Selection and thermal physical characteristics analysis of in-situ condition preserved coring lunar rock simulant in extreme environment

With the increasing scarcity of Earth’s resources and the development of space science and technology,the exploration, development, and utilization of deep space-specific material resources(minerals, water ice, volatile compounds, etc.) are not only important to supplement the resources and reserves on Earth but also provide a material foundation for establishing extraterrestrial research bases. To achieve large depth in-situ condition-preserved coring(ICP-Coring) in the extreme lunar environment, first, lunar rock simulant was selected(SZU-1), which has a material composition, element distribution, and physical and mechanical properties that are approximately equivalent to those of lunar mare basalt. Second, the influence of the lunar-based in-situ environment on the phase, microstructure, and thermal physical properties(specific heat capacity, thermal conductivity, thermal diffusivity, and thermal expansion coefficient)of SZU-1 was explored and compared with the measured lunar rock data. It was found that in an air atmosphere, low temperature has a more pronounced effect on the relative content of olivine than other temperatures, while in a vacuum atmosphere, the relative contents of olivine and anorthite are significantly affected only at temperatures of approximately-20 and 200 ℃. When the vacuum level is less than100 Pa, the contribution of air conduction can be almost neglected, whereas it becomes dominant above this threshold. Additionally, as the testing temperature increases, the surface of SZU-1 exhibits increased microcracking, fracture opening, and unevenness, while the specific heat capacity, thermal conductivity,and thermal expansion coefficient show nonlinear increases. Conversely, the thermal diffusivity exhibits a nonlinear decreasing trend. The relationship between thermal conductivity, thermal diffusivity, and temperature can be effectively described by an exponential function(R^(2)>0.98). The research results are consistent with previous studies on real lunar rocks. These research findings are expected to be applied in the development of the test and analysis systems of ICP-Coring in a lunar environment and the exploration of the mechanism of machine-rock interaction in the in-situ drilling and coring process.

Spatiotemporal variation of ecological environment quality and extreme climate drivers on the Qinghai-Tibetan Plateau

Protecting the ecological security of the Qinghai-Tibet Plateau(QTP)is of great importance for global ecology and climate.Over the past few decades,climate extremes have posed a significant challenge to the ecological environment of the QTP.However,there are few studies that explored the effects of climate extremes on ecological environment quality of the QTP,and few researchers have made quantitative analysis.Hereby,this paper proposed the Ecological Environmental Quality Index(EEQI)for analyzing the spatial and temporal variation of ecological environment quality on the QTP from 2000 to 2020,and explored the effects of climate extremes on EEQI based on Geographically and Temporally Weighted Regression(GTWR)model.The results showed that the ecological environment quality in QTP was poor in the west,but good in the east.Between 2000 and 2020,the area of EEQI variation was large(34.61%of the total area),but the intensity of EEQI variation was relatively low and occurred mainly by a slightly increasing level(EEQI change range of 0.05-0.1).The overall ecological environment quality of the QTP exhibited spatial and temporal fluctuations,which may be attributed to climate extremes.Significant spatial heterogeneity was observed in the effects of the climate extremes on ecological environment quality.Specifically,the effects of daily temperature range(DTR),number of frost days(FD0),maximum 5-day precipitation(RX5day),and moderate precipitation days(R10)on ecological environment quality were positive in most regions.Furthermore,there were significant temporal differences in the effects of consecutive dry days(CDD),consecutive wet days(CWD),R10,and FD0 on ecological environment quality.These differences may be attributed to variances in ecological environment quality,climate extremes,and vegetation types across different regions.In conclusion,the impact of climate extremes on ecological environment quality exhibits complex patterns.These findings will assist managers in identifying changes in the ecological environment quality of the QTP and addressing the effects of climate extremes.

Will high-entropy carbides and borides be enabling materials for extreme environments?

The concept of multi-principal component has created promising opportunities for the development of novel high-entropy ceramics for extreme environments encountered in advanced turbine engines, nuclear reactors, and hypersonic vehicles, as it expands the compositional space of ceramic materials with tailored properties within a single-phase solid solution. The unique physical properties of some high-entropy carbides and borides, such as higher hardness, high-temperature strength, lower thermal conductivity, and improved irradiation resistance than the constitute ceramics, have been observed. These promising properties may be attributed to the compositional complexity, atomic-level disorder, lattice distortion, and other fundamental processes related to defect formation and phonon scattering.This manuscript serves as a critical review of the recent progress in high-entropy carbides and borides, focusing on synthesis and evaluations of their performance in extreme high-temperature, irradiation, and gaseous environments.

