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The crystallization of the magma ocean resulted in the present layered structure of the Earth’s mantle. An open question is the electronic spin state of iron in bridgmanite (the most abundant mineral on Earth) crystallized from a deep magma ocean, which has been neglected in the crystallization history of the entire magma ocean. Here, we performed energy-domain synchrotron Mössbauer spectroscopy measurements on two bridgmanite samples synthesized at different pressures using the same starting material (Mg0.78Fe0.13Al0.11Si0.94O3). The obtained Mössbauer spectra showed no evidence of low-spin ferric iron (Fe3+) from the bridgmanite sample synthesized at relatively low pressure of 25 gigapascals, while that directly synthesized at a higher pressure of 80 gigapascals contained a relatively large amount. This difference ought to derive from the large kinetic barrier of Fe3+ rearranging from pseudo-dodecahedral to octahedral sites with the high-spin to low-spin transition in experiments. Our results indicate a certain amount of low-spin Fe3+ in the lower mantle bridgmanite crystallized from an ancient magma ocean. We therefore conclude that primordial bridgmanite with low-spin Fe3+ dominated the deeper part of an ancient lower mantle, which would contribute to lower mantle heterogeneity preservation and call for modification of the terrestrial mantle thermal evolution scenarios.

The externally heated diamond anvil cell (EHDAC) conducts high pressure and temperature experiments with spatial uniformity and temporal stability. These are conventionally combined with various spectroscopies and x-ray diffraction measurements. EHDAC techniques perform Joule heating on a heater placed close to or directly in contact with diamond anvils. However, the electrical wiring and heater required for Joule heating complicate EHDAC setups, hindering easy access for the measurement of physical properties. This study proposes an EHDAC technique using laser- instead of Joule-heating. We successfully achieved temperatures reaching 900 K by applying heat to diamond anvils through laser-heating of the gaskets with thermally insulating anvil seats. To test this setup, we measured the melting temperature of H2O ice VII, which was consistent with previous studies. We also measured the high-pressure and temperature impedance of H2O VII and verified the capability of electrical resistivity measurements in this setup. This technique allows various physical property measurements owing to its simple setup required for externally laser-heated diamond anvil cell experiments. The unique characteristics of this heating technique are that (1) no heaters or wiring are required, (2) it exhibits the most efficient heating among EHDAC studies, (3) it maintains the DAC body at room temperature, and (4) diamond anvils do not detach from anvil seats after the EHDAC experiment. This method significantly simplifies the experimental setup, which allows much easier access to various physical property measurements using an EHDAC.

Hydrogen could be an important light element in planetary cores, but its effect on phase diagrams of iron alloys is not well known because the solubility of H in Fe is minimal at ambient pressure and high-pressure experiments on H-bearing systems have been challenging. Considering that silicon can be another major light element in planetary cores, here we performed melting experiments on the Fe-Si-H system at ~50 GPa and obtained the ternary liquidus phase relations and the solid/liquid partition coefficient, D of Si and H based on in-situ high-pressure X-ray diffraction measurements and ex-situ chemical and textural characterizations on recovered samples. Liquid crystallized hexagonal close-packed (hcp) (Fe0.93Si0.07)H0.25, which explains the observed density and velocities of the Earth’s solid inner core. The relatively high DSi = 0.94(4) and DH = 0.70(12) suggest that in addition to Si and H, the liquid outer core includes other light elements such as O, which is least partitioned into solid Fe and can thus explain the density difference between the outer and inner core. H and O, as well as Si, are likely to be major core light elements, supporting the sequestration of a large amount of water in the Earth’s core.

