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Discovery of new MAX-phase-like layered ternary carbide V_(8)P_(6)C:Crystal structure,thermal expansion,and elastic properties

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Journal of Materials Science & Technology 2024年第7期174卷 55-62页

作者： H.X.Chen L.Sheng Z.L.Zhang X.C.Wen D.L.yang X.y.ye P.Q.Dai School of Materials Science and Engineering Fujian University of TechnologyFuzhou 350118China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of ScienceBeijing 100049China Fujian Provincial Key Laboratory of Advanced Materials Processing and Application Fuzhou 350118China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

Due to the laminated structure,MAX phases and MAX-phase-like compounds possess outstanding dam-age tolerance capability with good thermal/electrical conductivity and other charming functional prop-erties,showing a bright future for structural-functional ***,a new MAX-phase-like ternary car-bide V_(8)P_(6)C with layered characteristics was *** to the alternate stacking of hexagonal-arranged M/A/X atom layers in MAX phases,V_(8)P_(6)C has a layered structure formed by a repeated stacking of the slabs consisting of V_(6)C-octahedrons and VP 6-distorted-octahedrons in three-atomic layers *** thermal expansion anisotropy was revealed,with the thermal expansion coefficients(TECs)along a-axis,c-axis,and the average value,equal toα_(a)=8.55(5)μK^(−1),α_(c)=10.23(5)μK^(−1),andα_(L)=9.14(5)μK^(−1),*** dilation along the c-axis was mainly dominated by out-plane V-P bonds be-tween layered *** to the pressure-dependent lattice parameters,the polycrystalline bulk modulus(B_(0)=185(9)GPa)and high compressibility anisotropy factor(B_(a)/B_(c)=1.64)was ***-while,the second-order elastic constants were calculated,and the elastic moduli,E=303 GPa,B=198 GPa,G=122 GPa,andν=0.246,were *** the weak connection between layer slabs by out-plane V1-P bond was revealed by the bond stiffness model,with a bond stiffness close to the M-A bond in MAX ***,good damage tolerance capability was predicted according to Paugh’s ratio(G/B=0.616)and Cauchy pressure(P_(a)=0 GPa,P_(c)=-7.5 GPa),even better than those of typical MAX *** discovery of V_(8)P_(6)C provides a new member of MAX-phase-like damage-tolerant ceramic with relatively low density,moderate thermal expansion,and anisotropic compressibility,and the unique lay-ered structure is inspiring for exploring new layered ternary ceramics.

关键词： New ternary carbide MAX phase Thermal expansion Elastic constants Anisotropy

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城市蓝绿空间降温绩效评估及提升策略——以北京市为例

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地理科学 2024年第8期44卷 1376-1386页

作者：李建春 Chen y Wendy 袁文华山东师范大学商学院山东济南250358 香港大学地理系中国香港999077

绿地和水体对缓解热岛效应和改善生态环境效果显著,但因城市空间稀缺导致建设机会成本高,提升蓝绿空间绩效研究亟需深化。本文构建基于成本−收益分析的降温绩效评估模型,定量测量不同规模和类型的蓝绿空间斑块降温效果,以北京市为研究区... 详细信息

绿地和水体对缓解热岛效应和改善生态环境效果显著,但因城市空间稀缺导致建设机会成本高,提升蓝绿空间绩效研究亟需深化。本文构建基于成本−收益分析的降温绩效评估模型,定量测量不同规模和类型的蓝绿空间斑块降温效果,以北京市为研究区,利用2010—2020年3期土地利用与地表温度数据,评估大于1 hm^(2)蓝绿空间辐射范围的降温绩效。主要研究结论如下:①研究期内北京市蓝绿空间面积不断增加,呈现由小型面积(Ac)(1≤Ac<2 hm^(2))为主向中型(2≤Ac<10 hm^(2))和大型(Ac≥10 hm^(2))转变;水域持续增加,而林地、草地和混合类型减少;三环以内老城区面积基本持平,而四环减少、五环增多。②根据缓冲区降温模型,北京市蓝绿空间的降温区范围不断增加,从类型结构上看,大中型蓝绿空间形成的降温区增加,而小型蓝绿空间的降温区减少;林地面积虽然减少,但其降温区面积却在增加,而水体降温区面积增长不及自身面积增长。③不同类型蓝绿空间绩效水平呈现先上升后降低的特征,小型和中型混合类型、大型水体的降温绩效比其他同等规模的绩效更好。因此,优化蓝绿规模和类型结构、调整空间形态布局、改善生态空间质量对充分发挥蓝绿空间降温效应起到重要作用,为城市生态环境改善与可持续发展提供新思路。

