During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a rest...During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.展开更多
Nano-scale chemical inhomogeneity in surface oxide films formed on a V-and N-containing martensite stainless steel and tempering heating induced changes are investigated by a combination of synchrotron-based hard X-ra...Nano-scale chemical inhomogeneity in surface oxide films formed on a V-and N-containing martensite stainless steel and tempering heating induced changes are investigated by a combination of synchrotron-based hard X-ray Photoelectron emission spectroscopy(HAXPES)and microscopy(HAXPEEM)as well as microscopic X-ray absorption spectroscopy(μ-XAS)techniques.The results reveal the inhomogeneity in the oxide films on the micron-sized Cr_(2)N-and VN-type particles,while the inhomogeneity on the martensite matrix phase exists due to localised formation of nano-sized tempering nitride particles at 600℃.The oxide film formed on Cr_(2)N-type particles is rich in Cr_(2)O_(3) compared with that on the martensite matrix and VN-type particles.With the increase of tempering temperature,Cr_(2)O_(3) formation is faster for the oxidation of Cr in the martensite matrix than the oxidation of Cr nitride-rich particles.展开更多
In comparison with conventional experimental teaching methods,the implementation of the Motic digital microscope mutual system in the experimental teaching of medicinal botany has been demonstrated to be a highly effi...In comparison with conventional experimental teaching methods,the implementation of the Motic digital microscope mutual system in the experimental teaching of medicinal botany has been demonstrated to be a highly efficacious approach to enhance the teaching level of experimental courses in medicinal botany.The implementation of a digital microscope mutual system in experimental teaching not only enhances students practical skills in laboratory operations but also increases classroom efficiency.Furthermore,it supports personalized development among students while fostering innovative thinking,independent learning capabilities,and analysis and problem-solving skills.Additionally,this approach contributes to the enhancement of students scientific literacy.展开更多
[Objectives] To identify Pyrostegia venusta (Ker-Gawler.) Miers by microscope and ultraviolet spectrum. [Methods] The paraffin section, slide section and freehand section were used to make the cross section of the ste...[Objectives] To identify Pyrostegia venusta (Ker-Gawler.) Miers by microscope and ultraviolet spectrum. [Methods] The paraffin section, slide section and freehand section were used to make the cross section of the stem and leaf, and the surface of the leaf and the powder of the root, stem and leaf were made by the conventional method, which were observed under the optical microscope. Ultraviolet-visible spectrum identification was carried out according to a conventional method. [Results] The microscopic identification and ultraviolet-visible absorption characteristics of P. venusta (Ker-Gawler) Miers were described in detail. [Conclusions] This study is expected to provide a reference for the identification of P. venusta(KerGawler)Miers and the establishment of the related quality standard.展开更多
To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1...To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1 steels)were used to carry out the differential scanning colorimetry(DSC)and high-temperature confocal laser scanning microscope(HT-CLSM)experiments.Based on the results of DSC experiments,the equilibrium solidification process as well as the relationship among the critical undercooling degree(△T_(c)^(DSC)),latent heat of fusion/crystallization(△H_(f)/△H_(c)),equiaxed grain ratio(ER),and average grain size(△_(ave)^(ingot))was revealed.ER is increased with the decreasing△T_(c)^(DSC)and increasing△H_(f)/△H_(c);however,△_(ave)^(ingot)is decreased with them.Referring to the results of HT-CLSM experiments,the average sizes of micro-/macrostructures(d_(ave)/D_(ave)/)are decreased with the increasing cooling rate,as well as the difference between and apparent critical undercooling degree(△T_(c)^(CLSM))was revealed.The heterogeneous nucleation of the crystal nuclei occurs only if△T_(c)^(CLSM)>△T_(c)^(DSC).Combining with the interfacial wetting-lattice mismatch heterogeneous nucleation model,the dynamic mechanism of the metallic solidification was revealed.The as-cast grains of the melt-treated samples were obviously refined,owing to the much higher actual heterogeneous nucleation rates(I_(heter.,i))obtained through melt treatments,and the heterogeneous nucleation rates(I_(heter.,ij))for all samples are increased with the cooling rates,firmly confirming that the as-cast grains of each sample could be refined by the increasing cooling rates.展开更多
The infinite-layer nickelates,proposed as analogs to superconducting cuprates,provide a promising platform for exploring the mechanisms of unconventional superconductivity.However,the superconductivity has been exclus...The infinite-layer nickelates,proposed as analogs to superconducting cuprates,provide a promising platform for exploring the mechanisms of unconventional superconductivity.However,the superconductivity has been exclusively observed in thin films under atmospheric pressure,underscoring the critical role of the heterointerface.展开更多
The Savitzky-Golay(SG)filter,which employs polynomial least-squares approximations to smooth data and estimate derivatives,is widely used for processing noisy data.However,noise suppression by the SG filter is recogni...The Savitzky-Golay(SG)filter,which employs polynomial least-squares approximations to smooth data and estimate derivatives,is widely used for processing noisy data.However,noise suppression by the SG filter is recognized to be limited at data boundaries and high frequencies,which can significantly reduce the signal-to-noise ratio(SNR).To solve this problem,a novel method synergistically integrating Principal Component Analysis(PCA)with SG filtering is proposed in this paper.This approach avoids the is-sue of excessive smoothing associated with larger window sizes.The proposed PCA-SG filtering algorithm was applied to a CO gas sensing system based on Cavity Ring-Down Spectroscopy(CRDS).The perform-ance of the PCA-SG filtering algorithm is demonstrated through comparison with Moving Average Filtering(MAF),Wavelet Transformation(WT),Kalman Filtering(KF),and the SG filter.The results demonstrate that the proposed algorithm exhibits superior noise reduction capabilities compared to the other algorithms evaluated.The SNR of the ring-down signal was improved from 11.8612 dB to 29.0913 dB,and the stand-ard deviation of the extracted ring-down time constant was reduced from 0.037μs to 0.018μs.These results confirm that the proposed PCA-SG filtering algorithm effectively improves the smoothness of the ring-down curve data,demonstrating its feasibility.展开更多
Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements hav...Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements have driven electrochem-ists to develop efficient ORR catalysts using abundant materials,particularly iron(Fe)-based,known for their exceptional performance in ORR.While the crucial function of Fe in boosting ORR catalytic activity is recognized,the connection between material attributes and catalytic performance remains enigmatic.Understanding the dynamic processes involved in oxygen electrocatalysis is paramount for designing precious-metals-free ORR electrocatalysts.Mössbauer spectroscopy stands out as a powerful technique for deciphering the structural characteristics of Fe species in catalysis,facilitating the identification of active sites and the clarification of catalytic mechanisms.By showcasing noteworthy case studies within this review,we demonstrate the application of in-situ/operando 57Fe Mössbauer spectroscopy across diverse Fe-involved materials in ORR catalysis.This sheds light on various aspects of ORR catalysis,such as identifying active sites,assessing stability,and understanding the reaction mechanism.Our inquiry drives towards the opportunities and hurdles associ-ated with Mössbauer spectroscopy,unveiling potential breakthroughs and avenues for enhancement within this pivotal research realm.展开更多
Cells interact with the extracellular matrix and generate traction forces,which play fundamental roles in many cytological activities,such as migration and differentiation.The quanti fication of these traction forces ...Cells interact with the extracellular matrix and generate traction forces,which play fundamental roles in many cytological activities,such as migration and differentiation.The quanti fication of these traction forces is a prerequisite for understanding the interaction and regulation between force and functions,which can be accomplished by traction force microscopy(TFM).In TFM,the forces are determined by tracking the displacement of fiducial markers through optical microscopy.The type of fiducial marker,microscopy modality,and image processing algorithms are key factors determining the final resolution of TFM.This review summarizes efforts in three aspects to enhance the performance of TFM and discusses the challenges of further development,particularly from an optical view.展开更多
This paper describes the design and performance of the tender energy spectroscopy beamline(BL16U1),a phase Ⅱ beamline,at the Shanghai Synchrotron Radiation Facility.The beamline,based on an in-vacuum undulator source...This paper describes the design and performance of the tender energy spectroscopy beamline(BL16U1),a phase Ⅱ beamline,at the Shanghai Synchrotron Radiation Facility.The beamline,based on an in-vacuum undulator source with 26 mm period,provides an operable energy range between 2.1 keV and 16 keV,covering the K-edges of P to Rb and L3-edges of Zr to Bi.The principal optical elements of the beamline are a toroidal mirror,a liquid nitrogen-cooled double-crystal monochromator,a high-harmonic-rejection mirror,and two pairs of Kirkpatrick–Baez(KB)mirrors.Three end-stations,including non-focusing,microprobe,and sub-microprobe types,are installed on the beamline.X-ray fluorescence(XRF)and X-ray absorption spectroscopy(XAS),including X-ray absorption near-edge structure(XANES)and extended X-ray absorption fine structure(EXAFS),are performed under vacuum or He atmosphere at the non-focusing end-station(with a beam spot size of∼670μm×710μm).Using two KB mirrors systems,micro-XRF(μXRF)mapping and micro-XANES(μXANES)studies can be performed with a spot size of approximately∼3.3μm×1.3μm at the microprobe end-station and with a smaller spot size of∼0.5μm×0.25μm at the sub-microprobe end-station.The non-focusing end-station was officially opened to users in January 2024.The microprobe and sub-microprobe end-stations will be opened to users in the near future.This paper presents the characteristics,short-term technical developments,and early experimental results of this new beamline.展开更多
To address the issues of short setting time and high bleeding rate of A component,which easily cause pipe plugging and poor grouting performance when a two-component grout is injected synchronously behind the Segmenta...To address the issues of short setting time and high bleeding rate of A component,which easily cause pipe plugging and poor grouting performance when a two-component grout is injected synchronously behind the Segmental Lining,the inorganic retarder sodium pyrophosphate(TSPP)and three organic retarders were added to the A component:sodium citrate(SC),sodium tartrate(ST)and glycerol(GLY).The effect law and microscopic mechanism of viscosity,bleeding rate,setting time,gelling time,compressive strength,and stone rate were investigated.The results revealed that the addition of retarders could enhance the stability and setting time of the A component and increase the gelling time,stone rate,and compressive strength of two-component grout.Among them,the performance of the grout with an SC dosage of 0.1% was superior.The bleeding rate of this grout was reduced to 3.5%,the stone rate of the two-component grout was more than 99%,and the early compressive strength and late compressive strength of this grout were increased by approximately 35% and 7%,respectively.The initial and final setting time of the A component with a TSPP dosage of 0.3% was the longest,which was prolonged to 17 and 26 h,respectively.Microscopic analysis revealed that the four retarders hindered the hydration process of cement through complexation and adsorption,and inhibited the hydration of C_(3)S and the crystallisation of CH.Moreover,they reduced the defects caused by the rapid reaction of water glass and CH on the solid phase structure,enabled the microstructure of the stone body to be denser,and subsequently,enhanced the compressive strength.展开更多
