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Experimental investigation of spectral evolution in flash radiation by hypervelocity impact on aluminum plates

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Defence Technology（防务技术） 2024年第7期37卷 96-110页

作者： Xing Chen Yonggang Lu zhiwen li Zhonghua Cui Institute of Systems Engineering China Academy of Engineering PhysicsMianyang 621900SichuanChina Chongqing Qianwei Technology Group Co. LtdChongqing 401121China

In this study,a series of hypervelocity impact tests were carried out based on a two-stage light gas gun,and the sequence spectrum and radiation evolution data of the impact products under different impact conditions were *** diameter of the projectile is 3-5 mm,the impact velocity is 3.13-6.58 km/s,and the chamber pressure is 0.56-990 *** spectrum of ejected debris cloud in the 250-310 nm band were obtained using a transient spectral measurement system and a multi-channel radiometer measurement *** test results reveal that the flash radiation intensity increases as a power function with the kinetic energy of the ***,the peak value of the line spectrum decreases as the chamber vacuum degree increases,while the radiation width gradually *** line spectrum in the spectral characterization curve corresponds to the ejected debris clouds splitting phase,which does not produce significant line spectrum during material fragmentation and is dominated by the continuum spectrum produced by blackbody *** will appear one or three characteristic peaks in the flash radiation time curve,the first and second peaks correspond to the penetration phase and the third peak corresponds to the expansion phase of the ejected debris clouds on the time scale,the first and second peaks are more sensitive to the chamber vacuum degree,and when the pressure is higher than 99 Pa,the first and second characteristic peaks will *** radiant heat attenuation of the flash under different impact conditions is significantly different,the attenuation exponent has a power function relationship with the impact velocity and the chamber vacuum degree,while the attenuation exponent has a linear relationship with the diameter of the projectile,the specific expression of the attenuation exponent is obtained by *** findings from this research can serve as a valuable reference for remote diagnostic technologies based on flash radiation characte

关键词： Hypervelocity impact Flash radiation Evolution Spectral characteristics Damage evaluation

Highly Oriented ZnO Rod Arrays on Si Substrates from Aqueous Solution

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Journal of Wuhan University of Technology(Materials Science) 2008年第2期23卷 189-193页

作者： liU Changsong li zhiwen ZHANG Qifeng School of Mechanical Engineering Qingdao Technological University Qingdao 266033 China Department of Electronics Peking University Beijing 100871 China

Ordered zinc oxide （ZnO） rod arrays with very high orientation were fabricated on Si substrates by using a solution method. The substrate surfaces were functionalized by Self-Assembly Monolayers （SAMs）. In the very early growth stage, the oriented ZnO crystals had already grown, which appeared to be the main reason why ZnO nanorods showed very high orientation. The un-dense and un-uniform SAMs provided a surface that was heterogeneous to ZnO nucleation. Consequently, highly oriented ZnO rods were selectively grown on the ＂coin-like＂ SAM-uncovered regions. The route developed here can provide some helpful information to control the nucleation and orientation of ZnO in aqueous solution. Also, the site-selective growth mechanisms can indicate a clue to grow patterned highly oriented ZnO nanorod arrays by the organic template.

关键词： zinc oxide (ZnO) self assembly monolayers (SAMs) crystal growth nanostructures site-selective growth solution method

Self-Assembly of Silver Clusters into One-and Two-Dimensional Structures and Highly Selective Methanol Sensing

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Research 2023年第1期2022卷 565-571页

作者： Zhaoxian Qin zhiwen li Sachil Sharma Yongwu Peng Rongchao Jin Gao li State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Department of Chemistry Carnegie Mellon UniversityPittsburghPA 15213USA College of Materials Science and Engineering and College of Chemical Engineering Zhejiang University of TechnologyHangzhou 310014China University of Chinese Academy of Sciences 100049 BeijingChina

The development of new materials for the design of sensitive and responsive sensors has become a crucial research ***,two silver cluster-based polymers(Ag-CBPs),including one-dimensional[Ag_(22)(L1)_(8)(CF_(3)CO_(2))_(14)](CH_(3)OH)_(2))n chain and two-dimensional[Ag_(12)(L2)_(2)(CO_(2)CF_(3))_(14)(H_(2)O)_(4)(AgCO_(2)CF_(3))_(4)](HNEt_(3))_(2))_(n) film,are designed and used to simulate the human nose,an elegant sensor to smells,to distinguish organic *** study the relationship between the atomic structures of Ag-CBPs determined by x-ray diffraction and the electrical properties in the presence of organic solvents(e.g.,methanol and ethanol).The ligands,cations,and the ligated solvent molecules not only play an important role in the self-assembly process of Ag-CBP materials but also determine their physiochemical properties such as the sensing functionality.

