The rational design of efficient and stable carbon-based electrocatalysts for oxygen reduction and oxygen evolution reactions is crucial for improving energy density and long-term stability of rechargeable zinc-air ba...The rational design of efficient and stable carbon-based electrocatalysts for oxygen reduction and oxygen evolution reactions is crucial for improving energy density and long-term stability of rechargeable zinc-air batteries(ZABs).Herein,a general and controllable synthesis method was developed to prepare three-dimensional(3D)porous carbon composites embedded with diverse metal phosphide nanocrystallites by interfacial coordination of transition metal ions with phytic acid-doped polyaniline networks and subsequent pyrolysis.Phytic acid as the dopant of polyaniline provides favorable anchoring sites for metal ions owing to the coordination interaction.Specifically,adjusting the concentration of adsorbed cobalt ions can achieve the phase regulation of transition metal phosphides.Thus,with abundant cobalt phosphide nanoparticles and nitrogen-and phosphorus-doping sites,the obtained carbon-based electrocatalysts exhibited efficient electrocatalytic activities toward oxygen reduction and evolution reactions.Consequently,the fabricated ZABs exhibited a high energy density,high power density of 368 mW cm^(-2),and good cycling/mechanical stability,which could power water splitting for integrated device fabrication with high gas yields.展开更多
Ultrafine nano-scale Cu2Sb alloy confined in a three-dimensional porous carbon was synthesized using NaCl template-assisted vacuum freeze-drying followed by high-temperature sintering and was evaluated as an anode for...Ultrafine nano-scale Cu2Sb alloy confined in a three-dimensional porous carbon was synthesized using NaCl template-assisted vacuum freeze-drying followed by high-temperature sintering and was evaluated as an anode for sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs).The alloy exerts excellent cycling durability(the capacity can be maintained at 328.3 mA·h·g^(-1) after 100 cycles for SIBs and 260 mA·h·g^(-1) for PIBs)and rate capability(199 mA·h·g^(-1) at 5 A·g^(-1) for SIBs and 148 mA·h·g^(-1) at 5 A·g^(-1) for PIBs)because of the smooth electron transport path,fast Na/K ion diffusion rate,and restricted volume changes from the synergistic effect of three-dimensional porous carbon networks and the ultrafine bimetallic nanoalloy.This study provides an ingenious design route and a simple preparation method toward exploring a high-property electrode for K-ion and Na-ion batteries,and it also introduces broad application prospects for other electrochemical applications.展开更多
In this work, a CoNxC active sites-rich three-dimensional porous carbon nanofibers network derived from bacterial cellulose and bimetal-ZIFs is prepared via a nucleation growth strategy and a pyrolysis process.The mat...In this work, a CoNxC active sites-rich three-dimensional porous carbon nanofibers network derived from bacterial cellulose and bimetal-ZIFs is prepared via a nucleation growth strategy and a pyrolysis process.The material displays excellent electrocatalytic activity for the oxygen reduction reaction, reaching a high limiting diffusion current density of -7.8 mA cm^(-2), outperforming metal–organic frameworks derived multifunctional electrocatalysts, and oxygen evolution reaction and hydrogen evolution reaction with low overpotentials of 380 and 107 mV, respectively. When the electrochemical properties are further evaluated, the electrocatalyst as an air cathode for Zn-air batteries exhibits a high cycling stability for63 h as well as a maximum power density of 308 mW cm^(-2), which is better than those for most Zn-air batteries reported to date. In addition, a power density of 152 mW cm^(-2) is provided by the solid-state Zn-air batteries, and the cycling stability is outstanding for 24 h. The remarkable electrocatalytic properties are attributed to the synergistic effect of the 3 D porous carbon nanofibers network and abundant inserted CoNxC active sites, which enable the fast transmission of ions and mass and simultaneously provide a large contact area for the electrode/electrolyte.展开更多
Resulting from the development of electric vehicles,high energy-density Li-S batteries have recently attracted ever-increasing attentions worldwide.However,continuous dissolution of cathodic sulfur and followed shuttl...Resulting from the development of electric vehicles,high energy-density Li-S batteries have recently attracted ever-increasing attentions worldwide.However,continuous dissolution of cathodic sulfur and followed shuttle effect of polysulfides lead to very limited service lifetime for currently-applied Li-S batteries.Herein,a 3 D porous graphene aerogel(GA)decorated with high exposure of anatase TiO2(001)nanoplatelets is proposed as robust host to immobilize cathodic sulfur.Compared with commonly used TiO2(101)nanoparticles,the Ti O2(001)nanoplatelets have highly matched lattices with graphene(002)nanosheets,thus facilitating the electronic transfer.The in-site assembled TiO2@GA host exhibits superior sulfur-immobilized capability,which cannot only entrap sulfur by physical confinement,but also capture dissoluble sulfurous species by chemical bonding.The fabricated S@TiO2@GA cathode shows excellent electrochemical performance with high discharge capacity,superior rate capability,and durable cycling stability as well,supposed to be a promising cathode for high-performance Li-S battery applications.展开更多
Graphene-based composites took extensive attraction as electrodes for supercacitors these years.Three-dimensional cross-linking porous graphene(3D rGO-m)was obtained by KOH activation to graphene modified by 1,2,4-tri...Graphene-based composites took extensive attraction as electrodes for supercacitors these years.Three-dimensional cross-linking porous graphene(3D rGO-m)was obtained by KOH activation to graphene modified by 1,2,4-triaminobenzene.3D porous graphene/polyaniline hybrids(3D rGO-m/PANI)was prepared by the in-situ chemical oxidative polymerization.The rGO-m are reconstructed from 2D to 3D porous structure after KOH activation.The PANI nanorod arrays are successfully decorated on the surface of the 3D porous graphene sheets.The specific capacitance of the 3D rGO-m/PANI hybrids reach 985 F/g at 0.5 A/g.The capacitance retention of 3D rGO-m/PANI maintains 90%of its initial capacity after 1000 cycles,while rGO-m/PANI only keeps 83%of its initial capacity,the cycling stability of both hybrids are higher than that of pure PANI(69%).展开更多
Transparent solar-blind ultraviolet photodetectors(SBUV PDs)have extensive applications in versatile scenarios,such as optical communication.However,it is still challenging to simultaneously achieve high responsivity,...Transparent solar-blind ultraviolet photodetectors(SBUV PDs)have extensive applications in versatile scenarios,such as optical communication.However,it is still challenging to simultaneously achieve high responsivity,high transparency,and satisfying self-powered capability.Here,we demonstrated high-performance,transparent,and self-powered photoelectrochemical-type(PEC)SBUV PDs based on vertically grown ultrathin In_(2)O_(3) nanosheet arrays(NAs)with a three-dimensional(3D)porous structure.The 3D porous structure simultaneously improves the transmittance in the visible light region,accelerates interfacial reaction kinetics,and promotes photogenerated carrier transport.The performance of In_(2)O_(3) NAs photoanodes exceeds most reported self-powered PEC SBUV PDs,exhibiting a high transmittance of approximately 80%in the visible light region,a high responsivity of 86.15 mA/W for 254 nm light irradiation,a fast response speed of 15/18 ms,and good multicycle stability.The In_(2)O_(3) NAs also show excellent spectral selectivity with an ultrahigh solar-blind rejection ratio of 1319.30,attributed to the quantum confinement effect induced by the ultrathin feature(2-3 nm).Furthermore,In_(2)O_(3) NAs photoanodes show good capability in underwater optical communication.Our work demonstrated that a 3D porous structure is a powerful strategy to synchronously achieve high responsivity and transparency and provides a new perspective for designing high-performance,transparent,and self-powered PEC SBUV PDs.展开更多
