斜拉桥成桥状态的影响参数分析

以杭州湾跨海大桥南通航孔道斜拉桥为工程背景,采用对比分析的方法,定量分析了结构自重、临时荷载、结构刚度等因素对斜拉桥成桥状态的影响,结果表明主梁自重、施工临时荷载对桥的索力、主梁挠度,影响较大,其中临时荷载的影响尤为明显,而结构刚度的影响较小,斜拉索张拉力误差对主梁竖向累计位移和前端索力的影响较明显。     

新型高速钢丝圈成型机床控制系统设计

设计了一种适用于新型高速钢丝圈成型机床的控制系统,系统整体由供料系统、送丝系统、成型系统、人机交互系统和反馈报警系统组成,以可编程控制器PLC为控制核心,伺服电机和异步电机为动力源,利用同步带传动替换传统凸轮传动;利用模糊位置定位算法保证钢丝圈冲裁长度的一致性,通过控制输出频率实现成型主轴无级变速与高速运转;以触摸屏为...     

导电聚氨酯泡沫材料研究进展

从使用不同导电填料（炭黑、碳纳米管、石墨、金属、有机填料等）制备导电聚氨酯泡沫（PUF）材料的角度进行分析,总结了添加不同导电填料的复合泡沫制备方法以及对泡沫材料性能的影响,并论述了导电PUF材料在压阻材料、吸波材料、电磁屏蔽材料以及电极材料等领域的应用。分析表明,通过添加导电填料,可以改善PUF的静电现象,提高防静电、导电等性能并拓宽PUF材料的应用领域。     

Thermal resistance of polyurethane adhesives containing aluminum hydroxide and dealkaline or alkaline lignin

For the sustainability of the polyurethane resin (PUR) industry, petroleum-based materials must be replaced with renewable resource and economic aspects must be considered. Lignin is a renewable, thermostable biomass consisted with a phenolic polymer. As a thermostable bio-filler for PUR adhesives, acidic or basic lignin was blended with an amphiprotic inorganic filler, to reduce the resins and product costs due to cheap, unmodified materials. The thermal resistance of the PUR adhesives was evaluated by measuring adhesion before and after heating and with and without a mechanical effect caused by substrate penetration. The results show that after heating at 200°C, the PURs containing 7.5 or 15 wt% of dealkaline lignin or 7.5 wt% of alkaline lignin decomposed more slowly than the lignin-free PUR. The properties of the PURs were also analyzed using Fourier-transform infrared spectroscopy and differential scanning calorimetry. Additionally, the PURs containing over 30 wt% of dealkaline lignin show potential as environmentally friendly water-blown PUR foams.     

In situ growth of SiC wires on CVI densification of SiC foam

Silicon carbide (SiC) foam prepared by polymer infiltration and pyrolysis (PIP) process was further densified with β-SiC by chemical vapor infiltration (CVI) technique. Scanning electron microscopy and high-resolution transmission electron microscopy images confirmed the presence of highly entangled and branched in situ grown SiC wires of uniform diameter (∼500 nm) over the struts of open-cell SiC foam. A uniform rate increase in diameter from nanometer to micron range (∼11 μm) was observed with an increase in the CVI reaction period. X-ray diffraction results showed the formation of highly crystalline β-SiC structure along the <111> direction with stacking faults. The formation of SiC wires was explained by the vapor–liquid–solid mechanism and evenness of the surface and uniform growth rate of SiC confirmed the homogeneous concentration of gaseous species during CVI reaction. The compressive strength increased with relative density, with maximum values of 5.5 ± 1.26 MPa for ultimate SiC foam (ρ = 400 kg/m³) prepared by hybrid PIP/CVI technique. The thermo-oxidative stability of the resultant foam was evaluated up to 1650°C under air and shows excellent thermal stability compared to SiC foam prepared by PIP route. The densified SiC foam can find potential applications in the field of hot gas filters, catalyst supports, microwave absorption properties, and heat insulation for high-temperature applications.     

温瓶处理对纯生啤酒泡沫稳定性的影响研究

在温度不断提高的情况下，纯生啤酒中蛋白酶A及蔗糖转化酶的活力都呈下降趋势，但蔗糖转化酶对温度升高的抵抗力比蛋白酶A强，在蛋白酶A失活的临界点，蔗糖转化酶仍能保持约35％的活力。实验发现，在灌装过程中，对成品纯生啤酒采用60℃、2．5min的“温瓶”处理，可在部分保留蔗糖转化酶活力的同时，将蛋白酶A的活力降低到最低限度，有效地防止纯生啤酒泡沫稳定性的衰减。温瓶操作既可保持纯生啤酒的新鲜度，又可防止其泡持性的衰减。     

织物应用效果模拟技术的探讨

织物应用效果模拟是当今织物CAD系统的发展方向，文章讨论了基于原始图片的织物应用效果模拟技术，提出一种建立映射曲面控制点的简便方法，基本实现织物应用化逼真的视觉模拟效果。该软件的开发对指导实际生产有很大的现实意义。     

平静葡萄酒泡沫研究

以平静红葡萄酒为研究对象，采用气相色谱等分析方法研究了该酒的泡沫成分，研究结果表明：某泡沫挂杯严重的原装葡萄酒顶空气样中ＣＯ２含量占５７％，其它成分主要为Ｎ２，说明平静葡萄酒泡沫的主要成分为ＣＯ２。本文对泡沫产生的原因和去除方法进行了探讨。     

4400 mm牛皮挂面纸板机的典型配备

本文概括介绍了这台造纸机各个部分的配置和特点。     

聚酯网水平方向和垂直方向冲洗的实验比较

造纸机网部高压冲洗是保证聚酯网滤水性能和使用寿命的一项重要操作。冲洗方向的选择对高压冲洗效果有着至关重要的影响。本文在实验的基础上，对上述操作因素进行了研究。