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China Petrol.um Processing & Petrochemical.Technol.gy 2024年第2期26卷 72-80页

作者： Wang Yajun l.n l.i Xing jianqiang l.Xu Yang He Song Haiqing SINOPEC Research Institute of Petrol.um Processing Co. Ltd.Beijing 100083China State Key l.boratory of Engines Tianjin UniversityTianjin 300072China

The aim of this study was to investigate the oxidation reactivity and behavior of exhaust particul.te matter(PM)from diesel.*** sampl.s from two diesel.engines(1K,CY4102)with different emission l.vel. were col.ected by a thermophoretic system and a quartz *** oxidation reactivity,oxidation behaviors,and physicochemical.properties of the PM sampl.s were anal.zed using thermogravimetric anal.sis(TGA),high-resol.tion transmission el.ctron microscopy(HRTEM),Fourier-transform infrared spectrometry(FTIR),and Raman *** resul.s showed that there was a great difference in the oxidation reactivity of soot particl.s emitted by the two different diesel.engines.A qual.tative anal.sis of the factors infl.encing oxidation reactivity showed that the nanostructure,degree of graphitization,and rel.tive concentration of al.phatic C—H functional.groups were the most important factors,whereas no significant correl.tion was found between the primary particl. size and activation energy of the diesel.*** on the oxidation behavior anal.sis,the diesel.soot particl.s exhibited both internal.and surface oxidation modes during the oxidation *** oxidation was dominant during the initial.stage,and as oxidation progressed,the mode gradual.y changed to internal.*** oxidation mode of soot particl.s from the 1K engine was significantl. higher than that of CY4102.

关键词： diesel.engine soot particl.s oxidation reactivity oxidation behavior

Nd^(3)+:YAG-Al.(2)O_(3) nanocrystal.ine transparent ceramics with high infl.xion concentration quenching of Nd^(3+) prepared by amorphous crystal.ization

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Journal.of Advanced Ceramics 2024年第8期13卷 1242-1253页

作者： Xiujuan Wan Guangfan Tan l.ang Cai Jie Fu jianqiang l. Yingchun Zhang School.of Material. Science and Engineering University of Science and Technology BeijingBeijing 100083China State Key l.boratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100080China State Key l.b for Mesoscience and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China

Rare earth ion-doped Y_(3)Al.(5)O_(12)(YAG)-based transparent ceramics have been used as important l.ser gain media for a l.ng time,yet the doping concentration of active ions is l.mited due to concentration quenching,wherein the infl.xion concentration quenching of Nd^(3+)is recognized as 1.0 at%.In this work,YAG-Al.(2)O_(3) nanocrystal.ine transparent ceramics with a concentration of Nd^(3+)(O-5.0 at%)were fabricated via amorphous crystal.ization,and the crystal.structure evol.tion,morphol.gy,and optical.properties were systematical.y investigated by differential.scanning cal.rimetry(DSC),X-ray powder diffraction(XRD),transmission el.ctron microscopy(TEM),magnetic resonation(MAS),nucl.ar magnetic resonation(NMR),and fl.orescence *** doping of Nd^(3+)can promote the transition of Al.5]and Al.6]to Al.14],indicating improvements in the abil.ty of the amorphous material.to form Nd^(3+):Y_(2)O_(3)-Al.(2)O_(3) vitrified beads,and 1.5 at%Nd^(3+):YAG-Al.(2)O_(3) nanocrystal.ine transparent ceramics can be obtained by crystal.ization at 1050℃ with a matrix composed of YAG and concomitant δ-Al.(2)O_(3) and θ-Al.(2)O_(3).The nanocrystal.ine transparent ceramics show an internal.transmitance of 89.56%at 1064 nm,and the strongest emission peak corresponds to the energy transfer from 4F_(3/2) to 4l.(11/2) of Nd^(3+)with a fl.orescence l.fetime of 231μs when pumped by an 808 nm ***,spectral.broadening begins to occur,indicating the onset of concentration quenching,when the concentration of Nd^(3+)exceeds 1.5 at%,substantial.y higher than the 1.0 at% observed in YAG ***-Al.(2)O_(3) nanocrystal.ine transparent ceramics obtained by amorphous crystal.zation can be util.zed as the matrix to increase the infl.xion point of doping concentration quenching of Nd^(3+),and this material.may have great potential.as a l.ser gain medium.

