The detection of hypersonic targets usually confronts range migration(RM)issue before coherent integration(CI).The traditional methods aiming at correcting RM to obtain CI mainly considers the narrow-band radar condit...The detection of hypersonic targets usually confronts range migration(RM)issue before coherent integration(CI).The traditional methods aiming at correcting RM to obtain CI mainly considers the narrow-band radar condition.However,with the increasing requirement of far-range detection,the time bandwidth product,which is corresponding to radar’s mean power,should be promoted in actual application.Thus,the echo signal generates the scale effect(SE)at large time bandwidth product situation,influencing the intra and inter pulse integration performance.To eliminate SE and correct RM,this paper proposes an effective algorithm,i.e.,scaled location rotation transform(ScLRT).The ScLRT can remove SE to obtain the matching pulse compression(PC)as well as correct RM to complete CI via the location rotation transform,being implemented by seeking the actual rotation angle.Compared to the traditional coherent detection algorithms,Sc LRT can address the SE problem to achieve better detection/estimation capabilities.At last,this paper gives several simulations to assess the viability of ScLRT.展开更多
Dispersion fuels,knowned for their excellent safety performance,are widely used in advanced reactors,such as hightemperature gas-cooled reactors.Compared with deterministic methods,the Monte Carlo method has more adva...Dispersion fuels,knowned for their excellent safety performance,are widely used in advanced reactors,such as hightemperature gas-cooled reactors.Compared with deterministic methods,the Monte Carlo method has more advantages in the geometric modeling of stochastic media.The explicit modeling method has high computational accuracy and high computational cost.The chord length sampling(CLS)method can improve computational efficiency by sampling the chord length during neutron transport using the matrix chord length?s probability density function.This study shows that the excluded-volume effect in realistic stochastic media can introduce certain deviations into the CLS.A chord length correction approach is proposed to obtain the chord length correction factor by developing the Particle code based on equivalent transmission probability.Through numerical analysis against reference solutions from explicit modeling in the RMC code,it was demonstrated that CLS with the proposed correction method provides good accuracy for addressing the excludedvolume effect in realistic infinite stochastic media.展开更多
The self-heating effect severely limits device performance and reliability.Although some studies have revealed the heat distribution ofβ-Ga_(2)O_(3) MOSFETs under biases,those devices all have small areas and have di...The self-heating effect severely limits device performance and reliability.Although some studies have revealed the heat distribution ofβ-Ga_(2)O_(3) MOSFETs under biases,those devices all have small areas and have difficulty reflecting practical con-ditions.This work demonstrated a multi-fingerβ-Ga_(2)O_(3) MOSFET with a maximum drain current of 0.5 A.Electrical characteris-tics were measured,and the heat dissipation of the device was investigated through infrared images.The relationship between device temperature and time/bias is analyzed.展开更多
Objective:To explore the corrective effect of posterior chamber intraocular lens implantation with phakic eyes in the treatment of high myopia and astigmatism.Methods:From May 2023,the hospital began to collect the ca...Objective:To explore the corrective effect of posterior chamber intraocular lens implantation with phakic eyes in the treatment of high myopia and astigmatism.Methods:From May 2023,the hospital began to collect the case data of diagnosis and treatment of high myopia and astigmatism.By May 2024,310 cases were included,all of which were treated with posterior chamber intraocular lens implantation.The visual acuity,astigmatism and axial position of the intraocular lens were observed before and after treatment.Results:At different time points after the operation,the patient’s vision was significantly improved compared with that before the operation(P<0.05),and the vision level was equal to or greater than the best-corrected vision before the operation.At different time points after the operation,the average rotation of the intraocular lens was less than 5 degrees.Astigmatism was significantly lower than that before the operation(P<0.05).After the operation,the intraocular pressure increased in 11 cases,accounting for 3.55%,with no adverse complications such as lens turbidity,glare and obvious halo occurring.Conclusion:The posterior chamber intraocular lens implantation with phakic eyes has an ideal correction effect in the treatment of high myopia and astigmatism,which can effectively improve the vision level of patients and reduce the degree of astigmatism,and has high effectiveness and safety.展开更多
Dynamic self-heating effect(SHE)of silicon-on-insulator(SOI)MOSFET is comprehensively evaluated by ultrafast pulsed I-V measurement in this work.It is found for the first time that the SHE complete heating response an...Dynamic self-heating effect(SHE)of silicon-on-insulator(SOI)MOSFET is comprehensively evaluated by ultrafast pulsed I-V measurement in this work.It is found for the first time that the SHE complete heating response and cooling response of SOI MOSFETs are conjugated,with two-stage curves shown.We establish the effective thermal transient response model with stage superposition corresponding to the heating process.The systematic study of SHE dependence on workload shows that frequency and duty cycle have more significant effect on SHE in first-stage heating process than in the second stage.In the first-stage heating process,the peak lattice temperature and current oscillation amplitude decrease by more than 25 K and 4%with frequency increasing to 10 MHz,and when duty cycle is reduced to 25%,the peak lattice temperature drops to 306 K and current oscillation amplitude decreases to 0.77%.Finally,the investigation of two-stage(heating and cooling)process provides a guideline for the unified optimization of dynamic SHE in terms of workload.As the operating frequency is raised to GHz,the peak temperature depends on duty cycle,and self-heating oscillation is completely suppressed.展开更多
