共查询到20条相似文献，搜索用时 21 毫秒
1.
xiODUonONThemaoreleInent(oxygen)ofldeinthemarineeresySteInisCycledalongapartho-larrouteinWhwhthethetcanbedrawnfromtheexternlenvirDnmentintoorgan-isim,andthenberetumedtotheenvbonmentfromtheorganisrns.TheDocontentinseawatCfisinIlUentalbyorganisms,imtS,temPeratureandoxidation.So,studyonDoisoftoortanceinoasnographyastheDofluxisofgreatsignfonceinmarinebiogeochdricalcydes.'MareRIAnooMEmOorlnthisstudy,datafroml98O~l992multi-disdplinaryinvestigationsinthecenthel,northeastem,andsouthernSrswe… 相似文献
2.
长江下游鳊鱼遗传多样性的RAPD分析 总被引：2，自引：0，他引：2
应用RAPD技术对长江下游鳊鱼群体的遗传多样性进行分析,从40个随机引物中筛选出28个引物对鳊鱼24个个体的基因组DNA进行扩增,共检测到178个位点,分子片段在0.2～2.0kb之间,其中多态位点83个,占46.63%;个体间最大的遗传距离为0.1326,最小的遗传距离为0.0476,平均遗传距离为0.0885;群体的Nei基因多样性指数为0.2593,Shannon多样性指值为0.0986。与其他鱼类的遗传多样性研究结果相比,长江下游鳊鱼群体的遗传多样性处于中等水平。 相似文献
3.
浅析翡翠的岩石类型对其比重、折射率的影响 总被引：1，自引：0，他引：1
翡翠的矿物组成、岩石类型不同，将会对翡翠的比重、折射率产生直接的影响。从翡翠的岩石学、矿物学角度出发，讨论了翡翠的岩石类型，依据组成翡翠的主要矿物的比重和折射率值，建立了翡翠矿物组成成分及含量与其比重、折射率关系图解，确定了各种翡翠的比重、折射率变化范围分别为：2．93～3．60和1．593～1．750；优质翡翠的比重、折射率分别为：3．178-3．240和1．644～1．657．为翡翠的质量评估提供了客观依据。 相似文献
4.
阎怀兰 《广东海洋大学学报》2011,31(5):68-71
近期中国电影艺术娱乐化趋势的原因,可以从电影生产链条中的市场、生产者和消费者三个方面进行探究。一是社会转型期电影的产业化发展、市场的激烈竞争和票房的功利追求的必然结果,二是源于电影生产者对电影市场化的探索和艺术创作意识的模糊,三是大众文化氛围下观众娱乐消遣的需求。正确认识电影娱乐化这一现象,理解电影的娱乐性和商业性、艺术性的关系,有助于电影艺术的发展。 相似文献
5.
内蒙古白音诺尔铅锌矿铅同位素研究 总被引：10，自引：0，他引：10
内蒙古白音诺尔铅锌矿床是大兴安岭地区储量最大的铅锌矿床,矿体主要沿花岗闪长(斑)岩与大理岩接触带产出。为了查明成矿物质来源,对矿石中的硫化物和矿区内及外围主要侵入岩开展了铅同位素示踪分析。测试结果表明:矿石中硫化物的N(206Pb)/N(204Pb)为18.266～18.372,平均值18.296,N(207Pb)/N(204Pb)为15.501～15.579,平均值15.536,N(208Pb)/N(204Pb)为38.016～38.339,平均值38.138。铅同位素年龄校正计算结果表明:矿石中硫化物的Pb同位素比值与大理岩和花岗闪长(斑)岩非常相似,表明矿石中的铅主要来自花岗闪长(斑)岩和大理岩,说明成矿物质也主要来自这两类岩石,进一步证明了白音诺尔铅锌矿床的成矿与花岗闪长(斑)岩和大理岩有关,属于矽卡岩型矿床,与喷流沉积型和火山岩块状硫化物矿床有明显的差别。与区域上其他银多金属矿床对比发现,本区银多金属矿床的Pb同位素组成非常相似,其组成范围多有重叠,暗示这些矿床的矿石铅来源也非常相似,可能表明有一个共同的富银的基底或地层为这些银多金属矿床的形成提供了成矿物质来源。 相似文献
6.
An experiment on the optimum dietary protein content for the black sea bream using semi-purified diets showed the optimum
is 50.19% by weight as inferred from the growth rate and food consumption of the fish.
