Functional materials synthesized from bio-based building blocks are fascinating and challenging in the fields of chemistry and materials science.Herein,we present a versatile strategy for synthesizing bio-based stimul...Functional materials synthesized from bio-based building blocks are fascinating and challenging in the fields of chemistry and materials science.Herein,we present a versatile strategy for synthesizing bio-based stimulus-responsive polymers derived from itaconic acid(IA).Bearing an azobenzene-containing side chain,the IA-based epoxy polymer exhibited both photoresponsiveness and acid/base-stimulus responsiveness.With controllable manipulation of the stress field of the wrinkling IA-polymer film via the stress relaxation effect resulting from the reversible cis-trans isomerization of the azobenzene moieties or solvent-induced swelling of the film,various tailor-made patterned wrinkling surfaces were conveniently fabricated.More importantly,the azobenzene protonation/deprotonation yields a reversible visual color transformation between pale yellow and purple in the film,which allows these IA-based polymer-coated surfaces to be utilized as rewritable information storage media.Various elegant pattern information can be acid-printed and base-erased(within 10 s)for multiple cycles and legible for over one day under laboratory conditions.Notably,the aforementioned dual-stimulus responsiveness of the IA-based polymer film enables its surface to be applied in information encryption.This study not only paves a new avenue for the convenient fabrication of stimulus-responsive surfaces but also sheds light on the development of functional polymers through green engineering.展开更多
Global warming induced by increased CO_(2) has caused marked changes in the ocean.Previous estimates of ocean salinity change in response to global warming have considerable ambiguity,largely attributable to the diver...Global warming induced by increased CO_(2) has caused marked changes in the ocean.Previous estimates of ocean salinity change in response to global warming have considerable ambiguity,largely attributable to the diverse sensitivities of surface fluxes.This study utilizes data from the Flux-Anomaly-Forced Model Intercomparison Project to investigate how ocean salinity responds to perturbations of surface fluxes.The findings indicate the emergence of a sea surface salinity(SSS)dipole pattern predominantly in the North Atlantic and Pacific fresh pools,driven by surface flux perturbations.This results in an intensification of the“salty gets saltier and fresh gets fresher”SSS pattern across the global ocean.The spatial pattern amplification(PA)of SSS under global warming is estimated to be approximately 11.5%,with surface water flux perturbations being the most significant contributor to salinity PA,accounting for 8.1% of the change after 70 years in experiments since pre-industrial control(piControl).Notably,the zonal-depth distribution of salinity in the upper ocean exhibits lighter seawater above the denser water,with bowed isopycnals in the upper 400 m.This stable stratification inhibits vertical mixing of salinity and temperature.In response to the flux perturbations,there is a strong positive feedback due to consequent freshening.It is hypothesized that under global warming,an SSS amplification of 7.2%/℃ and a mixed-layer depth amplification of 12.5%/℃ will occur in the global ocean.It suggests that the salinity effect can exert a more stable ocean to hinder the downward transfer of heat,which provides positive feedback to future global warming.展开更多
Bacterial adhesion and biofilm formation impose a heavy burden on the medical system. Bacterial adhesion on implant materials would induce inflammation and result in implant failure. The adhesion of bacteria on food-p...Bacterial adhesion and biofilm formation impose a heavy burden on the medical system. Bacterial adhesion on implant materials would induce inflammation and result in implant failure. The adhesion of bacteria on food-processing and handling equipment may lead to food-borne illness. To reduce and even prevent bacterial adhesion, some bacterial anti-adhesion surface designs have been developed. However,the effect of some surface properties(including surface patterning, roughness and wettability) on bacterial adhesion has not been systematically summarized. In this review, a comprehensive overview of bacterial anti-adhesion surface design is presented. Modifying the surface pattern and roughness could reduce the contact area between bacteria and surfaces to weaken the initial adhesion force. Fabricating superhydrophobic surface or modifying hydrophilic functional groups could hinder the bacterial adhesion. The analysis and discussion about influencing factors of bacterial anti-adhesion surfaces provide basic guidelines on antibacterial surface design for future researches.展开更多
We demonstrate a process to achieve selective surface metallization of ZrO_(2)ceramics using ultrasound technology in atmospheric environments at 350℃,which bestows good weldability of ZrO_(2)to achieve rapid and rel...We demonstrate a process to achieve selective surface metallization of ZrO_(2)ceramics using ultrasound technology in atmospheric environments at 350℃,which bestows good weldability of ZrO_(2)to achieve rapid and reliable connections with other metals as well as ceramic materials.The challenge is that brazing or diffusion welding processes to accomplish metallurgical connections for ZrO_(2) typically require holding at elevated temperatures for minutes to hours,while the selective ultrasonic metallization process requires only a few seconds of processing without the application of covering films or solder resists.In this study,the selected Sn-2Ti alloy could effectively wet and spread on ZrO_(2)substrate under ultrasonication,and continuous interphase layers were rapidly formed in situ between ZrO_(2)and Sn-2Ti.The bonding strength for the ZrO_(2)/Sn-2Ti interface was well established with the highest shear strength of 37.1 MPa,and the fracture location occurred at the filler metal.The interfacial reaction layer thickened remarkably with the prolongation of sonication,accompanied by the partial crystallization of amorphous TiO and the formation of irregularly striped Ti_(11.31)Sn_(3)O_(10)nanocrystals.展开更多
