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Modulating the mean residence time difference of wide-size particles in a fluidized bed

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Chinese Journal of Chemical Engineering 2018年第2期26卷 238-244页

作者： Hu Zhao jun li Qingshan Zhu Hongzhong li State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

For non-catalytic gas-solid reaction, it is desirable to match the mean residence time （MRT） of particles and complete conversion time （tc） in a fluidized bed. In this study, the MRT differences （MRT ratios） between the coarse particles and the fine particles were investigated in a continuous fluidized bed with a side exit by varying the superficial gas velocity, feed composition and particle size ratio, The results show that the MRT ratio increases firstly and then decreases with increasing the gas velocity. By controlling the gas velocity and the feed composi tion of coarse particles, the MRT ratio can be modulated from 1.8 to 10.5 at the gas velocity of 1.0 m-s -1 for the binary mixture with the size ratio of 2.2. The MRT ratio can reach to - 12 at the gas velocity of 1.2 m. s for the particle size ratio of 3.3. The present study has endeavored to obtain fundamental data for an effective plant operation to meet the need of synchronously complete conversion of particles with different sizes during the film diffusion controlling reaction.

关键词： Fluidized bedMean residence timeWide size distributionBinarymixture

The blueberry(iron nodule)from the Shark Bay area, Western Australia and its implication to the genetic environments of iron nodules on Mars

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Science China Earth Sciences 2016年第3期59卷 640-650页

作者： li jun CHAN Lung Sang li Yi liang Department of Earth Sciences The University of Hong Kong

Fist-sized iron nodules, extensively found on the ground of Western Australia, were investigated by element analysis(XRF, ICP-MS and ICP-AES), electron microscopes, X-ray diffraction and M?ssbauser spectroscopy. Loosely-packed pisoidic structures of a few to >10 mm in size were observed in the cross-section of nodules. Chemically, the nodules are majorly made of O, Si, Fe and Al, and share similar REE pattern with the loess sourced Greatford concretions from New Zealand. Angular quartz particles, nano-sized goethite and hematite are found to be the major mineral phases. Other minerals, such as detrital zircon, barite and Ce-containing particles can also be observed but of very low abundance. No detectable carbonate or amorphous silica implies that these nodules have experienced little underground fluid alteration. The quartz particles showing particularly three sections of fractal size-distributions, together with their extensive broken features and conchoidal fractures, strongly suggest in situ fragmentation of the host rock with minimum later dynamic sorting. These observations indicate the genetic environment of those nodules is always close to the surface of the tectonically stable ground since their formation. Because of the similarity of climatic and geological features, the genesis and preservation environment of these nodules in Western Australia may provide clues on the formation of Martian iron concretions.

关键词： Iron nodules Western Australia Fractal dimensions In situ fragmentation Mars

NUMERICAL STUDY OF 3D EXPLOSION BUBBLES ADJACENT TO STRUCTURES

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Journal of Hydrodynamics 2002年第4期14卷 66-72页

作者： li, Wan-Ping li, liang-jun Dept. of Mech. Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

The bejavior of a bubble near a rigid structure was considered by using the local surface fitting method and the jet prediction method. The convergence difficulty caused by the abnormality of the elements was overcome. The flow was numerically simulated by using the boundary-integral method on the assumption that the water was inviscid and incompressible, and the bubble gas obeyed the isentropic rule. The evolution of the bubble was investigated by means of the mixed Euler-Lagrange method, and the Runge-Kutta method. The important behavior of the bubble, such as migration and jetting, was analyzed in several examples. The solution of one period of the explosion bubble was obtained.

