一株产海藻糖合成酶南极海洋低温细菌的鉴定   总被引：2，自引：0，他引：2       下载免费PDF全文

俞勇  李会荣  陈波  曾胤新 《极地研究》2005,17(2):127-133

从南极普里兹湾海域海水中分离到一株产海藻糖合成酶的海洋低温细菌BSw10041,革兰氏阴性,杆状,有极生鞭毛,能运动,菌落半透明。进行了常规生理生化和BIOLOG GN2细菌鉴定系统测试,结果表明菌株BSw10041与恶臭假单胞菌(Pseudomonas putida)的表型特征非常相似。为了进一步确定菌株BSw10041的分类学地位,测定了其16S rDNA序列,分析了相关细菌相应序列的同源性,构建了系统发育树,结果表明BSw10041与P．putida的亲缘关系最近。综合上述结果,菌株BSw10041可鉴定为Pseudomonas putida,定名为Pseudomonas putida BSw10041。  相似文献   

Influence of river channel geometry in stream flow modelling and guidelines for field investigation          下载免费PDF全文

Hongbo Zhang  Fan Zhang  Xiaonan Shi  Chen Zeng  Dong‐Sin Shih  Gour‐Tsyh Yeh  Daniel R. Joswiak 《水文研究》2014,28(4):2630-2638

Fully physics‐based, process‐level, distributed fluid flow and reactive transport hydrological models are rarely used in practice until recent years. These models are useful tools to help understand the fundamental physical, chemical, and biological processes that take place in nature. In this study, sensitivity analyses based on a mountain area river basin modelling study are performed to investigate the effect of river channel geometric characteristics on downstream water flow. Numerical experiments show that reduction in the river channel geometric measurement interval may not significantly affect the downstream water stage simulation as long as measurement accuracy at special nodes is guaranteed. The special upstream nodes include but are not limited to 1) nodes located close to the observation station, 2) nodes near the borders of different land covers with considerable riverbed roughness changes, 3) nodes at entering points of tributaries causing discharge jump and 4) nodes with a narrow cross‐section width that may control the flow conditions. This information provides guidelines for field investigation to efficiently obtain necessary geometric data for physics‐based hydrological modelling. It is especially useful in alpine areas such as the Tibetan Plateau where field investigation capability is limited under severe topography and climate condition. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

The establishment of gas accident risk tolerability criteria based on F–N curve in China     

Ying Zhang  Yun Luo  Jingjing Pei  Yu Hao  Zhu Zeng  Yanpeng Yang 《Natural Hazards》2015,79(1):263-276

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A detailed post‐IR IRSL dating study of the Niuyangzigou loess site in northeastern China          下载免费PDF全文

Shuangwen Yi  Jan‐Pieter Buylaert  Andrew S. Murray  Huayu Lu  Christine Thiel  Lin Zeng 《Boreas: An International Journal of Quaternary Research》2016,45(4):644-657

In this study, we report standard quartz SAR OSL and post‐IR infrared (IR) stimulated luminescence (post‐IR IRSL; pIRIR₂₉₀) measurements made on sand‐sized quartz and K‐feldspar extracts from the loess‐palaeosol sequence at Niuyangzigou in northeastern China. The quartz OSL characteristics are satisfactory. Extensive pIRIR_50,290 dose recovery tests were performed by adding doses on top of the natural dose. We found that dose recovery ratios improve significantly when the test dose ranges between ~15 and ~80% of the total dose, and good dose recovery (within ±5% of unity) can be obtained up to ～800 Gy. Otherwise, the dose recovery ratio deviates from unity. The D_e values also depend on the test dose size and so we conclude that the effect of test dose size should be routinely considered in pIRIR dating. First IR stimulation plateau pIRIR₂₉₀ results are compared with multiple elevated temperature ‐pIRIR (MET‐pIRIR) data. It appears that the low temperature MET‐pIRIR data are strongly affected by poor dose recovery, but this is not the case for the pIRIR₂₉₀ results. Natural signal measurements at the highest (first IR) stimulation temperature on a sample expected to be in field saturation suggest that ~10% signal loss occurs in pIRIR signals. Long‐term laboratory bleaching experiments (>80 days) show that a constant (or very difficult to bleach) residual pIRIR₂₉₀ signal is reached after ~300 h, corresponding to a dose of 6.2±0.7 Gy. Quartz OSL and feldspar pIRIR_50,290 ages are in good agreement at least back to c. 70 ka. Beyond this the quartz ages begin to underestimate but the feldspar ages are in agreement with the expected Last Interglacial age palaeosol.  相似文献   

