The metal promoted In_(2)O_(3) catalysts for CO_(2) hydrogenation to methanol have attracted wide attention because of their high activity with high methanol selectivity.However,there was still no experimental confirm...The metal promoted In_(2)O_(3) catalysts for CO_(2) hydrogenation to methanol have attracted wide attention because of their high activity with high methanol selectivity.However,there was still no experimental confirmation if copper could be a good promoter for In_(2)O_(3).Herein,the Cu promoted In_(2)O_(3) catalyst was prepared using a deposition-precipitation method.Such prepared Cu/In_(2)O_(3) catalyst shows significantly higher CO_(2) conversion and space time yield(STY)of methanol,compared to the un-promoted In_(2)O_(3) catalyst.The loading of Cu facilitates the activation of both H_(2) and CO_(2) with the interface between the Cu cluster and defective In_(2)O_(3) as the active site.The Cu/In_(2)O_(3) catalyst takes the CO hydrogenation pathway for methanol synthesis from CO_(2) hydrogenation.It exhibits a unique size effect on the CO adsorption.At temperatures below 250℃,CO adsorption on Cu/In_(2)O_(3) is stronger than that on In_(2)O_(3),causing higher methanol selectivity.With increasing temperatu res,the Cu catalyst aggregates,which leads to the formation of weak CO adsorption site and causes a decrease in the methanol selectivity.Compared with other metal promoted In_(2)O_(3) catalysts,it can be concluded that the catalyst with stronger CO adsorption possesses higher methanol selectivity.展开更多
Malocclusion,identified by the World Health Organization(WHO)as one of three major oral diseases,profoundly impacts the dental-maxillofacial functions,facial esthetics,and long-term development of~260 million children...Malocclusion,identified by the World Health Organization(WHO)as one of three major oral diseases,profoundly impacts the dental-maxillofacial functions,facial esthetics,and long-term development of~260 million children in China.Beyond its physical manifestations,malocclusion also significantly influences the psycho-social well-being of these children.Timely intervention in malocclusion can foster an environment conducive to dental-maxillofacial development and substantially decrease the incidence of malocclusion or reduce the severity and complexity of malocclusion in the permanent dentition,by mitigating the negative impact of abnormal environmental influences on the growth.Early orthodontic treatment encompasses accurate identification and treatment of dental and maxillofacial morphological and functional abnormalities during various stages of dental-maxillofacial development,ranging from fetal stages to the early permanent dentition phase.From an economic and societal standpoint,the urgency for effective early orthodontic treatments for malocclusions in childhood cannot be overstated,underlining its profound practical and social importance.This consensus paper discusses the characteristics and the detrimental effects of malocclusion in children,emphasizing critical need for early treatment.It elaborates on corresponding core principles and fundamental approaches in early orthodontics,proposing comprehensive guidance for preventive and interceptive orthodontic treatment,serving as a reference for clinicians engaged in early orthodontic treatment.展开更多
For the recycling of Pd and Ag from high-level liquid waste(HLLW), the electrochemical behaviors of Pd and Ag in the simulated HNO_(3) solutions were investigated by cyclic voltammetry and potentiostatic deposition.Sc...For the recycling of Pd and Ag from high-level liquid waste(HLLW), the electrochemical behaviors of Pd and Ag in the simulated HNO_(3) solutions were investigated by cyclic voltammetry and potentiostatic deposition.Scanning electron microscopy(SEM) and X-ray diffraction(XRD) were used to-observe the deposits morphology and to evaluate their composition. The results indicate that the formation of NO_(2)^(-)electrodeposited. When Pd and Ag are electrodeposited together, more metals are gained in the same time, and the deposited Ag does not dissolve in this situation. The metals are electrodeposited completely at the potentials from -0.4 to -0.6 V(vs MSE) and the deposits contai-n Ag and PdHx. The electrodeposition of Pd can boost h-ydrogen evolution,and then the reaction between H;and NO_(2)^(-)is sped up, thereby lowering the concentration of NO_(2)^(-)and inhibiting the dissolution of Ag.展开更多
