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Mitochondrial sirtuins,metabolism,and aging

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Journal of Genetics and Genomics 2022年第4期49卷 287-298页

作者： Zhejun ji guang-Hui liu jing Qu State Key Laboratory of Stem Cell and Reproductive Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China Institute for Stem Cell and Regeneration Chinese Academy of SciencesBeijing 100101China Beijing Institute for Stem Cell and Regenerative Medicine Beijing 100101China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Membrane Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China Advanced Innovation Center for Human Brain Protection National Clinical Research Center for Geriatric DisordersXuanwu Hospital Capital Medical UniversityBeijing 100053China

Maintaining metabolic homeostasis is essential for cellular and organismal health throughout *** signaling pathways that regulate metabolism also play critical roles in aging,such as PI3K/AKT,mTOR,AMPK,and sirtuins(SIRTs).Among them,sirtuins are known as a protein family with versatile functions,such as metabolic control,epigenetic modification and lifespan ***,by understanding how sirtuins regulate metabolic processes,we can start to understand how they slow down or accelerate biological aging from the perspectives of metabolic ***,we review the biology of SIRT3,SIRT4,and SIRT5,known as the mitochondrial sirtuins due to their localization in the mitochondrial ***,we will discuss canonical pathways that regulate metabolism more broadly and how these are integrated with aging ***,we will summarize the current knowledge about functional differences between SIRT3,SIRT4,and SIRT5 in metabolic control and integration in signaling ***,we will discuss how mitochondrial sirtuins regulate processes associated with aging and aging-related diseases.

关键词： Metabolism and aging regulation Mitochondrial sirtuins Aging-related diseases SIRT3 SIRT4 SIRT5

Influence of Reynolds Number on the Unsteady Aerodynamics of Integrated Aggressive Intermediate Turbine Duct

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Journal of Thermal Science 2018年第3期27卷 294-303页

作者： liu Hongrui liu Jun ji Lucheng DU Qiang liu guang WANG Pei School of Aerospace Engineering Beijing Institute of Technology Beijing 100081 China Key Laboratory of Light-Duty Gas-Turbine Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

The ultra-high bypass ratio turbofan engine attracts more and more attention in modern commercial engine due to advantages of high efficiency and low Specific Fuel Consumption(SFC). One of the characteristics of ultra-high bypass ratio turbofan is the intermediate turbine duct which guides the flow leaving high pressure turbine(HPT) to low pressure turbine(LPT) at a larger diameter, and this kind of design will lead to aggressive intermediate turbine duct(AITD) design concept. Thus, it is important to design the AITD without any severe loss. From the unsteady flow's point of view, in actual operating conditions, the incoming wake generated by HPT is unsteady which will take influence on boundary layer's transition within the ITD and LPT. In this paper, the three-dimensional unsteady aerodynamics of an AITD taken from a real engine is studied. The results of fully unsteady three-dimensional numerical simulations, performed with ANSYS-CFX(RANS simulation with transitional model), are critically evaluated against experimental data. After validation of the numerical model, the physical mechanisms inside the flow channel are analyzed, with an aim to quantify the sensitivities of different Reynolds number effect on both the ITD and LPT nozzle. Some general physical mechanisms can be recognized in the unsteady environment. It is recognized that wake characteristics plays a crucial role on the loss within both the ITD and LPT nozzle section, determining both time-averaged and time-resolved characteristics of the flow field. Meanwhile, particular attention needs to be paid to the unsteady effect on the boundary layer of LPT nozzle's suction side surface.

关键词： Intermediate Turbine Duct Unsteady Simulation Reynolds Number Flow Field Analysis

Upper Bound Solution of the Resisting Moment Bearing Capacity of A Composite Bucket Shallow Foundation of An Offshore Wind Turbine in Sand

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China Ocean Engineering 2022年第6期36卷 859-870页

作者： liu Run LI Tian-liang CHEN guang-si LIAN ji-jian State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

Bearing the large moment that is generated by the wind load that acts on the upper structure of offshore wind turbines is an important feature of their foundations that is different from other offshore structures.A composite bucket shallow foundation(CBSF)has been proposed by Tianjin University to address the soft geological conditions in the offshore regions of China for wind *** CBSF is a new type of foundation and is effective against large *** soil deformation test of a CBSF and the numerical simulation study under the same working conditions are carried out to determine the failure mechanism of a CBSF under moment *** resisting soil compression rateηm is defined as a new empirical parameter that indicates the ability of the soil inside the bucket to resist moment *** upper limit of the resisting moment bearing capacity of the bucket foundation is derived through the upper bound theorem of classical plasticity theory based on the failure *** calculation method is validated by tests of bucket models with different height-diameter ratios in sand under moment loading.

