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Compressive behavior and microstructure of concrete mixed with natural seawater and sea sand

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Frontiers of Structural and Civil Engineering 2021年第6期15卷 1347-1357页

作者： Qinghai XIE Jianzhuang XIAO Kaijian ZHANG zhongling ZONG Department of Structural Engineering Tongji UniversityShanghai 200092China School of Civil and Ocean Engineering Jiangsu Ocean UniversityLianyungang 222005China

Noncorrosive reinforcement materials facilitate producing structural concrete with seawater and sea *** study investigated the properties of seawater and sea sand concrete(SSC),considering the curing age(3,7,14,21,28,60,and 150 d)and strength grade(C30,C40,and C60).The compressive behavior of SSC was obtained by compressive tests and digital image correction(DIC)*** electron microscope(SEM)and X-ray powder diffraction(XRD)methods were applied to understand the microstructure and hydration products of cement in *** revealed a 30%decrease in compressive strength for C30 and C40 SSC from 60 to 150 d,and a less than 5%decrease for C60 from 28 to 150 *** results revealed significant cracking and crushing from 80%to 100%of compressive *** images showed a more compact microstructure in higher strength *** patterns identified Friedel’s salt phase due to the chlorides brought by seawater and sea *** findings in this study can provide more insights into the microstructure of SSC along with its short-and long-term compressive behavior.

关键词： seawater and sea sand concrete compressive strength strain field microstructure hydration products

Feature Profile Evolution During Etching of SiO_2 in Radio-Frequency or Direct-Current Plasmas

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Plasma Science and Technology 2012年第1期14卷 64-70页

作者： ZHAO Zhanqiang DAI zhongling WANG Younian School of Physics and Optoelectronic Technology Dalian University of TechnologyDalian 116024China

We have developed a plasma etching simulator to investigate the evolution of pattern profiles in SiO2 material under different plasma conditions. This model focuses on energy and angular dependent etching yield （physical sputtering in this paper）, neutral and ion angular distributions, and reflection of ions or neutrals on the surface of a photoresist or SiO2. The effect of positive charge accumulation on the surface of insulated mask or SiO2 is studied and the charge accumulation contributes to a deflection of ion trajectory. The wafer profile evolution has been simulated using a cellular-automata-like method under radio-frequency （RF） bias and direct-current （DC） bias, respectively. On the basis of the critical role of angular distribution of ions or neutrals, the wafer profile evolution has been simulated for different variances of angles. Observed microtrenching has been well reproduced in the simulator. The ratio of neutrals to ions has been considered and the result shows that because the neutrals are not accelerated by an electric field, their energy is much lower compared with ions, so they are easily reflected on the surface of SiO2, which makes the trench shallower.

关键词： profile evolution RF bias reflection etching yield

Commercial Production of Tiger Puffer(Takifugu rubripes)in Winter Using a Recirculating Aquaculture System

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Journal of Ocean University of China 2017年第1期16卷 107-113页

作者： LIN zhongling WANG Hua YU Chunyan LV Fenghe LIU Hengming ZHANG Tao Engineering Research Center of Shellfish Culture and Breeding in Liaoning Province School of Fisheries and Life ScienceDalian Ocean UniversityDalian 116023P.R.China National Marine Environmental Monitoring Center Dalian 116023P.R.China School of Marine Science and Environment Technology Dalian Ocean UniversityDalian 116023P.R.China Dalian Tianzheng Industrial Corporation Limited Dalian 116011P.R.China

Tiger puffer(Takifugu rubripes) is a promising species for aquaculture production because of its high value and limited supply. However, in the north of China, using sea cages to culture this species in winter is hampered by the fact that the seawater temperature is extremely low. Here, a large scale commercial production of tiger puffer has been successfully realized using a recirculating aquaculture system(RAS) from 3 October 2012 to 31 May 2013. The RAS was comprised of nine culture tanks(total water volume 200 m3) and stocked with approximately a total of 14400 fish(initial mean weight 160 g). The tiger puffer was hand-fed at a rate of 0.7% of total body weight per day, and the feed conversion rate was(1.21 ± 0.3) kg kg-1. The recycle water in RAS was treated by a sieve bend screen, a foam fractionator, a submerged biofilter, an UV sterilizer and a submersible aerator. During the whole culture period, an excellent water quality control was achieved in RAS. At the end of this experiment, the survival rate of tiger puffer was more than 98%. The final tank densities averaged 31.2 kg m-3, and the final individual mean weight was 440 g.

