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1.
工业用地供应行为的演化是工业经济发展的重要体现,分析工业用地供应规模的时空变化特征,有利于推进土地供给侧结构性改革,促进工业高质量发展,优化国土空间格局.基于重庆市2009~2018年工业用地供应公告数据,建立重庆市工业用地供应数据库,运用基尼系数、核密度分布、冷热点分析和趋势面分析方法,分析重庆市工业用地供应规模的时空变化规律.结果 表明:(1)重庆市工业用地供应规模总体上处于波动下降趋势,供应的区位呈现较为明显的东北-西南方向分布.区位基尼系数具有波动性特征,市域和分区都在空间分布不均衡和均衡间反复.(2)工业用地供应点规模呈现出“主环-斑点”式空间布局模式,高密度核心逐渐向主城区中心聚集.供应规模的热点区县在主城区的东西两侧变动,冷点区集中在渝东北角.(3)重庆市的中心城区及其西部和南部具有较大的工业用地供应规模,为建设成渝地区双城经济圈奠定了较好基础.  相似文献   
2.
党晓贝  何亚平  汪箭 《火灾科学》2018,27(4):213-221
采用实验和FDS数值模拟相结合的方法,探讨了边沿高度对油池火燃烧特性的影响。在实验部分,研究了燃烧速率和表观火焰高度随边沿高度的变化趋势,并分别分析了各个阶段的热反馈机制。在实验获得不同尺度、边沿高度正庚烷油池火燃烧速率的前提下,建立相应尺度的不同边沿高度油池火的Fire Dynamics Simulator(FDS)计算模型以针对火焰高度进行了数值模拟研究,分析了实际火焰高度、火焰下探高度随边沿高度的变化趋势,并提出了相关的无量纲拟合式。  相似文献   
3.
大九湖是南水北调中线工程的重要水源涵养地之一。为了解实施生态修复工程后浮游动物群落结构特征及水质污染情况,于2014年11月(枯水期)、2015年5月(平水期)和9月(丰水期)进行了3次采样调查。研究表明:共检出后生浮游动物36种,其中桡足类2种、枝角类5种和轮虫29种,轮虫丰度在3次采样中均占总丰度的80%以上,仅有的几种枝角类和桡足类也是小型种类或以幼体为主。11月优势种是寡污-β中污型-螺形龟甲轮虫(Keratella cochlearis)和晶囊轮虫(Asplachna sp.);5月优势种为寡污-β中污和β中污型-螺形龟甲轮虫、迈氏三肢轮虫(Filinia maior)、无棘螺形龟甲轮虫(Keratella cochlearis tecta)、广生多肢轮虫(Polyarthra vulgaris)和萼花臂尾轮虫(Brachionus calyciflorus);9月优势种是β-中污型-裂足臂尾轮虫(Brachionus diversicornis)、迈氏三肢轮虫和剪形臂尾轮虫(Brachionus forficula)。冗余分析(RDA)表明高锰酸盐指数(CODMn)是影响后生浮游动物污染类型分布的最关键环境因子。 关键词: 大九湖;后生浮游动物;污染类型;高山湿地湖泊  相似文献   
4.
Research suggests that encouraging motivated residents to reach out to others in their social network is an effective strategy for increasing the scale and speed of conservation action adoption. However, little is known about how to effectively encourage large numbers of residents to reach out to others about conservation causes. We examined the influence of normative and efficacy-based messaging at motivating residents to engage in and to encourage others to participate in native plant gardening in their community. To do so, we conducted a field experiment with messages on mailings and tracked native plant vouchers used. Efficacy messages tended to be more effective than normative messages at increasing residents’ willingness to reach out to others to encourage conservation action, as indicated by a several percentage point increase in native plant voucher use by residents’ friends and neighbors. Messages sometimes had different impacts on residents based on past behaviors and perceptions related to native plant gardening. Among these subgroups, efficacy and combined efficacy and norm messages most effectively encouraged individual and collective actions, as indicated by increased voucher usage. Our findings suggest that interventions that build residents’ efficacy for engaging in a conservation behavior and for reaching out to others may be a promising path forward for outreach. However, given our results were significant at a false discovery rate cutoff of 0.25 but not 0.05, more experimental trials are needed to determine the robustness of these trends.  相似文献   
5.
Visibility degradation, one of the most noticeable indicators of poor air quality, can occur despite relatively low levels of particulate matter when the risk to human health is low. The availability of timely and reliable visibility forecasts can provide a more comprehensive understanding of the anticipated air quality conditions to better inform local jurisdictions and the public. This paper describes the development of a visibility forecasting modeling framework, which leverages the existing air quality and meteorological forecasts from Canada’s operational Regional Air Quality Deterministic Prediction System (RAQDPS) for the Lower Fraser Valley of British Columbia. A baseline model (GM-IMPROVE) was constructed using the revised IMPROVE algorithm based on unprocessed forecasts from the RAQDPS. Three additional prototypes (UMOS-HYB, GM-MLR, GM-RF) were also developed and assessed for forecast performance of up to 48 hr lead time during various air quality and meteorological conditions. Forecast performance was assessed by examining their ability to provide both numerical and categorical forecasts in the form of 1-hr total extinction and Visual Air Quality Ratings (VAQR), respectively. While GM-IMPROVE generally overestimated extinction more than twofold, it had skill in forecasting the relative species contribution to visibility impairment, including ammonium sulfate and ammonium nitrate. Both statistical prototypes, GM-MLR and GM-RF, performed well in forecasting 1-hr extinction during daylight hours, with correlation coefficients (R) ranging from 0.59 to 0.77. UMOS-HYB, a prototype based on postprocessed air quality forecasts without additional statistical modeling, provided reasonable forecasts during most daylight hours. In terms of categorical forecasts, the best prototype was approximately 75 to 87% correct, when forecasting for a condensed three-category VAQR. A case study, focusing on a poor visual air quality yet low Air Quality Health Index episode, illustrated that the statistical prototypes were able to provide timely and skillful visibility forecasts with lead time up to 48 hr.