The formation of copper deposits is closely related to hydrothermal processes.Understanding the migration of copper in hydrothermal fluids aids in reconstructing mineralization processes and deciphering deposit genesi...The formation of copper deposits is closely related to hydrothermal processes.Understanding the migration of copper in hydrothermal fluids aids in reconstructing mineralization processes and deciphering deposit genesis.Copper primarily exists as Cu^(+)and Cu^(2+)in hydrothermal solutions,with redox conditions governing their interconversion.In chloride-rich geological fluids,Cu-Cl complexes are considered critical for copper transport.However,the specific types and valence transitions of Cu-Cl complexes under varying hydrothermal conditions remain poorly understood.This study employed in situ Raman spectroscopy to systematically analyze Cu+HCl and CuCl_(2)+K_(2)S_(2)O_(3)/H_(2) systems under saturated vapor pressure at 25-300℃,elucidating the effects of temperature,Cl^(-)concentration,and redox conditions on copper speciation.In the Cu^(+)HCl system,copper dissolved as monovalent Cu-Cl complexes.At high temperatures(>200℃),[CuCl_(2)]^(-)is the dominated species,whereas[CuCl_(3)]^(2-)becomes prevalent at lower temperatures and higher HCl concentrations.For the Cu^(2+)-Cl system,the dominant species transitioned from[Cu(H_(2)O)n]^(2+)(<50℃)to[CuCl_(4)]^(2-)(100℃)and further to[CuCl]^(+)and[CuCl_(2)]^(0) at 300℃.The introduction of reducing agents(K_(2)S_(2)O_(3)/H_(2))facilitated Cu^(2+)→Cu^(+)reduction,thereby stabilizing Cu^(+)-Cl complexes and inducing partial copper precipitation.The behavior of copper in chloriderich hydrothermal fluids observed in this study indicates that high-temperature oxidizing fluids facilitate Cu mobilization,while cooling and redox changes promote deposition and ore minerals formation.展开更多
The spatially-resolved laser-based high resolution angle resolved photoemission spectroscopy(ARPES)measurements have been performed on the optimally-doped HgBa_(2)Ca_(2)Cu_(3)O_(8+δ)(Hg1223)superconductor with a T_(c...The spatially-resolved laser-based high resolution angle resolved photoemission spectroscopy(ARPES)measurements have been performed on the optimally-doped HgBa_(2)Ca_(2)Cu_(3)O_(8+δ)(Hg1223)superconductor with a T_(c) of 133 K.Two distinct regions are identified on the cleaved surface:the single Fermi surface region where only one Fermi surface is observed,and the double Fermi surface region where two Fermi surface sheets are resolved coming from both the inner(IP)and outer(OP)CuO_(2) planes.The electronic structure and superconducting gap are measured on both of these two regions.In both cases,the observed electronic states are mainly concentrated near the nodal region.The momentum dependence of the superconducting gap deviates from the standard d-wave form.These results indicate that the surface electronic structure of Hg1223 behaves more like that of underdoped cuprates.展开更多
[Objectives]This study was conducted to achieve rapid and accurate detection of protein content in rice with a particle size of 1.0 mm.[Methods]A multi-model fusion strategy was proposed on the basis of Stacking ensem...[Objectives]This study was conducted to achieve rapid and accurate detection of protein content in rice with a particle size of 1.0 mm.[Methods]A multi-model fusion strategy was proposed on the basis of Stacking ensemble learning.A base learner pool was constructed,containing Partial Least Squares(PLS),Support Vector Machine(SVM),Deep Extreme Learning Machine(DELM),Random Forest(RF),Gradient Boosting Decision Tree(GBDT),and Multilayer Perceptron(MLP).PLS,DELM,and Linear Regression(LR)were used as meta-learner candidates.Employing integer coding technology,systematic dynamic combinations of base learners and meta-learners were generated,resulting in a total of 40 non-repetitive fusion models.The optimal combination was selected through a comprehensive evaluation based on multiple assessment indicators.[Results]The combination"PLS-DELM-MLP-LR"(code 1367)achieved coefficients of determination of 0.9732 and 0.9780 on the validation set and independent test set,respectively,with relative root mean square errors of 2.35%and 2.36%,and residual predictive deviations of 6.1075 and 6.7479,respectively.[Conclusions]The Stacking fusion model significantly enhances the predictive accuracy and robustness of spectral quantitative analysis,providing an efficient and feasible solution for modeling complex agricultural product spectral data.展开更多
A RadioFrequency Quadrupole(RFQ)cooler-buncher system was developed and implemented in a collinear laser spectroscopy setup.This system converts a continuous ion beam into short bunches while enhancing the beam qualit...A RadioFrequency Quadrupole(RFQ)cooler-buncher system was developed and implemented in a collinear laser spectroscopy setup.This system converts a continuous ion beam into short bunches while enhancing the beam quality and reducing the energy spread.The functionality of the RFQ cooler buncher was verified through offline tests with stable rubidium and indium beams delivered from a surface ion source and a laser ablation ion source,respectively.Bunched ion beams with a full width at half maximum of approximately 2μs in the time-of-flight spectrum were successfully achieved with a transmission efficiency exceeding 60%.The implementation of the RFQ cooler-buncher system also significantly improved the overall transmission efficiency of the collinear laser spectroscopy setup.展开更多
The pseudo-two-dimensional(P2D)model plays an important role in exploring physicochemical mechanisms,predicting the state of health,and improving the fast charge capability for Li-ion batteries(LIBs).However,the fast ...The pseudo-two-dimensional(P2D)model plays an important role in exploring physicochemical mechanisms,predicting the state of health,and improving the fast charge capability for Li-ion batteries(LIBs).However,the fast charge leads to the lithium concentration gradient in the solid and electrolyte phases and the non-uniform electrochemical reaction at the solid/electrolyte interface.In order to decouple charge transfer reactions in LIBs under dynamic conditions,understanding the spatio-temporal resolution of the P2D model is urgently required.Till now,the study of this aspect is still insufficient.This work studies the spatio-temporal resolution for dynamic/static electrochemical impedance spectroscopy(DEIS/SEIS)on multiple scales.In detail,DEIS and SEIS with spatio-temporal resolutions are used to decouple charge transfer reactions in LIBs based on the numerical solution of the P2D model in the frequency domain.The calculated results indicate that decoupling solid diffusion requires a high spatial resolution along the r-direction in particles,decoupling electrolyte diffusion and interfacial transfer reaction requires a high spatial resolution along the x-direction,and decoupling charge transfer reactions in LIBs at an extremely low state of charge(SOC)requires an extremely high temporal resolution along the t-direction.Finally,the optimal range of spatio-temporal resolutions for DEIS/SEIS is derived,and the method to decouple charge transfer reactions with spatio-temporal resolutions is developed.展开更多
