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1.
For the purpose of developing biodegradable magnesium alloys with suitable properties for biomedical applications, Mg–Zn–Ca–Cu metallic glasses were prepared by copper mold injection methods. In the present work, the effect of Cu doping on mechanical properties, corrosion behavior, and glass-forming ability of Mg66Zn30Ca4 alloy was studied. The experimental findings demonstrated that the incorporation of Cu decreases the corrosion resistance of alloys, but increases the microhardness and degradation rate slightly. However, the addition of a trace amount of Cu can make the samples have antibacterial properties. Therefore, Mg–Zn–Ca–Cu has great advantages in clinical implantation and is the potential implant material. 相似文献
2.
3.
Zhuang Tang Yuwei Huang Kangning Wu Jianying Li 《Journal of the European Ceramic Society》2018,38(4):1569-1575
Significantly enhanced breakdown field of 24.52 kV cm?1 as well as noteworthy nonlinear coefficient of 8.11 and low dielectric loss of 0.077 were obtained in Ca0.6Sr0.4Cu3Ti4O12 ceramic. It was proved from impedance spectra that improved breakdown field was attributed to enhanced grain boundary resistance and elevated Schottky barrier height, which was further found resulting from reduced donor densities in C-V measurements. In addition, it was found that the activation energy originated from oxygen vacancies was increased, indicating the generation of oxygen vacancies was suppressed. Since oxygen vacancies acted as donors in depletion layers, it is reasonable to deduce that the reduced donor density was mainly ascribed to the decreased oxygen vacancies. In conclusion, maximum integrated action of strong solid solution effect and weak Sr-stretching effect was achieved when Sr/Ca ratio is 40/60, leading to greatly elevated potential barrier height and enhanced breakdown field consequently. 相似文献
4.
《Calphad》2019
Mg–Zn–Ca alloys are representative Mg alloys with high formability at room temperature. Their high formability is thought to be related to slip, twinning, and recrystallization of the alloys, but the detailed mechanisms have not yet been clarified. To enable atomistic simulations for investigating those behaviors, an interatomic potential for the Mg–Zn–Ca ternary system was developed. The development was based on the second nearest-neighbor modified embedded-atom method formalism, combining previously developed Mg–Zn and Mg–Ca potentials with the newly developed Zn–Ca binary potential. The Zn–Ca and Mg–Zn–Ca potentials reproduce structural, elastic, and thermodynamic properties of compounds and solution phases of relevant alloy systems in reasonable agreement with experimental data, first-principles and CALPHAD calculations. The applicability of the developed potentials is demonstrated through calculations of the effects of Zn and Ca solutes on the generalized stacking fault energy for various slip systems, segregation energy on twin boundaries, and volumetric misfit strain. 相似文献
5.
Angiotensin I‐converting enzyme inhibitory and Ca‐binding activities of peptides prepared from tuna cooking juice and spleen proteases 下载免费PDF全文
Jirawadee Kasiwut Wirote Youravong Pittaya Adulyatham Nualpun Sirinupong 《International Journal of Food Science & Technology》2015,50(2):389-395
Tuna cooking juice is a by‐product from the tuna canning industry. In this study, tuna cooking juice was hydrolysed by proteases extracted from the spleen. Tuna cooking juice showed the highest ACE inhibitory and Ca‐binding activities after hydrolysis for 270 and 180 min, respectively. The hydrolysate was further fractionated by ultrafiltration. The permeate exhibited highest ACE inhibitory and Ca‐binding activities when passed through 1 and 5 kDa cut‐off membranes, respectively. Gel filtration chromatography was used to determine the MW of bioactive peptides that exhibited highest ACE inhibitory and Ca‐binding activities. Those peptides that exhibited highest ACE inhibitory and Ca‐binding activities were the MW range of 238–829 Da and 1355–1880 Da, respectively. These results suggest that the tuna cooking juice and the spleen protease extract are a potential source of bioactive peptides that can be utilised as bioactive ingredients in functional food and nutraceuticals. 相似文献
6.
AbstractBa0.95Ca0.05Ti1-xZrxO3 (BCTZO) ceramics were prepared by a solid state reaction method. The samples were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and X-ray absorption near edge structure (XANES). The ceramics exhibit a pure perovskite structure. The average grain size gradually decreases with increasing Zr concentration. XANES results indicate that the intensities of pre-edge peaks dropped with increasing Zr concentration. The BCTZO ceramic of x?=?0.05 has the optimum electrical properties with the maximum dielectric constant (ε'm), remanent polarization (2Pr), coercive electric field (2Ec) and piezoelectric charge constant (d33) of 7,244, 12.54 (μC/cm2), 5.29 (kV/cm) and 288 (pC/N), respectively. 相似文献
7.
