Gelatinase A (MMP-2) is considered to play a critical role in cell migration and invasion. The proteinase is secreted from the cell as an inactive zymogen. In vivo it is postulated that activation of progelationase A ...Gelatinase A (MMP-2) is considered to play a critical role in cell migration and invasion. The proteinase is secreted from the cell as an inactive zymogen. In vivo it is postulated that activation of progelationase A (proMMP-2) takes place on the cell surface mediated by membrane-type matrix metalloproteinases (MT-MMPs). Recent studies have demonstrated that proMMP-2 is recruited to the cell surface by interacting with tissue inhibitor of metalloproteinases-2 (TIMP-2) bound to MT1MMP by forming a ternary complex. bee MT1-MMP closely located to the ternary complex then activates proMMP-2 on the cell surface. MT1-MMP is found in cultured invasive cancer cells at the invadopodia. The MTMMP/TIMP-2/ MMP- 2 system t bus provides localized expression of proteolysis of the extracellular matrix required for cell migration.展开更多
Boron is a very promising and highly attractive fuel because of high calorific value. However, the practical applications in explosives and propellants of boron have been limited by long ignition delay time and low co...Boron is a very promising and highly attractive fuel because of high calorific value. However, the practical applications in explosives and propellants of boron have been limited by long ignition delay time and low combustion efficiency. Herein, nano-Al and graphene fluoride(GF) as surface activated materials are employed to coat boron(B) particles to improve ignition and combustion performance. The reaction heat of nano-Al coated B/KNO_(3)and GF coated B/KNO_(3)are 1116.83 J/g and 862.69 J/g, respectively, which are higher than that of pure B/KNO_(3)(823.39 J/g). The ignition delay time of B/KNO_(3)could be reduced through nano-Al coating. The shortest ignition delay time is only 75 ms for B coated with nano-Al of 8 wt%, which is much shorter than that of pure B/KNO_(3)(109 ms). However, the ignition delay time of B/KNOcoated with GF has been increased from 109 to 187 ms. B coated with GF and nano-Al shown significantly influence on the pressure output and flame structure of B/KNO_(3). Furthermore, the effects of B/O ratios on the pressure output and ignition delay time have been further fully studied. For B/KNO_(3)coated with nano-Al and GF, the highest pressures are 88 KPa and 59 KPa for B/O ratio of 4:6, and the minimum ignition delay time are 94 ms and 148 ms for B/O ratio of 7:3. Based on the above results, the reaction process of boron coated with GF and nano-Al has been proposed to understand combustion mechanism.展开更多
In this work, surface activation of automotive polymers using atmospheric pressure plasmas was investigated. The aim was to increase the polar fraction of the surface energy of both plane and convex polymer devices wi...In this work, surface activation of automotive polymers using atmospheric pressure plasmas was investigated. The aim was to increase the polar fraction of the surface energy of both plane and convex polymer devices with a radius in the range of 30 mm. For this purpose, a fittable low temperature atmospheric pressure plasma source based on capacitively coupled multi-pin electrodes was set up and applied. Each single electrode generates a treatment spot of approximately 2 cm2 with a tunable power density of up to 1.4 W/cm2. The surface energy was evaluated by contact angle measurements. After treatment at a low energy density of 1.01 J/cm2, the polar fraction of the surface energy of the investigated polymers was increased by a factor of 3.3 to 132, depending on the polymer materials. It was shown that by applying the presented fittable plasma source, this effect is independent of the surface radius of the polymer sample.展开更多
ZrCo alloy holds great promise for hydrogen isotope storage,yet its susceptibility to poisoning by impurity gases,especially CO,poses a challenge.This susceptibility arises due to the electron acceptor nature of the s...ZrCo alloy holds great promise for hydrogen isotope storage,yet its susceptibility to poisoning by impurity gases,especially CO,poses a challenge.This susceptibility arises due to the electron acceptor nature of the surface Co element and the formation of the d-πfeedback bond,thereby impeding the surface hydrogen dissociation.Accordingly,we propose a novel local activity modulation strategy,where substituent elements are sacrificed to protect the active Co sites for hydrogen dissociation.Considering CO absorption capacity,solid solubility,and hydrogen affinity,we selected V,Cr,and Mn as microalloying elements and successfully prepared the single-phase ZrCo_(0.97)(VCrMn)_(0.03)alloy.Compared to pristine ZrCo,ZrCo_(0.97)(VCrMn)_(0.03)demonstrates significantly enhanced poisoning resistance.Notably,the hydrogenation kinetics of ZrCo_(0.97)(VCrMn)_(0.03)is 2.4 times higher than that of ZrCo in 4 bar H_(2)+5000 ppm CO.Interestingly,the controllable in situ formation of the Co_(2)C phase shell structure during cycling further safeguards the surface reactivity of ZrCo_(0.97)(VCrMn)_(0.03).Consequently,its capacity retention ratio after 25 cycles has been improved to 74.5%from 55.3%of the ZrCo alloy.These findings suggest that micro-alloying engineering could be a promising strategy for surface activity modulation to enhance the anti-poisoning properties of hydrogen storage materials.展开更多
In this paper,we examine an illegal wireless communication network consisting of an illegal user receiving illegal signals from an illegal station and propose an active reconfigurable intelligent surface(ARIS)-assiste...In this paper,we examine an illegal wireless communication network consisting of an illegal user receiving illegal signals from an illegal station and propose an active reconfigurable intelligent surface(ARIS)-assisted multi-antenna jamming(MAJ)scheme denoted by ARIS-MAJ to interfere with the illegal signal transmission.In order to strike a balance between the jamming performance and the energy consumption,we consider a so-called jamming energy efficiency(JEE)which is defined as the ratio of achievable rate reduced by the jamming system to the corresponding power consumption.We formulate an optimization problem to maximize the JEE for the proposed ARIS-MAJ scheme by jointly optimizing the jammer’s beamforming vector and ARIS’s reflecting coefficients under the constraint that the jamming power received at the illegal user is lower than the illegal user’s detection threshold.To address the non-convex optimization problem,we propose the Dinkelbach-based alternating optimization(AO)algorithm by applying the semidefinite relaxation(SDR)algorithm with Gaussian randomization method.Numerical results validate that the proposed ARIS-MAJ scheme outperforms the passive reconfigurable intelligent surface(PRIS)-assisted multi-antenna jamming(PRIS-MAJ)scheme and the conventional multiantenna jamming scheme without RIS(NRIS-MAJ)in terms of the JEE.展开更多
