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Nano Research 2013年第2期6卷 87-98页

作者： Hongmei du Lifang Jiao Qinghong Wang Jiaqin Yang lijing Guo Yuchang Si Yijing Wang Huatang Yuan Institute of New Energy Material Chemistry Key Laboratory of Advanced Energy Materials Chemistry (MOE) Tianjin Key Lab of Metal and Molecule-based Material Chemistry Nankai University Tianjin 300071 China

Co3O4 hollow spheres assembled from nanoparticles have been successfully synthesized by a one-pot hydrothermal carbonization and calcination method. In this method, carbon spheres obtained through hydrothermal carbonization at a low temperature of 140 ℃ are used as sacrificial templates. The carbonization process was monitored by Fourier transform infrared spectroscopy （FT-IR） and Raman spectroscopy. Both the carbon sphere soft templates and the NH3 released from hexamethylenetetramine play key roles in the formation of these novel hollow structures. The formation of the Co3O4 hollow spheres using hydrothermal carbon spheres as templates can be attributed to the synergetic effect of metal ion adsorption and heterogeneous nucleation of Co（OH）2, which is different from the traditional adsorption theory. The as-obtained Co3O4 hollow microspheres exhibit excellent cycling performance and good rate capacity when used as electrode materials in supercapacitors, which can be attributed to the small particle size of Co3O4 and the sufficient space available to interact with the electrolytes. This facile strategy may be extended to synthesize other metal oxide hollow spheres, which may find application in sensors and catalysts due to their unique structural features.

关键词： hydrothermal carbonization calcination hollow spheres adsorption supercapacitors

A Low-Complexity Resource Allocation Scheme for OFDMA Multicast Systems with Proportional Fairness

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China Communications 2018年第1期15卷 1-11页

作者： lijing Jiang Rongfang Song Nanjing University of Posts and Telecommunications Nanjing 210003 China

A low-complexity optimization scheme is proposed to balance the tradeoff between system capacity and proportional fairness in orthogonal frequency division multiple access(OFDMA) based multicast systems. The major challenge is to solve the non-convexity optimization problem with strict proportional fairness. Constrained team progress algorithm(CTPA) solves this non-convexity problem by allocating sub-channels to each group based on sub-channel gains and proportional fairness constraint. Mapping power algorithm(MPA) guarantees strict proportional fairness with efficient power allocation which utilizes the mapping relation between power and throughput. CTPA-MPA is analyzed in three aspects: complexity, fairness and efficiency. We numerically show that when the system capacity is slightly increased in lower power region compared with several previous approaches, CTPA-MPA improves the proportional fairness in a typical scenario with 4 groups over 16 sub-channels, while reducing the complexity from exponential to linear in the number of sub-channels. It is also proved available in a more complicated system.

关键词： resource allocation OFDMA multicast team progress algorithm (TPA)

An Oscillating Operator Related to Wave Equations in the Block Spaces

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Acta Mathematica Sinica,English Series 2011年第1期27卷 83-96页

作者： Dashan FAN lijing SUN Department of Mathematical Sciences University of Wisconsin-Milwaukee Milwaukee WI53201 USA

In this article, we study certain oscillating multipliers related to Cauchy problem for the wave equations on the Euclidean space and on the torus. We obtain that, at the end point, these operators are bounded from th... 详细信息

关键词： Wave equations block spaces oscillatory integrals

Scalar dark energy models and scalar–tensor gravity:theoretical explanations for the accelerated expansion of the present Universe

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Communications in Theoretical Physics 2024年第10期76卷 158-187页

作者： Peixiang Ji lijing Shao Department of Astronomy School of PhysicsPeking UniversityBeijing 100871China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China

The reason for the present accelerated expansion of the Universe stands as one of the most profound questions in the realm of science,with deep connections to both cosmology and fundamental *** a cosmological point of view,physical models aimed at elucidating the observed expansion can be categorized into two major classes:dark energy and modified *** review various major approaches that employ a single scalar field to account for the accelerating phase of our present *** system analysis was employed in several important models to find cosmological solutions that exhibit an accelerating phase as an *** scalar field models of dark energy,we consistently focused on addressing challenges related to the fine-tuning and coincidence problems in cosmology,as well as exploring potential solutions to *** scalar–tensor theories and their generalizations,we emphasize the importance of constraints on theoretical parameters to ensure overall consistency with experimental *** or theories that could potentially explain the Hubble tension are also emphasized throughout this review.

