33 results on '"Ju-Mei Zhang"'
Search Results
2. Postharvest quality maintenance of wax apple and guava fruits by use of a fermented broth of an ε-poly-l-lysine-producing Streptomyces strain
- Author
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Jian-Ling Bai, Hui-Hui Wang, Ju-Mei Zhang, Qing-Ping Wu, Shu-Ping Mo, Ying-Long He, Shao-Quan Weng, Xiao-Juan Yang, and Ci-Zhou Li
- Subjects
Medicine ,Science - Abstract
ε-Poly-l-lysine (ε-PL) is a natural antimicrobial polymer with significant inhibitory activity against a broad spectrum of microorganisms, and nowadays used widely as a preservative in the food industry. In the present study, ε-PL broth was obtained from Streptomyces ahygroscopicus GIM8 fermentation in a nutrient-limited liquid medium. The in vitro antifungal activity of the broth against fruit pathogens Penicillium expansum and Colletotrichum gloeosporioides was investigated, and its usage for postharvest storage of two highly perishable fruits wax apple and guava was evaluated. Results showed that ε-PL concentration in the broth reached 0.61 g/L, and the nutrition level of the broth was low. The antifungal activity of ε-PL broth was comparable to that of the aqueous solution of ε-PL under the same concentration. Immersion with the diluted broth (200 mg/L ε-PL) markedly delayed the decline in the quality of postharvest wax apple and guava fruits during storage, and the decay incidences were also greatly decreased as compared to their respective controls (distilled water immersion). A further investigation demonstrated that the ε-PL broth immersion induced an increase in the activity of defense-related enzymes peroxidase and polyphenol oxidase in the two fruits during storage. The present study proved that the fermentation broth of ε-PL could be used as a promising alternative to high purity ε-PL and synthetic fungicides for preserving fruits at postharvest stage.
- Published
- 2022
3. Enhanced Corrosion and Wear Resistance of LA43M Magnesium-Lithium Alloy with Magnesium-Aluminum Layered Double Hydroxide Coating
- Author
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Ju-mei Zhang, An-rong Hou, Jia-cheng Li, Duo-duo Lian, Meng-chun Zhang, and Zhi-hu Wang
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Mechanics of Materials ,Mechanical Engineering ,General Materials Science - Published
- 2022
4. Investigating the microstructures and properties of Mg‐Al LDH film‐coated Mg‐Li alloy: Effect of hydrothermal temperature
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Ju‐mei Zhang, Jia‐cheng Li, An‐rong Hou, Xin Duan, Duo‐duo Lian, Meng‐chun Zhang, and Teng Zhang
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Marketing ,Materials Chemistry ,Ceramics and Composites ,Condensed Matter Physics - Published
- 2022
5. Quantum Dots Tracking Endocytosis and Transport of Proteins Displayed by Mammalian Cells
- Author
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Meng-Qian Zhang, Zhi-Gang Wang, Dan-Dan Fu, Ju-Mei Zhang, Hao-Yang Liu, Shu-Lin Liu, and Dai-Wen Pang
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Mammals ,Actin Cytoskeleton ,Cell Membrane ,Quantum Dots ,Animals ,Endocytosis ,Analytical Chemistry - Abstract
Mammalian cell display technology uses eukaryotic protein expression system to display proteins on cell surfaces and has become an important method in biological research. Although mammalian cell display technology has many advantages and development potential, certain attributes of the displayed protein remain uncharacterized, such as whether the displayed proteins re-enter the cell and how displayed proteins move into the cell. Here, we present the endocytosis mechanism, motility behavior, and transport kinetics of displayed proteins determined using HaloTag as the displayed protein and quantum dot-based single-particle tracking. The displayed protein enters the cell through clathrin-mediated endocytosis and is transported through the cell in three stages, which is dependent on microfilaments and microtubules. The dynamic information obtained in this study provides answers to questions about endocytosis and postendocytosis transport of displayed proteins and, therefore, is expected to facilitate the development of surface display technology.
