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
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
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
For exploiting advantages of electron beam air plasma in some unusual applications, a Monte Carlo （MC） model coupled with heat transfer model is established to simulate the characteristics of electron beam air plasm...For exploiting advantages of electron beam air plasma in some unusual applications, a Monte Carlo （MC） model coupled with heat transfer model is established to simulate the characteristics of electron beam air plasma by considering the self-heating effect. Based on the model, the electron beam induced temperature field and the related plasma properties are investigated. The results indicate that a nonuniform temperature field is formed in the electron beam plasma region and the average temperature is of the order of 600 K. Moreover, much larger volume pear-shaped electron beam plasma is produced in hot state rather than in cold state. The beam ranges can, with beam energies of 75 keV and 80 keV, exceed 1.0 m and 1.2 m in air at pressure of 100 torr, respectively. Finally, a well verified formula is obtained for calculating the range of high energy electron beam in atmosphere.展开更多
A thermal model of 4H-SiC MESFET is developed based on the temperature dependences of material parameters and three-region I - V model. The static current characteristics of 4H-SiC MESFET have been obtained with the c...A thermal model of 4H-SiC MESFET is developed based on the temperature dependences of material parameters and three-region I - V model. The static current characteristics of 4H-SiC MESFET have been obtained with the consideration of the self-heating effect on related parameters including electron mobility, saturation velocity and thermal conductivity. High voltage performances are analysed using equivalent thermal conductivity model. Using the physicalbased simulations, we studied the dependence of self-heating temperature on the thickness and doping of substrate. The obtained results can be used for optimization of the thermal design of the SiC-based high-power field effect transistors.展开更多
An inherent self-heating effect of the silicon-on-insulator (SOI) devices limits their application at high current levels. In this paper a novel solution to reduce the self-heating effect is proposed, based on N+ and ...An inherent self-heating effect of the silicon-on-insulator (SOI) devices limits their application at high current levels. In this paper a novel solution to reduce the self-heating effect is proposed, based on N+ and O+ co-implantation into silicon wafer to form a new buried layer structure. This new structure was simulated using Medici program, and the temperature distribution and output characteristics were compared with those of the conventional SOI counterparts. As expected, a reduction of self-heating effect in the novel SOI device was observed.展开更多
Compared with bulk-silicon technology, silicon-on-insulator (SOI) technology possesses many advan-tages but it is inevitable that the buried silicon dioxide layer also thermally insulates the metal – oxide – silicon...Compared with bulk-silicon technology, silicon-on-insulator (SOI) technology possesses many advan-tages but it is inevitable that the buried silicon dioxide layer also thermally insulates the metal – oxide – silicon field-effect transistors (MOSFETs) from the bulk due to the low thermal conductivity. One of the alternative insulator to replace the buried oxide layer is aluminum nitride (AlN), which has a thermal conductivity that is about 200 times higher than that of SiO2 (320 W·m ? 1·K? 1 versus 1.4 W·m? 1·K? 1). To investigate the self-heating effects of small-size MOSFETs fabricated on silicon-on-aluminum nitride (SOAN) substrate, a two-dimensional numerical analysis is performed by using a device simulator called MEDICI run on a Solaris workstation to simulate the electri-cal characteristics and temperature distribution by comparing with those of bulk and standard SOI MOSFETs. Our study suggests that AlN is a suitable alternative to silicon dioxide as a buried dielectric in SOI and expands the appli-cations of SOI to high temperature conditions.展开更多
We use an electro-thermal coupled Monte Carlo simulation framework to investigate the self-heating effect（SHE） in 14 nm bulk n Fin FETs with ambient temperature（TA） from 220 to 400 K. Based on this method, nonloca...We use an electro-thermal coupled Monte Carlo simulation framework to investigate the self-heating effect（SHE） in 14 nm bulk n Fin FETs with ambient temperature（TA） from 220 to 400 K. Based on this method, nonlocal heat generation can be achieved. Contact thermal resistances of Si/Metal and Si/Si O_2 are selected to ensure that the source and drain heat dissipation paths are the first two heat dissipation paths. The results are listed below：（i） not all input power（Q_（input） turns into heat generation in the device region and some is taken out by the thermal non-equilibrium carriers, owing to the serious non-equilibrium transport;（ii） a higher TA leads to a larger ratio of input power turning into heat generation in the device region at the same operating voltages;（iii） SHE can lead to serious degradation in the carrier transport, which will increase when TA increases;（iv） the current degradation can be 8.9% when Vds = 0.7 V, Vgs = 1 V and TA = 400 K;（v） device thermal resistance（Rth） increases with increasing of TA, which is seriously impacted by the non-equilibrium transport. Hence, the impact of TA should be carefully considered when investigating SHE in nanoscale devices.展开更多