The electrical conductivity (EC) of minerals found on Earth and throughout the solar system is a fundamental transport property that is used to understand various dynamical phenomena in planetary interiors. High-pressure and high-temperature ( P–T) EC measurements are also an important tool for observing phase transitions. Impedance measurements can accurately measure the EC of a nonmetallic sample. In previous measurements under static conditions using a laser-heated diamond-anvil cell (LHDAC), only direct current resistance is measured, but this method overestimates the bulk sample resistance. Moreover, the previous methodology could only be applied to nontransparent samples in an LHDAC using infrared lasers, limiting the range of measurable composition. To the best of our knowledge, no in situ high- P–T EC measurements of transparent materials have been reported using LHDAC techniques. We developed a novel impedance measurement technique under high- P–T conditions in an LHDAC that applies to transparent samples. As a validation, we measured the EC of Mg0.9Fe0.1SiO3 bridgmanite up to 51 GPa and 2000 K and found that the results are consistent with those of previous studies. We also measured the EC values of sodium chloride to compare with those of previous studies, as well as those of cubic boron nitride and zirconia cement to quantify how well they insulate under high P–T conditions. This is the first report of the impedance and EC measurements of transparent minerals in an LHDAC, which allows the measurement of Fe-poor/-free materials, including the major constituents of the interiors of gas giants and icy planets, under extreme conditions.

Thermal conductivity of bridgmanite (Bdg) is the important physical property controlling the heat transfer inside the Earth. Here we report room temperature lattice thermal conductivity of (Fe,Al)-bearing Bdg with chemical compositions of Mg0.848Fe0.090Al0.206Si0.856O3 and Mg0.718Fe0.123Al0.281Si0.878O3 measured up to 125 GPa and 74 GPa, respectively, using the pulsed light heating thermoreflectance technique in a diamond anvil cell. We found that the lattice thermal conductivity of these Bdg samples show abnormal reduction in the pressure range of 20-40 GPa at 300 K, which is probably due to the spin transition of Fe3+ in octahedral Si-site (B-site). We propose that the lattice thermal conductivity of Bdg is reduced by 46 ± 16% when Fe is in the mixed spin state, which may form a thermal insulating layer in the Earth's mid lower mantle. In addition, we provide a thermal conductivity model of Bdg, taking into account the effect of compositional difference and the spin transition of Fe. Our conductivity model indicates that the thermal conductivity of Bdg in the pyrolitic lower mantle is more than twice as high as that in the descending MORB, which is likely to create heterogeneity of lateral heat flux through the Earth's core-mantle boundary.

We measured the lattice thermal conductivities of Fe0.98O wustite and iron-rich (Mg,Fe)O magnesiowustite using the pulsed light heating thermoreflectance technique with a diamond anvil cell up to 61 GPa at 300 K. We found that the thermal conductivity of wustite does not show a monotonic increase as a function of pressure, contrary to that of MgO periclase. Rocksalt (B1) to rhombohedral B1 transition is likely to induce an abnormal pressure response in the conductivity of wustite. Our results also show that magnesiowustite has a lower conductivity than that of MgO and FeO endmembers due to a strong iron impurity effect, which is well reproduced by a model considering phonon-impurity scattering in a binary solid solution.

The valence and spin states of Fe in (Fe,Al)-bearing bridgmanite (bdg) affect its physical properties, which is important for the interpretation of geophysical observations. Currently, tens of studies on the compressibility and spin states of Fe-bearing bdg have been reported. A consensus is that Fe-bearing bdg shows spin transition, which affects its elastic parameters. However, there is a conflict between reports on the compressibility and spin states of (Fe,Al)-bearing bdg in experiments using samples pre-synthesized in a multi-anvil apparatus (MA), and samples directly synthesized in a diamond anvil cell (DAC). There are no reports showing evidence of spin transition of Fe in compression experiments using (Fe,Al)-bearing bdg samples pre-synthesized in a MA, while those synthesized at relatively high pressure (at least above 45 GPa) in a DAC all exhibited the spin transition. Here, we performed synchrotron X-ray diffraction measurements on Mg0.85Fe0.09Al0.21Si0.86O3 and Mg0.85Fe0.14Al0.05Si0.96O3 bdg synthesized at relatively high pressure in a laser-heated DAC from amorphous starting material up to 47 and 56 GPa, respectively, at room temperature. The obtained pressure (P)–lattice volume (V) relations show noticeable softening at 22–30 GPa and 35–45 GPa, respectively, which is probably due to the spin transition of Fe. Combining our results and previous reports, we suggest that the lower mantle bdg is capable of containing low-spin Fe3+, which questions the general view. Such a transition changes density and may affect the physical properties of bridgmanite such as thermal conductivity and iron partitioning coefficient, thus having profound implications for mantle dynamics, and the chemical composition of the Earth.

