检索结果-南通市图书馆

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

引用

Defence Technology（防务技术） 2024年第5期35卷 123-136页

作者： Nisrin Rizek Abdelal Mechanical Engineering Department Jordan University of Science and TechnologyIrbid 22110Jordan

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,

关键词： Ballistic FRP composite EMI shielding Absorptivity CT-Scan NIJ test bullet Defense

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

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

引用

Defence Technology（防务技术） 2019年第1期15卷 38-50页

作者： Janne Lahti Timo Sailaranta Mikko Harju Kai Virtanen Systems Analysis Laboratory Department of Mathematics and Systems AnalysisAalto University Aero RD Ltd Systems Analysis Laboratory Department of Mathematics and Systems AnalysisAalto Universit Department of Military Technology National Defence University of Finland

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.

关键词： Aerodynamics bullet Exterior ballistics Mass properties Optimization Stability

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

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

引用

Defence Technology（防务技术） 2019年第2期15卷 186-192页

作者： Riaan Stopforth Sarp Adali Stopforth Mechatronics Robotics and Research Lab Discipline of Mechanical Engineering University of Kwazulu-Natal Centre for Composite Materials and Structures Discipline of Mechanical EngineeringUniversity of KwaZulu-Natal

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.

关键词： Kevlar 9mm Parabellum bullet Ballistic impact Ballistic gel Material testing

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of rifle bullet parameters on the penetration into ballistic gelatin

引用

Journal of Beijing Institute of Technology 2015年第4期24卷 487-493页

作者：刘苏苏徐诚陈爱军李宏魁 School of Mechanical Engineering Nanjing University of Science and Technology School of Science Nanjing University of Science and Technology Baicheng Ordnance Test Center

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.

关键词： bullet gelatin penetration temporary cavity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

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

引用

Plasma Science and Technology 2020年第8期22卷 99-108页

作者：陈兆权吴金芳张煌张明张三阳冯德仁 Anhui Key Laboratory of Electrical Drive and Power Electronics Anhui University of TechnologyMaanshan 243032People's Republic of China

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.

关键词： photo ionization air plasma jet plasma bullet ionization wave

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

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

引用

Defence Technology（防务技术） 2021年第3期17卷 948-960页

作者： Chuan-lin Chen Hui Xu Chen-lei Huang Zhong-xin Li Zhi-lin Wu School of Mechanical Engineering Nanjing University of Science and TechnologyNanjingJiangsu210094China

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.***.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.

关键词： Tiny mass eccentricity Small-caliber projectile bullet Artificial intelligence algorithm Global sensitivity analyses Precision trials ANFIS Sobol’s algorithm

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

ANALYSIS OF AERODYNAMIC CHARACTERISTIC ON GLIDE bullet TO INCREASE RANGE

引用

Transactions of Nanjing University of Aeronautics and Astronautics 2001年第Z1期18卷 39-42页

作者： Chen Shaosong Wu Pin Zhao Runxiang(College of Power Engineering,Nanjing University of Science and Technology Nanjing 210094,P.R.China) College of Power Engineering Nanjing University of Science and Technology Nanjing 210094P. R. China

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 bu... 详细信息

关键词： glide bullet wing aerodynamic characteristic

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A newly developed open-end intracranial hematoma drainage tube

引用

Translational Neuroscience and Clinics 2016年第2期2卷 150-152页

作者： Chao He Nongnaphat Wanussakul Dong Yang Tianya Wu Ming Zhao The People’s Hospital of Zhuji The Second Affiliated Hospital of Zhejiang

Objective: To design a new open-end intracranial hematoma drainage tube for clinical application. Methods: The newly developed device consists of two parts: the plunger and barrel.On one side, the barrel is bullet shaped with an opening tip. The plunger is located in the middle cavity of the tube barrel and extended out at the open-end. It was designed for strengthening the tube barrel and for convenience in performing the drainage procedure. It can be used by inserting the drainage tube into the lesion and pulling out the plunger, whereby blood will forcefully rise up inside the barrel, providing a satisfactory outcome. It is made for effusion drainage purposes. During the procedure, the drainage tip is placed at the deepest part of the intracranial hematoma to completely drain the blood. Moreover, the plunger fits tightly in the tube, preventing leakage during the operation. With the use of the device, brain can be separated. In addition, the device can help reduce the risk of cerebral damage because of the small operating area. The barrel sidewall has matching opening holes bilaterally and equally for exchanging substances between the inner and outer parts.The overlapping ratio in each horizontal pair is around 1/3–1/2. Each pair on the opposite side will form a different pressure. Thus, the opening holes will not easily get blocked with blood clot. Results: Blood and accumulated liquid from the deepest part of the intracranial hematoma can be directly drawn through the drainage tube without damaging a large area. The tube does not get blocked easily and allows for complete removal of the hematoma. Conclusions: The device is asuitable instrument for clinical application.

关键词： open-end drainage tube bullet shape barrel plunger stereotaxic drainage matching holes on each side

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Atypical Gunshot Injury to the Ear: A Case Report

引用

International Journal of Otolaryngology and Head & Neck Surgery 2015年第2期4卷 73-76页

作者： Sai Spoorthi Nayak Ehrlson De Sousa Saumyata Neeraj Department of ENT Goa Medical College Goa India

bullet injuries to head and neck are usually associated with high mortality and morbidity due to a number of vital structures lying in close proximity. We present a rare case of air-gun injury with an unusual entry wo... 详细信息

关键词： bullet Perforated Tympanic Membrane Metallic Foreign Body

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pressure Changes in Water and Gelatin Blocks due to Three Different Projectiles

引用

Military Medical Research 1986年第1期 27-30页

作者：刘荫秋郭瑞峰吴炳杰李曙光王大田 Chongqing. Research Institute of Surgery Third Military Medical College

The pressure changes produced by firing bullets of 7.62mm and 5.56mmand steel sphere of 1.03g through water and 20% gelatin blocks werestudied.The pressure was measured by a transducer of Model B-J 1000.It was demonstrated that there were three peaks produced when thetwo kinds of bullets were fired through a water tank.The interval betweentwo successive peaks was longer in the waves produced by the 7.62mmbullet than in those produced by the 5.56mm bullet.The peak value ofthe 5.56mm bullet was the largest,that of the 7.62mm bullet the second,and that of 1.03g steel sphere the lowest.The fore-mentioned differences among the pressures produced by differentprojectiles were dependent on their respective ballistic characteristics.Thepressure value detected and the patterns of the pressure changes were closelyrelated to the temporary cavity effect and the characteristics of tissue da-mage.

关键词： pressure changes in water and gelatin bullet steel sphere ballistics

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：