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Study on S-shaped characteristic of Francis reversible unit by on-site test and CFD simulation

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Science China(Technological Sciences) 2013年第9期56卷 2163-2169页

作者： li jinwei HU QingJuan YU JiXing li QiZhang Institute of Water Resources and Hydropower Research Baoquan Pumped-storage limited Company of Henan State Grid

The operation parameters （vibration, shaft displacement and pressure fluctuation） of No. 1 Francis reversible unit of Baoquan pumped-storage power station were measured on site in the no-load mode at net heads of 518.04, 522.01 and 530.38 m, re- spectively. The rotational speed fluctuations in the no-load mode at three net heads were beyond synchronization requirement with obvious S-shaped characteristic, and misaligned guide vanes （MGV） had to be put into use for synchronization. Further analysis demonstrated that the rotating frequency signal was generally dominant in vibration and shaft displacement mixing signal in the no-load mode, while the frequency domain was wide without an obvious main frequency in pressure fluctuation mixing signal. Besides, the SSTκ-ω turbulence model was adopted to simulate the four quadrant characteristic curves of Baoquan model pump-turbine at three gate openings, and the relative error between simulation results and model test data was within ±6%, indicating that the simulation method in this paper is feasible and S-shaped characteristic of the pump-turbine can be simulated with CFD method.

关键词： pumped-storage power station no-load S-shaped characteristic pressure fluctuation SST κ-ω CFD

Azimuth resolution improvement for spaceborne SAR images with quasi-non-overlapped Doppler bandwidth

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Journal of Systems Engineering and Electronics 2014年第3期25卷 422-427页

作者： Yanyang liu Zhenfang li Zhiyong Suo jinwei li Zheng Bao National Laboratory of Radar Signal Processing Xidian University

The azimuth resolution improvement problem is solved via a coherent combination of synthetic aperture radar （SAR） ima-ges with the quasi-non-overlapped Doppler bandwidth. Prior to the spectra combination, SAR images should be coregistered, while phase biases induced by topography, atmospheric propagation delays and baseline measurement errors should be calibrated. However, the coregistration accuracy suffers from large Doppler decorrelation caused by the quasi-non-overlapped Doppler band-width. Furthermore, the method used to estimate phase biases from interferogram of azimuth prefiltered SAR image pairs wil fail when there is no overlapped spectrum. The fringe simulation and maximum sharpness optimization are adopted to deal with the problems. Accordingly, a novel algorithm to coherently synthesize SAR images is presented. The experiment with the Terra SAR X-band （TerraSAR-X） satel ite data validates the performance of the presented method.

关键词： synthetic aperture radar (SAR) azimuth resolution improvement maximum sharpness optimization fringe simulation.

Fluid properties and sources of Sixiangchang carbonate-associated mercury deposit, southwest China

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Acta Geochimica 2019年第5期38卷 670-682页

作者： Yuzhou Zhuo Yong Huang jinwei li Wei Gao Jinxiang li State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

Mercury mines in Guizhou province are the main base of mercury production and the most important resource base in *** San-Dan mercury belt in Guizhou province contains a series of important mercury ***,the source of metallogenic materials and the properties of metallogenic fluid of these mercury deposits have long been a controversial *** this study,we used cathode luminescence techniques to distinguish different stages of dolomite and calcite,laser ablation inductively coupled plasma mass spectrometry to analyze the trace elements,and stable isotope mass spectrometry techniques to analyze C-O isotopes compositions of dolomite and calcite in the Sixiangchang mercury deposit in San-Dan mercury *** also measured the sulfur isotope composition of *** study showed that dolomite can be divided into two stages,the lumpy dolomite associated with cinnabar in Dol 1 stage and dolomite vein in Dol 2 stage,which is associated with Cal 2 stage calcite *** the progress of mineralization,A1,As,Mo,Sb,and Sr elements were gradually enriched in the ore-forming *** rare earth element(REE)partition curve of Dol 1 stage dolomite showed a trend of light REE *** 2 stage calcite and Dol 2 stage dolomite exhibited a flat-type REE partition curve,and Dol 2 stage dolomite showed a strong negative anomaly for Eu.δ^13C of carbonate mineral variation ranges from-6.89 to-2.16‰,whileδ^18O variation ranges from 13.80 to 23.09‰,and theδ34S variation range of cinnabar is 16.51-24.28‰.Carbonate mineral trace elements and C-O isotopes compositions suggested that early ore-forming fluid was reduced,and late ore-forming fluid was *** oreforming fluid of the Sixiangchang mercury deposit is a mixture of deep crustal fluid and meteoric water in deep thermal circulation,and involved in the oxidation of organic *** cinnabarδ^34S results showed that sulfur mainly came from seawater sulfate with the participation of microbial reduction.

