Low-temperature Resistivity Research Articles

Effects of Environment-friendly Polymer Composite Modifiers on the Modulus and Pavement Performance of Asphalt Mixtures

Background: In the current context of low-carbon environment, it is particularly important to use waste plastics to prepare modifiers that increase the modulus of the bituminous mixture. Objectives: The study aimed to find out the influence of environment-friendly polymer composite modifier (E-FPCM) on modulus and pavement performance of bituminous mixture. Method: The influence of the optimum component E-FPCM on the dynamic modulus (DM) has been explored. The E-FPCM content’s effect on the rheological properties of bitumen has been analyzed. Also, the influence of E-FPCM on pavement performance has been analyzed. Results: The degree of influence on SR of bituminous mixture has been in the order of recycled low-density polyethene (R-LDPE) > aromatic oil > lignin fiber. The optimum composition of E-FPCM has been found to be 10% aromatic oil, 4.8% C9, 62% R-LDPE, 7.0% lignin fiber, 0.2% antioxidant 1076, 2% silane coupling agent, and 14% mineral powder. By using E-FPCM with the optimum components, the SBS bituminous mixture or 90# bituminous mixture has been found to meet the standard of a high-modulus bituminous mixture (HMBM). E-FPCM has been found to reduce the phase angle (δ) of bitumen and increase the complex shear modulus (G∗) and rutting factor [G∗/sin(δ)], which may help improve the rutting resistance (RR). Conclusion: E-FPCM is beneficial for improving the RR of the bituminous mixture, and reasonable content of E-FPCM has a great role in improving the water stability (WS) and low-temperature crack resistance (LTCR) of the bituminous mixture.

Sustainable application of recycled plastics in asphalt pavement: Case study of a trial in Newtonville, Ontario, Canada

Global research on using plastic waste in asphalt roads highlights its benefits: recycling waste, reducing greenhouse gas emissions, and providing an alternative to non-renewable asphalt binders. This study aims to bridge the gap between laboratory results and field performance of recycled plastic-modified asphalt in cold regions, promoting broader adoption. Laboratory analysis of core samples was performed as part of a quality assurance program. High-temperature rutting resistance was evaluated using the Hamburg wheel tracking test, while low-temperature cracking resistance was assessed through semi-circular bending testing. Results show that the impact of recycled plastics and fibers on rutting resistance varies with temperature, with the greatest benefit at the highest temperatures. For low-temperature cracking resistance, polyethylene terephthalate (PET) fibers outperform mixed plastics by delaying crack propagation. Low-temperature conditioning can induce thermal shrinkage in the asphalt mixture, slightly moderating the effects of recycled plastics and fibers.

Tensile strain-induced disorder and weak localization in SrRuO3 thin films on (100) KTaO3 substrates

Abstract SrRuO3 (SRO) thin (∼12 nm) films have been grown on KTaO3 (001) substrates by RF magnetron sputtering. The as-prepared films are under enormous in-plane tensile strain, which corresponds to the elastic energy of ∼1.5 MJ. Annealing in oxygen at 900 °C for 6 h relaxes strain, partially lowering the elastic energy. The surface topography shows a transition from granularity as the Ar+O2 pressure increases from 5 mTorr to 200 mTorr, with a simultaneous change in the average surface roughness from 4 nm to 0.8 nm. Annealing transforms the topography to island-type and enhances surface roughness. The films deposited at 5 mTorr are semiconducting, and annealing further enhances the resistivity. The ρ-T of films grown at 200 mTorr shows a metallic behavior with an inflection in the ρ-T at TC ∼ 150 K, FM transition. The low-temperature resistivity upturn shows the disordered nature of these films. The eq. ρ T = 1 σ 0 + a T 1 2 + a 1 T p 2 + b T α (p = 2 & α = 2) describes the transport behavior from 2 K to 300 K of 5 mTorr deposited films. In the 200 mTorr deposited film, the above eq. is valid at T < 95 K with p = 2 and α = 1.5. At TC < T ≤ 300 K, the ρ-T follows eq. ρ T = ρ 0 + ρ 1 T α with α = 1.3 and 1.5 for the as-grown and annealed films. The lower temperature ρ-T upturn appears to have contributions from the disorder-enhanced renormalized e-e interaction (REEI) and weak localization (WL) effects. The magnetoresistance behavior supports a substantial WL effect in the films grown at 200 mTorr. Our results establish a strong correlation between the nature of strain, surface topography, and carrier transport mechanisms.

