装有含硫原油的油罐,应定期清除罐内沉积物,以防原油质量迅速变坏。

题型:判断题

问题:

装有含硫原油的油罐,应定期清除罐内沉积物,以防原油质量迅速变坏。

考点:成品油计量工成品油计量工(中级)成品油计量工(中级)题库
题型:判断题

质量为5 kg的小球以5 m/s的速度竖直落到地板上,随后以3 m/s的速度反向弹回去,若取竖直向下的方向为正方向,则小球动量的变化为[ ]

A.10 kgm/s  

B.-10 kgm/s

C.40 kgm/s  

D.-40 kgm/s

题型:判断题

(选做题)人参是一种名贵中药材,其有效成分主要是人参皂苷。利用细胞培养技术生产人参皂苷的大致流程如图所示。请回答:

(1)配制诱导愈伤组织的固体培养基,分装后要进行______,接种前,要对人参根进行________。

(2)用于离体培养的根切成的小块叫做_______。培养几天后发现少数培养基被污染,若是有颜色的绒毛状菌落,属于_________污染;若是有光泽的黏液状菌落,属于________污染。

(3)用少量________酶处理愈伤组织,获取单细胞或小细胞团,在液体培养基中进行悬浮培养,可有效提高人参皂苷合成量。

(4)人参皂苷易溶于水溶性(亲水性)有机溶液,从培养物于粉中提取人参皂苷宜选用______方法,操作时应采用_______加热。

题型:判断题

物业管理企业享受国家对第三产业的优惠政策,应缴纳的税费是两税一费,共计为经营总 收入的( )。

A.5%

B.5.5%

C.8%

D.10%

题型:判断题

NA表示阿伏加德罗常数。则下列叙述中,正确的是

A.32g S2-中电子数目为2NA

B.46 gNO2和N2O4的混合物中含有的原子数为3NA

C.1 L 0.5 mol•L1 Na2CO3溶液中含有的CO32数为0.5NA

D.78 g Na2O2中阴离子数目为2NA

题型:判断题

My mother is a diligent and kind woman. She is very busy from morning till night. As a teacher, she works hard.  ___小题1:___ Both my brother and I love her dearly as she loves us.

My mother has been teaching math at a middle school in my hometown. She goes to work early in the morning and does not return home until late in the afternoon. ___小题2:___ She treats them with patience and teaches them well. For her excellent quality and very good teaching results, she has been elected as a model teacher several times.

___小题3:___  Every day, when she comes back home from work, she sets about doing housework, sweeping the living room and bedrooms or cleaning the furniture, and putting everything in good order. She seems to be busy all the time. As she has been very busy working every day, she looks older than her age. But she looks as cheerful and happy as ever. Mother never buys expensive dresses for herself, but she often buys some inexpensive but high quality clothes for us. ___小题4:___ She just eats a plain meal outside when she is too busy to cook herself. She lives a busy yet simple life, without any complaints.

Often she says to us, “work while you work, and play while you play. That is the way to be happy and gay. If you do not work, you will become lazy and be of no use to society”. What a piece of good advice this is!  __小题5:__ This advice of hers will always serve as a guide to my behavior. My mother is great indeed, and I always feel proud of her.

A.She enjoys listening to classic music.

B.As a mother, she takes good care of us and gives us every comfort.

C.She loves her students and cares for them.

D.She never goes to expensive restaurants to enjoy meals.E. My mother is hard-working and never wastes money.

F. I never forget it and always bear it in my mind.

G. Can you tell us something about your mother?

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