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991.
Optical orthogonal codes-new bounds and an optimal construction 总被引:9,自引:0,他引:9
Chung H. Kumar P.V. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1990,36(4):866-873
A technique for constructing optimal OOCs (optical orthogonal codes) is presented. It provides the only known family of optimal (with respect to family size) OOCs having λ=2. The parameters (n ,ω,λ) are respectively (p 2m-1, p m+1,2), where p is any prime and the family size is p m-2. Three distinct upper bounds on the size of an OOC are presented that, for many values of the parameter set (n ,ω,λ), improve upon the tightest previously known bound 相似文献
992.
Brown J.J. Lo D.C.W. Gardner J.T. Chung Y.K. Lee C.D. Forrest S.R. 《Electron Device Letters, IEEE》1989,10(12):588-590
In0.53Ga0.47As active feedback junction field-effect transistors (JFETs) for use in integrated transimpedance photoreceivers are discussed. By varying the gate-to-source voltage V GS, the resistance can be continuously tuned between 3 and 40 kΩ with a drain-to-source capacitance of <10 fF. The temperature coefficient of resistance is between -5 and -20 Ω/°C (for V GS less than the pinch-off voltage). The combination of large resistance and low capacitance can result in high receiver sensitivity without sacrificing amplifier dynamic range. The feedback FET was fabricated adjacent to 1.8-μm-gate-length JFETs with transconductances of 110 mS/mm, gate-to-source capacitances of 1.3 pF/mm, and DC amplifier voltage gains of 100. The compatibility of these transistor structures indicates that an integrated preamplifier with dynamically tunable bandwidth can be realized 相似文献
993.
A series of interpenetrating polymer networks (IPNs) based on unsaturated polyester/epoxy have been developed. The compatibility and interaction behavior of these IPNs have been investigated by DMA, DSC, SEM, FTIR and solid‐state NMR spectroscopies. The glass transition temperatures of IPNs were decreased and their transitions became broader as the content of unsaturated polyester increased in IPNs, based on our DMA and DSC study. The results of FTIR indicate that hydrogen bonding is present between the unsaturated polyester and epoxy. Insufficient degree of hydrogen bonding brought about immiscibility between IPN components. The analysis of proton spin‐lattice relaxation time in the rotating frame of the IPNs was also utilized to investigate molecular interaction between unsaturated polyester and epoxy. From relaxation curves, phase separation was found for the IPN samples with unsaturated polyester content higher than 30 %. This corroborates the DMA and SEM study. Copyright © 2004 Society of Chemical Industry 相似文献
994.
Jinwoo Choi Dong Gun Kam Daehyun Chung Srinivasan K. Govind V. Joungho Kim Swaminathan M. 《Advanced Packaging, IEEE Transactions on》2007,30(2):180-190
This paper presents near-field (NF) and far-field (FF) analysis of alternating impedance electromagnetic bandgap (AI-EBG) structure in packages and boards. Three test vehicles have been designed and fabricated for NF and FF measurements. Simulation results using a full-wave solver (SONNET) have been compared with measurement results. This paper investigates the radiation due to return current on different reference planes. The analysis results from simulations and measurements provide important guidelines for design of the AI-EBG structure based power distribution network for noise isolation and suppression in mixed-signal systems 相似文献
995.
Silicon carbide whisker-reinforced aluminium was fabricated by vacuum infiltration of liquid aluminium into a porous whisker
preform under an argon gas pressure, using an infiltration temperature of 665 °C. The volume fraction of whiskers ranged from
11% to 37%. No whisker pull-out was observed on the fracture surface for an infiltration temperature of 665 °C, but some whisker
pull-out was observed for an infiltration temperature of 720 °C. Both the tensile strength and ductility decreased with increasing
infiltration temperature above 665 °C. Tensile test results from room temperature to 300 °C are reported. They showed that
the quality of these composites was comparable to that of composites made by powder metallurgy or squeeze casting. The coefficient
of thermal expansion at 100–150 °C was decreased by 45% by the addition of 37 vol % whiskers. 相似文献
996.
997.
Jong Min Kim Jae-Ha Park Ho Girl Lee Hak-Joon Kim Sung-Jin Song Chang-Sung Seok Young-Ze Lee 《Journal of Thermal Spray Technology》2018,27(3):336-343
This research proposes a simple yet highly sensitive method based on electrical resonance of an eddy-current probe to detect delamination of thermal barrier coating (TBC). This method can directly measure the mechanical characteristics of TBC compared to conventional ultrasonic testing and infrared thermography methods. The electrical resonance-based method can detect the delamination of TBC from the metallic bond coat by shifting the electrical impedance of eddy current testing (ECT) probe coupling with degraded TBC, and, due to this shift, the resonant frequencies near the peak impedance of ECT probe revealed high sensitivity to the delamination. In order to verify the performance of the proposed method, a simple experiment is performed with degraded TBC specimens by thermal cyclic exposure. Consequently, the delamination with growth of thermally grown oxide in a TBC system is experimentally identified. Additionally, the results are in good agreement with the results obtained from ultrasonic C-scanning. 相似文献
998.
999.
Jieun Kim Jae Sung Lee Jong Bum Lee 《International journal of molecular sciences》2015,16(4):7738-7747
Fluorescent labeling is widely used to investigate the structural stability and changes to DNA nano- and microstructures. Despite this, the conventional method for observing DNA structures has several limitations in terms of cost-efficiency. This paper introduces a DNA spherical particle stained with DNA intercalating dyes (SYBR Green and SYTOX Orange) as tracers and reports the interaction between multiple dyes. The interference between the dyes was analyzed in terms of Förster resonance energy transfer (FRET) and competition. The changes in the fluorescence intensity by FRET were uniform, regardless of the sequence. The competition effect could occur when several dyes were added simultaneously. These properties are expected to help in the design of multicolor tracers in bioimaging and environmental applications. 相似文献
1000.
Yoon-Jung Moon Joseph Kwon Sung-Ho Yun Hye Li Lim Jonghyun Kim Soo Jung Kim Sung Gyun Kang Jung-Hyun Lee Seung Il Kim Young-Ho Chung 《International journal of molecular sciences》2015,16(5):9167-9195
The hyperthermophilic archaeon Thermococcus onnurineus NA1 has been shown to produce H2 when using CO, formate, or starch as a growth substrate. This strain can also utilize elemental sulfur as a terminal electron acceptor for heterotrophic growth. To gain insight into sulfur metabolism, the proteome of T. onnurineus NA1 cells grown under sulfur culture conditions was quantified and compared with those grown under H2-evolving substrate culture conditions. Using label-free nano-UPLC-MSE-based comparative proteomic analysis, approximately 38.4% of the total identified proteome (589 proteins) was found to be significantly up-regulated (≥1.5-fold) under sulfur culture conditions. Many of these proteins were functionally associated with carbon fixation, Fe–S cluster biogenesis, ATP synthesis, sulfur reduction, protein glycosylation, protein translocation, and formate oxidation. Based on the abundances of the identified proteins in this and other genomic studies, the pathways associated with reductive sulfur metabolism, H2-metabolism, and oxidative stress defense were proposed. The results also revealed markedly lower expression levels of enzymes involved in the sulfur assimilation pathway, as well as cysteine desulfurase, under sulfur culture condition. The present results provide the first global atlas of proteome changes triggered by sulfur, and may facilitate an understanding of how hyperthermophilic archaea adapt to sulfur-rich, extreme environments. 相似文献