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Journal of Iron and Steel Research(International) 2023年第4期30卷 795-807页

作者： Cheng-song Liu Wei Liu Hua Zhang Hong-wei Ni The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081HubeiChina

transformation mechanisms and reaction kinetics for formation of nanoscale inclusions in as-built 316L stainless steel produced by laser beam powder bed fusion(LB-PBF)during subsequent isothermal heating process were investigated and clarified experimentally and theoretically.The resulting changes in morphologies,size distributions,number densities,and chemical compositions of the inclusions were measured and discussed,along with microstructure and texture of the steel.The results showed that with increasing isothermal heating time and temperature,the columnar grains in the as-built LB-PBF 316L stainless steel transformed into equiaxed grains,which grew gradually and exhibited a large number of twins in the FCC structure.During isothermal heating,the reaction of Si in the steel with MnO–Cr_(2)O_(3)in the nanoscale inclusion resulted in a transformation from the homogeneous oxide MnO–SiO_(2)–Cr_(2)O_(3)to an inclusion with an obvious core–shell structure,and the core part was eventually rich in Si and the shell part was predominantly rich in Mn and Si,depending on the heating temperature and time.An Ostwald ripening model used for predicting the growth of nanoscale inclusions during isothermal heating verified that the observed effects of isothermal heating time and temperature were predicted for Si diffusion control.

关键词： 316L stainless steel Laser beam powder bed fusion Nanoscale inclusion Isothermal heating transformation

transformation of sulfamethazine during the chlorination disinfection process: transformation,kinetics, and toxicology assessment

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Journal of Environmental Sciences 2019年第2期31卷 48-56页

作者： Yunjia Yang Jiachen Shi Yi Yang Jie Yin Jing Zhang Bing Shao Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning Beijing Center for Disease Prevention and Control Beijing Research Center for Preventive Medicine

Various disinfection byproducts(DBPs) form during the process of chlorination disinfection,posing potential threats to drinking water safety and human health. Sulfamethazine(SMT),the most commonly used and frequently detected veterinary antibiotic, was investigated in detail with regard to its transformation and kinetics in reactions with free available chlorine(FAC). Using liquid chromatography coupled to quadrupole time-of-flight tandem mass spectrometry, several DBPs were identified based on different confidence levels, and a variety of reaction types, including desulfonation, S–N cleavage, hydroxylation, and chlorine substitution, were proposed. The kinetic experiments indicated that the reaction rate was FAC-and pH-dependent, and SMT exhibits low reactivity toward FAC in alkaline conditions. The DBPs exhibited a much higher acute toxicity than SMT, as estimated by quantitative structure activity relationship models. More importantly, we observed that the FAC-treated SMT reaction solution might increase the genotoxic potential due to the generation of DBPs. This investigation provides substantial new details related to the transformation of SMT in the chlorination disinfection process.

关键词： LC-QTOF Sulfamethazine transformation products Chlorination Toxicity

transformation optics based on metasurfaces

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Science Bulletin 2019年第12期64卷 793-796页

作者： Chong Sheng Hui Liu Shining Zhu National Laboratory of Solid State Microstructures and School of Physics Collaborative Innovation Center of Advanced Microstructures Nanjing University

The development of transformation optics and metamaterials provides a new paradigm for efficiently controlling electromagnetic waves. It is well known that the metamaterial is a novel artificial material with periodic structure, and the unit geometric size and distance between the units are much smaller than the working wavelength. Therefore, for an electromagnetic wave, a macroscopic system comprising these sub-wavelength units can be regarded as a novelty artificial material with a different permittivity, permeability and refractive index compared to the original material. Furthermore, these electromagnetic parameters of the artificial material can be freely manipulated by modifying their unit structure, especially for a material that does not exist in nature. Among these materials, negative refractive index materials have been widely reported. For a negative refractive index material, when light is incident on its interface, the incident and refracted light are distributed on the same side of the surface normal, rather than on both sides as typical materials do. However, the field of transformation optics proposes the concept that the propagation of an electromagnetic wave in curved spacetime is identical in inhomogeneous and anisotropic optical mediums.

