查询词典 Lewis

The organoboron compounds in this paper are based on triarylboranes, boronic acids and boronic esters. The structure-property relationship and sensing mechanism are elucidated. Organoboron compounds as Lewis acid can be used as fluoride probe with high sensitivity and selectivity because they have a unique LUMO in which the π-conjugation is divergently extended through the vacant p-orbital of the boron atom. The complexation of the boron π-electron systems with fluoride ion would interrupt the π-conjugation extended through the boron atom, causing the change of photophysical properties.

介绍了基于三芳基硼化合物、硼酸和硼酸酯的有机硼化合物在氟离子检测中的应用，评述了这些化合物的结构和检测性能之间的关系，讨论了检测机理，即有机硼化合物中硼原子空的p轨道使其作为路易斯酸能够选择性地结合氟离子，硼原子与氟离子的结合破坏了硼中心与芳香取代基的p-π共轭，引起有机硼化合物光物理性质的变化，从而实现对氟离子的高选择性检测。

The protic- or Lewis acid catalyzed ring-closure of divinyl ketones (and their acid-labile precursors) pentadienylic cations is known as the via Nazarov cyclization.

质子酸或路易斯酸通过戊二烯基阳离子催化二乙烯酮的环闭合（以及它们的酸不稳定前体）这个反应被称为Nazarov环化。

This study chose the Lewis, a new strain rats to have successfully established the model of regional cerebral infarction using the thread to embolize and fasten the internal carotid artery where located distantly to the bifurcation of the pterygopalatine artery and ICA, and the results had been compaired with that of SD rats.

本研究采用线栓并环扎颈内动脉与翼颚动脉分叉处远端的ICA，并在一种新品系Lewis大鼠上成功地建立了局灶脑缺血模型，并与SD大鼠进行了对比。

Compared with control,①the mean tumor weight of H22 of SXKA Granules three dose groups were decreased significantly(P.01,P.05),and the mean inhibition rates of SXKA Granules 20、10 g/kg dose groups were above 30%;②the mean tumor weight of S180 of SXKA Granules three dose groups were decreased significantly(P.01),and the mean inhibition rates of SXKA Granules 20、10 g/kg dose groups were above 32%;③the mean tumor weight of EAC of SXKA Granules three dose groups were decreased significantly ( P.01, P.05),and the mean inhibition rates of SXKA Granules 20 g/kg dose groups were above 38%;④the mean tumor weight of Lewis carcinoma of SXKA Granules three dose groups were decreased significantly(P.01, P.05),and the mean inhibition rates of SXKA Granules 20、10、5 g/kg dose groups were above 36%;⑤the mean tumor weight of W256 of SXKA Granules three dose groups were decreased significantly ( P.01, P.05),and the mean inhibition rates of SXKA Granules 20、10 g/kg dose groups were above 32%;⑵Compared with control,SXKA Granules 20、10 g/kg dose groups had extended the survial time of the P388-bearing mice respectively(P.01),and the mean prolong rates of SXKA Granules 20、10 g/kg dose groups were above 50%;⑶Compared with S180-bearing group, SXKA Granules 20、10 g/kg dose groups could increase the weight of thymus and spleen, Spleen index and thymus index were increased, SXKA Granules 5 g/kg dose group could increase thymus index(P.05);⑷As Compared with control group, SXKA Granules 20、10 g/kg dose groups could improve mouse serum half hemolysis value depressed by transplanted tumor dramatically(P.01), which revealed the SXKA granules could improve the mouse humoral immunity system;⑸SXKA Granules 20 g/kg dose group could increase of englobe indexαon S180-bearing mice remarkably(P.01), which indicated the SXKA Granules could improve their cellular immunity system.

对荷W256大鼠，生兴克癌冲剂20、10、5 g / kg三组的平均瘤重明显低于对照组(P.01，P.05)，生兴克癌冲剂20、10 g / kg组的平均肿瘤抑制率均大于32 %；⑵与空白对照组相比，生兴克癌冲剂20、10 g/ kg能显著地延长移植小鼠白血病P388小鼠的存活天数(P.01)，生兴克癌冲剂20、10 g/ kg对荷白血病P388小鼠生命延长率均在50%以上；⑶与S180荷瘤组相比，生兴克癌冲剂对荷瘤鼠的免疫器官重量、胸腺指数和脾指数有一定的提高趋势，其中生兴克癌冲剂5 g / kg组对荷瘤小鼠的胸腺指数有一定的提高作用(P.05)；⑷与S180荷瘤组相比，生兴克癌冲剂20、10 g /kg组可提高由荷瘤引起的小鼠血清半数溶血素值的降低(P.01)，表明其可提高荷瘤小鼠体液免疫功能；⑸与对照组相比，生兴克癌冲剂20 g /kg组可提高荷S180肉瘤小鼠的免疫吞噬系数α值(P.01)，表明其可提高荷瘤小鼠细胞免疫功能。

The nature of adsorbed intermediates detected by IR are:a π-allylic intermediate;an enolic type compound formed in the presence of Bronsted acid sites;a π-boned propylene species interacting with Lewis acid sites.

nsted酸位作用形成的烯丙醇物种；异丙醇中间物种。

Q. (Livio Oricchio – O Estado de Sao Paulo) Lewis, last year in Interlagos you made a mistake in the last race.

问： （利维奥Oricchio -啊斯卡德圣保罗）刘易斯去年在英特拉格斯你犯了一个错误的最后一场比赛。

Lewis was a victim of a system called "fagging" in which the older, stronger boys at the school were not only permitted, but encouraged, to boss around the younger ones.

刘易斯是一个受害者的系统被称为& fagging &中，老年人，更有力的男孩在学校不仅是允许的，但鼓励，以老板的年轻一代。

"We continue to look for ways to combat health disparities in the United States and throughout the world," said Lewis Roberts, M.B.Ch.B., Ph.D., the study's principal inestigator and a gastroenterologist at Mayo Clinic."Our research into SULF2 suggests a number of promising possibilities for the deelopment of more effectie treatments for cancer."

&我们一直在寻找与全美和全世界健康差异斗争的方法，& Lewis Roberts博士说，主要的研究者和Mayo临床中心的胃肠病学家，&我们对SULF2的研究说明，研制对肿瘤更有效的治疗方案的可能性是存在的。&

Van Gundy has confidence in his players, but he knows how valuable Lewis is.

大范对自己的球员很有信心，但他也知道刘易斯的价值。

It may be concluded that the Fe_2O_3/MgO sites,localized on Mg atoms,are acidic(presumably Lewis-type) in nature and that these results provide evidence for the heterolytic decay of the hydroperoxide to phenol and acetone.It was found that the activity of the catalysts had relationship with their redox behaviour.

氧化催化剂的活性与其氧化还原性具有一定的相关性，催化剂还原性越好，越容易导致异丙苯过氧化氢分解，进而促进异丙苯的转化。

Cable dampener cannot be rolled up but must be hung over the cable.

缆帆不能被卷起，必须保证处于展开状态

"This skylark is a present from my master," he says.

"这只云雀是我主人献上的礼物。"他说。