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1.
3,5-Br2-PADAP在pH为3.2的甲酸-甲酸钠缓冲溶液中能与Bi(Ⅲ)、Cu(Ⅱ)、Co(Ⅱ)和Ni(Ⅱ)形成稳定的络合物。研究了Bi(Ⅲ)、Cu(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ)-3,5-Br2-PADAP体系的显色条件,用偏最小二乘法处理所得数据,从而建立了分光光度法同时测定Bi(Ⅲ)、Cu(Ⅱ)、Co(Ⅱ)和Ni(Ⅱ)的方法。方法简便可靠,灵敏度高,选择性好。  相似文献   

2.
1 INTRODUCTIONTherateoffoodconsumptionoffishfedadlibitumisregardedasthemaximumrateoffoodconsumption(Cmax) (Woottonetal.,1 980 ) .SeveralfactorsthatinfluenceCmaxincludingbodyweight (Liuetal.,1 998) ,watertemperature (Liuetal.,1 998) ,dis solvedoxygen (Vivekanandan ,1 977) ,salinity (ZanuyandCarrillo ,1 985 ) ,andphotoperiod (Grossetal.,1 965 ) ,werereported .Bodysizeandwatertemperaturewereregardedastwoofthemostimportantfactors,andhadreceivedmostattention (Elliott,1 979;Woottonetal.,1 …  相似文献   

3.
AdvisorsDingDewen(丁德文 ) MaFuchen(马福臣 )LiuDongsheng(刘东生 ) LiuZhenxing(刘振兴 )LiuGuangding(刘光鼎 ) SunJiulin(孙九林 )XuHouze(许厚泽 )LiDeren(李德仁 )LiTingdong(李廷栋 ) SuJilan(苏纪兰 )WangPinxian(汪品先 ) ZhouXiuji(周秀骥 )OuyangZiyuan(欧阳自远 ) QinDahe(秦大河 )YuanYeli(袁业立 )ChaoJiping(巢纪平 )ChiefEditorDongZhaoqian(董兆乾 )Vice-chiefEditorsBianLingen(卞林根 ) SunSong(孙 松 ) LiuXiaohan(刘小汉 )ZhangZhanhai(张占海 )YangHuigen杨惠根 (常务 )MembersBianLingen(卞…  相似文献   

4.
设k∈N,f(z)为复平面上的超越亚纯函数,φ(z)、ak-1(z),…,a0(z)为f(z)的小函数,且φ(z)≠0.置P(f)(z)=f(k)(z) ak-1(z),k-1((z) … a1(z)f'(z) a0f(z),且P(f)(z)不恒为常数.当k≤4时,满足Nk)(r,1/f)=S(r,f);k≥5时,满足N4)(r,1/f)=S(r,f),则T(r,f)<20-N(r,1/φfP-1) S(r,f).  相似文献   

5.
罗非鱼4个选育群体遗传结构SSR分析   总被引:2,自引:0,他引:2  
采用SSR分子标记分析了吉富品系罗非鱼的两个家系(GF1和GF2)以及奥利亚罗非鱼(Fo)和奥本尼罗罗非鱼(Fn)群体的遗传结构。结果显示,扩增后等位基因数为3~8个,随引物不同而异,14对引物共扩增60个等位基因,扩增片断大小在102~267 bp之间。微卫星分析表明,奥本尼罗罗非鱼(Fn)的平均观测杂合度(0.764 3)和平均期望杂合度(0.519 6)均最高,吉富尼罗罗非鱼(GF1)平均多态信息含量(0.419 5)最高;吉富尼罗罗非鱼(GF2)平均观测杂合度(0.614 2),奥利亚罗非鱼(Fo)的平均期望观测度(0.446 6)、平均多态信息含量(0.359 2)最低;因此,吉富鱼(GF1)的遗传多样性最高,奥利亚的遗传多样性最低。Hardy-Weinberg平衡遗传偏离指数(D)奥利亚(Fo)和尼罗(Fn)(0.463 4和0.478 9)明显高于吉富的两家系(0.234 1和0.250 0)。Fo与GF2间遗传距离(0.477 0)最大;而GF1和GF2间的遗传距离(0.302 7)最小,遗传相似系数(0.607 3)最大,可推断新一代吉富罗非鱼与本地选育群体有相对较远的亲缘关系,更具杂种优势。  相似文献   