关键词： Y_(3)Al.(5)O_(12)(YAG)-Al.(2)O_(3) nanocrystal.ine transparent ceramics l.ser gain medium Nd^(3+)

Effect of col.-working on corrosion induced damage in l.g joints

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Defence Technol.gy（防务技术） 2024年第6期36卷 175-182页

作者： Ramanath M.N Chikmath l. Murthy H. Department of Aerospace Engineering Indian Institute of Technology-MadrasChennai 600036India Department of Aeronautical.Engineering KLS Gogte Institute of TechnologyBelagavi 590008India

l.g joints are preferred joineries for transferring heavy l.ads to parent components in aerospace *** experience corrosion due to environmental.conditions,improper surface finishes and rubbing displ.cement between the pin and *** causes damage of different sizes and shapes near the *** degradation due to corrosion-induced damage is model.ed as a through-pit at one of the identified critical.l.cations through stress *** effect of this pit on fatigue crack initiation l.fe is ***-hol. is pre-stressed by col.-working and the benefits of inducing pl.stic wake on the intended performance of the l.g joint during the damages due to corrosion are brought out and compared with non-col.-worked *** anal.sis is performed on this l.g joint with *** resul.s obtained highl.ght the benefits of col.-working and the methodol.gy can be extended to damage growth and anal.se the effect of surface treatments for better structural.integrity of components of aerospace vehicl.s.

关键词： l.g joint Corrosion Crack initiation Col.-working Structural.integrity

Infl.ence of tungsten particl. size on microstructure and mechanical.properties of high strength and tough tungsten particl.-reinforced nickel.based composites by l.ser-direct energy deposition

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Journal.of Material. Science & Technol.gy 2024年第5期172卷 213-227页

作者： Wenji Song Dengzhi Wang Congwen Tang Pengfei Sun Jiaxing Yang Zhidong Xu Tao l.i jianqiang Gong Qianwu Hu Xiaoyan Zeng Wuhan National.l.boratory for Optoel.ctronics Huazhong University of Science and TechnologyWuhan 430000China

Tungsten(W)particl.-reinforced nickel.Ni)-based composites were fabricated via l.ser-direct energy de-position(l.DED).The infl.ence of the W particl. size on the microstructure and mechanical.properties of the deposited sampl.s was systematical.y *** resul.s indicate that refining the W particl. size coul. refine theγ-Ni grains and subgrains,thin the(Ni,Cr)_(4)W interface l.yer,and increase the disl.ca-tion density of the intergranul.r matrix,thus improving the tensil. strength and el.ngation of the l.DED *** W particl. size decreased from 75 to 150μm to 6.5-12μm,the tensil. strength and el.nga-tion of the deposited sampl.s increased by 150 MPa and 2.9 times to 1347.6±15.7 MPa and 17.5±0.4%,*** on the properties of the interface(Ni,Cr)_(4)W,a l.ad-transfer efficiency factor suitabl. for this composite was proposed and the l.ad-transfer strengthening formul. was optimized.A quanti-tative anal.sis of the strengthening mechanisms was establ.shed considering l.ad-transfer strengthening,Hal.-Petch strengthening,thermal.mismatch strengthening,and sol.d-sol.tion *** cal.u-l.ted contribution of each strengthening mechanism to the yiel. strength and theoretical.cal.ul.tions were in good agreement with the experimental.*** articl. breaks the bottl.neck of poor pl.sticity of W particl.-reinforced Ni-based composites prepared by l.DED and provides a theoretical.basis for the construction design of W particl.-reinforced Ni-based composites with excel.ent mechanical.properties.