- Published
- 2022
6. Microbiologic risk factors of recurrent choledocholithiasis post-endoscopic sphincterotomy
- Author
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Ying Li, Wen-Hui Tan, Jia-Chuan Wu, Zhi-Xin Huang, Yan-Yan Shang, Biao Liang, Jian-Hui Chen, Rui Pang, Xin-Qiang Xie, Ju-Mei Zhang, Yu Ding, Liang Xue, Mou-Tong Chen, Juan Wang, and Qing-Ping Wu
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Cholangiopancreatography, Endoscopic Retrograde ,Cohort Studies ,Sphincterotomy, Endoscopic ,Choledocholithiasis ,Treatment Outcome ,Risk Factors ,Gastroenterology ,Humans ,General Medicine - Abstract
Choledocholithiasis is a severe disorder that affects a significant portion of the world's population. Treatment using endoscopic sphincterotomy (EST) has become widespread; however, recurrence post-EST is relatively common. The bile microbiome has a profound influence on the recurrence of choledocholithiasis in patients after EST; however, the key pathogens and their functions in the biliary tract remain unclear.To investigate the biliary microbial characteristics of patients with recurrent choledocholithiasis post-EST, using next-generation sequencing.This cohort study included 43 patients, who presented with choledocholithiasis at the Guangdong Second Provincial General Hospital between May and June 2020. The patients had undergone EST or endoscopic papillary balloon dilation and were followed up for over a year. They were divided into either the stable or recurrent groups. We collected bile samples and extracted microbial DNA for analysis through next-generation sequencing. Resulting sequences were analyzed for core microbiome and statistical differences between the diagnosis groups; they were examined using the Kyoto Encyclopedia of Genes and Genomes pathway hierarchy level using analysis of variance. Correlation between the key genera and metabolic pathways in bile, were analyzed using Pearson's correlation test.The results revealed distinct clustering of biliary microbiota in recurrent choledocholithiasis. Higher relative abundances (RAs) ofWe demonstrated differences in the bile microbiome of patients with recurrent choledocholithiasis compared to that in patients with stable disease, thereby adding to the current knowledge on its microbiologic etiology.
- Published
- 2022
7. In Situ Preparation of Mg-Al-Co Layered Double Hydroxides on Microarc Oxidation Ceramic Coating of LA103Z Magnesium-Lithium Alloy for Enhanced Corrosion Resistance
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An-Rong Hou, Hui Cai, Jia-Cheng Li, Ju-mei Zhang, Kai Wang, and Xin Duan
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Materials science ,Scanning electron microscope ,Mechanical Engineering ,Alloy ,Composite number ,Layered double hydroxides ,engineering.material ,Microstructure ,Corrosion ,Dielectric spectroscopy ,Coating ,Chemical engineering ,Mechanics of Materials ,engineering ,General Materials Science - Abstract
First, microarc oxidation (MAO) was performed on the surface of the LA103Z magnesium (Mg) alloy. Then, Mg-Al-Co layered double hydroxide (LDH) coatings were grown in situ on the surface of the MAO ceramic coating via hydrothermal treatment at different temperatures. Scanning electron microscopy (SEM), energy-dispersive spectrometry, and x-ray diffraction were used to characterize the microstructure, chemical composition, and phase formation of the composite coatings. The corrosion resistance of the coatings was investigated by the polarization curve and electrochemical impedance spectroscopy. The results indicated that Mg-Al-Co LDH nanosheets covered the surface of the MAO ceramic coating and tended to grow in the recessed area. As the hydrothermal treatment temperature increased, the size of the LDH sheets increased, and the distribution became denser. The electrochemical tests showed that the self-corrosion current density (8.3260 × 10−7 A·cm−2) of the composite coatings prepared at 90 °C possessed optimal corrosion resistance, which was two orders of magnitude lower than that of the MAO ceramic coating (2.3874 × 10−5 A·cm−2). The corrosion resistance of the composite coatings decreased as the preparation temperature increased (100, 110 °C). The Mg-Al-Co LDH coating significantly enhanced the corrosion resistance of the MAO ceramic-coated alloy by sealing holes and microcracks, but high temperature destroyed the internal structure of the composite coatings and reduced their corrosion resistance.
- Published
- 2021
8. Morphology and Corrosion Resistance of MAO/Mg-Al LDH Composite Film Obtained on LA103Z Mg-Li Alloy at Different Temperatures
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Zhi-hu Wang, Cai Hui, Kai Wang, Xin Duan, Ju-mei Zhang, and Yang Zhang
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010302 applied physics ,Morphology (linguistics) ,Materials science ,Alloy ,Composite film ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,01 natural sciences ,Corrosion ,visual_art ,0103 physical sciences ,Micro arc oxidation ,Ceramics and Composites ,engineering ,visual_art.visual_art_medium ,Ceramic ,Composite material ,0210 nano-technology ,Layer (electronics) - Abstract
A solution of Al(NO3)3.9H2O and NaOH was used to perform Mg-Al LDH plugging treatment on the LA103Z magnesium-lithium alloy micro-arc oxidation ceramic layer. The effect of treatment temperature on...