Stress verification of a TLP under extreme wave environment

Stress response of a tension leg platform （TLP） in extreme environments was investigated in this paper. A location on one of the gussets was selected as the object point, where directional stresses were numerically simulated and also experimentally verified by a strain gage. Environmental loading and the platform＇s structural strength were analyzed in accordance with industrial standards, utilizing linear wave theory and the finite element method （FEM）. The fast Fourier transform technique was used to calculate the stress response amplitude operators （RAO） from the records of measurements. A comparison was performed between the stress RAO of the numerical simulation and that of the actual measurements. The results indicated that the stress RAO of the numerical simulation fitted well with measured data at specified wave headings with different periods.

Femtosecond laser fabrication of nanograting-based distributed fiber sensors for extreme environmental applications

The femtosecond laser has emerged as a powerful tool for micro-and nanoscale device fabrication. Through nonlinear ionization processes, nanometer-sized material modifications can be inscribed in transparent materials for device fabrication. This paper describes femtosecond precision inscription of nanograting in silica fiber cores to form both distributed and point fiber sensors for sensing applications in extreme environmental conditions. Through the use of scanning electron microscope imaging and laser processing optimization,high-temperature stable, Type II femtosecond laser modifications were continuously inscribed,point by point, with only an insertion loss at 1 d B m~(-1) or 0.001 d B per point sensor device.High-temperature performance of fiber sensors was tested at 1000℃, which showed a temperature fluctuation of ±5.5℃ over 5 days. The low laser-induced insertion loss in optical fibers enabled the fabrication of a 1.4 m, radiation-resilient distributed fiber sensor. The in-pile testing of the distributed fiber sensor further showed that fiber sensors can execute stable and distributed temperature measurements in extreme radiation environments. Overall, this paper demonstrates that femtosecond-laser-fabricated fiber sensors are suitable measurement devices for applications in extreme environments.

Extreme Enrichment of Tellurium in Deep-Sea Sediments

Tellurium is a sort of scattered rare element on the earth. Its concentration is very low in earth＇s crust, only 1.0 ng/g. However, it has extremely high abundance in Co-rich crusts, marine polymetallic nodules, deep-sea sediments and aerolites. To find out the origin of tellurium enrichment in deep-sea sediments, we analyzed and compared tellurium concentrations and helium isotope compositions in the magnetic parts and those in the bulk parts of deep-sea sediments. The result indicates that the helium content, 3He/4He ratio and tellurium concentration are obviously higher in the magnetic parts than those in the bulk parts. The 3He abundance varies synchronously with the tellurium concentration. 3He and Te have a distinct positive correlation with each other. It is the first time that the paper brings forward that the extreme enrichment of tellurium in deep-sea sediments, like helium isotope anomalies, probably results from the input of interplanetary dust particles （IDPs）. Similarly, the extreme enrichment of tellurium in marine polymetallic nodules and Co-rich crusts is possibly related to IDPs.

Multifunctional diamond-based catalysts:Promising candidates for energy conversions in extreme environments-A mini-review

In order to properly utilize the abundant CO_(2)and water resources,various catalytic materials have been developed to convert them into valuable chemicals as renewable fuels electrochemically or photochemically.Currently,most studies are conducted under mild laboratory conditions,but for some extreme environments,such as Mars and space stations,there is an urgent need to develop new catalysts satisfying such special requirements.Conventional catalytic materials mainly focus on metals and narrow bandgap semiconductor materials,while the research on wide and ultrawide bandgap materials that can inherently withstand extreme conditions has not received enough attention.Given the robust stability and excellent physico-chemical properties of diamond,it can be expected to perform in harsh environments for electrocatalysis or photocatalysis that has not been investigated thoroughly.Here,this review summarizes the catalytic functionality of diamond-based electrodes with various but tunable product selectivity to obtain the varied C_(1)or C_(2+)products,and discusses some important factors playing a key role in manipulating the catalytic activity.Moreover,the unique solvation electron effect of diamond gives it a significant advantage in photocatalytic conversions which is also summarized in this mini-review.In the end,prospects are made for the application of diamond-based catalysts under various extreme conditions.The challenges that may be faced in practical applications are also summarized and future breakthrough directions are proposed at the end.

