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China Foundry 2022年第5期19卷 411-418页

作者： Peng Peng Jin-mian Yue An-qiao Zhang Jia-tai Wang Jiang-lei Fan School of Physics and Electronic Information Engineering Qinghai Normal UniversityXining 753000China School of Materials and Energy Lanzhou UniversityLanzhou 730000China Northwest Rare Metal Materials Research Institute Shizuishan 753099NingxiaChina Shanxi Taigang Stainless Steel Co. Ltd.Taiyuan 030003China School of Mechanical and Electrical Engineering Zhengzhou University of Light IndustryZhengzhou 450000China

The morphologies of intermetallic phases(IMCs)during directional solidification of the Sn-Cu(L+Cu_(3)Sn→Cu_(6)Sn_(5))and Sn-Co(L+CoSn→CoSn_(2))peritectic systems were analyzed.The primary Cu_(3)Sn and peritectic Cu_(6)Sn_(5)phases in Sn-Cu alloy are IMCs whose solubility ranges are narrow,while both the primary CoSn and peritectic CoSn_(2)phases in Sn-Co alloy are IMCs whose solubility ranges are nil in equilibrium condition.The experimental results before acid corrosion shows that the dendritic morphology of both the Cu_(6)Sn_(5)and CoSn_(2)phases can be observed.The investigation on the local dendritic morphology after deep acid corrosion shows that these dendrites are composed of small sub-structures with faceted feature.Faceted growth of the primary Cu_(3)Sn and CoSn phases is also confirmed,and a faceted to non-faceted transition in their morphologies is observed with increasing growth velocities.Further analysis shows that the dendritic morphology is formed in the solidified phases whose solubility range is larger during peritectic solidification.

关键词： intermetallic compound phase peritectic alloy directional solidification solubility range sub-structure

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结合自适应保真项的各向异性扩散模型

计算机工程与应用 2016年第7期52卷 206-209页

作者：彭杨重庆三峡学院数学与统计学院重庆404100

为了在去除噪声的同时,对图像更好的保真,在各向异性扩散模型的基础上,提出了结合自适应保真项的各向异性扩散模型。该模型能够很好地抑制边缘上的噪声和强噪声。实验结果表明,该模型不仅能有效去除噪声,而且对图像细节、边缘也能很好... 详细信息

为了在去除噪声的同时,对图像更好的保真,在各向异性扩散模型的基础上,提出了结合自适应保真项的各向异性扩散模型。该模型能够很好地抑制边缘上的噪声和强噪声。实验结果表明,该模型不仅能有效去除噪声,而且对图像细节、边缘也能很好的保真。

关键词： ROF模型自适应保真各向异性扩散图像去噪 P-M模型

Existence and Regularity of Solution of the Liquid^(4)He Model Coupling with an Applied Magnetic Field

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Acta Mathematicae Applicatae Sinica 2022年第2期38卷 497-511页

作者： Chen peng College of Mathematics Sichuan UniversityChengdu 610065China

In this paper,we derive a time-dependent Ginzburg-Landau model for liquid^(4)He coupling with an applied magnetic field basing on the Le Chatlier principle.We also obtain the existence and uniqueness of global weak solution for this model.In addition,by utilizing the regularity estimates for linear semigroup,we prove that the model possesses a global classical solution.

关键词： Ginzburg-Landau model liquid^(4)He existence uniqueness regularity semigroup of operator

Analysis on fluid permeability of dendritic mushy zone during peritectic solidification in a temperature gradient

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Journal of Materials Science & Technology 2021年第12期71卷 169-176页

作者： Peng Peng Jinmian Yue Anqiao Zhang Xudong Zhang Yuanli Xu Institute of Materials Science and Engineering Lanzhou UniversityLanzhou730000China School of Physical Science and Technology Lanzhou UniversityLanzhou730000China

