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.

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.

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.

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.

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.

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.

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.

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.

长期航天任务中的心理变化:来自中国乘组的启示

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.

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.

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.

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.

Multifunctional protective aerogel with superelasticity over−196 to 500℃

Protective materials that possess superelasticity and multifunctionality over a broad temperature range are urgently needed in various advanced applications.However,under harsh work conditions,the performance of current materials may largely deteriorate to lose protective functionality.Herein,we report a bidirectionally oriented multi-walled carbon nanotubes(MWCNTs)-reinforced chitosan carbon aerogel(CS-MWCNT)that possesses superelasticity,high electromagnetic interference shielding,thermal insulation,and infrared stealth at both low temperatures(such as liquid nitrogen)and high temperatures(such as alcohol flames).Highly oriented lamellar arch structures combined with an MWCNTs-reinforced carbon skeleton act as elastic segments to disperse the stress during compression and endow CS-MWCNT with the ability to recover to almost the original size after being compressed at−196-500℃.The lamellar structures make CS-MWCNT thermally insulating and infrared stealth with a low thermal conductivity of~0.03 W/(m·K).Furthermore,a high electromagnetic interference(EMI)shielding effect of 64 dB is realized via an absorption-dominant EMI shielding mechanism derived from the successive inherently conductive carbon lamella,and the EMI shielding performance is largely maintained after treatment under extreme conditions like low temperature,high temperature,as well as cyclic compression.This work provides a new strategy for the development of temperature-invariant multifunctional aerogels for harsh environment applications.

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.