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Frontiers of Information Technology & Electronic Engineering 2019年第2期20卷 253-264页

作者： Ting-ting JIN xiao-qiang she xiao-lan QIU Bin LEI Key Laboratory of Technology in Geo-spatial Information Processing and Application System Institute of ElectronicsChinese Academy of Sciences University of Chinese Academy of Sciences Huawei Software Technologies Co. Ltd.

Classification of intertidal area in synthetic aperture radar(SAR) images is an important yet challenging issue when considering the complicatedly and dramatically changing features of tidal fluctuation. The difficulty of intertidal area classification is compounded because a high proportion of this area is frequently flooded by water, making statistical modeling methods with spatial contextual information often ineffective. Because polarimetric entropy and anisotropy play significant roles in characterizing intertidal areas, in this paper we propose a novel unsupervised contextual classification algorithm. The key point of the method is to combine the generalized extreme value(GEV) statistical model of the polarization features and the Markov random field(MRF) for contextual smoothing. A goodness-of-fit test is added to determine the significance of the components of the statistical model. The final classification results are obtained by effectively combining the results of polarimetric entropy and anisotropy. Experimental results of the polarimetric data obtained by the Chinese Gaofen-3 SAR satellite demonstrate the feasibility and superiority of the proposed classification algorithm.

关键词： Intertidal classification Polarimetric synthetic aperture radar Finite mixture model Markov random field Generalized extreme value model

BIBR1532 inhibits proliferation and metastasis of esophageal squamous cancer cells by inducing telomere dysregulation

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World Journal of Gastrointestinal Oncology 2025年第1期17卷 214-225页

作者： Qin Wang Qing-Rong Li Lei Xu Zi-Chun Yuan xiao Liu Mao-Ju Tang Man Luo xiao-Wu Zhong qiang Ma xiao-Lan Guo Department of Clinical Laboratory Affiliated Hospital of North Sichuan Medical CollegeNanchong 637000Sichuan ProvinceChina School of Laboratory Medicine&Translational Medicine Research Center North Sichuan Medical CollegeNanchong 637000Sichuan ProvinceChina

BACKGROUND Esophageal squamous cell carcinoma(ESCC)is a malignant tumor with high morbidity and mortality,and easy to develop resistance to chemotherapeutic *** are DNA-protein complexes located at the termini of chro-mosomes in eukaryotic cells,which are unreplaceable in maintaining the stability and integrity of ***,an RNA-dependent DNA polymerase,play vital role in telomere length maintain,targeting telomerase is a promising therapeutic strategy for ***150 and KYSE410 cells were cultured and exposed to various concentrations of *** viability was assessed at 48 hours and 72 hours to determine the IC50 *** effects of BIBR1532 on ESCC cell proliferation,migration,and cellular senescence were evaluated using the cell counting kit-8 assay,plate colony formation assay,scratch assay,transwell assay,andβ-galactosidase staining,*** blotting was performed to detect the expression of RESULTS The IC50 values for KYSE150 and KYSE410 cells after 48 hours of BIBR1532 exposure were 48.53μM and 39.59μM,*** values decreased to 37.22μM and 22.71μM,respectively,following a longer exposure of 72 ***1532 exhibited dose-dependent effects on KYSE150 and KYSE410 cells,including decreased hTERT expression,inhibition of proliferation and metastasis,and induction of cellular ***,BIBR1532 upregulated the expression of the DDR protein,γ-H2AX,and activated the ataxia telangiectasia and Rad3-related protein(ATR)/check point kinase 1(CHK-1)and ataxia-telangiectasia mutated gene(ATM)/CHK2 ***1532 downregulated the expression of telomere-binding proteins,including telomeric-repeat binding factor 1(TRF1),TRF2,protection of telomeres 1,and TIN2-interacting protein *** a nude mouse xenograft model,BIBR1532 significantly suppressed tumor growth,reduced hTERT expression,and increasedγ-H2AX protein *** and eosin staining of various organs,including the heart,liver,s

关键词： Esophageal squamous cell carcinoma BIBR1532 Human telomerase reverse transcriptase DNA damage response Telomere-binding proteins

Effects of the extrusion parameters on microstructure,texture and room temperature mechanical properties of extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 136-146页

作者： Chenjin Zhang Guangyu Yang Lei xiao Zhiyong Kan Jing Guo qiang Li Wanqi Jie State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China College of Materials Science and Engineering Fuzhou UniversityFuzhou 350108China College of Chemistry and Environmental Science Qujing Normal UniversityQujing 655011China

Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusion speeds(3 and 6 mm/s).The experimental results exhibited that the grain sizes after extrusion were much finer than that of the homogenized alloy,and the second phase showed streamline distribution along the extrusion direction(ED).With extrusion temperature increased from 260 to 320℃,the microstructure,texture,and mechanical properties of alloys changed *** dynamic recrystallization(DRX)degree and grain sizes enhanced as the extrusion ratio increased from 10:1 to 30:1,and the strength gradually decreased but elongation(EL)*** the extrusion speed increased from 3 to 6 mm/s,the grain sizes and DRX degree increased significantly,and the samples presented the typical-rare-earth(RE)*** alloy extruded at 260℃ with extrusion ratio of 10:1 and extrusion speed of 3 mm/s showed the tensile yield strength(TYS)of 213 MPa and EL of 30.6%.After quantitatively analyzing the contribution of strengthening mechanisms,it was found that the grain boundary strengthening and dislocation strengthening played major roles among strengthening *** results provide some guidelines for enlarging the industrial application of extruded Mg-RE alloy.