This study investigated the heterogeneous responses of organic matter(OM)in highly-to over-mature source rocks during thermal maturation.An integrated analysis was conducted on the Raman spectroscopic and geochemical ...This study investigated the heterogeneous responses of organic matter(OM)in highly-to over-mature source rocks during thermal maturation.An integrated analysis was conducted on the Raman spectroscopic and geochemical signatures of shales from the Lower Silurian Longmaxi Formation and the Lower Cambrian Qiongzhusi Formation,as well as anthracites from the Lower Permian Shanxi–Formation and the Upper Carboniferous Taiyuan Formation(collectively referred to as the Shanxi Taiyuan Formations).Additionally,burial and thermal evolution modeling was employed to support the analysis.A systematic assessment of Raman spectral parameters(e.g.,the positions and intensity ratio of the D and G bands)revealed robust correlations between the thermal history patterns of source rocks and molecular structural evolution parameters.The subsequent mechanistic quantification demonstrated that the maturation state of the source rocks was subjected to the hierarchical control of three principal factors:Peak heating temperature,the duration of sustained thermal intensity,and effective maturation duration.In addition,comparative analyses demonstrated that the anthracites attained higher structural ordering under sustained thermal conditions.This contrasts with the disordered carbon matrices observed in the intermittently heated shales.Raman spectroscopy further revealed broader variations in the D and G band intensities of the Longmaxi Formation compared to the Qiongzhusi Formation.This difference is associated with their different thermal histories.The thermal burial histories confirm that shales in the Longmaxi Formation underwent thermal exposure at lower peak temperatures over a shorter duration compared to those in the Qiongzhusi Formation.Finally,this study established a maturity calibration model for over-mature source rocks through a systematic correlation between Raman peak height ratios(R_(D/G))and vitrinite reflectance(R_(o)).展开更多
Many spore-forming Bacillus species can cause serious human diseases,because of accidental Bacillusspore infection.Thus,developing an identification strategy with both high sensitivity and specificity is greatly in de...Many spore-forming Bacillus species can cause serious human diseases,because of accidental Bacillusspore infection.Thus,developing an identification strategy with both high sensitivity and specificity is greatly in demand.In this work,we proposed a novel approach named multi-head self-attention mechanism-guided neural network Raman platform to identify living Bacillus spores within a single-cell resolution.The multi-head self-attention mechanism-guided neural network Raman platform was created by combining single-cell Raman spectroscopy,convolutional neural network(CNN),and multi-head self-attention mechanism.To address the limited size of the original spectra dataset,Gaussian noise-based spectra augmentation was employed to increase the number of single-cell Raman spectra datasets for CNN training.Owing to the assistance of both spectra augmentation and multi-head self-attention mechanism,the obtained prediction accuracy of five Bacillus spore species was further improved from 92.29±0.82%to 99.43±0.15%.To figure out the spectra differences covered by the multi-head self-attention mechanism-guided CNN,the relative classification weight from typical Raman bands was visualized via multi-head self-attention mechanism curve.In the process of spectra augmentation from 0 to 1000,the distribution of relative classification weight varied from a discrete state to a more concentrated phase.More importantly,these highlighted four Raman bands(1017,1449,1576,and 1660 cm^(-1))were assigned large weights,showing that the spectra differences in the Raman bands produced the largest contribution to prediction accuracy.It can be foreseen that,our proposed sorting platform has great potential in accurately identifying Bacillus and its related genera species at a single-cell level.展开更多
To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,...To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,Scanning Electron Microscopy(SEM),and Nuclear Magnetic Resonance(NMR)experiments were conducted.The mechanical property degradation laws and evolution characteristics of the microscopic pore structure of moraine soil under Freeze-Thaw(F-T)conditions were revealed.After F-T cycles,the stress-strain curves of moraine soil showed a strain-softening trend.In the early stage of F-T cycles(0–5 cycles),the shear strength and elastic modulus exhibited damage rate of approximately 10.33%±0.8%and 16.60%±1.2%,respectively.In the later stage(10–20 cycles),the strength parameters fluctuated slightly and tended to stabilize.The number of F-T cycles was negatively exponentially correlated with cohesion,while showing only slight fluctuation in the internal friction angle,thereby extending the Mohr-Coulomb strength criterion for moraine soil under F-T cycles.The NMR experiments quantitatively characterized the evolution of the internal pore structure of moraine soil under F-T cycles.As the number of F-T cycles increased,fine and micro pores gradually expanded and merged due to the frost-heaving effect during the water-ice phase transition,forming larger pores.The proportion of large and medium pores increased to 59.55%±2.1%(N=20),while that of fine and micro pores decreased to 40.45%±2.1%(N=20).The evolution of pore structure characteristics was essentially completed in the later stage of F-T cycles(10–20 cycles).This study provides a theoretical foundation and technical support for major engineering construction and disaster prevention in the Qinghai-Xizang Plateau.展开更多
[Objective] The research aimed to provide reference for classification of pomegranate cultivars and studies of genetic relationship among pomegranate cultivars.[Method] The electron microscope scanning was used to com...[Objective] The research aimed to provide reference for classification of pomegranate cultivars and studies of genetic relationship among pomegranate cultivars.[Method] The electron microscope scanning was used to comparatively observe leaf epidermal structures of 4 pomegranate cultivars.[Result] The upper epidermal structures of 4 pomegranate cultivars were similar and showed reticular structure .However, the differences existed in lower epidermis,such as cell shape,cell size and arrangement mode of cell as well as stomatal density,while the structures of leaf vein in lower epidermis of 4 pomegranate cultivars were similar.[Conclusion] The research provided morphological references for studying heterosis of pomegranate to some extent.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52274315 and 52374320)the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-22-011A1 and FRF-DF22-16)。
文摘During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.
基金supported by the Vinnova(project number 2020-03778)supported by the Swedish Research Council(Vetenskapsradet,project number 2021-04157).
