Medium Energy Research Articles

A comparative AIMD study of electronic excitation-induced amorphization in 3C-SiC, TiC, and ZrC

In the present study, an ab initio molecular dynamics (AIMD) method was employed to investigate the effect of electronic excitation on the micro-structural evolution of 3C-SiC, TiC, and ZrC. The AIMD results demonstrated that electron excitation induces a crystalline-to-amorphous phase transition in all carbide compounds. The determined threshold electronic excitation concentration for 3C-SiC, TiC, and ZrC at 300 K is 4.06%, 5.28%, and 4.26%, respectively. The mean square displacement of C atoms is larger than those of Si, Zr, and Ti atoms, which results from the smaller atomic mass of the C atom. These results indicate that the structural amorphization of 3C-SiC, TiC, and ZrC is primarily attributed to the displacement of C atoms. It is noted that amorphization induced by electronic excitation represents a solid–solid transition rather than a solid–liquid transition. It is further verified that the ⟨Si−C⟩ bond is a covalent characteristic, whereas the ⟨Ti−C⟩ or ⟨Zr−C⟩ bond is a mixture of ionic, metallic, and covalent characteristics, which may lead to different radiation tolerances of carbide compounds. The present results suggest that electronic excitation may contribute to the structural amorphization of carbides under low- or medium-energy electron and ion irradiation, and advance the fundamental comprehension of the radiation resistances of carbide compounds.

Enhanced Crystallinity of SrTiO3 Films on a Silicon Carbide Substrate: Structural and Microwave Characterization

Thin films of strontium titanate, which reveal high structure quality and tunable properties prospective for microwave applications at room temperature, were grown on a semi-insulating silicon carbide substrate using magnetron sputtering for the first time. The films’ growth mechanisms were studied using medium-energy ion scattering, and the films’ structures were investigated using X-ray diffraction. The electrical characteristics of planar capacitors based on strontium titanate films were measured at a frequency of 2 GHz using a high-precision resonance technique. It is shown that the tendency to improve the crystalline structure of strontium titanate film with an increase in the substrate temperature is most pronounced for films deposited at elevated working gas pressure under low supersaturation conditions. Planar capacitors formed on the basis of oriented SrTiO3 films on silicon carbide showed tunability n = 36%, with a loss tangent of 0.008–0.009 at a level of slow relaxation of capacitance, which is significantly lower than the data published currently regarding planar tunable ferroelectric elements. This is the first successful attempt to realize a planar SrTiO3 capacitor on a silicon carbide substrate, which exhibits a commutation quality factor more than 2500 at microwaves.

Study on the heat transfer performance of coaxial casing heat exchanger for medium and deep geothermal energy in cold regions

To accurately assess the heat transfer performance of a medium-depth coaxial casing heat exchanger, this study introduced the concepts of the annual stabilized mining stage and the effective thermal influence distance for each layer of non-homogeneous thermal storage. The study area was stratified into six layers based on the geothermal temperature gradient fitting results. The findings revealed that the maximum injected circulating fluid temperature for the mid-depth coaxial casing geothermal system was 37 °C, with a maximum mass flow rate of 16.67 kg/s. When the injected circulating fluid temperature increased from 2 °C to 25 °C, the duration of the annual stabilized exploitation stage extended from 23 to 26 years. Similarly, increasing the injected circulating fluid mass flow rate from 2.78 kg/s to 16.67 kg/s prolonged the maintenance period in the annual stable mining stage from 22 to 28 years. The study further indicated that the effective thermal influence distance for each layer of thermal storage was significantly impacted by varying injection circulating fluid temperatures. These results offered theoretical insights into the heat transfer performance of medium-depth coaxial casing geothermal systems under both short- and long-term operational conditions.

