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Effect of Cr on Steel Solidification Structure Under EMS

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Journal of Iron and Steel Research(International) 2012年第S1期19卷 394-399页

作者： CHEN Jin su zhi-jian Keiji Nakajima HE Ji-Cheng Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern University Division of Applied Process Metallurgy Department of Materials Science and Engineering Royal Institute of Technology(KTH)SE-10044 StockholmSweden

Solidification experiments of Cr steel under linear EMS were conducted to investigate the columnar-to-equiaxed transition(CET).The results are compared with those in carbon steel to clarify effect of Cr content and EMS.The conclusions are as follow:The criterion for dendrite fragmentation under linear EMS is obtained and verified by previous paper,then is considered valid for Cr steel.Investigation is carried out on the relation between the superficial velocity in the bulk flow and critical solid fraction at the time of dendrite fragmentation(CET occurrence).The critical solid fraction is smaller in high Cr case.As a result,the CET occurrence is more difficult in this case.

关键词： Cr steel secondary arm spacing dendrite fragmentation CET solid fraction

suppression of Effect of Uneven Velocity in submerged Entry Nozzle in Round Billet Continuous Casting Process Using Electromagnetic Swirling Flow

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Journal of Iron and Steel Research(International) 2012年第S2期19卷 905-908页

作者： LI De-wei su zhi-jian MARUKAWA Katsukiyo HE Ji-cheng Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern University Formerly sumitomo Metal Industries Ltd.

Sliding gate control system is widely employed in continuous casting process of steel to control flow rate of molten steel.As molten steel passes through a sliding gate,uneven flow develops.This will cause asymmetrical distribution of flow and temperature field in mold consequently,formation of vortex near the nozzle and entrapment of CC powder into the molten steel.etc,which have negative effect on process productivity and product quality.To suppress the uneven flow,electromagnetic swirling flow has been proposed to impose on the flow in submerged entry nozzle below the sliding gate.In this study the uneven flow developed by incompletely open sliding gate and the suppression of this uneven flow using electromagnetic swirling flow are numerically studied in round billet continuous casting of steel process.The improvement of the flow and temperature filed in the submerged entry nozzle and mold are investigated.It is found that:The uneven velocity in nozzle can be suppressed by electromagnetic swirling flow,and the flow and temperature field in mold be improved obviously;With the increase of electromagnetic swirling intensity,the effect of uneven flow can be almost completely suppressed.

关键词： continuous casting process sliding gate,uneven flow,electromagnetic swirling flow round billet

Graphene quantum dots for tumor optical diagnosis and treatment

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沈阳药科大学学报 2017年第9期34卷 805-816页

作者： ZHANG You-ying LI Quan WANG Wen-cheng ZHANG Qi-hao HUANG Ya-dong su zhi-jian XIANG Qi College of Pharmacy Jinan University College of Life Science and Technology Jinan University Institute of Biomedicine and Guangdong Provincial Key Laboratory of Bioengineering Medicine Jinan University

Graphene quantum dots(GQDs)are two-dimensional carbon nano-material with excellent physicochemical properties,including biocompatibility,high photoluminescence,water-solubility,hypotoxicity and so on.Owing to bigπ-conjugated structure and oxygen-containing functional groups,GQDs have the ability to absorb various chemical drugs viaπ-πstacking and electrostatic interaction.On the other hand,owning to photoluminescence,GQDs also have potential to serve as fluorescence probe for bioimaging,especially for optical diagnostics.In addition,GQDs have the ability to generate reactive oxygen species(ROS)including singlet oxygen upon photoexcitation.Therefore,GQDs are likely to be used for photodynamic therapy.This article aims to review the frontier researches about GQDs in the field of fluorescence probe,photodynamic therapy and anti-tumor drug delivery system.

关键词： graphene quantum dots drug delivery system tumor photodynamic therapy

Fundamental Study on Continuous Casting Process With Swirling Flow by Electromagnetic Force

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Journal of Iron and Steel Research(International) 2012年第S2期19卷 879-883页

作者： su zhi-jian LI De-wei CHEN-Jin MARUKAWA Katsukiyo HE Ji-cheng Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern University Formerly sumitomo Metal Industries Ltd.

