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991.
Jinho Jeong Youngwoo Kwon 《Microwave and Wireless Components Letters, IEEE》2004,14(10):457-459
A V-band 1/2 frequency divider is developed using harmonic injection-locked oscillator. The cross-coupled field effect transistors (FETs) and low quality-factor microstrip resonator are employed as a wide-band oscillator to extend the locking bandwidth. The second harmonic of free-running oscillation signal is injected to the gates of cross-coupled FETs for high-sensitivity superharmonic injection locking. The fabricated microwave monolithic integrated circuit frequency divider using 0.15-/spl mu/m GaAs pHEMT process showed a maximum locking range of 7.4 GHz (from 65.1 to 72.5 GHz) under a low power dissipation of 100 mW. The maximum single-ended output power was as high as -3 dBm. 相似文献
992.
JY Nam HK Kim KH Son SU Kim BM Kwon MY Han YJ Chung SH Bok 《Canadian Metallurgical Quarterly》1998,8(15):2001-2002
Actinomycin D, C2 and VII, cyclic peptides, inhibited Grb2 SH2 domain association (IC50 5-7 microM) with a phosphotyrosine containing peptide derived from the Shc protein (pTyr317). Actinomycins are the first examples of nonphosphorylated natural ligands of SH2 domain. 相似文献
993.
GN Patrick P Zhou YT Kwon PM Howley LH Tsai 《Canadian Metallurgical Quarterly》1998,273(37):24057-24064
Cyclin-dependent kinase 5 (Cdk5) was originally isolated by its close homology to the human CDC2 gene, which is a key regulator of cell cycle progression. However, unlike other Cdks, the activity of Cdk5 is required in post-mitotic neurons. The neuronal-specific p35 protein, which shares no homology to cyclins, was identified by virtue of its association and activation of Cdk5. Gene targeting studies in mice have shown that the p35/Cdk5 kinase is required for the proper neuronal migration and development of the mammalian cortex. We have investigated the regulation of the p35/Cdk5 kinase. Here we show that p35, the activator of Cdk5, is a short-lived protein with a half-life (t1/2) of 20 to 30 min. Specific proteasome inhibitors such as lactacystin greatly stabilize p35 in vivo. Ubiquitination of p35 can be readily demonstrated in vitro and in vivo. Inhibition of Cdk5 activity by a specific Cdk inhibitor, roscovitine, or by overexpression of a dominant negative mutant of Cdk5 increases the stability of p35 by 2- to 3-fold. Furthermore, phosphorylation mutants of p35 also stabilize p35 2- to 3-fold. Together, these observations demonstrate that the p35/Cdk5 kinase can be subject to rapid turnover in vivo and suggest that phosphorylation of p35 upon Cdk5 kinase activation plays a autoregulatory role in p35 degradation mediated by ubiquitin-mediated proteolysis. 相似文献
994.
Kwang Hyun Ryu Namic Kwon Myung Hee Seo Myung Hoon Lee Gi Jung Nam No Heung Kwak 《Advanced Packaging, IEEE Transactions on》2006,29(4):701-706
Anisotropic conductive film (ACF) bonding between liquid crystal displays (LCDs) and driver integrated circuits (ICs) is one of the key technologies for developing high-resolution LCDs. The bonding pitch between LCD and tape carrier package (TCP), which influences the total reliability of LCD modules, depends on the characteristics and bonding conditions of ACF used. So, the bonding process between TCP and a glass panel with ACF using a high-power diode laser as a heat source for curing is preliminarily tested in this experiment. Also, laser transient thermal simulation was performed to analyze the thermal response of the assembly process for a package using ACF. The temperature on the ACF layer goes up to 180 degC (ACF curing temperature) within 1 s after exposure to laser light. This paper reports an effective bonding method using a diode laser, which accomplishes a fine-pitch ACF bonding and determines the optimum ACF bonding condition effectively 相似文献
995.
A three-dimensional musculoskeletal model was used to predict the trunk and lower extremity muscle activity required to stabilize the body while performing dynamic tasks in the seated posture. We studied seven subjects performing four tasks consisting of cyclic or single-directional movements of a hand-held weight in the sagittal plane. Five different optimization schemes involving the minimization of muscle forces, muscle stresses, or joint force components were used to predict the 64 muscle force-time histories. A quantitative method was used to compare prediction schemes by correlating predicted muscle forces with measured myoelectric data and ranking the efficacy of each scheme for different tasks and subjects. The results showed that (1) the trunk and lower extremity muscles play an important role in stabilizing the seated posture in these tasks. (2) the most successful muscle force prediction scheme was not the same for all seven subjects performing a given task, or for a given subject performing all four tasks, and (3) these linear optimization techniques successfully predicted activity in up to 10 of the 15 muscles whose myoelectric signals were actually monitored. 相似文献
996.
