Superhydrophobic surface is a promising strategy for antibacterial and corrosion protection.However,the use of harmful fluorine-containing materials,poor mechano-chemical stability,the addition of fungicides and poor ...Superhydrophobic surface is a promising strategy for antibacterial and corrosion protection.However,the use of harmful fluorine-containing materials,poor mechano-chemical stability,the addition of fungicides and poor corrosion resistance often limit its practical application.In this paper,a high-robustness pho-tothermal self-healing superhydrophobic coating is prepared by simply spraying a mixture of hydropho-bically modified epoxy resin and two kinds of modified nanofillers(carbon nanotubes and SiO2)for long-term anticorrosion and antibacterial applications.Multi-scale network and lubrication structures formed by cross-linking of modified carbon nanotubes and repeatable roughness endow coating with high ro-bustness,so that the coating maintains superhydrophobicity even after 100 Taber abrasion cycles,20 m sandpaper abrasion and 100 tape peeling cycles.The synergistic effect of antibacterial adhesion and pho-tothermal bactericidal activity endows coating with excellent antibacterial efficiency,which against Es-cherichia coli(E.coli)and Staphylococcus aureus(S.aureus)separately reaches 99.6% and 99.8%.Moreover,the influence of modified epoxy resin,superhydrophobicity,organic coating and coating thicknesses on the anticorrosion of magnesium(Mg)alloy is systematically studied and analyzed.More importantly,the prepared coating still exhibits excellent self-cleaning,anticorrosion and antibacterial abilities after 20 m abrasion.Furthermore,the coating exhibits excellent adhesion(level 4B),chemical stability,UV radiation resistance,high-low temperature alternation resistance,stable heat production capacity and photother-mal self-healing ability.All these excellent performances can promote its application in a wider range of fields.展开更多
Hydraulic fracturing is a key technology for the efficient development of deep oil and gas reservoirs.However,fracture propagation behavior is influenced by rock elastoplasticity and thermal stress,making it difficult...Hydraulic fracturing is a key technology for the efficient development of deep oil and gas reservoirs.However,fracture propagation behavior is influenced by rock elastoplasticity and thermal stress,making it difficult for traditional linear elastic models to accurately describe its dynamic response.To address this,this study employs the Continuum-Discontinuum Element Method(CDEM),incorporating an elastoplastic constitutive model,thermo-hydro-mechanical(THM)coupling effects,and cohesive zone characteristics at the fracture tip to establish a numerical model for hydraulic fracture propagation in deep elastoplastic reservoirs.A systematic investigation was conducted into the effects of fluid viscosity,reservoir temperature,injection rate,elastic modulus,and horizontal stress difference on fracture propagation.The findings show that a larger horizontal stress differential results in a more rectangular fracture geometry,a shorter fracture length,and a wider fracture.An increase in elastic modulus has a negligible impact on fracture length but reduces fracture width,resulting in a rounded rectangular morphology.Elevated reservoir temperature induces thermal tensile stress around the fracture,mitigating in-situ stress effects and reducing both breakdown and propagation pressures.Higher injection rates and fluid viscosity increase fracture initiation difficulty,promoting shorter but wider fractures with enhanced height growth beyond interlayer barriers.Additionally,horizontal stress significantly affects near-fracture plastic deformation:when the stress difference increases from 10 to 25 MPa,the maximum cumulative plastic strain in the surrounding rock rises by 66.67%.By integrating elastoplasticity and thermal stress effects,this study overcomes the limitations of conventional hydraulic fracturing simulations,offering novel insights for optimizing extraction strategies in deep unconventional reservoirs.展开更多
Superhydrophobic surfaces with water-repelling ability have important applications, such as self-cleaning, antibacterial and corrosion protection. However, the using of harmful fluorinated materials and its poor mecha...Superhydrophobic surfaces with water-repelling ability have important applications, such as self-cleaning, antibacterial and corrosion protection. However, the using of harmful fluorinated materials and its poor mechanochemical stability limit its practical application. Herein, a fluorine-free, robust and self-healing superhydrophobic surface is prepared through a two-step method of laser processing and spraying coating for anticorrosion and antibacterial applications. Laser processing is used to construct periodic micron-sized pillars for obtaining strong interface bonding between coating and substrate by mechanical interlocking effect, and as an ‘armor’, preventing the removal of the coating. The coating consists of epoxy resin (EP), hexadecyltrimethoxysilane (HDTMS) and γ-aminopropyltriethoxysilane treated Cu2O (KH550-Cu2O). The superhydrophobic surface can withstand various mechanical durability tests, such as multiple sandpaper abrasion and tape peeling cycles. It exhibits excellent corrosion inhibition efficiency (ηp > 99 %) on Mg alloy, Tinplate and Al alloy, which results from superhydrophobicity and organic coating. The superhydrophobicity endows surface with excellent antibacterial adhesion performance in a static liquid environment. The bactericidal activity of KH550-Cu2O can effectively inactivate the bacteria in contact with the surface and the free bacteria, providing excellent antibacterial ability in a dynamic liquid environment. It still exhibits good anticorrosion and antibacterial abilities after multiple mechanical abrasion cycles due to the outstanding mechanical durability. Moreover, it exhibits outstanding self-healing ability to plasma etching and oil contamination, self-cleaning ability under air and oil conditions, and chemical stability against acids and alkalis solution. All the above excellent performances promote its application in a wider range of fields.展开更多