A new rhynchonellid fauna (Brachiopoda) from the Wordian (middle Permian) of Coahuila, Mexico: Stratigraphy and paleoenvironments

Seven brachiopod species of the order Rhynchonellida of a new locality (Las Margaritas I section) from the Las Delicias Formation in Coahuila, Mexico are described. The fauna includes four taxa identified as Bryorhynchus bisulcatum, Leiorhynchioidea schucherti, Leiorhynchoidea amygdaloidea, and Paranorella imperialis, as well as three species assigned with open nomenclature: Leiorhynchioidea cf. scelesta, Stenoscisma sp., and Rhynchopora sp. The brachiopod fauna identified, together with the record of different middle Permian ammonoids allowed us to establish a Wordian (middle Guadalupian) age for the Las Margaritas I section. The assignment of this relative age enabled restricting the stratigraphic range of Leiorhynchioidea schucherti and Paranorella imperialis to the middle Guadalupian since previously had only been related inaccurately to the middle Permian. The record of the species Bryorhynchus bisulcatum, Leiorhynchioidea cf. scelesta, and Leiorhynchoidea amygdaloidea, as well as the genus Stenoscisma is the first in Mexico. The preservation of specimens, lithological features, and associated fauna suggest that rhynchonellid brachiopods were deposited in different platform facies: shallow lagoonal or offshore, characterized by low to medium energy, stenohaline conditions, and continuous terrigenous input.

Networks of ion-pairs are responsible for the large differences in the thermal stability of two structurally similar aminopeptidases.

Aminopeptidases are an important class of enzymes for protein metabolism. Leucyl aminopeptidase (PepL) preferably removes leucine from the N-terminus of small peptides. PepL of Lacticaseibacillus casei was observed to be thermally unstable, while a structurally similar aminopeptidase T (AmpT) of Thermus thermophilus is highly stable. To understand the molecular interaction responsible for the large difference in their stability, molecular dynamics simulations were carried out to study the thermal stability of PepL and AmpT at 300 K to 450 K temperature range over 100 ns. PepL sampled a larger conformational space with a rugged free-energy landscape, while AmpT navigated a smoother energy landscape to reach the global minimum. The RMSD, RMSF, radius of gyration and principal component analysis suggested large movements in PepL than in AmpT with an increase in temperature. Analysis of residue-interaction network revealed AmpT possessing a greater number of low, medium and high energy contacts in comparison to PepL. AmpT showed a higher abundance of ion-pair clusters and ionic residues per cluster compared to PepL. Moreover, AmpT retained a greater number of high-energy contacts at elevated temperatures. These findings showed that the inherently lower stability of PepL originates from a comparatively smaller number of contacts and can be pivotal in engineering PepL for higher stability.

Effect of Sm2O3 on thermal, optical, mechanical, gamma and neutron shielding properties of zinc-boro-vanadate glasses

Abstract The effect of Sm2O3 on thermal, optical, mechanical, gamma and neutron shielding properties of newly prepared zinc borovanadate glasses has been investigated. Density is found increased and molar volume decreased with Sm2O3 content. The glass transition temperature ( T g ) , crystallization temperature ( T c ) and the peak crystallization temperature ( T P ) increased with increase of rare earth oxide content. These findings demonstrated an excellent glass-forming ability and thermal stability of the glasses. The optical properties have been explored through UV–vis spectroscopy. The indirect optical band gap energy ( E opt ) decreased from 2.978 to 2.679 eV, Urbach energy ( ∆ E ) increased from 0.273 to 0.299 eV and refractive index increased from 2.403 to 2.489 with increase in Sm2O3. Elastic moduli, Poisson’s ratio, Hardness and fractal bond connectivity were computed theoretically as per Makishima Mackenzie model. It is found that these glasses have appreciable mechanical strength and rigidity. Phy-X/PSD software has been used to determine different radiation shielding characteristics for the energy range 0.015–15 MeV. The mass and linear attenuation coefficients are found higher, and half value layer, tenth value layer and mean free paths are found lower than many radiation shielding glasses quoted in the literature values. The obtained Z eq values varied from 15.828–29.118 for energy range from 0.015 to 15 MeV, which are greater than those reported for several commercial glasses, concretes and rocks. Due to the Compton scattering process, exposure build up and energy absorption factor are found to be highest in the medium energy region. The fast neutron removal cross-sections of the glasses are observed to be significantly high. For the first time, thermally stable and mechanically strong zinc borovanadate glasses mixed with Sm2O3 have been thoroughly investigated for various properties and concluded that these glasses are suitable for optoelectronics and γ-shielding applications.