The undesirable dendrite growth induced by non-planar zinc(Zn)deposition and low Coulombic efficiency resulting from severe side reactions have been long-standing challenges for metallic Zn anodes and substantially im...The undesirable dendrite growth induced by non-planar zinc(Zn)deposition and low Coulombic efficiency resulting from severe side reactions have been long-standing challenges for metallic Zn anodes and substantially impede the practical application of rechargeable aqueous Zn metal batteries(ZMBs).Herein,we present a strategy for achieving a high-rate and long-cycle-life Zn metal anode by patterning Zn foil surfaces and endowing a Zn-Indium(Zn-In)interface in the microchannels.The accumulation of electrons in the microchannel and the zincophilicity of the Zn-In interface promote preferential heteroepitaxial Zn deposition in the microchannel region and enhance the tolerance of the electrode at high current densities.Meanwhile,electron aggregation accelerates the dissolution of non-(002)plane Zn atoms on the array surface,thereby directing the subsequent homoepitaxial Zn deposition on the array surface.Consequently,the planar dendrite-free Zn deposition and long-term cycling stability are achieved(5,050 h at 10.0 mA cm^(−2) and 27,000 cycles at 20.0 mA cm^(−2)).Furthermore,a Zn/I_(2) full cell assembled by pairing with such an anode can maintain good stability for 3,500 cycles at 5.0 C,demonstrating the application potential of the as-prepared ZnIn anode for high-performance aqueous ZMBs.展开更多
Direct Laser Interference Patterning(DLIP)is used to texture current collector foils in a roll-to-roll process using a high-power picosecond pulsed laser system operating at either fundamental wavelength of 1064 nm or...Direct Laser Interference Patterning(DLIP)is used to texture current collector foils in a roll-to-roll process using a high-power picosecond pulsed laser system operating at either fundamental wavelength of 1064 nm or 2nd harmonic of 532 nm.The raw beam having a diameter of 3 mm@1/e^(2) is shaped into an elongated top-hat intensity profile using a diffractive so-called FBS■-L element and cylindrical telescopes.The shaped beam is split into its diffraction orders,where the two first orders are parallelized and guided into a galvanometer scanner.The deflected beams inside the scan head are recombined with an F-theta objective on the working position generating the interference pattern.The DLIP spot has a line-like interference pattern with about 15μm spatial period.Laser fluences of up to 8 J cm^(-2) were achieved using a maximum pulse energy of 0.6 mJ.Furthermore,an in-house built roll-to-roll machine was developed.Using this setup,aluminum and copper foil of 20μm and 9μm thickness,respectively,could be processed.Subsequently to current collector structuring coating of composite electrode material took place.In case of lithium nickel manganese cobalt oxide(NMC 622)cathode deposited onto textured aluminum current collector,an increased specific discharge capacity could be achieved at a C-rate of 1℃.For the silicon/graphite anode material deposited onto textured copper current collector,an improved rate capability at all C-rates between C/10 and 5℃ was achieved.The rate capability was increased up to 100%compared to reference material.At C-rates between C/2 and 2℃,the specific discharge capacity was increased to 200 mAh g^(-1),while the reference electrodes with untextured current collector foils provided a specific discharge capacity of 100 m Ah g^(-1),showing the potential of the DLIP technology for cost-effective production of battery cells with increased cycle lifetime.展开更多
Cell behaviors are regulated by a dynamic and complex environment characterized by biophysical,mechanical and biochemical properties.However,most works regulate cell behaviors under static conditions or by external fa...Cell behaviors are regulated by a dynamic and complex environment characterized by biophysical,mechanical and biochemical properties.However,most works regulate cell behaviors under static conditions or by external factors.To control cell adhesion and proliferation with a dynamic and mechanical environment,we pattern the surface on self-healing copolymer P(MMA/nBA).The copolymer P(MMA/nBA)with the composition of 48/52(MMA/nBA)recovers nearly 100%of its original tensile strains after 86 h of recovery from deformation.The physical patterns on P(MMA/nBA)film are obtained over large areas and the size of the hole and the width of connecting bar are in line with the copper grid specifications.The patterned surface tends to be fiat after 12 h with almost 75%-80%recovery.Compared with cell incubation on polystyrene fiat and patterned surface of P(MMA/nBA)film without self-healing capability,the number and morphology of cells are well manipulated on the patterned surface of self-healing P(MMA/nBA)film.This approach provides a convenient method for dynamically regulating the cell behaviors on the surface of self-healing materials without chemical or biological modifications.展开更多
Polymer-based materials with patterned functional particles have been used to develop smart devices with multiple functionalities.This paper presents a novel method to pattern microscale particles into biocompatible p...Polymer-based materials with patterned functional particles have been used to develop smart devices with multiple functionalities.This paper presents a novel method to pattern microscale particles into biocompatible polyethylene glycol diacrylate(PEGDA)fluid through a designed surface acoustic wave(SAW)device with slanted-finger interdigital transducers(SFITs).By applying signals of different frequencies,the SFITs can excite SAWs with various wavelengths to pattern the microscale particles.The structural design and working principle of the SAW device with SFITs are firstly presented.To investigate the generation of standing SAWs and pressure field distributions of the SAW device with SFITs,a numerical model was developed.Simulation results showed that different strip-shape patterned pressure fields can be generated,and the period and width of adjacent strips can be adjusted by changing the frequencies of the excitation signals.Experiments were performed to verify that the microscale particles in the PEGDA solution can be successfully patterned into strip-shape patterns with various positions,periods,and widths.The results obtained in this study demonstrate that the developed method of using an SAW device with SFITs can be used for tunable patterning of microscale particles in solutions,and shows great potential for biomedical and microfluidic applications.展开更多
Utilizing superwettability micro/nanostructures to enhance the condensation heat transfer(CHT)performance of engineering materials has attracted great interest due to its values in basic research and technological inn...Utilizing superwettability micro/nanostructures to enhance the condensation heat transfer(CHT)performance of engineering materials has attracted great interest due to its values in basic research and technological innovations.Currently,exploring facile micro/nanofabrication approaches to create high-efficiency CHT surfaces has been one of research hotspots.In this work,we propose and demonstrate a type of new superwettability hybrid surface for high-efficiency CHT,which consists of superhydrophobic nanoneedle arrays and triangularly-patterned superhydrophilic microdots(SMDs).Such hybrid surface can be fabricated by the facile growth of densely-packed ZnO nanoneedles on the Zn-electroplated copper surface followed by fluorosilane modification and mask-assisted photodegradation.Through regulating the diameters and interspaces of SMDs,we obtain the optimized triangularly-patterned hybrid surface,which shows 42.7%higher CHT coefficient than the squarely-patterned hybrid surface and 58.5%higher CHT coefficient than the superhydrophobic surface.The key of such hybrid surface design is to considerably increase CHT coefficient brought about by SMD-triggered drop sweeping at the cost of slightly reducing heat transfer area of superhydrophobic functional zone for drop jumping.Such new strategy helps develop advanced CHT surfaces for high-efficiency electronic cooling and energy utilization.展开更多
