Ex 250

For characterization of surface morphology and CNT structures, atomic force microscopy (AFM Park Systems X-70 city, Suwon, Korea) in tapping mode operation and scanning electron microscope (SEM, Coxem CX-100, Daejeon, Korea) were used. To directly confirm the CNT structure and chemical elements of catalysts, a transmission electron microscopy (TEM, JEM2100F, Tokyo, Japan) and energy dispersive spectroscopy (EDS, Horiba EX250, Tokyo, Japan) were used. As for TEM sample preparation, as-grown CNTs were dispersed in ethanol using ultrasonication, then, the solution was dropped into a TEM grid and allowed it to dry. Raman spectroscopy (Horiba Aramis, Piscataway, NJ, USA), a versatile and convenient tool for estimating the structural completeness of CNTs by comparing the peak intensities of a structural-disorder-induced peak (D-band, I_D) around 1350 cm⁻¹ and tangential stretching vibration mode of graphite (G-band, I_G) around 1590 cm⁻¹, was also employed [16 (link)]. For the Raman analysis, the excitation wavelength of laser was 532 nm and spot size was 1 μm. An X-ray diffractometer (PANalytical X’Pert Pro, Eindhoven, The Netherlands) was employed to address the evolution of constituent of surface layers from as-received to after CNT growth. The analysis was performed with a radiation of Cu-Kα (λ = 1.5418 Å) with a step size of 0.1° and scan speed of 0.005 °/s at room temperature.

The SEM machine was equipped using an energy-dispersive X-ray spectrometer (EDS; EX-250, HORIBA, Kyoto, Japan). The s quantitative analysis of the surface elements on the particles before and after the addition of Mg was conducted by measuring the ratios of the emission X-ray lines that were obtained from the elements Mg, Ca, and P.

Ti disc surfaces were analyzed by energy-dispersive spectrometry (EX-250; HORIBA, Kyoto, Japan) with an electron beam covering a 70-µm spectrum and an accelerating voltage of 15 kV to derive the surface elemental composition of the surfaces of control and Er,Cr:YSGG laser–treated discs.

Selenium nanoparticles (SeNPs) using chitosan as a stabilizer were synthesized using a controllable reduction method, as described in Xia et al. [5 (link)]. Freshly prepared ascorbic acid solution (100 mM) was added into aqueous 0.25% (w/v) chitosan solution and mixed by magnetic stirring. Drop by drop sodium selenite solution (25 mM) was added into the mixture in the dark. The mixture was then made up to 25 mL by MilliQ water (Millipore, Burlington, MA, USA) and allowed to react at room temperature for 12 h in the dark before subjected to extensive dialysis (Mw cut off: 8000).
Size distribution of the nanoparticle was measured by high-resolution transmission electron microscopy (HRTEM; JEOL 2010, Horiba EX-250, Peabody, MA, USA) and NanoSight NS300 (Malvern Instruments Ltd., Worcestershire, UK). The elemental compositions of the SeNPs were measured by energy dispersive X-ray spectroscopy (EDX) under TEM. HRTEM and selected area electron diffraction (SAEN) pattern of the SeNPs were acquired on a JEOL 2010 microspore to understand the crystal structure of the NP. The Se concentration in the SeNP stock was determined by ICP-MS (Agilent 7500, Santa Clara, CA, USA).

A field-emission scanning electron microscope (FE-SEM, VEGA 3, TESCAN, Brno-Kohoutovice, Czech) was utilized to observe the morphology of superhydrophobic surface. Element constitution and element valence were measured by energy-dispersive X-ray spectroscopy (EDS, EX-250, Horiba Ltd, Kyoto, Japan) and X-ray diffraction (XRD, D/MAX-2000, Rigaku, Tokyo, Japan) patterns. Contact angles (CAs) of 5 μL water droplets on the superhydrophobic carbon steel sheet under the same treatment process were tested by an optical contact-angle meter system (JC2000D, POWEREACH, Shanghai, China). The drag reduction effect was valued by the static driving angle (the angle of stator magnetic potential behind rotor magnetic potential) to rotors with and without superhydrophobic surfaces under the same driving condition, the sine of which is proportional to the friction torque.

The contact of bone-substituting biomaterials with the biological environment is directly related to the success of the osteointegration process. Among them, in vitro tests using simplified model fluids such as Hanks’ Balanced Salt Solution (HBSS) can be practiced as a first step to evaluate the effects of implantable materials in vivo [25 (link)]. The composition of HBSS contained many inorganic ions, such as Ca²⁺ and HPO₄²⁻, which was assumed to form complexes with TA. Briefly, the TA-supplemented hydrogels were immersed in 2 mL of Hank’s balanced salt solution (1x HBSS, Gibco, Cat No. 14025076) and subject to continuous stirring at 37 °C for 4 weeks [26 (link)]. HBSS was replenished every two days and samples were removed at various intervals, rinsed with DI water and dried in an oven at 50 °C, then stored for subsequent analysis. Hydrogel mineralization was observed using a scanning electron microscope (SEM, HITACHI S-3000N, Tokyo, Japan). Elemental analysis was also performed using an SEM equipped with an energy dispersive X-ray spectrometer (EDX, HORIBA EX-250, Tokyo, Japan).