Molybdenum disulfide (MS2), tungsten disulfide (WS2), hexagonal boron nitride (HBN), and Lubalox are common bullet coatings that purportedly reduce friction between the bullet and rifle barrel. Three different bullets, one a solid copper design, and two jacketed lead bullet designs, were tested in the 5.56 mm NATO rifle cartridge. After coating, these bullets were test fired through a chronograph with powder charges ranging from 0.52 grams to 0.91 grams. The energies of these bullets along with a control group of uncoated bullets were plotted against the powder charges. The work of friction for each combination was then determined as the vertical intercept obtained by least squares regression to a line. The different coating and bullet combinations produced changes in friction ranging from reductions in friction of 15to increases in friction of 19. Given the time and expense of coating bullets, the reduction in friction is not cost effective for most applications.

关键词：钢铁；铜；记时器；钼化合物；小型武器弹药

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This article explains how Task Force Commando; 10th Mountain Division utilized both human factors and emerging technology to better utilize Unmanned Aircraft Systems throughout the Paktika Province on the 2013 deployment to Afghanistan s RC- East. Early in their deployment it was apparent to LTC Jason Bridges, Task Force Gladiator commander that communication between Route Clearance Platoons and UAS operators was insufficient. Despite having FM retrains capabilities on the aircraft which allows for extended FM communications, UAS operators and ground patrol leaders often could not communicate via FM due to atmospheric and mountainous terrain conditions.

关键词：通信网络;阿富汗；无人机；工作队；蒲福风级（蓝色因素跟踪器）

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This program was undertaken to develop a microalloy-modified grade of standard carburizing steel that can successfully exploit the high temperature carburizing capabilities of current commercial low pressure (i.e. 'vacuum') carburizing systems. Such steels can lower the amount of energy required for commercial carburizing operations by reducing the time required for deep-case carburizing operations. The specific technical objective of the work was to demonstrate a carburizing steel composition capable of maintaining a prior austenite grain size no larger than ASTM grain size number 5 after exposure to simulated carburizing conditions of 1050 C for 8 hr. Such thermal exposure should be adequate for producing carburized case depths up to about 2 mm. Such carburizing steels are expected to be attractive for use across a wide range of industries, including the petroleum, chemical, forest products, automotive, mining and industrial equipment industries. They have potential for reducing energy usage during low pressure carburizing by more than 25, as well as reducing cycle times and process costs substantially. They also have potential for reducing greenhouse gas emissions from existing low pressure carburizing furnaces by more than 25. High temperature carburizing can be done in most modern low pressure carburizing systems with no additional capital investment. Accordingly, implementing this technology on carburizing furnaces will provide a return on investment significantly greater than 10. If disseminated throughout the domestic carburizing community, the technology has potential for saving on the order of 23 to 34 trillion BTU/year in industrial energy usage. Under the program, two compositions of microalloyed, coarsening-resistant low alloy carburizing steels were developed, produced and evaluated. After vacuum annealing at 1050oC for 8 hrs and high pressure gas quenching, both steels exhibited a prior austenite ASTM grain size number of 5.0 or finer. For comparison, a control alloy of similar composition but without the microalloy additions exhibited a duplex prior austenite grain size with grains ranging from ASTM grain size 3 down to ASTM grain size 1 after similar processing and thermal exposure. These results confirm the potential for using microalloy additions of Ti, B, Nb, Al, rare earths and/or N for austenite grain size control in Cr-Mo (i.e. 4000-series) low alloy carburizing steels. They also demonstrate that these microalloy additions will not compromise the processability of the steel; all three materials produced under the program could be hot worked readily using normal steel processing protocols. To fully realize the technical and commercial potential of these steels, there is a need to continue development work using larger-scale heats. These larger-scale heats are needed to provide adequate material for fatigue testing of quenched and tempered alloys, to conduct more complete investigations of potential alloy chemistries and to provide additional material for processing studies.

关键词：钢;渗碳;算法;合金

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On the basis of the theoretical study and application of ordinary steel-encased concrete composite beam,this paper will focus on a new high-strength steel-encased concrete composite beam,and mainly studies high-performance steel Q420 and Q460,as well as high-strength concrete C60 and C80.Besides,an experimental study of 5 simply-supported beams is made,and the load-deflection curves of new SCCB are analyzed.The calculation formula of load which changes with depth of section and bending strength of the cross section is also analyzed.It is suggested that the calculated results announced should be identical with the experimental results.

