We demonstrate a high power,widely tunable femtosecond MgO-doped periodically poled lithium niobate(MgO:PPLN)optical parametric oscillator(OPO)at 151 MHz,pumped by a Kerr-lens mode-locked Yb:KGW laser.With a maximum p...We demonstrate a high power,widely tunable femtosecond MgO-doped periodically poled lithium niobate(MgO:PPLN)optical parametric oscillator(OPO)at 151 MHz,pumped by a Kerr-lens mode-locked Yb:KGW laser.With a maximum pump power of 7 W,the OPO is capable of delivering as high as 2.2 W of the signal centered around 1500 nm with tunable signal spectrum ranges of 1377 nm-1730 nm at an extraction efficiency of 31.4%,which exhibits a long-term passive power stability better than 0.71%rms over 4 h.The maximum idler bandwidths of 185 nm at 3613 nm are obtained across the idler tuning ranges of 2539 nm-4191 nm.By compensating intracavity dispersion,the signal has the shortest pulse duration of 170 fs at 1428 nm.展开更多
A direct Kerr-lens mode-locked Tm:LuYO_(3)ceramic laser without the aid of any mode-locked starting element is reported for the first time. A pulse duration as short as 259 fs and a maximum average output power of 326...A direct Kerr-lens mode-locked Tm:LuYO_(3)ceramic laser without the aid of any mode-locked starting element is reported for the first time. A pulse duration as short as 259 fs and a maximum average output power of 326 m W are obtained at a repetition rate of 97.1 MHz. The corresponding optical spectrum centered at 2053 nm exhibits a bandwidth of 19.8 nm,which indicates the presence of nearly Fourier transform-limited pulses. Such a Kerr-lens mode-locked Tm:LuYO_(3)ceramic laser is a promising ultrashort pulse source, with both the excellent laser characteristics of Tm:LuYO3and the high-power 790 nm laser diode pumping scheme.展开更多
In recent years,peanut yield and quality are more seriously affected by pod rot disease in China.However,managing this disease has proven challenging due to the wide host range of its pathogens.In this study,four soil...In recent years,peanut yield and quality are more seriously affected by pod rot disease in China.However,managing this disease has proven challenging due to the wide host range of its pathogens.In this study,four soil samples were collected from fields with pod rot disease in Hebei Province,and 454 pyrosequencing was used to analyze the fungal communities structure within them.All 38490 ITS high-quality sequences were grouped into 1203 operational taxonomic units,the fungal community diversity of four soil samples was evaluated and compared using Shannon index and Simpson index.The results showed that members of Ascomycota were dominant,followed by Basidiomycota.According to the BLAST results at the species level,Guehomyces had the highest abundance,accounting for about 7.27%,followed by Alternaria,Fusarium,and Davidiella.The relative abundance of Fusarium oxysporum isolated from rotting peanuts in soil with peanut rot was higher than that in the control,indicating that Fusarium oxysporum might be one of the main pathogenic fungus of peanut rot in this area.This study delved into the broader fungal community associated with peanut pod rot,providing a theoretical foundation for preventing and treating this disease in agriculture.展开更多
The droplet size, size distribution, refractive index, and temperature can be measured simultaneously by the rainbow technique. In the present work, the rainbow scattering diagram for a spherical droplet in the second...The droplet size, size distribution, refractive index, and temperature can be measured simultaneously by the rainbow technique. In the present work, the rainbow scattering diagram for a spherical droplet in the secondary rainbow region is simulated by the use of the generalized Lorenz-Mie theory. For achieving high spatial resolution in denser droplet sprays, a focused Gaussian beam is used. For droplet characterization, different inversion algorithms are investigated, which includes trough-trough (<em>θ</em><sub>min1</sub> and <em>θ</em><sub>min2</sub>) method and inflection-inflection (<em>θ</em><sub>inf1</sub> and <em>θ</em><sub>inf2</sub>) method. For the trough-trough algorithm, the absolute error of the refractive index is between −6.4 × 10<sup>−4</sup> and 1.7 × 10<sup>−4</sup>, and the error of the droplet radius is only between −0.55% and 1.77%. For the inflection-inflection algorithm, the maximum absolute error of the inverted refractive index is less than −1.1 × 10<sup>−3</sup>. The error of the droplet radius is between −0.75% and 5.67%.展开更多
China’s recently announced directive on tackling climate change,namely,to reach carbon peak by 2030 and to achieve carbon neutrality by 2060,has led to an unprecedented nationwide response among the academia and indu...China’s recently announced directive on tackling climate change,namely,to reach carbon peak by 2030 and to achieve carbon neutrality by 2060,has led to an unprecedented nationwide response among the academia and industry.Under such a directive,a rapid increase in the grid penetration rate of solar in the near future can be fully anticipated.Although solar radiation is an atmospheric process,its utilization,as to produce electricity,has hitherto been handled by engineers.In that,it is thought important to bridge the two fields,atmospheric sciences and solar engineering,for the common good of carbon neutrality.In thisüberreview,all major aspects pertaining to solar resource assessment and forecasting are discussed in brief.Given the size of the topic at hand,instead of presenting technical details,which would be overly lengthy and repetitive,the overarching goal of this review is to comprehensively compile a catalog of some recent,and some not so recent,review papers,so that the interested readers can explore the details on their own.展开更多
The film contained L-cysteine and gold nanoparticles were provided by self-assembled monolayers (SAMs) and potentiostatic electrodeposition technology on the gold electrode. Two methods were used to study the film: In...The film contained L-cysteine and gold nanoparticles were provided by self-assembled monolayers (SAMs) and potentiostatic electrodeposition technology on the gold electrode. Two methods were used to study the film: In the first, cyclic voltammetry (CV) was used to inspect the functional groups of the film and the same time hydroquinone was chosen to be a probe molecule in the based solution;secondly, based on analytical technology of scanning electrochemical microscopy (SECM), the heterogeneous rate constant (keff) between solid phase (the modified electrode) and liquid phase (K3Fe(CN)6) was obtained. As a result, the better binary catalysis of hydroquinone was demonstrated and the heterogeneous rate constant (keff) is the greater at 8 h for L-cysteine self-assembled monolayers (SAMs).展开更多
