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1,069 results on '"Guo, Junming"'

2. ScaleLat: A chemical structure matching algorithm for mapping atomic structure of multi-phase system and high entropy alloys

Author

Li, Nan, Guo, Junming, Li, Sateng, Liu, Haoliang, Li, Qianwu, Shi, Fangjie, Li, Yefei, and Xiao, Bing

Subjects
Condensed Matter - Materials Science, Physics - Computational Physics
Abstract

ScaleLat (Scale Lattice) is a computer program written in C for performing the atomic structure analysis of multi-phase system or high entropy alloys (HEAs). The program implements an atomic cluster extraction algorithm to obtain all independent and symmetry-reduced characteristic chemical structures for the complex atomic configurations which are usually obtained from molecular dynamics or kinetic Monte-Carlo simulations for supercell containing more than 104 atoms. ScaleLat employes an efficient and unique chemical structure matching algorithm to map all extracted atomic clusters from a large supercell (>10^4 atoms) to a representative small one (~ 10^3 or less), providing the possibility to directly use the highly accurate quantum mechanical methods to study the electronic, magnetic, and mechanical properties of multi-component alloys with complex microstructures. We demonstrate the capability of ScaleLat code by conducting both the atomic structure analysis and chemical structure matching procedure for Fe-12.8 at.% Cr binary alloy and equiatomic CrFeCoNiCu high entropy alloy, and by successfully obtaining the representatively supercells containing 10^2~10^3 atoms of the two alloys. Overall, ScaleLat program provides a universal platform to efficiently project all essential chemical structures of large complex atomic structures to a relatively easy-handling small supercell for quantum mechanical calculations of various user interested properties.

Published
2023

4. Modulating above-room-temperature magnetism in Ga-implanted Fe5GeTe2 van der Waals magnets

Author

Yuan, Yanan, Liu, Daxiang, Yu, Jingjing, Zhang, Guanhua, Chen, Xiang, Liu, Ruiqi, Wang, Siyu, Pei, Fangfang, Wei, Long, Li, Zhi, Guo, Junming, Wang, Shouguo, Liao, Zhaoliang, Yan, Wensheng, Qiu, Ziqiang, Yang, Mengmeng, and Li, Qian

Subjects
Quantum Physics, Physical Sciences, Condensed Matter Physics, Electrical and Electronic Engineering, Materials Engineering, Mechanical Engineering, Materials engineering, Nanotechnology, Condensed matter physics
Abstract

The creation of van der Waals (vdW) ferromagnets with tunable Curie temperature (TC) and magnetic anisotropy is essential in developing vdW magnet-based devices. Here, we report an effective and reliable method for modulating the magnetic properties of vdW Fe5GeTe2 by site-specific Ga+ implantation. In this study, we report an easy axis in the ab-plane for bulk Fe5GeTe2 (TC = 310 K) and an axis out of the plane for thin Fe5GeTe2 flakes (TC = 290 K). Combining element-resolved photoemission electron microscopy and spatially resolved magneto-optic Kerr microscopy, we find that the implantation of a tiny amount of 10−3 Ga+·Å−3 in Fe5GeTe2 greatly enhances the TC from 290 to 360 K and switches the magnetic easy axis from the out-of-plane c axis to the ab-plane. The room-temperature x-ray magnetic circular dichroism signal is enhanced from 0% to 9% at an implantation level of 10−2 Ga+·Å−3. These results provide new opportunities for tailoring the magnetic properties of vdW materials beyond room temperature.

Published
2023

5. Roland-Morris Disability Questionnaire Measurement Performance Evidence in Chinese Patients with Low Back Pain: a Systematic Review Based on COSMIN Guidelines

Author

GAO Yixuan, WANG Xiyou, CHEN Qianji, YANG Xiaoming, GUO Junming, ZI Yilu, WENG Zhiwen, MA Jingyi, ZHANG Naiwen, LIU Eryang, SHAO Hui, SUN Yanan, YU Changhe

Subjects
low back pain, roland-morris disability questionnaire, cosmin, validity, reliability, responsiveness, Medicine
Abstract

Background The global prevalence of low back pain is gradually increasing, and it is the main cause of disability, sick leave, and unemployment, posing a heavy burden on individuals and society. Assessing the degree of disability in patients with chronic low back pain is crucial for evaluating the efficacy of clinical interventions and clinical epidemiology. The Roland-Morris Disability Questionnaire (RMDQ) is currently the main tool for evaluating disability in patients with low back pain, but the applicability of its measurement performance in the Chinese population remains unclear. Objective To evaluate the applicability of RMDQ in the Chinese population with low back pain and provide evidence for clinical practice and research application. Methods CNKI, Wanfang Data Knowledge Service Platform, SinoMed, PubMed, Embase and Web of Science were searched from inception to 2023-10-01, to establish a literature base for the performance of the low back pain scale, and then select research on the measurement performance of RMDQ from it. The measurement performance of the RMDQ scale was evaluated according to the COSMIN system evaluation guidelines, and the evidence evaluation level was used to grade the evidence. Results A total of six RMDQ documents were included, with insufficient methodological quality for RMDQ content validity and adequate measurement performance. The quality of internal consistency methodology was very good with uncertainty and measurement performance was adequate; the methodological quality of retesting was uncertain, and the measurement performance was sufficient; the methodological quality of measurement error was uncertain, and the measurement performance was sufficient; the methodological quality of criterion validity was uncertain, and the measurement performance was insufficient; hypothesis testing methodological quality was very good with uncertain, and the measurement performance was sufficient and uncertain; the quality of reactivity methodology was very good, with sufficient and insufficient, while the measurement performance was sufficient with insufficient. According to the GRADE evidence quality rating results, there is low quality evidence to prove uncertainty in content validity, and moderate quality evidence to prove sufficient retesting reliability and internal consistency; there is sufficient evidence of low quality to prove the measurement error and reactivity. There is very low quality evidence of insufficient calibration validity when using the Oswestry Dysfunction Index (ODI) and the Visual Analog Scale (VAS) as calibrators; hypothesis testing had moderate quality evidence of uncertainty. Conclusion The methodological quality of the RMDQ scale is not high, with acceptable measurement performanceand low quality of evidence, and needs to be used cautiously in clinical practice or trials of low back pain in China. Although there is sufficient evidence of moderate quality to prove the reliability and internal consistency of retesting, the research content and methods are not standardized. In future research, attention should be paid to standardization to more accurately assess its applicability in the Chinese population.

Published
2024
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