Experiment § The difference between mercury lamp and UV LED lamp
When using light-curable resins, in addition to the formulation itself, which affects the properties, the light source is also an important factor. In the past, we used mercury lamps or halogen lamps, but now we have more LED lamps to choose from. Because LED lamps have the advantages of low power consumption, long life (10,000 hours), miniaturization, and energy-saving than traditional mercury lamps or halogen lamps, customers who use UV LED lamps are slowly increasing. At present, UV LED mainly has several wavelengths such as 365, 385, 395, and 405nm to choose from. The difference between UV LED and traditional mercury lamp is that it has a single wavelength. Taking 395nm as an example, the light source of UV LED will be concentrated around 395nm, and will not produce ultraviolet light of other wavelengths. This phenomenon causes a big difference between the two. According to a certain free radical polymerization as an example, under the same irradiation energy, the cured adhesion strength of the LED lamp and the mercury lamp are 95 and 198kg. This difference is usually related to the narrow wave domain of the LED lamp and the lack of other short-wave (365, 254nm) energy. Customers need to adjust the curing conditions, or we need to change the absorption wavelength of the initiator in order to obtain good results. However, there are also examples where the effect of LED lamps is better than that of mercury lamps. For example, the application with a large curing depth: the unit illuminance of the LED lamp is often larger than that of the flat mercury lamp (the former can reach 3000, and the latter 80~120 mW/cm2), so when the wavelength is appropriate, there is a good curing depth in some ionic polymerization systems, this characteristic is critical. In general, mercury lamps and UV LED lamps are different light sources, because even if the maximum intensity wavelength is the same (for example, the most common 365nm), the characteristics of the resin after curing may be quite different. Before choosing two different light sources, it is necessary to conduct careful tests with the material supplier.
─Author: Mr. Dong-Qi, Pan
Activity § Eat at Everwide
Our lunch is provided by the company, and there are two types for colleagues to choose from.
1/3 of my colleagues enjoy the "special meal" of the company kitchen: organic vegetables and special rice purchased by Douliu Farmers Association. Two-thirds of my colleagues enjoy the purchased bento, and the colleagues take turns to decide which one and which flavor to eat, and the meal budget is 60 yuan per person. The dining environment is more diverse, some in the restaurant, some in the dormitory, and some in the lounge. You can claim the missed meal fee for overtime work beyond 7 pm, and when you work overtime on Saturday, you can order an extra drink to show your comfort. Eating at Everwide is still a bargain, right?
Knowledge § What is the change in Tg under different heating rates for the same test piece tested by DSC?
The faster the DSC heating rate, the higher the measured Tg value. When publishing data on thermal properties, the heating rate should be noted. Generally, 10℃/min is the most common. This phenomenon has the same trend in many thermal analysis experiments: using DSC to obtain the starting temperature and the maximum reaction temperature. The Tg is determined by the change in the expansion coefficient of TMA. The Tg is determined by Tanδ of the DMA map. Using TGA to measure the pyrolysis temperature, etc. will be affected by the heating rate of the instrument. The faster the heating rate is the measured thermal property signal shifts to high temperature.
Living § Small wish
After I received the salary of my first full-time job in my life, the first thing I did was to participate in the "World Vision-Child Support Project". In this world, there are many children who need help. They may face the dangers of famine, poverty, and war. Can you grow up? Where is the future? They may not find the answer. The official website of World Vision: "Help a foreign child by 700 yuan a month, so that his life growth will be changed." How to deposit 700 yuan a month? It's actually not difficult. Drink one drink less a day and you can save 700 yuan a month! I never knew how effective my funding could be until I received a letter from Qiu An, my first sponsored child. The letter reads like this: "Dear sponsor, I am from Guatemala, thank you very much for your help in allowing me to go to school, so that our family of 11 can have enough food and clothing, thank you!" Suddenly, I was in a daze for a long time. It turns out that 700 yuan, which is small in our eyes, is so powerful. I began to pass this plan to every friend around me, and everyone also aspired to join the sponsored children plan. In fact, there are friends around me who have received funding from the World Vision Funding Program. Because of family factors, his study career has been difficult. World Vision will take the initiative to help him and publish his news on the official website. He was studious and received funding from a foreign couple for 15 years until he graduated from university. He was grateful, and decided to join the ranks of funding after he retired from the army, together to pass on the love in his heart to the people in need of help in the world! This tiny power may be far less than the financial aid of the big consortium, but everyone can choose their own way to spread their love and power to people you don't know in the world. I also believe that these forces will continue to make the world a better place!
─Author: Ms. Heng-Rong, Li
Go Kaohsiung
A gas explosion occurred in Kaohsiung on July 31, causing everyone to fall into extreme horror and sorrow. As a member of Taiwanese society, Eveewide Chemical is willing to donate 1 million yuan to help Kaohsiung quickly be rescued from the disaster.For related information, please refer to the following link: http://www.thenewslens.com/post/60302/
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