关键词： silver Highly methanol

The Impact of Pregnancy Termination before 28 Weeks of Gestation on the Overall Prevalence of Birth Defects-Shaanxi Province,China,2014-2020

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China CDC weekly 2022年第43期4卷 967-973页

作者： Min li Le Zhang Lu Gan zhiwen li Northwest Women’s and Children's Hospital Xi’an CityShaanxi ProvinceChina Institute of Reproductive and Child Health Peking UniversityBeijingChina Key Laboratory of Reproductive Health National Health Commission of the People’s Republic of ChinaBeijingChina

Introduction:The prevalence of birth defects(BDs)at≥28 gestational weeks in China has declined significantly in recent ***,a few studies have implied that the prevalence is underestimated due to pregnancies with severe BDs often being terminated before 28 weeks of *** study sought to contribute to this data conflict by determining the total prevalence of BDs throughout the entirety of pregnancies,depicting the epidemiological distribution of BDs in Shaanxi Province,and examining the impact of pregnancy termination before 28 weeks of gestation on overall BD ***:Based on data extracted from the provincial Birth Defects Surveillance Network in Shaanxi Province,from 2014 to 2020,the trends of 18 frequent,major BDs at any gestational age were ***:The total prevalence of BDs throughout pregnancy in Shaanxi Province increased significantly from 2014 to 2020,partly due to the inclusion of slight congenital heart *** was also shown that the prevalence of all major types of BD had been previously underestimated,particularly severe external BDs,anywhere from 10%to 100%due to the previous sole measurement of terminations after 28 gestational *** tube defects,however,remained one of the top five BDs with the highest total ***:The exclusion of pregnancy terminations<28 weeks of gestation resulted in a severe underestimation of the total birth prevalence of BDs,particularly severe external *** estimate the true population-level prevalence of BD better,the current BD surveillance system should include pregnancy terminations before 28 weeks of gestation.

关键词： termination Impact Defects

Tailoring optical and photocatalytic properties by single-Ag-atom exchange in Au_(13)Ag_(12)(PPh_(3))_(10)C_(l8) nanoclusters

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Nano Research 2022年第4期15卷 2971-2976页

作者： Zhaoxian Qin Song Hu Wenhua Han zhiwen li Wen Wu Xu Jingjing Zhang Gao li State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Department of Physics School of Physical Science and TechnologyNingbo UniversityNingbo 315211China CAS Key Laboratory of Colloid Interface and Chemical ThermodynamicsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Precise mono-doping of metal atom into metal particles at a specific particle position(e.g.,the central site)in a highly controllable manner is still a *** this work,we develop a highly controllable strategy for exchanging a single Ag atom into the central gold site of Au_(13)Ag_(12)(PPh_(3))_(10)C_(l8)(Ph=phenyl)***,a“pigeon-pair”cluster of{[Au_(13)Ag_(12)(PPh_(3))_(10)C_(l8)]·[Au_(12)Ag_(13)(PPh_(3))_(10)C_(l8)]}^(2+)is obtained and confirmed by electrospray ionization mass spectrometry(ESI-MS),thermogravimetric analysis(TGA)and single crystal X-ray diffraction(SCXRD)*** experimental results and density functional theory(DFT)calculations suggest that the single-metal-atom exchanging from[Au_(13)Ag_(12)(PPh_(3))_(10)C_(l8)]^(+)to[Au_(12)Ag_(13)(PPh_(3))_(10)C_(l8)]^(+)occurs at the central position through the side entry of theμ_(3)-bridging Cl ***,the effects on the electronic structure and properties caused by the single-atom exchange at the central site are shown by the enhancement of fluorescence and catalytic activity in the photocatalytic oxidation of ethanol.

