共价键

The method involves exposing the cells to a compound having the formula I in which: w is a nucleic acid x is a non-amino acid or non-peptide nucleic acid binding group y is a spacer having a chain length equivalent to 1-30 carbon-carbon single covalent bonds or is absent R4 is H or halogen or CH2O-R3; and R1, R2 and R3 are the same or different and are either hydrogen, methyl, ethyl, alkyl, alkenyl, hydroxylated alkyl, hydroxylated alkenyl groups or ether containing alkyl, alkenyl, hydroxylated alkyl or hydroxylated alkenyl groups optionally being an acyl group having a carbon chain length equivalent to 3-24 carbon atoms saturated or unsaturated, with the proviso that at least one of R1, R2 or R3 includes a group having a carbon chain of 3-24 carbon atoms saturated or unsaturated, or to a compound having the formula II in which: w is a nucleic acid x is a non-amino acid or non-peptide nucleic acid binding group y is a space having a chain length equivalent to 1-30 carbon-carbon single covalent bonds or is absent, R5 is alkyl, alkenyl, hydroxylated alkyl, hydroxylated alkenyl group or ether containing alkyl, alkenyl, hydroxylated alkyl or hydroxylated alkenyl group optionally being an acyl group having a carbon chain length equivalent to 3-24 carbon atoms saturated or unsaturated, with the proviso that R5 includes a group having a carbon chain of 3-24 carbon atoms saturated or unsaturated.

该方法包括使细胞暴露于具有式的化合物，在式中：w是核酸，x是非氨基酸或者非肽核酸结合基团，y是具有等于1―30个碳―碳单共价键的链长的间隔基或者不存在，R4是H或者卤素或者CH2O－R3；R1、R2和R3是相同的或者不同的并且是氢、甲基、乙基、烷基、链烯基、羟基化烷基、羟基化链烯基或者包含烷基、链烯基、羟基化烷基或羟基化链烯基的醚，任选地是来源于具有等于3―24个碳原子的碳链长的饱和或不饱和脂肪酸的酰基，其条件是R1、R2或者R3的至少一个包括具有3―24个碳原子的饱和或不饱和碳链的基团，或者使细胞暴露于具有式的化合物，在式中：w是核酸，x是非氨基酸或者非肽核酸结合基团，y是具有等于1―30个碳―碳单共价键的链长的间隔基或者不存在，R5是烷基、链烯基、羟基化烷基、羟基化链烯基或者包含烷基、链烯基、羟基化烷基或羟基化链烯基的醚，任选地是具有等于3―24个碳原子的饱和或不饱和碳链的链长的酰基，其条件是R5包括具有3―24个碳原子的饱和或不饱和碳链的基团。

It can be obtained that the structure of liquid Fe〓Si〓 alloys changes to be more open with increasing Si concentration. The Gauss decomposition of radial distribution function exhibits a Gaussian peak at about r=0.370nm on RDF of pure liquid Si as well as Fe-Si alloys, which means there are Si-Si covalence both in pure liquid Si and Fe-Si alloys.

对纯Fe、纯Si和Fe-Si合金的径向分布函数的Gauss分解显示，在纯Si径向分布函数的r=0.370nm附近存在一Gauss峰，表明纯Si熔体中存在Si-Si共价键；而在Fe-Si合金径向分布函数的同一距离范围内也存在一Gauss峰，表明Fe-Si合金熔体中也存在Si-Si共价键。

In this dissertation, a series of ultra-thin films based on photosensitive diazoresin were fabricated through layer-by-layer self-assembly technique, and the films could be attached by covalent bond after the decomposition of diazonium group between layers under UV irradiation.

本论文利用层层自组装技术，制备了基于光敏性重氮树脂的系列超薄膜，这种感光性组装膜在紫外光照射下能够形成共价键联结，本论文着重对这些共价键联结超薄膜的功能特性进行了研究，主要结果如下

Each In atom is bonded with one Si atoms and two neighboring In atoms; b The adsorption energy of single In atom on the FHUC of the Si(111)-7x7 is 0.2eV higher than that on the UHUC. As a result, In atoms prefer to enucleate at the UHUC and develop into ordered dots array accordingly.

第一原理计算表明， a六个 In 原子在 Si(111)-7x7表面形成一种扭曲的六边形结构，每个 In 原子与一个衬底 Si 原子及两个相邻的 In 原子形成共价键，这些共价键具有类 sp2构型； b单个 In 原子吸附在 Si(111)-7x7单胞的 FHUC 时的吸附能较吸附在没有层错的一半的吸附能低0.2eV/原子，故而 In 团簇优先在 FHUC 成核生长并进而形成有序的点阵结构。

The results show that the major contribution to DOS of Mg and Pb are the 2p orbit of Mg and the 5d orbit of Pb, followed by the 3s orbit of Mg and the 6p orbit of Pb, the 6s orbit of Pb is the smallest one. There are a large number of charges around Mg, it has the characteristics of typical metal bond. Mg and Pb share some charges to form covalent bond, but the distortion of the charge at the junction is little; the proportion of covalent bond is less than the metal bond, Mg2Pb is semimetal. The elastic modulus and shear modulus of Mg2Pb are 68.6 and 27.9 GPa, respectively. Based on Pugh empirical criterions and Poisson's ratio, Mg2Pb is brittle in nature.

