BACKGROUND Low anterior resection syndrome(LARS)severely impairs patient postoperative quality of life,especially major LARS.However,there are few tools that can accurately predict major LARS in clinical practice.AIM ...BACKGROUND Low anterior resection syndrome(LARS)severely impairs patient postoperative quality of life,especially major LARS.However,there are few tools that can accurately predict major LARS in clinical practice.AIM To develop a machine learning model using preoperative and intraoperative factors for predicting major LARS following laparoscopic surgery of rectal cancer in Chinese populations.METHODS Clinical data and follow-up information of patients who received laparoscopic anterior resection for rectal cancer from two medical centers(one discovery cohort and one external validation cohort)were included in this retrospective study.For the discovery cohort,the machine learning prediction algorithms were developed and internally validated.In the external validation cohort,we evaluated the trained model using various performance metrics.Further,the clinical utility of the model was tested by decision curve analysis.RESULTS Overall,1651 patients were included in the present study.Anastomotic height,neoadjuvant therapy,diverting stoma,body mass index,clinical stage,specimen length,tumor size,and age were the risk factors associated with major LARS.They were used to construct the machine learning model to predict major LARS.The trained random forest(RF)model performed with an area under the curve of 0.852 and a sensitivity of 0.795(95%CI:0.681-0.877),a specificity of 0.758(95%CI:0.671-0.828),and Brier score of 0.166 in the external validation set.Compared to the previous preoperative LARS score model,the current model exhibited superior predictive performance in predicting major LARS in our cohort(accuracy of 0.772 for the RF model vs 0.355 for the preoperative LARS score model).CONCLUSION We developed and validated a robust tool for predicting major LARS.This model could potentially be used in the clinic to identify patients with a high risk of developing major LARS and then improve the quality of life.展开更多
The Cr-plated coating inside a gun barrel can effectively improve the barrel’s erosion resistance and thus increase the service life.However,due to the cyclic thermal load caused by high-temperature gunpowder,micro-e...The Cr-plated coating inside a gun barrel can effectively improve the barrel’s erosion resistance and thus increase the service life.However,due to the cyclic thermal load caused by high-temperature gunpowder,micro-element damage tends to occur within the Cr coating/steel substrate interface,leading to a gradual deterioration in macro-mechanical properties for the material in the related region.In order to mimic this cyclic thermal load and,thereby,study the thermal erosion behavior of the Cr coating on the barrel’s inner wall,a laser emitter is utilized in the current study.With the help of in-situ tensile test and finite element simulation results,a shear stress distribution law of the Cr coating/steel substrate and a change law of the interface ultimate shear strength are identified.Studies have shown that the Cr coating/steel substrate interface’s ultimate shear strength has a significant weakening effect due to increasing temperature.In this study,the interfacial ultimate shear strength decreases from 2.57 GPa(no erosion)to 1.02 GPa(laser power is 160 W).The data from this experiment is employed to establish a Cr coating/steel substrate interface shear damage model.And this model is used to predict the flaking process of Cr coating by finite element method.The simulation results show that the increase of coating crack spacing and coating thickness will increase the service life of gun barrel.展开更多
An increase in the use of the gun barrel will cause wear of the inner wall,which reduces the muzzle velocity and the spin rate of the projectile.The off-bore flight attitude and trajectory of the projectile also chang...An increase in the use of the gun barrel will cause wear of the inner wall,which reduces the muzzle velocity and the spin rate of the projectile.The off-bore flight attitude and trajectory of the projectile also change,affecting the shooting power and the accuracy.Exterior ballistic data of a high-speed spinning projectile are required to study the performance change.Therefore,based on the barrel’s accelerated life test,the whole process of projectile shooting is