This paper introduces a multi-scale morphological edge detection algorithm to extract SAR image edge which suffers seriously from noise. Combining the basic theme of morphology with that of multi-scale analysis, the a...This paper introduces a multi-scale morphological edge detection algorithm to extract SAR image edge which suffers seriously from noise. Combining the basic theme of morphology with that of multi-scale analysis, the algorithm presents the outstanding characteristics of accuracy and robustness. Comparative Experiments reveal its fine performance.展开更多
Watershed segmentation is sensitive to noises and irregular details within the image,which frequently leads to a serious over-segmentation Linear filtering before watershed segmentation can reduce over-segmentation to...Watershed segmentation is sensitive to noises and irregular details within the image,which frequently leads to a serious over-segmentation Linear filtering before watershed segmentation can reduce over-segmentation to some extent,however,it often causes the position offset of object contours.For the purpose of reducing over-segmentation to preserve the location of object contours,the watershed segmentation based on the hierarchical multi-scale modification of morphological gradient is proposed.Firstly,multi-scale morphological filtering was employed to smooth the original image.Then,the gradient image was divided into multi-levels by the volume of three-dimension topographic relief,where the lower gradient layers were further modifiedby morphological closing with larger-sized structuring-elements,and the higher layers with the smaller one.In this way,most local minimums caused by irregular details and noises can be removed,while region contour positions corresponding to the target area were largely preserved.Finally,morphological watershed algorithm was employed to implement segmentation on the modified gradient image.The experimental results show that the proposed method can greatly reduce the over-segmentation of the watershed and avoid the position offset of the object contours.展开更多
The Asiatic Dioscorea alata yam species is an important food crop, especially in Cote d＇lvoire. It has high yield and stores longer than Dioscorea cayenensis/rotundata yam and therefore fills the hunger gap created w...The Asiatic Dioscorea alata yam species is an important food crop, especially in Cote d＇lvoire. It has high yield and stores longer than Dioscorea cayenensis/rotundata yam and therefore fills the hunger gap created when other yam types arc not available. However, very little research has been done on it. Several cultivars are susceptible to pests and diseases and lack the aesthetic values of smooth skin and elegant tuber shape ofDioscorea rotundata that appeal to consumers in the market. This study therefore sought to establish the genetic variability and relationships among 35 accessions of Ghanaian Dioscorea alata together with 14 accessions introduced from International Institute of Tropical Agriculture in Nigeria. Morphological variation was studied to establish genetic relationship among 49 accessions assembled as Dioscorea alata in Ghana. Principal component analysis （PCA） indicated that the first two principal components accounted for 25.27% of total variation from accessions with PCA1 and PCA2, contributing 13.92% and 11.35%, respectively. Cluster analysis performed clearly separated the 49 accessions into three main groupings using unweighted neighbour-joining method. Morphological descriptors were able to group the accessions into distinct clusters independent of place of collection.展开更多
A new method to visualize the large-scale crystal grain morphology of organic polycrystalline films is proposed. First,optical anisotropic transmittance images of polycrystalline zinc phthalocyanine（Zn Pc） films vac...A new method to visualize the large-scale crystal grain morphology of organic polycrystalline films is proposed. First,optical anisotropic transmittance images of polycrystalline zinc phthalocyanine（Zn Pc） films vacuum deposited by weak epitaxial growth（WEG） method were acquired with polarized optical microscopy（POM）. Then morphology properties including crystal grain size, distribution, relative orientation, and crystallinity were derived from these images by fitting with a transition dipole model. At last, atomic force microscopy（AFM） imaging was carried out to confirm the fitting and serve as absolute references. This method can be readily generalized to other organic polycrystalline films, thus providing an efficient way to access the large-scale morphologic properties of organic polycrystalline films, which may prove to be useful in industry as a film quality monitoring method.展开更多
Systematic characterization of available crop varieties using morphological traits is needed to fuel breeders＇ efforts in African eggplant. Twenty-eight accessions of African eggplant from three species of Solanum ae...Systematic characterization of available crop varieties using morphological traits is needed to fuel breeders＇ efforts in African eggplant. Twenty-eight accessions of African eggplant from three species of Solanum aethiopicum （16）, Solanum macrocarpon （9） and Solanum anguivi （3） were characterized using standard morphological descriptors. The experiment was laid out in Randomized Complete Block Design （RCBD） with three replications. The results indicated distinct and wide variations between the three Solanum species studied. There were however a lot of similarities between the S. aethiopicum and S. anguivi lines. This suggests the two materials being closer to each other than they are to the S. macrocarpon.展开更多
Assessment of genetic diversity of the indigenous crop accessions is extremely important for breeders to identify potential parents in cross-breeding programs. Fourteen cowpea accessions collected from different part&...Assessment of genetic diversity of the indigenous crop accessions is extremely important for breeders to identify potential parents in cross-breeding programs. Fourteen cowpea accessions collected from different part<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> of Sudan were used for characterization at morphological and molecular levels. The seeds of the accessions were sown in the field using a randomized complete block design with three replicates. Sixteen morphological descriptors (9 qualitative and 7 quantitative) and 20 Random Amplified Polymorphic DNA (RAPD) markers were used for characterization of the accessions. The results of morphological data revealed considerable variability within and between state’s accessions. Some morphological traits revealed similarity between accessions from different states. Among the 20 RAPD markers used, 18 were polymorphic. A total of 379 polymorphic patterns were generated;polymorphic information content (PIC) ranged from 0.63 to 0.98 with an average of 0.9. The number of fragment detected ranged from 2 for OPL-11 to 51 for OPY-2 with an average of 26.06/primer and 27.07/genotype. One to five (1</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">5) unique fragments of different sizes were detected for particular accessions, which may provide a valuable resource for breeding superior cowpea cultivars in Sudan and other semi-arid zones. Genetic similarity was ranged from 0.02 to 0.47 with an average of 0.25. Highest genetic similarity was between genotypes HSD-2966 and HSD-2967 and between genotypes HSD-5131</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">and HSD-5627 and the lowest was between HSD-5131 and HSD-5861 followed by that between HSD-2976 and HSD-29130 accessions. The study recommend</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the combination of morphological and molecular data for more efficient genetic diversity assessment and management.</span></span></span>展开更多
