SOME ASPECTS OF THE GROWTH OF GRACILARIA-TENUISITIPITATA IN POND CULTURE

The effect of temperature, salinity, nitrogen, culture density and depth on the growth of Gracilaria tenuistipitata were investigated between April 1985 and March 1986 in outdoor ponds in Guangxi Province, South China. The mean annual growth rate was 2.4% per day. Under favourable temperatures of 20-30-degrees-C, daily growth rate may reach as high as 3.3%. Salinity had an obvious effect on growth and photosynthesis and growth peaked at 21 parts per thousand, with a broad plateau between 7-27 parts per thousand. Growth experiments showed that a total nitrogen (NH4-N plus NO3-N) concentration of 4 muM was sufficient to enable the plants to maintain a daily growth rate of 2.7%. The best growth of the plant was obtained at a culture density of 0.5-1 kg M-2 and a culture depth of 30 cm in the pond.

Clay mineral distributions in the southern Yellow Sea and their significance

To better understand the characteristics of the clay minerals in the southern Yellow Sea, the X-ray quantitative determinations have been carried out for the surface samples obtained from the Yellow Sea. With newly compiled clay mineral synoptic maps, the depositional processes were described for four main clay minerals (illite, chlorite, kaolinite and smectite). The analysis shows that most clay minerals are of terrigenous source with the Huanghe River acting as the major sediment supplier. Besides, the source of muddy sediments in the Yellow Sea was also discussed. As for the central Yellow Sea mud (CYSM), the sediments in its northern part mainly come from the Huanghe River, and those in the rest are of multi-origin. Very similarly, a large amount of sediments in the northern part of the southeastern Yellow Sea Mud (SEYSM) derive from the Keum River and Yeong-san River, while those in the southern part are of multi-origin.

热海水中高效铝基牺牲阳极的研制

随着社会的高速发展和人口急剧增加，淡水资源危机问题已引起世界各国的普遍关注。我国属于贫水国家，部分地区淡水资源严重缺乏，沿海城市尤为严重。据统计，城市用水中约80%为工业用水，工业用水中约80%为工业泠却用水。针对这种情况，人们试图在工业生产中用海水代替淡水做工业冷却水，以节约淡水资源。然而，在海水冷却系统中，换热器的出口及其后续部位的钢铁设施由于海水温度较高，一般50℃左右，有的还大于55℃，腐蚀特别严重。因此，解决该部位的腐蚀防护问题是直接利用海水代替淡水做工业冷却用水中不可缺少的一环。牺牲阳极法是防止海水中钢铁设备腐蚀的一种行之有效的方法，但是常用的几种牺牲阳极在该温度下电流效率明显降低。因此研究一种能在较高温度下（50℃左右）使用的新型高效牺牲阳极是一项很有意义的工作。这也是本课题的研究目的。本文自制了28种Al-Zn-In系牺牲阳极，按国标GB 4950-85的要求测试了开路电位、工作电位；计算了电流效率；观察了腐蚀产物脱落情况及腐蚀均匀性，结果表明腐蚀均匀性是影响高温铝基牺牲阳极性能的最主要因素。进一步测试了三种试样的恒电流阳极极化曲线，结果表明，牺牲阳极阳极极化时，在开始的0.2（或0.4）mA/cm~2较小的阳极极化电流下，极化程度最大，随后尽管增加阳极极化电流，极化电位基本维持稳定；随着温度的升高，极化程度也越来越大，说明温度升高，会使牺牲阳极的工作电位正移，不利于提供足够的保护电位。用灰箱分析法研究了各元素与工作电位、电流效率、腐蚀产物均匀性的关联性。结果表明，对提高牺牲阳极的腐蚀均匀性来说，在20℃、40℃时，Mg是合适的添加元素；在60℃时，Ga是合适的添加元素。根据灰箱分析结果，建议牺牲阳极配方：20℃、40℃时，为Al-Zn-In-Ga-Mg；60℃时为Al-Zn-In-Ga。

Sources and transport of dissolved and particulate organic carbon in the Mississippi River estuary and adjacent coastal waters of the northern Gulf of Mexico

