BACKGROUND: Secondary lymphedema is one of the common complications after malignant tumor surgery. It is a chronic and complex disease. Once lymphedema occurs, there will be discomfort such as limb swelling, pain, num...BACKGROUND: Secondary lymphedema is one of the common complications after malignant tumor surgery. It is a chronic and complex disease. Once lymphedema occurs, there will be discomfort such as limb swelling, pain, numbness and tension, which will eventually lead to changes in the appearance of the affected limb and will seriously affect the quality of life and require lifelong treatment and psychosocial support. This study investigated the current situation of stigma and alexithymia in patients with lymphedema, and discussed the impact of alexithymia on stigma in patients with lymphedema. AIMS: To understand the current situation of stigma and alexithymia in patients with lymphedema, and to analyze the influence of alexithymia on stigma. METHODS: 195 patients with lymphedema in a hospital were selected by convenient sampling. General information questionnaire, Toronto Alexithymia Scale and social impact scale were used to investigate respectively, to study the general situation, stigma and alexithymia of the respondents. RESULTS: The results showed that the total score of stigma in 195 patients with lymphedema was (60.36 ± 11.08), and the total score of alexithymia was (56.53 ± 8.43). Multiple linear regression analysis showed that alexithymia and family relationship were the influencing factors of stigma in patients with lymphedema. CONCLUSIONS: The patients with lymphedema have obvious stigma, and alexithymia and family relationship are the influencing factors.展开更多
Objective: To explore the pre-treatment and efficacy analysis of comprehensive anti-inflammatory treatment for lymphedema in patients with irritating contact dermatitis. Method: Convenience sampling method was used to...Objective: To explore the pre-treatment and efficacy analysis of comprehensive anti-inflammatory treatment for lymphedema in patients with irritating contact dermatitis. Method: Convenience sampling method was used to observe the skin of 160 patients with upper limb lymphedema admitted to the lymphedema outpatient department of our hospital. They were divided into an observation group (80 cases) and a control group (80 cases), and both groups received a course of comprehensive anti-inflammatory treatment (20 treatments). The control group received routine skin care;On the basis of the control group, the observation group received pre-treatment of the affected limb skin: Laofuzi herbal ointment was applied externally to the prone areas of irritating contact dermatitis (such as the upper arm, inner forearm, and cubital fossa). Result: The incidence of irritating contact dermatitis in the observation group was significantly lower than that in the control group (P 0.05). Patients in the observation group felt significantly better in terms of comfort, skin moisture, and itching relief after being wrapped with low elasticity bandages than those in the control group (P Conclusion: Preventive treatment can effectively reduce the incidence of irritating contact dermatitis, prolong the time of stress treatment, thereby increasing efficacy and improving patient compliance.展开更多
As the channel for grain boundary diffusion(GBD)in Nd–Fe–B magnets,grain boundary(GB)phases have a very important effect on GBD.As doping elements that are commonly used to regulate the GB phases in Nd–Fe–B sinter...As the channel for grain boundary diffusion(GBD)in Nd–Fe–B magnets,grain boundary(GB)phases have a very important effect on GBD.As doping elements that are commonly used to regulate the GB phases in Nd–Fe–B sintered magnets,the influences of Ga and Zr on GBD were investigated in this work.The results show that the Zr-doped magnet has the highest coercivity increment(7.97 kOe)by GBD,which is almost twice that of the Ga-doped magnet(4.32 kOe)and the magnet without Ga and Zr(3.24 kOe).Microstructure analysis shows that ZrB_(2)formed in the Zr-doped magnet plays a key role in increasing the diffusion depth.A continuous diffusion channel in the magnet can form because of the presence of ZrB_(2).ZrB_(2)can also increase the defect concentration in GB phases,which can facilitate GBD.Although Ga can also improve the diffusion depth,its effect is not very obvious.The micromagnetic simulation based on the experimental results also proves that the distribution of Tb in the Zr-doped magnet after GBD is beneficial to coercivity.This study reveals that the doping elements Ga and Zr in Nd–Fe–B play an important role in GBD,and could provide a new perspective for researchers to improve the effects of GBD.展开更多
The relatively fragile low-temperature stability of cryogen-free superconducting magnetic resonance imaging(MRI)magnets requires the careful management of exogenous heat sources.A strongly shielded gradient magnetic f...The relatively fragile low-temperature stability of cryogen-free superconducting magnetic resonance imaging(MRI)magnets requires the careful management of exogenous heat sources.A strongly shielded gradient magnetic field is important for the optimal operation of cryogen-free MRI systems.In this study,we present an enhanced shielding method incorporating a regionalized stray field constraining strategy.By optimizing the constraint parameters,we could develop engineering-feasible gradient coil schemes without increasing system complexity but with the stray field intensity reduced by half.In real measurement in an integrated MRI system,the developed gradient assembly demonstrated good performance and supported to output images of excellent quality.Our findings suggested that the proposed method could potentially form a useful design paradigm for cryogen-free MRI magnets.展开更多
The microstructure characteristics and strengthening mechanism of Inconel738LC(IN-738LC) alloy prepared by using induction-assisted directed energy deposition(IDED) were elucidated through the investigation of samples...The microstructure characteristics and strengthening mechanism of Inconel738LC(IN-738LC) alloy prepared by using induction-assisted directed energy deposition(IDED) were elucidated through the investigation of samples subjected to IDED under 1050℃ preheating with and without hot isostatic pressing(HIP,1190℃,105 MPa,and 3 h).Results show that the as-deposited sample mainly consisted of epitaxial columnar crystals and inhomogeneously distributed γ’ phases in interdendritic and dendritic core regions.After HIP,grain morphology changed negligibly,whereas the size of the γ’ phase became increasingly even.After further heat treatment(HT,1070℃,2 h + 845℃,24 h),the γ’ phase in the as-deposited and HIPed samples presented a bimodal size distribution,whereas that in the as-deposited sample showed a size that remained uneven.The comparison of tensile properties revealed that the tensile strength and uniform elongation of the HIP + HTed sample increased by 5% and 46%,respectively,due to the synergistic deformation of bimodal γ’phases,especially large cubic γ’ phases.Finally,the relationship between phase transformations and plastic deformations in the IDEDed sample was discussed on the basis of generalized stability theory in terms of the trade-off between thermodynamics and kinetics.展开更多
