Local Joule heating targets catalyst surface for hydrocarbon combustion

Qian Xiong,Xingbao Zhu,Ri He,Xueyi Mei,Yexin Zhang,Zhicheng Zhong,Wei Zhao,Weiming Nie,Jian Zhang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.117 No.-

Most industrial catalytic reactions are achieved by external heating and catalysts are entirely heated tooffer enough thermal energy to surface active sites. However, there is an inherent drawback that mostinput energy is dissipated into the bulk while minor is donated to the surface, leading to high energywaste. Here, we proposed a so-called local Joule heating method via passing an electric current throughpacked catalyst nanoparticles with a large contact resistance, which can generate sufficient heat to targetat the surface region. We selected hydrocarbon combustion, a common way to eliminate unburned pollutants,as a probe reaction and used the conductive antimony-doped tin oxide (ATO) as a model catalyst. Compared with traditional external heating, this method consumed one order lower energy input,reduced the macroscopically average temperature for same conversion by 100 C, improved the durabilitywith smaller activity loss within 100 h operation, and suppressed water poisoning effect by 60 %. Also, the combustion was sparked in seconds by pulsing electric current into the catalyst bed, allowing anapplication in prompt treatment of leaked hydrocarbons. The local Joule heating between contactednanoparticles, which could focus thermal energy on catalyst surface, is prospective to improve catalysisefficiency.

미디어 콘텐츠 시청과 대인커뮤니케이션이 조기연애 인식형성에 미치는 영향: 중국동포 청소년을 중심으로

김천웅(Qian Xiong),박만수(Man Su Park) 한국디지털콘텐츠학회 2022 한국디지털콘텐츠학회논문지 Vol.23 No.5

Feature analysis on air quality in the main urban area of Nanchong City in 2015–2018

Xiong Lei,Qing Zheng,Yifan Qian,Jian Hu,Danyu Li,Ping Zhang,Xu Yuan,Qiumei Quan,Yunxiang Li 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.3

This study evaluates the air quality in Nanchong City in 2015–2018 based on automatic monitoring data and meteorological data in the main urban area. Results show that overall air quality in the main urban area of Nanchong was standard and improved from 2015 to 2018. SO₂, NO₂, and CO had slight influences on air quality in the study area, whereas excessive annual average PM2.5 and increasing O₃ concentration challenged the air quality. The monthly average mass concentrations of particulate matters (PM2.5 and PM10), NO₂, and CO generally presented a “U-shaped” distribution pattern while O₃ showed the opposite. The diurnal variation of PM, NO₂, and CO has two peaks related to the morning and evening rush hours. Vehicle exhaust is the main source of local pollution. Over-standard PM2.5 can significantly inhibit O₃ production while O₃ can easily promote the secondary generation of PM2.5 due to its strong oxidization. PM2.5 emission should be controlled strictly in winter, while in summer, the sources of O₃ should be controlled vigorously. Air pollution is comprehensive and complicated and is influenced by various factors, mainly meteorological and human factors. Measures such as artificial rainfall should be included at the appropriate time to cope with adverse meteorological conditions when heavy pollution occurs in winter.

Cathodic reduction characteristics of 2-chloro-4-nitrophenol in microbial electrolysis cell

Qianli Yu,Wei Xiong,Donggen Huang,Cui Luo,Qiang Yang,Tao Guo,Qi Wei 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.6

Microbial electrolysis cell (MEC) has been constructed to study the degradation characters of 2-chloro-4-nitrophenol (2C4NP) in waste water. The effects of applied voltage, initial concentration of substrate and co-matrix species on the reduction and degradation of 2C4NP were studied. Qualitative and quantitative analysis of 2C4NP residues and degradation intermediate by using UV-Vis, HPLC, HPLC/MS/MS, IC and other analytical testing techniques. The degradation mechanism of 2C4NP in MEC cathode was proposed. The results showed that electron and electroactive microorganisms would produce coupling effect and accelerate the degradation of 2C4NP under adding 0.5 V DC; Under the condition of satisfying the C/N ratio of electroactive anaerobic microorganism, the addition of organic substances such as glucose and sodium acetate which were easily degraded by microorganisms would hinder the degradation of 2C4NP in the cathode compartment. 2C4NP can be effectively degraded by adding appropriate amount of glucose as carbon source with the low C/N. 2C4NP undergoes reduction, dechlorination, denitrification and assimilation in the cathode compartment to form 2-chloro-4-aminophenol, 4-aminophenol, 2-chlorophenol, 2-chloro-4-hydroxyphenol, nitrophenol, hydroquinone, 4-hydroxyhexadienoic acid semialdehyde, valeric acid, oxalic acid and many other intermediate products. According to the degradation intermediates, the degradation mechanism of 2C4NP in the cathode compartment was presumed.

