Journal articles: 'Nano-sized pores'

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Song, Panqi, Xiaoqing Tu, Liangfei Bai, Guangai Sun, Qiang Tian, Jian Gong, Guiyu Zeng, Liang Chen, and Lili Qiu. "Contrast Variation Small Angle Neutron Scattering Investigation of Micro- and Nano-Sized TATB." Materials 12, no. 16 (August 16, 2019): 2606. http://dx.doi.org/10.3390/ma12162606.

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Small angle neutron scattering (SANS) with contrast variation was used to characterize the fractal behavior and embedded porosity of micro/nano-sized 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) crystallites, gauging the effects of particle sizes on the microstructural features. Scattering results reveal that the external surface of micro-sized TATB crystallites are continuous and smooth interfaces and their internal pores display a surface fractal structure (surface fractal dimension 2.15 < DS < 2.25), while the external surface of nano-sized TATB particles exhibit a surface fractal structure (surface fractal dimension 2.36 < DS < 2.55) and their internal pores show a two-level volume fractal structure (large voids consist of small voids). The voids volume fraction of nano-sized TATB particles are found increased distinctively when compared with micro-sized TATB particles on length scale between 1 nm and 100 nm. Specific surface areas are also estimated based on Porod law method, which are coincident with Brunauer-Emmett-Teller (BET) measurements. The contrast variation technique distinguishes the information of internal voids from external surface, suggesting SANS is a powerful tool for determining the microstructural features, which can be used to establish the relationship between microstructures and properties of micro/nano-energetic materials.

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Lee, K. J., Jong Wan Park, Jae Kyo Yang, Kee Sung Lee, and Yong Ho Choa. "Synthesis and Application of Nano Porous La_0.6Sr_0.4CoO_3-δ on an Oxygen Separation Membrane." Key Engineering Materials 317-318 (August 2006): 709–12. http://dx.doi.org/10.4028/www.scientific.net/kem.317-318.709.

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As the oxygen permeation flux of La0.7Sr0.3Ga0.6Fe0.4O3-δ (LSGF) membranes is lower than commercial membranes, we coated the nano porous La0.6Sr0.4CoO3-δ (LSC) particles to enhance the oxygen permeation flux. The nano porous LSC particles were synthesized in an advanced process to increase the volume fraction of nano pores by ultrasonic spray pyrolysis. The synthesized LSC particles consisted of nano sized primary particles and pores. They also had remarkably high surface area (22 m2/g). It was found that the LSGF membrane coated by the nano porous LSC resulted in significant improvement in the oxygen permeability.

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Lee, Soo Young, and Chong Soo Han. "Nano Filter from Sintered Rice Husk Silica Membrane." Journal of Nanoscience and Nanotechnology 6, no. 11 (November 1, 2006): 3384–87. http://dx.doi.org/10.1166/jnn.2006.016.

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A nano filter showing the Knudsen flow was demonstrated by a modification of a membrane constructed from rice husk silica. The membrane was prepared by pressing and sintering micron sized rice husk silica with 4 nm pores. The membrane showed a permeability of 5.2 × 10−8 mol m−1 sec−1 Pa−1 for H2 and ratios of gas permeability 2.1 and 3.2 for k(H2)/k(CH4) and k(H2)/k(CO2), respectively. When the membrane was treated by filtration of ∼100 nm sized rice husk silica particles, the permeability decreased to 4.9 × 10−8 mol m−1 sec−1 Pa−1 and the ratios increased to 2.2 and 3.4. In the case of the membrane after treatments with the dispersion and chemical deposition of tetraethylorthosilicate (TEOS), the corresponding permeability and ratios of the membrane were 1.8 × 10−8 mol m−1 sec−1 Pa−1, and 2.9 and 4.5, respectively. From the change of the ratio of gas permeability for the membrane with modifications, it is suggested that ∼100 nm sized rice husk silica particles pack the large pores among the micron sized rice husk silica particles while the chemical deposition of tetraethylorthosilicate (TEOS) reveals the gas flow through 4 nm pores in the rice husk silica by blocking large pores.

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Feng, Yan, Yuliang Zhang, Guixiang Du, Jingbo Zhang, Miao Liu, and Xiaohui Qu. "Li2S–Embedded copper metal–organic framework cathode with superior electrochemical performance for Li–S batteries." New Journal of Chemistry 42, no. 16 (2018): 13775–83. http://dx.doi.org/10.1039/c8nj02370k.

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Zhang, Haobin, Hongfan Wang, Jinjiang Xu, Jie Sun, and Xiaolin Wang. "Investigation on the Evolution of Nano-Scale Defects of CL-20 Crystals under Thermal Treatment by Wide/Small-Angle X-ray Scattering." Materials 15, no. 12 (June 15, 2022): 4258. http://dx.doi.org/10.3390/ma15124258.

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Nano-scale crystal defects extremely affect the security and reliability of the explosive charges of weapons. In order to understand the evolution of nano-scale defects of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaaza-isowurtzitane (CL-20) explosive crystals under thermal treatments, the specific surface, volume fraction and size distribution of the nano-scale defects were studied by using Wide Angle X-ray Scattering (WAXS) and Small Angle X-ray Scattering (SAXS) during the temperature range from 30 °C to 200 °C. The results showed that the number and size of the pores in CL-20 powder did not change significantly during the heating process before phase transformation (30–160 °C). At 170 °C, CL-20 began to convert from ε- to γ- phase, and the specific surface and volume fraction of the nano-scale defects increased significantly. Further investigation of the pore size distribution showed that the number of pores with a small size (radius 9–21 nm) changed particularly significantly, resulting from the cracking of the CL-20 crystal powder during phase transition. At 200 °C, the phase transition was completed and γ-CL-20 was created, and the small-sized pores gradually grew into medium-sized (radius 21–52 nm) pores over time when the temperature was fixed at 200 °C.

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Fu, Lvping, Huazhi Gu, Ao Huang, Yongshun Zou, and Hongwei Ni. "Enhanced corrosion resistance through the introduction of fine pores: Role of nano-sized intracrystalline pores." Corrosion Science 161 (December 2019): 108182. http://dx.doi.org/10.1016/j.corsci.2019.108182.

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Itoi, Hiroyuki, Hiroyuki Muramatsu, and Michio Inagaki. "Constraint spaces in carbon materials." RSC Advances 9, no. 40 (2019): 22823–40. http://dx.doi.org/10.1039/c9ra03890f.

