The volume change behavior of natural gas hydrate-bearing sediment is essential as it influences settlement,strength,and stiffness,which directly affect the stability of hydrate reservoirs during hydrate extraction or...The volume change behavior of natural gas hydrate-bearing sediment is essential as it influences settlement,strength,and stiffness,which directly affect the stability of hydrate reservoirs during hydrate extraction or in response to environmental changes.The volume change is influenced not only by stress but also by the formation and dissociation of hydrates.This study adopted a customized apparatus for one-dimensional compression tests,allowing independent control of gas pressure and effective stress.Tests were conducted on samples with different hydrate saturations along various temperature-gas pressure-effective stress paths,yielding some conclusions related to compressibility and creep.An unusual phenomenon was observed under low-stress conditions:hydrate formation led to shrinkage rather than expansion.Three potential mechanisms behind this occurrence were discussed.As hydrate saturation increases,the yield stress rises while the compression and swelling indexes remain minimally affected.After hydrate dissociation,the compression curve of hydrate-bearing sediment drops to that of hydrate-free sediment.Once hydrate is formed,the compression curve of hydrate-free sediment gradually approaches that of hydrate-bearing sediment during the subsequent loading.Under low-stress conditions,the creep of both hydrate-free and hydrate-bearing sediments is very weak.However,when stress increases,significantly beyond the yield stress,the creep of both sediments increases significantly,with hydrate-bearing sediment exhibiting much greater creep than hydrate-free sediment.展开更多
The porosity of titanium foams obtained from the space holder technique was theoretically analyzed in the cases of volume shrinking, retaining and expanding during sintering. The relationship between porosity and spac...The porosity of titanium foams obtained from the space holder technique was theoretically analyzed in the cases of volume shrinking, retaining and expanding during sintering. The relationship between porosity and spacer content was compared under different conditions. The kind of volume change of macropores during sintering was discussed. The results indicate that the relationship between porosity and spacer content depends on the decreased volume of macropores and the volume of micropores in cell-walls in the first case, while the porosity will be greater than the spacer content for the other two cases. It proves that the volume change of macropores during sintering decreases based on theory and practice.展开更多
The wide engineered application of compacted expansive soils necessitates understanding their behavior under field conditions.The results of this study demonstrate how seasonal climatic variation and stress and bounda...The wide engineered application of compacted expansive soils necessitates understanding their behavior under field conditions.The results of this study demonstrate how seasonal climatic variation and stress and boundary conditions individually or collectively influence the hydraulic and volume change behavior of compacted highly expansive soils.The cyclic wetting and drying(CWD)process was applied for two boundary conditions,i.e.constant stress(CS)and constant volume(CV),and for a wide range of axial stress states.The adopted CWD process affected the hydraulic and volume change behaviors of expansive soils,with the first cycle of wetting and drying being the most effective.The CWD process under CS conditions resulted in shrinkage accumulation and reduction in saturated hydraulic conductivity(k sat).On the other hand,CWD under CV conditions caused a reduction of swell pressure while has almost no impact on k sat.An elastic response to CWD was achieved after the third cycle for saturated hydraulic conductivity(k sat),the third to fourth cycle for the volume change potential under the CV conditions,and the fourth to fifth cycle for the volume change potential under the CS conditions.Finally,both swell pressure(s s)and saturated hydraulic conductivity(k sat)are not fundamental parameters of the expansive soil but rather depend on stress,boundary and wetting conditions.展开更多
VS_(2) has attracted increasing attention as a cathode material for aqueous zinc ion batteries because of its proper large layer spacing,weak interlayer interactions,multiple valence states of V,and excellent electric...VS_(2) has attracted increasing attention as a cathode material for aqueous zinc ion batteries because of its proper large layer spacing,weak interlayer interactions,multiple valence states of V,and excellent electrical conductivity,but its large volume change during charging and discharging leads to poor cycling stability.Herein,we report a one-step hydrothermal synthesis of VS_(2) microflowers with proper lamellar spacing,which provides a stable framework for the insertion/deinsertion of zinc ions and enhances the cycling stability,delivering an initial charge capacity of 128.3 mAh g^(-1) at 3 A g^(-1) and maintains a charge capacity of 100.1 mAh g^(-1) after 900 cycles.In addition,the optimized VS_(2) cathode shows specific capacities of 215.7 and 150.5 mAh g^(-1) at the current densities of 0.1 and 2 A g^(-1),respectively,demonstrating that the microflower structure with a high specific surface area and a short diffusion distance also significantly enhances the rate performance.展开更多
For the purpose of describing the deformation characteristics of rocks,the effect of volume changes on mechanical properties of rocks should be taken into account with relation to the development of constitutive model...For the purpose of describing the deformation characteristics of rocks,the effect of volume changes on mechanical properties of rocks should be taken into account with relation to the development of constitutive model.Firstly,rocks are divided into three parts,i.e.,voids,a damaged part and an undamaged part in the course of loading.The void ratio was applied to describing the changes of voids or pores during the deformation process.Then,using statistical damage theory,a constitutive model was developed for rocks to describe their strain softening and hardening on the basis of investigating the relationship between the net stress and apparent stress,in which the influence of volume changes on rock behavior was correctly taken into account,such as the initial phase of compaction and the latter stage of dilation.Thirdly,a method of determining model parameters was also presented.Finally,this model was used to compare the theoretical results with those observed from experiments under conventional triaxial loading conditions.展开更多
The paper describes an investigation into the volume change of cement mortar specimen at the three kinds of different curing schedules including 20℃and 5% Na2SO4 solution curing, tap water standard curing, 50% RH cur...The paper describes an investigation into the volume change of cement mortar specimen at the three kinds of different curing schedules including 20℃and 5% Na2SO4 solution curing, tap water standard curing, 50% RH curing for 90 days. The testing results of hydration heat, chemical shrinking and XRD prove that calcined phosphogypsum has evident excitation effect on the activity of high calcium ash and steel slag. Simultaneously, calcined phosphogypsum has the function of decreasing volume shrinkage to blended cement possessing steel slag and high calcium ash. In sulfate curing, calcined phosphogypsum can avoid the phenomenon of protrude apex of the blended cement.展开更多
