784 research outputs found

    Laser Cooling of 85Rb Atoms to the Recoil Temperature Limit

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    We demonstrate the laser cooling of 85Rb atoms in a two-dimensional optical lattice. We follow the two-step degenerate Raman sideband cooling scheme [Kerman et al., Phys. Rev. Lett. 84, 439 (2000)], where a fast cooling of atoms to an auxiliary state is followed by a slow cooling to a dark state. This method has the advantage of independent control of the heating rate and cooling rate from the optical pumping beam. We operate the lattice at a Lamb-Dicke parameter eta=0.45 and show the cooling of spin-polarized 85Rb atoms to the recoil temperature in both dimension within 2.4 ms with the aid of adiabatic cooling

    Influence of the Coriolis force in atom interferometry

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    In a light-pulse atom interferometer, we use a tip-tilt mirror to remove the influence of the Coriolis force from Earth's rotation and to characterize configuration space wave packets. For interferometers with large momentum transfer and large pulse separation time, we improve the contrast by up to 350% and suppress systematic effects. We also reach what is to our knowledge the largest spacetime area enclosed in any atom interferometer to date. We discuss implications for future high performance instruments.Comment: 4 pages, 5 figures, 1 tabl

    Building Identification to Co-Create Supply Chain Innovation

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    Supply chain identification is a process of self-categorization which can encourage firms to make more efforts to achieve supply chain goals. It is important for firms to co-create value with customers/suppliers while pursuing supply chain innovation. However, few studies have investigated identification issues from the business-to-business aspects. Therefore, the purpose of this study is to investigate the identification generation among supply chain members, especially focus on the exchange mechanisms of identification. Based on these mechanisms, we develop a research model to explain the influences of the exchange mechanisms on information sharing and supply chain innovation. This empirical study investigates the top 1000 Taiwanese manufacturers issued by Commonwealth magazine of Taiwan in 2012. The results show: (1) The exchange mechanisms, including trust, commitment, communication, and reciprocal relationship have significant effects on information sharing. (2) Information sharing in the value co-creating process has a significant effect on supply chain innovation. Implications are provided based on the results

    High-resolution atom interferometers with suppressed diffraction phases

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    We experimentally and theoretically study the diffraction phase of large-momentum transfer beam splitters in atom interferometers based on Bragg diffraction. We null the diffraction phase and increase the sensitivity of the interferometer by combining Bragg diffraction with Bloch oscillations. We demonstrate agreement between experiment and theory, and a 1500-fold reduction of the diffraction phase, limited by measurement noise. In addition to reduced systematic effects, our interferometer has high contrast with up to 4.4 million radians of phase difference, and a resolution in the fine structure constant of δα/α=0.25 \delta \alpha/\alpha=0.25\,ppb in 25 hours of integration time.Comment: Added appendix and explanations. 6 pages, 4 figure

    Existence theorems for a crystal surface model involving the p-Laplace operator

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    The manufacturing of crystal films lies at the heart of modern nanotechnology. How to accurately predict the motion of a crystal surface is of fundamental importance. Many continuum models have been developed for this purpose, including a number of PDE models, which are often obtained as the continuum limit of a family of kinetic Monte Carlo models of crystal surface relaxation that includes both the solid-on-solid and discrete Gaussian models. In this paper we offer an analytical perspective into some of these models. To be specific, we study the existence of a weak solution to the boundary value problem for the equation - \Delta e^{-\mbox{div}\left(|\nabla u|^{p-2}\nabla u\right)}+au=f, where p>1,a>0p>1, a>0 are given numbers and ff is a given function. This problem is derived from a crystal surface model proposed by J.L.~Marzuola and J.~Weare (2013 Physical Review, E 88, 032403). The mathematical challenge is due to the fact that the principal term in our equation is an exponential function of a p-Laplacian. Existence of a suitably-defined weak solution is established under the assumptions that p∈(1,2], N≤4p\in(1,2], \ N\leq 4, and f∈W1,pf\in W^{1,p}. Our investigations reveal that the key to our existence assertion is how to control the set where -\mbox{div}\left(|\nabla u|^{p-2}\nabla u\right) is ±∞\pm\infty

    FACTORS AFFECTING THE TRANSFER OF INTER-ORGANIZATIONAL SYSTEMS TO CHINA: A CASE STUDY OF HIGH-TECH ENTERPRISES

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    Due to the huge market potentiality, profuse production resource such as workforce and land, and low production costs in China, many international high-tech enterprises are moving their production line to China. Accompanying production offshoring is the transfer of Information Technology (IT) to ensure that the production processes remain efficient and effective at home and abroad. Many enterprises however encounter problems in transferring their IT to China, especially when the IT is an inter-organizational system (IOS), which is across organizational boundaries and involves the management of relationships among participants. In order to understand how to successfully transfer IOS to China, we aim to find out key relational factors of IOS performance in China through an observation of a binary relationship built upon an e-procurement system between a Taiwanese PC ODM (Original Design Manufacturer) and its Chinese suppliers. Based on the relational view of the firm, four relational factors are proposed and examined. The results show that IOS specific investments and effective IOS governance most strongly affects the result of IOS transfer to China, whereas complementary resource endowment has least influence