To reduce the self-heating effect of strained Si grown on relaxed SiGe-on-insulator（SGOI） n-type metal-oxide-semiconductor field-effect transistors（nMOSFETs）,this paper proposes a novel device called double step b...To reduce the self-heating effect of strained Si grown on relaxed SiGe-on-insulator（SGOI） n-type metal-oxide-semiconductor field-effect transistors（nMOSFETs）,this paper proposes a novel device called double step buried oxide（BOX） SGOI,investigates its electrical and thermal characteristics,and analyzes the effect of self-heating on its electrical parameters.During the simulation of the device,a low field mobility model for strained Si MOSFETs is established and reduced thermal conductivity resulting from phonon boundary scattering is considered.A comparative study of SGOI nMOSFETs with different BOX thicknesses under channel and different channel strains has been performed.By reducing moderately the BOX thickness under the channel,the channel temperature caused by the self-heating effect can be effectively reduced.Moreover,mobility degradation,off state current and a short-channel effect such as drain induced barrier lowering can be well suppressed.Therefore,SGOI MOSFETs with a thinner BOX under the channel can improve the overall performance and long-term reliability efficiently.展开更多
Considering the self-heating effect, an accurate expression for the global interconnection resistance per unit length in terms of interconnection wire width and spacing is presented. Based on the proposed resistance m...Considering the self-heating effect, an accurate expression for the global interconnection resistance per unit length in terms of interconnection wire width and spacing is presented. Based on the proposed resistance model and according to the trade-off theory, a novel optimization analytical model of delay, power dissipation and bandwidth is derived. The proposed optimal model is verified and compared based on 90 nm, 65 nm and 40 nm CMOS technologies. It can be found that more optimum results can be easily obtained by the proposed model. This optimization model is more accurate and realistic than the conventional optimization models, and can be integrated into the global interconnection design ofnano-scale integrated circuits.展开更多
This paper aims to seek expedited fatigue analysis methods using the infrared self-heating technique.The fatigue analysis of NiTi shape memory alloys is obtained through a hybrid approach:fatigue tests to failure yiel...This paper aims to seek expedited fatigue analysis methods using the infrared self-heating technique.The fatigue analysis of NiTi shape memory alloys is obtained through a hybrid approach:fatigue tests to failure yield relatively shorter fatigue lives,while determining the fatigue limit,normally involving extremely high cycles approaching 107 cycles,is directly achieved via self-heating tests.This methodology significantly reduces testing cycles,costing only a fraction of the several-thousand-cycle tests typically required.The validity of this approach is successfully demonstrated through fatigue testing of 18Ni steel:the entire S–N curve is examined using the traditional fatigue test until a life of up to 10^(7) cycles,and the indicated fatigue limit agrees well with the one directly determined through the self-heating method.Subsequently,this developed approach is applied to the fatigue analysis of shape memory alloys under complex loading,enabling the concurrent estimation of the limits of phase transformation-dominated low-cycle fatigue and high-cycle fatigue in the elastic regime on a single specimen.The results obtained align well with other supporting evidence.展开更多
The flexoelectric effect refers to the electromechanical coupling between electric polarization and mechanical strain gradient.It universally exists in a variety of materials in any space group,such as liquid crystals...The flexoelectric effect refers to the electromechanical coupling between electric polarization and mechanical strain gradient.It universally exists in a variety of materials in any space group,such as liquid crystals,dielectrics,biological materials,and semiconductors.Because of its unique size effect,nanoscale flexoelectricity has shown novel phenomena and promising applications in electronics,optronics,mechatronics,and photovoltaics.In this review,we provide a succinct report on the discovery and development of the flexoelectric effect,focusing on flexoelectric materials and related applications.Finally,we discuss recent flexoelectric research progress and still‐unsolved problems.展开更多
Agricultural intensification has led to an increase in monoculture and the use of chemical pesticides,resulting in a decline in biodiversity and a reduction in ecosystem services,particularly biological pest managemen...Agricultural intensification has led to an increase in monoculture and the use of chemical pesticides,resulting in a decline in biodiversity and a reduction in ecosystem services,particularly biological pest management.However,studies have shown that agroforestry can not only improve land productivity and biodiversity but also regulate some ecosystem services.This study reviews the impacts of physical and biological factors on herbivorous pests,parasites,and predatory natural enemies in fruit-crop agroforestry systems.Fruit-crop agroforestry systems provide high spatial heterogeneity by altering crop layouts,regulating the microclimate and soil quality,and offering food resources and shelter for natural enemies,thus promoting biological pest control.This enhances biological control and makes the agrocomplex system an effective tool for sustainable agriculture.Our research shows that volatile plant substances attract or repel pests and natural enemies based on the characteristics of the insects themselves.When scientifically designed,fruit-crop agroforestry systems provide high spatial heterogeneity and favorable microclimatic conditions,which enhance biological pest control and make the agroforestry system an effective tool for sustainable agriculture.Our research shows that fruit-crop agroforestry systems can provide richer food resources and habitat,enhancing biological pest control and improving pest management.展开更多
