检索结果-南通市图书馆

Journal of Ocean University of China 2024年第1期23卷 23-32页

作者： WU De’an LI Xin WANG Yigang College of Harbor Coastal and Offshore EngineeringHohai UniversityNanjing 210098China tianjin research institute For water transport engineering Tianjin 300456China

To study the stratified stability of a water column in the North Passage of the Yangtze River Estuary,a numerical model of the hydrodynamics of this estuary is established using the EFDC *** the basis of EFDC results,this paper derives and pro-vides the discriminative index of water body stability caused by salinity and analyzes the along-range variation in water body strati-fication stability in the North Passage of the Yangtze River Estuary and the periodic variation at a key location(bend area)based on the simulation results of the numerical *** work shows that the water body in the bend area varies between mixed and strati-fied types,and the vertical average flow velocity has a good negative correlation with the differential velocity between the surface and bottom layers of the water *** model simulation results validate the formulae for the stratified stability discriminant during spring tides.

关键词： Yangtze Estuary North Passage EFDC model stratification stability salinity distribution

Linkage between riverbed scouring or deposition and the evolution of central bars:Case study in the Yangzhong reach of the Yangtze River

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2024年第7期34卷 1323-1347页

作者： YANG Yunping ZHANG Xiabo FENG Xiaoxiang HAN Jianqiao WANG Jianjun ZHU Yude YANG Yanhua tianjin research institute for water transport engineering Ministry of TransportTianjin300456China College of Harbour Coastal and Offshore EngineeringHohai UniversityNanjing210098China Northwest Agriculture and Forestry University YanglingShaanxi712199China

Understanding the relationship between unbalanced riverbed scouring or deposition and the evolution of central bars in natural conditions and human activity is useful for river regime control and waterway improvement *** this end,we utilized the Yangzhong reach in the lower reaches of the Yangtze River as a case study and evaluated runoff,sediment content,and topographical data measured over the past 70 years(1951–2021).With the decrease in the amount of incoming sediment in the river basin,the Yangzhong reach exhibited a continuous state of *** cumulative riverbed scouring volumes of the low-water and flood channels from 1981 to 2021 were 3.97×10^(8)and 4.14×10^(8)m^(3),respectively,with the riverbed scouring volume of the low-water channel accounting for 95.9%of that of the flood *** quasi-natural runoff–sediment conditions,the evolution of the central bars in the Yangzhong reach was highly correlated with the amount of scouring or *** particular,the Luochengzhou reach could be characterized as a meandering river with scouring on concave riverbanks and deposition on convex *** the context of reduced incoming sediment,the beach area of the Yangzhong reach decreased by approximately 9.9%(from 2003 to 2021)and the central bars of the straight section areas ***,following operation of the Three Gorges Reservoir,both the Luocheng central bar and Jiangyin beach areas could be characterized as meandering rivers with convex riverbanks and *** the quasi-natural period before the implementation of the waterway improvement project,the trend of high scouring intensity and increased fluid diversion ratio in the right branch of the Luocheng central bar was in accordance with the law that the short branch of the length is in a developing state under the condition of decreasing river sediment *** the control of riverbank protection and the construction of waterway improvement projects in the Yangzhong

关键词： riverbed scouring or deposition beach morphology linkage relationship causal analysis tidal reach Yangtze River

Coupled Cross-Flow/in-Line Vortex-Induced Vibration Responses of a Catenary-Type Riser Subjected to Uniform Flows

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2024年第5期23卷 1202-1212页

作者： LI Xiaomin CAO Xi LI Fuheng YANG Zhiwen College of engineering Ocean University of ChinaQingdao 266404China College of Hydrodynamic engineering Tianjin Research Institute for Water Transport EngineeringM.O.TTianjin 300456China

A three-dimensional numerical scheme was developed to investigate the vortex-induced vibration(VIV)of a catenary-type riser(CTR)in the in-line(IL)and cross-flow(CF)*** using the vector form intrinsic finite element method,the CTR was discretized into a finite number of spatial particles whose motions satisfy Newton’s second *** Van der Pol oscillator was used to simulate the effect of vortex *** coupling equations of structural vibration and wake oscillator were solved using an explicit central differential *** numerical model was verified with the published *** VIV characteristics of the CTR subjected to uniform flows,including displacement,frequency,standing wave,traveling wave,motion trajectory,and energy transfer,were studied *** numerical results revealed that the multimode property occurs in the CF-and IL-direction VIV responses of the *** increase in the flow velocity has slight effects on the maximum VIV *** to structural nonlin-earity,the double-frequency relationship in the CF and IL directions is rarely ***,the vibration trajectories display the shape of an inclined elliptical ***,the negative energy region is inconspicuous under the excitation of the uniform flow.