A high humidity-resistant,dual mechanical responsive,and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane(PDMS)substrate with a thin film consisting of 90 wt%poly(vinyl butyral)(PVB)...A high humidity-resistant,dual mechanical responsive,and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane(PDMS)substrate with a thin film consisting of 90 wt%poly(vinyl butyral)(PVB)and 10 wt%hydroxypropyl cellulose(HPC)has been reported.The wrinkling system exhibited significant optical tuning from transparent to opaque states with 50%changes in transmittance,which was achieved through the dual mechanical modes of pre-stretching and releasing processes or bending.Upon exposure to ethanol vapor or a re-flattening process,wrinkles can be erased,yielding a transparent state.Consequently,the wrinkling system could be reversibly switched between transparency and opacity for 1000 cycles with marginal changes in the optical performance.Owing to the insolubility of PVB in water,the wrinkling patterns exhibited excellent durability in high-humidity environments(relative humidity(RH)=99%).Furthermore,the smart encryption device is also demonstrated via mechano-controlled surface topography by patterning the wrinkling system,suggesting potential applications of the designed structure in smart windows,anti-counterfeiting,dynamic display,optical information encryption,and rewritable surfaces.展开更多
The present work deals with the numerical study of the two-phase flow pattern and heat transfer characteristics of single-loop pulsating heat pipes(PHPs)under three modified surfaces(superhydrophilic evaporation secti...The present work deals with the numerical study of the two-phase flow pattern and heat transfer characteristics of single-loop pulsating heat pipes(PHPs)under three modified surfaces(superhydrophilic evaporation section paired with superhydrophilic,superhydrophobic,and hybrid condensation section).The Volume of Fluid(VOF)model was utilized to capture the phase-change process within the PHPs.The study also evaluated the influence of surface wettability on fluid patterns and thermo-dynamic heat transfer performance under various heat fluxes.The results indicated that the effective nucleation and detachment of droplets are critical factors influencing the thermal performance of the PHPs.The overall heat transfer performance of the superhydrophobic surface was significantly improved at low heat flux.Under medium to high heat flux,the superhydrophilic condensation section exhibits a strong oscillation effect and leads to the thickening of the liquid film.In addition,the hybrid surface possesses the heat transfer characteristics of both superhydrophilic and superhydrophobic walls.The hybrid condensation section exhibited the lowest thermal resistance by 0.45 K/W at the heat flux of 10731 W/m^(2).The thermal resistance is reduced by 13.1%and 5.4%,respectively,compared to the superhydrophobic and superhydrophilic conditions.The proposed surface-modification method for achieving highly efficient condensation heat transfer is helpful for the design and operation of device-cooling components.展开更多
Fractures in rock strata serve as flow pathways for gas flow.The undulation of fracture channels can influence the guidance of gas flow.In this context,four-point bending experiments on prefabricated fractured rocks a...Fractures in rock strata serve as flow pathways for gas flow.The undulation of fracture channels can influence the guidance of gas flow.In this context,four-point bending experiments on prefabricated fractured rocks at different angles under stable stepped loading stress.The experiment results clarified the evolutionary law that the undulation degree of the rock tensile fracture surface is separated by an initial fracture angle of 45°.The high undulation intervals were less than 45°,whereas the low undulation intervals were more than 45°.Furthermore,the relative undulation degree,undulation frequency,and matching degree of the fracture surface were quantified.The relationship between the change in fracture surface undulation and gas flow guidance was established.Based on this,the stability,tortuosity,and uniformity of the gas flow in the fracture channel were quantitatively characterized.Subsequently,numerical models of the fracture channels were constructed to validate the indices proposed in this study.The results of the study clarified the influence of different initial fracture angles on the undulation changes of fracture surfaces,and established the relationship between these changes and gas flow,which is conducive to understanding the role of internal fracture channels in rocks in guiding the gas flow process.展开更多
Defect inspection of specular curved surface is a challenging job. Taking steel balls for example, a new method based on reflected pattern integrity recognition is put forward. The specular steel ball surfac...Defect inspection of specular curved surface is a challenging job. Taking steel balls for example, a new method based on reflected pattern integrity recognition is put forward. The specular steel ball surface will totally reflect the patterns when it is placed inside a dome-shaped light source, whose inner wall is modified by patterns with certain regular. Distortion or intermittence of reflected pattern will occur at the defective part, which indicates the pattern has lost its integrity. Based on the integrity analysis of reflected pattern images？ surface defects can be revealed. In this paper, a set of concentric circles are used as the pattern and an image processing algorithm is customized to extract the surface defects. Results show that the proposed method is effective for the specular curved surface defect inspection展开更多
In order to investigate the effect of Thiobacillusferrooxidans on the oxidation of pyrite, two parallel experiments, which employed H2SO4 solutions and acidic solutions inoculated with ThiobaciUus ferrooxidans, were d...In order to investigate the effect of Thiobacillusferrooxidans on the oxidation of pyrite, two parallel experiments, which employed H2SO4 solutions and acidic solutions inoculated with ThiobaciUus ferrooxidans, were designed and carried out at 30℃. The initial pH of the two solutions was adjusted to 2.5 by dropwise addition of concentrated sulphuric acid. The surfaces of pyrite before exposure to leaching solutions and after exposure to the H2SO4 solutions and acidic solutions inoculated with Thiobacillus ferrooxidans were observed by scanning electron microscopy （SEM）. There were a variety of erosion patterns by Thiobacillusferrooxidans on the bio-leached pyrite surfaces. A conclusion can be drawn that the oxidation of pyrite might have been caused by erosion of the surfaces. Attachment of the bacteria to pyrite surfaces resulted in erosion pits, leading to the oxidation of pyrite. It is possible that the direct mechanism plays the most important role in the oxidation of pyrite. The changes in iron ion concentrations of both the experimental solutions with time suggest that ThiobaciUus ferrooxidans can enhance greatly the oxidation of pyrite.展开更多