Liver cancer is the fourth cause of cancer-related deaths and the primary cause of death in patients with compensated cirrhosis.In recent years,the role of traditional Chinese medicine in the treatment of liver cancer...Liver cancer is the fourth cause of cancer-related deaths and the primary cause of death in patients with compensated cirrhosis.In recent years,the role of traditional Chinese medicine in the treatment of liver cancer has attracted more and more attention and recognition.Luteolin(LUT)and glycyrrhetinic(GA)are natural compounds extracted from Chinese herbal medicine.LUT exhibits various biological activity including anti-inflammatory,antibacterial,antiviral,anti-tumor,and neuroprotective effects.GA significantly inhibits the growth and metastasis of cancer cells.However,the low water solubility of both compounds hinders their clinical applications.In this study,rod-shaped nanoparticles(NPs)self-assembled from LUT and GA were designed to enhance drug solubility and tumor-targeting capability.We verified that the assembly mechanism of the NPs was π-π stacking.These NPs significantly inhibited the proliferation of liver cancer cells while had no significant effect on normal liver cells.In a mouse model of liver cancer,these NPs demonstrated superior tumor-targeting ability due to the enhanced permeability and retention effect,and the affinity of GA for liver cancer cells,resulting in better therapeutic efficacy with lower systemic toxicity.Results of network pharmacology analysis showed that LUT and GA respectively targeted estrogen receptor 1(ESR1)protein and cyclin-dependent kinase 1(CDK1)protein to corporately induce tumor cell cycle arrest,which induced the inhibition of tumor cell proliferation.In conclusion,this study provides a novel reference for the treatment of liver cancer.展开更多
Fertilization or atmospheric deposition of nitrogen(N)and phosphorus(P)to terrestrial ecosystems can alter soil N(P)availability and the nature of nutrient limitation for plant growth.Changing the allocation of leaf P...Fertilization or atmospheric deposition of nitrogen(N)and phosphorus(P)to terrestrial ecosystems can alter soil N(P)availability and the nature of nutrient limitation for plant growth.Changing the allocation of leaf P fractions is potentially an adaptive strategy for plants to cope with soil N(P)availability and nutrient-limiting conditions.However,the impact of the interactions between imbalanced anthropogenic N and P inputs on the concentrations and allocation proportions of leaf P fractions in forest woody plants remains elusive.We conducted a metaanalysis of data about the concentrations and allocation proportions of leaf P fractions,specifically associated with individual and combined additions of N and P in evergreen forests,the dominant vegetation type in southern China where the primary productivity is usually considered limited by P.This assessment allowed us to quantitatively evaluate the effects of N and P additions alone and interactively on leaf P allocation and use strategies.Nitrogen addition(exacerbating P limitation)reduced the concentrations of leaf total P and different leaf P fractions.Nitrogen addition reduced the allocation to leaf metabolic P but increased the allocation to other fractions,while P addition showed opposite trends.The simultaneous additions of N and P showed an antagonistic(mutual suppression)effect on the concentrations of leaf P fractions,but an additive(summary)effect on the allocation proportions of leaf P fractions.These results highlight the importance of strategies of leaf P fraction allocation in forest plants under changes in environmental nutrient availability.Importantly,our study identified critical interactions associated with combined N and P inputs that affect leaf P fractions,thus aiding in predicting plant acclimation strategies in the context of intensifying and imbalanced anthropogenic nutrient inputs.展开更多
In the practice of healthcare,patient-reported outcomes(PROs)and PRO measures(PROMs)are used as an attempt to observe the changes in complex clinical situations.They guide us in making decisions based on the evidence ...In the practice of healthcare,patient-reported outcomes(PROs)and PRO measures(PROMs)are used as an attempt to observe the changes in complex clinical situations.They guide us in making decisions based on the evidence regarding patient care by recording the change in outcomes for a particular treatment to a given condition and finally to understand whether a patient will benefit from a particular treatment and to quantify the treatment effect.For any PROM to be usable in health care,we need it to be reliable,encapsulating the points of interest with the potential to detect any real change.Using structured outcome measures routinely in clinical practice helps the physician to understand the functional limitation of a patient that would otherwise not be clear in an office interview,and this allows the physician and patient to have a meaningful conver-sation as well as a customized plan for each patient.Having mentioned the rationale and the benefits of PROMs,understanding the quantification process is crucial before embarking on management decisions.A better interpretation of change needs to identify the treatment effect based on clinical relevance for a given condition.There are a multiple set of measurement indices to serve this effect and most of them are used interchangeably without clear demarcation on their differences.This article details the various quantification metrics used to evaluate the treatment effect using PROMs,their limitations and the scope of usage and implementation in clinical practice.展开更多
