基于顶点度的多分辨率表示

针对边收缩算法在计算大曲率面距离公差时计算量大 ,且收缩大曲率面所含的线段时易使关键点发生偏移而引起模型变动过大、简化不够准确的问题 ,本文在边收缩算法基础上提出了加入顶点度控制的算法 ,以减少大曲率面距离公差的冗余计算 ,并提高模型简化质量。实验表明该算法能提高模型简化质量 ,并加快图形收缩的生成速度。     

中华鲟配合饲料适宜蛋白质含量及最佳蛋白能量比研究

以酪蛋白和明胶为蛋白源 ,添加豆油、鱼油、糊精、纤维素以及适量的维生素和矿物质混合剂配制试验饲料 ,饲料配成5个蛋白质水平 ,每个蛋白水平分别包括5个能量级 ,以体质量增长倍数、蛋白质效率和饲料系数为评判依据 ,对体质量为8.73g±0.79g的中华鲟(Acipensersinensis)的适宜蛋白质含量及其蛋白能量比进行了研究。经过为期8周的试验 ,结果表明 :中华鲟幼鲟配合饲料中的适宜蛋白质含量范围为35.7%～41.8% ,饲料的最佳蛋白能量比范围为21.85～30.05ng/J。当试验饲料蛋白质含量为40.3% ,蛋白能量比为27.85ng/J时 ,试验鲟鱼获得最大体质量增长倍数为11.60±1.20,最低的饲料系数为1.68±0.23,以及最高的蛋白质效率为1.58%±0.14%。     

Several significant hydrographic characteristics and their formation mechanism in the South China Sea during the spring and summer of 1998

INTRODUCTIONTheSCSisthelargestmarginseainthewestoftheNorthPacificOcean .Theprevailingwindinwinterisnortheast,whileinsummeritissouthwest .Itisstilluncertainthathowthecirculationandtemperature -salinityfieldassociatewiththemonsoonforcingandaccompanywithseveralkindsofvariationsbeforeorafterthesummermonsoonburst .DuringSECMEXin 1 998,twointensiveobservationperiods (IOP)havebeencarriedoutntheSCS (Fig 1 ) :IOP1 ,from 1 0Aprilto 5May ;IOP2 ,from 1 2JunetoJuly 6 ,inordertounderstandthe…     

海湾扇贝养殖群体遗传多样性的研究

用等位基因酶的聚丙烯酰胺凝胶电泳技术,研究了大连沿岸不同生态环境条件下的大李家湾低排筏、大李家湾高排筏、凌水桥、棋盘磨4个海湾扇贝养殖群体的遗传多样性.在4个群体的7种等位基因酶和闭壳肌蛋白中均检测到了22个基因位点,各群体的多态位点比例分别为22.73%,22.73%,22.73%,18.18%(P≤0.95)和27.27%,27.27%,31.82%,36.36%(P≤0.99);杂合度观测值分别为0.064,0.071,0.075,0.069;Hardy-Weinberg平衡偏离指数分别为-0.068,-0.020,-0.032,-0.050;近交系数分别为0.568,0.565,0.487,0.550;位点等位基因有效数分别为1.102,1.109,1.143,1.122;遗传变异综合评价指数分别为0.0060,0.0071,0.0088,0.0073.海湾扇贝养殖群体遗传多样性总体水平较低,但在这4个群体中,凌水桥群体的遗传多样性水平最高,大李家湾高排筏和棋盘磨群体的遗传多样性水平较高,大李家湾低排筏群体遗传多样性水平最低.     

迟缓爱德华氏菌及其致病机理

迟缓爱德华氏菌(Edwardsiella tarda)是一种革兰氏阴性肠道病原菌,感染宿主范围广。在水产养殖生物中,该菌是鱼类(鳗、鲇、鲆等)、两栖类(蛙)、爬行类(鳖、鳄鱼)的重要致病菌。爱德华氏菌病(Edwardsiellosis)是水产养殖中最常见的传染病之一,影响了养殖生物的健康并对水产养殖业危害巨大。随着对迟缓爱德华氏菌致病性研究的深入,对该病原致病因子相关研究取得了一些进展。研究发现一些胞外酶和毒素与细菌的致病过程有关,相关的致病因子有溶血素、软骨素醇、皮下坏死毒素、过氧化氢酶等。这些致病因子参与了细菌的黏附、定殖、侵袭和在宿主体内的繁殖和扩散过程。但从总体而言,对迟缓爱德华氏菌致病因子组成及其致病机制尚缺乏系统深入的研究。最近的研究发现了一种新的致病因子——Ⅲ型分泌系统;迟缓爱德华氏菌的Ⅲ型分泌系统仅存在于致病菌株.而在非致病株中没有发现,与细菌的致病性密切相关,它的出现为人们对迟缓爱德华氏菌的致病性的了解提供了新的视角。     

Bulk particulate organic carbon in the East China Sea: Tidal influence and bottom transport

