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Influence of wing flexibility on the aerodynamic performance of a tethered flapping bumblebee

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Theoretical & Applied Mechanics Letters 2020年第6期10卷 382-389页

作者： Hung truong Thomas Engels Dmitry Kolomenskiy Kai Schneider Aix-Marseille Université CNRSCentrale MarseilleI2MMarseilleFrance University of Rostock Institute of BiosciencesAnimal PhysiologyRostockGermany Global Scientific Information and Computing Center Tokyo Institute of TechnologyMegurokuTokyoJapan

The sophisticated structures of flapping insect wings make it challenging to study the role of wing flexibility in insect *** this study,a mass-spring system is used to model wing structural dynamics as a thin,flexible membrane supported by a network of *** vein mechanical properties can be estimated based on their diameters and the Young's modulus of *** order to analyze the effect of wing flexibility,the Young's modulus is varied to make a comparison between two different wing models that we refer to as flexible and highly *** wing models are coupled with a pseudo-spectral code solving the incompressible Navier–Stokes equations,allowing us to investigate the influence of wing deformation on the aerodynamic efficiency of a tethered flapping *** to the bumblebee model with rigid wings,the one with flexible wings flies more efficiently,characterized by a larger lift-to-power ratio.

关键词： Insect flight Wing elasticity Mass-spring model Fluid-structure interaction Spectral method Volume penalization method

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Recent advances towards single biomolecule level understanding of protein adsorption phenomena unique to nanoscale polymer surfaces with chemical variations

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Nano Research 2020年第5期13卷 1295-1317页

作者： David H.Cho Tian Xie Johnson truong Andrew C.Stoner Jong-in Hahm Department of Chemistry Georgetown University37th&O Sts.NW.WashingtonDC 20057USA

Protein adsorption onto polymer surfaces is a very complex and ubiquitous phenomenon whose integrated process impacts essential applications in our daily lives such as food packaging materials,health devices,diagnostic tools,and medical ***,novel polymer materials with greater chemical intricacy and reduced dimensionality are used for various applications involving adsorbed proteins on their ***,the nature of protein-surface interactions to consider is becoming much more complicated than before.A large body of literature exists for protein ***,most of these investigations have focused on collectively measured,ensemble-averaged protein behaviors that occur on macroscale and chemically unvarying polymer surfaces instead of direct measurements at the single protein or sub-protein *** addition,interrogations of protein-polymer adsorption boundaries in these studies were typically carried out by indirect methods,whose insights may not be suitably applied for explaining individual protein adsorption processes occurring onto nanostructured,chemically varying polymer ***,an important gap in our knowledge still exists that needs to be systematically addressed via direct measurement means at the single protein and sub-protein *** efforts will require multifaceted experimental and theoretical approaches that can probe multilength scales of protein adsorption,while encompassing both single proteins and their collective ensemble behaviors at the length scale spanning from the nanoscopic all the way to the macroscopic *** this review,key research achievements in nanoscale protein adsorption to date will be ***,protein adsorption studies involving polymer surfaces with their defining feature dimensions and associated chemical partitions comparable to the size of individual proteins will be discussed in *** this regard,recent works bridging the crucial knowledge gap in protein adso

关键词： nanoscale protein adsorption nanoscale protein assembly protein self-assembly on polymer protein nanopatterning protein-nanosurface interaction

Pitching Moment Generation in an Insect-Mimicking Flapping-Wing System

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Journal of Bionic Engineering 2014年第1期11卷 36-51页

作者： Tri Quang truong Vu Hoang Phan Sanjay P. Sane Hoon Cheol Park Biomimetics and Intelligent Microsystem Laboratory & Artificial Muscle Research Center Konkuk University Seoul 143-70 l Korea Department of Advanced Technology Fusion Konkuk University Seoul 143-701 Korea National Centre for Biological Sciences Tata Institute of Fundamental Research Bangalore India

Unlike birds, insects lack control surfaces at the tail and hence most insects modify their wing kinematics to produce control forces or moments while flapping their wings. Change of the flapping angle range is one of the ways to modify wing kinematics, resulting in relocation of the mean Aerodynamic force Center （mean AC） and finally creating control moments. In an attempt to mimic this feature, we developed a flapping-wing system that generates a desired pitching moment during flap- ping-wing motion. The system comprises a flapping mechanism that creates a large and symmetric flapping motion in a pair of wings, a flapping angle change mechanism that modifies the flapping angle range, artificial wings, and a power source. From the measured wing kinematics, we have found that the flapping-wing system can properly modify the flapping angle ranges. The measured pitching moments show that the flapping-wing system generates a pitching moment in a desired direction by shifting the flapping angle range. We also demonstrated that the system can in practice change the longitudinal attitude by generating a nonzero pitching moment.

