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High capacity adsorption of iodine gas by Ag⁰@c/SiO2 derived from rice husk: synergistic effect between c/SiO2 supports and Ag⁰ sites

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JOURNAL OF RADIOANALYTIcAL AND NUcLEAR cHEMISTRY 2023年第8期332卷 3059-3068页

作者： Xiong, Yingwei Ai, Yanru Wang, Hongxun Wang, Enchao Dan, Hui Ding, Yi Mianyang TeachersCollege Chuanxibei RHS Construct Mianyang Teachers Coll Si Engn Res Ctr Mianyang 621000 Peoples R China Technol Res Inst Ecol Energy Saving Environm Protect & Low Carbon Mianya Mianyang 621010 Peoples R China Southwest Univ Sci & Technol Sch Natl Def Sci & Technol Mianyang 621010 Peoples R China

A series of Ag-0@c/SiO2 adsorbents were prepared using rice husk-based c/SiO2 as supports and applied to capture iodine gas. The results demonstrated that 50%Ag-0@c/SiO2 reached a record high iodine adsorption capacity (788 +/- 25 mg/g) due to the synergistic effect between c/SiO2 supports and Ag-0 sites. The adsorption data of Ag-0@c/SiO2 can be better fitted with the pseudo first order and Langmuir models. The iodine adsorption process included the physical and chemical adsorption. The adsorption mechanism was that Ag-0 reacted with I-2 to form AgI. Owing to the excellent adsorption capacity, Ag-0@c/SiO2 derived from rice husk could be promising iodine gas adsorbents.

关键词： Iodine gas Silver Rice husk c SiO2 Adsorption

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Three-dimensional micro-pipelines high thermal conductive c/Sic composites

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cERAMIcS INTERNATIONAL 2021年第24期47卷 34333-34340页

作者： Zhang, Yunhai Liu, Yongsheng cao, Liyang Fang, Hui Liu, Bin cao, Yejie Wang, Jing chen, Jian Pan, Yu Northwestern Polytech Univ Sci & Technol Thermostruct Composite Mat Lab Xian 710072 Shaanxi Peoples R China Northwestern Polytech Univ Sch Aeronaut Xian 710072 Shaanxi Peoples R China Acad Mil Sci PLA China Natl Innovat Inst Def Technol Beijing 100071 Peoples R China Natl Univ Def Technol Coll Aerosp Sci & Engn Sci & Technol Scramjet Lab Changsha 410073 Hunan Peoples R China

carbon/silicon carbide (c/Sic) composites are usually regarded as thermal protective system materials and widely applied in hypersonic vehicles or ramjet. However, poor thermal conductivity of c/Sic composites, leading to severe heat concentration and thermal stress during the high-speed operation of hypersonic vehicle, limits their broad-range of practical applications. Modification with high thermal conductive fillers is an optional method;however, controllable dispersion and orientation of the fillers to construct continuous and ordered heat conductive channel has been proven to be a challenging task. Herein, based on high thermal conductivity fibers, a three-dimensional micro-pipeline preform was developed for the preparation of structure-function integrated c/Sic composites. The technical feasibility of the method, the characteristics of microstructures, and the thermal conductivity and bending strength of the as-obtained composites were systematically studied. Results revealed that the thermal conductivities of as-obtained composites reached 150.2 and 46.7 W m-1 K-1 for in-plane and out-of-plane direction, respectively. The bending strength obtained herein is 264.4 MPa, which is lower than that of polyacrylonitrile c/Sic composites. However, the fine control over the component and microstructure or densification could provide a higher value in the future research. In sum, the proposed method provides a convenient and feasible approach to prepare high thermal conductive c/Sic composites.

关键词： c Sic composites Micro-pipelines Thermal conductivity Bending strength Heat conductive channels

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Simultaneous nitrogen and carbon removal in a packed A/O reactor: effect of c/N ratio on microbial community structure

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BIOPROcESS AND BIOSYSTEMS ENGINEERING 2020年第7期43卷 1241-1252页

作者： Ding, Shuai He, Jian Luo, Xingzhang Zheng, Zheng Fudan Univ Dept Environm Sci & Engn Room 2026Environm Bldg2005 Songhu Rd Shanghai 200433 Peoples R China