A seasonal changes-based equilibrium strategy for coal–water conflict: a case study at the Yanzhou coal field     

Jiuping Xu  Chengwei Lv  Jinzhong Zuo  Mengxiang Zhang  Ziqiang Zeng 《Environmental Earth Sciences》2016,75(8):637

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赣东北朱溪矿床云英脉型钨矿体及矽卡岩型钨铜矿体成因关系 ——来自石榴子石、白钨矿原位U-Pb年代学及微量元素特征的证据     

彭勃  王先广  胡正华  代晶晶  万新  章培春  顾枫华  陈红瑾  傅明海 《地质学报》2023,97(5):1508-1525

朱溪矿床是江南钨矿带中产于燕山期中酸性侵入岩与晚古生代碳酸盐岩接触带附近以矽卡岩矿体为主的钨铜矿床,发育“上铜下钨”的空间分带。浅部发育矽卡岩型和脉型铜矿体,深部发育矽卡岩型钨铜矿体、云英细脉-网脉型钨矿体及蚀变花岗岩型钨矿体。浅部矽卡岩型铜矿体中石榴子石U-Pb年龄为152.6±2.6 Ma、深部云英脉型钨矿体中白钨矿U-Pb年龄为153.4±2.2 Ma、深部矽卡岩型钨铜矿体中白钨矿U-Pb年龄为153.9±2.7 Ma,三者时代在误差范围内一致,表明钨、铜矿化均形成于同一热液体系,结合云英脉型钨矿体和矽卡岩型钨铜矿体中两类白钨矿的微量元素特征分析,流体起源于富WO₄^2-、低Sr的高分异岩浆热液,白钨矿是以Ca²⁺空位的方式置换REE³⁺,稀土元素的分配行为记录了不同类型矿化流体性质。云英脉型钨矿化形成于还原环境,且氧逸度的显著降低以及围岩提供大量Ca²⁺促进了白钨矿的沉淀,而矽卡岩型钨铜矿化为相对开放的热液体系,后期经历了氧逸度升高,增强了流体富集金属Cu的能力,从而萃取...  相似文献   

鄂尔多斯盆地长7段页岩生烃活化能分布及其对页岩原位转化的启发     

郑瑞辉  李志鹏  曾文人  余麒麟  满凯旋  肖伟  张枝焕 《地质学报》2023,97(1):197-209

鄂尔多斯盆地三叠系延长组7段(长7段)中—低熟(R_o<1.0%)页岩面积占该段页岩总面积的90%左右,中—低熟页岩油/油页岩资源丰富,原位转化作为实现其工业开采的有效途径日益受到各方的关注。生烃转化率和活化能是影响页岩原位转化和开采潜力的关键因素,前人研究表明研究区长7段页岩生烃活化能分布特征存在较大的差别,但其分布规律及其控制因素尚不清楚,尤其是有机质丰度、成熟度等对页岩生烃特征和动力学过程的控制作用及其成因机制尚不明确,这必将制约研究区页岩原位转化条件和资源潜力的评价。本次研究选取了长7段成熟度相近、不同有机质丰度的5块页岩样品以及有机质丰度相近、不同成熟度的5块页岩样品,通过开放热模拟实验确定了样品的生烃动力学参数,讨论了有机质丰度和成熟度对长7段页岩动力学特征的影响。根据烃源岩生烃过程的时间-温度补偿原理,将实验室条件下获得的动力学参数外推至页岩原位转化条件下,分析了有机质丰度和成熟度对长7段页岩原位转化温度区间的影响。结果表明,在成熟度相近的情况下,受有机质中藻类体等腐泥组的富集程度影响,烃源岩的生烃活化能随有机质丰度的增大而增大;在有机质丰度相近...  相似文献   

