| 1. |
- Xiao, Sen, et al.
(författare)
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Analysis of chest injury in frontal impact via finite element modelling based on biomechanical experiment
- 2017
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Ingår i: Lixue Xuebao/Chinese Journal of Theoretical and Applied Mechanics. - 0459-1879. ; 49:1, s. 191-201
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Tidskriftsartikel (refereegranskat)abstract
- The usage of the seatbelt as a part of the vehicle protection system has immensely promoted occupant safety. However, recent accident investigation shows that it is necessary to increase the chest injury protective e_ciency in frontal impact condition. This study aims to investigate the influence of seatbelt system design variables on occupant chest injury related physical parameters at varying impact conditions, especially concerning with the chest deflection and distribution of rib stress/strain. The study is conducted by using human body FE model in combination with post mortem human subjects tests. An FE model of the belted occupant is therefore established by using a baseline human body FE model (GHBMC), which is validated according to detailed experimental data regarding kinematics, seatbelt force and chest deflection. A parameter study is implemented in terms of seatbelt position, seatbelt angle and impact speed to determine the influence of seatbelt utilization on occupant thoracic injury in frontal impact. The results show that the influence of seatbelt position on chest deflection and distribution of rib stress/strain is greater than that of the seatbelt angle. Meanwhile, the trends of chest deflections are the same with the trends of the rib stress/strain responses while the changes of seatbelt design variables. This study provides a virtual test method on investigation of the chest injury biomechanics related to the seatbelt design variables. Furthermore, the results from this study of chest injury mechanism will also provide a reference for optimizing of the occupant restraint system. © 2017, Editorial Office of Chinese Journal of Theoretical and Applied Mechanics. All right reserved.
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| 2. |
- Xin, Yan-Bo, et al.
(författare)
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Research progress of hydrogen tunneling in two-dimensional materials
- 2017
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Ingår i: Wuli xuebao. - : CHINESE PHYSICAL SOC. - 1000-3290. ; 66:5
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Forskningsöversikt (refereegranskat)abstract
- One-atom-thick material such as graphene, graphene derivatives and graphene-like materials, usually has a dense network lattice structure and therefore dense distribution of electronic clouds in the atomic plane. This unique structure makes it have great significance in both basic research and practical applications. Studies have shown that molecules, atoms and ions are very difficult to permeate through these above-mentioned two-dimensional materials. Theoretical investigations demonstrate that even hydrogen, the smallest in atoms, is expected to take billions of years to penetrate through the dense electronic cloud of graphene. Therefore, it is generally considered that one-atom-thin materialis impermeable for hydrogen. However, recent experimental results have shown that the hydrogen atoms can tunnel through graphene and monolayer hexagonal boron nitride at room temperature. The existence of defects in one-atomthin material can also effectively reduce the barrier height of the hydrogen tunneling through graphene. Controversy exists about whether hydrogen particles such as atoms, ions or hydrogen molecules can tunnel through two-dimensional materials, and it has been one of the popular topics in the fields of two-dimensional materials. In this paper, the recent research progressof hydrogen tunneling through two-dimensional materials is reviewed. The characteristics of hydrogen isotopes tunneling through different two-dimensional materials are introduced. Barrier heights of hydrogen tunneling through different graphene and graphene-like materials are discussed and the difficulties in its transition are compared. Hydrogen cannot tunnel through the monolayer molybdenum disulfide, only a little small number of hydrogen atoms can tunnel hrough graphene and hexagonal boron nitride, while hydrogen is relatively easy to tunnel through silicene and phosphorene. The introduction of atomic defects or some oxygen-containing functional groups into the two-dimensional material is discussed, which can effectively reduce the barrier height of the hydrogen tunneling barrier. By adding the catalyst and adjusting the temperature and humidity of the tunneling environment, the hydrogen tunneling ability can be enhanced and the hydrogen particles tunneling through the two-dimensional material can be realized. Finally, the applications of hydrogen tunneling through two-dimensional materials in ion-separation membranes, fuel cells and hydrogen storage materials are summarized. The potential applications of hydrogen permeable functional thin film materials, lithium ion battery electrode materials and nano-channel ions in low energy transmission are prospected. The exact mechanism of hydrogen tunneling through two-dimensional material is yet to be unravelled. In order to promote these applications and to realize large-scale production and precision machining of these two-dimensional materials, an in-depth understanding of the fundamental questions of the hydrogen tunneling mechanism is needed. Further studies are needed to predict the tunneling process quantitatively and to understand the effects of catalyst and the influences of chemical environments.
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| 3. |
- Cai, Xiao, et al.
(författare)
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高Ka 数下分子扩散效应对氨气/氢气/空气预混火焰结构的影响
- 2022
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Ingår i: Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics. - 0253-231X. ; 43:8, s. 2025-2032
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Tidskriftsartikel (refereegranskat)abstract
- Simultaneous planar laser induced fluorescence (PLIF) and Rayleigh scattering thermometry (RST) were applied to measure the key species and temperature fields of premixed ammonia/ hydrogen/air jet flames to investigate the effects of differential diffusion on flame structure. NH-PLIF technique was developed to properly characterize the reaction zone of ammonia flames. Three flames with similar laminar combustion characteristics but different Lewis numbers (Le) were investigated. Results show that the reaction zone are locally thickened for all flames at high Karlovitz number (Ka). Furthermore, the reaction layer thickness increases with the Le, indicating that the differential diffusion still plays a role in the turbulent combustion even in the distributed reaction zone regime.
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| 4. |
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| 5. |
- Huang, X, et al.
(författare)
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[Auto CPAP Set system for diagnosis and therapy of sleep breathing disorders].
