热机械耦合效应。采用霍普金森杆冲击测试和扫描电子显微镜(SEM)进行详细表征。我们的发现表明,温度的升高导致屈服强度的显着降低,峰值应力,和CF/PEEK的比能量吸收,而断裂应变没有显著影响。例如,在200°C,屈服强度,峰值应力,比能量吸收下降了39%,37%,38%,分别,与它们在20°C下的值相比。此外,随着应变率的增加,屈服强度,峰值应力,比能量吸收,和断裂应变均表现出应变硬化效应。然而,随着应变率的进一步增加,4000s-1以上,应变速率对屈服强度和峰值应力的增强作用逐渐减弱。在高速冲击条件下,温度和应变率的交互作用显著影响了CF/PEEK的力学性能。虽然应变率通常增强了这些性能,随着温度的升高,应变硬化对屈服强度的影响减弱,温度和应变率都有助于增加比能量吸收。微损伤机理分析表明,纤维与基体之间的界面脱粘和滑动在静态压缩下比在动态压缩下更为明显。从而降低了应力传递的效率。此外,较高的温度导致PEEK基质软化并表现出增加的粘弹性行为,进而影响材料的韧性和应力传递机制。这些见解具有重大的工程意义,特别是CF/PEEK复合材料的优化设计和在极端环境中的应用。
    Carbon-fiber-reinforced polyetheretherketone (CF/PEEK) composites are widely utilized in aerospace, medical devices, and automotive industries, renowned for their superior mechanical properties and high-temperature resistance. Despite these advantages, the thermomechanical coupling behavior of CF/PEEK under dynamic loading conditions is not well understood. This study aims to explore the thermomechanical coupling effects of CF/PEEK at elevated strain rates, employing Hopkinson bar impact tests and scanning electron microscopy (SEM) for detailed characterization. Our findings indicate that an increase in temperature led to significant reductions in the yield strength, peak stress, and specific energy absorption of CF/PEEK, while fracture strain had no significant effect. For instance, at 200 °C, the yield strength, peak stress, and specific energy absorption decreased by 39%, 37%, and 38%, respectively, compared to their values at 20 °C. Furthermore, as the strain rate increased, the yield strength, peak stress, specific energy absorption, and fracture strain all exhibited strain-hardening effects. However, as the strain rate further increased, above 4000 s-1, the enhancing effect of the strain rate on the yield strength and peak stress gradually diminished. The interaction of the temperature and strain rate significantly affected the mechanical performance of CF/PEEK under high-speed impact conditions. While the strain rate generally enhanced these properties, the strain-hardening effect on the yield strength weakened as the temperature increased, and both the temperature and strain rate contributed to the increase in specific energy absorption. Microdamage mechanism analysis revealed that interface debonding and sliding between the fibers and the matrix were more pronounced under static compression than under dynamic compression, thereby diminishing the efficiency of stress transfer. Additionally, higher temperatures caused the PEEK matrix to soften and exhibit increased viscoelastic behavior, which in turn affected the material\'s toughness and the mechanisms of stress transfer. These insights hold substantial engineering significance, particularly for the optimization of CF/PEEK composite design and applications in extreme environments.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    高强度混凝土(HSC)具有优异的抗压强度和耐久性,使其成为各种工程应用中的热门选择。然而,在高温的影响下,HSC容易开裂,结合聚乙烯醇纤维(PVA纤维)探讨其工程应用前景。本文研究了不同加热温度和冷却技术下PVA纤维增强HSC的物理和力学特性。实验结果揭示了温度升高与样品中可观察到的变化之间的相关性:表面色调逐渐变浅,破裂的频率增加,质量损失率大幅上升,特别是在温度超过400°C之后。关于机械性能,随着加热温度的升高,动态弹性模量和压缩弯曲强度均降低。随着PVA纤维量的增加,同时保持稳定的温度,这些测量最初显示增加,然后减少。产生最佳压缩和弯曲强度的纤维含量为0.2%和0.3%,按这个顺序。考虑到冷却方式的影响,喷水冷却比自然冷却对物理机械性能的影响更大。此外,采用SEM检查HSC的微观结构,增强对其物理和机械特性变化的理解。这项研究的结果提供了有关HSC高温行为的重要信息,作为指导设计的宝贵资源,建筑,并维护包含HSC的结构。此外,这项研究将有助于推进HSC技术的进步和利用。
    High-strength concrete (HSC) boasts excellent compressive strength and durability, making it a popular choice in various engineering applications. However, under the impact of high temperatures, HSC tends to crack easily, so it is combined with polyvinyl alcohol fiber (PVA fiber) to explore its engineering application prospect. This paper investigated the physical and mechanical characteristics of HSC reinforced with PVA fibers subjected to different heating temperatures and cooling techniques. The experimental results reveal a correlation between rising temperatures and observable changes in the specimens: a progressively lighter surface hue, an augmented frequency of cracking, and a considerable escalation in the mass loss rate, particularly after the temperature exceeds 400 °C. Regarding mechanical properties, the dynamic elastic modulus and compressive and flexural strength all decrease as the heating temperature increases. As the amount of PVA fiber rises while maintaining a steady temperature, these measurements initially show an increase followed by a decrease. The fiber contents yielding the best compressive and flexural strength are 0.2% and 0.3%, in that order. Considering the influence of cooling methods, water spray cooling has a greater impact on physical and mechanical properties than natural cooling. Furthermore, SEM was employed to scrutinize the microstructure of HSC, enhancing comprehension of the alterations in its physical and mechanical characteristics. The findings of this research offer significant information regarding the high-temperature behavior of HSC, serving as a valuable resource for guiding the design, building, and upkeep of structures that incorporate HSC. Additionally, this study will aid in advancing the progress and utilization of HSC technology.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    建筑物火灾将严重威胁人类安全。硅气凝胶具有较低的导热性和热稳定性,作为阻燃材料已广泛应用于建筑防火结构中。然而,二氧化硅气凝胶的天然脆性将限制其应用。在这项工作中,通过分子动力学模拟研究了断层对二氧化硅气凝胶热稳定性的影响,模拟时间长(20ns)。此外,利用应变结构(拉伸应变为10%,20%,30%,和40%)。发现当拉伸应变小于20%时,二氧化硅骨架可以保持稳定。故障对热稳定性的影响可以忽略。二氧化硅骨架在加热过程期间热振动。然而,当拉伸应变超过30%时,观察到断层将增强二氧化硅骨架的合并。二氧化硅气凝胶在800K下可以稳定。相信这项研究的结果将为防火材料的发展铺平道路。
    Building fire will seriously threaten human safety. Silica aerogel with low thermal conductivity and thermal stability as fire-retardant material has been widely used in building fireproof structures. However, the natural fragility of silica aerogel will limit its application. In this work, the effects of faults on the thermal stability of silica aerogel are studied by molecular dynamics simulation with large simulation time (20 ns). Additionally, the atomic model of silica aerogel with random faults is built by a straining structure (tensile strains are 10%, 20%, 30%, and 40%). It is found that when the tensile strain is less than 20%, the silica backbone can remain stable. The effects of faults on the thermal stability can be neglected. The silica backbone thermally vibrates during the heating process. However, when the tensile strain is over 30%, it is observed that the faults will enhance the silica backbone merging. Silica aerogel can be stable under 800 K. It is believed that the results of this study will pave the way for the development of fireproof materials.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

公众号