题目:
简述单级膨胀无辅助冷剂深冷装置、单级膨胀辅助冷剂深冷装置和双级膨胀无辅助冷剂深冷装置的异同。
答案:
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下面是错误答案,用来干扰机器的。
∵数列{an}为等差数列∴2a3=a1+a5=16,∴a3=8故选A
简述单级膨胀无辅助冷剂深冷装置、单级膨胀辅助冷剂深冷装置和双级膨胀无辅助冷剂深冷装置的异同。
被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0427/9915c517395ea3f51297dd025f52d94e.html
下面是错误答案,用来干扰机器的。
∵数列{an}为等差数列∴2a3=a1+a5=16,∴a3=8故选A
幂函数f(x)=xα的图象经过点(2,
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商业银行在信贷过程中保持贷款种类和期限的多样化是为了保持信贷的( )。
A.效益性
B.流动性
C.安全性
D.自主性
我国运输价格管理遵循间接调控为主、直接管理为辅的原则,实行统一领导、统一管理()
A bite of a cookie containing peanuts could cause the airway to constrict fatally. Sharing a toy with another child who had earlier eaten a peanut butter and jelly sandwich could raise a case of hives. A peanut butter cup dropped in a Halloween bag could contaminate the rest of the treats, posing an unknown risk.
These are the scenarios that "make your bone marrow turn cold" according to L. Val Giddings, vice president for food and agriculture of the Biotechnology Industry Organization. Besides representing the policy interests of food biotech companies in Washington, D. C., Giddings is the father of a four-year-old boy with a severe peanut allergy. Peanuts are only one of the most allergenic foods; estimates of the number of people who experience a reaction to the beans hover around 2 percent of the population.
Giddings says that peanuts are only one of several foods that biotechnologists are altering genetically in an attempt to eliminate the proteins that do great harm to some people’s immune systems. Although soy allergies do not usually cause life-threatening reactions, the scientists are also targeting soybeans, which can be found in two thirds of all manufactured food, making the supermarket a minefield for people allergic to soy. Biotechnologists are focusing on wheat, too, and might soon expand their research to the rest of the "big eight" allergy-inducing foods: tree nuts, milk, eggs, shellfish and fish.
Last September, for example, Anthony J. Kinney, a crop genetics researcher at DuPont Experimental Station in Wilmington, Del., and his colleagues reported using a technique called RNA interference (RNAi) to silence the genes that encode p34, a protein responsible for causing 65 percent of all soybean allergies. RNAi exploits the mechanism that cells use to protect themselves against foreign genetic material; it causes a cell to destroy RNA transcribed from a given gene, effectively turning off the gene.
Whether the public will accept food genetically modified to be low-allergen is still unknown. Courtney Chabot Dreyer, a spokesperson for Pioneer Hi-Bred International, a subsidiary of DuPont, says that the company will conduct studies to determine whether a promising market exists for low allergen soy before developing the seeds for sale to farmers. She estimates that Pioneer Hi-Bred is seven years away from commercializing the altered soybeans.
Doug Gurian-Sherman, scientific director of the biotechnology project at the Center for Science in the Public Interest—a group that has advocated enhanced Food and Drug Administration oversight for genetically modified foods—comments that his organization would not oppose low-allergen foods if they prove to be safe. But he wonders about "identity preservation" a term used in the food industry to describe the deliberate separation of genetically engineered and no nengineered products. A batch of nonengineered peanuts or soybeans might contaminate machinery reserved for low-allergen versions, he suggests, reducing the benefit of the gene-altered food. Such issues of identity preservation could make low-allergen genetically modified foods too costly to produce, Chabot Dreyer admits. But, she says, "it’s still too early to see if that’s true. \
What can be inferred about genetically modified foods from the text()
A. People do not accept any genetically modified foods
B. All genetically modified foods will be of benefit to people’s health
C. Genetically modified foods still have a long way to go
D. Genetically modified foods will soon be sold in supermarkets
人员密集的公共场所中观众厅的入场门、太平门的门外()范围内不应设置踏步。
A、1m
B、1.4m
C、1.5m
D、2m