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Semi-analytical and computational investigation of different dust loading structures affecting the performance of a fibrous air filter

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Particuology 2014年第2期12卷 60-65页

作者： Bin Xu ya wu Pengyi Cui Department of Environmental Engineering Tongji University State Key Laboratory of Pollution Control and Resource Reuse Tongji University

In this study, a semi-analytical model was developed to illustrate the relationship between filtration performance （filtration efficiency and pressure drop） and dust loading under two different particle deposit structures based on theoretical analysis and computational fluid dynamic （CFD） technology. Under the compact deposit structure, within the practical parameter ranges （fiber diameter, air velocity, dust loading mass）, a slight efficiency enhancement （∽10%） occurred at the most penetration particle size （MPPS） and pressure drop increased significantly （∽100%） in response to the solidity increase from 5% to 15%. However, under the dendritic particle deposit structure, both filtration efficiency （∽40%） and pressure drop （4600%） increased significantly with the same solidity increase due to the larger air velocity and swerve change between fibers.

关键词： Particle filtrationDeposition structureLiquid droplet filtrationFilter dust loading

Charged ultrafine particle filtration through vehicular cabin air filters

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Particuology 2016年第5期14卷 1-5页

作者： Bin Xu Yu Gong ya wu Department of Environmental Engineering Tongji University 1239 Siping Road Shanghai 200092 China Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3) Shanghai 200433 China

Understanding the effectiveness of cabin air filters is important for assessing human exposure to ultra- fine particles （UFPs） of vehicular origin. The filtration efficiency of vehicular UFPs with electric charges was investigated for different electric charge characteristics （charge state, charge polarity）. The average filtration efficiency increased ~10% as the electric charge state on the particles changed in distribution from lightly charged to highly charged. The enhancement of filtration efficiency due to electric charge was different at various filter-face air velocities. As electric charges increased, the filtration efficiency increased 12% and 9% at low air velocity （0.1 m/s） and high air velocity （0.S m/s）, respectively. The filter fiber material poses somewhat effect on the filtration efficiency change due to the electric charge. The effects of filter usage and charge polarity on filtration efficiency due to the electric charge were negligi- ble. A coefficient was empirically derived and successfully accounts for the electric charge effect on UFP filtratinn efficiency.

关键词： Particle filtration Electric charge Filtration efficiency Vehicular particle

Arsenic,Iron and Organic Matter in Quaternary Aquifer Sediments from Western Hetao Basin,Inner Mongolia

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Journal of Earth Science 2017年第3期28卷 473-483页

作者： Naijing Liu yamin Deng ya wu Geological Survey China University of GeosciencesWuhan 430074China Ningxia Institute of Geological Survey Yinchuan 750001China School of Environmental Studies China University of GeosciencesWuhan 430074China

To investigate geochemical and mineralogical features of sediments from aquifers containing high levels of dissolved arsenic（As） in western Hetao Basin, Inner Mongolia, sediment samples were collected for XRD（X-ray diffraction）, amorphous Fe/Mn oxides, and humic/fulvic acid analyses, in addition to As determination. In the study area, the total As contents in the sediments were in the range 5.3–28.8 mg/kg; while that associated with humic substances in the range 4–9 mg/kg, accounting for 26%–47% of the total As. The results of XRD analysis suggest that clay and silt contain certain small amounts of iron oxides minerals, such as ferrihydrite, hematite and goethite, whereas have higher As and Fe_2O_3 contents. Up to one third of As in the sediments could be extracted by ammonium oxalate, and high As contents were generally found in organic-rich clay or silty clay samples with high FA/HA ratio. As is strongly associated with humic substances and Fe oxyhydroxides, which may be the major sink and source of As in the aquifer sediments.

