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The article explores the complexities and controversies surrounding the determination of a product's country of origin in international trade. It discusses the "substantial transformation" test, which is commonly used to determine origin, but suggests that it needs to be updated to account for modern manufacturing processes and intangibles. The article also examines alternative approaches to determining origin, such as value-content rules and process-based rules, but acknowledges their limitations. Overall, the article emphasizes the importance of consistent and predictable rules of origin in international trade. [Extracted from the article]

Our paper develops and tests a research model that proposes that job satisfaction (JSAT), career satisfaction (CSAT) and work engagement (WENG) mediate the effect of psychological contract breach (PCB) on affective organizational commitment (AOC). Data were collected from small-sized hotel employees who occupy frontline positions in three waves in four cities in Ghana. The hypothesized linkages were assessed via structural equation modelling. The empirical data confirmed all the hypothesized relationships. Specifically, PCB had a negative impact on AOC. Additionally, JSAT, CSAT and WENG mediated the effect of PCB on AOC. Discussion of implications of the findings are included in the paper. [ABSTRACT FROM AUTHOR]

Modal reservation (MR) allows both increasing the circuit reliability and implementing the effect of modal filtering. The paper presents the study of a printed circuit board (PCB) with MR with the reference conductor in the form of side polygons. The structure is analyzed by quasi-static simulation, and the minimization of the maximum ultra-wideband pulse amplitudes at the far end of the structure after failures is first estimated. Using the heuristic search, the parameters for the PCB structure before and after failures are obtained. It is shown that, before failures, the maximum amplitude (Umax) does not significantly change under the condition of matching and at fixed values of loads. However, after failures, the Umax changes. For this structure, with increasing delay differences between pulses, Umax after failure 3 increased. It is shown that with obtained values of the geometric parameters, amplitudes of decomposition pulses change differently before and after failures. A prototype of the PCB was designed based on this study. [ABSTRACT FROM AUTHOR]

Terrestrial ecosystems and human societies depend on oxygenic photosynthesis, which began to reshape our atmosphere approximately 2.5 billion years ago. The earliest known organisms carrying out oxygenic photosynthesis are the cyanobacteria, which use large complexes of phycobiliproteins as light-harvesting antennae. Phycobiliproteins rely on phycocyanobilin (PCB), a linear tetrapyrrole (bilin) chromophore, as the light-harvesting pigment that transfers absorbed light energy from phycobilisomes to the chlorophyll-based photosynthetic apparatus. Cyanobacteria synthesize PCB from heme in two steps: A heme oxygenase converts heme into biliverdin IXa (BV), and the ferredoxin-dependent bilin reductase (FDBR) PcyA then converts BV into PCB. In the current work, we examine the origins of this pathway. We demonstrate that PcyA evolved from pre-PcyA proteins found in nonphotosynthetic bacteria and that pre-PcyA enzymes are active FDBRs that do not yield PCB. Pre-PcyA genes are associated with two gene clusters. Both clusters encode bilin-binding globin proteins, phycobiliprotein paralogs that we designate as BBAGs (bilin biosynthesis-associated globins). Some cyanobacteria also contain one such gene cluster, including a BBAG, two V4R proteins, and an iron-sulfur protein. Phylogenetic analysis shows that this cluster is descended from those associated with pre-PcyA proteins and that light-harvesting phycobiliproteins are also descended from BBAGs found in other bacteria. We propose that PcyA and phycobiliproteins originated in heterotrophic, nonphotosynthetic bacteria and were subsequently acquired by cyanobacteria. [ABSTRACT FROM AUTHOR]

The counterfeiting of products is a serious concern for any nation with the increasing activity of counterfeit markets. Anticounterfeiting tags demand low‐cost, unclonable, facile, and ultrafast manufacturing processes. In this study, a laser‐induced carbonization (LIC) technique is employed to produce discrete sizes of LIC spots distributed randomly in an array fashion, as a tag, preferably on a laser wavelength‐sensitive polyimide (PI) film. This technique enables the intrinsic creation of LIC spots in PI without any foreign functional materials, thus avoiding the need for external material. Owing to laser technology, based on the input design and laser processing parameters, the reconfigurable desired output tags can be accomplished in a very short time. Different forms of LIC spots in an optical image are grouped and sorted into three‐level bits based on their sizes and brightness for digitalization. The unique LIC‐based tags can be applied to the flexible printed circuit board industry to address counterfeiting. [ABSTRACT FROM AUTHOR]

Defect inspection is essential in the semiconductor industry to fabricate printed circuit boards (PCBs) with minimum defect rates. However, conventional inspection systems are labor-intensive and time-consuming. In this study, a semi-supervised learning (SSL)-based model called PCB_SS was developed. It was trained using labeled and unlabeled images under two different augmentations. Training and test PCB images were acquired using automatic final vision inspection systems. The PCB_SS model outperformed a completely supervised model trained using only labeled images (PCB_FS). The performance of the PCB_SS model was more robust than that of the PCB_FS model when the number of labeled data is limited or comprises incorrectly labeled data. In an error-resilience test, the proposed PCB_SS model maintained stable accuracy (error increment of less than 0.5%, compared with 4% for PCB_FS) for noisy training data (with as much as 9.0% of the data labeled incorrectly). The proposed model also showed superior performance when comparing machine-learning and deep-learning classifiers. The unlabeled data utilized in the PCB_SS model helped with the generalization of the deep-learning model and improved its performance for PCB defect detection. Thus, the proposed method alleviates the burden of the manual labeling process and provides a rapid and accurate automatic classifier for PCB inspections. [ABSTRACT FROM AUTHOR]

Develop-etch-strip (DES) process in printed circuit board (PCB) manufacturing industries produces wastewater containing high organic nitrogen, in which monoethanolamine (MEA) is the main COD and nitrogen source. This study evaluated feasibility of biological treatment of high concentration MEA-containing acidified DES wastewater collected from a full-scale PCB industry. Batch test results indicated that aerobic conditions attained the highest specific COD degradation rates (6.5–14.6 mgCOD/gVSS/h), anoxic conditions attained second (4.81 mgCOD/gVSS/h), and anaerobic conditions was the lowest (1.3–3 mgCOD/gVSS/h). The anoxic/oxic (A/O) sequencing batch reactor (SBR) with porous polyurethanes carriers, BioNET, was able to treat MEA-containing acidified DES wastewater with 80 % COD removal and 23 % TN removal at influent COD of 300 mg/L, while the A/O continuous stirred tank reactor (CSTR) with BioNET at 8 h of HRT achieved above 96 % COD removal and 78 % TN removal at influent COD of 630 mg/L. The aerobic batch test results indicated that specific COD degradation rates followed a Haldane-type model, suggesting that MEA acts as an inhibitory substrate, especially at concentrations above 2000 mg/L. In addition, MEA inhibited the onset of nitrification, but not specific nitrate production rate, suggesting that MEA may inhibit nitrification by inhibiting expression of amoA gene, based on amoA gene expression results. Finally, the contribution for COD degradation, denitrification and nitrification by BioNET (< 20 %) was lower than that for suspended sludge in the A/O CSTR, suggesting that the role of BioNET carriers could retain microorganisms and served as the habitats for microorganisms to avoid washout at a shorten HRT situation. [ABSTRACT FROM AUTHOR]

