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Transformation of long-period stacking ordered structures in Mg-Gd-Y-Zn alloys upon synergistic characterization of first-principles calculation and experiment and its effects on mechanical properties

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Journal of Magnesium and Alloys 2024年第5期12卷 1867-1879页

作者： Mingyu li Guangzong Zhang Siqi Yin Changfeng Wang Ying Fu Chenyang Gu Renguo Guan School of Materials Science and Engineering Northeastern UniversityShenyang 110819China Key Laboratory of Near-Net Forming of light Metals of liaoning Province Dalian Jiaotong UniversityDalian 116028China Engineering Research Center of Continuous Extrusion Ministry of EducationDalian Jiaotong UniversityDalian 116028China Songshan Lake Materials Laboratory Dongguan 523808China

Based on experiments and first-principles calculations,the microstructures and mechanical properties of as-cast and solution treated Mg-10Gd-4Y-xZn-0.6Zr(x=0,1,2,wt.%)alloys are *** transformation process of long-period stacking ordered(LPSO)structure during solidification and heat treatment and its effect on the mechanical properties of experimental alloys are *** reveal that the stacking faults and 18R LPSO phases appear in the as-cast Mg-10Gd-4Y-1Zn-0.6Zr and Mg-10Gd-4Y-2Zn-0.6Zr alloys,*** solution treatment,the stacking faults and 18R LPSO phase transform into 14H LPSO *** Enthalpies of formation and reaction energy of 14H and 18R LPSO are calculated based on *** show that the alloying ability of 18R is stronger than that of *** reaction energies show that the 14H LPSO phase is more stable than the 18R *** elastic properties of the 14H and 18R LPSO phases are also evaluated by first-principles calculations,and the results are in good agreement with the experimental *** precipitation of LPSO phase improves the tensile strength,yield strength and elongation of the *** solution treatment,the Mg-10Gd-4Y-2Zn-0.6Zr alloy has the best mechanical properties,and its ultimate tensile strength and yield strength are 278.7 MPa and 196.4 MPa,*** elongation of Mg-10Gd-4Y-2Zn-0.6Zr reaches 15.1,which is higher than that of Mg-10Gd-4Y0.6Zr *** improving mechanism of elastic modulus by the LPSO phases and the influence on the alloy mechanical properties are also analyzed.

关键词： Mg-Gd-Y-Zn alloys Long-period stacking ordered First-principles calculations Enthalpies Mechanical properties

The pseudospectrum and spectrum (in)stability of quantum corrected Schwarzschild black hole

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Science China(Physics,Mechanics & Astronomy) 2024年第10期Mechanics & Astronomy) .卷 59-79页

作者： li-Ming Cao Jia-Ning Chen liang-Bi Wu libo Xie Yu-Sen Zhou Peng Huanwu Center for Fundamental Theory Interdisciplinary Center for Theoretical Study and Department of Modern Physics University of Science and Technology of China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCAS

In this study, we investigate the pseudospectrum and spectrum(in)stability of quantum corrected Schwarzschild black ***, we use the hyperboloidal framework to cast the quasinormal mode(QNM) problem into an eigenvalue problem associated with a non-selfadjoint operator, and then the spectrum and pseudospectrum are depicted. Besides, the invariant subspace method is exploited to improve the computational efficiency for pseudospectrum. The investigation into the spectrum(in)stability entails two main aspects. On the one hand, we calculate the spectra of the quantum corrected black hole, then by the means of the migration ratio, the impact of the quantum correction effect on the Schwarzschild black hole has been *** results indicate that the so-called “migration ratio instability” will occur for small black holes with small angular momentum number l. In the eikonal limit, the migration ratios remain the same for each overtone. On the other hand, we study the spectrum(in)stability of the quantum corrected black hole by directly adding some particular perturbations into the effective potential,where perturbations are located at the event horizon and null infinity, respectively. There are two interesting observations under the same perturbation energy norm. First, perturbations at infinity are more capable of generating spectrum instability than those at the event horizon. Second, we find that the peak distribution can lead to the instability of QNM spectrum more efficiently than the average distribution.

