检索结果-南通市图书馆

Thermodynamic prediction and experimental investigation of short-term dynamic membrane formation in dynamic membrane bioreactors:Effects of sludge properties

引用

Journal of Environmental Sciences 2019年第3期31卷 85-96页

作者： Zhenzhen Yu Yisong Hu Mawuli Dzakpasu Xiaochang C.Wang Key lab of Northwest Water Resource Environment and Ecology MOE Xi'an University of Architecture and Technology International Science & Technology Cooperation Center for Urban Alternative Water Resources Development Key lab of Environmental Engineering Shaanxi Province

In dynamic membrane bioreactors(DMBRs), a dynamic membrane(DM) forms on a support material to act as the separation membrane for solids and liquids. In this study, batch filtration tests were carried out in a DMBR using nylon mesh(25 μm) as support material to filtrate sludge suspensions of variable properties from three different sources to evaluate the effects on the short-term DM formation process(within 240 min). Furthermore, the extended Derjaguin–Landau–Verwey–Overbeek(XDLVO) theory was applied to analyze the sludge adhesion and cohesion behaviors on the mesh surface to predict quantitative parameters of the short-term DM formation process(including initial formation and maturation stage). The filtration results showed that the order of the initial DM formation time(permeate turbidity lability. Moreover, normal sludge(regarding settleability, dewaterability,flocculability, and extracellular polymeric substance) showed a more acceptable DM formation performance(short DM formation time, low permeate turbidity, and high permeate flux) than sludge with poor settleability, dewaterability and flocculability. The influence of sludge properties on the initial DM formation time corroborates the prediction of sludge adhesion behaviors by XDLVO theory. Additionally, the XDLVO calculation results showed that acid–based interaction, energy barrier, and secondary energy minimum were important determinants of the sludge adhesion and cohesion behaviors. Therefore, short-term DM formation process may be enhanced to achieve stable long-term DMBR operation through positive modification of the sludge properties.

关键词： Dynamic membrane bioreactor Dynamic membrane formation XDLVO theory Sludge properties Wastewater treatment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Structural Investigation of Solid Methane at High Pressure

引用

Chinese Physics Letters 2010年第6期27卷 141-143页

作者： ZHAO Juan FENG Wan-Xiang LIU Zhi-Ming MA Yan-Ming HE Zhi CUI Tian ZOU Guang-Tian State Key lab of Superhaxd Materials College of Physics Jilin University Changchun 130012

High pressure studies of solid methane are performed using both classical simulated annealing and first-principles methods. A series of simulated annealing and geometry optimization reveal a monoclinic P21/b structure with the unit cell containing four methane molecules. The phonon dispersion curves and vibrational density of states indicate that this structure is stable in the pressure range 10-90 GPa. The electronic band structure and density of states show that this structure has not metalized until 90 GPa.

关键词： Pressure Methane Simulation Lymphocytes Dispersants Density

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Using multi-threads to hide deduplication I/O latency with low synchronization overhead

引用

Journal of Central South University 2013年第6期20卷 1582-1591页

作者：朱锐秦磊华周敬利郑寰 School of Computer Huazhong University of Science and Technology Wuhan National lab for Optoelectronics

Data deduplication, as a compression method, has been widely used in most backup systems to improve bandwidth and space efficiency. As data exploded to be backed up, two main challenges in data deduplication are the CPU-intensive chunking and hashing works and the I/0 intensive disk-index access latency. However, CPU-intensive works have been vastly parallelized and speeded up by multi-core and many-core processors; the I/0 latency is likely becoming the bottleneck in data deduplication. To alleviate the challenge of I/0 latency in multi-core systems, multi-threaded deduplication （Multi-Dedup） architecture was proposed. The main idea of Multi-Dedup was using parallel deduplication threads to hide the I/0 latency. A prefix based concurrent index was designed to maintain the internal consistency of the deduplication index with low synchronization overhead. On the other hand, a collisionless cache array was also designed to preserve locality and similarity within the parallel threads. In various real-world datasets experiments, Multi-Dedup achieves 3-5 times performance improvements incorporating with locality-based ChunkStash and local-similarity based SiLo methods. In addition, Multi-Dedup has dramatically decreased the synchronization overhead and achieves 1.5-2 times performance improvements comparing to traditional lock-based synchronization methods.

