The atom-bond sum-connectivity(ABS)index,put forward by[J.Math.Chem.,2022,60(10):20812093],exhibits a strong link with the acentric factor of octane isomers.The experimental physico-chemical properties of octane isome...The atom-bond sum-connectivity(ABS)index,put forward by[J.Math.Chem.,2022,60(10):20812093],exhibits a strong link with the acentric factor of octane isomers.The experimental physico-chemical properties of octane isomers,such as boiling point,of formation are found to be better measured by the ABS index than by the Randi,atom-bond connectivity(ABC),and sum-connectivity(SC)indices.One important source of information for researching the molecular structure is the bounds for its topological indices.The extrema of the ABS index of the line,total,and Mycielski graphs are calculated in this work.Moreover,the pertinent extremal graphs were illustrated.展开更多
In this study,polyacrylic acid(PAA)films were employed as a model system,and a series of PAA films with tunable water wettability was systematically prepared by varying molecular weight and curing temperature.Using at...In this study,polyacrylic acid(PAA)films were employed as a model system,and a series of PAA films with tunable water wettability was systematically prepared by varying molecular weight and curing temperature.Using attenuated total reflectance Fourier-transform infrared spectroscopy(ATR-FTIR),the molecular configurations of surface carboxyl groups(COOH),free carboxyl(COOH_(f))and hydrogen-bonded carboxyl(COOH_(HB),were directly correlated with the polar component of surface energy(γ^(s,p)).By decomposing theγ^(s,p)values of the PAA thin films as a sum of the contributions of COOH_(f)and COOH_(H B),the intrinsic polar component of surface energy of COOH_(H B)(γ_(H B)^(s,p*))was quantified for the first time as 8.34 mN/m,significantly lower than that of COOH_(f)(γ_(f)^(s,p*)=34 mN/m).This result highlights that hydrogen bonding markedly reduces theγ^(s,p),providing a rational explanation for the relatively large water contact angle observed on PAA thin films.Furthermore,it establishes a thermodynamic basis for estimating the fraction of surface COOH_(H B)groups(f H B)from wettability measurements.Further extension of the model to carboxyl-terminated self-assembled monolayers(COOH-SAMs)revealed that surface COOH density(ΣCOOH)critically regulates wetting behavior:whenΣCOOH ranges from 4.30 to 5.25 nm^(-2),COOH groups predominantly exist in a free state and facilitate effective hydration layers,thereby promoting superhydrophilicity.Overall,this study not only establishes a unified thermodynamic framework linking surface COOH configurations to macroscopic wettability,but also validates its universality by extending it to COOH-SAMs systems,thereby providing a unified theoretical framework for the controllable design of hydrophilicity in various COOH-functionalized surfaces.展开更多
Pine and oak forests have great relevance worldwide since they are recognized for the benefits and services they provide.Grazing can affect nitrogen reserves in forest trees in complex ways,the effects manifest throug...Pine and oak forests have great relevance worldwide since they are recognized for the benefits and services they provide.Grazing can affect nitrogen reserves in forest trees in complex ways,the effects manifest through changes in the soil,vegetation,and the nitrogen cycle.Nature tourism can have negative impacts on tree physiology.These impacts affect vital processes such as photosynthesis,respiration,water relations,and metabolism.This study was developed in order to determine whether natural populations of pine(Pinus cembroides Zucc.)and oak(Quercus grisea Liebm.)are affected physiologically by grazing and tourism during the stages of development and dormancy,specifically in nitrogenous compounds(Total Soluble Proteins[TSP]and Total Amino Acids[TAA])stocked in perennial organs(stem and roots)and leaves.The results showed that grazing and tourism have both negative and favorable effects on the concentrations of nitrogen compounds.The highest concentration of nitrogenous compounds was found in oak compared to pine.The root,trunk,and leaves in the grazed and non-impacted sites showed the highest concentrations of nitrogen compounds compared to the tourism-impacted site.Pine is the species most affected by anthropogenic processes(grazing and tourism)in the stages of development and dormancy,since the concentrations of nitrogenous compounds were lower compared to oak.展开更多
ADPr-ATP is a natural nucleotide with three sugar rings and five pentavalent phosphorus,and can be produced through TIR-catalyzed ADP-ribosylation reactions for plant immunity.Here,we report the first total synthesis ...ADPr-ATP is a natural nucleotide with three sugar rings and five pentavalent phosphorus,and can be produced through TIR-catalyzed ADP-ribosylation reactions for plant immunity.Here,we report the first total synthesis of ADPr-ATP(1)with a total yield of 6.4%through 14 steps,featuring late-stage P(V)−N activation reaction of pyrophosphate(4)and 5′-phosphoromorpholidate(25).The protected adenosine 5′-phosphoromorpholidate(24)was prepared on the basis of a scalable to adenosine 5′′-monophosphate(2).The construction of P(V)−N bond in phosphoramidate is esteemed as a critical step as they are sufficiently stable in deprotection reactions.The chemical synthesis of ADPr-ATP can offer an appealing alternative to traditional enzymatic synthesis and fractionation methods.Furthermore,the pRib-AMP and its prodrug are also synthesized to evaluate cytotoxicity and anti-influenza activity in vitro.展开更多
This study investigates the distinct impacts of eastern Pacific(EP)and central Pacific(CP)El Niño events on winter shortwave solar radiation(SSR)in southern China,revealing different spatial distributions and und...This study investigates the distinct impacts of eastern Pacific(EP)and central Pacific(CP)El Niño events on winter shortwave solar radiation(SSR)in southern China,revealing different spatial distributions and underlying mechanisms.The results show that,during the developing winter of EP El Niño,significant SSR reductions occur in southwestern China and the east coast of southern China due to a strong,zonally extended Northwest Pacific anticyclone that transports moisture from the tropical Northwest Pacific and North Indian Ocean,while the northeast of southern China experiences a weak increase in SSR.In contrast,during the developing winter of CP El Niño,SSR decreases in the east of southern China with a significant decrease in the lower basin of the Yangtze River but an increase in the west of southern China with a remarkable increase in eastern Yunnan.The pronounced east-west dipole pattern in SSR anomalies is driven by a meridionally elongated Northwest Pacific anticyclone,which enhances northward moisture transport to the east of southern China while leaving western areas drier.Further research reveals that distinct moisture anomalies during the developing winter of EP and CP events result in divergent SSR distributions across southern China,primarily through modulating the total cloud cover.These findings highlight the critical need to differentiate between El Niño types when predicting medium and long-term variability of radiation in southern China.展开更多