Formaldehyde(HCHO) and carbon monoxide(CO) are both common air pollutants and hazardous to human body. It is imperative to develop the catalyst that is able to efficiently remove these pollutants. In this work, we act...Formaldehyde(HCHO) and carbon monoxide(CO) are both common air pollutants and hazardous to human body. It is imperative to develop the catalyst that is able to efficiently remove these pollutants. In this work, we activated Pt-MnO_(2)under different conditions for highly active oxidation of HCHO and CO, and the catalyst activated under CO displayed superior performance. A suite of complementary characterizations revealed that the catalyst activated with CO created the highly dispersed Pt nanoparticles to maintain a more positively charged state of Pt, which appropriately weakens the Mn-O bonding strength in the adjacent region of Pt for efficient supply of active oxygen during the reaction. Compared with other catalysts activated under different conditions, the CO-activated Pt-MnO_(2)displays much higher activity for oxidation of HCHO and CO. This research contributes to elucidating the mechanism for regulating the oxidation activity of Pt-based catalyst.展开更多
Ab initio potential surface of oxidative addition of CH4 to coordinatively unsaturated PtC12 is presented. The electron correlation has a big effect on the transition state and activation energy.
Complex organics contained in dye wastewater are difficult to degrade and often require electrochemical advanced oxidation processes（EAOPs） to treat it. Surface activation of the electrode used in such treatment is ...Complex organics contained in dye wastewater are difficult to degrade and often require electrochemical advanced oxidation processes（EAOPs） to treat it. Surface activation of the electrode used in such treatment is an important factor determining the success of the process.The performance of boron-doped nanocrystalline diamond（BD-NCD） film electrode for decolorization of Acid Yellow（AY-36） azo dye with respect to the surface activation by electrochemical polarization was studied. Anodic polarization found to be more suitable as electrode pretreatment compared to cathodic one. After anodic polarization, the originally H-terminated surface of BD-NCD was changed into O-terminated, making it more hydrophilic.Due to the oxidation of surface functional groups and some portion of sp2 carbon in the BD-NCD film during anodic polarization, the electrode was successfully being activated showing lower background current, wider potential window and considerably less surface activity compared to the non-polarized one. Consequently, electrooxidation（EO） capability of the anodically-polarized BD-NCD to degrade AY-36 dye was significantly enhanced, capable of nearly total decolorization and chemical oxygen demand（COD） removal even after several times of re-using. The BD-NCD film electrode favored acidic condition for the dye degradation; and the presence of chloride ion in the solution was found to be more advantageous than sulfate active species.展开更多
In this paper,the effect of sodium laurate(SL)on the properties of sodium lauroyl glutamate(SLG),such as surface activity,foam,wetting,emulsification,and resistance to hard water,has been systematically investigated.T...In this paper,the effect of sodium laurate(SL)on the properties of sodium lauroyl glutamate(SLG),such as surface activity,foam,wetting,emulsification,and resistance to hard water,has been systematically investigated.The results showed that the critical micelle concentration(cmc)of SLG was 0.30 mmol/L,and the surface tension at the cmc(γcmc)was 34.95 mN/m.With the increase of SL content,the efficiency of SLG solution in reducing the surface tension was decreased.When the SL content was increased,there was no significant change in the foaming ability and foam stability of SLG solutions.The increase of SL content improved both the emulsification and wettability of SLG,but reduced its water resistance.展开更多
Mesoporous carbon supports mitigate platinum(Pt)sulfonic poisoning through nanopore-confined Pt deposition,yet their morphological impacts on oxygen transport remain unclear.This study integrates carbon support morpho...Mesoporous carbon supports mitigate platinum(Pt)sulfonic poisoning through nanopore-confined Pt deposition,yet their morphological impacts on oxygen transport remain unclear.This study integrates carbon support morphology simulation with an enhanced agglomerate model to establish a mathematical framework elucidating pore evolution,Pt utilization,and oxygen transport in catalyst layers.Results demonstrate dominant local mass transport resistance governed by three factors:(1)active site density dictating oxygen flux;(2)ionomer film thickness defining shortest transport path;(3)ionomer-to-Pt surface area ratio modulating practical pathway length.At low ionomer-to-carbon(I/C)ratios,limited active sites elevate resistance(Factor 1 dominant).Higher I/C ratios improve the ionomer coverage but eventually thicken ionomer films,degrading transport(Factors 2–3 dominant).The results indicate that larger carbon particles result in a net increase in local transport resistance by reducing external surface area and increasing ionomer thickness.As the proportion of Pt situated in nanopores or the Pt mass fraction increases,elevated Pt density inside the nanopores exacerbates pore blockage.This leads to the increased transport resistance by reducing active sites,and increasing ionomer thickness and surface area.Lower Pt loading linearly intensifies oxygen flux resistance.The model underscores the necessity to optimize support morphology,Pt distribution,and ionomer content to prevent pore blockage while balancing catalytic activity and transport efficiency.These insights provide a systematic approach for designing high-performance mesoporous carbon catalysts.展开更多
