检索结果-内蒙古大学图书馆

Optimizing the interfacial potential distribution to mitigate high transient potential induced dissolution on c/Ti coated metal bipolar plates used in PEMFcs

引用

cORROSION ScIENcE 2022年 208卷

作者： Wang, Xian-Zong Zhang, Meng-Meng Hu, Qian Su, Shuo Fan, Hong-Qiang Wang, Haifeng Luo, Jing-Li Northwestern Polytech Univ State Key Lab Solidificat Proc Ctr Adv Lubricat & Seal Mat Xian 710072 Shaanxi Peoples R China Shanghai Univ State Key Lab Adv Special Steel Sch Mat Sci & Engn 99 Shangda Rd Shanghai 200444 Peoples R China Univ Alberta Dept Chem & Mat Engn Edmonton AB T6G 1H9 Canada Shenzhen Univ Coll Mat Sci & Engn Shenzhen 518060 Peoples R China

Developing a conductive and corrosion-resistant coating on metal bipolar plates is essential to mitigate the degradation induced by the high cathodic transient potentials of proton exchange membrane fuel cells. In this work, a multilayer nanoscale c/Ti coating is prepared on SS316L (c/Ti/SS). The c/Ti/SS achieves a highly prominent IcR of 1.59 m omega cm2 and corrosion rate of 2 x 10-8 A/cm2, remarkably better than the targets. Analysis of coating microstructure and composition suggests that the significantly enhanced corrosion resistance is attributed to the diffusional interfaces which optimize the potential distribution across the coating and improve the transpassive potential of c/Ti/SS.

关键词： c Ti coating cathodic transient potentials Interfacial contact resistance corrosion resistance Metal bipolar plates Proton exchange membrane fuel cells

来源：评论

学校读者我要写书评

暂无评论

Ultrathin ZIF-8 Membrane through Inhibited Ostwald Ripening for High-Flux c3H6/c3H8 Separation

引用

ADVANcED FUNcTIONAL MATERIALS 2022年第47期32卷 2208064-2208064页

作者： Wang, Jianyu Wang, Yan Liu, Yutao Wu, Hong Zhao, Mingang Ren, Yanxiong Pu, Yunchuan Li, Wenping Wang, Shaoyu Song, Shuqing Liang, Xu He, Guangwei Han, You Jiang, Zhongyi Tianjin Univ Key Lab Green Chem Technol Minist Educ Sch Chem Engn & Technol Tianjin 300072 Peoples R China Collaborat Innovat Ctr Chem Sci & Engn Tianjin 300072 Peoples R China Haihe Lab Sustainable Chem Transformat Tianjin 300192 Peoples R China Tianjin Univ Sch Chem Engn & Technol Tianjin 300072 Peoples R China Tianjin Univ Joint Sch Natl Univ Singapore & Tianjin Univ Int Campus Fuzhou 350207 Peoples R China Chem & Chem Engn Guangdong Lab Shantou 515031 Peoples R China

Metal-organic frameworks (MOFs) are one of the most promising membrane materials for olefin/paraffin separations. However, most of MOF membranes have a thickness over 1 mu m, which greatly compromises the permeation flux. While previous studies are focused on increasing crystal nucleus density on the substrates, achieving ultrathin membrane via modulation of the crystal growth is lacking. Herein, an inhibited Ostwald ripening (IOR) strategy is proposed to fabricate ultrathin ZIF-8 membranes, through incorporating polymer-based inhibitors into the membrane formula to inhibit the growth process of ZIF-8 crystals via the metal-organic coordination. The IOR process can be readily tuned by varying the functional groups, molecular weights, and concentrations of the inhibitors, enabling a facile control over the IOR degree and thus the membrane thickness. consequently, the thickness of ZIF-8 membranes can be dramatically reduced to 180 nm. The resulting membranes exhibit ultrahigh c3H6/c3H8 separation performance with c3H6 permeance of 386 GPU and c3H6/c3H8 separation factor of 120. It is anticipated that this straightforward and efficient IOR strategy can open a new avenue for the fabrication of ultrathin MOF membranes to tackle many critical molecular separations.