Achieving composition tunability and structure editability of nanoalloys with high level strain may be an efficient strategy to remarkably boost catalytic performance toward oxygen evolution reaction(OER)in acidic wat...Achieving composition tunability and structure editability of nanoalloys with high level strain may be an efficient strategy to remarkably boost catalytic performance toward oxygen evolution reaction(OER)in acidic water oxidation.Herein,lotus root-like RuIr alloys with native micro-strain were constructed by an epitaxial growth of Ru-richened hcp-(0001)branches on Ir-richened fcc-(111)seeds using a polyol thermal synthesis strategy.The resultant Ru_(60)Ir_(40) alloy shows an OER overpotential of 197 mV at 10 mA cm^(-2) and a Tafel slope of 46.59 mV dec^(-1),showing no obvious activity decay for 80 h continuous chronopotentiometry test in 0.5 M H_(2)SO_(4).The related characterizations including X-ray absorption fine structure(XAFS)spectroscopy and density functional theory(DFT)calculations show that that the remarkably improved activity of the lotus root-like alloy can be attributed to the(0001)facet-triggered strain,which can efficiently optimize the electronic band structure of the active metal and the weakening of the chemisorption of oxygen-containing substances to boost OER electrocatalysis.Therefore,this work provides a new strategy to designing a class of advanced electrocatalysts with high strain using diverse nanostructures as building materials for carbon-free clean energy conversion systems.展开更多
Boron is an important industrial raw material often sourced from minerals containing different compounds that cocrystallize,which makes it difficult to separate the mineral phases through conventional beneficiation.Th...Boron is an important industrial raw material often sourced from minerals containing different compounds that cocrystallize,which makes it difficult to separate the mineral phases through conventional beneficiation.This study proposed a new treatment called flash reduction-melting separation(FRMS)for boron-bearing iron concentrates.In this method,the concentrates were first flash-reduced at the temperature under which the particles melt,and the slag and the reduced iron phases disengaged at the particle scale.Good reduc-tion and melting effects were achieved above 1550℃.The B_(2)O_(3) content in the separated slag was over 18wt%,and the B content in the iron was less than 0.03wt%.The proposed FRMS method was tested to investigate the effects of factors such as ore particle size and tem-perature on the reduction and melting steps with and without pre-reducing the raw concentrate.The mineral phase transformation and morphology evolution in the ore particles during FRMS were also comprehensively analyzed.展开更多
RuO_(2) has been considered a potential alternative to commercial IrO_(2) for the oxygen evolution reaction(OER)due to its superior intrinsic activity.However,its inherent structure dissolution in acidic environments ...RuO_(2) has been considered a potential alternative to commercial IrO_(2) for the oxygen evolution reaction(OER)due to its superior intrinsic activity.However,its inherent structure dissolution in acidic environments restricts its commercial applications.In this study,we report a novel Pd-doped ruthenium oxide(Pd–RuO_(2))nanosheet catalyst that exhibits improved activity and stability through a synergistic effect of Pd modulation of Ru electronic structure and the two-dimensional structure.The catalyst exhibits excellent performance,achieving an overpotential of only 204 mVat a current density of 10 mA cm^(-2).Impressively,after undergoing 8000 cycles of cyclic voltammetry testing,the overpotential merely decreased by 5 mV.The PEM electrolyzer with Pd0.08Ru0.92O_(2) as an anode catalyst survived an almost 130 h operation at 200 mA cm^(-2).To elucidate the underlying mechanisms responsible for the enhanced stability,we conducted an X-ray photoelectron spectroscopy(XPS)analysis,which reveals that the electron transfer from Pd to Ru effectively circumvents the over-oxidation of Ru,thus playing a crucial role in enhancing the catalyst's stability.Furthermore,density functional theory(DFT)calculations provide compelling evidence that the introduction of Pd into RuO_(2) effectively modulates electron correlations and facilitates the electron transfer from Pd to Ru,thereby preventing the overoxidation of Ru.Additionally,the application of the two-dimensional structure effectively inhibited the aggregation and growth of nanoparticles,further bolstering the structural integrity of the catalyst.展开更多
Crack propagation in brittle material is not only crucial for structural safety evaluation,but also has a wideranging impact on material design,damage assessment,resource extraction,and scientific research.A thorough ...Crack propagation in brittle material is not only crucial for structural safety evaluation,but also has a wideranging impact on material design,damage assessment,resource extraction,and scientific research.A thorough investigation into the behavior of crack propagation contributes to a better understanding and control of the properties of brittle materials,thereby enhancing the reliability and safety of both materials and structures.As an implicit discrete elementmethod,the Discontinuous Deformation Analysis(DDA)has gained significant attention for its developments and applications in recent years.Among these developments,the particle DDA equipped with the bonded particle model is a powerful tool for predicting the whole process of material from continuity to failure.The primary objective of this research is to develop and utilize the particle DDAtomodel and understand the complex behavior of cracks in brittle materials under both static and dynamic loadings.The particle DDA is applied to several classical crack propagation problems,including the crack branching,compact tensile test,Kalthoff impact experiment,and tensile test of a rectangular plate with a hole.The evolutions of cracks under various stress or geometrical conditions are carefully investigated.The simulated results are compared with the experiments and other numerical results.It is found that the crack propagation patterns,including crack branching and the formation of secondary cracks,can be well reproduced.The results show that the particle DDA is a qualified method for crack propagation problems,providing valuable insights into the fracture mechanism of brittle materials.展开更多
