CTL-12型化学需氧量测定仪应用研究

采用CTL-12型化学需氧量测定仪测定CODCr,并与传统的重铬酸钾法比较。实验结果表明,该仪器适用于多种废水、不同浓度CODCr的测定,具有准确、简便、快速等特点。     

2009—2017年南充市城区酸雨特征分析

为了更为有效地治理酸雨污染,根据南充市环境监测中心站提供的2009—2017年降水监测数据,对南充市城区酸雨污染情况进行了分析及源解析。结果表明:2009—2017年,南充市降水pH从4.60波动上升至5.6以上,酸雨频率波动下降,酸雨污染情况有所改善;[SO4^2-]/[NO3^-]从4.92下降至0.86,酸雨污染类型从硫酸型转变为硝酸-硫酸型。同时,对比分析2014—2016年大气污染物排放源可知,NOx排放源中,工业污染源占比由14%降至11%,生活污染源由2%上升至5%;SO2排放源中,工业污染源占比由62%降至43%,生活污染源由38%上升至57%,表明南充市SO2污染已从以工业污染源为主转变为工业污染源与生活污染源并重。     

江苏北部景观生态对策研究

在对江苏北部气候、地貌、土壤、植被等景观生态要素研究的基础上，以地貌和基质为基本线索、以植被为标志建立了该地区的景观生态分类系统。该系统为二级分类系统，包括１０个景观型、３１个景观亚型。以景观亚型或景观亚型的组合为基本制图单位，编制了江苏北部１∶１００万景观生态类型图。详细分析了江苏北部稀疏植被景观、常绿针叶林景观、落叶阔叶林景观、旱地作物景观、水旱轮作景观、水田作物景观、淡水水生植被景观等主要景观型的生态问题，提出了相应的生态对策。     

An analysis of cyclists’ speed at combined pedestrian and cycle paths

Abstract

Objective: In Sweden, cyclists, pedestrians, and moped riders share the space on combined pedestrian and cycle paths, and their speeds may differ greatly. Both actual speed and speed differences can potentially influence the number of accidents on the shared paths. As a starting point, this article studies the speed component and how cyclists’ speed varies at pedestrian and cycle paths depending on the day, week, and year; road user composition; and road design.

Methods: Three data sources were used: Existing measurements of cycle speed and flow in 3 different Swedish municipalities, Eskilstuna (1 site, January–December 2015), Linköping (6 sites, 4?weeks in September–October 2015), and Stockholm (10 sites, 1–5?days in August–September 2015); complementary measurements of cycle speed and flow in Linköping (4 sites, 1–10?days in August–September 2016) and Stockholm (1 site, only part of 2?days in August 2016) were also conducted within the project, in addition to roadside observations of bicycle types at the 5 new sites.

Results: The average speed of cyclists on the paths varied between 12.5 and 26.5?km/h. As expected, the lower average speeds were found in uphill directions, near intersections, and on paths with high pedestrian flows. The higher speeds were found in downhill directions and on commuter routes. In all, 70%–95% of road users observed on pedestrian and cycle paths were cyclists, and 5%–30% were pedestrians. The most common type of bicycle was a comfort bike, followed by a trekking bike. Electric-assisted bicycles and racer bikes occurred at all sites, with proportions of 1%–10% and 1%–15%, respectively. The 2 sites with the highest proportion of electric-assisted bicycles and racer bicycles also had the highest average speeds. The differences in average speed throughout the day, week, and year could only be assessed at one of the sites. Only small differences were found, with the most noticeable being that the average speed was lower in January and February (13.8?km/h) compared to the rest of the year (15.3–16.1?km/h). The average speed was also lower during daytime (14.7?km/h) than during other parts of the day (15.4–15.8?km/h).

Conclusions: The relationship between bicycle type and measured speed was not entirely clear, but the results suggest that paths with higher proportions of electric and racer bicycles have higher average speeds. There also appears to be a connection between average speed and the width of the distribution; that is, the higher the average speed, the wider the speed distribution. More research is needed on how speed levels and speed variance affect accident risk.     

文化型海岛善行旅游发展的战略路径选择——以福建湄洲岛为例

海岛旅游发展再一次成为海洋旅游业发展的新突破口.以湄洲岛为代表的文化型海岛凭借其深厚的文化内涵和优质的海滨旅游资源成为海洋旅游业发展的生力军.从解读文化型海岛内涵及特征入手,全面剖析了湄洲岛的优势条件,从文化价值、文化需求、文化生态、文化形态等方面深入挖掘湄洲岛所含文化特性,以此构建起湄洲岛善行旅游发展的“四和四共一发展”的互动效应,探寻出一条具有文化型海岛特点的湄洲岛善行旅游发展之路.     

