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The effects of the electrical resistivity and permeability of conductive paste and magnetic paste materials on the near-field shielding effectiveness (SE) were investigated using strip-line and loop-probe methods. The silver paste of 3.4 x 10^-5Ω·cm of volume resistivity showed more than 30dB of electric field SE and the SE increased as the thickness of conductive layer increased. For the magnetic field SE showed max 60dB as the thickness increased. However, in low frequency below 10MHz, the magnetic field SE was max 3dB in the case of 10µm thickness. Magnetic sheets made of soft magnetic materials having permeability of 200µ showed 11dB of magnetic field SE at 1MHz. The hybrid paste having conductivity of 1.8 x 10^-4Ω·cm and permeability of 23.7µ showed SE of 13.5dB for the magnetic field and 63.9dB for electric field at 10MHz, respectively. The paste having conductivity of 3.7 x 10^-2Ω·cm and permeability of 53.4µ, showed 7.6dB for magnetic field at 10MHz. In low frequency below 10MHz, the permeability had dominant influence on the magnetic field shielding in the near-field region. As the frequency increases, the SE is mainly affected by the conductivity of hybrid pastes.

Stochastic inhomogeneous oxidation is an inherent characteristic of copper (Cu), often hindering color tuning and bandgap engineering of oxides. Coherent control of the interface between metal and metal oxide remains unresolved. We demonstrate coherent propagation of an oxidation front in single-crystal Cu thin film to achieve a full-color spectrum for Cu by precisely controlling its oxide-layer thickness. Grain boundary-free and atomically flat films prepared by atomic-sputtering epitaxy allow tailoring of the oxide layer with an abrupt interface via heat treatment with a suppressed temperature gradient. Color tuning of nearly full-color RGB indices is realized by precise control of oxide-layer thickness; our samples covered ~50.4% of the sRGB color space. The color of copper/copper oxide is realized by the reconstruction of the quantitative yield color from oxide pigment (complex dielectric functions of Cu2O) and light-layer interference (reflectance spectra obtained from the Fresnel equations) to produce structural color. We further demonstrate laser-oxide lithography with micron-scale linewidth and depth through local phase transformation to oxides embedded in the metal, providing spacing necessary for semiconducting transport and optoelectronics functionality., Comment: 38 pages

In this study, Silicon nanoparticles (Si NPs) were homogeneously self-incorporated into melamine–formaldehyde resin microspheres using a facile hydrothermal technique, followed by annealing the precursors to form hollow nitrogen-doped carbon microspheres (hNC MSs) containing approximately 10.8 wt.% Si NPs (Si@hNC MSs). Melamine was directly polymerized with formaldehyde, providing N and C sources for Li-ion battery anodes. Electrochemical tests demonstrated that the Si@hNC MS anode delivered a high reversible capacity of 872 mAh g–1 at a current density of 200 mA g–1 after 360 cycles. The hNC MSs largely limited the Si volumetric changes caused by repeated charging and discharging, resulting in the high electrochemical stability of the Si anode. This work demonstrates that melamine–formaldehyde resins can be used directly as C and N sources and can effectively mitigate the Si volumetric expansion. Moreover, we believe that this unique resin, an effective C source, has promising potential for improving the electrochemical performance of other metal or metal-oxide anodes.

Solution studies have proposed that crystal nucleation can take more complex pathways than previously expected in classical nucleation theory, such as formation of prenucleation clusters or densified amorphous/liquid phases. These findings show that it is possible to separate fluctuations in the different order parameters governing crystal nucleation, that is, density and structure. However, a direct observation of the multipathways from aqueous solutions remains a great challenge because heterogeneous nucleation sites, such as container walls, can prevent these paths. Here, we demonstrate the existence of multiple pathways of nucleation in highly supersaturated aqueous KH2PO4 (KDP) solution using the combination of a containerless device (electrostatic levitation), and in situ micro-Raman and synchrotron X-ray scattering. Specifically, we find that, at an unprecedentedly deep level of supersaturation, a high-concentration KDP solution first transforms into a metastable crystal before reaching stability at room temperature. However, a low-concentration solution, with different local structures, directly transforms into the stable crystal phase. These apparent multiple pathways of crystallization depend on the degree of supersaturation.

