Soil nitrogen(N)cycling is one of the most critical biogeochemical cycles,and N cycling-related microorganisms are the primary driving force behind N cycling in natural environments.The large karst sinkholes in China,...Soil nitrogen(N)cycling is one of the most critical biogeochemical cycles,and N cycling-related microorganisms are the primary driving force behind N cycling in natural environments.The large karst sinkholes in China,known as Tiankengs,harbor abundant unique biological resources due to their particular environmental conditions.However,N cycling-related microorganisms in Tiankeng soils and their connection to ecosystem processes remain poorly studied.In this study,we investigated the distribution patterns and genomic diversity of N cycling-related microorganisms both inside and outside the Luohun cave Tiankeng in Guizhou,China,utilizing high-throughput sequencing and other techniques.The results indicated that the diversities and abundances of denitrifying bacteria,ammonia-oxidizing bacteria,and ammonia-oxidizing archaea communities inside the Tiankeng were higher than those outside the Tiankeng;however,the microbial network relationships were more fragile inside the Tiankeng.The most abundant species of denitrifying bacteria,ammonia-oxidizing bacteria,and ammonia-oxidizing archaea inside the Tiankeng were unclassified_p_Proteobacteria(47.8%),unclassified_k_norank(AOB,OTU121,37.3%),and unclassified_g_norank_f_norank_o_norank_c_environmental_samples(55.7%),respectively;outside the Tiankeng,they were unclassified_k_norank_d_bacteria(54.5%),unclassified_k_norank(AOB,OTU121,48.1%),and unclassified_k_norank(AOA,OTU70,49.6%),respectively.Additionally,the N content inside the Tiankeng was significantly lower(P<0.05)under the influence of these N cycling-related microorganisms,whereas the nutrient contents were higher than that outside the Tiankeng.To the best of our knowledge,this is the first report on the crucial microbial distribution patterns driving N cycling in karst Tiankengs and provides new insights into the structure and potential functions of N cycling-related microorganisms in the unique ecological environment of fragile Tiankeng ecosystems.展开更多
Non-destructive time-series assessment of chlorophyll content in flag-leaf(FLC)accurately mimics the senescence rate and the identification of genetic loci associated with senescence provides valuable knowledge to imp...Non-destructive time-series assessment of chlorophyll content in flag-leaf(FLC)accurately mimics the senescence rate and the identification of genetic loci associated with senescence provides valuable knowledge to improve yield stability under stressed environments.In this study,we employed both unmanned aerial vehicles(UAVs)equipped with red–green–blue(RGB)camera and ground-based SPAD-502 instrument to conduct temporal phenotyping of senescence.A total of 262 recombinant inbred lines derived from the cross of Zhongmai 578/Jimai 22 were evaluated for senescence-related traits across three environments,spanning from heading to 35 d post-anthesis.The manual senescence rate(MSR)was quantified using the FLC and the active accumulated temperature,and UAV derived vegetation index were utilized to assess the stay-green rate(USG)facilitating the identification of senescent and stay-green lines.Results indicated that higher senescence rates significantly impacted grain yield,primarily by influencing thousand-kernel weight,and plant height.Quantitative trait loci(QTL)mapping for FLC,USG,and MSR using the 50K SNP array identified 38 stable loci associated with RGB-based vegetation indices and senescence-related traits:among which 19 loci related to senescence traits from UAV and FLC were consistently detected across at least two growth stages,with nine loci likely representing novel QTL.This study highlights the potential of UAV-based high-throughput phenotyping and phenology in identifying critical loci associated with senescence rates in wheat,validating the relationship between senescence rates and yield-related traits in wheat,offering valuable opportunities for gene discovery and significant applications in breeding programs.展开更多
The majority(up to 90%)of riverine materials is transported from the continent to the ocean mainly in flood events.It is thus crucial to characterize the geochemistry of elements and their flux in river system in orde...The majority(up to 90%)of riverine materials is transported from the continent to the ocean mainly in flood events.It is thus crucial to characterize the geochemistry of elements and their flux in river system in order to better constrain their global biogeochemical cycling and impact on the oceanic ecosystem.However,the geochemical behavior including the distribution,migration and partitioning of typical metal elements amongst diff erent phases,during hydrodynamic flood event remains still to be well explored.Here,we investigated the geochemical behaviors of typical metal elements in dissolved phase and suspended particulate matter collected from a single flood event in the natural Chishui River,Southwest China.The results showed clearly that the geochemistry of metal elements was largely controlled by the hydrodynamic eff ect,of which the diff erent flowrates introduce a natural sorting of diff erent mineral particles transported at diff erent flood stages,depending on their shape,size and density.The maximum concentrations of alkaline and alkaline earth metals(Li,Mg,K,Rb and Sr)in SPM appeared before the flood peak,which was largely controlled by aluminosilicate minerals.However,transition metals(Cr,Mn,Fe,Ni and Cu)showed their abundance peaks lagging behind the flowrate summit,as a result of the late arrival of coarse particles or heavy minerals,evidenced by the mineralogical phase analysis.In addition,the distribution coe fficient(K_(d))between particulate and dissolved loads were lower and stable for soluble alkali/alkaline earth metals which could be aff ected by pH,while higher and fluctuant for transition metals that were largely influenced by SPM content.Overall,the present study reveals clear eff ects of hydrodynamic sorting on the geochemistry of metal elements during the flood event of the natural Chishui River,which should be taken into account when characterizing the riverine flux and their impact on marine ecosystem.展开更多