6.
Trare amounts of benzene hydrocarbons obtained in Jiaozhou Bay (Qindao) were enriched bysorption on a GDX-102 column and eluted by carbon disulfide. The eluted was concenttaled and then de-temened by capillary column gas cbornatognphy.The contents of virious kinds of benzene hydrocarbons in Jiaozhou Bay coastal water were benzene(22.3-141.6)× 10~(-9)g/L, toluate (15.2-94.0) × 10~(-9) g/L, ethyl benzene(11.8-85.1)×10~(-9) g/L, p -xylene(15.2-78.5) ×10(-9) g/L, m-xylene (10.9-79.4) ×10(-9) g/L, o -xylene (12.4-80.1) x ×10(-9)g/L; iso-propyl(8.4- 73.1) x ×10(-9)g/L, n -propyl (6.9-76.4) ×10(-9) g/L, 1, 3, 5-trimethylbenzene (10.9- 35.9)×10(-9) g/L, 1,2, 4-trimethybenzene (10.0- 38.0)×10(-9) g/L, n - butydriare (8. 1 - 34.6) ×10(-9)g/L. The recovery of benzenehydrocarbons was (85.1 -95.6)%.  相似文献   

7.
1 IntroductionManymeteorologistsandoceanographerspaidmuchattentiontothestudyofthemechanismofENSOformanyyears,suchasBjerknes(1 966) ,Wyrtki(1 975) ,McCreary(1 983 ) ,Philander(1 984) ,ZhangandChao(1 993 )andMcCPhaden(1 998)havemadegreatdevelopmentinthestudyofENSO .Especiallyinthe 1 990’s,withtheincreasingofthedatainthedeepocean ,thesomeonearguedthattheENSOepisodehadcloserelation shipwiththeeasterntransportationoftheanomalousseasurfacetemperatureinthewestPacific(LiandMu 1 999;Huang 2…  相似文献   

8.
(Quarterly, since 1982) Editor-in-Chief Dunxin HU (China) Advisers Shupeng CHEN (China) Ruiyu LIU (China) SLihjine nJgIAchNaGn g( CWhEinNa )( China) JLiiaannkjuann gY EL I(UC (hCinhain) a) Members of Editorial Board Ping CHANG (USA) Chen-Tung Arthur CHEN …  相似文献   

9.
对于正整数a ,设S(a)是Smarandache函数。证明了 :方程S(1·2 ) +S(2·3) +… +S(x(x +1) ) =S(x(x +1) (x +2 ) /3)仅有正整数解x =1。  相似文献   

10.
INTRODUCTIONBrownalgaepolyphenol (BAP)isadistinctivenaturalproduct,anactiveorganicmatterre leasedfromnormalgrowingbrownalgaeintoseawater.TheBAPoutputfromthelivingbrownalgaeis 1g (m2 ·d) (Craigieetal.,1 964 ) .About3 7%ofdissolvedorganicmatter(DOM)inseawateralongshoreisthesecretionfromseaweedcells,andcanreach 70 %oftotalDOMinseawaterifor ganicmatterreleasedbydeadalgaeisincluded (Raganetal.,1 979) .BAP (mainlycomprisingtheyellowmatter)inseawateralongshore ,canreach 2 .5mg L (Rashida…  相似文献   