In order to satisfy the needs of different applications and more complex intelligent devices,smart control of surface wettability will be necessary and desirable,which gradually become a hot spot and focus in the fiel...In order to satisfy the needs of different applications and more complex intelligent devices,smart control of surface wettability will be necessary and desirable,which gradually become a hot spot and focus in the field of interface wetting.Herein,we review interfacial wetting states related to switchable wettability on superwettable materials,including several classical wetting models and liquid adhesive behaviors based on the surface of natural creatures with special wettability.This review mainly focuses on the recent developments of the smart surfaces with switchable wettability and the corresponding regulatory mechanisms under external stimuli,which is mainly governed by the transformation of surface chemical composition and geometrical structures.Among that,various external stimuli such as physical stimulation(temperature,light,electric,magnetic,mechanical stress),chemical stimulation(pH,ion,solvent)and dual or multi-triggered stimulation have been sought out to realize the regulation of surface wettability.Moreover,we also summarize the applications of smart surfaces in different fields,such as oil/water separation,programmable transportation,anti-biofouling,detection and delivery,smart soft robotic etc.Furthermore,current limitations and future perspective in the development of smart wetting surfaces are also given.This review aims to offer deep insights into the recent developments and responsive mechanisms in smart biomimetic surfaces with switchable wettability under external various stimuli,so as to provide a guidance for the design of smart surfaces and expand the scope of both fundamental research and practical applications.展开更多
In order to further optimize the cultivation and agronomic technology of Guilin Maojian tea gardens, the effects, efficiencies and costs of different farming methods and their effects on the physiochemical properties ...In order to further optimize the cultivation and agronomic technology of Guilin Maojian tea gardens, the effects, efficiencies and costs of different farming methods and their effects on the physiochemical properties of tea garden soil were studied through the modification of the test sites with the non-farming land as the control. The results showed that human farming, mini-tiller farming and crawler tractor farming could improve the physical and chemical properties of soil. After farming, the soil had good water retention but low moisture content compared to the control group, while the soil bulk density and hardness value were significantly lower than those of the control, and the porosity of soil was significantly higher than that of contrast. With the passage of time, soil bulk density and hardness value gradually increased after farming, while the porosity of soil decreased gradually. There were great differences in the effects, efficiencies and costs of different farming methods. Crawler tractor had the best and most stable farming effect, and the operation efficiency was 10 times that of human farming while the cost was only 0.39 times of human farming. Therefore, it was feasible to adopt mini-tiller or crawler tractor to carry out mechanical farming of Guilin Maojian tea garden, which provided theoretical references for the soil property improvement using mechanical farming and was favorable for promoting the popularization of farming machines and the acceleration of mechanization of tea gardens. But for tea plantations that are intended to be mechanized, apart from the mechanical and technical personnel to be configured in place, the site conditions, planting modes and mechanical way reservation of tea garden should be planned accordingly. It is recommended to select flat or gentle slope for reclamation, and preference is given to non-sexual tea tree varieties with big line spacing over 180 cm long. Moreover, the main road construction should be more than 3.0 m, and trunk road 2.0 m or above. And isolation ditch and drain should be set between the tea garden and the surrounding mountain forests and farmland.展开更多
The surface structures of heterogeneous catalysts significantly impact catalytic performance,especially for structure-sensitive reactions.In this study,we employed surface techniques such as low-energy ion scattering ...The surface structures of heterogeneous catalysts significantly impact catalytic performance,especially for structure-sensitive reactions.In this study,we employed surface techniques such as low-energy ion scattering spectroscopy,X-ray photoelectron spectroscopy,and Fourier transform infrared spectroscopy with CO as a probe(CO-FTIR)to investigate the surface dynamics of Rh/Al_(2)O_(3)catalysts for propane dehydrogenation(PDH).We observed a notable induction process for PDH on Rh/Al_(2)O_(3)catalysts,marked by significant variations in propane conversion,methane,and propylene selectivities.These changes were attributed to substantial coke formation.Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy)and CO-FTIR revealed the coexistence of Rh nanoparticles,clusters,and single atoms on the surface.Through various dynamic quasi in-situ characterizations,we found that coke preferentially covered Rh clusters,thereby inhibiting C-C bond breaking and methane formation.Meanwhile,Rh single atoms were less affected by coke coverage and remained exposed as active and selective sites for PDH,favoring propylene production.This work underscores the sensitivity of PDH to the sizes of Rh species,with isolated Rh single atoms promoting propylene formation.展开更多
Adversarial distillation(AD)has emerged as a potential solution to tackle the challenging optimization problem of loss with hard labels in adversarial training.However,fixed sample-agnostic and student-egocentric atta...Adversarial distillation(AD)has emerged as a potential solution to tackle the challenging optimization problem of loss with hard labels in adversarial training.However,fixed sample-agnostic and student-egocentric attack strategies are unsuitable for distillation.Additionally,the reliability of guidance from static teachers diminishes as target models become more robust.This paper proposes an AD method called Learnable Distillation Attack Strategies and Evolvable Teachers Adversarial Distillation(LDAS&ET-AD).Firstly,a learnable distillation attack strategies generating mechanism is developed to automatically generate sample-dependent attack strategies tailored for distillation.A strategy model is introduced to produce attack strategies that enable adversarial examples(AEs)to be created in areas where the target model significantly diverges from the teachers by competing with the target model in minimizing or maximizing the AD loss.Secondly,a teacher evolution strategy is introduced to enhance the reliability and effectiveness of knowledge in improving the generalization performance of the target model.By calculating the experimentally updated target model’s validation performance on both clean samples and AEs,the impact of distillation from each training sample and AE on the target model’s generalization and robustness abilities is assessed to serve as feedback to fine-tune standard and robust teachers accordingly.Experiments evaluate the performance of LDAS&ET-AD against different adversarial