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101.
选用合适单体合成高反应活性聚酯树脂,介绍了树脂的合成工艺,以高亚氨基部分醚化氨基树脂为交联剂,自制二壬基二磺酸为催化剂,制成低温固化卷材涂料。所制备的涂料具有很好的耐候性和加工成型性能。讨论了影响涂料性能的因素。 相似文献
102.
对钙基CO2吸收剂的循环活性衰减进行了实验研究,考察了随着循环次数的增加,吸收剂的表面形态、吸收剂分子孔径及比表面积等微观结构的变化,分析了钙基CO2吸收剂循环活性衰减的原因。结果表明,随着循环次数的增加,吸收剂晶粒中的片状结构已经完全消失,取而代之的是正方体状的大晶粒,晶粒生长严重,大量空隙被封闭。而由此引起的吸收剂的比表面积的不断减小和孔容积的降低以及孔分布的改变,导致了吸收剂循环活性的衰减,吸收剂的循环转化率降低。 相似文献
103.
采用以低杂质沥青焦模拟石油焦和外掺杂的方式,研究硫杂质元素对焦反应性的影响,并通过XRD、SEM和EDS等检测手段探讨其作用机理。结果表明:在无其他杂质元素干扰的情况下,硫实际上是一种对焦的空气和CO2反应性都具有明显催化性的杂质元素。其催化作用可能是通过在焦的空气和CO2反应过程中分别引发有机硫→H2S→SO2→COS和单质硫(S x)→SO2和有机硫→H2S→COS→S x→C2S→COS两组可部分循环并具有增加碳耗和增大焦比表面积作用的反应体系来实现的。 相似文献
104.
Yashbir Singh Shivay Dinesh Kumar Rajendra Prasad 《Nutrient Cycling in Agroecosystems》2008,81(3):229-243
Zinc deficiency is prevalent worldwide and is a barrier in achieving yield targets in crops. It is also now recognized as
a leading risk factor for disease in humans in developing countries. Generally, soil application of 5–17 kg Zn ha−1 y−1 (25–85 kg zinc sulphate heptahydrate ha−1 y−1) or more is recommended for rice. However, in the developing rice-growing countries of Asia, zinc sulphate of desired quality
is not readily available and is also quite expensive, and the farmers generally fail to apply Zn, resulting in crop yield
loss in rice. Availability of zinc-enriched urea (ZEU) makes possible not only the availability of quality zinc, but also
assures its application. Therefore, field experiments were conducted for two consecutive years at the research farm of Indian
Agricultural Research Institute, New Delhi, India, during rainy (rice) and winter (wheat) seasons of 2004–2006 on a sandy
clay-loam soil to study the effect of various concentrations of zinc enrichment of urea on productivity, zinc concentrations,
its uptake and use indices of aromatic rice–wheat cropping system. Eight treatments comprising prilled urea (PU) and 0.5,
1.0, 1.5, 2.0, 2.5, 3.0 and 3.5% zinc-enriched urea, replicated three times, were compared in a randomized block design. The
enrichment of PU was done through zinc oxide containing 80% zinc. The results of this study revealed that the zinc-enriched
urea (ZEU) had a significant effect on growth, yield attributes and yields of aromatic rice. Highest values for all these
attributes and yields were recorded at the highest enrichment (3.5%) of the PU with zinc. The highest zinc concentration and
uptake in rice grain and straw were also significantly higher with the highest level (3.5%) of zinc enrichment. The highest
total zinc uptake recorded was 1,168 and 1,353 g ha−1, during 2004 and 2005, respectively, with 3.5% ZEU. However, a major increase in grain yield of rice was recorded up to 1.0%
zinc enrichment. The residual effect of zinc-enriched urea on succeeding wheat yield and zinc uptake was significant only
at a higher level of zinc-enriched urea and only in the second year of study. Overall, 1.0% zinc-enriched urea recorded significantly
higher productivity and zinc uptake over PU in the rice–wheat cropping system and is recommended for Delhi and adjoining areas.
The recommendation is also made keeping in view the fact that with increased levels of zinc enrichment of urea, the partial
factor productivity, agronomic efficiency, apparent recovery and physiological efficiency of applied zinc in a rice–wheat
system decreased significantly. Considering all the economic parameters (benefit, benefit:cost ratio, IR gained IR−1 invested in zinc), 1.0% ZEU proved the most economic source for aromatic rice–wheat cropping system and therefore is recommended
for rice–wheat cropping system in Delhi and adjoining areas of north India. 相似文献
105.