关键词： vortex-induced vibration vector form intrinsic finite element catenary-type riser wake oscillator equation

Composition characterization and transformation mechanism of dissolved organic phosphorus in wastewater treatment using 31P NMR spectroscopy

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & engineering 2024年第3期18卷 103-113页

作者： Yuting Zhang Wei Shang SoonThiam Khu Xingcan Zheng Yongli Sun Pengfeng Li Miao Gu Wen-an Zhang Huanmei Ma National engineering research Center For Urban water&Wastewater North China Municipal Engineering Design&Research Institute Co.Ltd.Tianjin 300381China School of Environment Science&engineering Tianjin UniversityTianjin 300350China

The migration and transformation of phosphorus components in wastewater treatment plants(WWTPs)play a crucial role in the convergence and circulation of ***,the composition and variation of dissolved organic phosphorus(DOP)in WWTPs were unclear because of its complex nature,hindering its efficient *** this study,the DOP species and their transformation during the treatment process in WWTP were comprehensively ***,two enrichment methods were assessed for their effectiveness at facilitating wastewater analysis:lyophilization and aluminum salt *** salt precipitation was found to be better because its application allowed 31P nuclear magnetic resonance(31P NMR)spectroscopy to identify more species in the secondary effluent:orthophosphate(Ortho-P)(81.1%–89.3%of the dissolved total phosphorus),pyrophosphates(Pyro-P)(0%–2.3%),orthophosphate monoesters(Mono-P)(7.0%–10.77%),orthophosphate diesters(Di-P)(1.0%–2.96%),and phosphonate(Phos-P)(1.7%–5.16%).Furthermore,the variation and transformation mechanism of phosphorus,particularly those of DOP,during the entire sewage-treatment process were *** the treatment steps,biological treatment combined tertiary treatment achieved better DOP removal ***,biological treatment mainly removed Mono-P and Di-P with removal efficiencies of 33.3%and 41.7%compared with the effluent of the grit ***-P has higher bioavailability and is more easily converted and utilized by microorganisms than ***,Phos-P,with low bioavailability,was hardly utilized by microorganisms,which showed only 18.4%removal efficiency in biological *** tertiary treatment,coagulation process exhibited higher removal ability of Ortho-P(69.1%)and partial removal efficiencies of DOP,resulting in an increase in the DOP proportion in *** addition,Phos-P could not be effectively removed through the biological treatment and was only partially reduced via the adsorption pro

关键词： Municipal wastewater Dissolved organic phosphorus Composition Transformation 31P nuclear magnetic resonance

Experimental Study on Hydrodynamic Load Characteristics for A Typical Cross-Section of A Submerged Floating Tunnel

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

China Ocean engineering 2024年第5期38卷 893-903页

作者： ZHANG Hong-qian YANG Zhi-wen LI Shao-wu YUAN Chun-guang ZHANG Hua-qing National engineering research Center for Port Hydraulic Construction Technology Tianjin University National engineering research Center for Port Hydraulic Construction Technology Tianjin Research Institute for Water Transport EngineeringM.O.T.