11.
The beach studied in this paper spans a length of 51 km and is one of several long sandy beaches in the southern Bohai Strait. Due to the obstruction of islands in the northeast and the influence of the underwater topography, the wave environment in the offshore area is complex; beach types and sediment transport characteristics vary along different coasts. The coastlines extracted from six aerial photographs in different years were compared to demonstrate the evolving features. Seven typical beach profiles were selected to study the lateral beach variation characteristics. Continuous wind and wave observation data from Beihuangcheng ocean station during 2009 were employed for the hindcast of the local wave environment using a regional spectral wave model. Then the results of the wave hindcast were incorporated into the LITDRIFT model to compute the sediment transport rates and directions along the coasts and analyze the longshore sand movement. The results show that the coastline evolution of sand beaches in the southern Bohai Strait has spatial and temporal variations and the coast can be divided into four typical regions. Region(I), the north coast of Qimudao, is a slightly eroded and dissipative beach with a large sediment transport rate; Region(II), the southwest coast of Gangluan Port, is a slightly deposited and dissipative beach with moderate sediment transport rate; Region(III), in the central area, is a beach that is gradually transformed from a slightly eroded dissipative beach to a moderately or slightly strong eroded bar-trough beach from west to east with a relatively moderate sediment transport rate. Region(IV), on the east coast, is a strongly eroded and reflective beach with a weak sediment transport rate. The wave conditions exhibit an increasing trend from west to east in the offshore area. The distribution of the wave-induced current inside the wave breaking region and the littoral sediment transport in the nearshore region exhibit a gradual weakening tendency from west to east, which is opposite to the trend of the wave conditions outside the breaking region. The presence of submerged shoal(Dengzhou Shoal), deep trough(Dengzhou Channel), islands and irregular topography influnces the wave climate, beach types, wave-induced current features, littoral sediment transport trends and coastline evolution patterns in the southern Bohai Strait. Human activities, such as the sand exploitation of Dengzhou Shoal and other coastal engineering projects, also influence the beach morphology and coastline evolution.  相似文献   

12.
The purpose of this study is to investigate the control function and mechanisms of natural river notches. Physical and numerical experiments are analyzed in this study for two representative types of sediment events: high intensity and short duration Type A sediment disaster events, and low intensity and long duration Type B moderate non-disaster events. Two dimensionless parameters, sediment trapping rate and reduction rate of peak sediment transport, are defined to evaluate the sediment control function of river notches. Study results indicate that the contraction ratio of the notch has a significant influence on sediment control function, with high contraction ratios resulting in both high sediment-trapping and high reduction rates. River notches provide better sediment control during Type A events than Type B events. The sediment control mechanism of river notches is the result of multiple interactions among river flow, sediment transport, and riverbed variation. Analysis of these interactions supports the significant protection role of river notches on sediment control for disaster events  相似文献   

13.
Based on the measured data, suspended sediment concentration, surface sediment grain size, current and waves, the sediment transport mechanisms and pathways in the Phoenix Island area were analyzed using methods of flux decomposition and Grain Size Trend Analysis (GSTA). The results show that net suspended sediment is mainly transported by average current, Stokes drift, and gravitational circulation. The transport direction of suspended sediment is varying and basically following the direction of residual tidal currents. Surface sediment transport pathways are primarily parallel to the coastline along with two convergent centers. Waves and longshore currents have a significant influence on sediment transport, but the influence is limited due to a steep and deep underwater bank. Tidal current is the main controlling factor for sediment transport, especially in the deep water area. Neither suspended nor surface sediment is transported towards the southwest. The South Shandong Coastal Current (SSCC) has little effect on sediment transport processes in the nearshore area of Phoenix Island.  相似文献   