A physics‐constrained hybrid residual neural network for the prediction of moisture content in a closed‐cycle drying system

AbstractClosed‐cycle drying technology has the advantages of safety, energy saving, and environmental protection, and has a wide application prospect. Due to the multi‐physics and multi‐scale nature of heat/mass transfer in the closed‐cycle drying process, as well as the characteristics of drying medium circulation and energy integration, it is difficult to obtain the product moisture content prediction model in closed‐cycle process based on rigorous closed‐cycle drying process mechanism model. However, accurate monitoring of product moisture content in the closed‐cycle drying process is the key to improving drying quality and process optimization. Aiming at the challenges in predicting moisture content, this paper proposes a physics‐constrained hybrid residual neural network (PC‐HRNN) for soft sensor modelling within a designed closed‐cycle drying system. The characteristic of this proposed method lies in its effective fusion of physics, knowledge, and data. First, a hybrid residual neural network (HRNN) is constructed based on the integration of a physics model and a data‐driven model. The HRNN takes the knowledge from the physics model as its auxiliary features and learns the prediction residuals of the physics model through a neural network model. Then, a new loss function that takes into account physical laws is introduced into HPNN to standardize model training and improve the generalization performance of the model. The experimental results show that the PC‐HRNN model improves prediction accuracy and model robustness, reduces the demand for data, and demonstrates stronger extrapolation capabilities under limited data.

Difference of Sedimentary Characteristics and Main Controlling Factors Between Platform Margin Shoal and Ramp Shoal in M Formation of A Oilfield in The Middle East

Abstract The bioclastic limestone reservoirs of M Formation in A Oilfield mainly develop in the ramp shoal and platform margin shoal, but the sedimentary characteristics, spatial distribution and main controlling factors of the two types of shoals are significantly different. Based on the data of seismic, well logging, core, casting thin sections and analytical tests, the comparative analyses of lithology, petrophysics and spatial distribution of the two types of shoals are carried out, and the control mechanism of relative sea level rise and fall and paleogeomorphology on their development is clarified. It is showed that the two types of shoals can be subdivided according to hydrodynamic conditions and bioclastic types. The platform margin shoals are dominated by grainstone and gravel limestone, and the bioclastics are mainly rudist and echinoderms. The logging curve is funnel-shaped, and the seismic is patchy distribution. In the vertical direction, the grain size of shoals becomes coarser, and the sedimentary sequence of medium energy shoal—medium-high energy shoal—high energy shoal is developed. In the horizontal direction, the facies belts of different shoals are narrow, and they are distributed quasi-layered semi-continuously around high energy shoals. The ramp shoals are dominated by packstone and grainstone, and the bioclastics are mainly non-fixed bivalves and algae. The logging curve is micro-tooth box-shaped, and the seismic is sheet distribution. In the vertical direction, the grain size change of shoals is not significant, and the sedimentary sequence of medium energy shoal—medium-high energy shoal is developed. In the horizontal direction, the facies belts of different shoals are wide, and they are distributed layered continuously around medium-high energy shoals. Relative sea level change controls the energy of sedimentary environment and the type of shoal facies, and the high position of paleogeomorphology controls the formation and distribution of high energy shoals. When the relative sea level is high and the paleogeomorphology is gentle, the ramp shoal is developed. As the relative sea level drops, the hydrodynamic condition increases, and the difference in the accumulation speed of different shoals enhances the fluctuation of the paleogeomorphology, the ramp shoal gradually transitions to the platform margin shoal. The above research can provide reference for the exploration and development of such reservoirs.

