Nigeria was listed as a part of terrorist states by United States of America as a result of Islamic group (Boko Haram Sect) attacks and other activities in the nation. It has also been discovered that the group emplo...Nigeria was listed as a part of terrorist states by United States of America as a result of Islamic group (Boko Haram Sect) attacks and other activities in the nation. It has also been discovered that the group employs “steganographic” schemes as a secure means for transmitting their hidden information to each other via Internet and social networks. The group has killed thousands of people since their increased insurgency in July, 2009. These challenges have affected the nation’s foreign policies, political and social economic developments. This research addresses the challenges by employing forensic technique using blind steganalysis approach to detect the presence of the hidden messages in images. Image Quality Metric is employed for extracting the features, and logistic regression is trained as the classifier to predict the stego-images. We show the effectiveness of the method by conducting test and analysis with 319 images varying in size and style. The result shows that the performance of the method is better than other steganalysis methods.展开更多
电感储能型脉冲电源是目前电磁发射技术的研究热点,提升装置储能密度对于推动电感储能型脉冲电源的应用和研究具有重要意义。本文介绍了一种适用于电感储能型脉冲电源的名为meat grinder with SECT的新电路,并对该电路进行了详细的原理...电感储能型脉冲电源是目前电磁发射技术的研究热点,提升装置储能密度对于推动电感储能型脉冲电源的应用和研究具有重要意义。本文介绍了一种适用于电感储能型脉冲电源的名为meat grinder with SECT的新电路,并对该电路进行了详细的原理分析,指出该电路兼具电流关断能力强和拓扑结构简单的优点。通过仿真将meat grinder with SECT和STRETCH meat grinder、STRETCH meat grinder with ICCOS这两种主流电路进行了性能比较,发现meat grinder with SECT电路在保持电气性能不变的同时,成本最低,体积最小。基于meat grinder with SECT电路,本文研制了50k J电感储能型脉冲电源并进行了试验测试,测试结果达到了预期目标。展开更多
Clematis sect. Atragene is revised in this paper based on the examination of a large number of herbarium specimens, extensive field observations, and morphometric analyses. Brief taxonomic history and geographical dis...Clematis sect. Atragene is revised in this paper based on the examination of a large number of herbarium specimens, extensive field observations, and morphometric analyses. Brief taxonomic history and geographical distribution of the section are given, the relationships among the species are discussed, and the evolutionary trends of some characters in the section are evaluated. The staminodes of the plants in this section may have evolved from the outer stamens with petaloid filaments and gradually disappearing anthers. Subsequently, they may have evolved in two different ways. One possibility is that the staminodes elongate and become lanceolate, as long as sepals, and their apices turn into attenuate. The other is that the staminodes are spathulate, but not elongating, as long as stamens, and their apices turn into retuse from obtuse and rounded. The evolutionary trend of sepals may be from thin to thick in texture, and the veins from non-prominent to prominent. As a result, five new series are established and nine species, two subspecies and nine varieties （including three new ranks） are recognized in this section. An identification key is provided, and each taxon is described and illustrated. Clematis sibirica and Clematis ochotensis are treated as subspecies of Clematis alpina due to their subtle differences and lack of, or few, overlapping distributions. Clematis fusijamana and Clematisfauriei are recognized as varieties of C. alpina ssp. ochotensis for the continuous variation of the velutinous strips on the sepal margins. Clematis iliensis is treated as variety of C. alpina ssp. sibirica for the continuous variation of leaf division types. Extensive variations in sepal color and basal caruncle size support degrading Clematis chiisanensis as a variety of Clematis koreana. The North American ser. Occientales may be primitive, whereas ser. Macropetalae may be the most advanced taxon in this section. Ser. Alpinae and ser. Koreanae are closely related to each other. However, the systematic position of ser. Tomentosae cannot be determined based on morphological characters alone in the present study.展开更多