attacks on the CIFAR-10 and CIFAR-100 datasets.The experimental results demonstrate that the proposed method achieves a robust precision of 45.39%and 42.63%against AutoAttack(AA)on the CIFAR-10 dataset for ResNet-18 and MobileNet-V2,respectively,marking an improvement of 2.31%and 3.49%over the baseline method.In comparison to state-of-the-art adversarial defense techniques,our method surpasses Introspective Adversarial Distillation,the top-performing method in terms of robustness under AA attack for the CIFAR-10 dataset,with enhancements of 1.40%and 1.43%for ResNet-18 and MobileNet-V2,respectively.These findings demonstrate the effectiveness of our proposed method in enhancing the robustness of deep learning networks(DNNs)against prevalent adversarial attacks when compared to other competing methods.In conclusion,LDAS&ET-AD provides reliable and informative soft labels to one of the most promising defense methods,AT,alleviating the limitations of untrusted teachers and unsuitable AEs in existing AD techniques.We hope this paper promotes the development of DNNs in real-world trust-sensitive fields and helps ensure a more secure and dependable future for artificial intelligence systems.展开更多
Water pollution remains one of the most pressing global challenges,driving an urgent need for advanced sustainable treatment materials.Derived from cellulose,the most abundant natural polymer on earth,cellulose aeroge...Water pollution remains one of the most pressing global challenges,driving an urgent need for advanced sustainable treatment materials.Derived from cellulose,the most abundant natural polymer on earth,cellulose aerogels(CAs)have become a highly promising candidate due to their unique three-dimensional porous structure,low density,high specific surface area,biodegradability and easy functionalization.Inspiration from the material and structural designs of natural biological systems has also effectively promoted the development and multifunctional applications of high-performance aerogels,positioning cellulose aerogels as a key area of research in the field of water treatment.This review systematically summarizes recent advancements in the design and functionalization strategies of cellulose aerogels specifically tailored for water pollution treatment.Firstly,it provides a comprehensive overview of CAs classification(native,regenerated,derivative,and composite),principal preparation methodologies including sol-gel processes and drying techniques(supercritical,freeze,and ambient pressure drying),and crucial functionalization approaches(such as surface chemical modification,incorporation of functional materials,and biomimetic structural design.).Subsequently,the review elaborates on the diverse applications of functionalized CAs in tackling various water contaminants,including efficient oil-water separation,removal of heavy metal ions,adsorption of organic dyes,treatment of emerging pollutants like microplastics,and solar-driven water desalination.The underlying pollutant removal mechanisms are analyzed in depth,encompassing physical adsorption,size sieving,interfacial wettability control,electrostatic interactions,coordination/ion exchange,photothermal conversion,catalytic degradation,and synergistic effects.This review provides insights for developing advanced cellulose-based aerogels,while highlighting current challenges and future perspectives in water treatment.展开更多
The periosteum,a fibrous tissue membrane covering bone surfaces,is critical to osteogenesis and angiogenesis in bone reconstruction.Artificial periostea have been widely developed for bone defect repair,but most of th...The periosteum,a fibrous tissue membrane covering bone surfaces,is critical to osteogenesis and angiogenesis in bone reconstruction.Artificial periostea have been widely developed for bone defect repair,but most of these are lacking of periosteal bioactivity.Herein,a biomimetic periosteum(termed PEC-Apt-NP-Exo)is prepared based on an electrospun membrane combined with engineered exosomes(Exos).The electrospun membrane is fabricated using poly(ε-caprolactone)(core)-periosteal decellularized extracellular matrix(shell)fibers via coaxial elec-trospinning,to mimic the fibrous structure,mechanical property,and tissue microenvironment of natural periosteum.The engineered Exos derived from M2 macrophages are functionalized by surface modification of bone marrow mesenchymal stem cell(BMSC)-specific aptamers to further enhance cell recruitment,immuno-regulation,and angiogenesis in bone healing.The engineered Exos are covalently bonded to the electrospun membrane,to achieve rich loading and long-term effects of Exos.In vitro experiments demonstrate that the biomimetic periosteum promotes BMSC migration and osteogenic differentiation via Rap1/PI3K/AKT signaling pathway,and enhances vascular endothelial growth factor secretion from BMSCs to facilitate angiogenesis.In vivo studies reveal that the biomimetic periosteum promotes new bone formation in large bone defect repair by inducing M2 macrophage polarization,endogenous BMSC recruitment,osteogenic differentiation,and vascu-larization.This research provides valuable insights into the development of a multifunctional biomimetic peri-osteum for bone regeneration.展开更多
Calcium carbide,a bulky and cheap raw chemical,is traditionally depolymerized by water to release acetylene,allowing the downstream organic transformation.In this study,hydrogen sulfide(H_(2)S),an industrial waste gas...Calcium carbide,a bulky and cheap raw chemical,is traditionally depolymerized by water to release acetylene,allowing the downstream organic transformation.In this study,hydrogen sulfide(H_(2)S),an industrial waste gas,has been exploited to depolymerize calcium carbide,which represents a strategy for the comprehensive utilization of both hydrogen sulfide and calcium carbide.As a proof of concept,a three-component condensation reaction was established to prepare thioamides directly from hydrogen sulfide and calcium carbide in high yields.Leveraging the unique properties of thioamides that possess both nucleophilic sulfur and electrophilic carbon sites,a series of novel tandem reactions were further developed to construct structurally diverse heterocyclic compounds.Our strategy not only provides a new chemical pathway for calcium carbide depolymerization,but also offers a solution for the utilization of hazardous hydrogen sulfide gas.More importantly,this approach facilitates the comprehensive and sustainable utilization of the calcium carbide resource.展开更多
