Numerical simulation of deformations and forces of a floating fish cage collar in waves

The dynamic behavior of a fish cage collar in waves was investigated using a numerical model based on the finite element method. The floating collar and mooring system were divided into a series of line segments modeled by straight massless model segments with a node at each end. To verify the validity of the numerical model, research data from other authors were cited and compared with the simulated results, the comparison of results showed a good agreement. The numerical model was then applied to a dynamic simulation of a floating cage collar in waves to analyze its elastic deformation and mooring line tension. The simulated results indicated that the greatest deformation of the collar taken place in the position of the mooring line connection point when incident waves were in the same direction. An increase in the length of mooring line would help to decrease the mooring line tension of the collar. Furthermore, the effects of collar dimension, including collar circumference, pipe diameter in cross-section, and pipe thickness, on the dynamic behavior of the floating collar were discussed. The results of this study provided a better understanding of the dynamic behavior of the fish cage collar.     

泰和乌鸡配套系商品肉鸡的肉质特性研究

研究了泰和乌鸡配套系商品肉鸡的肉质特性。结果表明:通过改良育种后,泰和乌鸡配套系商品肉鸡不仅早期生长速度得到了较大的提高,而且与原种泰和乌鸡的肉质特性基本一致。     

Iron uptake in a bicarbonate-resistant cell line of tobacco

Abstract

In alkaline soils, plant growth is impaired mainly by high pH and high concentration of bicarbonates. The bicarbonate concentration increases the pH value, and causes deficiency of iron. A bicarbonate-resistant cell line (BR line) of tobacco (Nicotiana tabacum L. cv. Burley21) was selected by adding excess bicarbonate ions (20 mmol L^?1) to the culture medium. The pH of the medium was buffered 8.0 to 8.3. Under these conditions, about 80% of iron in the medium became insoluble. However, under such conditions, the BR line grew well. In this report, we examined some characteristics of the growth and iron uptake in the BR line under iron-deficient (i.e. high pH or no-iron) condition. At pH 5.8, the Fe³⁺ reduction activity was not significantly different between the non-selected line and the BR line. At pH 8.0, however, the Fe³⁺ reduction activity of the BR line was higher than that of the non-selected line. In no-iron condition, the growth of the non-selected line was markedly reduced after 2 weeks, while the BR line was not affected. The content of malic acid in both lines increased with the medium pH, and the content in the BR line was higher than that in the non-selected line. The BR line was able to adapt to the conditions, which restricted iron uptake, such as high bicarbonate concentration, high pH, and low iron conditions. The high ability of Fe³⁺ reduction was maintained at even high pH conditions. Further, the BR line may be able to improve the utilization of iron in the cells.     

优质籼型水稻光温敏核不育系万金S的选育

万金S是广东海洋大学农学院利用扬稻6号(9311)的育性变异单株育成的水稻光温敏核不育系,于2009年9月通过广东省技术鉴定。万金S不育期间败育彻底,不育性稳定,不育株率100%,花粉不育度和套袋自交不实率均为99.99%;不育起点温度较低(23～24℃),在湛江不育期135 d以上;开花习性好,异交结实率高达60%以上;米质优,达国标《优质稻谷》2级标准;所配组合杂种优势强,稻米品质优,其中万两优香1号于2011年6月通过了海南省品种审定。     

陆地棉矮化材料株高与纤维品质关系的研究

在一定高度范围内,研究陆地棉矮化材料植株高度与纤维品质之间的相关性。利用陆地棉矮化材料杂交后代(F2),进行植株高度与纤维品质的相关性分析。结果表明,矮化植株高度在一定范围内,株高与纤维长度存在着极显著正相关,随着植株高度的升高,纤维品质逐渐提高,当植株高度达到75 cm以上时,纤维品质可达到优质水平。矮化植株的正常高度应该在75 cm以上,才能确保纤维品质不受植株高度的影响。     

对雾霾问题的会计确认、计量与披露的思考

为应对当前日益严重的环境问题，加大对环境会计的探索与研究，从环境会计视角出发解决当前的雾霾问题是一种有效的方法。结合雾霾的定义理清国内外产生雾霾问题的主要成因，在纵观国内外环境会计研究动态的基础上，借鉴美国环境会计的基本内容，展开雾霾问题的会计确认、计量与披露。雾霾问题的会计确认上主张用“三步走”方法，在计量雾霾问题发生的成本时主要采用恢复费用法、机会成本法以及人力成本法的计量方法，环境会计报告信息披露问题上坚持自愿披露和强制披露相结合的方法，最终为会计信息使用者作出决定提供帮助。     

基于孝感市水禽养殖农户发展前景的分析和研究

文章从对湖北孝感市水禽产业调查入手，结合孝感实地调查报告数据，探讨了孝感市水禽养殖农户发展前景的现状与问题，并提出建议。研究结论对促进相关模式的水禽养殖农户的发展具有一定的借鉴意义。     

线损分析在轨道交通企业能源管理中的应用

轨道交通的不断发展需要更多的电能,但当今能源日趋紧张,对节能降损必须予以足够的重视.所以轨道交通企业须在供电用电管理中加强线损的分析和预测,从供电设计、规划、管理等方面实施降低线损管理,使企业节能降耗并有效提高经济效益.     

农业科研院所因公出国（境）管理研究

以中国热带农业科学院热带作物品种资源研究所（以下简称：热科院品资所）为例子,分析热科院品资所因公出国（境）现状、存在问题并提出了解决对策。