昆虫标本的修补和处理

一、折断标本的修补: 昆虫标本在采集,制作过程中难免有损伤折断的可能,尤其是触角和蝶类中凤蝶的“尾突”更容易折断,在制作标本时应及时修补。“尾突”修补时可先将标本反放在展翅板或泡沫塑料板上,然后剪一片比碎翅较小些的透明纸,纸上涂上万能快干胶,贴在翅的反面,再将标本翻过来,把折断的“尾突”贴在透明纸上,就能使标本完整。折断的触角或部分虫体可直接用万能快干胶粘接,但胶液要适量以免干后有胶液凝结的痕迹而影响美观。     

电位滴定中的对称反应探讨

用与讨论Ce4＋和Fe2＋的反应相似的方法．判断一个反应是否为对称反应,应该看滴定曲线上电位突跃点和化学计量点是否重合．重合者为对称反应,否则为非对称反应,若从反应物之间的摩尔比或看氧化还原反应中氧化剂和还原剂得失电子数目是否相等去判断一个反应是否为对称反应,有时会导致错误的结论．只有把对称反应的电位突跃点当作化学计量点在理论上才是严谨可靠的．     

化蝶

蝶破茧而出的时候,会疼吗？ 从笨拙的躯壳中挣扎着伸出细嫩的触角,翅膀因为粘满液体依旧合拢,几乎透明的足肢,支撑着颤抖的身体,微风吹过,它摇晃着几乎倒下。只有耐心等待。阳光的照耀使它慢慢变得轻盈,那薄而绚烂的翅翼上色彩一点点明媚起来。空气中舶温度通过触角传遍全身,让它,分一秒地强壮起来。然后,你几乎听到一声轻轻的叹息,那是终于自由的释怀。一展翅,它起飞。     

触角

孩子们心灵的“触角“特别多,而且特别敏感,所以我尽量用好的感觉去触及他们.我知道,如果我让他们发现一点点异样,这些敏感的“触角“就会像含羞草遇到刺激一样立刻收缩起来,而要想再次叩开他们心灵的大门,则是一件十分艰难的事.……     

触角

孩子们心灵的“触角”特别多,而且特别敏感,所以我尽量用好的感觉去触及他们。我知道,如果我让他们发现一点点异样,这些敏感的“触角”就会像含羞草遇到刺激一样立刻收缩起来,而要想再次叩开他们心灵的大门,则是一件十分艰难的事。     

电位滴定中的对称反应探讨

用与讨论Ｃｅ＾４＋和Ｆｅ＾２＋的反应相似的方法。判断一个反应是否为对称反应,应该看滴定曲线上电位突跃点和化学计量点是否重合。重合者为对称反应,否则为非对称反应,若从反应物之间的摩尔比或看氧化还原反应中氧化剂和还原剂得失电子数目是否相等去判断一个反应是否为对称反应,有时会导致错误的结论。只有把对称反应的电位突跃点当作化学计量点在理论上才是严谨可靠的。     

松毛虫赤眼蜂雌性触角五种感器的超微结构(膜翅目:赤眼蜂科)

利用透射电镜研究了松毛虫赤眼蜂(Trichogramma dendrolimi)雌性触角5种感器。观察到毛形感器远端神经树状突膨大成为外节,外节的端部有细管体,说明它是属于机械感器,具有触觉的功能。刺形感器和坛形感器是化学感器,前者的角质壁上见有嗅孔分布,后者角质壁出现11～13条纵列狭窄的凹沟,每条凹沟都通向内部的大室。i型感器有两种形态:i型I占绝大多数,在其角质壁上无嗅孔,感觉神经树状突分布在感器的内腔中,可能是一种具有触觉作用的机械感器;极少数为i型Ⅱ,在毛的内腔出现大室和小室,感觉神经树状突只伸向内腔的小室,根据有大、小室的存在,它们具有味觉作用,但从它的基部收缢的特点,说明又有触觉的功能,所以是具有双重性质的感器。至于栓锥感器,树状突出现在内腔,但从结构上没有嗅孔这一特征分析,可以归属为机械感器。     

昆虫之最

最重的昆虫非洲近赤道地区金龟子科的一种甲虫,成年雄性个体重量为70.95～99.33克。最长的昆虫印度尼西亚的一种大竹节虫,至今所测得的最长的一个雌性个体长达33.02厘米。现知最长的甲虫(包括触角)是美洲中南部的一种独角仙,已测得最大体长达到19厘米,但体长的一半被前胸角突占去。最小的昆虫     

大直径圆弧齿轮切齿深度的测量

通过对目前圆弧齿轮切齿深度常用的几种测量方法的比较，提出了大直径圆弧齿轮切齿深度的控制最好采用检测全齿深这一方面，该方法简便易行，有效地控制了齿轮的精度，从而大大降低了废品的产生。     

氧化还原滴定化学计量点在滴定突跃中的位置

氧化还原滴定在选择指示剂时应该注意化学计量点在滴定突跃中的位置。 不同类型的氧化还原反应,其化学计量点在滴定突跃中的位置如何,华中师范大学等三校编《分析化学》教材中,只是定性地指出:在氧化剂和还原剂两个半反应中,若转移的电子数相等,即n_1=n_2则化学计量点应为滴定突跃的中点。若n_1≠n_2,则化学计量点偏向电子转移数较多(即n值较大)的电对一方;n_1和n_2相差越大,化学计量点偏向的越多。此结论未作理论推证。本文通过数学推论,得出化学计量点在突跃中的确切位置的计算公式,将上述定性的结论提高到定量上来讨论。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

胡主席在印度,我却在中国

Today, Sunday morning, I sit thinking and typing at my computer. My thoughts are in my homeland, India and my body is in China. The body is here and mind there for a good reason. Mr. Hu is president and I am resident and both are in each other's countries (what a difference the absence of one small letter makes!). Mr. Hu will return in a few days and I will stay on longer.