Search results

The purpose of this paper is to introduce a new copper electroplating formula which is able to fill blind microvias (BVHs) and through holes (THs) at one process through a direct current (DC) plating method.

Test boards of printed circuit board (PCB) fragments with BVHs and THs for filling plating are designed. The filling plating is conducted in a DC plating device, and the filling processes and influence factors on filling effect of BVHs and THs are investigated. Dimple depths, surface copper thickness, thermal shock and thermal cycle test are applied to characterize filling effect and reliability. In addition, to overcome thickness, increase of copper on board surface during filling plating of BVHs and THs, a simple process called pattern plating, is put forwarded; a four-layered PCB with surface copper thickness less than 12 μm is successfully produced.

The filling plating with the new copper electroplating formula is potential to replace the conventional filling process of BVHs and THs of PCB and, most importantly, the problem of thickness increase of copper on board surface after filling process is overcome if a pattern plating process is applied.

The dimple depth of BVHs and THs after filling plating is not small enough, though it meets the requirements, and the smallest diameter and largest depth of holes studied are 75 and 200 μm, respectively. Hence, the possibility for filling holes of much more small in diameter and large in depth with the plating formula should be further studied.

The paper introduces a new copper electroplating formula which achieves BVHs and THs filling at one process through a DC plating method. It overall reduces production processes and improved reliability of products resulting in production cost saving and production efficiency improvement.

Taking Tibet as a case study, this paper aims to develop an in-depth understanding of the influence that off-season tourism promotion (OTP) has on seasonal destinations from a multi-stakeholder perspective.

A qualitative research method was designed using participatory observation, in-depth interviews and focus group interviews in Tibet from March 2018 to February 2019.

The results revealed the different effects of OTP on destinations from a multi-stakeholder perspective. Residents report place change as a perceived threat from off-season tourists. Additionally, the irregular nature of seasonal employment can lead to service provider–related failures. While traditional seasonal tourists viewed OTP promotions as the destruction of place identity, promotion-motivated tourists presented a lesser degree of place loyalty. The prospect of off-season tourism has also led to concerns among scholars regarding deteriorating environmental sustainability.

This paper can help destination managers and policymakers re-assess the effects of seasonality and off-season tourism policies.

This paper discusses the phenomenon of seasonality from a multi-stakeholder perspective. The study explores residents’ perception of OTP-related place change, the causes of seasonal employment and how the market segments in off-season tourism, all of which complement existing research. Lastly, using a mixed data collection and analysis method, the study provides a feasible approach to analyze tourism phenomena.

标题:淡季旅游促销如何影响季节性目的地?多元利益相关者视角下的西藏

本(límite de 100 palabras)文以西藏为例, 从多方利益相关者的角度深入了解了旅游淡季促销（OTP）对季节性旅游目的地的影响。

本文采用参与式观察法、深度访谈法、焦点小组访谈法, 于2018年3月至2019年2月在西藏开展定性研究。

研究结果从多方利益相关者的角度揭示了旅游淡季促销（OTP）对目的地的不同影响。根据居民的报告, 地方的变化被视为来自淡季游客的威胁。此外, 季节性就业的不规律性可能导致服务提供方出现相关问题。传统的季节性游客认为OTP是对地方认同的破坏, 而以促销为动机的游客对地方的忠诚度较低。淡季旅游的前景也引起了学者们对环境可持续性恶化的担忧。

本文可以帮助旅游地管理者和决策者重新评估季节性和淡季旅游政策的影响。

本文从多方利益相关者的角度探讨了季节性现象。本研究探讨了居民对OTP相关的地点变化的感知、季节性就业的原因以及淡季旅游的市场细分, 这些都弥补了现有研究的不足。最后, 运用混合数据收集与分析方法, 为旅游现象的分析提供了一条可行的途径。

季节性, 淡季旅游, 定性, 利益相关者, 可持续性, 西藏

Cómo la promoción del turismo fuera de temporada afecta los destinos estacionales？ Una perspectiva de múltiples actores en el Tíbet

Tomando el Tíbet como un estudio de caso, este documento desarrolla una comprensión profunda de la influencia que la promoción turística fuera de temporada (OTP) tiene en los destinos estacionales desde una perspectiva de múltiples actores.

Se diseñó un método de investigación cualitativa utilizando observación participativa, entrevistas en profundidad y entrevistas de grupos focales en el Tíbet desde marzo de 2018 hasta febrero de 2019.