关键词： Trace elements Carbon and oxygen isotopes Sulfur isotope Calcite and dolomite Youjiang Basin

Synergistic effect of oregano essential oil fumigation combined with infrared heating on the inactivation of Aspergillus flavus

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Food Bioscience 2022年第6期50卷 1735-1745页

作者： Mengmeng Ji jinwei li liuping Fan State Key laboratory of Food Science&Technology Jiangnan University1800 Lihu AvenueWuxiJiangsu214122China School of Food Science and Technology Jiangnan University1800 Lihu AvenueWuxiJiangsu214122China Collaborat Innovat Ctr Food Safety&Qual Control Jiangnan University1800 Lihu AvenueWuxiJiangsu214122China

This study was aimed to evaluate the fungicidal effects of oregano essential oil (OEO) fumigation combined with intermediate-wave infrared (IWIR) heating on Aspergillus flavus (A. flavus ) in peanuts, and investigate the synergistic mechanism of the combined treatment (OEO-IWIR). Vitro experiments results indicated that OEO fumigation completely inhibited the A. flavus mycelium growth and aflatoxin production at a dose of 135 mg/L for 6 h. Meanwhile, the sterilization efficacy was assessed by inoculating peanuts with 6 log10 CFU/g A. flavus spores. OEO-IWIR exhibited synergistic effects and reached the 5-log reduction requirement by OEO fumigation at 135 mg/L for 6 h combined with IWIR heating at 65 °C for 1 h. Next, cultivability and spore viability tests of A. flavus were assayed. IWIR heating caused culturable sublethal spores, while the OEO-IWIR exhibited complete inactivation. Finally, the mechanism study confirmed that OEO-IWIR caused a higher degree of cell membrane permeabilization (from 17.0% to 65.6%), more significant alteration of cellular ultrastructure, and higher inhibition of ATPase activity than single treatments.

关键词： Aspergillus flavus Essential oil Fumigation Infrared heating Synergistic Inactivation

In-situ sulfur isotope and trace element of pyrite constraints on the formation and evolution of the Nibao Carlin-type gold deposit in SW China

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Acta Geochimica 2019年第4期38卷 555-575页

作者： Jinxiang li Chenghai Zhao Yong Huang Yuzhou Zhuo jinwei li State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China University of Chinese Academy of Sciences Beijing 100049China

The fault-controlled Nibao Carlin-type gold deposit,together with the strata-bound Shuiyindong deposit,comprise a significant amount of the disseminated gold deposits in southwestern Guizhou Province,*** main types and two sub-types of pyrite at the Nibao deposit(Py1a/Py1b,Py2,Py3,Py4,Py5)were distinguished based on detailed mineralogical ***1,Py2and Py3 are Au-poor,whereas Py4 and Py5 are Au-rich,corresponding to a sedimentary and hydrothermal origin,*** systematic in situ analyses of NanoSIMS sulfur isotopes,the framboid pyrite Py1a with negative δ^34S values(-53.3 to-14.9%)from the Nibao deposit were found to originate from bacterial sulfate reduction(BSR)processes in an open and sulfate-sufficient condition while the superheavy pyrite Py1b(73.7–114.8%)is probably due to the potential influence of closed-system Rayleigh fractionation or the lack of preservation of deepsea *** of Py2 and Py3 plot within the area of S isotope compositions from biogenic and abiogenic sulfate *** view of few coeval magmatic rocks in the mining district,the near zero δ^34S values of the Au-rich pyrites(Py4 and Py5)may discount the potential involvement of magmatic but metamorphic or sedimentary ***-ICP-MS and TEM work show that Au in ore-related pyrite is present as both nanoparticles and structurally ***-ICP-MS analyses show that the Au-rich pyrite also contains higher As,Cu,Sb,Tl and S than other types of pyrite,which inferred a distal manifestation of deep hydrothermal mineralization systems.

