This study evaluated the adhesion of zirconia core ceramics with their corresponding veneering ceramics, having different thermal expansion coefficients (TECs), when zirconia ceramics were coloured at green stage. Z...This study evaluated the adhesion of zirconia core ceramics with their corresponding veneering ceramics, having different thermal expansion coefficients (TECs), when zirconia ceramics were coloured at green stage. Zirconia blocks (N=240; 6 mm x 7 mm x 7 mm) were manufactured from two materials namely, ICE Zirconia (Group 1) and Prettau Zirconia (Group 2). In their green stage, they were randomly divided into two groups. Half of the specimens were coloured with colouring liquid (shade A2), Three different veneering ceramics with different TEC (ICE Ceramic, GC Initial Zr and IPS e.max Ceram) were fired on both coloured and non-coloured zirconia cores. Specimens of high noble alloys (Esteticor Plus) veneered with ceramic (VM 13) (n= 16) acted as the control group. Core-veneer interface of the specimens were subjected to shear force in the Universal Testing Machine (0.5 mm-min-1). Neither the zirconia core material (P=0.318) nor colouring (P=0.188) significantly affected the results (three-way analysis of variance, Tukey's test). But the results were significantly affected by the veneering ceramic (P=0.000). Control group exhibited significantly higher mean bond strength values (45.7__.8) MPa than all other tested groups ((27.1__.4.1)-(39.7__.4.7) and (27.4__.5.6)-(35.9___4.7) MPa with and without colouring, respectively) (P^0.001). While in zirconia-veneer test groups, predominantly mixed type of failures were observed with the veneering ceramic covering ~ 1/3 of the substrate surface, in the metal-ceramic group, veneering ceramic was left adhered 1/3 of the metal surface. Colouring zirconia did not impair adhesion of veneering ceramic, but veneering ceramic had a significant influence on the core-veneer adhesion. Metal-ceramic adhesion was more reliable than all zirconia-veneer ceramics tested.展开更多
The size mismatch in an end-to-end vascular anastomosis between the host vessel and the graft may cause flow disturbance and predispose to thrombosis [1].Although a number of techniques have been employed to reduce th...The size mismatch in an end-to-end vascular anastomosis between the host vessel and the graft may cause flow disturbance and predispose to thrombosis [1].Although a number of techniques have been employed to reduce the risk of anastomotic thrombosis due to the size mismatch。展开更多
Purpose–In response to the problem of insufficient traction/braking adhesion force caused by the existence of the third-body medium on the rail surface,this study aims to analyze the utilization of wheel-rail adhesio...Purpose–In response to the problem of insufficient traction/braking adhesion force caused by the existence of the third-body medium on the rail surface,this study aims to analyze the utilization of wheel-rail adhesion coefficient under different medium conditions and propose relevant measures for reasonable and optimized utilization of adhesion to ensure the traction/braking performance and operation safety of trains.Design/methodology/approach–Based on the PLS-160 wheel-rail adhesion simulation test rig,the study investigates the variation patterns of maximum utilized adhesion characteristics on the rail surface under different conditions of small creepage and large slip.Through statistical analysis of multiple sets of experimental data,the statistical distribution patterns of maximum utilized adhesion on the rail surface are obtained,and a method for analyzing wheel-rail adhesion redundancy based on normal distribution is proposed.The study analyzes the utilization of traction/braking adhesion,as well as adhesion redundancy,for different medium under small creepage and large slip conditions.Based on these findings,relevant measures for the reasonable and optimized utilization of adhesion are derived.Findings–When the third-body medium exists on the rail surface,the train should adopt the low-level service braking to avoid the braking skidding by extending the braking distance.Compared with the current adhesion control strategy of small creepage,adopting appropriate strategies to control the train’s adhesion coefficient near the second peak point of the adhesion coefficient-slip ratio curve in large slip can effectively improve the traction/braking adhesion redundancy and the upper limit of adhesion utilization,thereby ensuring the traction/braking performance and operation safety of the train.Originality/value–Most existing studies focus on the wheel-rail adhesion coefficient values and variation patterns under different medium conditions,without considering whether the rail surface with different medium can provide sufficient traction/braking utilized adhesion coefficient for the train.Therefore,there is a risk of traction overspeeding/braking skidding.This study analyzes whether the rail surface with different medium can provide sufficient traction/braking utilized adhesion coefficient for the train and whether there is redundancy.Based on these findings,relevant measures for the reasonable and optimized utilization of adhesion are derived to further ensure operation safety of the train.展开更多
BACKGROUND Stem cells are undifferentiated cells that possess the potential for self-renewal with the capacity to differentiate into multiple lineages.In humans,their limited numbers pose a challenge in fulfilling the...BACKGROUND Stem cells are undifferentiated cells that possess the potential for self-renewal with the capacity to differentiate into multiple lineages.In humans,their limited numbers pose a challenge in fulfilling the necessary demands for the regeneration and repair of damaged tissues or organs.Studies suggested that mesenchymal stem cells(MSCs),necessary for repair and regeneration via transplantation,require doses ranging from 10 to 400 million cells.Furthermore,the limited expansion of MSCs restricts their therapeutic application.AIM To optimize a novel protocol to achieve qualitative and quantitative expansion of MSCs to reach the targeted number of cells for cellular transplantation and minimize the limitations in stem cell therapy protocols.METHODS Human umbilical cord(hUC)tissue derived MSCs were obtained and re-cultured.These cultured cells were subjected to the following evaluation pro-cedures:Immunophenotyping,immunocytochemical staining,trilineage differentiation,population doubling time and number,gene expression markers for proliferation,cell cycle progression,senescence-associatedβ-galactosidase assay,human telomerase reverse transcriptase(hTERT)expression,mycoplasma,cytomegalovirus and endotoxin detection.RESULTS Analysis of pluripotent gene markers Oct4,Sox2,and Nanog in recultured hUC-MSC revealed no significant differences.The immunophenotypic markers CD90,CD73,CD105,CD44,vimentin,CD29,Stro-1,and Lin28 were positively expressed by these recultured expanded MSCs,and were found negative for CD34,CD11b,CD19,CD45,and HLA-DR.The recultured hUC-MSC population continued to expand through passage 15.Proliferative gene expression of Pax6,BMP2,and TGFb1 showed no significant variation between recultured hUC-MSC groups.Nevertheless,a significant increase(P<0.001)in the mitotic phase of the cell cycle was observed in recultured hUC-MSCs.Cellular senescence markers(hTERT expression andβ-galactosidase activity)did not show any negative effect on recultured hUC-MSCs.Additionally,quality control assessments consistently confirmed the absence of mycoplasma,cytomegalovirus,and endotoxin contamination.CONCLUSION This study proposes the development of a novel protocol for efficiently expanding stem cell population.This would address the growing demand for larger stem cell doses needed for cellular transplantation and will significantly improve the feasibility of stem cell based therapies.展开更多
The expansion of a thick-walled hollow cylinder in soil is of non-self-similar nature that the stress/deformation paths are not the same for different soil material points.As a result,this problem cannot be solved by ...The expansion of a thick-walled hollow cylinder in soil is of non-self-similar nature that the stress/deformation paths are not the same for different soil material points.As a result,this problem cannot be solved by the common self-similar-based similarity techniques.This paper proposes a novel,exact solution for rigorous drained expansion analysis of a hollow cylinder of critical state soils.Considering stress-dependent elastic moduli of soils,new analytical stress and displacement solutions for the nonself-similar problem are developed taking the small strain assumption in the elastic zone.In the plastic zone,the cavity expansion response is formulated into a set of first-order partial differential equations(PDEs)with the combination use of Eulerian and Lagrangian descriptions,and a novel solution algorithm is developed to efficiently solve this complex boundary value problem.The solution is presented in a general form and thus can be useful for a wide range of soils.With the new solution,the non-self-similar nature induced by the finite outer boundary is clearly demonstrated and highlighted,which is found to be greatly different to the behaviour of cavity expansion in infinite soil mass.The present solution may serve as a benchmark for verifying the performance of advanced numerical techniques with critical state soil models and be used to capture the finite boundary effect for pressuremeter tests in small-sized calibration chambers.展开更多
