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Possible shape coexistence in Ne isotopes and the impurity effect of Λ hyperon

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Science China(Physics,Mechanics & Astronomy) 2021年第8期64卷 29-40页

作者： Chen Chen Qian-Kun sun yu-Xiao Li Ting-Ting sun School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China

The possible shape coexistence in even-even Ne isotopes and the impurity effects of the sΛ and pΛ hyperons are explored employing the multidimensionally constrained relativistic-mean-field(MDC-RMF) model with the PK1 parameter set for the N N interaction and PK1-Y1 for the ΛN interaction. The quadrupole deformation potential energy surfaces(PESs), nuclear deformations, nuclear radii, binding energies, and density distributions of the hypernuclei and core nuclei are examined. The possible shape coexistence in ^(24,26,28)Ne is predicted with small energy differences of 140, 336, and 128 keV, respectively, between the two local energy minima. Different impurity effects of the sΛand pΛ hyperons are revealed. The sΛ hyperon exhibits clear shrinkage effects, which reduce the nuclear size and facilitate a spherical nuclear shape. The prolate pΛhyperon on the 1/2^(-)[110] orbital renders the nuclear shape more prolate, while the oblate pΛ hyperon on the 3/2^(-)[101] or 1/2^(-)[101] orbital renders the nuclei more oblate. Moreover, the Λ hyperon can increase the probabilities of the shape coexistence by reducing the energy differences between the two local energy minima, although the shape coexistence may disappear owing to the vanishment of one energy minimum on the flat energy surface.

关键词： single-Λhypernuclei shape coexistence impurity effects Ne isotope

Performance Analysis of an Integrated Supercritical CO_(2) Recompression/Absorption Refrigeration/Kalina Cycle Driven by Medium-Temperature Waste Heat

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Journal of Thermal Science 2022年第6期31卷 2051-2067页

作者： SU Ruizhi yu Zeting WANG Daohan sun Bo sun Jia’nan School of Energy and Power Engineering Shandong UniversityJi'nan 250061China Shandong Engineering Laboratory for High-Efficiency Energy Conservation and Energy Storage Technology&Equipment Shandong UniversityJi'nan 250061China School of Electrical Engineering Shandong UniversityJi'nan 250061China School of Control Science and Engineering Shandong UniversityJi'nan 250061China

A novel power and cooling cogeneration system which combines a supercritical CO_(2) recompression cycle(SCRC), an ammonia-water absorption refrigeration cycle(AARC) and a Kalina cycle(KC) is proposed and investigated for the recovery of medium-temperature waste heat. The system is based on energy cascade utilization, and the waste heat can be fully converted through the simultaneous operation of the three sub-cycles. A steady-state mathematical model is built for further performance study of the proposed system. When the exhaust temperature is 505℃, it is shown that under designed conditions the thermal efficiency and exergy efficiency reach 30.74% and 61.55%, respectively. The exergy analysis results show that the main exergy destruction is concentrated in the heat recovery vapor generator(HRVG). Parametric study shows that the compressor inlet pressure, the SCRC pressure ratio, the main compressor and the turbine I inlet temperature, and the AARC generator pressure have significant effects on thermodynamic and economic performance of the combined system. The findings in this study could provide guidance for system design to achieve an efficient utilization of medium-temperature waste heat(e.g., exhaust heat from gas turbine, high-temperature fuel cells and internal combustion engine).

关键词： waste heat utilization cogeneration system supercritical CO_(2)recompression cycle absorption refrigeration cycle Kalina cycle

Strict Stability of Impulsive Differential Equations

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Acta Mathematica Sinica,English Series 2006年第3期22卷 813-818页

作者： yu ZHANG Ji Tao sun Department of Applied Mathematics Tongji University

In this paper, we will extend the strict stability to impulsive differential equations. By using Lyapunov functions, we will get some criteria for the strict stability of impulsive differential equations, and we can see that impulses do contribute to the system＇s strict stability behavior. An example is also given in this paper to illustrate the efficiency of the obtained results.

