Search results

This study aims to investigate the effects of mass energy and line mass on the geometrical dimensions, microstructures, hardness and mechanical properties of direct laser fabrication parts.

Direct laser fabrication is successfully used to manufacture a series of samples of AISI 316L stainless steel.

The width and height of the deposition layers increase with increasing mass energy and line mass. When the powder feed rate is 0.295 g/s, higher mass energy and line mass create more refined grains. However, mass energy and line mass have adverse effects on grain size at the powder feed rate of 0.241 or 0.187 g/s. Higher ultimate tensile strength (UTS) values and reduced ductility values are obtained in comparison with those obtained by traditional methods. Thus, the increase in the mass energy and line mass improves the mechanical properties of the parts.

This study is helpful for the optimization of the parameters in the direct laser fabrication process.

Bellows-type fluid viscous damper can be used to isolate micro vibration in high-precision satellites. The conventional model cannot describe hydraulic stiffness in the medium- and high-frequency domain of this damper. A simplified analytical model needs to be established to analyze hydraulic stiffness of the damping element in this damper.

In this paper, a bellows-type fluid viscous damper is researched, and a simplified model of the damping element in this damper is proposed. Based on this model, the hydraulic stiffness and damping of this damper in the medium- and high-frequency domains are studied, and a comparison is made between the analytical model and a finite element model to verify the analytical model.

The results show that when silicone oil has low viscosity, a model that considers the influence of the initial segment of the damping orifice is more reasonable. In the low-frequency domain, hydraulic stiffness increases quickly with frequency and remains stable when the frequency increases to a certain value; the stable stiffness can reach 106 N/m, which is much higher than the main stiffness. Excessive dynamic stiffness in the high-frequency domain will cause poor vibration isolation performance. Adding compensation bellows to the end of the original isolator may be an effective solution.

A model of the isolator containing the compensation bellows can be derived based on this analytical model. This research can also be used for dynamic modeling and vibration isolation performance analysis of a vibration isolation platform based on this bellows-type fluid viscous damper.

This paper proposed a simplified model of damping element in bellows-type fluid viscous damper, which can be used to analyze hydraulic stiffness in this damper and it was found that this damper showed stable hydraulic stiffness in the medium- and high-frequency domains.

Competitiveness of pharmaceutical companies hugely depends on new knowledge because of ever-changing technologies and forefront of knowledge. Leadership styles appear to influence knowledge management behavior, but there has been little empirical research on employees' knowledge creation behavior as an outcome of leadership. The study examines how task-oriented leadership affects subordinates' knowledge creation behavior. Based on organismic integration theory (OIT), the study proposes that perception of competitive climate and achievement motivation can conduct as mediators.

Data were collected from 877 full-time working employees in five pharmaceutical companies in China. Participants answered demographic questions and completed the task-oriented leadership, perception of competitive climate, achievement motivation, as well as knowledge creation behavior scale. Structural equation modeling was used to test the hypothesized relationships.

The results review that task-oriented leadership will significantly promote subordinates' knowledge creation behavior. Perception of competitive climate and achievement motivation play mediator roles between task-oriented leadership and subordinates knowledge creation behavior. Perception of competitive climate and achievement motivation have a serial mediating effect between task-oriented leadership and subordinates knowledge creation behavior.

By adopting a task-oriented leadership style through training and development, leaders may stimulate employees more knowledge creation behaviors by transmitting the organization's vision, clarifying their work tasks and setting relatively high-performance standards. Then, organizations should establish a competition mechanism to promote competition among employees, while also preventing malicious competition. Finally, organizations should arouse employees' achievement motivation to stimulate their internal pursuit of success and needs.

Because of the improvement of information technology and the acceleration of knowledge dissemination, the need for new knowledge is becoming more and more urgent in organizations. Knowledge, as a resource that needs to be managed in an organizational environment, has regained researchers' attention. However, a flourishing number of studies explain the organizational knowledge management from the macro level, there is a need to explore how leaders influence their subordinates to create knowledge. From the perspective of extrinsic motivation internalization, this study’s findings contribute to the literature on task-oriented leadership and knowledge creation behavior and expand our understanding of why task-oriented leadership promotes subordinates' knowledge creation behavior.

