High Temperature Environment Research Articles

Prediction method of long-term creep deformation of mobile phone resin lens module in a harsh temp environment

In recent years, the replacement cycle of digital products such as mobile phones in the market has significantly increased, and the accurate prediction of attenuation under long-term usage conditions of the lens module, storage, and other components has become important. The vast majority of mobile phone lens modules are processed from optical resins, and the degradation of their imaging performance is mainly caused by assembly deformation and long-term creep deformation after a high-temperature reliability test. Therefore, there is an urgent need for a reliable model to describe the long-term creep deformation of the mobile phone resin lens module in a harsh temperature environment. This study proposed a modified derivation method for the parameters of the Maxwell constitutive model to predict the long-term creep deformation of the mobile phone resin lens module in a high-temperature environment. The fitting accuracy of the modified generalized Maxwell model and the time-hardening model were compared through uniaxial compression creep experiments. Long-term creep simulations and experiments were conducted on the mobile phone resin lens module; the deformation law of each component of the mobile phone resin lens module was identified; and the creep deformation mechanism was elucidated. The result shows that the modified generalized Maxwell model has much higher accuracy than the time-hardening model in predicting the long-term creep deformation of different resin materials. When considering the influence of the creep phenomenon, the simulation result matches well with the experimental result, and the high-temperature creep mechanism of the mobile phone resin lens module was clarified. In addition, it was found that the maximum deformation of the lens occurred at the lens with the largest size, which was 2.1 µm, and the position with the largest surface deviation was at the edge of the lens. The prediction method proposed in this study can provide guidance and correction suggestions for the structural design of a mobile phone resin lens module and the rationality of optical design; thus, the imaging accuracy of lens modules will be guaranteed to the greatest extent possible.

Comparative study on the compressive performance of NSC and HSC with preload under 24-hour high temperatures

This study explores the compressive performance of normal strength concrete (NSC) and high strength concrete (HSC) with preload under 24-hours sustained high temperature (SHT). A unique test setup was designed to accomplish the compressive tests of concrete under high temperatures. The effects of temperature, concrete strength and preloading are given attention. Besides, microscopic tests were carried out to reveal the variation mechanism of concrete performance. The results show that the degradation of the compressive strength of concrete under SHT is significantly more severe than under short-term high temperatures. At the same temperature and initial load level, HSC shows greater strength degradation than NSC. Pre-loaded concrete generates considerable creep under SHT, and its effect on the peak strain of concrete cannot be ignored. The peak strain of NSC and HSC is most significantly affected by the initial load level and temperature, respectively. At temperatures not higher than 350 °C, the deterioration of the compressive performance of concrete is mainly attributed to the dehydration decomposition of calcium silicate hydrate and the cracking of interface transition zone. Preloading can inhibit these reactions and improve the compressive performance of concrete under SHT. Further, a general model for the compressive stress-strain relationship of concrete under SHT considering concrete strength and preloading was developed, which can be used for the design and analysis of concrete structures serving at high-temperature environments.

Study on energy-saving techniques of the lithium-ion batteries cooling system using a backup battery

The power battery in an electric vehicle is an essential part, and the damage to the battery will have a substantial impact on its thermal characteristics. In order to improve the reliability of the air-cooled lithium-ion battery packs in the high temperature environments, this paper offers a more useful and general optimization strategy for the design of the thermal management system for the batteries which have a damaged battery. To ensure the optimal heat dissipation and prolong the battery string operation, the damaged batteries should be swapped out with the backup batteries. The relationship between the target and the design variables which was established using the quadratic polynomial response function is examined. The experimental cases are selected using the optimal Latin hypercube design approach. After optimizing through the multi-island genetic approach, the error between the simulation results and the prediction results is only 0.06 %. The maximum temperature and the maximum temperature difference of the ideal structure are reduced by 4.58 % and 28.05 %, respectively. Then, the backup battery is selected as the sole battery that has the highest temperature of the ideal structure, and each broken battery is replaced by the backup battery when the damaged position is determined. Finally, a parametric equation connecting the temperature and the flow rate is created, and the inlet flow rate is tuned to match the optimal heat dissipation state of the battery pack. The results of the battery thermal management system having a damaged battery in various situations have an important significance for adjusting the operating conditions of the cooling system for the batteries.

