国产人造板宽带砂光机功率谱密度和试验模态分析

以国产B229型四四砂架人造板双面宽带砂光机为研究对象,从易产生横纹缺陷入手,对其砂架部件、整机等分别采用试验模态分析(EMA)及功率谱密度法(PSD)来开展振动动态特性研究。在模态试验中,采取测量点固定、改变激振点的跑点测量方法,得到固定测量点对各激振点频响函数,并应用SISO频响函数识别法,通过频响函数曲线拟合来完成模态参数识别,获到典型的整机、砂架部件的频响函数图和接触辊的二阶振型图。通过PSD分析,获得砂光机的PSD图谱和激励频率等。     

Ecophysiological and genetic variation in seedling traits and in first-year field performance of eight <Emphasis Type="Italic">Acacia senegal</Emphasis> provenances in the Blue Nile,Sudan

The genetic variation in seed weight, seed number per kg and seedling traits was compared among eight Acacia senegal provenances originating from the clay plain (east) and sand plains (west) of the gum belt in Sudan. The main objective of this study was to identify germplasm sources of A. senegal that have a good seed germination capacity and seedling traits suitable for reforestation in the clay-soil part of the dryland gum belt in the Blue Nile region in Sudan. A specific objective was to tentatively explore the adaptive strategy of A. senegal populations. Seventeen-week-old seedlings were planted in the field at spacing of 3 m × 3 m, giving 100 trees per plot and replication; within a randomized complete block design with four replications. The experimental site was in the clay plain region. Seed variables showed significant differences. Clay plain provenances showed considerable variation in seed weight and seed number. They had the smallest seed weight but the highest seed number, while the sand (western) provenances had the largest seed weight but lowest seed number. Seedling branch number, root length, root to shoot ratio and shoot dry weight differed significantly among the provenances 12 weeks after germination. Clay provenances had the highest branch number and shoot dry weight but the shortest roots and lowest root to shoot ratio. This was interpreted as showing better adaptation to the site in these local provenances in comparison to those originating from the western sandy soil regions. High positive correlations were observed between seedling variables, such as root nodule and branch numbers; this could be used for early selection. The variation was greater between provenance groups than within them, suggesting that especially selection among groups would yield genetic gain.     

Photosynthetic physio-response of Taxodium ascendens seedlings to different soil water gradients

Four different kinds of water treatments were applied to study the photosynthetic eco-physiological characteristics of Taxodium ascendens seedlings in the environment of the Three Gorges hydro-fluctuation belt. The four kinds of water treatments were: normal growth water condition (CK), light drought stress (T1), soil water saturation (T2), and soil submersion (T3). The results showed that different water treatments could effectively influence the content of the photosynthetic pigment, leaf gas exchange and apparent resources use efficiency of T. ascendens seedlings. It was also demonstrated that the T. ascendens seedlings could not only tolerate water submersion and wet conditions but also endure a certain degree of drought. To establish a protection forest system in the hydro-fluctuation belt in the Three Gorges Reservoir Area, the species T. ascendens is suitable for planting in conditions of root submersion or water-saturated soil. In case it is planted in drought conditions, this tree species should be watered appropriately in order to keep its normal net photosynthetic rate. Translated from Forest Research, 2006, 19(1): 54–60 [译自: 林业科学研究]     

论继续推进沿海防护林体系工程建设的必要性

全国沿海防护林体系二期工程建设规划将于2015年完成,通过二期规划建设,工程取得了巨大成就,但依然存在较大增长空间和发展潜力,为了贯彻落实生态文明建设总体要求,进一步推动沿海防护林持续快速发展,充分发挥其生态、经济和社会效益,从八个方面对继续推进沿海防护林体系工程建设的必要性进行了论述,以期引起各级政府部门的高度重视和全社会关注,并尽早出台沿海防护林体系工程后期有关建设规划。     

生态景观林带在城乡宜居建设中的作用

面对伴随着城市现代化进程所带来的环境问题,宜居城乡建设是改善居住环境问题的重要举措;生态景观林带是以改善破碎化的森林斑块和绿化带、以增强森林为主体的自然生态空间的连通性、以观赏性为目的和以点、线、面相结合的景观廊道网络。生态景观林带在城乡宜居建设中发挥着改善自然环境与人文环境的双重作用,促进了城市与乡村的耦合,是城乡宜居建设的有效途径。     

