几种植物有色标本的制作

一、红色标本的制作1．药品①福尔马林硼酸溶液：在100毫升水里加1克硼酸,溶解后再加100毫升1％福尔马林,静置,取上面澄清液即可。②亚硫酸础酸液：1份1％亚硫酸和1份0．2％硼酸配制而成。2．制作选择成熟完整的红色果实,洗净后放入盛有福尔马林硼酸溶液的烧坏内,当标本由红转变为深褐色时取出。浸泡时间的长短,决定于果实大小和色彩的深浅,一般是1～3天。然后移到盛有亚硫酸硼酸溶液的标本瓶内保存。二、黄色标本的制作1．药品5％硫酸铜溶液;2％亚硫酸溶液。2．制作植物的黄色或黄绿色部分,可以浸泡在5％硫酸铜溶液中1～5天,漂洗…     

剑叶龙血树愈伤组织的诱导及其增殖培养研究

以西双版纳可提取药用活性成分“血竭”的剑叶龙血树为材料,进行愈伤组织的诱导及增殖培养,结果显示：外植体的消毒侧芽以75％乙醇浸泡2min＋0．1％升汞浸泡8min,花蕾以75％乙醇浸泡1．5min＋0．1％升汞浸泡8min,叶片以75％乙醇浸泡3min＋0．1％升汞浸泡12min效果较好;愈伤组织诱导以花蕾为外植体效果较好,且诱导与增殖的培养基为B5＋2．0mg/L NAA＋0．5mg／L6-BA．     

白纸燃尽美景现

实验过程1．将旧挂历（或旧画报）擦净浸人热饱和珊砂（或硼酸）溶液中，取出晾干后，再浸入30％的明矾溶液中，取出晾干备用．2．将加厚白纸浸入30％的硝酸钾溶液中，取出晾干，再在浓硝酸与浓硫酸（体积比按1：2）混合液中浸泡10分钟，轻轻取出后放人静水中漂洗干净（因纸易破不能冲洗），晾干后即为高速易燃纸，将它任平粘在旧挂历的景色美丽的画面上，点火后只有厚白纸迅速燃烧，而呈现出旧挂历上有美丽景色的图案．注意事项：加厚白纸在硝酸和硫酸混合液中浸泡不能超过10分钟，否则不易燃；水洗要轻，以防破裂，实验原理：1．用硼砂、…     

以不变应万变──有关溶液的稀释、浓缩、混合的计算

解决有关溶液的稀释、浓缩、混合的计算的关键是抓住在稀释、浓缩、混合前后溶质的质量不变。1．溶液稀释设有某溶液A克，百分比浓度为a％，稀释成浓度为b％的溶液B克。因稀释前溶液里的溶质质量=稀释后溶液里的溶质质量，则有A×a％=B×b％。例1配制200毫升浓度为60％（密度为1．5克／厘米3）的硫酸溶液。需要用98％（密度为1．84克／厘米3）的浓硫酸和水各多少毫升？解设需用98％的浓硫酸为V毫升，根据稀释前后溶质的质量不变可得：V=99．82（毫升）需要水的体积为：2．溶液浓缩加热蒸发掉溶液中一部分水，使溶液的浓度增大，即为溶液…     

衣物除渍

当教师的，常常要跟各种墨水打交道，不小心弄到衣物上，用一般的洗涤剂很不容易洗掉。下面向您介绍几种除溃的方法：1．除蓝墨水渍刚刚污染的衣物可先在冷水中浸泡，然后用洗衣粉或肥皂拔济。陈迹可放在2％的草酸溶液中浸泡几分钟，然后用洗涤剂洗除。2．陈红星＊温可先用洗涤     

预处理剂对非离体大豆有丝分裂的影响

采用0．1％秋水仙素溶液、0．002mol／L的8-羟基喹啉溶液、对二氯苯饱和溶液、0．1％秋水仙素溶液和0．002mol／L的8-羟基喹啉溶液混合液（V：V=1：1）、0．1％秋水仙素溶液和对二氯苯饱和溶液混合处理液（V：V=1：1）对大豆根尖进行处理,以蒸馏水处理作为对照．结果表明：各种预处理方法有丝分裂指数均比对照有所提高,分别提高了0．43％、0．41％、4．45％、1．07％、0．83％,其中提高最明显的是用对二氯苯处理的．通过方差分析和多重比较可以看出,对二氯苯处理的与其他各预处理方法的差异达极显著．     

枣制品加工

一、枣蓉罐头１．原料选择：选用八九成熟、掰开枣肉不见丝纹、个大均匀、干燥、核小、皮薄、肉质细实、味甜、无苦、酸、涩味的枣为原料。２．浸泡去核：把选好的枣倒入缸内,浸泡２４小时捞出后,用清水漂洗干净,除去异物,然后用去核机去掉枣核（亦可用手剥去核）。３...     

酒精对蟾蜍离体坐骨神经干动作电位的影响

应用电生理方法观察了不同浓度的酒精对蟾蜍离体坐骨神经干动作电位的幅度、持续时间及传导速度的影响。结果表明：用酒精溶液浸泡蟾蜍坐骨神经干10min，低浓度（1％、2％、4％）时，动作电位的幅度和对照组相比无明显变化；中、高浓度的酒精溶液（6％、8％、10％、129／6）使动作电位的幅度显著或极显著降低。动作电位的传导速度随着酒精溶液浓度的升高而变慢，和对照组相比，10％的酒精溶液使其显著减慢（P〈0．05）；12％的酒精溶液使其极显著减慢（P〈0．01）。随着酒精溶液浓度的升高，坐骨神经干动作电位持续时间有缩短趋势，但无显著性差异。这说明酒精溶液对坐骨神经干动作电位具有一定的抑制作用。     

双氧水浸种对烟草种子发芽的影响

通过对不同浓度的双氧水和不同的浸种时间的试验，结果表明：用浓度为0.15％或1．0％的双氧水浸泡烟种16小时，发芽势分别较对照组增加25％和26.4％，烟种的发芽率分别提高27．2％和27％。     

吴茱萸中总生物碱含量的测定

吴茱萸用70％乙醇浸泡、提取,得总生物碱溶液。用分光光度法,在290nm处,对总生物碱进行测定,其含量为0.5012％,平均回收率为98％。     

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,     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

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.     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

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.