349 research outputs found
How does the G20 Summit affect land market? Evidence from China
We employ the difference-in-difference and synthetic control methods to investigate the capitalization effect of hosting the G20 Summit on land market, based on China’s land transaction dataset from 2011 to 2019. We find that hosting the G20 Summit has a significant positive effect on land prices in the host city, increasing land prices by over 22.6% compared to comparable cities. The impact of hosting the G20 Summit on land prices is larger in the post-G20 period than in the preparation period. Further, hosting the G20 Summit has heterogeneous and distributional effects on land prices. The capitalization effects of venue construction and transportation infrastructure upgrading on land prices are the main channels
From Dublin Core to MARC - Crosswalking ETD Metadata from Digital Commons to the Library Catalog
Florida International University has developed a semi-automated process for harvesting and transforming qualified Dublin Core metadata to MARC for electronic theses and dissertations published in Digital Commons for inclusion in the library catalog. This presentation will share the workflow whereby metadata is harvested via OAI-PMH; transformed to MARC using a script; and ingested into the catalog. Challenges and benefits of this workflow will be discussed.
This presentation will also share information related to our retrospective thesis and dissertation scanning project; the need to overlay existing records in the catalog with new metadata; and specific challenges related to RTDs
Fragmentation Behaviour of Radial Layered PELE Impacting Thin Metal Target Plates
The fragmentation mechanism of the penetrator with lateral effect (PELE) after perforating a thin target plate has been summarised and analysed firstly. Then the fragmentation of radial layered PELE was analysed qualitatively and verified by experiment. In the experiment, the target plates were made of 45# steel and 2A12 aluminium respectively. Qualitative analysis and experimental results show that: for normal PELE without layered, after perforating the thin metal target plate, from the bottom to the head of the projectile, the number of fragments formed by the jacket gradually increases, and the mass of the fragment decreases correspondingly. Compared with the normal PELE without layered, the radial layered PELE is less likely to break into fragments, when impacting the thin metal target plate with the same material and thickness under the same impact velocity. However, from the mechanism of the PELE, when the resistance of the target plate is large enough, and the duration of pressure is long enough, the radial layered PELE also can break into fragments with transverse velocity component. The resistance of the target plate plays an important role in the fragmentation of radial layered PELE. The radial layered PELE produced massive fragments with transverse velocity component when impacting the 45# steel plate with5 mm thickness under the impact velocity of 657.2 m/s
Simulation of Fragmentation Characteristics of Projectile Jacket Made of Tungsten Alloy after Penetrating Metal Target Plate using SPH Method
A smooth particle hydrodynamics (SPH) model was used to simulate the fragmentation process of the jacket during penetrator with lateral efficiency (PELE) penetrating the metal target plate to study the fragmentation characteristics of PELE jacket made of tungsten alloy. The validity of the SPH model was verified by experimental results. Then the SPH model was used to simulate the jacket fragmentation under different impact velocity and thickness of target plate. The influence of impact velocity and thickness of target plate on the jacket fragmentation was obtained by analysing the mass distribution and quantity distribution of the fragments formed by the jacket. The results show that the dynamic fragmentation of tungsten alloy can be simulated effectively using the SPH model, Johnson-Cook strength model, maximum tensile stress failure criterion and stochastic failure model. When the thickness of target plate is fixed, the greater the impact velocity, the greater the pressure produced by the projectile impacting the target plate; with the increase of impact velocity, the mass of residual projectile decreases, the number of fragments formed by fragmentation of jacket increases linearly, and the average mass of fragments decreases exponentially. When the impact velocity is constant, the greater the thickness of the target plate, the longer the pressure duration by the projectile impacting the target plate; with the increase of the thickness of target plate, the mass of residual projectile decreases, the number of fragments formed by fragmentation of jacket increases linearly, and the average mass of fragments decreases exponentially. The numerical calculation model and research method adopted in this paper can be used to study the impact fragmentation of solid materials effectively
Bearing Capacities of the Structure and Joint of JUNO Central Detector
The Jiangmen Underground Neutrino Observatory (JUNO) central detector will be placed underground to detect neutrinos. In order to achieve the feasible scheme for JUNO, the structural scheme of an acrylic ball supported by a double-layer stainless steel latticed shell is designed and modeled using ABAQUS software. The bearing capacity of the structure under working condition is investigated and influences of external factors are analyzed. For the purpose of studying the load-bearing behavior of the joint of acrylic and stainless steel in this scheme, tests of three joint specimens are conducted and the results are compared with finite element (FE) predictions. It is concluded that the structure is safe and reliable under the effects of external factors. The bearing capacity of the joint is at least 2 times as large as the design load and the stress on the acrylic is limited within 10MPa
A review on heterogeneous solid catalysts and related catalytic mechanisms for epoxidation of olefins with H2O2
The epoxidation reaction using heterogeneous solid catalysts with H2O2 as oxidants are environmentally friendly routes to produce extensively useful epoxides which are traditionally obtained from capital-intensive or environmentally polluted processes. In this paper, various types of solid catalysts for the epoxidation of olefins with H2O2 as oxidants are reviewed. The efficient catalysts reported include microporous and mesoporous molecular sieves, layered-type materials, inorganic oxides, supported catalysts, zeolite encapsulated metal complexes, polyoxometalates, and supported organometallic catalysts. The proposed reaction mechanisms over different solid catalysts are summarized. The problems and perspectives to further efficiently improve the catalytic performances of the concerned heterogeneous catalysts for epoxidation reaction are remarked
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