关键词： flapping-wing system pitching moment flapping angle unsteady blade element theory mean aerodynamic center,center of gravity

Effect of Wing Kinematics Modulation on Aerodynamic Force Generation in Hovering Insect-mimicking Flapping-wing Micro Air Vehicle

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Journal of Bionic Engineering 2015年第4期12卷 539-554页

作者： Hoang Vu Phan Quang Tri truong Thi Kim Loan Au Hoon Cheol Park Artificial Muscle Research Center Konkuk University Seoul 143-701 South Korea National Research Laboratory for Biomimetics and Intelligent Microsystems Konkuk University Seoul 143-701 South Korea Department of Advanced Technology Fusion Konkuk University Seoul 143-701 South Korea Laboratory of Applied Mechanics Faculty of Applied Science Ho Chi Minh City University of Technology Ho Chi Minh 740-128 Vietnam

We investigated the effect of wing kinematics modulation, which was achieved by adjusting the location of trailing-edge constraint at the wing-root, i.e., by adjusting the wing-root offset, on the generation of aerodynamic forces in a hovering in- sect-mimicking Flapping-Wing Micro Air Vehicle （FW-MAV） by numerical and experimental studies. Three-dimensional wing kinematics measured using three synchronized high-speed cameras revealed a clear difference in the wing rotation angle of a wing section for different wing-root offsets. The extrapolated wing kinematics were in good agreement with the measured ones for various wing-root offsets. The Unsteady Blade Element Theory （UBET） was used to estimate the forces generated by the flapping wings and validated by comparison with results of measurements performed using a load cell. Although the thrust produced by a flapping wing with a wing-root offset of 0.20 c was about 4% less, its force-to-input-power ratio was about 30% and 10% higher than those with the offsets of 0.10 c and 0.15 c, respectively. This result could be explained by analyzing the effective Angle of Attack （AoA） and the force components computed by the UBET. Thus, a flapping wing with a wing-root offset of 0.20 c can be regarded as an optimal twist configuration for the development of the FW-MAV.

关键词： wing kinematics flapping-wing MAV biomimetics beetle-mimicking insect flight linear extrapolation

Effect of sintering temperature on the dielectric,ferroelectric and energy storage properties of SnO_(2)-doped Bi_(0.5)(Na_(0.8)K_(0.2))_(0.5)TiO_(3)lead-free ceramics

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Journal of Advanced Dielectrics 2020年第4期10卷 13-21页

作者： Nguyen truong-Tho Le Dai Vuong Department of Physics College of Sciences Hue UniversityHue CityVietnam Faculty of Natural Sciences Thu Dau Mot University Binh Duong Province Vietnam

Sintered lead-free Bi_(0.5)(Na_(0.8)K_(0.2)T_(0.5)(Ti0:96Sn0:04TO_(3)ceramics(BNKTS)have been fabricated via a solid-state *** effect of sintering temperature on the structural,morphological,dielectric,ferroelectric and energy storage properties of BNKTS ceramics was investigated,and it was found that the electrical properties of the synthesized ceramics increased with the increase in the sintering temperature,and the highest values were achieved at 1100℃.The ceramics sintered at the optimized temperature of 1100℃exhibited the best physical,dielectric,ferroelectric and energy storage properties,namely,high density(the relative density,ρ=5:88 ***^(-3),approximate to 96.7%of the theoretical value),high densification factor(DF=0:93),high dielectric constant(ε_(r)=1215),low dielectric loss(tanδ=0:051),highest dielectric constant(ε_(max)=4335),high remanent polarization(Pr=9:5μ***^(-2),high coercive field(E_(c)=14:3 kV/cm),high energy storage density(0.12 J/cm^(3),and high energy storage efficiency(41.7%at 46.3 kV/cm).