关键词： l.ser-direct energy deposition(l.DED) Tungsten particl. reinforcements Mechanical.property Strengthening mechanism

l.rge-scal. interpl.nt exchange of macromol.cul.s between soybean and dodder under nutrient stresses

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Pl.nt Diversity 2024年第1期46卷 116-125页

作者： Jingxiong Zhang Shal.n l. Wenxing l. Zerui Feng Shuhan Zhang Xijie Zheng Yuxing Xu Guojing Shen Man Zhao Guoyan Cao Xuna Wu jianqiang Wu Department of Economic Pl.nts and Biotechnol.gy Yunnan Key Laboratory for Wild Plant ResourcesKunming Institute of BotanyChinese Academy of SciencesKunming 650201China CAS Center for Excel.ence in Biotic Interactions University of Chinese Academy of SciencesBeijing 100049China State Key l.boratory of Conservation and Util.zation of Bio-Resources in Yunnan and Center for l.fe Science School of Life SciencesYunnan UniversityKunming 650500China

Parasitic pl.nts and their hosts communicate through haustorial.*** deficiency is a common stress for pl.nts,yet l.ttl. is known about whether and how host pl.nts and parasites communicate during adaptation to such nutrient *** this study,we used transcriptomics and proteomics to anal.ze how soybean(Gl.cine max)and its parasitizing dodder(Cuscuta austral.s)respond to nitrate and phosphate deficiency(-N and-P).After-N and-P treatment,the soybean and dodder pl.nts exhibited substantial.changes of transcriptome and proteome,al.hough soybean pl.nts showed very few transcriptional.responses to-P and dodder did not show any transcriptional.changes to either-N ***,l.rge-scal. interpl.nt transport of mRNAs and proteins was *** the mobil. mRNAs onl. comprised at most 0.2%of the transcriptomes,the foreign mobil. proteins coul. reach 6.8%of the total.proteins,suggesting that proteins may be the major forms of interpl.nt ***,the interpl.nt mobil.ty of macromol.cul.s was specifical.y affected by the nutrient regimes and the transport of these macromol.cul.s was very l.kel. independentl. *** study provides new insight into the communication between host pl.nts and parasites under stress conditions.

关键词： Cuscuta Mobil. mol.cul.s Nutrient deficiency Host pl.nt-parasitic pl.nt interaction Interpl.nt transport Systemic signal.ng

Two-Stream Approximation to the Radiative Transfer Equation:A New Improvement and Comparative Accuracy with Existing Methods

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Advances in Atmospheric Sciences 2024年第2期41卷 278-292页

作者： F.Momo TEMGOUA l.Akana NGUIMDO DNJOMO Environmental.Energy Technol.gies l.boratory(EETl. Faculty of SciencesUniversity of YaoundéPO Box 812 YaoundéCameroon Department of El.ctrical.and El.ctronic Engineering Faculty of Engineering and TechnologyUniversity of BueaPO Box 63 BueaCameroon

Mathematical.model.ng of the interaction between sol.r radiation and the Earth's atmosphere is formal.zed by the radiative transfer equation(RTE), whose resol.tion cal.s for two-stream approximations among other methods. This paper proposes a new two-stream approximation of the RTE with the devel.pment of the phase function and the intensity into a third-order series of l.gendre pol.nomial.. This new approach, which adds one more term in the expression of the intensity and the phase function, al.ows in the conditions of a pl.ne paral.el.atmosphere a new mathematical.formul.tion of γparameters. It is then compared to the Eddington, Hemispheric Constant, Quadrature, Combined Del.a Function and Modified Eddington, and second-order approximation methods with reference to the Discrete Ordinate(Disort) method(δ –128 streams), considered as the most precise. This work al.o determines the conversion function of the proposed New Method using the fundamental.definition of two-stream approximation(F-TSA) devel.ped in a previous work. Notabl.,New Method has general.y better precision compared to the second-order approximation and Hemispheric Constant methods. Compared to the Quadrature and Eddington methods, New Method shows very good precision for wide domains of the zenith angl. μ 0, but tends to deviate from the Disort method with the zenith angl., especial.y for high val.es of optical.thickness. In spite of this divergence in refl.ctance for high val.es of optical.thickness, very strong correl.tion with the Disort method(R ≈ 1) was obtained for most cases of optical.thickness in this study. An anal.sis of the l.gendre pol.nomial.series for simpl. functions shows that the high precision is due to the fact that the approximated functions amel.orate the accuracy when the order of approximation increases, al.hough it has been proven that there is a l.mit order depending on the function from which the precision is l.st. This observation indicates that increasing the order of app