This article presents the construction of scaffolds composed of polylactic acid(PLA)with different concentrations of hydroxyapatite(HA)by electrospinning,which were superficially modified with polypyrrole(PPy/I)by pla...This article presents the construction of scaffolds composed of polylactic acid(PLA)with different concentrations of hydroxyapatite(HA)by electrospinning,which were superficially modified with polypyrrole(PPy/I)by plasma polymerization.A preliminary study was conducted of the biological and mechanical behavior of the scaffolds when they were implanted in the back of rabbits for 30 days;bone cells differentiated from mesenchymal stem cells(MSCs)were used.The bone cell and scaffold structures were characterized by histological,immunohistochemical,and mechanical stress tests.Hematoxylin–eosin staining showed good tissue conformation.The immunohistochemical tests highlighted the presence of the main bone tissue proteins,such as collagen,osteocalcin,and osteopontin.The PLA/HA scaffolds were observed to exhibit cell adhesion and proliferation properties;however,the response was much better in the scaffolds that had a higher concentration of HA and that were coated with PPy/I.The results of the mechanical tests of the scaffolds indicated that the plasma treatment improved the adhesion and cell proliferation properties and contributed to the mechanical support,allowing the formation of neotissues with good viability of cell growth.展开更多
From April 21st to 23rd,the 2025 China Surfactant Industry Conference was successfully held in Hangzhou.The conference was hosted by China Research Institute of Daily Chemical,and the National Engineering Research Cen...From April 21st to 23rd,the 2025 China Surfactant Industry Conference was successfully held in Hangzhou.The conference was hosted by China Research Institute of Daily Chemical,and the National Engineering Research Center for Surfactant,undertaken by the National Productivity Promotion Center for Surfactant and Detergent Industry and the China Daily Chemical Industry Information Center,specially co-organized by Zanyu Technology Group Co.,Ltd,and jointly co-organized by the China Surface Active Agent Industry Alliance (SAA),the Malaysian Palm Oil Board (MPOB),the Roundtable on Sustainable Palm Oil (RSPO),and the American Oil Chemists’ Society (AOCS).展开更多
Isomorphic substitution of ferric ion(Fe~(3+))by aluminum ion(Al~(3+))in iron(hydro)oxides is ubiquitous in natural environments.Aluminum substitution inevitably leads to changes in the microstructures,physicochemical...Isomorphic substitution of ferric ion(Fe~(3+))by aluminum ion(Al~(3+))in iron(hydro)oxides is ubiquitous in natural environments.Aluminum substitution inevitably leads to changes in the microstructures,physicochemical properties,and surface reactions of iron(hydro)oxides,which may have great impacts on the sequestration of nutrients and contaminants in soils and aquatic environments.Over the past decades,the structural properties and surface reactivity of Al-substituted iron(hydro)oxides have been intensively studied.Iron(hydro)oxides in various structural forms and with different Al substitution amounts present high application potentials in addressing environmental issues.A timely summary of the structural properties and interfacial reactions of the most common and representative Al-substituted iron(hydro)oxides is of significance.Herein,the effects of Al substitution on the structural properties and surface activities of iron(hydro)oxides were clarified according to the microstructure,crystal facets,surface site type and density,interfacial reaction mechanisms,and modeling parameters of iron(hydro)oxides.This review systematically elucidates how Al substitution affects the structural properties and surface reactions of iron(hydro)oxides,including the well crystallized goethite and hematite and the poorly crystallized ferrihydrite,providing theoretical guidance for further exploration of the mineralogical characteristics and environmental geochemical behaviors of iron(hydro)oxides.展开更多
This paper considers a multi-antenna ac-cess point(AP)transmitting secrecy message to a single-antenna user in the presence of a single-antenna illegal eavesdropper(Eve)and proposes a double ac-tive reconfigurable int...This paper considers a multi-antenna ac-cess point(AP)transmitting secrecy message to a single-antenna user in the presence of a single-antenna illegal eavesdropper(Eve)and proposes a double ac-tive reconfigurable intelligent surfaces(DARISs)as-sisted physical layer security(PLS)scheme denoted by DARISs-PLS to protect the secrecy message trans-mission.We formulate a secrecy rate maximization problem for the proposed DARISs-PLS scheme by considering a power budget constraint for the two ac-tive reconfigurable intelligent surfaces(ARISs)and AP.To address the formulated optimization problem,we jointly optimize the reflecting coefficients for the two ARISs and the beamforming at the AP in an it-erative manner by applying Dinkelbach based alter-nating optimization(AO)algorithm and a customized iterative algorithm together with the semidefinite re-laxation(SDR).Numerical results reveal that the pro-posed DARISs-PLS scheme outperforms the dou-ble passive reconfigurable intelligent surfaces-assisted PLS method(DPRISs-PLS)and single ARIS-assisted PLS method(SARIS-PLS)in terms of the secrecy rate.展开更多
YAG laser welding with surface activating flux has been investigated, and the influencing factors and mechanism are discussed. The results show that both surface activating flux and surface active element S have fanta...YAG laser welding with surface activating flux has been investigated, and the influencing factors and mechanism are discussed. The results show that both surface activating flux and surface active element S have fantastic effects on the YAG laser weld shape, that is to obviously increase the weld penetration and D/W ratio in various welding conditions. The mechanism is thought to be the change of weld pool surface tension temperature coefficient, thus, the change of fluid flow pattern in weld pool due to the flux.展开更多