关键词： bucket foundation failure mechanism resisting moment bearing capacity upper bound theorem resisting soil compression rate

Numerical Investigation of the Effects of Rising Angle on Intermediate Turbine Duct and Nearby Turbines

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Journal of Thermal Science 2017年第5期26卷 421-430页

作者： liu Hongrui ji Lucheng liu Jun DU Qiang liu guang WANG Pei DU Meimei School of Aerospace Engineering Beijing Institute of Technology Laboratory of Light-duty Gas-turbine Institute of Engineering Thermophysics Chinese Academy of Sciences Petroleum Production Engineering Research Institute of Huabei Oilfield Company

In order to improve the efficiency, ultra-high bypass ratio engine attracts more and more attention because of its huge advantage, which has larger diameter low pressure turbine(LPT). This trend will lead to aggressive(high diffusion) intermediate turbine duct(ITD) design. It is necessary to guide the flow leaving high pressure turbine(HPT) to LPT at a larger diameter without any severe loss generating separation or flow disturbances. In this paper, eight ITDs with upstream swirl vanes and downstream LPT nozzle are investigated with the aid of numerical method. These models are modified from a unique ITD prototype, which comes from a real engine. Key parameters like area ratio, inlet height, and non-dimensional length of the ITDs are kept unchanged, while the rising angle(radial offset) is the only changed parameter which ranges from 8 degrees to 45 degrees. In this paper, the effects of rising angle(RA) on ITD, as well as nearby turbines, will be analyzed in detail. According to the investigation results, RA could be as large as 40 degrees in such model of this paper to escape separation; When RA increases, local inlet flow field of LPT nozzle appears to be with apparent variation; while a positive result is that outlet flow field could be kept almost unchanged through modifying blade profile. On the other hand, it seems optimistic that the overall total pressure loss could be kept nearly equivalent among different RA cases. And a valuable conclusion is that outer wall curvature is more important for pressure loss, which advises a clear direction for optimizing ITD.

关键词： Intermediate Turbine Duct Rising Angle Flow Field Analysis

Routing Protocol with Optimal Location of Aggregation Point in Wireless Sensor Networks

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The Journal of China Universities of Posts and Telecommunications 2006年第1期13卷 1-5页

作者： liu Yue-yang ji Hong YUE guang-xin School of Telecommunications Engineering Beijing University of Posts and Telecommunications Beijing 100876 P.R. China

A wireless sensor network is typically composed of hundreds, even thousands of tiny sensors used to monitor physical phenomena. As data collected by the sensors are often redundant, data aggregation is important for conserving energy. In this paper , we present a new routing protocol with optimal data aggregation. This routing protocol has good performance due to its optimal selection of aggregation point locations. This paper details the optimal selection of aggregation point locations.

关键词： wireless sensor networks routing protocol data aggregation

Spectrum efficiency sub-carrier and energy efficiency power allocation for downlink multi-user CoMP in multi-cell system

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The Journal of China Universities of Posts and Telecommunications 2014年第3期21卷 29-34页

作者： liu Kai LI Yi ji Hong WU Xu-guang School of Telecommunication Engineering Beijing University of Posts and Telecommunications

Coordinated multi-point transmission/reception （CoMP） was proposed currently as an effective technology to improve cell-edge throughput in next-generation wireless systems. Most of the existing work discussed clustering methods mostly to maximize the edge user throughput while neglecting the problem of energy efficiency, such as those algorithm clustering base stations （BSs） of better channel condition and BSs of worse channel condition together. In addition, BSs usually increase the transmit power to achieve higher throughput without any considering of interference caused to other users, that may result in energy waste. The authors focus on the throughput maximizing problem while fully considering energy saving problem in CoMP systems. A coefficient is defined to describe the fitness of clusters. Then a sub-carrier allocation algorithm with clustering method is put forward for CoMP downlink, which can save the transmit power of BS and increase the throughput. Furthermore a power allocation scheme is proposed based on non-cooperation game; in which the transmit power is decreased by BSs generally to reach the Nash equation （NE）. Simulation shows that the proposed sub-carrier allocation scheme and power allocation algorithm are better than the existing ones on users＇ throughput while consumes much less energy.

关键词： CoMP energy saving game theory power allocation sub-carrier allocation

RESREARCH ON FLUID CHARACTERISTIC WITHIN THE ROTATING-WING HEAT METER

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Journal of Hydrodynamics 2006年第4期18卷 458-463页

作者： liu Zheng-gang DU guang-sheng WANG Ning PAN ji-hong School of Energy Source and Power Engineering Shandong University Jinan 250061 China

In order to improve the performance of rotating-wing heat meter and reduce the cost of development, the three dimensions numerical calculations of the intemal fluid characteristic within a heat meter are carried out based on the standard k-e turbulent mode, the finite volume method and SIMPLE algorithm. The speed field and pressure distribution within heat meter are analyzed according to the result of numerical calculation. The flux measurement accuracy and pressure loss of basal meter are forecasted according to the calculated results. The calculated results of the impeller＇s rotating speed are compared with experimental results and prove the validity of the calculated results. This researches shows the calculated results can forecast the performance parameters of basal meter and can provide great help for design of the heat meter.