Laser-induced breakdown spectroscopy(LIBS)has been used for soil analysis,but its measurement accuracy is often influenced by matrix effects of different kinds of soils.In this work,a method for matrix effect suppress...Laser-induced breakdown spectroscopy(LIBS)has been used for soil analysis,but its measurement accuracy is often influenced by matrix effects of different kinds of soils.In this work,a method for matrix effect suppressing was developed using laser-induced plasma acoustic signals to correct the original spectrum,thereby improving the analysis accuracy of the soil elements.A good linear relationship was investigated firstly between the original spectral intensity and the acoustic signals.The relative standard deviations(RSDs)of Mg,Ca,Sr,and Ba elements were then calculated for both the original spectrum and the spectrum with the acoustic correction,and the RSDs were significantly reduced with the acoustic correction.Finally,calibration curves of MgⅠ285.213 nm,CaⅠ422.673 nm,SrⅠ460.733 nm and BaⅡ455.403 nm were established to assess the analytical performance of the proposed acoustic correction method.The values of the determination coefficient(R~2)of the calibration curves for Mg,Ca,Sr,and Ba elements,corrected by the acoustic amplitude,are improved from 0.9845,0.9588,0.6165,and 0.6490 to 0.9876,0.9677,0.8768,and 0.8209,respectively.The values of R~2 of the calibration curves corrected by the acoustic energy are further improved to 0.9917,0.9827,0.8835,and 0.8694,respectively.These results suggest that the matrix effect of LIBS on soils can be clearly improved by using acoustic correction,and acoustic energy correction works more efficiently than acoustic amplitude correction.This work provides a simple and efficient method for correcting matrix effects in the element analysis of soils by acoustic signals.展开更多
The efficacy of error correction and various kinds of correction approaches is one of the key issues in second language writing faced by both teachers and researchers. The current paper reviews the definition of error...The efficacy of error correction and various kinds of correction approaches is one of the key issues in second language writing faced by both teachers and researchers. The current paper reviews the definition of error correction and examines the different views on whether error correction in L2 writing should be corrected. In particular, the paper discusses and analyses the three common correction methods: direct correction, peer feedback and indirect correction. Teachers are encouraged to weigh and analyze the advantages and disadvantages of these methods according to the current literature, employ the most beneficial error correction method in L2 writing, and adapt its suitability to their teaching context.展开更多
Anomaly separation using geochemical data often involves operations in the frequency domain, such as filtering and reducing noise/signal ratios. Unfortunately, the abrupt edge truncation of an image along edges and ho...Anomaly separation using geochemical data often involves operations in the frequency domain, such as filtering and reducing noise/signal ratios. Unfortunately, the abrupt edge truncation of an image along edges and holes (with missing data) often causes frequency distribution distortion in the frequency domain. For example, bright strips are commonly seen in frequency distribution when using a Fourier transform. Such edge effect distortion may affect information extraction results; sometimes severely, depending on the edge abruptness of the image. Traditionally, edge effects are reduced by smoothing the image boundary prior to applying a Fourier transform. Zero-padding is one of the most commonly used smoothing methods. This simple method can reduce the edge effect to some degree but still distorts the image in some cases. Moreover, due to the complexity of geoscience images, which can include irregular shapes and holes with missing data, zero-padding does not always give satisfactory results. This paper proposes the use of decay functions to handle edge effects when extracting information from geoscience images. As an application, this method has been used in a newly developed multifractal method (S-A) for separating geochemical anomalies from background patterns. A geochemical dataset chosen from a mineral district in Nova Scotia, Canada was used to validate the method.展开更多
BACKGROUND In children, it is common to see failure and recurrence in the correction ofepiblepharon and to have reoperation due to obvious irritation symptoms andcorneal injury.AIM To explore the causes of failure and...BACKGROUND In children, it is common to see failure and recurrence in the correction ofepiblepharon and to have reoperation due to obvious irritation symptoms andcorneal injury.AIM To explore the causes of failure and recurrence after epiblepharon correction inchildren, to remove accurately redundant epiblepharon and orbicularis oculimuscle in patients via the cilia-everting suture technique combined with lidmargin splitting in some patients due to inverted lashes in the medial part of theeyelid, and to observe the therapeutic effect.METHODS From 2015 to 2019, in the Outpatient Department of Ophthalmology of BeijingTongren Hospital, 22 children (40 eyes) with epiblepharon, aged 5-12 years, weretreated due to correction failure and recurrence. Fourteen patients (28 eyes)underwent the full-thickness everting suture technique, and eight patients (16eyes) underwent incisional surgery. They were treated by reviewing the previoussurgical methods and observing epiblepharon, eyelash direction, and cornealinjury. During reoperation, a subciliary incision was made 1 mm below theinferior lash line. Incisional surgery for the lower eyelid was used to removeaccurately