Dynamics of plasma bullets by nanosecond pulsed micro-hollow cathode discharge within air

In this paper,the air plasma jet produced by micro-hollow cathode discharge(MHCD)is investigated.The discharge is powered by a positive nanosecond pulse high voltage supply.The waveforms of the discharge,the images of the jet,the evolution of the plasma bullet and the reactive species are obtained to analyze the characteristics of the MHCD plasma jet.It is found that the length of the plasma jet is almost proportional to the air flow rate of 2–6 slm.Two plasma bullets appear one after another during a single period of the voltage waveform,and both of the two plasma bullets are formed during the positive pulse voltage off.The propagation velocity of the two plasma bullets is on the order of several hundred m/s,which is approximate to that of the air flow.These results indicate that the gas flow has an important influence on the formation of this MHCD plasma jet.

Interactions between optical bullets with different velocities in the three-dimensional cubic-quintic complex Ginzburg-Landau equation

By using the three-dimensional complex Ginzburg--Landau equation with cubic--quintic nonlinearity, this paper numerically investigates the interactions between optical bullets with different velocities in a dissipative system. The results reveal an abundance of interesting behaviours relating to the velocities of bullets： merging of the optical bullets into a single one at small velocities; periodic collisions at large velocities and disappearance of two bullets after several collisions in an intermediate region of velocity. Finally, it also reports that an extra bullet derives from the collision of optical bullets when optical bullets are at small velocities but with high energies.

A shield of defense:Developing ballistic composite panels with effective electromagnetic interference shielding absorption

The primary goal of this study is to develop cost-effective shield materials that offer effective protection against high-velocity ballistic impact and electromagnetic interference(EMI)shielding capabilities through absorption.Six fiber-reinforced epoxy composite panels,each with a different fabric material and stacking sequence,have been fabricated using a hand-layup vacuum bagging process.Two panels made of Kevlar and glass fibers,referred to as(K-NIJ)and(G-NIJ),have been tested according to the National Institute of Justice ballistic resistance protective materials test NIJ 0108.01 Standard-Level IIIA(9 mm×19 mm FMJ 124 g)test.Three panels,namely,a hybrid of Kevlar and glass(H-S),glass with ceramic particles(C-S),and glass with recycled rubber(R-S)have been impacted by the bullet at the center,while the fourth panel made of glass fiber(G-S)has been impacted at the side.EMI shielding properties have been measured in the X-band frequency range via the reflection-transmission method.Results indicate that four panels(K-NIJ,G-NIJ,H-S,and G-S)are capable of withstanding high-velocity impact by stopping the bullet from penetrating through the panels while maintaining their structural integrity.However,under such conditions,these panels may experience localized delamination with variable severity.The EMI measurements reveal that the highest absorptivity observed is 88% for the KNIJ panel at 10.8 GHz,while all panels maintain an average absorptivity above 65%.All panels act as a lossy medium with a peak absorptivity at different frequencies,with K-NIJ and H-S panels demonstrating the highest absorptivity.In summary,the study results in the development of a novel,costeffective,multifunctional glass fiber epoxy composite that combines ballistic and electromagnetic interference shielding properties.The material has been developed using a simple manufacturing method and exhibits remarkable ballistic protection that outperforms Kevlar in terms of shielding efficiency;no bullet penetration or back face signature is observed,and it also demonstrates high EMI shielding absorption.Overall,the materials developed show great promise for various applications,including the military and defense.

Controlling Airy-Bessel Light Bullets in an Optically Induced Potential

We investigate numerically the curious evolution of self-decelerating Airy-Bessel light bullets carrying different topological charges(TC), launched in the three-dimensional(3 D) Schrodinger equation with an induced parabolic potential. We present their spatiotemporal profile during propagation. In our paper, the number of TC, the modulation depth, and the induced potential are considered simultaneously. The propagation properties of light bullets result from a combination of these effects. Our scheme is distinctly different from the linear light bullets in free space, in which the localized wave packets propagate in a self-consistent trapping potential.

基于OSG和Bullet的船舶碰撞响应三维仿真

针对目前在航海模拟器中缺少对船舶碰撞响应的三维仿真,提出在航海模拟器中基于开源场景图形(Open Scene Graph,OSG)渲染引擎开发的三维视景中加入Bullet物理引擎的技术方案.根据刚体动力学、接触与碰撞动力学和能量守恒定律,基于Bullet刚体碰撞响应模型,建立船舶三维碰撞动力学模型;运用Projected Gauss-Seidel迭代算法,得到碰撞后船舶实时的六自由度位置姿态参数;根据碰撞检测阶段获取的碰撞点位置参数,实时绘制划痕并添加爆炸特效.该方案已成功应用于航海模拟器视景系统中,渲染效果良好.