The Bicoherence Analysis of Type-C Quasiperiodic Oscillations in Swift J1727.8−1613

We present the results of bicoherence analysis for Swift J1727.8−1613 during its 2023 outburst, using data from Insight-HXMT. Our analysis focused on observations with quasiperiodic oscillations (QPOs) of frequencies greater than 1 Hz, revealing that all of them belong to type-C QPOs. We found a strong correlation between the QPO frequency and the hardness ratio, as well as a linear relationship between the QPO rms and the hardness ratio. The bicoherence analysis revealed a transition from a “web” pattern to a “hypotenuse” pattern in the low-energy (LE) and high-energy (HE) bands. In the bicoherence patterns, there are correlations between horizontal and vertical bicoherence at f 1 = f 2 = f QPO with count rates. The diagonal structure at f 1 + f 2 = f QPO becomes more prominent with increasing energy. Additionally, we discovered a new bicoherence pattern in the medium energy band from 10 to 20 keV; the diagonal structure at f 1 + f 2 = f har is prominent only in this energy band, which we refer to as the “parallel” pattern. The bicoherence analysis indicates that the source is likely a low-inclination source.

The Medium Energy Electron Telescope (MEET): Instrument Fabrication and Testing

AbstractThis manuscript is a follow up study to Hogan et al., (2024, https://doi.org/10.1029/2023JA032221) which describes the science motivation and development of the Medium Energy Electron Telescope (MEET). Medium Energy Electron Telescope is a 1U instrument optimized to measure 30–400 keV electrons in the inner radiation belt with fine energy resolution to resolve dynamics of these populations which are not well understood. Here we present the fabrication and testing of MEET to certify its performance in preparation for in‐space measurements. Assembly of an engineering model is shown. This unit has undergone vibration testing and these results are discussed. The electronics of the instrument are tested after these environmental tests including electron measurements with pulse injection and a radioactive source. Test results indicate the instrument is viable for flight on a potential mission by satisfying noise requirements and reproduction of an input flux spectrum. The noise of expected input signals is quantified to be <∼6 keV allowing for <20% dE/E for 30 keV electrons. Strontium‐90 radioactive source tests were conducted. Using measured count rates from MEET's electron energy channels, we reproduce the strontium‐90 spectrum proving the instrument's ability to measure flux of 30–800 keV electrons with fine nominal energy resolution (<20% dE/E for <60 keV, and <10% for >60 keV electrons). These results demonstrate MEET's performance in a relevant environment via ground testing. Medium Energy Electron Telescope is available for future missions to provide novel electron measurements in the inner radiation belt.

Study on the Evolutionary Process and Balancing Mechanism of Net Load in Renewable Energy Power Systems

With the rapid development of renewable energy sources such as wind and solar, the net load characteristics of power systems have undergone fundamental changes. This paper defines quantitative analysis indicators for net load characteristics and examines how these characteristics evolve as the proportion of wind and solar energy increases. By identifying inflection points in the system’s adjustment capabilities, we categorize power systems into low, medium, and high renewable energy penetration. We then establish adjustment models that incorporate traditional coal power, hydropower, natural gas generation, adjustable loads, system interconnections, pumped-storage hydroelectricity, and new energy storage technologies. A genetic algorithm is employed to optimize and balance the net load curves under varying renewable energy proportions, analyzing the mechanism behind net load balance. A case study, based on real operational data from 2023 for a provincial power grid in western China, which is rich in renewable resources, conducts a quantitative analysis of the system’s adjustment capability inflection point and net load balancing strategies. The results demonstrate that the proposed method effectively captures the evolution of the system’s net load and reveals the mechanisms of net load balancing under different renewable energy penetration levels.