Five oceanographic surveys were carried out in the East China Sea (ECS) and Yellow Sea from 1999 to 2003. In all, seven different sections were surveyed, but one section (the PN section) was observed on every cruise. Two time-series stations were also surveyed, one located at the Changjiang River mouth, the other over the continental shelf in the PN section.We identified biogeochemical characteristics for waters close to the Changjiang Estuary and in the Kuroshio waters (KW), respectively. Resuspension is a strong feature near bottom over the ECS continental shelf, with suspended matter values 13 times higher than that for the surface. A model of particulate organic carbon (POC) dynamics based on a rectangle equation reveals that POC concentration close to the Changjiang Estuary varies with a semidiurnal period of ∼13 h, coinciding with the tidal period. The upper limit for POC residence times in the seasons we covered over the shelf are estimated to be on the order of weeks and generally increase seaward from near the Changjiang Estuary to the KW. Short POC residence times suggest that POC in the ECS is rapidly exported from euphotic waters.A nepheloid layer, observed as elevated suspended matter in near the bottom of the water column, is important in particle transfer over the shelf, especially in winter when the residual current flows mainly eastward. Cross-shelf transport of POC via the nepheloid layer is estimated to be 0.22 × 10¹² g yr⁻¹. Comparison with other work indicates that POC transport is ∼2% of the Changjiang POC input.     

海水中金属设施防腐、防海洋生物污损及检测技术研究

随着工业的高速发展和人口的急剧増加及环境污染的加剧，淡水资源危机已引起世界各国的普遍关注。据统计，城市用水中工业用水通常占80%左右，而工业用水中有80%是工业冷却用水，所以开发利用海水代替淡水直接作冷却用水是节约淡水的重要途径。海水直流冷却系统具有深海取水温度低且恒定、冷却效果好和系统管理简单等优点，但必须具备以下条件:(1)管道系统防除生物附着污损；(2)管道系统的防结垢；(3)金属腐蚀与防护。多年来有关方面虽然相应地采取了许多措施，但由于主设备通常需常年连续运行，因而往往出现在某段时间、某些部位上效果降低与失效。现行的对海水环境中生物附着腐蚀检测主要采取取样离位分析方法，其结果与实际状态有差异，且生过程中许多重要部位，如海上平台、浮码头、船舶、海滨电厂、化工厂的海水冷却系统和海水管路的管道内、及死角区都很难取样，必要时只有定期停机检查(侯保荣1998； Efird，1976；吉井彻，1967)，造成很大的经济损失。 防止海水环境中的金属设施遭受海水腐蚀和海洋生物污损的方法很多，通常采用阴极保护、防污涂料、电解海水或电解重金属等方法，但这些方法的缺点是：(1)阴极保护能防止金属腐蚀而不能防止海洋生物附着；(2)防污涂料涂刷一次，只能用3-5年，对许多一次性埋入水中的管件无法进行二次补涂，防污涂料所释放出的毒物将长期污染环境；(3)利用电解海水或电解重金属所产生的次氯酸钠或重金属离子来进行防污，即电解防污效果明显，但对金属防腐的作用不大(侯保荣，1999;陈光章，1994;马土德，1996)。总结前人的经验，经过多年的研究，我们利用电化学方法研制出既能防止金属海水腐蚀又能防生物附着的双防与检测新技术系统装置，已通过实海实验，取得了良好的效果。     

A Preliminary Study of Shear Wave in Seafloor Surface Sediments

This article preliminarily reports and analyses the transmission characteristics and behaviors of shear wave in the offshore seafloor surface sediments in China, discusses the relationships between the physical and mechanical features of the shear wave and the compression wave, and compares the testing results with that of Hamilton and Chen et al. The result shows that the shear wave can be tested if the seafloor surface sediment has tangent modulus. The shear wave velocity ranges from 50-600 m/s and the measuring frequency from 50-200 kHz. The sound velocity rate of shear wave and compression wave can be used to appraise the stress-strain feature of seafloor surface sediments. This study provides a basis for further describing and appraising the seafloor sedimentary acoustic-mechanical feature and building a geological-acoustic model on China's offshore sea area.     

几株原甲藻核糖体大亚基RNA基因的部分克隆及序列分析

对7株赤潮原甲藻28S rDNA 5'端部分序列进行扩增、克隆和序列测定,并从GeneBank上获取14个原甲藻28S rDNA序列,用NJ法和ME法构建了原甲藻属的系统树,并对序列进行分析.结果表明,7株原甲藻28S rDNA扩增序列长度为950~958 bp,通过NJ法和ME法构建的系统树完全一致.大部分分离自不同海域的同种原甲藻的序列高度保守,而不同种间在序列高变区却有较大的差异.但来自南海海域的海洋原甲藻(Prorocentrum micans)与分离自其他海域的株系序列差异较大,甚至超出了有些种间的差异.由28S rDNA高变区获得的序列,有望成为浮游植物特异性分子探针设计的良好靶区域.     

An Application of Direct Ritz Method for Random Seismic Responses of Jacket Platforms

1 .IntroductionNowadays tremendous efforts have been devotedtothe analysis of randomseismic responses .Forexample ,American PetroleumInstitute (API) has declared that the analysis of randomseismic re-sponsesis a useful tool for safety inspection. Owing to the complexity of platformand randomness ofload,it is difficult to carry out the randomresponse analysis of a jacket platform. The conventionalrandomvibration methods ,such as square root of the sumof squares (SRSS) and complete quadratic…