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Nano-sized pores in carbon materials give certain constraints to the encapsulated materials by keeping them inside. We review recent experimental results related to these constraint spaces and the spaces created by carbon coating.

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Matlahov, Irina, Yasmin Geiger, and Gil Goobes. "Trapping RNase A on MCM41 pores: effects on structure stability, product inhibition and overall enzymatic activity." Phys. Chem. Chem. Phys. 16, no. 19 (2014): 9031–38. http://dx.doi.org/10.1039/c3cp55520h.

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Leem, Jae-Young, Su Min Jeon, Min Su Kim, Min Young Cho, Hyun Young Choi, Kwang Gug Yim, Ghun Sik Kim, et al. "Fabrication of Porous ZnO Nanorods with Nano-sized Pores and Their Properties." Journal of the Korean Physical Society 57, no. 6 (December 15, 2010): 1477–81. http://dx.doi.org/10.3938/jkps.57.1477.

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Li, Zhonghao, Jianling Zhang, Jimin Du, Buxing Han, and Jiaqiu Wang. "Preparation of silica microrods with nano-sized pores in ionic liquid microemulsions." Colloids and Surfaces A: Physicochemical and Engineering Aspects 286, no. 1-3 (September 2006): 117–20. http://dx.doi.org/10.1016/j.colsurfa.2006.03.011.

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11

Gao, Pei-Hu, Sheng-Cong Zeng, Can Jin, Bo Zhang, Bai-Yang Chen, Zhong Yang, Yong-Chun Guo, et al. "Thermal Conductivity of Multi-Sized Porous Thermal Barrier Coatings at Micro and Nano Scales after Long-Term Service at High Temperatures." Coatings 11, no. 10 (September 29, 2021): 1183. http://dx.doi.org/10.3390/coatings11101183.

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Thermal barrier coatings with multi-sized porous structure at micro and nano scales were prepared with hollow spherical YSZ powders and polypropylene powders through atmospheric plasma spraying. The thermal conductivities of the multi-sized thermal barrier coatings after a long-term serving at high temperature were tested through laser flash heating method. Meanwhile, the physical models of thermal barrier coatings with multi-sized porous structure at micro and nano scales were constructed through Ansys Workbench. The evolutions of thermal conductivity of thermal barrier coatings with multi-sized pores after long-term service at 1100 °C were investigated through computation. It was found that the thermal conductivity of the coating increased with the extension of the serving time. When the serving time reached 60 days, the thermal conductivity of the coating tended to be stable and close to the compacted bulk. The computational results were consistent with the tested ones, which could be helpful to explain the thermal conducting evolution in thermal barrier coatings with multi-sized porous structure at nano and micro scales after long-term serving at high temperature.

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Zhu, Hongjian, Yiwen Ju, Cheng Huang, Yu Qi, Liting Ju, Kun Yu, Wuyang Li, Xin Su, Hongye Feng, and Peng Qiao. "Tectonic and Thermal Controls on the Nano-Micro Structural Characteristic in a Cambrian Organic-Rich Shale." Minerals 9, no. 6 (June 10, 2019): 354. http://dx.doi.org/10.3390/min9060354.

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Until recently, the characteristics of nano-microscale structures in the naturally deformed, overmature, marine shales were poorly known. Thermally overmature Lujiaping shales in the complex tectonic area of the northeast part of the upper Yangtze area, China have experienced strong tectonic deformation and are considered as potentially important strata for shale gas exploration. Naturally deformed samples from the main source rocks are selected from the Lower Cambrian Lujiaping Formation in the Dabashan Thrust-fold Belt to investigate nanometer- to micrometer-sized structures. A combination of scanning electron microscope (SEM), low-pressure nitrogen adsorption (LPNA), and low-field nuclear magnetic resonance (NMR) suggests that the pore types are dominantly fracture-related pores with a lesser abundance of mineral-hosted pores. These two pore types account for the 90% of total pore space. Organic matter (OM)-hosted pores are rare and make up a small part of the pore systems (less than 10%) due to high thermal maturity and intensive tectonic compression. Overall, the Lujiaping deformed, overmature samples have abundant nanometer- to micrometer-sized inorganic pores. High-resolution SEM images provide direct evidence of the formation of nano- and microsized structures such as OM–clay aggregates and silica nanograins. OM–clay aggregates are commonly observed in samples, which also exhibit abundant open microfractures and interparticle pores. Quartz can occur as silica nanograins and botryoids typically 20–100 nm in size, which may influence porosity through the creation or occupying interparticle pore space.

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Yang, Chenghao, Jiao Li, James Newkirk, Valerie Baish, Renzong Hu, Yu Chen, and Fanglin Chen. "Co-electrolysis of H2O and CO2in a solid oxide electrolysis cell with hierarchically structured porous electrodes." Journal of Materials Chemistry A 3, no. 31 (2015): 15913–19. http://dx.doi.org/10.1039/c5ta03264d.

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A solid oxide electrolysis cell with novel asymmetric-porous structured electrodes has been fabricated by freeze-drying tape-casting and impregnation methods. The straight channel-like pores in the porous electrode facilitate mass transport while the nano- or sub-micron-sized catalysts promote the electrode electrochemical reactions.

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Ge, Daohan, Jiwei Jiao, Xiaoqing Bao, Sheng Zhang, Ping Zhou, Yuelin Wang, and Songlin Feng. "Electrochemical Formation of Self-Positioned Nano-Sized Pores on Oxidized Porous Silicon Substrate." ECS Transactions 16, no. 3 (December 18, 2019): 201–7. http://dx.doi.org/10.1149/1.2982557.

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15

Zou, Yongshun, Huazhi Gu, Ao Huang, Lvping Fu, and Guangqiang Li. "Fabrication and analysis of lightweight magnesia based aggregates containing nano-sized intracrystalline pores." Materials & Design 186 (January 2020): 108326. http://dx.doi.org/10.1016/j.matdes.2019.108326.

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16

Jiang, Shu Wen, and Gui Ling Ning. "Densification of Alumina Ceramics by Infiltration of a Nano-Sized Alumina Sol into Alumina Green Samples." Materials Science Forum 675-677 (February 2011): 183–86. http://dx.doi.org/10.4028/www.scientific.net/msf.675-677.183.

