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The ultrafine cellular structure promotes the extraordinary mechanical performance of metals manufactured by laser powder‐bed‐fusion (L‐PBF). An in‐depth understanding of the mechanisms governing the thermal stability of such structures is crucial for designing reliable L‐PBF components for high‐temperature applications. Here, characterizations and 3D discrete dislocation dynamics simulations are performed to comprehensively understand the evolution of cellular structures in 316L stainless steel during annealing. The dominance of screw‐type dislocation dipoles in the dislocation cells is reported. However, the majority of dislocations in sub‐grain boundaries (SGBs) are geometrically necessary dislocations (GNDs) with varying types. The disparity in dislocation types can be attributed to the variation in local stacking fault energy (SFE) arising from chemical heterogeneity. The presence of screw‐type dislocations facilitates the unpinning of dislocations from dislocation cells/SGBs, resulting in a high dislocation mobility. In contrast, the migration of SGBs with dominating edge‐type GNDs requires collaborative motion of dislocations, leading to a sluggish migration rate and an enhanced thermal stability. This work emphasizes the significant role of dislocation type in the thermal stability of cellular structures. Furthermore, it sheds light on how to locally tune dislocation structures with desired dislocation types by adjusting local chemistry‐dependent SFE and heat treatment. [ABSTRACT FROM AUTHOR]

The dynamic behavior of nonmetallic inclusions at the bubble–steel interface is a key factor contributing to the formation of large‐sized inclusions or clustered particles and is particularly important for the production of high‐quality‐oriented silicon steel. In this study, high‐temperature confocal laser scanning microscopy is employed for in situ observation of the agglomeration behavior of Al2O3 inclusions of varying sizes. The critical distance of attraction decreases with the decrease in inclusion size. The effects of particle size, distance, surface tension, density, and different types of inclusions on the capillary force are explored in detail using the Kralchevsky–Paunov model. In the model results, it is highlighted that the degree of influence among the factors affecting the capillary force decreases in the following order: contact angle > size > distance > density > surface tension. Furthermore, the observed results are compared with the model calculation results. The trends of the model calculations and the experimental results show good agreement, but most of the experimental values are higher than the theoretical values. The errors primarily stem from inclusion shape, interference from other inclusion forces, and interactions between the crucible wall and inclusions. [ABSTRACT FROM AUTHOR]

Herein, a 3D stability diagram is established in the AlON system. Based on that, four sets of experiments with different Al contents are designed to prepare different inclusions. Subsequently, the agglomeration behavior of inclusion is observed in situ by using confocal laser scanning microscopy (CLSM) combined with an infrared image furnace. The sample with inclusions is heated to melt and the agglomeration behavior of inclusion is recorded by the CRT monitor of CLSM. The calculated agglomeration force of inclusion shows that when the Al content increases from 0.5 to 3 pct, the agglomeration force of Al2O3 inclusions decreases from 7.2 × 10−16 ≈ 6.0 × 10−14 N to 1.2 × 10−16 ≈ 3.2 × 10−15 N. As the Al content increases from 6.5 to 10 pct, the agglomeration force of AlN inclusions increases from 2.2 × 10−17 ≈ 1.1 × 10−15 N to 1.7 × 10−16 ≈ 7.9 × 10−15 N. The theoretical calculation also shows that the agglomeration force of Al2O3 inclusions decreases and that of AlN inclusions increases with the increasing Al content. When the Al content is >4.7 pct, the agglomeration force of AlN inclusions is larger than that of Al2O3 inclusions. [ABSTRACT FROM AUTHOR]

Castor oil has attracted large attention for wide applications, including lubrication oil and bioenergy resources. Castor seeds mechanical pressing is widely used for oil extraction. To better research castor seeds mechanical‐structural damage behavior and oil extraction mechanism during extrusion, a self‐developed mechanical pressing test setup combined with in situ observation is built for oil output behavior. Influencing factors of working pressure, speed, temperature and creep time on oil outflow were investigated. The results indicate that seeds squeezing extraction can be divided into three stages, preloading, oil discharging, compressing consolidation stage, matching with pressing cake structural evolution. As working pressure increases, oil yield shows an upper parabola relation with pressure. When pressure exceeding 25 MPa, castor oil yield increasing tends to stabilize, reaching 38%. Speed effect showed down parabola relation on oil yield, opposite to stress factor. Creep time promoted oil output with upper parabola within 720 s. When temperature below 120°C, a linear increasing relation on oil yield presents. Oil yield decreases when above 120°C. This research provides in‐depth theoretical guidance for industrial castor oil extraction. Practical Applications: Castor seeds are rich in oil content. Extracted castor oil has been widely used for industrial applications such as biodiesel, lubricants, medicine. Mechanical extraction working parameters optimization can improve oil yield of castor seeds. The research provides a basic working optimization for castor seeds oil extraction. Castor oil has unique properties and has been proved to be a high promising renewable and independent energy sources. Compared with solvent oil extraction, mechanical oil pressing extraction method has higher oil quality and safety. The mechanical extracted oil is pure without organic solvent. In the research, castor seeds compression‐structural damage property and oil extraction mechanism were studied. Besides, the influence factors including compression pressure, speed, temperature and creep time are analyzed, working optimization for castor seeds oil extraction. The research provides important reference value for the mechanical pressing process and mechanical design of castor seeds in the practical applications. [ABSTRACT FROM AUTHOR]