An analytical DC model accounting for the self-heating effect of polycrystalline silicon thin-film transistors（poly-Si TFTs） is presented.In deriving the model for the self-heating effect, the temperature dependence...An analytical DC model accounting for the self-heating effect of polycrystalline silicon thin-film transistors（poly-Si TFTs） is presented.In deriving the model for the self-heating effect, the temperature dependence of the effective mobility is studied in detail.Based on the mobility model and a first order approximation, a closed-form analytical drain current model considering the self-heating effect is derived.Compared with the available experimental data, the proposed model, which includes the self-heating and kink effects, provides an accurate description of the output characteristics over the linear, the saturation, and the kink regimes.展开更多
Structural regulation of Pd-based electrocatalytic hydrodechlorination(EHDC)catalyst for constructing high-efficient cathode materials with low noble metal content and high atom utilization is crucial but still challe...Structural regulation of Pd-based electrocatalytic hydrodechlorination(EHDC)catalyst for constructing high-efficient cathode materials with low noble metal content and high atom utilization is crucial but still challenging.Herein,a support electron inductive effect of Pd-Mn/Ni foam catalyst was proposed via in-situ Mn doping to optimize the electronic structure of the Ni foam(NF),which can inductive regulation of Pd for improving the EHDC performance.The mass activity and current efficiency of Pd-Mn/NF catalyst are 2.91 and 1.34 times superior to that of Pd/NF with 2,4-dichlorophenol as model compound,respectively.The Mn-doped interlayer optimized the electronic structure of Pd by bringing the d-state closer to the Fermi level than Pd on the NF surface,which optimizied the binding of EHDC intermediates.Additionally,the Mn-doped interlayer acted as a promoter for generating H∗and accelerating the EHDC reaction.This work presents a simple and effective regulation strategy for constructing high-efficient cathode catalyst for the EHDC of chlorinated organic compounds.展开更多
Low-electrode capacitive deionization(FCDI)is an emerging desalination technology with great potential for removal and/or recycling ions from a range of waters.However,it still suffers from inefficient charge transfer...Low-electrode capacitive deionization(FCDI)is an emerging desalination technology with great potential for removal and/or recycling ions from a range of waters.However,it still suffers from inefficient charge transfer and ion transport kinetics due to weak turbulence and low electric intensity in flow electrodes,both restricted by the current collectors.Herein,a new tip-array current collector(designated as T-CC)was developed to replace the conventional planar current collectors,which intensifies both the charge transfer and ion transport significantly.The effects of tip arrays on flow and electric fields were studied by both computational simulations and electrochemical impedance spectroscopy,which revealed the reduction of ion transport barrier,charge transport barrier and internal resistance.With the voltage increased from 1.0 to 1.5 and 2.0 V,the T-CC-based FCDI system(T-FCDI)exhibited average salt removal rates(ASRR)of 0.18,0.50,and 0.89μmol cm^(-2) min^(-1),respectively,which are 1.82,2.65,and 2.48 folds higher than that of the conventional serpentine current collectors,and 1.48,1.67,and 1.49 folds higher than that of the planar current collectors.Meanwhile,with the solid content in flow electrodes increased from 1 to 5 wt%,the ASRR for T-FCDI increased from 0.29 to 0.50μmol cm^(-2) min^(-1),which are 1.70 and 1.67 folds higher than that of the planar current collectors.Additionally,a salt removal efficiency of 99.89%was achieved with T-FCDI and the charge efficiency remained above 95%after 24 h of operation,thus showing its superior long-term stability.展开更多
Objective The use of lasers has been an important part of urology in the treatment of stone and prostate disease.The thermal effects of lasers in lithotripsy have been a subject of debate over the years.The objective ...Objective The use of lasers has been an important part of urology in the treatment of stone and prostate disease.The thermal effects of lasers in lithotripsy have been a subject of debate over the years.The objective of this review was to assess the current state of knowledge available on the thermal effects of lasers in lithotripsy,as well as explore any new areas where studies are needed.Methods In August 2022,a keyword search on Google Scholar,PubMed,and Scopus for all papers containing the phrases“thermal effects”AND“laser”AND“lithotripsy”AND“urology”was done followed by citation jumping to other studies pertaining to the topic and 35 relevant papers were included in our study.The data from relevant papers were segregated into five groups according to the factor studied and type of study,and tables were created for a comparison of data.Results Temperature above the threshold of 43℃ was reached only when the power was>40 W and when there was adequate irrigation(at least 15–30 mL/min).Shorter lasing time divided by lithotripsy time or operator duty cycles less than 70%also resulted in a smaller temperature rise.Conclusion At least eight factors modify the thermal effects of lasers,and most importantly,the use of chilled irrigation at higher perfusion rates,lower power settings of<40 W,and with a shorter operator duty cycle will help to prevent thermal injuries from occurring.Stones impacted in the ureter or pelvi-ureteric junction further increase the probability of thermal injuries during laser firing.展开更多
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.
