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Computational Research on Rotating Channel by a Modified Anisotropic Turbulence Model

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Journal of Thermal Science 2011年第5期20卷 385-393页

作者： Jianqin zhu zhi Tao Chaoqun Nie Institute of Engineering Thermophysics Chinese Academy of Science Beijing 100190 China National Key Lab. on Aero-Engines School of Jet Propulsion Beihang University Beijing 100191.China

Based on the simplified format of the Reynolds stress equations, a fire-new rotational-modification method for the anisotropic turbulence model has been presented. A three-dimensional Navier-Stokes code with this new rotational modified k-ω turbulence models （β=0.1 and β=1） and the standard k-ω turbulence model have been used for the prediction of flow and heat transfer characteristics in a rotating smooth square channel. The Reynolds number Re based on the inlet velocity of the cooling air and hydraulic diameter is 6000 .The rotating speed are 300, 600, 900, 1200rpm respectively. The calculations results of using three turbulence models have been compared with the experimental data. The research results show that （1） the rotational modification coefficient Rf13 used in the new anisotropic k-ω model would increased/decreased the predictions of heat transfer on the trailing surface/leading surface compared to the standard k-ω model. And this tendency would be increased with the increased ft. （2） The simulation performance of the standard k-ω model was well on the leading surface. However, on the trailing surface it under-predicted the heat transfer at high rotating speed. （3） The calculation results of the new anisotropic k-ω model with β=0.1 proposed by the present paper agreed well with experimental data, both on the leading and trailing surfaces. Besides, compared to 1, 0.1 is a more appropriate magnitude of βat conditions in the present paper.

关键词： anisotropy turbulence model rotation heat transfer

Organic topological insulators(OTI): a dream coming true?

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National Science Review 2020年第6期7卷 996-997页

作者： Danfeng zhi Chong-an Di Daoben zhu Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic SolidsInstitute of Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

Topological insulators (TIs) are a class of materials with insulating bulk states but exotic metallic states on their surfaces [1]. Benefiting from topological boundary states, TIs have become one of the most important topics in condensed materials, not only because they offer a unique perspective for revealing the origin of various quantum phases, but also because of their potential applications in spintronics and quantum com-

关键词： Electric insulators

NUMERICAL INVESTIGATION OF CAVITATION PERFORMANCE OF SHIP PROPELLERS

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Journal of Hydrodynamics 2012年第3期24卷 347-353页

作者： zhu zhi-feng FANG Shi-liang Key Laboratory of Underwater Acoustic Signal Processing Ministry of Education Southeast University Nanjing 210096 China School of Electrical Engineering and Information Anhui University of Technology Maanshan 243002 China Key Laboratory of Underwater Acoustic Signal Processing Ministry of Education Southeast University Nanjing 210096 China

The cavitation performance of propellers is studied based on viscous multiphase flow theories. With a hybrid grid based on Navier-Stokes （N-S） and bubble dynamics equations, some recent validation results are presented in this paper in the predictions of the thrust, the torque and the vapor volume fraction on the back side of propeller blade for a uniform inflow. The numerical predictions of the hydrodynamic performance and the sheet cavitation under several operating conditions for two propellers agree with the corresponding measured data in general. The thrust and the torque are plotted with respect to the advance rate and the cavitation number. The cavitation performance breakdown is closely related to the strong sheet cavitation around propellers. The models with parameters modified are shown to predict the propeller cavitation well.

关键词： cavitation Reynolds-Averaged Navier-Stokes (RANS) propeller sliding mesh multiphase flow

Annual advances of traditional Chinese medicine on tumor immunity regulation in 2021

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Traditional Medicine Research 2022年第6期7卷 83-92页

作者： Ru-Wei Huo Ming-Jie Zhan Bo zhu qi zhi School of Medicine and Integrative Medicine Nanjing University of Chinese MedicineNanjing 210023China School of Biopharmacy China Pharmaceutical UniversityNanjing 211198China Department of Radiology Affiliated Hospital of Nanjing University of Chinese MedicineNanjing 210029China