A comprehensive study on the rheological properties of desulfurized rubberized asphalt and establishment of micro-scale mechanical models

Recently, understanding the complex relationship between the mechanical properties and material characteristics of desulfurized rubber asphalt has received significant research attention. In this study, the rheological properties of rubber asphalt prepared by three kinds of desulfurized rubber powder are analyzed, and the mechanical response of rubber asphalt mixture is predicted using various mathematical models. Firstly, the rheological properties of desulfurized rubber asphalt are assessed through multiple stress creep recovery test, linear amplitude scanning test, and low-temperature creep test. The results indicate that the high-temperature performance index of desulfurized rubber asphalt is highly sensitive to the degree of desulfurization. As the degree of desulfurization of the rubber powder increases, the fatigue damage rate of asphalt gradually decreases, leading to an increase in the fatigue life. Notably, the difference between the m-critical temperature and stiffness-critical temperature (ΔTc) for only ML40MA does not exceed the threshold value, indicating that it has the best low-temperature cracking resistance. Additionally, the swelling capacity of desulfurized rubber powder in asphalt is better than that of ordinary rubber powder. Finally, the comprehensive performance of desulfurized rubber asphalt is characterized based on the gray correlation method. The gray correlation coefficient of ML60MA is 0.78, which is higher than that of ML40MA and ML80MA, indicating its best overall performance.

Recyclable VOCs-free eutectic adhesive based on hydrogen bond fusion strategy with robust adhesion, flame retardancy, transparency, high durability, and low-temperature resistance

Although emerging supramolecular adhesives have addressed the challenge of traditional adhesives in terms of de-bonding through non-covalent interactions, they still face issues such as high synthetic difficulty, elevated costs, and inadequate adhesion strength, particularly under low temperatures. Additionally, achieving robust adhesion to low-energy hydrophobic surfaces remains a persistent challenge. This paper proposes a novel hydrogen bond fusion strategy to address these challenges, presenting the synthesis of a new HCX eutectogel, containing intramolecular fused hydrogen bonds and intermolecular hydrogen bonds. This approach enables the attainment of high-strength adhesion on both hydrophilic (up to 10.61 MPa) and hydrophobic (up to 4.87 MPa) substrates. Notably, the HCX eutectogel stands out for its ability to maintain stable adhesion performance at low temperatures (−80 °C & liquid nitrogen) and its extraordinary flame retardancy and recyclability. These findings contribute novel insights into the development of high-performance adhesives with multifunctionality, promising advancements in diverse applications.

Green and synergistic effects of buton rock asphalt and styrene-butadiene-styrene on asphalt performance: Focus on resistance to thermal oxygen aging

The enhancement of asphalt properties was investigated through utilizing the Buton rock asphalt (BRA) and styrene–butadiene–styrene (SBS) in this study. Despite of the splendid high-temperature resistance of the BRA-modified asphalt, it could be liable to low-temperature cracking. Hence, a composite BRA/SBS-modified asphalt was explored. The rheological tests, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) were employed for analyzing the rheological, thermal, and chemical stability properties of the samples. The findings demonstrated that SBS promoted the low-temperature crack resistance of the BRA-modified asphalt, and BRA improved the thermal stability and thermal oxygen aging resistance of the SBS-modified asphalt. Considering the overall anti-aging and anti-fatigue effectiveness, 2 % SBS and 10 % BRA were proposed as the appropriate dosages for the modified asphalt. The analysis of correlation revealed that the BRA could be introduced to mitigate the influence of aging on the performance of SBS-modified asphalt to resist the irreversible deformation. This study could address the limitations of the BRA-modified asphalt and promote its application in road constructions.