基于Bullet物理引擎的机器人仿真实验平台设计

为适应新时代工业机器人实验教学的蓬勃发展,设计了一种基于Bullet物理引擎的机器人仿真实验平台。该平台使用Bullet作为仿真引擎,具备运动学解算、碰撞检测与轨迹可视化的功能,使用Lua脚本作为主逻辑控制语言,调用仿真引擎功能函数。使用基于数据流的节点图作为主实验交互平台,将计算模块和通信模块封装为功能节点,通过图形连接定义运算逻辑。应用实例表明,该平台功能完善,可扩展性强,兼具脚本语言的灵活性与图形化语言的便捷性,适用于机器人的多种实验场景。

影视后期制作中调色技术的应用与实践

本文主要对影视后期制作中的数字调色技术进行了介绍。对数字调色的工具——调色插件Color Finesse、magic bullet、Mocha及蒙板的基本技术点进行了详细的阐述。

碰撞检测技术在颗粒混合中的应用

采用图形引擎OSG和物理引擎Bullet,设计了片理颗粒混合碰撞仿真系统。在该系统实现过程中,首先对AABB、OBB、包围球及K-DOP算法进行对比研究,然后选择较为合适的AABB包围算法进行应用。该系统通过解决片理颗粒的控制、碰撞检测、OSG图形引擎与Bullet物理引擎结合以及场景渲染优化等关键技术问题,最后实现仿真模拟程序。

创新机构拼装与运动学仿真虚拟实验平台研究

通过分析真实实验流程,基于OSG(OpenSceneGraph)图形渲染引擎及Bullet物理引擎,提出根据机构设计方案,在虚拟环境中进行机构拼装,并对完成拼装的机构进行运动学仿真的实现方法,包括虚拟构件的信息建模与管理、装配约束特征识别、约束解算及机构运动学自动建模与运动解算等。基于这些方法,开发了机构拼装与运动仿真虚拟实验平台,以曲柄摇杆与摇杆滑块机构拼装实验对实现方法进行了验证。

Mechanisms of Streamer Propagation Affected by Driven Voltage Polarity in a Cold Atmospheric Pressure Plasma Jet

A two-dimensional self-consistent fluid model is used to investigate the effects of DC-voltage polarity in plasma initiation and propagation of helium plasma jet.The simulation results indicate that the difference in initial breakdown for the positive jet and negative jet leads to a difference in the electron density of about 4 orders of magnitude,even with the same initial electric field,which also influences the subsequent propagation.In the propagation process of negative jets,the ionization process exists in a longer gas channel behind the streamer head.In addition,the drift process to the infinite grounded electrode driven by the electric field results in higher energy consumption in the ionization process.However,in the positive jet,the ionization process mainly exists in the streamer head.Therefore,the differences in the initial breakdown and propagation process make the electric field intensity and the ionization weaker in the streamer head of the negative jet,which explains the weaker and shorter appearance of the negative jet compared to the positive jet.Our model can adequately reproduce the experimental results,viz.a bullet-like propagation in the positive jet and a continuous plasma plume in the negative jet.Furthermore,it also indicates that the streamer velocity shows the same variations as the electron drift velocity for both positive and negative jets.

