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Influence of Blade Outlet Angle on Inner Flow Field of Centrifugal Pump Transporting Salt Aqueous Solution

Chinese Journal of Mechanical Engineering 2009年第6期22卷 912-917页

作者： YANG Minguan kang Can dong Xiang liu dong School of Energy and Power Engineering Jiangsu University Zhenjiang 212013 China

During transportation of salt aqueous solutions with centrifugal pump, crystallization phenomenon is frequently encountered. For this kind of two-phase flow, it is difficult to be accurately modeled since there are various medium properties and phase change characteristics. In view of experiment, several problems are hampering the implementation of precise measurement. Influences of blade outlet angle and medium temperature on crystallization rate were studied. Sodium sulfate solution was applied to simulate practical fluid in chemical industry. Particle image velocimetry（PIV） was employed to measure velocity distributions in rotating impeller. Crystallization processes in three impellers with different blade outlet angles were investigated. Relations among crystallization and flow parameters such as temperature and velocity were obtained. With the same blade wrap angle, when blade outlet angle is larger, diffusion of single flow passage gets stronger, relative velocity at blade outlet decreases and large scale vortex tends to appear near the blade working surface. For the impact of volume effect of particle phase on fluid viscosity, both liquid and solid phase velocities decrease with continual forming and growing of crystal particles. Velocity of solid phase is greater than that of liquid phase and its direction leans more closely to blade working surface. Solid particles tend to move towards blade working surface, as is more obvious in the impeller with large blade outlet angle. Therefore, collision between solid particles with stem part of blade working surface is more intensive in impeller with large blade outlet angle. Concerning transportation of salt aqueous solution, accurate PIV measurement is conducted in centrifugal impellers with different blade outlet angles. The results are useful and instructive in relevant engineering design and operation.

关键词： centrifugal pump flow with crystallization blade outlet angle particle image velocimetry(PIV)

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ROP11 GTPase is a Negative Regulator of Multiple ABA Responses in Arabidopsis

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Journal of Integrative Plant Biology 2012年第3期54卷 169-179页

作者： Zixing Li Jun kang Ning Sui dong liu MOE Key Laboratory of Bioinformatics School of Life Sciences Tsinghua University Beijing 100084 China

The phytohormone abscisic acid （ABA） plays crucial roles in plant development and plant responses to environmental stresses. Although ABA receptors and a minimal set of core molecular components have recently been discovered, understanding of the ABA signaling pathway is still far from complete. In this work, we characterized the function of ROP11, a member of the plant-specific ROP small GTPases family, in the ABA signaling process. ROP11 is preferentially expressed in guard cells in all plant organs with stomata. Expression of a constitutively active ROP11 （CA-ROP11） suppresses ABA-mediated responses, whereas reduced expression of ROP11 or expression of its dominant-negative form （DN-ROP11） causes the opposite phenotypes. The affected ABA-mediated responses by ROP11 include seed germination, seedling growth, stomatal closure, induction of ABA-responsive genes, as well as plant response to drought stress. Furthermore, we showed that ROP11 and its closest-related family member, ROP10, act in parallel in mediating these responses. ABA treatment does not affect ROP11 transcription and protein abundance; however, it causes the accumulation of CA-ROP11 in the nucleus. These results demonstrated that ROP11 is a negative regulator of multiple ABA responses in Arabidopsis.

关键词： ROP11 GTPase ABA responses negative regulator rop10rop1 double mutant Arabidopsis.

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Strongly screened electron capture rates of chromium isotopes in presupernova evolution

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Research in Astronomy and Astrophysics 2017年第10期17卷 91-96页

作者： Jing-Jing liu Qiu-He Peng Liang-Huan Hao Xiao-Ping kang dong-Mei liu College of Marine Science and Technology Hainan Tropical Ocean University Department of Astronomy Nanjing University

Taking into account the effect of electron screening on electron energy and electron capture threshold energy, by using the method of Shell-Model Monte Carlo and random phase approximation theory, we investigate the capture rates of chromium isotopes with strong electron screening according to the linear response theory screening model. Strong screening rates can decrease by about 40.43% （e.g., for 6Cr at T9 = 3.44, Ye = 0.43）. Our conclusions may be helpful to researches on supernova explosions and related numerical simulation methods.

