基于磁致伸缩式超声导波测温技术基础研究

温度是科学研究中最普遍的物理量,也是生产精密仪器的重要参数,然而国内对于高温环境除热电偶测温传感器外尚无可靠的原位测试方法。依据超声导波测温的原理,设计出一套基于磁致伸缩效应的超声导波测温装置,测试了该装置在常温以及常温(12℃)~600℃的运行情况。实验表明,该装置可以在高温环境下稳定运行,并且得到常温(12℃)~600℃范围内的起始声波和端面回波之间时间间隔△t与介质温度之间的对应关系,为2 000℃以上的高温测量奠定了基础。     

和谐理念的渊源及其当代阐释

和谐理念源远流长。《周易》是中国和谐思维的源头;和谐理念具有深层的气论根源——气化谐和;儒家的"和而不同"理念影响深远。西方的和谐理念深受毕达哥拉斯、赫拉克利特及黑格尔的深远影响。和谐理念是一种认识论和方法论,其内涵随时代的发展而不断丰富和完善。     

Monitoring and Prediction of the Vibration Intensity of Seismic Waves Induced in Underwater Rock by Underwater Drilling and Blasting

All underwater drilling and blasting operations generate seismic waves.However,due to a lack of suitable vibration sensing instruments,most studies on the propagation of seismic waves have been limited to shorelines near construction areas or wharfs,whereas comparatively few studies have been conducted on the larger seafloor itself.To address this gap,a seafloor vibration sensor system was developed and applied in this study that consists of an autonomous acquisition storage terminal,soft-ware platform,and hole-plugging device that was designed to record the blasting vibration intensities received through submarine rocks at a given measurement point.Additionally,dimensional analyses were used to derive a predictive equation for the strength of blast vibrations that considered the in-fluence of the water depth.By combining reliable vibration data obtained using the sensor system in submarine rock and the developed predictive equation,it was determined that the water depth was an important factor influencing the measured vibration strength.The results using the newly derived equation were compared to those determined using the Sadowski equation,which is commonly used on land,and it was found that predictions using the derived equation were closer to the experimental values with an average error of less than 10％,representing a significant improvement.Based on these results,the developed sensor system and preliminary theoretical basis was deemed suitable for studying the propagation behavior of submarine seismic waves generated by underwater drilling and blasting operations.     

Designing rewards-based crowdfunding campaigns for strategic (but distracted) contributors

In rewards-based crowdfunding, entrepreneurs solicit donations from a large number of individual contributors. If total donations exceed a prespecified funding target, the entrepreneur distributes nonmonetary rewards to contributors; otherwise, their donations are refunded. We study how to design such campaigns when contributors choose not just whether to contribute, but also when to contribute. We show that strategic contribution behavior—when contributors intentionally delay until campaign success is likely—can arise from the combination of nonrefundable (potentially very small) hassle costs and the risk of campaign failure, and can explain pledging patterns commonly observed in crowdfunding. Furthermore, such delays do not hurt the entrepreneur if contributors are perfectly rational, but they do if contributors are distracted, that is, if they might fail to return to the campaign after an intentional delay. To mitigate this, we find that an entrepreneur can use a simple menu of rewards with a fixed number of units sold at a low price, and an unlimited number sold at a higher price; this segments contributors over time based on the information they observe upon arrival. We show that, despite its simplicity, such a menu performs well compared to a theoretically optimal menu consisting of an infinite number of different rewards and price levels under many conditions.     

Inventory transshipment game with limited supply: Trap or treat

Inventory transshipment is generally shown to be beneficial to retailers by matching their excess demand with surplus inventory. We investigate an inventory transshipment game with two newsvendor-type retailers under limited total supply and check whether the retailers are better off than the case without transshipment. We derive the ordering strategies for the retailers and show that unlike the unlimited supply case, a pure Nash equilibrium only exists under certain conditions. Furthermore, contrary to the conventional wisdom, we show that inventory transshipment may not always benefit both retailers. Although one of the retailers is guaranteed to be better off, the other could be worse off. The decision criteria are then provided for the retailers to determine if they will benefit from the exercise of inventory transshipment. Numerical study indicates that the carefully chosen transshipment prices play an important role in keeping inventory transshipment beneficial to both retailers. Subsequently, a coordinating mechanism is designed for the retailers to negotiate transshipment prices that maximize the total profit of the two retailers while keeping each of them in a beneficial position.     