关键词： quasinormal modes pseudospectrum hyperboloidal coordinate

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Extended light absorption and accelerated charge migration in ultrathin twisted carbon nitride nanoplates for efficient solar hydrogen production

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Science China Chemistry 2024年第7期67卷 2215-2223页

作者： Yanmin Zou Shiyao li Dandan Zheng Jianyong Feng Sibo Wang Yidong Hou Guigang Zhang State Key Laboratory of Photocatalysis on Energy and Environment College of ChemistryFuzhou UniversityFuzhou 350108China College of Environment and Safety Engineering Fuzhou UniversityFuzhou 350108China Collaborative Innovation Center of Advanced Microstructures National Laboratory of Solid State MicrostructuresCollege of Engineering and Applied SciencesNanjing UniversityNanjing 210093China

Polymeric carbon nitride has been widely developed as a promising photocatalyst for solar hydrogen production via photocatalytic water ***,pristine carbon nitride prepared by traditional solid-state polymerization usually encounters issues such as rapid carrier recombination and insufficient absorption of visible light below 460 ***,poly(heptazine imide)with a distinctive nanoplate structure was synthesized in a binary molten salt of NaCl–CaCl_(2).The salt template allows the formation of the thin nanoplate structure,which promotes the charge separation and ***,the intercalation of Ca^(2+)ions between the conjugated layers endows the activation of n–π*electron transition due to the distortion of in-plane heptazine ***,the optimized poly(heptazine imide)nanoplates achieve an apparent quantum efficiency of up to 17.3%at 500 nm for photocatalytic hydrogen production from *** work shares new idea for rational control of the optical absorption and charge carrier dynamics of poly(heptazine imide).

关键词： photocatalysis poly heptazine imide nanoplates ion intercalation hydrogen production

Investigation on Degradation Path of SF_(6)in Packed-bed Plasma:Effect of Plasma-generated Radicals

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1231-1241页

作者： Zhaolun Cui Chang Zhou Amin Jafarzadeh Xiaoxing Zhang Peng Gao licheng li Yanpeng Hao School of Electric Power Engineering South China University of TechnologyGuangzhou 510630China School of Electrical and Electronic Engineering Hubei University of TechnologyWuhan 430068China Research group PLASMANT Department of ChemistryUniversity of AntwerpUniversiteitsplein 1BE-2610 Wilrijk-AntwerpBelgium CSEE

SF_(6)degradation mechanism in non-thermal plasma(NTP)systems is not fully understood due to the formation of a complex physico-chemical reaction network,especially when reactive gases and packing materials are *** this work,we conduct a combined experimental and theoretical study to unravel the SF_(6)degradation path in a-Al_(2)O_(3)packed plasma in the presence of H_(2)O or O_(2).Our experimental results show that both H_(2)O and O_(2)have a synergetic effect with-Al_(2)O_(3)packing on promoting SF_(6)degradation,leading to higher stable gas yields than typical spark or corona discharges.H_(2)O or O_(2)addition promotes SO_(2)or SO_(2)F_(2)selectivity,*** functional theory(DFT)calculations reveal that SO_(2)generation corresponding with the highest activation barrier is the most critical step toward SF_(6)*** like H and O generated from H_(2)O or O_(2)discharge can significantly promote the degradation process via Eley-Rideal mechanism,affecting key reactions of stable product generation,advancing degradation *** results of this work could provide insights on further understanding SF_(6)degradation mechanism especially in packed-bed plasma systems.

关键词： Degradation mechanism packed-bed plasma radicals SF_(6)

Refined acoustic holography via nonlocal metasurfaces

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 113-123页

作者： Shuhuan Xie Hongyu Ma Junmei Cao Fangshuo Mo Qian Cheng Yong li Tong Hao Institute of Acoustics School of Physics Science and EngineeringTongji UniversityShanghai 200092China Center for Spatial Information Science and Sustainable Development Applications Tongji UniversityShanghai 200092China College of Surveying and Geo-Informatics Tongji UniversityShanghai 200092China