关键词：蓝绿空间成本−收益分析降温绩效生态福祉

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Chronic hepatitis B virus infection in Eastern Ethiopia:Clinical characteristics and determinants of cirrhosis

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World Journal of Hepatology 2024年第7期16卷 995-1008页

作者： Nejib y Ismael Semir A Usmael Nega B Belay Hailemichael Desalegn Mekonen Asgeir Johannessen Stian MS Orlien Haramaya University College of Health and Medical SciencesHarar 252Ethiopia Aklilu Lemma Institute of Pathobiology Addis Ababa UniversityAddis Ababa 1000Ethiopia Regional Centre for Imported and Tropical Diseases Oslo University HospitalOslo 0450UllevålNorway Internal Medicine Gastroenterology and Hepatology UnitSaint Paul’s Hospital Millennium Medical CollegeAddis Ababa 1000Ethiopia Department of Infectious Disease Vestfold Hospital TrustTønsberg 3103Norway Institute of Clinical Medicine Oslo UniversityOslo 0318Norway Department of PediatricsOslo UniversityOslo 0450UllevålNorway

BACKGROUND Chronic hepatitis B(CHB)virus infection is a major cause of liver-associated morbidity and mortality,particularly in low-income countries.A better understanding of the epidemiological,clinical,and virological characteristics of CHB will guide appropriate treatment strategies and improve the control and management of CHB in *** To investigate the characteristics of CHB in Eastern Ethiopia and assess the efficacy and safety of antiviral *** This cohort study included 193 adults who were human immunodeficiency virus-negative with CHB between June 2016 and December *** assessments included chemistry,serologic,and viral markers.χ^(2) tests,Mann-Whitney U tests,and logistic regression analyses were used to identify the determinants of *** disoproxil fumarate(TDF)was initiated using treatment criteria from the Ethiopian CHB pilot *** A total of 132 patients(68.4%)were men,with a median age of 30 years[interquartile range(IQR):24-38].At enrollment,60(31.1%)patients had cirrhosis,of whom 35(58.3%)had decompensated *** use,hepatitis B envelope antigen positivity,and a high viral load were independently associated with ***,66 patients(33.4%)fulfilled the treatment criteria and 59(30.6%)started *** 29 patients who completed 24 months of treatment,the median aspartate aminotransferase to platelet ratio index declined from 1.54(IQR:0.66-2.91)to 1.10(IQR:0.75-2.53)(P=0.002),and viral suppression was achieved in 80.9%and 100%of patients after 12 months and 24 months of treatment,*** the treated patients,12(20.3%)died within the first 6 months of treatment,of whom 8 had decompensated *** This study highlights the high prevalence of cirrhosis,initial mortality,and the efficacy of TDF *** up measures to prevent and control CHB infections in Ethiopia is crucial.

关键词： Chronic hepatitis B Cirrhosis Cohort study Resource-limited settings Sub-Saharan Africa

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基于极限分析上限法的地震作用下分层地基盾构隧道开挖面稳定性研究

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岩土力学 2024年第4期45卷 1201-1213页

作者：张治国罗杰朱正国 PAN y T 孙苗苗上海理工大学环境与建筑学院上海200093 石家庄铁道大学省部共建交通工程结构力学行为与系统安全国家重点实验室河北石家庄050043 新加坡国立大学土木与环境工程系新加坡119077 浙大城市学院土木工程系浙江杭州310015 浙大城市学院城市基础设施智能化浙江省工程研究中心浙江杭州310015

目前针对盾构隧道开挖面稳定性的研究还较少考虑土体分层特性和地震作用的耦合影响,因此构建了一种在分层土体中考虑地震作用的开挖面三维对数螺旋破坏模型进行研究。首先,将地震引起的动态响应通过拟静力法简化为水平和竖直两个方向上... 详细信息