关键词： Lead-free ceramics BNKT sintering temperature dielectric constant

Structural Characteristics of Allomyrina Dichotoma Beetle＇s Hind Wings for Flapping Wing Micro Air Vehicle

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Journal of Bionic Engineering 2014年第2期11卷 226-235页

作者： Ngoc San Ha Quang Tri truong Hoang Vu Phan Nam Seo Goo Hoon Cheol Park Biomimetics and Intelligent Microsystem Laboratory Department of Advanced Technology Fusion Division of Interdisciplinary Studies Konkuk University Seoul 143-701 Republic of Korea

In this study, we present a complete structural analysis ofAllomyrina dichotoma beetle＇s hind wings by investigating their static and dynamic characteristics. The wing was subjected to the static loading to determine its overall flexural stiffness. Dy- namic characteristics such as natural frequency, mode shape, and damping ratio of vibration modes in the operating frequency range were determined using a Bruel ＆ Kjaer fast Fourier transform analyzer along with a laser sensor. The static and dynamic characteristics of natural Allomyrina dichotoma beetle＇s hind wings were compared to those of a fabricated artificial wing. The results indicate that natural frequencies of the natural wing were significantly correlated to the wing surface area density that was defined as the wing mass divided by the hind wing surface area. Moreover, the bending behaviors of the natural wing and artificial wing were similar to that of a cantilever beam. Furthermore, the flexural stiffness of the artificial wing was a little higher than that of the natural one whereas the natural frequency of the natural wing was close to that of the artificial wing. These results provide important information for the biomimetic design of insect-scale artificial wings, with which highly ma- neuverable and efficient micro air vehicles can be designed.

关键词： beetle hind wing flexural stiffness natural frequency mode shape Micro Air Vehicles (MAVs)

A New Species of Rhacophorus(Amphibia:Anura:Rhacophoridae)from Vietnam

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Asian Herpetological Research 2017年第4期18卷 221-234页

作者： Tao Thien NGUYEN Cuong The PHAM truong Quang NGUYEN Hoa Thi NINH Thomas ZIEGLER Vietnam National Museum of Nature Vietnam Academy of Science and Technology18 Hoang Quoc Viet RoadHanoiVietnam Institute of Ecology and Biological Resources Vietnam Academy of Science and Technology18 Hoang Quoc VietHanoiVietnam Graduate University of Science and Technology Vietnam Academy of Science and Technology18 Hoang Quoc VietCau GiayHanoiVietnam The Kyoto University Museum Kyoto UniversityYoshida HonmachiSakyokuKyoto 606-8501Japan Hanoi National University of Education 136 Xuan ThuyCau GiayHanoiVietnam AG Zoologischer Garten K6ln Riehler Strasse 173D-50735 CologneGermany Institute of Zoology University of CologneZiilpicherStrafle 47bD-50674 CologneGermany

We describe a new species of Rhacophorus based on two adult specimens collected from Hoa Binh Province, northern Vietnam. Rhacophorus hoabinhensis sp. nov. is distinguishable from its congeners on the basis of a combination of the following morphological characters： size small （SVL 31.1-32.5 mm in males）; head slightly longer than wide; vomerine teeth absent; snout short （SNL/SVL 0.16）; dorsal skin smooth; forearm and tarsus with dermal fringes; dermal appendage at vent present; webbing formula on fingers I12/3-12/3II1-2III1-1IV and on toes I3/4-1II1/2- IIII1/2-1IVI-1/2V; dorsal surface grey yellow with brown spots; lower jaw region dark grey, throat, chest and belly cream; anterior and posterior thighs, as well as ventral surface of tibia orange. The interspecific uncorrected genetic distances （16S rRNA gene） between the new species from Hoa Binh and other analyzed congeners varied from 9.8% to 17.4%. In the phylogenetic analyses, the new species revealed to be a representative of Rhacophorus and was nested within the R. hoanglienensis-orlovi species group.