Effect of 60 °C sustained temperature conditions on the mechanical properties and microstructure of alkali-activated fly ash-slag pastes and mortars

The temperature effect has been proven to affect the mechanical properties and microstructure of alkali-activated materials greatly. The research on the long-term complex high-temperature environment for alkali-activated materials remains blank. In this paper, the actual working temperature is selected to study the effects of long-term exposure at 60 °C on the mechanical properties of static/impact load, quality, shrinkage deformation, hydration products, pore structure, and microscopic morphology of alkali-activated fly ash-slag (AAFS). The results show that the mass loss rate of AAFS tends to be stable, the shrinkage deformation rate decreases, and the compressive strength decreases after 28d of sustained high-temperature action. The sustained high temperature causes changes in the hydration product phase, mean chain length (MCL) of the gel phase, pore structure, and micro-morphology. When the duration for 7d and 28d at 60 °C temperature, the compressive strength under static and impact loads increases, which is related to the increase of diffraction peak and MCL of the gel phase; when the duration is 60d and 90d, the compressive strength under static/impact loads decreases, which is related to the increase of cumulative pore volume and the decrease of MCL. Sustained high temperature refines the pore diameter of AAFS samples.

Mechanism of carbide transformation and its impact on the mechanical properties of electron beam freeform fabricated TiC-γ'/Ni-Fe-Cr composite during aging treatment

The inherent instability of the microstructure in nickel matrix composites fabricated via additive manufacturing limits their application in high-temperature environments. This research proposed and prepared a Ni-Fe-Cr matrix composite reinforced with in-situ micron-size TiC and nano-size γ' phases using electron beam freeform fabrication (EBF3) with nickel-based powder-cored wire. To attain a stable microstructure at high temperature, the deposited composite was subjected to aging treatment for different durations. The mechanism of carbide transformation from TiC to Cr23C6 and its influence on the mechanical properties were thoroughly investigated. After aging heat treatment, the γ' particles coarsened from around 10 nm to over 100 nm. TiC phase partially decomposed and transformed into Cr23C6 carbides through the TiC+γ→Cr23C6+γ′ reaction. A distinct Cr23C6/γ'/γ transition layer was formed around the TiC phase. The ideal work of adhesion of the phase interfaces was calculated by first-principles calculations, and the γ' (200)/Cr23C6 (200) interface exhibits the lowest value. With prolonged aging time, the ongoing reaction leads to an increased proportion of mixed carbides, exhibiting a continuous aggregated distribution along grain boundaries. This phenomenon adversely affects the toughness due to weak bonding at the γ'/Cr23C6 interface. As a result, the ultimate tensile strength of the aging treated composites initially increased and then decreased, while the elongation continuously decreased with the extension of aging time.

Honeycomb porous regenerated cellulose aerogel films with enhanced thermal dissipation for agricultural mulch application

Agricultural films, essential to contemporary agricultural production, are mostly made from non-biodegradable petroleum-based materials. The use of such films, especially in high-temperature environments, contributes to elevated internal temperatures in direct sunlight, adversely affecting crop appearance and quality. In this work, rice straw was used as the raw material to prepare biodegradable chemically crosslinked regenerated cellulose aerogel films (RCAF-CC) by combining physical dissolution regeneration, chemical cross-linking, and freeze-drying. The resulting RCAF-CC is notable for its high middle-infrared emissivity and high solar reflectivity, which significantly aid in thermal dissipation for agricultural mulch by enhancing infrared radiation and solar reflection. Compared to traditional polyethylene films, RCAF-CC, with its superior radiative cooling properties and lower water vapor transport rate, has a significant advantage in the growth trend and survival rate of cherry radishes. It is worth noting that the RCAF-CC achieved the degradation rate of 74.4 % in the 100-day soil burial experiment, and the soybean seeds grown in the degraded soil grew well, showing excellent eco-friendliness. These results show that RCAF-CC can be an alternative source of traditional agricultural films, solving the problems of non-biodegradable and high internal temperatures of the films under direct sunlight.

