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Computational Visual Media 2015年第4期1卷 279-289页

作者： peng song School of Computer Science and Technology University of Science and Technology of China

Surface registration brings multiple scans into a common coordinate system by aligning their overlapping components. This can be achieved by finding a few pairs of matched points on different scans using local shape descriptors and employing the matches to compute transformations to produce the alignment. By defining a unique local reference frame(LRF) and attaching an LRF to shape descriptors,the transformation can be computed using only one match based on aligning the LRFs. This paper proposes a local voxelizer descriptor,and the key ideas are to define a unique LRF using the support around a basis point,to perform voxelization for the local shape within a cubical volume aligned with the LRF,and to concatenate local features extracted from each voxel to construct the descriptor. An automatic rigid registration approach is given based on the local voxelizer and an expanding strategy that merges descriptor representations of aligned scans. Experiments show that our registration approach allows the acquisition of 3D models of various objects,and that the local voxelizer is robust to mesh noise and varying mesh resolution,in comparison to two state-of-the-art shape descriptors.

关键词： shape descriptor surface registration scan alignment 3D reconstruction

Floquet analysis of fundamental,subharmonic and detuned secondary instabilities of Grtler vortices

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Science China(Physics,Mechanics & Astronomy) 2014年第3期57卷 555-561页

作者： REN Jie fu song School of Aerospace Engineering Tsinghua University

Nonlinear parabolized stability equations are employed in this work to investigate the nonlinear development of the G6rtler insta- bility up to the saturation stage. The perturbed boundary layer is highly inflectional both in the normalwise and spanwise directions and receptive to the secondary instabilities. The Floquet theory is applied to solve the fundamental, subharmonic and detuned secondary instabilities. With the Gortler-vortices-distorted base flow, two classes of secondary disturbances, i.e. odd modes and even modes, are identified according to the eigenfunctions of the disturbances. These modes may result in different patterns in the late stages of the transition process. Li and Malik [ 1 ] have shown the sinuous and varicose types of breakdown originating from the odd and even modes. The current study focuses on the four most amplified modes termed the even modes I ＆ Ⅱ and odd modes I ＆ lI. Odd mode II was missing in the work of Li and Malik [1] probably due to their inviscid simplifeation. The detuned modes are confirmed to be less amplifed than the fundamental （for the odd mode I） and subharmonic modes （for even modes I ＆ II and the odd mode II）.

关键词： Goirtler vortices secondary instability Floquet theory

Analysis of flow structures in supersonic plane mixing layers using the POD method

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Science China(Physics,Mechanics & Astronomy) 2008年第5期51卷 541-558页

作者： YANG Qin fu song School of Aerospace Tsinghua UniversityBeijing 100084China

The proper orthogonal decomposition(POD) method was applied to analyzing the database obtained from the direct numerical simulation(DNS) of supersonic plane mixing *** effect of different forms of the inner products in the POD method was *** was observed that the mean flow contributes to a predominant part of the total flow energy,and the energy spectrum of the turbulence fluctuations covers a wide range of POD *** patterns of leading(high energy) POD modes reveal that the flow structures exhibit spanwise counter rotating rolls,as well as oblique *** flow patterns are insensitive to the velocity of the *** the convective Mach number increases,the energy spectrum be-comes wider,the leading POD modes contain more complicated structures,and the flow becomes more chaotic.

关键词： coherent structure compressible mixing layer POD low-dimensional model

Modelling flow transition in a hypersonic boundary layer with Reynolds-averaged Navier-Stokes approach

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Science China(Physics,Mechanics & Astronomy) 2009年第5期52卷 768-774页

作者： WANG Liang fu song School of Aerospace Tsinghua UniversityBeijing 100084China

Based on Reynolds-averaged Navier-Stokes approach,a laminar-turbulence transition model is proposed in this study that takes into account the effects of different instability modes associated with the variations in Mach numbers of compressible boundary layer *** model is based on k-ω-γ three-equation eddy-viscosity concept with k representing the fluctuating kinetic energy,ωthe specific dissipation rate and the intermittency factorγ.The particular features of the model are that:1)k includes the non-turbulent,as well as turbulent fluctuations;2)a transport equation for the intermittency factorγis proposed here with a source term set to trigger the transition onset;3)through the introduction of a new length scale normal to wall,the present model employs the local variables only avoiding the use of the integral parameters,like the boundary layer thicknessδ,which are often cost-ineffective with the modern CFD(Computational Fluid Dynamics)methods;4)in the fully turbulent region,the model retreats to the well-known k-ωSST(Shear Stress Transport)*** model is validated with a number of available experiments on boundary layer transitions including the incompressible,supersonic and hypersonic flows past flat plates,straight/flared cones at zero incidences,*** is demonstrated that the present model can be successfully applied to the engineering calculations of a variety of aerodynamic flow transition.

