新加坡城市树木保护及精细化管理策略研究

城市树木的保护管理是城市绿化的关 键性内容。新加坡城市树木保护及精细化管理 归纳为贯穿城市树木全生命周期,具有复杂适应 性和高效能的“综合治理”模式。主要策略体 现在战略目标引领和政府主导市场参与的管理 机制,法规体系、城市空间政策到实施的全过 程管理,树艺师国际认证和人才执业制度保障, 专业化和数字化技术应用的精细化日常管理, 智慧高效能的城市树木信息管理系统支撑,多 元化社会管理与公众参与机制等方面。对比我 国与新加坡的差异,对我国城市树木保护管理 提出战略化目标、法制化保障、系统化管理、职 业化建设、智慧化支持、多元化公众参与的“治 理”策略建议。     

煅烧温度对环保型莫来石多孔陶瓷结构和性能的影响

莫来石多孔陶瓷因其高强度和耐腐蚀等性能得到广泛地应用。然而,由于合成莫来石的原料高岭土的不可再生性及持续上涨的价格,寻找廉价易得的替代原料对于合成莫来石多孔陶瓷迫在眉睫。建筑废弃物的成分与高岭土相似,可作为高岭土的可行替代品之一。以建筑废弃物和Al₂O₃为主要原料,AlF₃为晶须催化剂,B₂O₃为烧结助剂,成功制备了环保型莫来石多孔陶瓷。通过阿基米德排水法、XRD和SEM等表征手段,深入探究了多孔陶瓷的晶相、微观形貌和物理化学特性。同时,研究了煅烧温度对莫来石多孔陶瓷结构和性能的影响规律及作用机制。结果表明,适当提升煅烧温度有助于莫来石晶须的生成,但过高的温度会导致晶须粗化和晶粒增大。当煅烧温度为1 200 ℃时,莫来石晶须的生长形貌最佳,晶须直径约为0.05—0.1 μm、长度为0.5—1 μm、长径比在15—20之间。随着煅烧温度增加,莫来石多孔陶瓷的开口孔隙率不断降低,抗折强度不断增强。当煅烧温度为1 200 ℃时,样品的开口孔隙率达到（61.78±0.72 ）%,抗折强度达到（3.74±0.46） MPa。因此,以建筑废弃物为主要原料可成功制备具有高气孔率的莫来石多孔陶瓷。本研究为建筑废弃物合成莫来石多孔陶瓷提供了可靠的理论支持,对降低生产成本及推动建筑废弃物资源化再利用等有重要理论价值和实际意义。     

Genome-Wide Identification of TaSAUR Gene Family Members in Hexaploid Wheat and Functional Characterization of TaSAUR66-5B in Improving Nitrogen Use Efficiency

Excessive input of nitrogen fertilizer not only causes a great waste of resources but brings about a series of ecological and environmental problems. Although Small Auxin Up-regulated RNAs (SAURs) participate in diverse biological processes, the function of SAURs in the nitrogen starvation response has not been well-studied. Here, we identified 308 TaSAURs in wheat and divided them into 10 subfamilies. The promoter regions of most TaSAURs contain hormone responsive elements, and their expression levels change under the treatment of different hormones, such as IAA, MeJA, and ABA. Interestingly, overexpression of one of the TaSAUR family members, a nitrogen starvation responsive gene, TaSAUR66-5B, can promote the growth of Arabidopsis and wheat roots. In addition, overexpression of TaSAUR66-5B in Arabidopsis up-regulates the expression levels of auxin biosynthesis related genes, suggesting that overexpression TaSAUR66-5B may promote root growth by increasing the biosynthesis of auxin. Furthermore, overexpression of TaSAUR66-5B in wheat can increase the biomass and grain yields of transgenic plants, as well as the nitrogen concentration and accumulation of both shoots and grains, especially under low nitrogen conditions. This study provides important genomic information of the TaSAUR gene family and lays a foundation for elucidating the functions of TaSAURs in improving nitrogen utilization efficiency in wheat.     

多层住宅顶层改善措施

顶层住宅由于其用水、防水、隔热，上下楼不便等缺陷，不受居民的欢迎，在分配及销售上均存在着许多问题。本文对改善顶层住房的舒适性方面，提出了多种综合性措施，将顶层的不利因素转化为有利因素，具有一定的推广价值。     

电缆电视的传输系统

本文证明了放大器的等利用差原理。按此原理设计，传输系统的放大器将有最大实用功率输出。详细分析了环境温度对传输系统的影响，阐述了一些新概念，并提出一种论理严密，实用性强的新设计方法。     

地热资源在供热空调开发利用中的研究现状和进展

本文首先回顾了国内外地热资源在供热空调方面的应用历程及研究现状,重点介绍了当前地热供暖空调的新技术。其次,就目前系统开发设计中遇到的问题提出并分析了应采取的措施,为地热资源的合理利用提供了依据。     

Responses of Growth,Oxidative Injury and Chloroplast Ultrastructure in Leaves of Lolium perenne and Festuca arundinacea to Elevated O3 Concentrations

The effects of increasing atmospheric ozone (O₃) concentrations on cool-season plant species have been well studied, but little is known about the physiological responses of cool-season turfgrass species such as Lolium perenne and Festuca arundinacea exposed to short-term acute pollution with elevated O₃ concentrations (80 ppb and 160 ppb, 9 h d⁻¹) for 14 days, which are widely planted in urban areas of Northern China. The current study aimed to investigate and compare O₃ sensitivity and differential changes in growth, oxidative injury, antioxidative enzyme activities, and chloroplast ultrastructure between the two turf-type plant species. The results showed that O₃ decreased significantly biomass regardless of plant species. Under 160 ppb O₃, total biomass of L. perenne and F. arundinacea significantly decreased by 55.3% and 47.8% (p < 0.05), respectively. No significant changes were found in visible injury and photosynthetic pigment contents in leaves of the two grass species exposed to 80 ppb O₃, except for 160 ppb O₃. However, both 80 ppb and 160 ppb O₃ exposure induced heavily oxidative stress by high accumulation of malondialdehyde and reactive oxygen species in leaves and damage in chloroplast ultrastructure regardless of plant species. Elevated O₃ concentration (80 ppb) increased significantly the activities of superoxide dismutase, catalase and peroxidaseby 77.8%, 1.14-foil and 34.3% in L. perenne leaves, and 19.2%, 78.4% and 1.72-fold in F. arundinacea leaves, respectively. These results showed that F. arundinacea showed higher O₃ tolerance than L. perenne. The damage extent by elevated O₃ concentrations could be underestimated only by evaluating foliar injury or chlorophyll content without considering the internal physiological changes, especially in chloroplast ultrastructure and ROS accumulation.     

关于主城区电网下地问题的研究

本文根据重庆市渝中区电网下地规划、实施案例,从而总结分析研究主城区电网下地的方案比选以及具体实施步骤及其关键环节。     

隐退的岗丘(一)

本文从一张大连的旧照片说起,通过描绘和分析人们对于高差与坡度的感觉改变,讲述了在大连城市开发中自然地貌特征的逐渐隐退。     

城中村问题调查与分析

以华北地区为主要研究对象,对秦皇岛山东堡地区进行了深入调研,从中发现城中村存在的一些共性问题,通过分析找出了症结所在并提出合理的解决方案。