排序方式: 共有29条查询结果,搜索用时 15 毫秒
1.
- The spectral form of wind waves is investigated based on the ocean wave data observed at three nearshore stations of Taiwan. In this study, the generalized forms of Pierson-Moskowitz spectrum and JONSWAP spectrum are used to describe the local wave spectrum by selecting suitable spectral form parameters. It is shown that, at a specific site, the similarity of wave spectral form exists. Thus it is possible to use a representative spectral form for a given nearshore region to describe the wave spectrum at this nearshore. On the other hand, the effects of relative water depth on spectral form are examined. The feasibility of two spectral models in finite water depth is evaluated by using the same field wave data. 相似文献
2.
Zhang Guanglei Ranjith P. G. Perera M. S. A. Lu Yiyu Choi Xavier 《Natural Resources Research》2019,28(4):1639-1660
Natural Resources Research - High-volatile bituminous coal samples were reacted in deionized water with supercritical CO2 (ScCO2–water) under simulated in situ pressure and temperature... 相似文献
3.
Along with carbon emission regulations launched by governments and consumers’ rising concerns about climate changes and global carbon footprint, interests of academia and industry have risen in carbon-efficient supply chain management. This research focuses on some product supply chain to make a literature review-based investigation on proposing a theoretical framework. We also solve potential research issues of how diverse carbon emission regulations can work on supply chain performance as well as emission; in what way we can find coordination mechanisms and optimal policies for supply chain operations to abate emission and enhance system profitability within different scenarios; and also to evaluate the effect on emission reduction for each emission regulation aforementioned through comparing their associated supply chain performances and system emission. Both practitioners in industry and academia might find this study useful, as it generates concepts with a formal framework of potential and values theoretical issues in the emerging field of carbon-efficient supply chain management which combines carbon emission regulations with mature operation management to enrich the theory of supply chain management. This study is perhaps to be valuable and constructive both for operational decisions in firms and for the enactment as well as implementation of emission-reduction regulations. This study should activate further potential researches. 相似文献
4.
铈硼硅石是一种罕见的稀土矿物,由于它含有某些化学性质近似的元素,故分析难度较大。本文研究了应用纸色层法和离子选择性电极法对铈硼硅石中某些主要成分和微成分的分离和测定条件,设计了较合理的铈硼硅石微量全分析流程。该流程也适合类似矿物的分析,与常法比较,本法具有快速、准确、成本低和用样少等优点。 相似文献
5.
山西省层状云飞机云物理观测试验结果分析 总被引:1,自引:0,他引:1
利用山西省2008年-2010年64架次云结构的粒子测量系统(DMT)探测资料,配合地面观测和卫星资料统计分析了层状云系的宏微观特征。发现:降水性层状云低云含水量垂直方向上平均为0.03g,m^3,中云含水量垂直方向上平均为0.05g/m30对比分析降水云和非降水云系的微物理特征量,两者存在显著的差异,降水性层状云云粒子有效半径要达到10μm-14μm。对云系不同温度层的微物理特征和云中水分按不同粒子尺度的分配特征进行了对比分析,结果表明:降水性层状云在垂直方向上的微物理结构特征非常明显,也是分层的。高层主要是冰相粒子,主要是冰雪晶,随高度降低冰雪晶的尺度增大,在四个典型温度层的观测中,LWC、云粒子及降水的浓度、尺度相较有很大不同。云中水分按不同粒子尺度的分配可以看出,直径20μm、30μm的粒子含水量较高,对云中液态水含量的贡献较大,降水粒子主要由20μm、30μm的粒子转化。 相似文献
6.
7.
8.
基于改进高斯两步移动搜索法的深圳市公园绿地可达性评价 总被引:2,自引:0,他引:2
公园绿地可达性是衡量城市宜居水平的重要指标。针对传统可达性分析多用统计数据开展评估而导致的供需尺度失衡问题,论文以深圳为例,采用公园绿地空间矢量数据和手机信令数据获取供需空间分布,采用高斯两步移动搜索法计算交通小区(TAZ)尺度公园绿地可达性,并结合可达性结果及供需、交通情况聚类,剖析可达性差异化模式及成因。主要结论如下:① 通过改进传统可达性计算数据源和高斯两步移动搜索模型,建立城市中微观尺度公园绿地可达性评价及成因研究框架,可更精确地评估优化城市公园绿地可达性;② 深圳市公园绿地综合可达性整体水平较高,但存在明显的从中心向外围递减的趋势,社区公园可达性差异与公园绿地供需不匹配是造成各区域可达性差异大的重要原因;③ 根据K均值聚类分析结果,将深圳市TAZ单元分成低供给低需求低可达性区、中供给低需求中可达性区、高供给高需求中可达性区、高供给低需求高可达性区,各类区域具有差异化的可达性内涵、特征和成因;④ 公园绿地可达性提升可针对不同分区特征,通过公园布局优化、道路建设和居住区规划布局等差异化方式实现。研究充实了城市公园绿地可达性评价案例,提出的基于手机信令数据和高斯两步移动搜索法的可达性分析方法不仅可应用于城市公园绿地布局与规划,也可为其他地理现象可达性分析提供思路参考。 相似文献
9.
10.
煤炭资源是我国重要的一次性能源,科学监测与评估矿区生态健康,对于维持经济发展与生态健康的平衡至关重要。本文选取位于山西省的3处典型煤炭矿区,基于2001—2021年的Landsat遥感数据,利用目视解译方法对露天矿区进行了多年用地类型演变格局分析;并分别对3处典型矿区的绿度、湿度、干度、热度进行了估算,应用知识粒度熵的权重计算方法,综合构建了矿区遥感生态指数(RSEI),完成了矿区生态健康多年遥感诊断。结果表明,两处露天矿区呈现边开采边复垦的生产模式,各有半数的研究年份RESI区域均值达到0.5以上;地下矿区的开采工作基本不造成地上扰动,其2001年以来的生态健康状况较为稳定,RSEI均值在0.7上下浮动;3处矿区2021年的RSEI均值分别为0.53、0.48、0.70。本文改进了传统的遥感生态指数构建方法,为煤炭矿区的长时序生态监测与遥感诊断提供了科学支撑。 相似文献