Theoretical analysis on vibration characteristic of a flexible tube under the interaction of seismic load and hydrodynamic force

Lai, Jiang,He, Chao,Sun, Lei,Li, Pengzhou Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.3

The reliability of the spent fuel pool instrument is very important for the security of nuclear power plant, especially during the earthquake. The effect of the fluid force on the vibration characteristics of the flexible tube of the spent fuel pool instrument needs comprehensive analysis. In this paper, based on the potential flow theory, the hydrodynamic pressures acting on the flexible tube were obtained. A mathematical model of a flexible tube was constructed to obtain the dynamic response considering the effects of seismic load and fluid force, and a computer code was written. Based on the mathematical model and computer code, the maximum stresses of the flexible tube in both safe shutdown earthquake and operating basis earthquake events on the spent fuel pool with three typical water levels were calculated, respectively. The results show that the fluid force has an obvious effect on the stress and strain of the flexible tube in both safe shutdown earthquake and operating basis earthquake events.

Flow-induced instability and nonlinear dynamics of a tube array considering the effect of a clearance gap

Jiang Lai,Lei Sun,Pengzhou Li 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.6

Fluidelastic instability and nonlinear dynamics of tube bundles is a key issue in a steam generator. Especially, once the post-instability motion of the tube becomes larger than the clearance gap to othertubes, effective contact or impact between the tubes under consideration and the other tube inevitable. There is seldom theoretical analysis to the nonlinear dynamic characteristics of a tube array in two-phaseflow. In this paper, experimental and numerical studies were utilized to obtain the critical velocity of theflow-induced instability of a rotated triangular tube array. The calculation results agreed well with theexperimental data. To explore the post-instability dynamics of the tube array system, a Runge-Kuttascheme was used to solve the nonlinear governing equations of tube motion. The numerical resultsindicated that, when the flow pitch velocity is larger than the critical velocity, the tube array system isundergoing a limit cycle motion, and the dynamic characteristics of the tube array are almost similar fordifferent void fractions

Mechanism analysis on fluidelastic instability of tube bundles in considering of cross-flow effects

Jiang Lai,Lei Sun,Lixia Gao,Pengzhou Li 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.1

Fluidelastic instability is a key issue in steam generator tube bundles subjected in cross-flow. With a lowflow velocity, a large amplitude vibration of the tube observed by many researchers. However, themechanism of this vibration is seldom analyzed. In this paper, the mechanism of cross-flow effects onfluidelastic instability of tube bundles was investigated. Analysis reveals that when the system reachesthe critical state, there would be two forms, with two critical velocities, and thus two expressions for thecritical velocities were obtained. Fluidelastic instability experiment and numerical analysis were conductedto obtain the critical velocity. And, if system damping is small, with increases of the flow velocity,the stability behavior of tube array changes. At a certain flow velocity, the stability of tube array reachesthe first critical state, a dynamic bifurcation occurs. The tube array returns to a stable state with continuesto increase the flow velocity. At another certain flow velocity, the stability of tube array reachesthe second critical state, another dynamic bifurcation occurs. However, if system damping is big, there isonly one critical state with increases the flow velocity. Compared the results of experiments to numericalanalysis, it shows a good agreement.

Satellite-indicated variations in China’s forests from 2001 to 2009

Lai Jiang,Jingyun Fang,Daojing Zhou,Xia Zhao 한국산림과학회 2012 Forest Science And Technology Vol.8 No.2

Variations of forest area and vegetation activity in China from 2001 to 2009 were investigated using the IGBP landcover data and the EVI (Enhanced Vegetation Index) dataset derived from Moderate-Resolution Imaging Spectroradiometer (MODIS) products in the 3 years of 2001, 2005, and 2009. The area of forests in China had increased by about 10%, and the changes in EVI-indicated vegetation activity showed large regional differences. The EVI decreased between 2001 and 2005 while it increased between 2005 and 2009 in most areas of southern China. It also indicated seasonal differences in different periods: an increase in fall between 2001 and 2005 and in spring between 2005 and 2009.

