Sintering Behaviour of Al_2O_3-SiC-C Ramming Mix

Silicon fines, boron acid solid powders and microfine SiO 2 as sintering agents were incorporated into Al 2O 3-SiC-C ramming mix in order to investigated their effects on the microstructure, mechanical properties and sintering behavior of the ramming mix. Results show that all the three agents could improved both densification and mehanical properties markedly, compared to that of non-agent specimens and the effect of the composite of boron acid solid powders and microfine SiO 2 is the best. The oxidation resistance increased with the addition of agents, which is supported by densification. Microstructures showed that agent powders could fill pores or produce liquid phases at high temperature, therefore, improve the sintering of the ramming mix.

Environmental-friendly Ramming Materials for Mud Package and Taphole of Large-scaled Blast Furnaces

The compositions, structures and properties of envi- ronmental-friendly ramming materials for mud package and taphole of large-scaled blast furnaces were studied. The results show that the formation of silica fibers makes structure of ramming materials dense. During the process of extruding mud and ramming materials, SiC is partly oxidized ; CaO , F% 03 and carbon penetrate towards the outer wall. The improvement of ramming materials can inhibit the penetration of molten slag, iron and carbon. The bulk density of environmental-friendly ramming ma- terials dried at 200 ℃ is 2.90 g · cm-3, the cold com- pressive strength of this kind of ramming materials dried at 200 ℃ is about 17. 0 MPa and fired at I 450 ℃ is about 39. 2 MPa.

Influence of Raw Material on the Properties of MgO-Al_2O_3-Cr_2O_3 Ramming Mixes

Mg0-Al2O3-Cr2O3 ramming mixes made of different raw materials have different mineral structure and different physical properties though with the identical particle size distribution, the same amount of binder and chemical composition . The residual carbon content of the fused magnesia-chrome material made in reducing atmosphere is very high, if this material is used in the MgO-Al203-Cr2O3 ramming mix , it would cause spalling of the furnace lining during drying-out.

Effect of Magnesia-Chrome Synthetic Materials on Magnesia-Alumina-Chrome Ramming Mixes

Magnesia-alumina-chrome ramming mixes with same chemical compositions were prepared by using different raw materials such as fused magnesia-chrome synthetic materials and sintered one, wasted bricks and magnesia-alumina spinels. Their physical properties were tested and microstructures were analyzed. The results show that the ramming mixes made of different raw materials bring about different microstructures and properties although the mixes have the same chemical composition, binder content and aggregate size composition.

Advanced Ramming Mix Based on Fused Zirconia Stabilized by Com-bined Additives of CaO and MgO for Lining of Carbon Black Production Reactor

Fused materials from ZrO2 stabilized by CaO or MgO, or the combined additive consisting of CaO and MgO are made. With using chemical, petrographic, X-ray phase and electron microscopic researches the main characteristics of these materials are determined. It is shown that, the materials of all compositions have low water absorption; they are characterized by equal struc-ture. The materials stabilized by the combined additive consisting of CaO and MgO are presented by generally the cubic phase and a small amount of tetragonal and monoclinic ZrO2 phases. Depending on CaO： MgO ratio in the materials the tetragonal ZrO2 phase settles down in a cubic matrix in the form of separate grains, and sites of net like structure in the form of a ＂woven＂ interlacing （2.9% of CaO and 2. 6% of MgO ）. An influence of the above mentioned fused stabilized ZrO2 materials and quantity of monoclinic zirconia, on the forming of zirconia mix on a phosphate bond and properties of＂ .fired samples is studied. The samples from mix based on ZrO2 stabilized by the combined additive consisting of 2.9% CaO and 2.6% MgO with 20% of monoclinic Zr02 are characterized by the highest properties： after .firing at 1 580 ~C open porosity of 14. 3% - 14. 8%, apparent density of 4. 67 -4. 69 g · cm^-5, cold crushing strength of 62 - 68 MPa, thermal shock resistance （ 1 300℃←→air） of 15 thermal cycles, linear growth of 0. 2%. The manufacturing technology of powders mix-ture for ramming mix based on the new fused material .from ZrO2 stabilized by the combined additive is developed and its production is mastered. From this mixture the large-size, shaped products on the phosphate bond are made at one carbon black production plant, which are installed in the combustion chamber of the carbon black production reactor.