The posterior rootlets in L6 and S1 spinal cord of adult male Sprague-Dawley rats underwent electrostimulation. The bladder pressure, urethral perfusion pressure and intracavernous pressure were recorded. When some po...The posterior rootlets in L6 and S1 spinal cord of adult male Sprague-Dawley rats underwent electrostimulation. The bladder pressure, urethral perfusion pressure and intracavernous pressure were recorded. When some posterior rootlets of L6 and Sl were electrostimulated, the intracavernous pressure peaked rapidly, but the bladder pressure and the urethral perfusion pressure curve did not show great change. When other rootlets were stimulated, the bladder pressure changed greatly, but the urethral perfusion pressure and the intracavernous pressure did not show great change. When different rootlets were stimulated, the urethral perfusion pressure changed maximally, but there were no great changes in bladder pressure or intracavernous pressure. Furthermore, stimulation of some rootlets produced simultaneous changes in two or three different pressure measures mentioned above. The results demonstrate that regulation by L6 and S1 posterior rootlets of the rat bladder detrusor, external urethral sphincter and penis cavernous body are significantly distinct. Different rootlets can be distinguished by electrostimulation.展开更多
Recently,deep learning(DL)has been widely used in the field of remaining useful life(RUL)prediction.Among various DL technologies,recurrent neural network(RNN)and its variant,e.g.,long short-term memory(LSTM)network,h...Recently,deep learning(DL)has been widely used in the field of remaining useful life(RUL)prediction.Among various DL technologies,recurrent neural network(RNN)and its variant,e.g.,long short-term memory(LSTM)network,have gained extensive attention for their ability to capture temporal dependence.Although existing RNN-based methods have demonstrated their RUL prediction effectiveness,they still suffer from the following two limitations:1)it is difficult for the RNN to directly extract degradation features from original monitoring data and 2)most RNN-based prognostics methods are unable to quantify RUL uncertainty.To address the aforementioned limitations,this paper proposes a new prognostics method named residual convolution LSTM(RC-LSTM)network.In the RC-LSTM,a new ResNet-based convolution LSTM(Res-ConvLSTM)layer is stacked with a convolution LSTM(ConvLSTM)layer to extract degradation representations from monitoring data.Then,under the assumption that the RUL follows a normal distribution,an appropriate output layer is constructed to quantify the uncertainty of prediction results.Finally,the effectiveness and superiority of the RC-LSTM are verified using monitoring data from accelerated bearing degradation tests.展开更多
Soybean(Glycine max[L.]Merr.)is a food and oil crop whose growth and yield are influenced by root and nodule development.In the present study,Gm NMHC5 was found to promote the formation of nodules in overexpressing mu...Soybean(Glycine max[L.]Merr.)is a food and oil crop whose growth and yield are influenced by root and nodule development.In the present study,Gm NMHC5 was found to promote the formation of nodules in overexpressing mutants.In contrast,the number of nodules in Gmnmhc5 edited with CRISPR/Cas9 decreased sharply.In 35 S:Gm NMHC5 mutants,expression levels of genes involved in nodulation were significantly up-regulated.Both in vitro and in vivo biochemical analyses showed that Gm NMHC5 directly interacted with Gm GAI(a DELLA protein),and the content of gibberellin 3(GA_(3))in overexpressing mutants was lower than that in the wild type.These results revealed that Gm NMHC5 participates in the classical GA signaling pathway,and may regulate the content of GA_3 to match the optimal concentration required for nodule formation,thereby promoting nodulation by directly interacting with Gm GAI.A model illustrating the mechanism by which Gm NMHC5 promotes soybean nodulation is presented.展开更多
BACKGROUND: Studies have demonstrated that selective innervation of the sacral nerve tract to the bladder plays an important role in bladder functional reconstruction following spinal cord injury. However, there are ...BACKGROUND: Studies have demonstrated that selective innervation of the sacral nerve tract to the bladder plays an important role in bladder functional reconstruction following spinal cord injury. However, there are very few studies reporting detailed morphological characteristics of urogenital center and lumbosacral nerve roots. OBJECTIVE: To analyze the spinal cord segment of the lumbosacral spinal cord urogenital center, and to observe morphological characteristics. DESIGN, TIME AND SETTING: A neuroanatomical study was performed at the Laboratory of Neuroanatomy, Peking University Health Science Center between September 2007 and March 2008. MATERIALS: Horseradish peroxidase-conjugated cholera toxin B subunit (CB-HRP) was purchased from Sigma, USA; surgical microscope was purchased from Zhenjian Zhongtian Optical Instrument, Jiangsu Province, China; BCL-420 biological and functional experimental system was purchased from Taimeng Science and Technology, Sichuan Province, China. METHODS: A total of 36 adult, Sprague Dawley rats were randomly assigned to groups A (n = 10), B (n = 10), C (n = 10), and D (n = 6). CB-HRP (3%, 10-15 μL) was injected into the bladder detrusor muscle (group A), external urethral sphincter (group B), and perineal muscles (group C), respectively. Rats in group D were not given any treatments. MAIN OUTCOME MEASURES: At 72 hours after CB-HRP injection, CB-HRP-positive neurons were analyzed in lumbosacral segments using 3, 3', 5, 5'-tetramethylbenzidine staining and an Olympus optic microscope, while anatomical structures in the respective spinal nerve tract were observed using a surgical microscope. RESULTS: CB-HRP-positive neurons were distributed in the L6-S1 segments of the spinal cord, and neurons primarily innervating the bladder detrusor muscle were located at the sacral parasympathetic nucleus and the intermediolateral nucleus. In addition, neurons that primarily innervate the external urethral sphincter and perineal muscles were observed in the ventrolateral portion (Onuf's nucleus). The lumbar-sacral nerve roots were composed of varying nerve tracts, Le., they were typically divided into 1-2 sub-bundles, and the sub-bundles were then divided into 2-3 tiny bundles. There were extensive fibro-connections between the rootlets. CONCLUSION: The urogenital center in Sprague Dawley rats was located in the L6 -S1 segments of the spinal cord, and the rootlets were clearly observed. Therefore, this rat experimental model could be utilized for highly selective anterior/posterior rhizotomy.展开更多