Lithium metal is the ultimate anode material for next-generation high-energy batteries.Yet,the practical application of lithium metal anodes is limited by the formation of Li dendrites and large volume changes.Herein,...Lithium metal is the ultimate anode material for next-generation high-energy batteries.Yet,the practical application of lithium metal anodes is limited by the formation of Li dendrites and large volume changes.Herein,an effective multi-dimensional hybrid flexible film(MD-HFF)composed of iodine ion(0 dimension),CNTs(1 dimension)and graphene(2 dimensions)is designed for regulating Li deposition and mitigating volume changes.The multi-dimensional components serve separate roles:(1)iodine ion enhances the conductivity of the electrode and provides lithiophilic sites,(2)CNTs strengthen interlaminar conductance and mechanical strength,acting as a spring in the layered structure to alleviate volume changes during Li plating and stripping and(3)graphene provides mechanical flexibility and electrical conductivity.The resulting MD-HFF material supports stable Li plating/stripping and high Coulombic efficiency(99%)over 230 cycles at 1 mA cm^(-2) with a deposition capacity of 1 mAh cm^(-2).Theoretical calculations indicate that LiI contributes to the lateral growth of Li on the MD-HFF surface,thereby inhibiting the formation of Li dendrites.When paired with a typical NCM811 cathode,the assembled MD-HFF‖NCM811 cell exhibit improved capability and stable cycling performance.This research serves to guide material design in achieving Li anode materials that do not suffer from dendrite formation and volume changes.展开更多
In the condition of 20℃, 5% sulfate liquor curing, standard tap water curing and 50% RH curing-three different curing environments, the volume change of steel slag blended cement influenced by environmental factors w...In the condition of 20℃, 5% sulfate liquor curing, standard tap water curing and 50% RH curing-three different curing environments, the volume change of steel slag blended cement influenced by environmental factors was studied. With steel slag addition 10%, 30%, 50%, from 90 days to 356 days, the relationship of shrinkage and three different curing environments is: dry curing environ-ment>tap water curing environment>sulfate curing environment. But, the sample shrinkage in 28 days has much difference with the curing environment, which has no obvious orderliness. The different effects on blended cement containing steel slag in different environmental factors were analyzed using SEM.展开更多
This paper presents the first measurement of multi-decadal thickness and volume changes(1969?2000)of the Dongkemadi Ice Field(DIF)in the Tanggula Mountains,central Qinghai-Tibetan Plateau,China,using multi-source remo...This paper presents the first measurement of multi-decadal thickness and volume changes(1969?2000)of the Dongkemadi Ice Field(DIF)in the Tanggula Mountains,central Qinghai-Tibetan Plateau,China,using multi-source remote sensing data.These include the Shuttle Radar Topography Mission(SRTM)Digital Elevation Model(DEM)acquired in February,2000,a DEM generated by digitising analogue topographic maps from 1969,and Landsat ETM?imagery from 2000.Digital glacier outlines and GIS-based processing were used to calculate an elevation difference map to evaluate the relative elevation error of these two DEMs over ice-free areas.This methodwas also used to identify regions of glacier elevation thinning and thickening corresponding to glacier mass loss and gain.Analysis of 67,520 points on flat grass and rock terrain surrounding the DIF,with a slope less than 258,showed a mean elevation difference of?0.90 m and a standard deviation of 5.58 m.A thickness change error within 96 m was estimated.Between 1969 and 2000,76.51%of the whole DIF area appeared to be thinning while 23.49%showed thickening.The average glacier surface thinning was?12.58 m with a standard deviation of 18.29 m and the estimated volume loss was 1.17 km 3.The standard deviation of volume change was 0.0006 km 3 over the DIF.A thinning rate up to 0.4190.194 m a?1 or 0.038 km 3 a?1 for the volume loss was observed for the whole ice field,which seems to be evidence for the ongoing retreat of glaciers on the Qinghai-Tibetan Plateau.It was found that the spatial thickness change pattern derived from the remote sensing method was consistent with the thickness change results of the Small Dongkemadi Glacier(SDG)from field measurements.The estimated error of the annual thickness change rate was on the order of 5%.The relationship between elevation change and absolute glacier elevation over typical glaciers was also analysed,showing considerable variability.These changes have possibly resulted from increased temperature and decreased precipitation in this region.展开更多
All-solid-state lithium batteries(ASSLBs)are regarded as the representative of next-generation energy storage technology.It can solve the flammability hazard of liquid lithium batteries and their theoretical energy de...All-solid-state lithium batteries(ASSLBs)are regarded as the representative of next-generation energy storage technology.It can solve the flammability hazard of liquid lithium batteries and their theoretical energy density can reach exceeding 500 Wh·kg^(-1).Silicon is one of the most attractive anode materials for high-energy ASSLBs because of its high theoretical capacity and low working potential.However,Si anode faces two key problems in practical applications.Firstly,the side reaction between Si and sulfide-based solid-state electrolytes is serious,which can form unstable interfacial phases,significantly increase interfacial impedance and deplete active lithium.Secondly,electrical/ionic contact loss caused by volume change of Si electrode during lithiation/delithiation process results in significant initial capacity loss and poor cycling stability.For this reason,a simple liquidphase approach was taken to form Li_(x)SiS_(y)layer-coated Si nanoparticles in-situ,and composite electrodes were prepared in this way.High initial coulombic efficiency(ICE)and stable cyclability for sulfide-based ASSLBs can be achieved.The results show that the Si@Li_(x)SiS_(y)-Li_(3)PS_(4)-C composite electrode exhibits a higher ICE of 77.5%at 0.13 mA·cm^(-2)compared to that of 55.9%for Si-Li_(3)PS_(4)-C electrode and a more stable cycling performance without external pressure.This indicates that the direct contact between Si and Li_(3)PS_(4)electrolyte is effectively blocked by coating with a Li_(x)SiS_(y)layer.Stable interface between Si and Li_(3)PS_(4)electrolyte can be obtained and prevent the side reactions between them.Both the stable interface and partial prelithiation of Si electrode is favorable for high initial reversibility.At the same time the presence of the coating layer reduces the mechanical stress due to the volume change of the Si particles and ensures a good stress relief.The greatly improved interfacial stability and favorable stress release ensured by the conformal coating layer can thus lead to good electrochemical performance of Si electrode in ASSLBs.展开更多
