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Resolution Enhancement of SOHO/MDI Magnetograms

Research in Astronomy and Astrophysics 2024年第6期24卷 358-367页

作者： Ying Qin Kai-Fan Ji Hui Liu xiao-guang yu yunnan Observatories Chinese Academy of SciencesKunming 650011China University of Chinese Academy of Sciences Beijing 100049China yunnan Key Laboratory of Solar Physics and Space Science Kunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China

Research on the solar magnetic field and its effects on solar dynamo mechanisms and space weather events has benefited from the continual improvements in instrument resolution and measurement *** augmentation and assimilation of historical observational data timelines also play a significant role in understanding the patterns of solar magnetic field *** the realm of astronomical data processing,super-resolution(SR)reconstruction refers to the process of using a substantial corpus of training data to learn the nonlinear mapping between low-resolution(LR)and high-resolution(HR)images,thereby achieving higherresolution astronomical *** paper is an application study in high-dimensional nonlinear *** learning models were employed to perform SR modeling on SOHO/MDI magnetograms and SDO/HMI magnetograms,thus reliably achieving resolution enhancement of full-disk SOHO/MDI magnetograms and enhancing the image resolution to obtain more detailed *** this study,a data set comprising 9717pairs of data from 2010 April to 2011 February was used as the training set,1332 pairs from 2011 March were used as the validation set and 1034 pairs from 2011 April were used as the test *** data preprocessing,we randomly cropped 128×128 sub-images as the LR cases from the full-disk MDI magnetograms,and the corresponding 512×512 sub-images as HR ones from the HMI full-disk magnetograms for model *** tests conducted have shown that the study successfully produced reliable 4×SR reconstruction of full-disk MDI *** MESR model's results(0.911)were highly correlated with the target HMI magnetographs as indicated by the correlation coefficient ***,the method achieved the best PSNR,SSIM,MAE and RMSE values,indicating that the MESR model can effectively reconstruct magnetograms.

关键词： magnetic fields techniques:image processing virtual observatory tools Sun:magnetic fields

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Controlled synthesis and optical properties of Ce^(3+)/Tb^(3+) co-doped BaGdF_5 nanocrystals

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Rare Metals 2015年第9期34卷 673-678页

作者： Chun-Yan Cao An Xie xiao-guang yu College of Mathematics and Physics Jinggangshan University School of Materials Science and Engineering Xiamen University of Technology

Based on a hydrothermal method, the Ce3+/Tb3+ co-doped Ba Gd F5 nanocrystals were synthesized by controlling the introduction concentration of Ba2+ and Gd3+. The samples were characterized by X-ray diffraction(XRD), field emission scanning electron microscopy(FESEM) images, photoluminescence(PL) excitation, and emission spectra, as well as the photoluminescence dynamic decay curves. With the increase of the Ba2+ concentration in the synthesis procedure, the positions of diffraction peaks of XRD patterns move toward lower degree, and the case of the samples synthesized with the increase of the Gd3+ concentration is contrary, which consists well with each other. The FE-SEM images suggest that the BaGdF5 nanocrystals are in spherical morphology,and the average diameters decrease with the increase of Ba2+ or Gd3+ concentration. For the 4f–5d transition of Ce3+ is sensitive to the environment of local lattice, the PL excitation and emission spectra of the samples are different. The 4f–4f transition of Tb3+ also presents different optical properties in different host lattices. The variations of the optical properties of Ce3+ and Tb3+ as well as the lifetime of the 5D4+7F5 emission of Tb3+ are also consistent well with each other in the two series of samples.