【专题】复杂陆战场环境下的智能感知理论现状与发展

近年来,由于基于深度学习方法的智能检测算法不断演进,其网络结构不断进化,实用化程度不断提高,因此,将其应用于复杂战场环境下,形成实用化智能感知能力的可行性不断提高。然而算法的可靠性、可解释性问题目前仍未完全解决。本文认为,在未来的地面无人平台系统框架内,使用基于深度学习的目标检测识别方法,融合多种传感器感知信号,探索如何可靠地收集无人平台附近敌我车辆、人员、相关物体状况以及视距内的地理与气象环境信息,能够实现多元智能感知过程,构建智能复杂体系,为无人平台实现复杂战场环境感知理解,自主环境判定、自主行走、自主危险判定甚至威胁自动处置提供技术储备。同时,这也将是军队下一步智能感知理论方向的主要任务。     

Cell-type continuous electromagnetic radiation system generating millimeter waves for active denial system applications

The cell-type continuous electromagnetic radiation system is a demonstration device capable of generating high-power millimeter electromagnetic waves of a specific wavelength and observing their effects on living organisms. It irradiates a biological sample placed in a 30 × 30 × 50 cm³ cell with electromagnetic waves in the 3.15-mm-wavelength region (with an output of ≥1 W) and analyzes the temperature change of the sample. A vacuum electronic device-based coupled-cavity backward-wave oscillator converts the electron energy of the electron beam into radiofrequency (RF) energy and radiates it to the target through an antenna, increasing the temperature through the absorption of RF energy in the skin. The system causes pain and ultimately reduces combat power. A cell-type continuous electromagnetic radiation system consisting of four parts—an electromagnetic-wave generator, a high-voltage power supply, a test cell, and a system controller—generates an RF signal of ≥1 W in a continuous waveform at a 95-GHz center frequency, as well as a chemical solution with a dielectric constant similar to that of the skin of a living organism. An increase of 5 °C lasting approximately 10 s was confirmed through an experiment.     

Investigation on energy output structure of explosives near-ground explosion

In order to give the energy output structure of typical explosives near-ground explosion in real ground conditions, the free-field shockwave, ground reflection shockwave and Mach wave overpressure time history of composition B explosive, RDX explosive and aluminized explosive were measured by air pressure sensors and ground pressure sensors. The shape of the free-field shock wave, ground reflection shock wave, and Mach wave and explosion flame were captured by high-speed camera. The experimental results show that, at the same horizontal distance from the initiation point, the peak overpressure of explosive shock wave of composition B explosive, both in the air and on the ground, is less than that of RDX and aluminized explosives. At a distance of 3.0 m from the initiation point, the peak overpressure of aluminized explosives is slightly less than that of RDX explosives. Owing to the exothermic effect of aluminum powder, the pressure drop of aluminized explosives is slower than that of RDX explosives. At 5.0 m from the initiation point, the peak overpressure of aluminized explosives is larger than that of RDX explosives. At the same position from the initiation point, among the three kinds of explosives, the impulse of aluminized explosives is the maximum and the impulse of composition B explosives is the minimum. With the increase of the horizontal distance from the initiation point, the height of Mach triple-points (Mach steam) of the three explosives increases gradually. At the same horizontal distance from the initiation point, there is poorly difference in the height of Mach triple-points between aluminized explosive and RDX explosive, and the height of Mach triple-points of composition B explosive is much smaller than that of other two explosives. The maximum diameter and duration of the fireball formed by aluminized explosives are the largest, followed by composition B explosive, and the maximum diameter and duration of the fireball formed by RDX explosive are the smallest.     

Experimental study on explosion dispersion process of a multi-layer composite charge under different initiation modes

The influence of initiation modes on the explosive dispersion process of the multi-layer composite charge (MCC) was studied. Overpressure sensors and high-speed photography system were used to investigate the energy release process of an MCC with a specific structure. The shock wave pressure and explosive dispersion characteristics of the MCC under different initiation modes were compared. The forming and expanding process of the shock wave of the composite charge under different initiation modes was determined. The separation position of the shock wave and fireball interface was determined. The calculation formulas of the shock radius and overpressure of the composite charge are presented. The radius of the shock wave of the composite charge was significantly affected by the initiation mode. Moreover, the development process of the composite explosive fireball under different initiation modes was analyzed, the variation rules of the composite charge dispersion radius and fireball dispersion velocity with time were obtained under the different initiation modes, the explosion energy release rate of composite charge under simultaneous initiation modes was the highest, and the peak overpressure under the simultaneous initiation mode was 1.61 times that of central single-point initiation.     

基于知识图谱和二级传播理论的网络舆情事件传播分析

在目前的网络舆情事件传播分析中,尽管生命周期模型能够较好地描述舆情事件的发展规律,但却忽略了部分时期之间存在的共性特征,无法充分体现意见领袖对网络舆情事件传播过程的影响.本文提出了一种基于知识图谱和二级传播理论的网络舆情事件传播分析方法,首先,构建网络舆情事件知识图谱;然后,基于知识图谱计算用户影响力挖掘意见领袖;最后...