A low rare-earth containing ZEK100-O magnesium alloy was welded to AA1230-clad high-strength AA2024-T3 aluminum alloy via solidstate ultrasonic spot welding(USW)to evaluate the microstructure,tensile lap shear strengt...A low rare-earth containing ZEK100-O magnesium alloy was welded to AA1230-clad high-strength AA2024-T3 aluminum alloy via solidstate ultrasonic spot welding(USW)to evaluate the microstructure,tensile lap shear strength,and fatigue properties.The tensile strength increased with increasing welding energy,peaked at a welding energy of 1000 J,and then decreased due to the formation of an increasingly thick diffusion layer mainly containing Al12Mg17intermetallic compound at higher energy levels.The peak tensile lap shear strength attained at 1000 J was attributed to the optimal inter-diffusion between the magnesium alloy and softer AA1230-clad Al layer along with the presence of‘fishhook'-like mechanical interlocks at the weld interface and the formation of an indistinguishable intermetallic layer.The dissimilar joints welded at 1000 J also exhibited a longer fatigue life than other Mg-Al dissimilar joints,suggesting the beneficial role of the softer clad layer with a better intermingling capacity during USW.While the transverse-through-thickness(TTT)failure mode prevailed at lower cyclic loading levels,interfacial failure was the predominant mode of fatigue failure at higher cyclic loads,where distinctive fatigue striations were also observed on the fracture surface of the softer clad Al layer.This was associated with the presence of opening stress and bending moment near the nugget edge despite the tension-tension lap shear cyclic loading applied.展开更多
Background:Congenital heart disease(CHD)results from abnormal heart development during fetal development,leading to life-threatening complications.This study aimed to evaluate the feasibility of applying myocardial pa...Background:Congenital heart disease(CHD)results from abnormal heart development during fetal development,leading to life-threatening complications.This study aimed to evaluate the feasibility of applying myocardial parametric mapping in post-mortem magnetic resonance imaging and to examine differences in the left ventricular myocardium between fetuses with CHD and controls.Methods:This prospective case–control study was conducted on 14 deceased fetuses with CHD(CHD group)and 24 fetuses without CHD(control group).Fetuses with CHD were further stratified into the cyanotic(n=9)and non-cyanotic(n=5)CHD groups.T1,T2,and proton density relaxation times of the left ventricular myocardium were calculated and compared using multiple-dynamic multiple-echo post-mortem magnetic resonance imaging technology.Results:The myocardial T2 relaxation time was significantly different between the groups(p=0.033),with no difference in T1 or proton density relaxation times between the groups.A one-way analysis of variance with Tukey's test showed that the mean cyanotic CHD group showed a longer myocardial T2 relaxation time than the control group(98.00013.143 vs.83.5429.491 ms,p=0.003).Additionally,the correlation coefficient in the CHD group was significantly different between the myocardial T2 relaxation time and peak systolic velocity of pulmonary artery on a fetal echocardiogram(r2=0.681,p=0.010).Conclusions:These results suggest that using myocardial alterations in the T2 relaxation time may provide a accurate early warning for myocardial injury and enable noninvasive recognition of cardiac involvement in fetuses with CHD.展开更多
A 28-year-old pregnant woman with no prior obstetric complications had a normal prenatal workup before 24 weeks'gestation.At 24 weeks,ultrasound revealed gastrointestinal malformations,a persistent left superior v...A 28-year-old pregnant woman with no prior obstetric complications had a normal prenatal workup before 24 weeks'gestation.At 24 weeks,ultrasound revealed gastrointestinal malformations,a persistent left superior vena cava,and polyhydramnios.展开更多
Active tectonic movements and geological disasters frequently occur in the upper reaches of the Jinsha River,increasing the likelihood of landslides obstructing the river.Taking the ancient Rongcharong landslide dam f...Active tectonic movements and geological disasters frequently occur in the upper reaches of the Jinsha River,increasing the likelihood of landslides obstructing the river.Taking the ancient Rongcharong landslide dam failure events in the Suwalong reach as an example,this paper first analyzes the accuracy and applicability of the commonly used methods in calculating the peak flow of the dam failure,such as the empirical formula,the numerical method based on the physical mechanism,and the computational fluid dynamics(CFD)method.Then,the peak flood flow of the Rongcharong-dammed lake when it overflows the dam is determined to be 28393-64272 m~3/s.At the same time,the failure process of landslide dam due to flood erosion was elucidated using the CFD method,which can be divided into three stages:gradual erosion in the initial stage,rapid development in the middle stage,and gradual expansion in the final stage.Finally,the factors that affect the peak flow of floods are analyzed,and suggestions for emergency treatment of landslide dams are put forward.The findings of this research can serve as a valuable reference for disaster prevention and mitigation strategies to adapt to the increasing frequency of landslide-induced river blockages.展开更多
The selection of twin variants plays a critical role in shaping the deformation texture and mechanical properties of magnesium alloys that are limited by slip systems and diverse twinning modes.In this study,we invest...The selection of twin variants plays a critical role in shaping the deformation texture and mechanical properties of magnesium alloys that are limited by slip systems and diverse twinning modes.In this study,we investigated the twin variant selection and the effect of twinning activity on the strain hardening of a hot-rolled AZ31 magnesium alloy by quasi-in-situ EBSD.Moreover,the Schmid factors and the displacement gradient tensors were computed to evaluate the activation of twin variants.The results reveal that the yield strength increased progressively after each deformation step,driven by grain subdivision and texture hardening induced by extension{1012}twinning and the Basinski effect at large strains.The nucleation and growth of the{1012}twins occurred either sequentially or simultaneously during the plastic deformation.At low plastic strains,the activation of most twin variants followed the high Schmid factor criterion while the other twin variants with lower Schmid factors were activated due to the interactions with preexisting twins characterized by high misorientation angles(around 60°).Additionally,this non-Schmid factor scenario was also attributed to low coordinated strain requirements from neighboring grains,showing the critical role of local deformation accommodation in the twinning process.These findings advance the fundamental understanding of the twin variant selection and its implications for the microstructure-property relationship in magnesium alloys for structural applications.展开更多