关键词： multi-thread multi-core parallel data deduplication

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

New statistical model for radar HRRP target recognition

引用

Journal of Systems Engineering and Electronics 2010年第2期21卷 204-210页

作者： Qingyu Hou Feng Chen Hongwei Liu Zheng Bao National lab of Radar Signal Processing Xidian University Xi'an 710071 R R. China

The mixture of factor analyzers （MFA） can accurately describe high resolution range profile （HRRP） statistical charac- teristics. But how to determine the proper number of the models is a problem. This paper develops a variational Bayesian mixture of factor analyzers （VBMFA） model. This procedure can obtain a lower bound on the Bayesian integral using the Jensen＇s inequality. An analytical solution of the Bayesian integral could be obtained by a hypothesis that latent variables in the model are indepen- dent. During computing the parameters of the model, birth-death moves are utilized to determine the optimal number of model au- tomatically. Experimental results for measured data show that the VBMFA method has better recognition performance than FA and MFA method.

关键词： radar automatic target recognition (RATR) high reso- lution range profile (HRRP) variational Bayesian mixtures of factor analyzers (VBMFA) variational Bayesian(VB) mixtures of factor analyzers (MFA).

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Extending attributes page:a scheme for enhancing the reliability of storage system metadata

引用

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第8期10卷 1106-1113页

作者： Juan WANG Dan FENG Fang WANG Cheng-tao LU MOE Key lab of Data Storage System Huazhong University of Science and Technology Wuhan 430074 China

In an object-based storage system,a novel scheme named EAP(extending attributes page) is presented to enhance the metadata reliability of the system by adding the user object file information attributes page for each user object and storing the file-related attributes of each user object in object-based storage *** EAP scheme requires no additional hardware equipments compared to a general method which uses backup metadata servers to improve the metadata *** a Markov chain,this paper compares the metadata reliability of the system using the EAP scheme with that using only metadata servers to offer the file metadata *** results demonstrate that the EAP scheme can dramatically enhance the reliability of storage system metadata.

关键词： Metadata server Metadata reliability Markov model Extending attributes page (EAP)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Water Transport Models of Moisture Absorption and Sweat Discharge Yarns

引用

Journal of Donghua University(English Edition) 2008年第5期25卷 594-596页

作者：王发明周小红王善元 The Key lab of Textile Science & Technology Ministry of Education Donghua University The Key lab of Advanced Textile Materials & Manufacturing Technology Ministry of Education China Zhejiang Sci-Tech University

An important property of moisture absorption and sweat discharge yarns is their water transport property. In the paper, two water transport models of moisture absorption and sweat discharge yarns were developed to investigate the influence factors on their wicking rate. In parallel Column Pores Model, wicking rate is determined by the equivalent capillary radius R and length of the capillary tube L. In Pellets Accumulation Model, wicking rate is decided by the capillary radius r and length of the fiber unit assemble L0.

关键词： water transport capillary action parallel column pores model pellets accumulation model moisture absorption & sweat discharge yarn

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Dynamic membrane bioreactor performance enhancement by powdered activated carbon addition:Evaluation of sludge morphological,aggregative and microbial properties

引用

Journal of Environmental Sciences 2019年第1期31卷 73-83页

作者： Zhenzhen Yu Yisong Hu Mawuli Dzakpasu Xiaochang C.Wang Huu Hao Ngo Key lab of Northwest Water Resource Environment and Ecology MOE Xi'an University of Architecture and Technology International Science & Technology Cooperation Center for Urban Alternative Water Resources Development Key lab of Environmental Engineering Centre for Technology in Water and Wastewater School of Civil and Environmental Engineering University of Technology Sydney

The effects of powdered activated carbon(PAC) addition on sludge morphological, aggregative and microbial properties in a dynamic membrane bioreactor(DMBR) were investigated to explore the enhancement mechanism of pollutants removal and filtration performance. Sludge properties were analyzed through various analytical measurements. The results showed that the improved sludge aggregation ability and the evolution of microbial communities affected sludge morphology in PAC-DMBR, as evidenced by the formation of large, regularly shaped and strengthened sludge flocs. The modifications of sludge characteristics promoted the formation process and filtration flux of the dynamic membrane(DM) layer. Additionally, PAC addition did not exert very significant influence on the propagation of eukaryotes(protists and metazoans)and microbial metabolic activity. High-throughput pyrosequencing results indicated that adding PAC improved the bacterial diversity in activated sludge, as PAC addition brought about additional microenvironment in the form of biological PAC(BPAC), which promoted the enrichment of Acinetobacter(13.9%), Comamonas(2.9%), Flavobacterium(0.31%) and Pseudomonas(0.62%), all contributing to sludge flocs formation and several(such as Acinetobacter) capable of biodegrading relatively complex organics. Therefore, PAC addition could favorably modify sludge properties from various aspects and thus enhance the DMBR performance.

