Numerical investigation of the dynamic response of a simplified floating structure subjected to two underwater explosion bubbles

Xudong Jiang,Yuxiang Wang,Cheng Sun 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.11

The interaction of the two coupling bubble with a floating structure is modelled to investigate the dynamic behavior of the warship under an underwater explosion (UNDEX) by coupled Eulerian-Lagrangian (CEL) method. In this study, the CEL method is first verified by the experimental results for free field underwater explosion. Then, a series of cases for various initial distance and delay intervals between the bubble pair are implemented to analyze the deformation and damage modes of the floating structure. It is observed that for large initial distance between the bubble pair synchronously generated, the floating structure can be damaged with longitudinal bending buckling in the middle domain. When the initial distance between the bubble pair decreases to a critical value, the floating structrure is damaged with a remarkable crevasse besides the longitudinal bending buckling in the middle domain. However, under two bubbles with different phase differences, the floating structure a the deformation of the whipping motion without remarkable local structural damage. This is because there is the conspicuous despression effect between two out-of-phase bubbles, which weakens the bubble pulsation load. These phenomena present a theoretical reference for further studies on the destruction of underwater explosion on the ship structure caused by multiple bubbles generated with various phase differences.

Metastable equilibrium for the quaternary system containing with lithium+ potassium+magnesium+chloride in aqueous solution at 323K

Xudong Yu,Ying Zeng,Qinghong Yin,Dongbo Jiang 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.6

The metastable equilibrium of the system contained with lithium, potassium, magnesium, and chloridein aqueous system was investigated at 323 K using an isothermal evaporation method. The isothermal experimentaldata and physicochemical properties, such as density and refractive index of the equilibrated solution, were determined. With the experimental results, the stereo phase diagram, the projected phase diagram, the water content diagram andthe physicochemical properties versus composition diagrams were constructed. The projected phase diagram consistsof three invariant points, seven univariant curves and five crystallization fields corresponding to single salts potassiumchloride (KCl), lithium chloride monohydrate (LiCl·H2O), bischofite (MgCl2·6H2O) and two double salts lithium carnallite(LiCl·MgCl2·7H2O) and potassium carnallite (KCl·MgCl2·6H2O). Salt KCl has the largest crystallization region;it contains almost 95% of the general crystallization field.

Thermo-Mechanical Behavior of Long-Bored Energy Pile: A Full-Scale Field Investigation

Gang Jiang,Dong Shao,Chenfeng Zong,Gen Chen,Jie Huang,Cheng Lin,Xudong Wang,Yuwei Zhang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.1

A geothermal energy pile is a revolutionary piling technique that combines a pile foundation with a ground source heat pump system that not only supports the structure but also provides heating and cooling for buildings and bridges. The thermo-mechanical behavior of long energy piles in soft clay has rarely been investigated, despite their increasing utilization. A long floating energy pile with a length-to-diameter ratio of 66.7 was evaluated on its own and monitored in service of the supported structure in the city of Kunshan, China. With vertical mechanical loads, the experiment involved alternate cooling and heating cycles, allowing for careful analysis and assessment of the pile's temperature, stress, and displacement. Temperature-induced stress, axial force, and friction resistance of the pile shaft, as well as the change in displacement of the energy pile throughout building, were all studied. The field observations revealed without any surprise that a longer energy pile outperformed a shorter one in terms of heating exchange capacity with a more homogenous temperature distribution along the pile. Following a quasi-linear relationship with the temperature variation, the thermo-induced additional axial force soared with the larger length-diameter ratio of the pile and may even reach four times that of the pile under pure mechanical loads. Important additional settlements were also observed especially in cooling conditions. The shaft frictions along the long bored energy pile were found to have a complicated distribution, which requires further investigations.

An ultra-high pressure sensor based on SOI piezoresistive material

Yulong Zhao,Xudong Fang,Zhuangde Jiang,Libo Zhao 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.8

This paper describes an ultra-high pressure sensor which is in urgent need and widely used in defense industry and petroleum industry. It is designed on the combination of micro Silicon on Insulator (SOI) solid piezoresistive chip based on Micro Electro Mechanical Systems (MEMS) technique and cylindrical elastic body that could successfully convert dynamic ultra-high pressure measurement in explosion to strain measurement. Performances of the sensor including size, sensitivity, and linearity are investigated with experiment data. It’s proved that the dynamic ultra-high sensor in the range of 2GPa in this paper is successful in pressure measurement in explosion. The research of ultra-high pressure sensor in this paper could not only provide a reference for the improvement of explosive property, but also lay a foundation for research of pressure sensor in the range of 10GPa of the next step.