The spatial patterns and regional-scale surface air temperature （SAT） changes during the last millennium,as well as the variability of the East Asian summer monsoon （EASM） were simulated with a low-resolution vers...The spatial patterns and regional-scale surface air temperature （SAT） changes during the last millennium,as well as the variability of the East Asian summer monsoon （EASM） were simulated with a low-resolution version of Flexible Global Ocean-Atmosphere-Land-Sea-ice （FGOALS-gl） model.The model was driven by both natural and anthropogenic forcing agents.Major features of the simulated past millennial Northern Hemisphere （NH） mean SAT variations,including the Medieval Climate Anomaly （MCA）,the Little Ice Age （LIA） and the 20th Century Warming （20CW）,were generally consistent with the reconstructions.The simulated MCA showed a global cooling pattern with reference to the 1961-90 mean conditions,indicating the 20CW to be unprecedented over the last millennium in the simulation.The LIA was characterized by pronounced coldness over the continental extratropical NH in both the reconstruction and the simulation.The simulated global mean SAT difference between the MCA and LIA was 0.14°C,with enhanced warming over high-latitude NH continental regions.Consistencies between the simulation and the reconstruction on regional scales were lower than those on hemispheric scales.The major features agreed well between the simulated and reconstructed SAT variations over the Chinese domain,despite some inconsistency in details among different reconstructions.The EASM circulation during the MCA was stronger than that during the LIA The corresponding rainfall anomalies exhibited excessive rainfall in the north but deficient rainfall in the south.Both the zonal and meridional thermal contrast were enhanced during the MCA.This temperature anomaly pattern favored a stronger monsoon circulation.展开更多
Impervious surfaces are the result of urbanization that can be explicitly quantified, managed and controlled at each stage of land development. It is a very useful environmental indicator that can be used to measure t...Impervious surfaces are the result of urbanization that can be explicitly quantified, managed and controlled at each stage of land development. It is a very useful environmental indicator that can be used to measure the impacts of urbanization on surface runoff, water quality, air quality, biodiversity and rnicroclimate. Therefore, accurate estimation of impervious surfaces is critical for urban environmental monitoring, land management, decision-making and urban planning. Many approaches have been developed to estimate surface imperviousness, using remotely sensed data with various spatial resolutions. However, few studies, have investigated the effects of spatial resolution on estimating surface imperviousness. We compare medium-resolution Landsat data with high-resolution SPOT images to quantify the imperviousness in Beijing, China. The results indicated that the overall 91% accuracy of estimates of imperviousness based on TM data was considerably higher than the 81% accuracy of the SPOT data. The higher resolution SPOT data did not always predict the imperviousness of the land better than the TM data. At the whole city level, the TM data better predicts the percentage cover of impervious surfaces. At the sub-city level, however, the ring belts from the central core to the urban-rural peripheral, the SPOT data may better predict the imperviousness. These results highlighted the need to combine multiple resolution data to quantify the percentage of imperviousness, as higher resolution data do not necessarily lead to more accurate estimates. The methodology and results in this study can be utilized to identify the most suitable remote sensing data to quickly and efficiently extract the pattern of the impervious land, which could provide the base for further study on many related urban environmental problems.展开更多
On the basis of field investigations, observations andexperimental data combined with environmental monitoring information,the status and the spatial and temporal patterns of surface waterpollution over the past ten y...On the basis of field investigations, observations andexperimental data combined with environmental monitoring information,the status and the spatial and temporal patterns of surface waterpollution over the past ten years in the Yangtze River Delta havebeen assessed. The water quality of large rivers is still very goodbut most of the medium-sized and small rivers have been veryseriously polluted. The appearance of black and odorous conditions inrivers in the urban areas has increased due to serious pollution byorganic matter with consequent high oxygen demand. Annual increasesin N and P concentrations in lakes have accelerated eutrophication.The water quality of river sin small towns is rapidly deteriorating.The main sources of surface water pollution include industrial anddomestic sewage, animal manures, chemical fertilizers in farmland,and polluted sediments in rivers and lakes.展开更多
基金supported by the Natural Science Foundation of Shandong Province(No.ZR2022MB034)。
文摘Functional materials synthesized from bio-based building blocks are fascinating and challenging in the fields of chemistry and materials science.Herein,we present a versatile strategy for synthesizing bio-based stimulus-responsive polymers derived from itaconic acid(IA).Bearing an azobenzene-containing side chain,the IA-based epoxy polymer exhibited both photoresponsiveness and acid/base-stimulus responsiveness.With controllable manipulation of the stress field of the wrinkling IA-polymer film via the stress relaxation effect resulting from the reversible cis-trans isomerization of the azobenzene moieties or solvent-induced swelling of the film,various tailor-made patterned wrinkling surfaces were conveniently fabricated.More importantly,the azobenzene protonation/deprotonation yields a reversible visual color transformation between pale yellow and purple in the film,which allows these IA-based polymer-coated surfaces to be utilized as rewritable information storage media.Various elegant pattern information can be acid-printed and base-erased(within 10 s)for multiple cycles and legible for over one day under laboratory conditions.Notably,the aforementioned dual-stimulus responsiveness of the IA-based polymer film enables its surface to be applied in information encryption.This study not only paves a new avenue for the convenient fabrication of stimulus-responsive surfaces but also sheds light on the development of functional polymers through green engineering.