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Infiltration of a nano-sized alumina sol into the green bodies is proposed to facilitate the ceramic sintering. The green samples were prepared by a colloidal processing based on drying induced forming, and then were immersed in a nano-sized alumina sol prior to their sintering at 1350-1600 oC. The alumina sol was characterized by using transmission electron microscopy and the grain structure of sintered alumina ceramics were examined by scanning electron microscopy. Significant densification of sintered samples was evidenced, in a depth of ~ 0.5 mm, on the samples treated with the alumina sol infiltration. It is indicated that filling of nano-sol into the micro-pores between particles of green samples enhanced the sintering densification process. The infiltration treatment by nano-sol may also provide an effective way to produce structurally gradient ceramics with a gradual changing density and/or composition from the surface into bulk.

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Chang, Dong Sook, Yong Jae Kwon, Chang Sung Lim, Jong Won Yoon, and Kwang Bo Shim. "Fabrication of Uniformly Nano-Sized Macroporous Silica Structure Using Templates." Key Engineering Materials 317-318 (August 2006): 729–32. http://dx.doi.org/10.4028/www.scientific.net/kem.317-318.729.

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Uniformly nano-sized macroporous silica consisting of well-defined pore sizes were successfully fabricated. A modified sol-gel process, using mono-dispersed polystyrene(PS) spheres as templates, was employed for configuring three-dimensionally ordered macroporous structure. The nano-sized macroporous silica structure was formed when the templates were removed by the calcination at high temperature. The pH value affected uniformly stacked order in the PS/silica matrix due to the PS being uniformly coated by silica film at appropriate pH value. Also this pH value affected the iso-electrics points between the PS and silica particles surface charges. The heating temperatures and the reaction times were considered to conform the microstructural morphology, the thermal deposition of organic components, the matrix wall thickness and densification behavior. Three-dimensionally assembled porous silica consists of uniform-sized pores of 200nm and high specific surface area of 163 m2/g.

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Lee, Soo Wohn, Huang Chen, Yi Zeng, and Chuan Xian Ding. "New Challenge of Plasma Spray Coatings in Nano Oxide Ceramics." Key Engineering Materials 317-318 (August 2006): 533–38. http://dx.doi.org/10.4028/www.scientific.net/kem.317-318.533.

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Nanostructured and conventional Al2O3, ZrO2, and TiO2 were deposited using an atmospheric plasma spraying (APS). The size of commercial nano-ceramic powders was varied from 5nm up to 150nm. The microstructure and phase composition of the plasma sprayed coatings on metallic substrate were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It was found that nano-sized ceramic powders enhanced the deposition efficiency on the metallic substrate rather than the micro-sized conventional commercial powders. Density and mechanical property such as microhardness were better in the case of the nano-sized ceramic powders than that of the conventional micro-sized ceramic powders, which are associated with the fine surface roughness and less size in pores of the coating layers. The wear rate of the nanostructured coating was lower than that of the conventional coating. The results were explained in terms of their microstructure of the coatings layers. Also, photocatalytic characterization of the plasma sprayed coatings, using nanocrystalline size TiO2 as feedstock with various powder sizes and shapes as well as adding with different photocatalytic oxides, was performed. The photocatalytic reactivity using plasma sprayed coating layers can be utilized into various applications.

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Oh, Bok-Hyun, Choong-Hwan Jung, Heon Kong, and Sang-Jin Lee. "Thermal Characteristics of Cu Matrix-SiC Filler Composite Using Nano-Sized Cu Powder." Journal of Nanoscience and Nanotechnology 21, no. 9 (September 1, 2021): 4964–67. http://dx.doi.org/10.1166/jnn.2021.19262.

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A Cu metal-ceramic filter composite with high thermal conductivity and a suitable thermal expansion coefficient was designed to be applied to high performance heat dissipation materials. The purpose of using the ceramic filler was to decrease the high coefficient of thermal expansion of Cu matrix utilizing the high thermal conductivity of Cu. In this study, a SiC ceramic filler powder was added to the Cu sol including Zn as a liquid phase sintering agent. The final complex was produced by applying a PVB polymer to prepare a homogeneous precursor followed by sintering in a reducing atmosphere. The pressureless sintered composite showed lower thermal conductivity than pure bulk Cu due to the some residual pores. In the case of the Cu–SiC composite in which 10 wt% of SiC filler was added, it showed a thermal conductivity of 100 W/m·°C and a thermal expansion coefficient of 13.3×10−6/°C. The thermal conductivity showed some difference from the theoretical calculated value due to the pores in the composite, but the thermal expansion coefficient did not show a significant difference.

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Qiao, Bin, Zi Long Tang, Zhong Tai Zhang, and Rui Long Zong. "The Application of Porous Anodic Aluminum Oxide Membrane in Luminescence." Key Engineering Materials 280-283 (February 2007): 505–8. http://dx.doi.org/10.4028/www.scientific.net/kem.280-283.505.

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In this article, the anodic aluminum oxide (AAO) was prepared by two-step anodizing process in oxalic acid electrolyte. And a blue-emission of AAO itself attributed to the oxalate was observed. The AAO membrane with ordered nano-sized porous structure was an important membrane to produce nano-materials. And luminescent nano-particles embedded in AAO, such as ZnO in this article, possessed notably special performances which were due to the quantum size effect and the special environment provided by the nano-pores. Since AAO membranes possessed a unique structure, in this paper, an assumption about the application of the membrane in field emission display (FED) and electroluminescence (EL) was proposed.

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Leela-adisorn, Uraiwan, Takuya Matsunaga, Seong Min Choi, Sawao Honda, and Hideo Awaji. "Alumina-Based Nanocomposites Fabricated by a Novel Soaking Method." Key Engineering Materials 317-318 (August 2006): 607–10. http://dx.doi.org/10.4028/www.scientific.net/kem.317-318.607.

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Nickel dispersed alumina matrix nanocomposites were fabricated using a novel soaking method. Secondary particles were introduced into the nano-pores of a porous matrix grains by a soaking method, such that γ-alumina powder was soaked in nickel nitrate solution under vacuum. During pre-calcination, nickel oxide particles were created inside of the nano-pores of γ-alumina. The alumina powders were then reduced under hydrogen atmosphere to obtain nano-sized metallic nickel embedded in γ-alumina grains. The alumina-nickel composite powders were sintered by pulse electric current sintering (PECS) technique with α-alumina seeds. The maximum strength of the alumina-nickel nanocomposites was 984 MPa after sintering at 1,450 °C with α-alumina seeds, where the specimen size was 2210 mm3. The maximum fracture toughness was 5.5 MPa·m1/2 after sintering at 1,350 °C with seeds measured by the single edge V-notched beam (SEVNB) method.

