Extreme Temperature Conditions Research Articles

Effects of ambient temperature and humidity on COPD mortality in Ganzhou city, China.

This study used the time series data of Ganzhou city to explore the individual and interaction effects of temperature and humidity on COPD death, and identify vulnerable subgroups of the population. We collected daily COPD mortality and meteorological data in Ganzhou from 2016 to 2019. The nonlinear distribution lag model was used to examine the associations and interaction between daily mean temperature and humidity and COPD mortality. For the total population, male and 65 years old or above, the relative risk (RR) for COPD mortality could be significant at extremely low temperature (3.3 ℃), reaching 1.799 (95% confidence interval [CI]: 1.216, 2.662), 1.894 (95% CI: 1.164, 3.084) and 1.779 (95% CI:1.185, 2.670). Also, at extremely low humidity (47.8%), the risk reached 1.888 (95% CI: 1.217, 2.930), 1.837 (95% CI: 1.066, 3.165) and 2.166 (95% CI: 1.375, 3.414). The cumulative COPD death risk for females was 3.524 (95% CI: 1.340, 9.267) at high temperature (30.7 ℃), 1.953(95% CI: 1.036, 3.683) at low humidity (47.8%) and 1.726 (95% CI: 1.048, 2.845) at high humidity (96.7%). For the total COPD deaths and subgroups, the interaction effects between daily temperature and humidity were not significant (p > 0.05). Both extremely low temperature and low humidity increased the risk of COPD death in Ganzhou city, especially for males and people over 65 years old. Females were more sensitive to extremely high temperature and humidity. Patients with COPD should pay attention to self-protection under extreme temperature and humidity weather conditions.

Research Note: Water applied direct-fed microbial reduced mortality in heat stressed broilers

Pressure to reduce the use of antibiotics in the poultry industry has intensified research on alternative solutions to support intestinal health, including but not limited to direct fed microbials (DFM). Heat stress is known to impact intestinal health and function. The aim of this study was to determine efficacy of a water applied DFM product on broiler performance during the summer period. One of two treatments were randomly allocated to 12 replicate floor pens each: a control treatment and a treatment provided daily with a dual strain DFM comprised of Lactobacillus acidophilus AG01 and Bifidobacterium animalis AG02 at 1 × 108 CFU/bird/d. Each pen contained 20 Ross 308 broilers. All birds were fed the same three-phased wheat- and soybean meal-based diets. Body weight, feed intake, feed conversion ratio, and mortality were measured at d 0, 10, 24, 35, and 42. Due to natural extreme external temperature conditions, all birds were subject to heat stress during the end of the grower phase up to and including the finisher phase. Temperature was on average 5°C higher compared to industry recommendation. No significant differences were found in growth performance between the control and DFM treatment, yet BW at d 42 in both treatments was reduced by 19% compared to the breed standard. The DFM treatment significantly reduced mortality among the birds. Overall mortality from d 1 to d 35 was reduced from 4.58% to 0.42% (P = 0.023) and overall mortality from d 1 to d 42 was reduced from 5.83 to 0.83% (P = 0.027). This was driven by the difference in heat-stress related mortality in the finisher phase from d 25 to d 42, where mortality reached only 0.44% in the DFM treatment versus 2.88% in the unsupplemented control treatment. Post-mortem analysis confirmed heat-stress related hypoxia. In conclusion, the dual strain DFM may have provided improved (intestinal) homeostasis and barrier function allowing increased resilience to heat stress in broilers.

Stony Corals and Their Associated Fauna Residing in Marine Lakes under Extreme Environmental Conditions

Tropical marine lakes are small land-locked marine waterbodies occurring in karstic coastal areas. During biodiversity surveys in 12 marine lakes in Raja Ampat, Southwest Papua province, Indonesia, we recorded at least 37 species belonging to 29 genera of hard corals. Their observed associated symbiont fauna consisted of bivalve molluscs and polychaete worms. Marine lake temperature ranged from 30.0 to 32.5 °C, acidity from pH 7.6 to 8.1, and salinity from 26.4 to 33.2 ppt. This study provides the first inventory of the marginal coral communities in the extreme habitat of marine lakes, under chronic extreme environmental conditions of higher temperatures, land-based nutrient loads, and sedimentation.

