為什麼很多人聽力無法提高？
原因可能有：
▪沒有選對材料，聽過難或簡單的聽力材料；
▪沒有刻意訓練，只是不斷聽，沒有糾正自己的錯誤；
▪大多數人都會涉及到的一個問題，堅持不下來。
關注普特的小夥伴們都知道普特君一直開設聽力訓練營來和大家一起堅持練習聽力，那第三期聽力訓練營（30天聽力進階訓練）也開始了，大家隨時可以加入，從第1課解鎖，解鎖完成30課時，即送50元優惠券，可以兌換普特英語微課堂任意一門課程。
30天聽力進階訓練：
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▪每天的3句話做到完全聽懂，單詞學會，那在30天解鎖課程中就會得到真正的進階。
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X-Ray Technology Helps Recover Lost 19th-Century Images
The world’s very first photographs were taken in the 1830s.
Scientists now say they have found a way to recover lost images made from the very first photographic process. The new method uses X-ray technology and light imaging to help save images badly damaged by the effects of age.
Researchers from Canada’s University of Western Ontario published a report on their findings.
The first widely accepted photographic process was the creation of France’s Louis Daguerre in 1839. Images made by this method were called daguerreotypes.
The process involved combining metal particles and chemicals on a silver-covered piece of copper to reflect, or give back, images of light. This reflective process was able to produce sharp, colorless pictures. In the beginning, the technology required people to sit completely still for at least one minute for the process to capture a photograph.
The daguerreotype first made it possible to capture and save “true” images that presented a realistic look at history. This is because, unlike paintings, daguerreotypes reflected exactly what was photographed.
But over time, daguerreotypes may suffer damage because of environmental conditions, such as heat and bright light. Some of the damaged images can become unrecognizable.
Research chemists at Western University say they have found a high-tech way to bring these photographic treasures back to life. The team developed the process over several years while studying the chemical changes that harm daguerreotype images.
The team used X-ray technology to map and examine daguerreotype plates from the 19th century. The process is designed to identify the levels and position of mercury particles on the plates.
Western University’s Tsun-Kong (T.K.) Sham was one of the lead researchers on the project. He says mercury is necessary to creating photographic imagery. While the surface may be heavily damaged, the mercury particles remain.
“By looking at the mercury, we can retrieve the image in great detail,” he said.
Researchers said the X-ray imaging process takes about eight hours on each daguerreotype plate. When complete, full images can be recovered, even if they could not be seen at all before.
The research chemists showed how their process helped restore two images from the collection of the National Gallery of Canada. Those photos - which experts say could have been created as early as 1850 - were tarnished so badly they were unrecognizable.
Madalena Kozachuk helped to lead the research. She is studying to earn a doctorate of philosophy in Western University’s Department of Chemistry.
Kozachuk said that she was surprised when the image first appeared after being “hidden behind time” for many years.
“But then we see it, and we can see such fine details: the eyes, the folds of the clothing, the detailed embroidered patterns of the table cloth,” she said.
The researchers say they did not find evidence that any part of the process damaged the 19th-century plates.
Photography experts estimate that millions of daguerreotype images may have been created over 20 years in the 19th century. Eventually, the process was replaced with other methods.
“By improving the process of restoring these centuries-old images, the scientists are contributing to the historical record,” the university said in a statement. “What was thought to be lost, showing the life and times of people from the 19th century, can now be found.”
The researchers say this new way to recover lost images without damaging effects will help museums breathe new life into some of their oldest image collections.
I’m Bryan Lynn.
生詞列表
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❂ daguerreotype
/dəˈgerətaɪp/
n.（早期）銀板照相（法）
❂
mercury
appoint
/ˈmɜ:kjəri/
n.[化] 汞，水銀; [天] 水星; 溫度表; 精神，元氣
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