In this paper, we present a new microstrip to waveguide transition design for interfacing printed circuit board (PCB) microstrip transmission lines with 3‐D printed metallised‐plastic waveguide components. Compared with traditional metal waveguides, interfacing with plastic‐based waveguides are challenging due to thermal and mechanical constraints. Despite the development of 3‐D printing technology, the precision of 3‐D printed waveguides is not as good as the machined metal counterparts. This is critical for microwave components and must be considered in the design process. To minimise the effect of non‐ideal waveguide components, a design methodology minimising sensitivity to geometrical variations in the 3‐D printed parts is proposed. By sandwiching the PCB between two waveguide sections and optimising the waveguide impedance transformation geometry, the design shows very low insertion loss. It is mechanically robust, cost effective and simple to manufacture. In full system integration, this transition design eliminates the need for expensive microwave cabling and connectors by directly mounting the waveguide to the microwave transceiver PCB. The proof‐of‐concept transition structure presented in this paper is suitable for microwave applications where low cost and low weight are critical, for example, drone‐based radars for remote sensing and space‐born satellites. The fabricated structure is characterised using two sets of waveguide components manufactured with different 3‐D printing technology and metallisation process': conductive spray painted Fused Deposition Modelling—Polylactic Acid (PLA Painted) and copper electroplated Stereolithography (SLA Plated). Scattering parameters for both types are measured in a short and back‐to‐back configuration, obtaining the reflection coefficient and insertion loss. Measurements indicate good agreement with modelling and measured performance exceeding prior art. The measured operation band of the Copper‐SLA version is 2.9–7.2 GHz with <−10 dB reflection coefficient (S11) and with an insertion loss (S21) of <0.7 dB. With the reduced metallisation and surface quality of the Spray‐PLA model, the band is shifted to 3.0–8.0 GHz with an increased S21 of <1.8 dB. The results demonstrate the importance of adopting new transition structures for 3‐D printed microwave components where the surface roughness, metallisation quality, and mechanical properties are less optimal. By combining the proposed design with 3‐D printed metallised microwave components, very light weight and cost‐effective antenna systems can be implemented. Radiation measurements of a 3‐D printed double ridge horn antenna connected to the waveguide and used as a feed are also presented, where the operation band is measured to 3–10 GHz with a gain of 5–10 dBi. [ABSTRACT FROM AUTHOR]

Inspection of defects in the printed circuit boards (PCBs) has both safety and economic significance in the 4.0 industrial manufacturing. Nevertheless, it is still a challenging problem to be studied in-depth due to the complexity of the PCB layouts and the shrinking down tendency of the electronic component size. In this paper, a real-time automated supervision algorithm is proposed to test the PCBs quality among different scenarios. The density of the PCBs layout and the complexity on the surface are analyzed based on deep learning and image feature extraction algorithms. To be more detailed, the ORB feature and the Brute-force matching method are utilized to match perfectly the input images with the PCB templates. After transferring images by aiding the RANSAC algorithm, a hybrid method using modern computer vision algorithms is developed to segment defective areas on the PCBs surface. Then, by applying the enhanced Residual Network-50, the proposed algorithm can classify the groove defects on the surface mount technology electronic components which minimum size up to 1×3 mm. After the training process, the proposed system is capable to categorize various types of overproduced, recycled, and cloned PCBs. The speed of the quality testing operation maintains at a high level with an average precision rate up to 96.29 % in case of good brightness conditions. Finally, the computational experiments demonstrate that the proposed system based on deep learning can obtain superior results and it outperforms several existing works in terms of speed, precision, and robustness. [ABSTRACT FROM AUTHOR]

Despite the higher thermal conductivity and the higher lifetime offered by silver sintering technologies, most packaged GaN devices are attached using solders due to technological difficulties in the sintering process. In this work, a silver sintering process for a packaged GaN power transistor on a printed circuit board (PCB) was successfully developed. Different sintering paste types were examined regarding their suitability for this application. Electrical measurements, shear tests, and metallographic cross sections were used for the evaluation. Numerical analyses were used to study the internal stress distribution in the GaN package after sintering depending on the paste structure. In the final sintering process, a shear strength of 20 MPa for sintering at 15 MPa and 240°C, for 300 s with electrical functional devices could be obtained by using nanoscale sintering paste. The authors contribute this to the high initial stiffness of the silver layer, which is obtained much earlier in the sintering process compared with the stiffness of a microscale silver paste. This high initial stiffness counteracts the semiconductor device deflection from the applied sintering pressure and reduces the stresses inside the semiconductor. [ABSTRACT FROM AUTHOR]

Usually, the printed circuit board industry has to use special subtractive manufacturing methods, if small line and space dimensions down to 50 μm are desired. This drastically raises production effort and costs. In this article, a method is shown as to how the inkjet technology can be used to produce passive RF structures with minimum line and space dimensions of 25 μm. For the first time, this is possible over complete panels of low-cost printed circuit board (PCB) substrates, which have a relatively high surface roughness compared to ceramic or glass carriers. To ensure process reliability, printed lines must also be plated with an additional electroless copper layer to overcome the surface roughness with conductive layers and to lower insertion loss in the two-digit GHz range. Additionally, a surface impedance model is developed, which allows broadband first time right simulations. Finally, additively produced, passive RF filters are compared to their subtractive counterparts to show their benefits regarding production costs and electrical performance up to 80 GHz. [ABSTRACT FROM AUTHOR]

