Comparisons of microbial community structure, in eight filter media of zeolites, anthracite, shale, vermiculite, ceramic filter media, gravel, steel slag and bio-ceramic, were undertaken by analyzing the phospholipid ...Comparisons of microbial community structure, in eight filter media of zeolites, anthracite, shale, vermiculite, ceramic filter media, gravel, steel slag and bio-ceramic, were undertaken by analyzing the phospholipid fatty acid （PLFA） composition. A total of 20 fatty acids in the range of C18to C20 were determined but only 13 PLFAs were detected in steel slag. They consist of saturated fatty acids, branched fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. The variation of fatty acids was revealed in the relative proportions of these fatty acids in different media. The aerobic prokaryotes were the predominant group in all media. The PLFA composition showed significant differences among the eight different media by Tukey＇s honestly test. It was found that steel slag was significantly different in the microbial community as compared to other filter media, probably due to its alkaline effluent. Steel slag alone is probably not a good choice of substratum in constructed wetlands. The principle components analysis （PCA） showed that zeolites, bio-ceramic, shale and vermiculite had a similar microbial community structure while steel slag and ceramic filter media were distinct from other media.展开更多
A novel kind of filter media has been studied using in biological aerated filter process which is produced by waste coal fly ash and coal gangues.The specific surface area and sum of braking and ware rate are viewed a...A novel kind of filter media has been studied using in biological aerated filter process which is produced by waste coal fly ash and coal gangues.The specific surface area and sum of braking and ware rate are viewed as the main factor for determining preparation conditions,including calcination temperature (in the range of 900 ℃ to 1250 ℃),proportion of coal gangue (in the range of 0 to 25%) and soaking time (in the range of 0 to 40 min).The effects of sintering conditions on the main property parameters are researched and the reasons have been analyzed.Considered with all factors,the optimum technological conditions are chosen as follows:the calcination temperature is 1050 ℃ ;the soaking time is 10 min and the proportion of coal gangue is 5%.When at these condition,the main property parameters of the filter media in the technological conditions are 1.6 m 2 /g for the specific surface area and 2.96 % for sum of braking and are rate respectively.Finally,a scanning electron microscope is used for analyzing the microstructure of the filter media.展开更多
Passive cooling techniques are cost effective and reliable methods of cooling remote radio heads (RRH). This paper investigates the plausibility of a passive cooling technique involving exchanging warm air, from the i...Passive cooling techniques are cost effective and reliable methods of cooling remote radio heads (RRH). This paper investigates the plausibility of a passive cooling technique involving exchanging warm air, from the internal cavity of RRHs, with fresh ambient air, to reduce the operating temperature using natural convection across air filters. The results indicate that, an internal air filter tube structure, with width of the enclosure, running vertically up the middle of an RRH, along with 4 pleat filter sides (2.0 ± 0.5 cm separation) provides the most effective outdoor suitable setup out of those examined. This provides a reduction in temperature of 3.9°K ± 0.4°K in the PA and 4.0°K ± 0.4°K in the radio, and a reduction in mass of 0.45 ± 0.05 kg, and is capable of withstanding water ingress and corrosive conditions including wind driven rain and salt fog.展开更多
Biologically active carbon （BAC） system was set up in a water plant of South China during January to December 2007,to study the invertebrate community characteristics of BAC filter.Thirty-seven invertebrate species ...Biologically active carbon （BAC） system was set up in a water plant of South China during January to December 2007,to study the invertebrate community characteristics of BAC filter.Thirty-seven invertebrate species were found,of which 28 belonging to rotifers.Filter operation could lead to an output of invertebrates in high abundances with the filtrate,and the maximum density could reach 5608 individuals/m 3.Average abundances in the effluent water increased in 27-33 folds in comparison to the influent water during the sampling period.Invertebrate community succession had the following trend：filter-feeding animals → small benthic invertebrates → large benthic and resistant invertebrates.Abundances of large-sized invertebrates （copepod adult and oligochaete） at bigger-media column were significantly higher than that at small-media column.The results implied the abundant species diversity of invertebrate in BAC filter.The relationship between invertebrate and biofilm still remain to be studied in detail.展开更多
