检索结果-南通市图书馆

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

The effect of time of day on driver's injury severity at highway-rail grade crossings in the United States

在线全文

学校读者我要写书评

暂无评论

Journal of Traffic and Transportation Engineering(English Edition) 2016年第1期3卷 37-50页

作者： Wei Hao Camille Kamga dan wan Department of Civil and Environmental Engineering New Jersey Institute of Technology University Heights Newark University Transportation Research Center City College of New York

Based on the Federal Railway Administration （FILE} database, there were totally 25,945 highway-rail crossing crashes happened in the United States between 2002 and 201I. With an extensive research, analysis results showed that there were substantial differences by time of day for driver＇s injury severity at highway-rail grade crossings. However, there is no published study on time of day analysis of driver＇s injury given that a highway-rail grade crossing crash happens. This study applied ordered probit models to explore the de- terminants of injury severity for motor vehicle drivers at highway-rail grade crossings. The results show that motor vehicle driver＇s injury severity in highway-rail grade crossing crashes that happen during a.m. peak, p.m. peak, and p.m. off-peak is extremely higher than other time periods. However, speed control will significantly reduce driver＇s injury severity. In addition, crashes that happen during early morning, a.m. peak, and p.m. peak are more likely to be influenced by vehicle speed and train speed compared with other time periods. Paved highways will significantly help to reduce driver＇s injury severity at highway-rail grade crossings. Drivers during peak hours, early morning and p.m. off-peak are more likely to be influenced by unpaved roadway compared with other time periods.

关键词： Injury severityTime of dayHighway-rail grade crossingOrdered probit model

Peritidal carbonate cycles induced by carbonate productivity variations:A conceptual model for an isolated Early Triassic greenhouse platform in South China

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2014年第2期3卷 115-126页

作者： wan Yang dan J.Lehrmann Geology and Geophysics Program Missouri University of Science and Technology Department of Geosciences Trinity University

Eustasy has commonly been invoked to explain peritidal carbonate cyclicity,but is difficult to explain cycles formed in a greenhouse climate when eustasy is *** propose that peritidal cycles on an Early Triassic isolated carbonate platform in Guizhou,South China,were formed by hierarchical carbonate productivity *** of the 149 shallowing-upward cycles are typically terminated by flooding over intertidal facies and contain rare supratidal facies and no prolonged subaerial ***-diversity benthos in the platform interior during the post-end-Permian biotic recovery were sensitive to environmental perturbations,which caused variations in benthic sediment productivity in the subtidal carbonate *** perturbations may be driven by changes in salinity and degree of eutrophication,or repeated platform mini-drowning by anoxic and/or CO2-charged deep water upwelled onto the *** were modulated by Milankovitch orbitally-driven climatic and oceanographic factors as suggested by the hierarchical stacking pattern and spectral signals of these cycles.A one-dimensional conceptual model shows that hierarchical productivity variations alone may generate hierarchical peritidal carbonate cycles under conditions of constant subsidence and no sea-level fluctuation.

关键词： carbonate peritidal cycle productivity climate Triassic South China

Pollution characteristics of polycyclic aromatic hydrocarbons in common used mineral oils and their transformation during oil regeneration

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2017年第6期29卷 247-253页

作者： Xiaohui Wu Bo yue Yi Su Qi wan Qifei Huang Qunhui wang Hongying Cai State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental Sciences Beijing 100012China Civil and Environmental Engineering Institute University of Science and Technology BeijingBeijing 100083China The Solid Waste Management Center of Chongqing Chongqing 401147China

The pollution characteristic of polycyclic aromatic hydrocarbons （PAHs） in common used mineral oils, semi-refined oils, refined oils and solid wastes produced during the used mineral oil regeneration process was analyzed. The results showed that total PAHs content in six common used mineral oils was as follows： used engine oil 〉 used quenching oil 〉 used casting oil 〉 used hydraulic oil 〉 used antimst oil 〉 used industrial lubricating oil. Furthermore, this order was dependent on the source of PAHs and oil working temperatures. Additionally, total PAt-Is content in regenerated oils was as follows： semi-refined oil 〉 refined oil 〉 crude oil, which was related to the catalytic cracking process of crude oil and adsorption refining process of semi-refined oil. The ranking of total PAHs content in regenerated wastes varied depending on the regeneration technology used as follows： waste adsorption sand 〉 acid sludge 〉 waste clay 〉 precipitation sludge 〉 cracked residue. In all types of used mineral oils and regenerated wastes, the maximum and minimum proportions of the total PAHs content were composed of 2-3 ring-PAHs and 5-6 ring-PAHs, respectively. The majority of PAHs in the used mineral oils entered into regenerated wastes during regeneration process, while a small number remained in the regenerated oil.