Preparation and thermal properties investigation of pentaerythritol based phase change microcapsules for low and medium temperature thermal energy storage

As one of classic organic compounds, pentaerythritol (PE) has been reported to have two phase-change processes with one solid-solid transition and other solid-liquid transition. To utilize these two phase-change enthalpies and avoid the liquid leakage over heat storage process, this work for the first time proposes to encapsulate PE with use of silicon dioxide (SiO2) as a shell substance through a so-called so-gel technology. The microstructure characterization and thermoproperties as well as the cycling performance of the PE- SiO2 composite are detailedly investigated. The results showed that PE could be successfully covered by SiO2 to form a spherical core-shell structure. Such an encapsulation has a mean size of 0.3 μm and an encapsulated rate of over 77.8 %. Due to the involvement of two phase-transition stages, the latent heat of the PE- SiO2 composite reached to 255 kJ/kg, which is higher than other organic microencapsulations. In addition, the thermal conductivity is largely enhanced by adjusting the ratio of SiO2. For a given SiO2 ratio of 77.8 %, the thermal conductivity of PE-SiO2 composite is 0.93 W/m·K, 36.8 % higher than that of pristine PE. Apart from these, the results also indicated that the composite achieves excellent thermal cycling performance. After one hundred repeated heating-cooling cycles, the latent heat of the PE- SiO2 composite decreases by less than 5 %, demonstrating that this composite material has a large potential for application in the field of thermal energy storage at low and medium temperatures.

Design and commissioning of a two-harmonic pre-buncher for extended bunch spacing at LEAF

The Low Energy Heavy Ion Accelerator Facility (LEAF) is a low-energy, high-intensity heavy-ion linear accelerator facility at Institute of Modern Physics (IMP) for multidiscipline research. The beam bunch repetition rate coincides with the LINAC frequency of 81.25 MHz, resulting in a 12.3 ns period. However, in the context of certain nuclear physics experiments, a longer bunch spacing is deemed essential for the precise detection of experimental products. To address this need, a strategy to extend the bunch spacing to 98 ns has been proposed by integrating a pre-buncher operating at a fundamental frequency of 10.156 MHz before the radio-frequency quadrupole (RFQ) in conjunction with a fast chopper in the medium energy beam transport (MEBT) system. The pre-buncher is a pivotal component in enabling a greater beam current at the target, surpassing the capability of employing a chopper alone. To enhance the bunching efficiency, the pre-buncher operates with two frequencies: the fundamental frequency of 10.156 MHz and its first sub-harmonic of 20.3125 MHz, each of which is produced by a coaxial resonator. This paper describes the design, manufacture, off-line testing, and beam commissioning of the pre-buncher.

Medium and long-term energy demand forecasts by sectors in China under the goal of “carbon peaking & carbon neutrality”: Based on the LEAP-China model

Energy is a critical material foundation for sustainable economic and social development and national security, and it is of great significance to explore China's medium and long-term energy demand to realize the “dual-carbon” goal. Based on the current state of economic and social development and energy consumption, the LEAP-CHINA model is constructed to create baseline scenario, structural adjustment scenario, technology abatement scenario, and comprehensive scenario to forecast China's total energy demand, end-use industry subsectors, end-use energy subvarieties, processing and conversion sectors from 2022 to 2060. The results show: (1) China's total energy demand showed a “rapid increase before 2039, a slow increase between 2039 and 2049, and a gentle decrease after peaking in 2049". (2) The contribution rate of energy conservation and emission reduction was comprehensive scenario > technology abatement scenario > industrial adjustment scenario > baseline scenario > energy adjustment scenario. (3) Industry was the largest energy demand industry, and the rest of the industries' energy demand share was decreasing. (4) There is a definite trend towards power system decarbonization and energy system electrification, with non-fossil energy power generation anticipated to increase to 78%–82 % in 2060. Finally, it proposes countermeasures for China's energy development in the medium and long-term.

The Polarity of IMF By Strongly Modulates Particle Precipitation During High‐Speed Streams

AbstractRecent studies have suggested that the interplanetary magnetic field (IMF) component modulates particle precipitation during solstices, or periods of high dipole tilt . So far this explicit IMF ‐effect has only been shown in statistical studies. Here we analyzed a sequence of high‐speed stream (HSS) driven events of auroral ( keV) and medium energy ( keV and keV) particle precipitation. We show that when HSSs are comparable in terms of IMF and solar wind parameters, they can lead to systematically stronger particle precipitation in individual events when the signs of and are opposite. We also perform a superposed epoch analysis of 485 HSSs giving further evidence that the ‐effect is especially significant during HSSs. This is likely due to the persistent IMF polarity during HSSs. We show evidence that the dependence in particle precipitation is caused by a similar dependence in substorm occurrence.