关键词： Mg-rare earth alloys extrusion temperature extrusion ratio extrusion speed strengthening mechanisms

Ultrasound features of congenital cytomegalovirus infection in the first trimester:A case report

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World Journal of Clinical Cases 2025年第5期13卷 30-35页

作者： xiao-Li Chen Li-qiang Zhang Li-Li Bai Department of Ultrasound Wenzhou Central HospitalWenzhou 325000Zhejiang ProvinceChina

BACKGROUND Congenital cytomegalovirus(CMV)infection represents a significant public health concern as the most prevalent viral infection in newborns,potentially leading to severe neurological and developmental *** majority of cases are asymptomatic and remain undetected during pregnancy due to the absence of effective screening *** SUMMARY A 27-year-old primigravida presented for early pregnancy ultrasound,which revealed an atypical finding:A normal anechoic thalamus appearing hyperechoic on the mid-sagittal view of the fetal *** ultrasound examinations during mid and late gestation demonstrated classic intracranial features sug-gestive of congenital CMV *** karyotyping and microarray analysis of the fetus yielded no significant *** compre-hensive prenatal counseling regarding potential adverse fetal outcomes,the patient elected to continue her *** ultimately underwent cesarean delivery at 42 weeks gestation at another facility,resulting in the birth of a female *** five months of age,the infant presented with epilepsy and significant growth and developmental *** Congenital CMV infection occurs during the first trimester may manifest as hyperechoic thalamus which can be revealed by ultrasound in the mid-saggital view of the fetal *** research should investigate the correlation between echogenic thalamus and developmental outcomes,as well as explore early sc-reening techniques for suspected congenital CMV infection cases.

关键词： Prenatal diagnosis Congenital infection Cytomegalovirus Fetal ultrasound Case report

De novo synthesis of atropisomeric benzofurans via Cu/SPDO complex catalyzed asymmetric formal [3 + 2] annulation

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Science China Chemistry 2025年第01期 174-180页

作者： Fan-xiao Meng Xing-Yu Wang Ka Lu Ju-Song Yang Fu-Min Zhang Ai-Jun Ma Bao Du Yong-qiang Tu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering Lanzhou University School of Chemistry and Chemical Engineering Shanghai Jiao Tong University School of Biotechnology and Health Sciences Wuyi University

Herein, the de novo synthesis of atropisomeric benzofurans through the Cu/spirocyclic-pyrrolidine-oxazoline(SPDO) complex catalyze asymmetric formal [3 + 2] cycloaddition between quinones and ynamides is explored, producing a range of structurally diverse axially chiral benzofurans in satisfactory yields with good to excellent enantioselectivities. Furthermore, density functional theory calculations were applied to explain the possible reaction mechanism.

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Spheroidization of molybdenum powder by radio frequency thermal plasma

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International Journal of Minerals,Metallurgy and Materials 2015年第11期22卷 1212-1218页

作者： xiao-ping Liu Kuai-she Wang Ping Hu qiang Chen Alex A.Volinsky School of Metallurgical Engineering Xi'an University of Architecture & Technology Metallurgical Engineering Research Center of Shaanxi Province State Technical Center Jinduicheng Molybdenum Co.Ltd Department of Mechanical Engineering University of South Florida

To control the morphology and particle size of dense spherical molybdenum powder prepared by radio frequency（RF） plasma from irregular molybdenum powder as a precursor, plasma process parameters were optimized in this paper. The effects of the carrier gas flow rate and molybdenum powder feeding rate on the shape and size of the final products were studied. The molybdenum powder morphology was examined using high-resolution scanning electron microscopy. The powder phases were analyzed by X-ray diffraction. The tap density and apparent density of the molybdenum powder were investigated using a Hall flow meter and a Scott volumeter. The optimal process parameters for the spherical molybdenum powder preparation are 50 g/min powder feeding rate and 0.6 m^3/h carrier gas rate. In addition, pure spherical molybdenum powder can be obtained from irregular powder, and the tap density is enhanced after plasma processing. The average size is reduced from 72 to 62 μm, and the tap density is increased from 2.7 to 6.2 g/cm^3. Therefore, RF plasma is a promising method for the preparation of high-density and high-purity spherical powders.

