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101.
102.
以NaBH4作还原剂,TEOS为前体,采用反相微乳液法制得粒径50~100nm的Ag@SiO2核壳纳米粒子,其中Ag核为面心立方结构,壳层为无定形SiO2。考察催化剂加入的先后和微乳液R值(R=n水/n表面活性剂)对Ag@SiO2核壳纳米粒子形成的影响。用TEM、UV-Vis、XRD对纳米粒子的形貌及性质进行表征。结果表明:催化剂若先于TEOS加入,易得到Ag@SiO2核壳纳米粒子,随着R值的增加,Ag核的粒径变大,纳米粒子逐渐由单核变成多核。催化剂若后于TEOS加入,则形成负载型Ag/SiO2复合物。Ag核被SiO2壳包覆后的等离子共振吸收峰发生了微弱红移。而当壳厚80nm时,由于SiO2的散射作用,吸收峰会发生蓝移。 相似文献
103.
Yuhang Xing Ruyi Li Lu Xue Mianhong Chen Xuli Lu Zhihao Duan Wei Zhou Jihua Li 《International Journal of Food Science & Technology》2022,57(8):5268-5279
Mangiferin (MGF) is a phenolic compound isolated from mango, but its poor solubility significantly limits its use. In this study, MGF was embedded into the inner aqueous phase of W1/O/W2 emulsions. Firstly, the dissolution method of MGF was determined. MGF remained stable in solution with pH 13 at 30 min, and its solubility reached 10 mg mL−1. When the pH of MGF solutions was adjusted from pH 13 to pH 6, MGF did not immediately crystallise, providing sufficient time to construct the MGF-loaded W1/O/W2 emulsions. Subsequently, the MGF-loaded W1/O/W2 emulsions were constructed using polyglycerol polyricinoleate (PGPR) and calcium caseinate (CAS). The formation and stability of the W1/O/W2 emulsions were investigated. The MGF-loaded W1/O/W2 emulsions stabilised with 1% PGPR and 1% – 3% CAS exhibited a low viscosity, limited loading capacity, and poor stability. Conversely, the MGF-loaded W1/O/W2 emulsions stabilised by 3%PGPR–3%CAS exhibited optimal loading capacity (encapsulation efficiency = 95.31% and loading efficiency = 0.91%) and stability, which was attributed to the fact that high viscosity and gel state retarded the migration of inner aqueous phase. These results indicated that the W1/O/W2 emulsions stabilised by PGPR and CAS may be a potential alternative for encapsulating mangiferin. 相似文献
104.
Impact of iron encapsulation within the interior aqueous phase of water-in-oil-in-water emulsions on lipid oxidation 总被引:1,自引:0,他引:1
Iron (Fe3+) was encapsulated within the internal aqueous phase of water-in-oil-in-water (W/O/W) emulsions, and then the impact of this iron on the oxidative stability of fish oil droplets was examined. There was no significant change in lipid droplet diameter in the W/O/W emulsions during 7 days storage, suggesting that the emulsions were stable to lipid droplet flocculation and coalescence, and internal water diffusion/expulsion. The initial iron encapsulation (4 mg/100 g emulsion) within the internal aqueous phase of the water-in-oil (W/O) emulsions was high (>99.75%), although, a small amount leaked out over 7 days storage (≈10 μg/100 g emulsion). When W/O/W emulsions were mixed with fish oil droplets the thiobarbituric acid-reactive substances (TBARS) formed decreased (compared to fish oil droplets alone) by an amount that depended on iron concentration and location, i.e., no added iron < iron in external aqueous phase < iron in internal aqueous phase. These differences were attributed to the impact of W/O droplets on the concentration and location of iron and lipid oxidation reaction products within the system. 相似文献
105.
用机械合金化方法由元素粉末制备了Al1 - x Wx( x = 0 .1 ,0 .2 ,0 .5 ,0 .9) 合金。用X 射线衍射法对球磨后的粉末进行了分析, 并用扫描电镜和透射电镜观察了形貌并研究了晶相结构。结果表明, 球磨后Al 在W 中的固溶度大大扩展, 但球磨到250h 该系统仍未形成非晶; Al0 .5 W0 .5 粉末经250 h球磨后出现一结构为体心四方的新相。热力学计算表明该系统不能形成非晶 相似文献
106.
107.
M.F. Cardinal P.A. Castro J. Baxi H. Liang F.J. Williams 《Surface & coatings technology》2009,204(1-2):85-90
Ni–W–MoS2 composite coatings were obtained by pulse plating from a Ni–W electrolyte containing suspended MoS2 particles. The coating composition, morphology, crystalline structure, microhardness and frictional behavior were studied as a function of MoS2 concentration. The results obtained in this study indicate that co-deposited lubricant particles strongly influenced the composite Ni–W coating properties. It was found that increasing co-deposited MoS2 diminished tungsten content in the coating and consequently increased the average grain size. Ni–W nanostructured coatings with high MoS2 content have a porous sponge-like structure, high surface roughness and irregular frictional behavior. However, the friction coefficient of Ni–W coatings is reduced to half its value with low MoS2 content. 相似文献
108.
109.
采用晶粒表面的萃取碳复型技术,观察研究了钛在一种具有大晶粒尺寸的高温合金中的晶界析出行为-晶界(Ti,Mo)C脆性包膜的形成和效应;不同含量的铌对一种高温合金晶界析出相类型、形貌分布、成分和数量的影响;分析讨论了钨和钼等元素对某些高温合金晶界碳化物和硼化物的析出行为存在的直接作用和间接作用。 相似文献
110.