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(Lu_(1/7)yb_(1/7)Sc_(1/7)Er_(1/7)y_(1/7)Ho_(1/7)Dy_(1/7))_(2)Si_(2)O_(7)high entropy rare-earth disilicate with low thermal conductivity and excellent resistance to CmAS corrosion

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Journal of Advanced Ceramics 2024年第5期13卷 549-560页

作者： Xu Wang mingyu meng Feihan Xu Ling liu Lihong Gao Shizhen Zhu Zhuang ma School of materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Science and Technology on materials under Shock and Impact Beijing 100081China Tangshan Research Institute Beijing Institute of TechnologyTangshan 063000China

Low thermal conductivity,compatible thermal expansion coefficient,and good calcium–magnesium–aluminosilicate(CmAS)corrosion resistance are critical requirements for environmental barrier coatings used on silicon-based ***2Si2O7(RE=rare earth)has been widely recognized as one of the most promising candidates for environmental barrier coatings due to its good water vapor corrosion ***,the relatively high thermal conductivity and poor resistance to CmAS corrosion have limited its practical *** by the high entropy effect,in this work,a novel rare earth disilicate(Lu_(_(1/7))yb_(_(1/7))Sc_(_(1/7))Er_(_(1/7))y_(_(1/7))Ho_(_(1/7))Dy_(_(1/7)))2Si2O7((7RE_(_(1/7)))2Si2O7)has been designed and synthesized by a solid reaction process.(7RE_(_(1/7)))2Si2O7 showed a low thermal conductivity of 1.81 W·m^(−1)·K^(−1)at 1273 ***,the thermal expansion coefficient of(7RE_(_(1/7)))_(2)Si_(2)O_(7)(4.07×10^(−6)℃^(−1)from room temperature(RT)to 1400℃)is close to that of the SiC-based ceramic matrix composites(SiC-CmCs)((4.5–5.5)×10^(−6)℃^(−1)).Additionally,(7RE_(_(1/7)))2Si2O7 exhibited excellent resistance to CmAS *** exposed to CmAS at 1300℃for 48 h,the reaction layer thickness was 22μ*** improved performance of(7RE_(_(1/7)))2Si2O7 highlights its potential as a promising candidate for thermal/environmental barrier coatings.

关键词： high entropy disilicate (Lu_(1/7)yb_(1/7)Sc_(1/7)Er_(1/7)y_(1/7)Ho_(1/7)Dy_(1/7))_(2)Si_(2)O_(7)((7RE_(1/7))_(2)Si_(2)O_(7)) high-temperature thermal properties calcium-magnesium-aluminosilicate(CmAS)corrosion

Stable hydrogen-bonded organic frameworks and their photo-and electro-responses

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Nano Research 2024年第8期17卷 7675-7699页

作者： ying Hou Xin-Song Huang Sheng-Hao Gong Chen liu yangyang liu Tian-Fu liu State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China University of Chinese Academy of Sciences Beijing 100049China Department of Chemistry and Biochemistry California State UniversityLos AngelesCalifornia 90032USA College of Chemistry and materials Science Fujian Normal UniversityFuzhou 350007China

Hydrogen-bonded organic frameworks(HOFs)are a recent class of porous materials that have garnered considerable research interest owing to their distinctive *** can be constructed through judicious selection of H-bonding motifs,which are further enforced by other weak intermolecular interactions such asπ–πstacking,van der Waals forces,and framework *** advantage of these interactions,we can expand the functional field of HOFs by introducing active ***,researchers have made substantial advancements in using HOFs for chemical sensing,catalysis,proton conduction,biological applications,and *** low bonding energy of H-bonds allows for precise control over the concentration of ligands in solvents,forming diverse HOF *** varied structures offer significant advantages for producing HOFs with photo-responsive and electro-responsive ***,the presence of H-bonds in HOFs results in their inherent lower stability compared to metal-organic frameworks(mOFs)and covalent-organic frameworks(COFs)formed via coordination and covalent bonds,*** a result,the pursuit of stable and innovative HOF materials with novel functional sites remains an ongoing *** review provides an overview of recent research progress in the development of new strategies for stable HOF synthesis and applications of HOFs with stimuli-responsive *** first classified all synthetic methods reported to date and discussed the stable HOFs synthesized,as well as their unique properties and *** addition,we summarized the applications of HOFs utilizing their synergistic responses to external stimuli,including photo,electrical,pressure,and chemical *** systematically reviewed stable HOF synthesis and applications,which m.y.lead to a deeper understanding of the structure–activity relationship for these materials and guide future HOF design.