关键词： nuclear reactions -- electron capture -- supernovae

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Experimental Study on the Effect of Increased Downstroke Duration for an FWAV with Morphing-coupled Wing Flapping Configuration

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Journal of Bionic Engineering 2024年第1期21卷 192-208页

作者： Ang Chen Bifeng Song ZhiheWang kang liu dong Xue Xiaojun Yang School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China Harbin Institute of Technology Shenzhen 518055China

This paper is based on a previously developed bio-inspired Flapping Wing Aerial Vehicle(FWAV),RoboFalcon,which can fly with a morphing-coupled flapping *** this paper,a simple flapping stroke control system based on Hall effect sensors is designed and applied,which is capable of assigning different up-and down-stroke speeds for the RoboFalcon platform to achieve an adjustable downstroke *** aerodynamic and power characteristics of the morphing-coupled flapping pattern and the conventional flapping pattern with varying downstroke ratios are measured through a wind tunnel experiment,and the corresponding aerodynamic models are developed and analyzed by the nonlinear least squares *** relatively low power consumption of the slow-downstroke mode of this vehicle is verified through outdoor flight *** results of wind tunnel experiments and flight tests indicate that increased downstroke duration can improve aerodynamic and power performance for the RoboFalcon platform.

关键词： Flapping wing aerial vehicle(FWAV) Downstroke ratio Bio-inspired design Morphing-coupled flapping

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Effects of dynamical spanwise retraction and stretch on flapping-wing forward flights

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Chinese Journal of Aeronautics 2024年第4期37卷 181-202页

作者： kang liu Bifeng SONG Ang CHEN Zhihe WANG dong XUE Wenqing YANG School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Intelligent Aircraft Research Center Chengdu Technological UniversityChengdu 610031China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518057China Harbin Institute of Technology Shenzhen 518055China

Birds and bats retract and stretch their wings dynamically during each flap in level flights, implying intriguing mechanisms for the aerodynamic performance improvement of flapping wings. A numerical investigation into the aerodynamic effects of such bio-inspired concept in forward flights has been performed based on a three-dimensional wing in plunging motion and a twosection wing in flapping motion. The currently considered Reynolds number and Strouhal number are Re=1.5×10^(5) and St=0.3, respectively. During the research, the mean angle of attack is varied in relatively wide ranges to achieve lift-thrust interconversion for the wings. The conclusive results show that dynamical spanwise retraction and stretch has induced three absolutely desirable scenarios for the oscillating wings in forward flights, namely producing more lift and consuming less power for a given thrust generation, producing more thrust and consuming less power for a given lift generation, and producing more lift and more thrust while consuming less power. Furthermore,the morphing wings have alleviated periodical aerodynamic load fluctuations compared with the non-morphing baseline. The mechanism of the aerodynamic effects of the bionic morphing mode is analyzed with the aid of field visualization. The current article is the first to reveal the absolute advantages of the bionic spanwise morphing. Hopefully, it may help comprehend the behaviors of natural fliers and provide inspirations for performance enhancement of micro artificial flappingwing vehicles.

关键词： Flapping wing Morphing wing Bionic Aerodynamics Vortex Flight

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Prevotella oris-caused meningitis and spinal canal infection:A case report

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World Journal of Clinical Cases 2023年第16期11卷 3830-3836页

作者： Wei-Wei Zhang Chao Ai Chien-Tai Mao dong-kang liu Yi Guo Department of Clinical Pharmacy Beijing Tsinghua Changgung HospitalSchool of MedicineTsinghua UniversityBeijing 102218China Department of Neurosurgery Beijing Tsinghua Changgung HospitalSchool of MedicineTsinghua UniversityBeijing 102218China