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supported by National Natural Science Foundation of China (No.10905044)
文摘For exploiting advantages of electron beam air plasma in some unusual applications, a Monte Carlo （MC） model coupled with heat transfer model is established to simulate the characteristics of electron beam air plasma by considering the self-heating effect. Based on the model, the electron beam induced temperature field and the related plasma properties are investigated. The results indicate that a nonuniform temperature field is formed in the electron beam plasma region and the average temperature is of the order of 600 K. Moreover, much larger volume pear-shaped electron beam plasma is produced in hot state rather than in cold state. The beam ranges can, with beam energies of 75 keV and 80 keV, exceed 1.0 m and 1.2 m in air at pressure of 100 torr, respectively. Finally, a well verified formula is obtained for calculating the range of high energy electron beam in atmosphere.
基金Project supported by the National Natural Science Foundation of China (Grant No 60606022)the State Key Development Program for Basic Research of China (Grant No 51327010101)Xi’an Applied Materials Innovation Fund,China (Grant No XA-AM-200702)
文摘A thermal model of 4H-SiC MESFET is developed based on the temperature dependences of material parameters and three-region I - V model. The static current characteristics of 4H-SiC MESFET have been obtained with the consideration of the self-heating effect on related parameters including electron mobility, saturation velocity and thermal conductivity. High voltage performances are analysed using equivalent thermal conductivity model. Using the physicalbased simulations, we studied the dependence of self-heating temperature on the thickness and doping of substrate. The obtained results can be used for optimization of the thermal design of the SiC-based high-power field effect transistors.
基金Supported by the Special Funds for Major State Basic Research Projects(NO.G20000365)and the National Natural Science Foundation of China(No.90101012)
文摘An inherent self-heating effect of the silicon-on-insulator (SOI) devices limits their application at high current levels. In this paper a novel solution to reduce the self-heating effect is proposed, based on N+ and O+ co-implantation into silicon wafer to form a new buried layer structure. This new structure was simulated using Medici program, and the temperature distribution and output characteristics were compared with those of the conventional SOI counterparts. As expected, a reduction of self-heating effect in the novel SOI device was observed.
基金Supported by the Special Funds for Major State Basic Research Projects (No.G2000036506)the National Natural Science Foundation of China (No. 60476006)
文摘Compared with bulk-silicon technology, silicon-on-insulator (SOI) technology possesses many advan-tages but it is inevitable that the buried silicon dioxide layer also thermally insulates the metal – oxide – silicon field-effect transistors (MOSFETs) from the bulk due to the low thermal conductivity. One of the alternative insulator to replace the buried oxide layer is aluminum nitride (AlN), which has a thermal conductivity that is about 200 times higher than that of SiO2 (320 W·m ? 1·K? 1 versus 1.4 W·m? 1·K? 1). To investigate the self-heating effects of small-size MOSFETs fabricated on silicon-on-aluminum nitride (SOAN) substrate, a two-dimensional numerical analysis is performed by using a device simulator called MEDICI run on a Solaris workstation to simulate the electri-cal characteristics and temperature distribution by comparing with those of bulk and standard SOI MOSFETs. Our study suggests that AlN is a suitable alternative to silicon dioxide as a buried dielectric in SOI and expands the appli-cations of SOI to high temperature conditions.
基金supported by the National Key Technology Research and Development Program of China(No.2016YFA0202101)the National Natural Science Foundation of China(Nos.61421005,61604005)+1 种基金the National High-Tech R&D Program(863 Program)(No.2015AA016501)The simulation was carried out at National Supercomputer Center in Tianjin,with Tian He-1(A)
文摘We use an electro-thermal coupled Monte Carlo simulation framework to investigate the self-heating effect（SHE） in 14 nm bulk n Fin FETs with ambient temperature（TA） from 220 to 400 K. Based on this method, nonlocal heat generation can be achieved. Contact thermal resistances of Si/Metal and Si/Si O_2 are selected to ensure that the source and drain heat dissipation paths are the first two heat dissipation paths. The results are listed below：（i） not all input power（Q_（input） turns into heat generation in the device region and some is taken out by the thermal non-equilibrium carriers, owing to the serious non-equilibrium transport;（ii） a higher TA leads to a larger ratio of input power turning into heat generation in the device region at the same operating voltages;（iii） SHE can lead to serious degradation in the carrier transport, which will increase when TA increases;（iv） the current degradation can be 8.9% when Vds = 0.7 V, Vgs = 1 V and TA = 400 K;（v） device thermal resistance（Rth） increases with increasing of TA, which is seriously impacted by the non-equilibrium transport. Hence, the impact of TA should be carefully considered when investigating SHE in nanoscale devices.
