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Althoughthedesignofcomputingschemeinthenumericalweatherpredictionismainlytoimprovethespacialdifference,theresearchforimprovingthetimedifferenceschemehasseenapparentprogresses[1~5].Itisconfirmedthattheretrospectivetimeintegralschemeadoptedinaspectrummodel,whichutilizesmultitimehistoricaldata,improvestheaccuracyofthenumericalweatherprediction[6,7].Inthisarticle,weapplytheretrospectivetimeintegralschemetoasimpledifferencemodel,performnumericalexperimentsandpresentacomparisonanalysis.1 Principle…  相似文献   

3.
IntroductionAlkalinephosphatase(AP)hasbeenthoughttobeimportantintheprocessofbiocalcification[1].APwasthefirstenzymeassociatedwithcalcificationactivityintissuesandremainsasthebestcharacterizedenzymeinthecalcificationprocess.Yet,importantquestionsabouttheroleofthisproteininbiocalcificationremainunanswered,anditcontinuestodrawfocusedattentionincalcifiedtissueinvestigations[2].APpromoteshydrolysisofphosphatecontainingsubstrates[1],producesorthophosphateandcausesariseininorganicphosphateandtherem…  相似文献   

4.
IntroductionThemeasurementandevaluationdependentuponhumanexperimentorsenseorganiscalled“sensoryevaluation”[1].Generally,sensoryevaluationisappliedtoestimateproductsorotherthings,suchasoutstandingachievementofenterprise,qualityofcommodities,examinationofexcellentthesis,faultdiagnosis[2],buildingandcondominiuminrelationtoamenityinlivingenvironment[1],designofcontrolsystem[3].Techniquesbasedonclassicalstatisticprinciplesandfactorialanalysisareoftenusedinevaluation.Recently,sensoryevaluationhasb…  相似文献   

5.
Carbondioxide(CO2),akeygreenhousegas,con-tributesgreatlytoglobalwarming.TheatmosphericCO2concentrationhasincreasedby31%since1750[1].Theincreaseratewas3.2±0.1Pga-1(1Pg=1015g)inthe1990sandthecurrentincreaserateisunprecedentedoverthepast20000years[1].TheatmosphericCO2contentismostlydependentonthenetexchangeofCO2withincarbonpoolsinvolvedinthecarboncycleprocesses.InvestigationoftheprocessesandmechanismsofCO2exchangebetweenterrestrialecosystemandtheatmos-pherehasbeenbecomingoneofthehotspotswit…  相似文献   

6.
Intertidalseaweedsusuallyexperiencehoursto daysofdesiccationduringemersionbeforebeingim mersedagainintidecycles[1].Tosomespeciesofsea weedsthedesiccationimposednegativeeffectson photosynthesisandrespiration[2—6],itcouldalsoen hancethenetphotosynthesisofmostdetectedsea weedsattheinitialphaseofthewaterlosingpro cess[5,7—12].However,littlehasbeendocumentedon therelationshipofphotosyntheticrecoverywithwater retainingability.Desiccation resistantperformancesofintertidal seaweedswereconsideredtobe…  相似文献   

7.
Fish Sauce Fermentation with Silver Carp or Offal of Surimi Processing   总被引:1,自引:0,他引:1  
IntroductionFishsauceisakindofcondimentsprocessedfromfish.Inthecourseoffermentationprocess,fishproteininrawmaterialsisdegradedbybothendogenousandextraneousproteinasesexcretedbymicrobeinfish[1].Beinganutritiousanddeliciouscondiment,fishsauceisenrichedwithaminoacids,organicacids,calcium,ironandotherminerals.InthelonghistoryinChina,theearliestrecordofprocessingoffishsaucecanbefoundinthebookof“Zhouli”,publishedinthethirdcentury[2].Atthemomenttheregionswherefishsauceisprocessedandcommonlyconsum…  相似文献   

8.
Plantheightisoneofimportantagronomictraitsinmaizebreeding.Inthepastfewyears,toincreasetheplantingdensityandpreventplantsfromlodging,studiesonthegeneticmechanismofplantheightweregivengreatattentionto.Sincethe1990s,molecularmarkershaveprovidedapowerfultooltostudythetraitofplantheightatthemolecularlevel[1—3].Butmostofresearchforplantheightonlyfocusedondataatmaturestage.Tillnow,about70genesorQTLshavebeenlocated[4].Moreover,somegeneshavebeenevencloned[5—7].Duringthevege-tativegrowthperiod,plant…  相似文献   

9.
0Introduction Highconcentrationoffluorideoccurrednaturallyingroundwaterthroughoutmanypartsoftheworldduetoitsnaturalpresenceintheearthcrustordischargebyagri cultureorindustryactivities.Long termingestionofhighflu oridedrinkingwatercausedserioustoxiceffectsandaffectedmanypeoplearoundworld.In1993,25millionpeoplein15ofIndia’s32stateswereidentifiedasendemicforfluorosis[1].InMexico,5millionpeople(about6%ofthepopulation)wereaffectedbyfluorideingroundwater[2].Fluorosiswas alsothreateningsomepartsof…  相似文献   

