空调病房真菌气溶胶浓度及粒径分布特征

医院室内空气真菌污染会影响医护人员、病人及陪护人员的健康,其影响程度不仅与空气真菌的种类和浓度有关,还与真菌气溶胶粒径及分布特征有关,不同粒径的真菌气溶胶影响人体健康的作用机制不同.本研究对重庆某综合医院的普通病房进行空气真菌取样,系统分析了病房空气真菌浓度、种属及粒径分布特征.通过分析实验数据,发现病房空气真菌浓度与病人患病类型及人员密度无关,主要影响因素为温湿度与季节变化.冬夏各科室病房真菌粒径分布特征大致呈正态分布,粒径的百分比从Ⅰ级~Ⅲ级各级所占比例逐渐增大,Ⅲ级~Ⅴ级所占比例总体最大,Ⅴ级~Ⅵ级所占比例逐渐降低.冬夏不同科室病房的空气真菌孢子中值直径没有显著差异,真菌孢子的中值直径小于3.19μm.病房冬夏优势菌属基本相同,主要为青霉属、曲霉属及交链孢霉属,与其它建筑相比并无显著性差异.因此,病房空调系统设计应提高对粒径为1.1~4.7μm真菌孢子的过滤效率,病房的日常卫生维护与空调系统运行管理时应有针对性地选择适宜的抑菌除菌方法和设备.     

Characterization and prediction of highway runoff constituent event mean concentration

Highway stormwater runoff quality data were collected from throughout California during 2000-2003. Samples were analyzed for conventional pollutants (pH, conductivity, hardness, and temperature); aggregates (TSS, TDS, TOC, DOC); total and dissolved metals (As, Cd, Cr, Cu, Ni, Pb, and Zn); and nutrients (NO(3)-N, TKN, total P, and ortho-P). Storm event and site characteristics for each sampling site were recorded. A statistical summary for chemical characteristics of highway runoff is provided based on statewide urban and non-urban highways. Constituent event mean concentrations (EMCs) were generally higher in urban highways than in non-urban highways. The chemical characteristics of highway runoff in California were compared with national highway runoff chemical characterization data. The results obtained in California were generally similar to those found in other states. The median EMC for Pb measured in studies conducted in previous decades was much higher than the current median Pb EMC in California. The lower Pb EMC in California compared to previous highway runoff monitoring is believed to be due to the elimination of leaded gasoline. An attempt was also made to identify surrogate constituents within a general family of water quality categories using Spearman correlations and selected pairs with Spearman coefficients greater than 0.8. The strongest correlations were observed among parameters associated with dissolved minerals (EC, TDS, and chloride); organic carbon (TOC and DOC); petroleum hydrocarbons (TPH and O & G); and particulate matter (TSS and turbidity). Within the metals category, total iron concentration was highly correlated with most total metal concentrations. The correlations between total and dissolved concentrations were all less than 0.8, even between total and dissolved concentrations of the same metals. Multiple linear regression (MLR) analyses were performed to evaluate the impact of various site and storm event variables on highway runoff constituent EMCs. Parameters found to have significant impacts on highway runoff constituent EMCs include: total event rainfall (TER); cumulative seasonal rainfall (CSR); antecedent dry period (ADP); contributing drainage area (DA); and annual average daily traffic (AADT). Surrounding land use and geographic regions were also determined to have a significant impact on runoff quality. The MLR model was also used to predict constituent EMCs. Model performance determined by comparing predicted and measured values showed good agreement for most constituents.     

Channel and Perennial Flow Initiation in Headwater Streams: Management Implications of Variability in Source-Area Size

Despite increasing attention to management of headwater streams as sources of water, sediment, and wood to downstream rivers, the extent of headwater channels and perennial flow remain poorly known and inaccurately depicted on topographic maps and in digital hydrographic data. This study reports field mapping of channel head and perennial flow initiation locations in forested landscapes underlain by sandstone and basalt lithologies in Washington State, USA. Contributing source areas were delineated for each feature using a digital elevation model (DEM) as well as a Global Positioning System device in the field. Systematic source area–slope relationships described in other landscapes were not evident for channel heads in either lithology. In addition, substantial variability in DEM-derived source area sizes relative to field-delineated source areas indicates that in this area, identification of an area–slope relationship, should one even exist, would be difficult. However, channel heads and stream heads, here defined as the start of perennial flow, appear to be co-located within both of the lithologies, which together with lateral expansion and contraction of surface water around channel heads on a seasonal cycle in the basalt lithology, suggest a controlling influence of bedrock springs for that location. While management strategies for determining locations of channel heads and perennial flow initiation in comparable areas could assign standard source area sizes based on limited field data collection within that landscape, field-mapped source areas that support perennial flow are much smaller than recognized by current Washington State regulations.     