• Multi-functional lanthanide-doped silicate glasses were synthesized by the sol-gel method. • Raman-active vibration modes confirmed the influence of lanthanides in the structural bonding that augments the electrical conductivity of the glasses. • Er3+ doped glass with the highest dielectric constant of 9.21 × 105 at 0.1 Hz demonstrates its potential for cathode plating in batteries. • Sm3+ infused glass evidencing a low dielectric constant could be suggested for microelectronic components in printed circuit boards that necessitate low signal losses. Lanthanide-doped silicate glasses were subjected to structural and temperature-dependent electrical investigations to validate their multi-functionality in the integrated microelectronic industries. Raman-active vibrations around 920 cm−1 and 1330 cm−1 confirmed the silicate and phosphate tetrahedra respectively. The Er3+ doped glass demonstrated the highest dielectric constant of 9.21 × 105, while Sm3+ infused glass exhibited the lowest dielectric constant of 4.37 × 104 at 0.1 Hz and 473 K. The Sm3+ doped glasses are prospective for plating on copper chips in printed circuit boards that necessitate low dielectric constants to minimize propagation delay. The equivalent circuitry fitted for the Nyquist impedance plot of Er3+ doped glass constituted parallel combinations of a resistor and Constant Phase Element (CPE), in series with Warburg diffusion impedance. The CPE approaching a capacitive nature in the Er3+ doped glass could be suggested for cathode plating in batteries, and fabrication of multi-layer dielectric substrates in radio frequency condensers. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, the reliability of the solder joints of a heterogeneous integration of one large chip (10 × 10 mm) and two smaller chips (735 mm) by a fan-out method with a redistribution layer-first substrate fabricated on a 5153510-mm panel is investigated. Emphasis is placed on the thermal cycling test (25°C D 125°C, 50-min cycle) of the heterogeneous integration package on a printed circuit board (PCB). The thermal cycling test results are plotted into a Weibull distribution. The Weibull slope and characteristic life at median rank are presented. At 90% confidence, the true Weibull slope and the true 10% life interval are also provided. A linear acceleration factor is adopted to map the solder joint reliability at the test condition to the solder joint reliability at an operating condition. The failure location and failure mode of the PCB assembly of the heterogeneous integration package are provided and discussed. A nonlinear, time- and temperature-dependent 3-D finite element simulation is performed for the heterogeneous integration PCB assembly and correlated with the thermal cycling test results. [ABSTRACT FROM AUTHOR]

Drawing from psychological contract, job demands-resources, and affective events theories, this paper proposes and tests a research model where employee engagement (ENG) mediates the impact of psychological contract breach (PCB) on task-related pro-environmental behaviors (TPEBs), proactive pro-environmental behaviors (PPEBs), and intent to remain with the organization (IRO). The linkages given above were assessed via structural equation modeling. Based on data obtained from hotel customer-contact employees in three waves and their immediate supervisors in China, the findings reveal that PCB is a stressor eroding employee ENG, TPEBs, PPEBs, and proclivity to remain with the organization. Employees with high ENG display pro-environmental behaviors at high levels and exhibit elevated IRO. These findings implicitly illustrate that employee ENG partly mediates the impact of PCB on TPEBs, PPEBs, and proclivity to remain with the organization. Implications of these findings are discussed, as are the limitations and avenues for future research. [ABSTRACT FROM AUTHOR]

In this investigation, the chip-last, redistribution-layer (RDL)-first, fan-out panel-level packaging (FOPLP) for heterogeneous integration is studied. Emphasis is placed on the materials, process, fabrication, and reliability of a heterogeneous integration of one large chip (10 3 10 mm2) and two small chips (7 3 5 mm2) by an FOPLPmethod on a 20320-mm2 RDL-first substrate fabricated on a 515 3 510 mm2 temporary glass panel. Reliability test such as the drop test of the heterogeneous integration package on a printed circuit board (PCB) is performed, and test results including failure analysis are presented. Some recommendations are also provided. [ABSTRACT FROM AUTHOR]

The printed circuit board assembly (PCBA) tends to become a bottleneck in an assembly line of electronic products. For improvement, many assembly firms have introduced chip shooter machines. This, however, in turn, raises the issue of how to best utilize these machines. To deal with the PCBA problems, swarm intelligence (SI)-based metaheuristics have been increasingly popular due to the use of guided search that can better drive solutions toward optimality. In this study, we have proposed a novel SI-based metaheuristics, termed improved shuffled frog-leaping algorithm (I-SFLA2), to deal with the feeder assignment problem (FAP), and component sequencing problem (CSP) simultaneously for a chip shooter machine. With novel features such as self-adaptive jump, push jump, direct-jump prevention, and self-adaptive variant, the I-SFLA2 can develop smart jumps for frogs to approach and search around elites quickly while avoiding being trapped in local optima. The I-SFLA2 includes the strategy of transitioning from exploration to exploitation by decreasing the number of memeplexes iteratively. Our small-sized experiments showed the I-SFLA2 had a high hit rate to the optimal solution whereas big-sized experiments showed the I-SFLA2 outperformed the basic SFLA (B-SFLA), B-SFLA(2), the improved SFLA (I-SFLA1), as well as the PSO2 proposed in previous studies. The computational times for the I-SFLA2 were found also reasonable for practical usage. Note to Practitioners—Chip shooter machines have been widely used in industry for printed circuit board assembly (PCBA). Approaches such as exact approach, simple heuristics, and metaheuristics have been proposed for PCBA planning. Although with the capability to find the optimal solution, the exact approaches are found to be computationally intractable when used to deal with a problem of a practical size. Although simple heuristics are easy to use, they usually have the difficulty to find the optimal/near-optimal solution. One recent trend is using metaheuristics to solve PCBA problems as they can avoid the computational intractability of exact approaches while improving over simple heuristics to find a better solution. In this study, we propose an improved shuffled frogs leaping algorithm (I-SFLA2), an advanced swarm intelligence (SI)-based metaheuristic to solve the CSP and FAP simultaneously for a chip shooter machine. With new features and smart jumps, the I-SFLA2 is able to find a better solution compared to some previously-proposed methods. [ABSTRACT FROM AUTHOR]

As all-printed digital circuits are in high demand to produce all-printed active devices, providing accurate and synchronized clocks to all of the printed circuits is an indispensible step. To supply the clock signal to a printed digital circuit, a printed ring oscillator has been considered as a practical solution. However, it is difficult to fully print the ring oscillators with a consistent and stable clock signal. To resolve this problem, we employed single walled carbon nanotube network (SWNTn) as active layers of printed thin film transistors (TFTs) to completely print the ring oscillator. In addition, using the extracted electronic properties from the printed SWNTn-TFTs, we designed a simulation model based on AIM-Spice Model 15 for the printed ring oscillator and compared the simulated clock signals with the experimentally measured values of the printed ring oscillator. [ABSTRACT FROM AUTHOR]