Bridgmanite (Bdg), iron (Fe)- and aluminum (Al)-bearing magnesium silicate perovskite is the most abundant mineral in the Earth's lower mantle. Thus, its thermal conductivity governs the lower mantle thermal conductivity that critically controls the thermo-chemical evolution of both the core and the lower mantle. While there is extensive research for the lattice thermal conductivity of MgSiO3 Bdg, the effects of Fe and Al incorporation on its lattice thermal conduction are still controversial. Here we report the lattice thermal conductivity of Mg0.832Fe0.209Al0.060Si0.916O3 Bdg measured up to 142 GPa at 300 K using the pulsed light heating thermoreflectance technique in a diamond anvil cell. The results show that the lattice thermal conductivity of Bdg is 25.5 ± 2.2 W/m/K at 135 GPa and 300 K, which is 19% lower than that of Fe and Al-free Bdg at identical conditions. Considering the temperature effect on the lattice conductivity and the contribution of radiative thermal conductivity, the total thermal conductivity of Fe and Al-bearing Bdg does not change very much with temperature at 135 GPa, and could be higher than that of post-perovskite with identical chemical composition.

Semiconductor-based heaters for diamond anvil cells (DACs) have advantages over metal wire heaters in terms of repeated use and the ability to reach higher temperatures. We introduce a cylindrical SiC heater for an externally heated DAC (EHDAC) that works satisfactorily at temperatures up to 1500 K and pressures around 90 GPa. The heater is reusable and inexpensive, and only slight modifications to the DAC are required to fit the heater. Experiments on melting of NaCl and gold are conducted at ambient pressure to test the temperature accuracy of the EHDAC system, and resistance measurements on iodine at high pressures and temperatures are performed to assess the heater assembly. These test runs show that a uniform and accurate temperature can be maintained by the EHDAC assembly, which has potential applications to a variety of transport property measurements.

The thermal conductivity of post-perovskite (ppv), the highest-pressure polymorph of MgSiO3 in the Earth's mantle, is one of the most important transport properties for providing better constraints on the temperature profile and dynamics at the core-mantle boundary (CMB). Incorporation of Fe into ppv can affect its conductivity, which has never been experimentally investigated. Here we determined the lattice thermal conductivities of ppv containing 3 mol% and 10 mol% of Fe at high P-T conditions – of pressures up to 149 GPa and 177 GPa, respectively, and temperatures up to 1560 K – by means of the recently developed pulsed light heating thermoreflectance technique combining continuous wave heating lasers. We found that the incorporation of Fe into ppv moderately reduces its lattice thermal conductivity as it increases the Fe content. The bulk conductivity of ppv dominant pyrolite is estimated as 1.5 times higher than that of pyrolite consisting of bridgmanite and ferropericlase in the lower mantle, which agrees with the traditional view that ppv acts as a better heat conductor than bridgmanite in the Earth's lowermost mantle.

We made an active-matrix high-efficiency electron emission device (HEED) that had scanning driver circuits fabricated with conventional MOS planer technology.A 1-in 256x192 pixel image sensor,consisting of the active-matrix HEED and a high-gain avalanche rushing amorphous photoconductor (HARP) target,was fabricated and tested as a step toward the development of ultrahigh-sensitivity compact image sensors with a large number of pixels.The experimental results show that the prototype sensor can be used to obtain clear images even under dark lighting conditions,such as in moonlight,and that the active-matrix HEED is a promising highspeed image pick-up device.

