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CFD based simulations of flutter characteristics of ideal thin plates with and without central slot
Zhu, Zhi-Wen,Chen, Zheng-Qing,Gu, Ming Techno-Press 2009 Wind and Structures, An International Journal (WAS Vol.12 No.1
In this paper, the airflow around an ideal thin plate (hereafter referred to as ITP) with various ratios of central slot is simulated by using the finite-difference-method (FDM)-based Arbitrary-Lagrangian-Eulerian descriptions for the rigid oscillating body. The numerical procedure employs the second-order projection scheme to decouple the governing equations, and the multigrid algorithm with three levels to improve the computational efficiency in evaluating of the pressure equation. The present CFD method is validated through comparing the computed flutter derivatives of the ITP without slot to Theodorsen analytical solutions. Then, the unsteady aerodynamics of the ITP with and without central slot is investigated. It is found that even a smaller ratio of central slot of the ITP has notable effects on pressure distributions of the downstream section, and the pressure distributions on the downstream section will further be significantly affected by the slot ratio and the reduced wind speeds. Continuous increase of $A_2^*$ with the increase of central slot may be the key feature of the slotted ITP. Finally, flutter analyses based on the flutter derivatives of the slotted ITP are performed, and moreover, flutter instabilities of a scaled sectional model of a twin-deck bridge with various ratios of deck slot are investigated. The results confirm that the central slot is effective to improve bridge flutter stabilities, and that the flutter critical wind speeds increase with the increase of slot ratio.
Self‐assembly of covalent porphyrin compound and its enhanced electrochemiluminescence performance
Wen-Kai Zhu,Wen-Rong Cai,Zhen-Zhi Yin,Ming-Jie Cheng,Kong Yong 대한화학회 2022 Bulletin of the Korean Chemical Society Vol.43 No.12
A novel Zn-coordination covalent porphyrin assembly (TCPP-BZA-Zn) is designed. The assembly structure is synthesized through the amidation reac- tion between the porphyrin terminal carboxyl group and the amino group of benzylamine (BZA), and further assembled through π–π stacking. In particular, the inherently ordered structure of TCPP-BZA-Zn with Zn as the catalytic active center endows the porphyrin assembly structure with several obvious advantages, such as high ion transport properties and high electrocatalytic per- formance. In the presence of hydrogen peroxide as a co-reaction reagent, TCPP-BZA-Zn/GCE showed excellent ECL behavior. The amplification phenome- non of ECL was further studied by cyclic voltammetry and the corresponding mechanism was proposed. Based on TCPP-BZA-Zn, an electrochemilumines- cence sensor was constructed for copper ion detection. The ECL intensity of the sensor shows a good linear relationship with the concentration of copper ion in the range of 10 nM–1 mM, and the detection limit is 1.3 nM.
CFD based simulations of flutter characteristics of ideal thin plates with and without central slot
Zhi-wen Zhu,Zheng-qing Chen,Ming Gu 한국풍공학회 2009 Wind and Structures, An International Journal (WAS Vol.12 No.1
In this paper, the airflow around an ideal thin plate (hereafter referred to as ITP) with various ratios of central slot is simulated by using the finite-difference-method (FDM)-based Arbitrary-Lagrangian-Eulerian descriptions for the rigid oscillating body. The numerical procedure employs the second-order projection scheme to decouple the governing equations, and the multigrid algorithm with three levels to improve the computational efficiency in evaluating of the pressure equation. The present CFD method is validated through comparing the computed flutter derivatives of the ITP without slot to Theodorsen analytical solutions. Then, the unsteady aerodynamics of the ITP with and without central slot is investigated. It is found that even a smaller ratio of central slot of the ITP has notable effects on pressure distributions of the downstream section, and the pressure distributions on the downstream section will further be significantly affected by the slot ratio and the reduced wind speeds. Continuous increase of with the increase of central slot may be the key feature of the slotted ITP. Finally, flutter analyses based on the flutter derivatives of the slotted ITP are performed, and moreover, flutter instabilities of a scaled sectional model of a twin-deck bridge with various ratios of deck slot are investigated. The results confirm that the central slot is effective to improve bridge flutter stabilities, and that the flutter critical wind speeds increase with the increase of slot ratio.