Effect of Al Addition on Properties of Al_2O_3-SiC-C Dry Ramming Mixes for BF Trough

Aluminium powders were introduced to Al2O3-SiC-C dry ramming mixes in order to improve sintering properties and oxidation resistance according to their service conditions and installation methods. Properties such as bulk density, porosity, modulus of rupture, crushing strength and hot modulus of rupture as a function of aluminium addition were investigated in the present work. The microstructure and thermodynamics for the heat treated specimens were also analyzed. The results show that as aluminium addition increasing, the bulk density of the specimen treated at 220℃ tends to decrease and the apparent porosity increases, the strength of the specimens treated at 1100℃ and 1450℃ increases markedly, the bulk density tends to increase, apparent porosity and linear shrinkage decrease. The HMOR at 1400℃ is enhanced from 1.0 MPa to 3.5 MPa with 3% aluminium. Aluminium is served as sintering agent and anti-oxidant and it will react with CO and CO2 forming Al2O3 , which is helpful to enhance the strength, densify the structure and improve the overall properties.

Carbon Ramming Materials for Blast Furnace Construction

1 Scope This standard specifies the definition, classifica- tion, technical requirements, test methods, quality ap- praisal procedure, packing, marking, transportation, stroage and quality certificate of carbon ramming mate- rials for blast furnace construction. This standard is applicable to carbon ramming materials for construction in leveling layer of blast furnace bottom, ramming layer upper or lower the cen- tral line of water cooling pipes, joints between carbon bricks, or joints between carbon bricks and cooling equipment.

一种使用Flash阵列存储数据的方法研究

在航空航天领域,随着飞行器性能的提升,研制过程中试验所需的数据存储量和数据存储速度也在不断提高。该文基于高速大容量数据存储的目的,利用FPGA的强大数据处理能力,进行Flash存储阵列及流水线管理的设计,并针对Flash阵列坏块检测和突发坏块提出了对应处理方法。通过对不同组合方式的存储阵列速度及存储容量进行研究对比,得到了一种使用Flash阵列进行高速数据存储的设计方法。相较单片存储,设计的存储阵列数据存储容量和速度成倍增加,且存储阵列的有效块利用率在99%以上。

基于改进平方根无迹粒子滤波的RAM类目标跟踪

RAM类目标运动复杂,对跟踪系统提出了更高的要求。针对粒子滤波在解决RAM类目标跟踪过程中存在的粒子退化等问题,通过无迹变换计算得出后验概率密度函数充当粒子滤波的先验概率密度函数,提高后验概率密度函数拟合程度,最终提高粒子的有效性。同时,在无迹变换过程中采用qr分解取代部分Cholesky分解,使输出信号方差矩阵保持非负性。最后,针对一段RAM类目标轨迹建立动力学模型,通过Matlab进行仿真,验证了该算法的有效性。

Enhanced structural damage behavior of liquid-filled tank by reactive material projectile impact

A series of ballistic experiments were performed to investigate the damage behavior of high velocity reactive material projectiles(RMPs) impacting liquid-filled tanks,and the corresponding hydrodynamic ram(HRAM) was studied in detail.PTFE/Al/W RMPs with steel-like and aluminum-like densities were prepared by a pressing/sintering process.The projectiles impacted a liquid-filled steel tank with front aluminum panel at approximately 1250 m/s.The corresponding cavity evolution characteristics and HRAM pressure were recorded by high-speed camera and pressure acquisition system,and further compared to those of steel and aluminum projectiles.Significantly different from the conical cavity formed by the inert metal projectile,the cavity formed by the RMP appeared as an ellipsoid with a conical front.The RMPs were demonstrated to enhance the radial growth velocity of cavity,the global HRAM pressure amplitude and the front panel damage,indicating the enhanced HRAM and structural damage behavior.Furthermore,combining the impact-induced fragmentation and deflagration characteristics,the cavity evolution of RMPs under the combined effect of kinetic energy impact and chemical energy release was analyzed.The mechanism of enhanced HRAM pressure induced by the RMPs was further revealed based on the theoretical model of the initial impact wave and the impulse analysis.Finally,the linear correlation between the deformation-thickness ratio and the non-dimensional impulse for the front panel was obtained and analyzed.It was determined that the enhanced near-field impulse induced by the RMPs was the dominant reason for the enhanced structural damage behavior.

