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Pollinating fig wasp Ceratosolen solmsi adjusts the offspring sex ratio to other foundresses

Insect Science 2013年第2期20卷 228-234页

作者： hao-Yuan Hu Zhong-Zheng Chen Zi-feng Jiang Da-Wei Huang Li-Ming Niu Yue-guan Fu Key Laboratory of Biotic Environment and Ecological Safety in Anhui Province College of Life Sciences Anhui Normal University Wuhu Anhui Province China Department of Biology University of Maryland College Park Maryland USA Key Laboratory of Zoological Systematics and Evolution Institute of Zoology Chinese Academy of Sciences Beijing China Plant Protection College Shandong Agricultural University Tai'an Shandong Province China Environment and Plant Protection Institute Chinese Academy of Tropical Agricultural Sciences Danzhou Hainan Province China

Local mate competition theory predicts that offspring sex ratio in pollinating fig wasps is female-biased when there is only one foundress, and increased foundress density results in increased offspring sex ratio. Information of other foundresses and clutch size have been suggested to be the main proximate explanations for sex ratio adjustment under local mate competition. Our focus was to show the mechanism of sex ratio adjustment in a pollinating fig wasp, Ceratosolen solmsi Mayr, an obligate pollinator of the functionally dioecious fig, Ficus hispida Linn., with controlled experiments in the field. First, we obtained offspring from one pollinator and offspring at different oviposition sequences, and found that offspring sex ratio decreased with clutch size, and pollinators produced most of their male offspring at the start of bouts, followed by mostly females. Second, we found that offspring sex ratio increased with foundress density, and pollinators did adjust their offspring sex ratio to other females in the oviposition patches. We suggest that when oviposition sites are not limited, pollinators will mainly adjust their offspring sex ratio to other foundresses independent of clutch size changes, whereas adjusting clutch size may be used to adjust sex ratio when oviposition sites are limited.

关键词： behavior co-evolution local mate competition mutualism pollinating figwasp sex ratio adjustment

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Multi-objective reentry trajectory optimization method via GVD for hypersonic vehicles

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Journal of Systems Engineering and Electronics 2017年第4期28卷 732-744页

作者： Chaofang Hu Yue Xin hao feng School of Electrical Engineering and Automation Tianjin University Tianjin 300072 China

In the constrained reentry trajectory design of hypersonic vehicles, multiple objectives with priorities bring about more difficulties to find the optimal solution. Therefore, a multi-objective reentry trajectory optimization (MORTO) approach via generalized varying domain (GVD) is proposed. Using the direct collocation approach, the trajectory optimization problem involving multiple objectives is discretized into a nonlinear multi-objective programming with priorities. In terms of fuzzy sets, the objectives are fuzzified into three types of fuzzy goals, and their constant tolerances are substituted by the varying domains. According to the principle that the objective with higher priority has higher satisfactory degree, the priority requirement is modeled as the order constraints of the varying domains. The corresponding two-side, single-side, and hybrid-side varying domain models are formulated for three fuzzy relations respectively. By regulating the parameter, the optimal reentry trajectory satisfying priorities can be achieved. Moreover, the performance about the parameter is analyzed, and the algorithm to find its specific value for maximum priority difference is proposed. The simulations demonstrate the effectiveness of the proposed method for hypersonic vehicles, and the comparisons with the traditional methods and sensitivity analysis are presented.

关键词： hypersonic vehicle reentry trajectory design multi-objective optimization generalized varying domain direct collocation method

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Majorana zero mode in the vortex of an artificial topological superconductor

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Science China(Physics,Mechanics & Astronomy) 2017年第5期60卷 49-59页

作者： hao-Hua Sun Jin-feng Jia Key Laboratory of Artificial Structures and Quantum Control(Ministry of Education) Department of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

Majorana fermion （MF）, an exotic particle that is identical to its own antiparticle, was recently found in solid matter as a quasiparticle excitation, the Majorana zero mode （MZM）, in the vortex of an artificial topological superconductor （TSC）. This artificial TSC, first proposed by Fu and Kane in 2008, is a heterostructure made of a topological insulator BiETe3 and an s-wave superconductor NbSe2. This paper will briefly review the experimental progresses based on the Bi2Te3/NbSe2 heterostructure. All evidences are self-consistent and reveal that the MZM exists in the center of vortex. Those experimental results are also supported by theory. This finding is a milestone in the research ofMajorana fermions in solid state physics and a starting point of MZM＇s application in topological quantum computation.