Van der Waals Epitaxial Growth of Ultrathin Indium Antimonide on Arbitrary Substrates through Low-Thermal Budget.

III-V semiconductors possess high mobility, high frequency response, and detection sensitivity, making them potentially attractive for beyond-silicon electronics applications. However, the traditional heteroepitaxy of III-V semiconductors is impeded by a significant lattice mismatch and the necessity for extreme vacuum and high temperature conditions, thereby impeding their in situ compatibility with flexible substrates and silicon-based circuits. In this study, a novel approach is presented for fabricating ultrathin InSb single-crystal nanosheets on arbitrary substrates with a thickness as thin as 2.4nm using low-thermal-budget van der Waals (vdW) epitaxy through chemical vapor deposition (CVD). In particular, in situ growth has been successfully achieved on both silicon-based substrates and flexible polyimide (PI) substrates. Notably, the growth temperature required for InSb nanosheets (240°C) is significantly lower than that employed in back-end-of-line processes (400°C). The field effect transistor devices based on fabricated ultrathin InSb nanosheets exhibit ultra-high on-off ratio exceeding 108 and demonstrate minimal gate leakage currents. Furthermore, these ultrathin InSb nanosheets display p-type characteristics with hole mobilities reaching up to 203 cm2 V-1 s-1 at room temperatures. This study paves the way for achieving heterogeneous integration of III-V semiconductors and facilitating their application in flexible electronics.

Reducing energy consumption in a factory and providing an upgraded energy system to improve energy performance

The industrial sector is a major energy consumer worldwide. Much of this consumption is due to air conditioning systems. In regions with extreme temperature conditions, the electricity consumption of these air conditioning systems increases significantly. This study was carried out with the objective of calculating the total energy consumption of the factory and identifying methods to decrease it. Furthermore, an enhanced energy system is suggested to lower energy consumption. This study was carried out with the objective of calculating the total energy consumption of the factory and identifying methods to decrease it. Furthermore, an enhanced energy system is suggested to lower energy consumption. It is also evident that the cooling load decreases by 21,661 kWh when thermal insulation is applied to the walls. Utilizing double-glazed windows for the skylight roof can lead to a reduction in the cooling load by 822 kWh. Additionally, the use of Light-Emitting Diode (LED) bulb lamps in the factory can further decrease the cooling load by up to 14,717 kWh.

Aspergillus oryzae β-D-galactosidase immobilization on glutaraldehyde pre-activated amino-functionalized magnetic mesoporous silica: Performance, characteristics, and application in the preparation of sesaminol

Aspergillus oryzae β-D-galactosidase (β-Gal) efficiently hydrolyzes sesaminol triglucoside into sesaminol, which has higher biological activity. However, β-Gal is difficult to be separate from the reaction mixture and limited by stability. To resolve these problems, β-Gal was immobilized on amino-functionalized magnetic nanoparticles mesoporous silica pre-activated with glutaraldehyde (Fe3O4@mSiO2-β-Gal), which was used for the first time to prepare sesaminol. Under the optimal conditions, the immobilization yield and recovered activity of β-Gal were 57.9 ± 0.3 % and 46.5 ± 0.9 %, and the enzymatic loading was 843 ± 21 Uenzyme/gsupport. The construction of Fe3O4@mSiO2-β-Gal was confirmed by various characterization methods, and the results indicated it was suitable for heterogeneous enzyme-catalyzed reactions. Fe3O4@mSiO2-β-Gal was readily separable under magnetic action and displayed improved activity in extreme pH and temperature conditions. After 45 days of storage at 4 °C, the activity of Fe3O4@mSiO2-β-Gal remained at 92.3 ± 2.8 %, which was 1.29 times than that of free enzyme, and its activity remained above 85 % after 10 cycles. Fe3O4@mSiO2-β-Gal displayed higher affinity and catalytic efficiency. The half-life was 1.41 longer than free enzymes at 55.0 °C. Fe3O4@mSiO2-β-Gal was employed as a catalyst to prepare sesaminol, achieving a 96.7 % conversion yield of sesaminol. The excellent stability and catalytic efficiency provide broad benefits and potential for biocatalytic industry applications.