关键词： hypersonic boundary-layer transition turbulence model intermittency factor

Research of the rapid pressure-strain correlation model in the rapid distortion limit

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Science China(Physics,Mechanics & Astronomy) 2008年第9期51卷 1380-1389页

作者： HUANG SiYuan fu song Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China

Even though a number of rapid pressure-strain models have been suggested and successfully tested for different flow situations by various authors,the model proposals still exhibit some apparent deficiencies when subjected to the flows with rapid distortion. From Mansour's relatively straightforward rapid distortion analysis,if an initially anisotropic flow undergoes a purely rapid rotation,the anisotropy measures will exhibit the behavior of the damped oscillations. Within the current framework of modeling the rapid pressure-strain correlation,i.e.,the models based on the assumption that the M-tensor for the rapid pressure-strain term is expand-able in the Reynolds-stress anisotropy tensor alone,all the model predictions fail to give the damped oscillations in the turbulence anisotropy. In the case of initially isotropic turbulence subjected to rapid distortion,Sj?gren and Johansson showed that all the existing rapid pressure-strain models would deliver the identical path in the anisotropy-invariant map for both homogeneous plane strain and shear flows. The rapid distortion analysis shows two distinct curves reflecting different flow physics. In this work,we try to present a possible way to create a system that can overcome these deficiencies with the aid of the rapid distortion theory (RDT).

关键词： Reynolds-Stress turbulence Model rapid pressure-strain correlation rapid distortion theory

缬沙坦与氨氯地平治疗原发性高血压的比较研究

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现代药物与临床 2016年第8期31卷 1177-1180页

作者：彭夫松杨磊磊孙剑笠张利利魏霄瑾北京市垂杨柳医院老年病科北京100022

目的比较缬沙坦和氨氯地平治疗原发性高血压的临床疗效。方法选取2012年12月—2015年12北京市垂杨柳医院老年病科收治的原发性高血压患者121例,随机分为缬沙坦组(n=60)和氨氯地平组(n=61)。缬沙坦组患者口服缬沙坦胶囊,1粒/次,1次/d。... 详细信息

目的比较缬沙坦和氨氯地平治疗原发性高血压的临床疗效。方法选取2012年12月—2015年12北京市垂杨柳医院老年病科收治的原发性高血压患者121例,随机分为缬沙坦组(n=60)和氨氯地平组(n=61)。缬沙坦组患者口服缬沙坦胶囊,1粒/次,1次/d。氨氯地平组患者口服苯磺酸氨氯地平片,1片/次,1次/d。两组均连续治疗12周。观察两组的临床疗效,同时比较两组治疗前后收缩压、舒张压、心率、总胆固醇(TC)、三酯甘油(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、脂联素(APN)、一氧化氮(NO)、内皮素(ET)的变化情况。结果氨氯地平组和缬沙坦组的总有效率分别为78.69%、80.00%,两组比较差异无统计学意义。治疗后,两组患者收缩压、舒张压、心率、ET均显著降低,APN、NO显著升高,同组治疗前后差异有统计学意义(P<0.05)。治疗后,缬沙坦组心率低于氨氯地平组,APN水平高于氨氯地平组,两组比较差异具有统计学意义(P<0.05)。结论缬沙坦和氨氯地平治疗原发性高血压均具有较好的临床疗效,缬沙坦可提高患者血浆脂联素水平,改善血管内皮功能,氨氯地平对脂联素水平无显著影响。

关键词：缬沙坦胶囊苯磺酸氨氯地平片原发性高血压脂联素

MoS_(2)Lubricate‑Toughened MXene/ANF Composites for Multifunctional Electromagnetic Interference Shielding

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Nano-Micro Letters 2025年第2期17卷 358-371页

作者： Jiaen Wang Wei Ming Longfu Chen Tianliang song Moxi Yele Hao Zhang Long Yang Gegen Sarula Benliang Liang Luting Yan Guangsheng Wang School of Physical Science and Engineering Beijing Jiaotong UniversityBeijing 100044People’s Republic of China Key Laboratory of Bio‑Inspired Smart Interfacial Science and Technology of Ministry of Education School of ChemistryBeihang UniversityBeijing 100191People’s Republic of China

