93 research outputs found

    Momentum-Space Spin Antivortex and Spin Transport in Monolayer Pb

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    Non-trivial momentum-space spin texture of electrons can be induced by spin-orbit coupling and underpins various spin transport phenomena, such as current-induced spin polarization and spin Hall effect. In this work, we find a non-trivial spin texture, spin anti-vortex, can appear at certain momenta on the Γ−K\Gamma-\text K line in 2D monolayer Pb on top of SiC. Different from spin vortex due to the band degeneracy in the Rashba model, the existence of this spin anti-vortex is guaranteed by Poincare-Hopf theorem and thus topologically stable. Accompanied with this spin anti-vortex, a Lifshtiz transition of Fermi surfaces occur at certain momenta on the K−M\text K- \text M line, and both phenomena are originated from the anti-crossing between the j=1/2j=1/2 and j=3/2j=3/2 bands. A rapid variation of the response coefficients for both the current-induced spin polarization and spin Hall conductivity is found when the Fermi energy is tuned around the spin anti-vortex. Our work demonstrates the monolayer Pb as a potentially appealing platform for spintronic applications

    Chinese patent medicine as adjuvant for mild-to-moderate active ulcerative colitis : a network meta-analysis of randomized controlled trials

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    Objective. To evaluate the effectiveness and safety of Chinese patent medicine for mild-to-moderate active ulcerative colitis (UC) using network meta-analysis (NMA). Methods. We systematically searched PubMed, Cochrane library, Embase, Sino-Med, China National Knowledge Infrastructure (CNKI), Wanfang, and Chinese Scientific Journal Database (VIP) databases to October, 2020. We included randomized controlled trials (RCTs) on Chinese patent medicine for mild-to-moderate active UC. The main analysis was complemented by network subanalyses and standard pairwise comparisons. Statistical heterogeneity, inconsistencies, and ranking probability were also evaluated. Results. The databases search identified 3222 citations, of which 33 RCTs involving 2971 patients met the inclusion criteria. A total of 15 Chinese patent medicines were analyzed. The overall quality of the included studies was low. Pairwise meta-analysis showed that Chinese patent medicine was superior to Mesalazine in improving disappearances of clinical symptoms, recurrence rate, and Mayo score. Based on decreases in adverse events, results from NMA showed that Xilei powder plus Mesalazine was more effective than other drugs. Other NMA results indicated that Danshen freeze-dried powder plus Mesalazine (RR: 0.13; 95% CI, 0.02–0.78) and Kangfuxin lotion plus Mesalazine (RR: 0.24; 95% CI, 0.07–0.57) were superior to Mesalazine in decreasing recurrence rate. Another NMA result indicated that Kangfuxin lotion plus Mesalazine (RR: 0.00; 95% CI, 0.00–0.02) and Zhi Kang capsule plus Mesalazine (RR: 0.00; 95% CI, 0.00–0.02) were superior to Mesalazine in increasing the disappearance of tenesmus. Conclusion. In the probability sorting, Xilei powder combined with Mesalazine ranked first for having the fewest adverse events, Maintaining Intestines Antidiarrheal Pills combined with Mesalazine ranked first for having the lowest recurrence rate, Xilei powder combined with Mesalazine ranked first for improving disappearance rate of mucopurulent bloody stool/abdominal pain, and Kangfuxin lotion combined with Mesalazine ranked first for improving the disappearance rate of diarrhea/tenesmus. However, there is a lack of direct comparisons among Chinese patent medicines for UC. More multiarm RCTs are needed in the future to provide direct comparative evidence

    The progress of pulmonary artery denervation

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    Pulmonary arterial hypertension (PAH) is a chronic pulmonary vascular disease characterized by increased pulmonary arterial pressure and pulmonary arterioles remodeling. Some studies have discovered the relationship between sympathetic nerves (SNs) and pathogenesis of PAH. This review is aimed to illustrate the location and components of SNs in the pulmonary artery, along with different methods and effects of pulmonary artery denervation (PADN). Studies have shown that the SNs distributed mainly around the main pulmonary artery (MPA) and pulmonary artery (PA) bifurcation. And the SNs could be destroyed by three ways: the chemical way, the surgical way and the catheter-based way. PADN can significantly decrease pulmonary arterial pressure rapidly, improve hemodynamic varieties, and then palliate PAH. PADN has been recognized as a prospective and effective therapy for PAH patients, especially for those with medication-refractory PAH. However, further enlarged clinical studies are needed to confirm accurate distribution of SNs in the pulmonary artery and the efficacy of PADN

