This study is part of the endeavor to construct a comprehensive DNA barcoding database for common seaweeds in China. Identifications of red seaweeds, which have simple morphology and anatomy, are sometimes difficult s...This study is part of the endeavor to construct a comprehensive DNA barcoding database for common seaweeds in China. Identifications of red seaweeds, which have simple morphology and anatomy, are sometimes difficult solely depending on morphological characteristics. In recent years, DNA barcode technique has become a more and more effective tool to help solve some of the taxonomic difficulties. Some DNA markers such as COI（cytochrome oxidase subunit I） are proposed as standardized DNA barcodes for all seaweed species. In this study, COI, UPA （universal plastid amplicon, domain V of 23S rRNA）, and ITS （nuclear internal transcribed spacer） were employed to analyze common species of intertidal red seaweeds in Qingdao （119.3°-121°E, 35.35°-37.09°N）. The applicability of using one or a few combined barcodes to identify red seaweed species was tested. The results indicated that COI is a sensitive marker at species level. However, not all the tested species gave PCR amplification products due to lack of the universal primers. The second barcode UPA had effective universal primers but needed to be tested for the effectiveness of resolving closely related species. More than one ITS sequence types were found in some species in this investigation, which might lead to confusion in further analysis. Therefore ITS sequence is not recommended as a universal barcode for seaweeds identification.展开更多
In VSF-OFCDM wireless communication, wireless channel is divided into component channels with the same frequency space according to the frequency, and the carriers on component channels are mutually orthogonal. When t...In VSF-OFCDM wireless communication, wireless channel is divided into component channels with the same frequency space according to the frequency, and the carriers on component channels are mutually orthogonal. When there are enough subcarriers, the bandwidth efficiency of the system is close to nyquist limit, which can ensure the utilization ratio of system frequency. Therefore, under the premise of ensuring orthogonal division of channels, the channels received a secondary division according to data rate requirements and power limit of business to make the frequency resource fully used and makes the total power minimal, which realizes the optimal distribution of wireless-communication system resources. The secondary division is represented by bit loading algorithm the best bit number of subcarrier allocation in symbol period. For the characteristics of wide-band multi-media services and granular division of VSF-OFCDM wireless communication, the subject proposes the idea of business-oriented subcarrier allocation, which means that the subcarriers are divided in symbol period with the business as the dominant. Based on the idea, the paper designs service-oriented bit loading algorithm of subcarrier, byte and power combined with distribution based on channel detection, and makes verification and performance analysis on the algorithm.展开更多
We study the thermal transport of few-layer graphene nanoribbons in the presence of the transversal pressure by using molecular dynamics simulations. It is reported that the pressure can improve the thermal conductivi...We study the thermal transport of few-layer graphene nanoribbons in the presence of the transversal pressure by using molecular dynamics simulations. It is reported that the pressure can improve the thermal conductivity of few-layer graphene nanoribbons. This improvement can reach 37.5% in the low temperature region. The pressure dependence of thermal conductivity is also investigated for different length, width and thickness of few-layer graphene. Our results provide an alternative option to tuning thermal conductivity of few-layer graphene nanoribbons, b-arthermore, it maybe indicate a so-called pressure-thermM effect in nanomaterials.展开更多
基金supported by the National Special Research Fund for Non-Profit Sector (Agriculture) (No. 200903030)the National Natural Science Foundation of China (No.41176135)
文摘This study is part of the endeavor to construct a comprehensive DNA barcoding database for common seaweeds in China. Identifications of red seaweeds, which have simple morphology and anatomy, are sometimes difficult solely depending on morphological characteristics. In recent years, DNA barcode technique has become a more and more effective tool to help solve some of the taxonomic difficulties. Some DNA markers such as COI（cytochrome oxidase subunit I） are proposed as standardized DNA barcodes for all seaweed species. In this study, COI, UPA （universal plastid amplicon, domain V of 23S rRNA）, and ITS （nuclear internal transcribed spacer） were employed to analyze common species of intertidal red seaweeds in Qingdao （119.3°-121°E, 35.35°-37.09°N）. The applicability of using one or a few combined barcodes to identify red seaweed species was tested. The results indicated that COI is a sensitive marker at species level. However, not all the tested species gave PCR amplification products due to lack of the universal primers. The second barcode UPA had effective universal primers but needed to be tested for the effectiveness of resolving closely related species. More than one ITS sequence types were found in some species in this investigation, which might lead to confusion in further analysis. Therefore ITS sequence is not recommended as a universal barcode for seaweeds identification.
文摘In VSF-OFCDM wireless communication, wireless channel is divided into component channels with the same frequency space according to the frequency, and the carriers on component channels are mutually orthogonal. When there are enough subcarriers, the bandwidth efficiency of the system is close to nyquist limit, which can ensure the utilization ratio of system frequency. Therefore, under the premise of ensuring orthogonal division of channels, the channels received a secondary division according to data rate requirements and power limit of business to make the frequency resource fully used and makes the total power minimal, which realizes the optimal distribution of wireless-communication system resources. The secondary division is represented by bit loading algorithm the best bit number of subcarrier allocation in symbol period. For the characteristics of wide-band multi-media services and granular division of VSF-OFCDM wireless communication, the subject proposes the idea of business-oriented subcarrier allocation, which means that the subcarriers are divided in symbol period with the business as the dominant. Based on the idea, the paper designs service-oriented bit loading algorithm of subcarrier, byte and power combined with distribution based on channel detection, and makes verification and performance analysis on the algorithm.
基金Supported in part by the National Natural Science Foundation of China under Grant Nos.11004082 and 11175067the Natural Science Foundation of Guangdong Province under Grant Nos.10451063201005249 and S201101000332the Fundamental Research Funds for the Central Universities,JNU under Grant Nos.21611437 and 50421288
文摘We study the thermal transport of few-layer graphene nanoribbons in the presence of the transversal pressure by using molecular dynamics simulations. It is reported that the pressure can improve the thermal conductivity of few-layer graphene nanoribbons. This improvement can reach 37.5% in the low temperature region. The pressure dependence of thermal conductivity is also investigated for different length, width and thickness of few-layer graphene. Our results provide an alternative option to tuning thermal conductivity of few-layer graphene nanoribbons, b-arthermore, it maybe indicate a so-called pressure-thermM effect in nanomaterials.