redundant epiblepharon and part of the pretarsal orbicularis muscle.Subcutaneous tissue and the orbicularis muscle of the upper skin-muscle flapwere anchored to the anterior fascia of the tarsal plate by rotational sutures. Lidmargin splitting was used only for patients who had seriously inverted lasheslocated in the medial part of the eyelid. All patients were followed for 6-12 moafter reoperation to observe the lower eyelid position, skin incision, eyelash direction, corneal damage, and recurrence.RESULTS After reoperation, all the patients were corrected. Photophobia, rubbing the eye,winking, and tearing disappeared. There was no lower eyelid entropion,ectropion, or retraction. There was no obvious sunken scar or lower eyelid crease.The eyelashes were far away from the cornea, and when the patients lookeddown, the eyelashes on the lower eyelid did not contact the cornea or conjunctiva.The corneal injuries were repaired. Follow-up observation for 6 mo showed norecurrence of epiblepharon.CONCLUSION The type of suture method, the failure to remove accurately redundant skin andorbicularis muscle, the lack of cilia rotational suture use, and excessive reversegrowth of eyelashes are the main causes of failure and recurrence afterepiblepharon correction in children.展开更多
High resolution Fresnel zone plates for nanoscale three-dimensional imaging of materials by both soft and hard x-rays are increasingly needed by the broad applications in nanoscience and nanotechnology.When the outmos...High resolution Fresnel zone plates for nanoscale three-dimensional imaging of materials by both soft and hard x-rays are increasingly needed by the broad applications in nanoscience and nanotechnology.When the outmost zone-width is shrinking down to 50 nm or even below,patterning the zone plates with high aspect ratio by electron beam lithography still remains a challenge because of the proximity effect.The uneven charge distribution in the exposed resist is still frequently observed even after standard proximity effect correction(PEC),because of the large variety in the line width.This work develops a new strategy,nicknamed as local proximity effect correction(LPEC),efficiently modifying the deposited energy over the whole zone plate on the top of proximity effect correction.By this way,50 nm zone plates with the aspect ratio from 4:1 up to 15:1 and the duty cycle close to 0.5 have been fabricated.Their imaging capability in soft(1.3 keV)and hard(9 keV)x-ray,respectively,has been demonstrated in Shanghai Synchrotron Radiation Facility(SSRF)with the resolution of 50 nm.The local proximity effect correction developed in this work should also be generally significant for the generation of zone plates with high resolutions beyond 50 nm.展开更多
Objective:To observe whether the Ear Well infant ear correction system makes any difference in terms of the treatment effect,duration,complication rate,and nursing care requirements in different types of infant auricl...Objective:To observe whether the Ear Well infant ear correction system makes any difference in terms of the treatment effect,duration,complication rate,and nursing care requirements in different types of infant auricle deformities.Methods:A total of 93 infant patients with auricular deformity(age:<3 months of age)who were diagnosed and treated in Guangzhou Children and Women’s Medical Center from April 2018 to September 2020 were selected and treated with the Ear Well infant ear correction system.We observed and recorded the effects of the Ear Well infant ear correction system,the treatment duration,the number of rebound cases,and complications that are likely to occur during treatment,and noted the related factors causing complications and the relative requirements for nursing care.Results:The Earwell infant ear correction system could effectively correct infant auricle deformities.Among the 93 cases,90 cases had positive therapeutical outcome and the effective rate was 96.77%.The treatment duration for lop ear and protruding ear was longer than for other auricle deformities;the deformity recoil and the treatment compilation rates were much higher for these 2 deformity types,and the difference was statistically significant(P<0.05).Conclusions:The treatment suggestion for the wearing duration of the Ear Well infant ear correction system for lop ear and protruding ear is a prolonged duration compared with that for other infant auricle deformities.Fur ther,the requirements for nursing care intensity and infant patient’s guardian’s nursing knowledge and skill are obviously increased for these 2 types of auricle deformities.展开更多
Matrix effect primarily impacts the accuracy and precision of zircon LA-ICP-MS U-Pb data.This paper describes three types of matrix effect in zircon LA-ICPMS U-Pb dating,i.e.,the element matrix effect,high Ddpa or ura...Matrix effect primarily impacts the accuracy and precision of zircon LA-ICP-MS U-Pb data.This paper describes three types of matrix effect in zircon LA-ICPMS U-Pb dating,i.e.,the element matrix effect,high Ddpa or uranium matrix effect and alpha dose matrix effect,and illustrates the correction of these three effects.In addition,we point out the limitation and possible problems of the existing correction methods.展开更多
This paper points out that with interference from their native language and culture, Chinese students will inevitably make some errors in the process of learning English. It is important for teachers to know when and ...This paper points out that with interference from their native language and culture, Chinese students will inevitably make some errors in the process of learning English. It is important for teachers to know when and how to correct the students’ errors. By employing error-correction skillfully and appropriately, one can expect to improve the present English teaching and learning, to develop the self-confidence and self-esteem in students themselves.展开更多
In the original publication the resolution of Figures 1 and 2 need improvement.The correct version of figures is available in this correction.The original article has been corrected.