关键词： single atom exchange nanoclusters photoluminescence enhancement photocatalyst of ethanol alloy clusters

Morphology effects in MnCeO_(x)solid solution-catalyzed NO reduction with CO:Active sites,water tolerance,reaction pathway

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Nano Research 2023年第5期16卷 6951-6959页

作者： Quanquan Shi Yifei Zhang zhiwen li Zhongkang Han liangliang Xu Alfons Baiker Gao li College of Science&College of Material Science and Art Design Inner Mongolia Agricultural UniversityHohhot 010018China College of Chemistry and Chemical Engineering Shenyang Normal UniversityShenyang 110034China State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Department of Chemical and Biomolecular Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea Department of Chemistry and Applied Biosciences Institute for Chemical and BioengineeringETH ZurichHönggerbergHClCH-8093 ZurichSwitzerland

Morphological effects of nanoparticles are crucial in many solid-catalyzed chemical *** herein prepared two manganese-ceria solid solutions,well-defined MnCeO_(x)nanorods and MnCeO_(x)-nanocubes,exposing preferentially(111)and(100)facets of ceria,*** incorporation of Mn dopant into ceria lattice strongly enhanced the catalytic performance in the NO reduction with ***_(x)(111)catalyst outperformed MnCeO_(x)(100)counterpart due to its higher population density of oxygen vacancy ***-situ infrared spectroscopy investigations indicated that the reaction pathway over MnCeO_(x)and pristine CeO_(2)is similar and that besides the direct pathway,an indirect pathway via adsorbed hyponitrite as an intermediate cannot be ruled out.X-ray photoelectron and Raman spectroscopies as well as first-principles density functional theory(DFT)calculations indicate that the enhanced catalytic performance of MnCeO_(x)can be traced back to its“Mn–OL(VÖ)–Mn–OL(VÖ)–Ce”*** Mn dopant strongly facilitates the formation of surface oxygen vacancies(VÖ)by liberating surface lattice oxygen(OL)via CO*+OL→CO_(2)*+VÖand promotes the reduction of NO,according to NO*+VÖ→N*+OL and 2N*→N_(2).The Mn dopant impact on both the adsorption of CO and activation of OL reveals that a balance between these two effects is critical for facilitating all reaction steps.

关键词： NO reduction with CO manganese-ceria solid solution morphology effects reaction mechanism active sites

Nanostructured Ni-MoCx:An efficient non-noble metal catalyst for the chemoselective hydrogenation of nitroaromatics

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Nano Research 2023年第7期16卷 8919-8928页

作者： Yifei Zhang zhiwen li Jingjing Zhang liangliang Xu Zhong-Kang Han Alfons Baiker Gao li Institute of Catalysis for Energy and Environment College of Chemistry and Chemical EngineeringShenyang Normal UniversityShenyang 110034China State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Department of Chemical and Biomolecular Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Department of Chemistry and Applied Biosciences Institute for Chemical and BioengineeringETH ZurichHönggerbergHClZurich CH-8093Switzerland University of Chinese Academy of Sciences Beijing 100049China

Catalysts for chemoselective hydrogenation are of vital importance for the synthesis of various important chemicals and *** we developed a simple method for preparing a highly efficient Ni-MoC_(x)nanocomposite catalyst via temperature-programmed carburization of a polyoxometalate precursor.X-ray diffraction(XRD),scanning transmission electron microscopy(STEM),X-ray photoelectron spectroscopy(XPS),and X-ray absorption spectroscopy(XAS)analyses indicate that the resulting mesoporous nanocomposite catalyst is made up of well-dispersed metallic nickel particles embedded in a MoC_(x)*** catalyst exhibits high activity and selectivity(>99%)in the hydrogenation of various substituted nitroaromatics to corresponding *** high efficiency is attributed to the intimate contact of the constituents favoring electron transfer and hydrogen *** is physisorbed on the carbide support and dissociates on the nickel particles,as evidenced by Mo K-edge X-ray absorption near-edge structure(XANES)spectra,density functional theory(DFT),and hydrogen-deuterium *** remarkable catalytic performance of the catalyst could be traced back to the synergistic interaction between the Ni particles and the carbide ***-situ infrared spectroscopy and DFT simulations indicated that the adsorption/activation of the nitro group is favored compared to that of other substituents at the aromatic *** recyclability tests,the Ni-MoC_(x)nanocomposite showed no significant loss of catalytic performance in seven consecutive runs,indicating its robust nature.