Compacted clays are widely used as barriers in municipal solid waste(MSW)landfills due to their low permeability,and the hydro-mechanical behaviour of such materials can be greatly affected by environmental conditions...Compacted clays are widely used as barriers in municipal solid waste(MSW)landfills due to their low permeability,and the hydro-mechanical behaviour of such materials can be greatly affected by environmental conditions.In this study,a series of wetting-drying(W-D)cycle tests and hydraulic conductivity tests were conducted on compacted red clay-bentonite mixtures.Various concentrations of NaCl solution were introduced during wetting to investigate the chemical effects.Scanning electron microscopy(SEM)and mercury intrusion porosimetry(MIP)tests were performed to analyze the evolution of soil microstructure.Results indicate that the compacted mixtures undergo cumulative shrinkage during W-D cycles,reaching an elastic state after three cycles.The hydraulic conductivity decreases as the bentonite content increases,becoming lower than 1×10^(-9)m/s when the bentonite content exceeds 10%,which satisfies the requirement for waste barriers.For a given bentonite content,the relationship between the logarithm of hydraulic conductivity and the void ratio can be well described by a linear regression equation.Additionally,the hydraulic conductivity initially increases and then decreases during the W-D cycles,peaking during the second wetting process.The presence of NaCl solution accelerates microstructural evolution and cumulative shrinkage,particularly in pure red clay.Therefore,adding an appropriate amount of bentonite mitigates the effect of NaCl solution on the volume change.Furthermore,the addition of bentonite exhibits a dual effect:the lubrication effect dominates in the mixtures with low bentonite content,while the filling effect prevails as volume change decreases due to the restriction of aggregates rearrangement when the bentonite content is high enough to fill the macropores.展开更多
Variability in moisture content is a common condition in natural soils.It influences soil properties significantly.A comprehensive understanding of the evolution of soil microstructure in wetting/drying process is of ...Variability in moisture content is a common condition in natural soils.It influences soil properties significantly.A comprehensive understanding of the evolution of soil microstructure in wetting/drying process is of great significance for interpretation of soil macro hydro-mechanical behavior.In this review paper,methods that are commonly used to study soil microstructure are summarized.Among them are scanning electron microscope(SEM),environmental SEM(ESEM),mercury intrusion porosimetry(MIP)and computed tomography(CT)technology.Moreover,progress in research on the soil microstructure evolution during drying,wetting and wetting/drying cycles is summarized based on reviews of a large body of research papers published in the past several decades.Soils compacted on the wet side of op-timum water content generally have a matrix-type structure with a monomodal pore size distribution(PSD),whereas soils compacted on the dry side of optimum water content display an aggregate structure that exhibits bimodal PSD.During drying,decrease in soil volume is mainly caused by the shrinkage of inter-aggregate pores.During wetting,both the intra-and inter-aggregate pores increase gradually in number and sizes.Changes in the characteristics of the soil pore structure significantly depend on stress state as the soil is subjected to wetting.During wetting/drying cycles,soil structural change is not completely reversible,and the generated cumulative swelling/shrinkage deformation mainly derives from macro-pores.Furthermore,based on this analysis and identified research needs,some important areas of research focus are proposed for future work.These areas include innovative methods of sample preparation,new observation techniques,fast quantitative analysis of soil structure,integration of microstructural parameters into macro-mechanical models,and soil microstructure evolution charac-teristics under multi-field coupled conditions.展开更多
Lithium-sulfur batteries with liquid electrolytes have been obstructed by severe shuttle effects and intrinsic safety concerns.Introducing inorganic solid-state electrolytes into lithium-sulfur systems is believed as ...Lithium-sulfur batteries with liquid electrolytes have been obstructed by severe shuttle effects and intrinsic safety concerns.Introducing inorganic solid-state electrolytes into lithium-sulfur systems is believed as an effective approach to eliminate these issues without sacrificing the high-energy density,which determines sulfidebased all-solid-state lithium-sulfur batteries.However,the lack of design principles for high-performance composite sulfur cathodes limits their further application.The sulfur cathode regulation should take several factors including the intrinsic insulation of sulfur,well-designed conductive networks,integrated sulfur-electrolyte interfaces,and porous structure for volume expansion,and the correlation between these factors into account.Here,we summarize the challenges of regulating composite sulfur cathodes with respect to ionic/electronic diffusions and put forward the corresponding solutions for obtaining stable positive electrodes.In the last section,we also outlook the future research pathways of architecture sulfur cathode to guide the develop high-performance all-solid-state lithium-sulfur batteries.展开更多
A total of 71,177 glaciers exist on the Qinghai-Tibet Plateau,according to the Randolph Glacier Inventory(RGI 6.0).Despite their large number,glacier ice thickness data are relatively scarce.This study utilizes digita...A total of 71,177 glaciers exist on the Qinghai-Tibet Plateau,according to the Randolph Glacier Inventory(RGI 6.0).Despite their large number,glacier ice thickness data are relatively scarce.This study utilizes digital elevation model data and ground-penetrating radar thickness measurements to estimate the distribution and variation of ice thickness of the Longbasaba Glacier using Glacier bed Topography(GlabTop),a full-width expansion model,and the Huss and Farinotti(HF)model.Results show that the average absolute deviations of GlabTop,the full-width expansion model,and the HF model are 9.8,15.5,and 10.9 m,respectively,indicating that GlabTop performs the best in simulating glacier thickness distribution.During 1980−2015,the Longbasaba Glacier thinned by an average of 7.9±1.3 m or 0.23±0.04 m/a,and its ice volume shrunk by 0.28±0.04 km3 with an average reduction rate of 0.0081±0.0001 km^3/a.In the investigation period,the area and volume of Longbasaba Lake expanded at rates of 0.12±0.01 km^2/a and 0.0132±0.0018 km3/a,respectively.This proglacial lake could potentially extend up to 5,000 m from the lake dam.展开更多
A large adiabatic temperature change(△T_(ad))is a prerequisite for the application of elastocaloric refriger-ation.Theoretically,a large volume change ratio(△V/V_(0))during martensitic transformation is favorable to...A large adiabatic temperature change(△T_(ad))is a prerequisite for the application of elastocaloric refriger-ation.Theoretically,a large volume change ratio(△V/V_(0))during martensitic transformation is favorable to enhance△T_(ad).However,the design or prediction of△V/V_(0)in experiments is a complex task because the structure of martensite changes simultaneously when the lattice parameter of austenite is tuned by mod-ifying chemical composition.So far,the solid strategy to tailor△V/V_(0)is still urgently desirable.In this work,a first-principles-based method was proposed to estimate△V/V_(0)for Ni-Mn-based alloys.With this method,the substitution of Ga for In is found to be an effective method to increase the value of△V/V_(0)for Ni-Mn-In alloys.Combined with the strategies of reducing the negative contribution of magnetic en-tropy change(via the substitution of Cu for Mn)and introducing strong crystallographic texture(through directional solidification),an outstanding elastocaloric prototype alloy of Ni_(50)(Mn_(28.5)Cu_(4.5))(In_(14)Ga_(3))was fabricated experimentally.At room temperature,a huge△T_(ad)of-19 K and a large specific adiabatic temperature change of 67.8 K/GPa are obtained.The proposed first-principle-assisted framework opens up the possibility of efficiently tailoring△V/V_(0)to promote the design of advanced elastocaloric refrigerants.展开更多