Felids,during intense activities such as jumping and sprinting,adjust their posture by twisting and stretching their body to disperse limb impact and minimize injury.This self-stabilization mechanism has garnered sign...Felids,during intense activities such as jumping and sprinting,adjust their posture by twisting and stretching their body to disperse limb impact and minimize injury.This self-stabilization mechanism has garnered significant attention for inspiring biometric robot design.This study investigates the flexibility and cushioning characteristics of a cat’s spine,focusing on its biomechanical properties.A high-fidelity 3D model was used to test the range of motion(ROM)under six conditions,simulate dorsiflexion to analyze stress distribution.The torsional and compressive stiffness were tested by using five cat spinal specimens.the flexibility principles of the flexible cat’s spine were explained via morphological insights.Results indicate that the cat spine has the least rotational stiffness in axial rotation,followed by extension and lateral bending,with a compressive stiffness of 53.62±4.68 N/mm.Stress during dorsiflexion is evenly distributed across vertebrae.The vertebrae heights account for 90.34%of total spinal length with a mean height-to-width ratio of 1.04.Cats’spines,with more articulations and elongated vertebrae,allow for significant twisting and bending,aiding in rapid body posture adjustments and impact mitigation.These biomechanical traits could inspire the design of robots for confined rescue operations.展开更多
A sound fundamental knowledge of the agro morphological characteristics of amaranth accessions is crucial for promoting their use in food. This review aims to assess the genetic diversity within the collection to unde...A sound fundamental knowledge of the agro morphological characteristics of amaranth accessions is crucial for promoting their use in food. This review aims to assess the genetic diversity within the collection to understand the range of genetic variation. Thirty-two agromorphological parameters of Ten amaranth accessions were analyzed in Samanko conditions. Wide variability was present concerning leaf pigmentation (PigF), flower density index (IDF), seed color (CH), and Branching index (IR). Statistical analysis showed significant differences among accessions for morphological characters such as number of plants, leaf width, stem height, terminal inflorescence length of stem, axillary inflorescence length, 50% flowering and 1000 grain weight. It appears that the Axillary Inflorescence (LIA) and the Length of the Terminal Inflorescence are correlated (r = 0.82). Length of the inflorescence terminal of the stem (LITT) and the Length of the Terminal Basal Branches (LITBT) are associated (r = 0.75). Stem height presents a robust correlation (r = 0.447) with 50% flowering date. The length of the inflorescence Axillary was also highly correlated with the length of the inflorescence terminal of the stem (r = 0.904*). Ascending hierarchical classification revealed three distinct classes: C1: Madira 1, Madira 2, A2004, A2002;C2: TP5-sel, N’gourouma, Akeri, AC-NL;C3: AHTI, Akeri. “Akeri.” “TP5-sel,” and “N’gourouma” are associated with the weight of 1000 grains, the length of the terminal branches, and the shape of the terminal inflorescence. “Poly” and “AHTI” are quite similar and are associated with the parameters of the length of basal branches and length of a terminal inflorescence of the stem “Madira 1”;“Madira 2”, “A2004”, “A2002” on the correlation circle indicates that the height of the plants and the 50% flowering date. These results indicate a high possibility of genetic diversity among the amaranth accessions within the collection. The data can be exploited in future breeding programs to improve the species.展开更多
Working conditions of rolling bearings of wind turbine generators are complicated, and their vibration signals often show non-linear and non-stationary characteristics. In order to improve the efficiency of feature ex...Working conditions of rolling bearings of wind turbine generators are complicated, and their vibration signals often show non-linear and non-stationary characteristics. In order to improve the efficiency of feature extraction of wind turbine rolling bearings and to strengthen the feature information, a new structural element and an adaptive algorithm based on the peak energy are proposed,which are combined with spectral correlation analysis to form a fault diagnosis algorithm for wind turbine rolling bearings. The proposed method firstly addresses the problem of impulsive signal omissions that are prone to occur in the process of fault feature extraction of traditional structural elements and proposes a "W" structural element to capture more characteristic information. Then, the proposed method selects the scale of multi-scale mathematical morphology, aiming at the problem of multi-scale mathematical morphology scale selection and structural element expansion law. An adaptive algorithm based on peak energy is proposed to carry out morphological scale selection and structural element expansion by improving the computing efficiency and enhancing the feature extraction effect.Finally, the proposed method performs spectral correlation analysis in the frequency domain for an unknown signal of the extracted feature and identifies the fault based on the correlation coefficient. The method is verified by numerical examples using experimental rig bearing data and actual wind field acquisition data and compared with traditional triangular and flat structural elements. The experimental results show that the new structural elements can more effectively extract the pulses in the signal and reduce noise interference,and the fault-diagnosis algorithm can accurately identify the fault category and improve the reliability of the results.展开更多
This paper aims to characterise surface morphology and 3D roughness parameters of unidirectional carbon fibre reinforced plastic(UD-CFRP)milled at 0°,45°,90°,and 135°fibre orientation angles(FOAs)....This paper aims to characterise surface morphology and 3D roughness parameters of unidirectional carbon fibre reinforced plastic(UD-CFRP)milled at 0°,45°,90°,and 135°fibre orientation angles(FOAs).Side milling experiments are conducted on UD-CFRP laminates.Surface damage forms and texture direction of milled surface are analysed.Spatial frequency of defects on CFRP surface is quantitatively determined using radially averaged 2D PSD.The kinematicdynamic surface topography is reconstructed considering feed,runout and vibration,then the ideal roughness parameters,S_(a),S_(q),S_(sk),and S_(ku)are calculated and compared with the measured ones,finally the material factor-induced roughness components are quantified.Results show that CFRP surface has no regular feed marks.The frequency of fibre breakage or surface defects is greater than tooth passing frequency.FOAs sorted by their average S_(a)in descending order is135°>90°>45°>0°,where surface defects contribute 93.9%,77.1%,73.2%,72.2%of the total roughness respectively,which suggests that surface defects show a more important role than tool kinematics and vibration in formation of milled surface.The negative Skewness(Ssk<0)and high Kurtosis(S_(ku)=4.0–11.5)of milled surface signify porosity and the presence of many anomalous deep valleys in milled surface,respectively.展开更多
