海水中硼的测定方法   总被引：1，自引：0，他引：1  

王渊  陈国华 《中国海洋大学学报(自然科学版)》1999,(Z1)

介绍了海水中硼的测定主要方法,包括容量法,分光光度法、极谱法、光谱法、离子选择电极法等及其研究进展。  相似文献   

浙江秀山海泥营养物质对环境生物抗氧化性能的影响   总被引：1，自引：0，他引：1  

罗红宇  吴辉辉  解延海  桑卫国  张骏 《海洋与湖沼》2008,39(1):8-13

将浙江秀山海泥样品通过水浸提、离心沉降处理得到水溶相体系海泥提取液,按照20%(体积分数)加入到抗氧化性能评价体系中,采用BCS-Trolox法测定体系的总抗氧化性能,研究了温度、pH和时间对水溶相体系抗氧化性能的影响;分析了含水量为50%的浙江秀山海泥的营养成分,测定了生长于秀山滩涂海泥的菲律宾蛤仔和泥螺肌肉的SOD和GSH-Px的活力。结果表明,与已经开发成保健或泥疗产品的对照泥样相比,秀山海泥富含抗氧化活性营养成分V_A、V_E、V_C、Ge、Fe、Mg、Zn、Sr、Ca,总蛋白酶活性较强;该水溶相体系的抗氧化性能显著,20%的海泥提取液的抗氧化性能与(3.68±0.25)μmol/L的Trolox相当;温度对水溶相体系的抗氧化性能影响显著,pH、时间没有显著影响,因此确定最佳的水溶相体系制备条件为温度60℃、pH 5.6、时间10min;与对照组相比,秀山滩涂海泥能够激活菲律宾蛤仔和泥螺肌肉的SOD、GSH-Px的活性,提高机体的抗氧化性能。  相似文献   

曾昭璇先生的学术思想及其贡献     

吴正  王为 《地理研究》2007,26(6):1069-1076

本文为缅怀我国著名地理学家、地貌学家和教育家曾昭璇先生的纪念论文,阐述了他的学术思想及其贡献。曾昭璇教授学识渊博,在自然地理、地貌、历史地理、人类地理、方志学以及民族学和民俗学等诸多学科领域,都卓有建树。他先后开创"岩石地貌学"、"历史地貌学","人类地理学"三个新领域,填补了学科的空白。曾昭璇先生始终坚持"实践第一"的思想,提倡"地理科学乃经世致用之学",主张科研与生产相结合,科研为国家经济建设服务。曾昭璇先生除科研外,一生以教书为业,致力于地理人材的培养。他非常重视教材的建设,认为教材决定着学生的知识水平和科学素质。提出高等师范的地貌学教材要在"浅、广、新"三方面下功夫。这不仅是编写地貌学教材的要求,更是一种独特的高校地貌教学理念。  相似文献   

湛江硇洲岛文昌鱼(Branchiostoma belcheri)的食性研究     

颜云榕  卢伙胜  白秀娟  赵浩波  廖传翼 《海洋科学》2010,34(8):17-22

于2006年4~7月在湛江硇洲岛海域采集文昌鱼,进行春夏季节不同性别、不同体长组等的胃含物观察分析。结果表明,湛江硇洲岛文昌鱼消化道残留食物成分以泥沙碎屑为主,可辨生物成分有34种,大部分为底栖硅藻,占58.8%,也有少量甲藻、瓣鳃类幼虫、底栖桡足类幼虫和原生动物等。春夏季节的文昌鱼的摄食喜好不尽相同,饵料生物的出现率随着季节的变化有所变化。不同性别文昌鱼的摄食喜好比较相近。文昌鱼到了性腺成熟后才开始进食动物性食物。研究结果表明,文昌鱼摄食藻类、微生物等而自身转化为其他动物的较高营养层次食物,在海洋食物网中具有一定的重要作用。  相似文献   

