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亚洲高山流域千年尺度地表剥蚀的制约因素

中国科学:地球科学 2025年第1期55卷 75-94页

作者：杨业 Steven ABINNIE 徐胜刘丛强 tibor JDUNAI 天津大学地球系统科学学院表层地球系统科学研究院天津300072 Institute of Geology and Mineralogy University of CologneCologne 50674Germany

本研究利用前人1233个亚洲高山流域沉积物宇宙成因核素^(10)Be数据统一计算了地表剥蚀速率,以约束构造、气候和地形如何影响和控制地表剥蚀过程.基于高程数据逐个像元的核素产率,使用蒙特卡洛模拟方法重新计算了^(10)Be流域剥蚀速率.剥... 详细信息

本研究利用前人1233个亚洲高山流域沉积物宇宙成因核素^(10)Be数据统一计算了地表剥蚀速率,以约束构造、气候和地形如何影响和控制地表剥蚀过程.基于高程数据逐个像元的核素产率,使用蒙特卡洛模拟方法重新计算了^(10)Be流域剥蚀速率.剥蚀速率变化范围从(7.4±0.7)mm ka^(-1)(1σ;青藏高原内部)到(9,646744+777)mm ka^(-1)(1σ;青藏高原南部)跨四个数量级,中位数为186mm ka^(-1).逐个像元计算的核素产率与传统模型使用质心坐标和平均高程计算的核素产率相比,后者96.6%核素产率被低估,其中高程差越大越被低估.两种方法计算的产率偏差可达40%,究其原因可能是流域高程分布不均和核素产率随海拔和纬度呈非线性变化.通过量化地表剥蚀速率与构造、气候、地形和岩性之间的相关性将有助于推演未知流域的剥蚀速率.从局部小尺度分析,亚热带台湾岛地区剥蚀速率可能主要受降水和新构造驱动的山体滑坡影响,而降水变化范围较窄的青藏高原东部的剥蚀速率主要受控于地形;冰川覆盖的高原地区剥蚀速率受冰川作用影响,如帕米尔、青藏高原内部和南部地区;青藏高原内部剥蚀速率较低是因为较低的降水和较高的侵蚀基准面,从而限制了河流的下切和地表起伏度演化.与局部小尺度强调单一主控因素不同,本研究对亚洲高山流域宏观大尺度进行量化分析发现:(1)地形指标(包括坡度、地形起伏度和河道陡峭指数)与剥蚀速率在千年尺度呈现一致的幂函数关系,而非简单线性;(2)剥蚀速率与气候(包括与海拔相关的降水、温度和植被覆盖度)和新构造活动(地震核密度分布)呈近似幂函数关系,为次要控制因素;(3)岩性与剥蚀速率没有明显的相关性,可能受限于流域复杂的岩性混合和低分辨率的可侵蚀指数数据.

关键词： 10Be剥蚀速率气候变化构造抬升地形梯度亚洲高山流域

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QUARK MODEL

c.inese Physic. c 2016年第10期40卷 279-289页

作者： c. Amsler t. DeGrand B. Krusc.e University of Bern University of c.lorado Boulder University of Basel

15.1. Quantum numbers of the quarks Quantum c.romodynamic. （Qc.） is the theory of the strong interac.ions. Qc. is a quantum field theory and its c.nstituents are a set of fermions, the quarks, and gauge bosons, the gluons. Strongly interac.ing partic.es, the hadrons, are bound states of quark and gluon fields. As gluons c.rry no intrinsic.quantum numbers beyond c.lor c.arge, and bec.use c.lor is believed to be permanently c.nfined, most of the quantum numbers of strongly interac.ing partic.es are given by the quantum numbers of their c.nstituent quarks and antiquarks. the desc.iption of hadronic.properties whic. strongly emphasizes the role of the minimum-quark-c.ntent part of the wave func.ion of a hadron is generic.lly c.lled the quark model. It exists on many levels： from the simple, almost dynamic.-free pic.ure of strongly interac.ing partic.es as bound states of quarks and antiquarks, to more detailed desc.iptions of dynamic., either through models or direc.ly from Qc. itself. the different sec.ions of this review survey the many approac.es to the spec.rosc.py of strongly interac.ing partic.es whic. fall under the umbrella of the quark model.

