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1.
YanXin Dan Takashi Costa Atsushi Nakamura Keiji Komatsu Hidetoshi Saitoh 《Ceramics International》2021,47(9):11862-11869
The morphology and microstructure of splats impact the comprehensive capability of a new coating methodology called chelate flame spraying (CFS). This study addresses the quantitative characterization of the spread morphologies of flame sprayed Er2O3 splats directly deposited under different spray conditions on aluminum alloy substrates with a mirror finish. The influence of the in-flight particle temperature and velocity, carrier gas type, and carrier gas ratio on the solidification mechanism of molten droplets was investigated. Image analysis methods were employed to identify single splats from the morphology observed with field-emission scanning electron microscopy (FE-SEM). In addition, Er2O3 films were synthesized on an Al–Mg alloy (A5052) substrate using N2 or O2 as the carrier gas. When O2 was used as the carrier gas, 109-μm-thick films were deposited on the A5052 substrate. The cross-sectional porosity of the films was 3.8%. In contrast, films with 101-μm thickness were synthesized on the A5052 substrate when N2 was used as the carrier gas. The cross-sectional porosity of these films was 13.8%. The results showed that the carrier gas type (N2) and carrier gas ratio had a significant effect on the flattening behavior of the molten droplets. A spraying method combined with multidimensional modes is proposed to control the morphology of the splats. 相似文献
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目的 了解武汉市一般人群血清中全氟及多氟烷基化合物(PFASs)浓度,探索血清中PFASs浓度水平的影响因素。方法 以在武汉市某医院进行一般体检的人群为研究对象(n=67),通过超高效液相色谱-三重四级杆质谱(UPLC-TQ/MS)联用仪测定外周血清中12种PFASs浓度,采用多元线性回归分析方法分析一般人口学特征和血清中PFASs浓度的关联性。结果 武汉市一般人群血清中12种PFASs的平均浓度水平为11.60 ng/mL。全氟辛烷磺酸及其盐类(PFOS)和全氟辛酸及其盐类(PFOA)的贡献率较大,分别为45.03%和31.86%。男性人群血清中PFOS、PFOA、全氟己基磺酸(PFHxS)、全氟壬酸(PFNA)等主要化合物的浓度高于女性,其β值(95%可信区间)分别为0.708(0.313,1.104)、0.518(0.069,0.967)、0.724(0.388,1.059)和0.684(0.399,0.968)。同时,发现血清中PFOS、PFHxS、PFNA浓度和年龄呈正相关,其β值(95%可信区间)分别为0.062(0.042,0.081)、0.035(0.019,0.052)和0.030(0.016,0.045)。结论 性别和年龄对血清中PFASs浓度有影响,在进行人体PFASs暴露评估中应考虑这些因素。 相似文献
5.
Que Dan Nguyen Kosuke Kikuchi Basudev Maity Takafumi Ueno 《International journal of molecular sciences》2021,22(4)
Protein assemblies provide unique structural features which make them useful as carrier molecules in biomedical and chemical science. Protein assemblies can accommodate a variety of organic, inorganic and biological molecules such as small proteins and peptides and have been used in development of subunit vaccines via display parts of viral pathogens or antigens. Such subunit vaccines are much safer than traditional vaccines based on inactivated pathogens which are more likely to produce side-effects. Therefore, to tackle a pandemic and rapidly produce safer and more effective subunit vaccines based on protein assemblies, it is necessary to understand the basic structural features which drive protein self-assembly and functionalization of portions of pathogens. This review highlights recent developments and future perspectives in production of non-viral protein assemblies with essential structural features of subunit vaccines. 相似文献
6.
Risk factors at home for ocular, nasal, throat and dermal symptoms, headache, and fatigue were studied in a nationwide questionnaire survey in Sweden, the BETSI study in 2006. Totally, 5775 adults from a stratified random sample of multi-family buildings participated. Associations between home environment factors and weekly symptoms were analyzed by multi-level logistic regression. In total, 8.3% had ocular symptoms; 11.9% nasal symptoms; 7.1% throat symptoms; 11.9% dermal symptoms; 8.5% headache and 23.1% fatigue. Subjects in colder climate zones had more mucosal and throat symptoms but less fatigue and ocular symptoms. Rented apartments had poorer indoor environment than self-owned apartments. Those living in buildings constructed from 1961 to 1985 had most symptoms. Building dampness, mold and mold odor were risk factors, especially headache and ocular symptoms. Lack of mechanical ventilation system was another risk factor, especially for headache. Environmental tobacco smoke (ETS), electric radiators, and crowdedness were other risk factors. Oiled wooden floors, recent indoor painting, and new floor materials were negatively associated with symptoms. In conclusion, building dampness, mold, poor ventilation conditions, crowdedness, ETS, and emissions from electric radiators in apartments in Sweden can increase the risk of ocular, nasal, throat and dermal symptoms, headache, and fatigue. 相似文献
7.