目前针对盾构隧道开挖面稳定性的研究还较少考虑土体分层特性和地震作用的耦合影响,因此构建了一种在分层土体中考虑地震作用的开挖面三维对数螺旋破坏模型进行研究。首先,将地震引起的动态响应通过拟静力法简化为水平和竖直两个方向上的惯性力作用;其次,在均质土体中的三维对数螺旋破坏机制的基础上,将其改进为适用于分层土体的三维对数螺旋破坏机制;再次,根据上限定理,在虚功率方程中引入地震惯性力所做功率,得到考虑土体分层特性和地震作用条件下的盾构隧道开挖面支护力的上限解;最后,将上限理论解与三维数值模拟结果和既有模型试验结果进行对比,得到了较好的一致性。此外,针对水平地震加速度系数和地层厚度对关键物理特征进行了影响因素分析。结果表明,当比例系数ζ>0时,极限支护力随水平地震加速度系数的增大显著增大;当ζ<0时,极限支护力随水平地震加速度系数增大而增大的趋势减弱。当水平地震加速度系数kh=0时,即在无地震作用情况下,归一化极限支护力不随ζ的变化而变化;在上硬下软土层中,下部土层厚度比的增大会引起极限支护力的增大,在上软下硬土层中,下部土层厚度比的增大会引起极限支护力的减小。

关键词：盾构隧道开挖面稳定性地震作用分层土体上限定理

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Hybrid-Vlasov simulation of soft X-ray emissions at the Earth’s dayside magnetospheric boundaries

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Earth and Planetary Physics 2024年第1期8卷 70-88页

作者： M.Grandin H.K.Connor S.Hoilijoki M.Battarbee y.Pfau-Kempf U.Ganse K.Papadakis M.Palmroth Department of Physics University of HelsinkiHelsinkiFinland NASA Goddard Space Flight Center GreenbeltMD20771USA Space and Earth Observation Centre Finnish Meteorological InstituteHelsinkiFinland

Solar wind charge exchange produces emissions in the soft X-ray energy range which can enable the study of near-Earth space regions such as the magnetopause,the magnetosheath and the polar cusps by remote sensing *** Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)and Lunar Environment heliospheric X-ray Imager(LEXI)missions aim to obtain soft Xray images of near-Earth space thanks to their Soft X-ray Imager(SXI)*** earlier modeling works have already simulated soft X-ray images as might be obtained by SMILE SXI during its mission,the numerical models used so far are all based on the magnetohydrodynamics description of the space *** investigate the possible signatures of ion-kinetic-scale processes in soft Xray images,we use for the first time a global hybrid-Vlasov simulation of the geospace from the Vlasiator *** simulation is driven by fast and tenuous solar wind conditions and purely southward interplanetary magnetic *** first produce global X-ray images of the dayside near-Earth space by placing a virtual imaging satellite at two different locations,providing meridional and equatorial *** then analyze regional features present in the images and show that they correspond to signatures in soft X-ray emissions of mirrormode wave structures in the magnetosheath and flux transfer events(FTEs)at the *** results suggest that,although the time scales associated with the motion of those transient phenomena will likely be significantly smaller than the integration time of the SMILE and LEXI imagers,mirror-mode structures and FTEs can cumulatively produce detectable signatures in the soft X-ray *** instance,a local increase by 30%in the proton density at the dayside magnetopause resulting from the transit of multiple FTEs leads to a 12%enhancement in the line-of-sight-and time-integrated soft X-ray emissivity originating from this ***,a proton density increase by 14%in the magnetosheath

关键词： magnetosphere magnetosheath numerical simulation SMILE LEXI soft X-ray emissions hybrid-Vlasov model polar cusp flux transfer events mirror-mode waves

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Ground-state mass of ^(22)Al and test of state-of-the-art ab initio calculations

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Chinese Physics C 2024年第3期48卷 72-78页

