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Chinese Medical Journal 2022年第22期135卷 2767-2769页

作者： Boya Li Xiongfeng Zeng Deyi Luo Yucheng Ma Hong Li Kunjie Wang Department of Urology Institute of Urology(Laboratory of Reconstructive Urology)West China HospitalSichuan UniversityChengduSichuan 610041China

To the Editor:As one of the most powerful tools for urologists,ureteral stents are often used in diseases such as calculi,obstruction,ureteral injury,and kidney transplantation and are removed after 3 days to 4 weeks with a visualization instrument.Initially,rigid cystoscopy(RC)was most often used for stent removal,but due to its inflexibility and large diameter,RC often results in pain and potential damage to patients like hematuria,pain,and lower urinary tract symptoms,especially to men.

关键词： urinary rigid diseases

Failures in emergency management of pediatric airway foreign bodies by rigid bronchoscopy:we have yet to complete our learning

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World Journal of Pediatric Surgery 2022年第2期5卷 29-33页

作者： Mohammad Ashkan Moslehi Pediatric Interventional Pulmonology Division Medical SchoolShiraz University of Medical SciencesShirazIran

Background Several children are affected by airway foreign body aspiration(FBA)resulting from life-threatening conditions.Choking has been considered the major symptom and is defined as airway blockage by a foreign body(FB),leading to marked morbidity or mortality.This retrospective study indicates the possibility of misdiagnosis or rigid bronchoscope(RB)failure,which is the standard gold method for extracting FB in the airway.Methods Six children with airway FBA who failed treatment using RB between 2018 and 2019 were retrospectively studied.The inclusion criterion was a history of failure to extract FB using RB followed by flexible fiberoptic bronchoscopy(FFB).Results In the present study,among 63 patients who had undergone rigid bronchoscopy,airway FBs were successfully removed in 57(90.48%).rigid bronchoscopy failed in 6(9.52%)patients.The age of cases at the time of bronchoscopy ranged from 11 months to 13 years.FFB was performed to extract missing or remaining FBs and was done successfully in all patients.The patients made an uneventful recovery following FB extraction using the FFB method.Conclusions It is not easy to diagnose and treat airway FB in children.rigid bronchoscopy has been approved as a method to manage airway FB,but a negative bronchoscopy result must usually be interpreted carefully.FFB is applicable as a proper and relatively safe diagnostic and therapeutic tool in managing airway FBs among the pediatric population,especially in cases where rigid bronchoscopy was performed but missed or failed to extract the FB.

关键词： airway rigid removed

rigid reflections and Kac-Moody algebras

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Science China Mathematics 2019年第7期62卷 1317-1330页

作者： Kyu-Hwan Lee Kyungyong Lee Department of Mathematics University of Connecticut Storrs CT 06269 USA Department of Mathematics University of Nebraska-Lincoln Lincoln NE 68588 USA Korea Institute for Advanced Study Seoul 02455 Republic of Korea

Given any Coxeter group, we define rigid reflections and rigid roots using non-self-intersecting curves on a Riemann surface with labeled curves. When the Coxeter group arises from an acyclic quiver, they are related to the rigid representations of the quiver. For a family of rank 3 Coxeter groups, we show that there is a surjective map from the set of reduced positive roots of a rank 2 Kac-Moody algebra onto the set of rigid reflections. We conjecture that this map is bijective.

关键词： Coxeter groups rigid reflections rigid roots non-self-crossing curves Kac-Moody algebras

Multidimensional optical tweezers synthetized by rigid-body emulated structured light

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Photonics Research 2023年第9期11卷 1524-1534页

作者： LIUHAO ZHU YUPING TAI HEHE LI HUAJIE HU XINZHONG LI YANGJIAN CAI YIJIE SHEN School of Physics and Engineering Henan University of Science and TechnologyLuoyang 471023China State Key Laboratory of Transient Optics and Photonics Xi’an Institute of Optics and Precision MechanicsChinese Academy of SciencesXi’an 710119China Shandong Provincial Engineering and Technical Center of Light Manipulations and Shandong Provincial Key Laboratory of Optics and Photonic Device School of Physics and ElectronicsShandong Normal UniversityJinan 250014China Joint Research Center of Light Manipulation Science and Photonic Integrated Chip of East China Normal University and Shandong Normal University East China Normal UniversityShanghai 200241China Optoelectronics Research Centre University of SouthamptonSouthampton SO171BJUK Centre for Disruptive Photonic Technologies School of Physical and Mathematical Sciences and The Photonics InstituteNanyang Technological UniversitySingapore 637378Singapore

Structured light with more extended degrees of freedom(DoFs)and in higher dimensions is increasingly gaining traction and leading to breakthroughs such as super-resolution imaging,larger-capacity communication,and ultraprecise optical trapping or tweezers.More DoFs for manipulating an object can access more maneuvers and radically increase maneuvering precision,which is of significance in biology and related microscopic detection.However,manipulating particles beyond three-dimensional(3D)spatial manipulation by using current all-optical tweezers technology remains difficult.To overcome this limitation,we theoretically and experimentally present six-dimensional(6D)structured optical tweezers based on tailoring structured light emulating rigid-body mechanics.Our method facilitates the evaluation of the methodology of rigid-body mechanics to synthesize six independent DoFs in a structured optical trapping system,akin to six-axis rigid-body manipulation,including surge,sway,heave,roll,pitch,and yaw.In contrast to previous 3D optical tweezers,our 6D structured optical tweezers significantly improved the flexibility of the path design of complex trajectories,thereby laying the foundation for next-generation functional optical manipulation,assembly,and micromechanics.