- Published
- 2021
9. Effect of Hydrothermal Treatment Time on Microstructure and Corrosion Behavior of Micro-arc Oxidation/Layered Double Hydroxide Composite Coatings on LA103Z Mg-Li Alloy in 3.5 wt.% NaCl Solution
- Author
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Xin Duan, Ju-mei Zhang, Zhi-hu Wang, Hui Cai, Yang Zhang, and Kai Wang
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010302 applied physics ,Materials science ,Mechanical Engineering ,Alloy ,Composite number ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Hydrothermal circulation ,Corrosion ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Mechanics of Materials ,visual_art ,0103 physical sciences ,engineering ,visual_art.visual_art_medium ,Hydroxide ,General Materials Science ,Ceramic ,Magnesium alloy ,0210 nano-technology - Abstract
The micro-arc oxidization (MAO) ceramic layer on an LA103Z Mg-Li alloy substrate was treated with a hydrothermal treatment at 90 °C for various times. The effect of the hydrothermal treatment time on the microstructure and corrosion behavior of MAO/LDH composite coatings in 3.5 wt.% NaCl solution was investigated, and the mechanism of hydrothermal film formation and corrosion was discussed. The results show that MgO on the surface of the MAO ceramic coating was partially dissolved during the hydrothermal treatment, and the released Mg2+ ions combined with OH− ions in the hydrothermal solution to form Mg(OH)2 nanosheets, which were deposited on the surface of the ceramic coating and its pores. The hydrogen evolution rates of the MAO/LDH composite coatings rank as MAO/LDH-24 h
- Published
- 2020
10. Corrosion Resistance Enhancement of Micro-Arc Oxidation Ceramic Layer by Mg-Al-Co Layered Double Hydroxide Coating
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Zhi Hu Wang, Li Jing Bai, Ju Mei Zhang, Yan Li, and Guo Jun Zhang
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010302 applied physics ,Materials science ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,01 natural sciences ,Corrosion ,chemistry.chemical_compound ,chemistry ,Coating ,visual_art ,0103 physical sciences ,Micro arc oxidation ,Ceramics and Composites ,visual_art.visual_art_medium ,engineering ,Hydroxide ,Ceramic ,Composite material ,Magnesium alloy ,0210 nano-technology ,Layer (electronics) - Abstract
To improve the corrosion resistance of the ceramic layer prepared by micro-arc oxidation (MAO) on magnesium alloy, a hydrophobic Mg-Al-Co layered double hydroxide (LDH) coating was fabricated on MA...
- Published
- 2020
11. [Radial growth responses of four coniferous species to climate change in the Potatso National Park, China]
- Author
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Ju-Mei, Zhang, Ze-Xin, Fan, Pei-Li, Fu, Panthi, Shankar, and Hua, Tang
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China ,Tracheophyta ,Climate Change ,Parks, Recreational ,Trees - Abstract
Using the principles and methods of dendrochronology, we measured tree-ring width of four dominant coniferous species,运用树木年代学的原理和方法,对普达措国家公园大果红杉、长苞冷杉、高山松和麦吊云杉4个优势针叶树种的年轮宽度进行测量,建立年轮宽度差值年表。分析年表与香格里拉气象站的日、月气候数据的相关性,研究4个优势针叶树种的径向生长对气候因子的响应。结果表明: 大果红杉的年生长速率最高,长苞冷杉的年生长速率最低;4种针叶树径向生长对气候因子的响应存在物种特异性,大果红杉与气候因子的相关性最强,麦吊云杉的径向生长对气候因子的响应不敏感;长苞冷杉树轮宽度年表与上年冬季(11、12月)和当年夏季(7月)的平均温度呈显著正相关;大果红杉树轮宽度年表与生长季早期(6月)温度呈显著正相关,与同期降水量和相对湿度呈显著负相关;而高山松树轮宽度年表与生长季早期(5月)的降水量和相对湿度呈显著正相关,与同期最高温度呈显著负相关,表明高山松的径向生长主要受生长季早期水分可利用性的影响。.
- Published
- 2021
12. CORRIGENDUM TO "A HARMONIC MEAN INEQUALITY FOR THE POLYGAMMA FUNCTION".
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JU-MEI ZHANG and LI YIN
- Abstract
We point out that the proof of Lemma 5 in the article "A harmonic mean inequality for the polygamma function" by S. Das and A. Swaminathan contains a small mistake. Giving a new and proper proof of Lemma 5 is the main aim of this paper. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
13. Mg(OH)2 Film on Micro-arc Oxidation Ceramic Coating of AZ31 Magnesium Alloy: Preparation and Corrosion Resistance
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Zhi-Hu, WANG, primary, Ju-Mei, ZHANG, primary, Li-Jing, BAI, primary, and Guo-Jun, ZHANG, primary
- Published
- 2019
- Full Text
- View/download PDF
14. Influence of Heat Treatment on Corrosion Resistance of High-Velocity Oxygen-Fuel Sprayed WC-17Co Coatings on 42CrMo Steel
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Ju-mei Zhang, Wan-chang Sun, Pei Zhang, Feng Zhang, Chu-xu Dong, and Hui Cai
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Materials science ,Scanning electron microscope ,Mechanical Engineering ,Metallurgy ,Oxide ,Recrystallization (metallurgy) ,Microstructure ,Amorphous solid ,Corrosion ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,General Materials Science ,Polarization (electrochemistry) ,Diffractometer - Abstract
The influence of heat treatment from 500 to 1100 °C on the 5 wt.% H2SO4 solution-induced corrosion resistance of high-velocity oxygen-fuel sprayed WC-17Co coatings on 42CrMo steel was investigated, by using x-ray diffractometer (XRD), scanning electron microscopy (SEM)-energy-dispersive spectrometer (EDS), and polarization curve methods. XRD analysis showed decrease in W2C phase intensity with recrystallization of amorphous Co and generation of new Co3W3C and Co6W6C phases with heat treatment. Porosity distribution did not follow a particular pattern; it initially increased and then decreased with increasing temperature. Corrosion resistance sequence of the as-sprayed and heat-treated coatings in 5 wt.% H2SO4 solution was C-5 > C-9 > C-A > C-7 > C-11. Furthermore, microstructure and phase structure of heat-treated coatings revealed the formation of different discontinuous plate-like oxide films on the surface of the heat-treated coatings which indicated the vital effect of binder structure on the corrosion resistance.
