流化冰对于鲣鱼的保鲜效果研究

以远洋鲣鱼为研究对象,以传统淡水碎冰保鲜为对照,研究流化冰处理对鲣鱼的理化性质及微生物特性的影响。结果表明:(1)–4°C冷藏18d后,流化冰保鲜鱼肉pH值、TVB-N、TBA、a*值和菌落总数依次为5.57、10.2mgN/100g、2.87mg/100g、8.92和2.61lgCFU/g,而淡水碎冰保鲜鱼肉各指标已达6.05、20.3mgN/100g、6.60mg/100g、7.16和3.02lgCFU/g,故可知流化冰保鲜处理效果明显优于碎冰保鲜。(2)在25±1°C室温条件下,将冰与鱼放入保温箱内保鲜8h后,流化冰保鲜鱼肉的a*值、pH值、TVB-N、TBA、菌落总数和汁液流失率均显著低于空白和淡水碎冰保鲜处理组(P0.05)。流化冰保鲜可显著减缓鱼体的腐败进程、延长产品货架期,进而满足冰鲜水产品的远洋及长距离运输要求。     

单体分子放射性碳同位素分析在海洋科学及环境科学研究中的应用

单体分子放射性碳同位素分析(CSRA)是近十几年来发展起来的一项新兴的分析手段,将所需的单体分子(生物标志物)从复杂的环境样品基质中分离并富集,再进行加速质谱仪(AMS)的放射性碳(14C)测定。这种分子水平的放射性碳同位素测定技术能够揭示出总有机质同位素组成的异质性,为解释有机碳的来源、迁移和转化等提供了新型的手段。在海洋科学研究中,单体分子放射性碳同位素分析已应用于计算碳在全球各储库的逗留时间并揭示和定量估算化石源有机碳的输入、指示沉积物的搬运过程、示踪微生物的代谢途径、改进沉积物年代学等;在环境科学研究中,单体分子放射性碳同位素分析可用于有毒物质(如多环芳烃)的源解析,示踪有机污染环境中微生物的代谢途径等。伴随着单体分子分离技术的改进及AMS灵敏度的提高,CSRA技术的应用会更加广泛。     

鳗鲡目鱼类线粒体蛋白质编码基因易位及系统演化关系分析

鳗鲡目鱼类线粒体基因组的基因组成较为保守,在58个线粒体基因组中,仅有3个物种存在基因数量的差异。在19个鳗鲡目鱼类线粒体基因组中存在主编码基因的重排。主编码基因的变异位点分析结果支持nad5、nad4和nad2基因作为cox1和lrRNA基因辅助的分子标记。鳗鲡科Anguillidae的20个种(亚种)聚在一起,强烈支持鳗鲡科为单系群(BPP=100)。鳗鲡科下属的3个类群(大洋洲类群、大西洋类群和印度洋-太平洋类群)也同时得到有力的验证(BPP均为100)。线鳗科Nemichthyidae和锯齿鳗科Serrivomeridae亲缘关系最近,二者聚类后,与鳗鲡科Anguillidae构成姊妹群(BPP=100)。在囊喉鱼亚目Saccopharyngoidei中,宽咽鱼科Eurypharyngidae与囊鳃鳗科Saccopharyngidae聚类(BPP=100),同时,单颌鳗科Monognathidae与月尾鳗科Cyematidae聚类(BPP=100),4个科聚在一支,支持囊喉鱼亚目为单系群(BPP=100)。在囊喉鱼亚目线粒体基因组中,3个物种(吞鳗Eurypharynx pelecanoides、拉文囊鳃鳗Saccopharynx lavenbergi和杰氏单颌鳗Monognathus jesperseni)存在主编码基因的重排。16种鳗鲡(细美体鳗Ariosoma shiroanago、短吻颈鳗Derichthys serpentinus、凯氏短尾康吉鳗Coloconger cadenati、鸭颈鳗Nessorhamphus ingolfianus、龟草鳗Thalassenchelys sp.、粗犁齿海鳗Cynoponticus ferox、百吉海鳗Muraenesox bagio、巨斑花蛇鳗Myrichthys maculosus、大吻沙蛇鳗Ophisurus macrorhynchos、几内亚副康吉鳗Paraconger notialis、哈氏异康吉鳗Heteroconger hassi、小头鸭嘴鳗Nettastoma parviceps、弱头鳗Leptocephalus sp.、斑点长犁齿鳗Hoplunnis punctata、尖吻小鸭嘴鳗Facciolella oxyrhyncha和星康吉鳗Conger myriaster),与鳗鲡目线粒体主编码基因的原始排列相比,共享nad6基因的易位。同时,基于线粒体基因组13个蛋白质编码基因构建的系统演化树,强烈支持这16个物种聚为一支(BPP=100)。然而,由此而带来的海鳗科Muraenesocidae、拟鯙科Chlopsidae和糯鳗科Congridae是否为单系群的问题,值得今后深入探究。     

