Different physical, chemical and biological processes may lead to distinctive nitrogen and oxygen isotope fractionations.

引起地下水中NO3含量顯著減少的不同物理欧美AV在线免费不卡、化學(xué)和生物過(guò)程，所產(chǎn)生的氮人人玩人人看人人靠,人人想人人操人人、氧同位素分餾效應(yīng)有明顯差別。

It is the first time to use isotope gauge to continuous examination of the level of coke in the thermal cracking tower in China.

于二疊紀(jì)—古近紀(jì)地層中發(fā)現(xiàn)動(dòng)物化石国产欧美黄色、植物化石和孢粉多屬多種AAAAAA片毛片。7九九r视频。中國(guó)雙節(jié)行軍蟻屬一新種膜翅目，蟻科

Such features are typical of ancient lower continental crust, e.g., Archean granulite terranes that experienced extensive U-Th loss and developed time-integrated low radiogenic Pb compositions. The occurrence of the west Ujimqin andesites indicates the existence of ancient continental lower crust beneath the NE China fold belt.4 The Mesozoic granitoids in the Zhangguangcai Range and Jiamusi block have lower Nd ε_(tái)(Nd =-3.5～+ 2.1, T_ = 1.0～1.27Ga and highly radiogenic Pb and Sr isotopic composition ~(206Pb/~(204)Pb = 18.4～18.9,~(87)Sr/~(86)Sr = 0.705～0.711, suggesting that the pelagic sediments of the Paleo-Asian Ocean or their metamorphosed derivates were an important component in the region.5 The Pb isotope mapping results show that the mafic rocks in the northern Hinggan Mountains have higher and weakly variable ~(206)Pb/~(204)Pb ratios than those from the southern Hinggan Mountains and the Liaoyuan-Yanji area.

該套巖石的出現(xiàn)為證明東北地區(qū)存在古老大陸下地殼提供了重要證據(jù)操一操在线。4張廣才嶺-佳木斯地區(qū)中生代花崗巖表現(xiàn)出低ε_(tái)(-3.5～+2.1)、高T_(1.0～1.27Ga)和高放射成因Sr~(87Sr/~(86)Sr=0.705～0.711和Pb同位素組成~(206Pb/~(204)Pb=18.4～18.9免费AV黄片，反映了古亞洲洋遠(yuǎn)洋沉積物或變沉積巖為區(qū)域地殼的重要組分之一强奸a片久久a。5同位素填圖結(jié)果表明，大興安嶺北區(qū)基性火山巖表現(xiàn)出較高且變化小的~(206)Pb/~(204)Pb比值一区无码在线；而南興安嶺-遼源-延吉地區(qū)中生代基性火山巖整體上表現(xiàn)出相對(duì)北區(qū)低~(206)Pb/~(204)Pb同位素比值特征未满十八18禁止观看网站。

There are a number of amphiboles developed in metamorphic rocks in sands, and the oxygen isotope compositions of quartz in dune sands and similar to that of metamorphic quartz.

沙物質(zhì)和巖漿巖在所含角閃石種類以及普通角閃石化學(xué)成分上的差異性明顯大于相似性，說(shuō)明后者為前者提供的角閃石有限影音先锋操逼网。

In chapter 2,the bi-electrophilicity ofα-CAPAs(Gly-CAPA,Ala-CAPA) was identified by the isotope analysis ~(18O,~(15)N and furtherproved by trappingα-CAPA with nucleophiles such as water,amino acids,phosphateand methanol in alkaline media which yielded phosphorylated products,namely,theNPAAs and N-(mono-substituted)phosphoryl amino acids.

自CAPA的結(jié)構(gòu)被提出以來(lái)，CAPAs的化學(xué)反應(yīng)幾乎沒(méi)有得到進(jìn)一步的研究99se在线播放，所以本論文的第二章研究了以甘氨酸-CAPA和丙氨酸-CAPA為代表α-CAPAs分子，通過(guò)同位素標(biāo)記實(shí)驗(yàn)~(18O黄色网站在线播放，~(15)N證明了CAPA分子具有兩個(gè)親電中心。

In chapter 2,the bi-electrophilicity ofα-CAPAs(Gly-CAPA,Ala-CAPA) was identified by the isotope analysis ~(18O,~(15)N and furtherproved by trappingα-CAPA with nucleophiles such as water,amino acids,phosphateand methanol in alkaline media which yielded phosphorylated products,namely,theNPAAs and N-(mono-substituted)phosphoryl amino acids.

同時(shí)欧美一级婬片日本高清视，CAPA和親核試劑如水，氨基酸国产精品毛片无码,啦啦啦，磷酸和甲醇分子反應(yīng)可以生成各種磷酰化產(chǎn)物，如NPAAs和N-磷上單取代的磷醺咔逦蘼胄园化氨基酸。

Short-lived radionuclides and long-lived isotope systems are normally used to date chondrites; the former systems can provide only relative ages while the later can provide absolute formation ages of chondrules, in contrast.

隕石年代學(xué)研究中常用定年工具包括短半衰期和長(zhǎng)半衰期放射性同位素體系www.jizz.com中国破处，其中前者可以給出隕石形成的相對(duì)年齡，而后者則可以給出絕對(duì)形成年齡日韩精品娱乐在线观看网站免费。

A team led by Stanford University scientists reconstructed dietary sources of recent and ancient condors by measuring carbon and nitrogen isotope concentrations in feather and bone remains.

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Today, most cyclotrons are used either for instructional purpose or for isotope production

今天大多數(shù)回旋加速器是用在教學(xué)上，或者用于同位素生產(chǎn)国产激情视频久久久。

The desorbed methane carbon isotope of coal core samples collected from Jincheng area, South Qinshui basin was measured.

對(duì)取自沁水盆地南部晉城地區(qū)的煤芯樣中的解吸氣進(jìn)行了甲烷碳同位素測(cè)定国产爆乳日韩精品视频迅雷下载。