关键词： Used mineral oilPAHsPollution characteristicsRegenerationTransformation

TIME-IGGCAS model validation:Comparisons with empirical models and observations

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2008年第3期51卷 308-322页

作者： yue XinAn wan WeiXing LIU LiBo NING BaiQi ZHAO BiQiang ZHANG ManLian Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029China Wuhan Institute of Physics and Mathematics Chinese Academy of SciencesWuhan 430071China Graduate University Chinese Academy of SciencesBeijing 100049China

The TIME-IGGCAS (Theoretical Ionospheric Model of the Earth in Institute of Ge- ology and Geophysics, Chinese Academy of Sciences) has been developed re- cently on the basis of previous works. To test its validity, we have made compari- sons of model results with other typical empirical ionospheric models (IRI, NeQuick-ITUR, and TItheridge temperature models) and multi-observations (GPS, Ionosondes, Topex, DMSP, FORMOSAT, and CHAMP) in this paper. Several conclu- sions are obtained from our comparisons. The modeled electron density and elec- tron and ion temperatures are quantitatively in good agreement with those of em- pirical models and observations. TIME-IGGCAS can model the electron density variations versus several factors such as local time, latitude, and season very well and can reproduce most anomalistic features of ionosphere including equatorial anomaly, winter anomaly, and semiannual anomaly. These results imply a good base for the development of ionospheric data assimilation model in the future. TIME-IGGCAS underestimates electron temperature and overestimates ion tem- perature in comparison with either empirical models or observations. The model results have relatively large deviations near sunrise time and sunset time and at the low altitudes. These results give us a reference to improve the model and enhance its performance in the future.

关键词： ionosphere theoretical model empirical model satellite observation relative deviation

Production of functional sperm from in vitro-cultured premeiotic spermatogonia in a marine fish

在线全文

学校读者我要写书评

暂无评论

Zoological Research 2022年第4期43卷 537-551页

作者： Hong Zhang wan-wan Zhang Cheng-Yu Mo Meng-dan Dong Kun-Tong Jia Wei Liu Mei-Sheng Yi School of Marine Sciences Sun Yat-Sen UniversityGuangzhouGuangdong 510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) ZhuhaiGuangdong 519000China Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering GuangzhouGuangdong 510000China

In vitro production of functional gametes can revolutionize reproduction by reducing generation intervals and accelerating genetic breeding in aquaculture,especially in fish with relatively long ***,functional sperm production from in vitro-cultured spermatogonia remains a challenge in most aquaculture *** this study,we isolated and characterized premeiotic spermatogonia from marine four-eyed sleepers(Bostrychus sinensis),which are prone to ovotesticular or sterile testicular development,and induced the differentiation of the spermatogonia into flagellated sperm in a three-dimensional(3D)culture *** insemination indicated that the in vitro-derived sperm were capable of fertilizing mature oocytes to develop into normal ***,melatonin significantly promoted spermatogonia proliferation and differentiation through the ERK1/2 signaling pathway,and thus increased the efficiency in functional sperm *** 3D culture system and resulting functional sperm hold great promise for improving the genetic breeding of aquaculture fish.

关键词： In vitro spermatogenesis 3D culture model Spermatogonia Four-eyed sleeper Melatonin Genetic breeding

Variation in morphological traits in a recent hybrid zone between closely related Quercus liaotungensis and ***(Fagaceae)

在线全文

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2015年第2期8卷 224-229页

作者： Lai Wei yue-Fei Li Han Zhang wan-Jin Liao State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering Beijing Normal University19 Xinjiekouwai StreetHaidianBeijing 100875China

Aims Hybridization usually leads to gene introgression between related spe-cies in hybrid zones,associated with complex patterns of morpho-logical ***,previous studies have tended to ignore the effects of geographic variation in hybridization rates on species *** study aims to investigate the variation of morphologi-cal traits between two sympatric and taxonomically confused oak spe-cies,Quercus liaotungensis and ***,and reveal the effects of hybridization rates on morphological traits and the taxonomic *** We used seven microsatellite loci to evaluate species status and measured 15 morphological traits in 26 trees in the recent hybrid zone between *** and ***,and we char-acterized the differences between the two oak species and their hybrids for the investigated *** Findingsmolecular analyses indicated that 74%of 78 sampled maternal trees were hybrids between *** and *** although the observed morphological variation suggested that they had remained distinct *** all of the differentiated leaf and reproductive traits,the hybrids expressed patterns similar to ***,which may suggest dominant expression of paren-tal *** results are consistent with our expectation that hybrids will be difficult to distinguish from parental species in a recent hybrid zone.