10.
Hydrogeneticferromanganesecrusts(Fe Mn crustshereafter),areinorganiccolloidprecipitatesfromseawater,whicharebelievedtohaverecorded theevolutionofelementalandisotopiccompositionsof seawaterovertime[1—7].Studiesontraceelements andisotopeshavebroughtmoreinsightsthanstudies onironandmanganesecontents.TheMn/Feratio hasbeenconsideredtoreflectwaterdepth,deep wa teroxygenation[8,9],andhasalsobeensuggestedasa reliablecriterionfordistinguishingdifferentgenetic typesofferromanganesedeposits[10].Apossi…  相似文献   

11.
Simultaneous in-situ determination of U-Pb ages and 20 trace elements of three international zircon standards (91500, GJ1 and TEMORA 1) and one laboratory zircon standard (SK10-2) separated from Cenozoic fine-grained gabbro was carried out on quadrupole ICP-MS equipped with 193 nm excimer laser in 20 μm spot size. The weighted mean ^206Pb/^238U ages of 91500, GJ1 and TEMORA 1 are 1064.4±4.8 Ma (2σ), 603.2±2.4 Ma (2σ) and 418.2±2.4 Ma (2σ), respectively. The relative standard deviations (RSDs) of ^206Pb/^238U ages (2σ) are less than 2.2% for single measurements and 0.6% for weighted means. The obtained weighted mean ^206Pb/^238U ages of three standard zircons agree with the recommended values within 2σrerror. The weighted mean ^206Pb/^238U age of SK10-2 is 31.42=0.25 Ma (2σ) and the RSDs of ^206Pb/^238U ages (2σ) are between 2.4% and 5.7% for single measurements and less than 0.8% for weighted mean. The obtained weighted mean ^206Pb/^238U age is in good agreement with the age obtained by Yuan (2004). Trace element concentrations of NIST612 and NIST614 obtained under the same LA-ICP-MS operating conditions agree with the recommended values within analytical error. The results indicate that it is possible to measure U-Pb age and trace elements simultaneously by LA-ICP-MS in a small spot size of 20μm.  相似文献   

12.
This note reports the SHRIMP U-Pb data of zircons from the Caledonian Xiongdian eclogite, western Dabie Mountains. Zircons from the rock occur mainly in garnet and other metamorphic minerals with sharp boundaries and exhibit textures growing under metamorphic conditions. Analyses of 7 grains give 206Pb/238U ages ranging from 335 to 424 Ma, showing a certain degree of radiogenic lead loss. This suggests a minimum age of (424±5) Ma for the metamorphic zircons, as well as the high-pressure metamorphic event. The outer peripheral zone of a zircon gives 206Pb/238U age of about 300 Ma. Combined with Sm-Nd, 40Ar-39Ar, U-Pb and 207Pb/206Pb ages, the peak metamorphism of the Xiongdian eclogite is documented between 424—480 Ma.  相似文献   

13.
熬油沟蛇绿岩是北祁连造山带西段最具代表性的蛇绿岩残片之一。运用SHRIMPⅡ锆石U-Pb法, 对北祁连造山带西段的熬油沟和二只哈拉达坂两地出露的细粒辉长岩和粒玄岩进行了精确同位素测年。采自熬油沟剖面的细粒辉长岩样品 206Pb/238U年龄数据分布在一个很小的范围(490~508 Ma), 其加权平均年龄为501±4 Ma (MSWD=1.09); 采自二只哈拉剖面的粒玄岩样品年龄值稍小, 206Pb/238U加权平均年龄为495±4 Ma (MSWD=0.98)。结合详细的野外调查、矿物化学和地球化学研究, 认为熬油沟?二只哈拉达坂蛇绿岩构造破坏严重, 其中基性岩浆岩代表早?中寒武世的北祁连洋壳。与新元古界朱龙关群碳酸盐岩和砂泥岩整合产出 的玄武岩不能作为蛇绿岩的喷出岩系列, 而有可能是震旦纪的大陆溢流玄武岩, 代表新元古代全球Rodinia大陆裂解的岩浆产物。  相似文献   

14.
Different types of UHP metamorphic rocks havebeen recently discovered in the Altyn Tagh[1—4], the north-ern margin of Qadam Basin[5—7], the southwestern Tian-shan Mountains[8,9] and the northern Qinling Moun-tains[10,11] in Central and Western China. And these areashave attracted focus attention of geologists at home andabroad to the studying of UHP metamorphism and conti-nental deep subduction. However, as newly discoveredUHP metamorphic terranes, some questions have beenarisen abou…  相似文献   

