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P掺杂β-FeSi_(2)材料的制备与热电输运性能

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无机材料学报 2024年第8期39卷 895-902,I0003页

作者：程俊张家伟仇鹏飞陈立东史迅中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室上海200050 中国科学院大学材料科学与光电技术学院北京100049 中国科学院大学杭州高等研究院化学与材料科学学院杭州310024

β-FeSi_(2)作为一种绿色环保、高温抗氧化的热电材料,在工业余热回收领域具有潜在的应用价值。虽然磷(P)是一种理想的β-FeSi_(2)硅(Si)位的n型掺杂元素,但是P掺杂β-FeSi_(2)易出现第二相,从而限制了其热电性能的提升。本研究采用感... 详细信息

β-FeSi_(2)作为一种绿色环保、高温抗氧化的热电材料,在工业余热回收领域具有潜在的应用价值。虽然磷(P)是一种理想的β-FeSi_(2)硅(Si)位的n型掺杂元素,但是P掺杂β-FeSi_(2)易出现第二相,从而限制了其热电性能的提升。本研究采用感应熔炼法合成了一系列FeSi_(2)-xPx(x=0,0.02,0.04,0.06)样品,极大程度地避免了第二相的产生,并系统研究了P掺杂对β-FeSi_(2)热电输运性能的影响。结果表明,P在β-FeSi_(2)中的掺杂极限约为0.04,与前期的理论缺陷计算结果相符。此外,P掺杂优化了β-FeSi_(2)的热电性能,在850 K时,FeSi1.96P0.04的最高热电优值ZT约为0.12,远高于已有的研究结果(673 K,最高ZT仅为0.03)。然而,与同为n型Co和Ir掺杂的β-FeSi_(2)相比(其载流子浓度可达10^(22)cm^(-3)),P掺杂β-FeSi_(2)的载流子浓度较低,最高仅为10^(20)cm^(-3),这导致其电声散射效应较弱,从而限制了整体热电性能的提升。若能提高其载流子浓度,则热电性能有望得到进一步提升。

关键词： β-FeSi_(2) 热电材料 P掺杂感应熔炼载流子浓度电声散射

Inconsistent radiotherapy effects between primary tumors and axillarylymphnodes

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Cancer Biology & Medicine 2022年第12期19卷 1617-1621页

作者： Zhao Bi pengfei qiu Zhaopeng Zhang Yongsheng Wang Breast Cancer Center Shandong Cancer Hospital and InstituteShandong First Medical University and Shandong Academy ofMedical SciencesJinan250000China

Negative surgical margins are important for patients treated with breast-conserving therapy(BCT)BCT has been a standard practice in breast cancer treatment for more than 2 *** patients who receive BCT,a positive surgical margin is defined by the presence of ink at the surfaces of surgical specimens,in either the invasive tumor cells or breast ductal carcinoma in sit,thus implying potentially incomplete resection,which is associated with a significantly elevated risk of ipsilateral breast tumor recurrence(IBTR)1,2.A meta-analysis with a median follow-up of 6.6 years has reported an odds ratio(OR)of 1.96[95%confidence interval(CI):1.72-2.24]for IBTR in patients with positive rather than negative surgical margins(no ink on the tumors).

关键词： breast tumors elevated

Analysis of Dynamics and Driving Factors of Wetland Landscape in Zoige,Eastern Qinghai-Tibetan Plateau

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Journal of Mountain Science 2009年第1期6卷 42-55页

作者： qiu pengfei WU Ning LUO Peng WANG Zuyuan LI Maihe Chengdu Institute of Biology Chinese Academy of Sciences Chengdu 610041 China Sichuan Instute of Territorial Survey and Plan Chengdu 610031 China Swiss Federal Research Institute WSL Zuercherstrasse 111 CH-89o3 Birmensdorf Switzerland Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China