The features of alkali activated slag（AAS） and portland cement （PC） were observed on multi-scale,the crack and fracture sections were observed with naked eyes,and SEM and AFM were used to study the structure morph...The features of alkali activated slag（AAS） and portland cement （PC） were observed on multi-scale,the crack and fracture sections were observed with naked eyes,and SEM and AFM were used to study the structure morphology differences between PC and AAS on micrometer to nano meter scale.The experimental results indicated that the AAS paste had soil like fracture texture and it was composed of mainly C-S-H gel but lacks of crystals,and it had a very strong tendency to shrink and crack.AAS paste is much denser and more homogeneous than PC,and on the nano scale C-S-H nano particle in the AAS paste is much smaller and packs much denser than PC paste.展开更多
The pit morphology and growth kinetics of commercially pure aluminium in naturally aerated NaCl solutions were studied using an image processing method based on reflected light microscopy. In order to distinguish betw...The pit morphology and growth kinetics of commercially pure aluminium in naturally aerated NaCl solutions were studied using an image processing method based on reflected light microscopy. In order to distinguish between pits and pre-existing cavities, metallographic examination and statistical analysis were carried out before and after corrosion testing. The results show that the pit shapes and sizes are more dependent on the immersion time than the chloride concentration. Pits are predominantly hemispherical, but they undergo reasonable geometric transitions associated with increased immersion time and occur without significant depth variation. The role of chloride ions is more closely associated with the pit nucleation phenomenon.展开更多
Seismic energy decays while propagating subsurface, which may reduce the resolution of seismic data. This paper studies the method of seismic energy dispersion compensation which provides the basic principles for mult...Seismic energy decays while propagating subsurface, which may reduce the resolution of seismic data. This paper studies the method of seismic energy dispersion compensation which provides the basic principles for multi-scale morphology and the spectrum simulation method. These methods are applied in seismic energy compensation. First of all, the seismic data is decomposed into multiple scales and the effective frequency bandwidth is selectively broadened for some scales by using a spectrum simulation method. In this process, according to the amplitude spectrum of each scale, the best simulation range is selected to simulate the middle and low frequency components to ensure the authenticity of the simulation curve which is calculated by the median method, and the high frequency component is broadened. Finally, these scales are reconstructed with reasonable coefficients, and the compensated seismic data can be obtained. Examples are shown to illustrate the feasibility of the energy compensation method.展开更多
In this paper,we implement three scales of fracture integrated prediction study by classifying it to macro-（ 1/4/λ）,meso-（ 1/100λ and 1/4λ） and micro-（ 1/100λ） scales.Based on the multi-scales rock physics ...In this paper,we implement three scales of fracture integrated prediction study by classifying it to macro-（ 1/4/λ）,meso-（ 1/100λ and 1/4λ） and micro-（ 1/100λ） scales.Based on the multi-scales rock physics modelling technique,the seismic azimuthal anisotropy characteristic is analyzed for distinguishing the fractures of meso-scale.Furthermore,by integrating geological core fracture description,image well-logging fracture interpretation,seismic attributes macro-scale fracture prediction and core slice micro-scale fracture characterization,an comprehensive multi-scale fracture prediction methodology and technique workflow are proposed by using geology,well-logging and seismic multi-attributes.Firstly,utilizing the geology core slice observation（Fractures description） and image well-logging data interpretation results,the main governing factors of fracture development are obtained,and then the control factors of the development of regional macro-scale fractures are carried out via modelling of the tectonic stress field.For the meso-scale fracture description,the poststack geometric attributes are used to describe the macro-scale fracture as well,the prestack attenuation seismic attribute is used to predict the meso-scale fracture.Finally,by combining lithological statistic inversion with superposed results of faults,the relationship of the meso-scale fractures,lithology and faults can be reasonably interpreted and the cause of meso-scale fractures can be verified.The micro-scale fracture description is mainly implemented by using the electron microscope scanning of cores.Therefore,the development of fractures in reservoirs is assessed by valuating three classes of fracture prediction results.An integrated fracture prediction application to a real field in Sichuan basin,where limestone reservoir fractures developed,is implemented.The application results in the study area indicates that the proposed multi-scales integrated fracture prediction method and the technique procedureare able to deal with the strong heterogeneity and multi-scales problems in fracture prediction.Moreover,the multi-scale fracture prediction technique integrated with geology,well-logging and seismic multi-information can help improve the reservoir characterization and sweet-spots prediction for the fractured hydrocarbon reservoirs.展开更多
In this paper, we explore diamond synthesis with a series of experiments using an Fe-Ni catalyst and a P3N5 additive in the temperature range of 1250-1550 ℃ and the pressure range of 5.0-6.3 GPa. We also investigate ...In this paper, we explore diamond synthesis with a series of experiments using an Fe-Ni catalyst and a P3N5 additive in the temperature range of 1250-1550 ℃ and the pressure range of 5.0-6.3 GPa. We also investigate the influence of nitrogen on diamond crystallization. Our results show that the synthesis conditions （temperature and pressure） increase with the amount of P3N5 additive increasing. The nitrogen impurity can significantly influence the diamond morphology. The diamonds stably grow into strip and lamellar shapes in the nitrogen-rich environment. The Fourier-transform infrared spectrum shows that the nitrogen concentration increases rapidly with the content of P3N5 additive increasing. By spectrum analysis, we find that with the increase of the nitrogen concentration, the Ib-type nitrogen atoms can aggregate in the A-centre form. The highest A-centre nitrogen concentration is approximately 840 ppm.展开更多