Single-crystalline artificial AB-stacked bilayer graphene is formed by aligned transfer of two single-crystalline monolayers on a wafer-scale. The obtained bilayer has a well-defined interface and is electronically equivalent to exfoliated or direct-grown AB-stacked bilayers.

The as-electrospun polymeric lithium titanate nanofibers are crystallized into Li 4 Ti 5 O 12 nanofibers (denoted as LTO NFs) via post-annealing. The LTO NFs are coated with a carbon layer using a glucose polymer via hydrothermal synthesis. The GO layer electrostatically attracts to the positively charged LTO NFs, resulting in the uniform wrapping of individual LTO NFs without aggregation. The introduction of uniformly coated carbon and GO double layers led to an enhanced rate capability (110 mAh g −1 at 20C) and over two orders of magnitude higher diffusion coefficient (D Li = ∼1.04 × 10 −11 cm 2 s −1 ) of the tailored LTO NFs with carbon and GO network compared with those of the pristine LTO NFs. Extended testing for over 100 cycles demonstrates the cyclic stability and Coulombic efficiency of over 99% of this system. These results indicate that the interconnection and networks of LTO NFs through carbon coating and the individual GO wrapping, which facilitates the lithium ion and electron transportation, may show excellent electrochemical performance.

In this work, TiO 2 /SnO 2 hollow hierarchical nanofibers (TiO 2 /SnO 2 hHNFs) are prepared by first synthesizing SnO 2 hollow nanofibers by electrospinning and annealing, then using them as substrates to grow TiO 2 nanorods using a hydrothermal process. The samples are tested under UV irradiation for their photocatalytic activity toward Reactive Black 5 (RB5) and Rhodamine B dyes. The TiO 2 /SnO 2 hHNFs show excellent photocatalytic activity toward the RB5 dye, and perform at level 73 times higher than that of SnO 2 nanofibers and comparable with that of commercially available TiO 2 nanoparticles. The repeatability of the photocatalytic performance of the TiO 2 /SnO 2 hHNFs is quite high; the decolorization capacity decrease to 80.6% of the initial value after 20 cycles. These significant performance improvements are attributed to the increased specific surface area and advantageous energy-band heterostructure of the TiO 2 /SnO 2 hHNFs, which enable effective electron/hole transport and suppresses the recombination of photogenerated electron/hole pairs.

In this study, we have fabricated and studied magnetic domains in the periodic H-mediated Zn0.9Co0.1O (H-ZCO) microdisk structures at room temperature with the MFM technique. The results of MFM show that the z-component of the remanent magnetic moment is uniform even though the value is much smaller than that of the saturation magnetic moment. In the investigation of H-ZCO microdisk arrays in different volumes, the magnetic domains observed on different sizes of the H-ZCO microdisks exhibited the same magnetic domain characteristics, perpendicular magnetization, regardless of the volume. Also, we confirmed that the ferromagnetism in the H-ZnCoO system is mediated by hydrogens with the MFM results of ZnCoO hydrogen injected and dehydrogenated.

The magnetoresistance of a hydrogenated Zn0.8Co0.2O film with an inverted thin film transistor structure was measured at 7 K, in magnetic fields up to 3 T in order to verify the magnetoresistance dependency on carrier density. The gate voltage-dependent magnetoresistance was measured between −15 V and 15 V. A large positive magnetoresistance was identified at all gate biases. Changes in positive gate voltage did not result in significant changes in the magnetoresistance; however, an increase in negative gate voltage resulted in an increase in magnetoresistance and zero field resistivity. The magnetoresistance comprises a positive component, as a result of quantum conductivity correction due to the s–d exchange interaction, and a negative component induced by weak localization. The gate voltage-dependence of the positive and negative magnetoresistances was described by the density of states for ZnCoO:H.