Flip-chip interconnects made entirely from copper are promising candidates to overcome the intrinsic limits of solder-based interconnects and match the demand for increased current densities of high-performance microprocessors. To this end, dip-based all-copper interconnects have been demonstrated to be a viable approach to form electrical interconnects by sintering copper nanoparticles between the copper pillar and pad. However, the performance of this technology is limited by residual porosity of the copper joint formed between the pillar and the pad during sintering. Moreover, the applicability of this technology in the printed circuit board industry is constrained by thermomechanical stresses that arise from the sintering. Furthermore, the compatibility of the sintering approach with standard finishing layers used as diffusion-barrier layers to provide wetting and to prevent the oxidation of the pillar and pad surfaces is unknown. In this paper, we pursue the advancement of dip-based all-copper interconnect technology. We demonstrate the robustness of dip-transfer of copper paste for varying withdrawal velocities and typical nonuniformities in copper pillar heights. Moreover, we prove the applicability of this technology with fine pillar diameters and pitches down to 10 and $20~\mu \text{m}$ , respectively. In addition, we demonstrate reduced porosities of the copper joints by applying pressure during the bonding process at 200 °C. This densification leads to interconnects with four times the shear strength and half the electrical resistance compared to interconnects formed without the application of pressure. In addition, the bonding temperature is decreased to 160 °C by applying a novel copper paste formulation, reducing the thermomechanical stress in the assembly caused by the cooling from the sintering temperature. Finally, the compatibility of this technology with EPAG, ENIG, and ENEPIG finishing layers is demonstrated, with resulting shear strength of the interconnects above 70 MPa and electrical resistance comparable to the unfinished samples. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Fly ash/alumina composite membranes were fabricated without any intermediate layers. • This study provided a comprehensive research on the low cost membrane material. • The membranes had a narrow pore size distribution and satisfactory permeability. • The membranes showed great potential for treating oily emulsions and spent tin wastewater. Abstract Ceramic membranes with asymmetric structures play an important role in treating wastewater in the chemical engineering industry. However, the asymmetric structure requires repetitive "coating-drying-sintering" processes to achieve a ceramic membrane with satisfactory separation accuracy, which in turn requires a long fabrication period and has limited the widespread application of such membranes. Herein, a single-step coating preparation for a high-performance asymmetric ceramic membrane using macroporous fly ash supports has been developed using a thermal spraying technique. The novel coating process can not only prevent the penetration phenomenon and avoid the need for intermediate layers, but also significantly lower the fabrication time and cost of the ceramic membranes. Based on theoretical calculations using the Hagen-Poiseuille (H-P) and Darcy equations, the resistance of the supports and fabricated membrane layer accounted for 8.5% and 91.5% of the total resistance, respectively. The resistance distribution indicates a reasonable membrane structure, with the resistance being mainly concentrated on the membrane. This indicates that the supports only provide high bending strength and do not have an adverse effect on the permeability performance. The fly ash/alumina composite membranes (FACMs) fabricated under the optimized conditions had pore diameters of approximately 100 nm and a permeability of approximately 445 L m−2 h−1 bar−1 (at 0.1 MPa). In the treatment of oily emulsions and spent tin wastewater, the FACMs showed good total organic carbon (TOC) retention (above 99%) and a high rejection for stannic acid (above 99.9%) in industrial spent tin wastewater from the printed circuit board industry. The technique of combining low-cost fly ash supports and the optimized membrane structure could significantly decrease the membrane cost and serve as an efficient method for wastewater treatment. [ABSTRACT FROM AUTHOR]

Electronic waste (E-Waste) is consumed at high speed in the world. These residues contain metals that increase their price each year, generating new research on the ability of microorganisms to recover the metals from these wastes. Therefore, this work evaluated the biologic lixiviation of Cu, Ag and Au from printed circuit boards (PCB) of mobile phones by three strains of Aspergillus niger, Candida orthopsilosis, Sphingomonas sp. and their respective consortia, in addition to leaching with citric acid. The microorganisms were cultured in mineral media with 0.5 g of PCB, and the treatments with 1M citric acid were added the same amount of PCB. All treatments were incubated for 35 days at room temperature. The results showed that Sphingomonas sp. MXB8 and the consortium of C. orthopsilosis MXL20 and A. niger MXPE6 can increase their dry biomass by 147% and 126%, respectively, in the presence of PCB. In the bioleaching of metals, the inoculation of A. niger MXPE6, the consortium of Sphingomonas sp. MXB8/C. orthopsilosis MXL20 and Sphingomonas sp. MXB8 leached 54%, 44.2% and 35.8% of Ag. The consortium of A. niger MX5 and A. niger MXPE6 showed a leaching of 0.53% of Au. A. niger MX5 leaching 2.8% Cu. Citric acid increased Cu leaching by 280% compared to treatments inoculated with microorganisms. Although further research is required, A. niger MXPE6 and the consortium of Sphingomonas sp. MXB8/C. orthopsilosis MXL20 could be an alternative to recover Ag from PCB of mobile phones. [ABSTRACT FROM AUTHOR]

In this paper, a method for substrate permittivity and loss tangent characterization applicable for frequencies in the subterahertz range is presented. Planar transmission lines fabricated on three different printed circuit board (PCB) materials and four different on-chip/on-wafer materials are being used for measurement along with a wafer probing station equipped with on-wafer probes and frequency extenders. A comprehensive procedure for calculation of substrate permittivity, total loss, characteristic impedance, and dielectric loss tangent is presented. Measurement data up to 67 GHz is given in case of PCB and up to 500 GHz in case of on-chip/on-wafer materials and compared against reference data and competitive materials from recent publications. [ABSTRACT FROM AUTHOR]

Abstract The crushing is a crucial unit operation for recycling waste printed circuit boards. In this study, dimethylacetamide was used to improve the crushing efficiency of waste printed circuit boards. The sectional morphology of the printed circuit boards was observed by scanning electron microscopy after a swelling treatment, the result showed the metal-nonmetal interface appeared noticeable cracks. The mechanical properties of material was measured by dynamometer, the results indicated that the destructive load of treated printed circuit boards was reduced by 115.32 N. The yield and metal grade of the crushed products were determined for each fraction. For the −0.074 mm fraction, the swelling treatment reduced the yield by 8.19% versus the regular treatment. For the −0.5 + 0.25 mm fraction, the grade of copper was increased by 7.35% after the swelling treatment. In addition, the main trace elements of the electrical components can be enriched in the coarse fraction. An analysis of the infrared spectra of the organic solvent before and after the swelling treatment revealed that the compositions of the organic solvent and the resins remained unchanged with this treatment. The swelling process of printed circuit boards was illustrated by the non-uniform effects of thermal expansion of materials and the interaction of organic solvent with nonmetal. Further, the hydrogen bonds between the dimethylacetamide and the resin molecules were expressed by a molecular structure diagram. Overall, this method can achieve metal liberation and enrichment in the coarse fraction, reducing the generation of fine particles and organic solvent can also be recycled. Thus, this study provides an alternative approach to improve the crushing efficiency of waste printed circuit boards. Graphical abstract Image 10 Highlights • A new way was applied to improve the crushing effect of waste printed circuit boards. • The swelling treatment can better achieve metal liberation and reduce the yield of fine particles. • The effect of thermal expansion promoted the swelling of printed circuit boards. • The interaction of dimethylacetamide with nonmetal contributed to expand. [ABSTRACT FROM AUTHOR]