Filtration of aerosol particles using non-woven fibrous media is a common practice for air cleaning. It has found wide applications in industries and our daily lives. This paper overviews some of these applications an...Filtration of aerosol particles using non-woven fibrous media is a common practice for air cleaning. It has found wide applications in industries and our daily lives. This paper overviews some of these applications and provides an industrial perspective. It starts from discussing aerosol filtration theory, followed by a brief review on the advancement of filtration media. After that, filtration applications in respiratory protection, dust collection, and engine in-take air cleaning are elaborated. These are the areas that the author sees as the typical needed ones in China's fast pace economical development endeavor, where air filtration enables the protection of human health, environment and equipment for sustainability.展开更多
Nutrient pollution still remains one of the greatest challenges to water quality contributing to harmful contaminations water sources,and costly impacts on the economy.This review considers the development of the biof...Nutrient pollution still remains one of the greatest challenges to water quality contributing to harmful contaminations water sources,and costly impacts on the economy.This review considers the development of the biofilters,focusing on the design features that have the most influence on their technical and economic performance.Modern biofilters,based on SAF technology,are particularly suitable for sewage treatment works with throughput rates up to 1,000m^3/d.The main advantages of SAF plants include high quality effluent,low power usage and small footprint.A wide range of filter media are available for different designs,which could be configured for both aerobic and anaerobic treatment in BOD and/or ammonia reduction applications.The two most important parameters for filter media are their Specific Surface Area(SSA,m^2/m^3)and Void Fraction(percentage of void volume or porosity).However,due to the risk of clogging by suspended solids or excess sludge the media used for this application should be limited to about 500m^2/m^3.In tertiary treatment or river restoration applications where the influents tend lack any readily biodegradable substrates,SAF design provides the most appropriate choice for further development to produce effluents with very low nutrient levels.展开更多
The filter paper and activated carbon which filled inside the gas filter have porous media characteristics. In order to study the flow field structure in the filter layer and the activated carbon layer, Computational ...The filter paper and activated carbon which filled inside the gas filter have porous media characteristics. In order to study the flow field structure in the filter layer and the activated carbon layer, Computational Fluid Dynamics method is used to simulate the aerodynamic characteristics of a simplified gas filter. The inertial and viscosity parameters of porous media are solved by Forchheimer equation. The three-dimensional N-S equation and the modified low Reynolds number k-ε turbulence model are adopted to analyze the influence of the explosion-proof plate on the gas filter’s aerodynamic characteristics. The results showed that the air age in the upstream of the activated carbon plates was small, which easily caused the rapid penetration of the Poisonous gas. And in the downstream and around of the activated carbon plates, the air age is larger, formed dead zone, the utilization rate of activated carbon is lower. The explosion-proof plate increases the pressure drop of the gas filter, the air age distribution in the filter layer is more uniform and the utilization rate of filter paper is improved. However, the explosion-proof plate has little influence on the flow field structure of the activated carbon layer.展开更多
In this paper, a new type of resonant Brewster filters （RBF） with surface relief structure for the multiple channels is first presented by using the rigorous coupled-wave analysis and the S-matrix method. By tuning ...In this paper, a new type of resonant Brewster filters （RBF） with surface relief structure for the multiple channels is first presented by using the rigorous coupled-wave analysis and the S-matrix method. By tuning the depth of homogeneous layer which is under the surface relief structure, the multiple channels phenomenon is obtained. Long range, extremely low sidebands and multiple channels are found when the RBF with surface relief structure is illuminated with Transverse Magnetic incident polarization light near the Brewster angle calculated with the effective media theory of sub wavelength grating. Moreover, the wavelengths of RBF with surface relief structure can be easily shifted by changing the depth of homogeneous layer while its optical properties such as low sideband reflection and narrow band are not spoiled when the depth is changed. Furthermore, the variation of the grating thickness does not effectively change the resonant wavelength of RBF, but have a remarkable effect on its line width, which is very useful for designing such filters with different line widths at desired wavelength.展开更多
