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Experimental Study on the Start Up Performance of Flat Plate Pulsating Heat Pipe

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Journal of Thermal Science 2011年第2期20卷 150-154页

作者： Chaofa hu li Jia School of Mechanical Electronic and Control Engineering Beijing Jiaotong UniversityBeijing 100044 China

An experimental system of flat plate pulsating heat pipe was established and experimental research was carried out in this system to know the mechanism of heat transfer, start-up and operating characteristics. The factors, such as filling rate, heating power, heating method etc, which have great influence on the thermal performance of the plate pulsating heat pipe were discussed. The results indicate that heating power and filling rate are the important factors for the start-up of the plate pulsating heat pipe. The different start-up power is needed with different filling rate, and the start-up of the heat pipe in case of bottom heated is much easier than that of top heated. Increasing the heating power and enlarging the heating area can make the start-up easier. Heating power can also affect the start-up time of heat pipe under the condition of bottom heated, while it does not have some influence to the heat pipe of top heated. The thermal resistance of plate pulsating heat pipe is related with the heating power, and the higher the heating power is, the smaller the thermal resistance is. But the best filling rate which the heat pipe needs is different with different heating methods, and the performance of the heat pipe in the case of bottom heated is better than the others.

关键词： Plate pulsating heat pipe start-up power bottom heated top heated influence factors

Cobalt nitride enabled benzimidazoles production from furyl/aryl bio-alcohols and o-nitroanilines without an external H-source

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Frontiers of Chemical Science and Engineering 2023年第1期17卷 68-81页

作者： Chuanhui li li-Long Zhang hu li Song Yang State Key Laboratory Breeding Base of Green Pesticide&Agricultural Bioengineering Key Laboratory of Green Pesticide&Agricultural BioengineeringMinistry of EducationState-Local Joint Laboratory for Comprehensive Utilization of BiomassCenter for R&D of Fine ChemicalsGuizhou UniversityGuiyang 550025China

Benzimidazole derivatives have wide-spectrum biological activities and pharmacological effects,but remain challenging to be produced from biomass ***,we report a green hydrogen transfer strategy for the efficient one-pot production of benzimidazoles from a wide range of bio-alcohols and o-nitroanilines enabled by cobalt nitride species on hierarchically porous and recyclable nitrogen-doped carbon catalysts(Co/CN_(x)-T,T denotes the pyrolysis temperature)without using an external hydrogen source and base *** the tested catalysts,Co/CN_(x)-700 exhibited superior catalytic performance,furnishing 2-substituted benzimidazoles in 65%–92%*** mechanistic studies manifest that the coordination between Co^(2+)and N with appropriate electronic state on the porous nitrogen-doped carbon having structural defects,as well as the remarkable synergetic effect of Co/N dual sites contribute to the pronounced activity of Co/CN_(x)-700,while too high pyrolysis temperature may cause the breakage of the catalyst Co-N bond to lower down its ***,it is revealed that the initial dehydrogenation of bio-alcohol and the subsequent cyclodehydrogenation are closely correlated with the hydrogenation of nitro *** catalytic hydrogen transfer-coupling protocol opens a new avenue for the synthesis of N-heterocyclic compounds from biomass.

关键词： biomass conversion furanic compounds benzimidazoles hydrogen transfer bifunctional catalysis

Synthesis of Polycrystalline Nd∶YAG Nanopowders Used for Sintering Transparent Ceramics via Gel Combustion

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Journal of Rare Earths 2006年第z1期24卷 193-196页

作者： li Xianxue hu Zhanggui li Jiangtao Beijing Center for Crystal Research and Development Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100080 China Graduate School of Chinese Academy of Sciences Beijing 100039 China Beijing Center for Crystal Research and Development Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100080 China Functional Ceramic Research Group Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100080 China

Polycrystalline nano-sized neodymium doped yttrium aluminum garnet (Nd∶Y3Al5O12, Nd∶YAG) powders were synthesized via a gel combustion method using nitrates and citric acid as starting materials. The evolution of phase composition and micro-structure of the powders were characterized by X-ray powder diffraction, thermogravimetry/differential thermal analysis and scanning electron microscopy. Well-crystallized Nd∶YAG nano-sized powders could be obtained at 950 ℃ for 2 h. The resultant powders are well dispersed, have a relatively narrow size distribution with an average particle size of approximately 50 nm, and show excellent sinterability. These powders can be densified to 99.2% of the theoretical density by HP sintering at 1700 ℃ for 3 h under 20 MPa nitrogen pressure.

关键词： Nd∶YAG gel combustion sintering

Uniqueness Problem for the Backward Differential Equation of a Continuous-State Branching Process

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Acta Mathematica Sinica,English Series 2024年第8期40卷 1825-1836页

作者： Pei Sen li Zeng hu li School of Mathematics and Statistics Beijing Institute of TechnologyBeijing 100872P.R.China School of Mathematical Sciences Beijing Normal UniversityBeijing 100875P.R.China

The distributional properties of a multi-dimensional continuous-state branching process are determined by its cumulant semigroup,which is defined by the backward differential *** provide a proof of the assertion of Rhyzhov and Skorokhod(Theory ***.,1970)on the uniqueness of the solutions to the equation,which is based on a characterization of the process as the pathwise unique solution to a system of stochastic equations.

