37 resultados para RI
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We measured the wear resistances of alumina, alumina/silicon carbide composite and alumina/mullite composite by abrasive wear. And we studied the influence of fracture mode and worn surface pullout on wear resistance. The results are as follows: the main wear mechanisms of alumina and alumina/silicon carbide were fracture wear and plastic wear respectively, and for alumina/mullite composite, fracture wear and plastic wear mechanisms worked together. The wear resistance of the alumina/silicon carbide composite and the alumina/mullite composite was better by a factor of 1 similar to 3 than that of the monolithic alumina. There were two main reasons for the better wear resistance, i.e., the improved mechanical properties and the more smooth worn surfaces. However, The primary reason was the reduction of area fraction of pullout on the worn surfaces induced by fracture mode transition. (C) 2007 Published by Elsevier B.V.
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Aluminium nitride (AlN) films grown with dimethylethylamine alane (DMEAA) are compared with the ones grown with trimethylaluminium (TMA). In the high-resolution x-ray diffraction Omega scans, the full width at half maximum (FWHM) of (0002) AlN films grown with DMEAA is about 0.70 deg, while the FWHM of (0002) AlN films grown with TMA is only 0.11 deg. The surface morphologies of the films are different, and the rms roughnesses of the surface are approximately identical. The rms roughness of AlN films grown with DMEAA is 47.4 nm, and grown with TMA is 69.4 nn. Although using DMEAA as the aluminium precursor cannot improve the AlN crystal quality, AlN growth can be reached at low temperature of 673 K. Thus, DMEAA is an alternative aluminium precursor to deposit AlN film at low growth temperatures.
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Hexangular indium nitride nanoflower pattern is observed from scanning electron microscopy and atomic force microscopy. The sample is grown on c-plane (0001) sapphire by metal organic chemical vapor deposition with intentional introduction of hydrogen gas. With the aid of hydrogen, a stable existence of metallic indium is achieved. This will induce the growth of InN nanoflowers via self-catalysis vapor-liquid-solid (VLS) process. It is found that the VLS process is modulated by the interface kinetics and thermodynamics among the sapphire substrate, indium, and InN, which leads to the special morphology of the authors' InN nanoflower pattern. (c) 2006 American Institute of Physics.
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目的研究TCS抗HIV-1的构效关系并对机制进行探讨。方法蛋白工程技术构建14个TCS突变 体,测定各种TCS突变体的细胞毒性和抗HIV恬性。结果活性中心突变体TCSM(120—123)与TcSEl60A/E189A在失 去绝大部分RI活性的同时,也几乎完全失去抗HIV活性。而另一个活性中心突变体TCSRl22G,RI活性下降160 倍,却仍保留一定的抗HIV活性。TCSC末端删除突变体(TCS(2,TCSo和TCScl。)抗HIV活性的下降(1.4—4.8 倍)与其RI活性呈平行下降(1.2—3.3倍);分别在C末端加上末端19个氨基酸延伸肽或KDEL信号肽的突变体 TCscl9。与TQkDEL,虽然保留全部的RI活性,但却几乎完全失去抗HIV活性;TCS抗原决定簇位点突变后对TCS 抗HIV.1括性没有显著影响,但当在抗原决定簇突变体所引入的Cys残基上加上PEG20K后,这些突变体则显著降 低了抗HIV-1的活性。TCS不能抑制HIV一1进入宿主细胞;对感染细胞和未感染细胞的融合没有抑制作用;TCS 也不能抑制HIV一1 rRT活性;TCS对病毒颗粒的直接杀伤作用不大。结论TCS抗HIV-1活性与其Rl活性显著 相关,但似乎又不是唯一的决定因素;TCS C末端氨基酸的突变影响其抗HIV.1活性;在C末端增加KDEL信号肽 序列及19aa尾肽并不能增加其抗HIV活性;抗原决定簇突变体以及PEG20K偶联TCS抗原决定簇突变体体外抗 HIV-1活性下降;抗HIV.1机制可能与对感染细胞的间接作用有关。
