3,935 research outputs found
Speculative trading, price pressure and overvaluation
No full textPrior theoretical studies (e.g., Harrison and Kreps, 1978) show that investors pay prices over their valuation of assets if potential buyers are willing to pay even more in the future. This study provides supporting evidence by focusing on the Hong Kong “through train” scheme in August 2007, through which mainland Chinese investors were allowed to directly invest in Hong Kong market, but the decision was reassessed (actually suspended) in November 2007. Our findings show that Hong Kong stocks exhibit excess trading volume associated with the two announcements, and stocks are traded higher after the launch-decision day and lower after the reassessment-decision day
Leptogenesis and residual CP symmetry
No full textWe discuss flavour dependent leptogenesis in the framework of lepton flavour models based on discrete flavour and CP symmetries applied to the type-I seesaw model. Working in the flavour basis, we analyse the case of two general residual CP symmetries in the neutrino sector, which corresponds to all possible semi-direct models based on a preserved Z 2 in the neutrino sector, together with a CP symmetry, which constrains the PMNS matrix up to a single free parameter which may be fixed by the reactor angle. We systematically study and classify this case for all possible residual CP symmetries, and show that the R-matrix is tightly constrained up to a single free parameter, with only certain forms being consistent with successful leptogenesis, leading to possible connections between leptogenesis and PMNS parameters. The formalism is completely general in the sense that the two residual CP symmetries could result from any high energy discrete flavour theory which respects any CP symmetry. As a simple example, we apply the formalism to a high energy S 4 flavour symmetry with a generalized CP symmetry, broken to two residual CP symmetries in the neutrino sector, recovering familiar results for PMNS predictions, together with new results for flavour dependent leptogenesis
Wuhan pulsed high magnetic field center
No full textWuhan pulsed high magnetic field facility is under development. Magnets of bore sizes from 12 to 34 mm with the peak field in the range of 50 to 80 T have been designed. The pulsed power supplies consists of a 12 MJ, 25 kV capacitor bank and a 100 MVA/100 MJ flywheel pulse generator. A prototype 1 MJ, 25 kV capacitor bank is under construction. Five magnets wound with CuNb wire and copper wire reinforced internally with Zylon fiber composites and externally with stainless steel shells have been developed to be tested to verify the design. The design and analysis of the power supplies, the pulsed magnets and the inductors for the protection of the thyristor switches are presented in this paper.sponsorship: Liang Li; Tao Peng; Hongfa Ding; Xiaotao Han; Zhengcai Xia; Tonghai Ding; Jin Chen; Junfeng Wang; Jianfeng Xie; Shaoliang Wang; Xianzhong Duan; Cheng Wang; Yuan Pan; Pulsed High Magn. Field Center, Huazhong Univ. of Sci. & Technol., Wuhan, Chinastatus: Publishe
Pareto-optimal multi-agent cooperative caching relying on multi-policy reinforcement learning
No full textGiven the popularity of flawless telepresence and the resultants explosive growth of wireless video applications, besides handling the traffic surge, satisfying the demanding user requirements for video qualities has become another important goal of network operators. Inspired by this, cooperative edge caching intrinsically amalgamated with scalable video coding is investigated. Explicitly, the concept of a Pareto-optimal semidistributed multi-agent multi-policy deep reinforcement learning (SD-MAMP-DRL) algorithm is conceived for managing the cooperation of heterogeneous network nodes. To elaborate, a multi-policy reinforcement learning algorithm is proposed for finding the Pareto-optimal policies during the training phase, which balances the tele-traffic vs. the user experience trade-off. Then the optimal policy/solution can be activated during the execution phase by appropriately selecting the associated weighting coefficient according to the dynamically fluctuating network traffic load. Our experimental results show that the proposed SD-MAMP-DRL algorithm 1) achieves better performance than the benchmark algorithms; 2) obtains a near-complete Paretofront in various scenarios and selects the optimal solution by adaptively adjusting the above-mentioned pair of objectives
Excited-State Dynamics of the Metal String Complex Co(3)(dpa)(4)(NCS)(2) from Femtosecond Transient Absorption Spectra
No full textA Data-driven base station sleeping strategy based on traffic prediction
No full textDue to the rapidly increasing number of base stations (BSs) in the operational cellular networks, their energy consumption is escalating. In this paper, we propose an intelligent data-driven BS sleeping mechanism relying on a wireless traffic prediction model that measures the BSs' capacity in different regions. Firstly, a spatio-temporal cellular traffic prediction model is proposed, where a multi-graph convolutional network (MGCN) is developed to capture the associated spatial features. Furthermore, a multi-channel long short-term memory (LSTM) solution involving hourly, daily and weekly periodic data is used to capture the relevant temporal features. Secondly, the capacities of macro-cell BSs (MBSs) and small-cell BSs (SBSs) having different environment characteristics are modeled, where both clustering and transfer learning algorithms are adopted for quantifying the traffic supported by the MBSs and SBSs. Finally, an optimal BS sleeping strategy is proposed for minimizing the network's power consumption. Experimental results show that the proposed MGCN-LSTM model outperforms the existing models in terms of its cellular traffic prediction accuracy, and the proposed BS sleeping strategy using an approximated non-linear model of the associated capacity function achieves near-maximal energy-saving at a modest complexity
A comprehensive assessment of empirical potentials for carbon materials
No full text© 2021 Author(s).Carbon materials and their unique properties have been extensively studied by molecular dynamics, thanks to the wide range of available carbon bond order potentials (CBOPs). Recently, with the increase in popularity of machine learning (ML), potentials such as Gaussian approximation potential (GAP), trained using ML, can accurately predict results for carbon. However, selecting the right potential is crucial as each performs differently for different carbon allotropes, and these differences can lead to inaccurate results. This work compares the widely used CBOPs and the GAP-20 ML potential with density functional theory results, including lattice constants, cohesive energies, defect formation energies, van der Waals interactions, thermal stabilities, and mechanical properties for different carbon allotropes. We find that GAP-20 can more accurately predict the structure, defect properties, and formation energies for a variety of crystalline phase carbon compared to CBOPs. Importantly, GAP-20 can simulate the thermal stability of C60 and the fracture of carbon nanotubes and graphene accurately, where CBOPs struggle. However, similar to CBOPs, GAP-20 is unable to accurately account for van der Waals interactions. Despite this, we find that GAP-20 outperforms all CBOPs assessed here and is at present the most suitable potential for studying thermal and mechanical properties for pristine and defective carbon.11Nsciescopu
The Formation of Lineages in mid-Ming Period Zhangzhou, Fujian : The Case of the Ding Lineage of Baishi Village, Longxi County
No full textThis article focuses on the specific case of the Ding Clan of Baishi Village, Longxi 龍渓 County, Zhangzhou Prefecture, Fujian Province, in an attempt to understand the meaning of clan histories contained in lineage genealogies during the mid-Ming Period.