Performance Restoration of Aged SBS-Modified Asphalt in RAP via Dry-Process SBS modifier Diffusion at the Interface of Aggregate-Aged Asphalt-Virgin Asphalt

To address and recycle more RAP (Reclaimed Asphalt Pavement), dry-process SBS(Styrene-Butadiene-Styrene) modifier was applied in hot in-place recycling. Molecular simulation and laboratory experiments were conducted to investigate the diffusion behavior of dry-process SBS modifier on RAP surfaces and its effects on the properties of recycled asphalt and recycled asphalt mixtures (RAM). Molecular simulation results revealed that after the diffusion of dry-process SBS on RAP surfaces, the fractured and aged SBS molecules in the aged asphalt were replenished, leading to a 59.49% enhancement in the interface energy between aged asphalt and aggregates. Dry-process SBS exhibited bidirectional diffusion between RAP and virgin asphalt, with a preference for the intact SARA components of Virgin asphalt. The diffusion coefficient of the dry-process recycling system was significantly higher compared to conventional wet-process recycling, achieving a higher degree of fusion (DOB) between virgin and aged asphalt. Laboratory experiments demonstrated that dry-process recycling was more effective in restoring the performance of aged SBS-modified asphalt compared to wet-process recycling. At high RAP contents (80%, 100%), the asphalt mixtures from wet-process recycling failed to meet specifications for high-temperature permanent deformation resistance, low-temperature cracking resistance, and resistance to water damage. However, using 10% dry-process SBS modifier by mass of aged asphalt in RAP enabled 100% RAP content asphalt mixtures to meet specifications.

Towards the high RAP dosage obtained by refined processing influence on comprehensive performance of recycled asphalt mixture

The severe agglomeration of Reclaimed Asphalt Pavement (RAP) particles not only leads to high gradation variability during recycling, but also impedes the miscibility between new-old binders. This phenomenon imposes significant limitations on maximizing the utilization of RAP with high content and value. This paper first realized the effective separation of asphalt milling material by the self-developed RAP refined processing equipment to obtain coarse RAP with low binder content and fine RAP with high binder content. The fine RAP with high binder content underwent a deep rejuvenation process, and the recovery efficiency of the asphalt mortar was evaluated by CT scanning test, microscope observation test, and dynamic shear rheology test. Moreover, to investigate the strength formation characteristics of recycled asphalt mixtures with high RAP content, specific tests including wheel tracking test, three-point bending test, Hamburg Wheel Tracking test, dynamic modulus test, and two-point bending fatigue test, were conducted. By using the refined processing equipment, the asphalt film on the RAP can be precisely removed, thereby addressing the issue of aged binder agglomeration. In the coarse RAP with low binder content, the binder content was reduced to 1.48 %, allowing it to be used as a direct substitute for new aggregate, whereas the binder content of fine RAP exceeded 10 %. It was found that the direct incorporation of unrefined RAP enhanced the high-temperature stability and dynamic modulus of recycled asphalt mixture, but impacted their low-temperature cracking resistance, moisture stability, and fatigue performance. After refined processing and differentiated recycling design, the agglomeration of aged binder was reduced and the miscibility of new-old binders was improved, effectively enhancing the comprehensive performance of the recycled asphalt mixture. It should be noted that the mixing homogeneity and miscibility decrease as the RAP content exceeds 75 %, resulting in the reduction of moisture stability, cracking resistance, and fatigue performance of recycled asphalt mixture.

Research on cracking characteristics and failure modes of semi-flexible pavement materials

Semi-flexible pavement (SFP) is designed for heavy traffic but its susceptibility to cracking hinders its development and application. This study aims to investigate the cracking characteristics and failure modes of SFP materials through macroscopic tests and image processing, thereby guiding anti-cracking technology. First, the effects of gradation and bitumen content on cracking process curves were analyzed using three-point bending tests across a wide temperature range. Second, the variations in maximum tensile strain, tensile strength, and fracture energy were comparatively examined. Finally, the morphology of specimens at crack initiation and after complete fracture was analyzed using image processing techniques to quantify the failure modes. The results indicate that the SFP material exhibits elastic development and brittle damage at the low temperature, and viscoelastic development and ductile damage at medium and the high temperature. At the low temperature, the changes in maximum tensile strain and fracture energy are consistent. The primary weak points at crack initiation include internal cement failure, cement-bitumen interface failure, and bitumen-aggregate interface failure. After complete fracture, internal cement damage and bitumen-bitumen/aggregate interface damage are dominant. To improve low-temperature cracking resistance of SFP, it is recommended to increase the maximum aggregate size, add fine aggregates, and increase the bitumen content. Additionally, enhancing the internal cohesion and external bonding properties of bitumen can mitigate the negative effects of increased bitumen consumption. This study provides guidance on designing the SFP material to enhance its crack resistance.