Hafida Harrar‐Ferfera 《应用聚合物科学杂志》2008,107(6):3963-3973
Copolymerizations of methyl methacrylate (MMA) with 4‐vinylpyridine (4VP) were performed from different monomer feed ratios in 1,4‐dioxan at 30°C under free radical initiation experimental conditions, using Ni(II)α‐Benzoinoxime complex as initiator. The obtained copolymers (PMMA4VP) were examined by FTIR and 1H NMR spectroscopies. The composition of these copolymers was calculated, using 1H NMR spectra and elemental analysis. Monomer reactivity ratios were estimated from Fineman–Ross (FR, rm = 0.550, rv = 1.165) and Kelen–Tudos (KT, rm = 0.559, rv = 1.286) linearization methods, as well as nonlinear error in variables model (EVM) method using the RREVM computer program (RREVM, rm = 0.559, rv = 1.264). These values suggest that MMA‐4VP pair copolymerizes randomly. 1H NMR spectra provide information about the stereochemistry of the copolymers in terms of sequence distributions and configurations. These results showed that the age of the Ni complex has an impact not only on its activity towards polymerization reactions but also on the features of the corresponding copolymers, whereas the chemical composition was insensitive to this prominent factor. The mechanism of MMA‐4VP copolymerization is consistent with a radical process as supported by microstructure and molecular weight distribution studies. Thermal behaviours of these copolymers were investigated by differential scanning calorimetry and thermogravimetric analysis. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献
106.
The decomposition of methane, its conversion into higher hydrocarbons and the reaction between CH4 and CO2 have been investigated on Rh/ZSM-5 in a fixed bed continuous-flow reactor. Independently of the temperature at 523–973 K,
the decomposition of methane gave hydrogen, surface carbon and a small amount of ethane: ethylene and benzene were not detected.
The reactivity of surface carbon formed at different temperatures has been examined toward H2, O2 and CO2. The carbon exhibited less reactivity toward CO2. The reaction between CH4 and CO2 occurred rapidly above 673 K to give CO and H2 with a ratio of 1.3–1.6. Very little carbon was deposited during the reaction. It is concluded that the facile reactions
between CHx and CO2 are responsible for the lack of carbon deposition. However, a significant amount of carbon deposition and the deactivation
of the catalyst occurred when more than 4–5% of ethane was added to the reacting gas mixture. The extent of deactivation can
be decreased by using a large excess of CO2.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
107.
Döne Demirgöz Rodrigo Navarro Mónica Pérez Helmut Reinecke Alberto Gallardo 《应用聚合物科学杂志》2010,115(2):896-900
2‐Hydroxyethylmethacrylate (HEMA) and acrylamide (AA) have been copolymerized via free radical mechanism, in the presence of 5 mol % of four different crosslinker systems, the symmetric ethylenglycoldimethacrylate (EGDMA), bisacrylamide (BIS), a mixture of EGDMA and BIS, and the asymmetric acrylamideethylenmethacrylate (METAA). The polymerizations have been monitored with a rheometer, exhibiting the gel obtained with the asymmetric METAA, an elastic modulus that is dramatically increased compared with those of the gels prepared with the other three crosslinker systems. A kinetic analysis using the terminal model has been used to build probabilistic surfaces that give information about how the crosslinker is incorporated into the network. This analysis shows a high dissimilarity between the reactions using the asymmetric and the mixture of symmetric crosslinkers, what has been correlated to the difference in modulus. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
108.
粉煤灰和炉底渣均为燃煤发电过程中产生的固体废弃物,但两者的反应活性有所区别。研究结果表明,炉底渣的玻璃相含量以及活性SiO2、Al2O3含量均高于粉煤灰,在蒸压条件下炉底渣的反应活性优于粉煤灰,有利于生成更多的水化产物。利用炉底渣部分或全部取代粉煤灰制备蒸压硅酸盐制品,有利于提高制品的强度。 相似文献
109.
Several toxicological indices currently proposed (inter)nationally to aid decision-making tasks in effluent control were compared. To evaluate effluent ranking differences between the indices an inversion distance as a similarity measure was proposed. The major factor influencing effluent ranking were found to be a composition of test-battery. Differences in mathematical operator of the indices such as, e.g. arithmetic mean (used in averaging indices) or maximum one (used in an approach of the most sensitive test in a battery), affect the ranking similarity noticeably lesser than the modification of the percentage effect level of the measurement endpoints. Effluent and/or river flow parameters incorporated into the indices substantially modify ranking results of the effluent set. For the analysis, the toxicological information on 23 effluents from municipal wastewater treatment plants operating in cities and small towns of Lithuania as well as test-battery data on industrial effluents published elsewhere were used. It seems that the general statements achieved in the current study can be applied to any set of effluents. 相似文献
110.
In this study, the decomposition conditions of limestone particles (0.25-0.50 mm) for CO2 capture in a steam dilution atmosphere (20-100% steam in CO2) were investigated by using a continuously operating fluidized bed reactor. The results show that the decomposition conversion of limestone increased with the steam dilution percentage in the CO2 supply gas. At a bed temperature of 920 °C, the conversions were 72% without steam dilution and 98% with 60% steam dilution. The conversion was 99% with 100% steam dilution at 850 °C of the bed temperature. Steam dilution can decrease not only the decomposition temperature of limestone, but also the residence time required for nearly complete decomposition of CaCO3. The hydration and carbonation reactivities of the CaO produced were also tested and the results show that both the reactivities increased with the steam dilution percentage for decomposing limestone. 相似文献