Browsing by Author "Chen, H. H."

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Imaging cells and sub-cellular structures with ultrahigh resolution full-field X-ray microscopy
(2013-05-01)
Chien, C. C.
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Tseng, P. Y.
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Chen, H. H.
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Hua, T. E.
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Chen, S. T.
Our experimental results demonstrate that full-field hard-X-ray microscopy is finally able to investigate the internal structure of cells in tissues. This result was made possible by three main factors: the use of a coherent (synchrotron) source of X-rays, the exploitation of contrast mechanisms based on the real part of the refractive index and the magnification provided by high-resolution Fresnel zone-plate objectives. We specifically obtained high-quality microradiographs of human and mouse cells with 29 nm Rayleigh spatial resolution and verified that tomographic reconstruction could be implemented with a final resolution level suitable for subcellular features. We also demonstrated that a phase retrieval method based on a wave propagation algorithm could yield good subcellular images starting from a series of defocused microradiographs. The concluding discussion compares cellular and subcellular hard-X-ray microradiology with other techniques and evaluates its potential impact on biomedical research. (C) 2012 Elsevier Inc. All rights reserved.
The investigation of charge loss mechanism in a two-bit wrapped-gate nitride storage nonvolatile memory
(2010-11-01)
Ho, Y. H.
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Chung, Steve S.
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Chen, H. H.
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
The charge loss mechanism of a two-bit wrapped-gate nitride storage nonvolatile memory is investigated. From retention measurements, it was shown that both vertical and lateral charge loss coexist. As a result of the misalignment of carriers, the lateral charge loss was caused by the hole accumulation near the junction and migrating toward the channel. By using a scaling of the word-gate length or a substrate-transient hot hole erase scheme, the charge loss in the lateral direction can be suppressed. Also, from the retention test, the latter scheme, substrate-transient hot hole (STHH), has a window independent of the word-gate length, which is better for the device scaling. (C) 2010 American Institute of Physics. [doi:10.1063/1.3508956]
The investigation of charge loss mechanism in a two-bit wrapped-gate nitride storage nonvolatile memory
(2010-11-01)
Ho, Y. H.
;
Chung, Steve S.
;
Chen, H. H.
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The charge loss mechanism of a two-bit wrapped-gate nitride storage nonvolatile memory is investigated. From retention measurements, it was shown that both vertical and lateral charge loss coexist. As a result of the misalignment of carriers, the lateral charge loss was caused by the hole accumulation near the junction and migrating toward the channel. By using a scaling of the word-gate length or a substrate-transient hot hole erase scheme, the charge loss in the lateral direction can be suppressed. Also, from the retention test, the latter scheme, substrate-transient hot hole (STHH), has a window independent of the word-gate length, which is better for the device scaling. (C) 2010 American Institute of Physics. [doi:10.1063/1.3508956]
X-ray microscopy and tomography detect the accumulation of bare and PEG-coated gold nanoparticles in normal and tumor mouse tissues
(2012-09-01)
Chien, C-C.
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Cheng, C-C.
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Chen, H. H.
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Hwu, Y.
;
Chu, Y. S.
"We demonstrate that, with appropriate staining, high-resolution X-ray microscopy can image complicated tissue structures-cerebellum and liver-and resolve large or small amounts of Au nanoparticles in these tissues. Specifically, images of tumor tissue reveal high concentrations of accumulated Au nanoparticles. PEG (poly(ethylene glycol)) coating is quite effective in enhancing this accumulation and significantly modifies the mechanism of uptake by reticuloendothelial system (RES) organs."