关键词： rigid trapping breakthrough

Lattice Boltzmann method for simulating flows in open-channel with partial emergent rigid vegetation cover

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Journal of Hydrodynamics 2019年第4期31卷 717-724页

作者： Zhong-hua Yang Feng-peng Bai Wen-xin Huai Cheng-guang Li State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China Changjiang Water Resources Protection Institute Wuhan 430051 China Shandong Provincial Key Laboratory of Water Resources and Water Environment Water Resources Research Institute of Shandong Province Jinan 250013 China

Flows in open-channel with partial emergent rigid vegetation cover are simulated using the lattice Boltzmann method (LBM) described by the 2-D nonlinear shallow water equations. The effect of vegetation is represented with the vegetation roughness coefficient, which is related to the vegetation density, diameter of the vegetation elements and drag coefficient. The model is verified by three numerical tests: flow in a 180° curved open channel with partial vegetation cover at the outer bank, flow in a rectangular channel with a finite patch of vegetation and flow in a rectangular channel with a vegetated bank. Numerical results are compared with the experimental data, and the good agreement proved that the presented model can model the vegetated channel flows correctly.

关键词： Open-channel flow rigid vegetation lattice Boltzmann method (LBM) shallow water equations vegetation roughness coefficient

Dynamic analysis of spatial parallel manipulator with rigid and flexible couplings

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Journal of Central South University 2017年第4期24卷 840-853页

作者：刘善增戴建生沈刚李艾民曹国华冯世哲孟德远 School of Mechatronic Engineering China University of Mining and Technology King's College University of London

The dynamics of spatial parallel manipulator with rigid and flexible links is explored. Firstly, a spatial beam element model for finite element analysis is established. Then, the differential equation of motion of beam element is derived based on finite element method. The kinematic constraints of parallel manipulator with rigid and flexible links are obtained by analyzing the motive parameters of moving platform and the relationships of movements of kinematic chains, and the overall kinetic equation of the parallel mechanism with rigid and flexible links is derived by assembling the differential equations of motion of components. On the basis of abovementioned analyses, the dynamic mechanical analysis of the spatial parallel manipulator with rigid and flexible links is conducted. After obtaining the method for force analysis and expressions for the calculation of dynamic stress of flexible components, the dynamic analysis and simulation of spatial parallel manipulator with rigid and flexible links is performed. The result shows that because of the elastic deformation of flexible components in the parallel mechanism with rigid and flexible links, the force on each component in the mechanism fluctuates sharply, and the change of normal stress at the root of drive components is also remarkable. This study provides references for further studies on the dynamic characteristics of parallel mechanisms with rigid and flexible links and for the optimization of the design of the mechanism.

关键词： rigid and flexible couplings parallel mechanism finite element force analysis dynamic stress

Aerodynamic characteristics of rigid coaxial rotor by wind tunnel test and numerical calculation

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Chinese Journal of Aeronautics 2019年第3期32卷 568-576页

作者： Jinghui DENG Feng FAN Ping'an LIU Shuilin HUANG Yongfeng LIN National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics China Helicopter Research and Development Institute

Focusing on aerodynamic characteristics of rigid coaxial rotor of a high-speed helicopter in hover and forward flight, a wind tunnel test is conducted in the 8 m ? 6 m low-speed straightflow wind tunnel of China Aerodynamics Research and Development Center. In the experiment,a 4 m diameter composite model rigid coaxial rotor is designed and manufactured, and firstorder flapping frequency ratio of the blade is 1.796 to ensure sufficient stiffness at the blade root.Rotor aerodynamic performance is measured under hovering and high advance ratio conditions.Also, the numerical method is used to calculate aerodynamic characteristics in typical states of the rigid coaxial rotor for analysis purpose. The rotor lift-drag ratio and lateral lift offset in the experiment are emphatically analyzed for the rigid coaxial rotor. The results indicate that in forward flight condition, the rotor lift-drag ratio first increases and then decreases with the increment of advance ratio and lift offset. When advance ratio remains constant, with the increment of lift offset, the lift-drag ratio of rigid coaxial rotor first increases and then decreases.