With the continuous improvement of social and economic development as well as the rising level of demand for spiritual life, the design of cultural and creative products has ushered in new opportunities and challenges. Therefore the research related to cultural and creative products design is an inevitable choice for industrial innovation and market competition. The article aims to analyze the frontier hotspots and trend evolution of theoretical research on cultural and creative design in China by presenting different research fields, personnel and institutions embodied by cultural and creative products, thus providing a forward-looking development reference for China's special cultural and creative product design practice.

In this paper, the visualized citation analysis tool — CiteSpace V is used to analyze and map the relevant literature of Chinese cultural and creative design in CNKI (Chinese National Knowledge Infrastructure) as the data sources, through bibliometric methods, in order to study the application development of Chinese cultural and creative design and provide reference for the application research of Chinese cultural and creative industries.

With the improvement of China's comprehensive strength, cultural self-confidence and strategy are being paid more and more attention by scholars; with the future research of China's cultural and creative design theory, cross-integration becomes the future trend; with the gradual maturity of China's cultural and creative design methodology, how to choose the right method for pioneering research is a difficulty for the future development of cultural and creative design; with the continuous development of China's economy, the method construction of innovative cultural and creative industry system becomes the focus of future research; with the continuous progress of science and technology, the integration of emotion and product industry is the mainstream of future development on cultural and creative design.

Through an objective empirical analysis of the development of Chinese cultural and creative products, it will broaden the research horizons of relevant scholars, understand the development direction of China's cultural and creative industries, enrich the design practice application of Chinese cultural and creative products, enhance the understanding of international counterparts on Chinese cultural and creative design research and promote the exchange among international counterparts.

As an advanced manufacturing method, additive manufacturing (AM) technology provides new possibilities for efficient production and design of parts. However, with the continuous expansion of the application of AM materials, subtractive processing has become one of the necessary steps to improve the accuracy and performance of parts. In this paper, the processing process of AM materials is discussed in depth, and the surface integrity problem caused by it is discussed.

Firstly, we listed and analyzed the characterization parameters of metal surface integrity and its influence on the performance of parts and then introduced the application of integrated processing of metal adding and subtracting materials and the influence of different processing forms on the surface integrity of parts. The surface of the trial-cut material is detected and analyzed, and the surface of the integrated processing of adding and subtracting materials is compared with that of the pure processing of reducing materials, so that the corresponding conclusions are obtained.

In this process, we also found some surface integrity problems, such as knife marks, residual stress and thermal effects. These problems may have a potential negative impact on the performance of the final parts. In processing, we can try to use other integrated processing technologies of adding and subtracting materials, try to combine various integrated processing technologies of adding and subtracting materials, or consider exploring more efficient AM technology to improve processing efficiency. We can also consider adopting production process optimization measures to reduce the processing cost of adding and subtracting materials.

With the gradual improvement of the requirements for the surface quality of parts in the production process and the in-depth implementation of sustainable manufacturing, the demand for integrated processing of metal addition and subtraction materials is likely to continue to grow in the future. By deeply understanding and studying the problems of material reduction and surface integrity of AM materials, we can better meet the challenges in the manufacturing process and improve the quality and performance of parts. This research is very important for promoting the development of manufacturing technology and achieving success in practical application.

This paper aims to investigate the differences in hot corrosion behavior of the GTD222 superalloy and TiC/GTD222 composite in a mixed salt of 75% Na₂SO₄ and 25% K₂SO₄ at 900°C.

The GTD222 superalloy and TiC/GTD222 nickel-based composite were prepared using selective laser melting (SLM). Subsequently, the hot corrosion behavior of the two alloys was systematically investigated in a salt mixture consisting of 75% Na₂SO₄ and 25% K₂SO₄ (Wt.%) at 900°C.

The TiC/GTD222 composite exhibited better hot corrosion resistance compared to the GTD222 superalloy. First, the addition of alloying elements led to the formation of a protective oxide film on the TiC/GTD222 composites 20 h before hot corrosion. Second, TiC/GTD222 composite corrosion surface has a higher Ti content, after 100 h of hot corrosion, the composite corrosion surface Ti content of 10.8% is more than two times the GTD222 alloy 4% Ti. The Ti and Cr oxides are tightly bonded, effectively resisting the erosion of corrosive elements.

The hot corrosion behavior of GTD222 superalloy and TiC/GTD222 composites prepared by SLM in a mixed salt of 75% Na₂SO₄ and 25% K₂SO₄ was studied for the first time. This study provides insights into the design of high-temperature alloys resistant to hot corrosion.