The expansion and contraction of an open-graded friction course(OGFC)with a nominal maximum aggregate size of 13.2 mm(OGFC-13)with three air void contents(AVCs)and six saturation degrees(SDs)exposed to freeze-thaw(FT)...The expansion and contraction of an open-graded friction course(OGFC)with a nominal maximum aggregate size of 13.2 mm(OGFC-13)with three air void contents(AVCs)and six saturation degrees(SDs)exposed to freeze-thaw(FT)cycles were measured using strain gauges.Cantabro tests were conducted on OGFC-13 specimens before and after FT cycles to evaluate the degradation of raveling resistance.The effects of SD,AVC,and the number of FT cycles on the expansion and contraction of OGFC-13 and degradation of raveling resistance were analyzed.Results show that OGFC with low water saturation will contract to stability during the freezing process,whereas fully saturated OGFC will contract first and then expand to be stable.OGFC with a medium saturation experienced three stages,namely,contraction,expansion,and contraction,during the freezing process.For the OGFC with a low SD,the decrease in the void content can effectively reduce the low temperature shrinkage.By contrast,for the OGFC with a high SD,lower void content produces more temperature shrinkage at the beginning of freezing and less expansion at the end of freezing.The decreases in SD and AVC can effectively improve the raveling resistance of OGFCs exposed to FT cycles.展开更多
Objective: to evaluate the value of LV diastolic function in hypertensive patients. Methods: the 106 cases of hypertension admitted in our hospital according to cardiac hypertrophy is divided into myocardial hypertrop...Objective: to evaluate the value of LV diastolic function in hypertensive patients. Methods: the 106 cases of hypertension admitted in our hospital according to cardiac hypertrophy is divided into myocardial hypertrophy (LVH) and no cardiac hypertrophy (N-LVH), and selected in the hospital of 50 healthy patients as a control group, the echocardiography, and comparative analysis of the LV diastolic volume change series parameters. Results: all serial parameters of LV diastolic volume change in hypertensive patients and controls (P <0.05), and VA、SVA、VAR、SVE、VER、SVER, VE / VA and VER / VAR between LVH and N-LVH (P <0.0 5). Conclusion: the series parameters of the LV diastolic function in hypertensive patients can provide important reference for early diagnosis of LV diastolic dysfunction.展开更多
ABSTRACT A decade-long pronounced increase in temperatures in the Arctic resulted in a global warming hotspot over the Greenland ice sheet(GrIS).Associated changes in the cryosphere were the consequence and led to a d...ABSTRACT A decade-long pronounced increase in temperatures in the Arctic resulted in a global warming hotspot over the Greenland ice sheet(GrIS).Associated changes in the cryosphere were the consequence and led to a demand for monitoring glacier changes,which are one of the major parameters to analyze the responses of the GrIS to climate change.Long-term altimetry data(e.g.ICESat,CryoSat-2,and ICESat-2)can provide elevation changes over different periods,and many methods have been developed for altimetry alone to obtain elevation changes.In this work,we provided the long-term elevation change rate data of the GrIS in three different periods using ICESat data(from February 2003 to October 2009),Cryosat-2 data(from August 2010 to October 2018)and ICESat-2 data(from October 2018 to December 2020).Optimal methods were applied to the datasets collected by three different altimeters:crossover analysis for ICESat/ICESat-2 and the surface fit method for Cryosat-2.The data revealed that the elevation change rates of the GrIS were-12.19±3.81 cm/yr,-19.70±3.61 cm/yr and-23.39±3.06 cm/yr in the three different periods,corresponding to volume change rates of-210.20±25.34 km^(3)/yr,-339.11±24.01 km^(3)/yr and-363.33±20.37 km^(3)/yr,respectively.In general,the obtained results agree with the trends discovered by other studies that were also derived from satellite altimetry data.This dataset provides the basic data for research into the impact of climate change over the GrIS.The dataset is available at https://doi.org/10.57760/sciencedb.j00076.00121.展开更多
Silicon(Si)has emerged as a promising anode material for lithium-ion batteries(LIBs)due to its extremely high theoretical capacity of 4200 mAh·g^(-1).However,its practical application is limited by several critic...Silicon(Si)has emerged as a promising anode material for lithium-ion batteries(LIBs)due to its extremely high theoretical capacity of 4200 mAh·g^(-1).However,its practical application is limited by several critical challenges,including severe volume expansion and poor electrical conductivity.Herein,we employ a two-dimensional(2D)oxygen modification engineering approach to fabricate 2D oxygen-functionalized CaSi_(2)(CaSi_(2)O_(x))layers.During the preparation of 2D CaSi_(2) layers,O atoms are gradually incorporated onto their surface.The resulting 2D CaSi_(2)O_(x) layers have a thickness of 3-5 nm,closely matching the theoretical thickness of 6-10 layers.When used as lithium anodes,the 2D CaSi_(2)O_(x) layers exhibit exceptional electrochemical performance,maintaining stability over 3000 cycles at an ultrahigh current density of 30 A·g^(-1).By tailoring the surface properties,their pseudocapacitive charge storage mechanism is significantly enhanced,effectively overcoming the intrinsic limitations of traditional Si anodes.This study highlights the promise of 2D surface engineering in the development of advanced materials for next-generation LIBs.展开更多
The last two to three decades have seen significant advances in the mechanics of unsaturated soils.It is now widely recognized that the fundamental principles in soil mechanics must cover both saturated and unsaturate...The last two to three decades have seen significant advances in the mechanics of unsaturated soils.It is now widely recognized that the fundamental principles in soil mechanics must cover both saturated and unsaturated soils.Nevertheless,there is still a great deal of uncertainties in the geotechnical community about how soil mechanics principles well-established for saturated soils can be extended to unsaturated soils.There is even wide skepticism about the necessity of such extension in engineering practice.This paper discusses some common pitfalls related to the fundamental principles that govern the volume change,shear strength and hydromechanical behaviour of unsaturated soils.It also attempts to address the issue of engineering relevance of unsaturated soil mechanics.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.42171135)the Science and Technology Program of CNOOC Research Institute(Grant No.2023OTKK03)the“CUG Scholar”Scientific Research Funds at China University of Geosciences(Project No.2022098).