[目的/意义]为了帮助用户在浩如烟海的社交媒体文本中快速获取所需信息,本研究创新地设计了一种基于过滤注意力机制的自动摘要生成模型Filter Unit Model(FUM)。[方法/过程]首先,采用微调BERT对于输入的社交媒体文本进行向量嵌入;其次,...[目的/意义]为了帮助用户在浩如烟海的社交媒体文本中快速获取所需信息,本研究创新地设计了一种基于过滤注意力机制的自动摘要生成模型Filter Unit Model(FUM)。[方法/过程]首先,采用微调BERT对于输入的社交媒体文本进行向量嵌入;其次,设计了过滤注意力机制来滤除嵌入社交媒体文本中的无用信息,基于字词层面和语句层面两种过滤注意力机制,旨在从不同角度对于嵌入向量进行过滤;最后,采用Transformer的解码器部分进行解码工作,并根据过滤注意力机制的不同设计相应的解码策略。[结果/结论]本研究在微博数据集上与摘要生成领域中经典、优秀的基线模型进行对比实验。实验结果表明,本研究所设计的FUM模型有着比其他基线方法更出色的表现。同时,基于语句层面的过滤注意力机制比基于字词层面的有更好的过滤效果。展开更多
基金supported by the National Natural Science Foundation of China (No.30870221,20877093,50808172)the High Technology Research and Development Program (863) of China (No.2009X207209-004)
文摘Comparisons of microbial community structure, in eight filter media of zeolites, anthracite, shale, vermiculite, ceramic filter media, gravel, steel slag and bio-ceramic, were undertaken by analyzing the phospholipid fatty acid （PLFA） composition. A total of 20 fatty acids in the range of C18to C20 were determined but only 13 PLFAs were detected in steel slag. They consist of saturated fatty acids, branched fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. The variation of fatty acids was revealed in the relative proportions of these fatty acids in different media. The aerobic prokaryotes were the predominant group in all media. The PLFA composition showed significant differences among the eight different media by Tukey＇s honestly test. It was found that steel slag was significantly different in the microbial community as compared to other filter media, probably due to its alkaline effluent. Steel slag alone is probably not a good choice of substratum in constructed wetlands. The principle components analysis （PCA） showed that zeolites, bio-ceramic, shale and vermiculite had a similar microbial community structure while steel slag and ceramic filter media were distinct from other media.
基金Sponsored by the National High Technology Research Development Plan(863)of China(Grant No.2007AA06411)State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(Grant No.2010DX05)the Critical Patented Projects in the Control and Management of the National Polluted Water Bodies(Grant No.2008ZX07207)
文摘A novel kind of filter media has been studied using in biological aerated filter process which is produced by waste coal fly ash and coal gangues.The specific surface area and sum of braking and ware rate are viewed as the main factor for determining preparation conditions,including calcination temperature (in the range of 900 ℃ to 1250 ℃),proportion of coal gangue (in the range of 0 to 25%) and soaking time (in the range of 0 to 40 min).The effects of sintering conditions on the main property parameters are researched and the reasons have been analyzed.Considered with all factors,the optimum technological conditions are chosen as follows:the calcination temperature is 1050 ℃ ;the soaking time is 10 min and the proportion of coal gangue is 5%.When at these condition,the main property parameters of the filter media in the technological conditions are 1.6 m 2 /g for the specific surface area and 2.96 % for sum of braking and are rate respectively.Finally,a scanning electron microscope is used for analyzing the microstructure of the filter media.
文摘Passive cooling techniques are cost effective and reliable methods of cooling remote radio heads (RRH). This paper investigates the plausibility of a passive cooling technique involving exchanging warm air, from the internal cavity of RRHs, with fresh ambient air, to reduce the operating temperature using natural convection across air filters. The results indicate that, an internal air filter tube structure, with width of the enclosure, running vertically up the middle of an RRH, along with 4 pleat filter sides (2.0 ± 0.5 cm separation) provides the most effective outdoor suitable setup out of those examined. This provides a reduction in temperature of 3.9°K ± 0.4°K in the PA and 4.0°K ± 0.4°K in the radio, and a reduction in mass of 0.45 ± 0.05 kg, and is capable of withstanding water ingress and corrosive conditions including wind driven rain and salt fog.
基金supported by the National Hi-Tech Research and Development Program (863) of China(No. 2002AA601120)the National Key TechnologyR &D Program:Shanghai China Expo-Tech Project (No.2007BAK27B05)
文摘Biologically active carbon （BAC） system was set up in a water plant of South China during January to December 2007,to study the invertebrate community characteristics of BAC filter.Thirty-seven invertebrate species were found,of which 28 belonging to rotifers.Filter operation could lead to an output of invertebrates in high abundances with the filtrate,and the maximum density could reach 5608 individuals/m 3.Average abundances in the effluent water increased in 27-33 folds in comparison to the influent water during the sampling period.Invertebrate community succession had the following trend：filter-feeding animals → small benthic invertebrates → large benthic and resistant invertebrates.Abundances of large-sized invertebrates （copepod adult and oligochaete） at bigger-media column were significantly higher than that at small-media column.The results implied the abundant species diversity of invertebrate in BAC filter.The relationship between invertebrate and biofilm still remain to be studied in detail.