Effect of Titanium Dioxide Particles on the Thermal Stability of Silica Aerogels.

Silica aerogels exhibit a unique nanostructure with low thermal conductivity and low density, making them attractive materials for thermal isolation under extreme conditions. The TiO2 particle is one of the common industrial additives used to reduce the thermal radiation of aerogel composites under high-temperature environments, but its influence on thermal resistance is almost unknown. Herein, we report the effect of TiO2 nanoparticles with different crystal phases and different sizes on the thermal stability of silica aerogel composites. By adding TiO2 nanoparticles, the aerogel can significantly resist collapse at high temperatures (up to 1000 °C). And compared with the rutile phase TiO2, the anatase phase TiO2 shows much higher temperature resistance performance, with shrinkage of only one-sixth of the rutile phase after 800 °C treatment. Interestingly, energy-dispersive spectrometer mapping results show that after 800 °C treatment, silica nanoparticles (NPs) are squeezed out in between anatase TiO2 particles, which resists the coarsening of silica NPs and ultimately enhances the stability of aerogel composites. The optimal anatase phase TiO2-doped silica aerogel demonstrates the integrated properties of crack-free morphology (2.84% shrinkage), low thermal conductivity (29.30 mW/(m·K)) and low density (149.4 mg/cm3) after 800 °C treatment. This study may provide new insights for developing oxide-doped silica aerogels with both high-temperature resistance and low thermal radiation.

The Incorporation of Sulfonated PAF Enhances the Proton Conductivity of Nafion Membranes at High Temperatures.

Nafion membranes are widely used as proton exchange membranes, but their proton conductivity deteriorates in high-temperature environments due to the loss of water molecules. To address this challenge, we propose the utilization of porous aromatic frameworks (PAFs) as a potential solution. PAFs exhibit remarkable characteristics, such as a high specific surface area and porosity, and their porous channels can be post-synthesized. Here, a novel approach was employed to synthesize a PAF material, designated as PAF-45D, which exhibits a specific surface area of 1571.9 m2·g-1 and possesses the added benefits of facile synthesis and a low cost. Subsequently, sulfonation treatment was applied to PAF-45D in order to introduce sulfonic acid groups into its pores, resulting in the formation of PAF-45DS. The successful incorporation of sulfonic groups was confirmed through TG, IR, and EDS analyses. Furthermore, a novel Nafion composite membrane was prepared by incorporating PAF-45DS. The Nyquist plot of the composite membranes demonstrates that the sulfonated PAF-45DS material can enhance the proton conductivity of Nafion membranes at high temperatures. Specifically, under identical film formation conditions, doping with a 4% mass fraction of PAF-45DS, the conductivity of the Nafion composite membrane increased remarkably from 2.25 × 10-3 S·cm-1 to 5.67 × 10-3 S·cm-1, nearly 2.5 times higher. Such promising and cost-effective materials could be envisioned for application in the field of Nafion composite membranes.

Experimental study on the selection of coal-to-oil gasification ash slag gel gelling agent

The gasification ash slag (GAS) is a solid waste that is difficult to degrade and causes serious environmental pollution. In this study, a new type of mine fire prevention and extinguishing gel material was prepared from gasified ash as a base material for spontaneous combustion control of coal in the mining airspace. To better enhance the gel fire prevention process pipeline conveying efficiency, and fire extinguishing performance, the selection of seven gelling agent formulation gasification slag gel, through the thermal stability, water retention, and rheological experiments preferred the best performance of the gelling agent. Thermal stability experiments showed that the thermal decomposition of the gel was divided into three stages: water loss, gel decomposition, and secondary decomposition of decomposition products, and the analysis of the initial decomposition temperature and mass loss rate yielded the best thermal stability of CB-GAS; Water retention experiments show that XG-GAS still retains 72.33 % of water at the 11 h in high-temperature environment, which is the best water retention performance; The rheological experiments showed that the viscosity of the gel decreased continuously with the increase of shear stress, and the analysis of the parameters yielded the best rheological properties of CB-GAS. Combining the four performance indicators, the hierarchical analysis method was used to calculate the influence weight value of the indicators and carry out comprehensive scoring, which resulted in the best performance of the gasification ash fireproofing gel prepared with the optimal gelling agent CB, followed in order by XG, CMC, HPG, MC, SA, and HPMC. This study provides an important reference for gel grouting fireproofing.