- Published
- 2015
15. Microstructure and High-Temperature Oxidation of Ni-Si3N4 Composite Coatings by Pulse Electrodeposition
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Kun Zhao, Chun Yu Miao, Ju Mei Zhang, Li Bin Niu, Hui Cai, and Wan Chang Sun
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Materials science ,Scanning electron microscope ,Mechanical Engineering ,Alloy ,Metallurgy ,Composite number ,Energy-dispersive X-ray spectroscopy ,chemistry.chemical_element ,Substrate (electronics) ,engineering.material ,Condensed Matter Physics ,Microstructure ,Coating ,chemistry ,Mechanics of Materials ,Aluminium ,engineering ,General Materials Science ,Composite material - Abstract
Nickel matrix and Si3N4 micron particles were co-deposited on the aluminum alloy by pulse electro-deposition for high temperature performance. Meanwhile, the oxidation resistance was evaluated through the high temperature oxidation test. The phase structure, micrographs and components of the composite coatings were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) together with energy dispersive spectroscopy (EDS) respectively. The results indicated that Si3N4 particles were uniformly distributed across the coating and there were no pores and cracks or other defects at the coating/substrate interface. Ni-Si3N4 composite coatings are characterized by pyramidal micro-crystallite structure. The thickness of Ni-Si3N4 composite coatings were up to 80 μm for 2h. The results also revealed that the Ni-Si3N4 composite coatings presented better oxidation resistance than the pure Ni coating and aluminum alloy at high temperature. After oxidation at 673 K for 8h, the oxidation resistance of Ni-Si3N4 composite coatings presented the improved oxidation resistance behavior compared to pure Ni and the aluminum alloy, respectively.
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- 2015
16. Effects of NaBH4 and Heat-Treat on Corrosion Resistance of Electroless Plating Ni-B Coating
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Li Bin Niu, Hui Cai, Wan Chang Sun, Ju Mei Zhang, and Chu Xu Dong
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Materials science ,Mechanical Engineering ,Composite number ,Metallurgy ,Substrate (printing) ,engineering.material ,Condensed Matter Physics ,Electrochemistry ,Corrosion ,Electroless plating ,Coating ,Mechanics of Materials ,Plating ,engineering ,General Materials Science ,Heat treating - Abstract
Ni-B/Ni-B-B4C composite coatings on the substrate of medium-carbon steel (45#) were successfully fabricated by electroless plating in a low temperature bath. The corrosion resistance of Ni-B coating were examined by using electrochemical workstation. The results indicated that there are no pores and cracks and other defects at the interface between the substrate and composite coating. It was found that the corrosion resistance of Ni-B coating increased and then decreased with the addition of NaBH4 increasing, and the best addition in plating bath was about 0.9 g/L. While the corrosion resistance of Ni-B coating heat-treated at 400°C with NaBH4 addition 0.9 g/L was the worst.
- Published
- 2014
17. Microstructural Control of Al/Si Composites by Area-Selectively Liquid-Phase-Sintering Method
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Hui Cai, Wan Chang Sun, Peng Hui Cai, and Ju Mei Zhang
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Morphology (linguistics) ,Materials science ,Mechanics of Materials ,Mechanical Engineering ,Liquid phase ,Sintering ,General Materials Science ,Composite material ,Condensed Matter Physics ,Microstructure ,Dissolution ,Casting ,Eutectic system - Abstract
Area-selectively liquid-phase sintering (AS-LPS) method was developed to control the coarsening of Si particles in Al/60vol.% Si composites with the help of sol-gel-derived interfacial modification, achieved by pre-coating discontinuous Al2O3 film on Si powders. The results show that due to the local presence of less than 1 μm-thick films, Si particles can approximately preserve their as-received size and morphology after being sintered at 950 °C. Whereas, for those prepared by use of the unmodified Si powders, Si phases evolve to several hundred-micron-sized flakes, being similar to the typical eutectic Si in Al-Si casting alloys. It is assumed that the Al2O3-film-coated areas at Al/Si interface control the dissolution of Si into Al liquid, while in uncoated areas Al matrix and Si particles bond together by LPS, thus realizing AS-LPS.