Liposarcoma is one of the most common soft tissue sarcomas,however,its occurrence rate is still rare compared to other cancers.Due to its rarity,in vitro experiments are an essential approach to elucidate liposarcoma ...Liposarcoma is one of the most common soft tissue sarcomas,however,its occurrence rate is still rare compared to other cancers.Due to its rarity,in vitro experiments are an essential approach to elucidate liposarcoma pathobiology.Conventional cell culture-based research(2D cell culture)is still playing a pivotal role,while several shortcomings have been recently under discussion.In vivo,mouse models are usually adopted for pre-clinical analyses with expectations to overcome the issues of 2D cell culture.However,they do not fully recapitulate human dedifferentiated liposarcoma(DDLPS)characteristics.Therefore,three-dimensional(3D)culture systems have been the recent research focus in the cell biology field with the expectation to overcome at the same time the disadvantages of 2D cell culture and in vivo animal models and fill in the gap between them.Given the liposarcoma rarity,we believe that 3D cell culture techniques,including 3D cell cultures/co-cultures,and Patient-Derived tumor Organoids(PDOs),represent a promising approach to facilitate liposarcoma investigation and elucidate its molecular mechanisms and effective therapy development.In this review,we first provide a general overview of 3D cell cultures compared to 2D cell cultures.We then focus on one of the recent 3D cell culture applications,Patient-Derived Organoids(PDOs),summarizing and discussing several PDO methodologies.Finally,we discuss the current and future applications of PDOs to sarcoma,particularly in the field of liposarcoma.展开更多
To address the problem of multi-missile cooperative interception against maneuvering targets at a prespecified impact time and desired Line-of-Sight(LOS)angles in ThreeDimensional(3D)space,this paper proposes a 3D lea...To address the problem of multi-missile cooperative interception against maneuvering targets at a prespecified impact time and desired Line-of-Sight(LOS)angles in ThreeDimensional(3D)space,this paper proposes a 3D leader-following cooperative interception guidance law.First,in the LOS direction of the leader,an impact time-controlled guidance law is derived based on the fixed-time stability theory,which enables the leader to complete the interception task at a prespecified impact time.Next,in the LOS direction of the followers,by introducing a time consensus tracking error function,a fixed-time consensus tracking guidance law is investigated to guarantee the consensus tracking convergence of the time-to-go.Then,in the direction normal to the LOS,by combining the designed global integral sliding mode surface and the second-order Sliding Mode Control(SMC)theory,an innovative 3D LOS-angle-constrained interception guidance law is developed,which eliminates the reaching phase in the traditional sliding mode guidance laws and effectively saves energy consumption.Moreover,it effectively suppresses the chattering phenomenon while avoiding the singularity issue,and compensates for unknown interference caused by target maneuvering online,making it convenient for practical engineering applications.Finally,theoretical proof analysis and multiple sets of numerical simulation results verify the effectiveness,superiority,and robustness of the investigated guidance law.展开更多
In this paper,we study the onset and development of three-dimensional convection in a tilted porous layer saturated with a liquid.The layer is subjected to a gravitational field and a strictly vertical temperature gra...In this paper,we study the onset and development of three-dimensional convection in a tilted porous layer saturated with a liquid.The layer is subjected to a gravitational field and a strictly vertical temperature gradient.Typically,problems of thermal convection in tilted porous media saturated with a liquid are studied by assuming constant different temperatures at the boundaries of the layer,which prevent these systems from supporting conductive(non-convective)states.The boundary conditions considered in the present work allow a conductive state and are representative of typical geological applications.In an earlier work,we carried out a linear stability analysis of the conductive state.It was shown that at any layer tilt angles,the most dangerous type of disturbances are longitudinal rolls.Moreover,a non-zero velocity component exists in z-direction.In the present work,threedimensional non-linear convection regimes are studied.The original three-dimensional problem is reduced to two-dimensional one with an analytical expression for the velocity z-component v_(z)=v_(z)(x,y).It is shown that the critical Rayleigh number values obtained through numerical solutions of the obtained 2D problem by a finite difference method for different layer inclination angles,are in a good agreement with those predicted by the linear theory.The number of convective rolls realized in nonlinear calculations also fits the linear theory predictions for a given cavity geometry.Calculations carried out at low supercriticalities show that a direct bifurcation takes place.With increasing supercriticality,no transitions to other convective regimes are detected.The situation studied in this problem can be observed in oil-bearing rock formations under the influence of a geothermal temperature gradient,where the ensuing fluid convection can affect the distribution of oil throughout the layer.展开更多
The development and exploration of efficient and economical electrocatalysts for oxygen evolution reaction(OER)represents the main bottleneck to unlocking a sustainable energy scenario based on elec trocataly tic wate...The development and exploration of efficient and economical electrocatalysts for oxygen evolution reaction(OER)represents the main bottleneck to unlocking a sustainable energy scenario based on elec trocataly tic water splitting.Nano scale integration of three-dimensional(3D)porous heterostructure with highly dispersed active sites and good structural stability is challenging.Herein,a dual template route is developed to construct the 3D porous SiO_(2)/nitrogen-doped carbon(NC)/Co-carbon nano tubes(CNTs)hetero structure.Importantly,the hard template(SiO_(2) nano spheres)contributes to 3D porous structure,increases the specific surface area,and promotes the contact area of the electrolyte.At the same time,the soft template(basic zinc carbonate)can control the growth of 1D CNTs and facilitate the exposure of the active sites.Apparently,3D porous SiO_(2)/NC/Co-CNTs hetero structure inherits highly dispersed Co nanoparticles coated by NC.CNTs conductive channels and abundant N hetero atoms doping are reasonably constructed by a dual template strategy.Therefore,SiO_(2)/NC/Co-CNTs catalyst provides an extraordinary activity for the OER in alkaline media,with a low overpotential of 298 mV at a current density of 10 mA·cm^(-2).Furthermore,SiO_(2)/NC/Co-CNTs hetero structure enables excellent long-term durability with a 10 mV decay in overpotential after 3000 cyclic voltammetry cycles,and 97%remain in current density over 20 h.It is believed that this dual template strategy can provide a new and simple way to construct a highly dispersed active site in electrocatalysts.展开更多
Developing the alternative supported noble metal catalysts with low cost,high catalytic efficiency,and good resistance toward carbon dioxide and water vapor is critically demanded for the oxidative removal of volatile...Developing the alternative supported noble metal catalysts with low cost,high catalytic efficiency,and good resistance toward carbon dioxide and water vapor is critically demanded for the oxidative removal of volatile organic compounds(VOCs).In this work,we prepared the mesoporous chromia-supported bimetallic Co and Ni single-atom(Co_(1)Ni_(1)/meso-Cr_(2)O_(3))and bimetallic Co and Ni nanoparticle(Co_(NP)Ni_(NP)/mesoCr_(2)O_(3))catalysts adopting the one-pot polyvinyl pyrrolidone(PVP)-and polyvinyl alcohol(PVA)-protecting approaches,respectively.The results indicate that the Co_(1)Ni_(1)/meso-Cr_(2)O_(3)catalyst exhibited the best catalytic activity for n-hexane(C_(6)H_(14))combustion(T_(50%)and T_(90%)were 239 and 263℃ at a space velocity of 40,000 mL g^(-1)h^(-1);apparent activation energy and specific reaction rate at 260℃ were 54.7 kJ mol^(-1)and 4.3×10^(-7)mol g^(-1)_(cat)s^(-1),respectively),which was associated with its higher(Cr^(5+)+Cr^(6+))amount,large n-hexane adsorption capacity,and good lattice oxygen mobility that could enhance the deep oxidation of n-hexane,in which Ni_(1) was beneficial for the enhancements in surface lattice oxygen mobility and low-temperature reducibility,while Co_(1) preferred to generate higher contents of the high-valence states of chromium and surface oxygen species as well as adsorption and activation of n-hexane.n-Hexane combustion takes place via the Mars van Krevelen(MvK)mechanism,and its reaction pathways are as follows:n-hexane→olefins or 3-hexyl hydroperoxide→3-hexanone,2-hexanone or 2,5-dimethyltetrahydrofuran→2-methyloxirane or 2-ethyl-oxetane→acrylic acid→CO_x→CO_(2)and H_(2)O.展开更多
