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Fast implementation of kernel simplex volume analysis based on modified Cholesky factorization for endmember extraction

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Frontiers of Information Technology & Electronic Engineering 2016年第3期17卷 250-257页

作者： Jing LI xiao-run LI Li-jiao WANG Liao-ying ZHAO College of Electrical Engineering Zhejiang University Institute of Computer Application Technology Hangzhou Dianzi University

Endmember extraction is a key step in the hyperspectral image analysis process. The kernel new simplex growing algorithm （KNSGA）, recently developed as a nonlinear alternative to the simplex growing algorithm （SGA）, has proven a promising endmember extraction technique. However, KNSGA still suffers from two issues limiting its application. First, its random initialization leads to inconsistency in final results; second, excessive computation is caused by the iterations of a simplex volume calculation. To solve the first issue, the spatial pixel purity index （SPPI） method is used in this study to extract the first endrnember, eliminating the initialization dependence. A novel approach tackles the second issue by initially using a modified Cholesky fac- torization to decompose the volume matrix into triangular matrices, in order to avoid directly computing the determinant tauto- logically in the simplex volume formula. Theoretical analysis and experiments on both simulated and real spectral data demonstrate that the proposed algorithm significantly reduces computational complexity, and runs faster than the original algorithm.

关键词： Endmember extraction Modified Cholesky factorization Spatial pixel purity index (SPPI) New simplex growingalgorithm (NSGA) Kernel new simplex growing algorithm (KNSGA)

Neutropenia:diagnosis and management

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World Journal of Pediatrics 2022年第11期18卷 771-777页

作者： Jing Zhang xiao-Yan Wu run-Ming Jin Department of Pediatrics Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430022China

Neutropenia is definedas an absolute neutrophil count(ANC)of less than 1500/μ*** to the number of circulating neutrophils,neutropenia is divided into mild(1000/μL≤ANC<1500/μL),mode rate(500/μL≤ANC<1000/μL),and ... 详细信息

关键词： diagnosis absolute neutrophil

Study on secondary electron suppression in compact D–D neutron generator

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Nuclear Science and Techniques 2019年第5期30卷 139-145页

作者： Zhi-Wu Huang xiao-Hou Bai Chang-Qi Liu Jun-run Wang Zhan-Wen Ma xiao-Long Lu Zheng Wei zi-Min Zhang Yu Zhang Ze-En Yao School of Nuclear Science and Technology Lanzhou University Engineering Research Center for Neutron Application Technology Ministry of EducationLanzhou University Institute of Modern Physics Chinese Academy of Sciences

A compact D–D neutron generator, with a peak neutron yield of D–D reactions up to 2.48×10~8 n/s is being developed at Lanzhou University in China for application in real-time neutron activation analysis. During tests, the problem of back acceleration of secondary electrons liberated from the neutron production target by deuterium ions bombardment was encountered. In this study,an electric field method and a magnetic field method for suppressing secondary electrons are designed and experimentally investigated. The experimental results show that the electric field method is superior to the magnetic field method. Effective suppression of the secondary electrons can be achieved via electrostatic suppression when the bias voltage between the target and the extraction-accelerating electrode is >204 V. Furthermore, the secondary electron emission coefficient for the mixed deuterium ion(D_1^+,D_2^+, and D_3^+) impacting on molybdenum is estimated. In the deuterium energy range of 80–120 keV, the estimated secondary electron emission coefficients are approximately 5–5.5 for the mixed deuterium ion glancing incidence of 45° and approximately 3.5–3.9 for the mixed deuterium ion normal incidence.

关键词： D–D neutron generator Secondary electron suppression Secondary electron emission coefficient

g-C_(3)N_(4)nanosheets coupled with CoSe_(2)as co-catalyst for efficient photooxidation of xylose to xylonic acid

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Green Energy & Environment 2025年第1期10卷 231-238页

作者： Qi Hao Yijun Liu Ren Zou Ge Shi Shilian Yang Linxin Zhonga Wu Yang xiao Chi Yunpeng Liu Shimelis Admassie Xinwen Peng State Key Laboratory of Pulp and Paper Engineering South China University of TechnologyGuangzhou510641GuangdongChina Hainan Key Laboratory of Storage&Processing of Fruits and Vegetables Agricultural Products Processing Research InstituteChinese Academy of Tropical Agricultural SciencesZhanjiangGuangdong524001China Department of Chemistry and Centre for Advanced 2D Materials(CA2DM)National University of Singapore 3 Science Drive 3 Singapore117543Singapore School of Materials Science and Hydrogen Energy Foshan UniversityFoshan528231GuangdongChina Department of Chemistry Addis Ababa UniversityPO BOX 1176Addis AbabaEthiopia

