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971.
Jea Hyeok Ryu Bo Gun Park Seuk Buom Kim Yong Joon Park 《Journal of Applied Electrochemistry》2009,39(7):1059-1066
The effect of surface area on the electrochemical properties and thermal stability of Li[Ni0.2Li0.2Mn0.6]O2 powders was characterized using a charge/discharge cycler and DSC (Differential Scanning Calorimeter). The surface area of
the samples was successfully controlled from ~4.0 to ~11.7 m2 g−1 by changing the molar ratio of the nitrate/acetate sources and adding an organic solvent such as acetic acid or glucose.
The discharge capacity and rate capability was almost linearly increased with increase in surface area of the sample powder.
A sample with a large surface area of 9.6–11.7 m2 g−1 delivered a high discharge capacity of ~250 mAh g−1 at a 0.2 C rate and maintained 62–63% of its capacity at a 6 C rate versus a 0.2 C rate. According to the DSC analysis, heat
generation by thermal reaction between the charged electrode and electrolyte was not critically dependent on the surface area.
Instead, it was closely related to the type of organic solvent employed in the fabrication process of the powder. 相似文献
972.
The microbes ofPseudomonas putida (KCTC1768) were fixed on the biofilter-packing media comprising an equivolume mixture of granular activated carbon (GAC)
and compost, by recycling the liquid medium containing incubatedPseudomonas putida (KCTC1768). A biofilter experiment was performed to observe its transient behavior under the operating condition of 2,180
ppmv of ethanol-inlet concentration and 158 g/m3/h of ethanol-inlet load for the five consecutive temperature-stages of operation ranging from 25 °C to 40 °C. For the five
temperaturestages of operation their removal efficiencies were measured and were compared with each other. The optimum operating
temperature of the biofilter turned out to beca. 30 °C, which was consistent with the previous experimental result of Lim and Park. However, the optimum incubation-temperatures
ofPseudomonas putida (KCTC1768) and the equivalent (i.e., NCIMB8858) were announced to be of 26 °C and 25 °C by Korea Collection for Type Cultures
(KCTC) and National Collections of Industrial, Food and Marine Bacteria (NCIMB), respectively. It was also confirmed by the
experiment in which the microbes were incubated in the same liquid medium as in the previous work of Lim and Park at temperature
ranging from 20 °C to 40 °C and their growth rates were subsequently measured. Thus, the optimum operating temperature of
a biofilter inoculated withPseudomonas putida (KCTC 1768) was proved to be 30 °C, which was higher than its optimum incubation-temperature byca. 5 °C 相似文献
973.
In-Soo Park 《Korean Journal of Chemical Engineering》2005,22(6):960-963
An analytical solution for the frequency response of a semi-batch adsorption vessel with sinusoidal modulation of molar flow
rate, loaded with inert core adsorbents is obtained for a linear isotherm coupled with intraparticle diffusion and external
film diffusion. The low-frequency limiting values of the in-phase and the out-of-phase characteristic functions of the frequency
response are found to be explicit functions of the size of the inert core and the external mass transfer parameter. Simulation
results of the in-phase and the out-of-phase characteristic functions show that there exist a crossover frequency and overshoot
of the in-phase characteristic function when external mass transfer resistance is present. 相似文献
974.
A multiple-effect diffusion still producing highly concentrated seawater was theoretically analyzed taking variations of the boiling point elevation (BPE) into account. The still consists of a series of seawater-soaked wicks stuck on closely-spaced parallel plates with the first plate steam-heated at 100°C and the last plate cooled in 30°C ambient air. Evaporation from the wicks increases the BPE more rapidly at downstream distances closer to exits of evaporating areas, and this increase reduces evaporation flux significantly at downstream regions on the wicks. An 80% heat recovery from products of hot condensate and concentrate reduces the steam consumption by 46%. The steam consumption decreases more rapidly with an increasing number of wicks than does the production rate; thus, a lower steam consumption ratio is observed for the still having more wicks. Narrowing the gaps between the plates greatly increases the production rate with a slight decrease in the steam consumption ratio. The still with 19 wicks with 1 m by 2 m evaporating areas, 5 mm gaps and 80% heat recovery produces 12 kg distillate and 3.3 kg concentrate of 0.16 kg/kg-water concentration per 1 kg steam consumption with a 26.4 kg/h distillate production rate. 相似文献
975.
In this study, analytical solutions for removal of a polydisperse aerosol by wet scrubbing were derived employing Brownian diffusion and inertial impaction as removal mechanisms. Size distribution of aerosol particles were assumed to be represented by a time-evolving log-normal function during the scrubbing process. Derived solutions were compared with the direct integration solution, which is not based on the log-normal assumption, showing good agreement. Error resulting from the log-normal assumption was shown to be greater in the impaction-dominant regime than in the diffusion-dominant regime due to higher size dependency of collision kernel which destructed log-normal shape of size distribution. The monodisperse model significantly overpredicted particle removal in the diffusion- and impaction-dominant size regimes due to its incapability of tracing average particle size change, while it underpredicted particle removal in the intermediate size range because of neglect of polydispersity effect. A new solution for the minimum collection efficiency particle diameter was also provided. The minimum efficiency diameter was shown not to be very sensitive to the scrubbing condition and to lie around for wide range of size and concentration of water drops. 相似文献
976.
