检索结果-南通市图书馆

Typical Frobenius Coverings

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2010年第11期26卷 2209-2214页

作者： Yan WANG rong quan FENG Jaeun LEE Department of Mathematics Yah Tai University Yah Tai 264005 P. R. China LMAM School of Mathematical Sciences Peking University Beijing 100871 P. R. China Department of Mathematics Yeungnam University Kyongsan 712-749 Korea

A covering p from a Cayley graph Cay（G, X） onto another Cay（H, Y） is called typical Frobenius if G is a Frobenius group with H as a Frobenius complement and the map p ： G →H is a group epimorphism. In this paper, we emphasize on the typical Frobenius coverings of Cay（H, Y）. We show that any typical Frobenius covering Cay（G, X） of Cay（H, Y） can be derived from an epimorphism /from G to H which is determined by an automorphism f of H. If Cay（G, X1） and Cay（G, X2） are two isomorphic typical Frobenius coverings under a graph isomorphism Ф, some properties satisfied by Фare given.

关键词： Frobenius group typical Frobenius covering isomorphic

Recovery of iron from Baotou rare earth tailings by magnetizing roast

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2013年第6期32卷 616-621页

作者： He Yang Yi rong rong Tang Xiang-Xin xue Yong Li School of Materials and Metallurgy Northeastern University

The difference of physicochemical properties among minerals in Baotou rare earth tailings is not significant,which leads to a great difficulty in separation of *** this article,the process of magnetizing roast and low-intensity magnetic separation was used to recover *** of calcination temperature,holding time and carbon/oxygen ratio on roasting efficiency was *** parameters evaluating magnetizing roast efficiency and theoretical value were determined.X-ray diffraction(XRD)analysis was used to investigate the conversion of Fe phase after *** results show that the best magnetizing roast conditions are calcination temperature of 650℃,holding time of 2.5 h,and carbon/oxygen molar ratio of *** best magnetization rate is 2.36,which is close to the theoretical value of *** on experiments of low-intensity magnetic separation under different intensities,the best current intensity is 2.0 A to obtain the best separation *** the best condition,the concentrate grade of iron is 45.45% and the recovery of iron is 68.36%.Most of rare earth,fluorine,and phosphorus are enriched in the magnetic separation *** XRD analysis shows that Fe exists in Fe2O3 before roasting and exists in Fe3O4after roasting.

关键词： Rare earth tailings Magnetizing roast Low-intensity magnetic separation

Synthesis of Polybutadienes with Controllable Microstructure by a Novel Binary Nd(3-NBSO_3)_3/Alkylaluminum Catalyst System

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2015年第3期33卷 475-480页

作者： Ji-qin Wen xue-quan Zhang 代全权 Key Laboratory of Synthetic Rubber Changchun Institute of Applied ChemistryChinese Academy of Sciences Jiangsu Province Institute for Medical Equipment Testing

The polymerization of 1,3-butadiene was examined by using a novel halogen-free neodymium m-nitrobenzenesulfonate （Nd（3-NBSOa）3·donors）/alkylaluminum binary catalyst system. The catalyst showed fairly high activity and controllable selectivity. The microstructure of the resultant polymer was adjustable by variation of electron donor and/or the alkylaluminum. ^13C-NMR and thermal analysis demonstrate that the produced polybutadienes have stereo-block chain structures of cis-1,4 and trans-1,4 segments with adjustable Tm and To. The neodymium sulfonate-based catalyst is believed to be significant in regulating the chain structure of polydienes and in exploring 1,3-diene polymerization mechanism.

关键词： Polybutadiene Microstructure Ziegler-Natta polymerization.