文摘The volume change behavior of natural gas hydrate-bearing sediment is essential as it influences settlement,strength,and stiffness,which directly affect the stability of hydrate reservoirs during hydrate extraction or in response to environmental changes.The volume change is influenced not only by stress but also by the formation and dissociation of hydrates.This study adopted a customized apparatus for one-dimensional compression tests,allowing independent control of gas pressure and effective stress.Tests were conducted on samples with different hydrate saturations along various temperature-gas pressure-effective stress paths,yielding some conclusions related to compressibility and creep.An unusual phenomenon was observed under low-stress conditions:hydrate formation led to shrinkage rather than expansion.Three potential mechanisms behind this occurrence were discussed.As hydrate saturation increases,the yield stress rises while the compression and swelling indexes remain minimally affected.After hydrate dissociation,the compression curve of hydrate-bearing sediment drops to that of hydrate-free sediment.Once hydrate is formed,the compression curve of hydrate-free sediment gradually approaches that of hydrate-bearing sediment during the subsequent loading.Under low-stress conditions,the creep of both hydrate-free and hydrate-bearing sediments is very weak.However,when stress increases,significantly beyond the yield stress,the creep of both sediments increases significantly,with hydrate-bearing sediment exhibiting much greater creep than hydrate-free sediment.
基金Project(51174243)supported by the National Natural Science Foundation of ChinaProject(106112015CDJZR135502)supported by the Fundamental Research Funds for the Central Universities,China
文摘The porosity of titanium foams obtained from the space holder technique was theoretically analyzed in the cases of volume shrinking, retaining and expanding during sintering. The relationship between porosity and spacer content was compared under different conditions. The kind of volume change of macropores during sintering was discussed. The results indicate that the relationship between porosity and spacer content depends on the decreased volume of macropores and the volume of micropores in cell-walls in the first case, while the porosity will be greater than the spacer content for the other two cases. It proves that the volume change of macropores during sintering decreases based on theory and practice.
文摘The wide engineered application of compacted expansive soils necessitates understanding their behavior under field conditions.The results of this study demonstrate how seasonal climatic variation and stress and boundary conditions individually or collectively influence the hydraulic and volume change behavior of compacted highly expansive soils.The cyclic wetting and drying(CWD)process was applied for two boundary conditions,i.e.constant stress(CS)and constant volume(CV),and for a wide range of axial stress states.The adopted CWD process affected the hydraulic and volume change behaviors of expansive soils,with the first cycle of wetting and drying being the most effective.The CWD process under CS conditions resulted in shrinkage accumulation and reduction in saturated hydraulic conductivity(k sat).On the other hand,CWD under CV conditions caused a reduction of swell pressure while has almost no impact on k sat.An elastic response to CWD was achieved after the third cycle for saturated hydraulic conductivity(k sat),the third to fourth cycle for the volume change potential under the CV conditions,and the fourth to fifth cycle for the volume change potential under the CS conditions.Finally,both swell pressure(s s)and saturated hydraulic conductivity(k sat)are not fundamental parameters of the expansive soil but rather depend on stress,boundary and wetting conditions.
基金financially supported by the Ningbo Natural Science Foundation(No.202003N4054)the Fundamental Research Funds for the Central Universities.
文摘VS_(2) has attracted increasing attention as a cathode material for aqueous zinc ion batteries because of its proper large layer spacing,weak interlayer interactions,multiple valence states of V,and excellent electrical conductivity,but its large volume change during charging and discharging leads to poor cycling stability.Herein,we report a one-step hydrothermal synthesis of VS_(2) microflowers with proper lamellar spacing,which provides a stable framework for the insertion/deinsertion of zinc ions and enhances the cycling stability,delivering an initial charge capacity of 128.3 mAh g^(-1) at 3 A g^(-1) and maintains a charge capacity of 100.1 mAh g^(-1) after 900 cycles.In addition,the optimized VS_(2) cathode shows specific capacities of 215.7 and 150.5 mAh g^(-1) at the current densities of 0.1 and 2 A g^(-1),respectively,demonstrating that the microflower structure with a high specific surface area and a short diffusion distance also significantly enhances the rate performance.
基金Project(2006AA11Z104) supported by the National High-Tech Research and Development Program of China
文摘For the purpose of describing the deformation characteristics of rocks,the effect of volume changes on mechanical properties of rocks should be taken into account with relation to the development of constitutive model.Firstly,rocks are divided into three parts,i.e.,voids,a damaged part and an undamaged part in the course of loading.The void ratio was applied to describing the changes of voids or pores during the deformation process.Then,using statistical damage theory,a constitutive model was developed for rocks to describe their strain softening and hardening on the basis of investigating the relationship between the net stress and apparent stress,in which the influence of volume changes on rock behavior was correctly taken into account,such as the initial phase of compaction and the latter stage of dilation.Thirdly,a method of determining model parameters was also presented.Finally,this model was used to compare the theoretical results with those observed from experiments under conventional triaxial loading conditions.
基金Funded by the National Hi-Tech Research and Development Program ("863" Project) of China (No. 2005AA332010)
文摘The paper describes an investigation into the volume change of cement mortar specimen at the three kinds of different curing schedules including 20℃and 5% Na2SO4 solution curing, tap water standard curing, 50% RH curing for 90 days. The testing results of hydration heat, chemical shrinking and XRD prove that calcined phosphogypsum has evident excitation effect on the activity of high calcium ash and steel slag. Simultaneously, calcined phosphogypsum has the function of decreasing volume shrinkage to blended cement possessing steel slag and high calcium ash. In sulfate curing, calcined phosphogypsum can avoid the phenomenon of protrude apex of the blended cement.
