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Superior hydrogen generation from sodium borohydride hydrolysis catalyzed by the bimetallic co-Ru/c nanocomposite

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2021年第50期46卷 25376-25384页

作者： Huang, Wenkai Xu, Fuhua Liu, Xiang China Three Gorges Univ Engn Res Ctr Ecoenvironm Three Gorges Reservoir R Key Lab Inorgan Nonmetall Crystalline & Energy Co Coll Mat & Chem EngnMinist Educ Yichang 443002 Hubei Peoples R China

Sodium borohydride has been widely regarded as a promising hydrogen carrier owing to its greatly hydrogen storing capability (10.8 wt%), high weight density and excellent stability in alkaline solutions. Herein, we first design and synthesize a series of bimetallic M-Ru/c nanocomposites (including Fe-Ru/c, co-Ru/c, Ni-Ru/c and cu-Ru/c), via simply alloying of commercial Ru/c with nonprecious metal, for superior H2 evolution from the NaBH4 hydrolysis. The result exhibits that H2 generation is synergetically improved by alloying Ru/ c with co or Ni, while it is hindered by alloying Ru/c with Fe or cu. Indeed, co-Ru/c presents the highest efficient catalytic activity for H2 generation, with the TOF of 117.69 mol(H2)center dot molRu-1 center dot min-1, whereas Ru/c is only 57.08 mol(H2)center dot molRu-1 center dot min-1. In addition, the TOF of co-Ru/c reaches to 436.51 mol(H2)center dot molRu-1 center dot min-1 (96.7 L(H2)center dot gRu-1 center dot min-1) in the presence of NaOH. (c) 2021 Hydrogen Energy Publications LLc. Published by Elsevier Ltd. All rights reserved.

关键词： Sodium borohydride Hydrogen co-Ru c Bimetallic Hydrolysis

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THE INHIBITION OF PHOTOcHEMIcAL SMOG .9. MODEL-cALcULATIONS OF THE EFFEcT OF (c2H5)2NOH ON c2H4-NOX ATMOSPHERES

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ATMOSPHERIc ENVIRONMENT 1985年第4期19卷 597-605页

作者： HEIcKLEN, J PENN STATE UNIV CTR AIR ENVIRONM STUDIES UNIVERSITY PK PA 16802 USA

computer modeling of c2H4-NOx atmospheres with and without (c2H5)2NOH present were performed. The reaction scheme consists of 102 reactions and 45 reaction species plus N2, which is unreactive. No perceptible reaction occurs unless HNO2 is present, which can photodecompose to give HO radicals. HNO2 is produced from the reaction of H2O, NO and NO2. The equilibrium apparently is rapidly maintained through heterogeneous reactions. For systems with no H2O present, an artificial HO-source term must be included. A number of calculations for c2H4-NOx systems were made for conditions of various dilution factors, (c2H5)2NOH concentrations and feed rates, and various initial [NO]/[NO2] ratios. If NO2 is present initially it can photodecompose in air to produce a low level of O3 which in turn reacts with (c2H5)2NOH to give HO radicals. This can accelerate the onset of ultimate O3 formation. However, if sufficient (c2H5)2NOH is present or it is added before NO2 is produced, it delays O3 production. Under real atmospheric conditions which include dilution and diurnal variation in the sun''s intensity, 2nd-day effects are not important.

关键词： Photochemical smog diethylhydroxylamine model calculations environment modification c 2 H 4 -NO x atmospheres

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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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RELATIONAL DUALS OF THE c-MEANS cLUSTERING ALGORITHMS

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PATTERN REcOGNITION 1989年第2期22卷 205-212页

作者： HATHAWAY, RJ DAVENPORT, JW BEZDEK, Jc INFORMAT PROC LAB BOEING ELECTR CO SEATTLE WA 98124 USA

The hard and fuzzy c -means algorithms are widely used, effective tools for the problem of clustering n objects into (hard or fuzzy) groups of similar individuals when the data is available as object data, consisting of a set of n feature vectors in R P . However, object data algorithms are not directly applicable when the n objects are implicitly described in terms of relational data, which consists of a set of n 2 measurements of relations between each of the pairs of objects. New relational versions of the hard and fuzzy c -means algorithms are presented here for the case when the relational data can reasonably be viewed as some measure of distance. Some convergence properties of the algorithms are given along with a numerical example.

