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1.
The Al—basic sacrificial anode is widely used to protect steel construction from corrosion in seawater, but is not suitable for protecting steel in freshwater. In the estuary area, seawater and freshwater mix and different seawater salinity can be formed in different mixing sites between freshwater and seawater. Based on the requirements of the Shengli Petroleum Administrative Bureau of China, the effect of seawater salinity on electrochemical properties of Al—basic anode was studied under laboratory conditions by the method given in National Standard GB 4948-85 (China Starndard Bureau, 1985). No obvious effect was found when seawater salinity was 30 to 10, but obvious effect on anodic open circuit potential, closed circuit potential and current efficiency was found when seawater salinity was 5. These values are lower than those given in the National Standard. Contribution No. 2681 from the Institute of Oceanology, Chinese Academy of Sciences. This study is a major project (Ky85-11-5) and a key project (A14920416) of the Chinese Academy of Sciences, and also received support from the Shengli Oil Field.  相似文献   

2.
INTRODUCTIONTheHuangheRiverwellknownworldwideforitshighsedimentdischargeisChina’ssecondlargestriver,whoserunoffismainlysuppliedbyprecipitationovertheupperreaches.However,thematerialfromsoilerosionintheLoessPlateauinthemiddlereachesisamajorcontributort…  相似文献   

3.
The survey in the, Huanghe River estuary indicated that the 85 fish species found there comprised three faunal elements: warm-water species (29.4%), warm-temperate species (55.3%) and cpld-temperate species. (15.3%). The seasonal changes of fish species, density and bipmass are obvious. The total biomass is highest (7699t) in August and lowest(489 t) in January. Setipinna taty has mean density of 9278 indiv/km2, and is the most important species constituting 25.5% of the total weight of fish caught. Trichiurus haumela was a dominant species in the 1950s, but no one was caught in this survey. There were obvious changes of the dominant fish species during the recent three decades. The demersal fish biomass has dropped greatly to only 1/10 in over 50 years since 1930.  相似文献   

4.
本文首先给出了守恒系统与耗散系统的性质与运动规律和开放的耗散体系的自组织演化行为,进而给出了由大区域构造网络所组成的蕴震系统是一个开放的耗散系统的论证,并分析了该系统的自组织行为和时空演化的吸引子。以京津唐地区为例,使用单序列的重建复杂系统动力学方法(时间域)和多时间序列的复杂系统动力学分析方法(空间域),由大灰厂形变水准资料的计算得出大地震前具有减熵、降维和Lyapunov指数上升的变化趋势,由该地区12个形变台站组成的前兆场的空间分布的分析得到一个2.9维的分形分布、4~5年的可预报期限(K_1=0.0885)和一个正的Lyapunov指数(0.09864)。这表明系统的时空分布沦入一个浑沌吸引子中,具有分形结构和自组织演化行为以及临界失稳的共性。  相似文献   

5.
Based on Pb technique, sedimentation rates of 11 cores collected from the Huanghe River estuary were determined. CaCO3 distribution of 4 cores chosen from among these was measured. Profiles of 210Pb in the cores showed that the distribution of 210Pb activity decayed with depth, appeared in stages and in more than one segment. The sedimentation rates,210Pb and CaCO3 data have similar distribution trend in the 4 cores. Jhe profiles of Pb and CaCO3 were used to study sedimentation in -tensity, transportation trend of material and sedimentation features in the coring area.  相似文献   

6.
IMRODUcTlONThe577km1ongMinjiangRiver,thelongestriverinFujianProvinceofChina,hasa6O992km2drainagebasin.Thewaterdischargeislarge(meaninyearsis198Om/s).TheannualrunofffromtheMinjiangRiveris5.84xlOlom,WhichismorethanthatoftheHuangheRiver,andranksthirdintheannualrunoffofmaorChineseriversWhang,l994).SimdentnutrientSfromtheMinjiangRivertotheseaisanarisa-ryconditionforthefonnationandcontinuingexistenceoftheMindongFisheryGroundandtheMihahongFisheryGround.Inthendingareaofriverwaterwithseaw…  相似文献   

7.
The effects of using different types of glass fiber filters (GF/F, GF/C) and of sample treatments evaluated. Studies on the variation of suspended matter (SM) and particulate organic carbon (POC) showed that: 1) the transversal and day to night variations are important and must be taken into account in order to get a corrcet river flux; 2) no regular seasonal variations of SM and POC observed, as they are controlled essentially by the climatological, hydrologic, physiochernical, biological, and geological conditions of the drainage area.  相似文献   

8.
丹江口水库诱发地震研究   总被引:2,自引:0,他引:2  
丹江口水库由汉江、丹江两个库段组成。在丹库的峡谷灰岩地带 ,断裂、节理发育 ,利于水的渗透和循环。 196 7年 11月蓄水后 ,随水位的增加 ,地震活动增加 ,且震级由Ms<2 .5上升到Ms =4.7,并在丹库的峡谷附近形成北北西方向延伸的 3个地震密集区。地震频度、强度与水位 (库容 )变化有一定的相关性。预测二期工程蓄水后 ,仍将产生诱发地震 ,其最大强度为Ms≤ 5 .0。  相似文献   

