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61.
The synthesis and structure of a giant 102-silver-atom nanocluster (NC) 1 is presented. X-ray structural analysis reveals that 1 features a multi-shelled metallic core of Ag6@Ag24@Ag60@Ag12. An octahedral Ag6 core is encaged by a truncated octahedral Ag24 shell. The Ag24 shell is composed of a hitherto unknown sodalite-type silver orthophosphate cluster (SOC) {(Ag3PO4)8}, reminiscent of the Ag3PO4 photocatalyst. The SOC is capped by six interstitial sulfur atoms, giving a unique anionic cluster [Ag6@{(Ag3PO4)8}S6]6−, which functions as an intricate polyhedral template with abundant surface O and S atoms guiding the formation of a rare rhombicosidodecahedral Ag60 shell. An array of 6 linear Ag2 staples further surround this Ag60 shell. [Ag6@{(Ag3PO4)8}S6]6− is an unusual Ag-based templating anion to induce the assembly of a SOC within silver NC. This finding provides molecular models for bulk Ag3PO4, and offers a fresh template strategy for the synthesis of silver NCs with high symmetry.  相似文献   
62.
Sol–gel dip-coating technique can be used to fabricate SiO2–TiO2 composite film with self-cleaning and anti-reflectance properties from low-cost SiO2 colloid solution and Ti(OC4H9)4. The physical and structural properties have been investigated by UV–visible spectrophotometer, contact angle meter, XRD, FT-IR, FESEM. UV–vis spectra and methyl orange photodegradation experiments showed that the SiO2–TiO2 composite film had high light transmittance and photocatalytic activity.  相似文献   
63.
光束质量测量的最小束斑法   总被引:1,自引:0,他引:1  
基于最小束斑条件,提出一种光束质量的测试方法。用这种测试方法,在沿光轴的二个位置进行束宽测量,就可较正确给出束腰位置、束腰宽度、远场发散角和M~2因子。  相似文献   
64.
本实验建立了钯-硝酸镁基体改进剂石墨炉原子吸收光谱法测定六味地黄丸中锡的方法。研究了基体改进剂的加入方式对测定的影响。方法的相对标准偏差为2.5%,回收率在90%~110%之间,检出限为0.3ng/mL。本方法可用于中成药中锡的测定。  相似文献   
65.
In this paper, 2-microlocal Herz type Besov and Triebel-Lizorkin spaces with variable exponents are introduced for the first time. Then, we give characterizations of these spaces by so-called Peetre's maximal functions. Further, the atomic and molecular decompositions of these spaces are obtained. Finally, using the characterizations of the spaces by local means and molecular decomposition we obtain the wavelet characterizations.  相似文献   
66.
Plant diseases reduce crop yield and quality, hampering the development of agriculture. Fungicides, which restrict chemical synthesis in fungi, are the strongest controls for plant diseases. However, the harmful effects on the environment due to continued and uncontrolled utilization of fungicides have become a major challenge in recent years. Plant-sourced fungicides are a class of plant antibacterial substances or compounds that induce plant defenses. They can kill or inhibit the growth of target pathogens efficiently with no or low toxicity, they degrade readily, and do not prompt development of resistance, which has led to their widespread use. In this study, the growth inhibition effect of 24 plant-sourced ethanol extracts on rice sprigs was studied. Ethanol extract of gallnuts and cloves inhibited the growth of bacteria by up to 100%. Indoor toxicity measurement results showed that the gallnut and glove constituents inhibition reached 39.23 μg/mL and 18.82 μg/mL, respectively. Extract treated rice sprigs were dry and wrinkled. Gallnut caused intracellular swelling and breakage of mitochondria, disintegration of nuclei, aggregation of protoplasts, and complete degradation of organelles in hyphae and aggregation of cellular contents. Protection of Rhizoctonia solani viability reached 46.8% for gallnut and 37.88% for clove in water emulsions of 1000 μg/mL gallnut and clove in the presence of 0.1% Tween 80. The protection by gallnut was significantly stronger than that of clove. The data could inform the choice of plant-sourced fungicides for the comprehensive treatment of rice sprig disease. The studied extract effectively protected rice sprigs and could be a suitable alternative to commercially available chemical fungicides. Further optimized field trials are needed to effectively sterilize rice paddies.  相似文献   
67.
Detecting point targets in infrared images is a difficult task. Template matching is simple and easy to implement for completing this task. However, it has some shortcomings. We propose an improved template matching method for detecting targets. Different from the classic template matching, the projection coefficients obtained from principal component analysis are used as templates and the nonlinear correlation is proposed to measure the similarity, the matching degree. The correlation in original space can not capture the higher-order statistical property of images. So its detection performance is not satisfying. We introduce the nonlinear correlation, which computes the correlation coefficients in a higher-dimensional feature space or even in an infinite-dimensional feature space, to capture the higher-order statistics. The detection performance is improved greatly. Results of experiments show that the improved method is competent to detect infrared point targets.  相似文献   
68.
合成了具有规整六方棱柱形貌的大孔笼型介孔硅, 通过液相自组装的方法将共轭聚合物链填入孔中, 制备了无机介孔硅-共轭聚合物的纳米复合物. 并利用SEM, TEM, XRD以及N2吸附等测试表征了介孔硅和复合物. 通过研究这种介孔硅负载长链共轭聚合物的UV-vis光谱、PL光谱以及发光动力学, 证明了聚合物链的聚集作用受到强烈的抑制而链活动能力减弱, 链间激子的能量分布变窄; 链间激子在介孔受限环境中寿命延长. 激光扫描共聚焦显微镜研究发现复合物硅微粒的发光强度比聚合物聚集体的发光强度高20倍以上. 纳米复合物在高温下仍然保持较高的发光强度, 有效的减少了酮缺陷的产生. 光稳定性测试表明该纳米复合物还具有较高的抗光氧化能力.  相似文献   
69.
叶绿体不同浓度下光诱导延迟荧光光谱研究   总被引:8,自引:6,他引:2  
王成龙  钱隆  范多旺  王锦辉 《光子学报》2005,34(7):1028-1031
针对《光子学报》文献[1]中实验结果与已有报道相关光谱特征的显著差异,利用多种光谱学手段对不同浓度下叶绿体延迟荧光行进了研究.实验结果表明:PSⅠ反应中心叶绿素P700对PSⅡ所发685 nm成份的吸收随叶绿体浓度的增加而增强,从而导致PSⅠ发出的730 nm成份增强,而使得延迟荧光光谱中730 nm成为主峰,甚至685 nm成份的消失.该研究结果表明:叶绿体延迟荧光光谱中730 nm成份,是由PSⅠ作用中心叶绿素P700对PSⅡ中所发685 nm成份延迟荧光的重吸收,产生激发态所发出的荧光.该结论有助于延迟荧光光谱中各成份产生机理的进一步研究.  相似文献   
70.
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