关键词： clustering Hard c -means algorithm Fuzzy c -means algorithm Pattern recognition

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Effect of Al addition on the single and cyclic ablation properties of c/c-Sic composites

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cERAMIcS INTERNATIONAL 2023年第4期49卷 6262-6269页

作者： Zhang, Haijun Liu, Lei Feng, Wei Guo, Yongchun Han, Qinxin Tang, chengwei Wang, Xinyu Xie, Yixin Xian Technol Univ Sch Mat & Chem Engn Xian 710021 Peoples R China

This article focuses on the damage behavior and mechanism of aluminum addition on reactive melt infiltrated c/ c-Sic composites in single and cyclic ablation environments. Plasma ablation tests were performed on c/c-Sic composites containing 20 wt % and 40 wt % aluminum respectively. coupled with TMA, XRD, SEM and EDS, the results showed that composites with 40 wt % Al had better ablation resistance during the cyclic ablation, while the composites with 20 wt % Al had excellent ablation damage resistance during a single ablation. This difference was due to higher number of microcracks formed inside the composites containing 40 wt % Al than 20 wt % Al, the lower specimen surface temperature during ablation, and the thermal stresses can be released by pore crack expansion during gas reciprocal loading. While in the single continuous loading of gas, the 20 wt % Al composite formed a protective oxide layer with smaller pores and fewer gas and oxygen entry channels, resulting in good resistance to ablation.

关键词： cyclic ablation Al addition c c-Sic Reactive melt infiltration

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Effects of spring fire and slope on the aboveground biomass, and organic c and N dynamics in a semi-arid grassland of northern china

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Journal of Arid Land 2019年第2期11卷 267-279页

作者： ZHAO Xiang HU Shuya DONG Jie REN Min ZHANG Xiaolin DONG Kuanhu WANG changhui College of Animal Science and Veterinary Medicine Shanxi Agricultural University State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing Institute of Science and Technology Information

The aboveground primary production is a major source of carbon(c) and nitrogen(N) pool and plays an important role in regulating the response of ecosystem and nutrient cycling to natural and anthropogenic disturbances. To explore the mechanisms underlying the effect of spring fire and topography on the aboveground biomass(AGB) and the soil c and N pool, we conducted a field experiment between April 2014 and August 2016 in a semi-arid grassland of northern china to examine the effects of slope and spring fire, and their potential interactions on the AGB and organic c and total N contents in different plant functional groups(c_3 grasses, c_4 grasses, forbs, Artemisia frigida plants, total grasses and total plants).The dynamics of AGB and the contents of organic c and N in the plants were examined in the burned and unburned plots on different slope positions(upper and lower). There were differences in the total AGB of all plants between the two slope positions. The AGB of grasses was higher on the lower slope than on the upper slope in July. On the lower slope, spring fire marginally or significantly increased the AGB of c_3 grasses, forbs, total grasses and total plants in June and August, but decreased the AGB of c_4 grasses and *** plants from June to August. On the upper slope, however, spring fire significantly increased the AGB of forbs in June, the AGB of c_3 grasses and total grasses in July, and the AGB of forbs and c_4 grasses in August. Spring fire exhibited no significant effect on the total AGB of all plants on the lower and upper slopes in 2014 and 2015. In 2016, the total AGB in the burned plots showed a decreasing trend after fire burning compared with the unburned plots. The different plant functional groups had different responses to slope positions in terms of organic c and N contents in the plants. The lower and upper slopes differed with respect to the organic c and N contents of c_3 grasses, c_4 grasses, total grasses, forbs, A. frigida plan

关键词： aboveground biomass plant functional group spring fire slope position N content organic c content semi-arid grassland

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Synthetic ablations in the c. elegans nervous system

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NETWORK NEUROScIENcE 2020年第1期4卷 200-216页

作者： Towlson, Emma K. Barabasi, Albert-Laszlo Univ Network Sci Inst Dept Phys NE Boston MA USA MIT Media Lab Cambridge MA USA Univ Network Sci Inst Dept Phys NE Boston MA USA Brigham & Women's Hosp Harvard Med Sch Dept Med Boston MA USA Univ Dept Network & Data Sci Cent European Budapest Hungary

Author Summary "Synthetic lethality" in cell biology is an extreme example of the effects of higher order genetic interactions: The simultaneous knockout of two or more individually nonessential genes leads to cell death. We define a neural analog to this concept in relation to the locomotor response to gentle touch in c. elegans. Two or more neurons are synthetic essential if individually they are not required for this behavior, yet their combination is. We employ a network control approach to systematically assess all pairs and triplets of neurons by their effect on body wall muscle controllability, and find that only surprisingly small sets of neurons are synthetic essential. They are highly localized in the nervous system and predicted to affect control over specific sets of muscles. Synthetic lethality, the finding that the simultaneous knockout of two or more individually nonessential genes leads to cell or organism death, has offered a systematic framework to explore cellular function, and also offered therapeutic applications. Yet the concept lacks its parallel in neuroscience-a systematic knowledge base on the role of double or higher order ablations in the functioning of a neural system. Here, we use the framework of network control to systematically predict the effects of ablating neuron pairs and triplets on the gentle touch response. We find that surprisingly small sets of 58 pairs and 46 triplets can reduce muscle controllability in this context, and that these sets are localized in the nervous system in distinct groups. Further, they lead to highly specific experimentally testable predictions about mechanisms of loss of control, and which muscle cells are expected to experience this loss.