A new self-heating effect model for 4H-SiC MESFETs is proposed based on a combination of an analytical and a computer aided design （CAD） oriented drain current model. The circuit oriented expressions of 4H-SiC low-f...A new self-heating effect model for 4H-SiC MESFETs is proposed based on a combination of an analytical and a computer aided design （CAD） oriented drain current model. The circuit oriented expressions of 4H-SiC low-field electron mobility and incomplete ionization rate, which are related to temperature, are presented in this model, which are used to estimate the self-heating effect of 4H-SiC MESFETs. The verification of the present model is made, and the good agreement between simulated results and measured data of DC I - V curves with the self-heating effect is obtained.展开更多
We calculate the energy levels of He+ ion placed in a uniform magnetic field directed perpendicular to the direction of its center of mass (CM) velocity vector, correct to relative order . Our calculations are within ...We calculate the energy levels of He+ ion placed in a uniform magnetic field directed perpendicular to the direction of its center of mass (CM) velocity vector, correct to relative order . Our calculations are within the frame work of an approximately relativistic theory, correct to relative order , of a two-particle composite system bound by electromagnetic forces, and written in terms of the position, momentum and spin operators of the constituent particles as proposed by Krajcik and Foldy, and also by Close and Osborn. Since the He+ ion has a net electric charge, the total or the CM momentum is not conserved and a neat separation of the CM and the internal motion is not possible. What is new in our approach is that, for the basis states in a first order degenerate perturbation theory to calculate the effects of the external magnetic field, we use the direct product of the coherent state of the Landau Hamiltonian of the He+ ion in a uniform magnetic field and of the simultaneous eigenstate of the internal Hamiltonian h, j2, l2, s2 and jz,?where j, l and s are the internal total, orbital and spin angular moments of the He+ ion. The coherent state is an excellent approximation to the expected classical circular motion of the center of mass (CM) of the He+ ion. In addition to the Z2 a2 corrections to the usual nonrelativistic results, including the small corrections due to the nuclear motion, we also obtain corrections which depend on the kinetic energy (ECM ) of the CM circular motion of the He+ ion, in a nontrivial way. Even though these corrections are proportional to , where M is the mass of the He+ ion, and are small for nonrelativistic CM motion, the results should be verifiable in careful experiments. Our results may also have application in astrophysical observations of the spectral lines of He+ ions in magnetized astrophysical objects.展开更多
Considering the gravitational correction through introduction of weakly interacting light vector U bosons, not only the equation of state （EoS） of the neutron star matter, but also the cooling properties of neutron ...Considering the gravitational correction through introduction of weakly interacting light vector U bosons, not only the equation of state （EoS） of the neutron star matter, but also the cooling properties of neutron stars may be changed. In this work, effects of gravitational correction on neutrino emission and cooling of neutron stars in the matter with neutrons, protons, electrons, muons, △- and △0 are studied by the relativistic mean field theory and the related cooling theory. The results show that the effects are sensitive to the ratio of coupling strength to mass squared of U bosons, defined as gu. With increasing gu, the radial region where direct Urca process of nucleons can be allowed in a neutron star with the fixed mass becomes narrower, while the neutrino emissivity is somewhat higher. Moreover, the gravitational correction suppresses the effects of △- on neutrino emission. The gravitational correction leads the star to cool faster, and the higher the gu is, the faster the star cools.展开更多
Rain is one of the main sources of error in dual-frequency altimeter Jason-1 wind measurement. In this study, a new radar altimeter backscatter model is proposed and validated to eliminate rain effects. The model take...Rain is one of the main sources of error in dual-frequency altimeter Jason-1 wind measurement. In this study, a new radar altimeter backscatter model is proposed and validated to eliminate rain effects. The model takes into account attenuation, volume backscattering, and sea surface perturbation by raindrops under rain conditions. A match-up dataset is built to evaluate rain effects, in combination with the Jason-1 normalized radar cross section, precipitation radar data from the Tropical Rainfall Measuring Mission, and sea surface wind reanalysis data from the European Centre for Medium-Range Weather Forecasts. The results show that rain-induced surface perturbation backscatter increases with rain rate at Ku-band, but their correlation at C-band is poor. In addition, rain surface perturbation and attenuation have major effects on radar altimeter wind measurements. Finally, a rain correction model for Jason-1 winds is developed and validation results prove its ability to reduce rain-induced inaccuracies in wind retrievals.展开更多
Self-heating effect in amorphous InGaZnO thin-film transistors remains a critical issue that degrades device performance and stability, hindering their wider applications. In this work, pulsed current–voltage analysi...Self-heating effect in amorphous InGaZnO thin-film transistors remains a critical issue that degrades device performance and stability, hindering their wider applications. In this work, pulsed current–voltage analysis has been applied to explore the physics origin of self-heating induced degradation, where Joule heat is shortly accumulated by drain current and dissipated in repeated time cycles as a function of gate bias. Enhanced positive threshold voltage shift is observed at reduced heat dissipation time, higher drain current, and increased gate width. A physical picture of Joule heating assisted charge trapping process has been proposed and then verified with pulsed negative gate bias stressing scheme, which could evidently counteract the self-heating effect through the electric-field assisted detrapping process. As a result, this pulsed gate bias scheme with negative quiescent voltage could be used as a possible way to actively suppress self-heating related device degradation.展开更多