Compared with the growing applications of peritectic alloys,none research on the fluid permeability K of dendritic network during peritectic solidification has been reported before.The fluid permeability K of dendritic network in the mushy zone during directional solidification of Sn-Ni peritectic alloy was investigated in this study.Examination on the experimental results demonstrates that both the temperature gradient zone melting(TGZM)and Gibbs-Thomson(G–T)effects have obvious influences on the morphology of dendritic network during directional solidification.This is realized through different stages of liquid diffusion within dendritic mushy zone by these effects during directional solidification.The TGZM effect is demonstrated to play a more important role as compared with the G–T effect during directional solidification.Besides,it is shown that the evolution of dendrite network is more complex during peritectic solidification due to the involvement of the peritectic phase.Through the specific surface SV,analytical expression based on the Carman–Kozeny model was proposed to analyze the fluid permeability of dendritic mushy zone in directionally solidified peritectic alloys.In addition,it is interesting to find a rise in permeability K after peritectic reaction in both theoretical predication and experimental results,which is different from that in other alloys.The theoretical predictions show that this rise in fluid permeability K after peritectic reaction is caused by the remelting/resolidification process on dendritic structure by the TGZM and G–T effects during peritectic solidification.

关键词： Alloys Diffusion behaviour Directional solidification Peritecticm icrostructures Solid/liquid interface

Multiple thermal events recorded in the Acasta Gneiss Complex:Evidence from in-situ dating of zircon, titanite, and apatite

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Science China Earth Sciences 2024年第3期67卷 673-686页

作者： Qingfeng MEI Jinhui YANG Jinfeng SUN Qiuli LI Shitou WU Xiaoxiao LING Peng Peng Hao WANG State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Computational Geodynamics University of Chinese Academy of SciencesBeijing 100049China

In-situ dating of the zircons, titanites, and apatites in the rock fragments of approximately 1 cm2in size from the Acasta Gneiss Complex was performed using secondary ion mass spectrometry or laser ablation inductively coupled plasma mass spectrometry to provide constraints on the thermal history of the Acasta Gneiss Complex. The zircons in these rock fragments typically exhibit multiple age populations, reflecting the presence of inherited zircons or the post-crystallization process of zircon overgrowth. Combined with previous studies, our zircon dating results reveal multiple magmatic events that occurred in the Acasta Gneiss Complex, specifically at >3.96, ~3.72, and ~3.57 Ga, respectively. A titanite Pb-Pb isochron age of2911±22 Ma(95% confidence level, MSWD=1.5) for sample AY199 is identified, consistent with the timing of the latest Archean magmatism in the Acasta Gneiss Complex. The titanite U-Pb ages for samples AC478 and AY066 are 1932±270 Ma(95% confidence level, MSWD=2.3) and 1813±45 Ma(95% confidence level, MSWD=2.3), respectively. The apatites in sample P090803-C exhibit a Pb-Pb isochron age of 1833±26 Ma(95% confidence level, MSWD=1.4). The apatite U-Pb ages for samples AC478, AY199, and AY066 are 1850±20 Ma(95% confidence level, MSWD=1.3), 1827±100 Ma(95% confidence level, MSWD=6.3), and 1807±58 Ma(95% confidence level, MSWD=3.9), respectively. Titanites in samples AC478 and AY066, as well as the apatites in all four investigated samples, show a uniform age(Pb-Pb or U-Pb age) of ~1.9–1.8 Ga,indicating U-Pb system reset in these minerals due to the Wopmay orogeny and documenting that the peak temperature condition associated with the Wopmay orogeny exceeded the apatite U-Pb closure temperature and approached or exceeded that of titanite.

关键词： Zircon Titanite Apatite Acasta Gneiss Complex Wopmay Orogen

Macrosegregation and thermosolutal convection-induced freckle formation in dendritic mushy zone of directionally solidified Sn-Ni peritectic alloy

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Journal of Materials Science & Technology 2021年第16期75卷 21-26页

作者： Peng Peng Anqiao Zhang Jinmian Yue Xudong Zhang Yuanli Xu Institute of Materials Science and Engineering Lanzhou UniversityLanzhou730000China School of Physical Science and Technology Lanzhou UniversityLanzhou730000China

Compared with the growing applications of peritectic alloy,none research on the freckle formation during peritectic solidification has been reported before.Observation on the dendritic mushy zone of Sn-36 at.%Ni peritectic alloy during directional solidification at different growth velocities shows that the freckles are formed in two different regions:region I before peritectic reaction and region II after peritectic reaction.In addition,more freckles can be observed at lower growth velocities.Examination on the experimental results demonstrates that both the temperature gradient zone melting(TGZM)and Gibbs-Thomson(G–T)effects have obvious influences on the morphology of dendritic network during directional solidification.The current theories onKI Rayleigh number Racharacterizing the thermosolutal convection of dendritic mushy zone to predict freckle formation through the maximum of Ra can only explain the existence of region I while the appearance of region II after peritectic reaction cannot be predicted.Thus,a new Rayleigh number RaP is proposed in consideration of evolution of dendritic mushy zone by both effects and peritectic reaction.Theoretical prediction of RaPalso shows a maximum after peritectic reaction in addition to that before peritectic reaction,thus,agreeing well with the freckle formation in region II.In addition,more severe thermosolutal convection can be predicted by the new Rayleigh number RaP at lower growth velocities,which further demonstrates the reliability of RaP in describing the dependence of freckle formation on growth velocity.