Recent years have witnessed significant progress in quantum communication and quantum internet with the emerging quantum photonic chips,whose characteristics of scalability,stability,and low cost,flourish and open up ...Recent years have witnessed significant progress in quantum communication and quantum internet with the emerging quantum photonic chips,whose characteristics of scalability,stability,and low cost,flourish and open up new possibilities in miniaturized footprints.Here,we provide an overview of the advances in quantum photonic chips for quantum communication,beginning with a summary of the prevalent photonic integrated fabrication platforms and key components for integrated quantum communication systems.We then discuss a range of quantum communication applications,such as quantum key distribution and quantum teleportation.Finally,the review culminates with a perspective on challenges towards high-performance chip-based quantum communication,as well as a glimpse into future opportunities for integrated quantum networks.展开更多
Multimode waveguide bend is one of the key components for realizing high-density mode-division multiplexing systems on chip.However,the reported multimode waveguide bends are either large,bandwidth-limited or fabricat...Multimode waveguide bend is one of the key components for realizing high-density mode-division multiplexing systems on chip.However,the reported multimode waveguide bends are either large,bandwidth-limited or fabrication-complicated,which hinders their applications in future high-density multimode photonic circuits.Here we propose a compact multimode waveguide bend supporting four TE modes simply by shape-optimizing with transformation optics.The shape of the waveguide is optimized in the virtual space with gradient distribution of the refractive index,so that the scattering loss and intermode cross talk are well suppressed.After conformal mapping back into the physical space,a compact(effective radius of 17μm)multimode bending waveguide is obtained.Simulations show that the proposed multimode waveguide bend has little loss(<0.1 dB)and low cross talk(<−20 dB)throughout an ultrabroad wavelength range of 1.16–1.66μm.We also fabricated the shape-optimized multimode bending waveguide on a silicon-on-insulator wafer.At 1550 nm wavelength,the measured excess losses for the four lowest-order TE modes are less than 0.6 dB,and the intermode cross talks are all below−17 dB.Our study paves the way for realizing high-density and large-scale multimode integrated optical circuits for optical interconnect.展开更多
Gold nanoparticles （Au NPs） have been widely utilized in biomedical appli- cations owing to their attractive features and biocompatibility, which greatly increase the risk of humans＂ being exposed to Au NPs, includ...Gold nanoparticles （Au NPs） have been widely utilized in biomedical appli- cations owing to their attractive features and biocompatibility, which greatly increase the risk of humans＂ being exposed to Au NPs, including pregnant women. In contrast to mature cells, embryos are more susceptible to outside disruptive stimuli. Nonetheless, a possible inhibitory effect of nanomaterials on embryonic development is usually ignored as long as the NPs do not have significant cytotoxic effects. According to our results, a minimal ＂nontoxic＂ concentration of Au NPs during early pregnancy can have lethal inhibitory effects on embryos in vivo and in vitro. We conducted important experiments on the influence of Au NPs on embryonic development and found that Au NPs can disturb embryonic development in a size- and concentration-dependent manner. Au NPs of 15 nm in diameter downregulated the expression pattern of distinct germ layer markers both at mRNA and protein levels; this action prevented differentiation of all three embryonic germ layers. Consequentl~ fetal resorption was observed. Our work reveals the impact of Au NPs on embryonic development and will provide an important guidance and serve as a reference for biomedical applications of Au NPs with minimal side effects.展开更多
A bounce universe model with a scale-invariant and stable spectrum of primordial density perturbations was constructed using a consistent truncation of the D-brane dynamics from Type IIB string theory. A coupling was ...A bounce universe model with a scale-invariant and stable spectrum of primordial density perturbations was constructed using a consistent truncation of the D-brane dynamics from Type IIB string theory. A coupling was introduced between the tachyon field and the adjoint Higgs field on the D3-branes to lock the tachyon at the top of its potential hill and to model the bounce process,which is known as the Coupled Scalar and Tachyon Bounce(CSTB) Universe. The CSTB model has been shown to be ghost free,and it fulfils the null energy condition; in addition, it can also solve the Big Bang cosmic singularity problem. In this paper we conduct an extensive follow-up study of the parameter space of the CSTB model. In particular we are interested in the parameter values that can produce a single bounce to arrive at a radiation-dominated universe. We further establish that the CSTB universe is a viable alternative to inflation, as it can naturally produce a sufficient number of e-foldings in the locked inflation epoch and in the post-bounce expansion to overcome the four fundamental limitations of the Big Bang cosmology, which are flatness, horizon,homogeneity and singularity, resulting in a universe of the current size.展开更多
A fluorine-free and multifunctional superhydrophobic coating(r-MSC)was prepared by the one-step spraying method.The coating had superhydrophobic and low-adhesion properties with the water contact angle of 161.5°�...A fluorine-free and multifunctional superhydrophobic coating(r-MSC)was prepared by the one-step spraying method.The coating had superhydrophobic and low-adhesion properties with the water contact angle of 161.5°�1°and the sliding angle of 3.2°�0.5°.It could be prepared by spraying while maintaining superhydrophobic surface characteristics on any substrates.The coating owed outstanding mechanical durability and chemical stability.Moreover,the coating also possessed the ability of self-cleaning,anti-fouling,anti-icing,and flame retardant ability.Importantly,the presence of multifunc-tional coating endowed the substrate with both water-resistant and fireproof properties.Besides,it also showed excellent oil-water separation ability,which presented the oil-water separation efficiency of over 90%for different types of oils after 10 separation cycles.Furthermore,the coating could improve corrosion inhibition performance and the corrosion current density was reduced by two orders of magnitude from the polarization curve.The r-MSC had the advantages of simple preparation,fluorine-free,environ-mentally friendly and appropriate for large-area fabrication,which could be applied to various fields.展开更多
基金the National Natural Science Foundation of China(Nos.U2106226,52105297)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.52021003)the Science and Technology Development Project of Jilin Province(Nos.20210203022SF,20210508029RQ).