We study the relation between halo concentration and mass(c-M relation) using galaxy catalogs of the Seventh and Eighth Data Releases of the Sloan Digital Sky Survey(SDSS DR7 and DR8). Assuming that the satellite gala...We study the relation between halo concentration and mass(c-M relation) using galaxy catalogs of the Seventh and Eighth Data Releases of the Sloan Digital Sky Survey(SDSS DR7 and DR8). Assuming that the satellite galaxies follow the distribution of dark matter, we derive the halo concentration by fitting the satellite radial profile with a Nararro Frank and White(NFW) format. The derived c-M relation covers a wide halo mass range from10^(11.6)to 10^(14.1)M_(⊙). We confirm the anti-correlation between the halo mass and concentration as predicted in cosmological simulations. Our results are in good agreement with those derived using galaxy dynamics and gravitational lensing for halos of 10^(11.6)– 10^(12.9)M_(⊙), while they are slightly lower for halos of 10^(12.9)– 10^(14.1)M_(⊙).This is because blue satellite galaxies are less concentrated, especially in the inner regions. Instead of using all satellite galaxies, red satellites could be better tracers of the underlying dark matter distribution in galaxy groups.展开更多
This paper presents an effective and feasible method for detecting dynamic load-altering attacks(D-LAAs)in a smart grid.First,a smart grid discrete system model is established in view of D-LAAs.Second,an adaptive fadi...This paper presents an effective and feasible method for detecting dynamic load-altering attacks(D-LAAs)in a smart grid.First,a smart grid discrete system model is established in view of D-LAAs.Second,an adaptive fading Kalman filter(AFKF)is designed for estimating the state of the smart grid.The AFKF can completely filter out the Gaussian noise of the power system,and obtain a more accurate state change curve(including consideration of the attack).A Euclidean distance ratio detection algorithm based on the AFKF is proposed for detecting D-LAAs.Amplifying imperceptible D-LAAs through the new Euclidean distance ratio improves the D-LAA detection sensitivity,especially for very weak D-LAA attacks.Finally,the feasibility and effectiveness of the Euclidean distance ratio detection algorithm are verified based on simulations.展开更多
Wound field switched flux(WFSF)machines exhibits characteristics of the simple robust rotor,flexible flux-adjustable capability,and no risk of demagnetization.However,they suffer from a poor torque density compared wi...Wound field switched flux(WFSF)machines exhibits characteristics of the simple robust rotor,flexible flux-adjustable capability,and no risk of demagnetization.However,they suffer from a poor torque density compared with permanent magnet machines due to the saturation.Therefore,in this paper,two WFSF machines with single-and double-layer DC windings,respectively,are optimized for the maximum torque.The end-winding(EW)lengths differ in these two machines,which can affect the optimal design.Design parameters including the DC to armature winding copper loss ratio,slot area ratio and split ratio are optimized when two machines have the same copper loss and overall sizes.In addition,the influence of the flux density ratio,total copper loss,air-gap length and aspect ratio on the optimal split ratio is investigated using the finite element method and results are explained through the analytical model accounting for the saturation.It is discovered that the EWs have no effect on the optimal copper loss ratio,which is unity.In terms of the slot area ratio,the machine with single-layer DC windings prefers smaller DC slot areas than armature slot areas.In the WFSF machine with longer EWs,the optimal split ratio becomes smaller.Moreover,compared with other parameters,the flux density ratio can significantly affect the optimal split ratio.展开更多
Introduction:Observational studies have revealed an association between waist circumference(WC)and atrial fibrillation(AF).However,it is difficult to infer a causal relationship from observational studies because the ...Introduction:Observational studies have revealed an association between waist circumference(WC)and atrial fibrillation(AF).However,it is difficult to infer a causal relationship from observational studies because the observed associations could be confounded by unknown risk factors.Therefore,the causal role of WC in AF is unclear.This study was designed to investigate the causal association between WC and AF using a two-sample Mendelian randomization(MR)analysis.Methods:In our two-sample MR analysis,the genetic variation used as an instrumental variable for MR was acquired from a genome-wide association study(GWAS)of WC(42 single nucleotide polymorphisms with a genetic significance of P<5×10^(-8)).The data of WC(from the Genetic Investigation of ANthropometric Traits consortium,containing 232,101 participants)and the data of AF(from the European Bioinformatics Institute database,containing 55,114 AF cases and 482,295 controls)were used to assess the causal role of WC on AF.Three different approaches(inverse variance weighted[IVW],MR-Egger,and weighted median regression)were used to ensure that our results more reliable.Results:All three MR analyses provided evidence of a positive causal association between high WC and AF.High WC was suggested to increase the risk of AF based on the IVW method(odds ratio[OR]=1.43,95%confidence interval[CI],1.30-1.58,P=2.51×10^(-13)).The results of MR-Egger and weighted median regression exhibited similar trends(MR-Egger OR=1.40[95%CI,1.08-1.81],P=1.61×10^(-2);weighted median OR=1.39[95%CI,1.21-1.61],P=1.62×10^(-6)).MR-Egger intercepts and funnel plots showed no directional pleiotropic effects between high WC and AF.Conclusions:Our findings suggest that greater WC is associated with an increased risk of AF.Taking measures to reduce WC may help prevent the occurrence of AF.展开更多
