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Developing the s Factor
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作者 M. Pawtowski 《Journal of Shipping and Ocean Engineering》 2011年第1期1-7,共7页
The current various proposals at the International Maritime Organisation (IMO) for the s factor (probability of surviving a given flooding) make no reference to survival time. The paper shows a direct link of the ... The current various proposals at the International Maritime Organisation (IMO) for the s factor (probability of surviving a given flooding) make no reference to survival time. The paper shows a direct link of the "prime" s factor with the time to capsize and shows how to utilise experimental data from 30-minute test runs for the s factor based on longer duration of tests. Unexpectedly, the extension of tests has a modest effect on the survival factor, and hence-modest effect on subdivision index A. Much more important is improving a deficient formulation for the required index R, as flooding cases with si = 1 have an infinite survival time. 展开更多
关键词 Factor s survival time rulemaking.
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An integrated biomarker response index for the mussel Mytilus edulis based on laboratory exposure to anthracene and field transplantation experiments 被引量:1
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作者 袁梦琪 王悠 +3 位作者 周斌 菅潇扬 董文隆 唐学玺 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第5期1165-1178,共14页
Organic pollution is a serious environmental problem in coastal areas and it is important to establish quantitative methods for monitoring this pollution. This study screened a series of sensitive biomarkers to constr... Organic pollution is a serious environmental problem in coastal areas and it is important to establish quantitative methods for monitoring this pollution. This study screened a series of sensitive biomarkers to construct an integrated biomarker response (IBR) index using Mytilus edulis. Mussels were exposed to the polycyclic aromatic hydrocarbon anthracene trader controlled laboratory conditions and the activities of components of the glutathione antioxidant system, and the concentrations of oxidative-damage markers, were measured in the gills and digestive glands. Anthracene exposure resulted in increased levels of malondialdehyde (MDA) and superoxide radicals (O2-·), indicating that oxidative damage had occurred. Correspondingly, anthracene exposure induced increased activities of glutathione S-transferase (GST), glutathione peroxidase (GPx) and reduced glutathione (GSH) in digestive glands, and GPx and glutathione reductase (GR) in gills, consistent with stimulation of the antioxidant system. A field experiment was set up, in which mussels from a relatively clean area were transplanted to a contaminated site. One month later, the activities of GST, GPx and GR had increased in several tissues, particularly in the digestive glands. Based on the laboratory experiment, an IBR, which showed a positive relationship with anthracene exposure, was constructed. The IBR is suggested to be a potentially useful tool for assessing anthracene pollution. 展开更多
关键词 nthracene Mytilus edulis BIOMARKER integrated biomarker response transplant experiment
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北运河水系底栖动物群落结构与水环境质量评价 被引量:26
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作者 顾晓昀 徐宗学 +4 位作者 王汨 殷旭旺 刘麟菲 张欣 左德鹏 《湖泊科学》 EI CAS CSCD 北大核心 2017年第6期1444-1454,共11页
为全面了解北运河水系的底栖动物群落结构和水环境质量,于2015年5月对北运河水系33个样点的底栖动物和水体理化性质进行了调查,分别采用综合水质标识指数法和底栖动物BI指数法对北运河水系进行水质评价,并通过Kolmogorov-Smirnov检验判... 为全面了解北运河水系的底栖动物群落结构和水环境质量,于2015年5月对北运河水系33个样点的底栖动物和水体理化性质进行了调查,分别采用综合水质标识指数法和底栖动物BI指数法对北运河水系进行水质评价,并通过Kolmogorov-Smirnov检验判断正态性,用Pearson相关分析方法对两种评价结果进行比较和分析.结果表明:北运河水系共采集到底栖动物23种,隶属于3门4纲6目11科11属,以水生昆虫和软体动物为主,整个水系底栖动物群落结构单一;底栖动物BI指数法的评价结果显示,72%的采样点水质为中污染(Ⅳ)或重污染(Ⅴ);综合水质标识指数法的评价结果显示,超过57%的采样点水质为Ⅳ类及以下;根据K-S检验,两组评价得分均符合正态分布;Pearson相关分析显示两种评价结果呈显著正相关.两种评价结果总体上呈现出相同的趋势,均显示北运河水系整体水质状况较差,干流水质状况优于支流,上游水质状况优于下游,温榆河上游、坝河下游、通惠河上游和凉水河的水质状况较差,温榆河源头和坝河上游的水质状况较好.两种评价结果在个别点位存在一定差异,具体表现为基于水体理化因子的评价结果稍优于水质生物评价结果,造成这种差异的原因是两种评价方法在时空尺度上存在差异.针对城市化水平较高、人类活动干扰较强的北运河水系,同时采用这两种评价方法有助于全面了解其复杂的水环境质量. 展开更多
关键词 底栖动物 群落结构 s/指数 综合水质标识指数 水环境质量评价 北运河
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On Twisted Atiyah-Singer Operators(Ⅰ)
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作者 周建伟 《Journal of Mathematical Research and Exposition》 CSCD 1999年第1期44-48,共5页
In this paper we show that the de Rham and the Signature operators on a Riemannian manifold are all isomorphic to some twisted Atiyah-Singer operators. Then the local index theorem and local Lefschetz fixed point form... In this paper we show that the de Rham and the Signature operators on a Riemannian manifold are all isomorphic to some twisted Atiyah-Singer operators. Then the local index theorem and local Lefschetz fixed point formulas of these operators can be obtained from the corresponding theorems of twisted Atiyah-Singer operators. 展开更多
关键词 Clifford module spin group elliptic operator twisted Atiyah-singer operator index theorem
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Resonance and rapid decay of exponential sums of Fourier coefficients of a Maass form for GL_m(Z) 被引量:2
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作者 REN XiuMin YE YangBo 《Science China Mathematics》 SCIE CSCD 2015年第10期2105-2124,共20页
Let f be a full-level cusp form for GLm(Z) with Fourier coefficients Af(n1,..., nm-1). In this paper,an asymptotic expansion of Voronoi's summation formula for Af(n1,..., nm-1) is established. As applications of t... Let f be a full-level cusp form for GLm(Z) with Fourier coefficients Af(n1,..., nm-1). In this paper,an asymptotic expansion of Voronoi's summation formula for Af(n1,..., nm-1) is established. As applications of this formula, a smoothly weighted average of Af(n, 1,..., 1) against e(α|n|β) is proved to be rapidly decayed when 0 < β < 1/m. When β = 1/m and α equals or approaches ±mq1/mfor a positive integer q, this smooth average has a main term of the size of |Af(1,..., 1, q) + Af(1,..., 1,-q)|X1/(2m)+1/2, which is a manifestation of resonance of oscillation exhibited by the Fourier coefficients Af(n, 1,..., 1). Similar estimate is also proved for a sharp-cut sum. 展开更多
关键词 cusp form for GLm(Z) Voronoi’s summation formula Fourier coefficient of cusp forms REsONANCE
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