BACKGROUND Acute decompensation(AD)of cirrhosis is associated with high short-term mortality,mainly due to the development of acute-on-chronic liver failure(ACLF).Thus,there is a need for biomarkers for early and accu...BACKGROUND Acute decompensation(AD)of cirrhosis is associated with high short-term mortality,mainly due to the development of acute-on-chronic liver failure(ACLF).Thus,there is a need for biomarkers for early and accurate identification of AD patients with high risk of development of ACLF and mortality.Soluble triggering receptor expressed on myeloid cells-1(sTREM-1)is released from activated innate immune cells and correlated with various inflammatory processes.AIM To explore the prognostic value of sTREM-1 in patients with AD of cirrhosis.METHODS A multicenter prospective cohort of 442 patients with cirrhosis hospitalized for AD was divided into a study cohort(n=309)and validation cohort(n=133).Demographic and clinical data were collected,and serum sTREM-1 was measured at admission.All enrolled patients were followed-up for at least 1 year.RESULTS In patients with AD and cirrhosis,serum sTREM-1 was an independent prognosis predictor for 1-year survival and correlated with liver,coagulation,cerebral and kidney failure.A new prognostic model of AD(P-AD)incorporating sTREM-1,blood urea nitrogen(BUN),total bilirubin(TBil),international normalized ratio(INR)and hepatic encephalopathy grades was established and performed better than the model for end-stage liver disease(MELD),MELD-sodium(MELD-Na),chronic liver failure-consortium(CLIF-C)ACLF and CLIF-C AD scores.Additionally,sTREM-1 was increased in ACLF and predicted the development of ACLF during first 28-d follow-up.The ACLF risk score incorporating serum sTREM-1,BUN,INR,TBil and aspartate aminotransferase levels was established and significantly superior to MELD,MELD-Na,CLIF-C ACLF,CLIF-C AD and P-AD in predicting risk of ACLF development.CONCLUSION Serum sTREM-1 is a promising prognostic biomarker for ACLF development and mortality in patients with AD of cirrhosis.展开更多
Dielectric barrier discharge(DBD)is considered as a promising technique to produce large volume uniform plasma at atmospheric pressure,and the dielectric barrier layer between the electrodes plays a key role in the DB...Dielectric barrier discharge(DBD)is considered as a promising technique to produce large volume uniform plasma at atmospheric pressure,and the dielectric barrier layer between the electrodes plays a key role in the DBD processes and enhancing discharge uniformity.In this work,the uniformity and discharge characteristics of the nanosecond(ns)pulsed DBD with dielectric barrier layers made of alumina,quartz glass,polycarbonate(PC),and polypropylene(PP)are investigated via discharge image observation,voltage-current waveform measurement and optical emission spectral diagnosis.Through analyzing discharge image by gray value standard deviation method,the discharge uniformity is quantitatively calculated.The effects of the space electric field intensity,the electron density(Ne),and the space reactive species on the uniformity are studied with quantifying the gap voltage Ug and the discharge current Ig,analyzing the recorded optical emission spectra,and simulating the temporal distribution of Ne with a one-dimensional fluid model.It is found that as the relative permittivity of the dielectric materials increases,the space electric field intensity is enhanced,which results in a higher Ne and electron temperature(Te).Therefore,an appropriate value of space electric field intensity can promote electron avalanches,resulting in uniform and stable plasma by the merging of electron avalanches.However,an excessive value of space electric field intensity leads to the aggregation of space charges and the distortion of the space electric field,which reduce the discharge uniformity.The surface roughness and the surface charge decay are measured to explain the influences of the surface properties and the second electron emission on the discharge uniformity.The results in this work give a comprehensive understanding of the effect of the dielectric materials on the DBD uniformity,and contribute to the selection of dielectric materials for DBD reactor and the realization of atmospheric pressure uniform,stable,and reactive plasma sources.展开更多
Visual object tracking plays a crucial role in computer vision.In recent years,researchers have proposed various methods to achieve high-performance object tracking.Among these,methods based on Transformers have becom...Visual object tracking plays a crucial role in computer vision.In recent years,researchers have proposed various methods to achieve high-performance object tracking.Among these,methods based on Transformers have become a research hotspot due to their ability to globally model and contextualize information.However,current Transformer-based object tracking methods still face challenges such as low tracking accuracy and the presence of redundant feature information.In this paper,we introduce self-calibration multi-head self-attention Transformer(SMSTracker)as a solution to these challenges.It employs a hybrid tensor decomposition self-organizing multihead self-attention transformermechanism,which not only compresses and accelerates Transformer operations but also significantly reduces redundant data,thereby enhancing the accuracy and efficiency of tracking.Additionally,we introduce a self-calibration attention fusion block to resolve common issues of attention ambiguities and inconsistencies found in traditional trackingmethods,ensuring the stability and reliability of tracking performance across various scenarios.By integrating a hybrid tensor decomposition approach with a self-organizingmulti-head self-attentive transformer mechanism,SMSTracker enhances the efficiency and accuracy of the tracking process.Experimental results show that SMSTracker achieves competitive performance in visual object tracking,promising more robust and efficient tracking systems,demonstrating its potential to providemore robust and efficient tracking solutions in real-world applications.展开更多
The emergence of the internet of things has promoted wireless communication’s evolution towards multi-band and multi-area utilization.Notably,forthcoming sixth-generation(6G)communication standards,incorporating tera...The emergence of the internet of things has promoted wireless communication’s evolution towards multi-band and multi-area utilization.Notably,forthcoming sixth-generation(6G)communication standards,incorporating terahertz(THz)frequencies alongside existing gigahertz(GHz)modes,drive the need for a versatile multi-band electromagnetic wave(EMW)absorbing and shielding material.This study introduces a pivotal advance via a new strategy,called ultrafast laser-induced thermal-chemical transformation and encapsulation of nanoalloys(LITENs).Employing multivariate metal-organic frameworks,this approach tailors a porous,multifunctional graphene-encased magnetic nanoalloy(GEMN).By fine-tuning pulse laser parameters and material components,the resulting GEMN excels in low-frequency absorption and THz shielding.GEMN achieves a breakthrough of minimum reflection loss of−50.6 dB in the optimal C-band(around 4.98 GHz).Computational evidence reinforces GEMN’s efficacy in reducing radar cross sections.Additionally,GEMN demonstrates superior electromagnetic interference shielding,reaching 98.92 dB under THz band(0.1–2 THz),with the mean value result of 55.47 dB.These accomplishments underscore GEMN’s potential for 6G signal shielding.In summary,LITEN yields the remarkable EMW controlling performance,holding promise in both GHz and THz frequency domains.This contribution heralds a paradigm shift in EM absorption and shielding materials,establishing a universally applicable framework with profound implications for future pursuits.展开更多
