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We present the design and fabrication of a 2D monolithic pixelated detector array using metalorganic vapor-phase epitaxy grown thick CdTe epitaxial layers on Si substrates. Each pixel in the array consists of a p-CdTe/n-CdTe/n+-Si heterojunction diode structure, and pixels were patterned by cutting deep vertical grooves using a dicing saw. We also developed a low-temperature conductive-epoxy based bonding technique to bond the array to the read out electronic circuit via an interface board. Preliminary evaluation shows that the fabricated array is capable of discriminating energies of the incident radiation and can be applied for the energy discriminating imaging purpose. Moreover, this fabrication technique is useful in developing larger imaging arrays.

We present reverse bias current (dark current) characteristics of a two-dimensional monolithic pixel-type nuclear radiation detector array fabricated using metalorganic vapor-phase epitaxy (MOVPE)-grown thick CdTe epitaxial layers on Si substrate. The (14 × 8) pixel array was formed by cutting deep vertical trenches using a dicing saw, where each pixel possesses a p-CdTe/ n-CdTe/n+-Si heterojunction diode structure. The dark currents showed pixel-to-pixel variations when measured at higher applied biases exceeding 100 V. The dark current had a dependence on the pixel thickness, where pixels with lower CdTe thickness exhibited higher currents. Moreover, the temperature dependence of the dark current revealed that a deep level with activation energy of around 0.6 eV is responsible for the observed dark currents and their pixel-to-pixel variation. We discuss that the effective ratio of Te to Cd at the growth surface is a major factor that controls the thickness variation, and is also responsible for the formation of 0.6 eV deep levels.

We present fabrication process of two-dimensional (2D) energy discriminating pixel-type imaging arrays. Each pixel in the array possesses a p-CdTe/n-CdTe/n+-Si heterojunction diode structure. The array is fabricated using metalorganic vapour-phase epitaxy grown thick layers of single crystal CdTe on (211)Si substrates. In order to avoid the charge sharing problem among the adjacent pixels, we used a mechanical saw based pixel pattering technique, which produced pixels that are isolated from each other by narrow vertical trenches. Preliminary evaluation with room-temperature reverse biased dark current values exhibited uniform response from the entire pixels in the array. This opens a new possibility for developing large-area imaging arrays in a simple and efficient way. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Wavelength modulation over 500 kHz by a micromechanically tunable vertical-cavity surface-emitting laser (VCSEL) consisting of an InP-based half-VCSEL chip and a micromachined silicon-on-insulator chip with a concave movable mirror has been demonstrated for the first time. A peak power of 3.5 mW, a tuning range of 55 nm, and a side-mode suppression ratio of about 60 dB have been demonstrated.

Eight asthmatic patients with hard metal asthma due to cobalt underwent bronchial provocation challenge with nickel sulphate. Seven patients developed a fall in FEV1 of 20% or more after inhaling nickel sulphate, four showing an immediate response and three a late response. Eight control subjects, including six asthmatic patients, with no history of hard metal exposure, showed no bronchoconstriction in response to a provocation challenge with nickel sulphate. Specific antibodies to nickel conjugated human serum albumin were present in four of the eight patients with sensitivity to cobalt conjugated human serum albumin but were absent from the serum of 60 unexposed asthmatic patients and 25 exposed symptom free workers. These results suggest that nickel as well as cobalt sensitivity plays a part in hard metal asthma.

We propose a novel speech processing framework, where all of the speech data are encoded into universal phonetic code (UPC) sequences and speech processing systems, such as speech recognition, retrieval, digesting, etc., are constructed on this UPC domain. As the first step, we introduce a sub-phonetic segment (SPS) set, based on IPA (international phonetic alphabet), to deal with multilingual speech and develop a procedure to estimate acoustic models of the SPS from IPA-like phone models. The key point of the framework is to employ environment adaptation into the SPS encoding stage. This makes it possible to normalize acoustic variations and extract the language factor contained in speech signals as encoded SPS sequences. We confirm these characteristics by constructing a speech retrieval system on the SPS domain. The system can retrieve key phrases, given by speech, from different environment speech data in a vocabulary-free condition. We show several preliminary experimental results on this system, using Japanese and English sentence speech sets.

This paper proposes a novel speech processing framework, where all of the speech data are once encoded into universal phonetic code (UPC) sequences and speech processing systems, such as speech recognition, retrieval, digesting, are constructed on this UPC domain. First of all, we introduce an IPA-based sub-phonetic segment (SPS) set as the UPC to deal with multilingual speech. In the UPC (SPS) domain, each UPC accompanies a reference acoustic model which is independent of real acoustic models used in the encoding process. Processing, such as recognition, in the UPC domain is conducted based on the distance between UPC sequences estimated by using the reference acoustic models. We confirm the proposed framework by constructing a speech recognition and a vocabulary-free speech retrieval system on the SPS domain. We show several experimental results on these systems, using Japanese and English speech data sets.