Water at negative pressure: nuclear quantum effects

Various condensed phases of water, spanning from the liquid state to multiple ice phases, have been systematically investigated under extreme conditions of pressure and temperature to delineate their stability boundaries. This study focuses on probing the mechanical stability of liquid water through path-integral molecular dynamics simulations, employing the q-TIP4P/F potential to model interatomic interactions in flexible water molecules. Temperature and pressure conditions ranging from 250 to 375 K and − 0.3 to 1 GPa, respectively, are considered. This comprehensive approach enables a thorough exploration of nuclear quantum effects on various physical properties of water through direct comparisons with classical molecular dynamics results employing the same potential model. Key properties such as molar volume, intramolecular bond length, H–O–H angle, internal and kinetic energy are analysed, with a specific focus on the effect of tensile stress. Particular attention is devoted to the liquid-gas spinodal pressure, representing the limit of mechanical stability for the liquid phase, at several temperatures. The quantum simulations reveal a spinodal pressure for water of − 286 and − 236 MPa at temperatures of 250 and 300 K, respectively. At these temperatures, the discernible shifts induced by nuclear quantum motion are quantified at 15 and 10 MPa, respectively. These findings contribute valuable insights into the interplay of quantum effects on the stability of liquid water under diverse thermodynamic conditions.

A Temperature Self-Adaptive Electrolyte for Wide-Temperature Aqueous Zinc-Ion Batteries.

The advancement of aqueous zinc-ion batteries (AZIBs) is often hampered by the dendritic zinc growth and the parasitic side reactions between the zinc anode and the aqueous electrolyte, especially under extreme temperature conditions. This study unveils the performance decay mechanism of zinc anodes in harsh environments, characterized by "dead zinc" at low temperatures and aggravated hydrogen evolution and adverse by-products at elevated temperatures. To address these issues, a temperature self-adaptive electrolyte (TSAE), founded on the competitive coordination principle of co-solvent and anions, is introduced. This electrolyte exhibits a dynamic solvation capability, engendering an inorganic-rich solid electrolyte interface (SEI) at low temperatures while an organic alkyl ether- and alkyl carbonate-containing SEI at elevated temperatures. The self-adaptability of the electrolyte significantly enhances the performance of the zinc anode across a broad temperature range. A Zn//Zn symmetrical cell, based on the TSAE, showcases reversible plating/stripping exceeding 16800 h (>700 d) at room temperature under 1mA cm-2 and 1 mAh cm-2, setting a record of lifespan. Furthermore, the TSAE enables stable operation of the zinc full batteries across an ultrawide temperature range of -35 to 75°C. This work illuminates a pathway for optimizing AZIBs under extreme temperatures by fine-tuning the interfacial chemistry.