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天花粉蛋白(Trichosanthin,TCS)是从葫芦科植物括楼(TrichosanthesKiriloii)球根中提取的一种由247个氨基酸组成的I型核糖体失活蛋白(RibosomeInactivatingProtein,RIP)。TCS具有广谱的生物学和药学活性,包括抗肿瘤、免疫抑制、中期引产以及抗病毒活性,TCS还具有抗白血病和淋巴瘤的作用。TCS能够抑制HI卜1在急性感染的T淋巴细胞和慢性感染的巨噬细胞中的复制。TCS抗HIV的机制还不清楚,一般认为与R1(RibosolneInactivating)活性有关。TCS的毒副作用限制了它在抗HIV/AIDS临床上的进一步应用。人们期望通过改造或修饰,在保留TCS抗HIV活性的同时,降低其神经毒副作用及所引起的变态反应。因此,研究TCS的抗HIV-1作用机制及构效关系,有利于拓宽TCS的临床应用适应症,也对RIP类化合物基础研究和应用研究具有重要的指导作用。本论文在实验室己有研究工作的基础上,对TCS抗HIV-1作用、机制及构效关系进一步研究。首先,采用MTT比色法检侧TcS对人T淋巴细胞系C8166、HIV-1慢性感染细胞系H9/HIV-1IIIB细胞毒性作用以及采用台盼蓝染色法检测了TCs对刺激转化的人外周血单个核细胞(PeriphejralBloodMononuclearCen,PBMC)的细胞毒性作用;以合胞体形成抑制实验检测了TCS对实验株HIV-1ms诱导C8166细胞致细胞病变的抑制作用;以捕捉HIV-1p24抗原ELISA方法检测TCS对实验.株HIV-1IIIB在急性感染C8166,细胞和慢性感染Hg细胞中复制的抑制作用、临床分离株HIV-1KMO18在PBMC中复制的抑制作用、耐药株HIV-174v在C8166细胞中复制的抑制作用。其次,利用荧光实时定量RT-PCR检测了TCS对HIV-IIIB吸附和融合宿主细胞的抑制作用;采用高效液相色谱(HighPerformanceLiquidChromatograPhy,HPLC)检测了TCS脱HIV-IRNA腺嘿呤作用;另外还检测了TCS对病毒颗粒的直接杀伤作用、TCS对HIV感染和未感染细胞融合的抑制以及对HIV重组逆转录酶活性的抑制作用。最后,利用以蛋白工程技术构建的14个TCD突变体研究其抗HIV的构效关系,其中活性中心突变体:结果表明,TCS不仅能够有效抑制实验株HIV-1mB在C8166细胞中的复制和HIV-1ms诱导宿主细胞的病变作用,还能抑制临床分离株HIV-1KM018在PMBC中的复制和耐药株HIV-174v在C8166细胞中的复制,但TCS对HIV-1在慢性感染H9细胞中的复制无直接抑制作用。TCS不能抑制HIV-1进入宿主细胞;对感染细胞和未感染细胞的融合没有抑制作用;TCS也不能抑制HIV-1重组逆转录酶活性;TCS对病毒颗粒的直接杀伤作用不大;但TCS能够使裸露的HIV-1RNA脱腺漂呤,可能TCS的脱缥岭活性或其它酶活性直接损伤病毒或者病毒感染细胞的核酸,而胞质腺嗦岭含量的增高则可以导致线粒体膜电位的降低、细胞色素C的释放、活性氧的增加和抗凋亡因子表达的下降,结果使感染细胞更多的凋亡,这可能是TCS抗HIV的一个机制。结果也表明,活性中心突变体TCSM(120-123)与TCSE160A/E189A,在失去绝大部分R工活"性的同时,也几乎完全失去抗HIV活性。、而另一个活性中心突变体TCSR122G,RI活性下降1的倍,却仍保留一定的抗HIV活性。TcSC末端删除突变体(TCSC2,TCSC4和TCSC14)抗HIV活性的下降(1.4-4.8倍)与其R1活性呈平行下降(1.2-3.3倍)。这些结果表明TCS抗HIV-1活性与其R1活性显著相关,但似乎又不是唯一的决定因素,因为我们发现二个分别在C末端加上末端19个氨基酸延伸肤或KDEL信号肤的突变体TCS饥触与TCSKDEL,虽然保留全部的RI活性,但却几乎完全失去抗HIV活性,表明有其它机制介入了TCS的抗HIV-1活性。TCS抗原决定簇位点突变后对TCS抗HIV-1活性没有显著影响,但当在抗原决定簇突变体所引入的Cys残基上加上PEG漱后,这些突变体则显著降低了抗HIV-1的活性。
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近二十多年来,基于对臭氧层衰减、紫外线B(UV-B)增强的担心,研究者希望了解到紫外线辐射对不同作物的影响情况,增强UV-B辐射条件下是否对作物的生长发育、产量质量构成威胁。在本试验中,我们首先探讨了双子叶作物黄瓜(Cucumis sativus)和大豆(Glycine max)对不同紫外波段的生物效应[分别为B-UVA(315-400 nm),N-UVA(315-340 nm),B-UVB(275-400 nm)和N-UVB(290-340 nm),UV-(>400nm)作对照]。我们观察到所有的UV波段处理都使黄瓜和大豆的生长受到抑制,并且细胞受到不同程度的氧化伤害;UV波段处理的作用效果与不同波段的紫外有效生物辐射剂量有关。处理差异在UV-B波段内部和UV-A波段内部同样存在。植物生长UV辐射公式(BSWF)能很好的预测本试验UV-B波段内的平均植物效应,但不能预测UV-A波段的植物效应。短波UV-A的生物作用强于长波UV-A。光合色素的变化与UV波谱差异和种间差异有关。在高的紫外/可见光背景下,UV-A处理同UV-B同样导致光合色素的降低,但黄瓜类胡萝卜素/叶绿素比例升高。与其他研究者的试验结果比较后,我们认为紫外线B辐射的生物效应一致性很高,但紫外线A波段的生物学效应存在较大争议。因此我们在本试验的基础上仅进行荞麦[苦荞(Fagopyrum tataricum Gaertn.)和甜荞(Fagopyrum esculentum Moench.)]对紫外线B波段的响应研究。 我们对苦荞品种-圆籽荞进行了连续两个生长季节的大田半控制试验以观察UV-B辐射对苦荞生长、发育、产量及叶片色素的影响;试验小区进行降低UV-B、近充足UV-B和增强UV-B辐射处理。我们的试验表明在不同强度UV-B辐射下苦荞的生长、地上部生物量积累及最终产量都有所下降,但苦荞的发育加快;当前条件下的日光紫外线B辐射对植物生长和产量也造成负面影响。