15 research outputs found
Influences of soldering time on wettability and intermetallic phase between Sn-3.0Cu solder and copper substrate
Get PDFIn this paper, the influences of soldering time on the wettability and intermetallic phase between Sn-3.0Cu lead-free solder and copper substrate were investigated. Reflow soldering was performed at 350 ° C under variable soldering times of 10, 20, 40, 60, 120, 240 and 480 s. The results indicated that the wettability and intermetallic growth depend on the soldering time. In addition, the Cu6Sn5 and Cu3Sn intermetallic phases with a hexagonal crystal structure were found between the lead-free solder and the copper substrate. The growth of intermetallic phases increased with soldering time, and the growth of intermetallic phases remarkably depended on grain boundary diffusion and was volume diffusion-controlled for Cu6Sn5 and Cu3Sn, respectively
Effect of soldering condition on formation of intermetallic phases developed between Sn–0.3Ag–0.7Cu low-silver lead-free solder and Cu substrate
No full textKaki khong Hem Wetchakon
No full textIn this article, the author describes a portrait of Kaki, a female character in Thai well-known literature. The portrait was drawn by Hem Wetchakon. The author also presents the poem written by Prince Kung describing the beauty of Kaki
Phit chom Meri loet lam loki kam ru thakon
No full textDrawing on a portrait and old poem, the author describes the beauty of Nang Meri, a female character in one old Thai literature
Nang Sida rudi din yu daeyan
No full textThe author presents poems that describe the beauty of Sida. Sida is a leading female character in the Ramayana story
He sangwat khong Chaofa Kung
No full textThe article focuses on the story of Chaofa Kung and his works. Chaofa Kung is the Thai greatest poet. His poems mostly are erotic. The author describes that Chaofa Kung's erotic poems are very beautiful
Nariphon (2)
No full textThe author describes the mural painting at Wat Nongyaosung located in Saraburi province. He writes that this mural painting is huge and it illustrates the beautiful graphics of ""Nariphon"" and ""Wichathon""
Angular Displacement Sensor Based on Coplanar Waveguide (CPWs) Loaded with S-Shaped Golden Spiral-Tapered Split Ring Resonators (SGS-SRRs)
No full textAbstractAn angular displacement sensor based on coplanar waveguides (CPWs) loaded with s-shaped golden spiral-tapered split ring resonators (SGS-SRRs) is proposed in this paper. The proposed device is composed of a CPW and a SGS-SRR which was designed based on the golden ratio number and etching on double copper layer of PCB. The transmission coefficient (S21), linearity and sensitivity of the sensor were simulated and analyzed using electromagnetic models. The results show that the sensor was able to sense the rotation angle. It has a wide dynamic range, high linearity, higher sensitivity and lower cost, which is particularly suitable for use as a sensor and transducer technology in the future
An Application of Cuckoo Search Algorithm for Series System with Cost and Multiple Choices Constraints
No full textAbstractThis paper presents an application of Cuckoo Search Algorithm (CSA) for solving reliability optimization problems for a series system. The aim of research is to select hardware from multiple choices for each subsystem to maximize the overall of system reliability and under cost constraints. CSA is a new metaheuristic algorithm inspired from behavior of Cuckoos laid their eggs in the nests of other species with the Lévy flight distribution. The effectiveness of the proposed algorithm has been evaluated with two groups of examples from the existing literature. The computational results show that the CSA has effectively been able to find the global optimal solution
Motivating Inquiry-Based Learning Through a Combination of Physical and Virtual Computer-Based Laboratory Experiments in High School Science
No full textThis chapter presents research about a combination of physical experimentation (PE) and virtual experimentation (VE) in computer-based inquiry learning as an instructional value to students' affective domain. For this study, the author has developed a science lesson for promoting interactive inquiry learning, and the researcher investigated whether orchestrating PE and VE in sequential learning affect students' learning perception and science motivation. To evaluate the lesson, questionnaires were used to examine how students perceived the lesson and their perceptions about how the lesson promotes science motivation. The results indicated students' positive perceptions that experiencing the lesson supported cognitive performance, emotional practice, and the social inquiry process. In addition, exposure to the lesson improved students' science motivation for both females and males. This highlights that the combination is an effective way to enhance the effectiveness of high school science learning. </jats:p
