甜菜维管束的发育及其在各器官间贯通的研究

本试验以糖用甜菜和饲用甜菜为材料，研究了甜菜体内维管束的发育及其在各器官间的贯通方式，结果表明：（１）甜菜体内维管束的发育始于子叶节，并由此向上和向下分别形成叶柄和根中的初生维管束；三生维管来是由额外形成层产生，它的发育始于下胚轴的上半部，即子叶节的下方。（２）１～７个三生维管束环及其环间薄壁组织是根体的主要组成部分，而这些三生维管束环的维管束直接与基本叶中的维管束相贯通，这时甜菜根的膨大、叶片中糖分向根部运输与积累有重大意义。     

桩网连接方式对桩柱式围网网衣受力的影响

海洋围网养殖是一种新型且具有应用前景的生态养殖模式,主体由桩柱、网衣、纲绳等结构组成。网衣系统安全是决定围网养殖工程安全的关键所在。本研究主要采用集中质量点法建立围网网衣数值模型,利用StokesⅢ阶波波浪理论,研究波浪载荷作用下,桩网连接方式(桩网直接连接和桩网间接连接)对网衣最大偏移量、网线和纲绳最大受力、系缚点受力的影响。研究结果显示,网衣的形变呈不对称分布,在波高小于4 m时,2种连接方式的围网网衣最大偏移量几乎保持一致,当波高大于4 m时,2种连接方式的网衣波峰处位移最大,且波谷处偏移逐渐减小,总体上看桩网间接连接的桩柱式围网偏移量更大;2种连接方式的纲绳和网线受力随波高增加而增大;相同波高条件下,纲绳和网线的最大受力部位均在竖纲连接槽钢处,桩网间接连接方式的围网纲绳和网线受力要小于桩网直接连接的方式;系缚点的最大受力在水平面下0~1 m内,间接连接方式的系缚点最大受力小于直接连接方式。水平网线的受力随着波高的增加而增加,间接连接方式的网线受力要小于直接连接的方式。研究结果可为桩柱式围网网衣系统连接方式的选择与安全评估提供参考。     

Comparison and Analysis of Reliability Between 3/2 Connection and 4/3 Connection of Station

The main electrical scheme of a station is principal part of power system electrical connection,and its structure not only determines whether customers can acquire enough electric energy,but also influence economical efficiency of construction and reconstruction of a station.3/2 Connection and 4/3 Connection have been widely used in large scaled station.Three groups of alternative designs are chose in the article,of which the first group is single unit connection,and the other two are combined unit connection,and in each group there are one 3/2 Connection and 4/3 Connection plan.A reliability analysis system of main electrical scheme has been applied,to compare and analyze the reliability and economical efficiency of these two kinds of connection comprehensively.The result involves adequacy,security,economical efficiency indices and sensitivity analysis of component dependability parameter of each design.The result shows both 3/2 Connection and 4/3 Connection has its own relative merits,but 3/2 Connection has well applicability: Failure rate of generation has most obvious influence on reliability of the main electrical scheme.And quantified calculation of reliability is necessary in planning and choice of main electrical scheme of station.     

冷水滩区土地利用与区域经济关联度研究

区域土地利用是一个复杂的人地关系系统,土地利用的合理与否直接关系到区域社会经济发展的可持续性。因此,进行土地利用与区域经济关联度研究,对促进冷水滩区的区域发展战略和政策的有效实施,实现区域土地利用与经济协调发展具有重要意义。     

同异分析的联系势测验及其在小麦品种区域试验中的应用

运用联系数学理论，提出了同异分析的联系势概念；定义了联系均势、联系同势和联系异势；规定了联系势的差异显著性原则，并将联系势划分为9个等级，在此基础上，形成了联系势测验方法，并结合实例介绍了其在小麦品种区域试验中的具体应用。检验结果表明，这种方法具有较好的应用前景。     