·AIM:To evaluate optic nerve head(ONH)vessel density(VD)changes after cataract surgery using optical coherence tomography angiography(OCTA).·METHODS:This was a prospective observational study.Thirty-four eye...·AIM:To evaluate optic nerve head(ONH)vessel density(VD)changes after cataract surgery using optical coherence tomography angiography(OCTA).·METHODS:This was a prospective observational study.Thirty-four eyes with mild/moderate cataracts were included.ONH scans were obtained before and 3mo after cataract surgery using OCTA.Radial peripapillary capillary(RPC)density,all VD,large VD and retinal nerve fiber layer thickness(RNFLT)in total disc,inside disc,and different peripapillary sectors were assessed and analyzed.Image quality score(QS),fundus photography grading and bestcorrected visual acuity(BCVA)were also collected,and correlation analyses were performed between VD change and these parameters.·RESULTS:Compared with baseline,both RPC and all VD increased in inside disc area 3mo postoperatively(from 47.5%±5.3%to 50.2%±3.7%,and from 57.87%±4.30%to 60.47%±3.10%,all P<0.001),but no differences were observed in peripapillary area.However,large VD increased from 5.63%±0.77%to 6.47%±0.72%in peripapillary ONH region(P<0.001).RPC decreased in inferior and superior peripapillary ONH parts(P=0.019,<0.001 respectively).There were obvious negative correlations between RPC change and large VD change in inside disc,superior-hemi,and inferior-hemi(r=-0.419,-0.370,and-0.439,P=0.017,0.044,and 0.015,respectively).No correlations were found between VD change and other parameters including QS change,fundus photography grading,postoperative BCVA,and postoperative peripapillary RNFLT.·CONCLUSION:RPC density and all VD in the inside disc ONH region increase 3mo after surgery in patients with mild to moderate cataract.No obvious VD changes are found in peripapillary area postoperatively.展开更多
Previous experimental and computational results have confirmed that the thermal conductivity of a twodimensional(2D) material can be considerably affected by strain. Numerous attention has been paid to explore the rel...Previous experimental and computational results have confirmed that the thermal conductivity of a twodimensional(2D) material can be considerably affected by strain. Numerous attention has been paid to explore the relevant mechanisms. However, the strain effects on the interfacial thermal conductance(ITC) of 2D heterostructure have attracted little attention. Herein, the non-equilibrium molecular dynamics(NEMD) simulations were conducted to the graphene/hexagonal boron nitride(GR/h-BN) heterostructure to investigate the strain effects on the ITC. Three types of strains were considered, i.e., tensile strain, compressive strain, and shear strain.The results indicate that the strain can adjust the ITC for the GR/h-BN heterostructure effectively, and the strain loading direction also influences the ITC. Generally, the tensile strain reduces the ITC of the heterostructure, in addition to the BN-C system at small tensile strain;both the compressive strain and shear strain increase the ITC,especially at a small strain. For the NB-C system, it is more sensitive to the strain loading direction and the yx shear strain of 0.06 is the most effective way to strengthen the ITC. Our results also show that the out-of-plane deformation weakens the in-plane vibration of atoms, leading to a reduction of the interfacial thermal energy transport.展开更多
In this study,Qilian Mountain active source airgun signals recorded at 79 stations were obtained after stacking waveforms from July 2015 to December 2016.Based on analysis of the amplitude variation characteristics of...In this study,Qilian Mountain active source airgun signals recorded at 79 stations were obtained after stacking waveforms from July 2015 to December 2016.Based on analysis of the amplitude variation characteristics of the airgun signals,the following conclusions were drawn:along the NW-SE fault distribution direction of the Qilian Mountain area,the decrease in amplitude of airgun signals was relatively slow in relation to the epicentral distance,while the decrease in amplitude in the direction perpendicular to the fault was relatively fast.This difference may be related to the energy loss of seismic waves reflecting and scattering by the regional faults mainly distributed along the NW-SE direction,which are caused by tectonic compression of the QinghaiTibet and Alxa blocks.展开更多
Water diversion is a common strategy to enhance water quality in eutrophic lakes by increasing available water resources and accelerating nutrient circulation.Its effectiveness depends on changes in the source water a...Water diversion is a common strategy to enhance water quality in eutrophic lakes by increasing available water resources and accelerating nutrient circulation.Its effectiveness depends on changes in the source water and lake conditions.However,the challenge of optimizing water diversion remains because it is difficult to simultaneously improve lake water quality and minimize the amount of diverted water.Here,we propose a new approach called dynamic water diversion optimization(DWDO),which combines a comprehensive water quality model with a deep reinforcement learning algorithm.We applied DWDO to a region of Lake Dianchi,the largest eutrophic freshwater lake in China and validated it.Our results demonstrate that DWDO significantly