The quotients between the (revised) Szeged index and Wiener index of graphs

Let $Sz(G),Sz^*(G)$ and $W(G)$ be the Szeged index, revised Szeged index and Wiener index of a graph $G.$ In this paper, the graphs with the fourth, fifth, sixth and seventh largest Wiener indices among all unicyclic graphs of order $n\geqslant 10$ are characterized; as well the graphs with the first, second, third, and fourth largest Wiener indices among all bicyclic graphs are identified. Based on these results, further relation on the quotients between the (revised) Szeged index and the Wiener index are studied. Sharp lower bound on $Sz(G)/W(G)$ is determined for all connected graphs each of which contains at least one non-complete block. As well the connected graph with the second smallest value on $Sz^*(G)/W(G)$ is identified for $G$ containing at least one cycle.Comment: 25 pages, 5 figure

New Requirements for English Majors in the Traditional Chinese Medicine Foreign Trade Industry in the New Era

In recent years, traditional Chinese medicine has shown a unique advantage in the treatment and recovery of infected patients, coupled with the gratifying situation of the import and export of traditional Chinese medicine products, and the vibrant prospects of the traditional Chinese medicine foreign trade market, the current situation of the traditional Chinese medicine foreign trade industry is quite promising. Therefore, the demand for Chinese medicine foreign trade talents by Chinese medicine foreign trade enterprises has greatly risen, which also puts forward new requirements for English majors. This paper analyzes the development trend of Chinese medicine cross-border e-commerce industry and the new requirements for English talents in the current era, discusses the necessary working ability and quality that English professionals engaged in Chinese medicine foreign trade must have in the current context, and expounds the main strategies and ways to improve the professional ability and work quality of Chinese medicine foreign trade professionals in the new era from multiple directions based on the practice of the project. This paper hopes to promote the development of the foreign trade industry of traditional Chinese medicine, and at the same time provide certain references for the cultivation of English professionals, and explore a new direction for the employment of English majors

2-tert-Butyl-4-chloro-5-[4-(2-fluoro­eth­oxy)benz­yloxy]pyridazin-3(2H)-one

In the title compound, C17H20ClFN2O3, the dihedral angle between the pyridazine and benzene rings is 41.37 (10)°. In the crystal, there are no significant intermolecular interactions present. The terminal –CH2F group is disordered over two sets of sites with an occupancy ratio of 0.737 (2):0.263 (2)

A survey of speech enhancement algorithms

speech is easy to be interfered by the external environment in real applications, resulting in the reduction of speech intelligibility and signal-to-noise ratio. In the past few decades, due to the wide application of speech based solutions in practical applications, speech enhancement of noisy speech signals has aroused considerable research interest. This paper classifi es and introduces several main speech enhancement methods, summarizes the advantages and disadvantages of several main methods, and fi nally puts forward the next research direction of speech enhancement methods

The Moore-Penrose inverse of 2 x 2 matrices over a certain *-regular ring

In this paper, we study representations of the Moore-Penrose inverse of a 2 x 2 matrix M over a *-regular ring with two term star-cancellation. As applications, some necessary and sufficient conditions for the Moore-Penrose inverse of M to have different types are given.This research is supported by the National Natural Science Foundation of China (11201063) and (11371089), the Specialized Research Fund for the Doctoral Program of Higher Education (20120092110020), the Foundation of Graduate Innovation Program of Jiangsu Province(CXLX13-072) and the Fundamental Research Funds for the Central Universities (22420135011), `FEDER Funds through "Programa Operacional Factores de Competitividade-COMPETE' and the Portuguese Funds through FCT-`Fundação para a Ciência e a Tecnologia', within the project PEst-OE/MAT/UI0013/2014