Abstract The aim of this study is to establish the potential novel approach for the selective synthesis of copper-nickel (CuNi) alloys using two waste streams, printed circuit board (PCB) and nickel-metal hydride (NiMH) batteries. A thermal route is established to synthesise CuNi alloys by using waste PCB, simultaneously as a Cu source and reducing agent from C-bearing polymer and waste NiMH batteries as Ni source. Thermal transformation and reduction studies were carried out at 1500 °C under an inert atmosphere. Initial characterization of raw materials was conducted in detail using various analytical techniques. Synthesised CuNi alloys were confirmed with ICP, EDS and XRD analyses. Material ratios of 75–25 wt% and 50-50 wt% of NiMH battery and PCB waste was considered and these range of compositions of e-waste, as raw materials, minimised the slag generation and optimised Ni recovery. Concentration of Nickel in the synthesised alloys was 20–30 wt%. Reduction extent of nickel oxide using PCB as reductant was confirmed by off-gas analysis. This approach has the potential to be implemented in selective synthesis of CuNi alloys instead of using conventional ores/reductant, to achieve target composition of alloys as per application requirements including marine/automotive/electronic industries. This novel approach promises significant benefits to divert e-wastes from landfill and provide sustainable solution for future metal alloy security. Highlights • Novel and sustainable pathway to synthesise CuNi alloys using e-waste. • Waste PCB as Cu source and as reductant is used to reduce NiO from NiMH battery. • Synthesised CuNi alloys are confirmed by XRD, EDS and ICP analysis. • Ni is homogenously distributed in the alloy and complete recovery of Ni is achieved. • The approach will divert huge volume of e-waste from landfill. [ABSTRACT FROM AUTHOR]

During the manufacturing of printed circuit boards (PCBs) for a Flight Project, it was found that a European manufacturer was building its boards to a European standard that had no requirement for copper wrap on the vias. The amount of copper wrap that was measured on coupons from the panel containing the boards of interest was less than the amount specified in IPC-6012 Rev B, Class 3. To help determine the reliability and usability of the boards, three sets of tests and a simulation were run. The test results, along with results of simulation and destructive physical analysis, are presented in this paper. The first experiment involved subjecting coupons from the panels supplied by the European manufacturer to thermal cycling. After 17 000 cycles, the test was stopped with no failures. A second set of accelerated tests involved comparing the thermal fatigue life of test samples made from FR4 and polyimide with varying amounts of copper wrap. Again, the testing did not reveal any failures. The third test involved using interconnect stress test coupons with through-hole vias and blind vias that were subjected to elevated temperatures to accelerate fatigue failures. While there were failures, as expected, the failures were at barrel cracks. In addition to the experiments, this paper also discusses the results of finite-element analysis using simulation software that was used to model plated-through holes under thermal stress using a steady-state analysis, also showing the main failure mode was barrel cracking. The tests show that although copper wrap was sought as a better alternative to butt joints between barrel plating and copper foil layers, manufacturability remains challenging and attempts to meet the requirements often result in features that reduce the reliability of the boards. Experimental and simulation work discussed in this paper indicate that the standard requirements for copper wrap are not contributing to the overall board reliability, although it should be added that a design with a butt joint is going to be a higher risk than a reduced copper wrap design. The study further shows that procurement requirements for wrap plating thickness from Class 3 to Class 2 would pose little risk to reliability (minimum 5 μm/0.197 mil for all via types). Experimental results corroborated by modeling indicate that the stress maxima are internal to the barrels rather than at the wrap location. In fact, the existence of Cu wrap was determined to have no appreciable effect on reliability. [ABSTRACT FROM AUTHOR]

In this article, a miniaturized resonator based on substrate integrated coaxial line technology (SICL) is presented. The SICL resonator consists of a hairpin half-wavelength open-ended coaxial line element and two symmetrical parallel coaxial feed lines. The gap between the feed lines and the hairpin element can be adjusted properly to obtain a steep phase change, which can result in a higher group delay peak and achieve a superior phase noise performance. Based on the proposed SICL resonator, an X-band oscillator has been designed and demonstrated by using low-cost printed circuit boards (PCBs). Great consistency between the measured and simulated results is verified. According to the measured results, the oscillation frequency of the SICL oscillator is 10.0625 GHz with −1.81 dBm RF output power, and the phase noise is −138.6 dBc/Hz@1 MHz. The statistic figure of merit (FOM) is −206.1 dBc/Hz@1 MHz. [ABSTRACT FROM AUTHOR]

In this communication, a corporate stacked microstrip and substrate integrated waveguide (SIW) feeding structure is reported to be used to broaden the impedance bandwidth of a $4 \times 4$ patch array antenna. The proposed array antenna is based on a multilayer printed circuit board structure containing two dielectric substrates and four copper cladding layers. The radiating elements, which consist of slim rectangular patches with surrounding U-shaped parasitic patches, are located on the top layer. Every four radiation elements are grouped together as a $2 \times 2$ subarray and fed by a microstrip power divider on the next copper layer through metalized blind vias. Four such subarrays are corporate-fed by an SIW feeding network underneath. The design process and analysis of the array antenna are discussed. A prototype of the proposed array antenna is fabricated and measured, showing a good agreement between the simulation and measurement, thus validating the correctness of the design. The measured results indicate that the proposed array antenna exhibits a wide $\vert \text {S}_{11}\vert < -10$ dB bandwidth of 17.7%, i.e., 25.3–30.2 GHz, a peak gain of 16.4 dBi, a high radiation efficiency above 80%, and a good orthogonal polarization discrimination of higher than 30 dB. In addition, the use of low-profile substrate in the SIW feeding network makes this array antenna easier to be integrated directly with millimeter-wave front-end integrated circuits. The demonstrated array antenna can be a good candidate for various Ka-band wireless applications, such as 5G, satellite communications and so on. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Mineralogical characteristics of nonmetallic fraction of WPCBs were analyzed. • Vibrated gas-solid fluidized bed can recycle residual metals from fine WPCBs. • Removing glass fibers can strengthen the gravity segregation process. Abstract Nonmetallic fractions are essential byproducts of the physical-mechanical recycling process of waste printed circuit boards. Large amounts of metals remain in fine nonmetallic fractions because it is very hard for recycling metals from fine size fraction by traditional technologies. In this study, a vibrated gas-solid fluidized bed was utilized to recover residual metals from fine particles (−0.25 mm size) of nonmetallic fractions obtained from the corona electrostatic separation process. The basic mineralogical characteristics and properties of nonmetallic fractions with a size of −0.25 mm indicated that a considerable amount of clavate glass fibers existed in these nonmetallic fractions. The content of residual metals in the −0.25 mm nonmetallic fractions was up to 19.84 wt%. The major metallic elements found in the nonmetallic fractions were Fe, Cu, Pb, and Sn. The results indicated that removing glass fibers from nonmetallic fractions by triboelectric separation can strengthen the gravity-segregation process between heavy and light particles in fine nonmetallic fractions, resulting in improved metal recovery from 76.39% to 81.41%. Based on this research, an industrial flowsheet for the recovery of metals from fine WPCBs is proposed. [ABSTRACT FROM AUTHOR]