reduced total nitrogen and total phosphorus concentrations in the lake by 7%and 6%,respectively,compared to previous operations.Additionally,annual water diversion decreased by an impressive 75%.Through interpretable machine learning,we identified the impact of meteorological indicators and the water quality of both the source water and the lake on optimal water diversion.We found that a single input variable could either increase or decrease water diversion,depending on its specific value,while multiple factors collectively influenced real-time adjustment of water diversion.Moreover,using well-designed hyperparameters,DWDO proved robust under different uncertainties in model parameters.The training time of the model is theoretically shorter than traditional simulation-optimization algorithms,highlighting its potential to support more effective decisionmaking in water quality management.展开更多
Lake Fuxian is the largest deep freshwater lake in China. Although its average water quality meets Class I of the China National Water Quality Standard (CNWQS), i.e., GB3838-2002, monitoring data indicate that the w...Lake Fuxian is the largest deep freshwater lake in China. Although its average water quality meets Class I of the China National Water Quality Standard (CNWQS), i.e., GB3838-2002, monitoring data indicate that the water quality approaches the Class II threshold in some areas. Thus it is urgent to reduce the watershed load through the total maximum daily load (TMDL) program. A three-dimensional hydrodynamic and water quality model was developed for Lake Fuxian, simulating flow circulation and pollutant fate and transport. The model development process consists of several steps, including grid generation, initial and boundary condition configurations, and model calibration processes. The model accurately reproduced the observed water surface elevation, spatiotemporal variations in temperature, and total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) concentrations, suggesting a reasonable numerical representation of the prototype system for further TMDL analyses. The TMDL was calculated using two interpretations of the water quality standards for Class I of the CNWQS based on the maximum instantaneous surface and annual average surface water concentrations. Analysis of the first scenario indicated that the TN, TP and COD loads should be reduced by 66%, 68% and 57%, respectively. Water quality was the highest priority; however, local economic development and cost feasibility for load reduction can pose significant issues. In the second interpretation, the model results showed that, under the existing conditions, the average water quality meets the Class I standard and therefore load reduction is unnecessary. Future studies are needed to conduct risk and cost assessments for realistic decision-making.展开更多
Near-infrared (NIR) persistent-luminescence nanoparticles have emerged as a new class of background-free contrast agents that are promising for in vivo imaging. The next key roadblock is to establish a robust and co...Near-infrared (NIR) persistent-luminescence nanoparticles have emerged as a new class of background-free contrast agents that are promising for in vivo imaging. The next key roadblock is to establish a robust and controllable method for synthesizing monodisperse nanoparticles with high luminescence brightness and long persistent duration. Herein, we report a synthesis strategy involving the coating/etching of the SiO2 shell to obtain a new class of small NIR highly persistent luminescent ZnGa2O4:Cr^3+,Sn^4+(ZGOCS) nanoparticles. The optimized ZGOCS nanoparticles have an excellent size distribution of -15 nm without any agglomeration and an NIR persistent luminescence that is enhanced by a factor of 13.5, owing to the key role of the SiO2 shell in preventing nanoparticle agglomeration after annealing. The ZGOCS nanoparticles have a signal-to-noise ratio -3 times higher than that of previously reported ZnGa204:Cr^3+ (ZGC-1) nanoparticles as an NIR persistent-luminescence probe for in vivo bioimaging. Moreover, the persistent-luminescence signal from the ZGOCS nanoparticles can be repeatedly re-charged in situ with external excitation by a white light- emitting diode; thus, the nanopartides are suitable for long-term in vivo imaging applications. Our study suggests an improved strategy for fabricating novel high-performance optical nanoparticles with good biocompatibility.展开更多
