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Synthesis and evaluation of cationic flocculant P(DAC-PAPTAC-AM) for flocculation of coal chemical wastewater

Journal of Environmental Sciences 2021年第1期33卷 239-248页

作者： Wenquan sun Shengbao Zhou yongjun sun Yanhua Xu College of Urban Construction Nanjing Tech UniversityNanjing 211800China School of Environmental Sciences and Engineering Nanjing Tech UniversityNanjing 211816China

In this study,a high-efficiency cationic flocculant,P(DAC-MAPTAC-AM),was successfully prepared using UV-induced polymerization *** monomer Acrylamide(AM):Acryloxyethyl Trimethyl ammonium chloride(DAC):methacrylamido propyl trimethyl ammonium chloride(MAPTAC)ratio,monomer concentration,photoinitiator concentration,urea content,and cationic monomer DAC:MAPTAC ratio,light time,and power of highpressure mercury lamp were *** characteristic groups,characteristic diffraction peaks,and characteristic proton peaks of P(DAC-MAPTAC-AM)were confirmed by fourier transform infrared spectroscopy(FTIR),X-Ray diffraction(XRD),1H nuclear magnetic resonance spectrometer(1H NMR),and scanning electron microscopy(SEM).The effects of dosage,pH value,and velocity gradient(G)value on the removal efficiencies of turbidity,COD,ammonia nitrogen,and total phenol by poly aluminum ferric chloride(PAFC),P(DACMAPTAC-AM),and PAFC/P(DAC-MAPTAC-AM)in the flocculation treatment of coal chemical wastewater were *** showed that the optimal conditions for the flocculation of coal chemical wastewater using P(DAC-MAPTAC-AM)alone are as follows:dosage of 8-12 mg/L,G value of 100-250 s^-1,and pH value of *** optimal dosage of PAFC is 90-150 mg/L with a pH of *** optimal dosage for PAFC/P(DAC-MAPTAC-AM)is as follows:PAFC dosage of 90-150 mg/L,P(DAC-MAPTAC-AM)dosage of 8-12 mg/L,and pH range of *** P(DAC-MAPTAC-AM)was used alone,the optimal removal efficiencies of turbidity,COD,ammonia nitrogen,and total phenol were 81.0%,35.0%,75.0%,and 80.3%,*** has good tolerance to wastewater pH and good pH ***,the flocculation treatment of coal chemical wastewater using the PAFC/P(DAC-MAPTAC-AM)compound also exhibits excellent resistance and buffering capacity.

关键词： Coal chemical wastewater Cationic flocculant Flocculation Coagulation Pretreatment

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NON-LOCAL MODELING ON MACROSCOPIC DOMAIN PATTERNS IN PHASE TRANSFORMATION OF NiTi TUBES

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Acta Mechanica Solida Sinica 2009年第5期22卷 407-417页

作者： yongjun He Qingping sun Department of Mechanical Engineering The Hong Kong University of Science and Technology Hong Kong China

Recent experiments revealed many new phenomena of the macroscopic domain patterns in the stress-induced phase transformation of a superelastic polycrystalline NiTi tube during tensile loading. The new phenomena include deformation instability with the formation of a helical domain, domain topology transition from helix to cylinder, domain-front branching and loading-path dependence of domain patterns. In this paper, we model the polycrystal as an elastic continuum with nonconvex strain energy and adopt the non-local strain gradient energy to account for the energy of the diffusive domain front. We simulate the equilibrium domain patterns and their evolution in the tubes under tensile loading by a non-local Finite Element Method （FEM）. It is revealed that the observed loading-path dependence and topology transition of do- main patterns are due to the thermodynamic metastability of the tube system. The computation also shows that the tube-wall thickness has a significant effect on the domain patterns： with fixed material properties and interfacial energy density, a large tube-wall thickness leads to a long and slim helical domain and a severe branching of the cylindrical-domain front.

