检索结果-南通市图书馆

Antibacterial potency of housefly larvae extract from sewage sludge through bioconversion

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2013年第9期25卷 1897-1905页

作者： Chaocheng Zheng Lixiang Zhou Department of Environmental Engineering College of Resources and Environmental Science Nanjing Agricultural University

Use of the fly to convert sewage sludge into nutrient-rich soil conditioner and amendment is an attractive approach for sludge bioconversion. During this process, fecal coliforms, an indicating pathogen, in sludge were reduced to 5.3 × 102 most probable number /g dry solid from initial 3.32 × 106 MPN/g dry solid. It was also found that the extract of larvae grown in sludge during bioconversion have an observable inhibitory effect against bacteria compared to larvae grown in wheat bran as measured by minimum bacterial concentration tests. In vitro antimicrobial assay tests over time also showed that the extract had strong inhibitory efficiencies of ca. 99% against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Serratia marcescens, while the efficiency was 69% and 57% against Bacillus subtilis and Klebsiella pneumoniae, respectively. The observed pathogenic bacterial cell membrane damage was found to be responsible for the phenomenon mentioned above, with nuclear acids leaching out quickly and alkaline phosphatase increasing in the outer membrane, followed by an increase of β-galactosidase in the inner membrane. Clearly, housefly larvae extract from sewage sludge through bioconversion possesses antibacterial potency against pathogenic bacteria.

关键词： sewage sludge larvae extract anti-bacterial membrane permeability

Finite Groups with Some Pronormal Subgroups

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2011年第4期27卷 715-724页

作者： Zhen Cai SHEN Wu Jie SHI School of Mathematical Sciences Suzhou University Suzhou 215006 P. R. China School of Mathematics and Statistics Chongqing University of Arts and Sciences Chongqing 402160 P. R. China

A subgroup H of finite group G is called pronormal in G if for every element x of G, H is conjugate to Hx in （H, Hx）. A finite group G is called PRN-group if every cyclic subgroup of G of prime order or order 4 is pronormal in G. In this paper, we find all PRN-groups and classify minimal non-PRN-groups （non-PRN-group all of whose proper subgroups are PRN-groups）. At the end of the paper, we also classify the finite group G, all of whose second maximal subgroups are PRN-groups.

关键词： Pronormal subgroups PRN-groups minimal non-PRN-groups PN-groups minimalsubgroups p-nilpotent groups

Structural characterization and optical properties of long-lasting CaAl2O4：Eu2＋,Nd3＋ phosphors synthesized by microwave-assisted chemical co-precipitation

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

Journal of Rare Earths 2017年第7期35卷 652-657页

作者：余媛王建王纪冬李婧朱亚楠李晓强宋晓蕾葛明桥 Key Laboratory of Eco- Textile of Ministry of Education College of Textiles and Clothing Jiangnan University Wuxi 214122 China

The present paper reported the structural and luminescent properties of Eu^（2＋） and Nd^（3＋） doped CaAl_2O_4 phosphor. The samples were prepared by microwave-assisted chemical co-precipitation（MA-CCP）, a synthesis technique which is suitable for small and uniform particle that could be used directly without grinding. The effects of different microwave temperatures on structure and photoluminescence behavior were studied. Formation of a phosphor and phase purity were confirmed by X-ray diffraction technique（XRD） with variable microwave temperatures. XRD analysis showed that the phosphors prepared by MA-CCP method at the temperature of 750, 900oC, respectively and solid-state reaction（SSR） method at 1300oC consisted of impurities. Commission Internationale de L＇Eclairage（CIE） color coordinates of CaAl_2O_4：Eu^（2＋）,Nd^（3＋） were suitable as blue light emitting phosphor. Excitation and emission peaks of the samples prepared by different methods in this study were almost the same. The images of SEM showed that the size of the phosphors prepared by MA-CCP method reached a submicrometer.

关键词： CaAl2O4 Eu2+ Nd3+ microwave co-precipitation optical properties structural rare earths

Evaluation of hollow fiber T-type zeolite membrane modules for ethanol dehydration

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2017年第5期25卷 581-586页

作者： Xuerui Wang Ji Jiang Dezhong Liu Youquan Xue Chun Zhang Xuehong Gu State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemistry and Chemical EngineeringThe Synergetic Innovation Center for Advanced MaterialsNanjing Tech University

This work presents the design of hollow fiber T-type zeolite membrane modules with different geometric configurations. The module performances were evaluated by pervaporation dehydration of ethanol/water mixtures. Strong concentration polarization was found for the modules with big membrane bundles. The concentration polarization was enhanced at high temperature due to the higher water permeation flux. The increase of feed flow could improve water permeation flux for the membrane modules with small membrane *** fluid dynamics was used to visualize the flow field distribution inside of the modules with different configurations. The membrane module with seven bundles exhibited highest separation efficiency due to the uniform distribution of flow rate. The packing density could be 10 times higher than that of the tubular membrane module. The hollow fiber membrane module exhibited good stability for ethanol dehydration.