Objective:To investigate the related factors of motility after total hip arthroplasty(THA).Methods:The convenience sampling method was used to include 213 patients receiving THA in our hospital from June 2020 to June ...Objective:To investigate the related factors of motility after total hip arthroplasty(THA).Methods:The convenience sampling method was used to include 213 patients receiving THA in our hospital from June 2020 to June 2023.They were divided into 2 groups according to the occurrence of kinesiophobia after THA.The demographic data of the 2 groups were analyzed by single-factor analysis.The factors with statistically significant differences were analyzed by binary logistic regression as independent variables.Finally,Spearman analysis was used to analyze the relationship between risk factors and the degree of kinesiophobia.Results:Among 213 THA patients,38 patients were diagnosed with kinetophobia,and the incidence of kinetophobia was 17.84%.visual analogue scale(VAS)and pain duration before operation were higher in patients with kinetophobia than in patients without kinetophobia.The scores of education level,self-efficacy,and social support were significantly lower than those of the non-phobia group,with statistical significance(P<0.05).Logistic regression analysis showed that VAS was a risk factor for kinetophobia after THA.Education level and self-efficacy were protective factors to reduce the occurrence of kinetophobia after THA(P<0.05).Spearman correlation analysis showed that the degree of pain(r=0.697,P<0.001)was positively correlated with the degree of kinetophobia,while the degree of education(r=-0.647,P<0.001)and self-efficacy(r=-0.756,P<0.001)were negatively correlated with the degree of kinetophobia.Conclusions:The degree of pain is a risk factor of kinesiophobia after THA,and it is positively correlated with the degree.Educational level and self-efficacy were protective factors to reduce the incidence of kinesiophobia and were negatively correlated with the degree of kinesiophobia.展开更多
BACKGROUND Aseptic loosening remains the leading cause of revision in primary total hip arthroplasty(pTHA).However,the literature demonstrates significant variability regarding the relative contributions of different ...BACKGROUND Aseptic loosening remains the leading cause of revision in primary total hip arthroplasty(pTHA).However,the literature demonstrates significant variability regarding the relative contributions of different factors.AIM To investigate the key determinants of aseptic loosening,we performed a systematic review and meta-analysis.METHODS A comprehensive search of PubMed,Web of Science,EMBASE,and the Cochrane Library was conducted,encompassing studies from database inception to January 1,2025.Meta-analyses were performed to evaluate factors associated with aseptic loosening following pTHA.Inclusion and exclusion criteria were systematically applied at each stage to ensure methodological transparency and reproducibility.Study quality was assessed using standardized categories.Pooled odds ratio(OR)with corresponding 95%confidence interval were calculated with random-or fixed-effects models to generate reliability estimates,and study heterogeneity was visualized using forest plots.Ten factors,categorized into patient-,surgeon-,and device-related domains,were reviewed and meta-analyzed.Funnel plot analysis demonstrated a relatively symmetrical distribution,suggesting minimal publication bias.RESULTS A meta-analysis of 20 studies(520789 participants)found a pooled prevalence of 1.96%.Significant risk factors for aseptic loosening after pTHA included elevated body mass index(OR=1.116,P<0.001),higher Charlson comorbidity index(OR=1.378,P<0.001),prosthesis-related factors(OR=1.497,P<0.001),and adverse lifestyles(OR=2.198,P=0.037).Protective factors were non-white race(OR=0.445,P<0.001)and favorable genetics(OR=0.723,P<0.001).Male sex increased risk(OR=1.232,P=0.016),while age and anatomy were not significant.Surgical expertise showed a slight protective effect(OR=1.048,P<0.001).A comprehensive understanding of the modifiable and non-modifiable factors contributing to aseptic loosening after pTHA requires consideration of patient-related factors,surgical expertise,and prosthesis characteristics.CONCLUSION The identification of these factors is critical for risk mitigation.High-risk patients should receive targeted counseling regarding individualized profiles.Further studies are warranted to establish clearer causal relationships and identify additional contributing factors.展开更多
The carbon cycle stands as a cornerstone among the Earth's material cycles,carrying profound implications for global climate dynamics and humanity's sustenance and advancement.Additionally,nitrogen,as a vital ...The carbon cycle stands as a cornerstone among the Earth's material cycles,carrying profound implications for global climate dynamics and humanity's sustenance and advancement.Additionally,nitrogen,as a vital nutrient element,plays a pivotal role in biogeochemical processes,exerting significant influence on the ecological environment within watersheds.In this study,an analysis of the carbon(C)and nitrogen(N)components in the river water of 12 alpine basins on the eastern margin of the Tibetan Plateau(TP)reveals that the average dissolved organic carbon(DOC)concentration in the river water is 0.76±0.67 mg/L,indicating a lower level compared to the global river average organic carbon content.Specifically,the average DOC concentrations were 0.42±0.22 and 1.56±0.68 mg/L in the glacial and non-glacial basins,respectively.The average dissolved inorganic carbon(DIC)concentration in the eastern TP is 27.04±20.19 mg/L,with the lowest DIC observed at Dagu Glacier and the highest at Daxia River.Furthermore,the average dissolved total carbon(DTC)concentration in glacier river water was 18.87±12.65 mg/L,contrasting with 48.23±21.07 mg/L in non-glacial basins.The mean concentration of total nitrogen(TN)in the eastern TP averaged 0.97±0.54 mg/L,with the glacial basin registering 1.01±0.47 mg/L and the non-glacial basin at 0.89±0.70 mg/L.Evaluating the release fluxes of carbon and nitrogen across 12 river basins revealed a range of DTC emission fluxes from 0.32×10^(9)to 31.02×10^(9)g·C/a,with inorganic carbon comprising 71.0%to 99.5%.Consequently,the carbon emission flux for seven glacier basins totaled 15.91×10^(9)g·C/a,while for the five non-glacial river basins,it reached 87.37×10^(9)g·C/a.The total TN release fluxes across 12 small river basins amounted to 2.46×10^(9)g·N/a,with 0.84×10^(9)g·N/a released in glacial basins and 1.62×10^(9)g·N/a in the nonglacial basin.This study elucidates the spatial distribution and transport mechanisms of carbon and nitrogen elements within the glacial and downstream non-glacial basins,offering valuable insights into the biogeochemical cycles of carbon and nitrogen in the eastern Tibetan Plateau.展开更多
The micro-riblet structures have been demonstrated effective in controlling the Total Pressure Loss(TPL)of aero-engine blades.However,due to the considerable scale gap between micro-texture and an actual aero-engine b...The micro-riblet structures have been demonstrated effective in controlling the Total Pressure Loss(TPL)of aero-engine blades.However,due to the considerable scale gap between micro-texture and an actual aero-engine blade,wind tunnel tests and numerical simulations with massive grids directly describing the global flow field are costly for aerodynamic evaluation.Furthermore,the fine micro surface structure brings unavoidable manufacturing errors,and the probability prediction contributes to gaining the confidence interval of the results.Therefore,a novel relay-based probabilistic model for multi-fidelity scenarios in the TPL prediction of a compressor cascade with micro-riblet surfaces is proposed to trade off accuracy and efficiency.Combined with the low-fidelity flow data generated by an aerodynamic solution strategy using the boundary surrogate model and the high-fidelity flow data from the experiment,the relay-based modeling has been achieved through knowledge transferring,and the confidence interval can be provided by the Gaussian Process Regression(GPR)model.The TPL of compressor cascades with micro-riblet surfaces under different surface structures at March number Ma=0.64,0.74,0.84 have been evaluated using the Relay-Based Probabilistic(RBP)model.The results illustrate that the RBP model could provide higher accuracy than the Single-Fidelity-Data-Driven(SFDD)prediction model,which show the promising potential of multi-fidelity scenarios data fusion in the aerodynamic evaluation of multi-scale configurations.展开更多
