莼菜( Brasenia schreberi )冬芽对 Cr6+污染的抗性反应   总被引：3，自引：0，他引：3  

杨顶田  施国新  宋东杰  陈伟民 《湖泊科学》2001,13(2)

研究了Cr6 +污染对莼菜冬芽外部形态及过氧化物酶、硝酸还原酶活性、叶绿素、O-·2 、MDA的含量等生理指标的影响 .结果显示 :Cr6 +对莼菜毒害机制在于抑制酶活性和损害细胞膜系统 .在培养第三天时叶绿素的含量随着Cr6 +浓度的增加而降低 ;过氧化物酶的活性在 10mg/L中最高 ;硝酸还原酶活性除在 5mg/L中的略微升高外 ,在 10 - 4 0mg/L之间随着Cr6 +培养浓度的升高而降低 ;O-·2 的含量在 5mg/L中的最高 ,在 10mg/L中略高于对照 ,在随后培养中随浓度的升高而降低 ,MDA的含量变化趋势和O-·2 相似  相似文献   

Controls on englacial sediment deposition during the November 1996 jökulhlaup,Skeiđarárjökull,Iceland     

Matthew J. Roberts  Andrew J. Russell  Fiona S. Tweed   skar Knudsen 《地球表面变化过程与地形》2001,26(9):935-952

This paper presents sedimentary evidence for rapid englacial debris entrainment during jökulhlaups. Previous studies of jökulhlaup sedimentology have focused predominantly on proglacial impact, rather than depositional processes within glaciers. However, observations of supraglacial floodwater outbursts suggest that englacial sediment emplacement is possible during jökulhlaups. The November 1996 jökulhlaup from Skei?arárjökull, Iceland presented one of the first opportunities to examine englacial flood deposits in relation to former supraglacial outlets. Using observations from Skei?arárjökull, this paper identifies and explains controls on the deposition of englacial flood sediments and presents a qualitative model for englacial jökulhlaup deposition. Englacial jökulhlaup deposits were contained within complex networks of upglacier‐dipping fractures. Simultaneous englacial deposition of fines and boulder‐sized sediment demonstrates that englacial fracture discharge had a high transport capacity. Fracture geometry was an important control on the architecture of englacial jökulhlaup deposits. The occurrence of pervasively frozen flood deposits within Skei?arárjökull is attributed to freeze‐on by glaciohydraulic supercooling. Floodwater, flowing subglacially or through upglacier‐dipping fractures, would have supercooled as it was raised to the surface faster than its pressure‐melting point could increase as glaciostatic pressure decreased. Evidence for floodwater contact with the glacier bed is supported by the ubiquitous occurrence of sheared diamict rip‐ups and intra‐clasts of basal ice within jökulhlaup fractures, deposited englacially some 200–350 m above the bed of Skei?arárjökull. Evidence for fluidal supercooled sediment accretion is apparent within stratified sands, deposited englacially at exceptionally high angles of rest in the absence of post‐depositional disturbance. Such primary sediment structures cannot be explained unless sediment is progressively accreted to opposing fracture walls. Ice retreat from areas of former supraglacial outbursts revealed distinct ridges characterized by localized upwellings of sediment‐rich floodwater. These deposits are an important addition to current models of englacial sedimentation and demonstrate the potential for post‐jökulhlaup landform development. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

靖安油田延长组长6段低孔低渗透储层特征及评价   总被引：4，自引：8，他引：4  

文玲  胡书毅  田海芹 《西北地质》2001,34(4):53-60

靖安油田延长组长6段储层为湖相三角洲前缘砂体，长6期是三角洲建设的高峰期，发育三角洲水下分流河道与河口砂坝砂体及远坝微相。孔隙空间主要是原生孔隙及由次生原因形成的孔隙和裂缝。研究表明：孔隙的形成和演化受成岩作用的控制。主要成岩作用有机械压实作用，胶结作用和溶蚀作用。压实作用，胶结作用不利于孔隙的演化，而溶蚀作用有利于次生孔隙的形成。从而使某些砂岩段在低孔低渗储层中形成较发育的次生溶蚀孔隙的成岩微裂缝，并成为有效孔隙，通过综合评价认为，水下分流河道和河口砂坝微相为本区最好的储集层。  相似文献   

悬浮液原子荧光光谱法测定化探样品中的痕量汞   总被引：3，自引：0，他引：3  

王桂清  刘汉东 《岩矿测试》1996,15(4):293-295

拟定了将悬浮液技术与汞蒸气原子荧光光谱法相结合测定化探样品中痕量Ｈｇ的分析方法。控制悬浮液中试样粒度在２００目，试样质量浓度１５ｇ／Ｌ，用电磁搅拌和载气搅拌保证悬浮液分散稳定，水溶液标准作校正曲线，方法的检出限为６ｎｇ／ｇＨｇ。对水系沉积物国家标准物质中痕量Ｈｇ进行测定，结果与标准值相符，对含Ｈｇ０１０μｇ／ｇ的ＧＢＷ０７３０５（ＧＳＤ５）测定１１次，ｘ为０１０５μｇ／ｇ，ＲＳＤ为５４％。  相似文献   

3≈6 Months Variation of Sea Surface Height in the South China Sea and Its Adjacent Ocean     

Jianyu Hu  Hiroshi Kawamura  Huasheng Hong  Fumiaki Kobashi  Dongxiao Wang 《Journal of Oceanography》2001,57(1):69-78