基金supported by the Sichuan Province Science and Technology Support Program of 2020YFG0339, 2020YFH0097 and 2018GZ0007。
文摘Lithium metal is the ultimate anode material for next-generation high-energy batteries.Yet,the practical application of lithium metal anodes is limited by the formation of Li dendrites and large volume changes.Herein,an effective multi-dimensional hybrid flexible film(MD-HFF)composed of iodine ion(0 dimension),CNTs(1 dimension)and graphene(2 dimensions)is designed for regulating Li deposition and mitigating volume changes.The multi-dimensional components serve separate roles:(1)iodine ion enhances the conductivity of the electrode and provides lithiophilic sites,(2)CNTs strengthen interlaminar conductance and mechanical strength,acting as a spring in the layered structure to alleviate volume changes during Li plating and stripping and(3)graphene provides mechanical flexibility and electrical conductivity.The resulting MD-HFF material supports stable Li plating/stripping and high Coulombic efficiency(99%)over 230 cycles at 1 mA cm^(-2) with a deposition capacity of 1 mAh cm^(-2).Theoretical calculations indicate that LiI contributes to the lateral growth of Li on the MD-HFF surface,thereby inhibiting the formation of Li dendrites.When paired with a typical NCM811 cathode,the assembled MD-HFF‖NCM811 cell exhibit improved capability and stable cycling performance.This research serves to guide material design in achieving Li anode materials that do not suffer from dendrite formation and volume changes.
文摘In the condition of 20℃, 5% sulfate liquor curing, standard tap water curing and 50% RH curing-three different curing environments, the volume change of steel slag blended cement influenced by environmental factors was studied. With steel slag addition 10%, 30%, 50%, from 90 days to 356 days, the relationship of shrinkage and three different curing environments is: dry curing environ-ment>tap water curing environment>sulfate curing environment. But, the sample shrinkage in 28 days has much difference with the curing environment, which has no obvious orderliness. The different effects on blended cement containing steel slag in different environmental factors were analyzed using SEM.
基金supported by the Major State Basic Research Development Program of China(973 Program)(Nos.2010CB951403,2009CB723901)a grant from the Ministry of Science and Technology of the People’s Republic of China(No.2006FY110200).
文摘This paper presents the first measurement of multi-decadal thickness and volume changes(1969?2000)of the Dongkemadi Ice Field(DIF)in the Tanggula Mountains,central Qinghai-Tibetan Plateau,China,using multi-source remote sensing data.These include the Shuttle Radar Topography Mission(SRTM)Digital Elevation Model(DEM)acquired in February,2000,a DEM generated by digitising analogue topographic maps from 1969,and Landsat ETM?imagery from 2000.Digital glacier outlines and GIS-based processing were used to calculate an elevation difference map to evaluate the relative elevation error of these two DEMs over ice-free areas.This methodwas also used to identify regions of glacier elevation thinning and thickening corresponding to glacier mass loss and gain.Analysis of 67,520 points on flat grass and rock terrain surrounding the DIF,with a slope less than 258,showed a mean elevation difference of?0.90 m and a standard deviation of 5.58 m.A thickness change error within 96 m was estimated.Between 1969 and 2000,76.51%of the whole DIF area appeared to be thinning while 23.49%showed thickening.The average glacier surface thinning was?12.58 m with a standard deviation of 18.29 m and the estimated volume loss was 1.17 km 3.The standard deviation of volume change was 0.0006 km 3 over the DIF.A thinning rate up to 0.4190.194 m a?1 or 0.038 km 3 a?1 for the volume loss was observed for the whole ice field,which seems to be evidence for the ongoing retreat of glaciers on the Qinghai-Tibetan Plateau.It was found that the spatial thickness change pattern derived from the remote sensing method was consistent with the thickness change results of the Small Dongkemadi Glacier(SDG)from field measurements.The estimated error of the annual thickness change rate was on the order of 5%.The relationship between elevation change and absolute glacier elevation over typical glaciers was also analysed,showing considerable variability.These changes have possibly resulted from increased temperature and decreased precipitation in this region.
基金National Key R&D Program of China(2022YFB3506300)Guangdong-Foshan Joint Fund(2023A1515140091)Guangdong High-level Innovation Institute Project(2021B0909050001)。
文摘All-solid-state lithium batteries(ASSLBs)are regarded as the representative of next-generation energy storage technology.It can solve the flammability hazard of liquid lithium batteries and their theoretical energy density can reach exceeding 500 Wh·kg^(-1).Silicon is one of the most attractive anode materials for high-energy ASSLBs because of its high theoretical capacity and low working potential.However,Si anode faces two key problems in practical applications.Firstly,the side reaction between Si and sulfide-based solid-state electrolytes is serious,which can form unstable interfacial phases,significantly increase interfacial impedance and deplete active lithium.Secondly,electrical/ionic contact loss caused by volume change of Si electrode during lithiation/delithiation process results in significant initial capacity loss and poor cycling stability.For this reason,a simple liquidphase approach was taken to form Li_(x)SiS_(y)layer-coated Si nanoparticles in-situ,and composite electrodes were prepared in this way.High initial coulombic efficiency(ICE)and stable cyclability for sulfide-based ASSLBs can be achieved.The results show that the Si@Li_(x)SiS_(y)-Li_(3)PS_(4)-C composite electrode exhibits a higher ICE of 77.5%at 0.13 mA·cm^(-2)compared to that of 55.9%for Si-Li_(3)PS_(4)-C electrode and a more stable cycling performance without external pressure.This indicates that the direct contact between Si and Li_(3)PS_(4)electrolyte is effectively blocked by coating with a Li_(x)SiS_(y)layer.Stable interface between Si and Li_(3)PS_(4)electrolyte can be obtained and prevent the side reactions between them.Both the stable interface and partial prelithiation of Si electrode is favorable for high initial reversibility.At the same time the presence of the coating layer reduces the mechanical stress due to the volume change of the Si particles and ensures a good stress relief.The greatly improved interfacial stability and favorable stress release ensured by the conformal coating layer can thus lead to good electrochemical performance of Si electrode in ASSLBs.