文摘Nano-scale chemical inhomogeneity in surface oxide films formed on a V-and N-containing martensite stainless steel and tempering heating induced changes are investigated by a combination of synchrotron-based hard X-ray Photoelectron emission spectroscopy(HAXPES)and microscopy(HAXPEEM)as well as microscopic X-ray absorption spectroscopy(μ-XAS)techniques.The results reveal the inhomogeneity in the oxide films on the micron-sized Cr_(2)N-and VN-type particles,while the inhomogeneity on the martensite matrix phase exists due to localised formation of nano-sized tempering nitride particles at 600℃.The oxide film formed on Cr_(2)N-type particles is rich in Cr_(2)O_(3) compared with that on the martensite matrix and VN-type particles.With the increase of tempering temperature,Cr_(2)O_(3) formation is faster for the oxidation of Cr in the martensite matrix than the oxidation of Cr nitride-rich particles.
基金Supported by Major Project of School-level Teaching Reform and Research of Guangxi University of Chinese Medicine(2022A006)。
文摘In comparison with conventional experimental teaching methods,the implementation of the Motic digital microscope mutual system in the experimental teaching of medicinal botany has been demonstrated to be a highly efficacious approach to enhance the teaching level of experimental courses in medicinal botany.The implementation of a digital microscope mutual system in experimental teaching not only enhances students practical skills in laboratory operations but also increases classroom efficiency.Furthermore,it supports personalized development among students while fostering innovative thinking,independent learning capabilities,and analysis and problem-solving skills.Additionally,this approach contributes to the enhancement of students scientific literacy.
基金Supported by Scientific Research Program of Guangxi University of Chinese Medicine(P200246).
文摘[Objectives] To identify Pyrostegia venusta (Ker-Gawler.) Miers by microscope and ultraviolet spectrum. [Methods] The paraffin section, slide section and freehand section were used to make the cross section of the stem and leaf, and the surface of the leaf and the powder of the root, stem and leaf were made by the conventional method, which were observed under the optical microscope. Ultraviolet-visible spectrum identification was carried out according to a conventional method. [Results] The microscopic identification and ultraviolet-visible absorption characteristics of P. venusta (Ker-Gawler) Miers were described in detail. [Conclusions] This study is expected to provide a reference for the identification of P. venusta(KerGawler)Miers and the establishment of the related quality standard.
基金supported by the National Natural Science Foundation of China(Grant Nos.52274339,52174321,52074186,and 52104337)Natural Science Foundation of Jiangsu Province(Grant No.BK20231317)China Baowu Low-Carbon Metallurgy Innovation Fund(Grant No.BWLCF202108).
文摘To investigate the nucleation behavior during the single-phased metallic solidification process,the commercial ultrapure ferritic stainless steels with no(Initial steel)and various melt treatments(R1,MR1,Y2,MY1,and M1 steels)were used to carry out the differential scanning colorimetry(DSC)and high-temperature confocal laser scanning microscope(HT-CLSM)experiments.Based on the results of DSC experiments,the equilibrium solidification process as well as the relationship among the critical undercooling degree(△T_(c)^(DSC)),latent heat of fusion/crystallization(△H_(f)/△H_(c)),equiaxed grain ratio(ER),and average grain size(△_(ave)^(ingot))was revealed.ER is increased with the decreasing△T_(c)^(DSC)and increasing△H_(f)/△H_(c);however,△_(ave)^(ingot)is decreased with them.Referring to the results of HT-CLSM experiments,the average sizes of micro-/macrostructures(d_(ave)/D_(ave)/)are decreased with the increasing cooling rate,as well as the difference between and apparent critical undercooling degree(△T_(c)^(CLSM))was revealed.The heterogeneous nucleation of the crystal nuclei occurs only if△T_(c)^(CLSM)>△T_(c)^(DSC).Combining with the interfacial wetting-lattice mismatch heterogeneous nucleation model,the dynamic mechanism of the metallic solidification was revealed.The as-cast grains of the melt-treated samples were obviously refined,owing to the much higher actual heterogeneous nucleation rates(I_(heter.,i))obtained through melt treatments,and the heterogeneous nucleation rates(I_(heter.,ij))for all samples are increased with the cooling rates,firmly confirming that the as-cast grains of each sample could be refined by the increasing cooling rates.
基金supported by the National Natural Science Foundation of China[52125307(to P.G.),12404192(to R.C.S),12274061(to L.Q.)]Key Research and Development Program from the Ministry of Science and Technology(2023YFA1406301)the support from the New Cornerstone Science Foundation through the XPLORER PRIZE。
文摘The infinite-layer nickelates,proposed as analogs to superconducting cuprates,provide a promising platform for exploring the mechanisms of unconventional superconductivity.However,the superconductivity has been exclusively observed in thin films under atmospheric pressure,underscoring the critical role of the heterointerface.
文摘The Savitzky-Golay(SG)filter,which employs polynomial least-squares approximations to smooth data and estimate derivatives,is widely used for processing noisy data.However,noise suppression by the SG filter is recognized to be limited at data boundaries and high frequencies,which can significantly reduce the signal-to-noise ratio(SNR).To solve this problem,a novel method synergistically integrating Principal Component Analysis(PCA)with SG filtering is proposed in this paper.This approach avoids the is-sue of excessive smoothing associated with larger window sizes.The proposed PCA-SG filtering algorithm was applied to a CO gas sensing system based on Cavity Ring-Down Spectroscopy(CRDS).The perform-ance of the PCA-SG filtering algorithm is demonstrated through comparison with Moving Average Filtering(MAF),Wavelet Transformation(WT),Kalman Filtering(KF),and the SG filter.The results demonstrate that the proposed algorithm exhibits superior noise reduction capabilities compared to the other algorithms evaluated.The SNR of the ring-down signal was improved from 11.8612 dB to 29.0913 dB,and the stand-ard deviation of the extracted ring-down time constant was reduced from 0.037μs to 0.018μs.These results confirm that the proposed PCA-SG filtering algorithm effectively improves the smoothness of the ring-down curve data,demonstrating its feasibility.