The typical cross-sectional form of a submerged floating tunnel plays a significant role in the dynamic response of the tunnel itself,which directly affects the overall *** this work,a series of experiments involving wave action on a submerged floating tube cross section is reported to study its hydrodynamic load *** typical cross section tube cylinders,circular and rectangular,are *** are carried out in a wave flume with waves of relatively low Keulegan-Carpenter（KC） *** relative depths of submergence of 0,0.25 and 0.5are *** measured wave forces in regular waves are used to analyze the horizontal force,vertical force and torque,and then the drag coefficient（Cd） and inertia coefficient（Cm） are *** results show that the drag coefficients at low KC numbers are large and decrease sharply with increasing KC *** inertial coefficient Cmvalues in the vertical direction are about 70% larger than those in the horizontal *** an increase in aspect ratio（the ratio of the height to width of the structure）,the ratio of inertia coefficient in the horizontal direction to that in the vertical direction increases *** inertia force coefficient is very sensitive to the submerged water depth and aspect *** existing results may overestimate the actual force value.

关键词：

Atomically Substitutional engineering of Transition Metal Dichalcogenide Layers for Enhancing Tailored Properties and Superior Applications

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第5期16卷 248-284页

作者： Zhaosu Liu Si Yin Tee Guijian Guan Ming‑Yong Han institute of Molecular Plus Tianjin UniversityTianjin 300072People’s Republic of China institute of Materials research and engineering A*STARSingapore 138634Singapore

Transition metal dichalcogenides(TMDs)are a promising class of layered materials in the post-graphene era,with extensive research attention due to their diverse alternative elements and fascinating semiconductor *** MX2 layers with different metal and/or chalcogen elements have similar structural parameters but varied optoelectronic properties,providing opportunities for atomically substitutional engineering via partial alteration of metal or/and chalcogenide atoms to produce ternary or quaternary *** resulting multinary TMD layers still maintain structural integrity and homogeneity while achieving tunable(opto)electronic properties across a full range of composition with arbitrary ratios of introduced metal or chalcogen to original counterparts(0–100%).Atomic substitution in TMD layers offers new adjustable degrees of freedom for tailoring crystal phase,band alignment/structure,carrier density,and surface reactive activity,enabling novel and promising *** review comprehensively elaborates on atomically substitutional engineering in TMD layers,including theoretical foundations,synthetic strategies,tailored properties,and superior *** emerging type of ternary TMDs,Janus TMDs,is presented specifically to highlight their typical compounds,fabrication methods,and potential ***,opportunities and challenges for further development of multinary TMDs are envisioned to expedite the evolution of this pivotal field.

关键词： Transition metal dichalcogenides Atomic substitution Tailored structure Tunable bandgap Enhanced applications

Investigation of Ce/BEA as a passive NO_(x)adsorber:*** occurrences of cerium and adsorption behavior

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第7期42卷 1265-1271,I0003页

作者： Minghui Yu Yiying Ding Xiaojie Yu Siwei Yan Meiqing Shen Jianqiang Wang Jun Wang Gurong Shen School of Materials Science and engineering Tianjin UniversityTianjin300350China School of Chemical engineering and Technology Tianjin UniversityTianjin300350China National Rare Earth Catalysis research institute Dongying257000China

Ce/BEA has great potential as a passive NO_(x)absorber(PNA)to reduce the NO_(x)emissions during the cold start phase especially in diesel engine for its high resistance to CO and suitable NO_(x)desorption temperature ***,as a novel material,its physical and chemical properties still remain *** this work,Ce/BEA was synthesized by ion-exchange method to identify the active species in NO_(x)adsorption,compared with aggregated Ce species in Ce/SiAlO_(x) prepared by impregnation method.X-ray diffraction(XRD),high resolution-transmission electron microscopy(HR-TEM)and aberration-corrected-scanning transmission electron microscopy(AC-STEM)were performed to confirm the isolated single atom formation of Ce species in Ce/***-vis diffraction reflection spectra(DRS)and X-ray photoelectron spectroscopy(XPS)were conducted to find the difference of chemical environment between the isolated Ce species and aggregated *** performance evaluation and temperature programmed reduction of hydrogen(H_(2)-TPR)results show the high NO_(x)storage capacity and active oxygen species quantity in Ce/*** is also found that the main NO_(x)adsorption species are Ce^(4+)-O^(∗)rather than Ce^(3+).NO_(x)-diffuse reflectance infrared Fourier transform spectroscopy(NO_(x)-DRIFTS)confirms that the bidentate nitrite species are the critical NO_(x)adsorption intermediates and the conception of NO_(x)adsorption and desorption processes is proposed.