文摘Superhydrophobic surface is a promising strategy for antibacterial and corrosion protection.However,the use of harmful fluorine-containing materials,poor mechano-chemical stability,the addition of fungicides and poor corrosion resistance often limit its practical application.In this paper,a high-robustness pho-tothermal self-healing superhydrophobic coating is prepared by simply spraying a mixture of hydropho-bically modified epoxy resin and two kinds of modified nanofillers(carbon nanotubes and SiO2)for long-term anticorrosion and antibacterial applications.Multi-scale network and lubrication structures formed by cross-linking of modified carbon nanotubes and repeatable roughness endow coating with high ro-bustness,so that the coating maintains superhydrophobicity even after 100 Taber abrasion cycles,20 m sandpaper abrasion and 100 tape peeling cycles.The synergistic effect of antibacterial adhesion and pho-tothermal bactericidal activity endows coating with excellent antibacterial efficiency,which against Es-cherichia coli(E.coli)and Staphylococcus aureus(S.aureus)separately reaches 99.6% and 99.8%.Moreover,the influence of modified epoxy resin,superhydrophobicity,organic coating and coating thicknesses on the anticorrosion of magnesium(Mg)alloy is systematically studied and analyzed.More importantly,the prepared coating still exhibits excellent self-cleaning,anticorrosion and antibacterial abilities after 20 m abrasion.Furthermore,the coating exhibits excellent adhesion(level 4B),chemical stability,UV radiation resistance,high-low temperature alternation resistance,stable heat production capacity and photother-mal self-healing ability.All these excellent performances can promote its application in a wider range of fields.
基金supported by the Shandong Provincial Natural Science Foundation for Distinguished Young Scholars(Grant No.ZR2024JQ012)This research was financially supported by the National Natural Science Foundation of China(General Program,Grant No.52474069)This research was financially supported by the Natural Gas Research Institute of Shaanxi Yanchang Petroleum(Group)Co.,Ltd.(Grant No.TYTY0824SFW0003).
文摘Hydraulic fracturing is a key technology for the efficient development of deep oil and gas reservoirs.However,fracture propagation behavior is influenced by rock elastoplasticity and thermal stress,making it difficult for traditional linear elastic models to accurately describe its dynamic response.To address this,this study employs the Continuum-Discontinuum Element Method(CDEM),incorporating an elastoplastic constitutive model,thermo-hydro-mechanical(THM)coupling effects,and cohesive zone characteristics at the fracture tip to establish a numerical model for hydraulic fracture propagation in deep elastoplastic reservoirs.A systematic investigation was conducted into the effects of fluid viscosity,reservoir temperature,injection rate,elastic modulus,and horizontal stress difference on fracture propagation.The findings show that a larger horizontal stress differential results in a more rectangular fracture geometry,a shorter fracture length,and a wider fracture.An increase in elastic modulus has a negligible impact on fracture length but reduces fracture width,resulting in a rounded rectangular morphology.Elevated reservoir temperature induces thermal tensile stress around the fracture,mitigating in-situ stress effects and reducing both breakdown and propagation pressures.Higher injection rates and fluid viscosity increase fracture initiation difficulty,promoting shorter but wider fractures with enhanced height growth beyond interlayer barriers.Additionally,horizontal stress significantly affects near-fracture plastic deformation:when the stress difference increases from 10 to 25 MPa,the maximum cumulative plastic strain in the surrounding rock rises by 66.67%.By integrating elastoplasticity and thermal stress effects,this study overcomes the limitations of conventional hydraulic fracturing simulations,offering novel insights for optimizing extraction strategies in deep unconventional reservoirs.
基金financially supported by the National Natural Science Foundation of China(Nos.U2106226,U22A0183,52105297)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.52021003)+2 种基金the Science and Technology Development Project of Jilin Province(Nos.20210203022SF,20210508029RQ)the JLU Science and Technology Innovative Research Team(No.2020TD-03)the Project funded by China Postdoctoral Science Foundation(No.2022TQ0117).
文摘Superhydrophobic surfaces with water-repelling ability have important applications, such as self-cleaning, antibacterial and corrosion protection. However, the using of harmful fluorinated materials and its poor mechanochemical stability limit its practical application. Herein, a fluorine-free, robust and self-healing superhydrophobic surface is prepared through a two-step method of laser processing and spraying coating for anticorrosion and antibacterial applications. Laser processing is used to construct periodic micron-sized pillars for obtaining strong interface bonding between coating and substrate by mechanical interlocking effect, and as an ‘armor’, preventing the removal of the coating. The coating consists of epoxy resin (EP), hexadecyltrimethoxysilane (HDTMS) and γ-aminopropyltriethoxysilane treated Cu2O (KH550-Cu2O). The superhydrophobic surface can withstand various mechanical durability tests, such as multiple sandpaper abrasion and tape peeling cycles. It exhibits excellent corrosion inhibition efficiency (ηp > 99 %) on Mg alloy, Tinplate and Al alloy, which results from superhydrophobicity and organic coating. The superhydrophobicity endows surface with excellent antibacterial adhesion performance in a static liquid environment. The bactericidal activity of KH550-Cu2O can effectively inactivate the bacteria in contact with the surface and the free bacteria, providing excellent antibacterial ability in a dynamic liquid environment. It still exhibits good anticorrosion and antibacterial abilities after multiple mechanical abrasion cycles due to the outstanding mechanical durability. Moreover, it exhibits outstanding self-healing ability to plasma etching and oil contamination, self-cleaning ability under air and oil conditions, and chemical stability against acids and alkalis solution. All the above excellent performances promote its application in a wider range of fields.
基金The authors thank the National Natural Science Foundation of China(No.51775231)National Postdoctoral Program for Innovative Talents(BX20180123)+2 种基金China Postdoctoral Science Foundation(2018M641782)Scientific Research Project of Jilin Provincial Department of Education(JJKH20211117KJ)JLU Science and Technology Innovative Research Team(No.2017TD-04).