Xian Yang Yu Zhang Xuejie Zhang Jian Chen Haisen Huang Dongsheng Wang Xirong Chai Gening Xie Maxim S. Molokeev Haoran Zhang Yingliang Liu Bingfu Lei 《Journal of the American Ceramic Society》2020,103(3):1773-1781
The red emission with suitable peak wavelength and narrow band is acutely required for high color rendering index (CRI) white LEDs without at the cost of the luminous efficacy. Herein, the Li2Ca2Mg2Si2N6:Eu2+ red phosphor was prepared with facile solid-state method using Ca3N2, Mg3N2, Si3N4, Li3N, and Eu2O3 as the safety raw materials under atmospheric pressure for the first time, which shows red emission peaking at 638 nm with full width at half maximum (FWHM) of 62 nm under blue light irradiation and becomes the desired red phosphor to realize the balance between luminous efficacy and high CRI in white LEDs. The morphology, structure, luminescence properties, thermal quenching behavior, and chromaticity stability of the Li2Ca2Mg2Si2N6:Eu2+ phosphor are investigated in detail. Concentration quenching occurs when the Eu2+ content exceeds 1.0 mol%, whereas high-temperature photoluminescent measurements show a 32% drop from the room-temperature efficiency at 423 K. In view of the excellent luminescence performances of Li2Ca2Mg2Si2N6:Eu2+ phosphor, a white LEDs with CRI of 91 as a proof-of-concept experiment was fabricated by coating the title phosphor with Y3Al5O12:Ce3+ on a blue LED chip. In addition, the potential application of the title phosphor in plant growth LED device was also demonstrated. All the results indicate that Li2Ca2Mg2Si2N6:Eu2+ is a promising red-emitting phosphor for blue LED-based high CRI white LEDs and plant growth lighting sources. 相似文献
8.
利用Gleeble3500热模拟试验机研究了Ca对Mg-Gd-Y-Zn-Zr合金在变形温度573~723 K,应变速率0.001~1 s-1的热变形行为及热加工性能的影响。结果表明:Ca增大了合金的流变应力及变形激活能,扩宽了加工安全区及最佳加工区范围,但降低了最大功率耗散因子及动态再结晶程度。结合激光共聚焦显微镜分析了合金热压缩后组织,验证了热加工图的准确性,并制定了合理的热加工工艺,Mg-Gd-Y-Zn-Zr合金的最佳加工区域为:应变速率0.001~0.01 s~(-1),温度623~723 K。根据最佳加工工艺参数获得了表面质量良好,无变形缺陷的等温锻造合金。 相似文献
9.
Shao-Fang Li Zhen-Yi Gu Jin-Zhi Guo Xian-Kun Hou Xu Yang Bo Zhao Xing-Long Wu 《材料科学技术学报》2021,78(19):176-182
In recent years,sodium-ion batteries(SIBs)have been considered as one of the most promising alterna-tives to lithium-ion batteries(LIBs).Here,a new Na-super-ionic conductor(NASICON)cathode material NaFe2PO4(SO4)2 is successfully prepared through solid state method for SIBs.While the poor electronic conductivity of iron-based materials results in its poor rate and cycle performance.Then the electro-chemical is effectively promoting via Ca2+doping.Na0.84Ca0.08Fe2PO4(SO4)2 have achieved considerable electrochemical properties.The first discharge specific capacity is 121.6mAhg-1 at 25mAg-1 with the voltage platform(~3.1 V)corresponding to Fe2+/3+.After 100 cycles,the capacity retention is 55.1%.The excellent electrochemical performance is caused by some Na+is substituted by Ca2+and leading to the fast sodium kinetics,which is well proved by the powder X-ray diffraction pattern and well corresponding to the galvanostatic intermittent titration technique and cyclic voltammetry testing result(the diffusivity values are around at 10-12 cm2 s-1). 相似文献
10.
采用燃烧法合成出Ca12Al14O33∶Eu2+,Nd3+靛蓝色长余辉发光粉.利用XRD和FE-SEM对产物的物相结构和形貌进行了表征,用激发光谱、发射光谱和余辉衰减曲线对样品的发光性能进行了分析.通过正交试验设计,以余辉时间为指标,研究了Eu2+的掺杂量、Nd3+的掺杂量、H3B03的用量以及尿素的用量对制备条件的影响.研究结果表明:最优化方案制备的Ca12Al14O33∶Eu2+,Nd3+长余辉发光粉的发射光谱呈宽发射谱带,波长范围为390~530 nm,发光峰值位于443 nm,余辉时间长达3240 s. 相似文献