Twisted bilayer graphene(TBG) has been extensively studied because of its novel physical properties and potential application in electronic devices.Here we report the synthesis and characterization of 300 TBG naturall...Twisted bilayer graphene(TBG) has been extensively studied because of its novel physical properties and potential application in electronic devices.Here we report the synthesis and characterization of 300 TBG naturally grown on Cu_(0.75)Ni_(0.25)(111) film and investigate the electronic structure by angle-resolved photoemission spectroscopy.Compared with other substrates,our TBG with a wafer scale is acquired with a shorter growth time.The Fermi velocity and energy gap of Dirac cones of TBG are comparable with those of a monolayer on Cu_(0.85)Ni_(0.15)(111).The signature of moré lattices has not been observed in either the low-energy electron diffraction patterns or the Fermi surface map within experimental resolution,possibly due to different Cu and Ni contents in the substrates enhancing the different couplings between the substrate and the first/second layers and hindering the formation of a quasiperiodic structure.展开更多
DEAR EDITOR,The Laosicheng site in Yongshun County,Hunan Province,China,plays an important role in elucidating the animal population composition of the region prior to the middle Qing Dynasty(approximately 300 years a...DEAR EDITOR,The Laosicheng site in Yongshun County,Hunan Province,China,plays an important role in elucidating the animal population composition of the region prior to the middle Qing Dynasty(approximately 300 years ago).This site has yielded a substantial number of animal bones,11960 of which have been identified to the species level,serving as direct evidence of ancient animal populations(Hunan Provincial Institute of Cultural Relics and Archaeology,2018).展开更多
Due to the selective absorption of light and the existence of a large number of floating media in sea water, underwater images often suffer from color casts and detail blurs. It is therefore necessary to perform color...Due to the selective absorption of light and the existence of a large number of floating media in sea water, underwater images often suffer from color casts and detail blurs. It is therefore necessary to perform color correction and detail restoration. However,the existing enhancement algorithms cannot achieve the desired results. In order to solve the above problems, this paper proposes a multi-stream feature fusion network. First, an underwater image is preprocessed to obtain potential information from the illumination stream, color stream and structure stream by histogram equalization with contrast limitation, gamma correction and white balance, respectively. Next, these three streams and the original raw stream are sent to the residual blocks to extract the features. The features will be subsequently fused. It can enhance feature representation in underwater images. In the meantime, a composite loss function including three terms is used to ensure the quality of the enhanced image from the three aspects of color balance, structure preservation and image smoothness. Therefore, the enhanced image is more in line with human visual perception.Finally, the effectiveness of the proposed method is verified by comparison experiments with many stateof-the-art underwater image enhancement algorithms. Experimental results show that the proposed method provides superior results over them in terms of MSE,PSNR, SSIM, UIQM and UCIQE, and the enhanced images are more similar to their ground truth images.展开更多
Background Sleep disturbance is a common comorbidity of major depressive disorder(MDD).However,network homogeneity(NH)changes of the default mode network(DMN)in MDD with sleep disturbances are unclear.Aims The purpose...Background Sleep disturbance is a common comorbidity of major depressive disorder(MDD).However,network homogeneity(NH)changes of the default mode network(DMN)in MDD with sleep disturbances are unclear.Aims The purpose of this study was to probe the abnormal NH in the DMN in MDD with sleep disturbances and to reveal the differences between MDD with or without sleep disturbances.Methods Twenty-four patients with MDD and sleep disturbances(Pa_s),33 patients with MDD without sleep disturbances(Pa_ns)and 32 healthy controls(HCs)were recruited in this study.Resting-state functional imaging data were analysed using NH.Results Compared with Pa_ns and HCs,Pa_s showed decreased NH in the left superior medial prefrontal cortex and increased NH in the right precuneus.There was a negative correlation between NH in the left superior medial prefrontal cortex and sleep disturbances(r=−0.42,p=0.001)as well as a positive correlation between NH in the right precuneus and sleep disturbances(r=0.41,p=0.002)in patients with MDD.Conclusions MDD with sleep disturbances is associated with abnormal NH in the DMN,which could differentiate pa_s from pa_ns.The DMN may play a crucial role in the neurobiological mechanisms of MDD with sleep disturbances.展开更多
文摘BACKGROUND: Secondary lymphedema is one of the common complications after malignant tumor surgery. It is a chronic and complex disease. Once lymphedema occurs, there will be discomfort such as limb swelling, pain, numbness and tension, which will eventually lead to changes in the appearance of the affected limb and will seriously affect the quality of life and require lifelong treatment and psychosocial support. This study investigated the current situation of stigma and alexithymia in patients with lymphedema, and discussed the impact of alexithymia on stigma in patients with lymphedema. AIMS: To understand the current situation of stigma and alexithymia in patients with lymphedema, and to analyze the influence of alexithymia on stigma. METHODS: 195 patients with lymphedema in a hospital were selected by convenient sampling. General information questionnaire, Toronto Alexithymia Scale and social impact scale were used to investigate respectively, to study the general situation, stigma and alexithymia of the respondents. RESULTS: The results showed that the total score of stigma in 195 patients with lymphedema was (60.36 ± 11.08), and the total score of alexithymia was (56.53 ± 8.43). Multiple linear regression analysis showed that alexithymia and family relationship were the influencing factors of stigma in patients with lymphedema. CONCLUSIONS: The patients with lymphedema have obvious stigma, and alexithymia and family relationship are the influencing factors.
