Hosokawa Powder Technology Foundation ANNUAL REPORT
Online ISSN : 2189-4663
ISSN-L : 2189-4663
Volume 24
Showing 1-38 articles out of 38 articles from the selected issue
Preliminaries
Research Grant Report
  • Motoyuki IIJIMA
    2016 Volume 24 Pages 19-23
    Published: 2016
    Released: June 10, 2017
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS

    In order to realize the control of dispersion state and the alignment structure of multi-component particles in highly concentrated metal pastes, a processing route to simultaneously attach functional nanoparticles on metal fine particles and to stabilize metal particles in solvents has established. Using SiO2 nanoparticles as model nanoparticles, their surface was first modified with a complex of polyethyleneimine and oleic acid (PEI-OA), which is expected to be a useful dispersant that can be attached on various species of particles and to stabilize particles in non-aqueous solvents. Then, bare Ni fine particles were simply added into the PEI-OA modified SiO2 nanoparticle/toluene dispersion. Based on this simple mixing process, it was found that surface modified SiO2 nanoparticles can attached on Ni fine particles through PEI-OA and the obtained Ni/SiO2 composites can be stabilized in toluene even under highly concentrated conditions.

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  • Koichiro OGATA
    2016 Volume 24 Pages 24-29
    Published: 2016
    Released: June 10, 2017
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    This study has examined the evaluation of the cohesive powder flow using the test of powder discharge by the additional pressure of the air flow. As the experimental condition, three kinds of Calcium hydroxide was used and the interstitial air pressure and the initial void fraction were varied. According to the results of powder discharge, it could be obtained the following main result: (1) A state of powder flow could be classified to the dischargeable, the transient and the non dischargeable. (2) A cohesiveness of three kinds of Calcium hydroxide have revealed from the ration of estimated cohesive force to gravity force. (3) The difference in flowability of three powders could be indicated clearly from the relationship between the ration of estimated cohesive force to gravity force. As the result, the low flowability of powder was obtained when the ration of cohesive force to gravity force is large.

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  • Chiaki OGINO
    2016 Volume 24 Pages 30-34
    Published: 2016
    Released: June 10, 2017
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    Radiosensizing therapy, combining radiotherapy and an agent for amplifying radiation, have an advantage for therapy of low-oxygen cancer including pancreatic. In our recent study, the hydrogen peroxide treatment of titanium dioxide nanoparticles induced titanium peroxide nanoparticle (PAATiOx), and it was suggested to use as radiosensitizing agent for radiotherapy. By this combination, the apparent therapeutic positive effect was observed in vivo study of human pancreatic xenograft mice. However, it can’t be said that it has a high usefulness for radiosensizing therapy. So we prepared antibody modification PAATiOx (PAATiOx/1a), the antibody is the variable domain of a camelid heavy chain-only antibody (1a), which has high affinity to EGFR, expressed in various cancer cells. As a result, PAATiOx/1a with X-ray treatment showed more cytotoxicity than PAATiOx with equivalent dose of X-ray irradiation in vitro and in vivo. Since this study showed that PAATiOx/1a could target EGFR-expressing cells, we would use this particle as a drug delivery carrier for various cancer cells expressing EGFR.

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  • Ken-ichi KAKIMOTO
    2016 Volume 24 Pages 35-39
    Published: 2016
    Released: June 10, 2017
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS

    Alkali niobate ceramic system based on (Li, Na, K)NbO3 (LNKN) has been regarded as a leading candidate for lead-free piezoelectric ceramics in which a high Curie temperature and excellent piezoelectric properties can be expected. Our current interests are focused to well-designed processing and microstructure control; however, literatures on the above-mentioned topics have remained essentially insufficient to date, although this is a crucial subject for the development of lead-free piezoceramics for harsh-environments. This study, therefore, was devoted to a new powder processing which started from fine control of Nb2O5 raw materials. As a result, the engineering of the controlled particle size and its size distribution was succeeded to realize low-temperature sintering for LNKN ceramics with high density. This result also introduced a precise evaluation of their ferroelectric domain structures under applied electrical field. The obtained facts were emphasized to prepare high-performance LNKN ceramics toward future industrial application.