Numerous engineering cases have demonstrated that the expansive soil channel slope remains susceptible to damage with the implementation of a rigid or closed protective structure. It is common for the protective struc...Numerous engineering cases have demonstrated that the expansive soil channel slope remains susceptible to damage with the implementation of a rigid or closed protective structure. It is common for the protective structure to experience bulging failure due to excessive swelling pressure. To investigate the swelling pressure properties of expansive soil, the constant volume test was employed to study the influence of water content and reserved expansion deformation on the characteristics of swelling pressure in strong expansive soils, and also to explore the evolution mechanism of the swelling pressure. The findings demonstrate that the swelling pressure-time curve can be classified into swelling pressure-time softening and swelling pressure-time stability type. The swelling pressuretime curve of the specimen with low water content is the swelling pressure-time softening type, and the softening level will be weakened with increasing reserved expansion deformation. Besides, the maximum swelling pressure Psmax decreases with increasing water content and reserved expansion deformation, especially for expansion ratio η from 24% to 37%. The reserved deformation has little effect on reducing Psmax when it is beyond 7% of the expansion rate. The specimen with low water content has a more homogeneous structure due to the significant expansion-filling effect, and the fracture and reorganization of the aggregates in the specimens with low water content cause the swelling pressure-time softening behavior. In addition, the proposed swelling pressure-time curve prediction model has a good prediction on the test results. If necessary, a deformation space of about 7% expansion rate is recommended to be reserved in the engineering to reduce the swelling pressure except for keeping a stable water content.展开更多
Lignin is the most abundant aromatic natural polymer,and receiving great attention in replacing various petro-leum-based polymers.The aim of this study is to investigate the feasibility of technical lignin as a polyol...Lignin is the most abundant aromatic natural polymer,and receiving great attention in replacing various petro-leum-based polymers.The aim of this study is to investigate the feasibility of technical lignin as a polyol for the synthesis of non-isocyanate polyurethane(NIPU)adhesives to substitute current polyurethane(PU)adhesives that have been synthesized with toxic isocyanate and polyols.Crude hardwood kraft lignin(C-HKL)was extracted from black liquor from a pulp mill followed by acetone fractionation to obtain acetone soluble-HKL(AS-HKL).Then,C-HKL,AS-HKL,and softwood sodium lignosulfonate(LS)were used for the synthesis of technical lignin-based NIPU adhesives through carbonation and polyamination and silane as a cross-linker.Their adhesion per-formance was determined for plywood.FTIR spectra showed the formation of urethane bonds and the reaction between lignin and silane.The NIPU adhesives prepared with C-HKL showed the highest adhesion strength among the three lignin-based NIPU adhesives.As the silane addition level increased,the adhesion strength of NIPU adhesives increased whereas formaldehyde emission decreased for all NIPU adhesives prepared.These results indicate that NIPU adhesives based on technical kraft lignin have a great potential as polyol for the synth-esis of bio-based NIPU adhesives for wood bonding.展开更多
Understanding the hydrate adhesion is important to tackling hydrate accretion in petro-pipelines.Herein,the relationship between the Tetrahydrofuran(THF)hydrate adhesion strength(AS)and surface stiffness on elastic co...Understanding the hydrate adhesion is important to tackling hydrate accretion in petro-pipelines.Herein,the relationship between the Tetrahydrofuran(THF)hydrate adhesion strength(AS)and surface stiffness on elastic coatings is systemically examined by experimental shear force measurements and theoretical methods.The mechanical factor-elastic modulus of the coatings greatly dictates the hydrate AS,which is explained by the adhesion mechanics theory,beyond the usual factors such as wettability and structural roughness.Moreover,the hydrate AS increases with reducing the thickness of the elastic coatings,resulted from the decrease of the apparent surface elastic modulus.The effect of critical thickness for the elastic materials with variable elastic modulus on the hydrate AS is also revealed.This study provides deep perspectives on the regulation of the hydrate AS by the elastic modulus of elastic materials,which is of significance to design anti-hydrate surfaces for mitigation of hydrate accretion in petro-pipelines.展开更多
Oxalate is an organic dicarboxylic acid that is a common component of plant foods.The kidneys are essential organs for oxalate excretion,but excessive oxalates may induce kidney stones.Jupiter microtubule associated h...Oxalate is an organic dicarboxylic acid that is a common component of plant foods.The kidneys are essential organs for oxalate excretion,but excessive oxalates may induce kidney stones.Jupiter microtubule associated homolog 2(JPT2)is a critical molecule in Ca^(2+)mobilization,and its intrinsic mechanism in oxalate exposure and kidney stones remains unclear.This study aimed to reveal the mechanism of JPT2 in oxalate exposure and kidney stones.Genetic approaches were used to control JPT2 expression in cells and mice,and the JPT2 mechanism of action was analyzed using transcriptomics and untargeted metabolomics.The results showed that oxalate exposure triggered the upregulation of JPT2,which is involved in nicotinic acid adenine dinucleotide phosphate(NAADP)-mediated Ca^(2+)mobilization.Transcriptomic analysis revealed that cell adhesion and macrophage inflammatory polarization were inhibited by JPT2 knockdown,and these were dominated by phosphatidylinositol 3-kinase(PI3K)/AKT signaling,respectively.Untargeted metabolomics indicated that JPT2 knockdown inhibited the production of succinic acid semialdehyde(SSA)in macrophages.Furthermore,JPT2 deficiency in mice inhibited kidney stones mineralization.In conclusion,this study demonstrates that oxalate exposure facilitates kidney stones by promoting crystal-cell adhesion,and modulating macrophage metabolism and inflammatory polarization via JPT2/PI3K/AKT signaling.展开更多
In recent years, lakes on the Qinghai-Tibet Plateau have become more responsive to climate change. In September 2011, Zonag Lake in Hoh Xil experienced sudden drainage, the water eventually flowed into Yanhu Lake, whi...In recent years, lakes on the Qinghai-Tibet Plateau have become more responsive to climate change. In September 2011, Zonag Lake in Hoh Xil experienced sudden drainage, the water eventually flowed into Yanhu Lake, which caused Yanhu Lake to continue to expand. The potential collapse of Yanhu Lake could directly threaten the operational safety of the adjacent Qinghai-Tibet Highway, Qinghai-Tibet Railway. To explore the implications of expanding lakes on the surrounding permafrost, we selected Hoh Xil Yanhu Lake on the Qinghai-Tibet Plateau to study the effect of lake expansion on permafrost degradation. The permafrost degradation in the Yanhu Lake basin from October 2017 to December 2022 was inverted using Sentinel-1 satellite image data and small baseline subset interferometry synthetic aperture radar(SBAS-In SAR) technology. Additionally, permafrost degradation from February 2007 and February 2010 was analyzed using advanced land observing satellite phased array-type L-band synthetic aperture radar(ALOS PALSAR) satellite images and differential interferometric synthetic aperture radar(D-In SAR) technique. The results showed that the permafrost around Yanhu Lake experienced accelerated degradation. Prior to the expansion of Yanhu Lake, the average annual deformation rate along the line of sight(LOS) direction was 6.7 mm/yr. After the expansion, the rate increased to 20.9 mm/yr. The integration of spatial-temporal distribution maps of surface subsidence, Wudaoliang borehole geothermal data, meteorological data, Yanhu Lake surface area changes, and water level changes supports the assertion that the intensified permafrost degradation could be attributed to lake expansion rather than the rising air temperature. Furthermore, permafrost degradation around Yanhu Lake could impact vital infrastructure such as the adjacent Qinghai-Tibet Highway and Qinghai-Tibet Railway.展开更多