文摘Objective: To explore the pre-treatment and efficacy analysis of comprehensive anti-inflammatory treatment for lymphedema in patients with irritating contact dermatitis. Method: Convenience sampling method was used to observe the skin of 160 patients with upper limb lymphedema admitted to the lymphedema outpatient department of our hospital. They were divided into an observation group (80 cases) and a control group (80 cases), and both groups received a course of comprehensive anti-inflammatory treatment (20 treatments). The control group received routine skin care;On the basis of the control group, the observation group received pre-treatment of the affected limb skin: Laofuzi herbal ointment was applied externally to the prone areas of irritating contact dermatitis (such as the upper arm, inner forearm, and cubital fossa). Result: The incidence of irritating contact dermatitis in the observation group was significantly lower than that in the control group (P 0.05). Patients in the observation group felt significantly better in terms of comfort, skin moisture, and itching relief after being wrapped with low elasticity bandages than those in the control group (P Conclusion: Preventive treatment can effectively reduce the incidence of irritating contact dermatitis, prolong the time of stress treatment, thereby increasing efficacy and improving patient compliance.
基金Project supported by the National Natural Science Foundation of China(Grant No.52261037)self-deployed Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(Grant No.E055B002)+2 种基金the Project of Baotou City Science and Technology(Grant No.XM2022BT04)the Key Research Program of the Chinese Academy of Sciences(Grant No.ZDRW-CN-2021-3)the Key Research Project of Jiangxi Province(Grant No.20203ABC28W006)。
文摘As the channel for grain boundary diffusion(GBD)in Nd–Fe–B magnets,grain boundary(GB)phases have a very important effect on GBD.As doping elements that are commonly used to regulate the GB phases in Nd–Fe–B sintered magnets,the influences of Ga and Zr on GBD were investigated in this work.The results show that the Zr-doped magnet has the highest coercivity increment(7.97 kOe)by GBD,which is almost twice that of the Ga-doped magnet(4.32 kOe)and the magnet without Ga and Zr(3.24 kOe).Microstructure analysis shows that ZrB_(2)formed in the Zr-doped magnet plays a key role in increasing the diffusion depth.A continuous diffusion channel in the magnet can form because of the presence of ZrB_(2).ZrB_(2)can also increase the defect concentration in GB phases,which can facilitate GBD.Although Ga can also improve the diffusion depth,its effect is not very obvious.The micromagnetic simulation based on the experimental results also proves that the distribution of Tb in the Zr-doped magnet after GBD is beneficial to coercivity.This study reveals that the doping elements Ga and Zr in Nd–Fe–B play an important role in GBD,and could provide a new perspective for researchers to improve the effects of GBD.
基金This work is funded by the Magnetic Resonance Union of the Chinese Academy of Sciences(Grant No.2021gzl002)the International Partnership Program of Chinese Academy of Sciences(Grant No.182111KYSB20210014)+1 种基金the National Science Foundation of China(Grant No.52293423,Grant No.52277031)the Research and Development of Key Technologies and Equipment for Major Science and Technology Infrastructure of Development and Reform Commission of Shenzhen Municipality,China(Grant No.ZDKJ20190305002).
文摘The relatively fragile low-temperature stability of cryogen-free superconducting magnetic resonance imaging(MRI)magnets requires the careful management of exogenous heat sources.A strongly shielded gradient magnetic field is important for the optimal operation of cryogen-free MRI systems.In this study,we present an enhanced shielding method incorporating a regionalized stray field constraining strategy.By optimizing the constraint parameters,we could develop engineering-feasible gradient coil schemes without increasing system complexity but with the stray field intensity reduced by half.In real measurement in an integrated MRI system,the developed gradient assembly demonstrated good performance and supported to output images of excellent quality.Our findings suggested that the proposed method could potentially form a useful design paradigm for cryogen-free MRI magnets.
基金financial support of the National Natural Science Foundation of China(Nos.52130110 and U22A20189)the Research Fund of the State Key Laboratory of Solidification Processing(No.2023-TS-10)。
文摘The microstructure characteristics and strengthening mechanism of Inconel738LC(IN-738LC) alloy prepared by using induction-assisted directed energy deposition(IDED) were elucidated through the investigation of samples subjected to IDED under 1050℃ preheating with and without hot isostatic pressing(HIP,1190℃,105 MPa,and 3 h).Results show that the as-deposited sample mainly consisted of epitaxial columnar crystals and inhomogeneously distributed γ’ phases in interdendritic and dendritic core regions.After HIP,grain morphology changed negligibly,whereas the size of the γ’ phase became increasingly even.After further heat treatment(HT,1070℃,2 h + 845℃,24 h),the γ’ phase in the as-deposited and HIPed samples presented a bimodal size distribution,whereas that in the as-deposited sample showed a size that remained uneven.The comparison of tensile properties revealed that the tensile strength and uniform elongation of the HIP + HTed sample increased by 5% and 46%,respectively,due to the synergistic deformation of bimodal γ’phases,especially large cubic γ’ phases.Finally,the relationship between phase transformations and plastic deformations in the IDEDed sample was discussed on the basis of generalized stability theory in terms of the trade-off between thermodynamics and kinetics.
