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排序方式: 共有1903条查询结果,搜索用时 15 毫秒
101.
Wei Zhou Chak Wah Tang Jia Zhu Kei May Lau Zeng Y. Liu H.G. Tao N.G. Bolognesi C.R. 《Electron Device Letters, IEEE》2007,28(7):539-542
Good-quality metamorphic InP buffer layers have been successfully grown on GaAs substrates by metal-organic chemical vapor deposition. Characterization by atomic force microscope, transmission electron microscopy, high-resolution X-ray diffraction, and Hall measurements indicated that the layers are of high crystalline quality, good mobility, and excellent surface morphology. On this buffer, we demonstrated the first metamorphic InP/GaAsSb/InP double heterojunction bipolar transistors (DHBTs) with good material quality and device performance. Metamorphic DHBTs showed direct-current and radio-frequency characteristics that are comparable to those grown on lattice-matched InP substrates. 相似文献
102.
In this work, a detailed TEM sample preparation recipe based on a wedge polishing technique for GaN-based materials is presented. The obtained samples have atomically flat surfaces without any obvious surface damages such as the formation of amorphous layers. A composition estimation of Al(x)Ga(1-x)N from Z-contrast STEM imaging is carried out using these samples. The results are in good accord with the nominal composition. 相似文献
103.
Recovering high dynamic range by Multi-Exposure Retinex 总被引:1,自引:0,他引:1
Feng Shen Yuming Zhao Xingzhi Jiang Masaki Suwa 《Journal of Visual Communication and Image Representation》2009,20(8):521-531
The matter of generating high dynamic range (HDR) image from a number of differently exposed pictures arises to satisfy the needs of high-quality imaging and industrial applications. A number of HDR image generation algorithms have been proposed in the past. However, the HDR radiance map recovered by these classical methods cannot completely exclude the noisy pixels in the input images and thus are unable to produce the optimal result with highest possible SNR. In this paper we are going to introduce a new HDR generation algorithm based on the Multi-Exposure Retinex model deduced in this paper for HDR image composition. The luminance component L and the reflectance R are synthesized independently before being combined together. A novel R image composition method is introduced to help the composed result image reach the highest possible SNR. The method is tested on grey-level images in this paper, but it can be easily extended to the color-image version. 相似文献
104.
Kazuhisa Okamoto Mai Ohta Kei Inage Takeo Fujii Masayuki Ariyoshi 《Analog Integrated Circuits and Signal Processing》2012,73(2):503-516
Because of the rapid development of cognitive radio technologies, research on sharing frequency resources allocated to primary users with secondary users has attracted much attention. If a frequency band is unused by the primary users, multiple secondary users are expected to share the spectrum in a future wireless communication network. To efficiently share the spectrum among secondary systems, we propose a novel channel allocation method that uses a frequency priority table generated based on the location of the secondary system. By using this method, the interference with other systems is autonomously reduced by selecting channels. Moreover, a power control method is also proposed for protecting the secondary systems that are allocated to the channels with higher priority. 相似文献
105.
106.
日本では,21世紀半ばに人工の固体物質の代表である解体コンクリート塊の排出量がピークを迎えると同時に,最終処分が困難になる状況が想定されていることから,コンクリート材料の完全資源型の利活用要求はより一層高まるといえる.本研究は,副産微粉,再生骨材などの二次副産材を積極的に混和し,同一産地*種類型の調合条件のもとで,コンクリートの物性改善,資源有効利活用を目的としたコンクリートを製造し,その基礎的物性の評価と環境影響評価を行い,環境保全に資するコンクリート材料の発展的利用のあり方を検討した. 相似文献
107.
Kaoru Abe Yasuhiro Sakurai Akira Okuyama Kazuhiro Sasaki Kei Tawarada 《Journal of the science of food and agriculture》2009,89(6):1097-1100
BACKGROUND: The behavior of cadmium in ecosystems needs to be monitored because of the human toxicity of this heavy metal. The need recently arose for a simple and quick on‐site test for trace levels of Cd in food and environmental samples. In response, an immunochromatographic assay kit for detecting Cd was manufactured by Kansai Electric Power Co. of Japan. This kit uses the antigen–antibody complex reaction between the Cd–EDTA complex and an anti‐Cd–EDTA antibody and shows the results in terms of the degree of color developed on a test paper. We previously reported the successful use of this kit to determine Cd concentrations in brown rice. Here, we applied the kit to the determination of Cd concentrations in rice foliage and soil. RESULTS: Cadmium in rice foliage was not extracted successfully by the method used for brown rice. However, it was successfully extracted by 0.1 mol L?1 HCl solution at a rice foliage:HCl ratio of 1:20, and coexisting metals were removed sufficiently by the column treatment. The Cd concentrations determined by immunochromatographic assay were well correlated with the values obtained by acid decomposition and inductively coupled plasma mass spectrometry. The 0.1 mol L?1 HCl‐extractable Cd concentration in soil was also determined successfully with the kit. CONCLUSION: Approximate Cd concentrations in rice plants and 0.1 mol L?1 HCl‐extractable Cd concentrations in soil can be monitored easily and quickly by this method at locations where facilities for acid digestion and precision analysis are not available. Copyright © 2009 Society of Chemical Industry 相似文献
108.
In this paper a pen-based intuitive interface is presented, that controls a virtual human figure interactively. Recent commercial pen devices can detect not only the pen positions but also the pressure and tilt of the pen. We utilize such information to make a human figure perform various types of motions in response to the pen movements manipulated by the user. The figure walks, runs, turns and steps along the trajectory and speed of the pen. The figure also bends, stretches and tilts in response to the tilt of the pen. Moreover, it ducks and jumps in response to the pen pressure. Using our interface, the user controls a virtual human figure intuitively as if he or she were holding a virtual puppet and playing with it.
In addition to the interface design and implementation, this paper describes a motion generation engine to produce various motion based on varying parameters that are given by the pen interface. We take a motion blending approach and construct motion blending modules with a set of small number of motion capture data for each type of motions. Finally, we present the results from user experiments and comparison with a transitional gamepad-based interface. 相似文献
109.
110.
Shimizu T Miyahayashi Y Yokoo M Hoshino Y Sasada H Sato E 《Reproduction (Cambridge, England)》2004,128(5):537-543
Growth differentiation factor-9 (GDF-9) is a growth factor secreted by oocytes in growing ovarian follicles. To investigate the ovarian function of GDF-9 in pigs, we first cloned porcine GDF-9 complementary DNA (cDNA), and then injected its gene fragments into the ovary in gilts. Porcine GDF-9 has open reading frame (ORF) homologies of 81.4%, 84.6%, 84.2%, 72.7% and 72.6% with its human, bovine, ovine, rat and mouse counterparts respectively. Regarding the deduced amino-acid sequence of the mature protein, the corresponding homologies reach 92.1%, 97.8%, 97.0%, 89.6% and 88.1% respectively. To investigate the role of GDF-9 in early folliculogenesis, the ovaries of 2-month-old prepubertal gilts were injected with GDF-9 gene fragments. The injection of porcine GDF-9 gene fragments resulted in an increase in the number of primary, secondary and tertiary follicles, concomitant with a decrease in the number of primordial follicles. These results indicated that exogenous GDF-9 can promote early folliculogenesis in the porcine ovary, and that a technique for direct ovarian injection of GFD-9 gene fragments may contribute to a novel therapy for prevention and treatment of infertility associated with ovarian dysfunction. 相似文献