Developing a hybrid carbonic anhydrase with exceptional high temperature and alkaline environments resistance for efficient CO2 capture from air

Reducing atmospheric CO2 levels to combat global warming is a pressing concern today. Numerous methods have been employed to capture CO2 from flue gases. One particularly promising approach is the use of carbonic anhydrases (CAs) as biocatalysts for the rapid conversion of CO2 to H2CO3. However, the widespread application of CAs for CO2 capture has been hampered by their inherent instability under real-world conditions. In this study, we have successfully engineered a chimeric carbonic anhydrase with vastly improved physicochemical properties, particularly with respect to its resilience to high temperatures, alkaline pH, and saline environments. Using computational design, we created various hybrid CAs with enhanced resistance to elevated temperatures. Among them, a chimeric CA known as SPS, generated by domain exchange between SazCA and PmCA, exhibited superior heat stability compared to its parent CAs. SPS showed 10 % higher enzymatic activity and retained 80–13 % of its activity during a period of 3 h to 24 h of incubation at 100℃. SPS's apparent kcat and Km values were 4.84 × 108 s−1 and 13.7 mM, respectively. Structural analysis revealed that SPS forms dimers, which contributes to its robustness. Furthermore, we introduced modifications in the form of SPS_1 and SPS_2 variants by incorporating one or two loop sequences from the halotolerant dCAII into SPS. These modifications significantly improved the stability of the CA in alkaline and saline conditions. In particular, SPS showed remarkable efficiency in hydrating CO2 in seawater. Given these compelling results, we propose that hybrid CAs such as SPS, SPS_1, and SPS_2 hold great promise for facilitating CO2 hydration in a wide range of applications. SynopsisGreenhouse gas sequestration is an immediate need. This study reports an engineered and highly stable carbonic anhydrase for CO2 sequestration and greenhouse gas reduction.

Effect of carvacrol on the inhibitory of gas-producing spoilage microbes and volatile flavor in fermented pepper (Capsicum annuum L.)

In this study, two gas-producing spoilage microbes, namely CQ17 and CQ22, were isolated from fermented pepper. Combining the physiological and biochemical characteristics, molecular biological identification, and specific colony morphology, CQ17 was identified as Pichia manshurica while CQ22 was identified as Lentilactobacillus buchneri. Subsequently, our findings indicated that the CQ17 and CQ22 strains exhibited resistance to high temperature, low-pH, and high salinity environments. Meanwhile, our findings revealed that carvacrol, a commonly utilized preservative, exhibited remarkable inhibitory activities against Pichia manshurica and Lentilactobacillus buchneri with the EC50 values of 0.28 and 0.68 mg/L respectively, effectively suppressing the growth of gas-producing strains to prolong the shelf life of fermented pepper. Simultaneously, volatile components of the fermented pepper were analyzed using HS-GC-IMS technology resulting in identification of 55 volatile flavor compounds including acids, alcohols, esters, aldehydes, ketones, alkenes, and other compounds. Among them, (R/S)-linalool, 3-methyl-1-butanol acetate butanoic acid ethyl ester, 2-methyl butanoic acid ethyl ester, and ethyl 2-methylpropionate were identified as crucial components contributing to sensory attributes in fermented pepper as well as (E)-3-hexen-1-ol and l-Pentanol exhibited the highest VIP values and can be considered as the best reliable markers for differentiating fermented pepper samples with the addition of carvacrol as a preservative.

