On a Problem of Cameron’s on Inexhaustible Graphs

A graph G is inexhaustible if whenever a vertex of G is deleted the remaining graph is isomorphic to G. We address a question of Cameron [6], who asked which countable graphs are inexhaustible. In particular, we prove that there are continuum many countable inexhaustible graphs with properties in common with the infinite random graph, including adjacency properties and universality. Locally finite inexhaustible graphs and forests are investigated, as is a semigroup structure on the class of inexhaustible graphs. We extend a result of [7] on homogeneous inexhaustible graphs to pseudo-homogeneous inexhaustible graphs.The authors gratefully acknowledge support from the Natural Science and Engineering Research Council of Canada (NSERC).     

SYNTHESIS OF FUNCTIONAL MACROMOLECULE INTERMEDIATE THROUGH ACYLATION CATALYZED BY [Emim]Cl-AlCl3 IONIC LIQUID

Acylation reaction of anthracene with oxalyl chloride in the presence of [Emim]Cl-AlCl3 ionic liquid has been investigated. Pure 1,2-aceanthryenedione, which is used as intermediate of functional aromatic polymer material, was obtained by recrystalling the reaction mixture with aether and was determined by GC/MS, 1↑HNMR and FTIR analysis. The influences of various parameters, such as the contents of AlCl3 in [Emim]Cl-AlCl3, the amount of acylation agent, amount of [Emim]Cl-AlCl3, reaction temperature and reaction time were investigated. The optimum conditions were as follows： the molar fraction of AlCl3 in ionic liquid [x（AlCl3）] being 0.67, molar ratio of ionic liquid to anthracene being 2：1, molar ratio of oxalyl chloride to anthracene being 2：1, reaction temperature being 40℃ and reaction time being 6h. Under above conditions, the yield and selectivity of 1,2-aceanthrylenedione can reach 91.5% and 98.3% respectively. Further more, [Emim]Cl-AlCl3 ionic liquid, compared with metal halides such as AlCl3, was found to catalyze the reaction as a novel environmental friendly catalyst and solvent and can be reused.     

一种主链含非线性光学活性基团聚合物的合成

把非线性光学(NLO)发色基团引入到聚合物主链中,既可以增大聚合物中NLO基团的含量,从而提高聚合物的宏观NLO系数,又能够提高NLO聚合物的极化稳定性。本文报道一种由酚酞环氧树脂(PPh)与对硝基苯胺(NA)得到的NLO聚合物的合成及其极化松弛。 所用酚酞环氧树脂系自制,环氧值0.427。对硝基苯胺北京化工厂产,分析纯。N,N-二甲基甲酰胺为中国医药公司售品,化学纯,用前减压蒸馏精制,乙醇、丙酮均为北京化工厂生产,分析纯。在氮气保护下将等当量的PPh与NA溶于DMF中于150℃反应6～8小时后,倒     

Semi-interpenetrating polymer networks toward sulfonated poly(ether ether ketone) membranes for high concentration direct methanol fuel cell

Semi-IPNs were constructed by forming the crosslinking networks via the reaction between BPPO and diamine cross-linkers to overcome the dimensional swelling and methanol-permeation issues of SPEEK.     

Latoxanthin, a minor carotenoid isolated from the fruits of yellow paprika (Capsicum annuum var. lycopersiciforme flavum)

Latoxanthin was isolated as a minor carotenoid from the ripe fruits of yellow tomato shaped paprika (Capsicum annuum var. lycopersiciforme flavum) and identified as (all-E,3S,5R,6R,3′S,5′R,6′S)-5′,6′-epoxy-5,6,5′,6′-tetrahydro-β,β-carotene-3,5,6,3′-tetrol based on spectral data.     

B-值随机变量序列大数定律的收敛速度

设{X_n:n≥1}是在某可分Banach空间B上取值的独立随机变量序列,S_n=X_1+…+X_n,n≥1,对某00和>1,定义P_n(ε)=P(‖S_n‖/n~(1/p)≥ε)。本文的目的是研究当n→+∞时,P(ε)→0的速度,在Banach空间上推广了Heyde和Rohatgi的结果;同时,本文还讨论了P_n(ε)→0的速度与S_n/n~(1/p)→0 a.s.的关系问题。     

Different classification algorithms and serum surface enhanced Raman spectroscopy for noninvasive discrimination of gastric diseases

In this study, surface enhanced Raman spectroscopy (SERS) was used to investigate the spectral characteristics of blood serum for the purpose of diagnosing stomach diseases. SERS spectral data was collected from patients with atrophic gastritis, both pre‐operation and post‐operation gastric cancer, and from healthy individuals. Visual differences in the SERS spectra were observed between the four groups which indicate corresponding biomolecule concentration changes in blood. To further investigate the diagnostic ability of human serum, the spectral data was analyzed with three chemometric processes. These three methods extracted features and classified from the spectral data. Principal component analysis (PCA) was first performed to reduce the dimensionality of the original spectral data. Then, the classification methods support vector machine (SVM), linear discriminant analysis (LDA) and classification and regression tree (CART) were used for the evaluation of diagnostic ability. Accuracies of 96.5%, 88.8% and 87.1% were obtained for PCA‐SVM, PCA‐LDA and PCA‐CART, respectively. Copyright © 2016 John Wiley & Sons, Ltd.     

Crystalline ZnO thin film by hydrothermal growth

In this work, we have successfully synthesised ZnO crystal thin film with a high quality from hydrothermal reaction on sapphire substrate. The growth mechanism is clarified based on an extensive XTEM study. In addition, electrical and optical properties of the crystal thin film, which can be controlled by impurities, are characterized. The synthesis technique provides fairly high quality and cost-effective substrates for optoelectronic and renewable energy applications.