    On several partitioning problems of Bollobás and Scott

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    AbstractJudicious partitioning problems on graphs and hypergraphs ask for partitions that optimize several quantities simultaneously. Let G be a hypergraph with mi edges of size i for i=1,2. We show that for any integer k⩾1, V(G) admits a partition into k sets each containing at most m1/k+m2/k2+o(m2) edges, establishing a conjecture of Bollobás and Scott. We also prove that V(G) admits a partition into k⩾3 sets, each meeting at least m1/k+m2/(k−1)+o(m2) edges, which, for large graphs, implies a conjecture of Bollobás and Scott (the conjecture is for all graphs). For k=2, we prove that V(G) admits a partition into two sets each meeting at least m1/2+3m2/4+o(m2) edges, which solves a special case of a more general problem of Bollobás and Scott

    A comparative study on the dependence potential of thienorphine and buprenorphine

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    Background: As part of research to discover partial opioid agonists for new treatments of opioid abuse and dependency, thienorphine, a buprenorphine analogue, was synthesised and reported to be a potent, long-acting oripavine in multiple mammalian models. Thienorphine binds non-selectively to μ-, δ-, and κ-opioid receptors, and partially stimulates μ- and/or κ-opioid receptors in vitro. Compared with buprenorphine, thienorphine exhibits better analgesic effects and has higher oral bioavailability. Poor oral absorption and dependence have hindered the use of buprenorphine for detoxification therapy and relapse prevention in the clinic. The addiction potential of thienorphine is unknown, and is worthy of in-depth investigation. Methods: In the present study, we conducted a comparison of thienorphine and buprenorphine with respect to their physical and psychological dependence liabilities, using a naloxone-induced withdrawal test, a conditioned place preference test, and a self-administration experiment in rats. Results: In contrast to chronic buprenorphine administration, we failed to observe any severe abstinence syndromes in mice or rats treated with thienorphine after naloxone challenge in a physical dependence model. Compared with the dependence potentials of buprenorphine, rats treated with chronic thienorphine did not show a place conditioning response, self-administration, or psychological dependence. Conclusions: We demonstrated that thienorphine has a lower potential than buprenorphine for physical and psychological dependence. Our results indicate that thienorphine might be a good candidate to treat opioid addiction

    HandDiffuse: Generative Controllers for Two-Hand Interactions via Diffusion Models

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    Existing hands datasets are largely short-range and the interaction is weak due to the self-occlusion and self-similarity of hands, which can not yet fit the need for interacting hands motion generation. To rescue the data scarcity, we propose HandDiffuse12.5M, a novel dataset that consists of temporal sequences with strong two-hand interactions. HandDiffuse12.5M has the largest scale and richest interactions among the existing two-hand datasets. We further present a strong baseline method HandDiffuse for the controllable motion generation of interacting hands using various controllers. Specifically, we apply the diffusion model as the backbone and design two motion representations for different controllers. To reduce artifacts, we also propose Interaction Loss which explicitly quantifies the dynamic interaction process. Our HandDiffuse enables various applications with vivid two-hand interactions, i.e., motion in-betweening and trajectory control. Experiments show that our method outperforms the state-of-the-art techniques in motion generation and can also contribute to data augmentation for other datasets. Our dataset, corresponding codes, and pre-trained models will be disseminated to the community for future research towards two-hand interaction modeling

    Causal Mediation Analysis for Difference-in-Difference Design and Panel Data

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    Advantages of panel data, i.e., difference in difference (DID) design data, are a large sample size and easy availability. Therefore, panel data are widely used in epidemiology and in all social science fields. The literatures on causal inferences of panel data setting or DID design are growing, but no theory or mediation analysis method has been proposed for such settings. In this study, we propose a methodology for conducting causal mediation analysis in DID design and panel data setting. We provide formal counterfactual definitions for controlled direct effect and natural direct and indirect effect in panel data setting and DID design, including the identification and required assumptions. We also demonstrate that, under the assumptions of linearity and additivity, controlled direct effects can be estimated by contrasting marginal and conditional DID estimators whereas natural indirect effects can be estimated by calculating the product of the exposure-mediator DID estimator and the mediator-outcome DID estimator. A panel regression-based approach is also proposed. The proposed method is then used to investigate mechanisms of the effects of the Covid 19 pandemic on the mental health status of the population. The results revealed that mobility restrictions mediated approximately 45 % of the causal effect of Covid 19 on mental health status
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