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Experimental and Numerical Studies of a Microscale Internal Combustion Swing Engine(MICSE)

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Journal of Thermal Science 2021年第5期30卷 1705-1717页

作者： du ning KONG Wenjun Key Laboratory of Light-duty Gas-Turbine Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100039China Ning Du School of Astronautics Beihang UniversityBeijing100191China

In this paper,the operation characteristics of a microscale internal combustion swing engine(MICSE)were investigated experimentally and *** energy flow path of MICSE was comprehensively analyzed based on the first law of *** accuracy of zero-dimensional model was verified by *** indicative thermal efficiency of the engine increases first and then decreases with the increase of equivalent ratio or ignition advance *** results show that there exists an optimum equivalent ratio and ignition advance angle during *** maximum efficiency of the engine reaches 12.5%when the equivalent ratio and ignition advance angle are 0.8 and−0.553,*** can operate normally when the equivalent ratio is greater than *** peak value of net heat release rate lags behind that of pressure change,which is different from the conventional crank *** and simulation results show that the leakage of MICSE is serious,and it is the main loss of *** order of energy terms is as follows:leakage loss>exhaust loss>heat loss>indicative work.

关键词： microscale internal combustion swing engine indicative thermal efficiency equivalent ratio ignition advance angle leakage

Property analysis of logic Petri nets by marking reachability graphs

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Frontiers of Computer Science 2014年第4期8卷 684-692页

作者： Yuyue du Yuhui ning College of Information Science and Engineering Shandong University of Science and Technology Qingdao 266590 China

Logic Petri nets （LPNs） are suitable to describe and analyze batch processing functions and passing value indeterminacy in cooperative systems. To investigate the dynamic properties of LPNs directly, a new method for analyzing LPNs is proposed based on marking reachability graphs in this paper. Enabled conditions of transitions are obtained and a marking reachability graph is constructed. All reach- able markings can be obtained based on the graph; the fairness and reversibility of LPNs are analyzed. Moreover, the computing complexity of the enabled conditions and reachable markings can be reduced by this method. The advantages of the proposed method are illustrated by examples and analysis.

关键词： logic Petri nets enabled condition reachable marking graph fairness reversibility

A FAST STOCHASTIC GALERKIN METHOD FOR A CONSTRAINED OPTIMAL CONTROL PROBLEM GOVERNED BY A RANDOM FRACTIONAL DIFFUSION EQUATION

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Journal of Computational Mathematics 2018年第2期36卷 259-275页

作者： ning du Wanfang Shen School of Mathematics Shandong Univeristy Jinan Shandong 250100 China School of Mathematic and Quantitative Economics Shandong University of Finance and Economics Jinan Shandong 250100 China

We develop a fast stochastic Galerkin method for an optimal control problem governed by a random space-fractional diffusion equation with deterministic constrained control. Optimal control problems governed by a fractional diffusion equation tends to provide a better description for transport or conduction processes in heterogeneous media. Howev- er, the fractional control problem introduces significant computation complexity due to the nonlocal nature of fractional differential operators, and this is further worsen by the large number of random space dimensions to discretize the probability space. We ap- proximate the optimality system by a gradient algorithm combined with the stochastic Galerkin method through the discretization with respect to both the spatial space and the probability space. The resulting linear system can be decoupled for the random and spatial variable, and thus solved separately. A fast preconditioned Bi-Conjugate Gradient Stabilized method is developed to efficiently solve the decoupled systems derived from the fractional diffusion operators in the spatial space. Numerical experiments show the utility of the method.

关键词： Constrained optimal control Fractional diffusion Stochastic Galerkin method,Fast Fourier transform Preconditioned Bi-Conjugate Gradient Stabilized method.

Does a low solar cycle minimum hint at a weak upcoming cycle?

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Research in Astronomy and Astrophysics 2010年第10期10卷 950-955页

作者： Zhan-Le du Hua-ning Wang Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

The maximum amplitude （Rm） of a solar cycle, in the term of mean sunspot numbers, is well-known to be positively correlated with the preceding minimum （Rmin）. So far as the long term trend is concerned, a low level of Rmin tends to be followed by a weak Rm, and vice versa. We found that the evidence is insufficient to infer a very weak Cycle 24 from the very low Rmin in the preceding cycle. This is concluded by analyzing the correlation in the temporal variations of parameters for two successive cycles.

关键词： Sun activity -- Sun general -- sunspots

The prediction method of similar cycles

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Research in Astronomy and Astrophysics 2011年第12期11卷 1482-1492页

作者： Zhan-Le du Hua-ning Wang Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

The concept of degree of similarity （η）, is proposed to quantitatively describe the similarity of a parameter （e.g. the maximum amplitude Rmax） of a solar cycle relative to a referenced one, and the prediction method of similar cycles is further developed. For two parameters, the solar minimum （Rmin） and rising rate （βa）, which can be directly measured a few months after the minimum, a synthesis degree of similarity （ηs） is defined as the weighted-average of the η values around Rmin and βa, with the weights given by the coefficients of determination of Rmax with Rmin and βa, respectively. The monthly values of the whole referenced cycle can be predicted by averaging the corresponding values in the most similar cycles with the weights given by the ηs values. As an application, Cycle 24 is predicted to peak around January 2013 i8 （month） with a size of about Rmax = 84 ± 17 and to end around September 2019.

