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61.
[目的]为了明确从吉林省长白山保护区池西保护站马鞍山云杉人工林林下土壤分离,所获得1株拮抗菌株(编号记为CX3)的生防效果及分类地位。[方法]分别采用平板对峙法和杯碟法测定该菌株活菌及其发酵液的抑菌活性和抑菌谱;并通过形态学、生理生化特征、16S rRNA序列分析等方法研究了其分类地位。[结果]该菌株对13种供试植物病原菌均有抑制作用,抑菌谱广,其中对蓝莓溃疡病菌有极强的抑制作用,抑菌带达25.91 mm,发酵液的抑菌圈直径达31.73 mm;根据其菌株形态、生理生化特性、16S rRNA序列比对,最终鉴定菌株为链霉菌属Streptomyces sp.。[结论]该菌株对蓝莓溃疡病菌有显著的抑制效果,应用开发前景良好,此次是国内首次报道该菌株杀真菌活性。 相似文献
62.
63.
Junfeng Xiang Lijing Xie Feinong Gao Jie Yi Siqin Pang Xibin Wang 《Ceramics International》2018,44(10):11765-11777
In industrial forming and machining process, the large plastic deformation of material takes place in wide loading ranges of strain-rate and forming temperature. A satisfactory modelling of quasi-static and dynamic material behaviors is of great importance for understanding physical process and processes optimization. A dependence-based integrated methodology, together with an improved weighted multi-objective parameter identification strategy is presented for the development of phenomenological constitutive model and the parameter identification using experimental data from quasi-static and dynamic tests with instantaneous strain rate variations and plastic strain-related temperature changes. The improved multi-objective parameter identification model is reformulated by introducing three weighting factors for valuing different measure errors and fit standard errors in individual objective function corresponding to each test, considering the sampling point number and active material parameter number under different loading conditions, and balancing optimization opportunity of quasi-static and dynamic sub-objective functions. The methodology is verified for feasibility through illustrative constitutive identification for SiCp/Al composites. This may provide a methodology of constitutive modelling for predicting material behaviors in quasi-static and dynamic modes equally well. 相似文献
64.
The identification rate of UHF RFID system was restricted by multipath propagation effects.The system identification performance was studied considering the correlation coefficient between forward and reverse channels.Based on the generalized Rician fading channel model,the analytical expression of identification rate was derived under independent,full correlation and correlation cases.Compared with the existing analysis,the proposed uniform calculation formula of identification rate was for any correlation coefficient and kinds of channel conditions.The numerical computation and Monte-carlo simulations show that the influences of different correlation coefficients,channel conditions,sensitivity and distance on the identification rate. 相似文献
65.
Minimization of the Theoretical Error of Input Parameters for a Vapor Permeation Apparatus 下载免费PDF全文
Pavel Dytrych Zuzana Vajglová Lenka Morávková Věra Jandová Pavel Izák Zuzana Petrusová 《化学工程与技术》2018,41(9):1727-1736
All input experimental errors for membrane flux determination were analyzed. The overall error in pressure did not largely influence the determination of membrane flux. The main contribution to errors was ascribed to flow meters and membrane thickness. The choice of an optimal operational range for input parameters led to elimination of at least 2/3 of the theoretical relative error for subsequent evaluation of the permeability of individual species. This is especially valuable for low‐permeable membranes, whereas a very low relative theoretical error can be obtained in the case of highly permeable materials. 相似文献
66.
Yiguang Jiang Benxue Jiang Qihua Zhu Nan Jiang Pande Zhang Shuilin Chen Xu Hu Ge Zhang Jintai Fan Liangbi Su Jiang Li Long Zhang 《Journal of the European Ceramic Society》2018,38(5):2404-2409
Different deformation rates of Nd,Y-codoped CaF2 transparent ceramics were prepared by ceramization of single crystals. The deformation rate effects on the crystallization behaviors, microstructures, mechanical properties, and optical performances were investigated for the first time. The results indicate that the comprehensive performances of Nd,Y-codoped CaF2 ceramic (△a?=?62%) are the most optimal compared with other ceramics having different deformation rates (△a?=?34%, 40%, 50%, and 75%). In further investigations of the optical properties, the Nd,Y-codoped CaF2 ceramic (△a?=?62%) sample exhibited a high transparency (Ta?>?91%, 3-mm thick,250?~?1200?nm), low light scattering, superior fracture toughness (K1c?~?0.71?MPa·m1/2), strong fluorescence emission, long lifetime (τ?=?348.72?μs), and broad FWHM (29.2?nm), promising a good candidate for high-power laser material. 相似文献
67.
