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渔用高强度聚乙烯和普通聚乙烯单丝结构与性能的比较研究 总被引:9,自引:1,他引:9
为给渔具设计与材料的合理选配提供科学依据,通过差示扫描量热法(DSC)、广角X射线衍射(WAXD)及扫描电镜(SEM)等方法的比较,研究了渔用高强度聚乙烯(high-strength polyethylene,简称HSPE)和普通聚乙烯(PE)单丝的结构与性能。结果表明,HSPE单丝的断裂强度和结节强度比普通PE单丝分别提高了14.54%,3.05%,而断裂伸长率降低了44.44%;HSPE单丝的结晶度和声速值比普通PE单丝分别增加了6.20%和76.8%;HSPE单丝微晶尺寸稍大于普通PE单丝,而晶胞参数变化很小;HSPE单丝内部结晶形态为平行的串晶和纤维复合结构。正是由于结晶度、取向度的提高以及单丝内部生成了平行的串晶和纤维复合结构,导致了渔用HSPE单丝强度的提高。 相似文献
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高强度聚乙烯菱形网目经编网片的力学性能初步研究 总被引:7,自引:0,他引:7
给网箱设计与渔用材料的合理选配提供参考,初步研究了渔用高强度聚乙烯菱形网目经编网片(简称HSPE经编网片)的力学性能。研究结果表明,(1)在同等条件下,36股HSPE经编网片网目强力、网片纵向断裂强力分别比36股普通聚乙烯菱形网目经编网片(简称PE经编网片)增加了48.9%,11.6%,而前者的网片纵向断裂伸长率比后者减少了29.4%;(2)在相同网目长度条件下,36股HSPE经编网片网目强力、网片纵向断裂强力分别比42股锦纶菱形网目经编网片(简称PA经编网片)增加了27.2%,37.9%,而前者的网片纵向断裂伸长率比后者减少了33.6%;(3)36股HSPE经编网片较36股PE经编网片和42股PA经编网片具有性能价格比优势;HSPE经编网片在网箱养殖等渔业生产中推广应用上具有可行性。 相似文献
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渔用高强度聚乙烯和普通聚乙烯绞捻网片的拉伸力学性能比较研究 总被引:6,自引:0,他引:6
为给深水网箱设计与渔用材料的合理选配提供依据,应用ISO1806等对渔用高强度聚乙烯绞捻网片(以下简称HSPE绞捻网片)和普通聚乙烯绞捻网片(以下简称PE绞捻网片)的拉伸力学性能进行了比较研究。结果表明,(1)在同等条件下,36股HSPE绞捻网片的网目连接点断裂强力和网片单线断裂强力分别比52股PE绞捻网片增加了3.1%,3.7%;而前者的目脚直径和网片阻力可较后者减少19.6%。(2)对网片强力进行了再现性研究,36股HSPE和52股PE绞捻网片网目连接点断裂强力的标准偏差分别为35.93N,25.61N,再现性标准偏差分别为31.07N,36.93N;网片单线断裂强力的标准偏差分别为19.91N,13.49N,再现性标准偏差分别为20.48N,15.49N;网片强力测试数据的变异系数均小于4%;表示测试结果的分散性较小。(3)36股HSPE绞捻网片成本可较52股PE绞捻网片减少38.9%,其在渔业生产中进行推广应用具有可行性。(4)GB/T4925作为一个标准,对绞捻网片来说,存在不足,建议对GB/T4925进行修订。 相似文献
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福建渔用饲料业现状与发展趋势 总被引:2,自引:0,他引:2
当前福建省渔用饲料工业正处在发展中的稳定调整阶段,饲料生产能力、产品产量和市场需求应将基本保持稳定,安全卫生符合生态要求已成为衡量行业健康发展的重要指标,应成为企业追求发展的方向和政府监管的重点. 相似文献
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近几年我国渔用药物的应用越来越广泛,渔用药物的研制和生产规模取得较大发展。本文对渔用药物的定义,主要研究内容进行了描述,对目前应用范围较广的药物进行了简单分类,并对渔用药物的现状进行了分析,提出了在研制,生产,销售和使用等方面存在的一些主要问题,最后对我国渔用药物发展战略提出了几点建议。 相似文献
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渔用抗菌药物代谢动力学和残留的研究现状 总被引:7,自引:0,他引:7
随着生活水平的不断提高,人们对水生动物食品的需求量亦不断增加。我国有水产养殖的天然优势,海岸线长、江河湖泊资源丰富,适合水产养殖业的发展。八十年代以来,我国水产养殖规模飞速扩大,集约化程度不断提高,到1999年养殖产量已占渔业总产量的58%多年居世界首位。但是在养殖产量提高的同时,由于养殖规模扩大、自身有机污染积累、养殖生态环境恶化及区域间苗种的频繁交流等因素影响,致使各种疾病的发生率越来越高,给养殖业造成严重损失[1]。据初步统计:1999年全国水产养殖生产中因病害给渔业造成的损失超过170亿元,其中海水养殖… 相似文献
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本文对我国目前使用广泛的捕捞船型8101、8154所配备的渔用电子仪器设备在鱿钓作业中的使用与维修问题进行探讨。 相似文献
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利用数据挖掘方法对1990年1月—2001年7月10余年的WCPO金枪鱼围网作业生产数据以及该时段的18个与WCPO金枪鱼围网产量相关的海洋环境因子进行分析,将信息增益分析技术和基于粗糙集的属性化简方法相结合用以确定影响WCPO金枪鱼围网产量的关键因子集。利用多元回归分析方法建立基于关键因子集的预测模型,经过大量试验对比选择较佳的预测模型,达到了理想的效果。同时,验证了所确定关键因子集的可靠性,有效性。首次利用多种数据挖掘方法相结合的方式对多种影响因子进行分析,开展渔情预报研究,达到了较好的效果,为渔情预报研究提供了一种新思路,同时为渔业生产提供了可靠的依据。 相似文献
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诱鱼灯光场计算及其对光诱鱿鱼浮拖网作业的影响 总被引:9,自引:0,他引:9
本文运用诱鱼灯光照度的有关公式,计算了光诱鱿鱼浮拖网作业中的光场分布及变化,结合鱿鱼趋光行为习性,分析现有渔具渔法的适应性。结果表明;使用16盏铊铟灯水上灯,诱鱼最大水平距离比仅使用水下灯增加约680倍,但水上灯从16盏增加到40盏地,从经济角度分析不很理想;在集鱼过程中,关闭最后一组水上灯后,应有白炽灯经过降压后再地渡到水下灯集鱼;导鱼灯在向网口移动的过程中应继续降低低电压; 相似文献