Although graphite(G)materials dominate the commercial lithium-ion battery(LIBs)anode market due to their excellent overall performance,their limited rate performance and cycle life hinder applications in highperforman...Although graphite(G)materials dominate the commercial lithium-ion battery(LIBs)anode market due to their excellent overall performance,their limited rate performance and cycle life hinder applications in highperformance fields.To improve the cycling and rate performance of graphite anodes,this study first employed economical and eco-friendly tannic acid(TA)as a carbon coating precursor to coat graphite surfaces viaπ-πstacking interactions.In an oxygen-rich alkaline environment,tannic acid undergoes oxidation polymerization and crosslinks with formaldehyde to form a polymer matrix that coats the graphite surface.After subsequent carbonization,carbon-coated graphite material(G@C)was successfully synthesized.Carbon coatings on graphite effectively lower LIB resistance,enhance lithium-ion diffusion,and prevent exfoliation during cycling,thereby significantly boosting rate performance and prolonging the cycle life of graphite.After 500 cycles at 2C,the specific capacity of G@C was 103.7 mAh g^(-1),with a retention of 89%.However,G exhibited only 68.7 mAh g^(-1) and 85%retention under identical conditions.This carbon-coated graphite modification strategy offers a novel,green,and economical approach for designing and tailoring graphite anode materials for lithium-ion batteries with long cycle life and high rate.展开更多
The hole transport layer(HTL)-free carbon-based perovskite solar cells(C-PSCs)are promising for commercialization owing to their excellent operational stability and simple fabrication process.However,the power convers...The hole transport layer(HTL)-free carbon-based perovskite solar cells(C-PSCs)are promising for commercialization owing to their excellent operational stability and simple fabrication process.However,the power conversion efficiencies(PCE)of C-PSCs are inferior to the metal electrode-based devices due to their open-circuit voltage(V_(oc))loss.Herein,time-resolved confocal photoluminescence microscopy reveals that grain boundary defects at the perovskite/carbon interface are very likely to function as nonradiative recombination centers in HTL-free C-PSCs.A versatile additive Li_(2)CO_(3)is used to modify the conformal tin oxide electron transport layer for HTL-free C-PSCs.Li_(2)CO_(3)modification can result in enhanced charge extraction and optimized energy alignment at electron transport layer/perovskite interface,as well as suppressed defects at perovskite top surface due to Li_(2)CO_(3)-induced formation of PbI_(2)crystallites.Such dual interfacial passivation ultimately leads to significantly improved Voc up to 1.142 V,which is comparable to the metal electrode-based devices with HTL.Moreover,a record-high PCE of 33.2%is achieved for Li_(2)CO_(3)-modified C-PSCs under weak light illumination conditions,demonstrating excellent indoor photovoltaic performance.This work provides a practical approach to fabricate low-cost,highly efficient carbon-based perovskite solar cells.展开更多
When a pump laser beam strikes the surface of a nonlinear crystal with modulated second-order nonlinearity,various nonlinear diffraction phenomena occur,with nonlinear Raman–Nath diffraction(NRND)being a prominent ex...When a pump laser beam strikes the surface of a nonlinear crystal with modulated second-order nonlinearity,various nonlinear diffraction phenomena occur,with nonlinear Raman–Nath diffraction(NRND)being a prominent example.In this study,we use an 800-nm Ti:sapphire femtosecond laser beam to pump the surface of a periodically poled lithium niobate(PPLN)crystal thin-plate nonlinear grating.By rotating the crystal,we change the incidence angle and observe and measure the exit angle,polarization,and power of NRND spots on the other side of the crystal.The experiment shows that NRND characteristics are highly sensitive to the incidence angle of the pump laser beam,which are consistent with the theoretical prediction.We expect that this research will advance the understanding of nonlinear diffraction and provide valuable insights for nonlinear optical interaction in complicated geometric and physical configurations.展开更多
When a laser beam is incident on a nonlinear grating with a laterally modulated second-order nonlinear coefficient,nonlinear diffraction of the noncollinear second-harmonic generation(SHG)signal occurs,with Raman–Nat...When a laser beam is incident on a nonlinear grating with a laterally modulated second-order nonlinear coefficient,nonlinear diffraction of the noncollinear second-harmonic generation(SHG)signal occurs,with Raman–Nath nonlinear diffraction(NRND)being a prominent example.As these SHG NRND processes involve coupling between the fundamental-wave pump laser vectorial field and the SHG laser vectorial field through the second-order nonlinearity secondrank tensor of the nonlinear crystal,the nonlinear interaction between light and the nonlinear grating can be manipulated by adjusting the polarization state of the pump laser.In this paper,we derive the relationship between the polarization state of the incident light and the generated nonlinear diffraction signal based on the nonlinear coupled wave equation and experimentally validate the predicted diffraction characteristics.The results show that the optical properties of each order of NRND are highly sensitive to the polarization angle of the incident pump laser beam.展开更多
