雕塑的永恒性在环境当中的退化

古代雕塑具有记录历史、纪念人物形象、宣传、装饰环境的作用。现代雕塑的表现形式由写实到抽象,材料更轻便、廉价,在环境中存在的时间越来越短了。雕塑本身具有的永恒性已经逐渐地退化了,这种退化源自于社会的更替、人文环境的变化和新材料的出现。     

高压水射流粉碎的压力释放效应

高压水射流粉碎是一个对物料颗粒加压后再将压力释放的过程,在这一过程中由于颗粒受压存储的弹性应变能的迅速释放,使颗粒以拉应力形式破坏实现颗粒的压力释放粉碎.笔者的理论分析和实验研究表明:当压力达到某一值后释放,可以实现颗粒的破裂粉碎;实现压力释放粉碎作用的应力低于材料的抗压强度,但高于材料的抗拉强度;而且压力越高,粉碎效果越好.该研究成果为探索高压水射流粉碎机理和粉碎实践提供了有力的依据.     

基于POI数据的河道水质空间分布与相关分析

基于苏州古城区河道14个采样点的水质数据和兴趣点(POI)数据,分析古城河水质与周围POI类型之间的相关性.利用主成分分析计算每个采样点的综合水质指标;基于GIS空间分析技术,计算代表人类干扰强度的POI单类型点密度指数和POI多类型核密度指数;最后运用Pearson相关分析探讨POI数据对水质的影响.结果表明,水质高...     

南昌某城市污水处理厂进水浓度低成因分析研究

针对南昌某城市污水处理厂进水浓度低的现象,为明确造成污水处理厂进水浓度低的原因,通过对南昌市2018—2020年降雨特征对污水处理厂进水污染物浓度影响的统计分析,估算了降水对雨污合流制管网污水浓度的影响.考察了合流制管网4个污水提升泵站、污水处理厂的日处理水量,结合水量平衡三角法,核算地下水、河水、雨水的渗入.以及利用倒排查法对源居民小区内/外-污水提升泵站-污水处理厂的水质沿程采样分析,得出相关结论.研究结果表明：①2018—2019年上半年污水处理厂进水COD在降雨后2~5 h进水浓度明显降低;但2019年下半年—2020年这种相关性明显削弱.②污水处理厂日进水COD受泵站的日流量的影响,呈显著负相关.③水量三角平衡定量分析表明地下水、河水混入28%~38%,雨水混入11%~18%.④水质沿程的分析显示小区到某些泵站的浓度明显降低,雨天COD、氨氮浓度分别减少了69.78%、75.21%,晴天COD、氨氮浓度分别降低了66.78%、76.94%,表明相应的小区外-泵站段的市政管网是污水处理厂进水浓度降低的关键管段,亟需进一步重点排查和改造.⑤老旧小区排水浓度受天气的影响远比新小区大,雨天分别比晴天减少79.23%、67.87%和54.40%,可能发生了大量雨水混入.     

Conserving and managing the subnivium

In regions where snowfall historically has been a defining seasonal characteristic of the landscape, warming winters have reduced the depth, duration, and extent of snowpack. However, most management and conservation has focused on how aboveground wildlife will be affected by altered snow conditions, even though the majority of species that persist through the winter do so under the snowpack in a thermally stable refugium: the subnivium. Shortened winters, forest management practices, and winter recreation can alter subnivium conditions by increasing snow compaction and compromising thermal stability at the soil–snow interface. To help slow the loss of the subnivium in the face of rapidly changing winter conditions, we suggest managers adopt regional conservation plans for identifying threatened snow‐covered environments; measure and predict the effects land cover and habitat management has on local subnivium conditions; and control the timing and distribution of activities that disturb and compact snow cover (e.g., silvicultural practices, snow recreation, and road and trail maintenance). As a case study, we developed a spatially explicit model of subnivium presence in a working landscape of the Chequamegon National Forest, Wisconsin. We identified landscapes where winter recreation and management practices could threaten potentially important areas for subnivium persistence. Similar modeling approaches could inform management decisions related to subnivium conservation. Current climate projections predict that snow seasons will change rapidly in many regions, and as result, we advocate for the immediate recognition, conservation, and management of the subnivium and its dependent species.     

基于保护优先的我国古建筑旅游发展研究

古建筑旅游是目前我国旅游发展的一大趋势，古建筑保护与旅游发展的矛盾是我国古建筑实现可持续旅游发展与科学保护的核心问题。从旅游学角度研究古建筑的保护及其发展，首先对古建筑的旅游认识进行了阐述，剖析了古建筑保护面临的问题，进而提出若干建议与对策，以期能“延年益寿”和可持续发展。     

DQ—500型惰气灭火装置

本文提出扑灭瓦斯矿井火灾的惰气灭火装置,并介绍了该装置的工作原理,构造及其应用。研究了风油比与燃气成分的关系;阐述了风油比自控系统对保证燃气成分符合灭火要求的重要意义和作用。本文还对国内外同类灭火装置性能进行比较。通过试验表明,该装置既能扑灭矿井火灾又能抑制瓦斯爆炸,是处理瓦斯矿井火灾理想的灭火新装备。     

黄龙溪古镇生态旅游开发初步构想

以自然资源为基础的生态旅游作为一种可持续发展的旅游形式,应成为大多数旅游区的发展模式。黄龙溪是成都八大风景区五大类型中田园古镇的典型代表,其丰富的自然景观和人文景观受到越来越多游客的青睐,有关部门在制定黄龙溪古镇旅游规划时应体现出生态的精神,开发与保护共举,实现古镇旅游的可持续发展。     

Point of decision: when do pigeons decide to head home?

Pigeons released away from their loft usually fly around at the release site for a while before they finally leave. Visual observations had suggested that the moment when the birds decide to head home is associated with a certain change in flying style. To see whether this change is also reflected by GPS-recorded tracks, a group of pigeons equipped with flight recorders was released at two sites about 10 km from their home loft. The initial part of their flight paths was analyzed in order to find objective criteria indicating the point of decision. We selected the highest increase in steadiness as the best estimate for the moment of decision. This criterion allows us to divide the pigeons’ paths in two distinct phases, an initial phase and the homing phase, with the moment of decision, on an average, 2 min after release. The moment of decision marks a change in behavior, with a significant increase in steadiness and flying speed and headings significantly closer to the home direction. The behavior of the individual birds at the two sites was not correlated, suggesting no pronounced individual traits for the length of the initial phase. The behavior during this phase seems to be controlled by flight preparation, exploration, and non-navigational motivations rather than by navigational necessities alone. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

丽江大研古城古建筑消防安全对策

通过对丽江大研古城的实地调查,分析了古城古建筑的火灾隐患,提出了古城消防安全的对策,以更好地保证我国古建筑的消防安全.