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Analysis and prediction of loudspeaker large-signal symptoms

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Science China(Physics,Mechanics & Astronomy) 2013年第7期56卷 1355-1360页

作者： HENG wei shen Yong XIA Jie feng ZiXin LIU Yunfeng Nanjing University Institute of Acoustics

Nonlinear lumped-parameter force factor Bl(x), stiffness Kms(x) and inductance Le(x) of electrodynamic loudspeakers change frequency responses and generate some nonlinear effects for large stimulus: harmonic and intermodulation distortion, DC component in diaphragm displacement, instability of vibration and jumping effects. By modeling the nonlinear system under large-signal conditions, relationship between the nonlinear parameters and large-signal behavior can be revealed and help to provide guidance to diagnose loudspeakers. Agreement between the measured and predicted responses of a real loudspeaker validates the modeling and enables new methods for loudspeaker diagnosis.

关键词： force factor stiffness inductance large-signal behavior

干湿交替灌溉与植物生长调节剂对水稻光合特性及内源激素的影响

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作物学报 2025年第1期51卷 174-188页

作者：赵黎明段绍彪项洪涛郑殿峰冯乃杰沈雪峰广东海洋大学滨海农业学院广东湛江524088 黑龙江省农业机械工程科学研究院绥化分院黑龙江绥化152054

为探明干湿交替灌溉与植物生长调节剂(plant growth regulators, PGRs)对水稻光合特性、内源激素及产量的影响。采用盆栽与大田相结合方式,以龙粳31为试验材料,设置轻干湿交替灌溉(MI)和重干湿交替灌溉(HI)2种灌溉处理,于分蘖盛期和剑... 详细信息

为探明干湿交替灌溉与植物生长调节剂(plant growth regulators, PGRs)对水稻光合特性、内源激素及产量的影响。采用盆栽与大田相结合方式,以龙粳31为试验材料,设置轻干湿交替灌溉(MI)和重干湿交替灌溉(HI)2种灌溉处理,于分蘖盛期和剑叶展叶期喷施已酸二乙氨基乙醇酯(diethylaminoethylcaproate,DA)、6-苄氨基腺嘌呤(6-benzylaminoadenine,BA)和BA(分蘖盛期)+DA(剑叶展叶期)3种PGRs,并设置清水对照,探究干湿交替灌溉、PGRs及互作下干物质积累、光合特性、内源激素及产量差异。结果表明,与HI相比, MI显著增加了抽穗后叶面积、叶面积指数、SPAD值及净光合速率,提高了剑叶与籽粒IAA、GA3和ZR含量,降低了ABA含量,增加了干物质积累及茎鞘物质转运能力,并在改善节间性状基础上增加了结实率、每穗粒数及粒重,增产5.30%(盆栽)和5.11%(大田)。与CK相比,喷施BA+DA显著提高了抽穗后剑叶净光合速率、干物质积累及茎鞘物质转运能力,提高了剑叶与籽粒IAA、GA3和ZR含量,增加了千粒重、结实率、收获指数、每穗粒数和粒重,增产6.60%(盆栽)和6.05%(大田),其次是BA。干湿交替灌溉与PGRs互作对叶面积指数、内源激素含量、每穗粒数及千粒重存在显著影响,其中MI×(BA+DA)处理更有助于维持抽穗后绿叶功能持续期,提高叶片SPAD值、叶面积、叶面积指数和净光合速率,增强干物质积累及茎鞘物质转运能力,提高叶片与籽粒IAA、GA3和ZR含量,促进同化物向籽粒输出,并在稳定穗数基础上增加了千粒重、每穗粒数和粒重,提高了结实率和收获指数,实现产量较其他处理及CK增幅3.17%~12.57%(盆栽)和3.14%~11.55%(大田),而HI×(BA+DA)处理可实现MI×CK产量效果。综上所述,干湿交替灌溉配合喷施BA+DA可作为本区域水稻高产高效生产环节中的一种节水化控栽培组合措施。

关键词：水稻干湿交替灌溉植物生长调节剂光合特性内源激素产量

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Photo‑Energized MoS_(2)/CNT Cathode for High‑Performance Li–CO_(2)Batteries in a Wide‑Temperature Range

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Nano-Micro Letters 2025年第1期17卷 160-175页

