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Research on the Response Characteristics of Solenoid Valve of the Air-jet Loom by Simulation

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Journal of Thermal Science 2013年第6期22卷 606-612页

作者： jin Yuzhen DENG Ruoyu jin Yingzi HU Xudong Faculty of Mechanical Engineering & Automation Zhejiang Sci-Tech University

Solenoid valve is one of the executive parts of weft insertion control system. According to the response characteristics of the solenoid valve, an improved design becomes a necessity. Firstly, the numerical model was established after analyzing the solenoid valve during its start-up and shut-down. Comparing the simulation data with the practical data, it is verified that the numerical simulation model has a high feasibility. Secondly, excitation voltage and spring pre-compression were adjusted respectively, and the response rules after adjusting were investigated. The research of the study shows: the response time tends to be inverse proportional to the excitation voltage during start-up, and it becomes a constant value with the increase of the excitation voltage; the response time is proportional to the spring pre-compression when the solenoid valve starts up, it is inverse proportional to spring pre-compression when the solenoid valve shuts down. And the total response time is a constant value with the increase of the spring pre-compression. Therefore, the value of the excitation voltage and the spring pre-compression should be selected when the curve is becoming flatten. The results of the research can provide the reference to the further development of the solenoid valve.

关键词： Air-jet loom Solenoid valve Numerical simulation Response speed

Separability for Positive Operators on Tensor Product of Hilbert Spaces

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Acta Mathematica Sinica,English Series 2021年第6期37卷 893-910页

作者： jin Chuan HOU jin Fei CHAI College of Mathematics Taiyuan University of TechnologyTaiyuan 030024P.R.China

The separability and the entanglement(that is,inseparability)of the composite quantum states play important roles in quantum information ***,a quantum state is a trace-class positive operator with trace one acting on a complex separable Hilbert *** this paper,in more general frame,the notion of separability for quantum states is generalized to bounded positive operators acting on tensor product of Hilbert ***,not like the quantum state case,there are different kinds of separability for positive operators with different operator *** types of such separability are discussed;several criteria such as the finite rank entanglement witness criterion,the positive elementary operator criterion and PPT criterion to detect the separability of the positive operators are established;some methods to construct separable positive operators by operator matrices are *** may also make us to understand the separability and entanglement of quantum states better,and may be applied to find new separable quantum states.

关键词： Hilbert spaces tensor products positive operators separability entanglement

Method of adaptive PLL bandwidth adjustment without phase slipping

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Journal of Systems Engineering and Electronics 2014年第6期25卷 949-958页

作者： Yannian Lou Chaojie Zhang Xiaojun jin Zhonghe jin Micro-Satellite Research Center Zhejiang University

In a system based on the phase lock loop（PLL）, a trade-off must be made between the tracking precision and the dynamic performance if constant parameters are adopted. To overcome this drawback, a new method called no phase slipping adaptive bandwidth（NPS-AB） is proposed, which can adjust the loop bandwidth adaptively for different working conditions. As a result, both the tracking precision and the dynamic performance can be achieved concurrently. NPS-AB has two features to keep the loop stable： one is the capability of quick response to dynamics; the other is a series of additional constraints when the bandwidth is switched. Compared with other methods, there is no phase slipping during the adjustment process for NPS-AB. The phase integer ambiguity can be avoided and the phase value is kept valid. It is meaningful for carrier ranging systems. Simulation results show that NPS-AB can deal with sudden dynamics and keep the pseudo-range value stable in the entire dynamic process.

关键词： bandwidth adjustment tracking performance phase slipping adaptive loop

A class of weighted estimating equations for additive hazards models with covariates missing at random

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Science China Mathematics 2022年第3期65卷 583-602页

作者： jin jin Peng Ye Liuquan Sun Institute of Applied Mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Statistics University of International Business and EconomicsBeijing 100029China

Missing covariate data arise frequently in biomedical *** this article,we propose a class of weighted estimating equations for the additive hazards regression model when some of the covariates are missing at ***-specific and subject-specific weights are incorporated into the formulation of weighted estimating *** results are established for estimating selection probabilities that cover both parametric and non-parametric modelling *** resulting estimators have closed forms and are shown to be consistent and asymptotically *** studies indicate that the proposed estimators perform well for practical *** application to a mouse leukemia study is illustrated.

关键词： additive hazards model censored data kernel smoothing missing at random weighted estimating equation

Morphology evolution of two-phase Cu-Ag alloys under different conditions

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第3期10卷 458-463页

作者： jin-li HU jin-dong ZHANG Liang MENG Department of Materials Science and Engineering Zhejiang University Hangzhou 310027 China Xingtai Xinhui Copper Special Wire. Co. Ltd. Xingtai 055550 China

Cu-Ag filamentary microcomposites with different Ag contents were prepared by cold drawing and intermediate heat treatments. The microstructure characterization and filamentary distribution were observed for two-phase alloys under different conditions. The effect of heavy drawing strain on the microstructure evolution of Cu-Ag alloys was investigated. The results show that the microstructure components consist of Cu dendrites, eutectic colonies and secondary Ag precipitates in the alloys containing 6%-24% （mass fraction） Ag. With the increase in Ag content, the eutectic colonies in the microstructure increase and gradually change into a continuous net-like distribution. The Cu dendrites, eutectic colonies and secondary Ag precipitates are elongated in an axial direction and developed into the composite filamentary structure during cold drawing deformation. The eutectic colonies tend to evolve into filamentary bundles. The filamentary diameters decrease with the increase in drawing strain degree for the two-phase alloys, in particular for the alloys with low Ag content. The reduction in filamentary diameters becomes slow once the drawing strain has exceeded a certain level.

