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201.
达妮莎 《数码设计:surface》2011,(3):281-283
象征(Symbol)源于古希腊语,最初是指一块书板的两半,两人各取半块。后来指参与神秘活动的认证通行证。象征,指借具体有形之事物以表示某种无形之抽象概念或思想感情。当"象征"用作动词时,即为用具体事物表示抽象概念;当"象征"用作名词时,即表达抽象概念的具体事物。在蒙古族民间手工艺中,常以象征作为手法,表现其内容与形式,思想观念与外在特征的联系,这在蒙古人的宗教文化中尤为突出。 相似文献
202.
The thermodynamic analysis of steam reforming of methanol without and with fractional removal of H2 and CO2 in adsorption, membrane and adsorption-membrane hybrid reactor systems to produce fuel cell grade H2 with minimal carbon formation is investigated. The results indicate that the removal of undesired CO2 by CO2 adsorbent is most effective process for the production of high purity H2 than H2 removal by membrane. However, the membrane is effective only above 30% H2 removal. It is possible to obtain H2 yield of 2.6 with negligibly small amount of CO and carbon formation at T = 405 K, P = 1 atm, 80% removal of CO2 and 100% methanol conversion. Identical results are achieved even at lower temperature of 345 K in adsorption-membrane hybrid reactor system at 80% removal of H2 and CO2. Thus high grade H2 can be produced by single step process and further processing to reduce CO by PROX reactor is not necessary. 相似文献
203.
Abstract
NiFe2O4 nanoparticles stabilized by porous silica shells (NiFe2O4@SiO2) were prepared using a one-pot synthesis and characterized for their physical and chemical stability in severe environments, representative of those encountered in industrial catalytic reactors. The SiO2 shell is porous, allowing transport of gases to and from the metal core. The shell also stabilizes NiFe2O4 at the nanoparticle surface: NiFe2O4@SiO2 annealed at temperatures through 973 K displays evidence of surface Ni, as verified by H2 TPD analyses. At 1,173 K, hematite forms at the surface of the metallic cores of the NiFe2O4@SiO2 nanoparticles and surface Ni is no longer observed. Without the silica shell, however, even mild reduction (at 773 K) can draw Fe to the surface and eliminate surface Ni sites. 相似文献204.
Kamal A Sultana F Ramaiah MJ Srikanth YV Viswanath A Kishor C Sharma P Pushpavalli SN Addlagatta A Pal-Bhadra M 《ChemMedChem》2012,7(2):292-300
A new series of 3‐substituted 2‐phenylimidazo[2,1‐b]benzothiazoles ( 3 a – h ) were synthesized by C‐arylation of 2‐arylimidazo[2,1‐b]benzothiazoles using palladium acetate as catalyst, and the resulting compounds were evaluated for their anticancer activity. Compounds 3 a , 3 e , and 3 h exhibited good antiproliferative activity, with GI50 values in the range of 0.19–83.1 μM . Compound 3 h showed potent anticancer efficacy against 60 human cancer cell lines, with a mean GI50 value of 0.88 μM . This compound also induced cell‐cycle arrest in the G2/M phase and inhibited tubulin polymerization followed by activation of caspase‐3 and apoptosis. A high‐throughput tubulin polymerization assay showed that the level of inhibition for compound 3 h is similar to that of combretastatin A‐4. Molecular modeling studies provided a molecular basis for the favorable binding of compounds 3 a , 3 e , and 3 h to the colchicine binding pocket of tubulin. 相似文献
205.
Parveen Sultana Sukhen Das Alakananda Bhattacharya Ruma Basu Papiya Nandy 《Materials science & engineering. C, Materials for biological applications》2012,32(6):1358-1365
The increasing accumulation of fly ash from thermal power plants poses a major problem to the environment. The present work reflects the novel utilization of this profusely available industrial waste in the form of an antibacterial hard ceramic material by treating fly ash with ferric oxide (Fe2O3) and titania (TiO2) during sintering process at 1600 °C. The developed material shows more than 90% bacterial reduction against both Gram-positive and Gram-negative bacteria. The mechanism of their antibacterial action was studied by transmission electron microscopy (TEM) image analysis of the bacterial cross-section. The developed ceramic material acquires hardness due to the enhancement of the natural mullite content in the matrix. The mullite content and the crystallinity of mullite have shown their increasing trend with increasing concentration of the metal oxide during sintering process. A maximum of ~ 37% increase in mullite was obtained for 7% w/w Fe2O3 and TiO2. Metal oxide lowered the activation energy of the reaction and enhanced the reaction rate of alumina (Al2O3)–silica (SiO2) to form mullite which increases the hardness. The study highlights novel utilization of fly ash as a hard ceramic antibacterial product (bioceramics) for both structural and hygiene applications in an eco-friendly way. 相似文献
206.
