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排序方式: 共有1371条查询结果,搜索用时 15 毫秒
11.
Oh Kee Kwon Kang Ho Kim Eun Deok Sim Jong Hoi Kim Hyun Soo Kim Kwang Ryong Oh 《Photonics Technology Letters, IEEE》2005,17(3):537-539
Tunable external-cavity lasers with low power variation over a broad tuning range are demonstrated using asymmetric multiple quantum-wells with a wide and flat gain. For a 2.8-/spl mu/m-wide ridge waveguide laser of cavity length 380 /spl mu/m, when used in a grating external cavity and with an antireflection coating on one facet of laser diode chip, the power variation of less than -1 dB is obtained over a range of 80 nm. This extremely low power variation is a direct result of the spectrally flat gain. 相似文献
12.
Ki-Whan Song Yong Kyu Lee Jae Sung Sim Hoon Jeoung Jong Duk Lee Byung-Gook Park You Seung Jin Young-Wug Kim 《Electron Devices, IEEE Transactions on》2005,52(8):1845-1850
We have developed an integration technology for the single electron transistor (SET)/CMOS hybrid systems. SET and CMOS transistors can be optimized without any possible degradation due to mixing dissimilar devices by adopting just one extra mask step for the separate gate oxidation (SGOX). We have confirmed that discrete devices show ideal characteristics required for the SET/CMOS hybrid systems. An SET shows obvious Coulomb oscillations with a 200-mV period and CMOS transistors show high voltage gain. Based on the hybrid process, new hybrid circuits, called periodic multiband filters, are proposed and successfully implemented. The new filter is designed to perform a filtering operation according to the periodic multiple blocking bands of which a period is originated from the SET. Such a novel function was implemented efficiently with a few transistors by making full use of the periodic nature of SET characteristics. 相似文献
13.
Jung-Ho Song Jung-Woo Park Eun-Deok Sim Yongsoon Baek 《Photonics Technology Letters, IEEE》2005,17(9):1791-1793
Amplified spontaneous emission (ASE) spectra of passive waveguide integrated lasers have been studied to estimate the coupling efficiency and the reflectivity at the butt-joints between active and passive waveguides. A new method has been proposed for the analysis of ASE to extract the coupling efficiency and reflectivity at the butt-joints. This method was applied experimentally to estimate the coupling and reflection of the passive waveguide integrated lasers with different amounts of vertical misalignments of active and passive waveguides. 相似文献
14.
Chadwin D. Young Gennadi Bersuker Yuegang Zhao Jeff J. Peterson Joel Barnett George A. Brown Jang H. Sim Rino Choi Byoung Hun Lee Peter Zeitzoff 《Microelectronics Reliability》2005,45(5-6):806
Effects of constant voltage stress (CVS) on gate stacks consisting of an ALD HfO2 dielectric with various interfacial layers were studied with time dependent sensing measurements: DC I–V, pulse I–V, and charge pumping (CP) at different frequencies. The process of injected electron trapping/de-trapping on pre-existing defects in the bulk of the high-κ film was found to constitute the major contribution to the time dependence of the threshold voltage (Vt) shift during stress. The trap generation observed with the low frequency CP measurements is suggested to occur within the interfacial oxide layer or the interfacial layer/high-κ interface, with only a minor effect on Vt. 相似文献
15.
Jorge Laine Joaquin Brito Francisco Severino Germán Castro Patricia Tacconi Simón Yunes José Cruz 《Catalysis Letters》1990,5(1):45-54
The effect of prereduction on CO oxidation activity of unsupported copper-chromite oxide catalysts was examined. Results were found to be in good agreement with two mechanisms for a surface copper enrichment due to CO prereduction which produced an activity increase in the copper-chromite catalyst. 相似文献
16.
17.
