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Chinese Journal of Chemical Engineering 2022年第6期35卷 161-172页

作者： Xiangjun li Shujun li Xiaoping Wang Muhammad Asif Nawaz Dianhua liu State Key Lab of Chemical Engineering East China University of Science and TechnologyShanghai 200237China

The synthesis of polyoxymethylene dimethyl ethers as an ideal diesel fuel additive is the current hot topic of modern petrochemical industry for their expedient properties in mitigating air pollutants emission during *** this work,a series of spherical sulfated zirconia catalysts were prepared by a one-pot hydrothermal method assisted with surfactant cetyltrimethylammonium bromide(CTAB).The prepared sulfated zirconia catalysts were used to catalyze PODEn synthesis from methanol and formaldehyde *** characterization(XRD,BET,SEM,TGA,NH_(3)-TPD,FTIR,and Py-IR)were employed to elaborate the structure–activity relationship of the studied catalytic *** results demonstrated that S/Zr molar ratio in precursor solution played an effective role on catalyst morphology and acidic properties,where the weak Brønsted acid sites and strong Lewis acid sites were favorable to the conversion of methanol and formation of long-chain PODEn,*** reaction parameters such as catalyst amount,molar ratio of FA/MeOH,reaction time,temperature and pressure were *** speculated reaction pathway for PODEn synthesis was proposed based on the synergy of Brønsted and Lewis acid sites,which suggested that Brønsted and Lewis acid sites might be advantageous to the activation of polyoxymethylene hemiformals[CH_(3)(OCH_(2))_(n)OH]and methylene glycol(HOCH_(2)OH),respectively.

关键词： Polyoxymethylene dimethyl ethers Spherical sulfated zirconia Methanol Formaldehyde Reaction pathway Synergistic effect

POINTWISE ESTIMATES OF SOLUTIONS FOR THE NONliNEAR VISCOUS WAVE EQUATION IN EVEN DIMENSIONS

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Acta Mathematica Scientia 2020年第4期40卷 1001-1019页

作者： Nianying li College of Science Binzhou UniversityBinzhou 256600China

In this article,we study the pointwise estimates of solutions to the nonlinear viscous wave equation in even dimensions(n≥4).We use the Green’s function *** approach is on the basis of the detailed analysis of the Green’s function of the linearized *** show that the decay rates of the solution for the same problem are different in even dimensions and odd *** is shown that the solution exhibits a generalized Huygens principle.

关键词： viscous wave equation pointwise estimate even dimensions

Standing Shocks in the Inner Slow Solar Wind

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Chinese Physics Letters 2011年第5期28卷 296-299页

作者： li Bo CHEN Yan-Jun li Xing Shandong Provincial Key Laboratory of Optical Astronomy&Solar-Terrestrial Environment School of Space Science and PhysicsShandong University at WeihaiWeihai 264209 State Key Laboratory of Space Weather Chinese Academy of SciencesBeijing 100190 Institute of Mathematics and Physics Aberystwyth UniversityAberystwyth SY233BZUK

We examine whether the flow tube along the edge of a coronal streamer supports standing shocks in the inner slow wind by solving an isothermal wind model in terms of the Lambert W *** is shown that solutions with standing shocks do exist and they exist in a broad area in the parameter space characterizing the wind temperature and flow *** particular,streamers with cusps located at a heliocentric distance(≥)3.2R⊙can readily support discontinuous slow winds with temperatures barely higher than 1 MK.

关键词： function flow readily

An improved attack on clock-controlled shift registers based on hardware implementation

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Science China(Information Sciences) 2013年第11期56卷 228-237页

作者： li Lei liU XiangHui WANG Zheng li FengHua Department of Applied Mathematics Zhengzhou Information Science and Technology Institute

We cryptanalyze a type of stream generator with three linear-feedback shift registers that are mutually clocked in a stop/go manner and have the property of sequences of state space *** guessing the clock-controlled sequence and employing a backtracking search,we propose an algorithm attack on the type of stream generator based on hardware *** particular,the time complexity of the algorithm attacking the encryption algorithm A5/1 is 243.869 clock *** our hardware architecture,we investigate the implementation of the algorithm on feld programmable gate array and application-specifc integrated circuit for an attack on A5/*** a result,we can retrieve the initial states of A5/1’s registers in 2 s on average without pre-computation if we have 64 known key-stream bits.