- Published
- 2014
18. Solution-Temperature-Controlled Growth of Microarc Oxidation Coatings on Aluminum Substrates
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Peng Hui Cai, Hui Cai, Wan Chang Sun, and Ju Mei Zhang
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Materials science ,Mechanical Engineering ,Metallurgy ,chemistry.chemical_element ,engineering.material ,Condensed Matter Physics ,Coating ,chemistry ,Chemical engineering ,Mechanics of Materials ,Aluminium ,engineering ,General Materials Science ,Dissolution - Abstract
The growth of microarc oxidation (MAO) coatings on aluminum substrates was controlled via changing solution temperature from 10 to 60 °C. The results show that an elevation of the temperature lowers the applied voltage and the coating thickness. The coating formed in low-temperature solution demonstrates large-sized pores and contains lots of elements only originating from solute such as P, W, and V. On the contrary, numerous small-sized pores disperse homogeneously on the coating synthesized in high-temperature solution. It is assumed that the variation of solution temperature affects the dissolving capacity of the alkaline solution and the adsorptive capacity of solute anions, thus dominating the growth behaviors of MAO coating.
- Published
- 2014
19. Preparation and Tribological Behavior of Ni-P-B4C Electroless Coatings
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Qing Hao Yang, Ying Wang, Hui Cai, Wan Chang Sun, and Ju Mei Zhang
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Materials science ,Carbon steel ,Mechanical Engineering ,Metallurgy ,Composite number ,Alloy ,engineering.material ,Tribology ,Condensed Matter Physics ,Microstructure ,Indentation hardness ,Composite coating ,Coating ,Mechanics of Materials ,engineering ,General Materials Science ,Composite material - Abstract
In this research, micro-hardness and wear resistance of two types of electroless coatings were investigated including Ni-P and Ni-P-B4C composite coatings. Dispersible B4C particles and electroless Ni-P alloy were codeposited on carbon steel by electroless plating and then heat treated at 200, 400 and 600 °C for 1 h, respectively. The cross-section morphology and microstructure of the composite coatings were characterized. Meanwhile, the micro-hardness and tribological behavior of composite coatings were evaluated. The results showed that the Ni-P-B4C composite coating presents better wear resistance in comparison with that of Ni-P coating. The Ni-P-B4C composite coating with heat treated at 400 °C exhibits high micro-hardness and good wear resistance, which the highest hardness is 1200 HV, the minimum wear weight loss is 0.12 mg and the lowest friction coefficient is 0.2054.
- Published
- 2014
20. [Microbial Community Structure on the Root Surface of Patients with Periodontitis.]
- Author
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Ju-Mei, Zhang, Jian-Ye, Zhou, Lei, Bo, Xiao-Pan, Hu, Kang-Li, Jiao, Zhi-Jie, Li, Yue-Hong, Li, and Zhi-Qiang, Li
- Subjects
Bacteria ,RNA, Ribosomal, 16S ,Dental Plaque ,Humans ,Tooth Root ,Periodontitis - Abstract
To study the microbial community structure on the root surface of patients with periodontitis.Bacterial plaque and tissues from the root neck (RN group),root middle (RM group) and root tine (RT group) of six teeth with mobility 3 in one patient with periodontitis were sampled.The V3V4 region of 16S rRNA was sequenced on the Illumina MiSeq platform.The microbial community structure was analyzed by Mothur,Qiime and SPSS software.The principal component analysis (PCoA) results indicated that the RM samples had a similar microbial community structure as that of the RT samples,which was significant different from that of the RN samples.Thirteen phyla were detected in the three groups of samples,which included 7 dominant phyla.29 dominant genera were detected in 184 genera.The abundance ofThere is region-specificity of microbial community structure on the root surface of patients with periodontitis.
- Published
- 2017
21. The Properties of Bilinear Derivative
- Author
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Wen Yan Cui, Hong Lun Wang, and Ju Mei Zhang
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Nonlinear system ,Nonlinear Sciences::Exactly Solvable and Integrable Systems ,Parametric derivative ,Generalizations of the derivative ,Fréchet derivative ,Calculus ,Bilinear interpolation ,Applied mathematics ,General Medicine ,Bilinear form ,System of bilinear equations ,Symmetric derivative ,Mathematics - Abstract
Bilinear derivative method is widely used in calculating multi-soliton solutions of some nonlinear evolution equation. The paper proves some frequently used properties of bilinear derivative from the perspective of the definition of bilinear derivative, hoping to be useful for learning and teaching in nonlinear science.
- Published
- 2014
22. Influence of Furnace Cooling Time on Precipitation of β-Mg17Al12 Phase of AZ91 Magnesium Alloy
- Author
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Huan Huan Li, Miao Zhang, Ju Mei Zhang, Gai Juan Nan, Wen Fen Zhao, and Zhen Cao
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Materials science ,Annealing (metallurgy) ,Magnesium ,Metallurgy ,Alloy ,General Engineering ,chemistry.chemical_element ,engineering.material ,chemistry ,engineering ,Grain boundary ,Lamellar structure ,Magnesium alloy ,Pearlite ,Eutectic system - Abstract
The annealing treatment of AZ91 cast magnesium alloy was carried out at 415°C for 24h and the alloy was then slowly cooled to room temperature in furnace. As a results, the coarse divorced eutectic phase distributed along the grain boundary dissolve into Mg matrix during the isothermal process, and the thin lamellar β-Mg17Al12 phase precipitates from the magnesium solid solution with a type of pearlite precipitation during furnace cooling. During the cooling process of annealing treatment, the number of β phases as perlite-type were increased with the furnace cooling time. In the early stage of furnace cooling, the β phase nucleated preferentially in the grain near the boundary, only a small quantity of β phase precipitates.In the subsequent cooling process, the rate of precipitate about β phase increased remarked as the time of furnace cooling prolonging, the number of β phase increases dramatically, and the lamellar β phase evenly distributes inside most of the grain.