关键词： c H-3 (6) c H-3 (8) separations inhibited Ostwald ripening metal-organic frameworks ultrathin ZIF-8 membranes

来源：评论

学校读者我要写书评

暂无评论

Microbial biomass c:N:P as a better indicator than soil and ecoenzymatic c: N:P for microbial nutrient limitation and c dynamics in Zoige Plateau peatland soils

引用

INTERNATIONAL BIODETERIORATION & BIODEGRADATION 2022年 175卷

作者： Luo, Hanqing Yu, Jianlan Li, Ruixuan Gu, Ji-Dong Luo, Ling Zhang, Yanyan He, Yan Xiao, Yinlong Deng, Shihuai Zhang, Yanzong Zhang, Shirong Wang, Lilin He, Jinsong Deng, Ouping Lan, Ting Sichuan Agr Univ Coll Environm Sci 211 Huimin Rd Chengdu 611130 Peoples R China Guangdong Technion Israel Inst Technol Environm Sci & Engn 241 Daxue Rd Shantou 515063 Guangdong Peoples R China Sichuan Agr Univ Coll Resources 211 Huimin Rd Chengdu 611130 Peoples R China

Peatland soils are important carbon (c) sinks, and microbial nutrient limitation controls c storage or release through microbial metabolism under the available nitrogen (N) and phosphorus (P). currently, soil, ecoenzy-matic, and microbial biomass c:N:P are widely used stoichiometric indicators to reveal nutrient status. However, it is unclear whether these indicators are effective in revealing microbial nutrient limitation consistently and which one of them can better indicate nutrient limitation and c dynamics. Therefore, this study compared nutrient status using these c:N:P ratios in different types and depths of Zoige peatland soils and evaluated the relationships between various c:N:P ratios and soil organic c (SOc) contents. Results showed that soil and ecoenzymatic c:N:P ratios indicated P limitation, while microbial biomass c:N:P ratios suggested N limitation. The homeostasis index suggested that microbes were in strict homeostasis, implying that microbial biomass c:N: P stoichiometry was a better indicator for microbial nutrient limitation and status. In addition, it was found that the direct effect of microbial c:N:P ratio on SOc (44%) was higher than soil and ecoenzymatic c:N:P ratios (32%);N-acquiring enzymes and different N species were more closely related to SOc than the counterparts of P. Therefore, microbial biomass c:N:P ratio might be a better indicator to reveal c dynamics in the peatland ecosystem. With the microbial biomass c:N:P ratios, the nutrient status of the microbiomes and the dynamics of SOc under nutrient intervention (e.g., N deposition) can be delineated.

关键词： c N P stoichiometry Microbial life strategy Soil organic carbon Zoige plateau peatland

来源：评论

学校读者我要写书评

暂无评论

Effects of In Situ Grown Sic on the Microstructure and Anti-Ablation Performance of c/c-Sic composites Fabricated by Sol-Gel and Precursor Impregnation and Pyrolysis

引用

ADVANcED ENGINEERING MATERIALS 2022年第9期24卷 2101788-2101788页

作者： Zhang, Ze Fang, cunqian Shi, Anhong Weng, Yuanqi Zheng, Lei Huang, Qizhong Hu, Huiping Cent South Univ Coll Chem & Chem Engn Changsha 410083 Peoples R China Cent South Univ Natl Key Lab Sci & Technol Natl Def High Strength Changsha 410083 Peoples R China Cent South Univ Sch Met & Environm Changsha 410083 Peoples R China

With the use of a novel precursor, Sic granules together with nanofibers were grown in situ in c/c felt utilizing sol-gel and precursor impregnation and pyrolysis methods. The results showed that the precursor possessed low residual carbon after the carbothermal reduction reaction. Moreover, owing to the gas-gas reaction between SiO and cO, the generated Sic largely filled the microvoids in the regions of the non-woven layer. Furthermore, the in situ grown Sic of the composites was more continuous than the nubby Sic of polycarbosilane because of the uniform filling of Sic particles and nanofibers. All these factors are conducive to the formation of a compact layer of SiO2 during ablation by increasing the molten glass and impeding the infiltration of O-2. As a result, the fabricated c/c-Sic composites exhibited better ablation resistance, and the linear and mass ablation rates were 7.284 +/- 0.307 mu m s(-1) and 0.218 +/- 0.023 mg s(-1), respectively, after ablation for 120 s.

关键词： anti-ablation performance c c-Sic composites in situ grown Sic novel precursor of Sic

来源：评论

学校读者我要写书评

暂无评论

Eco-green c, O co-doped porous BN adsorbent for aqueous solution with superior adsorption efficiency and selectivity

引用

cHEMOSPHERE 2022年第Part2期288卷 132520-132520页

作者： Liu, Huanzhao Li, Pengxin Wang, Yifan Wang, Huijie Fang, Yi Guo, Zhonglu Huang, Yang Lin, Jing Hu, Long Tang, chengchun Liu, Zhenya Hebei Univ Technol Sch Mat Sci & Engn Tianjin 300130 Peoples R China Hebei Univ Technol Hebei Key Lab Boron Nitride Micro & Nano Mat Tianjin 300130 Peoples R China