The taxonomy of Lepisorus （J. Sm.） Ching sect. Lepisorus in China was revised based on herbarium specimen examinations, field observations, and microscopic study of rhizome scales, soral paraphyses, leaf epidermis, ...The taxonomy of Lepisorus （J. Sm.） Ching sect. Lepisorus in China was revised based on herbarium specimen examinations, field observations, and microscopic study of rhizome scales, soral paraphyses, leaf epidermis, and spores. As a result, nine species were recognized： Lepisorus macrosphaerus （Baker） Ching, Lepisorus asterolepis （Baker） Ching, Lepisorus marginatus Ching, Lepisorus kuchenensis （Y.C. Wu） Ching, Lepisorus megasorus （C. Chr.） Ching, Lepisorus kawakamii （Hayata） Tagawa, Lepisorus subsessilis Ching ＆ Y.X. Lin, Lepisorus affinis Ching, and Lepisorus nudus （Hook.） Ching. Lepisorus kawakamii （Hayata） Tagawa was reinstated; Lepisorus gyirongensis Ching ＆ S.K. Wu and Lepisorus longus Ching were reduced to synonyms ofL. nudus and L. affinis, respectively. The subdivision ofLepisorus macrosphaerus was not accepted. Rhizome scales and paraphyses are the most useful characters for species delimitation as well as for infrageneric classification. Characteristics of the leaf epidermis and spore ornamentation are usually stable and thus of great significance in understanding the relationships among groups within the genus.展开更多
Seventeen species, one subspecies and one variety of Dioscorea sect. Stenophora Uline were investi-gated for their phylogenetic relationships based on a sequence analysis of chloroplast matK and rbcL genes and trnL-F ...Seventeen species, one subspecies and one variety of Dioscorea sect. Stenophora Uline were investi-gated for their phylogenetic relationships based on a sequence analysis of chloroplast matK and rbcL genes and trnL-F intergenic spacer by maximum parsimony and maximum likelihood methods. The results showed that: (a) sect. Stenophora was a strongly supported monophyletic group; (b) D. rockii, D. membranacea, D. banzhuana, and D. simulans formed a moderately supported monophyletic group, and D. prazeri was weakly supported to be sister to this group; (c) D. althaeoides and D. nipponica ssp. nipponica formed a moderately supported clade, and D. nipponica ssp. rosthornii was not a member of this clade; (d) D. zingiberensis and D. sinoparviflora showed a moderate to strong sister relationship; and (e) D. collettii var. hypoglauca and D. collettii var. collettii were sister to each other, but with only weak support.展开更多
In this paper Clematis sect. Aspidanthera s.l. is revised. Seventy_ two species and 15 varieties are recognized. They are keyed, described, and in most cases illustrated, and are classified into six subsections. Of th...In this paper Clematis sect. Aspidanthera s.l. is revised. Seventy_ two species and 15 varieties are recognized. They are keyed, described, and in most cases illustrated, and are classified into six subsections. Of them, on e series, five species, and two varieties are described as new, and two new rank s are proposed. Brief taxonomic history and geographical distribution of the sec tion are given, the evolutionary trends of several important morphological characters observed are e numerated, and the relationships of its subsections are discussed. As a resul t, subsect. Dioicae, which shows striking resemblance in both habit an d floral structure to sect. Clematis subsect. Clematis, is regar ded as t he primitive group, while subsect. Insidiosae, bearing pistillate flower wit h erect sepals and no staminodes, is regarded as the advanced group within the s ection.展开更多
Vicia amirensis has pollen grain with swollen mesocipium, terete style, abaxially sprouting stylar hairs and globes stigma, differing from other five species,V. amoena, V. japonica, V. pseudo-orbus, V. ramuliflora, V....Vicia amirensis has pollen grain with swollen mesocipium, terete style, abaxially sprouting stylar hairs and globes stigma, differing from other five species,V. amoena, V. japonica, V. pseudo-orbus, V. ramuliflora, V. unijuga andV. venosa, in sect.Vicilla of Kupicha’s System. This result further support taxonomic treatmentV. amurensis proposed by Endo and Ohash. The chromosome numbers of 64 populations and karyotypes of 15 populations for sect.Vicilla and sect.Amurense were observed.V. amurensis andV. psendo-orbus have similar karyotype features such as the same karyotype symmetry, comparable chromosome size and the same type, of Sat-chromosomes, and thereforeV. amurensis in seet.Amurense is assumed to be closely related toV. japonica in sect.Vicilla. The primary study of nuclear DNA amount was carried out on nine populations of six taxa in sect.Vicilla in China. It is primarily discussed that evolutionary trend of karyotype, nuclear DNA amount in sect.Vicilla and geographic distribution of different ploidy cytotypes.展开更多