基金supported by the Laoshan Laboratory[grant number LSKJ202202403]the National Natural Science Foundation of China[grant number 42030410]+1 种基金additionally supported by the Startup Foundation for Introducing Talent of NUISTJiangsu Innovation Research Group[grant number JSSCTD202346]。
文摘Global warming induced by increased CO_(2) has caused marked changes in the ocean.Previous estimates of ocean salinity change in response to global warming have considerable ambiguity,largely attributable to the diverse sensitivities of surface fluxes.This study utilizes data from the Flux-Anomaly-Forced Model Intercomparison Project to investigate how ocean salinity responds to perturbations of surface fluxes.The findings indicate the emergence of a sea surface salinity(SSS)dipole pattern predominantly in the North Atlantic and Pacific fresh pools,driven by surface flux perturbations.This results in an intensification of the“salty gets saltier and fresh gets fresher”SSS pattern across the global ocean.The spatial pattern amplification(PA)of SSS under global warming is estimated to be approximately 11.5%,with surface water flux perturbations being the most significant contributor to salinity PA,accounting for 8.1% of the change after 70 years in experiments since pre-industrial control(piControl).Notably,the zonal-depth distribution of salinity in the upper ocean exhibits lighter seawater above the denser water,with bowed isopycnals in the upper 400 m.This stable stratification inhibits vertical mixing of salinity and temperature.In response to the flux perturbations,there is a strong positive feedback due to consequent freshening.It is hypothesized that under global warming,an SSS amplification of 7.2%/℃ and a mixed-layer depth amplification of 12.5%/℃ will occur in the global ocean.It suggests that the salinity effect can exert a more stable ocean to hinder the downward transfer of heat,which provides positive feedback to future global warming.
基金supported by the National Natural Science Foundation of China (52003028)Fundamental Research Funds for the Central Universities (FRF-GF-20-06B)
文摘Bacterial adhesion and biofilm formation impose a heavy burden on the medical system. Bacterial adhesion on implant materials would induce inflammation and result in implant failure. The adhesion of bacteria on food-processing and handling equipment may lead to food-borne illness. To reduce and even prevent bacterial adhesion, some bacterial anti-adhesion surface designs have been developed. However,the effect of some surface properties(including surface patterning, roughness and wettability) on bacterial adhesion has not been systematically summarized. In this review, a comprehensive overview of bacterial anti-adhesion surface design is presented. Modifying the surface pattern and roughness could reduce the contact area between bacteria and surfaces to weaken the initial adhesion force. Fabricating superhydrophobic surface or modifying hydrophilic functional groups could hinder the bacterial adhesion. The analysis and discussion about influencing factors of bacterial anti-adhesion surfaces provide basic guidelines on antibacterial surface design for future researches.
基金financially supported by the National Natural Science Foundation of China(No.51805111).
文摘We demonstrate a process to achieve selective surface metallization of ZrO_(2)ceramics using ultrasound technology in atmospheric environments at 350℃,which bestows good weldability of ZrO_(2)to achieve rapid and reliable connections with other metals as well as ceramic materials.The challenge is that brazing or diffusion welding processes to accomplish metallurgical connections for ZrO_(2) typically require holding at elevated temperatures for minutes to hours,while the selective ultrasonic metallization process requires only a few seconds of processing without the application of covering films or solder resists.In this study,the selected Sn-2Ti alloy could effectively wet and spread on ZrO_(2)substrate under ultrasonication,and continuous interphase layers were rapidly formed in situ between ZrO_(2)and Sn-2Ti.The bonding strength for the ZrO_(2)/Sn-2Ti interface was well established with the highest shear strength of 37.1 MPa,and the fracture location occurred at the filler metal.The interfacial reaction layer thickened remarkably with the prolongation of sonication,accompanied by the partial crystallization of amorphous TiO and the formation of irregularly striped Ti_(11.31)Sn_(3)O_(10)nanocrystals.
基金supported by the National Research Foundation of Korea Grant funded by the Korean government(MSIP)(No.2018R1A6A1A03025708).