关键词： heat meter numerical calculation rotating-wing

First-principles study of structural, elastic, and electronic properties of CeB6 under pressure

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Frontiers of physics 2015年第6期10卷 117-126页

作者： Mei Tang Lei liu Yan Chenga guang-Fu ji Institute of Atomic and Molecular Physics College of Physical Science and Technology Sichuan University Chengdu 610065 China Key Laboratory of High Energy Density Physics and Technology of Ministry of Education Sichuan University Chengdu 610064 China National Key Laboratory for Shock Wave and Detonation Physics Research Institute of Fluid Physics Chinese Academy of Engineering Physics Mianyang 621900 China

We performed a first-principles study of the electronic, elastic, and thermal properties of the rareearth hexaboride CeB6 using the local density approximation （LDA） in consideration of the effective onsite Coulomb parameter Ueff. To systemically evaluate the effect of Ueff on the structure of the material, the dependences of the lattice parameter a0 and bulk modulus B on Ueff were examined in the framework of the LDA＋U and GGA（PBE）＋U scheme. We obtained a lattice constant a0, elastic constants Cij, and a bulk modulus B at 0 K and 0 GPa that were in good agreement with the experimental results and other theoretical findings. We focused on the electronic structure by analyzing the variation of the density of states with different Ueff values and pressures, which indicates the metallic characteristic of CeB6. Interestingly, the effect of high pressure was similar to that of increasing Ueff, as the peaks at the bottom of the conduction band moved to the high-energy region in both cases. The elastic constants Cij, bulk modulus B, shear modulus G, Young＇s modulus E, shear-sound velocity Vs, and longitudinal-sound velocity VL were calculated from 0 to 120 GPa. Additionally, the Debye temperature D and elastic Debye temperature E were systematically calculated using the thermodynamic methods in the range of 0-100 GPa. This research may provide a comprehensive understanding of the Kondo compound CeB6 and similar rare-earth hexaborides.

关键词： CeB6 structural properties elastic properties thermal properties electronic structure

k_(eff)uncertainty quantification and analysis due to nuclear data during the full lifetime burnup calculation for a small-sized prismatic high temperature gas-cooled reactor

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Nuclear Science and Techniques 2021年第11期32卷 105-118页

作者： Rong-Rui Yang Yuan Yuan Chen Hao ji Ma guang-Hao liu Fundamental Science on Nuclear Safety and Simulation Technology Laboratory College of Nuclear Science and TechnologyHarbin Engineering UniversityHarbin 150001China Department of Reactor Technology Beijing Institute of Nuclear EngineeringChina Nuclear Power Engineering Co.LtdBeijing 100089China

To benefit from recent advances in modeling and computational algorithms,as well as the availability of new covariance data,sensitivity and uncertainty analyses are needed to quantify the impact of uncertain sources on the design parameters of small prismatic high-temperature gascooled reactors(HTGRs).In particular,the contribution of nuclear data to the k_(eff)uncertainty is an important part of the uncertainty analysis of small-sized HTGR physical *** this study,a small-sized HTGR designed by China Nuclear Power Engineering Co.,*** selected for k_(eff)uncertainty analysis during full lifetime burnup *** of the cold zero power(CZP)condition and full lifetime burnup process were constructed using the Reactor Monte Carlo Code RMC for neutron transport calculation,depletion calculation,and sensitivity and uncertainty *** the sensitivity analysis,the Contribution-Linked eigenvalue sensitivity/Uncertainty estimation via Track length importance Characterization(CLUTCH)method was applied to obtain sensitive information,and the "sandwich" method was used to quantify the k_(eff)*** also compared the k_(eff)uncertainties to other typical *** results show that ^(235)U is the largest contributor to k_(eff)uncertainty for both the CZP and depletion conditions,while the contribution of ^(239)Pu is not very significant because of the design of low discharge *** is worth noting that the radioactive capture reaction of ^(28)Si significantly contributes to the k_(eff)uncertainty owing to its specific fuel ***,the k_(eff)uncertainty during the full lifetime depletion process was relatively stable,only increasing by 1.12%owing to the low discharge burnup design of small-sized *** numerical results are beneficial for neutronics design and core parameters optimization in further uncertainty propagation and quantification study for small-sized HTGR.

关键词： Small-sized HTGR SU analysis Nuclear data Burnup