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Sequential Observation of Alkali-halide Gas Phase Clusters in High Resolution TOF-MS and Prediction of Their Structures

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Chinese Journal of Chemical Physics 2013年第6期26卷 729-738,I0004页

作者： Hui Wen Yi-rong Liu kang-ming Xu Teng Huang Chang-jin Hu wei-jun Zhang wei Huang Laboratory of Atmospheric Physico-Chemistry Anhui Institute of Optics and Fine MechanicsChinese Academy of Sciences Hefei 230031 China School of Environmental Science and Optoelectronic Technology University of Science and Technology of China Hefei 230026 China

Alkali halide clusters are interesting model systems that can provide information about how crystal properties evolve. To study these properties, a high-resolution atmospheric pressure inlet time-of-flight mass spectrometry （APi-TOF-MS） study of the sequential sodium halides series, C1-（NaC1）n and Br-（NaBr）m, has been reported, and the viability of the APi-TOF- MS equipped with an electrospray ionization source in determining cluster compositions has been demonstrated. The isotopic patterns were well resolved, as n=4 and 7 were determined to be the magic numbers for C1-（NaC1）n clusters, which were particularly abundant in the mass spectra. A global minimum search based on density functional theory enabled basin hopping yield the most stable structures for the mentioned series. The structures exhibit several distinct motifs which can be roughly categorized as linear chain, rock salt, and hexag- onal ring. This work provides an effective way to discover and elucidate the nonstoichiometry sodium halide clusters. These clusters possess very high vertical detachment energies and are generally called as superhalogens, which play important roles in chemistry because they are widely used in the synthesis of new classes of charge-transfer salts.

关键词： Atmospheric pressure interface time-of-flight mass spectrometry Density functional theory Sodium halide cluster

General interaction quenches in a Luttinger liquid

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Communications in Theoretical Physics 2022年第1期74卷 134-141页

作者： You-ming wei Hantao Lu School of Physical Science and Technology&Key Laboratory for Magnetism and Magnetic Materials of the MoE Lanzhou UniversityLanzhou 730000China Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu ProvinceLanzhou UniversityLanzhouGansu 730000China

We discuss a general interaction quench in a Luttinger liquid described by a paired bosonic *** employing su(1,1)Lie algebra,the post-quench time-evolved wavefunctions are obtained analytically,from which the time evolution of the entanglement in momentum space can be *** note that depending on the choice of Bogoliubov quasiparticles,the expressions of wavefunctions,which describe time-evolved paired states,can take different *** correspondence between the largest entanglement eigenvalue in momentum space and the wavefunction overlap in quench dynamics is discussed,which generalizes the results of Dora et al(2016,***.117,010603).A numerical demonstration on an XXZ lattice model is presented via the exact diagonalization method.

关键词： quantum quench exact diagonalization Luttinger liquid XXZ model

Preparation and corrosion resistance of the micro-arc oxidation coating on Al_2O_3f/ZL109 composites

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Rare Metals 2013年第3期32卷 290-293页

作者： ming-Chao Yu wei Liang School of Materials Science and Engineering Taiyuan University of Technology

A ceramic layer was prepared on the surface of Al2O3f/ZL109 composites by means of micro-arc oxidation （MAO） technique. The surface morphology and phase constituent of the ceramic layer were analyzed using scanning electron microscope and X-ray diffraction. The polarization curves of the composites before and after MAO treatment were measured and analyzed. The results showed that after Al2O3f/ZL109 composites were treated using MAO technique in silicate solution, the ceramic layer formed, and it was composed of Al, Si, and mullite phase. Al and Si came from Al alloy matrix of the composites, and the mullite phase formed in process of MAO. Al2O3 fiber in the composites affects the electric conductivity of the composites, the MAO reaction is promoted, and the cera- mic layer forming on the composite material side is slightly thicker than that on the Al alloy side. After Al2O3f/ZL109 composites were treated using MAO technique, the corro- sion resistance of the composites is significantly improved.