关键词： stop/go clocking A5/1 state space convergence SMITH special-purpose hardware

Effects of soil properties on accumulation characteristics of copper,manganese, zinc, and cadmium in Chinese turnip

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Plant Diversity 2019年第5期41卷 340-346页

作者： Boqun li Di Chen Yongping Yang Xiong li Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China Germplasm Bank of Wild Species Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China School of life Sciences Yunnan UniversityKunming 650091China

Clarifying the mechanisms of heavy metal(HM)accumulation and translocation from soil-root-leaf is crucial to coping with soil HM *** this study,we analysed copper(Cu),manganese(Mn),zinc(Zn)and cadmium(Cd)accumulation characteristics in Chinese turnips and the effect of soil physicochemical properties on both HM accumulation and *** results indicate that Chinese turnips absorb and translocate Mn,Zn,and Cd at much higher levels than they do *** we measured bioconcentration factors in Chinese turnips for different HMs in the same soil,we found Chinese turnip capacities for HM accumulation decrease from Zn>Mn>Cd>*** addition,the translocation factor for these HMs decreases from Mn>Cd>Zn>*** analysis indicates that soil p H and various soil components are either negatively or positively correlated with Mn,Zn,and Cd accumulation;also,soil properties are correlated with Mn translocation from root to *** findings may help evaluate HM accumulation and translocation mechanisms as well as artificially regulate HM uptake levels from soils to turnips.

关键词： Turnip Heavy metal Bioconcentration Phyto remediation Soil composition

Contrasting Thermoelectric Transport Behaviors of p-Type PbS Caused by Doping Alkali Metals (li and Na)

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Research 2020年第1期2020卷 666-676页

作者： Zhenghao Hou Dongyang Wang Jinfeng Wang Guangtao Wang Zhiwei Huang li-Dong Zhao School of Materials Science and Engineering Beihang UniversityBeijing 100191China School of Physics Henan Normal UniversityXinxiang 453007China

PbS is a latent substitute of PbTe thermoelectric materials,which is on account of its superiority in low cost and earth ***,the thermoelectric transport properties of p-type PbS by doping alkali metals(Na and li)are investigated and it is verified that li is a more effective dopant than *** introducing li,the electrical and thermal transport properties were optimized *** electrical transport properties were boosted remarkably via adjusting carrier concentration,and the maximum power factor(PF_(max))of~11.5μW/cmK^(2) and average power factor(PFave)~9.9μW/cmK^(2) between 423 and 730 K in Pb_(0.99)li_(0.01)S were achieved,which are much higher than those(~9.5 and~7.7μW/cmK^(2))of *** li and Na can weaken the lattice thermal conductivity *** the enlarged PF with suppressed total thermal conductivity,a maximum ZT~0.5 at 730 K and a large average ZT~0.4 at 423-730K were obtained in p-type Pb_(0.99)li_(0.01)S,which are higher than~0.4 and~0.3 in p-type Pb0.99Na0.01S,respectively.

关键词： dopant conductivity collective

The effect of secondary structures on the generation of characteristic events during the translocation of DNA hybrid through ?-hemolysin

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Science China Chemistry 2016年第1期59卷 135-141页

作者： Xingyong Wang Yuru li Ting li Lei liu Hai-Chen Wu School of Chemical Engineering University of Mining & TechnologyXuzhou Key Laboratory for Biomedical Effects of Nanomaterials & Nanosafety Institute of High Energy Physics Chinese Academy of Sciences

Nanopore has been developed to be a powerful,single-molecule analytical tool for sensing ions,small organic molecules and biomacromolecules such as proteins and ***,the identity of the analyte can be revealed by current amplitude changes and mean dwell time of the analyte binding *** some cases,generation of highly characteristic current events affords an alternative way of analyte determination with high confidence ***,we found that secondary structures in DNA/RNA hybrids might severely hinder the generation of signature events during their translocation through?-hemolysin *** this report,we propose a strategy to add a certain concentration of urea in the buffer solution for single channel recordings and validate that low concentration of urea can effectively denature the secondary structures in DNA hybrids and recover the generation of signature *** finding might be useful in other secondary structure-related nanopore sensing activities.

关键词： nanopore sensing DNA hybrid translocation signature event urea

Understanding micro-diffusion bonding from the fabrication of B_4C/Ni composites

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International Journal of Minerals,Metallurgy and Materials 2018年第3期25卷 365-374页

作者： Miao Wang Wen-xian Wang Hong-sheng Chen Yu-li li College of Materials Science and Engineering Taiyuan University of Technology Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of Education Taiyuan University of Technology

A Ni-B_4C macroscopic diffusion welding couple and a Ni-15 wt% B_4C composite fabricated by spark plasma sintering(SPS) were used to understand the micro-scale diffusion bonding between metals and ceramics. In the Ni-B_4C macroscopic diffusion welding couple a perfect diffusion welding joint was achieved. In the Ni-15 wt% B_4C sample, microstructure analyses demonstrated that loose structures occurred around the B_4C particles. Energy dispersive X-ray spectroscopy analyses revealed that during the SPS process, the process of diffusion bonding between Ni and B_4C particles can be divided into three stages. By employing a nano-indentation test, the room-temperature fracture toughness of the Ni matrix was found to be higher than that of the interface. The micro-diffusion bonding between Ni and B_4C particles is quite different from the Ni-B_4C reaction couple.

