Research on the feature of speech and image signals are carried out from two perspectives,the time domain and the frequency domain.The speech and image signals are a non-stationary signal,so FT is not used for the non...Research on the feature of speech and image signals are carried out from two perspectives,the time domain and the frequency domain.The speech and image signals are a non-stationary signal,so FT is not used for the non-stationary characteristics of the signal.When short-term stable speech is obtained by windowing and framing the subsequent processing of the signal is completed by the Discrete Fourier Transform(DFT).The Fast Discrete Fourier Transform is a commonly used analysis method for speech and image signal processing in frequency domain.It has the problem of adjusting window size to a for desired resolution.But the Fractional Fourier Transform can have both time domain and frequency domain processing capabilities.This paper performs global processing speech encryption by combining speech with image of Fractional Fourier Transform.The speech signal is embedded watermark image that is processed by fractional transformation,and the embedded watermark has the effect of rotation and superposition,which improves the security of the speech.The paper results show that the proposed speech encryption method has a higher security level by Fractional Fourier Transform.The technology is easy to extend to practical applications.展开更多
为探究氮素对药用植物三七[Panax notoginseng (Burkill) F. H. Chen]生长、光合特性及皂苷含量的影响,从而为氮肥合理施用提供理论依据,通过盆栽试验,研究不同氮添加水平(低氮0 kg·hm^-2,LN;中氮225 kg·hm^-2,MN;高氮450 kg&...为探究氮素对药用植物三七[Panax notoginseng (Burkill) F. H. Chen]生长、光合特性及皂苷含量的影响,从而为氮肥合理施用提供理论依据,通过盆栽试验,研究不同氮添加水平(低氮0 kg·hm^-2,LN;中氮225 kg·hm^-2,MN;高氮450 kg·hm^-2,HN)对二年生三七叶片解剖结构、根系形态特征、生物量、光合效率及皂苷含量的影响。结果表明:三七叶片的上表皮厚度、下表皮厚度、栅栏组织厚度和海绵组织厚度在HN水平下最大,总根长、主根长、根系表面积、须根数、须根长、根长密度、根质比、根冠比和比叶面积在LN水平下最大,MN水平根系活力显著高于其他氮素水平(P<0.05);光响应和CO_2响应过程中,MN处理的净光合速率、最大光合速率、羧化速率、最大电子传递速率和最大羧化速率均显著高于其他处理(P<0.05);单位叶面积氮含量、叶绿素含量和叶氮在光合组织中的分配量在HN处理下最大;光合氮素利用率在LN水平下最高,根部总氮含量在MN处理下最高;三七根的皂苷含量在HN处理下最低。缺氮和高氮均不利于三七生长,光合效率均降低,缺氮下的叶片变薄和高氮下的叶片增厚均能抑制CO_2的扩散;缺氮条件下,需产生更多保护自身生存的皂苷类防御物质;氮富余条件下,C/N比减少,则削弱皂苷的生物合成。展开更多
基金The work is supported by Regional Innovation Cooperation Project of Sichuan Province(Grant No.22QYCX0082)Jian-Guo Wei received the grant,and the Science and Technology Plan of Qinghai Province,China(Grant No.2019-ZJ-7012)Xiu Juan Ma received the grant.
文摘Research on the feature of speech and image signals are carried out from two perspectives,the time domain and the frequency domain.The speech and image signals are a non-stationary signal,so FT is not used for the non-stationary characteristics of the signal.When short-term stable speech is obtained by windowing and framing the subsequent processing of the signal is completed by the Discrete Fourier Transform(DFT).The Fast Discrete Fourier Transform is a commonly used analysis method for speech and image signal processing in frequency domain.It has the problem of adjusting window size to a for desired resolution.But the Fractional Fourier Transform can have both time domain and frequency domain processing capabilities.This paper performs global processing speech encryption by combining speech with image of Fractional Fourier Transform.The speech signal is embedded watermark image that is processed by fractional transformation,and the embedded watermark has the effect of rotation and superposition,which improves the security of the speech.The paper results show that the proposed speech encryption method has a higher security level by Fractional Fourier Transform.The technology is easy to extend to practical applications.
文摘为探究氮素对药用植物三七[Panax notoginseng (Burkill) F. H. Chen]生长、光合特性及皂苷含量的影响,从而为氮肥合理施用提供理论依据,通过盆栽试验,研究不同氮添加水平(低氮0 kg·hm^-2,LN;中氮225 kg·hm^-2,MN;高氮450 kg·hm^-2,HN)对二年生三七叶片解剖结构、根系形态特征、生物量、光合效率及皂苷含量的影响。结果表明:三七叶片的上表皮厚度、下表皮厚度、栅栏组织厚度和海绵组织厚度在HN水平下最大,总根长、主根长、根系表面积、须根数、须根长、根长密度、根质比、根冠比和比叶面积在LN水平下最大,MN水平根系活力显著高于其他氮素水平(P<0.05);光响应和CO_2响应过程中,MN处理的净光合速率、最大光合速率、羧化速率、最大电子传递速率和最大羧化速率均显著高于其他处理(P<0.05);单位叶面积氮含量、叶绿素含量和叶氮在光合组织中的分配量在HN处理下最大;光合氮素利用率在LN水平下最高,根部总氮含量在MN处理下最高;三七根的皂苷含量在HN处理下最低。缺氮和高氮均不利于三七生长,光合效率均降低,缺氮下的叶片变薄和高氮下的叶片增厚均能抑制CO_2的扩散;缺氮条件下,需产生更多保护自身生存的皂苷类防御物质;氮富余条件下,C/N比减少,则削弱皂苷的生物合成。
