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1.
广义不确定系统鲁棒稳定性及鲁棒镇定的矩阵不等式方法 总被引:6,自引:1,他引:5
考虑广义不确定系统的鲁棒稳定性及鲁棒镇定问题.提出了广义不确定系统'广义二
次稳定'及'广义二次可镇定'的概念,利用矩阵不等式,分别得到了所考虑广义不确定系统广义
二次稳定及广义二次可镇定的充要条件,而且,使广义不确定系统鲁棒镇定的状态反馈控制律
的设计可通过求解一给定的矩阵不等式而得到. 相似文献
2.
随着计算流体力学(CFD)的迅速发展,对作为CFD关键技术之一的网络生成技术提出了更高的要求,传统的网络生成方法一般耗费机时较多且复杂难用,或者生成的网格正交性较差。笔者在传统方法的基础上,提出了一种结合分块网格技术的多方向混合插值网格生成方法,其中插值系数对各块子区域网格的正交性具有可调节作用,能够处理各种复杂边界,生成的网格正交性好,适用范围较广,耗费机时也相对较少,大量的计算实例证明了新方法在网格正交性、适用性等方面都具有优势。 相似文献
3.
为有效防控储藏稻谷霉变,确保稻谷在储藏期的品质与安全,本研究先后对同一粮库点新入库、储藏1年、储藏2年及储藏3年稻谷样品进行了采集,并对其真菌群落多样性进行了探究。通过Illumina MiSeq序列分析法,探究了不同储藏年限稻谷的真菌群落多样性,优势菌属以及真菌群落随储藏年限增加的演变规律。结果发现新入库储藏稻谷的真菌群落多样性远大于储藏期稻谷。此外,储藏稻谷的优势菌属包括假丝酵母菌属(Gibberella),曲霉属(Aspergillus),帚枝霉属(Sarocladium),枝孢霉属(Cladosporium),链格孢属(Alternaria)和青霉属(Penicillium)等。储藏年限不同,对应的优势菌属不同,其中曲霉属均是储藏期稻谷的优势菌属之一。 相似文献
4.
Ramzi A. Mothana Mansour S. Al-Said Nawal M. Al-Musayeib Ali A. El Gamal Shaza M. Al-Massarani Adnan J. Al-Rehaily Majed Abdulkader Louis Maes 《International journal of molecular sciences》2014,15(5):8360-8371
Chromatographic separation of the n-hexane extract of the aerial part of Plectranthus barbatus led to the isolation of five abietane-type diterpenes: dehydroabietane (1); 5,6-didehydro-7-hydroxy-taxodone (2); taxodione (3); 20-deoxocarnosol (4) and 6α,11,12,-trihydroxy-7β,20-epoxy-8,11,13-abietatriene (5). The structures were determined using spectroscopic methods including one- and two-dimensional NMR methods. Compounds (1)–(3) and (5) are isolated here for the first time from the genus Plectranthus. The isolated abietane-type diterpenes tested in vitro for their antiprotozoal activity against erythrocytic schizonts of Plasmodium falciparum, intracellular amastigotes of Leishmania infantum and Trypanosoma cruzi and free trypomastigotes of T. brucei. Cytotoxicity was determined against fibroblast cell line MRC-5. Compound (2) 5,6-didehydro-7-hydroxy-taxodone showed remarkable activity with acceptable selectivity against P. falciparum (IC50 9.2 μM, SI 10.4) and T. brucei (IC50 1.9 μM, SI 50.5). Compounds (3)–(5) exhibited non-specific antiprotozoal activity due to high cytotoxicity. Compound (1) dehydroabietane showed no antiprotozoal potential. 相似文献
5.
Libkind D Moliné M Sommaruga R Sampaio JP van Broock M 《Yeast (Chichester, England)》2011,28(8):619-627
The synthesis of the UV Absorbing compounds named mycosporines (MYCs) has been detected in a few basidiomycetous yeast groups. Conspicuous accumulation of mycosporine-glutaminol-glucoside (MGG) in yeasts requires photo-induction and its photoprotective function has been postulated. The distribution of the ability to produce MYCs appeared to be related to the yeast taxonomic affiliation. In view of the potential significance of MYCs in yeast taxonomy, we here studied the distribution of this trait among dimorphic basidiomycetes of the Pucciniomycotina. Of the 94 fungal species (377 strains and 33 genera) tested, almost half were MYC-positive and MGG was the main compound produced. MGG synthesis was observed for representatives of five of seven Pucciniomycotina classes, indicating that this trait is widely distributed in this group. MGG detection proved useful for the differentiation of species of the polyphyletic genera, such as Rhodotorula and Sporobolomyces, that are phylogenetically separated. MGG quantification and UV tolerance studies in Cystobasidiomycetes supported the idea that the habitat of origin of each strains is important in the level of MGG synthesis and that MYCs have a photoprotective function in yeasts. The taxonomic value of this trait in fungal systematics is discussed. 相似文献
6.
