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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第10期14卷 760-766页

作者： Li-yan DAI qiu-long shi Jing ZHANG Xiao-zhong WANG Ying-qi CHEN Department of Chemical and Biological Engineering Zhejiang University

Solubility of 2-amino-6-chloropurine in Mitsunobu solvents could be significantly improved after its exocyclic amino group is protected via *** bis-Boc protected 2-amino-6-chloropurine also shows excellent activity and N9 selectivity in the coupling with various alcohols by a Mitsunobu ***,a new practical and efficient method is established for the synthesis of penciclovir(PCV) from bis-Boc-2-amino-6-chloropurine 9 and the side chain of 5-(2-hydroxyethyl)-2,2-dimethyl-1,3-dioxane 5—the latter being a more easily prepared cyclic precursor of the diacetate side chain used in the conventional *** coupling of 9 with 5 proceeded regioselectively at a N9 position of purine derivative for a good yield under Mitsunobu conditions.

关键词： 2-amino-6-chloropurine Mitsunobu reaction bis-Boc protection Penciclovir(PCV)

Enhanced service stability and thermoelectric performance in Cu_(2)−δSebased composites

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Science China Materials 2024年第7期67卷 2369-2370页

作者： Pengfei qiu Xun shi State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China

Thermoelectric(TE)materials can directly convert the industrial waste heat into useful electricity based on the Seebeck effect,providing a promising way to tackle the environmental pollution and global energy crisis[1].In the past several decades,many new high-performance TE materials have been discovered to enrich the TE *** them,Cu_(2)−δSe-based TE materials,which are in line with the“phonon-liquid electron-crystal”concept,have sparked widespread interest due to the high TE figure-of-merit(ZT)and the combination of elements that are nontoxic and earth-abundant[2].In 2012,Liu et al.[3]reported a ZT of 1.5 at 1000 K in the stoichiometric Cu_(2)*** alloying S at the Se-site,the ZT was enhanced to around 2.0 at 1000 K[4].Via incorporating carbon nanotubes,the ZT was further enhanced to 2.4 at 1000 K[5].Moreover,Yang et al.[6]and Zhou et al.[7]reported that the ZT of Cu_(2)Se/BiCuSeO composites can reach 2.7–2.8 around 1000 K.

关键词： composites BiCuSeO performance

Effect of Modulus Heterogeneity on the Equilibrium Shape and Stress Field ofαPrecipitate in Ti-6Al-4V

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 1017-1028页

作者： Di qiu Rongpei shi Materials Genome Institute Shanghai UniversityShanghai200444China School of Materials Science and Engineering Harbin Institute of TechnologyShenzhen518055China Shanghai Frontier Science Center of Mechanoinformatics Shanghai UniversityShanghai200444China Zhejiang Laboratory Hangzhou311100China

For media with inclusions(e.g.,precipitates,voids,reinforcements,and others),the difference in lattice parameter and the elastic modulus between the matrix and inclusions cause stress concentration at the *** stress fields depend on the inclusions’size,shape,and distribution and will respond instantly to the evolving *** study develops a phase-field model concerningmodulus *** effect of modulus heterogeneity on the growth process and equilibrium state of theαplate in Ti-6Al-4V during precipitation is ***αprecipitate exhibits strong anisotropy in shape upon cooling due to the interplay of the elastic strain and interfacial *** calculated orientation of the habit plane using the homogeneous modulus ofαphase shows the smallest deviation fromthat of the habit plane observed in the experiment,compared to the case where the homogeneous modulus ofβphase is *** addition,the equilibrium volume ofαphase within the systemusing homogeneousβmodulus exhibits the largest dependency on the applied *** stress fields across theα/βinterface are further calculated under the assumption of modulus heterogeneity and compared to those using homogeneous modulus of eitherαorβ*** study provides an essential theoretical basis for developing mechanics models concerning systems with heterogeneous structures.