关键词： Impulsive differential equation Strict stability Lyapunov function

Tree-ring based PDSI reconstruction since 1853 AD in the source of the Fenhe River Basin,Shanxi Province,China

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Science China Earth Sciences 2012年第11期55卷 1847-1854页

作者： sun JunYan LIU yu sun Bo WANG Ruiyuan The State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an 710075China Department of Environmental Science and Technology School of Human Settlements and Civil EngineeringXi’an Jiaotong UniversityXi’an 710049China Graduate University of Chinese Academy of Sciences Beijing 100049China

A robust tree-ring-width chronology was developed from two Pinus tabulaeformis sampling sites in the source of the Fenhe River,Shanxi Province,*** on the tree-ring-width indices,a 157-year long Palmer Drought Severity Index(PDSI) was reconstructed,which explains 53.7% of the variance of the modeled PDSI over the common period *** drought periods in the study area include 1914-1931 and 1970 to the present,whereas the wet periods were 1866-1892 and *** drought of 1914-1931 was a severe long-lasting drought with a low inter-annual variability,and the drought of 1970-2009 was an overall long-term drought with a high inter-annual *** period of 1866-1892 is a continuously wet period with a low inter-annual variability and the period of 1932-1969 is an overall long-term wet period with a high inter-annual *** reconstructed PDSI series in the source of the Fenhe River shows synchronous variations with the regional drought/wetness *** correlation analyses indicate that the higher correlations lie exclusively in the Fenhe River *** indicates that the reconstructed PDSI has regional representativeness and can represent the drought history of the entire Fenhe River Basin to some ***,the reconstructed PDSI matches with the variability of the per unit yield of summer grain crops in Shanxi Province very well and they have significant *** a long-term perspective the reconstructed PDSI series could supply scientific and valuable information to the water resources management and then help the sustainable development in agricultural production,economic development,and ecosystem balance.

关键词： tree-ring-width indices PDSI reconstruction drought the Fenhe River Basin China

基于目标检测和多视图几何的动态SLAM算法

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现代电子技术 2025年第1期48卷 135-143页

作者：喻擎苍董根阳方才威孙树森浙江理工大学计算机科学与技术学院(人工智能学院) 浙江杭州310018

目前大多数的SLAM系统主要针对静态场景,然而,在实际环境中不可避免地存在许多动态对象,这将大大降低算法的鲁棒性和相机的定位精度。针对动态对象造成的轨迹偏差问题,文中提出一种结合目标检测网络和多视图几何结构的动态SLAM算法。首... 详细信息

目前大多数的SLAM系统主要针对静态场景,然而,在实际环境中不可避免地存在许多动态对象,这将大大降低算法的鲁棒性和相机的定位精度。针对动态对象造成的轨迹偏差问题,文中提出一种结合目标检测网络和多视图几何结构的动态SLAM算法。首先,基于YOLOv5算法框架,将骨干网络CSPDarkNet-53替换为轻量型L-FPN(Lite-FPN)结构,并使用VOC2007数据集进行预训练。与YOLOv5s原始模型相比,新网络的计算量减少了45.73%,检测速率提高了31.90%;然后,将检测物体划分为高动态对象、中动态对象以及低动态对象,利用多视图几何方法计算阈值,并根据阈值对中高动态对象进行二次检测,以决定是否剔除预测框中的特征点;最后,在TUM数据集上的实验结果显示,该方法在定位精度上平均提升了82.08%,证明了其在准确性方面的显著改进。

关键词：同步定位与地图构建动态环境多视图几何结构目标检测特征点轻量型

Computational fluid dynamics simulations of respiratory airflow in human nasal cavity and its characteristic dimension study

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Acta Mechanica Sinica 2008年第2期24卷 223-228页

作者： Jun Zhang Yingxi Liu Xiuzhen sun Shen yu Chi yu State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116024 China Department of Otorhinolaryngology the Second Affiliated Hospital of Dalian Medical University Dalian 116027 China

To study the airflow distribution in human nasal cavity during respiration and the characteristic parameters of nasal structure, three-dimensional, anatomically accurate representations of 30 adult nasal cavity models were recons- tructed based on processed tomography images collected from normal people. The airflow fields in nasal cavities were simulated by fluid dynamics with finite element software ANSYS. The results showed that the difference of human nasal cavity structure led to different airflow distribution in the nasal cavities and variation of the main airstream passing through the common nasal meatus. The nasal resistance in the regions of nasal valve and nasal vestibule accounted for more than half of the overall resistance. The characteristic model of nasal cavity was extracted on the basis of characteristic points and dimensions deduced from the original models. It showed that either the geometric structure or the airflow field of the two kinds of models was similar. The characteristic dimensions were the characteristic parameters of nasal cavity that could properly represent the original model in model studies on nasal cavity.

