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| 1 | Numerical and experimental investigation into hypersonic boundary layer transition induced by roughness elements显示文摘In this work, the Direct Numerical Simulation(DNS) and Oil-Film Interferometry(OFI)technique are used to investigate the hypersonic boundary layer transition induced by single and double roughness elements at Mach number 5. For single roughness, the DNS results showed that both horseshoe vortices and hairpin vortices caused by shear layer instability can affect the boundary layer instability. The generation of the near-wall unstable structure is the key point of boundary layer transition behind the roughness element. At the downstream of the roughness element, the interaction between horseshoe vortices and hairpin vortices will spread in the spanwise direction.For double roughness elements, the effect of the spacing between roughness elements on the transition is studied. It is found that the case of higher spacing between roughness elements is more effective for inducing transition than the lower one. The interaction between two adjacent roughness elements can suppress the evolution of horseshoe vortices in the downstream and trigger the instability of shear layer. Thus, the transition will be suppressed accordingly. | Hao DONG Shicheng LIU Xi GENG Song LIU Liming YANG Keming CHENG | 2019 | Chinese Journal of Aeronautics2019，32，3： | 6 |
| 2 | Effects of plant coverage on shrub fertile islands in the Upper Minjiang River Valley显示文摘The patchy distribution of vegetation in dry land results in well-documented 'fertile islands'. However, the response of shrub fertile islands to plant recovery and the underlying mechanisms, such as the linkage plant and soil properties, remain unknown.We sampled soils from areas with three different plant coverages(25%, 45%, and 75%) and three of their adjacent inter-plants to investigate soil physicochemical and microbial properties in the upper Minjiang River arid valley. The results showed that these factors were influenced by the persistence of plants that contrasted with the inter-plant interspaces. We found fertile islands in under-plant soil that were enhanced with increasing plant coverage, from 25% to 45% and 75%; however, there were no significant differences between 45% and 75% plant coverage apart from the soil clay content and the fungi to bacteria ratio. The soil microbial communities in under-plant soil were strongly influenced by the total soil carbon(TC), soil organic carbon(SOC),and available nitrogen(AN), whereas the microbial communities in inter-plant soil were primarily constrained by the AN and available phosphorous(AP). Moreover, the inter-plant soil properties, including gravimetric soil water content, pH, electrical conductivity(EC), and soil C:N ratio, were also strongly influenced by adjacent vegetation, which suggested that fertile islands may be beneficial for plant recovery in this region. | Laiye Qu Zhongbin Wang Yuanyuan Huang Yuxin Zhang Chengjun Song Keming Ma | 2018 | Science China(Life Sciences)2018，61，3： | 3 |
| 3 | Facile synthesis of hierarchical Na2Fe(SO4)2@rGO/C as high-voltage cathode for energy density-enhanced sodium-ion batteries显示文摘Fe-based sulfates are ideal cathode candidates for sodium-ion batteries(SIBs) owing to their high operating voltage and low cost but suffer from the nature of poor power performance. Herein, a hierarchical porous Na2Fe(SO4)2@reduced graphene oxide/carbon dot(Na2Fe(SO4)2@rGO/C) with low carbon content(4.12 wt%) was synthesized via a facile homogeneous strategy benefiting for engineering application,which delivers excellent sodium storage performance(high voltage plateau of 3.75 V, 85 m Ah g-1 and330 Wh kg-1 at 0.05 C;5805 W kg-1 at 10 C) and high Na+diffusion coefficient(1.19 × 10-12 cm2 s-1).Moreover, the midpoint voltage of assembled full cell could reach 3.0 V. The electron transfer and reaction kinetics are effectively boosted since the nanoscale Na2Fe(SO4)2 is supported by a robust crosslinked carbon matrix with rGO sheets and carbon dots. The slight rGO sheets sufficiently enhance the electron transfer like a current collecter and restrain the aggregation, as well as ensure smooth ion channels. Meanwhile, the carbon dots in the whole space connect with Na2Fe(SO4)2 and help rGO to promote the conductivity of the electrode. Ex-situ X-ray powder diffraction and X-ray photoelectron spectrometry analysis confirm the high reversibility of this sodiation/desodiation process. | Ge Yao Xixue Zhang Yongliang Yan Jiyu Zhang Keming Song Juan Shi Liwei Mi Jinyun Zheng Xiangming Feng Weihua Chen | 2020 | Journal of Energy Chemistry2020，29，11： | 3 |