Public or stakeholder participation in planning and management of natural resources is now widely practiced, but means different
things in different contexts. Examples of recent participation in floodplain management in Bangladesh and England are reviewed
in the national policy context. Participation in floodplain planning in England is influenced by a centralised state and European
Union directives. The Ribble process tried to involve a wide range of stakeholders, but is limited to the development of plans
through consultations structured and managed by the Environment Agency. By comparison in Bangladesh local participatory planning
with different stakeholders has articulated their separate needs and suggestions, and brought them together to search for
consensus. Decision making and responsibilities over flood management infrastructure and floodplain resources have been devolved
to community organisations and co-management committees formed through the participation process. The Bangladesh examples
show how participation can be made more accessible to people through events that have real local meaning since representatives
gain power to raise funds and implement decisions for the benefit of their stakeholder constituencies. In Bangladesh rural
populations dependent on floodplain resources have an incentive to participate in implementation and oversight of management
decisions and actions that is lacking for most urban people in England. However, the merits of building up from local participation
to catchment planning and of linking floodplain specific participatory institutions with existing local government are lessons
that could be adapted from Bangladesh to England. 相似文献
207.
Shahzeb Ullah Khan Muhammad Zafar Riaz Ullah Abdelaaty A. Shahat Mushtaq Ahmad Shazia Sultana Khafsa Malik 《Microscopy research and technique》2021,84(1):42-55
In this study we have discussed pollen morphology of 14 mimosaceous species belonging to five genera by using light microscopy (LM) and scanning electron microscopy (SEM). The palynological features of species were determined by both qualitative and quantitative characters. The qualitative characters include pollen shape, colpi arrangement, and exine sculpturing. Oblate spheroidal shaped pollens were noted in Albizia procera, Albizia lebbeck, Acacia tortilis, Acacia ampliceps, and Acacia modesta, subprolate shaped pollen in Leucaena leucocephala, Prosopis julifera, and Acacia nilotica, prolate pollen in Acacia farnesiana and Prosopis glandulosa while spheroidal, sub spheroidal and sub oblate pollen grains were observed in Acacia catechu, Mimosa himalayana, Prosopis cineraria, respectively. Sparsely foveolate, reticulate, scabrate, and scrobiclate exine sculpturing were observed. Colpi with sunken ornamentation were seen in P. cineraria, P. glandulosa, P. juliflora, and L. leucocephala while colpi were absent in rest of the studied species. The quantitative characters were statistically studied using SPSS software. The current study gives important morpho‐palynological characters for identifying and validation of close related and similar taxa which will aid to the phylogenetic analysis of Mimosaceae family. 相似文献
208.
T Vanderah AE Takemori M Sultana PS Portoghese HI Mosberg VJ Hruby RC Haaseth TO Matsunaga F Porreca 《Canadian Metallurgical Quarterly》1994,252(2):133-137
A total of 78 patients with superficial bladder carcinoma were prospectively randomized to two groups following complete transurethral resection (TUR). Each received 12 intravesical instillations of 10(7) units interferon A or 120 mg BCG Connaught for 1 year starting 6 weeks post-TUR. After a mean observation period of 24 (13-31) months in the BCG and 25 (6-32) months in the IFN group 5/32 (15.6%) recurrences in the BCG versus 21/35 (60%) in the IFN group were observed (P = 0.0003). In the IFN group 18.4% of the patients had dysuria and 2.6% fever; in the BCG group 35% had fever, 60% cystitis, 1 patient granulomatous epididimoorchitis and 1 patient pneumonitis with granulomatous prostatitis. With our instillation regimen interferon A had few side effects but also no prophylactic effect, whereas BCG had tolerable-seldom severe--side effects and was very effective in preventing recurrences. Perhaps IFN should be given earlier after TUR and in a higher dosage. 相似文献
209.
A bacterial strain AS1 belonging to the genus Ochrobactrum, was isolated from an enriched phenol-activated sludge in Egypt. This strain grew aerobically on phenol as the sole carbon source using the meta-cleavage pathway at high phenol-degrading rates compared with those in a previous report. 相似文献
210.
Pressure swing NOx adsorption-desorption cycles were performed in the temperature range 200-350 degrees C using a fixed adsorbent bed of compressed Na-Y pellets and using a honeycomb coated with Na-Y powder. The experiments were performed using a synthetic gas mixture mimicking exhaust from a lean burn internal combustion engine. Na-Y zeolite coadsorbs NO and NO2 as N2O3, which in the regeneration were displaced by competitively adsorbed water molecules from a hydrated air stream. The performance of the fixed bed in these NOx adsorption and displacement desorption processes were modeled with a one-dimensional model. The kinetic and thermodynamic parameters from the fixed bed model were implemented in a model for the operation of the monolith. The experimental adsorption and desorption NOx concentration profiles in the monolith were reasonably well reproduced by the model. The water content of the flushing stream and the stripping gas flow rate are key process parameters. Technically, both parameters can be optimized in a valveless system with rotating honeycomb adsorbent comprising a NOx adsorption, a water injection and a NOx evacuation section. 相似文献