Dissolved organic carbon (DOC), stable carbon isotopic (delta(13)C) compositions of DOC and particulate organic carbon (POC), and elemental C/N ratios of POC were measured for samples collected from the lower Mississippi and Atchafalaya rivers and adjacent coastal waters in the northern Gulf of Mexico during the low flow season in June 2000 and high flow season in April 2001. These isotopic and C/N results combined with DOC measurements were used to assess the sources and transport of terrestrial organic matter from the Mississippi and Atchafalaya rivers to the coastal region in the northern Gulf of Mexico. delta(13)C values of both POC (-23.8parts per thousand to -26.8parts per thousand) and DOC (-25.0parts per thousand to -29.0parts per thousand) carried by the two rivers were more depleted than the values measured for the samples collected in the offshore waters. Strong seasonal variations in delta(13)C distributions were observed for both POC and DOC in the surface waters of the region. Fresh water discharge and horizontal mixing played important roles in the distribution and transport of terrestrial POC and DOC offshore. Our results indicate that both POC and DOC exhibited non-conservative behavior during the mixing especially in the mid-salinity range. Based on a simple two end-member mixing model, the comparison of the measured DOC-delta(13)C with the calculated conservative isotopic mixing curve indicated that there was a significant in situ production of marine-derived DOC in the mid- to high-salinity waters consistent with our in situ chlorophyll-a measurements. Our DOC-delta(13)C data suggest that a removal of terrestrial DOC mainly occurred in the high-salinity (>25) waters during the mixing. Our study indicates that the mid- to high- (10-30) salinity range was the most dynamic zone for organic carbon transport and cycling in the Mississippi River estuary. Variability in isotopic and elemental compositions along with variability in DOC and POC concentrations suggest that autochthonous production, bacterial utilization, and photo-oxidation could all play important roles in regulating and removing terrestrial DOC in the northern Gulf of Mexico and further study of these individual processes is warranted. (C) 2004 Elsevier B.V. All rights reserved.

Concentrations and distribution of organochlorine pesticides in shellfish from Changjiang estuary

To analyze and evaluate the status of organochlorine pollutants in the Changjiang (Yangtze River) estuary and adjacent waters, the concentrations of hexachlorocyclohexane (HCHs) and dichlorodiphenyltrichloroethane (DDTs) in shellfish collected in study area from 2006 to 2007 were determined with gas chromatography (GC). The concentration range of HCHs was (ND-12.13)x10(-3) mg/kg wet weight and averaged at 0.54x10(-3) mg/kg while the concentration of DDTs was in the range of (4.06-281.73) x10(-3) mg/kg with a mean of 57.52x10(-3) mg/kg in the survey areas. The concentrations of DDTs in the shellfish were higher than HCHs', so that DDTs could be considered as typical organochlorine pollutants in the areas. The concentrations of DDTs in the shellfish were higher than HCHs', so that DDTs could be considered as typical organochlorines pollutants. The HCHs in all the shellfish conformed to the first level of criterion (0.02 mg/kg) of the Marion Biology Quality (GB 18421-2001), and that of DDTs in most samples were beyond the first level (0.01 mg/kg) but conformed to the second level (0.10 mg/kg). On average, alpha-HCH and delta-HCH occupied the most part of HCHs, while O,P'-DDT and P,P'-DDT occupied the most part of DDTs. The concentrations of organocholorine pesticides in shellfish samples varied in site and in species. The highest level occurred at the Shengsi (SS), followed by Yangkougang (YKG), Lvsi (LS), Dongyuan (DY) and Beibayao (BBY), low concentrations were observed at Changsha (CS), Beidaodi (BDD), and Gouqi (GQ). The concentration of HCHs and DDTs in most sites decreased clearly from 2006 to 2007 except for YKG, DY, BDD, LYS, and SS. All of above results suggested that the study area was slightly affected by organochlorine pesticide, special by DDTs.