基金Project supported by the National Natural Science Foundation of China(Nos.60976068,60936005)the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education of China(No.708083)the Specialized Research Fund for the Doctoral Program of Higher Education,China(No.200807010010)
文摘To reduce the self-heating effect of strained Si grown on relaxed SiGe-on-insulator（SGOI） n-type metal-oxide-semiconductor field-effect transistors（nMOSFETs）,this paper proposes a novel device called double step buried oxide（BOX） SGOI,investigates its electrical and thermal characteristics,and analyzes the effect of self-heating on its electrical parameters.During the simulation of the device,a low field mobility model for strained Si MOSFETs is established and reduced thermal conductivity resulting from phonon boundary scattering is considered.A comparative study of SGOI nMOSFETs with different BOX thicknesses under channel and different channel strains has been performed.By reducing moderately the BOX thickness under the channel,the channel temperature caused by the self-heating effect can be effectively reduced.Moreover,mobility degradation,off state current and a short-channel effect such as drain induced barrier lowering can be well suppressed.Therefore,SGOI MOSFETs with a thinner BOX under the channel can improve the overall performance and long-term reliability efficiently.
基金supported by the National Natural Science Foundation of China(No.60606006)the Key Science&Technology Special Project of Shaanxi Province,China(No.2011KTCQ01-19)the National Defense Pre-Research Foundation of China(No.9140A23060111)
文摘Considering the self-heating effect, an accurate expression for the global interconnection resistance per unit length in terms of interconnection wire width and spacing is presented. Based on the proposed resistance model and according to the trade-off theory, a novel optimization analytical model of delay, power dissipation and bandwidth is derived. The proposed optimal model is verified and compared based on 90 nm, 65 nm and 40 nm CMOS technologies. It can be found that more optimum results can be easily obtained by the proposed model. This optimization model is more accurate and realistic than the conventional optimization models, and can be integrated into the global interconnection design ofnano-scale integrated circuits.
基金National Natural Science Foundation of China,12272305,Yahui Zhang,12372123,Xiaojun GuBasic Research Program,JCKY2022603C016,Xiaojun Gu。
文摘This paper aims to seek expedited fatigue analysis methods using the infrared self-heating technique.The fatigue analysis of NiTi shape memory alloys is obtained through a hybrid approach:fatigue tests to failure yield relatively shorter fatigue lives,while determining the fatigue limit,normally involving extremely high cycles approaching 107 cycles,is directly achieved via self-heating tests.This methodology significantly reduces testing cycles,costing only a fraction of the several-thousand-cycle tests typically required.The validity of this approach is successfully demonstrated through fatigue testing of 18Ni steel:the entire S–N curve is examined using the traditional fatigue test until a life of up to 10^(7) cycles,and the indicated fatigue limit agrees well with the one directly determined through the self-heating method.Subsequently,this developed approach is applied to the fatigue analysis of shape memory alloys under complex loading,enabling the concurrent estimation of the limits of phase transformation-dominated low-cycle fatigue and high-cycle fatigue in the elastic regime on a single specimen.The results obtained align well with other supporting evidence.
基金support of the National Natural Science Foundation of China(Grant Nos.52192611,51872031,61904013,and 62405157)China Postdoctoral Science Foundation(Nos.2023M741890 and GZC20231215)the Fundamental Research Funds for the Central Universities.
文摘The flexoelectric effect refers to the electromechanical coupling between electric polarization and mechanical strain gradient.It universally exists in a variety of materials in any space group,such as liquid crystals,dielectrics,biological materials,and semiconductors.Because of its unique size effect,nanoscale flexoelectricity has shown novel phenomena and promising applications in electronics,optronics,mechatronics,and photovoltaics.In this review,we provide a succinct report on the discovery and development of the flexoelectric effect,focusing on flexoelectric materials and related applications.Finally,we discuss recent flexoelectric research progress and still‐unsolved problems.
文摘Agricultural intensification has led to an increase in monoculture and the use of chemical pesticides,resulting in a decline in biodiversity and a reduction in ecosystem services,particularly biological pest management.However,studies have shown that agroforestry can not only improve land productivity and biodiversity but also regulate some ecosystem services.This study reviews the impacts of physical and biological factors on herbivorous pests,parasites,and predatory natural enemies in fruit-crop agroforestry systems.Fruit-crop agroforestry systems provide high spatial heterogeneity by altering crop layouts,regulating the microclimate and soil quality,and offering food resources and shelter for natural enemies,thus promoting biological pest control.This enhances biological control and makes the agrocomplex system an effective tool for sustainable agriculture.Our research shows that volatile plant substances attract or repel pests and natural enemies based on the characteristics of the insects themselves.When scientifically designed,fruit-crop agroforestry systems provide high spatial heterogeneity and favorable microclimatic conditions,which enhance biological pest control and make the agroforestry system an effective tool for sustainable agriculture.Our research shows that fruit-crop agroforestry systems can provide richer food resources and habitat,enhancing biological pest control and improving pest management.