Safety and Efficacy of Ledipasvir/Sofosbuvir in a Genotype 1 HCV Infected Chinese Population: Results from a Phase 3, Clinical Trial

( Lai Wei ),( Qing Xie ),( Jin Lin Hou ),( Hong Tang ),( Qin Ning ),( Jun Cheng ),( Yuemin Nan ),( Lunli Zhang ),( Jun Li ),( Jianning Jiang ),( Megan Kim ),( Brian Mcnabb ),( Fangqiu Zhang ),( Gregor 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: Chronic hepatitis C virus (HCV) infection remains a major health threat in China, affecting at least 10 million people, with approximately 58% having genotype (GT) 1 infection. There is a critical need for simple, all oral, direct-acting antiviral regimens to treat GT1 HCV in this region. Treatment with ledipasvir (LDV)/sofosbuvir (SOF) results in high sustained virologic response rates 12 weeks after therapy (SVR12) in GT1 HCV infected patients in clinical trials and real-world settings. This study evaluated the efficacy and safety of LDV/SOF for 12 weeks in Chinese patients with chronic GT1 HCV infection. Methods: Treatment experienced and treatment naïve patients with chronic GT1 HCV infection with no cirrhosis or with compensated cirrhosis were eligible to enroll in a single-arm, openlabel trial to receive a fixed dosed combination of LDV/SOF 90/400 mg daily for 12 weeks. The primary efficacy endpoint was SVR12 using the CAP/CTM HCV 2.0 assay (LLOQ =15 IU/mL) and the primary safety endpoint was adverse events (AEs) leading to LDV/SOF discontinuation. Results: A total of 206 Chinese patients were enrolled and treated. Of these, 50% were male, 16% had compensated cirrhosis, 49% were treatment-experienced, 76% had IL28B CC genotype, and 100% had GT1b HCV infection. The mean (range) age and body mass index of enrolled subjects were 47 (21-72) years and 23 (14-34) kg/m2, respectively. The overall SVR12 rate is 100% (206/206). All 32 patients with cirrhosis (15 of whom were treatment-experienced), achieved SVR12. There were no discontinuations due to AEs. No serious or severe AEs were assessed by the investigator as related to study drug and there were no deaths. Conclusions: Treatment with the single tablet regimen of LDV/SOF for 12 weeks resulted in 100% SVR12 and was well tolerated in treatment experienced and treatment naïve GT1 HCVinfected Chinese patients with and without cirrhosis.

Protein corona on magnetite nanoparticles and internalization of nanoparticle-protein complexes into healthy and cancer cells

Jiang, Wen,Lai, Kuilin,Wu, Yao,Gu, Zhongwei 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.1

Superparamagnetic magnetite nanoparticles (MNPs) of different surface properties are incubated in complicated living fluid, including fetal bovine serum solution, cell complete culture medium and cell culture system with/without serum, to investigate the alteration of protein corona and its impact on cell internalization. The MNPs prepared by co-precipitation method are functionalized with L-Lysine (Lys), Glucosamic acid (GA) to obtain amine, carboxyl and hydroxyl groups, separately. All the particles adsorb serum proteins to form MNPs-protein complexes with the surface charge changing into negative. 1D SDS/PAGE gel images analysis indicates that the composition and content of hard protein corona on the surface of NPs are related to their functional groups and agglomeration, and the total amount of protein in the medium. In cell culture system, particles not only adsorb serum proteins, but also associate with cytosolic proteins arising from HepG2 and L02 cells. GA modified MNPs (MNPs-GA) exhibit bovine serum albumin anti-adsorption capability because of the terminal hydroxyl and carboxyl groups. MNPs-GA also shows the highest cellular uptake and label efficiency compared with uncoated MNPs and Lys modified MNPs, due to larger aggregates formation and specific protein corona composition, rather than commonly approved electrostatic interaction between particles and cells. For the first time, our results provide visualized reports on previously neglected, but indispensable protein corona of the MNPs after interaction with both healthy and cancer cells, suggesting that cytosolic protein corona from cells and aggregation of particles are important factors needed to be account for on studying the nano-bio interface.