Meng Zhu Xiaojuan Zhang Yanxia Su Yiguang Wang Yibo Wu Dan Yang Hao Wang Min Zhang Min Zhang Quan Chen Nanwen Li 《应用聚合物科学杂志》2019,136(15):47370
To improve the properties of diblock copolystyrene-based anion exchange membranes (AEMs), a series of AEMs with comb-shaped quaternary ammonium (QA) architecture (QA-PSm-b-PDVPPAn-xC where x denotes the number of carbon atoms in different alkyl tail chains and has values of 1, 4, 8, and 10 and C denotes carbon) were designed and synthesized via subsequent quaternization reactions with three different alkyl halogens (methyl iodide and N-alkane bromines (CH3[CH2] x-1Br where x = 4, 8, and 10). Compared with triblock analogues quaternized with methyl iodide in our previous research, QA-PSm-b-PDVPPAn-xC (x = 4, 8, and 10) AEMs are more flexible with the introduction of a long alkyl tail chain; this probably impedes crystallization of the rigid polystyrene-based main chain and induces sterically adjustable ionic association. An increase in the pendant alkyl tail chain length generally led to enhanced microphase separation of the obtained AEMs, and this was confirmed using small-angle X-ray scattering and atomic force microscopy. The highest conductivity (25.5 mS cm−1) was observed for QA-PS120-b-PDVPPA80-10C (IEC = 1.94 meq g–1) at 20 °C. Furthermore, the water uptake (<30%) and swelling ratio (<13.1%) of QA-PSm-b-PDVPPAn-xC AEMs are less than half of these corresponding values for their triblock counterparts. The QA-PS120-b-PDVPPA80-10C membrane retained a maximum stability that was as high as 86.8% of its initial conductivity after a 40-day test (10 M NaOH, 80 °C), and this was probably because of the steric shielding of the cationic domains that were surrounded by the longest alkyl tail chains. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47370. 相似文献
8.
Mengwei Liu Jin Zhao Shunzo Shimai Dan Han Jian Zhang Shiwei Wang 《Journal of the American Ceramic Society》2022,105(7):4632-4638
MgAl2O4 transparent ceramics were shaped by a commonly used polyacrylic acid (PAA), which acted as both dispersant and gelling agent. The spinel slurries were prepared by ball-milling MgAl2O4 powder, PAA, and water in an attrition mill. The gelling of slurries happened at room temperature in air atmosphere without any other organic additive. The gelling mechanism was the formation of chelates between Mg2+ and carboxyl groups (-COO−) of PAA. The frequency-based testing method was applied to investigate the gelling process of the as-prepared slurry. In addition, a novel in situ characterization method based on a modified indentation testing was invented to better understand the strengthening of the wet green body with time and to guide when demolding could be carried out. After sintering, transparent MgAl2O4 ceramics with high in-line transmittance were resulted. 相似文献
9.
Dan Liu Hongying Yang Jianhui Li Jiaqi Li Yizhe Dong Chuntian Yang Yuting Jin Lekbach Yassir Zhong Li David Hernandez Dake Xu Fuhui Wang Jessica A.Smith 《材料科学技术学报》2021,79(20):101-108
Titanium alloys possess excellent corrosion resistance in marine environments,thus the possibility of their corrosion caused by marine microorganisms is neglected.In this work,microbiologically influenced corrosion (MIC) of TC4 titanium alloy caused by marine Pseudomonas aeruginosa was investigated through electrochemical and surface characterizations during a 14-day immersion test.Results revealed that the unstable surface caused by P.aeruginosa resulted in exposure of Ti2O3 and severe pitting corrosion with maximum pit depth of 5.7 μm after 14 days of incubation.Phenazine-1-carboxy[ate (PCN),secreted by P.aeruginosa,promoted extracellular electron transfer (EET) and accelerated corrosion.Deletion of the phzH gene,which codes for the enzyme that catalyzes PCN production,from the P.aeruginosa genome,resulted in significantly decreased rates of corrosion.These results demonstrate that TC4 titanium alloy is not immune to marine MIC,and EET contributes to the corrosion of TC4 titanium alloy caused by P.aeruginosa. 相似文献
10.
Qinghe Wei Dan Wang Lili Zhang Liqing Zhao Bing Zhang Guoli Zhou Yafei Zhao 《Ceramics International》2021,47(17):24501-24510
Exploring inexpensive and active bifunctional electrocatalysts to produce hydrogen and oxygen from water at all pHs is highly desirable. Herein, we report a facile one-step method to prepare vertically aligned Co doped MoS2 nanosheets with extended interlayer distance on carbon cloth (Co–MoS2@CC) for full hydrolysis in both alkaline and acidic medium. Co–MoS2@CC exhibits long-term durability with overpotentials of 56.6 mV and 130 mV for hydrogen generation and 242 mV and 201 mV for oxygen production at 10 mA cm?2 in basic and acidic conditions, respectively. Moreover, we achieve low voltages of 1.585 V and 1.55 V in basic and acidic conditions respectively for the overall water splitting. We assume that such excellent property of Co–MoS2@CC may be ascribed to the uncovering of more active sites and high porosity resulted from Co doping, which boosts the conductivity and thus reduces MoS2 hydrogen adsorption free energy in HER, as well as benefits to catalytic active sites in OER. This one-step doping approach opens up new ways to regulate the intrinsic catalytic activity to catalyze total hydrolysis at all PHs. 相似文献