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Thermodynamic modeling of Fe-C-Mn-Si alloys

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Journal of Iron and Steel Research International 2017年第2期24卷 190-197页

作者： wei-sen zheng Xiao-gang Lu Yan-lin He Lin Li School of Materials Science and Engineering Shanghai University Shanghai 200444 China Department of Materials Science and Engineering KTH Royal Institute of Technology Stockholm 10044 Sweden State Key Laboratory of Advanced Special Steel Shanghai University Shanghai 200072 China

The thermodynamic database of the Fe C Mn-Si system has been developed in the framework of the CALPHAD approach. The sub-ternary systems have been carefully evaluated and revised based on available experimental data. A satisfactory description of the liquid phase in the Fe C-Si system has been obtained. The C Mn Si system was assessed treating the liquid phase as a substitutional solution. Phase equilibria in the C- Mn-Si system, especially those involving the liquid phase, can be well described. Based on the extrapolation of the experimental data in the quaternary system, the Fe Mn Si system has been modified to agree well with experimental data at high temperatures. The comparison between the calculated and measured phase transformation tempera tures confirms the reliability of the present quaternary database. Additionally, the solidification process of Fe-0. 16C-1. 5Mn-1. 5Si （wt. %） alloy was simulated by using the thermodynamic database developed.

关键词： Fe-C-Mn-Si alloy Thermodynamic mode CALPHAD Solidification Partial equilibrium

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Experimental study of phase equilibria on Co-Fe-rich side of Co-Al-Fe system

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Journal of Iron and Steel Research International 2020年第6期27卷 673-680页

作者： Jing-jing Wang wei-sen zheng Xiao-gang Lu Yan-lin He Qing-rong Yao Jiang Wang School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Materials Genome Institute Shanghai UniversityShanghai200444China State Key Laboratory of Advanced Special Steel Shanghai UniversityShanghai200444China School of Materials Science and Engineering Guilin University of Electronic TechnologyGuilin 541004GuangxiChina

Despite various studies on Co-Al-Fe ternary system, its phase equilibria are still in doubt. Phase equilibria, magnetic transition and bcc_A2/bcc_B2 order-disorder transformation at the Co-Fe-rich side of the Co-Al-Fe alloys were carefully investigated by means of electron probe microanalysis (EPMA), X-ray diffraction (XRD) and differential scanning calo-rimetry. The equilibrium phases and their compositions were determined by 18 alloy samples annealed at 900, 1000, 1100 and 1200℃ for 528, 336, 168 and 96h, respectively, followed by quenching. However, by adopting the above traditional method, bcc_A2 and fcc_A1 phases are difficult to be distinguished through XRD analysis at room temperature due to the martensitic transformation of fcc_A1 phase during quenching. For this reason, high-temperature insitu XRD technique was utilized to correctly establish the phase relationships among bcc_A2, bcc_B2 and fcc_A1 phases. The phase transformation between bcc_A2 and B2 phases was determined to be second order instead of first order at temperatures higher than 900℃. The equilibrium phases and compositions were further confirmed by fabricating 16 diffusion couples together with EPMA. Meanwhile, using three-dimensional differential scanning calorimetry method, bcc_A2/B2 and ferro-/paramagnetic transi-tions were determined with high accuracy.

关键词： Co-Al-Fe system Phase equilibrium Martensitic transformation Order-disorder transition

Predictive factors and model validation of post-colon polyp surgery Helicobacter pylori infection

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World Journal of Gastrointestinal Surgery 2024年第1期16卷 173-185页

作者： zheng-sen Zhang Health Management Center Affiliated Hospital of Shaoxing University(Shaoxing Municipal Hospital)Shaoxing 312000Zhejiang ProvinceChina

BACKGROUND Recently,research has linked Helicobacter pylori(***)stomach infection to colonic inflammation,mediated by toxin production,potentially impacting colorectal cancer *** To investigate the risk factors for post-colon polyp surgery,*** infection,and its correlation with pathologic *** Eighty patients who underwent colon polypectomy in our hospital between January 2019 and January 2023 were retrospectively *** were then randomly split into modeling(n=56)and model validation(n=24)sets using *** modeling cohort was divided into an ***-infected group(n=37)and an ***-uninfected group(n=19).Binary logistic regression analysis was used to analyze the factors influencing the occurrence of *** infection after colon polyp surgery.A roadmap prediction model was established and ***,the correlation between the different pathological types of colon polyps and the occurrence of *** infection was analyzed after colon polyp *** Univariate results showed that age,body mass index(BMI),literacy,alcohol consumption,polyp pathology type,high-risk adenomas,and heavy diet were all influential factors in the development of *** infection after intestinal *** multifactorial logistic regression analysis showed that age,BMI,and type of polyp pathology were independent predictors of the occurrence of *** infection after intestinal *** area under the receiver operating characteristic curve was 0.969[95%confidence interval(95%CI):0.928–1.000]and 0.898(95%CI:0.773–1.000)in the modeling and validation sets,*** slope of the calibration curve of the graph was close to 1,and the goodness-of-fit test was P>0.05 in the two *** decision analysis curve showed a high rate of return in both *** results of the correlation analysis between different pathological types and the occurrence of *** infection after colon polyp surgery showed that hyperplastic

