中国资本市场的进入:背景、条件与战略选择

当前中国资本市场在发育和成长过程中，在结构性重组以及机构多元化进程的背景下，中国企业面临进入资本市场的时机及战略选择。尽管时机千载难逢，但不同的企业应根据自身的特点和条件来决定是否进入资本市场。因为任何企业进入资本市场有利也有弊，而那些准备进入资本市场的企业，又应根据各自的情形选择不同的时机和途径，进而制订出有利于自身长期稳定扩张的市场进入战

The Determination of Polycyclic Aromatic Hydrocarbons in Sediments with ASE/GC-MS

建立了用加速溶剂萃取技术提取含硫沉积物中痕量多环芳烃的可靠方法,优化了不同萃取剂,不同提取程序等萃取条件,研究了沉积物中的硫化物对色谱分离的影响。15种多环芳烃的检出限为0.09~1.34ng/g,相对标准偏差(RSD,n=6)为12.5%~23.9%,15种多环芳烃的低浓度加标回收在74%~138%之间。高浓度加标回收率除吲哚芘为62%外,其余都在80%~122%之间。基本上达到了痕量分析的要求。用该方法分析山东半岛近岸海域沉积物中多环芳烃的含量,测得15种PAHs的总量为273~579 ng/g。与其它地区沉积物中多环芳烃含量相比,属轻/中度污染。An accelerated solvent extraction method for the extraction of polycyclic aromatic hydrocarbons(PAHs) in sediments was developed.The extraction conditions such as extraction solvent and program were optimized.The effects of sulfide on chromatographic separation were studied.The detection limits for the fifteen PAHs were 0.09-1.34 ng/g,and the relative standard deviations(RSDs) ranged from 12.5% to 23.9%.The recoveries of high level concentration ranged from 62% to 122% and those of low level concentration ranged from 74%-138%.The contents of PAHs in sediment samples collected in the coastal regions off the Shandong peninsula,China were analyzed by this method.The PAHs in these samples ranged from 273 ng/g to 579 ng/g.Overall,the PAHs levels were comparable to those reported in the literature for sediment samples collected from similar environments around the world.国家高技术研究发展计划(863)基金项目(2003AA635180);; 青岛科技将才计划基金项目(04-3-J.J-11

Distribution Characteristics of Polycyclic Aromatic Hydrocarbons in Seawater from the South Yellow Sea

2007年9月进行了2007南黄海海洋环境调查,并采集各个调查站位的表层、中层、底层海水及表层沉积物。利用液-液萃取法对采集到的样品进行前处理,并用气相色谱-质谱法检测海水中的多环芳烃。结果显示,监测站位中表层海水中总多环芳烃的含量范围是15.76--233.39ng/l,南黄海中部海水中多环芳烃的组成以2环的萘为优势组分;各种多环芳烃的含量与国际生物学组织或国家制定的评价水生生物暴露于水体的安全食用标准相比虽未超标,但个别组分如荧蒽的含量已达到生态毒理评价标准。Marine surface sediments and sea water samples from the surface, middle and bottom layers were collected from the South Yellow Sea of China.The samples were pretreated by liquid-liquid extraction and the 16 polycyclic aromatic hydrocarbons (PAHs) in the samples were determined by gas chromatography-mass spectrometry (GC-MS).The results show that the range of total PAHs is 15.76～233.39 ng/L in surface water and PAHs in the water samples from central South Yellow Sea are dominated by naphthalene (2 rings).Content of PAHs compounds don′t exceed the safety guidelines proposed by International Biology Organization or governments, but the individual compound, such as fluoranthene content has reached eco-toxicological evaluation criteria.国家海洋局节能减排专项资助;中国海监技术支撑项目资助;海洋公益性项目资助(200705011

Compressed Storage for C-Temporal Relation Data Model Based on Improved Genetic Algorithm

针对时态数据库中存在数据冗余、数据量快速增长等问题,结合现有压缩技术,提出基于改进遗传算法的C-TrdM压缩存储技术。将各个时刻的时态关系数据分解为最小粒度的数据并进行编码,采用改进的遗传算法来计算待压缩数据中的最优存储数据以提高压缩比。算法的快速收敛性使去除数据冗余的速度得到提高。There is data redundancy temporal database and the quantities of temporal database are increasing fleetly,aiming at these problems,this paper puts forward compressed storage tactics based on improved genetic algorithm for temporal data which combine compress technology in existence in order to settle data redundancy in the course of temporal data storage.Temporal relation data at any moment is decomposed into least granularity data and be coded meanwhile.Optimized storage data are figured out by using improved genetic algorithm,and the ratio of compression is enhanced.Celerity astringency of the algorithm can heighten speed of removing data redundancy largely.广西教育厅科研基金资助项目(200707LX196);广西工学院自然科学基金资助项目(院科自0704102

