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Efficient and selective recovery of gd(Ⅲ)via polyethyleneimine modification of lanthanum-based metal-organic frameworks

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Journal of Rare Earths 2024年第1期42卷 210-219,I0007页

作者： Wenhao li lijinhong Huang Bin Xiao Xiaoguang Duan Haike li Lang li Wanfu Huang ganzhou Key Laboratory of Basin Pollution Simulation and Control Jiangxi University of Science and TechnologyGanzhou341000China Innovation Center for Water Quality Security Technology at ganjiang River Basin Jiangxi University of Science and TechnologyGanzhou341000China Faculty of Science and Engineering WA School of Mines:MineralsEnergy and Chemical EngineeringCurtin UniversityWAAustralia School of Architecture and Design Jiangxi University of Science and TechnologyGanzhou341000China School of Resources and Architectural Engineering Gannan University of Science and TechnologyGanzhou341000China School of Chemical Engineering and Advanced Materials The University of AdelaideAdelaideSA5005Australia School of Resource and Environmental Engineering Jiangxi University of Science and TechnologyGanzhou341000China

With the development of the economy and the increasing demand for environmental protection,the efficient and selective recovery of gd(Ⅲ)from actual wastewater is of critical *** this work,lanthanum-based metal-organic framework(LaBDC)materials were prepared by a hydrothermal method,and then polyethyleneimine(PEI)and LaBDC were combined by an impregnation method to form a novel LaBDC@xPEI *** prepared materials were characterized using Fourier transfo rm infrared spectroscopy(FTIR),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDX),B runauer-Emmett-Teller(BET),thermogravimetric analysis(TgA)and X-ray photoelectron spectroscopy(XPS).Experiments show that LaBDC@50%PEI has the highest adsorption capacity(181.77 mg/g)among lanthanum-based MOFs with different PEI loadings at pH=5.5,which is about 5.1 times that of bare *** adsorption isotherm analysis shows that LaBDC@50%PEI follows the Langmuir *** addition,the adsorption kinetics of LaBDC@50%PEI follows a pseudo-second-order kinetic model,indicating that the adsorption process is chemical *** is worth noting that LaBDC@50%PEI maintains good adsorption performance and stability after three recycling tests,and exhibits excellent selectivity in cation interference ***,the LaBDC@50%PEI composites possess good stability and hold great promises in rapid recovery of gd(Ⅲ)from practical aqueous environments.

关键词： Wet-impregnation method Polyethylene imine Metaleorganic frameworks Lanthanum Recovery of gd(Ⅲ) Rare earths

Effects of ignition voltage and electrode structure on electric ignition and combustion characteristics of Ammonium Dinitramide(ADN)-based liquid propellants in electric ignition mode in inert gas environment

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Chinese Journal of Aeronautics 2024年第4期37卷 229-242页

作者： Lei li guoxiu li Hongmeng li Zhaopu YAO Tao ZHANg Jinze WU Shuo ZHANg School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Beijing Institute of Control Engineering Beijing 100190China

Hydrazine is toxic and carcinogenic, which greatly increases the difficulty of application and no longer meets the needs of green aerospace. As a green propellant, the Ammonium Dinitramide(ADN)-based liquid propellant has the advantages of higher specific impulse, being non-toxic,pollution-free, and easy storage. However, an ADN-based space engine in orbit has exposed the problems of high-temperature deactivation of catalysts and cold-start failure. An active ignition technology—electric ignition technology was explored in this paper to break through the technical bottleneck of catalyst deactivation and the inability to a cold start. An experimental system of a constant-volume combustor for the ADN-based liquid propellant based on the electric ignition method was established. The electric ignition and combustion characteristics of the ADN-based liquid propellant in a volume combustor with an electric ignition method were studied. The influencing mechanisms of the ignition voltage and the electrode structure on the electric ignition characteristics of the ADN-based liquid propellant were investigated. An elevation of the ignition voltage could facilitate the ignition process of the ADN-based liquid propellant, curtail electric energy input and heating effect, while exerting an adverse impact on the combustion process of the *** increase in the ignition voltage enhanced the ignition process of the propellant while simultaneously suppressing its combustion process when utilizing mesh electrodes. Compared to the strip electrodes, the mesh electrodes increased the contact area between the electrodes and the propellant,increased the electric energy input power in the electric ignition process, and reduced the ignition delay time. The mesh electrodes could promote the combustion process of the propellant to a certain extent.