基金financially supported by the National Natural Science Foundation of China (22350410386,W2412116,22375200,U22A202175,21961142006)。
文摘Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements have driven electrochem-ists to develop efficient ORR catalysts using abundant materials,particularly iron(Fe)-based,known for their exceptional performance in ORR.While the crucial function of Fe in boosting ORR catalytic activity is recognized,the connection between material attributes and catalytic performance remains enigmatic.Understanding the dynamic processes involved in oxygen electrocatalysis is paramount for designing precious-metals-free ORR electrocatalysts.Mössbauer spectroscopy stands out as a powerful technique for deciphering the structural characteristics of Fe species in catalysis,facilitating the identification of active sites and the clarification of catalytic mechanisms.By showcasing noteworthy case studies within this review,we demonstrate the application of in-situ/operando 57Fe Mössbauer spectroscopy across diverse Fe-involved materials in ORR catalysis.This sheds light on various aspects of ORR catalysis,such as identifying active sites,assessing stability,and understanding the reaction mechanism.Our inquiry drives towards the opportunities and hurdles associ-ated with Mössbauer spectroscopy,unveiling potential breakthroughs and avenues for enhancement within this pivotal research realm.
基金supported by the Major Research Instrument Development Project of the National Natural Science Foundation of China(32527801)the National Natural Science Foundation of China(32301168)+1 种基金the Ningbo Natural Science Foundation of China(2023J351)the Yongjiang Innovative Talents Project of Ningbo City(2024A-172-G).
文摘Cells interact with the extracellular matrix and generate traction forces,which play fundamental roles in many cytological activities,such as migration and differentiation.The quanti fication of these traction forces is a prerequisite for understanding the interaction and regulation between force and functions,which can be accomplished by traction force microscopy(TFM).In TFM,the forces are determined by tracking the displacement of fiducial markers through optical microscopy.The type of fiducial marker,microscopy modality,and image processing algorithms are key factors determining the final resolution of TFM.This review summarizes efforts in three aspects to enhance the performance of TFM and discusses the challenges of further development,particularly from an optical view.
基金supported by the National Key R&D Program of China(No.2021YFA1601003)the financial support of the SSRF PhaseⅡproject.
文摘This paper describes the design and performance of the tender energy spectroscopy beamline(BL16U1),a phase Ⅱ beamline,at the Shanghai Synchrotron Radiation Facility.The beamline,based on an in-vacuum undulator source with 26 mm period,provides an operable energy range between 2.1 keV and 16 keV,covering the K-edges of P to Rb and L3-edges of Zr to Bi.The principal optical elements of the beamline are a toroidal mirror,a liquid nitrogen-cooled double-crystal monochromator,a high-harmonic-rejection mirror,and two pairs of Kirkpatrick–Baez(KB)mirrors.Three end-stations,including non-focusing,microprobe,and sub-microprobe types,are installed on the beamline.X-ray fluorescence(XRF)and X-ray absorption spectroscopy(XAS),including X-ray absorption near-edge structure(XANES)and extended X-ray absorption fine structure(EXAFS),are performed under vacuum or He atmosphere at the non-focusing end-station(with a beam spot size of∼670μm×710μm).Using two KB mirrors systems,micro-XRF(μXRF)mapping and micro-XANES(μXANES)studies can be performed with a spot size of approximately∼3.3μm×1.3μm at the microprobe end-station and with a smaller spot size of∼0.5μm×0.25μm at the sub-microprobe end-station.The non-focusing end-station was officially opened to users in January 2024.The microprobe and sub-microprobe end-stations will be opened to users in the near future.This paper presents the characteristics,short-term technical developments,and early experimental results of this new beamline.
基金Funded by the National Natural Science Foundation of China(No.52378394)the Fundamental Research Funds for the Central Universities(No.B230201037)。
文摘To address the issues of short setting time and high bleeding rate of A component,which easily cause pipe plugging and poor grouting performance when a two-component grout is injected synchronously behind the Segmental Lining,the inorganic retarder sodium pyrophosphate(TSPP)and three organic retarders were added to the A component:sodium citrate(SC),sodium tartrate(ST)and glycerol(GLY).The effect law and microscopic mechanism of viscosity,bleeding rate,setting time,gelling time,compressive strength,and stone rate were investigated.The results revealed that the addition of retarders could enhance the stability and setting time of the A component and increase the gelling time,stone rate,and compressive strength of two-component grout.Among them,the performance of the grout with an SC dosage of 0.1% was superior.The bleeding rate of this grout was reduced to 3.5%,the stone rate of the two-component grout was more than 99%,and the early compressive strength and late compressive strength of this grout were increased by approximately 35% and 7%,respectively.The initial and final setting time of the A component with a TSPP dosage of 0.3% was the longest,which was prolonged to 17 and 26 h,respectively.Microscopic analysis revealed that the four retarders hindered the hydration process of cement through complexation and adsorption,and inhibited the hydration of C_(3)S and the crystallisation of CH.Moreover,they reduced the defects caused by the rapid reaction of water glass and CH on the solid phase structure,enabled the microstructure of the stone body to be denser,and subsequently,enhanced the compressive strength.
基金jointly funded by the Strategic Priority Research Program of the Chinese Academy of Sciences(grant No.XDA0430301)the National Natural Science Foundation of China(grant Nos.42130109,41973059)。
文摘The formation of copper deposits is closely related to hydrothermal processes.Understanding the migration of copper in hydrothermal fluids aids in reconstructing mineralization processes and deciphering deposit genesis.Copper primarily exists as Cu^(+)and Cu^(2+)in hydrothermal solutions,with redox conditions governing their interconversion.In chloride-rich geological fluids,Cu-Cl complexes are considered critical for copper transport.However,the specific types and valence transitions of Cu-Cl complexes under varying hydrothermal conditions remain poorly understood.This study employed in situ Raman spectroscopy to systematically analyze Cu+HCl and CuCl_(2)+K_(2)S_(2)O_(3)/H_(2) systems under saturated vapor pressure at 25-300℃,elucidating the effects of temperature,Cl^(-)concentration,and redox conditions on copper speciation.In the Cu^(+)HCl system,copper dissolved as monovalent Cu-Cl complexes.At high temperatures(>200℃),[CuCl_(2)]^(-)is the dominated species,whereas[CuCl_(3)]^(2-)becomes prevalent at lower temperatures and higher HCl concentrations.For the Cu^(2+)-Cl system,the dominant species transitioned from[Cu(H_(2)O)n]^(2+)(<50℃)to[CuCl_(4)]^(2-)(100℃)and further to[CuCl]^(+)and[CuCl_(2)]^(0) at 300℃.The introduction of reducing agents(K_(2)S_(2)O_(3)/H_(2))facilitated Cu^(2+)→Cu^(+)reduction,thereby stabilizing Cu^(+)-Cl complexes and inducing partial copper precipitation.The behavior of copper in chloriderich hydrothermal fluids observed in this study indicates that high-temperature oxidizing fluids facilitate Cu mobilization,while cooling and redox changes promote deposition and ore minerals formation.