Ultrasmooth single-crystalline metallic thin films provide several key advantages for the fabrication of well-defined and high-resolution plasmonic nanostructures, particularly complex integrated nanocircuits. For this purpose, copper is generally regarded as a poor plasmonic material compared to gold and silver because of its notorious oxidation issues when subjected to air exposure. Here, we report on the use of large-area grain-boundary-free copper films grown epitaxially on sapphire substrates in combination with focused ion beam milling to pattern plasmonic nanostructures with superior quality. The copper surfaces prepared using a single-crystalline copper sputtering target exhibit a very low roughness without any grain boundaries for varying film thicknesses and a strong resistance to oxidation, overcoming the bottleneck in conventional copper film fabrication. Surface plasmon resonance measurements show that improved dielectric constants with higher conductivity and long-term stability can be achieved using the single-crystalline copper films. Plasmonic nanohole arrays patterned from these high-quality films are found to display a stronger field enhancement compared to those made from polycrystalline copper films, thus resulting in an enhanced extraordinary optical transmission performance. This study suggests that our fabrication method is ideally suited for applications in copper-based plasmonic and nanophotonic devices as well as integrated nanocircuits on a large scale.

Realizing laterally continuous, ultraflat silver (Ag) single-crystal films is a significant technological challenge. Ag thin film grown on various hetero-substrates has been used in numerous applications, due to its superior electrical and optical properties. To exploit these properties without degradation and apply these films to high-precision patterning, surface plasmonics, and so on, a high-quality thin film having an ultraflat surface and few grain boundaries is needed. A zinc oxide (ZnO) buffer layer can be used to facilitate the growth of a single-crystalline Ag thin film on a sapphire (Al2O3) substrate. ZnO films deposited on Al2O3 substrates have grain boundaries; however, Ag films grown on ZnO are nearly grain-free and close to single-crystalline quality. This can be explained by the exceptionally small extended atomic distance mismatch, of ~0.08%, between Ag and Al2O3, in which the ninth Ag atom and the eighth Al atom are matched in terms of coherence and periodicity. A modified radio frequency sputtering system with a single-crystal Ag target enabled wafer-scale growth of ultraflat, grain-free Ag films. The proposed approach using a ZnO buffer provides a new method for fabricating Ag films with high adhesion, anti-oxidative stability, and superior optical properties, and allows for easy nano-patterning.

We studied and demonstrated high-performance Ag epoxy composites. A variety of shaped Ag particles were teste to optimize the electrical properties and mechanical reliability. The resulting Ag epoxy composites containing flake-shaped Ag particles showed less than $5 \times 10 ^{-7} \Omega \cdot \mathrm {m}$ electrical conductivity and about $20\mathrm {m} \Omega $ series-resistance of PKG daisy chain, which directly corresponded to the excellent shield effectiveness. The shield effectiveness of resulting EMI shielding layer made of Ag and matrix is as high as 60dB, 65dB, 70dB at 5 $\mu {\mathrm{ m}}$, 10 $\mu {\mathrm{ m}}$, 20 $\mu {\mathrm{ m}}$-thick film, respectively by ASTM standard. We studied that how various factors, such as curing temperature, Ag contents, and film thickness, effects the electrical properties of shielding material and FCBGA package. It was found that the resistivity of conductive shielding material and the series-resistance were affected by the curing temperature than the curing time. Additionally, we demonstrated the electrical properties of AgCu epoxy composites.

