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Microstructure and Martensitic Transformation Behaviors of Explosively Welded NiTi/NiTi Laminates

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Chinese Journal of Aeronautics 2007年第2期20卷 168-171页

作者： yan Zhu cui li-shan zheng yan-jun Department of Materials Science and Engineering China University of Petroleum Beijing 102249 China

The study is a first attempt to prepare bulk NiTi/NiTi shape memory alloy （SMA） laminates with a macroscopic heterogeneous composition by explosive welding and investigate their microstructures and martensitic transformation behaviors. After explosive weld- ing, a perfect interfacial bonding between the two components and a reversible martensitic transformation are realized in the tandem. Results show achievement of a fine granular structure and the maximum value of microhardness near the welding interface because of the excessive cold plastic deformation and the high impact velocity during the explosive welding. Meanwhile, the effects of aging on the transformation of the welded tandem are investigated by differential scanning calorimeter （DSC） and subject to discussion. The trans- formation temperatures of NiTi/NiTi SMAs increase with the rise of the aging temperature. The experimental results indicate the shape memory properties of NiTi/NiTi SMA fabricated by explosive welding can be improved by optimizing the aging technology.

关键词： NiTi shape memory alloy explosive welding martensitic transformation

Irreversibility and transformation randomness of thermoelastic martensitic transformation in Ni–Ti alloys

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Rare Metals 2015年第12期34卷 833-837页

作者： Tian-Wei liu yan-jun zheng li-shan cui Department of Materials Science and Engineering China University of Petroleum

In this work, the in situ optical observation was carried out in complete and incomplete transformation cycles of Ni–Ti alloys. In complete transformation cycles, initial martensite plates nucleate randomly in austenite. However, in a partial transformation cycle, the existing martensite plates have an influence on guiding the formation of subsequent martensite plates. And the randomness decreases with the decrease in transformation volume involved in the partial cycle. It is suggested that the randomness of transformations contributes to the introduction of defects, and the irreversibility associates with transformation randomness of martensite plates. For instance, a higher randomness in transformations could introduce more defects and more obvious irreversibility. On the other hand, defects generated in thermoelastic martensitic transformation are responsible for the hysteresis of transformations. Therefore, the randomness of transformations also contributes to the transformation hysteresis. These results could help further understanding on some martensitic transformation phenomena of shape memory alloys, such as the nonlinear and history-dependent characteristic.

关键词： Thermoelastic martensitic transformation Shape memory alloys Transformation sequence Hysteresis

Transformation Sequence Rule of Martensite Plates and Temperature Memory Effect in Shape Memory Alloys

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Acta Metallurgica Sinica(English Letters) 2015年第10期28卷 1286-1290页

作者： Tian-Wei liu yan-jun zheng li-shan cui Department of Materials Science and Engineering China University of Petroleum

In thermoelastic martensitic transformation, it is well established that the first martensite plate appearing upon cooling becomes the final one during reverse transformation to austenite upon heating. The results obtained from this work show that the transformation sequence of the martensite appears to be random. Newly formed martensite plates can modify the elastic strain energy level stored in the already existing martensite. Additionally, the elastic strain energy stored in newly formed martensite is not necessarily to be higher than the remaining martensite. The obtained results may assist in understanding phenomena related to partial transformation of shape memory alloys, such as temperature memory effect.

关键词： Phase transformation Shape memory alloys TEM Transformation sequence

The Two-step Reverse Martensitic Transformations of TiNi Shape Memory Alloy Based on Solution-treatment and Aging

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Chinese Journal of Aeronautics 2006年第B12期19卷 198-201页

作者： JIANG Da-qiang cui li-shan zheng yan-jun JIANG Xiao-hua Department of Materials Science and Engineering China University of Petroleum Beijing 102249 China

A TiNi-alloy is solution-treated in a vacuum furnace of 6.7×10^-3 Pa at 1 223 K for 3.6 ks, and then aged at 773 K for 1.8 ks. The differential scanning calorimetry （DSC） measurements show that after the heat-treatment, takes place a two-step reverse Martensitic transformation, from which results the two-stage recovery strain in a prestrained Martensitic TiNi-alloy wire during heating. The Vickers microhardness indentation test in cross-sectional areas of the TiNi-alloy wire indicates the compositional heterogeneity between its surface layers and its inside. The fact that the sizes of the indentation in surface layers smaller than those in the inside bears witness to the existence of slightly harder surface layers. It is believed that these phenomena are related to the compositional fluctuation caused by the evaporation and oxidization of Ti-element during the solution-treatment and heterogeneity formed during the subsequent aging treatment.