关键词： Nasal cavity Characteristic dimension Three-dimensional reconstruction Numerical simulation of flowfield Computational fluid dynamic Finite element method

Production and characterization of high porosity porous Fe?Cr?C alloys by the space holder leaching technique

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International Journal of Minerals,Metallurgy and Materials 2016年第7期23卷 793-798页

作者： Da-rong Tian yu-hua Pang Liang yu Li sun School of Metallurgical Engineering Xi'an University of Architecture and TechnologyXi'an 710055China Research Center of Metallurgical Engineering and Technology of Shaanxi Province Xi'an 710055China AVIC Xi'an Aircraft Industry(Group)Company Ltd. Xi'an 710000China

Spherical carbamide particles were employed to produce porous Fe–Cr–C alloy with high porosity and large aperture via the space-holder leaching technique. A series of porous samples were prepared by regulating the processing parameters, which included the carbamide content and the compaction pressure. The pore characteristics and compression properties of the produced samples were investigated. The samples were characterized by scanning electron microscopy, image analysis, and compression tests. The results showed that the macro-porosity and the mean pore size were in the ranges 40.4%–82.4% and 0.6–1.5 mm, respectively. The compressive strength varied between 25.38 MPa and 127.9 MPa, and was observed to decrease with increasing total porosity.

关键词： porous metal powder metallurgy cellular manufacturing porosity compressive strength

Efficient video downscaling transcoder from MPEG-2 to H.264

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第4期9卷 457-463页

作者： Xiang-wen WANG Jun sun Rong XIE Song-yu yu Shanghai Key Lab. of Digital Media Processing ＆ Transmissions Institute of lmage Communication ＆ Information Processing Shanghai Jiao Tong University Shanghai 200240 China

The new H.264 video coding standard achieves significantly higher compression performance than MPEG-2. As the MPEG-2 is popular in digital TV, DVD, etc., bandwidth or memory space can be saved by transcoding those streams into H.264 in these applications. Unfortunately, the huge complexity keeps transcoding from being widely used in practical applications. This paper proposes an efficient transcoding architecture with a smart downscaling decoder and a fast mode decision algorithm. Using the proposed architecture, huge buffering memory space is saved and the transcoding complexity is reduced. Performance of the proposed fast mode decision algorithm is validated by experiments.

关键词： Video transcoding Mode decision Edge direction analysis

Landscape pattern and its effect on ecosystem functions in Seoul Metropolitan area:Urban ecology on distribution of the naturalized plant species

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Journal of Environmental Sciences 2003年第2期15卷 199-204页

作者： sun-Kee Hong In-Ju Song hyun-Ok Kim Eung-Kyong Lee Environmental Planning Institute Seoul National UniversitySeoul Development InstituteTechnical University BerlinEnvironmental Planning Institute Seoul National University Seoul 151-742 Korea Seoul 100-250 KoreaGermanySeoul 151-742 Korea

During land transformation process in the human history, naturalized plants were introduced to several land use patterns by the different ways of plant itself. Including some naturalized plants that had been contribute to land restoration, many naturalized plants have been invaded to original habitat or landscape for native plants. Once the plants were colonized, they extend their area and population size. Urban developed areas often give an important role of source habitat for naturalized plants and expanding their population size. In recent, this situation is appearing as one of environmental problems about the urban landscape management controlling the naturalized plants that invaded in the developed area and conserving the native vegetation. This paper is focusing on relationships between distribution of habitat of naturalized plants and landscape patch in urban area in Seoul. Gangdong-Gu, one of the administrative areas in Seoul was selected for this study. We examined the recent land use change using LANDSAT TM data and spreading of the representative naturalized plants (Robinia pseudoacacia and Eupatorium rugosum) by Seoul Biotope Mapping Project and field survey in 1999. As a result, these two species were often occurred in the same habitat and distributed in forest edge disturbed by man. Their distribution patterns were related to landscape indices (patch size and shape) in the forest edge.

关键词： biotope mapping ecosystem management human impact landscape pattern naturalized plants urban ecology