Heat transfer and temperature evolution in overburden fracture and ground fissures are one of the essential topics for the identification of ground fissures via unmanned aerial vehicle(UAV) infrared imager. In this st...Heat transfer and temperature evolution in overburden fracture and ground fissures are one of the essential topics for the identification of ground fissures via unmanned aerial vehicle(UAV) infrared imager. In this study, discrete element software UDEC was employed to investigate the overburden fracture field under different mining conditions. Multiphysics software COMSOL were employed to investigate heat transfer and temperature evolution of overburden fracture and ground fissures under the influence of mining condition, fissure depth, fissure width, and month alternation. The UAV infrared field measurements also provided a calibration for numerical simulation. The results showed that for ground fissures connected to underground goaf(Fissure Ⅰ), the temperature difference increased with larger mining height and shallow buried depth. In addition, Fissure Ⅰ located in the boundary of the goaf have a greater temperature difference and is easier to be identified than fissures located above the mining goaf. For ground fissures having no connection to underground goaf(Fissure Ⅱ), the heat transfer is affected by the internal resistance of the overlying strata fracture when the depth of Fissure Ⅱ is greater than10 m, the temperature of Fissure Ⅱ gradually equals to the ground temperature as the fissures’ depth increases, and the fissures are difficult to be identified. The identification effect is most obvious for fissures larger than 16 cm under the same depth. In spring and summer, UAV infrared identification of mining fissures should be carried out during nighttime. This study provides the basis for the optimal time and season for the UAV infrared identification of different types of mining ground fissures.展开更多
Photoelectrochemical(PEC) technology provides a promising prospect for the transformation of polyethylene terephthalate(PET) plastic wastes to produce value-added chemicals.The PEC catalytic systems with high activity...Photoelectrochemical(PEC) technology provides a promising prospect for the transformation of polyethylene terephthalate(PET) plastic wastes to produce value-added chemicals.The PEC catalytic systems with high activity,selectivity and long-term durability are required for the future up-scaling industrial applications.Herein,we employed the interfacial modification strategy to develop an efficient and stable photoanode and evaluated its PEC activity for ethylene glycol(EG,derived from PET hydrolysate) oxidation to formic acid.The interfacial modification between Fe_(2)O_(3)semiconductor and Ni(OH)xcocatalyst with ultrathin TiO_(x) interlayer not only improved the photocurrent density by accelerating the kinetics of photogenerated charge carriers,but also kept the high Faradaic efficiency(over 95% in 30 h) towards the value-added formic acid product.This work proposes an effective method to promote the PEC activity and enhance the long-term stability of photoelectrodes for upcycling PET plastic wastes.展开更多
Background: The prognostic nutritional index(PNI) has been widely applied for predicting survival outcomes of patients with various malignant tumors. Although a low PNI predicts poor prognosis in patients with colorec...Background: The prognostic nutritional index(PNI) has been widely applied for predicting survival outcomes of patients with various malignant tumors. Although a low PNI predicts poor prognosis in patients with colorectal cancer after tumor resection, the prognostic value remains unknown in patients with stage Ⅲ colon cancer undergoing curative tumor resection followed by adjuvant chemotherapy. This study aimed to investigate the prognostic value of PNI in patients with stage III colon cancer.Methods: Medical records of 274 consecutive patients with stage Ⅲ colon cancer undergoing curative tumor resection followed by adjuvant chemotherapy with oxaliplatin and capecitabine between December 2007 and December2013 were reviewed. The optimal PNI cutoff value was determined using receiver operating characteristic(ROC) curve analysis. The associations of PNI with systemic inflammatory response markers, including lymphocyte-to-monocyte ratio(LMR), neutrophil-to-lymphocyte ratio(NLR), platelet-to-lymphocyte ratio(PLR), and C-reactive protein(CRP)level, and clinicopathologic characteristics were assessed using the Chi square or Fisher's exact test. Correlation analysis was performed using Spearman's correlation coefficient. Disease-free survival(DFS) and overall survival(OS)stratified by PNI were analyzed using Kaplan-Meier method and log-rank test, and prognostic factors were identified by Cox regression analyses.Results: The preoperative PNI was positively correlated with LMR(r= 0.483, P < 0.001) and negatively correlated with NLR(r =-0.441, P < 0.001), PLR(r =-0.607, P < 0.001), and CRP level(r =-0.333, P < 0.001). A low PNI(≤49.22)was significantly associated with short OS and DFS in patients with stage ⅢC colon cancer but not in patients with stage ⅢA/ⅢB colon cancer.In addition, patients with a low PNI achieved a longer OS and DFS after being treated with6-8 cycles of adjuvant chemotherapy than did those with < 6 cycles. Multivariate analyses revealed that PNI was independently associated with DFS(hazard ratios 2.001; 95% confidence interval 1.157-3.462; P = 0.013).Conclusion: The present study identified preoperative PNI as a valuable predictor for survival outcomes in patients with stage Ⅲ colon cancer receiving curative tumor resection followed by adjuvant chemotherapy.展开更多
The fracture behaviour and crack propagation features of coal under coupled static-dynamic loading conditions are important when evaluating the dynamic failure of coal.In this study,coupled static-dynamic loading test...The fracture behaviour and crack propagation features of coal under coupled static-dynamic loading conditions are important when evaluating the dynamic failure of coal.In this study,coupled static-dynamic loading tests are conducted on Brazilian disc(BD)coal specimens using a modified split Hopkinson pressure bar(SHPB).The effects of the static axial pre-stress and loading rate on the dynamic tensile strength and crack propagation characteristics of BD coal specimens are studied.The average dynamic indirect tensile strength of coal specimens increases first and then decreases with the static axial pre-stress increasing.When no static axial pre-stress is applied,or the static axial pre-stress is 30%of the static tensile strength,the dynamic indirect tensile strength of coal specimens shows an increase trend as the loading rate increases.When the static axial pre-stress is 60%of the static tensile strength,the dynamic indirect tensile strength shows a fluctuant trend as the loading rate increases.According to the crack propagation process of coal specimens recorded by high-speed camera,the impact velocity influences the mode of crack propagation,while the static axial pre-stress influences the direction of crack propagation.The failure of coal specimens is a coupled tensile-shear failure under high impact velocity.When there is no static axial pre-stress,tensile cracks occur in the vertical loading direction.When the static axial pre-stress is applied,the number of cracks perpendicular to the loading direction decreases,and more cracks occur in the parallel loading direction.展开更多
