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181.
波浪的方向分布对波浪的传播及其与工程结构物的作用都具有明显影响,目前现有的研究大多是基于单向波浪进行的。为了研究方向分布对群墩结构上的爬高影响,基于规则波浪与群墩作用的理论解,结合多向不规则波浪的造波方法,建立了多向不规则波浪与群墩作用的计算模型,同时进行了物理模型试验对模型的有效性进行了验证。系统地对群墩周围及表面上的波浪爬高进行了计算分析,结果表明,方向分布对波浪爬高具有较大的影响,且不同位置处的影响并不相同,在实际的工程设计中如果按照单向波浪计算,可能低估或者高估群墩周围的爬高。 相似文献
182.
传统的渔业资源评估均假设鱼类的生长参数是匀质的,然而近年来越来越多的研究表明海洋鱼类生长存在空间异质性。为探究海州湾鱼类生长参数的空间异质性现象,本研究分析了2013–2018年海州湾及其邻近海域方氏云鳚(Pholis fangi)、尖海龙(Syngnatus acus)、小黄鱼(Larimichthys polyactis)和赤鼻棱鳀(Thryssa kammalensis)的空间分布,使用电子体长频率分析方法结合Bootstrap重抽样方法估算了这4种鱼类的生长参数及其在深、浅水区域中的差异。结果显示,这4种鱼类生长参数均表现出一定的空间异质性,其中尖海龙和小黄鱼生长参数的空间异质性表现较为明显。这种差异可能是由于空间上的理化条件、群落结构以及物种本身洄游分布的差异而产生的。 相似文献
183.
Li Xingxing Ma Tengzhou Xie Weiliang Zhang Keke Huang Jiaxin Ren Xiaodong 《GPS Solutions》2019,23(2):1-16
GPS Solutions - As parameter estimation and statistical testing are often intimately linked in the processing of observational data, the uncertainties involved in both estimation and testing need... 相似文献
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The source rock from which the sillimanite gneisses derive mainly was the biotite plagioclase gneiss in the Larsemann Hills. It is the deformation-metamorphism process under special pressure and temperature condition, not the original rock compositions, that controls the presence of sillimanite. To a great degree, the sillimanite gneiss was the mixture of the detaining materials of the migrating felsic melt from the bt-plagioclase gneiss that underwent partial melting and the relics when the melt was removed. In sillimanitization the original rock had been changed substantially in chemical composition. The related metamorphism process severely deviated from the isochemical series, the process was of, therefore, an open system. In addition, the Al2O3 contents of the original rock was an important, but not critical factor for the formation of sillimanite, i.e., the sillimanite-bearing rock need not be of aluminum rich in composition, and vise contrarily, the aluminum rock may not produce sillimanite. The authors of the present paper postulate that the source rock from which the aluminum rich rock derives need not be of aluminum rich, but sillimanitization is generally the Al2O3 increasing process. The aluminum rich sediments such as clay or shale need not correspond directly to sillimanite-rich gneisses. No argillaceous rock present equals to sillimanite-rich gneiss in chemical composition. The protoliths to the sillimanite gneisses from the Larsemann Hills, east Antarctica, and their adjacent area may be pelite, shale greywacke, sub-greywacke, quartz sandstone and quartz-tourmalinite. If correct, the conclusion will be of significant implication for the determination of the sillimanite gneiss formation process and the reconstruction of the protolith setting. 相似文献
186.
Guoyan Ren Bafang Li Xue Zhao Yongliang Zhuang Mingyan Yan Hu Hou Xiukun Zhang Li Chen 《中国海洋大学学报(英文版)》2009,8(1):83-88
In order to select an optimum extraction method for the target glycoprotein (TGP) from jellyfish (Rhopilema esculentum) oral-arms, a high performance liquid chromatography (HPLC)-assay for the determination of the TGP was developed. Purified
target glycoprotein was taken as a standard glycoprotein. The results showed that the calibration curves for peak area plotted
against concentration for TGP were linear (r = 0.9984, y = 4.5895x+47.601) over concentrations ranging from 50 to 400 mgL-1. The mean extraction recovery was 97.84% (CV2.60%). The fractions
containing TGP were isolated from jellyfish (R. esculentum) oral-arms by four extraction methods: 1) water extraction (WE), 2) phosphate buffer solution (PBS) extraction (PE), 3) ultrasound-assisted
water extraction (UA-WE), 4) ultrasound-assisted PBS extraction (UA-PE). The lyophilized extract was dissolved in Milli-Q
water and analyzed directly on a short TSK-GEL G4000PWXL (7.8 mm×300 mm) column. Our results indicated that the UA-PE method
was the optimum extraction method selected by HPLC. 相似文献
187.
Mountain areas are often rich in ecological diversity and recreational opportunities. Mountain tourism is thought to be an effective and important means for maintaining and expanding rural economies and, thus, improving the living conditions of rural societies. As mountain tourism service research is a professional field with several disciplines involved, a multi-disciplinary management pIatform is needed and it facilitates participation in sustainable mountain development by diverse stakeholders. With the source regions of the Yangtze and the Yellow River as a case study, this paper presents a conceptual framework for an adaptation management of mountain tourism services according to technical, policy, social and economic dimensions. The framework is based on a vulnerability assessment of mountain ecosystems, and can serve as a reference for the development of tourism service in other mountain areas. 相似文献
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The dynamic energy budget (DEB) theory assumes that the feeding of an organism in relation to food density follows the type-II functional response when food consists of purely digestible organic matter. However when faced with a food source high in inorganic content, an organism needs to adapt physiologically to maximise organic extraction. Indeed filter-feeding marine bivalves inhabiting turbid coastal waters cope with large fluctuations in food quality by selectively ingesting and pseudofaeces production. Data from feeding experiments with the New Zealand greenshell mussel Perna canaliculus have demonstrated that inorganic particles contribute some uncertainty to the estimate of the half-saturation coefficient. Incorporating inorganic matter into the functional response would improve the prediction of energy uptake. 相似文献
190.
在三元复合驱矿场应用实践中,由于三元复合体系自身流度控制能力的局限性,必须通过聚合物凝胶前置段塞来改善吸液剖面,这就涉及到聚合物凝胶与三元复合体系的配伍性。通过向三元复合体系中加入有机铬,考察Cr^3+对三元复合体系黏度、界面张力和阻力系数等性能影响,进而对Cr^3+聚合物凝胶与三元复合体系配伍性以及Cr^3+在改善三元复合体系性能方面的作用做出评价。结果表明,Cr^3+的加入对三元复合体系黏度和界面张力影响不大,但阻力系数和残余阻力系数却明显增加。当采用Cr^3+聚合物凝胶作为前置段塞或采用添加Cr^3+的三元复合体系进行复合驱油实验时,其采收率增加幅度都要高于普通三元复合驱。这不仅显示出Cr^3+聚合物凝胶与三元复合体系间良好的配伍性,而且为改善三元复合驱增油效果提供了新的途径。 相似文献