关键词： dark energy modified gravity quintessence dynamic system cosmology

Modeling high-speed cutting of SiC_(p)/Al composites using a semi-phenomenologically based damage model

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Chinese Journal of Aeronautics 2021年第8期34卷 218-229页

作者： Junfeng XIANG lijing XIE Feinong GAO School of Civil Aviation Northwestern Polytechnical UniversityXi'an 710072China Key Laboratory of Fundamental Science for Advanced Machining Beijing Institute of TechnologyBeijing 100081China

In this paper,we attempts to investigate cutting mechanisms in high-speed cutting of Al6061/Si C_(p)/15p composites using a semi-phenomenologically based damage model in the equivalent homogeneous material(EHM)*** combining macroscale EHM modeling and underlying microscale physical mechanisms,a feasible semi-phenomenological plastic model is proposed for prediction of cutting forces and chip morphology during high-speed turning Al6061/Si C_(p)/15p *** model incorporates the modified Weibull weakest-link effect to represent the strain-based damage evolution in large *** proposed semi-phenomenological constitutive model is implemented by compiling material subroutines into cutting finite element(FE)*** effects of the critical shear stresses on chip formation that depend on the toolchip frictional coefficient are accounted for in the cutting FE *** chip formation mechanism affecting material removal behaviors during high-speed turning is further *** capabilities of the proposed constitutive model are evaluated by comparing cutting forces and chip morphologies between experiments and simulations at different cutting speeds associated with strain *** EHM-based and microstructure-based models are further compared in both computational efficiency and *** simulation results show that the developed semiphenomenological constitutive formalism and cutting model are promising and efficient tools for further investigation of dynamic mechanical and cutting behaviors of particle-reinforced composites with different volume fraction and particle size.

关键词： Chip morphology Damage evolution High-speed cutting Semi-phenomenological plasticity SiC_(p)/Al composites

Protein Function Prediction Based on Active Semi-supervised Learning

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Chinese Journal of Electronics 2016年第4期25卷 595-600页

作者： WANG Xuesong CHENG Yuhu LI lijing School of Information and Electrical Engineering China University of Mining and Technology

In our study,the active learning and semisupervised learning methods are comprehensively used for label delivery of proteins with known functions in Proteinprotein interaction(PPI) network so as to predict the functions of unknown *** the real PPI network is generally observed with overlapping protein nodes with multiple functions,the mislabeling of overlapping protein may result in accumulation of prediction *** this reason,prior to executing the label delivery process of semi-supervised learning,the adjacency matrix is used to detect overlapping *** the topological structure description of interactive relation between proteins,PPI network is observed with party hub protein nodes that play an important role,in co-expression with its ***,to reduce the manual labeling cost,party hub proteins most beneficial for improvement of prediction accuracy are selected for class labeling and the labeled party hub proteins are added into the labeled sample set for semisupervised learning *** the experimental results of real yeast PPI network show,the proposed algorithm can achieve high prediction accuracy with few labeled samples.