Experimental study on the quasi-static tensile mechanical response of PTFE from 77 K to 293 K

PTFE’s exceptional low-temperature resistance makes it an ideal material for cryogenic aerospace fuel seals. However, the current understanding of its mechanical behaviors at low temperatures remains limited, posing potential design vulnerabilities. This study investigates the quasi-static mechanical properties of PTFE over a temperature range from 77 K to room temperature, with a particular focus on the effects of temperature and strain rate, which are key variables in sealing applications. The experimental conditions are categorized into ambient temperature (293 K), conventional low temperatures (233 K–293 K), and cryogenic temperatures (77 K–223 K). Testing was conducted at crosshead speeds of 1, 10, and 100 mm/min to evaluate their influence. The results reveal significant phase transition characteristics in PTFE’s low-temperature mechanical properties, with the effects of phase transitions far outweighing those of strain rate, leading to dramatic changes in the stress response, from elasticity through plasticity to fracture. Further analysis indicates that these effects are concentrated around the transition state temperature zone, with slower changes observed at other temperatures. This study highlights the critical importance of considering phase transitions in the low-temperature design of PTFE structures.

Influence of Foliar Application of Nanoparticles on Low Temperature Resistance of Rice Seedlings.

Chilling stress, a common abiotic factor, adversely affects the growth and biomass of rice seedlings during the early stages, ultimately reducing the yield. Effective strategies to mitigate these negative impacts are essential for improving rice productivity. The application of nanotechnology in agriculture, particularly nanoparticles (NPs), has shown a promising effect in alleviating chilling stress in plants. This study evaluates the effects of various nanoparticles, ZnO (0, 50, 100, and 200 mg/L), Fe2O3 (0, 50, 75, and 100 mg/L), TiO2 (0, 50, 75, and 100 mg/L), and CeO2 (0, 50, 75, and 100 mg/L) on the chilling resistance with one control (a water spray) under a normal temperature. Four rice cultivars: LLY-7108 and XZX-6 (Low-temperature-tolerant), and LLY-32 and ZJZ-17 (Low-temperature-susceptible) were tested in this experiment. Rice seedlings were subjected to low temperature conditions (12 h light 14 °C/12 h dark, at 10 °C) for five days, followed by seven days of recovery. The results of this study demonstrate that NPs significantly enhanced seedling height fresh/dry weight and root length compared to untreated controls under chilling stress. NP treatment also reduced the reactive oxygen species (ROS), malondialdehyde (MDA), and proline content, while enhancing superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, thereby mitigating oxidative damage. The four rice varieties exhibited clear signs of rapid growth recovery and positive physiological changes due to NPs' application. Among the tested cultivars, LLY-7108 showed the most substantial recovery and physiological responses, while ZJZ-17 exhibited the least. The findings of this study indicate that the foliar application of ZnO (100 mg/L), Fe2O3 (50 mg/L), TiO2 (50 mg/L), and CeO2 (75 mg/L) NPs effectively mitigates chilling stress in rice seedlings, likely by enhancing the antioxidant enzymatic activity while reducing the oxidative damage. This study highlights the potential of NPs as effective agents in reducing the adverse effects of chilling stress on rice.

The enhanced SO2 resistance of Fe-Ti catalyst by W/SO42− co-modification for NH3-SCR: A combined experimental and DFT study

It remains a great challenge to improve the low-temperature SO2 resistance of catalysts applied for selective catalytic reduction of NOx with NH3 (NH3-SCR). This work develops an outstanding SO2-tolerant Fe-Ti (FT) catalyst by W/SO42− co-modification via a sol–gel method using Fe(NO3)3·9H2O, tetrabutyl titanate, ammonium tungstate and thiourea as raw materials. The physicochemical characterizations, in-situ diffuse reflectance infrared Fourier transform (DRIFT) measurements and density functional theory (DFT) calculations were combined to reveal the underlying mechanisms. Although W doping can effectively enhance the surface acidity, NH3 adsorption on Lewis acid sites can still be restrained by competitive adsorption of SO2, whereas SO42− modification can enhance the adsorption stability of NH3 without being affected by SO2. Simultaneously, the NO adsorption ability on Fe sites can be significantly enhanced by W/SO42− co-modification. Furthermore, the W doping or SO42− modification can induce conversion of Fe3+ to Fe2+ to affect the redox property of Fe species. A proper amount of Fe2+ suppressed the oxidizability of FT catalyst to inhibit NH3 overoxidation to enhance N2 selectivity, and created more oxygen vacancies to generate larger amount of chemisorbed oxygen to facilitate NH3 dehydrogenation and NO oxidation. More importantly, the inhibition effect of SO2 adsorption on Fe sites was strengthened by W/SO42− co-modification. Consequently, the W/SO42− co-modified FT catalyst exhibited high activity with >90 % of NO conversion and >95 % of N2 selectivity within a broad window of 275–450 °C and possessed superior SO2 + H2O tolerance at 275 °C.