Atmospheric aerosols not only cause severe haze pollution, but also affect climate through changes in cloud properties. However, during the haze pollution, aerosol‐cloud interactions are not well understood due to a lack of in situ observations. In this study, we conducted simultaneous observations of cloud droplet and particle number size distribution, together with supporting atmospheric parameters, from ground to cloud base in East China using a high‐payload tethered airship. We found that high concentrations of aerosols and cloud condensation nuclei were constrained below cloud, leading to the pronounced "Twomey effect" near the cloud base. The cloud inhibited the pollutants dispersion by reducing surface heat flux and thus deteriorated the near‐surface haze pollution. Satellite retrievals matched well with the in situ observations for low stratus clouds, while were insufficient to quantify aerosol‐cloud interactions for other cases. Our results highlight the importance to combine in situ vertical and satellite observations to quantify the aerosol‐cloud interactions. Plain Language Summary: Atmospheric aerosols, one of the major pollutants contributing to air pollution, also play an important role in climate through their interactions with clouds. The impact of aerosols on cloud properties remains the largest uncertainty in climate projections, partly due to a lack of in situ observations. Here, we conducted simultaneous observations on atmospheric aerosols and clouds from ground to 1,200 m above ground level in East China using a high‐payload tethered airship. We found aerosols number concentration was high below the clouds, which increased the cloud droplet concentration and decreased the cloud droplet diameter near cloud base. The clouds deteriorated the near‐surface air pollution, thus increasing exposure to hazardous levels. For low stratiform clouds, the satellite retrievals matched well with the observations, suggesting the satellite observation is a powerful tool to investigate clouds. However, the aerosol‐cloud interactions can still be underestimated by satellite measurements as the satellites record cloud properties near cloud top. We emphasize the need for direct in situ observations from the ground to high altitudes to quantify the effects of aerosols on cloud properties. Key Points: The pronounced Twomey effect near the cloud base was directly observed during the haze pollution by the tethered airship measurementThe observed Twomey effect at the cloud base in East China contradicts the satellite‐detected anti‐Twomey effect at the top of cloudsSatellite retrieved cloud effective radius is comparable to observation near cloud base of low stratus clouds, while is biased for others [ABSTRACT FROM AUTHOR]

In‐situ observations of hydrodynamics and suspended sediment concentrations (SSCs) were conducted on an abandoned lobe in the northern part of the modern Yellow River Delta, China. The SSC record at the site is found to be the superposition of a general trend (fast increase and slow decrease cycle) caused by storm waves (SubSSC1) and relatively smaller fluctuations caused by tidal currents (SubSSC2). Physically, this indicates that storm waves eroded the bottom sediments while tidal currents then re‐suspended and advected the suspended sediments in the study area. To further obtain the suspended sediment transport parameters, first, SubSSC1 is modeled with significant wave height which incorporates a "memory curve" to consider the remaining impacts of historical waves. It is detected that waves in the past 75 hr still influence the present SSC which is reasonable because 75 hr is roughly the typical duration of a normal storm. Second, SubSSC2 is modeled with tidal excursion and trigonometric functions with measured periodicities. Finally, some sediment transport parameters, for example, the background SSC, the horizontal SSC gradient, the tidal constituents that advect it, and their relative time lags are optimized from the best fits of the measured and modeled SSC time series. The proposed framework for model construction and parameter optimization can be extended to other sea areas for inferring sediment transport parameters from field SSC time series at a specific station. Plain Language Summary: The evolution of our coastal zone fundamentally depends on the transport volume and direction of sediment, and understanding them is very beneficial for our coastal engineering construction and long‐term planning. Conducting in situ observations on‐site is one of the most reliable methods, but its observation cost is expensive. Therefore, we hope to extract as much information as possible from as few observation points as possible. This article successfully extracted the above information from the observation data of a station. First, we analyzed the data to preliminarily clarify that the suspended sediment in the area mainly comes from local erosion resuspension and advection transport from other regions. Furthermore, we conducted data modeling (i.e., constructed mathematical expressions of suspended sediment components from different sources, but with undetermined coefficients). Finally, we adjusted the model parameters to approximate the measured results, determined the undetermined coefficients, and explained the practical significance of the undetermined coefficients in physics. The analysis method we proposed can be extended to other sea areas. Key Points: Storm wave‐induced suspended sediment concentration (SSC) variation is modeled with a "memory curve" of wave heightTidally‐induced SSC variation is modeled with tidal excursion and trigonometric functionsSediment transport parameters are estimated from the optimal matching of measured and modeled SSC time series [ABSTRACT FROM AUTHOR]

Air‐sea exchanges across oceanic fronts are critical in powering cloud formation, precipitation, and atmospheric storms. Oceanic submesoscale fronts of scales 1–10 km are characterized by strong sea surface temperature (SST) gradients. However, it remains elusive how submesoscale fronts affect the overlying atmosphere due to a lack of high‐resolution observations or models. Based on rare high‐resolution in situ observations in the Kuroshio Extension region, we quantify the air‐sea exchanges across an oceanic submesoscale front. The cross‐front SST and turbulent heat flux gradients reaches 2.4°C/km and 47 W/m2/km, respectively, far stronger than that typically found in mesoscale‐resolving products. The stronger SST gradient drives substantially stronger air‐sea fluxes and vertical mixing than mesoscale fronts, enhancing cloud formations. The intense air‐sea exchanges across submesoscale fronts are confirmed in idealized model simulations, but not resolved in mesoscale‐resolving climate models. Our finding provides essential knowledge for improving simulations of cloud formation, precipitation, and storms in climate models. Plain Language Summary: Oceanic fronts, characterized by large sea surface temperature (SST) gradients, are ubiquitous in the global ocean. Through intense heat and moisture release, these oceanic fronts induce large horizontal gradient of sea level pressure or increasing vertical mixing intensity in the lower atmosphere, are critical in powering cloud formation, precipitation, and atmospheric storms, but are sensitive to SST gradients. Oceanic submesoscale fronts of spatial scales 1–10 km are characterized by strong SST gradients. However, our knowledge of how the submesoscale fronts affect the overlying atmosphere is by and large void, due to a lack of high‐resolution observations or models. Here, based on high‐resolution in situ observations and model simulations, we show that submesoscale fronts drive much stronger air‐sea exchanges and vertical mixing as compared to mesoscale fronts, with significant implications for marine atmosphere boundary layer changes and cloud formations. Limited by the coarse resolution, the intense air‐sea exchanges across submesoscale fronts are not resolved in mesoscale‐resolving climate models. These results highlight the importance of submesoscale air‐sea interactions and call for a proper representation of submesoscale air‐sea exchanges in the next generation of climate models. Key Points: Observations show strong gradient in sea surface temperature and turbulent heat flux across a submesoscale oceanic frontSubmesoscale fronts drive substantially stronger air‐sea fluxes and vertical mixing than mesoscale frontsThe intense air‐sea exchanges across submesoscale fronts are not resolved in mesoscale‐resolving climate models [ABSTRACT FROM AUTHOR]