- 1998
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Ingår i: Zhonghua jie he he hu xi za zhi = Zhonghua jiehe he huxi zazhi = Chinese journal of tuberculosis and respiratory diseases. - 1001-0939. ; 21:8, s. 468-70
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To compare the Auto CPAP Set system with standard polysomnography (PSG) in diagnosis and therapy of sleep breathing disorders. METHOD: Two studies were completed. The Auto CPAP Set system was compared with a simultaneously obtained PSG in eleven patients with sleep breathing disorders. Twenty-three additional patients with obstructive sleep apnea syndrome (OSAS) were treated by Auto CPAP Set. Student's t test was employed to evaluate statistical significance. RESULT: No differences were found between these two systems in AHI, SaO2 and the longest apnea duration (P > 0.05), and the Auto CPAP Set system had a sensitivity of 70% and a specificity 100% for diagnosis of OSAS. AHI decreased and SaO2 increased significantly in OSAS patients after treatment. CONCLUSION: The Auto CPAP Set system provides an accurate and simple method for diagnosis and therapy of sleep breathing disorders, and the time required for analysis of test results was shorter as compared with PSG.
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| 6. |
- Li, Xiao Juan, et al.
(författare)
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Research progress of frost formation on microchannel heat exchangers
- 2017
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Ingår i: Xiandai Huagong/Modern Chemical Industry. - 0253-4320. ; 37:11, s. 47-52
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Forskningsöversikt (refereegranskat)abstract
- Focusing on the frost formation in microchannel heat exchangers, this paper analyzes the effects of frost formation on the thermal performance of microchannel heat exchangers, and summarizes the influence factors that cause the microchannel heat exchangers to form frost, including environmental factors and structure factors. The latest research progress in this issue at home and abroad is reviewed.
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| 7. |
- Liu, Xiao, et al.
(författare)
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Comparison study on LES combustion models in diffusion flame
- 2018
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Ingår i: Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University. - 1006-7043. ; 39:3, s. 496-502
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Tidskriftsartikel (refereegranskat)abstract
- This study comparatively analyzes the calculation performances of different large-eddy simulation (LES) combustion models in a diffused flame simulation to investigate the performances of different LES-turbulent combustion models. The flamelet/progress variable (FPV), partially stirred reactor (PaSR), and transport joint possibility density function (PDF) combustion model are adopted to perform a numerical simulation analysis for Flame D in the Sandia Lab. The comparison between the calculation results and the test data shows that the three models can properly simulate the diffused flame. The transport PDF model based on the Eulerian stochastic field method can realize better results, especially the forecast for the intermediate radicals (OH) and the pollutant emissions (NO). However, the calculation volume is huge. The calculation speed and precision of PaSR are acceptable. The FPV method can save much CPU time, and has great value in engineering applications.
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| 8. |
- Wan, Cheng-Liang, et al.
(författare)
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基于玻璃毛细管的大气环境MeV质子微束的产生与测量 : [Production and measurement of MeV proton microbeams in atmospheric environment based on glass capillary]
- 2024
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Ingår i: Wuli xuebao. - 1000-3290. ; 73:10
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Tidskriftsartikel (refereegranskat)abstract
- 本文采用玻璃毛细管产生了大气环境中工作的2.5 MeV质子外束微束, 并对束斑直径及能量分布随玻璃毛细管与束流方向之间角度(倾角)变化进行测量. 测量结果表明, 在玻璃毛细管轴向与束流方向一致时(倾角为0°), 产生的微束中存在保持初始入射能量的直接穿透部分以及散射部分, 其中直接穿透的质子占比最大, 束斑直径也最大. 随着玻璃毛细管倾角的增大, 当其大于几何张角时, 束斑直径变小, 产生的微束全部为能量减小的散射部分, 直接穿透质子消失. 我们对质子在玻璃毛细管内传输时的内壁散射过程进行了模拟计算及离子轨迹分析, 发现大角度的散射部分决定了形成的外束微束斑外围轮廓, 而束斑中心区域由不与毛细管内壁产生任何作用的直接穿透离子构成, 其大小由玻璃毛细管出口直径以及几何容许张角决定. 采用玻璃毛细管产生的外束微束具有产生简单廉价, 微束区域定位简单的特点, 有望在辐射生物学、医学、材料等领域得到广泛应用.
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| 9. |
- Wu, Hao Yu, et al.
(författare)
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Transient response analysis of tension-leg-platformfloating offshore wind turbine under tendon failure conditions
- 2020
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Ingår i: Zhejiang Daxue Xuebao (Gongxue Ban)/Journal of Zhejiang University (Engineering Science Edition. - 1008-973X. ; 54:11, s. 2196-2203
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Tidskriftsartikel (refereegranskat)abstract
- The mooring load calculation module of the fully coupled dynamic simulation software FAST was recompiled, and the transient response of a tension-leg-platform floating offshore wind turbine (FOWT) named WindStar TLP system under tendon failure was numerically simulated using a time domain method, in terms of the coupled system of wind turbine, tension-leg-type support platform and tendons. The transient response of the key parameters, i.e., platform motions, nacelle accelerations and tensions in the remaining tendons under different wave directions in 50-year extreme condition were investigated. Results show that the transient response of platform motions, nacelle accelerations and tendon tensions under tendon failure are significant. The transient response of FOWT with the broken tendon in back waves is greater than that with the broken tendon in head waves. And when the broken tendon in back waves is aligned with the wave, the transient response of FOWT is the maximum. The safety factor for tendon system under tendon failure in 50-year extreme condition meets the requirements of specification constituted by American Bureau of Shipping (ABS), which verifies the survivability of this tension-leg-type FOWT.
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| 10. |
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