α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decrease...α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decreased in the order:γ‐MnO2>α‐MnO2>δ‐MnO2>β‐MnO2.The NOx conversion with the use ofγ‐MnO2andα‐MnO2catalysts reached90%in the temperature range of140–200°C,while that based onβ‐MnO2reached only40%at200°C.Theγ‐MnO2andα‐MnO2nanowire crystal morphologies enabled good dispersion of the catalysts and resulted in a relatively high specific surface area.We found thatγ‐MnO2andα‐MnO2possessed stronger reducing abilities and more and stronger acidic sites than the other catalysts.In addition,more chemisorbed oxygen existed on the surface of theγ‐MnO2andα‐MnO2catalysts.Theγ‐MnO2andα‐MnO2catalysts showed excellent performance in the low‐temperature SCR of NO to N2with NH3.展开更多
A novel C/Pb composite has been successfully prepared by electmless plating to reduce the hydrogenevolution and achieve the high reversibility of the anode of lead-carbon battery （LCB）. The depositedlead on the surf...A novel C/Pb composite has been successfully prepared by electmless plating to reduce the hydrogenevolution and achieve the high reversibility of the anode of lead-carbon battery （LCB）. The depositedlead on the surface of C/Pb composite was found to be uniform and adherent to carbon surface. Becauselead has been stuck on the surface of C/Pb composite, the embedded structure suppresses the hydrogenevolution of lead-carbon anode and strengthens the connection between carbon additive and sponge lead.Compared with the blank anode, the lead-carbon anode with C/Pb composite displays excellent charge-discharge reversibility, which is attributed to the good connection between carbon additives and leadthat has been stuck on the surface of C/Pb composite during the preparation process. The addition of CIPb composite maintains a solid anode structure with high specific surface area and power volume, andthereby, it plays a significant role in the highly reversible lead-carbon anode.展开更多
A series of activated carbons from Taixi anthracite were prepared by steam activation in the presence of KOH and then they were modified by different methods. The regulation of porosity and the modification of surface...A series of activated carbons from Taixi anthracite were prepared by steam activation in the presence of KOH and then they were modified by different methods. The regulation of porosity and the modification of surface chemistry were carried out with the aim to improve the benzene adsorption capacity of activated carbon. The influences of KOH and activation process parameters including activation temperature, activation time and steam flow rate on porosity of activated carbon were evaluated, and the effect of modification methods on surface chemistry was investigated. Also, the relationship between benzene adsorption capacity and porosity and surface chemistry was analyzed. Results show that activation temperature is the dominant factor in the activation process; the introduction of KOH into the raw material can enhance the reactivity of char in activation process, meanwhile it shows a negative effect on the porosity development, especially on the mesopore development. Results of FTIR analysis indicate that anthracite-based activated carbon with condensed aromatics and chemically inert oxygen does not present the nature to be surface modified. Besides, benzene adsorption capacity has an approximate linear relationship with surface area and in our preparation, benzene adsorption capacity and surface area of activated carbon are up to 1210 m 2 /g and 423 mg/g, respectively.展开更多
Five new zwitterionic surfactants with long chain alkyl betaine structure incorporated with hydroxylpropyl group have been synthesized. Their structures were identified by elemental analysis, IR (HNMR)-H-1, and (CNMR)...Five new zwitterionic surfactants with long chain alkyl betaine structure incorporated with hydroxylpropyl group have been synthesized. Their structures were identified by elemental analysis, IR (HNMR)-H-1, and (CNMR)-C-13. Surface tension experiments showed that these surfactants have higher surface activity than those without hydroxypropyl group. The values of CMC and gamma(CMC) of these surfactants have been determined.展开更多
Fluorosurfactants are the key ingredients in the formulations of aqueous film-forming foams(AFFFs)for extinguishing flammable liquids,thus developing high-efficient and low-toxic fluorosurfactants is desirable in AFFF...Fluorosurfactants are the key ingredients in the formulations of aqueous film-forming foams(AFFFs)for extinguishing flammable liquids,thus developing high-efficient and low-toxic fluorosurfactants is desirable in AFFFs application.Herein,a series of hyperbranched polymeric fluorosu rfactants(HPFs)were successfully synthesized through sequentially modifying hyperbranched polyethylenimine(PEI)with the hydrophilic poly(ethylene glycol)(PEG)chains and the hydrophobic C6/C4-based perfluoroalkyl chains,which were verified by FTIR,^(1)H-and^(19)F-NMR.The surface tensions of all the HPFs in water were measured,and the corresponding physicochemical parameters were interpreted.It was found that the surface activities of HPFs could be tuned through adjusting the ratio of PEG to perfluoroalkyl chains,the length of perfluoroalkyl chains,the molecular weight of PEI core,but not the PEG chain length.In the binary mixture of HPFs with the commercial small molecule fluorosurfactant Capstone^(TM)1157(C1157),a strong synergism led to the elevation of surface activity,which was attributed to the efficient encapsulation of C1157 vips by the compact hyperbranched HPFs as the hosts.The utilization of HPF/C1157 as fluorosurfactant ingredients in AFFF formulations could realize much higher fire-extinguishing efficiency towards flammable oils than the control AFFFs prepa red from the polymeric Capstone^(TM)1460 or the neat C1157.展开更多
文摘Gelatinase A (MMP-2) is considered to play a critical role in cell migration and invasion. The proteinase is secreted from the cell as an inactive zymogen. In vivo it is postulated that activation of progelationase A (proMMP-2) takes place on the cell surface mediated by membrane-type matrix metalloproteinases (MT-MMPs). Recent studies have demonstrated that proMMP-2 is recruited to the cell surface by interacting with tissue inhibitor of metalloproteinases-2 (TIMP-2) bound to MT1MMP by forming a ternary complex. bee MT1-MMP closely located to the ternary complex then activates proMMP-2 on the cell surface. MT1-MMP is found in cultured invasive cancer cells at the invadopodia. The MTMMP/TIMP-2/ MMP- 2 system t bus provides localized expression of proteolysis of the extracellular matrix required for cell migration.
