液桥凝聚用于办公废纸脱墨的研究

研究了混合办公废纸脱墨的选择性凝聚技术，在废纸浆中添加分散在水中并不与水相溶的长链烷作凝聚剂，这些凝聚剂选择性地将印刷墨粉通过液桥连结在一起，且形成大颗粒的球形聚团，再分选脱除。研究表明只需要加入占纸重量4％的廉价长链烷，即可获得95％以上的脱墨率。因此在混合办公废纸脱墨时加入凝聚剂进行液桥凝聚，可降低脱墨浆中的尘埃度并增加产品的白度。     

Gas/particle partitioning of polycyclic aromatic hydrocarbons in coastal atmosphere of the north Yellow Sea, China

Samples of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) were collected at three sampling stations (Xiaomai Island, Laohutan, and Zhangzi Island) in the north Yellow Sea, China during November 2008 and September 2009 to study their atmospheric transport potential and the gas/particle distributions. The composition of PAHs was dominated by gaseous compounds. The percentages of the particle-phase PAHs to the total concentrations were found to be higher during the heating period than the non-heating period. The ratios of naphthalene and acenaphthene to phenanthrene, chrysene and dibenzo(a,h)anthracene showed an increasing trend from Xiaomai Island to Zhangzi Island, which can be called as the local atmospheric distillation of PAHs. Gas/particle partitioning coefficients (K _p) and their relationship with the sub-cooled liquid vapor pressures (pº_L) of PAHs were investigated. The regressions of logK _p versus logpº_L gave significant correlations for all samples of the three sites with r ² values in the range 0.56–0.66 (p?<?0.01). Both Junge–Pankow adsorption model and octanol–air partition coefficient absorption model tended to underestimate the sorption for most PAHs, but the absorption model appeared to be more suitable for predicting the particle fraction of PAHs than the Junge–Pankow model.     

基于超标风险改进的加拿大水质指数及其应用

将三角模糊数和超标风险度引入加拿大水质指数(CCME-WQI),建立了能够反映超标风险的改进型CCMEWQI。改进后的CCME-WQI通过计算水质指标的超标隶属度与超标风险,可实现对水质不确定性与超标风险的综合考量。在此基础上,评价了重庆市某水库2016—2019年水质状况。结果显示:改进后的CCME-WQI的评价结果较仅反映最差指标类别的单因子评价法的评价结果更为全面、客观。基于超标风险改进的CCME-WQI考虑了即将超标但尚未超标的水质因子存在的风险,在结果显示上比改进前的CCME-WQI更为全面、严格,更适用于评价一段时间内的水体污染程度和超标状态。     

A novel speed model for safety evaluation of freeway alignment in Euclidean 3D space

Objective: Operating speed is a critical indicator to evaluate consistency of road alignment and safety. Although extensive studies have been conducted on developing operating speed models, few researchers have considered the interactive influence of horizontal and vertical alignment in 3D space. The purpose of this study is to develop a speed model based on 3D alignment in Euclidean space rather than traditional horizontal and vertical alignment.

Methods: According to the curve theory of differential geometry, a novel method to estimate operating speed is proposed in our study using 3D space curvature instead of traditional horizontal or vertical parameters to describe the spatial geometric properties for a freeway alignment. Speeds of 54 different alignment segments are observed to develop the speed model. Several observing sites of each segment are selected beforehand, and the speeds of more than 300 vehicles in each site are observed. Space curvature is used as an important index to estimate operating speed.

Results: The findings of this study indicated that both horizontal alignment and vertical alignment contribute to space curvature. Space curvature mainly affects direction control operating performance. However, vehicles overcome the effects of gravity along the vertical alignment in the z direction. Results indicate that operating speed exponentially declines with space curvature and that quadratic parabola decline with vertical grade.

Conclusions: It can be concluded that there is a clear correlation between velocity and spatial curvature, which is proved by variance analysis. The estimation results of the speed models are reliable as tested using a real engineering example. The study would provide a scientific basis for safety evaluation of freeway alignment.     

土默川平原不同盐渍化程度土壤微生物生态特征研究

为了探究土壤微生物对不同盐渍化程度土壤质量的响应,以土默川平原盐渍化土壤为研究对象,采用平板稀释法和氯仿熏蒸法分析了土默川平原不同盐渍化程度土壤微生物区系、结构组成、微生物生物量碳及微生物熵的季节动态特征。结果表明:土默川平原土壤微生物总量较少,变化范围在2.89×105～38.77×106个g-1干土之间,其中细菌占绝对优势,占微生物总数的93.14%～99.53%。随着盐渍化程度的加重,土壤细菌、真菌和放线菌数量及微生物总数呈显著下降的趋势,其中细菌数量在轻度、中度、重度盐渍化程度下的比值为1∶0.83∶0.60,真菌为1∶0.70∶0.30,放线菌为1∶0.66∶0.56,微生物总数为1∶0.84∶0.61;除真菌外,不同盐渍化程度土壤细菌、放线菌及微生物总数呈极显著的季节性变化。土壤种群数量占微生物总数的比例大小为细菌>放线菌>真菌。不同盐渍化程度土壤微生物量碳和微生物熵表现为:轻度盐渍化>中度盐渍化>重度盐渍化;不同盐渍化程度土壤微生物生物量碳和微生物熵的季节动态呈单峰上凸式曲线变化,在8月份达最高值,其值为0.15 g kg-1、3.44%。因此,土默川平原不同盐渍化程度土壤微生物区系特征差异显著,土壤盐分含量是影响该地区微生物生长的主要因素。     

热固性树脂对芳纶复合材制防弹性能的影响

采用环氧树脂对酚醛树脂进行改性,树脂的粘结强度明显提高,当环氧树脂含量保持在6％时,防弹复合板的防弹性能最优,复合板的安全裕度更高。而当树脂固含量在15％-25％,复合板的最大粘结力为37．8-40．1N,其中,当树脂固含量为20％时,防弹复合板的防弹性能最优。同时研究了增塑剂对复合板防弹性能的影响,结果显示,当增塑剂含量为15％时,防弹复合板的防弹性能最优。     

粉煤灰复合材料砖的研制

提出了在常温下以粉煤灰为主要原料，研制高强度复合材料的方法。探讨了物料的成分配比、混料、成型和干燥的过程参数，并确定了材料的各项性能指标。     

水中痕量酚类的分离富集及色谱分析

本文综述了近十年来水中重要有机污柒物—酚类化合物的分离富集技术,以及色谱法(GC法和HPLC法)分析。     

居民风险承受能力评价模型及实证分析

提高公众的风险承受能力对防灾减灾战略的成功有着重要的作用。在定义了风险承受能力地内涵的基础上,建立风险承受能力的评价指标体系,构建了风险承受能力各个因子的影响模型。以安徽省沙河集水库下游居民为调查对象,进行了风险承受能力大小的调查。研究表明风险承受能力的主要影响因素包括风险认识、安全倾向、个人风险心理和个人避险能力,它们之间是一个相互制约的循环模型,其制约的关系可以使个体的安全倾向、风险认识、风险心理不致过高也不致过低,有利于风险承受能力的提高。