A nanoforest structure for practical surface-enhanced Raman scattering substrates

A nanoforest structure for surface-enhanced Raman scattering (SERS) active substrates is fabricated and analyzed. The detailed morphology of the resulting structure can be easily controlled by modifying the process parameters such as initial gold layer thickness and etching time. The applicability of the nanoforest substrate as a label-free SERS immunosensor is demonstrated using influenza A virus subtype H1N1. Selective binding of the H1N1 surface antigen and the anti-H1 antibody is directly detected by the SERS signal differences. Simple fabrication and high throughput with strong in-plane hot-spots imply that the nanoforest structure can be a practical sensing component of a chip-based SERS sensing system.     

Melt complex viscosity and molecular weights for homo-polypropylene modified by grafting bifunctional monomers under electron beam irradiation

High melt viscosity polypropylene was manufactured by grafting bifunctional monomers, HDDA (1,6-hexanediol diacrylate) and TPGDA (tripropyleneglycol diacrylate), onto homo-polypropylene under an electron beam irradiation. Melt complex viscosity (η^∗) of modified polypropylene was sensitive to irradiation dose and monomer content. The melt viscosity of the polypropylene modified with TPGDA increased to 132,290 Pa s (at 190 °C and 0.1 rad/s of frequency) from 5039 Pa s for virgin homo-polypropylene. TPGDA monomer could give higher melt viscosity at low dosages than HDDA monomer, probably due to the structural feature of TPGDA with three numbers of methyl groups.Modified polypropylene with high melt complex viscosity had a broad molecular weight distribution with remarkable shift to higher molecular weight leading to high values of both and . Melt viscosity of modified polypropylene could be properly correlated by the equation , where the term gave a dominant effect for the estimation of η^∗.     

Decomposition of 2-chlorophenol by supercritical water oxidation with zirconium corrosion

The 2-chlorophenol (2-CP) was oxidized in a continuous anti-corrosive supercritical water system. The variation of decomposition efficiency by the corrosion of zirconium 702 was also studied at the variation of feed concentration and reaction time. According to AES depth profile, the oxygen penetration depth to zirconium was not proportional to the exposure time. It might stem from the formation of zirconium oxide layer on the surface delaying the corrosion. However, the increase in feed concentration accelerated the corrosion of zirconium. The corrosion of zirconium at low feed concentration led to the improvement of decomposition efficiency due to the catalytic effect of formed zirconium oxides, while that at high feed concentration deteriorated the decomposition efficiency owing to large consumption of oxidant in corrosion.     

Development of a numerical analysis methodology for the multi-dimensional and multi-phase phenomena of a sodium–water reaction in an SFR steam generator

A numerical approach on the exothermic sodium–water reaction (SWR) in a SFR steam generator is carried out by using a commercial computational fluid dynamics (CFD) code. The applicability of the analysis models and the physical limitations of some codes was investigated to select the most powerful CFD code to simulate a chemically reacting flow with various phases and components. In order to model the phenomena, among the several chemical reaction models studied, the eddy dissipation model (EDM) was employed because the EDM is the proper one when the reaction rate is sufficiently high when compared to the flow transport time. Based on the basic understandings for the characteristics of the SWR phenomena and the capabilities of the CFD codes, the numerical analysis methodology for a SWR was developed and transient analyses up to 0.05 s and 0.1 s with a time step of 0.0001–0.0005 s were carried out with a consideration of the geometric effect. The vapor mass flow rate and the corresponding hydrogen production rate were also calculated and compared with the conventional one-dimensional analysis results. As a result, it was found that the multi-dimensional approach underestimates the hydrogen production rate by 17% when compared to the theoretical values, and the difference is mainly caused by a multi-dimensional effect of the chemical reaction. The analysis performed in this study presents detailed information on each phase and the components of the SWR process and it also reflects the realistic SWR phenomena well. In order to confirm the applicability of the methodology, a multi-dimensional analysis was also carried out for the 49 tube bundle condition, and it was found that the results of the analysis were satisfactory.     

Novel application of an optical inspection system to determine the freshness of Scomber japonicus (mackerel) stored at a low temperature

Food Science and Biotechnology - This study evaluated the use of an optical inspection system (OIS) to determine the freshness of mackerel (Scomber japonicus). The correlations between the light...     

