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Isolation and characterization of a novel linear-plasmid phage from the sediment of the Mariana Trench

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Virologica Sinica 2022年第2期37卷 311-313页

作者： Yali Hao Siyuan Wang Mujie Zhang Qingxue Tang Canxing Meng Liping Wang Qilian Fan Yaxian Yan Xiang Xiao Huahua Jian State Key Laboratory of Microbial Metabolism Joint International Research Laboratory of Metabolic&Developmental SciencesSchool of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghai200240China Key Laboratory of Marine Genetic Resources Third Institute of OceanographyMinistry of Natural ResourcesXiamen361005China Shanghai Key Laboratory of Veterinary Biotechnology School of Agriculture and BiologyShanghai Jiao Tong UniversityShanghai200240China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai519082China

Dear Editor,Temperate bacteriophages are widely distributed in bacteria isolated from different natural environments(Howard-Varona et al.,2017).The phages normally lead to lysogenic infection and merge their genetic components into the bacterial chromosome.Among the temperate phages,linear plasmid phages are atypical because of their capability to reside in host cells as linear ds DNA with covalently closed ends,rather than being integrated in host genomes in the form of prophages(Ravin et al.,2000;Ravin,2011).

关键词： Trench linear characterization

linear stability theory with the equivalent spanwise wavenumber correction in 3D boundary layers

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Applied Mathematics and Mechanics(English Edition) 2019年第3期40卷 407-420页

作者： Runjie SONG Shaolong ZHANG Jianxin LIU Laboratory for High-Speed Aerodynamics Tianjin University Institute of Fluid Physics China Academy of Engineering Physics

The prediction on small disturbance propagation in complex three-dimensional(3D) boundary layers is of great significance in transition prediction methodology, especially in the aircraft design. In this paper, the linear stability theory(LST) with the equivalent spanwise wavenumber correction(ESWC) is proposed in order to accurately predict the linear evolution of a disturbance in a kind of boundary layer flow with a vital variation in the spanwise direction. The LST with the ESWC takes not only the scale of the mean flow with the significant variation but also the wavenumber evolution of the disturbance itself. Compared with the conventional LST, the results obtained by the new method are in excellent agreement with those of the numerical simulations. The LST with the ESWC is an effective method on the prediction of the disturbance evolution in 3D boundary layers, which improves the prediction of the LST in the applications to complex 3D boundary layers greatly.

关键词： three-dimensional(3D)boundary layer prediction of disturbance propagation equivalent spanwise wavenumber linear stability theory(LST) numerical simulation

linear Acceleration of an Undulatory Robotic Fish with Dynamic Morphing Median Fin under the Instantaneous Self-propelled Condition

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Journal of Bionic Engineering 2020年第2期17卷 241-253页

作者： Wenguang Sun Zemin Liu Ziyu Ren Gang Wang Tao Yuan Li Wen School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China AECC Hunan Aviation Powerplant Research Institute Zhuzhou 412000China

Fish commonly execute rapid linear accelerations initiated during steady swimming,yet the function of the median fins during this process is less understood.We find that the erection/folding time(from the starting time of the linear acceleration(0 s)to the starting time of the folding movement of the fin),as well as the spreading area of the median fins,actively change during the linearacceleration of the live largemouth bass(Micropterus salmoides).To better understand the influence of the folding time and the area change of the median fins on the linear acceleration,we implemented an undulatory biomimetic robotic fish with soft median fins that can be programmed to erect and fold,just like a live fish.To characterize the acceleration performance of the robotic fish,we developed a"self-propelled"experiment technique based on the Kalman filter and Proportional-Integral-Derivative(PID)control algorithm.The experiments on the robotic fish show the acceleration induced by fully-erected median fins increases by 46.3%.Fully-erected median fins positively contribute to propulsion primarily at the onset stage of the linear acceleration while result in a significant decrease in steady swimming speed by 25%,which suggests a large drag force is induced at the steady swimming stage due to the enlarged wetted area.Parametric sweeping experiments on erection/folding time and spreading area demonstrate a proper combination of the erection/folding time and the spreading area enhances the mean linear acceleration by up to 85%.Particle Image Velocimetry(PIV)results reveal that the vortexes shed by the erected dorsal fin are stronger than those shed by the folded fin.As the acceleration process progresses,the thrust generated by the dorsal fins gradually is weakened until only resistance is generated in the end.Our findings may shed light on the realization of controllable surfaces on high performance fish-inspired robotic systems in the future.