Zoige Wetland is one of the largest plateau wetlands in the world. This paper provides a dynamic analysis of spatial and temporal patterns of the wetland in Zoige, Eastern Qinghai-Tibetan Plateau, supported by ERDAS8.7 and ArcGIS9.0. It is the first comparative analysis of a system of rapidly changing wetland with landscape patterns in Zoige, using 3 classified landsat Thematic Mapper images of 1977, 1994 and 2001. The classified images were used to generate wetland distributing maps, and shape index （S）, diversity index （H）, dominance index （D）, evenness index （E）, fragmentation index （F） and fractal dimension （Fd） were calculated and analyzed spatiotemporally across pure grazing area in Zoige for each landscape type and in different periods （before 1977, during 1977-1994 and 1994-2001）, as well as the driving forces of natural and anthropogenic. The study shows that for a comprehensive understanding of the shapes and trajectories of the shrinking and desertificated land expansion of the wetland, a spatiotemporal landscape metrics analysis in different periods is an improvement than only with landscape changing rates. This type of analysis can also be used to infer underlying social, economic, and political processes that drive the observed wetland forms. The results indicate that wetland patterns can be changed over relatively short periods of time. The total area of lake reduced by 164.86 km^2, grassland extended by 141.74 km^2, semi-marsh extended by 105.94 km^2, marsh reduced by 86.00 km^2 the number of landscape patches reduced by 56, and their average area decreased by 2.68 km^2, the successions within lake, marsh, semi-marsh and grassland were found obviously. S decreased stepwise： D and F increased but H decreased： The changing rate after 1994 was 2.3 to 2.9 times greater than that before. The change of the wetland landscape patterns resulted in the interaction between socio-ceenomic and natural forces of positive and negative aspects; and natural factors

关键词： Landscape pattern driving force fragmentation marsh pasture metrics Zoige Qinghai-Tibetan Plateau

Microstructure and mechanical properties stability of pre-hardening treatment in Al-Cu alloys for pre-hardening forming process

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 539-551页

作者： Liping Tang pengfei Wei Zhili Hu qiu Pang Hubei Longzhong laboratory Xiangyang 441000China Hubei Key Laboratory of Advanced Technology for Automotive Components School of Automotive EngineeringWuhan University of TechnologyWuhan 430070China Hubei Engineering Research Center for Green&Precision Material Forming Wuhan University of TechnologyWuhan 430070China Key Laboratory of Metallurgical Equipment and Control Technology of Ministry of Education School of Machinery and AutomationWuhan University of Science and TechnologyWuhan 430081China

The stability of the microstructure and mechanical properties of the pre-hardened sheets during the pre-hardening forming(PHF)process directly determines the quality of the formed *** microstructure stability of the pre-hardened sheets was in-vestigated by differential scanning calorimetry(DSC),transmission electron microscopy(TEM),and small angle X-ray scattering(SAXS),while the mechanical properties and formability were analyzed through uniaxial tensile tests and formability *** results in-dicate that the mechanical properties of the pre-hardened alloys exhibited negligible changes after experiencing 1-month natural aging(NA).The deviations of ultimate tensile strength(UTS),yield strength(YS),and sheet formability(Erichsen value)are all less than 2%.Also,after different NA time(from 48 h to 1 month)is applied to alloys before pre-hardening treatment,the pre-hardened alloys possess stable microstructure and mechanical properties as ***,with the extension of NA time before pre-hardening treatment from 48 h to 1 month,the contribution of NA to the pre-hardening treatment is *** a yield strength increment of 20 MPa is achieved,with no loss in *** limited enhancement is mainly attributed to the fact that only a limited number of clusters are transformed into Guinier-Preston(GP)zones at the early stage of pre-hardening treatment,and the formation ofθ''phase inhibits the nucleation and growth of GP zones as the precipitated phase evolves.

