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Syntheses of new di-nuclear and tetra-nuclear lanthanide 9-anthracenecarboxylates:Magnetocaloric effect,slow magnetic relaxation and luminescent properties

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Journal of Rare Earths 2024年第6期42卷 1101-1109,I0004页

作者： Xing Liu Ruonan yang Lu Zhang Jian Zhou chunmei Huang Huahong Zou Zunhong Xiao chongqing Key Laboratory of Inorganic.f.nctional Materials College of ChemistryChongqing Normal UniversityChongqing401331China Key Laboratory for the chemistry and Molecular Engineering of Medicinal Resources(Ministry of Education of china) School of Chemistry and Chemical Engineering of Guangxi Normal UniversityGuilin541004China School of chemistry and Materials Guizhou Normal UniversityGuiyang550025China

Lanthanide complex-based materials with magnetic and luminescent properties have received a great deal of attention,owing to their importantly potential applications in diverse *** this work,the 9-anthracenecarboxylic acid(9-Haca)as bridging ligand was applied in combination with optically activeπ-conjugated 2,4,6-tri(2-pyridyl)-1,3,5-triazine(tptz)to construct a series of new di-nuclear and tetranuclear lanthanide 9-anthracenecarboxylates[La_(2)(9-aca)_(6)(tptz)_(2)(μ-H_(2)O)]·0.25H_(2)O(1),[Ln_(2)(9-aca)_(6)(tptz)_(2)(H_(2)O)_(2)]·0.5AQ·cH_(3)cOOH_(2)H_(2)O[Ln=Sm(2a),Eu(2b),Gd(2c),Tb(2d),Dy(2e),Tm(2f);AQ=9,10-anthracenedione]and[Ln_(4)(9-aca)_(10)(tptz)_(2)(cH3cOO)2]·H_(2)O[Ln=Eu(3a),Gd(3b),Dy(3c)].1 displays a di-nuclear centrosymmetric moiety[La_(2)(9-aca)_(6)(tptz)_(2)(μ-H_(2)O)]built up from two complex[La(9-aca)_(2)(tptz)]groups bridged by one H_(2)O molecule and two syn-syn-μ2-η1:η1-9-aca-bridging ligands,while 2a-2f are isostructural and co mprise another di-nuclear centrosymmetric moieties[Ln_(2)(9-aca)_(6)(tptz)_(2)(H_(2)O)_(2)]based on two complex[Ln(9-aca)_(2)(tptz)(H_(2)O)]groups connected by two syn-syn-μ2-η1:η1-9-aca-bridging ligands,3a-3c are isostructural and show tetra-nuclear centro symmetric moieties[Ln4(9-aca)10(tptz)2(cH3cOO)2]containing three types of coordination modes of *** present compounds offer the only examples of lanthanide 9-anthracenecarboxylates decorated by optically active *** investigations of 2a,2c-2f,and 3b-3c indicate that 3c is typical of slow relaxation of the magnetization,while 2c and 3b show significant magnetocaloric effect(McE)with the value of-ΔSm of 5.26 J/(kg·K)at 4 K and 15.65 J/(kg·K)at 2 K(ΔH=7 T),*** luminescent properties were also studied and reveal that the characteristic luminescent properties of the 7r-conjugated aromatic ligands are introduced into magnetic lanthanide 9-anthracenecarboxylates,simultaneously exhibiting slow magnetic relaxation(or McE)and luminescen

关键词： Lanthanide complexes Luminescence Magnetic properties Magnetocaloric effect Slow magnetic relaxation Rare earths

comparative analysis of microstructure,mechanical,and corrosion properties of biodegradable Mg-3Y alloy prepared by selective laser melting and spark plasma sintering

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Journal of Magnesium and Alloys 2024年第4期12卷 1496-1510页

作者： P.Minárik M.Zemková S.Šašek J.Dittrich M.Knapek f.Lukáˇc D.Koutný J.Jaroš R.Král faculty of Mathematics and Physics Charles UniversityKe Karlovu 5Praha 12116Czech Republic Research centre University ofŽilinaUniverzitná8215/1Žilina 01026Slovakia Institute of Plasma Physics of the czech Academy of Sciences Za Slovankou 1782/318200 Praha 8Czech Republic Institute of Machine and Industrial Design Brno University of TechnologyTechnická2896/2Brno 61669Czech Republic