The oxidation behavior and kinetics of Ti_(2)AlC-20vol.%TiB_(2) composite at 600-900℃ in air were investigated.The results showed that the oxidation kinetics of the composite followed a logarithmic law within the giv...The oxidation behavior and kinetics of Ti_(2)AlC-20vol.%TiB_(2) composite at 600-900℃ in air were investigated.The results showed that the oxidation kinetics of the composite followed a logarithmic law within the given temperature range,which indicated that the composites had excellent oxidation resistance.The selective oxidation of Al in Ti_(2)AlC was greatly enhanced,which facilitated the formation of a continuous and dense protective layer of Al_(2)O_(3).Meanwhile,the existence of molten B_(2)O_(3) inhibited the outward diffusion of Ti and inward diffusion of oxygen,which prevented the growth of anatase TiO_(2) at 600℃ and rutile TiO_(2) at 700-900℃.Therefore,the incorporation of TiB_(2) completely inhibited the abnormally rapid oxidation of bulk Ti_(2)AlC at 600℃ and improved its oxidation resistance at 700-900℃.展开更多
Frequency microcombs with microwave and millimeter-wave repetition rates provide a compact solution for coherent communication and information processing.The implementation of these microcombs using a CMOS-compatible ...Frequency microcombs with microwave and millimeter-wave repetition rates provide a compact solution for coherent communication and information processing.The implementation of these microcombs using a CMOS-compatible platform further paves the way for large-scale photonic integration and modularity.Here,we demonstrate free-running soliton microcombs with K-band repetition rates with very low phase noise over a 4 GHz pump detuning range reaching−117(−123)dBc/Hz at 10 kHz offset for a 19.7(10)GHz carrier without active pump stabilization,exceeding commercial electronic microwave oscillators at frequency offsets above 40 kHz.The minimum laser noise to soliton microwave signal transduction factor observed is−73dB.This noise performance is achieved using a hybridized dual-mode for soliton generation to achieve passive thermal stabilization and minimal soliton spectrum shift from prior Raman scattering and dispersive wave formation.We further examine the locking of the repetition rate to an external ultrastable photonic oscillator to illustrate the feasibility of phase noise suppression below the thermorefractive noise limits of microresonator frequency combs.展开更多
Vascular complications of diabetes pose a severe threat to human health.Prevention and treatment protocols based on a single vascular complication are no longer suitable for the long-term management of patients with d...Vascular complications of diabetes pose a severe threat to human health.Prevention and treatment protocols based on a single vascular complication are no longer suitable for the long-term management of patients with diabetes.Diabetic panvascular disease(DPD)is a clinical syndrome in which vessels of various sizes,including macrovessels and microvessels in the cardiac,cerebral,renal,ophthalmic,and peripheral systems of patients with diabetes,develop atherosclerosis as a common pathology.Pathological manifestations of DPDs usually manifest macrovascular atherosclerosis,as well as microvascular endothelial function impairment,basement membrane thickening,and microthrombosis.Cardiac,cerebral,and peripheral microangiopathy coexist with microangiopathy,while renal and retinal are predominantly microangiopathic.The following associations exist between DPDs:numerous similar molecular mechanisms,and risk-predictive relationships between diseases.Aggressive glycemic control combined with early comprehensive vascular intervention is the key to prevention and treatment.In addition to the widely recommended metformin,glucagon-like peptide-1 agonist,and sodium-glucose cotransporter-2 inhibitors,for the latest molecular mechanisms,aldose reductase inhibitors,peroxisome proliferator-activated receptor-γagonizts,glucokinases agonizts,mitochondrial energy modulators,etc.are under active development.DPDs are proposed for patients to obtain more systematic clinical care requires a comprehensive diabetes care center focusing on panvascular diseases.This would leverage the advantages of a cross-disciplinary approach to achieve better integration of the pathogenesis and therapeutic evidence.Such a strategy would confer more clinical benefits to patients and promote the comprehensive development of DPD as a discipline.展开更多
Northeast China(NEC)is one of the vital commercial grain bases in China and it has suffered from soil erosion due to prolonged cultivation and lack of protection.To determine long-term trends of precipi-tation and rai...Northeast China(NEC)is one of the vital commercial grain bases in China and it has suffered from soil erosion due to prolonged cultivation and lack of protection.To determine long-term trends of precipi-tation and rainfall erosivity over NEC during the latest decades,daily precipitation for the entire year during 1961-2020 and hourly precipitation for the warm season(May to September)during 1971-2020 were collected for 192 and 126 stations,respectively.Three seasons,including the cold season(October to April),early warm season(May to June),and late warm season(July to September)were divided according to the combination of precipitation and vegetation.Results demonstrate:(1)Daily precipita-tion reveals total precipitation and rainfall erosivity in the cold season and early warm season increase significantly at relative rates of 3.1%-6.1%compared with the average during 1961-2020,and those in the late warm season decrease insignificantly.(2)Hourly precipitation reveals storms occurring in the early and late warm seasons have undergone significant increasing changes,which shift towards longer storm duration,larger amount,peak intensity,kinetic energy,and rainfall erosivity during 1971-2020.Moreover,the frequency of extreme storms increased.(3)Rainfall erosivities estimated from daily pre-cipitation during 1971-2020 increase insignificantly for the early and late warm season,whereas those from hourly precipitation increase significantly(6.1%and 5.5%,respectively),which indicates daily precipitation may not be able to capture the trend fully under the warming background,and precipi-tation at higher resolutions than the daily scale is necessary to detect trends of rainfall erosivity more accurately.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62165012 and 61665010)the Key Research and Development Projects in Gansu Province,China(Grant No.21YFIGE300)+4 种基金Gansu Province College Industry Support Plan Project(Grant Nos.2020C-23 and 2022CYZC-59)the Natural Science Foundation of Gansu Province,China(Grant Nos.21JR7RE173 and 20JR5RA494)Qinzhou District Science and Technology Plan Project(Grant No.2021-SHFZG-1442)the Scientific Research Innovation Platform Construction Project of Tianshui Normal University,Gansu Province,China(Grant No.PTJ2022-06)Science and Technology Supporting Program Project of Tianshui City(Grant Nos.2022-FZJHK-8548,2019-FZJHK-9891,and 2020-FZJHK-9757).