关键词： Directional solidification Thermosolutal convection Dendritic solidification Peritectic microstructures

What besides redox conditions? Impact of sea-level fluctuations on redox-sensitive trace-element enrichment patterns in marine sediments

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Science China Earth Sciences 2022年第10期65卷 1985-2004页

作者： Junwen peng Bureau of Economic Geology Jackson School of GeosciencesThe University of Texas at AustinAustinTexas 78713USA

Concentrations of redox-sensitive trace-element(RSTE) in marine shales have long been interpreted simply as redox proxies. However, the impact of other non-redox factors(e.g., sea-level fluctuation and seawater chemistry) on the enrichment of RSTE, especially molybdenum(Mo) and uranium(U), in sediments has been rarely reported. This study presents newly obtained RSTE datasets from the Upper Pennsylvanian organic-rich Cline Shale in the silled Midland Basin, U.S., to illustrate the influence of sea-level fluctuation on the authigenic accumulation of RSTE in marine sediments. A previously established transgressive-regressive sequence of the Cline Shale, a well-constrained high-amplitude glacio-eustatic fluctuation curve, and an accompanying episodic resupply of aqueous RSTE from the Panthalassic Ocean provide an ideal stratigraphic framework for determining the spatial and temporal variations of sediment RSTE enrichment patterns that responded to the episodic variations of seawater chemistry in this marginal silled paleomarine basin. Results suggest that although slightly higher median RSTE concentrations were observed in sediments from more reducing environments, the overall variation ranges of RSTE concentrations largely overlap among sediments deposited from a wide redox spectrum(from oxic to euxinic conditions) or different sea-level statuses in the Cline Shale. In contrast to the sediment RSTE enrichment patterns, the variations of sediment Mo/TOC and U/TOC ratios are coupled with glacio-eustatic fluctuation. The highest Mo/TOC and U/TOC ratios are commonly observed in sediments deposited during the highest relative sea-level(RSTE resupply), whereas the lowest Mo/TOC and U/TOC ratios usually appear in sediments deposited during the lowest relative sea-level(RSTE depletion). Our findings suggest that the benthic redox conditions recorded in sediment Mo and U concentrations can be greatly obscured and weakened by depleted aqueous Mo and U concentrations in highly restricted basins. Thus, the use of sediment Mo a

关键词： Molybdenum Uranium Glacio-eustatic fluctuation Pennsylvanian Cline Shale Midland Basin

Amino acid nutrition and metabolism in domestic cats and dogs

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畜牧与生物技术杂志:英文版 2023年第5期14卷 1777-1797页

作者： peng Li Guoyao Wu North American Renderers Association AlexandriaVirginia 22314USA Department of Animal Science Texas A&M UniversityCollege StationTX 77843USA

Domestic cats and dogs are carnivores that have evolved differentially in the nutrition and metabolism of amino acids.This article highlights both proteinogenic and nonproteinogenic amino acids.Dogs inadequately synthesize citrulline(the precursor of arginine)from glutamine,glutamate,and proline in the small intestine.Although most breeds of dogs have potential for adequately converting cysteine into taurine in the liver,a small proportion(1.3%-2.5%)of the Newfoundland dogs fed commercially available balanced diets exhibit a deficiency of taurine possibly due to gene mutations.Certain breeds of dogs(e.g.,golden retrievers)are more prone to taurine deficiency possibly due to lower hepatic activities of cysteine dioxygenase and cysteine sulfinate decarboxylase.De novo synthesis of arginine and taurine is very limited in cats.Thus,concentrations of both taurine and arginine in feline milk are the greatest among domestic mammals.Compared with dogs,cats have greater endogenous nitrogen losses and higher dietary requirements for many amino acids(e.g.,arginine,taurine,cysteine,and tyrosine),and are less sensitive to amino acid imbalances and antagonisms.Throughout adulthood,cats and dogs may lose 34%and 21%of their lean body mass,respectively.Adequate intakes of high-quality protein(i.e.,32%and 40%animal protein in diets of aging dogs and cats,respectively;dry matter basis)are recommended to alleviate aging-associated reductions in the mass and function of skeletal muscles and bones.Pet-food grade animal-sourced foodstuffs are excellent sources of both proteinogenic amino acids and taurine for cats and dogs,and can help to optimize their growth,development,and health.