文摘The undesirable dendrite growth induced by non-planar zinc(Zn)deposition and low Coulombic efficiency resulting from severe side reactions have been long-standing challenges for metallic Zn anodes and substantially impede the practical application of rechargeable aqueous Zn metal batteries(ZMBs).Herein,we present a strategy for achieving a high-rate and long-cycle-life Zn metal anode by patterning Zn foil surfaces and endowing a Zn-Indium(Zn-In)interface in the microchannels.The accumulation of electrons in the microchannel and the zincophilicity of the Zn-In interface promote preferential heteroepitaxial Zn deposition in the microchannel region and enhance the tolerance of the electrode at high current densities.Meanwhile,electron aggregation accelerates the dissolution of non-(002)plane Zn atoms on the array surface,thereby directing the subsequent homoepitaxial Zn deposition on the array surface.Consequently,the planar dendrite-free Zn deposition and long-term cycling stability are achieved(5,050 h at 10.0 mA cm^(−2) and 27,000 cycles at 20.0 mA cm^(−2)).Furthermore,a Zn/I_(2) full cell assembled by pairing with such an anode can maintain good stability for 3,500 cycles at 5.0 C,demonstrating the application potential of the as-prepared ZnIn anode for high-performance aqueous ZMBs.
基金funded by the German Federal Ministry of Education and Research(BMBF),project NextGen-3DBat,Grant Number 03XP0198Fby the Fraunhofer Cluster of Excellence Advanced Photon Sources(CAPS)。
文摘Direct Laser Interference Patterning(DLIP)is used to texture current collector foils in a roll-to-roll process using a high-power picosecond pulsed laser system operating at either fundamental wavelength of 1064 nm or 2nd harmonic of 532 nm.The raw beam having a diameter of 3 mm@1/e^(2) is shaped into an elongated top-hat intensity profile using a diffractive so-called FBS■-L element and cylindrical telescopes.The shaped beam is split into its diffraction orders,where the two first orders are parallelized and guided into a galvanometer scanner.The deflected beams inside the scan head are recombined with an F-theta objective on the working position generating the interference pattern.The DLIP spot has a line-like interference pattern with about 15μm spatial period.Laser fluences of up to 8 J cm^(-2) were achieved using a maximum pulse energy of 0.6 mJ.Furthermore,an in-house built roll-to-roll machine was developed.Using this setup,aluminum and copper foil of 20μm and 9μm thickness,respectively,could be processed.Subsequently to current collector structuring coating of composite electrode material took place.In case of lithium nickel manganese cobalt oxide(NMC 622)cathode deposited onto textured aluminum current collector,an increased specific discharge capacity could be achieved at a C-rate of 1℃.For the silicon/graphite anode material deposited onto textured copper current collector,an improved rate capability at all C-rates between C/10 and 5℃ was achieved.The rate capability was increased up to 100%compared to reference material.At C-rates between C/2 and 2℃,the specific discharge capacity was increased to 200 mAh g^(-1),while the reference electrodes with untextured current collector foils provided a specific discharge capacity of 100 m Ah g^(-1),showing the potential of the DLIP technology for cost-effective production of battery cells with increased cycle lifetime.
基金This work was financially supported by the National Key Research and Development Program of China(No.2016YFC1100402)the National Natural Science Foundation of China(Nos.51973222 and 51573186)+1 种基金the Natural Science Foundation of Jilin Province of China(Nos.20180101178JC and 20190701030GH)Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry,CIAC,CAS(Nos.201826 and 201715).
文摘Cell behaviors are regulated by a dynamic and complex environment characterized by biophysical,mechanical and biochemical properties.However,most works regulate cell behaviors under static conditions or by external factors.To control cell adhesion and proliferation with a dynamic and mechanical environment,we pattern the surface on self-healing copolymer P(MMA/nBA).The copolymer P(MMA/nBA)with the composition of 48/52(MMA/nBA)recovers nearly 100%of its original tensile strains after 86 h of recovery from deformation.The physical patterns on P(MMA/nBA)film are obtained over large areas and the size of the hole and the width of connecting bar are in line with the copper grid specifications.The patterned surface tends to be fiat after 12 h with almost 75%-80%recovery.Compared with cell incubation on polystyrene fiat and patterned surface of P(MMA/nBA)film without self-healing capability,the number and morphology of cells are well manipulated on the patterned surface of self-healing P(MMA/nBA)film.This approach provides a convenient method for dynamically regulating the cell behaviors on the surface of self-healing materials without chemical or biological modifications.
基金Project supported by the National Natural Science Foundation of China(No.52075484)the Zhejiang Provincial Funds for Distinguished Young Scientists of China(No.LR19E050001)the Fund for Creative Research Groups of National Natural Science Foundation of China(No.51821093)。
文摘Polymer-based materials with patterned functional particles have been used to develop smart devices with multiple functionalities.This paper presents a novel method to pattern microscale particles into biocompatible polyethylene glycol diacrylate(PEGDA)fluid through a designed surface acoustic wave(SAW)device with slanted-finger interdigital transducers(SFITs).By applying signals of different frequencies,the SFITs can excite SAWs with various wavelengths to pattern the microscale particles.The structural design and working principle of the SAW device with SFITs are firstly presented.To investigate the generation of standing SAWs and pressure field distributions of the SAW device with SFITs,a numerical model was developed.Simulation results showed that different strip-shape patterned pressure fields can be generated,and the period and width of adjacent strips can be adjusted by changing the frequencies of the excitation signals.Experiments were performed to verify that the microscale particles in the PEGDA solution can be successfully patterned into strip-shape patterns with various positions,periods,and widths.The results obtained in this study demonstrate that the developed method of using an SAW device with SFITs can be used for tunable patterning of microscale particles in solutions,and shows great potential for biomedical and microfluidic applications.
基金supported by National Natural Science Foundation of China(No.21573276)Natural Science Foundation of Jiangsu Province(No.BK20170007)Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2022ZB846).