关键词： ADN-based liquid propellant Resistive ignition Electrical ignition characteristic Combustion Inert gas

Boosting Hydrogen Storage Performance of MgH_(2) by Oxygen Vacancy-Rich H-V_(2)O_(5) Nanosheet as an Excited H-Pump

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Nano-Micro Letters 2024年第8期16卷 398-416页

作者： li Ren Yinghui li Zi li Xi lin Chong Lu Wenjiang Ding Jianxin Zou National Engineering Research Center of light Alloys Net Forming&State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Shanghai Engineering Research Center of Mg Materials and Applications&School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Center of Hydrogen Science Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Instrumental Analysis Center of SJTU Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China

MgH_(2) is a promising high-capacity solid-state hydrogen storage material,while its application is greatly hindered by the high desorption temperature and sluggish ***,intertwined 2D oxygen vacancy-rich V_(2)O_(5) nanosheets(H-V_(2)O_(5))are specifically designed and used as catalysts to improve the hydrogen storage properties of MgH_(2).The as-prepared MgH_(2)-H-V_(2)O_(5) composites exhibit low desorption temperatures(Tonset=185℃)with a hydrogen capacity of 6.54 wt%,fast kinetics(Ea=84.55±1.37 kJ mol^(-1) H_(2) for desorption),and long cycling ***,hydrogen absorption can be achieved at a temperature as low as 30℃ with a capacity of 2.38 wt%within 60 ***,the composites maintain a capacity retention rate of~99%after 100 cycles at 275℃.Experimental studies and theoretical calculations demonstrate that the in-situ formed VH_(2)/V catalysts,unique 2D structure of H-V_(2)O_(5) nanosheets,and abundant oxygen vacancies positively contribute to the improved hydrogen sorption ***,the existence of oxygen vacancies plays a double role,which could not only directly accelerate the hydrogen ab/de-sorption rate of MgH_(2),but also indirectly affect the activity of the catalytic phase VH_(2)/V,thereby further boosting the hydrogen storage performance of MgH_(2).This work highlights an oxygen vacancy excited“hydrogen pump”effect of VH_(2)/V on the hydrogen sorption of Mg/MgH_(2).The strategy developed here may pave a new way toward the development of oxygen vacancy-rich transition metal oxides catalyzed hydride systems.

关键词： Hydrogen storage MgH_(2) V_(2)O_(5)nanosheets Oxygen vacancies VH_(2)

Solvent extraction of scandium from leaching solution of red mud roasted with ammonium sulfate using D2EHPA/TBP

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Journal of Rare Earths 2024年第10期42卷 1943-1949页

作者： Fucheng li Xinsheng li Lei Shi Xiang li Duoqiang liang Yuezhou Wei Toyohisa Fujita School of Resources Environment and MaterialsGuangxi University State Key Laboratory of Featured Metal Materials and life-cycle Safety for Composite Structures Guangxi University School of Nuclear Science and Technology University of South China

Red mud is an important secondary resource for scandium *** red mud leaching solution containing scandium in this study was derived from environmentally friendly ammonium sulfate roasting and water leaching process.A synergistic extraction with a mixture of di（2-ethylhexyl） phosphate acid（D2EHPA） and tributyl phosphate（TBP） for recovery of scandium from red mud leaching solution is *** effects of D2EHPA concentration,H2SO4concentration,rare earth elements,dosage of TBP,phase ratio（A/O）,contact time and H2O2concentration on scandium extraction were *** results show that more than 99% scandium is extracted under the optimal conditions while Fe,Al,Ti,Ca and rare earth elements（Ce,Y,La,Nd,Er,etc.） are hardly *** stripping efficiency of Sc reaches above 92.37% under the optimal stripping conditions of 5 mol/L NaOH with an A/O of 1 at 90℃ for 30 *** proposed technology could provide an effective method for extraction of scandium from red mud leaching solution.