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFA1401800,2022YFA1604200,2022YFA1403900,2023YFA1406002,2024YFA1408301 and 2024YFA1408100)the National Natural Science Foun-dation of China(Grant Nos.12488201,12374066,12374154,12494593)+2 种基金Quantum Science and Technology-National Science and Technology Major Project(Grant No.2021ZD0301800)CAS Superconducting Research Project(Grant No.SCZX-0101)the Synergetic Extreme Condition User Facility(SECUF).
文摘The spatially-resolved laser-based high resolution angle resolved photoemission spectroscopy(ARPES)measurements have been performed on the optimally-doped HgBa_(2)Ca_(2)Cu_(3)O_(8+δ)(Hg1223)superconductor with a T_(c) of 133 K.Two distinct regions are identified on the cleaved surface:the single Fermi surface region where only one Fermi surface is observed,and the double Fermi surface region where two Fermi surface sheets are resolved coming from both the inner(IP)and outer(OP)CuO_(2) planes.The electronic structure and superconducting gap are measured on both of these two regions.In both cases,the observed electronic states are mainly concentrated near the nodal region.The momentum dependence of the superconducting gap deviates from the standard d-wave form.These results indicate that the surface electronic structure of Hg1223 behaves more like that of underdoped cuprates.
文摘[Objectives]This study was conducted to achieve rapid and accurate detection of protein content in rice with a particle size of 1.0 mm.[Methods]A multi-model fusion strategy was proposed on the basis of Stacking ensemble learning.A base learner pool was constructed,containing Partial Least Squares(PLS),Support Vector Machine(SVM),Deep Extreme Learning Machine(DELM),Random Forest(RF),Gradient Boosting Decision Tree(GBDT),and Multilayer Perceptron(MLP).PLS,DELM,and Linear Regression(LR)were used as meta-learner candidates.Employing integer coding technology,systematic dynamic combinations of base learners and meta-learners were generated,resulting in a total of 40 non-repetitive fusion models.The optimal combination was selected through a comprehensive evaluation based on multiple assessment indicators.[Results]The combination"PLS-DELM-MLP-LR"(code 1367)achieved coefficients of determination of 0.9732 and 0.9780 on the validation set and independent test set,respectively,with relative root mean square errors of 2.35%and 2.36%,and residual predictive deviations of 6.1075 and 6.7479,respectively.[Conclusions]The Stacking fusion model significantly enhances the predictive accuracy and robustness of spectral quantitative analysis,providing an efficient and feasible solution for modeling complex agricultural product spectral data.
基金supported by the National Natural Science Foundation of China(Nos.12027809,12350007)National Key R&D Program of China(Nos.2022YFA1605100,2023YFA1606403,and 2023YFE0101600)+1 种基金New Cornerstone Science Foundation through the XPLORER PRIZEfunding from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation program under grant agreement No.679038.
文摘A RadioFrequency Quadrupole(RFQ)cooler-buncher system was developed and implemented in a collinear laser spectroscopy setup.This system converts a continuous ion beam into short bunches while enhancing the beam quality and reducing the energy spread.The functionality of the RFQ cooler buncher was verified through offline tests with stable rubidium and indium beams delivered from a surface ion source and a laser ablation ion source,respectively.Bunched ion beams with a full width at half maximum of approximately 2μs in the time-of-flight spectrum were successfully achieved with a transmission efficiency exceeding 60%.The implementation of the RFQ cooler-buncher system also significantly improved the overall transmission efficiency of the collinear laser spectroscopy setup.
基金supported by the National Natural Science Foundation of China(Nos.22479092 and 22078190)。
文摘The pseudo-two-dimensional(P2D)model plays an important role in exploring physicochemical mechanisms,predicting the state of health,and improving the fast charge capability for Li-ion batteries(LIBs).However,the fast charge leads to the lithium concentration gradient in the solid and electrolyte phases and the non-uniform electrochemical reaction at the solid/electrolyte interface.In order to decouple charge transfer reactions in LIBs under dynamic conditions,understanding the spatio-temporal resolution of the P2D model is urgently required.Till now,the study of this aspect is still insufficient.This work studies the spatio-temporal resolution for dynamic/static electrochemical impedance spectroscopy(DEIS/SEIS)on multiple scales.In detail,DEIS and SEIS with spatio-temporal resolutions are used to decouple charge transfer reactions in LIBs based on the numerical solution of the P2D model in the frequency domain.The calculated results indicate that decoupling solid diffusion requires a high spatial resolution along the r-direction in particles,decoupling electrolyte diffusion and interfacial transfer reaction requires a high spatial resolution along the x-direction,and decoupling charge transfer reactions in LIBs at an extremely low state of charge(SOC)requires an extremely high temporal resolution along the t-direction.Finally,the optimal range of spatio-temporal resolutions for DEIS/SEIS is derived,and the method to decouple charge transfer reactions with spatio-temporal resolutions is developed.
