approve of be highly regarded the majority of affect put it another way |
2.
3. His work
4. Your opinion will not
5. Let me
stimulate pursue contribute gain knowledge expose oneself to |
1. It’s important to
2. Honesty and hard work
3. You can’t
4. We can
5. Everyone has the freedom to
be eager to be enthusiastic about breakthrough precious apparent |
2. A family break allows you to spend
3. Don’t worry, all the people around
4. His
5. Scientists have made a
New research into EQ and IQ suggests that success is not simply the result of a high IQ. While your IQ tells you
I remember Graham was very difficult before he came into my class. I had heard stories about his bad behavior. Once I caught him and his friends seeing who could jump the farthest off the school stage! But when he got interested, he changed. The first day he walked into my class, he
It happened early on a Friday morning. Tina, a sixteen-year-old girl came to school as usual. But when she entered the classroom, she
A few days ago, I went out for a dinner get-together with some friends. My best friend left the table for 30
Most people believe when they are living
have access to associate with on behalf of belong to take up get on drop out of devote……to |
2. I’m sorry I’ve already
3. The thing about being a teacher is that you
4. I am writing
5. He had injured his leg and
6. For more than 50 years, he has
Socializing with my friends online is my life, so I’m
8 . Chinese scientists recently achieved precise total synthesis (合成) of sugar from carbon dioxide in the laboratory, marking a crucial step in artificial sugar synthesis.
The synthesis, which took more than two years to realize, was achieved by teams from the Chinese Academy of Sciences’ Tianjin Institute of Industrial Biotechnology and the academy’s Dalian Institute of Chemical Physics. Their research was published last week in a paper in Chinese Science Bulletin, a multidisciplinary academic journal.
Sugar is a major source of energy for the human body and a key raw material for industrial production, and it is mainly obtained by extracting it from crops such as sugar cane. However, the traditional method of extraction is limited by the energy conversion efficiency of plant photosynthesis. Moreover, the process of extracting sugar has been affected by uncertain raw material supplies due to land degradation and shortages, ecosystem degradation and extreme weather and natural disasters caused by global warming.
As a result, artificial sugar synthesis has been continually studied by the scientific community in recent years, and scientists around the world have contributed to the effort. In their latest research, the Chinese scientists adjusted high-concentration carbon dioxide and other raw materials in the reaction solution. With the help of chemical catalysts and enzyme (酶) catalysts, they obtained four kinds of sugars: glucose, allulose, tagatose and mannose.
The experiment lasted about 17 hours, much shorter than the time required for traditional methods of sugar extraction, according to Yang Jiangang, lead author of the paper and associate researcher at the Tianjin institute.
The efficiency of sugar synthesis in this study was 0.67 grams per liter per hour, which was more than 10 times higher than the previous results achieved by scientists worldwide. Yang said that the carbon dioxide to sugar conversion rate of glucose reached 59.8 nanomoles of carbon per milligram of catalyst per minute. This is the highest level of artificial sugar production known domestically and internationally.
The study also achieved precise control of artificial sugar synthesis. “By controlling the varied catalytic effects of different enzymes, theoretically almost any type of sugar can be synthesized,” Yang said. Regarding the study, Manfred Reetz, a member of the German National Academy of Sciences Leopoldina, said it is a particularly challenging task to convert carbon dioxide into sugars.
The achievement by Chinese scientists has provided a flexible, multifunctional and efficient sugar synthesis route, which opens a door for green chemistry, Reetz said. Green chemistry, similar to sustainable chemistry, is a rapidly developing field that focuses on how to fully utilize raw materials and energy in the process of producing the intended product while minimizing or eliminating the use and generation of harmful substances.
Carbon dioxide to sugar conversion is seen as an example of green chemistry, since it was conducted under normal temperature and pressure conditions and did not yield any harmful substances.
1. Why do scientists keep studying artificial sugar synthesis?A.Because sugar is an essential energy source for industrial production. |
B.Because the traditional extraction approach is not environmentally friendly. |
C.Because raw material supply is unreliable in the process of traditional sugar extraction. |
D.Because the traditional extraction approach is less productive than plant photosynthesis. |
A.It synthesized almost all types of sugar in the laboratory. |
B.It controlled varied catalytic effects of different enzymes. |
C.It converted high-concentration carbon dioxide into sugar. |
D.It lasted 17 hours, shorter than previous traditional methods. |
A.Green chemistry helped use up all raw materials to generate more products. |
B.Carbon dioxide to sugar conversion will be used in industrial production soon. |
C.Green chemistry is a new field where Chinese scientists will put more efforts on. |
D.Carbon dioxide to sugar conversion will take up all sugar production due to its efficiency. |
Driving to Palm Springs two years ago, I met a snowstorm. A car suddenly changed the direction
10 . The story of Jennifer Bricker is one of the most amazing story, which is full of both great surprises and life lessons.
Jennifer was born in Romania without any legs. She was later
The Brickers never let this
The girl was
But it was tumbling (翻腾运动) that was her true love. When she was a little girl, she was a big
As she grew older Jennifer began
If her story was not amazing enough already, when Jennifer turned 16, she got the most
A.adopted | B.injured | C.sold | D.seen |
A.disability | B.gift | C.excuse | D.failure |
A.signed up | B.brought up | C.put up | D.kept up |
A.roles | B.instruments | C.sports | D.tricks |
A.audience | B.athlete | C.member | D.fan |
A.performed | B.appeared | C.hosted | D.challenged |
A.competing | B.fighting | C.acting | D.going |
A.pity | B.topic | C.challenge | D.success |
A.disturbing | B.popular | C.unbelievable | D.reliable |
A.fluent | B.loud | C.silent | D.inspiring |