<i>Chd7</i> Is Critical for Early T-Cell Development and Thymus Organogenesis in Zebrafish
Liu, Zhi-Zhi,Wang, Zi-Long,Choi, Tae-Ik,Huang, Wen-Ting,Wang, Han-Tsing,Han, Ying-Ying,Zhu, Lou-Yin,Kim, Hyun-Taek,Choi, Jung-Hwa,Lee, Jin-Soo,Kim, Hyung-Goo,Zhao, Jian,Chen, Yue,Lu, Zhuo,Tian, Xiao-L Elsevier 2018 The American journal of pathology Vol.188 No.4
<P>Coloboma, heart defect, atresia choanae, retarded growth and development, genital hypoplasia, ear anomalies/deafness (CHARGE) syndrome is a congenital disorder affecting multiple organs and mainly caused by mutations in CHD7, a gene encoding a chromatin-remodeling protein. Immunodeficiency and reduced T cells have been noted in CHARGE syndrome. However, the mechanisms underlying T lymphopenia are largely unexplored. Herein, we observed dramatic decrease of T cells in both chd7knockdown and knockout zebrafish embryos. Unexpectedly, hematopoietic stem and progenitor cells and, particularly, lymphoid progenitor cells were increased peripherally in nonthymic areas in chd7-deficient embryos, unlikely to contribute to the T-cell decrease. Further analysis demonstrated that both the organogenesis and homing function of the thymus were seriously impaired. Chd7 might regulate thymus organogenesis through modulating the development of both neural crest cell-derived mesenchyme and pharyngeal endoderm-derived thymic epithelial cells. The expression of faxn1, a central regulator of thymic epithelium, was remarkably down-regulated in the pharyngeal region in chd7-deficient embryos. Moreover, the T-cell reduction in chd7-deficient embryos was partially rescued by overexpressingfoxnl, suggesting that restoring thymic epithelium may be a potential therapeutic strategy for treating immunodeficiency in CHARGE syndrome. Collectively, the results indicated that chd7 was critical for thymic development and T-lymphopenia in CHARGE syndrome may be mainly attributed to the defects of thymic organogenesis. The current finding may benefit the diagnosis and therapy of T lymphopenia and immunodeficiency in CHARGE syndrome.</P>
The Phytotoxic Effects of Selenium–Mercury Interactions on Root Growth in Brassica rapa (LvLing)
Zhi-Wei Bian,Jian Chen,Hui Li,Dan-Dan Liu,Li-Fei Yang,Yue-Lin Zhu,Wen-Li Zhu,Wei Liu,Zheng-Zheng Ying 한국원예학회 2016 Horticulture, Environment, and Biotechnology Vol.57 No.3
Rapid industrial and agricultural development has dramatically increased the emission of selenium (Se) and mercury (Hg) into the environment. Combined soil pollution by Se and Hg poses a potential threat to crop production. However, no toxic effects of Hg–Se interactions on plants have been reported previously. In this study, we investigated the effects of Hg–Se interactions on biochemical and physiological indices in the roots of Brassica rapa (LvLing). Seedlings were treated hydroponically with solutions of mercury chloride (1 μM), sodium selenite (4 μM), or a combination of the two. Combined Hg+Se treatment significantly inhibited root growth, reduced root biomass, and enhanced reactive oxygen species (ROS) and malondialdehyde accumulation and led to a loss of plasma membrane integrity. The combined treatment increased glutathione peroxidase, glutathione S-transferase, and peroxidase activity, reduced superoxide dismutase activity, and had no effect on catalase activity. In addition, we detected increased glutathione concentrations in root tips and reduced ascorbic acid concentrations in the presence of Hg+Se relative to individual treatments with these elements. Thus, Hg–Se interactions enhanced oxidative injury, cell death, and phytotoxicity in B. rapa roots.
Full-scale testing and modeling of the mechanical behavior of shield TBM tunnel joints
Wen-qi Ding,Yi-cheng Peng,Zhi-guo Yan,Bi-wei Shen,He-hua Zhu,Xin-xin Wei 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.3
For shield TBM (Tunnel Boring Machine) tunnel lining, the segment joint is the most critical component for determining the mechanical response of the complete lining ring. To investigate the mechanical behavior of the segment joint in a water conveyance tunnel, which is different from the vehicle tunnel because of the external loads and the high internal water pressure during the tunnel’s service life, full-scale joint tests were conducted. The main advantage of the joint tests over previous ones was the definiteness of the loads applied to the joints using a unique testing facility and the acquisition of the mechanical behavior of actual joints. Furthermore, based on the test results and the theoretical analysis, a mechanical model of segment joints has been proposed, which consists of all important influencing factors,including the elastic-plastic behavior of concrete, the pre-tightening force of the bolts and the deformations of all joint components, i.e., concrete blocks, bolts and cast iron panels. Finally, the proposed mechanical model of segment joints has been verified by the aforementioned full-scale joint tests.
Zhi-Hong Xin,Li-Tian,Tian-jiao Zhu,Wen-Liang Wang,Lin Du,Yu-chun Fang,Qian-Qun Gu,Wei-Ming Zhu 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.7
Two isocoumarin derivatives, stoloniferol A (1) and B (2), a known 5α, 8α-epidioxy-23-methyl- (22E, 24R)-ergosta-6, 22-dien-3β-ol (3), and a known dihydrocitrinone (4) were isolated from the ethyl acetate extract of the sea squirt-derived fungus, Penicillium stoloniferum QY2-10, and a halophilic fungus, Penicillium notatum B-52, respectively. Their structures were elucidated by spectroscopic methods and optical rotation. The stereochemistry of 2 was determined on the basis of different NOE experiments and chemical transformation. Compound 3 showed cytotoxicity against P388 cells, with an IC50 value of 4.07 µM.
Abietane Diterpenoids from Perovskia atriplicifolia and Their Anti-HBV Activities
Zhi-Yong Jiang,Zhong-Qiu Li,Chao-Guan Huang,Jun Zhou,Qiu-Fen Hu,Wen-Xing Liu,Xiang-Zhong Huang,Wei Wang,Li-Zhu Zhang,Fu-Ting Xia 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.2
Bioassay-guided phytochemical investigation on the 90% EtOH extract of Perovskia atriplicifolia resulted in the isolation of eight abietane diterpenoids, including three new ones (1–3). Based on spectroscopic methods involving 1D and 2D NMR spectroscopy techniques, mass spectrometry, and optical rotation, the structures of the new compounds (1–3) were unambiguously characterized. Compounds 1–2 and 4–8 were evaluated for their anti-HBV (hepatitis B virus) activity in HepG 2.2.15 cell line. Results suggested rosmadial (8) had the most anti-HBV potency, suppressing the secretion of HBsAg and HBeAg, with IC50 values of 0.09 and 0.34 mM, respectively.