关键词： shape memory alloy (SMA) TiNi solution-treatment heterogeneity

AIM Study on the Reaction of CH2SH Radical with Fluorine Atom

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Chinese Journal of Chemical Physics 2008年第2期21卷 123-130页

作者： cui-hong Suna yan-li Zeng ling-peng Meng Shi-jun zheng Institute of Computational Quantum Chemistry Hebei Normal University Shijiazhuan& 050016 China Chemistry and Chemical Engineering College Shijiazhuang University Shijiazhuang 050035 China

The reaction of CH2SH radical with fluorine atom was studied at the levels of B3LYP/6-311G（d,p） and MP2（Full）/6-311G（d,p）. The computational results show that the reaction has three channels and proceeds by the addition of fluorine atoms on carbon or sulfur sites of CH2SH, forming initial intermediates. The calculated results show that the channel, in which fluorine attaches to the carbon atom to form CH2S and HF, is the most likely reaction pathway. Topological analysis of electron density was carried out for the three channels. The change trends of the chemical bonds on the reaction paths were discussed. The energy transition states and the structure transition regions （states） of the three channels were found. The calculated results show that the structure transition regions are broad in unobvious exothermic reactions or unobvious endothermic reactions, and are narrow in obvious exothermic reactions or obvious endothermic reactions.

关键词： Radical reaction Energy transition state Structure transition state Structure transition region Topological analysis of electronic density

Steric hindrance modulation of hexaazatribenzanthraquinone isomers for high-capacity and wide-temperature-range aqueous proton battery

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National Science Review 2024年第4期11卷 271-282页

作者： Mingsheng yang Yuxin Hao Bei Wang yan Wang liping zheng rui li Huige Ma Xinyu Wang Xiaoming Jing Hongwei li Mengxiao li Zhihui Wang Yujie Dai Guangcun shan Mingjun Hu jun Luo jun yang School of Materials Science and Engineering Beihang University Beijing Institute of Nanoenergy &Nanosystems Chinese Academy of Sciences Center on Nanoenergy Research School of Physical Science & TechnologyGuangxi University School of Chemistry and Chemical Engineering Center on Nanoenergy Research Guangxi University School of Instrumentation Science and Opto-electronics Engineering Beihang University ShenSi Lab Shenzhen Institute for Advanced StudyUniversity of Electronic Science and Technology of China

Organic materials with rich active sites are good candidates of high-capacity anodes in aqueous batteries,but commonly low utilization of active sites limits their ***,two isomers,symmetric and asymmetric hexaazatribenzanthraquinone（s-HATBAQ and a-HATBAQ）,with rich active sites have been synthesized in a controllable *** has been revealed for the first time that a sulfuric acid catalyst can facilitate the stereoselective formation of *** to the reduced steric hindrance in favor of proton insertion as well as the amorphous structure conducive to electrochemical dynamics,s-HATBAQ exhibits 1.5 times larger specific capacity than ***,the electrode of s-HATBAQ with50% reduced graphene oxide（s-HATBAQ-50%rGO） delivers a record high specific capacity of405 mAh g-1in ***,the assembled MnO2//s-HATBAQ-50%rGO aqueous proton full batteries show an exceptional cycling stability at 25℃ and can maintain ～92% capacity after1000 cycles at 0.5 A g-1at-80℃.This work demonstrates the controllable synthesis of isomers,showcases a wide-temperature-range prototype proton battery and highlights the significance of precise mole cular structure modulation in organic energy storage.

关键词： stereoisomers steric effect aqueous battery super cycling stability ultra-low temperature proton battery

Prevalence of Kaposi's sarcoma-associated herpesvirus in Uygur and Han populations from the Urumqi and Kashgar regions of Xinjiang, China

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Virologica Sinica 2017年第5期32卷 396-403页

作者： jun zheng yang yang Meng cui Zhan-jun Shu li-li Han Zhen-Qiu liu Charles Wood Tiejun Zhang yan Zeng Key Laboratory of Xinjiang Endemic and Ethnic Disease & Department of Biochemistry School of Medicine Shihezi University Shihezi 832000 China Department of Stomatology The First Affiliated Hospital School of Medicine Shihezi University Shihezi832000 China Division of AIDS Research National Traditional Chinese Medicine Clinical Research Bases in XinjiangUrumqi 830000 China Department of Gynecology Xinjiang Uygur Autonomous Region People's Hospital Urumqi 830001China Department of Epidemiology School of Public Health Fudan University Shanghai 200032 China Nebraska Center of Virology and the School of Biological Sciences Universityof Nebraska-LincolnLincoln 68583 USA