Holography can provide the desired wavefront phase and/or amplitude for imaging,particle manipulation,bacteria trapping,and cell patterning in optics and ***,previous work on acoustic holography is mostly based on local design optimization,either using active control of the sound source or relying on the structural design to provide the desired *** precise control over the acoustic field remains a significant ***,we realize refined single-plane symmetric binary amplitude,asymmetric intensity gradient amplitude,and bi-objective hologram through the non-local holographic imaging theory that considers the acoustic coupling of structural units in *** taking into account the self-radiation and mutual radiation between many small units on a plate of well-designed thickness,as well as the transmission through the plate's apertures,we can effectively regulate the sound field behind the *** demonstrate the effectiveness of our approach through numerical simulations and experiments,showcasing a circle,a black hole,and a bi-objective with a circle and a square ***,the acoustic black hole hologram precisely reconstructs the intensity gradient distribution at two bright *** non-local holographic imaging theory is valuable for the fine-intensity regulation of the sound field and is expected to be applied in ultrasound diagnosis and treatment,medical imaging,and other fields.

关键词： acoustic holograms non-local interactions fine intensity modulation acoustic metasurfaces

Observation of an upward lightning flash with 21 upward positive leaders initiated from different wind turbines in wind farm

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High Voltage 2024年第1期9卷 163-171页

作者： li Cai Yifeng Ke Wenchao Fan Ruisheng Yan Mi Zhou Jianguo Wang Yadong Fan Engineering Research Center of Ministry of Education for lightning Protection and Grounding Technology School of Electrical Engineering and AutomationWuhan UniversityWuhanChina

As the wind turbine height increases,the probability of multiple upward leaders flashes within the wind farm *** this study,an upward lightning flash containing 21 upward positive leaders(UPLs)initiated from different wind turbines in Zhangbei Wind Farm was *** average speed of the UPLs was 1.2×10^(5) m/s,which mostly decreased to zero before reaching the cloud *** four UPLs developed to cloud height,with prolonged periods of bright light on three of them and with a minimum duration of 126 ms.A total of nine return strokes occurred on the other two dissipated leader channels,and the numbers of strokes on the two channels was six and three,*** average interstroke interval for the return strokes was 10.5 *** of these nine return strokes had peak currents smaller than 10 *** high-speed video frames confirmed that competition does exist between the UPLs,and the range of shielding effects increases as the height of the ULs *** effect of fan rotation on the initiation of upward leaders and the shielding effect between the wind turbines and upward leaders are discussed.

关键词： flash return initiated

An Experimental Analysis of Gas-liquid Flow Breakdown in a T-Junction

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Fluid Dynamics & Materials Processing 2024年第6期20卷 1381-1392页

作者： lihui Ma Zhuo Han Wei li Guangfeng Qi Ran Cheng Yuanyuan Wang Xiangran Mi Xiaohan Zhang Yunfei li Technical Inspection Center Sinopec Shengli Oilfield CompanyDongying257000China New Energy Development Center Sinopec Shengli Oilfield CompanyDongying257000China China National Oil and Gas Exploration and Development Company Ltd.Beijing100034China

When a gas-liquid two-phase flow(GLTPF)enters a parallel separator through a T-junction,it generally splits *** phenomenon can seriously affect the operation efficiency and safety of the equipment located *** order to investigate these aspects and,more specifically,the so-called bias phenomenon(all gas and liquid flowing to one pipe,while the other pipe is a liquid column that fluctuates up and down),laboratory experiments were carried out by using a T-junction connected to two parallel vertical ***,a GLTPF prediction model based on the principle of minimum potential energy was *** research results indicate that this model can accurately predict the GLTPF state in parallel *** boundary of the slug flow and the churn flow in the opposite pipe can be ***,according to the results,the pressure drop curves of the two-phase flow in the parallel risers are basically the same when there is no bias phenomenon,but the pressure drop in the parallel riser displays a large deviation when there is a slug flow-churn *** when the parallel riser is in a state of asymmetric flow and one of the risers produces churn flow,the two-phase flow is prone to produce the bias phenomenon.