reproduced using numerical simulation technology,and key information on the ballistic performance change at each shooting stage are acquired.Studies have shown that in the later stages of barrel shooting,the accuracy of shooting has not decreased significantly.However,it is found that the angle of attack of the projectile increases as the wear of the barrel increases.The maximum angle of attack reaches 0.106 rad when the number of shots reaches 4300.Meanwhile,elliptical bullet hole has appeared on the target at this shooting stage.Through combining external ballistic theory with simulation results,the primary reason of this phenomenon is found to be a significant decrease in the muzzle spin rate of the projectile.At the end of the barrel life,the projectile muzzle spin rate is 57.5%lower than that of a barrel without wear.展开更多
Combining with electrospray ionization(ESI)mass spectrometry,infrared photodissociation(IRPD)spectroscopy is a powerful method to study structures of cluster ions in the gas phase.In this paper,infrared photodissociat...Combining with electrospray ionization(ESI)mass spectrometry,infrared photodissociation(IRPD)spectroscopy is a powerful method to study structures of cluster ions in the gas phase.In this paper,infrared photodissociation spectrum of Pro_4H~+in the range of 2700–3600 cm 1was obtained experimentally.Both theoretically predicted spectra of the two most stable isomers of Pro4^(-1)and Pro4^(-2)obtained at the level of M062X/6-31+G(d,p)are in good consistent with the experimental results.The two isomers have similar structures and close energies.Both of them only consist of zwitterionic units,indicating the strong salt-bridged interactions inside the clusters.And the calculated collision cross section(ccs)of Pro4-1 is found to be very close to the experimental result previously reported.展开更多
We know that the Box dimension of f（x） ∈ C^1[0,1] is 1. In this paper, we prove that the Box dimension of continuous functions with bounded variation is still 1. Furthermore, Box dimension of Weyl fractional integr...We know that the Box dimension of f（x） ∈ C^1[0,1] is 1. In this paper, we prove that the Box dimension of continuous functions with bounded variation is still 1. Furthermore, Box dimension of Weyl fractional integral of above function is also 1.展开更多
First mirror(FM)cleaning,using radio frequency(RF)plasma,has been proposed to recover FM reflectivity in nuclear fusion reactors such as the International Thermonuclear Experimental Reactor(ITER).To investigate the in...First mirror(FM)cleaning,using radio frequency(RF)plasma,has been proposed to recover FM reflectivity in nuclear fusion reactors such as the International Thermonuclear Experimental Reactor(ITER).To investigate the influence of simultaneous cleaning of two mirrors on mirror cleaning efficiency and uniformity,experiments involving single-mirror cleaning and dual-mirror cleaning were conducted using RF capacitively coupled plasma in the laboratory.For the test and simultaneous cleaning of two mirrors,the FM and second mirror(SM),both measuring 110 mm×80 mm,were placed inside the first mirror unit(FMU).They were composed of 16 mirror samples,each with a dimension of 27.5 mm×20 mm.These mirror samples consist of a titanium-zirconium-molybdenum alloy substrate,a 500 nm Mo intermediate layer and a 30 nm Al_(2)O_(3) surface coating as a proxy for Be impurities.The cleaning of a single first mirror(SFM)and the simultaneous cleaning of the FM and SM(DFM and DSM)lasted for 9 h using Ar plasma at a pressure of 1 Pa.The total reflectivity of mirror samples on the DSM did not fully recover and varied with location,with a self-bias of−140 V.With a self-bias of−300 V,the total reflectivity of mirror samples on the SFM and DFM was fully recovered.The energy dispersive spectrometer results demonstrated that the Al_(2)O_(3) coating had been completely removed from these mirror samples.However,the mass loss of each mirror sample on the SFM and DFM before and after cleaning varied depending on its location,with higher mass loss observed for mirror samples located in the corners and lower loss for those in the center.Compared with SM cleaning,the simultaneous cleaning of two mirrors reduced the difference between the highest and lowest mass loss.Furthermore,this mass loss for the mirror samples of the DFM facing the DSM was increased.This indicated that mirror samples cleaned face to face in the FMU simultaneously could influence each other,highlighting the need for special attention in future studies.展开更多