14.
Breakwaters can be used as artificial headlands in beach nourishment to mitigate coastal erosion. Longfengtou Beach, located on the southwest coast of Haitan Bay facing the Taiwan Strait on the northeast, suffers severe erosion, where the monsoon causes significant season hydrodynamic variations. Headland breakwaters are intended to be employed to mitigate coastal erosion. A 2D sediment transport model is established using MIKE21 based on current-wave coupling and calibrated by measured data. Summer and winter wave conditions are chosen as characteristic weak and strong waves respectively. The numerical results of suspended sediment concentration and seasonal morphological evolution are compared under the conditions with and without the headland breakwaters. Sediment transport in summer can be regarded as mainly determined by current field, while in winter wave effect is strong enough to change current field. The northern breakwater, nearly perpendicular to the ebb current direction, obstructs the currents and decreases velocity of the ebb currents, and confines the water carrying sediments within the protection area during the flood period. The southern breakwater also breaks the waves in advance and significantly reduces the hydrodynamic effects during the flood period and maintains high suspended sediment concentration in the protection area. In general, two headland breakwaters decrease the erosion near the beach and enlarge the deposition area, which play a significant role in prevention of sediment loss in nearshore area and mitigate coastal erosion.  相似文献   

15.
Equilibrium coastal profiles: II. Evidence from EOF analysis   总被引:1,自引:0,他引:1  
The validity of the concept of coastal equilibrium depends upon a proof of the existence of equilibrium. In addition, the methods of calculating the actual equilibrium profile and the response time are required. This study evaluates equilibrium conditions using evidence from EOF (empirical orthogonal function) analysis of the coastal profile data (bed slopes and associated elevations) obtained from Poole and Christchurch Bays, southern England. The preliminary results show that the largest eigenvalue is much greater than the other eigenvalues and the temporally-related eigenfunction is stationary; this observation implies the existence of equilibrium. Further, the spatially-related eigenfunction associated with the largest eigenvalue is used to calculate the actual beach profile at equilibrium. Although the temporal eigenfunction may fluctuate, it recovers rapidly, indicating that the response time is short. However, further studies are required to determine the response time accurately. Contribution No 3335 from the Institute of Oceanology, Chinese Acodemy of Sciences. Project supported by the SCOPAC (UK) and the CAS (through the “Hundred Talent Programme”, No. A10970203)  相似文献   

16.
Studies on land loss in Tuvalu reveal the following findings. Although both sea level rise and coastal erosion can cause land loss in the tropic Pacific oceanic islands, their mechanisms are different. When sea level rises, the low elevation coastal zone submerges and the erosion datum plane rises, the beach process progresses normally as always, resulting in no beach sediment coarsening. When the sea level is stable, coastal erosion removes finer sediment from reef flat, beach and land, resulting in beach sediment coarsening. The human-induced coastal erosion in the tropic Pacific oceanic islands has the following features. 1) Erosion occurs or intensifies immediately after inappropriate human activities. 2) It occurs near the places having human activities and places related to the above places in sediment supply. 3) It often occurs on original prograding or stable coasts (on lagoon coasts for atolls) because there are more coastal engineering projects and other human activities on such coasts. 4) It is chronic, covering a long period of time. The coastal geological events in Tuvalu islands do not accord with the features resulted from sea level rise but do accord with the features resulted from coastal erosion, particularly from human-induced erosion. The land loss in Tuvalu is mainly caused by inappropriate human activities including coastal engineering and aggregate mining, and partly caused by cyclones. Moreover, all recent measurements (satellite altimetry,thermosteric sea level data and tide observations) so far have not been able to verify any sea level rise around Tuvalu islands.  相似文献   

17.
As a very important component of a coastal system,tidal flats come to be a focus of the studies on land-ocean interaction in the coastal zone because those areas are subjected to intense human activities and are highly sensitive to the global change.The Quanzhou Bay,located along the middle part of Fujian coast of China,covers about 136.4km2,and the area of coastal wetland in the entire bay from intertidal to subtidal with 6m of water depth accounts for 96% of the total area.Seven short cores were collected and divided in situ with the interval of 5cm on the coastal wetlands of Quanzhou Bay on April 19,2006.The sediment samples were scattered and the grain sizes were measured by using Mastersizer 2000.Human beings' activities on tidal flat have disturbed the vertical distribution of sediments in stratigraphic sequence and accelerated the sedimentation rates.Grain size analysis results show that the grain size diameters increase and sediment becomes worse sorted towards the sea under the strong human disturbance;Spartina alterniflora can play a role of trapping the fine sediment;but near the bank,the sediment becomes coarse and there are two peak values on frequency curve influenced by the sandpile.The trough formed by human activities along the coastline changes the transport path of water and suspended sediment.The sediments are transported through the trough and deposit in it during the flood;the ebb flow is retarded by the flow output through the adjacent trough,and the deposited sediment can not be re-suspended;then,the sedimentation rate increases.In situ observation show that the sedimentation rate is about 8-10cm/yr.  相似文献   