关键词： Bubbles (in fluids) Shock waves Structures (built objects)

Recent advances in CRISPR/Cas9 and applications for wheat functional genomics and breeding

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aBIOTECH 2021年第4期2卷 375-385页

作者： jun li Yan li ligeng Ma College of life Sciences State Key Laboratory of North China Crop Improvement and RegulationHebei Agricultural UniversityBaoding 071001HebeiChina College of life Sciences Beiing Key Laboratory of Plant Gene Resources and Biotechnology for Carbon Reduction and Environmental ImprovementCapital Normal UniversityBeijing 100048China

Common wheat(Triticum aestivum L.)is one of the three major food crops in the world;thus,wheat breeding programs are important for world food *** the genes that control important agronomic traits and finding new ways to alter them are necessary to improve wheat *** genomics and breeding in polyploid wheat has been greatly accelerated by the advent of several powerful tools,especially CRISPR/Cas9 genome editing technology,which allows multiplex genome ***,we describe the development of CRISPR/Cas9,which has revo-lutionized the field of genome *** addition,we emphasize technological breakthroughs(*** editing and prime editing)based on CRISPR/*** also summarize recent applications and advances in the functional annotation and breeding of wheat,and we introduce the production of CRISPR-edited DNA-free *** with other achievements,CRISPR and CRISPR-based genome editing will speed progress in wheat biology and promote sustainable agriculture.

关键词： Wheat CRISPR/Cas9 Genome editing Functional genomics Breeding

Pascal Realization by Comb-Spectral-Interferometry Based Refractometer

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Chinese Physics Letters 2018年第10期35卷 85-88页

作者： li-jun Yang Yan li State Key Laboratory of Precision Measurement Technology & Instruments Department of Precision InstrumentsTsinghua University

To break through the limitations of existing pressure standards, which rely on the gravity and toxic mercury,the national metrological institutes prefer a quantum-based pressure standard. Combining the ideal gas law with helium refractivity measurement, we demonstrate a scheme for the realization of the pressure unit. The refractometer is based on a spectral interferometry with an optical frequency comb and a double-spaced vacuum cell. Through fast Fourier transform of the spectral interferograms of the two beams propagating inside and outside the vacuum cell, the helium refractivity can be obtained with a combined standard uncertainty u（n） of2.9 × 10-9. Moreover, the final u（n） is -8.7 × 10-6 in a measurement range of several megapascals（MPa）. Our apparatus is compact, fast（15 ms for one single measurement） and easy to handle. Furthermore, the measurement uncertainty will be improved to-1 × 10-9 or lower if a VIPA-based spectrometer is used. The value of u（p） will thus increase to 3 × 10-6 or better in several MPa.

关键词： Pascal Realization by Comb-Spectral-Interferometry Based Refractometer

Accuracy of intraocular lens power calculation formulae after laser refractive surgery in myopic eyes:a meta-analysis

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Eye and Vision 2020年第3期7卷 356-365页

作者： Hongyu li li Nan jun li Hui Song Clinical College of Ophthalmology Tianjin Medical UniversityTianjinChina Tianjin Eye Institute Tianjin Key Lab of Ophthalmology and Visual ScienceTianjin Eye HospitalNo.4 Gansu RoadHe-ping DistrictTianjin 300020China

Background:To compare the accuracy of intraocular lens power calculation formulae after laser refractive surgery in myopic ***:We searched the databases on PubMed,EMBASE,Web of Science and the Cochrane library to select relevant studies published between Jan 1st,2009 and Aug 11th,*** outcomes were the percentages of refractive prediction error within±0.5 D and±1.0 ***:The final meta-analysis included 16 studies using seven common methods(ASCRS average,Barrett True-K no history,Double-K SRK/T,Haigis-L,OCT formula,Shammas-PL,and Wang-Koch-Maloney).ASCRS average yielded significantly higher percentage of refractive prediction error within±0.5 D than Haigis-L,Shammas-PL and WangKoch-Maloney(P=0.009,0.01,0.008,respectively).Barrett True-K no history also yielded significantly higher percentage of refractive prediction error within±0.5 D than Shammas-PL and Wang-Koch-Maloney(P=0.01,P<0.0001,respectively),and a similar result was found when comparing OCT formula with Haigis-L and Shammas-PL(P=0.03,P=0.01,respectively).Conclusion:The ASCRS average or Barrett True-K no history should be used to calculate the intraocular lens power in eyes after myopic laser refractive *** OCT formula if available,can also be a good alternative choice.