Analytical evaluation of the influence of vertical bridge deformation on HSR longitudinal continuous track geometry

Zhipeng Lai,Lizhong Jiang,Xiang Liu,Yuntai Zhang,Tuo Zhou 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.44 No.4

A high-speed railway (HSR) bridge may undergo long-term deformation due to the degradation of material stiffness, or foundation settlement during its service cycle. In this study, an analytical model is set up to evaluate the influence of this longterm vertical bridge deformation on the track geometry. By analyzing the structural characteristics of the HSR track-bridge system, the energy variational principle is applied to build the energy functionals for major components of the track-bridge system. By further taking into account the interlayer’s force balancing requirements, the mapping relationship between the deformation of the track and the one of the bridge is established. In order to consider the different behaviors of the interlayers in compression and tension, an iterative method is introduced to update the mapping relationship. As for the validation of the proposed mapping model, a finite element model is created to compare the numerical results with the analytical results, which show a good agreement. Thereafter, the effects of the interlayer’s different properties of tension and compression on the mapping deformations are further evaluated and discussed.

Establishment and Simulation Analysis of 18 DOF Unified Dynamics Model of Automobile Chassis

Fei Lai,Cheng-Yue Jiang 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.7

The unified dynamics modeling of automobile chassis is the foundation of the chassis integrated control. Previous researches mainly focused on one or two subsystems, which could not fully reflect the dynamics characteristics of automobile chassis. In this paper, a unified dynamics mathematical model involving 18 degrees of freedom (DOF) of a two-axle vehicle is established to evaluate the ride comfort and handling stability of the vehicle, based on the coupling relationship of vehicle longitudinal, lateral and vertical dynamics. In order to verify the correctness of the 18-DOF unified dynamics model, the following three methods are used: 1) comparison with other four submodels, 2) experimental verification and 3) co-simulation test. Both simulation and test results indicate that the unified dynamics mathematical model can be used to evaluate the comprehensive dynamics performance of automobile chassis, and it is beneficial for the subsequent research of chassis integrated control system.

Protein corona on magnetite nanoparticles and internalization of nanoparticle–protein complexes into healthy and cancer cells

Wen Jiang,Kuilin Lai,Yao Wu,Zhongwei Gu 대한약학회 2014 Archives of Pharmacal Research Vol.37 No.1

Superparamagnetic magnetite nanoparticles(MNPs) of different surface properties are incubated incomplicated living fluid, including fetal bovine serumsolution, cell complete culture medium and cell culturesystem with/without serum, to investigate the alteration ofprotein corona and its impact on cell internalization. TheMNPs prepared by co-precipitation method are functionalizedwith L-Lysine (Lys), Glucosamic acid (GA) to obtainamine, carboxyl and hydroxyl groups, separately. All theparticles adsorb serum proteins to form MNPs–proteincomplexes with the surface charge changing into negative. 1D SDS/PAGE gel images analysis indicates that thecomposition and content of hard protein corona on thesurface of NPs are related to their functional groups andagglomeration, and the total amount of protein in themedium. In cell culture system, particles not only adsorbserum proteins, but also associate with cytosolic proteinsarising from HepG2 and L02 cells. GA modified MNPs(MNPs-GA) exhibit bovine serum albumin anti-adsorptioncapability because of the terminal hydroxyl and carboxylgroups. MNPs-GA also shows the highest cellular uptakeand label efficiency compared with uncoated MNPs andLys modified MNPs, due to larger aggregates formationand specific protein corona composition, rather than commonlyapproved electrostatic interaction between particles and cells. For the first time, our results provide visualizedreports on previously neglected, but indispensable proteincorona of the MNPs after interaction with both healthy andcancer cells, suggesting that cytosolic protein corona fromcells and aggregation of particles are important factorsneeded to be account for on studying the nano–biointerface.

Analysis of DDS Sampling Method and Harmonic Composition

Zhi-lai Zhang,Shao-jun Jiang,Li-li Liang 한국정보처리학회 2023 Journal of information processing systems Vol.19 No.2

Through theoretical proof and algorithm design, this paper numerically demonstrates that the three samplingmethods of DDS are equivalent in amplitude-frequency characteristics. Depending on theoretical analysis, thearticle obtains the conclusion that 2 points are optimal when sampling at 2, 3, and 4 points. Built on the dataresults, this paper obtains the fractional form of the amplitude and phase of the DDS sampled signal; in addition,this paper also obtains the design parameters of the DDS post-stage filter. It also gives a control method for thecalculation error when addressing this issue.