Recently,metal–organic frameworks(MOFs)have received considerable attention as highly efficient adsorbents for dye wastewater remediation.However,the immobilization of MOFs on the substrate surfaces to fabricate easy...Recently,metal–organic frameworks(MOFs)have received considerable attention as highly efficient adsorbents for dye wastewater remediation.However,the immobilization of MOFs on the substrate surfaces to fabricate easy recy-clable adsorbents via a facile route is still a challenge.In this work,ZIF-67/cotton fibers as adsorbents for dye removal were prepared in a large-scale using a simple coordination replication method.The successful fabrication of the ZIF-67/cotton fibers was confirmed by FTIR,XRD,XPS,SEM and BET analysis,respectively.As expected,the as-prepared ZIF-67/cotton fibers exhibited high adsorption capacity of 3787 mg/g towards malachite green(MG).Meanwhile,the adsorption kinetics and isotherm obeyed the pseudo-second-order kinetics and Langmuir model,respectively.Moreover,its removal efficiency towards MG was not significantly influenced by the pH and ionic strength of aque-ous solution.Most importantly,the ZIF-67/cotton fibers can remove MG from synthetic effluents,and it can be easily regenerated without filtration or centrifugation processes,with the regeneration efficiency remaining over 90%even after 10 cycles.Additionally,the ZIF-67/cotton fibers presented excellent antimicrobial performance against E.coli and S.aureus.Hence,the distinctive features of the as-prepared ZIF-67/cotton fibers make it promisingly applicable for the colored wastewater treatment.展开更多
To enhance the effectiveness of watershed load reduction decision making, the Risk Explicit Interval Linear Programming (REILP) approach was developed in previous studies to address decision risks and system returns...To enhance the effectiveness of watershed load reduction decision making, the Risk Explicit Interval Linear Programming (REILP) approach was developed in previous studies to address decision risks and system returns. However, REILP lacks the capability to analyze the tradeoff between risks in the objective function and constraints. Therefore, a refined REILP model is proposed in this study to further enhance the decision support capability of the REILP approach for optimal watershed load reduction. By introducing a tradeofffactor (α) into the total risk function, the refined REILP can lead to different compromises between risks associated with the objective functions and the constraints. The proposed model was illustrated using a case study that deals with uncertainty- based optimal load reduction decision making for Lake Qionghai Watershed, China. A risk tradeoff curve with different values of a was presented to decision makers as a more flexible platform to support decision formulation. The results of the standard and refined REILP model were compared under 11 aspiration levels. The results demon- strate that, by applying the refined REILP, it is possible to obtain solutions that preserve the same constraint risk as that in the standard REILP but with lower objective risk, which can provide more effective guidance for decision makers.展开更多
Background:Type 2 Peters ano maly is a rare anted or segment disorder characterized by central corneal leukoma with keratolenticular adhesion and cataract.Performing cataract surgery without corneal tissue transplanta...Background:Type 2 Peters ano maly is a rare anted or segment disorder characterized by central corneal leukoma with keratolenticular adhesion and cataract.Performing cataract surgery without corneal tissue transplantation in patients of type 2 Peters anomaly is extremely rare and challenging.We present a case of type 2 Peters anomaly treated by peeling off the adhesion without penetrating keratoplasty(PKP),in which restoration of corneal transparency is observed.Case presentation:An 11-month-old female infant of type 2 Peters anomaly presented with bilateral corneal opacity with distinct demarcation,keratolenticular adhesion and cataract,which was first noted at the age of 3 months.By peeling off the adhesion from comeal endothelium combined with lensectomy and vitrectomy,there was a gradual reduction in corneal opacity and improvement in visual acuity after surgery over a 2-year period.The visual acuity had improved from light perception preoperatively to 20/50 at the latest follow-up.No sight-threatening postoperative complications were noted.Conclusion:It is safe and effective to peel off the keratolenticular adhesion in patients of type 2 Peters anomaly presented with distinctly demarcated corneal opacity.展开更多
Background:Type 2 Peters anomaly is a rare anterior segment disorder characterized by central corneal leukoma with keratolenticular adhesion and cataract.Performing cataract surgery without corneal tissue transplantat...Background:Type 2 Peters anomaly is a rare anterior segment disorder characterized by central corneal leukoma with keratolenticular adhesion and cataract.Performing cataract surgery without corneal tissue transplantation in patients of type 2 Peters anomaly is extremely rare and challenging.We present a case of type 2 Peters anomaly treated by peeling off the adhesion without penetrating keratoplasty(PKP),in which restoration of corneal transparency is observed.Case presentation:An 11-month-old female infant of type 2 Peters anomaly presented with bilateral corneal opacity with distinct demarcation,keratolenticular adhesion and cataract,which was first noted at the age of 3 months.By peeling off the adhesion from corneal endothelium combined with lensectomy and vitrectomy,there was a gradual reduction in corneal opacity and improvement in visual acuity after surgery over a 2-year period.Her visual acuity had improved from light perception preoperatively to 20/50 at the latest follow-up.No sight-threatening postoperative complications were noted.Conclusion:It is safe and effective to peel off the keratolenticular adhesion in patients of type 2 Peters anomaly presented with distinctly demarcated corneal opacity.展开更多