Multiple myeloma(MM)is a hematologic malignancy notorious for its high relapse rate and development of drug resistance,in which cell adhesion-mediated drug resistance plays a critical role.This study integrated four R...Multiple myeloma(MM)is a hematologic malignancy notorious for its high relapse rate and development of drug resistance,in which cell adhesion-mediated drug resistance plays a critical role.This study integrated four RNA sequencing datasets(CoMMpass,GSE136337,GSE9782,and GSE2658)and focused on analyzing 1706 adhesionrelated genes.Rigorous univariate Cox regression analysis identified 18 key prognosis-related genes,including KIF14,TROAP,FLNA,MSN,LGALS1,PECAM1,and ALCAM,which demonstrated the strongest associations with poor overall survival(OS)in MM patients.To comprehensively evaluate the impact of cell adhesion on MM prognosis,an adhesion-related risk score(ARRS)model was constructed using Lasso Cox regression analysis.The ARRS model emerged as an independent prognostic factor for predicting OS.Furthermore,our findings revealed that a heightened cell adhesion effect correlated with tumor resistance to DNA-damaging drugs,protein kinase inhibitors,and drugs targeting the PI3K/Akt/mTOR signaling pathway.Nevertheless,we identified promising drug candidates,such as tirofiban,pirenzepine,erlotinib,and bosutinib,which exhibit potential in reversing this resistance.In vitro,experiments employing NCIH929,RPMI8226,and AMO1 cell lines confirmed that MM cell lines with high ARRS exhibited poor sensitivity to the aforementioned candidate drugs.By employing siRNA-mediated knockdown of the key ARRS model gene KIF14,we observed suppressed proliferation of NCIH929 cells,along with decreased adhesion to BMSCs and fibronectin.This study presents compelling evidence establishing cell adhesion as a significant prognostic factor in MM.Additionally,potential molecular mechanisms underlying adhesion-related resistance are proposed,along with viable strategies to overcome such resistance.These findings provide a solid scientific foundation for facilitating clinically stratified treatment of MM.展开更多
Solid-state zinc-ion capacitors are emerging as promising candidates for large-scale energy storage owing to improved safety,mechanical and thermal stability and easy-to-direct stacking.Hydrogel electrolytes are appea...Solid-state zinc-ion capacitors are emerging as promising candidates for large-scale energy storage owing to improved safety,mechanical and thermal stability and easy-to-direct stacking.Hydrogel electrolytes are appealing solid-state electrolytes because of eco-friendliness,high conductivity and intrinsic flexibility.However,the electrolyte/electrode interfacial contact and anti-freezing properties of current hydrogel electrolytes are still challenging for practical applications of zinc-ion capacitors.Here,we report a class of hydrogel electrolytes that couple high interfacial adhesion and anti-freezing performance.The synergy of tough hydrogel matrix and chemical anchorage enables a well-adhered interface between hydrogel electrolyte and electrode.Meanwhile,the cooperative solvation of ZnCl2 and LiCl hybrid salts renders the hydrogel electrolyte high ionic conductivity and mechanical elasticity simultaneously at low temperatures.More significantly,the Zn||carbon nanotubes hybrid capacitor based on this hydrogel electrolyte exhibits low-temperature capacitive performance,delivering high-energy density of 39 Wh kg^(-1)at-60°C with capacity retention of 98.7%over 10,000 cycles.With the benefits of the well-adhered electrolyte/electrode interface and the anti-freezing hydrogel electrolyte,the Zn/Li hybrid capacitor is able to accommodate dynamic deformations and function well under 1000 tension cycles even at-60°C.This work provides a powerful strategy for enabling stable operation of low-temperature zinc-ion capacitors.展开更多
Experimental scratch tests and first-principles calculations were used to investigate the adhesion property of AlCrNbSiTi high-entropy alloy(HEA)coatings on zirconium substrates.AlCrNbSiTi HEA and Cr coatings were dep...Experimental scratch tests and first-principles calculations were used to investigate the adhesion property of AlCrNbSiTi high-entropy alloy(HEA)coatings on zirconium substrates.AlCrNbSiTi HEA and Cr coatings were deposited on Zr alloy substrates using multi-arc ion plating technology,and scratch tests were subsequently conducted to estimate the adhesion property of the coatings.The results indicated that Cr coatings had better adhesion strength than HEA coatings,and the HEA coatings showed brittleness.The special quasi-random structure approach was used to build HEA models,and Cr/Zr and HEA/Zr interface models were employed to investigate the cohesion between the coatings and Zr substrate using first-principles calculations.The calculated interface energies showed that the cohesion between the Cr coating and the Zr substrate was stronger than that of the HEA coating with Zr.In contrary to Al or Si in the HEA coating,Cr,Nb,and Ti atoms binded strongly with Zr substrate.Based on the calculated elastic constants,it was found that low Cr and high Al content decreased the mechanical performances of HEA coatings.Finally,this study demonstrated the utilization of a combined approach involving first-principles calculations and experimental studies for future HEA coating development.展开更多
The expansion chamber serves as the primary silencing structure within the exhaust pipeline.However,it can also act as a sound-emitting structure when subjected to airflow.This article presents a hybrid method for num...The expansion chamber serves as the primary silencing structure within the exhaust pipeline.However,it can also act as a sound-emitting structure when subjected to airflow.This article presents a hybrid method for numerically simulating and analyzing the unsteady flow and aerodynamic noise in an expansion chamber under the influence of airflow.A fluid simulation model is established,utilizing the Large Eddy Simulation(LES)method to calculate the unsteady flow within the expansion chamber.The simulation results effectively capture the development and changes of the unsteady flow and vorticity inside the cavity,exhibiting a high level of consistency with experimental observations.To calculate the aerodynamic noise sources within the cavity,the flow field results are integrated using the method of integral interpolation and inserted into the acoustic grid.The acoustic analogy method is then employed to determine the aerodynamic noise sources.An acoustic simulation model is established,and the flow noise source is imported into the sound field grid to calculate the sound pressure at the far-field response point.The calculated sound pressure levels and resonance frequencies show good agreement with the experimental results.To address the issue of airflow regeneration noise within the cavity,perforated tubes are selected as a means of noise suppression.An experimental platformfor airflow regeneration noise is constructed,and experimental samples are processed to analyze and verify the noise suppression effect of perforated tube expansion cavities under different airflow velocities.The research findings indicate that the perforated tube expansion cavity can effectively suppress low-frequency aerodynamic noise within the cavity by impeding the formation of strong shear layers.Moreover,the semi-perforated tube expansion cavity demonstrates the most effective suppression of aerodynamic noise.展开更多
With the increasing penetration of wind and solar energies,the accompanying uncertainty that propagates in the system places higher requirements on the expansion planning of power systems.A source-grid-load-storage co...With the increasing penetration of wind and solar energies,the accompanying uncertainty that propagates in the system places higher requirements on the expansion planning of power systems.A source-grid-load-storage coordinated expansion planning model based on stochastic programming was proposed to suppress the impact of wind and solar energy fluctuations.Multiple types of system components,including demand response service entities,converter stations,DC transmission systems,cascade hydropower stations,and other traditional components,have been extensively modeled.Moreover,energy storage systems are considered to improve the accommodation level of renewable energy and alleviate the influence of intermittence.Demand-response service entities from the load side are used to reduce and move the demand during peak load periods.The uncertainties in wind,solar energy,and loads were simulated using stochastic programming.Finally,the effectiveness of the proposed model is verified through numerical simulations.展开更多