Three-dimensional(3D)ordered mesoporous MnO2 was prepared using KIT-6 mesoporous molecular sieves as a hard template.The material was used for catalytic oxidation of HCHO.The material has high surface areas and the ...Three-dimensional(3D)ordered mesoporous MnO2 was prepared using KIT-6 mesoporous molecular sieves as a hard template.The material was used for catalytic oxidation of HCHO.The material has high surface areas and the mesoporous characteristics of the template,with cubic symmetry(ia3d).It consists of a β-MnO2 crystalline phase corresponding to pyrolusite,with a rutile structure.Transmission electron microscopy and X-ray photoelectron spectroscopy showed that the 3D-MnO2 catalyst has a large number of exposed Mn4+ ions on the(110)crystal plane surfaces,with a lattice spacing of 0.311 nm; this enhances oxidation of HCHO.Complete conversion of HCHO to CO2 and H2O was achieved at 130 °C on 3D-MnO2; the same conversions on α-MnO2 and β-MnO2 nanorods were obtained at 140 and 180 °C,respectively,under the same conditions.The specific mesoporous structure,high specific surface area,and large number of surface Mn4+ ions are responsible for the catalytic activity of 3D-MnO2 in HCHO oxidation.展开更多
Graphite anode materials are widely used in commercial lithium-ion batteries;however, the long electron/ion transportation path restricted its high energy storage. In this experiment, we designed a copper/graphite com...Graphite anode materials are widely used in commercial lithium-ion batteries;however, the long electron/ion transportation path restricted its high energy storage. In this experiment, we designed a copper/graphite composite with a dual three-dimensional(3 D) continuous porous structure combining used nonsolvent-induced phase separation and heat treatment, in which a large amount of graphite is embedded in the 3 D porous copper/carbon architecture. In the novel structure, not only the electron and Li^(+) transmission performances are improved, but also the space of current collector is fully utilized. Meanwhile,carbonized polyacrylonitrile network stabilizes the interface between graphite and copper matrix. The obtained copper/graphite composite anode has an initial discharge capacity of 524.6 mAh·g^(-1), a holding capacity of350 mAh·g^(-1) and excellent cycle stability(299.3 mAh·g^(-1) after 180 cycles at 0.1 C rate), exhibiting good electrochemical performance. The experimental results show that the mass loading of the copper/graphite composite electrode material is about 4.39 mg·cm^(-2). We also envisage replacing graphite with other high-capacity active materials to fill the current collector, which can provide a reference for the future development of next-generation advanced electrodes.展开更多
A series of K-doped Mn0.5Ce0.5Oδ (K-MCO) catalysts with three-dimensionally ordered macroporous (3DOM) structure and different K loadings were successfully synthesized using simple methods. These catalysts exhibi...A series of K-doped Mn0.5Ce0.5Oδ (K-MCO) catalysts with three-dimensionally ordered macroporous (3DOM) structure and different K loadings were successfully synthesized using simple methods. These catalysts exhibited well-defined 3DOM nanostructure, which consisted of extensive interconnecting networks of spherical voids. The effects of the calcination temperature and calcination time on the morphological characteristics and crystalline forms of the catalysts were systematically studied. The catalysts showed high catalytic activity for the combustion of soot. 3DOM 20% K-MCO-4h catalyst, in particular, showed the highest catalytic activity of all of the catalysts studied (e.g., Ts0 = 331 ~C and Smco2 = 95.3%). The occurrence of structural and synergistic effects among the K, Mn, and Ce atoms in the catalysts was favorable for enhancing their catalytic activity towards the combustion of diesel soot. Furthermore, the temperatures required for the complete combustion of the soot (〈400 ℃) were well within the exhaust temperature range (175-400 ℃), which means that the accumulated soot can be removed under the conditions of the diesel exhaust gas. These catalysts could therefore be used in numerous practical applications because they are easy to synthesize, exhibit high catalytic activity, and can be made from low cost materials.展开更多
In order to obtain a better sandstone three-dimensional (3D) reconstruction result which is more similar to the original sample, an algorithm based on stationarity for a two-dimensional (2D) training image is prop...In order to obtain a better sandstone three-dimensional (3D) reconstruction result which is more similar to the original sample, an algorithm based on stationarity for a two-dimensional (2D) training image is proposed. The second-order statistics based on texture features are analyzed to evaluate the scale stationarity of the training image. The multiple-point statistics of the training image are applied to obtain the multiple-point statistics stationarity estimation by the multi-point density function. The results show that the reconstructed 3D structures are closer to reality when the training image has better scale stationarity and multiple-point statistics stationarity by the indications of local percolation probability and two-point probability. Moreover, training images with higher multiple-point statistics stationarity and lower scale stationarity are likely to obtain closer results to the real 3D structure, and vice versa. Thus, stationarity analysis of the training image has far-reaching significance in choosing a better 2D thin section image for the 3D reconstruction of porous media. Especially, high-order statistics perform better than low-order statistics.展开更多
The dual-layer electrode for fuel cells is typically prepared by binding discrete catalyst nanoparticles onto a diffusion layer.Such a random packing forms a dense catalyst layer and thus creates a barrier for mass/io...The dual-layer electrode for fuel cells is typically prepared by binding discrete catalyst nanoparticles onto a diffusion layer.Such a random packing forms a dense catalyst layer and thus creates a barrier for mass/ion transport,particularly for direct liquid fuel cells.Three-dimensional porous electrodes,a thin nano-porous catalyst layer uniformly distributed on the matrix surface of a foam-like structure,are typically employed to improve the mass/ion transport.Such a three-dimensional porous structure brings two critical advantages:(i)reduced mass/ion transport resistance for the delivery of the reactants via shortening the transport distance and(ii)enlarged electrochemical surface area,via reducing the dead pores,isolated particles and severe aggregations,for interfacial reactions.Moreover,the three-dimensional design is capable of fabricating binder-free electrodes,thereby eliminating the use of ionomers/binders and simplifying the fabrication process.In this work,three types of three-dimensional porous electrode are fabricated,via different preparation methods,for direct formate fuel cells:(i)Pd/C nanoparticles coating on the nickel foam matrix surface(Pd-C/NF)via a dip-coating method,(ii)Pd nanoparticles depositing on the nickel foam matrix surface(Pd/NF)via reduction reaction deposition,and(iii)Pd nanoparticles embedding in the nickel foam matrix(Pd/(in)NF)via replacement reaction deposition.The latter two are binder-free three-dimensional porous electrodes.As a comparison,a conventional dual-layer design,Pd/C nanoparticles painting on the nickel foam layer(Pd-C//NF),is also prepared via direct painting method.It is shown that the use of the three-dimensional Pd-C/NF electrode as the anode in a direct formate fuel cell results in a peak power density of 45.0 mW cm^(-2)at 60℃,which is two times of that achieved by using a conventional dual-layer design(19.5 mW cm^(-2)).This performance improvement is mainly attributed to the unique three-dimensional structure design,which effectively enhances the mass/ion transport through the porous electrode and enlarges the electrochemical surface area(accessible active area)for interfacial reactions.In addition,the delivery of the fuel solution is still sufficient even when the flow rate is as low as 2.0 mL min^(-1).It is also demonstrated that direct formate fuel cells using two binder-free electrodes yield the peak power densities of 13.5 mW cm^(-2)(Pd/(in)NF)and 14.0 mW cm^(-2)(Pd/NF)at 60℃,respectively,both of which are much lower than the power density achieved by using the Pd-C/NF electrode.This is because the electrochemical surface areas of two binderfree electrodes are much smaller than the Pd/C-based electrodes,since the specific area of Pd/C nanoparticles is much larger.展开更多