Under the background of new engineering,the reform of the comprehensive practical course system for mechanical and electronic engineering majors actively responds to the challenges posed by the new round of technologi...Under the background of new engineering,the reform of the comprehensive practical course system for mechanical and electronic engineering majors actively responds to the challenges posed by the new round of technological revolution and industrial transformation to higher education,cultivating top-notch innovative intellectuals with comprehensive engineering qualities,meeting the requirements of being able to solve complex engineering problems rather than just cognitive capabilities,forming two core courses through reconstructing and reshaping the core courses of the major.The core courses include Drive,Measurement,and Control I and Drive,Measurement,and Control II,which highlight the comprehensive framework of mechanical and electronic engineering professional knowledge,continuing the comprehensive practical course system based on the unity of knowledge and practice,following the trend of new engineering,highlighting the practicality of professional innovation,assisting engineering education reform,and promoting high-quality development of new engineering professionals cultivation.展开更多
This article introduces a cable-driven lower limb rehabilitation robot with movable distal anchor points(M-CDLR).The traditional cable-driven parallel robots(CDPRs)control the moving platform by changing the length of...This article introduces a cable-driven lower limb rehabilitation robot with movable distal anchor points(M-CDLR).The traditional cable-driven parallel robots(CDPRs)control the moving platform by changing the length of cables,M-CDLR can also adjust the position of the distal anchor point when the moving platform moves.The M-CDLR this article proposed has gait and single-leg training modes,which correspond to the plane and space motion of the moving platform,respectively.After introducing the system structure configuration,the generalized kinematics and dynamics of M-CDLR are established.The fully constrained CDPRs can provide more stable rehabilitation training than the under-constrained one but requires more cables.Therefore,a motion planning method for the movable distal anchor point of M-CDLR is proposed to realize the theoretically fully constrained with fewer cables.Then the expected trajectory of the moving platform is obtained from the motion capture experiment,and the motion planning of M-CDLR under two training modes is simulated.The simulation results verify the effectiveness of the proposed motion planning method.This study serves as a basic theoretical study of the structure optimization and control strategy of M-CDLR.展开更多
BACKGROUND:A20 may be a neuroprotective factor.Herein,we aimed to investigate whether serum A20 levels were associated with disease severity,delayed cerebral ischemia(DCI),and outcome after aneurysmal subarachnoid hem...BACKGROUND:A20 may be a neuroprotective factor.Herein,we aimed to investigate whether serum A20 levels were associated with disease severity,delayed cerebral ischemia(DCI),and outcome after aneurysmal subarachnoid hemorrhage(aSAH).METHODS:In this prospective cohort study containing 112 aSAH patients and 112 controls,serum A20 levels were quantified.At 90 d poststroke,Modified Rankin Scale(MRS) scores≥3 were defined as a poor outcome.All correlations and associations were assessed using multivariate analysis.RESULTS:Compared with controls,there was a significant elevation of serum A20 levels in patients(median 123.7 pg/mL vs.25.8 pg/mL;P<0.001).Serum A20 levels were independently correlated with Hunt-Hess scores(β 9.854;95% confidence interval [95% CI] 2.481-17.227,P=0.009) and modified Fisher scores(β 10.349,95% CI 1.273-19.424,P=0.026).Independent associations were found between serum A20 levels and poor outcome(odds ratio [OR] 1.015,95%CI 1.000-1.031,P=0.047) and DCI(OR 1.018,95% CI 1.001-1.035,P=0.042).Areas under the curve for predicting poor outcome and DCI were 0.771(95% CI 0.682-0.845) and 0.777(95% CI 0.688-0.850),respectively.Serum A20 levels ≥128.15 pg/mL predicted poor outcome,with a sensitivity of 73.9% and specificity of 74.2%,and A20 levels ≥160.55 pg/mL distinguished the risk of DCI with65.5% sensitivity and 89.2% specificity.Its ability to predict poor outcome and DCI was similar to those of Hunt-Hess scores and modified Fisher scores(both P>0.05).CONCLUSION:Enhanced serum A20 levels are significantly associated with stroke severity and poor clinical outcome after aSAH,implying that serum A20 may be a potential prognostic biomarker for aSAH.展开更多
Using of diffractive optical elements (DOE) in the Schupmann system offer a new way for the construction of ultra-large aperture telescope. The Fresnel Corrector, one of the DOEs, is the key device in the Schupmann sy...Using of diffractive optical elements (DOE) in the Schupmann system offer a new way for the construction of ultra-large aperture telescope. The Fresnel Corrector, one of the DOEs, is the key device in the Schupmann system, which is used to correct the chromatic aberration introduced by the diffractive primary lens called Magnifying Glass. Generally, in a large aperture telescope (>20 m), the Fresnel Corrector is a diffractive lens with a large aperture and a small f-number, which is difficult to process. In this article, an improved device with a small F number but a large rim feature size, called amplitude and phase hybrid modulation Fresnel diffractive optical element (APHMFDOE), is used here as the Fresnel corrector. First, APHMFDOE with appropriate parameters is designed to match the dispersion of the Magnifying Glass so that the system meets the achromatic condition. Second, the optical characteristics of this improved system are simulated and compared with those of the general system based on the conventional Fresnel corrector. Our approach introduces a new dispersion correction device, which not only can eliminate the chromatic aberration caused by Magnifying Glass, but also can reduce the processing difficulty of Fresnel Corrector.展开更多