Objective: To investigate the composition of volatile compounds in the different accessions of Perilla frutescens(P. frutescens) collected from various habitats of China and Japan. Methods: In the present study, the e...Objective: To investigate the composition of volatile compounds in the different accessions of Perilla frutescens(P. frutescens) collected from various habitats of China and Japan. Methods: In the present study, the essential oil from the leaves of P. frutescens cultivars from China and Japan was extracted by hydro-distillation and the chemical composition and concentration of the volatile components present in the oils were determined by gas chromatography–mass spectrometry(GC–MS) analysis. Results: Among the volatile components, the major proportion was of perilla ketone, which was followed by elemicin and beta-caryophyllene in the Chinese Perilla cultivars. The main component in the oil extracted from the Japanese accessions was myristicin, which was followed by perilla ketone and beta-caryophyllene. We could distinguish seven chemotypes, namely the perilla ketone(PK) type, perilla ketone, myristicin(PM) type, perilla ketone, unknown(PU) type, perilla ketone, beta-caryophyllene, myristicine(PB) type, perilla ketone, myristicin, unknown(PMU) type, perilla ketone, elemicine, myristicin, beta-caryophyllene(PEMB) type, and the perilla ketone, limonene, betacryophyllene, myristicin(L) type. Most of the accessions possessed higher essential oil content before the flowering time than at the flowering stage. The average plant height, leaf length, leaf width of the Chinese accessions was higher than those of the Japanese accessions. Conclusion:The results revealed that the harvest time and geographical origin caused polymorphisms in the essential oil composition and morphological traits in the Perilla accessions originating from China and Japan. Therefore, these chemotypes with desirable characters might be useful for industrial exploitation and for determining the harvest time.展开更多
The sheep populations were studied with Q-type Hierarchical Clustering Method, and characters of the populations were used to construct the principal component, then, the principal component values were analyzed with ...The sheep populations were studied with Q-type Hierarchical Clustering Method, and characters of the populations were used to construct the principal component, then, the principal component values were analyzed with R-type Hierarchical Clustering Method, which might display the genetic differentiation among populations and conform to the result of the known sheep phylogenetic system in China. Characters of the populations were studied with Q-type Hierarchical Clustering Method. The elevation and average annual rainfall were found to be important characters. The ecology factor is also an important character for the breed classification.展开更多
The high-frequency components in the traditional multi-scale transform method are approximately sparse, which can represent different information of the details. But in the low-frequency component, the coefficients ar...The high-frequency components in the traditional multi-scale transform method are approximately sparse, which can represent different information of the details. But in the low-frequency component, the coefficients around the zero value are very few, so we cannot sparsely represent low-frequency image information. The low-frequency component contains the main energy of the image and depicts the profile of the image. Direct fusion of the low-frequency component will not be conducive to obtain highly accurate fusion result. Therefore, this paper presents an infrared and visible image fusion method combining the multi-scale and top-hat transforms. On one hand, the new top-hat-transform can effectively extract the salient features of the low-frequency component. On the other hand, the multi-scale transform can extract highfrequency detailed information in multiple scales and from diverse directions. The combination of the two methods is conducive to the acquisition of more characteristics and more accurate fusion results. Among them, for the low-frequency component, a new type of top-hat transform is used to extract low-frequency features, and then different fusion rules are applied to fuse the low-frequency features and low-frequency background; for high-frequency components, the product of characteristics method is used to integrate the detailed information in high-frequency. Experimental results show that the proposed algorithm can obtain more detailed information and clearer infrared target fusion results than the traditional multiscale transform methods. Compared with the state-of-the-art fusion methods based on sparse representation, the proposed algorithm is simple and efficacious, and the time consumption is significantly reduced.展开更多
Quantifying surface cracks in alpine meadows is a prerequisite and a key aspect in the study of grassland crack development.Crack characterization indices are crucial for the quantitative characterization of complex c...Quantifying surface cracks in alpine meadows is a prerequisite and a key aspect in the study of grassland crack development.Crack characterization indices are crucial for the quantitative characterization of complex cracks,serving as vital factors in assessing the degree of cracking and the development morphology.So far,research on evaluating the degree of grassland degradation through crack characterization indices is rare,especially the quantitative analysis of the development of surface cracks in alpine meadows is relatively scarce.Therefore,based on the phenomenon of surface cracking during the degradation of alpine meadows in some regions of the Qinghai-Tibet Plateau,we selected the alpine meadow in the Huangcheng Mongolian Township,Menyuan Hui Autonomous County,Qinghai Province,China as the study area,used unmanned aerial vehicle(UAV)sensing technology to acquire low-altitude images of alpine meadow surface cracks at different degrees of degradation(light,medium,and heavy degradation),and analyzed the representative metrics characterizing the degree of crack development by interpreting the crack length,length density,branch angle,and burrow(rat hole)distribution density and combining them with in situ crack width and depth measurements.Finally,the correlations between the crack characterization indices and the soil and root parameters of sample plots at different degrees of degradation in the study area were analyzed using the grey relation analysis.The results revealed that with the increase of degradation,the physical and chemical properties of soil and the mechanical properties of root-soil composite changed significantly,the vegetation coverage reduced,and the root system aggregated in the surface layer of alpine meadow.As the degree of degradation increased,the fracture morphology developed from"linear"to"dendritic",and eventually to a complex and irregular"polygonal"pattern.The crack length,width,depth,and length density were identified as the crack characterization indices via analysis of variance.The results of grey relation analysis also revealed that the crack length,width,depth,and length density were all highly correlated with root length density,and as the degradation of alpine meadows intensified,the underground biomass increased dramatically,forming a dense layer of grass felt,which has a significant impact on the formation and expansion of cracks.展开更多
基金Supported the NatioIlal Naturel Science Foundation of China(No.69831040)
文摘This paper introduces a multi-scale morphological edge detection algorithm to extract SAR image edge which suffers seriously from noise. Combining the basic theme of morphology with that of multi-scale analysis, the algorithm presents the outstanding characteristics of accuracy and robustness. Comparative Experiments reveal its fine performance.