文摘In order to satisfy the needs of different applications and more complex intelligent devices,smart control of surface wettability will be necessary and desirable,which gradually become a hot spot and focus in the field of interface wetting.Herein,we review interfacial wetting states related to switchable wettability on superwettable materials,including several classical wetting models and liquid adhesive behaviors based on the surface of natural creatures with special wettability.This review mainly focuses on the recent developments of the smart surfaces with switchable wettability and the corresponding regulatory mechanisms under external stimuli,which is mainly governed by the transformation of surface chemical composition and geometrical structures.Among that,various external stimuli such as physical stimulation(temperature,light,electric,magnetic,mechanical stress),chemical stimulation(pH,ion,solvent)and dual or multi-triggered stimulation have been sought out to realize the regulation of surface wettability.Moreover,we also summarize the applications of smart surfaces in different fields,such as oil/water separation,programmable transportation,anti-biofouling,detection and delivery,smart soft robotic etc.Furthermore,current limitations and future perspective in the development of smart wetting surfaces are also given.This review aims to offer deep insights into the recent developments and responsive mechanisms in smart biomimetic surfaces with switchable wettability under external various stimuli,so as to provide a guidance for the design of smart surfaces and expand the scope of both fundamental research and practical applications.
基金Supported by the Planned Project for Science and Technology Development of Guilin City,China(20150117-2)the Special Fund for the Basic Research Operating Expenses Program of Public Welfare Research Institute Directly Subordinate to Guangxi,China(GCJB-16-18)
文摘In order to further optimize the cultivation and agronomic technology of Guilin Maojian tea gardens, the effects, efficiencies and costs of different farming methods and their effects on the physiochemical properties of tea garden soil were studied through the modification of the test sites with the non-farming land as the control. The results showed that human farming, mini-tiller farming and crawler tractor farming could improve the physical and chemical properties of soil. After farming, the soil had good water retention but low moisture content compared to the control group, while the soil bulk density and hardness value were significantly lower than those of the control, and the porosity of soil was significantly higher than that of contrast. With the passage of time, soil bulk density and hardness value gradually increased after farming, while the porosity of soil decreased gradually. There were great differences in the effects, efficiencies and costs of different farming methods. Crawler tractor had the best and most stable farming effect, and the operation efficiency was 10 times that of human farming while the cost was only 0.39 times of human farming. Therefore, it was feasible to adopt mini-tiller or crawler tractor to carry out mechanical farming of Guilin Maojian tea garden, which provided theoretical references for the soil property improvement using mechanical farming and was favorable for promoting the popularization of farming machines and the acceleration of mechanization of tea gardens. But for tea plantations that are intended to be mechanized, apart from the mechanical and technical personnel to be configured in place, the site conditions, planting modes and mechanical way reservation of tea garden should be planned accordingly. It is recommended to select flat or gentle slope for reclamation, and preference is given to non-sexual tea tree varieties with big line spacing over 180 cm long. Moreover, the main road construction should be more than 3.0 m, and trunk road 2.0 m or above. And isolation ditch and drain should be set between the tea garden and the surrounding mountain forests and farmland.
文摘The surface structures of heterogeneous catalysts significantly impact catalytic performance,especially for structure-sensitive reactions.In this study,we employed surface techniques such as low-energy ion scattering spectroscopy,X-ray photoelectron spectroscopy,and Fourier transform infrared spectroscopy with CO as a probe(CO-FTIR)to investigate the surface dynamics of Rh/Al_(2)O_(3)catalysts for propane dehydrogenation(PDH).We observed a notable induction process for PDH on Rh/Al_(2)O_(3)catalysts,marked by significant variations in propane conversion,methane,and propylene selectivities.These changes were attributed to substantial coke formation.Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy)and CO-FTIR revealed the coexistence of Rh nanoparticles,clusters,and single atoms on the surface.Through various dynamic quasi in-situ characterizations,we found that coke preferentially covered Rh clusters,thereby inhibiting C-C bond breaking and methane formation.Meanwhile,Rh single atoms were less affected by coke coverage and remained exposed as active and selective sites for PDH,favoring propylene production.This work underscores the sensitivity of PDH to the sizes of Rh species,with isolated Rh single atoms promoting propylene formation.
基金the National Key Research and Development Program of China(2021YFB1006200)Major Science and Technology Project of Henan Province in China(221100211200).Grant was received by S.Li.
文摘Adversarial distillation(AD)has emerged as a potential solution to tackle the challenging optimization problem of loss with hard labels in adversarial training.However,fixed sample-agnostic and student-egocentric attack strategies are unsuitable for distillation.Additionally,the reliability of guidance from static teachers diminishes as target models become more robust.This paper proposes an AD method called Learnable Distillation Attack Strategies and Evolvable Teachers Adversarial Distillation(LDAS&ET-AD).Firstly,a learnable distillation attack strategies generating mechanism is developed to automatically generate sample-dependent attack strategies tailored for distillation.A strategy model is introduced to produce attack strategies that enable adversarial examples(AEs)to be created in areas where the target model significantly diverges from the teachers by competing with the target model in minimizing or maximizing the AD loss.Secondly,a teacher evolution strategy is introduced to enhance the reliability and effectiveness of knowledge in improving the generalization performance of the target model.By calculating the experimentally updated target model’s validation performance on both clean samples and AEs,the impact of distillation from each training sample and AE on the target model’s generalization and robustness abilities is assessed to serve as feedback to fine-tune standard and robust teachers accordingly.Experiments evaluate the performance of LDAS&ET-AD against different adversarial attacks on the CIFAR-10 and CIFAR-100 datasets.The experimental results demonstrate that the proposed method achieves a robust precision of 45.39%and 42.63%against AutoAttack(AA)on the CIFAR-10 dataset for ResNet-18 and MobileNet-V2,respectively,marking an improvement of 2.31%and 3.49%over the baseline method.In comparison to state-of-the-art adversarial defense techniques,our method surpasses Introspective Adversarial Distillation,the top-performing method in terms of robustness under AA attack for the CIFAR-10 dataset,with enhancements of 1.40%and 1.43%for ResNet-18 and MobileNet-V2,respectively.These findings demonstrate the effectiveness of our proposed method in enhancing the robustness of deep learning networks(DNNs)against prevalent adversarial attacks when compared to other competing methods.In conclusion,LDAS&ET-AD provides reliable and informative soft labels to one of the most promising defense methods,AT,alleviating the limitations of untrusted teachers and unsuitable AEs in existing AD techniques.We hope this paper promotes the development of DNNs in real-world trust-sensitive fields and helps ensure a more secure and dependable future for artificial intelligence systems.
