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Experiments and model for the surface tension of carbonated monoethanolamine aqueous solutions

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Science China Chemistry 2012年第7期55卷 1467-1473页

作者： FU Dong XU YiFei WANG LanFen chen lihong School of Environmental Science and Engineering North China Electric Power UniversityBaoding 071003China

The surface tension of carbonated monoethanolamine aqueous solutions from 293.15 to 323.15 K was measured by using an automatic surface tension-meter.A model applicable for the surface tension of MEA-CO2-water mixtures was proposed and the calculated results agreed well with the *** influences of temperature,MEA concentration and CO2 loading were demonstrated on the basis of experiments and calculations.

关键词： MEA aqueous solution CO2 loading surface tension

Potential effect of sedimentary iron-phosphorus accumulation on frequent algal bloom in the Pearl River Estuary

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Science China Earth Sciences 2007年第3期50卷 453-461页

作者： WENG HuanXin SUN XiangWei chen JingFeng chen JianFang chen lihong chen XiangHua QIN YaChao Institute of Environment&Biogeochemistry Zhejiang UniversityHangzhou 310027China Second Institute of Oceanography State Oceanic AdministrationHangzhou 310027China

Based on laboratory culture of harmful alga on iron and phosphorus uptake, and the study of accu-mulation of iron-phosphorus in cores and release of iron and phosphorus from surficial sediments collected in the Pearl River Estuary, the reasons of the high frequency of phytoplankton bloom therein are discussed. The results show that Fe starvation can make algal growth rate slow down and the peak of cell number decrease. Fe and P contents in algal cell bear a significant correlation and the molar ratio of P:Fe is ~356:1, suggesting that algal uptake of Fe and P is synergistic. Total Fe and total P in sediments are positively correlated and Fe-P is the main species of inorganic sedimentary P. Through continuous leaching with agitation, 34.26%―80.21% of exchangeable P and 4.04%―22.52% of ex-changeable Fe are released from surficial sediments, implying that the accumulation of Fe-P in sedi-ments is available for providing nutrients (P and essential Fe) for the demand of phytoplankton bloom. These factors might be responsible for a higher frequency of red tides than other marine regions.

关键词： sedimentary Fe-P iron limitation harmful algal bloom Pearl River Estuary

Quantitative deterministic versus probability analyses based on a safety margin criterion

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Science China(Technological Sciences) 2014年第10期57卷 1988-2000页

作者： chen ZuYu chen lihong XU Jiacheng SUN Ping WU Chao WANG YuJie State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin Department of Geotechnical Engineering China Institute of Water Resources and Hydropower Research School of Civil Engineering Beijing Jiaotong University China International Engineering Consulting Corporation

This paper proposes a new criterion called the ratio of safety margin(RSM)for use in the areas of the global factor of safety,reliability and limit states analyses with reference to their respective allowable *** equation for calculating RSM based on the reliability index is *** for proving the applicability of this criterion include a theoretical demonstration in a simple one-variable case;an investigation on a test problem involving two random variables,followed by a slope stability study on a 156 m high embankment dam and an illustrative example presented in a EuroCode 7 *** of the ratios of safety margin in the three areas provides a quantitative way to accommodate the analytical results within the same theoretical framework and makes the outcomes mutually comparable and supportive,which is much more enlightening than that would be the case by considering only one of *** RSMs for reliability and limit states methods has also helped solve the key issue concerning the uniqueness of the partial factors calibrated from a particular‘target case’.