Lotus-type porous magnesium with cylindrical pores aligned unidirectionally was fabricated by the unidirectional solidification of molten magnesium under pressurized hydrogen atmosphere. The apparent attenuation coefficient of the free vibration of lotus-type porous magnesium was measured by hammering–vibration–damping tests, which revealed that the apparent attenuation coefficient increases with increase in porosity, i.e., the damping capacity of lotus magnesium is higher than that of non-porous magnesium. The mechanism of high damping capacity was analyzed by using the Fourier transform technique, which revealed that various vibration modes of high frequency are excited by a hammering. The excited vibrations of high frequency enhance the damping capacity of lotus-type porous magnesium.

Lotus-type porous magnesium with many unidirectional cylindrical pores was fabricated by unidirectional solidification of a melt dissolving hydrogen in a pressurized hydrogen atmosphere. The sound absorption coefficient of porous magnesium whose specimen face has many open pores was measured by the standing-wave method in the sound frequency range up to 4 kHz. The absorption coefficient increases with decreasing pore size, while it increases with porosity. Moreover, the peak value with a high absorption coefficient is shifted toward a higher sound frequency when the thickness of the porous magnesium specimen decreases. It is suggested that lotus-type porous magnesium exhibits excellent sound absorption characteristics.

岩石の弾性的特性を把握する手法として弾性波速度の測定が挙げられ, 近年ではS波による評価も多く実施されている. 本研究では, 岩石供試体の比抵抗に加えてP, S波速度を同時に測定できるシステムの開発を試みた. 弾性波の震源は高周波のインパルスを一方の端面で与え, 他方の端面に受信器を設置し, 伝播した波形を受信した. また, このインパルスは, 繰り返し岩石供試体の一方向に与え, 弾性波は記録した波から速度差とエネルギーの大きさによって, P, S波の初動を読み取った. 同時に岩石供試体の比抵抗はGS式によって測定した. その得られた弾性波速度および比抵抗値と従来の測定法で得られた値を比較した. その結果, 両手法による測定値はよく一致しており, 本測定装置の有効性が認められた.

The guest-emitter doped system has been reported to give a bright electroluminescence (EL). By doping the emitter layer with highly fluorescent dyes, emission colors can be changed and the brightness is also increased. Low work function metals are generally used as a cathode to ensure easier electron injection into organic materials and are expected to reduce driving voltage and increase quantum efficiency for EL devices. We have developed a high luminance dot-matrix display using an organic EL device for the first time.

A flat type image sensor consisting of a field emitter array (FEA) and a high-gain avalanche rushing amorphous photoconductor (HARP)[1] target is developed as the low light imaging compact camera for broadcasting, industry, biology, and so on [2]. In the previous IVNCs, we reported the development of a 1-inch image sensor which consisted of a high-efficiency electron emission device (HEED) [3] with 20 × 20 μm2 pixels [4]. The experiment on the image sensor confirmed an extremely high sensitivity under low-light illumination with a sufficient resolution as expected from the emitter pixel size. For scaling the pixel size further, we developed an active-matrix HEED array with 13.75 × 13.75 μm2 pixels [5]. Fig. 1(a) shows a top-view SEM image of the active-matrix HEED with 13.75 × 13.75 μm2 pixels. For comparison, the image of the previous device is also shown in Fig. 1(b). The improvement in the device isolation method enabled to enlarge the relative emitting area, and then the emission current density per pixel reached 3.6 A/cm2. This highly emissive property fulfilled the imaging requirement of a FEA-HARP image sensor. The device had 640 horizontal and 480 vertical pixels, and the imaging area was 8.8 × 6.6 mm2. The size of this imaging area corresponds to the optical system for the 2/3-inch. The specifications of the active-matrix HEED with 13.75 × 13.75 μm2 pixels, and that of previous one are summarized in Table 1. In this paper, we describe the structure and fundamental characteristics of a prototype 2/3-inch HEED-HARP image sensor.