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Jiu, Bo, Wenhui Huang, Mingqian He, Chenhang Lv, and Fei Liang. "Quantitative Analysis of Micron-Scale and Nano-Scale Pore Throat Characteristics of Tight Sandstone Using Matlab." Applied Sciences 8, no. 8 (August 1, 2018): 1272. http://dx.doi.org/10.3390/app8081272.

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Based on micro-scale casting thin sections, nano-scale SEM images, and the pore distribution map identified through a binary image in Matlab, the pore size distribution and pore throat coordination number of the strata of Upper Paleozoic He8 section tight sandstone in the southeastern Ordos Basin were quantitatively analyzed with the above experimental data. In combination with a high-pressure mercury injection experiment, the pore throat distribution, the pore throat ratio, and the relationships between the characteristics, parameters, and pore permeability were investigated clearly. The results show that the tight sandstone pore space in the study area is dominated by micron-sized intergranular pores, dissolved pores, and intragranular pores. The nano-scale pore throat consisted of clay minerals, intercrystalline pores, and the flake intergranular pores of overgrowth quartz grains. Kaolinite and illite intercrystalline pores occupy the pore space below 600 nm, while the ones above 800 nm are mainly dominated by the intergranular pores of overgrowth quartz grains, and the 600–800 nm ones are transitional zones. The permeability of tight sandstone increases with the average pore throat radius, sorting coefficient, median pore throat radius, and average pore throat number. The porosity is positively correlated with the average pore radius and the average pore throat coordination number, and negatively correlated with the median pore throat radius.

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Xiao, Ling, Hongwei Fan, Wenjie Cheng, Zigang Li, and Ming Li. "Magnetic and mechanical properties of Fe-based α-Fe2O3/nano-sized MgO-coated composites." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 233, no. 6 (July 11, 2017): 1134–44. http://dx.doi.org/10.1177/1464420717720820.

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Fe-based α-Fe2O3/nano-sized MgO-coated soft magnetic composites were fabricated by powder metallurgy with 800 MPa pressure at room temperature, and then annealed at 400 ℃. A layer of iron oxide α-Fe2O3 was generated on the iron surface by passivation treatment. The processed iron powders were coated with nano-sized MgO by mixing method. The soft magnetic composites with sandwich structure (Fe + iron oxide + nano-sized MgO) resulted in an increased permeability at a higher frequency, and higher eddy current loss compared to that of the resin layer by the two-step annealing method, which indicates that the sandwich structure for the soft magnetic composites exhibited noticeably higher frequency stability. The relationship between compressed load and displacement for two kinds of soft magnetic composites implied that the density and stress release for iron play a leading role in the mechanical properties. The stress field analysis of the internal microstructure by finite element method shows that the cracks and pores are two important factors that affect the mechanical strength for the whole material.

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WANG, NING, WEIXUN ZHAO, PING WANG, and ZHENG WEI. "TO DEVELOP NANOSTRUCTURED THERMAL BARRIER COATINGS." International Journal of Modern Physics B 20, no. 25n27 (October 30, 2006): 4171–76. http://dx.doi.org/10.1142/s0217979206041045.

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Advanced turbine engines require the application of thermal barrier coatings (TBCs) to provide still higher reliability, thermal insulation effect and longer lifetime under harsh operating conditions. TBCs with nanostructure proved to be promising to deliver the desired property and performance. To exploit full potentials of the current widely used yttria-partially-stabilized zirconia (YSZ), nano-sized YSZ powders were developed and used as the ceramic source material. By controlling the deposition processes, novel TBCs with outstanding nanostructure such as nano-sized grains and pores were produced by atmospheric plasma spray (APS) and electron beam physical vapor deposition (EB-PVD), respectively. The incorporated nanostructure in TBCs resulted in substantial increase in thermal barrier effect and their lifetime. The long-term microstructure stability of the nanocoating was also investigated.

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Luo, Jun Ting, Chun Xiang Zhang, Hai Feng Ma, and Ge Wang. "Cold Isostatic Pressing–Normal Pressure Sintering Behavior of Amorphous Nano-Sized Silicon Nitride Powders." Advanced Materials Research 454 (January 2012): 17–20. http://dx.doi.org/10.4028/www.scientific.net/amr.454.17.

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The amorphous nano-sized silicon nitride powders were sintered by cold isostatic pressing –normal press sintering method. The sintering additives of Y2O3 and Al2O3 powders with average grain size less than 20nm were prepared by polyacrylamide gel method. Relative density of sintered materials rise and pore size reduce with increasing of cold isostatic pressing. When the pressure is 100MPa, the density is only 48% and average pores size is between 2μm and 20μm which obvious the first particle space. When the pressure is 200MPa, the density is 67% and agglomerated particle size reduce obviously as well as the pores size are between 0.1μm and 1.0μm which appears because of the second particle. Pressed compact with a relative density 74% and average pore size less than 0.5μm reach to a good density state at 300MPa pressure. Sintering material composites with Si2N2O and β-Si3N4 phases, compared with hot press sintering composites, which indicates that increasing of sintering press is conducive to the formation phase Si2N2O. Relative density is above 96% and average pore size is less than 500nm at sintering temperature 1800°C.

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Mito, Masaki, Tsuyoshi Tatano, Yuki Komorida, Takayuki Tajiri, Hiroyuki Deguchi, Seishi Takagi, Shigemi Kohiki, Masaaki Ohba, Ryotaro Matsuda, and Susumu Kitagawa. "Magnetic properties of nitric oxide molecules physisorbed into nano-sized pores of MCM-41." Microporous and Mesoporous Materials 132, no. 3 (August 2010): 464–69. http://dx.doi.org/10.1016/j.micromeso.2010.03.028.