苏里格气田苏6加密井区山1-盒8层段河流沉积体系分析

Sulige gas field is located in Northwest of Yi-Shan Slope of the Ordos Basin. The Shan 1 Member of the Shanxi Formation and He8 Member of the ShiHeZi Formation are not only objective strata of research but also main producing strata of the Sulige Field. From core and wireline log data of 32 wells in well Su6 area of Sulige field, no less than six lithofaice types can be recognised. They are Gm,Sl,Sh,Sm,Sp,Fl,Fm. Box-shaped, bell-shaped, funnel-shaped and line-segment-shaped log are typcial gamma-ray log characters and shapes. The Depositonal system of the Shan1-He8 strata in research area have five bounding-surface hierarchies and was composed of six architectural elements, CH, LS,FF（CH）,SB,LA,GB. The depositional model of Shan 1 was the type of a sandy meandering river with natural levee, abandoned channels and crevasse splay. Channel depth of this model maybe 7-12 m and the fullest-bank flow can reach 14 m high. Based on analysis of depositional causes, a sandy braided river model for the depositional system of He 8 can be erected. It consists of active main channels, active chute channels, sheet-like sand bars, abandoned main channels and abandoned chute channels. Channel depth of this model can be 3-4 m with 9 m of highest flow. Six gamma-ray log cross sections show that the connectivity of sandbodies through Shan 1 Member is lower than He 8. Influenced by occurrence of mudy and silty deposits, vertical connectivity of sandbodies through He 8 is not high.

辣椒氟平均含量及其影响因素研究

西南地区是我国燃煤污染型氟中毒流行最为严重的地区，同时也是我国主要辣椒优异种质资源的分布地之一。大量的研究已经证明，辣椒和玉米等食物在用煤火烘干过程中可以吸收富集燃煤过程释放到大气中的氟，因此由燃煤型氟污染引起的食物型氟中毒也不断受到关注。 国内外至今缺乏对辣椒氟的背景值、平均含量以及影响其含量变化的因素的系统研究，只有部分研究者对燃煤型地方性氟中毒地区的辣椒进行了零星的调查分析，所采样品具有很大的局限性，远远不能代表辣椒整体的氟含量水平；且国内外迄今尚无辣椒氟含量的卫生标准，由于辣椒与其他食物和蔬菜相比具有其特殊性，而目前国家有关食品中氟的限量标准（GB2762-2005）对辣椒而言明显不合适，因此只有在对辣椒中氟的含量进行充分调查研究，才能有针对性地制定出更为科学合理的卫生标准，才能为辣椒是否受到氟污染的判别及防止辣椒氟污染提供理论依据。本研究的目的、方法、结果及结论如下所示。 目的：调查我国西南部分地区新鲜辣椒及干辣椒的氟含量水平，了解辣椒中氟的分布规律，进而确定新鲜辣椒中氟的污染判别值并探讨辣椒氟污染的防治措施。方法：按照《食品中氟的测定》（GB/T 5009.18-2003）方法对采自西南77个县市的新鲜辣椒（176个）及干辣椒（296个）进行氟的含量测定，根据地区、辣椒品种、干燥方式、储存时间及赋存状态，对辣椒中氟的含量进行统计分析。结果：采自农田的新鲜辣椒氟的几何平均含量为8.9mg•kg-1（干重，176个样，置信度95％），干辣椒样品氟的几何平均含量为19.6mg•kg-1（干重，296个样，置信度95％）。结论：研究证实辣椒的干燥与储存方式不当是导致辣椒氟污染的主要原因；通过对新鲜辣椒中氟含量的研究，证实我国现行的食品中氟限量标准(GB2762-2005)并不适用于辣椒，建议以24.7mg•kg-1 (干重)、5.2mg•kg-1 (鲜重)为新鲜辣椒氟污染判别值。

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with a matrix of carbon nanotubes for the analysis of low-mass compounds in environmental samples

The use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for environmental analysis has been mainly focused on qualitative analysis of high-mass molecules, such as toxins, humic acid, and microorganisms. Herein,we describe a novel MALDI-TOF-MS method with a matrix of oxidized carbon nanotubes for analysis of low-mass compounds in environmental samples. A number of chemicals in the environment were qualitatively analyzed by the present method, and it was found that most of them, especially the highly polar chemicals, were measurable with high sensitivity. With the intrinsic ability to measure high-mass chemicals, this method can compensate for the current shortage of methods for environmental analysis for the measurement of highly polar or high-mass chemicals. For sample analysis, arsenic speciation in Chinese traditional medicines was qualified and diphenylolpropane in water samples was quantified. With the relatively high tolerance of the method to interfering molecules, a simple pretreatment or even no pretreatment could be employed before MS detection. Furthermore, this method can be employed in a high-throughput format.