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Thermal Stability of WB_2 and W–B–N Films Deposited by Magnetron Sputtering

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Acta Metallurgica Sinica(English Letters) 2019年第1期32卷 136-144页

作者： Yan-Ming liu Tong li Feng liu Zhi-liang Pei College of Materials Science and Engineering Xi'an Shiyou University Institute of Metal Research Chinese Academy of Sciences

The work is mainly to study the thermal stability including the phase stability, microstructure and tribo-mechanical properties of the AlB_2-type WB_2 and W–B–N(5.6 at.% N) films annealed in vacuum at various temperatures, which are deposited on Si and GY8 substrates by magnetron sputtering. For the WB_2 and W–B–N films deposited on Si wafers, as the annealing temperature increases from 700 to 1000 °C, a-WB(700 °C) and Mo_2B_5-type WB_2(1000 °C) are successively observed in the AlB_2-type WB_2 films, which show many cracks at the temperature ≥ 800 °C resulting in the performance failure; by contrast, only slight α-WB is observed at 1000 °C in the W–B–N films due to the stabilization eff ect of a-BN phase, and the hardness increases to 34.1 GPa fi rst due to the improved crystallinity and then decreases to 31.5 GPa ascribed to the formation of α-WB. For the WB_2 and the W–B–N films deposited on wc–Co substrates, both the WB_2 and W–B–N films react with the YG8(wc–Co) substrates leading to the formation of CoWB, CoW_2B_2 and CoW_3B_3 with the annealing temperature increasing to 900 °C; a large number of linear cracks occur on the surface of these two films annealed at ≥ 800 °C leading to the fi lm failure; after vacuum annealing at 700 °C, the friction performance of the W–B–N films is higher than that of the deposited W–B–N films, while the wear resistance of the WB_2 films shows a slight decrease compared with that of the deposited WB_2 films.

关键词： AlB2-type WB2 films W–B–N films Magnetron sputtering Thermal stability Mechanical properties

Methods of early detection:would clinical breast examination and breast ultrasonography be a good alternative to mammography?

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中华乳腺病杂志（电子版） 2011年第6期5卷 1-9页

作者： Adrian YS Yip Louis wc Chow Wings TY Loo Eleanor YY Ong Wincy Chan Organisation for Oncology and Translational Research Hong Kong Clinical Trials Centre Li Ka Shing Faculty of MedicineThe University of Hong KongHong Kong Comprehensive Centre for Breast Diseases UNIMED Medical InstituteHong Kong

Breast cancer is one of the leading causes of cancer deaths among women[1].In the past 40 years,breast cancer incidence has doubled or even tripled in developed countries such as South Korea and Japan; whereas it is a... 详细信息

关键词：摘要编辑部编辑工作读者

Emotions in second language acquisition:A critical review and research agenda

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外语界 2020年第1期 34-49页

作者： DEWAELE Jean-Marc li Chengchen Birkbeck University of LondonLondon WC1B 5DT School of Foreign Languages Huazhong University of Science and TechnologyWuhan 430074

本文从三个方面系统梳理二语学习情绪研究:(1)三个发展阶段及每个阶段的研究范围和热点;(2)主要相关理论及假设;(3)重要研究方法及不足。基于三个方面的回顾总结,文章对未来二语学习情绪研究、二语教学进行了展望,并提出相应建议。

关键词：二语学习情绪积极心理学二语习得外语愉悦外语焦虑

Research gaps for three main tropical diseases in the People’s Republic of China

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Infectious Diseases of Poverty 2013年第1期2卷 112-125页

作者： Qi Zheng Samantha Vanderslott Bin Jiang li-li Xu Cong-Shan liu Le-Le Huo li-Ping Duan Ning-Bo Wu Shi-Zhu li Zhi-Gui Xia Wei-Ping Wu Wei Hu Hao-Bing Zhang National Institute of Parasitic Disease Chinese Center for Disease Control and PreventionWHO Collaborating Centre on MalariaSchisostomiasis and FilariasisKey Laboratory of Parasite and Vector BiologyMinistry of Health207 Rui Jin Er RdShanghai 200025People’s Republic of China The Department of Science and Technology Studies University College LondonLondon WC1E 6BTUK

This scoping review analyzes the research gaps of three diseases:schistosomiasis japonica,malaria and *** on available data in the ***,we highlight the gaps between control capacity and prevalence levels,and between diagnostic/drug development and population need for treatment at different stages of the national control *** reviewing the literature from 848 original studies and consultations with experts in the field,the gaps were identified as ***,the malaria research gaps include(i)deficiency of active testing in the public community and no appropriate technique to evaluate elimination,(ii)lack of sensitive diagnostic tools for asymptomatic patients,(iii)lack of safe drugs for mass ***,gaps in research of schistosomiasis include(i)incongruent policy in the implementation of integrated control strategy for schistosomiasis,(ii)lack of effective tools for Oncomelania *** control,(iii)lack of a more sensitive and cheaper diagnostic test for large population samples,(iv)lack of new drugs in addition to ***,gaps in research of echinococcosis include(i)low capacity in field epidemiology studies,(ii)lack of sanitation improvement studies in epidemic areas,(iii)lack of a sensitivity test for early diagnosis,(iv)lack of more effective drugs for short-term *** believe these three diseases can eventually be eliminated in China's Mainland if all the research gaps are abridged in a short period of time.

