重庆市都市功能核心区秋季大气污染物时空分布特征

为研究重庆市都市功能核心区大气污染物浓度水平及变化规律,统计分析了2014年9月至2014年11月5个监测站(解放碑、高家花园、杨家坪、新山村和南坪)24 h连续监测PM_(2.5)、PM_(10)、SO_2、NO_2、CO和O_3浓度数据.结果表明,观测期间,大气颗粒物污染严重,5个站点PM2.5日均浓度超标率分别为30.8%、37.4%、38.5%、37.4%和31.9%,5个站点PM10日均浓度超标率分别为23.1%、22.0%、18.7%、19.8%和19.8%;重庆市都市功能核心区细颗粒物(PM_(2.5))污染严重,5个站点PM2.5占PM10比例分别为60.2%、64.6%、64.1%、75.4%和62.8%;PM_(2.5)、PM_(10)、NO_2和CO早晚出现高峰值;SO_2和O_3浓度日变化曲线呈现单峰型,峰值分别出现在中午和午后;降水量、气温和水汽压与PM_(2.5)、PM_(10)、SO_2和NO_2呈显著负相关;相对湿度与O_3呈显著负相关,气温、水汽压和风速与O_3呈显著正相关;CO与相对湿度呈显著正相关;风向也影响着大气污染物浓度的时空分布,南偏西、南偏东和东北偏北风利于PM_(2.5)、PM_(10)、SO_2、NO_2和CO浓度积累,西北风利于PM_(2.5)、PM_(10)、SO_2、NO_2和CO扩散;但西北风控制下利于O_3浓度积累.     

带压作业闸板防喷器胶芯失效机理研究

针对带压作业过程中闸板防喷器胶芯易失效的问题,以现场使用的带压作业闸板防喷器胶芯为研究对象,通过实验确定了橡胶基体的本构关系,利用ABAQUS软件对比研究了4种不同井筒压力对胶芯的疲劳失效与密封失效的影响。结果表明:分析结果与现场应用胶芯的失效位置相符,验证了分析的正确性;胶芯的疲劳失效位置集中在橡胶基体与闸板上下部的4个尖角接触区域,上部区域失效严重;井筒压力的大小影响橡胶基体密封面上的接触应力分布,但对耐磨块密封面上接触应力分布影响不显著。建议在橡胶基体与闸板上下部的4个尖角区域补强以增加胶芯寿命。     

More than good intentions: the role of conditions in personal transportation behaviour

Engaging individuals in pro-environmental behaviours is critical to addressing today’s environmental challenges. This study examines how conditions – or an individual’s context – influence action. Through semi-structured narrative interviews and document analysis, we examined the influence of conditions in five individual cases involving attempted change in personal transportation behaviour. The cases, studied over the course of one year, are derived from participants in a sustainability institute, representing a range of attempted behaviours, and highlight numerous potential barriers to desired pro-environmental behaviours. We found that the degree of engagement with sustainable transportation primarily was influenced by the amount and intensity of supportive conditions relative to barriers. Participants who successfully engaged in their desired transportation-related pro-environmental behaviours experienced physical, social, and learning conditions that promoted competence and satisfaction. We discuss the implications for designing interventions that encourage pro-environmental behaviours.     

Sedimentary record of PAHs in the Liangtan River and its relation to socioeconomic development of Chongqing, Southwest China

Concentrations of polycyclic aromatic hydrocarbons (PAHs) were detected in sediment cores and surface sediment samples from the Liangtan River of Chongqing, Southwest China. The total concentration of 16 PAHs ranged from 69 to 6251 ng g⁻¹. The spatial distribution of the PAHs reflects the intensity and scope of human activity in the catchment. A historical record of PAH contamination was reconstructed using a sediment core from a background segment of the river. The characteristic changes of concentrations, fluxes and patterns of 16 PAHs over the past ∼90 years were captured in detail. An obvious peak of PAH concentration and flux was found in the 1940s, i.e., during war time, and then a sharp increase was observed from the early 1980s to the present. The maximum concentration and flux reached 1260 ng g⁻¹ and 470 ng cm⁻² year⁻¹, respectively. The sharp increase was attributed to the contribution of pyrogenic sources of PAHs. The population, length of highways and energy consumption of Chongqing, as indexes of socioeconomic development, were positively correlated with PAH input in the sediment core from the 1950s to the present. The results clearly show that the local socioeconomic development in the last decades remarkably aggravated the environmental load of sedimentary PAHs.     

VA菌根真菌对玉米生长及根际土壤微生态环境的影响

用两种不同的VA菌根真菌Glomus mosseae和Glomuscaledonium接种玉米进行盆栽试验。结果表明,两种菌株均能侵染玉米,促进玉米生长．其中以Glomus caledonium的侵染率和作用较为明显。接种后,根区土壤中的细菌、放线菌、固氮菌的数量和微生物生物量明显增加,但真菌的数量则稍有下降。此外．菌根的形成也改善了根区土壤的微生态环境,为下一造作物的生长积累了养分基础。     

泉州湾沉积物柱状样中有机氯农药的垂直分布特征

用GC-ECD内标法测定了泉州湾沉积物柱样中有机氯农药的含量.通过研究有机氯农药在沉积物柱样中的垂直分布特征,探讨了有机氯农药在泉州湾的污染历史.该柱样中HCHs和DDTs的含量分别为(0.00～5.61)×10-9、(1.18～50.65)×10-9.研究表明该区沉积物未受到HCHs的明显污染,但已受到DDTs的轻微污染.有机氯农药的垂直变化基本反映了它在我国及福建的生产使用历史.在近年泉州湾仍有新的DDT输入.     