关键词： Majorana fermion Majorana zero mode topological superconductor heterostructure vortex

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A comparative study for the impact performance of shaped charge JET on UHPC targets

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Defence Technology（防务技术） 2019年第4期15卷 506-518页

作者： hao Wu feng Hu Qin Fang Research Institute of Structural Engineering and Disaster Reduction College of Civil Engineering Tongji University Shanghai 200092 China Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education Tongji University Shanghai 200092 China Research Institute for National Defense Engineering of Academy of Military Sciences PLA Beijing 100091 China Amy Engineering University of PLA Nanjing 210007 China

With the development of two-stage munitions(a precursor shaped charge(SC)and a following kinetic energy projectile)to attack the hard concrete targets,as well as the increasing applications of ultra-high performance concrete(UHPC)in both civil and military protective structures,a comparative study on the impact performance of SC formed jet on UHPC target is performed experimentally and numerically at ***,a series of jet penetration/perforation test on the UHPC,45# steel and UHPC/45# steel composite targets are *** assessing the penetration depth and borehole(crater and tunnel)diameter,the influences of target material and configuration as well as the standoff distance of SC on the impact performance of jet are experimentally ***,by adopting the 2 D multi-material Arbitrary Lagrange-Euler(ALE)algorithm,Fluid-Structure Interaction(FSI)method and erosion algorithm implemented in the finite element code LS-DYNA,the formation and impact performance of jet in the present test are well ***,based on the validated numerical algorithms,constitutive models and the corresponding parameters,the influences of target material(UHPC,NSC and 45# steel),standoff distance,target configuration(stacked and spaced)and weight efficiency on the impact performance of jet are further *** derived conclusions could provide helpful references for evaluating the ballistic performance of jet and designing the protective structures.

关键词： Shaped charge jet Ultra-high performance concrete Penetration Perforation Numerical simulation

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K-theoretic classification of fermionic operator mixings in holographic conformal field theories

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Science Bulletin 2016年第14期61卷 1115-1125页

作者： Shih-hao Ho feng-Li Lin Department of Physics Taiwan Normal University

In this paper, we apply the K-theory scheme of classifying the topological insulators/superconductors to classify the topological classes of the massive multi-flavor fermions in anti-de Sitter(Ad S) space. In the context of Ad S/conformal field theory(CFT) correspondence, the multi-flavor fermionic mass matrix is dual to the pattern of operator mixing in the boundary CFT. Thus, our results classify the possible patterns of operator mixings among fermionic operators in the holographic CFT.

关键词： Topological insulators/superconductorsSPT phases AdS/CFT correspondence K-theoretical classification Bulk/Edgecorrespondence Holographic CFT

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Equivalent circuit and characteristic simulation of a brushless electrically excited synchronous wind power generator

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Frontiers of Mechanical Engineering 2017年第3期12卷 420-426页

作者： hao WANG fengge ZHANG Tao guan Siyang YU School of Electrical Engineering Shenyang University of TechnologyShenyang 110870 China

A brushless electrically excited synchronous generator （BEESG） with a hybrid rotor is a novel electrically excited synchronous generator. The BEESG proposed in this paper is composed of a conventional stator with two different sets of windings with different pole numbers, and a hybrid rotor with powerful coupling capacity. The pole number of the rotor is different from those of the stator windings. Thus, an analysis method different from that applied to conventional generators should be applied to the BEESG. In view of this problem, the equivalent circuit and electromagnetic torque expression of the BEESG are derived on the basis of electromagnetic relation of the proposed generator. The generator is simulated and tested experimentally using the established equivalent circuit model. The experimental and simulation data are then analyzed and compared. Results show the validity of the equivalent circuit model.

关键词： wind power brushless electrically excited synchronous generator hybrid rotor equivalent circuit

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Effective bias reduction methods for passive source localization using TDOA and GROA

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Science China(Information Sciences) 2013年第7期56卷 97-108页

作者： hao BenJian LI Zan QI PeiHan guan Lei State Key Laboratory of Integrated Services Networks Xidian University

For passive source localization based on both TDOA and GROA, this paper proposes two bias reduction methods for the well-known Weighted-Least-Squares (WLS) estimator. We first derive the passive source localization bias from the two-step algebraic closed-form solution. This bias is found to be considerably larger than the Maximum Likelihood Estimator (MLE) and limits the WLS estimator's practical applications. In this paper, We develop two methods to reduce the bias. The first one called Bias-Subtraction-Method (BSM) directly subtracts the expected bias from the solution of the WLS estimator, and the second one called Bias-Reduction-Method (BRM) imposes a constraint to the equation error formulation to improve the source location estimate. The noise covariance matrix must be known exactly in calculating the expected bias in BSM, and we only need to know the structure of it in BRM. For far-field sources localization when the noise is Gaussian and not too large, both of the two proposed methods can reduce the localization bias effectively and achieve the Cramér-Rao Lower Bound (CRLB) performance very well, and the BRM almost has the same performance as the MLE estimator. Simulations corroborate the performance of the two proposed methods.