关键词： Active learning Semi-supervised learning Protein function prediction Overlapping protein Party hub protein

Development of a Percentile Based Three-dimensional Model of the Buttocks in Computer System

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Chinese Journal of Mechanical Engineering 2016年第3期29卷 633-640页

作者： WANG lijing HE Xueli LI Hongpeng Fundamental Science on Ergonomics and Environment Control Laboratory Beihang University

There are diverse products related to human buttocks, which need to be designed, manufactured and evaluated with 3D buttock model. The 3D buttock model used in present research field is just simple approximate model similar to human buttocks. The 3D buttock percentile model is highly desired in the ergonomics design and evaluation for these products. So far, there is no research on the percentile sizing system of human 3D buttock model. So the purpose of this paper is to develop a new method for building three-dimensional buttock percentile model in computer system. After scanning the 3D shape of buttocks, the cloud data of 3D points is imported into the reverse engineering software（Geomagic） for the reconstructing of the buttock surface model. Five characteristic dimensions of the buttock are measured through mark-points after models being imported into engineering software CATIA. A series of space points are obtained by the intersecting of the cutting slices and 3D buttock surface model, and then are ordered based on the sequence number of the horizontal and vertical slices. The 1st, 5th, 50 th, 95 th, 99 th percentile values of the five dimensions and the spatial coordinate values of the space points are obtained, and used to reconstruct percentile buttock models. This research proposes a establishing method of percentile sizing system of buttock 3D model based on the percentile values of the ischial tuberosities diameter, the distances from margin to ischial tuberosity and the space coordinates value of coordinate points, for establishing the Nth percentile 3D buttock model and every special buttock types model. The proposed method also serves as a useful guidance for the other 3D percentile models establishment for other part in human body with characteristic points.

关键词： three-dimensional percentile buttock model point-cloud

The Energy Expenditure and Nutritional Status of College Students——Ⅰ.The Energy Cost and the Total Energy Expenditure per Day

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Biomedical and Environmental Sciences 1991年第3期4卷 295-303页

作者： lijing YANWENYU DepartmentofNutritionandFoodHygiene SchoolofPublicHecalthShanghaiMedicalUniversityShanghai200032 De

The energy cost of major activities was determined in healthy students. Among the 606 medical students, 319 were males and 287 were females. Their ages ranged from 18 to 24 years. Douglas' method was used to measure energy cost of each of a total of 42 activities, as well as that of the basal metabolic rates (BMR), resting metabolic rates (RMR) and the total energy expenditure per day under normal situations. The average RMR of male and female subjects were 0.669±0.033 and 0.656±0.030 kcal/sq.m/min respectively. The total energy expenditure per day of male students were 2706 kcal, and 2373 kcal for female students. The energy cost of single activities can be used as the basal data in studies of energy metabolism.

关键词： In rate The Energy Expenditure and Nutritional Status of College Students The Energy Cost and the Total Energy Expenditure per Day

Note on a new fundamental length scale l instead of the Newtonian constant G

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Science China(Physics,Mechanics & Astronomy) 2011年第10期54卷 1771-1774页

作者： SHAO lijing MA BoQiang School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China Center for High Energy Physics Peking UniversityBeijing 100871China Center for History and Philosophy of Science Peking UniversityBeijing 100871China

The newly proposed entropic gravity suggests gravity as an emergent force rather than a fundamental one. In this approach,the Newtonian constant G does not play a fundamental role any more, and a new fundamental constant is required to replace itsposition. This request also arises from some philosophical considerations to contemplate the physical foundations for the unificationof theories. We here consider the suggestion to derive G from more fundamental quantities in the presence of a new fundamentallength scale l, which is suspected to originate from the structure of quantum space-time, and can be measured directly from Lorentz-violating observations. Our results are relevant to the fundamental understanding of physics, and more practically, of natural units,as well as explanations of experimental constraints in searching for Lorentz violation.

关键词： physical constants entropic gravity Lorentz violation

Temporal-Spatial Dichotomous Noises

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Communications in Theoretical Physics 2004年第1X期42卷 55-58页

作者： lijing-Hui HANYin-Xia CenterforNonlinearStudies InstituteofAppliedPhysicsandComputationalMathematicsP.O.Box8009(28)Beijing100088China

In this paper, we consider three kinds of temporal-spatial dichotomous noises. Three systems driven by these noises are studied, respectively. The master equations for these systems are derived.

关键词：二叉噪声控制方程随机系统随机响应随机变量非线性物理