Kaposi's sarcoma-associated herpesvirus(KSHV) is the infectious etiologic agent associated with Kaposi's sarcoma(KS), primary effusion lymphoma, and multicentric Castleman disease. It has been shown that high KSHV prevalence and high incidence of both classic KS and AIDSassociated KS are found mostly among people of Uygur ethnicity in Xinjiang, while people of Han ethnicity in Xinjiang have a higher KSHV seroprevalence than those of other Han populations in China's Mainland. However, it is still unclear why there is such geographical and population variation in KSHV distribution in China. In this work, we focused on the populations in the Kashgar region and Urumqi area, where a total of 1294 research subjects were randomly selected to investigate the potential correlation between KSHV prevalence and different ethnicities in endemic areas of Xinjiang, and to determine risk factors that may affect KSHV infection rates or KS incidence. We identified a high seroprevalence of KSHV and high peripheral blood DNA infection in the general Uygur and Han populations in both Urumqi and Kashgar regions of Xinjiang, and determined that advancing age, low education level, and stationary population status affect KSHV infection rates. Further, KSHV-positive Uygur participants were shown to have higher prevalence of neutralizing antibodies and neutralizing antibody titers than KSHV-positive Han participants.

关键词： Kaposi’s sarcoma associated herpesvirus(KSHV) prevalence Uygur ethnicity Han ethnicity Xinjiang

Frequency-modulated continuous waves controlled by space-time-coding metasurface with nonlinearly periodic phases

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light(Science & Applications) 2022年第10期11卷 2424-2434页

作者： jun Chen Ke jun yan Dai jun Wei Zhang Zhanye Chen Ming zheng Chen Yunfeng Lu Lei Zhang li Wang Qun yan Zhou Long li Jin shan Ding Qiang Cheng Tie jun cui Institute of Electromagnetic Space Southeast University210096 NanjingChina State Key Laboratory of Millimeter Waves Southeast University210096 NanjingChina School of Electronic Engineering Xidian University710071 Xi'anChina

The rapid development of space-time-coding metasurfaces(STCMs)offers a new avenue to manipulate spatial electromagnetic beams,waveforms,and frequency spectra simultaneously with high *** date,most studies are primarily focused on harmonic generations and independent controls of finite-order harmonics and their spatial waves,but the manipulations of continuously temporal waveforms that include much rich frequency spectral components are still limited in both theory and experiment based on ***,we propose a theoretical framework and method to generate frequency-modulated continuous waves(FMCWs)and control their spatial propagation behaviors simultaneously via a novel STCM with nonlinearly periodic *** the carrier frequency of FMCW changes with time rapidly,we can produce customized time-varying reflection phases at will by the required FMCW under the illumination of a monochromatic *** importantly,the propagation directions of the time-varying beams can be controlled by encoding the metasurface with different initial phase gradients.A programmable STCM prototype with a full-phase range is designed and fabricated to realize reprogrammable FMCW functions,and experimental results show good agreement with the theoretical analyses.

关键词： nonlinear continuous periodic

XOR spin logic operated by unipolar current based on field-free spin-orbit torque switching induced by a lateral interface

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Rare Metals 2024年第8期43卷 3868-3875页

作者： yan-Ru li Mei-Yin yang Guo-Qiang Yu Bao-shan cui Jin-Biao liu Yong-liang li Qi-Ming Shao jun Luo Key Laboratory of Microelectronic Devices and Integrated Technology Institute of MicroelectronicsChinese Academy of Sciences(IMECAS)Beijing 100029China University of Chinese Academy of Sciences(UCAS) Beijing 100049China songshan Lake Materials Laboratory Dongguan 523808China Institute of Physics Chinese Academy of SciencesBeijing 100190China Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education Lanzhou UniversityLanzhou 730000China Department of Electronic and Computer Engineering The Hong Kong University of Science and TechnologyHong Kong 999077China

Spin logics have emerged as a promising avenue for the development of logic-in-memory *** particular,the realization of XOR spin logic gates using a single spin-orbit torque device shows great potential for low-power stateful logic circuits in the next *** this study,we successfully obtained the XOR logic gate by utilizing a spin-orbit torque device with a lateral interface,which was created by local ion implantation in the Ta/Pt/Co/Ta Hall device exhibiting perpendicular magnetic *** angle of the lateral interface is set at 45°relative to the current direction,leading to the competition between symmetry breaking and current-driven Néel-type domain wall ***,the field-free magnetic switching reversed is realized by the same sign of current amplitude at this *** on this field-free magnetic switching behavior,we successfully proposed an XOR logic gate that could be implemented using only a single spin-orbit torque Hall *** study provides a potentially viable approach toward efficient spin logics and in-memory computing architectures.

关键词： Filed-free magnetic switching Spin-orbit torque XOR logic gate Lateral interface