关键词： Hydrothermal synthesis Optical properties Nanocrys

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Permeation of dimethyl sulfoxide into articular cartilage at subzero temperatures

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2012年第3期13卷 213-220页

作者： Shao-zhi ZHANG xiao-yi yu guang-ming CHEN Institute of Refrigeration and Cryogenics Zhejiang University Hangzhou 310027 China

Osteochondral allografting has been proved to be a useful method to treat diseased or damaged areas of joint surfaces. Operational long-term stocks of grafts which supply a buffer between procurement and utilization would contribute to the commercialization or industrialization of this technology. Vitrification has been thought to be a promising method for successful preservation of articular cartilage （AC）, but high concentration cryoprotectants （CPAs） are used which may cause high cellular toxicity. An effective way to reduce CPA toxioity is to increase CPA concen- tration gradually while the temperature is lowered. Understanding the mechanism of （31~A permeation at subzero temperatures is important for designing the cryopreservation protocol. In this research, the permeation of dimethyl sulfoxide （MezSO） in ovine AC at subzero temperatures was studied experimentally. Pretreated AC discs were ex- posed in Me2SO solutions for different time （0, 5, 15, 30, 50, 80, and 120 min） at three temperature levels （-10, -20, and -30℃）. The Me2SO concentration within the tissue was determined by ultraviolet （UV） spectrophotometry. The diffusion coefficients were estimated to be 0.85×10-6, 0.48×10-8, and 0.27×10-6 cm2/s at -10, -20, and -,30℃, respectively, and the corresponding activation energy was 29.23 kJ/mol. Numerical simulation was performed to com- pare two Me2SO addition protocols, and the results demonstrated that the total loading duration could be effectively reduced with the knowledge of permeation kinetics.

关键词： Articular cartilage Vitrification Dimethyl sulfoxide Permeation Diffusion coefficient Subzero temperature

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Influence of Integral Instability of Kramers-Kronig Transformation on Photoabsorption Cross Sections

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Communications in Theoretical Physics 2009年第8期52卷 369-376页

作者： MA xiao-guang GONG yu-Bing QU Zhao-Jun Department of Physics Ludong University Yantai 264025 China

The photoabsorption cross sections of condensed atoms and molecules have proven to be dependent not only on the imaginary parts but also on the real parts of the polarizabilities due to the strong interatomie interactions in condensed environment. The real parts of the polarizabilities calculated usually by using the famous Kramers-Kronig transformation （KKT） from the photoabsorption cross sections of the isolated atoms are very sensitive to the accuracy of the implementation method of the infinite integral in the KKT. The influence of the integral instability of the KKT and the real part of the polarizability on the variation of the photoabsorption cross sections with the number density and the structure of the condensed matter has been studied in the present work for the first time. The conclusion is that the integration method with interpolation has given more reasonable results than the direct truncation method if some appropriate interpolation functions have been used. Some notes and conclusions have also been given for the applications of the alternative coupled expressions of photoabsorption cross sections.

关键词： condensed-phase photoabsorption Kramers-Kronig transformation dynamic polarizability

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Highly Thermoconductive,Strong Graphene‑Based Composite Films by Eliminating Nanosheets Wrinkles

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Nano-Micro Letters 2024年第1期16卷 328-340页

作者： guang xiao Hao Li Zhizhou yu Haoting Niu Yagang Yao College of Engineering and Applied Sciences Jiangsu Key Laboratory of Artificial Functional Materialsand Collaborative Innovation Center of Advanced MicrostructuresNational Laboratory of Solid State MicrostructuresNanjing UniversityNanjing 210093People’s Republic of China Institute of Laser Manufacturing Henan Academy of SciencesZhengzhou 450052People’s Republic of China Center for Quantum Transport and Thermal Energy Science School of Physics and TechnologyNanjing Normal UniversityNanjing 210023People’s Republic of China

Graphene-based thermally conductive composites have been proposed as effective thermal management materials for cooling high-power electronic ***,when flexible graphene nanosheets are assembled into macroscopic thermally conductive composites,capillary forces induce shrinkage of graphene nanosheets to form wrinkles during solution-based spontaneous drying,which greatly reduces the thermal conductivity of the ***,graphene nanosheets/aramid nanofiber(GNS/ANF)composite films with high thermal conductivity were prepared by in-plane stretching of GNS/ANF composite hydrogel networks with hydrogen bonds andπ-π*** in-plane mechanical stretching eliminates graphene nanosheets wrinkles by suppressing inward shrinkage due to capillary forces during drying and achieves a high in-plane orientation of graphene nanosheets,thereby creating a fast in-plane heat transfer *** composite films(GNS/ANF-60 wt%)with eliminated graphene nanosheets wrinkles showed a significant increase in thermal conductivity(146 W m^(−1)K^(−1))and tensile strength(207 MPa).The combination of these excellent properties enables the GNS/ANF composite films to be effectively used for cooling flexible LED chips and smartphones,showing promising applications in the thermal management of high-power electronic devices.