文摘We demonstrate a high power,widely tunable femtosecond MgO-doped periodically poled lithium niobate(MgO:PPLN)optical parametric oscillator(OPO)at 151 MHz,pumped by a Kerr-lens mode-locked Yb:KGW laser.With a maximum pump power of 7 W,the OPO is capable of delivering as high as 2.2 W of the signal centered around 1500 nm with tunable signal spectrum ranges of 1377 nm-1730 nm at an extraction efficiency of 31.4%,which exhibits a long-term passive power stability better than 0.71%rms over 4 h.The maximum idler bandwidths of 185 nm at 3613 nm are obtained across the idler tuning ranges of 2539 nm-4191 nm.By compensating intracavity dispersion,the signal has the shortest pulse duration of 170 fs at 1428 nm.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 62165012 and 61665010)Key research and development projects in Gansu Province (Grant No. 21YFIGE300)+5 种基金Gansu Province College Industry Support Plan Project (Grant Nos. 2020C-23 and 2022CYZC-59)Department of Education of Gansu Province: The Education Project of Open Competition for the Best Candidates (Grant No. 2021jyjbgs-06)Gansu Provincial University Innovation Fund Project (Grant No. 2021B-190)Qinzhou District Science and Technology Plan Project (Grant No. 2021-SHFZG1442)Gansu Province College Young Doctor Support Project (Grant No. 2023QB-013)Gansu Province Excellent Graduate Innovation Star Project (Grant No. 2022CXZX796)。
文摘A direct Kerr-lens mode-locked Tm:LuYO_(3)ceramic laser without the aid of any mode-locked starting element is reported for the first time. A pulse duration as short as 259 fs and a maximum average output power of 326 m W are obtained at a repetition rate of 97.1 MHz. The corresponding optical spectrum centered at 2053 nm exhibits a bandwidth of 19.8 nm,which indicates the presence of nearly Fourier transform-limited pulses. Such a Kerr-lens mode-locked Tm:LuYO_(3)ceramic laser is a promising ultrashort pulse source, with both the excellent laser characteristics of Tm:LuYO3and the high-power 790 nm laser diode pumping scheme.
基金supported by General project of Shandong Provincial Natural Science Foundation(ZR2020MC103,ZR2021MC040)Agricultural Innovation Project of Shandong Academy of Agricultural Sciences(CXGC2022B06,CXGC2022F33).
文摘In recent years,peanut yield and quality are more seriously affected by pod rot disease in China.However,managing this disease has proven challenging due to the wide host range of its pathogens.In this study,four soil samples were collected from fields with pod rot disease in Hebei Province,and 454 pyrosequencing was used to analyze the fungal communities structure within them.All 38490 ITS high-quality sequences were grouped into 1203 operational taxonomic units,the fungal community diversity of four soil samples was evaluated and compared using Shannon index and Simpson index.The results showed that members of Ascomycota were dominant,followed by Basidiomycota.According to the BLAST results at the species level,Guehomyces had the highest abundance,accounting for about 7.27%,followed by Alternaria,Fusarium,and Davidiella.The relative abundance of Fusarium oxysporum isolated from rotting peanuts in soil with peanut rot was higher than that in the control,indicating that Fusarium oxysporum might be one of the main pathogenic fungus of peanut rot in this area.This study delved into the broader fungal community associated with peanut pod rot,providing a theoretical foundation for preventing and treating this disease in agriculture.
文摘The droplet size, size distribution, refractive index, and temperature can be measured simultaneously by the rainbow technique. In the present work, the rainbow scattering diagram for a spherical droplet in the secondary rainbow region is simulated by the use of the generalized Lorenz-Mie theory. For achieving high spatial resolution in denser droplet sprays, a focused Gaussian beam is used. For droplet characterization, different inversion algorithms are investigated, which includes trough-trough (<em>θ</em><sub>min1</sub> and <em>θ</em><sub>min2</sub>) method and inflection-inflection (<em>θ</em><sub>inf1</sub> and <em>θ</em><sub>inf2</sub>) method. For the trough-trough algorithm, the absolute error of the refractive index is between −6.4 × 10<sup>−4</sup> and 1.7 × 10<sup>−4</sup>, and the error of the droplet radius is only between −0.55% and 1.77%. For the inflection-inflection algorithm, the maximum absolute error of the inverted refractive index is less than −1.1 × 10<sup>−3</sup>. The error of the droplet radius is between −0.75% and 5.67%.
文摘China’s recently announced directive on tackling climate change,namely,to reach carbon peak by 2030 and to achieve carbon neutrality by 2060,has led to an unprecedented nationwide response among the academia and industry.Under such a directive,a rapid increase in the grid penetration rate of solar in the near future can be fully anticipated.Although solar radiation is an atmospheric process,its utilization,as to produce electricity,has hitherto been handled by engineers.In that,it is thought important to bridge the two fields,atmospheric sciences and solar engineering,for the common good of carbon neutrality.In thisüberreview,all major aspects pertaining to solar resource assessment and forecasting are discussed in brief.Given the size of the topic at hand,instead of presenting technical details,which would be overly lengthy and repetitive,the overarching goal of this review is to comprehensively compile a catalog of some recent,and some not so recent,review papers,so that the interested readers can explore the details on their own.
