硫酸盐的测定——交流示波极谱滴定在海水分析中的应用(Ⅱ)   总被引：1，自引：0，他引：1  

李静  周曾昊  康代温 《中国海洋大学学报(自然科学版)》1991,(1)

采用交流示波极谱滴定法研究海水中硫酸盐的直接测定法。在pH8的乙二胺—盐酸底液中,以标准K_2Cr_2O_7溶液滴定适当过量的钡,由微过量的Cr_2O_7~(2-)(或CrO_4~(2-))在交流示波极谱图上产生的切口指示滴定终点。方法准确快速.测定标准海水和卤水中的SO_4~(2-)的回收率分别为98.11±0.67和100.03±1.1％。相对标准偏差小于1％。  相似文献   

Effects of potassium sulfide content in marine diesel fuel oil on emission characteristics of marine furnaces under varying humidity of inlet air   总被引：1，自引：0，他引：1  

Cherng-Yuan Lin  Wei-Cheng Chen 《Ocean Engineering》2006,33(8-9):1260-1270

Degraded fuel oils are generally used in marine power plants for economic purposes, so as to reduce operating expenses. These marine fuel oils commonly contain various oxides or sulfide compounds of metallic elements in the fuel ash, and affect the combustion and emission characteristics of marine power plants to different extents. Moreover, marine power plants are more often operated in a highly humid environment. As a result the emission and burning process may also be altered by the various humidity level of the inlet air. The effects of potassium sulfide in marine diesel on the combustion and emission characteristics of marine furnaces under varying levels of relative humidity of inlet air were experimentally investigated in this study. A cylindrical industrial furnace made of AISI 316 stainless steel, and an automatic oil-fired burner were used for the emission characteristics measurements and observation. A mechanically homogenizing machine was used to stir potassium sulfide (K₂SO₄) powder and marine diesel with a preset K₂SO₄ concentration. The relative humidity of the inlet air and temperature were adjusted to their assigned values by a large-size air conditioner before being pumped into the burner. The marine diesel oil mixture was atomized by the inlet air consequently ignited by an electrode and then burned within the horizontal furnace. There were eight rectangular slots cut in the upper portion of the furnace wall so that the probes of a gas analyzer and a thermocouple could be inserted into radial positions in the cylindrical furnace. The concentrations of gas emission and burning gas temperature and the combustion efficiency were analyzed. The experimental results show that the burning gas temperature, carbon dioxide emission and combustion efficiency decreased when the concentrations of excess air and oxygen emission increased with the addition of potassium sulfide in the marine diesel fuel. This is primarily attributed to the fact that the sulfide of an alkali compound such as K₂SO₄ may suppress the oxidation reaction process, leading to inferior combustion characteristics.  相似文献   

The Increase of Biogenic Sulfate Aerosol and Particle Number in Marine Atmosphere over the Northwestern North Pacific     

Atsushi Ooki  Kazuhiko Miura  Mitsuo Uematsu 《Journal of Oceanography》2003,59(6):799-807

During a cruise aboard the R/V Hakuho-maru in the northwestern North Pacific in the summer of 1998 the particle number concentrations and the major ionic components of size fractionated aerosols were measured to investigate the aerosol produced by marine biological activity. Continuous low concentrations of nitrate (<1.8 nmol m⁻³), similar to the marine air background level, were found over the northwestern North Pacific (40–45°N) and the Sea of Okhotsk (44–45°N). Over the Sea of Okhotsk, a high concentration of chlorophyll-a (5.4 mg m⁻³) in seawater was observed, and atmospheric concentrations of non sea-salt (nss-) sulfate (44 nmol m⁻³), methane sulfonic acid (MSA) (1.8 nmol m⁻³) and particle number in the size range of 0.1 < D < 0.5 μm (199 cm⁻³) were found to be 9, 7, and 2 times, respectively, higher than those in the background marine air. The increase in particle number concentrations mainly in the size range of 0.2 < D < 0.3 μm was likely caused by the increase of biogenic sulfate over the high productive region of the Sea of Okhotsk. In humid air conditions (R.H. > 96%), the increased biogenic sulfate that condensed the large amount of water vapor would not have sufficient solute mass to activate as cloud condensation nuclei (CNN) and would remain as aerosol particles in the marine air with frequent sea-fogs over the high productive region. Biogenic sulfate originating from dimethyl sulfide (DMS) would gradually grow into the CCN size and continuously supply a great number of CCN to the marine air in the northwestern North Pacific. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

