渭南市道路移动源高分辨污染物排放清单及特征研究

应用MOVES-2014a模型并对其输入参数进行了本地化修正,计算了 2018年渭南市道路移动源污染物的排放因子和排放总量.基于渭南市路网分布和GIS信息及车流分布对污染物总排放量进行了空间和时间分配,建立了 1 km×1 km和l h分辨率的排放清单.结果表明,渭南市机动车排放CO、NMVOCs、NOx、NO2、NO...     

高海拔水电水库温室气体的排放特征——以雅鲁藏布江藏木水库为例

水电水库是大气温室气体的重要来源,在一定程度上影响着区域气候变化.然而目前关于水库温室气体排放的估算仍然存在很大的不确定性,一方面原因是缺失了世界各地山区水库的数据,另一方面原因是未将受水库影响的上下游河道考虑在内.本研究重点关注雅鲁藏布江流域水电水库——藏木水库丰枯水期CO2、CH4和N2O的溶存浓度与扩散通量的时空...     

渭南主城区道路积尘负荷及交通扬尘颗粒物排放

对渭南主城区道路积尘负荷进行了实测,并计算了2018年不同道路类型和不同车型的交通扬尘颗粒物排放量。结果表明:渭南主城区支路积尘负荷最大,为1.79g/m~2,高速积尘负荷最小,为0.05g/m~2,洒水作业能有效降低积尘负荷;渭南主城区道路交通扬尘PM_(2.5)和PM_(10)的年排放量分别为1 149.65、4 751.88t;小型客车引起的交通扬尘颗粒物排放在城市道路(包括主干道、次干道、支路)和国省道(包括国道和省道)上的分担率最高,分别为59.49%、41.46%,重型货车在高速上的分担率最高,为63.35%;城市道路交通扬尘颗粒物排放有明显的双峰日变化规律,而国省道和高速不明显。     

荒漠植物红砂研究进展

主要综述了荒漠植物红砂的分布区及其生境、解剖学特征、种子萌发及幼苗生长影响因素、组织培养、生理生态特征、繁殖及育苗、分子生物学特性等方面的研究。简要阐述了修复和重建红砂植被的必要性,并着重研究了红砂种子萌发的影响因素及育苗技术的发展现状,在此基础上指出红砂研究中的不足之处,并对今后的研究方向提出了建议。     

中国代表性滑雪场网络关注度时空演变及影响因素

基于百度指数数据,运用指数测度、空间地理分析、回归模型和地理探测器,对2011—2019年中国大陆26个代表性滑雪场网络关注度的时空演变特征及影响因素进行分析。结果表明:(1)时间演化上,网络关注度呈先增后减且逐渐平稳的规律。2015年、2016年为峰值年份,季节性差异明显,共两个波动峰值且为“南北为单,中东为双”的分布格局。(2)空间特性上,全国和地区均为先增后减特征,地区差异显著;变异程度先降后增并趋于稳定,全国分布相对稳定平衡,地区分布呈不稳定集聚特性。省区冷热区域分布总体呈“东北热—西南冷”格局,层级变化以稳定型为主。(3)滑雪场层面上,滑雪场总体偏好层级变动较大,高偏好保持稳定领先,其余层级以下降变动为主。滑雪场冷热点分级呈“北热南冷”的格局,东北、华北两个热点集聚区域演变较为稳定。(4)影响因素上,需求侧影响因素排序为滑雪消费吸引力>受教育程度>经济发展水平>信息化水平>滑雪场建设水平。供给侧的滑雪人次占比、滑雪经济贡献、客运承载力、冰雪旅游资源丰度、官方媒体建设水平解释力较强,其他因素影响并不显著。     

Material flow accounting in an Irish city-region 1992–2002

This paper aims to measure raw material inputs and waste flows in an Irish city-region in order to analyse (i) whether there was absolute dematerialisation in the particular case study over the period 1992–2002 and (ii) whether material consumption and waste generation were decoupled from economic growth and increases in disposable income over the same period. It was found that the selected material flow indicators showed no evidence of absolute dematerialisation over the given study period, although more recent evidence at the national level suggests that a decline in construction activity and extraction of non-metallic minerals has resulted in an absolute reduction in material consumption and it is likely that this will be mirrored at the system boundary level.It was found that Domestic Material Consumption (DMC) per capita and Direct Material Input (DMI) per capita increased at a faster rate than Domestic Processed Output (DPO) per capita and Direct Material Output (DMO) per capita between 1992 and 2002, which indicates relative decoupling of consumption from waste generation. In addition, it was found that there was relative decoupling of consumption and waste generation from disposable income growth over the study period. Finally, it was found that average DMC and DMI figures for the selected case study were lower than the national averages but broadly similar to results for other city-regions in the European Union (EU). On a methodological note, it was concluded that material flow accounting (MFA) for city-regions in Ireland is constrained due to a lack of disaggregated data for material flows, with the exception of local waste data, and it is recommended that bottom-up analysis should be used to complement disaggregated top-down data.     

