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Isolation and phylogenetic analysis of heterotrophic nitrobacteria

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Journal of Harbin Institute of Technology(New Series) 2008年第6期15卷 790-793页

作者：苏俊峰马放郭静波侯宁高珊珊王弘宇 School of Municipal and Environmental engineering Harbin Institute of Technology School of Environmental and Municipal engineering Xi'an University of Architecture and Technology dept.of Municipal engineering Wuhan University

A method about the isolation of heterotrophic nitrosobactria and the characteristics of heterotrophic nitrosobactria were *** can be seen from the fluorescence in situ hybridization results of the bio-membrane sample from the bio-ceramic reactor,the spots of green nitrosobacteria are obviously more than those of orange *** heterotrophic nitrobacteria were isolated from the bio-ceramic *** sequencing 16SrDNA and establishing the phylogenic tree,they were identified physiologically and biochemically as Pseudomonas sp..After 12 d,the COD removal efficiency of wgy55 and wgy68 were 45.03% and 50.85%,the NH4-N removal efficiency of them were 80.12% and 85.93%,and the TN removal efficiency of them were 69.71% and 64.7%.The final concentration of NO2-N of wgy55 and wgy68 was 0.753 mg/L and 0.601 mg/L,and that of NO3-N was 3.21 mg/L and 3.38 mg/*** results show that wgy55 and wgy68 have the capability of nitrification and they are heterotrophic nitrobacteria.

关键词： bio-ceranfic reactor fluorescence in situ hybridization heterotrophic nitrification

Microstructure and phase formation of mullite-Pr6O11 composite prepared by spark plasma sintering

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Journal of Rare Earths 2023年第2期41卷 283-289页

作者： Ehsan Ghasali Davoud Ghahremani Yasin Orooji Aida Faeghi-nia Asghar Kazem-zadeh Touradj Ebadzadeh College of Geography and Environmental Sciences Zhejiang Normal UniversityJinhua 321004China ceramic dept. Materials and Energy Research CenterAlborzIran Department of engineering Maybod BranchIslamic Azad UniversityMaybodIran

The present work investigates the effect of high praseodymium oxide(Pr6O11)content on the microstructure and phase formation of mullite(3Al_(2)O_(3)·2SiO_(2))precursor by means of the spark plasma sintering process.30 wt%Pr6O11was added to a mullite precursor consisting of aluminum nitrate nonahydrate and tetraethyl orthosilicate through a high energy mixer mill in ethanol *** spark plasma sintering was performed at a te mperature of 1200℃under 23 Pa vacuum co nditions by applying initial and final pressure of 10 and 30 MPa,*** analysis confirms the existence of mullite,alumina,Pr6O11,Pr2O3and quartz as the only crystalline *** images reveal an interesting deposition of hexagonal-shaped Al_(2)O_(3)particles on polished surfaces and complex oxide phases of the fiber network adhering to alumina particles in the form of tails seen on the fracture ***,the bending strength of 213±21 MPa,Vickers hardness of 9.3±0.1 MPa and fracture toughness of6.21±0.12 MPa·m1/2are obtained for the prepared composite.

关键词： Mullite Pr6O11 Composite Spark plasma sintering Rare earths

Coarse WC Particles ceramic-Metal Composite Coating by Laser Cladding

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Journal of Materials Science & Technology 1992年第3期8卷 209-213页

作者：曾晓雁朱蓓蒂陶曾毅杨树国崔昆 dept.of Mechanical engineering No.2 Huazhong University of Science and TechnologyWuhan430074China To whom correspondence should be addressed dept.of Mechanical engineering No.2 Huazhong University of Science and TechnologyWuhan430074China

The coarse WC particles ceramic-metal com- posite coatings with WC density of 67 wt-% and thickness of 1.0-1.2 mm have been cladded on 20Ni4Mo steel surface by a 2 kW CO_2 *** sintered WC particles with the size of 600-1000 μm are chosen as the main strengthening phase, Ni-base self-flux alloy as the binder in the compo- site *** microstructure and microhardness of both WC particles and binder are *** rigid ball indention with acoustic emission technique is used to evaluate the brittleness of the ***,the abrasive wear resistance of the coating is ***,the coatings with the same ratio and size of WC parti- cles in low carbon steel tube rod were cladded on 20Ni4Mo steel by atomic hydrogen welding tech- nique and analysed by the same way,their results are compared.