基金supported by the National Natural Science Foundation of China (11872341 and 22075261)。
文摘Boron is a very promising and highly attractive fuel because of high calorific value. However, the practical applications in explosives and propellants of boron have been limited by long ignition delay time and low combustion efficiency. Herein, nano-Al and graphene fluoride(GF) as surface activated materials are employed to coat boron(B) particles to improve ignition and combustion performance. The reaction heat of nano-Al coated B/KNO_(3)and GF coated B/KNO_(3)are 1116.83 J/g and 862.69 J/g, respectively, which are higher than that of pure B/KNO_(3)(823.39 J/g). The ignition delay time of B/KNO_(3)could be reduced through nano-Al coating. The shortest ignition delay time is only 75 ms for B coated with nano-Al of 8 wt%, which is much shorter than that of pure B/KNO_(3)(109 ms). However, the ignition delay time of B/KNOcoated with GF has been increased from 109 to 187 ms. B coated with GF and nano-Al shown significantly influence on the pressure output and flame structure of B/KNO_(3). Furthermore, the effects of B/O ratios on the pressure output and ignition delay time have been further fully studied. For B/KNO_(3)coated with nano-Al and GF, the highest pressures are 88 KPa and 59 KPa for B/O ratio of 4:6, and the minimum ignition delay time are 94 ms and 148 ms for B/O ratio of 7:3. Based on the above results, the reaction process of boron coated with GF and nano-Al has been proposed to understand combustion mechanism.
基金supported by the European Regional Development Funds(EFRE)and the Workgroup Innovative Projects of Lower Saxony(AGiP) in the Frame of the Lower Saxony Innovation Network for Plasma Technology(NIP),Project Funding Reference Number W2-80029388
文摘In this work, surface activation of automotive polymers using atmospheric pressure plasmas was investigated. The aim was to increase the polar fraction of the surface energy of both plane and convex polymer devices with a radius in the range of 30 mm. For this purpose, a fittable low temperature atmospheric pressure plasma source based on capacitively coupled multi-pin electrodes was set up and applied. Each single electrode generates a treatment spot of approximately 2 cm2 with a tunable power density of up to 1.4 W/cm2. The surface energy was evaluated by contact angle measurements. After treatment at a low energy density of 1.01 J/cm2, the polar fraction of the surface energy of the investigated polymers was increased by a factor of 3.3 to 132, depending on the polymer materials. It was shown that by applying the presented fittable plasma source, this effect is independent of the surface radius of the polymer sample.
基金financially supported by the National Key Research and Development Program of China(2022YFE03170002)the National Natural Science Foundation of China(52071286,U203020852171223)。
文摘ZrCo alloy holds great promise for hydrogen isotope storage,yet its susceptibility to poisoning by impurity gases,especially CO,poses a challenge.This susceptibility arises due to the electron acceptor nature of the surface Co element and the formation of the d-πfeedback bond,thereby impeding the surface hydrogen dissociation.Accordingly,we propose a novel local activity modulation strategy,where substituent elements are sacrificed to protect the active Co sites for hydrogen dissociation.Considering CO absorption capacity,solid solubility,and hydrogen affinity,we selected V,Cr,and Mn as microalloying elements and successfully prepared the single-phase ZrCo_(0.97)(VCrMn)_(0.03)alloy.Compared to pristine ZrCo,ZrCo_(0.97)(VCrMn)_(0.03)demonstrates significantly enhanced poisoning resistance.Notably,the hydrogenation kinetics of ZrCo_(0.97)(VCrMn)_(0.03)is 2.4 times higher than that of ZrCo in 4 bar H_(2)+5000 ppm CO.Interestingly,the controllable in situ formation of the Co_(2)C phase shell structure during cycling further safeguards the surface reactivity of ZrCo_(0.97)(VCrMn)_(0.03).Consequently,its capacity retention ratio after 25 cycles has been improved to 74.5%from 55.3%of the ZrCo alloy.These findings suggest that micro-alloying engineering could be a promising strategy for surface activity modulation to enhance the anti-poisoning properties of hydrogen storage materials.