In this study, an alumina coated silver core/shell structure particles were prepared through a solgel approach. Various techniques were used to characterize the as-prepared products, including field emission scanning electron microscopy (FE-SEM), field emission transition electron microscopy(FE-TEM), energy-dispersive X-ray spectroscopy (EDS) and thermal transient method. FE-SEM images showed a morphology of alumina coated Ag(ACA) particle and FE-TEM images showed a cross-section of synthesized alumina shell. EDS mapping confirmed that the synthesized shell was composed of Al and O. The thickness of the alumina shell satisfying high insulation resistivity and thermal conductivity was 23.5 nm. The electrical resistance and thermal conductivity of underfill using this alumina coated Ag (ACA) particle was 1.6E12 ?-cm and 1.9 Wm^-1 K^-1. When alumina coated Ag (ACA) particle and alumina were mixed to increase the thermal conductivity, it could be possible to achieve 2.34 Wm^-1 K^-1.

In order to apply silver (Ag) epoxy composites to the FCBGA, we investigated how a variety condition of Ag epoxy composites such as curing temperature, Ag contents, and film thickness effects the electrical resistivity of shielding layer formed by Ag epoxy composites and the series resistance of FCBGA package's daisy chain connected by shielding layer. The resistivity and the series-resistance were more affected by the curing temperature than the curing time. It was found that the optimized Ag contents was 91~92%. With the 91~92% Ag contents, the resistivity showed 3.5×10^5 ?·cm and 21m? of the series-resistance of daisy chain, respectively. We found that the tendency of the resistivity was the same to that of series-resistance of daisy chain. Additionally, we investigated the electrical properties of AgCu epoxy composites.

We report the electrochemical performance of carbon-coated TiO2 nanobarbed fibers (TiO2@C NBFs) as anode material for lithium-ion batteries. The TiO2@C NBFs are composed of TiO2 nanorods grown on TiO2 nanofibers as a core, coated with a carbon shell. These nanostructures form a conductive network showing high capacity and C-rate performance due to fast lithium-ion diffusion and effective electron transfer. The TiO2@C NBFs show a specific reversible capacity of approximately 170 mAh g−1 after 200 cycles at a 0.5 A g−1 current density, and exhibit a discharge rate capability of 4 A g−1 while retaining a capacity of about 70 mAh g−1. The uniformly coated amorphous carbon layer plays an important role to improve the electrical conductivity during the lithiation–delithiation process. Keywords: Li-ion batteries, Anode, Nanostructure, Carbon-coating

Carbon-coated Fe3O4 hollow nanofibers (Fe3O4/C hNFs) as a lithium ion battery anode material are prepared through electrospinning, annealing, and hydrothermal processing. At a high current density of 1000 mAg−1, the template-free Fe3O4/C hNFs exhibit high 1st- and 150th-cycle specific capacities of ∼963 and 978 mAhg−1, respectively. Moreover, Fe3O4/C hNFs have excellent and stable rate capability, compared to that of the Fe3O4 hNFs, and a capacity of 704 mAhg−1 at a current density of 2000 mAg−1. Owing to the carbon layer, the Li-ion diffusion coefficient of the Fe3O4/C hNFs, 8.10 × 10−14 cm2 s−1, is 60 times higher than that (1.33 × 10−15 cm2 s−1) of the Fe3O4 hNFs. These results indicate that Fe3O4/C hNFs may have important implications for developing high performance anodes for next-generation lithium ion batteries.

We synthesized an electrospun SnO2 hollow nanofibers (SnO2 hNFs) coated with carbon and wrapped with graphene oxide layer by simple hydrothermal and electrostatic force method, respectively. Thin carbon layer as electrolyte blocking layer was formed on the SnO2 hNFs by using glucose as a carbon source (SnO2@C hNFs). Also, layers of graphene oxide are wrapped on SnO2@C hNFs by the electrostatic interaction force (SnO2@C@G hNFs). At high C rate, the average capacity of the SnO2@C@G hNFs still kept high capacity comparing with the SnO2 hNFs and SnO2@C hNFs and then increased above 250% at 3 C. It also exhibits a greatly enhanced synergic effect with an extremely high lithium storage capability up to 1,600 mA h g−1 and kept 900 mA h g−1 after 50 cycles benefiting from the advanced structural features.

