Design of Linear Functional Noncircular Gear with High Contact Ratio Used in Continuously Variable Transmission

Continuously variable transmission(CVT)of noncircular gear has the technical advantages of large bearing capacity and high transmission efficiency.The key technology of CVT with noncircular gear has been broken through some countries,and is in the stage of deep application research.Although the characteristics and design methods of noncircular gear pairs have been continuously studied in China,the noncircular gear CVT is still in the preliminary exploration and research stage.The linear functional noncircular gear pair,whose transmission ratio is a linear function in the working section,to realize continuously variable transmission was the research object in this paper.According to the required transmission ratio in the working section,the transmission ratio function in the non-working section was constructed by using a polynomial.And then the influence of pitch curve parameters in the working section on which in the non-working section was also analyzed to obtain the pitch curve suitable for transmission of this gear pair.In addition,for improving the stability and bearing capacity of gear transmission,the noncircular gear pair transmission with high contact ratio was designed.Furthermore,the accurate value of the contact tooth length was calculated based on the gear principle and the characteristics of the involute tooth profile,from this the contact tooth length error was calculated by comparing the accurate value with its actual value obtained by the rolling experiment.Finally,an indirect method to verify the contact ratio by detecting the contact length error of the tooth profile was proposed.

Genome-wide characterization of alternative splicing in blood cells of COVID-19 and respiratory infections of relevance

Dear Editor,Alternative splicing of eukaryotic transcripts refers to the posttranscriptional process in which the coding regions(exons)of a precursor transcript are joined in different combinations through the removal or retention of non-coding intervening sequences(introns)to produce distinct mature messenger RNA(mRNA)transcripts and further generate one or more mature mRNAs(Lee and Rio,2015).Alternative splicing is revealed dysregulation in infectious diseases.Many pathogens hijack the splicing mechanism of host cells to complete their replications,accompanied by dysregulated innate immune response or cell damage,leading to the changes of alternative splicing landscape in host cells(Ashraf et al.,2019;Tomezsko et al.,2020;Kremsdorf et al.,2021).The regulation mechanism of alternative splicing by viral pathogens,such as hepatitis B virus(Duriez et al.,2017),human immunodeficiency virus 1(Tomezsko et al.,2020),Zika virus(Bonenfant et al.,2020)and enterovirus 71(Li et al.,2020),have been explored.