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由于采挖贝壳、城市建设和修建养殖池,位于河北省黄骅古贝壳堤自然保护区内沿海岸的岐口—狼驼子贝壳堤已经不复存在,挽救已经不可能。山东省境内滨州贝壳堤岛与湿地自然保护区(国家级)内,在贝壳堤几十米后修建了养殖池。养殖池防护堤阻挡潮水向后漫溢,波浪作用在此增强。在波浪作用下贝壳堤已经遭到破坏(贝壳堤变低,贝壳堤前向海一侧受到侵蚀,将贝壳堤下伏层暴露出来)。如果要挽救这里的贝壳堤必须拆除贝壳堤后面的养殖池。 相似文献
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天津市古贝壳堤是距今5000年～500年间形成的,有“天然博物馆”之称,具有重要的科学价值。为了更好地保护这一极为珍贵的海洋遗迹,天津市将建设集保护、科研、旅游为一体的古贝壳堤展示中心。 古贝壳堤是“天津古海岸与湿地国家级自然保护区”的重要组成部分,位于天津滨海平原东部地区,分布有4道基本平行于现代海岸的贝壳堤,是由古代的潮汐、风浪将近海海底贝壳搬运堆积而成的。天津贝壳堤是世界三大贝壳堤之一 相似文献
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黄河三角洲北部贝壳堤岛的近期演变 总被引：2，自引：0，他引：2
通过不同年代地形图、卫星影像的对比及野外实地测量等,综合分析了黄河三角洲北部开敞型和潮沟型两类贝壳堤岛近50年来的数量和面积变化及其演化特征。结果表明,该区两类贝壳堤岛自20世纪50年代以来在自然和人为因素的共同作用下发生了明显的变化,但其演化特征因岛屿成因的类型差异而各不相同。目前,该区贝壳堤岛群逐渐萎缩,人类活动已成为影响三角洲北部两类贝壳堤岛发育演变的主导因素,特别是潮沟型贝壳堤岛,基本上结束了自然演化的历史,呈现出新的演化特征。 相似文献
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从保护对象及其生境的保护与管理角度出发,构建了基于概率和损失度的海洋保护区生态风险的综合评价方法。以滨州贝壳堤岛与湿地自然保护区为例,通过历史数据、遥感资料分析,筛选风暴潮、海岸侵蚀、海水污染、围填海、海冰、溢油等6种风险源,利用层次分析法确定权重并计算综合风险概率;根据贝壳堤、滩涂、养殖池塘等9种生境的自然生态、社会经济属性及生境的脆弱度,计算各生境的综合损失度;在地理信息系统(GIS)技术支持下,完成保护区生态风险的综合评价,对不同级别的风险区提出管理对策。对发展我国海洋保护区生态风险评价方法以及保护区范围科学选划调整等管理工作都有参考价值。 相似文献
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“天津古海岸与湿地国家级自然保护区”是１９９２年１０月国务院批准建立的国家级海洋类型自然保护区，它是在市政府１９８４年１２月批准建立的“贝壳堤市级自然保护区”的基础上扩展、升级而成的。保护对象由贝壳堤、牡蛎滩和七里海湿地生态系统，是古海岸变迁的极其珍... 相似文献
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《海洋地质与第四纪地质》2015,(6)
渤海湾西南岸大口河口至马颊河口一线分布着大口河岛、高坨子、棘家堡子和汪子岛等贝壳堤(岛)。以2003年10月10—12日发生的50年一遇的温带风暴潮为动力条件,结合对历史文献、海图、卫星影像等资料的分析,利用FVCOM和SWAN数值模式,耦合模拟了黄河废弃三角洲不同时期代表性岸线形态约束下贝壳堤近岸的波浪、潮流等动力响应特征。贝壳堤的规模、形态、分布等受特殊的岸线形态、海滩物质组成以及由ENE、NE强风驱动的风暴潮动力场等所控制。由于黄骅港和滨州港超长防波堤的掩护作用,在同等风暴潮强度下,贝壳堤近岸的潮位、流速和波高均有所减小,有利于贝壳堤的加积和稳定性。 相似文献
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定量分析敏感资源环境遭受突发性溢油事故的污染风险,对加强海洋溢油风险管理和应急响应具有现实意义。通过参考国内外现有研究成果,构建了溢油随机情景模拟统计方法,并利用GIS技术实现数据管理及可视化分析。考虑到海洋保护区是典型生物多样性和生态环境保护的敏感区域,以滨州贝壳堤岛与湿地国家级自然保护区为例进行案例研究。首先根据对保护区附近的黄骅港、滨州港海港码头、进港航道、锚地及埕北油田石油平台等溢油风险源的分析,选取3个代表性泄漏地点。然后在经验证的潮流场模拟数据和2004-2005年风玫瑰图数据基础上,对每个地点分别进行450次随机溢油事故情景(即不同泄漏时间、风速风向、潮流场等)的模拟计算。统计结果显示,全年所有风向条件下保护区遭受以上泄漏地点的最大溢油污染概率分别为22.9%、9.7%、3.0%,海面油膜最快到达时间分别为2 h、5 h、40 h。与典型情景模拟法的比较可知,随机情景模拟法是前者的重要补充,能够弥补大量遗漏的事故情景,有助于更客观全面地分析与评价海洋保护区遭受溢油事故的污染风险。 相似文献
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《海洋地质前沿》2001,17(9)
为搞清楚黄河三角洲的发育以及黄河三角洲进积和贝壳堤形成的关系 , 在黄河三角洲两个站位上打了钻 . 因为岩心采取率的原因 , H9601站位打了两个紧相邻的钻孔 (Ⅰ , Ⅲ ), 该站位位于 37° 40.5′ N、 118° 28.7′ E, 山东省境内现代黄河三角洲之上 , 1855年海岸线和第二道贝壳堤 (原文中称作贝壳堤 H2)东北 , 孔口高程 + 5.5 m. H9602站位只有一个钻孔Ⅱ , 位于山东省境内 37° 4.8′ N、 118° 54.3′ E,1855年海岸线和第二道贝壳堤之西南 , 第三道贝壳堤 (原文中称作贝壳堤 H1)之东北 , H9601站位之西偏南 , 孔口高程 + 4.8 m. 两个站位共测得 30个 14C年龄数据 . 相似文献
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海产经济贝类壳色多态性的研究进展 总被引：5，自引：0，他引：5
海产贝类的贝壳颜色是一个对生产、育种有重要意义的可遗传性状.滨螺、海湾扇贝、皱纹盘鲍、牡蛎、蛤类及珍珠贝等贝类的壳色多态性的遗传研究及壳色选择育种的角度综述了目前海产贝类壳色性状遗传机制的研究进展及壳色多态性在育种中的应用,为进一步开展壳色遗传机制和选择育种研究提供理论基础. 相似文献
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Wang Deyu Chen Tieyun
Associate Professor Dept. of Naval Architecture Ocean Engineering Shanghai Jiaotong University Shanghai
Professor Dept. of Naval Architecture Ocean Engineering Shanghai Jiaotong University Shanghai 《中国海洋工程》1995,(1)
- The Bodner-Partom constitutive equation is used to study the viscoplastic torsional bucklingof perfect cylindrical shell. By treating the viscoplastic shell as an orthotropic shell at each moment and neglecting the inertia term, the critical torque is determined from a set of homogeneous linear equations. The strain rate sensitivity is mainly discussed in the present paper. 相似文献