The effects of sodium sulfate on the emissions characteristics of an emulsified marine diesel oil-fired furnace     

Cherng-Yuan Lin  Jenq-Yih Pan 《Ocean Engineering》2001,28(4)

Degraded diesel oils are commonly used in marine power plants to conform to the demands of shipowners for fuel economy. The burning of these marine fuel oils, which frequently contain various extents of oxides of iron, silicon, calcium, vanadium and potassium, such as Na₂SO₄, Fe₂O₃, SiO₂, CaO, V₂O₅, etc., are susceptible to form much more complex compounds of either gaseous or solid phases. The release of these emissions to the environment may cause atmospheric pollution and a health hazard to human beings. Emulsification of a fuel oil with water to produce a micro-water-particles-dispersed-in-oil (W/O) emulsion has been considered as one of the promising techniques to improve combustion characteristics of low-grade marine oils and in turn effectively help to reduce the release of air pollutants. Marine fuel oil A, which approximates ASTM No. 2D oil was used as the test oil and the surfactant Span 80 was used to promote the affinity and integrating force between the components of the emulsion. An emulsifying/homogenizing machine was employed to stir the emulsion mixture of the marine oil, distilled water, surfactant Span 80 and sodium sulfate (Na₂SO₄) powder of 300 ppm. The mechanically blended emulsion mixture was injected, atomized and burned in an oil-fired furnace using an automatic burner. Burning gas composition, burning efficiency and gas temperature were measured and analyzed. Compared to neat marine diesel oil, W/O emulsions had higher combustion efficiencies, higher concentrations of O₂ and SO₂, while gas temperatures were lowered and CO and NO_x production was reduced. The addition of sodium sulfate decreased combustion efficiency and NO_x concentration and increased O₂, CO, and SO₂ concentrations.  相似文献   

KCl+KHCO_3水溶液中氯化钾的平均活度系数和KHCO_3~0的缔合常数     

陈国华  季荣  薛小平  陈颖 《中国海洋大学学报(自然科学版)》1993,(3)

用钾离子选择电极和银—氯化银电极构成的无液界电池测量了KCl+KHCO_3混合水溶液中KCl的平均活度系数,发现其活度系数的对数与混合溶液中KHCO_3的浓度m_2服从哈奈特关系式。用最小二乘法计算机处理求得了各离子强度条件下相应的哈奈特系数。还用适用于混合电解质溶液的皮茨公式计算了该体系电解质的平均活度系数和溶液的超额自由能,计算出活度系数与实验值之间的平均标准偏差为±0.006。溶液的超额自由能随溶液组成变化表明,对于有相同阳离子(K~+)的该混合溶液中离子间短程作用力主要受Cl~-作用的影响。用累代逼近法用微机计算,求得了KHCO_3~0的化学计量缔合常数经验公式及其热力学缔合常数。  相似文献   

海藻硫酸多糖911抗乙脑病毒作用的观察     

王文涛  李钟铎  邢善田  周金黄  管华诗 《中国海洋大学学报(自然科学版)》1992,(Z1)

采用体外微量细胞病变抑制实验及体内半数致死量LD_(50)测定法,分别观察海藻硫酸多糖911对乙型脑炎病毒的作用。结果表明,海藻硫酸多糖911在体外适宜的浓度条件下,对乙型脑炎病毒有一定的抑制作用,但对病毒无中和作用。体内给药,911对乙型脑炎病毒无明显抑制作用。  相似文献   

海洋硫酸多糖916氧化降解条件的正交实验法优化   总被引：1，自引：0，他引：1  

韩玉红  吕志华  王远红  吕蓓蓓 《海洋湖沼通报》2007,(4):116-119

以分子量为考查指标,采用正交实验法研究了海洋硫酸多糖916的氧化降解最佳条件。考察了H2O2浓度、原料用量和反应时间对降解后分子量的影响。结果表明,最佳降解条件为体系中H2O2浓度为3%,原料用量为2%,反应时间为3h。该法简单易行,操作简便,所用试剂廉价易得,是一种简单有效的降解方法。  相似文献   