关键词： source localization bias reduction Time Differences of Arrival (TDOA) Gain Ratios of Arrival (GROA) Cramér-Rao Lower Bound (CRLB)

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Effect of cerium addition on non-metallic inclusions in a high-carbon chromium bearing steel

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Journal of Iron and Steel Research International 2023年第11期30卷 2254-2266页

作者： hao Li Qiang Ren Li-feng Zhang State Key Lab of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao066004HebeiChina School of Mechanical Engineering Yanshan UniversityQinhuangdao066004HebeiChina School of Mechanical and Materials Engineering North China University of TechnologyBeijing100144China

Effects of varied levels of cerium(28×10-6,65×10^(-6) and 150×10^(-6))on inclusions in a high-carbon chromium bearing steel at different stages(before adding cerium,after adding cerium for 1,5,10 min and ingot)were studied using laboratory *** automatic scanning electron microscope system with energy-dispersive spectroscopy was used to analyze the amount,composition,size and morphology of inclusions in the steel at different *** the cerium content in the molten steel increased from 0 to 150×10^(-6),the evolution sequence of inclusions was as follows:Al_(2)O_(3)→CeAl11O18→CeAlO_(3)→Ce_(2)O_(2)*** 28×10^(-6) cerium was added,Al_(2)O_(3) inclusions were modified into CeAl_(11)O_(18) inclusions in the molten steel and then were further transformed into Al2O3 and CeAlO3 inclusions in the solid steel during *** the addition of 65×10^(-6) cerium,inclusions in the molten steel were modified into CeAlO_(3) and a small number of Ce2O2S *** the addition amount of cerium increased to 150×10^(-6),inclusions were transformed to Ce_(2)O_(2)*** size of inclusions in the molten steel decreased obviously with cerium *** the other hand,the size of inclusions increased during the cooling process in solid steels of No.1 steel(with 28×10^(-6) cerium)and No.2 steel(with 65×10^(-6) cerium).During the cooling process,unmodified MnS inclusions were precipitated in the solid steel of No.1 steel and wrapped outside the Al2O3 and CeAlO_(3) inclusions to form large complex *** the cooling process of No.2 steel,the inclusion size of CeAlO_(3) increased due to the collision and *** the No.3 steel(with 150×10^(-6) cerium),the average size of inclusions decreased rapidly and remained at a lower size during the cooling process,which was beneficial to improving the fatigue life of the steel.

关键词： Cerium Inclusion Transformation High-carbon chromium bearing steel Modification

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Cognitive Frequency Hopping Sequences

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Chinese Journal of Electronics 2016年第1期25卷 185-191页

作者： guan Lei LI Zan hao Benjian SI Jiangbo NING Ben State Key Laboratory of Integrated Service Networks School of Telecommunications EngineeringXidian University

Since the immutable conventional Frequency hopping(FH) sequence cannot keep high FH communication reliability in complex electromagnetic environment, we propose an algorithm that can generate high-performance Cognitive frequency hopping sequence(CFHS) for Cognitive frequency hopping(CFH) *** employing the pseudo-random perturbation mapping,the CFHS is generated by remapping the block cipher FH sequence with the adaptive frequency slot number and frequency gap. The CFHS inherits the great integrated performance and its parameters could change with the electromagnetic environment. The statistics properties of Markov and uniformity are analyzed based on the Markov process theory and probability theory. Simulation results show that CFHS outperforms the widely-used FH sequences on the performance of uniformity, randomness, Hamming correlation, complexity and sensitivity. The proposed CFHS could be extensively applied in high reliable CFH system.

关键词： Cognitive frequency hopping(CFH) Cognitive frequency hopping sequences(CFHS) Adaptive frequency slots number Adaptive wide gap

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Microstructure, morphology, crystallization and rheological behavior of impact polypropylene copolymer

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Science China Chemistry 2012年第5期55卷 698-712页

作者： SHANG-guan YongGang CHEN feng ZHENG Qiang Key Laboratory of Macromolecular Synthesis and Functionalization Ministry of EducationDepartment of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

Impact polypropylene copolymer (IPC), named polypropylene catalloy, not only possesses excellent impact property, but also presents good rigidity. Its superior performances result from the complicated composition and microstructure. In the present article, recent progress in the studies on microstructure, morphology, crystallization and rheological behavior of IPC is summarized, and findings of the authors and their collaborators are reported. In general, IPC is divided into three components, i.e., ethylene-propylene random copolymer (EPR), a series of different segment lengths ethylene-propylene copolymer (EbP) and propylene homopolymer. The reasonable macromolecular structures of EbP and a multilayered core-shell model of dispersed phase structure in IPC were proposed, in which the dispersed phase consists of an outer EbP shell, an inner EPR layer and an EbP core. It is found that the annealing at melt-state may lead to an abnormal phase inversion, and the phase inversion disappears when temperature cools down to room temperature. The cause of phase inversion is ascribed to the existence of EbP component, which results in the stronger activity of the dispersed phase. The crystalline structure and morphologic results confirm the formation of β-iPP in IPC. Furthermore, it is found that the ethylene content in IPC and cooling rate of the samples have an important influence on the formation of β-iPP. Based on the crystallization kinetics analyzed by Lauritzen-Hoffman theory, crystallization behavior of different IPC samples is discussed and it is proposed that the dilution effect of ethylene propylene copolymer has a more remarkable influence on surface nucleation than on crystal growth. In addition, annealing at high temperature can result in the changes of chain structure for IPC, and this instability is ascribed to the oxidative degradation and crosslink reaction mainly in iPP component.

关键词： microstructure morphology crystallization behavior rheological property impact polypropylene copolymer

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