Using the Arase and Van Allen Probes satellite observations, we investigate the nonlinear electromagnetic ion cyclotron (EMIC) rising‐tone (RT) emissions with an increase of the solar wind dynamic pressure in the dayside magnetosphere. We find that EMIC RT emissions are accompanied by the extended dayside uniform zone (DUZ) over |MLAT| < 25° due to the dayside magnetospheric compression by an increase in Pdyn. Using the observed plasma and magnetic field data, we modeled the threshold amplitude for the nonlinear EMIC waves and compared it with the observation. The small gradient of the ambient magnetic field strongly contributes to the reduction in the threshold amplitude of nonlinear wave growth compared to other parameters. When the threshold amplitude falls to comparable level of pre‐existing EMIC waves, EMIC RT emissions are immediately triggered, suggesting direct evidence that the DUZ is the preferred condition to cause the nonlinear EMIC RT emission in the dayside magnetosphere. Plain Language Summary: Electromagnetic ion cyclotron (EMIC) waves play an important role in controlling the dynamics of charged particles in the inner magnetosphere. Especially, nonlinear EMIC rising‐tone (RT) emissions can cause the rapid loss of relativistic electrons and ring current ions. Here, we present direct evidence demonstrating that the distortion of the dayside magnetic field causes nonlinear EMIC RT emission in response to the intensification of the solar wind dynamic pressure. Remarkably, these nonlinear EMIC waves are generated through a reduction in the threshold wave amplitudes by the distortion of the magnetic fields, even in the absence of any significant change in the pre‐existing EMIC wave amplitude. The present result provides new insights into a triggering process of nonlinear plasma waves in the magnetosphere. Key Points: Electromagnetic ion cyclotron (EMIC) waves with rising‐tone (RT) elements were observed in the dayside magnetosphere during an increase in the solar wind dynamic pressureIncreasing solar wind dynamic pressure extends the dayside uniform zone of the magnetic field to higher magnetic latitudesThe uniform zone leads to the reduction of the nonlinear threshold wave amplitude, which triggers nonlinear EMIC RT emissions [ABSTRACT FROM AUTHOR]

Although evolution dynamic investigation onto electrochemically generated bubbles on electrode surfaces is crucial for releasing "bubble blocking" effects, traditional "top view" or "side view" methods make spatiotemporal interfacial revolutions difficult to achieve, which are critical for a deeper understanding and better electrode design. In this study, a novel method utilizing surface plasmon resonance (SPR) is proposed to probe bubble interfacial dynamics. By monitoring reflectivity changes and utilizing differential imaging, real‐time fluctuations in the contact area can be accurately visualized. The investigation onto bubble growth events on both aerophilic and aerophobic surfaces reveals that they occur in very distinct patterns. Due to the "necking effect", the reflectivity of aerophilic electrodes rushed to its highest value and remained or gradually decreased, followed by a sudden drop due to bubble disengagement. While the aerophobic ones increased to the bubble release threshold after a downward parabola function, then dropped abruptly without plateau. This in situ imaging technique provides a feasible tool for bubble disengagement dynamic investigations on electrode surface. Based on current observations, it is revealed that changing the wettability of electrodes causes substantial changes in bubble evolution dynamics. [ABSTRACT FROM AUTHOR]

Wave and water depth were measured with an instrumented tripod in the Yellow River Delta from 9 December 2014 to 29 April 2015. Concurrent wind data were also collected from a nearby wind station. A high‐precision model for predicting local significant wave height (Hs) with wind speed (vw) is constructed using an improved data‐driven approach. The proposed model realized high accuracy as it solves the problem that the Hs falls too fast during the wind‐decreasing periods. It was tackled by considering the remaining influence of historical vw on the present Hs via incorporating a memory curve of the past wind effect. This innovative approach significantly improves the prediction (R2 from 0.60 to 0.83). The winds in the past 24 hr still left an influence on the waves at the observation site although the influence decreases with time. Physically, it is an implicit but simpler consideration of wind fetch/duration. Further data modeling experiments indicated that the decisive factor for the Hs at the site is the wind speed. Wind directions slightly improve the prediction, indicating that waves are slightly affected by the underwater seabed slope along different wind directions, and northwest winds cause the strongest waves at the site. Adding atmospheric pressure or water depth even reduces the accuracy, which indicated that storm surges and wave deformations under different tide levels have a weak impact on Hs. The proposed local wave model can be easily constructed with available wind and wave data, making it expandable to other regions dominated by wind waves. Plain Language Summary: Wave conditions in the ocean are essential for engineering applications. Due to the influence of geographical environment, topography, and geomorphology, the wave conditions of a certain station in the ocean often have certain rules to follow. This paper attempts to establish a high‐precision prediction model for local significant wave height of wind waves through long‐term in situ observations and machine learning methods. The introduction of a "memory curve" into the conventional Support Vector Regression model significantly improved the prediction accuracy. The physical meaning of the "memory curve" corresponds to the residual impact of historical wind speed, which is the implicit expression of the effects of wind duration/fetch in wave development. The proposed method can be easily applied to other sea areas dominated by wind waves. Key Points: A high‐accuracy local wind wave height model is built based on wind speedA memory curve is incorporated into Support Vector Regression to improve the prediction significantlyInfluencing factors of wave height are explored through data modeling experiments [ABSTRACT FROM AUTHOR]

This study attempts to propose a convenient method to adjust the welding process parameters window with the aim of high volume fraction of acicular ferrite in the weld metal (WM). The samples are directly extracted from the deposition zone of two low alloy ferritic steel dissimilar welded joints (DWJs) that manufactured using different consumables, and their microstructural evolution is controlled using thermomechanical simulation technique. The results show that it is hard for the low‐alloyed WM to obtain high amount of acicular ferrite no matter how to control the cooling process, meaning that the welding consumable with only a small amount of alloying elements is not suitable for welding this DWJ. However, for the high‐alloyed WM, the acceptable window of the cooling process is determined within 10–22 °C s−1 to achieve aimed microstructure. In situ observation shows that the preexisting bainitic laths significantly reduce the growth space of acicular ferrite plates. The average lengthening rate of acicular ferrite plates is ranged from ≈5 to ≈68 μm s−1 at a cooling rate of 3 °C s−1. [ABSTRACT FROM AUTHOR]