Real-time evaluation method of flight mission load based on sensitivity analysis of physiological factors

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2022年第3期35卷 450-463页

作者： Jun CHEN Lei xue Jia rong Xudong GAO School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710072China Department of Data Science and AI Monash UniversityClaytonVIC 3800Australia

As the complexity of flight missions continues to increase,sending a timely warning or providing assistance to pilots helps to reduce the probability of operational errors and flight *** pilots’physiological data,real-time evaluation of mission load is a feasible technical way to achieve *** this paper,a set of flight tasks including aircraft control,humancomputer interaction and mental arithmetic tests are designed to simulate five mission loads at different flight difficulty levels.A sensitivity analysis method based on a comprehensive test is proposed to select a set of sensitive physiological ***,based on the SVM hierarchical combination classification method,the pilot mission load real-time evaluation model is *** test results show significant differences in EMG,respiration rate(abdomen),heart rate,blood oxygen saturation,pupil area,fixation duration,number of fixations,and *** high accuracy obtained from experiments proved that the proposed real-time evaluation model is applicable to meet the requirements of real working *** findings can provide methodological references for mission load evaluation research in other fields.

关键词： Eye movement Mission load Physiological data Sensitivity analysis Support Vector Machine(SVM)

Two-Dimensional Animal-Like Fractals in Thin Films

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1996年第2期13卷 121-124页

作者： GAO Hong-jun xue Zeng-quan WU quan-de PANG Shi-jin Beijing Laboratory of Vacuum Physics Chinese Academy of SciencesBeijing 100080 Department of Radio-Electronics Peking UniversityBeijing 100871

we present a few unique animal-like fractal patterns in ionized-clnster-beam deposited fullerene-tetracyanoquinodimethane thin *** fractal patterns consisting of animal-like aggregates such as"fishes"and"quasi-seahorses"have been characterized by transnission electron *** results indicate that the sall aggregates ofthe aninmal-like body are composed of many single crystals whose crystalline directions are generally *** formation of tle fractal patterns can be attributed to the cluster-diffusion-lirnited aggregation.

关键词： aggregation fractal crystalline

Potential Symmetries to a System of Three-Component Nonlinear Diffusion Equations

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2006年第2期45卷 193-198页

作者： xue Chun-rong QU Chang-Zheng Center for Nonlinear Studies Northwest University Xi＇an 710069 China Department of Mathematics Northwest University Xi＇an 710069 China

A system of nonlinear diffusion equations with three components is studied via the potential symmetry method. It is shown that the system admits the potential symmetries for certain diffusion terms. The invariant solu... 详细信息

关键词： Lie point symmetry potential symmetry nonlinear diffusion equation group-invariant solutions

在线全文

学校读者我要写书评

暂无评论

杀菌条件对蓝点马鲛鱼脂质及风味品质的影响

渔业科学进展 2025年第1期46卷 222-230页

作者：王善宇简冲薛勇赵玲孙慧慧曹荣中国水产科学研究院黄海水产研究所山东青岛266071 青岛海洋科技中心海洋药物与生物制品功能实验室山东青岛266237 中国海洋大学食品科学与工程学院山东青岛266003

为探究不同杀菌条件对蓝点马鲛鱼(Scomberomorus niphonius)品质的影响,本文研究了110℃、46.4 min(A组),115℃、14.7 min(B组)和121℃、3.7 min(C组)3种杀菌条件对鱼肉感官品质、脂质组成及风味的影响。结果显示,杀菌后蓝点马鲛鱼的质... 详细信息

为探究不同杀菌条件对蓝点马鲛鱼(Scomberomorus niphonius)品质的影响,本文研究了110℃、46.4 min(A组),115℃、14.7 min(B组)和121℃、3.7 min(C组)3种杀菌条件对鱼肉感官品质、脂质组成及风味的影响。结果显示,杀菌后蓝点马鲛鱼的质地、滋味和气味的感官评分变化明显。样品中的总脂、甘油三酯和磷脂含量在杀菌后均显著降低(P<0.05),游离脂肪酸含量显著升高(P<0.05)。不同杀菌组间脂质组成存在差异,C组样品的脂质损失程度最高。脂质氧化程度受杀菌条件的影响显著(P<0.05),过氧化值(POV)含量均显著升高、硫代巴比妥酸反应值(TBARS)含量显著降低(P<0.05)。电子鼻分析结果表明,不同杀菌条件处理后鱼肉的气味特征明显不同。借助气相色谱-离子迁移谱从4组样品中鉴别出22种挥发性化合物,各组间的挥发性物质存在明显差异,其中,己醛、戊醛、异戊醛、3-戊酮、环己酮、3-羟基丁-2-酮和乙酸乙酯等是鱼肉中的主要风味物质,在B组样品中含量最高。综上,采用115℃、14.7 min(B组)杀菌的样品,其感官和风味品质明显优于其他组,且脂质氧化程度更低。研究结果可为蓝点马鲛鱼罐头产品加工提供参考。