关键词： transformation optics metamaterials provides efficiently controlling electromagnetic waves

A review on the transformation of birnessite in the environment:Implication for the stabilization of heavy metals

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Journal of Environmental Sciences 2024年第5期139卷 496-515页

作者： Miao Shi Qingzhu Li Qingwei Wang Xuelei Yan Bensheng Li Linhai Feng Chao Wu Rongrong Qiu Hongkai Zhang Zhihui Yang Weichun Yang Qi Liao Liyuan Chai School of Metallurgy and Environment Central South UniversityChangsha 410083China National Engineering Research Centre for Control and Treatment ofHeavy Metal Pollution Central South UniversityChangsha 410083China Water Pollution Control Technology Key Lab of Hunan Province Changsha 410083China

Birnessite is ubiquitous in the natural environment where heavy metals are retained and easily transformed.The surface properties and structure of birnessite change with the changes in external environmental conditions,which also affects the fate of heavy metals.Clarifying the effect and mechanism of the birnessite phase transition process on heavy metals is the key to taking effective measures to prevent and control heavy metal pollution.Therefore,the four transformation pathways of birnessite are summarized first in this review.Second,the relationship between transformation pathways and environmental conditions is proposed.These relevant environmental conditions include abiotic(e.g.,co-existing ions,pH,oxygen pressure,temperature,electric field,light,aging,pressure)and biotic factors(e.g.,microorganisms,biomolecules).The phase transformation is achieved by the key intermediate of Mn(Ⅲ)through interlayer-condensation,folding,neutralizationdisproportionation,and dissolution-recrystallization mechanisms.The AOS(average oxidation state)of Mn and interlayer spacing are closely correlated with the phase transformation of birnessite.Last but not least,the mechanisms of heavy metals immobilization in the transformation process of birnessite are summed up.They involve isomorphous substitution,redox,complexation,hydration/dehydration,etc.The transformation of birnessite and its implication on heavy metals will be helpful for understanding and predicting the behavior of heavy metals and the crucial phase of manganese oxides/hydroxides in natural and engineered environments.

关键词： Birnessite transformation Heavy metals Pathways Mechanism

Dynamic coupling of ferrihydrite transformation and associated arsenic desorption/redistribution mediated by sulfate-reducing bacteria

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Journal of Environmental Sciences 2024年第1期135卷 39-50页

作者： Wenjing Zhou Huiyan Zhu Shiwen Hu Bowei Zhang Kun Gao Zhi Dang Chongxuan Liu State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control School of Environmental Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters Ministry of EducationSouth China University of TechnologyGuangzhou 510006China

Sulfate-reducing bacteria play an important role in the geochemistry of iron(oxyhydr)oxide and arsenic(As)in natural environments;however,the associated reaction processes are yet to be fully understood.In this study,batch experiments coupled with geochemical,spectroscopic,microscopic,and thermodynamic analyses were conducted to investigate the dynamic coupling of ferrihydrite transformation and the associated As desorption/redistribution mediated by Desulfovibrio vulgaris(D.vulgaris).The results indicated that D.vulgaris could induce ferrihydrite transformation via S^(2-)-driven and direct reduction processes.In the absence of SO_(4)^(2-),D.vulgaris directly reduced ferrihydrite,and As desorption and re-sorption occurred simultaneously during the partial transformation of ferrihydrite to magnetite.The increase in SO_(4)^(2-)loading promoted the S^(2-)-driven reduction of ferrihydrite and accelerated the subsequent mineralogical transformation.In the low and medium SO_(4)^(2-)treatments,ferrihydrite was completely transformed to a mixture of magnetite and mackinawite,which increased the fraction of As in the residual phase and stabilized As.In the high SO_(4)^(2-)treatment,although the replacement of ferrihydrite by only mackinawite also increased the fraction of As in the residual phase,22.1%of the total As was released into the solution due to the poor adsorption affinity of As to mackinawite and the conversion of As^(5+)to As^(3+).The mechanisms of ferrihydrite reduction,mineralogy transformation,and As mobilization and redistribution mediated by sulfate-reducing bacteria are closely related to the surrounding SO_(4)^(2-)loadings.These results advance our understanding of the biogeochemical behavior of Fe,S,and As,and are helpful for the risk assessment and remediation of As contamination.