The design and fabrication of high toughness electromagnetic interference(EMI)shielding composite films with diminished reflection are an imperative task to solve electromagnetic pollution *** MXene/ANF(aramid nanofibers)–MoS_(2)composite films with nacre-like layered structure here are fabricated after the introduction of MoS_(2)into binary MXene/ANF composite *** introduction of MoS_(2)fulfills an impressive“kill three birds with one stone”improvement effect:lubrication toughening mechanical performance,reduction in secondary reflection pollution of electromagnetic wave,and improvement in the performance of photothermal *** the introduction of MoS_(2)into binary MXene/ANF(mass ratio of 50:50),the strain to failure and tensile strength increase from 22.1±1.7%and 105.7±6.4 MPa and to 25.8±0.7%and 167.3±9.1 MPa,*** toughness elevates from 13.0±4.1 to 26.3±0.8 MJ m^(−3)(~102.3%)*** the reflection shielding effectiveness(SE_(R))of MXene/ANF(mass ratio of 50:50)decreases~10.8%.EMI shielding effectiveness(EMI SE)elevates to 41.0 dB(8.2–12.4 GHz);After the introduction of MoS_(2)into binary MXene/ANF(mass ratio of 60:40),the strain to failure increases from 18.3±1.9%to 28.1±0.7%(~53.5%),the SE_(R)decreases~22.2%,and the corresponding EMI SE is 43.9 *** MoS_(2)also leads to a more efficient photothermal conversion performance(~45 to~55℃).Additionally,MXene/ANF–MoS_(2)composite films exhibit excellent electric heating performance,quick temperature elevation(15 s),excellent cycle stability(2,2.5,and 3 V),and long-term stability(2520 s).Combining with excellent mechanical performance with high MXene content,electric heating performance,and photothermal conversion performance,EMI shielding ternary MXene/ANF–MoS_(2)composite films could be applied in many industrial *** work broadens how to achieve a balance between mechanical properties and versatility of composites in the case of high-function fillers.

关键词： MXene-MoS_(2) Lubrication toughening EMI shielding Photothermal conversion Electric heating performance

Competition of the multiple Grtler modes in hypersonic boundary layer flows

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Science China(Physics,Mechanics & Astronomy) 2014年第6期57卷 1178-1193页

作者： REN Jie fu song School of Aerospace Engineering Tsinghua University

Competition of multiple Gortler modes in hypersonic boundary layer flows are investigated with the local and marching methods. The wall-layer mode （mode W） and the trapped-layer mode （mode T） both occur in the compressible boundary layer where there exists a temperature adjustment layer near the upper edge. The mode T has the largest growth rate at a lower Gortler number while the mode W dominates at larger G/Srtler numbers. These two modes are both responsible for the flow transition in the hypersonic flows especially when Gortler number is in the high value range in which the crossover of these two modes takes place. Such high Gortler numbers are virtually far beyond the neutral regime. The nonparallel base flows, therefore, cease to influence the stability behavior of the Gortler modes. The effects of the Mach number on the multiple Gortler modes are studied within a chosen Mach number of 0.95, 2, 4 and 6. When the flow Mach number is sufficiently large, e.g., Ma ≥4, the growth rate crossover of the mode T and mode W occurs both in the conventional G-β map as well as on the route downstream for a fixed wavelength disturbance. Four particular regions （Region T, T-W, W-T and W） around the crossover point are highlighted with the marching analysis and the result matches that of the local analysis. The initial disturbance of a normal mode maintains the shape in its corresponding dominating region while a shape-transformation occurs outside this region.

关键词： Gortler vortices linear stability theory multiple modes local analysis marching analysis

Coexistence of multiple genotypes of porcine epidemic diarrhea virus with novel mutant S genes in the Hubei Province of Chinain 2016

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Virologica Sinica 2017年第4期32卷 298-306页

作者： Zhe Zeng Ting-Ting Li Xin Jin fu-Hu peng Nian-Hua song Gui-Qing peng Xing-Yi Ge State Key Laboratory of Agricultural Microbiology College of Veterinary MedicineHuazhongAgricultural UniversityWuhan 430070China Hubei Animal Disease Prevention and Control Center Wuhan 430070China College of Biology Hunan UniversityChangsha 410082China

The emergence of highly virulent porcine epidemic diarrhea virus(PEDV) variants in China caused huge economic losses in 2010. Since then, large-scale sporadic outbreaks of PED caused by PEDV variants have occasionally occurred in China. However, the molecular diversity and epidemiology of PEDV in different provinces has not been completely understood. To determine the molecular diversity of PEDV in the Hubei Province of China, we collected 172 PED samples from 34 farms across the province in 2016 and performed reverse transcription polymerase chain reaction(RTPCR)by targeting the nucleocapsid(N) gene. Seventy-four samples were found to be *** further characterized the complete spike(S) glycoprotein genes from the positive samples and found 21 different S genes with amino acid mutations. The PEDV isolates here presented most of the genotypes which were found previously in field isolates in East and SouthEast Asia, North America, and Europe. Besides the typical Genotypes Ⅰ and Ⅱ, the INDEX groups were also found. Importantly, 58 new amino acids mutant sites in the S genes, including 44 sites in S1 and 14 sites in S2, were first described. Our results revealed that the S genes of PEDV showed variation and that diverse genotypes of PEDV coexisted and were responsible for the PED outbreaks in Hubei in 2016. This work highlighted the complexity of the epidemiology of PEDV and emphasized the need for reassessing the efficacy of classic PEDV vaccines against emerging variant strains and developing new vaccines to facilitate the prevention and control of PEDV in fields.

关键词： porcine epidemic diarrhea virus (PEDV) coronavirus spike genetic variation