Coal bump refers to a sudden catastrophic failure of coal seam and usually can cause serious damages to underground mining facilities and staff. In this circumstance, this paper focuses on the recent achievements in t...Coal bump refers to a sudden catastrophic failure of coal seam and usually can cause serious damages to underground mining facilities and staff. In this circumstance, this paper focuses on the recent achievements in the mechanism and prevention techniques of coal bumps over the past five years in China.Based on theoretical analysis, laboratory experiment, numerical simulation and field test, the characteristics of coal bumps occurrence in China's coal mines were described, and the difference between coal bumps and rockbursts was also discussed. In addition, three categories of coal bumps induced by"material failure" were introduced, i.e. hard roof, floor strata and tectonic structures, in which the mechanism of coal bumps induced by geological structures was analyzed. This involves the bump liability and microstructure effects on bump-prone coal failure, the mechanism of coal bumps in response to fault reactivation, island face mining or hard roof failure. Next, the achievements in the monitoring and controlling methods of coal bumps were reviewed. These methods involve the incorporated prediction system of micro-seismicity and mining-induced pressure, the distributed micro-seismic monitoring system, energy absorption support system, bolts with constant resistance and large elongation,and the "multi-stage" high-performance support. Finally, an optimal mining design is desirable for the purpose of coal bump mitigation.展开更多
Irregular shape workface would result in the presence of coal pillar, which leads to high stress concentration and possibly induces coal bumps. In order to study the coal bump mechanism of pillars, static and dynamic ...Irregular shape workface would result in the presence of coal pillar, which leads to high stress concentration and possibly induces coal bumps. In order to study the coal bump mechanism of pillars, static and dynamic stress overlapping(SDSO) method was proposed to explain the impacts of static stress concentration and tremors induced by mining activities. The stress and deformation in surrounding rock of mining face were analyzed based on the field case study at 1303 workface in Zhaolou Coal Mine in China.The results illustrate that the surrounding rock of a workface could be divided into four different zones,i.e., residual stress zone, stress decrease zone, stress increase zone and original stress zone. The stress increase zone is prone to failure under the SDSO impact loading conditions and will provide elastic energy for inducing coal bump. Based on the numerical modelling results, the evolution of static stress in coal pillar as the size of gob increasing was studied, and the impact of dynamic stress was investigated through analyzing the characteristics of tremor activities. The numerical results demonstrate the peak value of vertical stress in coal pillar rises from about 30 MPa with mining distance 10 m to 52.6 MPa with mining distance 120 m, and the location of peak stress transfers to the inner zone of coal pillars as the workface moves forward. For the daily tremor activities, tremors with high energy released indicate high dynamic stress disturbance on the surrounding rock, therefore, the impact of dynamic stressing is more serious during workface extension period because the tremor frequency and average energy after workface extension are higher than those before the workface extension.展开更多
Lithium-sulfur(Li-S)batteries have great potential in next-generation energy storage due to its high theoretical specific capacity and energy density.However,there are several challenges to the practical application o...Lithium-sulfur(Li-S)batteries have great potential in next-generation energy storage due to its high theoretical specific capacity and energy density.However,there are several challenges to the practical application of Li-S batteries including the growth of lithium dendrites and the shuttle effect of polysulfide.Introducing interlayeres(freestanding or coated on the separator)is an effective approach to reduce these obstacles and improve the electrochemical performance of Li-S batteries.In this review,we briefly summarize the interlayer materials and structures modified on both cathodic and anodic sides including(ⅰ)carbon-based materials,(ⅱ)polymers,(ⅲ)inorganic metal compounds,(iv)metal-organic frameworks,as well as(v)the novel separators in recent years.We also systematically address the fabrication processes,assembling methods,and functions of interlayers for enhancing the performance of Li-S batteries.Furthermore,the prospects and outlooks of the future development of advanced interlayers and separators are also presented.展开更多
Surface passivation via post-treatment with organic reagents is a popular strategy to improve the stability and efficiency of perovskite solar cell. However, organic passivation still suffers from the weak bonding bet...Surface passivation via post-treatment with organic reagents is a popular strategy to improve the stability and efficiency of perovskite solar cell. However, organic passivation still suffers from the weak bonding between organic chemicals and perovskite layers. Here we reported a facile inorganic layer passivating method containing strong Pb–S bonding by using ammonium sulfide treatment. A compact PbS_x layer was in-situ formed on the top surface of the perovskite film, which could passivate and protect the perovskite surface to enhance the performance and stability. Our novel inorganic passivation layer strategy demonstrates great potential for the development of high efficiency hybrid and robust perovskite optoelectronics.展开更多
As coal mining is extended from shallow to deep areas along the western coalfield,it is of great significance to study weakly cemented sandstone at different depths for underground mining engineering.Sandstones from d...As coal mining is extended from shallow to deep areas along the western coalfield,it is of great significance to study weakly cemented sandstone at different depths for underground mining engineering.Sandstones from depths of 101.5,203.2,317.3,406.9,509.9 and 589.8 m at the Buertai Coal Mine were collected.The characteristic strength,acoustic emission(AE),and energy evolution of sandstone during uniaxial compression tests were analyzed.The results show that the intermediate frequency(125-275 kHz)of shallow rock mainly occurs in the postpeak stage,while deep rock occurs in the prepeak stage.The initiation strength and damage strength of the sandstone at different depths range from 0.23 to 0.50 and 0.63 to 0.84 of peak strength(σ_(c)),respectively,decrease exponentially and are a power function with depth.The precursor strength ranges from 0.88σ_(c)to 0.99σ_(c),increases with depth before reaching a depth of 300 m,and tends to stabilize after 300 m.The ratio of the initiation strength to the damage strength(k)ranges from 0.25 to 0.62 and decreases exponentially with depth.The failure modes of sandstone at different depths are tension-dominated mixed tensile-shear failure.Shear failure mainly occurs at the unstable crack propagation stage.The count of the shear failure bands before the peak strength increases gradually,and increases first and then decreases after the peak strength with burial depth.The cumulative input energy,released elastic energy and dissipated energy increase with depth.The elastic release rate ranges from 0.46×10^(-3)to 198.57×10^(-3)J/(cm^(3)s)and increases exponentially with depth.展开更多