Swirling flow in a submerged entry nozzle is effective on improving quality of casting block and casting speed in continuous casting of steel.A new method for swirling flow generation in the nozzle has been proposed by the authors,that is a rotating electromagnetic field is set up around a submerged entry nozzle(SEN)to induce swirling flow in it by Lorentz force.In this study,the magnetic field in molten steel in the submerged entry nozzle,the flow and temperature field in the SEN and mold in round,square billet and slab continuous casting process of steel are numerically studied.The model experiment of electromagnetic swirling continuous casting is also conducted with low melting point alloy.The commercial test for slab is undergoing.Results by numerical simulation and experiment show that the swirling flow by the optimum designed electromagnetic swirling generator can not only improve the distribution of flow and temperature in mold but also achieve the same effects generated by the swirling blade process. And,more effects on continuous casting process can be expected after this electromagnetic swirling process is optimized.

关键词： continuous casting process submerged entry nozzle swirling flow rotating magnetic field numerical simulation

Cosmological Constraints on Neutrino Masses in Light of JWST Red and Massive Candidate Galaxies

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Research in Astronomy and Astrophysics 2024年第4期24卷 7-12页

作者： jian-Qi Liu zhi-Qi Huang Yan su School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China CSST Science Center for the Guangdong-Hong Kong-Macao Greater Bay Area Zhuhai 519082China

The overabundance of the red and massive candidate galaxies observed by the James Webb Space Telescope(JWST)implies efficient structure formation or large star formation efficiency at high redshift z~10.In the scenario of a low or moderate star formation efficiency,because massive neutrinos tend to suppress the growth of structure of the universe,the JWST observation tightens the upper bound of the neutrino masses.Assuming A cold dark matter cosmology and a star formation efficiency∈[0.05,0.3](flat prior),we perform joint analyses of Planck+JWST and Planck+BAO+JWST,and obtain improved constraints∑m_(ν)sumptions,the inverted mass ordering,which implies ∑m_(ν)≥0.1 eV,is excluded by Planck+BAO+JWST at 92.7% confidence level.

关键词： (cosmology:)cosmological parameters galaxies:abundances galaxies:formation neutrinos

Comparison of main lactobacillus species between healthy women and women with bacterial vaginosis

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Chinese Medical Journal 2009年第22期122卷 2748-2751页

作者： YAN Dong-hui LU zhi su jian-rong The Center of Clinical Laboratory Beijing Friendship Hospital Capital Medical University Beijing 100050 China

Background The normal microbial flora of the vagina plays an important role in preventing genital and urinary tract infections in women. Thus an accurate understanding of the composition and ecology of the ecosystem is important to understanding the etiology of these diseases. This study aimed to compare the characteristics of main lactobacillus species between healthy women and women with bacterial vaginosis （BV） by quantitative culture and PCR methods. Main lactobacillus species include L. crispatus , L. gasseri, L. jensenii and L. iners.Methods A total of 150 Women attending Gynecology Outpatient Clinic of Beijing Friendship Hospital, were diagnosed as having BV because three or more of the following criteria were met （standard of Amsel＇s composite criteria）： homogeneous discharge, elevated vaginal pH （pH 〉4.5）, production of amines, and presence of ＂clue＂ cells. Those with less than three of the criteria were considered as healthy. Simultaneously, smears were made of vaginal fluid and Gram stained, then were assessed qualitatively as normal （grade Ⅰ）, intermediate （grade Ⅱ）, or consistent with BV （grade Ⅲ）. Gardnerella vaginalis were identified by using Vitek 2 Compact and PCR methods. Lactobacillus species were identified by PCR methods. Gardnerella vaginalis and lactobacilli colony counts were determined by calculating the most number of colonies of each species in the appropriate plates （colonies between 10 and 300）, corrected by the dilution of the sample in the plates, and multiplied by 10 （to account for plating 100 μl）, in order to get colony forming units per milliliter of vaginal secretion.Results BV was diagnosed in 31% （46/150） patients using the composite criteria, the remainder being regarded as healthy. The majority of patients with BV had a smear assessed as grade Ⅲ （91%, 42/46） and minority of them had a smear assessed as grade Ⅱ（9%, 4/46）. The majority of healthy women had a smear assessed as grade Ⅰ （64%, 67/104）. Smears assessed as grade Ⅱwere found （36%, 37/104） among patients diagnose

关键词： bacterial vaginosis vaginal smears lactobacillus Gardnerella vaginalis

Study of primordial deuterium abundance in Big Bang nucleosynthesis

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Nuclear Science and Techniques 2024年第3期35卷 208-215页