With the arrival of the intelligence era of Industry 4.0,social development has shown complex and diversified characteristics,gradually forming an innovation ecological environment constructed by vertical interaction ...With the arrival of the intelligence era of Industry 4.0,social development has shown complex and diversified characteristics,gradually forming an innovation ecological environment constructed by vertical interaction of multi-layer innovation systems and horizontal collaboration of multiple organizations and departments,which has posed extremely challenging requirements for higher engineering education to cultivate engineering talents with comprehensive engineering qualities who can solve complex engineering problems.However,practical engineering problems may involve a complex knowledge chain of interdisciplinary and multi-disciplinary cross-coupling.Therefore,higher engineering education needs to form a new interdisciplinary and multi-disciplinary integrated engineering innovation talent training system.Based on the characteristics of the mechanical and electronic engineering major,we will reshape and reconstruct the core courses of the mechanical and electronic engineering major.Two core courses are formed:Drive and Measurement and Control I and Drive and Measurement and Control II,with information flow and energy flow as the main lines,following up with the comprehensive practical curriculum system based on the unity of knowledge and practice and ability-oriented thinking,supporting teaching objectives,promoting students’individual development,and providing guidelines for relevant curriculum reforms.展开更多
According to the GFCI ranking from 2018-2020,Hong Kong fell from third to sixth,surpassing cities in other Asian countries and some inland cities in China.Hong Kong’s marginalization has intensified because of the im...According to the GFCI ranking from 2018-2020,Hong Kong fell from third to sixth,surpassing cities in other Asian countries and some inland cities in China.Hong Kong’s marginalization has intensified because of the impact of the new crown epidemic and anti-repair incidents.However,Hong Kong’s marginalization is indeed somewhat inappropriate.As far as the situation is concerned,Hong Kong still has a strong competitiveness,although it is lagging behind,but Hong Kong should think deeply about the strategy and system of“one country,two systems”,believe in the country’s strategic intention and adjust its state in time to re-exclude the public’s understanding of its marginalization.展开更多
Dissipative Kerr solitons in optical microcavities enable various stable states involving multi-soliton and perfect soliton crystal(PSC),leading to widespread applications.However,the triggering condition and switchin...Dissipative Kerr solitons in optical microcavities enable various stable states involving multi-soliton and perfect soliton crystal(PSC),leading to widespread applications.However,the triggering condition and switching dynamics of the PSC and multi-soliton states(MSs)remain unexplored,which makes it challenging to selectively trigger the PSC/MS state for distinct area.Here,we theoretically and experimentally investigate the realization and switching of multi-/single-soliton and PSC states by engineering the periodic intracavity potential field constructed by control laser in a high-Q microrod cavity.We show that,by varying the parameters of the control laser,the PSC and multi-/single-soliton states can be selectively excited,and the soliton dynamics depends on the chaotic regime.We establish a fundamental link between the PSC switching behavior with the transient chaotic regime.Using such relation,we also demonstrate the switching and dynamical phenomena involving the conversion between PSC and MS,and soliton crystal melting and recrystallization.Our work provides additional routes for manipulation of soliton temporal and spectral profiles in optical microcavity systems and enables soliton generation on demand with desired states inside a single device.展开更多
In quantitative genomic analysis of wheat plant height(PH),the average height of a few representative plants is typically used to represent the PH of the entire plot,which overlooks the variation in height among other...In quantitative genomic analysis of wheat plant height(PH),the average height of a few representative plants is typically used to represent the PH of the entire plot,which overlooks the variation in height among other plants.Extracting different height quantiles from canopy point clouds can address this limitation.For this purpose,low-cost UAV cross-circling oblique(CCO)imaging,combined with structure-from-motion(SfM)and multi-view stereopsis(MVS),was employed to generate precise canopy point clouds for 262 F5 recombinant inbred lines(Zhongmai 578×Jimai 22)across seven environments.Multi-level 3D-PH measurements were extracted from six height quantiles,revealing a strong correlation(mean r=0.95)between 3D-PH and field-measured PH(FM-PH)across environments.The 90%and 92%height quantiles showed the closest agreement with FM-PH compared to other quantiles.Eleven stable quantitative trait loci(QTLs)associated with multi-level 3D-PH were identified using a 50K single nucleotide polymorphism array.Among these,QPhzj.caas-3A.2(detected by 3D-PH)and QPhzj.caas-7A.1(detected by both FM-PH and 3D-PH)represented potential novel loci.KASP markers for these QTLs were developed and validated.Furthermore,within the intervals of QPhzj.caas-5A and QPhzj.caas-3B(both were detected by 3D-PH),two candidate genes associated with PH regulation were identified:TaGL3-5A and Rht5,respectively.Corresponding KASP markers for these genes were also developed and validated.This study high-lighted the advantages of 3D model and multi-level 3D-PH in elucidating the genetic basis of crop height,and provided a precise and objective basis for advancing wheat breeding programs.展开更多