基金supported by the National Natural Science Foundation of China(22138009)the Fundamental Research Funds for the Central Universities of China。
文摘The metal promoted In_(2)O_(3) catalysts for CO_(2) hydrogenation to methanol have attracted wide attention because of their high activity with high methanol selectivity.However,there was still no experimental confirmation if copper could be a good promoter for In_(2)O_(3).Herein,the Cu promoted In_(2)O_(3) catalyst was prepared using a deposition-precipitation method.Such prepared Cu/In_(2)O_(3) catalyst shows significantly higher CO_(2) conversion and space time yield(STY)of methanol,compared to the un-promoted In_(2)O_(3) catalyst.The loading of Cu facilitates the activation of both H_(2) and CO_(2) with the interface between the Cu cluster and defective In_(2)O_(3) as the active site.The Cu/In_(2)O_(3) catalyst takes the CO hydrogenation pathway for methanol synthesis from CO_(2) hydrogenation.It exhibits a unique size effect on the CO adsorption.At temperatures below 250℃,CO adsorption on Cu/In_(2)O_(3) is stronger than that on In_(2)O_(3),causing higher methanol selectivity.With increasing temperatu res,the Cu catalyst aggregates,which leads to the formation of weak CO adsorption site and causes a decrease in the methanol selectivity.Compared with other metal promoted In_(2)O_(3) catalysts,it can be concluded that the catalyst with stronger CO adsorption possesses higher methanol selectivity.
基金supported by the National Natural Science Foundation of China(82171001,82222015)Research Funding from West China School/Hospital of Stomatology Sichuan University(RCDWJS2023-1)Align Technology Specialized Scientific Research Fund(21H0922).
文摘Malocclusion,identified by the World Health Organization(WHO)as one of three major oral diseases,profoundly impacts the dental-maxillofacial functions,facial esthetics,and long-term development of~260 million children in China.Beyond its physical manifestations,malocclusion also significantly influences the psycho-social well-being of these children.Timely intervention in malocclusion can foster an environment conducive to dental-maxillofacial development and substantially decrease the incidence of malocclusion or reduce the severity and complexity of malocclusion in the permanent dentition,by mitigating the negative impact of abnormal environmental influences on the growth.Early orthodontic treatment encompasses accurate identification and treatment of dental and maxillofacial morphological and functional abnormalities during various stages of dental-maxillofacial development,ranging from fetal stages to the early permanent dentition phase.From an economic and societal standpoint,the urgency for effective early orthodontic treatments for malocclusions in childhood cannot be overstated,underlining its profound practical and social importance.This consensus paper discusses the characteristics and the detrimental effects of malocclusion in children,emphasizing critical need for early treatment.It elaborates on corresponding core principles and fundamental approaches in early orthodontics,proposing comprehensive guidance for preventive and interceptive orthodontic treatment,serving as a reference for clinicians engaged in early orthodontic treatment.
基金the financial supports from the National Natural Science Foundation of China (No. 11975082)。
文摘For the recycling of Pd and Ag from high-level liquid waste(HLLW), the electrochemical behaviors of Pd and Ag in the simulated HNO_(3) solutions were investigated by cyclic voltammetry and potentiostatic deposition.Scanning electron microscopy(SEM) and X-ray diffraction(XRD) were used to-observe the deposits morphology and to evaluate their composition. The results indicate that the formation of NO_(2)^(-)electrodeposited. When Pd and Ag are electrodeposited together, more metals are gained in the same time, and the deposited Ag does not dissolve in this situation. The metals are electrodeposited completely at the potentials from -0.4 to -0.6 V(vs MSE) and the deposits contai-n Ag and PdHx. The electrodeposition of Pd can boost h-ydrogen evolution,and then the reaction between H;and NO_(2)^(-)is sped up, thereby lowering the concentration of NO_(2)^(-)and inhibiting the dissolution of Ag.