The electropulsing process can be used to tailor the microstructure and deformability of metallic glasses(MGs).Here,we report the microstructural origin of enhanced electroplasticity of monatomic Ta MG nanowires.Under...The electropulsing process can be used to tailor the microstructure and deformability of metallic glasses(MGs).Here,we report the microstructural origin of enhanced electroplasticity of monatomic Ta MG nanowires.Under electromechanical loading,the Ta MG nanowire exhibits improved ductility and ob-vious necking behavior.By evaluating the dynamic structural evolution via in situ diffraction,it is found that the atomic mobility in flow units of Ta MG can be improved significantly under the stimulation of pulse current,mainly through the athermal electron-atom interaction,which results in the fast annihila-tion of flow units and,thereby,fast structural relaxation.These structural evolution processes can help to eliminate the formation of the obvious shear band.These findings provide insight into the origin of elec-troplasticity in amorphous materials,which is of scientific and technological significance for the design and processing of a variety of MGs.展开更多
The active components,targets,and pathways of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis and the mechanism of action were explored by means of network pharmacology.Firstly,the active comp...The active components,targets,and pathways of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis and the mechanism of action were explored by means of network pharmacology.Firstly,the active components and related targets of Jujubae Fructus were screened by TCMSP database and standardized by Uniprot database.The compounds of Euphorbia fischeriana Steud.were obtained by searching the literature and finally screened by PubChem database,Swiss ADME,and SwissTargetPrediction.Hepatocirrhosis targets were obtained through Genecards database,PPI network analysis was conducted on common targets of Euphorbia fischeriana Steud.-Jujubae Fructus and hepatocirrhosis by using String database,GO enrichment analysis and KEGG pathway enrichment analysis was conducted through Metascape database by using intersection targets of Euphorbia fischeriana Steud.-Jujubae Fructus and hepatocirrhosis,and the results were drawn by using Weishengxin online drawing platform.Then,the network of drug-compound-target-pathway was constructed by the software of Cytoscape3.8.0.Finally,the above results were verified by molecular docking.47 active compounds from Euphorbia fischeriana Steud.-Jujubae Fructus were screened out,which had 38 common targets,162 intersection targets,and 340 signal pathways with hepatocirrhosis,mainly involving hepatitis C,JAK-STAT signal pathway and AGE-RAGE signal pathway.Targets,such as MAPK1,AKT1,TNF,JUN,IL6 and PTGS2,play important roles in the treatment.The findings suggested that the main active ingredients of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis are quercetin,scopolamine,physcion,7-deoxyrangduin,17-Hydroxyjolkinolide A,etc.Molecular docking results showed that the main active components and core targets might have a good binding capacity.This study preliminarily explored the potential mechanism of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis and provided a theoretical basis for the clinical application of Euphorbia fischeriana Steud.-Jujubae Fructus.展开更多
<div style="text-align:justify;"> Knowledge tracking model has been a research hotspot in the field of educational data mining for a long time. Knowledge tracking can automatically discover students’ ...<div style="text-align:justify;"> Knowledge tracking model has been a research hotspot in the field of educational data mining for a long time. Knowledge tracking can automatically discover students’ weak knowledge points, which helps to improve students’ self-motivation in learning and realize personalized guidance. The existing KT model has some shortcomings, such as the limitation of the calculation of knowledge growth, and the imperfect forgetting mechanism of the model. To this end, we proposed a new knowledge tracking model based on learning process (LPKT), LPKT applies the idea of Memory Augmented Neural Net-work(MANN).When we model the learning process of students, two additional important factors are considered. One is to consider the current state of knowledge of the students when updating the dynamic matrix of the neural network, and the other is to improve the forgetting mechanism of the model. In this paper we verified the effectiveness and superiority of LPKT through comparative experiments, and proved that the model can improve the effect of knowledge tracking and make the process of deep knowledge tracking easier to understand. </div>展开更多
Fish morphological phenotypes are important resources in artificial breeding,functional gene mapping,and population-based studies in aquaculture and ecology.Traditional morphological measurement of phenotypes is rathe...Fish morphological phenotypes are important resources in artificial breeding,functional gene mapping,and population-based studies in aquaculture and ecology.Traditional morphological measurement of phenotypes is rather expensive in terms of time and labor.More importantly,manual measurement is highly dependent on operational experience,which can lead to subjective phenotyping results.Here,we developed 3DPhenoFish software to extract fish morphological phenotypes from three-dimensional(3D)point cloud data.Algorithms for background elimination,coordinate normalization,image segmentation,key point recognition,and phenotype extraction were developed and integrated into an intuitive user interface.Furthermore,18 key points and traditional 2D morphological traits,along with 3D phenotypes,including area and volume,can be automatically obtained in a visualized manner.Intuitive fine-tuning of key points and customized definitions of phenotypes are also allowed in the software.Using 3DPhenoFish,we performed high-throughput phenotyping for four endemic Schizothoracinae species,including Schizopygopsis younghusbandi,Oxygymnocypris stewartii,Ptychobarbus dipogon,and Schizothorax oconnori.Results indicated that the morphological phenotypes from 3DPhenoFish exhibited high linear correlation(>0.94)with manual measurements and offered informative traits to discriminate samples of different species and even for different populations of the same species.In summary,we developed an efficient,accurate,and customizable tool,3DPhenoFish,to extract morphological phenotypes from point cloud data,which should help overcome traditional challenges in manual measurements.3DPhenoFish can be used for research on morphological phenotypes in fish,including functional gene mapping,artificial selection,and conservation studies.3DPhenoFish is an open-source software and can be downloaded for free at https://github.com/lyh24k/3DPhenoFish/tree/master.展开更多