A highly sensitive temperature sensor was developed using a thin-walled Si O2hollow microrod resonator(SHMR)to excite Lorentz resonance and Fano resonance.The SHMR has a high Q factor(3.16×10^(7))and concise reso...A highly sensitive temperature sensor was developed using a thin-walled Si O2hollow microrod resonator(SHMR)to excite Lorentz resonance and Fano resonance.The SHMR has a high Q factor(3.16×10^(7))and concise resonance modes.Moreover,the SHMR has a small wall thickness,which can effectively improve the sensitivity of the temperature sensor.The experimental results show that the sensitivity reaches 24.78 pm/℃under Lorentz resonance and further improves to 31.28 pm/℃under Fano resonance.By further reducing the wall thickness of the SHMR,the sensitivity under Lorentz resonance is increased to 34.34 pm/℃.The sensor in this study has the advantages of low cost,simple structure,high sensitivity,and satisfactory repeatability.展开更多
Two-photon polymerization lithography is a technique that provides hundreds of nanometer resolution and full geometric freedom.Several X-ray polymer refractive lenses created by this technique were characterized using...Two-photon polymerization lithography is a technique that provides hundreds of nanometer resolution and full geometric freedom.Several X-ray polymer refractive lenses created by this technique were characterized using differential phase contrast imaging(DPCI)with a microfocus X-ray grating interferometer.The beam deflection angle and wavefront phase shift of the X-ray beam through the lens were obtained.Comparative tests using synchrotron radiation sources showed that the system could measure the surface shape of X-ray refractive lenses with an accuracy of 0.4μm.This study is important for improving the fabrication process and focusing performance of X-ray refractive lenses.展开更多
In this Letter, we demonstrate high-quality(Q), millimeter-size, and V-shaped calcium fluoride crystalline resonators for modal modification. To manufacture such resonators, we develop a home-made machining system and...In this Letter, we demonstrate high-quality(Q), millimeter-size, and V-shaped calcium fluoride crystalline resonators for modal modification. To manufacture such resonators, we develop a home-made machining system and explore a detailed process. With a dedicated polished container, three special polishing steps, including grinding, smoothing, and polishing, are employed to achieve the required surface smoothness, which is characterized by less than 3 nm. An ultra-high-Q factor exceeding 108 is obtained by a coupled tapered fiber.In addition, a customized packaged structure for our disk resonator is achieved. The Q maintenance and stable spectrum are realized by sealing the coupling system in a hard disk. The simple, stable, portable, controlled, and integratable device would provide great potential in optical filters, sensors, nonlinear optics, cavity quantum electrodynamics, and especially some applications that require large resonators such as gyroscopes.展开更多
We report a broadband two-dimensional(2 D) Kerr and Raman–Kerr frequency comb generation in a silica bottle resonator accounting for azimuthal and axial degrees of freedom and pioneer a method that allows for control...We report a broadband two-dimensional(2 D) Kerr and Raman–Kerr frequency comb generation in a silica bottle resonator accounting for azimuthal and axial degrees of freedom and pioneer a method that allows for controlled and reversible switching between a four wave mixing(FWM) state and a stimulated Raman scattering state. The repetition rate of the Raman–Kerr comb is not an integer number of the free spectral range, which spans more than 242 nm with hundreds of teeth. We show that, experimentally and numerically, multiple 2 D comb regimes can be selectively accessed via dispersion engineering by exciting different orders of axial modes or modifying the curvature of the axial profile, involving cascaded FWM, Raman lasing, and Raman-assisted FWM. The effect of axial curvature on dispersion is associated with the axial mode number in bottle resonators. Our approach enables dispersion and spectral engineering flexibility in any resonator with localized axial modes.展开更多
Microresonator-based optical frequency combs are broadband light sources consisting of equally spaced and coherent narrow lines,which are extremely promising for applications in molecular spectroscopy and sensing in t...Microresonator-based optical frequency combs are broadband light sources consisting of equally spaced and coherent narrow lines,which are extremely promising for applications in molecular spectroscopy and sensing in the mid-infrared(MIR)spectral region.There are still great challenges in exploring how to improve materials for microresonator fabrication,extend spectral bandwidth of parametric combs,and realize fully stabilized soliton MIR frequency combs.Here,we present an effective scheme for broadband MIR optical frequency comb generation in a MgF_(2) crystalline microresonator pumped by the quantum cascade laser.The spectral evolution dynamics of the MIR Kerr frequency comb is numerically investigated,revealing the formation mechanism of the microresonator soliton comb via scanning the pump-resonance detuning.We also experimentally implement the modulation instability state MIR frequency comb generation in MgF_(2) resonators covering from 3380 nm to 7760 nm.This work proceeds microresonator-based comb technology toward a miniaturization MIR spectroscopic device that provides potential opportunities in many fields such as fundamental physics and metrology.展开更多
基金supported by the National Natural Science Foundation of China(No.31860023)the Light of West China Program of Chinese Academic of Sciences(No.[2019]90)+1 种基金the Basic Research Fund of Guangxi Academy of Sciences,China(No.CQZ-D-1904)the Fundamental Research Fund of the Guangxi Institute of Botany,China(Guizhiye Nos.24010 and 24012).
