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41.
This paper considers the wave loads on large monolithic offshore structures. The second order wave force formulae developed by Rahman and Heaps, applicable to large circular cylinders in waves, are extended to evaluate the overturning moments on large circular cylinders. The theory is then applied to square section caissons in waves, to predict the wave loads on these structures. These calculations are performed using the exact form of the second order velocity potential, φ2, with arbitrary wave number, k2, and the approximate form of φ2, with twice the value of the wave number of the first order velocity potential. The second order analytical predictions are compared with available experimental data for various ranges of wave parameters for both circular and square caissons in large amplitude waves.  相似文献   
42.
Let us denote byΛ n, 1 the supremum of (maxz∥=1p′ n (z)∥)/ (maxz∥=1p n (z)∥) taken over all polynomialsp n of degree at mostn having a zero on the unit circle {z ∈ C∶∥z∥=1}. We show that Λn.1=n-(π 2/16)(1/n)+O(1/n 2.  相似文献   
43.
High resolution gamma-ray spectra have been measured from the27Al (p,γ)28Si reaction for the resonances atE p=2·482, 2·511 and 2·735 MeV at ϑ pγ=0°, 30°, 55° and 90° using a Ge (Li) gamma spectrometer. From the spectra and the angular distributions the properties of the resonance states have been obtained. These states are the isobaric analogues of the levels at 4·69, 4·75 and 4·93MeV levels respectively in the parent nucleus A28l.  相似文献   
44.
An efficient synthesis of diaryl ethers by the copper-catalyzed arylation of phenols with a variety of aryl iodide susing KF/Al2O3 as a suitable base and CuI and 1,3 diphenyl-1,3 propandione as the catalyst is described.  相似文献   
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Riju Khandaker  M.  Kamruzzaman  M.  Afrose  R.  Rahman  M.  Khan  M. K. R.  Liton  M. N. H.  Helal  M. A.  Anam  T. K.  Rahman  M. M. 《Crystallography Reports》2020,65(6):968-979
Crystallography Reports - Transition metals doped FeS2 thin films are promising materials for optoelectronics, energy saving and storage applications. This is a first time report on the...  相似文献   
48.
 A sensitive and fairly selective quenchofluorimetric method for the determination of mercury ultra-trace with murexide (ammonium purpurate) has been developed. The method is based on the instantaneous quenching action of the metal-ion upon the native fluorescence of murexide [λex(max) = 360 nm; λem(max) = 445 nm] in the optimum pH range of 5.8 to 6.6 at room temperature (25±0.5) °C. The fluorescence quenching is collinear in the range of 5 μg/L to 100 μg/L mercury. The developed method is very precise and accurate (RSD = 2.2% for 11 determination of 50 μg/L Hg(II). Large excesses of more than 50 cations, anions and complexing agents were found to have no interference. The developed method was successfully tested over synthetic mixtures of various compositions, certified reference materials and factory effluents. Received November 16, 1999. Revision March 30, 2001.  相似文献   
49.
Organic perovskite has potential to replace organic dye as light absorber in solar cell since it possesses better optical absorption in visible region than organic dye. This work is concerned with the investigation of the influence of CH3NH3PbI3 perovskite dipping time on the performance of perovskite-sensitized solar cell (PSSC). The effect of the dipping time on the morphology and photoluminescence of the sample has also been investigated. It was found that the device achieved a power conversion efficiency (PCE) as high as 5.57 ± 0.4% at the optimum dipping time of 4 h. The highest PCE is due to the highest IPCE, lowest Rct and the longest carrier lifetime (τ).  相似文献   
50.
Obesity and diabetes are the most demanding health problems today, and their prevalence, as well as comorbidities, is on the rise all over the world. As time goes on, both are becoming big issues that have a big impact on people’s lives. Diabetes is a metabolic and endocrine illness set apart by hyperglycemia and glucose narrow-mindedness because of insulin opposition. Heftiness is a typical, complex, and developing overall wellbeing worry that has for quite some time been connected to significant medical issues in individuals, all things considered. Because of the wide variety and low adverse effects, herbal products are an important hotspot for drug development. Synthetic compounds are not structurally diverse and lack drug-likeness properties. Thus, it is basic to keep on exploring herbal products as possible wellsprings of novel drugs. We conducted this review of the literature by searching Scopus, Science Direct, Elsevier, PubMed, and Web of Science databases. From 1990 until October 2021, research reports, review articles, and original research articles in English are presented. It provides top to bottom data and an examination of plant-inferred compounds that might be utilized against heftiness or potentially hostile to diabetes treatments. Our expanded comprehension of the systems of activity of phytogenic compounds, as an extra examination, could prompt the advancement of remedial methodologies for metabolic diseases. In clinical trials, a huge number of these food kinds or restorative plants, as well as their bioactive compounds, have been shown to be beneficial in the treatment of obesity.  相似文献   
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