检索结果-南通市图书馆

Isolation and application of predatory Bdellovibrio-and-like organisms for municipal waste sludge biolysis and dewaterability enhancement

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2017年第1期11卷 99-109页

作者： Ran yu Shiwen Zhang Zhoukai Chen Chuanyang li Key Laboratory of Energy Thermal Conversion and Control (Ministry of Education) Department of Environmental Science and Engineering School of Energy and Environment Southeast University N anjing 210096 China

Bdellovibrio-and-like organisms （BALOs） are a group of ubiquitous and obligate predatory bacteria and conmlonly used as biocontrol agents. In this study, an efficient, environmental-friendly, and convenient BALOs encouraged municipal waste sludge biolysis pretreatment technique was developed and investigated for dewaterability enhancement of excess waste sludge. The indigenous predatory BALOs were successfully isolated from the sludge for biolysis treatment. Without any chemical addition or pH adjustment, the sludge specific resistance （SRF） and capillary suction time （CST） were significantly reduced by as high as 53.4% and 23.8%, respectively within 24 h＇s treatment, which would further be lowered with the increase of BALOs input dosage. However, the continuous extension of reaction time would women the sludge dewaterability. The decreases of SRF and CST accompanied with the increases of sludge disintegration degree and soluble chemical oxygen demand, nitrogen, and phosphorus concentrations all emphasized the contributions of BALOs＇ predation activities to sludge disturbance, cell lysis, and consequently the release of sludge intracellular water to finally effectively improve the sludge dewaterability and disposal efficiency.

关键词： Bdellovibrio-and-like organisms (BALOs) Biolysis Activated sludge Dewaterability Predation

Microstructures and electrochemical behaviors of casting magnesium alloys with enhanced compression strengths and decomposition rates

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 Magnesium and Alloys 2023年第4期11卷 1213-1223页

作者： Xuewu li Qingyuan yu Xi Chen Qiaoxin Zhang State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China School of Mechanical Engineering Xi’an University of Science and Technology58 Yanta RoadXi’an 710054China School of Mechanical and Electronic Engineering Wuhan University of Technology122 Luoshi RoadWuhan 430070China

New-type magnesium alloy with prominent solubility and mechanical property lays foundation for preparing fracturing part in petroleum ***,Mg-xZn-Zr-SiC alloy is prepared with casting *** and compression tests are conducted to assess the feasibility as decomposable ***,composition,phase and distribution are characterized to investigate decomposition *** indicate that floccule,substrate component and reticulate secondary phase are formed on as-prepared *** also acts out enhanced compression strength to maintain pressure and guarantee stability in dissolution ***,as decomposition time and zinc content increase,couple corrosion intensifies,resulting in gradually enhanced decomposition *** sample decomposition is mainly due to basal anode dissolution,micro particle exfoliation and poor decomposition resistance of corroding *** work shows profound significance in preparing new-type accessible alloy to ensure rapid dissolution of fracturing part and guarantee stable compression strength in oil-gas reservoir exploitation.

关键词： Magnesium alloy Corrosion dissolution Compression strength Electrochemical test Decomposition mechanism

Maternal mental health and well-being during the COVID-19 pandemic in Beijing, China

在线全文

学校读者我要写书评

暂无评论

World Journal of Pediatrics 2021年第3期17卷 280-289页

作者： Zhuang Wei ming-yue Gao Mary Fewtrell Jonathan Wells Jin-yue yu Department of Child Healthcare Beijing Children’s HospitalCapital Medical UniversityNational Center for Children’s HealthBeijingChina Population Policy and Practice Research and Teaching DepartmentUCL Great Ormond Street Institute of Child Health30 Guilford StreetLondon WC1N 1EHUK

Background The aim of this study is to evaluate the impact of the coronavirus disease 2019(COVID-19)pandemic on breastfeeding women and to identify predictors of maternal mental health and *** Mothers aged≥18 years with a breast-fed infant≤18 months of age during the COVID-19 pandemic in Beijing,China,completed a *** analysis of lockdown consequences was performed and predictors of these outcomes were examined using stepwise linear *** Of 2233 participants,29.9%,20.0%and 34.7%felt down,lonely,and worried,respectively,during the lockdown;however,85.3%felt able to *** maternal mental health was predicted by maternal(younger age,higher education)and infant(older age,lower gestation)characteristics,and social circumstances(husband unemployed or working from home,receiving advice from family,having enough space for the baby,living close to a park or green space).Conversely,better maternal mental health was predicted by higher income,employment requiring higher qualifications,more personal space at home,shopping or walking>once/week and lack of impact of COVID-19 on job or *** with higher education,more bedrooms,fair division of household chores and attending an online mother and baby group>once/week reported better *** The findings highlight maternal characteristics and circumstances that predict poorer mental health and reduced coping which could be used to target interventions in any future public health emergencies requiring social restrictions.