文摘Soil nitrogen(N)cycling is one of the most critical biogeochemical cycles,and N cycling-related microorganisms are the primary driving force behind N cycling in natural environments.The large karst sinkholes in China,known as Tiankengs,harbor abundant unique biological resources due to their particular environmental conditions.However,N cycling-related microorganisms in Tiankeng soils and their connection to ecosystem processes remain poorly studied.In this study,we investigated the distribution patterns and genomic diversity of N cycling-related microorganisms both inside and outside the Luohun cave Tiankeng in Guizhou,China,utilizing high-throughput sequencing and other techniques.The results indicated that the diversities and abundances of denitrifying bacteria,ammonia-oxidizing bacteria,and ammonia-oxidizing archaea communities inside the Tiankeng were higher than those outside the Tiankeng;however,the microbial network relationships were more fragile inside the Tiankeng.The most abundant species of denitrifying bacteria,ammonia-oxidizing bacteria,and ammonia-oxidizing archaea inside the Tiankeng were unclassified_p_Proteobacteria(47.8%),unclassified_k_norank(AOB,OTU121,37.3%),and unclassified_g_norank_f_norank_o_norank_c_environmental_samples(55.7%),respectively;outside the Tiankeng,they were unclassified_k_norank_d_bacteria(54.5%),unclassified_k_norank(AOB,OTU121,48.1%),and unclassified_k_norank(AOA,OTU70,49.6%),respectively.Additionally,the N content inside the Tiankeng was significantly lower(P<0.05)under the influence of these N cycling-related microorganisms,whereas the nutrient contents were higher than that outside the Tiankeng.To the best of our knowledge,this is the first report on the crucial microbial distribution patterns driving N cycling in karst Tiankengs and provides new insights into the structure and potential functions of N cycling-related microorganisms in the unique ecological environment of fragile Tiankeng ecosystems.
基金funded by the National Key Research and Development Program of China(2022ZD0115703)the National Natural Science Foundation of China(32372196)+1 种基金the Beijing Joint Research Program for Germplasm Innovation and New Variety Breeding(G20220628002)National Natural Science Foundation of China(32250410307)。
文摘Non-destructive time-series assessment of chlorophyll content in flag-leaf(FLC)accurately mimics the senescence rate and the identification of genetic loci associated with senescence provides valuable knowledge to improve yield stability under stressed environments.In this study,we employed both unmanned aerial vehicles(UAVs)equipped with red–green–blue(RGB)camera and ground-based SPAD-502 instrument to conduct temporal phenotyping of senescence.A total of 262 recombinant inbred lines derived from the cross of Zhongmai 578/Jimai 22 were evaluated for senescence-related traits across three environments,spanning from heading to 35 d post-anthesis.The manual senescence rate(MSR)was quantified using the FLC and the active accumulated temperature,and UAV derived vegetation index were utilized to assess the stay-green rate(USG)facilitating the identification of senescent and stay-green lines.Results indicated that higher senescence rates significantly impacted grain yield,primarily by influencing thousand-kernel weight,and plant height.Quantitative trait loci(QTL)mapping for FLC,USG,and MSR using the 50K SNP array identified 38 stable loci associated with RGB-based vegetation indices and senescence-related traits:among which 19 loci related to senescence traits from UAV and FLC were consistently detected across at least two growth stages,with nine loci likely representing novel QTL.This study highlights the potential of UAV-based high-throughput phenotyping and phenology in identifying critical loci associated with senescence rates in wheat,validating the relationship between senescence rates and yield-related traits in wheat,offering valuable opportunities for gene discovery and significant applications in breeding programs.
基金National Natural Science Foundation of China,42103008,Hongming Cai。
文摘The majority(up to 90%)of riverine materials is transported from the continent to the ocean mainly in flood events.It is thus crucial to characterize the geochemistry of elements and their flux in river system in order to better constrain their global biogeochemical cycling and impact on the oceanic ecosystem.However,the geochemical behavior including the distribution,migration and partitioning of typical metal elements amongst diff erent phases,during hydrodynamic flood event remains still to be well explored.Here,we investigated the geochemical behaviors of typical metal elements in dissolved phase and suspended particulate matter collected from a single flood event in the natural Chishui River,Southwest China.The results showed clearly that the geochemistry of metal elements was largely controlled by the hydrodynamic eff ect,of which the diff erent flowrates introduce a natural sorting of diff erent mineral particles transported at diff erent flood stages,depending on their shape,size and density.The maximum concentrations of alkaline and alkaline earth metals(Li,Mg,K,Rb and Sr)in SPM appeared before the flood peak,which was largely controlled by aluminosilicate minerals.However,transition metals(Cr,Mn,Fe,Ni and Cu)showed their abundance peaks lagging behind the flowrate summit,as a result of the late arrival of coarse particles or heavy minerals,evidenced by the mineralogical phase analysis.In addition,the distribution coe fficient(K_(d))between particulate and dissolved loads were lower and stable for soluble alkali/alkaline earth metals which could be aff ected by pH,while higher and fluctuant for transition metals that were largely influenced by SPM content.Overall,the present study reveals clear eff ects of hydrodynamic sorting on the geochemistry of metal elements during the flood event of the natural Chishui River,which should be taken into account when characterizing the riverine flux and their impact on marine ecosystem.