This work explored possibilities of biodegradable magnesium alloy Mg-3Y preparation by two modern powder metallurgy techniques–spark plasma sintering(SPS)and selective laser melting(SLM).The powder material was consolidated by both methods utilising optimised parameters,which led to very low porosity(∼0.3%)in the SLM material and unmeasurably low porosity in the SPS *** main aim of the study was the thorough microstructure characterisation and interrelation between the microstructure and the functional properties,such as mechanical strength,deformability,and corrosion *** materials showed comparable strength of∼110 MPa in tension and compression and relatively good deformability of∼9%and∼21%for the SLM and SPS materials,*** corrosion resistance of the SPS material in 0.1 M Nacl solution was superior to the SLM one and comparable to the conventional extruded *** digital image correlation during loading and the cross-section analysis of the corrosion layers revealed that the residual porosity and large strained grains have the dominant negative effect on the functional properties of the SLM *** the other hand,one of the primary outcomes of this study is that the SPS consolidation method is very effective in the preparation of the W3 biodegradable alloy,resulting in material with convenient mechanical and degradation properties that might find practical applications.

关键词： Magnesium Yttrium Powder metallurgy Microstructure Mechanical strength corrosion resistance

A simplified dispersion-compensation microstructure fiber with seven cores

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Optoelectronics Letters 2024年第4期20卷 216-221页

作者： LI Wenchao WANG chao yang Hongda HANG Ying WANG Wei Intelligence and Information Engineering college Tangshan UniversityTangshan 063000China School of Information Science and Engineering Yanshan UniversityQinhuangdao 066004China

In order to compensate the dispersion accumulated in a single mode fiber(SMf)for higher communication capacity,a simplified dispersion-compensation microstructure fiber(Dc-MSf)with seven cores is proposed in this *** fiber’s cladding is made of pure silica without air holes,and its outer cores are composed of six germanium up-doped cylinders,which has the advantage of simple *** finite element method(fEM)and beam propagation method(BPM)are used to study the properties of the fiber,and the relationship between the structural parameters of the fiber and the dispersion,as well as the phase matching wavelength,is *** optimizing the structural parameters of the fiber,the dispersion of the fiber can reach-5291.47 ps·nm^(-1)·km^(-1) at 1550 nm,and the coupling loss to the conventional single-mode fiber is only 0.137 d *** with the conventional dispersion-compensation fiber,the fiber has lots of advantages,such as single mode transmission,easy to fabricate and low coupling loss with traditional SMf,etc.

关键词： fiber dispersion simplified

co-aromatization of methane and hexane over Pt encapsulated in ZSM-5 zeolite and the electronic effect of K promoters

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Science china chemistry 2024年第3期67卷 1017-1027页

作者： Bei Liu fan Wang Xiaomeng Dou Pengfei Li Hongwei Xiang Yong yang Peng He State Key Laboratory of coal conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China Department of chemistry Tsinghua UniversityBeijing 100084China National Energy R&D center for coal to Liquid fuels Synfuels China Technology Co.Ltd.Beijing 101407China University of chinese Academy of Sciences Beijing 101408China Leibniz-Institut für Katalyse e.V.an der Universitat Rostock Rostock 18059Germany

The co-aromatization of methane with higher hydrocarbons represents a promising route to valorize methane, an abundant but underexploited carbon resource. In this study, we elucidate a novel approach to enhance the catalytic co-aromatization of hexane and methane by confining Pt within zeolite catalysts and modulating its electron density. Our findings show that encapsulating Pt within MfI structure is pivotal for activating the feedstock and fostering the formation of aromatic products. Interaction between K atoms and the silanol nest forms siloxy groups which are critical for the stabilization of Pt species. Tuning the K content in PtSn@MfI catalysts adeptly alters the electronic configuration of Pt clusters. This modification is corroborated by infrared and X-ray photoelectron spectroscopy analysis, and density functional theory calculations. Remarkably, the catalyst with 0.8 wt% K exhibits an optimal Pt electron density, driving its superior efficacy in the co-aromatization reaction, converting 0.78 mol of methane for each mole of hexane processed. By employing ~(13)c isotopic labeling and solid-state NMR studies, we demonstrate the participation of methane in the adsorbed species inside the zeolite channel and its incorporation to the benzyl site of the substitute group and phenyl rings in aromatic compounds, underscoring the importance of Pt encapsulation.