关键词： Continuous-state branching process multi-dimensional backward differential equation stochastic equation generator

Moments of Continuous-state Branching Processes with or Without Immigration

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Acta Mathematicae Applicatae Sinica 2020年第2期36卷 361-373页

作者： li-na JI Zeng-hu li Department of Mathematics Southern University of Science and TechnologyShenzhen 518055China School of Mathematical Sciences Beijing Normal UniversityBeijing 100875China

For a positive continuous function f satisfying some standard conditions,we study the f-moments of continuous-state branching processes with or without *** main results give criteria for the existence of the *** chara... 详细信息

关键词： branching process continuous-state immigration moments stochastic equation

Density functional calculations of large systems containing heavy elements by means of the regionalization algorithm

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Science China Chemistry 2004年第6期47卷 453-465页

作者： hu Xiangqian li Lemin State Key Laboratory of Rare Earth Materials and Applications College of Chemistry and Molecular Engineering Peking University Beijing 100871 China State Key Laboratory of Rare Earth Materials and Applications College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

The regionalized computational method is extended to the non-relativistic, scalar and 2-component relativistic density functional calculation of large systems containing transition series or heavy main-group metal elements. A large system is divided into several regions which can be considered as relatively independent quantum mechanical subsystems. Taking into account the Coulomb and exchange-correlation potentials as well as the Pauli repulsion exerted by the other subsystems, the Kohn-Sham equation related to subsystem K can be written as: $(F^K + F_P^K )C^K = S^K C^K \varepsilon ^K K = A,B,C \cdots ,$ where F K , C K , S K , ε K are the Fock matrix, the matrix of combination coefficients of orbitals, the overlap matrix of basis sets and the energy eigenvalue matrix, respectively. The matrix F K K reflects the Pauli repulsion from the other subsystems. F K may be non-relativistic, scalar or 2-component relativistic Fock matrix determined by the theoretical method related to the density functional calculations. The other matrices are mated with F K . Solving the Kohn-Sham equation for every subsystem and combining the results from the subsystem calculations, the electronic structural information of the whole system is derived. The density functional calculation of several molecules containing transition metal Ni or heavy main-group metal TI or Bi is performed by the afore-mentioned regionalization algorithm. The obtained results for each molecule are compared with those from the density functional calculation of that molecule in its entirety in order to check the feasibility of the regionalization algorithm. It is found that with sufficiently large regional basis set in the subsystem calculation the accuracy of the results calculated by the regionalization algorithm is essentially the same as that from the calculation of the molecule in its entirety. With proper smaller regional basis sets the accuracy of the results calculated with the regionalization algorithm c

关键词： density functional calculation, large system, transition metal, heavy element, regionalization algorithm.

In vitro culture of isolated primary hepatocytes and stem cell-derived hepatocyte-like cells for liver regeneration

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Protein & Cell 2015年第8期6卷 562-574页

作者： Chenxia hu Lanjuan li Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases State Key Laboratory for Diagnosis and Treatment of Infectious Diseases School of Medicine First Affiliated Hospital Zhejiang University Hangzhou 310006 China

Various liver diseases result in terminal hepatic failure, and liver transplantation, cell transplantation and artificial liver support systems are emerging as effective therapies for severe hepatic disease. However, all of these treatments are limited by organ or cell resources, so developing a sufficient number of functional hepatocytes for liver regeneration is a priority. liver regeneration is a complex process regulated by growth factors （GFs）, cytokines, transcription factors （TFs）, hormones, oxidative stress products, metabolic net- works, and microRNA. It is well-known that the function of isolated primary hepatocytes is hard to maintain; when cultured in vitro, these cells readily undergo dedifferentia- tion, causing them to lose hepatocyte function. For this mason, most studies focus on inducing stem cells, such as embryonic stem cells （ESCs）, induced pluripotent stem cells （iPSCs）, hepatic progenitor cells （HPCs）, and mesenchymal stem cells （MSCs）, to differentiate into hepatocyte-like cells （HLCs） in vitro. In this review, we mainly focus on the nature of the liver regeneration process and discuss how to main- tain and enhance in vitro hepatic function of isolated primary hepatocytes or stem cell-derived HLCs for liver regenera- tion. In this way, hepatocytes or HLCs may be applied for clinical use for the treatment of terminal liver diseases and may prolong the survival time of patients in the near future.

关键词： liver regeneration primary hepatocyte,stem cell hepatocyte-like cell in vitro culture

Convergence Rates of Wavelet Estimators in Semiparametric Regression Models Under NA Samples

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Chinese Annals of Mathematics,Series B 2012年第4期33卷 609-624页

作者： Hongchang hu li WU College of Mathematics and Statistics Hubei Normal University Huangshi 435002 Hubei China.

Consider the following heteroscedastic semiparametric regression model：where {Xi, 1 〈 i 〈 n} are random design points, errors {ei, 1 〈 i 〈 n} are negatively associated （NA） random variables, （r2 = h（ui）, and {ui} and {ti} are two nonrandom sequences on [0, 1]. Some wavelet estimators of the parametric component β, the non- parametric component g（t） and the variance function h（u） are given. Under some general conditions, the strong convergence rate of these wavelet estimators is O（n- 1 log n）. Hence our results are extensions of those re, sults on independent random error settings.

关键词： Semiparametric regression model Wavelet estimate Negativelyassociated random error Strong convergence rate

Mean Index for Non-periodic Orbits in Hamiltonian Systems

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Acta Mathematica Sinica,English Series 2022年第1期38卷 291-310页

作者： Xi Jun hu li WU School of Mathematics Shandong UniversityJi’nan 250100P.R.China

In this paper,we define mean index for non-periodic orbits in Hamiltonian systems and study its *** general,the mean index is an interval in R which is uniformly continuous on the *** show that the index interval is a point for a quasi-periodic *** mean index can be considered as a generalization of rotation number defined by Johnson and Moser in the study of almost periodic Schr¨odinger *** by their works,we study the relation of Fredholm property of the linear operator and the mean index at the end of the paper.

关键词： Mean index Maslov-type index quasi-periodic orbit Fredholm operator