Another experiment on the proper ratio of animal to plant protein in its diet using sandeel as the animal protein source and
peanut cake meal as plant protein source showed that the ratio had great effect on its growth and should be 1.00: 0.89–0.96
as judged from the growth rate and food consumption of the fish.
Contribution No. 1973 from the Institute of Oceanology, Chinese Academy of Sciences. 相似文献
7.
王锐 《广东海洋大学学报》2009,29(2)
农村税费改革,在调整国家与农民经济关系的同时,也为乡村关系的发展注入了新的变量:乡镇政府职能由"管治"转向"服务";乡村财政收入减少,基层政府运转困难增加;政府权威降低,"一事一议"问题难以推行,公益事业发展缓慢。因此,税费改革后乡村关系呈现出乡对村的行政控制减弱,乡村关系趋于松散,乡村干部由原来的显性利益共同体转为隐性等新的特点。 相似文献
8.
Clay minerals and geochemistry of the bottom sediments in the northwestern East China Sea 总被引：1，自引：0，他引：1
Jeungsu YOUN Shouye YANG Yong Ahn PARK 《中国海洋湖沼学报》2007,25(3):235-246
Clay minerals of 34 sediments collected from the northwestern continental shelf of the East China Sea have been determined by X-ray diffraction analysis. The clay mineral distribution is mainly controlled by the sediment source and the dominant circulation pattern. The predominant clay mineral in our study area is illite comprising more than 67% of the whole clay fraction. The highest concentration of illite (>68%) is found in the southeastern offshore parts beyond the reach of terrigenous input from the Jeju Island. It means that these illites are largely transported by the Kuroshio Current from the South China Sea (SCS). Smectite is highly concentrated in the northwest middle part and in the outer-shelf mud patch. It seems to be due to the high supply of smectite transported from China where fine-grained sediments are discharged from modern and ancient Huanghe (Yellow) River. The relatively high abundant kaolinite is likely derived from the Changjiang (Yangtze) River via the Taiwan Warm Current. In contrast, large amounts of chlorite and high chlorite/kaolinite ratios occur in the northwestern area, reflecting the transportation by the Yellow Sea Coastal Current from the southern Yellow Sea. The discrimination diagrams clearly show that the sediments in the northwestern East China Sea are ultimately sourced from Chinese rivers, especially from the Huanghe River, whereas the sediment in the northeast part might come from the Jeju Island. The muddy sediments of the Changjiang River’s submerged delta have much lower 87Sr/86Sr ratios (0.716 2–0.718 0) than those of the Shandong Peninsular mud wedge (0.721 6–0.724 9), which are supposed to be originated from the Huanghe River, suggesting the distribution pattern of 87Sr/86Sr ratios as a new tracer to discriminate the provenance of shelf sediments in the study area. The 87Sr/86Sr ratios of the outer-shelf muddy sediments ranged from 0.7169 to 0.7216 in a wide range and was between those of the Huanghe River and Changjiang River sediments, suggesting multiple sources of the sediment in the area. 相似文献
9.
Wang Peilie 《中国海洋湖沼学报》1985,3(1):37-47
Minke whales caught in the Yellow Sea range from 4.16 m to 8.60 m in length with an average length of 6.93 m for the female
and 6.14 m for the male. Sex ratio of the female is 74.3%. The pregnancy ratio of all sexually matured females is 65.8%. The
minimum size of the pregnant whale observed is 6.60 m in length. Females having a body length of more than 7 m long are all
sexually matured.
According to the studies on the embryos obtained from the females caught in the northern Yellow Sea, there is only one breeding
season each year. Mating mostly occurs from July through September, and the length of pregnancy is ten to eleven months with
the peak of calving from May through July. Most females breed one calf each time, only two cases with twins. Sex ratio of
female fetus is 56.6%, and the newly born calf measures 250–270 cm in body length.
This paper was published in Chinese inOceanologia et Limnologia Sinica
13 (4): 338–345. 相似文献
10.
Seasonal and annual with stress fields over the Bohai Sea, the Yellow Sea and the East China Sea were computed from the wind
rose data compiled in the Climatic Atlas of Chinese Offshore Areas and North-west Pacific and published by the Ocean Press
in 1982. 684 wind roses in 2° latitude by 2° longitude boxes constructed from 278,815 wind reports are involved in the present
study. The computations are principally intended as a data source for further research. Some oceanographic consequences are
expounded on. 相似文献
11.