基金the financial support from Henan Province Natural Science Foundation(No.252300420583)Henan Provincial Science and Technology Research Project(Nos.242102310455,242102310473,242102310517)the Key Project of Science and Technology Research funded by the Henan Provincial Department of Education(No.24A350002)。
文摘Liver cancer is the fourth cause of cancer-related deaths and the primary cause of death in patients with compensated cirrhosis.In recent years,the role of traditional Chinese medicine in the treatment of liver cancer has attracted more and more attention and recognition.Luteolin(LUT)and glycyrrhetinic(GA)are natural compounds extracted from Chinese herbal medicine.LUT exhibits various biological activity including anti-inflammatory,antibacterial,antiviral,anti-tumor,and neuroprotective effects.GA significantly inhibits the growth and metastasis of cancer cells.However,the low water solubility of both compounds hinders their clinical applications.In this study,rod-shaped nanoparticles(NPs)self-assembled from LUT and GA were designed to enhance drug solubility and tumor-targeting capability.We verified that the assembly mechanism of the NPs was π-π stacking.These NPs significantly inhibited the proliferation of liver cancer cells while had no significant effect on normal liver cells.In a mouse model of liver cancer,these NPs demonstrated superior tumor-targeting ability due to the enhanced permeability and retention effect,and the affinity of GA for liver cancer cells,resulting in better therapeutic efficacy with lower systemic toxicity.Results of network pharmacology analysis showed that LUT and GA respectively targeted estrogen receptor 1(ESR1)protein and cyclin-dependent kinase 1(CDK1)protein to corporately induce tumor cell cycle arrest,which induced the inhibition of tumor cell proliferation.In conclusion,this study provides a novel reference for the treatment of liver cancer.
基金supported by the National Natural Science Foundation of China(No.41473068)supported by China Postdoctoral Science Foundation(No.2022M722667)。
文摘Fertilization or atmospheric deposition of nitrogen(N)and phosphorus(P)to terrestrial ecosystems can alter soil N(P)availability and the nature of nutrient limitation for plant growth.Changing the allocation of leaf P fractions is potentially an adaptive strategy for plants to cope with soil N(P)availability and nutrient-limiting conditions.However,the impact of the interactions between imbalanced anthropogenic N and P inputs on the concentrations and allocation proportions of leaf P fractions in forest woody plants remains elusive.We conducted a metaanalysis of data about the concentrations and allocation proportions of leaf P fractions,specifically associated with individual and combined additions of N and P in evergreen forests,the dominant vegetation type in southern China where the primary productivity is usually considered limited by P.This assessment allowed us to quantitatively evaluate the effects of N and P additions alone and interactively on leaf P allocation and use strategies.Nitrogen addition(exacerbating P limitation)reduced the concentrations of leaf total P and different leaf P fractions.Nitrogen addition reduced the allocation to leaf metabolic P but increased the allocation to other fractions,while P addition showed opposite trends.The simultaneous additions of N and P showed an antagonistic(mutual suppression)effect on the concentrations of leaf P fractions,but an additive(summary)effect on the allocation proportions of leaf P fractions.These results highlight the importance of strategies of leaf P fraction allocation in forest plants under changes in environmental nutrient availability.Importantly,our study identified critical interactions associated with combined N and P inputs that affect leaf P fractions,thus aiding in predicting plant acclimation strategies in the context of intensifying and imbalanced anthropogenic nutrient inputs.
文摘In the practice of healthcare,patient-reported outcomes(PROs)and PRO measures(PROMs)are used as an attempt to observe the changes in complex clinical situations.They guide us in making decisions based on the evidence regarding patient care by recording the change in outcomes for a particular treatment to a given condition and finally to understand whether a patient will benefit from a particular treatment and to quantify the treatment effect.For any PROM to be usable in health care,we need it to be reliable,encapsulating the points of interest with the potential to detect any real change.Using structured outcome measures routinely in clinical practice helps the physician to understand the functional limitation of a patient that would otherwise not be clear in an office interview,and this allows the physician and patient to have a meaningful conver-sation as well as a customized plan for each patient.Having mentioned the rationale and the benefits of PROMs,understanding the quantification process is crucial before embarking on management decisions.A better interpretation of change needs to identify the treatment effect based on clinical relevance for a given condition.There are a multiple set of measurement indices to serve this effect and most of them are used interchangeably without clear demarcation on their differences.This article details the various quantification metrics used to evaluate the treatment effect using PROMs,their limitations and the scope of usage and implementation in clinical practice.