基金National Natural Science Foundation of China(No.61261029)
文摘Watershed segmentation is sensitive to noises and irregular details within the image,which frequently leads to a serious over-segmentation Linear filtering before watershed segmentation can reduce over-segmentation to some extent,however,it often causes the position offset of object contours.For the purpose of reducing over-segmentation to preserve the location of object contours,the watershed segmentation based on the hierarchical multi-scale modification of morphological gradient is proposed.Firstly,multi-scale morphological filtering was employed to smooth the original image.Then,the gradient image was divided into multi-levels by the volume of three-dimension topographic relief,where the lower gradient layers were further modifiedby morphological closing with larger-sized structuring-elements,and the higher layers with the smaller one.In this way,most local minimums caused by irregular details and noises can be removed,while region contour positions corresponding to the target area were largely preserved.Finally,morphological watershed algorithm was employed to implement segmentation on the modified gradient image.The experimental results show that the proposed method can greatly reduce the over-segmentation of the watershed and avoid the position offset of the object contours.
文摘The Asiatic Dioscorea alata yam species is an important food crop, especially in Cote d＇lvoire. It has high yield and stores longer than Dioscorea cayenensis/rotundata yam and therefore fills the hunger gap created when other yam types arc not available. However, very little research has been done on it. Several cultivars are susceptible to pests and diseases and lack the aesthetic values of smooth skin and elegant tuber shape ofDioscorea rotundata that appeal to consumers in the market. This study therefore sought to establish the genetic variability and relationships among 35 accessions of Ghanaian Dioscorea alata together with 14 accessions introduced from International Institute of Tropical Agriculture in Nigeria. Morphological variation was studied to establish genetic relationship among 49 accessions assembled as Dioscorea alata in Ghana. Principal component analysis （PCA） indicated that the first two principal components accounted for 25.27% of total variation from accessions with PCA1 and PCA2, contributing 13.92% and 11.35%, respectively. Cluster analysis performed clearly separated the 49 accessions into three main groupings using unweighted neighbour-joining method. Morphological descriptors were able to group the accessions into distinct clusters independent of place of collection.
基金Project supported by the National Natural Science Foundation of China(Grant No.20933010)the National Basic Research Program of China(Grant No.2013CB834800)
文摘A new method to visualize the large-scale crystal grain morphology of organic polycrystalline films is proposed. First,optical anisotropic transmittance images of polycrystalline zinc phthalocyanine（Zn Pc） films vacuum deposited by weak epitaxial growth（WEG） method were acquired with polarized optical microscopy（POM）. Then morphology properties including crystal grain size, distribution, relative orientation, and crystallinity were derived from these images by fitting with a transition dipole model. At last, atomic force microscopy（AFM） imaging was carried out to confirm the fitting and serve as absolute references. This method can be readily generalized to other organic polycrystalline films, thus providing an efficient way to access the large-scale morphologic properties of organic polycrystalline films, which may prove to be useful in industry as a film quality monitoring method.
文摘Systematic characterization of available crop varieties using morphological traits is needed to fuel breeders＇ efforts in African eggplant. Twenty-eight accessions of African eggplant from three species of Solanum aethiopicum （16）, Solanum macrocarpon （9） and Solanum anguivi （3） were characterized using standard morphological descriptors. The experiment was laid out in Randomized Complete Block Design （RCBD） with three replications. The results indicated distinct and wide variations between the three Solanum species studied. There were however a lot of similarities between the S. aethiopicum and S. anguivi lines. This suggests the two materials being closer to each other than they are to the S. macrocarpon.
文摘Assessment of genetic diversity of the indigenous crop accessions is extremely important for breeders to identify potential parents in cross-breeding programs. Fourteen cowpea accessions collected from different part<span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> of Sudan were used for characterization at morphological and molecular levels. The seeds of the accessions were sown in the field using a randomized complete block design with three replicates. Sixteen morphological descriptors (9 qualitative and 7 quantitative) and 20 Random Amplified Polymorphic DNA (RAPD) markers were used for characterization of the accessions. The results of morphological data revealed considerable variability within and between state’s accessions. Some morphological traits revealed similarity between accessions from different states. Among the 20 RAPD markers used, 18 were polymorphic. A total of 379 polymorphic patterns were generated;polymorphic information content (PIC) ranged from 0.63 to 0.98 with an average of 0.9. The number of fragment detected ranged from 2 for OPL-11 to 51 for OPY-2 with an average of 26.06/primer and 27.07/genotype. One to five (1</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">5) unique fragments of different sizes were detected for particular accessions, which may provide a valuable resource for breeding superior cowpea cultivars in Sudan and other semi-arid zones. Genetic similarity was ranged from 0.02 to 0.47 with an average of 0.25. Highest genetic similarity was between genotypes HSD-2966 and HSD-2967 and between genotypes HSD-5131</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">and HSD-5627 and the lowest was between HSD-5131 and HSD-5861 followed by that between HSD-2976 and HSD-29130 accessions. The study recommend</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the combination of morphological and molecular data for more efficient genetic diversity assessment and management.</span></span></span>
基金funded by the Guangdong Basic and Applied Basic Research Foundation(2023A1515110378)the National Natural Science Foundation of China(Nos.12402368).