A novel negative thermal expansion(NTE) material NdMnO_(3) was synthesized by solid-state method at 1 523 K. The crystal structure, phase transition, pores effect and negative expansion properties of NdMnO_(3) were in...A novel negative thermal expansion(NTE) material NdMnO_(3) was synthesized by solid-state method at 1 523 K. The crystal structure, phase transition, pores effect and negative expansion properties of NdMnO_(3) were investigated by variable temperature X-ray diffraction(XRD), scanning electron microscope(SEM) and variable temperature Raman spectra. The compound exhibits NTE properties in the orderly O' phase crystal structure. When the temperature is from 293 to 759 K, the ceramic NdMnO_(3) shows negative thermal expansion of-4.7×10^(-6)/K. As temperature increases, the ceramic NdMnO_(3) presents NTE property range from 759 to 1 007 K. The average linear expansion coefficient is-18.88×10^(-6)/K. The physical mechanism of NTE is discussed and clarified through experiments.展开更多
In the context of global mean square error concerning the number of random variables in the representation,the Karhunen–Loève(KL)expansion is the optimal series expansion method for random field discretization.T...In the context of global mean square error concerning the number of random variables in the representation,the Karhunen–Loève(KL)expansion is the optimal series expansion method for random field discretization.The computational efficiency and accuracy of the KL expansion are contingent upon the accurate resolution of the Fredholm integral eigenvalue problem(IEVP).The paper proposes an interpolation method based on different interpolation basis functions such as moving least squares(MLS),least squares(LS),and finite element method(FEM)to solve the IEVP.Compared with the Galerkin method based on finite element or Legendre polynomials,the main advantage of the interpolation method is that,in the calculation of eigenvalues and eigenfunctions in one-dimensional random fields,the integral matrix containing covariance function only requires a single integral,which is less than a two-folded integral by the Galerkin method.The effectiveness and computational efficiency of the proposed interpolation method are verified through various one-dimensional examples.Furthermore,based on theKL expansion and polynomial chaos expansion,the stochastic analysis of two-dimensional regular and irregular domains is conducted,and the basis function of the extended finite element method(XFEM)is introduced as the interpolation basis function in two-dimensional irregular domains to solve the IEVP.展开更多
The Mutis-Timau Forest Complex,located on Timor Island,Indonesia,is a mountainous tropical forest area that gradually decreases due to deforestation and forest degradation.Previous modelling studies based on patterns ...The Mutis-Timau Forest Complex,located on Timor Island,Indonesia,is a mountainous tropical forest area that gradually decreases due to deforestation and forest degradation.Previous modelling studies based on patterns indicate that deforestation primarily occurs at lower elevations and near the boundaries of forests and settlements,often associated with shifting cultivation by local farmers.This study adopts a process-based modelling approach,specifically the agent-based model,to simulate land changes,particularly farmers'expansion of agricultural land around the Mutis mountain forest.The underlying concept of this agent-based approach is the interaction between the human and environmental systems.Farmers,representing the human system,interact with the land,which represents the environmental system,through land use decision-making mechanisms.The research was conducted in the Community Forest of the Timor Tengah Utara District,one of the sites within the Mutis-Timau Forest Complex with the highest deforestation rate.Land use change simulations were performed using agent-based modelling from 1999 to 2030,considering the socio-economic conditions of farmers,spatial preferences,land use decisions,and natural transitions.The results revealed that the agricultural area increased by 14%under the Business as Usual scenario and 5%under the Reducing Emission from Deforestation and Forest Degradation scenario,compared to the initial agricultural area of 245 hectares.The probability of farmers deciding to extend agricultural activities was positively associated with the number of livestock maintained by farmers and the size of the village area.Conversely,the likelihood of farmers opting for agricultural extensification decreased with an increase in the area of private land and the farmer's age.These findings are crucial for the managers of the Mutis-Timau Forest Complex and other relevant stakeholders,as they aid in arranging actions to combat deforestation,designing proper forest-related policies,and providing support for initiatives such as reducing emissions from deforestation and forest degradation programs or further incentive schemes.展开更多
In response to the ongoing energy crisis,advancing the field of electrocatalytic water splitting is of utmost significance,necessitating the urgent development of high-performance,cost-effective,and durable hydrogen e...In response to the ongoing energy crisis,advancing the field of electrocatalytic water splitting is of utmost significance,necessitating the urgent development of high-performance,cost-effective,and durable hydrogen evolution reaction catalysts.But the generated gas bubble adherence to the electrode surface and sluggish separation contribute to significant energy loss,primarily due to the insufficient exposure of active sites,thus substantially hindering electrochemical performance.Here,we successfully developed a superaerophobic catalytic electrode by loading phosphorus-doped nickel metal(NiP_(x))onto various conductive substrates via an electrodeposition method.The electrode exhibits a unique surface structure,characterized by prominent surface fissures,which not only exposes additional active sites but also endows the electrode with superaerophobic properties.The NiP_(x)/Ti electrode demonstrates superior electrocatalytic activity for hydrogen evolution reaction,significantly outperforming a platinum plate,displaying an overpotential of mere 216 mV to achieve a current density of-500 mA cm^(-2) in 1 M KOH.Furthermore,the NiP_(x)/Ti electrode manifests outstanding durability and robustness during continuous electrolysis,maintaining stability at a current density of-10 mA cm^(-2) over a duration of 2000 h.Owing to the straightforward and scalable preparation methods,this highly efficient and stable NiP_(x)/Ti electrocatalyst offers a novel strategy for the development of industrial water electrolysis.展开更多
文摘This study evaluated the adhesion of zirconia core ceramics with their corresponding veneering ceramics, having different thermal expansion coefficients (TECs), when zirconia ceramics were coloured at green stage. Zirconia blocks (N=240; 6 mm x 7 mm x 7 mm) were manufactured from two materials namely, ICE Zirconia (Group 1) and Prettau Zirconia (Group 2). In their green stage, they were randomly divided into two groups. Half of the specimens were coloured with colouring liquid (shade A2), Three different veneering ceramics with different TEC (ICE Ceramic, GC Initial Zr and IPS e.max Ceram) were fired on both coloured and non-coloured zirconia cores. Specimens of high noble alloys (Esteticor Plus) veneered with ceramic (VM 13) (n= 16) acted as the control group. Core-veneer interface of the specimens were subjected to shear force in the Universal Testing Machine (0.5 mm-min-1). Neither the zirconia core material (P=0.318) nor colouring (P=0.188) significantly affected the results (three-way analysis of variance, Tukey's test). But the results were significantly affected by the veneering ceramic (P=0.000). Control group exhibited significantly higher mean bond strength values (45.7__.8) MPa than all other tested groups ((27.1__.4.1)-(39.7__.4.7) and (27.4__.5.6)-(35.9___4.7) MPa with and without colouring, respectively) (P^0.001). While in zirconia-veneer test groups, predominantly mixed type of failures were observed with the veneering ceramic covering ~ 1/3 of the substrate surface, in the metal-ceramic group, veneering ceramic was left adhered 1/3 of the metal surface. Colouring zirconia did not impair adhesion of veneering ceramic, but veneering ceramic had a significant influence on the core-veneer adhesion. Metal-ceramic adhesion was more reliable than all zirconia-veneer ceramics tested.
