非抑制型离子色谱法测定印制电路板表面阳离子污染物

本文提出了一种利用非抑制型离子色谱法测定印制电路板表面五种无机阳离子污染物的方法。样品用异丙醇水溶液提取后,用Sep-PakC18小柱净化试样,用离子色谱分离,电导检测器检测。五种阴离子的检测限介于0.01~0.02μg/ml之间,回收率为98~103%。方法准确、可靠,可用于印制电路板洁净度的评价分析。     

离子色谱法测定饮用水中常见阴离子

本文主要介绍离子色谱法检测饮用水中常见阴离子的方法。本方法采用瑞士万通的761型离子色谱仪。分离柱为METROSEPAnionDual2,淋洗液为2.0mmol/LNaHCO3和1.3mmol/LNa2CO3抑制液为20mmol/LH2SO4在测定范围内,F-、Cl-、NO2-、NO32-;-SO42-的峰面积和质量浓度呈线性关系,相关系数均大于0.999。回收率F-为101.5%,CL-O101.6%,NO2-为108.0%.NO32-为97.7%,SO42-为103.3%。相对标准偏差在0.7%-4.3%之间。     

离子色谱法测定石墨烯中水溶性阴离子含量

建立石墨烯粉体中氟离子(F~–)、氯离子(Cl~–)、亚硝酸根离子(NO₂~–)、溴离子(Br~–)、硝酸根离子(NO₃~–)、硫酸根离子(SO₄^2–)和磷酸根离子(PO₄^3–)的离子色谱分析方法。石墨烯样品冷冻研磨后,加入超纯水超声提取,过0.22μm聚醚砜滤膜,以IonPac AS11-HC阴离子色谱柱进行分离,8～40.0 mmol/L KOH淋洗液梯度洗脱,采用电导检测器检测,外标法定量。结果表明,7种阴离子的峰面积与其质量浓度在一定范围内呈现良好的线性关系,检出限和定量限分别为0.001～0.06 mg/L和0.003～0.198 mg/L,相对标准偏差为0.5%～5.7%(n=6),回收率在94.0%～104.0%之间。     

离子色谱法同时测定饮用水中四种阴离子

本文以离子色谱法同时测定了地下水中4种阴离子。结果表明,将水样经微滤过滤处理后连续进样,利用离子色谱仪可同时测定F-、Cl-、NO3-和SO42-四种阴离子。该方法具有灵敏、准确、快速和简便等优点,可用于生活饮用水中阴离子的同时分析,有较高的实用价值。     

离子色谱法测定降水中阴离子校准曲线评价指标研究

为实现实验室内部质量控制目标,进一步完善大气降水中4种阴离子校准曲线斜率、截距质量控制指标体系。本文通过对实验获得的大气降水中4种阴离子校准曲线斜率、截距的数据进行统计分析和建立平均值-标准偏差控制图,并应用于校准曲线的质量控制,得出质量控制评价指标范围的建议值。结果表明,离子色谱法测定大气降水中4种阴离子校准曲线斜率、截距质量控制评价指标范围的建议值分别如下：斜率为F^- 0.239～0.287、Cl^- 0.169～0.199、NO₃^-0.082～0.094、SO₄^2-0.119～0.137,截距为F^--0.0074～0.0058、Cl^--0.0382～0.0092、NO₃^--0.0139～0.0065、SO₄^2--0.0138～0.0150。     

离子色谱法测定水中部分阴离子含量的测量不确定度评定

为了对用离子色谱法测定水中部分阴离子（氟、氯、硝酸盐、硫酸盐）的测量方法进行系统研究，通过分析测量中可能导致不确定度的来源，对测量结果进行不确定度评定．使测量结果更加完整，以提高离子色谱法测定水中部分阴离子含量的准确度。     

反相高效液相色谱法分离分析水中一些阴离子

本文试验反相高效液相色谱法分离分析水中氯离子、硝酸根和硫酸根的条件,研究可能干扰、提高选择性和提高灵敏度的方法,建立应用于自来水和海水等实际样品的分离分析方法。     

离子色谱法测定面粉中的溴酸盐

采用离子色谱法测定面粉中的溴酸盐,选用M etrohm 861型离子色谱仪,Metrosep Asupp5-250阴离子分析柱,以3.2mmol/LNaCO3+1.0mmol/LNaHCO3溶液为淋洗液(流动相)。标准曲线的线性范围为0.2~1.2mg/L(r=0.999807),BrO3-的检出限为0.02mg/L(进样体积20μL),相对标准偏差为1.173%,用本方法测定面粉样品,加标回收率在91.9%以上。实验表明,本方法快速、准确,灵敏,重复性较好,结果令人满意。     

ICS-900型离子色谱仪测定水样阴离子时温度对曲线峰值偏移影响的分析

离子色谱法是利用离子交换的分离原理,连续对多种阴离子进行定性和定量分析。具有操作简单、启动快速、性能可靠稳定、能多种离子同时测定。本文阐述了在不同温度下阴离子曲线峰值出现时间偏移的问题。     