关键词： Rhacophorus hoabinhensis sp.nov karst forest molecular phylogeny taxonomy Hoa Binh Province

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Historical development of karst evergreen broadleaved forests in East Asia has shaped the evolution of a hemiparasitic genus Brandisia(Orobanchaceae)

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Plant Diversity 2023年第5期45卷 501-512页

作者： Zhe Chen Zhuo Zhou Ze-Min Guo truong Van Do Hang Sun Yang Niu CAS Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of Sciences132 Lanhei RoadKunming 650201YunnanChina University of Chinese Academy of Sciences Beijing 100049China Vietnam National Museum of Nature Vietnam Academy of Science and Technology18 Hoang Quoc VietCau Giay 10000HanoiVietnam Graduate University of Science and Technology Vietnam Academy of Science and Technology18 Hoang Quoc VietCau Giay 10000HanoiVietnam

Brandisia is a shrubby genus of about eight species distributed basically in East Asian evergreen broadleaved forests(EBLFs),with distribution centers in the karst regions of Yunnan,Guizhou,and Guangxi in southwestern *** on the hemiparasitic and more or less liana habits of this genus,we hypothesized that its evolution and distribution were shaped by the development of EBLFs *** test our hypothesis,the most comprehensive phylogenies of Brandisia hitherto were constructed based on plastome and nuclear loci(nrDNA,PHYA and PHYB);then divergence time and ancestral areas were inferred using the combined nuclear loci *** analyses reconfirmed that Brandisia is a member of Orobanchaceae,with unstable placements caused by nuclear-plastid *** Brandisia,three major clades were well supported,corresponding to the three subgenera based on *** was inferred to have originated in the early Oligocene(32.69 Mya)in the Eastern Himalayas-SW China,followed by diversification in the early Miocene(19.45 Mya)in karst *** differentiation dates of Brandisia were consistent with the origin of keystone species of EBLFs in this region(e.g.,Fagaceae,Lauraceae,Theaceae,and Magnoliaceae)and the colonization of other characteristic groups(e.g.,Gesneriaceae and Mahonia).These findings indicate that the distribution and evolution of Brandisia were facilitated by the rise of the karst EBLFs in East *** addition,the woody and parasitic habits,and pollination characteristics of Brandisia may also be the important factors affecting its speciation and dispersal.

关键词： Biogeography Brandisia Evergreen broadleaved forests(EBLFs) Karst Orobanchaceae Phylogeny

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Incorporation of hydroxyapatite in crosslinked gelatin/chitosan/poly(vinyl alcohol) hybrids utilizing as reinforced composite sponges, and their water absorption ability

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Progress in Natural Science:Materials International 2021年第5期31卷 664-671页

作者： Thi Sinh Vo Tran Thi Bich Chau Vo truong Sinh Nguyen Nhan Duy Pham School of Mechanical Engineering Sungkyunkwan University Department of Chemistry Memorial University of Newfoundland Department of Industrial Management Can Tho University

The crosslinked gelatin/chitosan/poly(vinyl alcohol)/hydroxyapatite(GEL/CTS/PVA/HAp, GCPH) sponges were fabricated by a freeze-drying method to yield the reinforced composite sponges with proper features. The porosity value and pore size of the crosslinked GCPH sponges reached ～80% and 50–100 μm, respectively, which can be an appropriate range to allow cells to migrate into the reinforced composite sponges in the tissue engineering technology. Besides, the proper bonding presence between HAp particles and the crosslinked polymeric matrix or the crosslinked network formation between the polymers were also proved through fourier-transform infrared spectroscopy(FTIR), X-ray diffraction(XRD) and thermal gravimetric(TG/DTG) analysis. Owing to incorporation of HAp particles and good distribution of HAp particles inside the crosslinked polymeric matrix, their mechanical properties were improved through the determination of compression tests. Concomitantly, their water absorption ability reached effectively in both the distilled water and Na Cl solution, and their recovery also maintained well for 10 absorbing–squeezing cycles to be considered as an effective reusability for the crosslinked sponge ***, the crosslinked GCPH sponge prepared in the present study can become a potential candidate to apply especially in the biomedical/medical applications and tissue engineering technology.

关键词： Reinforced composite sponge Gelatin Chitosan Poly(vinyl alcohol) Hydroxyapatite Water absorption ability Reusability