关键词： Coping Coronavirus disease 2019 Maternal health Mental health Postpartum

Adaptive dynamic reconfiguration mechanism of unmanned swarm topology based on an evolutionary game

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 Systems Engineering and Electronics 2023年第3期34卷 598-614页

作者： yu minggang NIU Yanjie liU Xueda ZHANG Dongge ZHENG Peng HE ming LUO ling Institute of Command and Control Engineering Army Engineering University of the PLANanjing 210007China Institute of Communication Engineering Army Engineering University of the PLANanjing 210007China

Autonomous cooperation of unmanned swarms is the research focus on“new combat forces”and“disruptive technologies”in military *** mechanism design is the fundamental way to realize autonomous *** the realistic requirements of a swarm network dynamic adjustment under the background of high dynamics and strong confrontation and aiming at the optimization of the coordination level,an adaptive dynamic reconfiguration mechanism of unmanned swarm topology based on an evolutionary game is *** paper analyzes military requirements and proposes the basic framework of autonomous cooperation of unmanned swarms,including the emergence of swarm intelligence,information network construction and collaborative mechanism ***,based on the framework,the adaptive dynamic reconfiguration mechanism is discussed in detail from two aspects:topology dynamics and strategy ***,the unmanned swarms’community network is designed,and the network characteristics are ***,the mechanism characteristics are analyzed by numerical simulation,focusing on the impact of key parameters,such as cost,benefit coefficient and adjustment rate on the level of swarm ***,the conclusion is made,which is expected to provide a theoretical reference and decision support for cooperative mode design and combat effectiveness generation of unmanned swarm operations.

关键词： unmanned swarm operation autonomous collaboration topology reconstruction evolutionary game

Conceptual design and RCS performance research of shipborne early warning aircraft

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2014年第6期25卷 968-976页

作者： Kuizhi yue Yong Gao Guanxiong li Dazhao yu School of Aeronautic Science and Engineering Beihang University Department of Airborne Vehicle Engineering Naval Aeronautical and Astronautical University

In order to improve the survivability of the aircraft,conceptual design and radar cross section（RCS） performance research are done. The CATIA software is used to design the 3D digital model of the shipborne early warning aircraft, and some measures are taken to reduce the RCS characteristics of the early warning aircraft at the same time. Based on the physical optics method and the equivalent electromagnetic flow method,the aircraft＇s RCS characteristics and strength distribution characteristics are simulated numerically, and compared with the foreign advanced shipborne early warning aircraft. The simulation results show that under the X radar band, when the incident wave pitching angle is 0？, compared with the foreign advanced shipborne early warning aircraft, the forward RCS average value of the conceptual shipborne early warning aircraft is reduced to 24.49%, the lateral RCS average value is reduced to 5.04%, and the backward RCS average value is reduced to 39.26%. The research results of this paper are expected to provide theoretical basis and technical support for the conceptual design and the stealth design of the shipborne early warning aircraft.

关键词： conceptual design stealth shipborne early warning aircraft physical optics method simulation

Generalized flyby trajectories around elongated minor celestial bodies as a rotating mass dipole

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2016年第3期32卷 535-545页

作者： Xiangyuan Zeng Baodong Fang Junfeng li Yang yu School of Aerospace Engineering Tsinghua UniversityBeijing 100084 China Shanghai Satellite Engineering Research Institute Shanghai 200240 China Observatoire de la Cote d'Azur 06300 Nice France

The aim of this paper is to understand the common characteristics of the generalized flyby trajectory around natural elongated bodies. Such flyby trajectories provide a short-term mechanism to clear away vicinal objects or temporally capture ejecta into circling orbits. The gravitational potential of elongated bodies is described by a unified approximate model, i.e., the rotating mass dipole which is two point masses connected with a constant massless rod The energy power is used to illustrate the flyby effect in terms of the instantaneous orbital energy. The essential of the single flyby trajectory is studied analytically, and the relationship between the flyby trajectory and its Jacobi integral is also illustrated. Sample trajectories are given to show the variational trend of the energy increment with respect to differen orbital periapsides. The distribution of natural ejecting orbits is presented by varying the parameters of the approximate model.