Challenges and Advances in Wide‐Temperature Electrolytes for Lithium‐Ion Batteries

AbstractLithium‐ion batteries (LIBs) have gained widespread attention due to their numerous advantages, including high energy density, prolonged cycle life, and environmental friendliness. Nevertheless, their electrochemical performance deteriorates rapidly under extreme temperature conditions, accompanied by a series of safety issues. Electrolyte optimization has emerged as a crucial and feasible strategy to expand the operational temperature range of LIBs. This review comprehensively summarizes the challenges, advances, and characterization methodologies of electrolytes at both subzero and elevated temperatures. Initially, it discusses the degradation mechanisms of different types of electrolytes at extreme temperatures, integrates recent advances, and offers insights into future research directions. Subsequently, various experimental techniques are systematically presented to evaluate the fundamental physical properties, stability, and dynamic behaviors of electrolytes in non‐ambient environments. Finally, it also provides relevant computational methods across the electronic, molecular, and macroscopic scales, and explores the application of high‐throughput techniques in this field. This review offers valuable guidance for breaking the working temperature limits of electrolytes and promoting the development of next‐generation LIBs.

Resorcinol/formaldehyde resin-derived carbon conductive network for superior fluorinated graphite based lithium primary batteries

The high energy density of fluorinated graphite (CFx) based lithium primary battery has aroused tremendous attention. However, the nonconductive CFx always induces high interface impedance and low power density. Herein, the carbon conductive network is generated by thermal treatment of resorcinol/formaldehyde (RF) resin on CFx and RF resin spheres (RF RSs), a conductive carbon layer coats on CFx surface, the electrical conductivity of CFx is improved. The oxygen functional groups in incomplete carbonized RF RSs also dedicate to the electrochemical performance of CFx. When different mass ratios of CFx/RF RSs are employed, the cathodes exhibit improved rate performance and voltage plateaus, and the initial voltage delays observed in CFx are significantly reduced. Notably, CFx/RF RSs−13 cathode delivers an impressive discharge capacity of 843.8 mAh g−1 with a voltage plateau of 2.68 V at 10 mA g−1. This leads to the maximum energy density of 2174.9 Wh kg−1 and a peak power density of 18600 W kg−1. Additionally, CFx/RF RSs−13 cathode demonstrates commendable electrochemical stability across a wide temperature spectrum (−20–70 °C). Given these superior electrochemical attributes, the CFx/RF RSs combination holds significant promise for deployment in high-power devices and for standard operations under extreme temperature conditions.

Integrated analysis of intestinal microbiota and transcriptome reveals that a coordinated interaction of the endocrine, immune system and gut microbiota response to heat stress in Litopenaeus vannamei

Due to the ongoing global warming, the risk of heatwaves in the oceans is continuously increasing while our understanding of the physiological response of Litopenaeus vannamei under extreme temperature conditions remains limited. Therefore, this study aimed to evaluate the physiological responses of L. vannamei under heat stress. Our results indicated that as temperature rose, the structure of intestinal and hepatopancreatic tissues was damaged sequentially. Activity of immune-related enzymes (acid phosphatase/alkaline phosphatase) initially increased before decreased, while antioxidant enzymes (superoxide dismutase and glutathione-S transferase) activity and malondialdehyde content increased with rising temperature. In addition, the total antioxidant capacity decreased with rising temperature. With the rising temperature, there was a significant increase in the expression of caspase-3, heat shock protein 70, lipopolysaccharide-induced tumor necrosis factor-α, transcriptional enhanced associate domain and yorkie in intestinal and hepatopancreatic tissues. Following heat stress, the number of potentially beneficial bacteria (Rhodobacteraceae and Gemmonbacter) increased which maintain balance and promote vitamin synthesis. Intestinal transcriptome analysis revealed 852 differentially expressed genes in the heat stress group compared with the control group. KEGG functional annotation results showed that the endocrine system was the most abundant in Organismal systems followed by the immune system. These results indicated that heat stress leads to tissue damage in shrimp, however the shrimp may respond to stress through a coordinated interaction strategy of the endocrine system, immune system and gut microbiota. This study revealed the response mechanism of L. vannamei to acute heat stress and potentially provided a theoretical foundation for future research on shrimp environmental adaptations.

