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

Jing Yu(余靓), 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.










随着特征尺寸不断缩小,由于晶粒边界散射和表面散射,导致互连线电阻快速上升。为了缓解这一问题,Co在金属化方案中作为CuW的替代材料具有很高的潜力。本研究采用Co作为局部接触孔互连材料,采用Co-Ti作为单层阻挡层/衬垫层来代替传统的厚TiN/Ti双层结构,为互联线保留更多有效体积,从而降低总的互联电阻。制备了含Co-Ti和不含Co-Ti的样品,研究了Co-Ti的阻挡特性。同时,在接触孔中对Co/Co-TiSi的反应机理进行了较全面的研究。为了进一步评价Co-Ti作为阻挡层的本征可靠性,在500 ℃下对样品进行了1分钟、30分钟和60分钟的退火处理,使用透射电镜(TEM)结合相应的电子能量损失谱(EELS),分析了不同温度时间退火后样品的界面形貌以及元素分布。





350C时,Unfaulting现象几乎没有出现;而在400C450CUnfaulting现象都十分明显。在450C有大量直径为12-20nmPerfect loop生成,但也有不少更大尺寸的Frank loop没有发生Unfaulting演化。这说明Unfaulting过程中所谓的临界演变尺寸并不存在,也说明Frank loop的堆垛层错能不是Unfaulting的决定性因素。


5Anomalous lattice reconstruction during fracture of 2D ReS


香港理工大学 应用物理学系

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.












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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