Finding inexpensive electrodes with high activity and stability is key to realize the practical application of fuel cells. Here, we report the fabrication of three-dimensional (3D) porous nickel nanoflower (3D-PNNF...Finding inexpensive electrodes with high activity and stability is key to realize the practical application of fuel cells. Here, we report the fabrication of three-dimensional (3D) porous nickel nanoflower (3D-PNNF) electrodes via an in situ reduction method. The 3D-PNNF electrodes have a high surface area, show tight binding to the electroconductive substrate, and most importantly, have superaerophobic (bubble repellent) surfaces. Therefore, the electrocatalytic hydrazine oxidation performance of the 3D-PNNF electrodes was much higher than that of commercial Pt/C catalysts because of its ultra-weak gas-bubble adhesion and ultra-fast gas-bubble release. Furthermore, the 3D-PNNF electrodes showed ultra-high stability even under a high current density (260 mA/cm^2), which makes it promising for practical applications. In addition, the construction of superaerophobic nanostructures could also be beneficial for other gas evolution processes (e.g., hydrogen evolution reaction).展开更多
Through combined applications of the transfer-matrix method and asymptotic expansion technique,we formulate a theory to predict the three-dimensional response of micropolar plates.No ad hoc assumptions regarding throu...Through combined applications of the transfer-matrix method and asymptotic expansion technique,we formulate a theory to predict the three-dimensional response of micropolar plates.No ad hoc assumptions regarding through-thickness assumptions of the field variables are made,and the governing equations are two-dimensional,with the displacements and microrotations of the mid-plane as the unknowns.Once the deformation of the mid-plane is solved,a three-dimensional micropolar elastic field within the plate is generated,which is exact up to the second order except in the boundary region close to the plate edge.As an illustrative example,the bending of a clamped infinitely long plate caused by a uniformly distributed transverse force is analyzed and discussed in detail.展开更多
BACKGROUND Biliary stone disease is a highly prevalent condition and a leading cause of hospitalization worldwide.Hepatolithiasis with associated strictures has high residual and recurrence rates after traditional mul...BACKGROUND Biliary stone disease is a highly prevalent condition and a leading cause of hospitalization worldwide.Hepatolithiasis with associated strictures has high residual and recurrence rates after traditional multisession percutaneous transhepatic cholangioscopic lithotripsy(PTCSL).AIM To study one-step PTCSL using the percutaneous transhepatic one-step biliary fistulation(PTOBF)technique guided by three-dimensional(3D)visualization.METHODS This was a retrospective,single-center study analyzing,140 patients who,between October 2016 and October 2023,underwent one-step PTCSL for hepatolithiasis.The patients were divided into two groups:The 3D-PTOBF group and the PTOBF group.Stone clearance on choledochoscopy,complications,and long-term clearance and recurrence rates were assessed.RESULTS Age,total bilirubin,direct bilirubin,Child-Pugh class,and stone location were similar between the 2 groups,but there was a significant difference in bile duct strictures,with biliary strictures more common in the 3D-PTOBF group(P=0.001).The median follow-up time was 55.0(55.0,512.0)days.The immediate stone clearance ratio(88.6%vs 27.1%,P=0.000)and stricture resolution ratio(97.1%vs 78.6%,P=0.001)in the 3D-PTOBF group were significantly greater than those in the PTOBF group.Postoperative complication(8.6%vs 41.4%,P=0.000)and stone recurrence rates(7.1%vs 38.6%,P=0.000)were significantly lower in the 3D-PTOBF group.CONCLUSION Three-dimensional visualization helps make one-step PTCSL a safe,effective,and promising treatment for patients with complicated primary hepatolithiasis.The perioperative and long-term outcomes are satisfactory for patients with complicated primary hepatolithiasis.This minimally invasive method has the potential to be used as a substitute for hepatobiliary surgery.展开更多
Hypoxia is a typical feature of the tumor microenvironment,one of the most critical factors affecting cell behavior and tumor progression.However,the lack of tumor models able to precisely emulate natural brain tumor ...Hypoxia is a typical feature of the tumor microenvironment,one of the most critical factors affecting cell behavior and tumor progression.However,the lack of tumor models able to precisely emulate natural brain tumor tissue has impeded the study of the effects of hypoxia on the progression and growth of tumor cells.This study reports a three-dimensional(3D)brain tumor model obtained by encapsulating U87MG(U87)cells in a hydrogel containing type I collagen.It also documents the effect of various oxygen concentrations(1%,7%,and 21%)in the culture environment on U87 cell morphology,proliferation,viability,cell cycle,apoptosis rate,and migration.Finally,it compares two-dimensional(2D)and 3D cultures.For comparison purposes,cells cultured in flat culture dishes were used as the control(2D model).Cells cultured in the 3D model proliferated more slowly but had a higher apoptosis rate and proportion of cells in the resting phase(G0 phase)/gap I phase(G1 phase)than those cultured in the 2D model.Besides,the two models yielded significantly different cell morphologies.Finally,hypoxia(e.g.,1%O2)affected cell morphology,slowed cell growth,reduced cell viability,and increased the apoptosis rate in the 3D model.These results indicate that the constructed 3D model is effective for investigating the effects of biological and chemical factors on cell morphology and function,and can be more representative of the tumor microenvironment than 2D culture systems.The developed 3D glioblastoma tumor model is equally applicable to other studies in pharmacology and pathology.展开更多
文摘The rational design of efficient and stable carbon-based electrocatalysts for oxygen reduction and oxygen evolution reactions is crucial for improving energy density and long-term stability of rechargeable zinc-air batteries(ZABs).Herein,a general and controllable synthesis method was developed to prepare three-dimensional(3D)porous carbon composites embedded with diverse metal phosphide nanocrystallites by interfacial coordination of transition metal ions with phytic acid-doped polyaniline networks and subsequent pyrolysis.Phytic acid as the dopant of polyaniline provides favorable anchoring sites for metal ions owing to the coordination interaction.Specifically,adjusting the concentration of adsorbed cobalt ions can achieve the phase regulation of transition metal phosphides.Thus,with abundant cobalt phosphide nanoparticles and nitrogen-and phosphorus-doping sites,the obtained carbon-based electrocatalysts exhibited efficient electrocatalytic activities toward oxygen reduction and evolution reactions.Consequently,the fabricated ZABs exhibited a high energy density,high power density of 368 mW cm^(-2),and good cycling/mechanical stability,which could power water splitting for integrated device fabrication with high gas yields.