湖泊表层沉积物可溶性有机氮含量及分布特性   总被引：8，自引：1，他引：7  

林素梅  王圣瑞  金相灿  何星存 《湖泊科学》2009,21(5):623-630

选择鄱阳湖、洞庭湖等6个湖泊的15个表层沉积物样品,用1mol/L KCl溶液提取沉积物中的可溶性有机氮(SON),并研究了SON的含量、分布状况及特性.结果表明,所研究的沉积物SON含量变异较大,在17.18-292.31mg/kg之间波动,平均为134.45 mg/kg,占可溶性总氮(TSN)的51.86%,沉积物总氮的7.14%.污染程度重的沉积物中SON含量均较污染程度轻的高,且SON含量与TN、TSN含量呈正相关,即与沉积物氮污染程度呈正相关,分布状况则与湖泊污染程度、人类活动干扰强度等紧密相关,所研究表层湖泊沉积物巾游离氨基酸(FAA)含量处于4.69-42.04mg/kg间,平均为23.27mg/kg,占SON的18.80%,TN的1.24%,FAA与SON含量呈显著正相关,在沉积物中的平均含骨及在SON中的比例均较土壤中高,说明湖泊沉积物SON有较大的易分解组分,SON与沉积物可溶忭无机氮、有机质、CEC等显著相关,因此,SON是湖泊沉积物氮的重要组成部分,对湖泊富营养化具有重要的影响,特别是对污染严重的沉积物而言,更应重视其SON在湖泊氮循环及富营养化中的作用.  相似文献   

中国煤中铬的分布、赋存状态及富集因素研究进展   总被引：2，自引：0，他引：2  

吴江平  闫峻  刘桂建  郑刘根 《矿物岩石地球化学通报》2005,24(3):239-244

铬是煤中的潜在毒害微量元素,在煤利用过程中铬会发生迁移与转化,并可能释放出造成环境和人体健康的危害。本文分析了中国煤中铬的含量、分布规律、赋存状态及其富集因素等地球化学特征,指出中国煤中铬的含量为0．02～971μg／g,平均为17．18μg／g;煤中铬的赋存状态多样,主要以无机态存在;煤中铬的含量和赋存状态受成煤环境、成煤植物和后生地质作用等因素的影响。  相似文献   

武汉月湖沉积物不同形态氮含量与转换途径的垂直变化   总被引：10，自引：0，他引：10  

陈国元  李建秋  李清曼  周易勇 《湖泊科学》2008,20(4):463-469

描述了2005年6月月湖4个采样点沉积物不同形态氮含量、净硝化速率、净氮矿化速率与硝酸还原酶活性的垂直分布．亚表层（5—10cm）交换态NO3＋-N含量最高,而有效态氮与交换态NH4＋-N含量最低,故具临界意义．有效态氮多以交换态NH4＋-N的形式贮存于表层（0—5cm）与底层（〉10cm）,且底层含量较高,这种分布与缺氧状态有关．表层沉积物总氮和有机态氮含量、净硝化速率、净氮矿化速率与硝酸还原酶活性均高,间隙水中NH4＋-N浓度亦取峰值,而溶解态N03--N浓度最低,据此提出氮循环的基本过程：有机态氮经矿化与硝化产生NH4＋-N与NO3-N,同时导致有利于NH4＋-N生成的缺氧状态,并促使部分NO3-N异化还原为NH4＋-N,二者共同构成表层间隙水中丰富的NH4＋-N源,总之,富营养化湖泊表层沉积物富含有机态氮,故为氮生物地球化学循环的最为活跃的层面,而NH4＋-N则为最具有效性且含量最高的形态．  相似文献   

Water contents of clinopyroxenes from sub‐arc mantle peridotites          下载免费PDF全文

Michael Turner  Simon Turner  Dawnika Blatter  Rene Maury  Michael Perfit  Gene Yogodzinski 《Island Arc》2017,26(5)