Simão P. B. Teixeira Rui M. A. Domingues Pedro S. Babo Dominika Berdecka Margarida S. Miranda Manuela E. Gomes Nicholas A. Peppas Rui L. Reis 《Advanced functional materials》2021,31(4):2003934
Growth factors (GFs) are biomolecules with potent biological effects but inherent limitations hinder their potential as therapeutic agents and cell culture supplements in tissue engineering and regenerative medicine (TERM). Biomaterials that sequester endogenous GFs by affinity binding might circumvent such limitations and thus are being increasingly investigated. Here, molecularly imprinted nanoparticles (MINPs) are proposed as specific abiotic ligands for GFs. As a proof of concept, a conformational epitope of transforming growth factor-β3 (TGF-β3) is designed and surface imprinted onto polyacrylamide-based nanoparticles by inverse microemulsion polymerization. It is found that, depending on the polymerization mixture composition, MINPs can recognize and preferentially bind TGF-β3, either in noncompetitive assays or from a complex human fluid (platelet lysate). Substrates functionalized with MINPs are then used for 2D culture of adipose-derived stem cells. Remarkably, gene and protein expression profiles show a marked upregulation of SOX-9, suggesting activation of TGF-β3 signaling pathways without requiring supplementation with exogenous GF. Likewise, culturing these cells in pellets incorporating MINPs previously incubated with platelet lysate results in higher collagen II-rich matrix deposition, compared to pellets incorporating non-imprinted nanoparticles. In summary, results suggest MINPs can be used as cost-effective, stable, and scalable alternative abiotic GF ligands to guide cell fate in TERM applications. 相似文献
18.
Jae-Yoon Sim Hongil Yoon Ki-Chul Chun Hyun-Seok Lee Sang-Pyo Hong Kyu-Chan Lee Jei-Hwan Yoo Dong-Il Seo Soo-In Cho 《Solid-State Circuits, IEEE Journal of》2003,38(4):631-640
To verify three important circuit schemes suitable for DRAMs in mobile applications, a 1.8-V 128-Mb SDRAM was implemented with a 0.15-/spl mu/m technology. To achieve an ideal 33% efficiency, the double boosting pump uses two capacitor's series connection at pumping phase, while they are precharged in parallel. The hybrid folded current sense amplifier together with a novel replica inverter connection improved power and speed performances. Also, a dual-referenced adjustment scheme for a temperature sensor was proposed to allow a very high accuracy in tuning. Without loss in productivity, the implemented dual-referenced searching technique achieved tuning error of less than /spl plusmn/2.5/spl deg/C. 相似文献
19.
Geonwoo Kang Minkyung Kim Huisuk Yang Jiwoo Shin Jeeho Sim Hyeri Ahn Mingyu Jang Youseong Kim Hye Su Min Hyungil Jung 《Advanced functional materials》2023,33(11):2370066
Dissolving microneedle (DMN) is an attractive alternative to parenteral and enteral drug administration owing to its painless self-administration and safety due to non-generation of medical waste. For reproducible and efficient DMN administration, various DMN application methods, such as weights, springs, and electromagnetic devices, have been studied. However, these applicators have complex structures that are complicated to use and high production costs. In this study, a latch applicator that consists of only simple plastic parts and operates via thumb force without any external complex device is developed. Protrusion-shaped latches and impact distances are designed to accumulate thumb force energy through elastic deformation and to control impact velocity. The optimized latch applicator with a pressing force of 25 N and an impact velocity of 5.9 m s−1 fully inserts the drug-loaded tip of the two-layered DMN into the skin. In an ovalbumin immunization test, DMN with the latch applicator shows a significantly higher IgG antibody production rate than that of intramuscular injection. The latch applicator, which provides effective DMN insertion and a competitive price compared with conventional syringes, has great potential to improve delivery of drugs, including vaccines. 相似文献
20.
Jai-Hoon Sim Jae-Kyu Lee Kinam Kim 《Electron Devices, IEEE Transactions on》1999,46(6):1212-1217
In this paper, the cell transistor design issues for the Gbit level DRAM's with the isolation pitch of less than 0.2 μm caused by the inverse-narrow-channel effect (INCE) and the neighboring storage-node E-field penetration effect (NSPE) will be discussed. Then we propose novel DRAM cell transistor structure by employing metallic shield inside the shallow trench isolation (STI). As confirmed by three-dimensional (3-D) device simulation results, by suppressing the inverse narrow-channel effect and the neighboring storage-node E-field penetration effect using metallic shield inside STI, we can obtain reliable cell transistors with low-doped substrate, low junction leakage current and uniform VTH a distribution regardless of the active width variation 相似文献