Traditional Chinese medicine has been used to treat more than 70%of cancer patients in *** Chinese medicine treatment includes the application of traditional Chinese medicine monomers,extracts,classical Chinese medicine compounds,self-made compounds,acupuncture,*** of the anti-tumor effects of traditional Chinese medicine are related to their immune-regulatory *** traditional Chinese medicines improve the sensitivity of chemotherapeutic drugs,enhance tumor-suppressive effects,and decrease adverse *** 2021,research papers from China accounted for about two-thirds of all the papers on traditional Chinese medicine and anti-tumor *** continues to lead the world in the field of anti-tumor immunity of traditional Chinese medicine,and the efficient and productive academic cooperation between China and other countries has promoted the rapid development of this *** this review,we summarize the research progress of traditional Chinese medicine in the field of tumor immunity in 2021 to provide new insights into mechanisms underlying the anti-tumor effects of traditional Chinese medicine.

关键词： traditional Chinese medicine natural product tumor immunity tumor microenvironment

A method to study interface diffusion of arsenic into a Nb-Ti microalloyed low carbon steel

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International Journal of Minerals,Metallurgy and Materials 2012年第9期19卷 821-826页

作者： Yuan-zhi zhu Jian-ping XU The Key Laboratory of the Ministry of Education of China for Ferrous Metallurgy and Resources Utilization Wuhan University of Science and Technology Wuhan 430081 China School of Materials and Metallurgy Wuhan University of Science and Technology Wuhan 430081 China

A novel diffusion couple method was used to investigate the interface diffusion of arsenic into a Nb-Ti microalloyed low carbon steel and its effects on phase transformation at the interface. It is discovered that the content of arsenic has great effect on grain growth and phase transformation at high temperature. When the arsenic content is no more than lwt%, there is no obvious grain growth and no obvious ferrite transitional region formed at the diffusion interface. However, when the arsenic content is no less than 5wt%, the grain grows very rapidly. In addition, the arsenic-enriched ferrite transitional layer forms at the diffusion interface in the hot-rolling process, which results from a slower diffusion rate of arsenic atoms than that of carbon in ferrite.

关键词： low carbon steel alloy steel arsenic diffusion bonding phase transformation grain growth

Resolution-dependent subsonic non-thermal line dispersion revealed by ALMA

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Research in Astronomy and Astrophysics 2021年第1期21卷 238-246页

作者： Nan-Nan Yue Di Li qi-Zhou Zhang Lei zhu Jonathan Henshaw Diego Mardones zhi-Yuan Ren National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Harvard-Smithsonian Center for Astrophysics 60 Garden StreetCambridgeMA 02138USA NAOC-UKZN Computational Astrophysics Centre University of Kwa Zulu-NatalDurban 4000South Africa Chinese Academy of Sciences South America Center for Astronomy China-Chile Joint Center for AstronomyCamino EI Observatorio#1515Las CondesSantiagoChile Max-Planck Institut fur Astronomie Konigstuhl 17D.69117 HeidelbergGermany Departameto de Astronomia Universidad de ChileCasilla 36-DSantiagoChile

We report here Atacama Large Millimeter/submillimeter Array(ALMA)N2H+(1-0)images of the Orion Molecular Cloud 2 and 3(OMC-2/3)with high angular resolution(3"or 1200 au)and high spatial dynamic *** a dataset from the ALMA main array,Atacama Compact Array(ACA),Nobeyama 45-m Telescope and Very Large Array(VLA)(providing temperature measurement on matching scales),we find that most of the dense gas in OMC-2/3 is subsonic(σQNT/cs=0.62)with a mean line width(△v)of 0.39 kms-1 full width at half maximum(FWHM).This is markedly different from the majority of previous observations of massive star-forming *** contrast,line widths from the Nobeyama Telescope are transonic at 0.69 km s-1(σNT/cs=1.08).We demonstrated that the larger line widths obtained by the single-dish telescope arose from unresolved sub-structures within their respective *** dispersions from larger scalesσls(as traced by the Nobeyama Telescope)can be decomposed into three components such thatσls2=σss2+σbm2+σrd2,where small-scaleσss is the line dispersion of each ALMA beam,bulk motionσbm is dispersion between peak velocity of each ALMA beam andσrd is the residual *** decomposition,though purely empirical,appears to be robust throughout our data *** supersonic line widths,commonly found in massive molecular clouds,are thus likely due to the effect of poor spatial *** observed non-thermal line dispersion(sometimes referred to as’turbulence’)transits from supersonic to subsonic at~0.05 pc scales in the OMC-2/3 *** transition could be commonly found with sufficient spatial(not just angular)resolution,even in regions with massive young clusters,such as the Orion molecular clouds studied here.