关键词： Cu-Ag alloy Microstructure Strain Filamentary composite

Lagrangian statistics in isotropic turbulent flows with deterministic and stochastic forcing schemes

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Acta Mechanica Sinica 2015年第1期31卷 25-31页

作者： jin-Cai Chen Guo-Dong jin Jian Zhang LNM Institute of MechanicsChinese Academy of Sciences

Artificial input of energy into the flow is neces sary to create and maintain a statistically stationary isotropic turbulence for sampling in studying the statistics. Due to the nonlinear coupling among different Fourier modes through the triadic interaction, whether or not various forc ing schemes affect the statistics in turbulence is an impor tant and open question. We present detailed comparison of Lagrangian statistics of fluids particles in forced isotropic turbulent flows in 1283, 2563, and 5123 simulations, with Taylorscale Reynolds numbers in the range of 64-171, us ing a deterministic and a stochastic forcing scheme, respec tively. Several Lagrangian statistics are compared, such as velocity and acceleration autocorrelations, and moments of Lagrangian velocity increments. The differences in the La grangian statistics obtained from the two forcing schemes are shown to be small, indicating that the isotropic forcing schemes used have little effects on the Lagrangian statistics in the isotropic turbulence.

关键词： Isotropic turbulence Deterministic forcingscheme Stochastic forcing scheme Lagrangian statisticalquantities

OPTIMAL DELAUNAY TRIANGULATIONS

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Journal of Computational Mathematics 2004年第2期22卷 299-308页

作者： LongChen jin-chaoXu MathematicsDepartment ThePennsylvaniaStateUniversityUniversityParkPA16802USA

The Delaunay triangulation, in both classic and more generalized sense, is studied in this paper for minimizing the linear interpolation error (measure in L^P-norm) for a given function. The classic Delaunay triangulation can then be characterized as an optimal triangulation that minimizes the interpolation error for the isotropic function ‖x‖^2 among all the triangulations with a given set of vertices. For a more general function, a functiondependent Delaunay triangulation is then defined to be an optimal triangulation that minimizes the interpolation error for this function and its construction can be obtained by a simple lifting and projection procedure. The optimal Delaunay triangulation is the one that minimizes the interpolation error among all triangulations with the same number of vertices, i.e. the distribution of vertices are optimized in order to minimize the interpolation error. Such a function-depend entoptimal Delaunay triangulation is proved to exist for any given convex continuous *** an optimal Delaunay triangulation associated with f, it is proved that △↓f at the interior vertices can be exactly recovered by the function values on its neighboring *** the optimal Delaunay triangulation is difficult to obtain in practice, the concept of nearly optimal triangulation is introduced and two sufficient conditions are presented for a triangulation to be nearly optimal.

关键词： Anisotropic mesh generation Delaunay triangulation Finite element Interpolation error Mesh quality N term approximation

Shor's algorithm does not factor large integers in the presence of noise

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Science China(Information Sciences) 2024年第7期67卷 305-320页

作者： jin-Yi CAI College of Letters and Science University of Wisconsin

We consider Shor's quantum factoring algorithm in the setting of noisy quantum gates. Under a generic model of random noise for(controlled) rotation gates, we prove that the algorithm does not factor integers of the form pq when the noise exceeds a vanishingly small level in terms of n—the number of bits of the integer to be factored, where p and q are from a well-defined set of primes of positive density. We further prove that with probability 1-o(1) over random prime pairs(p, q), Shor's factoring algorithm does not factor numbers of the form pq, with the same level of random noise present.

关键词： random noise Shor’s algorithm rotation gates quantum computing prime factorization

On the Martensitic Transformation Temperatures and Mechanical Properties of NiTi Alloy Manufactured by Selective Laser Melting: Effect of Remelting

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Acta Metallurgica Sinica(English Letters) 2021年第9期34卷 1223-1233页

作者： Jian-Bin Zhan Yan-jin Lu jin-Xin Lin College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350007China Key Laboratory of Optoelectronic Materials Chemistry and Physics Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

In this study, the infl uence of laser remelting on the relative density, martensitic transformation temperatures(MTTs), and mechanical properties of a NiTi alloy fabricated by selective laser melting(SLM) at a laser power between 15 and 75 W were investigated. A relative alloy density of approximately 99% was achieved in the power range of 45–60 W corresponding to the forming energy density range of 65.45–87.27 J/mm3. The MTTs increased with the increase in the energy density;thus, the initial contents of the B2 and B19′ phases of the SLM-produced NiTi alloy can be tailored by the utilized technique. However, the number of defects such as metallurgical pores and microcracks considerably increased at higher energy densities(> 87.27 J/mm3). Interestingly, the concentration of these defects was reduced by remelting in the energy density range of 21.82–65.45 J/mm3, while the alloy relative density increased to 99.7% ± 0.1% at a remelting energy density of 65.45 J/mm3. The results of tensile testing revealed that when the remelting energy was 75% or 100% of the forming energy input, the ultimate tensile strength and elongation of the alloy significantly increased. Therefore, the remelting strategy represents a promising route for manufacturing NiTi alloys with desired MTT ranges and mechanical properties.

关键词： Selective laser melting NiTi alloy Laser remelting Martensitic transformation temperature