Techno-economic analysis on a hybrid system with carbon capture and energy storage for liquefied natural gas cold energy utilization

For cold energy utilization in the liquefied natural gas (LNG) regasification process, integrated cryogenic CO2 capture using high-grade cold energy is a mainstream method. However, high-grade cold energy for carbon capture may lead to a decrease in cold energy utilization efficiency. This paper aims to propose a hybrid system in which high-grade cold energy is used for liquid air energy storage (LAES) and post-combustion amine scrubbing technology is considered to replace cryogenic carbon capture for improved working efficiency. The medium and low-grade cold energy is utilized for similar working processes, e.g., organic Rankine cycle (ORC), carbon dioxide liquefaction, and data center cooling for comparison. Results show that the proposed hybrid system can produce 437.7 MW of power, 28.8 t·h−1 of CO2 capture capacity, and 23.0 MW of cooling capacity, respectively. The levelized cost of electricity and the annual revenue are 112.3 $·MWh−1 and 2.17 million $, respectively. LNG cold energy utilization efficiency, system energy efficiency, and cold exergy efficiency are 53.4 %, 24.0 %, and 51.5 %, higher than similar processes using cryogenic CO2 capture. It is demonstrated that the proposed system could be a promising method for cold energy utilization and post-combustion capture.

Effect of Dietary Energy Level during Late Gestation on Mineral Contents in Colostrum, Milk, and Plasma of Lactating Jennies.

This study investigated the effects of dietary energy levels during late gestation on mineral content in the plasma, colostrum, and milk of jennies postpartum. Twenty-four pregnant multiparous DeZhou jennies, aged 6.0 ± 0.1 years, with a body weight of 292 ± 33 kg, an average parity number of 2.7 ± 0.1, and similar expected dates of confinement (74 ± 4 days), were randomly allocated to three groups and fed three diets: high energy (12.54 MJ/kg, HE), medium energy (12.03 MJ/kg, ME), and low energy (11.39 MJ/kg, LE). Blood samples were collected from the jugular vein of each jenny at time points of 0 h, 24 h, 48 h, 5 d, 7 d, and 14 d after parturition. Additionally, milk samples were collected through manual milking, and an analysis of the mineral content was conducted. The results showed that compared with HE, both ME and LE significantly increased the levels of calcium (Ca), phosphorus (P), zinc (Zn), selenium (Se), molybdenum (Mo), and cobalt (Co) in the plasma and Ca, P, magnesium (Mg), copper (Cu), manganese (Mn), Zn, selenium (Se), molybdenum (Mo), and Co in the milk of jennies postpartum (p < 0.05); ME also increased the levels of potassium (K), iron (Fe), and Mn in plasma and K and Fe in milk (p < 0.05). The levels of Ca, K, Mg, P, Fe, Cu, Mn, Co, Se, Zn, and Mo in plasma and milk gradually decreased with increasing postpartum time. Their contents were the highest at 0 h postpartum, rapidly decreased after 24 h postpartum, and declined to the lowest on day 14 postpartum. The interaction between dietary energy level and postpartum time showed that although the concentrations of the minerals Ca, P, K, Mg, Fe, Cu, Mn, Zn, Co, Se, and Mo decreased in jennies' plasma and milk in the treatment groups with different energy levels as postpartum time increased, the pattern of change was also influenced by dietary energy level. The influence of dietary energy level in late gestation on the mineral content of milk and plasma during the postpartum colostrum phase was higher than that during the milk phase. In conclusion, this study demonstrated that, under the current experimental conditions, the mineral content of the colostrum, milk, and plasma of jennies after parturition was dependent on the dietary energy level during late gestation.