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  • Kohsaku KAWAKAMI
    2016 Volume 24 Pages 40-44
    Published: 2016
    Released: June 10, 2017
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    Due to their high safety to human bodies, phospholipids are widely used as additives for pharmaceutical and cosmetic products. In fact, liposome is a representative carrier for drug delivery system. However, industrial production and quality control of liposome is not easy because of its non-equilibrium nature, and its effective use was limited to injectable formulations. We have developed a method for preparing mesoporous phospholipid particle (MPP). Due to its simplicity, industrial production of MPP is expected to be easy. MPP is applicable for various solid dosage forms. In this article, its function as a carrier for oral delivery of poorly soluble drug is introduced. MPP is expected to be a novel DDS platform carrier.

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  • Shoichi KIKUCHI
    2016 Volume 24 Pages 45-48
    Published: 2016
    Released: June 10, 2017
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    Titanium alloy (Ti-6Al-4V) with bimodal “harmonic structure”, which consists of the coarse-grained structure surrounded by the network structure with fine grains, was fabricated by mechanical milling (MM) and spark plasma sintering (SPS) to achieve high strength and good plasticity. The microstructure of the MM-processed powder and the sintered compacts were characterized using a micro-Vickers hardness tester, scanning electron microscope and an electron backscatter diffraction technique. Harmonic structure was formed in the sintered Ti-6Al-4V compacts prepared from the MM-processed powders with fine grains at its surface. The Ti-6Al-4V alloy with harmonic structure exhibited high tensile strength and good plasticity. The effects of the harmonic structure on the 4-point bending fatigue properties of Ti-6Al-4V alloy were investigated. The compacts with harmonic structure exhibited higher fatigue strength compared to the conventional coarse-grained material prepared from as-received initial powders. This was because the Ti-6Al-4V alloy with harmonic structure had higher tensile strength and hardness. Moreover, fatigue fracture mechanism of the Ti-6Al-4V alloy with harmonic structure was discussed based on the fractography and crystallography. As results of observing and analyzing the fracture surfaces, the Ti-6Al-4V alloy with harmonic structure failed from the coarse grain in the harmonic structure.

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  • Yoshiyuki KOMODA
    2016 Volume 24 Pages 49-55
    Published: 2016
    Released: June 10, 2017
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    The change of rheology of concentrated micro-particle slurry with the addition of nano-particles has been studied. Aggregated micro-particles dominate the rheological properties, which is not change by the addition of nano-particles. In contrast, the rheological characteristics of dispersed micro-particles slurry could be significantly changed by nano-particles. In the case of the slurry of dispersed silica micro-particles and aggregated alumina nano-particles, the gap between micro-particles are stuck by nano-particle aggregates, resulting in a highly elastic or gel like rheological behavior. At 50 vol% of particle content, only 0.01 vol% nano-particle could drastically increase the slurry viscosity. On the other hand, silica nano-particles are attached on the surface of silica micro-particles and the mixed slurry still showed Newtonian behavior. However, under high shear rate condition, nano-particles are released from micro-particles and form clusters, which again stuck between micro-particles. As a result, the mixture showed discontinuous shear-thickening behavior.

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  • Isao SHITANDA
    2016 Volume 24 Pages 56-60
    Published: 2016
    Released: June 10, 2017
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    Paper-based biofuel cell have been attracted as a potential application as energy harvesting power sources in Internet of things (IoT) field. In the present study, we newly developed screen-printed paper-based wearable biofuel cell array fabricated by using MgO-templated carbon ink. The paper-based biofuel cell array exhibited a maximum power density of 1 mW. The present flexible paper-based biofuel cell is highly applicable to the development of low cost, flexible, ubiquitous energy devices.

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  • Shintato TAKEUCHI
    2016 Volume 24 Pages 61-65
    Published: 2016
    Released: June 10, 2017
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    Heat transfer problem in solid-dispersed two-phase flow is numerically studied. Temperature gradient within the finite-sized particles and inter-particle heat flux due to collisions are considered, and those effects on the flow structure and heat transfer are discussed. The interfacial flux model is extended to incorporate the heat conduction due to inter-particle contacts, based on 2-D and axisymmetric contact heat resistance solutions. The method is applied to 2-D and 3-D natural convection problems including multiple particles in a confined domain. Under high solid volume fraction conditions, the particles are observed to form densely concentrated regions, where heat flow tends to channel through the contacting points. In three-dimensional solid-dispersed flows, by decomposing the heat flux into the contributions of the convection and conduction, the change of the major heat transfer mode is studied for different solid volume fractions and conductivity ratios.