This paper presents a 64-element 28-GHz phased-array transceiver for 5G communications based on $2\times 2$ transmit/ receive (TRX) beamformer chips. Sixteen of the $2\times 2$ TRX chips are assembled on a 12-layer printed circuit board (PCB) together with a Wilkinson combiner/divider network and 28–32-GHz stacked-patch antennas. The 64-element array results in 1.1 dB and 8.9° rms amplitude and phase error, respectively, with no calibration due to the symmetric design of the $2\times 2$ beamformer chips and the PCB Wilkinson network. The effect of phase and amplitude mismatch between the 64 elements is analyzed and shown to have little impact on the 64-element array performance due to the averaging effects of phased arrays. Detailed pattern, effective isotropic radiated power (EIRP), and link measurements performed without any array calibration are presented and show the robustness of the symmetrical design technique. The phased array can scan to ±50° in azimuth ($H$ -plane) and ±25° in elevation ($E$ -plane) with low sidelobes and achieves a saturated EIRP of 52 dBm with 4-GHz 3-dB bandwidth. A 300-m wireless link is demonstrated with a record-setting data rate of 8–12 Gb/s over all scan angles using two 64-element TRX arrays and 16-/64-QAM waveforms. [ABSTRACT FROM AUTHOR]

This paper presents the new printed-circuit board (PCB) technology medium voltage combined instrument transformer. The capacitors of the voltage transformer and coils of the current-to-voltage transducers are designed and manufactured using PCB technology. The design of the insulation system of the combined transformer was carried out using electric field analysis. The electric field distributions, computed by applying the 3-D finite-element numerical method, are presented. The results for several different applications were compared with tests of real-life models. [ABSTRACT FROM AUTHOR]

[Display omitted] • A flow-cell-based electrochemical analyzer was developed. • It enabled the fast determination of additive concentrations in a Cu plating bath. • Linear interpolation was used to analyze the concentrations. • The isotherm-based plotting provided better linearity with higher R2 values. Automatic Cu plating bath analyzers are required for the long-term maintenance of the bath quality in the semiconductor and printed circuit board industries. This study reports the development of a flow cell-based electrochemical analyzer for the simple and fast determination of additive concentrations in a Cu plating bath. To determine the additive concentrations, cyclic voltammetry was sequentially performed using a flow cell system for the following solutions: blank, blank + sample, and two references. The stripping charges for each solution were obtained. The concentrations of the additives in the target solution were determined by the linear interpolation of the stripping charge between the two references. To improve the determination accuracy, the stripping charges were reprocessed based on adsorption isotherms. The proposed approach enables the fast and highly accurate determination of organic additives in a Cu electroplating solution. [ABSTRACT FROM AUTHOR]

The aim of the study was to recover copper and lead metal from waste printed circuit boards (PCBs). The electrowinning method is found to be an effective recycling process to recover copper and lead metal from printed circuit board wastes. In order to simplify the process with affordable equipment, a simple ammonical leaching operation method was adopted. The selected PCBs were incinerated into fine ash powder at 500°C for 1 hour in the pyrolysis reactor. Then, the fine ash powder was subjected to acid-leaching process to recover the metals with varying conditions like acid-base concentration, electrode combination, and leaching time. The relative electrolysis solution of 0.1 M lead nitrate for lead and 0.1 M copper sulphate for copper was used to extract metals from PCBs at room temperature. The amount of lead and copper extracted from the process was determined by an atomic absorption spectrophotometer, and results found were 73.29% and 82.17%, respectively. Further, the optimum conditions for the recovery of metals were determined by using RSM software. The results showed that the percentage of lead and copper recovery were 78.25% and 89.1% should be 4 hrs 10 A/dm2. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The influence of waste PCBs characteristics on flotation was examined. • The nonmetal SE was calculated and the particles interaction was studied by EDLVO. • The agglomeration of nonmetal was solved by regulation surface energy using tannin. • The mechanism of pharmacy dispersion and adsorption were expound. • The flotation efficiency of PCBs was enhanced by improving nonmetal dispersion. Abstract This paper studied the influence of waste printed circuit boards (PCBs) characteristics and nonmetal surface energy (SE) regulation on flotation. First, SEM-EDS was applied to study the appearance and surface element distribution of the glass fiber and copper. The results showed that the glass fiber was present in a bundle and the surface carbon content was 49.42%, which facilitated glass fiber floating. The copper appearance contained many nodules, with a carbon content of 32.54%, which hindered copper sorting. XPS analysis further discovered that copper was mainly present in the forms of CuO, Cu(Met), and Al 2 Cu. A FT-IR analysis revealed that the organic matter in the PCBs was essentially the same as the epoxy resin. It was easy to achieve floating and some polar functional groups promoted the adsorption of the flotation reagents. Based on this, by calculating the nonmetal SE, it was found that the proportion of the non-polar component of the nonmetal SE was 94.60%. The EDLVO theory was applied to research interactions between nonmetal particles. Hydrophobic attraction was found to be the main factor causing nonmetal particles to agglomerate. Further, the tannin was used to improve the dispersion of nonmetal by adjusting the nonmetal SE. Furthermore, the hydroxyl and carbonyl groups in the tannin may form hydrogen bonds with the bromine, epoxy and hydroxyl groups in the nonmetal. Finally, flotation test results indicated that tannin added significantly enhanced PCBs flotation efficiency. When the amount of tannin added increased from 0 to 60 mg/L, the recovery of copper increased from 61.92% to 90.53%. Thus, this study provides an alternative approach to improve the flotation efficiency of waste PCBs. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • An effective process was proposed for decomposition and debromination of PCBs. • Effect of temperature on pyrolysis products was studied. • High production of phenol was obtained by the zero-valent metals. • Excellent debromination performance was achieved by Fe metals. Abstract The non-metallic fraction of waste printed circuit boards (PCBs) has received extensive attention for material recycling, due to the potential risk of brominated flame retardants and heavy metals in PCBs. Here, the catalytic pyrolysis of PCBs was performed at 400–600 °C in a two-stage fixed bed reactor. Low-cost Fe and Ni metals were investigated for their catalytic effect on the product yields and bromine removal from the pyrolysis products. In the absence of additives, the maximum oil yield of 50.1 wt% was obtained at 500 °C from the PCBs pyrolysis. The addition of Ni particles decreased the oil yield to 29.1 wt%, and increased the gas yield to 9.6 wt% at 600 °C. The Fe/Ni mixture had a synergistic effect on the product yields, which depended on different pyrolysis temperatures. The composition of the oils from the PCBs pyrolysis was dominated by phenol derivatives. The presence of Fe or Ni particles promoted the formation of phenol and other aromatic compounds, such as benzene and toluene. Moreover, the transformation of bromine species was exhaustively investigated. The higher temperature promoted the conversion of brominated compounds into HBr. Fe particles exhibited excellent debromination performance, which not only reduced the formation of organobromine compounds, but also captured some of the evolved bromine. [ABSTRACT FROM AUTHOR]