文摘Felids,during intense activities such as jumping and sprinting,adjust their posture by twisting and stretching their body to disperse limb impact and minimize injury.This self-stabilization mechanism has garnered significant attention for inspiring biometric robot design.This study investigates the flexibility and cushioning characteristics of a cat’s spine,focusing on its biomechanical properties.A high-fidelity 3D model was used to test the range of motion(ROM)under six conditions,simulate dorsiflexion to analyze stress distribution.The torsional and compressive stiffness were tested by using five cat spinal specimens.the flexibility principles of the flexible cat’s spine were explained via morphological insights.Results indicate that the cat spine has the least rotational stiffness in axial rotation,followed by extension and lateral bending,with a compressive stiffness of 53.62±4.68 N/mm.Stress during dorsiflexion is evenly distributed across vertebrae.The vertebrae heights account for 90.34%of total spinal length with a mean height-to-width ratio of 1.04.Cats’spines,with more articulations and elongated vertebrae,allow for significant twisting and bending,aiding in rapid body posture adjustments and impact mitigation.These biomechanical traits could inspire the design of robots for confined rescue operations.
文摘A sound fundamental knowledge of the agro morphological characteristics of amaranth accessions is crucial for promoting their use in food. This review aims to assess the genetic diversity within the collection to understand the range of genetic variation. Thirty-two agromorphological parameters of Ten amaranth accessions were analyzed in Samanko conditions. Wide variability was present concerning leaf pigmentation (PigF), flower density index (IDF), seed color (CH), and Branching index (IR). Statistical analysis showed significant differences among accessions for morphological characters such as number of plants, leaf width, stem height, terminal inflorescence length of stem, axillary inflorescence length, 50% flowering and 1000 grain weight. It appears that the Axillary Inflorescence (LIA) and the Length of the Terminal Inflorescence are correlated (r = 0.82). Length of the inflorescence terminal of the stem (LITT) and the Length of the Terminal Basal Branches (LITBT) are associated (r = 0.75). Stem height presents a robust correlation (r = 0.447) with 50% flowering date. The length of the inflorescence Axillary was also highly correlated with the length of the inflorescence terminal of the stem (r = 0.904*). Ascending hierarchical classification revealed three distinct classes: C1: Madira 1, Madira 2, A2004, A2002;C2: TP5-sel, N’gourouma, Akeri, AC-NL;C3: AHTI, Akeri. “Akeri.” “TP5-sel,” and “N’gourouma” are associated with the weight of 1000 grains, the length of the terminal branches, and the shape of the terminal inflorescence. “Poly” and “AHTI” are quite similar and are associated with the parameters of the length of basal branches and length of a terminal inflorescence of the stem “Madira 1”;“Madira 2”, “A2004”, “A2002” on the correlation circle indicates that the height of the plants and the 50% flowering date. These results indicate a high possibility of genetic diversity among the amaranth accessions within the collection. The data can be exploited in future breeding programs to improve the species.
基金supported by National Natural Science Foundation of China (No. 61763037)Inner Mongolia Autonomous Region Natural Science Foundation of China(No. 2019LH06007)Science and Technology Plan Project of Inner Mongolia (No. 2019,2020GG028)。
文摘Working conditions of rolling bearings of wind turbine generators are complicated, and their vibration signals often show non-linear and non-stationary characteristics. In order to improve the efficiency of feature extraction of wind turbine rolling bearings and to strengthen the feature information, a new structural element and an adaptive algorithm based on the peak energy are proposed,which are combined with spectral correlation analysis to form a fault diagnosis algorithm for wind turbine rolling bearings. The proposed method firstly addresses the problem of impulsive signal omissions that are prone to occur in the process of fault feature extraction of traditional structural elements and proposes a "W" structural element to capture more characteristic information. Then, the proposed method selects the scale of multi-scale mathematical morphology, aiming at the problem of multi-scale mathematical morphology scale selection and structural element expansion law. An adaptive algorithm based on peak energy is proposed to carry out morphological scale selection and structural element expansion by improving the computing efficiency and enhancing the feature extraction effect.Finally, the proposed method performs spectral correlation analysis in the frequency domain for an unknown signal of the extracted feature and identifies the fault based on the correlation coefficient. The method is verified by numerical examples using experimental rig bearing data and actual wind field acquisition data and compared with traditional triangular and flat structural elements. The experimental results show that the new structural elements can more effectively extract the pulses in the signal and reduce noise interference,and the fault-diagnosis algorithm can accurately identify the fault category and improve the reliability of the results.
