Piezo-activated guided wave propagation and interaction with damage in tubular structures

Ye Lu,Lin Ye,Dong Wang,Limin Zhou,Li Cheng 국제구조공학회 2010 Smart Structures and Systems, An International Jou Vol.6 No.7

This study investigated propagation characteristics of piezo-activated guided waves in an aluminium rectangular-section tube for the purpose of damage identification. Changes in propagating velocity and amplitude of the first wave packet in acquired signals were observed in the frequency range from 50 to 250 kHz. The difference in guided wave propagation between rectangular- and circular-section tubes was examined using finite element simulation, demonstrating a great challenge in interpretation of guided wave signals in rectangular-section tubes. An active sensor network, consisting of nine PZT elements bonded on different surfaces of the tube, was configured to collect the wave signals scattered from through-thickness holes of different diameters. It was found that guided waves were capable of propagating across the sharp tube curvatures while retaining sensitivity to damage, even that not located on the surfaces where actuators/sensors were attached. Signal correlation between the intact and damaged structures was evaluated with the assistance of a concept of digital damage fingerprints (DDFs). The probability of the presence of damage on the unfolded tube surface was thus obtained, by which means the position of damage was identified with good accuracy.

Turbine Efficiency Measurement by Thermodynamic Test Method

Zhou Ye,Pan Luoping,Cao Dengfeng 한국유체기계학회 2019 International journal of fluid machinery and syste Vol.12 No.4

According to the requirement of IEC60041, the paper introduces various turbine efficiency measurement methods, and analyzes their feature and difficulties, then gives a detailed introduction for the principle and requirement of thermodynamic test method. With an example of turbine efficiency test implemented in Costa Rica, the paper gives a complete test procedure and data calculation for thermodynamic method. Finally, a comparison and verification among thermodynamic method, ultrasonic method and Winter-Kennedy method has been made, the result shows that it has great advantage and effectivity for thermodynamic method when using in flow measurement of high water head turbine.

From 3D to 4D printing: approaches and typical applications

Ye Zhou,Wei Min Huang,Shu Feng Kang,Xue Lian Wu,Hai Bao Lu,Jun Fu,Haipo Cui 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

With the additional dimension, 4D printing is emerging as a novel technique to enable configuration switching in 3D printed items. Inthis paper, four major approaches, namely self-assembly of elements, deformation mismatch, bi-stability, and the Shape memory effect(SME), are identified as the generic approaches to achieve 4D printing. The main features of these approaches are briefly discussed. Utilizingthese approaches either individually or in a combined manner, the potential of 4D printing to reshape product design is demonstratedby a few example applications.

Molecular Cloning and Characterization of a Novel Exo-β-1,3-Galactanase from Penicillium oxalicum sp. 68

Zhou, Tong,Hu, Yanbo,Yan, Xuecui,Cui, Jing,Wang, Yibing,Luo, Feng,Yuan, Ye,Yu, Zhenxiang,Zhou, Yifa The Korean Society for Microbiology and Biotechnol 2022 Journal of microbiology and biotechnology Vol.32 No.8

Arabinogalactans have diverse biological properties and can be used as pharmaceutical agents. Most arabinogalactans are composed of β-(1→3)-galactan, so it is particularly important to identify β-1,3-galactanases that can selectively degrade them. In this study, a novel exo-β-1,3-galactanase, named PoGal3, was screened from Penicillium oxalicum sp. 68, and hetero-expressed in P. pastoris GS115 as a soluble protein. PoGal3 belongs to glycoside hydrolase family 43 (GH43) and has a 1,356-bp gene length that encodes 451 amino acids residues. To study the enzymatic properties and substrate selectivity of PoGal3, β-1,3-galactan (AG-P-I) from larch wood arabinogalactan (LWAG) was prepared and characterized by HPLC and NMR. Using AG-P-I as substrate, purified PoGal3 exhibited an optimal pH of 5.0 and temperature of 40℃. We also discovered that Zn²⁺ had the strongest promoting effect on enzyme activity, increasing it by 28.6%. Substrate specificity suggests that PoGal3 functions as an exo-β-1,3-galactanase, with its greatest catalytic activity observed on AG-P-I. Hydrolytic products of AG-P-I are mainly composed of galactose and β-1,6-galactobiose. In addition, PoGal3 can catalyze hydrolysis of LWAG to produce galacto-oligomers. PoGal3 is the first enzyme identified as an exo-β-1,3-galactanase that can be used in building glycan blocks of crucial glycoconjugates to assess their biological functions.