关键词： c elegans Graph theory Network control theory Neuronal ablations Synthetic lethality

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Sulfur-based mixotrophic denitrification with the stoichiometric S⁰/N ratio and methanol supplementation: effect of the c/N ratio on the process

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JOURNAL OF ENVIRONMENTAL ScIENcE AND HEALTH PART A-TOXIc/HAZARDOUS SUBSTANcES & ENVIRONMENTAL ENGINEERING 2021年第13期56卷 1420-1427页

作者： Yanez, Diana Guerrero, Lorna Borja, Rafael Huilinir, cesar Univ Santiago Chile Dept Ingn Quim Ave Libertador Bernardo OHiggins 3363 Santiago Chile Univ Tecn Federico Santa Maria Dept Ingn Quim & Ambiental Valparaiso Chile Inst Grasa CSIC Campus Univ Pablo de Olavide Seville Spain

The impact of the organic carbon to nitrate ratio (c/N ratio) on mixotrophic denitrification rate has been scarcely studied. Thus, this work aims to investigate the effect of the c/N ratio on the mixotrophic denitrification when methanol is used as a source of organic matter and elemental sulfur as an electron donor for autotrophic denitrification. For this, two initial concentrations of NO3--N (50 and 25 mg/L) at a stoichiometric ratio of S-0/N, and four initial c/N ratios (0, 0.6, 1.2, and 1.9 mg cH3OH/mg NO3- -N) were used at 25 (+/- 2) degrees c. The results showed that when using a c/N ratio of 0.6, the highest total nitrogen removal was obtained and the accumulation of nitrites was reduced, compared to an autotrophic system. The most significant contribution to nitrate consumption was through autotrophic denitrification (AuDeN) for a c/N ratio of 0.6 and 1.2, while for c/N = 1.9 the most significant contribution of nitrate consumption was through heterotrophic denitrification (HD). Finally, organic supplementation (methanol) served to increase the specific nitrate removal rate at high and low initial concentrations of substrate. Therefore, the best c/N ratio was 0.6 since it allowed for increasing the removal efficiency and the denitrification rate.

关键词： Mixotrophic denitrification c N ratio sulfur-based mixotrophic denitrification

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The response of c/N/S cycling functional microbial communities to redox conditions in shallow aquifers using in-situ sediment as bio-trap matrix

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ENVIRONMENTAL TEcHNOLOGY 2024年第18期45卷 3666-3678页

作者： Li, cui chen, Rong Ouyang, Weiwei Xue, chen Liu, Minghui Liu, Hui China Univ Geosci Sch Environm Studies Hubei Key Lab Yangtze Catchment Environm Aquat Sci 388 Lumo Rd Wuhan 430074 Peoples R China China Univ Geosci State Key Lab Biogeol & Environm Geol Wuhan 430078 Hubei Peoples R China Hubei Ecol Polytech Coll Wuhan Peoples R China Wuhan Technol & Business Univ Sch Environm & Biol Engn Wuhan Peoples R China

Microbial communities are fundamental components driving critical biogeochemical carbon (c), nitrogen (N) and sulfur (S) cycles in groundwater ecosystems. The reduction-oxidation (redox) potential is one important environmental factor influencing the microbial community composition. Here, we developed a bio-trap method using in-situ sediment as a matrix to collect aquifer sediment samples and evaluate the response of microbial composition and c/N/S cycling functions to redox variations created by providing sole O-2, joint O-2 and H-2, and sole H-2 to three wells. Illumina sequencing analyses showed that the microbial communities in the bio-trap sediment could respond quickly to redox changes in the wells, demonstrating that this bio-trap method is promising for detecting microbial variation in the aquifer sediment. The microbial metabolic functions related to c, N and S cyclings and organic pollutants degradation were predicted by the Kyoto Encyclopedia of Genes and Genomes (KEGG) approach. It was found that the joint O-2 and H-2 injection produced medium oxidation-reduction potential (ORP -346 and -614 mV) and enhanced more microbial functions than sole O-2 or H-2,H- which mainly include oxidative phosphorylation, most carbon source metabolism, various pollutants degradation, and nitrogen and sulfur metabolism. Moreover, the functional genes encoding phenol monooxygenase, dioxygenase, nitrogen fixation, nitrification, aerobic and anaerobic nitrate reductase, nitrite reductase, nitric oxide reductase, and sulfur oxidation increased. These findings tell us the contaminant bioremediation and N, S metabolism can be promoted by adjusting ORP realised by injecting joint O-2 and H-2.

关键词： Bio-trap microbial community functional genes c N S metabolism redox conditions

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