基金Supported by Natural Science Foundation of Zhejiang Province (No.LQ19H120001)。
文摘·AIM:To evaluate optic nerve head(ONH)vessel density(VD)changes after cataract surgery using optical coherence tomography angiography(OCTA).·METHODS:This was a prospective observational study.Thirty-four eyes with mild/moderate cataracts were included.ONH scans were obtained before and 3mo after cataract surgery using OCTA.Radial peripapillary capillary(RPC)density,all VD,large VD and retinal nerve fiber layer thickness(RNFLT)in total disc,inside disc,and different peripapillary sectors were assessed and analyzed.Image quality score(QS),fundus photography grading and bestcorrected visual acuity(BCVA)were also collected,and correlation analyses were performed between VD change and these parameters.·RESULTS:Compared with baseline,both RPC and all VD increased in inside disc area 3mo postoperatively(from 47.5%±5.3%to 50.2%±3.7%,and from 57.87%±4.30%to 60.47%±3.10%,all P<0.001),but no differences were observed in peripapillary area.However,large VD increased from 5.63%±0.77%to 6.47%±0.72%in peripapillary ONH region(P<0.001).RPC decreased in inferior and superior peripapillary ONH parts(P=0.019,<0.001 respectively).There were obvious negative correlations between RPC change and large VD change in inside disc,superior-hemi,and inferior-hemi(r=-0.419,-0.370,and-0.439,P=0.017,0.044,and 0.015,respectively).No correlations were found between VD change and other parameters including QS change,fundus photography grading,postoperative BCVA,and postoperative peripapillary RNFLT.·CONCLUSION:RPC density and all VD in the inside disc ONH region increase 3mo after surgery in patients with mild to moderate cataract.No obvious VD changes are found in peripapillary area postoperatively.
基金funded by the National Natural Science Foundation of China (11902056, 11632004, 11902053, and U1864208)the National Key Research and Development Program of China (2018YFC1105800)+7 种基金the National Science and Technology Major Project (2017-VII-0011-0106)the Key Program for International Science and Technology Cooperation Projects of the Ministry of Science and Technology of China (2016YFE0125900)the Key Project of Natural Science Foundation of CQ CSTC (cstc2017jcyj BX0063)Science and Technology Planning Project of Tianjin (20ZYJDJC00030)Key Program of Research and Development of Hebei Province (202030507040009)the Fund for Innovative Research Groups of Natural Science Foundation of Hebei Province (A2020202002)the Key Project of Natural Science Foundation of Tianjin (S20ZDF077)the China Postdoctoral Science Foundation funded project (2019M653334 and 2020M680842)。
文摘Previous experimental and computational results have confirmed that the thermal conductivity of a twodimensional(2D) material can be considerably affected by strain. Numerous attention has been paid to explore the relevant mechanisms. However, the strain effects on the interfacial thermal conductance(ITC) of 2D heterostructure have attracted little attention. Herein, the non-equilibrium molecular dynamics(NEMD) simulations were conducted to the graphene/hexagonal boron nitride(GR/h-BN) heterostructure to investigate the strain effects on the ITC. Three types of strains were considered, i.e., tensile strain, compressive strain, and shear strain.The results indicate that the strain can adjust the ITC for the GR/h-BN heterostructure effectively, and the strain loading direction also influences the ITC. Generally, the tensile strain reduces the ITC of the heterostructure, in addition to the BN-C system at small tensile strain;both the compressive strain and shear strain increase the ITC,especially at a small strain. For the NB-C system, it is more sensitive to the strain loading direction and the yx shear strain of 0.06 is the most effective way to strengthen the ITC. Our results also show that the out-of-plane deformation weakens the in-plane vibration of atoms, leading to a reduction of the interfacial thermal energy transport.
基金the National Key Research and Development Project(No.2018YFC1503206)the National Natural Science Foundation of China(No.41674046).
文摘In this study,Qilian Mountain active source airgun signals recorded at 79 stations were obtained after stacking waveforms from July 2015 to December 2016.Based on analysis of the amplitude variation characteristics of the airgun signals,the following conclusions were drawn:along the NW-SE fault distribution direction of the Qilian Mountain area,the decrease in amplitude of airgun signals was relatively slow in relation to the epicentral distance,while the decrease in amplitude in the direction perpendicular to the fault was relatively fast.This difference may be related to the energy loss of seismic waves reflecting and scattering by the regional faults mainly distributed along the NW-SE direction,which are caused by tectonic compression of the QinghaiTibet and Alxa blocks.
基金supported by the National Social Science Foundation of China(21AZD060),Chinathe National Natural Science Foundation of China(51721006),Chinathe High-Performance Computing Platform of Peking University,China.