企鹅珍珠贝人工苗生长的初步观察 总被引：3，自引：0，他引：3
为了解企鹅珍珠贝生长规律，观察了壳高2.5～5.0mm的出池幼苗，按月测量其生长参数和成活率，以及环境因子。结果表明，企鹅珍珠贝生长最快的月份为7～11月和次年4～6月，壳长，壳高和壳宽月均增加量分别为3.8～13.0mm、4.7～11.2mm、2.3～3.8mm，月成活率97.8%～98.6%。企鹅珍珠贝生长最慢月份是11月至次年3月。 相似文献
12.
提取巴颜喀拉地块东部边界鲜水河断裂、龙门山断裂及边界附近西秦岭构造区跨断层灰色关联度指标曲线，根据1999~2007年、2009~2015年及2015~2017年GPS速度场数据计算所得的鲜水河断裂、龙门山断裂及塔藏断裂剖面变化，通过对比分析寻找地块边界断裂活动的共性特征。结果表明，2009年巴颜喀拉地块东部出现显著的SE向加速运动，之后数年一直维持这种高速特性，汶川8级地震的发生调整了该地区的应力状态，有利于芦山7级地震及九寨沟7级地震的发生；2015~2017年巴颜喀拉地块东部在维持高速运动和高应力状态基础上继续增速变化，地块边界鲜水河断裂2016~2017-07跨断层观测数据显示的显著拉张加速变化与九寨沟地震有一定关联，具中期背景性预测意义。 相似文献
13.
东太平洋赤道公海茎柔鱼生物学特性 总被引：1，自引：0，他引：1
根据2013年4~6月在赤道公海探捕期间采集茎柔鱼样本,研究赤道公海茎柔鱼渔业生物学特性。结果表明,不同性别、不同月份,茎柔鱼胴长和体质量组成不同。雌、雄性样本的胴长范围分别为93~495 mm和94~406 mm,优势胴长组分别为260~340 mm和240~320 mm,分别占样本总数72.53%和70.26%;雌、雄性样本体质量范围分别为25~3 900 g和33~2170 g,优势体质量组分别为400~1 200 g和200~1 000 g,分别占样本总数82.71%和87.82%。雌、雄性茎柔鱼净体质量比例分别介于31.69%~80.51%和37.05%~81.35%之间,平均值分别为60.45%和62.73%。协方差分析表明,茎柔鱼胴长与体质量、胴长与净体质量的生长均存在性别间差异,胴长与体质量的生长都最适合用幂函数表示,而胴长与净体质量的生长,雌、雄性样本分别最适合用幂函数和指数函数表示。不同月份茎柔鱼性别比例构成不同,4月、5月和6月性别比例分别为1.87∶1、1.61∶1和1.17∶1,全部样本的性别比例为1.61∶1。不同月份茎柔鱼性腺成熟度的组成不同。不同性别、不同月份间茎柔鱼胃含物等级组成存在差异。 相似文献
14.
TIAN Xu JIANG Zuzhou GAO Wei LIU Zhaoqing LIU Xiling FAN Ying QIN Shengjie JING Chunlei XU Yue LIU Baohua XU Fangjian 《中国海洋大学学报(英文版)》2019,(5)
The concentrations of rare earth elements(REEs) in the bulk sediment of Core X2, which was collected from southeastern Hainan Island, were analyzed to investigate the relative contributions of various provenance regions since mid-Holocene. The results show that sediments in Core X2 were primarily derived from Hainan Island with lesser amounts from Taiwan and limited input from the Pearl River. Based on the application of quantitative inversion to model the REE data, the average contributions of river materials from southeastern Hainan Island and southwestern Taiwan to the study area were 68% and 32%, respectively. Furthermore, starting at 4.0 kyr BP, the transport of fluvial sediments from Taiwan to the study region increased due to enhanced hydrodynamics in South China Sea(SCS). These results indicate that the contributions of mountain river materials from Hainan Island and Taiwan to the continental shelf of northern SCS are non-negligible. Furthermore, these results demonstrate that mountain rivers can play an important role in the material cycle of continental margins and may feature a greater impact than large river systems in specific continental shelf areas. 相似文献
15.
随着传统测绘产业向地理信息产业的转化 ,数字化成为测绘生产的主要技术手段 ,数字测绘产品占有越来越多的市场 ,并从产品形式、产品功能、产品服务等几个方面为测绘技术革命带来了新的生机 相似文献
16.