关键词： Colon polyps Helicobacter pylori Risk factors Pathologic type Columnar graphic modeling

On-surface synthesis and characterization of polyynic carbon chains

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National Science Review 2024年第3期11卷 192-199页

作者： Wenze Gao wei zheng Luye Sun Faming Kang zheng Zhou wei Xu Interdisciplinary Materials Research Center School of Materials Science and Engineering Tongji University

Carbyne, an elusive sp-hybridized linear carbon allotrope, has fascinated chemists and physicists for decades. Due to its high chemical reactivity and extreme instability, carbyne was much less explored in contrast to the sp2-hybridized carbon allotropes such as graphene. Herein, we report the on-surface synthesis of polyynic carbon chains by demetallization of organometallic polyynes on the Au（111） surface;the longest one observed consists of ～60 alkyne units（120 carbon atoms）. The polyynic structure of carbon chains with alternating triple and single bonds was unambiguously revealed by bond-resolved atomic force microscopy. Moreover, an atomically precise polyyne, C14, was successfully produced via tip-induced dehalogenation and ring-opening of the decachloroanthracene molecule(C14Cl10) on a bilayer NaCl/Au（111） surface at 4.7 K, and a band gap of 5.8 eV was measured by scanning tunnelling spectroscopy,in a good agreement with the theoretical HOMO–LUMO gap（5.48 eV）.

关键词： polyyne scanning probe microscopy carbon allotrope on-surface synthesis organometallic polyyne

Accurately tracking hypersonic gliding vehicles via an LEO mega-constellation in relay tracking mode

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Journal of Systems Engineering and Electronics 2024年第1期35卷 211-221页

作者： LI Zhao WANG Yidi zheng wei College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

In order to effectively defend against the threats of the hypersonic gliding vehicles(HGVs),HGVs should be tracked as early as possible,which is beyond the capability of the ground-based *** benefited by the developing megaconstellations in low-Earth orbit,this paper proposes a relay tracking mode to track HGVs to overcome the above *** whole tracking mission is composed of several tracking intervals with the same *** each tracking interval,several appropriate satellites are dispatched to track the *** that are planned to take part in the tracking mission are selected by a new derived observability *** tracking performances of the proposed tracking mode and the other two traditional tracking modes,including the stare and track-rate modes,are compared by *** results show that the relay tracking mode can track the whole trajectory of a HGV,while the stare mode can only provide a very short tracking ***,the relay tracking mode achieve higher tracking accuracy with fewer attitude controls than the track-rate mode.

关键词： target tracking mega-constellation hypersonic gliding vehicle(HGV) sensor selection observability analysis

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Improving the spaceborne GNSS-R altimetric precision based on the novel multilayer feedforward neural network weighted joint prediction model

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Defence Technology（防务技术） 2024年第2期32卷 271-284页

作者： Yiwen Zhang wei zheng Zongqiang Liu Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100094China China Academy of Aerospace Science and Innovation Beijing 100176China State Key Laboratory of Space-Ground Integrated Information Technology Beijing Institute of Satellite Information EngineeringBeijing 100194China

Global navigation satellite system-reflection(GNSS-R)sea surface altimetry based on satellite constellation platforms has become a new research direction and inevitable trend,which can meet the altimetric precision at the global scale required for underwater *** present,there are still research gaps for GNSS-R altimetry under this mode,and its altimetric capability cannot be specifically ***,GNSS-R satellite constellations that meet the global altimetry needs to be ***,the matching precision prediction model needs to be established to quantitatively predict the GNSS-R constellation altimetric ***,the GNSS-R constellations altimetric precision under different configuration parameters is calculated,and the mechanism of the influence of orbital altitude,orbital inclination,number of satellites and simulation period on the precision is analyzed,and a new multilayer feedforward neural network weighted joint prediction model is ***,the fit of the prediction model is verified and the performance capability of the model is tested by calculating the R2 value of the model as 0.9972 and the root mean square error(RMSE)as 0.0022,which indicates that the prediction capability of the model is ***,using the novel multilayer feedforward neural network weighted joint prediction model,and considering the research results and realistic costs,it is proposed that when the constellation is set to an orbital altitude of 500 km,orbital inclination of 75and the number of satellites is 6,the altimetry precision can reach 0.0732 m within one year simulation period,which can meet the requirements of underwater navigation precision,and thus can provide a reference basis for subsequent research on spaceborne GNSS-R sea surface altimetry.