BACKGROUND Salvage of the infected long stem revision total knee arthroplasty is challenging due to the presence of well-fixed ingrown or cemented stems.Reconstructive options are limited.Above knee amputation(AKA)is ...BACKGROUND Salvage of the infected long stem revision total knee arthroplasty is challenging due to the presence of well-fixed ingrown or cemented stems.Reconstructive options are limited.Above knee amputation(AKA)is often recommended.We present a surgical technique that was successfully used on four such patients to convert them to a knee fusion(KF)using a cephalomedullary nail.CASE SUMMARY Four patients with infected long stem revision knee replacements that refused AKA had a single stage removal of their infected revision total knee followed by a KF.They were all treated with a statically locked antegrade cephalomedullary fusion nail,augmented with antibiotic impregnated bone cement.All patients had successful limb salvage and were ambulatory with assistive devices at the time of last follow-up.All were infection free at an average follow-up of 25.5 months(range 16-31).CONCLUSION Single stage cephalomedullary nailing can result in a successful KF in patients with infected long stem revision total knees.展开更多
Objective:To systematically summarize and evaluate the evidence on discharge preparation services for patients undergoing total knee arthroplasty,providing an evidence-based foundation for developing scientific and st...Objective:To systematically summarize and evaluate the evidence on discharge preparation services for patients undergoing total knee arthroplasty,providing an evidence-based foundation for developing scientific and standardized discharge preparation intervention programs in clinical practice.Methods:Following the“5S”evidence model,literature such as guidelines,expert consensuses,evidence summaries and randomized controlled trials related to discharge preparation services for total knee arthroplasty patients were retrieved from relevant websites and databases,both domestic and international,from database inception to August 31,2025.Two researchers independently screened the literature,conducted quality appraisals,and extracted and synthesized the evidence.Results:A total of 15 articles were included,comprising 3 guidelines,4 expert consensuses,3 evidence summaries,3 systematic reviews and 2 randomized controlled trials.Ultimately,23 pieces of evidence were summarized across five aspects.Conclusion:This study synthesizes the evidence on discharge preparation services for patients undergoing total knee arthroplasty.It is recommended that healthcare professionals apply this evidence in clinical practice,considering specific circumstances and patient needs.展开更多
Leg-length discrepancy(LLD)in individuals experiencing total hip arthroplasty(THA)is related to a substantially higher fall risk,length of post-operative hospital in-patient stay,elevated implant-related adverse event...Leg-length discrepancy(LLD)in individuals experiencing total hip arthroplasty(THA)is related to a substantially higher fall risk,length of post-operative hospital in-patient stay,elevated implant-related adverse events,and earlier revision.Therefore,it is essential to try to avoid LLD when implanting a THA.Several studies focus on this issue,including the following:Accelerometer-based portable navigation system,preoperative digital templating,robot-assisted surgery,the anatomical marker positioning method(shoulder-to-shoulder)and the artificial intelligence-based three-dimensional planning software system.The aforementioned methods should be familiar to surgeons who perform THA procedures,as a fundamental objective of this surgical intervention is to avoid LLD.展开更多
The significant medicinal values associated with C19-hydroxylated steroids dictate a growing demand for new synthetic strategies that would provide facile access to these challenging targets.This review will encapsula...The significant medicinal values associated with C19-hydroxylated steroids dictate a growing demand for new synthetic strategies that would provide facile access to these challenging targets.This review will encapsulate the key synthetic strategies for C19-hydroxylated steroids,which include indirect C–H oxidation and direct C–H oxidation in semi-synthesis as well as total synthesis.展开更多
Foreign Trade Posts Strong Growth China’s foreign trade has posted a robust start to the year,with the total value of trade in goods surging 18.3 percent year on year in the January–February period,latest official d...Foreign Trade Posts Strong Growth China’s foreign trade has posted a robust start to the year,with the total value of trade in goods surging 18.3 percent year on year in the January–February period,latest official data showed.Data released on 10 March by the General Administration of Customs revealed that total goods trade value had reached 7.73 trillion yuan(about$1.12 trillion)during this period.展开更多
This study investigates the mechanisms of friction-induced vibration under periodic variations in stress distribution using an improved fretting friction model.A fretting friction test system integrated with a total r...This study investigates the mechanisms of friction-induced vibration under periodic variations in stress distribution using an improved fretting friction model.A fretting friction test system integrated with a total reflection method was developed to analyze interfacial contact behavior under dynamic loading conditions.An improved fretting friction model was established,incorporating three critical nonlinear parameters:the hysteretic friction coefficient,tangential stiffness fluctuations,and stress distribution.Through systematic validation,the model demonstrates high-fidelity replication of experimental steady-state amplitude-frequency responses.Key findings reveal that non-uniform stress distribution governs irregularities in the vibration response,and increased uniformity intensifies stick-slip instabilities.Near the stick-slip transition threshold,distinct vibration anomalies emerge due to the coupled effects of stress heterogeneity,friction hysteresis,and stiffness variations during state transitions.Furthermore,the magnitude of the normal contact force systematically alters the dominant interfacial contact mechanism.The different interfacial contact states at various frequencies lead to distinct steady-state responses.This shift elevates resonance frequencies and amplifies higher-order resonant peaks.The fretting friction model provides a predictive framework for vibration control under dynamic interfacial loading.展开更多
BACKGROUND The optimal surgical approach for patients with primary glenohumeral osteoarthritis(GHOA)and an intact rotator cuff remains debated.While anatomic total shoulder arthroplasty(TSA)has traditionally been favo...BACKGROUND The optimal surgical approach for patients with primary glenohumeral osteoarthritis(GHOA)and an intact rotator cuff remains debated.While anatomic total shoulder arthroplasty(TSA)has traditionally been favoured,reverse TSA(RTSA)is increasingly utilized.AIM To systematically compare the outcomes of RTSA and TSA in this specific patient population.METHODS A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines.Retrospective comparative studies evaluating RTSA and TSA in patients with GHOA and intact rotator cuff were included.Key outcomes assessed included complication and reoperation rates,patient-reported outcome measures(PROMs),and range of motion.Risk of bias was assessed using the Risk of Bias in Non-randomized Studies of Interventions tool.RESULTS Twelve studies encompassing 1608 patients(580 RTSA,1028 TSA)met inclusion criteria.RTSA was associated with a lower reoperation rate compared to TSA[odds ratio=0.37;95%confidence interval(CI):0.14-0.94;P value=0.04],while no significant difference in overall complication rates was observed(odds ratio=0.47;95%CI:0.19-1.16;P value=0.10).RTSA patients showed superior outcomes in University of California Los Angeles,Simple Shoulder Test,and Shoulder Pain and Disability Index scores;however,the differences did not exceed the minimal clinically important difference.TSA patients had significantly better external rotation(mean difference=-9.0°;95%CI:-13.21 to-5.02;P value<0.0001).No significant differences were found in other range of motion measures or satisfaction scores.The overall methodological quality of included studies was moderate to serious.CONCLUSION In patients with GHOA and an intact rotator cuff,RTSA may offer comparable or improved outcomes to TSA with lower reoperation rates and similar complication profiles.Functional outcomes favour RTSA in certain patientreported outcome measures,while TSA retains an advantage in external rotation.Surgical decision-making should remain individualized based on patient characteristics and functional demands.展开更多