BACKGROUND Endoscopic balloon dilatation (EBD) has become the first line of therapy for benign esophageal strictures (ESs);however,there are few publications about the predictive factors for the outcomes of this treat...BACKGROUND Endoscopic balloon dilatation (EBD) has become the first line of therapy for benign esophageal strictures (ESs);however,there are few publications about the predictive factors for the outcomes of this treatment.AIM To assess the predictive factors for the outcomes of EBD treatment for strictures after esophageal atresia (EA) repair.METHODS Children with anastomotic ES after thoracoscopic esophageal atresia repair treated by EBD from January 2012 to December 2016 were included.All procedures were performed under tracheal intubation and intravenous anesthesia using a three-grade controlled radial expansion balloon with gastroscopy.Outcomes were recorded and predictors of the outcomes were analyzed.RESULTS A total of 64 patients were included in this analysis.The rates of response,complications,and recurrence were 96.77%,8.06%,and 2.33%,respectively.The number of dilatation sessions and complications were significantly higher in patients with a smaller stricture diameter (P=0.013 and 0.023,respectively) and with more than one stricture (P=0.014 and 0.004,respectively).The length of the stricture was significantly associated with complications of EBD (P=0.001).A longer interval between surgery and the first dilatation was related to more sessions and a poorer response (P=0.017 and 0.024,respectively).CONCLUSION The diameter,length,and number of strictures are the most important predictive factors for the clinical outcomes of endoscopic balloon dilatation in pediatric ES.The interval between surgery and the first EBD is another factor affectingresponse and the number of sessions of dilatation.展开更多
The tectonic evolution of the southwestern Yangtze Block during the Early Neoproterozoic period is still controversial because of the limited quantities of 1000–860 Ma magmatic rocks.In this study,our new LA-ICP-MS z...The tectonic evolution of the southwestern Yangtze Block during the Early Neoproterozoic period is still controversial because of the limited quantities of 1000–860 Ma magmatic rocks.In this study,our new LA-ICP-MS zircon U-Pb dating results demonstrate that the Yanbian granodiorites in the southwest Yangtze Block were emplaced at 894.6±7.4 Ma,representing the product of an 894 Ma magmatism.The Yanbian granodiorites are metaluminous to weak peraluminous with A/CNK values of 0.8–1.1,resembling Itype granitoids.They are characterized by right-inclined REE patterns with moderate to insignificant negative Eu anomalies(δEu=0.6–0.9).Their primitive mantle-normalized trace element patterns are characterized by depletion of Nb,Ta and Ti and weakly enrichment of Th.Considering the positive whole-rockεNd(t)(+5.8 to+6.8),we propose that these granodiorites originated from the partial melting of juvenile mafic lower crust.The Yanbian I-type granitoids have low Y and Nb contents similar to volcanic arc igneous rocks in the Y-Nb plot for tectonic discrimination.In conclusion,Early Neoproterozoic Yanbian granodiorites have generated in a compression setting in an active continental margin.Together with previous studies from the southwestern Yangtze Block,we suggest that the 894 Ma subduction-related Yanbian granodiorites represent the early stage of subduction at the southwestern margin of the Yangtze Block.展开更多
Evolution of precipitate and precipitate/matrix interface in artificially aged Al-Zn-Mg-Cu(-Ag)alloys has been systematically studied.In the early stage of ageing,Ag,as a fast diffuser,can promote the formation of sol...Evolution of precipitate and precipitate/matrix interface in artificially aged Al-Zn-Mg-Cu(-Ag)alloys has been systematically studied.In the early stage of ageing,Ag,as a fast diffuser,can promote the formation of solute pairs and small clusters.Solute clusters are further demonstrated to be able to act as precursors forη’precipitates by in-situ STEM heating.With prolonged ageing time,the precipitate/matrix interface evolves from the Zn-dominated interface between early-stageη’and Al matrix to the Zn and Mg co-segregatedη’/Al andη_(2)/Al interfaces.Theη’/Al interfacial layers are shown to precede the formation ofη’,while theη_(2)/Al interfaces are found to be closely related to the thickening process ofη_(2)and the involved particular atomic movements are specified.Experimental observations and DFT calculations re-veal that forη’andη_(2),Ag can dissolve into the precipitate as well as locate at the precipitate/matrix interface without showing preference.For Cu,its dissolution in the precipitate and segregation on the interface mainly occur forη_(2)rather thanη’.The incorporation of Ag and Cu does not change the defined precipitate structure.展开更多
Persistent uplift means the Qinghai-Tibet Plateau(QTP)is an ideal natural laboratory to investigate genome evolution and adaptation within highland environments.However,how paleogeographic and paleoclimatic events inf...Persistent uplift means the Qinghai-Tibet Plateau(QTP)is an ideal natural laboratory to investigate genome evolution and adaptation within highland environments.However,how paleogeographic and paleoclimatic events influence the genome and population of endemic fish species remains unclear.Glyptosternon maculatum is an ancient endemic fish found on the QTP and the only critically endangered species in the Sisoridae family.Here,we found that major transposons in the G.maculatum genome showed episodic bursts,consistent with contemporaneous geological and climatic events during the QTP formation.Notably,histone genes showed significant expansion in the G.maculatum genome,which may be mediated by long interspersed nuclear elements(LINE)repetitive element duplications.Population analysis showed that ancestral G.maculatum populations experienced two significant depressions 2.6 million years ago(Mya)and 10000 years ago,exhibiting excellent synchronization with Quaternary glaciation and the Younger Dryas,respectively.Thus,we propose that paleogeography and paleoclimate were dominating driving forces for population dynamics in endemic fish on the QTP.Tectonic movements and temperature fluctuation likely destroyed the habitat and disrupted the drainage connectivity among populations.These factors may have caused severe bottlenecks and limited migration among ancestral G.maculatum populations,resulting in the low genetic diversity and endangered status of the species today.展开更多
基金the National Natural Science Foundation of China(Grant No.51971183)supported by OU(Osaka University,Japan)program for multilateral international collaboration research in joining and welding。
