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.

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.

Genomic Convergence in the Adaptation to Extreme Environments

Convergent evolution is especially common in plants that have independently adapted to the same extreme environments(i.e.,extremophile plants).The recent burst of omics data has alleviated many limitations that have hampered molecular convergence studies of non-model extremophile plants.In this review,we summarize cases of genomic convergence in these taxa to examine the extent and type of genomic convergence during the process of adaptation to extreme environments.Despite being well studied by candidate gene approaches,convergent evolution at individual sites is rare and often has a high false-positive rate when assessed in whole genomes.By contrast,genomic convergence at higher genetic levels has been detected during adaptation to the same extreme environments.Examples include the convergence of biological pathways and changes in gene expression,gene copy number,amino acid usage,and GC content.Higher convergence levels play important roles in the adaptive evolution of extremophiles and may be more frequent and involve more genes.In several cases,multiple types of convergence events have been found to co-occur.However,empirical and theoretical studies of this higher level convergent evolution are still limited.In conclusion,both the development of powerful approaches and the detection of convergence at various genetic levels are needed to further reveal the genetic mechanisms of plant adaptation to extreme environments.

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.

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.

Research Progress on the Solder Joint Reliability of Electronics Using in Deep Space Exploration

The spacecraft for deep space exploration missions will face extreme environments,including cryogenic temperature,intense radiation,wide-range temperature variations and even the combination of conditions mentioned above.Harsh environments will lead to solder joints degradation or even failure,resulting in damage to onboard electronics.The research activities on high reliability solder joints using in extreme environments can not only reduce the use of onboard protection devices,but effectively improve the overall reliability of spacecraft,which is of great significance to the aviation industry.In this paper,we review the reliability research on SnPb solder alloys,Sn-based lead-free solder alloys and In-based solder alloys in extreme environments,and try to provide some suggestions for the follow-up studies,which focus on solder joint reliability under extreme environments.

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.

An analysis of Great Salt Lake Winogradsky columns

Sergei Winogradsky illuminated revolutionary concepts and produced a tool to visualize complex microbial communities and their metabolisms over time:columns displaying aquatic consortia with variety of niches.We worked with museums in Utah to create Winogradsky columns that would highlight aesthetic properties of the Great Salt Lake(GSL)ecosystem,which has a salinity gradient from the freshwater wetlands to salt saturation.One column,constructed using haloarchaea-rich hypersaline brine and oolitic sand of the lake’s north arm,was enriched with nutrients,and resulted in the desired pink hue over time.After a seven-year maturation period,we examined the microbial taxa present in the water through 16 S/18 S rRNA and Internal Transcribed Spacer(ITS)gene sequencing.A pigment analysis revealed an abundance of bacteriochlorophyll a.The presence of this pigment coupled with the DNA sequencing results,suggest that the haloarchaea that dominate the GSL brine,were not responsible for the pink coloration,but instead Gammaproteobacteria,especially Halorhodospira species.Among the eukaryotes,the lack of phytoplankton and the abundance of fungi were noteworthy observations.These data likely relate to the reduction of oxygen in a non-aerated sealed system over time.Our second exhibit had the goal of educating museum goers about the varying salinities of Great Salt Lake.Here we employed three distinct columns of water and sediment from this salinity gradient.Observations of these columns overtime gave us information about invertebrate communities in addition to the microbial consortia.Both installations taught us about comparing an artificial environment in a museum setting to the natural ecosystem.Taken together,we present the data collected and lessons learned from using Winogradsky columns in public spaces for teaching about an important saline lake.

Energy-efficient intermittent liquid heating of lithium-ion batteries in extreme cold using phase change materials

The electrochemical performance of lithium-ion batteries significantly deteriorates in extreme cold.Thus,to ensure battery safety under various conditions,various heating and insulation strategies are implemented.The present study proposes a hybrid heating approach combining active heating with passive insulation.Conceptual experiments were conducted to investigate the effects of phase change materials(PCMs),inlet water temperature,and intermittent pump startup strategies on battery performance.The obtained experimental results demonstrate that low temperatures lead to increased electrochemical impedance and reduced charge–discharge capacity in batteries.Notably,charge transfer resistance of 162 mΩwas observed at-30℃.Herein,the developed PCM-based battery heating system effectively extended the operational capacity of batteries in cold driving conditions and maintained battery warmth by leveraging the superior heat storage capability of the PCM.Additionally,after the switch off of the heating system,the charge capacity of the battery exceeded 80%owing to latent heat.The use of an intermittent heating strategy not only allowed to conserve energy but also maintained adequate heat storage within the battery module.At-30℃,this strategy enhanced the power efficiency of the cooling system by 35.94%with a reduction in capacity of only 0.8%compared to the continuous strategy.

