PD-like finite time controller with simple structure for satellite attitude control

A finite time controller with PD-like structure for satellite attitude control is proposed in this paper.The controller is constructed with simple structure based on standard PD controller.The fractional order term is designed hence system could both have strong robustness and finite time convergence rate,and the advantage of finite time control and PD control is combined in this paper.System convergence rate is discussed by Lyapunov method,and the constraint on control parameters is given by implementing the coupled term of angular velocity and attitude quaternion.Moreover,the accuracy at steady stage depending on control parameters is given hence system could converge to this field within finite time.System stability and performance is demonstrated by numerical simulation results.

LOCAL INFLUENCE ASSESSMENT IN A MULTIVARIATE t-MODEL WITH RAO'S SIMPLE STRUCTURE

The local influence analysis is an important problem in statistical inference and some models have been discussed in many literatures This paper deals with the problem of assessing local influences in a multivariate t-model with Rao's simple struc-ture(RSS). Based on Cook's likelihood displacement, the effects of some minor perturbation on the statistical inference is assessed. As an application, a common covariance-weighted perturbation is thoroughly discussed.

ASSESSMENT OF LOCAL INFLUENCE IN A GROWTH CURVE MODEL WITH RAO'S SIMPLE COVARIANCE STRUCTURE

The present paper deals with the problem of assessing the local influence in a growth curve model with Rao's simple covariance structure. Based on the likelihood displacement,the curvature measure is employed to evaluate the effects of some minor perturbations on the statistical inference, thus leading to the large curvature direction, which is the most critical diagnostic statistic in the context of the local influence analysis. As an application, the common covariance-weighted perturbation scheme is thoroughly considered.

Genetic Diversity and Population Structure in Landraces and Improved Rice Varieties from India

A set of 50 rice genotypes comprising landraces, local selections, and improved varieties were characterized using simple sequence repeat（SSR） and inter simple sequence repeat（ISSR） markers to study genetic diversity and population structure. Following unweighted pair group method with arithmetic mean based clustering using binary data of polymorphic markers, the genotypes were grouped into 5 clusters and 11 sub-clusters, whereas population structure analysis separated 50 rice genotypes into 5 sub-populations. Grouping of rice genotypes showed better resemblance with the pedigree information of the genotypes. Both genetic diversity and population structure analysis separated majority of the improved varieties from landraces and local selections. Some of the SSR markers amplified unique alleles which were specific to a particular genotype and could distinguish them from the rest. The results indicate that these rice genotypes exhibit a higher genetic diversity and can be very useful in rice improvement program.

Evolutionary Trend and Asymmetric Evolution of Living Things

The evolutionary trend of organisms, which often evolved from a simpler structure to a more complex structure, is a mystery. It seems that the later living things appeared on the earth, the more complex their structures were. This study pointed out that the evolutionary trend of organisms was the result of the organisms＇ asymmetric evolution-the phenomenon which the partition of the more complex structure was actually larger than that of the simpler structure on the same evolutionary platform of organisms, it explained the cause of the asymmetric evolution and listed much important evidence for organisms＇ asymmetric evolution.

Novel compact and lightweight coaxial C-band transit-time oscillator

Compactness and miniaturization have become increasingly important in the development of high-power microwave devices.Based on this rising demand,a novel C-band coaxial transit-time oscillator(TTO)with a low external guiding magnetic field is proposed and analyzed.The proposed device has the following advantages:simple structure,short axial length,high power conversion efficiency,and low external guiding magnetic field,which are of great significance for developing the compact and miniaturized high-power microwave devices.The application of a shorter axial length is made possible by the use of a transit radiation mechanism.Also,loading the opening foil symmetrically to both ends of the buncher helps reduce the external magnetic field of the proposed device.Unlike traditional foils,the proposed opening foil has a circular-hole;therefore,the electron beam will not bombard the conductive foil to generate plasma.This makes it possible to realize long pulse and high repetition rate operation of the device in future experiments.Through numerical calculation and PIC particle simulation,the stability of the intense relativistic electron beam(IREB)and the saturation time of the device are improved by using the conductive foil.The voltage and current of the diode are 548 kV and 11.4 kA,respectively.Under a 0.4-T external guiding magnetic field,a C-band output microwave with a frequency of 4.27 GHz and power of 1.88 GW can be generated.The power conversion efficiency of the proposed device is about 30%.

345 GHz Band-Pass Filter Using Ultra-Precision Machining Technology

This paper presents a terahertz（THz）band-pass filter using ultra-precision machining technology based on Chebyshev filter prototype.This iris inductive window coupled waveguide filter was designed by using 8 resonant cavities with a center frequency of 345 GHz and a 7% bandwidth.The final design fulfills the desired specifications and presents the minimum insertion loss of 1.55 d B and the return loss of less than 15 d B at 345 GHz.The stop-band rejection is50 d B off the center frequency about 30 GHz,which means it has a good performance of high stop-band suppression.Compared with the recent development of THz filters,this filter possesses the characteristic of simple structure and is easy to machining.

Informative ISSR Markers Help Identify Genetically Distinct Accessions of Oryza rufipogon in Yield Improvement

Inter simple sequence repeat（ISSR） polymorphism was used to determine genetic diversity and phylogenetic relationships in 90 genotypes of wild and cultivated species of Oryza from different geographical regions of the world. In all the 17 primers used in ISSR-PCR, a total of 11 464 bands were amplified at 253 band positions/loci. The primer UBC-809 amplified the maximum bands（1 059） at 21 band positions. UBC-810 and UBC-835 amplified the minimum of 391 bands each at 7 and 14 band positions, respectively. The mean polymorphism information content ranged from 0.44 to 0.84 and resolving power ranged from 8.69 to 23.53. Un-weighted pair group method with arithmetic mean dendrogram and population structure based on the 17 primers separated all genotypes into 4 major clusters with a genetic similarity of 53%–100%. The first two clusters consisted of 30 O. rufipogon accessions each. In the third cluster, O. nivara and O. longistaminata grouped as one sub-cluster and all other O. nivara accessions and cultivars grouped as another sub-cluster. The fourth cluster had only five O. rufipogon accessions which can be a source of new genes. Four sub-populations were identified within O. rufipogon and two sub-populations within O. nivara at K = 7. A subset of six primers with high resolving power values were the most informative and grouped all genotypes almost similarly as the 17 primers did. Use of these six highly informative primers in ISSR-PCR is a cost effective and robust method for assessing genetic diversity in large germplasm collections of wild rice species.

triple-node motif signal amplification bistable system the Fitz Hugh–Nagumo neuron

It has been found that a triple-node feed-forward motif has a function of signal amplification, where two input nodes receive the external weak signal and jointly modulate the response of the third output node [Liang et al.,Phys. Rev. E 88（2013） 012910]. We here show that the signal amplification can be further enhanced by adding a link between the two input nodes in the feed-forward motif. We further reveal that the coupling strength of the link regulates the enhancement of signal amplification in the modified feed-forward motif. We finally analyze the mechanism of signal amplification of such simple structure.