Skin is one of the most vulnerable tissues,but there is a lack of injectable bioactive hydrogel dressings,which possess high strength,antiswelling capacity,and wet tissue adhesiveness,but also a rapid gelling process ...Skin is one of the most vulnerable tissues,but there is a lack of injectable bioactive hydrogel dressings,which possess high strength,antiswelling capacity,and wet tissue adhesiveness,but also a rapid gelling process to enable rapid hemostasis,sutureless wound closure,and scarless healing of infected skin wounds[1e5].A new injectable,antibacterial,and multifunctional hydrogel dressings based on poly(citric acid-co-polyethylene glycol)-g-dopamine(PCPD)and amino-terminated Pluronic F127(APF)mi-celles loaded with astragaloside IV(AS)was developed for this pur-pose,as shown in Fig.1A[6].展开更多
Traditional vortex beam parameter determination methods are all designed for aberration-free vortex beams.In the case of aberrations and turbulence,they tend to struggle in mutual restraint between phase recovery and ...Traditional vortex beam parameter determination methods are all designed for aberration-free vortex beams.In the case of aberrations and turbulence,they tend to struggle in mutual restraint between phase recovery and topological charge(TC)detection.Most recent methods depend on complex interferometric setups and precise phase singularity localization.An iterative virtual Moiréreconstruction(IVMR)technique is proposed based on the blind conformal mapping,achieving simultaneous demodulation of TC and phase from a single-frame aberrated interferogram,not needing precise phase singularity positioning.展开更多
Background:The association between dietary sodium intake and blood pressure variability(BPV)in hypertensive patients remains unclear.The objective of this study was to demonstrate whether dietary sodium intake is a pr...Background:The association between dietary sodium intake and blood pressure variability(BPV)in hypertensive patients remains unclear.The objective of this study was to demonstrate whether dietary sodium intake is a predictor of elevated BPV in Chinese patients with hypertension.Methods:A total of 235 patients with essential hypertension were enrolled in the Department of Cardiology,Chinese People’s Liberation Army(PLA)General Hospital in 2018 to 2019,all of whom underwent 24-h ambulatory blood pressure monitoring.BPV was calculated as the standard deviation(SD),coefficient of variation(CV),variation independent of mean(VIM)of blood pressure measurements,respectively,and divided into diurnal systolic BPV(SBPV),diurnal diastolic BPV(DBPV),nocturnal SBPV,and nocturnal DBPV.24-h urine samples were collected to measure 24-h urine sodium excretion,which represents dietary sodium intake.The relationship between dietary sodium intake and BPV was analyzed by using Spearman correlations and multiple linear regression analysis.Results:Nocturnal SBPV-SD,CV,VIM,and nocturnal DBPV-SD in the high urine sodium excretion group were significantly higher than those in the medium and low urine sodium excretion groups,whereas diurnal SBPV-SD,CV,VIM,diurnal DBPV-SD,CV,VIM,and nocturnal DBPV-CV,VIM were not.Using the Spearman correlation analysis,we found a linear correlation between 24-h urine sodium excretion and nocturnal SBPV-SD,CV,VIM(SD,r=0.22,P=0.001;CV,r=0.17,P=0.009;VIM,r=0.16,P=0.020),nocturnal DBPV-SD(r=0.21,P=0.001),respectively.After further adjusting for confounding factors by multiple linear regression,the positive correlations remained between 24-h urine sodium excretion and nocturnal SBPV-SD,CV,VIM(SD,β=0.224,P<0.001;CV,β=0.211,P=0.001;VIM,β=0.213,P=0.001),nocturnal DBPV(SD,β=0.215,P=0.001),respectively.Conclusions:Dietary sodium intake is associated with nocturnal SBPV in Chinese patients with hypertension.展开更多