The extremotolerant desert moss Syntrichia caninervis is a promising pioneer plant for colonizing extraterrestrial environments

Many plans to establish human settlements on other planets focus on adapting crops to growth in controlled environments.However,these settlements will also require pioneer plants that can grow in the soils and harsh conditions found in extraterrestrial environments,such as those on Mars.Here,we report the extraordinary environmental resilience of Syntrichia caninervis,a desert moss that thrives in various extreme environments.S.caninervis has remarkable desiccation tolerance;even after losing>98%of its cellular water content,it can recover photosynthetic and physiological activities within seconds after rehydration.Intact plants can tolerate ultra-low temperatures and regenerate even after being stored in a freezer at80C for 5 years or in liquid nitrogen for 1 month.S.caninervis also has super-resistance to gamma irradiation and can survive and maintain vitality in simulated Mars conditions;i.e.,when simultaneously exposed to an anoxic atmosphere,extreme desiccation,low temperatures,and intense UV radiation.Our study shows that S.caninervis is among the most stress tolerant organisms.This work provides fundamental insights into the multi-stress tolerance of the desert moss S.caninervis,a promising candidate pioneer plant for colonizing extraterrestrial environments,laying the foundation for building biologically sustainable human habitats beyond Earth.

Exploring the nonlinear piezoresistive effect of 4HSiC and developing MEMS pressure sensors for extreme environments

Microelectromechanical system(MEMS)pressure sensors based on silicon are widely used and offer the benefits of miniaturization and high precision.However,they cannot easily withstand high temperatures exceeding 150 ℃ because of intrinsic material limits.Herein,we proposed and executed a systematic and full-process study of Sic-based MEMS pressure sensors that operate stably from-50 to 300 ℃.First,to explore the nonlinear piezoresistive effect,the temperature coefficient of resistance(TCR)values of 4H-SiC piezoresistors were obtained from-50 to 500 ℃.A conductivity variation model based on scattering theory was established to reveal the nonlinear variation mechanism.Then,a piezoresistive pressure sensor based on 4H-SiC was designed and fabricated.The sensor shows good output sensitivity(3.38 mVN/MPa),accuracy(0.56%FS)and low temperature coefficient of sensitivity(TCS)(-0.067%FS/℃)in the range of-50 to 300 ℃.In addition,the survivability of the sensor chip in extreme environments was demonstrated by its anti-corrosion capability in H_(2)SO_(4) and NaOH solutions and its radiation tolerance under 5 W X-rays.Accordingly,the sensor developed in this work has high potential to measure pressure in high-temperature and extreme environments such as are faced in geothermal energy extraction,deep well dilling,aeroengines and gas turbines.

Observed Trends in Extreme Temperature over the Klang Valley, Malaysia

This study investigates the recent extreme temperature trends across 19 stations in the Klang Valley, Malaysia, over the period 2006^-16. Fourteen extreme index trends were analyzed using the Mann-Kendall non-parametric test, with Sen’s slope as a magnitude estimator. Generally, the annual daily mean temperature, daily mean maximum temperature, and daily mean minimum temperature in the Klang Valley increased significantly, by 0.07°C yr^-1, 0.07°C yr^-1 and 0.08°C yr^-1, respectively. For the warm temperature indices, the results indicated a significant upward trend for the annual maximum of maximum temperature, by 0.09°C yr^-1, and the annual maximum of minimum temperature, by 0.11°C yr^-1. The results for the total number of warm days and warm nights showed significant increasing trends of 5.02 d yr^-1 and 6.92 d yr^-1, respectively. For the cold temperature indices, there were upward trends for the annual minimum of maximum temperature, by 0.09°C yr^-1, and the annual minimum of minimum temperature, by 0.03°C yr^-1, concurrent with the decreases in the total number cold days (TX10P), with -3.80 d yr^-1, and cold nights (TN10P), with -4.33 d yr^-1. The 34°C and 37°C summer days results showed significant upward trends of 4.10 d yr^-1 and 0.25 d yr^-1, respectively. Overall, these findings showed upward warming trends in the Klang Valley, with the minimum temperature rate increasing more than that of the maximum temperature, especially in urban areas.