重点生态功能区转移支付制度的不足和完善

重点生态功能区关乎地区乃至国家的生态安全,属于限制开发区。该类功能区为提供生态产品投入大量的环境建设成本,又因限制开发导致发展权受限,需要对其进行生态补偿。作为当前生态补偿的主要方式,重点生态功能区转移支付制度在资金分配、资金使用、监督考核和激励机制方面存在不足,因此提出确定生态环境保护为转移支付的主要目标、健全资金用途监管和绩效评估制度、补充适用横向生态补偿制度等措施予以完善。     

离子型稀土尾矿残留铵缓释性分析

为探究尾矿残留NH₄⁺的缓释性,以江西信丰离子型稀土矿为研究对象,柱浸制备浸出尾矿,去离子水淋洗尾矿.按照淋洗→封存→再淋洗的步骤,考察了淋洗尾矿不同含水率（1.3%,15%,35%,250%）,不同封存时间（15,30,60,120,180,195,210,240d）和不同传质机制（对流、扩散）下NH₄⁺的淋出量.结果表明：尾矿再淋洗仍能淋出NH₄⁺,NH₄⁺淋出量受含水率、封存时间和传质方式影响;含水率≥15%时,NH₄⁺淋出量整体随时间推移而递增;同时间下,NH₄⁺淋出量整体随含水率增大而增大;其他条件相同时,对流传质下NH₄⁺淋出量大于扩散.尾矿再次淋出的NH₄⁺是可交换态NH₄⁺向水溶态NH₄⁺转化的结果.     

农村居民点多维形态空间格局与耦合类型

农村居民点空间形态的系统认识与分类研究是乡村整治和科学实施乡村振兴的重要基础。以北京市平谷区为研究区域,从规模、结构和功能三个维度构建农村居民点形态识别指标,使用多因素综合评价法得到275个行政村的规模强度、结构合理度和功能协调度,借助ArcGIS和GeoDa依次对三者进行空间关联分析,进而基于三维特征划分出8种农村居民点耦合类型。结果表明：（1）平谷区农村居民点规模强度、结构合理度和功能协调度在空间上均存在空间集聚的正相关性,空间分布分别呈现“递进式”“圈层式”和“镶嵌式”格局。（2）平谷区农村居民点多维形态的地域差异性显著,全区62.8%的村庄表现为低强度,51.3%的村庄表现为结构不合理,61.4%的村庄表现为功能不协调。（3）平谷区以T1-S1-F2型（高强度—合理—不协调型）和T1-S2-F2型（高强度—不合理—不协调型）的农村居民点为主,两者共占农村居民点总量的60.1%,前者主要分布在距离城区较近的乡镇,后者主要分布在距离城区较远的北部、西南部和东部的山地丘陵区。（4）规模强度高、结构不合理、功能不协调的农村居民点类型是平谷区乡村协同发展的主要障碍,政策制度、技术工程、产业扶持等差别化治理模式是推进农村居民点可持续性利用和乡村振兴的关键。     

哈尔滨市一次大气污染过程及潜在源分析

本研究以2018年12月10~13日哈尔滨市一次严重的空气污染事件为研究对象,分析了此次污染过程的概况、成因以及污染的潜在源区.结果表明：此次空气污染过程以PM_2.5影响为主,污染类型由10日00：00~11日17：00的偏燃煤型发展为11日17：00~13日15：00的二次气溶胶复合污染,最终在13日15：00后稳定为偏燃煤型.从天气形势和风速风向分析可知此次10~13日的污染过程与不利气象扩散条件也是密不可分的.模拟的48h后向轨迹经过聚类分析主要分为4类,大部分来自内蒙古、吉林等方向,70.83%的轨迹PM_2.5超标,表明来自这些方向的污染气团对哈尔滨市的空气质量影响较大;而通过对模拟的48h后向轨迹进行PSCF、CWT分析,发现哈尔滨的WPSCF和WCWT分布特征类似,WPSCF和WCWT的高值主要集中在哈尔滨本地的双城、巴彦、阿城、吉林省的中部、西部地区等地区,以及大庆、绥化等地区,说明这些区域都是哈尔滨市PM_2.5的潜在源地.     

不敏感装药高温相变影响机制研究进展与思考

综述了HMX、CL-20以FOX-7等未来不敏感装药主要候选组分的相变研究进展,归纳了高温相变对安全性带来影响的几个原因,主要包括炸药本身的稳定性下降、炸药密度改变及炸药内部缺陷增加的原因。针对如何降低高温相变对不敏感装药安全性的影响进行了初步思考,认为目前为了降低高温相变对炸药安全性的影响,主要手段仍是对相变进行一定程度的抑制,而共晶技术、包覆技术、晶型控制剂抑制技术和配方抑制相变技术是未来相变抑制技术的主要研究方向。