Adsorption of heavy metals by brewery biomass 总被引:5,自引:0,他引:5
Tae-Young Kim Sun-Kyu Park Sung-Yong Cho Hwan-Beom Kim Yong Kang Sang-Done Kim Seung-Jai Kim 《Korean Journal of Chemical Engineering》2005,22(1):91-98
In this work, biosorption of lead, copper and cadmium by waste brewery yeast has been studied. The adsorption capacity for
lead, copper and cadmium on the biomass increased with the increasing temperature and the maximum uptakes were 0.465 mmolPb/g
(96.4 mg/g), 0.769 mmolCu/g (48.9 mg/g) and 0.127 mmolCd/g (14.3 mg/g) at 308 K. The Langmuir isotherm, favorable type, and
the pseudo second-order kinetic model represent our experimental data very well. The heat of biosorption was evaluated from
the Langmuir isotherm equation, and the biosorption of lead, copper and cadmium was endothermic reaction. 相似文献
977.
Water management plays an important role in obtaining high performance from a polymer electrolyte membrane fuel cell (PEMFC).
To reduce the volume and energy consumption of widely-used bubble humidifiers, membrane humidifiers were fabricated by using
an ultrafiltration (UF) membrane and Nafion membranes. The performance of the membrane humidifiers was examined as a function
of gas flow rate and operating temperature. A single cell was operated using the UF membrane humidifiers exhibiting almost
the same performance with that employing bubble humidifiers. 相似文献
978.
A D-Phenylalanine (Phe) imprinted terpolymer, Polyacrylonitrile-Poly(acrylic acid)-Poly(acryl amide) (Poly(AN-AA-AAm)) bead
was prepared by the wet-phase inversion method. Acrylamide (AAm) and acrylic acid (AA) were used as the functional monomer
and acrylonitrile (AN) was used as a physical cross linker. The characteristics of selective adsorption by the D-Phe imprinted
terpolymer beads were investigated at high concentrations of Phe racemate solution, 1 g Phe/L, and 10 g Phe/L. The adsorption
selectivity of the D-Phe imprinted terpolymer beads prepared by anin-situ implanting method reached 0.82 and 0.8 at 1.0 g and 10 g Phe/L racemate solution, respectively, and almost all of the adsorbed
D-Phe and about 43% of the adsorbed L-Phe were desorbed by 4% acetic acid. The uptake capacities of the terpolymer beads were
maintained for several repeated batches. 相似文献
979.
Gun Dae Lee Myung Jun Moon Jeong Hwan Park Seong Soo Park Seong Soo Hong 《Korean Journal of Chemical Engineering》2005,22(4):541-546
Catalytic activity, in conjunction with reaction mechanism, was studied in the methanation of CO and CO2 on three Raney Ni catalysts derived from different Ni-Al alloys using different leaching conditions. Main products were CH4 and CO2 in CO methanation, and CH4 and CO in CO2 methanation. Any other hydrocarbon products were not observed. Over all catalysts, CO methanation showed lower selectivity
to methane and higher activation energy than CO2 methanation. The catalyst derived from alloy having higher Ni content using more severe leaching conditions, namely higher
reaction temperature and longer extraction time, showed higher specific activity and higher selectivity to methane both in
CO and CO2 methanation. In CO and CO2 methanation on Raney Ni catalyst, catalytic activity was seen to have close relation with the activity to dissociate CO
This paper was presented at the 2004 Korea/Japan/Taiwan Chemical Engineering Conference held at Busan, Korea between November
3 and 4,2004. 相似文献
980.
Methyl Salicylate,a Soybean Aphid-Induced Plant Volatile Attractive to the Predator <Emphasis Type="Italic">Coccinella septempunctata</Emphasis> 总被引:5,自引:0,他引:5
Induced volatiles provide a signal to foraging predatory insects about the location of their prey. In Iowa, early in the growing season of soybean, Glycine max, many predacious seven-spotted lady beetles, Coccinella septempunctata, were observed on plants with heavy infestations of soybean aphid, Aphis glycines. We studied whether the attraction of this beetle is caused by the release of specific volatile compounds of soybean plants infested by aphids. Volatile compounds emitted by soybean plants infested by aphids were compared with those of undamaged, uninfested, and artificially damaged plants. Gas chromatography–mass spectrometry analyses revealed consistent differences in the profiles of volatile compounds between aphid-infested soybean plants and undamaged ones. Significantly more methyl salicylate was released from infested plants at both the V1 and V2 plant growth stages. However, release patterns of two other induced plant volatiles, (d)-limonene and (E,E)-α-farnesene, differed between the two plant growth stages. Gas chromatographic–electroantennographic detection of volatile extracts from infested soybean plants showed that methyl salicylate elicited significant electrophysiological responses in C. septempunctata. In field tests, traps baited with methyl salicylate were highly attractive to adult C. septempunctata, whereas 2-phenylethanol was most attractive to the lacewing Chrysoperla carnea and syrphid flies. Another common lady beetle, the multicolored Asian lady beetle, Harmonia axyridis, showed no preference for the compounds. These results indicate that C. septempunctata may use methyl salicylate as the olfactory cue for prey location. We also tested the attractiveness of some selected soybean volatiles to alate soybean aphids in the field, and results showed that traps baited with benzaldehyde caught significantly higher numbers of aphids. 相似文献