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Gao, Peihu, Shengcong Zeng, Can Jin, Bo Zhang, Baiyang Chen, Zhong Yang, Yongchun Guo, et al. "Mechanical Properties of Multi-Sized Porous Thermal Barrier Coatings at Micro and Nano Scales after Long-Term Service at High Temperature." Coatings 12, no. 2 (January 28, 2022): 165. http://dx.doi.org/10.3390/coatings12020165.

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Atmospheric plasma-sprayed multi-sized porous structures in thermal barrier coatings (TBCs) were constructed with hollow spherical (HOSP) 8YSZ powders and polypropylene pore formers. The mechanical properties of the multi-sized TBCs were investigated through the nanoindentation method as comparations of the as-sprayed coating and those serving at 1100 °C for a long-term. The results showed that the introduction of the multi-sized pores into TBCs could lead to the decrease of the hardness and modulus as well as the increase of fracture toughness. The hardness and modulus of the coating increased, and the fracture toughness of the coating decreased with the prolongation of the serving times at high temperatures. The mechanical properties of the coating became stable after 60 days’ serving at 1100 °C. The hardness, elastic modulus and fracture toughness of the TBCs increased to 6.51, 7.79, 10.04 GPa and 126.36, 135.13, 145.22 GPa as well as 1.049, 1.157, 1.255 MPa·m0.5, respectively, corresponding to the multi-sized porous TBCs with 0%, 10% and 15% PP powders. The nano-size pores disappeared gradually in the multi-sized TBCs during serving at 1100 °C. The macropores deposited between the ceramic particles penetrated with little diffusion and were not easy to disappear. The introduction of a multi-scale pore structure into the TBCs could improve the stress-strain tolerance of the TBCs.

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Lee, Do Nam, Yeong Rim Kim, Sohyeon Yang, Ngoc Minh Tran, Bong Joo Park, Su Jung Lee, Youngmee Kim, Hyojong Yoo, Sung-Jin Kim, and Jae Ho Shin. "Controllable Nitric Oxide Storage and Release in Cu-BTC: Crystallographic Insights and Bioactivity." International Journal of Molecular Sciences 23, no. 16 (August 13, 2022): 9098. http://dx.doi.org/10.3390/ijms23169098.

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Crystalline metal–organic frameworks (MOFs) are extensively used in areas such as gas storage and small-molecule drug delivery. Although Cu-BTC (1, MOF-199, BTC: benzene-1,3,5-tricarboxylate) has versatile applications, its NO storage and release characteristics are not amenable to therapeutic usage. In this work, micro-sized Cu-BTC was prepared solvothermally and then processed by ball-milling to prepare nano-sized Cu-BTC (2). The NO storage and release properties of the micro- and nano-sized Cu-BTC MOFs were morphology dependent. Control of the hydration degree and morphology of the NO delivery vehicle improved the NO release characteristics significantly. In particular, the nano-sized NO-loaded Cu-BTC (NO⊂nano-Cu-BTC, 4) released NO at 1.81 µmol·mg−1 in 1.2 h in PBS, which meets the requirements for clinical usage. The solid-state structural formula of NO⊂Cu-BTC was successfully determined to be [CuC6H2O5]·(NO)0.167 through single-crystal X-ray diffraction, suggesting no structural changes in Cu-BTC upon the intercalation of 0.167 equivalents of NO within the pores of Cu-BTC after NO loading. The structure of Cu-BTC was also stably maintained after NO release. NO⊂Cu-BTC exhibited significant antibacterial activity against six bacterial strains, including Gram-negative and positive bacteria. NO⊂Cu-BTC could be utilized as a hybrid NO donor to explore the synergistic effects of the known antibacterial properties of Cu-BTC.

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Lee, Hyun Bom, Hiroyasu Tezuka, Equo Kobayashi, Tatsuo Sato, and Kee Do Woo. "Fabrication of (Al₂O₃-Al₃Nb)/Al Composite Materials by In-Situ Reaction Using MA Processed Al/Nb₂O₅ Powder." Materials Science Forum 654-656 (June 2010): 2931–34. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.2931.

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A planetary ball milling (PBM) technique was employed to fabricate mechanically alloyed (MA processed) Al-Nb2O5 composite powder. Nano or sub-micron sized Nb2O5 particles were homogeneously embedded in the Al particles after milling for various periods. None of cracks, by-products and pores were observed in the areas between embedded Nb2O5 particulates and Al matrix powder after milling. The sequence of the in-situ reaction was confirmed by DSC, XRD measurements, optical microscopy and EPMA. The specific temperature of the in-situ reaction was between 650 and 700°C. Al-based metal matrix composites (MMC) reinforced with the sub-sieve sized θ-Al2O3 particulates and Al3Nb intermetallic compound were successfully fabricated by the in-situ reaction process. The substituted Nb by the in-situ reaction was fully reacted with Al to form the Al3Nb intermetallic compound during sintering. A number of sub-sieve sized θ-Al2O3 particulates and Al3Nb intermetallic compound formed by the in-situ reaction between Al and Nb2O5 were homogeneously distributed in the Al matrix during sintering. Nano sized θ-Al2O3 particulates are preferentially distributed near the Al3Nb intermetallic compound and no by-products are formed in the interfaces with the Al matrix.

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Zou, Lijie, Mingyuan Ge, Jianming Bai, Chonghang Zhao, Hao Wang, Xianghui Xiao, Hui Zhong, et al. "3D Morphology of Bimodal Porous Copper with Nano-Sized and Micron-Sized Pores to Enhance Transport Properties for Functional Applications." ACS Applied Nano Materials 3, no. 8 (July 1, 2020): 7524–34. http://dx.doi.org/10.1021/acsanm.0c01163.

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Canepa, Paolo, Giuseppe Firpo, Elena Gatta, Roberto Spotorno, Paolo Giannoni, Rodolfo Quarto, Maurizio Canepa, and Ornella Cavalleri. "A Two-Step Approach to Tune the Micro and Nanoscale Morphology of Porous Niobium Oxide to Promote Osteointegration." Materials 15, no. 2 (January 8, 2022): 473. http://dx.doi.org/10.3390/ma15020473.