基于GPS反射信号技术的渤海海冰实验

传统的海冰检测手段都存在着受天气影响或实时检测成本太高的缺点,为了更实时有效的检测海冰,减轻海冰灾害对于我国的影响,并达到防灾减灾的目的,本文研究了GPS反射信号(GPS-R)技术检测海冰的可能性。通过对2013年2月下旬在中国天津渤海湾的岸基架设GPS信号接收机所接收的观测数据进行分析,使用不同特性的反射海域(几乎全为海水或是海冰)的数据进行比对分析,其结果显示极化比值(反射左旋信号与直射右旋信号的比值)能够明显反演海冰密集度。本文首次将GPS-R技术应用于国内自主设计的渤海海冰检测实验中。     

电站坝基岩体评价及深层抗滑稳定性分析

某水电站位于雅鲁藏布江中游桑日至加查峡谷段出口处,坝型为混凝土重力坝,最大坝高116m,属高坝。混凝土重力坝主要是依靠坝体自身重量于基础之上产生的摩擦力及坝体与基础之间的凝聚力来抵抗水压力以满足稳定要求,对基础岩体要求较高。根据该水电站坝基工程实践,从坝基岩体质量评价方法、分级标准及深层抗滑稳定计算方法等方面进行一些有益探索,对类似工程坝基岩体质量评价及深层抗滑稳定计算具有指导意义。     

大汶口盆地漕河崖矿段岩盐矿地质特征及岩相分布规律

通过对漕河崖矿段进行勘探工作,发现该区岩盐矿层赋存较多,矿层厚度在0．40～14．72 m,NaCl 平均品位86．39％,属厚度较稳定,品位均匀矿层;岩盐矿层不仅局限在 F2,F3,F43个断层的切割范围内,在 F3断层北部尚有岩盐层赋存。     

Controlling Factors,Accumulation Model and Target Zone Prediction of the Coal‐bed Methane in the Huanghebei Coalfield,North China

The Huanghebei Coalfield, one of the coal production bases in North China, was considered as a coalfield without coal‐bed methane (CBM) during past decades. In recent years, however, CBM has been discovered in coal‐bearing successions. In order to understand the CBM geological characteristics and accumulation process in this area, fifteen coal samples were collected and analyzed with respect to coal maceral and reflectance. The result shows that the gas distribution is uneven and the content varies in different areas even for the same coal bed. The storage of CBM is affected by geological factors such as burial depth, geological structures, and magmatic intrusion, among which the former two are more important in the formation of CBM. Deep burial of coal beds with the presence of cap‐rock mudstone can seal CBM. The CBM is also accumulated and preserved at the place where normal faults are distributed. Magmatic intrusion causes contact metamorphism and controls the CBM formation by heating the coal‐bearing successions. The obtained data indicate the geological conditions in northeastern Zhaoguan Mine are preferable for CBM formation and conservation; recent exploration estimates the CBM geological reserves up to 282.16 Mm³ and average of reserve abundance at 0.1662 × 10⁸ m³ km^?2. The Changqing Mine is a potential prospect in terms of CBM exploration since its geological conditions (structures and burial depth) are similar to the Zhaoguan Mine and its cap rock is even better.     

Suitability evaluation of rural residential areas under the threat of geological disasters:A case study in Yinchanggou watershed of Pengzhou City

At present, the research on the layout of rural residential areas in the mountainous environment under the threat of earthquake disasters and frequent geological disasters is still rare. Taking Yinchanggou watershed in Longmenshan Town of Pengzhou City as an example, based on the summary of the geological hazard development characteristics in this area, the authors carried out the hazard risk zoning through 8 indexes. Then the geological hazard risk zoning was used as the primary factor to evaluate the suitability of rural residential areas. Besides, combined with the topographical conditions, socio-economic situation and ecological environment, a suitable evaluation index system for rural residential land under the threat of geological disasters was constructed, with the restrictive conditions of extremely high-risk areas, single geological hazards, slopes ≥25° and basic farmland protection areas. Finally, the fuzzy comprehensive evaluation method was used to evaluate the suitability of residential land in Yinchanggou watershed of Pengzhou City. The results show that high suitability areas account for 4.2% of the total area of the study area, moderate suitability areas 11.4%, low suitability areas 10.5%, and unsuitable areas 73.8%. The “suitable” areas for rural residential land are mainly distributed along the highway, and some are multiple “blocky” concentrated distribution areas. The terrain is flat and the traffic condition is convenient, which can provide some guidance for the selection of new rural residential locations.