The organic–inorganic hybrid perovskite solar cells(PSCs)have demonstrated their unprecedented high efficiency and potential for commercialization.The volatile organic components in the hybrid perovskite crystal stru...The organic–inorganic hybrid perovskite solar cells(PSCs)have demonstrated their unprecedented high efficiency and potential for commercialization.The volatile organic components in the hybrid perovskite crystal structure are still a big challenge for long-term stabilities.Recently,inorganic CsPbI3 perovskite has attracted much attention because of its superior chemical stability over the prevailing hybrid organic–inorganic perovskite and the most suitable band gap among all-inorganic perovskites.Nevertheless,CsPbI3 suffers from phase instability and low photovoltaic(PV)performance due to its undesirable tolerant factor.Much research effort has been devoted into stabilization of CsPbI3.In this perspective,we review the recent progress on chemical engineering processes for the stabilization of inorganic CsPbI3 perovskite for high-efficiency PVs.We also discuss the importance of understanding mechanism behind stabilization of CsPbI3 perovskite film and the development of inorganic CsPbI3-based highly efficient and stable PSCs.展开更多
The mixed-cation lead halide perovskites have emerged as a new class of promising light harvesting materials for solar cells. The formamidinium(FA), methylammonium(MA) and Cs cations are widely studied in the field of...The mixed-cation lead halide perovskites have emerged as a new class of promising light harvesting materials for solar cells. The formamidinium(FA), methylammonium(MA) and Cs cations are widely studied in the field of mixed-cation perovskites. Here, we have investigated ethylammonium(EA) as an alternative cation to fabricate a mixed-cation perovskite of MA_(1-x)EA_xPbI_3. We have characterized the materials using the X-ray diffraction(XRD), scanning electron microscope(SEM), and UV–vis spectrum. Our results have confirmed the successful incorporation of EA cations into MAPbI_3. Interestingly, the optimal amount of EA to achieve the best performance is quite low. This is different from the FA–MA mixed-cation perovskites although EA and FA have similar radii. In short, the EA–MA mixed-cation perovskite has some material and device properties highly distinguishable from the FA–MA one.展开更多
In the enhanced geothermal system(EGS),the injected fluid will induce shear sliding of rock fractures(i.e.,hydroshearing),which consequently,would increase the fracture aperture and improve the heat transfer efficienc...In the enhanced geothermal system(EGS),the injected fluid will induce shear sliding of rock fractures(i.e.,hydroshearing),which consequently,would increase the fracture aperture and improve the heat transfer efficiency of the geothermal reservoir.In this study,theoretical analysis,experimental research and numerical simulation were performed to uncover the permeability and heat transfer enhancement mechanism of the Hot-Dry-Rock(HDR)mass under the impact of shearing.By conducting the direct shear test with the fractured rock samples,the evolution process of fracture aperture during the shearing tests was observed,during which process,cubic law was adopted to depict the rock fracture permeability.To investigate the seepage characteristics and temperature distribution of the fractured HDR under the influence of shearing,a simulation study of shear-seepage-heat transfer in a fractured rock mass has been conducted to validate the observed shear-induced fracture dilation during the direct shear test.The results demonstrate that(1)the hydroshearing increases the dilation of granite fracture and enhances the permeability of the HDR rock mass,while the temperature around the HDR fracture will reduce.(2)Fracture roughness is of vital importance to enhance the permeability during the shearing tests.To be more specific,a rougher fracture always implies a higher permeability and a greater heat extraction efficiency.(3)The shear induced heat extracting efficiency is dominated by the increased fluid flux in the earlier period of the EGS reservoir,and this efficiency is controlled by the outlet water temperature since the fluid flux becomes stable after the shearing test.Therefore,balancing the hydroshearing enhanced heat extraction efficiency and EGS reservoir lifespan would be significant to the sustainable development and utilization of geothermal energy.展开更多
Cesium lead iodide(CsPbI_(3)) perovskite has gained great attention in the photovoltaic(PV) community because of its unique optoelectronic properties, good chemical stability and appropriate bandgap for sunlight harve...Cesium lead iodide(CsPbI_(3)) perovskite has gained great attention in the photovoltaic(PV) community because of its unique optoelectronic properties, good chemical stability and appropriate bandgap for sunlight harvesting applications. However, compared to solar cells fabricated from organic-inorganic hybrid perovskites, the commercialization of devices based on all-inorganic CsPbI_(3) perovskites still faces many challenges regarding PV performance and long-term stability. In this work, we discovered that tetrabutylammonium bromide(TBABr) post-treatment to CsPbI_(3) perovskite films could achieve synergistic stabilization with both TBA+cation intercalation and Br-doping. Such TBA^(+) cation intercalation leads to onedimensional capping with TBAPb I3 perovskite formed in situ, while the Br-induced crystal secondary growth helps effectively passivate the defects of CsPbI_(3) perovskite, thus enhancing the stability. In addition, the incorporation of TBABr can improve energy-level alignment and reduce interfacial charge recombination loss for better device performance. Finally, the highly stable TBABr-treated CsPbI_(3)-based perovskite solar cells show reproducible photovoltaic performance with a champion efficiency up to 19.04%, while retaining 90% of the initial efficiency after 500 h storage without encapsulation.展开更多
FA-Cs mixed-cation perovskite has been reported as a promising candidate for obtaining highly efficient and stable photovoltaic devices.Phenylethylamine iodide(PEAI)post-treatment is a widely used and effective method...FA-Cs mixed-cation perovskite has been reported as a promising candidate for obtaining highly efficient and stable photovoltaic devices.Phenylethylamine iodide(PEAI)post-treatment is a widely used and effective method for surface passivation of FA-Cs perovskite layer in devices.However,it is still controversial whether the PEAI post-treatment would form two-dimensional(2D)perovskite PEA_(2)PbI_(4) capping layer or just result in PEA+terminated surface.Here in this work,the function of PEAI post-treatment on FA-Cs mixed-cation perovskite FA_(1-x)Cs_(x)PbI_(3)(x=0.1–0.9)with varied Cs contents is elucidated.With increased Cs content,the FA-Cs perovskite shows higher resistance to the cation exchange between FA+and PEA+.This Cs-content-dependent cation exchange results in the different PEAI reaction preferences with FA-Cs mixed-cation perovskites.Furthermore,higher Cs content with stronger resistance to cation exchange reaction leads to a wider processing window for post-treatment and defect passivation,which is beneficial for the fabrication of large-scale photovoltaic devices.展开更多