In this research, a novel packed anoxic/oxic moving bed biofilm reactor (MBBR) was established to achieve high-organic matter removal rates, despite the carbon/nitrogen (c/N) ratio of 2.7-5.1 in the influent. Simultaneous nitrification-denitrification (SND) was investigated under a long sludge retention time of 104 days. The system exhibited excellent performance in pollutant removal, with chemical oxygen demand and total nitrogen (TN) enhanced to 93.6-97.4% and 34.4-60%, respectively. Under low c/N conditions, the nitrogen removal process of A/O MBBR system was mainly achieved by anaerobic denitrification. The increase of c/N ratio enhanced SND rate of the aerobic section, where dissolved oxygen was maintained at the range of 4-6 mg/L, and resulted in higher TN removal efficiency. The microbial composition and structures were analyzed utilizing the MiSeq Illumina sequencing technique. High-throughput pyrosequencing results indicated that the dominant microorganisms were Proteobacteria and Bacteroidetes at the phylum level, which contributes to the removal of organics matters. In the aerobic section, abundances of Nitrospirae (1.12-29.33%), Burkholderiales (2.15-21.38%), and Sphingobacteriales (2.92-11.67%) rose with increasing c/N ratio in the influent, this proved that SND did occur in the aerobic zone. As the c/N ratio of influent increased, the SND phenomenon in the aerobic zone of the system is the main mechanism for greatly improving the removal rate of TN in the aerobic section. The c/N ratio in the aerobic zone is not required to be high to exhibit good TN removal performance. When c/NH4+ and c/TN in the aerobic zone were higher than 2.29 and 1.77, respectively, TN removal efficiency was higher than 60%, which means that carbon sources added to the reactor could be saved. This study would be vital for a better understanding of microbial structures within a packed A/O MBBR and the development of cost-efficient strategies for the treatment of low c/N wastewate

关键词： Packed A O reactor Moving bed biofilm reactor c N ratio Simultaneous nitrification-denitrification (SND) Microbial community structure

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Soil c and N dynamics and maize (Zea may L.) yield as affected by croping systems and residue management in North-western Pakistan

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SOIL & TILLAGE RESEARcH 2007年第2期94卷 520-529页

作者： Shafi, Mohammad Bakht, Jehan Jan, Mohammad Tariq Shah, Zahir Agr Univ NWFP Dept Agron Peshawar Pakistan Agr Univ NWFP Dept Soil Sci & Environm Sci Peshawar Pakistan

This paper presents the results of irrigated rotation experiment, conducted in the North West Frontier Province (NWFP), Pakistan, during 1999-2002 to evaluate effects of residues retention, fertilizer N and legumes in crop rotation on yield of maize (Zea mays L.) and soil organic fertility. chickpea (cicer arietinum Q and wheat (Triticum aestivum Q were grown in the winters and mungbean (Vigna radiata) and maize in the summers. Immediately after grain harvest, above-ground residues of all crops were either completely removed (-residue), or spread across the plots and incorporated by chisel plough by disc harrow and rotavator (+residue). Fertlizer N rates were nil or 120 kg ha(-1) for wheat and nil or 160 kg ha(-1) for maize. Our results indicated that post-harvest incorporation of crop residues significantly (p < 0.05) increased the grain and stover yields of maize during both 2000 and 2001. On average, grain yield was increased by 23.7% and stover yield by 26.7% due to residue incorporation. Residue retention also enhanced N uptake by 28.3% in grain and 45.1% in stover of maize. The soil N fertility was improved by 29.2% due to residue retention. The maize grain and stover yields also responded significantly to the previous legume (chickpea) compared with the previous cereal (wheat) treatment. The legume treatment boosted grain yield of maize by 112% and stover yield by 133% with 64.4% increase in soil N fertility. Similarly, fertilizer N applied to previous wheat showed considerable carry over effect on grain (8.9%) and stover (40.7%) yields of the following maize. Application of fertilizer N to current maize substantially increased grain yield of maize by 110%, stover yield by 167% and soil N fertility by 9.8% over the nil N fertilizer treatment. We concluded from these experiments that returning of crop residues, application of fertilizer N and involvement of legumes in crop rotation greatly improves the N economy of the cropping systems and enhances crop produc

关键词： maize N c crop residues cropping systems

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One-step combustion synthesis of c/MgO composite powders with MgO nanofibers

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cERAMIcS INTERNATIONAL 2021年第10期47卷 13704-13714页