关键词： Fagaceae morphological taxonomy recent hybrid zone Quercus

Method of ballistic control and projectile rotation in a novel railgun

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

Defence Technology（防务技术） 2018年第5期14卷 628-634页

作者： Bo Tang Ying-tao Xu Gang wan Jiang yue Yong Jin Hai-yuan Li National Key Laboratory of Transient Physics Nanjing University of Science and Technology

In order to realize the ballistic control of the railgun and the flight stability of the projectile, a new type of railgun is designed, which can control the muzzle velocity and rotation rate. The method of the muzzle velocity and overload control is to adjust the voltage or other parameters of pulse power supply. It would be easy to change velocity accurately in large wide. Another widespread concern problem is launching the spinning stability projectile by railgun. This paper designed a new structure of additional rails to generate an unsymmetrical magnetic field to produce rotational torque in armature. The structure is simple and can control the rotation rate by linear changing the barrel parameters. The calculation formulas of interior ballistic are derived by Biot-Safar law. The important parameter is the deflection angle of the additional rails relative to the symmetry plane of main rail. The larger the angle, the greater the rotation torque generated in the armature. To maintain the flight stability of the projectile, the barrel structural parameters should be proportional to the projectile structural parameters. When changing the muzzle velocity, the rotation rate will also be the equal proportion change. So that the gyro stability is the same. The experiment proves that the railgun designed in this paper can launch the projectile to rotate. And the rotational projectile may not cause the transition or much arcs. This method expands the application of the railgun.

关键词： Ballistic control Railgun Rotation Spin-stabilized projectile

Evaluation of the infectivity,gene and antigenicity persistence of rotaviruses by free chlorine disinfection

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2011年第10期23卷 1691-1698页

作者： dan Li April Z. Gu Siyu Zeng wan Yang Miao He Hanchang Shi Environmental Simulation and Pollution Control （ESPC） State Key Joint Laboratory School of Environment Tsinghua University Beijing 100084 China Department of Civil and Environmental Engineering Northeastern University Boston MA 02115 USA

The effects of free chlorine disinfection of tap water and wastewater effluents on the infectivity, gene integrity and surface antigens of rotaviruses were evaluated by a bench-scale chlorine disinfection experiments. Plaque assays, integrated cell culture-quantitative RT- PCR （ICC-RT-qPCR）, RT-qPCR, and enzyme-linked immunosorbent assays （ELISA）, respectively, were used to assess the influence of the disinfectant on virus infectivity as well as genetic and antigenic integrity of simian rotavirus SA11 as a surrogate for human rotaviruses. The ICC-RT-qPCR was able to detect rotaviruses survival from chlorine disinfection at chlorine dose up to 20 mg/L （60 min contact）, which suggested a required chlorine dose of 5 folds （from 1 to 5 mg/L） higher than that indicated by the plaque assay to achieve 1.8 log10 reductions in tap water with 60 rain exposing. The VP7 gene was more resistant than the infectivity and existed at chlorine dose up to 20 mg/L （60 min contact）, while the antigencity was undetectable with chlorine dose more than 5 mg/L （60 min contact）. The water quality also impacted the inactivation efficiencies, and rotaviruses have a relatively higher resistant in secondary effluents than in the tap water under the same chlorine disinfection treatments. This study indicated that rotaviruses have a higher infectivity, gene and antigencity resistance to chlorine than that previously indicated by plaque assay only, which seemed to underestimate the resistance of rotaviruses to chlorine and the risk of rotaviruses in environments. Present results also suggested that re-evaluation of resistance of other waterborne viruses after disinfections by more sensitive infectivity detection method （such as ICC-RT-qPCR） may be necessary, to determine the adequate disinfectant doses required for the inactivation of waterborne viruses.

关键词： rotaviruses free chlorine disinfection infectivity genes antigenicity ICC-RT-qPCR