Herein, the crystallographic morphology of the 80%Bi2O3‐20%Fe2O3 pseudo‐binary system under different cooling rates (100, 6.3, 0.12 K s−1) is investigated using an optical microscopy system. The interfacial morphology evolution and interfacial kinetics in two dimensions during crystal growth are systematically studied. At the low cooling rate (ΔT < 10 K), blade‐like crystals appear slowly in the melt. In turn, the emergence of numerous irregularly shaped grains in the melt at the high cooling rate (ΔT > 100 K) indicates a rapid solidification process. Tetragonal crystals appear typically during melt solidification accompanied with triangular crystals simultaneously (15 K < ΔT < 35 K). The X‐ray diffraction and EDS data reveal that both kinds of polygonal crystals are attributed to Bi25FeO40. In addition, the crystal growth kinetics are presented as the dependence of the growth rate on the subcooling, and thus the growth mechanism of crystals is discussed. According to the results, Bi25FeO40 crystals grow through a two‐dimensional nucleation mechanism. [ABSTRACT FROM AUTHOR]

The contribution that fronts and frontogenesis make to subsurface chlorophyll a (CHL) concentration was investigated near the Kuroshio using data from multiple surveys across the Kuroshio during summer and fall and satellite sea surface height (SSH) data alongside high‐resolution reanalysis data set. An intensive survey was conducted during a period of frontogenesis as seen from the in‐situ and satellite‐derived velocity data as well as the analysis of the reanalysis data set. Physical and biological observation showed shoaling of the nitracline and a subsurface CHL maximum (SCM) near the evolving front. The CHL concentration at the SCM (CHLSCM) was large near the front compared with the concentration in ambient water. Sections of 10 repeat seasonal surveys also captured the frontal structure, the shoaling of the nitracline, and the increase in CHLSCM as well as their interrelationship. The CHLSCM was large, and the depth of the SCM (ZSCM) was shallow above a large horizontal density gradient (i.e., marked mesoscale frontal structure) in the ocean interior. In addition, we demonstrate that the lateral strain rate, which is a measure of frontogenesis obtained from the SSH, can be used to estimate ZSCM and CHLSCM. Frontogenesis, secondary circulation, symmetric instability, and vertical diffusion were considered to cause the nutrient supply to the subsurface layer. The surveys and analysis indicate that fronts and frontogenesis increase CHLSCM, and the physical data obtained from both in‐situ and satellite observations can be used to estimate CHL distribution in the ocean interior. Plain Language Summary: The contribution that oceanic front and its strengthening make to subsurface chlorophyll a (CHL) concentration was investigated near the Kuroshio south of Japan using data from multiple surveys and satellite altimetry alongside high‐resolution reanalysis data set. The Kuroshio front strengthened during an intensive survey across the Kuroshio as seen from in‐situ, satellite‐derived and reanalysis velocity data. Physical and biological observations showed nutrient upwelling and increase in subsurface chlorophyll a concentration near the strengthening front. Sections of 10 repeat surveys during summer and fall showed that the depth where the chlorophyll a concentration increased was shallow and the chlorophyll a concentration was large when the front was strong. In addition, we demonstrate that a measure of strengthening of fronts obtained from the satellite‐derived data is valid to estimate the distribution of subsurface chlorophyll a concentration. Key Points: Frontogenesis supplies nutrients and increases subsurface chlorophyll a concentrationChlorophyll a concentration is positively correlated with the strength of fronts and frontogenesisSubsurface chlorophyll a concentration is estimated using satellite‐derived geostrophic velocity [ABSTRACT FROM AUTHOR]

To investigate faster crystallization of zeolite beta by the dry‐gel conversion method, the local structure of the dry gel before synthesis was quantitatively evaluated using in situ Raman spectroscopy during the drying process. The dry gel prepared from Si and Al sources, and tetraethylammonium hydroxide solution was crystallized after several hours by the dry‐gel conversion method. The conformational change of TEA+ cations was observed during the drying process by the deconvolution of the spectrum, and the conformational change was larger than that during the synthesis process. The rate of conformational change was increased with the drying temperature, and the apparent activation energy was estimated to be 68.2 kJ/mol. The generation and transformation of double three‐membered silicate rings (D3Rs) and 4‐2 type secondary building units (SBUs), which are essential for the crystallization of zeolite beta, were observed during the drying process. The transformation from D3R to 4‐2 SBU in the dry gel during drying process could be confirmed quantitatively by the difference of the time variation for the amounts of these silicate building units estimated by in situ observation. [ABSTRACT FROM AUTHOR]

Herein, the void nucleation induced by typical inclusions in low‐density steel is observed using a scanning electron microscope during the in situ tensile deformations, and the void nucleation mechanism is clarified based on the numerical simulation. The dislocation accumulation and stress concentration are observed around single AlN, MnS, AlN–MnS, aggregated AlN, and aggregated AlN–MnS inclusions. The nucleation and development of the void are through the inclusion cracking or inclusion interface debonding. During the tensile process, the cracking of single AlN and debonding of MnS/matrix induce the void nucleation. For AlN–MnS, the debonding of the internal AlN/MnS interface or external MnS/matrix interface can both induce void formation, which is associated with the relative dimensions of AlN and MnS. Aggregated AlN and aggregated AlN–MnS are suggested to be more harmful to low‐density steel. The void nucleation in aggregated AlN and aggregated AlN–MnS is, respectively, owing to the debonding of the AlN/matrix interface or AlN/MnS interface. [ABSTRACT FROM AUTHOR]

Lithium (Li) penetration through solid electrolytes (SEs) induces short circuits in Li solid‐state batteries (SSBs), which is a critical issue that hinders the development of high energy density SSBs. While cracking in ceramic SEs has been often shown to accompany Li penetration, the interplay between Li deposition and cracking remains elusive. Here, we constructed a mesoscale SSB inside a focused ion beam‐scanning electron microscope (FIB‐SEM) for in situ observation of Li deposition‐induced cracking in SEs at nanometer resolution. Our results revealed that Li propagated predominantly along transgranular cracks in a garnet Li6.4La3Zr1.4Ta0.6O12 (LLZTO). Cracks appeared to initiate from the interior of LLZTO beneath the electrode surface and then propagated by curving toward the LLZTO surface. The resulting bowl‐shaped cracks resemble those from hydraulic fracture caused by high fluid pressure on the surface of internal cracks, suggesting that the Li deposition‐induced pressure is the major driving force of crack initiation and propagation. The high pressure generated by Li deposition is further supported by in situ observation of the flow of filled Li between the crack flanks, causing crack widening and propagation. This work unveils the dynamic interplay between Li deposition and cracking in SEs and provides insight into the mitigation of Li dendrite penetration in SSBs. [ABSTRACT FROM AUTHOR]