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  • Yukikazu TAKEOKA
    2016 Volume 24 Pages 66-69
    Published: 2016
    Released: June 10, 2017
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS

    Generally, we have an image that the structural colored material changes its hue depending on the direction of light irradiation and the viewing direction. I found that structural colored materials of various hues without angle dependence could be prepared from white and black materials. As a material, silica, titanium oxide, magnetite, and polymers can be used. We can obtain non-toxic and non-fading color materials at low cost using our materials, because the structural colored materials are composed of environment and people-friendly inexpensive materials. Moreover, because black materials exhibiting various functions such as conductivity, magnetic properties, photo-responsiveness, etc., functional colored materials utilizing these functions may be obtained.

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  • Yoshiko TSUJI
    2016 Volume 24 Pages 70-73
    Published: 2016
    Released: June 10, 2017
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    Sublimation purification is the most common method for the purification of low molecular organic semiconductor materials. Purification rate enhancement and high purity production in sublimation process are required in order to increase the overall throughput of electronic devices manufacturing process. In commercially practiced sublimation purification, large amount of raw materials, which are mostly powder, are purified at once and heat transfer within powder bed in the vacuum process is very slow. For these reasons, the rate limiting step is predicted to be steps within the bed of raw material such as diffusion in solid, heat and mass transfer within the bed, and outward diffusion from particle.In this work, two materials were used as model substances for sublimation process in vertical tube chamber, one was anthracene in the non-equilibrium state and the other was pentacene in the equilibrium state. We developed the mathematical model that takes into account conjugate heat and mass transfer within the cylindrical particle bed. The sublimation rate of pentacene in the equilibrium state did not depend on bed height, considering that the sublimation rate was controlled by steps outside the bed. In contrast, the sublimation rate of anthracene in the non-equilibrium state became smaller when bed height increased, considering that the sublimation rate was controlled by steps within the bed.

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  • Manabu TOKESHI
    2016 Volume 24 Pages 74-78
    Published: 2016
    Released: June 10, 2017
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    In order to elucidate the formation mechanism of lipid nanoparticles in microfluidic devices, we investigated the formation behavior of lipid nanoparticles in microfluidic devices with a staggered herringbone micromixer structure. The microfluidic devices were fabricated with varying the staggered herringbone micromixer cycle numbers to confirm the effect of mixing the solutions on the LNP formation. 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) was dissolved in ethanol to obtain a concentration of 10 mg/mL lipid solution. 154 mM NaCl was used for the aqueous solution. The size of the lipid nanoparticles was analyzed by dynamic light scattering. From the obtained results, we assumed that the rapid decrease of ethanol concentration to its critical concentration was essential to form lipid nanoparticles.

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  • Naoki NODA
    2016 Volume 24 Pages 79-84
    Published: 2016
    Released: June 10, 2017
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    Electrostatic precipitator (ESP) is used as a major dust collection equipment in various industries. As the environmental influence of fine particle such as PM2.5 in the atmosphere is focused recently, the improvement of the collection efficiency of fine particle on ESP is desired. The collection efficiency of ESP is affected by dust properties such as particle diameter and the electric resistivity of the dust. In this study, a fine particle collection efficiency of ESP and an improvement method of the separation characteristics of fine particle by gas flow control on ESP in a pulverized coal combustion boiler is investigated. It is estimated that the control of gas flow pattern in ESP is one of the effective method for improvement of ESP.

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  • Taichi FURUKAWA
    2016 Volume 24 Pages 85-91
    Published: 2016
    Released: June 10, 2017
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS

    Cathodoluminescence (CL) microscopy, which is a combination of optical microscopy and electron microscopy, has the potential to realize multi-color bioimaging with nanoscale spatial resolution. To achieve this biological CL imaging, development of small nanophosphors with similar size to protein molecules and bright CL nanophosphors is indispensable. In this research, we developed nanophosphors for CL bioimaging using laser ablation method and homogeneous precipitation method. The size distribution of laser-ablated nanophosphors was large, and the CL intensity of single nanophosphor with size of a few tens nm was not enough to image. In homogeneous precipitation method, mono-dispersed nanophosphors with size of about 40 nm were obtained with small size distribution. Improvement of CL intensity was also achieved with varying concentration of rare-earth ions, calcination temperature, and addition of co-doing ions.