关键词： Micro-arc oxidation Al alloy composites Ceramic layer Corrosion resistance

Examples of compactλ-hypersurfaces in Euclidean spaces

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Science China Mathematics 2021年第1期64卷 155-166页

作者： Qing-ming Cheng Guoxin wei Department of Applied Mathematics Faculty of SciencesFukuoka UniversityFukuoka814-0180Japan School of Mathematical Sciences South China Normal UniversityGuangzhou510631China

In this paper,we first construct compact embeddedλ-hypersurfaces with the topology of torus which are calledλ-torus in Euclidean spacesℝn^+***,we give many compact immersedλ-hypersurfaces in Euclidean spacesℝn^+1.

关键词： the weighted area functional embeddedλ-hypersurfaces λ-torus

Feng Ligand:Privileged Chiral Ligand in Asymmetric Catalysis

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Chinese Journal of Chemistry 2021年第4期39卷 969-983页

作者： ming-Yang Wang wei Li Department of Chemistry Zhejiang UniversityHangzhouZhejiang310027 China

Catalysts and ligands possessing the great ability to tolerate over a wide range of mechanistically unrelated reactions are remarked as"privileged",which are rather scarce but extremely meaningful in asymmetric *** and co-workers have developed a library of conformationally flexible,C2-symmetric N,N'-dioxide amide compounds with original design and featured structure(named as Feng ligand now).They were initially reported as chiral organocatalysts in 2005 and have been further developed as a new class of privileged chiral ligands since *** success,including versatile coordination chemistry with plenty of metal sources(main-group metals,transition metals,and rare-earth metals),a truly broad scope of asymmetric reactions(more than 50 types),diverse areas of catalysis(organocatalysis,Lewis-acid catalysis,bimetallic relay catalysis,and photocatalysis),numerous synthetic applications of bioactive compounds,has been achieved using Feng N,N'-***,they demonstrate that chiral ligands with conformationally flexible property can offer excellent chiral environment as well,which challenges the conventional idea preferring rigid structures in the design of chiral ***,we briefly introduced the discovery of Feng ligand and the millstones during the *** also covered the successful applications of Feng ligand by other scientists as well as novel chiral ligands inspired by them.

关键词： Feng ligand N,N'-Dioxide O ligands Asymmetric catalysis Lewis acids

Dynamic mechanical behavior of ultra-high strength steel 30CrMnSiNi2A at high strain rates and elevated temperatures

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Journal of Iron and Steel Research International 2017年第7期24卷 724-729页

作者： Qiu-lin Niu wei-wei ming ming Chen Si-wen Tang Peng-nan Li College of Mechanical and Electrical Engineering Hunan University of Science and Technology Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-Cut Material Hunan University of Science and Technology School of Mechanical Engineering Shanghai Jiao Tong University

During high speed machining in the field of manufacture,chip formation is a severe plastic deformation process including large strain,high strain rate and high *** the strain rate in high speed cutting process can be achieved to 105 s^（-1）.30CrMnSiNi2Asteel is a kind of important high-strength low-alloy structural steel with wide application *** the dynamic mechanical properties of30CrMnSiNi2Aunder the conditions of high strain rate and high temperature is necessary to construct the constitutive relation model for high speed *** dynamic compressive mechanical properties of30CrMnSiNi2Asteel were studied using split Hopkinson pressure bar（SHPB）tests at 30-700°C and3000-10000s^（-1）.The stress-strain curves of 30CrMnSiNi2Asteel at different temperatures and strain rates were investigated,and the strain hardening effect and temperature effect were *** results show that 30CrMnSiNi2Ahas obvious temperature sensitivity at 300°***,the flow stress decreased significantly with the increase of *** strain hardening effect of the material at high strain rate is not significant with the increase of *** strain rate hardening effect is obvious with increasing the *** to the experimental results,the established Johnson-Cook（J-C）constitutive model of 30CrMnSiNi2Asteel could be used at high strain rate and high temperature.

