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41.
An integrated fiber-optic probe comprising a short length of multimode fiber that is fusion spliced to a monomode optical fiber has been fabricated for imaging and nonimaging applications. The fiber probe, typically 250 μm in diameter, can deliver a focused Gaussian spot approximately 25 μm in diameter at a distance of approximately 500 μm from the tip. Two off-the-shelf graded-index multimode fibers have been used in the fabrication of imaging and nonimaging probes. These integrated probes have considerably improved the spatial resolution of backscatter lensless fiber probes being utilized in the dynamic light-scattering characterization of colloidal suspension. 相似文献
42.
Ferroelectrically Gated Atomically Thin Transition‐Metal Dichalcogenides as Nonvolatile Memory 下载免费PDF全文
43.
44.
Sunghak Lee Dongwoo Suh Dongil Kwon 《Metallurgical and Materials Transactions A》1996,27(12):3893-3901
A microstructural analysis of local microfracture of cast A356 Al-SiC
p
composites fabricated by permanent mold re-casting and squeeze-casting methods was made. Notch fracture toughness tests were
conducted on these composites to identify critical fracture parameters using a stress-modified critical-strain criterion.
The composite microstructure shows continuous networks of densely populated SiC and eutectic Si particles along the intercellular
regions. Squeeze casting produces a more homogeneous structure and larger spacing of brittle particles and increases the tensile
ductility and fracture toughness, while strength levels are almost identical to the re-casting case. The calculated values
of the microstructurally characteristic distancel* for the re-cast and squeeze-cast composites are about 40 μm, which is comparable to the average sizes of the intercellular
network. However, the reference critical strain
for squeeze casting is larger than that for re-casting, showing a trend to higher ductility and fracture toughness. 相似文献
45.
Woo Young Kwon Il Hong Suh Sanghoon Lee 《International Journal of Control, Automation and Systems》2011,9(2):328-338
Reinforcement learning (RL) has been widely used as a mechanism for autonomous robots to learn state-action pairs by interacting
with their environment. However, most RL methods usually suffer from slow convergence when deriving an optimum policy in practical
applications. To solve this problem, a stochastic shortest path-based Q-learning (SSPQL) is proposed, combining a stochastic
shortest path-finding method with Q-learning, a well-known model-free RL method. The rationale is, if a robot has an internal
state-transition model which is incrementally learnt, then the robot can infer the local optimum policy by using a stochastic
shortest path-finding method. By increasing state-action pair values comprising of these local optimum policies, a robot can
then reach a goal quickly and as a result, this process can enhance convergence speed. To demonstrate the validity of this
proposed learning approach, several experimental results are presented in this paper. 相似文献
46.
This study investigated the effectiveness of massive multiplayer online role‐playing game (MMORPG)‐based (massive multiplayer online role‐playing game) instruction in elementary English education. The effectiveness of the MMORPG program was compared with face‐to‐face instruction and the independent variables (gender, prior knowledge, motivation for learning, self‐directed learning skills, computer skills, game skills, computer capacity, network speed, and computer accessibility) were examined to see how accurately achievement was predicted in MMORPG instruction. The results indicated that students studying English utilizing online role‐playing games showed higher scores in areas of listening, reading, and writing than those who attended face‐to‐face instruction classes. It was also found that prior knowledge, motivation for learning, and network speed were factors affecting achievement in English learning. These findings suggest that MMORPGs can play an important role in improving English communicative skills. 相似文献
47.
Sung Wook Kim Hyoung Sun Yoo Byoung‐Hwa Kwon Dong Seok Kang Minwon Suh Duk Young Jeon 《Journal of the Society for Information Display》2010,18(12):1104-1110
Abstract— In this study, organic wavelength‐converting films (WCFs) applied to InGaN blue LED‐based hybrid planar WLED has been fabricated. The organic dye layer in the WCF was formed between the upper and bottom polymer sheets by using a simple roll‐laminating technique. Subsequently, the hybrid planar WLEDs have been fabricated based upon these films. The luminous efficiency of green WCF‐based hybrid planar WLEDs with a single blue LED chip was 34.6 lm/W and that of red‐WCF‐assisted green WCF‐based hybrid planar WLEDs was 27.3 lm/W under 20 mA. The use of WCF to fabricate hybrid planar WLEDs showed better stability than that of directly coating organic color‐convergence materials (CCMs) on the LED chips. It only decreased to about 10% of the initial wavelength‐converting intensity after 1 hour of continual operation at 20 mA. 相似文献
48.
Tae-Il Suh Eui-Jin Kim Bum-Jik Lee Jon-Ha Ryu Sung-Eun Lee 《International Journal of Control, Automation and Systems》2010,8(2):454-461
This article describes the performance comparison of several tracking filters from the viewpoint of gun fire control. It is common that filter performance can be represented by the RMSE of the current state. However, for the design of a gun fire control system, the performance of the tracking filter in terms of prediction is more important since the current state proceeds with a designed dynamic model to a certain future which is used for the final gun order. It is shown that the predicted results amplify the current state RMSE and can be a good measure. 相似文献
49.
A strategy for a knowledge-based system to detect the interior and exterior boundaries of the left ventricle from time-varying cross-sectional images obtained by ECG-gated magnetic resonance imaging (MRI) is discussed. The system uses both fuzzy set theory and Dempster and Shafer theory to manage the knowledge and to control the flow of system information for more efficient use of limited computational resources and memory space. The key to the approach is that it performs edge detection on images through integration and unification of knowledge and information from edge candidates on all the slices and phases of the acquired cardiac MRI dataset. The analysis system does not base decisions on individual measurements, but on consensus opinions by combining many knowledge sources, some of which may not be completely accurate. 相似文献
50.
Dong-Woo Suh Chang-Seok Oh Sung-Joon Kim 《Metallurgical and Materials Transactions A》2005,36(4):1057-1059
High-angle grain-boundary spacing in deformed austenite is analyzed using Ni-30Fe alloy to explain the change of ferrite grain
size by severe plastic deformation (SPD) of austenite in low carbon steel. It is suggested that constant high-angle grain-boundary
spacing in deformed austenite resulting from dynamic recrystallization (DRX) or geometric DRX is responsible for the limit
of ferrite grain refinement over a certain level of plastic deformation of austenite. 相似文献