In this study, we present dye-sensitized solar cells (DSSCs) with improved efficiencies by using SnO2/TiO2 composite photoanodes containing SnO2 at various concentrations. The composites consisted of hollow nanofibers (h-NFs) of SnO2 and TiO2 nanoparticles (NPs). The combination of the large surface area of the NPs and the efficient charge transport in the h-NFs make the use of the SnO2/TiO2 composites advantageous. DSSCs in which composite photoanodes with 50 wt% h-NFs were incorporated showed enhanced efficiencies that were 20% higher than the efficiencies of cells containing TiO2 NP-based photoanodes. These results indicated the improved electron diffusion length and shorter electron transfer time in the composite structures due to the crosslinking between h-NFs and NPs.

Manipulation of spin ordering in oxides without extrinsic contribution is an important issue in current spintronics. This study introduced a mechanism to ascertain the formation of magnetic clusters and the magnetism of a Co-doped ZnO system by temperature-dependent magnetic susceptibility measurements. The measurements demonstrate the possibility of detecting tiny portions of Co clusters that could be created from Co oxides that were undetectable in X-ray diffraction or transmission electron microscopy. By fitting the magnetic susceptibility results, we were also able to ascertain that pure Co-doped ZnO showed a negative Curie–Weiss temperature, implying the existence of antiferromagnetic ordering; however, the Curie–Weiss temperature was gradually increased by intentional hydrogen introduction, with results suggesting that the antiferromagnetic ordering declined proportionally to the hydrogen contents by hydrogen mediation in Co–Co spin ordering and induced ferromagnetism. These results provide a useful methodological approach as well as experimental clues for identifying the origin of magnetism.

Understanding the electronic band structure and density of states (DOS) of a material and their relationship to the associated electronic transport properties is the starting point for optimizing the performance of a device and its technological applications. In a hydrogenated Zn0.8Co0.2O (ZnCoO:H) film with an inverted thin-film transistor structure, we found ambipolar behavior, which is shown in many field-effect devices based on graphene, graphene nanoribbons, and organic semiconductors. In this study, to obtain information on the DOS of ZnCoO:H to explain the ambipolar behavior in terms of the carrier density and type, resistivity and magnetoresistance measurements of a ZnCoO:H film were performed at 5 K. Our proposed DOS representation of ZnCoO:H explains qualitatively the experimental observations of carrier density modulation and ambipolar behavior. First-principles calculations of the DOS of ZnCoO:H were in good agreement with the proposed DOS representation. Through a comparison of first-principles calculations and experimental data, evidence for the existence of Co–H–Co in ZnCoO:H is suggested.

A variety of shaped Ag particles was tested to obtain optimized electrical resistivity and mechanical reliability. We also studied the effect of the spray machine's parameters such as pressure, speed, and droplet size on uniformity of sprayed conductive film. The resulting Ag paste containing flake shaped Ag particles showed about 1×10-7m electrical conductivity. The aspect ratio of top to side coating thickness of the resulting conductive films on EMC mold was 1:0.5~1:0.7, which could be controllable. We found that the best electrical conductivity and mechanical reliability was achieved when only flake shaped Ag were used. Finally, shield effectiveness of resulting EMI shielding film made of Ag and matrix is as high as 60dB, 65dB, 70dB at 5um, 10um, 20um-thick film, respectively by ASTM method.

