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Parallelization and I/O performance optimization of a global nonhydrostatic dynamical core using MPI
The Global ‐ Regional Integrated forecast SysTem (GRIST) is the next-
generation weather and climate integrated model dynamic framework developed by
Chinese Academy of Meteorological Sciences. In this paper, we present several changes
made to the global nonhydrostatic dynamical (GND) core, which is part of the ongoing
prototype of GRIST. The changes leveraging MPI and PnetCDF techniques were targeted
at the parallelization and performance optimization to the original serial GND core.
Meanwhile, some sophisticated data structures and interfaces were designed to adjust
flexibly the size of boundary and halo domains according to the variable accuracy in
parallel context. In addition, the I/O performance of PnetCDF decreases as the number of
MPI processes increases in our experimental environment. Especially when the number
exceeds 6000, it caused system-wide outages (SWO). Thus, a grouping solution was
proposed to overcome that issue. Several experiments were carried out on the
supercomputing platform based on Intel x86 CPUs in the National Supercomputing
Center in Wuxi. The results demonstrated that the parallel GND core based on grouping
solution achieves good strong scalability and improves the performance significantly, as
well as avoiding the SWOs
Multi-decadal trends in global terrestrial evapotranspiration and its components
Evapotranspiration (ET) is the process by which liquid water becomes water vapor and energetically this accounts for much of incoming solar radiation. If this ET did not occur temperatures would be higher, so understanding ET trends is crucial to predict future temperatures. Recent studies have reported prolonged declines in ET in recent decades, although these declines may relate to climate variability. Here, we used a well-validated diagnostic model to estimate daily ET during 1981–2012, and its three components: transpiration from vegetation (Et), direct evaporation from the soil (Es) and vaporization of intercepted rainfall from vegetation (Ei). During this period, ET over land has increased significantly (p < 0.01), caused by increases in Et and Ei, which are partially counteracted by Es decreasing. These contrasting trends are primarily driven by increases in vegetation leaf area index, dominated by greening. The overall increase in Et over land is about twofold of the decrease in Es. These opposing trends are not simulated by most Coupled Model Intercomparison Project phase 5 (CMIP5) models, and highlight the importance of realistically representing vegetation changes in earth system models for predicting future changes in the energy and water cycle
Semiconducting nonperovskite ferroelectric oxynitride designed ab initio
Recent discovery of HfO2-based and nitride-based ferroelectrics that are
compatible to the semiconductor manufacturing process have revitalized the
field of ferroelectric-based nanoelectronics. Guided by a simple design
principle of charge compensation and density functional theory calculations, we
discover HfO2-like mixed-anion materials, TaON and NbON, can crystallize in the
polar Pca21 phase with a strong thermodynamic driving force to adopt anion
ordering spontaneously. Both oxynitrides possess large remnant polarization,
low switching barriers, and unconventional negative piezoelectric effect,
making them promising piezoelectrics and ferroelectrics. Distinct from HfO2
that has a wide band gap, both TaON and NbON can absorb visible light and have
high charge carrier mobilities, suitable for ferroelectric photovoltaic and
photocatalytic applications. This new class of multifunctional nonperovskite
oxynitride containing economical and environmentally benign elements offer a
platform to design and optimize high-performing ferroelectric semiconductors
for integrated systems
Binding affinity-based intracellular drug detection enabled by a unimolecular cucurbit[7]uril-dye conjugate
Label-free fluorescence-based chemosensing has been increasingly brought into focus due to its simplicity and high sensitivity for intracellular monitoring of molecules. Currently used methods, such as conventional indicator displacement assays (IDAs), pose limitations related to dissociation upon dilution, random diffusion of the released indicators, and high sensitivity to interference by agents from the ambient cellular environment (e.g., salts, enzymes, and proteins). Herein we report a potentially widely applicable strategy to overcome the limitations of conventional IDAs by employing a macrocyclic cucurbit[7]uril (CB7) host covalently coupled to a nitrobenzoxadiazole (NBD) fluorescent dye (CB7-NBD conjugate). As a proof of concept, we demonstrated that the CB7-NBD unimolecular conjugate responded to various target analytes even in the complex live cell system. Moreover, the sensing system was compatible with fluorescence imaging, fluorescence-assisted cell sorting (FACS), and fluorescence spectrometry with a microplate reader. These experiments demonstrated an application of covalently bound unimolecular CB7-NBD conjugate as a sensor for detecting diverse analytes in the intracellular compartment of live cells
Intrinsic ferroelectric switching in two-dimension -InSe
Two-dimensional (2D) ferroelectric semiconductors present opportunities for
integrating ferroelectrics into high-density ultrathin nanoelectronics. Among
the few synthesized 2D ferroelectrics, -InSe, known for its
electrically addressable vertical polarization has attracted significant
interest. However, the understanding of many fundamental characteristics of
this material, such as the existence of spontaneous in-plane polarization and
switching mechanisms, remains controversial, marked by conflicting experimental
and theoretical results. Here, our combined experimental characterizations with
piezoresponse force microscope and symmetry analysis conclusively dismiss
previous claims of in-plane ferroelectricity in -InSe. The
processes of vertical polarization switching in monolayer -InSe
are explored with deep-learning-assisted large-scale molecular dynamics
simulations, revealing atomistic mechanisms fundamentally different from those
of bulk ferroelectrics. Despite lacking in-plane effective polarization, 1D
domain walls can be moved by both out-of-plane and in-plane fields, exhibiting
unusual avalanche dynamics characterized by abrupt, intermittent moving
patterns. The propagating velocity at various temperatures, field orientations,
and strengths can be statistically described with a universal creep equation,
featuring a dynamical exponent of 2 that is distinct from all known values for
elastic interfaces moving in disordered media. This work rectifies a long-held
misunderstanding regarding the in-plane ferroelectricity of
-InSe, and the quantitative characterizations of domain wall
velocity will hold broad implications for both the fundamental understanding
and technological applications of 2D ferroelectrics.Comment: 30 pages, 6 figure
A Modular Framework of Distributed Hydrological Modeling System: Hydroinformatic Modeling System, HIMS
Distributed hydrological models have been shown high light on because of the spatial variability of hydrological processes. On the other hand, the complexity of the hydrological processes, the multi-purposes of hydrological modeling and the availability of observed data have made it difficult to bring forward a hydrological model system for general use. It is always confused and time consumed to find a model of most fit to practical application because of the variety types of hydrological models. In this paper, the framework of a modular based distributed hydrological modeling system has been discussed. The system was so called Hydroinformatic Modeling System (HIMS), include hydroinformatic management system, data pre- and post-processing system, and hydrological model & function library. For the management and processing of spatial information, basic GIS functions have been integrated into system on the basis of SUPERMAP, which is component based GIS software. The hydrological function library (HFL), which represents different processes of hydrological cycle, was the core of the entire system. Distributed hydrological models of different scale were all established on the HFL. The HIMS has been applied to hydrological research in the Yellow River Basin and has reached to some success. However, since it is still in its trial version, much more work need to be done to improve it
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