基金supported by the National Natural Science Funds of China(Grant number 22278016)Science and technology planning project of Yunnan Precious Metals Laboratory(Grant number YPML-2023050204)。
文摘Achieving composition tunability and structure editability of nanoalloys with high level strain may be an efficient strategy to remarkably boost catalytic performance toward oxygen evolution reaction(OER)in acidic water oxidation.Herein,lotus root-like RuIr alloys with native micro-strain were constructed by an epitaxial growth of Ru-richened hcp-(0001)branches on Ir-richened fcc-(111)seeds using a polyol thermal synthesis strategy.The resultant Ru_(60)Ir_(40) alloy shows an OER overpotential of 197 mV at 10 mA cm^(-2) and a Tafel slope of 46.59 mV dec^(-1),showing no obvious activity decay for 80 h continuous chronopotentiometry test in 0.5 M H_(2)SO_(4).The related characterizations including X-ray absorption fine structure(XAFS)spectroscopy and density functional theory(DFT)calculations show that that the remarkably improved activity of the lotus root-like alloy can be attributed to the(0001)facet-triggered strain,which can efficiently optimize the electronic band structure of the active metal and the weakening of the chemisorption of oxygen-containing substances to boost OER electrocatalysis.Therefore,this work provides a new strategy to designing a class of advanced electrocatalysts with high strain using diverse nanostructures as building materials for carbon-free clean energy conversion systems.
基金supported by the Science and Technology Special Plan Project from China Minmetals Group (No.2020ZXA01)the International Exchange and Growth Program for Young Teachers (No.QNXM20220061)the National Key Research and Development Program of China (No.2022YFC2906100).
文摘Boron is an important industrial raw material often sourced from minerals containing different compounds that cocrystallize,which makes it difficult to separate the mineral phases through conventional beneficiation.This study proposed a new treatment called flash reduction-melting separation(FRMS)for boron-bearing iron concentrates.In this method,the concentrates were first flash-reduced at the temperature under which the particles melt,and the slag and the reduced iron phases disengaged at the particle scale.Good reduc-tion and melting effects were achieved above 1550℃.The B_(2)O_(3) content in the separated slag was over 18wt%,and the B content in the iron was less than 0.03wt%.The proposed FRMS method was tested to investigate the effects of factors such as ore particle size and tem-perature on the reduction and melting steps with and without pre-reducing the raw concentrate.The mineral phase transformation and morphology evolution in the ore particles during FRMS were also comprehensively analyzed.
基金supported by the National Natural Science Foundation of China(No.22209035)the Major Science and Technology Projects of Yunnan Province(No.202302AH360001)the Natural Science Foundation of Hebei Province(No.E2020202091).
文摘RuO_(2) has been considered a potential alternative to commercial IrO_(2) for the oxygen evolution reaction(OER)due to its superior intrinsic activity.However,its inherent structure dissolution in acidic environments restricts its commercial applications.In this study,we report a novel Pd-doped ruthenium oxide(Pd–RuO_(2))nanosheet catalyst that exhibits improved activity and stability through a synergistic effect of Pd modulation of Ru electronic structure and the two-dimensional structure.The catalyst exhibits excellent performance,achieving an overpotential of only 204 mVat a current density of 10 mA cm^(-2).Impressively,after undergoing 8000 cycles of cyclic voltammetry testing,the overpotential merely decreased by 5 mV.The PEM electrolyzer with Pd0.08Ru0.92O_(2) as an anode catalyst survived an almost 130 h operation at 200 mA cm^(-2).To elucidate the underlying mechanisms responsible for the enhanced stability,we conducted an X-ray photoelectron spectroscopy(XPS)analysis,which reveals that the electron transfer from Pd to Ru effectively circumvents the over-oxidation of Ru,thus playing a crucial role in enhancing the catalyst's stability.Furthermore,density functional theory(DFT)calculations provide compelling evidence that the introduction of Pd into RuO_(2) effectively modulates electron correlations and facilitates the electron transfer from Pd to Ru,thereby preventing the overoxidation of Ru.Additionally,the application of the two-dimensional structure effectively inhibited the aggregation and growth of nanoparticles,further bolstering the structural integrity of the catalyst.
基金supported by the National Natural Science Foundation of China(Grant No.42372310).
文摘Crack propagation in brittle material is not only crucial for structural safety evaluation,but also has a wideranging impact on material design,damage assessment,resource extraction,and scientific research.A thorough investigation into the behavior of crack propagation contributes to a better understanding and control of the properties of brittle materials,thereby enhancing the reliability and safety of both materials and structures.As an implicit discrete elementmethod,the Discontinuous Deformation Analysis(DDA)has gained significant attention for its developments and applications in recent years.Among these developments,the particle DDA equipped with the bonded particle model is a powerful tool for predicting the whole process of material from continuity to failure.The primary objective of this research is to develop and utilize the particle DDAtomodel and understand the complex behavior of cracks in brittle materials under both static and dynamic loadings.The particle DDA is applied to several classical crack propagation problems,including the crack branching,compact tensile test,Kalthoff impact experiment,and tensile test of a rectangular plate with a hole.The evolutions of cracks under various stress or geometrical conditions are carefully investigated.The simulated results are compared with the experiments and other numerical results.It is found that the crack propagation patterns,including crack branching and the formation of secondary cracks,can be well reproduced.The results show that the particle DDA is a qualified method for crack propagation problems,providing valuable insights into the fracture mechanism of brittle materials.