AIM:To evaluate the agreement of axial length(AL),anterior chamber parameters,and total cornea power obtained by swept-source optical coherence tomography(SS-OCT)-based and Scheimpflug-based optical biometers in myopi...AIM:To evaluate the agreement of axial length(AL),anterior chamber parameters,and total cornea power obtained by swept-source optical coherence tomography(SS-OCT)-based and Scheimpflug-based optical biometers in myopic children.METHODS:AL,steep keratometry(K),flat K,posterior corneal keratometry(PK),total keratometry(TK),anterior chamber depth(ACD),horizontal corneal diameter(CD),and central corneal thickness(CCT)were obtained using IOL Master 700 and Pentacam AXL.The agreement between the devices was evaluated using intraclass correlation coefficients(ICC),Bland-Altman plots,and astigmatism vector analysis.RESULTS:Totally 175 myopic children(48.5%male)with a mean age of 10.29±2.14y were enrolled.The ICC and Bland-Altman plots indicated a satisfactory agreement for AL,ACD,and CCT.The mean difference in CD of-0.31±0.30 mm was considered clinically significant(>0.2 mm).Additionally,measurements of K and TK obtained from the IOL Master 700 showed good agreement.Nevertheless,there were clinically significant differences observed in PK,simulated keratometry(simK),total cornea power,and astigmatism(at least 10%of the cases with a difference of>10 degrees in meridian)between the two devices.CONCLUSION:The study findings demonstrate a significant difference in K,PK,astigmatism,and CD,indicating that the two optical biometers cannot be considered interchangeable.Therefore,it is recommended to utilize one kind device for follow-up examinations in myopic children.展开更多
BACKGROUND Medial dished(MD)liner designs for cruciate-retaining(CR)total knee arthroplasty(TKA)are a relatively novel development.MD tibial inserts have a more constraining medial side,which allows for more similar k...BACKGROUND Medial dished(MD)liner designs for cruciate-retaining(CR)total knee arthroplasty(TKA)are a relatively novel development.MD tibial inserts have a more constraining medial side,which allows for more similar kinematics and function to a native knee.AIM To evaluate the clinical results and patient-reported outcomes after CR TKA procedures utilizing a kinematically designed medial dish system.METHODS A multicenter,retrospective cohort review of 139 primary elective TKAs utilizing a kinematically designed CR Knee System(JOURNEY™II CR MD;Smith and Nephew,Memphis,TN,United States)at three different institutions with a minimum of two years of follow-up.Demographic information,clinical outcomes,and patient-reported outcome measures were collected and analyzed.RESULTS With up to 3.7 years from surgery,overall implant survivorship was 98.6%.There were significant postoperative increases in the average Knee Injury and Osteoarthritis Outcome Score for Joint Replacement scores(17.4 at 6 months,26.1 points at two years or more,P<0.001).CONCLUSION The combination of high implant survivorship and substantial improvements in patient-reported outcome measures suggests that the medial dish tibial insert represents a safe and effective option within TKA.Additional investigation is necessary to evaluate the long-term survivorship of this design.展开更多
This study focuses on a 60 V trench MOSFET device designed for operation in space radiation environments.By increasing the bulk region concentration and placing the etched gate trench after the P+implantation process,...This study focuses on a 60 V trench MOSFET device designed for operation in space radiation environments.By increasing the bulk region concentration and placing the etched gate trench after the P+implantation process,we successfully reduced the threshold voltage shift from 6.5 to 2.2 V under a total dose of 400 krad(Si)^(60)Co,allowing the device to operate normally.Structurally,by embedding the source metal in the active and terminal regions,the device demonstrated current degradation without experiencing single-event burnout when subjected to a drain voltage of 60 V and a linear energy transfer value of 75.4 MeV·cm^(2)∕mg from tantalum-ion incidence.TCAD simulations verified that the embedded source metal effectively suppressed parasitic transistor conduction and eliminated the base-region expansion effect,thereby lowering the maximum temperature from 8000 to 1400 K.The irradiation effects of the embedded source metal in the terminal region were also investigated,which can improve the reverse recovery and ensure that the terminal metal does not melt prematurely,thereby significantly enhancing the radiation hardness of the device.展开更多
Integration of renewable energy sources into power systems requires efficient multilevel inverters,capable of producing high-quality output voltage with low total harmonic distortion(THD).Conventional multilevel inver...Integration of renewable energy sources into power systems requires efficient multilevel inverters,capable of producing high-quality output voltage with low total harmonic distortion(THD).Conventional multilevel inverters often suffer from high component count,high switching stress,low voltage gain,and increased cost,limiting their practical application.This paper introduces a high-gain novel topology for multilevel inverters with reduced number of total components per level count,low voltage stress on power conductive devices,and minimizing a cost function,which depends on the number of components,standing voltage on switches and diodes,output voltage levels,and gain.The designed topology,which can be applied in photovoltaic(PV)systems,utilizes only one direct current(DC)input supply and a modular structure with the ability of capacitor’s voltage self-balancing.The high gain property and low THD of the proposed topology are two advantages that provide sine output waveform,with no need to a high DC input voltage source.Moreover,generalized topology,consisting of cascaded basic units,has been proposed.A comprehensive method has been proposed to determining the values of DC supplies in this configuration,aiming to minimize redundant switching modes and maximize the voltage levels count.The comparison with some other multilevel inverters confirms the desired performance of the basic version given inverter.A prototype has been also implemented and the experimental results have been obtained to verify the advantages of the proposed 25-level topology.展开更多
基金Supported by Ningbo NSF(No.2021J234)Zhejiang Provincial Philosophy and Social Sciences Planning Project(No.24NDJC057YB)。
文摘The atom-bond sum-connectivity(ABS)index,put forward by[J.Math.Chem.,2022,60(10):20812093],exhibits a strong link with the acentric factor of octane isomers.The experimental physico-chemical properties of octane isomers,such as boiling point,of formation are found to be better measured by the ABS index than by the Randi,atom-bond connectivity(ABC),and sum-connectivity(SC)indices.One important source of information for researching the molecular structure is the bounds for its topological indices.The extrema of the ABS index of the line,total,and Mycielski graphs are calculated in this work.Moreover,the pertinent extremal graphs were illustrated.