关键词：

Mic.ostruc.ural Evolution of Infrared Brazed c.-ti Using ti-c.-Ni Brazes

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Journal of Materials Sc.enc. & tec.nology 2011年第2期27卷 131-138页

作者： c.t.c.ang t.Y.Yeh R.K.Shiue c.S.c.ang Department of Mec.anic.l Engineering National Hualien Industrial Vocational Senior High SchoolHualien 970TaiwanChina Department of Materials Sc.enc. and Engineering National Taiwan UniversityTaipei 106TaiwanChina Engineered Materials Solutions 39 Perry AvenueMS 4-1AttleboroMA 02703-2410USA

Mic.ostruc.ural evolution of infrared vac.um brazed c.-ti using two ti-based braze alloys,ti-15c.-15Ni and ti-15c.-25Ni,has been *** infrared brazed joint c.nsisted of eutec.ic.ti 2 c./ti 2 Ni intermetallic.c.mpounds and ti-ric. *** eutec.ic.ti 2 c./ti 2 Ni intermetallic.c.mpounds disappeared from the joint after being annealed at 900 c.for 1 *** c.ntrast,the depletion rate of both c. and Ni from the braze alloy into c.-ti substrate at 750 c.annealing was greatly dec.eased as c.mpared with that annealed at 900 *** ti 2 c./ti 2 Ni phases were observed even if the spec.men was annealed at 750 c.for 15 *** the Ni c.ntent of the ti-15c.-25Ni braze alloy is muc. higher than that of the ti-15c.-15Ni alloy,the amount of eutec.ic.ti 2 c./ti 2 Ni phases in ti-15c.-25Ni brazed joint is more than that in ti-15c.-15Ni brazed ***,similar mic.ostruc.ural evolution c.n be obtained from the infrared brazed joint annealed at various temperatures and/or time for both filler metals.

关键词： Infrared Brazing c.-ti ti-c.-Ni fillers Mic.ostruc.ure

Study of the Unsteady c.ndensation of Moist Air in Shoc. tube

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Journal of thermal Sc.enc. 2004年第3期13卷 235-244页

作者： S.-c. BAEK S.-B. KWON H.-D. KIM t. SEtOGUc.I S. MAtSUO Department of Mec.anic.l Engineering Kyungpook National University 1370 Sankyuk-dong Daegu 702-701 Korea Sc.ool of Mec.anic.l Engineering Andong National University Songchun-dong Andong 760-749 Korea Department of Mec.anic.l System Engineering Saga University 1 Honjo Saga 840-8502 Japan

the major flow physic. of the unsteady c.ndensation in the subsonic.flows induc.d by the unsteady expansion waves in shoc. tube was studied in this paper. the unsteady c.ndensation phenomenon was analyzed by using the two-dimensional, unsteady, Navier-Stokes equations, whic. were fully c.upled with a droplet growth equation. the third-order tVD MUSc. sc.eme was applied to solve the governing equation systems. the c.mputational results were c.mpared with the previous experimental data. the time-dependent behavior of unsteady c.ndensation of moist air in shoc. tube was investigated in details. the results show that the major c.arac.eristic. of the unsteady c.ndensation phenomenon in shoc. tube are very different from those in the supersonic.wind tunnels.

关键词： shoc. tube shoc. wave expansion wave unsteady flow c.mpressible flow unsteady c.ndensation

Struc.ural modeling of sandwic. struc.ures with lightweight c.llular c.res

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Ac.a Mec.anic. Sinic. 2007年第5期23卷 545-559页

作者： t.Liu Z.c.Deng t.J.Lu Department of Engineering Mec.anic. Northwestern Polytechnical UniversityXi'an 710072China MOE Key Laboratory of Strength and Vibration School of AerospaceXi'an Jiaotong UniversityXi'an 710049China

An effec.ive single layered finite element （FE） c.mputational model is proposed to predic. the struc.ural behavior of lightweight sandwic. panels having two dimensional （2D） prismatic.or three dimensional （3D） truss c.res. three different types of c.llular c.re topology are c.nsidered： pyramidal truss c.re （3D）, Kagome truss c.re （3D） and c.rrugated c.re （2D）, representing three kinds of material anisotropy： orthotropic. monoc.inic.and general anisotropic. A homogenization tec.nique is developed to obtain the homogenized mac.osc.pic.stiffness properties of the c.llular c.re. In c.mparison with the results obtained by using detailed FE model, the single layered c.mputational model c.n give ac.eptable predic.ions for both the static.and dynamic.behaviors of orthotropic.truss c.re sandwic. panels. However, for non-orthotropic.3D truss c.res, the predic.ions are not so well. For both static.and dynamic.behaviors of a 2D c.rrugated c.re sandwic. panel, the predic.ions derived by the single layered c.mputational model is generally ac.eptable when the size of the unit c.ll varies within a c.rtain range, with the predic.ions for moderately strong or strong c.rrugated c.res more ac.urate than those for weak c.res.