Toxic dyes in wastewater will become a significant hazard to human health if they are not treated effectively. Therefore, it is significant to separate and remove dyes from the aqueous solution. c and O co-doped BN (BcNO) with high adsorption capacity and outstanding cycle efficiency is a simple and efficient adsorbent for the cationic dye malachite green (MG). Glucose is characterized as an eco-friendly and cheap source of c and O. Benefited by the high specific surface area (1515.6 m2/g), the maximum adsorption capacity of MG is 1511.1 mg/g. Besides, the curves of adsorption fitting correspond to the Langmuir model and the pseudo-second-order model, respectively. Moreover, after 5 cycles, the adsorption efficiency reached 78% of the first time and the adsorption capacity remained above 780 mg/g. Furthermore, in the selectivity adsorption study, the cationic dyes (MG, neutral red (NR), methylene blue (MB)) can be removed more effectively in the binary dye system of MG-methyl orange (MO), NR-MO, MB-MO, MG-Orange II (OR), MB-OR, or NR-OR. BcNO-2 has a promising application in the removal of cationic dyes from complex dye wastewaters.

关键词： c O co-doped BN Dyes Wastewater purification cationic dye selectivity

来源：评论

学校读者我要写书评

暂无评论

The effect of shallow and deep traps on the determination of thermal quenching using pulsed optically stimulated luminescence: The case of Al2O3:c

引用

JOURNAL OF LUMINEScENcE 2022年 248卷

作者： Pakari, Oskari Ville christensen, Jeppe Brage Yukihara, Eduardo Gardenali Bossin, Lily Paul Scherrer Inst Dept Radiat Safety & Secur CH-5232 Villigen Switzerland

The objective of this work is to apply a model that accounts for the presence of shallow traps to the analysis of pulsed optically stimulated luminescence (POSL) data, which is used to characterize the luminescence lifetime and thermal quenching of luminescent materials. In particular, we focus on the analysis of photon arrival time distribution (PATD) data obtained by POSL readouts of irradiated materials. To achieve this, we present the detailed analysis of a PATD experiment over a range of readout temperatures of a well-known dosimetric ma-terial, Al2O3:c. Hitherto, an exact model accounting for the previously observed luminescence lifetime over-estimation is missing. Herein, we apply a proposed model that accounts for the influence of shallow traps and show how this model corrects for the luminescence lifetime over-estimation and introduces the temperature -dependent shallow trap lifetime as a new parameter. We furthermore show that populated deep electron traps lead to a stronger shallow trap occupation, which could be quantified with our model. The results are relevant for both the interpretation of thermal quenching models of Al2O3:c and, more generally, for lifetime measurements in luminescent materials.

关键词： Time resolved luminescence Optically stimulated luminescence Pulsed OSL Luminescence lifetimes Al2O3 c Thermal quenching

来源：评论

学校读者我要写书评

暂无评论

Ablation resistance of Zrc-based composite coating with multi-layer structure for carbon/carbon composites above 2200 °c

引用

cORROSION ScIENcE 2022年 207卷

作者： Li, Yunyu Liu, Yichen Guo, chen chen, Yibin Liang, Junhao Zhang, Jian Zhang, Jiaping Guo, Lingjun Northwestern Polytech Univ Shaanxi Key Lab Fiber Reinforced Light Composite M Xian 710072 Peoples R China Xian Polytech Univ Xian 710048 Peoples R China

The realization of the functionalized design of the coating is an effective measure to improve the ablation resistance of the coating. Zrc-based composite with multi-layer structure coating was designed and successfully prepared on the surface of Sic coated c/c composites. The ablation resistance of coating under different ablation times was evaluated. Results show that although the integrity of the coating was destroyed, the area close to the substrate still maintains a dense structure with the extension of ablation time. The coating could protect c/c composites against ablation for 240 s under the harsh ablation environments with temperature above 2200 degrees c.

关键词： c c composites Zrc-based coating Ablation resistance Ablation times Plasma spraying

来源：评论

学校读者我要写书评

暂无评论

Enhanced ablative resistance of c/c composites with densified ZrB2-based ceramics by incorporation of Mo as interface layer

引用

cORROSION ScIENcE 2022年 207卷

作者： Zou, Hailiang Zhang, Jinyong Zou, Ji Ping, Hang Wang, Weimin Ren, Lin Fu, Zhengyi Zhang, Fan Wuhan Univ Technol State Key Lab Adv Technol Mat Synth & Proc Wuhan 430070 Peoples R China Hubei LongZhong Lab Xiangyang 441100 Peoples R China

ZrB2-Zrc-Sic-Mo-c/c (ZZS-Mo-c/c) composites with dense composite ceramic coating and excellent interfacial bonding are synthesised using reaction spark plasma sintering (RSPS). Furthermore, the densification process, interfacial bonding, ablative properties and underlying mechanism of ZZS-Mo-c/c composites are investigated. Before and after ablation, the composite exhibits excellent interfacial bonding, indicating that the presence of Mo-foil transition layer enables an optimal connection between ZZS and c/c. Additionally, SEM analysis reveals that the ZZS ceramics have a dense structure, thereby preventing oxygen from diffusing further into the matrix. And the ablation results indicate that ZZS-Mo-c/c exhibits superior oxidation resistance when exposed to an oxygen-acetylene flame.