关键词： Sun: activity -- Sun: general -- sunspots

SETD3-mediated histidine methylation of MCM7 regulates DNA replication by facilitating chromatin loading of MCM

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Science China Life Sciences 2025年第03期 793-808页

作者： Hongguo duan Shuang Wang Wen-Jie Shu Yongjia Tong Hai-Zhen Long Guohong Li Hai-ning du Meng-Jie Zhao Hubei Key Laboratory of Cell Homeostasis College of Life Sciences Tai Kang Center for Life and Medical Sciences Frontier Science Center for Immunology and Metabolism Emergency Center Zhongnan Hospital of Wuhan University RNA Institute Wuhan University The Institute for Advanced Studies Wuhan University Shenzhen Bay Laboratory Hubei Key Laboratory of Cell Homeostasis College of Life Sciences Tai Kang Center for Life and Medical Sciences Frontier Science Center for Immunology and Metabolism Wuhan University

The minichromosome maintenance complex(MCM) DNA helicase is an important replicative factor during DNA replication. The proper chromatin loading of MCM is a key step to ensure replication initiation during S phase. Because replication initiation is regulated by multiple biological cues, additional changes to MCM may provide better understanding towards this event. Here, we report that histidine methyltransferase SETD3 promotes DNA replication in a manner dependent on enzymatic activity. Nascent-strand sequencing(NS-seq)shows that SETD3 regulates replication initiation, as depletion of SETD3 attenuates early replication origins firing. Biochemical studies reveal that SETD3 binds MCM mainly during S phase, which is required for the CDT1-mediated chromatin loading of MCM. This MCM loading relies on histidine-459 methylation(H459me) on MCM7 which is catalyzed by SETD3. Impairment of H459 methylation attenuates DNA synthesis and chromatin loading of MCM. Furthermore, we show that CDK2 phosphorylates SETD3 at Serine-21 during the G1/S phase,which is required for DNA replication and cell cycle progression. These findings demonstrate a novel mechanism by which SETD3 methylates MCM to regulate replication initiation.

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Secondary and activated X(γ)radiation of SPHIC particle therapy facility

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Nuclear Science and Techniques 2021年第4期32卷 84-91页

作者： Wei-Ming Sun ning du Wen-Dong Tian Lan Wang Department of Medical Management Shanghai Proton and Heavy Ion CenterShanghai Engineering Research Center of Proton and Heavy Ion Radiation TherapyShanghai 201315China Siemens Healthineers Ltd. Shanghai 201321China

We report the secondary X(γ)radiation from the accelerator in a normal operating state and activated X(γ)radiation from the accelerator devices when the accelerator stops operating in the cancer treatment facility of the Shanghai Proton and Heavy Ion Center(SPHIC).These radiation measurements show us the structural radiation distribution along the beam lines and devices inside the accelerator room when the beam is on and off and can support the radiation protection design of the accelerator facility used for cancer treatment and help evaluate the accumulated radiation dose in the case of an emergency,such as a personal safety system failure or a radiation *** radiation dose rate measured in this facility shows that the facility is safe from the radiation protection *** shooting the quality assurance(QA)beam,the radiation dose rate in the treatment room was also measured to investigate the radiation dose space distribution and decay time *** addition,the time period before safely entering the treatment room after determining the shooting of the QA beam is recommended to be approximately 5 min.

关键词： Secondary radiation Activated radiation Nuclear safety and radiation protection Dose rate Accelerator

A Fast State-Based Peridynamic Numerical Model

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Communications in Computational Physics 2020年第1期27卷 274-291页

作者： ning du Xu Guo Hong Wang School of Mathematics Shandong UniversityJinan 250100China Department of Mathematics The Chinese University of Hong KongShatinN.T.Hong Kong Department of Mathematics University of South CarolinaSCUSA

The peridynamic(PD)theory is a reformulation of the classical theory of continuum solid mechanics and is particularly suitable for the representation of discontinuities in displacement fields and the description of cracks and their evolution in materials,which the classical partial differential equation(PDE)models tend to fail to ***,the PD models yield numerical methods with dense stiffness matrices which requires O(N^(2))memory and O(N^(3))computational complexity where N is the number of spatial ***,the PD models are deemed to be computationally very expensive especially for problems in multiple space ***-based PD models,which were developed lately,can be treated as a great improvement of the previous bond-based PD *** state-based PD models have more complicated structures than the bond-based PD *** this paper we develop a fast collocation method for a state-based linear PD model by exploring the structure of the stiffness matrix of the numerical *** method has an O(N)memory requirement and computational complexity of O(N log N)per Krylov sub-space *** methods are presented to show the utility of the method.

关键词： State-based peridynamic model fast algorithm collocation method stiffness matrix

Bootstrapping Calabi-Yau quantum mechanics

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Communications in Theoretical Physics 2022年第9期74卷 207-217页

作者： Bao-ning du Min-Xin Huang Pei-Xuan Zeng Interdisciplinary Center for Theoretical Study University of Science and Technology of ChinaHefeiAnhui 230026China Peng Huanwu Center for Fundamental Theory HefeiAnhui 230026China

Recently,a novel bootstrap method for numerical calculations in matrix models and quantum mechanical systems was *** apply the method to certain quantum mechanical systems derived from some well-known local toric Calabi-Yau geometries,where the exact quantization conditions have been conjecturally related to topological string *** find that the bootstrap method provides a promising alternative for the precision numerical calculations of the energy *** improvement in our approach is to use a larger set of two-dimensional operators instead of one-dimensional *** also apply our improved bootstrap methods to some non-relativistic models in the recent literature and demonstrate better numerical accuracies.

关键词： bootstrap Calabi-Yau space quantum mechanics