关键词： Generalized flyby trajectory Natural elongated body Rotating mass dipole Natural ejecting orbits

Main controlling factor and mechanism of gas-in-place content of the Lower Cambrian shale from different sedimentary facies in the western Hubei area, South China

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第3期21卷 1488-1507页

作者： Gang li Xian-ming Xiao Bo-Wei Cheng Chen-Gang Lu yue Feng Dong-Sheng li School of Energy Resources China University of Geosciences(Beijing)Beijing100083China Frontiers Science Center for Deep-time Digital Earth China University of Geosciences(Beijing)Beijing100083 China

The Lower Cambrian shale gas in the western Hubei area,South China has a great resource prospect,but the gas-in-place(GIP)content in different sedimentary facies varies widely,and the relevant mechanism has been not well *** the present study,two sets of the Lower Cambrian shale samples from the Wells YD4 and YD5 in the western Hubei area,representing the deep-water shelf facies and shallowwater platform facies,respectively,were investigated on the differences of pore types,pore structure and methane adsorption capacity between them,and the main controlling factor and mechanism of their methane adsorption capacities and GIP contents were *** results show that the organic matter(OM)pores in the YD4 shale samples are dominant,while the inorganic mineral(IM)pores in the YD5 shale samples are primary,with underdeveloped OM *** pore specific surface area(SSA)and pore volume(PV)of the YD4 shale samples are mainly from micropores and mesopores,respectively,while those of the YD5 shale samples are mainly from micropores and macropores,*** methane adsorption capacity of the YD4 shale samples is significantly higher than that of the YD5 shale samples,with a maximum absolute adsorption capacity of 3.13 cm^(3)/g and 1.31 cm^(3)/g in average,*** with the shallow-water platform shale,the deep-water shelf shale has a higher TOC content,a better kerogen type and more developed OM pores,which is the main mechanism for its higher adsorption *** GIP content models based on two samples with a similar TOC content selected respectively from the Wells YD4 and YD5 further indicate that the GIP content of the deep-water shelf shale is mainly 34 m^(3)/t within a depth range of 1000—4000 m,with shale gas exploration and development potential,while the shallow-water platform shale has normally a GIP content oflittle shale gas *** the geological and geochemical conditions of shale gas formation a

关键词： Lower Cambrian shale Deep-water shelf facies Shallow-waterplat form facies Pore structure Methane adsorption Gas-in-place content Controlling factor

Improvement of wood properties by composite of diatomite and “phenol-melamine-formaldehyde” co-condensed resin

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2013年第4期24卷 741-746页

作者： ZHANG ming XU Yang WANG Shu-liang SHI Jun-you liU Chang-yu WANG Cheng-yu College of Materials Science and Engineering Northeast Forestry University China Nation Center for Quality Supervision and Test of Wood working Machinery Northeast Forestry University Wood Material Science and Engineering Key Laboratory of Jilin Province Beihua University

We improved the overall performance of fast-growing poplar by utilizing a low-cost, effective and simple method. The fast-growing poplar was modified by a vacuum-pressure impregnation method with three types of modification solutions composed of phe- nol-melamine-formaldehyde （PMF） co-condensed resin, diatomite, and 3-aminopropyl （diethoxy） methylsilane. We measured the weight percent gain （WPG）, bulking, leaching, anti-swelling efficiency （ASE）, wa- ter-repellent effectiveness （WRE）, and oxygen index of the modified specimens. All of the wood physical properties, which are beneficial for human uses, were significantly improved by the treatment. We improved various characteristics of wood and the oxygen index of poplar above 48.6% after the modification using diatomite and PMF co-condensed resin.

关键词： Keywords: wood modification phenol-melamine-formaldehydeco-condensed resin artificial fast-growing poplar diatomite

Stress corrosion cracking behavior of buried oil and gas pipeline steel under the coexistence of magnetic field and sulfate-reducing bacteria

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第2期21卷 1320-1332页

作者： Jian-yu He Fei Xie Dan Wang Guang-Xin liu ming Wu yue Qin College of Petroleum Engineering Liaoning Petrochemical UniversityFushun113001LiaoningChina Key Laboratory of Oil and Gas Storage and Transportation Technology in liaoning Province Fushun113001LiaoningChina State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing100084China PipeChina West East Gas Pipeline Company Shanghai200120China

Magnetic field and microorganisms are important factors influencing the stress corrosion cracking(SCC)of buried oil and gas pipelines. Once SCC occurs in buried pipelines, it will cause serious hazards to the soil environment. The SCC behavior of X80 pipeline steel under the magnetic field and sulfate-reducing bacteria(SRB) environment was investigated by immersion tests, electrochemical tests, and slow strain rate tensile(SSRT) tests. The results showed that the corrosion and SCC sensitivity of X80 steel decreased with increasing the magnetic field strength in the sterile environment. The SCC sensitivity was higher in the biotic environment inoculated with SRB, but it also decreased with increasing magnetic field strength, which was due to the magnetic field reduces microbial activity and promotes the formation of dense film layer. This work provided theoretical guidance on the prevention of SCC in pipeline steel under magnetic field and SRB coexistence.

关键词： Magnetic field Sulfate-reducing bacteria Film layer Stress corrosion cracking Oil and gas pipelines