Porous Ultra-high Temperature Ceramics for Ultra-high Temperature Thermal Protection System

Ultra-high temperature ceramics(UHTCs)are a family of borides,carbides and nitrides of transition elements such as hafnium,zirconium,tantalum and niobium.They exhibit the highest known melting points,good mechanical strength,good chemical and thermal stability under certain conditions.In last decade,researchers dedicated to characterize porous UHTCs aiming to develop novel thermal insulating materials that could withstand temperatures over 2000℃.In this article,the preparation and characteristics of porous UHTCs were reviewed.Dry processing,colloidal processing and solution processing routes have been used to prepare porous UHTCs with porosities ranging from 5%to 97%and pore sizes ranging from hundreds of nanometers to hundreds of micrometers.The obtained porous UHTCs are chemically and dimensionally stable at temperatures up to 2000℃ during static state high-temperature thermal aging.

Long Time Series Observations from Antarctica with the International Concordia Explorer Telescope （ICE-T）

The Intemational Concordia explorer telescope （ICE-T） is a f/1.1 Schmidt telescope, 61 cm aperture, with two optical tubes equipped with identical charged coupled devices 10.3× 10.3 k, 9μ pixel size, ultra-wide-fieldwith a total FOV of 65 square degrees. Its aim is to operate at Dome C, the French-Italian Antarctic Station, taking advantage of the long winter night for continuous observations. It is optimized for high precision photometry in two separate filters Sloan g and Sloan i ranging from 100 mmag to 10 mmag （from 9 to16 mag）. Among the scientific tasks there are the detection of hot Jupiters and Super Earths with the transit method, and related magnetic activity of the hosting stars. The 4m Radom dome for ICE-T together with 3 foundation pillars and the cables bundle have been already successfully installed in January 2009.

Psychological Issues in Simulated Space Missions:What We Learn From Chinese Crew

Inspired by the mysteries of the universe,humans have been exploring outer space since the 1950s.Proceeding from I-day(Shenzhou 5)to 6-month(Shenzhou 15)missions,one of the perspectives of Chinese space exploration has shifted from not just how to safely survive but to how to healthily live in outer space.In current review,we introduce some common psychological stressors during space missions and how researchers simulate these stressors on the ground firstly.Then,we briefly introduce classic and state-of-the-art measurements and tools used in measuring the mental state of crew members.Self-reporting questionnaires,behavioral observations,and computerized tests are widely used as measurement strategies in this field.We discuss,respectively,how challenging missions negatively and positively affect crew members.As psychological issues are sensitive to individual and cultural backgrounds,we focus on Chinese crew members and potential cultural differences.Finally,we propose some potential future directions this research could evolve based on previous findings.

SPACE CARGO TRANSPORT BAGS THROUGH MEMBRANE WATER TREATMENT ELEMENTS TO SPACE ARCHITECTURE BUILDING ELEMENT:A TOTAL PRODUCT SUSTAINABILITY AND LIFE CYCLE DESIGN OPTIMIZATION EXPERIMENT

The CTB Water Wall project is a maximal product life cycle utilization concept study by members of the space architecture design community.Its function is to demonstrate a human space activity Cargo Transport Bag(CTB)that becomes a primary water recycling membrane element after delivery of cargo,and then a permanent architectural building block for sustainable space habitation after its use in water treatment is complete.As such,it is intended as an experiment in radical life cycle product optimization in an extremely mass-constrained application environment(human space operations).It also introduces some fundamentally interesting concepts in architectural use of waste materials in extreme environments.Finally,it is in some ways a simple,tactile and visual demonstration of how far sustainable product design can be taken,if the motivation and technical justification are present.

