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991.
Bates Paul A.; McGregor Malcolm J.; Islam Suhail A.; Sattentau Quentin J.; Sternberg Michael J.E. 《Protein engineering, design & selection : PEDS》1989,3(1):13-21
A predicted three-dimensional structure of the two N-terminalextracellular domains of human CD4 antigen, a cell surface glycoprotein,is reported. This region of CD4, particularly the first domain,has been identified as containing the binding region for theenvelope gp120 protein of the human immuno-deficiency virus.The model was predicted based on the sequence homology of eachdomain with the variable light chain of immunoglobulins. Theframework ß-sheet regions were taken from the crystalcoordinates of REI. For one region in the first domain of CD4there was an ambiguity in the alignment with REI and two alternatemodels are presented. Loops connecting the framework were modeledfrom fragments selected from a database of main chain coordinatesfrom all known protein structures. Residues identified as involvedin binding gp120 have been located in several other studieswithin the first domain of CD4. Epitopes from eight monoclonalantibodies have been mapped onto residues in both domains. Competitionof these antibodies with each other and with gp120 can be interpretedfrom the structural model. 相似文献
992.
Enhancement of combustion efficiency with mixing ratio during fluidized bed combustion of anthracite and bituminous blended coal 总被引:1,自引:0,他引:1
Jeong-Gook Jang Mi-Ran Kim Ki-Ho Lee Jea-Keun Lee 《Korean Journal of Chemical Engineering》2002,19(6):1059-1065
In order to investigate the effect of mixing ratio of bituminous coal to blended coal on the enhancement of combustion efficiency,
combustion experiments of blended coal with anthracite and bituminous are done in a laboratory scale fluidized bed combustor
(10.8 cm ID and 170 cm height). The gross heating values of anthracite and bituminous coal used in this study are 2,810 cal/g
and 6,572 cal/g, respectively. Experimental parameters are fuel feed rate, superficial gas velocity and mixing ratio of bituminous
coal to blended coal. The combustion efficiency increases with the mixing ratio of bituminous coal due to the lower unburned
carbon losses and higher burning velocity of bituminous coal. The rate of combustion in the combustor was increased with mixing
ratio resulted from a higher burning velocity of bituminous coal. The measured combustion efficiency experimentally is about
3.5-12.4% higher than that of the calculated value based on the individual combustion of anthracite and bituminous coal under
the same operating conditions. The optimum mixing ratio (MR) of bituminous coal determined is around 0.75 in this study.
This paper is dedicated to Professor Dong Sup Doh on the occasion of his retirement from Korea University. 相似文献
993.
We propose a face detection method based on skin color likelihood via a boosting algorithm which emphasizes skin color information while deemphasizing non-skin color information. A stochastic model is adapted to compute the similarity between a color region and the skin color. Both Haar-like features and Local Binary Pattern (LBP) features are utilized to build a cascaded classifier. The boosted classifier is implemented based on skin color emphasis to localize the face region from a color image. Based on our experiments, the proposed method shows good tolerance to face pose variation and complex background with significant improvements over classical boosting-based classifiers in terms of total error rate performance. 相似文献
994.
Pt-V2O5-WO3/TiO2 catalysts supported on SiC filter for NO reduction at low temperature 总被引:1,自引:0,他引:1
Joo-Hong Choi Jin-Hyun Kim Young-Cheoul Bak Rose Amal Jason Scott 《Korean Journal of Chemical Engineering》2005,22(6):844-851
The catalytic filter, V2O5-WO3-TiO2 supported on a ceramic filter, is known as a promising material for treating particulates and NO
x
simultaneously at optimum temperatures around 320°C. In order to improve its catalytic activity at low temperatures, the
effect of Pt addition on the catalytic filter has been investigated. Catalytic filters, Pt-V2O5-WO3-TiO2/SiC, were prepared by co-impregnation of Pt, V, and W precursors on TiO2 coated-SiC filter by vacuum aided-dip coating. The Pt-added catalytic filter shifted the optimum working temperature from
280–330°C (for the non Pt-impregnated filter) to 180–230°C, providing N
x
slip concentration less than 20 ppm for the treatment of 700 ppm NO at a face velocity of 2 cm/s with the same value over
the non Pt-added catalytic filters. The promotional effect following the addition of Pt is believed to result from electrical
modification of the catalyst maintaining a high electron transfer state. Ammonia oxidation was also observed to be dominant
above the optimal temperature for SCR. 相似文献
995.
Woon-Jae Lee Sang-Done Kim Byung-Ho Song 《Korean Journal of Chemical Engineering》2002,19(6):1091-1096
To produce low calorific value gas, Australian coal has been gasified with air and steam in a fluidized bed reactor (0.1 m-I.Dx1.6
m-high) at atmospheric pressure. The effects of fluidizing gas velocity (2–5 Uf/Umf), reaction temperature (750–900 °C), air/coal ratio (1.6-3.2), and steam/coal ratio (0.63–1.26) on gas composition, gas yield,
gas calorific value of the product gas and carbon conversion have been determined. The calorific value and yield of the product
gas, cold gas efficiency, and carbon conversion increase with increasing fluidization gas velocity and reaction temperature.
With increasing air/coal ratio, carbon conversion, cold gas efficiency and yield of the product gas increase, but the calorific
value of the product gas decreases. When steam/coal ratio is increased, cold gas efficiency, yield and calorific value of
the product gas increase, but carbon conversion is little changed. Unburned carbon fraction of cyclone fine decreases with
increasing fluidization gas velocity, reaction temperature and air/coal ratio, but is nearly constant with increasing steam/coal
ratio. Overall carbon conversion decreases with increasing fluidization velocity and air/ coal ratio, but increases with increasing
reaction temperature. The particle entrainment rate increases with increasing fluidization velocity, but decreases with increasing
reaction temperature.