村镇小型生活垃圾热处理炉底渣的理化特性

小型垃圾热处理设备可实现就地处置,节约运输成本,目前在中国山区、丘陵地带的村镇得到广泛应用.为了解村镇小型生活垃圾热处理炉底渣的理化特性及其影响因素,对中国云南、贵州、安徽村镇实际运行的小型生活垃圾热处理设备产生的底渣进行取样,分析其热灼减率、物理组成、化学组成、晶相组成、重金属含量和浸出特性,探讨处理工艺、地域及季节...     

风险社会中突发事件的特征与处置理念探析

突发性事件由于其本身所具有突发性、紧急性、危重性、复杂性、关联性、广泛性、政治性和不确定性等特征，所以其负面性影响很大，往往可能成为激发社会矛盾、进而爆发政治、经济和社会危机的直接原因。而经济转轨、社会转型、利益群体多元化等许多不稳定的因素，对局部地区乃至全国的经济发展和社会稳定构成了潜在威胁。在这样一个具有诸多风险因素的社会，由此而引发的突发事件又有形式多元化、规模扩大化、形态群体化、影响辐射化、目标国际化等特点。所以，在现阶段，处置突发事件的理念必须适应这种风险社会的公共危机特点，做到危机缓和，未病先防；以人为本，取信于民；利益调和，治病求本。     

市场经济体制下的耕地经营制度：浅析耕地租赁制

本文分析了在市场经济体制下的耕地经营制度和存在的问题，探讨了耕地租赁制度的内容、优点及其对策。     

THROUGHFALL IN PLANTED STANDS OF FOUR SOUTHERN PINE SPECIES IN EAST TEXAS1

Throughfall was measured during 1978–79 beneath the canopies of adjacent stands of four major southern pine species, all on identical soil type and topography in the Stephen F. Austin Experimental Forest. Observations from 44 storms in a randomized network of 15, 5.08 cm PVC gages in a 0.4 ha plot of each species showed that throughfall expressed as percent of storm precipitation, is greatest under longleaf pine and least under loblolly pine; throughfall under shortleaf and slash pine did not differ significantly. Generally, through-fall decreased with storm size and intensity, with distance from the nearest tree stem, and is greater during summer half-year (May–October). Canopy drips, apparently accounting for the greater throughfall for the gage position closer to the stems, were more numerous than reported elsewhere. The 5.08 cm PVC gages proved to be acceptable substitutes for standard nonrecording gages in measuring throughfall. A network of 15 such gages was sufficient to sample throughfall data with 90 percent accuracy in each of the four southern pine plantations.     

WATER-BASED ACTIVITY INVOLVEMENT FOR RECREATION CONSUMERS AT STATE,FEDERAL, LOCAL,OR PRIVATE FACILITIES1

ABSTRACT: The water-based activity involvement of participants at state and federal and local and private facilities identified by using participation rate groups is examined. No differences between participant groups within activities based on socio-economic characteristics were found. However, groups of highly active individuals were identified at both types of properties. It is suggested that social action system variables be added to traditional social aggregate variables to assist the understanding of leisure involvement.     

基于GM(1,1)模型的铁路行车事故预测

铁路行车事故的发生具有偶然性 ,但可利用预测理论的方法加以预测。笔者简述了灰色理论中GM(1,1)预测模型的建模过程和精度检验的方法及步骤 ,在某铁路分局 1995～ 2 0 0 2年间的铁路行车事故统计的基础上 ,应用GM(1,1)预测模型预测了该铁路分局 2 0 0 4年的铁路行车事故发生趋势 ,经精度检验表明 ,模型的精度等级合格 ,其预测结果为铁路行车事故的防范和降低事故损失提供了指导和科学依据。     

家庭装修与选材

装修材料的正确选择是完善空间环境设计的主要要素,本文根据目前市场上一些流行的装修材料的特性进行全方位的分析,力求根据空间自身的特点,合理的运用材料本身的设计语言,创造出更加适用、丰富、绿色的可延展性的意境空间。