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Journal of Integrative Plant Biology 2007年第5期49卷 576-581页

作者： Xue-Mei Ding yun-fei yang Institute of Grassland Science Key Laboratory of Vegetation Ecology Ministry of Education Northeast Normal University Changchun 130024 China

Leymus chinensis （Trin.） Tzveh is a rhizomatous perennial herbage of Gramineae. Reproduction is mainly by vegetative reproduction. Tillering nodes and rhizomes of L. chinensis serve as organs for both vegetative reproduction and nutrient storage. Water-soluble carbohydrate （WSC） contents were measured in tillering nodes, nodes and Internodes of rhizomes of different age classes of L. chinensis populations at three development stages, namely the dough ripe stage, the vegetative growth stage after full ripeness, and the withering stage, in two habitats： sandy soil and saline-alkaline soil. The results showed that WSC content in tillering nodes of the three age classes of L. chinensis were all markedly decreased with increasing age in both sandy soil and saline-alkaline solh A similar trend of changes In WSC contents was observed in the nodes and internodes of rhizomes in different age classes In both habitats. The highest WSC contents were in 2-age-class nodes and internodes of rhizomes, followed by those In the 1 age class, with the lowest WSC contents found in 3-age-class nodes and internodes of rhizomes at the dough ripe and vegetative growth stages after full ripening. In turn, WSC contents decreased with Increasing age at the withering stage in both habitats. The WSC content in each age class of internode was higher than that in the node of rhizome at three development stages in both habitats.

关键词： Leymus chinensis population module rhizome tillering node water-soluble carbohydrate.

Phenotypic Plasticity of Life History Characteristics: Quantitative Analysis of Delayed Reproduction of Green Foxtail (Setaria viridis) in the Songnen Plain of China

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Journal of Integrative Plant Biology 2008年第6期50卷 641-647页

作者： Hai-Yan Li yun-fei yang Institute of Grassland Science Northeast Normal University Key Laboratory of Vegetation Ecology Ministry of Education Changchun 130024 China

Green foxtail （Setaria viridis L.） is a common weed species in temperate regions. Research on the effect of delayed reproduction on the phenotypic plasticity and regularity of the vegetative and reproductive growth is of vital significance for understanding population regulation and control of the weed in the growing season. Green foxtail seeds were sown every 10 days from 25 June to 24 August of 2004. The growth and production metrics were measured via harvesting tufts and statistical analysis was carried out. The results showed that the reproductive tillers, seed number, seed biomass and one thousand-seed weight of plants at the first sowing （25 June） approximately increased 28.8, 7 827.0, 1 104,0 and 12.3 times compared with that at the last sowing （24 August）, respectively. Total tillers, reproductive tillers and height increased linearly as the reproductive period delayed, however, biomass increased exponentially. Quadratic equations best explained the relationships between the delayed reproductive period and seed number, inflorescence length, one thousand-seed weight, seed biomass. Based on the quantity and quality of seed production, weeding young seedlings emerging before July can be the most effective weed-control strategy in the Songnen Plain.

关键词： delayed reproduction life history phenotypic plasticity quantitative characteristics Setaria viridis weed control

Identification of emission sources of umbral flashes using phase congruency

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Research in Astronomy and Astrophysics 2014年第8期14卷 1001-1010页

作者： Song Feng Lan Yu yun-fei yang Kai-Fan Ji yunnan Key Laboratory of Computer Technology Application/Faculty of Information Engineering and Automation Kunming University of Science and Technology Key Laboratory of Solar Activity National Astronomical ObservatoriesChinese Academy of Sciences Department of Information Engineering Yunnan Land and Resources Vocational College

The emission sources of umbral flashes （UFs） are believed to be closely related to running umbral and penumbral waves, and are concluded to be associated with umbral dots in the solar photosphere. Accurate identification of emission sources of UFs is crucial for investigating these physical phenomena and their inherent relationships. A relatively novel model of shape perception, namely phase congruency （PC）, uses phase information in the Fourier domain to identify the geometrical shape of the region of interest in different intensity levels, rather than intensity or gradient. Previous studies indicate that the model is suitable for identifying features with low contrast and low luminance. In the present paper, we applied the PC model to identify the emission sources of UFs and to locate their positions. For illustrating the high performance of our proposed method, two time sequences of Ca n H images derived from the Hinode/SOT on 2010 August 10 and 2013 August 20 were used. Furthermore, we also compared these results with the analysis results that are identified by the traditional/classical identification methods, including the gray-scale adjusted technique and the running difference technique. The result of our analysis demonstrates that our proposed method is more accurate and effective than the traditional identification methods when applied to identifying the emission sources of UFs and to locating their positions.