作者： Li, Kaidi Xiao, Guoqing Ding, Donghai chong, Xiaochuan Luo, Jiyuan chen, Xing Bai, Bing Ren, Yun Xian Univ Architecture & Technol Coll Mat Sci & Engn Xian 710055 Peoples R China

c/MgO composite powders were prepared by combustion synthesis using magnesium oxalate and magnesium powders as raw materials. The phase composition and microstructure of the composite powders were investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy/energy dispersive spectroscopy (FESEM/EDS), high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. The synthetic mechanism was explored through TG-FTIR and combustion front quenching techniques. It was found that the c/MgO composite powders contained a large quantity of MgO nanofibers. When the molar ratio of magnesium oxalate and magnesium was 1:4, the carbon content of the product reached a maximum of 9.45 wt %. In the composite powders, cubic MgO particles were encapsulated by a thin carbon layer, and there was a tiny gap between MgO and the carbon layer;a large number of MgO nanofibers with aspect ratios of 80?100 were found. The cubic MgO particles of the products are the direct decomposition of Mgc2O4, and the MgO nanofibers are the reaction product of gaseous Mg and cO2/cO at high temperature. Meanwhile, the carbon deposited on the MgO particles can inhibit the grain growth of MgO particles and result in the refinement of MgO particles. The uniform dispersion of carbon and the weak c/MgO interface combine, making the composite powders a potential additive for low-carbon MgO?c refractories with excellent thermal shock resistance.

关键词： combustion synthesis c MgO composite Powders MgO nanofibers

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comparison of ESI-MS/MS and APcI-MS methods for the quantification of folic acid analogs in c. elegans

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JOURNAL OF MASS SPEcTROMETRY 2019年第4期54卷 316-327页

作者： Annibal, Andrea Tam, Hannah Latza, christian Antebi, Adam Max Planck Inst Biol Ageing Cologne Germany Univ Cologne Cologne Excellence Cluster Cellular Stress Respon Cologne Germany

Folic acid (FA) plays a vital role in central metabolism, including the one carbon cycle, nucleotide, and amino acid biosynthesis. The development of sensitive, accurate analytical methods to measure FA intermediates in tissues is critical to understand their biological roles in diverse physiological and pathological contexts. Here, we developed a highly sensitive method for the simultaneous quantification of FA intermediates in the nematode caenorhabditis elegans as a model to dissect metabolic networks. The method was further validated by analyzing the worm folate pool upon RNAi knockdown of the dihydrofolate reductase gene dhfr-1. comparative mass spectrometry behavior of the FA analogs using two different ion sources, electrospray ionization (ESI) and atmospheric pressure chemical ionization (APcI), revealed ESI-MS/MS to be more sensitive, but APcI-MS provided more detailed structure inferences, which can elucidate chemical investigation and synthesis of FA analogs. Finally, we report on the use of in vitro oxidation coupled with high-resolution mass spectrometry as a tool to discover new endogenous FA derivatives in the nematode.

关键词： APcI c elegans dhfr-1 ESI folic acid

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Ablation behavior of mullite modified c/c-Sic-Hfc composites under oxyacetylene torch for single and cyclic ablations with two heat fluxes

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JOURNAL OF THE EUROPEAN cERAMIc SOcIETY 2023年第14期43卷 5851-5862页

作者： Jiao, Xiaoyang He, Qinchuan Tan, Qing Yin, Xuemin Chengdu Univ Technol Coll Mat & Chem & Chem Engn Chengdu 610059 Peoples R China Northwestern Polytech Univ Sch Mat Sci & Engn Xian Peoples R China

To investigate the ablation mechanism of the mullite modified c/c-Sic-Hfc composites prepared by precursor infiltration pyrolysis, a 60 s single ablation and 30 s x 3 cyclic ablations were carried out at heat fluxes of 2.38 and 4.18 MW/m2, respectively. Results showed that the ablation temperatures played a vital role in the ablation process. Under the lower heat flux condition, the single ablation behavior was mainly influenced by the escape of gaseous oxidation products and slight airflow erosion, while cyclic ablation was influenced primarily by the stresses induced by crystallization transformation during the heating-cooling process. Under the higher heat flux condition, HfSiO4 was gradually generated at the interface between HfO2 and SiO2, which stabilized the crystallization of HfO2. The ablation behavior under higher heat flux was mainly influenced by thermal-induced stresses and mechanical forces of high-velocity airflow.

关键词： c c-Sic-Hfc composites Mullite Precursor infiltration and pyrolysis Microstructure Ablation

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Facile synthesis and electrochemical properties of high tap density LiFePO4/c

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IONIcS 2019年第10期25卷 4589-4596页

作者： Wang, Xiaoyan Wen, Lizhi Zheng, Yi Liu, Hao Liang, Guangchuan Hebei Univ Technol Inst Power Source & Ecomat Sci Tianjin 300130 Peoples R China North China Univ Sci & Technol Qinggong Coll Tangshan 063000 Peoples R China Tianjin Sino German Univ Appl Sci Automobile & Rail Transportat Sch Tianjin 300350 Peoples R China Hebei Univ Technol Key Lab Special Funct Mat Ecol Environm & Informa Minist Educ Tianjin 300130 Peoples R China Hebei Univ Technol Key Lab New Type Funct Mat Hebei Prov Tianjin 300130 Peoples R China

