初始场与云微物理参数方案在飑线数值模拟中的对比研究

采用CM1模式以200 m的高精度水平网格距对一次东北冷涡下的飑线过程进行模拟,采用1 km的水平网格距进行对比试验探究网格距的影响,并通过探空资料的替换与修改研究不稳定能量和垂直风切变对飑线发展的影响。研究表明,水平网格距增大主要使系统演变减缓,强度也有一定的减弱;初始场的不稳定能量减小会使飑线减弱明显,直至无法生成;垂直风切变对飑线的形成影响较小,主要改变了飑线的结构,没有垂直风切变时形成的飑线更为松散。最后的敏感性试验研究了7种云微物理参数方案对飑线内水粒子分布的影响,发现不同的云微物理参数方案会使水粒子的含量和分布出现变化,进一步影响固、液态的降水,飑线模拟采用的NA方案高层冰和雪含量最高,但由于雨和降落到地表的雹、霰含量低,使得累计降水量最小。     

Zinc,copper, and strontium isotopic variability in the Baiyangping Cu–Pb–Zn–Ag polymetallic ore field,Lanping Basin,Southwest China

Acta Geochimica - The Baiyangping Cu–Ag polymetallic ore district is located in the northern part of the Lanping-Simao foreland fold belt, between the Jinshajiang-Ailaoshan and Lancangjiang...     

基于深度置信网络的煤层含气量测井解释研究

为了解决煤层含气量定量解释问题,将煤层测井数据与煤心解吸数据作为输入和输出参数,构建深度置信网络(DBN),进而预测煤层含气量。研究以甘肃合水地区测井数据为例,筛选出该地区120组煤层样品作为DBN样本分析数据。选择短源距自然伽马、自然伽马、密度、长源距自然伽马和浅侧向5条测井曲线,作为DBN的输入参数,煤层气含量作为DBN的输出参数,研究RBM数量和隐藏神经元数量对计算结果的影响。并通过概率统计法、BPNN、DBN和SVM计算了30组煤层的煤层气含量,比较不同方法的预测效果。结果表明:①受限玻尔兹曼机(RBM)对DBN计算结果的精度有一定的影响,RBM数量达到7层时,预测结果准确性更高;②选择合适的隐藏层神经元数量,可以保证计算结果的精度和稳定性,神经元数量为20时,预测结果精度更高,稳定性更好;③RBM使得DBN的准确性高于BPNN,此外,DBN的计算准确性和稳定性高于概率统计法和SVM。     

Spectral induced polarization study on enzyme induced carbonate precipitations: influences of size and content on stiffness of a fine sand

Heterogeneity in either chemically or microbiologically induced carbonate-based ground improvement methods is a major obstacle in engineering application. Spectral induced polarization (SIP), an innovative and nondestructive method, which has demonstrated promise in monitoring microbial activity, was used in this study to monitor enzyme induced carbonate precipitation (EICP). The complex conductivities, together with the shear wave velocities (V_s), of an EICP modified sand were monitored using a self-developed spectral induced polarization–bender element column. The mean precipitate size was calculated by relaxation time (τ) and the Schwarz equation. The precipitate contents were calculated by cumulative gamma distribution function on the global polarization magnitude (m_n) with R²?=?0.989. The stiffness of the enhanced geomaterial, in terms of V_s, correlates to m_n with a cumulative lognormal distribution function with R²?=?0.967. Contact cementation was postulated as the dominant association pattern. The possible mechanism for this may be the formation of eddies and the nucleation of CaCO₃ crystals during precipitation. The results suggest that SIP can be used as an effective nondestructive monitoring tool to assess the stiffness of geomaterials.

     

Two bicistronic DNA vaccines against Vibrio anguillarum and the immune effects on flounder Paralichthys olivaceus

Journal of Oceanology and Limnology - Chemokines are cytokines that can promote the activation and migration of immune cells, and increase the recognition of antigen by antigen-presenting cells...     

西太平洋杜氏枪鱿(Uroteuthis duvaucelii)群体形态差异分析

杜氏枪鱿(Uroteuthis duvaucelii)为西太平洋海域广布种,形态特征易受地理阻隔和生态环境等因素影响。采用形态学观察和多元统计分析方法(包括主成分分析、判别分析、聚类分析和单因素方差分析),对采自南通、宁波、南麂岛、东山、汕头、阳江和泰国湾的杜氏枪鱿7个自然群体共202个样品的形态差异进行了比较分析。结果显示:雌、雄群体主成分分析都得到5个主成分,累积贡献率分别为63.395%和67.591%,主成分1和主成分2的散点图均显示各群体存在重叠;雌雄群体的综合判别准确率分别是58.7%和57.3%;雌、雄群体的聚类分析结果基本一致,将7群体分成两支:泰国湾群体与南通、阳江群体聚为一支,宁波、南麂岛、东山和汕头群体聚为一支;所有群体形态测量指标的单因素方差分析结果无显著差异。泰国湾雄性第三腕大吸盘角质环齿数只有7个,与其他群体(11~15个)差异极显著,雌性个体角质环无显著差异。此外,扫描电镜结果显示泰国湾和阳江样品的齿舌形态和大小具显著差异。研究结果为杜氏枪鱿种质资源保护、合理利用与科学管理提供基础资料。     

黏土中桩靴底部吸附力产生机理研究

在海洋工程中,移动钻井平台在作业结束后需要转场时,经常会遇到拔桩困难的问题,桩靴底部的吸附力是上拔力的重要组成部分,明确其产生机理及发展规律对于上拔力计算与缓解上拔困难问题有重要意义。通过室内模型试验研究了黏土中桩靴底部真空度对桩靴吸附力产生机理的影响,试验结果表明,桩靴底部真空度的变化对上拔力的影响显著,而桩靴贯入深度和上拔速率会对真空度产生影响。当真空度达到峰值时,桩靴底部吸附力与上拔力几乎同时达到峰值,因此可以通过减小桩靴底部真空度的措施来减小上拔力。根据试验结果,提出了运用真空吸盘理论来计算桩靴底部吸附力的计算公式。所述吸附力计算方法与试验结果进行对比,其误差较小,对工程实践具有一定的参考意义。     

Effects of supplemental coated or crystalline methionine in low-fishmeal diet on the growth performance and body composition of juvenile cobia Rachycentron canadum （Linnaeus）

We evaluated the effects of supplemental coated and crystalline methionine （Met） on the growth performance and feed utilization of juvenile cobia （Rachycentron canadum Linnaeus） in a 60-d feeding trial. Fish groups were fed one of six isonitrogenous and isolipidic diets： 1） fishmeal control; 2） un- supplemented experimental （low-fish-meal diet deficient in Met）; or 3） one of four Met diets supplemented with crystalline L-Met, cellulose-acetate-phthalate coated L-Met, acrylic-resin coated L-Met, or tripalmitin- polyvinyl alcohol coated L-Met. The test diets were fed to triplicate groups of cobia （initial body weight 5.40-4-0.07 g） twice a day. The weight gain and specific growth rate of the fish fed the RES diet were highest among the Met-supplemented groups and were 23.64% and 7.99%, respectively, higher than those of the fish fed with the un-supplemented experimental diet （P〈0.05）. The protein efficiency ratio of the fish fed the MET diet was significantly higher than that of the fish fed the un-supplemented experimental diet and the fish in the other methionine supplementation groups （P〈0.05）. Our results suggest that supplementation of crystalline Met in low-fish-meal diets promotes the growth performance of juvenile cobia.