关键词： GNSS-R satellite constellations Sea surface altimetric precision Underwater navigation Multilayer feedforward neural network

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High-Order Decoupled and Bound Preserving Local Discontinuous Galerkin Methods for a Class of Chemotaxis Models

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Communications on Applied Mathematics and Computation 2024年第1期6卷 372-398页

作者： wei zheng Yan Xu School of Mathematical Sciences University of Science and Technology of ChinaHefei230026AnhuiChina

In this paper,we explore bound preserving and high-order accurate local discontinuous Galerkin(LDG)schemes to solve a class of chemotaxis models,including the classical Keller-Segel(KS)model and two other density-dependent *** use the convex splitting method,the variant energy quadratization method,and the scalar auxiliary variable method coupled with the LDG method to construct first-order temporal accurate schemes based on the gradient flow structure of the *** semi-implicit schemes are decoupled,energy stable,and can be extended to high accuracy schemes using the semi-implicit spectral deferred correction *** bound preserving DG discretizations are only worked on explicit time integration methods and are difficult to get high-order *** overcome these difficulties,we use the Lagrange multipliers to enforce the implicit or semi-implicit LDG schemes to satisfy the bound constraints at each time *** bound preserving limiter results in the Karush-Kuhn-Tucker condition,which can be solved by an efficient active set semi-smooth Newton *** numerical experiments illustrate the high-order accuracy and the effect of bound preserving.

关键词： Chemotaxis models Local discontinuous Galerkin(LDG)scheme Convex splitting method Variant energy quadratization method Scalar auxiliary variable method Spectral deferred correction method

Remote-controlled dexamethasone-duration on eye-surface with a micelle-magnetic nanoparticulate co-delivery system for dry eye disease

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Acta Pharmaceutica Sinica B 2024年第8期14卷 3730-3745页

作者： Qinxiang zheng Chaoxiang Ge Kexin Li Longxin Wang Xiaoyu Xia Xiao Liu Rashid Mehmood Jianliang Shen Kaihui Nan wei Chen sen Lin National Engineering Research Center of Ophthalmology and Optometry Eye HospitalWenzhou Medical UniversityWenzhou 325027China National Clinical Research Center for Ocular Diseases Eye HospitalWenzhou Medical UniversityWenzhou 325027China Zhejiang Engineering Research Center for Tissue Repair Materials Wenzhou InstituteUniversity of Chinese Academy of SciencesWenzhou 325000China School of Chemical Engineering UNSW SydneyHigh StreetBuilding E10KensingtonNSW 2052Australia Adult Cancer Program Lowy Cancer Research CentreUNSW SydneyCorner Botany&High StreetsKensingtonNSW 2052Australia

Dexamethasone(DEX)is used to treat ocular surface ***,regulating DEX duration in tears while preventing its absorption into the anterior chamber is critical for balancing its therapy effects and the side *** this study,a novel magnetic nanoparticle(MNP)-micelle(MC)codelivery system(MMDS)was *** MC moiety in the MMDS served as the carrier for DEX and the MNP part endowed the MMDS with magnetic-responsive *** extend its residency,the MMDS was magnetically attracted by an external magnet after instilling,which acted as a precorneal drug-depot enabling a sustainable release of DEX in *** combination of magnet treatment,the topical instillation of MMDS@DEX significantly prolonged the DEX-retention in tears and increased the DEX-concentration in the cornea and conjunctiva,as well as concurrently reduced the DEX-level in the aqueous humor,when compared with the commercial DEX eye drop *** combination of MMDS@DEX and magnet treatment exerted significantly better therapeutic effects against DED with smaller side effects than conventional treatments including DEX suspension,commercial DEX eye drops,as well as the MMDS@DEX treatment *** present work provided a new method for the effective delivery of DEX to ocular surface tissues while reducing its side effects,which will be beneficial to the treatments of a wide range of ocular surface diseases.

关键词： Magnetic nanoparticle Micelle Dexamethasone Eye drop Bioavailability Dry eye disease Cornea Conjunctiva

Joint Sample Position Based Noise Filtering and Mean Shift Clustering for Imbalanced Classification Learning

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Tsinghua Science and Technology 2024年第1期29卷 216-231页

作者： Lilong Duan wei Xue Jun Huang Xiao zheng School of Computer Science and Technology Anhui University of TechnologyMaanshan 243032China Institute of Artificial Intelligence Hefei Comprehensive National Science CenterHefei 230088China

The problem of imbalanced data classification learning has received much *** classification algorithms are susceptible to data skew to favor majority samples and ignore minority *** weighted minority oversampling technique(MWMOTE)is an effective approach to solve this problem,however,it may suffer from the shortcomings of inadequate noise filtering and synthesizing the same samples as the original minority *** this end,we propose an improved MWMOTE method named joint sample position based noise filtering and mean shift clustering(SPMSC)to solve these ***,in order to effectively eliminate the effect of noisy samples,SPMsC uses a new noise filtering mechanism to determine whether a minority sample is noisy or not based on its position and distribution relative to the majority *** that MWMOTE may generate duplicate samples,we then employ the mean shift algorithm to cluster minority samples to reduce synthetic replicate ***,data cleaning is performed on the processed data to further eliminate class *** on extensive benchmark datasets demonstrate the effectiveness of SPMsC compared with other sampling methods.

关键词： imbalanced data classification oversampling noise filtering clustering