关键词： Elastic heterogeneity habit plane stress field titanium phase-field simulation

Electronic and Thermoelectric Properties in SnS-Nanoribbon-Based Heterojunctions

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Chinese Physics Letters 2024年第9期41卷 63-68页

作者： Kai-Bo Zhang shi-Hua Tan Xiao-Fang Peng Meng-qiu long Hunan Province Key Laboratory of Materials Surface or Interface Science and Technology Central South University of Forestry and TechnologyChangsha 410004China School of Physics and Electronics Central South UniversityChangsha 410083China

As an earth-abundant and environmentally friendly material,tin sulfide(SnS)is not only a high-performance photovoltaic material,but also a new promising thermoelectric *** extensive research on the thermoelectric properties of this material in recent years,the room-temperature thermoelectric figure of merit(ZT)of SnS has not been broke through 2[2022 *** Mater.651143].In this work,based on a combination of density functional theory and non-equilibrium Green’s function method,the electronic and thermoelectric properties in SnS-nanoribbon-based heterojunctions are *** results show that although SnS nanoribbons(SNSNRs)with zigzag edges(ZSNSNRs)and armchair edges(ASNSNRs)both have semiconductor properties,the bandgaps of ASNSNRs are much wider than those of ZSNSNRs,which induces much wider conductance gaps of𝑁-ASNSNR(N𝑁is the number of tin-sulfide lines across the ribbon width)).In the positive energy region,the ZT peaks of𝐿L-SNS-Au are much larger than those of𝐿L-SNS-GNR(L𝐿represents the number of longitudinal repeating units of SNSNR in the scattering region).While in the positive energy region,the ZT peaks of𝐿-SNSGNR are larger than those of𝐿-*** calculations reveal that the figure of merit will be over 3.7 in L-SNS-Au and 2.2 in𝐿L-SNS-GNR at room temperature,and over 4 in𝐿L-SNS-Au and 2.6 in𝐿L-SNS-GNR at 500 K.

关键词： material. sulfide ribbon

A low-power Bluetooth-based wireless sensor network and its global confliction-solving impact localization method

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Chinese Journal of Aeronautics 2024年第1期37卷 153-161页

作者： Yuanjia WANG Lei qiu Qiyun XU Liming shi College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Electrical and Electronic Engineering University of EdinburghEdinburgh EH89YLUK

During the whole service lifetime of aircraft structures with composite materials,impacts are inevitable and can usually cause severe but barely visible *** the occurrences of impact are random and unpredictable,it is a hotspot direction to develop an online impact monitoring system that can meet strict limitations of aerospace applications including small size,light weight,and low power ***(PZT)sensor,being able to generate impact response signals with no external power and cover a large-scale structure with only a small amount of them,is a promising ***,for real systems,networks with multiple nodes are normally required to monitor large-scale structures in a global way to identify any impact localization confliction,yet the existing studies are mostly evaluated with single nodes instead of ***,in this paper,based on a new low-power node designed,a Bluetooth-based digital impact monitoring PZT sensor network is proposed for the first time with its global confliction-solving impact localization *** of the system as a network are researched and analyzed on a complex real aircraft wing box for a global confliction-solving impact localization,showing a satisfying high accuracy.

关键词： Bluetooth-based low-power design Confliction-solving evaluation Complex composites Piezoelectric sensors Wireless impact monitoring network

Effects of rafting on the meso deformation and fracture behaviour of a Ni-based single crystal superalloy at room temperature: In-situ observation and simulation

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Science China(Technological Sciences) 2024年第7期67卷 2133-2146页

作者： TAN long YANG XiaoGuang shi DuoQi FAN YongSheng shi Yi School of Energy and Power Engineering Beihang UniversityBeijing 102206China Research Institute of Aero-Engine Beihang UniversityBeijing 102206China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 102206China School of Materials Science&Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Microstructural rafting of Ni-based single-crystal(SC) superalloys is inevitable at elevated temperatures during long-term service with mechanical loading, which significantly affects the mechanical behaviour of the material. In this study, the effects of rafting on the mesodeformation and fracture behaviour of a Ni-based SC superalloy under cyclic and tensile loads were investigated using in situ scanning electron microscopy(SEM), digital image correlation(DIC), and crystal plasticity finite element method(CP-FEM) simulations. The results indicated that the tensile strength decreased significantly in the rafted specimens. In the cyclic tests, both the virgin and rafted specimens showed an increase in the maximum shear strain with cycle number. The interaction of cross-slip bands was captured by in situ SEM-DIC around the micro-notch of the virgin specimens during the tensile test, while a more homogeneous local deformation field was observed in the rafting specimens. In addition,the fracture behaviour was strongly influenced by the rafting morphology. The crack exhibited instantaneous and long-range fracture features along the octahedral plane as it propagated in the rafting specimen, whereas it deflected over a short distance between the crystallographic planes at an early stage in the virgin specimen, which is consistent with the CP-FEM ***, the CP-FEM results for the crack initiation direction on(111) dominant slip plane were consistent with the in situ SEM observations.