关键词： Two-phase flow T-junction split model entrance effect mechanism model improved model

2023 Guideline for the management of hypertension in the elderly population in China

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Journal of Geriatric Cardiology 2024年第6期21卷 589-630页

作者： Hypertension Branch of Chinese Geriatrics Society,Beijing Hypertension Association,National Clinical Research Center of the Geriatric Diseases Qi HUA li FAN Zeng-Wu WANG Jing li 不详 Xuanwu Hospital Capital Medical UniversityBeijingChina Chinese PLA General Hospital BeijingChina Fuwai Hospital Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina

Preamble Hypertension is one of the most common chronic diseases and the primary risk factor for stroke,myocardial infarction and even cardiovascular *** than half of the elderly population has high blood *** people are a unique group,and strategies for the prevention,diagnosis,evaluation,and treatment of hypertension in elderly individuals differ significantly from those in the general population.

关键词： hypertension prevention diagnosis

Prioritization of risk genes in colorectal cancer by integrative analysis of multi-omics data and gene networks

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Science China(life Sciences) 2024年第1期67卷 132-148页

作者： Ming Zhang Xiaoyang Wang Nan Yang Xu Zhu Zequn Lu Yimin Cai Bin li Ying Zhu Xiangpan li Yongchang Wei Shaokai Zhang Jianbo Tian Xiaoping Miao Department of Epidemiology and Biostatistics School of Public HealthDepartment of Gastrointestinal OncologyZhongnan Hospital of Wuhan UniversityDepartment of Radiation OncologyRenmin Hospital of Wuhan UniversityTaiKang Center for Life and Medical SciencesWuhan UniversityWuhan 430071China Research Center of Public Health Renmin hospital of Wuhan UniversityWuhan UniversityWuhan 430060China Department of Cancer Epidemiology The Affiliated Cancer Hospital of Zhengzhou University&Henan Cancer HospitalHenan Engineering Research Center of Cancer Prevention and ControlHenan International Joint Laboratory of Cancer PreventionZhengzhou 450008China Department of Gastrointestinal Surgery Renmin Hospital of Wuhan UniversityWuhan 430060China Department of Radiation Oncology Renmin Hospital of Wuhan UniversityWuhan 430060China Department of Gastrointestinal Oncology Hubei Cancer Clinical Study CenterZhongnan Hospital of Wuhan UniversityWuhan 430062China Department of Epidemiology and Biostatistics School of Public HealthTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430073China Jiangsu Collaborative Innovation Center for Cancer Personalized Medicine Nanjing Medical UniversityNanjing 211166China

Genome-wide association studies(GWASs)have identified over 140 colorectal cancer(CRC)-associated loci;however,target genes at the majority of loci and underlying molecular mechanisms are poorly ***,we utilized a Bayesian approach,integrative risk gene selector(iRIGS),to prioritize risk genes at CRC GWAS loci by integrating multi-omics *** a result,a total of 105 high-confidence risk genes(HRGs)were identified,which exhibited strong gene dependencies for CRC and enrichment in the biological processes implicated in *** the 105 HRGs,CEBPB,located at the 20q13.13 locus,acted as a transcription factor playing critical roles in *** subsequent assays indicated the tumor promoter function of CEBPB that facilitated CRC cell proliferation by regulating multiple oncogenic pathways such as MAPK,PI3K-Akt,and Ras ***,by integrating a fine-mapping analysis and three independent case-control studies in Chinese populations consisting of 8,039 cases and 12,775 controls,we elucidated that rs1810503,a putative functional variant regulating CEBPB,was associated with CRC risk(OR=0.90,95%CI=0.86–0.93,P=1.07×10^(−7)).The association between rs1810503 and CRC risk was further validated in three additional multi-ancestry populations consisting of 24,254 cases and 58,741 ***,the rs1810503 A to T allele change weakened the enhancer activity in an allele-specific manner to decrease CEBPB expression via longrange promoter-enhancer interactions,mediated by the transcription factor,REST,and thus decreased CRC *** summary,our study provides a genetic resource and a generalizable strategy for CRC etiology investigation,and highlights the biological implications of CEBPB in CRC tumorigenesis,shedding new light on the etiology of CRC.

关键词： susceptibility genes gene screening models multi-omics GWAS CEBPB long-range promoter-enhancer interactions