关键词： stars:formation ISM:clouds ISM:molecules ISM:kinematics and dynamics

Grain boundary segregation of minor arsenic and nitrogen at elevated temperatures in a microalloyed steel

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International Journal of Minerals,Metallurgy and Materials 2012年第5期19卷 399-403页

作者： Yuan-zhi zhu Zhe zhu Jian-ping Xu The Key Laboratory of the Ministry of Education of China for Ferrous Metallurgy and Resources Utilization Wulaan University of Science and Technology Wuhan430081 China School of Materials and Metallurgy Wuhan University of Science and Technology Wuhan 430081 China

Auger electron spectroscopy （AES） was used to investigate the grain boundary segregation of arsenic and nitrogen in a kind of microalloyed steel produced by a compact strip production （CSP） technology at 950 to 1100℃, which are similar to the hot working temperature of the steel on a CSP production line. It was discovered that arsenic segregated on grain boundaries when the steel was annealed at 950℃ for 2 h. When the annealing temperature increased to 1100℃, arsenic was also found to have segregated on grain boundaries in the early annealing stage, for instance, within the first 5 min annealing time. However, if the holding time of the steel at this temperature increased to 2 h, arsenic diffused away from grain boundaries into the matrix again. Nitrogen was not found to have segregated on grain boundaries when the steel was annealed at a relatively low temperature, such as 950℃. But when the annealing temperature increased to 1100℃, nitrogen was detected to have segregated at grain boundaries in the steel.

关键词： alloy steel arsenic nitrogen segregation grain boundaries

Experimental study of settling and drag on cuboids with square base

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Particuology 2011年第3期9卷 298-305页

作者： Jinsheng Wang Haiying qi Junzong zhu Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing 100084 China

The drag on non-spherical particles is an important basic parameter for multi-phase flows such as in biomass combustion, chemical blending, and mineral processing. Though there is much experimental research on such particles, there are few results for cuboids. This paper presents data for cuboids with a square base in static glycerin-water solutions of various volume concentrations. Complex motions were observed and characterized. A dimensionless expression is given for terminal velocity ut as a function of Archimedes number Ar which is used to develop an accurate correlation for friction factor CD. The accuracy of the correlation is 7.9% compared to experimental data in the literature. For both square plates and square rods, the terminal velocity per unit mass, ut/mp, was used to characterize the influence of narticle geometry on velocity, which was shown to be linear.

关键词： Cuboid particles Unsteady settling behavior Archimedes number Terminal velocity Drag coefficient

PN code acquisition algorithm in DS-UWB system based on threshold comparison criterion

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Journal of Systems Engineering and Electronics 2009年第1期20卷 216-222页

作者： qi Lina Gan Zongliang zhu Hongbo Coll. of Telecommunications & Information Engineering Nanjing Univ. of Posts and Telecommunication Nanjing 210003 P.R. China

The direct sequence ultra-wideband （DS-UWB） is a promising technology for short-range wireless communications. The UWB signal is a stream of very low power density and ultra-short pulses, and the great potential of DS-UWB depends critically on the success of timing acquisition. A rapid acquisition algorithm for reducing the acquisition time of the coarse pseudo-noise （PN） sequences is proposed. The algorithm utilizes the auxiliary sequence and bisearch strategy based on the threshold comparison criterion. Both theoretical analysis and simulation tests show that with the proposed search strategy and simple operations over the symbol duration at the receiver, the proposed algorithm can considerably reduce the acquisition time even as it maintains the PN sequence acquisition probability in the DS-UWB system over the dense multipath environment.

关键词： direct sequence ultra-wideband pseudo-noise code auxiliary sequence synchronization.