关键词： powder materials molybdenum radio frequency plasma spheroidization processing parameters

Precise drag prediction of airfoil flows by a new algebraic model

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Acta Mechanica Sinica 2020年第1期36卷 35-43页

作者： Meng-Juan xiao Zhen-Su she State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing100871China

We report the results of accurate prediction of lift(C L)and drag(C D)coefficients of two typical airfoil flows(NACA0012 and RAE2822)by a new algebraic turbulence model,in which the eddy viscosity is specified by a stress length(SL)function predicted by structural ensemble dynamics(SED)*** accuracy of the prediction of C D with error of a few counts(one count is 10−4)and of C L with error under 1%-2%are uniformly obtained for varying angles of attack(AoA),indicating an order of magnitude improvement of drag prediction accuracy compared to currently used models(typically around 20 to 30 counts).More interestingly,the SED-SL model is distinguished with fewer parameters of clear physical meaning,which quantify underlying turbulent boundary layer(TBL)with a universal multi-layer structure,and is thus promising to be more easily generalizable to complex *** use of the new model for the calibration of flow condition in experiment and the extraction of flow physics from numerical simulation data of aeronautic flows are discussed.

关键词： Lift and drag coefficients Airfoil Flows Stress Length Structural ensemble dynamics

Symmetry-based description of laminar-turbulent transition

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Science China(Physics,Mechanics & Astronomy) 2019年第9期62卷 79-85页

作者： Meng-Juan xiao Zhen-Su she Department of Mechanics and Engineering Science and State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking University

We report a simple but accurate description of flat plate transitional flow based on a structural ensemble dynamics(SED) theory of wall turbulence. It is postulated and verified by simulation data that a multi-layer stress length(SL) function ?12 presents a two-state structure in the streamwise x direction, characterizing the laminar-turbulent transition. The resulting algebraic model(called SED-SL) predicts correctly for the first time the entire streamwise profiles of the friction coefficient, Cf(x), of all seven sets of experimental(of e.g. T3 series) and simulations data of flat plate transitional flows, with varying incoming turbulence intensities Tu(or scales), superior to other closure models, with a two-state correlation for transition location Rex*= 3.3 × 10^6(1 +(Tu/0.65)^4)^-1.5/4. The extension to accurate description of transitional flows of engineering interests is discussed.

关键词： SED theory stress length multi-layer

Microstructure and Mechanical Properties in Friction Stir Welded Thick Al–Zn–Mg–Cu Alloy Plate

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Acta Metallurgica Sinica(English Letters) 2022年第8期35卷 1329-1342页

作者： Fei qiang Wen Wang Ke Qiao Pai Peng Ting Zhang xiao-Hu Guan Jun Cai qiang Meng Hua-Xia Zhao Kuai-she Wang School of Metallurgical Engineering National and Local Joint Engineering Research Center for Functional Materials ProcessingXi'an University of Architecture and TechnologyXi'an 710055China Northwest Institute for Non-Ferrous Metal Research Xian 710016China AVIC Manufacturing Technology Institute Bejing 100024China Beijing FSW Technology Co.Ltd Bejing 101107China

In this work, 20-mm-thick aluminum-alloy plates were joined via friction stir welding. The temperature gradient was reduced by reducing the surface welding heat input to achieve uniformity of the mechanical properties across the thick plate joints. The welding temperature was measured using thermocouples. The microstructures were observed via electron backscatter diff raction and transmission electron microscopy. The tensile properties of the samples sliced along the thickness direction of the joint were evaluated. The results show that the highest welding peak temperature is 430℃ on the advancing side on the top surface of the joint. The grain size gradually decreased along the thickness direction, and grain refi nement was due to the combination of continuous, discontinuous, and geometric dynamic recrystallization. The tensile properties of the sliced samples were found to be uniform, and the ultimate tensile strength reached 62% of that of the base metal. The main strengthening mechanism of the Al–Zn–Mg–Cu alloy joints consists of precipitation strengthening. In addition, the η ` → η phase transition and grain coarsening in the heat-affected zone were found to be responsible for the fracture of the joints.

关键词： Friction stir welding Aluminum alloy thick plate Dynamic recrystallization Mechanical properties Precipitated phase

Fabrication and Life Prediction of SSiC Ceramic Joint Joined with Silicon Resin YR3370

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Chinese Journal of Aeronautics 2007年第1期20卷 81-85页

作者： YUAN xiao-kun XU Bing-she School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China College of Materials Science and Engineering Taiyuan University of Technology Taiyuan 030024 China

Joints between sintered silicon carbide （SSiC） were produced using a polysiloxane silicon resin YR3370 （GE Toshiba Silicones） as joining material. Samples were heat treated in a 99.99% nitrogen flux at temperatures ranging from 1 100 ℃ to 1 300 ℃. Three point bending strength of the joint reached the maximum of 179 MPa as joined at 1 200℃. The joining layer is continuous, homogeneous and densified and has a thickness of 2 μm -5μm. The joining mechanism is that the amorphous silicon oxycarbide （SixOyCz） ceramic pyrolyzed from silicon resin YR3370 acts as an inorganic adhesive to SSiC substrate, which means the formation of the continuous Si-C bond structure between SixOyCz structure and SSiC substrate. Life prediction of the ceramic joint can be realized through the measurement of the critical time of the joint after the cyclic loading test.

关键词： silicon resin YR3370 SiC ceramic ceramic joining joint life