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11.
Three new flavonol 3-O-glycosides, rhamnetin 3-O-[(S)-3-hydroxy-3-methyl-glutaroyl(1→6)]-β-D-glucopyranoside (1), rhamnocitrin 3-O-[(S)-3-hydroxy-3-methylglutaroyl(1→6)]-β-D-glucopyranoside (2), and isorhamnetin 3-O-[(S)-3-hydroxy-3-methylglutaroyl(1→6)]-α-L-rhamnopyranosyl(1→2)-β-D-glucopyranoside (3), along with 13 known compounds, were isolated from Oxytropis racemosa TURCZ. Their structures were deduced by means of spectroscopic methods and chemical evidence. 2 and 6 showed cytotoxic activities against HCT-8 (IC?? 6.38 μM) and A549 (IC?? 5.20 μM), respectively. 相似文献
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13.
从一般力学的二类变量的广义变分原理的角度,说明了一类变量的Hamilton原理的约束方程中的qε+β具有双重含义:第一种含义是不能仅仅通过积分约束方程求得它的解,即约束是非完整的;第二种含义是qε+β的导数必为ε+β,即满足关系式ε+β=(d)/(dt)qε+β.虽然上述双重含义是并存在的,但是,在某种情况下第一种含义表现得比较明显,在另一种情况下第二种含义表现得比较明显.在此基础上,推导出Четаев条件的几种等价的表达形式;说明了qε+β的双重含义在全部代入法和Lagrange乘子法中的体现. 相似文献
14.
将有关文献给出的一般加载规律一维全量理论的简单模型推广到一般加载规律的一维增量理论,进而推广到一般加载规律的多维增量理论.在此基础上,建立了推导一般加载规律的多维增量理论的本构关系的一种途径.应用这种途径,从应力空间的加载函数和应变空间的加载函数出发,推导了等向强化材料和被加热的等向强化材料的一般加载规律的弹塑性本构关系的两种表示形式.理论和实例均表明,这种途径对等向强化材料、随动强化材料和理想弹塑性材料均适用. 相似文献
15.
A highly sensitive and selective electrochemiluminescent (ECL) biosensor for the determination of adenosine was developed. Single DNA (capture DNA) was immobilized on the gold electrode through Au-thiol interaction at first. Another DNA modified with tris(2,2'-bipyridyl) ruthenium(II)-doped silica nanoparticles (Ru-SNPs) that contained adenosine aptamer was then modified on the electrode surface through hybridizing with the capture DNA. In the presence of adenosine, adenosine-aptamer complex is produced rather than aptamer-DNA duplex, resulting with the dissociation of Ru-SNPs-labeled aptamer from the electrode surface and the decrease in the ECL intensity. The decrease of ECL intensity has a direct relationship with the logarithm of adenosine concentration in the range of 1.0×10(-10) to 5.0×10(-6)molL(-1). The detection limit of the proposed method is 3.0×10(-11)molL(-1). The existence of guanosine, cytidine and uridine has little interference with adenosine detection, demonstrating that the developed biosensor owns a high selectivity to adenosine. In addition, the developed biosensor also demonstrates very good reusability, as after being reused for 30 times, its ECL signal still keeps 91% of its original state. 相似文献
16.
Zhi Kong Lifu WangZhaoxia Wu 《Journal of Computational and Applied Mathematics》2011,236(6):1521-1530
There are many uncertain problems in practical production and life which need decisions made with soft sets and fuzzy soft sets. However, the basis of evaluation of the decision method is single and simple, the same decision problem can obtain different results from using a different evaluation basis. In this paper, in order to obtain the right result, we discuss fuzzy soft set decision problems. A new algorithm based on grey relational analysis is presented. The evaluation bases of the new algorithm are multiple. There is more information in a decision result based on multiple evaluation bases, which is more easily accepted and logical to one’s thinking. For the two cases examined, the results show that the new algorithm is efficient for solving decision problems. 相似文献
17.
In our previous research (Liu et al., J Anal Appl Pyrol 63:303–325, 2002), the pseudo bi-component separated-stage model (PBSM)
was suggested for the kinetic analysis on the decomposition of lignocellulosic materials in air at relatively lower heating
rates. As a continuing work, this paper is intended to investigate the applicability of PBSM at different heating rates by
experimental analyses. Decomposition of oil tea wood has been studied by means of non-isothermal thermogravimetric analysis
in air atmosphere at 10–25 K min−1 heating rates. A two-step parallel reaction kinetic model is used to optimize the kinetic parameters of these materials in
air. Meanwhile, an improved PBSM is developed to describe the thermal degradation process of oil tea wood. Furthermore, a
comparison between the kinetic results of parallel model and PBSM reveals realistic applicability of PBSM. It is concluded
that the PBSM has relatively high accuracy for the first decomposition step in the lower temperature range, while fails to
predict the thermal decomposition behavior in the char oxidative process which occurs in the higher temperature range. 相似文献
18.
SAF双波长光度法测定痕量锗 总被引:2,自引:0,他引:2
在0.6-3.5mol.L^-1盐酸介质中,在阳离子表面活性剂溴化十六烷基三甲基胺和过量的水杨基荧光酮存在下,Ge(Ⅳ)与SAF形成1:4的配合物。配合笺可稳定15h,将所拟方法用于烟道灰中痕量锗的测定,结果令人满意。 相似文献
19.
葡萄糖在KRPB生理缓冲溶液中电还原反应的研究 总被引:1,自引:0,他引:1
葡萄糖在KRPB生理缓冲溶液中电还原反应的研究朱庆存,姜力夫,郁章玉,陈常峰,周正宇(曲阜师范大学,电化学研究所,曲阜273165)关键词:葡萄糖,扩散系数,磷酸盐生理溶液。本文从葡萄糖在铂电极上的电氧化还原峰电流与pH值的线性关系,扩散系数与葡萄糖... 相似文献
20.
Photon affinity can serve as a probe for predicting the structures of protonated homodimers of amino acids. 相似文献