关键词： B4C/Ni composites spark plasma sintering micro-diffusion welding microstructure nano-mechanical property

Tidal currents in the coastal waters east of Hainan Island in winter

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Journal of Oceanology and limnology 2022年第2期40卷 438-455页

作者： Min li lingling XIE Xiaolong ZONG Junyi li Mingming li Tong YAN Ronglei HAN Laboratory for Coastal Ocean Variation and Disaster Prediction Guangdong Ocean UniversityZhanjiang 524088China Key Laboratory of Climate Resources and Environment in Continental Shelf Sea and Deep Sea of Department of Education of Guangdong ProvinceGuangdong Ocean UniversityZhanjiang 524088China Marine Resources Big Data Center of South China Sea Southern Marine Science and Engineering Guangdong Laboratory(Zhanjiang)Zhanjiang 524013China Institute of Marine Sciences Shantou UniversityShantou 515063China South China Sea Institute of Oceanology Chinese Academy of SciencesGuangzhou 510301China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Key Laboratory of Space Laser Communication and Detection Technology Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China

Using the 25-h continuing hydrographic observations at three successive stations in February 2012 and the mooring time series of current observations from January to March 2015,the tidal currents and tidal energy fluxes in the coastal waters east of Hainan Island in the northwestern South China Sea were *** diurnal and semidiurnal(using K_(1) and M_(2) as proxies,respectively)tidal currents and associated isopycnal undulations were derived with harmonic *** show that the velocities of the diurnal and semidiurnal tides derived from the 25-h observations are comparable to those from the mooring *** semi-major axes of the tidal ellipses were O(4-7 cm/s)for barotropic tides and O(2-4 cm/s)for baroclinic *** directions were in NE-SW at deeper stations to N-S at the shallowest station for the diurnal tide and from NW-SE to NE-SW for the semidiurnal *** the diurnal and semidiurnal isopycnal fl uctuations reached O(5 m),O(8 m),and O(10 m)at the cross-shelf stations(H03,H04,and H05)from 35 m,45 m,to 55 m,respectively,showing insignifi cant vertical variation,and the barotropic signals were *** baroclinic diurnal tide showed fi rst-mode structures at H03-05,as does the semidiurnal tide at *** semidiurnal tide at H04 and H05 exhibited higher-mode *** time series of both the alongshore and cross-shore components reveal the vertically propagation features of the baroclinic tidal phase and *** calculated horizontal energy fl uxes of the diurnal and semidiurnal internal tides decreased from O(0.1 W/m)at H05 to O(0.01 W/m)at H03,implying a propagation and dissipation of energy from off shore to inshore.

关键词： tidal current barotropic tide internal tide energy flux east of Hainan Island

Alkali ion-promoted palladium subnanoclusters stabilized on porous alumina nanosheets with enhanced catalytic activity for benzene oxidation

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Nano Research 2022年第7期15卷 5912-5921页

作者： Zhijun li Minghui Di Wei Wei Leipeng Leng Zhijun li Cheng He Qiang Tan Qian Xu J.Hugh Horton li li Junfa Zhu Joint International Research Laboratory of Advanced Chemical Catalytic Materials&Surface Science College of Chemistry and Chemical EngineeringNortheast Petroleum UniversityDaqing 163318China Key Laboratory of Functional Inorganic Materials Chemistry(Ministry of Education) School of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080China State Key Laboratory for Mechanical Behavior of Materials School of Material Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China Department of Chemistry Queen’s UniversityKingston K7L 3N6Canada College of Chemistry and Chemical Engineering Qiqihar UniversityQiqihar 161006China

Catalytic C−H bond activation is one of the backbones of the chemical *** metal subnanoclusters consisting of a few atoms have shown attractive properties for heterogeneous ***,the creation of such catalyst systems with high activity and excellent anti-sintering ability remains a grand ***,we report on alkali ion-promoted Pd subnanoclusters supported over defectiveγ-Al_(2)O_(3) nanosheets,which display exceptional catalytic activity for C−H bond activation in the benzene oxidation *** presence of Pd subnanoclusters is verified by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy,X-ray absorption spectroscopy,and X-ray photoelectron *** catalyst shows excellent catalytic activity,with a turnover frequency of 280 h^(−1) and yield of 98%,in benzene oxidation reaction to give phenol under mild ***,the introduction of alkali ion greatly retards the diffusion and migration of metal atoms when tested under high-temperature sintering *** functional theory(DFT)calculations reveal that the addition of alkali ion to Pd nanoclusters can significantly impact the catalyst’s structure and electronic properties,and eventually promote its activity and *** work sheds light on the facile and scalable synthesis of highly active and stable catalyst systems with alkali additives for industrially important reactions.

关键词： Pd subnanoclusters γ-Al_(2)O_(3)nanosheets heterogeneous catalysis benzene oxidation catalytic activity