粉煤灰制备聚硅酸盐絮凝剂的研究进展

介绍了粉煤灰的现状和主要化学成分及性质,综述了高效提取粉煤灰中硅、铝和铁的方法,以及利用提取物质制备聚硅酸盐絮凝剂的方法、条件和水处理效果;重点分析了粉煤灰的物化改性的方法、原理和效果,总结了粉煤灰制备絮凝剂的工艺和方法,对如何更高效提取粉煤灰中有用物质和制备更优越絮凝性能的絮凝剂提出了建议.     

Do Colored Photographs Affect Willingness to Pay Responses for Endangered Species Conservation?

The NOAA panel suggested that use of photographs should be pre-tested to explore their effects on subjects (Arrow et al. 1993). For this paper, a modification to the test suggested by the NOAA Panel was made. We tested whether use of colored, as opposed to black and white (B & W), photographs influence respondents’ valuation of the environmental commodity in question. The context of the test is a CVM study valuing the benefits from protecting the national bird. This was performed using two drop-off surveys that were identical except for the color of the photographs incorporated in the survey instrument. The dichotomous choice logit equations were statistically different between the two treatments of the questionnaire, indicating the significant effect of colored photographs on the respondents’ WTP. The findings support the NOAA Panel recommendation of careful pre-testing and scrutiny of the photographs integrated in the questionnaire since ‘packaging’ of the environmental good (i.e., endangered species protection) matters in valuing benefits associated with it. Since colored photographs are found to be value-enhancing, to simply use B & W photos as an attempt to reduce cost associated with implementing the contingent valuation (CV) survey, especially when limited research money is involved, would result to lower the estimated value of the environmental good.     

非对称成本信息下的网络规制定价与进入决策

本文分析了电信产业中拥有本地市话网络的在位者在下游市场（长途电话网络）面临潜在进入者的竞争的两厂商模型。两个厂商关于成本的信息是非对称的,潜在进入者进入市场的决策将会影响下游市场的市场结构,即下游市场竞争结构不是外生的。本文认为,规制者基于社会福利最大化所设计的零售和接入价格机制,在潜在进入者的成本是私有信息的情况下,对进入决策乃至市场结构有很大的影响。     

牧民参与草原社区治理决策意愿及影响因素基于内蒙古406户牧民的两阶段实证

[目的]文章通过构建牧民参与草原社区治理的"改变—参与"两阶段决策分析框架,基于内蒙古406户牧民的调研数据,实证探究两阶段决策意愿及影响因素,以期为牧区试点和实践草原社区治理提供有益的理论参考。[方法]采用描述性统计分析方法和Probit模型进行实证分析。[结果]牧民参与草原社区治理的决策意愿总体较高,78.32%的牧民在第一阶段愿意改变现有草原治理模式,91.16%的牧民在第二阶段愿意参与草原社区治理;牧民改变现有草原治理模式意愿受年龄、经营草场面积的负向影响,受减畜意愿、草原植被认知、草场生态压力认知、社会网络和协作治理认同的正向影响;牧民参与草原社区治理意愿与年龄、经营草场面积和养殖规模的负相关,与减畜意愿、社会网络、社会信任、社会规范、草场生态压力认知和协作治理认同的正相关。[结论]开展草原社区治理试点或实践牧区已具备较好的群众基础,牧民参与草原社区治理两阶段决策意愿均受多种因素影响,且两者间的影响因素存在差异。     

城乡养老保险统筹是否影响子女经济支持？——基于CHARLS的经验分析

基于CHARLS数据，使用双重差分法评估城乡养老保险统筹对子女经济支持的影响。结果表明：城乡养老保险统筹使农村老年人收到的子女经济支持总额增加24.9%，这种提升作用主要通过降低农村老年人劳动供给时间、增加照料孙辈的时间得以实现。同时城乡养老保险统筹对子女经济支持的促进效应在与子女同住、经济支持来源于儿子的农村老年人中更加显著。鉴于此，政府应逐步提高养老保险统筹层次，有序缩小城乡居民的养老保险待遇差距。