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1.
Bin Zhang Alexander K. Nguyen Roger J. Narayan Jie Huang 《Journal of the American Ceramic Society》2022,105(3):1821-1840
Novel inks were formulated by dissolving polycaprolactone (PCL), a hydrophobic polymer, in organic solvent systems; polyethylene oxide (PEO) was incorporated to extend the range of hydrophilicity of the system. Hydroxyapatite (HAp) with a weight ratio of 55–85% was added to the polymer-based solution to mimic the material composition of natural bone tissue. The direct ink writing (DIW) technique was applied to extrude the formulated inks to fabricate the predesigned tissue scaffold structures; the influence of HAp concentration was investigated. The results indicate that in comparison to other inks containing HAp (55%, 75%, and 85%w/w), the ink containing 65% w/w HAp had faster ink recovery behavior; the fabricated scaffold had a rougher surface as well as better mechanical properties and wettability. It is noted that the 65% w/w HAp concentration is similar to the inorganic composition of natural bone tissue. The elastic modulus values of PCL/PEO/HAp scaffolds were in the range of 4–12 MPa; the values were dependent on the HAp concentration. Furthermore, vancomycin as a model drug was successfully encapsulated in the PCL/PEO/HAp composite scaffold for drug release applications. This paper presents novel drug-loaded PCL/PEO/HAp inks for 3D scaffold fabrication using the DIW printing technique for potential bone scaffold applications. 相似文献
2.
利用水力空化过程产生局部的高温、高压、高射流以及强大的剪切力等极端化学物理条件改质处理沙特重质原油,试验结果表明:沙特重质原油经过水力空化改质后粘度由13.61降低至7.22mm2/s,残碳由7.16%降低至6.48%,实沸点蒸馏后减压渣油降低1个百分点。进一步采用APPI FT-IR MS、XRD、FT-IR、SEM和粒度分布等技术研究了水力空化改质对沙重原油分子组成,沥青质团聚体微晶结构、沥青质胶束粒径分布、沥青质官能团、沥青质形貌等方面的影响,从分子角度阐述空化改质重油的机理。研究结果表明:水力空化改质后沙重原油分子量分布、芳烃类化合物缔合作用变小;沥青质对低DBE化合物吸附性能降低;沥青质团聚体微晶结构更加松散;沥青质胶束粒度分布降低;沥青质分子相互团聚作用力减弱。进一步考察了水力空化改质前后减压渣油延迟焦化性能,改质处理后焦炭产率降低1.85个百分点,液体收率和气体产率分别增加1.52和0.33个百分点,水力空化改质对沥青质性质、结构特点的改善能够有效的提高其加工性能。 相似文献
3.
Fine-grained few-shot learning is a difficult task in image classification. The reason is that the discriminative
features of fine-grained images are often located in local areas of the image, while most of the existing few-shotlearning image classification methods only use top-level features and adopt a single measure. In that way, the localfeatures of the sample cannot be learned well. In response to this problem, ensemble relation network with multi-level measure (ERN-MM) is proposed in this paper. It adds the relation modules in the shallow feature space tocompare the similarity between the samples in the local features, and finally integrates the similarity scores from thefeature spaces to assign the label of the query samples. So the proposed method ERN-MM can use local details andglobal information of different grains. Experimental results on different fine-grained datasets show that the proposedmethod achieves good classification performance and also proves its rationality. 相似文献
4.
射频电感耦合等离子体(ICP)在实际放电过程中,线圈的构型、电源参数、气压等外部工质条件的变化均会对结果产生较大影响,依靠实验很难得到多外部条件对ICP参数分布的影响机理和规律,因此需要结合仿真和实验的方法进行分析。该文通过建立感性线圈的电磁学有限元模型,分析不同线圈构型下射频电磁场在等离子体内部的空间分布,研究放电参数(线圈构型、功率大小)对等离子体分布影响和E-H模型下放电形态的跳变过程,并观察进入稳定H模式后电源参数的变化规律,为等离子体源的小型化工程应用提供理论基础。实验和仿真计算结果表明:不同线圈匝数在不同功率条件下,电磁场强度变化对等离子功率吸收和功率耦合有较大影响;当工作气压在0~20Pa时,ICP的电子密度呈轴对称分布,随着放电功率、气压的增大,等离子体吸收的功率和电离度也随之增加,其电子密度相应地增大,放电功率的增加会使得环状的等离子体区域随之扩大,在轴向、径向上的分布呈先逐渐增大而后在靠近腔室壁面区域迅速下降。 相似文献
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6.
Scientometrics - Governments typically formulate sets of policies to guide the direction of scientific research. And the possible effects of these policies on scientific research have been... 相似文献
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8.
Xuejie Li Yaqing Wen Jian Zhang Dongyun Ma Jie Zhang Yanxia An Xiaoyan Song Xiujuan Ren Weifeng Zhang 《International Journal of Food Science & Technology》2022,57(3):1544-1553
The effects of non-thermal plasma (NTP) on the physicochemical properties of wheat flour and the quality of fresh wet noodles ( FWN) were investigated. The results showed that NTP effectively decreased the total plate count (TPC), yeast and mould count (YMC) and Bacillus spp. in wheat flour. Wet gluten contents and the stability time reached the maximum when treated for 20 s. The viscosity of starch increased significantly after treatment due to the increased of damaged starch. The contents of secondary structure were altered to some extent, which was because that the ordered network structure of gluten protein broken. Furthermore, compared with the control, texture properties of FWN were enhanced significantly at 20 s, and the darkening rate of FWN was greatly inhibited due to the low polyphenol oxidase (PPO) activity. Consequently, the most suitable treatment was 500 W for 20 s, providing a basis for the application of NTP in flour products. 相似文献
9.
Fire Technology - The current research on individual risks mainly focuses on the individual risk considering a single fire or the spatial distribution of multiple fires. It is more realistic to... 相似文献
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