关键词： martensitic phase transition macroscopic domain patterns NiTi polycrystalline tubes non-local and nonconvex elasticity tube-wall thickness effect metastability and instability

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Mechanical design and analysis of a novel variable stiffness actuator with symmetrical pivot adjustment

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Frontiers of Mechanical Engineering 2021年第4期16卷 711-725页

作者： Yiwei LIU Shipeng CUI yongjun sun State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China

The safety of human-robot interaction is an essential requirement for designing collaborative ***,this paper aims to design a novel variable stiffiiess actuator(VSA)that can provide safer physical human-robot interaction for collaborative *** A follows the idea of modular design,mainly including a variable stiffiiess module and a drive *** variable stiffiiess module transmits the motion from the drive module in a roundabout maimer,making the modularization of VS A *** the key component of the variable stiffiiess module,a stiffness adjustment mechanism with a symmetrical structure is applied to change the positions of a pair of pivots in two levers linearly and simultaneously,which can eliminate the additional bending moment caused by the asymmetric *** design of the doubledeck grooves in the lever allows the pivot to move freely in the groove,avoiding the geometric constraint between the ***,the VSA stiffiiess can change from zero to infinity as the pivot moves from one end of the groove to the *** facilitate building a manipulator in the future,an expandable electrical system with a distributed structure is also *** calibration and control experiments are performed to evaluate the physical performance of the designed *** results show that the VSA stiffiiess is close to the theoretical design ***,the VSA with a proportional-derivative feedback plus feedforward controller exhibits a fast response for stiffiiess regulation and a good performance for position tracking.

关键词： variable stiffiiess actuator variable stiffness module drive module symmetrical structure doubledeck grooves expandable electrical system

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Codebook selected beamforming algorithm for multiuser MIMO systems

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Journal of Systems Engineering and Electronics 2011年第1期22卷 170-174页

作者： Wengang Li Kechu Yi Daixian Zhu yongjun sun State Key Laboratory of Integrated Service Networks Xidian University Xi'an 710071 R R. China Communication and Information Engineering College Xi'an University of Science and Technology Xi'an 710054 P. R. China

For reducing the inter-user interference in multi-user multiple-input multiple-output（MU-MIMO） wireless communication systems,e.g.,MIMO-orthogonal frequency division multiplexing（MIMO-OFDM） systems,it is often desirable to the complex preprocessing at the *** paper proposes a multi-user beamforming algorithm with sub-codebook *** on the minimal leakage criterion,the codebook selection,limited feed-forward and minimum mean square error（MMSE） detection are combined in the proposed *** avoids the complex channel matrix decomposition and ***,the computational complexity at the transmitter is significantly *** results show that the proposed algorithm performs better than existing beamforming algorithms.

关键词： multi-user multiple-input multiple-output(MU-MIMO) linear beamforming co-channel interference(CCI) minimum mean square error(MMSE).

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A novel coordinated control for NZEB clusters to minimize their connected grid overvoltage risks

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Building Simulation 2022年第10期15卷 1831-1848页

作者： Yelin Zhang Norman Chung Fai Tse Haoshan Ren yongjun sun Division of Building Science and Technology City University of Hong KongKowloonHong KongChina

The increasing applications of net-zero energy buildings (NZEBs) will lead to more frequent and larger energy interactions with the connected power grid, thereby being able to result in severe grid overvoltage risks. Control optimization has been proven effective to reduce such risks. Existing controls have oversimplified the overvoltage quantification by simply using the aggregated power exchanges to represent the connected grid overvoltages. Ignoring the complex voltage influences among the grid nodes, such oversimplification can easily result in low-accuracy impact evaluations of the NZEB-grid energy interactions, thereby causing non-optimal/unsatisfying overvoltage mitigations. Therefore, this study proposes a novel coordinated control method in which a power-distribution-network model has been adopted for more accurate overvoltage quantification. Meanwhile, the battery operations of individual NZEBs are iteratively coordinated using a sequential optimization approach for achieving the global optimum with substantially reduced computation complexity. For verifications, the proposed coordinated control has been systematically compared with an uncoordinated control and a conventional coordinated control in grid overvoltage minimization. The study results show that the overvoltage improvements can reach 23.5% and 12.3% compared with the uncoordinated control and the conventional coordinated control, respectively. The reasons behind the improvements have also been analyzed in detail. The proposed coordinated control can be used in practice to improve NZEB-clusters’ grid friendliness.