作者：孙铭泽于越王新鹏王猛李健国张玉虎 K.Blaum 陈祖毅陈瑞九邓涵宇付超义葛文文黄文嘉焦红扬李红蕙李宏福罗胤芳廖挺 yuALitvinov 司敏帅鹏史金阳王茜邢元明徐星徐瑚珊许甫荣袁琪 T.yamaguchi 颜鑫亮杨建成原有进周小红周旭张敏曾奇 CAS Key Laboratory of High Precision Nuclear Spectroscopy Institute of Modern PhysicsChinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Max-Planck-Institut für Kernphysik Saupfercheckweg 169117 HeidelbergGermany GSI Helmholtzzentrum für Schwerionenforschung Planckstraße 164291 DarmstadtGermany Advanced Energy Science and Technology Guangdong Laboratory Huizhou516007China State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China Department of Physics Saitama UniversitySaitama 338-8570Japan School of Nuclear Science and Engineering East China University of TechnologyNanchang 330013China

The ground-state mass excess of the T_(z)=−2 drip-line nucleus ^(22)Al is measured for the first time as 18103(10)keV using the newly-developed Bρ-defined isochronous mass spectrometry method at the cooler storage ring in *** new mass excess value allowed us to determine the excitation energies of the two low-lying 1+states in ^(22)Al with significantly reduced uncertainties of 51 *** compared to the analogue states in its mirror nucleus ^(22)F,the mirror energy differences of the two 1^(+)states in the ^(22)Al-^(22)F mirror pair are determined to be−625(51)keV and−330(51)*** excitation energies and mirror energy differences are used to test the state-of-the-art ab initio valence-space in-medium similarity renormalization group calculations with four sets of interactions derived from the chiral effective field *** mechanism leading to the large mirror energy differences is investigated and attributed to the occupation of theπs_(1/2) orbital.

关键词： nuclear mass Bρ-defined IMS mirror energy difference ab initio VS-IMSRG calculations chiral interactions

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Stubborn Hypoxia in Neonates with D-Transposition of the Great Arteries after Arterial Switch Operation: Central Sleep Apnea as the Cause and Potential Indicator of Brain Immaturity

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Congenital Heart Disease 2024年第2期19卷 185-195页

作者： Camden L.Hebson Kyle Bliton Amr y.Hammouda Kaitlyn Barr W.Hampton Gray Mohini Gunnett Waldemar F.Carlo Department of Pediatrics Division of Pediatric CardiologyUniversity of Alabama BirminghamBirmingham35233USA Department of Pediatrics Division of Pediatric PulmonologyUniversity of Alabama BirminghamBirmingham35233USA Department of Pediatrics University of Alabama BirminghamBirmingham35233USA Department of Surgery Division of Cardiothoracic SurgeryUniversity of Alabama BirminghamBirmingham35233USA

D-transposition of the great arteries(d-TGA)is surgically repaired with the arterial switch operation(ASO)with excellent results,however short and long-term morbidities still develop including neurocognitive *** significant central sleep apnea is uncommon in non-premature infants,but when present indicates immature autonomic control of respiration likely due to a neurologic *** report the unanticipatedfinding of central sleep apnea in four-term neonates with d-TGA after uncomplicated ASO,with the short-term complication of delayed hospital discharge and long-term concerns regarding this early marker of brain immaturity and its hindrance to normal *** this report,we will review each patient’s clinical course and then examine the literature on pediatric central sleep apnea,neurodevelopmental outcomes after ASO,and the important overlap of these entities in the care of patients going forward.

关键词： Transposition congenital heart disease sleep apnea polysomnography

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Investigating the impact of dynamic structural changes of Au/rutile catalysts on the catalytic activity of CO oxidation

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Carbon Energy 2024年第4期6卷 222-232页

作者： Xiaochun Hu Qianwenhao Fan Mingwu Tan yuqing Luo Xianyue Wu Manoel y.Manuputty Jie Ding Tej S.Choksi Markus Kraft Rong Xu Zhiqiang Sun Wen Liu School of Energy Science and Engineering Central South UniversityChangshaChina School of Chemistry Chemical Engineering and BiotechnologyNanyang Technological UniversitySingaporeSingapore Cambridge Centre for Advanced Research and Education SingaporeSingapore Institute of Sustainability for Chemicals Energy and EnvironmentJurong IslandSingapore College of Chemistry and Chemical Engineering Central South UniversityChangshaChina Department of Chemical Engineering and Biotechnology University of CambridgeCambridgeUK