文摘A low rare-earth containing ZEK100-O magnesium alloy was welded to AA1230-clad high-strength AA2024-T3 aluminum alloy via solidstate ultrasonic spot welding(USW)to evaluate the microstructure,tensile lap shear strength,and fatigue properties.The tensile strength increased with increasing welding energy,peaked at a welding energy of 1000 J,and then decreased due to the formation of an increasingly thick diffusion layer mainly containing Al12Mg17intermetallic compound at higher energy levels.The peak tensile lap shear strength attained at 1000 J was attributed to the optimal inter-diffusion between the magnesium alloy and softer AA1230-clad Al layer along with the presence of‘fishhook'-like mechanical interlocks at the weld interface and the formation of an indistinguishable intermetallic layer.The dissimilar joints welded at 1000 J also exhibited a longer fatigue life than other Mg-Al dissimilar joints,suggesting the beneficial role of the softer clad layer with a better intermingling capacity during USW.While the transverse-through-thickness(TTT)failure mode prevailed at lower cyclic loading levels,interfacial failure was the predominant mode of fatigue failure at higher cyclic loads,where distinctive fatigue striations were also observed on the fracture surface of the softer clad Al layer.This was associated with the presence of opening stress and bending moment near the nugget edge despite the tension-tension lap shear cyclic loading applied.
基金supported by Zhejiang Provincial Natural Science Foundation of China(Grant/Award number:ZCLTGY24H0401)Education Department of Zhejiang Province(Grant/Award number:Y202352970).
文摘Background:Congenital heart disease(CHD)results from abnormal heart development during fetal development,leading to life-threatening complications.This study aimed to evaluate the feasibility of applying myocardial parametric mapping in post-mortem magnetic resonance imaging and to examine differences in the left ventricular myocardium between fetuses with CHD and controls.Methods:This prospective case–control study was conducted on 14 deceased fetuses with CHD(CHD group)and 24 fetuses without CHD(control group).Fetuses with CHD were further stratified into the cyanotic(n=9)and non-cyanotic(n=5)CHD groups.T1,T2,and proton density relaxation times of the left ventricular myocardium were calculated and compared using multiple-dynamic multiple-echo post-mortem magnetic resonance imaging technology.Results:The myocardial T2 relaxation time was significantly different between the groups(p=0.033),with no difference in T1 or proton density relaxation times between the groups.A one-way analysis of variance with Tukey's test showed that the mean cyanotic CHD group showed a longer myocardial T2 relaxation time than the control group(98.00013.143 vs.83.5429.491 ms,p=0.003).Additionally,the correlation coefficient in the CHD group was significantly different between the myocardial T2 relaxation time and peak systolic velocity of pulmonary artery on a fetal echocardiogram(r2=0.681,p=0.010).Conclusions:These results suggest that using myocardial alterations in the T2 relaxation time may provide a accurate early warning for myocardial injury and enable noninvasive recognition of cardiac involvement in fetuses with CHD.
基金supported by the Natural Science Foundation of Zhejiang Province(Grant number:LGF22H040003).
文摘A 28-year-old pregnant woman with no prior obstetric complications had a normal prenatal workup before 24 weeks'gestation.At 24 weeks,ultrasound revealed gastrointestinal malformations,a persistent left superior vena cava,and polyhydramnios.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0904)the National Natural Science Foundation of China(No.42307247)。
文摘Active tectonic movements and geological disasters frequently occur in the upper reaches of the Jinsha River,increasing the likelihood of landslides obstructing the river.Taking the ancient Rongcharong landslide dam failure events in the Suwalong reach as an example,this paper first analyzes the accuracy and applicability of the commonly used methods in calculating the peak flow of the dam failure,such as the empirical formula,the numerical method based on the physical mechanism,and the computational fluid dynamics(CFD)method.Then,the peak flood flow of the Rongcharong-dammed lake when it overflows the dam is determined to be 28393-64272 m~3/s.At the same time,the failure process of landslide dam due to flood erosion was elucidated using the CFD method,which can be divided into three stages:gradual erosion in the initial stage,rapid development in the middle stage,and gradual expansion in the final stage.Finally,the factors that affect the peak flow of floods are analyzed,and suggestions for emergency treatment of landslide dams are put forward.The findings of this research can serve as a valuable reference for disaster prevention and mitigation strategies to adapt to the increasing frequency of landslide-induced river blockages.
文摘The selection of twin variants plays a critical role in shaping the deformation texture and mechanical properties of magnesium alloys that are limited by slip systems and diverse twinning modes.In this study,we investigated the twin variant selection and the effect of twinning activity on the strain hardening of a hot-rolled AZ31 magnesium alloy by quasi-in-situ EBSD.Moreover,the Schmid factors and the displacement gradient tensors were computed to evaluate the activation of twin variants.The results reveal that the yield strength increased progressively after each deformation step,driven by grain subdivision and texture hardening induced by extension{1012}twinning and the Basinski effect at large strains.The nucleation and growth of the{1012}twins occurred either sequentially or simultaneously during the plastic deformation.At low plastic strains,the activation of most twin variants followed the high Schmid factor criterion while the other twin variants with lower Schmid factors were activated due to the interactions with preexisting twins characterized by high misorientation angles(around 60°).Additionally,this non-Schmid factor scenario was also attributed to low coordinated strain requirements from neighboring grains,showing the critical role of local deformation accommodation in the twinning process.These findings advance the fundamental understanding of the twin variant selection and its implications for the microstructure-property relationship in magnesium alloys for structural applications.