关键词： Aerodynamic characteristics High-speed helicopter Lateral lift offset rigid coaxial rotor Wind tunnel test

CR-Morph: Controllable rigid Morphing for 2D Animation

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Journal of Computer Science & Technology 2019年第5期34卷 1109-1122页

作者： Wen-Wu Yang Jing Hua Kun-Yang Yao School of Computer and Information Engineering Zhejiang Gongshang UniversityHangzhou 310012China Department of Computer Science Wayne State UniversityMichigan 48202U.S.A.

This paper presents a rigidity-preserving morphing technique that blends a pair of 2D shapes in a controllable manner. The morphing is controllable in two aspects: 1) motion dynamics in the interpolation sequences can be effectively enhanced through an intuitive skeleton control and 2) not only the boundaries but also the interior features of the source and target shapes are precisely aligned during the morphing. We introduce a new compatible triangulation algorithm to decompose the source and target shapes into isomorphic triangles. Moreover, a robust and motion-controllable rigiditypreserving transformation scheme is proposed to blend the compatible triangulations, ultimately leading to a morphing sequence which is appearance-preserving and with the desired motion dynamics. Our approach constitutes a powerful and easy-to-use morphing tool for two-dimensional animation. We demonstrate its versatility, effectiveness and visual accuracy through a variety of examples and comparisons to prior work.

关键词： compatible triangulation disc-based interpolation rigid morphing skeleton-based dynamics

Structures and physical properties of rigid polyurethane foams with water as the sole blowing agent

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Science China Chemistry 2006年第4期49卷 363-370页

作者： LI Xiaobin1,2, CAO Hongbin1 & ZHANG Yi1 1. Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100080, China 2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China Institute of Process Engineering Chinese Academy of Sciences Beijing China Graduate School of the Chinese Academy of Sciences Beijing China

rigid polyurethane foams blown by varying water level were prepared in this study. The structures and physical properties of rigid polyurethane foams blown by water were measured with FT-IR, universal testing machine (Instron3365), scanning electron microscope (SEM) and differential scanning calorimeter (DSC). The results show that polyurea and polybiuret were the typical charac- teristics, and the cream time and gel time were shorter for the fully water blown rigid foams than that for the fully cyclopentane blown foams. The density of foam samples decreased from 45.0 kg/m3 to 27.4 kg/m3 with the increase of water level from 3 pph to 7 pph. Compressive strength exhibited the similar behavior with density. The average cell size of foam samples ranged from 241 μm to 356 μm with the increase of water level from 3 pph to 7 pph, respectively. At the same time, poorer dimen- sional stability was encountered with the increase of average cell size due to fast diffusion rate of CO2 out of the foam. The results of thermal analysis show that the glass transition temperature (Tg) shifted to a higher temperature with the increase of isocyanate level when more water was used as chemical blowing agent.

关键词： polyether polyol, polyurethane rigid foam, compressive strength, dimensional stability, cell size, glass transition temperature.

Seismic responses of the steel-strip reinforced soil retaining wall with full-height rigid facing from shaking table test

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Journal of Mountain Science 2018年第5期15卷 1137-1152页

作者： CAO Li-cong FU Xiao WANG Zhi-jia ZHOU Yong-yi LIU Fei-cheng ZHANG Jian-jing Key Laboratory of Transportation Tunnel Engineering Ministry of Education School of Civil Engineering Southwest Jiaotong University Department of Geotechnical Engineering School of Civil Engineering Southwest Jiaotong University Department of Civil Engineering and Architecture Hainan University

To investigate the seismic response of the steel-strip reinforced soil retaining wall with fullheight rigid facing in terms of the acceleration in the backfill, dynamic earth pressure in the backfill, the displacements on the facing and the dynamic reinforcement strain distribution under different peak acceleration, a large 1-g shaking table test was performed on a reduced-scale reinforced-earth retaining wall model. It was observed that the acceleration response in non-strip region is greater than that in potential fracture region which is similar with the stability region under small earthquake,while the acceleration response in potential fracture region is greater than that in stability region in middle-upper of the wall under moderately strong earthquakes. The potential failure model of the rigid wall is rotating around the wall toe. It also was discovered that the Fourier spectra produced by the inputting white noises after seismic wave presents double peaks, rather than original single peak, and the frequency of the second peak trends to increase with increasing the PGA(peak ground amplitude) of the excitation which is greater than 0.4 g. Additionally,the non-liner distribution of strip strain along the strips was observed, and the distribution trend was not constant in different row. Soil pressure peak value in stability region is larger than that in potential fracture region. The wall was effective under 0.1 g-0.3 g seismic wave according to the analyses of the facing displacement and relative density. Also, it was discovered that the potential failure surface is corresponds to that in design code, but the area is larger. The results from the study can provide guidance for a more rational design of reinforced earth retaining walls with full-height rigid facing in the earthquake zone.

关键词： Reinforced soil retaining walls Potentialfailure surface Full-height rigid facing Steel strip Seismic behaviors 1-g shaking table test