J427GR电焊条的研究

采用正交设计和方差分析的方法，通过适当提高熔渣的碱度，控制熔敷金属中合金元素的含量及配比，加入微量元素，成功研究出熔敷金属扩散氢含量低、塑性和低温韧性高、焊接工艺性能好的J427GR电焊条；适用于焊接对低温冲击韧性要求高的重要焊接结构。     

船舶中高频组合电台常见故障分析及对策探究

文章分类列举了船舶中高频组合电台功放单元、稳压电源、收发天线、天线调节单元、充放电电路和设备接地部分常见故障,从专业技术角度对故障原因进行分析,并针对当前船员有关GMDSS设备维修技术相对薄弱的实际,从维护保养方面提出对策建议,努力降低中高频组合电台故障发生几率,保障船舶安全。     

Thermal Transport in Nanoporous Yttria-Stabilized Zirconia by Molecular Dynamics Simulation

Yttria-stabilized zirconia (YSZ) is widely used as thermal barrier coatings (TBCs) to reduce heat transfer between hot gases and metallic components in gas-turbine engines. Porous structure can generally reduce the lattice thermal conductivity of bulk material, so porous YSZ can be potentially used as TBCs with better thermal performance. In this work, we investigate the thermal conductivity of nanoporous YSZ using the nonequilibrium molecular dynamics (NEMD) simulation, and comprehensively discuss the effects of cross-sectional area, pore size, structure length, porosity, Y₂O₃ concentration and temperature on the thermal conductivity. To compare with the results of the NEMD simulation, we solve the heat diffusion equation and the gray Boltzmann transport equation (BTE) to calculate the thermal conductivity of the same porous structure. From the results, we find that the thermal conductivity of YSZ has a weak dependence on the structure length at the length range from 10 to 26 nm, which indicates that the majority of heat carriers have very short mean free path (MFP) but there exists small percentage (about 3%) of phonons with longer MFP (larger than 10 nm) contributing to the thermal conductivity. The thermal conductivity predicted by NEMD simulation is smaller than that of solving heat diffusion equation (diffusive limit) with the same porous structure. It shows that the presence of pores affects phonon scattering and further affects the thermal conductivity of nanoporous YSZ. The results agree well with the solution of gray BTE with a average MFP of 0.6 nm. The thermal conductivity of nanoporous YSZ weakly depends on the Y₂O₃ concentration and temperature, which shows the phonons with very short MFP play the major contribution to the thermal conductivity. The results help to better understand the heat transfer in porous YSZ structure and develop better TBCs.     

不该发生的船舶触礁?

一、事故概况 2013年1月11日约1654时,X轮装载23 953吨煤炭从北仑二期1 #泊位驶往乌沙山电厂途中,在双屿门航道内发生触礁(概位29° 43′ 17″N/122° 02' 20″E),导致艏尖舱、右舷1 #-3#压载舱及相关管弄破损,海水经由管线弄水密门进入机舱.约1840时,该轮在六横岛西南侧水域(29° 40' 56″N/122°01 ′ 27″E)抢滩坐底.事故直接经济损失约260万,构成一般等级水上交通事故.     

建立船舶设计技术参数参照体系研究

节能减排的要求对船舶设计产生了重大影响,船舶设计理念发生了变化。通过建立船舶资料库,分析船舶设计关键技术参数影响因素,充分发挥业界专家技术把关作用建立船舶设计技术参数参照体系,目的在于对业界进行顶层技术引导,把握船舶设计发展趋势,为船型升级换代及船型开发提供参考。     

试验仿真模态误差分析

模态分析是研究系统动态特性的一种方法,且广泛应用于汽车工业。目前研究汽车动态特性可以用试验模态分析技术和有限元仿真模态分析技术,但无论哪种分析技术,分析得到的结果必然与实际结构之间存在着误差。工程应用中,必须明确误差来源,以便更准确的分析与了解系统特性。     

基于仿真与工况模拟的电池测试技术的研究及应用

分析当前电池和动力台架测试过程中采用的测试方法和测试设备;通过电池仿真模型和工况测试模型的搭建,并应用于BTS设备,实现了模拟真实工况测试电池和为被测设备提供模拟真实电池的目的。     

船舶电力推进系统运行的仿真

船舶电力推进系统的推进电机单机容量大于发电机单机容量,属于重负载电力系统.建立船舶电力推进系统运行的数学模型,在MATLAB软件平台上对该系统进行仿真运行.对获得的电网电压信号,采用小波变换进行波形分析和特征抽取.仿真实验结果表明,该船舶电力推进系统仿真模型合理有效.     

汽车爪极发电机定子模态分析和固有频率计算

建立爪极电机定子结构的三维有限元模型,利用ANSYS软件对其进行模态分析,计算爪极电机定子的固有频率.结果表明,定子6阶模态对爪极电机噪声和振动的贡献最大.