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The East Sea, with an average depth of 1700 m, has long been subject to heavy fishing pressure, resulting in derelict fishing gear. Most derelict fishing gears, such as fishing nets, fishing ropes, and crab pots, sink to the seabed and do not degrade. This gear results in “ghost fishing,” which has adverse impacts on deep benthic habitats. Recently, the Korean government has started to remove derelict fishing gears from the deep seabed of the East Sea by bottom trawling with heavy hooks (50–80 kg) and ropes. A total of 207.8 and 252.2 tons of marine debris in 2009 and 2010, respectively, were removed from the seabed, most of which were derelict fishing gears. Contrary to monitoring surveys and clean-up in shallow waters, removal of marine debris from remote deep habitats is much more difficult and dangerous for removal crews. 相似文献
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黄渤海区捕捞结构的研究 总被引:4,自引:0,他引:4
根据2010年对黄渤海沿海32个主要渔港、渔村和5家网具生产厂家的实地调查和现场测量资料,结合2009年度三省一市(河北、辽宁、山东、天津)的渔具渔法调查报告以及1983~2009年中国渔业年鉴中记载的捕捞产量分类统计资料,对黄渤海区捕捞结构进行了研究.研究结果表明,黄渤海区主要捕捞品种有30种之多,其中年渔获量超过万吨的有14种鱼类、5种甲壳类、4种头足类、2种海蜇和6种贝类.渔业资源品种的多样性决定了黄渤海区捕捞结构的多样化和多层次的特点,现有9大类19型23式130种网型或作业方式,同时受渔业资源变动的影响,捕捞网具也在变化,不断有旧的渔具消失和新的网具出现.其中,拖网是主要作业方式,贡献率为38.47%~51.79%,且近几年还有上升的趋势;其次为刺网,贡献率从1983年最低时的7.66%逐步上升到目前的30.14%;第三为张网,贡献率从1985年最高时的34.31%下降到目前的10.49%;围网和钓具的贡献率一直较低,均不足4%,其他渔具的贡献率为5.98%~13.30%.目前黄渤海区渔业结构的调整方向应当是减少拖网作业,控制刺网总量,限制张网、陷阱类渔具和地笼,鼓励发展钓渔业 相似文献
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Information coming from fishery monitoring, surveys and experimental fishing with participation of fishers was employed to determine the impact of an artisanal gear, ‘boliche’, on the biodiversity of the Ciénaga Grande de Santa Marta (CGSM), an estuarine lagoon on the Caribbean coast of Colombia. Fishery monitoring (catch data) included landings before (1968 and 1978) and after (1994–1996) the introduction of the boliche in the CGSM (1985), whereas surveys were conducted seasonally during 1993–1994. Fishing experiments involved evaluating different mesh sizes and the short-term effect of physical disturbance by the boliche. Monitoring suggested potential trophic effects of this fishing gear: the catch of large, long-lived, carnivorous species declined after the introduction of the boliche in the CGSM, whereas catch rates of smaller, shorter-lived, and lower trophic level species increased. Surveys revealed that the boliche retained 41 species. The by-catch made up 62% of the total catch and the remaining 38% involved the three target species Eugerres plumieri, Mugil incilis and Cathorops spixii. Selectivity experiments showed that 2.5 in. stretched mesh size gill nets caught more species than the 3.0-in. mesh. The smaller mesh also increased the risk of a critical reduction in the spawning stock of target species (notably E. plumieri); a situation that could affect the fish community if mesh sizes lower than 2.5 in. were intensively used. Suspended particulate matter significantly increased after fishing activity, with higher resuspension on mud-shells and mud substrata, whereas dissolved oxygen showed no appreciable changes after fishing operations. Notwithstanding, the activity of the boliche would generate sediment resuspension between 382 and 470 t day−1, which could lead to potential cascade impacts on water quality. We propose a framework of redundancy in management measures in order to simultaneously reach management and conservation goals. 相似文献