Correlation of DNA methylation patterns to the phenotypic features of Tibetan elite alpinists in extreme hypoxia

High altitude is an extreme environment that imposes hypoxic pressure on physiological processes,and natives living at high altitudes are more adaptive in certain physiological processes.So far,epigenetic modifications under extreme changes in hypoxic pressures are relatively less understood.Here,we recruit 32 Tibetan elite alpinists(TEAs),who have successfully mounted Everest(8848 m)at least five times.Blood samples and physiological phenotypes of TEAs and 32 matched non-alpinist Tibetan volunteers(non-TEAs)are collected for analysis.Genome-wide DNA methylation analysis identifies 23,202 differentially methylated CpGs(P_(adj)<0.05,|β|>0.1)between the two groups.Some differentially methylated CpGs are in hypoxia-related genes such as PPP1R13L,MAP3K7CL,SEPTI-9,and CUL2.In addition,Gene ontology enrichment analysis reveals several inflammation-related pathways.Phenotypic analysis indicates that 12 phenotypes are significantly different between the two groups.In particular,TEAs exhibit higher blood oxygen saturation levels and lower neutrophil count,platelet count,and heart rate.For DNA methylation association analysis,we find that two CpGs(cg16687447,cg06947206)upstream of PTEN were associated with platelet count.In conclusion,extreme hypoxia exposure leads to epigenetic modifications and phenotypic alterations of TEA,providing us clues for exploring the molecular mechanism underlying changes under extreme hypoxia conditions.

What are extreme environmental conditions and how do organisms cope with them？

Severe environmental conditions affect organisms in two major ways. The environment may be predictably severe such as in deserts, polar and alpine regions, or individuals may be exposed to temporarily extreme conditions through weather, presence of predators, lack of food, social status etc. Existence in an extreme environment may be possible, but then to breed or molt in addition can present major bottlenecks that have resulted in the evolution of hormone-behavior adaptations to cope with unpredictable events. Examples of hormone-behavior adaptations in extreme conditions include attenuated testosterone secretion because territoriality and excess courtship may be too costly when there is one opportunity to reproduce. The individual may even become insensitive to testosterone when target areas of the brain regulating reproductive behavior no longer respond to the hormone. A second example is reduced sensitivity to glucocorticoids following acute stress during the breeding season or molt that allows successful reproduction and/or a vital renewal of the integument to endure extreme conditions during the rest of the year. Reduced sensitivity could involve： （a） modulated response of the hypothalamo-pituitary-adrenal axis, （b） reduced sensitivity to high glucocorticoid levels, or （c） a combination of （a） and （b）. Moreover, corticosteroid binding proteins （CBP） buffer responses to stress by reducing the movement of glucocorticoids into target cells. Finally, intracellular enzymes （11 β-hydroxysteroid dehydrogenase and variants） can deactivate glucocorticoids entering cells thus reducing interaction with receptors. These mechanisms have important implications for climate change and increasing extremes of weather [Current Zoology 57 （3）： 363-374, 2011].

Recent advances in optical fiber high-temperature sensors and encapsulation technique[Invited]

In the aerospace field,for aerospace engines and other high-end manufacturing equipment working in extreme environments,like ultrahigh temperatures,high pressure,and high-speed airflow,in situ temperature measurement is of great importance for improving the structure design and achieving the health monitoring and the fault diagnosis of critical parts.Optical fiber sensors have the advantages of small size,easy design,corrosion resistance,anti-electromagnetic interference,and the ability to achieve distributed or quasi-distributed sensing and have broad application prospects for temperature sensing in extreme environments.In this review,first,we introduce the current research status of fiber Bragg grating-type and Fabry–Perot interferometer-type high-temperature sensors.Then we review the optical fiber hightemperature sensor encapsulation techniques,including tubular encapsulation,substrate encapsulation,and metalembedded encapsulation,and discuss the extreme environmental adaptability of different encapsulation structures.Finally,the critical technological issues that need to be solved for the application of optical fiber sensors in extreme environments are discussed.

Two-dimensional MoS_(2)/diamond based heterojunctions for excellent optoelectronic devices:current situation and new perspectives

Two-dimensional(2D)semiconductor molybdenum disulfide(MoS_(2))can be used as n-channel and is considered as a key candidate material to advance the promising development of optoelectronic device.The high thermal conductivity,breakdown voltage,carrier mobility,and high saturation velocity of diamond offer the possibility of making it high-frequency device material in hightemperature and high-power fields.The addition of 2D MoS_(2)nanolayers and nanosheets to diamond thin film to form heterojunction can improve the carrier transport performance of the optoelectronic device in harsh environments.In this perspective,the prospects of 2D MoS_(2)/diamond heterojunction for challenges and new designs of optoelectronic applications are discussed,including photodetectors,memories,transistors,light emission diodes,and electron field emission devices to further explore the development of 2D material device field in complex environments.

Nanostructured steels for advanced structural applications

This vision summarizes the recent advancement of nanostructured steels foradvanced structural applications, foresees possible challenges and pinpoints futuredirections as well as opportunities in this new era of industrial revolution 4.0.