关键词： Takifugu rubripes recirculating aquaculture system production water quality

Ti_(3)C_(2)T_(x)MXene wrapped,carbon-coated porous Si sheets for improved lithium storage performance

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Chinese Chemical Letters 2024年第2期35卷 617-621页

作者： Hui Cheng Yueming Liu zhongling Cheng Xianying Wang Na Huang Haijiao Zhang Institute of Nanochemistry and Nanobiology School of Environmental and Chemical EngineeringShanghai UniversityShanghai 200444China Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai 200062China Energy Materials Research Center AG Hydrogen Materials & Devices CAS Key Laboratory of Materials for Energy ConversionShanghai Institute of CeramicsChinese Academy of Sciences (SICCAS)Shanghai 200050China

Si-based materials have shown great potential as lithium-ion batteries(LIBs)anodes due to their natural reserves and high theoretical ***,the large volume changes during cycles and poor conductivity of Si lead to rapid capacity decay and poor cycling stability,ultimately limiting their commercial ***,we have skillfully utilized the microporous MCM-22 zeolite as the unique silicon source to produce porous Si(pSi)sheets by a simple magnesiothermic reduction,followed by a carbon coating and further Ti_(3)C_(2)T_(x)MXene assembly,obtaining the ternary pSi@NC@TNSs *** the design,porous Si sheets provide more active sites and shorten Li-ion transport paths for electrochemical *** N-doped carbon(NC)layer serves as a bonding layer to couple pSi and Ti_(3)C_(2)T_(x).The conductive network formed by 2D Ti_(3)C_(2)T_(x)and medium NC layer effectively enhances the overall charge transport of the electrode material,and helps to stabilize the electrode ***,the as-made pSi@NC@TNSs anode delivers an improved lithium storage performance,exhibiting a high reversible capacity of 925 mAh/g at 0.5 A/g after 100 *** present strategy provides an effective way towards high-performance Si-based anodes for LIBs.

关键词： Si anodes Ti_(3)C_(2)Ti_(x)MXene Porous structure Interfacial assembly Lithium-ion batteries

Finite Element Simulations of the Localized Failure and Fracture Propagation in Cohesive Materials with Friction

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 997-1015页

作者： Chengbao Hu Shilin Gong Bin Chen zhongling Zong Xingwang Bao Xiaojian Ru Department of Civil Engineering Hangzhou City UniversityHangzhou310015China Zhejiang Engineering Research Center of Intelligent Urban Infrastructure Hangzhou310015China Key Laboratory of Safe Construction and Intelligent Maintenance for Urban Shield Tunnels of Zhejiang Province Hangzhou310015China School of Civil and Ocean Engineering Jiangsu Ocean UniversityLianyungang222005China Institute of Municipal Engineering Hangzhou Shangcheng District Municipal Engineering Group Co.Ltd.Hangzhou310016China

Strain localization frequently occurs in cohesive materials with friction(e.g.,composites,soils,rocks)and is widely recognized as a fundamental cause of progressive structural ***,achieving high-fidelity simulation for this issue,particularly concerning strong discontinuities and tension-compression-shear behaviors within localized zones,remains significantly *** response,this study introduces an integrated algorithmwithin the finite element framework,merging a coupled cohesive zone model(CZM)with the nonlinear augmented finite elementmethod(N-AFEM).The coupledCZMcomprehensively describes tension-compression and compressionshear failure behaviors in cohesive,frictional materials,while the N-AFEM allows nonlinear coupled intraelement discontinuities without necessitating extra nodes or nodal *** CZM validation using existing experimental data,this integrated algorithm was utilized to analyze soil slope failure mechanisms involving a specific tensile strength and to assess the impact of mechanical parameters(e.g.,tensile strength,weighting factor,modulus)in soils.

关键词： FEM analysis strong discontinuity nonlinear soil rupture cohesive zone model tension-compression-shear coupling