10 research outputs found

    Semiclassical LpL^p quasimode restriction estimates in two dimensions

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    We establish the LpL^p restriction estimates for quasimodes on a smooth curve in two dimensions. Our estimates are sharp for all smooth curves. As an application, we address LpL^p eigenfunction restriction estimates for Laplace-Beltrami eigenfunctions on 22-dimensional compact Riemannian manifolds without boundary and Hermite functions on R2\mathbb R^2. Our method involves a geometric analysis of the contact order between the curve and the bicharacteristic flow of the semiclassical pseudodifferential operator.Comment: 42 pages, 2 figure

    Spherical maximal functions on two step nilpotent Lie groups

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    Consider Rd×Rm\mathbb R^d\times \mathbb R^m with the group structure of a two-step nilpotent Lie group and natural parabolic dilations. The maximal function originally introduced by Nevo and Thangavelu in the setting of the Heisenberg group deals with noncommutative convolutions associated to measures on spheres or generalized spheres in Rd\mathbb R^d. We drop the nondegeneracy condition in the known results on M\'etivier groups and prove the sharp LpL^p boundedness result for all two step nilpotent Lie groups with d3d\ge 3.Comment: 29 page

    Bounds on the Hermite spectral projection operator

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    We study LpL^p-LqL^q bounds on the spectral projection operator Πλ\Pi_\lambda associated to the Hermite operator H=x2ΔH=|x|^2-\Delta in Rd\mathbb R^d. We are mainly concerned with a localized operator χEΠλχE\chi_E\Pi_\lambda\chi_E for a subset ERdE\subset\mathbb R^d and undertake the task of characterizing the sharp LpL^p--LqL^q bounds. We obtain sharp bounds in extended ranges of p,qp,q. First, we provide a complete characterization of the sharp LpL^p--LqL^q bounds when EE is away from λSd1\sqrt{\lambda}\mathbb S^{d-1}. Secondly, we obtain the sharp bounds as the set EE gets close to λSd1\sqrt\lambda\mathbb S^{d-1}. Thirdly, we extend the range of p,qp,q for which the operator Πλ\Pi_\lambda is uniformly bounded from Lp(Rd)L^p(\mathbb R^d) to Lq(Rd)L^q(\mathbb R^d).Comment: The paper is a modified version of a part of the paper Hermite spectral projection operator (arXiv:2006.11762v3). The previous paper will remain unpublishe

    Bochner-Riesz mean for the twisted Laplacian in R2\mathbb R^2

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    We study the Bochner-Riesz problem for the twisted Laplacian L\mathcal L on R2\mathbb R^2. For p[1,]{2}p\in [1, \infty]\setminus\{2\}, it has been conjectured that the Bochner-Riesz means Sλδ(L)fS_\lambda^\delta(\mathcal L) f of order δ\delta converges in LpL^p for every fLpf\in L^p if and only if δ>max(0,(p2)/p1/2)\delta> \max(0,|(p-2)/p|-1/2). We prove the conjecture by obtaining uniform LpL^p bounds on Sλδ(L)S_\lambda^\delta(\mathcal L) up to the sharp summability indices.Comment: 15 page

    NOVEL TWO-INTERCONNECTED FLUIDIZED BED SYSTEM FOR SELECTIVE SOLID CIRCULATION

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    A novel two-interconnected fluidized bed system was developed to separate fine and coarse particles by means of particle size difference. Coarse (212~300 μm) and fine (63~106 μm) particles were separated perfectly using the solid separator. The effects of the fluidizing velocity, solid injection velocity, diameter of solid injection nozzle, and solid height on the solid separation rate were investigated. Moreover, continuous solid separation and circulation test up to 20 hours was performed to check feasibility of stable operation

    Effects of Crystalline Disorder on Interfacial and Magnetic Properties of Sputtered Topological Insulator/Ferromagnet Heterostructures

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    Thin films of Topological insulators (TIs) coupled with ferromagnets (FMs) are excellent candidates for energy-efficient spintronics devices. Here, the effect of crystalline structural disorder of TI on interfacial and magnetic properties of sputter-deposited TI/FM, Bi2Te3/Ni80Fe20, heterostructures is reported. Ni and a smaller amount of Fe from Py was found to diffuse across the interface and react with Bi2Te3. For highly crystalline c-axis oriented Bi2Te3 films, a giant enhancement in Gilbert damping is observed, accompanied by an effective out-of-plane magnetic anisotropy and enhanced damping-like spin-orbit torque (DL-SOT), possibly due to the topological surface states (TSS) of Bi2Te3. Furthermore, a spontaneous exchange bias is observed in hysteresis loop measurements at low temperatures. This is because of an antiferromagnetic topological interfacial layer formed by reaction of the diffused Ni with Bi2Te3 which couples with the FM, Ni80Fe20. For increasing disorder of Bi2Te3, a significant weakening of exchange interaction in the AFM interfacial layer is found. These experimental results Abstract length is one paragraph

    Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

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    Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049

    Sharp Lp-Lq estimate for the spectral projection associated with the twisted Laplacian

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    In this note we are concerned with estimates for the spectral projection operator Pµ associated with the twisted Laplacian L. We completely characterize the optimal bounds on the operator norm of Pµ from Lp to Lq when 1 ≤ p ≤ 2 ≤ q ≤ ∞. As an application, we obtain a uniform resolvent estimate for L

    Endpoint eigenfunction bounds for the Hermite operator

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    We establish the optimal LpL^p, p=2(d+3)/(d+1),p=2(d+3)/(d+1), eigenfunction bound for the Hermite operator H=Δ+x2\mathcal H=-\Delta+|x|^2 on Rd\mathbb R^d. Let Πλ\Pi_\lambda denote the projection operator to the vector space spanned by the eigenfunctions of H\mathcal H with eigenvalue λ\lambda. The optimal L2L^2--LpL^p bounds on Πλ\Pi_\lambda, 2p2\le p\le \infty, have been known by the works of Karadzhov and Koch-Tataru except p=2(d+3)/(d+1)p=2(d+3)/(d+1). For d3d\ge 3, we prove the optimal bound for the missing endpoint case. Our result is built on a new phenomenon: improvement of the bound due to asymmetric localization near the sphere λSd1\sqrt\lambda \mathbb S^{d-1}.Comment: The paper is an extended revision of a part of the paper Hermite spectral projection operator (arXiv:2006.11762) where the endpoint results were established for d5d\ge 5. The earlier paper will remain unpublishe
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