关键词： arsenic sediment organic matter Hetao Basin

Hybrid electromagnetic-triboelectric nanogenerator for harvesting vibration energy

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Nano Research 2015年第10期8卷 3272-3280页

作者： Ting Quan Yingchun wu ya yang BeijingInstituteofNanoenergyandNanosystems ChineseAcademyofSciencesBeijing100083China

We report a hybrid nanogenerator that includes a triboelectric nanogenerator （TENG） and an electromagnetic generator （EMG） for scavenging mechanical energy. This nanogenerator operates in a hybrid mode using both the triboelectric and electromagnetic induction effects. Under a vibration frequency of 14 Hz, the fabricated TENG can deliver an open-circuit voltage of about 84 V, a short-circuit current of 43 μA, and a maximum power of 1.2 mW （the corresponding power per unit mass and volume are 1.82 mW/g and 3.4 W/m^3, respectively） under a loading resistance of 2 MΩ, whereas the fabricated EMG can produce an opencircuit voltage of about 9.9 V, a short-circuit current of 7 mA, and a maximum power of 17.4 mW （the corresponding power per unit mass and volume are 0.53 mW/g and 3.7 W/m^3, respectively） under a loading resistance of 2 kΩ. Impedance matching between the TENG and EMG can be achieved using a transformer to decrease the impedance of the TENG. Moreover, the energy produced by the hybrid nanogenerator can be stored in a home-made Li-ion battery. This research represents important progress toward practical applications of vibration energy generation for realizing self-charging power cells.

关键词： hybrid nanogenerator triboelectric electromagnetic Li-ion battery vibration energy

Multi-scale analysis of void evolution in large-section plastic mold steel during multi-directional forging

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Journal of Iron and Steel Research International 2022年第12期29卷 1961-1977页

作者： Xuan Chen Bo-ya wu Bo-liang wu Xiao-chun wu Jun-wan Li School of Materials Science and Engineering Shanghai UniversityShanghai 200444China State Key Laboratory of Advanced Special Steel Shanghai UniversityShanghai 200444China

The void evolution of large-section plastic mold steel during multi-directional forging(MDF)was investigated using multiscale *** simulate the forging process of the plastic mold steel(SDP1 steel)and realize micro-void reconstruction in a representative volume element(RVE),MDF experiment and void-characteristic evaluation of the SDP1 steel were carried *** upsetting and stretching forging(TUSF)and MDF were simulated to comparatively analyze the evolution of temperature,effective stress,and effective *** embedding RVE with a micro-void and using boundary condition by point tracking into the forging process,the single-void evolution in TUSF and MDF was *** effect of void orientation on single-void evolution was also *** multi-scale analysis revealed the following results.(1)Compared with TUSF,MDF achieved a higher efficiency in void closure.(2)The closing efficiency of the void increased with the increase in angle h(the angle between the Z and long axes of the void).(3)The closing efficiency increased with the increase in the orientation angle during the forging *** the basis of the important role of the main stress in each forging step on the void closure,an integral formula of the main stress was *** main compressive-stress integration reached-0.4,the closed state of the void could be accurately determined.

关键词： Plastic mold steel Multi-directional forging Multi-scale analysis Representative volume element Void

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赫西俄德《神谱》中的提坦神族

思想战线 2009年第4期35卷 110-112页

作者：吴雅凌上海社会科学院宗教研究所

赫西俄德的《神谱》有近一半篇幅与提坦神族有关,赫西俄德在500多行神谱诗中悉心成就提坦神族形象的含糊性。重新解读长期困惑西方学者的文本疑点,能深入领会诗人隐藏于神话诗歌背后的道德教诲。

关键词：《神谱》提坦神族含糊性文本解读道德教诲

Mountain Effect and Differences in Storm Floods between Northern and Southern Sources of the Songhua River Basin

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Journal of Mountain Science 2012年第3期9卷 431-440页

作者： LI Hongyan wu ya'nan LI Xiubin Key Laboratory of Groundwater Resources and Environment Ministry of Education Jilin University Changchun 130021 China Baishan Power Plant of State Grid Xin Yuan Company Limited Huadian 132400 China