基金financially supported by the National Natural Science Foundation of China(Nos.51871046,51902046,52071073,51874079,51571054,51771046,and 51674068)the Natural Science Foundation of Liaoning Province,China(No.201602257)+2 种基金Natural Science Foundation of Hebei Province,China(Nos.E2019501097,E2018501091,E2020501004)the Science and Technology Project of Hebei Province,China(No.15271302D)the Fundamental Research Funds for the Central Universities,China(Nos.N182304017,N182304015,N172302001,N172304044).
文摘Ultrafine nano-scale Cu2Sb alloy confined in a three-dimensional porous carbon was synthesized using NaCl template-assisted vacuum freeze-drying followed by high-temperature sintering and was evaluated as an anode for sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs).The alloy exerts excellent cycling durability(the capacity can be maintained at 328.3 mA·h·g^(-1) after 100 cycles for SIBs and 260 mA·h·g^(-1) for PIBs)and rate capability(199 mA·h·g^(-1) at 5 A·g^(-1) for SIBs and 148 mA·h·g^(-1) at 5 A·g^(-1) for PIBs)because of the smooth electron transport path,fast Na/K ion diffusion rate,and restricted volume changes from the synergistic effect of three-dimensional porous carbon networks and the ultrafine bimetallic nanoalloy.This study provides an ingenious design route and a simple preparation method toward exploring a high-property electrode for K-ion and Na-ion batteries,and it also introduces broad application prospects for other electrochemical applications.
基金financial support from the following sources: the National Natural Science Foundation of China (NSFC) (Grants 51607054, 51772073)Young Talent of Hebei Province (Nos. 70280011808, 70280016160250)+1 种基金Hebei Province Outstanding Youth Fund (A2018201019, A2017201082)Hebei Province Natural Science Fund (A2015201050)。
文摘In this work, a CoNxC active sites-rich three-dimensional porous carbon nanofibers network derived from bacterial cellulose and bimetal-ZIFs is prepared via a nucleation growth strategy and a pyrolysis process.The material displays excellent electrocatalytic activity for the oxygen reduction reaction, reaching a high limiting diffusion current density of -7.8 mA cm^(-2), outperforming metal–organic frameworks derived multifunctional electrocatalysts, and oxygen evolution reaction and hydrogen evolution reaction with low overpotentials of 380 and 107 mV, respectively. When the electrochemical properties are further evaluated, the electrocatalyst as an air cathode for Zn-air batteries exhibits a high cycling stability for63 h as well as a maximum power density of 308 mW cm^(-2), which is better than those for most Zn-air batteries reported to date. In addition, a power density of 152 mW cm^(-2) is provided by the solid-state Zn-air batteries, and the cycling stability is outstanding for 24 h. The remarkable electrocatalytic properties are attributed to the synergistic effect of the 3 D porous carbon nanofibers network and abundant inserted CoNxC active sites, which enable the fast transmission of ions and mass and simultaneously provide a large contact area for the electrode/electrolyte.
基金financially supported by the National Key R and D Program of China(No.2019YFA0210300)the Hunan Provincial Natural Science Foundation of China(No.2019JJ40359)+1 种基金the Hunan Provincial S and T Plan of China(Nos.2017TP1001,2016TP1007)the Open-End Fund for the Valuable and Precision Instruments of Central South University(CSUZC2020016)。
文摘Resulting from the development of electric vehicles,high energy-density Li-S batteries have recently attracted ever-increasing attentions worldwide.However,continuous dissolution of cathodic sulfur and followed shuttle effect of polysulfides lead to very limited service lifetime for currently-applied Li-S batteries.Herein,a 3 D porous graphene aerogel(GA)decorated with high exposure of anatase TiO2(001)nanoplatelets is proposed as robust host to immobilize cathodic sulfur.Compared with commonly used TiO2(101)nanoparticles,the Ti O2(001)nanoplatelets have highly matched lattices with graphene(002)nanosheets,thus facilitating the electronic transfer.The in-site assembled TiO2@GA host exhibits superior sulfur-immobilized capability,which cannot only entrap sulfur by physical confinement,but also capture dissoluble sulfurous species by chemical bonding.The fabricated S@TiO2@GA cathode shows excellent electrochemical performance with high discharge capacity,superior rate capability,and durable cycling stability as well,supposed to be a promising cathode for high-performance Li-S battery applications.
基金This work was financially supported by the Program of National Natural Science Foundation of China(No.51472166)Liaoning BaiQianWan Talents program.
文摘Graphene-based composites took extensive attraction as electrodes for supercacitors these years.Three-dimensional cross-linking porous graphene(3D rGO-m)was obtained by KOH activation to graphene modified by 1,2,4-triaminobenzene.3D porous graphene/polyaniline hybrids(3D rGO-m/PANI)was prepared by the in-situ chemical oxidative polymerization.The rGO-m are reconstructed from 2D to 3D porous structure after KOH activation.The PANI nanorod arrays are successfully decorated on the surface of the 3D porous graphene sheets.The specific capacitance of the 3D rGO-m/PANI hybrids reach 985 F/g at 0.5 A/g.The capacitance retention of 3D rGO-m/PANI maintains 90%of its initial capacity after 1000 cycles,while rGO-m/PANI only keeps 83%of its initial capacity,the cycling stability of both hybrids are higher than that of pure PANI(69%).
基金support from Fundamental Research Funds for the Central Universities(No.2572023AW26)the Innovation Foundation for the Doctoral Program of Forestry Engineering of Northeast Forestry University(No.LYGC202227).
文摘Transparent solar-blind ultraviolet photodetectors(SBUV PDs)have extensive applications in versatile scenarios,such as optical communication.However,it is still challenging to simultaneously achieve high responsivity,high transparency,and satisfying self-powered capability.Here,we demonstrated high-performance,transparent,and self-powered photoelectrochemical-type(PEC)SBUV PDs based on vertically grown ultrathin In_(2)O_(3) nanosheet arrays(NAs)with a three-dimensional(3D)porous structure.The 3D porous structure simultaneously improves the transmittance in the visible light region,accelerates interfacial reaction kinetics,and promotes photogenerated carrier transport.The performance of In_(2)O_(3) NAs photoanodes exceeds most reported self-powered PEC SBUV PDs,exhibiting a high transmittance of approximately 80%in the visible light region,a high responsivity of 86.15 mA/W for 254 nm light irradiation,a fast response speed of 15/18 ms,and good multicycle stability.The In_(2)O_(3) NAs also show excellent spectral selectivity with an ultrahigh solar-blind rejection ratio of 1319.30,attributed to the quantum confinement effect induced by the ultrathin feature(2-3 nm).Furthermore,In_(2)O_(3) NAs photoanodes show good capability in underwater optical communication.Our work demonstrated that a 3D porous structure is a powerful strategy to synchronously achieve high responsivity and transparency and provides a new perspective for designing high-performance,transparent,and self-powered PEC SBUV PDs.