关键词： robotic fish linear acceleration median fin instantaneous self-propelled system

linear complexity and autocorrelation of a new class of binary generalized cyclotomic sequences of order two and length pqr

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Journal of Systems Engineering and Electronics 2019年第4期30卷 651-661页

作者： JIA Wenjuan GAO Juntao ZHANG Peng School of Telecommunications Engineering Xidian UniversityXi’an 710071China The State Key Laboratory of Integrated Services Network Xidian UniversityXi’an 710071China

Cyclotomic sequences have good cryptographic properties and are closely related to difference sets.This paper proposes a new class of binary generalized cyclotomic sequences of order two and length pqr.Its linear complexity,minimal polynomial,and autocorrelation are investigated.The results show that these sequences have a large linear complexity when 2∈D1,which means they can resist the Berlekamp-Massey attack.Furthermore,the autocorrelation values are close to 0 with a probability of approximately 1?1/r.Therefore,when r is a big prime,the new sequence has a good autocorrelation.

关键词： generalized cyclotomic sequence linear complexity minimal polynomial autocorrelation value.

Monte Carlo sampling for error propagation in linear regression and applications in isochron geochronology

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Science Bulletin 2019年第3期64卷 189-197页

作者： Yang Li Shuang Zhang Richard Hobbs Camila Caiado Adam D.Sproson David Selby Alan D.Rooney State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Department of Earth Sciences Durham University Department of Geology and Geophysics Yale University Department of Mathematical Sciences Durham University Atmosphere and Ocean Research Institute The University of Tokyo

Geochronology is essential for understanding Earth's history. The availability of precise and accurate isotopic data is increasing; hence it is crucial to develop transparent and accessible data reduction techniques and tools to transform raw mass spectrometry data into robust chronological data. Here we present a Monte Carlo sampling approach to fully propagate uncertainties from linear regressions for isochron dating. Our new approach makes no prior assumption about the causes of variability in the derived chronological results and propagates uncertainties from both experimental measurements(analytical uncertainties) and underlying assumptions(model uncertainties) into the final age determination.Using synthetic examples, we find that although the estimates of the slope and y-intercept(hence age and initial isotopic ratios) are comparable between the Monte Carlo method and the benchmark‘‘Isoplot" algorithm, uncertainties from the later could be underestimated by up to 60%, which are likely due to an incomplete propagation of model uncertainties. An additional advantage of the new method is its ability to integrate with geological information to yield refined chronological constraints. The new method presented here is specifically designed to fully propagate errors in geochronological applications involves linear regressions such as Rb-Sr, Sm-Nd, Re-Os, Pt-Os, Lu-Hf, U-Pb(with discordant points),Pb-Pb and Ar-Ar.

关键词： linear regression Isochron Geochronology Uncertainty propagation Monte Carlo Isoplot

linear Codes with Two Weights or Three Weights from Two Types of Quadratic forms

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Transactions of Nanjing University of Aeronautics and Astronautics 2017年第1期34卷 62-71页

作者： Zhu Xiaoxing Xu Dazhuan Department of Mathematics Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China

Let F_qbe afinite field with q=pmelements,where pis an odd prime and mis apositive integer.Here,let D_0={(x_1,x_2)∈F_q^2\{(0,0)}:Tr(x_1^(pk1+1)+x_2^(pk2+1))=c},where c∈F_q,Tr is the trace function fromFF_qtoFpand m/(m,k_1)is odd,m/(m,k_2)is even.Define ap-ary linear code C_D =c(a_1,a_2):(a_1,a_2)∈F_q^2},where c(a_1,a_2)=(Tr(a_1x_1+a_2x_2))_((x1,x2)∈D).At most three-weight distributions of two classes of linear codes are settled.