基金the National Natural Science Foundation of China(No.52105297,U22A20183)the Key Program for International Science and Technology Cooperation Projects of China(2024YFE0105500)+1 种基金Innovative Research Groups of the National Natural Science Foundation of China(No.52021003)JLU Science and Technology Innovative Research Team(No.2020TD-03).
文摘Water pollution remains one of the most pressing global challenges,driving an urgent need for advanced sustainable treatment materials.Derived from cellulose,the most abundant natural polymer on earth,cellulose aerogels(CAs)have become a highly promising candidate due to their unique three-dimensional porous structure,low density,high specific surface area,biodegradability and easy functionalization.Inspiration from the material and structural designs of natural biological systems has also effectively promoted the development and multifunctional applications of high-performance aerogels,positioning cellulose aerogels as a key area of research in the field of water treatment.This review systematically summarizes recent advancements in the design and functionalization strategies of cellulose aerogels specifically tailored for water pollution treatment.Firstly,it provides a comprehensive overview of CAs classification(native,regenerated,derivative,and composite),principal preparation methodologies including sol-gel processes and drying techniques(supercritical,freeze,and ambient pressure drying),and crucial functionalization approaches(such as surface chemical modification,incorporation of functional materials,and biomimetic structural design.).Subsequently,the review elaborates on the diverse applications of functionalized CAs in tackling various water contaminants,including efficient oil-water separation,removal of heavy metal ions,adsorption of organic dyes,treatment of emerging pollutants like microplastics,and solar-driven water desalination.The underlying pollutant removal mechanisms are analyzed in depth,encompassing physical adsorption,size sieving,interfacial wettability control,electrostatic interactions,coordination/ion exchange,photothermal conversion,catalytic degradation,and synergistic effects.This review provides insights for developing advanced cellulose-based aerogels,while highlighting current challenges and future perspectives in water treatment.
基金the National Natural Science Foundation of China(Grant No.82301025)the Talents Introduction of Guangdong Provincial People’s Hospital(Grant Nos.KY0120220255,3227100558,8237030185)+4 种基金Guangzhou Municipal Science and Technology Bureau(Grant No.2024A04J4888)the National Key Research and Development Program of China(Grant No.2023YFC2413600)the Natural Science Foundation of Guangdong Province(Grant No.2022A1515110916)the GJYC pro-gram of Guangzhou(Grant No.2024D03J0004)the National Nat-ural Science Foundation of China(Grant No.52433010).
文摘The periosteum,a fibrous tissue membrane covering bone surfaces,is critical to osteogenesis and angiogenesis in bone reconstruction.Artificial periostea have been widely developed for bone defect repair,but most of these are lacking of periosteal bioactivity.Herein,a biomimetic periosteum(termed PEC-Apt-NP-Exo)is prepared based on an electrospun membrane combined with engineered exosomes(Exos).The electrospun membrane is fabricated using poly(ε-caprolactone)(core)-periosteal decellularized extracellular matrix(shell)fibers via coaxial elec-trospinning,to mimic the fibrous structure,mechanical property,and tissue microenvironment of natural periosteum.The engineered Exos derived from M2 macrophages are functionalized by surface modification of bone marrow mesenchymal stem cell(BMSC)-specific aptamers to further enhance cell recruitment,immuno-regulation,and angiogenesis in bone healing.The engineered Exos are covalently bonded to the electrospun membrane,to achieve rich loading and long-term effects of Exos.In vitro experiments demonstrate that the biomimetic periosteum promotes BMSC migration and osteogenic differentiation via Rap1/PI3K/AKT signaling pathway,and enhances vascular endothelial growth factor secretion from BMSCs to facilitate angiogenesis.In vivo studies reveal that the biomimetic periosteum promotes new bone formation in large bone defect repair by inducing M2 macrophage polarization,endogenous BMSC recruitment,osteogenic differentiation,and vascu-larization.This research provides valuable insights into the development of a multifunctional biomimetic peri-osteum for bone regeneration.
基金the National Natural Science Foundation of China(Nos.22379075,22471114,U23A20528)the Group Project of Developing Inner Mongolia through Talents from the Talents Work Leading Group under the CPC Inner Mongolia Autonomous Regional Committee(No.2025TEL04)+2 种基金Natural Science Foundation of Inner Mongolia Autonomous Region(No.2024LHMS02011)the Innovative Research Team in Universities of Inner Mongolia Autonomous Region(No.NMGIRT2212)Basic Scientific Research Funds of Universities directly under the Inner Mongolia Autonomous Region(Nos.ZTY2025013 and JY20240076)for financial support。
文摘Calcium carbide,a bulky and cheap raw chemical,is traditionally depolymerized by water to release acetylene,allowing the downstream organic transformation.In this study,hydrogen sulfide(H_(2)S),an industrial waste gas,has been exploited to depolymerize calcium carbide,which represents a strategy for the comprehensive utilization of both hydrogen sulfide and calcium carbide.As a proof of concept,a three-component condensation reaction was established to prepare thioamides directly from hydrogen sulfide and calcium carbide in high yields.Leveraging the unique properties of thioamides that possess both nucleophilic sulfur and electrophilic carbon sites,a series of novel tandem reactions were further developed to construct structurally diverse heterocyclic compounds.Our strategy not only provides a new chemical pathway for calcium carbide depolymerization,but also offers a solution for the utilization of hazardous hydrogen sulfide gas.More importantly,this approach facilitates the comprehensive and sustainable utilization of the calcium carbide resource.