Vaccines and Antibodies for Therapeutic Use in Cancers

This review describes briefly the beneficial use of two vaccines developed by us for treatment of cancers. The vaccine against Luteinizing Hormone Releasing Hormone (LHRH) is effective in carcinoma of prostate as well as in breast cancers dependent on androgens and estrogens respectively. LHRH being identical in both males and females, the same vaccine is usable in both Prostate and Breast steroid hormones-dependent-cancers. Monoclonal antibodies are finding therapeutic utility in several cancers, and many have received Drugs Regulatory approval. The monoclonals developed by us against hCG and against epitopes present on androgen-independent castration resistant prostate cancers are briefly recapitulated. Anti-hCG antibodies kill several cancers expressing hCG. An example is given of A549 lung carcinoma. MoAb730 and MoAb7B2G10 kill DU-145 and PC-3 androgen-independent castration resistant prostate cancer cells. Some cancers such as MOLT-4, a T-lymphoblastic leukemia, though expressing hCG are not killed by PiPP, the high affinity anti-hCG antibody. Linking the antibody to curcumin however works like a “Magic Bullet”. All MOLT-4 cells are killed by this conjugate, the antibody homes selectively to cancer cells expressing hCG to deliver curcumin which exercises the killing effect. A recombinant vaccine, hCGβ-LTB (human chorionic gonadotropin subunit β linked to B subunit of heat-labile enterotoxin of E. coli) has been made, which induces high titre bioeffective antibodies not only in BalbC, but also in other genetic strains of mice. The vaccine employs autoclaved Mycobacterium indicus pranii (MiP) as adjuvant. MiP invigorates both humoral and cell mediated immune responses against Human chorionic gonadotropin (hCG). Besides being a potent adjuvant, MiP used alone heals anogenital warts in humans and has the property of preventing and curing SP2/O Myelomas in mice.

Control of exterior ballistic properties of spin-stabilized bullet by optimizing internal mass distribution

This paper introduces a novel approach for controlling the exterior ballistic properties of spin-stabilized bullets by optimizing their internal mass distributions. Specifically, the properties of interest are the bullets’ stability characteristics that are examined through dynamic and gyroscopic stability parameters.New analytical expressions for aerodynamic quantities are also derived to address the compressibility of air. These expressions are utilized in a bullet model that enables efficient computation of the stability parameters for a given mass distribution. The bullet model is used in the formulation of nonlinear optimization problems that provide optimal mass distributions with respect to given goals, i.e., desired stability characteristics. The bullet types investigated in this paper are a long range bullet and a limited range training bullet. In the optimization of the mass distribution of the long range bullet, the goal is that the bullet stays stable for as long as possible. The mass distribution of the training bullet is optimized such that the bullet is stable at launch but becomes unstable shortly afterwards. The global optimal solutions obtained with the new approach fulfill the desired stability characteristics better than currently used uniformly filled bullets. Overall, the optimization approach reveals a new goal focused philosophy for bullet design compared to current trial and error design practices.

Experimental study of bullet-proofing capabilities of Kevlar, of different weights and number of layers, with 9mm projectiles

Kevlar is the most commonly used material as armour for protection against bullets used in hand guns because of its impact resistance, high strength and low weight. These properties make Kevlar an ideal material to be used in bullet-proof vests as compared to other materials. In the present study, different numbers of layers of Kevlar with different weights are tested to determine the weights and the number of layers needed to design a safe bullet-proof vest. For this purpose, several ballistic tests were performed on combinations of ballistic gel and Kevlar layers of different weights. Ballistic impacts are generated by 9 mm Parabellum ammunition. The objective is to assess the characteristics of high-speed ballistic penetration into a combination of a gel and Kevlar and determine the number of layers needed to safely stop the 9 mm bullet and thereby contribute to the design of safe bullet-proof vests. The tests provide information on the distances the bullets can travel in a gel/Kevlar medium before they are stopped and to identify the resistance capabilities of Kevlar of different grams per square meter(GSM). The tests were conducted with the use of a chronograph in a controlled test environment. Specifically, results identify the number of layers of Kevlar required to stop a 9 mm Parabellum projectile, and the effectiveness of using different number of layers of GSM Kevlar material.

An experiment evaluating how the tiny mass eccentricities in spinstabilized projectiles affect the position of impact points

This study investigates and quantifies some possible sources affecting the position of impact points of small caliber spin-stabilized projectiles(such as 12.7 mm bullets).A comparative experiment utilizing the control variable method was designed to figure out the influence of tiny eccentric centroids on the projectiles.The study critically analyzes data obtained from characteristic parameter measurements and precision trials.It also combines Sobol’s algorithm with an artificial intelligence algorithmdAdaptive Neuro-Fuzzy Inference Systems(ANFIS)ein order to conduct global sensitivity analysis and determine which parameters were most influential.The results indicate that the impact points of projectiles with an entry angle of 0°deflected to the left to that of projectiles with an entry angle of 90°.The difference of the mean coordinates of impact points was about 12.61 cm at a target range of 200 m.Variance analysis indicated that the entry angleei.e.the initial position of mass eccentricityehad a notable influence.After global sensitivity analysis,the significance of the effect of mass eccentricity was confirmed again and the most influential factors were determined to be the axial moment and transverse moment of inertia(Izz Iyy),the mass of a projectile(m),the distance between nose and center of mass along the symmetry axis for a projectile(Lm),and the eccentric distance of the centroid(Lr).The results imply that the control scheme by means of modifying mass center(moving mass or mass eccentricity)is promising for designing small-caliber spin-stabilized projectiles.