文摘Utilizing superwettability micro/nanostructures to enhance the condensation heat transfer(CHT)performance of engineering materials has attracted great interest due to its values in basic research and technological innovations.Currently,exploring facile micro/nanofabrication approaches to create high-efficiency CHT surfaces has been one of research hotspots.In this work,we propose and demonstrate a type of new superwettability hybrid surface for high-efficiency CHT,which consists of superhydrophobic nanoneedle arrays and triangularly-patterned superhydrophilic microdots(SMDs).Such hybrid surface can be fabricated by the facile growth of densely-packed ZnO nanoneedles on the Zn-electroplated copper surface followed by fluorosilane modification and mask-assisted photodegradation.Through regulating the diameters and interspaces of SMDs,we obtain the optimized triangularly-patterned hybrid surface,which shows 42.7%higher CHT coefficient than the squarely-patterned hybrid surface and 58.5%higher CHT coefficient than the superhydrophobic surface.The key of such hybrid surface design is to considerably increase CHT coefficient brought about by SMD-triggered drop sweeping at the cost of slightly reducing heat transfer area of superhydrophobic functional zone for drop jumping.Such new strategy helps develop advanced CHT surfaces for high-efficiency electronic cooling and energy utilization.
基金supported by the Science and Technology Development Fund(FDCT),Macao SAR(No.0149/2022/A),and(No.0046/2024/AFJ)Guangdong Science and Technology Department(No.2023QN10C305)。
文摘A high humidity-resistant,dual mechanical responsive,and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane(PDMS)substrate with a thin film consisting of 90 wt%poly(vinyl butyral)(PVB)and 10 wt%hydroxypropyl cellulose(HPC)has been reported.The wrinkling system exhibited significant optical tuning from transparent to opaque states with 50%changes in transmittance,which was achieved through the dual mechanical modes of pre-stretching and releasing processes or bending.Upon exposure to ethanol vapor or a re-flattening process,wrinkles can be erased,yielding a transparent state.Consequently,the wrinkling system could be reversibly switched between transparency and opacity for 1000 cycles with marginal changes in the optical performance.Owing to the insolubility of PVB in water,the wrinkling patterns exhibited excellent durability in high-humidity environments(relative humidity(RH)=99%).Furthermore,the smart encryption device is also demonstrated via mechano-controlled surface topography by patterning the wrinkling system,suggesting potential applications of the designed structure in smart windows,anti-counterfeiting,dynamic display,optical information encryption,and rewritable surfaces.
基金support by Beijing Natural Science Foundation(3194046)BUCEA Post Graduate Innovation Project.
文摘The present work deals with the numerical study of the two-phase flow pattern and heat transfer characteristics of single-loop pulsating heat pipes(PHPs)under three modified surfaces(superhydrophilic evaporation section paired with superhydrophilic,superhydrophobic,and hybrid condensation section).The Volume of Fluid(VOF)model was utilized to capture the phase-change process within the PHPs.The study also evaluated the influence of surface wettability on fluid patterns and thermo-dynamic heat transfer performance under various heat fluxes.The results indicated that the effective nucleation and detachment of droplets are critical factors influencing the thermal performance of the PHPs.The overall heat transfer performance of the superhydrophobic surface was significantly improved at low heat flux.Under medium to high heat flux,the superhydrophilic condensation section exhibits a strong oscillation effect and leads to the thickening of the liquid film.In addition,the hybrid surface possesses the heat transfer characteristics of both superhydrophilic and superhydrophobic walls.The hybrid condensation section exhibited the lowest thermal resistance by 0.45 K/W at the heat flux of 10731 W/m^(2).The thermal resistance is reduced by 13.1%and 5.4%,respectively,compared to the superhydrophobic and superhydrophilic conditions.The proposed surface-modification method for achieving highly efficient condensation heat transfer is helpful for the design and operation of device-cooling components.
基金supported by the National Natural Science Foundation of China(No.52522405)Henan Provincial Natural Science Foundation(No.252300421323).
文摘Fractures in rock strata serve as flow pathways for gas flow.The undulation of fracture channels can influence the guidance of gas flow.In this context,four-point bending experiments on prefabricated fractured rocks at different angles under stable stepped loading stress.The experiment results clarified the evolutionary law that the undulation degree of the rock tensile fracture surface is separated by an initial fracture angle of 45°.The high undulation intervals were less than 45°,whereas the low undulation intervals were more than 45°.Furthermore,the relative undulation degree,undulation frequency,and matching degree of the fracture surface were quantified.The relationship between the change in fracture surface undulation and gas flow guidance was established.Based on this,the stability,tortuosity,and uniformity of the gas flow in the fracture channel were quantitatively characterized.Subsequently,numerical models of the fracture channels were constructed to validate the indices proposed in this study.The results of the study clarified the influence of different initial fracture angles on the undulation changes of fracture surfaces,and established the relationship between these changes and gas flow,which is conducive to understanding the role of internal fracture channels in rocks in guiding the gas flow process.
基金Tianjin Research Program of Application Foundation and Advanced Technology(No.14JCYBJC18600,No.14JCZDJC39700)National Key Scientific Instrument and Equipment Development Project(No.2013YQ17053903)
文摘Defect inspection of specular curved surface is a challenging job. Taking steel balls for example, a new method based on reflected pattern integrity recognition is put forward. The specular steel ball surface will totally reflect the patterns when it is placed inside a dome-shaped light source, whose inner wall is modified by patterns with certain regular. Distortion or intermittence of reflected pattern will occur at the defective part, which indicates the pattern has lost its integrity. Based on the integrity analysis of reflected pattern images？ surface defects can be revealed. In this paper, a set of concentric circles are used as the pattern and an image processing algorithm is customized to extract the surface defects. Results show that the proposed method is effective for the specular curved surface defect inspection
基金supported by the National Natural Science Foundation of China(grant 40573001)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20050284043 and No.20050284044).
