Powder Process with Photoresist for Ceramic Electronic Components

This chapter proposed a patterning process for ceramic electronic components. The proposed process uses a photoresist, and it is combined with the photolithography process and the printing process. By using both technologies, a high-aspect-ratio and fine conductive pattern is achieved because the patterned photoresist hold the filling paste during the dry process. Moreover, a different material pattern in a ceramic sheet can be formed simultaneously when the photoresist covers on the ceramic sheet with a through-hole pattern. The examples of the patterning process and the fabricated pattern are shown. The fine conductive pattern was formed by using a liquid photoresist, and the line width and the thickness were 10.3 and 1.85 μm, respectively. In the ceramic pattern, the conductive paste and low-temperature co-fired ceramic (LTCC) slurry were filled to the ferrite sheet. As a result, the ceramic sheet that had three different materials was achieved. It realizes the miniature ceramic inductor suppressing the minor loop. However, the photoresist process showed some problems with the fine pattern and the different material pattern. These problems are solved by adjusting the viscosity and the composite ratio of the slurry. The optimization of the type and thickness of the photoresist is required

Comparative pore structure analysis of highly porous graphene monoliths treated at different temperatures with adsorption of N-2 at 77.4 K and of Ar at 87.3 K and 77.4 K

We prepared nanoporous graphene monolith of different porosity by high temperature treatment up to 2073 K in Ar. The porosity is comparatively evaluated with N-2 adsorption isotherms at 77.4 K and Ar adsorption isotherms at 87.3 K and 77.4 K. N-2 adsorption at 77.4 K shows an excess adsorption amount below 3 x 10(-3) of the relative pressure which is caused by the quadrupole moment of an N-2 molecule. This effect doesn't give significant influence on the determination of the total surface area from subtracting pore effect (SPE) method, the micropore volume from Dubinin-Radushkevich (DR) method and the total pore volumes from the Gurvitch rule. However, the peak of the micropore size distribution determined by Horvath-Kawazoe (HK) method from N-2 adsorption at 77.4 K shifts to a smaller size than that from Ar adsorption at 87.3 K by 0.05-0.09 nm. (C) 2015 Elsevier Inc. All rights reserved.ArticleMICROPOROUS AND MESOPOROUS MATERIALS. 209:72-78 (2015)journal articl

Milliwatt-Level Electromagnetic Induction-Type MEMS Air Turbine Generator

In this chapter, an electromagnetic induction-type MEMS air turbine generator that combined with the MEMS technology and the multilayer ceramic technology is proposed. Three types of MEMS air turbine generators that included the different bearing systems, shape of the rotor and shape of the magnetic circuits are discussed to achieve the high output power. In the MEMS air turbine, the purpose is to achieve high-speed rotational motion. As a result of the comparison between the different structures, a rim-type rotor and a miniature ball bearing system showed the high rotational speed than a flat-type rotor and a fluid dynamic bearing system. The maximum rotational speed of the fabricated air turbine was 290,135 rpm. Moreover, it is important to introduce the magnetic flux to the magnetic circuit. By the multilayer ceramic technology, the three-dimensional coil in miniature monolithic structure was fabricated. The magnetic core that was designed to introduce the magnetic flux showed the low magnetic flux loss. The fabricated MEMS air turbine and the multilayer ceramic magnetic circuit were combined, and the miniature electromagnetic induction-type generator was achieved. The output power was 2.41 mVA, when the load resistance and the output voltage were 8 Ω and 139 mV, respectively

Robust graphene-based monoliths of homogeneous ultramicroporosity

Graphite oxide (GO) and graphene monoliths were prepared using the unidirectional freezing of GO water suspension. These materials were saturated with a poly(ammonium-4-styrene sulfonate) water soluble polymer and then carbonized at 1123 K. This process increases significantly the materials strength and density. A uniform deposition of the polymer-derived carbon on the external layers of the graphene sheets of the monolith was found. The carbon from polymer not only provided more contact between the graphene sheets but also apparently increased the overall graphitization level (based on Raman spectra). The modification decreased the electrical resistance by one order of magnitude compared to that of the graphene monolith. N-2 adsorption at 77 K showed that the thus-treated graphene monoliths have quite homogenous pores with the pore width of 0.7 nm. These pores, combined with large transport pores, and conductive properties make the monoliths tested the promising materials for separation, energy storage, and/or gas sensing. The tunability of the properties and pore structure of the robust graphene ultramicroporous monolith through the control of chemistry of the initial GO monolith was shown. (C) 2015 Elsevier Ltd. All rights reserved.ArticleCARBON. 87:87-97 (2015)journal articl