基金supported in part by the National Natural Science Foundation of China under Grant 62071253,Grant 62371252 and Grant 62271268in part by the Jiangsu Provincial Key Research and Development Program under Grant BE2022800in part by the Jiangsu Provincial 333 Talent Project.
文摘In this paper,we examine an illegal wireless communication network consisting of an illegal user receiving illegal signals from an illegal station and propose an active reconfigurable intelligent surface(ARIS)-assisted multi-antenna jamming(MAJ)scheme denoted by ARIS-MAJ to interfere with the illegal signal transmission.In order to strike a balance between the jamming performance and the energy consumption,we consider a so-called jamming energy efficiency(JEE)which is defined as the ratio of achievable rate reduced by the jamming system to the corresponding power consumption.We formulate an optimization problem to maximize the JEE for the proposed ARIS-MAJ scheme by jointly optimizing the jammer’s beamforming vector and ARIS’s reflecting coefficients under the constraint that the jamming power received at the illegal user is lower than the illegal user’s detection threshold.To address the non-convex optimization problem,we propose the Dinkelbach-based alternating optimization(AO)algorithm by applying the semidefinite relaxation(SDR)algorithm with Gaussian randomization method.Numerical results validate that the proposed ARIS-MAJ scheme outperforms the passive reconfigurable intelligent surface(PRIS)-assisted multi-antenna jamming(PRIS-MAJ)scheme and the conventional multiantenna jamming scheme without RIS(NRIS-MAJ)in terms of the JEE.
基金supported by the National Natural Science Foundation of China (Nos. 22025604, 21976196, 21972170 and 22072184)。
文摘Formaldehyde(HCHO) and carbon monoxide(CO) are both common air pollutants and hazardous to human body. It is imperative to develop the catalyst that is able to efficiently remove these pollutants. In this work, we activated Pt-MnO_(2)under different conditions for highly active oxidation of HCHO and CO, and the catalyst activated under CO displayed superior performance. A suite of complementary characterizations revealed that the catalyst activated with CO created the highly dispersed Pt nanoparticles to maintain a more positively charged state of Pt, which appropriately weakens the Mn-O bonding strength in the adjacent region of Pt for efficient supply of active oxygen during the reaction. Compared with other catalysts activated under different conditions, the CO-activated Pt-MnO_(2)displays much higher activity for oxidation of HCHO and CO. This research contributes to elucidating the mechanism for regulating the oxidation activity of Pt-based catalyst.
文摘Ab initio potential surface of oxidative addition of CH4 to coordinatively unsaturated PtC12 is presented. The electron correlation has a big effect on the transition state and activation energy.
基金financially supported by "National" Science Council of Taiwan by Grant NSC 99-2221-E-009-042Ministry of Economic Affairs of Taiwan by Grant 101-EC-17-A-08-S1-208
文摘Complex organics contained in dye wastewater are difficult to degrade and often require electrochemical advanced oxidation processes（EAOPs） to treat it. Surface activation of the electrode used in such treatment is an important factor determining the success of the process.The performance of boron-doped nanocrystalline diamond（BD-NCD） film electrode for decolorization of Acid Yellow（AY-36） azo dye with respect to the surface activation by electrochemical polarization was studied. Anodic polarization found to be more suitable as electrode pretreatment compared to cathodic one. After anodic polarization, the originally H-terminated surface of BD-NCD was changed into O-terminated, making it more hydrophilic.Due to the oxidation of surface functional groups and some portion of sp2 carbon in the BD-NCD film during anodic polarization, the electrode was successfully being activated showing lower background current, wider potential window and considerably less surface activity compared to the non-polarized one. Consequently, electrooxidation（EO） capability of the anodically-polarized BD-NCD to degrade AY-36 dye was significantly enhanced, capable of nearly total decolorization and chemical oxygen demand（COD） removal even after several times of re-using. The BD-NCD film electrode favored acidic condition for the dye degradation; and the presence of chloride ion in the solution was found to be more advantageous than sulfate active species.
文摘In this paper,the effect of sodium laurate(SL)on the properties of sodium lauroyl glutamate(SLG),such as surface activity,foam,wetting,emulsification,and resistance to hard water,has been systematically investigated.The results showed that the critical micelle concentration(cmc)of SLG was 0.30 mmol/L,and the surface tension at the cmc(γcmc)was 34.95 mN/m.With the increase of SL content,the efficiency of SLG solution in reducing the surface tension was decreased.When the SL content was increased,there was no significant change in the foaming ability and foam stability of SLG solutions.The increase of SL content improved both the emulsification and wettability of SLG,but reduced its water resistance.
基金supported by the Program of Ministry of Science and Technology of China(No.2023YFB2504200)support of Shanghai Rising-Star Program(Grant No.24QB2703200)the Major Science and Technology Projects of Yunnan Province(No.202302AH360001).