植物光合色素被日光及增强UV-B辐射降低;UV化合物及卢丁含量在中低剂量的UV-B辐射强度下显著升高,但在高剂量的增强UV-B辐射下短期升高后迅速下降。我们的试验表明苦荞是一个对UV-B高度敏感的作物。苦荞对UV-B的敏感性与UV-B剂量、外界环境因素及生长季节有关。 单个苦荞品种的试验结果使我们认识到外界UV-B辐射已经对苦荞生长发育构成逆境条件,未来全球气候变化条件下增强紫外线B辐射可能使其处于更不利的生长环境中。因此我们有进行了多个种群进行UV-B响应观察并筛选耐性种群。我们对15个苦荞种群进行增强UV-B辐射处理(6.30 kJ m2 UV-BBE,模拟当地25%的臭氧衰减),我们观察苦荞UV-B辐射效应存在显著的种内差异,UV-B辐射对多数种群具有抑制作用,但对一些种群还有刺激作用。我们采用主成分分析方法与作物UV-B响应指数(RI)来评价苦荞作物UV-B辐射耐性。我们发现作物的UV-B耐性不仅与其原产地背景UV-B强度有关,而且与作物相对生长效率、次生代谢产物含量(如卢丁)及其他因素有关。我们观察到苦荞伸展叶总叶绿素变化与UV-B耐性成正相关;室内苦荞幼苗的UV-B辐射致死试验表明:苦荞种群死亡率与其UV-B耐性成负相关。 此外,我们对甜荞的UV-B辐射响应也进行了初步研究。选取美姑甜荞、巧家甜荞和云龙甜荞进行5个梯度的增强UV-B辐射室外模拟试验。我们观察到UV-B辐射显著降低了甜荞的生长、生物量及产量;并严重影响了甜荞的生殖生长,降低了花序数、种子数和结实率;并且UV-B辐射对甜荞的抑制作用存在显著的剂量效应。三种甜荞品种存在显著的种内差异,其中美姑品种UV-B耐性最强,且膜脂受UV-B辐射氧化伤害最小,这与该品种UV-B辐射下较高的GR酶活性、APX酶活性和PPO酶活性、以及含量更高的抗坏血酸有关。甜荞的次生代谢也受到增强UV-B辐射的影响,其香豆酰类化合物在UV-B辐射下升高显著,而槲皮素含量也在高剂量UV-B辐射下有所增加;卢丁含量依赖UV-B辐射剂量而变化,中低剂量UV-B辐射下其卢丁含量逐渐升高,但在高剂量辐射下逐渐下降。 通过对生长在高海拔地区的荞麦作物(苦荞和甜荞)进行的室外研究,我们认识到作物不同品种存在很大的耐性差异,这就为UV-B耐性育种创造了有利条件。进一步加大荞麦种质资源筛选力度并深入认识荞麦抗性机理,在此基础上通过杂交或其他基因融合手段培育抗性品种,对高剂量UV-B辐射地区的荞麦产量的提高将起到重要推动作用,并使荞麦生产能有效应对未来全球气候变化条件下UV-B辐射可能升高的威胁。 During last few decades, due to concern of ozone layer depletion and enhancement of ultraviolet B radiation(UV-B, 280-315 nm), the agronomist want to know the responses of different crop species to UV-B. In the first experiment of our study, the effect of different UV band [B-UVA(315-400 nm), N-UVA(315-340 nm), B-UVB(275-400 nm), N-UVB(290-340 nm)and UV-(>400nm, as control)] on the cucumber(Cucumis sativus)and soybean(Glycine max)were investigated in growth room. Spectra-dependent differences in growth and oxidation indices existed within UV-A bands as well as UV-B bands. The general biological effects of different band were UV- < B-UVA< N-UVA<N-UVB<B-UVB. The plant growth biologically spectra weighting function(BSWF)matched well with average plant response in UV-B region, but not in UV-A region. Shorter UV-A wavelength imposed more negative impact than longer UV-A wavelength did in both species. The effect on photosynthetic pigment was related to different UV bands and different species. The photosynthetic pigment content was decreased by UV-A spectra as well as UV-B spectra. In comparison with the results of previous studies, we found that the wavelength-dependent biological effect of ultraviolet B radiation has high consistency, but the biological effect of ultraviolet-A radiation was inconsistent. We narrow our following study on the effect of ultraviolet B radiation on the buckwheat(tartary buckwheat and common buckwheat). The tartary buckwheat(Fagopyrum tataricum Gaertn.)cultivars Yuanziqiao was grown in the sheltered field plots for two consecutive seasons under reduced, near-ambient and two supplemental levels of UV-B radiation. The crop growth, photosynthetic pigments, total biomass, final seed yield and thousand-grain weight were decreased by near-ambient and enhanced UV-B radiation, while crop development was promoted by enhanced UV-B radiation. Leaf rutin concentration and UV-B absorbing compound was