关键词： laser cladding ceramic-metal composite coating brittleness wear resistance

Preparation and properties of nano-composite ceramic coating by thermo chemical reaction method

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Journal of Coal Science & engineering(China) 2007年第2期13卷 211-214页

作者：马壮孙方红李智超 dept.of Material Liaoning Technical UniversityFuxin 123000China

Nano-composite ceramic coating was fabricated on Q235 steel through thermo chemical reaction method. Structure of the coating was analyzed and the properties were tested. The results show that a few of new ceramic phases, such as MgAI2O4, ZnAI2O4, AI2SiO5, Ni3Fe and Fe3AI, are formed on the coating during the process of solidifying at 600 ℃. The ceramic coating is dense and the high bonding strength is obtained. The average bonding strength between the coating and matrix could be 14.22 MPa. The acid resistance of the coating increase by 8.8 times, the alkali resistance by 4.1 times, the salt resistance bv 10.3 times, and the wear resistance bv 2.39 times.

关键词： thermo chemical reaction nano-composite ceramic coating bonding strength corrosion resistance abrasion resistance

Electrostabilized homogeneous dispersion of boron nitride nanotubes in wide-range of solvents achieved by surface polarity modulation through pyridine attachment

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Nano Research 2020年第2期13卷 344-352页

作者： Mi Se Chang Min-Sun Jang Sangsun Yang Jihun Yu Taehoon Kim Sedong Kim Hyomin Jeong Chong Rae Park Jae Won Jeong Powder/ceramic Research Division Korea Institute of Materials Science797 Changwondae-roSeongsan.guChangwon 51508Republic of Korea Research Institute of Advanced Materials and Department of Materials Science and engineering Seoul National University Seoul 08826Republic of Korea Composites Research Division Korea Institute of Materials Science797 Changwondae-roSeongsan-guChangwon 51508Republic of Korea dept.of Energy and Mech.Eng Gyeongsang National UniversityCheondaegukchi-Gil 38Tongyeong 53064Republic of Korea

Boron nitride nanotubes(BNNTs)show exceptional physical properties including high mechanical strength and thermal conductivity;however,their applications have been restricted due to limited dispersibility in processing ***,a novel BNNT dispersion method with exceptional dispersibility in a wide range of solvents has been demonstrated by surtace polarity modulation through short-molecule pyridine *** atoms in pyridine are selectively bonded to electron-deficient boron atoms of the BNNT surface through Lewis acid-base reaction,which changes the surface polarity of BNNTs from neutral to ***-dispersing pyridine-attached BNNTs(Py-BNNTs)create a thick and stable electronic double layer(EDL),resulting in uniform dispersion of BNNTs in solvents with an exceptional solubility parameter range of 18.5-48 MPa^1/*** uniform dispersion of BNNTs is maintained even after the mixing with diverse ***,composites incorporating uniformly-distributed BNNTs have been realized,and extraordinary property enhancements have been *** thermal conductivity of 20 wt.%Py-BNNT/epoxy composite has been significantly improved by 69.6%and the tensile strength of 2 wt.%Py-BNNT/PVA has been dramatically improved by 75.3%.Our work demonstrates a simple and facile route to dispersing BNNTs in diverse solvents,consequently leading to selective utlization of BNNT dispersed solvents in various application fields.

关键词： boron nitride nanotube one-dimensional nanomaterials surface polarity modulation electrostabilization boron nitride nanotube composite

Theoretical model and experimental verification of anti-penetration problems of ceramic materials

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Theoretical model and experimental verification of anti-pene...

Calculation of flash temperature for hybrid ceramic ball bearing lubricated with solid

2012年海峡两岸破坏科学/材料试验学术会议

作者： Wu Lipeng Li Yongchi School of Civil engineering Shijiazhuang Tiedao University dept.of Modern Mechanics University of Science and Technology of China

Penetration is a common phenomenon both in military field and civil *** paper focuses on the penetration of long rod projectile into ceramic ***,the cavity expansion theory is employed to derive the expression of target penetration resistance,wherein the target response is divided into four regions,*** region,radially cracked region,elastic region and undisturbed *** the investigation of the factors that influence the penetration resistance,we find that the mechanical properties of the comminuted region have main influence on the anti-penetration *** the strain rate effect of the pressure-dependent sheer relation coefficient and combined with the Tate’s model,a new engineering analytical model is *** comparison between the theoretical prediction and the experimental result shows the effectiveness of the new model.