关键词： in-situ SEM-DIC Ni-based SC superalloys microstructural rafting deformation crack path CP-FEM

Metallurgy and Solidification Microstructure Control of Fusion-Based Additive Manufacturing Fabricated Metallic Alloys:A Review

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 29-53页

作者： Qiang Li Xing-Ran Li Bai-Xin Dong Xiao-long Zhang shi-Li Shu Feng qiu Lai-Chang Zhang Zhi-Hui Zhang Key Laboratory of Bionic Engineering(Ministry of Education) and College of Bionic Science and EngineeringJilin UniversityChangchun130022China Institute of Structured and Architected Materials Liaoning Academy of MaterialsShenyang110167China Key Laboratory of Automobile Materials Ministry of Education and Department of Materials Science and EngineeringJilin UniversityChangchun130025China School of Mechanical and Aerospace Engineering Jilin UniversityChangchun130025China School of Engineering Edith Cowan University270 Joondalup DriveJoondalupPerthWA6027Australia

The metal-based additive manufacturing(AM),also referred to as metal 3D printing,has drawn particular interest because it enables direct creation,aided by computationally-directed path design,of intricate components with site-specific compositions and geometrical requirements as well as low buy-to-fly *** the last two decades,the objective of this revolutionary technology has been shifting from only“rapid prototyping”to advanced manufacturing of special high-end products or devices,which,in many aspects,outperform conventional manufacturing *** fusion-based AM,significant progress has been achieved in understanding the processing window of macroscopic scales,non-equilibrium metallurgy of mesoscale scales,and grain evolution of microscopic *** the versatile capacity of AM facilitates new avenues for discovering advanced materials and structures,their potential has still not been fully *** the unique non-equilibrium solidification during the AM process,coarse columnar grains with strong textures are usually developed along the build direction,which downgrades the mechanical *** push the limits of this digital manufacturing,this review attempts to provide in-depth and comprehensive overviews of the recent progress in understanding the evolution and control of the as-built microstructure that has been made recently and the challenges encountered during the AM process.

关键词： Additive manufacturing Temperature field Microstructure control Nanoparticles Functionally graded materials

Satellite anomaly detection based on reconstruction discrepancy theory utilizing a new dual-branch reconstruction model

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Science China Technological Sciences 2024年第10期67卷 3294-3307页

作者： ZHAO HaoTian qiu shi LIU Ming CAO XiBin Research Center of Satellite Technology School of AstronauticsHarbin Institute of Technology

To enhance the accuracy of deep learning methods based on reconstruction discrepancy in satellite anomaly detection tasks, this study proposes a dual-branch reconstruction model(DBRM) and designs a comprehensive satellite anomaly detection framework around this model. Firstly, we introduce the temporal-channel mixer(TC-Mixer) module, which mainly comprises a self-attention layer for capturing long-range temporal dependencies in telemetry data, and two types of feed-forward networks(FFN) for extracting complex patterns in the temporal and channel dimension of telemetry data. This design endows the TC-Mixer module with robust capabilities for extracting complicated dependencies in telemetry data. Secondly, with the TC-Mixer module as the main component, we designed the DBRM. This model utilizes a shared latent representation layer, allowing the regeneration branch and forecasting branch of the DBRM to share most of the feature extraction network architecture. This approach significantly enhances the model's regression accuracy while reducing computational complexity. Thirdly, using the DBRM as the core network model, we devised a comprehensive satellite anomaly detection framework. This includes an anomaly criterion that considers the reconstruction discrepancy of both the regeneration and forecasting branches, the peak-over-threshold(POT) method for anomaly thresholding, and the MIC-based feature engineering method, etc. Finally, we conducted comparative experiments with several SOTA anomaly detection algorithms on two public and one private satellite anomaly detection datasets. The experimental results validate the effectiveness and superiority of our proposed method.