关键词： Sulfate-reducing bacteria Arsenic Ferrihydrite transformation Redistribution

Fe(Ⅱ)-mediated transformation of schwertmannite associated with calcium from acid mine drainage treatment

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Journal of Environmental Sciences 2023年第4期126卷 612-620页

作者： Cong Fan Chuling Guo Wei Chen Guining Lu Yu Shen Zhi Dang National Research Base of Intelligent Manufacturing Service Chongqing Technology and Business UniversityChongqing 400067China School of Environment and Energy South China University of TechnologyGuangzhou 510006China The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters Ministry of EducationSouth China University of TechnologyGuangzhou 510006China Chongqing Key Laboratory of Environmental Materials and Remediation Technologies Chongqing University of Arts and SciencesChongqing 402160China

Schwertmannite is an important Fe(Ⅲ)-oxyhydroxysulfate in acid mine drainage (AMD) polluted areas and its stability depends on surrounding environmental factors and previously bound elements.The treatment and neutralization of AMD normally involve the use of lime,which leads to the discharge of abundant Ca in the mining area.Such an environmental disturbance brings up an important and less considered problem of how the reductive transformation of schwertmannite associated with coexisting Ca occurred.Here,the Fe(Ⅱ)-mediated transformation of Ca-adsorbed schwertmannite and subsequent Ca repartitioning behaviors were investigated.Results showed that adsorbed Ca had a weak inhibitory effect on Fe(Ⅱ)-mediated schwertmannite transformation.Release of SO_(4)2-and SEM images both indicated that transformation rates of schwertmannite decreased under the influence of adsorbed Ca.XRD patterns indicated that adsorbed Ca altered schwertmannite transformation pathways and product compositions upon treatment with 0.4 mmol/L Fe(Ⅱ).The end products of Sch notably contained both goethite and lepidocrocite;however,transformation products of SchCa only contained goethite all along.Approximately 33.5%of the surface adsorbed-Ca was released into solution within 6 hr after Fe(Ⅱ) injection.Aqueous Ca behaved in a“first release and then im-mobilization”manner,which indicated dissolution and secondary mineralization drove Ca migration during the Fe(Ⅱ)-mediated transformation of SchCa.Adsorbed Ca blocked the surface sites for subsequent Fe(Ⅱ) adsorption,limited the Fe(Ⅱ)-Fe(Ⅲ) ETAE,and decreased the transformation rates.This work sheds light on the complex geochemical behavior of schwertmannite under the influences of environmental perturbations in AMD environments.

关键词： Acid mine drainage Schwertmannite Calcium Fe(II) transformation

Immobilization and transformation of co-existing arsenic and antimony in highly contaminated sediment by nano zero-valent iron

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Journal of Environmental Sciences 2022年第2期34卷 152-160页

作者： Jianlong Guo Zhipeng Yin Wen Zhong Chuanyong Jing State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China School of Environmental Science and Engineering Shandong UniversityQingdao 266237China

Arsenic(As)and antimony(Sb)are usually coexistent in mine wastes and pose a great threat to human health.The As immobilization by nano zero-valent iron(n ZVI)is promising,however,the stabilization for co-occurring As and Sb is not known.Herein,the immobilization and transformation of As and Sb in n ZVI-treated sediments were evaluated using complementary leaching experiments and characterization techniques.Raw sediment samples from a gold-antimony deposit revealed the co-existence of ultrahigh As and Sb at 50.3 and 14.9 g/kg,respectively.Leaching results show that As was more efficiently stabilized by n ZVI than Sb,which was primarily due to the soluble fraction that was readily absorbed by n ZVI of As was higher.As the n ZVI treatment proceeds,the oxidation and reduction of As and Sb occur simultaneously as evidenced by XPS analysis.The primary oxidant,hydroxyl radicals,was detected by EPR studies,proving the occurrence of n ZVI induced Fenton reaction.This study sheds light on differences in the interaction and immobilization of n ZVI with Sb and As in co-contaminated sediments.