Naturally existing in-plane hyperbolic polaritons and the associated optical topological transitions,which avoid the nano-structuring to achieve hyperbolicity,can outperform their counterparts in artificial metasurfac...Naturally existing in-plane hyperbolic polaritons and the associated optical topological transitions,which avoid the nano-structuring to achieve hyperbolicity,can outperform their counterparts in artificial metasurfaces.Such plasmon polaritons are rare,but experimentally revealed recently in WTe_(2)van der Waals thin films.Different from phonon polaritons,hyperbolic plasmon polaritons originate from the interplay of free carrier Drude response and interband transitions,which promise good intrinsic tunability.However,tunable in-plane hyperbolic plasmon polariton and its optical topological transition of the isofrequency contours to the elliptic topology in a natural material have not been realized.Here we demonstrate the tuning of the optical topological transition through Mo doping and temperature.The optical topological transition energy is tuned over a wide range,with frequencies ranging from 429 cm^(−1)(23.3 microns)for pure WTe_(2)to 270 cm^(−1)(37.0 microns)at the 50%Mo-doping level at 10 K.Moreover,the temperature-induced blueshift of the optical topological transition energy is also revealed,enabling active and reversible tuning.Surprisingly,the localized surface plasmon resonance in skew ribbons shows unusual polarization dependence,accurately manifesting its topology,which renders a reliable means to track the topology with far-field techniques.Our results open an avenue for reconfigurable photonic devices capable of plasmon polariton steering,such as canaling,focusing,and routing,and pave the way for low-symmetry plasmonic nanophotonics based on anisotropic natural materials.展开更多
Nowadays,end fitting corrosion reduces the mechanical strength and flashover voltage of insulators,forming a huge threat to high‐voltage direct current transmission lines.At present,the parameters of electrolytic cor...Nowadays,end fitting corrosion reduces the mechanical strength and flashover voltage of insulators,forming a huge threat to high‐voltage direct current transmission lines.At present,the parameters of electrolytic corrosion inhibition measures are selected based on the premise of the constant annual corrosion rate.However,with the development of corrosion,corrosion products accumulate on the insulator surface,which may impact the corrosion rate.In order to clarify the influence of corrosion products,this work studied how corrosion products influence the corrosion rate from the corrosion phenomenon,corrosion current,feature and formation of corrosion products.The results showed that corrosion products of iron and zinc were excellent in adhesion on the insulator surface and could not be cleaned by rain,which was able to increase the corrosion rate.In future,in the selection of the quality of the zinc ring bonded on insulator fittings,there will be a demand to consider the influence of corrosion products on the corrosion rate.展开更多
基金Supported by the National Natural Science Foundation of China,No.82173368 and 81903047.
文摘BACKGROUND Low anterior resection syndrome(LARS)severely impairs patient postoperative quality of life,especially major LARS.However,there are few tools that can accurately predict major LARS in clinical practice.AIM To develop a machine learning model using preoperative and intraoperative factors for predicting major LARS following laparoscopic surgery of rectal cancer in Chinese populations.METHODS Clinical data and follow-up information of patients who received laparoscopic anterior resection for rectal cancer from two medical centers(one discovery cohort and one external validation cohort)were included in this retrospective study.For the discovery cohort,the machine learning prediction algorithms were developed and internally validated.In the external validation cohort,we evaluated the trained model using various performance metrics.Further,the clinical utility of the model was tested by decision curve analysis.RESULTS Overall,1651 patients were included in the present study.Anastomotic height,neoadjuvant therapy,diverting stoma,body mass index,clinical stage,specimen length,tumor size,and age were the risk factors associated with major LARS.They were used to construct the machine learning model to predict major LARS.The trained random forest(RF)model performed with an area under the curve of 0.852 and a sensitivity of 0.795(95%CI:0.681-0.877),a specificity of 0.758(95%CI:0.671-0.828),and Brier score of 0.166 in the external validation set.Compared to the previous preoperative LARS score model,the current model exhibited superior predictive performance in predicting major LARS in our cohort(accuracy of 0.772 for the RF model vs 0.355 for the preoperative LARS score model).CONCLUSION We developed and validated a robust tool for predicting major LARS.This model could potentially be used in the clinic to identify patients with a high risk of developing major LARS and then improve the quality of life.
