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The use of directly fired heat engines, i. e. diesel and gas turbine engines, is likely to grow in the future. However, economic requirements will necessitate the development of highly efficient engines that operate at high temperatures and utilize low-grade fuels. An increase of combustion gas temperature and the utilization of low-grade fuels contaminated with, amongst others, sulphur and vanadium, may be accomplished by careful selection of the materials, e.g. by applying corrosion-resistant coatings on heatresistant alloys. The main purpose of the present work has been to test various coatingsubstrate combinations in a highly corrosive environment. The comparison of various coating techniques, e.g. electron beam physical vapour deposition (EB-PVD), air plasma spraying (APS), and low pressure plasma spraying/vacuum plasma spraying (LPPS/VPS), has been emphasized. 相似文献
74.
In this paper, problems that occur when working with welds formed of high-alloy steels to restore their passive layers, damaged as a result of temperature impact, are discussed. Particular attention was paid to the procedures concerning aggressive etching agents during and after completion of the passivation processes (waste neutralization and utilization). 相似文献
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The treatment of many diseases may require drugs that are capable to attack multiple targets simultaneously. Obviously, the virtual screening of multi-target drug candidates is much more time consuming compared to the single-target case. This, in particular, concerns the last step of virtual screening where the binding free energy is computed by conventional molecular dynamics simulation. To overcome this difficulty we propose a simple protocol which is relied on the fast steered molecular dynamics simulation and on available experimental data on binding affinity of reference ligand to a given target. Namely, first we compute non-equilibrium works generated during pulling ligands from the binding site using the steered molecular dynamics method. Then as top leads we choose only those compounds that have the non-equilibrium work larger than that of a reference compound for which the binding free energy has been already known from experiment.Despite many efforts no cures for AD (Alzheimer’s disease) have been found. One of possible reasons for this failure is that drug candidates were developed for a single target, while there are exist many possible pathways to AD. Applying our new protocol to five targets including amyloid beta fibril, peroxisome proliferator-activated receptor γ, retinoic X receptor α, β- and γ-secretases, we have found two potential drugs (CID 16040294 and CID 9998128) for AD from the large PubChem database. We have also shown that these two ligands can interfere with the activity of popular Acetylcholinesterase target through strong binding towards it. 相似文献
77.
无皂硅丙胶乳表面施胶剂的制备及对纸张的增强作用 总被引:1,自引:0,他引:1
以γ-甲基丙烯酰氧丙基三甲氧基硅烷(KH570)作自交联单体,聚乙烯醇(PVA)为高分子胶体稳定剂,苯乙烯(St)、丙烯酸丁酯(BA)、甲基丙烯酸(MAA)为单体采用无皂种子聚合制备了稳定性好、性能优异的无皂硅丙乳液表面施胶剂,并优化了合成工艺条件。结果表明,当w(MAA)=2%~3%,软硬单体比例n(BA)/n(St)=2~2.5,w(PVA)=10%~15%,w(KH570)=5%时,无皂硅丙乳液表面施胶剂具有优异的施胶效果;以质量分数为1.0%的聚合物乳液进行表面施胶时,纸张施胶度可达14.5 s,表面强度达3.69 m/s,耐折度3300次。 相似文献
78.
Jun ZOU Lianhan ZHANG Jun XU Shengming ZHOU 《材料科学技术学报》2006,22(4):491-494
Large-sized (~2 inch, 50.8 mm) γ-LiAlO2 single crystal has been grown by conventional Czochralski (Cz) method, but the crystal has a milky, dendriform center. The samples taken from transparent and milky parts were ground and examined by X-ray diffraction. All diffraction peaks could be indexed in γ-LiAlO2. The crystal quality was characterized by X-ray rocking curve. The full-width at half-maximum (FWHM) values are 116.9 and 132.0 arcsec for transparent and milky parts, respectively. The vapor transport equilibrium (VTE) technique was introduced to modify the crystal quality. After 1000℃/48 h, 1100℃/48 h, 1200℃/48 h VTE processes, the FWHM values dropped to 44.2 and 55.2 arcsec for transparent and milky part, respectively. The optical transmission of transparent part was greatly enhanced from 85% to 90%, and transmission of milky part from 75% to 80% in the range of 190~1900 nm at room temperature. When the VTE temperature was raised to 1300℃, the sample cracked and FWHM values of transparent and milky parts were increased to 55.2 and 80.9 arcsec, respectively. By combining Cz technique with VTE technique, large-sized and high quality γ-LiAlO2 crystal can be obtained. 相似文献
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The morphological, thermal and pasting properties of starch separated from potatoes of three varieties (Kufri Chandramukhi, Kufri Jyoti and Kufri Chipsona-2), treated either with CIPC (isopropyl N-(3 chlorophenyl) carbamate) or γ-irradiation (Co60, 0.1 and 0.5 kGy) and subsequently stored at 8, 12 and 16 °C for 90 days, were studied. Scanning electron microscopy (SEM) showed the presence of oval and irregular shaped starch granules with a diameter range of 15–16 μm. Mean granule size of starch separated from potatoes stored at 12 °C ranged from 18–25 μm and irradiation treatment resulted in an increase in the proportion of small size granules. The irradiation of potatoes with 0.5 kGy resulted in starch with significantly lower peak-, trough- and breakdown-viscosity as compared to starch from potatoes treated with either CIPC or 0.1 kGy irradiation. The irradiation of potatoes with 0.5 kGy caused a significant increase in setback and pasting temperature. Pasting temperature of starch was observed to vary with the storage temperature. Starch separated from potatoes stored at higher temperature showed lower pasting temperature and vice versa. The starch from potatoes stored at 8 °C showed higher peak-, trough- and breakdown-viscosity and lower setback. Peak viscosity increased and swelling volume decreased with increase in storage temperature. FTIR spectra showed that the starch from irradiated potatoes displayed a significant decrease in the intensity of the C–H stretch region between 2800 and 3000 cm−1, which was observed to be irradiation dose-dependent, and higher with 0.5 than 0.1 kGy. However, a slight broadening of O–H stretch (3000–3600 cm−1) in starches from irradiated potatoes was observed. The spectral changes caused by γ-irradiation were apparent in the O–H stretch (3000–3600 cm−1), C–H stretch (2800–3000 cm−1) and bending mode of water (1600–1800 cm−1). 相似文献