作者： zhi-Lin Shen jian-Jun He Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Institute of Radiation Technology Beijing Academy of Science and TechnologyBeijing 100875China

Big Bang nucleosynthesis(BBN)theory predicts the primordial abundances of the light elements^(2) H(referred to as deuterium,or D for short),^(3)He,^(4)He,and^(7) Li produced in the early universe.Among these,deuterium,the first nuclide produced by BBN,is a key primordial material for subsequent reactions.To date,the uncertainty in predicted deuterium abundance(D/H)remains larger than the observational precision.In this study,the Monte Carlo simulation code PRIMAT was used to investigate the sensitivity of 11 important BBN reactions to deuterium abundance.We found that the reaction rate uncertainties of the four reactions d(d,n)^(3)He,d(d,p)t,d(p,γ)^(3)He,and p(n,γ)d had the largest influence on the calculated D/H uncertainty.Currently,the calculated D/H uncertainty cannot reach observational precision even with the recent LUNA precise d(p,γ)^(3) He rate.From the nuclear physics aspect,there is still room to largely reduce the reaction-rate uncertainties;hence,further measurements of the important reactions involved in BBN are still necessary.A photodisintegration experiment will be conducted at the Shanghai Laser Electron Gamma Source Facility to precisely study the deuterium production reaction of p(n,γ)d.

关键词： Big Bang nucleosynthesis Abundance of deuterium Reaction cross section Reaction rate Monte Carlo method

Effect of Linear Electromagnetic Stirring on Behavior of Liquid Metal and Rate of Slag-Metal Interfacial Reactions

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Journal of Iron and Steel Research(International) 2010年第8期17卷 10-14页

作者： LI Yan-hua su zhi-jian HE Ji-cheng Key Laboratory of National Education Ministry for Electromagnetic Processing of Materials Northeastern University Shenyang 110004 Liaoning China

The internal flow,free surface shape,and level fluctuation of liquid metal exposed to linear electromagnetic stirring were measured and analyzed against the background of an actual metallurgical equipment with linear electromagnetic stirring system.The desulphurization process,with or without imposition of linear electromagnetic stirring,was also studied experimentally.The changes in sulfur content of hot metal with respect to time were obtained,and the volumetric mass transfer coefficients corresponding to different stirring currents were determined.The results showed that linear electromagnetic stirring can effectively promote internal flow,effectively increase the level fluctuation,and significantly improve the kinetic condition of liquid metal.The internal flow and level fluctuation of liquid metal increase in line with the increase in electromagnetic stirring intensity.The desulphurization experiments show that linear electromagnetic stirring can significantly promote the desulphurization process of hot metal,and that the technology has wide application potential in promoting various slag-metal reactions.

关键词： linear electromagnetic stirring Doppler ultrasound velocimetry internal flow level fluctuation interfacial reaction

Liquid-phase epitaxial layer by layer brushing fabrication of metalorganic frameworks films

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Nano Research 2024年第6期17卷 5698-5704页

作者： Li-Mei Chang Rui Zhai zhi-Zhou Ma jian-Dong Huang zhi-Gang Gu jian Zhang College of Chemistry Fuzhou UniversityFuzhou 350108China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China University of Chinese Academy of Sciences Beijing 100049China

Development of metal-organic framework(MOF)films is of great importance to expand their applications.Herein,we report a facile and universal method of liquid-phase epitaxial(LPE)layer by layer(LBL)brushing approach for fabricating MOF films on various substrates in a high-throughput fashion.This MOF films preparation method offers a great prospective to cost-effectively construct films with short preparation time and little reagent consumption.Moreover,this LBL brushing approach has been implemented successfully to assemble various MOF films,including HKUST-1,zeolitic imidazolate framework-8(ZIF-8),Cu(bdc),and Cu_(2)(L)_(2)P(L=bdc,ndc,and cam;P=dabco and bipy).Afterwards,the classic MOF HKUST-1 and ZIF-8 films were grown on sensor chip electrode and porous fiber support for good volatile organic compounds(VOCs)selective sensing and water purification applications.This study demonstrates that this LBL brushing preparation method can be employed to synthesize various MOF films with a variety of characteristics to realize their sensing and separation applications.

关键词： metal-organic framework porous materials layer by layer fabrication film