关键词： techniques image processing -- Sun chromosphere -- Sun photo- sphere -- sunspots -- convection

Evolution of isolated G-band bright points: size, intensity and velocity

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Research in Astronomy and Astrophysics 2014年第6期14卷 741-752页

作者： yun-fei yang Jia-Ben Lin Song Feng Kai-Fan Ji Hui Deng Feng Wang Faculty of Information Engineering and Automation/yunnan Key Laboratory of Computer Technology Application Kunming University of Science and Technology Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Ministry of Education

We study the evolution pattern of isolated G-band bright points （GBPs） in terms of their size, intensity and velocity. Using a high resolution image sequence taken with the Hinode/Solar Optical Telescope （SOT）, we detect GBPs in each image by the Laplacian and Morphological Dilation algorithm, and track their evolutions by a 26-adjacent method in a three-dimensional space-time cube. For quantifying the evolution, we propose a quantification method based on lifetime normalization which aligns the different lifetimes to common stages. The quantification results show that, on average, the diameter of isolated GBPs changes from 166 to 173 km, then down to 165 km; the maximum intensity contrast changes from 1.012 to 1.027, then down to 1.011; however, the velocity changes from 1.709 to 1.593 km s-1, then up to 1.703 km s-i. The results indicate that the evolution follows a pattern such that the GBP is small, faint and fast-moving at the birth stage, becomes big, bright and slow-moving at the middle stage, then gets small, faint and fast-moving at the decay stage until disappearance. Although the differences are very small, a two-sample t-test is used to demonstrate there are significant differences in means between the distri- butions of the different stages. Furthermore, we quantify the relationship between the lifetimes of GBPs and their properties. It is found that there are positive correlations between the lifetimes and their sizes and intensities with correlation coefficients of 0.83 and 0.65, respectively; however, there is a negative correlation between the life- times and velocities with a correlation coefficient of-0.49. In summary, the longer the GBP persists, the bigger, brighter and slower it will be.

关键词： techniques: image processing -- Sun: photosphere -- methods: dataanalysis -- methods: statistical

Prediction of sintered density of binary W(Mo)alloys using machine learning

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Rare Metals 2023年第8期42卷 2713-2724页

作者： He-Xiong Liu yun-fei yang Yong-Feng Cai Chang-Hao Wang Chen Lai Yao-Wu Hao Jin-Shu Wang Key Laboratory of Advanced Functional Materials Ministry of EducationFaculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China Department of Materials Science and Engineering University of Texas at ArlingtonArlingtonTX 76019USA

Powder metallurgy is the optimal method for the consolidation and preparation of W(Mo)alloys,which exhibit excellent application prospects at high *** properties of W(Mo)alloys are closely related to the sintered ***,controlling the sintered density and porosity of these alloys is still *** the past,the regulation methods mainly focused on timeconsuming and costly trial-and-error *** this study,the sintering data for more than a dozen W(Mo)alloys constituted a small-scale dataset,including both solid and liquid phases ***,simple descriptors were used to predict the sintered density of W(Mo)alloys based on the descriptor selection strategy and machine learning method(ML),where ML algorithm included the least absolute shrinkage and selection operator(Lasso)regression,k-nearest neighbor(k-NN),random forest(RF),and multi-layer perceptron(MLP).The results showed that the interpretable descriptors extracted by our proposed selection strategy and the MLP neural network achieved a high prediction accuracy(R>0.950).By further predicting the sintered density of W(Mo)alloys using different sintering processes,the error between the predicted and experimental values was less than 0.063,confirming the application potential of the model.

关键词： Sintered density W(Mo)alloy Machine learning(ML) Interpretable descriptors Multi-layer perceptron(MLP)

Artificial intelligence improves accuracy, efficiency, and reliability of a handheld infrared eccentric autorefractor for adult refractometry

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International Journal of Ophthalmology(English edition) 2022年第4期15卷 628-634页

作者： Yi-Ting Cao Dan-yang Che Yi-Lei Pan yun-Li Lu Chong-yang Wang Xiao-Li Zhang yun-fei yang Ke-Ke Zhao Ji-Bo Zhou Department of Ophthalmology Shanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineShanghai 200011China Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology Shanghai 200011China Shanghai MediWorks Precision Instruments Company Limited Shanghai 201112China Department of Ophthalmology Shanghai Children’s Medical CenterShanghai Jiao Tong University School of MedicineShanghai 200127China

