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31.
In this paper, we investigate the effect of water (H2O) molecules evolving from silicon dioxide (SiO2) film deposited by low pressure chemical vapor deposition (LPCVD) at 670 °C on the transistor characteristic of an electrically erasable programmable read only memory (EEPROM) cell. Fourier Transform Infra red (FT-IR) analysis reveals that H2O is captured during film deposition and diffused to silicon surface during high thermal processing. The diffused H2O molecules lower threshold voltage (Vt) of cell transistor and, thus, leakage current of the cell transistor is increased. In erased cell, Vt lowering is 0.25 V in which it increases leakage current of cell transistor from 1 to 100 pA. This results in the lowering of high voltage margin of a 512 Kb EEPROM from 2.8 to 2.6 V at 85 °C. 相似文献
32.
The effect of variables on efficiency of SO2 removal from a simulated waste gas by use of ammonia solution was studied. The variables were gas, feed solution and recirculation
flow rate, SO2 concentration in the gas phase, NH3 concentration in the ammonia solution, and pH in scrubber effluent solutions.
The scrubber was 3“ — OD methyl metacrylate column packed with 1 •4” — plastic Rasching rings in 90 cm packed height.
Solution analysis was performed by Palmrose method and pH meter. The following empirical equations were obtained by regression
analysis; EFF = 33.52 G0.0552 F0.118 R0.772 EFF = 64.10 S0.143 N0.0153 kG = 3.51 x 10-6 G1.160 L0.647 相似文献
33.
A dispatching method is suggested for automated guided vehicles by using an auction algorithm. The dispatching method in
this study is different from traditional dispatching rules in that it looks into the future for an efficient assignment of
delivery tasks to vehicles and also in that multiple tasks are matched with multiple vehicles. The dispatching method in this
study is distributed in the sense that the dispatching decisions are made through communication among related vehicles and
machines. The theoretical rationale behind the distributed dispatching method is also discussed. Through a simulation study,
the performance of the method is compared with that of a popular dispatching rule.
RID="*"
ID="*" The research was financially supported by the Sasakawa Scientific Research Grant from The Japan Science Society. The
original version of the simulation program is provided by Professor Jae Yeon Kim at Dong Yang University, Korea.
Correspondence to: J. K. Lim 相似文献
34.
Nd-doped Bi4Ge3O12 (Nd:BGO) crystals were successfully grown in the auto-diameter control system equipped with a frequency weighing sensor with
the Czochralski method. The Nd3+ ion doping level was varied from 0.25 to 2.5 at.%. The crystals were transparent and of light purple color, with a typical
size of about 20 mm in diameter and 50 mm in length. The effective distribution coefficient (keff) of Nd3+ ion was about 0.957 irrespective of concentration, and the Nd3+ ions were distributed homogeneously throughout the crystal. The doping concentration (pi) of active ion in Nd:BGO crystal was 2.54x1020 ions/cm3, which is higher than that in the Nd:YAG crystal. Therefore, the Nd:BGO crystal was judged to be more suitable for the laser
diode pumping microchip laser material where size reduction was desirable. 相似文献
35.
H Kook JH Rhee SE Lee SY Kang SS Chung KW Cho YH Baik 《Canadian Metallurgical Quarterly》1999,365(2-3):267-272
Recently we reported that Vibrio vulnificus hemolysin, an exotoxin produced by V. vulnificus, dilates rat thoracic aorta via elevated cGMP levels without affecting nitric oxide synthase. We investigated the mechanism further by observing the guanylyl cyclase activities in cytosolic, membrane, unfractionated, or reconstituted preparations. Hemolysin did not activate guanylyl cyclase in the membrane or cytosolic fraction, while it activated guanylyl cyclase in unfractionated or reconstituted preparation. The increased activity was not inhibited by the HS-142-1, a microbial polysaccharide which antagonizes atrial natriuretic peptide receptor, or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), a soluble guanylyl cyclase inhibitor. However, it was attenuated by 6-(phenylamino)-5,8-quinolinedione (LY 83.583), which inhibits the catalytic domain of both guanylyl cyclases, and by cholesterol, which blocks hemolysin-incorporation into the membrane. Removing ATP, a cofactor of particulate guanylyl cyclase, attenuated the activation and ATPgammaS, a non-phosphorylating analog, restored it. These results suggest that V. vulnificus hemolysin activates particulate guanylyl cyclase via hemolysin incorporation into the vascular smooth muscle cell membrane in cooperation with certain unidentified cytosolic component(s). 相似文献
36.