细胞外钙和钾离子对调节离体鲤脑垂体促性腺激素分泌的影响     

林信伟  李英文  林浩然 《海洋与湖沼》1995,26(3):295-301

作者于１９９０年９月－１９９１年１月采用离体灌流培育方法对鲤鱼脑垂体促性激素的分泌调节进行研究。结果表明，脑垂体基础促性腺激素（ＧｔＨ）分泌不依赖于细胞外钙离子（Ｃａ＾２＋）；但脉冲式鲑鱼促性腺激素释放激素（ｓＧｎＲＨ）刺激的ＧｔＨ分泌，则依赖于细胞外Ｃａ＾２＋且细胞外Ｃａ＾２＋的作用至少部分通过电位敏感性Ｃａ＾２＋通道。５０ｍｍｏｌ／Ｌ高浓度钾离子（Ｋ＾＋）显著刺激脑垂体基础ＧｔＨ分泌，Ｋ＾＋的  相似文献   

On the dose dependency of the bleachable and non-bleachable components of IRSL from K-feldspar: Improved procedures for luminescence dating of Quaternary sediments     

《Quaternary Geochronology》2013

The infrared (IR) stimulated luminescence (IRSL) and post-IR IRSL (pIRIR) signals from K-feldspar can, for convenience, be divided into two components, bleachable and ‘non-bleachable’, where the latter corresponds to the ‘residual’ signal observed in sunlight-bleached samples. In this paper, we examine the non-bleachable component of IRSL of K-feldspar for several sedimentary samples from across Eurasia. We observed a large variability in the residual doses among these samples after prolonged exposure to sunlight. By employing multiple elevated temperature (MET) IR stimulations at 50–300 °C, we show that the residual dose increases systematically with stimulation temperature, attaining values as high as ∼50 Gy at 300 °C, even after several hours to tens of hours of exposure to unfiltered sunlight. We examined two samples in detail and found that the bleachable and non-bleachable components produced different dose response curves. Pulse annealing studies showed that the non-bleachable component is more stable than the bleachable component, suggesting that a preheat procedure cannot eliminate the non-bleachable component. Additional experiments revealed that the non-bleachable component is dose dependent. Owing to this dose dependency, we demonstrate mathematically and empirically that the simple subtraction of a residual dose from the measured equivalent dose (D_e) – which is the most common approach employed (if any residual dose is subtracted at all) – will result in underestimation of the actual D_e. We present a method to correct for the dose dependency of the residual dose, which can improve the accuracy of either MET-pIRIR or pIRIR age estimates for samples in which the non-bleachable component represents a significant fraction of the measured signals.  相似文献   

~(35)SO_4~(2-)示踪法测定九龙江河口沉积中硫酸盐还原速率     

尹希杰  孙治雷  徐勇航  李云海  邵长伟 《海洋学报》2015,37(4):83-93

在2011年7月利用35SO2-4培养示踪法测定九龙江河口两个站位(A站位位于咸淡混合区,盐度3~5;B站位位于海相区,盐度20~25)沉积柱中硫酸盐还原速率的垂直分布。结果显示A站位沉积柱中硫酸盐还原速率变化范围为54~2 345nmol/(cm3·d),从表层到底部先增大后减小,最大值出现在20cm深度附近;B站位硫酸盐还原速率在24~987nmol/(cm3·d)之间,分别在10cm和78cm深度附近出现两个峰值,分别为876nmol/(cm3·d)和987nmol/(cm3·d)。综合分析两个站位孔隙水中SO2-4、甲烷浓度和沉积物中总有机碳、温度和氧化还原电位的垂直变化趋势与其硫酸盐还原速率的分布规律,表明A站位沉积物中硫酸盐还原以有机矿化为主;B站位受到有机质矿化和甲烷厌氧氧化的共同作用;两个站位硫酸盐还原速率及垂直分布趋势受孔隙水中SO2-4浓度、有机质活性和温度的共同影响;根据各个层位硫酸盐还原速率估算两个站位硫酸盐还原通量(以硫计)分别为527.9mmol/(m2·d)和357.1mmol/(m2·d),表明硫酸盐还原是九龙江河口有机质厌氧矿化的重要路径。  相似文献