Quantification and visualization of vibration power flow in train-track-bridge coupled system under thermal effects

This paper presents an approach to investigate the effect of temperature on the transmission and distribution of vibration energy for train-track-bridge coupled systems. The vibration of the coupled system can be simulated by integrating the multi-body dynamics model of the train with the finite element models of the track and bridge. The transmission and distribution of vibration energy can be evaluated using a structural intensity method. This approach was implemented to investigate the vibration characteristics of a coupled system under extreme temperature conditions. The system consisted of a CRH2 high-speed train, a CRTS I double-block ballastless track, and an arch bridge. The results show that extreme temperature not only impacts the characteristics of vibration energy transmission in the coupled system but also affects vibration energy distribution. This research provides new insights into vibration control and optimization design for bridges in regions with significant temperature variations.

Whole-genome resequencing of Chinese indigenous sheep provides insight into the genetic basis underlying climate adaptation

BackgroundChinese indigenous sheep are valuable resources with unique features and characteristics. They are distributed across regions with different climates in mainland China; however, few reports have analyzed the environmental adaptability of sheep based on their genome. We examined the variants and signatures of selection involved in adaptation to extreme humidity, altitude, and temperature conditions in 173 sheep genomes from 41 phenotypically and geographically representative Chinese indigenous sheep breeds to characterize the genetic basis underlying environmental adaptation in these populations.ResultsBased on the analysis of population structure, we inferred that Chinese indigenous sheep are divided into four groups: Kazakh (KAZ), Mongolian (MON), Tibetan (TIB), and Yunnan (YUN). We also detected a set of candidate genes that are relevant to adaptation to extreme environmental conditions, such as drought-prone regions (TBXT, TG, and HOXA1), high-altitude regions (DYSF, EPAS1, JAZF1, PDGFD, and NF1) and warm-temperature regions (TSHR, ABCD4, and TEX11). Among all these candidate genes, eight ABCD4, CNTN4, DOCK10, LOC105608545, LOC121816479, SEM3A, SVIL, and TSHR overlap between extreme environmental conditions. The TSHR gene shows a strong signature for positive selection in the warm-temperature group and harbors a single nucleotide polymorphism (SNP) missense mutation located between positions 90,600,001 and 90,650,001 on chromosome 7, which leads to a change in the protein structure of TSHR and influences its stability.ConclusionsAnalysis of the signatures of selection uncovered genes that are likely related to environmental adaptation and a SNP missense mutation in the TSHR gene that affects the protein structure and stability. It also provides information on the evolution of the phylogeographic structure of Chinese indigenous sheep populations. These results provide important genetic resources for future breeding studies and new perspectives on how animals can adapt to climate change.

The rooftop cooling potentials of evaporative cooling porous tiles and high reflective coatings in hot and humid regions

Altering the reflectivity and permeability of surfaces in high-density cities is a key approach to mitigate rising urban heat islands. High Reflectance Coatings (HRC) and Evaporative Cooling Porous Tiles (ECPT) offer potential solutions for urban cooling. However, previous studies have mainly focused on roof surface temperatures, neglecting changes in near-roof air temperature. ECPT, a new permeable material, is mostly used in urban pavements and ignoring the underutilized rooftops, with limited research on its cooling effects in these settings. Therefore, this study investigates the impact of HRC and ECPT on near-roof air temperatures in the Pearl River Delta through observational experiments under various weather conditions. The results show that both HRC and ECPT significantly reduce near-roof air temperatures, but their effectiveness decreases above 1.8 m. In rainy conditions, these strategies are less effective due to their dependence on solar radiation. HRC works by reflecting short-wave radiation, while ECPT cools by evaporation. A key advantage of ECPT is its ability to be actively watered, quickly reducing temperatures by 2.14 °C at 0.3 m. This research is valuable for developing urban cooling strategies in high-density areas during extreme temperature conditions.