文摘Water diversion is a common strategy to enhance water quality in eutrophic lakes by increasing available water resources and accelerating nutrient circulation.Its effectiveness depends on changes in the source water and lake conditions.However,the challenge of optimizing water diversion remains because it is difficult to simultaneously improve lake water quality and minimize the amount of diverted water.Here,we propose a new approach called dynamic water diversion optimization(DWDO),which combines a comprehensive water quality model with a deep reinforcement learning algorithm.We applied DWDO to a region of Lake Dianchi,the largest eutrophic freshwater lake in China and validated it.Our results demonstrate that DWDO significantly reduced total nitrogen and total phosphorus concentrations in the lake by 7%and 6%,respectively,compared to previous operations.Additionally,annual water diversion decreased by an impressive 75%.Through interpretable machine learning,we identified the impact of meteorological indicators and the water quality of both the source water and the lake on optimal water diversion.We found that a single input variable could either increase or decrease water diversion,depending on its specific value,while multiple factors collectively influenced real-time adjustment of water diversion.Moreover,using well-designed hyperparameters,DWDO proved robust under different uncertainties in model parameters.The training time of the model is theoretically shorter than traditional simulation-optimization algorithms,highlighting its potential to support more effective decisionmaking in water quality management.
基金supported by the National Natural Science Foundation of China (No. 41101180)the China National Water Pollution Control Program (No.2010ZX07102-006)
文摘Lake Fuxian is the largest deep freshwater lake in China. Although its average water quality meets Class I of the China National Water Quality Standard (CNWQS), i.e., GB3838-2002, monitoring data indicate that the water quality approaches the Class II threshold in some areas. Thus it is urgent to reduce the watershed load through the total maximum daily load (TMDL) program. A three-dimensional hydrodynamic and water quality model was developed for Lake Fuxian, simulating flow circulation and pollutant fate and transport. The model development process consists of several steps, including grid generation, initial and boundary condition configurations, and model calibration processes. The model accurately reproduced the observed water surface elevation, spatiotemporal variations in temperature, and total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) concentrations, suggesting a reasonable numerical representation of the prototype system for further TMDL analyses. The TMDL was calculated using two interpretations of the water quality standards for Class I of the CNWQS based on the maximum instantaneous surface and annual average surface water concentrations. Analysis of the first scenario indicated that the TN, TP and COD loads should be reduced by 66%, 68% and 57%, respectively. Water quality was the highest priority; however, local economic development and cost feasibility for load reduction can pose significant issues. In the second interpretation, the model results showed that, under the existing conditions, the average water quality meets the Class I standard and therefore load reduction is unnecessary. Future studies are needed to conduct risk and cost assessments for realistic decision-making.
文摘Near-infrared (NIR) persistent-luminescence nanoparticles have emerged as a new class of background-free contrast agents that are promising for in vivo imaging. The next key roadblock is to establish a robust and controllable method for synthesizing monodisperse nanoparticles with high luminescence brightness and long persistent duration. Herein, we report a synthesis strategy involving the coating/etching of the SiO2 shell to obtain a new class of small NIR highly persistent luminescent ZnGa2O4:Cr^3+,Sn^4+(ZGOCS) nanoparticles. The optimized ZGOCS nanoparticles have an excellent size distribution of -15 nm without any agglomeration and an NIR persistent luminescence that is enhanced by a factor of 13.5, owing to the key role of the SiO2 shell in preventing nanoparticle agglomeration after annealing. The ZGOCS nanoparticles have a signal-to-noise ratio -3 times higher than that of previously reported ZnGa204:Cr^3+ (ZGC-1) nanoparticles as an NIR persistent-luminescence probe for in vivo bioimaging. Moreover, the persistent-luminescence signal from the ZGOCS nanoparticles can be repeatedly re-charged in situ with external excitation by a white light- emitting diode; thus, the nanopartides are suitable for long-term in vivo imaging applications. Our study suggests an improved strategy for fabricating novel high-performance optical nanoparticles with good biocompatibility.
基金This work is financially supported by the National Natural Science Founda-tion of China(No.52003171)Fundamental Research Funds for the Central Universities,China(No.YJ201823+2 种基金YJ201959)Sichuan Province Science and Technology Support Program,China(No.2020YJ0316,2021YJ0290)the Science and Technology Cooperation Project between Sichuan University and Zigong City(No:2019CDZG-23).