关键词：蓝点马鲛鱼杀菌条件感官品质脂质挥发性物质风味

An efficient synthesis of ampicillin on magnetically separable immobilized penicillin G acylase

维普期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2010年第7期21卷 765-768页

作者： Ping xue Xiao Dan Song xue rong Cao Key Laboratory of Energy Resources&Chemical Engineering Ningxia UniversityYinchuan 750021China

Penicillin G acylase(PGA) was immobilized on the magnetic hydrophilic polymer microspheres with average pore size of 17.1 nm,specific surface area of 128.2 m2/g and saturate magnetization of 6.4 emu/*** 96.7%ampicillin yield with 1.60 of the synthesis/hydrolysis(S/H) ratio from 6-aminopenicillanic acid(6-APA) and D-(-)-alpha-phenylglycine methyl ester(D-PGME) can be achieved using the resultant magnetic biocatalyst in ethylene glycol,where only 82.1%yield with 1.40 of the S/H ratio was obtained using the free PGA under the identical reaction *** immobilized PGA can be separated magnetically and recycled for five times without obvious loss of its catalytic activity.

关键词： Immobilized penicillin G acylase Magnetic polymer microspheres Ampicillin synthesis Reusability

Genetic diversity and relatedness analysis of nine wild species of tree peony based on simple sequence repeats markers

在线全文

学校读者我要写书评

暂无评论

Horticultural Plant Journal 2021年第6期7卷 579-588页

作者： Yuqian xue rong Liu Jingqi xue Shunli Wang Xiuxin Zhang Institute of Vegetables and Flowers Chinese Academy of Agricultural SciencesBeijing 100081China Key Laboratory of Biology and Genetic Improvement of Horticultural Crops Ministry of Agriculture and Rural AffairsBeijing 100081China

Tree peony has nine wild species,but the evolutionary relationship of them is still ***,a total of 274 specimens from 22 natural populations of nine wild species were collected,and their genetic diversity and similarity was analyzed based on Simple Sequence Repeats(SSR)molecular markers.A total of 106 alleles were generated based on 20 primers and with an average of 5.3 alleles per ***’s information index(I)ranged from 0.6333 to 1.7842,and the average of Nei’s genetic diversity coefficient(H)was *** Information Content(PIC)value varied from 0.29 to 0.77,ten of these primers had high polymorphism(PIC≥0.50).All the above genetic parameters of primers reflect more rich genetic diversity information compared with other researches using SSR molecular markers to study the genetic diversity of tree peony wild *** the population level,the lowest and highest degree of genetic diversity occurred in Paeonia ludlowii-P1 and ***-P3 population,*** at species level,the genetic diversity of 9 wild peony species was as follows:***>***>***>***>***>***>***>***>***,cluster analysis at species level divided the nine wild tree peony species into two *** branch I,the closest phylogenetic relationship was found between *** and ***,followed by ***,***,and *** branch II,the closest relationship occurred between *** and ***,followed by *** and *** results supported the division of tree peonies into two subsects(Delavayanae and Vaginatae),it also supported *** and *** as independent *** results provided novel insight into the genetic diversity and phylogenetic relationship of nine wild tree peony *** will help formulate comprehensive protection measures of wild germplasm resources and select proper parents for distant hybridization in the future.

关键词： Tree peony Molecular marker Genetic diversity Phylogenetic relationship