基金This work was supported by the Singapore Ministry of Education(MOE)Tier 3 grant(MOE2017-T3-1-001),NRF grant(MOH-000926),A*STAR research grant(SERC-A18A5b0056)PUB Singapore's National Water Agency grant(PUB-1804-0082).
文摘Recent years have witnessed significant progress in quantum communication and quantum internet with the emerging quantum photonic chips,whose characteristics of scalability,stability,and low cost,flourish and open up new possibilities in miniaturized footprints.Here,we provide an overview of the advances in quantum photonic chips for quantum communication,beginning with a summary of the prevalent photonic integrated fabrication platforms and key components for integrated quantum communication systems.We then discuss a range of quantum communication applications,such as quantum key distribution and quantum teleportation.Finally,the review culminates with a perspective on challenges towards high-performance chip-based quantum communication,as well as a glimpse into future opportunities for integrated quantum networks.
基金National Natural Science Foundation of China(11504435,61975062)National Key Research and Development Program of China(2019YFB2205202)Innovation Fund of WNLO.
文摘Multimode waveguide bend is one of the key components for realizing high-density mode-division multiplexing systems on chip.However,the reported multimode waveguide bends are either large,bandwidth-limited or fabrication-complicated,which hinders their applications in future high-density multimode photonic circuits.Here we propose a compact multimode waveguide bend supporting four TE modes simply by shape-optimizing with transformation optics.The shape of the waveguide is optimized in the virtual space with gradient distribution of the refractive index,so that the scattering loss and intermode cross talk are well suppressed.After conformal mapping back into the physical space,a compact(effective radius of 17μm)multimode bending waveguide is obtained.Simulations show that the proposed multimode waveguide bend has little loss(<0.1 dB)and low cross talk(<−20 dB)throughout an ultrabroad wavelength range of 1.16–1.66μm.We also fabricated the shape-optimized multimode bending waveguide on a silicon-on-insulator wafer.At 1550 nm wavelength,the measured excess losses for the four lowest-order TE modes are less than 0.6 dB,and the intermode cross talks are all below−17 dB.Our study paves the way for realizing high-density and large-scale multimode integrated optical circuits for optical interconnect.
文摘Gold nanoparticles （Au NPs） have been widely utilized in biomedical appli- cations owing to their attractive features and biocompatibility, which greatly increase the risk of humans＂ being exposed to Au NPs, including pregnant women. In contrast to mature cells, embryos are more susceptible to outside disruptive stimuli. Nonetheless, a possible inhibitory effect of nanomaterials on embryonic development is usually ignored as long as the NPs do not have significant cytotoxic effects. According to our results, a minimal ＂nontoxic＂ concentration of Au NPs during early pregnancy can have lethal inhibitory effects on embryos in vivo and in vitro. We conducted important experiments on the influence of Au NPs on embryonic development and found that Au NPs can disturb embryonic development in a size- and concentration-dependent manner. Au NPs of 15 nm in diameter downregulated the expression pattern of distinct germ layer markers both at mRNA and protein levels; this action prevented differentiation of all three embryonic germ layers. Consequentl~ fetal resorption was observed. Our work reveals the impact of Au NPs on embryonic development and will provide an important guidance and serve as a reference for biomedical applications of Au NPs with minimal side effects.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11775110, and 11690034)the European Union’s Horizon 2020 Research and Innovation (RISE) Programme (Grant No. 644121)the Priority Academic Program Development for Jiangsu Higher Education Institutions (PAPD)
文摘A bounce universe model with a scale-invariant and stable spectrum of primordial density perturbations was constructed using a consistent truncation of the D-brane dynamics from Type IIB string theory. A coupling was introduced between the tachyon field and the adjoint Higgs field on the D3-branes to lock the tachyon at the top of its potential hill and to model the bounce process,which is known as the Coupled Scalar and Tachyon Bounce(CSTB) Universe. The CSTB model has been shown to be ghost free,and it fulfils the null energy condition; in addition, it can also solve the Big Bang cosmic singularity problem. In this paper we conduct an extensive follow-up study of the parameter space of the CSTB model. In particular we are interested in the parameter values that can produce a single bounce to arrive at a radiation-dominated universe. We further establish that the CSTB universe is a viable alternative to inflation, as it can naturally produce a sufficient number of e-foldings in the locked inflation epoch and in the post-bounce expansion to overcome the four fundamental limitations of the Big Bang cosmology, which are flatness, horizon,homogeneity and singularity, resulting in a universe of the current size.
基金Defense Industrial Technology Development Program,Grant/Award Number:JCKY2019110D024JLU Science and Technology Innovative Research Team,Grant/Award Number:2020TD-03Scientific Research Project of Jilin Provincial Department of Education,Grant/Award Number:JJKH20211117KJ。
文摘A fluorine-free and multifunctional superhydrophobic coating(r-MSC)was prepared by the one-step spraying method.The coating had superhydrophobic and low-adhesion properties with the water contact angle of 161.5°�1°and the sliding angle of 3.2°�0.5°.It could be prepared by spraying while maintaining superhydrophobic surface characteristics on any substrates.The coating owed outstanding mechanical durability and chemical stability.Moreover,the coating also possessed the ability of self-cleaning,anti-fouling,anti-icing,and flame retardant ability.Importantly,the presence of multifunc-tional coating endowed the substrate with both water-resistant and fireproof properties.Besides,it also showed excellent oil-water separation ability,which presented the oil-water separation efficiency of over 90%for different types of oils after 10 separation cycles.Furthermore,the coating could improve corrosion inhibition performance and the corrosion current density was reduced by two orders of magnitude from the polarization curve.The r-MSC had the advantages of simple preparation,fluorine-free,environ-mentally friendly and appropriate for large-area fabrication,which could be applied to various fields.