BACKGROUND Prevotella oris-induced meningitis and Prevotella oris-induced meningitis concomitant with spinal canal infection are extremely *** the best of our knowledge,only 1 case of Prevotella oris-induced central system infection has been *** is the second report on meningitis combined with spinal canal infection due to Prevotella *** SUMMARY We report a case of a 9-year-old boy suffering from meningitis and spinal canal *** patient presented to the neurosurgery department with lumbosacral pain for 1 mo and headache and vomiting for 1 *** had been treated with cephalosporin and nonsteroidal anti-inflammatory drugs for fever,otalgia and pharyngalgia in a local hospital 2 mo prior to this *** hospitalization,magnetic resonance imaging suggested meningitis and L3-S1 lumbosacral dural sac *** cerebrospinal fluid and blood cultures were negative,but the cerebrospinal fluid specimen indicated the presence of Prevotella oris by metagenomic next-generation *** cases of Prevotella oris infection were retrieved from PubMed to characterize the clinicopathological features and identify the prognostic factors and related antimicrobial treatment of infection due to Prevotella *** This report shed light on the characteristics of Prevotella oris infection and highlighted the role of metagenomic next-generation sequencing in pathogen detection.

关键词： Prevotella oris Meningitis Spinal canal infection Metagenomic next-generation sequencing Central nervous system infection Case report

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Quantitative evaluation of the contribution of underground space to urban resilience:A case study in China

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Underground Space 2024年第4期17卷 1-24页

作者： Si-Cong liu Fang-Le Peng Yong-kang Qiao Yun-Hao dong Research Center for Underground Space&Department of Geotechnical Engineering Tongji UniversityShanghai 200092China

Urban underground space(UUS)development has been acknowledged as a positive contribution to urban resilience(UR).Such contribution has been qualitatively addressed in recent years,but only quantitatively discussed in few *** evaluation methods for UR are widely used in China and around the world,but the role of underground space is barely *** paper provides a way to bridge this gap on the city scale.A UR evaluation framework was carefully constructed that covers the basic aspects and elements of *** contributions of UUS to UR were identified and integrated into the UR evaluation framework,and the measurement methods for each indicator related to UUS were determined.A case study of 19 sample cities in China were conducted using the integrated evaluation *** analysis and clustering analysis were further adopted to interpret the evaluation results,mainly with three indicators reflecting the level of UUS development,namely UUS area(m^(2)),UUS density(104 m^(2)/km^(2))and UUS area per capita(m^(2)/person).The results showed a strong correlation between UUS area and *** average proportion of UR provided by UUS in the 19 sample cities was 16.46%,while the maximum figure reached 29.20%.The sample cities were clustered into four categories based on the relationship between the proportion of UR provided by UUS,UUS area,and GDP per capita,where both high and low UUS area tend to provide less proportion of resilience than the medium UUS *** suggestions for UUS utilization were proposed to assist cities in achieving urban resilience.

关键词： Urban underground space(UUS) Urban resilience Resilience evaluation Resilient development

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Constructing high-toughness polyimide binder with robust polarity and ion-conductive mechanisms ensuring long-term operational stability of silicon-based anodes

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Journal of Energy Chemistry 2024年第6期93卷 580-591,I0014页

作者： Yongjun kang Nanxi dong Fangzhou liu Daolei Lin Bingxue liu Guofeng Tian Shengli Qi Dezhen Wu State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China ENFI R&D Institute China ENFI Engineering CorporationBeijing 100038China China Automotive Battery Research Institute Co. Ltd.Beijing 101407China Changzhou Institute of Advanced Materials Beijing University of Chemical TechnologyChangzhou 213164JiangsuChina

Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical ***,the significant volume expansion of silicon seriously hinders its utilization as a lithium-ion ***,a functionalized high-toughness polyimide(PDMI) is synthesized by copolymerizing the 4,4'-Oxydiphthalic anhydride(ODPA) with 4,4'-oxydianiline(ODA),2,3-diaminobenzoic acid(DABA),and 1,3-bis(3-aminopropyl)-tetramethyl disiloxane(DMS).The combination of rigid benzene rings and flexible oxygen groups(-O-) in the PDMI molecular chain via a rigidness/softness coupling mechanism contributes to high *** plentiful polar carboxyl(-COOH) groups establish robust bonding *** ionic transport is achieved by incorporating the flexible siloxane segment(Si-O-Si),which imparts high molecular chain motility and augments free volume holes to facilitate lithium-ion transport(9.8 × 10^(-10) cm^(2) s^(-1) vs.16 × 10^(-10) cm^(2) s~(-1)).As expected,the SiO_x@PDMI-1.5 electrode delivers brilliant long-term cycle performance with a remarkable capacity retention of 85% over 500 cycles at 1.3 A g^(-1).The well-designed functionalized polyimide also significantly enhances the electrochemical properties of Si nanoparticles ***,the assembled SiO_x@PDMI-1.5/NCM811 full cell delivers a high retention of 80% after 100 *** perspective of the binder design strategy based on polyimide modification delivers a novel path toward high-capacity electrodes for high-energy-density batteries.