关键词： net-zero energy building coordinated control optimization,genetic algorithm overvoltage quantification grid friendliness

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Heavy metal removal from aqueous solutions by chitosan-based magnetic composite flocculants

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Journal of Environmental Sciences 2021年第10期33卷 22-32页

作者： Xuefeng Xiao Yuanyuan Yu yongjun sun Xing Zheng Aowen Chen College of Urban Construction Nanjing Tech UniversityNanjing 211800China Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong Kong 999077China

In this study,three magnetic flocculants with different chelating groups,namely,carboxymethyl chitosan-modified Fe_(3)O_(4)flocculant(MC),acrylamide-grafted magnetic carboxymethyl chitosan flocculant(MCM),and 2-acrylamide-2-methylpropanesulfonic acid copolyacrylamide-grafted magnetic carboxymethyl chitosan flocculant(MCAA)were prepared,synthesized,and characterized by photopolymerization *** were applied to the flocculation removal of Cr(Ⅲ),Co(Ⅱ),and Pb(Ⅱ).The effect of flocculation condition on the removal performance of Cr(Ⅲ),Co(Ⅱ),and Pb(Ⅱ)was *** results show that the three magnetic carboxymethyl chitosan-based flocculants have been successfully prepared with good magnetic induction *** results show that the removal rates of MC,MCM,and MCAA on Cr(Ⅲ)are 51.79%,82.33%,and 91.42%,respectively,under the conditions of 80 mg/L flocculant,pH value of 6,reaction time of 1.5 hr,G value of 200 s^(-1),and precipitation magnetic field strength of 120 *** removal rates of Co(Ⅱ)by MC,MCM,and MCAA are 54.33%,84.99%,and 90.49%,*** removal rates of Pb(Ⅱ)by MC,MCM,and MCAA are 61.54%,91.32%,and 95.74%,*** shows good flocculation performance in composite heavy metal-simulated *** magnetic carboxymethyl chitosan-based flocculant shows excellent flocculation performance in removing soluble heavy *** research provides guidance and ideas for the development of efficient and low-cost flocculation technology to remove heavy metals in wastewater.

关键词： Flocculant Carboxymethyl chitosan Magnetic flocculants Heavy metal Flocculation

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Generic load regulation strategy for enhancing energy efficiency of chiller plants

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Building Simulation 2024年第8期17卷 1273-1287页

作者： Hang Wan Yuyang Gong Shengwei Wang yongjun sun Tao Xu Gongsheng Huang Department of Architecture and Civil Engineering City University of Hong KongHong KongChina Department of Building Environment and Energy Engineering Hong Kong Polytechnic UniversityHong KongChina School of Civil Engineering Guangzhou UniversityGuangzhouChina Shenzhen Research Institute of City University of Hong Kong ShenzhenChina

In many chiller plants,high coefficient of performance(COP)is only achieved at a few favorable part load ratios(PLRs),while the COP is low at many other non-favorable *** address this issue,this study proposes a generic load regulation strategy that aims to maintain chiller plants operating at high COP,particularly under non-favorable *** is achieved by incorporating thermal energy storage(TES)units and timely optimizing the charging and discharging power of the integrated TES *** optimal charging and discharging power is determined by solving a dynamic optimization problem,taking into account the performance constraints of the TES units and the chiller *** provide an overview of the energy-saving potential of the proposed strategy,a comprehensive analysis was conducted,considering factors such as building load profiles,COP/PLR curves of chillers,and attributes of the TES *** analysis revealed that the proposed load regulation strategy has the potential to achieve energy savings ranging from 5.7%to 10.8%for chiller plants with poor COPs under unfavorable PLRs,particularly in buildings with significant load variations.