Ultra-Stretchable, Adhesive, Conductive, and Antifreezing Multinetwork Borate Ester-Based Hydrogel for Wearable Strain Sensor and VOC Absorption.

Hydrogels based on borate ester bonds exhibit remarkable tensile strength and self-healing ability, which make them a promising material for various biological research and strain sensor applications. However, in order to meet the practical application of hydrogel strain sensors, they must also show high conductivity, frost resistance, and proper adhesion, which is still a continuous challenge. Herein, a triple network hydrogel was prepared using poly(vinyl alcohol) (PVA) as the first network, ethylene imine polymer (PEI) as the second network, and poly(acrylamide-co-acrylic acid) copolymer (denoted as P(AM-Co-AA)) as the third network. 3-Carboxy-4-fluorophenylboronic acid (CFBS) was used as the cross-linking agent, glycerol (GL) was added to improve low-temperature resistance, and sodium chloride (NaCl) was incorporated to enhance electrical conductivity. The resulting PVA-CFBS@PEI@P(AM-Co-AA) triple network hydrogel exhibited impressive mechanical properties, including ultra tensile strength (4100%, 266.8 kPa), high toughness (6.5 MJ/m3), and low-temperature resistance (-60 °C). Additionally, it demonstrated high conductivity (σ = 1.83 mS/cm). The incorporation of CFBS endowed the hydrogel with excellent self-healing ability, while GL improved low-temperature resistance and strain sensing sensitivity (gauge factor (GF) = 2.8 (0-300%), GF = 5.6 (300-600%), GF = 8.7 (600-1000%)). The prepared hydrogel sensor can repetitively detect and differentiate between a wide range of human activities such as joint movements, frowning, and smiling. Additionally, the hydrogel demonstrated favorable mechanical properties at -20 °C (good adhesion, tensile strength: 1169.8%, 1.2 MPa; conductivity: 0.71 mS/cm, and strain sensing coefficient: GF = 1.3), making it suitable for applications in low-temperature environments. Furthermore, it also functions as an exceptional adsorbent, capable of selectively absorbing volatile organic compounds at high capacity (e.g., methanol: 1.80 g/g; acetone: 1.50 g/g).

Utilization of thermoplastic resin as foamed asphalt modifier in cold recycled mixtures

The utilization of foamed virgin asphalt in cold recycled mixtures results in insufficient bonding strength between aggregates, leading to rapid deterioration to the recycled asphalt pavement. This ultimately causes inefficient clean production and increased carbon emissions. The foaming performance of thermoplastic resin modified asphalt (TRA) under different foaming conditions was analyzed. Micro-scale chemical and physical tests were utilized to discover the foaming mechanism of TRA. The road performance of cold recycled mixtures with foamed TRA was evaluated through splitting, rutting and fatigue tests. The results showed that the increase in the TRA polar functional group index led to an increase in its surface tension, thus limiting its expansion capacity. However, the increase in the specific heat capacity of TRA indicated that it preserves a low viscosity level essential for its foaming efficacy post-ejection from the foaming machine, thereby enhancing its half-life. Furthermore, the dynamic viscosity of the TRA with an 8% thermoplastic resin dosage exceeded 40000 Pa s at 60 °C, meeting the specification requirements for high viscosity asphalt, while exhibiting a notably lower viscosity of only 120 mPa s at the foaming temperature of 170 °C. The observed low viscosity of the asphalt is anticipated to favorably enhance the formation of a stable foam structure. The mechanical properties and overall road performance of the cold recycled mixture with foamed TRA were significantly enhanced, especially in terms of moisture damage resistance and low-temperature crack resistance. The purpose of this paper is to serve as a valuable reference for investigating the mechanism of modified asphalt foaming and to enhance the efficiency of cold recycled pavement regeneration processes.