The memory retention properties of Pt/YMnO3/Y2O3/Si capacitors were investigated for the application of ferroelectric gate transistors. The epitaxially grown Pt/YMnO3/Y2O3/Si capacitors showed ferroelectric type hysteresis loop on the capacitance-voltage properties. Although the retention time of the as-deposited capacitors was ∼103 s, it was prolonged up to 104 s when the leakage current density was reduced from 4×10−8 A/cm2 to 2×10−9 A/cm2 by the annealing under N2 ambience. To reveal the relationship between the retention time and leakage current, the leakage current mechanism was investigated comparing several conduction mechanisms. It was found that the dominant leakage mechanisms at high and low electric fields were Poole-Frenkel emission from the Y2O3 layer and ohmic conduction, respectively. This result indicates that the leakage current was limited by the Y2O3 layer at high electric field and was mainly dominated by the amount of defects in the YMnO3 layer at low electric field. From the pseudo isothermal capacitance transient spectroscopy (ICTS), it was determined that the trap density was in an order of 1015 cm−3. Since the variation of the leakage current by annealing was observed only in the low electric field region, it is suggested that the retention properties of the Pt/YMnO3/Y2O3/Si capacitors was influenced by the amount of defects in the YMnO3 layer.

We have much difficulty in developing good software efficiently for embedded microprocessors (MPs) because of insufficient requirements analysis and incomplete product specification. To improve the situation, we often consider adopting an upper CASE tool. However, it is not clear that an upper CASE tool is effective in developing software for embedded MPs. We researched the software development environments and the use of upper CASE tools in Japan and the USA. As a result, we found differences in the software development environments of the two countries, and particularly we found differences in the use, effects and evaluation of upper CASE tools. It seems that Japanese vendors have not used upper CASE tools in an expedient way yet. >

In order to design or construct underground structures such as tunnels or caves, it is required to estimate accurately the foundation structure. In general, such estimation is carried out by digging bore holes and/or various experiments using the data thus obtained. However, even through such a procedure, we can estimate only point-wisely the foundation structure, although the total feature of the foundation is required.

The authors have investigated the electron transport properties of Zn1−xMnxO∕ZnO modulation-doped heterostructures grown on ZnO (0001¯) single-crystal substrates. By varying the growth temperature (Tg) of ZnO and Zn1−xMnxO layers, the growth mode changes from three-dimensional grain growth to two-dimensional growth. In this study, Zn0.88Mn0.12O∕ZnO heterostructures with different growth modes of the Zn0.88Mn0.12O barrier layer were fabricated by deposition at different Tg. The effect of the growth mode of the Zn0.88Mn0.12O barrier layer on carrier confinement at the Zn0.88Mn0.12O∕ZnO heterointerface is discussed.

Rigid fixation with plates or screws has been widely favored following sagittal split ramus osteotomy of the mandible. Its advantages include early recovery of jaw function, rapid bone healing, and decreased potential for relapse. However, when improper positioning of the proximal segment occurs during the fixation procedure, various problems can result, including limitation of mouth opening, pain and/or clicking in the temporomandibular joint, and skeletal relapse. To avoid these problems, a number of methods have been proposed to maintain the original position of the proximal segment. These methods are based on the use of a standard point that does not change before and after splitting of the mandible. For this point, the zygoma’.’ or maxillary teeth3-6 are usually chosen. The advantage of choosing the zygoma as a standard point is that it is available even in two-jaw surgery. The disadvantage is that adjustment of a miniplate extending from the zygoma to the proximal segment is time consuming3 because of the complicated contour of the zygoma and ramus. Alternatively, choice of the maxillary teeth as a standard point has the disadvantage of being fairly unstable, and the procedure can affect the orthodontic appliance. We have, therefore, developed a new appliance that uses the alveolus and teeth as the standard point.

As Zinc oxide films have many available characteristics, a large number of crystallographic studies have been reported on the films deposited by sputtering. However, most of those are about the influence of deposition conditions for (002) (c-axis) oriented films(l)–(2). The growing process of ZnOx films has not been necessarily manifested.

Progress in patterning technologies and computer‐aided circuit designs have brought us to the threshold of submicron dimensions in the fabrication of very large scale integrated circuits. For metallization at submicron dimensions, several requirements must be satisfied. In the present study we have prepared pure Al and Al–Y alloy films with different yttrium concentration by electron‐beam evaporation and evaluated several annealing characteristics for the Al–Y/(100)Si system by using a transmission electron microscope, scanning electron microscope, and measuring the electrical resistivity. We found that in the Al–0.7 wt % (0.2 at. %) Y alloy film annealed above 300 °C the electrical resistivity decreases to a value similar to that of a pure Al film, that is, 2.9 μΩ cm, and the same concentration of yttrium is also sufficient to minimize the generation and growth of annealing hillocks. These results are explained by the compositional and microstructural changes occurring in the Al–Y/(100)Si system.

This paper briefly reviews the materials used in LED manufacture and describes types and applications of simple LED displays. A three-colour 16 × 16 element display module is introduced. By using metallic ribbons to wire the elements on the display side in place of wire bonding, it is expected that the modules will be more easily mass-producible.