- Published
- 2014
23. Corrosion Behavior of AZ91/AZ91-0.4%Nd Alloys in 3.5wt.% NaCl
- Author
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Ming Zhu, Zhi Hu Wang, Hui Cai, Li Bin Niu, and Ju Mei Zhang
- Subjects
Acicular ,6111 aluminium alloy ,Materials science ,Metallurgy ,Alloy ,engineering ,Grain boundary ,General Medicine ,Magnesium alloy ,engineering.material ,Corrosion behavior ,Microstructure ,Corrosion - Abstract
The microstructure and corrosion behavior of commercial AZ91/AZ91-0.4%Nd alloys were investigated by OM, immersion test and weight-loss method. It was found that the number of Nd element in the AZ91 magnesium alloy has effect on the grain refining efficiency, the coarse β-Mg17Al12phase distributed along the grain boundaries transformed into granular, and the granular or acicular Al3Nd phase precipitated in matrix. The addition of Nd element significantly reduces the corrosion rate of AZ91-0.4%Nd magnesium alloy, as a result the corrosion resistance of alloy was improved obviously.
- Published
- 2013
24. Microstructure and Corrosion Behavior of AZ91-0.4%Nd Magnesium Alloy
- Author
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Zhi Hu Wang, Ming Zhu, Ju Mei Zhang, and Wan Chang Sun
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Acicular ,6111 aluminium alloy ,Materials science ,Metallurgy ,Alloy ,5052 aluminium alloy ,engineering ,General Medicine ,Magnesium alloy ,engineering.material ,Microstructure ,Corrosion behavior ,Corrosion - Abstract
The corrosion behavior of AZ91-0.4%Nd alloys was investigated by immersion test in 3.5wt.% NaCl at 25°C. The phase compositions and microstructure of the AZ91-0.4%Nd alloy were characterized by XRD and OM, respectively. The results show that the number of Nd element in the AZ91 magnesium alloy has effect on the grain refining efficiency, and the granular or acicular Al3Nd phase precipitate in matrix.The corrosion products of the AZ91-0.4%Nd alloy mainly composed of Mg(OH)2and Al. The addition of Nd element significantly refine the microstructure and improve the compactness of corrosion products of AZ91-0.4%%Nd magnesium alloy, as a result the corrosion resistance of alloy was improved obviously.
- Published
- 2013
25. Influence of Annealing Treatment on Precipitation of β-Mg17Al12 Phase of AZ80 Magnesium Alloy
- Author
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Ju Mei Zhang, Bai Ling Jiang, Zi Shan Chen, Zhi Hu Wang, and Li Bin Niu
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Materials science ,Magnesium ,Annealing (metallurgy) ,Metallurgy ,General Engineering ,chemistry.chemical_element ,Microstructure ,chemistry ,Grain boundary ,Lamellar structure ,Composite material ,Magnesium alloy ,Eutectic system ,Solid solution - Abstract
The microstructure and element distribution of AZ80 magnesium alloy as-cast and after annealing treatment were studied by OM, SEM, XRD, EDS and TEM. The results show that the coarse divorced eutectic phase distributed along the grain boundary dissolve into Mg matrix during the isothermal process at 415°C for 24h. During the cooling process of annealing treatment, the lameller-shape β-Mg17Al12 nucleated preferentially in the grain near the boundary, then grows towards the neighbor grains with longitudinal direction, which precipitated from magnesium solid solution as perlite-type precipitation. When cooled to room temperature, the lameller-shape β-Mg17Al12 was uniformly distributed in the matrix, and the lamellar spacing inside β phase is about 1-2μm.
- Published
- 2012
26. Influence of Solution Treatment on Atomic Diffusion and Mechanical Properties of AZ80 Magnesium Alloy
- Author
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Zhi Hu Wang, Li Bin Niu, Ju Mei Zhang, and Wan Chang Sun
- Subjects
Materials science ,Alloy ,Metallurgy ,General Engineering ,engineering.material ,Microstructure ,Atomic diffusion ,Phase (matter) ,Ultimate tensile strength ,engineering ,Grain boundary ,Composite material ,Magnesium alloy ,Tensile testing - Abstract
The atomic diffusion and mechanical properties of as-cast AZ80 magnesium alloy after solution treatment at different time were studied by OM,SEM,EDS as well as tensile testing. The results show that the coarse β-Mg17Al12 phase distributed along the grain boundaries as net microstructure is almost dissolved after solution treatment, and the content of Al that in the α-Mg matrix is well distributed with the solution time prolonged. Because of the β-Mg17Al12 phase reducing and granulating, the function of precipitates phase strengthening was depressed and the hardness (HB) of alloy dropped obviously. However, the tensile strength(σb ) and elongation(δ) enhanced remarkably and the yield strength (σ0.2) decreased slightly.