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We present a two-step surface modification process to tailor the micro and nano morphology of niobium oxide layers. Niobium was firstly anodized in spark regime in a Ca- and P-containing solution and subsequently treated by acid etching. The effects of anodizing time and applied potential on the surface morphology is investigated with SEM and AFM, complemented by XPS compositional analysis. Anodizing with a limiting potential of 250 V results in the fast growth of oxide layers with a homogeneous distribution of micro-sized pores. Cracks are, however, observed on 250 V grown layers. Limiting the anodizing potential to 200 V slows down the oxide growth, increasing the anodizing time needed to achieve a uniform pore coverage but produces fracture-free oxide layers. The surface nano morphology is further tuned by a subsequent acid etching process that leads to the formation of nano-sized pits on the anodically grown oxide surface. In vitro tests show that the etching-induced nanostructure effectively promotes cell adhesion and spreading onto the niobium oxide surface.

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Jeong, S. H., S. O. Jang, Kyoung Nam Kim, H. K. Kwon, Yong Duk Park, and B. I. Kim. "Remineralization Potential of New Toothpaste Containing Nano-Hydroxyapatite." Key Engineering Materials 309-311 (May 2006): 537–40. http://dx.doi.org/10.4028/www.scientific.net/kem.309-311.537.

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Hydroxyapatite is the main component of enamel that gives the tooth a bright white appearance and eliminates the diffused reflection of light by filling up the fine pores of the tooth surface. Accordingly, remineralization of the teeth can be expected to some extent if hydroxyapatite is used to treat an incipient caries lesion (early white spot lesion). In addition, the remineralization effect will be increased if the particle size of hydroxyapatite can be reduced to less than that of the micron-size in existing toothpaste preparations. The aim of this in vitro study was to evaluate the effect of nano-hydroxyapatite toothpaste, which was produced by nano-technology, on the remineralization of human enamel. A tooth specimen, on which artificial incipient caries had been induced, was immersed into two toothpaste slurries for remineralization. One contains nano-sized hydroxyapatite and fluoride, and the other contains nano-sized hydroxyapatite excluding fluoride. In order to evaluate the remineralization effect, the Vickers Hardness Number & SEM image of the enamel surface was evaluated at each step. There were significant differences in VHN values between those obtained before and after the remineralization steps. The results showed that the remineralization effect increased with increasing immersing time (P<0.05). However, there were no significant differences in VHN values between the two groups (P>0.05). SEM also demonstrated differences the in micro surface at each step. In conclusion, a toothpaste containing nano-sized hydroxyapatite has the potential to remineralize an incipient caries lesion. In addition, the addition of fluoride had no synergistic effect on remineralization.

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Miki, Takeshi, Kaori Nishizawa, Kazuyuki Suzuki, and Kazumi Kato. "Electrochemical Properties of Nanoporous TiO₂ Films." Key Engineering Materials 301 (January 2006): 83–86. http://dx.doi.org/10.4028/www.scientific.net/kem.301.83.

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The precursor solutions containing TiO2 sol for nanoporous films were prepared by hydrolyzing titanium(IV) isopropoxide and adding trehalose dihydrate. The porous and thick TiO2 film was prepared by dip-coating technique on glass substrate and heating at 500 °C. The film was composed of nano sized particles (10-20 nm) and pores (7 nm). The specific surface area of the film was 163 m2/g. The film had humidity-sensitive electrical resistance at room temperature.

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Zhou, Jian Er, Qi Bing Chang, Ying Chao Dong, Xue Bing Hu, Yong Qing Wang, and Stuart Hanpshire. "Water Permeates in Ceramic Membrane Modified with Nano Inorganic Coating." Advanced Materials Research 239-242 (May 2011): 27–30. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.27.

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Membrane surface modification is the important method to decrease membrane fouling. The hydrophilic modification of ceramic membrane with nano-sized inorganic coating is prepared by the wet chemical methods. The thin nano coating is not a separating top layer but distributes uniformly on the surface of the membrane pore wall. The coating does not change the structure of the membrane pores. Therefore, water flows on not the pore wall but the nano coating surface. The results show that the water flux of the modified membrane is higher than that of the unmodified membrane despite that the mean pore size of the modified membrane decreases. The “boundary slip” is used to explain this special phenomenon. What generates the slippage? The slippage is relative with the molecular layer adhered tightly on the hydrophilic pore wall, the roughness and the surface charge of the nano coating, the interaction between the ions in water and the nano coating, et al.

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UENO, Yuko, and Katsuhiro AJITO. "Terahertz Time-domain Spectra of Aromatic Carboxylic Acids Incorporated in Nano-sized Pores of Mesoporous Silicate." Analytical Sciences 23, no. 7 (2007): 803–7. http://dx.doi.org/10.2116/analsci.23.803.

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Zhou, Qilai, Lihong Xue, Ya Wang, Heping Li, Takumi Chikada, Yasuhisa Oya, and Youwei Yan. "Preparation of Li 2 TiO 3 ceramic with nano-sized pores by ultrasonic-assisted solution combustion." Journal of the European Ceramic Society 37, no. 11 (September 2017): 3595–602. http://dx.doi.org/10.1016/j.jeurceramsoc.2017.04.027.

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37

Ueno, Yuko, Tsutomu Horiuchi, Osamu Niwa, Hao-Shen Zhou, Takeo Yamada, and Itaru Honma. "Portable automatic BTX measurement system with microfluidic device using mesoporous silicate adsorbent with nano-sized pores." Sensors and Actuators B: Chemical 95, no. 1-3 (October 2003): 282–86. http://dx.doi.org/10.1016/s0925-4005(03)00540-9.

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38

Kim, Y., Soo Ryong Kim, B. G. Song, Vikram V. Dabhade, B. K. Sea, and Woo Teck Kwon. "Nanoporous SiC Membrane Derived from Preceramic Polymer." Solid State Phenomena 124-126 (June 2007): 1733–36. http://dx.doi.org/10.4028/www.scientific.net/ssp.124-126.1733.

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Ceramic membranes having nano sized pores have great potential for gas separation at high temperature due to their good thermal stability. Moreover, nanoporous silicon carbide membrane has potential application under hydrothermal condition at high temperature. In this research, nanoporous SiC membrane has been developed on the porous alumina plate using preceramic polymers as CVD precursor at 850oC. The preceramic polymer was characterized with Si29 NMR, FT-IR, GC and TGA. The prepared SiC membrane was characterized with SEM and EDS. The hydrogen permeability and selectivity toward nitrogen gas were measured using a GC.

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Liu, Xiong, Weiping Cai, and Huijuan Bi. "Optical Absorption of Copper Nanoparticles Dispersed within Pores of Monolithic Mesoporous Silica." Journal of Materials Research 17, no. 5 (May 2002): 1125–28. http://dx.doi.org/10.1557/jmr.2002.0166.