关键词： Ni-MoC_(x)nanocomposite carburization of polyoxometalate hydrogenation nitroaromatics synergistic effect

Is there an optimal time to initiate adjuvant chemotherapy to predict benefit of survival in non-small cell lung cancer?

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Chinese Journal of Cancer Research 2017年第3期29卷 263-271页

作者： Yutao liu Xiaoyu Zhai Junling li zhiwen li Di Ma Ziping Wang Department of Medical Oncology National Cancer Center/Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College Institute of Reproductive & Child Health Peking University Ministry of Health Key Laboratory of Reproductive Health Department of Epidemiology and Biostatistics School of Public Health Peking University Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing) Department of Thoracic Medical Oncology Peking University Cancer Hospital &Institute

Objective: Adjuvant chemotherapy (AC) after curative resection is known to improve the survival of patients with non-small cell lung cancer (NSCLC); however, few studies have reported the correlation between the time to initiation of AC (TTAC) and survival in NSCLC patients. Methods: The clinical data of 925 NSCLC patients who received curative resection and post-operative AC at the Cancer Hospital of Chinese Academy of Medical Sciences between 2003 and 2013 were retrospectively analyzed. TTAC was measured from the date of surgery to the initiation of AC. Disease-free survival (DFS) was defined as the duration from surgery to the time of tumor recurrence or last follow-up evaluation. The optimal cut-off value of TTAC was determined by maximally selected log-rank statistics. The DFS curve was estimated using the Kaplan-Meier method, and the Cox proportional hazards regression model was used to identify risk factors independently associated with DFS. Propensity score matching (PSM) was performed for survival analysis using the match data. Results: The optimal discriminating cut-off value of TTAC was set at d 35 after curative resection based on which the patients were assigned into two groups: group A ( 35 d). There was no significant difference in the DFS between the two groups (P=0.246), indicating that the TTAC is not an independent prognostic factor for DFS. A further comparison continued to show no significant difference in the DFS among 258 PSM pairs (P=0.283). Conclusions: There was no significant correlation between the TTAC and DFS in NSCLC patients. Studies with larger samples are needed to further verify this conclusion.

关键词： Non-small cell lung cancer (NSCLC) adjuvant chemotherapy time to adjuvant chemotherapy(TTAC) disease-free survival

Surface ligand engineering on the optical properties of atomically precise AuAg nanoclusters

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Chinese Journal of Structural Chemistry 2023年第9期42卷 1-5页

作者： Xiang liu Yifei Zhang zhiwen li Gao li Farid Taherkhani Hunan Drug Inspection Center Hunan Institute for Drug ControlChangsha410013China State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian116023China Institute of Catalysis for Energy and Environment College of Chemistry and Chemical EngineeringShenyang Normal UniversityShenyang110034China University of Chinese Academy of Sciences Beijing100049China Departments of Production Engineering Universität Bremen Bibliothekstraße 128359Germany

*** In recent decade,atomically precise metal nanoclusters,comprised of metal kernel and surface protecting ligands,have appeared as a new and promising nanomaterial for abundant applications,such as nanocatalysis,sensor,photoluminescence,a few to name,which is attributed to their electron energy quantization arising from quantum size effect[1].And the very recent investigations showed that the configuration of metal kernel and the electronic properties of metal nanoclusters with the same metal core are largely affected by the surface protecting ligands[[2],[3]].For example,the surface ligands can significantly alter the catalytic performance of metal nanocluster catalysts(*** and selectivity)in a positive *** have found that the Au_(25)(SR)_(18)nanocluster with the aromatic ligands can give higher conversions and a markedly increasing selectivity toward the desired product[4].

关键词： precise clusters selectivity