狐尾藻在不同营养底泥腐解过程中胡敏酸的变化

采用平行因子分析方法,结合紫外吸收光谱、三维荧光光谱以及傅里叶变换红外光谱技术,研究了沉水植物狐尾藻在低、中、高营养底泥腐解过程中胡敏酸（HA）的变化,进一步揭示了不同营养底泥对沉水植物腐解的影响机制.结果表明,底泥营养水平越高,狐尾藻腐解得越快（P<0.05）,释放出更多的溶解性有机碳（DOC）、溶解性总氮（DTN）、溶解性总磷（DTP）和腐殖质;底泥营养程度与HA的疏水性、分子复杂性、分子量大小呈正相关（P<0.05）;荧光鉴别出不同营养底泥HA都含有1种类蛋白质组分C2和2种类富里酸组分C1、C3,且类富里酸组分和类蛋白质组分在不同腐解条件下具有相似的组分特征;不同营养底泥不同时间提取的HA红外图谱较为相似,表明不同腐解条件不同时间提取的HA含有相似的官能团,狐尾藻腐烂高营养底泥组提取的HA含有更多的芳香性物质和有机磷.采用光谱分析法对狐尾藻腐烂分解HA成分的化学结构特征进行系统的研究,可深入了解不同营养底泥对沉水植物腐解的影响机制,为湖泊水环境生态治理和修复提供理论参考.     

Biomonitoring for exposure to multiple trace elements via analysis of urine from participants in the study of metals and assisted reproductive technologies (SMART)

Humans are exposed to concentrations of multiple trace elements through a variety of background sources; many are suspected reproductive toxicants. Prior to investigating associations between trace elements and human reproductive health, potential biomarkers of exposure should be characterized by sources of variability in the population at risk. Factors influencing elemental exposure should also be identified to ensure their consideration as potential confounding variables. The principal aim of this study is to characterize sources of variability for 19 trace elements measured in urine specimens collected from 55 women and 36 male partners completing a 1st cycle of in vitro fertilization (IVF). Urine specimens were analyzed using a biomonitoring method based on inductively coupled plasma-mass spectrometry (ICP-MS). Randomly selected urine specimens (～6%) were analyzed in duplicate, and these data were used to characterize sources of variability. Nine trace elements including As, Ba, Cd, Cs, Co, Cu, Mn, Mo, and Zn, were quantified in most specimens, indicating their utility in future epidemiologic studies of trace elements exposure and IVF outcomes. With few exceptions, normalizing urine using the traditional creatinine-correction procedure, or an alternative approach based on a linear regression model, increased residual variability only slightly. Sex and race appear to be important factors to consider in epidemiologic studies conducted in this population. Urine concentrations for most elements are similar to those reported in the 2005-2006 National Health and Nutrition Examination Survey (NHANES); however, differences in others may indicate regional trends or a unique exposure history for this infertile study population.     

甘肃省旅游业发展与经济增长关系的实证研究

基于向量自回归模型(VAR)的计量分析,对甘肃省旅游业发展与经济增长的关系进行了实证分析.结果显示,甘肃省旅游业发展与经济增长间存在长期均衡的协整关系;经济增长是旅游收入提高的Granger原因,而旅游业发展不是经济增长的Granger原因;甘肃省经济增长对其旅游业发展具有正向影响;同时,旅游业收入的结构冲击对经济增长波动的影响有限.     

Decomposition of hexachlorobenzene over Al2O3 supported metal oxide catalysts

Decomposition of hexachlorobenzene (HCB) was investigated over several metal oxides (i.e., MgO, CaO, BaO, La₂O₃, CeO₂, MnO₂, Fe₂O₃, and Co₃O₄) supported on Al₂O₃, which was achieved in closed system at a temperature of 300°C. Catalysts were prepared by incipient wetness impregnation with different metal oxides loading and impregnating solvents. The decomposition efficiency of different catalysts for this reaction depends on the nature of the metal oxide used, and Al₂O₃ supported La₂O₃ was found to be the most active one. Pentachlorobenzene (PeCB), and all tetrachlorobenzene (TeCB), trichlorobenzene (TrCB), and dichlorobenzene (DCB) isomers were detected after the decomposition reaction, indicating that the decomposition was mainly a dechlorination process. The detection of all lower chlorinated benzenes suggested the complexity of decomposition and the presence of more than one dechlorination pathway.