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  • Kazuhiko MAEDA
    2016 Volume 24 Pages 92-97
    Published: 2016
    Released: June 10, 2017
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS

    TiO2 is a well-known semiconductor photocatalyst, but the wide band-gap restricts its application to solar energy conversion. We demonstrated that tantalum and nitrogen-codoped rutile TiO2 was an active photocatalyst for water oxidation under visible light. It achieved overall water splitting in combination with a H2-evolution photocatalyst of SrTiO3:Rh and an Fe3+/Fe2+ redox couple even under simulated sunlight. We also found that rutile TiO2 modified with cobalt hydroxide nanoclusters was capable of harvesting visible light with wavelengths of up to 850 nm, and photocatalyzing water oxidation to produce molecular O2. To our knowledge, this system provides the first demonstration of a photocatalytic material capable of water oxidation upon excitation by visible light up to such a long wavelength, even with the use of earth-abundant elements only.

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  • Tatsuo MARUYAMA
    2016 Volume 24 Pages 98-102
    Published: 2016
    Released: June 10, 2017
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    There are no reports on liquid–liquid extraction of solid nanoparticles based on size- or surface- selective separation. In the present study, we examined phase-transfer of semiconductor nanoparticles in surface- and size- selective manners using reverse micelles and a DNA surfactant. We adopted DNA-functionalized CdTe quantum dots (DNA-QDs) as target solid nanoparticles. The DNA surfactant recognized DNA tethered to QDs and transferred the DNA-QDs to an organic phase via the DNA hybridization. These were successfully applied in the liquid–liquid extraction of DNA-QDs from an aqueous phase to an organic phase in both surface- and size-selective manners. I investigated the size-dependent extraction of the DNA-QDs from a mixture of DNA-QDs with different diameters (4 and 5.5 nm). These two types of DNA-QDs were added to an aqueous phase containing DNA surfactant, followed by the addition of an organic phase containing DLPC and 1-hexanol. Following gentle stirring for 3 h, DNA-QDs with QDs of size 4 nm were preferentially extracted over DNA-QDs with QDs of size 5.5 nm, which were barely extracted. Thus, the present system affords size-selective extraction of DNA-QDs from a mixture of DNA-QDs to an organic phase.

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  • Yoshihide MAWATARI
    2016 Volume 24 Pages 103-108
    Published: 2016
    Released: June 10, 2017
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS

    The characteristics of particle motion behavior in a gas-solid fluidized bed for fine cohesive particle under mechanical bed vibration were experimentally investigated. In this study, spherical zirconia particle whose mean diameter and density were 8.2 μm and 5680 kg/m3 was used as a fluidizing material. Vertical vibration was added to the fluidized bed and the vibration parameters (vibration frequency and amplitude) were varied. From the observation of particle flow patterns in the bed, the flow pattern in the bed was gradually changed with the magnitudes of the gas flow rate and the vibration parameters. When the vibration amplitude was higher than a certain magnitude, the bed surface formed inclined plane while the particles migrated on the inclined bed surface. Then, with further higher vibration amplitudes, the heap shape was formed on the bed surface with particle migration. The particle migration velocity was increased as the vibration amplitude increased. In this study, we successfully obtained the map of flow pattern for bed of fine particle under mechanical bed vibrating condition.

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  • Hiroyuki MIKI
    2016 Volume 24 Pages 109-114
    Published: 2016
    Released: June 10, 2017
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    A new method of solidifying metal powder by the compression and shearing method under room temperature was developed. In the solidified specimen, recrystallization is suppressed, so that the nano-scale crystal grains are remaining. The hardness of the solidified specimen prepared by this process is increased relative to materials prepared by other methods. During the process, metal powders are solidified by the enforced plastic flow and the external heating is not required. The direct molding from powder is the industrially effective technique from the viewpoint of productivity improvement.In this study, the alloying process of the dissimilar metal joint using compression shearing method at room temperature was investigated. Joint material of copper (Cu), aluminum (Al) and zinc (Zn) was molded, and the crystal and the mechanical characteristics were evaluated. The bonding property between different kind of metals by the compression and shearing method under room temperature and the possibility of the machine part application of the composite were discussed.