基金supported by the National Natural Science Foundation of China(42362022)the Open Fund of the Shaanxi Key Laboratory of Petroleum Accumulation Geology(PAG-202406)the Open Fund of the Mine Geology and Environment Academician and Expert Workstation(2024OITYSZJGZZ-005)。
文摘This study investigated the heterogeneous responses of organic matter(OM)in highly-to over-mature source rocks during thermal maturation.An integrated analysis was conducted on the Raman spectroscopic and geochemical signatures of shales from the Lower Silurian Longmaxi Formation and the Lower Cambrian Qiongzhusi Formation,as well as anthracites from the Lower Permian Shanxi–Formation and the Upper Carboniferous Taiyuan Formation(collectively referred to as the Shanxi Taiyuan Formations).Additionally,burial and thermal evolution modeling was employed to support the analysis.A systematic assessment of Raman spectral parameters(e.g.,the positions and intensity ratio of the D and G bands)revealed robust correlations between the thermal history patterns of source rocks and molecular structural evolution parameters.The subsequent mechanistic quantification demonstrated that the maturation state of the source rocks was subjected to the hierarchical control of three principal factors:Peak heating temperature,the duration of sustained thermal intensity,and effective maturation duration.In addition,comparative analyses demonstrated that the anthracites attained higher structural ordering under sustained thermal conditions.This contrasts with the disordered carbon matrices observed in the intermittently heated shales.Raman spectroscopy further revealed broader variations in the D and G band intensities of the Longmaxi Formation compared to the Qiongzhusi Formation.This difference is associated with their different thermal histories.The thermal burial histories confirm that shales in the Longmaxi Formation underwent thermal exposure at lower peak temperatures over a shorter duration compared to those in the Qiongzhusi Formation.Finally,this study established a maturity calibration model for over-mature source rocks through a systematic correlation between Raman peak height ratios(R_(D/G))and vitrinite reflectance(R_(o)).
基金partially supported by the National Natural Science Foundation of China(62075137)the Guangdong Basic and Applied Basic Research Foundation(2023A1515140161)+3 种基金the Guangxi Natural Science Foundation of China(2021JJB 110003)the Dongguan Science and Technology of Social Development Program(20231800936312)the high-level talent program of Dongguan University of Technology(No.221110080)the Sanming Project of Medicine in Shenzhen(No.SZSM202103014).
文摘Many spore-forming Bacillus species can cause serious human diseases,because of accidental Bacillusspore infection.Thus,developing an identification strategy with both high sensitivity and specificity is greatly in demand.In this work,we proposed a novel approach named multi-head self-attention mechanism-guided neural network Raman platform to identify living Bacillus spores within a single-cell resolution.The multi-head self-attention mechanism-guided neural network Raman platform was created by combining single-cell Raman spectroscopy,convolutional neural network(CNN),and multi-head self-attention mechanism.To address the limited size of the original spectra dataset,Gaussian noise-based spectra augmentation was employed to increase the number of single-cell Raman spectra datasets for CNN training.Owing to the assistance of both spectra augmentation and multi-head self-attention mechanism,the obtained prediction accuracy of five Bacillus spore species was further improved from 92.29±0.82%to 99.43±0.15%.To figure out the spectra differences covered by the multi-head self-attention mechanism-guided CNN,the relative classification weight from typical Raman bands was visualized via multi-head self-attention mechanism curve.In the process of spectra augmentation from 0 to 1000,the distribution of relative classification weight varied from a discrete state to a more concentrated phase.More importantly,these highlighted four Raman bands(1017,1449,1576,and 1660 cm^(-1))were assigned large weights,showing that the spectra differences in the Raman bands produced the largest contribution to prediction accuracy.It can be foreseen that,our proposed sorting platform has great potential in accurately identifying Bacillus and its related genera species at a single-cell level.
基金support from the National Natural Science Foundation of China(Grant Nos.42107193,42077245)supported by the Sichuan Science and Technology Program(2025YFNH0008,2025YFNH0004)+1 种基金the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(SKLGP2023Z006)the Everest Scientific Research Program 2.0:Research on mechanism and control of glacial lake outburst chain catastrophe in Qinghai-Xizang Plateau based on man-earth coordination perspective.
文摘To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,Scanning Electron Microscopy(SEM),and Nuclear Magnetic Resonance(NMR)experiments were conducted.The mechanical property degradation laws and evolution characteristics of the microscopic pore structure of moraine soil under Freeze-Thaw(F-T)conditions were revealed.After F-T cycles,the stress-strain curves of moraine soil showed a strain-softening trend.In the early stage of F-T cycles(0–5 cycles),the shear strength and elastic modulus exhibited damage rate of approximately 10.33%±0.8%and 16.60%±1.2%,respectively.In the later stage(10–20 cycles),the strength parameters fluctuated slightly and tended to stabilize.The number of F-T cycles was negatively exponentially correlated with cohesion,while showing only slight fluctuation in the internal friction angle,thereby extending the Mohr-Coulomb strength criterion for moraine soil under F-T cycles.The NMR experiments quantitatively characterized the evolution of the internal pore structure of moraine soil under F-T cycles.As the number of F-T cycles increased,fine and micro pores gradually expanded and merged due to the frost-heaving effect during the water-ice phase transition,forming larger pores.The proportion of large and medium pores increased to 59.55%±2.1%(N=20),while that of fine and micro pores decreased to 40.45%±2.1%(N=20).The evolution of pore structure characteristics was essentially completed in the later stage of F-T cycles(10–20 cycles).This study provides a theoretical foundation and technical support for major engineering construction and disaster prevention in the Qinghai-Xizang Plateau.
文摘[Objective] The research aimed to provide reference for classification of pomegranate cultivars and studies of genetic relationship among pomegranate cultivars.[Method] The electron microscope scanning was used to comparatively observe leaf epidermal structures of 4 pomegranate cultivars.[Result] The upper epidermal structures of 4 pomegranate cultivars were similar and showed reticular structure .However, the differences existed in lower epidermis,such as cell shape,cell size and arrangement mode of cell as well as stomatal density,while the structures of leaf vein in lower epidermis of 4 pomegranate cultivars were similar.[Conclusion] The research provided morphological references for studying heterosis of pomegranate to some extent.