Sandstone“injectite”intrusions are generally developed by the fluidization of weakly cemented sandstones and their subsequent injection into fractured reservoirs.In this work,a continuum coupled hydromechanical mode...Sandstone“injectite”intrusions are generally developed by the fluidization of weakly cemented sandstones and their subsequent injection into fractured reservoirs.In this work,a continuum coupled hydromechanical model TOUGH-FLAC3D is applied to simulate the discrete fracture network in large-scale sand injectite complexes.A sand production constitutive model is incorporated to consider the formation of sand through plastic deformation and its influence on evolution of fracture permeability.Overpressures in the fluidized sand slurry drives the injection with sand dikes intruded upwards,typically into previously low permeability“tight”mudstone formations.The contrast in poroelastic properties of the underlying weak sandstone and overlying injectite receptor directly affects the evolution of fracture aperture both during and after intrusion.Fluid drainage into the unconsolidated matrix may reduce the extent of fracture aperture growth,through the formation of shear bands.The results of this work have broad implications related to the emplacement of sandstone intrusions and subsequent hydrocarbon accumulation,maturation and then production.展开更多
Perovskite solar cells(PSCs)have undergone a dramatic increase in laboratory-scale effi ciency to more than 25%,which is comparable to Si-based single-junction solar cell effi ciency.However,the effi ciency of PSCs dr...Perovskite solar cells(PSCs)have undergone a dramatic increase in laboratory-scale effi ciency to more than 25%,which is comparable to Si-based single-junction solar cell effi ciency.However,the effi ciency of PSCs drops from laboratory-scale to large-scale perovskite solar modules(PSMs)because of the poor quality of perovskite fi lms,and the increased resistance of large-area PSMs obstructs practical PSC applications.An in-depth understanding of the fabricating processes is vital for precisely controlling the quality of large-area perovskite fi lms,and a suitable structural design for PSMs plays an impor-tant role in minimizing energy loss.In this review,we discuss several solution-based deposition techniques for large-area perovskite fi lms and the eff ects of operating conditions on the fi lms.Furthermore,diff erent structural designs for PSMs are presented,including the processing technologies and device architectures.展开更多
Coal seam CO2 sequestration is an important option to address global warming.A better knowledge on coal pore structure evolution during gas adsorption can provide guidance for coal seams CO2 seques-tration.However,few...Coal seam CO2 sequestration is an important option to address global warming.A better knowledge on coal pore structure evolution during gas adsorption can provide guidance for coal seams CO2 seques-tration.However,few investigations on the pore structure evolution differences between the deep and shallow coal were conducted during gas adsorption.In this study,based on the real-time synchrotron radiation small-angle X-ray scattering(SAXS)observation,the average pore diameter and pore surface fractal dimension evolution differences between deep and shallow coal were investigated from the as-pects of coal compositions and stress history.Two types of coal deformation(inner-swelling and outer-swelling)coexist during gas adsorption.Coal compositions have significant impact on the dominance of deformation type.The dominance of inner-swelling in deep coal is induced by the higher ash contents,and there is the decrease of average pore diameter during gas adsorption.The impact of stress-history(burial depth)on adsorption-induced deformation is more prominent than that of gas adsorption ca-pacity.In deep coal,the surface fractal dimension evolution presents a negative correlation with the evolution of pore diameters.In shallow coal,the surface fractal dimension evolution presents a Langmuir-type correlation with the adsorption time.展开更多
Bismuth vanadate(BiVO_(4))is a promising photoanode material for efficient photoelectrochemical(PEC)water splitting,whereas its performance is inhibited by detrimental surface states.To solve the problem,herein,a low-...Bismuth vanadate(BiVO_(4))is a promising photoanode material for efficient photoelectrochemical(PEC)water splitting,whereas its performance is inhibited by detrimental surface states.To solve the problem,herein,a low-cost organic molecule 1,3,5-benzenetricarboxylic acid(BTC)is selected for surface passivation of BiVO_(4) photoanodes(BVOs),which also provides bonding sites for Co^(2+)to anchor,resulting in a Co-BTC-BVO photoanode.Owing to its strong coordination with metal ions,BTC not only passivates surface states of BVO,but also provides bonding between BVO and catalytic active sites(Co^(2+))to form a molecular cocatalyst.Computational study and interfacial charge kinetic investigation reveal that chemical bonding formed at the interface greatly suppresses charge recombination and accelerates charge transfer.The obtained Co-BTC-BVO photoanode exhibits a photocurrent density of 4.82 mA/cm^(2) at 1.23 V vs.reversible hydrogen electrode(RHE)and a low onset potential of 0.22 VRHE under AM 1.5 G illumination,which ranks among the best photoanodes coupled with Co-based cocatalysts.This work presents a novel selection of passivation layers and emphasizes the significance of interfacial chemical bonding for the construction of efficient photoanodes.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52225402 and U1910206).
文摘Heat transfer and temperature evolution in overburden fracture and ground fissures are one of the essential topics for the identification of ground fissures via unmanned aerial vehicle(UAV) infrared imager. In this study, discrete element software UDEC was employed to investigate the overburden fracture field under different mining conditions. Multiphysics software COMSOL were employed to investigate heat transfer and temperature evolution of overburden fracture and ground fissures under the influence of mining condition, fissure depth, fissure width, and month alternation. The UAV infrared field measurements also provided a calibration for numerical simulation. The results showed that for ground fissures connected to underground goaf(Fissure Ⅰ), the temperature difference increased with larger mining height and shallow buried depth. In addition, Fissure Ⅰ located in the boundary of the goaf have a greater temperature difference and is easier to be identified than fissures located above the mining goaf. For ground fissures having no connection to underground goaf(Fissure Ⅱ), the heat transfer is affected by the internal resistance of the overlying strata fracture when the depth of Fissure Ⅱ is greater than10 m, the temperature of Fissure Ⅱ gradually equals to the ground temperature as the fissures’ depth increases, and the fissures are difficult to be identified. The identification effect is most obvious for fissures larger than 16 cm under the same depth. In spring and summer, UAV infrared identification of mining fissures should be carried out during nighttime. This study provides the basis for the optimal time and season for the UAV infrared identification of different types of mining ground fissures.
