共查询到15条相似文献，搜索用时 203 毫秒
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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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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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超高分子量聚乙烯和高密度聚乙烯网线的拉伸力学性能比较研究 总被引：11，自引：0，他引：11
在标准实验室环境里，对超高分子量聚乙烯(UHMWPE)和高密度聚乙烯(HDPE)网线的拉伸力学性能进行了比较研究。结果表明：UHMWPE网线较HDPE网线具有较高的强度、拉伸模量和结强损失率；而HDPE网线较UHMWPE网线具有较高的断裂伸长率。结论可供渔具设计及网线材料选配时参考。 相似文献
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深水系泊高强聚乙烯缆绳的蠕变及破断实验研究 总被引：1，自引：0，他引：1
相对于同一破断强度的聚酯(polyester)缆绳,高强聚乙烯(HMPE)缆绳具有更高的刚度、更小的自重和直径、更易运输和安装的优点,因此高强聚乙烯缆绳被引入到系泊系统以替代聚酯缆绳。然而高强聚乙烯缆绳又存在易发生蠕变甚至蠕变破断的不利因素,研究其蠕变和蠕变破断的力学特性就显得尤为迫切。首先设计了合成纤维缆绳实验系统,对HMPE子股缆绳开展了系统的蠕变和蠕变破断实验。基于实验数据,分析了HMPE子缆的蠕变和蠕变破断特性;通过调研HMPE试样的蠕变实验数据,提出了HMPE考虑温度和载荷影响的HMPE纱线蠕变率经验公式,采用该经验公式并结合已有的缆绳比尺换算关系,可以推算出HMPE缆绳的蠕变率;此外,基于所获得的蠕变破断实验数据,提出了HMPE缆绳在定常载荷下的蠕变寿命经验公式。这些成果对HMPE缆绳应用于深水绷紧式系泊系统具有重要意义。 相似文献
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聚乙烯吡咯烷酮碘对中国对虾的毒性试验 总被引：3，自引：1，他引：2
目前,对虾养殖生产中已使用PVP-I(聚乙烯吡咯烷酮碘)防治对虾病毒病,但仍借鉴防治鱼类病害的使用方法,各种产品的有效碘含量也不尽相同,使用时不易掌握。作者就该药在对虾养殖中的使用进行了较为系统的研究。本文将毒性试验结果报告如下。1 材料和方法1.1 材料聚乙烯吡咯烷酮碘为市售商品,有效碘含量18%～21.5%。对虾各期幼体及幼虾取自生产现场。试验用水为砂滤海水,经脱脂棉二次过滤后使用。1.2 方法1.2.1 急性毒性试验 试验在烧杯中进行,定量加入试验用水1000ml,水浴保持所需温度,分别加入PVP-I母液,使水中有效碘浓度达到设定浓… 相似文献
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众所周知,源于羧甲基甲壳素(carboxymethyl chitin, CMC)的吸附材料在重金属离子和染料的去除方面具备诸多优势,如高效吸附性、选择吸附性、环境友好、制备原料储量丰富等。为有效去除不同水介质(去离子水、模拟废水、自来水和海水)中的六价铬Cr(Ⅵ),将甲壳质(chitin, CT)羧甲基化获得CMC,后以聚乙烯亚胺(polyethyleneimine, PEI)为交联剂和功能基团,采用反相乳化法首次合成了一种新的PEI修饰的CMC复合微球(CMC-PEI),并对CMC-PEI微球的理化性质、吸附条件及吸附机理进行了研究。结果表明, PEI通过酰胺反应成功接枝到CMC上形成CMC-PEI微球。CMC-PEI微球对Cr(Ⅵ)的吸附行为符合伪二级动力学模型,说明在吸附Cr(Ⅵ)的过程中,化学吸附起主导作用。根据Liu模型计算得知, CMC-PEI微球对Cr(Ⅵ)的最大理论吸附量为244.01 mg/g。吸附-解吸附实验发现, NaOH能有效地从微球表面解吸Cr(Ⅵ),表明吸附后的微球具有良好的循环再生性能。光谱学分析结果表明, CMC-PEI微球对Cr(Ⅵ)的去除主要包括静电... 相似文献
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微塑料因粒径小、比表面积大，可作为重金属、有机污染物以及病原微生物的载体。已有研究表明，微塑料表面附着的微生物主要以生物膜的形式存在。本研究以山东省海岸带环境中常见的两类软质塑料——发泡类聚苯乙烯（expanded polystyrene，EPS）和聚乙烯薄膜（polyethylene films，PE）为研究对象，比较了MP FastDNA®和MOBIO PowerSoil®两种DNA提取试剂盒对微塑料表面生物膜DNA的提取效果，探讨了不同的微塑料粒径和数量对DNA提取效果的影响。结果表明，MP FastDNA®试剂盒对两种软质微塑料表面生物膜DNA的提取浓度显著低于MOBIO PowerSoil®试剂盒（1.0~12.5倍）。采用MP FastDNA®试剂盒提取的PE表面DNA的浓度约为EPS的1.3~4.4倍。当微塑料数量不大于20片时，小粒径（1~3 mm）的EPS表面生物膜DNA浓度显著高于大粒径（3~5 mm） EPS，而对于PE薄膜则相反。对于两种粒径的EPS，微塑料表面DNA浓度均随着微塑料数量的增加而显著增加，但对于小粒径（1~3 mm）的PE薄膜，DNA浓度随微塑料数量的增加呈先增后减的趋势；而大粒径（3~5 mm）的PE薄膜表面DNA浓度随微塑料数量的增加而降低。微塑料的粒径和数量对其表面DNA提取效果影响的差异与微塑料的类型及其理化性质有关。本研究可为海洋与海岸环境中微塑料表面微生物群落组成与多样性研究提供方法支撑。 相似文献
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The evolution and breaking of a propagating internal wave are directly numerically simulated using a pseudo-spectral method. The mechanism of PSI （ parametric subharmonic instability） involved in the evolution is testified clearly. It dominates gradually in nonlinear resonant interactions. As a consequence, the energy cascades to a second plant wave packet which has lower frequencies and higher wavenumbers than that of the primary wave. With the growth of this wave packet, wave breaking occurs and causes strongly nonlinear regime, i.e. stratified turbulence. The strong mixing and intermittent of the turbulence can be learned from the evolution of the total energy and kurtosis of vorticity vs. time. Some statistic properties of the stratified turbulence are also analyzed, including the spectra of KE （kinetic energy） and PE （potential energy）. The results show that the PE spectra display a wavenumber range scaling as 0. 