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991.
A key problem in the design of large mixed-signal circuits is the noise caused by the coupling of digital signals into the substrate. This paper describes methods that allow circuit designers to model efficiently such substrate noise in large mixed-signal SPICE designs. In the light of these techniques a new methodology is presented for efficiently modelling the substrate noise caused by current injection and its coupling to analogue signals; this is then extended to provide a real-time modelling capability. The practicality and the numerical efficiency of the methods are demonstrated on several prototype example circuits 相似文献
992.
Tae‐Woo Lee Mu‐Gyeom Kim Sang Hun Park Sang Yeol Kim Ohyun Kwon Taeyong Noh Jong‐Jin Park Tae‐Lim Choi Jong Hyeok Park Byung Doo Chin 《Advanced functional materials》2009,19(12):1863-1868
The short device lifetime of blue polymer light‐emitting diodes (PLEDs) is still a bottleneck for commercialization of self‐emissive full‐color displays. Since the cathode in the device has a dominant influence on the device lifetime, a systematic design of the cathode structure is necessary. The operational lifetime of blue PLEDs can be greatly improved by introducing a three‐layer (BaF2/Ca/Al) cathode compared with conventional two‐layer cathodes (BaF2/Al and Ba/Al). Therefore, the roles of the BaF2 and Ca layers in terms of electron injection, luminous efficiency, and device lifetime are here investigated. For efficient electron injection, the BaF2 layer should be deposited to the thickness of at least one monolayer (~3 nm). However, it is found that the device lifetime does not show a strong relation with the electron injection or luminous efficiency. In order to prolong the device lifetime, sufficient reaction between BaF2 and the overlying Ca layer should take place during the deposition where the thickness of each layer is around that of a monolayer. 相似文献
993.
994.
Energy Harvesting: High‐Performance Piezoelectric,Pyroelectric, and Triboelectric Nanogenerators Based on P(VDF‐TrFE) with Controlled Crystallinity and Dipole Alignment (Adv. Funct. Mater. 22/2017) 下载免费PDF全文
995.
A Colorimetric Hydrocarbon Sensor Employing a Swelling‐Induced Mechanochromic Polydiacetylene 下载免费PDF全文
Dong‐Hoon Park Jaesung Hong In Sung Park Chan Woo Lee Jong‐Man Kim 《Advanced functional materials》2014,24(33):5186-5193
Exceptional challenges have confronted the rational design of colorimetric sensors for saturated aliphatic hydrocarbons (SAHCs). The main reasons for this difficulty are the extremely nonpolar nature of these targets and their lack of functional groups that can interact with probes. By taking advantage of a mechanochromic conjugated polydiacetylene (PDA) and the hydrocarbon‐induced swelling properties of polydimethylsiloxane (PDMS), a sensor film that enables simple, colorimetric differentiation between a variety of C5 to C14 aliphatic hydrocarbons is fabricated. The unprecedented PDA–PDMS composite sensor undergoes a blue‐to‐red colorimetric transition on a timescale that is dependent on the chain length of the hydrocarbon target. In addition, the development of the red color is directly proportional to the swelling ratio of the film. This straightforward approach enables naked‐eye differentiation between n‐pentane and n‐heptane. The versatility of the sensor system is demonstrated by using it for the colorimetric determination of kerosene in adulterated diesel oil. Finally, the observation that a PDA microcrystal in the film undergoes significant expansion and tearing in concert with a blue‐to‐red colorimetric transition during the swelling process provides direct evidence for the mechanism for the mechanochromic behavior of the PDA. 相似文献
996.
Jong Pil Kim Woo Young Choi Jae Young Song Sang Wan Kim Jong Duk Lee Byung-Gook Park 《Electron Devices, IEEE Transactions on》2007,54(11):2969-2974
A novel asymmetric MOSFET with no lightly doped drain on the source side is simulated on bulk Si using a device simulator (SILVACO). To overcome the problems of the conventional asymmetric process, a novel asymmetric MOSFET using a mesa structure and a sidewall spacer gate is proposed, and it provides a self-alignment process, aggressive scaling, and better uniformity. First of all, we have compared the simulated characteristics of the asymmetric and symmetric MOSFETs. Basically, both asymmetric and symmetric MOSFETs have an n-type channel and the same physical parameters. Compared with the symmetric MOSFET, the asymmetric MOSFET shows better device performance. Moreover, we have successfully fabricated 50-nm asymmetric NMOSFETs based on simulation results and investigated its operation and characteristics. 相似文献
997.
