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The Analysis and Comparison of the Needle-puncture Property of Four Types of Silkworm Cocoons
Qian Wang,Yan Zhang,Hao Chen,Rong Zhang,Xuhong Yang,Ping Wang,Pibo Ma 한국섬유공학회 2020 Fibers and polymers Vol.21 No.8
Silkworm cocoons display outstanding properties in many aspects, such as thermal protection, biocompatibilityand mechanical resistance and so on. In this paper, we focus on the puncture properties without detailed exploration of fourtypes of cocoons (three domesticated cocoon and Eri silkworm). Different sections, end and middle, as well as differentdirections, puncturing from inner and outer surface, of four types of aforementioned cocoons were systematically analyzedand compared. The results of present research show that the middle section exhibits a relatively greater needle-punctureresistance compare with end section for three B. mori silkworm cocoons. With regard to different puncture directions, fromexternal and internal surface, puncturing from internal surface exhibits a relatively higher needle-puncture load as well asfracture displacement tendencies compared with needle-puncture performance from external surface no matter in middle orend sections. Combining physical parameter assessment, statistical analysis and needle-puncture performance, this researchinspires a clear-cut frame to design a composite with high puncture resistance.
Tight Bounds and Invertible Average Error Probability Expressions over Composite Fading Channels
Qian Wang,Hai Lin,Pooi-Yuen Kam 한국통신학회 2016 Journal of communications and networks Vol.18 No.2
The focus in this paper is on obtaining tight, simplealgebraic-form bounds and invertible expressions for the averagesymbol error probability (ASEP) of M-ary phase shift keying(MPSK) in a class of composite fading channels. We employ themixture gamma (MG) distribution to approximate the signal-tonoiseratio (SNR) distributions of fading models, which includeNakagami-m, Generalized-K (KG), and Nakagami-lognormalfading as specific examples. Our approach involves using the tightupper and lower bounds that we recently derived on the GaussianQ-function, which can easily be averaged over the general MG distribution. First, algebraic-form upper bounds are derived on theASEP of MPSK for M > 2, based on the union upper boundon the symbol error probability (SEP) of MPSK in additive whiteGaussian noise (AWGN) given by a single Gaussian Q-function. Bycomparison with the exact ASEP results obtained by numerical integration,we show that these upper bounds are extremely tight forall SNR values of practical interest. These bounds can be employedas accurate approximations that are invertible for high SNR. Forthe special case of binary phase shift keying (BPSK) (M = 2),where the exact SEP in the AWGN channel is given as one GaussianQ-function, upper and lower bounds on the exact ASEP areobtained. The bounds can be made arbitrarily tight by adjustingthe parameters in our Gaussian bounds. The average of the upperand lower bounds gives a very accurate approximation of the exactASEP. Moreover, the arbitrarily accurate approximations forall three of the fading models we consider become invertible forreasonably high SNR.
Qian Wang,Heng Liu,Yi Liu,Yang Zhao,Rui He 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.2
Multiple solution problems for nonlinear rotor bearing systems (RBSs) are of great interest in research and industrial development; it is a challenge to detect multiple solution distributions for RBSs, especially for large-scale systems. This paper develops a heuristic search method for detecting multiple periodic solution branches of RBSs. In this method, differential equations of RBSs are first converted to algebraic equations by the harmonic balance (HB) method; a model reduction technique is employed to keep only nonlinear degrees of freedom (DOFs). A heuristic search method is developed to detect multiple solutions for RBSs, and multiple solution branches are obtained by numerical continuation. By applying the methodology to a four-DOF lumped parameter system and a rolling bearing rotor system, it is shown that the proposed numerical method can be employed to search multiple solution branches of RBSs efficiently. Meanwhile, isolated solution branch phenomena are observed.
Reliable Gain Scheduling Output Tracking Control for Spacecraft Rendezvous
Qian Wang,Anke Xue 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.1
This paper has proposed a discrete gain scheduling output tracking control method for the homing phase of the spacecraft rendezvous based on the parametric Lyapunov equation. Considering the actuator saturation, output tracking and the partial loss of thruster effectiveness, we establish a relative dynamic model based on CW equation and transform the orbital transfer control problem into a stabilization problem. The proposed gain scheduling approach is to improve the state convergence rate by increasing the introduced parameters gradually and remove the affect of the partial loss of thruster effectiveness. To obtain the designed controller, we only need to solve a nonlinear equation. Numerical simulations illustrate the usefulness and effectiveness of the proposed method.
Qian Wang 아시아테플 2019 The Journal of Asia TEFL Vol.16 No.4
A plethora of studies concerning second language acquisition have argued that collaborative output task, as a reading enhancement activity, is facilitative to promoting second language incidental vocabulary acquisition. However, how learner’s cognitive style indexed by field dependent (FD) or field independent (FI) mediates L2 incidental vocabulary learning and retention through collaborative output tasks in Chinese EFL context remains under-explored. Inviting a total of 120 Chinese university students as participants, this study investigated the effects of different collaborative output tasks on FI and FD Learners’ incidental vocabulary acquisition. The results showed that 1) collaborative written output task was more contributive to receptive lexical acquisition and retention for FD learners whereas FI learners were less susceptible to output collaborative task type; 2) regardless of learner’s cognitive style, collaborative written output task was superior over the oral output mode in productive lexical gains, but not in retaining lexical learning; 3) FI learners have advantages in L2 vocabulary learning, compared with their FD counterparts.
Qian Wang,Wenliang Qiu,Zhe Zhang 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.55 No.5
A model has been proposed that can predict the ultimate torsional strength of single-box multicell reinforced concrete box girder under combined loading of bending, shear and torsion. Compared with the single-cell box girder, this model takes the influence of inner webs on the distribution of shear flow into account. According to the softening truss theory and thin walled tube theory, a failure criterion is presented and a ultimate torsional strength calculating procedure is established for single-box multi-cell reinforced concrete box girder under combined actions, which considers the effect of tensile stress among the concrete cracks, Mohr stress compatibility and the softened constitutive law of concrete. In this paper the computer program is also compiled to speed up the calculation. The model has been validated by comparing the predicted and experimental members loaded under torsion combined with different ratios of bending and shear. The theoretical torsional strength was in good agreement with the experimental results.