文摘The Cr-plated coating inside a gun barrel can effectively improve the barrel’s erosion resistance and thus increase the service life.However,due to the cyclic thermal load caused by high-temperature gunpowder,micro-element damage tends to occur within the Cr coating/steel substrate interface,leading to a gradual deterioration in macro-mechanical properties for the material in the related region.In order to mimic this cyclic thermal load and,thereby,study the thermal erosion behavior of the Cr coating on the barrel’s inner wall,a laser emitter is utilized in the current study.With the help of in-situ tensile test and finite element simulation results,a shear stress distribution law of the Cr coating/steel substrate and a change law of the interface ultimate shear strength are identified.Studies have shown that the Cr coating/steel substrate interface’s ultimate shear strength has a significant weakening effect due to increasing temperature.In this study,the interfacial ultimate shear strength decreases from 2.57 GPa(no erosion)to 1.02 GPa(laser power is 160 W).The data from this experiment is employed to establish a Cr coating/steel substrate interface shear damage model.And this model is used to predict the flaking process of Cr coating by finite element method.The simulation results show that the increase of coating crack spacing and coating thickness will increase the service life of gun barrel.
基金financially supported by Beijing Key Laboratory for Corrosion-Erosion and Surface Technology,Beijing Municipal Education Commission Project(SYS100080419)。
文摘An increase in the use of the gun barrel will cause wear of the inner wall,which reduces the muzzle velocity and the spin rate of the projectile.The off-bore flight attitude and trajectory of the projectile also change,affecting the shooting power and the accuracy.Exterior ballistic data of a high-speed spinning projectile are required to study the performance change.Therefore,based on the barrel’s accelerated life test,the whole process of projectile shooting is reproduced using numerical simulation technology,and key information on the ballistic performance change at each shooting stage are acquired.Studies have shown that in the later stages of barrel shooting,the accuracy of shooting has not decreased significantly.However,it is found that the angle of attack of the projectile increases as the wear of the barrel increases.The maximum angle of attack reaches 0.106 rad when the number of shots reaches 4300.Meanwhile,elliptical bullet hole has appeared on the target at this shooting stage.Through combining external ballistic theory with simulation results,the primary reason of this phenomenon is found to be a significant decrease in the muzzle spin rate of the projectile.At the end of the barrel life,the projectile muzzle spin rate is 57.5%lower than that of a barrel without wear.
基金Financial support from the National Natural Science Foundation of China(Nos.21172121,21475065)the Fundamental Research Funds for the Central Universities
文摘Combining with electrospray ionization(ESI)mass spectrometry,infrared photodissociation(IRPD)spectroscopy is a powerful method to study structures of cluster ions in the gas phase.In this paper,infrared photodissociation spectrum of Pro_4H~+in the range of 2700–3600 cm 1was obtained experimentally.Both theoretically predicted spectra of the two most stable isomers of Pro4^(-1)and Pro4^(-2)obtained at the level of M062X/6-31+G(d,p)are in good consistent with the experimental results.The two isomers have similar structures and close energies.Both of them only consist of zwitterionic units,indicating the strong salt-bridged interactions inside the clusters.And the calculated collision cross section(ccs)of Pro4-1 is found to be very close to the experimental result previously reported.
文摘We know that the Box dimension of f（x） ∈ C^1[0,1] is 1. In this paper, we prove that the Box dimension of continuous functions with bounded variation is still 1. Furthermore, Box dimension of Weyl fractional integral of above function is also 1.
基金supported by the National Key R&D Project of China(No.2022YFE03030000)National Natural Science Foundation of China(Nos.11975269,12275306 and 12075279)+3 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2022452)the Anhui Provincial Natural Science Foundation(No.2208085J40)the CASHIPS Director’s Fund(Nos.YZJJQY202302 and BJPY2023B03)the Comprehensive Research Facility for Fusion Technology Program of China(No.2018-000052-73-01-001228).
