相异的

They are often morphologically distinct from A chromosomes, being smallerand more highly heterochromatic in most cases. B chromosomes do not pair with Achromosomes, and they are inherited in a non-Mendelian way, exhibiting meiotic andmitotic instability and nondisjunction. However, B chromosome DNA is quiteidentical to the corresponding sequence on the A chromosome complement. So far afew B chromosome specific DNA sequence have been identified. Specific DNAsequences on B chromosome have been the attractive research area on Bchromosomes.

现已在千余种植物和近三百种动物中被发现。B染色体与物种中正常染色体不同：独立于整倍体基因组之外，减数分裂时不与A染色体发生联会和配对，细胞分裂后期不分离，非孟德尔遗传，富含异染色质，不含对宿主主要性状有影响的基因等。B染色体DNA的分子组成既与A染色体极为相似，具有A染色体DNA分子组成的一般特征：富含重复序列和转座成分，染色体三大功能组件DNA高度同源；又与之相区别，含有B染色体特异的DNA序列，这些DNA序列可以为探讨B染色体的起源和进化提供有价值的信息。

The major concern is the characteristics and its properties of dispersion process of different mixing technology. It is suggested that the development of polyisocyanate and spray equipments be strengthened to realize the series turn of two-pack waterborne polyurethane coating and reduce the production cost.

对强力分散技术、相转化技术、自分散技术等分散过程的特点、性能和聚合物多元醇的要求进行了重点评述，并指出今后应加强对多异氰酸酯和涂装设备的开发，以利于双组分水性聚氨酯涂料的系列化及其成本的降低。

Fromthese facts,It could be deduced that 8 to 14 pairs of chromosomes possessed a certaindegree of hetorology,which was directly groved to be hybrid origin of P.tomentosaaccording to the good chromosome homology and fertility of P.bolleana and thehybrids of P.tomentosa×P.bolleana,it could be further deduced that the original parentsof P.tomentosa involved probably P.bolleana or P.alba.

从终变期、中期I的染色体构型看，有数目不等的联会程度较差的单价体和棒状二价体出现，在后期I，甚至末期I亦可见到含落后染色体分裂相的细胞，由此推断可能有8~14对染色体表现出一定程度的异源性，鉴于新疆杨以及毛白杨与新疆杨杂交产生的杂种毛新杨的染色体同源性较强、育性较好等现象，进一步推断毛白杨起源亲本可能包括新疆杨或银白杨。

For the first time, enantiomers of C2-symmetric 1,1 -spirobiindane-7,7'-diol were resolved with crude menthyl chloroformate by phase-transfer catalysis in the presence of tetrabutylammonium bromide. The reaction was carried out at 0℃-rt. The diastereomers of SPINOL bis-menthyl carbonate can be separated by simple crystallization using alcohol. The hydrolysis of the diastereomers was carried out via aqueous NaOH/EtOH solution.

首次通过相转移催化的方法对螺双二氢茚二酚进行了有效的拆分，用L--氯甲酸薄荷醇酯做拆分剂，以四丁基溴化铵为催化剂在0℃-室温下进行酯化反应生成非对映体衍生物，以乙醇作溶剂，通过重结晶的方法分离衍生物，在水-乙醇混合溶剂条件下，用强碱NaOH或KOH分别水解，制得相应的光学纯度大于99%ee的两个异构体SPINOL，其中总收率：--SPINOL，78.2%；--SPINOL，80.6%。

Nevertheless, the yield of pinacol was also strongly affected by the steric environment surrounding the carbonyl group. The pinacol coupling of aromatic aldehydes has been achieved with high yields under such a condition. However, the diastereose-lectivities of pinacols were not satisfying. Unfortunately, the ketones and most aliphatic aldehydes appeared inert under the same reaction conditions.