基金supported by Grants-in-Aid from the National Natural Science Foundation of China No.10632010,30670517
文摘The size mismatch in an end-to-end vascular anastomosis between the host vessel and the graft may cause flow disturbance and predispose to thrombosis [1].Although a number of techniques have been employed to reduce the risk of anastomotic thrombosis due to the size mismatch。
文摘Purpose–In response to the problem of insufficient traction/braking adhesion force caused by the existence of the third-body medium on the rail surface,this study aims to analyze the utilization of wheel-rail adhesion coefficient under different medium conditions and propose relevant measures for reasonable and optimized utilization of adhesion to ensure the traction/braking performance and operation safety of trains.Design/methodology/approach–Based on the PLS-160 wheel-rail adhesion simulation test rig,the study investigates the variation patterns of maximum utilized adhesion characteristics on the rail surface under different conditions of small creepage and large slip.Through statistical analysis of multiple sets of experimental data,the statistical distribution patterns of maximum utilized adhesion on the rail surface are obtained,and a method for analyzing wheel-rail adhesion redundancy based on normal distribution is proposed.The study analyzes the utilization of traction/braking adhesion,as well as adhesion redundancy,for different medium under small creepage and large slip conditions.Based on these findings,relevant measures for the reasonable and optimized utilization of adhesion are derived.Findings–When the third-body medium exists on the rail surface,the train should adopt the low-level service braking to avoid the braking skidding by extending the braking distance.Compared with the current adhesion control strategy of small creepage,adopting appropriate strategies to control the train’s adhesion coefficient near the second peak point of the adhesion coefficient-slip ratio curve in large slip can effectively improve the traction/braking adhesion redundancy and the upper limit of adhesion utilization,thereby ensuring the traction/braking performance and operation safety of the train.Originality/value–Most existing studies focus on the wheel-rail adhesion coefficient values and variation patterns under different medium conditions,without considering whether the rail surface with different medium can provide sufficient traction/braking utilized adhesion coefficient for the train.Therefore,there is a risk of traction overspeeding/braking skidding.This study analyzes whether the rail surface with different medium can provide sufficient traction/braking utilized adhesion coefficient for the train and whether there is redundancy.Based on these findings,relevant measures for the reasonable and optimized utilization of adhesion are derived to further ensure operation safety of the train.
基金Supported by Higher Education Commission,Islamabad,Pakistan grant,No.20-17590/NRPU/R&D/HEC/20212021.
文摘BACKGROUND Stem cells are undifferentiated cells that possess the potential for self-renewal with the capacity to differentiate into multiple lineages.In humans,their limited numbers pose a challenge in fulfilling the necessary demands for the regeneration and repair of damaged tissues or organs.Studies suggested that mesenchymal stem cells(MSCs),necessary for repair and regeneration via transplantation,require doses ranging from 10 to 400 million cells.Furthermore,the limited expansion of MSCs restricts their therapeutic application.AIM To optimize a novel protocol to achieve qualitative and quantitative expansion of MSCs to reach the targeted number of cells for cellular transplantation and minimize the limitations in stem cell therapy protocols.METHODS Human umbilical cord(hUC)tissue derived MSCs were obtained and re-cultured.These cultured cells were subjected to the following evaluation pro-cedures:Immunophenotyping,immunocytochemical staining,trilineage differentiation,population doubling time and number,gene expression markers for proliferation,cell cycle progression,senescence-associatedβ-galactosidase assay,human telomerase reverse transcriptase(hTERT)expression,mycoplasma,cytomegalovirus and endotoxin detection.RESULTS Analysis of pluripotent gene markers Oct4,Sox2,and Nanog in recultured hUC-MSC revealed no significant differences.The immunophenotypic markers CD90,CD73,CD105,CD44,vimentin,CD29,Stro-1,and Lin28 were positively expressed by these recultured expanded MSCs,and were found negative for CD34,CD11b,CD19,CD45,and HLA-DR.The recultured hUC-MSC population continued to expand through passage 15.Proliferative gene expression of Pax6,BMP2,and TGFb1 showed no significant variation between recultured hUC-MSC groups.Nevertheless,a significant increase(P<0.001)in the mitotic phase of the cell cycle was observed in recultured hUC-MSCs.Cellular senescence markers(hTERT expression andβ-galactosidase activity)did not show any negative effect on recultured hUC-MSCs.Additionally,quality control assessments consistently confirmed the absence of mycoplasma,cytomegalovirus,and endotoxin contamination.CONCLUSION This study proposes the development of a novel protocol for efficiently expanding stem cell population.This would address the growing demand for larger stem cell doses needed for cellular transplantation and will significantly improve the feasibility of stem cell based therapies.
基金funding support from the National Key Research and Development Program of China(Grant No.2023YFB2604004)the National Natural Science Foundation of China(Grant No.52108374)the“Taishan”Scholar Program of Shandong Province,China(Grant No.tsqn201909016)。
文摘The expansion of a thick-walled hollow cylinder in soil is of non-self-similar nature that the stress/deformation paths are not the same for different soil material points.As a result,this problem cannot be solved by the common self-similar-based similarity techniques.This paper proposes a novel,exact solution for rigorous drained expansion analysis of a hollow cylinder of critical state soils.Considering stress-dependent elastic moduli of soils,new analytical stress and displacement solutions for the nonself-similar problem are developed taking the small strain assumption in the elastic zone.In the plastic zone,the cavity expansion response is formulated into a set of first-order partial differential equations(PDEs)with the combination use of Eulerian and Lagrangian descriptions,and a novel solution algorithm is developed to efficiently solve this complex boundary value problem.The solution is presented in a general form and thus can be useful for a wide range of soils.With the new solution,the non-self-similar nature induced by the finite outer boundary is clearly demonstrated and highlighted,which is found to be greatly different to the behaviour of cavity expansion in infinite soil mass.The present solution may serve as a benchmark for verifying the performance of advanced numerical techniques with critical state soil models and be used to capture the finite boundary effect for pressuremeter tests in small-sized calibration chambers.