关键词： Graphene Aramid nanofiber Wrinkles elimination In-plane stretching Thermal conductivity

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A large-scale gene discovery for the red palm weevil Rhynchophorus ferrugineus （Coleoptera： Curculionidae）

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Insect Science 2013年第6期20卷 689-702页

作者： Lei Wang xiao-Wei Zhang Lin-Lin Pan Wan-Fei Liu Da-Peng Wang guang-yu Zhang yu-Xin Yin An Yin Shan-Gang Jia xiao-guang yu Gao-yuan Sun Song-Nian Hu Ibrahim S. AI-Mssallem Jun yu Joint Center for Genomics Research (JCGR) King Abdulaziz City for Science and Technology (KACST) and Chinese Academy of Sciences (CAS) Riyadh Kingdom of Saudi Arabia CAS Key Laboratory of Genome Sciences and Information Beijing Institute of Genomics Chinese Academy of Sciences Beijing Graduate University of Chinese Academy of Sciences Beijing China Department of Biotechnology College of Agriculture and Food Sciences King Faisal University AI-Hssa Hofuf Kingdom of Saudi Arabia

The red palm weevil （RPW; Rhynchophorusferrugineus） is a devastating pest of palms, prevalent in the Middle East as well as many other regions of the world. Here, we report a large-scale de novo complementary DNA （cDNA） sequencing effort that acquired ~5 million reads and assembled them into 26 765 contigs from 12 libraries made from samples of different RPW developmental stages based on the Roche/454 GS FLX platform. We annotated these contigs based on the publically available known insect genes and the Tribolium castaneum genome assembly. We find that over 80% of coding sequences （CDS） from the RPW contigs have high-identity homologs to known proteins with complete CDS. Gene expression analysis shows that the pupa and larval stages have the highest and lowest expression levels, respectively. In addition, we also identified more than 60 000 single nucleotide polymorphisms and 1 200 simple sequence repeat markers. This study provides the first large-scale eDNA dataset for RPW, a much-needed resource for future molecular studies.

关键词： full-length cDNA gene expression GS FLX Titanium pest red palm weevil

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Impact wear properties of dissimilar joints between bainitic frogs and pearlite rails

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Journal of Iron and Steel Research International 2024年第1期31卷 275-287页

作者： Pin-yong Zeng Chun-guang Zuo xiao-yu Zhang Wei Li Tribology Research Institute Southwest Jiaotong UniversityChengdu610031SichuanChina

The impact wear behavior and damage mechanism of dissimilar welded joints between U26Mn frog and U75 V rail before and after normalizing treatment were studied by cyclic impact *** experiment indicated that the impact wear volume of the joints increased with the increasing number of impact *** main wear mechanisms include pitting wear,mild fatigue wear,delamination wear,and fatigue wear,and plastic deformation was the primary impact wear *** them,fatigue wear had the greatest influence on wear volume,while other wear mechanisms had limited *** impact wear resistance of the base material was better than that of the heat-affected *** treatment was beneficial to improving the impact wear resistance of welded joints owing to its effect to promote pearlite recovery,grain refinement,and uniform distribution of *** martensite generated in the rail welded joints aggravated the impact wear damage to the materials,which should be avoided.

关键词： Dissimilar welded joint Impact wear Bainitic steel Damage mechanism Wear rate

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Effect of Mn addition on microstructure and mechanical properties of GX40CrNiSi25-12 austenitic heat resistant steel

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China Foundry 2024年第3期21卷 205-212页

作者： Guan-yu Jiang Meng-wu Wu xiao-guang Yang Hui Wang yu-yuan Zhu Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 441000HubeiChina Wescast Industries(China)Co. Ltd.Wuhan 430100China