Probability Based Virtual Machines Placement for Green Data Center

Ye Heng-zhou,Li Tao-shen 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.12

Virtual Machine Placement (VMP) is regarded as an important criterion to improve resource utilization and reduce energy consumption for cloud data centers. The existing VMP schemes simply set the VM resource requirements fixed values and ignore their fluctuation characteristics. Assuming normal distribution resource requirements, we firstly present a model for data centers based on a more accurate energy consumption model for single machine. Then, an effective genetic algorithm is adopted to solve this model. In the algorithm, some important issues, such as the number of population, fitness function and calculating method of energy consumption are discussed. In the end, we validate our method by experiments.

Travel and Social Changes in Modern Jiangnan

Zhou, Ye East-Asian Society for Urban History 2020 Journal of east-asian urban history Vol.2 No.2

Obviously the speed of dissemination of new, modern ideas in Jiangnan was closely related to the development of transportation. Looking back at the history, the backwardness of transportation in the early modern Jiangnan restrict the dissemination of new ideas in this region and then the situation changed a lot since the 1890s, when the spatial distance between Shanghai and Jiangnan was remarkably shortened, the dissemination of new ideas was accelerated, and the new ideas in return significantly influenced the Jiangnan society. It was the constantly improved transportation that facilitated the diversification of channels disseminating information and made the dissemination itself faster. As a consequence, the new ideas, knowledge, and things were rapidly disseminated and popularized in Jiangnan, thereby giving impetus to the social changes in this region.

Numerical Research on the Unsteady Evolution Characteristics of Blade Tip Vortex for Helicopter Rotor in Forward Flight

Ye Zhou,Zhan Fengjiang,Xu Guohua 한국항공우주학회 2020 International Journal of Aeronautical and Space Sc Vol.21 No.4

A high-resolution numerical method is developed to simulate the generation and evolution progress of the blade tip vortex for helicopter rotor in forward flight. In the current method, the Navier–Stokes equation is adopted as the governing equation. Along with fifth order WENO scheme, the upwind Roe scheme is employed for the calculation of convective flux. A dual time-stepping scheme is utilized for time discretization, and the LU-SGS scheme is used for every pseudo time step. The Spalart–Allmaras model is selected as the turbulence model. To trim the rotor in forward flight, a high-efficiency trim method is introduced to the current solver. Results for cases in different forward flight conditions show that trimming process has a great influence on the evolution characteristics of the rotor tip vortex. Compared with the cases with different Mach numbers, the evolution characteristics of rotor tip vortex have larger difference for cases with different advance ratios.

Clinical Significance of BCR-ABL Fusion Gene Subtypes in Chronic Myelogenous and Acute Lymphoblastic Leukemias

Ye, Yuan-Xin,Zhou, Juan,Zhou, Yan-Hong,Zhou, Yi,Song, Xing-Bo,Wang, Jun,Lin, Li,Ying, Bin-Wu,Lu, Xiao-Jun Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

