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91.
92.
Gaussian models without intermittency are extensively used in estimating the effect of turbulence, but it also brings some puzzles, for example the observed pulse shape that disagrees with the result of the standard theory of interstellar scintillations. Indeed the property of intermittency is inherent in turbulence, i.e., all the quantities that characterize it suffer from strong fluctuations. So it is necessary to consider turbulent intermittency in manyapplications. In this paper we propose a non-Gaussian phase screen, which obeys log-Poisson statistics, and also offers the corresponding point spread function (PSF). These results describe that intermittency leads to the more extent and different directional distribution of PSF. Theoretical analysis is made under the hypothesis of the phase difference satisfying log-Poissonstatistics, and the average point spread function, which accord qualitatively with the result of the above generated phase screen, is derived. 相似文献
93.
Robustness Screen in Enantioselective Catalysis Enabled Generation of Enantioenriched Heterocyclic Scaffolds in One Pot 下载免费PDF全文
Pradip N. Bagle Valmik S. Shinde Nitin T. Patil 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(9):3580-3584
Enantioselective catalysis has emerged as a powerful synthetic paradigm and has accelerated the development of new methods to make diverse chiral molecules. Generally, these reactions are very sensitive to the steric and electronic environment present in the catalyst as well as the substrates. With this scenario, the presence of an additional component in the reaction mixture is expected to add complexity in achieving the enantioselective variants. Herein, we report that various enantioenriched molecules could be obtained from multiple starting materials in one pot. The reaction of aminoaromatics A with alkynols B1, B2, B3…?Bn with a AuI/chiral Brønsted acid catalyst afforded AB1*, AB2*, AB3*…ABn*; while, the reaction of alkynols B with aminoaromatics A1, A2, A3…An under the same reaction conditions gave A1B*, A2B*, A3B*…AnB * . 相似文献
94.
?????????????????????? 总被引:4,自引:0,他引:4
通过对惯性振动筛工作原理和噪声测试结果的分析,认为来自激振器的高频干扰力是引起振动筛高噪声的根本原因之一,在此基础上提出了用双质体结构降低振动筛噪声的新措施,说明该结构的降噪原理,并利用试验结果验证了该方法的有效性. 相似文献
95.
石油钻机盘式刹车副材料选配的实验研究 总被引:5,自引:2,他引:5
在 MMW- 1型摩擦磨损试验机上 ,通过变温摩擦磨损特性试验 ,对优选出的 2种刹车盘表面堆焊材料和研制出的 2种刹车块材料进行了选配 ,并对各刹车副的摩擦学性能进行了分析与评价 .结果表明 ,摩擦偶件对刹车副材料的摩擦学性能有一定的影响 ,因此在进行材料的选配试验时应考虑偶件的匹配问题 .优选出的 2种表面堆焊材料与所研制的 2种刹车块材料组成摩擦副时具有较高的平均摩擦系数和热摩擦系数以及优良的高温耐磨性能 ,其中第二种表面堆焊材料与所研制的第二种无石棉刹车块材料组成摩擦副时的摩擦学性能指标最优 ,可以作为选配出的最优刹车副材料 相似文献
96.
97.
Malaria continues to affect millions of people annually. With the rise of drug resistant strains, the need for alternative treatments has become increasingly urgent. Recently, PfUCHL3 was identified as an essential deubiquitinating enzyme. The increasing number of drug target structures being solved has increased the feasibility of utilizing a structural comparative approach to identifying novel inhibitors. Using AutoDock Vina, we recently screened the NCI library of about 320,000 compounds against the crystal structure of PfUCHL3. The top hits were subsequently screened against its human ortholog UCHL3 as to identify compounds that could specifically target the PfUCHL3 over its human counterpart. This method was used to identify small molecule inhibitors that can preferentially inhibit the parasitic enzyme. Several compounds were identified that demonstrated significant binding affinity preference for the malaria target over the human enzyme. Two of these compounds demonstrated ng/mL activity. 相似文献
98.
A Highly Sensitive and Selective Enzymatic Biosensor Based on Direct Electrochemistry of Hemoglobin at Zinc Oxide Nanoparticles Modified Activated Screen Printed Carbon Electrode 下载免费PDF全文
Selvakumar Palanisamy Chelladurai Karuppiah Shen‐Ming Chen Prakash Periakaruppan 《Electroanalysis》2014,26(9):1984-1993
A sensitive enzymatic biosensor has been developed for the detection of hydrogen peroxide (H2O2), nitrite ( ) and trichloroacetic acid (TCA) by using hemoglobin (Hb) immobilized on activated screen printed carbon electrode (ASPCE) and zinc oxide (ZnO) composite. A pair of well defined redox peaks is observed with a heterogeneous electron transfer rate constant (Ks) of 5.27 s?1 for Hb at ASPCE/ZnO. The biosensor exhibits the detection of H2O2, TCA and in the concentration range of 0.5–129.5 µmol L?1, 2.5–72.5 mmol L?1 and 0.2–674 µmol L?1 with the detection limit of 0.083 µmol L?1, 0.12 mmol L?1 and 0.069 µmol L?1, respectively. 相似文献
99.
Screen printing is a promising technology because of its simplicity, low-cost, high reproducibility, and efficiency in large-scale production. In this work, a cobalt-based phosphate sensor was successfully fabricated using the screen printing technology for the determination of phosphate concentration in the aqueous solution. The disposable sensor consists of a fully integrated cobalt(Co) electrode, which is a layer of carbon conductive ink(C) physically doped with Co powder, and Ag/AgCl reference electrode. The SEM images show that the morphology of the Co electrode changes after exposure to the phosphate solution, indicating that the expendable reaction exists during the measurement. At the Co/C ratio of 1:99, the cobalt-based phosphate sensor shows phosphate-selective potential response in the range of 10-4 to 10-1 mol/L, yielding a detection limit of 1×10-5 mol/L and a slope of over 30 mV/decade in acidic solution(pH 4.5) for H2PO4-. The proposed screen-printed sensor also exhibited significant reproducibility with a small repeated sensing deviation(i.e., relative standard deviation(R.S.D.) of 0.5%) on a single sensor and a small electrode-to-electrode deviation(i.e., R.S.D. 3.2%). The recovery study of H2PO4- in real wastewater samples gave values from 95.4% to 101.8%, confirming its application potential in the measurement of phosphate in real samples. Apart from its high selectivity, sensitivity, and stability comparable with a conventional bulk Co-wire electrode, the proposed phosphate sensor still yields many other advantages, such as low price, compactness, ease of use, and the possibility of integration with other analytical devices such as flow injection analysis. 相似文献
100.