关键词： load regulation thermal energy storage chiller plants building energy efficiency

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Effect of Co-Culture of Chinese Shrimp(Fenneropenaeus chinensis) and Sea Cucumber(Apostichopus japonicus Selenka) on Pond Environment

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Journal of Ocean University of China 2016年第5期15卷 905-910页

作者： YU Haibo GAO Qinfeng DONG Shuanglin sun yongjun WANG Fang Key Laboratory of Mariculture of Ministry of Education Ocean University of China College of Animal Science and Technology Northwest A&F University Research Office Homey Group International Inc.

Monoculture of sea cucumber(pond S) and polyculture of shrimp with sea cucumber(pond SS) were established to evaluate the effect of shrimp on the environmental conditions of sea cucumber farming pond. Contributions of sediment organic matter(SOM2) resuspended from benthic sediment and the suspended particulate organic matter(SPOM) deposited from the water column to the precipitated organic matter(SOM1) collected with sediment traps were estimated with carbon stable isotope analysis. The results showed that the levels of SPOM and SOM2 in pond SS significantly decreased in comparison with those in pond S at the end of experiment(P < 0.05), indicating that co-culturing shrimp in sea cucumber farming pond could purify the farming water. Carbon stable isotope analysis showed that the proportion of SOM2 in SOM1 in pond SS(84.97% ± 0.38%) was significantly lower than that in pond S(95.20% ± 0.30%)(P < 0.05), suggesting that the resuspension of organic matter from benthic sediment into overlying water was reduced in polyculture pond. In contrast, the proportion of SPOM in SOM1 in pond SS(15.03% ± 0.38%) was significantly higher than that in pond S(4.80% ± 0.30%)(P < 0.05), indicating that the sedimentation of SPOM from water column was enhanced in pond SS owing to the biodeposition effect of shrimp.

关键词： shrimp cucumber farming suspended particulate isotope sedimentation aquaculture seawater salinity

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Strategies for the Interaction Design of Landscape Environment in the Information Age

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Journal of Landscape Research 2022年第6期14卷 9-13页

作者： sun yongjun PAN Mingshuai North China University of Technology Beijing 100144China

The vigorous development of science and technology prompts people to put forward more diversified requirements for the built environment. The emergence of interactive landscape provides a new method for the renewal and development of landscape environment, and becomes a new way to deal with the relationship between human and landscape environment. In this paper, from the perspective of interactivity, the application achievements of interactive environmental design were analyzed from three aspects of interactive relationship, interactive forms and landscape functions, and the development space and great potential of interactivity theory in environmental design were discussed to provide reference for subsequent relevant research.

关键词： Interaction design Perception Interactive landscape

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Impact of resveratrol on the expression of apoptosis related gene survivin and bax in human cancer cells

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The Chinese-German Journal of Clinical Oncology 2009年第8期8卷 467-470页

作者： yongjun Li Xiaohui sun Rui Zhang Department of Laboratory The Second Hospital of Hebei Medical University Shijiazhuang 050000 China

Objective： We explored the mechanism of apoptosis in human esophageal cancer Ecal09 cells by resveratrol. Methods： The suppressive ratio of resveratrol on Ecal09 cells proliferation was evaluated by MTT colorimetric assay and morphology was observed by transmission electron microscope. The expression of survivin and bax was analyzed by RT-PCR and Flow Cytometry （FCM）. Results： Resveratrol inhibited the growth of Ecal09 calls in a dose-and time-dependent man- ner, and the suppressive ratio arrived at 76.42%. Morphological apoptosis could be observed after treated with *** bulk of some drug-treated cells turned small and the nuclear chromatin became condensed and rnarginated. The results determined by RT-PCR and FCM showed that resveratrol could down-regulate surviving, while up-regulate bax. Conclusion： Resveratrol could induce the apoptosis of human esophageal cancer Ecal09 cells, and its possible molecular mechanisms might be related to modulation the expression of survivin and bax.

关键词： resveratrol esophageal neoplasms Eca109 cell cell apoptosis survivin bax

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