文摘Liposarcoma is one of the most common soft tissue sarcomas,however,its occurrence rate is still rare compared to other cancers.Due to its rarity,in vitro experiments are an essential approach to elucidate liposarcoma pathobiology.Conventional cell culture-based research(2D cell culture)is still playing a pivotal role,while several shortcomings have been recently under discussion.In vivo,mouse models are usually adopted for pre-clinical analyses with expectations to overcome the issues of 2D cell culture.However,they do not fully recapitulate human dedifferentiated liposarcoma(DDLPS)characteristics.Therefore,three-dimensional(3D)culture systems have been the recent research focus in the cell biology field with the expectation to overcome at the same time the disadvantages of 2D cell culture and in vivo animal models and fill in the gap between them.Given the liposarcoma rarity,we believe that 3D cell culture techniques,including 3D cell cultures/co-cultures,and Patient-Derived tumor Organoids(PDOs),represent a promising approach to facilitate liposarcoma investigation and elucidate its molecular mechanisms and effective therapy development.In this review,we first provide a general overview of 3D cell cultures compared to 2D cell cultures.We then focus on one of the recent 3D cell culture applications,Patient-Derived Organoids(PDOs),summarizing and discussing several PDO methodologies.Finally,we discuss the current and future applications of PDOs to sarcoma,particularly in the field of liposarcoma.
文摘To address the problem of multi-missile cooperative interception against maneuvering targets at a prespecified impact time and desired Line-of-Sight(LOS)angles in ThreeDimensional(3D)space,this paper proposes a 3D leader-following cooperative interception guidance law.First,in the LOS direction of the leader,an impact time-controlled guidance law is derived based on the fixed-time stability theory,which enables the leader to complete the interception task at a prespecified impact time.Next,in the LOS direction of the followers,by introducing a time consensus tracking error function,a fixed-time consensus tracking guidance law is investigated to guarantee the consensus tracking convergence of the time-to-go.Then,in the direction normal to the LOS,by combining the designed global integral sliding mode surface and the second-order Sliding Mode Control(SMC)theory,an innovative 3D LOS-angle-constrained interception guidance law is developed,which eliminates the reaching phase in the traditional sliding mode guidance laws and effectively saves energy consumption.Moreover,it effectively suppresses the chattering phenomenon while avoiding the singularity issue,and compensates for unknown interference caused by target maneuvering online,making it convenient for practical engineering applications.Finally,theoretical proof analysis and multiple sets of numerical simulation results verify the effectiveness,superiority,and robustness of the investigated guidance law.
基金financial support from the Ministry of Science and Higher Education of the Russian Federation(Topic No.121031700169-1).
文摘In this paper,we study the onset and development of three-dimensional convection in a tilted porous layer saturated with a liquid.The layer is subjected to a gravitational field and a strictly vertical temperature gradient.Typically,problems of thermal convection in tilted porous media saturated with a liquid are studied by assuming constant different temperatures at the boundaries of the layer,which prevent these systems from supporting conductive(non-convective)states.The boundary conditions considered in the present work allow a conductive state and are representative of typical geological applications.In an earlier work,we carried out a linear stability analysis of the conductive state.It was shown that at any layer tilt angles,the most dangerous type of disturbances are longitudinal rolls.Moreover,a non-zero velocity component exists in z-direction.In the present work,threedimensional non-linear convection regimes are studied.The original three-dimensional problem is reduced to two-dimensional one with an analytical expression for the velocity z-component v_(z)=v_(z)(x,y).It is shown that the critical Rayleigh number values obtained through numerical solutions of the obtained 2D problem by a finite difference method for different layer inclination angles,are in a good agreement with those predicted by the linear theory.The number of convective rolls realized in nonlinear calculations also fits the linear theory predictions for a given cavity geometry.Calculations carried out at low supercriticalities show that a direct bifurcation takes place.With increasing supercriticality,no transitions to other convective regimes are detected.The situation studied in this problem can be observed in oil-bearing rock formations under the influence of a geothermal temperature gradient,where the ensuing fluid convection can affect the distribution of oil throughout the layer.
基金supported by the National Natural Science Foundation of China(No.22269010)Jiangxi Provincial Natural Science Foundation(No.20224BAB214021)+1 种基金the Training Program for Academic and Technical Leaders of Major Disciplines in Jiangxi Province(No.20212BCJ23020)the Science and Technology Project of Jiangxi Provincial Department of Education(No.GJJ211305)。
文摘The development and exploration of efficient and economical electrocatalysts for oxygen evolution reaction(OER)represents the main bottleneck to unlocking a sustainable energy scenario based on elec trocataly tic water splitting.Nano scale integration of three-dimensional(3D)porous heterostructure with highly dispersed active sites and good structural stability is challenging.Herein,a dual template route is developed to construct the 3D porous SiO_(2)/nitrogen-doped carbon(NC)/Co-carbon nano tubes(CNTs)hetero structure.Importantly,the hard template(SiO_(2) nano spheres)contributes to 3D porous structure,increases the specific surface area,and promotes the contact area of the electrolyte.At the same time,the soft template(basic zinc carbonate)can control the growth of 1D CNTs and facilitate the exposure of the active sites.Apparently,3D porous SiO_(2)/NC/Co-CNTs hetero structure inherits highly dispersed Co nanoparticles coated by NC.CNTs conductive channels and abundant N hetero atoms doping are reasonably constructed by a dual template strategy.Therefore,SiO_(2)/NC/Co-CNTs catalyst provides an extraordinary activity for the OER in alkaline media,with a low overpotential of 298 mV at a current density of 10 mA·cm^(-2).Furthermore,SiO_(2)/NC/Co-CNTs hetero structure enables excellent long-term durability with a 10 mV decay in overpotential after 3000 cyclic voltammetry cycles,and 97%remain in current density over 20 h.It is believed that this dual template strategy can provide a new and simple way to construct a highly dispersed active site in electrocatalysts.