9.
Effect of salinity on survival,feeding behavior and growth of juvenile swimming crab P ortunus trituberculatus was investigated under 5 salinity levels of 5,10,20,30 and 40. The results show that the crab juveniles fed 2 or 3 times at the salinity 20 and 30,each lasted for about 25 minutes,for a total feeding time of 73.2±22.65 minutes per day. At these salinities,there were significantly higher in the frequency of feeding and in total feeding time than those at lower salinities of 5 and 10. All crab juveniles moulted when reared at a salinity of 20 during the 5 days duration of the experiment,which is significantly higher than those at other salinities. All juveniles survived at salinity 20,and the survivorship was not significantly different from that at 30,but was signif icantly higher than those at other salinities. The crab juveniles reared at a salinity of 20 had the highest value of food ration of 0.190 8±0.011 3 g/g BW,average body weight gain of 0.796±0.128 g,gain rate of 87%–96%,and food conversion ratio of 1.20±0.09. There was no significant difference in the values found between 20 and 30 but these values were significantly lower than that at the other salinities( P 0.05). Highest activities of digestive enzymes(Amylase,Protease,Lipase) and lowest activities of protective enzymes(SOD,PO,CAT) were also obtained on crab juveniles reared at salinity of 20.  相似文献   

10.
厦门地震台重力仪同震响应特征分析   总被引:1,自引:1,他引:0  
2007年9月,印度尼西亚发生8次强震,厦门地震台的重力仪都有同震响应。从面波延迟时间、最大变形幅度、同震持续时间3个方面研究了8次强震的同震响应特征。  相似文献   

11.
南昌地震台钻孔应变同震响应分析   总被引:1,自引:1,他引:1  
通过总结2007年5月以来南昌地震台TJ-2钻孔应变仪的同震效应,并与同期中国地震台网(CSN)提供的全球大震目录中的数据进行对比分析,绘出了震级与震中距的对数关系图,得出南昌地震台体应变仪的映震能力的表达式近似为Ms=1.381gD+ 1.1.  相似文献   

12.
����̨����ǰ���쳣����   总被引:4,自引:3,他引:1  
?????????????2004??2007??????????????????????????????????SS??Y????????EW??????2007?????????????????????????仯????????з???????????????????仯????ε?????????????????????????????????????  相似文献   

13.
INTRODUCTIONThes0uthembayscallop,AmpeandiansconamtaSay,isanAmpenirradiansInrnaforsouthamsubepedesdistributingalongthecoastSfromNorthCarolinat0Florida,andisanirnPohantshellfishforfisherieSinthesouthrmU.S.A.,butthere-sonisdmingduetoexanivecapture.ThesouthemsubspedeswasfuStintIDdutalinl99lintoChinabytheInstituteofdrinology,ChineSeAcadeInyofSdenas,andshowedwonderfulprospan,althoughthedeveopmentalbiol0gy,espedllytheeffedofboortantenvirDnmentalfactors(forexamPlesandtyorternPeratwonthis…  相似文献   

14.
INTRODUCTIONInrecentyears,co culture (integratedculture )ofmarinespecies (algaeandanimals)hasreceivedgreatattention .Inco culturesystemthealgaeactivelyuptakeCO2 andthemetabolicwastes(suchasNH4 +,NO2 - ,NO3- etc)asnutrientsources,andreleaseO2 tothesurroundingenviron …  相似文献   

15.
陕西蟒岭马河地区宽坪群多期褶皱变形   总被引:1,自引:0,他引:1  
据面理置换、小褶皱叠加、线理构造,以及对大中型构造的分析,再结合原生沉积构造和构造几何学分析,确定马河地区宽坪群经历了至少三期叠加变形.第一期为区域性挤压的紧闭平卧褶皱,第二期为穹窿状或长垣状褶皱.第三期为南北向开阔宽缓褶皱。查清构造为正确建立层序提供了依据.  相似文献   

16.
河口捕获平均全长2.5cm的天然花鲈苗种,分二阶段进行培育。第一阶段是流水淡化驯养:包括淡化、暂养和驯饵;第二阶段是分级培育,每隔4~6d分筛分级一次,直至4~6cm的鱼种。试验总成活率是55%。  相似文献   

17.
???ü???GNSS????10??????????????????GPS????????????????????????仯???μ????????仯???????????????????????????仯????????????????????????????????С?????????м?????????п??????Ч?????????????????????????????????????????????  相似文献   

18.
通过对武汉台超导重力仪9年多连续观测的重力长期变化资料分析,得到长周期重力潮汐参数、该频段气压回归因子C、极移重力效应因子P和长周期气压回归因子C1分别为:C:-0.383(±0.014)×10-8m·s-2/100Pa;Mm:1.1173(±0.0720),-1°.1787(±3°.6943);Mf:1.1432(±0.0484),5°.2235(±2°.4253);Mtm:1.2276(±0.2245),-17°.5648(±10°.4758);C1:-0.312(±0.015)×10-8m·s-2/100Pa;P:1.9047(±0.0695).重力长期变化在Chandler周期附近的振幅约为3.26×10-8m·s-2。  相似文献   

19.
强降水对厦门地震台伸缩仪的影响   总被引:4,自引:0,他引:4  
对厦门地震台伸缩仪趋势变化中出现的一些异常现象的研究表明,其异常并不是前兆异常,而是强降水的影响。  相似文献   

20.
̩��̨��ײ�Ӧ��۲��ʵ�ر궨   总被引:2,自引:2,他引:2  
????????????????????????????????????????????????????峱???????????????????????·??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????仯?????????????????????ν?????????  相似文献   

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