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161.
在水力-力学本构模型基础上,采用化学软化公式引入孔隙水中含盐、碱类等离子类溶质对土体前期固结压力的影响,得到土体的化学-水力-力学耦合本构模型(C-H-M 模型). 根据试验结果对化学软化公式的参数进行数值拟合,通过算例验证了C-H-M 本构模型的有效性  相似文献   
162.
We demonstrate the reduction of oxidized to reduced glutathione in the presence of glutathione reductase enzyme based on the modulation in photoluminescent quenching efficiency between the perylene bisimide chromophore TPPCA and gold nanoparticles (AuNPs). The TPPCA-AuNPs assembly shows a turn-on fluorescent signal in the presence of reduced glutathione, which provides a new concept to measure the balance of glutathione in a creature.  相似文献   
163.
There is a well-recognized need to develop Bayesian computational methodologies that scale well to large data sets. Recent attempts to develop such methodology have often focused on two approaches—variational approximation and advanced importance sampling methods. This note shows how importance sampling can be viewed as a variational approximation, achieving a pleasing conceptual unification of the two points of view. We consider a particle representation of a distribution as defining a certain parametric model and show how the optimal approximation (in the sense of minimization of a Kullback-Leibler divergence) leads to importance sampling type rules. This new way of looking at importance sampling has the potential to generate new algorithms by the consideration of deterministic choices of particles in particle representations of distributions.  相似文献   
164.
In this article, we propose a novel finger multimodal biometric authentication that combines finger vein, fingerprint, finger shape and finger knuckle print features of a single human finger. The proposed multimodal biometrics provides score-level fusion approach based on triangular norm with four finger biometric traits, instead of two or three ones combined in the previous approaches. The experimental evaluations and analysis are conducted on a merged multimodal biometrics database. The results show that the proposed score-level fusion approach using triangular norm obtains a larger distance between genuine and imposter score distribution as well as achieves lower error rates. Moreover, the comparison results suggest that the proposed score level fusion of finger biometrics using triangular norm outperforms the state-of-the-art approaches.  相似文献   
165.
Li J  Todaro LJ  Mootoo DR 《Organic letters》2008,10(7):1337-1340
The synthesis of the tricyclic enone 2, corresponding to the AB subunit of the novel tyrosine kinase inhibitor angelmicin B, is described. The strategy centers on an intramolecular Diels-Alder (IMDA) reaction on triene 4 to provide the complex decalin 3, which is elaborated to 2. Other key steps are the formation of the THF ring in 2 through a tandem alkoxy radical fragmentation-etherification on the lactol derived from 3, and the synthesis of 4 via a ring-closing ene-yne metathesis (RCEYM).  相似文献   
166.
Visible near-infrared chemosensor for mercury ion   总被引:2,自引:0,他引:2  
Zhu M  Yuan M  Liu X  Xu J  Lv J  Huang C  Liu H  Li Y  Wang S  Zhu D 《Organic letters》2008,10(7):1481-1484
A visible near-infrared chemosensor (MCy-1) for mercury ions was successfully devised and characterized. A large red-shift (122 nm) of the absorption maximum of MCy-1 was observed. An important feature for the new chemosensor is its high selectivity towards mercury ions over the other competitive species, making the "naked-eye" detection of mercury ions possible.  相似文献   
167.
Liu T  You D  Valenzano C  Sun Y  Li J  Yu Q  Zhou X  Cane DE  Deng Z 《Chemistry & biology》2006,13(9):945-955
The polyketide synthase (PKS) for the biosynthesis of the polyether nanchangmycin lacks an apparent thioesterase comparable to the type I thioesterase domains of the modular PKSs responsible for macrolide biosynthesis. Three candidate polyether chain-releasing factors were examined. Both the putative CR domain and the NanE protein appeared to be genetically relevant. Among the three heterologously expressed soluble proteins (recombinant CR domain, the ACP-CR didomain, and NanE) tested, only NanE hydrolyzed the polyether-SNAC. By contrast, recombinant DEBS TE from the erythromycin pathway, and the recombinant MonAX, a type II TE associated with the polyether monensin biosynthesis for which a homolog has not been detected in the nanchangmycin cluster, hydrolyzed a diketide-SNAC but not the polyether-SNAC. We could thus conclude that NanE is a dedicated thioesterase mediating the specific release of the polyether chain during nanchangmycin biosynthesis.  相似文献   
168.
Niobium doping increases the visible light adsorption of titanate nanoflakes, which greatly enhances the photocatalytic activity for ibuprofen elimination.  相似文献   
169.
A new kind of one-dimension attapulgite (APG) @ titanium oxide nanoparticles was prepared via kinetics-controlled coating method. By simply altering the ammonia content and reaction time to control the kinetics of hydrolysis and condensation of tetra-n-butyl titanate (TBOT) in ethanol/ammonia mixtures, amorphous titanium oxide nanoparticles can adhere to the APG rods firmly, and the thickness of uniform amorphous titanium oxide shells can be adjusted from 0 to 40 nm. The obtained APG@ titanium oxide nanorods were applied as a new electrorheological (ER) fluid, which showed a promising ER activity. The yield stresses of the APG@ titanium oxide nanorod (40-nm shell thickness) ER fluid under electric field was 2.1 times of the granular titanium oxide ER fluid and 4.1 times of the APG ER fluid. And, the APG@ titanium oxide nanorod ER fluid also exhibited distinctly improved suspended stability.  相似文献   
170.
以氧化镁/三聚氰胺/聚乙二醇混合物为初始原料,通过模板辅助的方法成功地制备了高储锂性能的氮掺杂多孔炭片(NPCSs).采用红外光谱(FTIR)、X射线粉末衍射(XRD)、X射线光电子能谱(XPS)、扫描电镜(SEM)、透射电镜(TEM)、循环伏安(CV)、恒流充放电(GCD)和交流阻抗(EIS)对样品进行了详细地表征和分析.结果显示:NPCSs为交错连接的多孔炭片网络,并显示出较高的比表面积(370.8 m2·g-1)、多级的孔道和高的氮含量(8.5 at%).这种连续多孔的结构,有利于电子在三维方向的传输,缩短了锂离子扩散的距离,扩大了锂离子与电极的接触面积,也为锂离子的储存提供了有利场所.此外,高的氮掺杂水平为锂离子的嵌入和脱出提供了大量的活性位点,增强了材料的导电性.基于此独特的结构,NPCSs电极显示了高的首次可逆比容量(电流密度为100 mA·g-1时,扣除乙炔黑贡献后的比容量为914 mAh·g-1)和较好的循环稳定性(电流密度为1000 mA·g-1,循环至300圈,仍保留523 mAh·g-1的比容量).而且,该材料显示出较高的倍率性能,在电流密度为3000 mA·g-1时的可逆比容量达到355 mAh·g-1.因此,所获得的NPCSs有望成为锂离子电池负极材料.  相似文献   
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