关键词： factor of safety reliability index partial factor ratio of safety margin embankment dam reliability analysis

Tuning Order-Disorder Phase Transition through Regulating the Substituent Group of Anion

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Chinese Journal of Chemistry 2017年第6期35卷 957-963页

作者： Dong Li lihong chen Haixia Zhao Lasheng Long Lansun Zheng State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry College of Chemistry and Chemieal Engineering Xiamen University Xiamen Fujian 361005 China

The structural phase transition compound {[（CH3）2CHCH2]2NH2}·[CF3COO] （1） has been synthesized based on the diisobutylamine and trifluoroacetic acid. The DSC data reveal that 1 undergoes a phase transition at 277 K （Tc）. When one chlorine atom replaces one fluorine atom on trifluoroacetate anion, three order-disorder phase transitions at 251 K （Ti）, 282 K （T2） and 290 K could be achieved owing to a stepwise release of rotation motions of the anion and cation in {[（CH3）2CHCH2]2NH2}·[CF2C[COO] （2）. Based on the variable temperature crystal structures, the phase transition in compound 1 is triggered by the rotation of three fluorine atoms on the trifluoroacetate anion synchronized with the motions of the methyl groups on the diisobutylammonium cation. However, in compound 2, the phase transitions can be realized by a sequence of motions of both the anion and cation. Besides, the dielectric- temperature dependences were investigated in order to prove this regulation process. All of this investigation will be beneficial to design and synthesis of the novel phase transition materials and molecular dielectric materials on pur- pose.

关键词： phase transition dielectric materials order-disorder phase transition structural phase transition

Spatial resolved temperature measurement based on absorption spectroscopy using a single tunable diode laser

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Acta Mechanica Sinica 2010年第1期26卷 147-149页

作者： Xilong Yu Fei Li lihong chen Xinyu Zhang Key Laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences100190 Beijing China

A novel method based on wavelength-multiplexed line-of-sight absorption and profile fitting for nonuniform flow field measurement is reported. A wavelength scanning combing laser temperature and current modulation WMS scheme is used to implement the wavelength-multi- plexed-profile fitting method. Second harmonic （2f） signal of eight H20 transitions features near 7,170 cm^-1 are measured in one period using a single tunable diode laser. Spatial resolved temperature distribution upon a CH4/air premixed flat flame burner is obtained. The result validates the feasibility of strategy for non-uniform flow field diagnostics by means of WMS-2f TDLAS.

关键词： WMS-2fTDLAS - Profile fitting Spatial resolved - Temperature measurement

A modified soil water content measurement technique using actively heated fiber optic sensor

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第3期12卷 608-619页

作者： Meng Wang Xu Li lihong chen Senquan Hou Guiyan Wu Zhilin Deng Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijingChina Qinghai Research and Observation Base Key Laboratory of Highway Construction&Maintenance Technology in Permafrost RegionsMinistry of TransportXiningQinghaiChina

Soil water content measurement is critical in practical *** actively heated fiber Bragg grating optic sensor(FBGS)has great potential of multi-point measurement for soil water content measurement in *** this study,the effect of heating time on the measurement accuracy is discussed,and modifications are made for actively heated fiber optic(AHFO)*** results demonstrate that if an integration data analysis method is used,the accuracy and reliability of soil water content measurement with AHFO sensors will be *** a short fiber length and a short-term heating pattern are effective and can help to reduce soil *** the proposed integration method,a short heating time is guaranteed for measuring the soil water *** improvements will reduce the thermal disturbance to soil sample and improve the reliability of measurement.

关键词： Fiber bragg grating Carbon fiber heated sensor Unsaturated soil Field monitoring Soil water content measurement

B-Valued Dyadic Derivative

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Wuhan University Journal of Natural Sciences 2007年第6期12卷 961-964页

作者： ZHANG Chuanzhou chen lihong,LIU Peide School of Mathematics and Statistics Wuhan UniversityWuhan 430072 Hubei China

The principles of the new maximal operator H＊ we defined are discussed. We prove that it is bounded from martingale Hardy-Lorentz L^Xp.q[0,1） to the Lorentz L^Xp.q[0,1） for 1/2〈 p〈∞, 0〈~ q ≤ ∞, where X is any Banach space. When the Banach space X has the RN property, the sequence dnHnf converges to f a.e. Meanwhile the convergence in L^Xp norm for 1≤p〈∞ is a consequence of that the family functions K （n∈N） is an approximate identity.