关键词： anomaly detection reconstruction discrepancy dual-branch reconstruction model (DBRM) satellite telemetry data time series

Hyperspectral Image Based Interpretable Feature Clustering Algorithm

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Computers, Materials & Continua 2024年第5期79卷 2151-2168页

作者： Yaming Kang PeishunYe Yuxiu Bai shi qiu School of Information Engineering Yulin UniversityYulin719000China Key Laboratory of Spectral Imaging Technology CAS Xi’an Institute of Optics and Precision MechanicsChinese Academy of SciencesXi’an710119China

Hyperspectral imagery encompasses spectral and spatial dimensions,reflecting the material properties of *** application proves crucial in search and rescue,concealed target identification,and crop growth *** is an important method of hyperspectral *** vast data volume of hyperspectral imagery,coupled with redundant information,poses significant challenges in swiftly and accurately extracting features for subsequent *** current hyperspectral feature clustering methods,which are mostly studied from space or spectrum,do not have strong interpretability,resulting in poor comprehensibility of the ***,this research introduces a feature clustering algorithm for hyperspectral imagery from an interpretability *** commences with a simulated perception process,proposing an interpretable band selection algorithm to reduce data *** this,amulti-dimensional clustering algorithm,rooted in fuzzy and kernel clustering,is developed to highlight intra-class similarities and inter-class *** optimized P systemis then introduced to enhance computational *** system coordinates all cells within a mapping space to compute optimal cluster centers,facilitating parallel *** approach diminishes sensitivity to initial cluster centers and augments global search capabilities,thus preventing entrapment in local minima and enhancing clustering *** conducted on 300 datasets,comprising both real and simulated *** results show that the average accuracy(ACC)of the proposed algorithm is 0.86 and the combination measure(CM)is 0.81.

关键词： Hyperspectral fuzzy clustering tissue P system band selection interpretable

Pressure transient characteristics of non-uniform conductivity fractured wells in viscoelasticity polymer flooding based on oil-water two-phase flow

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Petroleum Science 2024年第1期21卷 343-351页

作者： Yang Wang Jia Zhang shi-long Yang Ze-Xuan Xu shi-Qing Cheng National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China

Polymer flooding in fractured wells has been extensively applied in oilfields to enhance oil *** contrast to water,polymer solution exhibits non-Newtonian and nonlinear behavior such as effects of shear thinning and shear thickening,polymer convection,diffusion,adsorption retention,inaccessible pore volume and reduced effective ***,the flux density and fracture conductivity along the hydraulic fracture are generally non-uniform due to the effects of pressure distribution,formation damage,and proppant *** this paper,we present an oil-water two-phase flow model that captures these complex non-Newtonian and nonlinear behavior,and non-uniform fracture characteristics in fractured polymer *** hydraulic fracture is firstly divided into two parts:high-conductivity fracture near the wellbore and low-conductivity fracture in the far-wellbore section.A hybrid grid system,including perpendicular bisection(PEBI)and Cartesian grid,is applied to discrete the partial differential flow equations,and the local grid refinement method is applied in the near-wellbore region to accurately calculate the pressure distribution and shear rate of polymer *** combination of polymer behavior characterizations and numerical flow simulations are applied,resulting in the calculation for the distribution of water saturation,polymer concentration and reservoir *** with the polymer flooding well with uniform fracture conductivity,this non-uniform fracture conductivity model exhibits the larger pressure difference,and the shorter bilinear flow period due to the decrease of fracture flow ability in the far-wellbore *** field case of the fall-off test demonstrates that the proposed method characterizes fracture characteristics more accurately,and yields fracture half-lengths that better match engineering reality,enabling a quantitative segmented characterization of the near-wellbore section with high fracture conductivity and th

关键词： Polymer flooding Non-Newtonian fluid Non-uniform fracture conductivity Two-phase flow Pressure transient analysis