AIM: To evaluate the accuracy, efficiency, and reliability of a handheld infrared eccentric autorefractor(h ICA) with artificial intelligence(AI) by comparing its refraction measurements to those recorded using h ICA and a clinical table-mounted automatic refractor(TAR).METHODS: A cross-sectional study using three optometers, including h ICA with or without AI and TAR, for refractometry of adults(aged 19-49 years old) with no signs of ocular disease or trauma in the absence of cycloplegia. Right and left eye refraction data were recorded, including the spherical equivalent(SE), diopter of spherical power(DS), diopter of cylindrical power(DC) decomposed into vectors J0 and J45, and measurement times. To avoid analytical difficulties associated with the interdependence of observations between eyes from the same individual, the Generalized Estimation Equation was used to compare the SE, DS, J0 and J45 measurements, and the times thereof, among the different groups. The intraclass correlation coef f icient(ICC) and Spearman’s rank correlation coefficient were used to evaluate correlations among the measurements recorded by the three different instruments. Bland-Altman were used to analyze the precision of the equipment by the agreement. RESULTS: A total of 70 patients(140 eyes;mean age: 31.37 y;range: 19-49 y) were assessed using refractometry. In a brightly lit environment, there was no significant difference between the mean SE recorded using TAR and that recorded using h ICA with AI or without AI(both P>0.05). In an intense-light environment, h ICA equipped with AI showed a better detection rate than without AI. Light intensity had a greater effect on dioptric measurements recorded using h ICA without AI(P<0.001) than on those recorded using the one equipped with AI(P<0.05). Measurement times varied significantly between the different light intensities and instruments(P<0.05).CONCLUSION: For the normal human eyes, AI may improve the accuracy, efficiency, and reliabil

关键词： dioptric measurement artificial intelligence equipment design infrared eccentric autorefractor

Investigation of intergranular bright points from the New Vacuum Solar Telescope

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Research in Astronomy and Astrophysics 2016年第5期16卷 69-80页

作者： Kai-Fan Ji Jian-Ping Xiong Yong-Yuan Xiang Song Feng Hui Deng Feng Wang yun-fei yang Faculty of Information Engineering and Automation/yunnan Key Laboratory of Computer Technology Application Kunming University of Science and Technology Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Ministry of Education yunnan Observatories Chinese Academy of Sciences

Six high-resolution TiO-band image sequences from the New Vacuum Solar Telescope （NVST） are used to investigate the properties of intergranular bright points （igBPs）. We detect the igBPs using a Laplacian and morphological dilation algorithm （LMD） and automatically track them using a three- dimensional segmentation algorithm, and then investigate the morphologic, photometric and dynamic prop- erties of igBPs in terms of equivalent diameter, intensity contrast, lifetime, horizontal velocity, diffusion index, motion range and motion type. The statistical results confirm previous studies based on G-band or TiO-band igBPs from other telescopes. These results illustrate that TiO data from the NVST are stable and reliable, and are suitable for studying igBPs. In addition, our method is feasible for detecting and track- ing igBPs with TiO data from the NVST. With the aid of vector magnetograms obtained from the Solar Dynamics Observatory/Helioseismic and Magnetic Imager, the properties of igBPs are found to be strongly influenced by their embedded magnetic environments. The areal coverage, size and intensity contrast values of igBPs are generally larger in regions with higher magnetic flux. However, the dynamics of igBPs, includ- ing the horizontal velocity, diffusion index, ratio of motion range and index of motion type are generally larger in the regions with lower magnetic flux. This suggests that the absence of strong magnetic fields in the medium makes it possible for the igBPs to look smaller and weaker, diffuse faster, and move faster and further along a straighter path.

关键词： techniques: image processing -- Sun: photosphere -- methods: data analysis -- methods:statistical

Characterizing motion types of G-band bright points in the quiet Sun

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Research in Astronomy and Astrophysics 2015年第4期15卷 569-582页

作者： yun-fei yang Hui-Xue Qu Kai-Fan Ji Song Feng Hui Deng Jia-Ben Lin Feng Wang Faculty of Information Engineering and Automation / yunnan Key Laboratory of Computer Technology Application Kunming University of Science and Technology Key Laboratory of Solar Activity National Astronomical ObservatoriesChinese Academy of Sciences Key Laboratory of Modern Astronomy and Astrophysics Nanjing UniversityMinistry of Education yunnan Observatories Chinese Academy of Sciences