文摘Nigeria was listed as a part of terrorist states by United States of America as a result of Islamic group (Boko Haram Sect) attacks and other activities in the nation. It has also been discovered that the group employs “steganographic” schemes as a secure means for transmitting their hidden information to each other via Internet and social networks. The group has killed thousands of people since their increased insurgency in July, 2009. These challenges have affected the nation’s foreign policies, political and social economic developments. This research addresses the challenges by employing forensic technique using blind steganalysis approach to detect the presence of the hidden messages in images. Image Quality Metric is employed for extracting the features, and logistic regression is trained as the classifier to predict the stego-images. We show the effectiveness of the method by conducting test and analysis with 319 images varying in size and style. The result shows that the performance of the method is better than other steganalysis methods.
文摘电感储能型脉冲电源是目前电磁发射技术的研究热点,提升装置储能密度对于推动电感储能型脉冲电源的应用和研究具有重要意义。本文介绍了一种适用于电感储能型脉冲电源的名为meat grinder with SECT的新电路,并对该电路进行了详细的原理分析,指出该电路兼具电流关断能力强和拓扑结构简单的优点。通过仿真将meat grinder with SECT和STRETCH meat grinder、STRETCH meat grinder with ICCOS这两种主流电路进行了性能比较,发现meat grinder with SECT电路在保持电气性能不变的同时,成本最低,体积最小。基于meat grinder with SECT电路,本文研制了50k J电感储能型脉冲电源并进行了试验测试,测试结果达到了预期目标。
基金supported by the National Natural Science Foundation of China(Grant No.30870146).
文摘Clematis sect. Atragene is revised in this paper based on the examination of a large number of herbarium specimens, extensive field observations, and morphometric analyses. Brief taxonomic history and geographical distribution of the section are given, the relationships among the species are discussed, and the evolutionary trends of some characters in the section are evaluated. The staminodes of the plants in this section may have evolved from the outer stamens with petaloid filaments and gradually disappearing anthers. Subsequently, they may have evolved in two different ways. One possibility is that the staminodes elongate and become lanceolate, as long as sepals, and their apices turn into attenuate. The other is that the staminodes are spathulate, but not elongating, as long as stamens, and their apices turn into retuse from obtuse and rounded. The evolutionary trend of sepals may be from thin to thick in texture, and the veins from non-prominent to prominent. As a result, five new series are established and nine species, two subspecies and nine varieties （including three new ranks） are recognized in this section. An identification key is provided, and each taxon is described and illustrated. Clematis sibirica and Clematis ochotensis are treated as subspecies of Clematis alpina due to their subtle differences and lack of, or few, overlapping distributions. Clematis fusijamana and Clematisfauriei are recognized as varieties of C. alpina ssp. ochotensis for the continuous variation of the velutinous strips on the sepal margins. Clematis iliensis is treated as variety of C. alpina ssp. sibirica for the continuous variation of leaf division types. Extensive variations in sepal color and basal caruncle size support degrading Clematis chiisanensis as a variety of Clematis koreana. The North American ser. Occientales may be primitive, whereas ser. Macropetalae may be the most advanced taxon in this section. Ser. Alpinae and ser. Koreanae are closely related to each other. However, the systematic position of ser. Tomentosae cannot be determined based on morphological characters alone in the present study.