文摘The film contained L-cysteine and gold nanoparticles were provided by self-assembled monolayers (SAMs) and potentiostatic electrodeposition technology on the gold electrode. Two methods were used to study the film: In the first, cyclic voltammetry (CV) was used to inspect the functional groups of the film and the same time hydroquinone was chosen to be a probe molecule in the based solution;secondly, based on analytical technology of scanning electrochemical microscopy (SECM), the heterogeneous rate constant (keff) between solid phase (the modified electrode) and liquid phase (K3Fe(CN)6) was obtained. As a result, the better binary catalysis of hydroquinone was demonstrated and the heterogeneous rate constant (keff) is the greater at 8 h for L-cysteine self-assembled monolayers (SAMs).
基金funded by the National Natural Science Foundation of China,No.30672096
文摘The posterior rootlets in L6 and S1 spinal cord of adult male Sprague-Dawley rats underwent electrostimulation. The bladder pressure, urethral perfusion pressure and intracavernous pressure were recorded. When some posterior rootlets of L6 and Sl were electrostimulated, the intracavernous pressure peaked rapidly, but the bladder pressure and the urethral perfusion pressure curve did not show great change. When other rootlets were stimulated, the bladder pressure changed greatly, but the urethral perfusion pressure and the intracavernous pressure did not show great change. When different rootlets were stimulated, the urethral perfusion pressure changed maximally, but there were no great changes in bladder pressure or intracavernous pressure. Furthermore, stimulation of some rootlets produced simultaneous changes in two or three different pressure measures mentioned above. The results demonstrate that regulation by L6 and S1 posterior rootlets of the rat bladder detrusor, external urethral sphincter and penis cavernous body are significantly distinct. Different rootlets can be distinguished by electrostimulation.
基金This research was supported by National Natural Science Foundation of China(52005387,52025056)Project funded by China Postdoctoral Science Foundation(2020M673380)Fundamental Research Funds for the Central Universities.
文摘Recently,deep learning(DL)has been widely used in the field of remaining useful life(RUL)prediction.Among various DL technologies,recurrent neural network(RNN)and its variant,e.g.,long short-term memory(LSTM)network,have gained extensive attention for their ability to capture temporal dependence.Although existing RNN-based methods have demonstrated their RUL prediction effectiveness,they still suffer from the following two limitations:1)it is difficult for the RNN to directly extract degradation features from original monitoring data and 2)most RNN-based prognostics methods are unable to quantify RUL uncertainty.To address the aforementioned limitations,this paper proposes a new prognostics method named residual convolution LSTM(RC-LSTM)network.In the RC-LSTM,a new ResNet-based convolution LSTM(Res-ConvLSTM)layer is stacked with a convolution LSTM(ConvLSTM)layer to extract degradation representations from monitoring data.Then,under the assumption that the RUL follows a normal distribution,an appropriate output layer is constructed to quantify the uncertainty of prediction results.Finally,the effectiveness and superiority of the RC-LSTM are verified using monitoring data from accelerated bearing degradation tests.
基金supported by the National Natural Science Foundation of China(31271636)the China Agriculture Research System(CARS-04)。
文摘Soybean(Glycine max[L.]Merr.)is a food and oil crop whose growth and yield are influenced by root and nodule development.In the present study,Gm NMHC5 was found to promote the formation of nodules in overexpressing mutants.In contrast,the number of nodules in Gmnmhc5 edited with CRISPR/Cas9 decreased sharply.In 35 S:Gm NMHC5 mutants,expression levels of genes involved in nodulation were significantly up-regulated.Both in vitro and in vivo biochemical analyses showed that Gm NMHC5 directly interacted with Gm GAI(a DELLA protein),and the content of gibberellin 3(GA_(3))in overexpressing mutants was lower than that in the wild type.These results revealed that Gm NMHC5 participates in the classical GA signaling pathway,and may regulate the content of GA_3 to match the optimal concentration required for nodule formation,thereby promoting nodulation by directly interacting with Gm GAI.A model illustrating the mechanism by which Gm NMHC5 promotes soybean nodulation is presented.
基金Supported by: the National Natural Science Foundation of China, No. 30672096
文摘BACKGROUND: Studies have demonstrated that selective innervation of the sacral nerve tract to the bladder plays an important role in bladder functional reconstruction following spinal cord injury. However, there are very few studies reporting detailed morphological characteristics of urogenital center and lumbosacral nerve roots. OBJECTIVE: To analyze the spinal cord segment of the lumbosacral spinal cord urogenital center, and to observe morphological characteristics. DESIGN, TIME AND SETTING: A neuroanatomical study was performed at the Laboratory of Neuroanatomy, Peking University Health Science Center between September 2007 and March 2008. MATERIALS: Horseradish peroxidase-conjugated cholera toxin B subunit (CB-HRP) was purchased from Sigma, USA; surgical microscope was purchased from Zhenjian Zhongtian Optical Instrument, Jiangsu Province, China; BCL-420 biological and functional experimental system was purchased from Taimeng Science and Technology, Sichuan Province, China. METHODS: A total of 36 adult, Sprague Dawley rats were randomly assigned to groups A (n = 10), B (n = 10), C (n = 10), and D (n = 6). CB-HRP (3%, 10-15 μL) was injected into the bladder detrusor muscle (group A), external urethral sphincter (group B), and perineal muscles (group C), respectively. Rats in group D were not given any treatments. MAIN OUTCOME MEASURES: At 72 hours after CB-HRP injection, CB-HRP-positive neurons were analyzed in lumbosacral segments using 3, 3', 5, 5'-tetramethylbenzidine staining and an Olympus optic microscope, while anatomical structures in the respective spinal nerve tract were observed using a surgical microscope. RESULTS: CB-HRP-positive neurons were distributed in the L6-S1 segments of the spinal cord, and neurons primarily innervating the bladder detrusor muscle were located at the sacral parasympathetic nucleus and the intermediolateral nucleus. In addition, neurons that primarily innervate the external urethral sphincter and perineal muscles were observed in the ventrolateral portion (Onuf's nucleus). The lumbar-sacral nerve roots were composed of varying nerve tracts, Le., they were typically divided into 1-2 sub-bundles, and the sub-bundles were then divided into 2-3 tiny bundles. There were extensive fibro-connections between the rootlets. CONCLUSION: The urogenital center in Sprague Dawley rats was located in the L6 -S1 segments of the spinal cord, and the rootlets were clearly observed. Therefore, this rat experimental model could be utilized for highly selective anterior/posterior rhizotomy.