Temperature-dependent pinned joint tensile behavior and failure analysis of CF/PEKK composites

The pinned joint tensile properties and failure behaviors of carbon-fiber-reinforced polyetherketoneketone (CF/PEKK) composites are sensitive to application temperatures. Herein, this study investigated the temperature-dependent mechanical behavior of CF/PEKK composites in a pinned joint configuration, emphasizing the impact on tensile behavior and bearing strength. Utilizing Solvay’s CF/PEKK prepreg with a quasi-isotropic stacking sequence, tensile tests were conducted at [Formula: see text]C and 230∘C. At [Formula: see text]C, increased load-pin displacement stiffness was observed, attributed to reduced polymer chain mobility, leading to increased peak load and concentrated bearing area around the pin contact region. Conversely, at 230∘C, a substantial reduction in stiffness and peak load was evident, emphasizing the severe deterioration of pin-load strength. Fracture analysis revealed distinct failure modes at different temperatures, highlighting localized compressive failure at [Formula: see text]C and severe permanent bearing failure at 230∘C. Understanding these temperature-dependent behaviors is critical for optimizing CF/PEKK composite applications in diverse industrial settings, providing insights for enhanced performance and reliability. The findings offer valuable information on the material’s behavior under extreme temperature conditions, contributing to the design and application of CF/PEKK composites in various industrial scenarios.

Frictional Slip and Incremental Dynamic Analysis of Plate-rubber Bearing Continuous Girder Bridge by Ambient Temperature in Cold Region

Special mechanical environment, the environmental temperature or stress transformation easily to the final mechanical properties of the bridge components performance changes. The impact of the cold zone environment on the plate rubber-bearing beams is the object of study, Jining Road refined mechanics finite element analysis of the structural dynamic response study under seismic action. The results show that low temperature leads to bearing friction slip and material parameter changes, which affects the self-oscillation frequency and seismic susceptibility of the bridge. Due to the temperature-induced changes in the material properties and mechanical properties of the bearings, the first principal period of the bridge increases by 3% at high temperature for the EH and decreases by 19% at low temperature for the EL when compared to the first principal period under normal temperature conditions. Under different extreme temperature conditions, the fundamental period of the bridge is longitudinal, and the effective mode vibration participation mass is more than 90%. The maximum crossover frequency VALmax reaches 75.6 dB. Compared with room temperature, the bearing stress increased by 27.6% to 45.5%. The effect of EL stress change should be considered in the design of bridges in the alpine region.

Soft Robotic Textiles for Adaptive Personal Thermal Management.

Thermal protective textiles are crucial for safeguarding individuals, particularly firefighters and steelworkers, against extreme heat, and for preventing burn injuries. However, traditional firefighting gear suffers from statically fixed thermal insulation properties, potentially resulting in overheating and discomfort in moderate conditions, and insufficient protection in extreme fire events. Herein, an innovative soft robotic textile is developed for dynamically adaptive thermal management, providing superior personal protection and thermal comfort across a spectrum of environmental temperatures. This unique textile features a thermoplastic polyurethane (TPU)-sealed actuation system, embedded with a low boiling point fluid for reversible phase transition, resembling an endoskeleton that triggers an expansion within the textile matrix for enhanced air gap and thermal insulation. The thermal resistance improves automatically from 0.23 to 0.48Km2W-1 by self-actuating under intense heat, exceeding conventional textiles by maintaining over 10°C cooler temperatures. Additionally, the knitted substrate incorporated into the soft actuators can substantially mitigate convective heat transfer, as evidenced by the thermal resistance tests and the temperature mapping derived from numerical simulations. Moreover, it boasts significantly increased moisture permeability. The thermoadaptation and breathability of this durable all-fabric system signify considerable progress in the development of protective clothing with high comfort for dynamic and extreme temperature conditions.