A facile way of synthesizing LiFePO4/c with high tap density was introduced. LiFePO4/c composites were synthesized by a combination of wet ball milling, spray drying, and carbothermal reduction technology using inexpensive FePO4. The effect of sphericity of secondary microsphere on electrochemical properties and tap density of LiFePO4/c composite was systematically investigated. The sphericity of the secondary microsphere is controlled by particle size of primary particle with varying the ball grinding time. The composites were characterized in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), and tap density testing. The particle size of primary particle can effectively influence the sphericity of the secondary microsphere, and consequently change the electrochemical properties and tap density of LiFePO4/c. The optimum LiFePO4/c with high tap density of 1.68 g cm(-3) contains 2.1 wt% carbon and shows an excellent rate capability and cycle performance, with the initial discharge capacities of 164.0, 159.6, 154.9, 148.3, and 138.3 mAh g(-1) at 0.2 c, 0.5 c, 1 c, 2 c, and 5 c. The good electrochemical properties are attributed to the smaller particle, uniform primary particle size distribution, and the uniform carbon coating. The high tap density of LiFePO4/c composite is attributed to the better sphericity of secondary microsphere. With the primary particle size decreasing, the secondary microsphere sphericity is better.

关键词： LiFePO4 c Sphericity High tap density Electrochemical properties Particle size

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Thermal performance and ablation characteristics of c/c-Sic for thermal protection of hypersonic vehicle

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JOURNAL OF THE EUROPEAN cERAMIc SOcIETY 2021年第11期41卷 5427-5436页

作者： Shi, Yi-ang Zha, Bai-lin Su, Qing-dong Wang, Jin-jin Li, Si-ye Rocket Force Univ Engn Xian 710025 Peoples R China Project Management Ctr Beijing 100085 Peoples R China

A small-scale plasma ablation facility was employed to test the c/c-Sic composite material for investigating the thermal performance and ablation characteristics under two heat flux conditions, 3593.54 kW.m- 2 and 5644.86 kW.m-2. The morphology of post-test specimens was analyzed with the ablation rates calculated. The average mass ablation rates of two group specimens were 0.01735 and 0.10620 g.s-1 respectively with average linear ablation rate of 0.00680 and 0.09407 mm.s-s1. Specimen surface could be divided into three regions with typical layered structure characteristics. For the stagnation point ablation test, the structural deformation in the ablation surface area featured in vertical layering and lateral regionality, forming an ablation pit near the stagnation point. In the center region, sublimation occured primarily, accompanied by a serious jet scouring of the molten liquid phase, as well as a small amount of oxidation reaction;Jet erosion with thermal sublimation was the main factor for the mass loss in the transitional region;Thermochemical reactions were mainly carried out in the marginal region. The SiO2 generated from the thermochemical reaction of the material filled the interspace well and prevented the thermochemical reaction from penetrating deeper through the crack. The protective layer in the molten state with high viscosity reduced the damage of the high-speed jet impact material.

关键词： c c-Sic composite material Ablation rates Ablation characteristics Thermal protection performance

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Porous coP/c derived from metal-organic framework as high-performance anode materials for superior lithium storage

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IONIcS 2023年第5期29卷 2087-2092页

作者： Huang, Binqi Liu, Jiaming Hu, Xingrong Lin, Xing Zhang, Lu Li, Wei Jiangxi Univ Sci & Technol Fac Mat Met & Chem Ganzhou 341000 Peoples R China Yunnan Univ Sch Chem Sci & Technol Kunming 650091 Peoples R China

coP has attracted increasing attention due to its high theoretical capacity for lithium storage. However, coP suffers from a large volume expansion during cycling, which leads to electrode pulverization and poor cycle stability. In addition, the conductivity of coP is poor, resulting in undesirable rate performance. To solve this problem, the coP/c composite was prepared based on the in-situ phosphating heat treatment technology of co-BTc MOF. The as prepared coP/c exhibits a good lithium storage specific capacity and a cycle stability, which is attributed by the synergistic effect of the porous nanostructure and carbon frame. The porous nanostructure of the coP/c allows the electrolyte to easily penetrate into the interior, which increases the number of electrochemical reaction sites while effectively mitigating the volume expansion during lithiation and improving electrical conductivity. Thanks to the special structures, the discharge specific capacity of the Lithium-ion batteries (LIBs) based the coP/c as anode materials is 645.7 mAh g(-1) after 200 cycles at a current density of 200 mA g(-1). This work demonstrates that the coP/c has a great potential as a next generation anode material for LIBs.

关键词： coP c Porous nanostructure Anode materials Lithium-ion batteries

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