Solidification end reduction is a novel technique that can effectively refine the microstructure and improve the homogeneity in continuously cast steel. Herein, the static recrystallization (SRX) behaviors and microstructure evolution of microalloyed continuous casting slabs during the heavy reduction (HR) process are simulated and analyzed by means of high‐temperature laser scanning confocal microscopy (HT‐LSCM). According to the statistical results of microstructure, the insulation temperature has a more significant effect on the SRX fraction and recrystallization grain size compared with the strain rate, initial austenite grain size, and prestrain, and a modified SRX kinetic model is proposed. Furthermore, a deforming microstructure is observed at different strains and holding times with electron backscatter diffraction (EBSD), and it is found that the reduction of high‐angle boundaries (HAGBs, θ > 15°) of 25°–35° is related to strain‐induced boundary migration (SIBM). The stored deformation energy of HAGBs is higher than that of very low‐angle boundaries (VLAGBs, θ < 5°) by the detailed misinterpretation profile analysis of the block and lath boundaries. Finally, the combination of in situ observation and EBSD analysis shows that the stored deformation energy provides the driving force for the SRX process, which, in turn, consumes dislocations to stabilize the microstructure. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable zinc–metal batteries are a promising candidate for next‐generation energy storage devices due to their intrinsic high capacity, low cost, and high safety. However, uncontrollable dendrite formation is a serious problem, resulting in limited lifespan and poor coulombic efficiency of zinc–metal anodes. To address these issues, a 3D porous hollow fiber scaffold with well‐dispersed TiO2, SiO2, and carbon is used as superzincophilic host materials for zinc anodes. The amorphous TiO2 and SiO2 allow for controllable nucleation and deposition of metal Zn inside the porous hollow fiber even at ultrahigh current densities. Furthermore, the as‐fabricated interconnected conductive hollow SiO2 and TiO2 fiber (HSTF) possess high porosity, high conductivity, and fast ion transport. Meanwhile, the HSTF exhibits remarkable mechanical strength to sustain massive Zn loading during repeated cycles of plating/stripping. The HSTF with interconnected conductive network can build a uniform electric field, redistributing the Zn2+ ion flux and resulting in smooth and stable Zn deposition. As a result, in symmetrical cells, the Zn@HSTF electrode delivers a long cycle life of over 2000 cycles at 20 mA cm−2 with low overpotential (≈160 mV). The excellent cycling lifespan and low polarization are also realized in Zn@HSTF//MnO2 full cells. [ABSTRACT FROM AUTHOR]

On September 1, 2015, an Mw 5.9 interplate earthquake occurred near the Bonin Trench. An array of in situ ocean‐bottom absolute pressure gauges (APGs) observed its tsunami generation field consisting of static and dynamic pressure changes due to tsunami and crustal deformation and due to seismic motion, respectively, under much higher station density than ever reported. We propose an approach to synthesize the pressure change inside the focal area, which reproduces the APG waveforms well. We further successfully estimate the finite fault model of the earthquake and constrain the rupture duration only from the APG data. The relatively low stress drop and seismic wave radiation from the fault model may suggest the nature of a tsunami earthquake. The in situ APGs have a large potential to reveal the broadband source process of the earthquake, which is essential to understand the seismotectonics in the subduction zone. Plain Language Summary: Absolute pressure gauges (APGs) installed on the seafloor have been widely used to observe various phenomena such as tsunamis. When an APG is located inside a subseafloor earthquake source region, the tsunami generation field is observed, which includes not only tsunamis but also dynamic pressure changes related to seafloor dynamic motion during the earthquake fault slip. This study analyzed densely distributed APG array data, which contained the tsunami generation field of a magnitude‐5.9 earthquake that happened near the Izu‐Bonin Trench on September 1, 2015. This observation was performed by APG stations at higher station density than any data ever reported. This study synthesized this APG array data using the theory for tsunami generation and propagation, and the result explained the data dramatically well. This indicates the validity of the tsunami generation theory for actual observation inside the earthquake source area. We also estimated the slip distribution across the fault of this earthquake, which could not previously be obtained. Our results indicate the combination of APG data obtained inside the focal area and the theory for tsunami generation and propagation is useful for extracting the detailed information on the earthquake rupture process. Key Points: We examined pressure changes inside the source region of the 2015 Bonin Mw 5.9 EQ where long‐period seismic waves overlap with tsunamisA numerical simulation for a fluid‐elastic medium was conducted for the pressure change synthetics above the seafloorAnalyzing both tsunamis and dynamic ground motions enabled us to estimate the stress drop and the rupture duration of the Mw 5.9 event [ABSTRACT FROM AUTHOR]

Te can effectively modify MnS inclusion to improve the anisotropy and machinability of steel. To figure out the mechanism of high‐temperature evolution and formation of inclusions, a high‐temperature confocal laser scanning microscope is used to in situ observe the performance of inclusions. In the steel with 22 ppm Te, Te mainly dissolves in MnS; no MnTe is generated. During the heating process, MnS inclusion remains solid state and no obvious phase change can be observed. In comparison, MnS–MnTe binary inclusion in the steel with 680 ppm Te forms a liquid phase due to the eutectic melting. The further increase of temperature causes the serious evaporation of Te. Based on scanning electron microscopy and energy‐dispersive spectrometry analysis and in situ observation of inclusions at high temperature, the formation mechanism of inclusions during solidification is proposed. [ABSTRACT FROM AUTHOR]

The degradation behaviors of as‐received and as‐solutionized AZ31 alloys in Hanks' solution are in situ studied by a 3D digital optical microscope. The initiation and extension processes of corrosion are investigated. Long‐time immersion and electrochemical tests are applied to investigate the corrosion mechanism systematically. The corrosion attacks of as‐received and as‐solutionized AZ31 alloy both start from the grain boundaries (with and without the Al8Mn5 phase) while show no preferential propagation, and the scratches also can act as the corrosion starting positions. The Al8Mn5 phase does not show an obvious accelerated effect on the Mg matrix's corrosion, and it also suffers corrosion. Solid solution treatment can enhance the corrosion resistance of AZ31 alloy is primarily due to the reduced dislocation density. Degradation products on as‐received AZ31 alloy are studied, the Al, Zn, and Mn elements degrade as Al2O3, ZnO, and MnO, respectively. [ABSTRACT FROM AUTHOR]