关键词： linear codes weight distribution Gauss sum Weil sum

Adaptive linear Quadratic Regulator for Continuous-Time Systems With Uncertain Dynamics

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 833-841页

作者： Sumit Kumar Jha Shubhendu Bhasin IEEE Department of Electronics and Communication Engineering Motilal Nehru National Institute of Technology AllahabadPrayagraj-211004India Department of Electrical Engineering Indian Institute of Technology DelhiNew Delhi-110016India

In this paper, adaptive linear quadratic regulator(LQR) is proposed for continuous-time systems with uncertain dynamics. The dynamic state-feedback controller uses inputoutput data along the system trajectory to continuously adapt and converge to the optimal controller. The result differs from previous results in that the adaptive optimal controller is designed without the knowledge of the system dynamics and an initial stabilizing policy. Further, the controller is updated continuously using input-output data, as opposed to the commonly used switched/intermittent updates which can potentially lead to stability issues. An online state derivative estimator facilitates the design of a model-free controller. Gradient-based update laws are developed for online estimation of the optimal gain. Uniform exponential stability of the closed-loop system is established using the Lyapunov-based analysis, and a simulation example is provided to validate the theoretical contribution.

关键词： Adaptive optimal control continuous policy update linear quadratic regulator uncertain system dynamics

Identification of heavy metal-contaminated Tegillarca granosa using laser-induced breakdown spectroscopy and linear regression for classification

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Plasma Science and Technology 2020年第8期22卷 151-159页

作者：谢忠好孟留伟冯西安陈孝敬陈熙袁雷鸣石文黄光造衣铭 School of Marine Science and Technology Northwestern Polytechnical UniversityXi'an 710072People's Republic of China College of Physical and Electronic Information Engineering Wenzhou UniversityWenzhou 325035People's Republic of China Research and Development Department Hangzhou Goodhere Biotechnology Co.LtdHangzhou 311100People's Republic of China Research and Development Department Hangzhou Weizan Technology Co.LtdHangzhou 311100People's Republic of China

Tegillarca granosa(T.granosa)is susceptible to heavy metals,which may pose a threat to consumer health.Thus,healthy and polluted T.granosa should be distinguished quickly.This study aimed to rapidly identify heavy metal pollution by using laser-induced breakdown spectroscopy(LIBS)coupled with linear regression classification(LRC).Five types of T.granosa were studied,namely,Cd-,Zn-,Pb-contaminated,mixed contaminated,and control samples.Threshold method was applied to extract the significant variables from LIBS spectra.Then,LRC was used to classify the different types of T.granosa.Other classification models and feature selection methods were used for comparison.LRC was the best model,achieving an accuracy of 90.67%.Results indicated that LIBS combined with LRC is effective and feasible for T.granosa heavy metal detection.

关键词： shellfish laser-induced breakdown spectrometry heavy metal linear regression classification

Robust Admissibility and Stabilization of Uncertain Singular Fractional-Order linear Time-Invariant Systems

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IEEE/CAA Journal of Automatica Sinica 2019年第3期6卷 685-692页

作者： Saliha Marir Mohammed Chadli IEEE University Mohamed Boudiaf USTO University of Picardie Jules Verne

This paper addresses the robust admissibility problem in singular fractional-order continuous time systems. It is based on new admissibility conditions of singular fractional-order systems expressed in a set of strict linear matrix inequalities(LMIs). Then, a static output feedback controller is designed for the uncertain closed-loop system to be admissible. Numerical examples are given to illustrate the proposed methods.

关键词： Control fractional-order systems linear matrix inequalities (LMIs) output feedback control robust admissibility singular systems uncertain systems