关键词： stable hydrogen-bonded organic frameworks(HOFs) photo-response electro-response photoelectric synergistic response

Ren-integrable and ren-symmetric integrable systems

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Communications in Theoretical Physics 2024年第3期76卷 62-69页

作者： S y Lou School of Physical Science and Technology Ningbo UniversityNingbo315211China

A new type of symmetry,ren-symmetry,describing anyon physics and corresponding topological physics,is ***-symmetry is a generalization of super-symmetry which is widely applied in super-symmetric physics such as super-symmetric quantum mechanics,super-symmetric gravity,super-symmetric string theory,super-symmetric integrable systems and so *** and Grassmann numbers are,in some sense,dual conceptions,and it turns out that these conceptions coincide for the ren situation,that is,a similar conception of ren-number(R-number)is devised for *** particular,some basic results of the R-number and ren-symmetry are exposed which allow one to derive,in principle,some new types of integrable systems including ren-integrable models and ren-symmetric integrable *** examples of ren-integrable KdV-type systems and ren-symmetric KdV equations are explicitly given.

关键词： symmetries integrable systems anyon physics extended supersymmetry ren-symmetry

On electro-acoustic characteristics of a marine broadband sparker for seismic exploration

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Journal of Oceanology and Limnology 2024年第3期42卷 760-771页

作者： Jing LI Kai liu Liancheng ZHANG Chenguang liu yanliang PEI Baohua liu Key Laboratory of marine Geology and metallogency First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory of marine Geology Laoshan LaboratoryQingdao 266237China Key Laboratory of Fluid Transmission Technology of Zhejiang Province Zhejiang Sci-Tech UniversityHangzhou 310018China Key Laboratory of Submarine Acoustic Investigation and Application of Qingdao(Preparatory) Qingdao 266061China Key Laboratory of Deep Sea mineral Resources Development Shandong(Preparatory)Qingdao 266061China

The construction of major marine infrastructure projects and the exploration and development of deep-sea mineral resources require fine imaging of seabed strata and *** highresolution marine seismic exploration based on a high broadband sparker source is an important approach to reveal seabed stratum and reservoir structure,and identify *** optimize the performance of sparker seismic source,we investigated the electro-acoustic characteristics of spark discharge under conditions of different charging voltages and electrode *** show that the sound source level increased with the increase of the charging voltage,whereas the main frequency decreased when the charging voltage *** addition,it was found that the charging capacitance had more obvious influence on the main frequency than the sound source level *** the load energy decreased with increasing electrode number,the sound source level still increased but the main frequency ***,the primary to bubble(P/B)ratio increased with the increase of the electrode *** gain a deeper insight into the electro-acoustic characteristics,we investigate the relationship between sound source level and power peak,from which a good correlation was observed.A more practical statistical analysis on the rise rate of current was processed,and a perfect logarithmic function was ***,we found that the main frequency was most possibly subjected to the electrical energy,especially the charging energy per *** results indicate that the charging energy per electrode less than 10 J could increase the main frequency to above 300 *** last,the main frequency could be reduced to 20 Hz when the charging energy of a single-electrode discharge was enhanced to over 4 *** study shall be helpful in developing a sparker seismic source and improving the performance for marine engineering exploration and geohazard assessment.

