67 research outputs found
Finite-temperature violation of the anomalous transverse Wiedemann-Franz law
The Wiedemann-Franz (WF) law links the ratio of electronic charge and heat
conductivity to fundamental constants. It has been tested in numerous solids,
but the extent of its relevance to the anomalous transverse transport, which
represents the topological nature of the wave function, remains an open
question. Here we present a study of anomalous transverse response in the
noncollinear antiferromagnet MnGe extended from room temperature down to
sub-Kelvin temperature and find that the anomalous Lorenz ratio remains close
to the Sommerfeld value up to 100 K, but not above. The finite-temperature
violation of the WF correlation is caused by a mismatch between the thermal and
electrical summations of the Berry curvature, rather than the inelastic
scattering as observed in ordinary metals. This interpretation is backed by our
theoretical calculations, which reveals a competition between the temperature
and the Berry curvature distribution. The accuracy of the experiment is
supported by the verification of the Bridgman relation between the anomalous
Ettingshausen and Nernst effects. Our results identify the anomalous Lorenz
ratio as an extremely sensitive probe of Berry spectrum near the chemical
potential.Comment: 9 pages,6 figures, Supplemental Material include
Study on AADDS Plunger Pump Driving Bearing Properties
The Auto Anti-Deviation Drilling System (AADDS) is a high-performance, highly automated vertical drilling hydraulic guide control system. This article takes its power extraction device - driving bearing for the study object, analyzed the single-plunger pump's principle, established the mathematical model of hydraulic guide system, applied Matlab/Simulink to simulate the pump outlet flow under different contour curve of the driving bearing. The results show the oval-shaped bearing is of high efficiency under lower drilling speed, and its performance is better than that of original eccentric-shaped and clover-shaped
Improved phase-change characteristics of Zn-doped amorphous Sb₇Te₃ films for high-speed and low-power phase change memory
The superior performance of Zn-doped Sb₇Te₃ films might be favorable for the application in phase change memory. It was found that Zn dopants were able to suppress phase separation and form single stable Sb2Te crystal grain, diminish the grain size, and enhance the amorphous thermal stability of Sb₇Te₃ film. Especially, Zn 30.19(Sb₇Te₃)69.81 film has higher crystallization temperature (∼258 °C), larger crystallization activation energy (∼4.15 eV), better data retention (∼170.6 °C for 10 yr), wider band gap (∼0.73 eV), and higher crystalline resistance. The minimum times for crystallization of Zn 30.19(Sb₇Te₃)69.81 were revealed to be as short as ∼10 ns at a given proper laser power of 70 mW.This work was financially supported by the International
Science & Technology Cooperation Program of China
(Grant No. 2011DFA12040), the National Program on Key
Basic Research Project (973 Program) (Grant No.
2012CB722703), the Natural Science Foundation of China
(Grant Nos. 61008041 and 60978058), the CAS Special
Grant for Postgraduate Research, Innovation and Practice,
the Program for Innovative Research Team of Ningbo city
(Grant No. 2009B21007), and sponsored by K. C. Wong
Magna Fund in Ningbo University
Two types of zero Hall phenomena in few-layer MnBiTe
The van der Waals antiferromagnetic topological insulator MnBiTe
represents a promising platform for exploring the layer-dependent magnetism and
topological states of matter. Despite the realization of several quantized
phenomena, such as the quantum anomalous Hall effect and the axion insulator
state, the recently observed discrepancies between magnetic and transport
properties have aroused controversies concerning the topological nature of
MnBiTe in the ground state. Here, we demonstrate the existence of two
distinct types of zero Hall phenomena in few-layer MnBiTe. In addition
to the robust zero Hall plateau associated with the axion insulator state, an
unexpected zero Hall phenomenon also occurs in some odd-number-septuple layer
devices. Importantly, a statistical survey of the optical contrast in more than
200 MnBiTe reveals that such accidental zero Hall phenomenon arises
from the reduction of effective thickness during fabrication process, a factor
that was rarely noticed in previous studies of 2D materials. Our finding not
only resolves the controversies on the relation between magnetism and anomalous
Hall effect in MnBiTe, but also highlights the critical issues
concerning the fabrication and characterization of devices based on 2D
materials.Comment: 21 pages, 4 figure
Epidemiological and genomic analyses of human isolates of Streptococcus suis between 2005 and 2021 in Shenzhen, China
Streptococcus suis (S. suis) is an important food-borne zoonotic pathogen that causes swine streptococcosis, which threatens human health and brings economic loss to the swine industry. Three-quarters of human S. suis infections are caused by serotype 2. A retrospective analysis of human S. suis cases in Shenzhen, a megacity in China, with high pork consumption, between 2005 and 2021 was conducted to understand its genomic epidemiology, pathogen virulence, and drug resistance characteristics. The epidemiological investigation showed that human cases of S. suis in Shenzhen were mainly associated with people who had been in close contact with raw pork or other swine products. Whole-genome sequence analysis showed that 33 human isolates in Shenzhen were dominated by serotype 2 (75.76%), followed by serotype 14 (24.24%), and the most prevalent sequence types (STs) were ST7 (48.48%) and ST1 (39.40%). ST242 (9.09%) and ST25 (3.03%), which were rarely reported, were also found. Phylogenetic analysis showed that the Shenzhen human isolates had close genetic relatedness to isolates from Guangxi (China), Sichuan (China), and Vietnam. We found a new 82 KB pathogenicity island (PAI) in the serotype 2 isolate that may play a role in sepsis. Similarly, a serotype 14 isolate, containing 78 KB PAI, was isolated from a patient presenting with streptococcal toxic shock syndrome (STSLS) who subsequently died. Multi-drug resistance (MDR) was high in human isolates of S. suis from Shenzhen. Most human isolates were resistant to tetracycline, streptomycin, erythromycin, and clindamycin, and 13 isolates had intermediate resistance to penicillin. In conclusion, swine importation from Guangxi, Sichuan, and Vietnam should be more closely monitored, and the use of antibiotics limited to reduce the potential for antimicrobial resistance (AMR)
Disease Gene Interaction Pathways: A Potential Framework for How Disease Genes Associate by Disease-Risk Modules
BACKGROUND: Disease genes that interact cooperatively play crucial roles in the process of complex diseases, yet how to analyze and represent their associations is still an open problem. Traditional methods have failed to represent direct biological evidences that disease genes associate with each other in the pathogenesis of complex diseases. Molecular networks, assumed as 'a form of biological systems', consist of a set of interacting biological modules (functional modules or pathways) and this notion could provide a promising insight into deciphering this topic. METHODOLOGY/PRINCIPAL FINDINGS: In this paper, we hypothesized that disease genes might associate by virtue of the associations between biological modules in molecular networks. Then we introduced a novel disease gene interaction pathway representation and analysis paradigm, and managed to identify the disease gene interaction pathway for 61 known disease genes of coronary artery disease (CAD), which contained 46 disease-risk modules and 182 interaction relationships. As demonstrated, disease genes associate through prescribed communication protocols of common biological functions and pathways. CONCLUSIONS/SIGNIFICANCE: Our analysis was proved to be coincident with our primary hypothesis that disease genes of complex diseases interact with their neighbors in a cooperative manner, associate with each other through shared biological functions and pathways of disease-risk modules, and finally cause dysfunctions of a series of biological processes in molecular networks. We hope our paradigm could be a promising method to identify disease gene interaction pathways for other types of complex diseases, affording additional clues in the pathogenesis of complex diseases
Domestication of rice has reduced the occurrence of transposable elements within gene coding regions
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