基金financially supported by the National Key R&D Program of China (Grant No. 2019YFC1509901)。
文摘Numerous engineering cases have demonstrated that the expansive soil channel slope remains susceptible to damage with the implementation of a rigid or closed protective structure. It is common for the protective structure to experience bulging failure due to excessive swelling pressure. To investigate the swelling pressure properties of expansive soil, the constant volume test was employed to study the influence of water content and reserved expansion deformation on the characteristics of swelling pressure in strong expansive soils, and also to explore the evolution mechanism of the swelling pressure. The findings demonstrate that the swelling pressure-time curve can be classified into swelling pressure-time softening and swelling pressure-time stability type. The swelling pressuretime curve of the specimen with low water content is the swelling pressure-time softening type, and the softening level will be weakened with increasing reserved expansion deformation. Besides, the maximum swelling pressure Psmax decreases with increasing water content and reserved expansion deformation, especially for expansion ratio η from 24% to 37%. The reserved deformation has little effect on reducing Psmax when it is beyond 7% of the expansion rate. The specimen with low water content has a more homogeneous structure due to the significant expansion-filling effect, and the fracture and reorganization of the aggregates in the specimens with low water content cause the swelling pressure-time softening behavior. In addition, the proposed swelling pressure-time curve prediction model has a good prediction on the test results. If necessary, a deformation space of about 7% expansion rate is recommended to be reserved in the engineering to reduce the swelling pressure except for keeping a stable water content.
基金supported by the National Research Foundation(NRF)of Korea,and funded by the Korean Government(MSIT)(Grant No.RS-2023-00240043).
文摘Lignin is the most abundant aromatic natural polymer,and receiving great attention in replacing various petro-leum-based polymers.The aim of this study is to investigate the feasibility of technical lignin as a polyol for the synthesis of non-isocyanate polyurethane(NIPU)adhesives to substitute current polyurethane(PU)adhesives that have been synthesized with toxic isocyanate and polyols.Crude hardwood kraft lignin(C-HKL)was extracted from black liquor from a pulp mill followed by acetone fractionation to obtain acetone soluble-HKL(AS-HKL).Then,C-HKL,AS-HKL,and softwood sodium lignosulfonate(LS)were used for the synthesis of technical lignin-based NIPU adhesives through carbonation and polyamination and silane as a cross-linker.Their adhesion per-formance was determined for plywood.FTIR spectra showed the formation of urethane bonds and the reaction between lignin and silane.The NIPU adhesives prepared with C-HKL showed the highest adhesion strength among the three lignin-based NIPU adhesives.As the silane addition level increased,the adhesion strength of NIPU adhesives increased whereas formaldehyde emission decreased for all NIPU adhesives prepared.These results indicate that NIPU adhesives based on technical kraft lignin have a great potential as polyol for the synth-esis of bio-based NIPU adhesives for wood bonding.
基金This work is financially supported by the Key Laboratory of Icing and Anti/De-icing of CARDC(Grant No.IADL20210402)the National Natural Science Foundation of China(Grant Nos.12002350,12172314,11772278 and 11904300)+1 种基金the Jiangxi Provincial Outstanding Young Talents Program(Grant No.20192BCBL23029)the Fundamental Research Funds for the Central Universities(Xiamen University:Grant No.20720210025).
文摘Understanding the hydrate adhesion is important to tackling hydrate accretion in petro-pipelines.Herein,the relationship between the Tetrahydrofuran(THF)hydrate adhesion strength(AS)and surface stiffness on elastic coatings is systemically examined by experimental shear force measurements and theoretical methods.The mechanical factor-elastic modulus of the coatings greatly dictates the hydrate AS,which is explained by the adhesion mechanics theory,beyond the usual factors such as wettability and structural roughness.Moreover,the hydrate AS increases with reducing the thickness of the elastic coatings,resulted from the decrease of the apparent surface elastic modulus.The effect of critical thickness for the elastic materials with variable elastic modulus on the hydrate AS is also revealed.This study provides deep perspectives on the regulation of the hydrate AS by the elastic modulus of elastic materials,which is of significance to design anti-hydrate surfaces for mitigation of hydrate accretion in petro-pipelines.
基金supported by the National Natural Science Foundation of China(Grant Nos.:82070723,82270797)Nature Science Foundation of Hubei Province,China(Grant No.:2022CFC020).
文摘Oxalate is an organic dicarboxylic acid that is a common component of plant foods.The kidneys are essential organs for oxalate excretion,but excessive oxalates may induce kidney stones.Jupiter microtubule associated homolog 2(JPT2)is a critical molecule in Ca^(2+)mobilization,and its intrinsic mechanism in oxalate exposure and kidney stones remains unclear.This study aimed to reveal the mechanism of JPT2 in oxalate exposure and kidney stones.Genetic approaches were used to control JPT2 expression in cells and mice,and the JPT2 mechanism of action was analyzed using transcriptomics and untargeted metabolomics.The results showed that oxalate exposure triggered the upregulation of JPT2,which is involved in nicotinic acid adenine dinucleotide phosphate(NAADP)-mediated Ca^(2+)mobilization.Transcriptomic analysis revealed that cell adhesion and macrophage inflammatory polarization were inhibited by JPT2 knockdown,and these were dominated by phosphatidylinositol 3-kinase(PI3K)/AKT signaling,respectively.Untargeted metabolomics indicated that JPT2 knockdown inhibited the production of succinic acid semialdehyde(SSA)in macrophages.Furthermore,JPT2 deficiency in mice inhibited kidney stones mineralization.In conclusion,this study demonstrates that oxalate exposure facilitates kidney stones by promoting crystal-cell adhesion,and modulating macrophage metabolism and inflammatory polarization via JPT2/PI3K/AKT signaling.