关键词： Polyimide binder High toughness Robust ionic transport Silicon-based anodes Lithium-ion batteries

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Spatial heterogeneity and compositional profiles of dissolved organic matter in farmland soils across China' Mainland

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Journal of Environmental Sciences 2024年第3期137卷 593-603页

作者： Bingjun Han Liyuan Chen kang Xiao Yang liu dong Cao Lu Yu Yujun Li Shu Tao Wenxin liu Key Laboratory for Earth Surface Processes College of Urban and Environmental SciencesPeking UniversityBeijing 100871China Beijing Yanshan Earth Critical Zone National Research Station College of Resources and EnvironmentUniversity of Chinese Academy of SciencesBeijing 101408China Center for Water and Ecology State Key Joint Laboratory of Environment Simulation and Pollution ControlSchool of EnvironmentTsinghua UniversityBeijing 100084China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental ScienceChinese Academy of SciencesBeijing 100085China

Dissolved organic matter(DOM) plays an essential role in many geochemical processes,however its complexity, chemical diversity, and molecular composition are poorly understood. Soil samples were collected from 500 vegetable fields in administrative regions of China' Mainland, of which 122 were selected for further investigation. DOM properties were characterized by three-dimensional excitation-emission matrix(3D-EEM) fuorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry(FTICRMS)(field intensity is 15 Tesla). Our results indicated that the main constituents were UVA humic-like substances, humic-like substances, fulvic acid-like substances, and tyrosine-like substances. A total of 10,989 molecular formulae with a mass range of 100.04 to 799.59 Da were detected, covering the mass spectrometric information of the soil samples from 27 different regions. CHO and CHON molecules were dominant in DOM, whereas lignin, tannins,and aromatic substances served as the main components. The results of cluster analysis revealed that the soil properties in Jiangxi Province were considerably different from those in other regions. The key backgrounds of the DOM molecular characteristics in the vegetablefield soil samples across China' Mainland were provided at the molecular level, with large abundance and great variability.

关键词： Dissolved organic matter(DOM) Fourier transform ion cyclotron resonance mass(FTICR-MS) Excitation-emission matrix(EEM) Vegetable-field soils China' Mainland

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Multifunctional Sodium Gluconate Electrolyte Additive Enabling Highly Reversible Zn Anodes

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Chemical Research in Chinese Universities 2024年第4期40卷 722-729页

作者： ZHAO kang ZHAO Jianan YU Meng liu Fangming dong Yang WANG Shiwen CHENG Fangyi College of Chemistry Nankai UniversityTianjin300071P.R.China College of New Energy Zhengzhou University of Light IndustryZhengzhou450002P.R.China

Sodium gluconate(SG)is reported as an electrolyte additive for rechargeable aqueous zinc *** SG addition is proposed to modulate the nucleation overpotential and plating behaviors of Zn by forming a shielding buffer layer because of the adsorption priority and large steric hindrance effect,which contributes to limited rampant Zn^(2+)diffusion and mitigated hydrogen evolution and *** the introduction of 30 mmol/L SG in 2 mol/L ZnSO_(4)electrolyte,the Zn anode harvests a reversible cycling of 1200 h at 5 mA/cm^(2)and a high average Coulombic efficiency of Zn plating/stripping(99.6%).Full cells coupling Zn anode with V_(2)O_(5)·1.6H_(2)O or polyaniline cathode far surpass the SG additivefree batteries in terms of cycle stability and rate *** work provides an inspiration for design of a high-effective and low-cost electrolyte additive towards Zn-based energy storage devices.

关键词： Electrolyte additive Zn anode Sodium gluconate Adsorption Zn dendrite

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