印制电路板的电磁兼容问题研究

主要介绍了在设计印制电路板时需要考虑的电磁兼容问题，并说明产生问题的原因。     

钢铁制件快速发蓝工艺的研究

钢铁制件采用高温（１４５—１５５℃）碱性氧化法,钢铁件表面经过氧化,其表面形成一定厚度的氧化膜,呈现一种特殊的氧化色－蓝黑色所以一般称为“发蓝”。钢件制件这层氧化膜,色泽美观,无氢脆,有弹性,膜层薄,不影响精度,对消除热处理后生成的应力也有一定作用。发蓝是钢铁制件防锈一种常用方法。碱性氧化法工艺始于１９３９年,至今有６０年历史。该工艺耗能大、用烧碱、亚硝酸钠等污染环境。因此科技工作者探索新的方法来取代它,１９８７年美国首先推出了室温发蓝液专利产品,１９９０年我国开发了许多常温发蓝液产品,形成膜以磁性氧化铁（Ｆｅ３Ｏ４）为主黑膜即发蓝膜。笔者加适量的促进剂使钢铁制件,在室温下,快速（６０～９０ｓ）发生微电极反应而形成黑亮的氧化膜。     

《印制电路板设计》课程的翻转课堂教学模式研究

《印制电路板设计》是自动化一门培养学生实践动手能力的课程,本文探究了该课程基于翻转课堂的新型教学模式,制定了翻转课堂的具体实施过程,并在教学实践中对教学效果进行了评估。实践结果表明该教学模式能有效提高学生的参与度和自信心,激发学生的学习热情,更有利于教师因材施教,取得了良好的教学效果。     

加油车铝罐焊逢缺陷渗油的补焊工艺

飞机加油车铝罐的材质是防锈铝合金,且盛放介质有相当长的时间,如果没有严格补焊工艺保证的情况下,会有很大的危险性,因为它的补焊工艺,即要考虑防锈铝的焊接性,又要考虑介质性质,在此介绍一种防止渗油的补焊工艺。     

基于小型工业制板系统的PCB制作与研究

本文简单介绍了小型工业制板系统,总结了用小型工业制板系统制作双面板及单面板的制板流程及注意事项,并指出将其引入实验室的必要性。     

软包装凹印制版工艺数字化控制集成研究

凹印制版工艺数字化控制,由电子文件图像色彩数字化控制、滚筒加工制造标准化、电子雕刻数字化控制、印刷打样数字化等集成,从而规范凹印版辊制造工艺,确保制造过程的稳定性,提高凹印版辊质量。     

生日蛋糕的制作工艺研究

随着人们生活水平的提高和消费观念的转变,生日蛋糕也走进了千家万户,点缀着人们的快乐生日.介绍了生日蛋糕的起源、分类,并以戚风蛋糕体的水果蛋糕为例阐述了生日蛋糕的制作工艺及技术要点,并分析了生日蛋糕在我国的发展前景.     

黑龙江黑陶制作工艺研究

黑龙江黑陶艺术是中华之瑰宝,其艺术品均为精选泥料、严格调制、精雕细琢、高温炭化、古法烧制而成,造型丰富、形象独特,具有明快节奏感、韵律感的纹饰体现了形意统一和黑陶制品新的艺术内涵.而黑龙江黑陶制作工艺研究对于中华思想文化的继承具有极高的价值.     

芦苇画制作工艺研究

芦苇画艺术主要以野生芦苇的叶、秆、花穗为原料,经过整料、剪贴、熨烫、描画、粘贴、装裱等十几道工序精心创作而成,本论文详细论述芦苇画制作工艺要点及芦苇画艺术特色.     

Vacuum pyrolysis characteristics of waste epoxy printed circuit boards

Vacuum pyrolysis was employed to dispose scrap brominated epoxy printed circuit boards (PCBs). Pyrolysis characteristics of waste PCBs under normal pressure and vacuum were investigated in this paper. A detailed study on the analysis of the elemental composition of PCBs and the pyrolysis products was performed. The thermal decomposition kinetics was measured by a thermogravimetric (TG) analyzer. The activation energy of pyrolysis under nitrogen atmosphere and vacuum were 193 kJ/mol to 206 kJ/mol and 145 kJ/mol to 165 kJ/mol, respectively. The composition of materials was analyzed by elemental analyzer. The pyrolysis products were analyzed by GC (gas chromatograph), GC-MS (chromatography and mass spectrometry) and FT-IR (Fourier transform infrared spectroscopy). Vacuum helped to increase the yield of pyrolysis oil. The liquid yield of PCBs pyrolysis at 15 kPa and normal pressure were 31.3? and 23.5?, respectively. The main components in pyrolysis oils were phenol, isopropyl-phenol, and their brominated substitution.     