关键词： Passive NO_(x)absorber Ce/BEA Isolated Ce species Rare earths

Investigation of Ce/BEA as a passive NO_(x)adsorber:*** aging deactivation mechanism

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第8期42卷 1524-1530,I0004页

作者： Yiying Ding Minghui Yu Xiaojie Yu Meiqing Shen Jianqiang Wang Jun Wang Gurong Shen School of Chemical engineering and Technology Tianjin UniversityTianjin300350China School of Materials Science and engineering Tianjin UniversityTianjin300350China National Rare Earth Catalysis research institute Dongying257000China

Ce/BEA has the potential to be applied as a novel passive NO_(x)absorber(PNA)in the after-treatment of vehicles due to its considerable NO_(x)storage ***,as a vehicle exhaust after-treatment material,it must withstand the test of long-term hydrothermal *** work examined the deactivation mechanism of Ce/BEA during hydrothermal aging.3.0 wt%Ce/BEA was prepared using the ionexchange method,and then subjected to hydrothermal treatment at 650℃with 10%H_(2)O for 1-12 h to obtain samples with different aging *** comparison,the H-BEA support was aged under the same ***-Emmett-Teller(BET)method,X-ray diffraction(XRD),NH_(3)temperature programmed reduction(NH_(3)-TPD),^(27)Al MAS nuclear magnetic resonance(^(27)Al MAS NMR),H_(2)temperature programmed reduction(H_(2)-TPR),and high resolution-transmission electron microscopy(HR-TEM)were performed to characterize the changes in PNA performance,structure,Ce species,and *** HR-TEM and H_(2)-TPR results show that CeO_(x)particles appear after hydrothermal aging,which results from the detachment and aggregation of active Ce *** on the^(27)Al MAS NMR results,we conclude that BEA zeolite dealumination leads to the loss of acidic sites and the transformation of active Ce species on the acidic sites into the less active CeO_(x).This is the primary reason for the hydrothermal aging deactivation of Ce/BEA.

关键词： Passive NO_(x)adsorber Ce/BEA Hydrothermal aging CeO_(x) Dealumination Rare earths

High adsorption selectivity of activated carbon and carbon molecular sieve boosting CO_(2)/N_(2) and CH_(4)/N_(2) separation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical engineering 2024年第3期67卷 282-297页

作者： Siang Chen Wenling Wu Zhaoyang Niu Deqi Kong Wenbin Li Zhongli Tang Donghui Zhang The research Center of Chemical engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

Flue gas and coal bed methane are two important sources of greenhouse *** swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is *** this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and N_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 *** experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric *** the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>N_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is N_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-N_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular ***,the adsorption selectivity of CH_(4)/N_(2) and CO_(2)/N_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) *** study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.

关键词： Activated carbon Carbon molecular sieve Adsorbent evaluation Adsorption equilibrium and kinetics Heat of adsorption Selectivity

Optimization of biofuel supply chain integrated with petroleum refineries under carbon trade policy

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and engineering 2024年第3期18卷 113-122页

作者： Wenhui Zhang Yiqing Luo Xigang Yuan Chemical engineering research Center School of Chemical Engineering and TechnologyTianjin UniversityTianjin300350China State Key Laboratory of Chemical engineering Tianjin UniversityTianjin300350China

The use of fossil fuels results in significant carbon dioxide *** have been increasingly adopted as sustainable alternatives to fossil fuel to address this environmental *** petroleum refineries into biofuel supply chains is an effective approach to mitigating greenhouse gas emissions and improving environmental *** this study,an integrated supply chain optimization framework was established,considering the carbon trade *** addition,a mixed-integer nonlinear programming model was developed to optimize the selection of biomass suppliers,construction of pretreatment plants and biorefineries,integration of petroleum refineries,and selection of transportation routes with the objective of minimizing the total annual *** example is presented to illustrate the applicability of the *** optimization results show that integrating petroleum refineries into biofuel supply chains effectively mitigates carbon *** trade policies can have a direct impact on the total annual cost and carbon emissions of the supply chain.

关键词： renewable energy biofuel supply chain carbon trade policy