Waste coffee biochar and bi-oil composite modified rejuvenated asphalt: Preparation, characterization, and performance evaluation

In the realm of sustainable road construction, bio-oil has emerged as a promising and eco-friendly alternative for rejuvenating aged asphalt. Nevertheless, challenges arise due to poor stability, diminished performance at elevated temperatures, and limited anti-aging properties. This study introduces an innovative approach by blending biochar, obtained from the pyrolysis of waste coffee grounds, into bio-oil to create a composite modified regenerator. Initially, the study conducts a microscopic characterization of the biochar using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Subsequently, the rheological properties of this composite rejuvenated asphalt are evaluated across low, moderate, and high-temperature ranges using bending beam rheometer (BBR), linear amplitude sweep (LAS), and multiple stress creep and recovery (MSCR) tests. Departing from the traditional emphasis on initial property restoration, it further delves into performance alterations after re-aging of rejuvenated asphalt through temperature sweep (TS) and Fourier transform infrared spectroscopy (FTIR) tests, providing a comprehensive assessment of the anti-aging characteristics of rejuvenated asphalt. Additionally, gel permeation chromatography (GPC) is employed to quantitatively analyze the changes in asphalt molecular weight distribution. The microscopic characterization reveals the development of a rough and porous structure within the biochar, facilitating enhanced adhesion and interaction between the rejuvenator and the asphalt binder. Moreover, bio-oil rejuvenated asphalt exhibits excellent low-temperature crack resistance and moderate-temperature fatigue resistance. Following the incorporation of biochar, notable enhancements in high-temperature rutting resistance and anti-aging properties are observed, validating the efficacy of the biochar with bio-oil composite modified regenerator. To achieve optimal performance outcomes, a biochar content of 6 % (as a proportion of aged asphalt), corresponding to a 1:1 ratio of biochar to bio-oil, is recommended. Under this condition, the properties of the composite modified rejuvenated asphalt demonstrate comparability to those of the original asphalt. In summary, this research underscores the potential for integrating waste coffee biochar material into infrastructure development, thereby promoting circular economy principles and advancing more sustainable construction practices.

Significant Effects of Adding Mode on Low-Temperature De-NOx Performance and SO2 Resistance of a MnCeTiOx Catalyst Prepared by the Co-Precipitation Method

Significant Effects of Adding Mode on Low-Temperature De-NOx Performance and SO2 Resistance of a MnCeTiOx Catalyst Prepared by the Co-Precipitation Method

One-pot preparation of strong, tough, frost-resistant and recyclable organohydrogels via Hofmeister effect and its application for electronic devices

Conductive hydrogels have shown a great potential in the field of flexible electronics. However, it is difficult to combine high strength and high toughness in conductive hydrogels prepared by conventional methods, which limits their applications in various fields. In this work, we pioneered a facile and cost-effective strategy to prepare soy protein isolate/poly(vinyl alcohol) (SPI/PVA) conductive hydrogels with high strength, toughness, low-temperature resistance, and recyclability by introducing all the salts into the prescuor solution directly. To solve the problem of unable to directly introducing high concentration Na3Cit into the soy protein isolate/PVA solution, MgCl2 was used to alleviate the strong salting-out effect of Na3Cit. Thus the stable SPI/PVA/EG/MgCl2/Na3Cit complex solution was obtained and the SPI/PVA/EG/MgCl2/Na3Cit (SPEMS) organohydrogel was prepared by the freezing/thawing process. The optimum tensile strength of the SPEMS organohydrogel was 1.1±0.07 MPa, and the elongation at break was 701.3±23.67 %, respectively. Meanwhile, the ionic conductivity of the organohydrogel was as high as 1.7±0.01 S/m. Finally, the EG/H2O binary solvent system endowed the organohydrogel with excellent low-temperature resistance (freezing point of −19.4 °C). The strain sensors assembled with SPEMS organohydrogels were characterized by high sensitivity (GF = 3.2, strain range from 20 %-500 %) and long-term stability. The flexible all-solid-state supercapacitor assembled with SPEMS organohydrogel as the electrolyte and activated carbon as the electrodes has a high area specific capacitance (113.76 mF/cm2) and good cycling stability (capacitance retention of 81.62 % after 1,000 charging and discharging cycles) at room temperature.