We study the motion of G-band bright points （GBPs） in the quiet Sun to obtain the characteristics of different motion types. A high resolution image sequence taken with the Hinode/Solar Optical Telescope （SOT） is used, and GBPs are automat- ically tracked by segmenting 3D evolutional structures in a space-time cube. After putting the GBPs that do not move during their lifetimes aside, the non-stationary GBPs are categorized into three types based on an index of their motion type. Most GBPs that move in straight or nearly straight lines are categorized as a straight mo- tion type, a few moving in rotary paths into rotary motion, and the others fall into a motion type we called erratic. The mean horizontal velocities are 2.18±0.08 km s-1, 1.63±0.09km s^-1 and 1.33±0.07 km s^-1 for straight, erratic and rotary motion types, respectively. We find that a GBP drifts at a higher and constant velocity during its whole life if it moves in a straight line. However, it has a lower and variational velocity if it moves on a rotary path. The diffusive process is ballistic-, super- and sub-diffusion for straight, erratic and rotary motion types, respectively. The corresponding diffusion index （γ） and coefficients （K） are 2.13±0.09 and 850±37km^2 s^-1, 1.82±0.07 and 331 ±24 km^2 s^-1, and 0.73±0.19 and 13±9 km^2 s^-1. In terms of direction of motion, it is homogeneous and isotropic, and usually persists between neighboring frames, no matter what motion type a GBP is classified as.

关键词： techniques: image processing -- Sun: photosphere -- methods: dataanalysis -- methods: statistical

Porous and Ultra-Flexible Crosslinked MXene/Polyimide Composites for Multifunctional Electromagnetic Interference Shielding

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Nano-Micro Letters 2022年第4期14卷 59-74页

作者： Zhi-Hui Zeng Na Wu Jing-Jiang Wei yun-fei yang Ting-Ting Wu Bin Li Stefanie Beatrice Hauser Wei-Dong yang Jiu-Rong Liu Shan-Yu Zhao Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of Education and School of Materials Science and EngineeringShandong UniversityJinan 250061People’s Republic of China Department of Chemistry and Applied Biosciences ETH ZurichCH-8093 ZurichSwitzerland Laboratory for Cellulose and Wood Materials Swiss Federal Laboratories for Materials Science and Technology(Empa)8600 DübendorfSwitzerland Laboratory for Building Energy Materials and Components Swiss Federal Laboratories for Materials Science and Technology(Empa)8600 DübendorfSwitzerland School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092People’s Republic of China

Lightweight,ultra-flexible,and robust crosslinked transition metal carbide(Ti3C2 MXene)coated polyimide(PI)(C-MXene@PI)porous composites are manufactured via a scalable dip-coating followed by chemical crosslinking *** addition to the hydrophobicity,anti-oxidation and extreme-temperature stability,efficient utilization of the intrinsic conductivity of MXene,the interfacial polarization between MXene and PI,and the micrometer-sized pores of the composite foams are ***,the composites show a satisfactory X-band electromagnetic interference(EMI)shielding effectiveness of 22.5 to 62.5 dB at a density of 28.7 to 48.7 mg cm−3,leading to an excellent surface-specific SE of 21,317 dB cm^(2)g^(−1).Moreover,the composite foams exhibit excellent electrothermal performance as flexible heaters in terms of a prominent,rapid reproducible,and stable electrothermal effect at low voltages and superior heat performance and more uniform heat distribution compared with the commercial heaters composed of alloy ***,the composite foams are well attached on a human body to check their electromechanical sensing performance,demonstrating the sensitive and reliable detection of human motions as wearable *** excellent EMI shielding performance and multifunctionalities,along with the facile and easy-to-scalable manufacturing techniques,imply promising perspectives of the porous C-MXene@PI composites in next-generation flexible electronics,aerospace,and smart devices.

关键词： MXene Polyimide Electromagnetic interference shielding Heater Sensor

A review on recent progress of thermionic cathode

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Tungsten 2020年第3期2卷 289-300页

作者： Jun‑Yan Gao yun‑fei yang Xiao‑Ke Zhang Shi‑Lei Li Peng Hu Jin‑Shu Wang Key Laboratory of Advanced Functional Materials Education Ministry of ChinaFaculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China

As the performance of vacuum electron devices is essentially governed by the properties of their cathodes,developing efficient and durable thermionic cathode is necessary and highly desired to meet the boosting requirements of vacuum electron *** review summarized the progress made in the past decades with a detailed discussion on the occurred various thermionic cathodes and their features,and the understandings of the correlation between the emission properties and the composition,where structure and synthesis method are well ***,dispenser cathodes with novel structures and emission mechanism are highlighted to indicate the recent achievement in this area of research,and Sc-cathode is considered as a promising candidate for the next-generation vacuum electron devices due to the greatly improved ***,challenges still exist to meet the ever-growing demands of thermionic cathode with collaborative requirement of high performance,easy fabrication and inadequate reproducibility.

关键词： Thermionic cathodes Performance Emission mechanism Ion bombardment Work function Tungsten