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    尊龙凯时 - 人生就是搏!2019年開放課題結題報告


    1Magnetic Reactive Oxygen Species Nanoreactor for Switchable Magnetic Resonance Imaging Guided Cancer Therapy based on pH-sensitive Fe5C2@Fe3O4 Nanoparticles

    Jing Yu(余靚), Fan Zhao, Weiliang Gao, Xue Yang, Yanmin Ju, Lingyun Zhao, Weisheng Guo, Jun Xie, Xing-jie Liang, Xinyong Tao, Juan Li, Yao Ying, Wangchang Li, Jingwu Zheng, Liang Qiao, Subin Xiong, Xiaozhou Mou, Shenglei Che, and Yanglong Hou

    Zhejiang University of Technology, Zhejiang Provincial People’s Hospital, Peking University, Tsinghua University, National Center for Nanoscience and Technology, Jiangsu Normal University

    By taking advantage of the intrinsic acidity and overproduction of H2O2 in the tumor environment, an ROS nanoreactor based on core-shell-structured iron carbide (Fe5C2@Fe3O4) nanoparticles (NPs) was developed through the catalysis of the Fenton reaction. These NPs are able to release ferrous ions in acidic environments to disproportionate H2O2 into •OH radicals, which effectively inhibits the proliferation of tumor cells both in vitro and in vivo. The high magnetization of Fe5C2@Fe3O4 NPs is favorable for both magnetic targeting and T2-weighted magnetic resonance imaging (MRI). Ionization of these NPs simultaneously decreases the T2 signal and enhances the T1 signal in MRI, and this T2/T1 switching process provides the visualization of ferrous ions release and ROS generation for the supervision of tumor curing. These Fe5C2@Fe3O4 NPs show great potential in endogenous environment-excited cancer therapy with high efficiency and tumor specificity and can be guided further by MRI.





    採用電子束蒸發的傾斜生長技術 ,在PS微球陣列上實現了具有高SERS活性 、樹枝狀Ag納米結構周期陣列的製備 。建立了肼的快速 、痕量的檢測方法 ,揭示了Ag納米結構 、局域電磁場和SERS活性之間的關係 。研究成果可指導高性能SERS基底的設計與構築 ,實現對局域電磁場強度和分佈的調控 ,對局域表面等離子激元和SERS檢測領域的研究具有指導意義 。





    隨着特徵尺寸不斷縮小 ,由於晶粒邊界散射和表面散射 ,導致互連線電阻快速上升 。為了緩解這一問題 ,Co在金屬化方案中作為CuW的替代材料具有很高的潛力 。本研究採用Co作為局部接觸孔互連材料 ,採用Co-Ti作為單層阻擋層/襯墊層來代替傳統的厚TiN/Ti雙層結構 ,為互聯線保留更多有效體積 ,從而降低總的互聯電阻 。製備了含Co-Ti和不含Co-Ti的樣品 ,研究了Co-Ti的阻擋特性 。同時 ,在接觸孔中對Co/Co-TiSi的反應機理進行了較全面的研究 。為了進一步評價Co-Ti作為阻擋層的本徵可靠性 ,在500 ℃下對樣品進行了1分鐘 、30分鐘和60分鐘的退火處理 ,使用透射電鏡(TEM)結合相應的電子能量損失譜(EELS) ,分析了不同溫度時間退火後樣品的界面形貌以及元素分佈 。





    350C時 ,Unfaulting現象幾乎沒有出現;而在400C450C ,Unfaulting現象都十分明顯 。在450C有大量直徑為12-20nmPerfect loop生成 ,但也有不少更大尺寸的Frank loop沒有發生Unfaulting演化 。這說明Unfaulting過程中所謂的臨界演變尺寸並不存在 ,也說明Frank loop的堆垛層錯能不是Unfaulting的決定性因素 。


    5Anomalous lattice reconstruction during fracture of 2D ReS


    香港理工大學 應用物理學系

    The monolayer 2D ReS2 membrane experienced anomalous phase transition and lattice reconstruction (scheme shown in left panel) under the strain concentrated zone in the crack tips, as observed by high resolution atomic scale scanning transition electron microscopy imaging (right panel). The tetragonal phases in 2D materials such as transition metal dichalcogenides (TMD) can have different fracture mechanisms from the bulk counterparts.





    所製備的不同功能化多壁碳納米管能夠和多種成骨活性多肽共價結合 ,並能保持成骨多肽的活性 ,從而促進成骨關聯細胞粘附 、增殖以及向成骨質方向分化 。



    尹放 ,徐健 ,周宇倩 ,劉劍波

    尊龙凯时 - 人生就是搏! ,清華大學材料學院

    (a) :在富Ag(貧Br)的生長條件下 ,Cs2AgInBr6具有良好n型導電性質 。圖(b) :通過Bi元素和In元素的合金化形成有序基態結構 ,可以將帶隙降低至1.81eV ,而且帶隙特徵成功調整為直接帶隙 ,這有利於應用於光伏領域 。


    8Physical metallurgy-guided machine learning and artificial intelligent design of ultrahigh-strength steel

    Chi Zhang, Chenchong Wang, Chunguang Shen, Wei Xu

    1. Key Laboratory of Advanced Materials of Ministry of Education, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China

    2.State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang, Liaoning, 110819, China

    In order to make reasonable design for the improvement of comprehensive mechanical properties of ultrahigh-strength steels, the design system with both machine learning and high-throughput optimization algorithm was established. As the basis of the design system, a dataset of ultrahigh-strength steels was compiled from previous literatures. Then, feature engineering guided machine learning model were trained by the dataset and NSGA II algorithm were used for the selection of the optimal solutions from the large-scale solution set with composition features and treatment processing features. The selected optimal solutions by this design system showed prospective mechanical properties, which was also consistent with the physical metallurgy theory. This efficiency design mode could give the enlightenment for the design of other metal structural materials with the requirement of multi-properties


    9Hardening through an Ultrafine Carbide Precipitation in Austenite of a Low-Carbon Steel Containing Titanium and Tungsten

    Zhenqiang Wang

    Harbin Engineering University

    A significant hardening effect was obtained in a low carbon steel containing Ti and W by performing a 20% hot compressive deformation and 60s stress-relaxation at 1148-1198K (875-925oC) in the austenite region. TEM observation indicated that the hardening effect in martensite and bainite was closely associated with a fine dispersion of ultrafine precipitates with particle size of 1-10 nm at peak hardness. These ultrafine precipitates were identified as W, Fe-rich (WFeTi)C carbides with MC-type B1 structure, the crystal parameter of which is quite similar to austenite matrix. Excluding other strengthening factors, the yield strength increment from precipitation hardening of carbides was estimated to be about 33-179MPa at the studied temperature of 1198K (925oC).



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