Development of a portable cold air plasma jet device and observation of its photo ionization process

Photo ionization plays a critical role in the formation and propagation of atmospheric pressure plasma jet plumes.But in experiments,it is very difficult to observe the photo ionization due to its relative lower density of photo electrons.In the present study,we develop a portable cold air plasma jet device and observe the ionization wave in adc spark air plasma jet.The discharge images acquired by an ICCD camera show that the ionization wave front performs as a quickly moving bright ball.Breakdown could take place at another side of the quartz plate or pork tissue layer(6 mm thick),which suggests that the ionization should be attributed to photo ionization.The laser schlieren images indicate there is propagation of a shock wave along with the plasma bullet.Based on the photo ionization theory and the photo-electric measurement,the direct photo ionization and multistage photo ionization are the main factors in charge of generating the cold air plasma jet.In addition,the plasma jet outside of the cathode nozzle is colder than 320 K and can be touched safely by a human.In view of the plasma jet including a large amount of active particles,such as NO,O,OH,emitted photons,etc,the proposed portable cold air plasma jet device could be qualified for plasma bio-medicine applications.

Calculation and Test of Hitting Force of Firing Bullet on the Bulletproof Helmet

In this paper the hit force of firing bullet on bulletproof helmet has been computed and the test device has been described. The device is divided into two parts: 1) The bullet, helmet and mould are in one system, using moment theorem to calculate the hit force; 2) The mould, sensor and support pole are in one system, using the method in reference [1] that measures the dynamic strain and displacement of simulate target of bulletproof clothes. We compute the transfigure energy and momentum energy when hitting the mould, the work done by the sensor and the expend energy of support pole. We get the hit force of helmet using energy balance principle. The result is according with the test and has been used to design the GGK93T bulletproof helmet and other serial products.

一种三维数字地球场景下的重力仿真方法

本文提出一种在数字地球大场景中加入物理引擎实现重力仿真的方法。为了解决以图形渲染为核心的数字地球显示模块效率问题,本方法使用开放图形渲染引擎OGRE构造数字地球显示,结合物理引擎Bullet,实现含物理重力特性的三维数字地球场景。最后,设计了一组自由落体实验,验证本重力仿真方法的可行性和准确性。实验结果证明,本文重力仿真方法有效且准确性高,能为数字地球大场景引入重力仿真提供借鉴和参考。

ANALYSIS OF AERODYNAMIC CHARACTERISTIC ON GLIDE BULLET TO INCREASE RANGE

This paper mainly calculates, analyzes and compares the aerodynamic characteristics of two kinds of bullets, one has wing, and the other has no wing. The calculated results indicate that the lift force of the glide bullet with wing is much bigger than that has no wing, and it reached the aim to increase range.

Effect of rifle bullet parameters on the penetration into ballistic gelatin

To understand the effects of the rifle bullet parameters on the bullet-gelatin interaction quantitatively, a finite element model of bullet penetrating gelatin was set up and computational re- suits are compared with experimental ones. The penetration of the rifle bullet into the gelatin was simulated by the nonlinear finite element method. The quantitative analysis of the changes in the ge- latin interaction with the rifle bullet were conducted by changing the bullet parameters, such as at- tack angle on gelatin, initial velocity, warhead＇ s tip and location of mass center of bullet. Results demonstrate that with the increase of the attack angle, instable moment of the bullet moves forward, the length of narrow wound channel shortens, and when penetration is completed diameters of tem- porary cavities increase, the gelatin energy and energy transmission ratio increases; With the in- crease of the impact velocity, instable moment of the bullet moves forward, the maximum forces acting on the gelatin and the gelatin energy increase remarkably ; the length of narrow wound channel shortens, diameters of temporary cavities increase when penetration is completed, the gelatin energy and energy transmission ratio increase; The warhead＇ s tip and location of mass center have a influ- ence on the instable moment of the bullet and length of the narrow wound channel. The instable mo- ment delays and narrow wound channel increases when the warhead＇s tip flattens. The instable mo- ment moves forward a little and the narrow wound channel shortens a little when location of mass center moves back.