The surface properties of oxidic supports and their interaction with the supported metals play critical roles in governing the catalytic activities of oxide‐supported metal *** metals are supported on reducible oxides,dynamic surface reconstruction phenomena,including strong metal–support interaction(SMSI)and oxygen vacancy formation,complicate the determination of the structural–functional relationship at the active ***,we performed a systematic investigation of the dynamic behavior of Au nanocatalysts supported on flame‐synthesized TiO_(2),which takes predominantly a rutile phase,using CO oxidation above room temperature as a probe *** analysis conclusively elucidated a negative correlation between the catalytic activity of Au/TiO_(2) and the oxygen vacancy at the Au/TiO_(2) *** the reversible formation and retracting of SMSI overlayers have been ubiquitously observed on Au/TiO_(2) samples,the catalytic consequence of SMSI remains *** functional theory suggests that the electron transfer from TiO_(2) to Au is correlated to the presence of the interfacial oxygen vacancies,retarding the catalytic activation of CO oxidation.

关键词： CO oxidation electronic metal-support interactions flame‐synthesis metal-support interactions oxygen vacancy strong metal-support interaction

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Caudal hematopoietic tissue supports definitive erythrocytes via epoa and is dispensable for definitive neutrophils

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Journal of Genetics and Genomics 2024年第6期51卷 669-672页

作者： Zhujuan Huang yongtai Xu Zhongkai Qiu yunyun Jiang Jiaye Wu Qing Lin Sicong He Jianan y.Qu Jiahao Chen Jin Xu Innovation Centre of Ministry of Education for Development and Diseases School of MedicineSouth China University of TechnologyGuangzhouGuangdong 510006China Department of Biology School of Life SciencesSouthern University of Science and TechnologyShenzhenGuangdong 518055China Department of Electronic and Computer Engineering The Hong Kong University of Science and TechnologyKowloonHongkong 999077China

The blood system originates from hematopoietic stem cells(HSCs),capable of self-renewal and differentiation,generating diverse blood cell types(Eaves,2015;Lucas,2021).The concept of the hematopoietic niche was first proposed in 1978(Schofield,1978),which is crucial for maintaining hematopoietic *** following studies,particularly in mammals,have utilized targeted genetic manipulation to identify and define these niches.

关键词： hematopoietic manipulation utilized

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Fast efficient photon deceleration in plasmas by using two laser pulses at different frequencies

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Matter and Radiation at Extremes 2024年第3期9卷 11-18页

作者： y.X.Wang X.L.Zhu S.M.Weng P.Li X.F.Li H.Ai H.R.Pan Z.M.Sheng Key Laboratory for Laser Plasmas(moe) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of IFSA Shanghai Jiao Tong UniversityShanghai 200240China Research Center of Laser Fusion of China Academy of Engineering Physics MianyangSichuan 621900China State key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Tsung-dao Lee Institute Shanghai Jiao Tong UniversityShanghai 200240China

The generation of ultrashort high-power light sources in the mid-infrared(mid-IR)to terahertz(THz)range is of interest for applications in a number of fields,from fundamental research to biology and *** conventional laser technology,photon deceleration in plasma wakes provides an alternative approach to the generation of ultrashort mid-IR or THz ***,we present a photon deceleration scheme for the efficient generation of ultrashort mid-IR or THz pulses by using an intense driver laser pulse with a relatively short wavelength and a signal laser pulse with a relatively long *** signal pulse trails the driver pulse with an appropriate time delay such that it sits at the front of the second wake bubble that is driven by the driver *** to its relatively long wavelength,the signal pulse will be subjected to a large gradient of the refractive index in the plasma wake ***,the photon deceleration in the plasma wake becomes faster and more efficient for signal pulses with longer *** greatly enhances the capacity and efficiency of photon deceleration in the generation of ultrashort high-power light sources in the long-wavelength IR and THz spectral ranges.

关键词： laser ultrashort photon

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