Energy efficiency identification and surface roughness prediction using cutting force signal for computer numerical controlled machine systems

The energy efficiency identification of machining process plays an indispensable part in achieving energy-efficient manufacturing and improving energy utilization as well as productivity and surface quality. However, there is a great difficulty to track energy efficiency in real-time based on one kind of traditional power signal. Because energy consumption is affected by many factors such as machine tool current performance, tool wear conditions and cutting parameters selection. This paper puts forward an energy efficiency recognition method as well as surface roughness prediction model based on the cutting force signals. The CEEMDAN (Complete Ensemble Empirical Mode Decomposition with Adaptive Noise) algorithm is employed to decompose the cutting force signal into multiple IMF (intrinsic mode function) components; and characterization of energy efficiency of machining process is recognized through proportion of components based on PCA—Fast ICA algorithm. Then, a surface roughness prediction model is proposed using support vector regression (SVR) based on specific cutting energy consumption (SCEC). The orthogonal test is designed considering spindle speed, feed rate, depth of cutting and width of cutting in 3 levels to obtain the influence degree of cutting parameters on cutting force, specific energy consumption, and the surface roughness. The energy efficiency of 27 group experiments is classified into high, medium and low levels according to energy efficiency value. Finally, using the data of orthogonal test, energy efficiency state was identified. The result show that time–frequency of cutting force signals for high, medium and low energy efficiency could be extracted, and the average absolute error of surface roughness predict is 0.058. That illustrated that the proposed method could meet the industry requirement for energy efficiency monitoring and surface roughness prediction to achieve sustainable manufacturing.

Recyclable thermo-responsive elastin-based adhesives with tough underwater adhesion and rapid hemostasis ability

Protein-based underwater adhesives have attracted tremendous attention due to their excellent biocompatibility compared to adhesives prepared with synthetic polymers. However, the fabrication of protein-based adhesives always requires multiple successive steps, and their underwater adhesion is quite limited. Inspired by the human elastic fibers, bone matrix, and marine adhesive proteins, a thermo-responsive underwater adhesive was fabricated through a facial one-step complexation of elastin (ELN), hydroxyapatite (HAP), and tannic acid (TA) based on multiple non-covalent molecular interactions. During underwater adhesion, the adhesive can perform sufficient flowability to adhere seamlessly and strongly to the substrates upon heating at 37 ℃ and then significantly increase its cohesion through cooling down to 25 ℃ to sustain adhesion. The regulation of the balance between adhesion and cohesion in response to temperature change enables the adhesive to exhibit a robust underwater adhesion ranging from 0.3 to 1.1 MPa to the substrates with low, medium, or high surface energy, outperforming most protein-based adhesives. Importantly, the adhesive can be further processed into powders with well-maintained underwater adhesion by a simple drying and grinding method, facilitating adhesion onto irregular-shaped target sites, reusability, and closed-loop recycling. The adhesive powder also possesses a rapid in vivo hemostatic property, suggesting a potential biomedical application.

Revisiting the dead time effects of Insight-HXMT/ME on timing analysis

ABSTRACT Dead time is a common instrumental effect of X-ray detectors, which would alter the behaviour of timing properties of astronomical signals, such as distorting the shape of power density spectra (PDS), affecting the root-mean-square of potential quasi-periodic oscillation signals, etc. We revisit the effects of the dead time of Medium Energy X-ray telescope (ME) onboard Insight-HXMT based on the simulation of electronic read-out mechanism that causes the dead time and the real data. We investigate dead time effects on the pulse profile as well as the quasi–periodic oscillation (QPO) signals. The dead time coefficient suggests a linear correlation with the observed count rate in each phase bin of the pulse profile according to the simulation of periodic signal as well as the real data observed on Swift J0243.6+6124. The Fourier-amplitude-difference (FAD) method could well recover the intrinsic shape of the observed PDS in the case that the PDS is from two identical detectors. We apply this technique on ME, by splitting the nine FPGA modules into two groups. The results indicate that the FAD technique suits the case when two groups of detectors are not largely different; and the recovered PDS of Sco X-1 observed by ME slightly enhances the significance of the previously known QPO signal, meanwhile the root-mean-square of QPO is significantly improved. We provide the FAD correction tool implemented in HXMTDAS for users in the future to better analyse QPO signals.