文摘Recently,metal–organic frameworks(MOFs)have received considerable attention as highly efficient adsorbents for dye wastewater remediation.However,the immobilization of MOFs on the substrate surfaces to fabricate easy recy-clable adsorbents via a facile route is still a challenge.In this work,ZIF-67/cotton fibers as adsorbents for dye removal were prepared in a large-scale using a simple coordination replication method.The successful fabrication of the ZIF-67/cotton fibers was confirmed by FTIR,XRD,XPS,SEM and BET analysis,respectively.As expected,the as-prepared ZIF-67/cotton fibers exhibited high adsorption capacity of 3787 mg/g towards malachite green(MG).Meanwhile,the adsorption kinetics and isotherm obeyed the pseudo-second-order kinetics and Langmuir model,respectively.Moreover,its removal efficiency towards MG was not significantly influenced by the pH and ionic strength of aque-ous solution.Most importantly,the ZIF-67/cotton fibers can remove MG from synthetic effluents,and it can be easily regenerated without filtration or centrifugation processes,with the regeneration efficiency remaining over 90%even after 10 cycles.Additionally,the ZIF-67/cotton fibers presented excellent antimicrobial performance against E.coli and S.aureus.Hence,the distinctive features of the as-prepared ZIF-67/cotton fibers make it promisingly applicable for the colored wastewater treatment.
基金This paper was supported by the National Natural Science Foundation of China (Grant No. 41222002), Research Fund for the Doctoral Program of Higher Education of China (20100001120020) and "China National Water Pollution Control Program" (2013ZX07102-006). Special thanks to Dr. Daniel Obenour in University of Michigan.
文摘To enhance the effectiveness of watershed load reduction decision making, the Risk Explicit Interval Linear Programming (REILP) approach was developed in previous studies to address decision risks and system returns. However, REILP lacks the capability to analyze the tradeoff between risks in the objective function and constraints. Therefore, a refined REILP model is proposed in this study to further enhance the decision support capability of the REILP approach for optimal watershed load reduction. By introducing a tradeofffactor (α) into the total risk function, the refined REILP can lead to different compromises between risks associated with the objective functions and the constraints. The proposed model was illustrated using a case study that deals with uncertainty- based optimal load reduction decision making for Lake Qionghai Watershed, China. A risk tradeoff curve with different values of a was presented to decision makers as a more flexible platform to support decision formulation. The results of the standard and refined REILP model were compared under 11 aspiration levels. The results demon- strate that, by applying the refined REILP, it is possible to obtain solutions that preserve the same constraint risk as that in the standard REILP but with lower objective risk, which can provide more effective guidance for decision makers.
文摘Background:Type 2 Peters ano maly is a rare anted or segment disorder characterized by central corneal leukoma with keratolenticular adhesion and cataract.Performing cataract surgery without corneal tissue transplantation in patients of type 2 Peters anomaly is extremely rare and challenging.We present a case of type 2 Peters anomaly treated by peeling off the adhesion without penetrating keratoplasty(PKP),in which restoration of corneal transparency is observed.Case presentation:An 11-month-old female infant of type 2 Peters anomaly presented with bilateral corneal opacity with distinct demarcation,keratolenticular adhesion and cataract,which was first noted at the age of 3 months.By peeling off the adhesion from comeal endothelium combined with lensectomy and vitrectomy,there was a gradual reduction in corneal opacity and improvement in visual acuity after surgery over a 2-year period.The visual acuity had improved from light perception preoperatively to 20/50 at the latest follow-up.No sight-threatening postoperative complications were noted.Conclusion:It is safe and effective to peel off the keratolenticular adhesion in patients of type 2 Peters anomaly presented with distinctly demarcated corneal opacity.
文摘Background:Type 2 Peters anomaly is a rare anterior segment disorder characterized by central corneal leukoma with keratolenticular adhesion and cataract.Performing cataract surgery without corneal tissue transplantation in patients of type 2 Peters anomaly is extremely rare and challenging.We present a case of type 2 Peters anomaly treated by peeling off the adhesion without penetrating keratoplasty(PKP),in which restoration of corneal transparency is observed.Case presentation:An 11-month-old female infant of type 2 Peters anomaly presented with bilateral corneal opacity with distinct demarcation,keratolenticular adhesion and cataract,which was first noted at the age of 3 months.By peeling off the adhesion from corneal endothelium combined with lensectomy and vitrectomy,there was a gradual reduction in corneal opacity and improvement in visual acuity after surgery over a 2-year period.Her visual acuity had improved from light perception preoperatively to 20/50 at the latest follow-up.No sight-threatening postoperative complications were noted.Conclusion:It is safe and effective to peel off the keratolenticular adhesion in patients of type 2 Peters anomaly presented with distinctly demarcated corneal opacity.