关键词： Pt encapsulation MfI zeolite methane activation co-aromatization ^(13)c solid-state NMR

Enhanced red luminescence of ca_(3)Si_(2−x)M_(x)O_(7):Eu^(3+)(M=Al,P)phosphors via partial substitution of Si^(4+) for applications in white light-emitting diodes

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Rare Metals 2024年第2期43卷 736-748页

作者： Yu-Hao Ma Xi Gao Wen-Tao Zhang Zhen-Rui yang Zhou Zhao chen Qu college of Materials and chemistry and chemical Engineering Chengdu University of TechnologyChengdu610059China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China International Advanced Energy Science Research and Education center Graduate School of Energy ScienceKyoto UniversityYoshida-HonmachiKyoto606-8501Japan

A red-emitting phosphor ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)ions on the crystal structure and photoluminescence performance of ca_(2.91)Si_(2−x)M_(x)O_(7):0.09Eu^(3+) phosphors were *** X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)results revealed that the structure of ca_(3)Si_(2)O_(7) remained the same after the introduction of Al^(3+) and P^(5+) *** characteristic emission of Eu^(3+)-doped ca_(3)Si_(2−x)M_(x)O_(7) phosphors exhibited two main peaks at 617 nm(red)and 593 nm(orange)under excitation at 394 nm,which originated from the^(5)D_(0)→^(7)f_(2)and^(5)D_(0)→^(7)f_(1) electron transitions of Eu^(3+) *** the partial substitution of Al^(3+) and P^(5+),the red emission intensities of the ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu^(3+).Meanwhile,the luminescence intensities of the ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+) and ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) phosphors at 210℃ were 79.36%and 77.53%of those at 30°c,respectively,indicating their excellent thermal ***,the as-prepared ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+)and ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) red-emitting phosphors were combined with a near-ultraviolet chip of 395 nm to fabricate red-light-emitting diode(LED)and white(w)-LED devices with excellent chromaticity *** summary,Al^(3+)/P^(5+)-substituted ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) can serve as red-emitting phosphors for applications in w-LEDs.

关键词： ca_(3)Si_(2)O_(7) Red-emitting phosphor Structure substitution Luminescence enhancement crystal-field effect White light-emitting diode

Effect of exogenous additives on heavy metal passivation and nitrogen retention in pig manure composting

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frontiers of Agricultural Science and Engineering 2024年第3期11卷 468-484页

作者： Ziqi WANG Guotao SUN Jiamin WANG Gongshe yang college of Animal Science and Technology Northwest A&F UniversityYangling 712100China college of Horticulture Northwest A&F UniversityYangling 712100China

The widespread use of feed additives in intensive and large-scale pig farming has resulted in high levels of heavy metals in pig *** long-term application of organic.f.rtilizers containing high levels of heavy metals leads to the accumulation of heavy metals in the soil,which not only causes heavy metal pollution in the soil,and also affect food safety and endanger human *** is an economical and effective technical measures to achieve environmentally-sustainable treatment of pig manure and is a practical method to reduce the problem of heavy metals and to improve the resource value of pig *** composting process is accompanied by high temperatures and the production and emission of gases,and also lead to changes in the nitrogen content of the compost and provide opportunity for heavy metal passivation *** paper summarizes the forms and types of heavy metals present in pig manure and reviews the progress of research as well as the techniques and problems of in the composting process,and provides recommendations for research on heavy metal passivation and nitrogen retention in pig manure composting.

关键词： Additives composting heavy metals passivation nitrogen retention pig manure

A comprehensive Survey for Privacy-Preserving Biometrics: Recent Approaches, challenges, and future Directions

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computers, Materials & continua 2024年第2期78卷 2087-2110页

作者： Shahriar Md Arman Tao yang Shahadat Shahed Alanoud AlMazroa Afraa Attiah Linda Mohaisen School of computer Science and Technology Zhejiang Gongshang UniversityHangzhou310018China School of computer Science and Technology Hangzhou Dianzi UniversityHangzhou310018China college of computer and Information Sciences Princess Nourah bint Abdulrahman UniversityRiyadh84428Saudi Arabia faculty of computing and Information Technology King Abdulaziz UniversityJeddah21589Saudi Arabia

The rapid growth of smart technologies and services has intensified the challenges surrounding identity authenti-cation *** credentials are increasingly being used for verification due to their advantages over traditional methods,making it crucial to safeguard the privacy of people’s biometric data in various *** paper offers an in-depth exploration for privacy-preserving techniques and potential threats to biometric *** proposes a noble and thorough taxonomy survey for privacy-preserving techniques,as well as a systematic.f.amework for categorizing the field’s existing *** review the state-of-the-art methods and address their advantages and limitations in the context of various biometric modalities,such as face,fingerprint,and eye *** survey encompasses various categories of privacy-preserving mechanisms and examines the trade-offs between security,privacy,and recognition performance,as well as the issues and future research *** aims to provide researchers,professionals,and decision-makers with a thorough understanding of the existing privacy-preserving solutions in biometric recognition systems and serves as the foundation of the development of more secure and privacy-preserving biometric technologies.

