电源是怎样“烁”成的

电源的技术含量远没有主板和显卡那么高，但其重要性却不容忽视。劣质电源不仅会损坏硬件，还可能造成人身伤害……想了解一款合格电源是怎样生产出来的么？本刊记者将带您深入电源生产工厂。     

Preparation and properties of 4.25Cu-0.75Ni／NiFe2O4 cermet

4.25Cu-0.75Ni/NiFe₂O₄ cermets were prepared by doping NiFe₂O₄ ceramic matrix with the mixed powders of Cu and Ni or Cu-Ni alloy powder as the electrical conducting metallic elements. The effects of technological parameters, such as the adding modes of metallic elements, the ball milling time, the sintering time and the sintering temperature, on the relative density and resistivity of the cermets were studied. The results show that the resistivity of 4.25Cu-0.75Ni/NiFe₂O₄ cermets decreases with increasing temperature, and has a turning point at 590 °C, which is similar to that of NiFe₂O₄ ceramic. The sintering temperature and adding modes of metallic elements have a great influence on the properties of 4.25Cu-0.75Ni/NiFe₂O₄ cermets. When the sintering temperature increases from 1200 °C to 1300 °C, the relative density increases from 89.86% to 95.33%, and the resistivity at 960 °C decreases from 0.11 Ω · cm to 0.03 Ω · cm, respectively. When the metallic elements are added with the mixed powders of Cu and Ni, the cermets of finely and uniformly dispersed metallic phase, high density and electric conductivity are obtained. The relative density and resistivity at 960 °C are 90.23% and 0.04 Ω · cm respectively for the cermet samples sintered at 1200 °C for 2 h, which are both better than those of the cermets prepared under the same technique conditions but with the metallic elements added as 85Cu-15Ni alloy powders. Foundation item: Project (G1999064903) supported by the National Key Fundamental Research and Development Program of China; project(2001AA335013) supported by the National High Technology Research and Development Program of China; project (50204014) supported by the National Natural Science Foundation of China     

Preparation of Plate Fe60 Co8 Zr10 Mo5 W2 B15 Bulk Amorphous Alloy and Its Fracture Toughness

With processes of arc melting, inductive melting and copper mold suction casting, a plate Febased bulk amorphous alloy Fe₆₀Co₈Zr₁₀Mo₅W₂B₁₅ with a thickness of 1 mm was prepared. The surfaces and fractures of the cast bulk amorphous alloy were aglean and with typical metallic luster. The glass transition temperature (T_g), supercooled liquid region (δT_x) and reduced glass transition temperature (T_g) of prepared Fe-based amorphous alloy are 884 K, 63 K, and 0.611 respectively. The fracture toughness of the cast bulk amorphous alloy is at the level of 1.6 MPa·m^1/2. Funded by the Key Project of National Natural Science Foundation of China (No. 50431030) and the Natural Science Foundation of Jiangsu Province (No. BK2001053)     

修配法解装配尺寸链分析

修配法是解装配尺寸链的重要方法。本文主要分析补偿环修配时,使封闭环变大和变小的两种情况。由于采用修配法解装配尺寸链,各组成环按经济加工精度制造,这样封闭环的极值公差超出封闭环公差,必须精确地确定补偿环的预加工尺寸。为此本文还推导出计算补偿环预加工尺寸和补偿量的普遍公式。     

冲裁模具线切割加工中的工艺要点分析

根据冲模零件线切割加工的工艺特性,分析间隙补偿量的确定方法,通过合理选择穿丝孔的位置以及切割路线,对凸、凹模采取预加工工艺,有效减小加工过程中工件的变形。针对塌角,提出工艺改善措施,并分析了凸、凹模一次成形的加工方法,提高了工件切割质量及效率。     

两种不同造纸法再造烟叶加工处理方式比较

为验证“黄山(精品)”制丝线造纸法再造烟叶加工处理工艺流程设计,从工艺流程、温度及含水率稳定性、掺配及加料均匀性、理化指标和感官质量5个方面对同步加工与预加工进行了比较.结果表明:①同步加工具有工艺流程简洁、操作简便、投资小、生产组织时间短等优点,不足之处在于含水率稳定性、掺配及加料均匀性较差,而预加工相反;②与同步加工相比,经预加工处理后,卷烟物理指标、烟丝常规化学成分及感官质量无明显变化,批内卷烟烟气焦油、烟碱、一氧化碳释放量稳定性有所提升.     

翻孔预孔孔径的计算

根据塑性变形体积不变原则和翻边变形的力学特点,探讨了翻孔预孔孔径的计算方法,分析了现有的按弯曲件展开原则计算翻孔预加工小孔孔径方法的欠妥之处,提出了一个更合理的计算公式。     

发动机缸体预加工自动生产线工艺分析

为提高发动机缸体加工的自动化程度,最大限度减少生产线操作人员,降低人为因素产生的质量风险,通过对工件各面孔系及其结构特点分析,设计研制了机加工工序集中程度较高的铝合金缸体预加工生产线,选用双交换台卧式加工中心实现在一台设备上完成全部预加工内容,并采用关节机器人实现机床自动上下料;其它清洗、检漏工序也按物料自动识别自动行...     

秸秆怎么发电？

秸秆发电是生物质能发电的一种形式,通过在高温高压锅炉中直接燃烧经过预加工的秸秆产生热能,再进一步转化为电能。秸秆是一种很好的清洁可再生能源,每两吨秸秆的热值就相当于一吨标准煤,而且其平均含硫量只有3．8‰,而煤的平均含硫量约达1％。