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The dynamic torsional buckling and post-buckling of elasto-plastic circular cylindrical shell isstudied.By the usage of the Bodner-Partom constitutive relation,the present visco-plastic problem is treat-ed as an orthotropic elastic problem.Based on the nonlinear large deflection shell therory,the governingdynamic buckling equation is solved by the Runge-Kutta method,and the critical buckling stress is deter-mined by the B-R criterion.The present paper is mainly focused on the imperfection sensitivity,the strainrate sensitivity,and the dynamic post-buckling characters for the shell loaded dynamically with a constantshear strain rate.Numerical results show that the critical shear stress and imperfection sensitivity will in-crease with the increase of strain rate.It is found that the elastic buckling stress is more sensitive toimperfection than the visco-plastic buckling.The present research also reveals some dynamic post-bucklingcharacters for the cylindrical shell,and it is shown that the shell will vibra 相似文献
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对复杂壳体结构件进行批产前的首件应力检测、状态评估，尽早摸清壳体水压试验中关键部位的应力应变情况，对试验数据进行相关处理后，得到该产品相应工作状态下的关键部位应力值，进而达到对结构件的强度分析和设计仿真数据积累的目的。根据设计要求对壳体 15 个位置进行应力应变测试，通过计算找到应力值最大的位置点。通过本次测试研究发现，测试结果均小于相应材料的屈服强度，壳体结构设计满足水下耐压条件。 相似文献
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旨在研究声固耦合法模拟水下爆炸对圆筒的冲击,运用大型有限元软件 ABAQUS 声固耦合算法分别对密封圆筒与透水圆筒水下爆炸模型进行计算分析,并与理论公式结果进行对比分析。结果表明：利用 ABAQUS 声固耦合算法可以比较准确地模拟圆筒水下爆炸分析,能够满足工程要求;另外,在相同的水下爆炸作用下,透水圆筒比密封圆筒具有更好的抗爆炸和抗冲击性能。 相似文献
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《Journal of Sea Research》2000,43(1):53-64
Common whelks Buccinum undatum collected from the southern North Sea were investigated to study the amount of shell damage and mortality caused by beam trawl fishery. The ability of whelks to repair their damaged shells was studied in the laboratory. Whelks (n=876) were caught with a fine-meshed 3-m beam trawl or with commercial 4- and 12-m beam trawls, while in some areas whelks were also caught with baited traps (used as a reference). Shell damage varied considerably for the different groups. In whelks collected by beam trawling, minor shell damage was observed in 17–75%, and severe damage (when protection against predators and scavengers is lost) in 10–83%. Whelks caught with baited traps sustained only minor shell damage (0–27% of the individuals). Their damage was statistically significantly less than in beam-trawled specimens. Most whelks in all groups exhibited signs of former shell damage, which had since been repaired. Whelk survival was studied in the laboratory over a six-week period. Only 40% of the whelks caught with the 12-m beam trawl survived, irrespective of the damage suffered. Whelks that survived and recovered had repaired their shell after six weeks. More than 95% of the whelks caught with baited traps survived the six-week experimental period; this is statistically significantly higher than the survival of animals caught with the 12-m beam trawl. At five locations females were screened for the presence and stage of imposex. Mild imposex development (mostly stages 1 and 2) was observed at all locations with incidences of 32–80%. It is concluded that beam trawl fishery may be a much greater source of mortality in common whelks than previously thought. 相似文献
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Christopher M. Prince Richard D. Elmore Robert Ehrlich Orrin H. Pilkey 《Geo-Marine Letters》1987,7(2):103-112
The Black Shell Turbidite on the Hatteras Abyssal Plain covers at least 50,000 km2, with a volume over 100 km3. It was initiated by failure on the upper continental slope and was channeled southeast through Hatteras Canyon to the plain. Provenance related shape studies indicate that on the plain the current separated into a sandy Phase which flowed S-SE and a lutitic phase, which traveled E-SE and then veered to the south. A change in the direction of slope caused the sandy phase to be deflected to the SE, where it merged with the lutitic phase on the eastern margin of the plain. 相似文献