generally increased by UV-B with the exception of 8.50 kJ m-2 day-1 supplemental levels. Our results showed that tartary buckwheat is a potentially UV-B sensitive species. Study on one cultivars showed that ambient solar radiation had present a stress to tartary buckwheat. This makes it necessary to observe the UV-B response of many cultivars and screen tolerant cultivars. Fifteen populations of tartary buckwheat were experienced enhanced UV-B radiation simulating 25% depletion of the stratospheric ozone layer in Kunming region, and plant responses in growth, morphology and productivity were observed. Principal components analysis(PCA)was used to evaluate overall sensitivity of plant response to UV-B as well as response index. The different populations exhibited significant differences in responses to UV-B. The photosynthetic pigments of young seedlings were also affected significantly under field condition. On the other hand, the healthy seedlings of different populations were exposed to the high level of UV-B radiation in growth chambers to determine the plant lethality rate. The plant tolerance evaluated by multivariate analysis was positively related to total plant chlorophyll change, but negatively related to lethality rate. In other hand, the UV-B responses of the other important cultivated buckwheat species, common buckwheat(Fagopyrum esculentum Moench.), were also studied preliminarily. Three widespread cultivated variety(Meigu, Qiaojia and Yunlong cultivars)were provided with five level of enhanced UV-B radiation outdoors. We observed that the crop growth, development and production were significantly decreased, and reproductive production, like anthotaxy number, seed number and seed setting ratio, was also decreased. Dose-dependent inhibition effect caused by enhanced UV-B radiation also existed in common buckwheat. Significant intraspecific difference existed in those three cultivars. The Meigu cultivars with dwarfed growth and lower production have highest UV-B tolerance as well as lowest damage in cell membrane, this could be associated with profound enhancements of glutathione reductase(GR)activity, ascorbate peroxidase activity and polyphenol oxidase activity as well as higher ascorbic acid concentration. The secondary metabolism was also affected by UV-B radiation, with profound elevation of coumarin compound and moderate increase of quercetin concentration. Rutin concentration was peaked in 5kJ m-2 UV-B. The contrasting effect of UV-B radiation on different populations indicated that there existed abundant genetic resources for selecting tolerant populations of common and tartary buckwheat. Much effort needed be pose on screening of buckwheat germplasm and clarification of mechanism of buckwheat tolerance to UV-B. On this base the tolerant cultivars could be bred by hybridization and other gene transfusion method, this would help increase buckwheat yield in high ambient UV-B region and counteract the effect of possible enhanced UV-B radiation in future.