| 4 | The study of methanol aromatization on transition metal modified ZSM-5 catalyst显示文摘In this article, transition metals of Cu, La and Zn were used as adjuvant to prepare modified HZSM-5 by impregnation method. The catalysts were characterized by XRD, BET, NH_3-TPD and Py-IR to reveal the microstructure and acid property. The catalysis performances of methanol aromatization of catalysts were investigated in a fixed-bed reactor. The results show that the strength and distribution of acid center of these catalysts are significantly influenced by the species of transition metal. There are more mediate strong Lewis acid center in Zn modified HZSM-5 catalyst and therefore exhibits higher selectivity to aromatic, benzene, toluene and xylenes in the MTA reaction.. | Keming Ji Jiayao Xun Ping Liu Qingwen Song Junhua Gao Kan Zhang Jingyuan Li | 2018 | Chinese Journal of Chemical Engineering2018，26，9： | 2 |
| 5 | Hydrocarbon Generation and Expulsion of the Upper Triassic T3x5Source Rocks in the Western Sichuan Depression: Assessment for Unconventional Natural Gas显示文摘Tight-sand gas in the Jurassic and shale gas within the fifth member of Xujiahe Formation(T3x5) in the Western Sichuan Basin(WSD) are currently regarded as the most prolific emerging unconventional gas plays in China. This study conducted a conventional evaluation of T3x5 source rocks in the WSD, and investigated their hydrocarbon generation and expulsion characteristics, including intensity, efficiency and amount. The results show that, the T3x5 source rocks are thick(generally >200 m), and have a high total organic content(TOC), ranging from 2.5 to 4.5 wt%. It is thus indivative of a great hydrocarbon generation potential when they underwent high thermal evolution(Ro>1.2%) in the area. In addition, an improved method of hydrocarbon generation potential is applied, indicating that the source rocks reached a hydrocarbon expulsion threshold with vitrinite reflectance(Ro) reaching 1.06%, and that the comprehensive hydrocarbon expulsion efficiency is about 60%. The amount of hydrocarbon generation and expulsion from T3x5 source rocks is 3.14×1010 t and 1.86×1010 t, respectively, with a residual amount of 1.28×1010 t within them. Continuous-type tight-sand gas is predicted to have developed in the Jurassic in the Chengdu Sag of the WSD because of the good source-reservoir configuration; the Jurassic sandstone reservoirs are tight, and the gas expelled from the T3x5 source rocks migrates for very short distances vertically and horizontally. The amount of gas accumulation in the Jurassic reservoirs derived from T3x5 source rocks is up to 9.3×108 t. Geological resources of shale gas are up to 1.05×1010 t. Small differences between the amounts calculated by the volumetric method and those obtained by hydrocarbon generation potential method may be due to other gas accumulations present within interbedded sands associated with gas shales. | GUO Yingchun SONG Yan PANG Xiongqi WANG Youwei YANG Keming LI Boyuan | 2015 | Acta Geologica Sinica(English Edition)2015，89，1： | 2 |
| 6 | Syn- thesis and Characterization of a Series of 2-Aminopyridine Nickel( Ⅱ ) Complexes and Their Catalytic Properties Toward Ethylene Polymerization 显示文摘 | Huang Zengfang Song Keming Liu Fengshou | 2008 | J Polym Sci Part A : Polymer Chem2008，46，5： | 1 |
| 7 | Characteristics of Se-Enriched Mycelia by Stropharia rugoso-annulata and its Antioxidant Activities in vivo显示文摘 | Zhen Song Le Jia Feng Xu Fanyun Meng Peng Deng Keming Fan Xiaonan Liu | 2009 | Biological Trace Element Research2009，，1： | 1 |