文摘Mesoporous carbon supports mitigate platinum(Pt)sulfonic poisoning through nanopore-confined Pt deposition,yet their morphological impacts on oxygen transport remain unclear.This study integrates carbon support morphology simulation with an enhanced agglomerate model to establish a mathematical framework elucidating pore evolution,Pt utilization,and oxygen transport in catalyst layers.Results demonstrate dominant local mass transport resistance governed by three factors:(1)active site density dictating oxygen flux;(2)ionomer film thickness defining shortest transport path;(3)ionomer-to-Pt surface area ratio modulating practical pathway length.At low ionomer-to-carbon(I/C)ratios,limited active sites elevate resistance(Factor 1 dominant).Higher I/C ratios improve the ionomer coverage but eventually thicken ionomer films,degrading transport(Factors 2–3 dominant).The results indicate that larger carbon particles result in a net increase in local transport resistance by reducing external surface area and increasing ionomer thickness.As the proportion of Pt situated in nanopores or the Pt mass fraction increases,elevated Pt density inside the nanopores exacerbates pore blockage.This leads to the increased transport resistance by reducing active sites,and increasing ionomer thickness and surface area.Lower Pt loading linearly intensifies oxygen flux resistance.The model underscores the necessity to optimize support morphology,Pt distribution,and ionomer content to prevent pore blockage while balancing catalytic activity and transport efficiency.These insights provide a systematic approach for designing high-performance mesoporous carbon catalysts.
基金supported by Universidad La Salle México and the Faculty of Engineering,Grant No.EC388-IMC-13/18CONACYT,Grant No.CB16RF_287927.
文摘This article presents the construction of scaffolds composed of polylactic acid(PLA)with different concentrations of hydroxyapatite(HA)by electrospinning,which were superficially modified with polypyrrole(PPy/I)by plasma polymerization.A preliminary study was conducted of the biological and mechanical behavior of the scaffolds when they were implanted in the back of rabbits for 30 days;bone cells differentiated from mesenchymal stem cells(MSCs)were used.The bone cell and scaffold structures were characterized by histological,immunohistochemical,and mechanical stress tests.Hematoxylin–eosin staining showed good tissue conformation.The immunohistochemical tests highlighted the presence of the main bone tissue proteins,such as collagen,osteocalcin,and osteopontin.The PLA/HA scaffolds were observed to exhibit cell adhesion and proliferation properties;however,the response was much better in the scaffolds that had a higher concentration of HA and that were coated with PPy/I.The results of the mechanical tests of the scaffolds indicated that the plasma treatment improved the adhesion and cell proliferation properties and contributed to the mechanical support,allowing the formation of neotissues with good viability of cell growth.
文摘From April 21st to 23rd,the 2025 China Surfactant Industry Conference was successfully held in Hangzhou.The conference was hosted by China Research Institute of Daily Chemical,and the National Engineering Research Center for Surfactant,undertaken by the National Productivity Promotion Center for Surfactant and Detergent Industry and the China Daily Chemical Industry Information Center,specially co-organized by Zanyu Technology Group Co.,Ltd,and jointly co-organized by the China Surface Active Agent Industry Alliance (SAA),the Malaysian Palm Oil Board (MPOB),the Roundtable on Sustainable Palm Oil (RSPO),and the American Oil Chemists’ Society (AOCS).
基金financially supported by the National Natural Science Foundation of China(Nos.42207352,42007020,and 42007015)the Natural Science Fund for Excellent Young Scholars of Hainan Province,China(No.324YXQN421)。
文摘Isomorphic substitution of ferric ion(Fe~(3+))by aluminum ion(Al~(3+))in iron(hydro)oxides is ubiquitous in natural environments.Aluminum substitution inevitably leads to changes in the microstructures,physicochemical properties,and surface reactions of iron(hydro)oxides,which may have great impacts on the sequestration of nutrients and contaminants in soils and aquatic environments.Over the past decades,the structural properties and surface reactivity of Al-substituted iron(hydro)oxides have been intensively studied.Iron(hydro)oxides in various structural forms and with different Al substitution amounts present high application potentials in addressing environmental issues.A timely summary of the structural properties and interfacial reactions of the most common and representative Al-substituted iron(hydro)oxides is of significance.Herein,the effects of Al substitution on the structural properties and surface activities of iron(hydro)oxides were clarified according to the microstructure,crystal facets,surface site type and density,interfacial reaction mechanisms,and modeling parameters of iron(hydro)oxides.This review systematically elucidates how Al substitution affects the structural properties and surface reactions of iron(hydro)oxides,including the well crystallized goethite and hematite and the poorly crystallized ferrihydrite,providing theoretical guidance for further exploration of the mineralogical characteristics and environmental geochemical behaviors of iron(hydro)oxides.
基金supported in part by the National Natural Science Foundation of China under Grant 62071253,Grant 62371252 and Grant 62271268in part by the Jiangsu Provincial Key Research and Development Program under Grant BE2022800in part by the Jiangsu Provincial 333 Talent Project.
文摘This paper considers a multi-antenna ac-cess point(AP)transmitting secrecy message to a single-antenna user in the presence of a single-antenna illegal eavesdropper(Eve)and proposes a double ac-tive reconfigurable intelligent surfaces(DARISs)as-sisted physical layer security(PLS)scheme denoted by DARISs-PLS to protect the secrecy message trans-mission.We formulate a secrecy rate maximization problem for the proposed DARISs-PLS scheme by considering a power budget constraint for the two ac-tive reconfigurable intelligent surfaces(ARISs)and AP.To address the formulated optimization problem,we jointly optimize the reflecting coefficients for the two ARISs and the beamforming at the AP in an it-erative manner by applying Dinkelbach based alter-nating optimization(AO)algorithm and a customized iterative algorithm together with the semidefinite re-laxation(SDR).Numerical results reveal that the pro-posed DARISs-PLS scheme outperforms the dou-ble passive reconfigurable intelligent surfaces-assisted PLS method(DPRISs-PLS)and single ARIS-assisted PLS method(SARIS-PLS)in terms of the secrecy rate.