We discuss a new class of RSII braneworld cosmology exhibiting accelerated expansion and dominated by quintessence. It is explicitly demonstrated that the universe expansion history （transition from inflation to dece...We discuss a new class of RSII braneworld cosmology exhibiting accelerated expansion and dominated by quintessence. It is explicitly demonstrated that the universe expansion history （transition from inflation to deceleration epoch to acceleration and effective quintessence era） may naturally occur in such unified theory for some classes of inverse scalar potentials. Besides a decaying effective cosmological constant, the model incorporates an increasing black hole mass, an increasing Maxwellian electrical charge with cosmic time and a time-dependent brahe tension. The cosmological model exhibits several features of cosmological and astrophysical interest for both the early and late universe consistent with recent observations, in particular the ones concerned with the gravitational constants, black holes masses and charges and variation of the gauge coupling parameters with cosmic time. One interesting mark of the constructed model concerns the fact that a black hole mass surrounded by quintessence energy may increase with time even if the horizon disappears.展开更多
基金supported by the National Natural Science Foundation of China(62101099)the Chinese Postdoctoral Science Foundation(2021M690558,2022T150100,2018M633352,2019T120825)+3 种基金the Young Elite Scientist Sponsorship Program(YESS20200082)the Aeronautical Science Foundation of China(2022Z017080001)the Open Foundation of Science and Technology on Electronic Information Control Laboratorythe Natural Science Foundation of Sichuan Province(2023NSFSC1386)。
文摘The detection of hypersonic targets usually confronts range migration(RM)issue before coherent integration(CI).The traditional methods aiming at correcting RM to obtain CI mainly considers the narrow-band radar condition.However,with the increasing requirement of far-range detection,the time bandwidth product,which is corresponding to radar’s mean power,should be promoted in actual application.Thus,the echo signal generates the scale effect(SE)at large time bandwidth product situation,influencing the intra and inter pulse integration performance.To eliminate SE and correct RM,this paper proposes an effective algorithm,i.e.,scaled location rotation transform(ScLRT).The ScLRT can remove SE to obtain the matching pulse compression(PC)as well as correct RM to complete CI via the location rotation transform,being implemented by seeking the actual rotation angle.Compared to the traditional coherent detection algorithms,Sc LRT can address the SE problem to achieve better detection/estimation capabilities.At last,this paper gives several simulations to assess the viability of ScLRT.
文摘Dispersion fuels,knowned for their excellent safety performance,are widely used in advanced reactors,such as hightemperature gas-cooled reactors.Compared with deterministic methods,the Monte Carlo method has more advantages in the geometric modeling of stochastic media.The explicit modeling method has high computational accuracy and high computational cost.The chord length sampling(CLS)method can improve computational efficiency by sampling the chord length during neutron transport using the matrix chord length?s probability density function.This study shows that the excluded-volume effect in realistic stochastic media can introduce certain deviations into the CLS.A chord length correction approach is proposed to obtain the chord length correction factor by developing the Particle code based on equivalent transmission probability.Through numerical analysis against reference solutions from explicit modeling in the RMC code,it was demonstrated that CLS with the proposed correction method provides good accuracy for addressing the excludedvolume effect in realistic infinite stochastic media.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.61925110,62004184 and 62234007the Key-Area Research and Development Program of Guangdong Province under Grant No.2020B010174002.
文摘The self-heating effect severely limits device performance and reliability.Although some studies have revealed the heat distribution ofβ-Ga_(2)O_(3) MOSFETs under biases,those devices all have small areas and have difficulty reflecting practical con-ditions.This work demonstrated a multi-fingerβ-Ga_(2)O_(3) MOSFET with a maximum drain current of 0.5 A.Electrical characteris-tics were measured,and the heat dissipation of the device was investigated through infrared images.The relationship between device temperature and time/bias is analyzed.
文摘Objective:To explore the corrective effect of posterior chamber intraocular lens implantation with phakic eyes in the treatment of high myopia and astigmatism.Methods:From May 2023,the hospital began to collect the case data of diagnosis and treatment of high myopia and astigmatism.By May 2024,310 cases were included,all of which were treated with posterior chamber intraocular lens implantation.The visual acuity,astigmatism and axial position of the intraocular lens were observed before and after treatment.Results:At different time points after the operation,the patient’s vision was significantly improved compared with that before the operation(P<0.05),and the vision level was equal to or greater than the best-corrected vision before the operation.At different time points after the operation,the average rotation of the intraocular lens was less than 5 degrees.Astigmatism was significantly lower than that before the operation(P<0.05).After the operation,the intraocular pressure increased in 11 cases,accounting for 3.55%,with no adverse complications such as lens turbidity,glare and obvious halo occurring.Conclusion:The posterior chamber intraocular lens implantation with phakic eyes has an ideal correction effect in the treatment of high myopia and astigmatism,which can effectively improve the vision level of patients and reduce the degree of astigmatism,and has high effectiveness and safety.