ON THREE SPECTRAL REGULARIZATION METHODS FOR A BACKWARD HEAT CONDUCTION PROBLEM

Xiong, Xiang-Tuan,Fu, Chu-Li,Qian, Zhi Korean Mathematical Society 2007 대한수학회지 Vol.44 No.6

We introduce three spectral regularization methods for solving a backward heat conduction problem (BHCP). For the three spectral regularization methods, we give the stability error estimates with optimal order under an a-priori and an a-posteriori regularization parameter choice rule. Numerical results show that our theoretical results are effective.

The inhibitory effect of pyrogallol on tyrosinase activity and structure: Integration study of inhibition kinetics with molecular dynamics simulation

Xiong, Shang-Ling,Lim, Gyu Tae,Yin, Shang-Jun,Lee, Jinhyuk,Si, Yue-Xiu,Yang, Jun-Mo,Park, Yong-Doo,Qian, Guo-Ying Elsevier 2019 INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES Vol.121 No.-

<P><B>Abstract</B></P> <P>Pyrogallol is naturally found in aquatic plant and has been proposed as a substrate of tyrosinase. In this study, we evaluated the dual effect of pyrogallol on tyrosinase as an inhibitor in the presence of L‑DOPA simultaneously via integrating methods of enzyme kinetics and computational molecular dynamics (MD) simulations. Pyrogallol was found to be a reversible inhibitor of tyrosinase in the presence of L‑DOPA and its induced mechanism was the parabolic non-competitive inhibition type (<I>IC</I> <SUB>50</SUB> = 0.772 ± 0.003 mM and <I>K</I> <SUB>i</SUB> = 0.529 ± 0.022 mM). Kinetic measurements by real-time interval assay showed that pyrogallol induced rapid inactivation process composing with slight activations at the low dose. Spectrofluorimetry studies showed that pyrogallol mainly induced regional changes in the active site of tyrosinase accompanying with hydrophobic disruption at high dose. The computational MD simulations further revealed that pyrogallol could interact with several residues near the tyrosinase active site pocket such as HIS61, HIS85, HIS259, ASN260, HIS263, VAL283, and ALA296. Our study provides insight into the mechanism by which hydroxyl group composing pyrogallol inhibit tyrosinase and pyrogallol is a potential natural anti-pigmentation agent.</P>

MODEL PREDICTIVE TRAJECTORY OPTIMIZATION AND TRACKING IN HIGHLY CONSTRAINED ENVIRONMENTS

Lu Xiong,Zhiqiang Fu,Zixuan Qian,Bo Leng,Dequan Zeng,Yanjun Huang 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.4

This paper presents a model predictive trajectory optimization and tracking framework to avoid collisions for autonomous vehicles in highly constrained environments. Firstly, a vehicle model is established in road coordinate system to describe the relationship between the vehicle and the reference road. Secondly, a numerical optimization method is applied to smoothen the reference path generated by waypoints. Then, a multilayer searched method is used to establish a safe driving corridor in highly constrained environments. In addition, an optimal path optimization and tracking framework based on model predictive control is formulated to improve the driving safety and comfort. The proposed framework considers the constraints of path boundaries and vehicle dynamics to provide the optimal control command. Furthermore, the speed profile is optimized based on the longitudinal motion model in space domain to ensure the constraints of speed limits and vehicle acceleration. Finally, the proposed algorithms are evaluated through experiments in various scenarios to demonstrate the effectiveness.

Description of Corynebacterium poyangense sp. nov., isolated from the feces of the greater white-fronted geese (Anser albifrons)

Liu Qian,Fan Guoying,Wu Kui,Bai Xiangning,Yang Xi,Song Wentao,Chen Shengen,Xiong Yanwen,Chen Haiying 한국미생물학회 2022 The journal of microbiology Vol.60 No.7