浸没燃烧式气化器SCV的RAM分析及可用度优化

浸没燃烧式气化器(SCV)是液化天然气LNG应急调峰站的关键核心系统,系统中出现设备故障会导致天然气供应中断,将造成显著社会影响与生产损失。为了评估SCV系统的生产性能及提高运行稳定性,提出并建立SCV-RAM分析模型,应用蒙特卡洛模拟仿真定量辨识SCV的瓶颈单元设备并针对性设计改进方案。结果表明,SCV系统易发生故障的单元按贡献度依次分别是:助燃空气单元、循环冷却水单元,其中导致系统不可用度增大的具体关键设备为水泵、电机以及鼓风机。据此对关键设备的预防性维修间隔进行优化,SCV系统的全寿命周期统计可用度从90.17%提高到94.93%,总停机时间减少了3478h。分析结果有助于优化SCV系统的维修资源分配,为实现SCV系统长周期稳定运行提供技术支持。

多腔梯度序贯充压联合Caprini RAM量表指导下的康复方案对肺癌患者术后深静脉血栓的影响

目的探讨多腔梯度序贯充压联合Caprini RAM量表指导下的康复方案对肺癌患者术后深静脉血栓的影响。方法选择2020年1月-2023年1月我院收治的肺癌患者150例,将2020年1月-2021年12月收治的75例患者列为常规组,2022年1月-2023年1月收治的75例患者列为观察组。常规组实施多腔梯度序贯充压治疗与传统护理,观察组实施多腔梯度序贯充压联合Caprini RAM量表指导下的康复方案。观察两组DVT预防知识、结局相关指标和护理满意度。结果观察组干预后DVT预防知识得分明显高于常规组,患者下肢DVT发生率、D-二聚体、下肢周径差均明显低于常规组,住院时间短于常规组(P<0.05),观察组护理满意度明显高于常规组(P<0.05)。结论多腔梯度序贯充压联合Caprini RAM量表指导下的康复方案可提高肺癌患者术后DVT预防知识水平,促进康复进程,提升患者满意度。

新型列控系统ATP车载设备开发过程安全控制措施研究

作为下一代列控系统的重要组成部分,新型列控ATP车载设备的设计开发需严格按照行业技术要求执行安全控制措施,以确保设备满足安全需求。从RAMS分析、系统测试、验证确认3个方面对设备开发过程中的安全控制措施展开研究:根据新型列控ATP车载设备的功能分析,采用Relex Studio建立可靠性框图及故障树模型,计算设备的RAMS等各指标符合技术条件要求;针对系统测试需求,设计测试流程,搭建仿真测试环境进行系统测试;通过具体验证活动与多种确认方法,验证新型列控ATP车载设备能够在目标环境中有效运行。新型列控ATP车载设备所采取的安全控制措施可提高其可靠性与安全性,为其他安全相关的铁路信号设备的设计开发提供参考。

浅析基于RAMS的轨道交通车辆状态评估方法

随着轨道交通的快速发展,对其关键部件可靠性、可用性、安全性以及维修性的评估方法提出了更高的要求。因此提出了基于RAMS的轨道交通车辆状态评估方法,应用RAMS对关键部件进行状态评估,其中利用安全性确定部件维修方式,可靠性确定部件维修时间间隔,可用性判断部件维修状态。