官厅水库沉积物柱状样中有机氯农药的垂直分布特征

以气相色谱-电子捕获检测器(GC-ECD)内标法定量测定了官厅水库永1008横断面沉积物柱状样品中有机氯农药的含量,以便对自蓄水以来官厅水库沉积物中有机氯农药的历史沉积变化特征和可能的来源进行初步探讨。定量测定结果以HCHs,DDTs和有机氯农药总量(OCPs)计算,样品中w(HCHs),w(DDTs)和w(OCPs)分别为2 0～25 7,0 3～1 9和3 2～28 3ng g;据永1008横断面沉积图推算,官厅水库永1008横断面沉积物中有机氯农药的主要来源是上游地区的农业生产和工业排污,集中在1980—1991年。因此,在未来库区的清淤疏浚工程中,应特别注意不同层次底泥中有机氯农药的再悬浮与释放,以及清淤后底泥的防污处置。      

A 50-year sedimentary record of heavy metals and their chemical speciations in the Shuangtaizi River estuary (China): implications for pollution and biodegradation

Two parallel sediment cores collected from tidal flat located in the Shuangtaizi River estuary were analyzed for heavy metal concentrations and chemical speciations. Based on the ¹³⁷Cs activity profile, mean sedimentation rate at the sampling site during the past 50 years was estimated to be 1.3 cm·a^-1. Correlation analyses show that almost all the metals are associated with each other, suggesting that these metals might be derived from same sources and/or affected by same geochemical processes. Influence of total organic carbon (TOC) content on the concentrations of Cr, Ni, Cu and Cd is evident. Silt and clay contents, instead of sand content, play an important role in the distribution of these metals. The dominant binding phases for most of the metals (except for Cd) are the residual. The relative decrease of the residual fraction of Cd and Pb in the upper 66 cm of the core is striking. The distribution of chemical fraction confirms that the residual fractions of these metals have a natural origin, while only the non-residual fractions of Cd and Pb increased upward the core due to pollution in the past five decades. Pollution assessment on these heavy metals based on Index of Geoaccumulation (I_geo) also demonstrates that most of the metals are unpolluted. The weak pollution as observed in the sediments is perhaps related to a local plant, the Suaeda heteroptera Kitag, which may have played a significant role in the biodegradation of these metals and the metal distribution in the estuary.     

湖泊沉积柱中的高溴联苯醚及其在环境中的降解

采用GC/MS方法分析了5个内陆湖泊(巢湖、滇池、红枫湖、青海湖和四海龙湾)钻孔沉积物中HB-PBDEs(高溴联苯醚,包括九溴和十溴的联苯醚)的垂直分布状况,并对它们的组成特征及其在环境中的降解进行了分析.结果显示,5个内陆湖泊表层沉积物中有机碳归一化后的w(ΣHB-PBDEs)为17.5～977.9 ng/g,其中滇池、红枫湖和巢湖HB-PBDEs的污染相对较为严重;与国内外其他研究相比,我国内陆湖泊沉积物中BDE-209的污染状况相对较轻.沉积物中HB-PBDEs的组成特征显示,BDE-209不但在大气传输过程中发生了明显降解,而且在进入湖泊沉积物后也发生了明显降解.由于BDE-209在不同环境介质中都可发生降解,并且降解产物为毒性更大的低溴代单体,因此进一步研究BDE-209在环境中的降解具有重要意义.      

Multiple dimensions of human resource development and organizational performance

Building on strategic human resource management literature, this study investigates the effects of various human resource development (HRD) dimensions on organizational performance. We identify four distinct dimensions of HRD that reflect either quantitative or qualitative approaches from either managerial or employee perspectives. Furthermore, we propose that HRD affects organizational performance by shaping employee outcomes, a prevailing but rarely tested assumption. Multi‐source data collected from 207 manufacturing companies at three time points over a 5‐year period largely support our theoretical propositions. A series of structural path analyses confirm that HRD improves employee commitment and competence, which in turn determine the financial performance of the organization. The quantitative dimensions of HRD (resource investment in HRD) predict only employee commitment. By contrast, the qualitative dimensions of HRD (management support for, and perceived benefits of, HRD) enhance both employee commitment and competence. Our analysis also demonstrates synergistic interactions between the quantitative and qualitative dimensions of HRD in predicting employee outcomes. This study elaborates the distinct values of different dimensions of HRD and highlights the significance of employee outcomes as the mediating mechanism between HRD and firm performance. Copyright © 2014 John Wiley & Sons, Ltd.