塔河油田奥陶系走滑断裂体系特征及成因机制     

马庆佑  曾联波  徐旭辉  耿锋  童亨茂  蒋华山  肖坤泽 《地质学报》2023,97(2):496-506

塔河油田奥陶系“断溶体”油藏是塔里木盆地油气勘探开发的重要对象。本文对塔河油田10区西、于奇西、于奇8井三块三维地震资料开展了精细的走滑断裂构造解析,并在此基础上对塔河油田走滑断裂体系的形成演化过程与成因机制有新认识。研究结果表明：(1)除了在塔河油田南部10区西、托普台等区块发育典型的“X”型共轭走滑断裂体系外,首次发现塔河油田北部于奇地区发育非对称式共轭走滑断裂体系,据此划分出塔河油田南、北两大走滑断裂体系,但两者在形成时间、最大主应力方向、动力学来源等方面均存在明显差异;(2)两大走滑断裂体系的形成及演化过程大致分为3个阶段：加里东期中期I幕形成南部NNE、NNW两组走向的“X”型共轭走滑断裂体系,最大主压应力方向为N3°E,主要受到西昆仑洋俯冲消减作用产生的由S向N的挤压应力;加里东期晚期—海西期早期形成北部以近NE走向为主、少量SN走向组成的非对称式共轭走滑断裂体系,最大主压应力方向为N23°E,主要受到南天山洋俯冲消减作用产生的由N向S的挤压应力,海西期晚期继承性活动,主应力方向保持不变;印支期—燕山期两大走滑断裂体系继承性活动,最大主压应力方向为N37°E,主要受到南部古...  相似文献   

贵州铝土矿含矿岩系中锂的分布特征及富集机理     

金中国  郑明泓  刘玲  黄智龙  叶霖  吴莎  曾道国  谷静 《地质学报》2023,97(1):69-81

锂是我国关键矿产和高新产业发展的战略性资源之一。贵州铝土矿资源丰富,含铝岩系分布广,勘查发现铝土矿(岩)中伴生大量的锂资源。研究认为,全省含铝岩系中Li含量高,变化范围大(0.55×10^-6～2725.03×10^-6),平面上Li含量总体呈北东(务正道成矿区)、南西(修文-清镇成矿区)高,中间(播州-瓮安成矿区)低的分布态势;剖面上Li主要富集在矿系上部的致密状铝土岩(矿)中,Li含量一般>500×10^-6,矿系中土状铝土矿(岩)Li含量一般<30×10^-6;气候温湿、风化及淋滤作用强的陆相湖泊沉积环境,有利于高岭石为主的黏土矿物形成及Li⁺与Al³⁺、Mg²⁺、Fe³⁺、Fe²⁺发生类质同象,或被吸附进入黏土矿物层间构造同迁移同富集,Li与Al₂O₃含量呈正相关关系;成岩成矿后的次生改造阶段,古地磁测量及CIA显示为炎热潮湿的氧化环境...  相似文献   

青藏高原第四纪冰川作用及其气候响应的讨论     

欧先交  周尚哲  赖忠平  曾兰华 《第四纪研究》2015,35(1)

关于青藏高原和周边山地第四纪冰川作用及其气候响应存在不同观点.一些学者认为老冰期主要发生在氧同位素奇数阶段;MIS 3和早全新世存在规模较大的冰川前进;南亚季风对青藏高原冰川作用起主导作用(水汽驱动).另一些学者则认为青藏高原冰川作用主要对应于氧同位素偶数阶段;冰川发育是构造隆升-冰期气候耦合的产物(低温驱动).本文基于现有的陆地生成宇宙核素(TCN)和光释光(OSL)等年代结果总结了不同时间尺度和不同类型冰川波动与气候变化历史的对比,并对几个关键的争议问题做了讨论.结果表明,在不同类型冰川区和不同时间尺度下,冰川作用在湿润期和低温期都有可能发生,但总体上主要与低温相对应.青藏高原冰川对气温的响应似乎更为敏感.MIS 3冰进规模较大可能是降水较多结合冷期(或冷事件)降温所致,显示了印度季风降水和气温波动对高原冰川的共同作用.早全新世冰进也与印度季风和北半球冷事件关系密切.目前的测年数据还没有推翻“冰期发生在氧同位素偶数阶段”这种传统认识.当前急需更多精确的数字定年工作,以不断更新对青藏高原冰期时代及其气候响应机制的了解.  相似文献