Chang Kook Hong Kap Seung Yang Seung Hyun Oh Jou‐Hyeon Ahn Baik‐Hwan Cho Changwoon Nah 《Polymer International》2008,57(12):1357-1362
BACKGROUND: The aim of the work presented was to determine the morphology development and relevant change in fibre diameter of a binary polymer blend system during an electrospinning process. The size of the fibre diameter is one of the important factors determining the general properties of non‐woven mats formed from electrospun fibres. RESULTS: The morphology and diameter of electrospun polyacrylonitrile (PAN)/poly(methyl methacrylate) (PMMA) blends were investigated as a function of blend ratio using scanning electron microscopy. The diameter of the electrospun PAN/PMMA fibres decreased with increasing PMMA content up to 50 wt%, and then increased again with further increase of PMMA. After thermal treatment, the fibres shrank, and an irregularly shaped morphology was observed. CONCLUSION: The electrospinning of incompatible PAN/PMMA blends leads to a microphase‐separation morphology of fibres. A phase inversion occurs at a PMMA content of between 50 and 75 wt%. Due to the phase inversion, the fibre diameter shows a minimum value at the relevant composition. Copyright © 2008 Society of Chemical Industry 相似文献
37.
Polymer blend (poly(ethylene oxide) (PEO)–poly(propylene oxide) (PPO)) systems with two different mole ratios, complexed with LiCF3SO3 salt, have been characterized at various temperatures and compositions using a thermo‐optical analysis (TOA) technique. We also developed a new melting point depression theory based on the modified perturbed hard sphere chain model to interpret phase behavior of polymer blend electrolyte systems. The obtained results show that the eutectic points move toward higher Tm and lower weight fraction of salt with decreasing PEO mole ratio and also indicate that the mole ratio of PEO–PPO for each polymer blend plays an important role in determining the eutectic point of the polymer blend system. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2314–2319, 2005 相似文献
38.
Direct quantitative comparisons of four different probe methods were performed for determination of local gas holdup, vertical bubble length, bubble rising velocity, and bubble frequency. The methods include vertically projecting electroresistivity, horizontally projecting electroresistivity, U-shape light reflection, and light transmission. The measured bubble properties strongly depended on the size and configuration of the probe tips. The light transmission probe developed in this work can be used to determine the bubble properties effectively. In order to minimize interferences with bubble flow, the size of probe tip should be small as possible and its configuration must be vertically projecting. 相似文献
39.
Adsorption isotherms for m-cresol, quinoline, and 1-naphthol onto silica gel in n-hexane at 30°C were measured in the concentration
range of 1–30 mole/m3. The experimental results for m-cresol and quinoline were well represented by the generalized Toth isolherm, and for 1-naphthol
by the superimposed two sites Langmuir model. At low concentrations the adsorbed amounts onto silica gel were decreased in
sequence of quinoline, 1-naphthol, and m-cresol. However as the concentration increased, the sequence was reversed.
For binary systems, the competitive adsorption was quantitatively studied by introducing the competitive adsorption coefficient.
The relative affinity of quinoline with respect to silica surface was larger than those of the other two components. 相似文献
40.
Development of a risk assessment program for chemical terrorism 总被引:1,自引:0,他引:1
Younghee Lee Jinkyung Kim Junghwan Kim Jiyong Kim Il Moon 《Korean Journal of Chemical Engineering》2010,27(2):399-408
The study focuses on assessing the security risk of the terrorism in the chemical industry. This research modifies conventional
risk assessment methods for including terrorism and sabotage scenarios. The objective of this risk assessment is to identify
security hazards, threats and vulnerabilities facing each target facility, and to find the adequate countermeasures to protect
the public, workers, national interest, environment, and companies. This study results in implementing software to analyze
the possibility of terrorism and sabotage. This program includes five steps: asset characterization, threat assessment, vulnerability
analysis, risk assessment and new countermeasures. It is a systematic, risk-based approach in which risk is a function of
the severity of consequences of an undesired event, the likelihood of adversary attack, and the likelihood of adversary success
in causing the undesired event. The reliability of this method is verified by the dock zone case. This study suggests an effective
approach to chemical terrorism response management. 相似文献