基金supported by the National Natural Science Foundation of China(Grant Nos.30470139 and 30770166).
文摘The taxonomy of Lepisorus （J. Sm.） Ching sect. Lepisorus in China was revised based on herbarium specimen examinations, field observations, and microscopic study of rhizome scales, soral paraphyses, leaf epidermis, and spores. As a result, nine species were recognized： Lepisorus macrosphaerus （Baker） Ching, Lepisorus asterolepis （Baker） Ching, Lepisorus marginatus Ching, Lepisorus kuchenensis （Y.C. Wu） Ching, Lepisorus megasorus （C. Chr.） Ching, Lepisorus kawakamii （Hayata） Tagawa, Lepisorus subsessilis Ching ＆ Y.X. Lin, Lepisorus affinis Ching, and Lepisorus nudus （Hook.） Ching. Lepisorus kawakamii （Hayata） Tagawa was reinstated; Lepisorus gyirongensis Ching ＆ S.K. Wu and Lepisorus longus Ching were reduced to synonyms ofL. nudus and L. affinis, respectively. The subdivision ofLepisorus macrosphaerus was not accepted. Rhizome scales and paraphyses are the most useful characters for species delimitation as well as for infrageneric classification. Characteristics of the leaf epidermis and spore ornamentation are usually stable and thus of great significance in understanding the relationships among groups within the genus.
文摘Seventeen species, one subspecies and one variety of Dioscorea sect. Stenophora Uline were investi-gated for their phylogenetic relationships based on a sequence analysis of chloroplast matK and rbcL genes and trnL-F intergenic spacer by maximum parsimony and maximum likelihood methods. The results showed that: (a) sect. Stenophora was a strongly supported monophyletic group; (b) D. rockii, D. membranacea, D. banzhuana, and D. simulans formed a moderately supported monophyletic group, and D. prazeri was weakly supported to be sister to this group; (c) D. althaeoides and D. nipponica ssp. nipponica formed a moderately supported clade, and D. nipponica ssp. rosthornii was not a member of this clade; (d) D. zingiberensis and D. sinoparviflora showed a moderate to strong sister relationship; and (e) D. collettii var. hypoglauca and D. collettii var. collettii were sister to each other, but with only weak support.
文摘In this paper Clematis sect. Aspidanthera s.l. is revised. Seventy_ two species and 15 varieties are recognized. They are keyed, described, and in most cases illustrated, and are classified into six subsections. Of them, on e series, five species, and two varieties are described as new, and two new rank s are proposed. Brief taxonomic history and geographical distribution of the sec tion are given, the evolutionary trends of several important morphological characters observed are e numerated, and the relationships of its subsections are discussed. As a resul t, subsect. Dioicae, which shows striking resemblance in both habit an d floral structure to sect. Clematis subsect. Clematis, is regar ded as t he primitive group, while subsect. Insidiosae, bearing pistillate flower wit h erect sepals and no staminodes, is regarded as the advanced group within the s ection.
文摘Vicia amirensis has pollen grain with swollen mesocipium, terete style, abaxially sprouting stylar hairs and globes stigma, differing from other five species,V. amoena, V. japonica, V. pseudo-orbus, V. ramuliflora, V. unijuga andV. venosa, in sect.Vicilla of Kupicha’s System. This result further support taxonomic treatmentV. amurensis proposed by Endo and Ohash. The chromosome numbers of 64 populations and karyotypes of 15 populations for sect.Vicilla and sect.Amurense were observed.V. amurensis andV. psendo-orbus have similar karyotype features such as the same karyotype symmetry, comparable chromosome size and the same type, of Sat-chromosomes, and thereforeV. amurensis in seet.Amurense is assumed to be closely related toV. japonica in sect.Vicilla. The primary study of nuclear DNA amount was carried out on nine populations of six taxa in sect.Vicilla in China. It is primarily discussed that evolutionary trend of karyotype, nuclear DNA amount in sect.Vicilla and geographic distribution of different ploidy cytotypes.