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A new measurement of proton resonance scattering on Be-7 was performed tip to the center-of-mass energy of 6.7 MeV using the low-energy RI beam facility CRIB (CNS Radioactive Ion Beam separator) at the Center for Nuclear Study of the University of Tokyo. The excitation function of Be-7 + p elastic scattering above 3.5 MeV was measured Successfully for the first time, providing important information about the resonance structure of the B-8 nucleus. The resonances are related to the reaction rate of Be-7(p.gamma)B-8. which is the key reaction in solar B-8 neutrino production. Evidence for the presence of two negative parity states is presented. One of them is a 2(-) state observed as a broad s-wave resonance, the existence of which had been questionable. Its possible effects on the determination of the astrophysical S-factor of Be-7(p.gamma)B-8 at solar energy are discussed. The other state had not been observed in previous measurements, and its spin and parity were determined as 1(-). (C) 2009 Elsevier B.V. All rights reserved.
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以东北地区33个不同来源的小麦品种为研究对象,采用琼脂共培法,评价了不同小麦品种对黑麦草所产生的化感作用.通过分析不同小麦品种对黑麦草根长、苗高、根干重及苗干重的影响,探讨不同小麦品种对黑麦草化感作用的差异,从而筛选出具有较强化感潜力的小麦品种.结果表明,不同小麦品种对黑麦草根长、苗高、根干重及苗干重的影响存在显著差异.利用R I值作为化感作用的指标,结合聚类分析方法,可将这33个小麦品种按化感能力的强、中、弱分成3类;其中龙幅麦9号、龙幅麦13号、锦麦2003和小冰麦33号为化感能力较强的品种.
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Very high-resolution seismic lines were collected offshore the Venice Lagoon in the framework of the Co.Ri.La'New very high resolution seismic methods to study the Venice Lagoon subsoil' project. The 140 km boomer profiles led to the identification of a convex-upward,lens-shaped body just outside the Lido inlet,one of the three lagoon inlets,which has been interpreted as an ebb-tidal delta.The comparison between the scismostratigraphic setting og this deposit, as revealed by the seismic lines,and the analyses of historicalbathymetric maps highlighted the key role of human interventions in the formation and evolution of the Lido inlet cbb-tidal delta.To preserve the lagoon environment but also to ensure a navigable way, human interventions at the Lidoinlet,performed since the fourteenth centtury, caused profound variations in the inlet dynamics,ldading to a progressive increase in the sediment dispersion from the lagoon interior towards the sea. The ebb-tidal delta of the Lido nilet is thus a very recent feature compared with the formation of the Venice lagoon and formed mainly as a consequence of the construction of the two jetties that have bound the inlet form AD 1886 to the present day.
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以长白山阔叶红松林为研究对象 ,利用长白山阔叶红松林气象观测塔安装的常规气象梯度观测系统、开路涡动相关系统的观测数据 ,依据空气动力学基本理论与能量平衡方程建立了森林蒸散机理模型 ,确定了模型参数 ,即风速廓线稳定度订正函数 φm、温度廓线稳定度订正函数 φh 和零平面位移高度d .其中 ,研究地的零平面位移高度d为 17.8m ,是平均冠层高度 ( 2 6m)的 0 .6 8.同时 ,给出了 φm 和 φh 随梯度理查逊数Ri 变化的数学表达式 .