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Nano-sized copper particles are loaded into the pores of monolithic mesoporous silica by soaking and drying, followed by thermal reduction of copper nitrate [Cu(NO3)2]in a hydrogen atmosphere at 973 K for 90 min. It has been shown that copper nanoparticles are isolated from each other and highly uniformly dispersed inside the pores of silica. It is found that the surface plasmon resonance peak of the copper particles shows a significant red-shift with decreasing the particle size, which is in contrast to the corresponding fully embedded system. The peak decreases with exposure time to air and exhibits a linear relation with logarithmic exposure time. This red-shift phenomenon and decrease are explained on the basis of the structural features of this new composite or coexistence of local porosity and the nanoparticle's free surface in contact with air.

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Liu, Yajing, Weiyao Zhu, Bingbing Li, and Lianzhi Yang. "Simulation study on the flow behaviors of weak electrolyte solutions in nano-sized and micron-sized pores considering electric double layer interactions." Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 44, no. 2 (April 27, 2022): 3532–43. http://dx.doi.org/10.1080/15567036.2022.2067266.

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Hong, Seong Ho, Younghyun Cho, and Sang Wook Kang. "Formation of Water-Channel by Propylene Glycol into Polymer for Porous Materials." Membranes 11, no. 11 (November 16, 2021): 881. http://dx.doi.org/10.3390/membranes11110881.

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In this study, a porous membrane with a cellulose acetate (CA) matrix was fabricated using propylene glycol with a water pressure treatment without a metal salt as an additive. The water pressure treatment of the fabricated CA membrane with propylene glycol yielded nanopores. The nanopores were formed as the additives in the CA chains led to plasticization. The weakened chains of the parts where the plasticization occurred were broken by the water pressure, which generated the pores. Compared to the previous study with glycerin as an additive, the size of the hydration region was controlled by the number of hydrophilic functional groups. When water pressure was applied to the CA membrane containing propylene glycol as an additive, the hydration area was small, so it was effective to control the pore size and the number of nano pores than glycerin. In addition, the number of nanopores and pore size could be easily adjusted by the water pressure. The porosity of the membrane was increased owing to the trace amount of propylene glycol, confirmed by scanning electron microscopy (SEM) and porosimetry. The interaction between the CA and propylene glycol was verified by Fourier-transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). Consequently, it was the optimum composition to generate pores at the CA/propylene glycol 1:0.2 ratio, and porosity of 69.7% and average pore diameter of 300 nm was confirmed. Since it is a membrane with high porosity and nano sized pores, it is expected to be applied in various fields.

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Dogahe, Kiarash Jamali, Vinzenz Guski, Marijo Mlikota, Siegfried Schmauder, Walter Holweger, Joshua Spille, Joachim Mayer, Alexander Schwedt, Bernd Görlach, and Jürgen Wranik. "Simulation of the Fatigue Crack Initiation in SAE 52100 Martensitic Hardened Bearing Steel during Rolling Contact." Lubricants 10, no. 4 (April 7, 2022): 62. http://dx.doi.org/10.3390/lubricants10040062.

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An investigation on the White Etching Crack (WEC) phenomenon as a severe damage mode in bearing applications led to the observation that in a latent pre-damage state period, visible alterations appear on the surface of the raceway. A detailed inspection of the microstructure underneath the alterations reveals the existence of plenty of nano-sized pores in a depth range of 80 µm to 200 µm. The depth of the maximum Hertzian stress is calculated to be at 127 µm subsurface. The present study investigates the effect of these nanopores on the fatigue crack initiation in SAE 52100 martensitic hardened bearing steel. In this sense, two micro-models by means of the Finite Element Method (FEM) are developed for both a sample with and a sample without pores. The number of cycles required for the crack initiation for both samples is calculated, using the physical-based Tanaka–Mura model. It is shown that pores reduce the number of cycles in bearing application to come to an earlier transition from microstructural short cracks (MSC) to long crack (LC) propagation significantly.

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43

Jung, Mi, Ji-Hoon Kim, and Young-Wan Choi. "Preparation of Anodic Aluminum Oxide Masks with Size-Controlled Pores for 2D Plasmonic Nanodot Arrays." Journal of Nanomaterials 2018 (August 26, 2018): 1–9. http://dx.doi.org/10.1155/2018/6249890.

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Anodic aluminum oxide (AAO) layers with nano-sized pores have been used as shadow masks for the fabrication of two-dimensional (2D) metal nanodot arrays (NDAs). However, the localized surface plasmon resonance (LSPR) of size-controlled NDAs fabricated using AAO masks has not been much studied. In this study, we report on the improved preparation method and utilization of an ultrathin AAO mask for the fabrication of 2D plasmonic metal NDAs. The greatest challenge in preparing an AAO mask is to control the pore diameter and to make it reproducible. AAO masks with size-controlled pores were reproducibly prepared using a two-step chemical wet etching method. Ag NDAs with different dot diameters (42, 60, and 80 nm) and Ag, Cu, and Au NDAs with dot a diameter of 80 ± 5 nm were fabricated on indium tin oxide glass substrates using AAO masks. The wavelengths corresponding to LSPR of 2D metal NDAs were investigated using ultraviolet–visible spectroscopy. Our results show that AAO masks with tunable pores can be used as shadow masks for the fabrication of 2D plasmonic NDAs.

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44

Wu, Sheng, Yongchun Tang, Mian Lin, and Andrew Sneddon. "Headspace Isotope & Compositional Analysis for Unconventional Resources: Gas in Place, Permeability and Porosity Prediction and Completions Planning." Geosciences 10, no. 9 (September 17, 2020): 370. http://dx.doi.org/10.3390/geosciences10090370.

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Cuttings/cores’ Headspace Isotope and Composition Analysis (HICA) provides an effective way to calculate the nano pore throat size and distributions much like nitrogen and CO2 adsorption BET/BJH analysis, and it could also provide information about the original pore pressure or gas in place. Tight gas and oil storage is different from conventional where a majority of oil and gas are stored in nanometer sized pores (nanopores). Therefore the nanofludics, i.e., nanometer scale capillary sealing and opening in nanopores of tight rocks, plays a key role in overpressure conservation and storage of oil and gas, and also the fracing process involves the opening of the nano pore capillary seals through rock-fluid interactions. The rock-fluid nanofluidics interactions during fracing could also be studied through HICA and the results could help the optimization of fracing designs.