基金supported by the Science and Technology Projects of the State Grid Corporation of China(5500-202323102A-1-1-ZN).
文摘Although graphite(G)materials dominate the commercial lithium-ion battery(LIBs)anode market due to their excellent overall performance,their limited rate performance and cycle life hinder applications in highperformance fields.To improve the cycling and rate performance of graphite anodes,this study first employed economical and eco-friendly tannic acid(TA)as a carbon coating precursor to coat graphite surfaces viaπ-πstacking interactions.In an oxygen-rich alkaline environment,tannic acid undergoes oxidation polymerization and crosslinks with formaldehyde to form a polymer matrix that coats the graphite surface.After subsequent carbonization,carbon-coated graphite material(G@C)was successfully synthesized.Carbon coatings on graphite effectively lower LIB resistance,enhance lithium-ion diffusion,and prevent exfoliation during cycling,thereby significantly boosting rate performance and prolonging the cycle life of graphite.After 500 cycles at 2C,the specific capacity of G@C was 103.7 mAh g^(-1),with a retention of 89%.However,G exhibited only 68.7 mAh g^(-1) and 85%retention under identical conditions.This carbon-coated graphite modification strategy offers a novel,green,and economical approach for designing and tailoring graphite anode materials for lithium-ion batteries with long cycle life and high rate.
基金supported by the National Natural Science Foundation of China(62104059,12104126,61935016,52173153)Nature Science Foundation of Hebei Province(F2021202044)the Science Research Project of Hebei Education Department(ZD2021031)。
文摘The hole transport layer(HTL)-free carbon-based perovskite solar cells(C-PSCs)are promising for commercialization owing to their excellent operational stability and simple fabrication process.However,the power conversion efficiencies(PCE)of C-PSCs are inferior to the metal electrode-based devices due to their open-circuit voltage(V_(oc))loss.Herein,time-resolved confocal photoluminescence microscopy reveals that grain boundary defects at the perovskite/carbon interface are very likely to function as nonradiative recombination centers in HTL-free C-PSCs.A versatile additive Li_(2)CO_(3)is used to modify the conformal tin oxide electron transport layer for HTL-free C-PSCs.Li_(2)CO_(3)modification can result in enhanced charge extraction and optimized energy alignment at electron transport layer/perovskite interface,as well as suppressed defects at perovskite top surface due to Li_(2)CO_(3)-induced formation of PbI_(2)crystallites.Such dual interfacial passivation ultimately leads to significantly improved Voc up to 1.142 V,which is comparable to the metal electrode-based devices with HTL.Moreover,a record-high PCE of 33.2%is achieved for Li_(2)CO_(3)-modified C-PSCs under weak light illumination conditions,demonstrating excellent indoor photovoltaic performance.This work provides a practical approach to fabricate low-cost,highly efficient carbon-based perovskite solar cells.
基金supported by the Science and Technology Project of Guangdong Province,China(Grant No.2020B010190001)the National Natural Science Foundation of China(Grant No.12434016)the National Funded Postdoctoral Researcher Program(Grant No.GZB20240785).
文摘When a pump laser beam strikes the surface of a nonlinear crystal with modulated second-order nonlinearity,various nonlinear diffraction phenomena occur,with nonlinear Raman–Nath diffraction(NRND)being a prominent example.In this study,we use an 800-nm Ti:sapphire femtosecond laser beam to pump the surface of a periodically poled lithium niobate(PPLN)crystal thin-plate nonlinear grating.By rotating the crystal,we change the incidence angle and observe and measure the exit angle,polarization,and power of NRND spots on the other side of the crystal.The experiment shows that NRND characteristics are highly sensitive to the incidence angle of the pump laser beam,which are consistent with the theoretical prediction.We expect that this research will advance the understanding of nonlinear diffraction and provide valuable insights for nonlinear optical interaction in complicated geometric and physical configurations.
基金Project supported by Science and Technology Project of Guangdong(Grant No.2020B010190001)the National Natural Science Foundation of China(Grant No.12434016)National Funded Postdoctoral Researcher Program(Grant No.GZB20240785)。
文摘When a laser beam is incident on a nonlinear grating with a laterally modulated second-order nonlinear coefficient,nonlinear diffraction of the noncollinear second-harmonic generation(SHG)signal occurs,with Raman–Nath nonlinear diffraction(NRND)being a prominent example.As these SHG NRND processes involve coupling between the fundamental-wave pump laser vectorial field and the SHG laser vectorial field through the second-order nonlinearity secondrank tensor of the nonlinear crystal,the nonlinear interaction between light and the nonlinear grating can be manipulated by adjusting the polarization state of the pump laser.In this paper,we derive the relationship between the polarization state of the incident light and the generated nonlinear diffraction signal based on the nonlinear coupled wave equation and experimentally validate the predicted diffraction characteristics.The results show that the optical properties of each order of NRND are highly sensitive to the polarization angle of the incident pump laser beam.
基金supported by the open research fund of Songshan Lake Materials Laboratory(No.2021SLABFN15)the National Natural Science Foundation of China(No.52071284)+1 种基金the Zhejiang Provincial Natural Science Foundation of China(No.LR24E010002)the Zhejiang University Global Partnership Fund.