Simulation-Based Optical Spectra Analyses and Synthesis of Highly Monodispersed Mn-Doped ZnSe Nanocrystal

Mukerem. H Abib,Xudong Yao,Guopeng Li,Longfei Mi,Yajing Chang,Hui Wang,Dabin Yu,YANG JIANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.8

Geometrical structures of (ZnSe)n, n = 3x, (x = 1–4) and (MnxZn2xSe3x), (x = 1–4) clusters were calculated using density functional theory (DFT). Optical/absorption spectra, Raman spectra, HOMO–LUMO gap energy and binding energy of each cluster were calculated. The calculated results show the red shift of the optical/absorption spectra band caused by the manganese atoms doped in ZnSe clusters, and the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO–LUMO) gap energy value is decreased. Furthermore, we realized highly monodispersed manganese-doped zinc selenide quantum dots (Mn:ZnSe d-dots) experimentally by using a convenient route. The as-synthesized Mn:ZnSe d-dots were characterized by UV-Vis absorption, photoluminescence (PL), X-ray diffraction (XRD), TEM and HRTEM. The experimental results revealed that the as-prepared Mn:ZnSe d-dots with zincblende structure have an average size of about 3.9 nm.

Scale Synthesis of Environment Friendly CIZS/ZnS Core/Shell Quantum Dots for High Color Quality White LEDs

Mukerem Helil Abib,Yajing Chang,Xudong Yao,Guopeng Li,Dabin Yu,YANG JIANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.2

Environment-friendly CuInZnS (CIZS) core and CuInZnS/ZnS (CIZS/ZnS) core/shell quantum dots (QDs) were synthesized via a facile solution-phase method. Different methods certified that the ZnS shell was successfully coated on CIZS core. The coating of ZnS shell would lead to the quantum yield increase and optical spectra blue shifted. Furthermore, the CIZS and CIZS/ZnS had a long PL lifetime of 257.3 ns and 411.6 ns, respectively. Finally, the CIZS/ZnS QDs powder with yellow emission was used to compose white light emitting diodes (WLED) on blue LED chip. The WLED had a Ra of 80, Tc of 4793 K, and CIE coordinates of (0.346, 0.321) under 20 mA current, and had a bright warm white emission, which indicated the promising potential of the CIZS/ZnS QDs in the optoelectronics.

Partial Discharge Process and Characteristics of Oil-Paper Insulation under Pulsating DC Voltage

Bao, Lianwei,Li, Jian,Zhang, Jing,Jiang, Tianyan,Li, Xudong The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.2

Oil-paper insulation of valve-side windings in converter transformers withstand electrical stresses combining with AC, DC and strong harmonic components. This paper presents the physical mechanisms and experimental researches on partial discharge (PD) of oil-paper insulation at pulsating DC voltage. Theoretical analysis showed that the phase-resolved distributions of PDs generated from different insulated models varied as the increase of the applied voltages following a certain rule. Four artificial insulation defect models were designed to generate PD signals at pulsating DC voltages. Theoretical statements and experimental results show that the PD pulses first appear at the maximum value of the applied pulsating DC voltage, and the resolved PD phase distribution became wider as the applied voltage increased. The PD phase-resolved distributions generated from the different discharge models are also different in the phase-resolved distributions and development progress. It implies that the theoretical analysis is suitable for interpretation of PD at pulsating DC voltage.

A Fibrin Matrix Promotes the Differentiation of EMSCs Isolated from Nasal Respiratory Mucosa to Myelinating Phenotypical Schwann-Like Cells

Zhijian Zhang,Qian Chen,Jinbo Liu,Qinghua He,Yuepeng Zhou,Genbao Shao,Xianglan Sun,Xudong Cao,Aihua Gong,Ping Jiang 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.3

Because Schwann cells perform the triple tasks of myelination, axon guidance and neurotrophin synthesis, they are candidates for cell transplantation that might cure some types of nervous-system degenerative diseases or injuries. However, Schwann cells are difficult to obtain. As another option, ectomesenchymal stem cells (EMSCs) can be easily harvested from the nasal respiratory mucosa. Whether fibrin, an important transplantation vehicle, can improve the differentiation of EMSCs into Schwann-like cells (SLCs) deserves further research. EMSCs were isolated from rat nasal respiratory mucosa and were purified using anti-CD133 magnetic cell sorting. The purified cells strongly expressed HNK-1, nestin, p75NTR, S-100, and vimentin. Using nuclear staining, the MTT assay and Western blotting analysis of the expression of cell-cycle markers, the proliferation rate of EMSCs on a fibrin matrix was found to be significantly higher than that of cells grown on a plastic surface but insignificantly lower than that of cells grown on fibronectin. Additionally, the EMSCs grown on the fibrin matrix expressed myelination-related molecules, including myelin basic protein (MBP), 2’,3’-cyclic nucleotide 3’-phosphodiesterase (CNPase) and galactocerebrosides (GalCer), more strongly than did those grown on fibronectin or a plastic surface. Furthermore, the EMSCs grown on the fibrin matrix synthesized more neurotrophins compared with those grown on fibronectin or a plastic surface. The expression level of integrin in EMSCs grown on fibrin was similar to that of cells grown on fibronectin but was higher than that of cells grown on a plastic surface. These results demonstrated that fibrin notonly promoted EMSC proliferation but also the differentiation of EMSCs into the SLCs. Our findings suggested that fibrin has great promise as a cell transplantation vehicle for the treatment of some types of nervous system diseases or injuries.