2 N^4ky^-3 （N is the Brunt - Vaisala frequency, k, is the vertical wavenumber）, which is called buoyancy sub-range. However, the KE spectra cannot satisfy the negative cubic law of vertical wavenumber, which have a much larger downtrend than that of the PE spectra, for the potential energy is transferred more efficiently toward small scales than the kinetic energy. The Cox number of diapycnal diffusivity is also calculated, and it shows a good consistency with the observations and deductions in the ocean interior, during the stage of the stratified turbulence maintaining a fairly active level. 相似文献
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A numerical wave tank is used to investigate the onset and strength of unforced wave breaking, and the waves have three types of initial spectra： constant amplitude spectrum, constant steepness spectrum and Pierson-Moscowitz spectrum. Numerical tests are performed to validate the model results. Then, the onset of wave breaking is discussed with geometric, kinematic, and dynamic breaking criteria. The strength of wave breaking, which is always characterized by the fractional energy loss and breaking strength coefficient, is studied for different spectra. The results show how the energy growth rate is better than the initial wave steepness on estimating the fractional energy losses as well as breaking strength coefficient. 相似文献
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A numerical wave tank is used to investigate the onset and strength of unforced wave breaking, and the waves have three types of initial spectra: constant amplitude spectrum, constant steepness spectrum and Pierson-Moscowitz spectrum. Numerical tests are performed to validate the model results. Then, the onset of wave breaking is discussed with geometric, kinematic, and dynamic breaking criteria. The strength of wave breaking, which is always characterized by the fractional energy loss and breaking strength coefficient, is studied for different spectra. The results show how the energy growth rate is better than the initial wave steepness on estimating the fractional energy losses as well as breaking strength coefficient. 相似文献
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The presence of pollutants on plastic debris is an emerging environmental hot topic. Understanding the surface alteration of plastics while in the marine environment increases our understanding of the pollutant–plastic debris interaction. Plastic pellets are widely distributed throughout the world oceans. Eroded and virgin polyethylene (PE) and polypropylene (PP) pellets were studied for their surface properties to better understand the interaction between plastic and compounds in marine environment. Surface properties such as point of zero charge, surface area and pore volume, surface topography, functional groups and acid–base behavior are important factors which affect sorption. Virgin plastic pellets had homogeneous smooth surfaces that do not have any acid–base behavior. Eroded PE demonstrates an altered surface that at seawater pH acquires a negative charge due to ketone groups. The uneven surface and possible functional groups could have been formed from the erosion processes while floating at the sea surface and might explain the interaction of eroded plastics with microbes and metals. 相似文献