基金the National Natural Science Foundation of China(Grant Nos.42372333 and 42072318)the China Scholarship Council(CSC)(Grant No.202306370029)。
文摘Compacted clays are widely used as barriers in municipal solid waste(MSW)landfills due to their low permeability,and the hydro-mechanical behaviour of such materials can be greatly affected by environmental conditions.In this study,a series of wetting-drying(W-D)cycle tests and hydraulic conductivity tests were conducted on compacted red clay-bentonite mixtures.Various concentrations of NaCl solution were introduced during wetting to investigate the chemical effects.Scanning electron microscopy(SEM)and mercury intrusion porosimetry(MIP)tests were performed to analyze the evolution of soil microstructure.Results indicate that the compacted mixtures undergo cumulative shrinkage during W-D cycles,reaching an elastic state after three cycles.The hydraulic conductivity decreases as the bentonite content increases,becoming lower than 1×10^(-9)m/s when the bentonite content exceeds 10%,which satisfies the requirement for waste barriers.For a given bentonite content,the relationship between the logarithm of hydraulic conductivity and the void ratio can be well described by a linear regression equation.Additionally,the hydraulic conductivity initially increases and then decreases during the W-D cycles,peaking during the second wetting process.The presence of NaCl solution accelerates microstructural evolution and cumulative shrinkage,particularly in pure red clay.Therefore,adding an appropriate amount of bentonite mitigates the effect of NaCl solution on the volume change.Furthermore,the addition of bentonite exhibits a dual effect:the lubrication effect dominates in the mixtures with low bentonite content,while the filling effect prevails as volume change decreases due to the restriction of aggregates rearrangement when the bentonite content is high enough to fill the macropores.
基金This work was supported by National Natural Science Founda-tion of China(Grant Nos.41925012 and 41902271)Natural Science Foundation of Jiangsu Province(Grant No.BK20211087).
文摘Variability in moisture content is a common condition in natural soils.It influences soil properties significantly.A comprehensive understanding of the evolution of soil microstructure in wetting/drying process is of great significance for interpretation of soil macro hydro-mechanical behavior.In this review paper,methods that are commonly used to study soil microstructure are summarized.Among them are scanning electron microscope(SEM),environmental SEM(ESEM),mercury intrusion porosimetry(MIP)and computed tomography(CT)technology.Moreover,progress in research on the soil microstructure evolution during drying,wetting and wetting/drying cycles is summarized based on reviews of a large body of research papers published in the past several decades.Soils compacted on the wet side of op-timum water content generally have a matrix-type structure with a monomodal pore size distribution(PSD),whereas soils compacted on the dry side of optimum water content display an aggregate structure that exhibits bimodal PSD.During drying,decrease in soil volume is mainly caused by the shrinkage of inter-aggregate pores.During wetting,both the intra-and inter-aggregate pores increase gradually in number and sizes.Changes in the characteristics of the soil pore structure significantly depend on stress state as the soil is subjected to wetting.During wetting/drying cycles,soil structural change is not completely reversible,and the generated cumulative swelling/shrinkage deformation mainly derives from macro-pores.Furthermore,based on this analysis and identified research needs,some important areas of research focus are proposed for future work.These areas include innovative methods of sample preparation,new observation techniques,fast quantitative analysis of soil structure,integration of microstructural parameters into macro-mechanical models,and soil microstructure evolution charac-teristics under multi-field coupled conditions.
基金supported by the National Natural Science Foundation of China(No.52272241)the start-up funding from Zhejiang University。
文摘Lithium-sulfur batteries with liquid electrolytes have been obstructed by severe shuttle effects and intrinsic safety concerns.Introducing inorganic solid-state electrolytes into lithium-sulfur systems is believed as an effective approach to eliminate these issues without sacrificing the high-energy density,which determines sulfidebased all-solid-state lithium-sulfur batteries.However,the lack of design principles for high-performance composite sulfur cathodes limits their further application.The sulfur cathode regulation should take several factors including the intrinsic insulation of sulfur,well-designed conductive networks,integrated sulfur-electrolyte interfaces,and porous structure for volume expansion,and the correlation between these factors into account.Here,we summarize the challenges of regulating composite sulfur cathodes with respect to ionic/electronic diffusions and put forward the corresponding solutions for obtaining stable positive electrodes.In the last section,we also outlook the future research pathways of architecture sulfur cathode to guide the develop high-performance all-solid-state lithium-sulfur batteries.
基金The work was funded by the National Natural Science Foundation of China(No.41701061,No.41761144075,No.41771075,and No.41271091).
文摘A total of 71,177 glaciers exist on the Qinghai-Tibet Plateau,according to the Randolph Glacier Inventory(RGI 6.0).Despite their large number,glacier ice thickness data are relatively scarce.This study utilizes digital elevation model data and ground-penetrating radar thickness measurements to estimate the distribution and variation of ice thickness of the Longbasaba Glacier using Glacier bed Topography(GlabTop),a full-width expansion model,and the Huss and Farinotti(HF)model.Results show that the average absolute deviations of GlabTop,the full-width expansion model,and the HF model are 9.8,15.5,and 10.9 m,respectively,indicating that GlabTop performs the best in simulating glacier thickness distribution.During 1980−2015,the Longbasaba Glacier thinned by an average of 7.9±1.3 m or 0.23±0.04 m/a,and its ice volume shrunk by 0.28±0.04 km3 with an average reduction rate of 0.0081±0.0001 km^3/a.In the investigation period,the area and volume of Longbasaba Lake expanded at rates of 0.12±0.01 km^2/a and 0.0132±0.0018 km3/a,respectively.This proglacial lake could potentially extend up to 5,000 m from the lake dam.
基金supported by the National Natural Science Foundation of China(Nos.51922026,51975111)the Fundamental Research Funds for the Central Universities(Nos.N2202015,N2230002,N2002021,N2105001)the 111 Project of China(Nos.BP0719037,B20029).
文摘A large adiabatic temperature change(△T_(ad))is a prerequisite for the application of elastocaloric refriger-ation.Theoretically,a large volume change ratio(△V/V_(0))during martensitic transformation is favorable to enhance△T_(ad).However,the design or prediction of△V/V_(0)in experiments is a complex task because the structure of martensite changes simultaneously when the lattice parameter of austenite is tuned by mod-ifying chemical composition.So far,the solid strategy to tailor△V/V_(0)is still urgently desirable.In this work,a first-principles-based method was proposed to estimate△V/V_(0)for Ni-Mn-based alloys.With this method,the substitution of Ga for In is found to be an effective method to increase the value of△V/V_(0)for Ni-Mn-In alloys.Combined with the strategies of reducing the negative contribution of magnetic en-tropy change(via the substitution of Cu for Mn)and introducing strong crystallographic texture(through directional solidification),an outstanding elastocaloric prototype alloy of Ni_(50)(Mn_(28.5)Cu_(4.5))(In_(14)Ga_(3))was fabricated experimentally.At room temperature,a huge△T_(ad)of-19 K and a large specific adiabatic temperature change of 67.8 K/GPa are obtained.The proposed first-principle-assisted framework opens up the possibility of efficiently tailoring△V/V_(0)to promote the design of advanced elastocaloric refrigerants.
