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101.
Through the combination of the divergent and convergent approaches, coupled with the utilization of the powerful Sharpless “click‐chemistry” reaction, two series of sulfonyl‐based high‐generation NLO dendrimers were conveniently prepared with high purity and in satisfactory yields. Thanks to the perfect three‐dimensional (3D) spatial isolation from the highly branched structure and the isolation effect of the exterior benzene moieties and the interior triazole rings, these dendrimers exhibited large second harmonic generation coefficient (d33) values up to 181 pm V?1, which, to the best of our knowledge, is the highest value so far for polymers containing sulfonyl‐based chromophore moieties. Meanwhile, compared with the nitro‐chromophore‐based analogues, their optical transparency and NLO stability were improved in a large degree, due to the lower dipole moment (μ) and the special main‐chain structure of sulfonyl‐based chromophore in these dendrimers.  相似文献   
102.
利用Mawhin延拓定理考察了一类分数阶微分方程m点边值共振问题解的存在性.得到了解的存在性的一个充分性条件,并且举出实例用以说明主要结果.  相似文献   
103.
In this article, we use some analytic and geometric characters of the smooth points in a sphere to study the isometric extension problem in the separable or reflexive real Banach spaces. We obtain that under some condition the answer to this problem is affirmative.  相似文献   
104.
It is a well-known fact that characters of a finite group can give important information about the group's structure. Also it was proved by the third author of this article that a finite simple group can be uniquely determined by its character table. Here the authors attempt to investigate how to characterize a finite almost simple group by using less information of its character table, and successfully characterize the almost simple K3-groups by their orders and at most three irreducible character degrees of their character tables.  相似文献   
105.
Transformation of plant-origin 7,14-dihydroxy-ent-kaurenes to ent-abietanes having a cis-fused α-methylene γ-lactones was accomplished efficiently under the Mitsunobu reaction conditions. The yields of the desired products were apparently influenced by the steric hindrance at C-1. The cytotoxic activity on P388 murine leukemia cells of the ent-abietanes having cis-fused α-methylene γ-lactones produced were assayed.  相似文献   
106.
A novel manganese coordination polymer, poly[(μ5‐thiophene‐3,4‐dicarboxylato)manganese(II)], [Mn(C6H2O4S)]n, was synthesized hydrothermally using 3,4‐thiophenedicarboxylate (3,4‐tdc2−) as the organic linker. The asymmetric unit of the complex contains an Mn2+ cation and one half of a deprotonated 3,4‐tdc2− anion, both residing on a twofold axis. Each Mn2+ centre is six‐coordinated by O atoms of bridging/chelating carboxylate groups from five 3,4‐tdc2− anions, forming a slightly distorted octahedron. The Mn2+ centres are bridged by 3,4‐tdc2− anions to give an infinite two‐dimensional layer which incorporates one‐dimensional Mn–O gridlike chains, and in which the 3,4‐tdc2− anion adopts a novel hexadentate chelating and μ5‐bridging coordination mode. The fully deprotonated 3,4‐tdc2− anion exhibits unexpected efficiency as a ligand towards the Mn2+ centres, which it coordinates through all of its carboxylate O atoms to provide the novel coordination mode. The IR spectrum of the complex is also reported.  相似文献   
107.
Six parts of lotus (seeds, leaves, plumule, stamens, receptacles and rhizome nodes) are herbal medicines that are listed in the Chinese Pharmacopoeia. Their indications and functions have been confirmed by a long history of clinical practice. To fully understand the material basis of clinical applications, UPLC-QToF-MS combined with the UNIFI platform and multivariate statistical analysis was used in this study. As a result, a total of 171 compounds were detected and characterized from the six parts, and 23 robust biomarkers were discovered. The method can be used as a standard protocol for the direct identification and prediction of the six parts of lotus. Meanwhile, these discoveries are valuable for improving the quality control method of herbal medicines. Most importantly, this was the first time that alkaloids were detected in the stamen, and terpenoids were detected in the cored seed. The stamen is a noteworthy part because it contains the greatest diversity of flavonoids and terpenoids, but research on the stamen is rather limited.  相似文献   
108.
The liver, kidney and muscle samples from seven cetaceans were digested by microwave digestion, and trace elements amounts of V, Cd, Cu, Zn, As, Cr, Ni, Mn, Se, Hg and Pb were determined by inductively coupled plasma mass spectrometry (ICP-MS), and the health risk assessment for Zn, Cu, Cd, Hg, Se in the liver was conducted. The results of international lobster hepatopancreas standard (TORT-2) showed acceptable agreement with the certified values, and the relative standard deviation (RSD) of eleven kinds of trace elements were less than 3.54%, showing that the method is suitable for the determination of trace elements in cetaceans. The experimental results indicated that different tissues and organs of the dolphins had different trace elements, presenting the tissue specificity. There is a certain inter-species difference among different dolphins about the bioaccumulation ability of the trace elements. The distribution of trace elements in whales presented a certain regularity: the contents of most elements in liver, kidney were much higher than the contents of muscle tissues, Cu, Mn, Hg, Se, and Zn exhibit the higher concentrations in liver, while Cd was mainly accumulated in kidney. And according to the health risk assessment in liver, the exceeding standardrate of selenium and copper in seven kinds of whales was 100%, suggesting that these whales were suffering the contamination of trace elements. The experimental results is instructive to the study of trace elements in cetaceans, while this is the first report for the concentrations in organs of Striped dolphin, Bottlenose dolphin, Fraser's Dolphin and Risso's dolphin in China, it may provide us valuable data for the conservation of cetaceans.  相似文献   
109.
以光纤Bragg光栅位移传感器对淮北朱仙庄煤矿顶板离层监测为实际数据依据,选择最佳的典型函数模型对顶板离层进行非线性回归分析,得出能够反映位移发展趋势的回归曲线。监测结果与回归拟合数据表明:非线性回归分析预测方法不仅可以反映煤矿顶板离层实时变化过程,还能根据其变化趋势进行巷道稳定性判断。  相似文献   
110.
利用第一性原理,设计并研究了一类基于单臂碳纳米管的分子封装的分子体系.计算表明,半环葫芦脲类化合物可有效封装碳纳米管,引入微弱的分子间相互作用,对碳纳米管的电子态能级结构分布 仅带来微弱影响.半环葫芦脲分子与碳纳米管在管径方向的一维电子态波函数充分耦合,进而有效改变了一些前沿分子轨道的波函数在管径两头的分布以及相应的电子布居浓度.基于电子输运的模拟,发现半环葫芦脲分子在碳纳米管一维方向滑动时的某个电压下的电导变化可准确反映电子态波函数在相应分子导电通道上的一维分布信息.  相似文献   
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