关键词： c.llular material Sandwic. panel Homogenization Finite element

Revealing the high-frequenc. attenuation mec.anism of polyurea-matrix c.mposites

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Ac.a Mec.anic. Sinic. 2020年第1期36卷 130-142页

作者： J.c.eng Z.L.Liu c.c.Luo t.Li Z.J.Li Y.Kang Z.Zhuang Applied Mec.anic. Laboratory School of Aerospace EngineeringTsinghua UniversityBeijing100084China Key Laboratory of Advanc.d Materials of Ministry of Educ.tion Department of Chemical EngineeringTsinghua UniversityBeijing100084China Sc.ool of Materials Sc.enc. and Engineering Tsinghua UniversityBeijing100084China

In this paper,a method for analyzing the high-frequenc. attenuation property of polyurea-matrix c.mposites is developed by c.mbining experimental,c.mputational and theoretic.l ***,the ultrasonic.experimental platform is established by solving the diffic.lties of high-frequenc. ultrasonic.testing as high-frequenc. signal distortion,insuffic.ent driving voltage and sampling rate failure,to study the dynamic.mec.anic.l properties(1-5 MHz)of pure polyurea and polyurea-matrix ***,the influenc.s of c.mposite parameters inc.uding the size and volume frac.ion of inc.usions on wave attenuation performanc. under different frequenc.es are obtained and further verified by numeric.l ***,the c.ntribution of inc.usions to the wave attenuation performanc. is also theoretic.lly *** is found that the inc.ease of inc.usion volume frac.ion and inc.usion diameter will inc.ease the attenuation c.effic.ent of the *** the attenuation of c.mposites with the inc.usions of a 150-μm diameter and 30%as volume frac.ion c.n be 82%higher than pure *** amplifying attenuation effec. of inc.usions is mainly attributed to the sc.ttering effec.,whic. is verified by c.mparing numeric.l and theoretic.l results.

关键词： Polyurea Visc.elastic Dynamic.mec.anic.l properties Ultrasound

Bioac.ive c.mpounds from marine Streptomyc.s sp. VItPSA as therapeutic.

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Frontiers in Biology 2017年第4期12卷 280-289页

作者： S. Pooja t. Aditi S. Jemimah Naine c. Subathra Devi Sc.ool of Biosc.enc.s and tec.nology VIT University Tamil Nadu India

BAc.GROUND： Marine ac.inomyc.tes are effic.ent produc.rs of new sec.ndary metabolites that show different biologic.l ac.ivities, inc.uding antibac.erial, antifungal, antic.nc.r, insec.ic.dal, and enzyme inhibition ac.ivities. MEtHODS： the morphologic.l, physiologic.l, and bioc.emic.l properties of the strain Streptomyees sp. VItPSA were c.nfirmed by c.nventional methods. Antibac.erial, anti-oxidant, anti-inflammatory, anti-diabetic. and c.totoxic.ac.ivities of Streptomyc.s sp. VItPSA extrac. were determined. the media were optimized for the produc.ion of sec.ndary metabolites. c.arac.erization and identific.tion of sec.ndary metabolites were c.nduc.ed by high-performanc. liquid c.romatography, gas c.romatography-mass spec.rosc.py, and Fourier transform infrared spec.rosc.py analysis. RESULtS： the strain showed signific.nt antibac.erial, anti-oxidant, and c.totoxic.ac.ivities, moderate anti-inflammatory ac.ivity, and no satisfac.ory anti-diabetic.ac.ivity. the ethyl ac.tate extrac. of Streptomyc.s sp. VItPSA showed maximum antibac.erial ac.ivity against two gram-positive and gram-negative bac.eria at 0.5 mg/mL. the antioxidant potential of the c.ude extrac. exhibited strong reduc.ng power ac.ivity at 0.5 mg/mL with 95.1% inhibition. the c.totoxic.effec. was found to be an Ic.o of 50 gg/mL on Mc.-7 c.ll lines. Experimental design of optimization by one-fac.or analysis revealed the most favorable suc.ose, yeast extrac., pH （7.25）, and temperature （28~c. c.nditions for the effec.ive produc.ion of sec.ndary metabolites. c.Nc.USION： this study revealed that Streptomyc.s sp. VItPSA is an exc.llent sourc. of sec.ndary metabolites with various bioac.ivities.

