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Microbiologically Influenced Corrosion Behavior of Fe_(40)(CoCrMnNi)_(60) and Fe_(60)(CoCrMnNi)_(40) Medium Entropy Alloys in the Presence of Pseudomonas Aeruginosa

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Acta Metallurgica Sinica(English Letters) 2023年第3期36卷 379-390页

作者： Weiwei Chang Yangyang Li Huaibei Zheng Hongchang Qian dawei guo Shuyuan Zhang Yuntian Lou Chi Tat Kwok Lap Mou Tam dawei Zhang National Materials Corrosion and Protection Data Center Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China BRI Southeast Asia Network for Corrosion and Protection(MOE) Shunde Graduate School of University of Science and Technology BeijingFoshan 528399China State Key Laboratory of Metal Material for Marine Equipment and Application Anshan 114002China Department of Electromechanical Engineering University of MacaoMacao 999078China Institute for the Development and Quality Macao 999078China

In this work,the microbiologically influenced corrosion(MIC)of Fe_(40)(CoCrMnNi)_(60) and Fe_(60)(CoCrMnNi)_(40) medium entropy alloys(MEAs)induced by Pseudomonas aeruginosa(***)was *** behaviors during 14 days of immersion in sterile and ***-inoculated culture media are *** sterile conditions,both MEAs exhibited good corrosion resistance against the culture medium *** the presence of ***,the pitting corrosion of MEAs was *** results of inductively coupled plasma‒mass spectrometry(ICP‒MS)and potentiodynamic polarization tests showed that the presence of *** promoted the selective dissolution of passive film and accelerated the corrosion of *** results of X-ray photoelectron spectroscopy(XPS)and Mott-Schottky measurements further demonstrated the degradation effect of *** on the passive *** with Fe_(60)(CoCrMnNi)_(40),Fe_(40)(CoCrMnNi)_(60) manifested better resistance to the MIC caused by ***,which may be attributed to more Cr oxides and fewer Fe oxides of the passive film.

关键词： Microbiologically influenced corrosion Medium entropy alloys Pseudomonas aeruginosa

Visual target tracking based on multi-view feature fusion with online multiple instance learning 36

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Visual target tracking based on multi-view feature fusion wi...

Characteristics of temporal evolution of particle density and electron temperature in helicon discharge

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作者： Weixin Hua Dejun Mu dawei guo Hang Liu School of Automation Northwestern Polytechnical University Company of Shaanxi China Mobile Limited

ISBN: (纸本)9781538629185

The tracking methods under the online multiple instance learning（MIL） framework always use single channel’s information or transform the RGB image to gray image for color video tracking,which may cause the information loss of the color *** addition,the MIL tracker only use the haar-like feature to construct the target appearance and ignore the different samples have different importance to the tracking results,which is argued to susceptible to interference with complex ***,this paper presents an online visual target tracking method based on multi-view feature fusion with joint online multiple instances learning to overcome the disadvantages of the MIL ***,we extract the color histogram feature and haar-like features to construct the two type ***,we compute the bag probability by summing the instance probability in the process of updating the classifiers and construct the strong ***,the object location is achieved by fusing the two type strong *** experimental results show that the proposed method performs better than several other tracking methods like IVT,MIL,OAB and WMIL trackers with smaller central position error on challenging color video sequences.

关键词： target tracking multi-view feature fusion multiple instance learning bag probability classifier

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Plasma Science and Technology 2017年第10期19卷 26-34页

作者： Xiong YANG Mousen CHENG dawei guo Moge WANG Xiaokang LI College of Aerospace Science and Engineering National University of Defense Technology Changsha 410073 People＇s Republic of China

On the basis of considering electrochemical reactions and collision relations in detail, a direct numerical simulation model of a helicon plasma discharge with three-dimensional two-fluid equations was employed to study the characteristics of the temporal evolution of particle density and electron temperature. With the assumption of weak ionization, the Maxwell equations coupled with the plasma parameters were directly solved in the whole computational domain. All of the partial differential equations were solved by the finite element solver in COMSOL Multiphysics^（TM） with a fully coupled method. In this work, the numerical cases were calculated with an Ar working medium and a Shoji-type antenna. The numerical results indicate that there exist two distinct modes of temporal evolution of the electron and ground atom density, which can be explained by the ion pumping effect. The evolution of the electron temperature is controlled by two schemes： electromagnetic wave heating and particle collision cooling. The high RF power results in a high peak electron temperature while the high gas pressure leads to a low steady temperature. In addition, an OES experiment using nine Ar I lines was conducted using a modified CR model to verify the validity of the results by simulation, showing that the trends of temporal evolution of electron density and temperature are well consistent with the numerically simulated ones.