| 8 | Influenza virus vaccine expressing fusion and attachment protein epitopes of respiratory syncytial virus induces protective antibodies in BALB/c mice显示文摘 | Chengrong Bian Shuzhen Liu Na Liu Guangzhou Zhang Li Xing Yingwei Song Yueqiang Duan Hongjing Gu Ya Zhou Peirui Zhang Zhiwei Li Keming Zhang Zhaohai Wang Shaogeng Zhang Xiliang Wang Penghui Yang | 2014 | Antiviral Research2014，，： | 1 |
| 9 | Screening for and surveillance of high-risk patients with HBV-related chronic liver disease:Promoting the early detection of hepatocellular carcinoma in China显示文摘 | Peipei Song Xiaobin Feng Keming Zhang | 2013 | BioScience Trends2013，7，1： | 1 |
| 10 | Neutral nickel complexes chelating monoamidinate ligands: Syntheses, characterizations and catalytic properties toward ethylene oligomerization and norbomene polymerization显示文摘 | Liu Fengshou Gao Haiyang Song Keming | 2009 | Polyhedron2009，28，4： | 1 |
| 11 | Enhanced interfacial compatibility of FeS@N,S-C anode with ester-based electrolyte enables stable sodium-ion full cells显示文摘The development of sodium-ion full cells is seriously suppressed by the incompatibility between electrodes and electrolytes. Most representatively, high-voltage ester-based electrolytes required by the cathodes present poor interfacial compatibility with the anodes due to unstable solid electrode interphase(SEI). Herein, Fe S@N,S-C(spindle-like Fe S nanoparticles individually encapsulated in N,S-doped carbon) with excellent structural stability is synthesized as a potential sodium anode material. It exhibits exceptional interfacial stability in ester-based electrolyte(1 M NaClO_(4) in ethylene carbonate/propylene carbonate with 5% fluoroethylene carbonate) with long-cycling lifespan(294 days) in Na|Fe S@N,S-C coin cell and remarkable cyclability in pouch cell(capacity retention of 82.2% after 170 cycles at 0.2 A g^(-1)).DFT calculation reveals that N,S-doping on electrode surface could drive strong repulsion to solvated Na_(2) and preferential adsorption to ClO_(4)^(-) anion, guiding the anion-rich inner Helmholtz plane.Consequently, a robust SEI with rich inorganic species(NaCl and Na_(2)O) through the whole depth stabilizes the electrode–electrolyte interface and protects its integrity. This work brings new insight into the role of electrode’s surface properties in interfacial compatibility that can guide the design of more versatile electrodes for advanced rechargeable metal-ion batteries. | Jiyu Zhang Zhen Meng Dan Yang Keming Song Liwei Mi Yunpu Zhai Xinxin Guan Weihua Chen | 2022 | Journal of Energy Chemistry2022，31，5： | 0 |
| 12 | A Haze Feature Extraction and Pollution Level Identification Pre-Warning Algorithm显示文摘The prediction of particles less than 2.5 micrometers in diameter(PM2.5)in fog and haze has been paid more and more attention,but the prediction accuracy of the results is not ideal.Haze prediction algorithms based on traditional numerical and statistical prediction have poor effects on nonlinear data prediction of haze.In order to improve the effects of prediction,this paper proposes a haze feature extraction and pollution level identification pre-warning algorithm based on feature selection and integrated learning.Minimum Redundancy Maximum Relevance method is used to extract low-level features of haze,and deep confidence network is utilized to extract high-level features.eXtreme Gradient Boosting algorithm is adopted to fuse low-level and high-level features,as well as predict haze.Establish PM2.5 concentration pollution grade classification index,and grade the forecast data.The expert experience knowledge is utilized to assist the optimization of the pre-warning results.The experiment results show the presented algorithm can get better prediction effects than the results of Support Vector Machine(SVM)and Back Propagation(BP)widely used at present,the accuracy has greatly improved compared with SVM and BP. | Yongmei Zhang Jianzhe Ma Lei Hu Keming Yu Lihua Song Huini Chen | 2020 | Computers, Materials & Continua2020，，9： | 0 |