关键词： Biometric modalities biometric recognition biometric security privacy-preserving security threats

Masses of the conjectured H-dibaryon at different temperatures

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chinese Physics c 2024年第8期48卷 83-93页

作者： Liang-Kai Wu Han Tang Ning Li Xin-yang Wang School of Physics and Electronic Engineering Jiangsu UniversityZhenjiang 212013China center for fundamental Physics School of Mechanics and PhysicsAnhui University of Science and TechnologyHuainan 232001China

We present a lattice QcD determination of masses of the conjectured H-dibaryon,denoted as mH,at nine different temperatures:T/T_(c)=0.24,0.63,0.76,0.84,0.95,1.09,1.27,1.52,and *** masses of baryons N,Σ,Ξ,andΛat different temperatures were also *** simulations were performed on an anisotropic lattice with N_(f)=2+1 flavours of clover fermion at a quark mass corresponding to mπ=384(4)*** thermal ensembles were provided by the fASTSUM collaboration,whereas the zero temperature ensembles were provided by the Hadspec *** also calculated the spectral density of the correlation function of those *** spectral density distributions show a rich peak structure at the lowest temperature;at intermediate temperatures,the mass values of those particles obtained by the extrapolation method reflect a two-peak *** the spectral density for the octet baryon becomes smooth at T/T_(c)=1.27,1.52,and 1.90,the spectral density for the H-dibaryon becomes smooth at T/T_(c)=*** T/T_(c)=0.24,the mass difference of the H-dibaryon andΛpair,expressed asΔm=m_(H)−2m_(Λ),was estimated to beΔm=−14.6(6.2)MeV,which suggests the existence of a bound H-dibaryon state.

关键词： lattice QcD H-dibaryon spectral function clover fermion finite temperature

Laboratory and numerical modelling of irrigation infiltration and nitrogen leaching in homogeneous soils

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Pedosphere 2024年第1期34卷 146-158页

作者： Lei WU Ruizhi LI Yan WANG Zongjun GUO Jiaheng LI Hang yang Xiaoyi MA Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas Ministry of EducationNorthwest A&F UniversityYangling 712100China Blackland Research and Extension center Texas A&M AgriLife ResearchTexas A&M UniversityTemple TX 76502USA State Key Laboratory of Soil Erosion and Dryland farming on the Loess Plateau Northwest A&F UniversityYangling 712100China college of Water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100China

Nitrogen (N) plays a key role in crop growth and production;however,data are lacking especially regarding the interaction of biochar,grass cover,and irrigation on N leaching in saturated soil *** soil columns with 20-cm diameter and 60-cm height were designed to characterize the effects of different grass cover and biochar combinations,i.e.,bare soil+0%biochar (control,cK),perennial ryegrass+0%biochar (c1),festuca arundinacea+0%biochar (c2),perennial ryegrass+1%biochar (c3),perennial ryegrass+2%biochar (c4),perennial ryegrass+3%biochar (c5),***+1%biochar (c6),***+2% biochar (c7),and ***+3%biochar (c8),on periodic irrigation infiltration and N leaching in homogeneous loess soils from July to December *** in cK were 10.2%–35.3%higher than those in c1 and *** perennial ryegrass and *** decreased the volumes of leachates and delayed the leaching process in the 1%,2%,and 3%biochar treatments,and the vertical leaching rate decreased with biochar *** N leaching losses were concentrated in the first few leaching tests,and both total N (TN) and nitrate (NO_(3)^(-))-N concentrations in cK and c1–c8 decreased with increasing leaching test *** addition (1%,2%,and 3%) could further reduce the leaching risk of NO_(3)^(-)-N and the NO_(3)^(-)-N loss decreased with biochar ***,compared to 1%biochar,2% biochar promoted the leaching of TN under both grass cover *** N leaching losses in cK,c1,c2,c3,c4,c6,and c7 were primarily in the form of NO_(3)^(-)-*** these treatments,cK,c1,and c2had the highest cumulative leaching fractions NO_(3)^(-)-N (>90%),followed by those in c3,c4,c6,and c7 (>80%).The cumulative leaching fraction of NO_(3)^(-)-N decreased with increasing leaching test times and biochar addition,and 3%biochar addition (i.e.,c5 and c8) reduced it to approximately 50%.The one-dimensional advective-dispersive-reactive transport equation can be used as an effective nume

关键词： leaching loss nitrate nitrogen biochar grass cover analytical modelling