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  • Shoji MORI
    2016 Volume 24 Pages 115-118
    Published: 2016
    Released: June 10, 2017
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS

    The critical heat flux (CHF) enhancement is of great concern to many engineers and researchers. In the previous study, the saturated pool boiling CHF using a honeycomb porous plate shows a significant enhancement compared to a plain surface. Recently, numerous studies of the CHF enhancement by nanofluid have been reported. Therefore it is anticipated that the CHF might be enhanced greatly by combining these two elements. In the present paper, the effects of a honeycomb porous plate and nanofluid on the CHF were investigated experimentally.

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  • Shintaro MORISADA
    2016 Volume 24 Pages 119-124
    Published: 2016
    Released: June 10, 2017
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS

    Poly(N-isopropylacrylamide) (PNIPAM) microgels were synthesized by emulsion polymerization using sodium dodecyl sulfate (SDS). After removal of SDS by dialysis, the surface tension of the PNIPAM microgel dispersion was measured by the pendant drop method, and it was found that the surface tension of the microgel dispersion is much smaller than that of water at 25°C. Also, the stability of the foams generated by nitrogen bubbling through the PNIPAM microgel dispersion was investigated. At 25°C, the stable foam was observed, while no stable foam was formed at 60°C. Moreover, the stable foam prepared at 25°C quickly disappeared when the temperature was changed to 60°C. These results suggest that the PNIPAM microgel has a temperature-responsive surface-activity.

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  • Kunikazu MORIBE
    2016 Volume 24 Pages 125-128
    Published: 2016
    Released: June 10, 2017
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    Aggregation behavior of a pharmaceutical drug in nanoparticles was directly evaluated using atomic force microscopy (AFM) by topographic image analysis and by force curve measurements in water. A ternary spray-dried sample (SPD) was prepared by spray drying the organic solvent containing probucol (PBC), hypromellose (HPMC), and sodium dodecyl sulfate (SDS). The amorphization of PBC in the ternary SPD was confirmed by solid-state 13C NMR measurement. A nanosuspension containing quite small particles of 25 nm was prepared after dispersion of the ternary SPD into water. Solution-state 1H NMR measurements revealed that a portion of HPMC coexisted with PBC as a mixed state in the freshly prepared nanosuspension. After storing the nanosuspension at 25°C, a gradual increase in the size of the nanoparticles was observed. AFM enabled the direct observation of the morphology and agglomeration behavior of the nanoparticles in water. AFM force–distance curves changed depending on the storage period. The stiffness increase was attributed to changes in the molecular state of PBC from the amorphous to the crystal state.

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  • Seiji YAMASHITA
    2016 Volume 24 Pages 129-132
    Published: 2016
    Released: June 10, 2017
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS

    Layered metal hydroxide salts powder have anisotropic surface charge on the plate-like particles derived from their layered crystal structure. The aggregation structure of layered metal hydroxide in the water phase were specific such as cardhouse structure because of surface electrostatic charge distribution depend on the pH condition. We suggest the partly hetero coagulation structure using the electrostatic charge distribution on the surface of layered metal hydroxide particle as newly anisotropic composite process. In this study, Mg-based layered hydroxide salt particle, which was our developed multi-step chemical heat storage material, and sub-micron Al2O3 particles were used as hetero coagulation particle for the reaction packing bed on chemical heat storage system. The hetero coagulation structure of Mg-LHS and Al2O3 particles was generated at pH 7. It was found that hetero coagulation particles was effective to make packing bed for high reaction speed and high thermal storage density. It was assumed that packing bed of hetero coagulation powder have porous structure with high density and the pass structure of water vapor.

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  • Shinpei YAMAMOTO
    2016 Volume 24 Pages 133-137
    Published: 2016
    Released: June 10, 2017
    RESEARCH REPORT / TECHNICAL REPORT FREE ACCESS

    Nitric oxide (NO) is a major signalling molecule in neural, circulatory and immune systems. The biological effects of NO have been shown to be highly site, concentration and dosage dependent. This project aims to develop a system which enables controlled release of NO by an external magnetic field, to which tissues are almost transparent.

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