固相微萃取-气相色谱-质谱联用测定海水和沉积物间隙水中的痕量多环芳烃

建立了固相微萃取(SPME)与气相色谱-质谱(GC-MS)联用同时测定海水中16种多环芳烃的分析方法,研究了萃取时间、盐度条件的影响．同时用SPME的方法研究了海水中的溶解有机物(DOM)对多环芳烃萃取的影响．计算出不同DOM浓度下多环芳烃KDOM与KOW的关系: CDOM=5 mg／L时,logKDOM=0．7944KOW+0．773(R2=0．91)．CDOM=10 mg／L时,logKDOM= 0．7905KOW+0．668(R2=0．97);CDOM=30 mg／L时,logKDOM=0．714KOW+1．0407(R2=0．91)．该法对16种多环芳烃的检出限为0．1-3．5 ng／L,相对标准偏差(RSD,n=5)为4％-23％．用该法分析海洋环境中的痕量多环芳烃,16种多环芳烃的平均回收率为88.2±20．4％,方法快速、灵敏、简单,适用于快速分析海水和沉积物间隙水样中的痕量多环芳烃．国家高技术研究发展计划(863)(批准号:2003AA635180);; 青岛科技将才计划(批准号:04-3-JJ-1)资助项

Comparison of Recoveries of PAHs Obtained by Ultrasound-assisted Extraction from Wet and Freeze-dried Marine Sediment

以美国环保局(EPA)优先控制的16种多环芳烃(polycyclic aromatic hydrocarbons,PAHs)为研究对象,建立了湿法超声波辅助萃取技术提取沉积物中痕量PAHs的可靠方法,对萃取剂、萃取功率、萃取次数和萃取时间进行了优化。并与传统干法超声辅助萃取进行了比较,湿法超声波辅助萃取的PAHs回收率为57%～125%,而干法超声波辅助萃取PAHs的回收率为48%～113%,对相对分子质量小的PAHs如萘～芴的回收率,湿法明显高于干法。该文建立的湿法超声辅助萃取适用于沉积物和泥土中痕量PAHs的快速测定。An ultrasound-assisted extraction method for the extraction of 16 trace PAHs(USEPA priority pollutant) from wet(i.e.untreated) marine sediment was developed.The effects of solvent type,power of ultrasound,and extraction time were studied and optimized.The developed method was compared with the traditional ultrasound-assisted extraction for freeze-dried sediment.The results showed that recoveries of sixteen PAHs extracted from the wet marine sediment ranged from 57% to 125%,whereas those extracted from the freeze-dried marine sediment ranged from 48% to 113%.The results also indicated that the recoveries of PAHs with smaller relative molecular mass(e.g.naphthalene and fluorine) extracted from the wet sediment were higher than those from the freeze-dried sediment.Thus the developed method was appropriate for rapid determination of trace PAHs in marine sediment and soil.海洋公益性行业科研专项(200705011);; 中国海监技术支撑体系项目;; 2008年海洋环境保护及节能减排专

纳米Co_3O_4的制备及其在富氢气氛下CO选择氧化反应中的催化性能

过渡金属氧化物四氧化三钴(Co3O4)在CO氧化反应中展示了较好的低温活性.Co3O4催化剂用于富氢气氛下CO选择氧化反应已引起了人们极大的关注,具有潜在的应用前景.采用液相沉淀-热解氧化方法制备了2种不同形貌的纳米Co3O4.用X射线衍射(XRD)、扫描电子显微镜(SEM)等技术考察了包括沉淀剂种类、老化时间、焙烧温度等合成条件对生成Co3O4形貌、晶粒尺度的影响.制备的Co3O4的外形与沉淀前驱物外形直接相关.焙烧温度越高,Co3O4的颗粒越大.研究了制得的Co3O4在富氢气氛下CO选择氧化反应中的催化性能.对比以上方法制备的Co3O4的催化性能发现,催化剂的粒径和比表面积与催化剂的活性存在关联.使用尿素沉淀法并经250~300℃空气热解氧化制得的Co3O4具有较好的催化活性

Concentration and distribution of polycyclic aromatic hydrocarbons in surface sediments collected in the Southern Yellow Sea