关键词： helicon discharge numerical simulation temporal evolution pumping effect

Experimental Investigation of a Fixed-geometry Two-dimensional Mixed-compression Supersonic Inlet with Sweep-forward High- light and Bleed Slot in an Inverted ＂X＂-type Layout

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Chinese Journal of Aeronautics 2007年第4期20卷 304-312页

作者： Wan dawei guo Rongwei College of Energy and Power Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

A fixed-geometry two-dimensional mixed-compression supersonic inlet with sweep-forward high-light and bleed slot in an inverted ＂X＂-form layout was tested in a wind tunnel. Results indicate：（1） with increases of the free stream Mach number, the total pressure recovery decreases, while the mass flow ratio increases to the maximum at the design point and then decreases; （2） when the angle of attack, a, is less than 6°, the total pressure recovery of both side inlets tends to decrease, but, on the lee side inlet, its values are higher than those on the windward side inlet, and the mass flow ratio on lee side inlet increases first and then falls, while on the windward side it keeps declining slowly with the sum of mass flow on both sides remaining almost constant; （3） with the attack angle, a, rising from 6° to 9°, both total pressure recovery and mass flow ratio on the lee side inlet fall quickly, but on the windward side inlet can be observed decreases in the total pressure recovery and increases in the mass flow ratio; （4） by comparing the velocity and back pressure characterristics of the inlet with a bleed slot to those of the inlet without, it stands to reason that the existence of a bleed slot has not only widened the steady working range of inlet, but also made an enormous improvement in its performance at high Mach numbers. Besides, this paper also presents an example to show how this type of inlet is designed.

关键词： aerospace propulsion system supersonic inlet two-dimensional mixed-compression experimental investigation bleed slot "X"-type sweep-forward high-light

The far-field plasma characterization in a 600W Hall thruster plume by laser-induced fluorescence

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Plasma Science and Technology 2020年第5期22卷 83-94页

作者： Xingyue DUAN Xiong YANG Mousen CHENG Ning guo Xiaokang LI Moge WANG dawei guo College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410000People's Republic of China Science and Technology on Vacuum Technology and Physics Laboratory Lanzhou Institute of PhysicsLanzhou 730000People's Republic of China

Non-intrusive characterization of the singly ionized xenon velocity in Hall thruster plume using laser induced fluorescence(LIF)is critical for constructing a complete picture of plume plasma,deeply understanding the ion dynamics in the plume,and providing validation data for numerical *** work presents LIF measurements of singly ionized xenon axial velocity on a grid ranging from 100 to 300 mm in axial direction and from 0 to 50 mm in radial direction for a600 W Hall thruster operating at the nominal condition of discharge voltage 300 V and discharge current 2 A,the influence of discharge voltage is investigated as *** ion velocity distribution function(IVDF)results in the far-field plume demonstrate a profile of bimodal IVDFs,especially prominent at radial distances greater than channel inner radius of 22 mm at axial position of 100 mm,which is quite different from that of the near-field plume where bimodal IVDFs occur in the central core region for the same power Hall thruster when compared to previous LIF measurements of BHT-600 by Hargus(2010 *** Power 26135).Beyond 100 mm,only single-peak IVDFs are *** two-dimensional ion velocity vector field indicates the bimodal axial IVDF is merely a geometry effect for the annular discharge channel in the far-field *** about the IVDF,the most probable velocity and the accelerating potential profile along the centerline all indicate that ions are still accelerating at axial distances greater than 100 mm,and the maximum most probable velocity measured at300 mm downstream of the exit plane is about 19 km *** addition,the most probable velocity of ions along radial direction changes a little except the lower velocity ion populations in the bimodal IVDF *** ion temperature at axial distances of 10 and 300 mm oscillates along the radial direction,while the ion temperature first increases,and then decreases for the 200 mm ***,the axial position for the ion peak axial

关键词： laser-induced fluorescence Hall thruster ion velocity distribution function optical diagnostic

Measurement of transient neutral gas puff pressure in the NUDT＿IPPTx by a fast ionization gauge

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Plasma Science and Technology 2018年第12期20卷 117-124页

作者： dawei guo Mousen CHENG Xiaokang LI Bixuan CHE Xiong YANG Moge WANG College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073People＇s Republic of China