文摘In this study,polyacrylic acid(PAA)films were employed as a model system,and a series of PAA films with tunable water wettability was systematically prepared by varying molecular weight and curing temperature.Using attenuated total reflectance Fourier-transform infrared spectroscopy(ATR-FTIR),the molecular configurations of surface carboxyl groups(COOH),free carboxyl(COOH_(f))and hydrogen-bonded carboxyl(COOH_(HB),were directly correlated with the polar component of surface energy(γ^(s,p)).By decomposing theγ^(s,p)values of the PAA thin films as a sum of the contributions of COOH_(f)and COOH_(H B),the intrinsic polar component of surface energy of COOH_(H B)(γ_(H B)^(s,p*))was quantified for the first time as 8.34 mN/m,significantly lower than that of COOH_(f)(γ_(f)^(s,p*)=34 mN/m).This result highlights that hydrogen bonding markedly reduces theγ^(s,p),providing a rational explanation for the relatively large water contact angle observed on PAA thin films.Furthermore,it establishes a thermodynamic basis for estimating the fraction of surface COOH_(H B)groups(f H B)from wettability measurements.Further extension of the model to carboxyl-terminated self-assembled monolayers(COOH-SAMs)revealed that surface COOH density(ΣCOOH)critically regulates wetting behavior:whenΣCOOH ranges from 4.30 to 5.25 nm^(-2),COOH groups predominantly exist in a free state and facilitate effective hydration layers,thereby promoting superhydrophilicity.Overall,this study not only establishes a unified thermodynamic framework linking surface COOH configurations to macroscopic wettability,but also validates its universality by extending it to COOH-SAMs systems,thereby providing a unified theoretical framework for the controllable design of hydrophilicity in various COOH-functionalized surfaces.
基金funded by the National Council of Science and Technology(postgraduate scholarship awarded to Antonio Gallegos-Islas)the“Antonio Narro”Autonomous Agrarian University.
文摘Pine and oak forests have great relevance worldwide since they are recognized for the benefits and services they provide.Grazing can affect nitrogen reserves in forest trees in complex ways,the effects manifest through changes in the soil,vegetation,and the nitrogen cycle.Nature tourism can have negative impacts on tree physiology.These impacts affect vital processes such as photosynthesis,respiration,water relations,and metabolism.This study was developed in order to determine whether natural populations of pine(Pinus cembroides Zucc.)and oak(Quercus grisea Liebm.)are affected physiologically by grazing and tourism during the stages of development and dormancy,specifically in nitrogenous compounds(Total Soluble Proteins[TSP]and Total Amino Acids[TAA])stocked in perennial organs(stem and roots)and leaves.The results showed that grazing and tourism have both negative and favorable effects on the concentrations of nitrogen compounds.The highest concentration of nitrogenous compounds was found in oak compared to pine.The root,trunk,and leaves in the grazed and non-impacted sites showed the highest concentrations of nitrogen compounds compared to the tourism-impacted site.Pine is the species most affected by anthropogenic processes(grazing and tourism)in the stages of development and dormancy,since the concentrations of nitrogenous compounds were lower compared to oak.
基金supported by the National Natural Science Foundation of China(Nos.82204209 and 82130103)Natural Science Foundation of Henna Province(No.242300421084).
文摘ADPr-ATP is a natural nucleotide with three sugar rings and five pentavalent phosphorus,and can be produced through TIR-catalyzed ADP-ribosylation reactions for plant immunity.Here,we report the first total synthesis of ADPr-ATP(1)with a total yield of 6.4%through 14 steps,featuring late-stage P(V)−N activation reaction of pyrophosphate(4)and 5′-phosphoromorpholidate(25).The protected adenosine 5′-phosphoromorpholidate(24)was prepared on the basis of a scalable to adenosine 5′′-monophosphate(2).The construction of P(V)−N bond in phosphoramidate is esteemed as a critical step as they are sufficiently stable in deprotection reactions.The chemical synthesis of ADPr-ATP can offer an appealing alternative to traditional enzymatic synthesis and fractionation methods.Furthermore,the pRib-AMP and its prodrug are also synthesized to evaluate cytotoxicity and anti-influenza activity in vitro.
基金funded by a Project from China Southern Power Grid Company Ltd.(Nos.ZBKJXM20232481 and ZBKJXM20232482)。
文摘This study investigates the distinct impacts of eastern Pacific(EP)and central Pacific(CP)El Niño events on winter shortwave solar radiation(SSR)in southern China,revealing different spatial distributions and underlying mechanisms.The results show that,during the developing winter of EP El Niño,significant SSR reductions occur in southwestern China and the east coast of southern China due to a strong,zonally extended Northwest Pacific anticyclone that transports moisture from the tropical Northwest Pacific and North Indian Ocean,while the northeast of southern China experiences a weak increase in SSR.In contrast,during the developing winter of CP El Niño,SSR decreases in the east of southern China with a significant decrease in the lower basin of the Yangtze River but an increase in the west of southern China with a remarkable increase in eastern Yunnan.The pronounced east-west dipole pattern in SSR anomalies is driven by a meridionally elongated Northwest Pacific anticyclone,which enhances northward moisture transport to the east of southern China while leaving western areas drier.Further research reveals that distinct moisture anomalies during the developing winter of EP and CP events result in divergent SSR distributions across southern China,primarily through modulating the total cloud cover.These findings highlight the critical need to differentiate between El Niño types when predicting medium and long-term variability of radiation in southern China.