基金supported by the National Natural Science Committee of China-Liaoning Provincial People's Government Joint Fund(U1908204)National Natural Science Foundation of China(21876006,21976009,and 21961160743)+2 种基金Foundation on the Creative Research Team Construction Promotion Project of Beijing Municipal Institutions(IDHT20190503)Natural Science Foundation of Beijing Municipal Commission of Education(KM201710005004)Development Program for the Youth Outstanding-Notch Talent of Beijing Municipal Commission of Education(CIT&TCD201904019)。
文摘Developing the alternative supported noble metal catalysts with low cost,high catalytic efficiency,and good resistance toward carbon dioxide and water vapor is critically demanded for the oxidative removal of volatile organic compounds(VOCs).In this work,we prepared the mesoporous chromia-supported bimetallic Co and Ni single-atom(Co_(1)Ni_(1)/meso-Cr_(2)O_(3))and bimetallic Co and Ni nanoparticle(Co_(NP)Ni_(NP)/mesoCr_(2)O_(3))catalysts adopting the one-pot polyvinyl pyrrolidone(PVP)-and polyvinyl alcohol(PVA)-protecting approaches,respectively.The results indicate that the Co_(1)Ni_(1)/meso-Cr_(2)O_(3)catalyst exhibited the best catalytic activity for n-hexane(C_(6)H_(14))combustion(T_(50%)and T_(90%)were 239 and 263℃ at a space velocity of 40,000 mL g^(-1)h^(-1);apparent activation energy and specific reaction rate at 260℃ were 54.7 kJ mol^(-1)and 4.3×10^(-7)mol g^(-1)_(cat)s^(-1),respectively),which was associated with its higher(Cr^(5+)+Cr^(6+))amount,large n-hexane adsorption capacity,and good lattice oxygen mobility that could enhance the deep oxidation of n-hexane,in which Ni_(1) was beneficial for the enhancements in surface lattice oxygen mobility and low-temperature reducibility,while Co_(1) preferred to generate higher contents of the high-valence states of chromium and surface oxygen species as well as adsorption and activation of n-hexane.n-Hexane combustion takes place via the Mars van Krevelen(MvK)mechanism,and its reaction pathways are as follows:n-hexane→olefins or 3-hexyl hydroperoxide→3-hexanone,2-hexanone or 2,5-dimethyltetrahydrofuran→2-methyloxirane or 2-ethyl-oxetane→acrylic acid→CO_x→CO_(2)and H_(2)O.
基金supported by the National Natural Science Foundation of China(21325731,21221004 and 51478241)~~
文摘Three-dimensional(3D)ordered mesoporous MnO2 was prepared using KIT-6 mesoporous molecular sieves as a hard template.The material was used for catalytic oxidation of HCHO.The material has high surface areas and the mesoporous characteristics of the template,with cubic symmetry(ia3d).It consists of a β-MnO2 crystalline phase corresponding to pyrolusite,with a rutile structure.Transmission electron microscopy and X-ray photoelectron spectroscopy showed that the 3D-MnO2 catalyst has a large number of exposed Mn4+ ions on the(110)crystal plane surfaces,with a lattice spacing of 0.311 nm; this enhances oxidation of HCHO.Complete conversion of HCHO to CO2 and H2O was achieved at 130 °C on 3D-MnO2; the same conversions on α-MnO2 and β-MnO2 nanorods were obtained at 140 and 180 °C,respectively,under the same conditions.The specific mesoporous structure,high specific surface area,and large number of surface Mn4+ ions are responsible for the catalytic activity of 3D-MnO2 in HCHO oxidation.
基金financially supported by Tianjin Municipal Education Committee Scientific Research Project (No.2017KJ075)。
文摘Graphite anode materials are widely used in commercial lithium-ion batteries;however, the long electron/ion transportation path restricted its high energy storage. In this experiment, we designed a copper/graphite composite with a dual three-dimensional(3 D) continuous porous structure combining used nonsolvent-induced phase separation and heat treatment, in which a large amount of graphite is embedded in the 3 D porous copper/carbon architecture. In the novel structure, not only the electron and Li^(+) transmission performances are improved, but also the space of current collector is fully utilized. Meanwhile,carbonized polyacrylonitrile network stabilizes the interface between graphite and copper matrix. The obtained copper/graphite composite anode has an initial discharge capacity of 524.6 mAh·g^(-1), a holding capacity of350 mAh·g^(-1) and excellent cycle stability(299.3 mAh·g^(-1) after 180 cycles at 0.1 C rate), exhibiting good electrochemical performance. The experimental results show that the mass loading of the copper/graphite composite electrode material is about 4.39 mg·cm^(-2). We also envisage replacing graphite with other high-capacity active materials to fill the current collector, which can provide a reference for the future development of next-generation advanced electrodes.
基金supported by the National Natural Science Foundation of China(21177160,21303263,21477164)Beijing Nova Program(Z141109001814072)+1 种基金Specialized Research Fund for the Doctoral Program of High Education of China(20130007120011)the Science Foundation of China University of Petroleum-Beijing(2462013YJRC13,2462013BJRC003)~~
文摘A series of K-doped Mn0.5Ce0.5Oδ (K-MCO) catalysts with three-dimensionally ordered macroporous (3DOM) structure and different K loadings were successfully synthesized using simple methods. These catalysts exhibited well-defined 3DOM nanostructure, which consisted of extensive interconnecting networks of spherical voids. The effects of the calcination temperature and calcination time on the morphological characteristics and crystalline forms of the catalysts were systematically studied. The catalysts showed high catalytic activity for the combustion of soot. 3DOM 20% K-MCO-4h catalyst, in particular, showed the highest catalytic activity of all of the catalysts studied (e.g., Ts0 = 331 ~C and Smco2 = 95.3%). The occurrence of structural and synergistic effects among the K, Mn, and Ce atoms in the catalysts was favorable for enhancing their catalytic activity towards the combustion of diesel soot. Furthermore, the temperatures required for the complete combustion of the soot (〈400 ℃) were well within the exhaust temperature range (175-400 ℃), which means that the accumulated soot can be removed under the conditions of the diesel exhaust gas. These catalysts could therefore be used in numerous practical applications because they are easy to synthesize, exhibit high catalytic activity, and can be made from low cost materials.
基金The National Natural Science Foundation of China(No.60972130)
文摘In order to obtain a better sandstone three-dimensional (3D) reconstruction result which is more similar to the original sample, an algorithm based on stationarity for a two-dimensional (2D) training image is proposed. The second-order statistics based on texture features are analyzed to evaluate the scale stationarity of the training image. The multiple-point statistics of the training image are applied to obtain the multiple-point statistics stationarity estimation by the multi-point density function. The results show that the reconstructed 3D structures are closer to reality when the training image has better scale stationarity and multiple-point statistics stationarity by the indications of local percolation probability and two-point probability. Moreover, training images with higher multiple-point statistics stationarity and lower scale stationarity are likely to obtain closer results to the real 3D structure, and vice versa. Thus, stationarity analysis of the training image has far-reaching significance in choosing a better 2D thin section image for the 3D reconstruction of porous media. Especially, high-order statistics perform better than low-order statistics.