文摘In order to investigate the effect of Thiobacillusferrooxidans on the oxidation of pyrite, two parallel experiments, which employed H2SO4 solutions and acidic solutions inoculated with ThiobaciUus ferrooxidans, were designed and carried out at 30℃. The initial pH of the two solutions was adjusted to 2.5 by dropwise addition of concentrated sulphuric acid. The surfaces of pyrite before exposure to leaching solutions and after exposure to the H2SO4 solutions and acidic solutions inoculated with Thiobacillus ferrooxidans were observed by scanning electron microscopy （SEM）. There were a variety of erosion patterns by Thiobacillusferrooxidans on the bio-leached pyrite surfaces. A conclusion can be drawn that the oxidation of pyrite might have been caused by erosion of the surfaces. Attachment of the bacteria to pyrite surfaces resulted in erosion pits, leading to the oxidation of pyrite. It is possible that the direct mechanism plays the most important role in the oxidation of pyrite. The changes in iron ion concentrations of both the experimental solutions with time suggest that ThiobaciUus ferrooxidans can enhance greatly the oxidation of pyrite.
基金jointly supported by the National Natural Science Foundation of China (Grant No. 41305069)the Open Project Program of the Key Laboratory of Meteorological Disaster of Ministry of Education,Nanjing University of Information Science and Technologythe National Program on Key Basic Research Project of China (Grant No. 2010CB951904)
文摘The spatial patterns and regional-scale surface air temperature （SAT） changes during the last millennium,as well as the variability of the East Asian summer monsoon （EASM） were simulated with a low-resolution version of Flexible Global Ocean-Atmosphere-Land-Sea-ice （FGOALS-gl） model.The model was driven by both natural and anthropogenic forcing agents.Major features of the simulated past millennial Northern Hemisphere （NH） mean SAT variations,including the Medieval Climate Anomaly （MCA）,the Little Ice Age （LIA） and the 20th Century Warming （20CW）,were generally consistent with the reconstructions.The simulated MCA showed a global cooling pattern with reference to the 1961-90 mean conditions,indicating the 20CW to be unprecedented over the last millennium in the simulation.The LIA was characterized by pronounced coldness over the continental extratropical NH in both the reconstruction and the simulation.The simulated global mean SAT difference between the MCA and LIA was 0.14°C,with enhanced warming over high-latitude NH continental regions.Consistencies between the simulation and the reconstruction on regional scales were lower than those on hemispheric scales.The major features agreed well between the simulated and reconstructed SAT variations over the Chinese domain,despite some inconsistency in details among different reconstructions.The EASM circulation during the MCA was stronger than that during the LIA The corresponding rainfall anomalies exhibited excessive rainfall in the north but deficient rainfall in the south.Both the zonal and meridional thermal contrast were enhanced during the MCA.This temperature anomaly pattern favored a stronger monsoon circulation.
基金supported by the National Basic Research Program (973) of China (No. 2008CB418104)the Major Programs of the Chinese Academy of Sciences (No. KZCX1-YW-14-4-1)the National Natural Science Foundation of China (No. 40901265)
文摘Impervious surfaces are the result of urbanization that can be explicitly quantified, managed and controlled at each stage of land development. It is a very useful environmental indicator that can be used to measure the impacts of urbanization on surface runoff, water quality, air quality, biodiversity and rnicroclimate. Therefore, accurate estimation of impervious surfaces is critical for urban environmental monitoring, land management, decision-making and urban planning. Many approaches have been developed to estimate surface imperviousness, using remotely sensed data with various spatial resolutions. However, few studies, have investigated the effects of spatial resolution on estimating surface imperviousness. We compare medium-resolution Landsat data with high-resolution SPOT images to quantify the imperviousness in Beijing, China. The results indicated that the overall 91% accuracy of estimates of imperviousness based on TM data was considerably higher than the 81% accuracy of the SPOT data. The higher resolution SPOT data did not always predict the imperviousness of the land better than the TM data. At the whole city level, the TM data better predicts the percentage cover of impervious surfaces. At the sub-city level, however, the ring belts from the central core to the urban-rural peripheral, the SPOT data may better predict the imperviousness. These results highlighted the need to combine multiple resolution data to quantify the percentage of imperviousness, as higher resolution data do not necessarily lead to more accurate estimates. The methodology and results in this study can be utilized to identify the most suitable remote sensing data to quickly and efficiently extract the pattern of the impervious land, which could provide the base for further study on many related urban environmental problems.
基金National Natural Science Foundation of China (No.49831070) ShanghaiMunicipal Education Commission.
文摘On the basis of field investigations, observations andexperimental data combined with environmental monitoring information,the status and the spatial and temporal patterns of surface waterpollution over the past ten years in the Yangtze River Delta havebeen assessed. The water quality of large rivers is still very goodbut most of the medium-sized and small rivers have been veryseriously polluted. The appearance of black and odorous conditions inrivers in the urban areas has increased due to serious pollution byorganic matter with consequent high oxygen demand. Annual increasesin N and P concentrations in lakes have accelerated eutrophication.The water quality of river sin small towns is rapidly deteriorating.The main sources of surface water pollution include industrial anddomestic sewage, animal manures, chemical fertilizers in farmland,and polluted sediments in rivers and lakes.