关键词： Animal-sourced foodstuffs Cats Dogs Health Metabolism Nutrition

Recent progress in targeting the sialylated glycan-SIGLEC axis in cancer immunotherapy

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Cancer Biology & Medicine 2023年第5期20卷 369-384页

作者： Yingyan Yu Wenjie peng Department of General Surgery of Ruijin Hospital Shanghai Institute of Digestive Surgeryand Shanghai Key Laboratory for Gastric NeoplasmsShanghai Jiao Tong University School of MedicineShanghai 200025China Shanghai Center for Systems Biomedicine Shanghai Jiao Tong UniversityShanghai 200240China

Malignant tumors are complex structures composed of cancer cells and tumor microenvironmental cells.In this complex structure,cells cross-talk and interact,thus jointly promoting cancer development and metastasis.Recently,immunoregulatory molecule-based cancer immunotherapy has greatly improved treatment efficacy for solid cancers,thus enabling some patients to achieve persistent responses or cure.However,owing to the development of drug-resistance and the low response rate,immunotherapy against the available targets PD-1/PD-L1 or CTLA-4 has limited benefits.Although combination therapies have been proposed to enhance the response rate,severe adverse effects are observed.Thus,alternative immune checkpoints must be identified.The SIGLECs are a family of immunoregulatory receptors(known as glyco-immune checkpoints)discovered in recent years.This review systematically describes the molecular characteristics of the SIGLECs,and discusses recent progress in areas including synthetic ligands,monoclonal antibody inhibitors,and Chimeric antigen receptor T(CAR-T)cells,with a focus on available strategies for blocking the sialylated glycan-SIGLEC axis.Targeting glyco-immune checkpoints can expand the scope of immune checkpoints and provide multiple options for new drug development.

关键词： SIGLEC sialylated glycan glyco-immune checkpoint high affinity SIGLEC-ligands anti-SIGLEC antibodies

Effect of Ta on solidification characteristics and mechanical properties of DZ411 Ni-based superalloy

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中国铸造:英文版 2023年第5期20卷 376-386页

作者： Peng Peng Zi-jie Liu Yuan-li Xu Xu-dong Zhang Zhi-kun Ma Jia-tai Wang School of Materials and Energy Lanzhou UniversityLanzhou 730000China School of Materials Science and Engineering Northwestern Polytechnical UniversityXi'an 710072China School of Physics and Electronic Information Qinghai Normal UniversityXining 810008QinghaiChina

The effects of Ta content(2.72wt.%,3.10wt.%and 4.00wt.%)on the solidification characteristics and mechanical properties of directionally solidified DZ411 Ni-based superalloys were investigated.It is found that the content of Mo decreases with the increase of Ta in liquid phase after directional solidification,indicating the addition of Ta can reduce the element segregation in alloys.The primary and secondary dendrite arm spacings(PDAS and SDAS)of the DZ411 alloy increase with the addition of Ta,which are consistent with the models by Hunt and Wagner.The increase of PDAS and SDAS can provide enough space for the growth of tertiary dendrite arms,which hinders the growth of unfavorably oriented primary dendrites.As a result,the addition of Ta facilitates the growth of favorably oriented dendrites.More MC carbides andγ-γ'eutectics are formed in the interdendritic regions,which is attributed to the segregation of Ta in the liquid phase.Furthermore,the degree of supersaturation of W,Mo inγmatrix increases with the increase of Ta,thus,the addition of Ta promotes the formation of TCP phase.The addition of Ta also increases the microhardness in both the primary dendrite and interdendritic regions of the alloy,and the microhardness of the primary dendrite is closer to that in interdendritic regions with the increase of Ta.

关键词： DZ411 superalloy directional solidification Ta dendrite arm spacing microhardness