从苦荞麦中提取芦丁的研究

本文采用碱提取酸沉淀加醇类的方法，从苦荞麦中提取芦丁，较好地解决了过滤和干燥难的问题，既提高了收率，又降低了成本。     

强流脉冲离子束辐照钨靶温度场演化数值研究

强流脉冲离子束(HIPIB)使材料表面气化产生喷发等离子体从而进行薄膜生长、纳米粉的制备等工作。金属钨的熔点高,热导性好,是耐高热流密度防护层最可能的材料。为了研究金属钨在高热负荷下的响应,建立了HIPIB辐照钨靶的考虑相变的非线性热力学方程,并采用有限元方法数值求解了靶材辐照后的二维温度场演化问题,得到了钨靶温度场的时空演化规律。当离子束流密度为100 A/cm2时,脉冲结束后束流入射中心表层约0.3μm厚的材料熔化,且熔化是从表面开始的,而后因热传导固化;脉冲结束后开始时靶材表面温度急剧下降,而后变得缓慢,温降的梯度在不同时刻均存在峰值,且随时间增加峰值向纵向深度处移动。     

沈阳市居住区绿地植物造景现状与发展趋势

通过对沈阳市居住区绿地进行抽样调查,对沈阳市居住区绿地植物造景现状及存在的问题进行了综合分析,结合沈阳实际情况,展望了其发展趋势。     

基于图切割的快速运动分割方法

基于图切割的图像分割是近几年发展的一项新技术,但随着图像大小及空间维数的增加,图切割的运算量成为负担。针对运动分割提出了一种快速图切割方法,利用运动分割的特点将差分图像中不变的背景映射为一点或几点,然后参与网络图的构造和图切割的求解,以减少图切割运算量。通过实验将这种快速方法应用于2D图切割和3D图切割,对图像序列的运动目标分别进行了自动分割。实验结果表明,这种快速图切割方法不仅大大地降低了存储消耗,提高了运算速度,而且也获得了良好的分割结果。结果证明这种方法在运动目标的分割中是行之有效的。     

用EGSnrc程序包对单能电子实验过程影响因素的研究

本文运用蒙特卡罗程序EGSinpRZ和EGSnrcMP模拟了不同能量的单能电子入射过程中与AL吸收物质的作用,得到了该过程产生并且进入了灵敏区的轫致辐射光子和散射电子平均能量以及他们在相应情况下的百分比,结合两种测量方法(全峰面积法TPA和半峰面积法SPA)讨论了轫致辐射和散射对测量结果的影响;研究了实验所用放射源与其包装材料产生的轫致辐射光子对测量的影响;同时用EGSnrcMP程序模拟了吸收过程,画出了吸收曲线,并与实验吸收曲线相比较,讨论了环境本底对计数的影响.     

Valence electron structure analysis of refining mechanism of Sc and Ti additions on aluminum

The mechanism of the difference of refining effect between Sc and Ti adding to aluminum can not be explained substantially with traditional theory. Valence electron structures of Al-Ti and Al-Sc alloys have been studied by using the empirical electron theory of solids and molecules (EET). The covalent bond electron numbers and interfacial electron density differences are calculated. The conclusion is that, in the two alloys, different covalent bond electron numbers of nucleation particles, and different electron densities on the interface between the second phase particles and the matrix, fundamentally lead to the difference of refining effect between Sc and Ti adding to aluminum. Supported by the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20050003042)     

Experimental investigation on the flow structure over a simplified Papilio Ulysses model

The aerodynamic characteristics of butterflies, especially those which can migrate overseas, have received a great deal of attention because they have larger-scale wingspans and lower flapping frequencies than other insects such as drosophilae and bees. The objective of this work is to investi-gate the flow structures over a simplified model of Papilio Ulysses, one kind of migratory butterflies, through hydrogen bubble visualizations, and leading-edge vortices, wing-tip vortices, separation bub-bles and horseshoe vortex wake are observed. Moreover, the variations of these structures with the angle of attack are discussed in detail. A new type of leading-edge vortices which resembles the in- versed Chinese character “八” is observed in the experiment.     

Genome-wide distribution of histone H3 acetylation in all- trans retinoic acid induced neuronal differentiation of SH-SY5Y cells

With chromatin immunoprecipitation (ChIP) and promoter DNA microarray analyses (ChIP-on-chip), we analyzed the variations of acetylation on histone H3 in all-trans retinoic acid (RA) induced neuronal cell differentiation. Neuroblastoma SH-SY5Y cells were treated with RA for 24 h and the acetylation on histone H3 in the promoter region of the genes was detected. Results showed that, after treatment, the level of acetylation on histone H3 elevated in 597 genes in the genome, and reduced in the other 647 genes compared with those of the control. In summary, we have successfully adopted a high throughput technique to detect and analyze variations of acetylation of histone H3 in human genome at the early phage of RA induced neuronal differentiation of the SH-SY5Y cells. Supported by National Natural Science Foundation of China (Grant Nos. 90408007 and 30721063) and National Key Basic Research and Development Program of China (Grant No. 2004CB518605)     

On the measurement of slip length for liquid flow over super-hydrophobic surface

To design a surface with large slip or larger drag reduction is a pop issue in the fields of liquid transporting and body swimming. In this context, it is a crucial problem to measure the slip length for these surfaces. Here we propose a novel method by using rheometer for this objective. This method is implemented by designing the distribution of the super-hydrophobic area on the sample. Using this method, a slip length of 40 μm for 70 wt% glycerin flow over a super-hydrophobic surface with stripe structure （the period, width and height of ridges are 150 μm, 40 μm and 65 μm, respectively） is measured. The result shows that the slip length measured using this method is in good agreement with former results measured by other methods. This method is fit for measuring the slip length of super-hydrophobic surface whose structure ranges from microto nano-scale.     

Record of environmental change by α-cellulose δ13C of sphagnum peat at Shennongjia, 4000―1000 aBP

The Dajiuhu Basin at Shennongjia, located within typical East Asian Monsoon region, preserves a sub-alpine sphagnum peat deposition in its central area. The topmost 120 cm of the peat covers the last 4000 years according to AMS ^14C dating of pollen concentration. Carbon isotope of a-cellulose, extracted from sphagnum peat, provides a quantitative reconstruction of atmospheric relative humidity, based on transfer functions of C3 plants carbon isotopic fractionation equation and the bryophyte photosynthesis CO2 absorption rate equation. δ^13C, TOC and C/N variations reveal that the Dajiuhu area has experienced a long-term tendency to dry during 4000-1000 aBP, with a major transition happening around 3000 aBP. Four relative dry events are identified at 3400-3200, 3000-2600, 2200-2000 and 1600-1400 aBP, respectively, corresponding to those climate events documented in many global records. Three periodicities, 664 a, 302 a and 277 a enclosed in the atmospheric humidity of Dajiuhu are correlated to the cycles of solar activities. The weakening of East Asia summer monsoon during this period registered in the Dajiuhu peat is consistent with the synchronous weakening of Indian Monsoon. This trend may be attributed to gradual decrease of Northern Hemispheric summer solar insolation and the consequently southward migration of Intertropical Convergent Zone （ITCZ）.