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71.
α-Thiocarbonylthioformamide is a stable and almost unexplored class of compounds1 which attracts us to study their properties and reactions. According to literature three-valenced phosphorus compound is easy to react with thiirane2 and thiocarbonate3 to form C=C double bond. So we want to explore the reaction of α-thiocarbonylthioformamide with three-valenced phosphorus compound. In initial experiment, we explored the reaction of α-thiobenzoylthioformmorpholine (1a) with trimethyl phosphite in dry diethyl ether at room temperature. 相似文献
72.
2,2-Dimethyl-3-(2,2-dichloroethecyclopropanecarbonylchloride(hereafterreferredtoaspermethricacidchloride)isausefulintermediateforthepreparationofsomesyntheticpyrethroids,suchaspermethrinandcypermethrin.Permethricacidchloridehasageometricalisomericpair,oiLyandtrans,owingtoitscyclopropanering.Itisknownthat,ingeneral,theestersderivedfromtheirans-isomerarelesstoxictomammalsthanthosederivedfromtheets-isomerl--3.Thepermethricacidproducedindustriallyisalwaysinformsofmixturesoftrans-andets-isomers.Ac… 相似文献
73.
74.
In this paper, we establish a blow‐up criterion of strong solutions for 3D viscous‐resistive compressible magnetohydrodynamic equations, which depends only on and . Our result improves the previous criterion in Lu's paper (Journal of Mathematical Analysis and Applications 2011; 379: 425–438.) for compressible magnetohydrodynamic equations by removing a stringent condition on the viscous coefficients μ > 4λ. In addition, initial vacuum states are also allowed in our cases. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
75.
CHEN Mingtao 《偏微分方程(英文版)》2011,(2):158-164
In this paper, we consider the viscous, micropolar, compressible flow in one dimension. We give the proof of existence and uniqueness of strong solutions for the initial boundary problem that vacuum can be allowed initially. 相似文献
76.
Yongbing Song Run Jiang Zheng Wang Lang Wang Yuhua Yin Baohui Li An‐Chang Shi 《Macromolecular theory and simulations》2016,25(6):559-570
The self‐assembled morphologies of cyclic amphiphiles, which are composed of a long hydrophobic block and a short hydrophilic block, in selective solutions are studied by using a simulated annealing method. The morphological dependence of the aggregates on solvent quality is investigated. The topology effects are studied by comparing results from linear counterparts of the amphiphiles. It is observed that, in addition to spherical micelles, cylindrical micelles, disklike micelles, vesicles, and large compound micelles, muticompartment vesicles with several fluidic cores can be formed by the cyclic systems. The morphologies are regulated by the interaction parameter εAS between the hydrophobic block and solvents. Furthermore, it is revealed that the differences of characteristics of the self‐assembled aggregates originate from the difference in architectural constraint. The wide region of forming multicompartment vesicles suggests that cyclic amphiphilic macromolecules could be a suitable candidate for applications to deliver multiple functional components by compartmentalizing different components in different confined space of vesicles. 相似文献
77.
We demonstrate high-speed complex conjugate artifact (CCA) resolved imaging of human retina in vivo using spectral domain optical coherence tomography. This technique utilizes sinusoidal reference mirror modulation to implement high-speed integrating buckets acquisition and a quadrature projection reconstruction algorithm in postprocessing. This method is illustrated experimentally using sets of four integrating bucket phase scans, acquired at 52 kHz, for DC suppression of 73 dB and complex conjugate suppression of 35 dB. Densely sampled (3000 A-scans/image, acquired at 4.3 images/s) full-depth in vivo images of optic nerve head show CCA suppression for most image reflections to the noise floor. 相似文献
78.
分等级球状TiO2纳米结构的合成、表征和光催化活性 总被引:3,自引:0,他引:3
以TiCl3作为钛源,添加聚丙烯酰胺(PAM)和尿素,采用水热方法合成了分等级球状TiO2纳米结构。利用场发射扫描电子显微镜(FESEM)、X射线粉末衍射(XRD)、Raman光谱、氮气吸附-脱附分析和紫外-可见漫反射光谱(UV-VisDRS)对产物的形貌、晶相组成、孔结构和紫外-可见光谱性质进行了表征。结果表明,制备的直径为400~600nm的球状TiO2纳米结构由粒径为20~40nm的纳米粒子组装而成。PAM和尿素对分等级球状TiO2纳米结构的形貌和晶相组成有着重要影响。对紫外光照射下分等级球状TiO2纳米结构在甲基橙降解中的光催化活性也进行了研究。 相似文献
79.
Jianglin Zhao Yong Yan Lizhuang Huang Run Yang 《Mathematical Methods in the Applied Sciences》2019,42(11):3831-3847
This paper deals with a diffusive toxin producing phytoplankton‐zooplankton model with maturation delay. By analyzing eigenvalues of the characteristic equation associated with delay parameter, the stability of the positive equilibrium and the existence of Hopf bifurcation are studied. Explicit results are derived for the properties of bifurcating periodic solutions by means of the normal form theory and the center manifold reduction for partial functional differential equations. Numerical simulations not only agree with the theoretical analysis but also exhibit the complex behaviors such as the period‐3, 5, 6, 7, 8, 11, and 12 solutions, cascade of period‐doubling bifurcation in period‐2, 4, quasi‐periodic solutions, and chaos. The key observation is that time delay may control harmful algae blooms (HABs). Moreover, numerical simulations show that the chaotic states induced by the period‐doubling bifurcation are purely temporal, which is stationary in space and oscillatory in time. The investigations may provide some new insights on harmful phytoplankton blooms. 相似文献
80.
Tianliang Hu Run Chen Qiang Wang Chiyang He Shaorong Liu 《Journal of separation science》2021,44(1):274-309
Sample pretreatment is essential for the analysis of complicated real samples due to their complex matrices and low analyte concentrations. Among all sample pretreatment methods, solid‐phase extraction is arguably the most frequently used one. However, the majority of available solid‐phase extraction adsorbents suffer from limited selectivity. Molecularly imprinted polymers are a type of tailor‐made artificial antibodies and receptors with specific recognition sites for target molecules. Using molecularly imprinted polymers instead of conventional adsorbents can greatly improve the selectivity of solid‐phase extraction, and therefore molecularly imprinted polymer‐based solid‐phase extraction has been widely applied to separation, clean up and/or preconcentration of target analytes in various kinds of real samples. In this article, after a brief introduction, the recent developments and applications of molecularly imprinted polymer‐based solid‐phase extraction for determination of different analytes in complicated real samples during the 2015‐2020 are reviewed systematically, including the solid‐phase extraction modes, molecularly imprinted adsorbent types and their preparations, and the practical applications of solid‐phase extraction to various real samples (environmental, food, biological, and pharmaceutical samples). Finally, the challenges and opportunities of using molecularly imprinted polymer‐based solid‐phase extraction for real sample analysis are discussed. 相似文献