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81.
82.
Palladium nanoparticles were deposited on the amine-grafted glass fiber mat (GFM-NH2) catalyst support by a conventional impregnation process followed by the borohydride reduction in aqueous solution at room temperature to create the designed Pd/GFM-NH2 catalyst. By the use of large size glass fiber mat without nano/mesopores as the catalyst support, the internal mass transfer limitations due to the existence of nano/mesopores on the catalyst support were eliminated and the Pd/GFM-NH2 catalyst could be easily separated from treated water due to the large size of the catalyst support. Batch experiments demonstrate its good catalytic reduction performance of Cr(VI) with formic acid as the reducing agent. It also demonstrated an efficient Cr(VI) removal and stability in a lab-prepared, packed fixed-bed tube reactor for the continuous treatment of Cr(VI)-containing water. Thus, it has a good potential for the catalytic reduction of Cr(VI) in the water treatment practice. 相似文献
83.
Falls pose an important problem for older adults. Balance training is one of the main prevention strategies, but there is a lack of objective measurement methods that would allow the effectiveness of the treatments employed to be assessed. This study aimed to analyse the relationship between posturographic parameters and risk factors associated with falling, including the fear of falling (FoF). Forty-one healthy community-dwelling older adults were surveyed on their perception of problems considered to be fall risk factors. Balance measurement with posturography was performed. The relationships between risk factors and falls and risk factors and posturography were analysed by means of cross-tabulation and logistic regression, respectively. Experimental results showed a significant relationship between some of the posturographic parameters and various fall risk factors. Stability limits were related to FoF, and results from the Romberg test with eyes closed with and without foam correlated with problems in kneeling/crouching. The results from the Romberg test with eyes closed and foam correlated with osteoarthritis. Equations were developed to estimate the probability of having such problems. In conclusion, posturography is useful for the estimation of fall risk conditions in relation to three important fall risk factors (FoF, osteoarthritis and problems in kneeling/crouching), and it could be used for targeting, training and studying progress after the use of different treatments.Relevance to industryPosturography can be used as an assessment tool to analyse the effects of those treatments aimed at preventing falls. Furthermore, the equations derived from our results can be used along with posturographic variables to assess patient progress. 相似文献
84.
Declining phosphorus as a potential driver for the onset of Didymosphenia geminata mats in North American rivers 下载免费PDF全文
Lisa A. Kunza Carole‐Anne Gillis Justin N. Murdock Jonathan M. O'Brien 《河流研究与利用》2018,34(8):1105-1110
Didymosphenia geminata is a stalk‐forming diatom capable of creating thick benthic mats in low‐nutrient streams. There are two hypotheses to explain the rapid worldwide increase in occurrence of nuisance D. geminata mats: (a) Cells are spread among rivers and across broad ecoregions through natural and anthropogenic vectors, or (2) pre‐existing D. geminata populations are forming mats in response to changing environmental conditions within the habitat. Low phosphorus (P) concentrations are a major trigger for stalk production by D. geminata cells. Although the environmental change hypothesis is gaining support among researchers, long‐term data sets demonstrating declining P concentrations prior to reported mat formation have been essentially absent from the literature. Here, we present long‐term datasets for two case studies for which long‐term P and D. geminata data coincide: the Matapedia River in Eastern Canada and the Kootenai River below Libby Dam in Montana, United States. Both rivers had declining P levels over time. However, there was a 2‐ and 20‐year lag time, respectively, between mat development and reaching the previously proposed average 2 μg/L soluble reactive P threshold for development. Although the Matapedia River provides some support of the environmental change hypothesis, the Kootenai River data set suggests other environmental factors may play a role in mat development. The data presented do not rule out the environmental change hypothesis but do suggest there may be conditions in addition to low P that must be met for mats to form and the environmental change hypothesis can likely be refined to include more parameters to better understand and mitigate the influence of mats. 相似文献
85.
简述了传统护坡治理中存在的问题,介绍了生态袋护坡、三维植被网护坡及稻草垫生物护坡在辽宁省河道治理中的应用,结合工程实例阐述了三种护坡形式的特点及实际应用中应注意的问题。 相似文献
86.
河道的回水地带常年受河道水流迎流顶冲影响,岸坡冲刷严重易崩塌,影响岸坡安全。以涡河县义门镇涡河左堤崩岸段应急加固工程为例,采用吨袋垫坡+膜袋自密实混凝土护坡技术对崩岸段进行加固处理有效解决了水下护岸边坡因水流冲刷引起的变形与坍塌问题,效果良好,可为类似工程施工提供参考。 相似文献
87.
以工业废渣为主要原料研制了低温一次快烧生料无光釉,分析探讨了废渣无光釉的化学组成和烧成条件,该釉不仅适于一次低温快烧工艺,而且可显著降低釉料成本,在墙地砖生产中有较大应用价值。 相似文献
88.
现代设计技术在机械设计中的应用 总被引:2,自引:0,他引:2
董俊华 《河南机电高等专科学校学报》2007,15(1):79-82
机械设计是机械工程的重要组成部分,随着科技的发展,现代设计技术与机械设计技术相结合,设计新手段、新方法、新技术不断地涌现.文中从数学基础知识、IT技术、新概念等方面入手,介绍了多种现代设计技术. 相似文献
89.
采用与传统干法生产工艺不同的湿法造纸工艺,以非金属矿物纤维海泡石为主要纤维原料配加玻璃纤维、陶瓷纤维、有机纤维生产净化器衬垫.结果表明:以非金属矿物纤维海泡石为主要纤维原料制作的净化器衬垫具有较好的物理性能. 相似文献
90.
China has been experiencing a rapid increase in battery-powered personal transportation since the late 1990s due to the strong growth of the electric bike and scooter (i.e. e-bike) market. Annual sales in China reached 17 million bikes year−1 in 2006. E-bike growth has been in part due to improvements in rechargeable valve-regulated lead-acid (VRLA) battery technology, the primary battery type for e-bikes. Further improvements in technology and a transition from VRLA to lithium-ion (Li-ion) batteries will impact the future market growth of this transportation mode in China and abroad. 相似文献