基金supported by the National Key Research and Development of China (No. 2018YFA0404503)NSFC (grant Nos. 12033008 and 11988101)+4 种基金the K.C.Wong Education Foundation, and the science research grants from the China Manned Space Project with Nos. CMS-CSST-2021-A03 and CMS-CSST-2021-A07support from the joint Sino-German DFG research Project The Cosmic Web and its impact on galaxy formation and alignment (DFG-LI 2015/5-1, NSFC No. 11861131006)the support of the Shanghai International partners project (No. 19590780200)the support from NSFC (12022307)the Yangyang Development Fund。
文摘We study the relation between halo concentration and mass(c-M relation) using galaxy catalogs of the Seventh and Eighth Data Releases of the Sloan Digital Sky Survey(SDSS DR7 and DR8). Assuming that the satellite galaxies follow the distribution of dark matter, we derive the halo concentration by fitting the satellite radial profile with a Nararro Frank and White(NFW) format. The derived c-M relation covers a wide halo mass range from10^(11.6)to 10^(14.1)M_(⊙). We confirm the anti-correlation between the halo mass and concentration as predicted in cosmological simulations. Our results are in good agreement with those derived using galaxy dynamics and gravitational lensing for halos of 10^(11.6)– 10^(12.9)M_(⊙), while they are slightly lower for halos of 10^(12.9)– 10^(14.1)M_(⊙).This is because blue satellite galaxies are less concentrated, especially in the inner regions. Instead of using all satellite galaxies, red satellites could be better tracers of the underlying dark matter distribution in galaxy groups.
基金the Science and Technology Project of the State Grid Shandong Electric Power Company:Research on the vulnerability and prevention of the electrical cyber-physical monitoring system based on interdependent networksthe National Natural Science Foundation of China(61873057)and the Education Department of Jilin Province(JJKH20200118KJ).
文摘This paper presents an effective and feasible method for detecting dynamic load-altering attacks(D-LAAs)in a smart grid.First,a smart grid discrete system model is established in view of D-LAAs.Second,an adaptive fading Kalman filter(AFKF)is designed for estimating the state of the smart grid.The AFKF can completely filter out the Gaussian noise of the power system,and obtain a more accurate state change curve(including consideration of the attack).A Euclidean distance ratio detection algorithm based on the AFKF is proposed for detecting D-LAAs.Amplifying imperceptible D-LAAs through the new Euclidean distance ratio improves the D-LAA detection sensitivity,especially for very weak D-LAA attacks.Finally,the feasibility and effectiveness of the Euclidean distance ratio detection algorithm are verified based on simulations.
基金supported in part by the National Key R&D Program of China under 2019YFB1503700by the National Natural Science Foundation of China under Grant 51677169。
文摘Wound field switched flux(WFSF)machines exhibits characteristics of the simple robust rotor,flexible flux-adjustable capability,and no risk of demagnetization.However,they suffer from a poor torque density compared with permanent magnet machines due to the saturation.Therefore,in this paper,two WFSF machines with single-and double-layer DC windings,respectively,are optimized for the maximum torque.The end-winding(EW)lengths differ in these two machines,which can affect the optimal design.Design parameters including the DC to armature winding copper loss ratio,slot area ratio and split ratio are optimized when two machines have the same copper loss and overall sizes.In addition,the influence of the flux density ratio,total copper loss,air-gap length and aspect ratio on the optimal split ratio is investigated using the finite element method and results are explained through the analytical model accounting for the saturation.It is discovered that the EWs have no effect on the optimal copper loss ratio,which is unity.In terms of the slot area ratio,the machine with single-layer DC windings prefers smaller DC slot areas than armature slot areas.In the WFSF machine with longer EWs,the optimal split ratio becomes smaller.Moreover,compared with other parameters,the flux density ratio can significantly affect the optimal split ratio.
基金supported by grants from the National Natural Science Foundation of China Grant Awards(No.81960669)The National High Level Hospital Clinical Research Funding(No.2022-GSP-GG-22)+1 种基金Capital’s Funds for Research and Application of Clinical Diagnosis and Treatment Technology(No.Z191100006619121)National Clinical Research Center for Cardiovascular Diseases,Fuwai Hospital,Chinese Academy of Medical Sciences(No.NCRC2020015)
文摘Introduction:Observational studies have revealed an association between waist circumference(WC)and atrial fibrillation(AF).However,it is difficult to infer a causal relationship from observational studies because the observed associations could be confounded by unknown risk factors.Therefore,the causal role of WC in AF is unclear.This study was designed to investigate the causal association between WC and AF using a two-sample Mendelian randomization(MR)analysis.Methods:In our two-sample MR analysis,the genetic variation used as an instrumental variable for MR was acquired from a genome-wide association study(GWAS)of WC(42 single nucleotide polymorphisms with a genetic significance of P<5×10^(-8)).The data of WC(from the Genetic Investigation of ANthropometric Traits consortium,containing 232,101 participants)and the data of AF(from the European Bioinformatics Institute database,containing 55,114 AF cases and 482,295 controls)were used to assess the causal role of WC on AF.Three different approaches(inverse variance weighted[IVW],MR-Egger,and weighted median regression)were used to ensure that our results more reliable.Results:All three MR analyses provided evidence of a positive causal association between high WC and AF.High WC was suggested to increase the risk of AF based on the IVW method(odds ratio[OR]=1.43,95%confidence interval[CI],1.30-1.58,P=2.51×10^(-13)).The results of MR-Egger and weighted median regression exhibited similar trends(MR-Egger OR=1.40[95%CI,1.08-1.81],P=1.61×10^(-2);weighted median OR=1.39[95%CI,1.21-1.61],P=1.62×10^(-6)).MR-Egger intercepts and funnel plots showed no directional pleiotropic effects between high WC and AF.Conclusions:Our findings suggest that greater WC is associated with an increased risk of AF.Taking measures to reduce WC may help prevent the occurrence of AF.