    Emergent Spin Phenomena in Air-Stable, Atomically Thin Lead

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    A stable platform to synthesize ultrathin heavy metals, with a strong interfacial Rashba effect, could lead to high efficiency charge-to-spin conversion for next-generation spintronics. Here we report wafer-scale synthesis of air-stable, epitaxially registered monolayer Pb on SiC (0001) via confinement heteroepitaxy (CHet). The highly asymmetric interfacial bonding in this heavy metal system lends to strong Rashba spin-orbit coupling near the Fermi level. Additionally, the system's air stability enables ex-situ spin torque ferromagnetic resonance (ST-FMR) measurements that demonstrate charge-to-spin conversion in CHet-based 2D-Pb/ferromagnet heterostructures and a 1.5x increase in the effective field ratio compared to control samples.Comment: 17 pages, 4 figures. Supporting Information included (20 pages, 9 figures, 1 table

    Resilient PNT Concept Frame

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    The concept of resilient positioning, navigation and timing (PNT) is described.The definition of resilient PNT is given from the point of view of sensors integration, functional model and stochastic model.The relationship between the integrated (or comprehensive) PNT and resilient PNT is analyzed. It is pointed out that the integrated PNT is the foundation of the resilient PNT.The resilient PNT should be divided into the resilient sensors integration, resilient functional model and resilient stochastic model.The strategy and the principle of resilient integration of sensors are discussed.The resilient integration of sensors should be designed following the optimal, available and compatible as well as interoperable principles.The concepts of resilient functional model and the possible modification strategies of the resilient functional model are also described.Several possible optimal routes for resilient stochastic model improvements are also set forth.It is also pointed out that the optimal improvements of stochastic models for multi PNT sources should follow the same variance scale.At last, the resilient PNT data fusion for state parameters are given based on the resilient functional and stochastic models

    Progress, Contribution and Challenges of Compass/Beidou Satellite Navigation System

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    Satellite navigation has stepped into the era of a hundred flowers in bloom. The progress, application, con-tribution and challenges of Compass/Beidou satellite system is reviewed and analyzed. Firstly, the construction prin-ciples and development steps are introduced. Secondly, the general realizations of signal frequency and the coordi-nate system as well as the time system of Beidou satellite navigation system in the frame of compatibility and interop-erability are described. Thirdly, in the concept of redundancy, the main contributions of Beidou system are analyzed. At last, the applications and the main challenges of Beidou system are reviewed

    Concepts of Comprehensive PNT and Related Key Technologies

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    The core idea of comprehensive positioning, navigation and time (PNT) is the technique that uses all the available resources to provide PNT services in the whole area, including inside and outside door, air, space, under water and underground, which does not solely rely on the GNSS. The definition and basic concepts of the comprehensive PNT are presented. The possible signal sources are listed. The core technologies related to the comprehensive PNT are analyzed, including the integration of the multiple sensors and adaptive data fusion for multiple PNT signals. It is emphasized that the information of the comprehensive PNT should be from "multiple sources based on different physical principles", the control system should be operated by voluntary users based on cloud platform, the user terminals or sensors should be "deeply integrated" and the PNT information should be "adaptively fused" and serve mode might be based on cloud platform. The comprehensive PNT system should meet the robust availability, continuity, high accuracy and reliability with unified geodetic datum and time datum

    Development of Comprehensive PNT and Resilient PNT

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    Any single Positioning, Navigation and Timing (PNT) technology has its vulnerability and limits, even the powerful Global Navigation Satellite System (GNSS) is no exception. To provide continuous and reliable PNT information to users, the theory and technique of comprehensive PNT information system and resilient PNT application system have attracted great attention from Chinese scholars. We try to summarize the progress and development of the synthetic PNT system, including the proposal, the modification and the improvement of the comprehensive PNT, as well as the follow-up resilient PNT. The frame of China’s comprehensive PNT system consisted of comprehensive PNT infrastructure and comprehensive PNT application system is initially described; the achievements on some main PNT technologies are introduced; the conceptual models of resilient PNT are given; besides, existing researches on resilient function models and stochastic models are summarized according to different user scenarios
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