然而， 呐偶合反应的产率受到羰基周围环境的立体位阻影响较大，在此条件下，锌粉能有效地促进芳香族醛类化合物进行水相呐偶合反应，得到的呐醇产率高，但非对映异构体选择性差，而脂肪族醛类化合物得到的呐醇产率较低，在同样的条件下，酮类化合物不能顺利进行呐偶合反应。

The effect of silicon atom in substrate on the reaction rate and the stereoselectivity of enzymatic reactions was revealed by comparison of horse liver alcohol dehydrogenase-catalyzed stereoselective dehydrogenation of the three isomers of acetyltrimethyl propanone and their carbon analogues in aqueous/organic biphasic systems.

本项目通过对比在水－有机溶剂两相系统中，马肝醇脱氢酶催化三甲基硅烷丙酮的三个异构体及其碳类似物的光学选择性脱氢反应，揭示了底物中的硅原子对酶反应速度、立体选择性的影响规律，成功地合成了高对映体纯度的手性有机硅醇，并实现了辅酶的再生。

Fourthly, The preparation of 1 -triazolyl-2-isoxazolinyl substituted-ethenes was developed through an one-pot 1, 3-dipolar cycloaddition of NaN_3 and RI,α-alkylation reaction of substituted allyl bromides and 1, 3-dipolar cycloaddition of nitrile oxidesbased on polystyrene-supported propargyl selenide.

四、从聚苯乙烯负载的炔丙基硒醚出发，通过与叠氮化钠和碘化物的一锅法1，3-偶极环加成反应、取代烯丙基溴的α-烷基化反应和腈氧化物的1，3-偶极环加成反应固相合成了1—三唑—2—异噁唑啉取代的-乙烯。

A desulfurization method is proposed for the removal of sulfur compounds from FCC gasoline by alkylation reaction of thiophenic sulfur with olefins over acid catalysts, and the higher boiling sulfur-containing products are removed by fractional distillation.

选择以噻吩的甲基取代衍生物(包括 2-甲基噻吩、3-甲基噻吩及 2，5-二甲基噻吩)与异丁烯的烷基化反应为模型反应，考察了经三氯化铝气相固载法改性的 CT175 树脂催化剂催化噻吩的甲基取代衍生物与烯烃的烷基化反应性能。

She is shaped microfiber nylon bristles brush clearance axis function, with the function and application of clean water rolling every blade of tongue pressure to offset the removal of adsorbed functional integration, Trinity, and its fiber bristles of the softness and flexibility of the blade of tongue cleaning pursuit of the finer more comfortable, more clean brush principle, to create a S, C, L, M, U-shaped fiber brush tube axis by measuring the quality of Shenzhen Institute of test showed that the degree of its cleaning, and can be used as blade of tongue and mucous membrane, such as wrinkle-wall soft-tissue-specific cleaning products.

她是将异形超细纤维尼龙刷毛轴的清刷功能，与水流清洁功能和运用滚动隔压以抵消舌面吸附的清除功能相融合，三位一体，其纤维刷毛的柔软性和弹性，对舌面清洁追求越细越舒适、刷得越干净的原则，制造出S、C、L、M、U形纤维的管型轴刷，经深圳市质量计量检测研究院测试表明，其清洁程度好，可作为舌面及粘膜皱壁等软组织的专用清洁产品。

In order to analyze the thermal cracking products of fuels, we set up a GC analytical system. The gas products, which comprise methane, ethane, ethylene, propane, propylene and other gases, were collected and analyzed by gas chromatography provided with a flame ionization detector . We calculate the theoretical heat sink of n-heptane at the temperature of 600℃ and 800℃. The theoretical heat sink calculation of iso-octane at 700℃ is also related.

建立了用于分析裂解产物的气相色谱分析系统，解决了本研究中对气态裂解产物的分析要求，特别是气态小分子饱和烃和不饱和烃的有效分离；并根据裂解产物的组成及其生成热数据，对正庚烷在600℃和800℃，异辛烷在700℃时裂解的热沉进行了理论计算。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。