文摘First mirror(FM)cleaning,using radio frequency(RF)plasma,has been proposed to recover FM reflectivity in nuclear fusion reactors such as the International Thermonuclear Experimental Reactor(ITER).To investigate the influence of simultaneous cleaning of two mirrors on mirror cleaning efficiency and uniformity,experiments involving single-mirror cleaning and dual-mirror cleaning were conducted using RF capacitively coupled plasma in the laboratory.For the test and simultaneous cleaning of two mirrors,the FM and second mirror(SM),both measuring 110 mm×80 mm,were placed inside the first mirror unit(FMU).They were composed of 16 mirror samples,each with a dimension of 27.5 mm×20 mm.These mirror samples consist of a titanium-zirconium-molybdenum alloy substrate,a 500 nm Mo intermediate layer and a 30 nm Al_(2)O_(3) surface coating as a proxy for Be impurities.The cleaning of a single first mirror(SFM)and the simultaneous cleaning of the FM and SM(DFM and DSM)lasted for 9 h using Ar plasma at a pressure of 1 Pa.The total reflectivity of mirror samples on the DSM did not fully recover and varied with location,with a self-bias of−140 V.With a self-bias of−300 V,the total reflectivity of mirror samples on the SFM and DFM was fully recovered.The energy dispersive spectrometer results demonstrated that the Al_(2)O_(3) coating had been completely removed from these mirror samples.However,the mass loss of each mirror sample on the SFM and DFM before and after cleaning varied depending on its location,with higher mass loss observed for mirror samples located in the corners and lower loss for those in the center.Compared with SM cleaning,the simultaneous cleaning of two mirrors reduced the difference between the highest and lowest mass loss.Furthermore,this mass loss for the mirror samples of the DFM facing the DSM was increased.This indicated that mirror samples cleaned face to face in the FMU simultaneously could influence each other,highlighting the need for special attention in future studies.
文摘Skin is one of the most vulnerable tissues,but there is a lack of injectable bioactive hydrogel dressings,which possess high strength,antiswelling capacity,and wet tissue adhesiveness,but also a rapid gelling process to enable rapid hemostasis,sutureless wound closure,and scarless healing of infected skin wounds[1e5].A new injectable,antibacterial,and multifunctional hydrogel dressings based on poly(citric acid-co-polyethylene glycol)-g-dopamine(PCPD)and amino-terminated Pluronic F127(APF)mi-celles loaded with astragaloside IV(AS)was developed for this pur-pose,as shown in Fig.1A[6].
基金National Natural Science Foundation of China(52275515)National Key Research and Development Program of China(2024YFE03000200)Open Funding of Magnetic Confinement Fusion Laboratory of Modern Manufacturing Quality Engineering(K13092055)。
文摘Traditional vortex beam parameter determination methods are all designed for aberration-free vortex beams.In the case of aberrations and turbulence,they tend to struggle in mutual restraint between phase recovery and topological charge(TC)detection.Most recent methods depend on complex interferometric setups and precise phase singularity localization.An iterative virtual Moiréreconstruction(IVMR)technique is proposed based on the blind conformal mapping,achieving simultaneous demodulation of TC and phase from a single-frame aberrated interferogram,not needing precise phase singularity positioning.
基金This study was supported by the grants from the National Natural Science Foundation of China(No.81570383)the Beijing Municipal Science&Technology Commission(No.Z141100002114029)
文摘Background:The association between dietary sodium intake and blood pressure variability(BPV)in hypertensive patients remains unclear.The objective of this study was to demonstrate whether dietary sodium intake is a predictor of elevated BPV in Chinese patients with hypertension.Methods:A total of 235 patients with essential hypertension were enrolled in the Department of Cardiology,Chinese People’s Liberation Army(PLA)General Hospital in 2018 to 2019,all of whom underwent 24-h ambulatory blood pressure monitoring.BPV was calculated as the standard deviation(SD),coefficient of variation(CV),variation independent of mean(VIM)of blood pressure measurements,respectively,and divided into diurnal systolic BPV(SBPV),diurnal diastolic BPV(DBPV),nocturnal SBPV,and nocturnal DBPV.24-h urine samples were collected to measure 24-h urine sodium excretion,which represents dietary sodium intake.The relationship between dietary sodium intake and BPV was analyzed by using Spearman correlations and multiple linear regression analysis.Results:Nocturnal SBPV-SD,CV,VIM,and nocturnal DBPV-SD in the high urine sodium excretion group were significantly higher than those in the medium and low urine sodium excretion groups,whereas diurnal SBPV-SD,CV,VIM,diurnal DBPV-SD,CV,VIM,and nocturnal DBPV-CV,VIM were not.Using the Spearman correlation analysis,we found a linear correlation between 24-h urine sodium excretion and nocturnal SBPV-SD,CV,VIM(SD,r=0.22,P=0.001;CV,r=0.17,P=0.009;VIM,r=0.16,P=0.020),nocturnal DBPV-SD(r=0.21,P=0.001),respectively.After further adjusting for confounding factors by multiple linear regression,the positive correlations remained between 24-h urine sodium excretion and nocturnal SBPV-SD,CV,VIM(SD,β=0.224,P<0.001;CV,β=0.211,P=0.001;VIM,β=0.213,P=0.001),nocturnal DBPV(SD,β=0.215,P=0.001),respectively.Conclusions:Dietary sodium intake is associated with nocturnal SBPV in Chinese patients with hypertension.