Implications: This study describes the development of a visibility forecasting modeling framework, which leverages the existing air quality and meteorological forecasts from Canada’s operational Regional Air Quality Deterministic Prediction System. The main applications include tourism and recreation planning, input into air quality management programs, and educational outreach. Visibility forecasts, when supplemented with the existing air quality and health based forecasts, can assist jurisdictions to anticipate the visual air quality impacts as perceived by the public, which can potentially assist in formulating the appropriate air quality bulletins and recommendations.  相似文献   

6.
采用2013年环境空气自动监测数据,分析杭州市空气中黑碳质量浓度的变化规律,并对变化特征的产生原因进行探讨。结果表明:黑碳测定年均值为4.10μg/m3,日变化有明显双峰结构,峰值出现在早7时和晚8时左右;从季节看,黑碳质量浓度冬季高(5.20μg/m3)、夏季低(3.00μg/m3);黑碳质量浓度与NO2、CO、PM10、PM2.5显著相关,与O3、风速、气温呈负相关,降水对黑碳的清除作用明显。  相似文献   
7.
通过对广东省阳春市春湾镇龙虎坑村柴草自燃现象与地震活动时间序列以及对自燃区地质地貌、断层气测量等研究,认为,自燃现象与强震活动有密切的对应关系;柴草自燃现象是区域构造应力场加强的窗口效应.  相似文献   
8.
面对人口老龄化对经济发展的影响.应以养老和健康保障为先导.逐步加大对社会保障基金的投入.充实基本养老保险和医疗保险基金.建立和完善与生产力发展水平相适应的社会保障制度.继续推进社会保障社会化和产业结构调整的力度.建议政府应大力发展老龄产业。政府必须从实际出发.坚持科学发展观.逐步建立和完善老年社会养老制度和福利制度.根据老年消费市场状况.规范、引导投资.调整、优化产业结构用产业化、市场化、社会化的新运行机制.推进安老、养老产业的发展.根据老年人的不同需求,有计划的发展老龄产业、开发老年用品.增设老年服务项目.满足老年人在物质和文化方面的发展需要.以促使人口老龄化与经济的协调发展。  相似文献   
9.
Progress in Restoration of the Mauritius Kestrel   总被引:1,自引:0,他引:1  
In the 1970s, the Mauritius Kestrel ( Falco punctatus ) was the most endangered bird of prey in the world, at one time with only two known pairs surviving in the remnant native forest of the Black River Gorges (ca. 4,000 ha). At the end of the 1991–1992 breeding season, a minimum of 30 nesting pairs and more than 170 individuals were distributed in four separate forested areas, thanks mainly to manipulation of the reproductive potential of the wild pairs, to captive propagation, and to reintroduction (restocking). Since 1984, 139 young have been reared from 618 eggs laid by captive kestrels, and 147 from 265 wild eggs incubated and hatched in the laboratory; 235 young kestrels have been released on Mauritius by hacking and fostering. Adjustments in feeding and nesting habits of kestrels hacked and released outside the Black River Gorges in areas dominated by exotic vegetation and agriculture have allowed these kestrels to survive and reproduce in an array of previously unused habitats. Now that the kestrels have been released from dependence on the remnant and dying native forest, a viable population of more than 100 nesting pairs should be achievable in a few more years.  相似文献   
10.
三峡库区几种林下苔藓的保水功能   总被引:6,自引:0,他引:6  
通过对三峡库区三种森林类型(松栎混交林、栓皮栎纯林、马尾松纯林)林下苔藓储量调查分析及其持水特性试验,得到不同森林类型林下苔藓储量、最大持水量、吸水速率等水文特征参数。结果表明,马尾松纯林林下苔藓储量最大(12.93t/hm^2),松栎混交林和栓皮栎纯林林下苔藓储量相同(9.47t/hm^2)。松栎混交林林下苔藓最大持水量为5.36mm,栓皮栎纯林为5.73mm,马尾松纯林为6.26mm。研究结果还表明,三峡库区林下苔藓持水量随时间变化过程与森林类型无关。在只有苔藓覆盖情况下,不同森林类型林内不产生水分下渗和地表径流时的最大降雨量和最大降雨雨强分别为:松栎混交林林地5.36mm,5.820mm/h;马尾松纯林林地6.26mm,7.420mm/h;栓皮栎纯林林地5.73mm,6.060mm/h。  相似文献   
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