基金supported by the Henan Provincial Medical Science and Technology Research Program,grant funded by the Henan Provincial Health Commission(No.LHGJ 20200888)。
文摘Objective:To investigate the related factors of motility after total hip arthroplasty(THA).Methods:The convenience sampling method was used to include 213 patients receiving THA in our hospital from June 2020 to June 2023.They were divided into 2 groups according to the occurrence of kinesiophobia after THA.The demographic data of the 2 groups were analyzed by single-factor analysis.The factors with statistically significant differences were analyzed by binary logistic regression as independent variables.Finally,Spearman analysis was used to analyze the relationship between risk factors and the degree of kinesiophobia.Results:Among 213 THA patients,38 patients were diagnosed with kinetophobia,and the incidence of kinetophobia was 17.84%.visual analogue scale(VAS)and pain duration before operation were higher in patients with kinetophobia than in patients without kinetophobia.The scores of education level,self-efficacy,and social support were significantly lower than those of the non-phobia group,with statistical significance(P<0.05).Logistic regression analysis showed that VAS was a risk factor for kinetophobia after THA.Education level and self-efficacy were protective factors to reduce the occurrence of kinetophobia after THA(P<0.05).Spearman correlation analysis showed that the degree of pain(r=0.697,P<0.001)was positively correlated with the degree of kinetophobia,while the degree of education(r=-0.647,P<0.001)and self-efficacy(r=-0.756,P<0.001)were negatively correlated with the degree of kinetophobia.Conclusions:The degree of pain is a risk factor of kinesiophobia after THA,and it is positively correlated with the degree.Educational level and self-efficacy were protective factors to reduce the incidence of kinesiophobia and were negatively correlated with the degree of kinesiophobia.
基金Supported by the National Natural Science Foundation of China,No.82402789Beijing Jishuitan Hospital Youcai Plan,No.KYYC202402+1 种基金Beijing Jishuitan Research Funding,No.HL202402and Beijing Natural Science Foundation,No.L232062,No.L222063.
文摘BACKGROUND Aseptic loosening remains the leading cause of revision in primary total hip arthroplasty(pTHA).However,the literature demonstrates significant variability regarding the relative contributions of different factors.AIM To investigate the key determinants of aseptic loosening,we performed a systematic review and meta-analysis.METHODS A comprehensive search of PubMed,Web of Science,EMBASE,and the Cochrane Library was conducted,encompassing studies from database inception to January 1,2025.Meta-analyses were performed to evaluate factors associated with aseptic loosening following pTHA.Inclusion and exclusion criteria were systematically applied at each stage to ensure methodological transparency and reproducibility.Study quality was assessed using standardized categories.Pooled odds ratio(OR)with corresponding 95%confidence interval were calculated with random-or fixed-effects models to generate reliability estimates,and study heterogeneity was visualized using forest plots.Ten factors,categorized into patient-,surgeon-,and device-related domains,were reviewed and meta-analyzed.Funnel plot analysis demonstrated a relatively symmetrical distribution,suggesting minimal publication bias.RESULTS A meta-analysis of 20 studies(520789 participants)found a pooled prevalence of 1.96%.Significant risk factors for aseptic loosening after pTHA included elevated body mass index(OR=1.116,P<0.001),higher Charlson comorbidity index(OR=1.378,P<0.001),prosthesis-related factors(OR=1.497,P<0.001),and adverse lifestyles(OR=2.198,P=0.037).Protective factors were non-white race(OR=0.445,P<0.001)and favorable genetics(OR=0.723,P<0.001).Male sex increased risk(OR=1.232,P=0.016),while age and anatomy were not significant.Surgical expertise showed a slight protective effect(OR=1.048,P<0.001).A comprehensive understanding of the modifiable and non-modifiable factors contributing to aseptic loosening after pTHA requires consideration of patient-related factors,surgical expertise,and prosthesis characteristics.CONCLUSION The identification of these factors is critical for risk mitigation.High-risk patients should receive targeted counseling regarding individualized profiles.Further studies are warranted to establish clearer causal relationships and identify additional contributing factors.
基金supported by the National Natural Science Foundation of China(Nos.42371139,42201152)the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(No.CUG240629)+2 种基金the“CUG Scholar”Scientific Research Funds at China University of Geosciences(Wuhan)(No.2023092)the Gansu Province Natural Science Foundation Key Project(No.23JRRA858)CAS President's International Fellowship for Visiting Scientists(No.2024PVC003)。
文摘The carbon cycle stands as a cornerstone among the Earth's material cycles,carrying profound implications for global climate dynamics and humanity's sustenance and advancement.Additionally,nitrogen,as a vital nutrient element,plays a pivotal role in biogeochemical processes,exerting significant influence on the ecological environment within watersheds.In this study,an analysis of the carbon(C)and nitrogen(N)components in the river water of 12 alpine basins on the eastern margin of the Tibetan Plateau(TP)reveals that the average dissolved organic carbon(DOC)concentration in the river water is 0.76±0.67 mg/L,indicating a lower level compared to the global river average organic carbon content.Specifically,the average DOC concentrations were 0.42±0.22 and 1.56±0.68 mg/L in the glacial and non-glacial basins,respectively.The average dissolved inorganic carbon(DIC)concentration in the eastern TP is 27.04±20.19 mg/L,with the lowest DIC observed at Dagu Glacier and the highest at Daxia River.Furthermore,the average dissolved total carbon(DTC)concentration in glacier river water was 18.87±12.65 mg/L,contrasting with 48.23±21.07 mg/L in non-glacial basins.The mean concentration of total nitrogen(TN)in the eastern TP averaged 0.97±0.54 mg/L,with the glacial basin registering 1.01±0.47 mg/L and the non-glacial basin at 0.89±0.70 mg/L.Evaluating the release fluxes of carbon and nitrogen across 12 river basins revealed a range of DTC emission fluxes from 0.32×10^(9)to 31.02×10^(9)g·C/a,with inorganic carbon comprising 71.0%to 99.5%.Consequently,the carbon emission flux for seven glacier basins totaled 15.91×10^(9)g·C/a,while for the five non-glacial river basins,it reached 87.37×10^(9)g·C/a.The total TN release fluxes across 12 small river basins amounted to 2.46×10^(9)g·N/a,with 0.84×10^(9)g·N/a released in glacial basins and 1.62×10^(9)g·N/a in the nonglacial basin.This study elucidates the spatial distribution and transport mechanisms of carbon and nitrogen elements within the glacial and downstream non-glacial basins,offering valuable insights into the biogeochemical cycles of carbon and nitrogen in the eastern Tibetan Plateau.