基金supported by the NSFC(21777096,21777097)the Ministry of Science and Technology of China(2018YFC1802001)+1 种基金the OU–SJTU strategic partnership development fundInternational Joint Research Promotion Program in Osaka University。
文摘Photoelectrochemical(PEC) technology provides a promising prospect for the transformation of polyethylene terephthalate(PET) plastic wastes to produce value-added chemicals.The PEC catalytic systems with high activity,selectivity and long-term durability are required for the future up-scaling industrial applications.Herein,we employed the interfacial modification strategy to develop an efficient and stable photoanode and evaluated its PEC activity for ethylene glycol(EG,derived from PET hydrolysate) oxidation to formic acid.The interfacial modification between Fe_(2)O_(3)semiconductor and Ni(OH)xcocatalyst with ultrathin TiO_(x) interlayer not only improved the photocurrent density by accelerating the kinetics of photogenerated charge carriers,but also kept the high Faradaic efficiency(over 95% in 30 h) towards the value-added formic acid product.This work proposes an effective method to promote the PEC activity and enhance the long-term stability of photoelectrodes for upcycling PET plastic wastes.
基金funded by the National Natural Science Foundation of China(No.81772595,81502459)Sun Yat-sen University Clinical Research 5010 Program(No.2015024,2013013)Science and Technology Planning Project of Guangdong Province(No.2013B021800146)
文摘Background: The prognostic nutritional index(PNI) has been widely applied for predicting survival outcomes of patients with various malignant tumors. Although a low PNI predicts poor prognosis in patients with colorectal cancer after tumor resection, the prognostic value remains unknown in patients with stage Ⅲ colon cancer undergoing curative tumor resection followed by adjuvant chemotherapy. This study aimed to investigate the prognostic value of PNI in patients with stage III colon cancer.Methods: Medical records of 274 consecutive patients with stage Ⅲ colon cancer undergoing curative tumor resection followed by adjuvant chemotherapy with oxaliplatin and capecitabine between December 2007 and December2013 were reviewed. The optimal PNI cutoff value was determined using receiver operating characteristic(ROC) curve analysis. The associations of PNI with systemic inflammatory response markers, including lymphocyte-to-monocyte ratio(LMR), neutrophil-to-lymphocyte ratio(NLR), platelet-to-lymphocyte ratio(PLR), and C-reactive protein(CRP)level, and clinicopathologic characteristics were assessed using the Chi square or Fisher's exact test. Correlation analysis was performed using Spearman's correlation coefficient. Disease-free survival(DFS) and overall survival(OS)stratified by PNI were analyzed using Kaplan-Meier method and log-rank test, and prognostic factors were identified by Cox regression analyses.Results: The preoperative PNI was positively correlated with LMR(r= 0.483, P < 0.001) and negatively correlated with NLR(r =-0.441, P < 0.001), PLR(r =-0.607, P < 0.001), and CRP level(r =-0.333, P < 0.001). A low PNI(≤49.22)was significantly associated with short OS and DFS in patients with stage ⅢC colon cancer but not in patients with stage ⅢA/ⅢB colon cancer.In addition, patients with a low PNI achieved a longer OS and DFS after being treated with6-8 cycles of adjuvant chemotherapy than did those with < 6 cycles. Multivariate analyses revealed that PNI was independently associated with DFS(hazard ratios 2.001; 95% confidence interval 1.157-3.462; P = 0.013).Conclusion: The present study identified preoperative PNI as a valuable predictor for survival outcomes in patients with stage Ⅲ colon cancer receiving curative tumor resection followed by adjuvant chemotherapy.
基金supported by the National Natural Science Foundation of China(No.51804309)the Yue Qi Young Scholar Project(2019QN02)+5 种基金Distinguished Scholar Project(2017JCB02)from China University of Mining and Technology-Beijing,Open Fund of State Key Laboratory of Water Resource Protection and Utilization in Coal Mining(Grant No.SHJT-17-42.10)National Natural Science Foundation of China(No.U1910206)the fund of Beijing Outstanding Young Scientist Program(BJJWZYJH01201911413037)the State Key Laboratory of Coal Resources and Safe Mining(Nos.SKLCRSM16KFB07,SKLCRSM16DCB01 and SKLCRSM17DC11)Young Elite Scientists Sponsorship Program by CAST(2017QNRC001)the key project of Key Laboratory of Coal Mine Safety and High Efficiency Mining Co-established by the Province and the Ministry(Anhui University of Science and Technology)(No.JYBSYS2018201).
文摘The fracture behaviour and crack propagation features of coal under coupled static-dynamic loading conditions are important when evaluating the dynamic failure of coal.In this study,coupled static-dynamic loading tests are conducted on Brazilian disc(BD)coal specimens using a modified split Hopkinson pressure bar(SHPB).The effects of the static axial pre-stress and loading rate on the dynamic tensile strength and crack propagation characteristics of BD coal specimens are studied.The average dynamic indirect tensile strength of coal specimens increases first and then decreases with the static axial pre-stress increasing.When no static axial pre-stress is applied,or the static axial pre-stress is 30%of the static tensile strength,the dynamic indirect tensile strength of coal specimens shows an increase trend as the loading rate increases.When the static axial pre-stress is 60%of the static tensile strength,the dynamic indirect tensile strength shows a fluctuant trend as the loading rate increases.According to the crack propagation process of coal specimens recorded by high-speed camera,the impact velocity influences the mode of crack propagation,while the static axial pre-stress influences the direction of crack propagation.The failure of coal specimens is a coupled tensile-shear failure under high impact velocity.When there is no static axial pre-stress,tensile cracks occur in the vertical loading direction.When the static axial pre-stress is applied,the number of cracks perpendicular to the loading direction decreases,and more cracks occur in the parallel loading direction.