Fabrication and scanning-angle temperature dependence of metal-based, optical resonant scanners with PZT actuation

Metal-based, optical scanning devices with a large mirror size of 1 mm(2) and a wide scanning angle of over 90 degrees were fabricated. A high optical scanning angle (90 degrees ) was achieved at a resonance frequency of 7.33 kHz and a driving voltage of 80 V (peak-to-peak) in ambient air without vacuum packaging. We compared the performance of metal-based, optical scanners driven by PZT bulk ceramic and aerosol-deposited PZT thick films over the temperature range from -20 degrees C to 80 degrees C in an environmental chamber.     

Pressure Effect on the Coexistence of Magnetism and Superconductivity in Ho1−x Dy x Ni2B2C

We have measured the transport properties of Ho_(1–x)Dy _x Ni₂B₂C (x=0.1, 0.4) single crystals to study the effects of high pressure conditions on the superconductivity and magnetism. The pressure affects the pair-breaking interaction by changing the magnetic exchange integral J _sf. In the case of x=0.1, the superconducting transition temperature T _c is higher than the Néel temperature T _N and decreases as the pressure increases. On the other hand, for x=0.4, when have lower T _N than T _c, T _c does not change with increasing pressure. These results are due to the effect of the pressure on J _sf.     

A Hybrid Attention-Based Residual Unet for Semantic Segmentation of Brain Tumor

Segmenting brain tumors in Magnetic Resonance Imaging (MRI) volumes is challenging due to their diffuse and irregular shapes. Recently, 2D and 3D deep neural networks have become famous for medical image segmentation because of the availability of labelled datasets. However, 3D networks can be computationally expensive and require significant training resources. This research proposes a 3D deep learning model for brain tumor segmentation that uses lightweight feature extraction modules to improve performance without compromising contextual information or accuracy. The proposed model, called Hybrid Attention-Based Residual Unet (HA-RUnet), is based on the Unet architecture and utilizes residual blocks to extract low- and high-level features from MRI volumes. Attention and Squeeze-Excitation (SE) modules are also integrated at different levels to learn attention-aware features adaptively within local and global receptive fields. The proposed model was trained on the BraTS-2020 dataset and achieved a dice score of 0.867, 0.813, and 0.787, as well as a sensitivity of 0.93, 0.88, and 0.83 for Whole Tumor, Tumor Core, and Enhancing Tumor, on test dataset respectively. Experimental results show that the proposed HA-RUnet model outperforms the ResUnet and AResUnet base models while having a smaller number of parameters than other state-of-the-art models. Overall, the proposed HA-RUnet model can improve brain tumor segmentation accuracy and facilitate appropriate diagnosis and treatment planning for medical practitioners.     

Analysis of filtration characteristics in submerged microfiltration for drinking water treatment

Hollow fiber membranes have been widely employed for water and wastewater treatments. Nevertheless, understanding the filtration characteristics of hollow fiber membranes is complicated by the axial distributions of transmembrane pressure (TMP) and flux, which are key factors for both fouling control and module design. In this study, model equations to account for different fouling mechanisms were derived to analyze the performance of submerged hollow fiber systems with different conditions in terms of feed water characteristics and membrane material. A series of experiments with synthetic feed and raw water were carried out using hydrophilic and hydrophobic membrane modules. The model successfully fits the experimental results for synthetic feed as well as raw water. The major fouling mechanisms for filtration of raw water using hydrophilic and hydrophobic membranes are identified as cake formation and standard blocking, respectively. The model calculations indicate that the distributions of flux and cake (fouling) resistance are sensitive to the fiber length of the membrane.     

The role of an amorphous carbon layer on a multi-wall carbon nanotube attached atomic force microscope tip in making good electrical contact to a gold electrode

Multi-wall carbon nanotube (MWNT) attached atomic force microscope (AFM) tips (MWNT tips) have good potential for use in AFM lithography. Good conducting MWNT tips are needed in such applications. However, characterizing the conductance of MWNT tips is nontrivial: making a good electrical contact between the MWNT and electrode is difficult. We observed that MWNT tips produced by hydrocarbon-deposition attachment usually do not make good electrical contacts to gold electrodes because of the thin and rough amorphous carbon layer on the MWNT that was unintentionally deposited during the attachment. We found that good contacts can be made if a more amorphous carbon layer is deposited to form a thick and smooth amorphous carbon layer on MWNTs. Good contact was made either by transformation of the amorphous carbon layer into a conducting or peel-off layer, exposing the bare MWNT surface. MWNT tips with an exposed MWNT surface showed the well-known high-current-flowing capacity and the stepped-cutting behavior of bare MWNTs. The peeling-off behavior of a thick amorphous carbon layer may be utilized in producing bare-surfaced MWNT tips that have good conductance and therefore are useful for applications.