基金supported by the National Natural Science Foundation of China(Grant No.52071318).
文摘The oxidation behavior and kinetics of Ti_(2)AlC-20vol.%TiB_(2) composite at 600-900℃ in air were investigated.The results showed that the oxidation kinetics of the composite followed a logarithmic law within the given temperature range,which indicated that the composites had excellent oxidation resistance.The selective oxidation of Al in Ti_(2)AlC was greatly enhanced,which facilitated the formation of a continuous and dense protective layer of Al_(2)O_(3).Meanwhile,the existence of molten B_(2)O_(3) inhibited the outward diffusion of Ti and inward diffusion of oxygen,which prevented the growth of anatase TiO_(2) at 600℃ and rutile TiO_(2) at 700-900℃.Therefore,the incorporation of TiB_(2) completely inhibited the abnormally rapid oxidation of bulk Ti_(2)AlC at 600℃ and improved its oxidation resistance at 700-900℃.
基金Defense Advanced Research Projects Agency(HR001122C0017).
文摘Frequency microcombs with microwave and millimeter-wave repetition rates provide a compact solution for coherent communication and information processing.The implementation of these microcombs using a CMOS-compatible platform further paves the way for large-scale photonic integration and modularity.Here,we demonstrate free-running soliton microcombs with K-band repetition rates with very low phase noise over a 4 GHz pump detuning range reaching−117(−123)dBc/Hz at 10 kHz offset for a 19.7(10)GHz carrier without active pump stabilization,exceeding commercial electronic microwave oscillators at frequency offsets above 40 kHz.The minimum laser noise to soliton microwave signal transduction factor observed is−73dB.This noise performance is achieved using a hybridized dual-mode for soliton generation to achieve passive thermal stabilization and minimal soliton spectrum shift from prior Raman scattering and dispersive wave formation.We further examine the locking of the repetition rate to an external ultrastable photonic oscillator to illustrate the feasibility of phase noise suppression below the thermorefractive noise limits of microresonator frequency combs.
基金supported by the National Outstanding Youth Natural Science Foundation of China (82022076)the Young Qihuang Scholar of the“Tens of millions”talent project of China.
文摘Vascular complications of diabetes pose a severe threat to human health.Prevention and treatment protocols based on a single vascular complication are no longer suitable for the long-term management of patients with diabetes.Diabetic panvascular disease(DPD)is a clinical syndrome in which vessels of various sizes,including macrovessels and microvessels in the cardiac,cerebral,renal,ophthalmic,and peripheral systems of patients with diabetes,develop atherosclerosis as a common pathology.Pathological manifestations of DPDs usually manifest macrovascular atherosclerosis,as well as microvascular endothelial function impairment,basement membrane thickening,and microthrombosis.Cardiac,cerebral,and peripheral microangiopathy coexist with microangiopathy,while renal and retinal are predominantly microangiopathic.The following associations exist between DPDs:numerous similar molecular mechanisms,and risk-predictive relationships between diseases.Aggressive glycemic control combined with early comprehensive vascular intervention is the key to prevention and treatment.In addition to the widely recommended metformin,glucagon-like peptide-1 agonist,and sodium-glucose cotransporter-2 inhibitors,for the latest molecular mechanisms,aldose reductase inhibitors,peroxisome proliferator-activated receptor-γagonizts,glucokinases agonizts,mitochondrial energy modulators,etc.are under active development.DPDs are proposed for patients to obtain more systematic clinical care requires a comprehensive diabetes care center focusing on panvascular diseases.This would leverage the advantages of a cross-disciplinary approach to achieve better integration of the pathogenesis and therapeutic evidence.Such a strategy would confer more clinical benefits to patients and promote the comprehensive development of DPD as a discipline.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2021YFE0113800)the National Key Research and Development Program of China(Grant No.2021YFD1500705)the Project for Recruited Talents to Start Up Their Work and Research in Beijing Normal University at Zhuhai(310432116).
文摘Northeast China(NEC)is one of the vital commercial grain bases in China and it has suffered from soil erosion due to prolonged cultivation and lack of protection.To determine long-term trends of precipi-tation and rainfall erosivity over NEC during the latest decades,daily precipitation for the entire year during 1961-2020 and hourly precipitation for the warm season(May to September)during 1971-2020 were collected for 192 and 126 stations,respectively.Three seasons,including the cold season(October to April),early warm season(May to June),and late warm season(July to September)were divided according to the combination of precipitation and vegetation.Results demonstrate:(1)Daily precipita-tion reveals total precipitation and rainfall erosivity in the cold season and early warm season increase significantly at relative rates of 3.1%-6.1%compared with the average during 1961-2020,and those in the late warm season decrease insignificantly.(2)Hourly precipitation reveals storms occurring in the early and late warm seasons have undergone significant increasing changes,which shift towards longer storm duration,larger amount,peak intensity,kinetic energy,and rainfall erosivity during 1971-2020.Moreover,the frequency of extreme storms increased.(3)Rainfall erosivities estimated from daily pre-cipitation during 1971-2020 increase insignificantly for the early and late warm season,whereas those from hourly precipitation increase significantly(6.1%and 5.5%,respectively),which indicates daily precipitation may not be able to capture the trend fully under the warming background,and precipi-tation at higher resolutions than the daily scale is necessary to detect trends of rainfall erosivity more accurately.