基金supported by the National Key Research and Development Program (Grant No. 2016YFC0801401)National Natural Science Foundation of China (Grant No. 41502184)Beijing Natural Science Foundation (Grant No. 2164067)
文摘Coal bump refers to a sudden catastrophic failure of coal seam and usually can cause serious damages to underground mining facilities and staff. In this circumstance, this paper focuses on the recent achievements in the mechanism and prevention techniques of coal bumps over the past five years in China.Based on theoretical analysis, laboratory experiment, numerical simulation and field test, the characteristics of coal bumps occurrence in China's coal mines were described, and the difference between coal bumps and rockbursts was also discussed. In addition, three categories of coal bumps induced by"material failure" were introduced, i.e. hard roof, floor strata and tectonic structures, in which the mechanism of coal bumps induced by geological structures was analyzed. This involves the bump liability and microstructure effects on bump-prone coal failure, the mechanism of coal bumps in response to fault reactivation, island face mining or hard roof failure. Next, the achievements in the monitoring and controlling methods of coal bumps were reviewed. These methods involve the incorporated prediction system of micro-seismicity and mining-induced pressure, the distributed micro-seismic monitoring system, energy absorption support system, bolts with constant resistance and large elongation,and the "multi-stage" high-performance support. Finally, an optimal mining design is desirable for the purpose of coal bump mitigation.
基金financially supported by National Science and Technology Key Project Fund of China (Nos.2016YFC0801401 and 2016YFC0600708)Fundamental Research Funds for the Central Universities of China (No.2009QM01)Yue Qi Distinguished Scholar Project,China University of Mining & Technology,Beijing,China
文摘Irregular shape workface would result in the presence of coal pillar, which leads to high stress concentration and possibly induces coal bumps. In order to study the coal bump mechanism of pillars, static and dynamic stress overlapping(SDSO) method was proposed to explain the impacts of static stress concentration and tremors induced by mining activities. The stress and deformation in surrounding rock of mining face were analyzed based on the field case study at 1303 workface in Zhaolou Coal Mine in China.The results illustrate that the surrounding rock of a workface could be divided into four different zones,i.e., residual stress zone, stress decrease zone, stress increase zone and original stress zone. The stress increase zone is prone to failure under the SDSO impact loading conditions and will provide elastic energy for inducing coal bump. Based on the numerical modelling results, the evolution of static stress in coal pillar as the size of gob increasing was studied, and the impact of dynamic stress was investigated through analyzing the characteristics of tremor activities. The numerical results demonstrate the peak value of vertical stress in coal pillar rises from about 30 MPa with mining distance 10 m to 52.6 MPa with mining distance 120 m, and the location of peak stress transfers to the inner zone of coal pillars as the workface moves forward. For the daily tremor activities, tremors with high energy released indicate high dynamic stress disturbance on the surrounding rock, therefore, the impact of dynamic stressing is more serious during workface extension period because the tremor frequency and average energy after workface extension are higher than those before the workface extension.
基金supported by the Natural Science Foundation of Anhui province and Jiangxi province(JZ2018AKZR0058,20202BAB204007)the Fundamental Research Funds for the Central Universities(PA2020GDGP0054)the National Natural Science Foundation of China(U1832136 and 21303038)。
文摘Lithium-sulfur(Li-S)batteries have great potential in next-generation energy storage due to its high theoretical specific capacity and energy density.However,there are several challenges to the practical application of Li-S batteries including the growth of lithium dendrites and the shuttle effect of polysulfide.Introducing interlayeres(freestanding or coated on the separator)is an effective approach to reduce these obstacles and improve the electrochemical performance of Li-S batteries.In this review,we briefly summarize the interlayer materials and structures modified on both cathodic and anodic sides including(ⅰ)carbon-based materials,(ⅱ)polymers,(ⅲ)inorganic metal compounds,(iv)metal-organic frameworks,as well as(v)the novel separators in recent years.We also systematically address the fabrication processes,assembling methods,and functions of interlayers for enhancing the performance of Li-S batteries.Furthermore,the prospects and outlooks of the future development of advanced interlayers and separators are also presented.
基金the support of the NSFC (Grant 21777096 and 51861145101)Huoyingdong Grant (151046)+1 种基金the support of the Initiative Postdocs Supporting Program (Grant No.BX20180185)China Postdoctoral Science Foundation (Grant No.2018M640387)。
文摘Surface passivation via post-treatment with organic reagents is a popular strategy to improve the stability and efficiency of perovskite solar cell. However, organic passivation still suffers from the weak bonding between organic chemicals and perovskite layers. Here we reported a facile inorganic layer passivating method containing strong Pb–S bonding by using ammonium sulfide treatment. A compact PbS_x layer was in-situ formed on the top surface of the perovskite film, which could passivate and protect the perovskite surface to enhance the performance and stability. Our novel inorganic passivation layer strategy demonstrates great potential for the development of high efficiency hybrid and robust perovskite optoelectronics.
基金This work was supported by the National Natural Science Foundation of China(Nos.U1910206,51874312,51861145403)Science and Technology Project of Inner Mongolia Autonomous Region(No.2019GG140)Major Scientific and Technological Innovation Project of Shandong Province(Nos.2019SDZY01,2019SDZY02).These sources of supports are gratefully acknowledged.
文摘As coal mining is extended from shallow to deep areas along the western coalfield,it is of great significance to study weakly cemented sandstone at different depths for underground mining engineering.Sandstones from depths of 101.5,203.2,317.3,406.9,509.9 and 589.8 m at the Buertai Coal Mine were collected.The characteristic strength,acoustic emission(AE),and energy evolution of sandstone during uniaxial compression tests were analyzed.The results show that the intermediate frequency(125-275 kHz)of shallow rock mainly occurs in the postpeak stage,while deep rock occurs in the prepeak stage.The initiation strength and damage strength of the sandstone at different depths range from 0.23 to 0.50 and 0.63 to 0.84 of peak strength(σ_(c)),respectively,decrease exponentially and are a power function with depth.The precursor strength ranges from 0.88σ_(c)to 0.99σ_(c),increases with depth before reaching a depth of 300 m,and tends to stabilize after 300 m.The ratio of the initiation strength to the damage strength(k)ranges from 0.25 to 0.62 and decreases exponentially with depth.The failure modes of sandstone at different depths are tension-dominated mixed tensile-shear failure.Shear failure mainly occurs at the unstable crack propagation stage.The count of the shear failure bands before the peak strength increases gradually,and increases first and then decreases after the peak strength with burial depth.The cumulative input energy,released elastic energy and dissipated energy increase with depth.The elastic release rate ranges from 0.46×10^(-3)to 198.57×10^(-3)J/(cm^(3)s)and increases exponentially with depth.