The author begins her investigation with a discussion of the ancestral shrine built by the Dings at Wenfengmuzhong 文峰畝中 during the 7th year of the mid-Ming Period’s Zhengde Era (1512), which played an important function in maintaining clan solidarity, symbolized by the memorialized merger between the Xiangxian Sublineage (Xiangxianfang 郷賢房) of the descendants of Ding Zhiji 丁知幾, who during the Southern Song Period was awarded in his old age with the honorary title of tezouming jinshi 特奏名進士, and the Gongyuan Sublineage (Gongyuanfang 貢元房) of the descendants of Zhiji’s older brother Ding Zhiwei 丁知微, who placed first in his local civil service examination (gongyuan 貢元).
Next, the author turns to the meaning of the above merger between the two Ding sublineages. For Xiangxianfang, their social status in local society was already guaranteed by a stone inscription written by Wang Zhongqian 王仲謙, the chief executive of Zhongzhou Prefecture, lauding the accomplishments of Ding Zhiji and Xinglici 興利祠, a shrine commemorating Zhiji’s contributions to society. On the other hand, Gongyuanfang had lagged behind Xiangxianfang and were embarking on upward social mobility only from the mid-Ming Period on. One way for the latter to guarantee higher social position was their enthusiastic promotion of a merger with Xiangxianfang, by reminding them that their ancestor was the older brother of theirs and conflating Ding Zhiwei’s achievements with those of Ding Zhiji in the genealogical record. Consequently, the new Ding Clan would claim origins based on the authority of the two brothers.
Finally the author examines narrative regarding the economic base of the Ding Clan. The genealogical record tells us that the wealth earned by the Ding Clan in its commercial activities was reinvested both in the Clan as a whole and in local society. Through such stories of largess, the Clan defended the legitimacy of the privileges it enjoyed in local society from an economic perspective. Here the founding ancestor Jiuchenshilang 九承事郎 and ancestors dating back to the Tang and Song Periods were brought up to add a long historical tradition to the economic activities of the Ding Clan.
While praising its founding ancestor as a participant in the pacification and colonization of Zhangzhou by Tang Dynasty General Cheng Yuanguang 陳元光, the narrative also established Jiuchenshilang as already residing in the region prior to the entry of General Cheng, thus exploiting the authority of Cheng to claim superiority over all the other clans of Zhangzhou.journal articl
3-(tert-Butoxycarbonyl)-2-(4-chlorophenyl)-1,3-thiazolidine-4-carboxylic acid. Corrigendum
No full textThe author list in the paper by Ding [Acta Cryst. (2010), E66, o2633] is corrected
Continuous epitaxy of single-crystal graphite films by isothermal carbon diffusion through nickel
No full textMultilayer van der Waals (vdW) film materials have attracted extensive interest from the perspective of both fundamental research' and technology(4-7). However, the synthesis of large, thick, single-crystal vdW materials remains a great challenge because the lack of out-of-plane chemical bonds weakens the epitaxial relationship between neighbouring layers'. Here we report the continuous epitaxial growth of single-crystal graphite films with thickness up to 100,000 layers on high-index, single-crystal nickel (Ni) foils. Our epitaxial graphite films demonstrate high single crystallinity, including an ultra-flat surface, centimetre-size single-crystal domains and a perfect AB-stacking structure. The exfoliated graphene shows excellent physical properties, such as a high thermal conductivity of similar to 2,880 W m(-1) K-1, intrinsic Young's modulus of similar to 1.0 TPa and low doping density of similar to 2.2 x 10(10) cm(-2). The growth of each single-crystal graphene layer is realized by step edge-guided epitaxy on a high-index Ni surface, and continuous growth is enabled by the isothermal dissolution-diffusion-precipitation of carbon atoms driven by a chemical potential gradient between the two Ni surfaces. The isothermal growth enables the layers to grow at optimal conditions, without stacking disorders or stress gradients in the final graphite. Our findings provide a facile and scalable avenue for the synthesis of high-quality, thick vdW films for various applications
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