| 13 | A new acid pickling process for copper alloys显示文摘The cleaning process of removing oxides on the surface of copper alloy sheets was investigated systematically. Through optimizing, a perfect process was selected that is fit for removing oxides on the surface. By acid pickling, all kinds of copper oxides are removed completely, furthermore, no poisonous gases are given out and a smooth and clean surface of copper alloys is obtained. At present, the process is applied successfully in the copper-processing industry. | Xing Zou, Bo Song, Keming Fang, and Danniang Xu Metallurgy School, University of Science and Technology Beijing, Beijing 100083, China | 2002 | Journal of University of Science and Technology Beijing2002，9，2： | 0 |
| 14 | A Pyrazine-Based 2D Conductive Metal-Organic Framework for Efficient Lithium Storage显示文摘The merits of intrinsic electrical conductivity, high specific surface area, tunable chemical composition and tailor-made properties enable two-dimensional conductive metal-organic frameworks (2D c-MOFs) as promising next-generation electrode materials in the field of energy storage and conversion. Herein, we have designed and synthesized a novel pyrazine-based 2D c-MOF (TPQG-Cu-MOF) bearing extended π-conjugated structure and abundant redox active sites. Thanks to the excellent redox reversibility of pyrazine units and CuO2 units, as well as the insolubility of the rigid framework skeleton, TPQG-Cu-MOF as the cathode material of lithium-ion battery exhibits a reversible specific capacity (150.2 mAh·g–1 at 20 mAh·g–1), good cycling stability (capacity retention of 82.6% after 500 cycles at 1 A·g–1) and excellent rate performance. Comprehensive ex-situ spectroscopic studies revealed the reversible redox activity of pyrazine units and CuO2 units of TPQG-Cu-MOF during the Li+ insertion/extraction process. The deepening fundamental understanding of the structure-property relationship was proposed, which might pave the way for further development of efficient MOF-based energy storage devices. | Xiaoxiao Sun Xiaoli Yan Keming Song Ting Zhang Zongfan Yang Xi Su Weihua Chen Long Chen | 2023 | Chinese Journal of Chemistry2023，41，14： | 0 |
| 15 | Heath Assessment Method of EMU Trains in Level 3-5 Maintenance and Repair显示文摘An accurate and objective assessment of the health status of EMU trains is of great importance.In order to make sure the trains are functional,reliable,and endurable in their full life cycle(FLC),health assessment method for EMU trains after Level 3-5 maintenance and repair is studied.First,the element-selection principles and the assessment rules are defined;second,to present the complex topological relationship between the elements in assessment,a functional logical structure construction method is proposed;third,a health value calculation model is defined based on the element’s characteristics and their logical structures.The health variables of each element is calculated and fitted following the steps in the corresponding weight calculation methods.The assessment method is proved to be applicable and effective. | SONG Wenbin FU Shuangbo WU Keming | 2022 | Chinese Railways2022，，2： | 0 |
| 16 | Recent advances in photonic crystal with unique structural colors:A review显示文摘Inspired by special color-forming organisms in nature,photonic crystal materials with structural color function have been developed significantly with great potential applications for displays,sensors,anti-counterfeiting inks,etc.This review aims to summarize the functions,self-assembly modes,and ap-plications of different kinds of photonic crystal materials.The preparation methods and characteristics of monodisperse inorganic nanoparticles,polymer nanoparticles,inorganic/organic core-shell nanoparti-cles,and MOFs are discussed.Subsequently,we summarize the method of assembling colloidal parti-cles into photonic crystals,which is a template induction method,inkjet printing method,drop coating method,etc.Moreover,the potential application of structural color is presented including humidity re-sponse and magnetic field response in sensors fields,as well as the advantages and disadvantages of anti-counterfeiting,fabric coloring,displays,smart windows,and Biomedical Applications.Finally,we present the development prospects and key problems of photonic crystals. | Keming Zhu Changqing Fang Mengyuan Pu Jing Song Dong Wang Xing Zhou | 2023 | Journal of Materials Science & Technology2023，，10： | 0 |
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