- Published
- 2012
27. Effect of Solution Treatment on Microstructure and Corrosion Resistance of AZ91HP Magnesium Alloy
- Author
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Yang Zhang, Hui Cai, Lingling Guo, and Ju-mei Zhang
- Subjects
Materials science ,Metallurgy ,Solution treatment ,Magnesium alloy ,Microstructure ,Corrosion - Published
- 2018
28. [Study on Microbial Diversity of Peri-implantitis Subgingival by High-throughput Sequencing]
- Author
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Zhi-jie, Li, Shao-guo, Wang, Yue-hong, Li, Dong-xiang, Tu, Shi-yun, Liu, Hong-bing, Nie, Zhi-qiang, Li, and Ju-mei, Zhang
- Subjects
DNA, Bacterial ,Bacteria ,Dental Plaque ,High-Throughput Nucleotide Sequencing ,Streptococcus ,Sequence Analysis, DNA ,Fusobacterium ,Peri-Implantitis ,Pseudomonas ,RNA, Ribosomal, 16S ,Humans ,Treponema ,Periodontitis ,Phylogeny ,Selenomonas - Abstract
To study microbial diversity of peri-implantitis subgingival with high-throughput sequencing, and investigate microbiological etiology of peri-implantitis.Subgingival plaques were sampled from the patients with peri-implantitis (D group) and non-peri-implantitis subjects (N group). The microbiological diversity of the subgingival plaques was detected by sequencing V4 region of 16S rRNA with Illumina Miseq platform. The diversity of the community structure was analyzed using Mothur software.A total of 156 507 gene sequences were detected in nine samples and 4 402 operational taxonomic units (OTUs) were found. Selenomonas, Pseudomonas, and Fusobacterium were dominant bacteria in D group, while Fusobacterium, Veillonella and Streptococcus were dominant bacteria in N group. Differences between peri-implantitis and non-peri-implantitis bacterial communities were observed at all phylogenetic levels by LEfSe, which was also found in PcoA test.The occurrence of peri-implantitis is not only related to periodontitis pathogenic microbe, but also related with the changes of oral microbial community structure. Treponema, Herbaspirillum, Butyricimonas and Phaeobacte may be closely related to the occurrence and development of peri-implantitis.
- Published
- 2015
29. Removal of bromide and bromate from drinking water using granular activated carbon
- Author
-
Ju Mei Zhang, Xiu Hua Yang, Yong Qing Zhang, and Qing Ping Wu
- Subjects
Microbiology (medical) ,Granular activated carbon ,Bromides ,Ozone ,Contact time ,Bromates ,Drinking Water ,Public Health, Environmental and Occupational Health ,Pilot Projects ,Bromate ,Carbon ,Water Purification ,Mineral water ,chemistry.chemical_compound ,Infectious Diseases ,Adsorption ,chemistry ,Bromide ,Environmental chemistry ,Ultrapure water ,Mineral Waters ,Waste Management and Disposal ,Water Pollutants, Chemical ,Water Science and Technology - Abstract
Granular activated carbon (GAC) was used to remove bromide (Br⁻) and bromate (BrO(3)(-)) from drinking water in both bench- and pilot-scale experiments. The present study aims to minimize BrO(3)(-) formation and eliminate BrO(3)(-) generated during the ozonation of drinking water, particularly in packaged drinking water. Results show that the Br⁻ and BrO(3)(-) levels in GAC-treated water decreased in both bench- and pilot-scale experiments. In the bench-scale experiments, when the empty bed contact time (EBCT) was 5 min, the highest reduction rates of Br(-) in the mineral and ultrapure water were found to be 74.9% and 91.2%, respectively, and those of BrO(3)(-) were 94.4% and 98.8%, respectively. The GAC capacity for Br⁻ and BrO(3)(-) removal increased with the increase in EBCT. Reduction efficiency was better in ultrapure water than in mineral water. In the pilot-scale experiments, the minimum reduction rates of Br⁻ and BrO(3)(-) were 38.5% and 73.2%, respectively.