关键词： high-resolution marine seismic exploration sparker seismic source sound source level main frequency electro-acoustic characteristics

Design and performance investigation of modified dual reflector parabolic trough collector with double planar mirrors

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Science China(Technological Sciences) 2024年第3期67卷 902-918页

作者： LI Peijing liu TaiXiu QIN yuanLong LI JiChao liu QiBin School of Energy Powerand Mechanical EngineeringNorth China Electric Power University Beijing 226China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Department of Thermal Science and Energy Engineering University of Science and Technology of ChinaHefei 230027China

In a typical parabolic trough collector(PTC), sunlight is concentrated at the bottom of the absorber tube. This concentrated solar flux leads to uneven heat distribution, resulting in high local temperatures and significant thermal stress on the absorber *** limitations have restricted the application of PTCs in solar thermochemistry and other fields and have impacted their safe operation. In this study, a new PTC with dual planar mirrors(DPmS) is proposed to homogenize the circumferential solar flux distribution of the absorber tube. A design method and single-objective optimization of the new PTC with a DPmS are proposed,and an uncertainty analysis of the operational and structural parameters is performed. A coupled light-heat-structure numerical model was developed to study the heat transfer performance and structural mechanical properties. The thermodynamic properties of the PTC with DPmS under different boundary conditions were analyzed. The results show that the circumferential temperature difference of the new PTC is within 2.6 K, and the circumferential thermal deformation is within 0.9 mm under typical working conditions(the inlet velocity of the heat transfer fluid is 3 m/s, inlet temperature is 573.15 K, and the direct normal irradiance is 1000 W/m^(2)). Compared with conventional PTCs, the circumferential temperature difference is reduced by 74%–90%, and the maximum thermal deformation along the y-axis is reduced by more than 95% under all working conditions(1–5 m/s, 373.5–675.15 K, 200–1000 W/m^(2)). The new PTC maintains the uniformity of the circumferential solar flux distribution for different operating parameters(sun incident angle of 0°–3°) and installation errors(±3 mm), is suitable for solar energy applications in various fields, and has the potential for large-scale applications.

关键词： solar thermal energy parabolic trough collector secondary reflector solar flux distribution optical optimization

Synthesis,Structures,and Chiroptical Properties of NBN-Doped Helicenes with Boron Atoms in the Inner Rims

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Precision Chemistry 2024年第1期2卷 28-39页

作者： Weiwen Zhuang yujian liu Ziqi Deng yu Guo Philip C.y.Chow David Lee Phillips Wei Jiang Zhaohui Wang Junzhi liu State Key Laboratory of Synthetic Chemistry HKU-CAS Joint Laboratory on New Materials and Department of ChemistryThe University of Hong KongPokfulamHong KongChina Key Laboratory of Organic Optoelectronics and molecular Engineering Department of ChemistryTsinghua UniversityBeijing 100084China Department of mechanical Engineering The University of Hong KongPokfulamHong KongChina

The precise synthesis of helicenes with topologically defined length and specific heteroatomic perturbation in the screw-like conjugated skeletons plays an emerging role in the manipulation of chiral ***,selective,and programmable routes to helicenes or heterohelicenes are highly desirable yet challenging for structure-chiroptical property relationship ***,we report the synthesis and characterization of NBN-doped helicenes with boron atoms in the inner rims,enabled by the highly regioselective one-pot borylation of rationally designed precursors with,namely,fold-in or pan-out *** incorporation of nonbonded boron and nitrogen atoms resulted in narrow-band emission and improved optical properties for the single-stranded carbon *** addition,numbers and arrangement modes of fused six-membered rings have distinct effects on configurational stability and chiroptical properties,revealing that BN-[6]H with strong circular dichroism is a promising candidate for chiral *** combination of experimental and theoretical studies on these helical structures might provide insights into the design of helically chiral small-molecule-based sensors or emitters.