基于双口RAM接收并处理1553B总线数据的方法研究

为了保证主机板和1553B板通过双口RAM(Random Access Memory,随机存取存储器)进行1553B总线通信时的正确性和可靠性,提出了一种利用双口RAM接收并处理1553B总线数据的方法,用于实现1553B的BC(Bus Controller,总线控制器)功能。该方法对双口RAM中的地址按照子地址号进行地址分配,通过建立相同子地址序号的数据链表和建立环形缓冲区,完美解决了发送BC→RT(Remote Terminal,远程终端)报文时相同子地址数据覆盖和主机端发送的子地址序号顺序与1553B板端发送的子地址序号顺序不一致等问题。

基于FPGA的异步双端口RAM芯片原型验证研究

为保证芯片功能符合预期,提高流片成功率,异步双端口RAM芯片设计在流片前进行充分的功能验证,其中FPGA原型验证能够重现芯片的实际工作环境,以此验证芯片设计的有效性。基于FPGA的异步双端口RAM芯片原型验证根据芯片定义,选择使用Intel公司的10M40DCF256FPGA为核心硬件搭建FPGA原型验证平台,在平台上通过完成从ASIC到FPGA的代码移植实现芯片原型,然后根据设计需求编写测试程序实现对该芯片的FPGA原型验证。测试结果均符合预期,表明异步双端口RAM芯片的功能符合设计需求,避免项目时间和资金成本的额外增加。

Simulation on Reliability Enhancement Testing Technology of Ramming System

Ramming system is the key device to guarantee the firing speed of self-propelled gun. Based on traditional reliability enhancement testing method, a new kind of reliability enhancement testing simulation method of ramming system is put forward firstly. In CAD software Pro/E and dynamic simulation software ADAMS, the virtual prototype of ramming system is established. In EASY5 software, the corresponding hydraulic system and control system models are built. The reliability enhancement testing virtual environment of ramming system is developed using the mechanical-electrical-hydraulic co-simulation technology. Based on the load spectra provided by virtual prototype, and the stress distribution provided by finite element analysis and material's S-N curve(S is fatigue strength, N is fatigue life), a model of fatigue enhancement coefficient is established through the failure mechanism analysis. The simulation processes and simulation results show the feasibility of reliability enhancement testing based on virtual prototype, and provide sufficient theory reference for structure improvement and optimization of ramming system.

轨道交通装备制造企业的RAMS体系分析

本文以轨道交通装备制造企业RAMS体系为研究对象,论述了建立RAMS体系的必要性,分析了轨道交通装备制造企业RAMS体系管理组织、体系文件和审核等要素,对轨道交通装备制造企业RAMS体系落实情况进行了简要分析,为轨道交通装备制造企业完善RAMS体系、建立切实有效的执行方法提供了参考。

一种基于FPGA的ECC点乘优化设计

现场可编程门阵列(field programmable gate array,FPGA)具有丰富的计算、存储等资源,广泛应用于密码算法、实时通信等高并行、高数据吞吐量、计算复杂的领域。现有的基于FPGA实现ECC点乘的方案,存在计算架构设计并行程度低,计算所需的逻辑资源过大的问题。针对以上问题,提出了一种基于FPGA实现ECC点乘的优化设计。通过采用RAM寻址方式设计出计算架构,并构造了一个流水线状态机,利用FPGA并行计算的优势,多次并行使能调用点加、模加、模乘、模逆算法模块,实现了高效的ECC点乘操作。实验结果表明,所提出的优化设计有效地缩减了FPGA的LUT逻辑资源,并提高了ECC点乘运算的计算速度。

轨道交通车辆系统RAMS管理技术应用研讨

轨道交通是人们交通出行的主要方式之一,同时也是交通事业建设的重点内容,如何保证轨道交通车辆安全运行,做好车辆系统安全管理至关重要。RAMS管理属于主动性隐患管理工具,将其投入到轨道交通车辆系统中,能够及时发现和消除安全隐患,最大程度上提升轨道交通车辆安全性和可靠性。尽管当前国内多数轨道交通车辆系统中开始运用RAMS管理进行可靠性、安全性管理,但却面临着相关主体单位的RAMS管理意识薄弱的问题,种种问题还有待进一步完善。本文就轨道交通车辆系统RAMS管理技术应用情况展开分析,并分析轨道交通车辆安全性、可靠性和可维修性内容,提出合理的控制手段付诸实践。