文摘The electropulsing process can be used to tailor the microstructure and deformability of metallic glasses(MGs).Here,we report the microstructural origin of enhanced electroplasticity of monatomic Ta MG nanowires.Under electromechanical loading,the Ta MG nanowire exhibits improved ductility and ob-vious necking behavior.By evaluating the dynamic structural evolution via in situ diffraction,it is found that the atomic mobility in flow units of Ta MG can be improved significantly under the stimulation of pulse current,mainly through the athermal electron-atom interaction,which results in the fast annihila-tion of flow units and,thereby,fast structural relaxation.These structural evolution processes can help to eliminate the formation of the obvious shear band.These findings provide insight into the origin of elec-troplasticity in amorphous materials,which is of scientific and technological significance for the design and processing of a variety of MGs.
基金supported by Qiqihar Science and Technology Plan Joint Guidance Project (LSFGG-2022042).
文摘The active components,targets,and pathways of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis and the mechanism of action were explored by means of network pharmacology.Firstly,the active components and related targets of Jujubae Fructus were screened by TCMSP database and standardized by Uniprot database.The compounds of Euphorbia fischeriana Steud.were obtained by searching the literature and finally screened by PubChem database,Swiss ADME,and SwissTargetPrediction.Hepatocirrhosis targets were obtained through Genecards database,PPI network analysis was conducted on common targets of Euphorbia fischeriana Steud.-Jujubae Fructus and hepatocirrhosis by using String database,GO enrichment analysis and KEGG pathway enrichment analysis was conducted through Metascape database by using intersection targets of Euphorbia fischeriana Steud.-Jujubae Fructus and hepatocirrhosis,and the results were drawn by using Weishengxin online drawing platform.Then,the network of drug-compound-target-pathway was constructed by the software of Cytoscape3.8.0.Finally,the above results were verified by molecular docking.47 active compounds from Euphorbia fischeriana Steud.-Jujubae Fructus were screened out,which had 38 common targets,162 intersection targets,and 340 signal pathways with hepatocirrhosis,mainly involving hepatitis C,JAK-STAT signal pathway and AGE-RAGE signal pathway.Targets,such as MAPK1,AKT1,TNF,JUN,IL6 and PTGS2,play important roles in the treatment.The findings suggested that the main active ingredients of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis are quercetin,scopolamine,physcion,7-deoxyrangduin,17-Hydroxyjolkinolide A,etc.Molecular docking results showed that the main active components and core targets might have a good binding capacity.This study preliminarily explored the potential mechanism of Euphorbia fischeriana Steud.-Jujubae Fructus in treating hepatocirrhosis and provided a theoretical basis for the clinical application of Euphorbia fischeriana Steud.-Jujubae Fructus.
文摘<div style="text-align:justify;"> Knowledge tracking model has been a research hotspot in the field of educational data mining for a long time. Knowledge tracking can automatically discover students’ weak knowledge points, which helps to improve students’ self-motivation in learning and realize personalized guidance. The existing KT model has some shortcomings, such as the limitation of the calculation of knowledge growth, and the imperfect forgetting mechanism of the model. To this end, we proposed a new knowledge tracking model based on learning process (LPKT), LPKT applies the idea of Memory Augmented Neural Net-work(MANN).When we model the learning process of students, two additional important factors are considered. One is to consider the current state of knowledge of the students when updating the dynamic matrix of the neural network, and the other is to improve the forgetting mechanism of the model. In this paper we verified the effectiveness and superiority of LPKT through comparative experiments, and proved that the model can improve the effect of knowledge tracking and make the process of deep knowledge tracking easier to understand. </div>
基金supported by the National Natural Science Foundation of China(32072980)Key Research and Development Projects in Tibet(XZ202001ZY0016N,XZ201902NB02,XZNKY-2019-C-053)。
文摘Fish morphological phenotypes are important resources in artificial breeding,functional gene mapping,and population-based studies in aquaculture and ecology.Traditional morphological measurement of phenotypes is rather expensive in terms of time and labor.More importantly,manual measurement is highly dependent on operational experience,which can lead to subjective phenotyping results.Here,we developed 3DPhenoFish software to extract fish morphological phenotypes from three-dimensional(3D)point cloud data.Algorithms for background elimination,coordinate normalization,image segmentation,key point recognition,and phenotype extraction were developed and integrated into an intuitive user interface.Furthermore,18 key points and traditional 2D morphological traits,along with 3D phenotypes,including area and volume,can be automatically obtained in a visualized manner.Intuitive fine-tuning of key points and customized definitions of phenotypes are also allowed in the software.Using 3DPhenoFish,we performed high-throughput phenotyping for four endemic Schizothoracinae species,including Schizopygopsis younghusbandi,Oxygymnocypris stewartii,Ptychobarbus dipogon,and Schizothorax oconnori.Results indicated that the morphological phenotypes from 3DPhenoFish exhibited high linear correlation(>0.94)with manual measurements and offered informative traits to discriminate samples of different species and even for different populations of the same species.In summary,we developed an efficient,accurate,and customizable tool,3DPhenoFish,to extract morphological phenotypes from point cloud data,which should help overcome traditional challenges in manual measurements.3DPhenoFish can be used for research on morphological phenotypes in fish,including functional gene mapping,artificial selection,and conservation studies.3DPhenoFish is an open-source software and can be downloaded for free at https://github.com/lyh24k/3DPhenoFish/tree/master.