基金supported by the National Key R&D Program of China(No.2020YFB2010600)。
文摘This paper aims to characterise surface morphology and 3D roughness parameters of unidirectional carbon fibre reinforced plastic(UD-CFRP)milled at 0°,45°,90°,and 135°fibre orientation angles(FOAs).Side milling experiments are conducted on UD-CFRP laminates.Surface damage forms and texture direction of milled surface are analysed.Spatial frequency of defects on CFRP surface is quantitatively determined using radially averaged 2D PSD.The kinematicdynamic surface topography is reconstructed considering feed,runout and vibration,then the ideal roughness parameters,S_(a),S_(q),S_(sk),and S_(ku)are calculated and compared with the measured ones,finally the material factor-induced roughness components are quantified.Results show that CFRP surface has no regular feed marks.The frequency of fibre breakage or surface defects is greater than tooth passing frequency.FOAs sorted by their average S_(a)in descending order is135°>90°>45°>0°,where surface defects contribute 93.9%,77.1%,73.2%,72.2%of the total roughness respectively,which suggests that surface defects show a more important role than tool kinematics and vibration in formation of milled surface.The negative Skewness(Ssk<0)and high Kurtosis(S_(ku)=4.0–11.5)of milled surface signify porosity and the presence of many anomalous deep valleys in milled surface,respectively.
基金Funded by the Open Foundation of National Key Laboratory of Green Building Materials(CBM-08-KF103)
文摘The features of alkali activated slag（AAS） and portland cement （PC） were observed on multi-scale,the crack and fracture sections were observed with naked eyes,and SEM and AFM were used to study the structure morphology differences between PC and AAS on micrometer to nano meter scale.The experimental results indicated that the AAS paste had soil like fracture texture and it was composed of mainly C-S-H gel but lacks of crystals,and it had a very strong tendency to shrink and crack.AAS paste is much denser and more homogeneous than PC,and on the nano scale C-S-H nano particle in the AAS paste is much smaller and packs much denser than PC paste.
基金This research was supported by FUNDUNESP(process 01258/2008 and 00601/2011-DFP)CNPq(processes 305224/2004-2 and 307271/2007-2).
文摘The pit morphology and growth kinetics of commercially pure aluminium in naturally aerated NaCl solutions were studied using an image processing method based on reflected light microscopy. In order to distinguish between pits and pre-existing cavities, metallographic examination and statistical analysis were carried out before and after corrosion testing. The results show that the pit shapes and sizes are more dependent on the immersion time than the chloride concentration. Pits are predominantly hemispherical, but they undergo reasonable geometric transitions associated with increased immersion time and occur without significant depth variation. The role of chloride ions is more closely associated with the pit nucleation phenomenon.
文摘Seismic energy decays while propagating subsurface, which may reduce the resolution of seismic data. This paper studies the method of seismic energy dispersion compensation which provides the basic principles for multi-scale morphology and the spectrum simulation method. These methods are applied in seismic energy compensation. First of all, the seismic data is decomposed into multiple scales and the effective frequency bandwidth is selectively broadened for some scales by using a spectrum simulation method. In this process, according to the amplitude spectrum of each scale, the best simulation range is selected to simulate the middle and low frequency components to ensure the authenticity of the simulation curve which is calculated by the median method, and the high frequency component is broadened. Finally, these scales are reconstructed with reasonable coefficients, and the compensated seismic data can be obtained. Examples are shown to illustrate the feasibility of the energy compensation method.
基金supported by the national oil and gas major project(No.2011ZX05019-008)National Natural Science Foundation of China(No.41574108 and U1262208)presented at the Exploration Geophysics Symposium 2015 of the EAGE Local Chapter China
文摘In this paper,we implement three scales of fracture integrated prediction study by classifying it to macro-（ 1/4/λ）,meso-（ 1/100λ and 1/4λ） and micro-（ 1/100λ） scales.Based on the multi-scales rock physics modelling technique,the seismic azimuthal anisotropy characteristic is analyzed for distinguishing the fractures of meso-scale.Furthermore,by integrating geological core fracture description,image well-logging fracture interpretation,seismic attributes macro-scale fracture prediction and core slice micro-scale fracture characterization,an comprehensive multi-scale fracture prediction methodology and technique workflow are proposed by using geology,well-logging and seismic multi-attributes.Firstly,utilizing the geology core slice observation（Fractures description） and image well-logging data interpretation results,the main governing factors of fracture development are obtained,and then the control factors of the development of regional macro-scale fractures are carried out via modelling of the tectonic stress field.For the meso-scale fracture description,the poststack geometric attributes are used to describe the macro-scale fracture as well,the prestack attenuation seismic attribute is used to predict the meso-scale fracture.Finally,by combining lithological statistic inversion with superposed results of faults,the relationship of the meso-scale fractures,lithology and faults can be reasonably interpreted and the cause of meso-scale fractures can be verified.The micro-scale fracture description is mainly implemented by using the electron microscope scanning of cores.Therefore,the development of fractures in reservoirs is assessed by valuating three classes of fracture prediction results.An integrated fracture prediction application to a real field in Sichuan basin,where limestone reservoir fractures developed,is implemented.The application results in the study area indicates that the proposed multi-scales integrated fracture prediction method and the technique procedureare able to deal with the strong heterogeneity and multi-scales problems in fracture prediction.Moreover,the multi-scale fracture prediction technique integrated with geology,well-logging and seismic multi-information can help improve the reservoir characterization and sweet-spots prediction for the fractured hydrocarbon reservoirs.
基金Project supported by the National Natural Science Foundation of China (Grant No. 51172089)the Program for New Century Excellent Talents in University,China
文摘In this paper, we explore diamond synthesis with a series of experiments using an Fe-Ni catalyst and a P3N5 additive in the temperature range of 1250-1550 ℃ and the pressure range of 5.0-6.3 GPa. We also investigate the influence of nitrogen on diamond crystallization. Our results show that the synthesis conditions （temperature and pressure） increase with the amount of P3N5 additive increasing. The nitrogen impurity can significantly influence the diamond morphology. The diamonds stably grow into strip and lamellar shapes in the nitrogen-rich environment. The Fourier-transform infrared spectrum shows that the nitrogen concentration increases rapidly with the content of P3N5 additive increasing. By spectrum analysis, we find that with the increase of the nitrogen concentration, the Ib-type nitrogen atoms can aggregate in the A-centre form. The highest A-centre nitrogen concentration is approximately 840 ppm.