江苏如东文蛤大面积死亡原因探究

2002年10月江苏省如东洋口文蛤大面积死亡。作者对现场采集的死烂文蛤、近岸海水、滩涂底质3类样品进行检测，并与苴镇、东凌、吕四样品对比分析。发现：(1)洋口死烂文蛤体内有害重金属Cr、Pb、Zn、Cd、As含量比另3处高出数十倍；(2)事发时洋口近岸海水水质与其他水域比较，Zn偏高20倍以上，Cr偏高10倍以上，As亦偏高；(3)洋口滩涂底质中有害重金属含量已接近污染上限。     

慢行系统导向下的广州城市公园连通策略

慢行系统作为彰显城市魅力和提升人居环境的重要基础,在广州打造“国际花园城市”的进程中发挥着重要作用。以慢行系统为导向,针对广州市中心城区城市公园连通性存在的山水文脉联系薄弱、慢行路径不连续、服务品质不佳的问题,基于国内外对慢行系统和公园连通性的研究,及广州慢行相关规划实践,提出3个城市公园连通策略:在构建连通网络上,从景观山水、断点空间、居民生活方向入手,重塑慢行网络;在具体空间营造上,分区分径,构建互为关联的主题环路;在实施连通的路径上,从特色策略、植物配植、意境营造等方向入手,打造品质化慢行空间。     

Connection to nature and time spent in gardens predicts social cohesion

A person’s health and wellbeing are contingent on the amount of social support that they receive. Similarly, experiencing nature has been shown to improve people’s health and wellbeing. However, we do not know how relationships between social cohesion, nature experiences and nature connection could interrelate and vary across different types of urban green spaces, and in non-Westernised cultures. We conducted a study on 1249 residents in Singapore, a tropical city-state, and measured three dimensions of social cohesion (i.e. general social cohesion; trust and sense of community; and social interactions), various types of nature experiences (i.e. amount of green space around one’s residence; frequency and duration of urban green space visits; frequency and duration of visits to gardens), and three dimensions of one’s connection to nature: self-identity with nature, desire to experience nature, and environmental concern (using the nature relatedness scale). We found that people who strongly identify with nature, who enjoy being in nature, and who had more frequent gardens visits were more likely to have a stronger sense of social cohesion across two dimensions. However, those with stronger environmental concern reported an overall weaker sense of social cohesion, possibly due to the perception that society’s contributions to conserve environmental problems was insufficient. Further, people who gardened more frequently were also more likely to visit green spaces, self-identify with nature and exhibit a stronger desire to experience nature. We propose that strategies targeted at encouraging people to engage in nature-related, collaborative activities at the local community level, such as spending time in local gardens, will increase urban residents’ daily nature experiences and its associated benefits such as improving social cohesion.     

Relationships between nature connectedness,biodiversity of private gardens,and mental well-being during the Covid-19 lockdown

Private gardens have an enormous impact on urban biodiversity, making individual householder behavior critical to the conservation and enhancement of biodiversity in urban areas. Nature connectedness is considered to be a prerequisite for proenvironmental behavior, but how it manifests in private gardens is largely unexplored. Nature connectedness has also been found to be associated with several well-being dimensions. The present study investigates the associations between nature connectedness, biodiversity of private gardens, and mental well-being during the Covid-19 lockdown, a stressful period in many people’s lives. Hierarchical regression analyses were used to analyze data from an online survey of private gardeners in two cities, one in Germany and one in New Zealand, in May 2020, approximately two months after the beginning of the first Covid-19 lockdown. Garden characteristics explained a significant amount of variance in depression symptoms during the Covid- 19 lockdown. In light of rising pressures on urban green spaces, the findings point to the importance of private garden qualities for mental health and well-being. Nature connectedness emerged as a significant predictor of feature richness, a measure of the heterogeneity of habitats that support wildlife, and plant growth form richness in people’s gardens in both city samples. Nature connectedness was also a significant predictor of the extent to which people experienced positive emotions during the Covid-19 lockdown but not negative emotions and depression symptoms. Our results suggest that nature connectedness can provide benefits for both the environment and people through its positive association with private garden biodiversity and positive emotions.