关键词： Al-Cu alloy pre-hardened alloy natural aging mechanical properties microstructure

Na-doping-induced modification of the Cu_(2)ZnSn(S,Se)_(4)/CdS heterojunction towards efficient solar cells

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Journal of Energy Chemistry 2021年第6期30卷 618-626,I0015页

作者： Yali Sun Hongling Guo pengfei qiu Shengli Zhang Siyu Wang Li Wu Jianping Ao Yi Zhang Institute of Photoelectronic Thin Film Devices and Technology and Tianjin Key Laboratory of Thin Film Devices and Technology Nankai UniversityTianjin 300350China College of Physics Science and Technology Hebei UniversityBaoding 071002HebeiChina The MOE Key Laboratory of Weak-Light Nonlinear Photonics School of PhysicsNankai UniversityTianjin 300071China

It is very important to understand why a small amount of alkali metal doping in Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)solar cells can improve the conversion *** this work,Na-doped CZTSSe is prepared by a simple solution method,and then the effects on the surface properties of the absorber layer,the buffer layer growth,and the modifications of the solar cell performance induced by the Na doping are *** surface of the absorber layer is more Cu-depletion and less roughness due to the Na *** addition,the contact angle of the surface increases because of Na *** a consequence,the thickness of the CdS buffer layer is significantly reduced and the optical losses in the CdS buffer layer are *** difference of quasi-Fermi levels(EFn-EFp) increases with a small amount of Na doping in the CZTSSe solar cell,so that open circuit voltage(VOC) increased *** work offers new insights into the effects of Na doping on CZTSSe via a solution-based approach and provides a deeper understanding of the origin of the efficiency improvement of Na-doped CZTSSe thin film solar cells.

关键词： Cu_(2)ZnSn(S,Se)_(4)solar cells Na doping Heterojunction Contact angles Simulation analysis

Optimization of regional nodal irradiation in the era of sentinel lymph node biopsy

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Cancer Biology & Medicine 2023年第2期20卷 89-92页

作者： Zhao Bi Xue’er Wang pengfei qiu Peng Chen Yongsheng Wang Shandong Cancer Hospital and Institute Shandong First Medical University and Shandong Academy of Medical SciencesJinan 250017China Tianjin Medical University Cancer Institute&Hospital National Clinical Research Center for CancerKey Laboratory of Cancer Prevention and TherapyTianjinTianjin's Clinical Research Center for CancerTianjin 300060China

Historically,axillary lymph node dissection(ALND)was the standard management for axillary sentinel lymph node(SLN)-positive patients,because it enables full assessment of overall axillary lymph node(ALN)metastasis sta... 详细信息

关键词： lymph metastasis dissection

Suppressing the donor-like effect via fast extrusion engineering for high thermoelectric performance of polycrystalline Bi_(2)Te_(2.79)Se_(0.21)

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Journal of Materiomics 2023年第2期9卷 345-352页

作者： Xusheng Liu Tong Xing pengfei qiu Tingting Deng Peng Li Xuewen Li Xiaoya Li Xun Shi State Key Lab of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai200050China Key Lab for Light-weight Materials Nanjing Tech UniversityNanjing211816China

Bi2Te3-based alloys are the most mature commercial thermoelectric(TE)materials for the cooling application near room ***,the poor mechanical properties of the commercial zone melting(ZM)ingot severely limits the further ***,due to the donor-like effect,the robust polycrystalline n-type bulks usually have low TE performance near room ***,based on the commercial ZM ingots,a high figure of merit(zT)of 1.0 at 320 K and good mechanical properties are achieved via the hot *** dynamic recrystallization in the hot-extrusion process can suppress the donor-like effect and refine the large ZM grains into fine-equiaxed ***,the obtained polycrystalline Bi2Te2.79Se0.21 has good preferential orientation and high carrier mobility(m).The high m and the weaken donor-like effect maintain the high power factor(PF)of 43.1 mW cm^(-1)K^(-2)in the hot-extruded ZM *** to the enhanced phonon scattering,the total thermal conductivity ktot decreased to 1.35 W·m^(-1)·K^(-1).To demonstrate the good mechanical properties of the extruded ZM sample,micro TE dices with the cross sections of 300μm×300 mm and 200μm×200 mm are successfully cut from the extrusion *** study provided a fast and low-cost extrusion technique to improve the TE and mechanical properties of the commercial ZM ingot at room temperature.