离子色谱法测定面粉中的溴酸盐

采用离子色谱法测定面粉中的溴酸盐,选用Metmhm861型离子色谱仪,Metmsep Asupp 5—250阴离子分析柱,以3．2mmol／LNaCO3＋1．0mmol／LNaHCO3溶液为淋洗液（流动相）。标准曲线的线性范围为0．2～1．2mg／L（r=0．999807）,BrO3^-的检出限为0．02mg／L（进样阵积20μL）,相对标准偏差为1．173％,厢本方法测定面粉样品,加标回收率在91．9％以上。实验表明,本方法快速、准确,灵敏,重复性较好,结果令人满意。     

Recovery of copper from printed circuit boards scraps by mechanical processing and electrometallurgy

The constant growth in generation of solid wastes stimulates studies of recycling processes. The electronic scrap is part of this universe of obsolete and/or defective materials that need to be disposed of more appropriately, or then recycled. In this work, printed circuit boards, that are part of electronic scrap and are found in almost all electro-electronic equipments, were studied. Printed circuit boards were collected in obsolete or defective personal computers that are the largest source of this kind of waste. Printed circuit boards are composed of different materials such as polymers, ceramics and metals, which makes the process more difficult. However, the presence of metals, such as copper and precious metals encourage recycling studies. Also the presence of heavy metals, as Pb and Cd turns this scrap into dangerous residues. This demonstrates the need to search for solutions of this kind of residue, in order to have it disposed in a proper way, without harming the environment. At the first stage of this work, mechanical processing was used, as comminution followed by size, magnetic and electrostatic separation. By this process it was possible to obtain a concentrated fraction in metals (mainly Cu, Pb and Sn) and another fraction containing polymers and ceramics. The copper content reached more than 50% in mass in most of the conductive fractions and significant content of Pb and Sn. At the second stage, the fraction concentrated in metals was dissolved with acids and treated in an electrochemical process in order to recover the metals separately, especially copper. The results demonstrate the technical viability of recovering copper using mechanical processing followed by an electrometallurgical technique. The copper content in solution decayed quickly in all the experiments and the copper obtained by electrowinning is above 98% in most of the tests.     

Conversion of bromine during thermal decomposition of printed circuit boards at high temperature

The conversion of bromine during the thermal decomposition of printed circuit boards (PCBs) was investigated at isothermal temperatures ranging from 800°C to 1100°C by using a quartz tube furnace. The influence of temperature, oxygen concentrations (0%, 10% and 21% in the nitrogen-oxygen atmosphere) and content of steam on conversion of bromine was studied. With the increment of temperature, the conversion from organic bromine in the PCBs to inorganic bromine in the gaseous fraction increased from 69.0% to 96.4%. The bromine was mainly evolved as HBr and Br(2) in oxidizing condition and the Br(2)/HBr mass ratio increased at stronger oxidizing atmosphere. The experimental results also indicated that the existence of steam can reduce the formation of Br(2). Furthermore, co-combustion of PCBs with S and CaO, both as addition agents, was investigated, respectively. In the presence of SO(2), Br(2)/HBr mass ratio obviously decreased. Moreover, the utilization of calcium oxide can efficiently promote the conversion of organic bromine to inorganic bromine. According to the experimental results, incinerating PCBs at high temperature can efficiently destroy the organobrominated compounds that are considered to be possible precursors of polybrominated dibenzeo-p-dioxins and dibenzofurans (PBDD/Fs), but the Br(2) and HBr in flue gas should be efficiently controlled.     

The role of SPC in printed circuit board manufacture

This paper reports on research which examined the use of statistical process control (SPC) in the quality improvement process of a printed circuit board (PCB) manufacturer. The implementation of SPC is discussed along with the difficulties encountered and benefits achieved. The findings indicate that SPC is a tool which can be of considerable assistance in the quality improvement process of PCB manufacture. However, the variety of manufacturing technologies used and the number of interconnecting processes makes the application of SPC more difficult than in other traditional industries. The lessons learned include that the introduction of SPC must not be rushed, that discipline and support from all levels in the organization are crucial to its success, that SPC cannot be used in isolation—it needs the structure of a continuous improvement initiative, and that getting processes in a state of statistical control and capable, and keeping them there, is a difficult task which involves considerable effort and patience.     

Integer programming approach to the printed circuit board grouping problem

A printed circuit board (PCB) grouping problem arising from the electronics industry is considered. Given a surface-mounting device with a number of component feeders and several types of PCBs to be produced, the problem is how to group the PCBs so that the total set-up time for component feeders is minimized. The problem is formulated as an integer-programming problem and a column generation approach is proposed to solve it. In this approach, the original problem is decomposed into a master problem and a column-generation subproblem. Starting with a few columns in the master problem, new columns are generated successively by solving the subproblem optimally. To solve the subproblem, a branch-and-cut approach is used. To solve the master problem, a branch-and-bound algorithm is used with the generated columns. However, a branching strategy is also proposed that maintains consistency in the column-generation procedure after branching. Computational experiments show that the solution approach gives high-quality solutions in reasonable computing time.     