关键词： Penetration Mechanics Strain Rate Effect Theoretical Model ceramic Materials

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Journal of Harbin Institute of Technology(New Series) 2002年第4期9卷 371-375页

作者：李秀娟王黎钦古乐齐毓霖 dept. of Electromechanical engineering

The scuffing behavior of hybrid ceramic bearing lubricated with solid is greatly affected by the contact flash temperature. Formulas are dedused using Lee’s asperity flash temperature method, to calculate the flash temperature of ball bearing lubricated with solid. The maximum flash temperature is calculated for hybrid ceramic ball bearings. The results show that under given conditions, the flash temperature of inner race is higher than that of outer race, the flash temperature of the hybrid ceramic bearing is sensitive to the load, rotational speed and race curvature. The flash temperature of inner race at 20 000 r/min is 66 9% more than that that at 11 000 r/min, and with the load changing from 1.1 kN to 2 kN, the flash temperature inner race goes up to 165 7%. Very common for high speed ball bearings, when curvature coefficients of both inner and outer race change from 0 515 to 0 56, the inner race flash temperature decreases from 421 446℃ to 56 2℃.

关键词： ball bearing scuffing failure solid lubricant flash temperature

(Ba-Pb)TiO3固溶体为基的PTCR材料及其微观结构

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无机材料学报 1986年第1期 48-54页

作者：黄仲臧 Payne D.A. 中国科学院上海硅酸盐研究所 dept.of ceramic engineering Univ.of Illinois at Urbana-Champaign U.S.A

在（Ba—Pb）TiO3固溶体系统中采用混合氧化物工艺制备了铁电相变温度为300℃的 PTCR 材料,其性能为:室温电阻率104Ω·cm;电阻率在300℃附近突变103;体积密度6.45g/cm3（～94%）。通过对样品的扫描电镜观察,研究了在该系统中材料的化... 详细信息

在（Ba—Pb）TiO3固溶体系统中采用混合氧化物工艺制备了铁电相变温度为300℃的 PTCR 材料,其性能为:室温电阻率104Ω·cm;电阻率在300℃附近突变103;体积密度6.45g/cm3（～94%）。通过对样品的扫描电镜观察,研究了在该系统中材料的化学组成（添加物）、微观结构和宏观电性能之间的一些关系。过量 BaO、Al2O3和 SiO2是本系统的有用添加物,因为它们能使材料的微观结构比较精细;Mn2+起了受主杂质的作用,它能增加材料的电阻率和电阻率～温度曲线的斜率,但是有时它会促进晶粒生长;过量 TiO2在本系统中并不适宜,因为会产生粗晶的微观结构。本实验结果清楚地表明,样品的 PTCR 性能与它们的微观结构密切相关。

关键词： PTCR 材料微观结构固溶体铁电相变晶界电阻率施主杂质受主杂质

High-performance grinding of ceramic matrix composites

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NANOTECHNOLOGY AND PRECISION engineering 2024年第3期7卷 45-55页

作者： Yin, Jingfei Xu, Jiuhua Su, Honghua Nanjing Univ Aeronaut & Astronaut Coll Mech & Elect Engn Nanjing 210016 Peoples R China AECC Shenyang Liming Aeroengine Co Ltd Dept Technol Ctr Shenyang 110043 Peoples R China

ceramic matrix composites (CMCs) are highly promising materials for the next generation of aero-engines. However, machining of CMCs suffers from low efficiency and poor surface finish, which presents an obstacle to their wider application. To overcome these problems, this study investigates high-efficiency deep grinding of CMCs, focusing on the effects of grinding depth. The results show that both the surface roughness and the depth of subsurface damage (SSD) are insensitive to grinding depth. The material removal rate can be increased sixfold by increasing the grinding depth, while the surface roughness and SSD depth increase by only about 10%. Moreover, it is found that the behavior of material removal is strongly dependent on grinding depth. As the grinding depth is increased, fibers are removed in smaller sizes, with the fiber length in chips being reduced by about 34%. However, too large a grinding depth will result in blockage by chip powder, which leads to a dramatic increase in the ratio of tangential to normal grinding forces. This study demonstrates that increasing the depth of cut is an effective approach to improve the machining efficiency of CMCs, while maintaining a good surface finish. It provides the basis for the further development of high-performance grinding methods for CMCs, which should facilitate their wider application.

关键词： ceramic matrix composite Grinding Surface finish Subsurface damage Fiber breakage C/SIC COMPOSITES MECHANISM SILICON