关键词： 30CrMnSiNi2A steel Dynamic mechanical behavior Split Hopkinson pressure bar High temperature High strain rate Ultra-high strength steel

Evolution of Cloud Operating System： From Technology to Ecosystem

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Journal of Computer Science & Technology 2017年第2期32卷 224-241页

作者： Zuo-Ning Chen kang Chen Jin-Lei Jiang Lu-Fei Zhang Song Wu Zheng-wei Qi Chun-ming Hu Yong-wei Wu Yu-Zhong Sun Hong Tang Ao-Bing Sun Zi-Lu kang Department of Computer Science and Technology Tsinghua University Beijing 100084 China Jiangnan Institute of Computing Technology Wuxi 214083 China School of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China School of Software Shanghai Jiao Tong University Shanghai 200240 Schiena School of Computer Science and Engineering Beihang University Beijing 100191 China Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China Alibaba Cloud Computing Inc. Hangzhou 310024 China G-Cloud Technology Inc. Dongguan 523808 China Institute of Technology of Intevnet of Things Information Science Academy of China Electronics Technology Group Corporation Beijing 100081 China

The cloud operating system （cloud OS） is used for managing the cloud resources such that they can be used effectively and efficiently. And also it is the duty of cloud OS to provide convenient interface for users and applications. However, these two goals are often conflicting because convenient abstraction usually needs more computing resources. Thus, the cloud OS has its own characteristics of resource management and task scheduling for supporting various kinds of cloud applications. The evolution of cloud OS is in fact driven by these two often conflicting goals and finding the right tradeoff between them makes each phase of the evolution happen. In this paper, we have investigated the ways of cloud OS evolution from three different aspects： enabling technology evolution, OS architecture evolution and cloud ecosystem evolution. We show that finding the appropriate APIs （application programming interfaces） is critical for the next phase of cloud OS evolution. Convenient interfaces need to be provided without scarifying efficiency when APIs are chosen. We present an API-driven cloud OS practice, showing the great capability of APIs for developing a better cloud OS and helping build and run the cloud ecosystem healthily.

关键词： cloud computing operating system architecture evolution virtualization cloud ecosystem

X-ray Flashes from Off-axis Nonuniform Jets

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Chinese Journal of Astronomy and Astrophysics 2004年第5期4卷 473-480页

作者： Zhi-Ping Jin Da-ming wei Purple Mountain Observatory Chinese Academy of SciencesNanjing 210008 National Astronomical Observatories Chinese Academy of SciencesBeijing 100012

It has been widely believed that the outflows in gamma-ray bursts are jetted and some jets may have structures like ∈(θ)∝θ-k. We check the possibility that X-ray flashes come from such jets. Both qualitative and quantitative analyses have shown that this model can reproduce most of the observational features of both X-ray flashes and gamma-ray bursts. Using the usual parameters of gamma-ray bursts, we have carried out numerical calculations for both uniform and nonuniform jets, of their fluxes, spectra and peak energies. It seems that nonuniform jets are more appropriate to these observational properties than uniform jets. We have also shown that in our model the observational ratio of gamma-ray bursts to X-ray flashes is about a few units.

关键词： X-rays general-gamma rays bursts-ISM jets and outflows

Efficient modeling of cable-pulley system with friction based on arbitrary-Lagrangian-Eulerian approach

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Applied Mathematics and Mechanics(English Edition) 2017年第12期38卷 1785-1802页

作者： Yun PENG Yadong wei ming ZHOU Science and Technology Innovation Institute Dongguan University of Technology Dongguan 523808Guangdong ProvinceChina School of Aerospace Engineering Tsinghua UniversityBeijing 100084China

In conventional modeling of a cable-pulley system, the cable must be finely meshed with Lagrangian elements for valid contact detections with pulleys, leading to extremely low efficiency. The sliding joint method based on the arbitrary-Lagrangian- Eulerian （ALE） formulation still lacks an efficient cable element, and in particular, modeling of friction between a sliding joint and the cable has not been studied. This paper presents efficient multi-body modeling of a cable-pulley system with friction. A variable- length cable element with a node movable along the cable, which is described with ALE, is developed to mesh the cable. A transitional cable element is then proposed to model the contact part of the cable by fixing its two nodes to the two corresponding locations of the pulley. Friction of the cable-pulley is derived as a simple law of tension decay and embedded in the multi-body system modeling. It is simplified as a generalized friction force acting only on the arc-length coordinate. This approach can use a rough mesh on the cable, and is free of contact detections, thus significantly saving computation time. Several examples are presented to validate the proposed method, and show its effectiveness in real engineering applications.

关键词： cable-pulley system length-variable friction arbitrary-Lagrangian-Eulerian(ALE) cable tension decay dynamics