Ultraviolet photon upconversion in Er–SiAlON under 1550 nm excitation

SiAlON ceramics are well known for their exceptional mechanical, thermal, and chemical stability, making them ideal for demanding industrial applications such as cutting tools, equipment for molten metal handling, extrusion molds, gas turbine engines, etc. Despite these applications, the potential for photonic applications such as photon upconversion (UC) in SiAlON ceramics remains less explored. This report demonstrates broad spectral photon UC properties in Er-doped SiAlON (Er–SiAlON) ceramics, covering the ultraviolet (UV) to near-infrared (NIR) range upon 1550 nm excitation. The Er–SiAlON ceramic was synthesized by hot press sintering. X-ray diffraction (XRD), transmission electron microscopy (TEM) and elemental mapping results confirmed the stabilization of the α-SiAlON phase by Er3+ ions. Optical spectra showed distinct transitions of Er³⁺ ions and high transparency of over 70 % in the mid-IR range for the sample thickness of 0.49 mm. Under 1550 nm excitation, UC emission spectra revealed UV, violet, blue, green, red, and NIR emissions. The Er³⁺ ions exhibited self-sensitization, acting both as sensitizers and activators for the UC luminescence. Decay curve analysis showed long excited state lifetimes, with ground state absorption (GSA), excited state absorption (ESA), and energy transfer UC (ETU) processes facilitating multi-photon absorption and diverse spectral emissions. Given the inherent mechanical properties of SiAlON ceramics, these findings highlight the potential of Er–SiAlON ceramics for advanced UC photonic devices operating in high-temperature and harsh environments.

Direct Ink Writing of SiCN/RuO2/TiB2 Composite Ceramic Ink for High-Temperature Thin-Film Sensors.

Direct ink writing (DIW) of high-temperature thin-film sensors holds significant potential for monitoring extreme environments. However, existing high-temperature inks face a trade-off between cost and performance. This study proposes a SiCN/RuO2/TiB2 composite ceramic ink. The added TiB2, after annealing in a high-temperature atmospheric environment, forms B2O3 glass, which synergizes with the SiO2 glass phase formed from the SiCN precursor to effectively encapsulate RuO2 particles. This enhances the film's density and adhesion to the substrate, preventing RuO2 volatilization at high temperatures. Additionally, the high conductivity of TiB2 improves the film's overall conductivity. Test results indicate that the SiCN/RuO2/TiB2 film exhibits high linearity from room temperature to 900 °C, high stability (resistance drift rate of 0.1%/h at 800 °C), and high conductivity (4410 S/m). As a proof of concept, temperature sensors and a heat flux sensor were successfully fabricated on a metallic hemispherical surface. Performance tests in extreme environments using high-power lasers and flame guns verified that the conformal thin-film sensor can accurately measure spherical temperature and heat flux, with a heat flux sensor response time of 53 ms. In conclusion, the SiCN/RuO2/TiB2 composite ceramic ink developed in this study offers a high-performance and cost-effective solution for high-temperature conformal thin-film sensors in extreme environments.

Three-Dimensional Integrated Synaptic Devices Based on a Silver-Cluster Conduction Mechanism with High Thermostability.

During the operation of synaptic devices based on traditional conductive filament (CF) models, the formation and dissolution of CFs are usually uncertain. Moreover, when the device is operated for a long time, the CFs may dissolve due to both the Joule heat generated by the device itself and the thermal coupling between the devices. These problems seriously reduce the reliability and stability of the synaptic device. Here, an artificial synapse device based on polyimide-molybdenum disulfide quantum dot (MoS2 QD) nanocomposites is presented. Research has shown that MoS2 QDs doped into the active layer can effectively induce the reduction of Ag ions into Ag atoms, leading to the formation of Ag clusters and thereby achieving control over the growth of the CFs. Therefore, the device is capable of stably realizing various basic synaptic functions. Moreover, the long-term potentiation/long-term depression (LTP/LTD) of this device shows good linearity. In addition, due to the change in the shape of the CFs, the highly integrated devices with a three-dimensional (3D) stacked structure can operate normally even in a high-temperature environment of 110 °C. Finally, the synaptic characteristics of the devices on learning and inference tests show that their recognition rates are approximately 90.75% (room temperature) and 90.63% (110 °C).