Background: Some reports have suggested that chronic myeloid leukemia (CML) patients have a higher prevalence of M-bcr than acute lymphoblastic leukemia (ALL) patients, which show a higher prevalence of m-bcr. However, the relationship between BCR-ABL subtypes and progression of CML and ALL remains unclear. Materials and Methods: 354 CML chronic phase (CML-CP) patients, 26 CML blastic phase (CML-BP) patients and 72 ALL patients before treatment with BCR-ABL positive were recruited for blood routine examination and bone marrow smear cytology. Some 80 CML-CP and 32 ALL patients after imatinib (IM) treatment were followed-up for BCR-ABL relative concentrations detected after treatment for 3, 6 and 9 months and 1 year. Results: Before treatment, CML-CP patients showed lower BCR-ABL relative concentrations with a higher proportion of M-bcr (42.7%) compared to CML-BP and ALL patients while ALL patients had a higher BCR-ABL relative concentration with high expression of m-bcr (51.4%). Patients with M-bcr demonstrated higher WBC counts than those with m-bcr and the mixed group and higher PLT counts were noted in the CML-CP and ALL groups. After imatinib (IM) treatment, patients with m-bcr showed higher BCR-ABL relative concentrations in both CML-CP and ALL groups. Conclusions: This study identified the BCR-ABL gene as an important factor in CML and ALL cases. The M-bcr subtype was associated more with CML while the m-bcr subtype was associated more with ALL. Patients with m-bcr seem to have a poorer response to IM in either CML or ALL patients compared to M-bcr patients.

A High-efficiency Trim Method for CFD Numerical Calculation of Helicopter Rotors

Zhou Ye,Guo-hua Xu,Yong-jie Shi,Run-ze Xia 한국항공우주학회 2017 International Journal of Aeronautical and Space Sc Vol.18 No.2

In order to resolve the trimming difficulty in rotor CFD calculations, a high-efficiency and improved “delta trim method” is established to compute the blade control settings that are necessary to identify the blade motion. In this method, a simplified model which combines the blade element theory and different inflow models is employed to calculate the control settings according to the target aerodynamic forces, then it is coupled into a CFD solver with unsteady Navier-Stokes equations by the delta methodology, which makes the control settings and aerodynamics calculated and updated in the meantime at every trim cycle. Different from the previous work, the current research combines the inflow model based on prescribed wake theory. Using the method established, the control settings and aerodynamic characteristics of Helishape 7A, AH-1G and Caradonna-Tung rotors are calculated. The influence of different inflow models on trimming calculations is analyzed and the computational efficiency of the current “delta trim method” is compared with that of the “CFD-based trim method”. Furthermore, for the sake of improving the calculation efficiency, a novel acceleration factor method is introduced to accelerate the trimming process. From the numerical cases, it is demonstrated that the current “delta trim method” has higher computational efficiency than “CFD-based trim method” in both hover and forward flight, and up to 70% of the amount of calculation can be saved by current “delta trim method” which turns out to be satisfactory for engineering applications. In addition, the proposed acceleration factor shows a good ability to accelerate the trim procedure, and the prescribed wake inflow model is always of better stability than other simple inflow models whether the acceleration factor is utilized in trimming calculations.

Effect of nano-carbon addition on color performance of polystyrene superstructure film

Ye-min ZHOU,Li-li Wang,Xiao-peng LI,Xiu-feng Wang,Hong-tao JIANG 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.6

Polystyrene superstructure films show faint rainbow color, and this low color saturation limits its wide application. In thispaper, polystyrene superstructure films with single bright blue color were prepared by vertical deposition self-assemblymethod using polystyrene microspheres with average diameter of 310 ± 10 nm as raw material. Polystyrene superstructurefilms were modified by adding nano-carbon powder, and effect of the amount of nano-carbon powde on color performancewas studied. The results showed that without addition of nano-carbon powder, the superstructure films showed a faint rainbowcolor, while with addition of nano-carbon power, the superstructure films exhibited a single bright blue under the same naturallight source. Changing the amount of nano-carbon powder addition could adjust color saturation of the film. With increasingthe amount of nano-carbon powder addition from 0.008 wt% to 0.01 wt%, color saturation of the superstructure filmincreased gradually. Further increasing the amount of nano-carbon powder addition to 0.011wt%, color saturation of thesuperstructure film didn’t increase anymore and tended to get dark.