关键词： Thermoelectric Bismuth telluride Donor-like effect Hot extrusion

Crystalline Structure-Dependent Mechanical and Thermoelectric Performance in Ag_(2)Se_(1‐x)S_(x)System

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Research 2020年第1期2020卷 1089-1098页

作者： Jiasheng Liang pengfei qiu Yuan Zhu Hui Huang Zhiqiang Gao Zhen Zhang Xun Shi Lidong Chen State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Division of Solid-State Electronics Department of Electrical EngineeringUppsala UniversityUppsalaSweden School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China

Self-powered wearable electronics require thermoelectric materials simultaneously with a high dimensionless figure of merit(zT)and good flexibility to convert the heat discharged by the human body into ***_(2)(S,Se)-based semiconducting materials can well satisfy these requirements,and thus,they are attracting great attention in thermoelectric society ***_(2)(S,Se)crystalizes in an orthorhombic structure or monoclinic structure,depending on the detailed S/Se atomic ratio,but the relationship between its crystalline structure and mechanical/thermoelectric performance is still unclear to *** this study,a series of Ag_(2)Se_(1-x)S_(x)(x=0,0.1,0.2,0.3,0.4,and 0.45)samples were prepared and their mechanical and thermoelectric performance dependence on the crystalline structure was systematically investigated.x=0:3 in the Ag_(2)Se_(1-x)S_(x)system was found to be the transition boundary between orthorhombic and monoclinic *** property measurement shows that the orthorhombic Ag_(2)Se_(1-x)S_(x)samples are brittle while the monoclinic Ag_(2)Se_(1-x)S_(x)samples are ductile and *** addition,the orthorhombic Ag_(2)Se_(1-x)S_(x)samples show better electrical transport performance and higher zT than the monoclinic samples under a comparable carrier concentration,most likely due to their weaker electron-phonon *** study sheds light on the further development of flexible inorganic TE materials.

关键词： ductile crystalline attracting

Enhanced Thermoelectric Properties of Cu_(x)Se(1.75 ≤ x ≤ 2.10) during Phase Transitions

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Chinese Physics Letters 2021年第11期38卷 59-66页

作者： Zhongmou Yue Kunpeng Zhao Hongyi Chen pengfei qiu Lidong Chen Xun Shi State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China College of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China

Coupling of a phase transition to electron and phonon transports provides extra degree of freedom to improve the thermoelectric performance, while the pertinent experimental and theoretical studies are still rare. Particularly,the impaction of chemical compositions and phase transition characters on the abnormal thermoelectric properties across phase transitions are largely unclear. Herein, by varying the Cu content x from 1.75 to 2.10, we systemically investigate the crystal structural evolution, phase transition features, and especially the thermoelectric properties during the phase transition for Cu_(x)Se. It is found that the addition of over-stoichiometry Cu in Cu_(x)Se could alter the phase transition characters and suppress the formation of Cu vacancies. The critical scatterings of phonons and electrons during phase transitions strongly enhance the Seebeck coefficient and diminish the thermal conductivity, leading to an ultrahigh dimensionless thermoelectric figure of merit of ~1.38 at 397 K in Cu_(2.10)*** the decreasing Cu content, the critical electron and phonon scattering behaviors are mitigated, and the corresponding thermoelectric performances are reduced. This work offers inspirations for understanding and tuning the thermoelectric transport properties during phase transitions.

关键词： red during Phase Transitions Enhanced Thermoelectric Properties of Cu_(x)Se