In this study, the differences in annual rainstorm changes in the Second Songhua River Basin and the Nenjiang River basin and their causes were compared from the perspective of mountain effects. The following results were drawn: (1) Altitude effect is the primary factor leading to increased rainstorms in the southern source; (2) Slope effect primarily leads to differences of the weather systems in the two sources, and thus cause the difference of the rainstorms; (3) Slope effect is responsible for the greater fluctuation in the observed floods in the southern source. These landform differences eventually lead to the differences in the characteristics of floods in the southern and northern sources. Commensurability method was used to identify the period of rainstorms in the southern and northern sources. The results showed that although rainstorms do not appear at the same time in the two sources they are characteristic of a 10 years' period in both areas. These results can serve as hydrological references for flood control and long-term flood disaster predictions.

关键词： Mountain effect Songhua River Basin Nenjiang River Basin the Second Songhua RiverBasin Storm flood

Generalization of the Hilbert-Palatini Action in Four-Dimensional Gravity

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Chinese Physics Letters 2001年第3期18卷 328-330页

作者： wu ya-Bo LI Jiu-Li Department of Physics Liaoning Normal UniversityDalian 116029

The generalized two-parametric Hilbert-Palatini action is constructed,which not only includes the well-known Hilbert-Palatini and Ashtekar gravitational theory as special cases,but also gives new *** Hamiltonian formulation,the phase space variables and the corresponding Hamiltonian constraints can be obtained,including the Ashtekar and Barbero type ***,the results of this action are the same as those given by the parametric canonical transformations,although these two methods are completely different.

关键词： Hamiltonian parametric action

Clinicopathological significance of FHIT protein expression in gastric adenocarcinoma patients

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World Journal of Gastroenterology 2005年第36期11卷 5735-5738页

作者： Po Zhao wu Liu ya-Li Lu Department of Pathology ChinesePeople's Liberation Army General Hospital Beijing 100853China

AIM： To investigate the expression of fragile histidine triad （FHIT） protein, and the possible relationship between FHIT expression and dinicopathological indices in gastric carcinoma. METHODS： FHIT protein expression was examined in 76 cases of gastric carcinoma, 58 cases of intraepithelial neoplasia, and 76 cases of corresponding normal mucosae by immunohistochemical method to analyze its relationship to histological grade, clinical stage, metastatic status and prognosis. RESULTS： The FHIT protein expression was positive in 28/76 （36.8%） cases of adenocarcinoma tissue, 22/58 （37.9%） cases of adjacent dysplastic tissue and 76/76 （100%） cases of distal normal gastric mucosa. There was a significant difference in the expression of FHIT protein between cancer or adjacent intraepithelial neoplasia and normal gastric mucosa （P = 0.000）. FHIT protein expression was found in 64.3% （18/28） of grades Ⅰ and Ⅲ cancers, and 20.8% （10/48） of grade Ⅲcancers （P = 0.000）, in 56.3% （18/32） of stages Ⅰ and Ⅱ cancers and 22.7% （10/44） of stages Ⅲ and IV cancers （P = 0.004）, and in 63.6% （14/22） of cancers without metastasis but only 25.9% （14/54） of those with metastasis （P = 0.003）. The significant difference in the expression of FHIT was found between histological grade, clinical stage and metastatic status of cancer. Follow-up data showed that there was a significant difference in median survival time between cancer patients with expression of FHIT （71 mo） and those without （33 mo, log rank = 20.78, P = 0.000）. CONCLUSION： FHIT protein is an important tumor suppressor protein. Loss of FHIT protein expression may be associated with carcinogenesis, invasion, metastasis and prognosis of gastric adenocarcinoma. 2005 The WJG Press and Elsevier Inc. All rights reserved

关键词： Gastric cancer Gene expression FHIT Prognosis