关键词： Myopic Laser Refractive IOL power calculation Meta-analysis

Spatiotemporal pattern formation in parametrically driven two-dimensional Bose–Einstein condensates

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Communications in Theoretical Physics 2024年第12期76卷 150-156页

作者： jun Wan Wen Wen Hui-jun li College of Mechanics and Engineering Science Hohai University Institute of Nonlinear Physics and Department of Physics Zhejiang Normal University Zhejiang Institute of Photoelectronics and Zhejiang Institute for Advanced light Source Zhejiang Normal University

We investigate spatiotemporal periodic patterns in harmonically trapped Bose–Einstein condensates(BECs) driven by a periodic modulation of the interaction. Resonant with the breathing mode, we show the emergence of a square lattice pattern containing two orthonormal stripes. We study the time evolutions of the lattice patterns for different driving strengths and dissipations. We find that its spatial periodicity and temporal oscillating frequency match the Bogoliubov dispersion, which is the intrinsic property of the system and relevant to the parametric amplification of elementary excitations. In the circumstances of strong driving strength and low dissipation, we further observe the triad interaction and the resulting superlattice state, which are well explained by the nonlinear amplitude equation for superimposed stripes. These results shed light on unexplored nonlinear spatiotemporal dynamics of two-dimensional patterns in harmonically trapped BECs that can pave the way for engineering exotic patterns by state-of-the-art experiments.

关键词： spatio-temporal periodicity square lattice pattern triad interaction

Low-protein diet supplemented with 1% L-glutamine improves growth performance, serum biochemistry, redox status, plasma amino acids, and alters fecal microbiota in weaned piglets

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Animal Nutrition 2024年第2期17卷 144-154页

作者： jun li jun Bai Ying Yang Zhenlong Wu State Key Laboratory of Animal Nutrition and Feeding Department of Companion Animal Science China Agricultural University

Glutamine, one of the most abundant amino acids in the body, has been shown to exert various beneficial effects in pigs. However, knowledge regarding the role of dietary glutamine in low-protein diet-fed piglets remains scarce. The present study aimed to investigate the effects of different levels of L-glutamine on growth performance, serum biochemistry parameters, redox status, amino acids, and fecal microbiota in low-protein diet-fed piglets. A total of 128 healthy crossbred piglets(Landrace × Yorkshire)were randomly allocated into 4 groups of 4 replicate pens, with 8 piglets per pen. Piglets in the 4 groups were fed with corn and soybean meal-based low-protein diets(crude protein level, 17%) that contained0%, 1%, 2%, and 3% L-glutamine, respectively, for 28 d. Pigs administered 1% L-glutamine had greater body weight on d 28 and average daily gain(ADG, P line content(P < 0.05). Additionally, 1% Lglutamine upregulated the abundance of p＿75＿a5, Clostridium, Lactobacillus, Prevotellaceae＿Prevotella,and Gemmiger in the stool of piglets on d 14, with the Streptococcus lev

关键词： Glutamine Low protein diet Pig Redox status Amino acid Microbiota

A two-stage reduction process for the production of high-purity ultrafine Ni particles in a micro-fluidized bed reactor

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Particuology 2015年第2期13卷 27-34页

作者： jun li Xinwei liu li Zhou Qingshan Zhu Hongzhong li State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of Sciences

A novel two-stage reduction process for synthesis of ultrafine nickel powder with a high purity and low density in a fluidized bed reactor has been developed in this work. The raw ultraflne NiO particles are first pre-reduced using hydrogen at lower temperatures （340-400 ℃）, followed by further reduction at higher temperatures （500-600℃）. The self-agglomeration of Ni particles formed during low-temperature reduction decreases the sintering activity of the newly formed ultrafine Ni particles, leading to good fluidization quality, even for the subsequent high-temperature reduction process. The agglomerated Ni particles have a high Ni content （above 99wt%）, a low density （0.78g/cm^3） and a uniform particle size （approximately 100 μm）. A concept design for a novel two-stage fluidized bed reactor process used to produce high-purity Ni powder was also proposed. This approach may be extended to the synthesis of other ultrafine/nanosized metals or metal oxides through a fluidization method.

关键词： Ultrafine Ni powder Production Fluidized bed reactor Two-stage reduction