基金supported by funding from the Konkuk University Brain Pool
文摘Objective: To investigate the composition of volatile compounds in the different accessions of Perilla frutescens(P. frutescens) collected from various habitats of China and Japan. Methods: In the present study, the essential oil from the leaves of P. frutescens cultivars from China and Japan was extracted by hydro-distillation and the chemical composition and concentration of the volatile components present in the oils were determined by gas chromatography–mass spectrometry(GC–MS) analysis. Results: Among the volatile components, the major proportion was of perilla ketone, which was followed by elemicin and beta-caryophyllene in the Chinese Perilla cultivars. The main component in the oil extracted from the Japanese accessions was myristicin, which was followed by perilla ketone and beta-caryophyllene. We could distinguish seven chemotypes, namely the perilla ketone(PK) type, perilla ketone, myristicin(PM) type, perilla ketone, unknown(PU) type, perilla ketone, beta-caryophyllene, myristicine(PB) type, perilla ketone, myristicin, unknown(PMU) type, perilla ketone, elemicine, myristicin, beta-caryophyllene(PEMB) type, and the perilla ketone, limonene, betacryophyllene, myristicin(L) type. Most of the accessions possessed higher essential oil content before the flowering time than at the flowering stage. The average plant height, leaf length, leaf width of the Chinese accessions was higher than those of the Japanese accessions. Conclusion:The results revealed that the harvest time and geographical origin caused polymorphisms in the essential oil composition and morphological traits in the Perilla accessions originating from China and Japan. Therefore, these chemotypes with desirable characters might be useful for industrial exploitation and for determining the harvest time.
基金supported by International Cooperative Item of the Nationa1 Natura1 Science Foundation of China(30310103007).
文摘The sheep populations were studied with Q-type Hierarchical Clustering Method, and characters of the populations were used to construct the principal component, then, the principal component values were analyzed with R-type Hierarchical Clustering Method, which might display the genetic differentiation among populations and conform to the result of the known sheep phylogenetic system in China. Characters of the populations were studied with Q-type Hierarchical Clustering Method. The elevation and average annual rainfall were found to be important characters. The ecology factor is also an important character for the breed classification.
基金Project supported by the National Natural Science Foundation of China(Grant No.61402368)Aerospace Support Fund,China(Grant No.2017-HT-XGD)Aerospace Science and Technology Innovation Foundation,China(Grant No.2017 ZD 53047)
文摘The high-frequency components in the traditional multi-scale transform method are approximately sparse, which can represent different information of the details. But in the low-frequency component, the coefficients around the zero value are very few, so we cannot sparsely represent low-frequency image information. The low-frequency component contains the main energy of the image and depicts the profile of the image. Direct fusion of the low-frequency component will not be conducive to obtain highly accurate fusion result. Therefore, this paper presents an infrared and visible image fusion method combining the multi-scale and top-hat transforms. On one hand, the new top-hat-transform can effectively extract the salient features of the low-frequency component. On the other hand, the multi-scale transform can extract highfrequency detailed information in multiple scales and from diverse directions. The combination of the two methods is conducive to the acquisition of more characteristics and more accurate fusion results. Among them, for the low-frequency component, a new type of top-hat transform is used to extract low-frequency features, and then different fusion rules are applied to fuse the low-frequency features and low-frequency background; for high-frequency components, the product of characteristics method is used to integrate the detailed information in high-frequency. Experimental results show that the proposed algorithm can obtain more detailed information and clearer infrared target fusion results than the traditional multiscale transform methods. Compared with the state-of-the-art fusion methods based on sparse representation, the proposed algorithm is simple and efficacious, and the time consumption is significantly reduced.
基金This study was funded by the National Natural Science Foundation of China(42062019,42002283)the Project of Qinghai Science&Technology Department(2021-ZJ-927).
文摘Quantifying surface cracks in alpine meadows is a prerequisite and a key aspect in the study of grassland crack development.Crack characterization indices are crucial for the quantitative characterization of complex cracks,serving as vital factors in assessing the degree of cracking and the development morphology.So far,research on evaluating the degree of grassland degradation through crack characterization indices is rare,especially the quantitative analysis of the development of surface cracks in alpine meadows is relatively scarce.Therefore,based on the phenomenon of surface cracking during the degradation of alpine meadows in some regions of the Qinghai-Tibet Plateau,we selected the alpine meadow in the Huangcheng Mongolian Township,Menyuan Hui Autonomous County,Qinghai Province,China as the study area,used unmanned aerial vehicle(UAV)sensing technology to acquire low-altitude images of alpine meadow surface cracks at different degrees of degradation(light,medium,and heavy degradation),and analyzed the representative metrics characterizing the degree of crack development by interpreting the crack length,length density,branch angle,and burrow(rat hole)distribution density and combining them with in situ crack width and depth measurements.Finally,the correlations between the crack characterization indices and the soil and root parameters of sample plots at different degrees of degradation in the study area were analyzed using the grey relation analysis.The results revealed that with the increase of degradation,the physical and chemical properties of soil and the mechanical properties of root-soil composite changed significantly,the vegetation coverage reduced,and the root system aggregated in the surface layer of alpine meadow.As the degree of degradation increased,the fracture morphology developed from"linear"to"dendritic",and eventually to a complex and irregular"polygonal"pattern.The crack length,width,depth,and length density were identified as the crack characterization indices via analysis of variance.The results of grey relation analysis also revealed that the crack length,width,depth,and length density were all highly correlated with root length density,and as the degradation of alpine meadows intensified,the underground biomass increased dramatically,forming a dense layer of grass felt,which has a significant impact on the formation and expansion of cracks.
