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自然科學 大學

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Multiple-choice questions: (70 points) write the letter of statement that is not true: 1. A.B.U The Drude Model: (a) It is a classical approach using concepts from the kinetic theory of gases. (b) A relaxation-time approximation is used where the probability of collision is l/t. (c) No forces act on the electrons in between collisions. (d) It predicts accurately the electronic heat capacity of metals. 2. The Sommerfeld Model: (a) The crystal potential is replaced by an average Coulomb potential. (b) The separation of states is so close that a continuum model can be applied. (c) The electrons are highly localized due to a strong crystal potential. (Q) The energy of the highest occupied state at 0 K is the Fermi energy. 3. Density of states in k-space, N(k): (a) N(k) is determined by the boundary value conditions. (b) For lattices in any dimensions, N(k) is constant in k-space. (C) N(k) depends on the direction and magnitude of k. (d) It is directly proportional to the volume of the crystal. E影響, c 4. The Fermi surface of a metal: (a) is responsible for many of the transport properties of the metal, (b) depends on the nature of the chemical bonds, (c) is always a sphere, (d) can involve mixing of electron orbitals. ✓ 5. The conductivity of a material () increases with the mobility of its carriers, (b) increases with the density of carriers, (C) it is inversely proportional to the energy gap. cogu changes with temperature. 6. BID Plasmons: (a) They are an important characteristic of the Sommerfeld electron gas model. (b) Plasmons occur spontaneously in metals. (c) They are related to charge density oscillations. (d) The Plasmon energy is typically of the order of 10 eV. The Fermi energy Ef in intrinsic semiconductors 8) is usually close to y E, at OK (b) it ACiD. can increase or decrease with temperature depending on the ratio of hole and electron effective masses, (c) it represents the point at which the probability of occupation is 12, even though there may not been any states with that energy, (d) its value relative to the electronic bands must remain unaffected in the presence of defects or interfaces.

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英文 高中

這大題求解

... mer my friends III、綜合測驗:20% There are only a handful of underwater hotels around the world. These 16. guests to do what few people ever dream of doing: sleeping underwater. Fish, of course, do this all the time, but to humans the thought of 17... one's head on the seabed isn't very appealing. That's because mammals like us 18. have sufficient air to breathe. 19. _ ever wondered, therefore, how sea mammals, like whales, manage to get their beauty sleep? A number of 20. have attempted to answer this question. They seem to suggest that whales make use of an 21. sleep technique known as “logging." During "logging," whales are 22. to shut down just one half of their brains. This enables them to get some much-needed rest, and yet at the same time remain alert enough to regularly return to the surface of the water to breathe. 23. another sea creature that makes use of "logging" to survive is the dolphin. _ 24._ Whales, which can remain underwater for up to ninety minutes, dolphins need to breathe in fresh air above the surface every twenty minutes. Thus for them it's even more important to keep half their brains awake at all times. Logging helps them 25. this. At the end of the day, this is just another example of how human and animal sleep habits are different in strange yet wonderful ways. ( ) 16. (A) let (B) allow (C) make (D) have ( ) 17. (A) throwing (B) burying (C) laying (D) lying ( ) 18. (A) must (C) can (D) will ( ) 19. (A) Will you (B) Do you (C) Are you (D) Have you ( ) 20. (A) secrets (B) habits (C) studies (D) facts ( ) 21. (A) amazed (B) amazing (C) amaze (D) amazingly ( ) 22. (A) able (B) possible (C) capable (D) likely ( ) 23. (A) Just (B) SO (C) Also (D) Yet ( ) 24. (A) As (B) TO (C) With (D) Unlike ( ) 25. (A) achieving (B) achieve (C) be achieved (D) to achieving (B) may V. 文意選填:10%(請忽略大小寫) (A) in fact (B) however (C) amazing (D) standing (E) much Animals sleep in incredible ways. They don't need to lie in bed for hours like we do. Zebras an elephants, for example, can stay 26. while they sleep. This odd sleeping position sound uncomfortable, but it's 27. safer. Predators are always around to catch sleepy prey animals Elephants, therefore, are only away in dreamland for around 3.5 hours a day, Zebras are reported to slee even less. Giraffes, 28., sleep the least of any animal. An average of half an hour per day is usuall all they need to survive in the wild. 29. __, they hardly ever sleep for more than five minutes at a time That's simply 30. __! Can you imagine sleeping on your feet and for less than an hour a day? 6. 27. 28. 29. 30. . among Among Among fantasy novels, A song of favorite. my Ice and Fire is 在 入 267 A 面尚有試題) 6100182 Perguse

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數學 高中

這大題求解

II、綜合測驗:20% There are only a handful of underwater hotels around the world. These 16. guests to do what few people ever dream of doing: sleeping underwater. Fish, of course, do this all the time, but to humans the thought of 17._one's head on the seabed isn't very appealing. That's because mammals like us 18. have sufficient air to breathe. 19. _ ever wondered, therefore, how sea mammals, like whales, manage to get their beauty sleep? A number of 20. have attempted to answer this question. They seem to suggest that whales make use of an 21. sleep technique known as “logging.” During "logging," whales are 22. to shut down just one half of their brains. This enables them to get some much-needed rest, and yet at the same time remain alert enough to regularly return to the surface of the water to breathe. 23._ another sea creature that makes use of “logging" to survive is the dolphin. _24. Whales, which can remain underwater for up to ninety minutes, dolphins need to breathe in fresh air above the surface every twenty minutes. Thus for them it's even more important to keep half their brains awake at all times. Logging helps them 25. this. At the end of the day, this is just another example of how human and animal sleep habits are different in strange yet wonderful ways- ( ) 16. (A) let (B) allow (C) make (D) have ( ) 17. (A) throwing (B) burying (C) laying (D) lying ) 18. (A) must (B) may (C) can (D) will ( ) 19. (A) Will you (B) Do you (C) Are you (D) Have you ( ) 20. (A) secrets (B) habits (C) studies (D) facts ) 21. (A) amazed (B) amazing (C) amaze (D) amazingly ( ) 22. (A) able (B) possible (C) capable (D) likely ) 23. (A) Just (B) So (C) Also (D) Yet ) 24. (A) As (D) Unlike ) 25. (A) achieving (B) achieve (C) be achieved (D) to achieving (B) TO (C) With V. 文意選填:10%(請忽略大小寫) A) in fact (B) however (C) amazing (D) standing (E) much Animals sleep in incredible ways. They don't need to lie in bed for hours like we do. Zebra phants, for example, can stay 26. while they sleep. This odd sleeping position comfortable, but it's 27. safer. Predators are always around to catch sleepy prey a phants, therefore, are only away in dreamland for around 3.5 hours a day. Zebras are reported a less. Giraffes, 28. sleep the least of any animal. An average of half an hour per day is hey need to survive in the wild. 29. they hardly ever sleep for more than five minutes af fost and for less than an hour a day?

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