关键词： D2EHPA/TBP Rare earths Red mud leaching solution Scandium Solvent extraction

Stability assessment of tree ring growth of Pinus armandii Franch in response to climate change based on slope directions at the Lubanling in the Funiu Mountains,China

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Journal of Forestry Research 2024年第3期35卷 197-208页

作者： Jinkuan li Jianfeng Peng Xiaoxu Wei Meng Peng Xuan li Yameng liu Jiaxin li College of geography and Environmental Science Henan UniversityKaifeng 475004People’s Republic of China Key Laboratory of Earth System Observation and Simulation of Henan Province Kaifeng 475004People’s Republic of China

global warming will affect growth strategies and how trees will *** compare the response of tree radial growth to climate warming in different slope directions,samples of Pinus armandii Franch were collected and treering chronologies developed on northern and western slopes from the Lubanling in the Funiu *** analyses showed that two chronologies were mainly limited by temperatures in the previous June–August and the combination of temperatures and moisture in the current May–*** difference of the climate response to slopes was small but not *** growth of the LBL01 site on the northern slope was affected by the combined maximum and minimum temperatures,while that of the LBL02 site was affected by maximum *** regards to moisture,radial growth of the trees on the north slope was influenced by the relative humidity in the current May–July,while on the western slope,it was affected by the relative humidity in the previous June–August,the current May–July and the precipitation in the current May–*** the change in climate,the effects of the main limiting factors on growth on different slopes were visible to a certain extent,but the differences in response of trees on different slopes gradually decreased,which might be caused by factors such as different slope directions and the change in diurnal temperature *** results may provide information for forest protection and ecological construction in this region,and a scientific reference for future climate reconstruction.

关键词： Tree ring width Lubanling Pinus armandii Franch Slope direction Climate response

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Effect of nitrile butadiene rubber hardness on the sealing characteristics of hydraulic O-ring rod seals

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第1期25卷 63-78页

作者： Xiaoxuan li Bingqing WANg Xudong PENg Yuntang li Xiaolu li Yuan CHEN Jie JIN College of Quality and Safety Engineering China Jiliang UniversityHangzhou310018China College of Mechanical and Electrical Engineering China Jiliang UniversityHangzhou310018China College of Mechanical Engineering Zhejiang University of TechnologyHangzhou310023China

The nitrile butadiene rubber(NBR)hardness effect on the sealing characteristics of hydraulic O-ring rod seals is analyzed based on a mixed lubrication elastohydrodynamic *** studies are conducted to reveal the mechanism of the influence of rubber hardness on the static and dynamic behavior of *** optimized selections of rubber hardness are then investigated under different *** show that the low hardness seal is prone to stress concentration due to the extrusion effect under high pressure conditions;it is also more prone to leaking.A high hardness seal can better prevent leakage by reducing film thickness but it will cause large frictional power loss and increase the probability of wear *** choice of low hardness is recommended to reduce friction with the premise that leakage requirements are met.

关键词： Nitrile butadiene rubber(NBR)hardness Sealing characteristics Optimized selection O-ring seal

DC Traction Power Supply System Based on Modular Multilevel Converter Suitable for Energy Feeding and De-icing

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 649-659页

作者： lingxi Hou Shuqing Zhang Yingdong Wei Xiaoqian li Qirong Jiang Mingrui li Weirui li Department of Electrical Engineering Tsinghua UniversityBeijing 100084China

A novel DC traction power supply system suitable for energy feeding and de-icing is proposed in this paper for an urban rail transit catenary on the basis of the full bridge submodule (FBSM) modular multilevel converter (MMC). The FBSM-MMC is a novel type of voltage source converter (VSC) and can directly control the output DC voltage and conduct bipolar currents, thus flexibly controlling the power flow of the urban rail transit catenary. The proposed topology can overcome the inherent disadvantages of the output voltage drop in the diode rectifier units, increase the power supply distance and reduce the number of traction substations. The flexible DC technology can coordinate multiple FBSM-MMCs in a wide area and jointly complete the bidirectional control of catenary power flow during the operation of the electric locomotive, so as to realize the local consumption and optimal utilization of the recovered braking energy of the train. In addition, the FBSM-MMCs can also adjust the output current when the locomotive is out of service to prevent the catenary from icing in winter. The working modes of the proposed topology are illustrated in detail and the control strategy is specially designed for normal locomotive operations and catenary de-icing. Simulation cases conducted by PSCAD/EMTDC validate the proposed topology and its control strategy.