关键词：高强度钢-混凝土组合梁（SCCB下同）;高性能钢，高强度混凝土;抗弯承载力

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One serious problem reinforced concrete bridge decks face throughout the United States is the development of several cracks. Concrete bridge decks of all ages and sizes, some even constructed within the last several years, show different levels of cracking. Regardless of the type of superstructure, the number and length of spans, and the type of concrete used, cracks inevitably develop in every reinforced concrete bridge deck. There is a need to study the extent of cracking developed in concrete bridge decks so that the causes of cracking can be identified and counter measures established to minimize cracking in future bridge deck constructions. Cracks are critical on bridge decks because cracks provide access to harmful, corrosive chemicals that deteriorate the reinforcing steel, which is embedded within the concrete. Once chloride and other deteriorating agents penetrate concrete and make contact with the reinforcing steel, the deteriorating agents will corrode the steel, cause spalling, and eventually cause a loss of cross sectional area for the reinforcing steel. Such deterioration can affect the shear and moment capacity of reinforced concrete bridge decks. Also, the bridge deck cracks allow water and deicing salts to leak down through the bridge deck and damage the substructure and affect the aesthetics of the bridge.

关键词：桥面;钢筋混凝土;开裂;腐蚀

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In Cognitive Radio Network (CRN),where Primary User (PU) and multiple Secondary Users (SUs) wish to communicate with their corresponding receivers simultaneously over fading channels,spectrum utilization and efficient resource allocation are both significant points for CRN.Interference between PU and SUs should be eliminated in order to realize spectrum sharing.Multi-user resource allocation with the target of maximizing the spectral efficiency of SUs and satisfying the proportional rate constraint between SUs are proposed under the conditions of total SU interference constraint.An adaptive low-complexity suboptimal algorithm for subcarrier and power joint allocation is presented based on Rate Adaptive (RA) criterion,where adaptive subcarrier allocation is performed by assuming equal power distribution,while each subcarrier is assigned in accordance with subcarrier efficiency function.Moreover,linear water-filling algorithm for power allocation is applied within each subcarrier.Simulation results indicate that,with the proposed adaptive subcarrier allocation,spectral efficiency of multiple SUs is superior to traditional subcarrier power joint allocation algorithm.Low computational complexity and adaptive features make it available for implementation.

关键词：认知无线电网络;自适应子载波分配;衰落信道

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network—at an estimated cost of about $3 billion per year indefinitely—to improve communication and other capabilities and to provide needed information to soldiers and commanders on the battlefield. The Army has identified this network as its number one modernization priority. For nearly 20 years, the Army has had limited success in developing its information network of sensors, software, and radios to give soldiers and commanders exact information when they need it, in any environment, and thus improve situational awareness and decision making in combat. To achieve this goal, the Army is implementing a new agile process

关键词：通信网络；军队人员；信息系统；测试

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This thesis explores a novel network design concept to address the data and communications needs of the Department of Defense (DoD). Current and future military operations are increasingly reliant upon data connectivity to facilitate situational awareness and distribute vital information. Current infrastructures are insufficient to meet the growing demand, especially in the myriad austere environments where military forces operate. The DoD has become reliant upon increasingly vulnerable and expensive satellite communications to fill those gaps. The wireless data technologies utilized in the commercial sector to meet the data distribution requirements of business and commercial telecommunications providers can be leveraged and adapted to meet the connectivity requirements of the DoD. By pairing these technologies with developing HAPs and their capabilities the potential for a long-range wireless broadband solution emerges. This thesis evaluates broadband wireless data technologies in combination with High Altitude Platform (HAP) technologies. It proposes a network design concept to serve as a model for future research and the ultimate integration of HAPs into battlefield information architectures bringing the concepts of network centric warfare ever closer to reality.

关键词：无线计算机网络；宽带；通信和无线电系统；数据处理

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4Cr5MoSiV1 steel,a widely used for hot work mould,contains Cr,Mo,V alloying elements that easily form carbides.The Micro-area chemical composition,microstructure,impact toughness and thermal fatigue behavior of 4Cr5MoSiV1 and 4Cr5MoSiV1H steels were investigated,the latter was carried on high temperature homogenizing and solution based on the former.The results showed that bulk eutectic carbides and elements segregation contained in the 4Cr5MoSiV1 steel reduced the impact toughness.But the impact toughness of the core of the mould steel block and thermal fatigue property of 4Cr5MoSiV1H steel were improved because the elements segregation and eutectic carbides was eliminated through the high temperature homogenizing and solution.

关键词：钢；高温均匀化；元素偏析；力学性能

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The six important technical areas were selected by the workshop organizing committee, a group of experts from the auto and steel industries, and scientists from several National Laboratories. These selections were based on areas where there were known technical gaps, which if closed would have high impact on accelerating vehicle lightweighting with AHSS. The selected areas were: Steel Development, Fracture, Plasticity, Delayed Fracture/Hydrogen Embrittlement, Modulus Characterization and Joining. The main output of the workshop is contained within the breakout session reports, which summarize the technical requirements, engineering gaps and research needs. The breakout session reports are included below in the main workshop report.

关键词：钢铁；汽车；材料加工；车间；汽车燃料

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