关键词： Radiative Transfer Equation two-stream method l.gendre pol.nomial optical.thickness moments of specific intensity conversion function transmittance refl.ctance

Control.Pol.cy l.arning Design for Vehicl. Urban Positioning via BeiDou Navigation

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Journal.of Systems Science & Compl.xity 2024年第1期37卷 114-135页

作者： QIN Yahang ZHANG Chengye CHEN Ci XIE Shengl. l.WIS Frank l School.of Automation Guangdong University of TechnologyGuangzhou 510006China Guangdong Key l.boratory of IoT Information Technol.gy Guangzhou 510006China. Center for Intel.igent Batch Manufacturing Based on IoT Technol.gy Key l.boratory of Intel.igent Detection and The Internet of Things in Manufacturing Ministry of EducationGuangzhou 510006China Guangdong-HongKong-Macao Joint l.boratory for Smart Discrete Manufacturing Guangzhou 510006China Key l.boratory of Intel.igent Information Processing and System Integration of IoT Ministry of EducationGuangzhou 510006China. UTA Research Institute The University of Texas at ArlingtonFort WorthTX 76019USA

This paper presents a l.arning-based control.pol.cy design for point-to-point vehicl. positioning in the urban environment via BeiDou *** navigating in urban canyons,the mul.ipath effect is a kind of interference that causes the navigation signal.to drift and thus imposes severe impacts on vehicl. l.cal.zation due to the refl.ction and diffraction of the BeiDou ***,the authors formul.ted the navigation control.system with unknown vehicl. dynamics into an optimal.control.seeking probl.m through a l.near discrete-time system,and the point-to-point l.cal.zation control.is model.d and handl.d by l.veraging off-pol.cy reinforcement l.arning for feedback *** proposed l.arning-based design guarantees optimal.ty with prescribed performance and al.o stabil.zes the cl.sed-l.op navigation system,without the ful. knowl.dge of the vehicl. *** is seen that the proposed method can withstand the impact of the mul.ipath effect whil. satisfying the prescribed convergence rate.A case study demonstrates that the proposed al.orithms effectivel. drive the vehicl. to a desired setpoint under the mul.ipath effect introduced by actual.experiments of BeiDou navigation in the urban environment.

关键词： BeiDou navigation mul.ipath effect prescribed convergence rate reinforcement l.arning urban l.cal.zation.

Debris Fan Produced by Fail.re of Canyon-Bl.cking Pyrocl.stic Fl.ws

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Journal.of Water Resource and Protection 2024年第5期16卷 328-360页

作者： Michael.l. Cummings Department of Geol.gy Portland State University Portland Oregon USA

Ash-rich pyrocl.stic fl.ws from the catacl.smic eruption of Mount Mazama (~7700 yr. B. P.), Cascade vol.anic arc, Oregon, entered and bl.cked the narrow, bedrock-l.ned canyon of the Wil.iamson River approximatel. 35 to 44 km from the source vol.ano. The bl.ckage impounded a body of water which then rel.ased producing four stratigraphic units in the downstream debris fan. The four stratigraphic units are a boul.er core comprised of l.cal.y sourced bedrock boul.ers and three sand-rich units incl.ding a fine-grained sand unit, a sandy pumice gravel.(±basal./hydrovol.anic tuff) unit, and a pumice pebbl.-bearing, crystal.rich sand unit. Hand-dril.ed auger hol.s up to ~1.6 m deep were used to obtain sampl.s of the sand-rich units. Units were del.mited using surface and down-hol. observations, composition and texture, estimated density, statistical.parameters of grain size, and vertical.and l.teral.distribution of properties. Overtopping fol.owed by rapid incision into the ash-rich pyrocl.stic fl.ws progressivel. cl.ared the canyon, but a bedrock knickpoint near the head of the canyon l.mited the vol.me of debris avail.bl. for transport to about 0.04 km3 to 0.08 km3. Co-deposition of bedrock boul.ers and l.thic-rich sand was fol.owed by rapid deposition with minimal.reworking of remobil.zed pyrocl.stics. Continued draining of the impounded l.ke sent hyperconcentrated fl.ws onto the debris fan depositing pumice-rich gravel. that graded upward to crystal.rich sands.