关键词： Hollow fiber Module Pervaporation T-type zeolite membrane

Strength and deformation characteristics of carbonated reactive magnesia treated silt soil

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2015年第5期22卷 1859-1868页

作者：蔡光华刘松玉杜延军章定文郑旭 Institute of Geotechnical Engineering Southeast University

A series of unconfined compression tests(UCTs) were conducted to investigate the effects of content of reactive magnesia(Mg O) and carbonation time on the engineering properties including apparent characteristics, stress-strain relation, and deformation and strength characteristics of reactive Mg O treated silt soils. The soils treated with reactive Mg O at various contents were subjected to accelerated carbonation for different periods of time and later, UCTs were performed on them. The results demonstrate that the reactive Mg O content and carbonation time have remarkable influences on the aforementioned engineering properties of the soils. It is found that with the increase in reactive Mg O content, the unconfined compressive strength(qu) increases at a given carbonation time(<10 h), whereas the water content and amounts of crack of the soils decrease. A threshold content of reactive Mg O exists at approximately 25% and a critical carbonation time exists at about 10 h for the development of qu. A simple yet practical strength-prediction model, by taking into account two variables of reactive Mg O content and carbonation time, is proposed to estimate qu of carbonated reactive Mg O treated soils. A comparison of the predicated values of qu with the measured ones indicates that the proposed model has satisfactory accuracy.

关键词： carbon dioxide accelerated carbonation reactive magnesia unconfined compressive strength strength-prediction model

A random walk evolution model of wireless sensor networks and virus spreading

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2013年第1期22卷 154-160页

作者：王亚奇杨晓元 Network and Information Security Key Laboratory of the Armed Police Force Department of Electronics Technology Engineering University of the Chinese People's Armed Police Force

In this paper, considering both cluster heads and sensor nodes, we propose a novel evolving a network model based on a random walk to study the fault tolerance decrease of wireless sensor networks （WSNs） due to node failure, and discuss the spreading dynamic behavior of viruses in the evolution model. A theoretical analysis shows that the WSN generated by such an evolution model not only has a strong fault tolerance, but also can dynamically balance the energy loss of the entire network. It is also found that although the increase of the density of cluster heads in the network reduces the network efficiency, it can effectively inhibit the spread of viruses. In addition, the heterogeneity of the network improves the network efficiency and enhances the virus prevalence. We confirm all the theoretical results with sufficient numerical simulations.

关键词： wireless sensor network random walk network efficiency virus spreading

Insights into friction behavior of textured amorphous carbon and lubricant composite system: Dependence on the lubricant viscosity and textured shape

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2023年第5期33卷 616-624页

作者： Jiaqing Ding Naizhou Du Xubing Wei Xiaowei Li Zan Chen Shiqi Lu Haolin Zhang Cunao Feng Kai Chen Jianghao Qiao Dekun Zhang Kwang-Ryeol Lee School of Materials Science and Physics China University of Mining and Technology Key Laboratory of Marine Materials and Related Technologies Zhejiang Key Laboratory of Marine Materials and Protective Technologies Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Computational Science Center Korea Institute of Science and Technology

Combining textured amorphous carbon(a-C) film with lubricant achieves ultra-low friction to improve the mechanical component’s service life. However, the coupling influence of lubricant viscosity and textured shape on friction behavior and interfacial transformation are still unclear. In this work, the evolution of friction performance with Poly-alpha-olefin viscosities and its dependence on textured shapes were investigated by reactive molecular dynamics simulation. Results reveal that as the textured shape is fixed, increasing the lubricant viscosity causes friction coefficient to decline first and then increase, due to the hydrodynamic lubrication and regional aggregation of lubricant. While under same lubricant condition, rectangular textured systems exhibit lower friction coefficient than circular textured ones, attributing to the formation of stable lubricant film without serious aggregation.

关键词： Amorphous carbon Surface texture Lubricant Reactive molecular dynamics

Bifurcation and chaos in high-frequency peak current mode Buck converter

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2016年第7期25卷 171-178页

作者：常昌远赵欣杨帆吴承恩 School of Integrated Circuit Southeast University

Bifurcation and chaos in high-frequency peak current mode Buck converter working in continuous conduction mode（CCM） are studied in this paper. First of all, the two-dimensional discrete mapping model is established. Next, reference current at the period-doubling point and the border of inductor current are derived. Then, the bifurcation diagrams are drawn with the aid of MATLAB. Meanwhile, circuit simulations are executed with PSIM, and time domain waveforms as well as phase portraits in i_L–v_C plane are plotted with MATLAB on the basis of simulation data. After that, we construct the Jacobian matrix and analyze the stability of the system based on the roots of characteristic equations. Finally, the validity of theoretical analysis has been verified by circuit testing. The simulation and experimental results show that,with the increase of reference current I_（ref）, the corresponding switching frequency f is approaching to low-frequency stage continuously when the period-doubling bifurcation happens, leading to the converter tending to be unstable. With the increase of f, the corresponding Irefdecreases when the period-doubling bifurcation occurs, indicating the stable working range of the system becomes smaller.

关键词： peak current mode Buck converter high frequency bifurcation chaos

A Multifrequency Cloak with a Single Shell of Negative Index Metamaterials

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第6期28卷 134-136页

作者： LI Pei-Ning LIU You-Wen MENG Yun-Ji ZHU Min-Jun College of Science Nanjing University of Aeronautics and AstronauticsNanjing 210016

We propose an invisibility multifrequency cloak with a single shell of negative index metamaterials(NIMs)based on the scattering cancellation cloaking *** and simulation results show that the cloak can reduce the total scattering cross section at multiple frequencies by exploiting the frequency dispersion of the permittivity and permeability *** may provide a potential way to design a multifrequency cloak.

关键词： theory visibility scattering