关键词： Schistosomiasis Malaria Echinococcosis Epidemiology Diagnosis Chemotherapy Research capacity building

Cross-sectional survey following a longitudinal study on mental health and insomnia of people with sporadic COVID-19

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World Journal of Psychiatry 2022年第8期12卷 1076-1087页

作者： Xiao-Jun li Tian-Ze Guo Yan Xie Yan-Ping Bao Jia-Yue Si Zhe li Yi-Ting Xiong Hui li Su-Xia li lin Lu Xue-Qin Wang Department of Psychiatry Peking University International HospitalBeijing 102206China Department of Bioengineering University of California San DiegoSan DiegoCA 92093United States Department of Psychology Peking University International HospitalBeijing 102206China Department of Epidemiology National Institute on Drug Dependence and Beijing Key laboratory of Drug DependencePeking UniversityBeijing 100191China University of California Davis DavisCA 95616United States Department of History University College LondonLondon WC1E 6BTUnited Kingdom Department of Psychiatry Peking University Sixth HospitalPeking University Institute of Mental HealthNHC Key Laboratory of Mental Health(Peking University)National Clinical Research Center for Mental Disorders(Peking University Sixth Hospital)Peking UniversityBeijing 100191China Department of Clinical Pharmacology National Institute on Drug Dependence and Beijing Key Laboratory of Drug DependencePeking UniversityBeijing 100191China Peking-Tsinghua Centre for life Sciences and Peking University-International Development Group/McGovern Institute for Brain Research Peking UniversityBeijing 100091China

BACKGROUNDIn the post-pandemic era, the emergence of sporadic cases of coronavirus disease 2019 (COVID-19) and the scale of the pandemic are unpredictable. Therefore, the impact ofsporadic cases of COVID-19 and isolation measures on mental health and sleep in different groupsof people need to be *** clarify the severity of psychological problems and insomnia of staff and community residentsaround a hospital with sporadic cases of COVID-19, and their relationship with quarantinelocation and long-term *** cross-sectional survey was conducted on community residents and medical staff. Many of thesemedical staff had been subjected to different places of quarantine. Community residents did notexperience quarantine. Hospital anxiety and depression scale (HADS), acute stress disorder scale(ASDS) and insomnia severity index (ISI) were used to evaluate anxiety and depression, acutestress disorder symptoms, and the severity of insomnia. Additionally, we conducted a 1-yearfollow-up study on medical staff, with related scales measurement immediately after and one yearafter the 2-wk quarantine *** included 406 medical staff and 226 community residents. The total scores of ISI and subscale inHADS of community residents were significantly higher than that of medical staff. Furtheranalysis of medical staff who experienced quarantine showed that 134 were quarantined in hotels,70 in hospitals and 48 at home. Among all subjects, the proportions of HADS, ASDS and ISI scoresabove normal cutoff value were 51.94%, 19.17% and 31.11%, respectively. Multivariable logisticregression analysis found that subjects with higher total ASDS scores had a greater risk to developanxiety and depression. The total ISI score for medical staff in hotel quarantine was significantlyhigher than those in home quarantine. Total 199 doctors and nurses who completed the 1-yearfollow-up study. Compared with baseline, HADS and ASDS scores decreased significantly oneyear after the

关键词： COVID-19 Depression Anxiety Insomnia Quarantine

Unveiling the critical role of TiO_(2)-supported atomically dispersed Cu species for enhanced photofixation of N_(2)to nitrate

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Fundamental Research 2024年第4期4卷 934-940页

作者： Dong li Yunxuan Zhao Chao Zhou li-Ping Zhang Junwang Tang Tierui Zhang Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and ChemistryChinese Academy of SciencesBejing 100190China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBejing 100049China School of Future Technology University of Chinese Academy of SciencesBejing 100049China Department of Chemical Engineering University College LondonLondon WC1E7JEUnited Kingdom

Nitrate products are widely used in manufacturing as crucial raw materials and *** traditional nitrate synthesis process involves high energy consumption and emission,thereby opposing the goals of zero-carbon emission and green ***,a sustainable roadmap for nitrate synthesis that uses green energy input,clean N sources,and direct catalytic processes is urgently required(e.g.,developing a novel photosynthesis system).Here,we synthesized TiO2-supported atomically dispersed Cu species for N_(2)photofixation to nitrate in a flow *** optimized photocatalyst yielded a high nitrate photosynthesis rate of 0.93μmol h-1 and selectivity of~90%,which is superior to most of the values reported thus ***,experimental results and in-situ investigations revealed that the atomically dispersed Cu sites in the as-designed sample significantly enhanced the separation and transfer efficiency of photogenerated carriers,adsorption and activation of reactants,and the formation of chemisorbed O_(x)intermediates,thereby realizing the excellent photofixation of N_(2)to nitrate.

