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We give the necessary and sufficient condition of the trace function f (A, B) = Tr(A(P)B(Q)) is jointly convex in (A, B). (C) 2004 Elsevier Inc. All rights reserved.
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Salt accumulation gradually changes the cycling of carbon (C), nitrogen (N), and phosphorus (P) and may even transform sinks into sources in arid wetlands. However, it's not clear how hydrochemical characteristics affect the wetla...
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Salt accumulation gradually changes the cycling of carbon (C), nitrogen (N), and phosphorus (P) and may even transform sinks into sources in arid wetlands. However, it's not clear how hydrochemical characteristics affect the wetland's source or sink function or how they affect C, N, and P cycling in arid regions. To clarify these relationships, we conducted field measurement in arid northern China. We simulated the variations of hydrochemical characteristics and the storage and stoichiometry of C, N, and P using the process-based DeNitrification-DeComposition (DNDC) and Hydrus-1D models. The meteorological and hydrological processes had obvious characteristics of seasonal and interannual changes. The measured evapotranspiration averaged 660.23 and 587.94 mm year~(?1) in the saltmarsh and riparian wetlands, respectively. The soil showed a clear trend with higher SO_4~(2?), Na~+, Ca~(2+), and Cl~? fractions in comparison with lower Mg~(2+), K~+, and HCO_3~? fractions, with the major ion and nutrient concentrations gradually decreasing with increasing depth in the soil. The major ion types had characteristics of Na~+-Ca~(2+)-SO_4~(2?)-Cl~? in the saltmarsh wetland and riparian wetland. The storage of total C, N, and P were 372.72 ± 66.52 t C/hm~2, 10.92 ± 2.59 t N/hm~2, and 17.55 ± 1.54 t P/hm~2 in the saltmarsh wetland versus 119.72 ± 27.88 t C/hm~2, 4.38 ± 1.24 t N/hm~2, and 13.17 ± 1.46 t P/hm~2 in the riparian wetland. Therefore, wetland salinization in our study led to increased soil C, N, and P contents and storage and thereby enhanced the sink function of the wetlands.
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The National School on Neutron and X-ray Scattering (NXS) is usually an onsite 2-week school held jointly by Argonne National Laboratory (ANL) and Oak Ridge National Laboratory (ORNL), making extensive use of the X-ray facilities ...
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The National School on Neutron and X-ray Scattering (NXS) is usually an onsite 2-week school held jointly by Argonne National Laboratory (ANL) and Oak Ridge National Laboratory (ORNL), making extensive use of the X-ray facilities of the Advanced Photon Source (APS) and the neutron facilities of the High Flux Isotope Reactor (HFIR) and the Spallation Neutron Source (SNS). From its inception back in 1999, the aim of the school was to provide graduate students a broad foundation in the fundamentals of both neutron and X-ray scattering techniques and to provide hands-on training on the instruments to prepare them to be future users of large-scale neutron and X-ray facilities. For the first 21 years, the schedule was lectures in the morning followed by hands-on experiments at various X-ray and neutron instruments in the afternoons.
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State estimation of linear time-invariant (LTI) systems by using a network of distributed observers is studied in this paper. We assume that each observer has access to a local measurement which may be insufficient to provide the ...
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State estimation of linear time-invariant (LTI) systems by using a network of distributed observers is studied in this paper. We assume that each observer has access to a local measurement which may be insufficient to provide the observability of the system, but the ensemble of all measurements in the network guarantees the observability. In this condition, the objective is to design a distributed state estimation approach such that, while the observers can exchange their estimated state vectors under a communication network, the estimated state vector of each observer converges to the state vector of the system. We consider a scenario when the communication links may fail and rebuild over time and the communication network does not stay connected constantly. Accordingly, the main contribution of the paper is to propose a distributed approach (with guarantees on the feasibility of the design) such that the state vector of the system is estimated by each observer if the union/joint of communication links in bounded intervals of time makes the network communication graph connected. Moreover, we also consider a scenario when the LTI system is subject to external disturbances and measurement noise. In this case, we derive sufficient conditions on the proposed approach such that if the communication topology stays connected during links failure, a desired H_∞ performance to attenuate the effect of external disturbances and measurement noise on estimation errors is guaranteed. Simulation results show the effectiveness of the proposed estimation approach.