This paper is dedicated to Professor Dong Sup Doh on the occasion of his retirement from Korea University. 相似文献
996.
Tae-Sung Kim Xiaofeng Li Sungwook Hong 《International journal of remote sensing》2014,35(11-12):3947-3965
The relationship between the modification of synthetic aperture radar (SAR) wind field and coastal upwelling was investigated using high-resolution wind fields from Advanced Land Observing Satellite (ALOS) Phased Array type L-band synthetic aperture radar (PALSAR) imagery and sea-surface temperature (SST) from National Oceanic and Atmospheric Administration/Advanced Very-High-Resolution Radiometer (NOAA/AVHRR) data. The retrieved SAR wind speeds seem to agree well with in situ buoy measurements with only a relatively small error of 0.7 m s?1. The SAR wind fields retrieved from the east coast of Korea in August 2007 revealed a spatial distinction between near and offshore regions. Low wind speeds of less than 3 m s?1 were associated with cold water regions with dominant coastal upwelling. Time series of in situ measurements of both wind speed and water temperature indicated that the upwelling was induced by the wind field. The low wind field from SAR was mainly induced by changes in atmospheric stability due to air–sea temperature differences. In addition, wind speed magnitude showed a positive correlation with the difference between SST and air temperature (R2 = 0.63). The dependence of viscosity of water on radar backscattering at the present upwelling region was negligible since SAR data showed a relatively large backscattering attenuation to an SST ratio of 1.2 dB °C?1. This study also addressed the important role of coastal upwelling on biological bloom under oligotrophic environments during summer. 相似文献
997.
Werten Paul J.L.; Carver John A.; Jaenicke Rainer; de Jong Wilfried W. 《Protein engineering, design & selection : PEDS》1996,9(11):1021-1028
ß-Crystallins are structural lens proteins with aconserved two-domain structure and variable N- and C-terminalextensions. These extensions are assumed to be involved in quaternaryinteractions within the ß-crystallin oligomers orwith other lens proteins. Therefore, the production of ßA3-and ßAl-crystallin from the single ßA3/A1mRNA by dual translation initiation is of interest. These crystallinsare identical, except that ßAl has a much shorterN-terminal extension than ßA3. This rare mechanismhas been conserved for over 250 million years during the evolutionof the ßA3/A1 gene, suggesting that the generationof different N-terminal extensions confers a selective advantage.We therefore compared the stability and association behaviourof recombinant ßA3- and ßAl-crystallin.Both proteins are equally stable in urea- and pH-induced denaturationexperiments. Gel filtration and analytical ultracentrifugationestablished that ßA3 and ßA1 both form homodimers.In the water-soluble proteins of bovine lens, ßA3and ßA1 are present in the same molecular weight fractions,indicating that they oligomerize equally with other ß-crystallins.1H-NMR spectroscopy showed that residues Met1 to Asn22 of theN-terminal extension of ßA3 have great flexibilityand are solvent exposed, excluding them from protein interactionsin the homodimer. These results indicate that the differentN-terminal extensions of ßA3 and ßA1 donot affect their homo- or heteromeric interactions. 相似文献
998.
Jeong-Ho Cho In-Kil Park Ho-Gi Kim Hoon-Taek Chung 《Journal of the American Ceramic Society》1997,80(6):1523-1534
Substituting Cd2+ ions into the A and B sites in a Pb(Ni1/3 Nb2/3 )O3 PbZrO3 PbTiO3 (PNNPZPT) ternary perovskite material made it possible to determine the effects of the Cd2+ ion substitution site on sintering behavior. The substitution site of the Cd2+ ion was identified by using X-ray photoelectron spectroscopy spectra. Although Cd2+ ions were substituted into the A and B sites in PNNPZPT, the Cd2+ ions preferred the A site over the B site. When Cd2+ ions replaced Pb2+ ions, a weight gain was observed during sintering. On the other hand, replacing Ni2 ions with Cd2+ ions promoted weight loss. Those weight changes indicated that Cd2+ ions change the bonding strength between the B-site cations and the oxygen of the octahedron in a perovskite structure. Density was influenced by the Cd2+ ion substitution site, and the A-site-doped compositions had higher densities than the B-site-doped compositions. 相似文献
999.
Racemicezo-brevicomin, racemic frontalin, and myrcene were released at two proportions (51400 and 111), each at three levels (1 ×, 10 ×, and 100 ×) in a ponderosa pine forest in central California. The 51400 mix was based on an estimate of the relative amounts released from a ponderosa pine under attack by the western pine beetle,Dendroctonus brevicomis. MoreD. brevicomis were trapped at a source of the three compounds released at 51400 than were trapped at a source released at 111, at all three levels, but this difference was statistically significant only at the 1 × and 10 × levels. Sex ratio of trapped beetles and distribution of catch at the source of attractant and 5 m away apparently did not differ between relative release rates.Coleoptera: Scolytidae.Trade names are mentioned solely for information. No endorsement by the U.S. Department of Agriculture is implied. 相似文献
1000.
Unsaturated polyester (UP)/montmorillonite (MMT) nanocomposite was prepared by using hydroxypropylacrylate (HPA) as a reactive diluent instead of conventional styrene monomer and the effect of polarity of reactive diluent on properties of nanocomposite was investigated. X‐ray and mechanical test data indicated that mixing for an extended period of time is essential to enhance the physical properties of nanocomposites in the UP/Cloisite 6A system. This was attributed to the high polarity of HPA that may disturb the preintercalation of UP resin into the galleries of MMT. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 238–242, 2004 相似文献