In this study, we investigated the correlation between thermal conductivity and insulative shell thickness of SiO2 coated Ag (SCA) particles for the thermal filler material in the high performance underfill with focus on improved thermal conductivity. We synthesized the coating of various SiO2 insulation layer on the surface of spherical Ag powder and used them for underfill material formulation to achieve >2 W/mK grade high thermal conductivity capillary underfill. In order to achieve powder distribution with gaussian curve additional spherical alumina was mixed with SCA powder. This mixture blended with epoxy based multifunctional resin matrix. Trend profiling of thermal conductivity and electrical resistivity as a function of SiO2 shell thickness were performed. In addition, correlation of thermal conductivity and viscosity were investigated. Resulting capillary underfill with SCA powders showed 2.14 W/mK thermal conductivity and passed thermal cycling test corresponding to JEDEC LEVEL 3.

As potential high-performance anodes for Li-ion batteries (LIBs), hierarchical heteronanostructures consisting of TiNb

Most of Sea Surveillance Radar(SSR)s which are used in Vessel Traffic Service are Magnetron-based Non-Coherent Method and use the pulse integration technique having a signal to noise ratio enhancement function to satisfy a surveillance performance about target. Especially, Pulse Integration technique has an effect on target serveillance performance through signal to noise ratio, in addition, has an effect to improve a signal interference and noise spike. In this paper, we have a simulati on experiment by using MATLAB simulation tool for appling a pulse integration technique in VTS system using a Non-Coherent radar, and verify an optimum pulse integration technique through out performance analysis between frequently use pulse integration techniques.

The back surface passivation, including the formation of the local contact through the dielectric passivation layer, is regarded as one of the core technologies for enhancing the efficiencies of crystalline silicon solar cells. In this study, the effects of the rear local contact structure on the performances of the cell were simulated by varying the size of the contact area and the distance between the contacts. Because of the symmetry of the current flow in the cell, a simulation domain was defined, and the geometric parameters, such as the rear contact width and the rear contact pitch, were optimized for a high-efficiency solar cell. The behaviors of the cell’s output parameters also depended on the local doping concentration at the rear local contact. The influence of the rear surface recombination velocity on the efficiency of the cell was confirmed by comparing it with the simplified analytic equation for the short circuit-current density in the solar cell.

We report the successful melting and high-temperature liquid density measurements of grain-free single copper and silver crystals, using electrostatic levitation (ESL), for the first time. The melting of Cu and Ag using ESL has not been reported to date due to the unusual charge instability of these samples at high temperatures. We report here an improved levitation stability during heating when using single-crystal specimens. These results will aid the development and further study of industrially important Cu- and Ag-based materials, by indicating the key physical properties of their liquid phases.

High-quality, single-crystal-like Cu2O thin films of various thicknesses (10 nm–45 nm) were prepared at a low temperature (150 °C) by controlling layer-by-layer oxidation of wafer-scale Cu thin films sputtered along the (111) direction using a pure single-crystal Cu target. The cross-sectional images of the thin films reveal high crystallinity of Cu2O layers except for 60° twinning in the sequential stacking order as evidenced by high-resolution transmission electron microscopy, which is consistent with the absence of the photoluminescence (PL) signals arising from atomic-scale vacancies. The optical properties of our Cu2O films were investigated using temperature-dependent PL and Raman spectroscopy. All of the Cu2O thin films exhibit characteristic band-to-band transitions together with the series of yellow excitonic transitions slightly below the fundamental bandgap. The spectral locations for the PL are approximately consistent with those for the bulk counterpart. The excellent optical quality of our Cu2O was further demonstrated by significantly reduced quasi-direct transition that occurs at symmetry-breaking crystal imperfection, which relaxes the stringent momentum conservation rule. We identified the three main Raman scattering modes of the Cu2O thin films, where the two forbidden modes of Γ15(1) and Γ12−+Γ25− are resonantly allowed by the proximity of the incident photon energy to the green bandgap. We believe that our synthesis technique can be utilized for the preparation of single-crystal-like metal oxide thin films at low production temperatures with precise thickness control for the development of novel optoelectronic devices and for the exploration of the nanoscale light-matter interaction as well.