Three types of steels were designed on the basis of GX40CrNiSi25-12 austenitic heat resistant steel by adding different Mn contents(2wt.%,6wt.%,and 12wt.%).Thermodynamic calculation,microstructure characterization and mechanical property tests were conducted to investigate the effect of Mn addition on the microstructure and mechanical properties of the austenitic heat resistant *** show that the matrix structure in all the three types of steels at room temperature is completely *** NbC and M_(23)C_(6)precipitate at grain boundaries of austenite *** the increase of Mn content,the number of carbides increases and their distribution becomes more *** the Mn content increases from 1.99%to 12.06%,the ultimate tensile strength,yield strength and elongation increase by 14.6%,8.0%and 46.3%,*** improvement of the mechanical properties of austenitic steels can be explained by utilizing classic theories of alloy strengthening,including solid solution strengthening,precipitation strengthening,and grain *** increase in alloy strength can be attributed to solid solution strengthening and precipitation strengthening caused by the addition of *** improvement of the plasticity of austenitic steels can be explained from two aspects:grain refinement and homogenization of precipitated phases.

关键词： austenitic heat resistant steel manganese microstructure mechanical properties

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Modeling of Strain-Induced Precipitation Kinetics and Evolution of Austenite Grains in Nb Microalloyed Steels

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Journal of Iron and Steel Research International 2008年第3期15卷 65-69页

作者： ZHOU xiao-guang LIU Zhen-yu yuAN Xiang-qian WU Di WANG Guo-dong LIU Xiang-hua State Key Laboratory of Rolling Technology and Automation Northeastern University Shenyang 110004 Liaoning China

Considering the effect of strain and chemical composition onprecipitation behavior, new models for the start and end time of Nb（C,N） precipitation in austenite under the conditions of different temperatures and strains have been investigated for Nb microalloyed steel. The value of n in the precipitation kinetic equation has been determined by using the available experimental data in literature, which indicated that n is a constant and independent of temperature. The values of the start and end time of the predicted precipitation are compared with the experimental values. Calculated results are in good agreement with the experimental results. Also, the evolution of austenite grains before ferrite transformation is simulated by taking the effect of precipitation into consideration. The measured austenite grain size is in good agreement with predicted one prior to ferrite transformation.

关键词： strain-induced precipitation start time precipitation static recrystallization grain size

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A correction method for the telluric absorptions and application to Lijiang Observatory

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Research in Astronomy and Astrophysics 2021年第7期21卷 281-289页

作者： Kai-Xing Lu Zhi-Xiang Zhang Ying-Ke Huang An-Bing Ren Liang Xu Hai-Cheng Feng yu-Xin Xin Xu Ding xiao-guang yu Jin-Ming Bai yunnan Observatories Chinese Academy of SciencesKunming 650011China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650011China Department of Astronomy Xiamen UniversityXiamen 361005China Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100094China Department of Astronomy China West Normal UniversityNanchong 637002China

Observing a telluric standard star for correcting the telluric absorption lines of spectrum will take a significant amount of precious telescope time,especially in the long-term spectral monitoring *** that,it is difficult to select a suitable telluric standard star near in both time and airmass to the scientific *** this paper,we present a method of correcting the telluric absorption lines by combining the advantages of long slit *** rotating the slit,we observed the scientific object and a nearby comparison star in one exposure,so that the spectra of both objects should have the same telluric transmission *** telluric transmission spectrum was constructed by dividing the observed spectrum of the comparison star by its stellar template,and was used to correct the telluric absorption lines of the scientific *** the long slit spectrograph of the Lijiang 2.4-meter telescope,we designed a long-term spectroscopic observation strategy,and finished a four-year spectroscopic monitoring for a pair of objects(an active galactic nucleus and a non-varying comparison star).We applied this method to correct the telluric absorption lines of the long-term monitored spectra by the Lijiang 2.4-meter telescope,and investigated the variation of the telluric absorptions at Lijiang *** found that the telluric absorption transparency is mainly modulated by the seasonal variability of the relative humidity,airmass and *** the scatter of the [O Ⅲ] λ5007 fluxes emitted from the narrow-line region of active galactic nuclei as an indicator,we found that the correction accuracy of the telluric absorption lines is 1%.

关键词： techniques:telluric absorption methods:data analysis techniques:spectroscopic quasars:individual(SDSS J1536+0441)

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