文摘Under the background of new engineering,the reform of the comprehensive practical course system for mechanical and electronic engineering majors actively responds to the challenges posed by the new round of technological revolution and industrial transformation to higher education,cultivating top-notch innovative intellectuals with comprehensive engineering qualities,meeting the requirements of being able to solve complex engineering problems rather than just cognitive capabilities,forming two core courses through reconstructing and reshaping the core courses of the major.The core courses include Drive,Measurement,and Control I and Drive,Measurement,and Control II,which highlight the comprehensive framework of mechanical and electronic engineering professional knowledge,continuing the comprehensive practical course system based on the unity of knowledge and practice,following the trend of new engineering,highlighting the practicality of professional innovation,assisting engineering education reform,and promoting high-quality development of new engineering professionals cultivation.
基金funded by the National Natural Science Foundation of China,Grant Number:52175006.
文摘This article introduces a cable-driven lower limb rehabilitation robot with movable distal anchor points(M-CDLR).The traditional cable-driven parallel robots(CDPRs)control the moving platform by changing the length of cables,M-CDLR can also adjust the position of the distal anchor point when the moving platform moves.The M-CDLR this article proposed has gait and single-leg training modes,which correspond to the plane and space motion of the moving platform,respectively.After introducing the system structure configuration,the generalized kinematics and dynamics of M-CDLR are established.The fully constrained CDPRs can provide more stable rehabilitation training than the under-constrained one but requires more cables.Therefore,a motion planning method for the movable distal anchor point of M-CDLR is proposed to realize the theoretically fully constrained with fewer cables.Then the expected trajectory of the moving platform is obtained from the motion capture experiment,and the motion planning of M-CDLR under two training modes is simulated.The simulation results verify the effectiveness of the proposed motion planning method.This study serves as a basic theoretical study of the structure optimization and control strategy of M-CDLR.
基金financially supported by grants from Key Research and Development Projects of Zhejiang Province (2020C03071)the Construction Fund of Medical Key Disciplines of Hangzhou (OO20200485, OO20200055)。
文摘BACKGROUND:A20 may be a neuroprotective factor.Herein,we aimed to investigate whether serum A20 levels were associated with disease severity,delayed cerebral ischemia(DCI),and outcome after aneurysmal subarachnoid hemorrhage(aSAH).METHODS:In this prospective cohort study containing 112 aSAH patients and 112 controls,serum A20 levels were quantified.At 90 d poststroke,Modified Rankin Scale(MRS) scores≥3 were defined as a poor outcome.All correlations and associations were assessed using multivariate analysis.RESULTS:Compared with controls,there was a significant elevation of serum A20 levels in patients(median 123.7 pg/mL vs.25.8 pg/mL;P<0.001).Serum A20 levels were independently correlated with Hunt-Hess scores(β 9.854;95% confidence interval [95% CI] 2.481-17.227,P=0.009) and modified Fisher scores(β 10.349,95% CI 1.273-19.424,P=0.026).Independent associations were found between serum A20 levels and poor outcome(odds ratio [OR] 1.015,95%CI 1.000-1.031,P=0.047) and DCI(OR 1.018,95% CI 1.001-1.035,P=0.042).Areas under the curve for predicting poor outcome and DCI were 0.771(95% CI 0.682-0.845) and 0.777(95% CI 0.688-0.850),respectively.Serum A20 levels ≥128.15 pg/mL predicted poor outcome,with a sensitivity of 73.9% and specificity of 74.2%,and A20 levels ≥160.55 pg/mL distinguished the risk of DCI with65.5% sensitivity and 89.2% specificity.Its ability to predict poor outcome and DCI was similar to those of Hunt-Hess scores and modified Fisher scores(both P>0.05).CONCLUSION:Enhanced serum A20 levels are significantly associated with stroke severity and poor clinical outcome after aSAH,implying that serum A20 may be a potential prognostic biomarker for aSAH.