关键词： martingale Hardy space dyadic derivative dyadic integral

Synergistic effect of V and Fe in Ni/Fe/V ternary layered double hydroxides for efficient and durable oxygen evolution reaction

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Frontiers of Chemical Science and Engineering 2023年第1期17卷 102-115页

作者： lihong chen Ruxin Deng Shaoshi Guo Zihuan Yu Huiqin Yao Zhenglong Wu Keren Shi Huifeng Li Shulan Ma Beijing Key Laboratory of Energy Conversion and Storage Materials College of ChemistryBeijing Normal UniversityBeijing 100875China School of Basic Medical Sciences Ningxia Medical UniversityYinchuan 750004China Analytical and Testing Center Beijing Normal UniversityBeijing 100875China State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering Ningxia UniversityYinchuan 750021China

High-performance and stable electrocatalysts are vital for the oxygen evolution reaction(OER).Herein,via a one-pot hydrothermal method,Ni/Fe/V ternary layered double hydroxides(NiFeV-LDH)derived from Ni foam are fabricated to work as highly active and durable electrocatalysts for *** changing the feeding ratio of Fe and V salts,the prepared ternary hydroxides were *** an Fe:V ratio of 0.5:0.5,NiFeV-LDH exhibits outstanding OER activity superior to that of the binary hydroxides,requiring overpotentials of 269 and 274 mV at 50 mA·cm^(−2)in the linear sweep voltammetry and sampled current voltammetry measurements,***,NiFeV-LDH shows extraordinary long-term stability(≥75 h)at an extremely high current density of 200 mA·cm^(−2).In contrast,the binary hydroxides present quick decay at 200 mA·cm^(−2)or even reduced current densities(150 and 100 mA·cm^(−2)).The outstanding OER performance of NiFeV-LDH benefits from the synergistic effect of V and Fe while doping the third metal into bimetallic hydroxide layers:(a)Fe plays a crucial role as the active site;(b)electron-withdrawing V stabilizes the high valence state of Fe,thus accelerating the OER process;(c)V further offers great stabilization for the formed intermediate of FeOOH,thus achieving superior durability.

关键词： oxygen evolution reaction electrocatalysts ternary layered double hydroxides long-term stability

Numerical investigation on flow and convective heat transfer of aviation kerosene at supercritical conditions

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Science China(Technological Sciences) 2013年第4期56卷 416-422页

作者： DANG GuoXin ZHONG FengQuan chen lihong CHANG XinYu State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of Sciences

In this paper,characteristics of flow and convective heat transfer of China RP-3 kerosene in straight circular pipe were numerically ***-Stokes equations were solved using RNG k-turbulence model with low Reynolds number *** thermophysical and transport properties of the China RP-3 kerosene were calculated with a 10-species surrogate and the extended corresponding state method(ECS) combined with Benedict-Webb-Rubin *** independence of grids was first studied and the numerical results were then compared with experimental data for *** flow conditions given in the paper,the results show that deterioration of convective heat transfer occurs when the wall temperature is slightly higher than the pseudo-critical temperature of kerosene for cases with wall heat flux of 1.2 and 0.8 MW/m *** degree of the heat transfer deterioration is weakened as the heat flux *** deterioration,however,does not happen when the heat flux on the pipe wall is reduced to 0.5 MW/m *** on the analysis of the near-wall turbulent properties,it is found that the heat transfer deterioration and then the enhancement are attributed partly to the change in the turbulent kinetic energy in the vicinity of pipe *** conventional heat transfer relations such as Sieder-Tate and Gnielinski formulas can be used for the estimation of kerosene heat convection under subcritical conditions,but they are not capable of predicting the phenomenon of heat transfer *** modified Bae-Kim formula can describe the heat transfer *** addition,the frictional drag would increase dramatically when the fuel transforms to the supercritical state.

关键词： aviation kerosene supercritical convective heat transfer numerical study

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