石墨相氮化碳光催化剂的制备、改性及其在水处理中的应用

作为典型的非金属半导体光催化剂,类石墨相氮化碳(g-C3N4)由于具有物理化学性质稳定、能带结构适宜、制备成本低廉等优势,近年来受到广泛关注.本文综述了石墨相氮化碳的基本结构特性、常用制备方法以及结构改性策略,对其在水处理中的应用进行了总结,并对g-C3N4未来的发展趋势进行了展望,以期为氮化碳新材料开发及其在水处理方...     

Factors influencing the acceptance of nature conservation measures--a qualitative study in Switzerland

Landscapes fulfil a multitude of ecological and social functions. Due to the fact that both traditional and everyday landscapes today face many different threats, regulatory measures have been undertaken in many countries to protect and further sustainable landscape development. They include legislation as well as economic incentives. In recent years, however, it has become clear that just to have a few laws and to spend money on subsidies is not enough. Factors other than legislation are also essential to further the sustainable development of landscapes. One of the basic factors affecting the success or failure of landscape conservation measures is public acceptance of these measures. Our project took this as its starting point. The objective was to determine which conditions and factors influence acceptance positively or negatively. To this end 22 Swiss who are directly affected by nature conservation measures, in particular by mire landscape and dry meadow conservation measures, were interviewed using qualitative interview techniques. It is shown that perception, communication, and possibilities to participate are the most decisive driving factors influencing the formation of a long-lasting acceptance. Furthermore, acceptance may be based mainly on economic criteria, on usefulness, on ecological or even aesthetic aspects. It can be shown that not all of these motivations lead to a long-lasting acceptance. Ecologically based acceptance seems the most promising because it is founded on general convictions. Economic incentives--though important--seem to generate only superficial acceptance and do not seem to be as important as is usually assumed.     

An Interpretive Study of Yosemite National Park Visitors’ Perspectives Toward Alternative Transportation in Yosemite Valley

The National Park Service (NPS) is increasingly focusing on alternative transportation systems in national parks to address environmental and social problems arising from a historical reliance on personal automobiles as the primary means of visitor access. Despite the potential advantages, alternative transportation may require a reorientation in the way that Americans have experienced national parks since the advent of auto-tourism in the early twentieth century. Little research exists, however, on visitor perspectives towards alternative transportation or the rationale underlying their perspectives. It remains unclear how transportation systems affect visitors’ experiences of the park landscape or the factors influencing their travel behavior in the parks. This report presents an interpretive study of visitor perspectives toward transportation management in the Yosemite Valley area of Yosemite National Park, California. Qualitative analysis of 160 semi-structured interviews identified individual psychological factors as well as situational influences that affect visitors’ behavior and perspectives. Individual psychological factors include perceived freedom, environmental values and beliefs, prior experience with Yosemite National Park and other national parks, prior experience with alternative transportation in national parks, and sensitivity to subjective perceptions of crowding. Situational factors included convenience, access, and flexibility of travel modes, as well as type of visit, type of group, and park use level. Interpretive communication designed to encourage voluntary visitor use of alternative transportation should focus on these psychological and situational factors. Although challenges remain, the results of this study suggest approaches for shaping the way Americans visit and experience their national parks to encourage environmental sustainability.     

低温下废铁屑对厌氧氨氧化系统的影响

考察了在低温条件下(<20℃)废铁屑及其投加方式对厌氧氨氧化反应器脱氮性能和微生物群落的影响.结果表明,当废铁屑投加量为10g/L时,直接(R2)和间接(R3)投加方式均会对厌氧氨氧化反应造成短期抑制,总氮去除率分别降低4.7%和3.4%;30d连续运行后,2组反应器总氮去除率均提升至70%左右;反应器稳定运行阶段,R2的R_s(NO₂^--N与NH₄⁺-N去除量之比)和R_p(NO₃^--N生成量与NH₄⁺-N去除量之比)为1.57和0.22, R3的R_s和R_p为1.49和0.23,比R2更接近厌氧氨氧化反应理论值.废铁屑在水中发生腐蚀,降低DO并提高pH值,且R2,R3污泥中铁含量分别为对照组的1.64倍和1.93倍,废铁屑不仅改善了厌氧氨氧菌的生境,还满足了其对铁元素的需求.高通量测序结果显示,在20~50d的运行过程中, R1,R2,R3中优势厌氧氨氧化菌属Candidatus_Kuenenia的相对丰度分别增加-1.05%,0.14%和0.96%,废铁屑的投加促进了厌氧氨氧化菌在低温下的生长,且间接投加促进效果更为显著.     