Numerical Development of a Thermal Pre-processing Step for the Recycling of Lithium-Ion Batteries

In the present study, a numerical model is being developed to simulate a step in the battery recycling chain, namely the thermal pre-treatment process. This process involves exposing battery cells to a high-temperature environment to induce a thermal runaway, with the aim of maximising the recovery of valuable metals in the subsequent downstream recycling steps. The proposed numerical model utilises the CFD-DEM framework. Computational Fluid Dynamics (CFD) is used to calculate the gas phase variables. The battery is considered a solid phase, using the Discrete Element Method (DEM) to model its behaviour under high temperature. In this context, an experiment was designed to reproduce conditions similar to a battery thermal deactivation process. Once elaborated, the results from the experiments are compared to the numerical model, seeking further simulations using more realistic furnace designs.

Design and fabrication of metal spherical conformal thin film multisensor for high-temperature environment

Conformal thin-film sensors enable precise monitoring of the operating conditions of components in extreme environments. However, the development of these sensors encounters major challenges, especially in uniformly applying multiple film layers on complex metallic surfaces and accurately capturing diverse operational parameters. This work reports a multi-sensor design and multi-layer additive manufacturing process targeting spherical metallic substrates. The proposed high-temperature dip-coating and self-leveling fabrication process achieves high-temperature thin-film coatings with excellent uniformity, high-temperature electrical insulation, and adhesion properties. The fabricated Ag/Pt thin film thermocouple arrays and a heat flux sensor exhibit a maximum temperature resistance of up to 960 °C, with thermoelectric potential outputs and high-temperature resistance closely mirroring those of wire-based Ag/Pt thermocouples. Harsh environmental testing was conducted using high-power lasers and a flame gun. The results show that the array of thin-film conformal thermocouples more accurately reflected temperature changes at different points on a spherical surface. The heat flux sensors achieve responses within 95 ms and withstand environments with heat fluxes over 1.2 MW/m2. The proposed multi-sensor design and fabrication method offers promising monitoring applications in harsh environments, including aerospace and nuclear power.

Prediction of the Upwarp Buckling Critical Temperature Rise for Longitudinally Connected Slab Track Under Joint Damage State

The joint of longitudinally connected slab track is vulnerable to damage from environmental impacts and repeated train loads. Under high temperature environments, the joint becomes a high risk area for track slab upwarp, which significantly affects the upwarp stability of the track slab and the safe operation of trains. This study employs the arc length approach and a finite element model to investigate the upwarp equilibrium development path of the track slab, the upwarp evolution process of the track slab under the joint damage is further analyzed. Then, the influence of different initial defects on the vertical stability of the track slab is studied. Utilizing dimensional analysis, a general formula for calculating the critical temperature rise of the track slab is proposed. The results are as follows: (1) The entire upwarp process of track slab under joint damage can be divided into three stages: stability, upwarping development, and instability. (2) A nonlinear correlation exists between the upwarp critical temperature rise of the track slab and three types of initial defects. Height defects in narrow joints exert the most significant impact on the critical temperature rise, followed by initial Out-of-straight (initial OOS), with the initial bending shape having the least effect. The complete defect of the narrow joint reduces the upwarp critical temperature rise of the track slab by 53.26°C, a 48.4% reduction. (3) A unified expression, derived from the characteristic parameters of initial defects and dimensional analysis, can more accurately predict the upwarp critical temperature rise of the track slab.