Gait Generation of Multilegged Robots by using Hardware Artificial Neural Networks

Living organisms can act autonomously because biological neural networks process the environmental information in continuous time. Therefore, living organisms have inspired many applications of autonomous control to small-sized robots. In this chapter, a small-sized robot is controlled by a hardware artificial neural network (ANN) without software programs. Previously, the authors constructed a multilegged walking robot. The link mechanism of the limbs was designed to reduce the number of actuators. The current paper describes the basic characteristics of hardware ANNs that generate the gait for multilegged robots. The pulses emitted by the hardware ANN generate oscillating patterns of electrical activity. The pulse-type hardware ANN model has the basic features of a class II neuron model, which behaves like a resonator. Thus, gait generation by the hardware ANNs mimics the synchronization phenomena in biological neural networks. Consequently, our constructed hardware ANNs can generate multilegged robot gaits without requiring software programs

<ORIGINAL>A prospective randomized clinical study on the efficacy of CO_2 lasers on initial stage endodontics

The purpose of this study was to evaluate the clinical efficacy of the CO_2 laser in a prospective randomized trial. A total of 112 teeth in 112 patients, previously treated pulpectomy procedures were gathered and randomly divided into two groups composed of 56. Irradiation was performed on one group and non-irradiation forms of treatment were performed on the other group. On the first group of teeth, root canal enlargement was done and followed by exposure of the canal to a CO_2 laser light (5W, 200msec) using 3 cycles each at a rate of 15 seconds per cycle. The second group was not exposed to laser light following root canal enlargement. The laser was applied on the root canal for a controlled period of time. On the day following pulpectomy, a statistically significant (p < 0.05) fewer number of patients observed pain in the irradiation group compared to the non-irradiation group. The treatment times and the total treatment days in the irradiation group are shorter than in the non-irradiation group (p < 0.05). Multivariate analysis showed that the laser treatment was significantly associated with treatment times. This study shows that the degree of oral pain was greatly reduced in patients who underwent laser irradiation as compared to these who did not. Our study suggests that the use of laser treatment provide significant short-term improvement compared to conventional forms of treatment performed during pulpectomy

Noticeable Reverse Shift in the Melting Temperatures of Benzene and Carbon Tetrachloride Confined within the Micropores and Mesopores of Hydrophobic Carbons

Carbon aerogels contain both mesopores and micropores. In this study, benzene/CCl4 was adsorbed in the pores of carbon aerogels (both mesopores and micropores) and their phase behaviours were examined using differential scanning calorimetry. The bulk solid benzene melted at 278 K and the melting temperatures of benzene confined inside the mesopores and micropores of carbon aerogels were 258 and 293 K, respectively. Although the melting temperature depression of condensates in mesopores is well known, the observed elevation of the melting temperature for micropores is very limited in the strongly interacted system. Similar melting behaviours were observed for the confined CCl4; depression by 45 K in mesopores and elevation by 48 K in micropores showed about two times the change as compared with that of confined benzene.ArticleADSORPTION SCIENCE & TECHNOLOGY. 31(2-3):145-151 (2013)journal articl

Sol-gel chemistry mediated Zn/Al-based complex dispersant for SWCNT in water without foam formation

We report a bimetallic Zn/Al complex as an efficient inorganic dispersant for SWCNT, synthesized from Zn(CH3COO)(2) and Al(NO3)(3). The Zn/Al complex shows more than four times greater efficiency at dispersing SWCNT than widely used surfactants (CTAB and SDS). Besides remarkable dispersibility, the Zn/Al complex does not foam upon any shaking treatment and it can be used just after quick dissolution of the powdered form, which is a marked advantage over surfactants. The Zn/Al complex, containing amorphous Al(CH3COO)(3) and a complex of Zn2+ and NO3- ions, should have a unique dispersion mechanism, differing from the surfactants. Al(CH3COO)(3) has higher affinity for SWCNT than ions, adsorbing onto its surface in the first layer and attracting Zn2+ and NO3- ions. Charge transfer interactions between the Zn/Al complex and SWCNT, as evidenced by optical absorption spectroscopy, should induce a charge on SWCNT; the zeta potential of such coated SWCNT was +55 mV, indicating a high dispersion stability in aqueous media. Hence, the Zn/Al complex can widen the applications of SWCNT to various technologies such as the transparent and conductive films, as well as high performance composite polymers. (C) 2015 Elsevier Ltd. All rights reserved.ArticleCARBON. 94:518-523 (2015)journal articl