A Fibrin Matrix Promotes the Differentiation of EMSCs Isolated from Nasal Respiratory Mucosa to Myelinating Phenotypical Schwann-Like Cells

Chen, Qian,Zhang, Zhijian,Liu, Jinbo,He, Qinghua,Zhou, Yuepeng,Shao, Genbao,Sun, Xianglan,Cao, Xudong,Gong, Aihua,Jiang, Ping Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.3

Because Schwann cells perform the triple tasks of myelination, axon guidance and neurotrophin synthesis, they are candidates for cell transplantation that might cure some types of nervous-system degenerative diseases or injuries. However, Schwann cells are difficult to obtain. As another option, ectomesenchymal stem cells (EMSCs) can be easily harvested from the nasal respiratory mucosa. Whether fibrin, an important transplantation vehicle, can improve the differentiation of EMSCs into Schwann-like cells (SLCs) deserves further research. EMSCs were isolated from rat nasal respiratory mucosa and were purified using anti-CD133 magnetic cell sorting. The purified cells strongly expressed HNK-1, nestin, $p75^{NTR}$, S-100, and vimentin. Using nuclear staining, the MTT assay and Western blotting analysis of the expression of cell-cycle markers, the proliferation rate of EMSCs on a fibrin matrix was found to be significantly higher than that of cells grown on a plastic surface but insignificantly lower than that of cells grown on fibronectin. Additionally, the EMSCs grown on the fibrin matrix expressed myelination-related molecules, including myelin basic protein (MBP), 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and galactocerebrosides (GalCer), more strongly than did those grown on fibronectin or a plastic surface. Furthermore, the EMSCs grown on the fibrin matrix synthesized more neurotrophins compared with those grown on fibronectin or a plastic surface. The expression level of integrin in EMSCs grown on fibrin was similar to that of cells grown on fibronectin but was higher than that of cells grown on a plastic surface. These results demonstrated that fibrin not only promoted EMSC proliferation but also the differentiation of EMSCs into the SLCs. Our findings suggested that fibrin has great promise as a cell transplantation vehicle for the treatment of some types of nervous system diseases or injuries.

Alkyl-substituted carbazole/pyridine hybrid host materials for efficient solution-processable blue- and green-emitting phosphorescent OLEDs

Chao Tang,Jianmei Chen,Yuxin Li,Xinchao Liu,Lili Zhang,Fangfang Wang,Jia Hu,Xudong Cao,Tao Jiang 대한금속·재료학회 2021 ELECTRONIC MATERIALS LETTERS Vol.17 No.2

Three new pyridine-cored alkyl-substituted carbazole derivatives of 2,6-bis(2,7-dimethyl-9H-carbazol-9-yl)pyridine(2,7-MeCzPy), 2,6-bis(3,6-dimethyl-9H-carbazol-9-yl) pyridine (3,6-MeCzPy) and 2,6-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)pyridine (3,6-tBuCzPy) were synthesized by means of connecting methyl or tert-butyl substituents on the3,6 or 2,7 positions of carbazole with pyridine ring as the core. The influence of different alkyl and linkages modeon the thermal, photophysical, electrochemical properties and devices electrolumiescent (EL) performances of thecompounds were comprehensively studied. In solution-processed blue or green phosphorescent organic light-emittingdiodes (PHOLEDs) with bis[2-(4,6-difluorophenyl)-pyridinato-N,C2] picolinate iridium(III) (FIrpic) or fac-tris(2-phenylpyridine)iridium (Ir(ppy)3) as phosphorescent dopants, EL performances follow the same sequence of 2,7-MeCzPy> 3,6-tBuCzPy > 3,6-MeCzPy, the trend is consistent with the value of triplet energies (ET). Devices hosted by2,7-MeCzPy achieving the best EL performance, exhibited maxima 13.6 cd A−1 and 7.0 lm W−1 for current efficiency(CE) and power efficiency (PE) in blue PHOLEDs, maxima 26.2 cd A−1 and 16.2 lm W−1 for CE and PE in greenPHOLEDs.