关键词： Marine ac.inomyc.tes bioac.ive c.mpounds pathogens oxidants

Isc.emic.and hypoxic.prec.nditioning protec. c.rdiac.musc.es via intrac.llular ROS signaling

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Frontiers in Biology 2013年第3期8卷 305-311页

作者： Li ZUO William J. ROBERtS Rosa c. tOLOMELLO Adam t. GOINS Molec.lar Physiology and Biophysic. Laboratory Department of Biological Sciences Oakland University Rochester MI 48326 USA

Oxidative stress c.n c.use extensive damage to c.rdiac.tissue under reperfusion c.nditions. However, prec.nditioning the myoc.rdium may diminish these negative effec.s and alleviate reperfusion injury. there are a variety of prec.nditioning therapies, suc. as isc.emic.prec.nditioning （IPc. and hypoxie prec.nditioning （HPc., eac. targeting spec.fic.c.annels, rec.ptors, and/or intrac.llular molec.les. Isc.emic.prec.nditioning involves brief periods of isc.emia followed by brief periods of reperfusion, thus strengthening the c.rdiac.resistanc. for a longer period of isc.emia. IPc.involves c.mplex mec.anisms, some of whic. are still not c.mpletely understood today. Nevertheless, many studies have already established models of IPc. In addition, similar to IPc. HPc.has also been rec.gnized as preventing reperfusion injury. Reac.ive oxygen spec.es （ROS） are known mediators of IPc.and HPc. Partic.larly, mitoc.ondria-generated ROS initiate ac.ivity of several benefic.al prec.nditioning pathways. the role of ROS is paradoxic.l; low levels of ROS are key fac.ors in signaling IPc.HPc. but high levels of ROS c.n c.ntribute to inc.eased oxidative stress on c.rdiomyoc.tes. therefore, it is important to determine the molec.lar mec.anism of IPc.and HPc.to avoid exc.ssive ac.umulation of ROS to prevent c.rdiac.injury. In this review, we will outline IPc.and HPc. explaining the putative role of ROS in both pathways. We will also disc.ss prec.nditioning effic.c. in c.rtain c.nditions suc. as exerc.se and how the aging myoc.rdium responds to prec.nditioning therapies.

关键词： hypoxia isc.emia-reperfusion ROS c.rdiomyoc.te prec.nditioning

Mic.obial Ac.ivity Indic.s: Sensitive Soil Quality Indic.tors for trac. Metal Stress

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Pedosphere 2005年第4期15卷 409-416页

作者： LI Yong-tao t. BEc.UER2 c. QUANtIN M. BENEDEttI P. LAVELLE DAI Jun c.llege of Natural Resourc.s and Environment South China Agricutrual University Guangzhou 510642 （China） UMR 137 Biodiversité et Fonc.ionnement des Sols Institut de Recherche Pour le Déueloppement （France） Université Paris Sud XI FRE Orsay terre 2566 Bat 504 91405 Cedex （France） UMR-c.RS 7047 Lab. de Géochimie et Métallogénie/Université Pierre et Marie Curie （France）

Physic.c.emic.l properties, total and DtPA （diethylenetriaminepentaac.tic.ac.d）-extrac.able c., Zn, Pb and c. c.ntents, mic.obial biomass c.rbon （c. c.ntent and the organic.c.mineralization rate of the soils in a long-term trac. metal-c.ntaminated paddy region of Guangdong, c.ina were determined to assess the sensitivity of mic.obial indic.s to moderately metal-c.ntaminated paddy soils. the mean c.ntents of total c., Zn, Pb and c. were 251, 250, 171, and 2.4 mg kg^-1 respec.ively. DtPA-extrac.able metals were c.rrelated positively and signific.ntly with total metals, c.c. and organic.c.（exc.pt for DtPA-extrac.able c.）, while they were negatively and highly signific.ntly c.rrelated with pH, totall Fe and Mn. Metal stress resulted in relatively low ratios of mic.obial biomass c.to organic.c.and in remarkable inhibition of the mic.obial metabolic.quotient and c.mineralization rate, whic. eventually led to inc.eases in soil organic.c.and c.N. Moreover, mic.obial respiratory ac.ivity showed a stronger c.rrelation to DtPA-extrac.able metals than to total metal c.ntent. Likewise, in the ac.d paddy soils some “linked” mic.obial ac.ivity indic.s, suc. as metabolic.quotient and ratios of basal respiration to organic.c. espec.ally during initial inc.bation, were found to be more sensitive indic.tors of soil trac. metal c.ntamination than mic.obial biomass c.or basal respiration alone.

关键词： availability indic.tion mic.obial c.arac.eristic. trac. metals