关键词： Nibao Carlin-type gold deposit Pyrite NanoSIMS LA-ICP-MS Sulfur isotopes

Microstructures and mechanical behaviors of CVI-based C/C composites containing h-BN powdered additives

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Journal of Materials Science & Technology 2019年第12期35卷 2824-2831页

作者： Peng Xiao Zhichao li Zeyan liu Zhuan li Bengu Zhang jinwei li Yang li National Key Laboratory of Science and Technology for National Defence on High-strength Structural Materials Central South UniversityChangsha 410083China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083China

Hexagonal boron nitride(h-BN) powders were introduced into carbon fiber preform by powder addition and subsequent combined with chemical vapor infiltration(CVI) for densification to prepare carbon fiber reinforced/carbon and boron nitride dual matrix composites(C/C-BN). Microstructures and mechanical properties of C/C composites with three different volume contents of h-BN powders were investigated in comparison to pure C/C composites. Results indicated that the introduction of h-BN powders into C/C composites significantly reduced the size of Py C and the anisotropy of thermal contraction in matrix,leading to a gradual disappearance of ring defects as the h-BN content increased. In addition, an enhanced interfacial bonding between fiber and matrix obtained due to higher-textured Py C and rougher fiber surface. Thereby, the flexural strengths and modulus of as-prepared composites decreased firstly and then increased, while the impact toughness presented a decreasing tendency as the content of BN powders increased. Furthermore, with the increasing of h-BN content, anisotropies of compressive properties were weakened, and the compressive strength of C/C-BN composites were always higher than that of pure C/C composit. However, when C/C composites modified by 13.5 vol% content of h-BN, excessive loose BN aggregates appeared in C/C-BN composites, leading to a relatively slight reduction of compressive strength.

关键词： C/C composites h-BN Pyrolytic carbon Interfacial bonding Mechanical properties

In vitro xanthine oxidase inhibitory properties of Flos Sophorae Immaturus and potential mechanisms

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Food Bioscience 2022年第3期47卷 964-974页

作者： Jun li Yuhong Gong jinwei li liuping Fan State Key Laboratory of Food Science & Technology Jiangnan University1800 Lihu AvenueWuxiJiangsu214122China School of Food Science and Technology Jiangnan University1800 Lihu AvenueWuxiJiangsu214122China Collaborat Innovat Ctr Food Safety & Qual Control Jiangnan University1800 Lihu AvenueWuxiJiangsu214122China Institute of Food Processing Technology Guizhou Academy of Agricultural SciencesGuiyang550006China

Flos Sophorae Immaturus (FSI) possessed potential xanthine oxidase (XO) inhibitory activity as a uric acid-lowing natural *** present work identified and quantified the free and bound polyphenols of FSI by *** determined the primary polyphenols with XO inhibitory effect and clarified their potential mechanisms by omission experiment,interaction assay,inhibition type,and fluorescence *** results revealed that nine polyphenols were detected in the free polyphenol extract and ten polyphenols were detected in the bound polyphenol ***,seven polyphenols were identified as XO inhibitors,including quercetin,kaempferol,isorhamnetin,rutin,hyperoside,protocatechuic acid,and quercitrin with the IC50 values of 0.03,0.11,0.07,5.62,11.48,22.13,and 367.82 mg/mL,but their inhibition stability was lower than 24 *** the content of quercetin (18.87 mg/g) was not the highest,it played a crucial role to the XO inhibitory effect of ***,kaempferol and isorhamnetin alone revealed the sub-additive effect with quercetin,while the combination of other polyphenols with quercetin generated the interference or antagonism ***,isorhamnetin,and kaempferol were mixed-type and competitive inhibitors,which significantly quenched the fluorescence intensity of ***,the binding processes of quercetin-XO,kaempferol-XO,and isorhamnetin-XO were spontaneous and endothermic,and the hydrophobic interaction was the key driving *** general,quercetin,kaempferol,and isorhamnetin in FSI can be used as potential XO inhibitors.