文摘Dynamic self-heating effect(SHE)of silicon-on-insulator(SOI)MOSFET is comprehensively evaluated by ultrafast pulsed I-V measurement in this work.It is found for the first time that the SHE complete heating response and cooling response of SOI MOSFETs are conjugated,with two-stage curves shown.We establish the effective thermal transient response model with stage superposition corresponding to the heating process.The systematic study of SHE dependence on workload shows that frequency and duty cycle have more significant effect on SHE in first-stage heating process than in the second stage.In the first-stage heating process,the peak lattice temperature and current oscillation amplitude decrease by more than 25 K and 4%with frequency increasing to 10 MHz,and when duty cycle is reduced to 25%,the peak lattice temperature drops to 306 K and current oscillation amplitude decreases to 0.77%.Finally,the investigation of two-stage(heating and cooling)process provides a guideline for the unified optimization of dynamic SHE in terms of workload.As the operating frequency is raised to GHz,the peak temperature depends on duty cycle,and self-heating oscillation is completely suppressed.
基金financially supported by National Natural Science Foundation of China(No.12064029)by Jiangxi Provincial Natural Science Foundation(No.20202BABL202024)by the Open project program of Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province(No.ED202208094)。
文摘Laser-induced breakdown spectroscopy(LIBS)has been used for soil analysis,but its measurement accuracy is often influenced by matrix effects of different kinds of soils.In this work,a method for matrix effect suppressing was developed using laser-induced plasma acoustic signals to correct the original spectrum,thereby improving the analysis accuracy of the soil elements.A good linear relationship was investigated firstly between the original spectral intensity and the acoustic signals.The relative standard deviations(RSDs)of Mg,Ca,Sr,and Ba elements were then calculated for both the original spectrum and the spectrum with the acoustic correction,and the RSDs were significantly reduced with the acoustic correction.Finally,calibration curves of MgⅠ285.213 nm,CaⅠ422.673 nm,SrⅠ460.733 nm and BaⅡ455.403 nm were established to assess the analytical performance of the proposed acoustic correction method.The values of the determination coefficient(R~2)of the calibration curves for Mg,Ca,Sr,and Ba elements,corrected by the acoustic amplitude,are improved from 0.9845,0.9588,0.6165,and 0.6490 to 0.9876,0.9677,0.8768,and 0.8209,respectively.The values of R~2 of the calibration curves corrected by the acoustic energy are further improved to 0.9917,0.9827,0.8835,and 0.8694,respectively.These results suggest that the matrix effect of LIBS on soils can be clearly improved by using acoustic correction,and acoustic energy correction works more efficiently than acoustic amplitude correction.This work provides a simple and efficient method for correcting matrix effects in the element analysis of soils by acoustic signals.
文摘The efficacy of error correction and various kinds of correction approaches is one of the key issues in second language writing faced by both teachers and researchers. The current paper reviews the definition of error correction and examines the different views on whether error correction in L2 writing should be corrected. In particular, the paper discusses and analyses the three common correction methods: direct correction, peer feedback and indirect correction. Teachers are encouraged to weigh and analyze the advantages and disadvantages of these methods according to the current literature, employ the most beneficial error correction method in L2 writing, and adapt its suitability to their teaching context.
文摘Anomaly separation using geochemical data often involves operations in the frequency domain, such as filtering and reducing noise/signal ratios. Unfortunately, the abrupt edge truncation of an image along edges and holes (with missing data) often causes frequency distribution distortion in the frequency domain. For example, bright strips are commonly seen in frequency distribution when using a Fourier transform. Such edge effect distortion may affect information extraction results; sometimes severely, depending on the edge abruptness of the image. Traditionally, edge effects are reduced by smoothing the image boundary prior to applying a Fourier transform. Zero-padding is one of the most commonly used smoothing methods. This simple method can reduce the edge effect to some degree but still distorts the image in some cases. Moreover, due to the complexity of geoscience images, which can include irregular shapes and holes with missing data, zero-padding does not always give satisfactory results. This paper proposes the use of decay functions to handle edge effects when extracting information from geoscience images. As an application, this method has been used in a newly developed multifractal method (S-A) for separating geochemical anomalies from background patterns. A geochemical dataset chosen from a mineral district in Nova Scotia, Canada was used to validate the method.
文摘BACKGROUND In children, it is common to see failure and recurrence in the correction ofepiblepharon and to have reoperation due to obvious irritation symptoms andcorneal injury.AIM To explore the causes of failure and recurrence after epiblepharon correction inchildren, to remove accurately redundant epiblepharon and orbicularis oculimuscle in patients via the cilia-everting suture technique combined with lidmargin splitting in some patients due to inverted lashes in the medial part of theeyelid, and to observe the therapeutic effect.METHODS From 2015 to 2019, in the Outpatient Department of Ophthalmology of BeijingTongren Hospital, 22 children (40 eyes) with epiblepharon, aged 5-12 years, weretreated due to correction failure and recurrence. Fourteen patients (28 eyes)underwent the full-thickness everting suture technique, and eight patients (16eyes) underwent incisional surgery. They were treated by reviewing the previoussurgical methods and observing epiblepharon, eyelash direction, and cornealinjury. During reoperation, a subciliary incision was made 1 mm below theinferior lash line. Incisional surgery for the lower eyelid was used to removeaccurately redundant epiblepharon and part of the pretarsal orbicularis muscle.Subcutaneous tissue and the orbicularis muscle of the upper skin-muscle flapwere anchored to the anterior fascia of the tarsal plate by rotational sutures. Lidmargin splitting was used only for patients who had seriously inverted lasheslocated in the medial part of the eyelid. All patients were followed for 6-12 moafter reoperation to observe the lower eyelid position, skin incision, eyelash direction, corneal damage, and recurrence.RESULTS After reoperation, all the patients were corrected. Photophobia, rubbing the eye,winking, and tearing disappeared. There was no lower eyelid entropion,ectropion, or retraction. There was no obvious sunken scar or lower eyelid crease.The eyelashes were far away from the cornea, and when the patients lookeddown, the eyelashes on the lower eyelid did not contact the cornea or conjunctiva.The corneal injuries were repaired. Follow-up observation for 6 mo showed norecurrence of epiblepharon.CONCLUSION The type of suture method, the failure to remove accurately redundant skin andorbicularis muscle, the lack of cilia rotational suture use, and excessive reversegrowth of eyelashes are the main causes of failure and recurrence afterepiblepharon correction in children.