基金Supported by the Shenzhen Innovation and Technology Committee,No.JCYJ20180228175150018the Guangdong Medical Research Foundation(CN),No.A2018550
文摘BACKGROUND Endoscopic balloon dilatation (EBD) has become the first line of therapy for benign esophageal strictures (ESs);however,there are few publications about the predictive factors for the outcomes of this treatment.AIM To assess the predictive factors for the outcomes of EBD treatment for strictures after esophageal atresia (EA) repair.METHODS Children with anastomotic ES after thoracoscopic esophageal atresia repair treated by EBD from January 2012 to December 2016 were included.All procedures were performed under tracheal intubation and intravenous anesthesia using a three-grade controlled radial expansion balloon with gastroscopy.Outcomes were recorded and predictors of the outcomes were analyzed.RESULTS A total of 64 patients were included in this analysis.The rates of response,complications,and recurrence were 96.77%,8.06%,and 2.33%,respectively.The number of dilatation sessions and complications were significantly higher in patients with a smaller stricture diameter (P=0.013 and 0.023,respectively) and with more than one stricture (P=0.014 and 0.004,respectively).The length of the stricture was significantly associated with complications of EBD (P=0.001).A longer interval between surgery and the first dilatation was related to more sessions and a poorer response (P=0.017 and 0.024,respectively).CONCLUSION The diameter,length,and number of strictures are the most important predictive factors for the clinical outcomes of endoscopic balloon dilatation in pediatric ES.The interval between surgery and the first EBD is another factor affectingresponse and the number of sessions of dilatation.
基金the China Geological Survey(Nos.DD20190370,121201111120117)。
文摘The tectonic evolution of the southwestern Yangtze Block during the Early Neoproterozoic period is still controversial because of the limited quantities of 1000–860 Ma magmatic rocks.In this study,our new LA-ICP-MS zircon U-Pb dating results demonstrate that the Yanbian granodiorites in the southwest Yangtze Block were emplaced at 894.6±7.4 Ma,representing the product of an 894 Ma magmatism.The Yanbian granodiorites are metaluminous to weak peraluminous with A/CNK values of 0.8–1.1,resembling Itype granitoids.They are characterized by right-inclined REE patterns with moderate to insignificant negative Eu anomalies(δEu=0.6–0.9).Their primitive mantle-normalized trace element patterns are characterized by depletion of Nb,Ta and Ti and weakly enrichment of Th.Considering the positive whole-rockεNd(t)(+5.8 to+6.8),we propose that these granodiorites originated from the partial melting of juvenile mafic lower crust.The Yanbian I-type granitoids have low Y and Nb contents similar to volcanic arc igneous rocks in the Y-Nb plot for tectonic discrimination.In conclusion,Early Neoproterozoic Yanbian granodiorites have generated in a compression setting in an active continental margin.Together with previous studies from the southwestern Yangtze Block,we suggest that the 894 Ma subduction-related Yanbian granodiorites represent the early stage of subduction at the southwestern margin of the Yangtze Block.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52071284 and 51771172)the Zhejiang Provincial Natural Science Foundation of China(No.LQ22E010003).
文摘Evolution of precipitate and precipitate/matrix interface in artificially aged Al-Zn-Mg-Cu(-Ag)alloys has been systematically studied.In the early stage of ageing,Ag,as a fast diffuser,can promote the formation of solute pairs and small clusters.Solute clusters are further demonstrated to be able to act as precursors forη’precipitates by in-situ STEM heating.With prolonged ageing time,the precipitate/matrix interface evolves from the Zn-dominated interface between early-stageη’and Al matrix to the Zn and Mg co-segregatedη’/Al andη_(2)/Al interfaces.Theη’/Al interfacial layers are shown to precede the formation ofη’,while theη_(2)/Al interfaces are found to be closely related to the thickening process ofη_(2)and the involved particular atomic movements are specified.Experimental observations and DFT calculations re-veal that forη’andη_(2),Ag can dissolve into the precipitate as well as locate at the precipitate/matrix interface without showing preference.For Cu,its dissolution in the precipitate and segregation on the interface mainly occur forη_(2)rather thanη’.The incorporation of Ag and Cu does not change the defined precipitate structure.
基金supported by the Key Research and Development Projects in Tibet:Preservation of Characteristic Biological Germplasm Resources and Utilization of Gene Technology in Tibet(XZ202001ZY0016N)National Natural Science Foundation of China(32072980)Special Finance of Tibet Autonomous Region(XZNKY-2019-C-053)。
文摘Persistent uplift means the Qinghai-Tibet Plateau(QTP)is an ideal natural laboratory to investigate genome evolution and adaptation within highland environments.However,how paleogeographic and paleoclimatic events influence the genome and population of endemic fish species remains unclear.Glyptosternon maculatum is an ancient endemic fish found on the QTP and the only critically endangered species in the Sisoridae family.Here,we found that major transposons in the G.maculatum genome showed episodic bursts,consistent with contemporaneous geological and climatic events during the QTP formation.Notably,histone genes showed significant expansion in the G.maculatum genome,which may be mediated by long interspersed nuclear elements(LINE)repetitive element duplications.Population analysis showed that ancestral G.maculatum populations experienced two significant depressions 2.6 million years ago(Mya)and 10000 years ago,exhibiting excellent synchronization with Quaternary glaciation and the Younger Dryas,respectively.Thus,we propose that paleogeography and paleoclimate were dominating driving forces for population dynamics in endemic fish on the QTP.Tectonic movements and temperature fluctuation likely destroyed the habitat and disrupted the drainage connectivity among populations.These factors may have caused severe bottlenecks and limited migration among ancestral G.maculatum populations,resulting in the low genetic diversity and endangered status of the species today.