Background: In this study, a machine vision-based method was developed for automated in-process light-emitting diode chip mounting lines with position uncertainty. In order to place the tiny light-emitting diode chips on the pattern of a printed circuit board, a highly accurate mounting process is achieved with online feedback of the visual assistance. Methods: The system consists of a charge-coupled device camera, a six-axis robot arm, and a delta robot. The lighting system is a critical point for the in-process machine vision problem. Hence, designing the optimal lighting solution is one of the most difficult parts of a machine vision system, and several lighting techniques and experiments are examined in this study. In order to commence the mounting process, the light-emitting diode chip targets inside the camera field were identified and used to guide the delta robot to the grabbing zone based on the calibrated homography transformation. Efforts have been focused on the field of machine vision-based feature extraction of the chip pins and the holes on the printed circuit board. The correspondence of each other is determined by the position of the chip pins and the printed circuit board circuit pattern. The image acquisition is achieved directly online in real time. The image analysis algorithm must be sufficiently fast to follow the production rate. In order to compensate for the uncertainty of the light-emitting diode chip mounting process, a visual feedback strategy in conjunction with an uncertainty compensation strategy is employed. Results: Finally, the light-emitting diode chip was automatically grabbed and accurately placed at the desired positions. Conclusion: On-line and off-line experiments were conducted to investigate the performance of the vision system with respect to detecting and mounting light-emitting diode chips. [ABSTRACT FROM AUTHOR]

This study presents a novel design of a wideband high-gain resonant cavity antenna (RCA) for millimetre and submillimetre wave bands, and its fabrication using additive manufacturing (AM). The proposed RCA antenna consists of a partially reflecting surface and three impedance matching layers fed by a waveguide. AM techniques are utilised to fabricate the design operating at 30 GHz. Two fabrication techniques are assessed for printing the antenna. The first technique is based on printing a dielectric material and fully coating the parts with a metallic layer, while the second technique involves printing the parts in a single process using metal three-dimensional printing. The first technique offers a lightweight solution while the second technique can print the whole model in one run. The antenna design is investigated by both simulations and experiments. The measured results show a 3 dB gain bandwidth of about 10%, and high gain over 15 dBi for all the three resulting antennas. Good agreement between simulation and measurement is obtained. The antenna is of low cost and achieved good performance in terms of wide bandwidth and high gain, thus it is potentially useful for high-speed wireless communications at millimetre-wave and sub-millimetre-wave frequencies. [ABSTRACT FROM AUTHOR]

The radiation performance of the resonant cavity antenna (RCA) is mainly determined by the superstrate, and thereby various superstrates are designed for the RCA to obtain high performance. In this work, the comparative effects of the capacitive and inductive superstrates on the RCA's gain are investigated systematically. Three approaches including the leakywave model, full-wave simulations and prototype measurements are employed for the investigation. Using the leaky-wave model, the gains of the RCA with various superstrates are calculated and a difference between the gains with the capacitive and inductive superstrates is observed. Full-wave simulations and prototype measurements further prove the result. All the approaches demonstrate that the capacitive superstrate has the potential to obtain a higher gain, in comparison with the inductive superstrate having the same reflection magnitude and aperture size. [ABSTRACT FROM AUTHOR]

The fatigue damage that accumulates on a solder joint under a launch vibration environment is a major cause of failure in spaceborne electronics. Thus, predicting the mechanical safety of the solder joint in the structural design phase is important to guarantee a successful space mission. This paper proposes a mechanical design methodology to predict and ensure more reliable mechanical safety of the solder joints of a plastic ball grid array (PBGA) and a thin-shrink small outline package (TSSOP) under launch random vibration excitation. Random vibration fatigue tests for a sample printed circuit board (PCB) assembly were performed to assess the fatigue life of BGA and TSSOP solder joints. The effectiveness of the proposed structural design methodologies was evaluated by comparing the margin of safety calculated from various analysis approaches and the random vibration fatigue test results of the PCB specimen. [ABSTRACT FROM AUTHOR]

This paper is dedicated to the characterization of internal charging and discharging processes of different systems or materials in medium earth orbit (MEO) environment. Experiments for MEO were carried out at the ONERA, Toulouse, France, using the Geostationary Dielectric Unit Radiation electron beam facilities. Assuming 2.5 mm of Al shielding on the spacecraft, a worst case electron spectrum emerging from the shielding has been calculated from previous works. Different materials or systems have been tested in this configuration: printed circuit board (PCB) and insulating materials used for cables or connectors [polyetheretherketone, ethylene tetrafluoroethylene (ETFE), and Kapton]. The experiments revealed that PCB or ETFE cables might be prone to present a high risk of charging and discharging after several days under extreme environment. Electrostatic discharges have then been detected on PCBs. An experimental and numerical method has also been defined and validated at ONERA to assess the charging levels in long-term space environment through short-duration experiments performed at higher electron current. This method requires the extraction of electric parameters (especially radiation-induced conductivity) of the tested materials. From these parameters, it was demonstrated that the extrapolation of the experimental results was feasible for most space used materials. [ABSTRACT FROM AUTHOR]

A codesign of an electrostatic discharge (ESD) protection device and a common-mode suppression circuit on printed circuit board (PCB) for high-speed input/output interfaces is introduced in this paper. The characteristic and the circuit model of the ESD protection device are investigated and applied into the design of the common-mode suppression circuit. The proposed one-stage design of two-layered PCB structure performs -10-dB common-mode noise suppression from 2.22 to 2.76 GHz; the proposed two-stage design with additional common-mode suppression unit performs wideband suppression from 2.25 GHz to over 8 GHz, covering IEEE 802.11acWiFi band with -20-dB suppression level. The mode conversion for both designs is lower than -30 dB. The signal integrity and the ESD protection function of proposed design are investigated by eye diagram measurement and system-level ESD simulation. The proposed PCB design provides a low-cost solution for the integration on the high-speed input/output interface of next generation. [ABSTRACT FROM AUTHOR]