文摘Filtration of aerosol particles using non-woven fibrous media is a common practice for air cleaning. It has found wide applications in industries and our daily lives. This paper overviews some of these applications and provides an industrial perspective. It starts from discussing aerosol filtration theory, followed by a brief review on the advancement of filtration media. After that, filtration applications in respiratory protection, dust collection, and engine in-take air cleaning are elaborated. These are the areas that the author sees as the typical needed ones in China's fast pace economical development endeavor, where air filtration enables the protection of human health, environment and equipment for sustainability.
文摘Nutrient pollution still remains one of the greatest challenges to water quality contributing to harmful contaminations water sources,and costly impacts on the economy.This review considers the development of the biofilters,focusing on the design features that have the most influence on their technical and economic performance.Modern biofilters,based on SAF technology,are particularly suitable for sewage treatment works with throughput rates up to 1,000m^3/d.The main advantages of SAF plants include high quality effluent,low power usage and small footprint.A wide range of filter media are available for different designs,which could be configured for both aerobic and anaerobic treatment in BOD and/or ammonia reduction applications.The two most important parameters for filter media are their Specific Surface Area(SSA,m^2/m^3)and Void Fraction(percentage of void volume or porosity).However,due to the risk of clogging by suspended solids or excess sludge the media used for this application should be limited to about 500m^2/m^3.In tertiary treatment or river restoration applications where the influents tend lack any readily biodegradable substrates,SAF design provides the most appropriate choice for further development to produce effluents with very low nutrient levels.
文摘The filter paper and activated carbon which filled inside the gas filter have porous media characteristics. In order to study the flow field structure in the filter layer and the activated carbon layer, Computational Fluid Dynamics method is used to simulate the aerodynamic characteristics of a simplified gas filter. The inertial and viscosity parameters of porous media are solved by Forchheimer equation. The three-dimensional N-S equation and the modified low Reynolds number k-ε turbulence model are adopted to analyze the influence of the explosion-proof plate on the gas filter’s aerodynamic characteristics. The results showed that the air age in the upstream of the activated carbon plates was small, which easily caused the rapid penetration of the Poisonous gas. And in the downstream and around of the activated carbon plates, the air age is larger, formed dead zone, the utilization rate of activated carbon is lower. The explosion-proof plate increases the pressure drop of the gas filter, the air age distribution in the filter layer is more uniform and the utilization rate of filter paper is improved. However, the explosion-proof plate has little influence on the flow field structure of the activated carbon layer.
基金Project supported by the National Natural Science Foundation of China (Grant No 10704079)
文摘In this paper, a new type of resonant Brewster filters （RBF） with surface relief structure for the multiple channels is first presented by using the rigorous coupled-wave analysis and the S-matrix method. By tuning the depth of homogeneous layer which is under the surface relief structure, the multiple channels phenomenon is obtained. Long range, extremely low sidebands and multiple channels are found when the RBF with surface relief structure is illuminated with Transverse Magnetic incident polarization light near the Brewster angle calculated with the effective media theory of sub wavelength grating. Moreover, the wavelengths of RBF with surface relief structure can be easily shifted by changing the depth of homogeneous layer while its optical properties such as low sideband reflection and narrow band are not spoiled when the depth is changed. Furthermore, the variation of the grating thickness does not effectively change the resonant wavelength of RBF, but have a remarkable effect on its line width, which is very useful for designing such filters with different line widths at desired wavelength.
文摘[目的/意义]为了帮助用户在浩如烟海的社交媒体文本中快速获取所需信息,本研究创新地设计了一种基于过滤注意力机制的自动摘要生成模型Filter Unit Model(FUM)。[方法/过程]首先,采用微调BERT对于输入的社交媒体文本进行向量嵌入;其次,设计了过滤注意力机制来滤除嵌入社交媒体文本中的无用信息,基于字词层面和语句层面两种过滤注意力机制,旨在从不同角度对于嵌入向量进行过滤;最后,采用Transformer的解码器部分进行解码工作,并根据过滤注意力机制的不同设计相应的解码策略。[结果/结论]本研究在微博数据集上与摘要生成领域中经典、优秀的基线模型进行对比实验。实验结果表明,本研究所设计的FUM模型有着比其他基线方法更出色的表现。同时,基于语句层面的过滤注意力机制比基于字词层面的有更好的过滤效果。