Whole-genome resequencing identifies candidate genes associated with heat adaptation in chickens

The wide distribution and diverse varieties of chickens make them important models for studying genetic adaptation. The aim of this study was to identify genes that alter heat adaptation in commercial chicken breeds by comparing genetic differences between tropical and cold-resistant chickens. We analyzed whole-genome resequencing data of 186 chickens across various regions in Asia, including the following breeds: Bian chickens (B), Dagu chickens (DG), Beijing-You chickens (BY), and Gallus gallus jabouillei from China; Gallus gallus murghi from India; Vietnam native chickens (VN); Thailand native chickens (TN) and Gallus gallus spadiceus from Thailand; and Indonesia native chickens (IN), Gallus gallus gallus, and Gallus gallus bankiva from Indonesia. In total, 5,454,765 SNPs were identified for further analyses. Population genetic structure analysis revealed that each local chicken breed had undergone independent evolution. Additionally, when K = 5, B, BY, and DG chickens shared a common ancestor and exhibited high levels of inbreeding, suggesting that northern cold-resistant chickens are likely the result of artificial selection. In contrast, the runs of homozygosity (ROH) and the ROH-based genomic inbreeding coefficient (FROH) results for IN, TN, and VN chickens showed low levels of inbreeding. Low population differentiation index values indicated low differentiation levels, suggesting low genetic diversity in tropical chickens, implying increased vulnerability to environmental changes, decreased adaptability, and disease resistance. Whole-genome selection sweep analysis revealed 69 candidate genes, including LGR4, G6PC, and NBR1, between tropical and cold-resistant chickens. The genes were further subjected to GO and KEGG enrichment analyses, revealing that most of the genes were primarily enriched in biological synthesis processes, metabolic processes, central nervous system development, ion transmembrane transport, and the Wnt signaling pathway. Our study identified heat adaptation genes and their functions in chickens that primarily affect chickens in high-temperature environments through metabolic pathways. These heat-resistance genes provide a theoretical basis for improving the heat-adaptation capacity of commercial chicken breeds.

Numerical investigation of diamond complementary logic integrated circuits

Silicon complementary metal oxide semiconductor (CMOS) technology drives the integrated circuit industry due to its energy efficiency. The narrow bandgap of silicon has led to the development of wide bandgap semiconductor materials, such as diamond, favored in power electronics, radiofrequency and extreme environment applications. Here we have established a model of the diamond CMOS logic inverter for the first time and successfully simulated the static and dynamic characteristics. The simulated physical model and relevant model parameters are well calibrated with experimental data of diamond p-FET in the literature. The simulation results demonstrate that the all-diamond CMOS inverters possess rail-to-rail operation and excellent inversion characteristics, with the peak gain of 83 V/V, the transition region of 0.25 V, and the noise margins for low and high level of 2.44 V and 2.26 V under VDD = 5 V. Particularly, all-diamond CMOS inverters have improved performance compared to the diamond-GaN inverters, operating at 500 °C with well-preserved inversion characteristics. This thermal reliability indicates that diamond CMOS inverters can be better monolithically integrated for applications in high-temperature environments in the future.

A regularized-interface method as a unified formulation for simulations of high-pressure multiphase flows

The injection of multi-species fluids into high-pressure and high-temperature environments beyond the species' critical points is commonly found in engineering applications. At these conditions, for immiscible species, both subcritical interfacial dynamics and supercritical mixing can coexist due to variations in temperature around the mixture critical point. The modeling of these complex transcritical phenomena for large-scale configurations is so far not possible. To address this issue, we propose the Regularized-Interface Method (RIM) as a unified formulation that can describe both sub- and supercritical processes as well as the transition between them. The proposed method is derived via filtering of the nanoscale interface-resolving formulation based on van der Waals' linear gradient theory. Thus, this approach allows for the consistent modeling of interfacial dynamics that vanishes at supercritical conditions, while significantly reducing the temporal and spatial resolution constraints of the original nanoscale formulation. The resulting RIM formulation is examined in interface-capturing simulations of sub-, trans-, and supercritical fuel injection processes, involving droplets and jets. These results highlight the importance of resolving spatio-temporal transitions from subcritical interfacial dynamics to supercritical mixing in high-pressure multiphase simulations, in contrast to commonly employed diffused-interface methods, where interfacial dynamics are often neglected.