43 research outputs found

    Spin and Valley Polarized Multiple Fermi Surfaces of {\alpha}-RuCl3_3/Bilayer Graphene Heterostructure

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    We report the transport properties of α{\alpha}-RuCl3_3/bilayer graphene heterostructures, where carrier doping is induced by a work function difference, resulting in distinct electron and hole populations in α{\alpha}-RuCl3 and bilayer graphene, respectively. Through a comprehensive analysis of multi-channel transport signatures, including Hall measurements and quantum oscillation, we unveil significant band modifications within the system. In particular, we observe the emergence of spin and valley polarized multiple hole-type Fermi pockets, originating from the spin-selective band hybridization between α{\alpha}-RuCl3_3 and bilayer graphene, breaking the spin degree of freedom. Unlike α{\alpha}-RuCl3_3 /monolayer graphene system, the presence of different hybridization strengths between α{\alpha}-RuCl3_3 and the top and bottom graphene layers leads to an asymmetric behavior of the two layers, confirmed by effective mass experiments, resulting in the manifestation of valley-polarized Fermi pockets. These compelling findings establish α{\alpha}-RuCl3_3 proximitized to bilayer graphene as an outstanding platform for engineering its unique low-energy band structure.Comment: accepted to AP

    Enhanced Electron Correlation and Significantly Suppressed Thermal Conductivity in Dirac Nodal-Line Metal Nanowires by Chemical Doping

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    Enhancing electron correlation in a weakly interacting topological system has great potential to promote correlated topological states of matter with extraordinary quantum properties. Here, the enhancement of electron correlation in a prototypical topological metal, namely iridium dioxide (IrO2), via doping with 3d transition metal vanadium is demonstrated. Single-crystalline vanadium-doped IrO2 nanowires are synthesized through chemical vapor deposition where the nanowire yield and morphology are improved by creating rough surfaces on substrates. Vanadium doping leads to a dramatic decrease in Raman intensity without notable peak broadening, signifying the enhancement of electron correlation. The enhanced electron correlation is further evidenced by transport studies where the electrical resistivity is greatly increased and follows an unusual √ T dependence on the temperature (T). The lattice thermal conductivity is suppressed by an order of magnitude via doping even at room temperature where phonon-impurity scattering becomes less important. Density functional theory calculations suggest that the remarkable reduction of thermal conductivity arises from the complex phonon dispersion and reduced energy gap between phonon branches, which greatly enhances phase space for phonon–phonon Umklapp scattering. This work demonstrates a unique system combining 3d and 5d transition metals in isostructural materials to enrich the system with various types of interactions

    Genome structure and diversity among Cynanchum wilfordii accessions

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    Abstract Background Cynanchum wilfordii (Cw) and Cynanchum auriculatum (Ca) have long been used in traditional medicine and as functional food in Korea and China, respectively. They have diverse medicinal functions, and many studies have been conducted, including pharmaceutical efficiency and metabolites. Especially, Cw is regarded as the most famous medicinal herb in Korea due to its menopausal symptoms relieving effect. Despite the high demand for Cw in the market, both species are cultivated using wild resources with rare genomic information. Results We collected 160 Cw germplasm from local areas of Korea and analyzed their morphological diversity. Five Cw and one Ca of them, which were morphologically diverse, were sequenced, and nuclear ribosomal DNA (nrDNA) and complete plastid genome (plastome) sequences were assembled and annotated. We investigated the genomic characteristics of Cw as well as the genetic diversity of plastomes and nrDNA of Cw and Ca. The Cw haploid nuclear genome was approximately 178 Mbp. Karyotyping revealed the juxtaposition of 45S and 5S nrDNA on one of 11 chromosomes. Plastome sequences revealed 1226 interspecies polymorphisms and 11 Cw intraspecies polymorphisms. The 160 Cw accessions were grouped into 21 haplotypes based on seven plastome markers and into 108 haplotypes based on seven nuclear markers. Nuclear genotypes did not coincide with plastome haplotypes that reflect the frequent natural outcrossing events. Conclusions Cw germplasm had a huge morphological diversity, and their wide range of genetic diversity was revealed through the investigation with 14 molecular markers. The morphological and genomic diversity, chromosome structure, and genome size provide fundamental genomic information for breeding of undomesticated Cw plants

    2023 Korean Endocrine Society Consensus Guidelines for the Diagnosis and Management of Primary Aldosteronism

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    Primary aldosteronism (PA) is a common, yet underdiagnosed cause of secondary hypertension. It is characterized by an overproduction of aldosterone, leading to hypertension and/or hypokalemia. Despite affecting between 5.9% and 34% of patients with hypertension, PA is frequently missed due to a lack of clinical awareness and systematic screening, which can result in significant cardiovascular complications. To address this, medical societies have developed clinical practice guidelines to improve the management of hypertension and PA. The Korean Endocrine Society, drawing on a wealth of research, has formulated new guidelines for PA. A task force has been established to prepare PA guidelines, which encompass epidemiology, pathophysiology, clinical presentation, diagnosis, treatment, and follow-up care. The Korean clinical guidelines for PA aim to deliver an evidence-based protocol for PA diagnosis, treatment, and patient monitoring. These guidelines are anticipated to ease the burden of this potentially curable condition

    Shape Design of the Surface Mounted Permanent Magnet in a Synchronous Machine

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    Enhancing Data Transfer Performance Utilizing a DTN between Cloud Service Providers

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    The rapid transfer of massive data in the cloud environment is required to prepare for unexpected situations like disaster recovery. With regard to this requirement, we propose a new approach to transferring cloud virtual machine images rapidly in the cloud environment utilizing dedicated Data Transfer Nodes (DTNs). The overall procedure is composed of local/remote copy processes and a DTN-to-DTN transfer process. These processes are coordinated and executed based on a fork system call in the proposed algorithm. In addition, we especially focus on the local copy process between a cloud controller and DTNs and improve data transfer performance through the well-tuned mount techniques in Network File System (NFS)-based connections. Several experiments have been performed considering the combination of synchronous/asynchronous modes and the network buffer size. We show the results of throughput in all the experiment cases and compare them. Consequently, the best throughput in write operations has been obtained in the case of an NFS server in a DTN and an NFS client in a cloud controller running entirely in the asynchronous mode

    The Performance Enhancement of PMOSFETs and Inverter Chains at Low Temperature and Low Voltage by Removing Plasma-Damaged Layers

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    In this work we report on the improvement in cold temperature characteristics of PMOSFETs and inverter circuits by removing the plasma-damaged layer of the source/drain contacts. We removed the plasma-induced damage on the Si using a simple in situ Si soft treatment technique. We found by transmission electron microscope (TEM) analysis that the damaged amorphous layer reduced from 52 Å to 42 Å and 35 Å with a treatment time of 10 and 20 s, respectively. As a result, the resistances of both the n+ and p+ contacts decreased for all contact sizes and the standard deviations at the cold temperature were suppressed by 45%. At −25 °C, the saturation current of the PMOSFET increased by 3% and the propagation delay time (tPD) decreased by 2%. The tPD increases by 19.3% when the temperature decreases from 85 °C to −25 °C, and the operating voltage decreases from 1.2 V to 0.95 V at the same time. However, this increase can be reduced to 17% by applying the soft treatment for 10 s. This simple and short time process will be considered essential for both mobile applications and automotive applications of dynamic random access memory (DRAM) devices requiring a low-voltage and low-temperature operation
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