Drought is one of the most frequent natural disasters occurring in Pakistan and has a great influence on livelihood, agriculture, and economy. The availability of long‐term high‐quality reanalysis products over Pakistan has been of great concern in recent decades. Here, we conduct drought assessment in Pakistan based on the standardized precipitation index (SPI) and the standardized precipitation evapotranspiration index (SPEI) at 3, 6, and 12 months timescales during 1983–2018. We use long‐term in situ observations to evaluate the accuracy of reanalysis products, including Climatic Research Unit (CRU TS), National Centers for Environmental Prediction version II (NCEP‐2), European Centre for Medium‐Range Weather Forecasts Version‐5 (ERA‐5), and Modern‐Era Retrospective analysis for Research and Applications version II (MERRA‐2). The main results are summarized as follows: (a) drought indices and drought areas assessed from reanalysis products are relatively more representative of historical droughts that had occurred in southern Pakistan and overestimation is evident for drought severity in western than eastern Pakistan; (b) statistically significant increasing trends (1984–1998 and 2000–2010) in monthly drought areas and occurrence are evident by CRU TS and MERRA‐2 in dominant arid and semiarid regions; (c) climate variables and drought features of southern Pakistan are best represented by CRU TS and MERRA‐2, while that of southwestern and western parts are best represented by ERA‐5; (d) the Nash–Sutcliffe efficiency (NSE) results range from −2 to 1, where the NSE of SPEI values (−1.0) show relatively weaker than SPI values (0.5) in most parts of the regions, specifically in the southern Pakistan; (e) a strong positive linear relationship on a monthly scale is evident in CRU TS, MERRA‐2, and ERA‐5 exhibiting relatively high correlation coefficient (0.84), except for NCEP‐2. Furthermore, the SPEI results are found to be better than SPI; thus, this study suggests SPEI may be more suitable than SPI in monitoring droughts under climate change. [ABSTRACT FROM AUTHOR]

Micro‐speckle patterns were fabricated using α‐Al2O3 and SiC micro‐particles for in‐plane strain distribution measurement at temperatures up to 1500°C using an ultraviolet high‐temperature observation system (UV‐HTOS) combined with a digital image correlation (DIC) technique. The experimental results showed that the measured mean surface strains of α‐Al2O3 were in good agreement with the calculated values obtained from thermal expansion coefficient and temperature difference. The proposed speckle pattern could be used for strain distribution measurement without degradation even after heating up to 1500°C. The results also demonstrated that the pattern fabricated in this study is effective to understand the heterogeneous deformation mechanism in composite materials applied in high‐temperature structural components. [ABSTRACT FROM AUTHOR]

Despite the high energy density of Ni‐rich layered‐oxide electrodes, their real‐world implementation in batteries is hindered by the substantial voltage decay on cycling, which mainly originates from bulk and surface structural degradation. Here, in operando observation of cation disorder, a major origin of structural degradation, reveals the voltage decay mechanism in Ni‐rich cathode. Viewed along [1 1–0] and [110] orientations by scanning transmission electron microscopy, it is demonstrated that transition metal (TM) migration gives rise to the drastic fluctuation of interlamellar spacing and NiO bond length, but almost exerts no influence on atom site in ab plane. Density functional theory calculations reveal that the fluctuation of the NiO bond length triggers voltage decay via lifting the energy level of the antibonding (3dz2‐2p)* orbits. Broadening bands by a shorter NiO bond increase the voltage slope of battery, which will reduce the accessible Li capacity within the stable voltage range of the electrolyte. Furthermore, a collaborative path of TM migration triggered by oxygen vacancy is verified to account for the TM migration. The finding provides insights into new chemistry to be explored for developing high‐capacity layered electrodes that evade voltage decay. [ABSTRACT FROM AUTHOR]

The transfer of biological concepts into synthetic micropatterned adhesives has recently enabled a new generation of switchable, reversible handling devices. Over the last two decades, many design principles have been explored that helped to understand the underlying mechanics and to optimize such adhesives for certain applications. An aspect that has been overlooked so far is the influence of longer hold times on the adhesive contacts. Exemplarily, the pull‐off stress and work of separation of a micropatterned adhesive specimen are enhanced by factors 3 and 6, respectively, after 1000 min in contact with a glass substrate. In addition to such global measures, the increase of adhesion of all individual micropillars is analyzed. It is found that contact aging varied across the microarray, as it drastically depends on local conditions. Despite great differences on the micropillar scale, the adhesion of entire specimens increased with very similar power laws, as this is determined by the mean contact ageing of the individual structures. Overall, contact aging must be critically evaluated before using micropatterned adhesives, especially for long‐term fixations and material combinations that are chemically attractive to each other. [ABSTRACT FROM AUTHOR]

We examined the catalytic behavior of platinum nanoparticles supported directly on a multi-walled carbon nanotube with environmental scanning transmission electron microscopy. The catalytic etching behavior of the platinum nanoparticles toward the carbon nanotube was found to depend on the oxygen gas pressure. We supposed that direction of catalytic etching could be involved with amount of adsorbed oxygen onto catalytic nanoparticles. In situ observations give new insight of morphological control of carbon nanotube etched by catalytic nanoparticles. [ABSTRACT FROM AUTHOR]