Hydrothermal-treated Pt/Al2O3 as an excellent catalyst for toluene total oxidation

The preparation of highly active supported noble metal catalysts with a low noble metal loading has always been the ultimate goal of researchers working on catalysis. Hydrothermally treated Pt/Al₂O₃ (Pt/Al₂O₃-H) exhibits better catalytic activity than that (Pt/Al₂O₃-C) treated via the conventional calcination approach. At the high space velocity of 100,000 mL/(g∙hr), the temperature that correspond to 50% toluene conversion (T₅₀) of Pt/Al₂O₃-H is 115°C lower than that of Pt/Al₂O₃-C, and the turnover frequency (TOF) value can reach 0.0756 sec⁻¹. The mechanism by which the hydrothermal approach enhances Pt/Al₂O₃ activity has been investigated. The structure associated with the high catalytic activity of Pt nanoparticles (NPs) can be retained via hydrothermal treatment. Furthermore, the support is transformed to AlO(OH) with numerous surface hydroxyl groups, which in turn can facilitate the adsorption of toluene. And the synergistic effects of Pt NPs and AlO(OH) increases the contents of Pt in oxidation state and active oxygen, which are beneficial for toluene oxidation.     

土壤环境汞污染现状及其影响因素研究进展

土壤重金属污染导致土壤环境质量显著降低,影响食品安全、水源水质和空气质量等,严重威胁人类的生存和发展。汞（Hg）作为一种全球性的重金属污染物,广泛分布于多种环境介质中,其中土壤是全球汞最大的储存库。土壤中的汞可通过多种暴露途径进入人体,危害人类健康。伴随着全球气候变暖和人为活动加剧,全球土壤汞污染问题日益严重。然而,目前有关土壤汞污染的基础数据较为缺乏,大范围的土壤汞污染空间分布特征分析相对较少,对于土壤汞污染主控因子的分析方法缺乏系统的阐述。因此,本文基于文献调研的方法,分析了全球的土壤汞污染分布特征,发现全球土壤汞污染主要集中在矿区及工业聚集区,阐述了人为因素、气候条件和土壤环境因素等对土壤汞含量变化的影响,并总结了可应用于土壤汞污染主控因子分析的常用方法及其优缺点。同时,本文对未来土壤汞污染调查和研究进行了3方面的展望,以期为更加科学合理的解决土壤汞污染问题做出贡献。     

河豚毒素检测技术研究进展

对检测河豚毒素的主要方法包括生物检测方法、理化检测方法、免疫学方法、传感器方法进行了介绍,并对目前检测方法的优缺点进行比较分析。小鼠测定法是河豚毒素检测的标准方法;理化检测法方法准确,但是对设备要求高,前处理严格;免疫学方法费用较高;传感器方法是新方法,还有待进一步规范。各种检测方法都有其优缺点,河豚毒素检测时应根据要求选择方法。     

Cultivating hybrid collectives: research methods for enacting community food economies in Australia and the Philippines

Across the globe, groups are experimenting with initiatives to create alternatives to the dominant food system. What role might research play in helping to strengthen and multiply these initiatives? In this paper we discuss two research projects in Australia and the Philippines in which we have cultivated hybrid collectives of academic researchers, lay researchers and various non-human others with the intention of enacting community food economies. We feature three critical interactions in the “hybrid collective research method”: gathering, which brings together those who share concerns about community food economies; reassembling, in which material gathered is deliberatively rebundled to amplify particular insights; and translating, by which reassembled ideas are taken up by other collectives so they may continue to “do work”. We argue that in a climate-changing world, the hybrid collective research method fosters opportunities for a range of human and non-human participants to act in concert to build community food economies.     

Design principles in commons science: A response to “Ostrom,Hardin and the commons” (Araral)

Within the literature on common-pool resource management, one of the primary methodologies used is the meta-analysis of case studies, due to the difficulties of otherwise producing large-n datasets that span multiple systems. In this paper we respond to a critique of a previous meta-analysis that we have conducted, in which we evaluated Elinor Ostrom’s institutional design principles. Within our response we correct what we perceive to be factual errors contained in this critique, but more importantly we try to use this opportunity to re-evaluate our own work and expand this evaluation to the seminal work of Elinor Ostrom and the research program on common-pool resource management. We find that the original critique highlighted several important points, primarily the challenge of unpacking complex variable relationships and the conflation of diverse outcomes, and we discuss how these are challenges for the larger commons field. We conclude with some comments on how to move forward to confront these challenges.     

The Subjective Rating Scales for Measurement of Mental Workload—Thurstonian Scaling

Subjective rating scales for measuring work demands and individual capabilities to cope with work requirements were developed using the Thurstonian procedure. The scales measure six dimensions of mental workload: mental difficulties, feeling of responsibility, awareness of risk, interpersonal conflicts, monotony, and time pressure. Individual scale results make it possible to assess the level of mental workload understood as a relation between the subjective rating of work demands and individual capabilities in each of the six dimensions. Two versions of scales were prepared: classic and modified ones. To assess the level of reliability of the particular scales, 481 participants were examined twice at a 1-month interval. A procedure to prepare scales for the measurement of other dimensions of mental workload is also presented.