Two novel Gram-positive, non-spore-forming, facultatively anaerobic, non-motile, and short rods to coccoid strains were isolated from the feces of the greater white-fronted geese (Anser albifrons) at Poyang Lake. The 16S rRNA gene sequences of strains 4H37-19T and 3HC-13 shared highest identity to that of Corynebacterium uropygiale Iso10T (97.8%). Phylogenetic and phylogenomic analyses indicated that strains 4H37-19T and 3HC-13 formed an independent clade within genus Corynebacterium and clustered with Corynebacterium uropygiale Iso10T. The average nucleotide identity and digital DNA-DNA hybridization value between strains 4H37-19T and 3HC-13 and members within genus Corynebacterium were all below 95% and 70%, respectively. The genomic G + C content of strains 4H37-19T and 3HC-13 was 52.5%. Diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylinositol (PI), phosphatidylcholine, and phosphatidyl inositol mannosides (PIM) were the major polar lipids, with C18:1ω9c, C16:0, and C18:0 as the major fatty acids, and MK-8 (H4), MK-8(H2), and MK-9(H2) as the predominant respiratory quinones. The major whole cell sugar was arabinose, and the cell wall included mycolic acids. The cell wall peptidoglycan contained meso-diaminopimelic acid (meso-DAP). The polyphasic taxonomic data shows that these two strains represent a novel species of the genus Corynebacterium, for which the name Corynebacterium poyangense sp. nov. is proposed. The type strain of Corynebacterium poyangense is 4H37-19T (=GDMCC 1.1738T = KACC 21671T).

Progress in the Study of Coastal Storm Deposits

Haixian Xiong,Guangqing Huang,Shuqing Fu,Peng Qian 한국해양과학기술원 2018 Ocean science journal Vol.53 No.2

Numerous studies have been carried out to identify storm deposits and decipher storm-induced sedimentary processes in coastal and shallow-marine areas. This study aims to provide an in-depth review on the study of coastal storm deposits from the following five aspects. 1) The formation of storm deposits is a function of hydrodynamic and sedimentary processes under the constraints of local geological and ecological factors. Many questions remain to demonstrate the genetic links between storm-related processes and a variety of resulting deposits such as overwash deposits, underwater deposits and hummocky cross-stratification (HCS). Future research into the formation of storm deposits should combine flume experiments, field observations and numerical simulations, and make full use of sediment source tracing methods. 2) Recently there has been rapid growth in the number of studies utilizing sediment provenance analysis to investigate the source of storm deposits. The development of source tracing techniques, such as mineral composition, magnetic susceptibility, microfossil and geochemical property, has allowed for better understanding of the depositional processes and environmental changes associated with coastal storms. 3) The role of extreme storms in the sedimentation of low-lying coastal wetlands with diverse ecosystem services has also drawn a great deal of attention. Many investigations have attempted to quantify widespread land loss, vertical marsh sediment accumulation and wetland elevation change induced by major hurricanes. 4) Paleostorm reconstructions based on storm sedimentary proxies have shown many advantages over the instrumental records and historic documents as they allow for the reconstruction of storm activities on millennial or longer time scales. Storm deposits having been used to establish proxies mainly include beach ridges and shelly cheniers, coral reefs, estuary-deltaic storm sequences and overwash deposits. Particularly over the past few decades, the proxies developed from overwash deposits have successfully retrieved many records of storm activities during the mid to late Holocene worldwide. 5) Distinguishing sediments deposited by storms and tsunamis is one of the most difficult issues among the many aspects of storm deposit studies. Comparative studies have investigated numerous diagnostic evidences including hydrodynamic condition, landward extent, grain property, texture and grading, thickness, microfossil assemblage and landscape conformity. Perhaps integrating physical, biological and geochemical evidences will, in the future, allow unambiguous identification of tsunami deposits and storm deposits.

Formula optimization for melanosis-inhibitors of Pacific white shrimp (Litopenaeus vannamei) by response surface methodology

Yun-Fang Qian,Qing Xiong,Sheng-Ping Yang,Jing Xie 한국식품과학회 2019 Food Science and Biotechnology Vol.28 No.6

Melanosis is major problem of crustaceans duringtheir rigor mortis storage. This study for the firsttime was designed to optimize the formula of preservativesto maintain the color feature of Pacific white shrimp usingresponse surface methodology. A three-factors-three-levelsBox-Behnken design was applied to evaluate the effect ofchitosan, citric acid and L-cysteine on color features (L*,a*, b* and DE) of Pacific white shrimp. It was found thatthe increasing rate of DE was retarded by the higher concentrationsof chitosan, citric acid and L-cysteine in acertain range. The optimal formula for inhibiting theincrease of DE was 1.36% chitosan, 0.47% citric acid and0.31% L-cysteine. Under the optimal pretreated conditions,the predicted DE of shrimp after 8 days of storage was14.59, close to the measured values (14.49). These resultsindicated that the optimal combined preservatives couldretard the decrease of lightness and the aggregation of DEand melanosis effectively, and might be a potentialapplication for retarding melanosis and extending shelf lifeof Pacific white shrimp.