关键词： Polyphenols Flos sophorae immaturus Xanthine oxidase Interaction analysis Inhibition stability Fluorescence quenching

Improving the xanthine oxidase and adenosine deaminase inhibitory activities of Flos Sophorae Immaturus by ultrasound-assisted heating treatments

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Food Bioscience 2023年第1期51卷 420-429页

作者： Jun li Yuhong Gong jinwei li liuping Fan State Key Laboratory of Food Science&Technology Jiangnan University1800 Lihu AvenueWuxiJiangsu214122China School of Food Science and Technology Jiangnan University1800 Lihu AvenueWuxiJiangsu214122China Collaborat Innovat Ctr Food Safety&Qual Control Jiangnan University1800 Lihu AvenueWuxiJiangsu214122China Institute of Food Processing Technology Guizhou Academy of Agricultural SciencesGuiyang550006China

Flos Sophorae Immaturus(FSI)is consumed as a natural food rich in flavonoids and exhibits potential xanthine oxidase(XOD)and adenosine deaminase(ADA)inhibitory ***,ultrasound and heating treatments were applied to improve the XOD and ADA inhibitory effects of FSI,and the mechanisms were revealed by tracking the changes of *** showed that ultrasound(480 W,60 min)assisted heating treatments(180℃,60 min)significantly improved the XOD(from 40.97%to 83.47%)and ADA(6.64%-23.28%)inhibition ***,ultrasound and heat treatment caused significant variations in total polyphenols and flavonoid contents and altered the flavonoid composition of ***,rutin,kaempferol-3-o-rutinoside,and narcissoside of FSI converted to quercetin,kaempferol,and isorhamnetin during heating ***,the model experiment revealed that ultrasound treatment did not cause the conversion of flavones and just promoted the dissolution of FSI ***,quercetin,kaempferol,and isorhamnetin possessed better XOD and ADA inhibitory activities than rutin,kaempferol-3-o-rutinoside,and narcissoside at a concentration from 0.025 mg/mL to 1.0 mg/mL,implying de-glycosylation is a feasible approach for enhancing XOD and ADA *** present study provides a promising strategy for the processing of FSI.

关键词： Anti-xanthine oxidase activity Anti-adenosine deaminase activity Flos Sophorae Immaturus Flavones Ultrasound treatment Heating treatment

Effect of ultrasound-assisted freeze-dried on microstructure,bioactive substances,and antioxidant activity of Flos Sophorae Immaturus

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Food Bioscience 2022年第5期49卷 710-717页

作者： Yuhong Gong Jun li jinwei li liuping Fan li Wang State Key Laboratory of Food Science&Technology Jiangnan University1800 Lihu AvenueWuxiJiangsu214122China Department of life Science Lvliang UniversityLvliangShanxiChina Collaborat Innovat Ctr Food Safety&Qual Control Jiangnan University1800 Lihu AvenueWuxiJiangsu214122China School of Food Science and Technology Jiangnan University1800 Lihu AvenueWuxiJiangsu214122China

Flos Sophorae Immaturus(FSI)extract and its main active secondary metabolites have health benefits including antioxidant activity,but the drying process may negatively affect their quality and *** investigate the effect of ultrasound-assisted freeze-drying(UAFD)on FSI,the drying rate,colour,and microstructure samples were ***,the flavonoids and antioxidant activity of dried products were *** results showed that the drying rates were significantly enhanced with *** 600 W and 15 min,the drying time of UAFD was 40%shorter than that of freeze-drying(FD)*** micrographs showed that USAD created more porous structures that allowed water to migrate outward from inside the FSI *** conditions of 600 W ultrasonic power and 5 min ultrasonication time produced better antioxidant activity in dried products than in other *** highest characteristic properties were DPPH(75.51%),ABTS(95.14%),FRAP(83.05%),acceptable drying time(3 h),and low colour difference(1.09).Under these conditions,the contents of total flavonoids(298.34 mg/g),rutin(256.66 mg/g),quercetin(20.13 mg/g),kaempferol(19.64 mg/g),isorhamnetin(17.77 mg/g),and genistein(13.97 mg/g)were determined to be as *** results confirmed the obvious benefits of incorporating the ultrasonic effect into the FD method.

关键词： Flos Sophorae Immaturus Ultrasonic-assisted Freeze-drying Bioactive substances Antioxidant activity