18.
滨海平原弱透水层广布且多赋存古咸水,其盐度分布及运移过程深刻影响着含水层地下水的演变,却得到甚少关注。采集了江苏滨海区7个浅层钻孔弱透水层原状样品,压榨法收集孔隙水。利用孔隙水天然示踪剂ρ(Cl-),ρ(Br-)剖面和数值模拟分析了弱透水层孔隙水盐度特征和运移机制。得出浅层孔隙水ρ(Cl-)垂向剖面存在2个趋势:①峰值在表层,沿深度逐渐下降;②峰值在深度25m左右,向两端浓度降低。孔隙水ρ(Cl-)为486.2~38 036.7 mg/L,Cl/Br比值为72~360(均值241)。ρ(Cl-)与Cl/Br比值关系及剖面分布说明孔隙咸水为海相成因,来自于全新世海侵时期的古海水,并受到后期淡水的稀释。弱透水层孔隙水一维垂向运移数值模型表明海侵-海退事件控制了海岸带弱透水层孔隙水的盐度演变,全新世古海水仍封存在沉积物中,更新世时期的海水已被驱替。孔隙水运移以扩散为主,垂向运移速率为0.43~15.8 mm/Ma。在相对高渗透性的粉砂地层中,可能还受到侧向对流的影响。弱透水层中古海咸水的重新分布,尤其在地下水超采条件下,可能成为地下水的重要咸化来源。   相似文献   

19.
ImODUcrIONGroundwaterwthAnneralimtionofmorethan5OgA(about5"Be')"iscalledunder-groundbrine.ltbelongstoevaporationoredepositinliquidstateandisantwortantrnaterialsourceforsaltonkingandthechewhcalindustry.QuatemarylittoralfadesundergroundbrinewasstoredinthelittoralsoneandhadtwobasictypesofgenesisenvironmentflittoralplaincoastenvironmentcharacterindbythecoastalongLaichouBay,andembayedcoastenvironmentcharaCterindbythecoastalzoneofQingdao.TheauthorresearchedthebrineintheLaizhoubaycoastareainthe…  相似文献   

20.
Over the last several decades,various sediment transport capacity formulations have been used by geomorphologists and engineers to calculate fluvial morphological changes.However,it remains poorly understood if the adaptation to capacity could be fulfilled instantly in response to differing inflow discharges and sediment supplies,and thus if the calculation of morphological changes in rivers based on the assumed capacity status is fully justified.Here we present a numerical investigation on this issue.The distance required for sediment transport to adapt to capacity(i.e.,adaptation-to-capacity length) of both bed load and suspended sediment transport is computationally studied using a coupled shallow water hydrodynamic model,in line with varied inlet sediment concentrations.It is found that the adaptation-to-capacity length generally decreases as the Rouse number increases,irrespective of whether the inlet sediment concentration increases or reduces.For cases with vanishing inlet sediment concentration a unified relationship is found between the adaptation-to-capacity length and the Rouse number.Quantitatively,the adaptation-to-capacity length of bed load sediment is limited to tens of times of the flow depth,whilst that of suspended sediment increases substantially with decreasing Rouse number and can be up to hundreds of times of the flow depth.The present finding concurs that bed load sediment transport can adapt to capacity much more rapidly than suspended sediment transport,and it facilitates a quantitative criterion on which the applicability of bed load or suspended sediment transport capacity for natural rivers can be readily assessed.  相似文献   

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