关键词： Arsenic Antimony Nano zero-valent iron Immobilization transformation Leaching

transformation devices with optical nihility media and reduced realizations

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Frontiers of physics 2019年第4期14卷 117-124页

作者： Lin Xu Qian-Nan Wu Yang-Yang Zhou Huan-Yang Chen Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education & Institutes of Physical Science and Information Technology Anhui University Hefei 230601 China School of Science North University of China Taiyuan 030051 China Institute of Electromagnetics and Acoustics and Department of Electronic Science Xiamen University Xiamen 361005 China

Starting from optical nihility media (ONM),we design several intriguing devices with transformation optics method in two dimensions,such as a wave splitter,a concave lens,a field rotator,a concentrator,and an invisibility cloak.Though the extreme anisotropic property of ONM hinders the fabrication of these devices.We demonstrate that those devices could be effectively realized by simplified materials with Fabry-Pérot resonances (FPs) at discrete frequencies.Moreover,we propose a reduced version of simplified materials with FPs to construct a concentrator and a rotator,which is feasible in experimental fabrications.The simulations of total scattering cross-sections confirm their functionalities.

关键词： transformation optics optical nihility media Fabry-Perot resonances

From De-collectivization to Re-collectivization: New transformation Trend in Agriculture Production in Taicang City of the Eastern China from the Perspective of ‘Governmentality’

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Chinese Geographical Science 2023年第3期33卷 531-548页

作者： CHEN Cheng GAO Jinlong CAO Hui CHEN Jianglong CHEN Feiyu Key Laboratory of Watershed Geographic Sciences Nanjing Institute of Geography and LimnologyNanjing 210008China Jiangsu Collaborative Innovation Center of Regional Modern Agriculture&Environmental Protection Huaiyin Normal UniversityHuaian 223001China Nanjing College University of Chinese Academy of ScienceNanjing 211135China

The continuous development of agricultural technologies and produces trade and updated state reforms strongly shape the dominant organizing styles of local agriculture production.Since the end of the 1970s,rural China has witnessed a drastic agriculture transformation featured by de-collectivization,and recently in Taicang,a developed city in the eastern China,a kind of new cooperative farms have replaced the smallholders by pooling households’contracted farmland,signaling a new shift tendency towards agriculture recollectivization that is distinctive compared to other countries.Given the state governance’s leadership in promoting this latest transformation,drawing on the theoretical concept of‘governmentality’that is powerful in understanding how to govern the society to meet certain objectives,this paper examines the accurate processes of agriculture re-collectivization in Taicang City based on the methods of semi-structured interview and participant observation.Our research shows that the China’s tax-sharing and relevant reforms in the 1990s framed a new governance structure in line with the new mode of‘governmentality’closely linked to‘advanced liberalism’,creating the responsibility shift from central to local governments and a set of evaluation technologies,and guiding various actors to engage in the agriculture re-collectivization practice in Taicang.Importantly,the considerable subsidies and the impressive extension services in terms of farming personnel training and agricultural techniques diffusion underpin the normal running of cooperative farms and contribute to the local implementation of national strategy of agriculture modernization.We argue that the combination of distinctive institutional arrangement of rural land owned by village collectives in China and the burgeoning local economy allows the developed areas to re-collectivizing the agriculture production for ensuring grain self-sufficiency rather than capturing more share in global agriculture products trade,and that the cooperative farms in o

关键词： Eastern transformation collective

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

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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 phosphorus.However,the composition and variation of dissolved organic phosphorus(DOP)in WWTPs were unclear because of its complex nature,hindering its efficient detection.In this study,the DOP species and their transformation during the treatment process in WWTP were comprehensively analyzed.First,two enrichment methods were assessed for their effectiveness at facilitating wastewater analysis:lyophilization and aluminum salt precipitation.Aluminum 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 elucidated.Among the treatment steps,biological treatment combined tertiary treatment achieved better DOP removal efficiencies.Therein,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 chamber.Di-P has higher bioavailability and is more easily converted and utilized by microorganisms than Mono-P.However,Phos-P,with low bioavailability,was hardly utilized by microorganisms,which showed only 18.4%removal efficiency in biological treatment.In 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 TP.In addition,Phos-P could not be effectively removed through the biological treatment and was only partially reduced via the adsorption process by large particles,zoogloea or multinuclear

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