15.
In addition to the wide spread peraluminous granites, some alkaline or alkali-rich intrusive rocks were recently observed in the Wuyi Mountains. The Yangfang aegiriteaugite syenites in the Wuyi Mountains are strongly enriched in light rare earth elements (LREE), K, Ba, Ga, Zr and Y. What is more, differentiations of REE are obvious. In addition, the Yangfang aegiriteaugite syenites have also some characteristics similar to A-type granite. Zircons are selected from the Yangfang aegiriteaugite syenites for Sensitive High-Resolution Ion Microprobe (SHRIMP-Ⅱ) U-Pb geochronology study. 15 analyses give concordant 206Pb/238U ages in a narrow range of 233—249 Ma, which correspond to a single age population with a weighted mean 206Pb/238U age of 242 4 Ma, which records the crystallization time of the aegiriteaugite syenites. It is suggested that: (1) there were early Triassic peralkaline intrusive rocks in South China; (2) the early Indosinian extension event was probably active in local area, South China. This discovery provides a new insight for farther understanding of 揑ndosinian orogeny in South China.  相似文献   

16.
In situ U-Pb dating of titanite by LA-ICPMS   总被引:4,自引:0,他引:4  
Titanite is an ideal mineral for U-Pb isotopic dating because of its relatively high U,Th and Pb contents.Here,we developed a technique for U-Pb dating of titanite using the 193 nm ArF laser-ablation system and Agilent 7500a Q-ICP-MS.Standards of titanite (BLR-1 and OLT-1) and zircon (91500 and GJ-1) were dated using single spot and line raster scan analytical methods.To check the matrix effect,titanite (BLR-1) and zircon (91500) standards were analyzed as the external standards.The weighted mean 206 Pb/238 U ages of OLT-1 titanite are 1015±5 Ma (2,n=24) and 1017±6 Ma (2,n=24) by single spot and line raster scan analyses,respectively,using BLR-1 titanite as the external standard.These ages are consistent with its reference age of about 1014 Ma.However,using 91500 zircon as the external standard,the weighted mean 206 Pb/238 U ages are 917±4 Ma (2,n=24) and 927±5 Ma (2,n=24) for BLR-1 titanite,and 891±4 Ma (2,n=24) and 901±5 Ma (2,n=24) for OLT-1 titanite by single spot and line raster scan analyses,respectively.It is evident that these ages are ~12% younger than their reference values.Our results reveal that significant matrix effect does exist between different kinds of minerals during LA-ICPMS U-Pb age determination,whereas it is insignificant between same minerals.Therefore,same mineral must be used as the external standard for fractionation corrections during in situ LA-ICPMS U-Pb age analysis.In addition,we determined U-Pb ages for titanites from the Early Cretaceous Fangshan pluton,which indicates a rapid cooling history of this pluton.  相似文献   

17.
通过1∶5万朱拉比拉河等图幅区域地质调查工作,在伊春地区发现了新元古代花岗质片麻岩。应用锆石 U-Pb 测龄方法对花岗质片麻岩进行了年代学研究,23个点的206 Pb/238 U表面谐和年龄均在850 Ma 左右,加权平均为850.2±2.1 Ma。该年龄代表花岗质片麻岩体的侵位时间为新元古代;而较新的499 Ma 年龄可能是后期构造事件改造的新生锆石,反映后期构造热事件的年龄;1518 Ma 的年龄应是本次岩浆作用过程中捕获的早期锆石的年龄,该锆石年龄可能代表本区花岗岩的继承性锆石年龄。伊春花岗质片麻岩所在的地区存在前寒武纪的古老微陆块。  相似文献   

18.
Geological records of Neoproterozoic magmaticevents have recently been identified in the central Phanerozoic orogenic belts of China[1]. In regions of east Qinling orogen[2], Dabie-Sulu orogen[3], north Qaidam Basin orogen[4―6], and southwest Tarim Basin…  相似文献   

19.
SHRIMP U-Pb zircon analyses for a gabbro sample from the Garzê ophiolite block yielded a mean206Pb/238U age of 292 ±4 Ma, which indicated that the spreading time of the Garzê-Litang Tethys was most likely at the earliest Permian. Combined with previous studies, we suggest that the opening of the Tethys in southwest China was derived from breakup of the East Gondwanaland in the late Paleozoic.  相似文献   

20.
西藏洞中拉铅锌矿床石英斑岩锆石U-Pb年代学研究   总被引:2,自引:0,他引:2  
探讨西藏洞中拉铅锌矿区的石英斑岩岩体归属.通过详细的地质填图,并采用LAICPMS锆石U-Pb法年龄测定技术,对石英斑岩进行年代学研究.通过石英斑岩样品中单颗粒锆石22个样品点的分析,得到其206 Pb/238U的加权平均年龄为126.9±1.1 Ma,MSWD=0.96.这一结果否认了这套岩石单元属于始新世林子宗群帕...  相似文献   

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