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41.
K. Balamurugan S. Sankar U. S. Hareesh K. G. K. Warrier 《Materials and Manufacturing Processes》2018,33(4):405-413
In this work, lanthanum phosphate with a 20% yttria (LaPO4/Y2O3) composite prepared by an Aqueous Sol–Gel process is machined using an Abrasive Water Jet Machine (AWJM). The machinability of this composite is studied by varying the input parameters namely Jet Pressure (JP), Stand-Off Distance (SOD), and Traverse Speed (TS) on Surface finish. Garnet of 80 mesh size is used as an abrasive with a flow rate of 85?g/min. The microstructural characterization study reveals the presence of new element YPO4. This element enhances the machinability and reduced porosity in the composite. Microscopy examinations on the machined surface reveals that partial overlapping at low JP, poor surface finish at high JP and SOD, forged deficiency at maximum SOD and TS. The minimum levels of all input parameters are influenced to obtain acceptable Ra. Atomic Force Microscopy (AFM) on the kerf surface shows micro wear track and peaks. The Multiple Regression Analysis (MRA) is developed for Ra to check the adequacy. From the Analysis of Variance (ANOVA), SOD has a significant effect on Ra with a contribution of 53%. The influence of JP and TS on Ra is found to be 31% and 15%, respectively. 相似文献
42.
Varinder Singh Richa Shri Pawan Krishan Inder Pal Singh Purvi Shah 《Journal of food science》2020,85(11):4009-4017
The antioxidant-mediated neuroprotective effect of Allium cepa outer scale extract (ACE) in mice with cerebral ischemia-reperfusion (I-R) injury was demonstrated in our earlier work. The current investigation aimed at establishing the bioactive component(s) responsible for this activity. Thus ACE was fractionated into ethyl acetate (EF) and aqueous (AF) fractions. These fractions were evaluated against cerebral I-R injury in mice. I-R injury in mice was induced by bilateral common carotid artery occlusion followed by 24 hr reperfusion. Memory, sensorimotor functions, cerebral infarct size, and oxidative stress were measured to address the neuroprotective mechanism of test substances. EF showed marked improvement of memory and sensorimotor functions by reducing brain oxidative stress and infarct size in mice after I-R injury. The bioactive EF was subjected to chromatographic (HPLC-PDA, HPLC-MS, preparative HPLC) and spectroscopic studies to isolate and identify the neuroprotective compounds. This lead to separation of three components, namely quercetin, quercetin 4′-O-glucoside, and the remaining fraction, from EF. The separated components were biologically evaluated. These components showed improvement in mice with I-R injury. But, EF displayed more marked neuroprotective effects as compared to the isolated components. The distinct neuroprotective outcome of EF may be credited to the synergistic action of compounds present in EF. Further studies such as evaluation of neurotoxic effects and other possible neuroprotective mechanisms are required to develop EF as a neuroprotective drug. 相似文献
43.
Tomoko Okuyama Jun Shirakawa Kazuki Tajima Yoko Ino Heidrun Vethe Yu Togashi Mayu Kyohara Ryota Inoue Daisuke Miyashita Jinghe Li Nozomi Goto Taiga Ichikawa Shingo Yamasaki Haruka Ohnuma Rie Takayanagi Yayoi Kimura Hisashi Hirano Yasuo Terauchi 《International journal of molecular sciences》2020,21(21)
44.
Sammar Minallah Erum Pervaiz M. Usman Yousaf M. Bilal Khan Niazi Liu Honghong 《分离科学与技术》2020,55(15):2623-2641
ABSTRACT Current health situations have instigated increased frequency of taking antibiotics for cure of infections but this amplified use is posing threats to environment. This research is focused to remove Tetracycline (TC), an antibiotic from water, using an advanced nanohybrid that compact the properties of adsorbent and photocatalyst. Compared to conventional methods for remediation of TC, large surface area (452 m2g?1) adsorbent photocatalyst hybrid (APH) g-C3N4/α-MoO3/ZIF-67 (CMZ) have found much effective as 97% degradation of TC is observed in 110 min with 0.1 g of APH. Increasing g-C3N4 in the hybrids has improved percent degradation of TC molecules. CMZ-3 is found as a potential candidate for water treatment. 相似文献
45.
Huiping Shao Xinding Yu Zhinan Zhang Tao Lin Jiang Peng Aiyuan Wang Shuwen Liu Manjian Zhao 《International Journal of Applied Ceramic Technology》2020,17(6):2762-2767
Porous CaSiO3-CaSO4 composite scaffolds were successfully prepared by 3D gel-printing (3DGP) technology in this study. In order to further improve the degradation performance of pure CaSiO3 scaffolds, the effect of different CaSO4 doping contents on CaSiO3-CaSO4 composite scaffolds was studied. The results show that when the porous composite scaffolds were placed in simulated body fluid (SBF) for 5 weeks, the weight loss rate was 2.41% (CaSiO3-1%CaSO4), 3.97% (CaSiO3-3%CaSO4), 4.18% (CaSiO3-5%CaSO4), 6.87% (CaSiO3-7%CaSO4), and 12.93% (CaSiO3-9%CaSO4), respectively, which could be concluded that CaSO4 doping has a significant effect on improving the biodegradability of CaSiO3 scaffolds. And CaSO4 doping can also effectively improve the compressive strength of composite scaffolds and that of CaSiO3-3%CaSO4 composite scaffolds was tested as 54.67 MPa, and the shrinkage rate of porous composite scaffolds was nearly 11.4%, which meets the application requirements of bone repairing engineering. 相似文献
46.