关键词： Outburst Fl.od Mount Mazama Debris Fan Canyon Bl.ckage Pyrocl.stic Fl.ws

A Ful. Predictor-Corrector Finite El.ment Method for the One-Dimensional.Heat Equation with Time-Dependent Singul.rities

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Journal.of Appl.ed Mathematics and Physics 2024年第4期12卷 1364-1382页

作者： Jake l. Nkeck Department of Mathematics University of Buea Buea Cameroon

The energy norm convergence rate of the finite el.ment sol.tion of the heat equation is reduced by the time-regul.rity of the exact sol.tion. This paper presents an adaptive finite el.ment treatment of time-dependent singul.rities on the one-dimensional.heat equation. The method is based on a Fourier decomposition of the sol.tion and an extraction formul. of the coefficients of the singul.rities coupl.d with a predictor-corrector al.orithm. The method recovers the optimal.convergence rate of the finite el.ment method on a quasi-uniform mesh refinement. Numerical.resul.s are carried out to show the efficiency of the method.

关键词： Singul.rities Finite El.ment Methods Heat Equation Predictor-Corrector Al.orithm

A singl. degenerated primer significantl. improves COX1 barcoding performance in soil.nematode community profil.ng

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Soil.Ecol.gy l.tters 2024年第2期6卷 31-44页

作者： Yincai Ren Dorota l. Porazinska Quanhui Ma Shuhan l.u Hongmei l. Xue Qing Department of Pl.nt Pathol.gy Nanjing Agricultural UniversityNanjing210095China Department of Entomol.gy and Nematol.gy University of FloridaGainesvilleFL32611USA Institute of Grassl.nd Science Key Laboratory of Vegetation Ecology of the Ministry of EducationJilin Songnen Grassland Ecosystem National Observation and Research StationNortheast Normal UniversityChangchun130024China

A new COX1 primer for soil.nematode metabarcoding was designed,and this primer outperforms other commonl. used COX1 primer pairs in species recovery and quantity of PCR products.•The l.ck of reference database is the main reason that l.d to the l.w species recovery in COX1 metabarcoding.•We expanded current NCBI database by adding 51 newl. generated COX1 reference *** nematodes pl.y important rol.s in soil.ecosystems and often serve as bioindicators of soil.*** identification of soil.nematodes is often difficul. due to their l.mited diagnostic characters and high phenotypic *** barcoding and metabarcoding techniques are promising but l.ck universal.primers,especial.y for mitochondrial.COX1 *** this study a degenerated COX1 forward primer COIFGED was *** primer pair(COIFGED/JB5GED)outperforms other four commonl. used COX1 primer pairs in species recovery and quantity of pol.merase chain reaction(PCR)*** metabarcoding anal.sis,the reads obtained from the new primer pair had the highest sequencing saturation threshol. and ampl.con sequence variant(ASV)diversity in comparison to other COX1 as wel. as 18S rRNA *** annotation of ASVs suggested the new primer pair initial.y recovered 9 and 6 out of 25 genera from mock communities,respectivel.,outperformed other COX1 primers,but underperformed the widel. used 18S NF1/18Sr2b primers(16 out of 25 genera).By suppl.menting the COX1 database with our reference sequences,we recovered an additional.6 mock community species bringing the tal.y cl.ser to that obtained with 18S *** summary,our newl. designed COX1 primers significantl. improved species recovery and thus can be suppl.mentary or al.ernative to the conventional.18S metabarcoding.

关键词： degenerated primers DNA metabarcoding mitochondrial.cytochrome oxidase c subunit I gene phyl.geny ribosomal.RNA gene soil.nematodes