We investigated conversion of Co 3 O 4 to Co nanoclusters through hydrogen reduction. Quantitative analysis is performed on the conversion of Co 3 O 4 to Co metal as a function of hydrogen-injection conditions. Our results reveal that Co 3 O 4 must be completely eliminated to avoid formation of the metal phase in ZnCoO. We also propose a new M–T curve based method for detecting nano-sized Co clusters which are below the detection limit of diffraction techniques. It is also found that the Co phase can be transformed back to the Co 3 O 4 phase through oxygen annealing and that, as a result, the ferromagnetism can be eliminated. These findings are discussed in the context of the origin of ferromagnetism in ZnCoO.

The ferroelectric phase transition in triglycine sulfate ((NH 2 CH 2 COOH) 3 ·H 2 SO 4 , TGS)) crystals, occurring at T C of 322 K, was studied using 1 H and 13 C CP/MAS NMR. From the spin–lattice relaxation time in the rotating frame, T 1 ρ , of 1 H and 13 C, we found that the slopes of the T 1 ρ versus temperature curve changed near T C . In addition, the change of intensities for the protons and carbons NMR signals in the ferroelectric and the paraelectric phases led to the noticeable changes in the environments of proton and carbon in the carboxyl groups. The carboxyl ordering was the dominant factor driving the phase transition. Our study of the 1 H and 13 C spectra showed that the ferroelectric phase transition of TGS is of the order–disorder type due to ordering of the carboxyl groups.

The physical properties of Al1−x Cr x K(SO4)2·12H2O (x = 0, 0.07, and 0.2) were studied as a function of temperature using magic angle spinning nuclear magnetic resonance for 27Al. On the basis of the physical properties of pure AlK(SO4)2·12H2O, the effects of partially replacing Al3+ with Cr3+ ions were examined. Molecular motion changed with the concentration of Cr3+ ions. The relaxation process near 320 K was found to undergo molecular motion as described by the Bloembergen–Purcell–Pound theory. The activation energies, phase transition temperatures, and spin–lattice relaxation times in the rotating frame T 1ρ changed with the concentration of paramagnetic ions.

Amorphous InGaZnO thin films fabricated with various compositions by using the sol-gel method and a spin-coating process show electric properties close to those of an insulator, regardless of the Zn content. However, their conductive properties change after hydrogen treatment, with a high carrier concentration being typical for high Zn content. The poor transmittance and the enhanced electric conductivity after hydrogen treatment is most likely related to the formation of oxygen vacancies. We found that after hydrogen treatment, a change in the Zn content caused changes in the carrier density and the resistivity by factors of 100. Because the change in the Zn content did not influence the properties before hydrogen treatment, we concluded that the carrier density enhancement after hydrogen treatment was due to hydrogen-induced electrons causing enhanced Zn-O coupling rather than to the formation of oxygen vacancies.

To understand the physical properties of Cs3D(SO4)2 single crystals, in which deuterium replaces hydrogen, the temperature dependence of the NMR spectrum and the spin–lattice relaxation times in the laboratory frame, T1, and in the rotating frame, T1ρ, for 2H and 133Cs are investigated using Fourier transform nuclear magnetic resonance spectrometry. Our results for the 2H and 133Cs relaxation times provide no evidence of a phase transition. The strong temperature dependence of the 2H resonance lines is associated with deformation of the H(SO4)2− tetrahedra. Further, T1 and T1ρ for the 2H and 133Cs nuclei are governed by different mechanisms, which we discuss in terms of fast and slow motion.