CsGAT1 modulates GABA metabolism and positively regulates cold resistance in tea plants

Tea plants (Camellia sinensis) are perennial woody economic crops that are often exposed to a range of abiotic stresses, especially low temperatures, during development. γ-Aminobutyric acid (GABA) is a nonprotein amino acid widely distributed in plants that is involved in the low-temperature response of plants. Here, we found that CsGAT1 was upregulated in tea leaves subjected to low-temperature stress according to transcriptomic data. Heterologous expression of CsGAT1 in a yeast mutant revealed that it specifically transports GABA. Subcellular localization assays revealed that CsGAT1 was located on the plasma membrane. The organizational localization experiments revealed that the expression level of CsGAT1 was relatively high in the old leaves and roots and relatively low in the flowers. Testing of different cold-tolerant tea germplasm resources revealed that cultivars with relatively low cold resistance presented relatively low CsGAT1 expression and GABA levels. In addition, Arabidopsis plants overexpressing CsGAT1 presented high levels of GABA accumulation and significant low-temperature resistance. In summary, we believe that CsGAT1 regulates the ability of tea plants to resist low-temperature stress by changing the concentration of GABA inside and outside the cell. This study provides a theoretical basis for breeding new tea cultivars with strong resistance to low-temperature stress during production.

Genome-wide analysis of fatty acid desaturase (FAD) gene family in Camellia sinensis: Identification, expression and their biochemical functions in low temperature resistance

Fatty acid desaturase (FAD) is critical for unsaturated fatty acids (UFAs) biosynthesis and plays crucial roles in plants' response to low temperature. Nevertheless, a comprehensive genomic analysis of the FAD gene family in Camellia sinensis remain unreported. This study employed bioinformatics to identify 17 CsFAD genes, which are unequally distributed across 9 chromosomes. CsFAD proteins are localized to chloroplasts and/or endoplasmic reticulum (ER) by subcellular localization predictions. Phylogenetic categorization divides CsFADs into six subfamilies. The cis-elements are related to hormonal regulation and adversity response. Additionally, differential expression patterns of CsFADs across various tissues were observed. qRT-PCR analysis revealed a marked upregulation in the expression of CsSLD3 and CsSLD4 (encoding sphingolipid Δ8 desaturase) under cold stress conditions. Moreover, subcellular localization assays in tobacco leaves confirmed the presence of CsSLD3 and CsSLD4 within ER. Yeast heterologous expression demonstrated the capacity of CsSLD3/4 to transform ceramide(t18:0) into ceramide(t18:1), and overexpression of CsSLD3/4 enhanced yeast tolerance to low temperature. Thus, this comprehensive analysis of the CsFAD gene family furnishes a robust foundation for future study into the biological functions of CsFAD genes, and offers a profound insight into their regulatory roles in stress resilience.

Experimental Study on Pavement Performance of Warm High Modulus Mixture WHMM-13

In order to solve the dusting and rutting problems of hot mix asphalt mixture during construction and operation, rutting test, bending test, Marshall stability test, freeze-thaw splitting test, uniaxial compression dynamic modulus test, overlay test, and four-point bending fatigue life test are applied on WHMM-13 to study the high-temperature stability, low-temperature cracking resistance, water stability, anti-reflection crack performance and fatigue durability in comparison with HMM-13. The results show that, compared to HMM-13, the dynamic stability and dynamic modulus (45 ℃, 10 Hz) of WHMM- 13 are improved by 10.0% and 47% respectively, and the rutting depth is reduced by 27.3%, indicating that the high temperature stability of WHMM-13 has been greatly improved. As for low temperature cracking resistance, the bending failure strain, stiffness modulus, flexural tensile strength and rupture energy of WHMM-13 are slightly lower than those of HMM-13. As for water stability, the residual stability of WHMM-13 in immersion Marshall test is 87.5%, and the splitting strength is 82.3%, both higher than that of HMM-13. As for anti-reflection crack performance, the total tensile rupture energy of WHMM-13 is 2.32 times that of HMM-13, with cracking resistance index (CRI) increased by 25%, which shows that WHMM-13 has better strength, can effectively prevent the crack from spreading and effectively improve the cracking resistance capacity of asphalt pavement. As for fatigue durability, the fatigue life of WHMM-13 is 5.4% lower than that of HMM-13, with bending stiffness modulus and cumulative dissipation energy reduced by 11.3% and 2.8% respectively, indicating that the fatigue durability of WHMM-13 is slightly reduced.