Los resultados revelaron los diferentes efectos de OTP en los destinos desde una perspectiva de múltiples actores. Desde el punto de vista de los residentes los cambios en el destino se percibe como una amenaza de los turistas fuera de temporada. Además, la naturaleza irregular del empleo estacional puede conducir a fallos relacionados con los proveedores de los servicios. Mientras que los turistas tradicionales de temporada vieron en las promociones de OTP una pérdida de identidad del lugar, los turistas motivados por la promoción presentaron un menor grado de lealtad al lugar. La perspectiva del turismo fuera de temporada también ha generado preocupaciones entre los académicos sobre el deterioro de la sostenibilidad ambiental.

Este documento puede ayudar a los gerentes de destino y a los responsables políticos a reevaluar los efectos de la estacionalidad y las políticas de turismo fuera de temporada.

Este artículo discute el fenómeno de la estacionalidad desde una perspectiva de múltiples actores. El estudio explora la percepción de los residentes sobre los cambios del destino relacionado con la OTP, las causas del empleo estacional y la percepción que tienen los segmentos de mercado en el turismo fuera de temporada, todo lo cual complementa la investigación existente. Por último, utilizando un método mixto de recopilación y análisis de datos, el estudio proporciona un enfoque factible para analizar los fenómenos turísticos.

estacionalidad, turismo fuera de temporada, cualitativo, partes interesadas, sostenibilidad, Tíbet

Trabajo de investigacion

This paper aims to propose a modified full-additive method (MFAM) to fabricate fine copper lines for high density interconnection (HDI) printed circuit boards (PCBs). In addition, the surface of the fine copper lines is treated with a brown oxidation process to obtain good adhesion between the copper and the dielectric resin.

Fine copper lines fabricated by MFAM were observed to evaluate the undercut quality, in comparison to undercut quality of copper lines fabricated by the semi-additive method and the subtractive method. The effect of the thickness of the dry film on the quality of the copper plating was investigated to obtain the regular shape of fine lines. The fine copper lines treated with the brown oxidation process were also examined to generate a coarse surface microstructure to improve the adhesion between the copper and the dielectric resin. The cross section and surface of as-fabricated fine copper lines were characterized using an optical microscope, a scanning electron microscope and an atomic force microscope.

MFAM has the potential to fabricate high-performance fine copper lines for HDI PCBs. Undercut of as-fabricated fine copper lines could be prevented to meet the design requirement of impedance. In addition, fine copper lines exhibit enough adhesive force to laminate with dielectric resin after the brown oxidation process.

MFAM, with the advantages of high efficiency and being a facile process, is developed to fabricate high-quality fine copper lines for industrial HDI PCB manufacture.

The purpose of this paper is to establish an accurate model to quantify the effect of conductor roughness on insertion loss (IL) and provide improved measurements and suggestions for manufacturing good conductive copper lines of printed circuit board.

To practically investigates the modified model of conductor roughness, three different kinds of alternate oxidation treatments were used to provide transmission lines with different roughness. The IL results were measured by a vector net analyzer for comparisons with the modified model results.

An accurate model, with only a 1.8% deviation on average from the measured values, is established. Compared with other models, the modified model is more reliable in industrial manufacturing.

This paper introduces the influence of tiny roughness structures on IL. Besides, this paper discusses the effect of current distribution on IL.

Eddy currents are inevitable in magnetic resonance imaging (MRI) systems. These currents are mainly induced by gradient fields. This study aims to propose a fast analytical method to calculate eddy currents induced by frequently switching gradient fields in a traditional C-shape MRI system.

Fourier decomposition and magnetic vector potentials were used to calculate the eddy currents. Calculations with the proposed analytical method revealed the spatial distribution and temporal evolution of eddy currents.

Calculation and Maxwell simulation results were consistent. The agreement between calculation and simulation results indicates that increasingly sophisticated structures could be developed. The calculated results could guide the design of improved gradient coils.

Eddy currents induced by gradient current are decomposed into currents induced by each time-harmonic component, and then adding them together to obtain complete contribution of the eddy current. The analytical method was used to characterize the properties of symmetric and asymmetric eddy currents induced by gradient coils in MRI systems. The analytical method can be used to improve the gradient shield during the design of the gradient coil in the MRI system.

A silver‐palladium thick film conductor for aluminum nitride (AlN) substrate has been developed. This conductor film on AlN ceramics had low sheet resistivity, high adhesion strength and good wettability with Pb‐Sn solder. The frit powder of lead borosilicate glass was used as inorganic binders to enhance the adhesion between the conductor and ceramics. After sintering the conductor film connected with the AlN substrate through frit bonding, no transition phases but a multilayer structure is present in the interface. The softening point of the glass was important to the adhesion strength of conductor film. In order to achieve good adhesion, it is necessary that the glass has a proper softening point (about 500‐650°C).

The purpose of this paper is to draw on social exchange theory and heuristic–systematic model to examine how peer-to-peer (P2P) lending firms can enhance their customer acquisition by achieving mobile social media popularity.