防火林带营造木荷火力楠混交林生长效果分析

对马尾松低产林改造,营造防火林带木荷火力楠生长效果进行了调查,发现林木生长良好。结果显示：经过14a的培育,其林木生长不同,木荷火力楠混交林的林分生长量,比木荷、火力楠纯林的林分生长量更具优势,平均树高、胸径、树冠、枝下高、郁闭度、单株材积、蓄积量,分别比木荷、火力楠纯林林分平均树高大13.54%、8.55%,胸径粗18.39%、14.21%,树冠大8.24%、22.26%,枝下高8.75%、17.67%,郁闭度大2.13%、3.23%,单株材积大45.43%、41.18%,蓄积量大54.95%、37.54%。土壤肥力N、P、K分别提高0.9%、1.92%、1.79%,1.80%、6.00%、3.64%。木荷火力楠混交林能涵养水源、保持水土,有效控制林火蔓延,可减少森林火灾和灾后损失。     

浅谈牛栏江河道绿化的途径及措施

指出了当前牛栏江水污染严重,牛栏江生态廊道绿化的任务是提高河流“自净”能力,净化水质。探讨了绿化技术途径,包括对河岸带进行区划,确定各带（区）的功能,根据各带（区）特点,布置植物,强调在有限的空间内,千方百计地增加湿生与水生植物种植面积,利用水生植物净化水体,从而实现规划目标。     

Effects of preadoption counseling on the prevention of separation anxiety in newly adopted shelter dogs

Separation anxiety is one of the more prevalent and difficult to treat behavior problems in dogs. The associated behaviors can be undesirable to dog owners and damage the human animal bond, leading to relinquishment or return to an animal shelter. Due to the high prevalence of separation related problems in recently adopted shelter dogs, shelter staff hold a critical role in advising and educating owners on how to prevent separation anxiety post-adoption. The aim of this study was to propose a form of that preventive counseling as a means of preventing the development of separation anxiety in recently adopted shelter dogs. The efficacy of preadoption counseling in the education and prevention of separation anxiety problems was tested in a prospective, randomized, parallel-group study. Participants included 133 new owners of dogs 6 months of age and older. At the time of adoption, sixty-six of these owners were randomly selected to receive five minutes of counseling on the prevention of separation anxiety, while the remaining sixty-seven owners served as the controls. A follow-up survey regarding the signs associated with separation anxiety and other potentially related behaviors was conducted one month post adoption. Results showed that 19 owners reported their dogs as having separation anxiety. There was no significant effect of adoption counseling on the prevention of separation anxiety. Owners in both groups were equally as likely to perform most of the recommendations given during counseling. Dogs that were reported to have separation anxiety were significantly more likely than dogs without reported separation anxiety to show nervous or panicked behavior as the owner prepared to leave (P = 0.0001) and were more likely to be reported as being “needy” (P = 0.031). Having another dog in the home was not protective against the development of separation anxiety. Owners in the counseling group were more likely than those in the control group to put food inside a toy at the time of leaving the dog home alone (P = 0.0001), suggesting the counseling recommendations were indeed followed by the owners. Owner compliance supports the idea that counseling is a useful tool for owners. Separation anxiety is a disorder whose course may be difficult to alter in recently adopted shelter dogs using only basic, interventional information. Brief counseling and a toy do not effectively prevent the occurrence of this complex behavioral condition. Further investigation should be done to find more specific, effective prevention tools for owners to use in the home to minimize the development of separation anxiety and shelter should be prepared to provide interventional resources to owners whose dogs develop separation anxiety despite these efforts.     

辽宁滨海公路降噪林带模式研究

在对滨海公路噪声污染进行实时监测的基础上,利用相关文献研究成果,设计出不同声环境功能区降噪林带的基本模式:1类、2类、3类和4a类功能区的林带宽度分别为90、53、24和5 m,平均木胸径15 cm,等边三角形交错式栽植,株距分别为:3.04、3.02、2.93和2.32 m。该模式不仅为滨海公路的全线绿化建设提供了科学依据,而且为同类型的道路绿化设计提供了参考。     

广州市生态景观林带的植物现状及优化建议

营造生态效益与景观效果俱佳的园林景观,是园林建设的核心与难点.从群落结构和植株观赏效果两方面对广州市生态景观林带植物的现状进行了统计分析,包括乔木层和灌木层的密度、覆盖度、丰富度,及树种的观赏期、观赏色彩、树形.结果显示,目前林带存在物种丰富度低、部分群落过密覆盖度过高、夏秋冬3季可赏树种较少等问题.参照广州市地带性植被物种组成和群落结构,提出林带树种选择和群落构建的优化建议.