基金Project supported by the National Natural Science Foundation of China(Grant No.U1732104)China Postdoctoral Science Foundation(Grant No.2017M611443)Shanghai STCSM2019-11-20 Grant,China(Grant No.19142202700)。
文摘High resolution Fresnel zone plates for nanoscale three-dimensional imaging of materials by both soft and hard x-rays are increasingly needed by the broad applications in nanoscience and nanotechnology.When the outmost zone-width is shrinking down to 50 nm or even below,patterning the zone plates with high aspect ratio by electron beam lithography still remains a challenge because of the proximity effect.The uneven charge distribution in the exposed resist is still frequently observed even after standard proximity effect correction(PEC),because of the large variety in the line width.This work develops a new strategy,nicknamed as local proximity effect correction(LPEC),efficiently modifying the deposited energy over the whole zone plate on the top of proximity effect correction.By this way,50 nm zone plates with the aspect ratio from 4:1 up to 15:1 and the duty cycle close to 0.5 have been fabricated.Their imaging capability in soft(1.3 keV)and hard(9 keV)x-ray,respectively,has been demonstrated in Shanghai Synchrotron Radiation Facility(SSRF)with the resolution of 50 nm.The local proximity effect correction developed in this work should also be generally significant for the generation of zone plates with high resolutions beyond 50 nm.
文摘Objective:To observe whether the Ear Well infant ear correction system makes any difference in terms of the treatment effect,duration,complication rate,and nursing care requirements in different types of infant auricle deformities.Methods:A total of 93 infant patients with auricular deformity(age:<3 months of age)who were diagnosed and treated in Guangzhou Children and Women’s Medical Center from April 2018 to September 2020 were selected and treated with the Ear Well infant ear correction system.We observed and recorded the effects of the Ear Well infant ear correction system,the treatment duration,the number of rebound cases,and complications that are likely to occur during treatment,and noted the related factors causing complications and the relative requirements for nursing care.Results:The Earwell infant ear correction system could effectively correct infant auricle deformities.Among the 93 cases,90 cases had positive therapeutical outcome and the effective rate was 96.77%.The treatment duration for lop ear and protruding ear was longer than for other auricle deformities;the deformity recoil and the treatment compilation rates were much higher for these 2 deformity types,and the difference was statistically significant(P<0.05).Conclusions:The treatment suggestion for the wearing duration of the Ear Well infant ear correction system for lop ear and protruding ear is a prolonged duration compared with that for other infant auricle deformities.Fur ther,the requirements for nursing care intensity and infant patient’s guardian’s nursing knowledge and skill are obviously increased for these 2 types of auricle deformities.
文摘Matrix effect primarily impacts the accuracy and precision of zircon LA-ICP-MS U-Pb data.This paper describes three types of matrix effect in zircon LA-ICPMS U-Pb dating,i.e.,the element matrix effect,high Ddpa or uranium matrix effect and alpha dose matrix effect,and illustrates the correction of these three effects.In addition,we point out the limitation and possible problems of the existing correction methods.
文摘This paper points out that with interference from their native language and culture, Chinese students will inevitably make some errors in the process of learning English. It is important for teachers to know when and how to correct the students’ errors. By employing error-correction skillfully and appropriately, one can expect to improve the present English teaching and learning, to develop the self-confidence and self-esteem in students themselves.
文摘In the original publication the resolution of Figures 1 and 2 need improvement.The correct version of figures is available in this correction.The original article has been corrected.
基金Project supported by the National Defense Foundation of China (Grant No 51327010101)the National Natural Science Foundation of China (Grant No 60606022)
文摘A new self-heating effect model for 4H-SiC MESFETs is proposed based on a combination of an analytical and a computer aided design （CAD） oriented drain current model. The circuit oriented expressions of 4H-SiC low-field electron mobility and incomplete ionization rate, which are related to temperature, are presented in this model, which are used to estimate the self-heating effect of 4H-SiC MESFETs. The verification of the present model is made, and the good agreement between simulated results and measured data of DC I - V curves with the self-heating effect is obtained.