文摘Using of diffractive optical elements (DOE) in the Schupmann system offer a new way for the construction of ultra-large aperture telescope. The Fresnel Corrector, one of the DOEs, is the key device in the Schupmann system, which is used to correct the chromatic aberration introduced by the diffractive primary lens called Magnifying Glass. Generally, in a large aperture telescope (>20 m), the Fresnel Corrector is a diffractive lens with a large aperture and a small f-number, which is difficult to process. In this article, an improved device with a small F number but a large rim feature size, called amplitude and phase hybrid modulation Fresnel diffractive optical element (APHMFDOE), is used here as the Fresnel corrector. First, APHMFDOE with appropriate parameters is designed to match the dispersion of the Magnifying Glass so that the system meets the achromatic condition. Second, the optical characteristics of this improved system are simulated and compared with those of the general system based on the conventional Fresnel corrector. Our approach introduces a new dispersion correction device, which not only can eliminate the chromatic aberration caused by Magnifying Glass, but also can reduce the processing difficulty of Fresnel Corrector.
文摘With the arrival of the intelligence era of Industry 4.0,social development has shown complex and diversified characteristics,gradually forming an innovation ecological environment constructed by vertical interaction of multi-layer innovation systems and horizontal collaboration of multiple organizations and departments,which has posed extremely challenging requirements for higher engineering education to cultivate engineering talents with comprehensive engineering qualities who can solve complex engineering problems.However,practical engineering problems may involve a complex knowledge chain of interdisciplinary and multi-disciplinary cross-coupling.Therefore,higher engineering education needs to form a new interdisciplinary and multi-disciplinary integrated engineering innovation talent training system.Based on the characteristics of the mechanical and electronic engineering major,we will reshape and reconstruct the core courses of the mechanical and electronic engineering major.Two core courses are formed:Drive and Measurement and Control I and Drive and Measurement and Control II,with information flow and energy flow as the main lines,following up with the comprehensive practical curriculum system based on the unity of knowledge and practice and ability-oriented thinking,supporting teaching objectives,promoting students’individual development,and providing guidelines for relevant curriculum reforms.
文摘According to the GFCI ranking from 2018-2020,Hong Kong fell from third to sixth,surpassing cities in other Asian countries and some inland cities in China.Hong Kong’s marginalization has intensified because of the impact of the new crown epidemic and anti-repair incidents.However,Hong Kong’s marginalization is indeed somewhat inappropriate.As far as the situation is concerned,Hong Kong still has a strong competitiveness,although it is lagging behind,but Hong Kong should think deeply about the strategy and system of“one country,two systems”,believe in the country’s strategic intention and adjust its state in time to re-exclude the public’s understanding of its marginalization.
基金supported in part by the National Natural Science Foundation of China(NSFC)(grant number 52375534,52175503,and 51975179)the National Key Research and Development Program of China(grant number 2019YFE010747)the Fundamental Research Funds for the Central Universities(JZ2024HGTG0306).
文摘Dissipative Kerr solitons in optical microcavities enable various stable states involving multi-soliton and perfect soliton crystal(PSC),leading to widespread applications.However,the triggering condition and switching dynamics of the PSC and multi-soliton states(MSs)remain unexplored,which makes it challenging to selectively trigger the PSC/MS state for distinct area.Here,we theoretically and experimentally investigate the realization and switching of multi-/single-soliton and PSC states by engineering the periodic intracavity potential field constructed by control laser in a high-Q microrod cavity.We show that,by varying the parameters of the control laser,the PSC and multi-/single-soliton states can be selectively excited,and the soliton dynamics depends on the chaotic regime.We establish a fundamental link between the PSC switching behavior with the transient chaotic regime.Using such relation,we also demonstrate the switching and dynamical phenomena involving the conversion between PSC and MS,and soliton crystal melting and recrystallization.Our work provides additional routes for manipulation of soliton temporal and spectral profiles in optical microcavity systems and enables soliton generation on demand with desired states inside a single device.
基金funded by National Key R&D Program of China(2022ZD0115703)the National Natural Science Foundation of China(32372196,42271319)Pinduoduo-China Agricultural University Research Fund(PC2023A02002).
文摘In quantitative genomic analysis of wheat plant height(PH),the average height of a few representative plants is typically used to represent the PH of the entire plot,which overlooks the variation in height among other plants.Extracting different height quantiles from canopy point clouds can address this limitation.For this purpose,low-cost UAV cross-circling oblique(CCO)imaging,combined with structure-from-motion(SfM)and multi-view stereopsis(MVS),was employed to generate precise canopy point clouds for 262 F5 recombinant inbred lines(Zhongmai 578×Jimai 22)across seven environments.Multi-level 3D-PH measurements were extracted from six height quantiles,revealing a strong correlation(mean r=0.95)between 3D-PH and field-measured PH(FM-PH)across environments.The 90%and 92%height quantiles showed the closest agreement with FM-PH compared to other quantiles.Eleven stable quantitative trait loci(QTLs)associated with multi-level 3D-PH were identified using a 50K single nucleotide polymorphism array.Among these,QPhzj.caas-3A.2(detected by 3D-PH)and QPhzj.caas-7A.1(detected by both FM-PH and 3D-PH)represented potential novel loci.KASP markers for these QTLs were developed and validated.Furthermore,within the intervals of QPhzj.caas-5A and QPhzj.caas-3B(both were detected by 3D-PH),two candidate genes associated with PH regulation were identified:TaGL3-5A and Rht5,respectively.Corresponding KASP markers for these genes were also developed and validated.This study high-lighted the advantages of 3D model and multi-level 3D-PH in elucidating the genetic basis of crop height,and provided a precise and objective basis for advancing wheat breeding programs.