Content data collected from multiple sources (websites and mobile applications) were employed to validate the research model.

The mobile social media popularity of P2P lending firms positively influences their customer acquisition. Furthermore, the heuristic cues (i.e. source credibility and content freshness) and the systematic cue (i.e. transaction relevance) potentially affect the firms’ mobile social media popularity.

Mobile social media is not only a platform for firms’ image-building but a critical means of acquiring actual customers. The appropriate use of heuristic–systematic cues in a mobile interface is useful for firms to achieve high user popularity despite the challenges derived from the mobile context.

To achieve higher user popularity in the competitive online world, firms should dedicate greater effort in determining the adequate heuristic–systematic cues designed for the interface of their mobile social media account. The effect of popularity can then help the firms acquire more customers.

This study extends the understanding of social exchange in the context of mobile social media accounts and enriches the knowledge on business value of mobile social media popularity. This paper also contributes to the literature by relating heuristic–systematic cues to firms’ mobile social media popularity.

Based on the conservation of resource theory, this paper explores the impact of differentiated transformational leadership on employees' taking charge in the context of Chinese organizations, with psychological availability as a mediator and collectivism orientation as a moderator.

The authors distributed paired questionnaires to 67 team managers and 219 team members to obtain research data and established a hierarchical linear model for the hypothesis testing.

The results show that team-focus transformational leadership has a significant positive impact on employees' taking charge, and individual-focus transformational leadership has a significant negative impact on employees' taking charge. Specifically, psychological availability plays a partial mediating role between differentiated transformational leadership and employees' taking charge. Moreover, collectivism orientation has no significant moderating effect between team-focus transformational leadership and psychological availability. But it has a significant moderating effect between individual-focus transformational leadership and psychological availability, i.e. the higher the level of collectivism orientation, the stronger the negative effect of individual-focus transformational leadership on psychological availability.

The paper notes the hierarchy of differentiated transformational leadership and divides it into team-focus transformational leadership and individual-focus transformational leadership. It also provides a new mechanism and boundary condition, i.e. differentiated transformational leadership has an impact on employees' taking charge through psychological availability and collectivism orientation is a moderator.

The behavioral decision-making of digital-self is one of the important research contents of the network of crowd intelligence. The factors and mechanisms that affect decision-making have attracted the attention of many researchers. Among the factors that influence decision-making, the mind of digital-self plays an important role. Exploring the influence mechanism of digital-selfs’ mind on decision-making is helpful to understand the behaviors of the crowd intelligence network and improve the transaction efficiency in the network of CrowdIntell.

In this paper, the authors use behavioral pattern perception layer, multi-aspect perception layer and memory network enhancement layer to adaptively explore the mind of a digital-self and generate the mental representation of a digital-self from three aspects including external behavior, multi-aspect factors of the mind and memory units. The authors use the mental representations to assist behavioral decision-making.

The evaluation in real-world open data sets shows that the proposed method can model the mind and verify the influence of the mind on the behavioral decisions, and its performance is better than the universal baseline methods for modeling user interest.

In general, the authors use the behaviors of the digital-self to mine and explore its mind, which is used to assist the digital-self to make decisions and promote the transaction in the network of CrowdIntell. This work is one of the early attempts, which uses neural networks to model the mental representation of digital-self.

The purpose of this paper is to study an electrolytic etching method to prepare fine lines on printed circuit board (PCB). And the influence of organics on the side corrosion protection of PCB fine lines during electrolytic etching is studied in detail.

In this paper, the etching factor of PCB fine lines produced by new method and the traditional method was analyzed by the metallographic microscope. In addition, field emission scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to study the inhibition of undercut of the four organometallic corrosion inhibitors with 2,5-dimercapto-1,3,4-thiadiazole, benzotriazole, l-phenylalanine and l-tryptophan in the electrolytic etching process.

The SEM results show that corrosion inhibitors can greatly inhibit undercut of PCB fine lines during electrolytic etching process. XPS results indicate that N and S atoms on corrosion inhibitors can form covalent bonds with copper during electrolytic etching process, which can be adsorbed on sidewall of PCB fine lines to form a dense protective film, thereby inhibiting undercut of PCB fine lines. Quantum chemical calculations show that four corrosion inhibitor molecules tend to be parallel to copper surface and adsorb on copper surface in an optimal form. COMSOL Multiphysics simulation revealed that there is a significant difference in the amount of corrosion inhibitor adsorbed on sidewall of the fine line and the etching area.

As a clean production technology, electrolytic etching method has a good development indicator for the production of high-quality fine lines in PCB industry in the future. And it is of great significance in saving resources and reducing environmental pollution.