基金supported by the NSFC(Grant 51861145101,21777096)Huoyingdong Grant(151046)+1 种基金Shanghai Shuguang Grant(17SG11)the China Postdoctoral Science Foundation(2017M621466)
文摘The organic–inorganic hybrid perovskite solar cells(PSCs)have demonstrated their unprecedented high efficiency and potential for commercialization.The volatile organic components in the hybrid perovskite crystal structure are still a big challenge for long-term stabilities.Recently,inorganic CsPbI3 perovskite has attracted much attention because of its superior chemical stability over the prevailing hybrid organic–inorganic perovskite and the most suitable band gap among all-inorganic perovskites.Nevertheless,CsPbI3 suffers from phase instability and low photovoltaic(PV)performance due to its undesirable tolerant factor.Much research effort has been devoted into stabilization of CsPbI3.In this perspective,we review the recent progress on chemical engineering processes for the stabilization of inorganic CsPbI3 perovskite for high-efficiency PVs.We also discuss the importance of understanding mechanism behind stabilization of CsPbI3 perovskite film and the development of inorganic CsPbI3-based highly efficient and stable PSCs.
基金the support of the NSFC(Grant 51372151 and21303103)Huoyingdong Grant(151046)
文摘The mixed-cation lead halide perovskites have emerged as a new class of promising light harvesting materials for solar cells. The formamidinium(FA), methylammonium(MA) and Cs cations are widely studied in the field of mixed-cation perovskites. Here, we have investigated ethylammonium(EA) as an alternative cation to fabricate a mixed-cation perovskite of MA_(1-x)EA_xPbI_3. We have characterized the materials using the X-ray diffraction(XRD), scanning electron microscope(SEM), and UV–vis spectrum. Our results have confirmed the successful incorporation of EA cations into MAPbI_3. Interestingly, the optimal amount of EA to achieve the best performance is quite low. This is different from the FA–MA mixed-cation perovskites although EA and FA have similar radii. In short, the EA–MA mixed-cation perovskite has some material and device properties highly distinguishable from the FA–MA one.
基金supported by the Fundamental Research Funds for the Central Universities(2020XJNY03)the YueQi Distinguished Scholar Project of China University of Mining&Technology,Beijing。
文摘In the enhanced geothermal system(EGS),the injected fluid will induce shear sliding of rock fractures(i.e.,hydroshearing),which consequently,would increase the fracture aperture and improve the heat transfer efficiency of the geothermal reservoir.In this study,theoretical analysis,experimental research and numerical simulation were performed to uncover the permeability and heat transfer enhancement mechanism of the Hot-Dry-Rock(HDR)mass under the impact of shearing.By conducting the direct shear test with the fractured rock samples,the evolution process of fracture aperture during the shearing tests was observed,during which process,cubic law was adopted to depict the rock fracture permeability.To investigate the seepage characteristics and temperature distribution of the fractured HDR under the influence of shearing,a simulation study of shear-seepage-heat transfer in a fractured rock mass has been conducted to validate the observed shear-induced fracture dilation during the direct shear test.The results demonstrate that(1)the hydroshearing increases the dilation of granite fracture and enhances the permeability of the HDR rock mass,while the temperature around the HDR fracture will reduce.(2)Fracture roughness is of vital importance to enhance the permeability during the shearing tests.To be more specific,a rougher fracture always implies a higher permeability and a greater heat extraction efficiency.(3)The shear induced heat extracting efficiency is dominated by the increased fluid flux in the earlier period of the EGS reservoir,and this efficiency is controlled by the outlet water temperature since the fluid flux becomes stable after the shearing test.Therefore,balancing the hydroshearing enhanced heat extraction efficiency and EGS reservoir lifespan would be significant to the sustainable development and utilization of geothermal energy.
基金support from the National Natural Science Foundation of China (Grant Nos. 22025505, 51861145101,21777096)the Program of Shanghai Academic/Technology Research Leader (Grant No. 20XD1422200)+1 种基金the Key Laboratory of Resource Chemistry,Ministry of Education (Grant No.KLRC_ME2003)support from the Energy Materials and Surface Sciences Unit of the Okinawa Institute of Science and Technology Graduate University。
文摘Cesium lead iodide(CsPbI_(3)) perovskite has gained great attention in the photovoltaic(PV) community because of its unique optoelectronic properties, good chemical stability and appropriate bandgap for sunlight harvesting applications. However, compared to solar cells fabricated from organic-inorganic hybrid perovskites, the commercialization of devices based on all-inorganic CsPbI_(3) perovskites still faces many challenges regarding PV performance and long-term stability. In this work, we discovered that tetrabutylammonium bromide(TBABr) post-treatment to CsPbI_(3) perovskite films could achieve synergistic stabilization with both TBA+cation intercalation and Br-doping. Such TBA^(+) cation intercalation leads to onedimensional capping with TBAPb I3 perovskite formed in situ, while the Br-induced crystal secondary growth helps effectively passivate the defects of CsPbI_(3) perovskite, thus enhancing the stability. In addition, the incorporation of TBABr can improve energy-level alignment and reduce interfacial charge recombination loss for better device performance. Finally, the highly stable TBABr-treated CsPbI_(3)-based perovskite solar cells show reproducible photovoltaic performance with a champion efficiency up to 19.04%, while retaining 90% of the initial efficiency after 500 h storage without encapsulation.
