S 4800

All specimens were collected around Oshima Island (31°31.35'N, 131°24.27'E) (Fig. 1), Miyazaki, Japan, by SCUBA diving and snorkeling. A small piece of tissue (5–10 mm) from each specimen was used for molecular analyses and the remainder was preserved in 99% ethanol for morphological analyses as reported by Koido et al. (2019) (link).
Specimens were previously deposited in Miyazaki University, Fisheries Sciences (MUFS) but were subsequently transferred and deposited at the Kuroshio Biological Research Foundation, Kochi, Japan (KBF) in the octocoral collection (OA). Morphological characteristics examined under a stereomicroscope included colony height, length and width of the stalk, presence of branches, length and width of polyps, length and width of tentacles, length and width of pinnules, number of rows of pinnules, and number of pinnules in the aboral row. Sclerites from polyps, and ones from the surface and interior of both stalk and branches of each specimen were examined. Sclerite shape, size, and microstructure were examined with light microscopy and scanning electron microscope (SEM) (HITACHI S-4800 and JEOL JSM-6500F).

The morphology and structure of the products were characterized using a SEM (S-4800) and a TEM (JEOL JEM-2100F) at accelerating voltages of 5 kV and 200 kV, respectively. The pore-size distribution of the products was determined by dynamic light scattering (DLS) using a Malvern Zeta Seizer instrument. N₂ adsorption-desorption isotherms were measured using a Micromeritics ASAP 2020 M porosity analyzer. The samples were outgassed at 573 K for at least 2 h in a vacuum. The Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods were used to determine pore volume, pore size and the surface areas of the samples.

The sintering shrinkage curves were derived from the curves of the pressure head displacement vs time/temperature from 1000 °C upwards, where the thermal expansion of graphite dies and samples were taken into consideration³¹ .
The Archimedes’ principle density measurements were employed to determine the relative densities of all samples. The phase composition of all samples was determined using XRD (Bruker D8 Advance) with Cu-Kα radiation with a step size of 0.02° 2θ over a scanning range of 15–85° 2θ. Microstructural characterization was performed using FESEM (Hitachi S-4800) and HRTEM (JEOL 200CX) at an accelerating voltage of 200 kV.
FTIR spectra were recorded on a Bruker TENSOR27 spectrometer with sample material embedded in KBr disks. Grind the samples thoroughly with an agate mortar. Transfer weighed amounts of sample powder (particle size <10 μm) approximate 1 mg, and KBr (GR) dry powder approximate 200 mg. The two powders were mixed evenly and ground thoroughly while baked with an infrared heat lamp. Transfer the ground mixture into a mold with 10 mm inner diameter and pressurize to 10 MPa, then remove the pressed translucent disk. The spectrometer runs the background channel without a sample, then puts the disk and runs the sample channel. The scanning range is 3000–400 cm⁻¹.

The morphology of Fe₃O₄/CNT and Fe₃O₄/CNT/Gent was observed using SEM (S4800, Japan) and TEM (JEOL JEM-2100F, Japan). Elemental mapping images were obtained using a TEM (JEOL JEM-2100F, Japan). The surface compositions, chemical structure, and crystal structures were collected with XPS (250Xi, United States), FTIR (Nicolet IS10, United States), and XRD (D8 Advanced, Germany) utilizing CuKα radiation. The magnetic properties of the prepared samples were using vibrating sample magnetometer (SK-300, Japan).

Fixed specimens were dehydrated through a graded series of ethanol dilutions, and dried within a Tousimis Samdri-790 Critical Point Dryer (Tousimis Research Corp., Rockville, MD) with CO₂ as an intermediate. Dried specimens were mounted on aluminum stubs, sputter coated with a gold-palladium alloy, and imaged with either a HITACHI S4800 or a JEOL JSM 6335 field emission scanning electron microscope.

As-synthesized products were characterized by D/Max-2550 PC X-ray diffractometer (XRD, Rigaku, Cu-Kα radiation), X-ray photoelectron spectroscopy (XPS, PHI5000VersaProbe), scanning electron microscopy (SEM, HITACHI, S-4800) and transmission electron microscopy (TEM, JEOL, JEM-2100F) equipped with an energy-dispersive X-ray spectrometer (EDX). The Co₃O₄@PPy samples were easily scraped off from the Ni foam substrate for the Fourier transform infrared (FTIR) test, and the FTIR spectrum was recorded on a Nicolet 6700 FTIR spectrometer (Bruker).