基金supported by the Fundamental Research Funds for the Central Universities(Nos.JZ2023HGQA0106 and JZ2023HGTA0199)the Anhui Provincial Natural Science Foundation(No.2308085QF208)。
文摘A highly sensitive temperature sensor was developed using a thin-walled Si O2hollow microrod resonator(SHMR)to excite Lorentz resonance and Fano resonance.The SHMR has a high Q factor(3.16×10^(7))and concise resonance modes.Moreover,the SHMR has a small wall thickness,which can effectively improve the sensitivity of the temperature sensor.The experimental results show that the sensitivity reaches 24.78 pm/℃under Lorentz resonance and further improves to 31.28 pm/℃under Fano resonance.By further reducing the wall thickness of the SHMR,the sensitivity under Lorentz resonance is increased to 34.34 pm/℃.The sensor in this study has the advantages of low cost,simple structure,high sensitivity,and satisfactory repeatability.
基金supported by the National Key Research and Development Program of China(No.2023YFA1608602)the joint Funding from the National Synchrotron Radiation Laboratory(No.KY2090000080)+1 种基金the China Postdoctoral Science Foundation(No.2024M753120)the Fundamental Research Funds for the Central Universities(No.WK2310000126)。
文摘Two-photon polymerization lithography is a technique that provides hundreds of nanometer resolution and full geometric freedom.Several X-ray polymer refractive lenses created by this technique were characterized using differential phase contrast imaging(DPCI)with a microfocus X-ray grating interferometer.The beam deflection angle and wavefront phase shift of the X-ray beam through the lens were obtained.Comparative tests using synchrotron radiation sources showed that the system could measure the surface shape of X-ray refractive lenses with an accuracy of 0.4μm.This study is important for improving the fabrication process and focusing performance of X-ray refractive lenses.
基金supported by the National Natural Science Foundation of China (Nos. 61775209, 61801129, 41871229, and 61275011)
文摘In this Letter, we demonstrate high-quality(Q), millimeter-size, and V-shaped calcium fluoride crystalline resonators for modal modification. To manufacture such resonators, we develop a home-made machining system and explore a detailed process. With a dedicated polished container, three special polishing steps, including grinding, smoothing, and polishing, are employed to achieve the required surface smoothness, which is characterized by less than 3 nm. An ultra-high-Q factor exceeding 108 is obtained by a coupled tapered fiber.In addition, a customized packaged structure for our disk resonator is achieved. The Q maintenance and stable spectrum are realized by sealing the coupling system in a hard disk. The simple, stable, portable, controlled, and integratable device would provide great potential in optical filters, sensors, nonlinear optics, cavity quantum electrodynamics, and especially some applications that require large resonators such as gyroscopes.
基金National Natural Science Foundation of China(62005071)Natural Science Foundation of Anhui Province(2008085QF312)+1 种基金Fundamental Research Funds for the Central Universities(JZ2019HGBZ0122,JZ2019H GTA0050)National Key Research and Development Program of China(2019YFE010747)。
文摘We report a broadband two-dimensional(2 D) Kerr and Raman–Kerr frequency comb generation in a silica bottle resonator accounting for azimuthal and axial degrees of freedom and pioneer a method that allows for controlled and reversible switching between a four wave mixing(FWM) state and a stimulated Raman scattering state. The repetition rate of the Raman–Kerr comb is not an integer number of the free spectral range, which spans more than 242 nm with hundreds of teeth. We show that, experimentally and numerically, multiple 2 D comb regimes can be selectively accessed via dispersion engineering by exciting different orders of axial modes or modifying the curvature of the axial profile, involving cascaded FWM, Raman lasing, and Raman-assisted FWM. The effect of axial curvature on dispersion is associated with the axial mode number in bottle resonators. Our approach enables dispersion and spectral engineering flexibility in any resonator with localized axial modes.
基金National Natural Science Foundation of China(61635013)Natural Science Basic Research Program of Shaanxi Province(2022JC-43)。
文摘Microresonator-based optical frequency combs are broadband light sources consisting of equally spaced and coherent narrow lines,which are extremely promising for applications in molecular spectroscopy and sensing in the mid-infrared(MIR)spectral region.There are still great challenges in exploring how to improve materials for microresonator fabrication,extend spectral bandwidth of parametric combs,and realize fully stabilized soliton MIR frequency combs.Here,we present an effective scheme for broadband MIR optical frequency comb generation in a MgF_(2) crystalline microresonator pumped by the quantum cascade laser.The spectral evolution dynamics of the MIR Kerr frequency comb is numerically investigated,revealing the formation mechanism of the microresonator soliton comb via scanning the pump-resonance detuning.We also experimentally implement the modulation instability state MIR frequency comb generation in MgF_(2) resonators covering from 3380 nm to 7760 nm.This work proceeds microresonator-based comb technology toward a miniaturization MIR spectroscopic device that provides potential opportunities in many fields such as fundamental physics and metrology.