Photocatalysis has emerged as an effective approach to sustainably convert biomass into value-added ***_(2)is a promising nonprecious,efficient cocatalyst for photooxidation,which can facilitate the separation of photogenerated electron–holes,increase the reaction rates,and enhance photocatalytic *** this work,we synthesized a stable and efficient photocatalysis system of CoSe_(2)/g-C_(3)N_(4)through attaching CoSe_(2)on g-C_(3)N_(4)sheets,with a yield of 50.12%for the selective photooxidation of xylose to xylonic *** light illumination,the photogenerated electrons were prone to migrating from g-C_(3)N_(4)to CoSe_(2)due to the higher work function of CoSe_(2),resulting in the accelerated separation of photogenerated electron–holes and the promoted ***,this study reveals the unique function of CoSe_(2),which can significantly promote oxygen adsorption,work as an electron sink and accelerate the generation of$O2-,thereby improving the selectivity toward xylonic acid over other *** work provides useful insights into the design of selective photocatalysts by engineering g-C_(3)N_(4)for biomass high-value utilization.

关键词： Biomass photooxidation Hemicelluloses Xylose g-C_(3)N_(4) Xylonic acid

Measure Complexity and Rigid Systems

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Acta Mathematica Sinica,English Series 2022年第1期38卷 68-84页

作者： Wen HUANG run Ju WEI Tao YU xiao Min ZHOU CAS Wu Wen-Tsun Key Laboratory of Mathematics School of Mathematical SciencesUniversity of Science and Technology of ChinaHefei 230026P.R.China Department of Mathematics Shantou UniversityShantou 515063P.R.China Department of Mathematics Huazhong University of Science and TechnologyWuhan 430074P.R.China

In this paper we introduce two metrics:the max metric d_(n,q)and the mean metric d_(n,q).We give an equivalent characterization of rigid measure preserving systems by the two *** turns out that an invariant measureμon a topological dynamical system(X,T)has bounded complexity with respect to d_(n,q)if and only ifμhas bounded complexity with respect to d_(n,q)if and only if(X,B_X,μ,T)is *** also obtain computation formulas of the measure-theoretic entropy of an ergodic measure preserving system(*** topological entropy of a topological dynamical system)by the two metrics dn,q and dn,q.

关键词： Rigid system entropy bounded complexity

Research,application and development of inorganic binder for casting process

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China Foundry 2024年第5期21卷 461-475页

作者： xiao-long Gong Sheng-li Hu zi-tian Fan State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

Inorganic binder used in casting process has the advantages of low odor,labor-friendly conditions,and relatively low cost,which is one of the main development directions for casting molding materials in the ***,compared to organic binders(such as resin binders),inorganic binders exhibit lower bonding strength and are more sensitive to environmental *** sensitivity poses challenges,particularly in the reclamation of used sand,thus limiting their broader *** this paper,the research and application status of inorganic binders(mainly silicate inorganic binders)and their curing methods are *** addition,the research and application of phosphate inorganic binders and 3D printing inorganic binders that are being developed are ***,a detailed comparative analysis is conducted on the challenging issue of“reclamation for used sand”in the application of inorganic ***,the development direction of inorganic binders is clarified.

关键词： inorganic binder silicate system phosphate system 3D printing used sand reclamation development trend

Unveiling an ancient whole-genome duplication event in Stentor,the model unicellular eukaryotes

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Science China Life Sciences 2025年

作者： Weibo Zheng Chao Li Zhaorui Zhou xiao Chen Michael Lynch Ying Yan School of Life Sciences Ludong University Key Laboratory of Evolution & Marine Biodiversity (Ministry of Education) and Institute of Evolution & Marine Biodiversity Ocean University of China Biodesign Center for Mechanisms of Evolution Arizona State University Marine College Shandong University