Han Yan Gu Yi Chen Lei Li Bing Liu Xiang Ming Chen 《International Journal of Applied Ceramic Technology》2020,17(2):790-796
SrLa[Ga1−x(R0.5Ti0.5)x]O4 (R = Mg, Zn) ceramics were prepared by a standard solid state sintering method. The single-phase ceramics with K2NiF4-type layered perovskite structure and I4/mmm space group were obtained, indicating that SrLa(R0.5Ti0.5) and SrLaGaO4 can form the unlimited solid solutions. With increasing x for R = Mg and Zn, εr increases monotonously, the Qf value first increases and then decreases, while τf increases from a negative to a positive value. The optimized microwave dielectric properties were obtained as following: εr = 23.3, Qf = 89 400 GHz, τf = −0.8 ppm/°C for SrLa[Ga0.6(Mg0.5Ti0.5)0.4]O4 and εr = 23.3, Qf = 76 200 GHz, τf = 0.2 ppm/°C for SrLa[Ga0.7(Zn0.5Ti0.5)0.3]O4, indicating that the present solid solution ceramics are the promising candidates as microwave resonator materials for the telecommunication applications. 相似文献
47.
《Ceramics International》2020,46(1):251-257
X-ray photons attenuation characteristics for the two tellarite based glasses Bi2O3– B2O3– TeO2– TiO2 and PbO–ZnO–TeO2–B2O3 have been investigated at dental diagnostic energies (between 30-80 keV) using Geant4 code and WinXcom software. The correlation coefficient (R2) is utilized to evaluate the extent to which Geant4 results are related to the WinXcom data. For the both series, R2 is close to 1 for all samples and this implies a perfect degree of association between the Geant4 and WinXcom data. The linear attenuation coefficient is proportionally increased with addition of TeO2 in both series, which implies that there is a decreasing tendency in the X-ray photon transmission corresponding with an increase in the TeO2 content in the glasses. The half value layer (HVL) decreases as the density increases and this decreasing is very notable at 70 and 80 keV. The maximum HVL for all samples occurs at 80 keV and this implies that the HVL gradually increases as the energy of the X-ray photons increase. Also, the increment of TO2 in the glasses (in both systems) leads to reduce the mean free path and BiTeTi6 and PbTeB6 samples have the lowest MFP. The MFP for both systems was compared with three heavy concretes and the comparison revealed that the selected systems can be utilized to fabricate protection masks used during diagnostic radiation of the head or oral cavity. 相似文献
48.
49.
为提高EA4T车轴钢的表面硬度和耐磨性能,采用激光淬火对调质态车轴进行表面改性。利用扫描电镜、显微硬度计、纳米压痕仪等对激光淬火层的微观组织、相变层深度和硬度进行了详细的表征。结果表明:EA4T车轴钢表面经过不同工艺激光淬火后,相变层内的淬火组织主要由细小的板条马氏体和粒状贝氏体组成,其深度根据工艺不同从100 μm到800 μm不等,并呈现随淬火功率的增加和扫描速度减小,相变层深度逐渐增加的趋势。淬火相变层区域内,车轴钢的显微硬度基本保持在450 HV0.2左右,约为基体硬度的2倍,耐磨性显著提高。由于淬火道次之间搭接的原因,淬火层呈现波形分布,其中波谷马氏体含量高于波峰位置,因此其硬度明显高于波峰处。 相似文献
50.
为研究在电流辅助成形时脉冲电流的电流密度、占空比和脉冲频率3个因素对6016-T4铝合金板材力学性能的影响规律,设计了3因素5水平的正交实验。实验表明,对6016-T4铝合金力学性能影响的主次因素是:电流密度>占空比>脉冲频率。在此基础上,选用主次2个因素,即电流密度和脉冲频率,使用控制变量法进行进一步的实验研究。实验结果表明,电流密度对6016-T4铝合金力学性能影响较大,改变电流密度的同时带来了明显的焦耳热效应,该效应对材料有明显的软化作用,降低了材料的流动应力,但是,同时也降低了铝合金板的伸长率,这是因为过大的电流密度加剧了试样的主应变演化,进而促进了试样的断裂。而脉冲频率的变化对6016-T4铝合金板材的力学性能影响很小,这也印证了正交实验的结论。 相似文献