氢离子

A one-pot chemoselective reduction and lactonization of(4S,5R)-hemiesters was carried out to afford high-yielding(3aS,6aR)-lactone,a key chiral building block for the biotin synthesis. One-step introduction of carboxybutyl chain onto(3aS,6aR)-thiolactone was reached upon treatment of zinc reagent 25 in the presence of nanopalladium via an improved Fukuyama coupling under mild reaction conditions.

在侧链引入过程中，采用纳米钯LDH-Pd~0为催化剂以改进的Fukuyama偶联反应一步高效地引入-生物素五碳羧酸侧链，紧接着创造性地以离子氢化的方式建立了-生物素的第三个手性中心。

We used neuron from Lymnaea stagnalis to determine how lidocaine affects in, Na-H exchanger, and in.

我们用椎实螺属神经元来测定利多卡因如何影响细胞内 PH 值、钠氢交换及细胞内钠离子浓度。

The product was immiscible with catalyst/water and could be separated simply by filtration after the reaction. This method is manipulatively simple, environment-friendly and the catalyst is reusable.

反应生成的取代氢化氧杂蒽与离子液体的水溶液不相溶，通过简单的过滤可实现产物与催化体系的分离，简化了分离过程，方法操作简便、环境友好、催化剂可回收并重复使用。

Objective To investigate the degeneration of dopaminergic neurons induced by MPP+ in mouse mesencephalic dissociated culture.

目的：探讨1-甲基-4-苯基-四氢吡啶离子（1-methyl-4-phenyl-1，2，3，6-tetrahydropyridine，MPP+）诱导小鼠胚胎中脑原代培养多巴胺能神经元损伤。

Objective To investigate the degeneration of dopaminergic neurons induced by MPP+ in mouse mesencephalic dissociated culture and establish the cell model for parkinson'[KG-*3]s disease research in vitro.

目的： 探讨1-甲基-4-苯基-四氢吡啶离子对小鼠胚胎中脑原代培养多巴胺能神经元的毒性作用及其机制。

At the present time, It is a major method of research on the thermostability of thermozymes to compare the homology of amino acid sequence between thermozymes and mesophilic enzymes.

螺旋的稳定性使嗜热酶在二级结构上更稳定。在高级结构中，&额外&的离子键、疏水作用、氢键、寡聚体的形成等对嗜热酶的耐热性起主要作用。

Secondly, the silver based catalysts modified by phosphorus, zirconium, zinc, potassium and so on using molecular sieve as carrier, which were produced by ion-exchange method, had also good catalytic performance for 1,2-propane glycol oxidation to methylglyoxal. The conversion of 1,2-propane glycol and the selectivity of methylglyoxal were both high, and the impurity such as formaldehyde and acetaldehyde in the product is little. At the condition of the temperature 300 ℃, the molar ratio of oxygen to 1,2-propane glycol 1.7:1, the space velocity 6000h~(-1), and the concentration of 1,2-propane glycol 70wt%, the conversion of 1,2-propane glycol is 90% and the selectivity of methylglyoxal is 45% on the Ag-P catalyst.

其次对采用离子交换法制备的负载在分子筛上的银系催化剂进行了研究，发现此催化剂在助催化剂磷、锆、锌、钾等的作用下对丙二醇的低温氧化脱氢具有很高的活性，可以得到较好的丙酮醛的收率，并且产物中的甲醛、乙醛副产物的量比较低；经过对Ag-P催化剂上反应条件的考察，发现当温度为300℃、氧醇比1.7：1、空速6000h~(-1)、丙二醇浓度为70wt%时，丙二醇的转化率为90%，丙酮醛的选择性为45%。

Thepotential energy surface of these reactions were plotted, and the energy barrier of the reaction between THF and secondary oxonium ion was determined to be 182.0.116 kJ/mol.

本文进一步对四氢呋喃阳离子开环聚合反应过程中，氧鎓离子与水反应的机理进行了分析。

As to butylene oxide and secondary oxonium ion the barrier was determined to be 92.672kJ/mol.The reaction between oxonium ion and water in the polymerization of THF was investigated too.

结果表明，与四氢呋喃单体相比，水更容易与氧鎓离子发生反应，因此可以用水作为中止剂，来控制聚合产物的分子量。

Al (OC3H7)3 was added to an excess of distilled water (Al : H2O = 1:60-100 ) under vigorous stirring. Nitric acid [HNO3] was then added to peptize the hydroxide precipitate (Al: HNO3 = 1: 0.16). The reaction vessel was then closed and maintained for 48h at 90° C to get clear boehmite sol.

水解和缩聚反应的最终产物为非晶态的一水氢氧化铝，由许多 AlOOH 相互聚合交联形成的胶核处于中心位置，其外层是紧密吸附的同种离子 Al2O22+，它们共同构成了胶粒。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。