Whole-genome duplication(WGD) events are widespread across eukaryotes and have played a significant role in moulding the genetic architectures of diverse organisms. In the present study, the newly sequenced genome of a giant ciliated protist, Stentor roeselii, provides an opportunity for the analysis of the collinearity and retention of reciprocal best-hit genes between two Stentor species. As a main result, we have unveiled a previously undetected ancient WGD event shaping the genome of its congener, Stentor coeruleus, a model protist used in cytological and evolutionary studies. Genomes of two congeners, S. coeruleus and S. roeselii, are compared and analyzed, revealing that:(i)the former exhibits a much higher retention rate of colinear-gene pairs(28%) than does S. roeselii, and in S. coeruleus, 75% of genes that have a RBH hit in S. roeselii, have paralogs with high amino-acid identity, consistent with a WGD event in the lineage leading to S. coeruleus;(ii) the S. roeselii genome possesses extremely short intergenic regions, implying that the lengths of intergenic regions are under strong selection;(iii) the unique characteristics of introns may have been shaped in the common ancestor of heterotrichs;(iv) gene families that play a role in activities of multiple protein kinases and voltage-gated ion channels expanded rapidly in the ancestor of both taxa, possibly relating to the remarkable regenerative ability in Stentor. This study offers new insights into the evolutionary dynamics of ciliate genomes,with implications for understanding of the processes underlying the evolution of genomic complexity.

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Rise of β-furanosyl ribonucleosides as the extant RNA component facilitated by simple divalent transition-metal minerals

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Science China Chemistry 2025年

作者： Qianqian Chen Haoxing Xu Bingyue Zhao Yeersen Patehebieke Zerun Zhao xiao Wang School of Chemistry and Chemical Engineering Nanjing University Frontiers Science Center for Critical Earth Material Cycling Nanjing University

The selective nucleoside synthesis through direct condensation between nucleobase and unactivated sugar in aqueous media has long been a formidable obstacle for the early chemical transformations hypothesized to construct the RNAWorld, due to product complexity and the low selectivity of the desired isomer. The preference of β-furanoside, the extant RNA component, has never been documented. Here we report an aqueous ribosylation mediated by divalent transition-metal ions, which unprecedentedly enhances the selectivity of furanosyl ribonucleosides as opposed to the traditionally predominating pyranosyl ones, with the furanoside/pyranoside ratio reaching up to 9/1. Furthermore, β-furanoside stands out for the first time as the most prevalent isomer in the presence of zinc and ammonium salts. The mechanism of this selectivity is elucidated with density functional theory calculations. The selectivity for β-furanoside can be further elevated via the adsorption on a zinc mineral. These findings exhibit as the first example that the selection of nucleosides with the desired, canonical configuration might be completed in the early stage of the RNA-forming process as opposed to later evolution, promoted by simple and widespread transition-metal minerals. The study may also find its value in synthetic chemistry as a guideline for developing a sustainable and selective glycosylation process.

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Development of a general circumferentially nonuniform heat transfer fuel rod model for subchannel analysis and application to helical fuel rods

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Science China Technological Sciences 2025年

作者： Junsen FU Junlong LI xiaowen WANG Qi ZHANG Yao xiao Hanyang GU School of Mechanical Engineering Shanghai Jiao Tong University Key Laboratory of Nuclear Power Systems and Equipment of the Ministry of Education Shanghai Jiao Tong University National Key Laboratory of Nuclear Reactor Technology Nuclear Power Institute of China State Key Laboratory of Nuclear Power Safety Technology and Equipment Shanghai Jiao Tong University

The subchannel analysis method is one of the most crucial transient safety analysis methods in the thermal design of nuclear reactors. The nonuniformity of circumferential heat transfer is slight in conventional pressurized water reactor (PWR)cores, but it is significant in advanced reactors with wire-wrapped or helical fuel rods. Predicting circumferentially nonuniform heat transfer behavior can be challenging owing to the complex geometry of helical fuel rods. In this study, a general circumferentially nonuniform heat transfer fuel rod (GCNF) model is developed to predict the fuel central temperature and circumferential heat flux and wall temperature. This model incorporates a refined two-dimensional fuel conduction model and circumferential nonuniform shape factor, addressing the dual factors contributing to the circumferential nonuniformity of helical fuel rods. An empirical correlation for the nonuniform shape factor is developed based on the computational fluid dynamics (CFD) results, and it is implemented to the subchannel code. The newly developed model is applied to a helical fuel annulus and validated by comparing the prediction results with CFD data. The maximum wall temperature predicted by the code is 1.15°C lower than the value calculated through CFD. In terms of the heat flux, the maximum value at the inner corner is22 kW lower than that obtained from the CFD prediction. The accurate prediction of circumferentially nonuniform heat transfer in helical fuel, concerning the surface heat flux and cladding temperature, addresses existing shortcomings in helical fuel subchannel analysis methods. Additionally, the capability to predict the fuel central temperature is essential for the safety analysis to determine whether fuel rods are melting. The generality of the model framework allows it to be used for the prediction of circumferential nonuniform heat transfer behavior in other types of fuel assemblies.

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