Modeling and analysis of minor seal leakages in high-pressure hydrogen valves under extreme environmental temperatures

The damage to the sealing rings of high-pressure hydrogen valves caused by extreme environmental temperatures, leading to minor hydrogen leakage, is a significant issue in the field of hydrogen safety. However, current understanding is still limited regarding the initial leakage of hydrogen through damaged gaps in sealing rings. This paper aims to explore the distribution of hydrogen leakage in sealing rings with various-shaped damage gaps under extreme environmental temperatures. Firstly, the real damage gaps of the sealing rings are obtained on an extreme temperature experimental platform. Then, a coupled hydrogen leakage model is established, which calculates the viscosity of hydrogen in real-time as temperature changes. Based on these models, the concentration, temperature, and velocity distribution of hydrogen within the sealing ring gaps under extreme environmental temperatures are studied. The results indicate that the high-pressure hydrogen within the gaps, influenced by viscosity and wall adhesion effects, tends to diffuse along the wall surfaces. The high-temperature zone along the edge lines of the gaps lasts longer than that on the centerline. Under extreme high temperature conditions, the average velocity at the inlet and outlet of the gap is 21.6% higher than under extreme low temperatures.

Regulating interfacial chemistry and kinetic behaviors of F/Mo co-doping Ni-rich layered oxide cathode for long-cycling lithium-ion batteries over −20 °C–60 °C

Ni-rich layered oxide cathodes have shown promise for high-energy lithium-ion batteries (LIBs) but are usually limited to mild environments because of their rapid performance degradation under extreme temperature conditions (below 0 °C and above 50 °C). Here, we report the design of F/Mo co-doped LiNi0.8Co0.1Mn0.1O2 (FMNCM) cathode for high-performance LIBs from −20 to 60 °C. F– doping with high electronegativity into the cathode surface is found to enhance the stability of surface lattice structure and protect the interface from side reactions with the electrolyte by generating a LiF-rich surface layer. Concurrently, the Mo6+ doping suppresses phase transition, which blocks Li+/Ni2+ mixing, and stabilizes lithium-ion diffusion pathway. Remarkably, the FMNCM cathode demonstrates excellent cycling stability at a high cutoff voltage of 4.4 V, even at 60 °C, maintaining 90.6% capacity retention at 3 C after 150 cycles. Additionally, at temperatures as low as −20 °C, it retains 77.1% of its room temperature capacity, achieving an impressive 97.5% capacity retention after 500 cycles. Such stable operation under wide temperatures has been further validated in practical Ah-level pouch-cells. This study sheds light on both fundamental mechanisms and practical implications for the design of advanced cathode materials for wide-temperature LIBs, presenting a promising path towards high-energy and long-cycling LIBs with temperature adaptability.

The collapse of a sonoluminescent cavitation bubble imaged with X-ray free-electron laser pulses

Single bubble sonoluminescence (SBSL) is the phenomenon of synchronous light emission due to the violent collapse of a single spherical bubble in a liquid, driven by an ultrasonic field. During the bubble collapse, matter inside the bubble reaches extreme conditions of several gigapascals and temperatures on the order of 10000 K, leading to picosecond flashes of visible light. To this day, details regarding the energy focusing mechanism rely on simulations due to the fast dynamics of the bubble collapse and spatial scales below the optical resolution limit. In this work we present phase-contrast holographic imaging with single x-ray free-electron laser (XFEL) pulses of a SBSL cavitation bubble in water. X-rays probe the electron density structure and by that provide a uniquely new view on the bubble interior and its collapse dynamics. The involved fast time-scales are accessed by sub-100 fs XFEL pulses and a custom synchronization scheme for the bubble oscillator. We find that during the whole oscillation cycle the bubble’s density profile can be well described by a simple step-like structure, with the radius R following the dynamics of the Gilmore model. The quantitatively measured internal density and width of the boundary layer exhibit a large variance. Smallest reconstructed bubble sizes reach down to R≃0.8μm , and are consistent with spherical symmetry. While we here achieved a spatial resolution of a few 100 nm, the visibility of the bubble and its internal structure is limited by the total x-ray phase shift which can be scaled with experimental parameters.