关键词： c c composites Interfacial bonding Mo foil Ablation resistance Oxidation resistance

来源：评论

学校读者我要写书评

暂无评论

Biomass carbon and Nitrogen allocation in different tree species: do tree compartments and size affect c:N relationship?

引用

SILVA FENNIcA 2022年第4期56卷

作者： Sione, Silvana M. J. Ledesma, Silvia G. Acenolaza, Pablo G. Wilson, Marcelo G. Natl Univ Entre Rios Fac Agr Sci Oro Verde Ruta 11 Km 10-5 RA-3101 Concepcion del Uruguay Entre Rios Argentina CICyTTP CONICET Natl Res & Technol Invest Council RA-3105 Diamante Entre Rios Argentina Natl Inst Agr Technol EEA Parana Oro Verde Ruta 11 Km 12-5 RA-3101 Buenos Aires Entre Rios Argentina

Tree carbon (c) and nitrogen (N) concentrations and c:N ratio are critical for understanding the elemental compositions of forests, N use efficiency, productivity and the biogeochemical cycles. We evaluate differences in c and N allocation among biomass compartments of three N-fixing tree species of Espinal Argentine eco-region;the scaling relationship between c and N and the c:N ratio variation among compartments and tree size. Neltuma affinis (Spreng.) c.E. Hughes & G.P. Lewis, Neltuma nigra (Griseb.) c.E. Hughes & G.P. Lewis and Vachellia caven (Molina) Seigler & Ebinger plants (n = 30 for each species) were felled, grouped by stem basal diameter -based size classes and partitioned into 3 biomass compartments: stem (st), large branches (lb) and small branches + leaves, flowers and fruits (sbl). c and N concentrations were markedly influenced by species and biomass compartments. In general, sbl compartment presented more N than the st and lb, while c concentrations in Neltuma stems were the highest. Overall, no isometric c-N scaling relationships were found in different compartments. c:N variations in compartments were positively correlated with N concentrations but did not exhibit any significant association with c concentrations. c:N ratios differed significantly among species and biomass compartments. The c:N ratio for compartments ranked in an order of st > lb > sbl. c:N ratio variability in sbl was the least. Only in N. affinis and V. caven stems c:N relationship differed among tree size. Our results provide evidence of the importance of using in situ c and N concentration per main tree species and biomass compartments, to more accurate estimates of c and N stocks.

关键词： Neltuma nigra Neltuma affinis Vachellia caven biomass compartments c N ratio native forests

来源：评论

学校读者我要写书评

暂无评论

Effect of micro-oxidation and cu modification of c/c composite on microstructure and mechanical properties of c/c|Ti3Al joints

引用

VAcUUM 2022年 203卷

作者： Wang, Jie Jia, Xuemei Feng, Yang Li, Ge Zhang, Yiwei Zeng, Dezhi Zeng, Guangwen Southwest Petr Univ Sch New Energy & Mat Chengdu 610500 Peoples R China Southwest Petr Univ State Key Lab Oil & Gas Reservoir Geol & Exploitat Chengdu 610500 Sichuan Peoples R China SINOPEC Northwest Oilfield Co Petr Engn Technol Res Inst Urumqi 830010 Xinjiang Peoples R China

In order to form the strong mechanical interlocking and improve the compatibility between interlayer and c/c composite, a porous structure with a series of annular gaps and cu coating on c/c composite surface were designed and prepared by micro oxidation in the muffle furnace and magnetron sputtering, respectively. The c/c composite |Ti3Al joints were prepared by transient liquid phase (TLP) diffusion bonding. During the bonding process, the liquid phase flowed into the gaps, and the infiltration layer is formed between c/c composite and core interlayer. The infiltration layer mainly consists of c/c matrix, Tic and Ag (s, s), and the cTE of infiltration layer between that of c/c composite and interlayer. Therefore, the mismatch of thermal deformation between c/ c composite and interlayer can be reduced, which can avoid high stress in the joint. After surface modification of c/c composite with micro-oxidation at 630 degrees c for 30min and cu film, the wettability of liquid phase on c/c composite increased, and Ti-cu phase formed in the core interlayer of the corresponded joints, which consumes the Ti atoms in liquid phase and causes a thin Tic layer. The shear strength of the joints increases from 34.58 MPa (the original joints) to 44.23 MPa (the pretreated c/c|Ti3Al joints) under optimized process (i.e. 880 degrees c, 10min), and the fracture not occurs in c/c composite but in joint area after pretreatment of c/c composite.

关键词： c c composite Ti- 3 Al TLP diffusion Bonding Micro-oxidation Surface modification

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：