Our previous studies revealed that co-transplantation of bone marrow stem cells (BMSCs) and adipose-derived stem cells (ADSCs) can enhance bone regeneration and angiogenesis. However, it is unclear which genes are involved in the regulation of osteogenesis and/or angiogenesis during the co-culturing of BMSCs and ADSCs. The expression patterns of genes associated with osteogenesis and/or angiogenesis were analyzed in osteogenesis-induced BMSCs and ADSCs using an oligonucleotide microarray. Significant difference in the expression patterns of several genes were identified from hierarchical clustering and analyzed on co-cultured BMSCs and ADSCs. Angiopoietin-2 (ANGPT2) and activin receptor-like kinase-1 were significantly down-regulated in co-culture than culture of either BMSCs or ADSCs, while fibroblast growth factor-9 was significantly up-regulated in co-culture. The effect of ANGPT2 in osteogenesis-induced BMSCs was validated using recombinant protein and siRNA of ANGPT2. Treatment of the ANGPT2 protein significantly increased the expressions of osteogenic makers and the intensity of Alizarin red-S staining in BMSCs. Down-regulation of ANGPT2 significantly decreased the expression of osteogenic makers. The treatment of ANGPT2 protein to BMSCs induced significantly increased tube formation in Transwell-co-cultured human umbilical vein endothelial cells (HUVECs) compared with untreated control. ANGPT2 siRNA transfection showed the opposite effects. These results suggest that the treatment of ANGPT2 in BMSCs increase osteogenesis and angiogenesis in vitro, and that the enhancement of osteogenesis and angiogenesis in the co-cultured BMSCs and ADSCs seems to be mediated by a mechanism that makes the activation of ANGPT2 unnecessary. These observations provide the first evidence for positive regulation of osteogenesis by ANGPT2 in vitro. J. Cell. Biochem. 118: 2896-2908, 2017. © 2017 Wiley Periodicals, Inc.

There have been many studies of ferromagnetism in ZnCoO, and the results have been controversial. Secondary phases, such as Co oxides and Co metal clusters, in ZnCoO are easily produced during trea...

Cu-doped ZnO (CZO) thin films (0–3 mol% Cu content) were grown on GaN/Al2O3 substrates at 700 °C by using the pulsed laser deposition technique. The XRD results confirmed that the CZO films grew epitaxially and that a few Cu related phases were involved in their growth. The intensity of the green emission peak observed in the photoluminescence (PL) spectra initially increased up to a Cu doping content of 1 mol% but decreased significantly at higher values of the doping content. The saturation magnetization of the CZO film with a Cu content of 0.8 mol% at room temperature was 1.28 emu/cc.

The mixed Na3DxH1−x(SO4)2 crystals grown in this study have a deuterium fraction of 51%, and the phase transitions for Na3D0.51H0.49(SO4)2 were found to occur at 300 K ( = T C 1 ) and 546 K ( = T C 2 ) . The NMR spectra and the relaxation times of 2H and 23Na in Na3D0.51H0.49(SO4)2 crystals were measured as functions of temperature. Although our results for the 2H and 23Na relaxation times provided no evidence of the phase transitions at T C 1 , the 2H and 23Na NMR spectra did change. The phase transitions at 300 K produced changes in the 2H and 23Na NMR spectra that are associated with changes in the atomic positions of the 2H and 23Na ions. The effects of partial deuteration of Na3H(SO4)2 crystals include not only a shift in the phase transition temperature T C but also a change in the local symmetry.

The scientific community has attempted to fabricate superconductors that work at room temperature; however, this goal has not yet been achieved. Considering miniaturization of devices and the requirement of low-power consumption in electronics, it is important to enhance room-temperature conductivity. We prepared the best conductor using crystallization and enhanced its conduction using high-pressure annealing. Single-crystal copper showed a conductivity enhancement of 12–14% after treatment under high pressure and temperature compared with that of oxygen-free copper, which has the highest conductivity for a metal. The contribution of grain boundaries to the Debye temperature was calculated and the phonon excitation was maximized at a lower temperature in grain-free copper. This study aimed to develop a new conductor, in which phonon–electron scattering is reduced at high temperatures. Single-crystal copper could be used for large-scale production of Bitter magnets to generate a high magnetic field and for applications of crystal engineering.