作者： Tingsong Hu Wenyi Lian Kang Hu Qiuju Li Xueliang Cui Tengyu Yao Laifa shen Jiangsu Key Laboratory of Materials and Technologies for Energy Storage College of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016People’s Republic of China

Li–CO_(2) batteries are considered promising energy storage systems in extreme environments such as Mars;however,severe performance degradation will occur at a subzero temperature owning to the sluggish reaction ***,a photo-energized strategy adopting sustainable solar energy in wide working temperature range Li–CO_(2) battery was achieved with a binder-free MoS_(2)/carbon nanotube(CNT)photo-electrode as *** unique layered structure and excellent photoelectric properties of MoS_(2) facilitate the abundant generation and rapid transfer of photo-excited carriers,which accelerate the CO_(2) reduction and Li_(2)CO_(3) decomposition upon *** illuminated battery at room temperature exhibited high discharge voltage of 2.95 V and mitigated charge voltage of 3.27 V,attaining superior energy efficiency of 90.2%and excellent cycling stability of over 120 *** at an extremely low temperature of−30℃,the battery with same electrolyte can still deliver a small polarization of 0.45 V by the photoelectric and photothermal synergistic mechanism of MoS_(2)/CNT *** work demonstrates the promising potential of the photo-energized wide working temperature range Li–CO_(2) battery in addressing the obstacle of charge overpotential and energy efficiency.

关键词： Li-CO_(2)batteries Photo-energized Wide operation-temperature Kinetics MoS_(2)

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企业家创业动因和障碍的主成分分析模型

沈阳工业大学学报 2003年第2期25卷 161-164页

作者：冯炜申恩平杭州商学院工商管理分院浙江杭州310027 沈阳工业大学管理学院辽宁沈阳110023

归集了新企业形成前期,企业家创业的动机和障碍,驱动因素主要有投资、创新、独立、地位、经济利益和市场机会;障碍因素主要是缺少资源、税费高、经营困难.并运用主成分分析模型,描述了准企业家的特征,以及两种因素的权重.

关键词：企业家创业动机创业障碍主成分分析模型行为指标

THE FINITE ELEMENT METHOD FOR SEMILINEARPARABOLIC EQUATIONS WITH DISCONTINUOUSCOEFFICIENTS

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Journal of Computational Mathematics 1999年第2期17卷 191-198页

作者： feng, H shen, LJ shenzhen Univ Normal Coll Shenzhen 518060 Peoples R China Inst Appl Phys & Computat Math Lab Computat Phys Beijing 100088 Peoples R China

In this paper we investigate the existence, uniqueness and regularity of the solution of semilinear parabolic equations with coefficients that are discontinuous across the interface, some prior estimates are obtained. A net shape of the finite elements around the singular points was designed in [7] to solve the linear elliptic problems, by means of that net, we prove that the approximate solution has the same convergence rate as that without singularity.

关键词： finite element semilinear parabolic equation discontinuous coefficients

Gas-solid reduction kinetic model of MgO-fluxed pellets

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International Journal of Minerals,Metallurgy and Materials 2014年第1期21卷 12-17页

作者： Qiang-jian Gao feng-man shen Xin Jiang Guo wei Hai-yan Zheng School of Materials and Metallurgy Northeastern University

The reduction process of MgO-fluxed pellets was investigated and compared with traditional acidic pellets in this paper. Based on the piston flow concept and experimental data, a kinetic model fitting for the gas-solid phase reduction of pellets in tubular reactors （blast furnace, BF） was built up, and the equations of reduction reaction rate were given for pellets. A series of reduction experiments of pellets were carried out to verify the model. As a result, the experimental data and calculated result were fitted well. Therefore, this model can well describe the gas-solid phase reduction process and calculate the reduction reaction rate of pellets. Besides, it can give a better explanation that the reduction reaction rate （reducibility） of MgO-fluxed pellets is better than that of traditional acidic pellets in BF.