The correlation between molecular interaction and traction properties was investigated using a traction tester and in situ observation of elastohydrodynamic lubrication film with a micro-Fourier transform infrared spectrometer. The sample oils used were polypropylene glycols (PPGs) with the end-group of alcohol or ether and a synthetic hydrocarbon oil, poly-α-olefin. From the traction tests, it was found that the traction coefficient of PPG was sensitive to the end-group. PPG with alcohol as the end-group showed a higher traction coefficient than that with the ether group. In situ observation with a micro-Fourier transform infrared was performed in order to investigate the molecular interaction of the lubricant oil. It was found that the hydrogen bonding of hydroxyl groups in PPG was strengthened by high pressure in the Hertzian contact region. These results suggest that the rheological properties in the elastohydrodynamic lubrication contact region were affected by the strengthened hydrogen bonding. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The interaction between deformation-induced and thermal martensite during tensile deformation in high-manganese transformation induced plasticity steel was studied through in situ observation and electron backscattering diffraction. The specimen, which was composed of metastable austenite, ε-martensite, and α'-martensite, was uniaxially stretched at room temperature at a rate of 0.1mmmin-1 by using a scanning electron microscope installed with an in situ deformation stage. The interaction under study was distinctly demonstrated by the formation means of α'-martensite under external stress. The thermal ε-martensite plates could hardly thicken during deformation. Deformation-induced α'-martensite developed in ε-martensite in two means, namely, nucleation in the intersection of two thin ε-martensite plates and direct growth of preexisting thermal α'-martensite on thick ε-martensite plates. Good content consistency was observed between thermal and deformation-induced martensite; this result quantitatively demonstrates the significant interaction between the two. [ABSTRACT FROM AUTHOR]

A 0-3 nanocomposite of CdSe (crystalline nanoparticles) and Cr2Se3 (amorphous matrix) was synthesized via a soft chemical approach and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Particularly the transformation of the 0-3 composite is explored in situ under electron beam irradiation and thermal annealing inside the TEM. In situ electron beam irradiation removed exclusively the CdSe nanoparticles and generated a porous Cr2Se3 matrix with a slightly increased crystallinity. The highly localized beam heating and knock-on effect are attributed to the origin of the in situ irradiation transformation. During the in situ thermal annealing process of the 0-3 nanocomposite CdSe particles are eliminated and crystalline nano- and microparticles of Cr2Se3 are generated. Also the formation of chromium enriched crystallites is observed. All of these in situ results are compared with conventional ex situ methods and discussed in terms of the different mechanisms associated with electron beam interaction and size effects of the nanocomposite. [ABSTRACT FROM AUTHOR]

The formation of fine-grained mixed microstructure of acicular ferrite and bainite in the simulated coarse-grained heated-affected zone was investigated by means of in situ observation and EBSD analysis. Single, multiple, and sympathetic nucleation of acicular ferrite were observed. Acicular ferrite laths or plates were formed prior to bainite and effectively partitioned austenite grains into many smaller and separated regions. The later formed bainite at lower temperature was confined in those smaller regions, thus resulting in the fine-grained mixed microstructures of acicular ferrite and fine bainite plate. [ABSTRACT FROM AUTHOR]

Impurities are omnipresent during crystallization from solution, both in the lab and in natural environments. Unravelling the mechanisms of impurity effects during crystal growth contributes to the general understanding of crystallization processes and our ability to control it. One way of obtaining information on the impurity mechanisms is to observe the interaction of these foreign species with the growth sites in situ, if possible at a molecular level. At present several optical based techniques are being employed for this type of research. In this chapter, the application of two popular methods in the area of crystal growth observation, atomic force microscopy and confocal microscopy, will be discussed, pointing out the strong points of each technique illustrated with examples from literature and the authors own work. The aim of this chapter is to show experimentalists, venturing into the field of crystal growth, the wide array of research possibilities these techniques offer for exploring the intriguing world of impurity interactions with crystalline materials. [ABSTRACT FROM AUTHOR]

Previous studies on the allotropic transformation in iron suggested a high transformation temperature and a controversial transformation mechanism. At present, however, our understanding of the transformation characteristics in iron seems insufficient, especially as there is a general lack of in situ data on morphological evolution and lattice parameter changes during the transformation. In this study, the characteristics of the morphology, the crystallographic relationships, and short-range diffusion in the allotropic transformation are investigated systematically on the basis of in situ and ex situ observations using time resolved X-ray diffraction, laser scanning confocal microscopy, and electron backscattering diffraction. In contrast to the martensitic transformation, the characteristics of the allotropic transformation will be highlighted. Finally, the results are compared with previous reports in order to provide further insight into the nature of the phase transformation based on the in situ observations. [ABSTRACT FROM AUTHOR]

In Situ ellipsometric study has been carried out during the deposition of the CuInSe2 thin film by means of the three-stage process. A rotator analyzing ellipsomerter using a 632.8 nm He-Ne laser was used. Ellipsometric parameters (Ψ and Δ) and reflectivity R was obtained during the entire deposition stages, in which a complex reflection coefficient is ρ=tanΨ exp(iΔ). Cu, In and Se were deposited on the Mo-coated SLG substrate. At the first-stage (In-Se deposition), the In-Se film deposition rate and its reflactive index has been obtained on the basis of the light interference. At the second-stage, changes in both Ψ and Δ are observed. Based on the X-ray diffraction measurement, these changes are related to the stoichiometric composition of the film from In-rich to Cu-rich. This signal was utilized as a process switch from the second-stage to the third-stage. At the third stage, the weak change in Ψ has been observed showing the change of the stoichiometric composition from the Cu- rich to the In-rich. By means of the in situ ellipsometry-controlled three-stage process, the CuInSe2 layer with single phase chalcopyrite structure has successfully been prepared, which exhibits an intense near-band-edge photoluminescence at 0.998 eV at room temperature. The preliminary fabricated ZnO/CdS/CuInSe2 solar cell exhibited a conversion efficiency of 5.6%. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Grain boundary engineering has been proposed to increase the lifetime performance of sensitized austenitic stainless steel in aggressive environments. Increased microstructure resistance is typically associated with higher fractions of twin (Σ3) grain boundaries, but there is uncertainty about the properties and role of other boundaries. To develop predictive models for stress corrosion crack nucleation, more information is required about how grain boundary crystallography and the orientations of the grain boundary plane and its surrounding grains affect crack development. Digital image correlation combined with electron backscatter diffraction has been used to characterize the microstructure and to observe, in situ, the nucleation and propagation of short stress corrosion cracks in thermo-mechanically processed type 304 stainless steel. The crack path and its growth rate have been determined and are found to be influenced by the microstructure. [ABSTRACT FROM AUTHOR]