文摘We calculate the energy levels of He+ ion placed in a uniform magnetic field directed perpendicular to the direction of its center of mass (CM) velocity vector, correct to relative order . Our calculations are within the frame work of an approximately relativistic theory, correct to relative order , of a two-particle composite system bound by electromagnetic forces, and written in terms of the position, momentum and spin operators of the constituent particles as proposed by Krajcik and Foldy, and also by Close and Osborn. Since the He+ ion has a net electric charge, the total or the CM momentum is not conserved and a neat separation of the CM and the internal motion is not possible. What is new in our approach is that, for the basis states in a first order degenerate perturbation theory to calculate the effects of the external magnetic field, we use the direct product of the coherent state of the Landau Hamiltonian of the He+ ion in a uniform magnetic field and of the simultaneous eigenstate of the internal Hamiltonian h, j2, l2, s2 and jz,?where j, l and s are the internal total, orbital and spin angular moments of the He+ ion. The coherent state is an excellent approximation to the expected classical circular motion of the center of mass (CM) of the He+ ion. In addition to the Z2 a2 corrections to the usual nonrelativistic results, including the small corrections due to the nuclear motion, we also obtain corrections which depend on the kinetic energy (ECM ) of the CM circular motion of the He+ ion, in a nontrivial way. Even though these corrections are proportional to , where M is the mass of the He+ ion, and are small for nonrelativistic CM motion, the results should be verifiable in careful experiments. Our results may also have application in astrophysical observations of the spectral lines of He+ ions in magnetized astrophysical objects.
文摘Considering the gravitational correction through introduction of weakly interacting light vector U bosons, not only the equation of state （EoS） of the neutron star matter, but also the cooling properties of neutron stars may be changed. In this work, effects of gravitational correction on neutrino emission and cooling of neutron stars in the matter with neutrons, protons, electrons, muons, △- and △0 are studied by the relativistic mean field theory and the related cooling theory. The results show that the effects are sensitive to the ratio of coupling strength to mass squared of U bosons, defined as gu. With increasing gu, the radial region where direct Urca process of nucleons can be allowed in a neutron star with the fixed mass becomes narrower, while the neutrino emissivity is somewhat higher. Moreover, the gravitational correction suppresses the effects of △- on neutrino emission. The gravitational correction leads the star to cool faster, and the higher the gu is, the faster the star cools.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No.Y0S04300KB)the Major Program for the Research Equipment of Chinese Academy of Sciences (No.YZ200946)
文摘Rain is one of the main sources of error in dual-frequency altimeter Jason-1 wind measurement. In this study, a new radar altimeter backscatter model is proposed and validated to eliminate rain effects. The model takes into account attenuation, volume backscattering, and sea surface perturbation by raindrops under rain conditions. A match-up dataset is built to evaluate rain effects, in combination with the Jason-1 normalized radar cross section, precipitation radar data from the Tropical Rainfall Measuring Mission, and sea surface wind reanalysis data from the European Centre for Medium-Range Weather Forecasts. The results show that rain-induced surface perturbation backscatter increases with rain rate at Ku-band, but their correlation at C-band is poor. In addition, rain surface perturbation and attenuation have major effects on radar altimeter wind measurements. Finally, a rain correction model for Jason-1 winds is developed and validation results prove its ability to reduce rain-induced inaccuracies in wind retrievals.
基金Project supported by the National Key R&D Program of China(Grant No.2016YFB0400100)the National Natural Science Foundation of China(Grant No.91850112)+3 种基金the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20161401)the Priority Academic Program Development of Jiangsu Higher Education Institutions,Chinathe Science and Technology Project of State Grid Corporation of China(Grant No.SGSDDK00KJJS1600071)the Fundamental Research Funds for the Central Universities,China(Grant No.14380098)
文摘Self-heating effect in amorphous InGaZnO thin-film transistors remains a critical issue that degrades device performance and stability, hindering their wider applications. In this work, pulsed current–voltage analysis has been applied to explore the physics origin of self-heating induced degradation, where Joule heat is shortly accumulated by drain current and dissipated in repeated time cycles as a function of gate bias. Enhanced positive threshold voltage shift is observed at reduced heat dissipation time, higher drain current, and increased gate width. A physical picture of Joule heating assisted charge trapping process has been proposed and then verified with pulsed negative gate bias stressing scheme, which could evidently counteract the self-heating effect through the electric-field assisted detrapping process. As a result, this pulsed gate bias scheme with negative quiescent voltage could be used as a possible way to actively suppress self-heating related device degradation.
文摘We discuss a new class of RSII braneworld cosmology exhibiting accelerated expansion and dominated by quintessence. It is explicitly demonstrated that the universe expansion history （transition from inflation to deceleration epoch to acceleration and effective quintessence era） may naturally occur in such unified theory for some classes of inverse scalar potentials. Besides a decaying effective cosmological constant, the model incorporates an increasing black hole mass, an increasing Maxwellian electrical charge with cosmic time and a time-dependent brahe tension. The cosmological model exhibits several features of cosmological and astrophysical interest for both the early and late universe consistent with recent observations, in particular the ones concerned with the gravitational constants, black holes masses and charges and variation of the gauge coupling parameters with cosmic time. One interesting mark of the constructed model concerns the fact that a black hole mass surrounded by quintessence energy may increase with time even if the horizon disappears.
