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101.
Photoconductivity gain (PG) and persistent photoconductivity (PPC) properties observed in diamond photodetector are theoretically explained by solving rate equations which describe capture and emission processes of photo-generated hole and electron through a boron acceptor and a hole trap in a diamond epilayer and a nitrogen donor in a diamond substrate. Formation of one-sided pn-junction between the epilayer and substrate and slow hole capture rate of acceptor and hole trap levels provide accumulation of photo-generated hole in the epilayer, which produces the PG larger than the ideal responsivity. The PPC current after turning off the deep ultraviolet light is interpreted as due to the slow hole capture rate of the acceptor and trap levels. 相似文献
102.
Chisato Takahashi Deepak K. Pattanayak Takashi Shirai Masayoshi Fuji 《Journal of the European Ceramic Society》2013,33(4):629-635
The purpose of this study is to develop a simple method to observe the surface morphology of non-conductive material in its hydrated condition. Here porous hydroxyapatite (HAp) green body prepared by gelcasting process was considered as a case study, and, the resultant body was subsequently treated with hydrophilic ionic liquid (IL). The surface morphology and the pore structure of the IL-treated porous HAp green body were successfully observed even in hydrated condition without any charging using field emission scanning electron microscope (FE-SEM). Results showed that the pore diameter from 300 to 600 μm in as-prepared green body was reduced to 100–300 μm in the sample sintered at 1000 °C. Raman results showed that the IL forms weak hydrogen bond with water molecules within the sample and, that prevents from drying in vacuum condition. In addition, the IL acts as a conducting media for HAp ceramics to be observed under FE-SEM. 相似文献
103.
The concrete modular dry storage technologies are becoming widely used, aiming at better economic performances. With longer perspective, there are still key issues related to safety standards in operation and maintenance during storage and unloading/loading for transportation, long-term integrity of the storage components. On the other hands, due to the lack of the experimental studies related to tipping-over or drop event scenarios, it is very important to evaluate the characteristics of the behavior of the components, such as the multi-purpose canister (MPC) subjected to impact loads. Therefore, we executed the demonstration drop test program using double-lid welded MPCs, with the aim of obtaining basic data for regulating safety. This paper introduces the summary of our drop test program. 相似文献
104.
Several fracture forces for the evaluation of the forming limit are investigated. The influence of flange lubrication, blank shapes, blank materials and tool shapes on the fracture forces is examined. The increase in the critical fracture force (the ability to sustain deep-drawing forces) is required for the improvement in the deep-drawability of square cups. Constant fracture force and transitional fracture force are used as target values for the increase in the critical fracture force. Both the fracture forces are independent of the blank shapes, and influenced by the flange lubrication, the blank materials and the tool shapes. The deep-drawability of square cups is evaluated by means of the fracture forces. 相似文献
105.
Eduardo Jacob-Lopes Sergio Revah Sergio Hernndez Keiko Shirai Telma Teixeira Franco 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2009,153(1-3):120-126
The objective of this work was to evaluate different operational strategies for photobioreactors to remove carbon dioxide using the cyanobacteria, Aphanothece microscopica Nägeli. Two types of reactor configuration, bubble column and airlift were evaluated under three different operational conditions to treat air containing 15% carbon dioxide: simple operation, air recirculation and two sequential reactors. The results obtained showed that the reactor configuration and the operational mode were both determinant criteria for the performance of photobioreactors in the biological conversion of carbon dioxide. Operations with air recirculation showed possibilities for use in small-scale operations, but two-stage sequential photobioreactors (elimination capacity and removal efficiency of 12,217 gcarbon/m3reactor day and 52.5%, respectively) were shown to be the operational mode with greatest potential for application on an industrial scale by the increased removal efficiency. 相似文献
106.
107.
Source-Field Relationships for Cardiac Generators on the Heart Surface Based on Their Transfer Coefficients 总被引:1,自引:0,他引:1
We consider three different types of equivalent sources over a closed surface enclosing all the electrical cardiac generators: the (in situ) potential, the (in situ) normal current density, and the (macroscopic) transmembrane potential on the heart surface. The last equivalent source, which behaves as a double layer, is derived from the bidomain (bisyncytia) model for anisotropic cardiac muscle. This model predicts that if ratios of intracellular to interstitial conductivity along all directions are equal, field potential can be calculated only using surface integrals. The volume integral arising from the tissue anisotropy of cardiac muscle vanishes in that case. For each type of source under study, we give the field potential in a bounded inhomogeneous volume conductor in the form of an integral equation. We also derive the conditions which the lead field (or the transfer coefficients) must satisfy. The in situ potential and normal current are related to the cardiac sources in a complex way, but their lead fields are independent of conductivity of heart muscle, whereas the transmembrane potential is directly involved as a source term, but the lead field depends on the anisotropy of the heart muscle. 相似文献
108.
109.
Hiroyuki Mishima Mituo Kakei Toshio Yasui Saori Miyamoto Yasuo Miake Takaaki Yanagisawa 《Frontiers of Materials Science in China》2008,2(2):179-181
The present study was aimed at examining the nature of apatite crystal in the tooth apparatus of a conodont fossil using transmission
electron microscopy (TEM), scanning electron microscopy (SEM), laser Raman microprobe spectrometry and electron-probe microanalysis
(EPMA). The hard tissue of the condont consisted of 2 layers and the organization varied with the size of the crystal. Higher
magnification showed that the crystals were observed in the lattice of (100) and the central dark lines were not present.
Ca, P, and F were detected in the crystal using EPMA. Our results indicate that the apatite crystal in conodont fossils is
not hydroxyapatite but fluorapatite. 相似文献
110.
Yasuo Cho Teruaki Kasahara Koichi Fukuda 《Journal of the American Ceramic Society》1999,82(7):1720-1724
Two-dimensional images of the distribution showing the temperature coefficient of the dielectric constant for two types of two-phase composite ceramics composed of TiO2 -Bi2 Ti4 O11 and BaTi4 O9 -BaPr2 Ti4 O12 were obtained using scanning photothermal dielectric microscopy. The images of the TiO2 -Bi2 Ti4 O11 ceramic showed that the TiO2 and Bi2 Ti4 O11 grains had negative and positive temperature coefficients, respectively, and that the macroscopic averaged temperature coefficient of the ceramic was relatively low because of the cancellation of the opposite signs of the coefficients. On the other hand, the images of the BaTi4 O9 -BaPr2 Ti4 O12 ceramic showed that the temperature coefficient of both grains had the same sign (negative), although their absolute values were quite different. 相似文献