The study of s-process nucleosynthesis based on barium stars, CEMP-s and CEMP-r/s stars

In order to get a broader view of the s-process nucleosynthesis we study the abundance distribution of heavy elements of 35 barium stars and 24 CEMP-stars, including nine CEMP-s stars and 15 CEMP-r/s stars. The similar distribution of [Pb/hs] between CEMP-s and CEMP-r/s stars indicate that the s-process material of both CEMP-s and CEMP-r/s stars should have a uniform origin, i.e. mass transfer from their predominant AGB companions. For the CEMP-r/s stars, we found that the r-process should provide similar proportional contributes to the second s-peak and the third s-peak elements, and also be responsible for the higher overabundance of heavy elements than those in CEMP-s stars. Which hints that the r-process origin of CEMP-r/s stars should be closely linked to the main r-process. The fact that some small r values exist for both barium and CEMP-s stars, implies that the single exposure event of the s-process nucleosynthesis should be general in a wide metallicity range of our Galaxy. Based on the relation between C _r and C _s, we suggest that the origin of r-elements for CEMP-r/s stars have more sources. A common scenario is that the formation of the binary system was triggered by only one or a few supernova. In addition, accretion-induced collapse(AIC) or SN 1.5 should be the supplementary scenario, especially for these whose pre-AGB companion with higher mass and smaller orbit radius, which support the higher values of both C _r and C _s.     

The impact of sulfate reduction on the distribution of methylmercury in reservoirs in the city of Guiyang

In this paper, the relationship between sulfate reduction potential and mercury methylation potential was studied in the Aha, Baihua and Hongfeng reservoirs from Guiyang City. The methylmercury (MeHg) concentrations of lake water in the Aha Reservoir were greatly elevated as compared to those of the Hongfeng and Baihua reservoirs, which was correlated with its distinctly high SRB abundance, SO42-, and S2- concentrations. Among the three reservoirs, however, the highest MeHg was observed in in the top several centimenters of pore water profile in the Hongfeng Reservoir where the lowest S2- in pore water occurred. The distributions of MeHg in lake water and pore water showed the highest methylation potential occurred at water-sediment surface for the Aha Reservoir and the in the top several centimenters of sediments for the Hongfeng Reservoir. It is guessed that the highest mercury methylation only occurs at the sites with certain sulfide concentrations.     

A New Conceptual Base for Food and Agricultural Policy: The Emerging Model of Links between Agriculture, Food, Health, Environment and Society

Everywhere in the world, food and agricultural policy is under scrutiny. Questions are being asked about both past and present public policy and strategy. The motives for reassessment are various, including trade wars, health impact, ecological concerns, population, citizens rights. After decades in which policy was centrally concerned with raising productivity and production, using a fairly simple Input-Output Model, the need for a more complex model for food and farming is becoming clear. The success of the dominant Input-Output Model of farming is that it can claim to have kept up with rising population trends and unleashed astonishing efficiencies. Critics point out, however, that these efficiencies have insufficiently accounted for costs to the environment, health and social well-being. A debate about these considerations grew in intensity during the 1990s, but had earlier roots. As a result, a new model of food and agriculture's contribution to health is emerging.     

中国对虾类淋巴组织培养中 细胞异常的病理研究

在对养殖中国对虾和海捕中国对虾的类淋巴 器官进行组织培养时,发现迁出的细胞空泡化、细胞内颗粒较多。培养一周后由养殖中国对 虾类淋巴组织迁出的细胞开始大量脱落,而由海捕中国对虾类淋巴组织培养出的细胞可生长 30d左右。对未经培养的类淋巴组织及培养的类淋巴组织进行透射电镜观察,发现在养殖中 国对虾类淋巴组织的细胞中除了有球形病毒及球状和多面体状病毒包涵体外,在细胞质中还 含有大量类立克次氏体样原核生物,而且每个细胞中的类立克次氏体均由一单层膜包在一起 ;在海捕中国对虾类淋巴组织的细胞中也发现有球形病毒及球状病毒包涵体,另外还在少量 细胞中发现有类立克次氏体样原核生物存在。感染病毒的组织细胞呈现空泡化、核膜肿胀破 裂、核质固缩、高尔基体肿胀、线粒体嵴消失等病理变化。感染有类立克次氏体样原核生物 的细胞不同程度地呈现出细胞器消失、核染色质固缩等病理结构。     