关键词： N_(2) photofixation TiO_(2) Nitrate photosynthesis Cu species NO_(x),intermediates

Synthesis of growth-type polycrystalline diamond compact (PDC) using the solvent Fe_(55)Ni_(29)Co_(16) alloy under HPHT

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Science China(Physics,Mechanics & Astronomy) 2012年第8期55卷 1394-1398页

作者： JIA HongSheng JIA XiaoPeng MA HongAn li HaiBo Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education Jilin Normal University Siping 136000 China State Key Laboratory of Superhard Materials Jilin University Changchun 130012 China

A growth-type polycrystalline diamond compact （PDC） was synthesized under high temperature and high pressure （HPHT）. The infiltration technique was used with an Fe55Ni29Co16 （KOV） alloy as the sintering solvent. The morphology and weight ra- tio of the PDC were investigated through scanning electron microscopy （SEM） and electron dispersion spectroscopy （EDS）. Note that the KOV alloy evenly infiltrated throughout the polycrystalline diamond （PCD） layer and wc-Co substrate in a short sintering time due to its low viscosity and high soakage capability. A transition layer confirmed the presence of the M^C phase near the interface of the PDC, which can make the diamond layer and wc-Co substrate combine as a complex material. X-ray diffraction （XRD） performed on the PCD layer confirmed the presence of cubic diamond, wc, cubic CoCx, the high tempera- ture cubic phase of c^-Co, the alloy phase of FeNix, and no graphite phase. Besides, a surface residual stress of the PCD layer, measured with reasonable accuracy using micro-Raman spectroscopy, is found to be a homogeneous compressive stress with an average value of 0.16 GPa, much lower than that of the powders-mixing method.

关键词： HPHT infiltration PDC Fe55Ni29Co16 alloy residual stress

Quantum phase for an electric quadrupole moment in noncommutative quantum mechanics

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Frontiers of physics 2014年第4期9卷 446-450页

作者： Halqem Nizamidin Abduwali Anwar Sayipjamal Dulat Kang li School of Mathematical Science Capital Normal University Beijing 100048 China School of Physics Science and Technology Xinjiang University Urumqi 830046 China Department of Physics Hangzhou Normal University Hangzhou 310036 China

We study the noncoInmutative nonrelativistic quantum dynamics of a neutral particle, which possesses an electric qaudrupole moment, in the presence of an external magnetic field. First, by intro ducing a shift for the magnetic field, we give the Schrodinger equations in the presence of an external magnetic field both on a noncommutative space and a noncomlnutative phase space, respectively. Then by solving the SchrSdinger equations both on a noneommutative space and a noncommutative phase space, we obtain quantum phases of the electric quadrupole moment, respectively. wc demonstrate that these phases are geometric and dispersive.

关键词： noncommutative quantum mechanics electric quadrupole moment quantum phase,nonconnnutative phase space

Impacts of dams and land-use changes on hydromorphology of braided channels in the Lhasa River of the Qinghai-Tibet Plateau,China

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International Journal of Sediment Research 2022年第2期37卷 214-228页

作者： Yuchi You Zhiwei li Peng Gao Tiesong Hu School of Hydraulic Engineering Changsha University of Science & Technology State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Department of Geography and the Environment Syracuse University

Among braided rivers developed on the Qinghai-Tibet Plateau of China at very high elevations(>3,500 m),the middle and lower reaches of the Lhasa River have been affected by comprehensive human activities mainly involving dam construction,urbanization,farming,afforestation,and *** the current study,the impacts of these human activities on hydrology and morphology of the four braided reaches downstream of a cascaded of two dams are *** study period was divided into 1985-2006(P1),2006-2013(P2),and 2013-2019(P3),representing the natural and changed flow regimes by *** available daily discharge data at two stations within the four braided reaches,dam-induced hydrological alteration was analyzed based on the indicators of hydrologic alteration and range of variability approach and key discharge proxies were *** sensed images also were selected in the three periods and morphological metrics extracted from them were compared for the four reaches among these *** hydrological regimes were found for only two *** total channel width(wc) and braiding intensity(BIt) followed different temporal trends among the four *** average shift rates of the main channel in the four reaches were higher in the short(P2-P3) than in the long(P1-P2 and P1-P3) *** longitudinal changes of wcand the number of channels did not have any identifiable trend among the four *** linking the morphological changes to quantified spatial and temporal patterns of various human activities,it was found that(1) the two dams had insignificant impact on channel morphology,suggesting that the studied braided river might have a short relaxation time and(2) the evolutional trajectories of morphological changes in most of the four reaches were similar,suggesting that temporal trends of morphological changes due to complex human activities are not affected by the different physiographic settings of the *** exploitati

关键词： Braided river Channel morphology Human activities Dam impact