- Published
- 2015
30. Investigation on the effects of ϵ-poly-L-lysine on a producing strain Streptomyces ahygroscopicus GIM8, for better understanding its biosynthesis
- Author
-
Sheng-Rong, Liu, Qing-Ping, Wu, Ju-Mei, Zhang, Shu-Ping, Mo, Chun, Xiao, and Xiao-Juan, Yang
- Subjects
Adenosine Triphosphate ,Microscopy, Electron, Transmission ,Cell Membrane ,Polylysine ,Adsorption ,Hydrogen-Ion Concentration ,Streptomyces - Abstract
ϵ-Poly-L-lysine (ϵ-PL) is an L-lysine homopolymer with strong antimicrobial activity, which is generally produced by Streptomyces strains. ϵ-PL is only produced under acidic conditions in liquid culture, and to improve the current understanding of ϵ-PL biosynthesis, the present study was undertaken to investigate the effects of ϵ-PL on its producer Streptomyces ahygroscopicus GIM8, under acidic and neutral conditions. The results indicated that a neutral pH favored ϵ-PL adsorption onto the cells, whereas minimal adsorption occurred at pH 4.0, the maximum pH for ϵ-PL production. At pH 7.0, small amounts of ϵ-PL caused considerable ATP leakage from the cells, which showed increased membrane permeability. Conversely, ATP leakage was inhibited by ϵ-PL at pH 4.0. Transmission electron microscopy investigation indicated that the cytoplasmic membrane was the primary site of ϵ-PL activity at pH 7.0, and that cell shape was maintained. Metabolic activity profiles revealed that ϵ-PL decreased cellular metabolic activity at a relatively low rate at pH 7.0. However, the toxic effect was significantly enhanced at pH 4.0. Based on these data, a mechanism for the effect of ϵ-PL on ϵ-PL-producing cells under neutral and acidic conditions is proposed. Additionally, acidic conditions may potentially be required for ϵ-PL biosynthesis in liquid culture because low pH can increase membrane permeability and prevent binding of ϵ-PL onto cells, both of which favor the secretion of the ϵ-PL produced by the cells into the broth. This research contributes to the current understanding of ϵ-PL biosynthesis.
- Published
- 2014
31. [Studies on simultaneous detection of four foodborneviruses by multiplex reverse transcription-polymerase chain reaction]
- Author
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Xiao-Xia, Kou, Qing-Ping, Wu, Lin, Yao, and Ju-Mei, Zhang
- Subjects
Rotavirus ,Feces ,Adolescent ,Reverse Transcriptase Polymerase Chain Reaction ,Child, Preschool ,Norovirus ,Food Microbiology ,Humans ,Food Contamination ,Hepatitis A virus ,Child ,Sensitivity and Specificity ,Mamastrovirus - Abstract
To establish a method for simultaneous detection of norovirus (NV), rotavirus (RV), astrovirus (AV) and hepatitis A virus (HAV) by multiplex reverse transcription-polymerase chain reaction (RT-PCR).Specific primers of the four viruses were designed based on the high conserved sequences, the reaction system and conditions optimized and the specificity and sensitivity confirmed. The method was then applied to detect the four viruses in clinical samples.The steady detection limits were 100 pg/ml for hepatitis A virus, 50 pg/ml for rotavirus, norovirus and astrovirus respectively. When the developed method was used to detect clinical fecal samples, 62 (48.44%) were identified as rotavirus, 8 (6.25%) as norovirus, 11 (8.59%) as astrovirus and 4 (3.12%) as hepatitis A virus in a total of 128 samples.Data from our study showed that multiplex RT-PCR system could be used to simultaneously detect the four viruses in routine monitoring and risk assessment in disease outbreaks with high specificity and sensitivity.
- Published
- 2008
32. Removal of bromide and bromate from drinking water using granular activated carbon.
- Author
-
Yong-qing Zhang, Qing-ping Wu, Ju-mei Zhang, and Xiu-hua Yang
- Subjects
BROMATES ,BROMIDES ,ACTIVATED carbon ,OZONIZATION ,DRINKING water quality - Abstract
Granular activated carbon (GAC) was used to remove bromide (Br
- ) and bromate (BrO3 - ) from drinking water in both bench- and pilot-scale experiments. The present study aims to minimize BrO3 - formation and eliminate BrO3 - generated during the ozonation of drinking water, particularly in packaged drinking water. Results show that the Br- and BrO3 - levels in GAC-treated water decreased in both bench- and pilot-scale experiments. In the bench-scale experiments, when the empty bed contact time (EBCT) was 5 min, the highest reduction rates of Br- in the mineral and ultrapure water were found to be 74.9% and 91.2%, respectively, and those of BrO3 - were 94.4% and 98.8%, respectively. The GAC capacity for Br- and BrO3 - removal increased with the increase in EBCT. Reduction efficiency was better in ultrapure water than in mineral water. In the pilot-scale experiments, the minimum reduction rates of Br- and BrO3 - were 38.5% and 73.2%, respectively. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
33. Inserting control points for Bezier curve approximation.
- Author
-
Ju-Mei, Zhang and Hong-Lun, Wang
- Abstract
The master benefit of squared distance minimization is that it need not parameterize the data points of the target curve, so it converges faster than those method need points parameterization. Whereas, SDM can be very sensitive to the original curve owe to its local optimization. We propose a new approach to improve this. In this paper, we associate SDM with procedures for automatically inserting and redistributing of the control points of the active Bezier curve. The effectiveness and accuracy of our approach is illustrated in experimental example. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
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