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45

Kang, Jung-In, Han-Cheol Choe, and Mee-Kyoung Son. "Nano/Micro-Sized Morphologies of Hydroxyapatite Coatings Containing Mn and Si on an Oxidized Ti–6Al–4V Alloy Surface for Dental Implants." Journal of Nanoscience and Nanotechnology 21, no. 7 (July 1, 2021): 3701–6. http://dx.doi.org/10.1166/jnn.2021.19169.

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To improve the surface characteristics of Ti–6Al–4V dental implants and the binding between the bone and implant surface, biocompatible oxide films were formed by plasma electrolytic oxidation (PEO). The PEO treatment was performed using electrolyte solutions containing Ca (calcium acetate monohydrate), P(calcium glycerophosphate), Mn (manganese(II) acetate tetrahydrate), and Si (sodium metasilicate nonahydrate), which are the major constituents of bone, for 3 min at 280 V. The morphology and crystalline phase of the PEO-treated surfaces were characterized using field-emission scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction, and Fourier transform infrared spectroscopy. All the obtained PEO-treated samples exhibited a morphology comprising porous structures. Oval and irregular pore structures were observed as the Mn content increased. As the Si content increased, the areas occupied by the pores increased. When both, Si and Mn were used for the PEO treatment, the number of nano- to micro-sized pores gradually decreased with the increasing ratios of the constituents.

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46

Sun, Xiao Lin, Ai Min Li, Wei Fang Dong, Kang Ning Sun, Ming Du, and Wei Li Wang. "Influence of Different Processing Parameters on the Structure of Anodic Aluminum Oxide Membrane." Advanced Materials Research 306-307 (August 2011): 1304–10. http://dx.doi.org/10.4028/www.scientific.net/amr.306-307.1304.

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Oxide membranes are one kind of porous materials with many nano-sized pores. In our work, the two-step anodization method was used to fabricate Anodic aluminum oxide (AAO) membranes. The surface, cross-section micrographs and chemical composition were analyzed by field emission scanning electron microscopy (FESEM). From the FESEM micrographs, it can be easily seen that the self-ordered hexagonal pore channels were parallel and perpendicular to the surface of membrane when AAO membrane was prepared in oxalic acid at 0.2mol/L for 4h. In addition, the biggest pore diameter was 78nm, and the thickness ranged from a few microns to tens of microns in the suitable preparation parameters.

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Cheng, G. S., L. D. Zhang, S. H. Chen, Y. Li, L. Li, X. G. Zhu, Y. Zhu, G. T. Fei, and Y. Q. Mao. "Ordered nanostructure of single-crystalline GaN nanowires in a honeycomb structure of anodic alumina." Journal of Materials Research 15, no. 2 (February 2000): 347–50. http://dx.doi.org/10.1557/jmr.2000.0054.

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Ordered nanostructure of single-crystalline GaN nanowires in a honeycomb structure of anodic alumina was synthesized through a gas reaction of Ga2O vapor with a constant ammonia atmosphere at 1273 K in the presence of nano-sized metallic indium catalysis. Atomic force microscopy, x-ray diffraction, Raman backscattering spectroscopy, scanning electron microscopy, and transmission electron microscopy indicate that the ordered nanostructure consists of single-crystalline hexagonal wurtzite GaN nanowires in the uniform pores of anodic alumina about 20 nm in diameter and 40–50 μm in length. The growth mechanism of the ordered nanostructure is discussed. The photoluminescence spectrum of this nanostructure is also reported.

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Bouchet-Spinelli, Descamps, Liu, Ismail, Pham, Chatelain, Leïchlé, et al. "Polarization Induced Electro-Functionalization of Pore Walls: A Contactless Technology." Biosensors 9, no. 4 (October 11, 2019): 121. http://dx.doi.org/10.3390/bios9040121.

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This review summarizes recent advances in micro- and nanopore technologies with a focus on the functionalization of pores using a promising method named contactless electro-functionalization (CLEF). CLEF enables the localized grafting of electroactive entities onto the inner wall of a micro- or nano-sized pore in a solid-state silicon/silicon oxide membrane. A voltage or electrical current applied across the pore induces the surface functionalization by electroactive entities exclusively on the inside pore wall, which is a significant improvement over existing methods. CLEF’s mechanism is based on the polarization of a sandwich-like silicon/silicon oxide membrane, creating electronic pathways between the core silicon and the electrolyte. Correlation between numerical simulations and experiments have validated this hypothesis. CLEF-induced micro- and nanopores functionalized with antibodies or oligonucleotides were successfully used for the detection and identification of cells and are promising sensitive biosensors. This technology could soon be successfully applied to planar configurations of pores, such as restrictions in microfluidic channels.

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Ogawa, Shigeo. "1/λ^4 scattering of light during the drying process in porous Vycor glass with nano-sized pores." Journal of the Optical Society of America A 30, no. 2 (January 7, 2013): 154. http://dx.doi.org/10.1364/josaa.30.000154.

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Noguchi, Hiroki, Marzia Sultana, Nanami Hano, Yutaka Kuwahara, Makoto Takafuji, Shoji Nagaoka, Hongdeng Qiu, and Hirotaka Ihara. "Fabrication of Carbon-Like, π-Conjugated Organic Layer on a Nano-Porous Silica Surface." Nanomaterials 10, no. 9 (September 20, 2020): 1882. http://dx.doi.org/10.3390/nano10091882.

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This paper presents a new type of black organic material-porous silica composite providing an extremely highly selective adsorption surface. This black composite was prepared by lamination on nano-sized pores with a carbon-like, π-extended structure, which can be converted via the on-site polymerization of 1,5-dihydroxynaphthalene with a triazinane derivative and a thermally induced condensation reaction with denitrification. This bottom-up fabrication method on porous materials had the great advantage of maintaining the pore characteristics of a raw porous material, but also the resultant black surface exhibited an extremely high molecular-shape selectivity; for example, that for trans- and cis-stilbenes reached 14.0 with the black layer-laminated porous silica, whereas it was below 1.2 with simple hydrophobized silica.

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Journal articles on the topic 'Nano-sized pores'

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