In this paper, an active-matrix planar-type cold electron emitter array development is studied to fulfill the requirement of high-speed response. This emitter array adopts a novel MIS emitter which is termed HEED (High-efficiency Electron Emission Device) and fabricated on a MOS transistor array formed on a silicon wafer with scan driver circuits. HEED's driving voltage is relatively low (about 20V) and its MIS structure is compatible with silicon planar processing employed for LSI. As a consequence, The HEED is one of the most suitable emitters for an active-matrix drive configuration. The emission current density (defined as the average pixel current per emitter area size) reaches up to 4.4 A/cm . This highly emissive property fulfills the imaging requirement of a HARP target. The specifications of the active-matrix HEED are summarized. The number of the interconnections to drive this chip is applicatory 12 lines. This is another important advantage of the active-matrix drive method.

A 256 /spl times/ 192 pixels active-matrix cold electron emitter array with integrated scan driver circuits is developed. The basic structure of the electron emitter is almost the same as that of an advanced HEED (high-efficiency electron emission device) previously reported. The emission current density of the active-matrix HEED has been enhanced more than 100 times compared to that of the advanced HEED under the passive operation mode. It is demonstrated that the developed emitter can be applied to flat image sensing with a high-gain avalanche rushing amorphous photoconductor (HARP) target.

An image sensor consisting of an active-matrix high-efficiency electron emission device (HEED) array and a high-gain avalanche rushing amorphous photoconductor (HARP) has been fabricated. Based on the demonstration that a prototyped 256×192pixel image sensor can pick up a high definition image with an ultrahigh sensitivity under poor light condition, the authors have been developing a 640×480pixel active-matrix HEED toward a practical use. The emission current density has been enhanced more than twice compared to that of previous one and has increased up to 1A∕cm2. The active-matrix HEED array combined with HARP is available for application to practical image sensing with an ultrahigh sensitivity and high definition.

For practical advantages of the HEED (high-efficiency electron emission device) such as a low driving voltage, a high emission current density, especially application to an ultra high sensitive compact image sensor can be expected. A prototype active-matrix HEED image sensor integrated with scanning driver circuits was developed with a HARP (high-gain avalanche rushing amorphous photoconductor) target. It was demonstrated that the prototype 256 times 192 pixels active-matrix HEED array operates well as an effective probe for high-resolution image pickup under dim lighting. The possibility of the active-matrix HEED for development of next-generation image sensor with ultra high sensitivity and high definition was concluded in this report

We recently developed a new-type cold cathode termed HEED (High-Efficiency Electron-emission Device) based on the Metal-Insulator-Semiconductor (MIS) diode. It has been shown that by arranging the device and surface structures the emission characteristics can be significantly improved. Using the advanced HEED as an excitation source, a 4-inch prototype flat panel display has been fabricated on a glass substrate. The panel operates well with a practical brightness at a relatively low driving voltage. The occasional reactivation technique is very effective to prolong the operation life of this device.

A 640×480pixel image sensor has been developed for low light imaging with a practical resolution. This image sensor combined an active-matrix high-efficiency electron emission device (HEED) with a high-gain avalanche rushing amorphous photoconductor (HARP) target. To meet the requirement for a scaling of the imaging size, we developed a 2∕3in. image sensor based on an active-matrix HEED with 13.75×13.75μm2pixels. The highly emissive property of 3.8μA∕pixel was comparable to that obtained previously from a 1in. device. The possible effect of the pixel size scaling on the image-pickup sensitivity was compensated by a significant increase in the emission current density. The technological potential of the HEED-HARP image sensing has been further enhanced toward practical use.

An active-matrix array of high-efficiency electron emission device (HEED) with a sufficient output density has been developed for the use as imaging probe in a high-gain avalanche rushing amorphous photoconductor target. Previously, it was demonstrated that a prototyped image sensor with 20×20μm2pixels could pick up a high definition image with an ultrahigh sensitivity under low-light-level condition. Based on it, an efficient active-matrix HEED with 13.75×13.75μm2pixels is fabricated for pursuing higher sensitivity and resolution. The improvement in the device isolation method enables to enlarge the relative emitting area, and then the emission current density per pixel reaches 3.6A∕cm2 that is about four times of that obtained from the previous one. The active-matrix HEED array with small pixels is available for application to the compact ultrahigh-sensitivity image sensor without affecting on the image definition.