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Despite its legal prohibition since 1998, the nylon monofilament net is still widely used in Senegalese artisanal fisheries. To achieve a complete ban on monofilament use, it is necessary to understand the main arguments for its continued use and what alternatives exist. Using a field experiment among local fishers as well as empirical knowledge and a literature review, this article highlights the challenges to the eradication of nylon monofilament. Our study shows that in a context where decision-makers pay too much attention to social, economic and political stakes, the efficiency of nylon monofilament nets confers a major advantage upon which fishers rely, and this counters any regulatory action against this type of gear. Moreover, numerous studies globally have indicated that communication campaigns that focus on the ghost-fishing power of this type of net seem to be inappropriate. We concluded that the issue of continued use of monofilament should be addressed through an integrated fisheries management programme that reduces overcapacity and fosters sustainable fishing practices. 相似文献
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Robert Kilpatrick Graeme EwingTim Lamb Dirk WelsfordAndrew Constable 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(4):486-491
Studies of the interactions of demersal fishing gear with the benthic environment are needed in order to manage conservation of benthic habitats. There has been limited direct assessment of these interactions through deployment of cameras on commercial fishing gear especially on demersal longlines. A compact, autonomous deep-sea video system was designed and constructed by the Australian Antarctic Division (AAD) for deployment on commercial fishing gear to observe interactions with benthos in the Southern Ocean finfish fisheries (targeting toothfish, Dissostichus spp). The Benthic Impacts Camera System (BICS) is capable of withstanding depths to 2500 m, has been successfully fitted to both longline and demersal trawl fishing gear, and is suitable for routine deployment by non-experts such as fisheries observers or crew. The system is entirely autonomous, robust, compact, easy to operate, and has minimal effect on the performance of the fishing gear it is attached to. To date, the system has successfully captured footage that demonstrates the interactions between demersal fishing gear and the benthos during routine commercial operations. It provides the first footage demonstrating the nature of the interaction between demersal longlines and benthic habitats in the Southern Ocean, as well as showing potential as a tool for rapidly assessing habitat types and presence of mobile biota such as krill (Euphausia superba). 相似文献