文摘An analytical DC model accounting for the self-heating effect of polycrystalline silicon thin-film transistors（poly-Si TFTs） is presented.In deriving the model for the self-heating effect, the temperature dependence of the effective mobility is studied in detail.Based on the mobility model and a first order approximation, a closed-form analytical drain current model considering the self-heating effect is derived.Compared with the available experimental data, the proposed model, which includes the self-heating and kink effects, provides an accurate description of the output characteristics over the linear, the saturation, and the kink regimes.
基金supported by the National Natural Science Foundation of China(Nos.22178388 and 22108306)Taishan Scholars Program of Shandong Province(No.tsqn201909065)Chongqing Science and Technology Bureau(No.cstc2019jscx-gksb X0032).
文摘Structural regulation of Pd-based electrocatalytic hydrodechlorination(EHDC)catalyst for constructing high-efficient cathode materials with low noble metal content and high atom utilization is crucial but still challenging.Herein,a support electron inductive effect of Pd-Mn/Ni foam catalyst was proposed via in-situ Mn doping to optimize the electronic structure of the Ni foam(NF),which can inductive regulation of Pd for improving the EHDC performance.The mass activity and current efficiency of Pd-Mn/NF catalyst are 2.91 and 1.34 times superior to that of Pd/NF with 2,4-dichlorophenol as model compound,respectively.The Mn-doped interlayer optimized the electronic structure of Pd by bringing the d-state closer to the Fermi level than Pd on the NF surface,which optimizied the binding of EHDC intermediates.Additionally,the Mn-doped interlayer acted as a promoter for generating H∗and accelerating the EHDC reaction.This work presents a simple and effective regulation strategy for constructing high-efficient cathode catalyst for the EHDC of chlorinated organic compounds.
基金supported by the Shenzhen Science and Technology Program(JCYJ20230808105111022,JCYJ20220818095806013)Natural Science Foundation of Guangdong(2023A1515012267)+1 种基金the National Natural Science Foundation of China(22178223)the Royal Society/NSFC cost share program(IEC\NSFC\223372).
文摘Low-electrode capacitive deionization(FCDI)is an emerging desalination technology with great potential for removal and/or recycling ions from a range of waters.However,it still suffers from inefficient charge transfer and ion transport kinetics due to weak turbulence and low electric intensity in flow electrodes,both restricted by the current collectors.Herein,a new tip-array current collector(designated as T-CC)was developed to replace the conventional planar current collectors,which intensifies both the charge transfer and ion transport significantly.The effects of tip arrays on flow and electric fields were studied by both computational simulations and electrochemical impedance spectroscopy,which revealed the reduction of ion transport barrier,charge transport barrier and internal resistance.With the voltage increased from 1.0 to 1.5 and 2.0 V,the T-CC-based FCDI system(T-FCDI)exhibited average salt removal rates(ASRR)of 0.18,0.50,and 0.89μmol cm^(-2) min^(-1),respectively,which are 1.82,2.65,and 2.48 folds higher than that of the conventional serpentine current collectors,and 1.48,1.67,and 1.49 folds higher than that of the planar current collectors.Meanwhile,with the solid content in flow electrodes increased from 1 to 5 wt%,the ASRR for T-FCDI increased from 0.29 to 0.50μmol cm^(-2) min^(-1),which are 1.70 and 1.67 folds higher than that of the planar current collectors.Additionally,a salt removal efficiency of 99.89%was achieved with T-FCDI and the charge efficiency remained above 95%after 24 h of operation,thus showing its superior long-term stability.
文摘Objective The use of lasers has been an important part of urology in the treatment of stone and prostate disease.The thermal effects of lasers in lithotripsy have been a subject of debate over the years.The objective of this review was to assess the current state of knowledge available on the thermal effects of lasers in lithotripsy,as well as explore any new areas where studies are needed.Methods In August 2022,a keyword search on Google Scholar,PubMed,and Scopus for all papers containing the phrases“thermal effects”AND“laser”AND“lithotripsy”AND“urology”was done followed by citation jumping to other studies pertaining to the topic and 35 relevant papers were included in our study.The data from relevant papers were segregated into five groups according to the factor studied and type of study,and tables were created for a comparison of data.Results Temperature above the threshold of 43℃ was reached only when the power was>40 W and when there was adequate irrigation(at least 15–30 mL/min).Shorter lasing time divided by lithotripsy time or operator duty cycles less than 70%also resulted in a smaller temperature rise.Conclusion At least eight factors modify the thermal effects of lasers,and most importantly,the use of chilled irrigation at higher perfusion rates,lower power settings of<40 W,and with a shorter operator duty cycle will help to prevent thermal injuries from occurring.Stones impacted in the ureter or pelvi-ureteric junction further increase the probability of thermal injuries during laser firing.