7.
Indian borage (Plectranthus amboinicus) was investigated for antifungal activity through agar well diffusion assay. Indian borage oil (IBO) was found to be effective against various fungi tested, as it inhibited the radial growth of mycelia and exhibited broad fungitoxic properties against Aspergillus flavus, Aspergillus niger, Aspergillus ochraceus CFR 221, Aspergillus oryzae, Candida versatilis, Fusarium sp. GF-1019, Penicillium sp., and Saccharomyces cerevisiae. The effective concentration of IBO on the growth of A. ochraceus in yeast extract sucrose medium was determined. IBO completely inhibited ochratoxin (OTA) production by the toxigenic strain A. ochraceus at 500 ppm. Also, the application of IBO at 100 mg/g in food samples resulted in inhibition of the growth of A. ochraceus in food systems such as groundnut, maize and poultry feed and no detectable amount of OTA was found at a high moisture level of 30%, even after seven days. IBO has the potential for use as a botanical fungitoxicant against fungal attack in stored food commodities. 相似文献
8.
由于天线在不同的子带进行扫描,星载扫描模式不能像条带模式那样,获得连续的方位向相位历史,利用条带模式高精度处理算法(如距离一多普勒算法)处理ScanSAR数据,通过在脉冲扫描间隔中填零,把扫描数据看成中间填零的相干脉冲串序列,等效成条带SAR数据,利用条带模式的处理算法进行成像。针对填零后的数据,数据量大,可以采用基于通用图形处理单元的并行处理技术,加快处理速度。对填零处理形成的栅瓣调制,通过滤波进行消除。这样处理的图像和条带模式的图像具有相同的辐射和几何分布特性,有效抑制扇贝效应带来的影响。对实测星栽ScansAR数据进行成像处理,试验结果表明该方法的有效性。 相似文献
9.
Biodeterioration potentials of bacteria isolated from used car engine lubricating oil were examined using both used and unused oils as substrate. Used oil served as a better substrate for growth of the bacteria than unused oil. The bacterial isolates were identified as Bacillus, Corynebacterium, Actinomyces, Micrococcus, Serratia, Citrobacter, Edwardsiella, Pseudomonas, Nocardia and Acinetobacter species. Fungal genera isolated from the oil were Cladosporium, Aspergillus, Cephalosporium, Mucor, Monosporium, Penicillium and the yeast Saccharomyces. Incubation of the bacteria at different temperatures for 48 hours showed that 100% grew at 30°C, 56% grew at 45°C, 44% grew at 55°C, 31% grew at 60°C while 25% grew at 70°C and survived at 80°C. These results indicate that lubricating oil in service is more prone to biodeterioration than unused oil. 相似文献
10.
K. Vagionas O. Ngassapa D. Runyoro K. Graikou O. Gortzi I. Chinou 《Food chemistry》2007,105(4):1711-1717
The volatiles from the aerial parts of edible plants growing in Tanzania, Leucas glabrata, Plectranthus laxiflorus, Salvia nilotica and Vernonia smithiana, were investigated by GC and GC/MS. Thirty-five compounds were identified from L. glabrata, representing 80.4% of the total oil; forty-three from P. laxiflorus (86.7%); twenty-four from S. nilotica (94.3%); and thirty-nine compounds from V. smithiana (92.9%). Among the identified components, menthone, (p + o)-cymene, trans-caryophyllene and caryophyllene oxide were found as the main ones. Furthermore, the essential oils were investigated for their antimicrobial activity as well as for their antiradical activity, through the DPPH method. Upon antimicrobial assays, the oil of V. smithiana showed very strong antimicrobial activity against Gram-positive bacteria, oral pathogens and pathogenic fungi; the oil of P. laxiflorus also exhibited strong activity, mostly against Gram-positive bacteria and especially oral pathogens, while L. glabrata showed strong activity against all assayed bacteria. The essential oil of S. nilotica appeared to have the most antioxidant activity but was almost inactive against all tested microorganisms. 相似文献