基金supported by the Research Grants Council of the Hong Kong Special Administrative Region,China(Grant No.25211817)。
文摘The dual-layer electrode for fuel cells is typically prepared by binding discrete catalyst nanoparticles onto a diffusion layer.Such a random packing forms a dense catalyst layer and thus creates a barrier for mass/ion transport,particularly for direct liquid fuel cells.Three-dimensional porous electrodes,a thin nano-porous catalyst layer uniformly distributed on the matrix surface of a foam-like structure,are typically employed to improve the mass/ion transport.Such a three-dimensional porous structure brings two critical advantages:(i)reduced mass/ion transport resistance for the delivery of the reactants via shortening the transport distance and(ii)enlarged electrochemical surface area,via reducing the dead pores,isolated particles and severe aggregations,for interfacial reactions.Moreover,the three-dimensional design is capable of fabricating binder-free electrodes,thereby eliminating the use of ionomers/binders and simplifying the fabrication process.In this work,three types of three-dimensional porous electrode are fabricated,via different preparation methods,for direct formate fuel cells:(i)Pd/C nanoparticles coating on the nickel foam matrix surface(Pd-C/NF)via a dip-coating method,(ii)Pd nanoparticles depositing on the nickel foam matrix surface(Pd/NF)via reduction reaction deposition,and(iii)Pd nanoparticles embedding in the nickel foam matrix(Pd/(in)NF)via replacement reaction deposition.The latter two are binder-free three-dimensional porous electrodes.As a comparison,a conventional dual-layer design,Pd/C nanoparticles painting on the nickel foam layer(Pd-C//NF),is also prepared via direct painting method.It is shown that the use of the three-dimensional Pd-C/NF electrode as the anode in a direct formate fuel cell results in a peak power density of 45.0 mW cm^(-2)at 60℃,which is two times of that achieved by using a conventional dual-layer design(19.5 mW cm^(-2)).This performance improvement is mainly attributed to the unique three-dimensional structure design,which effectively enhances the mass/ion transport through the porous electrode and enlarges the electrochemical surface area(accessible active area)for interfacial reactions.In addition,the delivery of the fuel solution is still sufficient even when the flow rate is as low as 2.0 mL min^(-1).It is also demonstrated that direct formate fuel cells using two binder-free electrodes yield the peak power densities of 13.5 mW cm^(-2)(Pd/(in)NF)and 14.0 mW cm^(-2)(Pd/NF)at 60℃,respectively,both of which are much lower than the power density achieved by using the Pd-C/NF electrode.This is because the electrochemical surface areas of two binderfree electrodes are much smaller than the Pd/C-based electrodes,since the specific area of Pd/C nanoparticles is much larger.
基金This work was supported by the National Natural Science Foundation of China (Nos. 21271018 and 21125101), the National Basic Research Program of China (No. 2011CBA00503), the National High-tech R&D Program of China (No. 2012AA03A609) and the Program for Changjiang Scholars and Innovative Research Team in University.
文摘Finding inexpensive electrodes with high activity and stability is key to realize the practical application of fuel cells. Here, we report the fabrication of three-dimensional (3D) porous nickel nanoflower (3D-PNNF) electrodes via an in situ reduction method. The 3D-PNNF electrodes have a high surface area, show tight binding to the electroconductive substrate, and most importantly, have superaerophobic (bubble repellent) surfaces. Therefore, the electrocatalytic hydrazine oxidation performance of the 3D-PNNF electrodes was much higher than that of commercial Pt/C catalysts because of its ultra-weak gas-bubble adhesion and ultra-fast gas-bubble release. Furthermore, the 3D-PNNF electrodes showed ultra-high stability even under a high current density (260 mA/cm^2), which makes it promising for practical applications. In addition, the construction of superaerophobic nanostructures could also be beneficial for other gas evolution processes (e.g., hydrogen evolution reaction).
基金Project supported by the National Natural Science Foundation of China (No. 12072337)。
文摘Through combined applications of the transfer-matrix method and asymptotic expansion technique,we formulate a theory to predict the three-dimensional response of micropolar plates.No ad hoc assumptions regarding through-thickness assumptions of the field variables are made,and the governing equations are two-dimensional,with the displacements and microrotations of the mid-plane as the unknowns.Once the deformation of the mid-plane is solved,a three-dimensional micropolar elastic field within the plate is generated,which is exact up to the second order except in the boundary region close to the plate edge.As an illustrative example,the bending of a clamped infinitely long plate caused by a uniformly distributed transverse force is analyzed and discussed in detail.
基金Supported by The Key Medical Specialty Nurturing Program of Foshan During The 14th Five-Year Plan Period,No.FSPY145205The Medical Research Project of Foshan Health Bureau,No.20230814A010024+1 种基金The Guangzhou Science and Technology Plan Project,No.202102010251the Guangdong Science and Technology Program,No.2017ZC0222.
文摘BACKGROUND Biliary stone disease is a highly prevalent condition and a leading cause of hospitalization worldwide.Hepatolithiasis with associated strictures has high residual and recurrence rates after traditional multisession percutaneous transhepatic cholangioscopic lithotripsy(PTCSL).AIM To study one-step PTCSL using the percutaneous transhepatic one-step biliary fistulation(PTOBF)technique guided by three-dimensional(3D)visualization.METHODS This was a retrospective,single-center study analyzing,140 patients who,between October 2016 and October 2023,underwent one-step PTCSL for hepatolithiasis.The patients were divided into two groups:The 3D-PTOBF group and the PTOBF group.Stone clearance on choledochoscopy,complications,and long-term clearance and recurrence rates were assessed.RESULTS Age,total bilirubin,direct bilirubin,Child-Pugh class,and stone location were similar between the 2 groups,but there was a significant difference in bile duct strictures,with biliary strictures more common in the 3D-PTOBF group(P=0.001).The median follow-up time was 55.0(55.0,512.0)days.The immediate stone clearance ratio(88.6%vs 27.1%,P=0.000)and stricture resolution ratio(97.1%vs 78.6%,P=0.001)in the 3D-PTOBF group were significantly greater than those in the PTOBF group.Postoperative complication(8.6%vs 41.4%,P=0.000)and stone recurrence rates(7.1%vs 38.6%,P=0.000)were significantly lower in the 3D-PTOBF group.CONCLUSION Three-dimensional visualization helps make one-step PTCSL a safe,effective,and promising treatment for patients with complicated primary hepatolithiasis.The perioperative and long-term outcomes are satisfactory for patients with complicated primary hepatolithiasis.This minimally invasive method has the potential to be used as a substitute for hepatobiliary surgery.
基金supported by the National Natural Science Foundation of China (No. 52275291)the Fundamental Research Funds for the Central Universitiesthe Program for Innovation Team of Shaanxi Province,China (No. 2023-CX-TD-17)
文摘Hypoxia is a typical feature of the tumor microenvironment,one of the most critical factors affecting cell behavior and tumor progression.However,the lack of tumor models able to precisely emulate natural brain tumor tissue has impeded the study of the effects of hypoxia on the progression and growth of tumor cells.This study reports a three-dimensional(3D)brain tumor model obtained by encapsulating U87MG(U87)cells in a hydrogel containing type I collagen.It also documents the effect of various oxygen concentrations(1%,7%,and 21%)in the culture environment on U87 cell morphology,proliferation,viability,cell cycle,apoptosis rate,and migration.Finally,it compares two-dimensional(2D)and 3D cultures.For comparison purposes,cells cultured in flat culture dishes were used as the control(2D model).Cells cultured in the 3D model proliferated more slowly but had a higher apoptosis rate and proportion of cells in the resting phase(G0 phase)/gap I phase(G1 phase)than those cultured in the 2D model.Besides,the two models yielded significantly different cell morphologies.Finally,hypoxia(e.g.,1%O2)affected cell morphology,slowed cell growth,reduced cell viability,and increased the apoptosis rate in the 3D model.These results indicate that the constructed 3D model is effective for investigating the effects of biological and chemical factors on cell morphology and function,and can be more representative of the tumor microenvironment than 2D culture systems.The developed 3D glioblastoma tumor model is equally applicable to other studies in pharmacology and pathology.