基金supported by the National Natural Science Foundation of China(No.12301672)the Shanghai Science and Technology Innovation Action Plan(Yangfan Special Project),China(No.23YF1401300)。
文摘The micro-riblet structures have been demonstrated effective in controlling the Total Pressure Loss(TPL)of aero-engine blades.However,due to the considerable scale gap between micro-texture and an actual aero-engine blade,wind tunnel tests and numerical simulations with massive grids directly describing the global flow field are costly for aerodynamic evaluation.Furthermore,the fine micro surface structure brings unavoidable manufacturing errors,and the probability prediction contributes to gaining the confidence interval of the results.Therefore,a novel relay-based probabilistic model for multi-fidelity scenarios in the TPL prediction of a compressor cascade with micro-riblet surfaces is proposed to trade off accuracy and efficiency.Combined with the low-fidelity flow data generated by an aerodynamic solution strategy using the boundary surrogate model and the high-fidelity flow data from the experiment,the relay-based modeling has been achieved through knowledge transferring,and the confidence interval can be provided by the Gaussian Process Regression(GPR)model.The TPL of compressor cascades with micro-riblet surfaces under different surface structures at March number Ma=0.64,0.74,0.84 have been evaluated using the Relay-Based Probabilistic(RBP)model.The results illustrate that the RBP model could provide higher accuracy than the Single-Fidelity-Data-Driven(SFDD)prediction model,which show the promising potential of multi-fidelity scenarios data fusion in the aerodynamic evaluation of multi-scale configurations.
文摘BACKGROUND Salvage of the infected long stem revision total knee arthroplasty is challenging due to the presence of well-fixed ingrown or cemented stems.Reconstructive options are limited.Above knee amputation(AKA)is often recommended.We present a surgical technique that was successfully used on four such patients to convert them to a knee fusion(KF)using a cephalomedullary nail.CASE SUMMARY Four patients with infected long stem revision knee replacements that refused AKA had a single stage removal of their infected revision total knee followed by a KF.They were all treated with a statically locked antegrade cephalomedullary fusion nail,augmented with antibiotic impregnated bone cement.All patients had successful limb salvage and were ambulatory with assistive devices at the time of last follow-up.All were infection free at an average follow-up of 25.5 months(range 16-31).CONCLUSION Single stage cephalomedullary nailing can result in a successful KF in patients with infected long stem revision total knees.
文摘Objective:To systematically summarize and evaluate the evidence on discharge preparation services for patients undergoing total knee arthroplasty,providing an evidence-based foundation for developing scientific and standardized discharge preparation intervention programs in clinical practice.Methods:Following the“5S”evidence model,literature such as guidelines,expert consensuses,evidence summaries and randomized controlled trials related to discharge preparation services for total knee arthroplasty patients were retrieved from relevant websites and databases,both domestic and international,from database inception to August 31,2025.Two researchers independently screened the literature,conducted quality appraisals,and extracted and synthesized the evidence.Results:A total of 15 articles were included,comprising 3 guidelines,4 expert consensuses,3 evidence summaries,3 systematic reviews and 2 randomized controlled trials.Ultimately,23 pieces of evidence were summarized across five aspects.Conclusion:This study synthesizes the evidence on discharge preparation services for patients undergoing total knee arthroplasty.It is recommended that healthcare professionals apply this evidence in clinical practice,considering specific circumstances and patient needs.
文摘Leg-length discrepancy(LLD)in individuals experiencing total hip arthroplasty(THA)is related to a substantially higher fall risk,length of post-operative hospital in-patient stay,elevated implant-related adverse events,and earlier revision.Therefore,it is essential to try to avoid LLD when implanting a THA.Several studies focus on this issue,including the following:Accelerometer-based portable navigation system,preoperative digital templating,robot-assisted surgery,the anatomical marker positioning method(shoulder-to-shoulder)and the artificial intelligence-based three-dimensional planning software system.The aforementioned methods should be familiar to surgeons who perform THA procedures,as a fundamental objective of this surgical intervention is to avoid LLD.
基金the National Natural Science Foundation of China(No.22325106)the start-up funding from Wuhan University for financial support.We thank Prof.
文摘The significant medicinal values associated with C19-hydroxylated steroids dictate a growing demand for new synthetic strategies that would provide facile access to these challenging targets.This review will encapsulate the key synthetic strategies for C19-hydroxylated steroids,which include indirect C–H oxidation and direct C–H oxidation in semi-synthesis as well as total synthesis.
文摘Foreign Trade Posts Strong Growth China’s foreign trade has posted a robust start to the year,with the total value of trade in goods surging 18.3 percent year on year in the January–February period,latest official data showed.Data released on 10 March by the General Administration of Customs revealed that total goods trade value had reached 7.73 trillion yuan(about$1.12 trillion)during this period.
基金Project supported by the National Natural Science Foundation of China(Grant No.11872033)the Beijing Natural Science Foundation,China(Grant No.3172017)。
文摘This study investigates the mechanisms of friction-induced vibration under periodic variations in stress distribution using an improved fretting friction model.A fretting friction test system integrated with a total reflection method was developed to analyze interfacial contact behavior under dynamic loading conditions.An improved fretting friction model was established,incorporating three critical nonlinear parameters:the hysteretic friction coefficient,tangential stiffness fluctuations,and stress distribution.Through systematic validation,the model demonstrates high-fidelity replication of experimental steady-state amplitude-frequency responses.Key findings reveal that non-uniform stress distribution governs irregularities in the vibration response,and increased uniformity intensifies stick-slip instabilities.Near the stick-slip transition threshold,distinct vibration anomalies emerge due to the coupled effects of stress heterogeneity,friction hysteresis,and stiffness variations during state transitions.Furthermore,the magnitude of the normal contact force systematically alters the dominant interfacial contact mechanism.The different interfacial contact states at various frequencies lead to distinct steady-state responses.This shift elevates resonance frequencies and amplifies higher-order resonant peaks.The fretting friction model provides a predictive framework for vibration control under dynamic interfacial loading.