文摘YAG laser welding with surface activating flux has been investigated, and the influencing factors and mechanism are discussed. The results show that both surface activating flux and surface active element S have fantastic effects on the YAG laser weld shape, that is to obviously increase the weld penetration and D/W ratio in various welding conditions. The mechanism is thought to be the change of weld pool surface tension temperature coefficient, thus, the change of fluid flow pattern in weld pool due to the flux.
基金supported by the National Natural Science Foundation of China(51502221)~~
文摘α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decreased in the order:γ‐MnO2>α‐MnO2>δ‐MnO2>β‐MnO2.The NOx conversion with the use ofγ‐MnO2andα‐MnO2catalysts reached90%in the temperature range of140–200°C,while that based onβ‐MnO2reached only40%at200°C.Theγ‐MnO2andα‐MnO2nanowire crystal morphologies enabled good dispersion of the catalysts and resulted in a relatively high specific surface area.We found thatγ‐MnO2andα‐MnO2possessed stronger reducing abilities and more and stronger acidic sites than the other catalysts.In addition,more chemisorbed oxygen existed on the surface of theγ‐MnO2andα‐MnO2catalysts.Theγ‐MnO2andα‐MnO2catalysts showed excellent performance in the low‐temperature SCR of NO to N2with NH3.
基金the financial support provided by the National Natural Science Foundation of China (No.21573093)the National Key Research and Development Program (No.2017YFB0307501)Guangdong Innovative and Entrepreneurial Research Team Program (No.2013C092)
文摘A novel C/Pb composite has been successfully prepared by electmless plating to reduce the hydrogenevolution and achieve the high reversibility of the anode of lead-carbon battery （LCB）. The depositedlead on the surface of C/Pb composite was found to be uniform and adherent to carbon surface. Becauselead has been stuck on the surface of C/Pb composite, the embedded structure suppresses the hydrogenevolution of lead-carbon anode and strengthens the connection between carbon additive and sponge lead.Compared with the blank anode, the lead-carbon anode with C/Pb composite displays excellent charge-discharge reversibility, which is attributed to the good connection between carbon additives and leadthat has been stuck on the surface of C/Pb composite during the preparation process. The addition of CIPb composite maintains a solid anode structure with high specific surface area and power volume, andthereby, it plays a significant role in the highly reversible lead-carbon anode.
基金the financial support by the Special Fund for Basic Scientific Research of Central Colleges (No.2009KH10)the Beijing Postdoctoral Fund (No. B148)the Green Shoots Plan of Beijing Academy of Science and Technology of China (No. B142)
文摘A series of activated carbons from Taixi anthracite were prepared by steam activation in the presence of KOH and then they were modified by different methods. The regulation of porosity and the modification of surface chemistry were carried out with the aim to improve the benzene adsorption capacity of activated carbon. The influences of KOH and activation process parameters including activation temperature, activation time and steam flow rate on porosity of activated carbon were evaluated, and the effect of modification methods on surface chemistry was investigated. Also, the relationship between benzene adsorption capacity and porosity and surface chemistry was analyzed. Results show that activation temperature is the dominant factor in the activation process; the introduction of KOH into the raw material can enhance the reactivity of char in activation process, meanwhile it shows a negative effect on the porosity development, especially on the mesopore development. Results of FTIR analysis indicate that anthracite-based activated carbon with condensed aromatics and chemically inert oxygen does not present the nature to be surface modified. Besides, benzene adsorption capacity has an approximate linear relationship with surface area and in our preparation, benzene adsorption capacity and surface area of activated carbon are up to 1210 m 2 /g and 423 mg/g, respectively.
文摘Five new zwitterionic surfactants with long chain alkyl betaine structure incorporated with hydroxylpropyl group have been synthesized. Their structures were identified by elemental analysis, IR (HNMR)-H-1, and (CNMR)-C-13. Surface tension experiments showed that these surfactants have higher surface activity than those without hydroxypropyl group. The values of CMC and gamma(CMC) of these surfactants have been determined.
基金the Key Research and Development Project of the Ministry of Science and Technology of China(No.2022YFC3004900)。
文摘Fluorosurfactants are the key ingredients in the formulations of aqueous film-forming foams(AFFFs)for extinguishing flammable liquids,thus developing high-efficient and low-toxic fluorosurfactants is desirable in AFFFs application.Herein,a series of hyperbranched polymeric fluorosu rfactants(HPFs)were successfully synthesized through sequentially modifying hyperbranched polyethylenimine(PEI)with the hydrophilic poly(ethylene glycol)(PEG)chains and the hydrophobic C6/C4-based perfluoroalkyl chains,which were verified by FTIR,^(1)H-and^(19)F-NMR.The surface tensions of all the HPFs in water were measured,and the corresponding physicochemical parameters were interpreted.It was found that the surface activities of HPFs could be tuned through adjusting the ratio of PEG to perfluoroalkyl chains,the length of perfluoroalkyl chains,the molecular weight of PEI core,but not the PEG chain length.In the binary mixture of HPFs with the commercial small molecule fluorosurfactant Capstone^(TM)1157(C1157),a strong synergism led to the elevation of surface activity,which was attributed to the efficient encapsulation of C1157 vips by the compact hyperbranched HPFs as the hosts.The utilization of HPF/C1157 as fluorosurfactant ingredients in AFFF formulations could realize much higher fire-extinguishing efficiency towards flammable oils than the control AFFFs prepa red from the polymeric Capstone^(TM)1460 or the neat C1157.