基金The National Natural Science Foundation of China (No. 52178421)the Natural Science Foundation of Jiangsu Province(No. BK20191300)the Fundamental Research Funds for the Central Universities (No. B210202036)。
文摘The expansion and contraction of an open-graded friction course(OGFC)with a nominal maximum aggregate size of 13.2 mm(OGFC-13)with three air void contents(AVCs)and six saturation degrees(SDs)exposed to freeze-thaw(FT)cycles were measured using strain gauges.Cantabro tests were conducted on OGFC-13 specimens before and after FT cycles to evaluate the degradation of raveling resistance.The effects of SD,AVC,and the number of FT cycles on the expansion and contraction of OGFC-13 and degradation of raveling resistance were analyzed.Results show that OGFC with low water saturation will contract to stability during the freezing process,whereas fully saturated OGFC will contract first and then expand to be stable.OGFC with a medium saturation experienced three stages,namely,contraction,expansion,and contraction,during the freezing process.For the OGFC with a low SD,the decrease in the void content can effectively reduce the low temperature shrinkage.By contrast,for the OGFC with a high SD,lower void content produces more temperature shrinkage at the beginning of freezing and less expansion at the end of freezing.The decreases in SD and AVC can effectively improve the raveling resistance of OGFCs exposed to FT cycles.
文摘Objective: to evaluate the value of LV diastolic function in hypertensive patients. Methods: the 106 cases of hypertension admitted in our hospital according to cardiac hypertrophy is divided into myocardial hypertrophy (LVH) and no cardiac hypertrophy (N-LVH), and selected in the hospital of 50 healthy patients as a control group, the echocardiography, and comparative analysis of the LV diastolic volume change series parameters. Results: all serial parameters of LV diastolic volume change in hypertensive patients and controls (P <0.05), and VA、SVA、VAR、SVE、VER、SVER, VE / VA and VER / VAR between LVH and N-LVH (P <0.0 5). Conclusion: the series parameters of the LV diastolic function in hypertensive patients can provide important reference for early diagnosis of LV diastolic dysfunction.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA19070202)the Joint Project of the Chinese Academy of Science(CAS)entitled Using Earth Observations to Address Ecology and Environment Change in the Pan-Antarctic Cryosphere(No.183611KYSB20200059)the Open Research Program of the International Research Center of Big Data for Sustainable Development Goals(No.CBAS2022ORP04).
文摘ABSTRACT A decade-long pronounced increase in temperatures in the Arctic resulted in a global warming hotspot over the Greenland ice sheet(GrIS).Associated changes in the cryosphere were the consequence and led to a demand for monitoring glacier changes,which are one of the major parameters to analyze the responses of the GrIS to climate change.Long-term altimetry data(e.g.ICESat,CryoSat-2,and ICESat-2)can provide elevation changes over different periods,and many methods have been developed for altimetry alone to obtain elevation changes.In this work,we provided the long-term elevation change rate data of the GrIS in three different periods using ICESat data(from February 2003 to October 2009),Cryosat-2 data(from August 2010 to October 2018)and ICESat-2 data(from October 2018 to December 2020).Optimal methods were applied to the datasets collected by three different altimeters:crossover analysis for ICESat/ICESat-2 and the surface fit method for Cryosat-2.The data revealed that the elevation change rates of the GrIS were-12.19±3.81 cm/yr,-19.70±3.61 cm/yr and-23.39±3.06 cm/yr in the three different periods,corresponding to volume change rates of-210.20±25.34 km^(3)/yr,-339.11±24.01 km^(3)/yr and-363.33±20.37 km^(3)/yr,respectively.In general,the obtained results agree with the trends discovered by other studies that were also derived from satellite altimetry data.This dataset provides the basic data for research into the impact of climate change over the GrIS.The dataset is available at https://doi.org/10.57760/sciencedb.j00076.00121.
基金supported partially by project of the National Natural Science Foundation of China(Nos.62474064 and 52102203)the Fundamental Research Funds for the Central Universities(No.2024MS082)the NCEPU“Double First-Class”Program.
文摘Silicon(Si)has emerged as a promising anode material for lithium-ion batteries(LIBs)due to its extremely high theoretical capacity of 4200 mAh·g^(-1).However,its practical application is limited by several critical challenges,including severe volume expansion and poor electrical conductivity.Herein,we employ a two-dimensional(2D)oxygen modification engineering approach to fabricate 2D oxygen-functionalized CaSi_(2)(CaSi_(2)O_(x))layers.During the preparation of 2D CaSi_(2) layers,O atoms are gradually incorporated onto their surface.The resulting 2D CaSi_(2)O_(x) layers have a thickness of 3-5 nm,closely matching the theoretical thickness of 6-10 layers.When used as lithium anodes,the 2D CaSi_(2)O_(x) layers exhibit exceptional electrochemical performance,maintaining stability over 3000 cycles at an ultrahigh current density of 30 A·g^(-1).By tailoring the surface properties,their pseudocapacitive charge storage mechanism is significantly enhanced,effectively overcoming the intrinsic limitations of traditional Si anodes.This study highlights the promise of 2D surface engineering in the development of advanced materials for next-generation LIBs.
基金supported by the National Natural Science Foundation of China(Grant No.51208519)
文摘The last two to three decades have seen significant advances in the mechanics of unsaturated soils.It is now widely recognized that the fundamental principles in soil mechanics must cover both saturated and unsaturated soils.Nevertheless,there is still a great deal of uncertainties in the geotechnical community about how soil mechanics principles well-established for saturated soils can be extended to unsaturated soils.There is even wide skepticism about the necessity of such extension in engineering practice.This paper discusses some common pitfalls related to the fundamental principles that govern the volume change,shear strength and hydromechanical behaviour of unsaturated soils.It also attempts to address the issue of engineering relevance of unsaturated soil mechanics.