A gas injector was designed for the 400 J/pulse prototype of the planar inductive pulsed plasma thruster（IPPT） developed by the National University of Defense Technology（NUDT_IPPTx）.As the gas puff distribution over the coil surface is critical to the NUDT_IPPTx functioning efficiently, a fast ionization gauge was developed to investigate the neutral gas pressure profiles to seek the critical time when the thruster is ignited. The gauge was calibrated for argon by using a capacitance manometer. Time-resolved pressure profiles have been acquired in the condition of the gas puff mass matching with the discharge energy and the drive coil parameters of the NUDT_IPPTx. It is demonstrated that the gas injector can supply a gas puff with a sufficiently steep（dp/dt？≈？770 kPa s-1） leading and trailing edge, and the gas puff can be compressed against the drive coil as expected. The critical ignition moment is considered to appear at some instant between 525 μs and 650 μs after the valve trigger.

关键词： inductive pulsed plasma thruster gas injection fast ionization gauge fast pulsed valve neutral gas pressure

Comparison of cellular responses across multiple passage numbers in Ba/F3-BCR-ABL cells induced by silver nanoparticles

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Science China(Life Sciences) 2012年第10期55卷 898-905页

作者： guo dawei ZHANG XiuYan HUANG ZhiHai ZHOU XueFeng ZHU LingYing ZHAO Yun GU Ning liangsu Key Laboratory for Biomaterials and Devices State Key Laboratory of BioelectronicsSchool of Biological Science&Medical EngineeringSoutheast UniversityNanjing 210096China Suzhou Key Laboratory of Biomedical Materials and Technology Research Institute of Southeast University in SuzhouSuzhou 215123China Cyrus Tang Hematology Center Jiangsu Institute o[HematologyFirst Affiliated HospitalSooehow UniversitySuzhou 215123China

With the rapid development of nanotechnology and increasingly broad bio-application of engineered nanomaterials, their bio- hazards have become a serious public concern. It is believed that the chemical nature, particle size, morphology, and surface chemistry of nanomaterials are key parameters that influence their toxicity. Although cultured ceils have been widely used to evaluate nanomaterial toxicity, it remains unclear whether the passage of these cells affects the evaluation results. In the pre- sent study, Ba/F3 cells transfected with the BCR-ABL gene were subcultured to study the effect of passage number on cell sta- bility and their cellular responses upon exposure to nanomaterials. The results demonstrated that proliferation, cellular senes- cence, BCR-ABL gene expression, cell cycle and apoptosis were stable across multiple passages. Senescence and BCR-ABL gene expression of cells from different passage cells were unchanged when treated with silver nanoparticles （AgNPs）. In addi- tion, the cells at multiple passage numbers were all arrested in the G2/M phase and apoptosis was induced by the AgNPs. These nanoparticles could enter cells via endocytosis and localize in the cndosomes, which were also not influenced by passage number. These data suggest that short-term passage would not affect cultured cell stability and toxicity assessment using these cells would be consistent when maintained appropriately.

关键词： silver nanoparticles (AgNPs) cellular response cell passage stability uptake

Analysis of Winter Physical Training and Functional Reserve in College Physical Education Teaching

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Journal of Contemporary Educational Research 2023年第7期7卷 26-29页

作者： dawei guo Shaanxi Xueqian Normal University Xi’an 710100Shaanxi ProvinceChina

Physical training and functional reserve in winter physical education teaching can optimize the energy consumption of the body,regulate cardiopulmonary function,and stabilize *** is essential to clarify the strategies of winter physical training and functional reserve as well as the existing issues in college physical education teaching,which subsequently improves students’physical functions and achieves comprehensive development goals.

关键词： College physical education teaching Winter Physical training Functional reserve

线性模型中假设是凸锥时似然比统计量的零分布

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系统科学与数学 1999年第3期19卷 274-281页

作者：郭大伟安徽师范大学数学系芜湖241000

对于有正态误差和已知协方差阵的线性模型，讨论了参数域是凸锥的假设检验问题．在考察了似然比统计量的性质后，表明了只要似然比统计量是观察值的凸函数，则似然比统计量的零分布是Ｘ２－分布的混合，而此前的结果是仅当零假设或备择... 详细信息

对于有正态误差和已知协方差阵的线性模型，讨论了参数域是凸锥的假设检验问题．在考察了似然比统计量的性质后，表明了只要似然比统计量是观察值的凸函数，则似然比统计量的零分布是Ｘ２－分布的混合，而此前的结果是仅当零假设或备择假设形成线性空间时才可用．

关键词：线性模型似然比凸锥零分布假设检验