In situ atomic force microscope (AFM) imaging of the fatigue and stress corrosion (SC) crack in a high-strength stainless steel was performed, under both static and dynamic loading. The AFM systems used were (1) a newly developed AFM-based system for analysing the nanoscopic topographies of environmentally induced damage under dynamic loads in a controlled environment and (2) an AFM system having a large sample stage together with a static in-plane loading device. By using these systems, in situ serial clear AFM images of an environmentally induced crack under loading could be obtained in a controlled environment, such as in dry air for the fatigue and in an aqueous solution for the stress corrosion cracking (SCC). The intergranular static SC crack at the free corrosion had a sharp crack tip when it grew straight along a grain boundary. The in situ AFM observations showed that the fatigue crack grew in a steady manner on the order of sub-micrometre. The same result was obtained for the static SC crack under the free corrosion, growing straight along a grain boundary. In these cases, the crack tip opening displacement (CTOD) remained constant. However, as the static SC crack was approaching a triple grain junction, the growth rate became smaller, the CTOD value increased and the hollow ahead of the crack tip became larger. After the crack passed through the triple grain junction, it grew faster with a lower CTOD value; the changes in the CTOD value agreed with those of the crack growth rate. At the cathodic potential, the static SC crack grew in a zigzag path and in an unsteady manner, showing crack growth acceleration and retardation. This unsteady crack growth was considered to be due to the changes in the local hydrogen content near the crack tip. The changes in the CTOD value also agreed with those of the crack growth rate. The CTOD value in the corrosive environment was influenced by the microstructure of the material and the local hydrogen content, showing a larger scatter band, whereas the CTOD value of the fatigue crack in dry air was determined by the applied stress intensity factor, with a smaller scatter band. In addition, the CTOD value in the corrosive environment under both static and dynamic loading was smaller than that of the fatigue crack; the environmentally induced crack had a sharper crack tip than the fatigue crack in dry air. [ABSTRACT FROM AUTHOR]

The performance of a new directional solidification device dedicated to the characterization of solid–liquid interface morphology by means of optical methods is presented in this paper. In contradiction to usual solidification studies on transparent materials carried out on thin films, which eliminates the complex coupling between solidification and convection, this device enables in situ and real time studies on bulk transparent materials. The alloy is contained in a cylindrical crucible and observation is performed in two perpendicular directions: the growth one and the transverse one. In addition to direct observation by light transmission in those directions, an interferometer is also set up in the growth direction to provide information on the shape and the motion of the interface through an analysis of the interferometer fringes. The combined determination of solidification front characteristics by these three observation modes has already given critical information on interface dynamics: front recoil measurements during initial transient, formation of microstructure patterns, and influence of convection on the triggering of instabilities. [ABSTRACT FROM AUTHOR]

Contact Aging: Contact Aging Enhances Adhesion of Micropatterned Silicone Adhesives to Glass Substrates (Adv. Funct. Keywords: contact aging; in situ observation; micropatterned adhesion; multiscale experiments; silicone EN contact aging in situ observation micropatterned adhesion multiscale experiments silicone 1 1 1 12/10/20 20201208 NES 201208 Micropatterned silicone adhesives provide a new solution for gripping smooth objects. In article number 2005826, René Hensel and Jonathan Thiemecke investigate how such adhesives adhere to glass substrates over time. [Extracted from the article]

Measuring the lattice parameters of crystalline materials under an electric field at the nanoscale improves the understanding of how electronics operate. Herein, atomic‐scale in situ electron microscopy is used to measure the lattice parameters near the surface of barium titanate under an electric field, which is varied to understand how it changes the lattice parameters. Applying an electric field along the a axis does not cause domain switching. Instead, as the electric field increases, so as well does the c‐axis lattice parameter (c), whereas the a‐axis lattice parameter (a) remains nearly constant. The c value increases as much as 4.5 − 7.0 pm at ±13.8 kV cm−1, which is beyond the measurement precision. The increases are localized near the surface and the c value recovers slowly, which suggests that the observed phenomena are related to surface effects and slow processes. These results cannot be explained by electrostrain, even when considering additional effects such as mechanical constraint, inclination of electric field, and surface and size effects. Instead, the results are explained using a combination of Joule heating, vacancy introduction, and surface effects. [ABSTRACT FROM AUTHOR]

The particles and microstructural characteristics in the simulated heat‐affected zone (HAZ) of the Al–Ti deoxidized steel with 0.05% Ce treatment are investigated using in situ, optical, and electron microscopes and an electron backscattered diffraction analysis, and compared with the Al–Ti deoxidized steel with Ca treatment. The results reveal that the fine CeAlO3 inclusions and nanoscale (Ti, Nb)N precipitates are formed in the Ce‐bearing steel instead of the Ca–Al oxides surrounded by TiN and nanoscale (Ti, Nb)N precipitates in the Ca‐bearing steel. The nanoscale precipitates with higher density in the Ce‐bearing steel can effectively pin austenite grain boundary, and the finer austenite grain is obtained during the welding thermal cycle. The inclusions in both steels are detrimental to the acicular ferrite nucleation. Thus, the transformation from austenite to bainite occurs actively, and bainite packets with different lengthening directions divide the prior austenite into several small regions at intermediate temperature. The fine‐grained microstructure is obtained in the simulated HAZ of the Ce‐bearing steel due to the pinning effect of finer precipitates with higher density and the formation of the bainite packets with high‐angle grain boundary. [ABSTRACT FROM AUTHOR]

Uncovering kinetics of sublimation atomically is critical to understanding both natural phenomena and advanced manufacturing technologies. Here, direct in situ atomic‐scale observations to understand the effects of size, surface, and defects in the sublimation process of supported silver nanoparticles upon heating within an aberration‐corrected transmission electron microscopy are conducted. Atomic‐scale evidence to sublimation and atomic rearrangement in small Ag nanoparticles during heating is provided, and it is demonstrated that the sublimation‐induced stable surfaces in the particles with a size smaller than ≈30 nm are {111} and {100} planes. The role of surface energy and defects in the uniform and nonuniform sublimation pathways at the atomic scale is also revealed, and it is found that the nanoparticles with low surface energy tend to undergo a uniform sublimation pathway, while those with high surface energy or five‐fold twin grain boundary proceed via a nonuniform sublimation pathway. Further dynamic analysis unravels a critical size of ≈8 nm for the transformation from linear to nonlinear sublimation rates in the two pathways. These findings demonstrate that the size, shape, and defects are of paramount importance for the sublimation dynamics in the first‐order phase transformation, helping to advance the general understanding of many technological applications. [ABSTRACT FROM AUTHOR]