关键词： Dynamic membrane bioreactor Powdered activated carbon Sludge property Filtration performance Wastewater treatment Microbial community

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modeling of highly efficient drug delivery system induced by self-assembly of nanocarriers: A density functional study

引用

Science China Chemistry 2013年第2期56卷 249-255页

作者： JIANG Jian CAO DaPeng Division of Molecular and Materials Simulation State Key Lab of Organic-Inorganic Composites Beijing University of Chemical Technology

Owing to the importance of drug delivery in cancer or other diseases' therapy, the targeted drug delivery (TDD) system has been attracting enormous interest. Herein, we model the TDD system and design a novel rod-like nanocarrier by using the coarse grained model-based density functional theory, which combines a modified fundamental measure theory for the excluded-volume effects, Wertheim's first-order thermodynamics perturbation theory for the chain connectivity and the mean field approximation for van der Waals attraction. For comparison, the monomer nanocarrier TDD system and the no nanocarrier one are also investigated. The results indicate that the drug delivery capacity of rod-like nanocarriers is about 62 times that of the no nanocarrier one, and about 6 times that of the monomer nanocarriers. The reason is that the rod-like nanocarriers would self-assemble into the smectic phase perpendicular to the membrane surface. It is the self-assembly of the rod-like nanocarriers that yields the driving force for the targeted delivery of drugs inside the cell membrane. By contrast, the conventional monomer nanocarrier drug delivery system lacks the driving force to deliver the drugs into the cell membrane. In short, the novel rod-like nanocarrier TDD system may improve the drug delivery efficiency. Although the model in this work is simple, it is expected that the system may provide a new perspective for cancer targeted therapy.

关键词： interface polymers microstructure statistical thermodynamics self-assembly targeted drug delivery

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Analysis of intron sequence variability of the conservative HMG-box of Sox9 genes in allotetraploids and their original parents

引用

Progress in Natural Science:Materials International 2007年第5期17卷 537-543页

作者： Liu Jifang, Liu Shaojun , Tao Min, Li Wei and Liu Yun (Key laboratory of Protein Chemistry and Developmental Biology of State Education Ministry of China, College of Life Sciences, Hunan Normal University, Changsha 410081, China) Key lab. of Protein Chemistry and Developmental Biology MOE College of Life Sciences Hunan Normal University Changsha 410081 China

The Sox genes of allotetraploids and their original maternal red crucian carp (Carassius caassius red var.) and original paternal common carp (Cyprinus carpio L.) were detected by PCR with the designed primers based on the conserved HMG-box sequence in different species. Sequencing of Sox genes indicated that two Sox9 genes (Atsox9a and Atsox9b) existed in allotetraploids, while only one Sox9 gene existed in red crucian carp (Rcsox9a) and common carp (Ccsox9b) . All of the four Sox9 genes contained an intron in the HMG-box. with the sizes of 413 bp, 703 bp, 401 bp and 714 bp, respectively. Moreover, the introns obeyed the rule of "GT-AG" . A high similarity was observed between introns of Atsox9a and Rcsox9a (94.4%), Atsox9b and Ccsox9b (97.8%). Interestingly, the deduced amino acid sequences of their corresponding exons all shared 100% identity. Thus, introns of the HMG-domain of Sox9s in allotetraploids and their original parents have not only the length polymorphism but also intron variability. Our results provide significant molecular evidence for the origin and evolution of allotetraploids.

关键词： Sox9 intron genetic variability phylogenesis.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

A method of determining the permeability coefficient of coal seam based on the permeability of loaded coal

引用

International Journal of Mining Science and Technology 2014年第5期24卷 637-641页

作者： Li Bo Wei Jianping Wang Kai Li Peng Wang Ke State Key lab Cultivation Base Henan Province Key Lab of Gas Geology & Gas Control Henan Polytechnic University School of Materials Science and Engineering Henan Polytechnic University School of Resources & Safety Engineering China University of Mining & Technology

This study developed the equipment for thermo-fluid–solid coupling of methane-containing coal, and investigated the seepage character of loaded coal under different working conditions. Regarding the effective pressure as a variable, the variation characteristics of the gas permeability of loaded methane-containing coal has been studied under the conditions of different confining pressures and pore pressures. The qualitative and quantitative relationship between effective stress and permeability of loaded methane-containing coal has been established, considering the adsorption of deformation, amount of pore gas compression and temperature variation. The results show that the permeability of coal samples decreases along with the increasing effective stress. Based on the Darcy law, the correlation equation between the effective stress and permeability coefficient of coal seam has been established by combining the permeability coefficient of loaded coal and effective stress. On the basis of experimental data, this equation is used for calculation, and the results are in accordance with the measured gas permeability coefficient of coal seam. In conclusion, this method can be accurate and convenient to determine the gas permeability coefficient of coal seam, and provide evidence for forecasting that of the deep coal seam.

关键词： Permeability coefficient Coal seam Effective pressure Loaded coal Pore pressure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：