基金supported by the Natural Science Foundation of Qinghai Province, China (No.2021-ZJ940Q)。
文摘In recent years, lakes on the Qinghai-Tibet Plateau have become more responsive to climate change. In September 2011, Zonag Lake in Hoh Xil experienced sudden drainage, the water eventually flowed into Yanhu Lake, which caused Yanhu Lake to continue to expand. The potential collapse of Yanhu Lake could directly threaten the operational safety of the adjacent Qinghai-Tibet Highway, Qinghai-Tibet Railway. To explore the implications of expanding lakes on the surrounding permafrost, we selected Hoh Xil Yanhu Lake on the Qinghai-Tibet Plateau to study the effect of lake expansion on permafrost degradation. The permafrost degradation in the Yanhu Lake basin from October 2017 to December 2022 was inverted using Sentinel-1 satellite image data and small baseline subset interferometry synthetic aperture radar(SBAS-In SAR) technology. Additionally, permafrost degradation from February 2007 and February 2010 was analyzed using advanced land observing satellite phased array-type L-band synthetic aperture radar(ALOS PALSAR) satellite images and differential interferometric synthetic aperture radar(D-In SAR) technique. The results showed that the permafrost around Yanhu Lake experienced accelerated degradation. Prior to the expansion of Yanhu Lake, the average annual deformation rate along the line of sight(LOS) direction was 6.7 mm/yr. After the expansion, the rate increased to 20.9 mm/yr. The integration of spatial-temporal distribution maps of surface subsidence, Wudaoliang borehole geothermal data, meteorological data, Yanhu Lake surface area changes, and water level changes supports the assertion that the intensified permafrost degradation could be attributed to lake expansion rather than the rising air temperature. Furthermore, permafrost degradation around Yanhu Lake could impact vital infrastructure such as the adjacent Qinghai-Tibet Highway and Qinghai-Tibet Railway.
基金supported by Incubation Program for Clinical Trials(No.19HXFH030)Achievement Transformation Project(No.CGZH21001)+4 种基金1.3.5 Project for Disciplines of Excellence,West China Hospital,Sichuan University(No.ZYJC21007)Translational Research Grant of NCRCH(No.2021WWB03),Chengdu Science and Technology Program(No.2022-YF05-01444-SN)Key Research and Development Program of Sichuan Province(No.2023YFS0031)Post-Doctor Research Project,West China Hospital,Sichuan University(No.2023HXBH111)National Key Research and Development Program of China(Nos.2022YFC2502600,2022YFC2502603).
文摘Multiple myeloma(MM)is a hematologic malignancy notorious for its high relapse rate and development of drug resistance,in which cell adhesion-mediated drug resistance plays a critical role.This study integrated four RNA sequencing datasets(CoMMpass,GSE136337,GSE9782,and GSE2658)and focused on analyzing 1706 adhesionrelated genes.Rigorous univariate Cox regression analysis identified 18 key prognosis-related genes,including KIF14,TROAP,FLNA,MSN,LGALS1,PECAM1,and ALCAM,which demonstrated the strongest associations with poor overall survival(OS)in MM patients.To comprehensively evaluate the impact of cell adhesion on MM prognosis,an adhesion-related risk score(ARRS)model was constructed using Lasso Cox regression analysis.The ARRS model emerged as an independent prognostic factor for predicting OS.Furthermore,our findings revealed that a heightened cell adhesion effect correlated with tumor resistance to DNA-damaging drugs,protein kinase inhibitors,and drugs targeting the PI3K/Akt/mTOR signaling pathway.Nevertheless,we identified promising drug candidates,such as tirofiban,pirenzepine,erlotinib,and bosutinib,which exhibit potential in reversing this resistance.In vitro,experiments employing NCIH929,RPMI8226,and AMO1 cell lines confirmed that MM cell lines with high ARRS exhibited poor sensitivity to the aforementioned candidate drugs.By employing siRNA-mediated knockdown of the key ARRS model gene KIF14,we observed suppressed proliferation of NCIH929 cells,along with decreased adhesion to BMSCs and fibronectin.This study presents compelling evidence establishing cell adhesion as a significant prognostic factor in MM.Additionally,potential molecular mechanisms underlying adhesion-related resistance are proposed,along with viable strategies to overcome such resistance.These findings provide a solid scientific foundation for facilitating clinically stratified treatment of MM.
基金This work was supported by the Natural Science Foundation of Jiangsu Province(BK20220213)the Fundamental Research Funds of Jiangsu Key Laboratory of Biomass Energy and Material(JSBEM-S-202210 and JSBEM-S-202102).
文摘Solid-state zinc-ion capacitors are emerging as promising candidates for large-scale energy storage owing to improved safety,mechanical and thermal stability and easy-to-direct stacking.Hydrogel electrolytes are appealing solid-state electrolytes because of eco-friendliness,high conductivity and intrinsic flexibility.However,the electrolyte/electrode interfacial contact and anti-freezing properties of current hydrogel electrolytes are still challenging for practical applications of zinc-ion capacitors.Here,we report a class of hydrogel electrolytes that couple high interfacial adhesion and anti-freezing performance.The synergy of tough hydrogel matrix and chemical anchorage enables a well-adhered interface between hydrogel electrolyte and electrode.Meanwhile,the cooperative solvation of ZnCl2 and LiCl hybrid salts renders the hydrogel electrolyte high ionic conductivity and mechanical elasticity simultaneously at low temperatures.More significantly,the Zn||carbon nanotubes hybrid capacitor based on this hydrogel electrolyte exhibits low-temperature capacitive performance,delivering high-energy density of 39 Wh kg^(-1)at-60°C with capacity retention of 98.7%over 10,000 cycles.With the benefits of the well-adhered electrolyte/electrode interface and the anti-freezing hydrogel electrolyte,the Zn/Li hybrid capacitor is able to accommodate dynamic deformations and function well under 1000 tension cycles even at-60°C.This work provides a powerful strategy for enabling stable operation of low-temperature zinc-ion capacitors.
基金supported by Stability Supports Research Project of Treasury Department(No.197801)Talent Fund of CIAE(No.219213)。
文摘Experimental scratch tests and first-principles calculations were used to investigate the adhesion property of AlCrNbSiTi high-entropy alloy(HEA)coatings on zirconium substrates.AlCrNbSiTi HEA and Cr coatings were deposited on Zr alloy substrates using multi-arc ion plating technology,and scratch tests were subsequently conducted to estimate the adhesion property of the coatings.The results indicated that Cr coatings had better adhesion strength than HEA coatings,and the HEA coatings showed brittleness.The special quasi-random structure approach was used to build HEA models,and Cr/Zr and HEA/Zr interface models were employed to investigate the cohesion between the coatings and Zr substrate using first-principles calculations.The calculated interface energies showed that the cohesion between the Cr coating and the Zr substrate was stronger than that of the HEA coating with Zr.In contrary to Al or Si in the HEA coating,Cr,Nb,and Ti atoms binded strongly with Zr substrate.Based on the calculated elastic constants,it was found that low Cr and high Al content decreased the mechanical performances of HEA coatings.Finally,this study demonstrated the utilization of a combined approach involving first-principles calculations and experimental studies for future HEA coating development.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.12104153 and 51765017)China Postdoctoral Science Foundation(Grant No.2021M701963)Training Plan for Academic and Technical Leaders of Major Disciplines in Jiangxi Province,China(Grant No.20204BCJL23034).