An extremely high-sensitivity image sensor has been developed with a combination of an active-matrix high-efficiency electron emission device (HEED) array and a high-gain avalanche rushing amorphous photoconductor (HARP) target. Following the description of the requirements for the use of the electron emitter as an image-sensing probe, the characteristics of a fabricated 640×480 pixel active-matrix HEED image sensor with a HARP target are presented by image-pickup experiments under a dark condition. The emission current density of the experimental HEED under an active-matrix drive was 4 A/cm2 corresponding to a practical level. A clear image observed in the prototype compact camera demonstrates that the surface-emitting HEED is useful for image sensing based on HARP with high sensitivity and sufficient definition.

Practical advantages of an advanced high-efficiency electron emission device (HEED) (low-voltage operation, relatively simple structure, and availability for large-area applications) are further confirmed by its compatibility with active-matrix drive configuration. The fabricated HEED array has been applied to a high-sensitivity image sensing tube with a target of high-gain avalanche rushing amorphous photoconductor (HARP). It is demonstrated that a prototype 256×192pixel active-matrix HEED array operates well as an effective probe for high-resolution image pickup in combination with a HARP target. The advanced HEED array is promising for development of next-generation image sensor with ultrahigh sensitivity and high definition.

We developed an active matrix driving organic light-emitting diode (OLED) panel on a glass substrate using two organic thin-film transistors (OTFTs) per pixel, a switching OTFT and a driving OTFT. The OTFTs are bottom contact structures with the high-dielectric constant gate insulator tantalum oxide (Ta2O5, relative dielectric constant of 23) produced by anodization in ammonium adipate solution and with pentacene as the active layer. The W/L (where W and L are the OTFTs channel width and length, respectively) was 400 µm/10 µm for the switching OTFTs and 680 µm/10 µm for the driving OTFTs. The characteristics of the OTFTs were improved by treating the Ta2O5 surface with hexamethyldisilazane (HMDS), so that the field-effect mobility was 2.0×10-1 cm2 V-1 s-1 and the current on/off ratio was 105. A green phosphorescent dopant, tris(2-phenylpyridine)iridium [Ir(ppy)3], was used for the OLED layer. The panel had 8×8 pixels and the aperture ratio was 27%. We confirmed a 16-gray-scale representation and a luminance of 400 cd/m2.

As previously reported, the emission characteristics of metal-insulator-semiconductor (MIS) electron emission devices could be significantly improved by introducing microdimple structures into the emission sites. In this paper, we describe the characteristics of efficient cold electron emitters from a viewpoint of application to flat panel display (FPD). First, the forming operation for the device to activate the dynamic emission is discussed on a basis of the experimental analyses of the electrical properties and output electron energy spectra. Next it is demonstrated that the device has some desirable features as an excitation source of FPD: a high emission current density, a low operation voltage, emission uniformity, and stable emission with small angle dispersion. It is also shown from the result of lifetime evaluation that the device shows a half-life of 3000 h, and that the deteriorated emission can be recovered by the dc reactivation treatment.

By using organic thin-film transistors with pentacene as the active organic layer, active matrix organic light emitting diode panel has been developed. The number of pixels in the panel is 8 × 8, and each pixel is driven by switching and driving transistors. We confirmed 16 gray scales representation by means of an analog driving method.

3-endo-Benzamido-5-norbornene-2-endo-carboxylic acid was synthesized from 5-norbornene-2-endo,3-endo-dicarboxylic anhydride in one pot and easily resolved into a pair of optically active forms by p...

3-endo-Benzamido-5-norbornene-2-endo-carboxylic acid was synthesized from 5-norbornene-2-endo,3-endo-dicarboxylic anhydride in one pot and easily resolved into a pair of optically active forms by p...