Surface Chemistry of Vitamin: Pyridoxal 5′‐Phosphate (Vitamin B6) as a Multifunctional Compound for Surface Functionalization 下载免费PDF全文
Jung Seung Lee Kyuri Kim Kihong Lee Joseph P. Park Kisuk Yang Seung‐Woo Cho Haeshin Lee 《Advanced functional materials》2015,25(30):4754-4760
Vitamins are non‐toxic compounds that perform a variety of biological functions and also available in a large quantity. Other than the usage as food supplements, few attempts have been made to use them as functional materials. In this study, we report that vitamin B6, pyridoxal 5′‐phosphate (PLP), is a multi‐functional molecule for oxide surface chemistry. PLP‐immobilized surfaces exhibit superhydrophilicity and even hemophilicity, enhancing proliferation, migration, and differentiation of mammalian cells. Unlike existing molecules used so far in surface modification, PLP has an intrinsic chemical reactivity toward biomacromolecules due to the presence of the aldehyde group. In fact, RGD peptide is covalently tethered onto PLP surfaces directly in one step without any chemical activation. Furthermore, PLP‐functionalized implant device showed rapid bone healing. As vitamin B6 is a FDA approved molecule for human usage, the surface chemistry of vitamin B6 potentially allows a fast route for surface functionalized medical devices into clinic. 相似文献
998.
A computer-aided diagnosis (CAD) algorithm identifying breast nodule malignancy using multiple ultrasonography (US) features and artificial neural network (ANN) classifier was developed from a database of 584 histologically confirmed cases containing 300 benign and 284 malignant breast nodules. The features determining whether a breast nodule is benign or malignant were extracted from US images through digital image processing with a relatively simple segmentation algorithm applied to the manually preselected region of interest. An ANN then distinguished malignant nodules in US images based on five morphological features representing the shape, edge characteristics, and darkness of a nodule. The structure of ANN was selected using k-fold cross-validation method with k = 10. The ANN trained with randomly selected half of breast nodule images showed the normalized area under the receiver operating characteristic curve of 0.95. With the trained ANN, 53.3% of biopsies on benign nodules can be avoided with 99.3% sensitivity. Performance of the developed classifier was reexamined with new US mass images in the generalized patient population of total 266 (167 benign and 99 malignant) cases. The developed CAD algorithm has the potential to increase the specificity of US for characterization of breast lesions. 相似文献
999.
The high-field mobility behavior of silicon MOSFETs fabricated with reoxidized nitrided oxide (ONO) gate dielectrics has been investigated. Measurements have been performed at both room temperature and 77 K on both n- an p-channel FETs, for both ONO and conventional SiO 2 films. While the peak electron mobility is much higher for standard SiO2, a crossover occurs in the high-field region beyond which ONO transistors exhibit higher mobility. The crossover voltage is reduced at 77 K. Measurements intended to gain further insight into this phenomenon suggest that differences in surface roughness scattering, or the buried-channel nature of an ONO NMOS transistor, are the most likely explanations for the high-field mobility behavior observed 相似文献
1000.
Richard Wood Ian Bruce C.-B. Moon Woo Young Kim Peter Mascher 《Organic Electronics》2012,13(12):3254-3258
This paper uses the results of the characterization of amorphous semiconductor thin film transistors (TFTs) with the quasi-permanent memory structure referred to as silicon oxide nitride semiconductor (SONOS) gates, to model spiking neural circuits. SONOS gates were fabricated and characterized. In addition, MOSFETs using organic copper phthalocyanine (CuPc) were fabricated with these SONOS gates to demonstrate proof of concept performance. Analog spiking circuits were then modeled using these low performance TFTs to demonstrate the general suitability of organic TFTs in neural circuits. The basic circuit utilizes a standard comparator with charge and discharge circuits. A simple Hebbian learning circuit was added to charge and discharge the SONOS device. The use of these elements allows for the design and fabrication of high-density 3-dimensional circuits that can achieve the interconnect density of biological neural systems. 相似文献