关键词： Nitrogen-boron Helicenes Borylation Chiroptical properties Narrow-band emission

Engineering of efficient visible light photocatalysts:Ti_(1-x+y)Cu_(x)La_(y)O_(2)(x=0.03;y=0,0.005,0.01) compositions

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Journal of Rare Earths 2024年第3期42卷 497-505,I0003页

作者： S.m.y.kout A.m.y.ussef Inorganic Chemistry Department National Research Centre(NRC)El Buhouth StDokkiCairo12622Egypt

In dye-photocatalysis, widening the wavelengths absorption range of catalysts as well as aborting the recombination of the photoexcited charge carriers(electrons-holes pairs) are of paramount *** the current study, we report the photocatalytic characteristics of four compositions composed of TiO_(2),Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders for two harmful dyes(Congo red and methylene blue). The X-ray diffraction technique verified the configuration of mixed anatase and rutile phases in pure TiO_(2)and Ti_(0.97)Cu_(0.03)O_(2)powders while Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders possess anatase phase only. The changes of the band gap structure and dimensions of the unit cell volume of TiO_(2)confirm the substitution of Ti^(4+)sites by Cu^(2+)and La^(3+)ions. Remarkable widening of wavelengths absorption with formation of long absorption tails were found in TiO_(2)(3.13 e V) through insertion of La^(3+)plus Cu^(2+)ions. Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)samples exhibit a visible light band gap of 2.3 and 2.7 e V, respectively. Based on SEm images, incorporation of Cu^(2+)and La^(3+)ions influences the surface morphology of TiO_(2). The resulting Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders present enhanced photocatalytic activity towards Congo red dye degradation compared to pure one under natural solar spectrum. The best Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst exhibits superior photocatalytic activity of 96% for 10 ppm CR dye in 20 min as well as above average photocatalytic efficiency of 63% for 30 ppm CR dye in 120 min. As well, it showed acceptable photodegradation activity of 52% for 30 ppm mB solution in 140 min of sunlight irradiation. The heightened photodegradation efficiency of Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst can be clarified in terms of higher ch

关键词： Semiconductor TiO_(2) Rare earths Congo red methylene blue Solar spectrum Photodegradation

Approaching Ultimate Synthesis Reaction Rate of Ni-Rich Layered Cathodes for Lithium-Ion Batteries

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Nano-micro Letters 2024年第10期16卷 392-402页

作者： Zhedong liu Jingchao Zhang Jiawei Luo Zhaoxin Guo Haoran Jiang Zekun Li yuhang liu Zijing Song Rui liu Wei-Di liu Wenbin Hu yanan Chen School of materials Science and Engineering Tianjin UniversityTianjin 300072People's Republic of China School of materials Science and Engineering Shandong University of Science and TechnologyQingdao 266590People's Republic of China Australian Institute of Bioengineering and Nanotechnology The University of QueenslandSt LuciaQLD 4072Australia

Nickel-rich layered oxide LiNi_(x)Co_(y)mnzO_(2)(NCm,x+y+z=1)is the most promising cathode material for high-energy lithium-ion ***,conventional synthesis methods are limited by the slow heating rate,sluggish reaction dynamics,high energy consumption,and long reaction *** overcome these chal-lenges,we first employed a high-temperature shock(HTS)strategy for fast synthesis of the NCm,and the approaching ultimate reaction rate of solid phase transition is deeply investigated for the first *** the HTS process,ultrafast average reaction rate of phase transition from Ni_(0.6)Co_(0.2)mn_(0.2)(OH)_(2) to Li-containing oxides is 66.7(%s^(-1)),that is,taking only 1.5 *** ultrahigh heating rate leads to fast reaction kinetics,which induces the rapid phase transition of NCm *** HTS-synthesized nickel-rich layered oxides perform good cycling performances(94%for NCm523,94%for NCm622,and 80%for NCm811 after 200 cycles at 4.3 V).These findings might also assist to pave the way for preparing effectively Ni-rich layered oxides for lithium-ion batteries.

关键词： Nickel-rich layered oxides High-temperature shock Solid reaction kinetics Phase transition Reaction rate

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