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已知等差数列 {an} 中, a2=5,a4+a6=22 ,数列 {bn} 中, b1=3,bn=2bn1+1(n2) .
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火炸药的绿色制造技术发展

 以硝基化合物为代表的含能材料是火炸药技术的基础,其传统的制造工艺过程会产生含有大量有机物的废酸和废水,环境污染严重,治理费用高,因此火炸药原材料组分传统制造工艺需要进行绿色化和低成本改进,以及积极开发含能材料的绿色合成工艺。

硝基含能化合物的生物合成是火炸药原材料制造技术中最新颖的前沿研究领域,是一种真正绿色合成路线。最具代表性的新型硝化技术是用N2O5作为绿色硝化剂,这一技术的关键是如何制备N2O5和怎样实现N2O5硝化工艺。

研究的N2O5制备方法主要有半渗透膜电解法和臭氧氧化法:1)半渗透膜电解法是在电解池内用特制的半渗透膜隔开两个电极,电解无水硝酸而生成N2O5;2)臭氧氧化法是将浓度5%~10%的臭氧与氧气的混合物和N2O4进行气相反应生成N2O5

试验的N2O5硝化工艺主要有2种:1)用N2O5-HNO3-N2O4作硝化剂进行硝化;2)用N2O5和无水HNO3于液态二氧化碳中进行硝化。

南京理工大学研究了用DADN原料在N2O5-HNO3体系中绿色硝解制备HMX。以DADN为原料,不同硝解方法的优缺点比较见下表:

硝化体系

收率/%

优点

缺点

HNO3

40

步骤简单

得率低

H2SO4、NH4NO3、HNO3

80-85

工艺成熟

废酸量大,难处理

P2O3-HNO3

99

得率高,纯度好

P2O3和HNO3需大大过量,腐蚀性大

N2O5-有机溶剂

65

无需废酸处理

得率低,溶剂易挥发

N2O5-HNO3

94

得率高,废酸少,硝化剂的过量比小

火炸药的安全使用知识有:防止炸药受热、火焰引起的爆炸;按炸药使用温度使用,不 要超过温度条件;禁止长时间阳光照射;禁止电焊、气焊、气割作业等。

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    “When in Rome, do as the Romans do”, so when you want to do business in France, you have to get to know French culture, to make marketing plans, and to run your business by local laws.

    ____ The French take great pride in their language, so anyone who does not speak it may run the risk of being disrespected by his French colleagues or business partners. Also, another reason why learning French is important is that it is a great way to show every possible French business partner that you care and respect their country's culture and language.

    There are obvious ways of greeting people in French. When you meet someone new, it's usual to shake his hand firmly and always look at the person in the eye. ____

        Dress well. ____Your business clothing is a reflection of your success and social status. Always try to be stylish. Women are advised to dress simply but elegantly. Wearing make-up is practiced widely by business women.

    The French are passionate about food, so lunches are common in doing business in France, which usually consist of an appetizer, main meal with wine, cheese, dessert and coffee, and normally take up to two hours. ____

    Do not begin eating until the host says, “Bon appetite”. Pass dishes to the left, keep wrists above the table and try to eat everything on the plate. ____This may suggest that you find the food tasteless. If eating in a restaurant, the person who invites always pays.

A. The French draw information about people based on their appearance.

B. This is a time for relationship building.

C. Maybe you have heard the expression.

D. Language should be the focus of anyone planning to do business in France.

E. Be careful with adding salt, pepper or sauces to your food.

F. When you meet a friend, kissing is common.

G. English and French are both spoken in formal occasions.