基金H.Y.is grateful to the financial support from the National Key Research and Development Program of China(Grant Nos.2022YFA1404700 and 2021YFA1400100)the National Natural Science Foundation of China(Grant No.12074085)+7 种基金the Natural Science Foundation of Shanghai(Grant No.23XD1400200)C.W.is grateful to the financial support from the National Natural Science Foundation of China(Grant Nos.12274030,11704075)the National Key Research and Development Program of China(Grant No.2022YFA1403400)F.S.acknowledges the financial support from the National Key Research and Development Program of China(Grant No.2017YFA0303203)the National Natural Science Foundation of China(Grant Nos.92161201,12025404,11904165,and 12274208)the Natural Science Foundation of Jiangsu Province(Grant No.BK20190286)S.H.is grateful to the financial support from the China Postdoctoral Science Foundation(Grant No.2020TQ0078)Part of the experimental work was carried out in Fudan Nanofabrication Lab.
文摘Naturally existing in-plane hyperbolic polaritons and the associated optical topological transitions,which avoid the nano-structuring to achieve hyperbolicity,can outperform their counterparts in artificial metasurfaces.Such plasmon polaritons are rare,but experimentally revealed recently in WTe_(2)van der Waals thin films.Different from phonon polaritons,hyperbolic plasmon polaritons originate from the interplay of free carrier Drude response and interband transitions,which promise good intrinsic tunability.However,tunable in-plane hyperbolic plasmon polariton and its optical topological transition of the isofrequency contours to the elliptic topology in a natural material have not been realized.Here we demonstrate the tuning of the optical topological transition through Mo doping and temperature.The optical topological transition energy is tuned over a wide range,with frequencies ranging from 429 cm^(−1)(23.3 microns)for pure WTe_(2)to 270 cm^(−1)(37.0 microns)at the 50%Mo-doping level at 10 K.Moreover,the temperature-induced blueshift of the optical topological transition energy is also revealed,enabling active and reversible tuning.Surprisingly,the localized surface plasmon resonance in skew ribbons shows unusual polarization dependence,accurately manifesting its topology,which renders a reliable means to track the topology with far-field techniques.Our results open an avenue for reconfigurable photonic devices capable of plasmon polariton steering,such as canaling,focusing,and routing,and pave the way for low-symmetry plasmonic nanophotonics based on anisotropic natural materials.
基金supported by the Young Innovative Talents in Higher Education of Guangdong(NO.6020210025K).
文摘Nowadays,end fitting corrosion reduces the mechanical strength and flashover voltage of insulators,forming a huge threat to high‐voltage direct current transmission lines.At present,the parameters of electrolytic corrosion inhibition measures are selected based on the premise of the constant annual corrosion rate.However,with the development of corrosion,corrosion products accumulate on the insulator surface,which may impact the corrosion rate.In order to clarify the influence of corrosion products,this work studied how corrosion products influence the corrosion rate from the corrosion phenomenon,corrosion current,feature and formation of corrosion products.The results showed that corrosion products of iron and zinc were excellent in adhesion on the insulator surface and could not be cleaned by rain,which was able to increase the corrosion rate.In future,in the selection of the quality of the zinc ring bonded on insulator fittings,there will be a demand to consider the influence of corrosion products on the corrosion rate.