Formation and evolution mechanism of metal whiskers in extreme aerospace environments:A review

The spontaneous growth and evolution mechanism of metal whiskers have long been scientific problems.With the development of the integration of electronic and electrical productions,short circuits and system failures are raised by metal whiskers continuously.In the meantime,the related theories and mechanisms of whiskering problem are still vague,leading to a deficiency in the studies of environmental factors influencing the whisker phenomenon.Besides,the extreme environments such as aerospace,have been proven the accelerators to the formation of metal whiskers,resulting in a severe threaten to equipment and devices working in such environments including satellite and military equipment.To establish a comprehensive understanding to the whiskering process associated with their applicable control strategies,this study analyzes the growth phenomenon,influencing factors,formation process and evolution mechanism of metal whiskers in extreme service environments,puts forward the corresponding controlling strategies,offers a reference for the establishment of Chinese extreme aerospace strategic environment,and improves the reliability of aerospace systems.

地外建造研究进展与科学技术挑战

随着深空科学与深空探测技术的不断发展,NASA、ESA以及其他一些国家纷纷提出地外空间中长期驻留设想及其地外建造相关计划。该文梳理了国内外地外建造相关战略,系统分析了地外建造的概念内涵及其发展;总结了地外建造结构设计、材料制备和建造工艺装备三方面研究进展;进而分析指出地外建造关键科学技术挑战。期待更多的学者关注地外建造这一新的研究领域,为我国深空探测贡献土木工程学科智慧。

复杂载荷、极端环境下焊接结构疲劳寿命预测研究综述

焊接接头易出现缺陷和应力集中,在疲劳载荷作用下将成为疲劳裂纹萌生和扩展的薄弱区域。与均质材料相比,接头各区域微观组织及应力局部化使得焊接结构疲劳问题进一步复杂化。区别于理想实验条件,实际焊接结构服役环境复杂,疲劳寿命预测须考虑环境因素与焊接结构耦合特性。为此,对影响焊接结构的内在因素进行总结分析,从复杂载荷和极端服役环境两方面对现有焊接结构寿命预测模型进行综述,结合最新研究进展对改进焊接结构疲劳寿命评估方法提出建议。

激光冲击强化技术在核电领域的研究进展

激光冲击强化技术属于改善金属性能的重要表面形变强化技术,因其独特的技术优势在航天及船舶领域获得广泛应用。随着科技的发展研发出多种激光冲击强化技术,并逐渐开始在核电装备领域获得应用,然而针对该技术在核电领域的研究进展缺乏系统的综述。先通过介绍不同表面形变强化技术,叙述激光冲击强化技术的发展,阐述激光冲击强化机制,最后综述激光冲击强化技术在核电领域的应用研究进展。总结发现,激光冲击强化技术可有效改善核电领域材料力学、摩擦磨损及腐蚀性能,但传统和添加辅助手段激光冲击强化技术受约束层和吸收层影响较大,无涂激光冲击强化技术对金属易产生热效应,飞秒激光冲击强化影响层浅且强化效果差,不同工艺技术在核电领域提升摩擦磨损性能研究较少。对不同工艺激光冲击强化机理及在核电领域材料不同性能的提升进行深入研究,为进一步提升激光冲击强化技术在核电领域材料的应用提供理论基础,可为核电领域关键装备进行强化、提升核电装备运行寿命提供参考。