文摘The expansion chamber serves as the primary silencing structure within the exhaust pipeline.However,it can also act as a sound-emitting structure when subjected to airflow.This article presents a hybrid method for numerically simulating and analyzing the unsteady flow and aerodynamic noise in an expansion chamber under the influence of airflow.A fluid simulation model is established,utilizing the Large Eddy Simulation(LES)method to calculate the unsteady flow within the expansion chamber.The simulation results effectively capture the development and changes of the unsteady flow and vorticity inside the cavity,exhibiting a high level of consistency with experimental observations.To calculate the aerodynamic noise sources within the cavity,the flow field results are integrated using the method of integral interpolation and inserted into the acoustic grid.The acoustic analogy method is then employed to determine the aerodynamic noise sources.An acoustic simulation model is established,and the flow noise source is imported into the sound field grid to calculate the sound pressure at the far-field response point.The calculated sound pressure levels and resonance frequencies show good agreement with the experimental results.To address the issue of airflow regeneration noise within the cavity,perforated tubes are selected as a means of noise suppression.An experimental platformfor airflow regeneration noise is constructed,and experimental samples are processed to analyze and verify the noise suppression effect of perforated tube expansion cavities under different airflow velocities.The research findings indicate that the perforated tube expansion cavity can effectively suppress low-frequency aerodynamic noise within the cavity by impeding the formation of strong shear layers.Moreover,the semi-perforated tube expansion cavity demonstrates the most effective suppression of aerodynamic noise.
基金supported by Science and Technology Project of SGCC(SGSW0000FZGHBJS2200070)。
文摘With the increasing penetration of wind and solar energies,the accompanying uncertainty that propagates in the system places higher requirements on the expansion planning of power systems.A source-grid-load-storage coordinated expansion planning model based on stochastic programming was proposed to suppress the impact of wind and solar energy fluctuations.Multiple types of system components,including demand response service entities,converter stations,DC transmission systems,cascade hydropower stations,and other traditional components,have been extensively modeled.Moreover,energy storage systems are considered to improve the accommodation level of renewable energy and alleviate the influence of intermittence.Demand-response service entities from the load side are used to reduce and move the demand during peak load periods.The uncertainties in wind,solar energy,and loads were simulated using stochastic programming.Finally,the effectiveness of the proposed model is verified through numerical simulations.
文摘A novel negative thermal expansion(NTE) material NdMnO_(3) was synthesized by solid-state method at 1 523 K. The crystal structure, phase transition, pores effect and negative expansion properties of NdMnO_(3) were investigated by variable temperature X-ray diffraction(XRD), scanning electron microscope(SEM) and variable temperature Raman spectra. The compound exhibits NTE properties in the orderly O' phase crystal structure. When the temperature is from 293 to 759 K, the ceramic NdMnO_(3) shows negative thermal expansion of-4.7×10^(-6)/K. As temperature increases, the ceramic NdMnO_(3) presents NTE property range from 759 to 1 007 K. The average linear expansion coefficient is-18.88×10^(-6)/K. The physical mechanism of NTE is discussed and clarified through experiments.
基金The authors gratefully acknowledge the support provided by the Postgraduate Research&Practice Program of Jiangsu Province(Grant No.KYCX18_0526)the Fundamental Research Funds for the Central Universities(Grant No.2018B682X14)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515110807).
文摘In the context of global mean square error concerning the number of random variables in the representation,the Karhunen–Loève(KL)expansion is the optimal series expansion method for random field discretization.The computational efficiency and accuracy of the KL expansion are contingent upon the accurate resolution of the Fredholm integral eigenvalue problem(IEVP).The paper proposes an interpolation method based on different interpolation basis functions such as moving least squares(MLS),least squares(LS),and finite element method(FEM)to solve the IEVP.Compared with the Galerkin method based on finite element or Legendre polynomials,the main advantage of the interpolation method is that,in the calculation of eigenvalues and eigenfunctions in one-dimensional random fields,the integral matrix containing covariance function only requires a single integral,which is less than a two-folded integral by the Galerkin method.The effectiveness and computational efficiency of the proposed interpolation method are verified through various one-dimensional examples.Furthermore,based on theKL expansion and polynomial chaos expansion,the stochastic analysis of two-dimensional regular and irregular domains is conducted,and the basis function of the extended finite element method(XFEM)is introduced as the interpolation basis function in two-dimensional irregular domains to solve the IEVP.
基金funded by the Ministry of Environment and Forestry of the Republic of Indonesia through the research funding assistance program。
文摘The Mutis-Timau Forest Complex,located on Timor Island,Indonesia,is a mountainous tropical forest area that gradually decreases due to deforestation and forest degradation.Previous modelling studies based on patterns indicate that deforestation primarily occurs at lower elevations and near the boundaries of forests and settlements,often associated with shifting cultivation by local farmers.This study adopts a process-based modelling approach,specifically the agent-based model,to simulate land changes,particularly farmers'expansion of agricultural land around the Mutis mountain forest.The underlying concept of this agent-based approach is the interaction between the human and environmental systems.Farmers,representing the human system,interact with the land,which represents the environmental system,through land use decision-making mechanisms.The research was conducted in the Community Forest of the Timor Tengah Utara District,one of the sites within the Mutis-Timau Forest Complex with the highest deforestation rate.Land use change simulations were performed using agent-based modelling from 1999 to 2030,considering the socio-economic conditions of farmers,spatial preferences,land use decisions,and natural transitions.The results revealed that the agricultural area increased by 14%under the Business as Usual scenario and 5%under the Reducing Emission from Deforestation and Forest Degradation scenario,compared to the initial agricultural area of 245 hectares.The probability of farmers deciding to extend agricultural activities was positively associated with the number of livestock maintained by farmers and the size of the village area.Conversely,the likelihood of farmers opting for agricultural extensification decreased with an increase in the area of private land and the farmer's age.These findings are crucial for the managers of the Mutis-Timau Forest Complex and other relevant stakeholders,as they aid in arranging actions to combat deforestation,designing proper forest-related policies,and providing support for initiatives such as reducing emissions from deforestation and forest degradation programs or further incentive schemes.
基金financially supported by the National Natural Science Foundation of China(52375204)the World First Class University and First Class Academic Discipline Construction Funding 2023(0206023GH0202,0206023SH0201)+1 种基金the Shenzhen Science and Technology R&D Funds(20200813100712001)the Fundamental Research Funds for the Central Universities(0604023GH0202079,0604023SH0201079)
文摘In response to the ongoing energy crisis,advancing the field of electrocatalytic water splitting is of utmost significance,necessitating the urgent development of high-performance,cost-effective,and durable hydrogen evolution reaction catalysts.But the generated gas bubble adherence to the electrode surface and sluggish separation contribute to significant energy loss,primarily due to the insufficient exposure of active sites,thus substantially hindering electrochemical performance.Here,we successfully developed a superaerophobic catalytic electrode by loading phosphorus-doped nickel metal(NiP_(x))onto various conductive substrates via an electrodeposition method.The electrode exhibits a unique surface structure,characterized by prominent surface fissures,which not only exposes additional active sites but also endows the electrode with superaerophobic properties.The NiP_(x)/Ti electrode demonstrates superior electrocatalytic activity for hydrogen evolution reaction,significantly outperforming a platinum plate,displaying an overpotential of mere 216 mV to achieve a current density of-500 mA cm^(-2) in 1 M KOH.Furthermore,the NiP_(x)/Ti electrode manifests outstanding durability and robustness during continuous electrolysis,maintaining stability at a current density of-10 mA cm^(-2) over a duration of 2000 h.Owing to the straightforward and scalable preparation methods,this highly efficient and stable NiP_(x)/Ti electrocatalyst offers a novel strategy for the development of industrial water electrolysis.