结果表明：Mg和Pb对态密度的贡献主要是Mg的2p轨道和Pb的5d轨道，其次为Mg的3s轨道和Pb的6p轨道，Pb的6s轨道贡献最小；在Mg原子周围有大量的电荷存在，呈典型的金属键特征，Mg、Pb之间存在共用的电荷，有较强的离域性，以共价键形式存在，但交界电荷的畸变不大，故共价键所占比例较少，金属键所占比例较大，Mg2Pb化合物呈半金属性；Mg2Pb的弹性模量和切变模量分别为68.6和27.9 GPa，Pugh经验判据和泊松比均表明Mg2Pb具有脆性。

The present research work focuses on two aspects. On one hand, the most successful alkaloid-derived ligands have been attached to a soluble or insoluble support covalently, but additional OsO〓 is necessary to maintain the consistent catalytic activity during the reuse of supported chiral ligand in the next AD reaction. On the other hand, immobilization of osmium tetroxide based on microencapsulation, ion-exchange techniques, and osmylation of resins has made it possible to recover and reuse of the osmium, but failed to recover the chiral ligand at the same time.

目前的研究主要集中在两个方面：一方面，将手性配体共价键合到不溶或可溶性载体上制成负载手性配体，但在重复使用负载配体时必须补充OsO〓，才能保证催化活性不降低；另一方面，将OsO〓包裹在高聚物微囊内，或运用离子交换技术或共价键合的方法将OsO〓固载在树脂、硅胶或层状双金属氢氧化物材料上，但手性配体却不能同时回收。

The result showed that Si--Si covalent bond eAsts in the melt of eutectic and hyper--eutectic alloy and Sr has capability to weaken the coto bond.

结果表明，在共晶及过共晶的合金的液态结构中，存在着Si—Si共价键，Sr有削弱这些共价键的倾向。

In addition to the two axial ligations provided by His18 and Met80, the hydrogen bond and hydrophobic interactions between the heme and the protein polypeptide, the heme also covalently linked to the protein matrix through two thioether bonds which are formed between vinyl groups of the heme and cysteine residues of a classic Cys-Xaa-Xaa-Cys-His heme-binding motif of the polypeptide chain.

Cyt c是血红素蛋白中电子传递蛋白的典型代表，其辅基heme与蛋白肽链的结合除了来自heme轴向配体组氨酸(His18)和甲硫氨酸(Met80)的配位作用、氢键和疏水相互作用等非共价键作用方式外，血红辅基heme的两个乙烯基还与蛋白肽链上的结构片段域Cys-Xaa-Xaa-Cys-His中的两个半胱氨酸形成硫醚键以共价键方式相结合。

The specific decomposition of the terms depends on the force field, but a general form for the total energy in an additive force field can be written as where the components of the covalent and noncovalent contributions are given by the following summations

特别的分解项依赖于力场，但是总能力的一般的形式在增加力场可以写为，这里共价键和非共价键贡献可以写为

The results of its intrinsic fluorescence spectroscopy and fluorescence phase diagram showed that when the guanidine hydrochloride concentration in denaturation solution was about 1.0 mol/L, there existed a partially folded intermediate of Bacillus amyloliquefaciens a-amylase during its unfolding procedure, which followed a three-state model; the result of its fluorescence probe showed that when the guanidine hydrochloride concentration in denaturation solution was about 1.0 mol/L, there existed some stable hydrophobic regions, which could interact with a hydrophobic reagent 8-anilino-1-naphthalene sulfonic acid, in the partially folded intermediate of Bacillus amyloliquefaciens a-amylase; and the results of fluorescence quenching using acrylamide and potassium iodide as quenchers showed the distribution of Trp residues in Bacillus amyloliquefaciens a-amylase in different denaturation solution, with the maximum number (8) of tryptophan residues in a partially folded intermediate Bacillus amyloliquefaciens a-amylase molecule could be quenched by potassium iodide; and the results of their protein electrophoresis and SEC showed that no aggregate or aggregate precipitation of Bacillus amyloliquefaciens a-amylase formed during the whole unfolding procedure of Bacillus amyloliquefaciens a-amylase induced by guanidine hydrochloride.

内源荧光光谱和荧光相图结果表明，当变性液中盐酸胍浓度约为1.0 mol/L时，芽孢杆菌a-淀粉酶的去折叠过程中出现一个部分折叠中间体，其去折叠过程符合&三态模型&；荧光探针结果表明，在溶液中盐酸胍浓度约为1.0 mol/L时，中间态芽孢杆菌a-淀粉酶分子中存在着能够与探针分子1-苯胺基-8-萘磺酸结合的稳定的疏水区域；荧光猝灭研究给出了不同程度变性的淀粉液化芽孢杆菌a-淀粉酶中的Trp的分布情况，结果表明中间态芽孢杆菌a-淀粉酶分子中能够被碘化钾猝灭的位于分子表面的色氨酸残基数目达到最大的8个；蛋白电泳和体积排阻色谱结果表明，在盐酸胍诱导的芽孢杆菌a-淀粉酶分子的整个去折叠过程中，不会以共价键或非共价键形式形成芽孢杆菌a-淀粉酶分子之间的集聚体或集聚体沉淀。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。