极端环境隧道建造面临的主要问题及发展趋势

聚焦艰险山区、深水海域与城市敏感区3类极端环境,全面梳理和总结了在此环境下隧道建造面临的主要问题、相关技术突破和未来发展趋势。针对艰险山区中极高地应力、高地温、高海拔以及活动断裂带等极端条件,总结分析围岩和隧道的变形机制、破坏机制及防护措施,并指出未来可通过大数据、机器学习等手段建立更精准的预测模型,以实现隧道建造过程的实时监控和风险评估;针对深水海域中高水压、高烈度地震、强侵蚀环境等极端条件,分析多因素耦合下沉管法及盾构法隧道管片及接头的劣损和破坏机制,总结提升其力学和耐久性能的主要技术措施,并提出未来仍需针对海底隧道管片接头的防水、抗震及抗侵蚀性能开展更深入的研究,以形成完整的理论和技术体系;针对城市敏感区隧道穿越既有隧道、敏感建构筑物、地下障碍物等挑战,总结分析盾构法和顶管法施工环境响应规律、地层变形评估方法和控制技术措施,提出未来可采用机器学习等技术辅助隧道建设,以提升预测和控制的准确性,减小建设过程对城市环境的扰动。目前,相关研究成果为极端环境下的隧道工程建设提供了重要支撑,但部分技术仍需进一步在实践中完善并形成规范,以指导后续的工程建设;而随着新一代信息技术的发展,未来隧道建造必将朝着数字化、智能化、自动化的方向发展,从而保障极端环境下隧道建设的安全、绿色、高效。

健康城市视角下建成环境对步行效率影响研究——以兰州市城关核心片区为例

步行是体力活动的重要组成部分,步行出行对于减轻交通拥堵、促进邻里交往及推动居民身心健康具有重要的现实意义。以兰州市城关核心片区为研究区域,基于百度地图步行时间数据及兰州市建成环境要素数据,利用极限梯度提升模型探讨了建成环境对步行出行效率的影响机理。结果表明:(1)对步行出行效率影响较显著的建成环境要素分别为断头路口密度(0.24)、支路与街巷比(0.22)、地块数量密度(0.13)、公交线密度(0.09)、公交站密度(0.08)及土地混合度(0.07)。(2)各建成环境要素与步行出行效率之间呈现复杂的非线性相关关系。从提倡小尺度街道、土地功能混合使用、合理布局公共交通三个方面提出提高步行出行效率的步行空间优化策略。

面向极端环境的石墨烯人工表面等离激元天线阵

面向极端环境中的通信与探测需求,提出一种石墨烯人工表面等离激元天线阵。该天线采用高导电石墨烯薄膜材料制成,结构形式为人工表面等离激元。其中,人工表面等离激元电磁结构分为传输段与辐射段,传输段用以实现显著的慢波特性与场局域性,进而获得低剖面与小型化;辐射段用以实现高定向性的端射辐射,并进行方向图合成。高导电石墨烯薄膜使天线拥有多种物化环境下的耐受性。经仿真与实测验证,天线整体剖面为50μm,在1000次弯折试验、-200~200℃高低温试验、酸性试验、碱性试验、盐雾试验的极端条件试验后,能够提供5.5~6.5 GHz频段范围内S11参数小于-10 dB良好的阻抗匹配,工作带宽内峰值增益为9.3 dBi。

缓步动物生物学研究及其对生物医学的启示

缓步动物是一类具有隐生能力的真核生物,其独特的抗逆能力(耐极寒、耐高温、抗辐射、耐高压)以及能可逆地进行脱水及水化的特点使之成为多个领域的重要研究对象。本文综述了缓步动物强耐受能力生物学机制的主要研究进展,总结了基于缓步动物抗逆特性的生物医学研究与仿生应用研究,讨论了其在极端环境生物医学领域中的启示意义。

青藏高原微生物生态功能研究进展

青藏高原作为地球“第三极”和全球气候变化敏感区,有着复杂和极端的气候环境,同时也蕴藏了丰富而特殊的生物资源,因此其生物多样性及其对全球气候变化的响应等研究备受关注。随着免培养的分子生态学和高通量测序等技术的迅速发展,青藏高原微生物的多样性及其功能、与其他生物互作等方面的研究不断深入,人们得以进一步认识青藏高原微生物在调节和维持生态系统平衡稳定等方面的重要作用。本文以青藏高原微生物合成功能中的固碳、固氮和藏区特色食品生产和分解作用中的碳、氮、磷、硫元素循环和有毒有害物质的降解以及共生作用中的与微生物、动物、植物共生为主要内容,讨论了微生物对青藏高原其他物种以及生态环境等方面的独特贡献,并对其生态功能进行总结,明确青藏高原微生物对于其脆弱生态环境的重要意义,以期为青藏高原生物多样性保护及微生物资源的开发利用提供参考。