Optimization of printed circuit board interconnectivity testing for parallel devices

In this article, the problems of test sequence generation and scheduling optimization for a tester with parallel devices are considered in order to reduce inspection times. Two optimization problems are formulated for test sequence generation and the scheduling of parallel devices, and then algorithms to address these problems are proposed. The proposed algorithms were tested via simulation and experiments. The test results show two to four times improvement over existing methods.     

A GA-based solution approach for balancing printed circuit board assembly lines

Printed circuit board (PCB) assembly lines consist of a number of different machines for mounting electronic components onto PCBs. While high-speed placement machines are employed to assemble standard components, so-called fine-pitch placement machines are used to mount complex electronic components with high precision and by use of specific nozzles. In this paper, we investigate a typical mass production environment where a single type of PCB is assembled in a line comprising high-speed as well as high-precision placement machines. The PCB assembly line balancing problem consists of assigning component feeders, each holding a specific electronic component type, and the corresponding placement operations to machines in the line so as to minimize the assembly cycle time. To solve this problem, a two-stage solution procedure based on genetic algorithm (GA) is proposed. In the first stage, component feeders are assigned to the placement machines with the objective of balancing the workload within the assembly line. A number of candidate solutions are then transmitted to the second stage, where specific machine optimization algorithms are applied to determine the feeder-slot assignment in the component magazine of the machines and the placement sequence of the various components. As a result, fine-tuned placement operation times are achieved which reflect the individual operation mode and the actual component setup of the placement machines. Finally, from the candidate solutions the one which minimizes the actual PCB assembly time is selected.     

Inkjet printing and adhesion characterisation of conductive tracks on a commercial printed circuit board material

Silver nanoparticle-based conductive tracks were inkjet printed using a piezoelectric drop-on-demand inkjet printer on a commercially available electronics grade fibre glass (E-glass) reinforced substrate material, and the experimental results have been summarised. Ink jetting was done on two variants of this substrate material, viz. etched and unetched, to determine the influence of substrate surface topography on adhesion and accuracy of the printed tracks. The pull-off adhesion test method was used to quantify adhesive strength. The dependence of the pull-off test results on local geometry of the test area are illustrated with the aid of scanning electron microscope images and interferometer studies. Based on the outcomes of the experiments, conclusions concerning the suitable surface topography for inkjet printing have been arrived at.     

废弃电路板真空热解产物特性分析

采用真空热解对废弃电路板进行热解实验,利用FT-IR分析、GC/MS、SEM等技术对真空热解液体、固体及气体产物进行了分析表征,研究了不同真空条件和温度下对热解产物的组成和理化特性.结果表明,液体产物的密度会随着真空度的变化发生改变;在不同真空条件下,产物的组成也有不同,并分析其产生的原因.为进一步探讨废弃电路板的真空热解产物特征提供参考.     

基于废弃印刷线路板中非金属的复合板材制备

随着废弃电子电器产品的快速增长带来的环境问题日趋严重,废弃印刷线路板的资源化问题一直成为关注的焦点。着重研究了气流分选后得到的废弃印刷线路板非金属粉碎料的资源化再生制板材的可行性,探讨了不同填料粒径、投加量和改性剂下所得复合材料拉伸强度、弯曲和冲击强度的变化。研究表明以马来酸酐接枝聚丙烯（MAH-g-PP）作为改性剂,聚丙烯S700为基体树脂,在粒径范围为0.125～0.3mm的非金属粉碎料添加量为20%的条件下,板材力学性能较优,具有广泛的应用前景。     

Productivity measurement of the manufacturing process for outsourcing decisions: the case of a Taiwanese printed circuit board manufacturer

Outsourcing is used to alleviate capacity shortages and increase production flexibility. Generally, the outsourcing decision of manufacturing processes is determined by the capacity utilization rate and focus on individual process. In this article, multicriteria are considered by applying the data envelopment analysis to evaluate the relative efficiencies of all the manufacturing processes to help to assess the allocation of a company's resources. The Malmquist productivity index (MPI) is further employed to measure the productivity changes of each process, on which the outsourcing decision can be based. The empirical case of a Taiwanese printed circuit board manufacturer is applied to illustrate the outsourcing decision process. According to the outsourcing decision matrix proposed in this article, the manufacturing process with low efficiency score and MPI value was identified as a high priority for outsourcing. The outcome shows that the manufacturing process with a higher investment of fixed assets does not guarantee better efficiency. If a company follows the outsourcing decision suggested by the proposed approach, the capacity utility rate and the production quantity per person can be increased. The results and analysis model can provide an alternative for managerial thinking and practical application for outsourcing decisions.