细菌纤维素(BC)因其独特性能被广泛应用于医药、食品等领域,目前其高产量菌株筛选、合成成本降低及合成途径改良等成为研究热点。本文依据国内外文献并结合团队研究成果对BC合成与鉴定的相关研究进行综述。首先对BC合成菌筛选及碳源利用的研究进行了分析,总结了降低BC合成成本的研究思路。其次对鉴定菌株合成产物的方法进行了归纳,总结了不同方法的特点。然后结合本团队筛选出的BC生产菌XJL-06-4 BC合成酶基因分析结果,综述了BC合成途径、合成酶存在形式以及基因水平调控作用,为BC在分子水平上通过改变合成途径提高产量提供新思路。最后,总结BC微生物发酵生产存在的问题,多角度提出解决方案。 相似文献
68.
Krishnan Balasubramanian 《Fullerenes, Nanotubes and Carbon Nanostructures》2020,28(9):687-696
AbstractWe have developed combinatorial generation function methods that combine M?bius inversion and character cycle indices for the enumeration of stereo, position and chiral isomers of icosahedral giant fullerenes C180 and C240. Techniques are also developed for the machine perception of symmetries of especially giant fullerenes. The techniques yield, symmetries, position, stereo and chiral isomers of giant fullerenes which we illustrate with applications to icosahedral C180(Ih), and C240(Ih). We have obtained combinatorial tables for the isomers of C180Xk and C240Xk. Our results point to errors in previous computations on C240 permutations. We have also outlined applications to NMR and ESR spectroscopy. 相似文献
69.
Zhen Luo Zhuoqing Li Zhe Xie Inna M. Sokolova Lan Song Willie J. G. M. Peijnenburg Menghong Hu Youji Wang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(36)
Titanium dioxide nanoparticles (nano‐TiO2) are widely used in consumer products, raising environmental and health concerns. An overview of the toxic effects of nano‐TiO2 on human and environmental health is provided. A meta‐analysis is conducted to analyze the toxicity of nano‐TiO2 to the liver, circulatory system, and DNA in humans. To assess the environmental impacts of nano‐TiO2, aquatic environments that receive high nano‐TiO2 inputs are focused on, and the toxicity of nano‐TiO2 to aquatic organisms is discussed with regard to the present and predicted environmental concentrations. Genotoxicity, damage to membranes, inflammation and oxidative stress emerge as the main mechanisms of nano‐TiO2 toxicity. Furthermore, nano‐TiO2 can bind with free radicals and signal molecules, and interfere with the biochemical reactions on plasmalemma. At the higher organizational level, nano‐TiO2 toxicity is manifested as the negative effects on fitness‐related organismal traits including feeding, reproduction and immunity in aquatic organisms. Bibliometric analysis reveals two major research hot spots including the molecular mechanisms of toxicity of nano‐TiO2 and the combined effects of nano‐TiO2 and other environmental factors such as light and pH. The possible measures to reduce the harmful effects of nano‐TiO2 on humans and non‐target organisms has emerged as an underexplored topic requiring further investigation. 相似文献
70.
Al Mamun 《Polymer Engineering and Science》2020,60(11):2702-2709
A quantitative analysis method for the distribution of noncrystalline poly(butadiene) component in poly(ε-caprolactone)/poly(butadiene) (PCL/PB) binary blends have been analyzed by advance application of Raman spectroscopy, optical microscopy, and differential scanning calorimetry (DSC) techniques. Thin films of different compositions of PCL/PB binary blends were prepared from solution and isothermally crystallized at a certain temperature. After calibration with real data, quantitative analyses by Raman spectroscopy revealed the amorphous PB are trapped inside the PCL crystals. Polarized optical microscopy and real time atomic force microscopy were used to collect data for the crystal morphology and crystal growth rate. For pure PCL crystals, a morphology of truncated lozenge shape was observed, independent of crystallization temperature and regardless of the blends compositions. For the pure PCL and their blends, almost unique crystal growth rate was found. The miscibility behaviors using DSC were drawn through melting point depression method. The Hoffman-Weeks extrapolations of the blends were found to be linear and identical with those of the neat PCL. The interaction parameter for the blends indicating that the PCL and PB blends have no intermolecular interaction, confirming the blends are immiscible. Despite the immiscibility of the blend, the PCL crystals do not bend during the growth process and do not reduce the growth rate as they do for miscible blend systems. 相似文献