基金National Natural Science Foundation of China,No.81970550,No.82070613 and No.82370638Natural Science Foundation of Hunan Province,China,No.2021JJ31067 and No.2021JJ41048+1 种基金Hunan innovative province construction project,No.2023JJ10095Innovative Talented Project of Hunan province,China,No.2022RC1212.
文摘BACKGROUND Acute decompensation(AD)of cirrhosis is associated with high short-term mortality,mainly due to the development of acute-on-chronic liver failure(ACLF).Thus,there is a need for biomarkers for early and accurate identification of AD patients with high risk of development of ACLF and mortality.Soluble triggering receptor expressed on myeloid cells-1(sTREM-1)is released from activated innate immune cells and correlated with various inflammatory processes.AIM To explore the prognostic value of sTREM-1 in patients with AD of cirrhosis.METHODS A multicenter prospective cohort of 442 patients with cirrhosis hospitalized for AD was divided into a study cohort(n=309)and validation cohort(n=133).Demographic and clinical data were collected,and serum sTREM-1 was measured at admission.All enrolled patients were followed-up for at least 1 year.RESULTS In patients with AD and cirrhosis,serum sTREM-1 was an independent prognosis predictor for 1-year survival and correlated with liver,coagulation,cerebral and kidney failure.A new prognostic model of AD(P-AD)incorporating sTREM-1,blood urea nitrogen(BUN),total bilirubin(TBil),international normalized ratio(INR)and hepatic encephalopathy grades was established and performed better than the model for end-stage liver disease(MELD),MELD-sodium(MELD-Na),chronic liver failure-consortium(CLIF-C)ACLF and CLIF-C AD scores.Additionally,sTREM-1 was increased in ACLF and predicted the development of ACLF during first 28-d follow-up.The ACLF risk score incorporating serum sTREM-1,BUN,INR,TBil and aspartate aminotransferase levels was established and significantly superior to MELD,MELD-Na,CLIF-C ACLF,CLIF-C AD and P-AD in predicting risk of ACLF development.CONCLUSION Serum sTREM-1 is a promising prognostic biomarker for ACLF development and mortality in patients with AD of cirrhosis.
基金supported by National Natural Science Foundation of China(Nos.52037004 and 52177148)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_1449).
文摘Dielectric barrier discharge(DBD)is considered as a promising technique to produce large volume uniform plasma at atmospheric pressure,and the dielectric barrier layer between the electrodes plays a key role in the DBD processes and enhancing discharge uniformity.In this work,the uniformity and discharge characteristics of the nanosecond(ns)pulsed DBD with dielectric barrier layers made of alumina,quartz glass,polycarbonate(PC),and polypropylene(PP)are investigated via discharge image observation,voltage-current waveform measurement and optical emission spectral diagnosis.Through analyzing discharge image by gray value standard deviation method,the discharge uniformity is quantitatively calculated.The effects of the space electric field intensity,the electron density(Ne),and the space reactive species on the uniformity are studied with quantifying the gap voltage Ug and the discharge current Ig,analyzing the recorded optical emission spectra,and simulating the temporal distribution of Ne with a one-dimensional fluid model.It is found that as the relative permittivity of the dielectric materials increases,the space electric field intensity is enhanced,which results in a higher Ne and electron temperature(Te).Therefore,an appropriate value of space electric field intensity can promote electron avalanches,resulting in uniform and stable plasma by the merging of electron avalanches.However,an excessive value of space electric field intensity leads to the aggregation of space charges and the distortion of the space electric field,which reduce the discharge uniformity.The surface roughness and the surface charge decay are measured to explain the influences of the surface properties and the second electron emission on the discharge uniformity.The results in this work give a comprehensive understanding of the effect of the dielectric materials on the DBD uniformity,and contribute to the selection of dielectric materials for DBD reactor and the realization of atmospheric pressure uniform,stable,and reactive plasma sources.
基金supported by the National Natural Science Foundation of China under Grant 62177029the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX21_0740),China.
文摘Visual object tracking plays a crucial role in computer vision.In recent years,researchers have proposed various methods to achieve high-performance object tracking.Among these,methods based on Transformers have become a research hotspot due to their ability to globally model and contextualize information.However,current Transformer-based object tracking methods still face challenges such as low tracking accuracy and the presence of redundant feature information.In this paper,we introduce self-calibration multi-head self-attention Transformer(SMSTracker)as a solution to these challenges.It employs a hybrid tensor decomposition self-organizing multihead self-attention transformermechanism,which not only compresses and accelerates Transformer operations but also significantly reduces redundant data,thereby enhancing the accuracy and efficiency of tracking.Additionally,we introduce a self-calibration attention fusion block to resolve common issues of attention ambiguities and inconsistencies found in traditional trackingmethods,ensuring the stability and reliability of tracking performance across various scenarios.By integrating a hybrid tensor decomposition approach with a self-organizingmulti-head self-attentive transformer mechanism,SMSTracker enhances the efficiency and accuracy of the tracking process.Experimental results show that SMSTracker achieves competitive performance in visual object tracking,promising more robust and efficient tracking systems,demonstrating its potential to providemore robust and efficient tracking solutions in real-world applications.