In this study, using several types of acidic ionic liquids as the leaching reagents, the leaching behaviors of the copper present in waste printed circuit boards (WPCBs) were investigated. The effects of various parameters on the copper leaching rate were studied, such as the particle size of the shredded WPCB, type of ionic liquid used, hydrogen peroxide dosage, solid-to-liquid ratio, leaching temperature, and leaching time. The experimental results showed that the copper leaching rate increases continuously when the powder particle size is increased from 0.071 to 0.500 mm. Moreover, the copper leaching rate also increases with an increase in the leaching temperature. In contrast, the leaching rate first increases and then decreases with increases in the leaching time, hydrogen peroxide dosage, and solid-to-liquid ratio. The optimal conditions that provided a 98.31% copper leaching rate were: particle size >0.500 mm, 8.5 mL 90% (v/v) ionic liquid, 1.5 mL 30% hydrogen peroxide, solid-to-liquid ratio of 1/20, leaching temperature of 80 °C, and leaching time of 2 h. [ABSTRACT FROM AUTHOR]

To establish an effective recycling process for waste appliances, the process of recovering printed circuit boards (PCBs) containing valuable elements in comminution was investigated and evaluated. The present study performed comminution tests using three different types of waste appliances: smartphones, microwave ovens and electrical rice cookers. Comminution tests showed that a drum-type agitation mill operated at a mid-range rotation speed could achieve a relatively high recovery ratio of PCBs and inhibit excessive breakage of PCBs. Following these experiments, simulations using the discrete element method with a particle-based rigid-body model were conducted to evaluate the comminution performance of the drum-type agitation mill. Experimental and simulation results confirm that the processes of detachment of PCBs from waste appliances and subsequent breakage can be expressed by kinetic equations related to collision energy. It is concluded from these results that the kinetic equations obtained in experiments and simulations can be used to evaluate the recovery process of PCBs from waste appliances. [ABSTRACT FROM AUTHOR]

Electronic waste (e-waste) is generated at a rapid pace due to technological advancement and thereby reduced obsolescence age of electrical and electronic equipment (EEE). E-waste comprises of many useful recyclable materials such as metallic fractions (MFs), like aluminum and copper and non-metallic fractions (NMFs), such as plastic, printed circuit boards (PCB) and glass. Classification of MFs and NMFs from e-waste is of great significance from the viewpoint of recycling of materials and resource recovery. In this paper, we focus on the classification of MFs and NMFs from e-waste using thermal imaging-based technique operated in the long-wave infrared range (LWIR) 8-15 μm. We use a feature vector comprising of mean intensity, standard deviation and the image-sharpness extracted from the thermograms of individual materials present in e-waste. We developed a classification model to classify the feature vectors into broad categories of metal, PCB, plastic, and glass. We conducted several experiments on simulated e-waste to validate the developed approach and obtained a classification success rate in the range of 84-96%. We believe that the proposed approach is a viable solution for multi-material classification of e-waste into broad categories and can be scaled up to fit for an e-waste recycling plant. [ABSTRACT FROM AUTHOR]

Copper nitride particles have a low decomposition temperature, they absorb light, and are oxidation-resistant, making them potentially useful for the development of novel wiring inks for printing circuit boards by means of intense pulsed light (IPL) sintering at low-energy. Here, we compared the thermal decomposition and light absorption of copper materials, including copper nitride (Cu3N), copper(I) oxide (Cu2O), or copper(II) oxide (CuO). Among the copper compounds examined, copper nitride had the second highest light absorbency and lowest decomposition temperature; therefore, we concluded that copper nitride was the most suitable material for producing a wiring ink that is sintered by means of IPL irradiation. Wiring inks containing copper nitride were compared with those of wiring inks containing copper nitride, copper(I) oxide, or copper(II) oxide, and copper conversion rate and sheet resistance were also determined. Under low-energy irradiation (8.3 J cm-2), copper nitride was converted to copper at the highest rate among the copper materials, and provided a sheet resistance of 0.506 Ω sq-1, indicating that copper nitride is indeed a candidate material for development as a wiring ink for low-energy intense pulsed light sintering-based printed circuit board production processes. [ABSTRACT FROM AUTHOR]

The corrosion inhibitor of nitrogen-containing amino acid histidine (His) has been applied in brown oxidation solutions and the relationships between brown oxidation solutions with the various concentrations of His and the adhesion strength of copper/resin laminates have been systematically studied by various testing techniques, including electrochemical impedance spectroscopy (EIS), peeling strength and field emission scanning electronic microscope. The result obtained from EIS suggested that His exhibited excellent anti-corrosive performance which contributed to a higher stability of the organic metallic film post brown oxidation process treatment. The roughness surface like honeycomb structure was gained and peel strength of the Cu/resin laminates was raised up to 0.71 kg/cm by altering the concentration of His in brown oxidation solutions. Moreover, theoretical calculations manifested that the studied inhibitor was almost adsorbed in parallel on the copper surface and X-ray photoelectron spectroscopy (XPS) declared that the value of adhesion strength was related to the surface chemistry of copper foil and resins after the lamination process which may attribute to chemical reactions at the copper/resin interface. [ABSTRACT FROM AUTHOR]

This paper describes the design and implementation of a W-band phased-array system with printed circuit board (PCB) integrated antennas in two polarizations capable of multi-gigabit spectrally efficient wireless communication. The chipset is manufactured in a 0.18- $\mu \text{m}$ SiGe BiCMOS technology with $f_{T}/f_{\mathrm {MAX}}$ of 240-/270-GHz and is flip-chipped onto a low-cost organic PCB with integrated antenna arrays. Each chip is equipped with 16-transmit/4-receive or 16-receive/4-transmit calibrated phase shifter elements and direct up- and downconverters plus a half-rate phase-locked loop. The different system tradeoffs required to establish a multi-Gb/s wireless link at millimeter waves are carefully studied. Built-in element failure detectors, power detectors, and digital interface enable factory calibration and self-test capability. Each transceiver chip operates from 1.5- and 2.5-V supplies and consumes 5.5 and 4.5 W in transmit and receive mode, respectively. The peak transmitter effective isotropic radiation power is 34 dBm in each polarization with a measured receiver noise figure of 6.5 dB at 94 GHz. At a distance of 1 m, a maximum wireless data rate of 30 Gb/s (per polarization) using 64-QAM can be achieved and at 20 m, 8 Gb/s (dual polarization) can be established using QPSK modulation. [ABSTRACT FROM AUTHOR]