文摘BACKGROUND The optimal surgical approach for patients with primary glenohumeral osteoarthritis(GHOA)and an intact rotator cuff remains debated.While anatomic total shoulder arthroplasty(TSA)has traditionally been favoured,reverse TSA(RTSA)is increasingly utilized.AIM To systematically compare the outcomes of RTSA and TSA in this specific patient population.METHODS A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines.Retrospective comparative studies evaluating RTSA and TSA in patients with GHOA and intact rotator cuff were included.Key outcomes assessed included complication and reoperation rates,patient-reported outcome measures(PROMs),and range of motion.Risk of bias was assessed using the Risk of Bias in Non-randomized Studies of Interventions tool.RESULTS Twelve studies encompassing 1608 patients(580 RTSA,1028 TSA)met inclusion criteria.RTSA was associated with a lower reoperation rate compared to TSA[odds ratio=0.37;95%confidence interval(CI):0.14-0.94;P value=0.04],while no significant difference in overall complication rates was observed(odds ratio=0.47;95%CI:0.19-1.16;P value=0.10).RTSA patients showed superior outcomes in University of California Los Angeles,Simple Shoulder Test,and Shoulder Pain and Disability Index scores;however,the differences did not exceed the minimal clinically important difference.TSA patients had significantly better external rotation(mean difference=-9.0°;95%CI:-13.21 to-5.02;P value<0.0001).No significant differences were found in other range of motion measures or satisfaction scores.The overall methodological quality of included studies was moderate to serious.CONCLUSION In patients with GHOA and an intact rotator cuff,RTSA may offer comparable or improved outcomes to TSA with lower reoperation rates and similar complication profiles.Functional outcomes favour RTSA in certain patientreported outcome measures,while TSA retains an advantage in external rotation.Surgical decision-making should remain individualized based on patient characteristics and functional demands.
基金Supported by National Natural Science Foundation of Guangdong,China(No.2020A1515010829,No.2023A1515011652,No.2025A1515012389)Science and Technology Program of Guangzhou,China(No.2025A03J4033).
文摘AIM:To evaluate the agreement of axial length(AL),anterior chamber parameters,and total cornea power obtained by swept-source optical coherence tomography(SS-OCT)-based and Scheimpflug-based optical biometers in myopic children.METHODS:AL,steep keratometry(K),flat K,posterior corneal keratometry(PK),total keratometry(TK),anterior chamber depth(ACD),horizontal corneal diameter(CD),and central corneal thickness(CCT)were obtained using IOL Master 700 and Pentacam AXL.The agreement between the devices was evaluated using intraclass correlation coefficients(ICC),Bland-Altman plots,and astigmatism vector analysis.RESULTS:Totally 175 myopic children(48.5%male)with a mean age of 10.29±2.14y were enrolled.The ICC and Bland-Altman plots indicated a satisfactory agreement for AL,ACD,and CCT.The mean difference in CD of-0.31±0.30 mm was considered clinically significant(>0.2 mm).Additionally,measurements of K and TK obtained from the IOL Master 700 showed good agreement.Nevertheless,there were clinically significant differences observed in PK,simulated keratometry(simK),total cornea power,and astigmatism(at least 10%of the cases with a difference of>10 degrees in meridian)between the two devices.CONCLUSION:The study findings demonstrate a significant difference in K,PK,astigmatism,and CD,indicating that the two optical biometers cannot be considered interchangeable.Therefore,it is recommended to utilize one kind device for follow-up examinations in myopic children.
文摘BACKGROUND Medial dished(MD)liner designs for cruciate-retaining(CR)total knee arthroplasty(TKA)are a relatively novel development.MD tibial inserts have a more constraining medial side,which allows for more similar kinematics and function to a native knee.AIM To evaluate the clinical results and patient-reported outcomes after CR TKA procedures utilizing a kinematically designed medial dish system.METHODS A multicenter,retrospective cohort review of 139 primary elective TKAs utilizing a kinematically designed CR Knee System(JOURNEY™II CR MD;Smith and Nephew,Memphis,TN,United States)at three different institutions with a minimum of two years of follow-up.Demographic information,clinical outcomes,and patient-reported outcome measures were collected and analyzed.RESULTS With up to 3.7 years from surgery,overall implant survivorship was 98.6%.There were significant postoperative increases in the average Knee Injury and Osteoarthritis Outcome Score for Joint Replacement scores(17.4 at 6 months,26.1 points at two years or more,P<0.001).CONCLUSION The combination of high implant survivorship and substantial improvements in patient-reported outcome measures suggests that the medial dish tibial insert represents a safe and effective option within TKA.Additional investigation is necessary to evaluate the long-term survivorship of this design.
基金supported in part by National R&D Program for Major Research Instruments of China(No.62027814)。
文摘This study focuses on a 60 V trench MOSFET device designed for operation in space radiation environments.By increasing the bulk region concentration and placing the etched gate trench after the P+implantation process,we successfully reduced the threshold voltage shift from 6.5 to 2.2 V under a total dose of 400 krad(Si)^(60)Co,allowing the device to operate normally.Structurally,by embedding the source metal in the active and terminal regions,the device demonstrated current degradation without experiencing single-event burnout when subjected to a drain voltage of 60 V and a linear energy transfer value of 75.4 MeV·cm^(2)∕mg from tantalum-ion incidence.TCAD simulations verified that the embedded source metal effectively suppressed parasitic transistor conduction and eliminated the base-region expansion effect,thereby lowering the maximum temperature from 8000 to 1400 K.The irradiation effects of the embedded source metal in the terminal region were also investigated,which can improve the reverse recovery and ensure that the terminal metal does not melt prematurely,thereby significantly enhancing the radiation hardness of the device.
文摘Integration of renewable energy sources into power systems requires efficient multilevel inverters,capable of producing high-quality output voltage with low total harmonic distortion(THD).Conventional multilevel inverters often suffer from high component count,high switching stress,low voltage gain,and increased cost,limiting their practical application.This paper introduces a high-gain novel topology for multilevel inverters with reduced number of total components per level count,low voltage stress on power conductive devices,and minimizing a cost function,which depends on the number of components,standing voltage on switches and diodes,output voltage levels,and gain.The designed topology,which can be applied in photovoltaic(PV)systems,utilizes only one direct current(DC)input supply and a modular structure with the ability of capacitor’s voltage self-balancing.The high gain property and low THD of the proposed topology are two advantages that provide sine output waveform,with no need to a high DC input voltage source.Moreover,generalized topology,consisting of cascaded basic units,has been proposed.A comprehensive method has been proposed to determining the values of DC supplies in this configuration,aiming to minimize redundant switching modes and maximize the voltage levels count.The comparison with some other multilevel inverters confirms the desired performance of the basic version given inverter.A prototype has been also implemented and the experimental results have been obtained to verify the advantages of the proposed 25-level topology.