Studying the mechanical properties of the soil-root interface using the pullout test method 总被引：4，自引：0，他引：4
It is important to quantify the effect of the root diameter, the embedment length of the root and load speed on the soil-root interface mechanical properties for studying the root anchorage. The soilroot interface mechanical properties can be obtained through the pullout force and root slippage curve(F-S curve). About 120 Pinus tabulaeformis single roots whose diameters ranged from 1 mm to 10 mm divided into 6 groups based on different root embedment length(50 mm, 100 mm and 150 mm) and different load velocity(10 mm·min~(-1), 50 mm·min~(-1), 100 mm·min~(-1) and 300 mm·min~(-1)) were investigated using the pullout method. This study aims to explore the mechanical properties of the soil-root interface in the real conditions using the pullout test method. The results showed two kinds of pullout test failure modes during the experimental process: breakage failure and pullout failure. The results showed that the roots were easier to be broken when the root diameter was smaller or the loading speed was larger. The relationship between the maximum anchorage force and root diameter was linear and the linearly dependent coefficient(R~2) was larger than 0.85. The anchorage force increased with the root embedment length. An increase of 10%~(-1)5% for the maximumanchorage force was found when load speed increased from 10 to 300 mm.min~(-1). The mean peak slippage of the root was from 13.81 to 35.79 mm when the load velocity varied from 10 to 300 mm.min~(-1). The study will be helpful for the design of slopes reinforced by vegetation and in predicting risk of uprooting of trees, and will have practical benefits for understanding the mechanism of landslide. 相似文献
17.
Pacific water exits the Chukchi Sea shelf through Barrow Canyon in the east and Herald Canyon in the west, forming an eastward-directed shelfbreak boundary current that flows into the Beaufort Sea. Here we summarize the transformation that the Pacific water undergoes in the two canyons, and describe the characteristics and variability of the resulting shelfbreak jet, using recently collected summertime hydrographic data and a year-long mooting data set. In both canyons the northward-flowing Pacific winter water switches from the western to the eastern flank of the canyon, interacting with the northward-flowing summer water. In Barrow canyon the vorticity structure of the current is altered, while in Herald canyon a new water mass mode is created. In both instances hydraulic effects are believed to be partly responsible for the observed changes. The shelfl）reak jet that forms from the canyon outflows has distinct seasonal configurations, from a bottom-intensified flow carrying cold, dense Pacific water in spring, to a surface-intensified current advecting warm, buoyant water in summer. The current also varies significantly on short timescales, from less than a day to a week. In fall and winter much of this mesoscale variability is driven by storm events, whose easterly winds reverse the current and cause upwelling. Different types of eddies are spawned from the current, which are characterized here using hydrographic and satellite data. 相似文献
18.
On-site monitoring is very important for understanding formation mechanisms of frost hazards frequently occurring in pipeline foundation soils and for designing and deploying according mitigative measures in permafrost regions.Significant thaw subsidence of ground surfaces along the ChinaRussia Crude Oil Pipeline(CRCOP) from Mo'he to Daqing,Heilongjiang Province,Northeast China have been observed at some segments underlain by ice-rich warm(1.0°C) permafrost since the official operation in January 2011.Recent monitoring results of the thermal states of foundation soils at the kilometer post(KP) 304 site along the CRCOP are presented in this paper.The results indicate that during the period from 2012 to 2014,shallow soils(at the depths from0.8 to 4.0 m from ground surface) has warmed by approximately 1.0°C in the lateral range of 1.2 to 2.1 maway from the pipeline axis,and deeper permafrost(such as at the depth of 15 m,or the depth of zero annual amplitude of ground temperatures) by 0.08°C per year 4 m away from the pipe axis,and 0.07°C per year 5 m away from the pipeline axis.The results indicate an all-season talik has developed around and along the CRCOP.The thaw bulb,with a faster lateral expansion(compared with the vertical growth),enlarges in summer and shrinks in winter.This research will provide important references and bases for evaluating thermal influences of warm pipeline on permafrost and for design,construction,operation and maintenance of pipelines in permafrost regions. 相似文献
19.
Characteristics and causes of the preconsolidation stress of soils in the Yellow River Delta 总被引：1，自引：0，他引：1
20.
Via the valuable opportunity of the Three Gorges Reservoir (TGR) 135-m filling in June 2003, the Yangtze discharge and suspended sediment concentration (SSC) entering the estuary during the period from 15 May to 15 July 2003 were analyzed to examine the instant effects of the filling on them. The Yangtze discharge and SSC entering the estuary in the periods before, during and after the filling clearly indicated three phases: 1) the pre-storage phase characterized by natural conditions, in which the SSC incr... 相似文献