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针对RI系统的污染物去除机制、运行方式、系统恢复以及实践应用等方面的研究进展作一综述。RI技术的应用有着广阔的前景 ,必将促进我国环境保护与生态建设的发展
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A rapid and simple analytical method was developed for the simultaneous and quantitative determination and separation of hydrophilic imidazolium ionic liquids (ILs) (1-butyl-3-methylimidazolium chloride, [C(4)mim]Cl; 1-hexyl-3-methylimidazolium chloride, [C(6)mim]Cl; 1-octyl-3-methylimidazolium chloride, [C(8)mim]Cl; 1-allyl-3-methylimidazolium chloride, [Amim]Cl; or 1-allyl-3-methylimidazolium bromide, [Amim]Br) with miscible ethyl acetate and EtOH and their mixtures using reverse phase liquid chromatography coupled with refractive index detection (RPLC-RI). The influence of 60 to 100% (volume percentage) methanol in the mobile phase on the IL systems ([C(4)mim]Cl, [C(6)mim]Cl, [C(8)mim]Cl, [Amim]Br, or [Amim]Cl)-ethyl acetate-EtOH was investigated.
Resumo:
Amphiphilic biodegradable star-shaped polymer was conveniently prepared by the Sn(Oct)(2)-catalyzed ring opening polymerization of c-caprolactone (CL) with hyperbranched poly(ester amide) (PEA) as a macroinitiator. Various monomer/initiator ratios were employed to vary the length of the PCL arms. H-1 NMR and FTIR characterizations showed the successful synthesis of star polymer with high initiation efficiency. SEC analysis using triple detectors, RI, light scattering, and viscosity confirmed the controlled manner of polymerization and the star architecture.
Resumo:
A new algorithm for computer perception of topological symmetry is proposed. A node library containing various kinds of nodes is built, and the index number of the library is used as initial atom class identifier (CI) to discriminate the different types of non-hydrogen atoms. The path index (PI) and ringindex (RI) are calculated from the CI, and the global topological enviroment is defined as the sum of PIs and RIs. The topological symmetry can be detected by the iterative calculation of the global topological enviroment.
Resumo:
沉积物再悬浮作为一个比较普遍的物理现象,对浅海生态系统污染物的生物地球化学循环具有强烈的干扰作用。本研究以我国北方重要养殖海湾——桑沟湾为研究对象,从物理、化学、生物三个角度出发,研究了沉积物再悬浮的发生过程以及再悬浮介质-沉积物的源汇转换角色及其与养殖藻类的关系,构建了波流耦合模型和再悬浮颗粒物浓度预测数学模型。主要研究结果如下: 1)桑沟湾的海湾动力比约为1.54,沉积物具有发生再悬浮的潜在动力条件;推导出波流耦合切应力的计算公式。 2)悬浮颗粒物浓度(SSC)与浊度(NTU)之间符合线性方程SSC=15.908×ln(NTU)+7.0888(n=33,R2=0.7209);碎屑有机碳库是桑沟湾养殖生态系统中最大的有机碳库,占总POC库储量的81.87%。 3)沉积物再悬浮的临界切应力在0.059 N/m2左右,耦合切应力与悬浮颗粒物浓度符合方程= 238.06 SSC + 25.215(n=25,R2 = 0.7298);最大剪切深度可达8.81 cm;桑沟湾沉积物再悬浮通量的数量级在10-5~10-6 kg·m-2·s-1之间,再悬浮临界风速约为5.51 m/s,全年约有171天沉积物处于再悬浮状态;构建了沉积物再悬浮颗粒物浓度预测数学模型。 4)桑沟湾表层沉积物总氮的含量范围313.09~1094.44µg/g,有机氮是总氮的主要形态,平均占总氮的60.86%;交换态氮是无机氮的主要形式,平均占无机氮的71.40%,交换态氮中NO3--N的含量最大;桑沟湾表层沉积物的TOC/TN比值为9.38,表明沉积物中有机质具有混合来源的特征;无机磷是桑沟湾表层沉积物中磷的主要形态,平均占总磷的73.33%,钙结合磷是无机磷的主要赋存形态;表层沉积物中潜在生物有效性磷的含量占总磷的86.54%,具有很强的释磷潜力。桑沟湾重金属的潜在生态危害指数RI约为36.17,表明重金属的潜在生态危害轻微。 5)再悬浮过程中沉积物春季表现为氮磷源,释放溶解无机氮和磷酸盐;夏、秋季表现为氮汇磷源,释放磷酸盐而吸附溶解无机氮;冬季表现为氮磷汇,吸附磷酸盐和溶解无机氮。