关键词： DC traction power supply system de-icing for catenary energy feeding modular multilevel converter based on full-bridge submodules(FBSM-MMC) urban rail transit

Transcriptomics and physiological analyses reveal that sulfur alleviates mercury toxicity in rice(Oryza sativa L.)

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Journal of Environmental Sciences 2024年第1期135卷 10-25页

作者： Yingmei Huang Jicai Yi Xiaomin li Fangbai li National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and ManagementInstitute of Eco-Environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China guangzhou Institute of geochemistry Chinese Academy of SciencesGuangzhou 510640China University of Chinese Academy of Sciences Beijing 100049China College of life Sciences South China Agricultural UniversityGuangzhou 510642China SCNU Environmental Research Institute Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety&MOE Key Laboratory of Theoretical Chemistry of EnvironmentSouth China Normal UniversityGuangzhou 510006China

Mercury(Hg)is one of the most dangerous contaminants and has sparked global concern since it poses a health risk to humans when consumed through ***(S)is a crucial component for plant growth,and S may reduce Hg accumulation in rice ***,the detailed effects of S and the mechanisms underlying S-mediated responses in Hg-stressed rice plants remain ***,to investigate the effects of S addition on rice growth,Hg accumulation,physiological indexes,and gene expression profiles,rice seedlings were hydroponically treated with Hg(20μmol/L Hg Cl_(2))and Hg plus elemental sulfur(100 mg/L).S application significantly reduced Hg accumulation in Hg-stressed rice roots and alleviated the inhibitory effects of Hg on rice growth.S addition significantly reduced Hg-induced reactive oxygen species generation,membrane lipid peroxidation levels,and activities of antioxidant enzymes while increasing glutathione content in *** analysis of roots identified 3,411,2,730,and 581 differentially expressed genes in the control(CK)***,CK ***+S,and Hg ***+S datasets,*** pathway of S-mediated biological metabolism fell into six groups:biosynthesis and metabolism,expression regulation,transport,stimulus response,oxidation reduction,and cell wall *** majority of biological process-related genes were upregulated under Hg stress compared with CK treatment,but downregulated in the Hg+S *** results provide transcriptomic and physiological evidence that S may be critical for plant Hg stress resistance and will help to develop strategies for reduction or phytoremediation of Hg contamination.

关键词： Sulfur Mercury Transcriptomics Detoxification

A dynamic soil freezing characteristic curve model for frozen soil

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Journal of Rock Mechanics and geotechnical Engineering 2024年第8期16卷 3339-3352页

作者： Xiaokang li Xu li Jiankun liu Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing100044China School of Civil Engineering Sun Yat-sen UniversityZhuhai519082China

The soil freezing characteristic curve(SFCC)plays a fundamental role in comprehending thermohydraulic behavior and numerical simulation of frozen *** study proposes a dynamic model to uniformly express SFCCs amidst varying total water contents throughout the freezing-thawing ***,a general model is proposed,wherein the unfrozen water content at arbitrary temperature is determined as the lesser of the current total water content and the reference value derived from saturated *** dynamic performance of this model is verified through test ***,in accordance with electric double layer(EDL)theory,the theoretical residual and minimum temperatures in SFCC are calculated to be-14.5℃to-20℃for clay particles and-260℃,*** ensure that the SFCC curve ends at minimum temperature,a correction function is introduced into the general ***,a simplified dynamic model is proposed and investigated,necessitating only three parameters inherited from the general ***,both general and simplified models are evaluated based on a test database and proven to fit the test data exactly across the entire temperature *** recommended parameter values for various types of soils are ***,this study provides not only a theoretical basis for most empirical equations but also proposes a new and more general equation to describe the SFCC.

关键词： Frozen soils Unsaturated soils Soil freezing characteristic curve(SFCC) Mathematic models