泾县地震台地磁核旋观测干扰排除分析

地磁观测是地震预报中重要的前兆手段之一。识别干扰,排除干扰,对保证观测资料的可靠尤为重要。我们根据泾县地震台地磁核旋观测过程中遇到的问题,利用对比观测方法,对观测数据进行分析,结果表明该仪器工作正常,性能稳定,精度很高;同时指出,在观测过程中应注意的一些问题,并排除了影响泾县地震台地磁观测的干扰源。     

蒙城地震台地磁Z分量日变化特征分析

利用蒙城地震台近20年的地磁Z分量观测资料,对磁静日幅度、磁扰日幅度和磁静日低点时间的年变化与长期变化进行了分析,结果表明,Z分量日变化特征明显。由此总结出Z分量变化的一些基本特征,对识别地磁场异常变化或干扰变化具有一定的参考价值。     

秦直道旅游开发问题探讨

秦直道是古代连接中原地区和北方少数民族地区的一条重要纽带,它是秦帝国传递中央政令和传播中原文化的重要通讯带,也是秦始皇为抵御匈奴、调动兵力和物资的一条战略要道,在历史上起到了极其重要的作用.通过对秦直道及其现阶段旅游资源开发现状的介绍和在对秦直道旅游资源开发的可行性综合评价与分析的基础上,提出秦直道旅游资源开发的初步构想.     

贵州省罗甸透闪石矿床地质特征及找矿预测

罗甸透闪石矿床属燕山期岩浆热液矿床,成矿作用为接触交代;侵入岩体为辉绿岩,属偏碱性基性幔源浅成岩,岩体呈似层状顺层侵入于二叠系中统栖霞组（P2q）与茅口组（P2m）接触面之间;围岩蚀变有透闪石化和大理岩化,由岩体向外依次分为大理岩化带→透闪石化带;软玉矿体赋存于外接触带茅口组一侧,顺层产出;含矿带厚10～30余米,其中夹矿体十余层,矿体形态以似层状为主,次为透镜状,厚0.05～0.3 m。在1000 km2范围内发现5个辉绿岩体露头,呈带状出露,长3～35 km,显示有矿化,具有较好的找矿远景。     

微压流化式复合生物反应器的同步脱氮

通过对曝气系统的调节,微压流化式复合生物反应器（MP-FHBR）内可以实现好氧区和缺氧区共存,利用这一特点和MP-FHBR中同时存在的活性污泥﹑悬浮生物膜复合生物体系,进行了同步脱氮的试验研究。结果表明,MP-FHBR在好氧-缺氧条件下,实现了同步脱氮过程,TN和COD的平均去除率分别达到77.5%和98.3%。降低DO质量浓度使反应器内形成完全缺氧环境,对MP-FHBR同步脱氮效果没有显著影响,但会降低系统去除COD的效果;而提高DO质量浓度使反应器内形成完全好氧环境,MP-FHBR同步脱氮效果显著下降。在一定范围内提高进水COD/TN有利于提高MP-FHBR同步脱氮效果,COD/TN 由2升高到10,TN平均去除率由58.4%提高到78.8%,而继续提高COD/TN对系统同步脱氮效果的影响并不明显。在反应器允许的条件下,提高污泥质量浓度(MLSS)有利于提高系统反硝化脱氮效果,TN去除率随MLSS的增加而提高。     

叠前时间偏移方法在煤田勘探中的应用

根据克希霍夫积分法的原理,介绍了叠前时间偏移的方法特点,实现过程,以及对地震资料的要求,依托国家重大产业技术专项“西部煤炭资源高精度三维地震勘探”工程,对“青海省鱼卡煤田四井田高精度三维地震勘探”资料进行叠前时间偏移,结果表明其能较好地解决成像质量差、能量聚焦不明显、绕射波收敛不理想等方面的难题。通过与叠后时间偏移对比,对于大倾角地层、断块小且多的破碎带、陡倾角不对称向斜等地质问题,其叠前时间偏移剖面成像质量都有明显的提高,反映的构造关系更加清晰,同相轴连续性增强。总结该方法在多个矿区的推广经验．认为合理的观测系统、较高的资料信噪比,准确的测量资料及较高的中表层速度调查精度是做好叠前时间偏移的前提。