J.H. Ha J.C. Kim Y.K. Kim M. Youn S.J. Chae H.T. Chung J.H. Choi C.S. Lee J.U. Kwon C.-B. Moon J.S. Chai Y.S. Kim J.D. Lee 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1994,350(3):411-414
Energy measurement of 50 MeV proton beam produced on the AVF MC-50 Cyclotron was conducted using a detector telescope with a NaI(Tl) scintillator as an E counter. Protons of various energies, elastically and inelastically scattered from the 12C target nucleus were measured at four different angles of 35°, 40°, 50° and 55°. We applied the chi-square method to determine the beam energy, which showed a well defined minimum chi-square corresponding to a beam energy of 49.6 ± 2.3 MeV at the 68% confidence level. Also the light output response of NaI(Tl) to proton energies between 31 and 44 MeV is linear within 0.5 MeV and is in good accord with the recent result of Romero et al. [Nucl. Instr. and Meth. A 301 (1991) 241]. 相似文献
997.
998.
A known jamming state information (JSI) scheme for a coded frequency-hopped M-ary frequency-shift-keying (FH/MFSK) system under partial-band noise jamming, plus additive white Gaussian noise, utilizes the maximum a posteriori (MAP) rule based on the total energy received in the M-tone signaling bands. It is assumed that the knowledge of partial-band noise jamming fraction is available to the JSI generator. Because this scheme reduces the M-dimensional information into one dimension, i.e., the total energy, the generated JSI may not be the best. In this paper, a neural network approach to the JSI generation is presented. The efficiency of the new JSI generator with known partial-band noise jamming fraction is compared with the MAP generator. The neural network scheme is then generalized to increase its robustness by allowing for an unknown partial-band noise jamming fraction. The neural network JSI generator with or even without knowledge of jamming fraction offers significantly better performance for a coded FH/MFSK communication system than the MAP JSI generator for high code rate. 相似文献
999.
Wook Hyun Kwon Beom Jin Chung Jung Woo Park Gi Won Lee Man Chul Yoon 《Power Delivery, IEEE Transactions on》1992,7(1):160-166
The authors present a real-time network using an optical-fiber transmission line and implement the prototype network system for a proposed integrated digital protection and control system. A single network structure is investigated which supports both protection and control functions. It realizes high-speed communications among the power equipment. As a communication protocol the IEEE 802.4 token passing bus protocol with fiber-optic medium is employed, taking substation environments into account. Two implementation schemes for the communication scheme are suggested which are based on the IEEE 802.4 specifications. An allocation method is presented for setting the network parameter and some performance indices are analyzed. Through the experiments, it is shown that the proposed prototype network system satisfies the necessary requirements in substations 相似文献
1000.
An integrated numerical and experimental framework for modeling of CTB and GD1b ganglioside binding kinetics 下载免费PDF全文
Dongheon Lee Akshi Singla Hung‐Jen Wu Joseph Sang‐Il Kwon 《American Institute of Chemical Engineers》2018,64(11):3882-3893
A mathematical model is developed and validated for a multistep binding process between cholera toxin subunit B (CTB) and GD1b receptors that precedes cholera infection. To study the dynamics of the complex CTB‐GD1b binding mechanisms, cooperative binding effect and GD1b receptor aggregation in the host cell membrane are considered. More reliable parameters for the CTB‐GD1b binding kinetics are estimated by quantitatively calibrating the proposed multistep binding model against the experimental measurements obtained from the novel nanocube‐based biosensor. Specifically, a numerical scheme that includes the sensitivity analysis, parameter estimation and dynamic optimization is implemented for the model calibration. Through this scheme, identifiable model parameters are determined. After those selected parameters are estimated, the calibrated model and the experimental measurements were in reasonable agreement for different CTB and GD1b concentrations, which shows a promising approach for identification of the kinetics of CTB binding to the host cell membrane. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3882–3893, 2018 相似文献