采用气相色谱与质谱联用(gC/MS)技术,在一个航次内对南黄海表层沉积物中16种优先监控的PAHS的污染状况进行了调查,采用菲/蒽、荧蒽/芘、荧蒽/(荧蒽+芘)、吲哚芘/(吲哚芘+苯并(g,H,I)苝)等特定比值对PAHS来源进行了分析.结果表明,南黄海表层沉积物中检出PAHS的总含量为90.4~732.65ng·g-1,各站点均以4~6环为主;与其它站位相比,倾废区的H01站位受到PAHS污染较为明显,无论是16种PAHS总量还是高分子量组分最高值都出现在该站点,虽然该海区沉积物中PAHS的含量没有超出生物影响低值,但苯并(b)荧蒽、吲哚芘和苯并(g,H,I)芘等一些没有最低安全标准的PAHS也有不同程度的检出,对海洋生物具有潜在的毒副作用.PAHS可能来源于原油、生物和煤燃烧造成的污染.The concentrations of sixteen representative Polycyclic Aromatic Hydrocarbons(PAHs) in surface sediment samples collected from the Southern Yellow Sea were determined by GC-MS.The distribution and potential sources of PAH contamination in the region were investigated.The types of PAHs found in the surface sediments were mainly 4～6 ring PAHs,and they are unevenly distributed among the different sampling sites covering an area of 139 km2.The area is known for continuous waste dumping activities in recent years,and indeed sites adjacent to such activities were found to have high levels of PAHs.Some high molecular weight PAH compounds such as benzo$$b$$fluoranthene,dibenzo$$a,h$$anthracene and benzo$$g,h,i$$perylene were detected in some samples.The health implication of these contaminants needs careful assessment since toxicity guidelines are not available for these species.The potential sources of PAHs are discussed using various source-specific PAH indexes such as Phenathrene/Anthracene、Fluoranthene/Pyrene、Fluoranthene/(Fluoranthene+Pyrene) and Indeno [1,2,3-cd] pyrene/(Indeno[1,2,3-cd] pyrene+Benzo [g,h,i] perylene).The composition of the observed PAHs reflects that they originate from both petroleum utilization and incomplete combustion.海洋公益性行业科研专项(No.200705011);中国海监技术支撑体系项目;2008年海洋环境保护及节能减排专项---

Application of oil spill identification by GCMS——A case study

通过对中国近海海域一个具体海面溢油事例的研究,提出了通过气相色谱及气质联用技术进行海面溢油鉴别的方法。采用GC-FID对油样中的正构烷烃的主要组分进行定性分析,利用GC-MS对油中难降解的生物标记化合物:霍烷及其他五环三萜类化合物、规则甾烷及重排甾烷类化合物、三芳甾类化合物、多环芳烃进行分析,计算相应的比值并采用"t-分布"方法进行溢油样品和可疑溢油源样的相关分析。结果如下:(1)从GC-FID色谱图可以看出,YY2679与KY0631、KY0632的色谱图极其相似,与其余四个可疑油源的色谱图差异较大。六个可疑油源的R值在0.04~1.95之间,只有KY0631和KY0632的R值小于0.1,KY0633~KY0636与YY2679的差异不是由风化引起的,可以排除,由此可以推断出YY2679溢油样品可能来源于KY0631或KY0632两个可疑溢油源。(2)采用21个生物标志物指标进行相关性判别,KY0631可疑溢油源在比值点的区间范围为95%和98%时,有多个点x或y误差棒均未跨过直线y=x。KY0632可疑溢油源在比值点的区间范围为95%时,各点的x或y误差棒均跨过直线y=x,由此推断YY2679溢油样品和可疑油源KY0632是同一油源。On the basis of a case study,a method to identify the spilled oil at sea was introduced.N-alkane distribution patterns of unknown oil were recognized by gas chromatography-mass spectrometry determined the distribution of a suit of petroleum biomarkers hopanes,triterpanes,regular steranes diasteranes,triaromatic steroids and polycyclic aromatic hydrocarbons.The calculated diagnostic ratios for selected biomarker in the source of the spilled oil were done.The correlation studies compared the spill sample and suspected source were made.The results showed three samples nearly identical GC chromatographic profiles,n-alkane distribution patterns,as well as nearly identical diagnostic ratios.This implies that they were most likely from the same source.In 95%confidence limit,all diagnostic ratios of sample KY0632 is exactly the same as for YY2679,so conclusion that the sample of KY2679 and YY0632 are come from the same source