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[主观题]
In a digital cable system, if there is no key to decode the signal, then, we will only see
______.
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发布时间：2022-01-07
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更多“In a digital cable system, if …”相关的问题
第1题
In the sampling process, if the sampling period is larger than the Nyquist interval, then the sampled signal can be completely described by the sample values.()
第2题
Because they operate in a(n) _____ industry, a fare decrease at American Airlines will likely result in decreases at Continental, United, and other carriers.
A、socialistic
B、monopolistic
C、oligopolistic
D、noncompetitive
第3题
You change the price for the current validity period in an info record.There are still two purchase orders for this material that is open for delivery from the relevant vendor.What happens when the price is changed in the info record? Please choose the correct answer.()
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A.The moving average price of the material is recalculated
B.Invoice verification automatically receives a message about the price change made
C.The new price is immediately proposed for all new purchase orders created for the relevant material with the respective vendor
D.The PO price in the purchase orders that are still open is automatically changed to the new price
第4题
True or false 1. Most universities and scholarship programs in the west require one recommendation letter as part of the application process. 2. References are usually written by your friends and parents. 3. A reference letter is more general in nature than a letter of recommendation. 4. In a letter of recommendation, the writer should know the candidate well enough to evaluate their abilities and details the candidate's accomplishments and skills that make him a strong contender based on the writer’s personal experience with this candidate. 5. A letter of reference should be addressed to a specific recipient. 6. Recommendation letters help to shed light on the “full package” that is difficult to fully convey in a resume and personal statement. 7. For most job applications, a well-written resume and cover letter are more than enough. However, certain industries or companies may require a letter of recommendation in addition to these basic essentials. 8. The conclusion should make a clear statement of reference that flows logically from the points made in the assessment part of the letter.
第5题
Cells have several ways of ensuring that their daughters remember what kind of cells they should be. How do differentiated cells maintain their identity?
A．One of the simplest and most important is through a positive feedback loop, where a master transcription regulator activates transcription of its own gene,in addition to that of other cell-typespecific genes. Each time a cell divides, the regulator is distributed to both daughter cells, where it continues to stimulate the positive feedback loop.?The continued stimulation ensures that the regulator will continue to be produced in subsequent cell generations.?Positive feedback is crucial for establishing the “self-sustaining” circuits of gene expression that allow a cell to commit to a particular fate—and then to transmit that decision to its progeny.
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B．Although positive feedback loops are probably the most prevalent way of ensuring that daughter cells remember what kind of cells they are meant to be,there are other ways of reinforcing cell identity. One involves the methylation of DNA．In vertebrate cells, DNA methylation occurs on certain cytosine bases. This covalent modification generally turns off the affected genes by attracting proteins that bind to methylated cytosines and block gene transcription. DNA methylation patterns are passed on to progeny cells by the action of an enzyme that copies the methylation pattern on the parent DNA strand to the daughter DNA strand as it is synthesizeD
C．Another mechanism for inheriting gene expression patterns involves the modification of histones. When a cell replicates its DNA,each daughter double helix receives half of its parent’s histone proteins, which contain the covalent modifications that were present on the parent chromosom
E．Enzymes responsible for these modifications may bind to the parental histones and confer the same modifications to the new histones nearby. It has been proposed that this cycle of modification helps reestablish. the pattern of chromatin structure found in the parent chromosome
D．Because all of these cell-memory mechanisms transmit patterns of gene expression from parent to daughter cell without altering the actual nucleotide sequence of the DNA,they are considered to be forms of epigenetic inheritanc
E．These mechanisms, which work together, play an important part in maintaining patterns of gene expression, allowing transient signals from the environment to be remembered by our cells—a fact that has important implications for understanding how cells operate and how they malfunction in diseas
E．
第6题
用sharp的正确形式完成句子1. This knife needs??????...
| 用sharp的正确形式完成句子 |
| 1. This knife needs____． 2.The report was____critical of the police. 3. He was very____with me when I was late. |
第7题
as the figure, The relation between the current I1 and I2 is ( ) 
A、I1+ I2 =1
B、I1+1 =I2
C、I1=I2 +1
D、I1+I2 =-1
第8题
回答题。
Generations of Americans have been brought __ 26 __ to believe that a good breakfast is impor-tant for health．Eating breakfast at the __ 27 __ of the day, we have all been ． __ 28 __ , is as necessaryas putting gasoline in the family car __ 29 __ starting a trip．
But for many people the thought of food first in the morning is by __ 30 __ pleasures．So __ 31 __ all the efforts, they still take no __ 32 __ ．Between 1978 and 1983, the years for which figures are __ 33 __ ,the number of people who didn' t have breakfast increased __ 34 __ 33 percent from 8．8 million to 11．7 million __ 35 __ the Chinese-based Market Research Corporation of America．
For those who feel pain of __ 36 __ about not having breakfast, __ 37 __ , there is some goodnews．Several studies in the last few years __ 38 __ that, for adults especially, there may be nothing __ 39 __ with omitting breakfast．"Going __ 40 __ breakfast does not affect __ 41 __ "Said Arnold E．
Bendoer, former professor of nutrition at Queen Elizabeth College in London, __ 42 __ does givingpeople breakfast improve performance．
__ 43 __ evidence relating breakfast to better health or __ 44 __ ．performances is surprisingly inadequate, and most of the recent work involves children, not __ 45 __ "The literature," says one researcher, Dr．Ernesto Pollitt at the University of Texas,"is poor．"
第26题__________ 查看材料
A.about
B.into
C.up
D.from
第9题
An analog signal m(t) with zero mean is a stationary process. Its frequency range is 0(Hz) ~ 8000(Hz) and its amplitude is uniformly distributed between -5(V) ~ +5(V). Then, the minimum Nyquist sampling frequency for this signal m(t) is f (Hz) , the average power is P (W). Assuming a uniform quantizer for this signal and the step size is D=0.04(V), the minimum number of quantization bits is R .
A、f=8000, P=25, R=8
B、f=16000, P=25/2, R=7
C、f=8000, P=25/3, R=9
D、f=16000, P=25/3, R=8