One poorly constrained reservoir of the Earth's water budget is that of clinopyroxene in metasomatised, mantle peridotites. This study presents reconnaissance Sensitive High‐Resolution, Ion Microprobe–Stable Isotope (SHRIMP–SI) determinations of the H₂O contents of (dominantly) clinopyroxenes in rare mantle xenoliths from four different subduction zones, i.e. Mexico, Kamchatka, Philippines, and New Britain (Tabar‐Feni island chain) as well as one intra‐plate setting (western Victoria). All of the sub‐arc xenoliths have been metasomatised and carry strong arc trace element signatures. Average measured H₂O contents of the pyroxenes range from 70 ppm to 510 ppm whereas calculated bulk H₂O contents range from 88 ppm to 3 737 ppm if the variable presence of amphibole is taken into account. In contrast, the intra‐plate, continental mantle xenolith from western Victoria has higher water contents (3 447 ppm) but was metasomatised by alkali and/or carbonatitic melts and does not carry a subduction‐related signature. Material similar to the sub‐arc peridotites can either be accreted to the base of the lithosphere or potentially be transported by convection deeper into the mantle where it will lose water due to amphibole breakdown.  相似文献   

Experimental assessment of the seismic performance of hospital cabinets using shake table testing     

Luigi Di Sarno  Gennaro Magliulo  Danilo D'Angela  Edoardo Cosenza 《地震工程与结构动力学》2019,48(1):103-123

An experimental investigation of hospital building equipment is presented. Dynamic properties and seismic performance of typical ambulatory freestanding cabinets are assessed by unidirectional and bidirectional shake table tests, also considering the presence of internal partitions and cabinet contents. Vulnerability analysis is performed according to the most recent and reliable assessment methods, evaluating the influence of different parameters of the sample cabinets. The performance criteria referred within this research are the limit states reached by the specimens (ie, rocking and overturning) and by their contents (ie, overturning and breaking). Fragility curves are evaluated for the components and the contents, considering both acceleration and velocity intensity measures, and also using dimensionless intensity measures developed in recent studies. The outcomes of the present study confirm the findings of previous laboratory tests and numerical simulations carried out by the same authors and provide a further insight for the reliable seismic performance assessment of hospital cabinets and their contents.  相似文献   

Modal-based ground motion selection procedure for nonlinear response time history analysis of high-rise buildings     

Yang Liu  J.S. Kuang  Terry Y.P. Yuen 《地震工程与结构动力学》2020,49(1):95-110

The selection of representative input ground motions (IGMs) is important for a proper nonlinear response time history analysis (NLRHA) of modern structures. The prevailing IGM selection procedure requires that the response spectra of selected ground motions are matched with the code-specified design spectra, while the effect of the frequency contents combination in the time domain on the multimode interactions is not considered. Ignoring the effect of the frequency contents combination in the time domain of IGMs may cause significant variations in the analysis results for selected IGMs, although they are matched to the same design spectrum. In this paper, a modal-based ground motion selection (MGMS) procedure is proposed as a supplement to spectrum matching-based IGM selection procedures for selecting proper IGMs that can sufficiently induce the multimode interactions. In the proposed procedure, three equivalent single-degree-of-freedom (ESDOF) systems are developed by pushover analysis. NLRHA is then conducted for these ESDOF systems with a set of 20 seed IGMs chosen by the spectrum-matching–based selection procedure. Finally, seven IGMs are selected from the seed IGMs for NLRHA in the full structural model. To verify MGMS, seismic demands of high-rise buildings were computed by NLRHA with seven MGMS-selected IGMs, seven IGMs with closest spectrum matching, and groups of seven randomly selected IGMs derived from three different sets of 20 seed IGMs. The computed seismic demands with MGMS-IGMs show very good agreement with the mean demands determined using the whole set of seed IGMs, while the deviation is much lesser compared with those groups of randomly selected IGMs.  相似文献