Sea surface height (SSH) variations with a period of 36 months (SSH36 variations) in the South China Sea (SCS) and its adjacent ocean are intensively investigated using six years of TOPEX/POSEIDON-derived SSH data. The results show that there appears higher energy of SSH36 variations in the east of the Luzon Strait and in some areas of the SCS, both of which are correlated with each other. The SSH36 variations usually propagate westward in the subtropical region of the northern Pacific Ocean and turn northward in the east of the Luzon Strait while they sometimes propagate into the SCS through the Luzon Strait with the phase speed of about 11–12 cm/s, which may be considered as Rossby waves. It can be inferred that the SSH36 variations are strongly associated with current structures and eddies in the SCS because of their significant intensiveness. The SSH variations with the period of 6 months are more dominant than those with the other periods in the SCS.  相似文献   

用6－甲氨基嘌呤诱导贻贝四倍体胚胎     

蔡国雄 《热带海洋学报》1996,(4)

在滤过海水中以４×１０（－４）ｍｏｌ·Ｌ（－１）６－甲氨基Ｃ嘌呤（６－ＤＭＡＰ）处理贻贝Ｍｙｔｉｌｕｓｅｄｕｌｉｓ受精卵或胚胎，受精激活后５０或１２０ｍｉｎ处理２０—３０ｍｉｎ，分别抑制第一或第二次有丝分裂，以诱导四倍体胚胎。顶荧光显微观察表明，６－ＤＭＡＰ有效地抑制了第一和第二次卵裂。它使细胞核染色质分散，抑制了原核的移动和染色体的分离，并防碍卵裂沟和极叶的形成，从而诱导出四倍体胚胎。对第一次卵裂的抑制产生８２．８％的四倍体胚胎；第二次卵裂抑制产生５８．６％的四倍体胚胎。由于６－ＤＭＡＰ如此有效，而且价格便宜以及对人体无害，与沿用的化学诱导剂细胞松弛素Ｃ．Ｂ．相比，它应该可以成为双壳类软体动物染色体操作研究的理想化学诱导剂之一。  相似文献   

AccQ-Tag法测定毛蚶抗贫血口服液中的氨基酸含量     

徐赤  顾谦群  付余强 《中国海洋大学学报(自然科学版)》2002,32(3):380-384

以 6 -氨基喹啉 - N-羟基琥珀酰亚胺基氨基甲酸酯 (AQC)为衍生剂 ,与毛蚶抗贫血口服液中的氨基酸柱前定量衍生 ,用 Waters HPL C仪 ,Acc Q- Tag TM专用 C18柱 (3.9mm× 15 cm) ,以140 mmol· L-1的醋酸钠溶液 (p H5 .0 2 )为溶剂 A,乙腈为溶剂 B,超纯水 (Milli- Q水 )为溶剂 C,进行梯度洗脱 ,检测波长为 2 4 8nm,35 min测试完毕。各种氨基酸测定的重现性 RSD%均 <3.0 %(n=5 )。该方法简便快速 ,结果准确可信。  相似文献   

中国对虾及中华绒螯蟹多倍体诱导中6-DMAP在卵子中残留量的检测     

吴长功  张晓军  崔朝霞  周令华  相建海 《海洋科学集刊》2002,(44):106-110

海洋动物多倍体的诱导目前已成为海水养殖中品种改良的重要手段(楼允东，1984)。在美国，太平洋牡蛎和虹鳟的多倍体诱导已大规模应用于生产，并获得良好的经济和社会效益。我国也先后开展了鱼类(桂建芳等，1991；尤锋，1993)、中国对虾(戴继勋等，1993；相建海等，1992)、贝类(喻子牛等，1995)及中华绒螯蟹(陈立侨等，1997)等多种海洋动物多倍体诱导的研究，并取得了一些进展。6-二甲基氨基嘌呤(6-DMAP)由于其低毒、经济和高效，目前已成为海洋动物多倍体诱导中经常使用的诱导剂，但至今，国内外尚无关于6-DMAP在卵子内的残留的报道。在环境保护和生物安全倍受关注的今天，人们非常关心多倍体诱导食物的安全性问题，本文首次利用高压液相色谱技术检测了在中国对虾和中华绒螯蟹多倍体诱导处理后，卵子和幼体内6-DMAP的残留量，并对检测结果进行了分析讨论。  相似文献   

Period analysis of theδ Scuti star HD93044     

Zong-Li Liu 《Astrophysics and Space Science》1993,210(1-2):197-200

HD93044 was observed electrophotometricaly on April 21, May 1, 2 and 4, 1991 at Xinglong Station of Beijing Astronomical Observatory. Combining the data with Li Zhiping's data together and a period analysis was completed using a program which consists of a combination of Fourier transforms of prewhitened data and the multifrequency least squares of brightness residuals (LSR). Three pulsation frequencies (11.90809, 16.79553, 22.44827 cycles per day) with visual amplitudes between 0.0056 and 0.0203 mag were found. The solution fits the observations to +0.0071 mag which is equal to the mean square deviation of observations. The first frequency (11.90809 cycles per day) must be the right value of the fundamental frequency of HD93044.  相似文献   

WRF2.2在FC6系统上的安装运行     

娄波  徐斌  侯志明 《内蒙古气象》2007,(6):44-45

简要介绍了WRF模式的概况,并着重介绍了如何在Fedora Core6上安装运行WRF模式的最新版本WRF2.2。它主要包括两个部分,WPS前处理模块及WRF主模块。在介绍WPS前处理模块时,还对WPS的图形界面程序DomainWizard进行了简介。  相似文献