基金supported by the National Key Research and Development Program of China(2017YFE0127100)the National Natural Science Foundation of China(NSFC,Grant 22025505)+1 种基金the Program of Shanghai Academic Technology Research Leader(Grant 20XD1422200)the Key Laboratory of Resource Chemistry,Ministry of Education(KLRC_ME2003)。
文摘FA-Cs mixed-cation perovskite has been reported as a promising candidate for obtaining highly efficient and stable photovoltaic devices.Phenylethylamine iodide(PEAI)post-treatment is a widely used and effective method for surface passivation of FA-Cs perovskite layer in devices.However,it is still controversial whether the PEAI post-treatment would form two-dimensional(2D)perovskite PEA_(2)PbI_(4) capping layer or just result in PEA+terminated surface.Here in this work,the function of PEAI post-treatment on FA-Cs mixed-cation perovskite FA_(1-x)Cs_(x)PbI_(3)(x=0.1–0.9)with varied Cs contents is elucidated.With increased Cs content,the FA-Cs perovskite shows higher resistance to the cation exchange between FA+and PEA+.This Cs-content-dependent cation exchange results in the different PEAI reaction preferences with FA-Cs mixed-cation perovskites.Furthermore,higher Cs content with stronger resistance to cation exchange reaction leads to a wider processing window for post-treatment and defect passivation,which is beneficial for the fabrication of large-scale photovoltaic devices.
基金the financial support from the Laboratory of Coal Resources and Safe Mining(China University of Mining and Technology,Beijing)(Grant No.SKLCRSM16KFC01)。
文摘Sandstone“injectite”intrusions are generally developed by the fluidization of weakly cemented sandstones and their subsequent injection into fractured reservoirs.In this work,a continuum coupled hydromechanical model TOUGH-FLAC3D is applied to simulate the discrete fracture network in large-scale sand injectite complexes.A sand production constitutive model is incorporated to consider the formation of sand through plastic deformation and its influence on evolution of fracture permeability.Overpressures in the fluidized sand slurry drives the injection with sand dikes intruded upwards,typically into previously low permeability“tight”mudstone formations.The contrast in poroelastic properties of the underlying weak sandstone and overlying injectite receptor directly affects the evolution of fracture aperture both during and after intrusion.Fluid drainage into the unconsolidated matrix may reduce the extent of fracture aperture growth,through the formation of shear bands.The results of this work have broad implications related to the emplacement of sandstone intrusions and subsequent hydrocarbon accumulation,maturation and then production.
基金supported by the National Key Research and Development Program of China(No.2017YFE0127100)the National Natural Science Foundation of China(No.22025505)the Program of Shanghai Academic/Technology Research Leader(No.20XD1422200).
文摘Perovskite solar cells(PSCs)have undergone a dramatic increase in laboratory-scale effi ciency to more than 25%,which is comparable to Si-based single-junction solar cell effi ciency.However,the effi ciency of PSCs drops from laboratory-scale to large-scale perovskite solar modules(PSMs)because of the poor quality of perovskite fi lms,and the increased resistance of large-area PSMs obstructs practical PSC applications.An in-depth understanding of the fabricating processes is vital for precisely controlling the quality of large-area perovskite fi lms,and a suitable structural design for PSMs plays an impor-tant role in minimizing energy loss.In this review,we discuss several solution-based deposition techniques for large-area perovskite fi lms and the eff ects of operating conditions on the fi lms.Furthermore,diff erent structural designs for PSMs are presented,including the processing technologies and device architectures.
基金supported by the National Natural Science Foundation of China (grant Nos.U1910206,52004293,52225402)Beijing Natural Science Foundation (grant No.8232057)+4 种基金the Open Project Program of State Key Laboratory of Coal and CBM Co-mining (grant No.2022KF21)Fundamental Research Funds for the Central Universities (grant No.FRF-TP-20-034A1)the Open Project Program of Key Laboratory of Deep Earth Science and Engineering (Sichuan University)Ministry of Education (grant No.DESE 202004)China Postdoctoral Science Foundation (grant No.2018M641526).
文摘Coal seam CO2 sequestration is an important option to address global warming.A better knowledge on coal pore structure evolution during gas adsorption can provide guidance for coal seams CO2 seques-tration.However,few investigations on the pore structure evolution differences between the deep and shallow coal were conducted during gas adsorption.In this study,based on the real-time synchrotron radiation small-angle X-ray scattering(SAXS)observation,the average pore diameter and pore surface fractal dimension evolution differences between deep and shallow coal were investigated from the as-pects of coal compositions and stress history.Two types of coal deformation(inner-swelling and outer-swelling)coexist during gas adsorption.Coal compositions have significant impact on the dominance of deformation type.The dominance of inner-swelling in deep coal is induced by the higher ash contents,and there is the decrease of average pore diameter during gas adsorption.The impact of stress-history(burial depth)on adsorption-induced deformation is more prominent than that of gas adsorption ca-pacity.In deep coal,the surface fractal dimension evolution presents a negative correlation with the evolution of pore diameters.In shallow coal,the surface fractal dimension evolution presents a Langmuir-type correlation with the adsorption time.
基金support from the National Natural Science Foundation of China(No.51672173,U1733130)Shanghai Science and Technology Committee(Nos.21ZR1435700,18520744700, 18JC1410500)Shanghai Jiao Tong University Medical Engineering Cross Research Program(No.YG2023ZD18).
文摘Bismuth vanadate(BiVO_(4))is a promising photoanode material for efficient photoelectrochemical(PEC)water splitting,whereas its performance is inhibited by detrimental surface states.To solve the problem,herein,a low-cost organic molecule 1,3,5-benzenetricarboxylic acid(BTC)is selected for surface passivation of BiVO_(4) photoanodes(BVOs),which also provides bonding sites for Co^(2+)to anchor,resulting in a Co-BTC-BVO photoanode.Owing to its strong coordination with metal ions,BTC not only passivates surface states of BVO,but also provides bonding between BVO and catalytic active sites(Co^(2+))to form a molecular cocatalyst.Computational study and interfacial charge kinetic investigation reveal that chemical bonding formed at the interface greatly suppresses charge recombination and accelerates charge transfer.The obtained Co-BTC-BVO photoanode exhibits a photocurrent density of 4.82 mA/cm^(2) at 1.23 V vs.reversible hydrogen electrode(RHE)and a low onset potential of 0.22 VRHE under AM 1.5 G illumination,which ranks among the best photoanodes coupled with Co-based cocatalysts.This work presents a novel selection of passivation layers and emphasizes the significance of interfacial chemical bonding for the construction of efficient photoanodes.
