提高传热温度差为什么能改善传热效果?

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提高传热温度差为什么能改善传热效果?

考点:催化裂化装置操作工中级催化裂化装置操作工中级催化裂化装置操作工题库
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作业机可以进行油、气水井的大、小修等维修作业。

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阅读理解。

     Sydney-A shark savaged a schoolboy's leg while he was surfing with his father at a beach in Sydney

on

February 23.It was the third shark attack along the coast of Australia's largest city in a month.

The 15-year-old boy and his father were in the water off Avalon. , on Sydney's northern beaches,

around dawn when he was attacked. The city's beaches are packed with locals and tourists during the

summer months.

    "The father heard a scream and turned to see his son thrashing(激烈扭动)about in the water. ,

"police said. "Fortunately. , the shark swam away and the boy was helped to the shore by his father."

Lifesaving Club spokesman Nick Miller said. , "It got him around the top of his left leg and the father

came and dragged him out of water." He said the boy was bleeding heavily when he was brought to

the shore. "There was a lot of pain, as you can imagine. "The teenager was airlifted to hospital for

treatment for leg injuries.

   Police said the bites "cut through to the bone". , but the boy did not app ear to have sustained any

fractures (骨折). He was in a stable condition now.

   Several beaches were closed after the attack. Water police and lifeguards were searching for the

shark. , while police hoped to identify its species by the shape of the bite marks. But they said it was

too early to say what type of shark attacked the boy. "I don't even know if he saw it. , "Miller said.

    Many shark species live in the waters off Sydney's beaches. , but attacks on humans are still

relatively rare. However. , there were two attacks on successive days earlier this month. , one on a

navy diver in Sydney harbor. , not far from the famous Opera House. , and  the other on a surfer at

the city's world-famous Bondi beach.

    Fishermen say shark numbers are on the rise. There is a ban on commercial fishing in the harbor

, which has increased fish stocks. Marine experts also claim environmental protection has created a

cleaner environment, attracting sharks closer to the shore as they chase fish. Many shark species

, including the Great White-the maneaters made famous in Steven Spielberg's Jaws-are protected in

Australian waters.

1. The report mainly tells us ________.

A. shark attacks on humans are on the rise

B. sharks attacked humans three times in one month

C. a boy was attacked by a shark at a Sydney beach

D. shark numbers are increasing in the waters off Sydney's beaches

2. The underlined word "savaged" in the first paragraph probably means "________". 

A. attracted  

B. dragged      

C. bit                    

D. packed

3. What do we know about the city of Sydney from the passage? 

A. It is one of the largest cities in Australia.

B. Sydney harbor is not far from the famous Opera House.

C. There are many locals and tourists on its coast all the year round.

D. There are few shark species in the waters off Sydney's beaches.

4. About the injury of the boy we know that ________.

A. he was losing much blood when he was dragged out 

B. he was very nervous when he was sent to hospital

C. he may be in danger of losing his leg

D. he was injured in the right leg

5. All the following  are the causes of Australia's sharks' increasing EXCEPT that ________. 

A. environmental protection has created a cleaner environment

B. a ban on commercial fishing has increased fish numbers

C. many shark species are protected in Australian waters

D. the film Jaws has made the Great White famous

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药物不良反应()。

A.一般都很严重

B.发生在大剂量情况下

C.产生原因与药物作用的选择性高有关

D.发生在治疗剂量

E.可以避免

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各级医疗机构发现符合病例定义的基孔肯雅热疑似、临床诊断或确诊病例时,应于()内进行网络报告。()

A、2小时

B、6小时

C、12小时

D、24小时

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文学创造客体的涵义包含哪三个方面?

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