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I have had the privilege of mentoring undergraduates in a summer REU program, held jointly by SUNY Potsdam and Clarkson University, for many summers. Working as an REU advisor has been a lot of fun, and a good change of pace from ...
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I have had the privilege of mentoring undergraduates in a summer REU program, held jointly by SUNY Potsdam and Clarkson University, for many summers. Working as an REU advisor has been a lot of fun, and a good change of pace from the very busy, teaching-heavy, 12-hour teaching semesters that we have at SUNY Potsdam. Below are some observations I have gleaned through my involvement with REUs over the years.
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A meeting on Big Data [1] was jointly organized by the RSC Special Interest group on Chemical Information and Computer applications (CICAG) [2] and the UK Engineering and Physical Sciences Research Council Grand Challenge of Dial ...
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A meeting on Big Data [1] was jointly organized by the RSC Special Interest group on Chemical Information and Computer applications (CICAG) [2] and the UK Engineering and Physical Sciences Research Council Grand Challenge of Dial a Molecule (DaM) [3] and held 22 April 2015 at the Royal Society of Chemistry, Burlington House, London, UK.
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The world surrounding us is ever changing. It is one of the majorchallenges of modern science to pro-vide a rationale for the kinetics gov-erning processes in areas extendingfrom solid-state physics via chemistryto biology and eve...
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The world surrounding us is ever changing. It is one of the majorchallenges of modern science to pro-vide a rationale for the kinetics gov-erning processes in areas extendingfrom solid-state physics via chemistryto biology and everyday technology.More than fifty scientists from fourcontinents convened from September27 to 28, 2007 in Gottingen to discussthe use of neutrons to address thischallenge. The symposium was orga-nized jointly by the University ofGottingen, the European Neutron andMuon Integrated Infrastructure Initia-tive (NMI3), and the Oak RidgeNational Laboratory.
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In this note, we show that the norm of an nxn random jointly exchangeable matrix with zero diagonal can be estimated in terms of the norm of its [n/2] x [n/2] submatrix located in the top right corner. As a consequence, we prove a...
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In this note, we show that the norm of an nxn random jointly exchangeable matrix with zero diagonal can be estimated in terms of the norm of its [n/2] x [n/2] submatrix located in the top right corner. As a consequence, we prove a relation between the second largest singular values of a random matrix with constant row and column sums and its top right [n/2] x [n/2] submatrix. The result has an application to estimating the spectral gap of random undirected d-regular graphs in terms of the second singular value of directed random graphs with predefined degree sequences.
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This paper presents a numerical investigation of the mechanical behaviour of segmental linings owing to the existence of voids in the composite lining. The composite lining was formed by mining outside and shield tunnelling inside...
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This paper presents a numerical investigation of the mechanical behaviour of segmental linings owing to the existence of voids in the composite lining. The composite lining was formed by mining outside and shield tunnelling inside with backfill in between. Finite element method was conducted to analyse the axial forces and bending moment for voids of different diameters at different positions. The results show that the axial forces in the transverse section increase near the crown and then invert and decrease on the left and right sides with an increase in the void centre angle (β) measured from the vertical axis. The increase in void diameter (d?收起
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The purpose of this paper is to develop inequalities for Kronecker products and Hadamard products ofpositive definite matrices. A number of inequalities involving powers, Kronecker powers, and Hadamard powers of linearcombination ...
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The purpose of this paper is to develop inequalities for Kronecker products and Hadamard products ofpositive definite matrices. A number of inequalities involving powers, Kronecker powers, and Hadamard powers of linearcombination of matrices are presented. In particular, Holder inequalities and arithmetic mean-geometric mean inequalitiesfor Kronecker products and Hadamard products are obtained as special cases.
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