文摘The emergence of the internet of things has promoted wireless communication’s evolution towards multi-band and multi-area utilization.Notably,forthcoming sixth-generation(6G)communication standards,incorporating terahertz(THz)frequencies alongside existing gigahertz(GHz)modes,drive the need for a versatile multi-band electromagnetic wave(EMW)absorbing and shielding material.This study introduces a pivotal advance via a new strategy,called ultrafast laser-induced thermal-chemical transformation and encapsulation of nanoalloys(LITENs).Employing multivariate metal-organic frameworks,this approach tailors a porous,multifunctional graphene-encased magnetic nanoalloy(GEMN).By fine-tuning pulse laser parameters and material components,the resulting GEMN excels in low-frequency absorption and THz shielding.GEMN achieves a breakthrough of minimum reflection loss of−50.6 dB in the optimal C-band(around 4.98 GHz).Computational evidence reinforces GEMN’s efficacy in reducing radar cross sections.Additionally,GEMN demonstrates superior electromagnetic interference shielding,reaching 98.92 dB under THz band(0.1–2 THz),with the mean value result of 55.47 dB.These accomplishments underscore GEMN’s potential for 6G signal shielding.In summary,LITEN yields the remarkable EMW controlling performance,holding promise in both GHz and THz frequency domains.This contribution heralds a paradigm shift in EM absorption and shielding materials,establishing a universally applicable framework with profound implications for future pursuits.
基金Project supported by the National Key R&D Program of China (Grant Nos. 2022YFB3608000 and 2022YFA1204900)the National Natural Science Foundation of China (Grant Nos. 12222413 and 12074205)+2 种基金the Natural Science Foundation of Shanghai (Grant Nos. 23ZR1482200 and 22ZR1473300)the Natural Science Foundation of Zhejiang Province (Grant No. LQ21A040004)the funding of Ningbo University (Grant No. LJ2024003)。
文摘Twisted bilayer graphene(TBG) has been extensively studied because of its novel physical properties and potential application in electronic devices.Here we report the synthesis and characterization of 300 TBG naturally grown on Cu_(0.75)Ni_(0.25)(111) film and investigate the electronic structure by angle-resolved photoemission spectroscopy.Compared with other substrates,our TBG with a wafer scale is acquired with a shorter growth time.The Fermi velocity and energy gap of Dirac cones of TBG are comparable with those of a monolayer on Cu_(0.85)Ni_(0.15)(111).The signature of moré lattices has not been observed in either the low-energy electron diffraction patterns or the Fermi surface map within experimental resolution,possibly due to different Cu and Ni contents in the substrates enhancing the different couplings between the substrate and the first/second layers and hindering the formation of a quasiperiodic structure.
基金supported by the National Natural Science Foundation of China(41925009,32100488)National Key R&D Program of China(2022YFE0203800)+1 种基金Chinese Academy of Sciences(YSBR-019)New Cornerstone Science Foundation through the XPLORER PRIZE。
文摘DEAR EDITOR,The Laosicheng site in Yongshun County,Hunan Province,China,plays an important role in elucidating the animal population composition of the region prior to the middle Qing Dynasty(approximately 300 years ago).This site has yielded a substantial number of animal bones,11960 of which have been identified to the species level,serving as direct evidence of ancient animal populations(Hunan Provincial Institute of Cultural Relics and Archaeology,2018).
基金supported by the national key research and development program (No.2020YFB1806608)Jiangsu natural science foundation for distinguished young scholars (No.BK20220054)。
文摘Due to the selective absorption of light and the existence of a large number of floating media in sea water, underwater images often suffer from color casts and detail blurs. It is therefore necessary to perform color correction and detail restoration. However,the existing enhancement algorithms cannot achieve the desired results. In order to solve the above problems, this paper proposes a multi-stream feature fusion network. First, an underwater image is preprocessed to obtain potential information from the illumination stream, color stream and structure stream by histogram equalization with contrast limitation, gamma correction and white balance, respectively. Next, these three streams and the original raw stream are sent to the residual blocks to extract the features. The features will be subsequently fused. It can enhance feature representation in underwater images. In the meantime, a composite loss function including three terms is used to ensure the quality of the enhanced image from the three aspects of color balance, structure preservation and image smoothness. Therefore, the enhanced image is more in line with human visual perception.Finally, the effectiveness of the proposed method is verified by comparison experiments with many stateof-the-art underwater image enhancement algorithms. Experimental results show that the proposed method provides superior results over them in terms of MSE,PSNR, SSIM, UIQM and UCIQE, and the enhanced images are more similar to their ground truth images.
基金This study was supported by grants from the National Natural Science Foundation of China(Grant numbers:82171508 and 82071507).
文摘Background Sleep disturbance is a common comorbidity of major depressive disorder(MDD).However,network homogeneity(NH)changes of the default mode network(DMN)in MDD with sleep disturbances are unclear.Aims The purpose of this study was to probe the abnormal NH in the DMN in MDD with sleep disturbances and to reveal the differences between MDD with or without sleep disturbances.Methods Twenty-four patients with MDD and sleep disturbances(Pa_s),33 patients with MDD without sleep disturbances(Pa_ns)and 32 healthy controls(HCs)were recruited in this study.Resting-state functional imaging data were analysed using NH.Results Compared with Pa_ns and HCs,Pa_s showed decreased NH in the left superior medial prefrontal cortex and increased NH in the right precuneus.There was a negative correlation between NH in the left superior medial prefrontal cortex and sleep disturbances(r=−0.42,p=0.001)as well as a positive correlation between NH in the right precuneus and sleep disturbances(r=0.41,p=0.002)in patients with MDD.Conclusions MDD with sleep disturbances is associated with abnormal NH in the DMN,which could differentiate pa_s from pa_ns.The DMN may play a crucial role in the neurobiological mechanisms of MDD with sleep disturbances.