Recovering metals from printed circuit board scrap by a mechanical separation process

A mechanical separation process was developed for recovering metals from printed circuit board （PCB） scrap; it included three steps： impact crushing, sieving and fluidization separation. The mechanism of the technique was based on the difference in the crushabilities of metallic and nonmetallic materials in the PCBs that led to the concentrated distribution of metals in particles of larger sizes and nonmetals mostly in particles of smaller sizes. It was found that crushed PCB particles from 0.125 mm to 1.000 mm contained about 80% of metals in the PCBs. Metals acquired satisfactory liberation in particles smaller than 0.800 mm. The crushed PCB particles were sieved into fractions of different size ranges. Each fraction separately went through a gas-solid fluidized bed operating at a selected optimal gas velocity for the specific size range. Approximately 95% of metals in printed circuit board particles from 0.125 mm to 0.800 mm was recovered by the gas-fluidized bed separator at the selected optimal gas velocity. However, separation of metals from particles smaller than 0.125 mm was not satisfactory. Further study is needed on metal recovery from fine particles.     

高速ADC电路的电磁兼容设计

针对高速ADC电路设计的特点，重点讨论了包含高速ADC的硬件电路设计中印刷电路板布局时所必须引起注意的电磁兼容问题，包括数字地和模拟地、数字电源和模拟电源的隔离，ADC输入信号、输出信号的处理以及采样时钟的处理等，并给出了一个成功布局的例子。     

一种新的印刷电路板浸银镀速的测定方法

利用先进的电化学系统,通过测定铜-银电偶电流,分别对有无络合剂条件下印刷电路板浸镀银的沉积速度进行测定,并将测定结果与常规的容量滴定法进行对比.结果表明,与常规的容量滴定法相比,采用电偶电流法测定浸镀银的沉积速度,不仅直观、方便、速度快,而且能进行在线检测,有利于及时对印刷电路板的浸银工艺进行调整.     

关于"Protel 99 SE"教学的探讨

探讨学生在学习Protel 99 SE时易犯的一些错误,以及教师在教学中应注意的几点问题。     

Surface breakdown of printed circuit board under magnetic field with reduced pressure

Epoxy resin laminate onto which a pair of copper foil was printed was employed as test samples.The samples were placed in an artificial atmospheric chamber, which was vacuumed by a rotary pump from 100 kPa to 5 kPa.The magnetic field was produced by permanent magnets that were assembled to make E×B drift away from, into and parallel to the sample surface, respectively.Magnetic flux density was adjusted at 120 mT, 180 mT and 240 mT respectively.By applying a negative bias voltage between the electrodes, the time to surface breakdown was recorded.Obtained results show that when E×B is into the surface, the time to the breakdown is shortened;when E×B is away from the surface, the time to the breakdown is delayed;when E×B is parallel to the surface, the time to the breakdown remains approximately the same as the case without magnetic field.With the decrease of pressure, the time to the breakdown increases and the effect of magnetic field on breakdown appears to be strengthened.     

运用物理雕刻的线路板制作系统的研制

首先介绍了传统的印制电路板的制作方法，接着介绍了自主开发的基于物理雕刻的PCB制作系统的原理，该系统把用户定义的PROTEL文件通过计算机控制输出到雕刻机，在空白的覆铜板上把不必要的铜泊铣去，形成用户定制的线路板，非常适合电子类学校进行线路板制作的课程实验。     

Protel 99 SE在电路设计中的应用

随着计算机技术的发展,计算机软件在电路设计中的应用越来越广泛。文章以Protel为例,介绍其在电路原理图和印刷电路图设计中的应用方法,并探讨了该软件在设计过程中常遇到的问题及其解决办法。     

印刷线路板回收工艺研究

从印刷线路板组成材料的复杂性入手,结合中国电子废弃物的产生现状说明了印刷线路板回收利用的重要意义.分析了现在常用的几种线路板回收工艺的主要特点,并重点介绍了机械物理法、化学法和热裂解法的工艺特点,相关研究现状与发展趋势.     

印制线的传输特性研究

利用传输线理论定量分析印刷电路板印制线的传输特性 ,为印刷电路板的布线设计提供依据 .