关键词： ore pellets magnesia reduction kinetics blast furnaces

Effect of magnesia on the compressive strength of pellets

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International Journal of Minerals,Metallurgy and Materials 2014年第5期21卷 431-437页

作者： feng-man shen Qiang-jian Gao Xin Jiang Guo wei Hai-yan Zheng School of Materials and Metallurgy Northeastern University

The compressive strength of MgO-fluxed pellets was investigated before and after they were reduced. The porosity and pore size of green pellets, product pellets, and reduced pellets were analyzed to clarify how MgO affects the strength of the pellets. Experimental resuits show that when the MgO-bearing flux content in the pellets increases from 0.0wt% to 2.0wt%, the compressive strength of the pellets at ambient temperature decreases, but the compressive strength of the pellets after reduction increases. Therefore, the compressive strength of the pellets after reduction exhibits no certain positive correlation with that before reduction. The porosity and pore size of all the pellets （with different MgO contents） increase when the pellets are reduced. However, the increase in porosity of the MgO-fluxed pellets is relatively smaller than that of the traditional non-MgO-fluxed pellets, and the pore size range of the MgO-fluxed pellets is relatively narrower. The reduction swelling index （RSI） is a key factor for governing the compressive strength of the reduced pellets. An approximately reversed linear relation can be concluded that the lower the RSI, the greater the compressive strength of the reduced pellets is.

关键词： iron ore pellets compressive strength magnesia ore reduction swelling

Microstructure and nanoindentation hardness of shot-peened ultrafine-grained low-alloy steel

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Journal of Iron and Steel Research International 2019年第5期26卷 472-482页

作者： Xiao-wei feng Juan Xie Wen-ying Xue Yong-feng shen Hong-bo Wang Zhen-yu Liu Institute of Systems Engineering of China Academy of Engineering Physics Mianyang 621999 Sichuan China Key Laboratory for Anisotropy and Texture of Materials (MOE) School of Materials Science and Engineering Northeastern University Shenyang 110819 Liaoning China The State Key Lab of Rolling and Automation Northeastern University Shenyang 110819 Liaoning China

The effect of shot peening (SP) on microstructure and hardness of ultrafine-grained (UFG) low-alloy steel was investigated. With increasing shot-peening time from 0.5 to 1.5 h, grain size of UFG low-alloy steel decreases from 400 to 280 nm at surface whilst that of the layer with a depth of 160μm decreases from (230 ± 15) to (75 ± 5) nm. Interestingly, nanoindentation shows that hardness increases linearly with increasing the SP duration, reaching a value as high as (7.10 ± 0.1) GPa at the depth of 160 μm after the SP duration of 1.5 h. The thickness of the SP treated layer is measured as^300 μm. The Hall-Petch (H-P) relationship was established for the hardening layer. Correspondingly, abrasion resistance should be ~51% higher than that of as-prepared UFG low-alloy steel. As shown in SP processing, grain refinement is the key factor responsible for the strengthening of the studied steel.

关键词： Low-alloy steel Shot peening Grain refinement Nanoindentation Hardness

Fundamental influence of irreversible stress-strain properties in solids on the validity of the ramp loading method

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Matter and Radiation at Extremes 2024年第6期9卷 94-104页

作者： Jingxiang shen wei Kang Center for Applied Physics and Technology and College of EngineeringPeking UniversityBeijing 100871China

The widely used quasi-isentropic ramp loading technique relies heavily on back-calculation methods that convert the measured free-surface velocity profiles to the stress-density states inside the compressed *** back-calculation methods are based on one-dimensional isentropic hydrodynamic equations,which assume a well-defined functional relationship P(p)between the longitudinal stress and density throughout the entire flow ***,this kind of idealized stress-density relation does not hold in general,because of the complexities introduced by structural phase transitions and/or elastic-plastic *** and to what extent these standard back-calculation methods may be affected by such inherent complexities is still an unsettled ***,we present a close examination using large-scale molecular dynamics(MD)simulations that include the detailed physics of the irreversibly compressed solid *** back-calculate the stress-density relation from the MD-simulated rear surface velocity profiles and compare it directly against the stress-density trajectories measured from the MD simulation *** exist in the cases studied here,and these turn out to be related to the irreversibility between compression and *** and compression waves are observed to propagate with different sound velocities in some parts of the flow field,violating the basic assumption of isentropic hydrodynamic models and thus leading to systematic back-calculation *** particular,the step-like feature of the P(p)curve corresponding to phase transition may be completely missed owing to these *** kind of mismatch between inherent properties of matter and the basic assumptions of isentropic hydrodynamics has a fundamental influence on how the ramp loading method can be applied.

关键词： field. irreversible solids